Pressure-sensitive crayon adhesive
AssigneeBorden, Inc.
InventorsPeter S. Columbus, Yogeshbhai B. Patel
Life of this patent
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Abstract
This invention relates to thermoplastic, pressure-sensitive solid adhesives capable of transferring an adhesive film to a substrate by friction rubbing of the adhesive on the substrate. The adhesives of this invention consist essentially of polyisobutylene, wax and optionally an adhesive promoter resin. Said ingredients are within certain proportions, molecular weights, melting points, or hardness values.
Claims31
A solid thermoplastic and pressure-sensitive crayon adhesive consisting essentially of an intimate mixture of:
- A. from about 40% to 75% by weight of polyisobutylene having a Flory molecule weight of 40,000 to 70,000;
- B. about 25% to 60% by weight of synthetic wax having a needle penetration value of from about 1 to 6 and a melting point of at least 190.degree. F.;
- and
- C. optionally containing up to about 30% by weight of an adhesion promoter resin for the polyisobutylene wherein said resin has a softening point above 150.degree. F. and is a member selected from the group consisting of rosin, modified rosin, a rosin derivative, a terpene resin, a hydrogenated resin, a resin prepared from a C-5 aliphatic hydrocarbon, and a resin prepared from a mixture of a C-5 aliphatic and a C-9 aromatic hydrocarbon;
- and wherein the total quantity of polyisobutylene, wax, and resin make up at least 90% of the crayon.
A thermoplastic and pressure-sensitive adhesive mass capable of transferring an adhesive film to a paperlike substrate by friction rubbing and consisting essentially of a substantially homogeneous mixture of:
- A. about 40% to 65% of polyisobutylene having a Flory molecular weight of from about 40,000 to 70,000;
- B. about 25% to 60% of a wax having a melting point of at least 165.degree. F. and a needle penetration value of from about 1 to 15;
- and
- C. about 10% to 25% of an adhesion promoter resin for the polyisobutylene, said resin having a softening point of from about 176.degree. to 248.degree. F. and is a member selected from the group consisting of rosin, modified rosin, a rosin derivative, a terpene resin, a hydrogenated resin, a resin prepared from a C-5 aliphatic hydrocarbon, and a resin prepared from a mixture of a C-5 aliphatic hydrocarbon and a C-9 aromatic hydrocarbon;
- and wherein the wax has a needle penetration value of not greater than 8 when the mass contains at least 10% of the resin.
A solid, thermoplastic, pressure-sensitive crayon adhesive having the characteristics of becoming softer and less cohesive at the area of contact and under the influence of frictional heat generated when an exposed area of the crayon is drawn rapidly in frictional contact with a smooth, dry, paperlike, surface and then being capable of transferring a thin, continuous layer of the softening adhesive to the said day surface, said crayon:
- A. when stored at a temperature of 140.degree. F. for one week being (a) free from melting or deforming, and (b) free from ingredient separation and bleeding;
- B. having a milky white to translucent color in the absence of a coloring agent;
- C. being capable of transferring a clear adhesive film on said paperlike substrate and forming a fiber tearing bond after another piece of paperlike substrate is placed in contact with the transferred adhesive film and a pressure of at least 15 pounds per square inch is applied over the area of said substrates in contact with the film at room temperature for 10 seconds;
- and
- D. wherein the crayon adhesive consists essentially f a substantially homogeneous mixture of:
- (a) about 40% to 65% of polyisobutylene having a Flory molecular weight of about 40,000 to 70,000;
- (b) from about 25% to 40% of a synthetic wax having a needle penetration value of from about 1 to 6 and a melting point of at least 190.degree. F.;
- and
- (c) from about 10% to 20% of an adhesion promoter resin for the polyisobutylene, said resin having a softening point of about 176.degree. F. to 248.degree. F. and is a member selected from the group consisting of rosin, modified rosin, a rosin derivative, a terpene resin, a hydrogenated resin, a resin prepared from a C-5 aliphatic hydrocarbon, and a resin prepared from a mixture of a C-5 aliphatic and C-9 aromatic hydrocarbon.
A solid, thermoplastic, pressure-sensitive crayon adhesive, said adhesive:
- A. being normally tacky;
- B. capable of transferring a thin, smooth, and continuous layer of adhesive film to a paperlike substrate by friction rubbing on said substrate;
- C. forming a permanent bond after another paperlike substrate is pressed against the transferred adhesive film;
- and
- D. having a composition consisting essentially of
- (1) from about 40% to 75% by weight of polyisobutylene having a Flory molecular weight of 40,000 to 70,000
- (2) about 25% to 60% by weight of wax having a needle penetration value of from about 1 to 15 and a melting point of at least 165.degree. F. and
- (3) optionally containing up to about 30% by weight of an adhesion promoter resin for the polyisobutylene wherein said resin has a softening point above 150.degree. F. and is a member selected from the group consisting of rosin, modified rosin, a rosin derivative, a terpene resin, a hydrogenated resin, a resin prepared from a C-5 aliphatic hydrocarbon, and a resin prepared from a mixture of a C-5 aliphatic and a C-9 aromatic hydrocarbon;
- and provided that the was has a needle penetration value of not greater than 8 when at least 10% of adhesion promoter resin is in the composition and wherein at least 90% of the adhesive consists of polyisobutylene, wax, and adhesion promoter resin.
Dependencies are inferred from the claim text.