| HS Code | 151578 |
| Product Name | Vinyl Silicone Oil RH-Vi305B |
| Chemical Name | Vinyl-terminated polydimethylsiloxane |
| Chemical Family | Vinyl silicone oil |
| Appearance | Colorless transparent liquid |
| Color | Colorless |
| Form | Liquid |
| Viscosity At 25 C | 5,000 mPa·s (typical) |
| Vinyl Content | 0.45 wt% (typical) |
| Volatile Matter 150 C 3h | ≤2.0 wt% |
| Refractive Index At 25 C | 1.403 (typical) |
| Specific Gravity At 25 C | 0.97 (typical) |
| Flash Point | >200 °C |
| Water Solubility | Insoluble |
| Solvent Solubility | Soluble in aromatic solvents such as toluene and xylene |
As an accredited Vinyl Silicone Oil RH-Vi305B factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | RH-Vi305B is supplied in 25 kg polyethylene-lined steel drums, sealed and clearly labeled for safe storage and transport. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with Vinyl Silicone Oil RH-Vi305B, securely stowed and sealed with required labels and shipping documents. |
| Shipping | Vinyl Silicone Oil RH-Vi305B is typically shipped in sealed drums or IBCs as a non-hazardous chemical, subject to local regulations. Keep containers closed, dry, and protected from sunlight and contamination. Confirm packaging, labeling, and transport classification against the current SDS before shipment. |
| Storage | Store Vinyl Silicone Oil RH-Vi305B in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, flames, and strong oxidizers. Keep containers tightly closed, correctly labeled, and protected from moisture and contamination. Use compatible containers and maintain spill containment. Do not smoke or use ignition sources nearby. Follow the manufacturer’s safety data sheet and local regulations for storage, handling, and inspection. |
| Shelf Life | Vinyl Silicone Oil RH-Vi305B has a typical shelf life of 12 months when stored sealed in a cool, dry, well-ventilated place. |
Addition-cure liquid silicone rubber molding lines incorporating RH-Vi305B use the vinyl functionality of the fluid as a controlled crosslink site in platinum-catalyzed hydrosilylation. In two-part LSR systems, Part A and Part B are blended at a 1:1 pump ratio through a static mixer before injection into heated molds; the base polymer phase containing RH-Vi305B commonly represents 40–70 wt% of the total compound, while fumed silica at 15–30 wt% adjusts thixotropy and green strength. The SiH:SiVi molar ratio is held between 1.2:1 and 1.8:1 to balance crosslink density and limit residual hydride species that can hydrolyze under steam exposure. Process windows remain narrow because barrel cooling below 25°C prevents premature gelation, mold temperatures are controlled within ±5°C of the 160–190°C setpoint, and injection pressures of 8–20 MPa on LSR-specific injection units with clamp force between 1500 kN and 3000 kN are typical for multicavity closures. Batch-to-batch viscosity drift above 5% against the certified value alters the 1:1 pump ratio and produces soft or hard spots in multicavity molds. The platinum catalyst is poisoned by tin-based condensation-cure residues and amine-containing mold release agents; production lines must be segregated from condensation-cure RTV operations. Compliance for medical-grade output requires batch certificates against ISO 10993-5:2009 for cytotoxicity and ISO 10993-10:2013 for skin sensitization, while food-contact silicone elastomers reference FDA 21 CFR 177.2600 and BfR Recommendation XV. Property verification after post-cure at 200°C for 4 h uses ASTM D412-16 for tensile strength, ASTM D2240-15 for Shore A hardness, and ISO 2781:2018 for density. Finished components include infusion valve membranes, autoclavable O-rings, respiratory mask cushions, and infant bottle nipple seals.
