| HS Code | 701496 |
| Hardness Shore A | 30–50 |
| Density G Cm³ | 1.10–1.15 |
| Tensile Strength Mpa | 6–10 |
| Elongation At Break | 300–600 |
| Tear Strength Kn M | 20–40 |
| Compression Set | 10–30 |
| Linear Shrinkage | 1.5–3.0 |
| Viscosity Mpa S | 50,000–200,000 |
| Pot Life H | 24 |
| Curing Temperature C | 120–170 |
| Curing Time Min | 5–15 |
| Service Temperature Range C | -50 to 200 |
| Color | Translucent/white |
| Appearance | Pasty liquid |
As an accredited Liquid silicone rubber for Scutcheon RH-G3 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packed in 20 kg sealed plastic pails, labeled Liquid Silicone Rubber for Scutcheon RH-G3 for safe storage and transport. |
| Container Loading (20′ FCL) | 20′ FCL loaded with Liquid silicone rubber for Scutcheon RH-G3, securely palletized, sealed, and shipped with proper chemical transport documentation. |
| Shipping | Liquid silicone rubber for Scutcheon RH-G3 is generally non-hazardous and not regulated for transport (no UN number). Ship in original, sealed, labeled containers; protect from heat, sunlight, moisture, and contamination. Store cool, dry, well-ventilated. Handle with standard PPE and avoid spills. |
| Storage | Storage for Liquid silicone rubber for Scutcheon RH-G3: Store in a cool, dry, well-ventilated area away from direct sunlight, heat sources, sparks, and incompatible materials such as strong oxidizers, acids, and alkalis. Keep containers tightly closed, upright, clearly labeled, and in original packaging. Protect from moisture and contamination. Avoid freezing. Follow local regulations and manufacturer’s SDS recommendations. |
| Shelf Life | Typically 12 months from date of manufacture when stored unopened in original packaging at 5–25°C, protected from moisture and direct sunlight. |
Automotive exterior scutcheon plates of RH-G3 are processed on an all-electric liquid silicone rubber injection-moulding platform with closed-loop shot-weight control and a cold-runner block held at 18–25 °C. A 30–40 mm plasticising screw with an L/D ratio of 18:1–22:1 and a static mixer mounted downstream of the metering pump are standard on production lines. The A and B components are metered at a 1:1 volumetric ratio; inorganic pigment masterbatch is dosed into the base at 1.5–3.0 wt%, and a silane-type adhesion promoter is added at 0.5–1.0 wt% when the scutcheon is overmoulded onto ABS or PC/ABS. Substrate pre-treatment is verified by dyne pen at 38–44 mN/m. Cure is run at 120–160 °C for 45–90 s; thicker emblem ribs above 1.5 mm require extension to 120 s. Exterior OEM validation normally references ISO 37:2017 tensile strength, ISO 7619-1:2010 Shore A hardness of 40–60, ISO 34-1:2022 tear strength, ISO 815-1:2014 compression set at 70 °C/22 h, and SAE J2527:2017 xenon-arc weathering for exterior grade. Hazardous substance screening is documented against REACH EC 1907/2006 SVHC and RoHS Directive 2011/65/EU Annex II. The output covers trunk-lid nameplates, grille badges, wheel centre caps, side-fender scutcheons, and charge-port identity plates. On black ABS carriers stored above 60% RH, pre-drying of the substrate is mandatory before moulding; residual moisture causes interfacial splay and reduces liner adhesion. Batch-to-batch viscosity drift of ±5% in either component has been associated with gate pressure fluctuation of 8–12% and flash formation at the parting line when dynamic injection pressure exceeds 25–30 MPa.
