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Idea 03 of 06Borrowed from plant physiology of conifer wood

Pressure-driven foam plugs make a breathable nonwoven liquid-tight

Borrowing the bordered pit valve of conifer wood, we seat a foam plug in each pocket of a film-free web, so liquid pressure seals it while dry areas breathe.

Fig. 1A conifer's bordered pit valve and the proposed outer cover share one move: a solid disc, held loosely in an open fibre mesh, is pushed by the pressure itself onto a solid rim, sealing only where load arrives.
Fig. 1

Pressure-driven foam plugs make a breathable nonwoven liquid-tight

A wide painted scene. On the left a conifer stands in a misty forest beside a sawn log, whose plank surface runs on into a wooden table on the right where a disposable diaper lies outer cover up, one corner cut away to show its layers. Two circular insets along the bottom show the same thing: on the left, a solid red disc in a chamber inside a wood cell wall, pushed up by an arrow onto the rim of the opening above it and hung on loose green strands; on the right, thin red foam plugs in a honeycomb of pockets, pushed up by blue liquid from below onto smooth tan rims around the narrowed pocket mouths, with loose green fibres underneath.

A conifer's bordered pit valve and the proposed outer cover share one move: a solid disc, held loosely in an open fibre mesh, is pushed by the pressure itself onto a solid rim, sealing only where load arrives.

What is this idea, and what's clever about it?

In a film-free web the barrier is usually a fixed property of the whole face, set by the largest pore and by how the fluid wets the fibres, so tightening it also closes the air path and stiffens the sheet. The conifer faces the same task, holding a pressure difference across a structure that is otherwise open to flow, and solves it with a solid disc larger than the opening it closes, sealed by contact pressure against a rim. Carried over, the load-actuated seal exists only where and while liquid presses and grows tighter as pressure rises; because the seal is solid against solid, it may also hold against low-surface-tension fluids such as menses, where water-tuned webs over-predict their barrier.

Where we’ve seen this before

Where is it inspired from?

Fig. 2In conifer wood, a solid disc hung on a loose fibre mesh is pushed onto the rim of the opening between cells; under the same pressure the open mesh alone would let air through.
Fig. 2

Pressure-driven foam plugs make a breathable nonwoven liquid-tight

Two panels. Left, a conifer in a forest with a magnifier on a split piece of its wood, showing long water-conducting cells with rows of small round valves in their walls. Right, two identical cross-sections of one valve under the same upward push from an air-filled cell below. In the first, a solid red disc on loose green strands is pressed flat against the rim around the opening into the water-filled cell above, and the air is stopped. In the second, the same strands have no disc, and air bubbles pass through the open mesh into the water.

In conifer wood, a solid disc hung on a loose fibre mesh is pushed onto the rim of the opening between cells; under the same pressure the open mesh alone would let air through.

The bordered pit valve of conifer wood stops an air bubble in one water-conducting cell from spreading to its neighbours 1. A solid, impermeable disc, wider than the opening it covers, hangs on a loose fibre mesh anchored to the pit rim 12. Normally water flows through the open mesh, which resists flow about 59 times less than the pit membranes of flowering trees 3. When one cell fills with air, the pressure difference pulls the disc onto the rim and closes the opening 1. In the living tree, the mesh springs the disc back once the difference falls.

Models of black spruce pits put the pressure difference needed to pull the disc shut at 0.894 MPa in stems and 0.644 MPa in roots 4. In Douglas-fir, forcing air past a closed disc takes more pressure than closing it 5. The small contact area raises the contact pressure at the rim above the air pressure 6. The seal is the most likely failure site, and disc–rim adhesion may be the main factor in resistance 2.

How does it transfer?

A structure that must stay open to flow can still hold back a pressure difference if the barrier is a separate impermeable plug, larger than the opening it closes, held loosely in a compliant open mesh and driven by that pressure difference onto a solid seat. The barrier then exists only at the loaded site and only while the load lasts, and the seat sets how much pressure it holds.

  • Thickened impermeable central disc of the pit→Foam plug, a closed-cell foam disc
  • Loose radiating strand mesh suspending the disc→Fibre layers holding the plug lifted
  • Solid rim around the pit opening→Fused seat lattice melted from the web's polypropylene
  • Pit cavity the disc travels across→Pocket with a mouth narrower than its interior
  • Disc larger than the opening, resisting being pushed through→Plug shoulder caught under the pocket mouth
  • Closure driven by the air–water pressure drop→Load-actuated seal, closed by the pressure of arriving liquid
What does not carry over
  • The bordered pit valve seals at pressures of roughly 0.6 to 0.9 MPa in water-filled wood, and that large safety margin does not carry over to a web that must reach a 62 mbar liquid holdout pressure, so the design instead depends on a continuous, leak-free fused seat lattice and on keeping the fused area small.
  • The tree's valve stops air from entering conduits already full of water and reopens only while the wood stays living and wet; the web works the other way round, starting dry and open to gas so that no pressure difference builds before liquid arrives, and it relies on the foam's own recovery and the fibre layers to lift the plug again.
  • The tree grows its disc from pectin and its strands from cellulose; the design grows one closed-cell foam plug in each pocket from a metered foaming precursor, and the pocket's narrowed mouth, set by the forming tool, takes the place of the disc's natural size margin over the opening.

How does it work?

The design is a film-free nonwoven web of about 35 gsm. Each small pocket in the web holds an airtight foam plug. When liquid presses on the web, the pressure pushes each loaded plug onto a solid ring and seals that pocket. When the web is dry, air and vapour pass around the plugs.

  1. Form pockets and melt their walls solid

    A honeycomb of six-sided pockets is formed into the fibre layers at 0.5 mm pitch, and each pocket's mouth is narrower than its interior. The tops of the pocket walls are then melted solid into a fused seat lattice. Ultrasonic welding of polypropylene nonwovens is shown to leave melted zones without cracks or blowholes 7. The fused share of the face is projected at about 12.4 %, and it is a trade-off: a larger share stiffens the web and a smaller one leaves more room for leak paths.

  2. Grow one foam plug per pocket

    A liquid foaming precursor is spread over the body side. The fine fibre mesh holds it over each pocket by capillary action, the wicking that fibre reinforcements are known to show 8, and the non-porous fused tops let it drain away. The precursor expands inside the pocket until the cavity and the narrow mouth stop it 9, which leaves one foam plug wider than the mouth and trapped beneath it. The plug's sealing face is formed against the same polished tool face as the seat ring, so both faces come from one surface.

  3. Dry web: plugs stay lifted, air passes

    At rest each foam plug is projected to sit 5–15 µm above its seat. Air and vapour pass through the gap around the plug's edge and then through the coarse pores of the fibre layers below. The bottom layer is open to gas, so cuff and body compression on a dry core cannot build a pressure difference across a plug, and the plugs stay open while the article is worn.

  4. Wet web: pressure drives each plug shut

    Liquid that seals the bottom layer creates a pressure difference, and that difference forces each loaded plug onto its seat. This is the load-actuated seal. At the 62 mbar requirement, the force on the mouth is concentrated onto a much smaller seat ring, a projected average contact pressure of about 44–49 kPa. In conifer wood, where a small disc pressed against a pore rim seals it, models show that the limited contact area lifts contact pressure above the pressure being held 6. Seal pressure rises with load, the plug lifts again elastically when the load falls, and the seal's insensitivity to the liquid's surface tension is untested.

Fig. 3In the proposed outer cover, each foam plug sits clear of its fused seat while dry, is pressed onto the seat when liquid pushes, and returns when the pressure falls.
Fig. 3

Pressure-driven foam plugs make a breathable nonwoven liquid-tight

Three cross-sections of the same small strip of the proposed outer cover, left to right. Each shows three honeycomb pockets whose solid tan wall tops narrow the pocket mouths, a thin red foam plug inside each pocket, loose green fibres below and the absorbent core at the bottom. First: dry, with air arrows passing up through the fibres and around the plugs' edges. Second: blue liquid soaks up from the core and presses the plugs flat against the rims, and the top stays dry. Third: the liquid has fallen back, the plugs have moved back down off the rims, and the air arrows return.

In the proposed outer cover, each foam plug sits clear of its fused seat while dry, is pressed onto the seat when liquid pushes, and returns when the pressure falls.

Why do we think it will work?

The parts of this idea that already work somewhere, and how each carries over here.

Part of the ideaWhere it already worksHere
Conifer wood water transport · Bordered pit valve in black spruce

Solid-mechanics models built from microscope images of black spruce pits give average sealing pressures of 0.894 MPa in stems and 0.644 MPa in roots, with considerable variation between individual pits. 4

What is the evidence it will work?

Pressure-driven disc valve sealing on a rim

Where it works
Conifer wood water transport · Bordered pit valve in black spruce
What it does there
Solid-mechanics models built from microscope images of black spruce pits give average sealing pressures of 0.894 MPa in stems and 0.644 MPa in roots, with considerable variation between individual pits.
Here
Carries over if: The same force balance still closes a foam plug on its seat at the 62 mbar target, roughly a hundred times below the pressures at which the wood valve operates.
The evidence

Carries over ifThe same force balance still closes a foam plug on its seat at the 62 mbar target, roughly a hundred times below the pressures at which the wood valve operates.Tested in What we’d test →

Conifer wood water transport · Bordered pit valve central disc

The central disc has "a diameter greater than that of the pit apertures", and the pressure difference deflects the membrane so the disc plugs the aperture; pull-through of the disc was also observed under load. 1011

What is the evidence it will work?

Plug wider than the opening it closes

Where it works
Conifer wood water transport · Bordered pit valve central disc
What it does there
The central disc has "a diameter greater than that of the pit apertures", and the pressure difference deflects the membrane so the disc plugs the aperture; pull-through of the disc was also observed under load.
Here
Carries over if: A pocket mouth narrower than its interior holds a foam plug against the 62 mbar differential without the plug being pushed through.
The evidence

Carries over ifA pocket mouth narrower than its interior holds a foam plug against the 62 mbar differential without the plug being pushed through.Tested in What we’d test →

Nonwoven converting and polymer welding · Roll-to-roll ultrasonic welding; laser welding

Continuously ultrasonic-welded polypropylene nonwovens showed "no welding defects, such as cracks or blowholes" in the melted zone; laser welding of thin sheets reaches 38 µm weld spots. 71213

What is the evidence it will work?

