Optical Silicone Rubber

Comparable to leading global optical silicone brands for injection molding and encapsulation

• RI 1.41 to 1.54
• For optical injection molding and encapsulation
• High transparency and stable performance
• Custom formulation available

Newsil In Optical Silicone Industry

• Why Choose Newsil
• ✔ 20+ years of experience in silicone materials
• ✔ Specialized in optical silicone for LED, lenses and encapsulation
• ✔ Cost-effective alternative to leading global brands
• ✔ Fast sampling and engineering support

1. Stable optical performance
   Optical silicone offers very high and stable light transmission in the visible range, typically above 90–94% for clear grades at standard thickness, even after long‑term operation with high‑power LEDs.
2. Excellent environmental durability (UV, heat, humidity)
   Thanks to the inorganic Si–O backbone, optical silicone shows outstanding resistance to UV radiation, heat and moisture compared with common optical plastics such as PC or PMMA.
3. Precision molding capability
   As a liquid silicone material, optical silicone can be injection‑molded or cast into complex, high‑precision optical components with fine features and thin walls.

Choose the Right Optical Silicone for Your Project

• Typical RI 1.41 for Injection Molding/Encapsulation
• Higher RI 1.46 for Injection Molding
• High End RI 1.51 for Encapsulation

Refractive Index (RI)	Positioning / Characteristics	Typical Applications
RI 1.41	Low RI, close to common low‑index media	Optical encapsulation and protection, low‑index cladding, general light‑transmitting parts; used for anti‑reflection purposes or as an encapsulant.
RI 1.46	Medium RI, close to many optical glasses	Index matching to glass and optical fiber; bonding and transition layers between glass and silicone or other optical components.
RI 1.54	High RI, suitable for strong refraction and compact designs	Lenses and light guides that require higher light bending and stronger focusing in compact systems; can replace certain high‑index glass or plastic materials.

Optical Silicone RI 1.41

Optical Silicone RI 1.41 for Injection Molding

Features: Refractive Index 1.41/92% transmittance/hardness ranging from 40-80 shore A, for injection molding, comparable to LUMISIL LR 7601, KE-2061, Silopren LSR 7080J, SILASTIC MS-1003

Appearance	Density (g/cm³)	Viscosity (mPa·s, 25°C)	Hardness (Shore A)	Tensile Strength (MPa)	Elongation (%)	Tear Strength (kN/m)	Transmittance (%, 450 nm, 2 mm)
Colorless Transparent	1.04	40,000 ± 5,000	80 ± 3	9.5	75	14	92

Optical Silicone RI 1.41 for Encapsulation

Features: Low viscosity, suitable for optical encapsulation and potting, comparable to SYLGARD 184 ,Dow RTV615 ,ELASTOSIL RT 601, Shin-Etsu KE-103

Appearance	Viscosity A (mPa·s, 25°C)	Viscosity B (mPa·s, 25°C)	Mixing Ratio (A:B, by weight)	Working Time (25°C)	Hardness (Shore A)	Transmittance (%, 450 nm, 1 mm)	Tensile Strength (MPa)	Elongation at Break (%)	Tear Strength (kN/m)	Dielectric Strength (kV/mm)
A: Transparent Liquid / B: Transparent Liquid	4000 ± 400	40 ± 10	10 : 1	> 2 h	48 ± 3	> 98	> 5.2	> 120	> 2.3	≥ 18

Optical Silicone RI 1.46

Features: RI 1.46，for injetion molding，comparable to LUMISIL LR 3003, Nusil LS-6946

Appearance	Density (g/cm³)	Viscosity (×10⁴ mPa·s, 25°C)	Hardness (Shore A)	Tensile Strength (MPa)	Elongation (%)	Tear Strength (kN/m)	Refractive Index
Transparent	1.135	25	36	4.5	350	18	1.465

Optical Silicone RI 1.54

Features: High refractive index 1.54, low viscosity, suitable for optical encapsulation and potting, comparable to Dow OE-6630，WACKER LUMISIL 590

Appearance	Viscosity A (mPa·s, 25°C)	Viscosity B (mPa·s, 25°C)	Mixing Ratio (A:B, by weight)	Recommended Curing Process	Working Time (25°C)	Hardness (Shore D)	Transmittance (%, 450 nm)	Refractive Index
A: Transparent Liquid / B: Transparent or Translucent Liquid	20,000 ± 2,000	1,150 ± 200	1 : 1	Heat cure after dispensing, 150°C / 3 h	≥ 4 h	52 ± 3	> 95	> 1.53