| 摘要 |
Therefore broadly in accordance with the invention there is provided a sheet like substrate comprising a substantially non-polar material having coated onto at least one side thereon an anchor coating to aid subsequent coating thereon of a polar coating and/or layer, characterised in that the anchor coating comprises (a) a polymer comprising an optionally substituted alpha, beta carboxylic acid optionally of high acid value preferably the polymer having a low T<SUB>g</SUB>; (b) a polymer comprising an optionally unsubstituted alpha, beta carboxylic acid optionally of low acid value preferably the polymer having a high T<SUB>g</SUB>; (c) a cross-linker, preferably added after a period of time to a mixture of polymers (a) and (b) to cross-link the resultant coating composition and increase the T<SUB>g </SUB>thereof. Preferably films of the invention provide directly on the anchor coating; a further polar coating or layer. Preferably (a) is a low acid imminated acrylic polymer (such as that available from Avecia under the trade name XK90); (b) is an alkyl methacrylate polymer of low acid functionally such as that available commercially from Avecia under the trade name Ucrecyl H; and (c) is an arizidine cross-linker such as the trimethyloltris(N(methylaziridinyl))propionate available from Avecia under the trade name CX100).
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