| 摘要 |
Curable laminating compositions comprise (a) a polyepoxide of the formula <FORM:1057463/C3/1> in which X is (-CH2-O2C-) or (-CH2O2CRCO2CH2-) or (-CO2RO2C-), R is an aliphatic hydrocarbon group of 2-6 carbon atoms or -OZ- or the radical of a polyoxyalkylene glycol, HOROH, of 2-6 carbon atoms, Z is an alkylene group of 2-6 carbon atoms and R1 is H or an alkyl group of 1 to 4 carbon atoms; (b) a polyoxyalkylene polyol of molecular weight from 750-2500 and of hydroxyl equivalent weight from 275 to 1250; (c) a glycol of hydroxy equivalent weight below 114; (d) a carboxylic acid anhydride of an aliphatic dicarboxylic acid having an ionization constant of at least 2 x 10-5 and melting at or below 65 DEG C., and (e) an organic tin catalyst. The polyepoxide forms 30 to 40% by weight of the polyepoxide and polyol and glycol: the polyol forms at least 85% by wt. of polyol and glycol: the glycol is present in amounts sufficient to impart to the cured composition a resin stiffness ( = the ratio of ultimate tensile strength to percentage elongation at failure at 25 DEG C. of 0.4-1.8 p.s.i.: the anhydride is present in an amount to provide 1.8-2.2 carboxyl groups per hydroxyl group of polyol and glycol: and the catalyst is present in amounts of 0.25-1.5 wt. per cent as tin based on the total weight of the laminating composition. Organic tin catalysts specified are SnII SnIV acylates, alkodxides, phenoxides cresoxides; the oxidized SnII acylates; and the SnIV mercaptides and organophosphates. The products are useful in laminating implosion caps to cathode-ray tubes. |
