Adhesive system for wood bonding applications
The invention is directed to an adhesive system for wood containing a synergistic mixture of melamine-formaldehyde resin, phenol-formaldehyde resin, and cross-linked polyvinyl acetate emulsion resin wherein the mixture is cured by an acid.
1 . An adhesive system comprising a mixture of:
a) a melamine-formaldehyde resin;
b) a phenol-formaldehyde resin; and
c) a cross-linkable polyvinyl acetate emulsion resin, wherein the mixture is cured with an acid.
2 . The adhesive system of claim 1 , wherein the melamine-formaldehyde resin is present in an amount ranging from about 5 to about 50 wt. %, based on the total weight of the mixture.
3 . The adhesive system of claim 1 , wherein the phenol-formaldehyde resin is present in an amount ranging from about 10 to about 50 wt. %, based on the total weight of the mixture.
4 . The adhesive system of claim 1 , wherein the cross-linkable polyvinyl acetate emulsion resin is present in an amount ranging from about 23 to about 72 wt. %, based on the total weight of the mixture.
5 . The adhesive system of claim 1 , wherein the acid is a 95% solution of formic acid in water.
6 . The adhesive system of claim 5 , wherein the formic acid is present in an amount ranging from about 1 to about 20 wt. %, based on the total weight of the mixture.
7 . The adhesive system of claim 1 , wherein the acid is a 70% methane sulfonic acid solution in water.
8 . The adhesive system of claim 7 , wherein the methane sulfonic acid is present in an amount ranging from about 1 to about 20 wt. %, based on the total weight of the mixture.
9 . The adhesive system of claim 1 , wherein the acid is a 70% toluene sulfonic acid solution in water.
10 . The adhesive system of claim 9 , wherein the toluene sulfonic acid is present in an amount ranging from about 1 to about 20 wt. %, based on the total weight of the mixture.
11 . The adhesive system of claim 1 , wherein the acid is aluminum chloride.
12 . The adhesive system of claim 11 , wherein the aluminum chloride is present in an amount ranging from about 1 to about 20 wt. %, based on the total weight of the mixture.
13 . The adhesive system of claim 1 , wherein the mixture has a pH ranging from about 1 to about 5.
14 . The adhesive system of claim 1 , wherein the mixture has a pH ranging from 3.5 to 4.5.
15 . The adhesive system of claim 1 , wherein the mixture is cured with heat.