Pressure sensitive adhesive forming compositions

Pressure sensitive adhesive forming compoBitions

ΪΜ AND HM.8 COMPANY

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54389/2־ '

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ף. This invention is concerned with improvements in pressure sensitive adhesive compositions prepared from addition polymers, ₀ particularly addition polymers obtained from acrylic monomers by emulsion polymerization or equivalent methods, and articles made therewith.

]Pressure sen׳si'tive adhesive compositions have in the past been prepared from aqueous polymer dispersions, including dispersions of polymers having pendant carboxylic acid groups in acid or salt form.' Examples of such compositions are disclosed in U.S, Patents Nos. 2,976,205 and 2,976,204. It is also known to cross-link suoh polymers in adhesive compositions, and other polymers containing functional groups, by reaction with crosslinking agents, e.g, epoxides. .i ' י Γ

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One of the problems in obtaining useful pressure sn^sitive . adhesive compositions is the relationship of tack to shear resistance. Often if an adhesive is modified to increase tackiness, its resistance to shearing is lowered, and commonly an increase in shear resistance 1ן accompanied by a reduction in tackiness,

It has now been found that improved shear resistance is obtained in pressure sensitive adhesive compositions based on addition polymers containing free carboxylic groups, by including in a dispersion or solution of the polymer in a suitable liquid medium a polyvalent metal compound. Usually, but not necessarily the media will be an aqueous media, in which case it is postulated that the polyvalent metal compound dissociates to z 1 ‘I provide .polyvalent metal ions or polyvalent metal-containing ions which act to cross-link the₍carboxylate groups upon removal of the aqueous media.

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Surprisinly, it i□ found that the improved shear resistance is obtained without any appreciable loss of tackiness. Furthermore, a valuable ׳ and unexpected property of the adhesive compositions of this invention is that they are resistant to removal by alkaline solutions, parti0.111 ¢11-1 y when the.carboxylic acid monomer is used at a low level.

According to this invention, therefore, there is provided a composition which, upon removal of the liquid medium and heating forms a pressure sensitive adhesive, said composition comprising A) a dispersion or solution of an audition polymer in a liquid medium, said polymer being Obtained from a monomer charge containing i) from 0.3 to 3.5 parte by weight per 100 parts by weight of the total monomer charge of one or more ethylenically unsaturated carboxylic acids, ' ii) one or more monoethylenically unsaturated compounds which v.hen J hbmopolyiaerised yield a homopolymer having a Tg not exceeding 0״C, and, optionally, iii) one or. more monoethylenically unsaturated compounds which when homopolymerised yield a homopolymer having a Tg above 0°0,, the relative amounts of monomer specified under ii) and iii) if present, j . 1 being such that the polymer hasji Tg not exceeding 0״C, and B) a compound. ! of. a polyvalent metal from Group lb, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VIA, VIB, VIIB, or VIII of the Mendeleeff Periodic Table, said compound being at least partially soluble in the/liquid medium and the equivalency ratio of polyvalent metal ion to carboxyl groups in the composition

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being from 0.01:1 to 2.0:1.

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Also included within the scope of this invention are articles having; , adhesive on a surface thereof a coating of pressure senoitive/deposited from a’ composition as specified above, and a method of bonding two surfaces together, which comprises applying to one or both surfaces a coating of a composition as defined above, drying and heating tho coating to deposit on the surface a layer of pressure sensitive adhesive, and thereafter ׳

34589/2 ׳ pressing the surfaces together. . ¹

As indicated, one of the monomer(c) utilized in a substantial proportion to prepare the polymer base of the adhesive compositions of this invention is a monomer which when homopolymerised yields a homopolymer having a־ Tg not exceeding 0°C,, such monomers being !mown in the art as taolcifying or soft monomers. An optional component is a hard monomer, i.e. one Which, when homopolymerised yields a homopolymer having a Tg above 0°C., it being provided that the amount of hard . monomer is not such that the overall Tg of the polymer exceeds 0°C. Preferably the overall Tg of the polymer is below -15’0.