Fusing nonwoven polypropylene into solid bands

Where it works
Nonwoven converting and polymer welding · Roll-to-roll ultrasonic welding; laser welding
What it does there
Continuously ultrasonic-welded polypropylene nonwovens showed "no welding defects, such as cracks or blowholes" in the melted zone; laser welding of thin sheets reaches 38 µm weld spots.
Here
Carries over if: Bands about 50 µm wide can be fused leak-tight through the full thickness of a web weighing 20 grams per square metre (gsm), where the demonstrations are at millimetre scale on webs near 100 gsm.
The evidence

Carries over ifBands about 50 µm wide can be fused leak-tight through the full thickness of a web weighing 20 grams per square metre (gsm), where the demonstrations are at millimetre scale on webs near 100 gsm.Tested in What we’d test →

Microcellular polymer foam processing · Saturation-then-expand foaming; moulded closed-cell foams

A pressure-saturated melt, once released, "foams out to the final geometry" with closed cells of about 2 to 25 µm; supercritical-fluid foaming gives closed cells near 10 µm or less. 914

What is the evidence it will work?

Closed-cell foam expanding to fill its cavity

Where it works
Microcellular polymer foam processing · Saturation-then-expand foaming; moulded closed-cell foams
What it does there
A pressure-saturated melt, once released, "foams out to the final geometry" with closed cells of about 2 to 25 µm; supercritical-fluid foaming gives closed cells near 10 µm or less.
Here
Carries over if: A metered precursor expanded inside each 60 to 100 µm deep pocket yields one closed-cell plug near 300 kg/m³ with cells of 5 µm or less and an intact skin.
The evidence

Carries over ifA metered precursor expanded inside each 60 to 100 µm deep pocket yields one closed-cell plug near 300 kg/m³ with cells of 5 µm or less and an intact skin.Tested in What we’d test →

Optical materials and coatings · Foamed white pigments; foam-printed polymer films

Supercritical-CO₂-foamed PMMA microspheres scatter light from air-filled cavities and were "evaluated as possible replacement for TiO₂ pigments"; foamed photopolymers print white at about 20,000 dots per inch. 1718

What is the evidence it will work?

Pigment-free whiteness from air voids

Where it works
Optical materials and coatings · Foamed white pigments; foam-printed polymer films
What it does there
Supercritical-CO₂-foamed PMMA microspheres scatter light from air-filled cavities and were "evaluated as possible replacement for TiO₂ pigments"; foamed photopolymers print white at about 20,000 dots per inch.
Here
Carries over if: A 15 µm closed-cell foam plug covering most of the face scatters enough light to give the sheet contrast-ratio opacity and to mask stains.
The evidence

Carries over ifA 15 µm closed-cell foam plug covering most of the face scatters enough light to give the sheet contrast-ratio opacity and to mask stains.

Composites and technical textiles · Laid scrim laminated with foam

Nonwoven laid scrim is supplied laminated with foam as a commercial reinforcement product. 19

What is the evidence it will work?

Foam bonded onto a fibre reinforcement

Where it works
Composites and technical textiles · Laid scrim laminated with foam
What it does there
Nonwoven laid scrim is supplied laminated with foam as a commercial reinforcement product.
Here
Carries over if: Foam cast into the loose fibre layers under each pocket forms a rim soft enough to seat the plug and return it over repeated loads.
The evidence

Carries over ifFoam cast into the loose fibre layers under each pocket forms a rim soft enough to seat the plug and return it over repeated loads.Tested in What we’d test →

Hygiene nonwovens · Commercial spun-laid polypropylene sheet grades

Commercial 15 to 80 gsm polypropylene nonwovens are specified at 15 to 55 N/5 cm of strength across the roll width (cross-direction tensile); thermally bonded 8 to 30 gsm grades are a standard hygiene class. 2021

What is the evidence it will work?

Light polypropylene nonwoven carrying tensile load

Where it works
Hygiene nonwovens · Commercial spun-laid polypropylene sheet grades
What it does there
Commercial 15 to 80 gsm polypropylene nonwovens are specified at 15 to 55 N/5 cm of strength across the roll width (cross-direction tensile); thermally bonded 8 to 30 gsm grades are a standard hygiene class.
Here
Carries over if: The chosen 15 to 19 gsm fibre layers keep cross-direction strength above the 12.9 N/50 mm requirement after the pockets are formed and the seat lattice is fused.
The evidence

Carries over ifThe chosen 15 to 19 gsm fibre layers keep cross-direction strength above the 12.9 N/50 mm requirement after the pockets are formed and the seat lattice is fused.

What's different?

The liquid barrier becomes the closed state of discrete foam plugs that liquid pressure drives onto a fused seat lattice, replacing the fixed fine-pore, low-surface-energy face that film-free webs rely on today.

How it’s done todayThis idea
Barrier mechanismSmall largest pore plus low-surface-energy finish across the whole faceLoad-actuated seal: liquid pressure drives each foam plug onto its seat
State when dryBarrier always on, identical at 1 mbar and 60 mbarOpen fibre mat; only loaded pockets seal, and reopen when load falls
Response to loadFixed resistance, independent of the pressure appliedSeat contact pressure rises with the applied load
Barrier materials30–50 % meltblown (very fine melt-spun fibre) plus fluorochemical or non-fluorinated coating4 gsm (grams per m²) foam plus 4 gsm meltblown; no coating
Menses-like fluidHoldout scales with surface tension; water-tuned webs over-predictSolid-on-solid seat, so holdout depends on contact completeness
Cost and stiffnessAdded solid fraction stiffens sheet; best example about 2–3× cost ceilingBarrier adds about 8 gsm versus 40+; mass, stiffness, cost largely untouched
Closest existing work · 4
  • Poly-Bond pressure-thresholded nonwoven pouch backsheet22Its pouch turns hydrophilic above a threshold hydrohead (liquid pressure held before leaking), then absorbs fluid; here foam plugs seat and hold liquid.Google Patents ↗
  • Berry/AVINTIV 45 gsm SMMMMS with barrier coating23It reaches 81.2 mbar with fine-fibre layers and a low-surface-energy coating, a barrier that is always on; here pressure closes plugs locally.Google Patents ↗
  • Allegiance film-free S-4MB-S fluorocarbon backsheet24It stacks four meltblown plies and a fluorocarbon finish for a fixed barrier; here barrier mass is about 8 gsm, with no barrier chemistry.Google Patents ↗
  • P&G spunbond/nanofiber/spunbond film-free barrier25It sets barrier by nanofiber pore geometry, with a 10 mbar hydrohead floor; here a seated plug closes each pocket instead.Google Patents ↗

What would we test?

The riskiest open question

Once seated, a foam plug holds 62 mbar whatever the fluid's surface tension, because the seal is solid pressed on solid.

Why it matters
If the seated plug falls back to a liquid meniscus at the seam, the web holds water and leaks menses, as water-tuned fibre webs already do.
First test
Measure seated holdout on single-cell and 1000-cell coupons across five surface tensions, 72 to 30 mN/m, against roughened-skin, plug-absent and fine-fibre controls. 2930
Go if
At least 62 mbar at every surface tension, within 5% spread, while roughened and plug-absent controls fall.
No-go if
Seated holdout falls with surface tension like the controls, or misses 62 mbar at 50 mN/m.
Effort
$15K–30KUSD$15K–30Kas statedEUR€13.4K–26.8KJPY¥2.38M–4.76MECB reference rates, 2026-10-12 · 3 to 5 months
The other open questions · riskiest first

  1. The fibre-layer rim is soft enough that each foam plug stays lifted at rest and seats before liquid enters the gap around it.

    Why it matters
    Without this the array is a static barrier with no valve action, and the plug's own stiffness, near 190 N/m, is far above the roughly 38 N/m seating needs.
    First test
    On one transparent single cell, read gap entry and plug closure in the same pressure ramp while varying rim stiffness, rest lift and fluid; cycle 100 times. 1031
    Go if
    Closure precedes entry at an achievable rim stiffness and lift; plugs re-lift on at least 90% of cycles.
    No-go if
    Entry precedes closure at every rim stiffness and lift, or closure tracks surface tension instead of stiffness.
    Effort
    $8K–18KUSD$8K–18Kas statedEUR€7.15K–16.1KJPY¥1.27M–2.85MECB reference rates, 2026-10-12 · 2 to 4 months

  2. At the specified 52–56 µm width, fused seat lattice bands can be made leak-tight through a 20 gsm polypropylene web without closing nearby pocket floors.

    Why it matters
    The fused seat lattice is the ring every foam plug seals against, and at 0.5 mm pitch 52–56 µm bands cover about 20–21% of the face unless the geometry changes.
    First test
    Laser-weld coupons on a micro-ridge anvil roller, sweeping dwell; check bands by electron-microscope cross-sections and Raman mapping, floor pores by gas-flow porometry, leaks by hydrohead (water-column pressure). 353637
    Go if
    Void-free 52–56 µm bands, floor pores within 20% of unfused control, no lattice leak at 62 mbar.
    No-go if
    Band width grows with dwell past the ridge, floor pores shrink over 20%, or coupons leak at 62 mbar.
    Effort
    $20K–40KUSD$20K–40Kas statedEUR€17.9K–35.8KJPY¥3.17M–6.34MECB reference rates, 2026-10-12 · 4 to 6 months

  3. A metered precursor foams inside each pocket into one closed-cell foam plug near 300 kg/m³, with an intact skin and no bridging between pockets.

    Why it matters
    The skinned top face does the sealing, so an open-celled or breached plug leaves its pocket open.
    First test
    Dose and foam precursor over a formed pocket array; map occupancy, density, cell size and closed-cell content, then trace conductance through a 0–100 mbar cycle. 3839
    Go if
    One skinned closed-cell plug per pocket, no bridging, conductance collapsing at a threshold and recovering on release.
    No-go if
    Open-celled or breached plugs persist, bridging closes the gaps, or conductance shows no seating threshold.
    Effort
    $20K–45KUSD$20K–45Kas statedEUR€17.9K–40.2KJPY¥3.17M–7.14MECB reference rates, 2026-10-12 · 4 to 6 months

  4. The pocket mouth, narrower than its interior, holds the soft foam plug at 62 mbar over repeated loads without the plug being pushed through.

    Why it matters
    The wood valve's own disc has been seen forced out through its aperture, so the narrow mouth gives a retention mechanism but no guaranteed retention load.
    First test
    Ramp a transparent single-pocket fixture with the real foam and mouth to 6.2 kPa at 37 °C, imaging the shoulder, then cycle 100 times.
    Go if
    No prolapse, tearing or escape, and free travel retained after 100 cycles.
    No-go if
    The foam plug prolapses, tears or escapes through the mouth.
    Effort
    $10K–20KUSD$10K–20Kas statedEUR€8.94K–17.9KJPY¥1.59M–3.17MECB reference rates, 2026-10-12 · 2 to 4 months
Also to check before scale-up
  • A written ruling on whether the closed, face-covering array of foam plugs counts as film-free.
  • A fully seated, wetted array has no air path; agree whether the air-permeability floor applies to dry material only.
  • Fix one consistent band geometry: 12.0–12.8% fused face implies about 31–33 µm bands at 0.5 mm pitch.
  • Cup crush below 50 g on the real architecture; noise has no test method yet.
  • Missing-plug rate per article near 99.9998% coverage, and an inspection that can follow it at line speed.
  • Dry contrast-ratio opacity of at least 80% and stain masking from foam void scattering alone.
  • Strip tensile above about 12.9 N/50 mm in both directions and MD elongation above 5% after pocket forming and fusion, across three pilot lots.
  • Delivered cost against the €0.07/m² ceiling, and which of the two cost figures governs.

