Producing adhesively edge-padded paper tablets with a fast-drying latex adhesive
AssigneeMinnesota Mining and Manufacturing Company
InventorsClair J. Emery, Kenneth J. Perrington
Life of this patent
Estimating the term…
Abstract
A latex adhesive made from a polymer such as a ethylene/vinyl acetate or styrene/butadiene copolymer, a low-boiling alcohol, such as isopropanol, a non-crystallizing polyhydric alcohol such as sorbitol, and preferably a cellulose thickener. The latex adhesive dries so quickly that an adhesively edge-padded stack of paper sheets formed using the adhesive can be cut by hand into tablets within about 30 minutes. These tablets do not leave an upstanding ridge of adhesive when a number of the sheets are torn off.
Claims18
A method for producing adhesively edge-padded tablets comprising the steps of:
- 1) adhesively edge-padding a stack of paper with a latex adhesive which has a viscosity at room temperature of from about 600 to about 8000 cps and consists of by weight:
- a) from about 25 to about 40 parts (dry basis) of a latex of a polymer having a Tg from about -10.degree. to about 30.degree. C., which when blended with a non-crystallizing polyhydric alcohol is film-forming,
- b) from about 10 to about 22 parts of at least one low-boiling alcohol,
- c) from about 3 to about 9 parts of at least one non-crystallizing polyhydric alcohol, and
- d) water in an amount to provide 100 parts of ingredients a) through d), and
- 2) allowing the applied latex adhesive to dry.
A latex adhesive having a viscosity at room temperature of from about 600 to about 8000 cps and is useful for adhesively edge-padding a stack of paper that is to be cut into tablets, said latex adhesive consisting of by weight:
- a) from about 25 to about 40 parts (dry basis) of a latex of a polymer having a Tg from about -10.degree. to about 30.degree. C., which latex when blended with a non-crystallizing polyhydric alcohol is film-forming,
- b) from about 10 to about 22 parts of at least one low-boiling alcohol,
- c) from about 3 to about 9 parts of at least one non-crystallizing polyhydric alcohol, and
- d) water in an amount to provide 100 parts of ingredients a) through d).
Dependencies are inferred from the claim text.