초록 ▼

This invention relates to rigid closed-celled polyisocyanate-based foams exhibiting improved dimensional stability and a process for their preparation. In particular, it relates to foams containing within their cells, when initially prepared, a gas mixture comprising theoretically from about 5 to 70

This invention relates to rigid closed-celled polyisocyanate-based foams exhibiting improved dimensional stability and a process for their preparation. In particular, it relates to foams containing within their cells, when initially prepared, a gas mixture comprising theoretically from about 5 to 70 mole percent carbon dioxide and from about 40 to about 95 mole percent of an organic compound mixture. The organic compound mixture itself, comprises (a) from 40 to 95 mole percent of an organic compound having a boiling point greater than or equal to about 283K, and (b) from 5 to 60 mole percent of an organic compound having a boiling point equal to or less than about 266K. Halocarbons are the preferred organic compounds for components (a) and (b).

대표청구항 ▼

A process for preparing a rigid closed-celled polyisocyanate-based foam by reacting at least one organic polyisocyanate with at least one active hydrogen-containing compound in the presence of a blowing agent composition characterized in that the composition comprises: (a) from about 40 to about 95

A process for preparing a rigid closed-celled polyisocyanate-based foam by reacting at least one organic polyisocyanate with at least one active hydrogen-containing compound in the presence of a blowing agent composition characterized in that the composition comprises: (a) from about 40 to about 95 mole percent based on components (a) and (b) of at least one organic compound having a boiling point of at least about 283K, and (b) from about 5 to about 60 mole percent based on components (a) and (b) of at least one organic compound having a boiling point less than or equal to about 266K, and wherein the ratio of the said boiling point of a component (a) to a component (b) is from about 1.06:1 to about 1.20:1 and wherein the said composition is substantially free of any organic compound having a boiling point of at least 338K.