CA2108491A1

CA2108491A1 - Quick-set non-cementitious adhesive

Info

Publication number: CA2108491A1
Application number: CA002108491A
Authority: CA
Inventors: Xiaohong Ci
Original assignee: Individual
Current assignee: Rohm and Haas Co
Priority date: 1992-10-23
Filing date: 1993-10-15
Publication date: 1994-04-24
Also published as: BR9304248A; JP3292258B2; CN1086241A; KR940009310A; MX9306398A; JPH06316691A; ZA937537B

Abstract

ABSTRACT OF THE DISCLOSURE:

This invention solves the problems encountered with conventional cementitious and non-cementitious adhesives by providing an aqueous, quick-set noncementitious composition which is easily applied, develops early cohesive strength and leaves no waste under all curing conditions. The invention is particularly useful as an adhesive used in exterior insulating and finishing systems. This invention also provides a method for improving the early cohesive strength of a non-cementitious adhesive under all curing conditions.

The aqueous, quick-set, non-cementitious composition of this invention requires three components:
(1) a film-forming latex polymer having anionic character;
(2) an amine-containing polymer formed from at least 20% by weight monomer containing amine functional groups;
and (3) a volatile base.

The method for improving the early cohesive strength of a non-cementitious adhesive under all curing conditions involves:
(1) forming an non-cementitious adhesive containing:
(a) a film-forming latex polymer having anionic character;
(b) an amine-containing polymer formed from at least 20% by weight monomer having amine functional groups; and (c) a volatile base;
(2) applying the non-cementitious adhesive to the exterior surface of a building or other outdoor structure; and (3) applying a solid or foamed layer of protective material to the non-cementitious adhesive.

Description

21,0~3~9 QUICK SET NON~CEME~ITl~OUS ADHE~;IVE

FIEI~ OF THE INVENlION

This invention relates to a aqueous, quick-set, non-cementitious adhesive which provides early cohesive and adhesive strength and to a method for improving the early cohesive and adhesive strength of non-cementitious adhesives.

BACKGROUND OF THE INVENIION

Exterior insulation and finishing systems ("EIFS") are multilayered composite sy6tems installed on the outsides of buildings and other outdoor structures to insulate, protect and beautify. The exterior surface of the building or other outdoor structure may be constructed of concrete, cinder block, stone, brick, wood, gypsum board and the like. A layer of material, typically in the form of a solid or foamed sheet of material such as for example foamed and extruded polystyrene, is applied to the exterior surface of the building or other outdoor structure and is covered with a mesh-reinforced basecoat and then a topcoat. If a mechanical fastening means is not used, an adhesive is needed to bond the layer of material to the exterior surface of the building or other outdoor structure. The adhesive may or may not contain cement. Problems are encolmtered both with adhesives which contain cement and adhesives which do not contain cement.

Calcium oxide, silica, alumina and iron oxide, in appropriate proportions, chemically combine at high temperatures to form a composite of hydraulic cement. When the hydraulic cement is contacted with water, its constituents begin to hydrate and to set into a hard substance typically on the order of one to three hours. This leaves only a short pot life for the application of adhesives which 21~91 contain cement while they are still fluid. Contractors using a cement-containing adhesive must discard any unused material because it will not be usable after setting into a hard substance, usually in less than about five hours. This leads to considerable waste.

This waste problem may be avoided by using non-cementitious adhesives. However, conventional non-cementitious adhesives have experienced poor early adhesive and early cohesive problems because they lack the adhesive and cohesive strength provided by the cement.
This drying time may be several days depending upon the environmental conditions. The problem is further exacerbated because the layer of material applied to the exterior surface of a building or other outdoor structure is typically a hydrophobic material, such as polystyrene fioam, which impedes the movement of water out of the layered exterior finishing system. Until the layered exterior finishing system sets, the adhesive does not have sufficient cohesive and adhesive strength to bond the layer of material to the exterior surface of a building or other outdoor structure. This is particularly a problem in areas where the materials might be disturbed or where the weather is cold and wet or humid.

It is an object of the present invention to provide a non-cementitious adhesive composition which is easily applied, prnvides early cohesive and adhesive strength under all curing conditions andleaves no waste.

It is a further object of the present invention to provide a method for improving the early cohesive and adhesive strength under all curing conditions of a non-cementitious adhesive.

SU~IARY OF THE INVENTION

~...... i, . ~, -, ., , . . , "". ,, , . - , . - ~ ,.. , . .-.................... . , .... ~ .. : .. : .
1~,: ' ' . ': ' . . :,, . ~ . ,~ : ' , ., ' ;~ ~

2~ ~8~9~

This invention solves the problems encountered with conventional cementitious and non-cementitious adhesives by providing an aqueous, quick-set noncementitious composition which is easily applied, develops early cohesive and adhesive strength under all curing conditons and leaves no waste. The invention is particularly useful as an adhesive used in exterior insulating finishing systems. This invention also provides a method for improving the early adhesive and cohesive strength under all curing conditions of a non-cementitious adhesive.

The aqueous, quick-set, non-cementitious composition of this invention requires three components:
(1) a film-folming latex polymer having anionic character;
(2) an amine-containing polymer formed from at least 20%
byweight monomer containing amine functional groups;
and (3) a volatile base.

