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US 6,713,552 B1Granted
Pressure sensitive adhesive with improved peel strength and tack
AssigneeRohm and Haas Company
InventorsPatricia Marie Lesko, Robert M. Blankenship
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AssigneeRohm and Haas Company
InventorsPatricia Marie Lesko, Robert M. Blankenship
Estimating the term…
An aqueous composition suitable for use when dry as a pressure sensitive adhesive including an aqueous emulsion polymer formed by the free radical polymerization of at least one ethylenically unsaturated monomer at a reaction temperature lower than 100° C. in the presence of 20-1500 ppm, based on the total weight of the monomer, of an N-oxyl radical, the polymer having a glass transition temperature (Tg) from −80° C. to 0° C. is provided. Also provided is a method for preparing the emulsion polymer and a method for coating a substrate with an aqueous composition to provide a pressure sensitive adhesive layer on a substrate.
An aqueous composition suitable for use when dry as a pressure sensitive adhesive comprising an aqueous emulsion polymer formed by the free radical polymerization of at least one ethylenically unsaturated monomer selected from the group consisting of (meth)acrylic ester monomers, vinyl esters, vinyl chloride, vinylidene chloride, N-vinyl pyrollidone, and (meth)acrylamides, from 0% to 10%, by weight based on total monomer weight, of a monoethylenically-unsaturated carboxylic acid monomer, and from 0% to 1%, by weight based on monomer weight, multi-ethylenically unsaturated monomer selected from the group consisting of allyl methacrylate, diallyl phthalate, 1,4-butylene glycol dimethacrylate, 1,2-ethylene glycol dimethacrylate, and 1,6-hexanediol diacrylate at a reaction temperature lower than 100° C. in the presence of 20-1500 ppm, based on the total weight of said monomer, of an N-oxyl radical, said polymer having a glass transition temperature (Tg) from −80° C. to 0° C.
A method for preparing an aqueous emulsion polymer suitable for use in an aqueous pressure sensitive adhesive composition comprising:
Dependencies are inferred from the claim text.
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Term ended 25 Nov 2020 (estimated)
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This invention relates to an aqueous composition suitable for use when dry as a pressure sensitive adhesive having improved peel strength and tack, a method for preparing an aqueous emulsion polymer suitable for use in a pressure sensitive adhesive having improved peel strength and tack, and a method for coating a substrate with an aqueous coating composition to provide a pressure sensitive adhesive layer on the substrate, the adhesive layer having improved peel strength and tack. More particularly this invention relates to an aqueous composition suitable for use when dry as a pressure sensitive adhesive including an aqueous emulsion polymer formed by the free radical polymerization of at least one ethylenically unsaturated monomer at a reaction temperature lower than 100° C. in the presence of 20-1500 ppm, based on the total weight of the monomer, of an N-oxyl radical, the polymer having a glass transition temperature (Tg) from −80° C. to 0° C.
The present invention serves to provide an aqueous composition suitable for use when dry as a pressure sensitive adhesive, the adhesive being a permanently tacky film capable of adhering to a variety of substrates under slight pressure at ambient temperatures. Pressure sensitive adhesives are commonly applied to a substrate such as paper or a polymeric film, which construction may be used in the form of a label or tape having facile adhesion to a substrate of the same or different composition and form.
German Patent Application DE 197 27 502 discloses a method of radical-initiated aqueous emulsion polymerization in which monomers are polymerized in the presence of an N-oxyl radical by means of special radical polymerization initiators at temperatures above 100 C. and pressures above the vapor pressure of the polymerization mixture. The emulsion polymers are disclosed to be useful as binders for paints or leather finishes.
The following examples are presented to illustrate the invention and the results obtained by the test procedures.
Abbreviations
AA=acrylic acid