Custom Wearable & On-Body Electronics Layers: Skin Adhesives, Gaskets, Vent & Acoustic Membranes
H-O Products die-cuts and converts the thin layers a worn device lives on: skin-contact acrylic and silicone gel adhesives, sensor and display cushions, closed-cell perimeter sweat seals, ePTFE vent membranes, and small acoustic mesh gaskets, built to your drawing.
Skin-contact adhesives are supplied per the vendor TDS with biocompatibility data per ISO 10993 available from the material maker; the biocompatibility evaluation belongs to the finished device and its maker, and any IP or water rating belongs to the complete tested device, not to a single gasket.
Built for: patches and continuous monitors, smart watches and bands, on-body pods and hearables — die-cut skin adhesive rings, optical-sensor and display cushions, sweat/splash perimeter gaskets, breathable moisture-vapor paths, internal spacer and stack layers, and mic/speaker acoustic mesh vents.
To spec the layers for a wearable, read the stack from the skin outward. Skin interface: a silicone gel for gentle, low-trauma removal or a gentle acrylic PSA for longer wear and higher hold — chosen by wear time, with ISO 10993 biocompatibility data from the maker. Moisture-vapor path: a breathable pattern plus a ePTFE vent membrane — an occlusive layer with no vapor path macerates skin and lifts.
Perimeter sweat seal: closed-cell silicone foam compressed into its window. Sensor cushions (PORON® microcellular PU) and acoustic parts (acoustic mesh) are mapped in the When-to-spec list. Values are per the TDS on file; see the material reference below for ordering details.
ISO 10993 · IEC 60529 · ASTM D3574 · ASTM D1056 · ASTM D395 · ASTM D2240 · ASTM D3330 · UL 94
Cited by designation, per the maker TDS: ISO 10993 (biocompatibility, the device/maker's evaluation) · IEC 60529 (IP code, on the complete device) · ASTM D3574 (cellular urethane) · ASTM D1056 (cellular rubber) · ASTM D395 (compression set) · ASTM D2240 (durometer) · ASTM D3330 (PSA peel) · UL 94 (flammability class where a pod battery requires it).
- Gentle, low-trauma skin adhesive: silicone gel PSA / silicone-acrylic combination
- Longer wear, higher hold skin adhesive: skin-contact acrylic PSA
- Sensor / display cushion & spacer: PORON® microcellular PU
- Perimeter sweat/splash gasket: closed-cell silicone foam / EPDM foam
- Breathable / vent path: ePTFE vent membrane
- Mic/speaker acoustic mesh: acoustic mesh / vent + reticulated PU
- Thin spacer / stack & light-block film: XLPE foam / Kapton® / PET film
- Device-side bonding tape: acrylic transfer / double-coated tape
Where are you in the on-body spec?
This page serves engineers who already know the layer they want and engineers still working out the whole on-body stack. Pick the path that matches where you are; you don't have to read the rest.
Send a drawing, get a quote
A skin-contact adhesive ring, an optical-sensor cushion, a closed-cell perimeter sweat seal, an ePTFE vent, an acoustic mesh gasket, or a kit for the whole on-body stack, on your drawing.
Skip to the quote form →Build the on-body stack requirement by requirement
Six selection factors (skin interface, moisture-vapor path, perimeter sealing, cushion/spacer, repeated flex and washability, acoustic and vent openings), a stack builder, and a family-by-family comparison with TDS-cited methods.
Start with selection factors →
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1Send drawingUpload a DXF, STEP, or PDF, or describe the patch, watch back, or pod and its layers. A sample part works too.
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2On-body reviewEngineering reviews the skin footprint and wear time, the moisture-vapor path, the perimeter sealing window, the sensor and display cushions, and the mic/speaker openings against the maker TDSs, including the adhesive maker's ISO 10993 biocompatibility data for any skin-contact layer.
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3PrototypeSamples typically ship in 3–5 business days for common configurations on materials we keep on hand. Made-to-order; MOQ varies by material and part.
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4ProductionStandard production runs ship about 2 weeks after drawing approval, on flatbed die-cutting, CNC knife cutting for kiss-cut layer sets, and kitting for the whole on-body stack. Ongoing parts run with material traceability and lot-code TDS records.
This guide is for hardware, mechanical, and industrial-design engineers specifying layers for worn devices: patches and continuous monitors, smart watches and bands, on-body pods, and hearables. It covers skin-contact adhesives, sensor and display cushions, perimeter sweat seals, breathable and acoustic membranes, and internal spacer/stack layers.
It is also for the sourcing buyer qualifying a made-to-order converted layer against a maker TDS, the adhesive maker's ISO 10993 biocompatibility data, and lot traceability — noting that H-O is an ISO 9001:2015 certified organization and does not certify biocompatibility or make a medical claim.
On-body device → define the skin interface and openings → select each layer → and kit → production supply.
- 1Define the stackSkin footprint and wear time, moisture-vapor need, perimeter sealing window, sensor/display geometry, mic/speaker ports.
- 2Set the skin interfaceSilicone gel vs gentle acrylic by wear time and trauma, with the maker's ISO 10993 data on file.
- 3Pick each layerCushion, spacer, closed-cell perimeter gasket, ePTFE vent, acoustic mesh — each to its method.
- 4Add liner, PSA, pull tabAdhesive side, protective liner, and pull tabs specified for line assembly.