The method for improving the early adhesive and cohesive ;
strength of a non-cementitious adhesive under all curing conditions involves: ~:
(1) forming an non-cementitious adhesive containing: -(a) a film-forming latex polymer having anionic character~, (b) an amine-containing polymer; and -~
(c) a volatile base;
(2) apply-ing the non-cementitious adhesive to the exterior surface of a building or other outdoor structure; and (3) applying a solid or foamed layer of protective material to the non-cementitious adhesive.

;S,:."" : . ' . .

,. 2las~s~
':'~
DETADLED DESCRIPIION OF T~ INVENTION

The aqueous adhesive composition of the present invention requires:
(1) a film-forming latex polymer having anionic character;
(2) an amine-containing polymer; and (3) a volatile base.
The aqueous adhesive composition of the present invention is "non-cementitious" which, as used herein, means that the composition is completely free of cement.

The aqueous adhesive composition of the present invention provides early adhesive and cohesive strength under all curing conditions. As used herein, the term "early" refers to the period when the adhesive is still wet. "Cohesive strength," as used herein refers to the attractive force a material has for itself. "Adhesive strength," as used herein refers to the attractive force a material has for a substrate and to the strength to bond surfaces together. The most stringent curing conditions ~or the aqueous adhesive composition of the present invention are cool and damp conditions.

"Glass transition temperature," or "Tg," as used herein means the glass transition temperature of a polymer as calculated by the Fo~ equation [Bulletin of A.~2içan P~y~ So~iet~ 1, 3, ~age 12;
(1956)]:

1 _ = w~_ ~ w~7.
Tg Tg(l) Tg(2) J
21~9 l.
For a copolymer, wl and w2 refer to the weight fraction of the two comonomers and Tg(l) and Tg(2) refer to the glass transition temperatures of the two corresponding homopolymers.

FILMFORMING: LATEX~P~I~YMER

The aqueous adhesive composition of the present invention requires a film-forming latex polymer having anionic character.
"Latex" as used herein refers to a water-insoluble polymer which may be prepared by conventional polymerization techniques such as, for example, by emulsion polymerization. The latex polymer is formed from any monomer or mixture of monomers w~ich yields a water-insoluble latex polymer which will form a f;lm under the application conditions.
- . . . :.
The Tg of the latex polymer is limited only by the particular application for which the adhesive composition is to be used. For example, if the adhesive is to be applied outdoors in hot summler weather, then the composition of latex polymer may be selected to yield a Tg greater than if the adhesive is to be applied outdoors in cold winter weather. Generally, the latex polymer has a Tg from about ~
50C to about 50C. A coating containing a latex polymer having a Tg below -50C is generally not useful since it is too soft and lack sufficient strength to act as an adhesive. A coating containing a latex polymer having a Tg above 50C is generally not useful since it is too hard to form a film even at higher than ambient temperatures.
Polymers having a Tg from about -1~C to about 10C are preferred.
Polymers having a Tg from about -10C to about 5C are most preferred.

The invention may also be practiced using polymers of more complex morphology, such as core-shell particles. These complex .. , i .. . :. . . , j ,. ~ ~, 2~8~
~ ~ `
polymer morphologies usually display multiple Tg's and may display a Tg value outside the range of from about -50C to about 60C as one of its multiple Tg 's, however the average or effective Tg of the polymer must be from about -50C to about 50C.

The anionic character of the f~llm-forming latex polymer is obtained in any of several ways, the most common being the use of anionic surfactants or dispersants as the stabilizer during the emulsion polymerization or added to the emulsion after polymerization. Nonionic surfactants may also be present in the latex during or after polymerization of these anionically stabilized latexes. Among the useful surfactants and dispersants are the salts of fatty rosin and naphthenic acids, condensation products of napthalene sulfonic acid and formaldehyde of low molecular weight, carbo~ylic polymers and copolymers of the appropriate hydrophile-lipophile balance, higher alkyl sulfates, such as sodium lauryl sulfate, alkyl aryl sulfonates, such as dodecylbenzene sulfonate, sodium or potassium isopropylbenzene sul~onates or isopropylnaphthalene sulfonates; sulfosuccinates, such as sodium dioctylsulfosuccinate alkali metal higher alkyl sulfosuccinates, e.g sodium octyl sulfosuccinate, sodium N-methyl-N-palmitoyltaurate, sodium oleyl isethionate, alkali metal salts of alkylarylpolyetho~yethanol sulfates or sulfonates, e.g.. sodium t-octylphenoxy-polyethoxyethyl sulfate having 1 to 5 oxyethylene units, and the various other anionic sur~actants and ~ispersan~Gs well-known in the art.

Another type of latex polymer having anionic character is that which is obtained as a result of including in the polymer small amounts of acidic groups, which may be in the salt form, such as an alkali metal or ammonium salt. Examples of such acidic groups are those derived from incorporated initiator fragments, maleic acid, ` ~ 2108~
vinyl sulfonic acid, crotonic acid, acrylic acid, methacrylic acid, itaconic acid, and the like.

A third useful type of latex polymer having anionic character is a latex polymer which includes a basic monomer which has been neutralized, such as for example acrylamide, methacrylamide and the like.

