CA1117677A - Internally plasticized polymer latex - Google Patents

Abstract

INTERNALLY PLASTICIZED POLYMER LATEX
Abstract This invention relates to a latex of internally DN 75-119A plasticized polymer particles, low in viscosity although high HLG/sjg in hydrophilic components and film forming at temperatures below the calculated Tg of the polymer. The polymer may be prepared by a multistage emulsion polymerization process.
The first stage is highly water-swellable or water-soluable.
The principal second or later stage is less hydrophilic and of higher Tg than the first stage and is polymerized in the emulsion in the presence of the first stage.

Description

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13~C~GROV~D C)F THE INVl~TI;:)'`l This invention relates to a polymer latex in which the arrangement of-the polymer molecules in the latex ~article is novel. The latexes are useful in the formation of coatings, adhesives and binders. They are particularly use-ful to su~Plant combinations of polymers and coalescentsin polish and coatings compositions. The polis~es or coatin~s may be a~olied to either hard or soft surfaces and are especially useful for aoPlication to flooring and wall surfaces to form clear coatings having a glossy appearance.
The polymer in a film-forming latex is required to be soft enough to form a film of good integrity yet hard enough so the film has high strengt'n, low dirt pick-llp and a myriad of other related prooerties depending on the specific application. It is known that if the glass trans-ition temPerature ~Tg) of the polymer is below the temperature at which the film is being formed, a film of good integrity, that is, not "cheesy", is normally produced on drying a latex. r~owever, the very softness of the latex ?articles which leads to good film formation means that the produced film i, soft or tacky as ooposed to being strong, hard, wear resistant and tough. The art recognized way out of the dilemma of having a polymer which is soft enough to form a well integrated film yet hard enough to form a use~ul film is to add coalescents volatile enou~h to leave the film after film formation has occurred. -~ith the advent of greater concern a~out air pollution, there has arisen the need to eliminate the volatile coalescents if oossi~le.

. . ~k 11~ '7 li Elimination of the coalescentsis also economical, the ccst of the coalescent being saved.
Another approach toward preparing high Tg polymers with low minimum film formation temperatures (MFT) is the incorporation of a high proportion of hydrophilic monomers (e.g. those with hydroxyl, amine or carboxyl functions) in the polymer. This induces ~ater swelling of the latex particles which simultaneously softens the particle in the latex. At normal polymer concentrations the swelling 1~ is accompanied by very high viscosities particularly if the storage or use p~ lS such that the carboxylic groups or amine groups are neutralized or Qartially neutralized.
A further disadvantage is water sensitivity of the final film as well as sensitivity to acidic or basic solutions.
Polymers of hydrophilic monomers made by solution polymeriæation procedures and ap~l~ed in solution are taught by J. Weiss in u.S~ Patent 3,935,368 for use in coating vinyl chloride flooring materials.
Still another solution to the oroble~ of 9etting hard coating in the form of a well integrated film is that of D. Schoenholz et al. in U.S. Patent 3,949,107. Schoenholz teacnes applying a polish containing an aqueous dispersion o o of a resin with a Tg of 30 C. to 80 C. to a floor, having either the polish or the floor preheated to a temperature above the Tg of the resin.
This disc~osure teaches a latex low enough in viscosity to make suitable formulations for application and which, without coalescents, is film forming and produces tough, hard films.

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~'7~'7'7 BRIEF SUMMARY OF THE INVENTION
Thls invention relates to a process for producing a latex of internally plasticized polymer particles, the polymers produced by the process and polishes and other - 5 products made from the latex.
In the present invention it i5 taught that the sequential polymerization of a hard (high Tg) relatively hydrophobic monomer system onto soft (low Tg) hydrophilic functionalized copolymer latex particles, to form latex particles which for convenience are called internally plas-ticized polymer latex particles, produces a latex low in vlscosity yet film forming at a temperature low in comparison to the calculated Tg of the ~olymer in the particles. The viscosity and the MFT are measured under normal use condi-tions, i.e. neutral to high PH for acid-containing polymers and neutral to low pH for base-containing polymers. Pre~-erably, the latex of internally plasticized polymer particles is made as follows:
Under normal emulsion polymerization conditions a water-swellable addition polymer is prepared.
This water swellable polymer may also be water soluble at an appropriate pH and normally is soluble at high pH when containing acid groups or at low pH when containing basic groups. Under the conditions of polymerization, however, it does not dissolve in the aqueous medium but is maintained as a latex. A second polymer, poly-merized in the presence of, interacting with and possibly interpenetrating the first, is formed by the addition of certain monomers less water sensitive, i.e. less hydrophilic, and normally harder than the ~nitial monomer system.

The second ~onomer system i~ chosen to have sufficient com-patibility with the initial polymer so as to swell the initial polymer. The second polymer in its interaction wit~
the first serves to sharply limit the water swellability of S the first polymer. Th~s, the product can be considered to be a hydroplastic first poly~er hardened and made more hydrophobic by the second polymer or alternatively a hard hydrophobic second polymer made softer and more hydroplastic by the first polymer. The internally plasticized ~olymer formed has properties unlike the properties of either parent ty~e of pol~mer nor are the properties si~ply the sum or average of the properties of the parents. For exam~le, if the first polymer is one which is co,~pletely soluble at high pH it is found that after the internally plasticized polymer is formed this first polymer ~ortion is no lonqer soluble even at very high PH valu~s~
A highly water swellable com~onent polymer would be expected to ~roduce a high viscosity latex t even though the MFT might be low co~npared to the Tg. In this invention, the modification of the properties of the water swellable - first stage polymer by the second stage results in the rel~-tively low viscosity of the latex.
-- The present invention then in one aspect, - resides in a latex of internally plasticized addition polymer particies, hav ng a calculated Tg above about 2GC, cornprising: A) a ~irst stage ~olymer ~omprislng at least 10~ h~drophilic mer units comprising nonionic hydrophillc unlts and B) a later stage, less hydrophilic, polymer ~; polymerized in the presence OI an emulsion o~ the first stage polymer, wherein ~he first and later stage polymers are each at least about 20~ of the addition polymer, by ' '','`' weight; the latex having (1~ a viscosity below about 5,00 centipGise~, at 20~ solids over the pH range 4 to 0, and

(2) a minimum fllm temperature more than 5C below Ihe calculated Tg of the addition polymer.
In another aspect, the present invention resides in a latex of internally plasticized addition polymer particles comprislng-A) a first stage polymer, polymerized from amonomer mlx conslsting essentially of monoethylenically unsaturated monomers, comprising, by weight, at least 10%
hydrophilic mers, the hydrophilic mers comprising at least 10~ nonionic and at least 0.5% ionic mers, and B~ a less hydrophllic, higher Tg, later stage polymer polymerized ln the presence of an emulsion of the first stage polymer;
A) being from 20% to 80~ of the comblned weight of A) and B);
the lnterpenetration parameter of A) being greater than that of B) by up to elght unlts.
The invention also provides a process for producing a latex of internally plasticized addition polymer particles, comprising:
(a) polymerizing a first stage polymer comprising at least 10~ hydropnilic mer units comprising nonionic hydrophilic units and (b~ in the presence Or an emulsion o~ the first stage polymer polymerizing a later stage less hydrophilic polymer whereln the ~irst and later stage polymers are each at lea~t about 20% of the addltlon polymer~
by weight, to produce a latex having (1) a vi~coslty below about 5~000 centipoises - 5a ~

r7,~
at 20~ solids and over the pH r~nge 4 to 10, and (2) a minlmum fllm temperature more : than 5C below the calculated Tg of the addition polymer;
the addltlon polymer havlng a calculated Tg above about 2CC.
The present invention, in a further aspect, resides in a process, for producing a latex of internally plasticized additlon polymer particles, comprising (a~ producing a flrst stage polymer, poly-merlzed from a monomer mix consisting essenti~ of monoethylenically unsat-urated monomers, comprising at least 10~ by weight hydrophilic mers, the hydrophllic mers comprlsing at least 10~ by weight nonionlc mers and at least 0.5% by weight ionic mers and (b) polymerizing, in the presence of an . emulslon of the first stage pol~erJ
a later stage polymer ~ess hydrophilic, having an interpenetration parameter higher by up to eight units, and a higher Tg than the ~irst stage polymer, the first stage polymer being ~rom 20 to 80~ by weight of . the total flrst and later stage polymers.

. The preferred polymers of this invention comprise at least one of acrylate~ methacrylate, vinyl ester and . vinyl aromatic mer units. The preferred hydrophilic ionic mers in the polymers comprise a carboxylic acid group. The preferred hydrophilic nonionic mers in the polymer co,nprise hydroxyalkyl esters of carboxylic acids or vinyl alcohol mers.

1~7~77 ~RT~IL.~ CRIDTIO~
~he internally plasticized polymer of this invention is for~ed by emulsion Polymerization of a first ethylenically unsaturated monomer system comorising com~aratively hydrophilic - S monomers and then polymerizing a second c~arge of ethyleni^ally unsaturated monomers which are by themselves, the ~recursors of a harder and more hydroPhobic poly~er tnan the first charge polymer. The polymer ~ormed by the first cnarge or stage is maintained as an emulsion althou~h it is water swellable or water soluble. ~ater soluble, in this usage, ~eans soluble in water when the p~ of the water is adjusted by the addition of acid or base to co~letely or ~aetially neutralize the polymer. r~ater swellable means that the ~oly~er imbibes water or can be made to imoibe water by p~ adjust~ent lS as above. ~t is ~re~erred that the ~1 ran~e considered useful be ~rom about 4 to about 1~. The swellin~ ratio of the swellable poly~er, i.e., the volume of the polymer swollen in a large excess of water divided by the volume of the polymer when dry, is preferably greater than two and more preferably greater than six.
The ~ode of operation of the hydroPhilic mono~er, included in amounts ranging from about 10 to about 100 parts per hundred parts of first charge monomer is believed to be ~ understood but the evidence is not so conclusive that it - 25 should be considered binding. It ap~ears that the hydro-; philic monomer sërves, when polymerized, to bind whatever - a~ounts of water are transmitted into the com~osition, in the manner of water o~ hydration, for exam~le. ~ny monomer -- which can be polymeriæed in the ~ix and which is hydrophilic ,. .