Who could help make this happen?

First contacts

2

References

103 sources43 cited in this idea, 60 background reading

Where it comes from8

Where it comes from

8

The work in the source field that the idea borrows its principle from.

  1. 1Paper: New insights into bordered pit structure and cavitation resistance in angiosperms and conifers., Choat & Pittermann2009
    B. Choat and J. PittermannNew Phytologist
    the conifer pit membrane is centrally located in the pit chamber allowing water to move through the margo unimpeded. Should one tracheid become air-filled, the pressure difference across the menisci in the margo pores will be sufficient to deflect the membrane towards the adjoining functional tracheid where Px < 0. This way, the torus is appressed against the pit aperture, thereby isolating the water-filled tracheid.
    Why it’s hereDescribes how a pressure difference pushes the conifer disc onto the aperture, isolating the water-filled cell.
    Cited in
    Where it comes from
    Open source (opens in a new tab)PDF
  2. 2Paper: Mechanism of water-stress induced cavitation in conifers: bordered pit structure and function support the hypothesis of seal capillary-seeding, Delzon et al.2010
    S. Delzon, C. Douthe, A. Sala and 1 morePlant, Cell and Environment
    it's worth noticing that the torus area is always larger than the pit aperture among the 40 conifer species sampled here (51% larger on average), which may prevent the torus from passing through the aperture
    Why it’s hereAcross 40 conifers the disc exceeds the aperture by 51% on average, keeping it from passing through.
    Cited in
    Where it comes from
    Open source (opens in a new tab)PDF
  3. 3Paper: Plasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem., Jansen et al.2012
    S. Jansen, J. Lamy, R. Burlett and 3 morePlant, Cell and Environment
    an unaspirated margo offers a pit-area resistance on average 59 times lower than an angiosperm pit membrane ... sealing seems valid up to a certain threshold ... pores occur in the torus of 13 of the species studied ... average diameter of 51 nm ... species with punctured tori are significantly less resistant to cavitation than species with non-punctured tori.
    Why it’s hereOpen fibre mesh has low flow resistance; pores in the disc make conifers less resistant to air entry.
    Cited in
    Where it comes from
    Open source (opens in a new tab)PDF
  4. 4Paper: Solid mechanics of the torus-margo in conifer inter-tracheid bordered pits., Schulte & Hacke2020
    P. Schulte and U. G. HackeNew Phytologist
    The average pressure required for sealing the pit was 0.894 MPa for stems and 0.644 MPa for roots, although considerable variation was apparent between individual pits.
    Why it’s hereMeasured sealing pressures of 0.64–0.89 MPa in conifer pits, far above the web's target pressure.
    Cited in
    Where it comes fromWhy we believe it
    Open source (opens in a new tab)
  5. 5Web page: Safety Factors for Xylem Failure by Implosion and Air-Seeding (Domec et al., IAWA Journal), fs.usda.gov
    Radial sections were used to measure the bordered pit diameter (Dp) and the pit aperture diameter (Da) ... the analysis of Douglas-fir bordered pits ... suggested that pressures required for air seeding (forcing air past the sealed torus) were greater than the pressures needed to deflect the torus enough to seal the pit.
    Why it’s hereIn Douglas-fir, air entry past a sealed disc needs more pressure than seating the disc does.
    Cited in
    Where it comes from
    Open source (opens in a new tab)
  6. 6Paper: Contact Mechanics between Torus and Pit Border for Developing Air-Seeding Seal in Aspirated Bordered Pits, Xia et al.2023
    P. Xia, J. Gu, W. Song and 4 moreForests
    Due to the limited contact area on the torus surface, the contact pressure between the torus and the pit border exceeded the air pressure in aspirated bordered pits.
    Why it’s hereContact pressure between disc and rim exceeds the applied air pressure, so the seal is solid contact.
    Cited in
    Where it comes fromHow it works
    Open source (opens in a new tab)PDF
  7. 10Paper: Force-displacement measurements of earlywood bordered pits using a mesomechanical tester., Zelinka et al.2015
    S. Zelinka, K. Bourne, J. Hermanson and 3 morePlant, Cell and Environment
    Two failure modes were observed ... stretching ... until the torus was forced out of the pit chamber through the pit aperture without rupture ... torus prolapse.
    Why it’s hereForce–displacement tests on conifer pits; shows the disc can be forced out through the aperture.
    Cited in
    Why we believe itWhat we'd test
    Open source (opens in a new tab)
  8. 11Paper: Structure and function of bordered pits: new discoveries and impacts on whole-plant hydraulic function., Choat et al.2008
    B. Choat, A. Cobb and S. JansenNew Phytologist
    Liese & Johann (1954), who showed that margo pores are commonly up to 200 nm in diameter ... air seeding will always occur at the largest pore that connects two vessels, therefore the air-seeding threshold between vessels depends on the maximum rather than the average diameter of pit membrane pores.
    Why it’s hereAir enters at the largest mesh pore, so the largest gap, not the average one, sets where air gets through.
    Cited in
    Why we believe it
    Open source (opens in a new tab)PDF
Evidence it works16

Evidence it works

16

Each shows a part of the idea already working somewhere.

  1. 7Paper: Effects of Different Roller Profiles on the Microstructure and Peel Strength of the Ultrasonic Welding Joints of Nonwoven Fabrics, Nguyen et al.2020
    T. Nguyen, L. Q. Thanh, L. Nguyen and 2 moreApplied Sciences
    no welding defects, such as cracks or blowholes, were visible in the melted zone
    Why it’s hereUltrasonic welds in polypropylene nonwovens show no cracks or blowholes, the void-free fusion the seat lattice needs.
    Cited in
    How it worksWhy we believe it
    Open source (opens in a new tab)PDF
  2. 8Paper: Capillary wicking in a fibrous reinforcement – Orthotropic issues to determine the capillary pressure components, Pucci et al.2015
    M. F. Pucci, P. Liotier and S. DrapierComposites Part A: Applied Science and Manufacturing
    A porous structure has been approximated to a capillary tube network in numerous studies... the Washburn equation... was modified and extended to describe the capillary wicking in a fibre bundle
    Why it’s hereModels capillary wicking into fibre bundles with an extended Washburn equation, the basis for metering the precursor.
    Cited in
    How it works
    Open source (opens in a new tab)
  3. 9Patent application: Microcellular closed cell foams and their method of manufacture, US 4,473,665 A1982
    Massachusetts Institute of TechnologyInventors: J. E. Martini-Vvedensky, N. P. Suh and F. A. Waldman
    The part will then expand as the plastic ... foams out to the final geometry. ... closed cells ranging in size from about 2 microns to 25 microns and having a void fraction of about 5 to 30 percent.
    Why it’s herePatent foaming a part out to its final cavity shape with closed cells of 2–25 µm.
    Cited in
    How it worksWhy we believe it
    Google Patents (opens in a new tab)PDFEspacenet
  4. 12Web page: Branson Covid Article En, emerson.com
    ultrasonic bonding uses friction and pressure to bond materials directly together... Eliminating those tiny thread holes also means eliminating more contamination potential
    Why it’s hereIndustrial ultrasonic bonding of face masks joins nonwovens without needle holes.
    Cited in
    Why we believe itWho could help
    Open source (opens in a new tab)
  5. 13Web page: Highly Focused with the Laser: From Process Development to Production Systems - Fraunhofer IPT, ipt.fraunhofer.de
    Precise cuts and weld seams can be produced with a laser spot diameter of 35 µm for laser cutting and 38 µm for laser welding.
    Why it’s hereLaser welding of thin sheets at a 38 µm spot, the feature scale the seat lattice needs.
    Cited in
    Why we believe itWho could help
    Open source (opens in a new tab)
  6. 14Web page: Polymer Processing with Supercritical Fluids, imperial.ac.uk
    Microcellular polymers have closed cells ca. 10 µm or less in diameter and a cell density of ca. 10⁸ cells/cm³
    Why it’s hereMicrocellular polymers have closed cells around 10 µm or less at high cell density.
    Cited in
    Why we believe it
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  7. 15Paper: A new core-back foam injection molding method with chemical blowing agents, Wu et al.2018
    H. Wu, G. Zhao, G. Wang and 2 moreMaterials & Design
    By combining core-back and secondary filling, a closed shell composed of dense polymer skins can be created right before melt
    Why it’s hereCore-back foam moulding forms a closed shell of dense skin, as each foam plug needs.
    Cited in
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  8. 16Paper: Static Mechanical Properties of Expanded Polypropylene Crushable Foam, Rumianek et al.2021
    P. Rumianek, T. Dobosz, R. Nowak and 2 moreMaterials
    Closed-cell expanded polypropylene (EPP) foam... compressive strength tests... for different foam densities in the range 20 g/dm³ to 220 g/dm³
    Why it’s hereCompressive behaviour of closed-cell expanded polypropylene foam across a range of densities.
    Cited in
    Why we believe it
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  9. 17Paper: Porous polymeric microparticles foamed with supercritical CO2 as scattering white pigments, Borgmann et al.2023
    L. Borgmann, S. Johnsen, C. S. d. Oliveira and 5 moreBioinspiration & Biomimetics
    Air-filled nano-scale cavities scatter broadband light, presented explicitly as 'a possible replacement for TiO₂ pigments'.
    Why it’s hereSupercritical-CO₂-foamed polymer particles scatter white light, proposed as a TiO₂ replacement.
    Cited in
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  10. 18Paper: Client Challenge
    The resemblance to amorphous structural whites in nature enables inkless printing in white and greyscale; the resolution is high enough (about 20,000 dots per inch) to generate diffractive colour.
    Why it’s hereFoaming photopolymers give pigment-free structural white at high resolution, supporting opacity carried by the foam plugs.
    Cited in
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  11. 19Web page: Non-woven laid scrim laminated with foam for reinforcement solutions, rfiber-laidscrim.com
    Due to lightweight, high strength, low shrinkage/elongation, corrosion preventive, laid scrims offers tremendous value compared to conventional material concepts.
    Why it’s hereCommercial laid scrims laminated with foam, showing foam bonded to a fibre reinforcement.
    Cited in
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  12. 20Web page: Technical Data Sheets (TDS) Per Product, olefins.net
    Tensile MD 25-85 N/5cm and CD 15-55 N/5cm as per WSP 110.4... GSM selection see GSM guide
    Why it’s hereData sheets give polypropylene spunbond tensile ranges, tested to WSP 110.4.
    Cited in
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  13. 21Web page: Influence of the calender pattern on the mechanical properties of polypropylene spunbond nonwovens, researchgate.net
    Thermally bonded polypropylene nonwovens with low basis weights between 8 and 30 g/m² play an important role in the hygiene industry
    Why it’s hereCalender pattern effects on tensile properties of light polypropylene spunbond used in hygiene.
    Cited in
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  14. 31Paper: A simple check valve for microfluidic point of care diagnostics,, Ball et al.2016
    C. Ball, R. F. Renzi, A. Priye and 1 moreLab on a Chip
    The valve's cracking pressure can be tuned by modifying the spring's planar geometry and thickness. Seal integrity is improved with the addition of a raised annular boss beneath the elastomeric pad.
    Why it’s hereMicrofluidic check valve whose cracking pressure is set by spring geometry and sealed by a raised annular seat.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
  15. 32Paper: Hydrogel Check-Valves for the Treatment of Hydrocephalic Fluid Retention with Wireless Fully-Passive Sensor for the Intracranial Pressure Measurement, Lee et al.2022
    S. Lee, S. Liu, R. Bristol and 2 moreGels
    The valves are designed to achieve a non-zero cracking pressure and no reverse flow leakage by using hydrogel swelling. The valves were evaluated in a realistic fluidic environment.
    Why it’s herePassive check valves with non-zero cracking pressure and no reverse leakage, tested in a realistic fluid setting.
    Cited in
    What we'd test
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  16. 34Paper: Microfluidic Passive Flow Regulatory Device with an Integrated Check Valve for Enhanced Flow Control, Zhang & Zhang2019
    X. Zhang and Z. ZhangMicromachines
    The prototype stopped liquid flow in the reverse mode and no liquid leakage was found in the inlet ... another prototype without the flow check valve ... showed the linearly increased back flow.
    Why it’s hereIntegrated passive check valve stopped reverse liquid flow; the valve-free control leaked increasingly.
    Cited in
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Today's approaches and closest prior art4