Wearable device scutcheons and backlit logo plates place a narrower thermal ceiling on RH-G3 than automotive trim because polycarbonate inserts begin to stress-relax above 125 °C. The process uses pre-formed 0.3–0.5 mm polycarbonate films screen-printed with UV-cured ink, then inserts them into a valve-gated LSR tool under vacuum of −80 kPa or lower. For translucent and backlit designs, the pigmented masterbatch addition is reduced to 0.05–0.2 wt% to maintain light transmittance; a light-diffusing polysiloxane microsphere additive may be incorporated at 0.1–0.5 wt%, while a blue-light absorbing additive is dosed at 0.02–0.08 wt% when the LED source has a colour temperature above 6500 K. The A/B metering ratio is maintained at 1:1; adhesion promoter on the insert is limited to 0.2–0.5 wt% to prevent visible edge bloom around the logo. Curing takes place at 110–125 °C for 60–90 s, with the lower temperature extended to 120 s for parts overmoulding stainless-steel antenna rings. Product safety compliance follows IEC 62368-1:2023 for portable electronic equipment, and skin-contact biocompatibility is assessed under ISO 10993-5:2009 and ISO 10993-10:2021 for earbud and smartwatch body-contact surfaces. Restricted substances are screened against RoHS Directive 2011/65/EU Annex II and REACH EC 1907/2006. Finished types include smartwatch crown surrounds, wireless earbud stem badges, wearable optical sensor covers, and backlit phone logo plates. Operational limits include an upper mould temperature of 130 °C: beyond this, microcracking and birefringence around the gate become visible in polarised-light inspection. Vacuum levels below −60 kPa produce trapped air pockets at the ink–silicone interface; conversely, vacuum above −95 kPa can draw low-viscosity LSR into micro-vent channels.
Medical device faceplates and sealed interface scutcheons based on RH-G3 are produced in an ISO 14644-1:2015 Class 7 cleanroom on an all-electric LSR injection machine with stainless-steel platens and a valve-gated cold runner. The cured article is tested under ISO 10993-5:2009 for cytotoxicity and ISO 10993-10:2021 for skin sensitization and irritation; raw material biological reactivity is certified to USP <87> and USP <88>. The quality system is maintained to ISO 13485:2016, and when the faceplate may be touched during food preparation in hospital kitchens, incidental food-contact compliance is supported by FDA 21 CFR 177.2600. For addition ratio, RH-G3 is metered at 1:1 A/B, and the platinum-catalysed system contains no peroxide; high-purity phthalocyanine or carbon black masterbatch is restricted to 0.05–0.2 wt% to preserve clean-room particulate limits and sterilizability. Radiopaque faceplates require barium sulphate at 15–25 wt%, which lowers tensile strength and tear resistance and must be compensated by increasing part thickness by 0.2–0.5 mm. The production process includes insert moulding of medical-grade polycarbonate or PBT substrates, mould temperature 140–160 °C, cure 60–120 s, and post-cure at 150–180 °C for 2–4 h to reduce volatile cyclic siloxanes below validated limits. Terminal parts include handheld diagnostic keypads, infusion pump control-panel gaskets, ultrasonic scanner button arrays, and surgical instrument identification plates. A known limitation is platinum catalyst poisoning on contact with sulfur-containing substrate additives, organotin-catalysed silicones, or natural rubber gloves in handling; direct handling requires nitrile gloves and substrate lot testing before production.
The substitution of thermoset urethane with RH-G3 in outdoor identity plates is driven by yellowing resistance and compression set after thermal cycling. Exterior durability is verified by ASTM G154-23 UVA-340 weathering for 1000–2000 h and ISO 105-B02:2014 blue wool lightfastness of at least 7; enclosure protection follows IEC 60529:2013, with IP67 as the minimum and IP69K required for high-pressure washdown applications. Opaque outdoor scutcheons use an inorganic pigment masterbatch at 2.0–4.0 wt%, and laser-markable plates require 0.5–1.5 wt% of a laser-sensitive additive that chars locally under 1064 nm fibre-laser marking. The A/B component ratio is maintained at 1:1. In production, anodised aluminium or stainless-steel identification foils are placed into the tool and RH-G3 is injected around the perimeter as a bezel and sealing gasket; mould temperature is 140–170 °C, cure time is 75–120 s, and a post-cure at 180 °C for 1 h completes crosslinking. Because the linear thermal expansion of cured silicone is higher than aluminium, a minimum 0.1–0.2 mm clearance is maintained around rigid inserts to avoid edge cracking during thermal shock tests. Terminal products include industrial equipment rating plates, marine switch labels, valve identification tags, outdoor warning plates, and telecommunication enclosure badges. The limitation for this sector is chemical resistance: RH-G3 is not recommended for identity plates immersed in gasoline, diesel, or chlorinated cleaning solvents; if solvent contact is expected, a fluorosilicone capping layer or alternative grade should be specified. Published data for the exact RH-G3 swelling ratio under cyclic washdown with alkaline detergents is limited; validation under IEC 60529 conditions is therefore required before series release.