1~7~i77 enough to eEfectively bind water is contemplated within the scope of the inven~ion. ~mong the hydrophilic monomers which can be men~ioned, by way of example only, are acrylonittile, methacrylonitrile, hydroxy-substituted alkyl and aryl acrylates and methacrylates, ~olyether acrylates and methacrylates, ~ Qhosphato-alkyl acrylates and methacrylates, alkyl-phosp'nono-al~yl acrylates and methacrylates, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, N-vinyl pyrrolidone, alkyl and substituted alkyl amides of acrylic acid, methacrylic acid, maleic acid (mono- and di-amides), fumaric acid (mono- and di-amides), itaconic acid (mono- and di-amides), acrylamide,'methacrylamide, also other half acid - for,ns of the above dibasic acids such as half esters, amino monomers such as amino-substituted alkyl acrylates and meth-1~ acrylates, vinyl pyridines and amino al'~yl vinyl ethers, and ureido monolnersr including those with cyclic ureido groups, and the like. Many others will occur to those skilled in the art, and the scope of the present invention should be interpreted to include such hydrophilic mono.~ers generally.
The proper scope of the invention should also be interpreted to include variations on the inclusion of the hydrophilic mono.ner, such as, for example~ w'nen a monomer is included in the polymeri~ation mix which is not itself hydrophilic, but is altered in processing or in a subsequent ste~, e.g.
by hydrolysis or the like, to provide hydro~'nilicity, anhydride and epoxide-containing monomers are exam~les.-Among the e~fective hydrophilic monomers, it ispreferred to utilize aceylic compounds, particularly the amides and hydroxy al~yl esters of methacrylic and acrylic acids, amides and hydroxy alkyl esters of other acids .
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.. . . _ ., .... . . _. , , _ . .. _ . . . . , . , . .. . . . . . . _ .. , ~

1~'7~:i'7~7 are also preferred, but less so than the corres~onding methacrylates and acrylates, wnich are more readily poly-merized. Monomers containing carbox-flic acid are also 2re-ferred,particularly acrylic acid, ~ethacrylic acid and S itaconic acid. Another preferred grouD of hydroPhilic monomers are those re~resenting specieic exa~ples of potential ~ydroohilic monomers which produce the actual hydrophilic mer units in the oolymer by a hydrolysis process.
These monomers are the esters of vinyl alcohol suc~ as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl versitate. ~ydrolysis of these nonomers Produces vinyl alcohol mer units in the ~ol~mer w`nich mer units are hydrophilic. The preferred monomer of these i3 vinyl acetate.
Polymerized with the hydroDhilic monomers in the first char~e are ot~er monomers carefully chosen to give other desirable proDerties to the fin~l polymer. ~ny poly-ethylenically unsaturated monomers, if present, are preferably of the type in which the various ethylenic groups, i.e. the addition ~ol-~merizable unsaturated grouDs, oarticipate in - 20 the ~olymeri7ation at about the same rate. Preferably no such crosslinking or graft-linking ~olyethylenically unsa~urated -- monomers are oresent in the first stage mono.ner system. T~e term graft-linking mono~er is defined in U.S. ~atent 3,79~,771 column 4, line 66 to column 5, line 20.
Preferably the first charge ~onomers are mono-- ethylenically unsaturated.
It is desired that the Eirst charge polymer be softer than the second charge ~olymer. The hardness of the first charge is controlled by the choice of the hydrophilic - - r -~

~3L17~7 - monomers and of the comonomers used therewith. The poly-merizable comonomers which form soft polymers in the presence of free radical catalysts desirably include any pr~mary and secondary alkyl acrylate, with alkyl substituents up to - 5 eighteen or more carbon atoms, primary or secondary alkyl methacrylates with alkyl substituents of five to eighteen or more carbon atoms, or other ethylenically-unsaturated compounds which are polymerizable with free radical catalysts to form soft solid polymers, including vinyl esters of sat-urated monocarboxylic acids of more than two carbon atoms.
The preferred ethylenically unsaturated compounds are the - stated acrylates and methacrylates and of these the most practical esters are those with alkyl groups of not over 8 carbon atoms.
The preferred monomers which by themselves yield soft polymers may be summarized by the formula CH2 = C-COORX
R' wherein R' is hydrogen or the methyl group and Rx represents, when R' is methyl, a primary or secondary alkyl group of 5 to 18 carbon atoms, or, when R' is hydrogen~ an alkyl group of not over 18 carbon atoms, preferably of 1 to 8 carbon atoms and more preferably 1 to 4 carbon atoms.
Typical compounds coming within the above definition are methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, sec-butyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, 3,5,5-trimethylhexylacrylate, decyl acrylate, dodecyl acrylate, cetyl acrylate, octadecyl acrylateJ

_ g _ ~7~7'7 octadecenyl acrylate, n-amyl methacrYlate, sec-a~yl meth-acrylate, hexyl methacrylate, 2-et~ylbutyl methacrylate, octyl methacrylatej 3,5,5-trlmethylhexyl ~ethacrylate, decyl methacrylate, dodecyl met~acrylate, octadecyl methacrylate, and those with substituted alkyl grou~s 5uch as butoxylethyl acrylate or methacrylate.
A5 polymerizable ethylenicallv unsaturated mono~ers, which by themselves form hard polymers, there may be used alkyl methacrylates having al~yl groups of not over four carbon atoms, also tert-amyl methacrylate, ter-butyl or tert-amyl acrylate, cyclohexyl, benzyl or .isobornyl acrylate or methacrylate, acrylonitrile, or ~etnacrylonitrile, these constituting a preferred grou~ of the compounds forining hard oolymers. ~tyrene, vinyl chloride, chlorostyrene, vinyl acetate and a-;nethylstyrene, which also form hard -polymers, may be used.
Preferred monomers, which ~y the~selves form hard polymers, may be su~marized by the formula CE~ = C--X

wherein R' is hydr~gen or t~e methyl group and wherein X
represents one of the groups -CN, ~henyl, inethylphenyl, and ester-forming gro~lps, -C~O~", wherein R" is cyclohexyl or, when ~' is hydrogen, a tert-alkyl groUP o~ ~our to ~ive carbon atoms, or, when ~' is methyl, an alkyl group o~ one .
to our carbon atoms. Some ty~ical examPles of these have already been named. Other s2ecific compounds are methyl methacrylate, ethyl inethacrylate, propyl .nethacrylate, isopropyl methacrylate, isobutyl methacrylate, n-butyl 1~'7&;i'~'7 ~ethacrylate, sec-butyl methacrylate, and tert-butyl methacrylate. ~crylamide and methacrylamide may also be used as hardening com?onents of the copolymer.

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These monomers may contain other functional grouos ~or other purposes such as to oroduce crosslinking in the ~olymer on curing or enhanced adhesion to a substrate. ~xamples of such functional groups are carboxyl, in the form of the free acid or salt, a~ido including sub-stituted amido, such as al~oxy al~yl amido and alkylol amido, lQ e~oxy, hydroxy, amino inclu~ing oxazolidinyl and oxa~inyl, and ureido. In most instances these functional groups are also hydrophilic groups, and many of the monomers are hydrophilic.
Another yroup of monomers of this invention which by themselves yield soft polymers are butadiene, chloro~rene, isobutene, and isoprene. These are monomers commonly used in rubber latices along with a hard ~onomer also useful in this invention, such as acrvlonitrile, styrene, and other hard ~onomers as given above. The olefin monomers, oarticularly ethylene and propylene, are suitable for .soft monomers. Particularly useful first stage copolymers are et~ylene/ethyl acrylate copoly~ers and ethylene/vinyl - acetate copolymers containing added hydro~hilic monomer.
A further class of poly~ers of this invention are polymers of the esters of vinyl alcohol such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyratè
and vinyl versitate. Preferred is ooly(vinyl acetate) and cooolymers of vinyl acetate with one or more oF the follo-~in~ monomers: vinyl chloride, vinylidene chloride 7~7 styrene, vinyl toluene, acrylonitrile, methacrylonitrile, acrylate or methacrylate esters, and the functional group containing monomers given above. In the largely vinyl ester polymers it is preferred tha~ the Eirst stage polymers contain at least 10% and preferably at least 30~ by weight vinyl acetate units with at least 80% being most preferred. Before polymerization of vinyl alcohol esters is complete some hydrolysis to vinyl alcohol mer units normally occurs or is accomplished. The vinyl alcohol mer units so produced are hydro~hilic and considered here as though derived from vinyl alcohol monomer. The amount of hydrolysis can be controlled by means of control of the time, temperature and p~ of the reaction to Qroduce the desired amount of vinyl alcohol in the product. Longer times, higher tem~eratures,- very acidic or very alkaline conditions all sèrve to increase the amount of hydrolysis and thus the amount of vinyl alcohol in the final product. The amount of hydrolysis can be determined by acid-base titration procedures in water or in suitable solvent systems.
A preferred co,nposition of this invention is one in which the monomers of the first stage comprise o5 to ~5~
C -C alkyl acrylate, C -C alkyl methacrylate, styrene, or a mixture thereof, 5 to 10~ acrylic acid, methacrylic acid, itaconic acid, or a mixture thereof and 10 to 25~ hydroxy C -C
alkyl acrylate, hydroxy C -C alkyl methacrylate or a mixture thereof, by weight, and the monomers of the later stage polymer consist essentially of methyl ~ethacrylate, styrene, or a mixture thereof. Ano~her preferred composition is one in which the mer units of the first stage com-prise 5O to 85% vinyl acetate, 1 to 10% acrylic acid, , .. . , . .. . . , . . _~ ~

L7$~`77 methacrylic acld, itaconic acid, maleic acid (derivable from maleic anhydride) or a mixture thereof~ and 8 to 25% vinyl alcohol, by welght, and the mer units of the last stage consist essentially of methyl methacrylate, or styrene mers or a mixture thereof and 0 to 30%, preferably lO to 20~, by weight acid, such as acrylic, methacrylic or itaconic, mers. It is desirable that the acid component of the first stage comprise up to 5%, based on the polymer weight, of maleic anhydride or maleic acid with 0.2 to 2 percent being preferred. In this usage, the term "mer" means the unit, in the addition polymer~ derived from the named monomer by ad-dition to the double bond.
In general the preferred hydrophilic monomers of this invention are monomers with a solubility of at least six grams per 100 grams of water, those with a solubility of at least 20 grams per 100 grams of water are more preferred and most preferred are those in which at least 50 grams of the mon-omer is soluble in lO0 grams of water. The first stage polymer contains at least 10% hydrophilic monomers, 10~ to 70% being preferred, at least 25% is more preferable with the range 25% to 35~ being most preferable. Of the hydrophilic monomer content it is desirable to have at least 0.5% be acidic groups, such as carboxyl group, or basic groups, such as amino groups, in either the unneutralized or neutralized form. It is also desirable that at least 10% of the hydrophilic mon-omer be nonionic, i.e. not ionizable,such as hydroxyethyl acrylate or methacrylate, or produce nonionic mer units such as these hydroxyethyl ester and vinyl alcohol mer units.
The last stage polymer is more hydrophobic and preferably harder than the first stage. By more hydrophobic ~17~ ~ 7 :is meant that-the later stage polymer if polymerize~ alone is less water-swellable than is the first stage ~olymer.
By harder is meant that the rnodulus of the later stage polymer is greater than that of the first stage ooly,ner the measurements being conducted on polymer samples irnmersed in water. It is oreferred that the last stage monomers 7 . /

