| HS Code | 843251 |
| Product Name | Methyl Terminated Hydrogen Branched Silicone Oil RH-H802 |
| Chemical Composition | Methyl-terminated polymethylhydrosiloxane with branched Si-H groups |
| Appearance | Colorless to light yellow transparent liquid |
| Odor | Slight characteristic odor |
| Terminal Group | Methyl |
| Branch Structure | Hydrogen-branched siloxane |
| Viscosity At 25c | 100-500 mPa·s |
| Hydrogen Content | 0.10-0.30 wt% |
| Density At 25c | 0.95-1.05 g/cm³ |
| Refractive Index At 25c | 1.40-1.42 |
| Flash Point | ≥100 °C |
| Volatile Matter | ≤2 wt% |
| Surface Tension | 20-25 mN/m |
| Solubility In Water | Insoluble |
| Solubility In Organic Solvents | Soluble in common organic solvents |
As an accredited Methyl Terminated Hydrogen Branched Silicone Oil RH-H802 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Methyl Terminated Hydrogen Branched Silicone Oil RH-H802 is supplied in 25 kg sealed, lined steel drums for safe storage and transport. |
| Container Loading (20′ FCL) | Loaded in a 20-foot FCL container, Methyl Terminated Hydrogen Branched Silicone Oil RH-H802 is packed securely for safe ocean transportation. |
| Shipping | Methyl Terminated Hydrogen Branched Silicone Oil RH-H802 is shipped in sealed steel drums or IBCs under dry, ventilated conditions, protected from moisture, heat, and sunlight. Follow the SDS and local/international transport regulations; classify per carrier requirements and avoid contact with oxidizers or incompatible materials. |
| Storage | Store in a cool, dry, well-ventilated place away from direct sunlight, heat, sparks, and flames. Keep containers tightly closed and protect from moisture and humid air, as hydride-functional silicone oils may release hydrogen. Separate from oxidizing agents, acids, and bases. Use grounded, labeled containers; avoid prolonged storage above recommended temperatures and follow the SDS. Store under inert gas if specified by the supplier. |
| Shelf Life | Typically 12 months from date of manufacture when stored unopened in a cool, dry place away from direct sunlight. |
For platinum-catalyzed addition-cure liquid silicone rubber (LSR) processed on 25–35 mm reciprocating-screw injection machines with 100–300 t clamp force, RH-H802 is introduced as the Si-H crosslinker in the B component of a 1:1 meter-mix system. The branched methyl hydrogen silicone structure increases the molar concentration of hydrosilylation sites relative to a linear poly(methylhydrogen siloxane) of equal viscosity, which alters network formation in two ways: it shortens the gel point at low addition levels and creates a denser crosslink domain at high addition levels. Compounding practice uses an Si-H:Si-Vi molar ratio of 1.2:1 to 2.5:1; the lower limit is retained for parts requiring elongation at break above 300%, while the upper limit is used only when Shore A hardness above 70 and compression set below 15% after 22 h at 175 °C are critical. At ratios below 1.0:1, under-cure is observed on cured parts as sticky surfaces and compression set rises above 35%; above 2.8:1, residual unbound Si-H migrates to the part surface, producing a tacky exudate that interferes with downstream pad printing and increases mold fouling frequency to every 4–8 h rather than every 24–48 h. Production lines maintain barrel temperature between 18–30 °C to prevent viscosity stratification in the static mixer, which otherwise manifests as shot-weight variability greater than ±1.5%. Cure is carried out at mold temperatures of 150–200 °C with in-mold residence times of 30–120 s, followed by post-cure at 200 °C for 2–4 h for medical-grade parts. Compliance for food-contact and medical LSR includes FDA 21 CFR 177.2600, ISO 10993-5 and ISO 10993-10 for cytotoxicity and skin sensitization, USP Class VI for implantation-relevant extraction, and EU 1935/2004 for food-contact migration. Terminal part types include automotive ignition connector seals, medical duckbill valves, septum seals, dosing pump diaphragms, and infant feeding components.
