WO1995001382A1

WO1995001382A1 - Polymer blends giving high gloss

Info

Publication number: WO1995001382A1
Application number: PCT/US1994/006612
Authority: WO
Inventors: Peter W. Raynolds; Connie A. Sykes
Original assignee: Eastman Chemical Company
Priority date: 1993-06-29
Filing date: 1994-06-13
Publication date: 1995-01-12

Abstract

Disclosed are polymer blends of polyesters or polyesteramides and a styrene polymer. The blends are preferably prepared by polymerizing a styrene monomer in the presence of the polyester or polyesteramide. The blends impart superior gloss and block resistance.

Description

POLYMER BLENDS GIVING HIGH GLOSS

Field of the Invention

The present invention concerns polymer blends of a polyester or polyesteramide and a styrene polymer as well as a process for preparation thereof. These polymer blends impart high gloss to aqueous inks.

Description of the Related Art There continues to be much interest in water- dispersed polymers for inks because of the problems associated with solvent emissions from solvent—based inks.

Certain polyesters are water—dispersible as a result of sulfonate groups on the polyester backbone. These polyesters have been described in, for example, U. S. Patents 3,734,874; 3,546,008 and 3,779,993.

Water—dispersible polyesters have been used in textile sizes and have been used to develop aqueous inks. Inks containing a water—dissipatable polyester are well known in the art as disclosed in U. S. Patents 4,704,309 and 4,738,785. Water-dispersed polyester- polystyrene blends useful as coatings and adhesives have been generally disclosed in U. S. Patents 4,939,233 and 4,946,932. These inks have many desirable features, including excellent gloss and color development, good rewet characteristics, and low odor. However, because of the wide range of printing conditions.and substrates used in the printing industry, a given ink formulation can have ideal properties for some applications and poor properties for other applications. High gloss and block resistance are properties that are highly desirable for many ink applications. It would be highly desirable to have a material that imparts good gloss, and/or block resistance to films prepared from aqueous polyester dispersions while maintaining the other advantages associated with the use of the water—dispersible polyester.

A water-dispersed polyester—polystyrene blend having an additional small amount of "hydrophilic vinyl polymer" is disclosed in Japanese Kokai Patent Application No. Hei 3[1991]—146549. The use of a non- ionic unsaturated polyester as a surfactant in the polymerization of styrene to .obtain a coarse dispersion is disclosed in European Patent Application EP 400,410. A phthalic anhydride-5—sodiosulfoisophthalic acid- tetraethyleneglycol condensation polymer was used as a surfactant and dispersing polymer for dyes (K. M. Chen and H. J. Liu, J. Appl. Poly. Sci., 1987, No. 34, pp. 1879—1888) , and this surfactant was used in an emulsion polymerization with styrene (T. L. McCartney and I. Piirma, Polymer Bull., April 1990, No. 23, pp. 367—371) The need for low—odor, zero—VOC (volatile organic solvent content) emulsion polymers has been described in a review article of new developments in water—borne acrylics for the printing ink industry (H. J. Hartschuh, American Ink Maker, January 1991, pp. 34 ff.). This invention addresses all of these needs, and achieves the desired result with the use of a water—dispersible polyester as both a polymeric surfactant and coalescing aide.

A water dispersible polyester—polystyrene blend derived from polyester containing 4—8 mole % of an unsaturated dicarboxylic acid is described in U. S. Patent 4,119,680.

Summary of the Invention

One object of the present invention is to provide water-dispersed polyester—styrene blends, useful as coatings and inks that exhibit high gloss and excellent heat blocking characteristics.

Another object of the present invention is to provide water-dispersed polyester—styrene blends having low odor levels, and substantially no volatile organic solvent problems.

Yet another object of the present invention is to provide a method of producing the useful polyester— styrene blends of the present invention. Accordingly, one form of the present invention relates to a polymer blend comprising

(A) about 2 weight percent to about 50 weight percent of a water—dispersible sulfonate group—containing polyester or polyester amide comprising; (a) aromatic and aliphatic and ionic dicarboxylic acids such that (i) the mole percent of ionic diacid is about 7 mole percent to about 25 mole percent, and (ii) the mole ratio of aromatic diacids to aliphatic diacids is equal to or greater than 2, (b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexane— dimethanol, 1,3—cyclohexanedi ethanol, and 1,2—cyclohexanedimethanol;

(B) about 50 to about 98 mole percent of a styrene polymer comprising: (a) about 30 to 100 mole percent of repeating units from a styrene compound. Another form of the present invention relates to a polymer blend comprising (A) about 5 weight percent to about 35 weight percent of a water—dispersible sulfonate group—containing ' polyester or polyester amide comprising;

(a) aromatic and aliphatic and ionic dicarboxylic acids such that

(i) the mole percent of ionic diacid is about 7 mole percent to about 25 mole percent, and (ii) the mole ratio of aromatic diacids to aliphatic diacids is equal to or greater than 2,

(b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexane— dimethanol, 1,3—cyclohexanedimethanol, and 1,2—cyclohexanedimethanol;

(B) about 65 to about 95 mole percent of a styrene polymer comprising:

(a) about 30 to 100 mole percent of repeating units from a styrene compound.

Yet another form of the present invention relates o a polymer blend comprising

(A) about 2 mole percent to about 50 mole percent of a water—dispersible sulfonate group—containing polyester or polyester amide comprising;

(a) aromatic and aliphatic and ionic dicarboxylic acids such that

(i) the mole percent of ionic diacid is about 7 mole percent to about 25 mole percent, and

(ii) the mole ratio of aromatic diacids to aliphatic diacids is equal to or greater than 2,

(b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexane¬ dimethanol, 1,3—cyclohexanedimethanol, and 1,2—cyclohexanedimethanol; (B) about 50 to about 98 mole percent of a styrene polymer comprising:

(a) greater than about 50 mole percent of a styrene monomer, and

(b) the balance consisting of repeating units from at least one other -ethylenically unsaturated monomer.

A further form of the invention relates to a method of preparing a water—dispersed polymer blend comprising the steps of

(A) preparing an aqueous polymerization mixture by contacting

(1) a water—dispersible sulfonate group—containing polyester or polyesteramide,

(2) one or more monomers, wherein said monomers comprise: (a) about 50 to about 100 mole percent of a styrene monomer,

(3) a polymerization initiator, and

(4) water,

(B) polymerizing said monomers to provide said water— dispersible polymer blend.

Preferred forms of the invention, as well as other embodiments, objects, features and advantages of this invention, will be apparent from the following detailed description of the present invention.

Description of the Preferred Embodiments of the Invention

Polystyrene is inexpensive. It produces coatings, films and inks. The residual monomer does not have an offensive odor (in contrast to many acrylates) , and glossy films are produced when the latex is applied to a printed surface. One serious deficiency, however, of polystyrene latexes is that they do not form films easily, as a consequence of the high glass transition temperature and brittleness. This is to say that the individual, microscopic polymer particles, when the water is evaporated, do not fuse together to form a strong, continuous sheet of polymer. Instead, they form weak, crumbly, powdery coatings which may often be rubbed off the surface with the finger. Polystyrene may be induced to form film with an additive, such as 2,2,4-trimethyl-l,3—pentanediol— ono(2—methyl- propionate) , that has a low molecular weight and is a good solvent for the polymer. These additives, called coalescing aides, knit the individual particles together by virtue of their action as solvents. Coalescing aides are widely used, but they often have a noticeable odor and contribute to the volatile organic solvent content (VOC) of the coating. It is also possible to improve the film forming properties of polystyrene by copolymerizing it with other monoolefins, especially acrylates, which lower the glass transition temperature. The drawbacks of this technique, which is widely practiced, include (a) strong odor from residual acrylics; (b) decreased gloss; (c) increased tendency of coated surfaces to block (self—stick) , as a consequence of the lower glass transition temperature of the copolymer.

