In a method for producing resol type phenol resin foams by using starting material for the foams prepared by blending a resol type phenol resin, a blowing agent and a catalyst, a low molecular weight resol type phenol resin with the number average molecular weight of less than 200 and a high molecular weight resol type phenol resin with the number average molecular weight of greater than 200 are mixed at a weight ratio of from 5/95 to 80/20 and used as the resol type phenol resin. The resol type phenol resin foams are excellent in adhesion, fire-proofness capable of foaming cure in a short time and useful for sprayed-in-place foaming, etc. The phenol resin foams produced by the invention are capable of integral foaming with rigid urethane resin foam layer into foamed laminates of excellent thermal insulation, fire-proofness, etc.
A rigid polyurethane foam obtained by foaming a special polyol component and an isocyanate component using only water as a blowing agent has balanced excellent properties including a remarkably low density and a low thermal conductivity and is suitable for use as a heat insulator, particularly in a refrigerator.
Process for preparing a flexible polyurethane foam by reacting an isocyanate-containing prepolymer and an isocyanate-reactive composition comprising water in the presence of a dialkyl imidazole catalyst.
A regulating device for screw-type compressors, which contain a compressor dement (1), an electrical motor (2) to drive the compressor element (1), a minimum pressure valve (4) which is mounted on the outlet (5) of the compressor element (1) and a vessel (6) which is mounted between the compressor element (1) and the minimum pressure valve (4), includes a controller which causes the motor (2) to turn at a frequency-regulated rotational speed at an almost constant pressure in the vessel (6), and a non-return valve (12) which is mounted on the inlet (10) of the compressor element (1) to aid in starting and stopping the motor.
An improved durable, low density, high build polyurethane coating is disclosed, as well as its method of manufacture. A slow reacting polyisocyanate is combined with a polyol so as to form a uniform mixture with an extremely long pot life. The low viscosity uniform mixture can then be sprayed onto a substrate using a conventional spray gun. A polyurethane catalyst is introduced after formation of the uniform mixture, preferably via a second spray nozzle so that catalyst is externally mixed into the polyisocyanate/polyol spray stream. This is a 100%, or near 100%, solids system so that there is very low volatile organic compound emissions.
An improved durable, low density, high build polyurethane coating is disclosed, as well as its method of manufacture. A slow reacting polyisocyanate is combined with a polyol so as to form a uniform mixture with an extremely long pot life. The low viscosity uniform mixture can then be sprayed onto a substrate using a conventional spray gun. A polyurethane catalyst is introduced after formation of the uniform mixture, preferably via a second spray nozzle so that catalyst is externally mixed into the polyisocyanate/polyol spray stream. This is a 100%, or near 100%, solids system so that there is very low volatile organic compound emissions.