The latex polymer may have more than one type of anionic character : .. , ~, -~:, The latex polymer having anionic character can be prepared by known procedures, which are published in texts on the subject such as Emulsion Polvmerization: 'rheorv and Practice by D. C. Blackley published by Wiley in 1975 and Emulsion Polymerization by F. A
Bovey et al. published by Inter~cience Publishers in 1965. In general, the latex polymer is a polymer or copolymer prepared from monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, 2 ethylhexyl acrylate, decyl acryate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, styrene, butadiene, ethylene, vinyl acetate, vinyl ester of '~ersatic" acid (a tertiary monocarboxylic acid having Cg, Clo and Cll chain length, the vinyl ester is al~o known as "vinyl versatate"), vinyl chloride, vinyl pyridine, vinylidene chlolide, acrylonitrile, chloroprene, acrylic acid, methacrylic acid, itaconic acid, maleic acid and fi~aric acid. Polymers and copolyme~
ethylenically unsaturated monomers and their esters, especially the acrylic and methacrylic esters, are preferred and are preferably prepared by processes given in "Emulsion Polymerization of Acrylic Monomers:
May, 1966" published by the Rohm and Haas Company, Philadelphia, Pennsylvania, incorporated herein by reference.

:
2iO8~9~
AMINE-CONTAININ& POLYMER .~ .

The aqueous adhesive of the present invention requires an :
amine-containing polymer which has been formed from at least 20% by weight of a monomer which contains amine functional groups. A
polymer having at least 50% by weight of monomer containing amine functional groups is preferred. It is also preferable that the average molecular weight of the water-soluble or water-dispersible amine-containing polymer is from about 5,000 to about 100,000. -The examples of monomer containing amine functional groups include the following: ;

1. Aminoalkyl vinyl ethers or sulfides wherein the alkyl groups may be straight-chain or branched-chain type and have from two to three carbon atoms and wherein the nitrogen atom may be a primary, secondary, or tertiary nitrogen atom (U.S. Patent 2,879,178). In the latter instance, one of the remaining hydrogen atoms may be substituted by alkyl, hydroxyalkyl, or alkoxyalkyl groups, the alkyl components of which may have one to four carbon atoms, preferably one carbon atom only.

Specific examp~es inc1ude: ~-am;noe~yl v;nyl e~er;
,B-aminoethyl vinyl sulfide; N-monomethyl-b-aminoethyl vinyl ether or sulfide; N-m~noethyl-,B-aminoethyl vinyl ether or sulfide;
N-monobutyl-,B-aminoethyl vinyl ether or sulfide; and N-mono-methyl-3-aminopropyl vinyl ether or sulfide.

21~8~9~
. , `............................................................. .
2. Acrylamide or acrylic esters, such as those of the formula II~

H~C= C~R~ X}n A--I~IR RO
wherein R is H or CH3;
n is O or l;
X is O or N(H); ~ .
When n is zero, A is O(CH2) x wherein x is 2 to 3, or (O-alkylene) y wherein (O-alkylene)y is a poly(oxyalkylene) group, having a molecular weight in the range from 88 to 348, in which the individual alkylene radicals are the same or different and are either ethylene or propylene;
and :~
..... . .
when n is 1, A is an alkylene group having two to 4 carbon atoms;
R* is H, methyl, or ethyl; and :- -R1 IS H, methyl, or ethyl; and R is H, phenyl, benzyl, methylbenzyl, cyclohexyl, or (Cl-C6) alkyl. -Examples of compounds of formula II include~
dimethylaminoethylacrylate vr methacrylate; ,B-aminoethyl acry~ate ar ~ ;
methacrylate; N-,B-aminoethyl acrylamide or methacrylamide;
N-(monomethylaminoethyl)-acrylamide or methacrylamide; . :-N-(mono-n-butyl) 4-aminobutyl acrylate or methacrylate;
methacryloxyethoxy ethylamine; and acryloxypropoxypropylamine.

3. N-acryloxyalkyl-oxazolidines and N-acryloxyalkyl tetrahydro-1,3-oxazines and the corresponding components in which -- 2 1 ~ 8 4 ~
; ~ the "alkyl" linkage is replaced by alkoxyalkyl and poly(alkoxy-alkyl), all of which are embraced by Formula III~
/~H2m H~C= c~R~e--A' IY /
\ C

wherein ~:
R is H or CH3;
m is an integer having a value of 2 to 3;
R', when not directly joined to R2, is selected from the group -consisting of hydrogen, phenyl, benzyl, and (Cl-Cl2) alkyl groups;
R2, when not directly joined to R', is selected from the group consisting of hydrogen and (Cl-C4) alkyl groups;
R'and R2, when directly joined together, form a 5- to 6-carbon ring with the attached carbon atom of the ring in the formula, i.e., R'and R2, when joined together, are selected from the group consisting of pentamethylene and tetramethylene; and A' is O(CmH2m)- or (O-alkylene)n in which (O-alkylene)nis a poly(oxyalkylene) group, having a molecular weight in the range from 88 to 348, in which the individual alkylene radicals are the same or different and are either ethylene or propylene.

The compounds of Formula III can hydrolyze under various conditions to secondary amines. The hydrolysis produces products having the Formula IV:
' ., - .
H~C--C~R~e--A--hl~H~--~CmH2m~--OH (IV) , '' . ~., :. .~ . .
. . .