It has now been surprisingly found that a good film forming aide for polystyrene is a brittle, ionic polyester polymer that is immiscible in polystyrene. This finding is contrary to the currently favored technique which depends on finding a good solvent for the polymer. The polyesters used in the present invention on the other hand are not good solvents for polystyrene, yet they aid in film forming.

The polyesters used in this invention are water— dispersible as a result of sulfonate groups on the polyester backbone. Suitable compositions are those described in U. S. Patents 3,734,874; 3,546,008; 4,335,220 and 3,779,993, incorporated herein by reference. Basically, these polyesters and polyester¬ amides are described as having carbonyloxy inter— connecting groups in the linear molecular structure wherein up to 80 percent thereof may be carbonylamido linking groups, the polymer having an inherent viscosity of at least about 0.1, and the polymer consisting essentially of the following components or ester forming or ester—amide forming derivatives thereof;

(a) at least one difunctional dicarboxylic acid;

(b) from about 2 to about 25 mole percent, based on a total of all acid, hydroxy1 and amino equivalents being equal to 200 mole percent, of at least one difunctional sulfomonomer containing at least one metal sulfonate group attached to an aromatic nucleus wherein the functional groups are hydroxy, carboxyl or amino; and

(c) at least one glycol or a mixture of a glycol and a diamine having two —NRH groups, the glycol containing two —OH groups.

Dispersibility is related to the mole percent of sulfomonomer.

The polymer may contain at least one difunctional reactant selected from a hydroxycarboxylic acid having one —CH₂-OH, and aminocarboxylic acid having one — RH group, an amino alcohol having one —CR₂-OH group and one —NRH or mixtures thereof, wherein each R is an H atom or an alkyl group of 1 to 4 carbon atoms. The dicarboxylic acid component of the polyester or polyesteramide comprises aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures of two or more of these acids. Examples of such dicarboxylic acids include succinic; glutaric; adipic; azelaic; sebacic; itaconic; 1,4— cyclohexanedicarboxylic; phthalic; terephthalic and isophthalic.

It is preferred for the"blends of the invention that the aromatic dicarboxylic acids are selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid and mixtures thereof.

It is preferred that the aliphatic dicarboxylic acids useful in the blends of the invention are selected from the group consisting of 1,4—cyclohexanedicarboxylic acid, 1,3—cyclohexanedicarboxylic acid, 1,2— cyclohexanedicarboxylic acid, and mixtures thereof.

It is also preferred that the ionic dicarboxylic acids useful in the blends of the invention are selected from the group consisting of 5—sulfoisophthalic acid, 4— sulfophthalic acid and mixtures thereof.

It should be understood that use of the corresponding acid anhydrides, esters, and acid chlorides of these acids is included in the term "dicarboxylic acid". Other suitable acids are disclosed in U. S. Patent 3,779,993.

The difunctional sulfo—monomer component of the polyester or polyesteramide may advantageously be a dicarboxylic acid or an ester thereof containing a metal sulfonate group or a glycol containing a metal sulfonate group or a hydroxy acid containing a metal sulfonate group. The metal ion of the sulfonate salt may be Na⁺, Li⁺, K⁺ and the like. When a monovalent alkali metal ion is used, the resulting polyesters or polyesteramides are less readily dissipated by cold water and more readily dissipated by hot water. Amines (NH₄Θ, NθR-_L R₂ R₃ R₄) where R=H, alkyl, benzyl, aromatic. When a di¬ valent or a trivalent metal ion is used, the resulting polyesters or polyesteramides are not ordinarily easily dissipated by cold water but are more readily dissipated in hot water. It is possible to prepare the polyester or polyesteramide using, for example, as sodium sulfonate salt and later by ion—exchange replace this ion with a different ion, and thus alter the characteristics of the polymer. The difunctional monomer component may also be referred to as a difunctional sulfomonomer and is further described hereinbelow.

Advantageous difunctional sulfo—monomer components are those wherein the sulfonate salt group is attached to an aromatic acid nucleus such as benzene, naphthalene, diphenyl, oxydiphenyl, sulfonyldiphenyl or methylenediphenyl nucleus. Preferred results are obtained through the use of sodiosulfophthalic acid, sodiosulfoterephthalic acid, sodiosulfoisophthalic acid, 4—sulfonaphthalene-2,7— icarboxylic acid, and their esters; metallosulfoaryl sulfonate as described in U. S. Patent 3,779,993.

Particularly superior results are achieved when the difunctional sulfo—monomer component is 5—sodiosulfo¬ isophthalic acid or its esters and the glycol is a mixture of ethylene glycol or 1,4—cyclohexanedimethanol with diethylene glycol.

When the sulfonate—containing difunctional monomer is an acid or its ester, t a polyester or polyesteramide should contain at least 7 mole percent of said monomer based on total acid content, with more than 11 mole percent giving particularly advantageous results. Total acid content is calculated as the sum of (1) moles of component (a) namely dicarboxylic acids, (2) one-half of the moles of carboxyl—containing compounds of component (d) , (3) moles of component (c) which are dicarboxylic acids, and (4) one—half of the moles of component (c) which are monocarboxy—containing compounds. Useful glycols for preparing copolyesters may consist of aliphatic, alicyclic, and aralkyl glycols. Examples of these glycols include ethylene glycol; propylene glycol; 1,3—propanediol; 2,4—dimethyl—2— ethylhexane—1,3-diol; 2,2-dimethyl-l,3—propanediol; 2-ethyl-2-butyl-l,3-propanediol; 2—ethyl-2-isobutyl-l,3- propanediol; 1,3—butanediol, 1,4—butanediol; 1,5- pentanediol; 1,6—hexanediol; 2,2,4—trimethyl—1,6— hexanediol; thiodiethanol; 1,2—cyclohexanedimethanol; 1,3—cyclohexanedimethanol; 1,4—cyclohexanedimethanol; 2,2,4,4—tetramethy1—1,3—cyclobutanediol; 2,2—dimethyl—3— hydroxypropy1—2,2—dimethyl—3—hydroxypropionate; 2— methyl—1,3—propanediol; and p—xylylenediol. If ethylene glycol is component of the glycol mixtures, superior results are achieved if at least 30% of one other glycol is used.

It is preferable that said glycols are diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexanedimethanol, 1,3—cyclohexanedimethanol, and 1,2—cyclohexanedimethanol. It is also preferable that the remainder of the mole percentage of the total diols is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,5—pentanediol, 1,4— butanediol, 1,3—propanediol, 1,3—cyclobutanediol, 2,2— dimethyl-3-hydroxypropyl-2 ,2-dimethyl-3- hydroxypropionate, butylethylpropanediol and mixtures thereof. Useful polyesters include those wherein the sulfomonomer is a dicarboxylic acid and constitutes about 7 to about 35 mole percent, preferably about 10 to about 25 mole percent based on the sum of (1) the moles of the total dicarboxylic acid content of components (a) and (b) , and (2) one—half of the moles of any hydroxy— carboxylic acid.