In high-consistency rubber compounding, RH-Vi305B functions as a reactive plasticizer and vinyl-content modifier rather than as a primary gum. Addition levels of 3–8 phr reduce Mooney viscosity ML(1+4) 100°C by approximately 5–15 MU in a 40 phr fumed silica compound, which lowers dump temperature during two-roll milling to below 110°C and shortens mix cycles on a 25 mm co-rotating twin-screw extruder with L/D 44:1. When the addition ratio exceeds 10 phr, tear strength measured according to ASTM D624-00(2020) typically falls below 15 kN/m in lightly filled gum because the abundant terminal vinyl groups increase crosslink density beyond the entanglement-dominated toughness plateau. This is the critical threshold where compression set improves but crack growth resistance declines, a cliff-edge effect observed on peroxide-cured HCR lines using 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane at 1.0–1.5 phr. Production equipment includes open two-roll mills with friction ratio from 1:1.15 to 1:1.25 and press cure at 170–190°C for 10–15 min, followed by post-cure in hot air ovens at 200–230°C for 2–4 h. Compliance is documented against ISO 37:2017 for tensile stress-strain properties, ISO 815-1:2014 for compression set, and ASTM D2240-15 for hardness. Terminal products include extruded dairy tubing, calendered sheet for food-contact conveyor belts, molded bakeware seals, and automotive turbocharger hoses. In applications requiring repeated steam sterilization, the formulation must retain tensile strength above 7 MPa after 100 autoclave cycles at 121°C, a requirement that excludes RH-Vi305B loadings above 8 phr because hydrolytic reversion accelerates in the silicone network.
When a solvent-free UV-cure release coating is run below 1000 mPa·s at 25°C, RH-Vi305B serves as a vinyl-functional reactive diluent that is consumed by radical-mediated addition with a multifunctional thiol crosslinker under UV exposure. A recommended addition range of 10–30 wt% of coating solids reduces viscosity without increasing extractables after cure. Roll-to-roll processing on a five-roll gravure coater at line speeds between 100 m/min and 300 m/min requires UV doses of 200–600 mJ/cm² in the UVC band, and oxygen inhibition is controlled by nitrogen inerting to residual oxygen below 50 ppm in the curing chamber. Because RH-Vi305B contains no thiol group, its terminal vinyl functionality is consumed only when the photoinitiator concentration exceeds 3 wt% of the formulation; lower photoinitiator loadings leave unreacted vinyl species that migrate to the adhesive interface and raise subsequent peel values above 10 cN/in. Compliance for food-contact release liners is evaluated under FDA 21 CFR 176.170 for paper and paperboard components and BfR Recommendation XXXVI for paper and board, while adhesive performance is characterized by FINAT FTM 3 at a 180° peel angle and 300 mm/min peel speed. Finished articles include polyester release liners for medical dressings, glassine liners for pressure-sensitive label stock, and polycoated kraft liners for envelope adhesives. In high-speed label converting, the cured silicone layer must achieve a thickness of 0.8–1.5 µm and a residual vinyl content below 5% of the original value, as measured by FTIR disappearance of the vinyl absorbance at 1595 cm⁻¹, to prevent blocking on the rewind reel. Published data for this exact photoinitiator-vinyl silicone oil pair is limited, so pilot coating trials are required before full-width production.
Potting and encapsulation processes using RH-Vi305B as the vinyl-functional base fluid in addition-cure gels demand strict control of the SiH:SiVi ratio between 0.8:1 and 1.5:1, because an excess of hydride crosslinker produces volatile hydrogen and low-molecular-weight silane species that condense on LED optics. Formulation addition ratios of 20–50 wt% of the resin component are typical for optical clarity applications, with the balance composed of methylhydrosiloxane crosslinker, a platinum catalyst inhibited by tetramethyltetravinylcyclotetrasiloxane at 0.05–0.2 wt%, and a reinforcing fumed silica treated with hexamethyldisilazane to maintain transparency. Vacuum degassing at −0.095 MPa for 15–30 min before meter-mix dispensing through a 24-element static mixer reduces entrapped air bubbles that otherwise cause dielectric breakdown. Cure schedules commonly step from 60°C for 30 min to 150°C for 4 h, and the post-cure stage removes volatile cyclic siloxanes to meet total outgassing thresholds below 0.1% by mass under ASTM E595-15 collected volatile condensable material testing. Compliance documentation includes UL 94 V-0 classification for flame resistance, IEC 60216-1:2013 for thermal endurance, and IPC-CC-830B for printed circuit board conformal coating qualification. Terminal products are LED module encapsulants, sensor potting compounds, power supply sealing gels, and photovoltaic junction box fillers. A processing limitation is moisture sensitivity: when ambient RH exceeds 60%, the silica surface adsorbs water that hydrolyzes the hydride crosslinker and shifts the gel hardness by 5–10 Shore 00 points, requiring either pre-dried filler or nitrogen-blanketed mixing.
