I. Core Selection: Viscosity & Vinyl Content of Vinyl Silicone Oil

Option 1: Terminal Vinyl Silicone Oil (Mainstream, simple process, easy hardness control)

• Base Viscosity: 5000 mPa·s or 10000 mPa·s (5000 mPa·s is preferred for moderate crosslinking reaction rate with hydrogen-containing silicone oil, suitable for both mixing and casting processes; 10000 mPa·s is suitable for scenarios requiring higher raw rubber strength)
• Vinyl Content: 0.20~0.25 mol% (mole fraction, corresponding to approximately 0.6~0.75 wt% mass fraction)
  ✅ Core Basis: The crosslinking network formed by crosslinking with hydrogen-containing silicone oil at this content exactly matches Shore D 60 hardness, which is the standard terminal vinyl content range for industrial addition-cure silicone rubber with Shore D 60 hardness.

Option 2: Terminal Vinyl Silicone Oil + A Small Amount of Pendant Vinyl Silicone Oil (Optimize mechanical properties, more stable hardness)

• Main Agent: Terminal vinyl silicone oil (5000 mPa·s, 0.20~0.25 mol%), accounting for 90~95%
• Modifier: Pendant vinyl silicone oil (1000~5000 mPa·s, 1.0~2.0 mol%), accounting for 5~10%
  ✅ Function: Pendant vinyl groups provide additional crosslinking points, solving the potential "hardness fluctuation" after crosslinking of pure terminal vinyl silicone oil, while improving the tensile strength and tear strength of silicone rubber without affecting the core Shore D 60 hardness.

❌ Avoidance Range

• Viscosity ＜ 3000 mPa·s: The crosslinked system is too soft and prone to shrinkage, making it difficult to reach Shore D 60;
• Viscosity ＞ 20000 mPa·s: Poor fluidity of raw rubber, difficult mixing, requiring a large amount of plasticizer, leading to low hardness and reduced mechanical properties;
• Vinyl content ＜ 0.15 mol%: Insufficient crosslinking density, with a maximum hardness of only Shore D 50~55, failing to meet the standard;
• Vinyl content ＞ 0.30 mol%: Excessive crosslinking, hardness exceeding Shore D 65, and the products become brittle with reduced elasticity.

II. Matching Selection of Hydrogen-Containing Silicone Oil (Crosslinking Agent, Key Matching)

• Hydrogen Content: 0.18~0.22 wt% (medium-low hydrogen content, suitable for medium-high crosslinking density, avoiding excessively fast crosslinking)
• Base Viscosity: 100~500 mPa·s (low viscosity, easy to disperse, good miscibility with vinyl silicone oil)
• Addition Ratio: Based on the above molar ratio, for terminal vinyl silicone oil with 5000 mPa·s/0.20 mol%, the addition amount of hydrogen-containing silicone oil (0.20 wt% hydrogen content) is approximately 1.0~1.2 phr (1.0~1.2 parts per 100 parts of vinyl silicone oil).

III. Industrial Grade References (Direct Procurement Adaptation, Main Domestic Manufacturers)

IV. Supplementary Process Points (Ensure Shore D 60 Hardness Compliance, Avoid Actual Measurement Deviation)

1. Unfilled pure rubber vs Filled rubber: The above selection is a filler-added (fumed silica) scheme (industrial mainstream, all Shore D 60 silicone rubbers contain fumed silica), with a fumed silica addition amount of approximately 40~50 phr (fumed silica with a specific surface area of 200~300 m²/g). For unfilled pure rubber, the vinyl content needs to be increased to 0.30~0.35 mol%, but pure rubber with Shore D 60 hardness has no practical value and is not recommended in industry.
2. Catalyst: Platinum catalyst (chloroplatinic acid complex) is used with an addition amount of approximately 5~10 ppm (platinum content). Insufficient amount leads to incomplete reaction, while excessive amount easily causes product yellowing.
3. Vulcanization Conditions: 120~150℃ × 5~10 min (thermal vulcanization), followed by post-curing at 200℃ × 2 h (remove low-molecular-weight substances, ensure hardness stability, with an actual measurement deviation of ≤±1D).
4. Diluent: Do not add an excessive amount of low-viscosity silicone oil (e.g., 100 mPa·s terminal vinyl silicone oil), otherwise the crosslinking density will be reduced and the hardness will decrease. If fluidity adjustment is needed, the addition amount shall be ≤ 3 phr.

V. Hardness Fine-Tuning Scheme (Rapid Correction When Actual Measurement Is Too Soft/Hard)

1. Actual hardness Shore D 55~58 (Too soft): ① Increase the addition amount of hydrogen-containing silicone oil to 1.2~1.4 phr (ensure Vi:H=1.2:1); ② Supplement 0.5~1.0 phr of pendant vinyl silicone oil (1.5 mol%).
2. Actual hardness Shore D 62~65 (Too hard): ① Reduce the addition amount of hydrogen-containing silicone oil to 0.8~1.0 phr; ② Add 1~2 phr of low-vinyl silicone oil (0.10 mol%, 5000 mPa·s) to dilute the crosslinking density.

专业术语注释（统一行业译法）

1. Shore D 60：邵氏 D 型硬度 60 度（橡胶硬度专用表述，缩写 Shore D 60）
2. phr：parts per hundred resin，每百份树脂（橡胶工业常用添加量单位，直接保留缩写）
3. terminal vinyl silicone oil：端乙烯基硅油（核心译法，区别于 pendant vinyl silicone oil 侧乙烯基硅油）
4. addition-cure silicone rubber：加成型硅橡胶（对应缩合型 condensation-cure silicone rubber）
5. crosslinking density：交联密度
6. fumed silica：气相法白炭黑（工业通用译法，区别于 precipitated silica 沉淀法白炭黑）
7. post-curing：后硫化（也作 secondary vulcanization，化工行业均通用）
8. chloroplatinic acid complex：氯铂酸络合物（铂催化剂主流品类）