Silicone

Selecting the right silicone grade is critical for performance and safety. Food Grade silicone must comply with FDA 21 CFR 177.2600 or LFGB standards for kitchenware. Medical Grade requires ISO 10939 or USP Class VI certification for biocompatibility. For industrial use, focus on Shore A Hardness (typically 30-70) and Temperature Resistance, ensuring the material can withstand ranges from -60°C to 250°C without losing elasticity.

Buyers should request a Technical Data Sheet (TDS) to verify Tensile Strength (MPa), Elongation at Break (%), and Tear Strength (kN/m). For liquid silicone rubber (LSR), check the Viscosity and Mixing Ratio (usually 1:1). Ensure the supplier provides a Material Safety Data Sheet (MSDS) to confirm chemical stability and handling requirements.

Platinum-cured silicone is higher quality, offering superior clarity, no yellowing, and no toxic by-products, making it ideal for medical and food industries. Peroxide-cured silicone is more cost-effective and offers good mechanical properties but may have a slight odor and bloom over time. For high-end consumer goods, Platinum-cured is the industry benchmark.

To enter the EU market, silicone must be REACH and RoHS compliant, ensuring it is free from restricted substances like phthalates or heavy metals. For the US market, TSCA (Toxic Substances Control Act) compliance is necessary. Always ask the supplier for updated third-party lab reports (SGS or TUV) dated within the last 12 months.

Some suppliers add calcium carbonate or paraffin oil to reduce costs, which compromises durability. To prevent this, request a sample and perform a 'stretch test' (pure silicone does not turn white when stretched) or a burn test (pure silicone leaves white ash, not black). Use Made-in-China.com's Secured Trading services to hold payment until quality is verified.

Silicone prices fluctuate with crude oil and silicon metal markets. Negotiate based on volume tiers (e.g., 1-ton vs. 5-ton pricing) and seek fixed-price contracts for 6-month periods to avoid volatility. Standard lead times are 10-15 days; always include a penalty clause for late delivery in your Proforma Invoice (PI).

Liquid Silicone Rubber (LSR) is often classified as 'sensitive' cargo. Ensure the supplier uses UN-approved steel drums to prevent leakage. For solid high-consistency rubber (HCR), ensure vacuum packaging to prevent moisture absorption and contamination. Confirm that the HS Code (typically 391000) is correctly declared to avoid customs delays.

Always verify the supplier's Business License and Export Qualification on Made-in-China.com. Utilize Audit Reports provided by third-party agencies like SGS or Intertek. Never wire full payments upfront; use a 30% deposit and 70% balance against the Bill of Lading (B/L) or an Irrevocable Letter of Credit (L/C) for large-scale industrial orders.