2 1 ~ 8 4 ~
: "~
The compounds of Formula III are disclosed in U.S. Patents 3,037,006 - -and 3,502,627 in the hands of a common assignee, and their corresponding foreign applications and patents and any of the ~`
monomeric compounds disclosed therein may be used in making the ~ -copolymers to be used in the composition of the present invention.
Examples of compounds of Forrnula III include~
oxazolidinylethyl methacrylate; ~-oxazolidinylethyl acrylate;
3-(~-methacryl-oxypropyl)-tetrahydro-1,3-oxazine;
3-(~-methacryloxyethyl)-2,2-pentamethylene-oxazolidine;
3-~-methacryloxyethyl-2 methyl-2-propyloxazolidine; ;~ -N-2-(2-acryloxyethoxy)ethyl-oxazolidine;
- N-2-(2-methacryloxyethoxy)ethyl-oxazolidine;
N-2-(2-methacryloxyethoxy)ethyl-5-methyl-oxazolidine;
N-2-(2-acryloxyethoxy)ethyl-5-methyl-oxazolidine;
3-[2-(2-methacryloxyethoxy)ethyl)]-2,2-penta-methylene-oxazolidine;
3-[2-(2-methacryloxyethoxy)ethyl)]-2,2-dimethyl-oxazolidine;
3-[2-(methacryloxyethoxy)ethyl]-2-phenyl-oxazolidine.

4. Polymers of monomers which readily generate amines by hydrolysis are useful as the amine-containing component or to generate the amine-containing component polymer of this binder composition. Examples of such monomers are acryloxy-ketimines and -aldimines, such as those of Formulas V and VI following:

H2C=(CR)-COOA"N=Q (V) :
11 ~ '''"~

-~` 21~8~9~
.~ ,:,, H2C = C(R)-CO-(D)n 1 - (B)n l - (A)n I - N = Q (VI) wherein .
RisHorCH3;
Q is selected from the group consisting of R
\R5 =IC ~CHR }xl 3 ~-R6 is H or it may be methyl in one CHRfi unit;
R5 is selected from the group consisting of (Cl-CI2)-alkyl and cyclohexyl groups;
R4 is selected from the group consisting of (Cl-Cl2)-alkyl and cyclohexyl;
R3 is selected from the group consisting of phenyl, halophenyl, (Cl-CI2)-aLlcyl, cyclohexyl, and (Cl-C4) alkoxyphenyl groups;
A" is a (Cl-CI2) alkylene group;
A, B and D are the same or different oxyalkylene groups having the formula -OCH(R7 )-CH(R7 )-wherein R7 is H, CH3, or C2Hs;
x is an integer having a value of 4 to 5;
no is an integer having a value of 1 to 200;
n' is an integer having a value of 1 to 200; and n" is an integer having a value of 1 to 200, the sum oE n-l, n'-l and n"-l having a value of 2 to 200. -~
; ~ .
Illustrative compounds of formulas V and VI are:
2-[4-(2,6-dimethylheptylidene)-amino]-ethylmethacrylate; ~ :
3-[2-(4-methylpentylidine)-amino~-propyl methacrylate; - ;
~-(benzylideneamino)-ethyl methacrylate;
3-[2-(4-methylpentylidene)-amino]-ethylmethacrylate;

21~8~9~
~., 2-[4-(2,6-dimethylheptylidene)-amino]-ethyl acrylate;
12-(cyclopentylidene-amino)-dodecylmethacrylate; ~ -:
N-(1,3-dimethylbutylidene)-2-(2-methacryloxyethoxy)-ethylamine;
N-(benzylidene)-methacryloxyethoxyethylamine;
N-(1,3-dimethylbutylidene)-2-(2-acryloxyethoxy)-ethylamine;
N-(benzylidene)-2-(2-acryloxyethoxy)ethylamine.

The compounds of Formulas V and VI hydrolyze in acid, neutral, or alkaline aqueous media to produce the corresponding primary amines or salts thereof in which the group -N = Q of the formulas becomes -NH2 and O = Q. The compounds of Formulas V and VI are disclosed in U.S. Patents 3,037,969 and 3,497,485, and any of the -monomeric compounds therein disclosed may be used in the making of the copolymers to be used in the water-soluble polymer portion of the compositions of the present invention.

The preferred class of amine-containing polymers of this invention are water-soluble. By water-solubility is meant that the polymer is completely soluble either in free-base, neutral, or salt form.
The solubility preferably exists at all pH's, especially in the range of about 4 to 10. A less preferred class of water-soluble amine-containing polymers are generally insoluble at high pH and soluble or partly soluble at acidic pH values, particularly in the p~ range from about about 7. By partly soluble is meant both the situation in which some of the polymer is so!uble in water as well as that in which the entire polymer dissolves in the form of micelles or aggregates individual molecules, generally, highly water swollen aggregates. The latter are often called colloidal solutions. It is preferred that most of the polymer be soluble at the acidic pH values. The water-soluble amine-containing polymers of this invention include both the completely soluble and the -:

21~8~9~ :
. . .
partly soluble polymers as described immediately above.

A useful but still less preferred class of amine-containing polymers are those which are water-insoluble and, as will be noted below, have a molecular weight corresponding to the lower end of the range for the water-soluble counterparts. These water-insoluble amine-containing polymers perform the same function as the water-soluble polymers. When these water-insoluble polymers are substituted for the water-soluble polymers, the early cohesive strength of the anionically stabilized latex polymer is improved; however, the improvement is usually not as great as that produced by the water-soluble polymers.