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By way of explanation Tg is a conventional criterion of polymer I hardness and is described by Flory, Principles of Polymer Chemistry, ! pp. j6 and 57, (1955), Cornell University Press. While actual measurement of the Tg is preferred, it may be calculated as described by Pox, Bull. Am. Physics Soo. 1., 3, p. 123 (1956)., Examples of the Tg of ׳ homopolymers and the .inherent Tg thereof which permits such calculations are as follows:

Homopolymer of Tg n-oetyl acrylate-80’c

-׳' n-decyl methacrylate -60 °C

2-ethylhexy acrylate-70'C . octyl methacrylate ., -20°C nrtetradecyl methacrylate- 9 0 methyl acrylate9 n-tetradecyl acrylate20°C methyl methacrylate105’0 acrylic acid106°C

The soft monomers used in preparing the polymer base of the adhesive compositions of this invention will preferably be monoethylenioally unsaturated compounds of the formula: _.

Λ U CHg=0׳—C—OH' '

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34389/2 » wherein R is. H or C-j-C^ alkyl and R' ic a primary or secondary allcyl, .

alkoxyalkyl or allcyl thioalkyl radical having from 2-14 carbon atoms, examples being ethyl, propyl, ή-butyl, 2-ethylhexyl, heptyl, hexyl, ootyl, ; propyl, 2-methylbutyl, 1-methylbutyl, butoxybutyl, 2-methylpentyl,. ’ methoxymethyl, ethoxyethyl,. n-hexyl, isobutyl, ethylthioethyl, methyl- ^,I׳ thioethyl, ethylthiopropyl, n-octyl, 6-methylnonyl, decyl and dodecyl.;

Mien R is E and R' is alky/, R* will have from 2-12 carbon atoms to Qualify as a soft monoftier, and when R is alkyl and R¹ is alkyl, R' will then have from 6-14 oarbon atoms to qualify as a soft or tackifying monomer.i

In addition to the soft monomer, the other essential monomer is I{

Ij an ethylenically ;unsaturated carboxylic acid, examples being sorbio, j | cinnamic, vinyl furoic, a-chlorosorbic, p-vinylbenzoio, acrylic, metha- I / , I . .' orylic, maleic, fumaric, aconitic, atropio, crotonic, or itaconio aoid, or a mixture of two or more thereof. Preferred carboxylic acid monomers are α,β-unsaturated monocarboxylic acids, particularly methacrylic acid and| acrylic acid, and itaconic acid. ^ci ;

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- . The hard monomers which-may optionally be used in combination with j the above-mentioned soft monomers end acid monomers, provided they do not ii . adversely affect the desired properties of the adhesive (e.g., unduly‘ .

raise the overall Tg of the polymer) end do not seriously interfere with»' the cross-linking by the polyvalent metal, are preferably of the formulas

RO ‘ :

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H₀C=C-C-OR '* . . '1 I wherein R is R.or alkyl, R² !6 methyl or O^-^O ^{vhGn R is H} ' I and is C_x-C₅ or C^-C^ alkyl when R is ף-ף alkyl. It can be seeni from above that for alkyl acrylates and alkyl methacrylates the Tg atj first decreases with an increased chain length of the alkyl group and thon the Tg again increases i.e. the allyl acrylates and alkyl methacrylates are hard or soft depending on chain length. Examples of these hard

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monomers and other hard monomers include: methyl acrylate, acrylamide, vinyl acetate, tetradecyl acrylate, pentadecyl acrylate, methyl methacrylate, ethyl methacrylate, t-butyL. acrylate, n-butyl methacrylate, styrene, pentadecyl methacrylate, vinyl toluene, methacrylamide, N-methylolacrylamide.

Mie specific amounts of hard and soft monomer are not critical, provided that the product polymer has a Tg not exceeding 0°C., preferably not exceeding -15*C. As a general guide, however, the following !

proportions can be givens ’ ί 'י י . . . . i ' Parts by Weight / 100 parts of monomer charge ’ ׳' ' Broad Range Preferred Range

Soft Monomer 10^99.7 70-99.5

Carboxylic aoid monomer 0.30.5-3,5 ' 3.5־

Hard Monomer Ο-89.7 0-29,-5

Mie preferred polymers used in the present invention are emulsion polymers having a molecular weight in the range 70,000 to 2,000,000, more, preferably from 250,000 to 1,000,000, Such polymers may be prepared by ' conventional emulsion polymerisation techniques, such as are described for example in U.S. Patents Nos. 2,754,200 and 2,795,564. Thus, the ‘י monomers may be emulsified with an anionic, a cationio, or a nonionio' dispersing, agent, from 0.05 percent to 10 percent thereof ordinarily . being used on the weight of the total monomers. The acid monomer is usually j soluble in water so that the dispersing agent eerves to emulsify tho other ί two monomers. A polymerisation initiator of the free radical type, ouch as ammonium br potassium persulfate, may be used alone or in conjunction with

I, 1¢. an accelerator, such as potassium metabisulfite, or sodium thiosulfate. Organic peroxides, such as benzoyl ~.

