Silicone Rubber Parts: Complete Guide to Material Properties, Manufacturing, and Applications (2026)

Silicone rubber stands apart from organic elastomers due to its unique silicon-oxygen backbone. This inorganic structure imparts exceptional temperature resistance, biocompatibility, and weatherability that make silicone the material of choice for medical devices, food processing equipment, aerospace components, and countless consumer products. Whether you’re specifying silicone O-rings for a pharmaceutical filling line or designing custom gaskets for outdoor electronics enclosures, this guide covers everything you need to select the right silicone compound and source quality parts from China. —

Table of Contents

1. What is Silicone Rubber? 2. Key Properties of Silicone 3. Types of Silicone Rubber 4. Silicone Material Grades 5. Chemical Resistance 6. Common Applications 7. Temperature and Hardness Options 8. Silicone vs. Other Elastomers 9. Manufacturing Processes 10. Food-Grade and Medical Compliance 11. How to Select a Supplier 12. Pricing and MOQ 13. FAQ 14. Conclusion —

What is Silicone Rubber?

Silicone rubber is a synthetic elastomer composed of silicon (a metalloid element) combined with oxygen, carbon, and hydrogen. Unlike organic rubber compounds derived from petroleum, silicone’s inorganic silicon-oxygen backbone (Si-O-Si) provides unique properties that organic rubbers cannot match.

Chemical Structure

The silicone polymer chain consists of: – Silicon-oxygen bonds (Si-O): Provide thermal stability and flexibility – Methyl groups (CH₃): Give silicone its hydrophobic character – Various substituents: Customize properties for specific applications

Key Characteristics

Characteristic	Benefit
Inert and non-toxic	Safe for food and medical contact
Extreme temperature range	-85°F to +450°F (-65°C to +232°C)
UV and ozone resistance	Excellent outdoor durability
Low compression set	Long-term sealing memory
Excellent electrical insulation	Dielectric properties up to 500V/mil

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Key Properties of Silicone

Silicone rubber offers a unique combination of properties that make it indispensable in many applications:

Property	Value	Significance
Temperature Range	-85°F to +450°F (-65°C to +232°C)	Widest operating range of common elastomers
Hardness	20-90 Shore A	From soft gels to firm seals
Tensile Strength	800-1,500 psi	Moderate strength
Elongation	100-700%	Highly flexible
Compression Set	10-25% (at 70h @ 175°C)	Good long-term seal memory
Ozone Resistance	Excellent	No cracking or degradation
UV Resistance	Excellent	Outdoor/long-term exposure
Electrical Insulation	Excellent	Dielectric strength 500-700 V/mil
Gas Permeability	Moderate	Lower than FKM but acceptable
FDA Compliance	Available	Food-contact grades

Advantages of Silicone

– ✅ Wide temperature range (lowest temperature capability of common elastomers) – ✅ Excellent biocompatibility (ideal for medical and food contact) – ✅ Non-reactive and hypoallergenic – ✅ Outstanding weather and UV resistance – ✅ Excellent electrical insulation properties – ✅ Soft durometer options available (20-30 Shore A for gels) – ✅ Tasteless and odorless

Limitations of Silicone

– ❌ Poor oil and fuel resistance (swells in petroleum products) – ❌ Lower tear strength compared to organic rubbers – ❌ Higher gas permeability than some elastomers – ❌ Moderate abrasion resistance – ❌ Higher cost than NBR or EPDM – ❌ Limited chemical resistance to acids and bases —

Types of Silicone Rubber

HCR (High Consistency Rubber)

Also known as ” gum stock” or “solid silicone,” HCR is the traditional silicone rubber requiring vulcanization (curing) at elevated temperatures. Characteristics: – Two-part platinum-catalyzed or peroxide-cured systems – Available in extruded profiles, molded parts, calendared sheets – Typical hardness: 30-90 Shore A – Good mechanical properties Applications: – Extruded seals and gaskets – Custom molded parts – Sheet gaskets and diaphragms

LSR (Liquid Silicone Rubber)

LSR is a two-component platinum-catalyzed system that remains liquid at room temperature, enabling high-speed injection molding. Characteristics: – Extremely pure and consistent – Rapid cure times (seconds to minutes) – Flash-free molding – Excellent for high-volume production – Typical hardness: 20-70 Shore A Applications: – Medical devices and components – Baby care products (nipples, soothers) – Pharmaceutical closures – High-precision electronic components Advantages of LSR: – Very low flash and waste – Excellent reproducibility – Ideal for cleanroom manufacturing – Cost-effective at high volumes

RTV (Room Temperature Vulcanizing)

RTV silicone cures at room temperature without requiring heat press. One-Part RTV: – Moisture-cure systems (acetoxy, neutral cure) – Skin formation in 5-30 minutes – Full cure in 24-72 hours Two-Part RTV: – Platinum-catalyzed or tin-catalyzed – Mix and pour systems – Adjustable pot life and cure time Applications: – Prototyping and low-volume production – Sealants and adhesives – Mold making – Potting and encapsulation

FVMQ (Fluorosilicone)

Fluorosilicone combines silicone’s temperature resistance with improved fuel and oil resistance. Characteristics: – 40-60% fluorine content – Temperature range: -75°F to +350°F (-59°C to +177°C) – Improved oil and fuel resistance vs. standard silicone – More expensive than standard silicone Applications: – Aerospace fuel system seals – Automotive fuel handling – Marine applications —

Silicone Material Grades

General Purpose Silicone

– Temperature: -55°F to +400°F (-48°C to +204°C) – Applications: Seals, gaskets, general-purpose molding – Cost: $$

High-Temperature Silicone

– Temperature: -55°F to +500°F (-48°C to +260°C) – Special compounds: Enhanced thermal stability – Applications: Oven seals, high-temp processing – Cost: $$$

Low-Temperature Silicone

– Temperature: -130°F to +350°F (-90°C to +177°C) – Special compounds: Flexible at cryogenic temperatures – Applications: Aerospace, cryogenic equipment – Cost: $$$

High-Strength Silicone

– Tensile strength: Up to 2,000 psi – Enhanced tear resistance – Applications: Extrusions, shapes requiring durability – Cost: $$$

Wire and Cable Silicone

– Enhanced electrical properties – UL-rated compounds available – Applications: Wire insulation, cable jackets – Cost: $$$

Conductive Silicone

– Electrically conductive fillers (carbon, silver, nickel) – Volume resistivity: 1-100 ohm-cm – Applications: EMI shielding, static discharge – Cost: $$$$

Electrically Insulating Silicone

– Dielectric strength: Up to 700 V/mil – Applications: High-voltage insulation – Cost: $$$ —

Chemical Resistance

Excellent Resistance ✓

– Water (hot and cold) – Steam (up to 250°F / 121°C) – Animal and vegetable oils – Ozone and weathering – dilute acids and alkalis – Silicone oils and greases – Many solvents (alcohol, glycols)

Limited/Poor Resistance ✗

– Petroleum oils and fuels (swells significantly) – Aromatic solvents (toluene, benzene) – Chlorinated solvents – Ketones (MEK, acetone) – Concentrated acids – Steam above 250°F (degrades) ⚠️ Warning: Never use silicone in contact with petroleum oils or fuels. For oil-resistant applications, consider FKM (Viton®) or NBR (Nitrile). —

Common Applications

Medical and Healthcare

– Syringe plungers and stoppers – IV catheter access ports – Reservoir diaphragms – Wound care components – Implantable device components (with special biocompatibility) – Surgical instrument grips

Pharmaceutical

– Stopper and closure systems – Peristaltic pump tubing – Container sealing systems – Aseptic processing components

Food and Beverage

– Beverage dispensers (coffee, soda) – **Bakery and confectionery molds – Dairy processing seals – Food conveyor components – Oven and freezer gaskets

Automotive

– Engine cooling system seals – **HVAC gaskets and seals – Sensor housings – **Lighting seals – Battery vent membranes

Electronics

– Outdoor enclosure gaskets – LED lighting seals – Printed circuit board coatings – Connector seals

Aerospace and Defense

– cockpit window seals – Fluid system seals – Thermal insulation – Vibration dampening

