Common Materials Used In Rubber Molding

Introduction

Picking the right material is the most important decision when making high-performance parts. Whether you need seals that handle extreme heat, gaskets that fight off chemical damage, or vibration dampers that take constant movement, the base rubber makes or breaks the part.

The rubber molded products come with dozens of elastomer options. Each one behaves differently with heat, pressure, and chemicals. Take natural rubber—it's flexible. Fluorocarbon? That one can work with harsh fluids. Get to know these materials, and your parts won't just tick boxes—they'll survive a real working environment.

Here, we will discuss the most common rubber molding materials, their strengths, weaknesses, and typical applications.
 

1. Natural Rubber (NR): The Versatile Material

Natural rubber has great tear strength, flexibility, and the ability to absorb shocks. That's why it works so well for engine mounts, conveyor belts, and tire parts. In rubber molding products, natural rubber gives you good strength and low heat build-up under repeated stress.

The downsides: it works poorly with oils, fuels, and ozone. Its usable temperature range is -50°C to +80°C. For parts that see petroleum-based fluids, pick a synthetic alternative. KRISHANI often suggests natural rubber for farm equipment, vibration pads, and shoe soles when customers want low cost and high resilience above all else.

2. Styrene-Butadiene Rubber (SBR): The Wear-Resistant Material

SBR is the most commonly made synthetic rubber out there. It was first designed as a substitute for natural rubber. It gives you better resistance to abrasion, aging, and water. You'll see it in tire treads, floor mats, and conveyor rollers. In rubber component manufacturing, SBR really shines when you're watching your budget and need parts to last.

The downsides: It doesn't handle oil or fuel well, and it gets only moderately flexible in the cold. If you need custom rubber molding services for high-traffic parts like washing machine gaskets or car seals, SBR saves you money. KRISHANI often processes SBR for industrial wipers, brake diaphragms, and shoe soles—anywhere surfaces rub together repeatedly.

3. Nitrile Rubber (NBR)

Nitrile rubber (acrylonitrile-butadiene copolymer) is what most people use when they need fuel and oil resistance. By changing the acrylonitrile (ACN) content from 18% to 50%, makers can balance flexibility against chemical resistance. High-ACN grades stand up to aromatic hydrocarbons.

Low-ACN ones stay flexible down to -40°C. Typical rubber molded products from NBR include O-rings, fuel hoses, oil seals, and hydraulic system parts. But NBR doesn't work well in ozone-rich environments, with glycol-based brake fluids, or in heat above 120°C.

If you need both oil resistance and low-temperature flexibility, hydrogenated NBR (HNBR) is a step up. As custom rubber manufacturers, KRISHANI helps clients pick the right ACN level for fuel injection seals, blowout preventers, and industrial rollers that see petroleum every day.

4. EPDM Rubber: The Weatherproof Expert

Ethylene Propylene Diene Monomer (EPDM) rules outdoor and high-temperature uses. Its resistance to ozone, UV, steam, and weather is hard to beat. It also handles polar fluids (brake fluids, acids, alkalis) well. Typical uses include roofing membranes, window seals, radiator hoses, and electrical insulation. For elastomer-molded products requiring decades of outdoor life, EPDM is often the material of record.

Weaknesses include poor resistance to petroleum oils, gasoline, and hydrocarbon solvents. Its high tear strength and flexibility from -50°C to +150°C make it ideal for automotive weatherstripping. KRISHANI has delivered thousands of EPDM-based custom rubber molding projects for HVAC systems, pool pump gaskets, and solar panel mounts. If your part will work in sun, rain, or steam, EPDM is your choice.

5. Silicone Rubber (VMQ/PVMQ): Extreme Temperature Expert

Silicone rubber stands alone when it comes to heat and cold stability. It runs continuously from -60°C to +230°C, and briefly up to 300°C. It stays flexible at very low temperatures, resists compression set, and has excellent dielectric properties. Common rubber molding products from silicone include medical tubing, baking mats, keypads, and aerospace seals. Food-grade and medical-grade versions are easy to find.

The downsides: poor tensile strength, high cost, and weakness against oils, fuels, and steam under pressure. Silicone also lets gas through, so it's not good for high-vacuum seals without reinforcement. In rubber component manufacturing for pharmaceutical or food processing, KRISHANI uses platinum-cured silicone to keep things pure and compliant. We also help clients decide between silicone and fluorosilicone (which adds fuel resistance).

6. Fluoroelastomer (FKM/Viton)

FKM rubbers (often called Viton™) resist more chemicals than any other elastomer. They handle aggressive fuels, acids, chlorinated hydrocarbons, and hot oil up to 250°C nonstop. Typical applications include aircraft engine seals, chemical plant gaskets, and automotive fuel system components. For rubber molded products exposed to jet fuel, hydraulic fluid, or solvent blends, FKM is unmatched.

