APERFEICOAMENTO EM LAMINADOS RESISTENTES AO IMPACTO POR CHOQUE

1504198 Impact-resistant polycarbonate laminates GENERAL ELECTRIC CO 16 April 1975 [26 April 1974] 15707/75 Heading B5N In an impact-resistant adhesively-bonded laminate for use as a window or windscreen, the innermost layer is a polycarbonate layer of thickness at least 30 and less than 220 mils, e.g. 60-150 mils. having a relatively more brittle scratch-resistant coating of thickness up to 2 mils. on at least its exposed face. The layers may be bonded by a block polysiloxane-polycarbonate copolymer adhesive as defined below. Glass sheets may be strengthened or unstrengthened. Lamination may be carried out in an autoclave using a vacuum bag or ring; an adhesion primer may be used. Suitable scratch - resistant coatings are listed. In examples the following laminates are prepared from glass sheets (G) and polycarbonate layers having scratch-resistant coatings on the exposed faces only (A) or on both faces (B), or not coated (C) (figures represent thickness in mils.); (i) G125-C500-A125, (ii) A500-C500-B60, (iii) A250-C500-C500-B93, (iv) A250- C500-C500-A93, (v) A125-C375-C375- A125, (vi) G125-C250-A375 and (vii) A250- C500-A250; (v) may be used with either face inwards and (vi) and (vii) are comparison examples not within the invention. The adhesive may be 15-60 mils. thick and is prepared by reacting (A) a halogen chainstopped polydiorgarosiloxane composed of 5-200 siloxy units connected by Si-O-Si linkages and (B) a dihydric phenol where Z is H, halogen or lower alkyl and R is H, hydrocarbon or halohydrocarbon and phosgenating the reaction product.