| HS Code | 906425 |
| Appearance | Colorless transparent liquid |
| Odor | Slight characteristic odor |
| Viscosity At 25c | 50-100 mPa·s |
| Hydrogen Content | 0.10-0.15% |
| Density At 25c | 0.95-0.99 g/cm³ |
| Refractive Index At 25c | 1.400-1.410 |
| Flash Point | ≥100 °C |
| Volatile Matter | ≤2.0% |
| Active Content | ≥99% |
| Ph Value | 6-8 |
| Solubility | Soluble in toluene and xylene; insoluble in water |
| Storage Temperature | 5-30 °C |
As an accredited Dual-end Hydrogen Silicone Oil RH-H59 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dual-end Hydrogen Silicone Oil RH-H59 is supplied in 200 kg sealed steel drums for safe industrial transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL loaded with Dual-end Hydrogen Silicone Oil RH-H59 in sealed drums, palletized, secured, and evenly distributed for sea transport. |
| Shipping | Dual-end Hydrogen Silicone Oil RH-H59 is normally shipped as a non-dangerous industrial chemical in sealed 25 L/200 L drums or IBCs. Store and transport upright in a cool, dry, well-ventilated area, protected from moisture, heat, and direct sunlight. Verify SDS and local transport rules before shipment. |
| Storage | Store Dual-end Hydrogen Silicone Oil RH-H59 in its original, tightly closed container in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, flames, and strong oxidizers. Protect from moisture and contamination. Keep separate from acids, alkalis, and catalysts. Use explosion-proof ventilation where required. Maintain labeled containers, observe local regulations, and do not store near food or feed. |
| Shelf Life | Typically 12 months when stored in a sealed container, dry, and away from heat and moisture. |
Addition-cure liquid silicone rubber (LSR) constitutes the largest-volume downstream route for terminal Si-H functional RH-H59, where it is incorporated as a chain extender rather than as a multifunctional crosslinking node. In two-component injection molding systems, RH-H59 is metered into the vinyl-functional polydimethylsiloxane (Vi-PDMS) stream at 2–8 phr relative to 100 phr Vi-PDMS, with the terminal Si-H/vinyl molar ratio held in the 0.60–1.10 range. The lower limit keeps residual vinyl groups below 0.05 mmol/g after cure, while the upper limit prevents moisture-induced hydrogen microvoid formation in parts with wall thickness above 4 mm. Compliance for food-contact and skin-contact articles is governed by US FDA 21 CFR 177.2600, EU 10/2011, LFGB, and BfR Recommendation XV; cytotoxicity is screened under ISO 10993-5:2009 and sensitization under ISO 10993-10:2010. On a 125–150 metric ton electric injection molding machine with a 24:1 L/D screw and cold-runner block set at 18–25 °C, the mixed compound is injected into molds heated to 160–200 °C. Cure time is 30–75 s at 170 °C. Production lines record injection pressure between 35–70 MPa depending on part geometry and gate diameter; a static mixer with 12–24 elements is used at pressure drop 2–8 MPa. The process is sensitive to inhibitor carry-over from amine-containing mold release agents; styrene-butadiene rubber residues in the barrel above 0.5 % cause premature gelation. Finished goods include rounded-tip pacifier nipples, peristaltic pump tubing, reusable coffee-cup sealing rings, and overmolded gaskets for food storage containers.
In surface-mount device (SMD) LED encapsulants, RH-H59 is combined with phenylvinyl silicone resin to suppress modulus while maintaining a refractive index in the 1.40–1.54 band. The terminal Si-H/vinyl molar ratio is maintained at 0.80–1.50, corresponding to 3–10 wt% RH-H59 in the non-volatile portion; ratios below 0.70 produce tacky surfaces and reduced adhesion to silver-coated leadframes on PCT/EMC substrates. Optical transmission is assessed by ASTM D1003-21 total luminous transmittance, with haze measured according to ASTM D1044-19; thermal aging at 150 °C for 1,000 h under JEDEC JESD22-A103E is used to detect yellowing. In dispensing production, a dual-cartridge pneumatic dispenser with static mixer elements of 24–32 stages is used; vacuum deaeration is applied at 0.5 kPa for 5–10 min before cure. Cure profile is 100 °C for 1 h followed by 150 °C for 3 h. Moisture above 300 ppm in the feed produces bubble defects visible under 40× stereomicroscope. Terminal product types include 2835, 5050 SMD leadframe packages, chip-on-board (COB) encapsulation, and low-warpage via fill for LED modules. Published data for the specific configuration of terminal hydrogen silicone oil at the upper refractive index range with TiO₂-filled dam systems is limited.
