US 5,470,924 AGranted

Phenol formaldehyde resins

OwnerBarry W. Ryaninventor

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Abstract

A process for forming a phenol formaldehyde resin including the steps of: (i) forming a first additive including a glycol and an aromatic dicaborxylic acid; (ii) adding said first additive as well as an alpha hydroxy acid to a first resin component comprising resin precursors including phenol, formaldehyde, an acid catalyst or a base catalyst after said precursors have reacted for 40-55 minutes and/or when water has separated from said precursors; (iii) isolating or storing said first resin component which is maintained in a non cured state by the addition of said first additive; (iv) forming a second additive including zinc chloride, an alpha hydroxy acid, para toluene sulphonic acid, sulphuric or hydrochloric acid and a non aqueous solvent; (v) adding said second additive to a second resin component which includes resin precursors phenol, formaldehyde, methanol and an aliphatic dicarboxylic acid after said precursors have reacted for 20-30 minutes; (vi) combining said first resin component and said second resin component and subsequently allowing a mixture formed thereby to cure. There is also included both the first resin component and the second resin component whereby in each component the mole ratio between formaldehyde and phenol is greater than unity.

Claims27

Dependent claims

A process for forming a phenol formaldehyde resin consisting essentially of the steps of:

(i) forming a first additive by mixing a glycol with an aromatic dicarboxylic acid or anhydride of said acid in a ratio of from 2:1 to 5:1;
(ii) forming a first resin component by reacting phenol with excess formaldehyde in the presence of non-aqueous solvent and a catalyst for about 40-55 minutes until water has separated from the reactants forming a two phase solution having immiscible layers, and then adding said first additive as well as an alpha hydroxy acid;
(iii) isolating or storing said first resin component with said first additive formed in (ii), said first resin component being maintained in a non-cured state by the addition of said first additive;
(iv) forming a second resin additive by mixing a solution consisting essentially of zinc chloride, glycerol, an alpha hydroxy acid, p-toluene sulphonic acid, sulphuric or hydrochloric acid, and a non-aqueous solvent;
(v) forming a second resin component by reacting phenol with excess formaldehyde in the presence of methanol and an aliphatic dicarboxylic acid catalyst for about 20-30 minutes, and then adding said second additive;
(vi) combining the components formed in (ii) and (v) in a ratio of from about 2:1 to 4:1 to form a phenol formaldehyde resin and then allowing the mixture thus formed to cure.

3 more elements

Dependencies are inferred from the claim text.