Resole melamine dispersions as adhesives
AssigneeBorden, Inc.
InventorWayne R. Walisser
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Abstract
The invention relates to a composition consisting of a melamine solid suspended or dispersed in a resole resin. The method of the invention favors the intermolecular condensation polymerization reaction between phenol and melamine, rather than homopolymerization between phenol molecules or between melamine molecules. This invention reduces formaldehyde emissions by favoring a reaction whose by-product is water rather than formaldehyde. The compositions are useful for bonding glass fiber mats used for thermal and acoustical insulation.
Claims22
A water soluble, A-stage, unreacted, uncured but curable composition consisting of:
- (a) an alkaline phenolic resole resin having a formaldehyde to phenol mole ratio of from 0.5:1 to 3.5:1 and a base catalyst to phenol mole ratio of from 0.01:1 to 1:1;
- (b) melamine crystal dispersed in the resole resin, wherein the melamine crystal to phenol mole ratio is from 0.01:1 to 1.0:1.0;
- and
- (c) an acid selected from the group consisting of oxalic acid, sulfamic acid, nitric acid, and methane sulfonic acid, in an amount sufficient to catalyze the polymerization reaction of said resin with the melamine crystal upon subsequent exposure to elevated temperatures, neutralize the base and drop the pH of the dispersion to a level of from 2.5 to about 5.5;
- and wherein the dispersion produced is a water soluble, curable, A-stage composition.
A method of preparing a water-soluble curable composition consisting of the steps of:
- (a) preparing an alkaline resole resin composition by combining formaldehyde and phenol at a formaldehyde to phenol mole ratio of from about 0.5:1 to 3.5:1 in the presence of a basic catalyst, wherein the catalyst to phenol mole ratio is from about 0.01:1 to 1:1;
- (b) dispersing in said resole resin a quantity of melamine crystal, wherein the melamine crystal to phenol mole ratio is from 0.01:1 to 1:1;
- and
- (c) adding to the dispersion of step (b) an acid selected from the group consisting of oxalic acid, sulfamic acid, nitric acid, and methane sulfonic acid in an amount sufficient to drop the pH to a level of from 2.5 to 5.5, wherein the temperature is not sufficient to dissolve the melamine or to initiate any polymerization between the melamine and the resole.
Dependencies are inferred from the claim text.