In the addition-cure LSR optical-grade spectrum, the "phenyl molar embed ratio (10±3%)" and "A:B=9:1 asymmetric ratio (Pt enriched in minor B)" jointly dictate cured RI lift (PDMS 1.41 → ~1.50-1.51 at 10% phenyl), long-term blue/UV yellowing boundary, and optical coupling efficiency between LED chip (GaN RI~2.4) and phosphor layer. Pure VMQ-LSR is clear but RI 1.41—high total internal reflection loss at high-power LED interface; epoxy yellows in 1000-2000h blue exposure. As high-power LED encapsulation, PV junction-box potting, aerospace wide-temp optical windows, and TIMs demand "colorless-pale-yellow transparent, 10±3% phenyl, 9:1 easy-mix, pot-life ≥12h, addition no-byproduct, yellow-free + hydrophobic lubricious," sourcing an A/B both colorless-pale-yellow, 3218-1-1 A4000-6000/B3000-6000, 3218-1-2 A8000-10000/B7000-10000mPa·s, 25℃ pot-life ≥12h product has become the core gap for domestic optical phenyl LSR localization.
Addressing this "phenyl embed-optics" pain point,
Anhui IOTA Silicone Oil Co., Ltd. (IOTA) officially launches
Phenyl Liquid Silicone Rubber IOTA BLSR 3218 Series (3218-1-1 mid-visc, 3218-1-2 high-visc). Characterized by "colorless to light-yellow transparent, phenyl 10±3%, A:B=9:1 (mass), 25℃±2℃ pot-life ≥12h, 3218-1-1 A4000-6000/B3000-6000mPa·s, 3218-1-2 A8000-10000/B7000-10000mPa·s, Pt addition no-byproduct, recommend staged cure (100℃×1h+150℃×3-4h), for LED/PV/aerospace/TIM," and backed by "10% phenyl RI-lift anti-yellow + 9:1 Pt-side enrich anti-poison + dual-visc select," it serves as the "phenyl silicone anchor" for LED encapsulant, PV junction potting, optical lens molding, and thermal-interface base gum.
Molecular Architecture: 10% Phenyl RI-Lift + 9:1 Pt-Side Enrich + Addition No-Byproduct 3D Logic
The core competitiveness of IOTA BLSR 3218 stems from its "vinyl poly(methyl/phenyl)siloxane base (A with Pt) + low-H poly(methyl/phenyl)siloxane crosslinker (B) + optical-grade hydrophobic fumed silica" asymmetric two-part architecture:
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10±3% Phenyl RI-Lift Anti-Yellow: Phenyl side-chain high polarizability lifts cured RI from 1.41 to 1.50-1.51 (10% window), matching mainstream LED silicone RI; phenyl conjugation disperses blue/UV energy—after 150℃×1000h or blue 50,000h, transmittance >98%, Δb*<1.5, far better than epoxy (yellows 1000-2000h).
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9:1 Pt-Side Enrich Anti-Poison: A:B=9:1 means Pt pre-mixed in 10% B side; main meter pumps A (9), B micro-dosed—Pt concentration higher in B, less long-term self-activation with inhibitor during storage; field 9:1 mass metering needs slightly higher precision but wider tolerance band.
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Addition No-Byproduct + Optical Clarity: Pt hydrosilylation releases no water/alcohol, no bubbles/no cure shrinkage, no chip passivation damage; low-aggregate hydrophobic fumed silica keeps haze<1%, 400-800nm >92% transmittance.
Performance Leap: From "VMQ 1.41 TIR" to "Phenyl 10% 1.50 Couple"
Incorporating IOTA BLSR 3218 enables qualitative leaps:
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High-Power LED: 3218-1-1 (mid-visc) encapsulates 1W+ blue chip, RI 1.50 couples GaN (2.4)/phosphor (~1.6), TIR loss cut, light extraction +5-8% vs VMQ; 150℃×1000h brightness loss <5%, no yellow.
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PV Junction Box: 3218-1-2 (high-visc) pots bypass diode, -40~200℃ cycle, hydrophobic (WCA>100℃), UV 5-year no crack no yellow.
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Optical Lens/Lightguide: 3218-1-1 for thin-wall lens injection, 3218-1-2 for thick lightguide—transparent uniform, replaces some PC/PMMA (low Tg) duties.
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TIM & Aerospace: Blend AlN/BN for phenyl thermal grease (RI+heat balance), or satellite optical-window edge seal—wide-temp (-60~250℃) no yellow no crack.
Application Penetration: From LED Chip to PV Diode
IOTA BLSR 3218 covers sectors triply sensitive to "optical clear + yellow-free + wide-temp":
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LED Lighting: High-power encapsulant, phosphor-dispersion carrier, lens injection, headlamp module edge.
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PV New-Energy: Junction-box potting, bypass-diode encapsulate, PV lens.
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Aerospace/Military: Optical instrument seal, wide-temp radome, military indicator encapsulate.
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TIM/Electronics: Phenyl thermal-grease base gum, high-end IC buffer encapsulation.
IOTA Technical Guide: 9:1 Meter, Staged Cure
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Mix: A:B=9:1 by mass (not 1:1, use dual-meter pump or precise weigh), static mixer, vacuum degas (-0.095MPa×3-5min); pot-life ≥12h@25℃±2℃, use within 12h.
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Cure: Recommend staged—100℃×1h precure (demold) + 150℃×3-4h postcure (final hardness/optical stable); thin LED dotting can 120℃×30min+150℃×1h accelerate.
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Substrate: LED leadframe (PPA/EMC/ceramic) clean oil-free; PV Cu/Al suggest plasma or IOTA 3954 primer.
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Taboo Red Line: No N/P/S/amine/tin/lead-cadmium—Pt poison no-cure; phenyl better than epoxy but long sunlight still advise UV absorber; 3218-1-2 high-visc hand-mix traps air—must meter.
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Storage: Original A/B separate sealed (20kg/200kg drum per order); cool dry ≤32℃ (ref. same-family LSR ~9mo, follow factory COA); general chemical, uncured no eye contact.
Industry experts note that under Mini/Micro-LED efficacy race, PV 25-year weathering upgrade, and aerospace optical-window wide-temp trends, 10% phenyl addition LSRs are upgrading from "Dow OE/Momentive UVS/Shin-Etsu SER import followers" to "LED encapsulant yellow-free reference optical gum." IOTA BLSR 3218, with its "10±3% phenyl + 9:1 dual-grade (4-6k/8-10k visc) + pot-life ≥12h + addition no-byproduct" hard metrics,
fills the domestic supply chain gap for phenyl LSRs in LED/PV/aerospace optical encapsulation, providing a mass-producible path to replace imported Dow OE-6550, Momentive UVS 500 for downstream encappers and PV material plants. This confirms domestic optical LSRs are advancing steadily along "VMQ clear LSR → high-phenyl optical gum → 10% phenyl balanced anti-yellow type," with growing technical say in LED light-extraction and yellow-free key materials.
