Koppers Company, Inc.

Kopper Company, Inc.

Vincent J Wojtyna

John D Carlson

James P Colton

Edward W Kifer

The present invention is directed to aqueous phenol formaldehyde resoles that have particular application in manufacturing phenolic foam insulation. The resoles are essentially phenol formaldehyde condensation polymers having molar ratios of formaldehyde to phenol of from about 1.7:1 to 2.3:1, preferably from 1.75:1 to 2.25:1 and most preferably about 2:1. The resoles have a weight average molecular weight greater than 800 and preferably from 950-1500. The resoles also have a number average molecular weight greater than 350 and preferably from about 400 to about 600 and a dispersivity greater than about 1.7, preferably from 1.8 to 2.6. Phenol formaldehyde resoles having these characteristics are processable into phenolic foams having a low k value and having other physical characteristics which make the phenolic foam especially useful as an insulation material. The present invention is also directed to foamable phenolic resole compositions prepared from the phenolic resoles and phenolic foams prepared from the compositions.

Phenol formaldehyde resoles for making phenolic foam

The present invention is directed to a method of preparing a phenolic foam that has cell walls which are substantially free of perforations. The method comprises using certain anhydrous aryl sulfonic acids as the foaming and curing catalysts. The useful anhydrous aryl sulfonic acids are those which have a pKa of less than about 2.0 and which change the compatibility of the phenolic resole with water. The preferred anhydrous aryl sulfonic acid is a combination of toluene sulfonic acid and xylene sulfonic acid. The invention is also directed to a phenolic foam having cell walls which are substantially free of perforations and to foamable phenolic resole compositions for preparing the phenolic foam.

Method for preparing phenolic foams using anhydrous aryl sulfonic acid

Closed-cell phenolic foam having a uniform cell structure in which the cell walls are substantially free of both ruptures and perforations is disclosed. The phenolic foam has initial k values of less than 0.15 with substantially no increase of k value over time and good density and compressive strengths. The phenolic foam is prepared by foaming and curing a foamable phenolic resole composition containing an aqueous phenol formaldehyde resole, surfactant, fluorocarbon blowing agent, and optionally other additives with an acid foaming and curing catalyst in a substantially closed mold which exerts a restraining pressure on the foaming composition in excess of ambient atmosphericpressure of greater than about 3 pounds per square inch. The aqueous phenol formaldehyde resole is essentially a phenol formaldehyde condensation polymer having a molar ratio of formaldehyde to phenol of from about 1.7:1 to 2.3:1, preferably from 1.75:1 to 2.25:1 and most preferably about 2:1. The resole has a weight average molecular weight greater than 800 and preferably from 950-1500. The resole also has a number average molecular weight greater than about 350 and preferably from about 400 to about 600 and a dispersivity greater than about 1.7, preferably from 1.8 to 2.6. The acid foaming and curing catalyst is an anhydrous aryl sulfonic acid having a pKa less than about 2.0 and which changes the compatibility of the phenolic resole with water. The preferred anhydrous aryl sulfonic acid is a combination of toluene sulfonic acid and xylene sulfonic acid.

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Lyndora, PA, United States of America

Vincent J Wojtyna