Today's approaches and closest prior art

4

How the field handles the problem now, and the nearest existing work.

  1. 22Patent application: Breathable disposable sanitary product construction and backsheet therefor, US 5,928,209 A1997
    Poly-Bond IncInventors: C. A. Bodford, R. C. Allen and R. K. Nayak
    A backsheet made of two SMP or SMS nonwoven fabrics with liquid-absorbent particles between them, initially hydrophobic but becoming hydrophilic when subjected to a sufficiently high hydrohead.
    Why it’s hereFilm-free backsheet whose behaviour changes once liquid pressure crosses a threshold; nearest pressure-triggered prior art.
    Cited in
    New to your fieldWho could help
    Google Patents (opens in a new tab)PDFEspacenet
  2. 23Patent application: Barrier Fabrics with Desirable Air Permeability, US 2024/0316898 A12024
    Berry Global IncInventors: L. Wang, N. Bishop, T. ZHANG and 2 more
    Each of the nonwoven layers being treated with a non-fluorinated barrier coating (NFBC) ... 45 gsm SMMMMS + NFBC at 81.2 mbar average hydrohead and 20.99 cfm, pore size 6–8 µm; outermost spunbond fibres with an average diameter from about 10 to about 25 microns, 18–22.
    Why it’s hereNearest film-free barrier: 45 gsm layered nonwoven with fluorine-free coating reaching 81.2 mbar.
    Cited in
    New to your fieldWho could help
    Google Patents (opens in a new tab)PDFEspacenet
  3. 24Patent: Breathable absorbent article, US 12,558,273 B22020
    Allegiance CorpInventors: W. H. Isaac
    hydrostatic pressure of the backsheet may be greater than or equal to 60 centimeters based on AATCC Test Method 127-2008 ... the air permeability of the underpad may range from 5 to 35 cubic feet per minute.
    Why it’s hereFilm-free breathable backsheet patent claiming at least 60 cm hydrostatic pressure with stated air permeability.
    Cited in
    New to your fieldWho could help
    Google Patents (opens in a new tab)Espacenet
  4. 25Patent: Articles containing nanofibers for use as barriers, US 9,464,369 B22005
    Procter and Gamble CoInventors: O. E. A. Isele, R. Chhabra, H. Xu and 2 more
    Mean pore diameter of less than about 15 microns… product of the hydrohead and the air permeability divided by the basis weight… greater than about 500 mbar*meter per minute per gsm.
    Cited in
    New to your field
    Google Patents (opens in a new tab)PDFEspacenet
Methods for the tests9

Methods for the tests

9

The rigs, protocols and measures the first tests borrow.

  1. 29Paper: Wetting Study of Hydrophobic Membranes via Liquid Entry Pressure Measurements with Aqueous Alcohol Solutions., García-Payo et al.2000
    M. C. García-Payo, M. A. Izquierdo-Gil and C. Fernández-PinedaJournal of Colloid and Interface Science
    Liquid entry pressure measurements with aqueous alcohol solutions of controlled surface tension.
    Why it’s hereMeasures liquid holdout pressure across a controlled surface-tension series, the rig for testing per-fluid holdout as a slope.
    Cited in
    What we'd test
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  2. 30Paper: Wetting Resistance of Commercial Membrane Distillation Membranes in Waste Streams Containing Surfactants and Oil, Eykens et al.2017
    L. Eykens, K. D. Sitter, C. Dotremont and 3 more
    The best prediction for the immediate wetting ... was obtained using the surface tension measurement combined with the contact angle of the fluid with the membrane ... long-term gradual wetting ... was not predicted by surface tension, contact angle or liquid entry pressure.
    Why it’s hereShows surface tension plus contact angle predicts immediate wetting of hydrophobic membranes, but not slow gradual wetting.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
  3. 33Paper: Advances in passive check valve piezoelectric pumps, Wu et al.2021
    X. Wu, L. He, Y. Hou and 2 more
    Taking flow rate and output pressure as comparison parameters, the characteristics of the valve, such as opening pressure and cutoff, are analyzed.
    Why it’s hereReviews how passive check valves are characterised by opening pressure and cutoff.
    Cited in
    What we'd test
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  4. 35Paper: Influence of focal spot size < 25 μm on weld seam geometry and process stability in high-precision laser micro welding, Schürmann et al.2026
    A. Schürmann, S. Backes, A. Häusler and 1 moreDiscover Mechanical Engineering
    A reduction of weld seam width is possible with this approach. However, due to heat transfer and weld pool dynamics, a reduction of spot size by 33% did not translate proportionally into seam width reduction. An increased standard deviation highlights the need for precise z-position control.
    Why it’s hereLaser micro-welding below 25 µm spot; seam width does not shrink in proportion to spot size.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
  5. 36Paper: Determination of the local three-phase morphology in laser transmission weld seams of isotactic polypropylene by Raman microscopic line-focus mapping, Braeuer et al.2026
    P. A. B. Braeuer, L. Bahr, E. Mayer and 3 morePolymer testing
    Raman microscopic line-focus mapping resolves the local three-phase morphology in laser transmission weld seams of isotactic polypropylene.
    Why it’s hereRaman mapping resolves local morphology in polypropylene laser weld seams, a way to inspect the fused seat lattice.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
  6. 37Paper: Investigation of Interfacial Microstructure and Tensile Strength of Ultrasonic Welding Joints on Nonwoven Fabrics, Nguyen et al.2020
    H. T. Nguyen, Q. Le, L. Nguyen and 2 more
    PP nonwoven density of 80 gsm ... the tensile strength of the welding joints is proportional to the area ratio between the welding area and cycling area. The results showed that the melted zone without welding defects such as crack or blowhole can be seen.
    Why it’s hereUltrasonic welds in polypropylene nonwoven show melted zones free of cracks or blowholes.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
  7. 38Paper: The measurement of the morphology of closed cell foams which control the overall thermal conductivity, Glicksman & Stewart1997
    L. Glicksman and J. Stewart
    Measurement of the morphology of closed cell foams: cell size, cell wall thickness and closed-cell content.
    Why it’s hereMeasures closed-cell foam cell size, wall thickness and closed-cell content, applicable to grown foam plugs.
    Cited in
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  8. 39Paper: Correlation between cell wall buckling and deformation banding in a closed-cell foam, Chaia et al.2019
    H. Chaia, H. Lib, X. Xiaod and 2 more
    Closed-cell foam cell-wall deformation behaviour under compression.
    Why it’s hereCharacterises closed-cell foam cell-wall buckling under compression, relevant to foam plug behaviour on its seat.
    Cited in
    What we'd test
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  9. 40Paper: Enhancement of the sound absorption of closed-cell mineral foams by perforations: Manufacturing process and model-supported adaptation, Damme et al.2024
    B. v. Damme, T. Cavalieri, C. Nguyen and 1 moreMaterials & Design
    Changing the amount of mixing water in the suspension controls the microporosity of the cell walls between 20% and 40%.
    Why it’s hereControls cell-wall microporosity in closed-cell mineral foams, a reference for checking plug skin integrity.
    Cited in
    What we'd test
    Open source (opens in a new tab)PDF
People and organizations6

People and organizations

6

The researchers, labs, companies and suppliers who could help make the idea happen.