In general, the amine-containing polymers of at least 20% by weight of a monomer of categories 1, 2, 3, and 4, supra, may be obtained by solution polymeri~ation in aqueous media, either neutral, alkaline, or acidic, depending upon the particular polymer sought. Generally, the polymerization is carried out in an aqueous medium containing a small amount of an acid, either organic or inorganic, such as acetic acid or hydrochloric acid. The amine-containing polymers include copolymers with up to 80% by weight one or more such as methyl acrylate, acrylamide, methacrylamide, and quaternary ammonium salts derived from the amine monomers, such as 2-methacryloxyeth~
trimethyl ammonium chloride. Small amounts of relatively insoluble comonomers may also be used to obtain the water-soluble polymers The insoluble polymers may contain larger amounts of these comonomers. Such monomers include, as examples, acrylic acid esters with (Cl-CIg) alcohols and methacrylic acid esters with alcohols having one to 18 carbon atoms, especially (Cl-C4) alkanols; styrene, vinyltoluene, vinyl acetate, vinyl chloride, vinylidene chloride, ~; '"" '~ "'. ,'''. '",,"'''" .' ' " ""'' ';

21~91 : ~ ~
"1"
substituted styrenes, butadiene, substituted butadienes, ethylene; and the nitriles and amides of acrylic or of methacrylic acid. The particular comonomer or comonomers used in making a given amine-containing polymer depends upon the proportion of amine-containing monomer used in making the copolymer.
Preferably, a comonomer with relatively high solubility in water is exclusively used to make the water-soluble polymers. The polymers are thus polymers or copolymers of cationic and, optionally, nonionic vinyl monomers. Examples of the cationic monomers are the amines, imines and quaternary ammonium salts; the other recited monomers are nonionic. Thus, these water-soluble copolymers contain no acid groups other than trace amounts which may be present due to impurities in the monomers used or to small extent of hydrolysis during synthesis, storage or use.

The insoluble amine-containing polymers have a viscosity average molecular weight from about 5,000 to about 100,000, with the range of from about 15,000 to about 90,000 preferred. The molecular weight of the water-soluble polymers may fall within a wide range;
, typically, the viscosity average molecular weight is from about 5,000 to about 300,000, with the range of from about 40,000 to about 100,000 preferred. The amount of the amine-containing polymer may range from about 0.1% to about 20% by weight of the total weight of anion~
latex polymer and amine-containing polymer, the range from 0.5% to 8% being preferred.

Water-soluble amine-containing polymers include both the completely soluble and the partly soluble polymers. The term water-soluble amine-containing polymer describes polymer that is completely soluble either in free-base, neutral, or salt form. Some 21 D 8~9~
polymers are soluble at all pH's, while others are soluble over a range of pH for example from about 5 to 10. Other amine-containing polymers are generally insoluble at high pH and soluble or partly soluble at acidic pH values, particularly in the pH range from about 5 to about 7. By partly soluble is meant both the situation in which some of the polymer is soluble in water as well as that in which the entire polymer dissolves in the form of micelles or aggregates of individual molecules, generally, highly water swollen aggregates. The latter are often called colloidal solutions. It is preferred that most of the polymer be soluble at the acidic pH values.

In general, the amine-containing polymers may be obtained by solution polymerization in aqueous media, either neutral, alkaline, or acidic, depending upon the particular polymer sought, as generally known in the art, for example as taught in U.S. Patent 4,119,600 Generally, the polymerization is carried out in an aqueous medium containing a small amount of an acid, either organic or inorganic, such as acetic acid or hydrochloric acid. The amine-containing polymers include copolymers with up to 80% by weight one or more monoethylenically unsaturated monomers, such as methyl acrylate, acrylamide and methacrylamide. Small amounts of relatively insoluble comonomers may also be used to obtain the water-soluble polymers. The insoluble polymers may contain larger amoun~cs ~f these comonomers. Such monomers include, as examples, acrylic acid esters with (Cl-Clg) alcohols and methacrylic acid esters with alcohols having one to 18 carbon atoms, especially (Cl~4) alkanols; styrene, vinyltoluene, vinyl acetate, vinyl chloride, vinylidene chloride, substituted styrenes, butadiene, substituted butadienes, ethylene; and the nitriles and amides of acrylic or of methacrylic acid. The particular comonomer or comonomers used in making a given ~108~9~
. ~,. `;
amine-containing polymer depends upon the proportion of amine-containing monomer used in making the copolymer. The polymers are thus polymers or copolymers of cationic and, optionally, nonionic vinyl monomers. Examples of the cationic monomers are the amines and imines; the other recited monomers are nonionic.
Thus, these water-soluble copolymers contain no acid groups other than trace amounts which may be present due to impurities in the monomers used or to small extent of hydrolysis during synthesis, storage or use.

VOLATILE BASE

The adhesive composition of this invention requires a volatile base. The type and amount of volatile base used must be sufficient to raise the pH of the composition to about the point where the amine functional groups of the amine-containing polymer are non-ionized (deprotonated), typically to at least pH 5, preferably from pH 7 to pH 9, to avoid interaction with the anionically stabilized latex polymer and other anionic components in the adhesive composition.

A starting point estimate of the amount of volatile base required to reach this point can be calculated from the number of equivalents of base needed to neutralize all of the acid groups in the latex (i.~
groups from: copolymerized carboxylic-bearing monomer; surfactant;
or initiator) and the conjugate acid of the amine base. If the amine is not sufficiently deprotonated, the emulsion will exhibit observeable signs of instability over time, such as viscosity increase and microscopically observeable "particle rafting," an early stage of aggregation/gellation. One equivalent of volatile base (based on latex acids and polyamine titers) is usually enough to yield a stable system , : : :, ~ . ., - ~ . . . : :

2~8~
although higher levels of volatile base (~3 to 4 equivalents) may be necessary for long term stability. Higher amounts of volatile base can be used without departing from the spirit of the invention although the "quick dry" properties of the coating may be reduced. If the equipment used in the process of manufacture presents opportunities for loss of the volatile base by evaporation at any stage from when the volatile base is added until after the product is packaged in a sealed container, the amount of volatile amine loaded to the production equipment should be increased to offset the loss.