Dielectric gel potting for power modules and battery-management circuits uses RH-H59 at 0.5–3 wt% of the total vinyl silicone composition, with Si-H/vinyl molar ratio confined to 0.65–0.95 to avoid residual Si-H that reacts with aluminum substrates under thermal cycling. The cured gel is characterized by penetration in the 3–8 mm/10 cone range under ISO 2137:2017 and dielectric strength tested at ≥15 kV/mm using IEC 60243-1:2013; flammability classification is UL 94 V-0 at 1.5 mm thickness. Production potting is performed under vacuum ≤1 kPa, followed by 60 °C gelation for 30 min and 100 °C post-cure for 1 h in a convection oven with ±2 °C uniformity. Silicone gel with too low terminal Si-H shows uncured zones around copper leadframes; platinum catalyst poisoning from residual solder flux containing amine activators has been observed to increase gelation time from 30 min to over 4 h. Terminal products include insulated-gate bipolar transistor (IGBT) module cavity fill, EV battery pack low-pressure gasketing gel, and sensitive MEMS sensor encapsulation.
| Application scenario | Standard | Scope |
|---|---|---|
| LSR food-contact molding | 21 CFR 177.2600 | Rubber articles for repeated food contact |
| LSR medical skin contact | ISO 10993-5:2009 | In vitro cytotoxicity |
| LSR medical skin contact | ISO 10993-10:2010 | Irritation and skin sensitization |
| LED optical encapsulant | ASTM D1003-21 | Total luminous transmittance |
| LED optical encapsulant aging | JEDEC JESD22-A103E | High temperature storage life |
| Dielectric gel | IEC 60243-1:2013 | Electric strength |
| Dielectric gel flammability | UL 94 V-0 | Vertical burn classification |
| Silicone foam | ASTM D1056-20 | Flexible cellular rubber classification |
| Release coating | 21 CFR 176.170, 21 CFR 176.180 | Components for paper and paperboard in contact with food |
| Textile intermediate | ZDHC MRSL Version 3.1 | Restricted substances in textile processing |
RH-H59 participates in water-blown expansion through terminal Si-H hydrolysis at 40–90 °C, generating hydrogen gas when the compound contains 0.1–0.8 phr deionized water and platinum catalyst at 5–20 ppm Pt based on total compound. The terminal hydrogen oil is added at 1–4 phr to a vinyl silicone gum with vinyl content 0.05–0.25 mmol/g; below 1 phr cell density is insufficient, above 4 phr expansion pressure causes premature froth collapse before the crosslinking network forms. Processing is performed on a twin-screw extruder with L/D 32:1 and segmented barrel temperatures from 35 °C to 95 °C, followed by a hot-air tunnel at 150–180 °C for 8–20 min. Density is controlled between 0.25 g/cm³ and 0.60 g/cm³ under ASTM D1056-20; compression set is tested by ISO 815-1:2019 at 70 °C for 22 h. Flame-retardant versions intended for EV battery pack thermal-runaway barriers are additionally classified by UL 94 V-0 at 3 mm and FMVSS 302. In production, batch-to-batch variance in silanol content of precipitated silica filler above 0.5 % shifts foam density by ±0.08 g/cm³. Terminal products include compressible gap fillers, battery pack fire-barrier foams, and door-seal profiles with closed-cell surface skin.
Solventless thermal release coatings use RH-H59 as a difunctional chain extender to shift release force from a tight 6–12 cN/25 mm range to a moderate 20–45 cN/25 mm range without additional silicone migration to the adhesive. Addition ratio in the coating bath is 4–12 wt% of the vinyl-functional silicone base polymer, with C=C/Si-H molar ratio maintained at 1.0:0.90–1.0:1.10. Coating is applied by five-roll solventless silicone coating head at 0.8–1.5 g/m² onto corona-treated PET or PE liner; web speed runs at 120–300 m/min, with oven zones at 140–180 °C and dwell time 10–30 s. Compliance for direct food contact release liners is evaluated under 21 CFR 176.170 and 21 CFR 176.180; migration limits follow EU 10/2011 with overall migration <10 mg/dm². Residual terminal Si-H above 0.05 mmol/g in the cured film causes post-cure release increase and a mottled silicone surface detected by contact angle hysteresis above 10° using ASTM D7490-13. Terminal products include release liners for high-speed label stock, die-cut release liners for medical pouches, and differential release packaging for process liners.
