초록 ▼

Soft linear thermoplastic polyurethanes, which have low permanent set, high tear propagation resistance, and low blocking, and which are extrudable by blown film techniques, are prepared by reacting one mole of a hydroxyl terminated polyester having a molecular weight from about 1800 to about 3600,

Soft linear thermoplastic polyurethanes, which have low permanent set, high tear propagation resistance, and low blocking, and which are extrudable by blown film techniques, are prepared by reacting one mole of a hydroxyl terminated polyester having a molecular weight from about 1800 to about 3600, from about 0.5 to about 2.0 moles of an aromatic glycol chain extender, and an organic diioscyanate in molar quantities substantially equal to the sum of the molar quantities of polyester and chain extender. The polyester is a mixed polyester prepared by reacting at least two different aliphatic glycols with one or more organic dicarboxylic acids or at least one alaphatic glycol with two or more organic dicarboxylic acids. The aliphatic glycol may have from 2 to about 10 carbon atoms. The organic dicarboxylic acid may be either aliphatic or aromatic and may have from 2 to about 12 carbon atoms. The preferred chain extender is hydroquinone bis(beta-hydroxyethyl)ether. Polymers of this invention are useful as elastic tapes, and in particular as leg bands in diapers and adult incontinence garments. They may be used for other items of form-fitting apparel, such as ladies swim suits.

대표청구항 ▼

An essentially linear film forming thermoplastic polyurethane elastomer comprising the reaction product of: (a) a random mixed hydroxyl terminated polyester of the formula (I) [Figure] (I) said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of th

An essentially linear film forming thermoplastic polyurethane elastomer comprising the reaction product of: (a) a random mixed hydroxyl terminated polyester of the formula (I) [Figure] (I) said polyester having a molecular weight of about 1800 to about 3600 and having essentially the structure of the reaction product of at least two straight chain aliphatic glycols containing from 2 to about 10 carbon atoms; (b) an aromatic glycol chain extender of the formula (II) HO－Y－OH, aliphatic diol chain extenders other than small adventitious amounts not exceeding 0.75 percent of the weight of said polyester (a) being absent, and (c) an isocyanate of the formula (III) OCN－Z－NCO wherein (1) A is at least two alkylene radicals, oxydialkylene radicals or mixture thereof containing from 2 to about 10 carbon atoms, and B is an alkylene radical containing from 2 to about 10 carbon atoms or an arylene radical containing from 6 to about 12 carbon atoms or a mixture thereof, Y is a phenylenedialkylene or phenyleneoxyalkylene radical containing from about 8 to about 14 carbon atoms; and Z is a divalent organic radical; (2) The value of m is such that said polyester has a molecular weight from about 1800 to about 3600; (3) the molar ratio of said chain extender to said polyester is from about 0.75 to about 2; (4) the molar quantity of said isocyanate is substantially equal to the sum of the molar quantities of said polyester and said chain extender, and (5) said elastomer has a modulus at 100 percent elongation of 350 to 700 psi.