Other useful polyesters include those wherein the sulfomonomer is a glycol and -constitutes about 7 mole percent to about 35 mole percent based on the sum of the total glycol content measured in moles of (b) and (c) , and one-half of the moles of any hydroxycarboxylic acid. Thus, a preferred polyester or polyesteramide useful herein comprises a polymer blend wherein said water— dispersible polyester or polyesteramide comprises a polymer having carbonyloxy linking groups in the linear molecular structure wherein up to 80 percent of the linking groups are carbonylamido linking groups, the polymer having an inherent viscosity of from about 0.1 to about 1.0 measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25°C and at a concentration of 0.5 gram of polymer in 100 mL of the solvent, the polymer containing substantially equimolar proportions of acid equivalents (100 mole percent) to hydroxy and amino equivalents (100 mole percent), the polymer comprising the reaction products of reactants selected from (a) , (b) , (c) , and (d) , or the ester forming or esteramide forming derivatives thereof, as follows, wherein all stated mole percentages are based on the total of all acid, hydroxyl, and amino equivalents being equal to 200 mole percent:

(a) at least one difunctional dicarboxylic acid;

(b) from about 7 to about 25 mole percent of at least one difunctional sulfomonomer containing at least one metallic sulfonate group or nitrogen—containing nonmetallic sulfonate group attached to an aromat.-* or cycloaliphatic nucleus wherein the functional groups are hydroxy, carboxyl, or amino;

(c) at least one difunctional reactant selected from a glycol or a mixture of a glycol and dia ine having two —NRH groups, the glycol containing two -OH groups; and

(d) from none to about 40 mole percent of difunctional reactant selected from h^'ydroxycarboxylic acids having one —C(R)₂—OH group, aminocarboxylic acids having one —NRH group, amino—alcohols having one —C(R)₂—OR group and one —NRH group, or mixtures of said difunctional reactants; wherein each R in the (c) and (d) reactants is a hydrogen atom or an alkyl group of 1 to 4 carbons.

It is preferred for the blends of the invention that the aromatic dicarboxylic acids are selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid and mixtures thereof. It is preferred that the aliphatic dicarboxylic acids useful in the blends of the invention are selected from the group consisting of 1,4—cyclohexanedicarboxylic acid, 1,3—cyclohexanedicarboxylic acid, 1,2— cyclohexanedicarboxylic acid, and mixtures thereof. It is also preferred that the ionic dicarboxylic acids useful in the blends of the invention are selected from the group consisting of 5—sulfoisophthalic acid, 4- sulfophthalic acid and mixtures thereof.

More preferably the polyester has an inherent viscosity of from about 0.1 to 0.4, 9-18 mole percent of sodium 5—sulfoisophthalic acid as the ionic monomer, less than 30 mole percent of an aromatic diacid such as isophthalic acid.

Even more preferably, the polyester has an IV of 0.2 - 0.4, contains 11% sodium 5-sulfoisophthalate, 89% dimethyl cyclohexanedicarboxylate, and the glycol is 100% 2,2—dimethyl-l,3—propanediol.

In another preferred embodiment, the polyester has an inherent viscosity of from about 0.20 to about 0.38, an acid moiety of from about 75 to about 92 mole percent isophthalic acid and/or terephthalic acid and conversely from about 25 to about 18 mole percent 5—sodiosulfo— isophthalic acid, and a glycol moiety of from about 75 to about 100 mole percent diethylene glycol and conversely from about 0 to about 25 mole percent

1,4-cyclohexanedimethanol, or 1,3—cyclohexanedimethanol, or 1,2—cyclohexanedimethanol, or mixtures thereof.

Further, it is preferred that the polyester comprises an acid moiety comprising from about 80 to about 92 mole percent isophthalic acid and conversely from about 20 to about 8 mole percent 5— sodiosulfoisophthalic acid, and said glycol moiety comprises from about 75 to about 100 mole percent diethylene glycol and, conversely, from about 0—25 mole percent 1,4—cyclohexanedimethanol, or 1,3—cyclohexane¬ dimethanol, or 1,2—cyclohexanedimethanol, or mixtures thereof, and from 0-30 mole % of ethylene glycol.

The styrene monomer useful herein is preferably of the structure

wherein R¹ is H or methyl, R² is a lower alkyl group of 1 to 6 carbon atoms, and m is an integer of 0 to 2. Preferably m is 0 or 1, and R² is methyl, and R¹ is H.

The most preferable styrene monomers are styrene, α—methyl styrene, 4-methyl styrene, 3—methyl styrene, t—butyl styrene, and mixtures thereof.

The meth(aerylate) monomer useful herein preferably is of the structure

COO ³

CH₂:

R

wherein R³ is H or an alkyl group of 1 to 10 carbon atoms, optionally substituted with one or two substituents selected from the group consisting of C^—C₆ alkoxy, hydroxy, epoxy, acetoacetoxy and halogen, and R¹ has the same meaning as previously defined.

It is also preferred that the (meth)aerylate monomer of component (B) of this invention comprise repeating units selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N- methylolacrylonitrile, N-methylolacrylamide, N- ethylacrylamide, methyl aerylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl aerylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2—ethylhexyl acrylate, 2—ethylhexyl methacrylate, stearyl acrylate. stearyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2—ethoxyethyl acrylate, 2— ethoxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, a diol acrylate, a diol methacrylate, and mixtures thereof.

Preferably, the (meth)acrylate monomer is selected from the group consisting of butyl acrylate, ethyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, glycidyl (meth)acrylate, acetoacetoxyethyl methacrylate, hydroxyethyl acrylate and mixtures thereof.

It is also preferred that component (B) further comprises repeating units from acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N—methylolacrylonitrile, N— methylolacrylamide, N—methylacrylamide, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n—propyl acrylate, n—propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n—butyl acrylate, n- butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, stearyl acrylate, stearyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2— ethoxyethyl acrylate, 2—ethoxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, a diol acrylate, a diol methacrylate, and mixtures thereof.

It is also preferred that component (B) of the invention, the styrene polymer, comprise up to about 70 wt. percent of repeating units from a compound selected from the group consisting of (meth)acrylate compounds, sodium 2-acrylamido-2-methyl-l-propanesulfonate, ammonium 2—aerylamide—2— ethyl—1—propanesulfonate, potassium 2—acrylamido—2—methyl—1—propanesulfonate, lithium 2—acrylamido—2—methyl—1—propanesulfonate, sodium 2—acrylamido—2-methy1—1—propanesulfonate, and mixtures thereof.

The polymer blends may comprise additives other than coalescing aids, as previously mentioned in the amount of 0.1 to 5.0 weight percent of the total composition. These additives^' may be surfactants, chain transfer agents, alcohols, antifoams, and combinations thereof.

The surfactants useful in the invention include anionic and nonionic surfactants. Preferred nonionic surfactants include nonylphenol ethoxylate, nonylphenoxypoly(ethyleneoxy)ethanol, and one or more block copolymers of propylene oxide and ethylene oxide.