~ ~ 14 -7~ 7 be monoethylenically unsaturated.
The internally plasticized polymers of the present invention are usually prepared by emulsion polymerization procedures utilizing a multi-stage or sequential technique.
However, they ~ay also be prepared by a continuous poly-merization in which the composition of the monomers being fed continuously is changed, either step-~ise or continuously, during the polymerization. In such a ~olynerization any discontinuous change in the composi-tion of the monomer feed may be regarded as a stage terminal. If there are no abrupt, or appreciably steeper than average, changes in the feed composition to indicate a change from one stage to another, one may regard the first nalf of the polymer feed as rep-resenting one stage and the second half as representing lS a second stage. In-sim21est form, the hydro~hilic polymer is formed in a first stage and the hydrophobic harder poly,ner is formed in a second stage. Either of the ~oly,ners can themselves also be sequentially polymeri~ed, i.e.
consist of multiple stages. ~he monomers of the first stage, togetner with initiators, soap or emulsifier, polymerization modlfiers or chain transfer agents, and the like are Eormed into the initial polymerization mix and poly~erized, e.~., by heating, Inixing, cooling as required, in well known and wholly conventional fashion until the monomers are substantially depleted. ~onomers of the second~and~in turn of any additional ,tage are then added with appropriate other materials so that the desired polymerization of each stage occurs in sequence to substantial exhaustion of the monomersO It is pre-ferred that in each stage subsequent to the first, the ~17~;'7'7 amounts of initiator and soao, if any, are m~intained ~t a level such that polymerization occurs in existing particles, and no substantial number of new Particles, or "seeds" form in the em~lsion.
S When polymerizations are conducted in multi~stage, sequential orocesses, there can additionally be staqes which are, in comPosition and ProPortion~ the co~bination of the two distinct stages, and which oroduce oolymers having ~ro~erties which are inter~ediate therebetween. The hydro~hilic first stage is preferably between 20~ and 80%, more oreferably between 3~ and 70% and ~ost ~referably bet~een 40~ and 60~
of the total polymer. ~here ~ay of course, be lesser stages present before, between or after these t~o of princi~al interest. These other stages are always either smaller than the principal stage$ or can be considered a portion of one or the other of the ~rincipal stages as indicated by their co~Position. It is ~referred that the ~olymeri~ation be in two stages. Tho~e skilled in a given art field will usually Prepare a few internally Plasticized poly~er latex samol~s differing in first to second sta~e weight ratio and select the one with the best Pro~erties for t~e given a~olication.
The equal weight ratio is the starting point for these trials which usually consist of one higher and one lower ratio with the soread of the ratio being chosen by consideration of the final prooerties desired, e.g., hardness, ~FT, latex viscosity, tack~free time, etc.
The cooolymer is preferably made by the emulsion co~olymerization of t~e several monomers in the orooer oro-portions. ronventional emulsion ~oly~erization techni~ues are described in United States oatents 2,754,283 and 2,795,554.

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1~1''7~'77 , Thus the ~onoiners may be emulsified with an anionic, a cationic, or a nonionic dispersing agent, about 0.5~ to 10~ thereof being used on the weight o~ total nonomers. ~hen water-soluble monomers are used, the dis~ersing agent serves to emulsiEy the other monomers. ~ Pol~merization initiator of the free radical type, such as a~monium or potassiu~
persulfate, may be used alone or in conjunction ~ith an ac-celerator, such as potassium ~etabisulfite, or sodiun thio-sulfate. The initiator and accelerator, col~monly referred to as catalyst, may be used in pro~ortions of 1/2 to 2% eac~ -based on the weight of monomers to be copo7ymerized. The ~olymerization tem~erature may be from room temPerature to 90 C. or more as is conventional.
~xamples of emulsifiers or soa?s suited to the polymerization process of the present invention include alkali metal and aminonium salts of alkyl, aryl, alkaryl, and aralkyl sulfonates, sulfates, and polyether s~lfates;
the corresponding phosphates and phosphonates; and ethoxy lated fatty acids, esters, alcohols~ amines, amides and alkyl phenolS-Chain transfer agents, including merca~tans,~olymercaptans, and ~olyhalogen com~ounds,are often desirable in the ~olymerization ~ni~.
~ nother way of describing and defining the first and second stage monomers of this invention i5 by use of t~e solubility ~arameter conce~t. "Polymer ~andbook", - 2nd Edition, J. 3randrup and E~ ~. Immergut, editors ~John '~iley and Sons, ~ew Yor~ 1375) Section IV Part 15 entitled "~olubility Parameter Values" by '~. Burrell, on , . . .
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1~L1t7~i77 pages IV-337 to IV-359, defines solubility parameter, describes how it is deter.~ined or calculated, contains tahles of solubility parameters and gives further references to the scientific literature on solubility parameters. ~he solubility ~arameter is the square root of the cohesive eneregy density which in turn is the nu~erical value of the ~otential energy of 1 cc. of materi`~al, the potential resulting from the van der ~aals attraction forces bet-~een the molecules in a liquid or solid. Burrell describes a number of ways of calculating solubility parameters from ex~erimentally determined physical constants and two ways of calculating them from the structural formula of a molecule. The structural formula methods are normally used whe~ the data for the calculation fro~ physical constants are not availabIe or are considered ~articularly unreliable.
Calculation from t~e structural formula utilizes tables of group molar attraction constants such as those ~iven on Dage IV-33~ in the ~andbook. The table of Small is preferred.
The solubility ~arameter conce~t may be con-sidered an extension of the ol~ rule l'like dissolves like"
recognized from the early days of chemistry. A non-crosslinked ~olymer will normally dissolve in a solvent of similar solubility parameter and a crosslinked polymer will normally-be--swollen by a solvent of si~ilar solubility ~arameter. Conversely, solvents with solubility para~eters far ~ro~ those of the polymers will neither dissolve nor swell the ?oly~er. ~s given by ~urrell the 7~7'~

- solubility ~arameter of poly~ers may be deter~ined, among other ways, by measuring the swelling of the polymer in a series of solvents. Solubility parameter for polymers may also be estimated by calculation from the group molar attraction constants as mentioned above. In the usual situation, it is found that solvents with a range of solubility parameters around that of the polymer will dissolve the uncrosslinked polymer. Those skilled in the art have added the further refinenent of classifying solvents as poorly, moderately and strongly hydrogen bonded.
It is found that the range of solubility parameter for dissolving a given uncrosslinked polymer differs from one class to the next although usually considerable overlap - is observed. Burrell's Table 4 starting on page IV-349 gives ranges of solubility parameters for poorly, moderately and strongly hydrogen bonded solvents used to dissolve a large number of polymers. In Table 5 starting on page IV-354, there is given solubility parameters of a number of polymers determined by calculation and by other methods.
To for,~ the internally plastici2ed polymer syste,m of this invention the first stage -oolymer and monomers of the later stage must be carefully chosen so as to interact to an appropriate degree. There are both upper and lower limits to the degree of compatibility desired between the first stage polymer and the monomer charges of later (second or last as hereinabove described) stages. It is found that the appropriate degree of compatibility may be expressed in numèrical terms by a property based on solubility parameter and herein named the interpenetration para,neter, Ip. The ?~

1~17~i77 interpenetration parameter may be regarded as a solubility parameter adjusted so as to out strongly, moderately and weakly hydrogen bonding solvents on the same scale. For a given molecule, the inter~enetration ~ara eter is defined as the solubilit~ ~arameter Plus the hvdrogen bondinq increment value qiven below. Solubility parametors o~ various molecules, including a number of mono~ers, are glven in Tables 1 and 2 of Burrell starting on page IV-341. These tables also give t~e hydrogen bonding grou~ appropriate for the given molecule. The increment values, a new teaching in this invention, are 17.2 for strongly hydrogen bonding molecules, 7.2 for moderate hydrogen bonding moleculos and 2.8 for poorly hydrogen bonding molecules.
The follo~ing table contains a list o~ monomers along with values of their solubility parameter, inter-~enetration parameter and water solubility. ~lso given is the hydrogen bonding class appro~riate for the monomer.
The solubility parameter values and hydrogen bonding class of most of these monomers are those given in Table 1 of 3urrell. Vinyl alcohol is a special case because, as is well known, this monomer does not have a stable existence. Polymers containing mer units corresponding to vinyl alcohol may be ~repared by hydrolysis of a ~oly-mer containing tne corresponding vinyl ester, such as vinyl acetate, mer unit. T'ne solubility parameter o~ this hypo-thetical monomer is computed by the method of Small as indicated above. Values for other monomers not in ~urrell's table are determined or computed ~ollowing the teachings ~7~7'7 in Burrell's ~Iritings v.~. Dimensions for the solubility paca.neters ~iven in the table are the usual ones, square root of (calories per cubic centimeter). The interpenetration paralneter ha~ the same dimensions. Water solubility is given in gra~s of monomer per 100 gcams of water at 25 C.
The hydrogen ~onding class strong, ,noderate or poor is ascertained by using the nethod of C. ~. Hansen, Journal of Paint Technology, Vol. 39, p. 104-117 and 505-614 (1957).