Consumer Products

– Kitchenware (spatulas, seals) – Baby products (nipples, soothers) – Watch bands and wearables – Sport equipment grips —

Temperature and Hardness Options

Maximum Service Temperature

Grade	Continuous	Intermittent
Standard	400°F (204°C)	450°F (232°C)
High-temp	500°F (260°C)	550°F (288°C)
Special	600°F (315°C)	650°F (343°C)

Minimum Service Temperature

Grade	Minimum
Standard	-55°F (-48°C)
Low-temp	-130°F (-90°C)
FLUOROSILICONE	-75°F (-59°C)

Hardness (Durometer) Options

Shore A	Typical Applications
20-30	Gel-like, very soft seals
40-50	Soft seals, medical components
50-60	General-purpose molding
60-70	Standard seals and gaskets
70-80	Higher strength requirements
80-90	Industrial applications, rollers

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Silicone vs. Other Elastomers

Best choice for: – Extreme low-temperature applications → Silicone – High-temperature oil exposure → FKM – Outdoor weathering → Silicone or EPDM – Food/medical contact → Silicone – Cost-effective oil resistance → NBR—Manufacturing ProcessesInjection Molding (LSR)– Best for: High volume, medical/food grade – Tolerance: ±0.003″ to ±0.010″ – Tooling Cost: $10,000-$100,000 – Per-part Cost: Low at volume – Cycle Time: 10-60 seconds – Typical MOQ: 5,000-50,000 piecesCompression Molding (HCR)– Best for: Low-medium volume, large parts – Tolerance: ±0.005″ to ±0.020″ – Tooling Cost: $500-$10,000 – Per-part Cost: Moderate – Typical MOQ: 100-1,000 piecesTransfer Molding– Best for: Insert molding, medium volume – Tolerance: ±0.005″ to ±0.015″ – Tooling Cost: $2,000-$20,000 – Per-part Cost: Moderate – Typical MOQ: 500-5,000 piecesExtrusion– Best for: Continuous profiles, tubing – Tolerance: ±0.010″ to ±0.030″ – Tooling Cost: $1,000-$15,000 – Per-part Cost: Low – Typical MOQ: 500-5,000 metersCalendering– Best for: Sheet, film, die-cut parts – Tolerance: ±0.005″ to ±0.020″ – Width: Up to 60″ – Typical MOQ: 100-500 kg—Food-Grade and Medical ComplianceFDA ComplianceFDA 21 CFR 177.2600 – Rubber articles intended for repeated food contact: – Specific extraction testing required – Common for food-processing seals – Typical color: Translucent or specific food-grade colorsFDA 21 CFR 177.1550 – Silicone rubber polymers: – For direct food contact – Extraction testing with food simulantsMedical ComplianceUSP Class VI – Biological reactivity testing: – Class VI-A: In Vivo implantation test (subcutaneous) – Class VI-B: Intracutaneous test – Class VI-C: Systemic injection testISO 10993 – Biocompatibility testing: – Cytotoxicity testing – Sensitization testing – Irritation testing – Implantation testing3-A Sanitary Standards– 3-A Sanitary Standard 18-03:蠕虫蠕动泵用弹性体组件 – Compliance for dairy and food processing—How to Select a SupplierWhen sourcing silicone parts from China:1. Compound Verification– Request compound data sheets – Verify FDA or USP compliance with certificates – Conduct incoming inspection and testing2. Manufacturing Capabilities– LSR injection molding for medical/food grade – Cleanroom facilities for medical – Compression and transfer molding for custom parts – Extrusion for profiles3. Quality Certifications– ISO 9001:2015 minimum – ISO 13485 for medical devices – GMP (Good Manufacturing Practice) – FDA registration for food/medical4. Testing Capabilities– Physical property testing – FDA extraction testing (if required) – USP Class VI testing (via third-party labs) – Dimensional inspection reports5. Sample and Prototyping– Sample availability for validation – Rapid prototyping for new designs – Technical support for DFM (Design for Manufacturability)Red Flags ⚠️– Unable to provide FDA/USP documentation – No sample policy – Very low prices (may indicate non-compliant materials) – Limited communication – No quality certifications—Pricing and MOQPrice Factors1. Compound type (standard vs. special) 2. Compliance requirements (FDA, USP Class VI) 3. Order volume 4. **Part complexity and tolerance 5. Tooling requirementsTypical Pricing (USD per piece)