After application, the volatile base evaporates lowering the pH
of the composition. When the pH of the composition falls to a point where the protonation of the amine functional group begins to occur, the amine functional group becomes cationic. The quick dry is believed to be initiated by this conversion of the amine functional group to a cationic state in the presence of the anionically stabilized emulsion polymer, although the exact mechanism that produces the quick~dry property has not been established and I do not wish to bound by the theory of the exact mechanism.

Suitable volatile bases include but are not limited to ammonia, morpholine, alkyl amines, 2-dimethylaminoethanol, N-methylmorpholine, ethylenediamine, and mixtures ther~of.
Ammonia is preferred.

MULTIVALENT METAL

The aqueous quick-set, non-cementitious adhesive may optionally contain a water-soluble or water-dispersible multivalent metal in the form of a metal ion, salt, complex or oxide. Multivalent 21~8~
metal ions such as calcium, magnesium, zinc, barium, strontium, aluminum and the like may be used. Complexes of multivalent nnetal ions, such as zinc hexammonia, zinc ammonium bicarbonate and the like, and salts of multivalent metal ions with counterions, such as chloride, acetate, bicarbonate and the like, may be used. Zinc is the preferred multivalent metal.

The multivalent metal ion, salt, complex or oxide is useful at a level of from about 0.5% by weight to about 10% by weight, based on the weight of the latex polymer solids. A level of from about 1% by weight to about 7% by weight, based on the weight of the latex polymer solids, is preferred.
:
In addition, conventional adhesive components such as, for example, pigments, binders, vehicles, extenders, dispersants, surfactants, coalescents, wetting agents, rheology modifiers, thickeners, drying retarders, antifoaming agents, colorants, waxes, preservatives, heat stabilizers, solvents, anti-skinning agents, driers and the like may be used in this invention.

Care must be exercised when selecting the type and amount of additives to avoid altering the pH of the composition to an extent that interferes with storage stability or buffering the p~I to an extent ~ha~t after application the pH does not fall sufficiently to initiate protonation of the polyamine. For example an adhesive prepared using a polyamine with a relatively low pKa and too large an amount of calcium carbonate as filler, may display an unacceptably extended cure time.

The adhesive compositions of the invention typically have a Y.~,i'f : : , - . ~ , - -, 21~8~
solids content in the range of from about 10% by weight to about 75%
by weight and a viscosity of from about 50,000 centipoises to about 300,000 centipoises.

The adhesive compositions of the present invention are useful in any type of construction adhesive application where early adhesive and cohesive strength is needed, such as for example, EIFS; cove base; -- floor tile including vinyl, ceramic, and wood; plywood and the like.

The method of the present invention is useful for improving the early cohesive strength of a non-cementitious adhesive. The method involves:
(1) forming an non-cementitious adhesive containing:
(a) a film-forming latex polymer having anionic character; ~ `
(b) an amine-containing polymer formed from at least 20% by weight monomer containing amine functional groups; and (c) a volatile base;
- (2) applying the non-cementitious adhesive to the exterior surface of a building or other outdoor structure; and (3) applying a solid or foamed layer of protective material to the non-cementitious adh~s~.

The building and other structures may be formed from concrete, cement, brick, cinder block, wood, gypsum board, particle board and the like.

, .
The solid or foamed layer of protective material may be foamed polystyrene sheet and the like.

ao 210~49:1 The following examples illustrate some aspects of the invention and should not be construed as limiting the scope of the invention which is described in the specification and claims.

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21~8~9~
EXAMPLE 1. PREPARATION OF ADHESIVE FORMULATIONS .

The adhesives were prepared according to the following formulation by grinding together the ingredients listed as grind . .
ingredients in Table 1.1 and then adding the remaining letdown ingredients for each adhesive formulation. All quantities listed are in grams. :
Table 1.1 Cornparative Adhcshvc Adhcshve ~ -Adhcsive1 1 2 :
- : -Anionicaily stabilized 330.7 330.7 330.7 Latex Polymer (Rhoplex~D AC-264 latex ) (60% solids) Ammonium hydToxide (28%) 5 5 5 Polyoxazolidinylethyl 0 4 4 methacrylate (25% solids) Zinc oxide o O 100 Caicium carbonate 100 100 0 Anionic dispersant 2.5 2.5 2.5 (Tamol 0 850 dispersant) (30% total solids) Potassium tripolyphosphate 1.5 1.5 1.5 Ethylene glycol 2 2 2 Texanol~lD coalescent 2 2 2 (2,2,4-trimethyl-3-hydroxypentyl acetate) Antifoaming agent 4 4 4 (Nopco(iD NXZ antifoamer) Ciay liTier T5 15 ~5 Marble dust 400 400 400 .
Sand a70 400 400 400 -Water 20 20 20 Hydroxyethyl cellulose 0,3 0.3 Q3 (Natrasol0 HR thickener) 21 Q~491 , EXAMPLE 2. SET TIME

The adhesive formulations were tested to determine how long they took to completely set. The test specimens were prepared by casting each adhesive formulation on Teflon~-coated glass at a thickness of from about 1/32 inch to about 1/16 inch.