- 5Die-cut to drawingOutline, holes, keep-outs, and kiss-cut sets cut to the footprint and tolerance.
- 6Quote prototype or productionSample quantities through full production runs, with TDS and lot-code records.
Which on-body layer are you solving?
Application Zones
Six layers define a worn device, read from the skin outward: the skin-contact adhesive that holds the device to the body for a defined wear time; the optical-sensor window and cushion that set the sensor-to-skin gap; the display cushion and perimeter sweat seal; the breathable moisture-vapor path that keeps skin from macerating; the internal spacer and stack layers that locate components; and the mic/speaker acoustic mesh and vent. Click a tab to see the stack, the controlling property, and the families H-O converts for that zone.
Skin-contact adhesive: hold, wear time, and clean release
At the skin sits the PSA ring or patch that holds a monitor, patch, or pod to the body for a defined wear time and then releases without stripping skin. Two chemistries cover most of the work. A silicone gel adhesive is gentle, repositionable, and low-trauma on removal, suited to sensitive skin and shorter wear; a gentle acrylic starts low and builds hold over time, reaching longer multi-day wear at the cost of more removal trauma.
Wear time runs from short-term (about a day) to long-term (multi-day or weeks), stated per the maker TDS — H-O does not invent skin-panel numbers. Adhesive selection is a system decision (substrate, surface energy, temperature, exposure, dwell, pressure, prep, geometry, assembly), and the skin-contact call adds one more axis: biocompatibility data per the ISO 10993 series comes from the adhesive maker, and the wear-safety and sensitization judgment belongs to the device maker.
Send the skin footprint and target wear time with your drawing so the right chemistry is chosen first. [7] [6]
Optical sensor window & cushion: set the gap, block stray light
A PPG or optical heart-rate window needs a thin spacer that sets the sensor-to-skin gap and blocks stray light from crossing between the emitter and the detector. Get the gap wrong or let light leak around the window and the reading drifts.
Thin microcellular PU (PORON® family, cut into the sub-millimetre range some grades support) gives a light, low-compression-set cushion that both sets the gap and protects the sensor package under the flex and impact of a worn device; a thin PET or polyimide light-block film rings the window where an opaque mask is needed.
Compression-set resistance is the long game: the cushion has to hold its deflection over the wear life. [11]
Display cushion & perimeter sweat seal: compress into the window
The cover lens and the housing seam both need protection from sweat and splash. A thin closed-cell silicone-foam or PU perimeter gasket compressed into its sealing window seals the seam between the two housing halves against sweat and hand-washing, and a thin cushion frame protects the cover lens against the bezel. The honesty rule governs here: a closed-cell gasket seals by construction, but the water or immersion rating belongs to the complete tested device measured per IEC 60529, not to the gasket alone.
Closed-cell silicone holds up across a wide temperature range with low compression set; an EPDM foam is an economical perimeter alternative where its temperature and media exposure suit the housing. An acrylic transfer tape bonds the cover lens where a compressed gasket is not the answer. Give the sealing window dimensions and the target immersion, and let the tested device carry the rating. [12] [1]
Breathable / moisture-vapor path: let the skin transpire
Skin under an occlusive layer transpires, and a device that traps that moisture macerates skin and lifts the patch. A comfortable long-wear device needs a moisture-vapor path: a breathable adhesive pattern (perforation or zones) and, where the housing is otherwise sealed, an ePTFE vent membrane that passes moisture vapor while blocking liquid water.
Worn devices show moisture-vapor transmission roughly in the 600–1,400 g/m²/day range at room temperature, with vapor-permeable fabrics far higher (about 3,500–3,600) and conductive hydrogels higher still (about 4,000–5,000), stated as device-patent ranges per the maker method — verify per your design.
The vent membrane does double duty: it equalizes pressure across temperature and immersion cycles and keeps sweat and water out while the vapor path stays open. [9] [10]
Internal spacer / stack layers: set gaps, locate components
Inside a patch or pod, thin shims set the gaps and locate the components: the board, the battery, the sensor, the antenna. Thin PU or PE foam gives light cushioning and gap-set shims; a film locates or insulates a layer where a foam would be too thick. These are the least glamorous layers and the ones that decide whether a stack goes together right the first time.
Because they are thin and geometry-driven, the drawing note is the thickness and the location tolerance, not a material headline. A double-coated tape laminates the stack together where a bond is wanted between layers. Kit the whole stack on one liner in assembly order and the line builds it faster.
Mic / speaker acoustic mesh + vent: pass sound, block water
A mic or speaker port on a worn device floods or clogs without protection. A small acoustic mesh with an adhesive ring sits over the port and passes sound while blocking water and dust to a stated immersion depth per the vendor TDS (for example, waterproof to a stated depth such as 30 m on some portable/wearable acoustic grades).
Reticulated PU behind the mesh damps and filters where the acoustic design calls for it. As with every opening on this page, the immersion figure is the membrane maker's stated grade rating; the device's overall IP rating is measured on the complete tested unit per IEC 60529. [10]
Six decisions that drive your on-body stack
A worn device is a stack of single-purpose layers, and each has one controlling property. The failures here are personal and quiet: a skin adhesive too aggressive strips skin on removal, an occlusive layer macerates skin over a day of wear, or a perimeter gasket leaks sweat into a device that read fine on the bench.
