Rigid thermoplastic plyurethane comprising units of butane diol and a polyethylene glycol
AssigneeThe Dow Chemical Company
InventorSteven R. Oriani
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Abstract
The present invention is a rigid thermoplastic polyurethane (RTPU) comprising units of butane diol (BDO) and a polyethylene glycol (PEG) of the type HO--(CH.sub.2 CH.sub.2 O).sub.n --H, where n is an integer from 2 to 6. The RTPU of the present invention addresses a problem in the art by providing a potentially lower-cost alternative to an RTPU prepared from hexane diol, and further providing an RTPU that can be customized to a desired toughness, T.sub.g, yield strength, and transparency. The RTPUs that are prepared from certain mole ratios of BDO and the PEG exhibit a surprisingly high degree of toughness manifested by increased tensile elongation to break.
Claims19
A rigid thermoplastic polyurethane comprising:
- a) units of a diisocyanate;
- b) units of a polyethylene glycol having the structure HO--(CH.sub.2 CH.sub.2 O).sub.n --H, where n is an integer from 2 to 6;
- c) units of butane diol;
- and d) not more than 25 weight percent of units of a high molecular weight diol based on the total weight of the rigid thermoplastic polyurethane, the rigid thermoplastic polyurethane being further characterized by having a T.sub.g of at least 50.degree. C., with the proviso that when the polyethylene glycol is triethylene glycol, at least one of the following limitations apply:
- a) the mole-to-mole ratio of the units of the triethylene glycol to the units of the butane diol is from 25:75 to 90:10:
- b) the rigid thermoplastic polyurethane comprises not more than 1.9 weight percent of units of the high molecular weight diol;
- or c) the thermoplastic polyurethane is optically transparent.
A rigid thermoplastic polyurethane comprising:
- a) units of a diisocyanate;
- b) units of triethylene glycol;
- c) units of butane did;
- and d) not more than 1.9 weight percent of units of a high molecular weight diol based on the total weight of the rigid thermoplastic polyurethane, the rigid thermoplastic polyurethane being further characterized by having a T.sub.g of at least 50.degree. C.
A rigid thermoplastic polyurethane comprising:
- a) units of a diisocyanate;
- b) units of diethylene glycol;
- c) units of butane diol;
- and d) not more than 25 weight percent of units of a high molecular weight diol based on the total weight of the rigid thermoplastic polyurethane, the rigid thermoplastic polyurethane being further characterized by having a T.sub.g of at least 50.degree. C.
Dependencies are inferred from the claim text.