  1. 41Paper: Plasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem - PubMed
    Name must be less than 100 characters Choose a collection: Unable to load your collection due to an error Please try again Add Cancel Permalink Display options ### Page navigation * Title & authors * Abstract * Publication types * MeSH terms * LinkOut - more resources Title & authors Abstract Publication types MeSH terms LinkOut - more resources Plant Cell Environ . 2012 Jun;35(6):1109-20. doi: 10.1111/j.1365-3040.2011.02476.x. Epub 2012 Jan 16. # Plasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem [S Jansen](https://pubmed.ncbi.nlm.nih.gov/?term=Jansen+S&cauthor_id=22220551) ¹ , [J-B Lamy](https://pubmed.ncbi.nlm.nih.gov/?term=Lamy+JB&cauthor_id=22220551) , [R Burlett](https://pubmed.ncbi.nlm.nih.gov/?term=Burlett+R&cauthor_id=22220551) , [H Cochard](https://pubmed.ncbi.nlm.nih.gov/?term=Cochard+H&cauthor_id=22220551) , [P Gasson](https://pubmed.ncbi.nlm.nih.gov/? term=Gasson+P&cauthor_id=22220551) , [S Delzon](https://pubmed.ncbi.nlm.nih.gov/?term=Delzon+S&cauthor_id=22220551) Affiliations Expand ### Affiliation * ¹ Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK. * PMID: **22220551** * DOI: [10\.1111/j.1365-3040.2011.02476.x](https://doi.org/10.1111/j.1365-3040.2011.02476.x) Free article # Plasmodesmatal pores in the torus of bordered pit membranes affect cavitation resistance of conifer xylem S Jansen et al. Plant Cell Environ . 2012 Jun . Free article Show details Display options Plant Cell Environ . 2012 Jun;35(6):1109-20. doi: 10.1111/j.1365-3040.2011.02476.x. Epub 2012 Jan 16. ### Authors [S Jansen](https://pubmed.ncbi.nlm.nih.gov/?term=Jansen+S&cauthor_id=22220551) ¹ , [J-B Lamy](https://pubmed.ncbi.nlm.nih.gov/?term=Lamy+JB&cauthor_id=22220551) , [R Burlett](https://pubmed.ncbi.nlm.nih.gov/?term=Burlett+R&cauthor_id=22220551) , [H Cochard](https://pubmed.ncbi.nlm.nih.gov/?term=Cochard+H&cauthor_id=22220551) , [P Gasson](https://pubmed.ncbi.nlm.nih.gov/?term=Gasson+P&cauthor_id=22220551) , [S Delzon](https://pubmed.ncbi.nlm.nih.gov/?term=Delzon+S&cauthor_id=22220551) ### Affiliation * ¹ Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK. * PMID: **22220551** * DOI: [10\.1111/j.1365-3040.2011.02476.x](https://doi.org/10.1111/j.1365-3040.2011.02476.x) Full text links Cite Display options ## Abstract The pit membrane in bordered pits of conifer tracheids is …
    Why it’s hereShowed that small pores through the central disc of some conifer pit membranes affect how well the valve resists air being pulled through it (air seeding).
    Cited in
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  2. 42Web page: Porous polymeric microparticles foamed with supercritical CO₂ ..., publikationen.bibliothek.kit.edu
    [KIT](https://kit.edu/) | [KIT-Bibliothek](https://www.bibliothek.kit.edu/) | [Impressum](https://www.bibliothek.kit.edu/76.php) | [Datenschutz](https://www.bibliothek.kit.edu/datenschutz.php) [KIT-Logo](https://www.kit.edu/) [KIT-Bibliothek-Logo](https://www.bibliothek.kit.edu/) [Suche im KITopen-Katalog](https://publikationen.bibliothek.kit.edu/#&recordid=KITSRCE1000155931) #### [Repository KITopen](https://www.bibliothek.kit.edu/kitopen.php) # Porous polymeric microparticles foamed with supercritical CO₂ as scattering white pigments Borgmann, Luisa Maren [ORCID iD icon](https://orcid.org/0000-0002-6665-5830) ¹ ; Johnsen, Siegbert ² ; Oliveira, Cristine, Santos de ; Martins de Souza e Silva, Juliana ; Li, Juan ³ ; Kirchlechner, Christoph ³ ,4 ; Gomard, Guillaume ¹ ,2 ; Wiegand, Gabriele ² ; Hölscher, Hendrik [ORCID iD icon](https://orcid.org/0000-0002-1033-1669) ¹ ¹ Institut für Mikrostrukturtechnik (IMT), Karlsruher Institut für Technologie (KIT) ... Such natural prototypes can be mimicked by introducing air-filled nano-scale cavities into commonly used polymers. Here, we demonstrate the foaming of initially transparent poly(methyl methacrylate) (PMMA) microspheres with non-toxic, inert, supercritical CO2. The properties of the foamed, white polymeric pigments with light scattering nano-pores are evaluated as possible replacement for TiO2 pigments. For that, the inner foam structure of the particles was imaged by phase-contrast x-ray nano-computed tomography (nano-CT), the optical properties were evaluated via spectroscopic measurements, and the mechanical stability was examined by micro compression experiments. ... mehr Open Access Logo * KITopen-Download [](https://publikationen.bibliothek.kit.edu/1000155931/151287208 "PDF Download") [Verlagsausgabe](https://publikationen.bibliothek.kit.edu/1000155931/151287208) § DOI: 10.5445/IR/1000155931/pub Veröffentlicht am 08\.09.2023 * Weitere Versionen
    Why it’s hereHis group foamed clear PMMA microspheres with supercritical CO2 into white, light-scattering particles and assessed them as a possible replacement for TiO2 pigment.
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  3. 43Patent application: Liquid barrier and air-permeable backsheet, US 2026/0009174 A12025
    Nanhai Nanxin Non Woven Co LtdInventors: D. Wu, Y. Jin, M. Fang and 1 more
    A multi-layered nonwoven backsheet design with spunbond and fine-fiber layers addresses the issue of inadequate ventilation in conventional backsheets ... to achieve both liquid barrier and air permeability, with optional surface treatments for enhanced hydrophobicity.
    Why it’s herePending patent for a layered spunbond and fine-fibre backsheet that blocks liquid and lets air through.
    Cited in
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    Google Patents (opens in a new tab)Espacenet
  4. 44Web page: Industrial foam | Cellmat Technologies, cellmattechnologies.com
    [Home](https://cellmattechnologies.com/) » About us ## About us ## CellMat Technologies # Your research partner in foams Created more than 10 years ago, in 2012, CellMat Technologies is an R&D company focused on the field of polymeric foams. The company is made up of scientists with a high level of expertise in all the different topics surrounding these materials. From the design to the production and characterization of prototypes or the modeling of their properties, we offer our partners turn-key solutions and the possibility of diving into the whole loop surrounding the development of new concepts and ideas.
    Why it’s hereAn R&D company, founded in 2012, that designs, produces and characterizes prototype polymer foams.
    Cited in
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  5. 45Web page: Trexel, linkedin.com
    Trexel Plastics Manufacturing The MuCell® microcellular foam injection molding process for thermoplastics materials provides unique design flexibility and cost savings opportunities not found in conventional injection molding. The MuCell® process allows for plastic part design with material wall thickness optimized for functionality and not for the injection molding process. The combination of density reduction and design for functionality often results in material and weight savings of more than 20%. By replacing the pack & hold phase with cell growth, lower stress parts parts are produced which have enhanced dimensional stability and substantially reduce warpage. Cell growth also results in the elimination of sink marks. Unlike chemical foaming agents, the physical MuCell® process has no temperature limitation and does not leave any chemical residue in the polymer; making consumer products perfectly suitable for recycling within the original polymer classification and allowing re-grind material to reenter the process flow. The numerous cost and processing advantages have led to rapid global deployment of the MuCell® process primarily in automotive, consumer electronics, medical parts, packaging and consume
    Why it’s hereOffers the MuCell physical microcellular foam injection-moulding process for thermoplastics, which leaves no chemical residue in the polymer.
    Cited in
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    Open source (opens in a new tab)
  6. 46Web page: NWSP 80.6 Water Resistance (Hydrostatic Pressure) » SGS-IPS Testing, ipstesting.com
    The rate of increase of the water pressure must be 10 ± 0.5 cm or 60 ± 3 cm H2O/min. Using these two different rates may give different end results. It is important to list in the test results which rate was used.
    Why it’s hereNWSP 80.6 hydrostatic test: ramp rate and support mesh change results and must be reported.
    Cited in
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Background reading60

Background reading

60

Read while building the idea; not cited in the text.

