Abrasion resistant coating compositions based on silane hydrolysates and aluminium compounds and corresponding abrasion and shock resistant coated articles

Hardenable composition for an abrasion resistant coating comprising the following constituents:

• A—a silane hydrolysate containing an epoxy group and three alkoxy groups, the latter groups being directly bonded to the silicon atom,
• B—a silane hydrolysate having formula (I):
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• where T1 and T2 are groups which will each react to give a OH group on hydrolysis of the silane of formula (I),
• Z1 and Z2 are organic groups bonded to the silicon atom by a Si—C bond which do not contain a group capable of reacting with the hydrolysed silanes present in the composition,
• C—colloidal silica,
• D—an aluminium compound selected from:
• aluminium chelates,
• compounds having formulated (III) or (IV)
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• (R′O)3-nAl(OSiR″3)n (IV)
• wherein:
• R and R′ are linear or branched alkyl groups with 1 to 10 carbon atoms,
• R″ is a linear or branched alkyl group with 1 to 10 carbon atoms, a phenyl group, a
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• group where R has the meaning given above, and n is a whole number from 1 to 3.