Interpene- ,~ater Solubility ~ydrogen tration Sol- Abbre-Monomer Parameter Bonding Parameter ubility ~iation Acrolein 9.8 S 27.0 40 ~cr.
~crylic ~cid12.0 S 29.2 ~ AA
Acryloniteile10.5 P 13.3 25-30 A~
o-bro~lostyrene9.8 P 12.6 BrSt 1,3-butadiene~ 7.1 P 9.3 Bd i-butyl acrylate8.5 M lS.2 0~2 iBA
n-butyl acrylate8.8 M 16.0 0.2 ~A
Butyl ~ethacrylate 8.2 M 15.4 0.01 ~MA
Chlorostyrene9.5 P 12.3 ClSt i-decyl acrylate8.2 M 15.4 0.01 iD~
Dichloroethylene 3.1 P 11.9 0.~1 ~CE
Et'nyl acrylate8.6 M 15.8 1.51 ~A
Ethylene oxide11.1 M 18.3 CM EO

Ethylene epi-12.2 S 29.4 EEPC
chlorohydrin Di~ethylamino7.0 S 24.2 CM DI~AE~
ethyl methacrylate ~ihydroxypropyl9.0 S 26.2 CM D~P~
methacrylate Ethylhexyl acrylate 7.8 M 15 r 0 E~A

~7~i~7~7 Interpene~ ater Solubility ~ydrogen tra'ion Sol-Monomet Parameter 20ndina Parameter _bility Abbr~.
Ethyl methacrylate 8.3 ~ 15.5 0.1 E~A
1-hexene 7.4 P 10.2 hex Hydcoxyethyl 8.0 S 25.2 aE.~A
methacrylate Isoprene 7.4 P 10.2 Ipn Maleic anhydride 13.6 S 30.8 16.3(7~) ~.An Methacrylic acid 11.2 S 28.4 CM M~A
~ethyl acrylate 8.9 M 16.1 5.2 M~
Methyl ~ethacrylate 8.8 M 1~.0 l.o MM.~
6~ - methylstyrene 8.5 ~- 11.3 MeSt Styrene 9.3 P 12.1 ST
Vinyl acetate 9.3 M 16.22.3 V~,c Vinyl chloride. 7.8 M 15.0 ~Cl Vinyl toluene g.l P 11.9 Vtol (Vinyl alcchol~ 8.4 S 25.6 (Cl~) VOH
S = Strong P = Poor M - Moderate CM= Completely Miscible As .~aleic acid ~ ~7~'7~

For a la~ex polymer ol this invention, the inter-penetration parameter of the first stage is Kreater than that of the second stage, preferably at least one unit (calorie per cubic centimeterJ greater. However, the inter-penetration parameter of the first stage must not be toomuch greater than that of the second stage. The dif~erence is not more than 8 and is desirably bet~een ] and 6 units.
When the first stage polymer contains 65~o or more, by weight, of Cl-C4 alkyl acrylate, Cl-C4 alkyl methacryla~e, styrene or a mixture thereof, it is desirable that the first stage I~
be not more than 6 units greater than that of the later stage with a difference of 1 to 4 units being preferred and 2 to

3 units most preferred. When the first stage polymer contains 50% or more, by weight, of vinyl acetate it is desir~ble tha~
the first stage Ip be 1 to 8 units greater than that of the later stage with a difference of 2 to 6 uni~s being preferred and 4 to 5 units most preferred. It should be appreciated in this context that the second stage or the later stage may con-tain some hydrophilic monomers and still con,orm to these rules for the difference between the interpenetration para-meter of the first stage and that of the second stage.
In a preferred embodiment of this invention, the first stage contains acidic, preferably carboxylic, mer units as well as other hydrophilic mer units. The carboxylic mer units are preferably obtained from the monomers acrylic aci,-3, methacrylic acid or itaconic acid. The other hydrophilic mer units are preferably hydroxy Cl-C4 alkyl methacrylate, hydroxy Cl-C4 alkyl acrylate or vinyl alcohol units.
The ~iscosity of the polymer emul~ion produced is measured by any o~ the procedures known to those skilled in the art. Preferahly there is em~loyed a ~rookfield ~ync~ro-Letric viscometer ~ocel LV 1 with ~re~erence in : choice o~ spindle and s~eed being given to the combinations w~ich will result in a ~id-range reading. Measure~ents, at ,. . ~

- 2~ -~ ~''7~'7'~

o 20 C, are made at p-d values in the range of 3 to 1~ on emul-sions adjusted, with water, to 2~ solids content. The p~l of acid-containing copolymer emulsior.s is generally ; adjusted by the use of a mineral ~ase, an organic base, S such as an amine, or ammonia with the latter being pre-ferred. Internally ~lasticized polymer latices containin~
basic groups, such as amine groups or quaternary am,~onium group$, have their pa adjusted by the use of mineral acids, such as hydrochloric acid, or organic acids such as acetic acid. The latex viscosity, over the pa range 3 to 10, is generally below 5,~00 centipoises, better still belo-- 500 centipoises, better still below 150 centipoises, better still below 40 centipoises, and most preferably below 13 centipoises; the lower values being particularly desirable for certain applications, such as floor polishes.
The ~inimum fil,n temperature (MFT) is determined on a film cast from the latex at 20~ solids and a p'tl normally in the range between 7-1/2 and 9 for a~monia-neutralized, acid-containing polymers and in the - 20 neighborhood of 3-4 for acetic acid neutralized base containing polymers. The procedure of The American ~ociety for Testing Materials method D2354-68 is followed. The o MFT is more than 5 C. below the calculated glass transition temperature (Tg) of the oolymer when the Tg is above 5 C.
Preferred are MFTs below 18 C. with pol~mers having a Tg calculated for the entire polymer composition of greater than 25 C. The term MFT, as used herein to define certain polymers, refers to the value deter~ined on a latex at the 7~77 pH and solids yi-ien above in this oaragra~h. l-~ so~,e Gf the examples hereinbelow, t~lFT values deteloined under other conditions are given only for comparison purposes and are not the MFTs used in defining the poly~ners Oe t~is ; invention.
S ~ardness is expressed as ~.~noop Hardness N~mber (RH~) determined by means of the Tukon ;~icro-hardness Tester on a film ~orlned by casting t'ne latex on 3 solid ~ubstrate such as a glass panel. It is preferred t~at the polymers have a RHN grea~er than 3 with greater than 5 being more preferred and greater than 8 Inost preferred.
The calculated Tg oE each stage and that of the overall polymer is determined by calc1~1ation based u~on - the Tg of ho~opolymers of individual monomers as described by Fox, Bull. Am. Physics Soc. 1, 3, page 123 (1956).
lS Tables of the T~ of hom~olymers are given in "Polymer Handbook" ~ection III, Part 2 by W. ~. ~ee and R. A.
Rutherford. The desired calculated Tg of the first stage o o is less than 40 C with less than 5 C. being preferred and 12ss than -10 C. being most preferred. The desired calculated rg of the second stage is greater than 35 C.
- with greater than 75 C. being preferred and greater than 1~0 C. being most preferred. The calculated Tg of ~he 2oly~er based on the overall polylner co.nposition is preEerably o o g;eater than 20 C. with greater than 30 C. being preferred for-~loor polish and similar uses. For so~e other uses, such as adhesives, binders and paints, polymers with calculated Tg values belo~ about 40 C, including - subzero values, are suitable.

'7 ` The internallY Tolastici~ed oolv~er emulsions `: of this invention ~ave a noteworthy comoination of oroT~-erties esoecially (l) low minirnu~ n tempe-ature - couPle~ ~ith high hardnes, and high Tg; ar.d (2) low polymer emulsion viscosity even when neutralized. Thus, co,nParatively hard latex oolymer syste~ns can be used wit~ much less coalescent than usual, or no coalescent at all. This utility is oarticularly v~luable in situations in which t~e coalQscent gives rise to secondary disadvantages.
~ecause of the absence or minimization of added coalescer.t in the formu~ation, coatings which develoP hardness at a very high rate can be ~ade from the oolymers of this invention. ~urt'ner advantages i~lied by the elimination of added ~lasticizer, coalescent or organic solvent are lowering of the cost, reduced flam~ability during the ~rocessing and decreased e~ission of toxic and Polluting vapors during and following aPPlication. These proPerties are of ~articular i~Portance in the formulation and use o~ water based in~ustrial c~atings, both clear and ~igmented.
In ink technology, the extre~ely fast drying and non-flam~ability advantages of internally ~lasticized ooly~ers are o great im~ortance. Tn trade sales coatings, the -co~bination of high hardness and low ~inilnuln filTn te~nPerature makes for a block resistant air drying coating. ~ further advantage of the latex of this invention is that for~ulation is very easv,~wnich results in a considerable cost savinq, because of the fewer ingredients and the ease o~ m~xing in the Plant o~eration. The ease of ~ixing Probably results from the la~ex ~ade by this invention being resistant - ~7 -ii'77 to the so-called "~hocking" ~enomenon; that is, t~e latex is not easily flocculated or gelled when mixed with ano~her component o~ the for~ulation. Thus, ingredients usually may be mixed in any order in the usual plant e~uioment and, in addition, the equi?ment itself is left in a much cleaner condition than with ordinary latexes.
As described above, the pol~mer latexes of this invention are particularly useful to replace the latex plus plasticizer or latex ?lus coalescent syste~s whic~
comprise a number of formulations used in a wide variety of a~lications for ?olymer latexes. These latexes are useful in forming free films as well as in foeming coatings such as in paints, lac~uers, varnishes, powdered coatings, and the like. The latexes o~ this invention are ~lso 1~ useful as im~re~nants and adhesives ~or both natural and synthetlc materials such as paoer, textiles, wood, plastics, ~etal and leat'ner and as binders for nonwoven fabricsO They may be used to lower t'ne minimum filming te~perature or to aid in film for~ation o~ other late~
systems when used in combi~ation therewith. ~igments, dyes, fillers, antioxidants, antiozonants, stabilizers, flow control agents, su~factants or other optional in-gredients may be included in the polymer com~ositions of the invention.
The polymer co~n?ositions of this invention can be -apPlied with or without a solvent by casting permanently or removably onto a suitable substrate, particularly for use as coatinqs, fillers or adhesives. ~p~lication by brushing, elowing, di~ing, spraying and ~ther means 7~7 ~

known in t'ne various art fields may be used to a~olv the latex o~ t~is invention. One of the particular advantages of the present invention is that reacti~-e polymers can be prepared for use as air cured or thermally cured coatinqs, S fillers or adhesives without requiring organic solvents, - coalescents or plasticizers although small amounts o~
these materials may be desired. This is ~articularlv valuable for eli~ination of volatile solvents or other volatiles, such as coalescents, decreases a ~otential ecological ~azard.
It is of especial i~ortance t~at the acid grou~s, hydroxvl groups, or other functional groups incorPorated in the first stage oE the poly~erization are available for further reaction such as neutrali7ation or crosslin~in~
1; This availability distin~uishes the internally plasticized ~- ooly~er latex from a latex in wnich a second or later stage so coats or interacts with t~e first stage a~ to decrease or eli~inate the availability oE first stage functional grou~s ~or subsequent reactions. The ceosslinking referred to may be by any of the usual !neans, such as coordination crosslinking, ionic cro~slinking or the for-mation oF covalent bonds. In general, the reactions o~ these latices may be ionic or covalent reactions. Ionic reactions are illustrated by the ionic crosslinking in the a~
cation of these latices to ~loor polishes as taught below~
The formation-of-covalent bonds by reaction with amino~lasts, epoxies, isocyanates, beta nydroxyethyl esters and the like are well known in the art.
The poly~er latexes of the ~resent invention are particularly useful in formulating ~loor polish and are advanta~ously used in the floor ooli-,he, tau~h~ by Zdanowski, u.s. Patent 3,328,325 issued June 27, 1967; by Fiarman, U.S. Patent 3,467,610 issued September 16, 1969;
and a second invention of Zdanowski disclosed in U.S. Patent 3,573,239 issued M~rch 30, 1971.