Testing was done at a temperature of 72F and relative humidity of 32.8%. A Gardner Set Time Recorder was then placed on each freshly made test specimen. The probe on the recorder moves at one revolution per hour through or on top of the adhesive. Set time is reported in minutes and was established when the probe completely moved on the surface of the adhesive without making any trace mark on the surface. Short set times are desirable because they indicate that the adhesive builds early cohesive and adhesive strength. The results are reported in Table 2.1.
Table 2.1 Adhesive Set Time ~::
(minutes) Comparative 1 85 2 35 ~ :-The set time decreased by 25 minutes for the adhesive formulation made according to the invention (Adhesive 1). The set time decreased by a total of 50 minutes for the adhesive formulation made according to the invention which optionally contained :~
multivalent metal (Adhesive 2 -- contained zinc oxide).

23 :

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EXAMPLE 3. TENSILE STRENGTH TESTING

The adhesive formulations were tested for early tensile bond strength under a variety of curing conditions to demonstrate that the aqueous adhesiv~ compositions of the invention showed improved properties under all curing conditions.

In a pre-equilibration chamber, samples were prepared by using a two-part epoxy to glue circular pieces of expanded polystyrene foam (1 inch thick) to a wood disk (2.25 inch dia;meter; 0.5 inch thick). In a like manner, plywood was also glued to a second wood disk. A layer of each adhesive formulation was applied onto the plywood surface of the second wood disk using a spatula and then polystyrene side of the first wood disk was firmly pressed against the layer of adhesive. Each sample was then cured.

Before testing, all samples were equilibrated to test conditions.
The sample was then placed in the Jaws of an Instron testing machine with the sample being pulled apart at an angle perpendicular to the layer of adhesive. All samples were tested at a crosshead speed of 0.5 inches/minute. Tensile strength was reported in pounds per square inch as the ratio of the load at break from the Instron (pounds) to the surface area of the test specimen (square inches). The results a~
reported in Table 3.1. High tensile strengths at break are desirable. In addition, substrate failure (polystyrene) types are more desirable than ~ -adhesive failure types.

24 :

;~ ~

2.1V~9 Table 3.1 Comparative Adhesi~te Adhesive - --Adhesive i 1 2 ~ : :
` '~
TensUe strength at break 20.1 25~3 34.4 (pounds/square inch) Cured at ambi~nt corudilio~ls for 4 hours Tested al 75F arud 50% relahue humidily -- warm Thick~tess of adhesnve = 1/32 U~ch ' ' ;,::
TensUestrengthatbn~.ak 3.4 7~5 13`6 ~poundslsquare inch) Cured at ambienl co~lditio~ls for 3 hours , -Tested at 75F a~ud 50% relative humidity -- warm Thickness of adhesive . 1/8 hlch '' ~ ~'.'' Tensilestrengthatbn.ak 16.6 19.0 29~5 ::
(poundslsquare inch) FaUure qpe 100% adhesive 90% adhesive 100% substrate .
failure failure/10% fallure substrate failure NO'rES:
Cured at ambient conditions for 2 hours Tested at 75F a-uJ 50% relative humidity -- warm Reporied as average of S measurcmenis Thickness of adhesive = 1/16 inch :

TensUe strength at bn.ak 7.16 31.4 34 9 (pounds/squarein h) FaUureqpe 70%adhesive 100%substrate 100%substrate failure/30% failure fallure :
substrate fallure Cured at 82F and 945% relative humidity for 5 hours -- warm and very humid Tested af 75F and 50% relatnve humidity -- warm ' Reported as mverage of S measuremenls ' Thickness of edhesive ~1/16 inch : ;

: ': ;

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The tensile strength increased at both thicknesses for the adhesive formulation made according to the invention (Adhesive 1) as compared to the the adhesive which did not contain an amine-containing polymer (Comparative Adhesive 1). The tensile strength increased even more at both thicknesses for the adhesive formulation made according to the invention which optionally contained multivalent metal (Adhesive 2 -- contained zinc oxide).

The tensile strength increased for the adhesive formulation made according to the invention (Adhesive 1) as compared to the the adhesive which did not contain an amine-containing polymer (Comparative Adhesive 1) under warm conditions and very humid conditions. The tensile strength increased even more for the adhesive formulation made according to the invention which optionally contained multivalent metal (Adhesive 2 -- contained zinc oxide) under warm conditions and under wet and very humid conditions.
Under warm conditions, the adhesive which optionally contained the zinc oxide experienced a desirable 100% substrate failure (Adhesive 2) and the comparative adhesive experienced an undesirable 100%
adhesive failure. Under very humid curing conditions, Adhesive 1 and Adhesive 2 both experienced a desirable 100% substrate failure.

~-- 2 :~ ~ 8 4 ~
EXAMPLE 4. SlHEAR STRENGTH TESTING ~ ~
' ~':',..
The adhesive formulations were tested for early shear strength :
under a variety of curing conditions to demonstrate that the aqueous adhesive compositions of the invention showed improved properties under all curing conditions.