During rotary screen printing of silicone inks, RH-Vi305B functions as a non-volatile reactive diluent that lowers high-shear viscosity into the printable window of 20–40 Pa·s at 10 s⁻¹, measured with a cone-and-plate rheometer according to ISO 3219:1993. Addition levels between 5 wt% and 15 wt% of the total ink formulation are used for fabric coatings that must withstand repeated washing without loss of elasticity; lower additions fail to correct pseudoplasticity on mesh counts above 100 threads/cm, while higher additions increase tack transfer to the squeegee and reduce print definition. The downstream process runs on rotary screen carousels at 40–80 m/min with mesh tension controlled to 25–35 N/cm, followed by thermal cure at 150–180°C for 30–90 s in forced-air ovens. Compliance for textile contact is evaluated according to Oeko-Tex Standard 100 Annex 4 Class I requirements, while European restrictions under REACH Annex XVII entries 50 and 51 apply to residual polycyclic aromatic hydrocarbons and phthalate content. Finished product types include anti-slip silicone sock grips, screen-printed logos on athletic apparel, elasticated waistband coatings, and silicone patches on medical compression garments. In textile lines processing dark polyester substrates, the addition of RH-Vi305B above 12 wt% can plasticize the silicone film sufficiently to reduce wash fastness below grade 4 in ISO 105-C06:2010 testing, a threshold that is observed as film delamination after 20 machine wash cycles at 40°C.
Cable insulation lines processing silicone rubber containing RH-Vi305B typically extrude on a 90 mm single-screw extruder with L/D 20:1 and a low-compression screw design, because high screw compression generates frictional heat that advances scorch time beyond the safe processing window. Addition levels of 2–10 phr are introduced to reduce compound viscosity and enable continuous hot-air vulcanization at 250–320°C with line speeds from 30 m/min to 150 m/min, depending on insulation wall thickness. The production process uses a crosshead die with pressure held below 25 MPa to avoid die swell fluctuations caused by vinyl silicone oil migration under high shear. Rotorless curemeter testing according to ISO 6502-2:2018 records ts2 scorch times above 45 s at 160°C for formulations containing less than 5 phr RH-Vi305B; at 10 phr the ts2 value may shorten to 35 s, which narrows the safe extrusion window and requires barrel cooling at 40–60°C. Electrical and safety compliance is verified against IEC 60245-1 for rubber-insulated cables, UL 1581 for reference test methods, and EN 50363-1:2005 for insulating compounds. Terminal products include high-temperature appliance lead wire, automotive engine harness sleeving, heating cable jackets, and submersible pump motor cable. In combustion-critical applications, formulations containing RH-Vi305B must still pass vertical flame testing to UL 94 V-0 with total flaming time below 50 s across 5 specimens, a constraint that restricts the vinyl silicone oil content to the lower end of the stated range unless antimony trioxide or aluminum hydroxide is added at 20–40 phr.
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Vinyl Silicone Oil RH-Vi305B is a linear dimethylpolysiloxane fluid bearing terminal vinyl groups at both chain ends. The terminal Si–CH=CH2 architecture allows the fluid to function as a reactive chain extender in platinum-catalyzed addition-cure silicone systems rather than as a non-functional diluent. The product is supplied as a clear, colorless liquid with a representative viscosity of 300 ± 50 mPa·s at 25 °C, a vinyl content of 0.30 ± 0.05 wt% determined by iodine monochloride titration, and a volatile matter content not exceeding 1.0 wt% when tested in a forced-air oven. These values are typical of the RH-Vi305B grade; the manufacturer’s certificate of analysis remains the controlling document for any production batch.
In a two-part formulation, the terminal vinyl groups react with silicone hydride crosslinkers in the presence of a platinum(0) or platinum(II) catalyst. The resulting network properties depend on the SiH:vinyl molar ratio, which is commonly held between 1.2:1 and 1.8:1 for balanced cure. Excess hydride can promote post-cure hydrogen evolution; insufficient hydride leaves unreacted vinyl groups that reduce oxidation resistance and increase surface tack after oven cure.
In a pendant-vinyl silicone oil, methylvinylsiloxane units are distributed along the siloxane backbone. Hydrosilylation with a methylhydrogenpolysiloxane crosslinker therefore creates multiple short-chain branches near each polymer chain, increasing crosslink density and raising hardness. In RH-Vi305B, the vinyl groups are located at the two chain termini; the hydrosilylation reaction proceeds primarily as linear chain extension, forming longer inter-crosslink segments. At the same vinyl group addition level, the terminal architecture produces a softer network with lower storage modulus and greater elongation at break, while the pendant architecture produces higher tensile modulus and reduced compression-set resistance. This distinction is relevant for liquid silicone rubber formulations in which a 5–10 Shore A durometer reduction is required without decreasing filler loading. No single architecture is universally superior; the selection depends on whether the compound must absorb stress through chain extension or resist deformation through network density.