In general ~olishing comPositions using the polymers of the pres~nt invention can be defined in terms of the following oro~ortions of the main constituent,:
Constituent: Pro~ortion (~) Water-insoluble internally ~lasticiæed addition poly~er, parts by weight........ 10-100 ax............ ~..................................... do.... .O- 90 (C) Alkali-soluble resin............... do.... .0- 90 etting, emulsif~ing and dispersin~
agents............................. ~ercent. 0.5-20 - 15 ~) Polyval,ent ~etal comeound......... do.... .~- 50 (F) Water to ~ake total solids 0.5~ to 45%, preferably 5 to 30~.
(~) is in weight ~ercent on weight of ~+3+C
- (E) is in weight oercent on weight of A.
The total of A, ~ and C should be 100. The amount of C, when present, ~ay be u~ to 90% of the weight of the cooolymer of ~, and preferably from about 5% to 25% of the weight of the cooolymer of ~.
For a nonbuffable, self-polishing com~osition, the wax should not be over 35 parts by weight, preferablv 0 to 25 parts by weight in 100 parts total of ~olymer plus ~ax according to the above table. Satisfactory non-buffable floor oolish formulations have been ~repare~ wit~-out the inclusion of a wax. Thus wax is not an essential '7 compor:ent o~ a sei~-~olis~ing co~osition. For a dry buEahle polish cvmposition, ~he wax should ~e at least 35 Darts by we;~ht on such total. ~xamvles of wetting and dispersing agents include alkali metal and amine saits of higher ~attv acids having 12 to 13 carbon atons, such as sodilJm, potassium, a~monium, or morpholine oleate or ricinoleate, as well as the com,non nonionic surface active agents.
Additional wet.ing agent im~roves the spreading action of the polish.
For polishing floors, the coating ohtained from t~e comoosition oreferably has a ;noo~ hardnQss number of 0.5 to 20 when measured on a ~ilm thereo~ 0.5-2.5 mils thick on glass. This range of hardness ~rovides good resistance to abrasion and wear and can be obtained by the ap~roPriate selection of monomers to be polymerized.
The follo~ing exa~les, in whic~ the parts and percentages are by weight unless other~ise indicated, are illustrative of the invention.

Example l - Pre~aration of Internally Plasticized Polymer mulsion ~ latex with first sta~e, second stage and average ~9 o o o values of -14 C., 105 C., and 34 C. res~ectivelv, is Pre Pared as follows:

~ ~auivment .
~ five liter, four-necked flask is equi~Ped with a condenser, stirrer, thermometer and monomer addition ~umos. ~eating, cooling and nitrogen s~arginq facilities are ~rovided.

1~7~ '7 . ~atQrial Charges Rettle ~.onome~ C~ L~
Raw Material _harqe ~ 2 .~ater 200~ g 400 g400 g Sodiun lauryl sulfate tsur~actant) 16 2 8utyl acrylate (~A) - 600 ,~eth~l ~ethacrylate (~A) - 140 1~00 ~ethacrylic acid (~A~ 0 1~ Hydroxyethyl methacrvlate ~ ) ~ 212 Sodiu~ persulfate in 1~0 g '~ater (catalvst) 12 C. Procedure dd kettle char~e water and surfactant to the kettle and start agitation and nitroaen s~arge.
2. Co~ine the ~aterials o~ each of the ~ono~er charges and thoroughly ~ix to create sta~le l~ono~er emul~ions.
3. ~eat the kettle to ~2-84 C. with continued agitation and nitrogen 3~arging.

4. ~dd the catal~st solution to t'ne kettle and start the addition of ~onomer charge $1 at such a rate that the addition is co,n~leted in about 50 minutes. Maintain the te~erature at 82-~4 C.
throughout the ~oly~eri~ation.

5. When ~onomer charge ~1 addition is co~leted hol~
for 15 ~inutes at ~2-34 C.

6. ~fte~ the hold Period start the addition of ~ono~er charge ~2 at such a rate that the addition is .
co~leted in about 50 ~inutes. Maintain the temperature at 82-84 C. throughout the ?olymerization.

7. When monomer charge #2 addition is co~leted, hold o for 30 ~inutes at 82-~4 C., then cool and filter.
~ sa~ple of the latex is neutralized to a p~ of 9 with ammonia; the ~FT is below 15 C. and the viscosity is 15 centipoise (~rookfield Viscosity; 20% solids). ~ fil~
cast from the neutralized latex has a hardness of 12.1 '~N.
Exam~le 2 - Sequential C~arge Ratio Following the general procedure of Example 1 three internally plasticized polymer latices are prepared having the same first and second stage compositions but diffeeing in the first to second stage weight ratio.
It is found t~at the property ~alance, low MFT
and si~ultaneously low viscosity e~ulsion, is sensitive to the weight ratio of the hard hy~rophobic second stage charge to the soft hydrsphilic first stage charge. Thus, in a given monomer com~osition field, a few experi~ents ~ay be needed to determine the charge eatio re~uired for the product of this invention. Table 1 shows the effects - of changing the charge ratio, Exa~ole 23 having a low MFT, low viscosity when neutralized and a high ~9.
It is seen that Example 2~ is a latex polymer of this invention whereas the Example 2A is much too high in viscosity at pH 9 and 2C is too high in MFT.
. .

- 33 ~

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" - 34 -,.....

~7~'77 ~xa~le 3 - Yo~y~Pri7~ation Pr~cesa The difference between 3 single emulsion col~oly~er, an internally ?lasticized poly~ler and a ~hysical blend of two ~oly~ers is seen in the ~ata in ~able II. ~11 o~
S the polymers were orePared by emulsion poly~erization following essentially the ?rocedure of F.xa,~le 1 except for tllere being no second charge in the preDarations of Exam?les 3~ and 3C. The overall co~?osition of each of the three examples is the sa~e; t'ne calculated Lg is ~ 10 47 C.
- T~L~ II

Poly~er Co-,~position ~A/~M~ ~A~ FT/Viscosit~
1~ Exam~le ~ A//'~A Descri~tion ~T~ 3 ?q 9 3~23/~6/'.~ //3 single charge, 52/3 46/55 . ~ sim~le coDoly~er 3323~/o/15//50 internally ~las- 40/~ 1~/140 ticized polymer 3C23/~/6jl5//50 physical blend 10/13 10/
gellation a Physical blend 5Q:~0 of ~A/~ : 46/12/12/30) and ' (~MA: 100).
The ~olymer of ~xa~ple 33 is the same as that of Exa~12 23.

It is seen, in Ta~le II, t'nat the single charge poly~er ~xam?le 3~ has an ?~T in the neighborhood of the calculated ~g. T~e physical ~lend, i.e. ~xa~le 3~: a ~len~
of an e,~l~lsion having the composi'ion of the first stag~
of the r~xam~le 3~ polymer with one having the second stage 33 coln~osition, is so viscous at high ~Y that t~e emulsion gels even when diluted to 20~ solids before p~ adjustment.

1~7~'77 Note that neutralized to a p~ of 9 the internally plastici~ed poly,ner has a much lower ;IF~ and only a moderately 'ni~'ner viscosity than t.he single charge copoly~er.
- Example 4 - 3alance of Rydroohile/~ydrop'nobe Charac'er of Stages Using the polymer emulsion of Exam?le 23 as a control, the compositional relationshi? between the water-s~elled first stage ~olymer and that of the second stage is varied. Interaction of the first stage oolymer with the second stage is sho~n by achieve~ent of internal plasticization, ~ith controlled viscosity, by sequentially charged tl) soft, hydrophilic and functionalized and (~) hard and hydropnobic copoly,ners~ This internal ~lasticization is de~nons~rated to depen~ on the bal~nce of hy~rophobe/
hydrophile charactet of the two monomer charges by the data in Table III.
T~LE III
Tq MFT/Viscosit.y ~xam~le Composition (1) (2) ~ ~ 9 4A* ~ S~A/i~lAA/'~EI~A//i~MA 4 100 47 40/ 1~/
23/5/~/15//S0 ~ 1~0 4~ B~/~MA/il~A/~ 5AJ/~M~ -13 ld5 3~ 30/ 15~/
29/0/~ //SJ 10 7~
4C EA/~ /'d~ltlA//l~MA14 lOS 53 55/ 1~/
2~ 29/~/1S//S~ 1~ 1403 4~ 3~/t~M.~ A/TIE~//JT4 100 4~ 20/ 10/
~2.5/6.;/6/1~ 10 30,00~
*The polymer emulsion of Emulsion 4~ is ~he same as tnat o Example 2~.
The results, in Table III, show ~hat vs. ~xam?le 4~ a more hydrophobic, i.e. less hydro~hilic, first stage polymer is good, 4B, a more 'nydrophilic first stage, 4C, leads to high viscosity; a too hydrophobic second stage, 4~, leads to ~L~17~'77 very high viscosity at high p~, too high for ~st l3~5.
~xample S - Intecpenetration Par~meter Emulsion polymers of a number of co~ositior.s, differing in interpenetration parameter (Ip) of the two stagesr are prepared by the 2rocedure o~ Example 1 or Exampl~ 8 (Examples 5E, 5I and 5~). Determinations of the e~lsion viscosity and .~FT, done on the emulsion neutralized to a pil in the cange of 7.5 to 8.5 with ammonia and diluted to 2d~ polymer ~olids, and of the film hardness show ~'nich of the prep~rations have formed internally ~lasticized . . ~olym~rs. Tables IV.A and B present these data.
TAELE IV.A
Example Composition Ratio 5,~ ~A/MMA/MAA!HEMA//MM~ 23/6/6/15//50 5B BA/MMA/~AA/~EMA//MMA 30/7/3/10//50 5C aA/~'~MA/MAA/HE.~1A//MM~ 30.5/3/3/7.5//50 : SD BA/~MA/.~A.A/rHEMA//MMA 34.8/3.4/4.3/8.5~/43 5E EA/VAc/~rOH/~An/AA//ST 5.5/37.8/5.~/0.4/0.7//50 5F 3A/MMA/~AA/~qPMA//MMA 25/11.5/S/7//50 2~ 55 8A/MM~/~AA/VAc/VO~-.H//MMA 23/6/6/13.5/1.5//50 5H 3A/M.MA/~MAEMA//MMA 18/17/15//50 SI EA/VAc/~rO;~//ST 24/23.9/2.1//50 5J ~A/MMA/MAA//~/A~ 2;/21.5/3.5//30/20 5K BA/MMA/.~AA/HEMA//ST 22.5/6.5/6/15//50 5L MMA//3A/MMA/~AA/~MA 50//2.3/6/6/15 SM BA/VOa/VAc//MMA 24/2.1/23.9//50 5N BA/MMA/MAA/~PMA//MMA 25/11.5/~/7.5//50 BA/MMA/MAA/HEMA//MM~ 30/7j3/10//50 5P 3A/MMA/MAA/r~EMA//MMA 30.5/8.25/3.75/7.5//50 5Q BA/MMA/MAA//ST/A~ 25/19/6//30/20 5R EA/S'r/MAA//ST 21/24/5//50 ~7~'7 ~1 ~ ~oao ~n~ ~er o~o ; ooo ooo o,,~ ~o~o o~9o o~o~
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1~1'7~'77 Notes for Table IV.B
lr Viscosity is measured on the latex, 2~
solids brought to a pd of 9 with ammonia except for Example SH which is at p~l of i 3 with acetic acid.
2. ~FT, in degrees Celsius, latex supplied at 20~ solids and pH 9 with ammonia exce~t Example 5~ 3 as above).
3. Hardness is expressed as Xnoop ~ardness Number (KHN) determined by the procedure given in ~esin Review, Yol. XVI, No. 2, p. 9 ff (196~), a publication of the Rohm and ~aas Company.
4. Tg i, calculated for a hiqh polymer by the procedure of Fox, v.s. "(1)" and n(2)" re~-resent first and second or later stage and n~vg.l- the value calculated for the com-position as a whole.
5. Ip is calculated for the first stage (1) and the second stage (2). The difference between these I~ values is tabulated under . _ n ( 1--2) ~ .
T~e data in Table IV.~ show that an internally plasticized polymer is obtained, as indicated by the glass transition temperature, minimum film temperature, emulsion viscosity and hardness values, when the interpenetration parameter value of the first stage polymer is greater than that of the second but not too much greater. Example SJ, a polymer latex of the prior art, is not one of internally ,, ,,~