Two honesty rules govern the whole stack. Biocompatibility for skin-contact parts is evaluated per the ISO 10993 series, and that evaluation belongs to the finished device and its adhesive maker — H-O supplies the converted layer and passes through the maker's data and lot traceability, and makes no medical or certification claim. And any IP or water rating belongs to the complete tested device measured per IEC 60529, not to any one gasket, vent, or mesh. Put the wear time, the skin footprint, and the immersion target on the drawing.
Skin-contact adhesives carry biocompatibility data per the ISO 10993 series — evaluation (-1), cytotoxicity (-5), irritation and skin sensitization (-10), systemic toxicity (-11) — from the adhesive maker. H-O the converted skin-contact layer and passes through the maker's TDS and lot-code records; the biocompatibility and wear-safety judgment is the device manufacturer's. H-O is an ISO 9001:2015 certified organization and makes no ISO 13485, FDA, or medical claim. [2] [3]
Read the six factors below in order. The first frames the skin interface (wear time and trauma), the second the moisture-vapor path, the third the perimeter seal; the next two size the cushions and set the flex and washability duty; the last handles the acoustic and vent openings. Every factor names its method, because on this page the skin-adhesive value is meaningful only with its test conditions and its maker's ISO 10993 data attached.
Show all 6 selection factors tap to expand
Skin interface: wear time and removal trauma
Rule — choose the skin adhesive by wear time and removal trauma, with the maker's ISO 10993 data on file. A silicone gel is gentle, repositionable, and low-trauma but holds less; a gentle acrylic starts low, builds over time, and reaches longer multi-day wear at the cost of more removal trauma.
Adhesive selection is a system decision (substrate, surface energy, temperature, exposure, dwell, pressure, prep, geometry, assembly), and the skin-contact call adds biocompatibility: the ISO 10993 series data comes from the adhesive maker, not from H-O.
State the target wear time and the skin footprint so the chemistry is chosen first. [7] [2]
Moisture-vapor path: breathability against maceration
Rule — give the skin a moisture-vapor path, because an occlusive adhesive or gasket with no breathable route traps sweat, macerates skin, and lifts the patch. A breathable adhesive pattern (perforation or zones) plus an ePTFE vent membrane is the fix, and MVTR is the number — worn devices run roughly 600–1,400 g/m²/day at room temperature, higher for vapor-permeable fabrics and hydrogels, stated as device-patent ranges per the maker method. State the wear duration and comfort target so the breathable path is designed in. [9] [8]
Perimeter sealing: closed-cell into its window
Rule — seal the housing seam with a closed-cell perimeter gasket compressed into its sealing window, and remember that the water rating belongs to the tested device. A closed-cell silicone or PU gasket seals sweat and splash by construction; an open-cell foam does not. The gasket seals a seam, but the immersion or IP rating is measured on the complete device per IEC 60529, not on the gasket. Send the sealing-window geometry and the target immersion, and let the tested device carry the rating. [12] [1]
Cushion and spacer: thickness, compression, and set
Rule — size the sensor and display cushions by thickness and compression, and make compression-set resistance the long-game criterion. A cushion sets the optical-sensor gap and protects the package from the flex and impact of a worn device; too thin and it does not protect, too firm and it disturbs the sensor. Microcellular PU holds its deflection over months of wear where a lesser foam relaxes and quietly drops the protection.
Compression-force-deflection is read per ASTM D3574, compression set per D395/D1056. Give the cushion thickness and the deflection the design achieves, not a single number. [11]
Repeated flex and washability: per-TDS limits, not a blanket claim
Rule — state the real flex and immersion duty and hold each layer to its per-TDS limits, not a blanket claim. Bands and patches flex thousands of times and see showers, swims, and hand-washing; the repeated-flex and wash/immersion limits are properties on the maker TDS, not a promise the converter can make. A skin adhesive has a stated wear window; a gasket and vent have stated cycle and immersion limits. State the real flex count and the wash/immersion exposure so each layer is chosen inside its duty. [6]
Acoustic and vent openings: pass sound, equalize pressure
Rule — protect the mic/speaker port with an acoustic mesh that passes sound and blocks water to a stated depth, and add an ePTFE vent to equalize pressure. The acoustic mesh keeps the port from flooding or clogging while passing sound to a stated immersion depth per the maker TDS; the ePTFE vent equalizes pressure across temperature and immersion cycles and blocks water and dust while passing moisture vapor.
Both figures are the membrane maker's grade ratings; the device's IP rating is on the tested unit. Give the port size and the immersion target, and specify the mesh and vent separately. [10]
Specification Tools
Two tools to take you from "we have a device that lives on the body" to here is the layer checklist for the drawing set: a requirement-driven on-body stack builder that assembles the layer list with its citations, and a side-by-side comparison of every on-body material family on this page.
1. On-body stack checklist builder
Check the requirements your worn device carries. The builder assembles the corresponding layers into a checklist with the family, what to send with the drawing, and the method language (skin adhesive per the maker TDS with ISO 10993 data from the maker; IP on the tested device per IEC 60529; foams per ASTM D3574/D1056/D395). The default selection is pre-built for a typical wearable patch; every layer is also printed in the material reference section, so nothing here exists only behind a script.
On-body stack checklist: 4 layers selected
Each checked requirement adds its layer below. The list is the starting bill of materials for the on-body review, not a rating: skin-adhesive values come from the maker TDS with biocompatibility data per ISO 10993 from the maker, any IP/water rating belongs to the complete tested device per IEC 60529, and foams are cited per ASTM D3574/D1056/D395.
