Abstract This invention pertains to the manufacture of foams from phenolic resins and to the foams so produced. Such foams are made by mixing a blowing agent with the resin in a soft or fluid state, adding a hardening catalyst which produces an exothermic reaction of sufficient intensity to vaporize the blowing agent and form the foam, and hardening the foam. In such processes a strong acid is usually employed to generate the exothermic reaction but its action is accompanied by undesirable side effects, e.g. during the use of the foams as insulators for a metal object the residual acid in the resin may produce corrosion. To reduce that objection the resin has been processed to remove or neutralize the acid, or both, the attempt being to eliminate the large part of the acid and neutralize the residue. Such processing is difficult and imperfect. According to the invention Resorcinol is included in the composition of the phenolic resin which is to be foamed by acid catalysts. The presence of the Resorcinol is productive of several advantages including improvement of electrical properties, color stability and reduction of corrosive tendencies.
A METHOD OF MAKING A NON-CORROSIVE ACID-CATALYZED NON-FLAMMABLE SELF-EXTINGUISHING PHENOL-FORMALDEHYDE RESIN WHICH COMPRISES MIXING A LIQUID PHENOL-FORMALDEHYDE RESIN CONTAINING A RATIO OF FORMALDEHYDE TO PHENOL OF AT LEAST TWO, WITH FROM 5 TO 8 PERCENT BY WEIGHT BASED ON THE RESIN OF RESORCINOL, AN ORGANIC LIQUID BLOWING AGENT HAVING A BOILING POINT FROM ABOUT 22* TO 80*C AND ABOUT 10 PERCET BY WEIGHT OF DICYANDIAIDE-FORMALDEHYDE AND ABOUT 10 PERCENT BY WEIGHT OF A 35 PERCENT AQUEOUS SOLUTION OF HCL.
Claim 2
Independent Claim
79 words
A METHOD OF MAKING A NON-CORROSIVE ACID-CATALYZED NON-FLAMMABLE SELF-EXTINGUISHING PHENOL-FORMALDEHYDE RESIN WHICH COMPRISES MIXING A LIQUID PHENOL-FORMALDEHYDE RESIN CONTAINING A RATIO OF FORMALDEHYDE TO PHENOL OF AT LEAST TWO, WITH FROM 5 TO 8 PERCENT BY WEIGHT BASED ON THE RESIN OF RESORCINOL, AN ORGANIC LIQUID BLOWING AGENT HAVING A BOILING POINT FROM ABOUT 22* TO 80*C AND ABOUT 10 PERCET BY WEIGHT OF DICYANDIAIDE-FORMALDEHYDE AND ABOUT 10 PERCENT BY WEIGHT OF A 35 PERCENT AQUEOUS SOLUTION OF HCL.
Claim 3
Independent Claim
106 words
A method of making a non-corrosive acid-catalyzed non-flammable self-extinguishing phenol-formaldehyde resin which comprises mixing a liquid phenol formaldehyde resin containing a ratio of aldehyde to phenol of at least two with 10 % by weight of resorcinol in 80 percent aqueous solution, 1.5 percent by weight of a silicone oil, said oil being a hydrosoluble silicone-glycol copolymer, 5 percent by weight of a mineral filler, 5 percent by weight of an organic liquid blowing agent having a boiling point between 22*C. and 80*C., 10 percent by weight of dicyandiamide-formaldehyde in 67 percent aqueous solution and 10 percent by weight of 35 percent aqueous solution of HC1.
Claim 4
Independent Claim
106 words
A method of making a non-corrosive acid-catalyzed non-flammable self-extinguishing phenol-formaldehyde resin which comprises mixing a liquid phenol formaldehyde resin containing a ratio of aldehyde to phenol of at least two with 10 % by weight of resorcinol in 80 percent aqueous solution, 1.5 percent by weight of a silicone oil, said oil being a hydrosoluble silicone-glycol copolymer, 5 percent by weight of a mineral filler, 5 percent by weight of an organic liquid blowing agent having a boiling point between 22*C. and 80*C., 10 percent by weight of dicyandiamide-formaldehyde in 67 percent aqueous solution and 10 percent by weight of 35 percent aqueous solution of HC1.