1~:17~ 7 i~

plasticized particles as evidenced by ~he ~roximity vf the Tg and the ;~FT. As indicated in Table LV, A this polymer has only seven percent hydrophilic mer units in the first stage polymer. Example 5~ is not oE internally plasticized particles of this invention as evidenced by its high viscosity;
as indicated in Table IV, B its composition is such that an undesirably high difLerence in the I~ exists between the polymers of the two stages. Example 5r~ is not of this invention, its viscosity is so high a gel ~orms; note t~at the Ip difference between the polymers of the two sta~es is too low, it is below zero. Examples 5~ and 5R, poly~er latexes of the prior art, have MFT values above their Tg values; neither contains nonionic hydrophilic monomers in the first stage.
ExamPle 6 - Floor Polish A floor polish is prepared by mixing ingredients in the follo-~ing recipe (except Examples 6A and 6~ as noted below):
Role Material Charge Ve'nicle Polymer emulsion -- 15~ solids 100.0 parts Wax Poly ~-40 - 15~ solids 15.U parts (Trademar~, Cosden Oil & C`nemical Co.) Wetting aid Fluorad FC128 - 1~ solids 0.5 paEts (Trade,nark, 3~ Co.~

Leveling Tributoxyethyl ~hosphate - ~.5 parts aid 100~ accive DeEoamer SWS-211 - 5d~ solids (Trade~ark 0.~1 parts Stauffer Wacker Silicone Corp.) Base .~mmonia - 10~ aqueous to p~ ~

The floor polis'n is applied and tested by the 30 procedure described in detail in Resin Review, Volu~e XVI, ilo. 2, 1966 published by ~oh~ and ~aas Como2ny, Philadelphia, -4~

7~7 ;
Pennsylv2ni~ l9105 e~CeQt when arlother procedure Is speci~ied. Polyï,er em~llsions ~sed an~ t'ne test results obtained are in Table ~.A and V.~.
TABLE V.~
S Example 6A 5B ~C 6D 6E _ Polymer emulsion (note 1) Ex. 2B Ex. 50 Ex. ~P Ex. SE
(note 3).(noce 4) Test(note 2) Visual gloss One coat g-vg vg vg vg g-vg Two coats vg vg-exc. vg~exc. vg-exc. vg Leveling One coat exc.exc. exc. exc. exc.
Two coats exc.exc. exc. exc. exc.
. o 60 gloss(T.~ 3) 71 ~2 79 80 77 '~eel mark resistance( r~l, ) vg-exc. g-vg vg vg-2xc. fair r~ater resistance(T;~I 4) One hour good exc. exc. exc. exc.
One day g-vg exc. exc. exc. exc.
~eter~ent resistance(T~ 6) ~ne day vg good good vg --Three days vg-exc~ - -- fair ~even days vg-exc. vg vg-exc. vg-exc. --Re,novability(TM 7) vg exc. exc. exc. fair Static coeff.
of friction(~l 1) 0.5 0.6 0.~ 0.6 --Powdering(T~ 2) sligllt nil nil nil --Notes for T~L2 V.A
1. Exa~nple 5~ is illustrative of the state of the art.
It employs a flocr polish polymer emulsion having 1.65 zinc ion crosslinker. This polis~ is prepared by - mixing ingredients in the following recipe: -., ' '7~7 Role Material Char-~e -Vehicle BA/MMA/,~A~ co~oiy~er ernulsion 80 parts - 15~ solids Wax Poly EM-40 - 15% solids 15 ~arts (Trademark, Cosden ~il and Che~ical Co.
Alkali Solu- low molecular weight all acrylic resin ble Resin - 15~ solids 5 parts Coalescent diethyleneglycol monomethylether 4 parts Plasticizer dibutyl phthalate 1.0 part Wetting aid Fluorad FC-12~ - 1% solids 0~4 ~arts (Trademark, 3M Co.) Leveling aid tributoxyethyl phosphate - 100~ active 1.0 part Defoa,~er ~W-211 - 50~ solids 0.31 parts 1~ (Trademar~, ~tauffer -~acker Silicone Co.) 2. Application of the floor polishes i5 described in ;~ ASTM method D1435-64, ~ethod B. (ASTM - American Society for Testing l~aterials, ~hiladel~hia, Pennsylvania).
Test methods, identified in brackets, are listed below.
3. Example ~ is for~ulated wi-h 1.25~ zinc ion on e.nulsion poly;ner solids.
4. The reci~e for the ~olish of Exam~le 6~ differs from that for 68, C and D in the omission of wax and defoamer 3 and the addition of 2 parts o~ coalescent, diethylene-glycol monomethylether.
Test .`~ethods for TA~LE V.A - given in brackets in t`ne ~able.
1. Slip: ~STI~ ;nethod ~2047-72; panels conditioned at 25 C.
and 55~ relative humidity.
2. Powdering: -~s~r~ method D204~-69.
3. 6~ gloss: ASTM methood ~1455-54 - Vinyl tile t~entile No. R-44, ~entile Floors, Inc~) substituted for OT~
tile in this ~est.

,, .

'7~i'^i7 4. Water resistance: ASTM method ~1793 55, dyna~ic test procedure.
. ~ubber heel mark resistance: CSM~ method 9-73 ~Chemical Specialties Manufacturers ~ssociation, Washington, ~.CO)~
test modified by rotating 15 ~inutes in each direction.
S. Detergent resistance is run on ~lack vinyl asbestos tile using 10 ml. of 5~ aqueous Forward (trademark S. C.
- Johnson) detergent, running 50 cycl-s in the one day, 75 in the three day and 100 cycles in the seven day tests.
7. Removability is run for 75 cycles using 10 ml. of 3~
Spic and Span (tradelnark Procter & Ga~ble) and 1~ -aqueous am~onia, on black vinyl asbestos tile Wear tests are carried out in a corridor having a vinyl asbestos tile floor which is subjected to a daily traffic load of 3,500 to 4,000 pedestrian passes. ~ section of t'ne corrido~ (13 feet wide by 24 feet long) is cordone~
o~f and stripped of residual polish and repolished in the typical janitorial procedure, as follow~:
The floor dust .no?ped to remove loose dirt, 2~ a 1:1 aqueous solution o~ commercial stripper solution, R
Step-~ff (~. C. Johnson & Sons, Inc., Racine, Wlsconsin 53404) is applied by string mop at a rate of ca. 1,000 square feet/gallon; after a 5 minute soak period, the floor is scrubbed with a 1~ inch black strip?in~ floor pad (3M Co~pany, St. Paul, Minnesota 55101;"Scotch Brite"*
Sli~ Line Floor Pad #51-6520-0105-0) on a 300 rp~ floor ~achine (hercury Floor ~achines Inc., Englewood, ~ew Jersey, ~odel ~-15-c); the stripped floor is thoroughly rinsed twice by damp mopping with clear ~ater, and allowed ~43~
* Trademark ~'7~'~7 to dry. The strippe~ floor is divided into o ~oot sections perpen~icular to t'ne nor~al direction oE corridor traEic flow. To each o~ these sections a coat of the 301ish to be tested is applie~ ~ith a string mop, at a ra~e of ca. 2,000 square feet/gallon~ After allowing one hour for the initial polish to dry a second coat is applied in t~e same manner. The appearance of the polishes is rated initially and aft2r one and two weeks of heavy traffic.
T'ne results of ~'nese observations and other tests, Eollowing 1~ the Qrocedures used in obtaining the Table V~. dat~, are in ~able V.3.
T~L~ V.B
Example 6A 6B 6C 6D
Initial:
~loss (visual) vg vg vg~ vg+
Leveling exc exc exc exc Recoatability exc vg-exc vg-~xc exc One week traffic:
05s ( visual) g-vg vg vg vg+

~irt pick-up resistance exc exc exc exc 31ack 'neel mark resistance vg-exc vg vg-exc vg Scuff resistance vg-exc vg+ vg-exc vg 2~ Two week traffic:
Gloss (visual) good good good~ good+

Dirt pick-up-- -resistance vg vg vg vg-Black heel ~ark : 30 resistance vg vg- vg vg -~cuEE resi,tance g-vg g-vg- g-vg g-vg '7g~ 7 The abbreviations used in Tables V.A and V.~ are:

exc = excellent; vg - very goocl; g = good; + = pl~s;

- = minus except when used between abbre~iations, ~here it means 1I to" .
Rxam~le 7 - Lacquer and Paint . .
The polymer latex of Example 1 is for,~ulate2 as follows:
xample 7~: Adjust the 40~ solids latex to ~ 9 with 14~ aqlleous ammonia.
ExamPle 7B: To 100 parts by weignt oE the latex, adiusted . .
to pH 8.5 with 14% aqueous ammonia, is added a mixture of 9.7 parts of water and 15.3 parts oE butoxyethanol.
xample 7C: The ingredients are mixed as follows:
Parts by Weight ~ater 4.7 Tamol 1~5 (22~ aqueous) 1.3 Triton CF-10 (100~) 0.16 ~opco ~XZ û . 05 2d Zopa~ue RCL-g (Ti~ ~igment) 18.8 Grind on high s~eed di~erser ~4,000 ft/min.) for is ,nin. and letdown under agitation ~ith:

Polymer latex 70.4 Water 1.8 8utoxyethanol 2.8 TOTAL 100.0 Trade~ark, ~ohm and ~aas Company, Philadel~hia, ~a.

