Wire enamel
AssigneeChemische Fabrik Dr. Wiedeking
InventorKlaus Ohm
Life of this patent
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Abstract
Polyester-polyimide resins having a hydroxyl value of 150 to 600 and containing repeating units derived from tris-(2-hydroxyethyl) isocyanurate or tris-(2-carboxyethyl) isocyanurate are known valuable film-forming agents in wire enamels. Enamels of low viscosity at high solids content can be prepared by dissolving the resins in solvent systems free from phenols and containing at least 30% (wt.) diacetylacetone, monoalkylesters of ethylene glycol, diethylene glycol and the like, and lower alkanoic acid esters of the ethers, and these solvent components are less irritating and partly less toxic than solvents employed heretofore.
Claims9
In a wire enamel consisting essentially of a polyesterpolyimide resin and a solvent system containing said resin as a solute, the resin having a hydroxyl value of 150 to 600, and at least 20% by weight of the alcohol component of said resin consisting of tris-(2-hydroxyethyl) isocyanurate, the improvement in the solvent system which comprises:
- (a) 30% to 100% of the weight of said solvent system consisting of at least one member of the group consisting of diacetone alcohol, monoalkyl ethers of the formula C.sub.n H.sub.2n+1 --(O--CH.sub.2 --CH.sub.2).sub.m --OH, and alkanoic acid esters of said ethers,
- (1) in said formula, n and m being integers, n being 1 to 4, and m being 1 or 2, and
- (2) said alkanoic acid having a carbon chain of not more than four members;
- and
- (b) the remainder of said solvent system essentially consisting of compounds free from phenolic hydroxyl groups when said at least one member is less than 100%.
Dependencies are inferred from the claim text.