| Si-H:Si-Vi molar ratio | Shore A hardness | Elongation at break (%) | Compression set after 22 h at 175 °C (%) |
|---|---|---|---|
| 1.0:1 | 35–40 | 400–500 | 35–45 |
| 1.5:1 | 50–55 | 300–400 | 15–20 |
| 2.0:1 | 60–65 | 200–300 | 8–12 |
| 2.5:1 | 70–75 | 100–180 | 5–10 |
In halogen-free low-smoke zero-halogen (LSZH) cable sheath compounding, magnesium dihydroxide and aluminium trihydroxide are pre-treated with RH-H802 in a 500–1000 L Henschel mixer at 120–150 °C for 10–20 min, before the filler is transferred to the main feed or side feeder of a co-rotating twin-screw extruder with an L/D ratio of 44:1. The active silicone dosage is 0.5–1.5 wt% based on filler mass; at 0.8 wt%, moisture absorption of aluminium trihydroxide after 7 d at 85 °C/85% RH is typically reduced from above 1.0% to below 0.3%, and the dispersive torque in the compounder falls by 15–25%. Dosages below 0.3 wt% leave sufficient surface hydroxyl groups to cause melt viscosity instability during extrusion, while dosages above 2.0 wt% generate hydrogen gas and create micro-porosity visible as voids in the sheath cross-section. The treated filler is compounded with an EVA or PE/EVA carrier resin at barrel zone temperatures of 150–180 °C and screw speeds of 250–400 rpm; the resulting compound is granulated and extruded onto copper conductors as LSZH insulation or sheath. Compliance is evaluated against IEC 60754-1 for combustion gas pH and conductivity, IEC 60754-2 for halogen acid gas content, EN 50267-2-1 for acidity, EN 50268-2 for smoke density, and RoHS Directive 2011/65/EU for restricted substances. Terminal product types include building wire sheathing, control cable jackets, railway rolling-stock cables specified to EN 45545-2, and fibre-optic indoor distribution cable jackets.
During platinum-catalyzed hydrosilylation of allyl polyether onto RH-H802 in a 2,000 L glass-lined reactor, the branched methyl hydrogen silicone fluid is charged with an allyl polyether at an allyl ether to Si-H molar ratio of 1.05:1 to 1.20:1. The Pt catalyst concentration is maintained at 2–10 ppm as metal; below 2 ppm, the reaction fails to initiate within 30 min, while above 10 ppm, the rate of allyl-to-propenyl internal isomerization increases and produces non-grafting propenyl polyether that remains as free polyether in the final surfactant. The batch is heated under nitrogen to 100–130 °C and held for 3–8 h; the reaction exotherm is controlled within ±3 °C by internal coil cooling because the hydrosilylation enthalpy is sufficient to overshoot the upper limit and gel the batch if the catalyst is added too rapidly. Conversion is tracked by FTIR disappearance of the Si-H absorbance at 2155 cm⁻¹ and by iodometric active-hydrogen titration to a residual Si-H level below 0.05 mmol/g. The resulting polyether-modified branched silicone is neutralized with sodium bicarbonate, filtered, and then used as a polyurethane foam additive at 0.5–1.5 pphp in flexible slabstock, molded automotive seat foam, and rigid appliance insulation. Compliance requirements for the surfactant and its downstream foams include REACH Regulation (EC) No 1907/2006, ISO 3386-1 for flexible foam compression stress, and FMVSS 302 or ISO 3795:1989 for horizontal burn rate in automotive interior materials.
Dilution of RH-H802 to 5–10 wt% active silicone in isoparaffinic solvent or a water-based emulsion provides a coating that is airless-sprayed onto preheated tire curing bladders at 150–200 °C. The wet film thickness is controlled to 10–20 µm; thicker layers crack under bladder flexure and transfer to the tire inner liner, while thinner layers lose release performance before 100 cycles. After spraying, the film is baked for 10–15 min during which Si-H groups undergo oxidative crosslinking and condensation with residual silanol groups on the mold surface. Reapplication is scheduled after 200–300 press cycles, when peel release force measured on a 25 mm wide tensile strip exceeds 0.5 N/mm or when the bladder surface shows visible brown discoloration. The tire curing press typically operates with bladder inflation pressure of 1.8–2.4 MPa and steam/nitrogen temperature of 170–210 °C; the coating must remain adhered under repeated bladder expansion of 60–80% biaxial strain. Compliance for industrial release applications is covered by REACH Regulation (EC) No 1907/2006 and RoHS Directive 2011/65/EU; if the treated mold is used in incidental food-contact rubber manufacturing, FDA 21 CFR 175.300 applies to the release film. Terminal product types include passenger car radial tires, truck and bus radial tires, bicycle inner-tube curing bladders, and EVA sole mold release films. Limitations: the coating darkens above 200 °C and should not be combined with amine-based accelerators because residual Si-H groups react with amine functionality to form gel particles on the mold surface.
