Abstract An aqueous starch-based adhesive comprising: (a) water; (b) corn starch or wheat starch; (c) a carboxylated styrene-butadiene latex; (d) a thickener; and (e) a crosslinking agent. The thickener and cross-linking agent are collectively present as a minor component. A preferred thickener is a mixture of hydroxyethylcellulose and ammonia and the preferred crosslinking agent is a mixture of a ureaformaldehyde resin and glyoxal. The adhesive has a solids content of between about 35 and about 50 weight percent and pH ranging from about 4.5 to 7.0. The aqueous adhesive can be used to provide corrugated paperboard at rates ranging from 300 to 550 linear feet/minute and has a stable pot life of up to one week. It results in little or no corrosion to corrugating equipment and can be used in the same application and storage systems with conventional starch adhesives. Preparation of the adhesive is simplified because it need not be heated. The adhesive cures in a time period of less than 2 hours and can be used in smaller amounts than conventional alkaline adhesives.
A method for adhesively bonding two adjoining surfaces of a fluted medium and a liner of paperboard, which comprises applying an aqueous corrugating adhesive comprising: (a) water; (b) corn or wheat starch; and (c) a carboxylated styrene-butadiene copolymer latex; and further comprising as minor components; (a) a thickener; and (b) a cross-linking agent to said liner or to the tips of said fluted medium.
Claim 2
Independent Claim
64 words
A method for adhesively bonding two adjoining surfaces of a fluted medium and a liner of paperboard, which comprises applying an aqueous corrugating adhesive comprising: (a) water; (b) corn or wheat starch; and (c) a carboxylated styrene-butadiene copolymer latex; and further comprising as minor components; (a) a thickener; and (b) a cross-linking agent to said liner or to the tips of said fluted medium.
Claim 3
Dependent Claim
87 words
The method of claim 1, wherein said adhesive comprises: (a) water in an amount ranging from about 25 and about 54 weight percent; (b) corn or wheat starch in an amount between about 25 and about 38 weight percent; (c) a carboxylated styrene-butadiene latex in an amount of between about 17 and about 47 weight percent; (d) a thickener in an amount of between about 0.1 and about 1 weight percent; (e) a cross-linking agent in an amount of between about 0.5 and about 5 weight percent.
Claim 4
Dependent Claim
25 words
The method of claim 1, wherein said adhesive additionally comprises an alkaline material in an amount of between about 0.05 and about 0.1 weight percent.
Claim 5
Dependent Claim
24 words
The method of claim 3, wherein said thickener comprises hydroxyethylcellulose, said cross-linking agent comprises a urea-formaldehyde or melamine-formaldehyde resin and said base comprises ammonia.
Claim 6
Dependent Claim
24 words
The method of claim 3, wherein said thickener comprises glyoxal and a urea-formaldehyde resin in a weight ratio of glyoxal to urea-formaldehyde of 3:2.
Claim 7
Dependent Claim
10 words
The method of claim 1, wherein said starch is uncooked.
Claim 8
Dependent Claim
16 words
The method of claim 5, wherein said adhesive is cured in less than about two hours.