- Skin-contact adhesive: silicone gel or gentle acrylicSend: skin footprint, target wear time, biocompat framing needed. Cite: ISO 10993 data per maker; ASTM D3330 peel (device side).
- Optical-sensor cushion: microcellular PU + light-block filmSend: sensor gap, window geometry, light-block need. Cite: CFD per ASTM D3574; compression set per D395.
- Perimeter seal: closed-cell silicone / PU gasketSend: sealing-window geometry, immersion target. Cite: closed-cell per ASTM D1056; IP on tested device per IEC 60529.
- Breathable path: ePTFE vent membraneSend: vent port size, MVTR / comfort target. Cite: MVTR per maker method; pressure equalization + water block per TDS.
2. Side-by-side: on-body material comparison matrix
Every family called out on this page, with construction, the property that drives its selection, the methods its TDS cites, and the zone it serves. Use the filters to narrow by group. Click any material name to jump to its accordion entry.
| Material | Construction | Selection property | Methods on the TDS | Zone | |
|---|---|---|---|---|---|
| Skin-contact adhesives | |||||
| Skin-Contact Silicone Gel PSASilicone gel adhesive | Soft silicone gel | Gentle, low-trauma, short wear | ISO 10993 (maker); ASTM D3330 | Skin adhesive | |
| Skin-Contact Acrylic PSAGentle acrylic adhesive | Acrylic film adhesive | Higher hold, longer wear | ISO 10993 (maker); ASTM D3330 | Skin adhesive | |
| Cushions, spacers & perimeter seals | |||||
| PORON® Microcellular PU CushionSensor / display cushion | Open-cell microcellular PU | Thickness + low compression set | ASTM D3574; D395 | Sensor, display | |
| Closed-Cell Silicone Foam GasketPerimeter sweat/splash seal | Closed-cell silicone foam | Seals into its window, low set | ASTM D1056; D395; IEC 60529 (device) | Perimeter seal | |
| Thin PU / PE Spacer FoamStack shim / spacer | Closed-cell PU / XLPE | Thickness + location tolerance | ASTM D3574; D1056 per TDS | Internal stack | |
| Vent & acoustic membranes | |||||
| ePTFE Vent MembraneBreathable pressure vent | Microporous PTFE | MVTR + water/dust block | Maker MVTR method; per TDS | Breathable path | |
| Acoustic Mesh / Vent MembraneMic / speaker protection | Microporous PTFE + mesh | Passes sound, blocks water to depth | Maker acoustic + immersion; per TDS | Mic / speaker | |
| Films, tapes & filter foam | |||||
| PET / Polyimide Light-Block FilmSpacer / light-block film | PET / polyimide film | Thin insulating / light-block | Per maker TDS | Sensor, stack | |
| Device-Side Bonding TapeTransfer / double-coated | Acrylic transfer / double-coat | Substrate-matched bond line | ASTM D3330 per TDS | Device-side bond | |
| Reticulated PU (acoustic / filter)Damping / filter foam | Open-cell reticulated PU | Acoustic damping / filtering | Per maker TDS | Mic / speaker | |
Skip ahead and request your on-body review now
If your drawing set already calls out a skin-contact adhesive, a sensor cushion, a closed-cell perimeter gasket, an ePTFE vent, or an acoustic mesh, send it over for review against the maker TDSs, including the adhesive maker's ISO 10993 data.
On-body failures you can prevent at spec
On-body parts fail personally and quietly: a skin adhesive strips skin on removal, an occlusive layer macerates skin over a day of wear, a perimeter gasket leaks sweat, a sensor reads noisy, an acoustic port floods. Five patterns cover most of what goes wrong on a worn device, and each is a specification decision made before the first part is cut.
The datasheet number is only as good as its test conditions, and two ratings are not the converter's to make. A skin-adhesive wear time without the maker's ISO 10993 data, an MVTR without its method, or an immersion figure attributed to a single gasket instead of the tested device are all incomplete or misplaced specs. Biocompatibility belongs to the device maker; the IP/water rating belongs to the complete tested device per IEC 60529.
Show all 5 failure modes tap to expand
1. Skin adhesive mismatch: trauma or early lift
Fix — choose the skin adhesive by wear time and removal trauma, against the maker TDS and the device maker's ISO 10993 evaluation. Too aggressive an acrylic strips skin and hair on removal; too weak an adhesive lifts early with sweat and motion. Silicone gel adhesives remove cleanly and reposition; gentle acrylics start low and build hold over time. The mismatch is not a converting error, it is a chemistry-to-wear-window mismatch made at spec.
