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US 4,902,370 AGranted
Synthetic based cold seal adhesives
AssigneeNational Starch and Chemical Corporation
InventorsRichard A. Dust, Peter Causton
Life of this patent
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Abstract
This invention presents a series of synthetic based cold seal adhesives which are capable of forming a strong bond at room temperature, yet which may be reeled up without blocking and stored for extended periods of time. Such adhesives can be used in place of the natural rubber based cold seal adhesives currently used, and thus, can be employed in any packaging application where cold seal properties are desirable.
Claims6
A method for forming a cold seal bond on a substrate comprising
- (i) coating all or a portion of said substrate with an effective amount of emulsion containing a cold seal adhesive composition, wherein said cold seal adhesive composition comprises about 45 to 70% (by wt.) of a synthetic base polymer and about 30 to about 55% (by wt.) of a synthetic secondary polymer, wherein the base polymer comprises a synthetic polymer, a synthetic copolymer, or any mixture thereof characterized in that it possesses a Tg of about -40.degree. to about -60.degree. C. and a Williams plasticity number of about 2.5 to about 2.9;
- and secondary polymer comprises a styrene-acrylic copolymer, a stryene-acrylic resin, or any mixture thereof, or an admixture of one or more styrene-acrylic copolymers, styrene-acrylic resins, or any mixture thereof, with one or more synthetic polymers, synthetic copolymers, or synthetic resins characterized in that it possesses a Tg of about -25.degree. to about +5.degree. C. and a plasticity number of about 5.0 to about 5.6;
- (ii) drying said emulsion to form a dried film;
- and
- (iii) subsequently bringing the coated portions of the substrate into contact with each other such that a bond is effected.
2 more elements
Dependencies are inferred from the claim text.