On coating lines and injection molding machines, the low viscosity of RH-Vi305B permits solvent-free metering with gear pumps or diaphragm pumps and reduces the pressure needed to pass through static mixers. In a 32-element static mixer with a 12 mm internal diameter, neat fluid at 25 °C typically shows a pressure drop below 0.8 MPa at a flow rate of 2 L/min; this is an equipment-level estimate, not a batch guarantee. When 20 wt% fumed silica is dispersed, the compound viscosity rises into the range 8,000–12,000 mPa·s, and the static mixer discharge pressure may exceed 2.5 MPa depending on mixer design and temperature. Preheating the two components to 35–40 °C lowers viscosity and reduces the risk of cavitation in gear pumps. For filled systems, published data for this specific configuration is limited; therefore, rheological profiling with the actual mixing head is required before line-speed qualification.
The following values are representative for RH-Vi305B and are not intended to replace a batch-specific certificate of analysis. Test methods are cited as recognized procedures where applicable; vinyl content is typically determined by iodine monochloride titration because the terminal vinyl groups absorb iodine quantitatively in chloroform solution.
| Parameter | Method | Representative Range or Limit |
|---|---|---|
| Appearance | Visual inspection, 100 mL sample | Clear, colorless, free of visible particles |
| Viscosity at 25 °C | ISO 3219:2021 | 300 ± 50 mPa·s |
| Vinyl content, Si–CH=CH2 | Iodine monochloride titration | 0.30 ± 0.05 wt% |
| Volatile matter | ISO 3251:2019, 105 °C, 2 h | ≤1.0 wt% |
| Specific gravity at 25 °C | ASTM D4052 | 0.965–0.975 |
| Refractive index nD25 | ISO 2807 | 1.4000–1.4050 |
| Total acidity | Titration with alcoholic KOH | ≤0.01 mg KOH/g |
The viscosity value is measured on a rotational viscometer at a controlled shear rate. Batch-to-batch variation in vinyl content should be maintained below ±0.05 wt% to avoid inconsistent crosslink density in addition-cure silicone rubber. If the vinyl content drifts upward, the network becomes more heavily crosslinked and hardness increases; if it drifts downward, cure may be incomplete and the cured surface may remain tacky.
RH-Vi305B can be compared with two common alternatives: a side-chain vinyl fluid and a higher-viscosity terminal vinyl fluid. The following comparison is based on typical industrial data for silicone fluids of similar molecular technology and is not a direct specification comparison.
| Characteristic | RH-Vi305B, low-viscosity terminal vinyl | Side-chain vinyl fluid | Higher-viscosity terminal vinyl fluid |
|---|---|---|---|
| Representative viscosity at 25 °C | 300 ± 50 mPa·s | 800–1,200 mPa·s | 10,000–20,000 mPa·s |
| Vinyl placement | Both chain ends | Pendant along chain | Both chain ends |
| Primary network effect | Chain extension with lower modulus | Increased crosslink density with higher hardness | Chain extension with higher toughness |
| Volatile matter | ≤1.0 wt% | ≤0.5 wt% | ≤2.0 wt%; published data for this specific configuration is limited |
| Typical use in LSR | Reactive diluent and soft segment | Hardness modifier | Toughening additive |
In practice, side-chain vinyl fluids are selected when the formulation requires high hardness and low compression set; terminal vinyl fluids are selected when low-temperature flexibility and lower modulus are more important. The higher-viscosity terminal fluids are used for heat-cured rubber applications where toughness and tear strength are critical. The choice is not determined by the fluid alone but by the ratio of hydride crosslinker, filler surface treatment, and curing schedule.
Formulation calculations for addition-cure silicone use the vinyl content to set the required amount of hydride-functional crosslinker. For a compound containing 20 phr RH-Vi305B and a base polymer with terminal vinyl groups, the total reactive vinyl concentration is the sum of the vinyl groups on the fluid and the base polymer. The stoichiometric hydride requirement is obtained by multiplying the total vinyl molar content by the selected SiH:vinyl ratio, typically from 1.2:1 to 1.8:1. A ratio of 1.2:1 produces softer elastomers with lower residual hydride odor, while a ratio above 1.5:1 improves hardness and cure completeness but can generate hydrogen gas when exposed to moisture or high temperature. In closed molds, excess hydride above 1.8:1 is not recommended for thick sections because gas evolution can create internal voids.
