Wet glue

Abstract

An aqueous adhesive composition including a certain emulsion polymer and an epoxysilane wherein the adhesive composition is substantially free from crosslinking agent is provided. A method for providing a substrate bearing a paper label, the adhered label having ice water resistance, and a method for removing the paper label from the substrate are also provided.

Claims

1. A method for providing a substrate bearing a removable paper label, the method comprising: forming an aqueous adhesive composition substantially free from crosslinking agent, the adhesive composition comprising: an emulsion polymer comprising, as copolymerized units, from 10% to 35%, by weight based on the emulsion polymer weight, carboxylic acid monomer and at least one second ethylenically unsaturated monomer; and from 0.1% to 4%, by weight based on the emulsion polymer dry weight, an epoxysilane; applying the aqueous adhesive composition to a paper label; drying or allowing to dry the applied adhesive composition on the paper label, thereby forming the removable paper label; and applying the removable paper label to the substrate.

2. The method of claim 1, wherein drying or allowing to dry the applied adhesive composition is effected under ambient conditions.

3. The method of claim 1, wherein drying or allowing to dry the applied adhesive composition is effected at 0 C. to 35 C.

4. The method of claim 1, wherein the epoxysilane is present in the adhesive composition from 1.5% to 3.0%, by weight based on the emulsion polymer dry weight.

5. The method of claim 1, wherein the epoxysilane is a glycidoxyalkyl trimethoxy silane.

6. The method of claim 1, wherein the emulsion polymer is an alkali-swellable polymer.

7. The method of claim 1, wherein the carboxylic acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, monomethyl itaconate, monomethyl fumarate, monobutyl fumarate, maleic anhydride, and combinations of two or more thereof.

8. The method of claim 1, wherein the at least one second monoethylenically unsaturated monomer is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ureido-functional (meth)acrylates, acetoacetates, acetamides or cyanoacetates of (meth)acrylic acid, styrene or substituted styrenes, vinyl toluene, butadiene, vinyl acetate or other vinyl esters, vinyl chloride, vinylidene chloride, N-vinyl pyrollidone, (meth)acrylonitrile, N-alkylol (meth)acrylamide, and combinations of two or more thereof.

9. The method of claim 1, wherein the adhesive composition further comprises at least one multiethylenically unsaturated monomer selected from the group consisting of allyl (meth)acrylate, diallyl phthalate, butadiene, 1,4-butylene glycol di(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, divinyl benzene, and combinations of two or more thereof.

Description

EXPERIMENTAL TEST METHODS

(1) Ice Water Resistance

(2) Wet adhesives were applied to labels with a Meyer bar at a dry level of 5-8 g/m2. Labels with the dimensions 6080 mm were used.

(3) The labels attached to glass bottles were stored for 4 days at ambient temperature. After storage, the bottles were filled with water and immersed in an ice water bath. The time until the labels became detached was noted. A value of 5 days or greater in this test is rated as passing.
Wash-Off Test.

(4) This test procedure was used for the testing of the detachability of adhesives in a hot, aqueous alkaline solution.

(5) Wash-off ability is the ability of an adhesive to detach itself quickly and completely in a 1.0-2.0% solution of sodium hydroxide at 65-75 C. Labels with the dimensions 6080 mm were used.

(6) The labels attached to glass bottles were stored for at least 24 hours under standard climate conditions: 23 C.2 C., 50% RH5% RH. After storage, the bottles were filled with water at the testing temperature and immediately immersed in the solution of sodium hydroxide at the testing temperature.

(7) The time until the labels became detached and the location of the adhesive after the label had detached were noted. A value of 5 minutes or less in this test is rated as passing.

(8) The following examples serve to illustrate the invention.

ABBREVIATIONS USED

(9) TABLE-US-00001 Ethyl acrylate EA Butyl acrylate BA 2-Ethylhexyl acrylate EHA Methyl methacrylate MMA Butyl methacrylate BMA Methacrylic acid MAA Styrene Sty

(10) Aqueous emulsion polymer compositions (weight basis):

(11) Emulsion polymer A=p(50 EA/3 Sty/25 MMA/18 MAA)

(12) Emulsion Polymer B=p(80 EA/20 MAA)

(13) Emulsion Polymer C=p(62 BMA/38 MAA)

(14) Emulsion Polymer D=p(56EA/5EHA/36MAA)

Examples 1-2 and Comparative Examples A-B. Formation and Evaluation of Aqueous Adhesive Compositions

(15) The aqueous adhesive compositions were applied to a paper label at a level of 24 g/m2 wet with a No. 3 bar and dried for 4 days at ambient conditions.

(16) TABLE-US-00002 Example 1 2 Comp. A Comp. B Polymer B + Polymer A + Polymer D + Polymer C + 2% SILQUEST 2% SILQUEST 2% SILQUEST 2% SILQUEST A-187 A-187 A-187 A-187 Solids % 35.3 29.4 8.5 30.7 pH 7.1 8.1 7.8 7.26 Add-on (24 g/m.sup.2 wet with bar n.sup.o3) dry (5-8 g/m.sup.2) 8 6.6 5.9 6.8 Ice water resistance >15 days 6 days >15 days 3 hours Wash-off test (Finat 4 min < wash off < 1 min >5 min NA FTM26)* (minutes) 5 min no adhesive no adhesive remained remained on the bottles on the bottles *soda bath at 1.5%/temperature: 71.4 C.

(17) SILQUEST A-187 is an epoxy functional silane from Momentive Specialty Chemicals Inc. (Columbus, Ohio).

(18) The aqueous adhesive compositions, Examples 1-2, of the invention exhibited desirable levels of ice water resistance and wash off performance