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:.I peroxide and i״butyl hydroperoxide are also useful initiators. ;

‘ The initiator’and accelerator, commonly referred to as׳ catalyst,, ^,)nay be used in proportions of ,0.1 percent to 10 percent each based on the weight of monomers to be copolymerized.

_ 5 י The amount, as indicated above, may be adjusted to control the ׳:.,. . , .,i intrinsic viscosity of the polymer. The temperature may be from'room temperature to 60°C. or more as is conventional. .

Suitable dispersing agents useful in emulsion poly-!

. merization include anionic types such as'the sodium salts of • ., 10 the higher fatty acid sulfates, such as that of laurylί . . .' . alcohol, the higher fatty acid salts, such as the oleates orj . stearates or morpholine, 2-pyrrolidone, triethanolamine or .mixed ethanolamines, or any of the nonionic types, such as:

\ethylene bxide-modified alkyl phenols, of which tert-octyl

ן י > * '15 phenol modified by 20 to 40 ethylene oxide units is ί .׳ . ׳: ί. ׳ j representative, ethylene oxide-modified higher fatty alcohols.. .

׳ r such as lauryl alcohol, containing 20 to ?0 ethylene oxide units, and similarly modified lorig-.chain mercaptans, fatty acids and aminesj. Mixtures of nonionic and anionic dispersing agents are also useful. |

Although aqueous emulsion polymers are preferred, polymers prepared in organic solutions, e.g., in xylene or methyl Cellosolve׳ (Registered Trademark) by well known conventional means such as free radical initiation with benzoyl peroxide are also useful. Solution polymers >* useful in the invention preferably have a molecular weight of from about 10,000 to 1,000,000. 'ן ’

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J . The polyvalent metal compound used in the compositions of thio ' invention may be either a simple ionic compound or a metal complex or a metal chelate, the only requirement being that it is at least partially ionizable or ooluble in the system. Preferably, the polyvalent metal ' >'־,. is selected from Groups IIB or IVB of the Mandeleeff Periodic Table, .; Typical.polyvalent metals usable in the invention include: copper, gallium, ,׳ . tin, cerium, titanium, vanadium, chromium, molybdenum, manganese, iron, ! cobaltnickel, beryllium, cadmium, calcium, magnesium, zinc, zirconium, ן barium, strontium, aluminum, bismuth, antimony, lead and cobalt,these being ¹ added to the composition as an oxide, hydroxide, or basic, acidic, or beutral salt or other compound or complex which has appreciable solubility in the liquid medium i.e. at least 1 percent by weight therein. 71 no, , cadmium, and zirconium compounds are preferred/ The selection of polyvalent metal and the anion ⁷____________ '

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are governed by the solubility of the resultant metal complex or compound, in the liquid medium used.

Examples of the organic and inorganic metal salts and compounds include carboxylic acid salts and chelates, such as zinc acetate,, zinc benzoate,_יtin tartrate, lead acetate, chromium acetate, manganese tartrate, manganese benzoate, magnesium citrate, ferrous acetate, iron lactate, nickel acetate, cobalt acetate, cobalt benzoate, cobalt propionate, copper acetate, chelates or complexes which involve coordination bonding and may be partially ionizable such as the zinc chelate of alanine or glycine, calcium chloride, aluminum diacetate, magnesium acetate, calcium carbonate, zirconium acetate, calcium acetate, calcium hydroxide, barium acetate, magnesium chloride, manganese sulfate, ammonium complexes lj such as of zinc benzoate, zinc carbonate, or zinc sulfate.^

Any salt or chelate having both ionic and coordination bonding in which the metal is sufficiently available or dissociable to bind the carboxyl groups of the polymer is useful,

The ammonia and amine, complexes (and especially those coordinated with NH^) of these metals are particularly useful. Amines capable of so complexing include morpholine, monoethanol amine, diethylaminoethanol, and ethylenediamine, Polyvalent metal complexes (salts) of organic acids that are capable of

2? solubilization in an alkaline pH range may also, be employed.