In the process of the present invention, the monomers are polymerized in the presence of the sulfonate—group containing polymer (i.e., the polyester or polyesteramide) .

In the method of the present invention, the polymer blends of the present invention are prepared in aqueous dispersions. The monomers are generally added to an aqueous dispersion of the water-dispersible polyester and polymerized by free radical initiation in conventional emulsion or suspension polymerization processes. The preferred ratio of polyester to monomer will vary widely and depends on the intended application for the blend. The polymerization can be initiated by a water- soluble free radical initiator known in the art such as sodium or potassium persulfate or by an oil—soluble initiator such as AIBN or benzoyl peroxide. Other useful initiators include redox initiators such as sodium persulfate/sodium metabisulfite and sodium formaldehyde sulfoxylate/Fe/hydrogen peroxide.

A typical temperature range for the polymerization reaction is about 20°C to about 90°C with about 60°C to about 85°C being preferred.

The sulfonate—group containing polymers which are used in the present invention typically become very viscous at concentrations above about 34 percent total solids. Thus, the reaction typically is begun with a polyester or polyesteramide dispersion that is about 30 percent total solids or less. However, the dispersions are prepared at final total solids levels up to from about 20 percent to about 60 percent. A total solids content of about 35 percent to about 50 percent is preferred. The increase in solids level is achieved during polymerization by controlling the amount of water, if any, which is added along with the monomer. Thus, the method of the present invention for preparing water dispersed polymer blends can be described as comprising the steps of:

(A) preparing an aqueous polymerization mixture by contacting

(1) a water—dispersible sulfonate group—containing polyester or polyesteramide, (2) one or more monomers, wherein said monomers comprise:

(a) about 50 to about 100 mole percent of a styrene monomer, (3) a polymerization initiator, and (4) water,

(B) polymerizing said monomers to provide said water- dispersible polymer blend.

In the polymerization method, it is preferred that component (A) is present in an amount of about 0.7 — 25 weight percent, and component (B) is present in an amount of about 17.5 — 49 weight percent.

It is also preferred that the polymerization mixture contain up to 20 weight percent of a C_λ to C₄ alcohol, especially propanol. Lesser amounts of the alcohol (e.g. , up to 5 or 10 weight percent) can be employed. It has been found that use of the alcohol results in unexpected advantages in the polymerization reaction, especially achieving smaller particle size. It is anticipated that smaller particle size leads to improved dispersion stability and possible improved film-forming properties. In the polymerization method of the invention, more preferred is wherein component (A) is present in an amount of about 0.7 — 25 weight percent, component (B) is present in an amount of about 17.5 — 49 weight percent, and the alcohol is present in an amount of up to 10 weight percent. Even more preferred is wherein component (A) is present in an amount of about 2.0 — 15.8 weight percent, component (B) is present in an amount of about 26 — 42.8 weight percent, and the alcohol is present in an amount of up to 5 weight percent.

The method of the present invention produces polymer blends which are significantly different than mere physical mixing of two preformed polymers. For example, the blends produced by the invention method have monodisperse or monomodal particle size distributions. The particle size distribution of the blends produced by the method of the invention preferably has an average particle size diameter of about 40 to about 300 nanometers (nm) . Additionally, since the polyester acts as all or part of the surfactant needed to produce stable polystyrene latex, additional surfactants would have to be added to a polystyrene latex if it were prepared separately. These added surfactants could lead to increased cost and inferior performance.

In a preferred embodiment, the sulfonate group- containing polymer is prepared, generally by melt polymerization, and an aqueous dispersion containing from about 10 percent to about 30 percent total solids is prepared from the polyester or polyesteramide directly. A mixture of one or more monomers and the polymerization initiators may then be added to the aqueous dispersion of the polyester or polyesteramide and polymerization initiated to produce an aqueous dispersion. The aqueous dispersion so produced can be prepared with total solids contents from about 20 percent to about 60 percent. Preferably, the pH is, or is adjusted to be, within the range of about 4—8 in order to minimize hydrolysis of the polyester.

The invention can be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for the purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated. All percentages are by weight, unless otherwise specified.

As used herein, the term "I.V." is inherent viscosity measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25°C and at a concentration of 0.5 gram of polymer in 100 mL of the solvent. Also, as used herein, the term "NVM" means non—volatile matter, determined by evaporating the dispersion at 120°F for 16 hours. EXAMPLES

EXAMPLE 1

The polyester was composed of 72 mole percent terephthalic acid, 15 mole percent isophthalic acid, and 13 percent 5—sodiosulfoisophthalic acid. The diols consisted of 53 mole percent ethylene glycol, 32 mole percent diethylene glycol, and 15 mole percent triethylene glycol. The polyester had a glass transition temperature of 49°C, an I.V. of 0.464 and an acid number of 5.1. The polymer was dispersed in water, giving a translucent dispersion, 30.12 percent NVM (non¬ volatile matter, determined by evaporating the dispersion at 120° F for 16 hours), with a pH of 5.36, a viscosity of 232 cps.

The reactor was a fully jacketed, 1 liter round bottom 3—neck flask with Morton indentations. The flask was equipped with a mechanical stirrer (100—400 rpm) , thermometer, nitrogen inlet and condenser. Reactions were run under a blanket of nitrogen, but neither the contents of the reactor nor the material to be added to the reactor were sparged with nitrogen. Temperature was maintained with circulating hot water. Material was pumped into the reactor through polytetrafluoroethylene tubing with a positive displacement metering pump with stainless steel/graphite heads.

A catalyst solution was made from 0.5 g of ammonium persulfate and 25 g of water. An emulsion was formed by hand shaking a mixture of 150 g of deionized water, 0.2 g of sodium carbonate, 18 g of the catalyst solution, 81 g of the polyester dispersion mentioned above, 6.0 g of surfactant comprising a 75 percent solution of sodium dioctylsulfosuccinate in ethanol—water and 199 g of styrene. The reactor was charged with the remainder of the catalyst solution, 37 g of water and 9 g of the polyester dispersion. The reactor was heated to 75°C ^•.^■ and the emulsion was pumped into the reactor over 2 hours. The mixture was heated 2 additional hours at 80°C, cooled and filtered through a 110 micron polyethylene mesh.

The weight ratio of polyester to polystyrene was 12:88 by formulation. The latex had 44.88 percent NVM, pH = 6.24, viscosity = 46 cps, acid number — 2, particle size = 178 nm. The 'dried polymer residue had an IV of 1.140 dL g, Tg = 39, 108°C. The product was stable for one week at 50°C and passed one freeze-thaw cycle. When drawn down as a thin film over 55 pound clay coated paper printed with a red ink, the gloss, without additives, was 50 percent at a 60° angle and the film was clear and free from haze or opalescence.