As a reactive building block, RH-H59 is fed into a 500 L glass-lined reactor at 45–55 wt% of the total batch, where allyl-terminated polyethylene glycol monoethyl ether with Mn 400–1,000 g/mol is added to achieve C=C/Si-H molar ratio 1.02–1.08. Karstedt catalyst at 2–8 ppm Pt is dosed after vacuum azeotropic removal of water to ≤200 ppm; reaction temperature is staged from 85 °C to 110 °C over 2–4 h until Si-H disappearance is confirmed by FTIR at 2,160 cm⁻¹ below detection limit. The resulting ABA block copolymer is neutralized with 0.5 % sodium bicarbonate, vacuum-stripped at 120 °C and 5 kPa, and filtered through a 5 µm bag filter. Industrial hygiene compliance is assessed under REACH and the downstream textile processing standard ZDHC MRSL Version 3.1; residual platinum content is controlled below 10 ppm by ICP-MS. In textile softener formulations, the block copolymer is post-dispersed with a high-shear rotor-stator device at 3,000 rpm and 40 °C for 20 min. Terminal product types include hydrophilic silicone softeners for cotton knit, agrochemical tank-mix adjuvants, and industrial defoamers for dyeing machines. Published data for the specific end-use spreadability performance of RH-H59-derived ABA block copolymers on recycled polyester is limited.
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Dual-end Hydrogen Silicone Oil RH-H59 is an α,ω-dihydrido polydimethylsiloxane with silicon-bonded hydrogen positioned at both terminal siloxane units. This telechelic hydride structure supplies 2 Si–H sites per molecule and therefore functions as a linear chain extender in platinum-catalyzed hydrosilylation rather than as a multi-arm branch former. The product is normally supplied as a clear liquid with viscosity in the 20–100 mPa·s range at 25 °C, active hydrogen content between 0.03 wt% and 0.10 wt%, and density in the 0.955–0.970 g/cm³ range. Industrial use concentrates in addition-cure liquid silicone rubber, silicone gels, electronic potting compounds, and solvent-free coatings where low modulus, high elongation, and controlled crosslink density are required. Unlike side-chain methylhydrogen silicone fluids, RH-H59 yields fewer trifunctional or tetrafunctional crosslinks at equivalent SiH:vinyl stoichiometry, so the cured network typically develops a more linear segmental topology. This shift alters Shore A hardness, elongation at break, and compression set behavior. The product is not a condensation-cure silane and is not interchangeable with tin-catalyzed moisture-cure silicone fluids.
Lot-to-lot control for RH-H59 combines viscometric, hydride, and volatility measurements. Viscosity is determined using a rotational viscometer according to ISO 3219:2021 at 25 °C, while density is measured by the immersion or pycnometer method of ISO 1183-1:2019. Refractive index is reported at 25 °C by ASTM D1218-21, and non-volatile content is determined after 3 h at 150 °C using ISO 3251:2019. Hydrogen content is the critical release parameter because terminal Si–H controls the reactive balance in addition-cure compounding. A shift of 0.02 wt% active hydrogen is sufficient to move cure reversion, hardness, or pot life in formulations with a target SiH:vinyl ratio near 1.1. The envelope below is representative; the certificate of analysis issued for each batch remains the controlling document.
| Property | Release envelope | Test method |
|---|---|---|
| Appearance | Clear to slightly hazy liquid | Visual inspection |
| Viscosity at 25 °C | 20–100 mPa·s | ISO 3219:2021 |
| Active hydrogen content | 0.03–0.10 wt% | Alkali hydrolysis gas titration / supplier FTIR method |
| Volatile matter after 3 h at 150 °C | ≤2.0 wt% | ISO 3251:2019 |
| Density at 25 °C | 0.955–0.970 g/cm³ | ISO 1183-1:2019 |
| Refractive index nD at 25 °C | 1.400–1.405 | ASTM D1218-21 |
The structural consequence of terminal hydride placement is a constant functionality of 2. In addition cure, this low functionality becomes meaningful only when the vinyl source carries functionality greater than 2, such as branched vinyl gums or vinyl-functional MQ resins. In such systems, RH-H59 reacts stepwise to connect vinyl-functional structural units, generating longer elastically active chain segments between permanent junction points. The gel point is therefore shifted to higher vinyl conversion than in systems using side-chain methylhydrogen fluids with functionalities commonly above 5. The resulting network has a lower crosslink density at fixed SiH:vinyl ratio, which generally lowers Shore A hardness and raises low-rate elongation.
For low-hardness liquid silicone elastomers, the working SiH:vinyl ratio is often selected between 1.05 and 1.25. At ratios below 1.0, unreacted vinyl groups can remain as dangling defects that plasticize the matrix and increase compression set after aging. At ratios above 1.5, excess terminal Si–H can be moisture-sensitive and may undergo hydrolysis to silanol, especially in humid storage or during post-cure annealing. Differential scanning calorimetry according to ASTM E1356-23 typically shows a broader cure exotherm and lower peak heat flow for terminal hydride systems than for pendant hydride crosslinker formulations.
Platinum catalyst level interacts with this stoichiometric window. At 5–20 ppm Pt, terminal hydride formulations can build viscosity slowly, with gelation delayed to 60–120 s at 120 °C in moving-die rheometer tests. Higher Pt levels shorten gel time but can also promote hydrosilylation of residual silanol condensation by-products. The optimum should be established using a curemeter operated under ISO 6502-2:2018 or equivalent moving-die cure testing.