State the target wear time and the skin footprint so the right chemistry is chosen, and keep the biocompatibility call with the device maker. [7] [6]
2. No moisture-vapor path: maceration and lift
Fix — design a moisture-vapor path with a breathable adhesive pattern and a vent, because an occlusive layer traps sweat. Skin under an occlusive adhesive or gasket transpires with nowhere to go; the trapped moisture macerates skin and lifts the patch within a day. The fix is a breathable adhesive pattern (perforation or zones) and, on a sealed housing, an ePTFE vent, with MVTR as the number. State the wear duration and comfort target so the vapor path is designed in, rather than discovered when the patch lifts in the field. [9] [8]
3. Sweat / splash ingress through the perimeter
Fix — seal the seam with a closed-cell gasket compressed into its window, and rate the complete device, not the gasket. A wearable housing seam leaks under sweat and hand-washing when the perimeter gasket is open-cell or is not compressed into a defined sealing window. A closed-cell silicone or PU gasket seals by construction; the water rating is then measured on the assembled device per IEC 60529. Send the sealing-window geometry and the immersion target, and let the tested device carry the rating rather than claiming it for one layer. [12] [1]
4. Optical cross-talk or sensor-gap error
Fix — set the sensor gap with a spacer and block stray light with an opaque ring. A PPG or optical heart-rate window without a light-blocking spacer sees stray light crossing between emitter and detector, and a window without a gap-setting cushion drifts as the device flexes on the wrist; both make the reading noisy. A thin microcellular PU cushion sets the gap and holds it under wear, and a light-block film rings the window. Give the sensor gap and the window geometry so the spacer is cut to set them. [11]
5. Acoustic port floods or muffles, or a cushion takes a set
Fix — protect the port with an acoustic mesh rated to a stated depth, and choose cushions and gaskets for compression-set resistance. A mic/speaker port with no protective mesh floods or clogs; a mesh under-rated for the immersion target lets water in; and a cushion or gasket that relaxes below its sealing or cushioning deflection over months of wear quietly drops the seal or the protection.
Specify the acoustic mesh to the immersion target per the maker TDS, and choose microcellular PU and closed-cell silicone for their low compression set over the wear life. [10] [12]
Material reference
Detailed specs for the on-body families referenced on this page: the skin-contact adhesives (silicone gel and gentle acrylic), the cushions and seals (PORON® microcellular PU, closed-cell silicone-foam perimeter gasket), the vent and acoustic membranes (ePTFE vent, acoustic mesh), and the spacer, film, and device-side tape families.
Values are per the maker TDS on file for each grade with the method named; skin-contact biocompatibility data comes from the adhesive maker per the ISO 10993 series, and any IP/water rating belongs to the complete tested device per IEC 60529.
H-O die-cuts, kiss-cuts, laminates, and kits every family to drawing; H-O converts and does not certify biocompatibility or systems.
Skin-Contact Silicone Gel PSAGentle, repositionable, low-trauma skin adhesive · biocompatibility per ISO 10993 from the maker
Send the skin footprint and target wear time. The biocompatibility data and the skin-safety call belong to the adhesive maker and the device maker; H-O converts and does not certify.
Skin-Contact Acrylic PSAHigher-hold, longer-wear skin adhesive · biocompatibility per ISO 10993 from the maker
A gentle acrylic trades some removal comfort for longer wear; confirm the wear window and the maker's ISO 10993 data on the current TDS.
PORON® Microcellular PU Cushion & SpacerSensor / display cushion · sets the optical-sensor gap · low compression set · ASTM D3574 / D395
Give the cushion thickness and the deflection the design achieves, not a single number; compression set decides whether it still protects at the end of the wear life.
Closed-Cell Silicone Foam Perimeter GasketSweat / splash perimeter seal · seals into its window · ASTM D1056 / D395 · IP on the tested device
Send the sealing-window geometry and the target immersion; the gasket seals the seam, and the tested device carries the IP rating.
ePTFE Vent MembraneBreathable pressure vent · passes moisture vapor, blocks liquid water · per maker TDS
Give the vent port size and the comfort/MVTR target; the membrane grade follows from the breathability and immersion requirement per the maker TDS.
Acoustic Mesh / Vent MembraneMic / speaker protection · passes sound, blocks water to a stated depth · per maker TDS
Give the port size and the immersion target; the mesh grade follows from the acoustic and immersion requirement per the maker TDS.
Thin Spacer / Stack Foams & FilmInternal shims, gap-set, light-block · PU / PE foam + PET / polyimide film · ASTM D3574 / D1056
Kit the whole stack on one liner in assembly order and the line builds it faster; send the layer thickness and location tolerance.
Device-Side Bonding TapesCover-lens and layer bonding · acrylic transfer / double-coated · substrate-matched · ASTM D3330
Give the housing substrate and the bond geometry; the tape is matched to the surface energy, and it is not for skin contact.
Cellular Silicone Glazing & Perimeter GasketsTemperature- and flame-driven gaskets · UL 94 per grade TDS · ASTM D1056
Where the gasket itself must carry a UL 94 flame class, specify a V-0 grade and state the class per the grade TDS; the class belongs to the material grade, not to any facade rating.
Wearable & on-body materials: engineer-grade FAQ
Twelve of the questions we hear most from hardware and industrial-design engineers building worn devices. If your question isn't here, send a drawing or call, engineering picks up.
Silicone or acrylic skin-contact adhesive — which for a wearable?
It comes down to wear time and removal trauma. A silicone gel adhesive is gentle, repositionable, and low-trauma on removal, so it suits sensitive skin and shorter wear. A gentle acrylic starts lower and builds hold over time, reaching longer multi-day wear at the cost of more removal trauma. Choose against the maker TDS and the device maker's ISO 10993 evaluation, and send the target wear time and skin footprint so the chemistry is chosen first. [7]
Is H-O a medical-device supplier, FDA-registered, or ISO 13485 certified?