Such anions as acetate, glutamate, formate, carbonate, salicylate, glycollate, octoate, benzoate, gluconate, oxalate and lactate are satisfactory. Polyvalent metal chelates wherein the ligand is a bidentate. amino acid such as glycine 30 or alanine are particularly preferred. The polyvalent metal compound must be such that the metal is available to serve its crosslinking function, i.e., it is dissociable to some

-pextent to form polyvalent metal-containing ions, or it is attracted to the carboxyl groups by an equivalent mechanism. It is not intended that the invention be limited by these or other theories or hypotheses of the mechanism performed by'the coopera. tion between the metal compound .and the carboxyl groups of the polymer. . Crosslinking as used herein is intended to cover any of the possible phenomena or mechanisms by which the polyvalent metal modifies the adhesive of the invention.

Preferred' polyvalent metal compounds, complexes and chelates include zinc acetate, cadmium acetate, zinc glycinate, cadmium.glycinate, zirconium carbonate, zinc carbonate, cadmium carbonate, zinc benzoate, zinc salicylate, zinc glycollate and cadmium glycollate. Although the polyvalent metal compound may be added to the adhesive composition in dry form such as a powder, 15 it is preferred to first solubilize the polyvalent metal compound ׳ using a fugitive ligand such as ammonia or a volatile amine. For purposes of this invention a ligand is considered fugitive if at least a portion of said ligand tends to volatilize under the film forming conditions utilized. Since the ammonia may complex with the polyvalent metal compound, a compound such as zinc glycinate, when solubilized in dilute aqueous ammonia solution, may be named zinc ammine glycinate or zinc ammonium glycinate.

A group of polyvalent metal complexes employed in adhesive formulations of this invention contain a polyvalent metal

2Jj moiety, an organic bidentate aminoacid ligand moiety and generally, if the chelate is added to the formulation in solubilized form, an alkaline moiety. The polyvalent metal ions may be those named above such as beryllium, cadmium, copper, calcium,.magnesium, zinc, zirconium, barium, strontium, aluminum, bismuth, antimony, lead, cobalt, iron, nickel or

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any other polyvalent metal which can be added to the composition

3¾ an oxide, hydroxide, or basic, acidic, or neutral salt chelate, or complex which has appreciable solubility in the liquid medium,

i.e. at least 1ft by weight therein. The alkaline moiety may be provided by ammonia or an amine. The amino acid bidontate ligand is preferably an aliphatic amino acid, but may also be a heterocyclic amino agid.

The amino acid bidentate ligands may be represented by the formula

X / ^R2 ^OH wherein and R₂ are each hydrogen, alkyl, phenyl or benzyl; R^ represents a straight chain or branched chain alkylene, alkylidene or aralkylidene radical having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and providing a chain of from 1-3 carbon atoms extending between the nitrogen atom and the carbonyl carbon atom;

it being provided that, when R_p is H, R^ and R^ may be joined together to form a 5 or 6 membered heterocyclic ring with the nitrogen atom to which they are attached. Preferred values for Rj and Rg are hydrogen said alkyl radicals containing from 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl and butyl. R-j is preferably methylene, but may also be ethylene, propylene, ethylidene, n-propylidene, isopropylidene, butylidene and phenylethylidene.

Representative bidentate amino acid ligands include glycine (aminoacetic acid), alanine (a-aminopropionic acid), βalanine (β-aminopropipnic acid), valine (a-iso-propylaminoacetic acid)j norvalino .(α-β-propylaminoacetic acid), a-aminobutyric acid, leucine (2-amino-^l1-me׳thyl pentanoic acid), norleucinc λ (2-aminohexanoic acid), N-methylaminoacetic acid, N-0thylaminoacetic acid, dimethylaminoacetic acid,'diethylaminoacetic acid, N-n-propylaminoacetic acid, N-iso-propylaminoacetic acid, Nbutylaminoacetic acid, .phenylalanine, N-phenylarainoacetic acid, . N-benzylaminoacetic acid, proline., nicotinic acid and tetrahydronicotinic acid. .

Preferred polyvalent metal complexes include cadmidm' glycinate, nickel glycinate, zinc glycinate, zirconium glycinate, cobalt alaninate, copper alaninate, zinc alaninate, copper β- ! alaninate, zinc β-alaninate, nickel noryalinate, zinc valinate 1 and copper dime.thylaminoacetate. '. .

The polyvalent metal complexes used in the adhesive comp.osi tion of the invention must be stable in an alkaline solution; however a complex that is too stable is undesirable since dissociation of.the « metal ions would bs retarded during film formation of the coating. !

