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Foam, Drape or Adhesive? Choosing Materials for NPWT and Wound-Care Devices
A negative pressure wound therapy (NPWT) device and related wound-care products are built from a small set of die-cut materials, each doing a different mechanical job: an open-cell interface foam that lets fluid and air pass through it, a drape film that supports a seal, a skin-contact adhesive border that attaches the drape, and a microcellular pad that cushions or offloads.
These are foam, film and adhesive materials, selected for porosity, barrier behavior, moisture-vapor transmission and peel. This guide separates the materials and maps each to a family H-O Products converts, at the material level only, with no claim about treating or healing.
The application problem: three materials around one device
A negative pressure wound therapy (NPWT) device and related wound-care products are built from a small set of die-cut materials, each doing a different mechanical job. There is an open-cell interface foam that sits at the device side and lets fluid and air pass through it under reduced pressure, a drape film that covers the site and holds a seal so the reduced pressure is maintained, and a skin-contact adhesive border that attaches the drape to the surrounding skin.
These are foam, film and adhesive materials, selected for their mechanical and material-level properties. This guide separates the materials and maps each to a family H-O Products converts, at the material level only.
- Interface foam: an open-cell, reticulated polyurethane foam with a through-porous structure that lets fluid and air move through it; selected for its porosity, its open-cell structure and its material-level designation.
- Drape film: a thin, conformable film that covers the site and supports the seal; selected for conformability, moisture-vapor behavior and the adhesive it carries.
- Skin-contact adhesive border: a pressure-sensitive adhesive that attaches the drape to skin; selected for the wear window, the backing and a material-level ISO 10993-10 evaluation.
- Support and offloading pad: a microcellular foam that cushions or offloads at low contact pressure around the device.
Why is choosing these materials challenging?
The materials have different and sometimes opposing requirements. The interface foam must be open and porous so air and fluid move through it, while the drape must be closed and sealing so the reduced pressure is held; one is deliberately permeable and the other deliberately not. The drape must conform and seal yet also manage moisture vapor so the construction behaves predictably over a wear window, and the skin adhesive must hold the drape for that window while releasing cleanly and carrying a material-level skin-contact evaluation.
None of these is a therapy property; they are foam porosity, film barrier, moisture-vapor transmission, and adhesive peel and designation, each read off the maker's data sheet. The selection is a materials exercise, and the device maker owns everything about the finished device and its use.
Recommended material families
Each material maps to a family H-O Products converts. A family is named on this page only where it is catalog-verified; grade-level values such as porosity, force-deflection, moisture-vapor transmission and peel are confirmed against the manufacturer's current technical data sheet before specifying.
For the interface foam: reticulated open-cell polyurethane
medical reticulated open-cell polyurethane foam, with the uncoated reticulated polyurethane base material and the acrylic-coated reticulated grade as related options, has a through-porous, open-cell structure that lets fluid and air move through it.
Pore size (commonly expressed in pores per inch) and the open-cell structure are grade-specific and characterized per ASTM D3574; medical grades are offered with documentation aligned to ISO 10993 and USP Class VI by designation. Confirm the grade, the pore range and the documentation on the data sheet. This describes the foam material only.
For the drape film and seal: thin conformable film with a skin-contact border
The drape is a thin film that covers the site and supports the seal, carrying a microcellular and skin-contact material family at its skin-side border. The film is selected for conformability and moisture-vapor behavior (characterized per ASTM E96), and the border adhesive for the wear window. The seal belongs to the finished construction and the device; the materials are selected for their mechanical and material-level properties.
For the skin-contact adhesive: skin PSA evaluated to ISO 10993-10
The skin-side border uses a skin-contact and breathable material family, converted as a die-cut border on a release liner. The adhesive is evaluated by the material maker against ISO 10993-10 for sensitization and irritation as a material-level designation, and its peel is characterized per ASTM D3330. The finished-device skin-contact assessment belongs to the device maker.
For support and offloading: microcellular polyurethane
A microcellular grade of the same foam family cushions or offloads at low contact pressure around the device, characterized per ASTM D3574 with compression set per ASTM D395. This is a cushioning material selection; it is not a therapy claim. Confirm the grade on the data sheet.
Foam, Drape, Adhesive or Support: Material-Role Direction Selector
A through-porous, open-cell reticulated polyurethane lets fluid and air move through it; the pore range and any material-level documentation are confirmed on the data sheet. This is a foam material selection only.
Illustrative only; confirm against current material data and a drawing review. This selector returns a material family direction, not a grade, a pore size or any clinical or therapeutic claim, and it makes no claim that any material treats or heals a wound. Porosity, force-deflection, moisture-vapor transmission, peel and any ISO 10993 / USP Class VI documentation are confirmed on the manufacturer's current technical data sheet, and the finished device, its indications and its use belong to the device maker.
Design and converting considerations
- Specify foam and drape separately. The interface foam is open and porous; the drape is a closed sealing film. They are opposite by design and selected by different properties.
- Pore range is a foam spec. Pores per inch and the open-cell structure are grade-specific; send the range you need and confirm it on the data sheet.
- Read the drape construction together. Film, moisture-vapor behavior and the border adhesive are read as one; the seal belongs to the finished construction.
- Skin adhesive is a material-level evaluation. Ask for the ISO 10993-10 designation on the grade; the finished-device skin-contact assessment is the device maker's.
- Process fit. These materials are die-cut, kiss-cut, laser or rotary cut, laminated and supplied on liners, sized to the device geometry and kitted for assembly.