In a pre-equilibration chamber, samples were prepared by using a two-part epoxy to glue rectangular pieces of expanded polystyrene foam (1 inch thick) to a wood piece (3 inches by 2 inches). In a like manner, plywood or cementitious board was cut into 3 inch-by-2 inch pieces. A ~ : ~
layer of each adhesive formulation (1/32-1/16 inch thickness) was ~ -:
applied snto the plywood or cementitious board using a spatula and then polystyrene side of the wood piece was firmly pressed against the layer of adhesive. Each sample was then cured at room temperature. - ;~

Before testing, all samples were equilibrated to test conditions.
The sample was then placed in the jaws of a Tinius Olsen Stress Tester with the sample being pulled apart at an angle 180 to the layer of -adhesive. All samples were tested at a crosshead speed of 0.5 inches/minute. Shear strength was reported in polmds per square inch :
as the ratio of the load at break from the Stress Tester (pounds) to the surface area of the test specimen (square inches). The results are reported in Table 4.1. High shear strengths at break are desirable. In addition, substrate failure types are more desirable than adhesive failure types.

:; ' 2108~9~
Tzble 4.1 Compzrative Adhesi;ve A&esive Adh!oive I 1 2 Phrwood Subst~ate She~rstreng~hz~bre~k 7.~ ~.7 ll7 ~pounds/sqllz~e inch) Fzilrlre Iype 100% zdhesive 90% zdhesive 90% adhesive ~ailure fz~lure/10% failure/10%
substrate failure substrate failure NOTES:
Cur~d a~ 75F at d 50% relalivc humidi~y lor 3 hours -- warrn Tesfcd af 75~F and 50% rela~ive humidi~y -- warm Rcported as aueragc of 2 mcasurcme~lls Shearstrenglhzlbrezk 9.0 13.~ 16.2 (pounde/squzre incb) Fziluze type 90% adhesive 80% adhesive 20% adhesive fz~lure/10% fzilure/20% fzalure/80%
substrate fzllure substrate fallure substrate failure NOTES:
Cur~d a~ 75F a~ld 50% relalive humidity Jor 3 hours -- wann Tcs~cd al 75 F and 50% rela~ivc humidity -- warm Repor~ed as avcragc of 2 measurcmen~s The shear strength increased on both types of substrates for the -adhesive formulation made according to the invention (Adhesive 1) as compared to the adhesive which did not contain an amine-containing polymer (comparatiye Adhesive 1) under warm conditions. The shear strength increased on both types of substrates even more for the adhesive formulation made according to the invention which :
optionally containéd multivalent metal (Adhesive 2 -- contained zinc oxide) under warm conditions.
: '. ' ' .

.

Claims

1. An aqueous adhesive composition, comprising:
(a) a film-forming latex polymer having anionic character;
(b) a water-soluble or water-dispersible polymer formed from at least about 20% by weight monomer containing amine functional groups; and (c) a volatile base in an amount effective to raise the pH of the composition to a point high enough where essentially all of the amine functional groups are in a nonionic state.

2. The adhesive composition of claim 1 further comprising a water-soluble or water-dispersible multivalent metal.

3. The aqueous adhesive composition of claim 1 wherein said water-soluble or water-dispersible polymer is formed from at least about 50% by weight monomer containing amine functi onal groups.

4. The aqueous adhesive composition of claim 1 wherein said water-soluble or water-dispersible polymer formed from at least about 20% by weight monomer containing amine functional groups is an N-acryloxyalkyl-oxazolidine.

5. The aqueous adhesive composition of claim 1 wherein said volatile base is ammonia.

6. The aqueous adhesive composition of claim 2 wherein said water-soluble or water-dispersible multivalent metal is zinc.

7. A method for improving the early cohesive and adhesive strength of an aqueous-based non-cementitious adhesive, comprising:
(a) forming an non-cementitious adhesive containing:
(1) a film-forming latex polymer having anionic character;
(2) a water-soluble or water-dispersible polymer formed from at least 20% by weight containing amine functional groups; and (3) a volatile base in an amount effective to raise the pH of the composition to a point high enough where essentially all of the amine functional groups are in a nonionic state;
(b) applying said non-cementitious adhesive to the exterior surface of a building or other outdoor structure; and (c) applying a solid or foamed layer of protective material to said non-cementitious adhesive.

8. The method of claim 7 wherein the non-cementitious adhesive further comprises a water-soluble or water-dispersible multi valent metal.

9. The method of claim 7 wherein said water-soluble or water-dispersible polymer is formed from at least about 50% by weight monomer containing amine functional groups.

10. The method of claim 7 wherein said water-soluble or water-dispersible polymer formed from at least about 20% by weight monomer containing amine functional groups is an N-acryloxyalkyl-oxazolidine.

11. The method of claim 7 wherein wherein said volatile base is ammonia.

12. The method of claim 8 wherein said water-soluble or water-dispersible multivalent metal is zinc.

13. A composite comprising:
(a) a substrate;
(b) an aqueous adhesive formed comprising:
(1) a film-forming latex polymer having anionic character;
(2) a water-soluble or water-dispersible polymer formed from about 20% by weight to about 100% by weight monomer containing amine functional groups; and (3) a volatile base in an amount effective to raise the pH of the composition to a point high enough where essentially all of the amine functional groups are in a nonionic state; and (c) a layer of material to be adhered to said substrate.

14. The composite of claim 13 wherein the aqueous adhesive further comprises a water-soluble or water-dispersible multi valent metal.

15. The composite of claim 13 wherein said water-soluble or water-dispersible polymer is formed from at least about 50% by weight monomer containing amine functional groups.

16. The composite of claim 13 wherein wherein said water-soluble or water-dispersible polymer formed from at least about 20% by weight monomer containing amine functional groups is an N-acryloxyalkyl-oxazolidine.

17. The composite of claim 13 wherein wherein said volatile base is ammonia.

18. The composite of claim 14 wherein said water-soluble or water-dispersible multivalent metal is zinc.