| HS Code | 923912 |
| Product Name | Silicone Gel RH-PG-589H |
| Product Type | Two-component addition-cure silicone gel |
| Appearance | Colorless transparent liquid |
| Mixing Ratio | A:B = 1:1 by weight |
| Viscosity 25c | Typical 1000–2000 mPa·s |
| Density 25c | Typical 0.98–1.05 g/cm³ |
| Hardness | Typical Shore 00 30 |
| Penetration | Typical 200–300 (1/10 mm) |
| Tensile Strength | Typical ≥1.0 MPa |
| Elongation At Break | Typical ≥100% |
| Tear Strength | Typical ≥5 kN/m |
| Linear Shrinkage | Typical ≤0.1% |
| Thermal Conductivity | Typical 0.2 W/m·K |
| Dielectric Strength | Typical ≥20 kV/mm |
| Volume Resistivity | Typical ≥1×10^14 Ω·cm |
| Dielectric Constant | Typical 2.8–3.0 at 1 MHz |
| Dissipation Factor | Typical ≤0.001 at 1 MHz |
| Operating Temperature | Typical -50°C to 200°C |
| Curing Condition | Typical 25°C/24 h or 80°C/1 h |
| Pot Life 25c | Typical 2–4 h |
As an accredited Silicone Gel RH-PG-589H factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Silicone Gel RH-PG-589H is packaged in 20 kg sealed plastic pails with tamper-evident lids and clear hazard labels. |
| Container Loading (20′ FCL) | Silicone Gel RH-PG-589H is palletized and securely loaded into a 20′ FCL container with bracing and moisture protection for safe transport. |
| Shipping | Silicone Gel RH-PG-589H is typically shipped as a non-hazardous, non-flammable silicone product in sealed, labeled containers. Protect from moisture, direct sunlight, and extreme temperatures; transport in clean, dry vehicles. Follow the SDS and verify carrier/regulatory requirements before shipment; inspect containers for leaks or damage. |
| Storage | Store Silicone Gel RH-PG-589H in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, and flames. Keep containers tightly closed and properly labeled. Protect from moisture, dust, and contamination. Avoid contact with incompatible chemicals and store separately from oxidizers. Maintain stable temperature, prevent freezing if specified by supplier, and follow SDS/local regulations. Ensure spill containment and adequate ventilation. |
| Shelf Life | Silicone Gel RH-PG-589H typically has a six-month shelf life when stored unopened in a cool, dry place away from sunlight. |
IEC 60664-1:2020 clearance and creepage verification under pollution degree 2, combined with UL 94 V-0 flame classification at 3.0 mm thickness, defines the acceptance envelope for RH-PG-589H in IGBT and SiC MOSFET power module cavities. The addition ratio is fixed at 1:1 by weight on a gravimetric dispense loop, with A-component deviation limited to ±0.5 wt% per shot. Production-scale potting uses a vacuum-metering system fitted with a 24-element static mixer and chamber pressure of 10–50 mbar; the mixed gel is introduced at 23±2 °C and cured in an air-circulation oven at 80 °C for 30 min, followed by a post-cure at 120 °C for 1 h to reduce extractable cyclic siloxanes. The main process bottleneck is not degassing but localized cure inhibition on substrates retaining amine-bearing solder mask residues or sulfur-containing liner residues; batch-to-batch hardness shift on production lines typically appears as Shore 0000 values falling from 55–65 to below 45 when the A:B ratio drifts below 0.98:1. Finished product types include traction motor inverter modules, auxiliary DC-DC converter bricks, and high-current power distribution assemblies.
Photovoltaic junction boxes with bypass diodes require potting gels that remain non-corrosive to pre-tinned copper tabs under 85 °C/85% RH damp heat conditions, with the governing documents being IEC 62790:2020 for junction box safety and IEC 61215-2:2021 for module-level thermal cycling and humidity freeze. RH-PG-589H is fed at 1:1 by weight through a 2K pneumatic metering machine; the production line typically uses a dispense pressure of 0.2–0.4 MPa with a needle inner diameter of 0.84 mm and robotic fill volume tolerance ±0.1 mL. Cure is set at 105 °C for 12 min in a convection oven, followed by 150 °C for 1 h to suppress outgassing. The dominant failure mode at the junction-box level is insufficient wetting of PPO/PA housing walls, producing lateral flash and diode wire-bond abrasion during thermal cycling from −40 °C to 85 °C. Terminal products include photovoltaic combiner junction boxes, module-level power electronics, and microinverter cavity-fill assemblies.