  1. 26Patent application: US4041203A - Nonwoven thermoplastic fabric - Google Patents, US 4,041,203 A
    comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary View 26 more classifications ### Landscapes Engineering & Computer Science Textile Engineering * * * ## US4041203A United States [Download PDF](https://patentimages.storage.googleapis.com/bf/f5/95/408d574c3ff626/US4041203.pdf) Find Prior Art Similar Inventor Robert J. Brock Gary H. Meitner Current Assignee Kimberly Clark Corp * * * Worldwide applications 1973 GB DE 1976 US * * * Application US05/729,356 events 1973-10-26 Priority to GB5004173A 1973-11-09 Priority to DE2356720A 1976-10-04 Application filed by Kimberly Clark Corp 1976-10-04 ... US4355066A \* 1980-12-08 1982-10-19 The Kendall Company Spot-bonded absorbent composite towel material having 60% or more of the surface area unbonded US4374888A \* 1981-09-25 1983-02-22 Kimberly-Clark Corporation Nonwoven laminate for recreation fabric US4379192A \* 1982-06-23 1983-04-05 Kimberly-Clark Corporation Impervious absorbent barrier fabric embodying films and fibrous webs US4391869A \* 1980-10-06 1983-07-05 Johnson & Johnson Baby Products Company Nonwoven fibrous product DE3331226A1 \* 1982-09-02 1984-03-08 Kimberly-Clark Corp., 54956 Neenah, Wis. WOVEN WIPE LAMINATE US4443513A \* 1982-02-24 1984-04-17 Kimberly-Clark Corporation Soft thermoplastic fiber webs and method of making US4468428A \* 1982-06-01 1984-08-28 The Procter & Gamble Company Hydrophilic microfibrous absorbent webs US4469734A \* 1981-11-24 1984-09-04 Kimberly-Clark Limited Microfibre web products US4479492A \* 1980-10-24 1984-10-30 Kimberly-Clark Corporation Bilateral split surgical drape ... Process for forming apertured nonwoven fabric prepared from melt blown microfibers US5370764A \* 1992-11-06 1994-12-06 Kimberly-Clark Corporation Apparatus for making film laminated material US5376198A \* 1987-12-22 1994-12-27 Kimberly-Clark Corporation Method for making a stretchable absorbent article EP0604736A3 \* 1992-12-28 1995-01-04 Kimberly Clark Co Polymeric strands including a propylene polymer composition and nonwoven fabric and articles made therewith. WO1995001135A1 \* 1993-06-30 1995-01-12 Kimberly-Clark Corporation Single step sterilization wrap system US5399174A \* 1993-04-06 1995-03-21 Kimberly-Clark Corporation Patterned embossed nonwoven fabric, cloth-like liquid barrier material US5409761A \* 1991-03-22 1995-04-25 Kappler Safety Group Breathable non-woven composite barrier fabric and fabrication process US5413811A \* 1994-03-18 1995-05-09 Kimberly-Clark Corporation Chemical and mechanical softening process for nonwoven web ... US5458590A \* 1993-12-20 1995-10-17 Kimberly-Clark Corporation Ink-printed, low basis weight nonwoven fibrous webs and method US5460884A \* 1994-08-25 1995-10-24 Kimberly-Clark Corporation Soft and strong thermoplastic polymer fibers and nonwoven fabric made therefrom US5464688A \* 1990-06-18 1995-11-07 Kimberly-Clark Corporation Nonwoven web laminates with improved barrier properties US5466516A \* 1990-10-15 1995-11-14 Matarah Industries, Inc. Thermoplastic fiber laminate US5482765A \* 1994-04-05 1996-01-09 Kimberly-Clark Corporation Nonwoven fabric laminate with enhanced barrier properties US5484645A \* 1991-10-30 1996-01-16 Fiberweb North America, Inc. Composite nonwoven fabric and articles produced therefrom US5490596A \* 1995-01-10 1996-02-13 Katz; Jay Autoclave bag US5492751A \* 1993-05-20 1996-02-20 Kimberly-Clark Corporation Disposable garment with improved containments means ... US5587225A \* 1995-04-27 1996-12-24 Kimberly-Clark Corporation Knit-like nonwoven composite fabric US5588155A \* 1995-03-31 1996-12-31 Kimberly-Clark Corporation Liquid impervious surgical gown cuff and method for making the same US5589249A \* 1993-01-08 1996-12-31 Poly-Bond, Inc. Medical composite with discontinuous adhesive structure US5594955A \* 1994-12-12 1997-01-21 Kimberly-Clark Corporation Surgical gown sleeve US5599420A \* 1993-04-06 1997-02-04 Kimberly-Clark Corporation Patterned embossed nonwoven fabric, cloth-like liquid barrier material and method for making same US5605739A \* 1994-02-25 1997-02-25 Kimberly-Clark Corporation Nonwoven laminates with improved peel strength US5607735A \* 1995-12-22 1997-03-04 Kimberly-Clark Corporation High efficiency dust sock US5620779A \* 1993-12-23 1997-04-15 Kimberly-Clark Corporation Ribbed clothlike nonwoven fabric US5620785A \* 1995-06-07 1997-04-15 Fiberweb North America, Inc. Meltblown barrier webs and processes of making same US5635290A \* 1994-07-18 1997-06-03 Kimberly-Clark Corporation Knit like nonwoven fabric composite US5639541A \* 1995-12-14 1997-06-17 Kimberly-Clark Corporation Oil absorbent material with superior abrasive properties US5652041A \* 1993-09-01 1997-07-29 Buerger; Gernot K. Nonwoven composite material and method for making same US5656361A \* 1996-07-23 1997-08-12 Kimberly-Clark Worldwide, Inc. Multiple application meltblown nonwoven wet wipe and method US5662978A \* 1995-09-01 1997-09-02 Kimberly-Clark Worldwide, Inc. Protective cover fabric including nonwovens US5667864A \* 1995-06-07 1997-09-16 Landoll; Leo M. Absorbant laminates and method of making same US5667562A \* 1996-04-19 1997-09-16 Kimberly-Clark Worldwide, Inc. Spunbond vacuum cleaner webs US5672415A \* 1995-11-30 1997-09-30 Kimberly-Clark Worldwide, Inc. Low density microfiber nonwoven fabric US5679042A \* 1996-04-25 1997-10-21 Kimberly-Clark Worldwide, Inc. ... US5804512A \* 1995-06-07 1998-09-08 Bba Nonwovens Simpsonville, Inc. Nonwoven laminate fabrics and processes of making same US5807366A \* 1994-12-08 1998-09-15 Milani; John Absorbent article having a particle size gradient US5810954A \* 1996-02-20 1998-09-22 Kimberly-Clark Worldwide, Inc. Method of forming a fine fiber barrier fabric with improved drape and strength of making same US5814570A \* 1994-06-27 1998-09-29 Kimberly-Clark Worldwide, Inc. Nonwoven barrier and method of making the same US5814390A \* 1995-06-30 1998-09-29 Kimberly-Clark Worldwide, Inc. Creased nonwoven web with stretch and recovery US5817584A \* 1995-12-22 1998-10-06 Kimberly-Clark Worldwide, Inc. High efficiency breathing mask fabrics US5817394A \* 1993-11-08 1998-10-06 Kimberly-Clark Corporation Fibrous laminated web and method and apparatus for making the same and absorbent articles incorporating the same US5821178A \* 1994-12-30 1998-10-13 Kimberly-Clark Worldwide, Inc. Nonwoven laminate barrier material US5822884A \* 1996-07-11 1998-10-20 Kimberly-Clark Worldwide, Inc. Slip-resistant shoe cover US5830810A \* 1995-07-19 1998-11-03 Kimberly-Clark Worldwide, Inc. Nonwoven barrier and method of making the same US5834384A \* 1995-11-28 1998-11-10 Kimberly-Clark Worldwide, Inc. Nonwoven webs with one or more surface treatments US5837352A \* 1994-12-20 1998-11-17 Kimberly-Clark Worldwide, Inc. Mechanically compatibilized film/nonwoven laminate US5841081A \* 1995-06-23 1998-11-24 Minnesota Mining And Manufacturing Company Method of attenuating sound, and acoustical insulation therefor US5843057A \* 1996-07-15 1998-12-01 Kimberly-Clark Worldwide, Inc. Film-nonwoven laminate containing an adhesively-reinforced stretch-thinned film US5853635A \* 1997-06-18 1998-12-29 Kimberly-Clark Worldwide, Inc. Method of making heteroconstituent and layered nonwoven materials US5853881A \* 1996-10-11 1998-12-29 Kimberly-Clark Worldwide, Inc. ... Pneumatic chamber having grooved walls for producing uniform nonwoven fabrics US5935512A \* 1996-12-30 1999-08-10 Kimberly-Clark Worldwide, Inc. Nonwoven process and apparatus US5939341A \* 1994-06-08 1999-08-17 Kimberly-Clark Worl
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  2. 27Patent: U.S. Patent for Method of ultrasonically bonding nonwoven webs Patent (Patent # 4,605,454 issued August 12, 1986) - Justia Patents Search, US 4,605,454
    [Justia](https://www.justia.com/) [Patents](https://patents.justia.com/) U.S. Patent for Method of ultrasonically bonding nonwoven webs Patent (Patent # 4,605,454) # Method of ultrasonically bonding nonwoven webs Jan 18, 1985 \- [Kimberly-Clark Corporation](https://patents.justia.com/assignee/kimberly-clark-corporation) Improved method of forming bonded web laminates by application of a liquid spray between the component layers prior to application of high frequency vibrational energy commonly referred to as "ultrasonic energy". The liquid is preferably water and added in a minor amount, preferably less than about 25% by weight of the combined webs. The water may be added by spraying or misting and, after bonding and drying, provides improved uniformity and web bonding while allowing increased bonding rates. ... This invention relates to methods of forming nonwoven fabrics of thermoplastic fibers by combining two or more fabric layers and ultrasonically bonding the combination. Such fabrics are normally of a heavier basis weight in the range of from 1.5 oz/yd.sup.2 (50.8 g/m.sup.2) to 9.0 oz/yd.sup.2 (305.1 g/m.sup.2), for example, and find applications requiring durability such as in recreational fabrics for tents, outer garments and similar products. These materials, when formed from thermoplastic fibers such as polyolefins, nylon, polyesters and others may be subjected to ultrasonic bonding in a patterned nip to form the desired heavier basis weight. These combined fabrics may then be further treated for water repellency or other properties depending upon the desired end use. Nonwoven materials of this nature have been marketed, for example, under the trademark EVOLUTION.RTM. by Kimberly-Clark Corporation. ... 19, 1982, discloses the use of patterned surface means with an ultrasonic horn anvil to attain lightweight pattern fuse (thermal) bonded webs. A carrier sheet is used through the bonding nip to provide improved operating speeds and reduced horn failure. It is also known to employ a bonding medium in connection with ultrasonic bonding and to apply it to webs prior to the ultrasonic bonding nip. U.S. Pat. No. 3,660,186 to Sager and Nelson dated May 2, 1972 is an example of such an arrangement. U.S. Pat. No. 4,109,353 to Mitchell and Ostermeier dated Aug. 29, 1978 is directed to ultrasonically bonding nonwoven webs, including composite layer webs, by applying water or another liquid in sufficient amounts to provide fiber mobility at the time of application of ultrasonic energy. For example, the patent suggests that water amounts in the range of at least 500% by weight and preferably at least 1300% by weight be used.
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  3. 28Web page: Nonwoven bonding patterns producing fabrics with improved strength and abrasion resistance - Kimberly-Clark Worldwide, Inc., freepatentsonline.com
    SUMMARY OF THE INVENTION The objects of the invention are met by a thermal bonding pattern for nonwoven fabric comprising a pattern having an element aspect ratio between about 2 and about 20 and an unbonded fiber aspect ratio of between about 3 and about 10. It has been unexpectedly found that such a fabric has a higher abrasion resistance and strength than a similar fabric bonded with different bond patterns. In alternative embodiments, the fabric may be perforated or apertured by stretching after bonding according to known techniques. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing of a bonding pattern satisfying the requirements of this invention and called the S-weave pattern. FIG. 2 is a drawing of a bonding pattern according to U.S. Pat. No. Login Sign up Search Application
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  4. 47Paper: Pits with aspiration explain life expectancy of a conifer species, Jansen & McAdam2019
    S. Jansen and S. McAdamProceedings of the National Academy of Sciences of the United States of America
    available evidence suggesting that torus displacement to an aspirated position requires a force below 3 µN ... the torus area that covers the pit border upon aspiration can explain variation in embolism resistance within and between species ... torus overlap is driven by variation in pit aperture area, while dimensions of the pit membrane and torus remain fairly constant.
    Why it’s hereDisc seating needs under 3 µN; disc overlap on the rim explains differences in embolism resistance.
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  5. 48Paper: The Relationships between Xylem Safety and Hydraulic Efficiency in the Cupressaceae: The Evolution of Pit Membrane Form and Function1[W][OA], Pittermann et al.2010
    J. Pittermann, B. Choat, S. Jansen and 3 morePlant Physiology