Trademaek, Diamond Shamrock Chemical Comoany Trademark, Glidden-Durkee Division, SCM Cor~oration ~ey lacquer and paint ~roperties are determined by followin~ the usual paint industry ~rocedures. Results of the deter~ina~ions, on films made from the formulations by coatin~ ,netal sheets, are in Table Vl.
TABLE VI
tl) Prooerty Ex. 7A F`X. 7B Ex. 7C
~ry to touch/tack free time (min. at 25 C and 40% ~.~.) 19/21 Air dry hardness Rr1~, 1 hr.
at 2; C an~ 40% R.~. 6.5 ca. l Ultimate hardness XHN 6.5 6.5 (baked 30 min.
- Hot print (oO C/lo ~r./4 psi) (baked 2~0 F/~0') none nonev. 51. trace Mandrel flexibility (1.5 ~il/
1000~1 hr. at 250 F) (1/2, 1/4, 1/8 inch blends) 0/l/1 //1 //7-8 I~npact In-Lb (D/~) ~lodinei ~ ~2) - 1200~* S0/16 T-~end T - T

20 ~ater Soak (lo hr. at 100 F~ moderate moderate modecate rust, no rus~, mod rust, mod ` blisters blisters blisters Cleveland ~ondensing Cabinet sl. rust, ( lo hours at 40 C) no blisters Che~ical and stain resistance:
~lcohol (lo hours) moderate moderate moderate attack attack attack Ink (30 minutes) no attack Mustard (30 minutes) no attack 33 hipstick (30 minutes) no attack Gasoline (30 ~in.~ slight sl. to sl. to attack moderate moderate attack attack . 1 ~esults deter~ined on 1.5 mil thick films baked 1 hour at 250 F. for ~iln tests unless other conditions are noted.

- ~ir dried fil~s have values of 2/1.
t trademark -4~-., 7~7>7 The data in Table VI.~ indicate that the Exa~n?le7A latex dries very rapidly to full hardness, to for~ a film which is both hard and flexible, without the aid of a coalescent. Coalescent slows hardness develop-nent and has a deleterious effect on some resistance properties.
Baking is required to maximize certain properties. The resistance prooerties are good in general although water soak and alcohol resistance results are not as good as the other results.
; 10 Example 7C shows that the latex of Exa~nple 1 can be elnployed to forn pigmented Eilms ~ith co~nparatively little coalescent. The p~ysical properties of the film forined parallels that of the unpiginented film. Other tests on the film formed from Example 7C indicate:
moderate rustin~ of a sa~ple ex~osed Eive days in a humidity cabinet, signs of failure after three days in a salt s~ray cabinet and a change in gloss after 32 hours at 38 C. in a Cleveland Condensing Cabinet as ~ollo~s:
o o o Initial (20 /~ /80 ) gloss 54/77/8~
-o o o Final (20 t50 /~ ) gloss 21/60/72 ExamPle 8 - An Internallv Plasticized Polymer 3mulsion 3ased on Vinyl Acetate latex, uith ~irst stage, second stage and average Tg values of 25, 100 and 5~ degrees CelSius res~ectively and Ip values of 17.5 and 12.1 for the first and second stages resQectively, is prepared as follows:
A. Equipment A five liter, five-necked flask is equipDed ~itn a sondensor, an eEEicient agitator, a thermometer, addition funnels and heating, cooling and nitrogen spar3ing facilities.

-~7 ,~ .

L'7~'7~

3. ~aterial Char~
Mono~er Charge T~ettle Raw ~aterial 1 1~ 2 harqe deionized water166.39 154 9B83.7g octylphenoxy poly (39)ethox~et~anol 3.4 5.1 1.7 ~bex 18S (33~) (T~ Alcolac Inc)8.5 12.8 4.3 sodium do~ecylbenzene sulfonate (23~)S.8 10.2 3.4 ethyl acrylate37.8 - 19.1 vinyl acetate298.~ - 150.8 styrenQ - 517.5 maleic anhydride4.1 1~ acrylic acid - 7.2 - -Initiator: ~e (0.15% Fe~O .Z~ 4 ml ~ 0.269 am~onium oersulEate ( AP~ ) - in 8g water.
0.269 sodiu~ sul~oxylate for-23 ~aldehyde in 8g water.

Catalyst: 1.92g ~PS and 0.32g t-butyl hvdro-~eroxide (t~r~P) in 113g water.

Activator: 1.92g ~a~SO in llOg water.

Chaser: 0.52g t3,r~P in 5g water.
0.39g sodiu~ suloxylate for.mal~ehyde in 5g water.

C. Procedure .
The ~ono~er charges and kettle c~ar~es ace weighe~
se~arately and each is ~ixed to form an emulsion. T'ne initiator mix is ~repared and char~e~ to the kettle. ~fEicient kettle stirrin~ is maintained throug~out the entire reaction _ 48 7~ 7 ' sequence. ~he hea~ o~ reacti~n drives the kettle o o temperature Erom 22 C to a maxi~num (ca ~0 C in ca. 7 min.~.
At the te~perature maximu~, monomer charge 1 addition is begun at a rate of 13 ~ in and addition of the catalyst solution and activator solution is begun as seParate Eeed streams at a rate of 1 ml/min. The reaction te~perature is ,~aintained at ca. 62 C throug'nout.
r~hen one half of the nono~er char~e 1 addition is com?l'eted (ca. 22 min) charge 1~ is ~ixed with the re~ainins mono~ers of c~arge 1 and the addition continued. ~fte~ about 45 i~inutes this ~ono~er charge ~1 + 1~) addition is comoleted and the kettle contents are maintained at ~2 C for lS ~inutes. ~onorner char~e 2 addition is then begun at a rate of 13 ~ .in. This 1~ second addition is completed in about one hour and the kettle ,contents are maintained at 62 C for 10 ~inutes while the catalyst and activator char~es are completed. T'ne reaction ~ixture is held at 62 for an additional 15 ~inutes and then allo~ed to cool to 55 C. The chaser is now c~ar~ed ra~i~ly, and the o ', reaction l~ixture ~aintained at 50-50 C for 15 minutes.
The product is allowe~ to cool to roo~ temperatllre and is packaged.
~ sample of the ?roduct latex is neutrali2ed to a p'd of 8.5 with am~onia and is Eound to have a viscosity of 4d centiooise (2~ solids 3rookfield Synchro-Lectric Viscometer ~odel L'~l s~indle 1 at ~0 ~ rp~) and a ~FT below 15 C. ~ fil~ cast fro~ this sa,nple -, 'nas a hardness o~ 17 '~

_ ~9 _ Example 9 - An Internally Plasticized Polymer Emulsion Ha;~in an Acid-Cont~nin~ Last Sta~e A latex, with first stage, second stage and average Tg values of 28g 112 and 65 degrees Celsius respectively and Ip values of 17.5 and 14.5 for the first and second stages respectively, is prepared using the same equipment as Example

8 and a similar procedure as follows:
Material Charges Monomer Charge _ _ Kettle 10 Raw Material 1 lA 2 Charge deionlzed water 154~0 g~ 64 g~ 154~0 g~ 832 g~
octylphenoxy poly (39)ethoxyethanol 5.1 5.1 '`Abex 26~"( 33~) (TM Alcolac Inc)12.8 12.8 sodlum dodecylbenzene sulfonate (23%) 10.3 10.3 ethyl acrylate 56 ~ 9 vinyl acetate 449 ~ 3 _ _ styrene - 440 ~ 0 methacrylic acid 7.2 77~6 maleic anhydride - 4 n 1 - ~
Initiator: Fe++ (0.15% FeS04 6H20) 6~4 ml 0.26g ammonium persulfate (APS) in 8g water.
0 ~ 26g sodium sulfoxylate for-maldehyde in 8g water.
Catalyst: 1. 92g APS and 0. 32g t-butyl hydro-peroxide (tBHP) in llOg water.
Actlvator: 1. 92g NaHS03 in 110 g water.
Chaser: 0. 52g tBHP in 5g water.
0.39g sodlum sulfoxylate formaldehyde ln 5g water.
y i'77 Procedure 1. Charge kettle and ad~ust temperature to 20-22C; sparge with N2.
2. Prepare charge 1 and add 231 ~. to kettle.
3. Add maleic anhydride in water and methacrylic acid (charge lA) to remainder of monomer charge 1 and emulsify.
4. Add initlator; turn off N2 sparge.
5. Within several minutes of initiator addition, an exo-thermic reaction occurs, wi~h the temperature peaking at 55-60C.
6. At the peak, start addition of monomer charge 1 and half of the catal~st and activator. Allow temperature to rise to 62C and hold at 62C throughout addition.
7. Charge 1 addition takes 40-45 mlnutes; when charge 1 and half of the catalyst and activator have been added, hold system at 62 for 20 mlnutes.
8. After 20 minutes, start addition of charge 2 and of catalyst and activator.

9. Addition of charge 2 takes about 55 minutes; addition of catalyst and activator takes an additional 10 minutes.

10. Hold for 30 minutes at 62C.

11. After hold period, cool to 55 then add chaser and hold for 10 minutes before cooling to room temperature.

12. At room temperature, ad~ust PH to 4.5-5.0 with 10%
NH4~C03 aqueous solutlon.
A sample of the product latex has a viscosity of 19 centipoise (20~ solids Brookfield Synchro-Lectric Vlscometer Model LVl splndle 1 at 60 rpm) and a MFT of 37C.
A fllm cast from this sample has a hardness of 14 KHN; when 1% Zn~+ (as ZN(NH~4(HC03~2) on polymer sollds is admixed, as taught in US Patent 3,328,325, the hardness of a film is 1505 KHN.

