What Is Low-Phenyl Silicone Rubber Compound?
Low-phenyl silicone rubber compound is a heat-curing elastomer compound prepared by mixing methyl vinyl phenyl silicone rubber gum with reinforcing fillers such as fumed silica, heat-resistant additives and organic peroxide curing agents. Compared with ordinary methyl vinyl silicone rubber compounds, it introduces a moderate amount of phenyl groups into the polymer backbone, disrupting the regularity of siloxane chains and reducing low-temperature crystallization, thereby achieving superior cold resistance.
The product is typically supplied as milky white or translucent compound blocks. It can be transported as a non-dangerous chemical and should be stored sealed, protected from light, and kept away from curing agents, acids, bases and oils.
Key Technical Indicators
Phenyl Content
Phenyl content is the most important structural parameter for low-phenyl silicone rubber compound. When phenyl content is in the range of 5%-15%, the hardening temperature can drop below -115°C, and the material maintains flexible elasticity at -70°C to -100°C, making it one of the best cold-resistant rubbers available. Too low phenyl content provides limited low-temperature improvement; too high increases chain rigidity, reduces low-temperature elasticity and makes processing more difficult.
Hardness
Common hardness ranges from 30 to 80 Shore A, customizable for compression-molded seals, extruded profiles or damping components. Lower hardness grades suit applications requiring good conformity and low compression force; higher hardness grades suit structural parts needing higher load-bearing capacity and dimensional stability.
Tensile Strength and Elongation
Typical tensile strength is about 5-12 MPa, with elongation at break around 150%-500%, depending on gum molecular weight, filler type and curing process. At low temperatures, volume shrinkage effects can increase tensile strength and elongation; tensile strength may reach around 22 MPa at -70°C.
Compression Set
Cured low-phenyl silicone rubber compound exhibits low compression set, especially maintaining good elastic recovery and sealing performance at low temperatures, making it suitable for aerospace door seals, window seals and low-temperature pipeline sealing.
Damping and Vibration Isolation
The introduction of phenyl groups improves shear modulus stability across a wide temperature range, giving low-phenyl silicone rubber relatively stable shear performance from -70°C to 60°C and good damping characteristics, suitable for damping pads in high-speed rail, aircraft and new energy vehicles.
Radiation and Ablation Resistance
While radiation resistance is most prominent in high-phenyl silicone rubber, low-phenyl grades also offer certain radiation and ablation resistance, suitable for some aerospace and electronics applications under extreme conditions.
Appearance and Storage
The product is usually a milky white or translucent uniform compound block. It should be stored sealed, protected from light, in a cool, dry and ventilated place, away from heat sources, curing agents and organic solvents. Shelf life is generally no more than 12 months.
Main Performance Features
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Excellent cold resistance: 5%-15% phenyl content, hardening temperature as low as -115°C, flexible at -100°C.
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Stable wide-temperature elasticity: combines silicone rubber's high/low temperature resistance, aging resistance and vibration damping.
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Low compression set: good elastic recovery for low-temperature sealing.
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Good damping properties: stable shear modulus across wide temperature range, suitable for vibration isolation.
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Certain radiation and ablation resistance: usable in aerospace and electronics extreme environments.
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Versatile processing: suitable for compression molding, extrusion and injection molding into seals, gaskets, tubes and rods.
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Non-dangerous transport: convenient for sample delivery and overseas customer trials.
Typical Application Scenarios
Aerospace Low-Temperature Seals
Low-phenyl silicone rubber compound can be compression-molded into seals, gaskets and O-rings for aircraft doors, windows, fuel lines and hydraulic systems in extreme cold environments, maintaining elasticity and sealing force at -100°C.
Electronics Low-Temperature Damping Parts
Suitable for damping pads, buffer blocks and sealing strips in electronic equipment, applicable to polar expedition equipment, low-temperature storage facilities and outdoor communication base stations.
Automotive and New Energy Vehicle Sealing and Damping
Ideal for new energy vehicle battery pack seals, engine low-temperature pipeline gaskets and body damping pads, maintaining stable performance in extremely cold winter regions.
Low-Temperature Tubes and Rods
Can be extruded into cold-resistant tubes and rods for low-temperature fluid transfer, laboratory cryogenic equipment and structural support under special conditions.
High-Speed Rail and Rail Transit Dampers
With good damping characteristics and wide-temperature stability, suitable for high-speed rail bogie damping pads, car body buffers and track sealing components.
New Energy and Wind Power Sealing
Suitable for sealing and damping components in wind turbines under low-temperature outdoor conditions, maintaining reliable performance during temperature cycling.
Selection and Usage Recommendations
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Select by phenyl content: for extreme cold resistance, choose 5%-10% phenyl content; for balanced ablation or radiation resistance, consider medium- or high-phenyl compounds, noting increased processing difficulty.
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Match hardness to application: 30-60 Shore A for seals; 60-80 Shore A for structural support.
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Confirm curing system: organic peroxide curing requires controlled temperature, time and post-cure conditions to avoid under-cure or over-cure.
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Observe storage conditions: store sealed, protected from light, away from curing agents and heat; check for surface skinning or hardening before use.
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Run small-scale trials first: low-temperature tensile, compression set and damping performance vary by formulation, so compression or extrusion trials are recommended.
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Key points for overseas customers: highlight -100°C cold resistance, low compression set, compression/extrusion versatility and non-dangerous transport to facilitate sample delivery and technical discussion.
Phenyl silicone rubber IOTA BHTV 3830 series