For medical cushioning converted from RH-PG-589H, the governing requirement is not bulk hardness but a sequential biological file including ISO 10993-5:2009 cytotoxicity with MTT reduction not less than 70% of blank, ISO 10993-10:2021 skin sensitization absence, ISO 10993-23:2021 irritation potential, and USP Class VI 87/88 systemic injection and implantation data. The production ratio is held at 1:1 by weight, but medical-grade batches add an inline FTIR check for Si–H peak decay at 2,160 cm−1 before casting because residual Si–H sites can alter the aqueous extractables profile after protein contact. Downstream conversion typically casts the degassed mixture into thermoformed polyurethane film cavities at thicknesses from 0.5 mm to 3.0 mm, vacuum-degases at −0.095 MPa for 8–12 min, and cures at 80 °C for 20 min, followed by a post-cure at 120 °C for 2 h to depress D4/D5 cyclic siloxane outgassing. A measurable conversion risk is pot-life drift when the mixed material exceeds 30 min at 25 °C; delayed casting lines report edge hardness gradients because network formation begins before final thickness is defined. Terminal products include scar therapy sheeting, respiratory mask cushions, and orthotic interface pads.
Chip-on-board LED arrays with rigid epoxy dome encapsulation experience wire-bond shear stress across thermal cycles; RH-PG-589H can function as a low-stress encapsulant, but published optical transmittance and yellowness index data for this specific configuration is limited; qualification must be performed on the actual COB architecture using IEC 62031:2018 LED module safety and ANSI/UL 8750:2015 equipment-level dielectric requirements. The A:B ratio is maintained at 1:1 by weight, and the material is dispensed into the aluminum reflector cavity at a controlled height from 0.3 mm to 0.8 mm above the phosphor layer; cure schedule is 100 °C for 15 min, followed by 150 °C for 2 h under nitrogen. The critical production constraint is moisture contamination: A-component storage above 60% relative humidity can generate silanol-related haze at the cavity surface after thermal aging, reducing luminous flux maintenance below LM-80 thresholds. Terminal products include horticultural lighting engines, automotive interior light pipes, and high-density COB downlights.
Because under-bonnet thermal cycling does not test bulk hardness as the primary acceptance criterion, the governing evidence is modulus retention and surface cure under chemical loading, documented against ISO 16750-5:2023 for chemical loads, ISO 16750-4:2023 for climatic cycling, and SAE J1455 for heavy-duty vehicle electronic system performance. RH-PG-589H is metered at 1:1 by weight through a servo-driven 2K dispenser with shot size accuracy ±0.05 g at fill temperature 25±2 °C, then deaerated under 5–20 mbar chamber vacuum and cured at 85 °C for 30 min, followed by post-cure at 125 °C for 2 h to complete hydrosilylation. A known process boundary is exposure to sulfur-containing sealing compounds or amine-cured gaskets; residual sulfur levels as low as 10 ppm at the housing interface can inhibit surface cure and leave a tacky gel layer, requiring segregation of sulfur-crosslinked rubber parts from the potting cell. Terminal products include diesel engine camshaft position sensors, transmission oil pressure sensors, and wheel speed sensor interfaces.
| Application scenario | Primary standard | Secondary standard | Test endpoint / production note |
|---|---|---|---|
| Power module cavity potting | IEC 60664-1:2020 | UL 94 V-0, 3.0 mm | Pollution degree 2 clearance/creepage, vertical burn classification |
| Photovoltaic junction box | IEC 62790:2020 | IEC 61215-2:2021 | Damp heat 85 °C/85% RH, thermal cycling |
| Medical cushioning | ISO 10993-5:2009 | ISO 10993-10:2021, USP 87/88 | MTT reduction ≥ 70%, sensitization absence |
| COB LED encapsulant | IEC 62031:2018 | ANSI/UL 8750:2015 | Dielectric safety, thermal aging, LM-80 flux maintenance |
| Under-bonnet sensor potting | ISO 16750-5:2023 | ISO 16750-4:2023, SAE J1455 | Chemical load resistance, climatic cycling |
| Application scenario | A:B addition ratio | Cure profile | Post-cure | Equipment / critical limit |
|---|---|---|---|---|
| Power module cavity potting | 1:1, ±0.5 wt% | 80 °C 30 min | 120 °C 1 h | Vacuum 10–50 mbar, 24-element static mixer |
| Photovoltaic junction box | 1:1 | 105 °C 12 min | 150 °C 1 h | Dispense 0.2–0.4 MPa, needle ID 0.84 mm |
| Medical cushioning | 1:1 | 80 °C 20 min | 120 °C 2 h | Vacuum −0.095 MPa, pot life 30 min |
| COB LED encapsulant | 1:1 | 100 °C 15 min | 150 °C 2 h | Nitrogen cure, storage RH below 60% |
| Under-bonnet sensor potting | 1:1 | 85 °C 30 min | 125 °C 2 h | Vacuum 5–20 mbar, shot ±0.05 g |
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Two-part addition-cure Silicone Gel RH-PG-589H is formulated for void-free encapsulation of low-voltage power electronics, automotive sensor assemblies, and LED drive modules. The mixed system cures to a soft, optically translucent elastomer with a Shore 00 hardness usually between 55 and 75 after 30 min at 100 °C; post-cure 2 h at 120 °C stabilizes the platinum-catalysed crosslink network and lowers residual volatile siloxane content. Uncured mixed viscosity at 25 °C is 700–1,200 mPa·s under ISO 3219, which permits low-pressure dispensing through needle diameters of 0.25 mm at shot pressures below 4 bar. The cured gel remains tack-free on its surface but retains adhesive wetting to aluminium, FR-4, ceramic substrates, and passivated copper. Unlike condensation-cure silicone gels, RH-PG-589H does not evolve methanol, acetic acid, or oxime by-products during vulcanization; no additional ventilation is required for small sealed modules, provided the cure schedule is followed and the mixed material is not contaminated by organotin or amine residues. Continuous operating temperature is rated from −50 °C to 180 °C. At 200 °C intermittent exposure, hardness may increase by 10–15 Shore 00 points within 500 h because of oxidative crosslink densification, so continuous use above 180 °C should be validated under end-product thermal cycling.