EXAMPLE 2

The polyester was composed of 89 mole percent isophthalic acid and 11 mole percent 5—sodiosulfo- isophthalic acid. The diol consisted of diethylene glycol, along with percent amounts (approximately 1 percent) of ethylene glycol and triethylene glycol that are normally generated from diethylene glycol in a side reaction in the production process. The polyester had a glass transition temperature of 29°C. The polymer was dispersed in water containing 0.15 weight percent anhydrous sodium acetate, giving a white dispersion, 29.87 percent NVM, with a pH of 5.36, and a viscosity of 232 cps. The experimental apparatus is described in

Example 1; the reactor had a capacity of 2 liters. A catalyst solution" was made from 1.5 g of ammonium persulfate and 75 g of water. An emulsion was formed by hand—shaking 194 g of water, 0.6 g of sodium carbonate, 53.5 g of the catalyst solution, 651 g of the polyester dispersion described above, and 300 g of styrene. The. reactor was charged with 72 g of the polyester dispersion, 49 g of water and the remainder of the catalyst solution. It was heated to 75°C and the emulsion was added over 2.5 hours. The reactor was heated an additional two hours, cooled, and the opaque white product was filtered.

The weight ratio of polyester to polystyrene was

32:68 by formulation. The latex had 44.66 percent NVM, pH = 6.45, viscosity = 91 cps, acid number = 2, particle size = 122 nm. The dried polymer residue had an IV dL/g of 0.608, Tg = 29°C, and had 260 ppm residual styrene.

The product was stable for one week at 50°C. When drawn down as a thin film over 55 pound clay coated paper printed with red ink, the gloss, without additives, was

67 percent and the film was clear and free from haze or opalescence.

EXAMPLE 3 The polyester was composed of 89 mole percent isophthalic acid and 11 mole percent 5—sodiosulfo— isophthalic acid. The diol consisted of 28 mole percent ethylene glycol and 72 mole percent diethylene glycol. The polyester had a glass transition temperature of 43°C. The polymer was dispersed in water containing

0.15 weight percent anhydrous sodium acetate, giving a white dispersion, 29.99 percent NVM, with a viscosity of 232 cps.

The experimental apparatus is as described in Example 2.

A catalyst solution was made from 1.5 g of ammonium persulfate and 75 g of water. An emulsion was formed by hand—shaking 191 g of water, 0.6 g of sodium carbonate, 53.5 g of acrylamido-2-methylpropanesulfonate (AMPS) in water, 648 g of the polyester dispersion described above, and 452 g of styrene. The reactor was charged with 72 g of the polyester dispersion, 48 g of water and the remainder of the catalyst solution. It was heated to.75°C and the emulsion was added over 2.5 hours. The reactor was heated an additional 2 hours, cooled, and the opaque white product was filtered.

The weight ratio of polyester to polystyrene to AMPS was 32:67:1 by formulation. The latex had 44.66 percent NVM, pH ~= 6.45, viscosity = 91 cps, acid number = 2, particle size = 122 n . The dried polymer residue had an IV of 0.608 dL/g, Tg = 29°C, and contained 260 pp residual styrene. The product was stable for one week at 50°C. When drawn down as a thin film over 55 pound clay coated paper printed with red ink, the gloss, without additives, was 67 percent and the film was clear and free from haze or opalescence.

EXAMPLE 4

The polyester and experimental apparatus were as described in Example 2.

A catalyst solution was made from 1.5 g of ammonium persulfate and 75 g of water. An emulsion was formed by hand shaking 499 g of water, 0.6 g of sodium carbonate, 53.5 g of the catalyst solution, 18 g of OT-75 surfactant comprising a 75 percent solution of sodium dioctylsulfosuccinate in ethanol—water and 199 g of styrene, 163 g of the polyester dispersion described in Example 2, and 621 g of styrene. The reactor was charged with 18 g of the polyester dispersion, 125 g of water and the remainder of the catalyst solution. It was heated to 75°C and emulsion was added over 2.5 •hours. The reactor was heated a additional 2 hours, cooled, and the opaque white product was filtered.

The weight ratio of polyester to polystyrene was 8:92 by formulation. The latex had 45.72 percent NVM, pH = 7.10, viscosity = 22 cps, particle size = 152 nm. \ The dried polymer residue had an IV of 0.989 dL g, Tg = 29 and 105°C, and contained greater than ppm residual styrene. The product was stable for one week at 50°C. When drawn down as a thin film over 55 pound clay coated paper printed with red ink, the gloss, without additives, was 61 percent and the film was clear and substantially free from haze or opalescence.

EXAMPLE 5

Following the method of Example 4, the ratio of polyester to polystyrene was varied, and the results were collected in Table 1. At polyester levels below about 28 percent, it was found that an anionic surfactant, dioctylsulfosuccinate (DOSS) was useful in obtaining latexes with a small particle size that would filter readily.

Table 1

EXAMPLE 6

A water dispersible polyester was prepared with a composition, by formulation, of 74 mole percent isophthalic acid, 20 mole percent adipic acid, and 6 mole percent 5-sodiosulfoisophthalic acid. The glycol was diethylene glycol. The polyester was dispersed in water containing 0.1 percent anhydrous sodium acetate but no added solvent to give a dispersion with a viscosity of 16 cps, containing 30.15 percent NVM. A latex was prepared by the general procedure described in Example 5, giving a white latex.

The latex had a composition of 10 percent polyester and 90 percent polystyrene. Dioctylsulfosuccinate, 2 percent based on the total dry polymer weight, had been added during the polymerization to give a product with a low particle size. The gloss of the unformulated latex was 50 percent.

EXAMPLE 7 The polyester and experimental apparatus were the same as in Example 2. A catalyst solution was made from 1.5 g of ammonium persulfate and 75 g of water. An emulsion was formed by hand shaking a mixture of 454 g of deionized water, 0.6 g of sodium carbonate, 54 g of the catalyst solution, 237 g of a 30.70 percent NVM dispersion of the polyester of Example 2, 18 g of OT-75 surfactant, 297 g of methyl methacrylate and 297 g of styrene. The reactor was charged with the remainder of the catalyst solution, 113 g of water and 26 g of the polyester dispersion. The reactor was heated to 75^βC and the emulsion was pumped into the reactor over 2.5 hours. The mixture was heated 2 additional hours at 80°C, cooled and filtered through a 110 micron polyethylene mesh. The weight ratio of polyester to polystyrene to methyl methacrylate was 12:44:44 by formulation, and the amount of sodium dioctylsulfosuccinate was 2 percent based on the total dry polymer weight. The latex had 44.24 percent NVM, pH = 6.93, viscosity = 35 cps, particle size = 104 nm. The dried polymer residue had an IV of 1.385 dL/g, Tg = 33, 106°C. The product was stable for one week at 50°C. When drawn down as a thin film over 55 pound clay coated paper printed with a solid red ink, the gloss, without additives, was 48 percent at a 60° angle and the film was clear and free from haze or opalescence.

EXAMPLE 8 In a reaction similar to Example 7, a latex was prepared wherein the olefinic monomer was entirely methyl methacrylate; styrene was not used. The weight ration of polyester to poly(methyl methacrylate) was 16:84, and 2 percent dioctylsulfosuccinate was used. The particle size was 86 nm, the pH was 6.82, and the latex contained 45.29 percent NVM. The gloss was 30 percent.