Appliance control-panel scutcheons made from RH-G3 are produced by multi-shot injection in which the first shot fills the glass-fibre reinforced polyamide or PBT frame and the second shot overmoulds the silicone keymat and display seal. This technique is used instead of mechanical assembly to eliminate panel-to-cabinet leak paths and to damp sound transmission. Compliance for household electrical safety is verified under IEC 60335-1:2020; food-contact surfaces adjacent to the control panel are assessed under FDA 21 CFR 177.2600 for repeated food exposure and EU 10/2011 overall migration when the appliance is used in food preparation. Addition ratio for the appliance sector uses a pigment masterbatch loading of 1.0–2.5 wt% in the base component, with the A/B ratio fixed at 1:1; for transparent or high-gloss display windows, no filler-based matting agent is used, and the addition of a thermally stable polydimethylsiloxane wetting agent is held below 0.2 wt%. The mould temperature is set to 130–160 °C with cure times of 60–100 s; cavity vacuum is maintained at −60 to −90 kPa to prevent air traps around tactile domes and light-guide recesses. Terminal parts include oven control knob grip rings, washing machine display seals, dishwasher button mats, cooktop light lens gaskets, and vacuum cleaner handle scutcheons. The principal operational boundary is oil swelling: repeated contact with cooking oils or butter on range control surfaces may produce volume swell of 3–8% and reduce tear strength. High-grease zones should use a fluorosilicone overmould or a barrier membrane; otherwise, the LSR scutcheon is limited to low-oil control environments.
Industrial membrane-style keypads using RH-G3 as the overmoulded silicone top layer differ from consumer keypads because the flexible circuit substrate and the LSR shrink at different rates after moulding. The keypad array is first printed with conductive silver or carbon traces on 0.125–0.250 mm PET or 0.05–0.1 mm polyimide film, then placed into a tool where RH-G3 is injected through a film edge gate to avoid disturbing the circuit layout. The A/B ratio is 1:1; a conductive carbon black masterbatch at 2.0–5.0 wt% is used only where the silicone must form electrically conductive contact pills bonded to the substrate, while a non-conductive outer matting agent at 0.3–1.0 wt% reduces surface tack on the keypad. Cure is run at 150–180 °C for 45–75 s; vacuum is controlled to −80 kPa because lower vacuum leaves air voids between the silicone and PET film, and higher vacuum pulls flash into micro-vent grooves. Compliance is tested under IEC 60529:2013 IP65 or IP67, ISO 20653:2013 when the keypad is mounted on road vehicles, and ASTM D2240-15(2021) for post-cure hardness; cure kinetics are verified by rotorless curemeter per ISO 6502-1:2018. For use in potentially explosive atmospheres, the assembled keypad is assessed under EN 60079-0:2018; the silicone component alone does not constitute certification. Finished types include agricultural machinery control panels, handheld industrial remote switches, food-processing touch surfaces, and explosion-proof keypads. Dimensional audit after 48 h post-mould ageing is required because post-cure shrinkage of the LSR can reach 2.5–3.0%, which shifts key dome position relative to the circuit contact. If shrinkage exceeds this range, tool compensation is revised before mass production. Batch acceptance includes an inhibition check when a new PET film lot or silver paste is introduced, as sulfur-containing additives in the film can poison the platinum catalyst and produce sticky, incomplete cure at the interface.