Common material mismatches
| Mismatch | Root cause | Material direction |
|---|---|---|
| Fluid and air do not pass the interface foam | A closed-cell foam used where an open, through-porous structure is needed | Use a reticulated open-cell polyurethane; confirm pore range per the data sheet |
| Seal not held by the drape | An overly permeable film used where a closed sealing barrier is needed | Select a closed drape film; read its barrier and moisture-vapor behavior |
| Skin border lifts over the wear window | Adhesive or backing mismatched to the wear time and moisture | Reselect the skin PSA family and a breathable backing; confirm peel and the ISO 10993-10 designation |
| Pore size assumed | Foam ordered without a stated pore range | State pores per inch; the open-cell range is grade-specific on the data sheet |
| Foam, drape and adhesive conflated | One "wound material" specified for three different roles | Specify the foam, the drape and the adhesive separately by their own properties |
How H-O Products helps
H-O Products is a precision die-cut converter serving medical and clean-component programs. For wound-care and NPWT devices we convert reticulated open-cell polyurethane foam, drape films, skin-contact adhesive borders and microcellular support foams to your geometry and kit them for assembly. As an ISO 9001:2015 certified organization we help you specify the foam, the drape and the adhesive separately by their mechanical and material-level properties, and request the material-level documentation you need.
We do not produce the raw foam, film or adhesive, and we do not make the finished device; grade values and any ISO 10993 or USP Class VI documentation are confirmed against the manufacturer's current technical data sheet, and the finished device, its indications and its use belong to you. We make no claim that any material treats or heals a wound.
Specifying foam, drape and adhesive for an NPWT or wound-care device?
Tell us the material role at each location, the pore range or barrier you need, the wear window and any material-level documentation (ISO 10993, USP Class VI by designation). We will recommend a family direction for each material and convert samples on your geometry.
Samples typically ship in 3 to 5 business days for common die-cut configurations; standard production runs about two weeks; special orders are quoted to the job.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
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Frequently asked questions
What materials make up an NPWT device dressing?
An NPWT device dressing is built from die-cut materials: a reticulated open-cell polyurethane interface foam that lets fluid and air pass through it, a conformable drape film that supports the seal, a skin-contact adhesive border that attaches the drape, and sometimes a microcellular support or offloading pad. Each is a different material family selected for its mechanical and material-level properties, such as porosity, barrier behavior and peel.
H-O Products converts these families to your geometry; grade values are confirmed against the manufacturer's current technical data sheet. This describes the materials only, not a therapy.
What does reticulated open-cell foam mean, and why is it used here?
Reticulated open-cell polyurethane foam has a through-porous structure, meaning its cell walls are largely removed so fluid and air can move through the foam. Pore size is commonly expressed in pores per inch and is grade-specific, characterized per ASTM D3574. It is used as the interface foam because that role needs a permeable material, in contrast to the drape, which is a closed sealing film. H-O names a grade only where it is catalog-verified and confirms the pore range on the data sheet. This is a material property description, not a clinical claim.
Does H-O make any claim about wound healing?
No. H-O Products is a die-cut converter of foam, drape and adhesive materials, and makes no claim that any material treats, heals, manages or improves a wound or any condition. Wound healing, therapy, indications and clinical outcomes are the responsibility of the finished device and its maker. The only certification H-O claims is ISO 9001:2015 for the converting process; it is not an ISO 13485, FDA or cleanroom certified provider, and material-level designations such as ISO 10993 describe the material, not the device.
Request a quote for your NPWT or wound-care material
Send H-O your geometry or describe the material stack—engineering reviews every RFQ, recommends a family per material, and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- ASTM D3574, Standard Test Methods for Flexible Cellular Materials: Slab, Bonded, and Molded Urethane Foams. ASTM International.
- ISO 10993-1, Biological Evaluation of Medical Devices, Part 1: Evaluation and Testing Within a Risk Management Process. International Organization for Standardization (material-level designation).
- ISO 10993-10, Biological Evaluation of Medical Devices, Part 10: Tests for Skin Sensitization. International Organization for Standardization (material-level designation).
- USP Class VI, United States Pharmacopeia, Biological Reactivity Tests, In Vivo (material-level designation).
- ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials. ASTM International.
- Manufacturer technical data sheets for the named material families (medical reticulated polyurethane foam, skin-contact adhesive and drape film grades); grade-specific values and material-level documentation are confirmed on the maker's current TDS.
This article describes material families H-O Products converts for negative pressure wound therapy (NPWT) and wound-care devices and cites published standards by designation (ASTM D3574 for urethane cellular materials, ISO 10993 and USP Class VI as material-level designations, ASTM E96 for water-vapor transmission, ASTM D3330 for peel adhesion). It describes foam, drape and adhesive materials only.
It makes no patient, clinical or therapeutic claim, and no claim that any material treats, heals, manages or improves a wound or any condition; wound healing, therapy and clinical outcomes are the responsibility of the finished device and its maker, not of any material described here.
The material maker characterizes and documents a grade on its current technical data sheet; the device maker owns the finished device, its indications, its biocompatibility assessment and its regulatory file. H-O Products is a precision die-cut converter, not a raw-material producer and not a medical-device manufacturer; this is not, and does not imply, an ISO 13485 certification, an FDA device registration, a cleanroom certification or a biocompatibility certification.
The only certification claimed is ISO 9001:2015, which governs the converting process. Grade-specific values are confirmed against the manufacturer's current technical data sheet and an engineering drawing review. All parts are custom manufactured to order and minimum production run quantities apply.