EXAMPLE 9 .Comparative Example) — Preparation of the Polyester

The water-dispersible polyester had a composition, by formulation, of 65% adipic acid, 22% isophthalic acid and 13% 5-sodiosulfoisophthalic acid. The glycol was diethylene glycol, which, under the reaction conditions, was converted to a mixture of ethylene glycol, di— and triethylene glycol by an acid catalyzed side reaction. Triethylene glycol was not observed directly because it was not be resolved from the adipic acid by the analytical procedure, but its presence is inferred by experience with similar reactions. A one liter round bottom 3—neck flask equipped with a mechanical stirrer, thermometer, distillation head and heating mantle controlled by a thermocouple controller was charged with 219 g of adipic acid, 83 g of isophthalic acid, 283 g of a 47% solution of the bis(diethyleneglycolJester of

5-sodiosulfoisophthalic acid in diethylene glycol, 200 g of diethylene glycol, 0.1 g of sodium acetate and 1 g of a solution of titanium isopropoxide catalyst in n-propanol, containing 1.58% -titanium by weight. The polyester was formed by the general procedure described in Example 1. The product, a slightly flexible solid, had an acid number of 0.9, a weight average molecular weight of 8900 by gel permeation chromatography, an IV of 0.233 dL/g, a ratio of ethylene glycol to diethylene glycol of 25:75 (triethylene glycol, if present, was obscured by the adipic acid); sulfur content = 1.51%. The differential scanning calorimetry analysis showed no distinct and reproducible transitions. The product dispersed readily in water containing 0.05% sodium carbonate to give a crystal clear solution, which was adjusted to a pH of 5.94, 34.63% NVM.

Preparation of the Polyester—Polystyrene Blend by Emulsion Polymerization The general procedure described in Example 1 was used. A catalyst solution was made from 1.0 g of ammonium persulfate and 50 g of water. An emulsion was formed by hand shaking a mixture of 258 g of deionized water, 0.4 g of sodium carbonate, 36 g of the catalyst solution, 312 g of the 34.63% NVM polyester dispersion mentioned above, and 280 g of styrene. The reactor was charged with the remainder of the catalyst solution, 60 g of water and 35 g of the polyester dispersion. The reactor was heated to 75°C and the emulsion was pumped into the reactor over 2.5 hours. The mixture was heated 2 additional hours at 80°C, cooled and filtered through a 110 micron polyethylene mesh.

The weight ratio of polyester to polystyrene was 30:70 by formulation. No added surfactant or solvent was used. The latex had 40.08% NVM, pH = 5.41, viscosity = 27 cps, particle diameter = 57 nm. The dried polymer residue had an IV of 0.969 dL/g, Tg = 107°C. When drawn down as a thin film over 55 pound clay coated paper printed with a solid red ink, the gloss, without additives, was 30% and the blocking temperature was 200°F (93°C).

The invention has been described in detail with particular reference to the preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. Moreover, all patents, patent applications (published or unpublished, foreign or domestic) , literature references or other publications noted above are incorporated herein by reference for any disclosure pertinent to the practice of this invention.

Claims

CLAIMS We claim:

1. A polymer blend comprising:

(A) about 2 wt. percent to about 50 wt. percent of a water-dispersible sulfonate group-containing polyester or polyester amide comprising;

(a) aromatic and aliphatic and ionic dicarboxylic acids such that

(i) the mole -percent of ionic diacid is about 7 mole percent to about 25 mole percent of the total diacids, and (ii) the mole ratio of aromatic diacids to aliphatic diacids is equal to or greater than 2,

(b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexanedimethanol, 1,3—cycle— hexanedimethanol, and 1,2—cyclohexane¬ dimethanol;

(B) about 50 to about 98 wt. percent of a styrene polymer comprising:

(a) about 30 to 100 wt. percent of repeating units from a styrene compound.

2. The polymer blend as claimed in Claim 1 wherein, the styrene compound in component (B) is selected from the group consisting of styrene, α—methyl styrene, 3—methyl styrene, 4—methyl styrene, t—butyl styrene, and mixtures thereof.

3. The polymer blend as claimed in Claim 1 wherein, component (B) comprises: (a) about 30 to 100 wt. percent of repeating units from a styrene compound, and

(b) up to about 70 wt. percent of repeating units from a compound selected from the group consisting of (meth)acrylate compounds, sodium

2—acrylamido—2—methyl—1—propanesulfonate, ammonium 2—acrylamido—2—methyl—1—propane¬ sulfonate, potassium 2—acrylamido—2—methyl—1- propanesulfonate, lithium 2—acrylamido—2- methyl-1-propanesulfonate, sodium

2-acrylamido-2—methy1-1—propanesulfonate, and mixtures thereof.

4. The polymer blend as claimed in Claim 3 wherein, component (B) (a) is selected from the group consisting of styrene, α—methyl styrene, 3—methyl styrene, 4—methyl styrene, t—butyl styrene, and mixtures thereof, and component (B) (b) is selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N—methylolacrylo¬ nitrile, N—methylolacrylamide, N—methylacrylamide, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n—propyl acrylate, n—propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n—butyl acrylate, n—butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2—ethylhexyl acrylate, 2—ethylhexyl methacrylate, stearyl acrylate, stearyl meth- acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2—ethoxyethyl acrylate, 2—ethoxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, a diol acrylate, a diol methacrylate, and mixtures thereof.

5. The polymer blend as claimed in Claim 1 wherein, said polymer blend also contains additives.

6. The polymer blend as claimed in Claim 5 wherein, said additives are selected from the group consisting of surfactants, chain transfer agents, alcohols, anti—foams, coalescing aides, and combinations thereof.

7. The polymer blend of Claim 1 wherein, said (A) water-dispersible polyester or polyesteramide comprises a polymer having carbonyloxy linking groups in the linear molecular structure wherein up to 80 percent of the linking groups are carbonylamido linking groups, the polymer having an inherent viscosity of from about 0.1 to about 1.0 measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25°C and at a concentration of 0.5 gram of polymer in 100 mL of the solvent, the polymer containing substantially equimolar proportions of acid equivalents (100 mole %) to hydroxy and amino equivalents (100 mole %) , the polymer comprising the reaction products of reactants selected from (a) , (b) , (c) , and (d) , or the ester forming or esteramide forming derivatives thereof, as follows, wherein all stated mole percentages are based on the total of all acid, hydroxyl, and amino equivalents being equal to 200 mole percent: (a) at least one difunctional dicarboxylic acid; (b) from about 7 to about 25 mole percent of at least one difunctional sulfomonomer containing at least one metallic sulfonate group or nitrogen—containing nonmetallic sulfonate group attached to an aromatic or cycloaliphatic nucleus wherein the functional groups are hydroxy, carboxyl, or amino; (c) at least one difunctional reactant selected from a glycol or a mixture of a glycol and dia ine having two —NRH groups, the glycol containing two -OH groups; and (d) from 0 to about 40 mole percent of difunctional reactant selected from hydroxycarboxylic acids having one —C(R)₂—OH group, aminocarboxylic acids having one —NRH group, amino—alcohols having one —C(R)₂—OH group and one —NRH group, or mixtures of said difunctional reactants; wherein each R in the (c) and (d) reactants is a hydrogen atom or an alkyl group of 1 to 4 carbons;

(B) said styrene compound is of the structure

wherein R¹ is H or methyl, R² is a lower alkyl group of 1 to 6 carbon atoms, and m is an integer of 0 to 2.