'7 Example 10 - Effect o~ Hydrophilic Monomer Level Following the procedure of Example 9, a group Or polymer emulsions are prepared having the compositions and properties given ln Table VII. From these emulsions floor 5 polishes are prepared by mixing lngredients in the following recipe:
Role Material Charge Vehicle Polymer emulsion--15% solids 90.0 parts Wax AC 392--15% solids 10.0 parts (Trademark9 Allied Chem. Corp.) Wetting aid Fluorad FC128--1% solids 0.5 parts (Trademark, 3M Co.) Levellng Tributoxyethyl phosphate-- 0.5 parts ald 100% active Coalescent Methyl"Carbitol"*- 4.0 Base Ammonia--10~ aqueous to pH 7~5 Each floor polish is applied and tested by the procedure described in Example 6. The results are in Table VII where the superior polish properties of lOD and lOE are noted.
The AC-3~2 is prepared at 35% solids, âS follows~
and is diluted to 15% solids with water.
Formulatlon Parts by Weight A-C Polyethylene 392 40 - Octylphenoxy poly(9)ethoxyethanol 10 KOH (90~0 Flake) 1.2 Sodium Meta Bisulfite o.4 Water #1 to 50% Solids 50 Water -~2 to 35% Solids 43 Charge the first five ingredients to produce the 50% con-centrate into a stirred pressure reactor. Begin agitation and heat to 95C (203~F) with the vent open. Close the vent and continue heatlng to 150C (302~F) for 1/'2 hour.

* Trademark, Methyl "Carbitol" is diethylene glycol monomethyl ether.

~176;7~

Add water ~2 (43 parts ? at 95C (203F) to the reactor while the temperature is at 150C (302) and then cool to room temperature with agitation as quickly as possible. ~dd 500 ppm formaldehyde preservative. - --- 7 - 52~ -7~ '7 ~ \ CO U~ o ~ ~
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~"7~ 7 Example 11 - Effect of Acid Variations Follo~.ving the procedure of E~ample 9, a group of polymer emulsions are prepared having the compositlons anc]
properties given in Table VIII. Floor polishes are prepared from these emulsions and are tested as described in E~ample 10. Results of these tests are in Table VIII wherein it is seen that Example llA does not have pronounced wea~nesses and that the copolymers utilizing maleic anhydride are not hazy.

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~'7~ '7 Example 12 - First Stage/Last, Stage Rat~o Variations .
Polymer emulsions are prepared, by the procedure of Example 9, hav~ng ~ range of first stage to last stage weight ratios as shown in Table IX. The composition of the ; 5 first stage of each is EA/VAc/VOH/r~An/MAA = 11/75.6/11.2/0.~/1.4 and has a Tg(l) of 27.7C and an Ip(l) of 17.5. The last stage of each is ~olystyrene having a Tg(2) of 100C
and an IP(2) of 12.1. Thus the Ip(l) - Ip(2) value of each latex polymer is 5.4. Floor polishes are prepared from these emulsions and tested as described in Examples 6 and lOi test results are in Table IX.
Table IX
Example 12A 12B 12C 12D l?E
Polymer emulsion First//last stage70//3060//4C50//5040//60 30//70 - (by weight3 viscosity*~cps) 22 21 24 20 17 Tg-average C L~6.3 53- 60.0 67.3 75-Polish properties Visual haze nil nil ni] slight moderate Visual gloss good good+ good good fair-gd Leveling vg vg+ vg vg vg Detergent resistance fair fair fair good vg Removability fair fair fair poor poor Heel mark resistance good good good good good Overall wear resistance good good good+ good good *At 40~0 solids and a pH of 5.

F.xample 13 - ~Taleic Anhydride/Methacry]ic Acid Levels .
Polymer emulsions are prepared, by the procedure of Example 9J with a range of maleic anhydride and methac ylic acid levels in the first stage as shown in Table X. Each 5 last stage is polystyrene and represents 50 weight percent of the polymer. The polymer of Example 13A is the same as that of Example llA. The compositional differences ~eing comparatively small the Tg values and the Ip values for the other.three polymers are but little different from those for Example 13A. Polishes prepared from these emulsions are tested as in Examples 6 and 10 to give the performance results recorded in Table X. A wide range of removability and of detergent resistance is achieved; remarkable in view of the vinyl acetate content of the polymer.

7~171j~

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~Y~ 7 Example 14 Ac~d Ln the La,st S'cage I'he polish Or Example 14A is prepared from the same polymer latex as that of Example llA. A film of thls polymer is found to have a Knoop Hardness Number of 10.
The polish of Example 14B i3 prepared from the polymer latex of Example 9 and is crosslinked with 1% Zn++, on polymer solids, added as Zn(NH3)~(~C03)2. The polish of Example 14C is prepared ~rom a sample of the polymer latex of Exampie 6A, Table V. A, Note l; a f-ilm of this polymer has a KHN OI' 13. These polishes are tested as in Examples 6 and 10; the results are in Table XI. Note the balance of - removability and detergent resistance obtained while main-taining a high level of per ormance in other properties.
Table XI
Example 14A 14B 14C
Polish properties Leveling vg-exc. vg vg-exc.
Visual gloss*
one coat g-vg/g g-vg/g-vg. vg/g-vg two coats vg-exc/vg+ exc/vg-exc. vg-exc/exc.
Visual haze nil nil nil Detergent resistance fair vg vg-exc.
Removability good vg-exc. exc.
,.
*Recorded as results on vinyl tile/on OTVA tile see Test Method 3 OI' Table V. A. Example 6.

Claims (20)

CLAIMS:

1. A latex of internally plasticized addition polymer particles, having a calculated Tg above about 20°C, comprising: A) a first stage polymer comprising at least 10% hydrophilic mer units comprising nonionic hydrophilic units and B) a later stage, less hydrophilic, polymer polymerized in the presence of an emulsion of the first stage polymer, wherein the first and later stage polymers are each at least about 20% of the addition polymer, by weight; the latex having (1) a viscosity below about 5,000 centipoises, at 20% solids over the pH range 4 to 10, and (2) a minimum film temperature more than 5°C below the calculated Tg of the addition polymer.

2. The latex of claim 1 in which the viscosity is below 500 centipoises, the Tg is above 30°C, and a film produced from the latex has a Knoop Hardness Number above 5.

3. The latex of claim 2 in which the hydrophilic mer units comprise about 0.5 to 90% acid units and about 99.5% to 10% nonionic units, and the viscosity is below 150 centipoises.

4. The latex of claim 2 in which the hydrophilic mer units comprise about 0.5 to 90% base units and about 99.5% to 10% nonionic units, and the viscosity is below 150 centipoises.

5. The latex of claim 3 in which the viscosity is below 40 centipoises, the minimum film temperature is below 18°C, the Knoop Hardness Number is above 8 and the acid units comprise carboxyl groups.

6. The latex of claim 5 in which the viscosity is below 10 centipoises, and 50 to 90% of the hydrophilic mers are from a hydroxyalkyl ester of an .alpha.,.beta.-unsaturated acid.

7. The latex of claim 6 in which the addition polymer comprises at least one of acrylate, methacrylate, vinyl ester, and vinyl aromatic mer units.

8. The latex of claim 2 in which the first stage polymer comprises 10% to 70% by weight hydrophilic mers and the later stage polymer has a calculated Tg at least 10°C, above the calculated Tg of the first stage polymer;
the polymers of the first and later stage polymers each are at least 30% of the addition polymer weight, and the viscosity of the latex is below 150 centipoises.

9. The latex of claim 8 in which the minimum film temperature is below 18°C, the addition polymer has a Knoop Hardness Number above 5, the calculated Tg of the first stage polymer is below 40°C, and the later stage polymer is harder than the first stage polymer.

10. The latex of claim 9 in which the viscosity is below 40 centipoises, the Knoop Hardness Number above 8, the Tg of the first stage polymer is below 5°C, and the Tg of the later stage polymer is above 75°C..DELTA.

11. The latex or claim 10 in which the viscosity is below 10 centipoises, the polymers of the first and later stages each are at least 40% of the addition polymer, by weight, the Tg of the first stage polymer is below -10°C
and the Tg of the last stage polymer is about 100°C or higher.

12. The latex of claim 11 in which the hydrophilic mers comprise at least 0.5% carboxylic acids and at least 10% nonionic mers.

13. The latex of claim 12 in which the addition polymer is a polymer of monomers comprising at least one of acrylates, methacrylates, vinyl esters and vinyl aromatics.

14. The latex of claim 13 in which the monomers of the first stage comprise 65 to 85% C1-C4 alkyl acrylate, C1-C4 alkyl methacrylate, styrene or a mixture thereof; 5 to 10% acrylic acid, methacrylic acid, itaconic acid or a mixture thereof; and 10 to 25% hydroxy C1-C4 alkyl meth-acrylate, hydroxy C1-C4 alkyl acrylate or a mixture there-of, by weight, and the monomers of the later stage polymer consist essentially of methyl methacrylate, styrene or a mixture thereof.

15. The latex of claim 13 in which the mer units of the first stage comprise 50 to 85% vinyl acetate; 1 to 10%
acrylic, methacrylic, itaconic or maleic acids or a mixture thereof; and 8 to 25% vinyl alcohol, by weight; and the mer units of the later stage consist essentially of methyl methacrylate or styrene mers or a mixture thereof and 0 to 30%, by weight, acidic mers.

16. The latex of claim 15 in which the mer units of the first stage comprise 1 to 4% acid mer units, comprising 0.2 to 2% maleic acid units, 0 to 20% C1-C4 alkyl acrylates,65-80% vinyl acetate and 10 to 20% vinyl alcohol, by weight; and the mer units of the later stage comprise 10 to 20% acid units, by weight.

7. In an aqueous composition adapted to be used for polishing flooring, furniture, and the like, said composition being capable of forming a coating film having a Knoop Hardness Number of at least 0.5 and containing:
(a) 10 to 100 parts by weight of a water-insoluble addition polymer obtained by the emulsion polymerization of at least one ethylenically unsaturated monomer, (b) 0 to 90 parts by weight of an alkali-soluble resin also being up to 90%
by weight, based on the weight of (a), (c) 0 to 90 parts by weight of a wax, (d) wetting, emulsifying and dispersing agents in an amount of 0.5 to 20% by weightof the sum of (a), (b) and (c), (e) at least one polyvalent metal compound in an amount of about 0 to 50% by weight of (a), (f) water to make total solids 0.5 to 45%, the improvement wherein said water-insoluble addition polymer is the internally plasticized addition polymer of claim 1.

18. A process of polishing a hard surface com-prising the steps of coating the surface with the composi-tion of claim 17 and drying the coating.

19. The polished hard surface prepared by the process of claim 18

20. A process, for producing a latex of internally plasticized addition polymer particles, comprising:
(a) polymerizing a first stage polymer comprising at least 10% hydrophilic mer units comprising nonionic hydrophilic units and (b) in the presence of an emulsion of the first stage polymer polymerizing a later stage less hydrophilic polymer wherein the first and later stage polymers are each at least about 20% of the addition polymer, by weight, to produce a latex having (1) a viscosity below about 5,000 centipoises at 20% solids and over the pH range 4 to 10, and (2) a minimum film temperature more than 5 °C below the calculated Tg of the addition polymer;
the addition polymer having a calculated Tg above about 20°C.