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Liquid silicone rubber for Scutcheon RH-G3 is a two-component platinum-catalyzed addition-cure elastomer supplied for liquid injection molding of decorative escutcheon plates, emblem surrounds, nameplate gaskets, and integrated trim components. The RH-G3 designation appears as the material callout on part drawings, mold-flow records, and incoming batch documentation. The uncured A and B components are metered in a 1:1 volumetric ratio through a static mixer; no solvent extraction or water-wash stage is used before injection. Cure proceeds by hydrosilylation between vinyl-functional polydimethylsiloxane and methylhydrogensiloxane crosslinker, initiated by a platinum complex at elevated mold temperature. This cure route is distinct from peroxide-catalyzed high-consistency rubber because the gum phase is absent and the compounded liquid can be processed on closed-loop liquid injection molding equipment rather than on a two-roll mill or compression press. Published independent data for the exact RH-G3 formulation are limited; where supplier-published material data are unavailable, the numerical ranges in this document refer to platinum-catalyzed LSR grades evaluated under the cited ASTM and ISO methods and must be confirmed against the RH-G3 certificate of analysis.
Specifications for RH-G3 are normally expressed as a set of cured mechanical values and uncured processing variables rather than a single generic hardness class. Hardness for escutcheon-grade LSR commonly falls between 40 Shore A and 70 Shore A when measured to ASTM D2240-15 on a 6 mm thick specimen with a 15 s dwell. Tensile strength reported under ASTM D412-16 is typically within 4 MPa to 11 MPa for general addition-cure LSR, with elongation at break between 200% and 900%; these values are formulation-dependent and are not RH-G3 limits unless stated on the batch certificate. Tear resistance measured by ASTM D624-00(2020) die C often ranges from 15 kN/m to 50 kN/m. Compression set following ISO 815-1:2019 after 22 h at 175 °C is commonly below 35% for post-cured LSR; automotive escutcheon grades may specify a lower upper bound near 20% to maintain seal-lip contact after thermal aging. Uncured mixed A/B viscosity is normally bracket-tested at 25 °C using ISO 3219; the acceptable range is set by the supplier to match the metering pump and static mixer design rather than by a universal LSR value. Mixed viscosity at 25 °C can vary from 50,000 mPa·s to 500,000 mPa·s across LSR grades, and RH-G3 lot-specific values should be selected with the static mixer element count and injection pressure in mind.
Density measured to ISO 1183-1:2019 is typically in the range of 1.05 g/cm³ to 1.20 g/cm³ depending on filler and pigment loading. Because LSR is shear-thinning, viscosity is reported at a defined shear rate, often 1 s⁻¹ or 10 s⁻¹. Off-ratio mixing outside ±2% shifts the final vinyl-to-hydride stoichiometry and can change Shore A, elongation at break, and compression set. The mixed material has a working life at room temperature that is commonly above 24 h, but the supplier-controlled inhibitor package determines the actual pot life; the working life is not equivalent to shelf life.
On production-scale liquid injection molding cells, RH-G3 is transferred from sealed pails via follower plates into a closed metering unit. The A and B components are kept at 15 °C to 30 °C in the barrel and feed lines; higher line temperature reduces pressure drop but shortens the working life of the mixed material before injection. Mold temperature is set between 150 °C and 200 °C, with thin-wall escutcheon cavities typically using the upper half of this range to reduce cure time. Clamp force is calculated from projected part area and cavity count; multi-cavity tools with 8 to 16 cavities and cold-runner blocks are frequently mounted on presses of 50 t to 150 t, but the final clamp requirement is determined by melt pressure, runner area, and insert area. Injection velocity is selected so that the cavity fills before the gate freezes or the runner heats above the scorch threshold. In sections below 1.0 mm, filling speed is raised to avoid premature gelation at the flow front; in sections above 3.0 mm, velocity is reduced to control air venting and prevent jetting. Cure time for thin-wall LSR parts is commonly 15 s to 60 s for part thickness below 2.0 mm; thicker bosses and insert overmolding require longer hold time depending on mold temperature and platinum level. After demolding, post-cure at 200 °C for 4 h is frequently used to complete the addition reaction, reduce volatile siloxane concentration, and stabilize compression set; for RH-G3, the supplier post-cure cycle must be used rather than a generic schedule.
