Pratley Investments (proprietary) Limited

Pratley Investments Limited

Kimleigh George Pratley

Richard Grieves

A primer for the promotion of bonding of a first plastic substrate to a second plastic substrate, which plastic substrates may either be made of a plastics material which conventionally is difficult to bond or of a plastics material which conventionally is not difficult to bond, with an adhesive such as a cyanoacrylate, consists of a compound of the formula I: ##STR1## wherein --(CH.sub.2).sub.n -- is a straight or branched chain alkyl group of 1 to 6 carbon atoms inclusive; p, q, r and s are each independently 1 to 6 inclusive; and each R is independently --CH.sub.3 or --OH.

Adhesive primer

A two-component adhesive or sealing system which comprises a mixture of two components, a first component comprising a mixture of a constituent (a) being an amine curable epoxy resin, and a constituent (b) being an isocyanate prepolymer with ether and blocked urethane groups, wherein the amount of constituent (a) comprises from 29 to 52 percent by weight of the total weight of constituents (a) and (b), and the amount of constituent (b) comprises from 48 to 71 percent by weight of the total weight of constituents (a) and (b), and a second component comprising a mixture of constituent (c) being a suitable amine hardener, constituent (d) being a tertiary amine as a primary accelerator, and constituent (e) being a mercaptan terminated polymer such as Capcure 3-800 as secondary accelerator, wherein the amount of constituent (c) comprises from 0.3 to 47 percent by weight of the total weight of constituent (a) and (b), the amount of constituent (d) comprises 1 to 27 percent by weight of the total weight of the constituents (a) and (b), and the amount of constituent (e) comprises 21 to 328 percent by weight of the total weight of constituents (c) and (d). The first component and the second component are blended together in a ratio of approximately 2 to 1 to form the adhesive or sealing composition.

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Krugersdorp, South Africa

Kimleigh George Pratley