No. H-O is an ISO 9001:2015 certified organization and does not hold ISO 13485, is not FDA-registered, and does not make a medical claim. Biocompatibility for a skin-contact part is evaluated per the ISO 10993 series, and that evaluation belongs to the finished device and its adhesive maker. H-O the converted skin-contact layer and passes through the adhesive maker's ISO 10993 data and lot traceability; the skin-safety and biocompatibility call is the device manufacturer's. [2]
How long can a skin-contact adhesive be worn?
It runs from short-term to long-term, per the maker TDS. Short-term wear is about a day; long-term wear reaches multiple days or weeks on the right chemistry. Silicone gel favors gentle short wear; a gentle acrylic reaches longer multi-day wear as it builds hold. The wear time is a skin-panel property on the adhesive maker's TDS, not a number H-O invents, so send the target duration and the device program's biocompatibility framing and the right grade is matched to it. [6]
What is MVTR and why does breathability matter?
MVTR is moisture-vapor transmission rate, in grams per square metre per day. It matters because skin under an occlusive layer transpires, and trapped moisture macerates skin and lifts the patch. Worn devices run roughly 600–1,400 g/m²/day at room temperature, with vapor-permeable fabrics higher (about 3,500–3,600) and conductive hydrogels higher still (about 4,000–5,000), stated as device-patent ranges per the maker method. A breathable adhesive pattern plus an ePTFE vent gives the vapor a path out. [9]
How do I seal a wearable against sweat and splash?
With a closed-cell perimeter gasket compressed into its sealing window. A closed-cell silicone or PU gasket seals the housing seam against sweat and splash by construction, where an open-cell foam would not. The important honesty point: the water or immersion rating belongs to the complete tested device measured per IEC 60529, not to the gasket alone. Send the sealing-window geometry and the target immersion, and let the assembled, tested device carry the IP rating. [12] [1]
What sets the optical / PPG sensor gap?
A thin spacer, paired with a light-block film. A PPG or optical heart-rate window needs the sensor held at the right gap to the skin, and it needs stray light blocked so it does not cross between the emitter and the detector. A thin microcellular PU cushion sets the gap and holds it under the flex of a worn device, and an opaque film rings the window as the light-block mask. Give the sensor gap and the window geometry so the spacer is cut to set both. [11]
How is a mic or speaker protected on a worn device?
With a small acoustic mesh over the port. The mesh passes sound while blocking water and dust to a stated immersion depth per the maker TDS — some portable and wearable acoustic grades are rated waterproof to a stated depth such as 30 m. Reticulated PU behind the mesh damps and filters where the acoustic design calls for it. As with every opening, the stated depth is the membrane maker's grade rating; the device's overall IP rating is on the complete tested unit. [10]
Why add an ePTFE vent to a sealed wearable?
To equalize pressure and give moisture vapor a path, while keeping water and dust out. A sealed housing draws a pressure difference across temperature and immersion cycles; an ePTFE vent membrane equalizes it so the housing does not pull water in as it cools, and it passes moisture vapor so the interior does not stay damp. It is microporous PTFE: breathable to vapor, a barrier to liquid water and dust. It is a small disc mounted over a vent port, not a load-bearing gasket. [10]
Can H-O the whole on-body stack and kit it?
Yes. H-O die-cuts, kiss-cuts, laminates, and kits the skin adhesive, sensor and display cushions, perimeter gaskets, vent and acoustic membranes, and internal spacers to the customer drawing, with liner and pull tabs for line assembly. The whole on-body stack can ship as a kitted set, one kit per unit, parts on liner in assembly order, with lot-code TDS records per material (including the adhesive maker's ISO 10993 data for skin-contact layers).
H-O converts made-to-order as an ISO 9001:2015 certified organization and does not certify biocompatibility or systems.
How thin can these layers be?
Per the maker TDS, into the sub-millimetre range some grades support. On-body stacks live on thin layers: skin adhesives on thin film carriers, microcellular PU cushions and thin spacer foams, and film shims measured in fractions of a millimetre. The achievable thickness and tolerance belong to the specific grade and the method, so H-O quotes it against the drawing rather than a blanket minimum. Send the target thickness and tolerance and engineering confirms it against the grade TDS. [11]
What about repeated flex and washability?
They are per-TDS duty limits, not a blanket claim. Bands and patches flex thousands of times, and consumer devices see showers, swims, and hand-washing. The repeated-flex and wash/immersion limits are properties on the maker TDS for each layer, and the device's water resistance is measured on the complete tested unit per IEC 60529. State the real flex count and the wash or immersion exposure so each layer is chosen inside its stated duty; H-O does not make a blanket water-resistance promise for a converted layer. [6]
What should I put on the drawing so the quote comes back right?
The device and the stack, not just one part: the device type (watch, band, patch, pod), the skin-contact footprint and target wear time, the biocompatibility framing your program needs from the adhesive maker, the moisture-vapor or breathability need, the IP or immersion target, the sensor-window and display cushion geometry, the internal spacer or stack drawing, the mic/speaker port size, and the housing substrate for the device-side PSA.
Plus prototype and annual volume. "Recommend the material" is a valid callout: that is what the on-body review is for.
Glossary: terms used on this page
Quick reference for the on-body terminology used throughout. Each entry links to the relevant standard or test method where applicable.
ISO 10993 (biocompatibility)
The series that governs the biological evaluation of skin-contact parts, by designation, per [2] (-1 evaluation, -5 cytotoxicity, -10 irritation and skin sensitization, -11 systemic toxicity). The evaluation belongs to the finished device and its adhesive maker; H-O passes through the maker's data and makes no certification claim.