The polyvalent metal compound used is employed in an

34589/2 ^r amount so that the ratio of polyvalent metal to the carboxyl groups of the α-β-ethylenlcally unsaturated acid or other polymerizable carboxylic acid of the addition polymer is from 0.01 to 2,0, and preferably from 0.05 to 1,5. This is expressed on an equivalency basis as the ratio of metal, such as Zn⁺⁺, to -COOH or -COOHH.

groups, a ratio of 0.5 being stoichiometl^b in the case of a divalent ion. When the polymer is a dispersion or emulsion and the metal is calcium and/or magnesium, the latter may even be supplied in whole or in part by the use of hard water, contrary to the usual practice of making emulsion polymers and formulating them with deionized or distilled water. It is preferred at the higher levels of carboxylic aqid content to use proportionately less polyvalent metal; the proportions are chosen so that the adhesive remains tacky but yfet has good cohesive strength. In some cases excess metal compound has no deleterious effect.

The preferred aqueous dispersion when finally formulated as an adhesive composition should have a pH of 2.0 to 10.0 or more. Most advantageously, its pH is from 6.5 to about 9.5. Suitable alkaline or buffering agents such as borax, sodium hydroxide, ammonia, or amines such as diethylamine, triethylamine, morpholine or triethanolamine may be introduced to adjust the pH to the desired value. At least a portion of the alkaline material must be such that it is volatilized upon drying and heating the adhesive coating 80 that the polyvalent metal ions may perform their ionic crosslinking or equivalent function to link or bind carboxyl groups.

Conventional additives for pressure sensitive adhesives may also be included, for example fillers or pigments, tackifier resins such as wood rosin, and polyester resins, plasticizers such as the alkyl esters of adipic or phthalic acids, antioxidants, solvents suoh as alkanols having 1 to 12 carbon atoms, for example, isopropanol and foam suppressors.

Many types of fillers or pigments may be employed. One of the best is rutile titanium dioxide. Others such as anastaae titanium dioxide, lithopone, magnesium silicate, clay, wollastinite, zlno ok ide, caLcium carbonate, clays including kaolin and bentonite and walnut shellί are also useful. To some extent fibrous fillers such as cellulosic fibers or nylon staple may be employed. These additives are incorporated in the aqueous dispersion, nonaqueous dispersion or solution prior to coating a substrate therewith.

The compositions of this invention may be used to deposit pressure sensitive adhesive coatings on a wide variety Of substrates, .cincluding rigid flexible, non-extensible or stretch able materials including textile fabric, plastic film, nonwoven fiber sheets including water-laid and air-laid products, metal sheets or foil, rubber or synthetic rubber, decorative sheets, plywood edging for plywood sheets and decals. If in a roll, the back of the tape is usually coated with a release, backsize, or adhesive coating, Two sided adhesive articles are also useful. If not coiled into a roll, strippable paper or other protective means is provided. Commonly the face of the backing to which the pressure sensitive adhesive is applied is sized to improve the adhesion of the backing and the adhesive.

The adhesive compositions of the present invention have been found to provide exceptionally good bonds with numerous substrates, including wood, paper, Formica (Registered Trademark) other plastic materials such as methyl methacrylate, polyvinyl chipride, Saran (Registered Trademark), polyethylene glycol terephthalate, nylon, phenolformaldehyde resins, urea-formaldehyde resins, and other thermoset materials such as melamine-formaldehyde resins; rayon, cotton, silk, wool, fibers of the polymeric materials mentioned above, leather, linoleum, asphalt tile, vinyl tile, ceramic tile, various silicates such as glass, mineral wool, asbestos, concrete, asbestos cement, plaster, metals such as aluminum, steal, iron, oopper, zinc, chromium, nickel, an well ao painted or enamelled surfaces, such As painted automobile bodie , woodwork, walls, ceilings, or floors. 'י .

Pre—cemented articles such as tapes, wallpapers, or tiles for decorating walls, floors, or ceilings may be produced in which the member I to be ultimately applied to a surface to be decorated, such as a tape, . j

! ' ׳ ׳ wallpapey, or tile is provided on its back surface with a layer of the composition of the present invention and a protective backing is applied over the adhesive layer and is adapted to be stripped therefrom at the time the member is to be applied to the surface it is. ultimately intended ן for. The protective layer may be a thin film of polyethylene or other j material which can be stepped more or less readily from the adhesive layer. Besides tape, wallpaper,, and tile,, this technique may be used in ; connection with plastics films, wood veneer layers, or thin sheets of .resin or plastic material such as sheets of Formica plastic 01’ vinyl resin;

: films or sheets may be of any size .adapted to be cut to ultimate finishing.of tables, counters,. desks, or other furniture. ,

The pressure sensitive adhesive composition is applied to the substrate or backing by a conventional coating technique and is thereafter dried and heated to effect cross-linking of the polymer.

