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AssigneeEastman Kodak Company
InventorsWilliam L. Edmonson, Anthony W. McCollum
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The present invention provides a process for the preparation of low molecular weight polyesters directly from hydroxypivaldehyde. The process comprises reacting dry hydroxypivaldehyde with a diester, a multifunctional ester, a diacid, a polyester, or a mixture thereof at a temperature of about 100.degree. C. to 230.degree. C. in the presence of a transesterification catalyst. Optionally, modifying glycols, triols, or polyols may also be added. Suitable catalysts include tetraisopropyl titanate, dibutyltin oxide, lithium hydroxide, and lithium alkoxide, with tetraisopropyl titanate being especially preferred. The reaction is preferably accomplished in two stages by heating the reaction mixture to about 130.degree. C. for about three hours and subsequently heating the reaction mixture to about 190.degree.-230.degree. C. until the reaction is essentially complete. In an especially preferred embodiment, the low molecular weight polyesters are produced by the reaction of hydroxypivaldehyde with a diester such as dimethyl adipate, dimethyl cyclohexane-1,4-dicarboxylate, and dimethyl terephthalate. The low molecular weight polyester product typically exhibits a molecular weight of about 400-2000 and a hydroxyl number of about 100-300.
A process for the preparation of low molecular weight polyesters which comprises reacting dry hydroxypivaldehyde with a diester, a diacid, a polyester, or a mixture thereof at a temperature of about 100.degree. C. to about 230.degree. C. in the presence of a transesterification catalyst.
A process for the preparation of low molecular weight polyesters which comprises reacting dry hydroxypivaldehyde with a lower alkyl diester of a dicarboxylic acid, the lower alkyl groups containing 1 to 6 carbon atoms, in a molar ratio of dry hydroxypivaldehyde:diester of about 2:1 to 8:1 at a temperature of about 100.degree. to 230.degree. C. in the presence of about 0.1% by weight, based upon the weight of dry hydroxypivaldehyde, of a transesterification catalyst selected from the group consisting of tetraisopropyl titanate, dibutyltin oxide, lithium hydroxide, and lithium alkoxide.
A process for the preparation of low molecular weight polyesters which comprises reacting about 10 to 60 percent by weight based upon the total weight of the reaction of dry hydroxypivaldehyde with a polyester reactant selected from the group consisting of the polymeric products of the reaction of ethylene glycol, butylene glycol, cyclohexanedimethanol, or mixtures thereof with terephthalic acid, isophthalic acid, orthophthalic acid, or mixtures thereof, said dry hydroxypivaldehyde being reacted with said polyester reactant at a temperature of about 100.degree. to 230.degree. C. in the presence of about 0.1% by weight, based upon the weight of dry hydroxypivaldehyde, of a transesterification catalyst selected from the group consisting of tetraisopropyl titanate, dibutyltin oxide, lithium hydroxide, and lithium alkoxide.
Dependencies are inferred from the claim text.