The static mixer should contain at least 12 to 24 elements for adequate striation mixing of A and B; under-mixed material can exhibit alternating Shore A regions across the molded part. Pressure drop across the static mixer is often 1 MPa to 5 MPa at room temperature depending on mixer length and flow rate. Closed-loop metering systems with positive-displacement pistons can hold shot-weight variation below ±0.5% for LSR; higher variation indicates static mixer bypass, worn check valve, or air entrainment in the feed pail.
The differentiation is not visible from Shore A hardness alone. General-purpose LSR formulations are often optimized for food-contact or medical device molding and may not contain the stabilizer package required for automotive trim. In escutcheon applications, the cured part must retain surface appearance after xenon-arc weathering, steam-jet cleaning, and intermittent contact with automotive chemicals. RH-G3 is positioned in the trim-grade class where volatile siloxane content is reduced by post-cure and stabilizer selection. Volatile organic compound and fogging testing under VDA 278:2011 is used to quantify the residual volatile fraction; generic LSR materials can report total VOC values from 50 µg/g to 800 µg/g depending on post-cure, while automotive interior specifications require confirmation against the specific OEM limit. Fogging condensate is measured as mass per gram or as reflectance reduction on glass plates; no universal LSR value applies because the limit is set by the OEM specification. Exterior escutcheon materials are also tested by xenon-arc exposure under SAE J2527:2021 or ISO 4892-2:2021. The cured silicone backbone is inherently oxidation-resistant, but pigments and gloss surfaces can shift in Delta E after 1,000 h to 3,000 h exposure; a trim-grade compound must satisfy the OEM acceptance limit for color change and gloss retention.
Another difference is tear resistance at the thin seal lip. ASTM D624-00(2020) die C values above 30 kN/m are often specified for demolding and for resistance to installation damage. General-purpose LSR may fall below this value while still meeting tensile and compression-set requirements. Compared with high-consistency rubber, RH-G3 is processed as a liquid and does not require compression or transfer molding; this permits shorter cycle times and integrated encapsulation of rigid thermoplastic carriers. Compared with many thermoplastic elastomer trim materials, LSR retains mechanical integrity after extended exposure to 150 °C to 200 °C, while many TPE/TPV materials are not specified for continuous use above 120 °C. The trade-off is lower resistance to hot hydrocarbon oils; ASTM D471-16a volume swell in IRM 903 oil is higher for silicone than for oil-resistant nitrile or acrylic elastomers.
Adhesion to polycarbonate, PA6-GF, or PC/ABS carriers is not intrinsic. A primer or surface treatment is normally required; adhesion is verified by a 180° peel test to ASTM D6862-11 or by lap shear to ISO 4587:2003 after aging. The exact primer for RH-G3 is identified in the lot documentation and should not be substituted without adhesion validation.
Material compliance for automotive trim LSR is assessed through the OEM material specification and the regulatory requirements of the target market. Because RH-G3 is a silicone elastomer, the supplier may declare compliance with REACH regulation EC 1907/2006 and the EU RoHS directive 2011/65/EU for restricted substances. If the escutcheon is used in a food-contact or cosmetic-contact application, FDA 21 CFR 177.2600 may apply to the cured rubber article, but this does not automatically cover every pigment or additive lot. The following matrix lists test methods commonly referenced on LSR batch certificates; RH-G3 lot-specific applicability is stated in the certificate of analysis.