8. The polymer blend as claimed in Claim 1 wherein,

(a) the aromatic dicarboxylic acids are selected ^' from the group consisting of terephthalic acid, isophthalic acid, phthalic acid and mixtures thereof;

(b) the aliphatic dicarboxylic acids are selected from the group consisting of 1,4—cyclohexane¬ dicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2—cyclohexanedicarboxylic acid, and mixtures thereof,

(c) the ionic dicarboxylic acids are selected from the group consisting of 5—sulfoisophthalic acid, 4—sulfophthalic acid and mixtures thereof, (d) no more than about 50 mole % of the diols being selected from diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexanedimethanol, 1,3—cyclohexane— dimethanol, and 1,2—cyclohexanedimethanol, and

(e) the remainder being selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,5—pentanediol, 1,4—butane¬ diol, 1,3—propanediol, 1,3—cyclobutanediol, 2,2—dimethyl—3—hydroxypropy1—2,2-dimethyl—3- hydroxypropionate, butylethylpropanediol and mixtures thereof.

9. A polymer blend comprising:

(A) about 5 wt. percent to about 35 wt. percent of a water-dispersible sulfonate group-containing polyester or polyester amide comprising; (a) aromatic and aliphatic and ionic dicarboxylic acids such that

(b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexanedimethanol, 1,3—cyclo¬ hexanedimethanol, and 1,2—cyclohexane¬ dimethanol; (B) about 65 to about 95 wt. percent of a styrene polymer comprising:

(a) about 30 to 100 wt. percent of repeating units from a styrene compound.

10. The polymer blend as claimed in Claim 9 wherein, the styrene compound in component (B) is selected from the group consisting of styrene, α—methyl styrene, 3—methyl styrene, 4—methyl styrene, t—butyl styrene, and mixtures thereof.

11. The polymer blend as claimed in Claim 9 wherein, component (B) comprises:

(a) about 30 to 100 wt. percent of repeating units from a styrene compound, and (b) up to about 70 wt. percent of repeating units from a compound selected from the group consisting of (meth)acrylate compounds, sodium 2—acrylamido—2—methyl—1—propanesulfonate, ammonium 2—acrylamido—2—methyl—1—propane— sulfonate, potassium 2—acrylamido—2—methyl—1— propanesulfonate, lithium 2—acrylamido—2- methy1-1—propanesulfonate, sodium 2—aerylamide—2—methy1-1—propanesulfonate, and mixtures thereof.

12. The polymer blend of Claim 11 wherein, said (A) water-dispersible polyester or polyesteramide comprises a polymer having carbonyloxy linking groups in the linear molecular structure wherein up to 80 percent of the linking groups are carbonyl¬ amido linking groups, the polymer having an inherent viscosity of from about 0.1 to about 1.0 measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25°C and at a concentration of 0.5 gram of polymer in 100 mL of the solvent, the polymer containing substantially equimolar proportions of acid equivalents (100 mole %) to hydroxy and amino equivalents (100 mole %) , the polymer comprising the reaction, products of reactants selected from (a) , (b) , (c) , and (d) , or the ester forming or esteramide forming derivatives thereof, as follows, wherein all stated mole percentages are based on the total of all acid, hydroxyl, and amino equivalents being equal to 200 mole percent:

(a) at least one difunctional dicarboxylic acid;

(b) from about 7 to about 25 mole percent of at least one difunctional sulfomonomer containing at least one metallic sulfonate group or nitrogen-containing nonmetallic sulfonate group attached to an aromatic or cycloaliphatic nucleus wherein the functional groups are hydroxy, carboxyl, or amino;

(c) at least one difunctional reactant selected from a glycol or a mixture of a glycol and diamine having two —NRH groups, the glycol containing two —OH groups; and

(d) from 0 to about 40 mole percent of difunctional reactant selected from hydroxycarboxylic acids having one —C(R)₂-OH group, aminocarboxylic acids having one —NRH group, a ino-alcohols having one —C(R)₂-OH group and one —NRH group, or mixtures of said difunctional reactants; wherein each R in the (c) and (d) reactants is a hydrogen atom or an alkyl group of 1 to 4 carbons;

(B) said styrene compound is of the structure

wherein R¹ is H or methyl, R² is a lower alkyl group of 1 to 6 carbon atoms, and m is an integer of 0 to 2; and (C) said (meth)acrylic compound is of the structure

CH,

wherein R³ is H or an alkyl group of 1 to 10 ■ carbon atoms, optionally substituted with one or two substituents selected from the group consisting of hydroxy, acetoacetoxy, C_x—C₆ alkoxy, epoxy and halogen, and R¹ is hydrogen or methyl.

13. The polymer blend as claimed in Claim 1 wherein, component (B) comprises: (a) about 30 to 100 wt. percent of repeating units from a styrene compound selected from the group consisting of styrene, a— ethyl styrene, 3—methyl styrene, 4—methyl styrene, t—butyl styrene, and mixtures thereof, and (b) up to about 70 wt. percent of repeating units from a compound selected from the group consisting of (meth)acrylate compounds, acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile , acrylamide, .methacrylamide, N—methylolacrylonitrile, N—methylolacrylamide,

N—methylacrylamide, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n—propyl acrylate, n—propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n—butyl acrylate, n—butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2—ethylhexyl acrylate, 2—ethylhexyl methacrylate, stearyl acrylate, stearyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2—ethoxyethyl acrylate, 2—ethoxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, aceto¬ acetoxyethyl acrylate, acetoacetoxyethyl methacrylate, a diol acrylate, a diol methacrylate sodium 2—acrylamido-2-methyl—1- propanesulfonate, ammonium 2—acrylamido—2— methy1—1—propanesulfonate, potassium 2—acrylamido—2—methyl—1—propanesulfonate, lithium 2—acrylamido—2-methy1—1—propane¬ sulfonate, sodium 2—acrylamido—2—methyl—1— propane amine, and mixtures thereof.

14. The polymer blend as claimed in Claim 9 wherein, said polymer blend also -contains additives.

15. The polymer blend as claimed in Claim 14 wherein, said additives are selected from the group consisting of surfactants, chain transfer agents, alcohols, anti—foams, coalescing aids, and combinations thereof.

16. The polymer blend as claimed in Claim 9 wherein,

(a) the aromatic dicarboxylic acids are selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid and mixtures thereof;

(b) the aliphatic dicarboxylic acids are selected from the group consisting of 1,4—cyclohexane¬ dicarboxylic acid, 1,3—cyclohexanedicarboxylic acid, 1,2—cyclohexanedicarboxylic acid, and mixtures thereof,

(c) the ionic dicarboxylic acids are selected from the group consisting of 5—sulfoisophthalic acid, 4—sulfophthalic acid and mixtures thereof,

(d) no more than about 50 mole % of the diols being selected from diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4-cyclohexanedimethanol, 1, 3-cyclohexane- dimethanol, and 1,2-cyclohexanedimethanol, and (e) the remainder being selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,5-pentanediol, 1,4—butane¬ diol, 1,3-propanediol, 1,3—cyclobutanediol, 2,2-dimethyl-3-hydroxypropyl-2,2-dimethyl-3- hydroxypropionate, butylethylpropanediol and mixtures thereof.

