Abstract: Powder coating compositions suitable for use in the manufacture of laser-engraved printing rollers, comprise(a) a difunctional epoxy resin prepared from a bisphenol,(b) an epoxy resin having an epoxide functionality greater than 2,(c) a diaminodiphenylsulphone as hardener for the mixture of resins (a) and (b), and(d) an imidazole as curing accelerator.These compositions, when applied to a metal base member, fused, and cured, provide a surface that is easily engravable yet has excellent resistance to chemical attack and physical wear.Typical difunctional epoxy resins (a) are 2,2-bis(4-glycidyloxyphenyl)propane advanced with bisphenol A, while typical epoxy resins that may be used as (b) include polyglycidyl ethers of phenol-formaldehyde novolaks. The hardener (c) my be, for example, 3,3'- and 4,4'-diaminodiphenylsulphones and the imidazole accelerator (d) may be 2-methylimidazole or benzimidazole.

Abstract: Powder coating compositions comprise an epoxide resin and a carboxylic acid of formula ##STR1## where R.sup.1 represents a phenylene or naphthylene group or a group comprising 2 or 3 phenylene radicals linked by one or two carbon-carbon bonds, ether oxygen atoms, sulfur atoms, or sulfonyl, sulfoxide, carbonyl or alkylene groups,R.sup.2 represents a saturated alkyl group, a benzenoid group or an aralkyl group, andboth n are the same and represent zero or 1.