| Property | Method | Value |
|---|---|---|
| Mixed viscosity, 25 °C | ISO 3219 | 700–1,200 mPa·s |
| Shore 00 hardness after cure | ASTM D2240 | 55–75 |
| Penetration, 25 °C | ISO 2137 | 12.0–18.0 mm |
| Density, cured | ISO 1183-1 | 0.97 g/cm³ |
| Dielectric strength, 2 mm sheet | IEC 60243-1 | 16–20 kV/mm |
| Volume resistivity, 500 V | IEC 62631-3-1 | 1.0×1014 Ω·cm |
| Thermal conductivity | ISO 22007-2 | 0.18–0.22 W/m·K |
| Cure schedule, minimum | isothermal DSC | 20 min at 100 °C or 10 min at 120 °C |
The principal operational difference is cure chemistry. Condensation-cure gels rely on moisture-triggered alkoxy, acetoxy, or oxime hydrolysis and release low-molecular-weight by-products that can attack copper traces, silver-coated bond pads, and sensitive optical surfaces in closed cavities. RH-PG-589H uses a Pt-catalysed hydrosilylation reaction between vinyl-functional siloxane and Si—H crosslinker; conversion is stoichiometric and no volatile cleavage product separates from the network. This difference matters for zero-vent modules because encapsulated reed switches, micro-electromechanical-system relays, and photodiodes remain free of fugitive organic ions. Shrinkage during cure is also lower: typical addition-cure gels show linear shrinkage below 0.1%, while condensation systems commonly shrink 0.5–1.5% and may pull away from connector walls. However, addition-cure gels are sensitive to platinum catalyst poisoning by sulfur-cured elastomers, amines, phosphines, and some tin compounds. For RH-PG-589H, contact with RTV-1 acetoxy sealants, black EPDM gaskets, or amine-containing conformal coatings must be excluded from the application area.
Compared with phenyl-functional optical gels, RH-PG-589H has a lower refractive index, typically 1.41 at 589 nm, and is not intended for primary LED optics where refractive index matching to sapphire or silicone encapsulates above 1.50 is required. It is instead formulated as a low-modulus mechanical buffer and dielectric barrier. The absence of phenyl groups improves aliphatic oxidation resistance at moderate service temperatures but reduces UV stability; long-term direct sunlight exposure can embrittle the surface and is not recommended without an opaque housing. Relative to aromatic polyurethane gels, RH-PG-589H offers a wider service temperature range and lower hydrolytic degradation; many polyurethane gels soften near 120 °C and can hydrolyze in sealed humid enclosures within 500 h at 85% RH. Relative to rigid epoxy encapsulants, the silicone gel exerts orders-of-magnitude lower thermomechanical stress on solder joints because of modulus differences; epoxy Shore D 70–85 contrasts with silicone Shore 00 55–75. However, epoxy provides better solvent resistance and mechanical cut-through resistance.
Production trials on LED driver potting lines have shown that the practical dispense window is set less by gelation than by filler settling and gas entrainment. Meter-mix equipment using a 24-element static mixer with an L/D of 18:1 delivers homogeneous material at 2–5 mL/s continuous flow; below 2 mL/s, transient pressure fluctuations across the mixer can create air ingression at needle tips. Above 5 mL/s, adiabatic shear heating raises mixed temperature by 3–5 °C, shortening pot life moderately. A two-stage disposable static mixer with 32 elements reduces striation thickness but increases backpressure from 0.8 MPa to 1.5 MPa at 25 °C. For high-volume potting of cavities deeper than 10 mm, vacuum assistance at 1–5 kPa for 3–5 min is recommended after dispense. Air bubbles trapped beneath adjacent wire bonds can expand during solder reflow or thermal cycling, generating partial discharge sites and local dielectric failure.