    on the one hand, cavitation resistance selects for a combination of large tori and small apertures, but on the other hand, hydraulic efficiency favors porous margos, large apertures, and small tori ... Calculations of margo strain at aspiration based on measurements of membrane and torus diameter suggest that deformation of the margo is decoupled from the cavitation pressure.
    Why it’s hereShows the trade-off in conifer pits: large discs and small apertures for safety, open meshes for flow.
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  6. 49Paper: New Insights into the Mechanisms of Water-Stress-Induced Cavitation in Conifers, Cochard et al.2009
    H. Cochard, T. Hölttä, S. Herbette and 2 morePlant Physiology
    we found a linear relation between sample vulnerability to cavitation and fluid surface tension. This suggests that cavitation in conifers could also be provoked by the capillary failure of an air-water meniscus in coherence with the prediction of Young-Laplace's equation.
    Why it’s hereConifer vulnerability tracks fluid surface tension linearly, following the Young–Laplace capillary prediction.
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  7. 50Paper: Size and function in conifer tracheids and angiosperm vessels., Sperry et al.2006
    J. Sperry, U. G. Hacke and J. PittermannAmerican-Eurasian journal of botany
    The differences in air-seeding pressure between species are predicted to be a function of the number of margo strands holding the torus in place and their mechanical properties (Hacke et al., 2004).
    Why it’s herePredicts air-entry pressure from the number and stiffness of mesh strands holding the conifer disc.
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  8. 51Web page: Different hypotheses of air-seeding through a conifer bordered pit..., researchgate.net
    (a) margo capillary-seeding ... (b) margo stretch-seeding ... (c) seal capillary-seeding ... (d) margo rupture-seeding, by membrane breakage.
    Why it’s hereSets out four ways air can leak through a conifer bordered pit valve, including leakage at the seal.
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  9. 52Paper: Geometrical and physicochemical considerations of the pit membrane in relation to air seeding: the pit membrane as a capillary valve., Meyra et al.2007
    A. Meyra, V. A. Kuz and G. J. ZarragoicoecheaTree Physiology
    Pit membrane structure, viewed as a three-dimensional mesh of intercrossing fibrils, and vulnerability to water-stress-induced air seeding are examined in the context of the Young-Laplace equation.
    Why it’s hereTreats the pit membrane as a capillary valve analysed with the Young–Laplace equation.
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  10. 53Paper: Consistent decrease in conifer embolism resistance from the stem apex to base resulting from axial trends in tracheid and pit traits, Zambonini et al.2023
    D. Zambonini, T. Savi, S. Rosner and 1 morebioRxiv
    In conifers, when a gas bubble expands and embolizes a tracheid, the pit membranes get aspirated towards the functional conduit due to the pressure difference ... The margo flexibility and the ratio of torus to pit aperture diameter (i.e., the torus overlap) contribute to a valve effect that seals the pit aperture of the functional tracheid when neighboring tracheids become embolized.
    Why it’s hereMesh flexibility and disc-to-aperture ratio together give the conifer pit its valve effect.
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  11. 54Paper: The Fluid–Solid Interaction in the Nonlinear Pressure–Flux Relationship of Bordered Pits in Oriental Arborvitae (Platycladus orientalis), Xia et al.2024
    P. Xia, Y. Wu, W. Song and 4 moreForests
    The deflection of the torus was roughly proportional to the pressure difference between adjacent tracheids, while the pit resistance exhibited a considerable nonlinear increase.
    Why it’s hereDisc deflection scales with pressure while pit flow resistance rises nonlinearly as the valve closes.
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  12. 55Paper: Rheological and interfacial characterization of menstrual fluid, Pero et al.2026
    E. Pero, C. Neu, A. Wolf and 3 moreThe Physics of Fluids
    Menstrual fluid viscosity is approximately fourfold higher than blood and forty-fold higher than water … Surface tension is significantly lower than that of water and comparable to that of venous blood … Current industrial simulants are typically simplified water- or blood-like fluids that may not adequately reproduce the complex behavior of real menses.
    Why it’s hereReal menses has lower surface tension than water and is far more viscous, so water tests over-predict holdout.
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  13. 56Web page: NWSP 402.0 Cup Crush » SGS-IPS Testing, ipstesting.com
    The material must have sufficient structural integrity to be formed into the cup shape and then be able to maintain that shape until it is tested. ... A 225-mm square specimen ... A 44.5 mm diameter hemispherical-shaped plunger
    Why it’s hereDefines the NWSP 402.0 cup crush softness test: specimen size and plunger.
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  14. 57Patent application: Mechanical and internal softening for nonwoven web, US 5,770,531 A1996
    Kimberly Clark Worldwide IncInventors: G. T. Sudduth and A. Yahiaoui
    An absolute cup crush load value of about 70 grams or less is considered desirably soft for the purposes of this invention.
    Why it’s hereEarlier nonwoven patent rating cup crush of about 70 g or less as desirably soft.
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  15. 58Web page: Per- and polyfluoroalkyl substances (PFAS) - ECHA, echa.europa.eu
    ECHA supports PFAS restriction with targeted derogations, 26 March 2026; updated restriction proposal published 20 August 2025; risk assessment committee opinion adopted 3 March 2026; textiles among the sectors evaluated.
    Why it’s hereEU universal PFAS restriction timeline, with textiles among the sectors under evaluation.
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  16. 59Web page: Nonwoven Fabric for Surgical Gowns: SMS & SMMS Guide, olefins.net
    Level 2 | AATCC 42 + AATCC 127 (≥20 cm H₂O) | SMS nonwoven | 25–45 GSM ... Level 3 | AATCC 42 + AATCC 127 (≥50 cm H₂O) | SMS / SMMS | 35–55 GSM
    Why it’s hereCommodity SMS/SMMS barrier levels: about 49 mbar at 35–55 gsm, below the 62 mbar requirement.
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  17. 60Web page: DuPont Tyvek StuccoWrap, constructioninstruction.com
    ASTM E2178: .004 cfm/ft² @1.57 psf; Gurley Hill: >300 sec/100cc; ASTM E96-00 Method A: 250 g/m²/24 hrs, Method B: 350; AATCC 127: 210 cm.
    Why it’s hereFlash-spun sheet data: very high water holdout but very low air permeability.
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  18. 61Paper: Laser Transmission Welding of Polypropylene: Insights into Parameter Interplay, Thermal Analysis, Bonding Quality, Fracture Characteristics, and Weld Morphology, Anwer & Acherjee2024
    G. Anwer and B. AcherjeeJournal of materials engineering and performance (Print)
    Laser transmission welding (LTW), a versatile polymer joining process utilizing laser energy, and its application to polypropylene...
    Why it’s hereLaser transmission welding of polypropylene: how process parameters set bond quality and weld morphology.
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  19. 62Paper: Laser Transmission Welding of Semi-Crystalline Polymers and Their Composites: A Critical Review, Dave et al.2021
    F. Dave, M. Ali, R. Sherlock and 2 more
    LTW has been known for high precision manufacturing and polymer processing of complicated and micro geometries
    Why it’s hereReview: laser transmission welding handles micro geometries in semi-crystalline polymers.
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  20. 63Web page: Polypropylene Foam Data Sheet, foambymail.com
    Expanded Polypropylene Foam (EPP) is a rigid closed-cell foam with great compression and impact resistance... Compressive Strength @ 10%: 11.7 psi (1.3 lb/ft³)
    Why it’s hereData sheet giving compressive strength of closed-cell expanded polypropylene foam.
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  21. 64Paper: Analysis of the foam-forming of non-woven lightweight fibrous materials using X-ray tomography, Burke et al.2021
    S. R. Burke, M. E. Möbius, T. Hjelt and 2 moreSN Applied Sciences
    Through image analysis and uniaxial compression testing, we find that the orientation of the fibres, rather than the size of the voids, determine the compressive strength of the material.
    Why it’s hereFoam-formed fibrous materials: fibre orientation, not void size, sets compressive strength.
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  22. 65Web page: Microscopic foam gives polymers pigment-free whiteness and water repellency, nanowerk.com
    foamed structures made mostly of air scatter light with extraordinary efficiency, creating intense whiteness without the need for pigments
    Why it’s hereReports that microscopic polymer foams give strong whiteness without pigment.
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  23. 66Web page: Foam Mie | Foam-Tech | Prof Steven Abbott, stevenabbott.co.uk
    The scattering from features of typical dimension φ at wavelength λ can be approximated by Mie theory. The scattering depends on the refractive index, n solid, of the cell material... compared to the air
    Why it’s hereMie-theory account of light scattering by foam cells, set by refractive-index contrast with air.
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  24. 67Paper: Preparation and Applications of Electrospun Optically Transparent Fibrous Membrane, Xiao et al.2021
    Y. Xiao, H. Luo, R. Tang and 1 morePolymers
    Transmittance falls as areal density rises; the web dense enough to be opaque is the web that is stiff and low-permeability.
    Why it’s hereIn nanofibre webs, opacity comes only with higher areal density, tying opacity to stiffness.
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  25. 68Web page: Medical Nonwoven Fabric Supplier, olefins.net
    SMMS — High Barrier | 40-60 GSM | Level 3-4 | ≥50 cm H₂O + Blood/Viral barrier for L4
    Why it’s hereHigh-barrier SMMS at 40–60 gsm rated about 50 cm water.
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  26. 69Web page: DuPont Tyvek Technical User Guide, dupont.com
    Untreated Tyvek B styles exceed 50 in H2O = 127 cm H2O ≈ 125 mbar average hydrostatic head; WVTR 250–350 g/m²/24 h; air-leakage rate 0.004 cfm/ft² @ 1.57 psf; Gurley >300 s/100 cc.
    Why it’s hereFlash-spun sheets about 125 mbar water holdout, with very low air leakage.
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  27. 70Web page: Standard Test Method for Air Permeability of Textile Fabrics, astm.org
    Standard Test Method for Air Permeability of Textile Fabrics, ASTM Committee D13.
    Why it’s hereASTM D737 standard method for air permeability of fabrics.
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  28. 71Web page: Tensile Strength Standards for Spunbond Nonwoven Fabrics, ecologynonwoven.com
    N/50mm and N/5cm are commonly used measurement units
    Why it’s hereExplains the N/50 mm units used for spunbond tensile strength.
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  29. 72Web page: Critical Surface Tension and Contact Angle with Water for Various Polymers (sort by contact angle), accudynetest.com
    This table compares critical surface tension to contact angle with water for a variety of polymers.
    Why it’s hereTable of polymer critical surface tension and water contact angle, used in the seat capillary estimates.
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  30. 73Paper: Tetrapodal textured Janus textiles for accessible menstrual health, Sanders et al.2023
    S. L. Sanders, L. D. Douglas, T. E. Sill and 5 moreiScience
    Wetback was ~8× higher with menses simulant (217 ± 87 mg) than saline (27 ± 7 mg), attributed to the lower surface tension 'decreas[ing] the capillary resistance'.
    Why it’s hereMenses simulant gave about 8× the wetback of saline, blamed on lower capillary resistance.
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  31. 74Paper: Compressive behavior and deformation mechanisms of rigid polymeric foams: A review, Rahimidehgolan & Altenhof2023
    F. Rahimidehgolan and W. AltenhofComposites Part B: Engineering
    Foam response includes cell-edge bending and cell-face stretching; the modulus relation contains edge fraction, proportionality constants and internal gas pressure.
    Why it’s hereReview of rigid foam compression mechanisms, informing the plug-resilience estimate.
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  32. 75Web page: Liquid entry pressure - Wikipedia, en.wikipedia.org