Skin-contact PSA
A pressure-sensitive adhesive intended to hold a device to skin for a defined wear time, then release. Silicone gel is gentle and repositionable; a gentle acrylic builds hold for longer wear. Selected by wear time and removal trauma, with biocompatibility data per the maker's ISO 10993 series. [7]
Low-trauma / gentle removal
The property of a skin adhesive that releases without stripping skin or hair. Silicone gel adhesives remove cleanly and can be repositioned; gentle acrylics remove with more trauma as they build hold over time. A wear-comfort property on the adhesive maker's TDS. [6]
Wear time
How long a skin-contact adhesive is intended to stay adhered, from short-term (about a day) to long-term (multiple days or weeks). A skin-panel property on the adhesive maker's TDS, not a number the converter sets. [6]
MVTR (moisture-vapor transmission rate)
The rate at which moisture vapor passes through a layer, in g/m²/day. Worn devices run roughly 600–1,400 g/m²/day; fabrics and hydrogels far higher, per device-patent ranges. A low MVTR (occlusion) macerates skin and lifts a patch. [9]
Breathable membrane / ePTFE
Microporous expanded PTFE that passes moisture vapor while blocking liquid water and dust. Used as a wearable vent to equalize pressure across temperature and immersion cycles while keeping the interior dry. [10]
IEC 60529 (IP code)
The standard defining ingress-protection (IP) ratings, by designation, per [1]. The rating is measured on the complete tested device; immersion digits do not imply jet ratings unless both are marked. A single gasket or mesh does not carry the rating.
Compression force deflection (CFD)
The force a foam gasket or cushion resists at a stated deflection, per ASTM D3574 [4] (cellular urethane) or D1056 (cellular rubber). It specifies a cushion or seal as a spring, not just a thickness.
Compression set
The permanent thickness a foam loses after sustained compression, per ASTM D395 / D1056 [4]. A cushion or gasket that takes a set below its sealing or cushioning deflection quietly drops the seal or protection over the wear life. [12]
Acoustic vent membrane
A microporous membrane/mesh over a mic or speaker port that passes sound while blocking water and dust to a stated immersion depth per the maker TDS. Reticulated PU behind it damps and filters where the acoustic design calls for it. [10]
Siloxane (silicone) contamination note
Low-molecular-weight siloxane can migrate from a silicone layer and condense on nearby optics or foul a contact. Where an optical window or sensor is nearby, a non-silicone equivalent avoids it; flag it on the drawing so the material track is chosen up front.
Die-cut spacer / stack layer
A thin shim of foam or film that sets a gap and locates a component inside a patch or pod. Geometry-driven: the drawing note is the thickness and the location tolerance, not a material headline.
PPG / optical sensor window
A photoplethysmography (optical heart-rate) window that reads light reflected from skin. It needs a spacer to set the sensor-to-skin gap and a light-block ring to stop stray light crossing between emitter and detector. [11]
"Rating belongs to the tested device" rule
The honesty rule for this page: an IP or water rating is measured on the complete tested device per IEC 60529 [1], and biocompatibility is the device maker's ISO 10993 evaluation. A single converted gasket, vent, mesh, or adhesive layer does not carry either claim; H-O converts and does not certify.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified organization, Winsted, CT).
Standards, test methods & technical references
The standards, test methods, and maker technical data sheets cited throughout this page. Standards editions current as of July 2026; verify against the publishing body before final spec. H-O materials are aligned to these standards through the source manufacturer's TDS, not independently certified by H-O; biocompatibility belongs to the finished device and its maker, and any IP/water rating belongs to the complete tested device.
[1] IEC 60529 (IP Code)
IEC 60529 — Degrees of Protection Provided by Enclosures (IP Code). The ingress rating is measured on the complete tested device; immersion digits do not imply jet ratings unless both are marked. iec.ch (IEC 60529)
[2] ISO 10993 (biocompatibility)
ISO 10993 — Biological Evaluation of Medical Devices (series: -1 evaluation, -5 cytotoxicity, -10 irritation and skin sensitization, -11 systemic toxicity). The evaluation belongs to the finished device and its adhesive maker; H-O passes through the maker's data and makes no certification claim. iso.org (ISO 10993)
[3] ISO 10993 for skin-contact adhesives (The Tape Lab)
Understanding ISO 10993: biocompatibility for skin-contact adhesives — converter application background on the ISO 10993 series and how skin-contact PSAs are evaluated. Confirm the specific adhesive's data on its maker TDS. thetapelab.com (ISO 10993 background)
[4] ASTM D3574 / D1056 / D395 / D2240 (foam)
ASTM D3574 (cellular urethane), D1056 (cellular rubber), D395 (compression set), and D2240 (durometer hardness). The foam methods that specify a cushion or gasket as a spring and quantify how much it relaxes over the wear life. astm.org (ASTM D3574)
[5] ASTM D3330 (PSA peel)
ASTM D3330 — Standard Test Method for Peel Adhesion of Pressure-Sensitive Tape. The peel method for device-side adhesive layers; skin-adhesion and wear-time claims come from the adhesive maker's skin-panel data, not this bench method. astm.org (ASTM D3330)
[6] Short- vs long-term wear stick-to-skin adhesives (JBC)
JBC Technologies — short- vs long-term wear stick-to-skin adhesives. Application background on wear time (short-term about a day to long-term multi-day/weeks) and the silicone-vs-acrylic trade. jbc-tech.com (wear time)
