Alkenylgroup containing polysiloxane copolymers and their use as anti-misting additives for silicone coating compositions

摘要

Alkenyl group-containing siloxane copolymers are used as antimisting additives in crosslinkable silicone coating compositions. The use of alkenyl group-containing siloxane copolymers (ASC) as antimisting additives in crosslinkable silicone coating compositions (XSCC) to reduce aerosol formation. ASC are obtained by (a) reacting a compound (1) of formula R<2>(CR<3>=CH2)x (I) containing at least 3 aliphatic double bonds with an organosiloxane (2) with terminal Si-bonded hydrogen atoms in presence of a hydrosilylation catalyst (3), using a ratio of (Si-linked H in 2):(double bonds in 1) = 1.3-10, to give a siloxane copolymer with Si-linked H, (b) reacting this product with an alpha , omega -dialkenyl-siloxane polymer (4) in presence of (3) using a ratio of (double bonds in 4):(Si-linked H) = 1.2-10 and optionally (c) equilibrating the product with an organopolysiloxane (OPS) (5) selected from linear OPS with terminal triorganosiloxy or hydroxyl groups, branched OPS (optionally with hydroxyl groups), cyclic OPS and copolymers with diorganosiloxane and mono-organosiloxane units. R<2> = a tri- or tetra-valent hydrocarbon residue, preferably with 1-25 C atoms and optionally also containing one or more separate oxygen, silicon and/or titanium atoms; R<3> = H or alkyl (preferably 1-6C alkyl); x = 3 or 4. Independent claims are also included for (1) XSCC with reduced aerosol formation, containing ASC, organosilicon compounds with aliphatic C-C multiple bonds, organosilicon compounds with Si-linked H atoms, hydrosilylation catalysts and optionally inhibitors; (2) formed products obtained by crosslinking these compositions; (3) a method for the production of coatings by applying XSCC to the substrate surface and crosslinking the coating; and (4) a method for the production of coatings which repel sticky materials by applying and crosslinking XSCC as in (3).