Cure kinetics in platinum-catalyzed systems are influenced by inhibitor type, catalyst concentration, and mold temperature. Typical conditions use 5–10 ppm platinum and 0.05–0.15 phr 1-ethynylcyclohexanol inhibitor to control pot life. At 120 °C, a 2 mm sheet may reach t90 in 5–10 min, depending on filler moisture and inhibitor level. Differential scanning calorimetry can confirm the hydrosilylation exotherm; formulations with RH-Vi305B require the same cure process validation as any other vinyl-functional silicone fluid.
Because RH-Vi305B contains reactive terminal vinyl groups, it is incorporated into the silicone network after vulcanization. This behavior is different from that of non-reactive dimethylsilicone oil, which remains as a free plasticizer and can migrate to the surface of cured parts. In applications such as silicone rubber rollers, gaskets, and sealing profiles, this migration can cause surface haze, reduced adhesion to substrates, and changes in friction coefficient. The use of a terminal vinyl fluid reduces extractable low-molecular-weight siloxanes only if the cure is driven to high conversion. A post-cure cycle of 4 h at 200 °C in a ventilated oven is a common industrial condition for removing residual volatile siloxanes from 2 mm sheets; extraction tests using 50% ethanol at reflux for 2 h can then be used to monitor the extractable fraction. For food-contact or medical elastomers, the final article must be tested according to the relevant regional regulation, such as FDA 21 CFR 177.2600 or EU Directive 1935/2004, before commercialization. The RH-Vi305B product itself does not confer regulatory approval to a finished silicone article.
In high-speed release-coating lines, the amount of RH-Vi305B added to the base polymer varies with the desired release force and the coating weight. Addition levels between 10 phr and 30 phr of base silicone polymer reduce the mixed viscosity and can shift release force from low peel to medium peel values when measured by a 180° peel test at 300 mm/min. The data are indicative only; the release force depends on the coater type, cure temperature, and the pressure-sensitive adhesive used. The terminal vinyl fluid also slows moisture-related viscosity build in filled compounds by lowering the initial compound viscosity before the addition of fumed silica, though excess amounts above 30 phr may lead to softer cured films and lower cohesive strength.
On a roll-to-roll coating line with a five-roll gravure head, the low dynamic surface tension and Newtonian character of the unfilled RH-Vi305B assist in maintaining uniform wet film thickness across widths up to 1,200 mm. The product’s viscosity below 350 mPa·s at 25 °C allows line speeds of 5–40 m/min to be achieved without solvent addition, but the actual speed depends on coating head geometry, substrate roughness, and the desired coat weight. For multi-layer release films, the silicone layer is typically coated at 0.8–1.5 g/m²; additional rheological adjustment may be needed if the coat weight is below 0.5 g/m². The vinyl content of 0.30 ± 0.05 wt% must be verified for each batch to avoid drift in release force across the roll.
Fumed silica dispersion in low-viscosity vinyl fluids is more energy-intensive than in high-viscosity gums because the initial shear transfer is lower. In a planetary mixer equipped with a wall scraper and high-speed disperser, silica addition should be split into 3–4 increments with a tip speed above 10 m/s for the final dispersion step. The low initial viscosity of RH-Vi305B can delay the onset of a coherent compound, causing silica dust formation if the feed rate is too high. Once the filler surface is wetted, the viscosity increases sharply, and the mixture transitions from a fluid-like suspension to a paste-like compound. This is a normal process, but it requires closed mixing equipment to reduce particle exposure and humidity uptake.
RH-Vi305B is designed for addition-cure platinum systems and does not hydrolyze under moisture-cure conditions. It should not be used as the primary functional fluid in condensation-cure silicone sealants; in those systems, it will remain unreacted unless an additional peroxide or thiol-ene cure step is added. Amine-based release agents, sulfur-containing compounds, and certain organotin species should be kept separate from the component containing the platinum catalyst because they can poison hydrosilylation activity. In filled compounds exposed to relative humidity above 60%, vacuum drying at 90–100 °C under -0.09 MPa for 2 h is recommended before addition of the platinum catalyst; otherwise, water adsorbed on filler surfaces may reduce catalyst efficiency and produce surface defects. Storage under sealed containers at 5–35 °C is recommended, with a use-before period assigned by the manufacturer. Avoid prolonged heating above 80 °C to reduce the risk of viscosity drift and gelling in the presence of peroxide impurities.
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