[7] Silicone vs acrylic skin adhesive (Strouse)
Strouse — silicone vs acrylic skin adhesive. Application background on the silicone-gel (gentle, repositionable, low-trauma) vs gentle-acrylic (higher hold, builds over time, more removal trauma) trade for wearables. strouse.com (silicone vs acrylic)
[8] Adhesives for wearables (Avery Dennison)
Avery Dennison Medical — types of adhesives for wearables. Application background on matching the adhesive to substrate and surface energy, and on breathable adhesive constructions for worn devices. averydennison.com (wearable adhesives)
[9] MVTR ranges, wearable medical device (USPTO)
US Patent 11,890,461 — adhesively coupled wearable device. Source for the worn-device MVTR ranges (roughly 600–1,400 g/m²/day; fabrics ~3,500–3,600; hydrogels ~4,000–5,000), stated per the patent method. uspto.gov (US 11,890,461)
[10] ePTFE vent & acoustic membranes (Gore / Electronics Weekly)
GORE enclosure pressure relief (ePTFE vents) and acoustic vents for portables/wearables — passes sound and moisture vapor while blocking water to a stated depth (e.g. 30 m per grade). Verify the grade rating on the maker TDS. gore.com (pressure relief) · electronicsweekly.com (acoustic vent)
[11] PORON microcellular PU cushioning (SRP / Modus)
PORON microcellular polyurethane cushioning for optical/camera and wearable devices, into thin with low compression set. Grade specifics per the maker TDS. srpco.com (PORON cushioning)
[12] PORON vs BISCO silicone foam sealing (Modus Advanced)
Modus Advanced — gaskets for water sealing: PORON vs BISCO silicone foam. Application background on closed-cell silicone foam sealing sweat/splash by construction, with the water rating on the complete tested device. modusadvanced.com (water sealing)
Updated . Standards editions and links current at publication; verify against the publishing body before final spec. H-O converts materials tested to the methods cited; H-O does not certify materials, systems, or biocompatibility. Biocompatibility belongs to the finished device and its maker; any IP/water rating belongs to the complete tested device. Lot-specific documentation available on request.
To review your on-body design, send:
- Device type (watch / band / patch / pod)
- Skin footprint and target wear time
- Biocompatibility framing from the adhesive maker
- Moisture-vapor / breathability need
- IP / immersion target (on the tested device)
- Sensor-window and display cushion geometry
- Internal spacer / stack drawing
- Mic / speaker port size
- Housing substrate (for device-side PSA)
- Prototype and annual volume
Get a wearable & on-body materials quote
Send a drawing set, BOM, or stack description. We typically respond within one business day with a material recommendation, prototype lead time, and TDS verification against your skin footprint, wear time, sealing window, and openings — passing through the adhesive maker's ISO 10993 data for any skin-contact layer.
See also: related H-O application pages
Engineering content for the adjacent electronics and IoT sub-applications and the parent hub. Each page covers material selection, failure modes, and converter-side process detail for its application family.
Sibling sub-application
Enclosure sealing & IP protection
The perimeter-sealing discipline at housing scale: closed-cell gaskets and IP-rated seals, with the same rule that the rating belongs to the tested device.
Read the page
Sibling sub-application
Electronics thermal management
Where a worn device runs warm: die-cut thermal interface pads, gap fillers, and graphite spreaders for the compute and sensor package inside.
Read the page
Sibling sub-application
Display & PCB shock protection
The cushioning discipline for the display and board a worn device drops and flexes: die-cut PORON® and PU pads that protect on impact.
Read the page
Sibling sub-application
Bonding & assembly adhesive tape
The device-side tapes that bond the cover lens and stack the layers: acrylic transfer and double-coated tapes matched to the housing substrate.
Read the page
Sibling sub-application
Small battery packs
The compression and spacer stack for the small Li-ion cell that powers a worn device, where cushioning meets the on-body layers.
Read the page
Industry hub
Electronics & IoT
The full electronics and IoT application family: thermal, sealing, shock, bonding, battery, and on-body materials H-O converts.
Read the page
Material data & standards. All material values on this page are taken from the source maker's technical data sheets with the method named (biocompatibility per the ISO 10993 series from the adhesive maker; ingress protection per IEC 60529 on the complete tested device; foam properties per ASTM D3574, D1056, D395, and D2240; PSA peel per ASTM D3330; UL 94 classes where a pod battery requires it, per the listed grade TDSs).
Biocompatibility belongs to the finished device and its maker, and any IP or water rating belongs to the complete tested device, not to a single converted layer. H-O is an ISO 9001:2015 certified organization; it converts materials and does not certify systems or biocompatibility, and makes no ISO 13485, FDA, or medical claim. Verify against the maker TDS for your device and duty.
Conversion scope. H-O and converts sheet, roll, and film stock to drawing in Winsted, Connecticut: die-cut and kiss-cut skin adhesives, cushions, gaskets, vent and acoustic membranes, spacers, and films, slit films, laminations, and kitted on-body stacks, with material traceability and lot-code TDS records. H-O does not mold or extrude these materials in its own plant; molded or extruded profiles are coordinated through a partner network. Lead-time and MOQ details are in the process strip and the quote form above.