Rounding of hard cover books
AssigneeNational Starch and Chemical Corporation
InventorsDavid G. Carter, Derek J. Green, Anthony J. Clark
Life of this patent
Estimating the term…
Abstract
Rounded, hard covered books are bound using a specific class of low viscosity reactive urethane hot melt adhesive compositions which provide a coating which will remain sufficiently flexible and thermoplastic so as to be capable of accepting and maintaining the rounded configuration even after extended periods of storage.
Claims19
A rounded hard cover book comprising a cased-in bookblock composed of a collected seris of signatures enclosed by means of end papers, the edges of which are coated with a solvent-free hot melt polyurethane adhesive composition which is solid at room temperature consisting essentially of:
- (a) 5 to 90% by weight of a urethane prepolymer having an isocyanate content of 0.25 to 15% and an isocyanate index greater than 1 and no more than about 2;
- (b) 10 to 95% by weight of a low molecular weight polymer of ethylenically unsaturated monomers containing no active hydrogen;
- said hot melt adhesive formulation being characterized, in the absence of tackifiers and/or plasticizers, by a viscosity of 3000 to 50,000 cps. at 120.degree. C.
In a process for binding rounded, hard covered books comprising the steps of:
- (1) printing, cutting, folding and enclosing collected signatures by means of end papers to form a bookblock;
- (2) passing the resultant bookblock into binding machinery;
- (3) applying an adhesive to the sewn or cut edges of the signatures;
- (4) allowing the adhesive to solidify;
- (5) rounding the bond signatures;
- (6) lining up the bound sheets;
- and (7) casing-in the bound book, the improvement which comprises using as the adhesives a solvent-free hot melt polyurethane adhesive composition which is solid at room temperature consisting essentially of:
- (a) 5 to 90% by weight of a urethane prepolymer having an isocyanate content of 0.25 to 15% and an isocyanate index greater than 1 and no more than about 2;
- (b) 10 to 95% by weight of a low molecular weight polymer of ethylenically unsaturated monomers containing no active hydrogen;
- said hot melt adhesive formulation being characterized, in the absence of tackifiers and/or plasticizers, by a viscosity of 3000 to 50,000 cps. at 120.degree. C.
Dependencies are inferred from the claim text.