Chemical Resistance Guide
Chemical Resistance Guide
Polyurethane timing belts and their cover materials offer varying degrees of chemical resistance depending on the compound and backing selected. Use this guide to identify compatible materials for your operating environment. For material compound selection, see the materials guide. For food-grade chemical compatibility, see the FDA page.
- Polyurethane: excellent oil, grease, ozone resistance
- Nitrile (NBR): excellent fuel and solvent resistance
- PTFE (Teflon): excellent for nearly all chemicals
- Silicone: high-temperature chemical resistance
- Sample materials available for immersion testing
- Stainless steel cords for corrosive environments
- Sealed AU1 cords for full washdown
- Contact us for specific chemical assessments
Compatibility Ratings
| Rating | Description | Guidance |
|---|---|---|
| Excellent | Suitable for continuous contact | Material is fully resistant; standard use is appropriate |
| Good | Suitable for intermittent contact | Material performs well with periodic exposure |
| Conditional | May be suitable; testing recommended | Request sample material for immersion testing before specifying |
| Not Recommended | Not suitable for contact | Choose an alternative material or cover |
Common Chemical Compatibility
The table below shows compatibility ratings for the most commonly encountered chemicals in industrial environments. For chemicals not listed, contact Texas Belting at 888-203-2358 for a specific assessment.
| Chemical | Polyurethane | Nitrile Rubber | PTFE (Teflon) | Notes |
|---|---|---|---|---|
| Water | Excellent | Excellent | Excellent | All materials compatible |
| Mineral oil | Excellent | Excellent | Excellent | Use oil-resistant covers for direct contact |
| Citric acid | Excellent | Excellent | Excellent | Safe for food processing |
| Sodium chloride (salt) | Excellent | Excellent | Excellent | Good salt resistance across all materials |
| Glucose (sugar solutions) | Excellent | Excellent | Excellent | Suitable for food and beverage applications |
| Hydraulic oil (mineral-based) | Not Recommended | Conditional | Excellent | Select oil-resistant covers or PTFE |
| Ethyl alcohol (ethanol) | Not Recommended | Excellent | Excellent | Use nitrile or PTFE covers for distillery applications |
| Acetone | Not Recommended | Conditional | Excellent | Use PTFE cover for acetone exposure |
| Gasoline | Not Recommended | Excellent | Excellent | Nitrile or PTFE required |
Material Categories
Belt compounds and cover materials fall into the following categories, each with different chemical resistance profiles. For compound details, see the materials guide. For cover options, see the backings and covers guide.
| Category | Materials | Chemical Strengths |
|---|---|---|
| Polyurethanes | PU 385, PU Yellow, D15, FDA1, FDA2, AU1, AU2 | Oils, greases, ozone, UV, most dilute acids |
| PVC covers | White Nub, Herringbone, Blue, Supergrip Green | Oil resistant, general chemical resistance |
| Nitrile rubber covers | Linatrile, NBR 65 | Fuels, solvents, hydraulic fluids, alcohols |
| Natural rubber covers | Linatex, RP 430, Supergrip | Abrasion resistance (limited chemical resistance) |
| PTFE (Teflon) covers | PTFE coating or tape | Nearly all chemicals, highest temperature resistance |
| Silicone covers | Silicone sheet bonding | High temperature, food-grade, moderate chemical resistance |
Tension Member Selection for Corrosive Environments
The tension member (cord) is protected by the polyurethane belt body, but if the belt edge is cut or the cord becomes exposed, corrosion can occur. Select the cord type based on your environment. For more detail, see the materials guide.
| Environment | Recommended Tension Member |
|---|---|
| Dry, non-corrosive | Standard high-carbon steel |
| Occasional moisture | Stainless steel |
| Continuous washdown | Sealed AU1 encapsulated cords or stainless steel |
| Chemical exposure (acids, solvents) | Stainless steel or aramid (Kevlar) |
Frequently Asked Questions
Standard polyurethane belts offer excellent resistance to mineral oils, greases, and most common lubricants. For heavy oil exposure, the AU3 compound provides enhanced oil and fat resistance. For applications where oil contacts the back side, oil-resistant PVC or nitrile covers are available.
Standard polyurethane is not recommended for prolonged solvent exposure (acetone, MEK, toluene, ethanol). For solvent environments, specify nitrile rubber (NBR) covers or PTFE (Teflon) covers over the polyurethane belt body. PTFE provides the broadest chemical resistance of any cover material.
Yes. Polyurethane is generally compatible with food-grade lubricants including mineral oil-based, PAO synthetic, and silicone-based food-grade oils. For direct food contact, ensure the belt material is also FDA-compliant (FDA1, FDA2, AU1, or AU2 compound).
Standard polyurethane offers good resistance to mineral-based hydraulic fluids for splash or intermittent contact. Prolonged immersion in synthetic hydraulic fluids (phosphate esters) may cause softening or swelling. For continuous hydraulic fluid exposure, specify nitrile or PTFE covers. Contact Texas Belting at 888-203-2358 with your specific fluid type for a compatibility assessment.
Exposure to incompatible chemicals can cause swelling, softening, hardening, cracking, or accelerated wear depending on the chemical type, concentration, temperature, and exposure duration. If you suspect chemical incompatibility, remove the belt from service and contact Texas Belting for material recommendations suited to your environment.
Stainless steel tension members are recommended whenever the belt is exposed to moisture combined with chemicals, acids, or salt. Standard steel cord is protected by the polyurethane body, but if the belt edge is cut or the cord becomes exposed through wear, stainless steel prevents corrosion failure. Sealed AU1 encapsulated cords provide the highest protection for washdown environments.
Yes. Texas Belting can provide sample belt and cover materials for you to test in your specific chemical environment. This is recommended whenever the chemical is not listed in the compatibility chart or when the exposure conditions (concentration, temperature, duration) are unusual. Call 888-203-2358 to request test samples.
Contact Texas Belting at 888-203-2358 with the specific chemicals, concentrations, temperatures, and exposure type (splash, intermittent, or continuous immersion). Our technical team will review compatibility data and recommend the optimal belt compound, cover material, and tension member for your application.
Need Chemical Compatibility Guidance?
Send us your chemical environment details. We will recommend the right belt compound, cover, and tension member combination.