    The liquid-entry-pressure expression includes a minus sign multiplying the cosine of the liquid-side contact angle.
    Why it’s hereLiquid entry pressure relation with its sign on the contact-angle term, used for the residual-gap estimate.
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  33. 76Web page: Height Parameters, physics.nist.gov
    Ra is arithmetic mean deviation; maximum peak, valley and total profile heights are separate parameters.
    Why it’s hereDefines surface roughness height parameters, used for sizing the residual channel at the seat.
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  34. 77Web page: Expanded Polypropylene Datasheet, thefoamfactory.com
    Expanded Polypropylene Foam (EPP) is a rigid closed-cell foam ... Density: 1.3 lb/cubic ft; white range 1.5–2.8 lb/cubic ft.
    Why it’s hereData sheet giving density range of closed-cell expanded polypropylene foam.
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  35. 78Paper: Foaming photopolymers as a high-resolution biomimetic printing platform, Qin et al.2026
    D. Qin, X. Liu, B. Kuang and 5 moreNature
    Deep-foam photolithography is applied to both films and fibres ... Patterning µm-level spatial differences in foamability, wettability, optical properties and local thickness.
    Why it’s hereDeep-foam photolithography patterns foaming at micron scale on both films and fibres.
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  36. 79Web page: Standard Test Methods for Gravimetric Determination of Water Vapor Transmission Rate of Materials, astm.org
    A WVTR result obtained in one method under one set of test conditions cannot be used to predict the result … with a different set of conditions, or using the other method.
    Why it’s hereASTM E96 vapour transmission methods; results do not transfer across methods or conditions.
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  37. 80Web page: DUPONT TYVEK 1443R, plastma.com.mx
    Basis weight 43 [41–45] g/m²; tensile MD 49 and CD 48 N/2.54 cm; elongation MD 11%, CD 20%. Tensile method modified for speed and gauge length.
    Why it’s hereFlash-spun sheet properties: basis weight, tensile strength and elongation.
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  38. 81Paper: CFD-based genetic programming model for liquid entry pressure estimation of hydrophobic membranes, Chamani et al.2020
    H. Chamani, P. Yazgan-Birgi, T. Matsuura and 4 more
    This work provides an explicit formula for estimation of LEP in a closer agreement with the experimental data in comparison to the Young-Laplace equation.
    Why it’s hereCFD-based formula for liquid holdout pressure of hydrophobic membranes, a better fit than Young–Laplace.
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  39. 82Paper: Fabrication of bio-mimetic multi-voided polystyrene particles acting as broad-band light scatterers, Bianco2017
    A. Bianco
    Multi-voided polystyrene particles acting as broad-band light scatterers.
    Why it’s hereMulti-voided polystyrene particles act as broadband light scatterers.
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  40. 83Paper: Morphological evolution of PLA foam from microcellular to nanocellular induced by cold crystallization assisted by supercritical CO2, Ni et al.2020
    J. Ni, K. Yu, H. Zhou and 3 more
    A nanocellular foam with a cell density of 1015 cells/cm3 and a cell size of approximately 30 nm was obtained.
    Why it’s hereSupercritical CO₂ foaming reached cells of about 30 nm at very high cell density.
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  41. 84Paper: Integrating Hollow Metal‐Organic Frameworks with Supercritical CO2: A Path to High‐Performance Polystyrene Microcellular Foams, Wang et al.2025
    W. Wang, H. Guo, Y. Ding and 4 moreAdvanced Engineering Materials
    incorporating HZIF-8 into PS significantly increases the cell density (up to 1.4 × 109 cells cm−3) and decreases the average cell size (to 8.6 μm)
    Why it’s hereAdditive-assisted CO₂ foaming of polystyrene gave 8.6 µm cells at high density.
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  42. 85Paper: In Situ Dispersion of Lignin in Polypropylene via Supercritical CO2 Extrusion Foaming: Effects of Lignin on Cell Nucleation and Foam Compression Properties, Ho et al.2023
    K. Ho, X. Lu and S. K. LauPolymers
    The plateau compression strength of closed-cell foam is measured in the relatively levelled region of the compression curve, in which the deformation is mainly caused by plastic buckling of the cell walls.
    Why it’s hereClosed-cell foam compressive plateau arises from plastic buckling of the cell walls.
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  43. 86Paper: Anisotropic compressive behavior of rigid PVC foam at strain rates up to 200 s−1, Liu et al.2020
    Y. Liu, F. Rahimidehgolan and W. Altenhof
    Except for the lowest density of 45 kg/m3, strain rate effects were clearly observed through increased compressive strength and plateau stress when loading in the foam rise direction.
    Why it’s hereRigid PVC foam plateau stress rises with strain rate for most of the densities tested.
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  44. 87Paper: Structure-properties relationships of cellular materials from biobased polyurethane foams, Peyrton & Avérous2021
    J. Peyrton and L. AvérousMaterials science & engineering. R, Reports
    Two main types of foam can be fabricated: (i) flexible with open cells ... and (ii) rigid with closed cells, low thermal conductivity, low density and high dimensional stability.
    Why it’s hereContrasts flexible open-cell foams with rigid, low-density closed-cell foams.
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  45. 88Patent application: Fabrics including a non-fluorinated barrier coating, US 2024/0183104 A12023
    Berry Global IncInventors: L. Wang and N. Bishop
    The fabrics may provide the same or improved barrier properties as fabrics treated with fluoro-chemicals despite being devoid of fluorine atoms.
    Why it’s hereFluorine-free coated fabrics claimed to match fluorochemical barrier performance.
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  46. 89Web page: Fluorine-free hydrophobic and oleophobic nonwoven, eureka.patsnap.com
    A nonwoven fabric is treated with an aqueous colloidal solution containing nanoscale SiO2-particles ... to achieve hydrophobic and oleophobic properties, with a surface tension lower than 24 mN/m.
    Why it’s hereFluorine-free silica finish makes nonwovens repel water and oil, below 24 mN/m.
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  47. 90Paper: Fluorine-free hydrophobic powder coatings: a sustainable approach using functionalized biogenic SiO2 for anticorrosion and antifouling applications, Nazarlou et al.2025
    Z. Nazarlou, H. Najjari, A. Olad and 1 moreSurfaces and Interfaces
    The incorporation of silane-functionalized biogenic SiO₂ nanoparticles produced hydrophobic surfaces, with the highest CA of 144° achieved at a 20 wt. % HTMS-SiO₂ loading.
    Why it’s hereFluorine-free silica-based coatings reach 144° water contact angle.
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  48. 91Web page: ECHA Backs EU-Wide PFAS Restriction with Targeted Derogations - REACH24H, en.reach24h.com
    Both of its scientific committees—RAC and SEAC—expressed support for the implementation of EU-wide comprehensive restrictions on PFAS while explicitly stating that targeted derogations will be introduced.
    Why it’s hereECHA committees support an EU-wide PFAS restriction with targeted derogations.
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  49. 92Web page: Per- and polyfluoroalkyl substances (PFAS), europarl.europa.eu
    The European Chemicals Agency is expected to transmit its final opinion to the European Commission by the end of 2026.
    Why it’s hereEU briefing: final ECHA PFAS opinion expected by the end of 2026.
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  50. 93Patent: Chemical and mechanical softening process for nonwoven web, EP 0 672 777 B11995
    Kimberly Clark Worldwide IncInventors: S. W. Fitting, J. J. Sayovitz, J. E. Edwards and 1 more
    The present invention provides a method of producing a soft nonwoven web having a softness corresponding to a cup crush value of 70 g or less.
    Why it’s hereSoftening-process patent targeting nonwovens with cup crush of 70 g or less.
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  51. 94Web page: NWSP 80.6 Water Resistance (Hydrostatic Pressure) Test, eurolab.net
    Rate of increase of water pressure should be 10 ± 0.5 or 60 ± 3 cm H2O/min; using these two ratios can yield different results... A nylon mesh or mesh screen is sometimes used to support the sample... If this technique is used, it should be reported with the test results.
    Why it’s hereSame NWSP 80.6 requirements on ramp rate and support-mesh reporting, from a second source.
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  52. 95Web page: INDA, Association of the Nonwoven Fabrics Industry - Cary, NC - Test Method Approach, inda.org
    It is important to emphasize that there is no standard 'synthetic urine,' because th...
    Why it’s hereNonwovens industry body notes there is no standard synthetic urine.
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  53. 96Web page: Absorbent Hygiene Product Stewardship Programme test methods| EDANA, edana.org
    The next step of the overall method is that a specimen of the milled, homogenized sample is extracted in an excess of extraction liquid ... aqueous solutions that mimic urine and menses as the extraction fluid.
    Why it’s hereHygiene test methods use aqueous fluids that mimic urine and menses.
    Open source (opens in a new tab)
  54. 97Web page: ASTM & ISO Test Methods for Measureing Properties, dupont.co.uk
    The reference standards are AATCC TM 127 and EN 20811, with rate of use set at 60 cm H2O/min.
    Why it’s hereHydrostatic head measured to AATCC 127 / EN 20811 at 60 cm water per minute.
    Open source (opens in a new tab)
  55. 98Web page: Standard Test Method for Air Permeability of Textile Fabrics, astm.org
    Air permeability ... can be used to provide an indication of the breathability of weather-resistant and rainproof fabrics.
    Why it’s hereASTM D737 air permeability as a measure of fabric breathability.
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  56. 99Paper: Assessing the seam strength of ultrasonically welded polyester and polypropylene spunbond nonwovens, Çi̇nçi̇k & Üstün2022
    E. Çi̇nçi̇k and A. İ. ÜstünJournal of Industrial Textiles
    the water-resistance property of the joining of 45 gr/m² SMMS and 50 gr/m² SMS fabric types with the flat roller ... showed a better performance than any other alternatives
    Why it’s hereUltrasonically welded SMMS/SMS seams kept water resistance best with a flat roller.
    Open source (opens in a new tab)PDF
  57. 100Paper: Laser transmission welding of polymers – A review on welding parameters, quality attributes, process monitoring, and applications, Acherjee2021
    B. Acherjee
    Cross-section micrographs of microtome-cut PP (polypropylene) weld specimens with various welding seam conditions.
    Why it’s hereReview of laser transmission welding with cross-sections of polypropylene weld seams.
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  58. 101Paper: Capillary Characterization of Fibrous Reinforcement and Optimization of Injection Strategy in Resin Transfer Molding, Causse et al.2018
    P. Causse, C. Ravey and F. Trochu
    The position of the capillary flow front was then used to deduce the optimal impregnation velocity range based on the Lucas-Washburn flow model.
    Why it’s hereLucas–Washburn capillary flow-front data used to set impregnation speed of fibrous reinforcement.
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  59. 102Patent application: Barrier fabrics with desirable air permeability, US 2025/0295532 A12025
    Nanhai Nanxin Non Woven Co LtdInventors: L. Wang, N. Bishop, T. ZHANG and 2 more
    Each of the nonwoven layers being treated with a non-fluorinated barrier coating (NFBC).
    Why it’s hereRelated application: fluorine-free coated nonwoven barrier fabrics with good air permeability.
    Google Patents (opens in a new tab)Espacenet
  60. 103Web page: Non Woven Fabric Price Trend 2026, Forecast, News, Chart, expertmarketresearch.com
    Global non woven fabric prices tracked close to the USD 1.74 to USD 1.92 per KG range projected for 2026.
    Why it’s hereNonwoven fabric price range projected for 2026, about USD 1.74–1.92 per kg.
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