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US 5,182,357 AGranted
Storage stable 100% solids high ortho phenol formaldehyde hot melt adhesives
AssigneeDAP Inc.
InventorGary L. Linden
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Abstract
One hundred percent thermosetting phenol/formaldehyde (P/F) resin and method of preparation thereof are disclosed. The resin comprises a molar ratio of F/P of about 1.2-1.7, has a softening point of about 80.degree. C. and cures at temperature of about 140.degree.-160.degree. C. The method comprises heating the reactants in a solvent-less system in the presence of an ortho directing catalyst while monitoring the amount of free formaldehyde present in the reaction system.
Claims13
Method of preparing a thermosetting 100 percent solids high-ortho phenol/formaldehyde resin useful as a hot melt adhesive comprising:
- (a) forming a reaction mixture comprising molten phenol and non-aqueous formaldehyde reactants present in a molar ratio of 1.2-1.7 moles of said non-aqueous formaldehyde per mole of said molten phenol, said reaction mixture being devoid of added solvent;
- (b) adding from about 0.02 to 10 wt. % of an ortho directing catalyst to said reaction mixture based on the weight of said phenol and formaldehyde;
- (c) heating said reaction mixture at a temperature of from about 110.degree.-125.degree. C. until substantially no free formaldehyde remains in said reaction mixture and wherein the refractive index approaches about 1.6";
- (d) allowing said reaction mixture to cool, thus forming a solid storage stable thermosetting phenol/formaldehyde resin having a molecular weight of between about 500 and 5,000 atomic mass units.
1 more element
Dependencies are inferred from the claim text.