17. A polymer blend comprising:

(A) about 2 wt. percent to about 50 wt. percent of a water-dispersible sulfonate group—containing polyester or polyester amide comprising; (a) aromatic and aliphatic and ionic dicarboxylic acids such that (i) the mole percent of ionic diacid is about 7 mole percent to about 25 mole percent, and (ii) the mole ratio of aromatic diacids to aliphatic diacids is equal to or greater than 2, (b) diols comprising no more than about 50 mole percent of the total diols being selected from the group consisting of 1,4—cyclohexanedimethanol, 1,3—cyclo¬ hexanedimethanol, and 1,2—cyclohexane— dimethanol;

(B) about 50 to about 98 wt. percent of a styrene polymer -comprising:

(a) greater than about 50 wt. percent of a styrene monomer, and (b) the balance consisting of repeating units from at least one other ethylenically unsaturated monomer.

18. The polymer blend as claimed in Claim 17 wherein, component (B) (a) is selected from the group consisting of styrene, α—methyl styrene, 3—methyl styrene, 4—methyl styrene, t—butyl styrene, and mixtures thereof, and co^'mponent (B) (b) is selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N—methylolacrylo— nitrile, N—methylolacrylamide, N—methylacrylamide, methyl acrylate methyl methacrylate, ethyl acrylate, ethyl methacrylate, n—propyl acrylate, n—propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n—butyl acrylate, n—butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, 2—ethylhexyl acrylate, 2—ethylhexyl methacrylate, stearyl acrylate, stearyl meth¬ acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, 2—ethoxyethyl acrylate, 2—ethoxyethyl methacrylate, glycidyl acrylate, glycidyl meth¬ acrylate, acetoacetoxyethyl acrylate, aceto— acetoxyethyl methacrylate, a diol acrylate, a diol methacrylate, vinyl acetate, vinylidene chloride, butadiene, 1—methylbutadiene, 2—methylbutadiene, 2—chloro—butadiene, diisobutylene, cyclopentadiene, divinylbenzene, diallylphthalate, and mixtures thereof.

19. The polymer blend of Claim 17 wherein, said (A) water-dispersible polyester or polyesteramide comprises a polymer having carbonyloxy linking groups in the linear molecular structure wherein up to 80 percent of the linking groups are carbonyl¬ amido linking groups, the polymer having an inherent viscosity of from about 0.1 to about 1.0 measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25°C and at a concentration of 0.5 gram of polymer in 100 mL of the solvent, the polymer containing substantially equimolar proportions of acid equivalents (100 mole %) to hydroxy and amino equivalents (100 mole %) , the polymer comprising the reaction products of reactants selected from (a) , (b) , (c) , and (d) , or the ester forming or esteramide forming derivatives thereof, as follows, wherein all stated mole percentages are based on the total of all acid, hydroxyl, and amino equivalents being equal to 200_. mole percent:

(a) at least one difunctional dicarboxylic acid;

(b) from about 4 to about 25 mole percent of at least one difunctional sulfomonomer containing at least one metallic sulfonate group or nitrogen—containing nonmetallic sulfonate group attached to an aromatic or cycloaliphatic nucleus wherein the functional groups are hydroxy, carboxyl, or amino;

(c) at least one difunctional reactant selected from a glycol or a mixture of a glycol and diamine having two —NRH groups, the glycol containing two -OH groups; and

(d) from 0 to about 40 mole percent of difunctional reactant selected from hydroxycarboxylic acids having one —C(R)₂-OH group, aminocarboxylic acids having one —NRH group, amino—alcohols having one —C(R)₂—OH group and one —NRH group, or mixtures of said difunctional reactants; wherein each R in the (c) and (d) reactants is a hydrogen atom or an alkyl group of 1 to 4 carbons; (B) said styrene compound is of the structure

OR-

wherein R³ is H or an alkyl group of 1 to 10 carbon atoms, optionally substituted with one or two substituents selected from the group consisting of hydroxy, acetoacetoxy, C-_j—C₆ alkoxy, epoxy and halogen, and R¹ is H or methyl.

20. The polymer blend as claimed in Claim 1 wherein,

(e) the remainder being selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,5-pentanediol, 1,4-butane— diol, 1,3—propanediol, 1,3—cyclobutanediol, 2,2-dimethy1-3—hydroxypropy1-2,2-dimethyl-3- hydroxypropionate, butylethylpropanediol and mixtures thereof, except that if ethylene glycol is one of the glycols, at least 30% by weight of one other glycol is used.

21. The polymer blend as claimed in Claim 17 wherein, said polymer blend also contains additives.

22. The polymer blend as claimed in Claim 21 wherein, said additives are selected from the group consisting of surfactants, chain transfer agents, alcohols, anti—foams, coalescing aides, and combinations thereof.

23. The polymer blend of Claim 17 wherein said water- dispersible polyester has an inherent viscosity of from about 0.20 to about 0.38, and acid moiety of from about 80 to about 92 mole percent isophthalic acid and/or terephthalic acid and conversely from about 20 to about 8 mole percent 5—sodiosulfo¬ isophthalic acid, and a glycol moiety of from about 75 to about 100 mole percent diethylene glycol and conversely from about 25 to about 0 mole percent 1,4—cyclohexanedimethanol or 0 — 30 mole % of ethylene glycol or mixtures thereof.

24. The polymer blend of Claim 23 wherein, said acid moiety comprises from about 80 to about 83 mole percent isophthalic acid and conversely from about 20 to about 17 mole percent 5—sodiosulfoisophthalic acid, and said glycol moiety comprises from about 52 to about 56 mole percent diethylene glycol and conversely from about 48 to about 44 mole percent 1,4—cyclohexane—dimethanol.

25. The polymer blend of Claim 1 prepared by polymerizing monomers to form compound (B) in the presence of said polyester or polyesteramide.

26. An aqueous dispersion comprising water and the polymer blend of Claim 1.

27. The aqueous dispersion of Claim 26 wherein, the polymer blend is the polymer blend of Claim 25.

28 The aqueous dispersion of Claim 26 comprising about 20 to about 60 weight percent solids.

29. The aqueous dispersion of Claim 26 comprising about 35 to about 50 weight percent solids.

30. The aqueous dispersion of Claim 27 comprising about 26 to about 60 weight percent solids.

31. The aqueous dispersion go Claim 27 comprising about 35 to about 50 weight percent solids.

32. The aqueous dispersion of Claim 26 containing up to 15 weight percent of a Cl to C4 alcohol.

33. The aqueous dispersion of Claim 26 containing up to 10 weight percent of a Cl to C4 alcohol.

34. The aqueous dispersion of Claim 31 containing up to 15 weight percent of a Cl to C4 alcohol.

35. A method of preparing a water—dispersed polymer blend comprising the steps of:

(A) preparing an aqueous polymerization mixture by contacting (1) a water-dispersible sulfonate group- containing polyester or polyesteramide,

(2) one or more monomers, wherein said monomers comprise: (a) about 50 to about 100 wt. percent of a styrene monomer,

(3) a polymerization initiator, and

(4) water,

(B) polymerizing said monomers to provide said water-dispersible polymer blend.

36. The method of Claim 35 wherein component (2) comprises

(A) about 30 to 100 wt. percent of repeating units from a styrene compound, and

(B) up to 70 wt. percent of repeating units from a (meth)acrylate compound.