The downsides are high cost, poor low-temperature flexibility (standard grades stiffen below -15°C), and difficult processing. At KRISHANI, we mold FKM into precision O-rings, shaft seals, and downhole tool parts for oil and gas customers. We also help buyers weigh FKM against cheaper options like NBR when the chemicals aren't so harsh.

7. Neoprene (CR): The Balanced All-Rounder material

Chloroprene rubber (CR), or neoprene as it's usually called, gives you moderate oil resistance along with excellent protection from weather, ozone, and flames. It outlasts natural rubber and beats EPDM on mechanical strength in some situations where oil is involved. Typical uses: wetsuits, cable jackets, bridge bearings, and adhesive formulas.

As a rubber molding material, neoprene is a popular choice when you want a balanced set of properties—not top in any one category, but reliable in many. The Limitations? It works poorly with aromatic fuels, and its temperature range is -35°C to +120°C. Neoprene also has a higher specific gravity (1.23 g/cm³) than many rubbers, making parts heavier.

KRISHANI frequently recommends neoprene for industrial belts, automotive hose covers, and marine fenders where both oil splash and saltwater exposure occur daily.

8. Polyurethane (PU)

Polyurethane elastomers sit somewhere between rubber and plastic. They give you outstanding resistance to cuts, tears, and abrasion—often five to ten times better than natural rubber. Polyurethanes come in castable, thermoplastic, and millable versions, each one suited to different custom rubber moulding processes.

Typical applications include forklift tires, screen printing squeegees, hydraulic seals, and mining screens. Disadvantages include poor high-temperature performance (above 80°C for most grades), susceptibility to hydrolysis (moisture attack), and difficult mold release. For elastomer-molded products that slide against abrasive surfaces—like conveyor scrapers or pump impeller liners—polyurethane is often the only economic choice.

At KRISHANI, we partner with clients to select polyester or polyether-based PU for the right level of moisture resistance. We also recommend processing practices that prevent bubble formation during injection molding.

Why Material Selection Matters for Your Industry

The wrong elastomer causes early cracking, swelling, hardening, or chemical melting. Every part that fails leads to downtime, warranty issues, and damage to your product reputation. A smart custom rubber molding services provider helps you get the balance right.

KRISHANI works with 30 rubber compounds, including unique blends with PTFE, carbon fiber, or graphite to lower friction. We also consider how easy the material is to mold: some rubber molding materials (like high-durometer silicone) need special release agents, and fluoroelastomers need heated runner systems.

Our engineering team designs molds and processes based on the material's flow, giving you zero flash, full cavity fill, and even curing.

Conclusion

Getting good at rubber molding materials turns a standard part into a real edge over competitors. From natural rubber's flexibility to FKM's chemical defense, each elastomer has its own properties. We've covered eight major materials—NR, SBR, NBR, EPDM, silicone, FKM, neoprene, and PU—along with what they're good at, where they fall short, and what they're best used for.

Whether you need elastomer-molded parts for medical equipment or heavy-duty rubber molded parts for mining equipment, the right material exists. Being a full-service rubber component manufacturer means KRISHANI does more than make parts.

We suggest which materials to use, develop custom compounds, design molds, and run tight quality checks. We're after your long-term success, not just a single shipment. We've helped hundreds of engineers reduce failures, lower costs, and get to market faster by making smart material choices.

Contact KRISHANI

With the right advanced materials and precise rubber molding techniques, your next project becomes a lot easier to execute

Call +1 (647) 294-5240 or email info@krishani.com.
At KRISHANI, we deliver dependable rubber-shaped answers, custom rubber forming, and elastomer molded pieces to fit many kinds of industrial needs.

FAQ

1. What materials are used in rubber molding?

The materials which you will encounter most frequently include Natural Rubber (NR), SBR, NBR, Silicone (VMQ), EPDM, FKM, and TPE. The appropriate selection depends on the necessary flexibility and durability requirements of your rubber-molded product. KRISHANI's custom rubber molding services provide expert assistance for making that selection.

2. How do additives improve rubber materials?

Elastomer molded products from custom rubber molding get a performance boost with additives like plasticizers, antioxidants, UV stabilizers, and colorants.

3. Which industries use custom rubber molding?

Custom rubber moulding shows up across many different industries. Car and airplane makers use it. So do medical equipment companies and consumer goods manufacturers. It's a go-to choice to make seals, gaskets, hoses, and plenty of other rubber-molded parts.