Fumed silica with a BET surface area of 150–400 m²/g is hydrophobized with RH-H802 in a fluidized-bed reactor or a 500–1,000 L high-shear mixer; the Si-H groups condense with silanol groups on the silica surface, releasing hydrogen, and the reaction is run at 120–180 °C for 30–120 min under nitrogen. The silicone dosage is 1–5 wt% based on silica mass; lower dosages are used for high-surface-area grades to avoid residual hydrogen retention, and higher dosages are reserved for densified silica that must disperse without reagglomeration in RTV silicone sealants. After treatment, the hydrophobic silica is deagglomerated in a classifier mill and then compounded into oxime-cure or tin-catalyzed RTV sealants at 5–10 wt% in a 2,000 L planetary mixer under vacuum of −0.09 MPa. The treated silica increases the sealant’s slump resistance and controls rheology; in industrial defoamers, the same hydrophobic silica is dispersed at 1–3 wt% into polydimethylsiloxane carrier fluids. Compliance for the final silicone sealants is assessed according to ISO 11600:2002 for joint movement capability, ASTM C920-18 for elastomeric joint sealants, and REACH Regulation (EC) No 1907/2006 for monomer and hydrogen-siloxane residual content. Terminal product types include construction facade weatherproofing sealants, glazing sealants, appliance gasketing sealants, and industrial defoamers for pulp and paper processing.
Bath stability in textile applications is governed by emulsifier selection and water hardness; RH-H802 is delivered as a 30–40% nonionic oil-in-water emulsion and diluted to 2–5 g/L active silicone in the pad bath. The fabric is padded at a wet pick-up of 60–80% using a horizontal two-roll padder with nip pressure 0.3–0.5 MPa, then dried and cured on a stenter frame at 150–170 °C for 60–120 s. Below 140 °C, film crosslinking is incomplete and the AATCC 22 spray rating remains below 80 after one home laundering cycle according to ISO 6330:2012; above 180 °C, yellowing of polyamide and cellulose blends is measurable as a CIE whiteness loss greater than 5. Bath pot life is 6–8 h when water hardness exceeds 200 ppm CaCO₃; beyond this period, padder roll build-up increases and the fabric develops uneven wetting rows. Compliance for textile finishes includes Oeko-Tex Standard 100 Annex 4 for restricted substances, AATCC 22 for water repellency spray rating, and ISO 6330:2012 for washing durability. Terminal product types include water-repellent workwear, technical outerwear, automotive interior textiles, and luggage fabrics.
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RH-H802 is a methyl-terminated hydrogen branched silicone oil in which terminal trimethylsilyl groups remove silanol condensation activity from the molecule, while silicon-hydride groups remain distributed across a branched siloxane structure. The product model RH-H802 therefore does not behave as a linear polymethylhydrosiloxane, as a silanol-terminated hydrogen fluid, or as an inert dimethyl silicone oil. The methyl terminal cap is the first operational difference: during sealed drum storage it prevents the chain-growth and viscosity drift associated with hydroxy-terminated fluids exposed to moisture or silanol-active fillers. The branched backbone is the second difference: it permits a higher spatial concentration of Si-H groups without the chain entanglement and high-shear viscosity that would be expected from a linear hydrogen silicone fluid of equal hydride weight fraction.
This fluid is directed primarily toward addition-cure silicone formulations and surface hydrophobization operations. In addition cure, the Si-H group reacts with vinyl-functional polyorganosiloxane in the presence of a platinum catalyst. In surface treatment, Si-H groups react with surface silanol groups or participate in moisture-triggered hydrolysis. Both pathways are exothermic or gas-evolving under different conditions, so batch handling is controlled by closed dispensing and gasometric verification rather than by viscosity measurement alone.
