Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1999-12-27
2002-03-05
Truong, Duc (Department: 1711)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S423100, C428S425500, C525S452000, C525S453000, C525S454000, C525S458000
Reexamination Certificate
active
06352768
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to ink-imprintable or ink-receptive release coating compositions and to ink-cancelable self-adhesive postage stamps.
BACKGROUND OF THE INVENTION
The postage stamp is a rather complex device. To meet current user demands it must be constructed of a face material or backing capable of accepting high quality printing of complex design. The stamp must also be stable under a variety of environmental conditions and provide an ink-cancelable surface on which the cancellation ink dries rapidly. In addition to being cancelable, the stamp should have means to detect the stamp so that a properly stamped envelope can be cancelled in an automated cancellation machine. The means to detect the stamp may be either in the ink cancelable surface or in the paper used to prepare the stamp prior to printing.
Traditionally, postage stamps have been manufactured with a water-soluble, water-activated adhesive. It has been the desire of the postal service to not only convert the adhesive to a self-adhesive or pressure-sensitive adhesive, but to also present such postage stamps in traditional and new formats. One new format provides self-adhesive stamps which are dispensable from an automatic teller machine. An old format provides stamps which are dispensable from a self-wound tape or roll.
A self-wound construction comprises a tape which, in the case of stamps, provides a plurality of contiguous stamps marked at regular intervals along the length thereof to indicate where a die cut is to be made to separate the stamps. The back surface of the stamps is coated with a layer of pressure-sensitive adhesive. The opposed or face surfaces of the stamps must provide an ink-cancelable surface. When the stamps are wound on themselves to form a roll, the pressure-sensitive adhesive comes into contact with the face surface of another stamp. The adhesive adheres to the face, and it is then difficult to impossible to unwind the roll without damage to the face or printed surface. It is possible to reduce the adhesion of the pressure-sensitive adhesive to the face surface of the stamp constructions by applying a release coating to the face surface of the stamps which is capable of reducing the strength of adhesive bond between the pressure-sensitive adhesive and the face of the stamp construction when in the form of a self-wound tape or roll.
U.S. Pat. No. 5,082,704 describes a filmic release sheet for asphalt roofing sheets. The release composition includes a polydimethylsiloxane diol or triol, an organic isocyanate, an organic polyol, a compound with a hydrophilic center and isocyanate—reactive groups, and a chain extender.
U.S. Pat. No. 5,165,976 describes a substrate which is provided with a release surface by application of an emulsion. The emulsion is a blend of a vinyl-addition silicone system, a catalyst therefor, and a particulate component which may be inorganic or organic in nature but which is preferably a resin. Each of the components of the emulsion are themselves an emulsion. The vinyl-addition silicone system is cured by application of heat and removal of water. The products may be used in the full range of release applications, especially pressure-sensitive adhesive roll stock, and can be converted at high speeds.
U.S. Pat. No. 5,356,706 describes a modified silicone copolymer useful as a release agent. The modified silicone is the reaction product of a di-omegaorgano functional dimethylsiloxane oligomer having terminal active hydrogen groups, a carboxyl group bearing monomer, and a diisocyanate. The copolymer is reported to provide good release properties from tacky adhesive masses.
U.S. Pat. No. 5,478,880 describes a release composition for a repositionable adhesive. The release composition is described as a mixture of an ethylene vinyl chloride copolymer and a polyethylene emulsion.
U.S. Pat. No. 5,492,599 describes a treated cellulose-based substrate. The substrate is coated with a cationic polymer primer coating and a release coating with pendant carboxyl or carboxylate moieties.
U.S. Pat. No. 5,496,635 describes a directly printable composition. The composition is a reaction product of a vinyl-functional monomer, and a chlorinated olefinic resin. The reaction product optionally includes an amide-functional monomer and a free radically polymerizable silicone-containing material.
U.S. Pat. No. 5,543,171 describes an aqueous solution of a dimethylsiloxane containing polyelectrolyte. The solution incorporates polydimethylsiloxane blocks, polar groups, and anionic groups, and is reported to provide slip, water repellency, and good release from pressure sensitive adhesives.
U.S. Pat. No. 5,547,738 describes production of linerless label stock by moving a single substrate through a coating machine and applying a tie coating to the substrate first face, a release coating to the substrate second face, and a pressure sensitive adhesive to the tie coating.
U.S. Pat. No. 5,663,227 describes a release agent for linerless pressure sensitive postage stamps, preferably an organopolysiloxane polyurea block copolymer, containing a dispersion of calcium carbonate and polyvinyl pyrrolidone.
European patent publication number 905210 describes a combination of an aqueous silicone release emulsion with an aqueous polyurethane emulsion to create a mixed release emulsion that cures to a linerless release coating which is printable when applied to a substrate such as paper.
Other patents which describe release coatings include U.S. Pat. Nos. 5,674,626; 5,663,227; 5,621,020; 5,569,515; 5,290,615; and 5,154,962.
The present invention is directed to providing ink-imprintable release coating compositions and an ink-cancelable release surface for application to the face side of pressure-sensitive adhesive stamp constructions and the like.
SUMMARY OF THE INVENTION
Ink-imprintable release coating compositions are provided which comprise a reaction product of a mixed emulsion containing a carboxylic acid terminated polydimethylsiloxane, a hydrophilic isocyanate reactive agent, a polyisocyanate, and at least one a dihydroxy terminated oligomer. Ink-imprintable stamp constructions also are provided which comprise a plurality of contiguous stamps in a roll or stacked sheet configuration without an independent release liner wherein the stamps have a pressure-sensitive adhesive on the back surface of the stamps and a, the above stated, cured ink-imprintable release coating on the face surface of the stamps.
In one embodiment, the ink-imprintable release coating compositions of the present invention comprise a reaction product of a mixed emulsion containing (A) a carboxylic acid terminated polydimethylsiloxane; (B) a hydrophilic, isocyanate reactive agent; (C) a polyisocyanate; and (D) at least one dihydroxy terminated oligomer.
In a preferred embodiment, the ink-imprintable release coating compositions of the present invention comprise a reaction product containing a mixed emulsion containing (A) a carboxylic acid terminated polydimethylsiloxane; (B) a hydrophilic, isocyanate reactive agent; (C) a polyisocyanate; and (D) at least one dihydroxy terminated oligomer, wherein the reaction product further contains the residue of an ionizing tertiary amine and chain extending aliphatic diamine.
In another embodiment, the ink-imprintable release coating compositions of the present invention comprise a reaction product of a mixed emulsion containing (A) an isocyanate terminated polydimethylsiloxane; (B) a hydrophilic, isocyanate reactive agent; (C) a polyisocyanate; and (D) at least one of a dihydroxy terminated oligomer.
In yet another embodiment, the ink-imprintable release coating compositions of the present invention comprise a reaction product of a mixed emulsion containing (A) an isocyanate terminated polydimethylsiloxane; (B) a hydrophilic, isocyanate reactive agent; (C) a polyisocyanate; and (D) at least one of a dihydroxy terminated oligomer, wherein the reaction product further contains the residue of an ionizing tertiary amine and chain extending aliphatic diamine.
In another emb
Dordick Robert S.
Hseih Dong-Tsai
Meader Christopher D.
Su Wen-Chen
Avery Dennison Corporation
Renner Kenner Greive Bobak Taylor & Weber
Truong Duc
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