Rapid setting polyurethanes from diols and polyfunctional isocyanates
AssigneeThe Dow Chemical Company
InventorFranciszek Olstowski
Life of this patent
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Abstract
Mixtures comprising a low molecular weight diol, a liquid modifier compound having a boiling point above about 150.degree. C, such as a fatty acid or fatty oil, a polyisocyanate having a functionality of at least about 2.5 and an organotin catalyst instantly set, after a brief induction period, to a solid, dense, rigid polymeric product which can be demolded within a period of from less than 1 minute to about 5 minutes.
Claims16
A rigid, non-cellular composition having a density of at least about 1 gram/cc which is demoldable, without the application of an external source of heat, within about 5 minutes after admixture of the components of the composition which is the reaction product of a polyurethane-forming composition comprising
- A. a dihydroxyl-containing compound having a hydroxyl equivalent weight of less than about 250;
- B. an organic polyisocyanate having an NCO functionality of at least about 2.5;
- C. a liquid modifier compound having a boiling point of at least about 150.degree. C or mixture of such compounds and which moderates the reaction exotherm between components (A), (B), and (D) without substantial reaction therewith selected from the group consisting of fatty oils, fatty acids and mixtures thereof;
- and
- D. and organotin catalyst;
- wherein components (A) and (B) are present in quantities such that the NCO:OH ratio is from about 0.8:1 to about 1.5:1, component (C) is present in quantities of from about 10 to about 50 percent by weight of the combined weights of components (A), (B) and (C);
- and component (D) is present in quantities of from about 0.02 to about 5.0 percent by weight of the combined weight of components (A), (B) and (C).
A process for producing solid, rigid, polyurethane articles having a density of at least 1 g/cc, a percent elongation of less than 100, and which can be demolded within a period of about 5 minutes without the addition of an external source of heat which process comprises:
- 1. admixing the components of a composition comprising
- A. a dihydroxyl-containing compound having a hydroxyl equivalent weight of less than about 250;
- B. an organic polyisocyanate having an NCO functionality of at least about 2.5;
- C. a liquid modifier compound having a boiling point of at least about 150.degree. C or mixture of such compounds and which moderates the reaction exotherm between components (A), (B) and (D) without substantial reaction therewith selected from the group consisting of fatty oils, fatty acids and mixtures thereof;
- and
- D. an organotin catalyst;
- wherein components (A) and (B) are present in quantities such that the NCO:OH ratio is from about 0.8:1 to about 1.5:1, component (C) is present in quantities of from about 10 to about 50 percent by weight of the combined weights of components (A), (B) and (C);
- and component (D) is present in quantities of from about 0.02 to about 5.0 percent by weight of the combined weight of components (A), (B) and (C);
- 2. placing the admixed composition into a suitable mold wherein said composition solidifies within less than about 5 minutes to a solid having the aforesaid density and elongation;
- and
- 3. subsequently demolding the resultant article from the mold.
Dependencies are inferred from the claim text.