Incoming quality control for RH-H802 is structured around the reactive hydrogen content and the physical constants that affect metering. The following values are representative acceptance windows for the branched hydride fluid class; the certificate of analysis for the specific RH-H802 batch should be consulted for the release limits that apply to a given lot. All measurements are taken after the sample has been equilibrated in a sealed container at 25 °C.
| Parameter | Acceptance window / representative value | Test method |
|---|---|---|
| Appearance | Colourless transparent liquid | Visual at 25 °C |
| Kinematic viscosity at 25 °C | 20–40 mm²/s | ASTM D445 |
| Si-H content | 0.30–0.70 wt% | Gasometric titration after alkaline hydrolysis |
| Volatile matter, 3 h at 150 °C | ≤1.0 wt% | ISO 3251 |
| Refractive index at 25 °C | 1.395–1.405 | ASTM D1218 |
| Specific gravity at 25 °C | 0.960–0.990 | ASTM D4052 |
The parameter that most often gates production release is Si-H content. A drift of ±0.05 wt% in hydride content is sufficient to shift the Si-H:Si-vinyl molar ratio in a 100-kg addition-cure compound. Viscosity alone does not detect this drift because the branched fluid may lose hydride to hydrolysis and remain visually unchanged. Gasometric titration is therefore performed on drum samples drawn from the upper 10 % of the drum after nitrogen blanketing has been broken, because the headspace is the region most affected by moisture ingress during partial drum withdrawal.
Solventless release coating operations combine RH-H802 with a vinyl-functional silicone base polymer and a Karstedt platinum catalyst at a Si-H:Si-vinyl molar ratio of 1.0:1 to 1.6:1. Acetylenic inhibitors such as 2-methyl-3-butyn-2-ol are typically introduced at 10–50 ppm relative to total formulation to hold the bath viscosity below 500 mPa·s for 6–8 h at 25 °C; the actual endpoint is formulation-specific and should be revalidated when the base-polymer vinyl content changes. The coating is applied through a five-roll offset coater or a gravure station to a wet film weight of 1.0–1.2 g/m². Cure is carried out in a forced-air oven with a substrate surface profile from 120 °C to 150 °C. When measured on a Brookfield RV viscometer at 20 rpm and 25 °C, a viscosity doubling after 4–6 h is commonly used as the pot-life endpoint.
The narrow processing window arises from the competition between addition cure and Si-H hydrolysis. If the Si-H:Si-vinyl ratio is below 1.0:1, the cured film can contain extractable vinyl silicone species that migrate to the release surface over time. If the ratio exceeds 1.8:1, residual Si-H can hydrolyze in ambient humidity after cure, generating hydrogen and silanol sites that raise release force and create inconsistent peel. The branched architecture of RH-H802 affects this balance because reactive hydride sites are constrained near branch nodes; this can reduce the mobility of unreacted hydride species after gelation and therefore lowers the extractable hydrogen fraction relative to a linear hydride fluid at the same stoichiometric excess. Differential scanning calorimetry of a catalyzed formulation at 10 °C/min typically shows the addition-cure exotherm onset between 95 °C and 115 °C; a second exotherm or sustained heat flow above 150 °C may indicate moisture-induced side reactions.
Release force is evaluated according to FINAT FTM 3 at 300 mm/min peel speed; target values are set per grade. Under-cured or contaminated films often show an increase in release force after 24 h conditioning at 40 °C, accompanied by higher extractable silicone levels measured by solvent extraction. The extractable fraction is influenced more by available hydride content than by total coated silicone, so RH-H802 lot approval should be based on hydride concentration and the resulting stoichiometric ratio, not on fluid viscosity alone.
In linear methyl hydrogen silicone oil, the Si-H group is predominantly attached to a difunctional D unit. After hydrosilylation, the reacted hydride becomes a pendant group or siloxane bridge that does not add a new siloxane network branch by itself. In a branched hydrogen silicone fluid, a fraction of the hydride groups can be located on T units or adjacent to branch nodes. When such a group reacts, the local network connectivity increases more than in the linear case, because the junction already carries a third siloxane linkage into the branch structure. This structural difference is measurable in the cured network through gel fraction, solvent swelling, and dynamic mechanical analysis. Published data for the exact RH-H802 cured network are limited, but the class behaviour is as follows: at equal Si-H:Si-vinyl ratio, branched hydride fluids tend to produce higher gel fractions and lower linear-species extractables, while also reducing the concentration of free hydride chains that can migrate before cure.
The practical consequence is that RH-H802 can be used at a lower Si-H excess than a linear hydride fluid of the same hydride content. Reducing the Si-H:Si-vinyl ratio from 1.6:1 to 1.2:1 in a release coating formulation may still pass extractables limits because the branched topology places hydride functions in network-forming positions rather than as chain-remote or pendant-only functions. This benefit must be weighed against the higher local Si-H concentration, which lowers the tolerance to moisture and increases hydrogen evolution if uncovered vessels are used.
Compared with silanol-terminated hydrogen fluids, RH-H802 has no terminal silanol condensation pathway. This removes the slow viscosity increase observed in semi-closed coating baths where hydroxy-terminated chains condense at the surface under warm, humid conditions. The methyl terminal cap also lowers chain-end polarity, which improves solubility in aliphatic solvents and reduces water uptake at the liquid-air interface.
In anti-foam compounding, RH-H802 is typically reacted onto fumed or precipitated silica in a ploughshare mixer at 80 °C to 120 °C for 1–3 h. The Si-H groups react with surface silanols, generating hydrogen. The mixer headspace must be continuously vented or inerted because hydrogen-air mixtures are flammable between 4 % and 75 % hydrogen by volume. Batch-to-batch variation in the silica silanol content shifts the amount of hydride consumed during the surface treatment; therefore the Si-H content of the RH-H802 charge is measured before and after the reaction. Silica treatment is usually incomplete until the headspace hydrogen concentration plateaus and the fluid becomes hydrophobic in a wetting test. Published data for this specific configuration is limited, but the sequence of surface hydrophobization and subsequent dispersion into carrier oil is a standard route.
After surface treatment, the product is dispersed into a high-shear mixer at 1,000–3,000 rpm to produce a silicone anti-foam concentrate. At this stage the key process conflict is local temperature; shear heating above 120 °C can trigger further Si-H reaction with residual moisture and form gel particles. Temperature is therefore maintained by jacket cooling, and water additions are avoided until the concentrate is fully dispersed.
For emulsion-based anti-foam production, the product may be emulsified with nonionic surfactants; however, amine-emulsifier packages or alkali-stabilized water phases must be excluded because pH above 7.5 accelerates Si-H hydrolysis and hydrogen generation. The same rule applies to silicone emulsions intended for textile finishing.
RH-H802 must be protected from strong bases and amine-containing additives. Amines raise pH locally and catalyze Si-H hydrolysis and dehydrogenative coupling, leading to hydrogen gas formation and premature gelation. Organotin condensation catalysts can also interfere; dibutyltin dilaurate is not a direct platinum-catalyst poison, but its alkaline degradation products or co-formulated amines can destabilize the hydride fluid. The operational boundary is therefore that RH-H802 and its concentrates should not be compounded with amine-functional silanes, ammonia-based pH adjusters, or tin catalysts unless the full formulation has been tested at 40 °C for 48 h in a sealed vial with headspace monitoring.
In aqueous emulsion applications, pH is maintained below 7.5. Alkaline pH accelerates Si-H hydrolysis and generates hydrogen while consuming the reactive function needed for subsequent cure or hydrophobization. At ambient relative humidity above 60 %, substrates and fillers are pre-dried at 120 °C for 2 h before compounding to reduce hydrolytic Si-H loss. Storage tanks are blanketed with dry nitrogen and fitted with desiccant vent dryers when the product is held in day tanks.
For textile and glass-fiber hydrophobization, RH-H802 is typically diluted to 1–5 wt% silicone solids in an aliphatic or aromatic solvent, applied by pad or spray, and cured at 130–160 °C for 1–3 min. The methyl blocks on the siloxane backbone provide low surface energy after cure, while residual Si-H groups can react with the substrate or crosslink in the presence of a platinum catalyst. This process route uses the branched structure to deposit a higher crosslink-density film than would be obtained from a linear hydride fluid at the same bath concentration. However, the bath must be protected from moisture: solvent stock containing more than 500 ppm water can consume hydride during storage and reduce the cure after application. For metal surfaces, the same cure window applies after solvent flash-off, and the coated surface is inspected for water contact angle, typically 95–110°, measured by sessile drop goniometry under ASTM D7334 after cooling. If contact angles fall below 90°, the cause is usually hydrolysis of Si-H in the bath rather than cure temperature.
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