Compatibility Matrix: Metals, Oils, Plastics, and Skin Products
Safety. Solvent cements and some oils are flammable. Oil on a latex glove or a worn film can chemically damage the rubber, not only act as a slip layer. Read the product SDS.
Executive summary
This is a never / avoid / conditional / OK grid for what touches natural rubber. The same cured film sees copper-catalyzed aging and oil swell whether it started as bought sheet or as a dried latex coat. Wet latex in a bottle or a hose is a different contact state: brass, copper, and wet galvanized fittings are never acceptable there.
Petroleum and mineral-oil skin products can chemically damage thin NR barriers. Use the grid when you pick a bottle, a tray, a snap, or a cream that will sit on rubber. Fastener taxonomy lives in Sheet Hardware & Metal Contact and Liquid Hardware & Metal Contact.
How to read the ratings
| Rating | Meaning here |
|---|---|
| Never | Sources forbid the contact. |
| Avoid | Sources treat the contact as harmful. Do not plan around it. |
| Conditional | Allowed only under the conditions in the blurb under each table. If the sources do not give those conditions, the blurb says no data. |
| OK | Sources name the contact as acceptable. |
What is NR?
NR is natural rubber, the polymer from Hevea latex. Here it means the wet compound in a bottle and the cured film you wear or store, not a synthetic paint that happens to be labeled “latex.”
Metals
| Contact | Wet latex compound | Cured NR film | Why |
|---|---|---|---|
| Brass / copper / bronze | Never | Avoid direct | Catalytic poison; serious deterioration of rubber in latex |
| Galvanized (wet) | Never | Avoid wet | Coagulum in the liquid; wet zinc-coated steel is the sheet-side problem |
| Black iron / stainless (clean) | OK with hygiene | Conditional | Plant fittings: black iron or stainless, not brass |
| Unknown plated snap | — | Avoid until verified | Finish name is not a base-metal proof. See sheet hardware |
Conditional: clean black iron or stainless on cured film. The handbook accepts black iron and stainless for fittings that touch wet latex, if they stay clean. On a worn film, sweat in a crevice around a snap or eyelet is the condition that makes the cell uncertain. Wear-time rating for that crevice: no data.
Concrete examples: a brass garden-hose barb on a latex bottle; a zinc-coated steel bucket under a wet jug; a sewing-shop snap stamped “antique brass” with no substrate listed.
Oils and plasticizers
| Contact | Cured NR film | Why |
|---|---|---|
| Petroleum / mineral-oil skin product | Avoid on the wear surface | Oil-based creams deteriorate latex gloves (NIOSH / OSHA) |
| Silicone polish / lube | Conditional | See blurb |
| NR vs CR vs XNBR oil resistance | CR and XNBR beat NR | Glove-film order: NR worst, then CR, then XNBR |
Conditional: silicone polish or lube. Sources do not rank silicone against mineral oil on fashion film. Garment wear rating: no data.
IRM lab oils belong to the ASTM D471 method class. They rank swell in a coupon test. They are not a wear certificate.
What is oil swell?
Oil swell is how much a rubber coupon grows after a soak in oil. ASTM D471 is the method class for that ranking. Chloroprene (CR) and carboxylated nitrile (XNBR) glove films resist oils better than natural rubber. A catsuit panel is not a glove coupon.
Plastics
| Material | Wet latex storage | Cured film contact | Notes |
|---|---|---|---|
| PE / PP (clean) | Conditional | Conditional | See blurbs |
| Soft PVC | Avoid long soak | Avoid | Plasticizer can move into rubber |
Conditional: PE / PP for wet latex. Clean polyethylene or polypropylene shows up as a lab-storage option. The condition is a clean bottle of a known grade, not a mystery food tub. Brand-by-brand ratings: no data.
Conditional: PE / PP against cured film. Sources do not rate a worn panel sitting in a PE bag or on a PP tray. Contact rating: no data.
Example of Avoid: a soft vinyl pouch or inflatable left against sheet for weeks.
Skin and body products
Not medical advice. NIOSH and OSHA are writing about latex gloves.
Petroleum jelly and mineral-oil hand cream: Avoid on the wear surface. Those products deteriorate latex glove film.
Sunscreen, perfume, and silicone lube: Conditional. Fashion-film ratings: no data.
Deep dives (optional)
Deep dive: Copper catalysis and antioxidant reserve
Trace copper catalyzes degradation of unsaturated rubber. Sudsai’s work uses copper oleate as the catalyst and notes dark spots from copper in containers. Fatty-acid salts of copper, manganese, and iron belong to the same catalytic class.
For films that will see copper, industrial compounding uses 2 phr total antioxidant: one phr for ordinary oxidation, one phr held in reserve for copper. Antioxidant is consumed as the film ages. If the reserve is gone, copper contact fails the film early.
What is phr?
phr means parts per hundred rubber: parts by weight of an additive per 100 parts of dry rubber. 2 phr antioxidant is 2 grams of antioxidant per 100 grams of rubber, not 2% of the wet bottle.
Deep dive: Oil-swell method class
ASTM D471 measures how oils, greases, and fuels change vulcanized rubber (swell, tensile, hardness). Use it to rank liquids. Do not treat a D471 number as a garment pass.