WACKER SILRES HK46 25kg – High-Temperature Silicone Resin, Heat-Resistant and Non-Stick Binder up to 600°C with Food Contact Compliance

SILRES HK46 is an advanced, high-molecular-weight methyl silicone resin supplied as a 50 wt.% solution in a xylene/n-butanol mixture (4:1 ratio). The product has been designed as a high-quality binder for heat-resistant coatings and thermally stable non-stick coatings.

Main Properties The resin features an excellent balance of flexibility, hardness, heat resistance, and curing speed. It has low viscosity (40–60 mm²/s at 25 °C) and a density of approximately 1.01 g/cm³. It provides rapid air-drying to tack-free films that offer temporary corrosion protection. Due to limited compatibility, the product is preferably used as a sole binder (it typically mixes only with other methyl silicone resins). It also features excellent hydrophobicity and high corrosion resistance.

Technical Parameters

• Appearance: clear, colorless to slightly yellow liquid

• Solids content: approx. 50 wt.% (1 h at 200 °C)

• Flash point: 26 °C

• Ignition temperature: 435 °C

• Solvent: xylene / n-butanol (4:1)

Applications

• Heat-resistant coatings: Suitable for paints used on fireplaces, mufflers, exhaust systems, engine parts, boilers, furnaces, oven inserts, chimneys, barbeques, electric/gas heaters, and incinerators. In combination with appropriate pigments (e.g., aluminum pigments for silver-grey colors or black iron/manganese oxides and spinels for black color) and platelet-shaped fillers (talc, mica), these formulations can achieve thermal stability up to 600 °C.

• Non-stick coatings: Used in technical coatings and bakeware (food contact) for professional or industrial use. Typical formulations contain additives such as SILFAR 350 (3–5 wt.%) and titanium(IV) n-butoxide (0.5–1 wt.%) to accelerate the formation of durable silicone coatings.

• Other applications: Industrial coatings as well as marine and protective coatings.

Application and Curing Guidelines Application can be carried out by spraying, dipping, or brushing. The coatings dry at room temperature, but to achieve full mechanical and solvent resistance, they require heat-curing above 150 °C (recommended curing is 250 °C for 30 minutes). Metal substrates should be degreased and sandblasted prior to painting.

Storage The product must be stored in a dry and cool place, in tightly closed original containers, protected against moisture. Contact with moisture or inappropriate metal containers containing tin may lead to product gelation.