| Standard or regulation | Designation | Measured property or scope |
|---|---|---|
| ASTM D2240-15 | Durometer hardness | Shore A instantaneous hardness |
| ASTM D412-16 | Tensile properties | Tensile strength, elongation at break, modulus |
| ASTM D624-00(2020) | Tear resistance | Die C tear strength |
| ISO 815-1:2019 | Compression set | Constant deflection at elevated temperature |
| ISO 34-1:2022 | Tear resistance | Trouser, angle, or crescent tear |
| ISO 1183-1:2019 | Density | Specific gravity by immersion |
| ISO 3219 | Rheology | Mixed A/B viscosity at defined shear rate |
| VDA 278:2011 | Volatile emissions | VOC and fogging behavior |
| SAE J2527:2021 | Accelerated weathering | Xenon-arc exposure for exterior trim |
| FDA 21 CFR 177.2600 | Food-contact rubber | Cured articles for repeated food contact, if applicable |
| EU RoHS Directive 2011/65/EU | Restricted substances | Lead, mercury, cadmium, hexavalent chromium, PBB, PBDE |
| REACH EC 1907/2006 | SVHC reporting | Substances of very high concern in formulated lot |
Operational boundaries are equally relevant to batch acceptance. The mixed A/B material is inhibited by sulfur-containing compounds, amine-based mold releases, organotin compounds, and some condensation-cure silicone residues. These substances can poison the platinum catalyst and produce a tacky, undercured part. Mold surfaces and insert carriers must be free of such materials. Storage of sealed pails should be below 30 °C; exposure of opened containers to high relative humidity above 60% can introduce condensed water into the metering unit, creating intermittent soft spots and porosity in thick sections. If cold material is moved into a warm molding room, pails should be allowed to equilibrate before opening to reduce surface condensation. The material should not be blended with peroxide-cure high-consistency rubber or with acetylene-containing additives because the cure systems are not compatible.
At mold temperatures above 190 °C, the cure rate of a platinum-catalyzed LSR increases sharply, but the operating window at the runner and gate narrows. Cold-runner systems are configured to maintain the mixed material below 40 °C; if the runner temperature surpasses 50 °C, the viscosity rise can generate non-fill in thin ribs and produce high injection pressure. The processing boundary is not a single time value because it depends on platinum concentration, inhibitor package, and shear-heating history in the static mixer and sprue. Molding trials for LSR escutcheon plates indicate that a cavity filling time below 5 s is frequently required for wall thickness below 0.8 mm. When the fill time is longer than 10 s, scorch at the gate may appear as flow marks or visible knit lines. Vacuum venting of the parting line at 0.02 mm to 0.05 mm is used to remove air without permitting flash; vent depths above 0.05 mm produce flash on a low-viscosity LSR even at moderate clamp pressure. Shot-to-shot cavity pressure monitoring is used to detect feeding defects; cavity pressure variation above ±5% at peak should trigger inspection of the static mixer, check ring, and cold-runner temperature sensor.
In practice, RH-G3 is specified where the escutcheon must combine a decorative surface with a flexible gasket lip and must survive repeated thermal cycling from -40 °C to 85 °C. The cured silicone remains flexible below -40 °C because the glass transition of the polydimethylsiloxane network is below -100 °C when measured by differential scanning calorimetry to ISO 11357-2:2020. Low-temperature flexibility is therefore not the primary concern; the more common failure modes are insert adhesion loss, gate blush, and surface contamination. Inserts should be demolded from their previous operation and preheated to 80 °C to 120 °C before insertion to minimize condensation and improve mechanical anchoring. If the rigid carrier is PA6-GF, moisture content above 0.2% can create steam porosity at the interface; the insert should be dried to the supplier’s moisture specification before overmolding. Shrinkage compensation of 2.0% to 3.0% linear is typically incorporated into the mold design for LSR escutcheon parts; the exact value depends on filler loading, mold temperature, and post-cure time. Dimensional checks after conditioning at 23 °C and 50% relative humidity for 24 h are used to separate reversible thermal expansion from permanent mold-filling error.
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