Castable thermosetting polyurethane polymer having improved heat stability
First Claim
1. A thermosetting castable polyurethane polymer having improved heat-stability characteristics, comprising:
- (A) a polymeric methylene diisocyanate having a functionality of at least about 2;
(B) a polyol having a molecular weight between about 300 and about 900 and an OH-functionality between about 3.0 and about 6.0;
(C) a polyether diol or triol having a molecular weight between about 500 and about 4000 and an OH-functionality between about 1.8 and about 3.2;
(D) a glycol selected from dipropylene glycol and diethylene glycol having a molecular weight between about 100 and 200 and an OH-functionality between about 1.8 and about 2.2;
said constituent diols and polyols being in the proportion of about 35 through about 45 parts by weight of (B), about 35 through about 45 parts by weight of (C), and about 12 through about 20 parts by weight of (D), per 100 parts by weight of all diol and polyol components;
(E) an effective polyurethane-catalyzing amount of a urethane catalyst; and
(F) the isocyanate component (A) and combined diol and polyol components (B), (C), and (D), being in proportions so as to provide an NCO/OH ratio to at least about 1;
1.
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Accused Products
Abstract
A castable thermosetting polyurethane polymer, having improved heat-stability characteristics, comprising (A) a polymeric methylene diisocyanate, (B) a propyleneoxide-extended polyol which is preferably a sugar-based polyol, (C) a polyether diol or triol, and (D) dipropylene glycol or diethylene glycol, in amounts respectively between about 35-45 parts by weight, 35-45 parts by weight, and 12-20 parts by weight, per 100 parts by weight of total diol and triol (resin) components, providing an NCO/OH ratio between about 1:1 and about 1.2:1, an effective polyurethane-catalyzing amount of (E) a urethane catalyst, and optionally comprising an effective amount of a drying agent, is disclosed. The cast polyurethane polymer of the invention withstands temperatures of 450° F. (232° C.) for 20 minutes without visual polymer degradation, whereas most other castable polyurethane systems degrade between 350° F. and 375° F., as a result of which heat-stability the polymer of the present invention is especially suitable for post finishing which involves the employment of higher temperatures, such as painting with thermosetting coatings, powder coating, and anodizing.
42 Citations
22 Claims
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1. A thermosetting castable polyurethane polymer having improved heat-stability characteristics, comprising:
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(A) a polymeric methylene diisocyanate having a functionality of at least about 2; (B) a polyol having a molecular weight between about 300 and about 900 and an OH-functionality between about 3.0 and about 6.0; (C) a polyether diol or triol having a molecular weight between about 500 and about 4000 and an OH-functionality between about 1.8 and about 3.2; (D) a glycol selected from dipropylene glycol and diethylene glycol having a molecular weight between about 100 and 200 and an OH-functionality between about 1.8 and about 2.2; said constituent diols and polyols being in the proportion of about 35 through about 45 parts by weight of (B), about 35 through about 45 parts by weight of (C), and about 12 through about 20 parts by weight of (D), per 100 parts by weight of all diol and polyol components; (E) an effective polyurethane-catalyzing amount of a urethane catalyst; and (F) the isocyanate component (A) and combined diol and polyol components (B), (C), and (D), being in proportions so as to provide an NCO/OH ratio to at least about 1;
1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification