Abstract: Disclosed is a process for preparing an open-celled rigid polyurethane foam by reacting a polyisocyanate with a polyol in the presence of a blowing agent, usually water, and a cell opening agent. The cell opening agent comprises a combination of a polyoxyalkylene polysiloxane having a cloud point of 65.degree. C. or less, and a second substance that has a critical surface free energy of less than about 23 mJ/m.sup.2. Highly preferred as second substance is fine particulate poly(tetrafluoroethylene) polymer.

Abstract: Disclosed is a process for preparing an open-celled rigid polyurethane foam by reacting a polyisocyanate with a polyol in the presence of a blowing agent, usually water, and a cell opening agent. The cell opening agent comprises a combination of a polyoxyalkylene polysiloxane having a cloud point of 65.degree. C. or less, and a second substance that has a critical surface free energy of less than about 23 mJ/m.sup.2. Highly preferred as second substance is fine particulate poly(tetrafluoroethylene) polymer.

Abstract: This disclosure relates to polyisocyanate-based foams, particularly to polyurethane or polyurethane-polyisocyanurate foam prepared in the presence of a certain blowing agent. The blowing agent, based on total amounts of a) and b), consists of: (a) from about 5 to about 80 mole percent of a C.sub.5-6 alicyclic alkane or mixtures of such; and (b) from about 95 to about 20 mole percent of a mixture of isopentane and n-pentane present in a mole ratio of from about 80:20 to about 20:80.

Abstract: This disclosure relates to polyisocyanate-based foams, particularly to polyurethane or polyurethanepolyisocyanurate foam prepared in the presence of a certain blowing agent. The blowing agent, based on total amounts of a) and b), consists of: (a) from about 5 to about 80 mole percent of a C.sub.5-6 alicyclic alkane or mixtures of such; and (b) from about 95 to about 20 mole percent of a mixture of isopentane and n-pentane present in a mole ratio of from about 80:20 to about 20:80.

Abstract: Polyisocyanate-based foams having a uniformly fine cell size are prepared by reacting a polyisocyanate with an isocyanate-reactive compound in the presence of a blowing agent mixture comprising a hydrocarbon component which has four or more carbon atoms and a polyfluorocarbon component which has a boiling point of from about 283 K. to about 393 K. at 760 mm Hg and wherein the boiling point:molecular weight ratio of said polyfluorocarbon component is less than or equal to 1.7. The hydrocarbon component is present in from about 5 to about 95 mole percent and the polyfluorocarbon in from about 95 to about 5 mole percent based on total amounts of hydrocarbon and polyfluorocarbon.

Abstract: A process for preparing a cellular polymer containing perforated cell windows in the presence of a perforating agent being a substance that has a critical surface free energy of less than about 23 mJ/m.sup.2 is disclosed. The cellular polymers obtained according to this invention have a fine cell structure and show enhanced dimensional and thermal insulation stability. The invention also relates to rigid polyurethane foam prepared in the presence of, for example, particulate poly(tetrafluoroethylene) or a liquid polyfluoro- or perfluorocarbon, with a boiling point of at least 130.degree. C., as perforating agent.

Abstract: A process for preparing a cellular polymer containing perforated cell windows in the presence of a perforating agent being a substance that has a critical surface free energy of less than about 23 mJ/m.sup.2 is disclosed. The cellular polymers obtained according to this invention have a fine cell structure and show enhanced dimensional and thermal insulation stability. The invention also relates to rigid polyurethane foam prepared in the presence of, for example, particulate poly(tetrafluoroethylene) or a liquid polyfluoro- or perfluorocarbon, with a boiling point of at least 130.degree. C., as perforating agent.

Abstract: Closed-cell polyisocyanate-based foams are prepared using a blowing agent mixture containing an organic compound having a boiling point in excess of 65.degree. C. in conjunction with another organic compound having a boiling point below about 40.degree. C.

Abstract: This invention relates to the use of a C.sub.2-6 polyfluorocarbon compound containing no chlorine or bromine atoms as physical blowing agent in the preparation of rigid, closed-cell, polymer foams. Use of such blowing agents, especially 1,1,1,2-tetrafluoroethane (R-134a), in the preparation of polyurethane or polyisocyanurate foams provided for products in which the loss in thermal insulation performance with time compared to products prepared in absence of such blowing agents is reduced.

Abstract: This invention relates to a process for preparing a rigid, closed-celled polyisocyanate-based foam in the presence of a blowing agent composition. The blowing agent composition comprises one or more organic compounds, particularly halocarbons, having a boiling point of less than or equal to 272K at atmospheric pressure, and further is substantially free of organic compounds having a boiling point of 273K or greater. Preferred halocarbons are chlorofluoroethanes and fluoroethanes.

Abstract: Rigid closed-cell polyisocyanate-based foams are prepared by the reaction of polyisocyanate with a polyol composition having an average hydroxyl number of about 100 to about 500 and comprising at least one polyether polyol containing four or more active hydrogens and having a hydroxyl number of from about 50 to about 500. The blowing of the foam is essentially with carbon dioxide generated from the reaction of water with polyisocyanate so as to provide foams of the desired density containing at least 40 mole percent carbon dioxide in their cells.