Process for the manufacture of unsaturated polyester resins
AssigneeHercofina
InventorsWilliam H. Millick, 3rd, Norman R. Newburg
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Abstract
Disclosed is a process for producing styrene-soluble unsaturated polyester resins from DMT process residue. In a preferred embodiment of the process, DMT process residue is transesterified with propylene glycol until a hydroxyl-terminated ester product having a methoxyl content within a specified range is formed and then the resulting ester product is esterified with maleic anhydride.
Claims5
A process for producing styrene-soluble unsaturated polyester resins from DMT process residue having a methoxyl content within the range of 8 to 25%, which process comprises forming from said residue a hydroxyl-terminated ester product having a methoxyl content which is inversely related to the methoxyl content of said residue and is within the range defined by equations
- Y=3.0-0.10X and Y=4.0+0.25X
- where Y is the methoxyl content of said ester product and X is the methoxyl content of said residue and is within the range of 8 to 25 by
- (a) transesterifying said residue with an excess of at least one dihydric alcohol until the methoxyl content is within the above defined range, or
- (b) transesterifying said residue with an excess of at least one dihydric alcohol until the methoxyl content is below the value defined by the equation Y=3.0-0.10X and adding thereto a sufficient quantity of said residue to adjust the methoxyl content of the product to a value within the above defined range, and
- reacting said ester product with an unsaturated dicarboxylic acid or its anhydride to form said unsaturated polyester resin.
Dependencies are inferred from the claim text.