At 25 °C, the mixed viscosity doubles in approximately 4 h; at 40 °C, the doubling time falls to 45–60 min. This imposes a batch-life limit on slow dispensing lines: the same material cannot be held overnight and re-used without risk of partial crosslinking and non-uniform wetting. Differential scanning calorimetry shows an isothermal peak exotherm near 100 °C with conversion exceeding 95% after 30 min; residual heat of reaction after 120 °C post-cure is below 5 J/g. Accelerated cure at 150 °C for 5 min is used for thin sections under 3 mm; thicker sections above 10 mm should not be heated faster than 5 °C/min because the exotherm may produce internal voids and modulus gradients. The gel does not require oven humidity control during cure, but condensation of water on uncured surfaces from cold storage should be avoided before mixing. If the product is stored at −20 °C, containers must be sealed and brought to 20–25 °C for 4–6 h before opening to prevent water contamination. Published data for RH-PG-589H is limited to standard cure profiles and lot-release properties; application-specific thermal profiles should be verified on production parts.
At continuous service temperatures between 120 °C and 150 °C, the dominant failure mode in RH-PG-589H is not thermal decomposition but migration of platinum catalyst residues into adjacent polymer seals, where trace unsaturated additives can consume residual hydride. In multi-cavity power modules with PBT connector housings, outgassing from PBT stabilizers above 130 °C can discolor the gel within 500 h; suitability must be tested according to IEC 60068-2-14 thermal shock. Flexible copper leadframes with sharp edges can cut the gel during vibration testing; fillets should be radiused or a higher durometer edge bead applied. The cured gel resists humid aging, but liquid water immersion at 85 °C for 1,000 h increases dielectric constant by approximately 0.1–0.2 and reduces volume resistivity by roughly one decade; module seals should be validated accordingly.
For small-signal analog circuits, ionic impurities in the silicone network can induce drift in drain leakage or photodiode reverse current. RH-PG-589H is specified with extractable chloride below 5 ppm, extractable sodium below 2 ppm, and extractable ammonium below 5 ppm, determined by ion chromatography after reflux extraction according to IPC-TM-650 2.3.28. Dielectric constant at 1 MHz is 2.8–3.0; dissipation factor at 1 MHz is 0.001–0.005. After 1,000 h at 85 °C/85% RH under IEC 60068-2-67, dissipation factor can rise to 0.01 at 1 kHz, but the material remains electrically insulating. For modules containing bare semiconductor die without passivation, a silane-based adhesion promoter compatible with hydrosilylation cure is applied to leadframes before gel dispense; omission can result in interfacial moisture wicking along copper-leadframe interfaces and local electrochemical migration.
| Regulation / standard | Scope | Status |
|---|---|---|
| RoHS Directive 2011/65/EU Annex II | Pb, Hg, Cd, Cr(VI), PBB, PBDE | Pass |
| REACH Regulation (EC) 1907/2006 | SVHC candidate list | No SVHC above 0.1 wt% |
| IEC 62631-2-1 | DC insulation resistance of cured gel | ≥1.0×1012 Ω |
| UL 94 | Flammability, 3 mm specimen | V-0 equivalent, oxygen index 28 |
Automotive power modules combine IGBT or SiC MOSFET dies, aluminium wire bonds, nickel-plated copper bus bars, and a polyphthalamide housing. In this configuration, the gel must absorb coefficient of thermal expansion mismatch between copper at approximately 17 ppm/K and the polymer housing at approximately 30–40 ppm/K across −40 °C to 125 °C thermal cycling. The low elastic modulus of RH-PG-589H, typically 20–60 kPa at 25 °C under ISO 37 split tensile testing, reduces shear stress at wire-bond heel joints relative to rigid epoxies. However, the same low modulus provides little resistance to silicone creep under constant pressure: at 80 °C and 50 kPa compressive load, creep compliance increases and the material may flow away from pressure points over hundreds of hours. In modules with spring-loaded bus bars, this behavior requires mechanical retention because the gel cannot substitute for a positive clamp. Published data for creep recovery of RH-PG-589H in this specific configuration is limited.
Voltage stress at sharp wire-bond tips concentrates electric fields. At 1 kV/mm, the gel remains free from internal partial discharge below inception voltage thresholds determined by void size. Vacuum potting is therefore mandatory for SiC modules operating above 1.2 kV; any void larger than 50 µm near a bond tip may ionize under fast switching transients and erode the gel. In contrast to alumina-filled thermally conductive silicones, RH-PG-589H does not raise thermal conductivity enough for high-loss semiconductor stacks; modules dissipating more than 5 W/cm² require a separate alumina or aluminium nitride thermal interface layer.
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