Property	Silicone	FKM	EPDM	NBR
Temp Range	-85 to +450°F	-20 to +400°F	-65 to +300°F	-40 to +250°F
Oil Resistance	Poor	Excellent	Poor	Good
Weather Resistance	Excellent	Excellent	Excellent	Fair
Steam Resistance	Good (≤250°F)	Poor	Good	Poor
FDA Compliance	Excellent	Limited	Limited	No
Cost	$$$	$$$$	$$	$
Biocompatibility	Excellent	Good	Fair	Fair

Note: Food-grade and medical-grade compounds command premium pricing.MOQ Expectations– Standard O-rings: 100-1,000 pieces – Custom LSR molding: 5,000-25,000 pieces – Custom compression molding: 200-1,000 pieces – Extruded profiles: 500-2,000 meters—FAQQ: Can silicone be used in steam applications?A: Yes, but with limitations: – Standard silicone: Up to 250°F (121°C) steam – Special steam-resistant grades: Up to 350°F (177°C) – For higher temperatures, consider PTFE or graphite-filled siliconeQ: What’s the shelf life of silicone parts?A: Silicone has excellent aging resistance: – Typical shelf life: 10-20+ years – Storage: Cool, dry, away from ozone and chemicals – No significant hardening or cracking with proper storageQ: Is silicone hypoallergenic?A: Yes, silicone is: – Non-reactive with body tissues – Hypoallergenic (rarely causes allergic reactions) – Widely used in medical and baby care products – Odorless and tastelessQ: Can silicone withstand robot vacuum conditions?A: For robotic applications, consider: – Silicone gaskets with metal inserts – Custom molded parts with enhanced tear strength – Silicone-rolls for continuous operation – Our team can recommend compounds for specific robotic environmentsQ: What’s the difference between LSR and HCR silicone?A: Key differences:

Part Type	1,000 pcs	10,000 pcs	50,000 pcs
Simple O-ring	$0.10-0.30	$0.05-0.15	$0.03-0.10
Custom Gasket	$0.50-2.00	$0.30-1.00	$0.20-0.60
LSR Medical Part	$0.20-1.00	$0.10-0.50	$0.05-0.30
Extruded Profile	$0.50-2.00/m	$0.30-1.00/m	$0.20-0.50/m

Aspect	LSR	HCR
Form	Liquid, two-component	Solid gum stock
Processing	Injection molding	Compression/transfer
Purity	Very high	Standard
Volume	High volume	Low-medium volume
Cost at volume	Lower	Higher

FlashMinimalRequires finishing

Q: Can silicone be colored?

A: Yes: – Standard colors: Translucent, red, black, white – Custom colors: Available with pigment additives – FDA colors: Specific colorants approved for food contact —

Conclusion

Silicone rubber’s unique properties—inertness, extreme temperature range, biocompatibility, and weather resistance—make it the material of choice for demanding sealing applications in medical, pharmaceutical, food processing, aerospace, and consumer products. When sourcing silicone parts from China, partner with suppliers who offer: – Validated compound compliance (FDA, USP Class VI, ISO 10993) – Cleanroom manufacturing for medical-grade parts – Quality certifications (ISO 9001, ISO 13485) – Technical support for material selection and DFM Need custom silicone parts from a reliable China manufacturer? 👉 Request a Quote → Our team specializes in LSR injection molding and custom silicone components for medical, food, and industrial applications. Response within 24 hours with DFM feedback. — Related Guides: – The Complete Guide to Custom Rubber Gaskets – Material selection and manufacturing overview – FKM/Viton Rubber: Properties and Applications – High-temperature chemical-resistant seals – NBR Rubber: Oil-Resistant Solutions – Cost-effective oil-resistant seals — This guide is for informational purposes. Consult with our engineering team for application-specific recommendations.