The following table summarizes directional differences at constant filler content and comparable total SiH:vinyl stoichiometry. Values should not be transferred between applications without measuring the cured network properties under the specific thermal schedule.
| Parameter | RH-H59 terminal hydride | Pendant hydride fluid |
|---|---|---|
| Si–H position | α,ω terminal | Random side-chain distribution |
| Hydride functionality per molecule | 2 | 5–30, depending on grade |
| Network role | Linear chain extension between vinyl-functional structural units | Branching and junction formation |
| Gel point at fixed catalyst level | Later; higher vinyl conversion required | Earlier; lower vinyl conversion required |
| Shore A at SiH:vinyl 1.1 | Lower | Higher |
| Elongation at break under ISO 37:2017 | Higher | Lower |
| Compression set after 22 h at 175 °C | May be lower when vinyl defects are minimized | May be higher in tightly crosslinked networks |
| Residual SiH moisture sensitivity | Moderate | Higher due to greater SiH density |
| Volatile by-product tendency after post-cure | Generally lower | Generally higher, depending on side-chain structure |
In liquid injection molding, a production mixing unit with a static mixer and 20:1 L/D reciprocating screw can process RH-H59 if the hydride is pre-dispersed into the vinyl-bearing component before platinum addition. Vacuum deaeration at −0.095 MPa for 5–12 min removes entrained air from the low-viscosity component mixture. At 25 °C, the catalyzed mixture may have a pot life of 4–12 h; in accelerated schedules at 40 °C, viscosity increase and gel formation can reduce working time to below 2 h. Mold temperatures from 120 °C to 150 °C are practical for cold-runner systems, while 180 °C reduces demold time but demands tighter control of runner cooling. Injection pressure is usually maintained in the 15–60 MPa range. On actual production lines, batch-to-batch hydrogen content variation can shift in-mold gel time by several seconds, so an on-line moving-die rheometer or equivalent cure monitor is used to adjust temperature rather than relying on a single machine setpoint.
In solvent-free addition-cure coating and release film processes, RH-H59 can lower formulation viscosity without adding an inert diluent. Coating head temperature is commonly held at 25–40 °C, and platinum catalyst dose is selected in the 20–100 ppm range. Cure in forced-air ovens at 120–150 °C with dwell times of 30–90 s is typical for thin-film silicone release coatings. The SiH:vinyl ratio is kept near 1.2 to minimize free hydride in the cured film. Residual terminal Si–H can hydrolyze over time and form silanol sites that increase adhesion to pressure-sensitive adhesives; release force measured by ASTM D3330/D3330M-24 can drift upward if the stoichiometric window is exceeded. Low-viscosity terminal hydride oil is more prone to misting at high coating speed than a higher-viscosity pendant fluid. Therefore, coating stations are enclosed and equipped with extraction at line speeds above 300 m/min, and the gap setting is reduced to avoid over-wetting. Published process data for this exact material at extreme line speed is limited; formulators should validate misting and release stability on pilot equipment.
Closed-container storage is recommended at 5–30 °C with dry air or nitrogen blanketing. At relative humidity above 60 %, the terminal Si–H groups can be hydrolyzed in the presence of trace acids or bases, generating hydrogen and silanol species that alter viscosity and refractive index. The fluid is incompatible with amine-based inhibitors, phosphines, sulfur-containing compounds, organotin species, and strong alkali. Even 0.1 ppm of a sulfur-based poison can suppress platinum cure in sensitive formulations. Mixing with condensation-cure silicone oils containing tin catalysts is not permissible because tin compounds can promote silanol condensation by-products and destabilize addition cure. Formulators using carbon black, epoxy components, or reclaimed silicone feedstock should screen the final compound by differential scanning calorimetry before scale-up. The product should not be exposed to strong oxidizers. A safety data sheet review is required before altering the process or packaging configuration.
Regulatory classification of the product in the European Economic Area is provided on the safety data sheet under the REACH regulation; users should confirm article or substance obligations for the finished formulation according to REACH and RoHS Directive 2011/65/EU before commercial release.
Post-cure annealing at 200 °C for 4 h is used in food-contact and low-volatile silicone formulations to remove catalyst residues and low-molecular-weight siloxanes. During annealing, residual Si–H can undergo thermal redistribution or oxidation if oxygen is not excluded. Headspace gas chromatography may detect cyclic siloxanes in the D3–D6 range; the contribution from terminal hydride fluid is generally lower than from pendant hydride fluids, but specific data for RH-H59 in all film thicknesses are limited. Nitrogen purging at 1–3 volume exchanges per hour is recommended to carry off volatile by-products and prevent discoloration. The heating rate should be limited to 2 °C/min from 150 °C to 200 °C for thick parts, as rapid heating can produce surface defects from volatile release.
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