| 摘要 |
<p>A vinyl halide, such as vinyl chloride, polymer or copolymer containing a major proportion of a vinyl halide and a minor amount of e.g. vinyl acetate, is dissolved in a volatile solvent, a permanently fusible acid-catalysed phenol-aldehyde resin added and this solution is then mixed with a solution of a thermosetting soluble-stage alkali-catalysed phenol-aldehyde resin in a volatile solvent. The proportion of thermosetting resin is from 2 to 40 per cent of the total resin solids, and the amount of the acid catalysed resin is at least 1/10 of the thermosetting, less than 10 per cent of the total resins and less than the amount of thermosetting resin. A generic formula for the vinyl resins is given as [CH2=CA.X]n, where A is for the major part hydrogen but may be for a minor part a lower alkyl group, and X is for the major part a halogen but may be for a minor part a monocarboxylic acyloxyl, an alkyl carboxylate, phenyl or a substituted phenyl radical, n being the degree of polymerization. The phenol used in preparing the phenol-aldehyde resins may be phenol, cresol, or alkyl-, aryl-, carboxyl-, hydroxyl- or halogen-substituted phenols, and aldehydes specified are formaldehyde, paraformaldehyde, hexamethylene tetramine and acetaldehyde. Solvents specified are cyclohexanone, 2-nitroparaffin, mesityl oxide, diisobutyl ketone, methyl n-amyl ketone, used in conjunction with diluents such as xylol, high-flash naphtha or hydrogenated naphtha, and methyl isobutyl ketone along, or with isophorone, or with toluol. Optional additions are propylene oxide, aluminium powder, yellow lake pigment, and Resin oil Brown Y dye. The compositions may be applied to metal surfaces and baked to yield stratified coatings. Specification 606,889 is referred to.</p> |
