| 摘要 |
Crosslinkable silicone coating compositions are prepared from (1) organopolysiloxanes containing alkenyl groups and containing per molecule at least one unit <?in-line-formulae description="In-line Formulae" end="lead"?>O3-n/2RnSi-Y(SiRnO3-n/2)a (I),<?in-line-formulae description="In-line Formulae" end="tail"?> at least 2 units <?in-line-formulae description="In-line Formulae" end="lead"?>R1RbSiO(3-b)/2 (II),<?in-line-formulae description="In-line Formulae" end="tail"?> and units <?in-line-formulae description="In-line Formulae" end="lead"?>RcSiO(4-c)/2 (III),<?in-line-formulae description="In-line Formulae" end="tail"?> where R is a monovalent, SiC-bonded organic radical having 1 to 30 C atoms free from aliphatic carbon-carbon multiple bonds, R1 is an alkenyl radical having 2 to 4 C atoms, and Y is a divalent or trivalent organic radical having 1 to 30 C atoms, with the proviso that the organopolysiloxanes (1) contain units (II) in amounts wherein the concentration of alkenyl radicals R1 is less than 2 meq/g, (2) organopolysiloxanes containing Si-bonded hydrogen atoms, (3) a hydrosilylation catalyst, and (4) optionally, inhibitors. The compositions cure rapidly with few extractables and are very useful in preparing release coatings.
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