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In the following Examples, which are illustrative of the invention, the parts and percentages are by weight unless otherwise noted.

Wil 0 tho polymor of tho invention io p^ofegg^^aaqueous dispersion, or an organic solvent^®l^n4a0n prepared in .

those mediums _? it may alsgJse-Tisedand/or prepared as a nonaqueous disjis^ionfa bulk polymerizate, an organic solvent

Solution of the -polymer-emul3ifi-ed in wa-ter, and the like-r Example 1

A glass bottle is charged with 100 grams of distilled tetrafluoroethylene. covered , .

water and a magnetic stirrer bar. The contaner is placed on a magnetic stirring plate, and stirring speed ad10 justed to give a vortex reaching nearly to the bottom of the . liquid. Zinc oxide (22 grams) is sifted into the water and stirred until a well-mixed slurry is obtained. At this point, ¹+0 ml. of 28^ ammonium hydroxide are added, followed by 42 grams of glycine, and stirring continued-until a clear solution is 15 obtained.

A second container is charged with 100 grams of an aqueous dispersion containing 55 weight percent of a tacky acrylic emulsion copolymer prepared in a conventional manner of a 98/2 weight ratio mixture of butyl acrylate and methacrylic 20 acid. The emulsion is stirred using a magnetic stirrer assembly, and zinc ammonium,glycinate solution, prepared as described above, is added in an amount to give about 0.25 equivalents of group .

zinc per carboxyK After mixing for several minutes, an aqueous solution of 1ך<> ammonium hydroxide is added to the emulsion until 25 the pH.is raised to 9*5 as indicated by a Leeds and Northrup

Model'?400-A-2 pH meter.

A film of the resultant emulsion is coated onto a polyethylene terephthalate sheet, using an adjustable Gardner knife set to an 8 mil gap. After standing 2 hours at 25° C., 30 the film is baked 15 minutes at 120° C. to drive off ammonia and accomplish the ionic crosslinking. Following'a 48 hour conditioning at 25° C. and 5θ^ relative humidity, the coated ' ' '16

-Wsheet is cut. into 1 x 8 adhesive tapes. Shear resistance is measured using Pressure Sensitive Tape Council Method No.'7, which determines how long a 1/2 inch by 1 inch section of adhesive tape will support a 1,000 gram weight under standard conditions. Tack is determined by a 5 member test panel using qualitative touch or thumb comparisons. Results are shown in Table I.

Example 2

An acrylic emulsion copolymer based on 98 weight percent butyl acrylate and 2 weight percent methacrylic acid is treated with half the amount of zinc glycinate as the product described in Example 1, and pH is raised to 9. 5. Mixing techniques are identical to those described above. Test samples are prepared and evaluated using the same methods as those used in studying the product of־ ־Example 1. Data are shown on Table I.

<td> 15</td><td></td><td> Table I</td><td></td><td></td>

<td></td><td> Sample</td><td> Equiv. Zinc per -COOH</td><td> Shear Resistance</td><td> Tack</td>

<td></td><td> Product from.Example 1</td><td> 0.25</td><td> 7 hours</td><td> Excellent</td>

<td></td><td> Product from Example 2</td><td> 0.12?</td><td> 6 hours</td><td> Excellent</td>

<td> 20</td><td> Unmodified 98 BA/2 MAA* Copolymer</td><td> . None</td><td> 0.9 hours</td><td> Excellent</td>

*BA = butyl acrylate

MAA = methacrylic acid

Example ^fAn adhosivo prepared׳ as in׳ Example 1 but containing^anemulsion polymer prepared from 80 parts isobut^-aeiyiate, 10 parts methyl methacrylate and tenga^4s^acrylic acid, and zirconium acetate in an amount to^grVea Zr++ to -COOH or -COONH^ ratio on an equival^xtt-s'TSasis of .1, is applied to polyvinyl chloride film artidoured as in Example 1, with similar—results.

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EXAMPLE 3

Repeating Example® 1 and 2 but using zinc alaninate and zirconium alaninate as the metal compound gives similar results, Any of the soluble or solubilized metal compounds disclosed above are also useful.