CA1253642A - Polymer blends containing ionomeric rubbers and other ionomeric constituents - Google Patents

Abstract

POLYMER BLENDS CONTAINING IONOMERIC RUBBERS
AND OTHER IONOMERIC CONSTITUENTS
ABSTRACT OF THE DISCLOSURE

Polymer blends having improved impact resistance and structural integrity comprise at least one aromatic polymer such as polyphenylene oxide, optionally in combina-tion with a styrene homopolymer; at least one elastomer containing highly polar ionic (e.g., sulfonate or carboxyl-ate) substituents, such as a sulfonated EPDM rubber; and at least one substituted aromatic polymer in which the substit-uents are highly polar ionic substituents, such as a sulfon-ated polyphenylene oxide or styrene-sodium acrylate copoly-mer. The compositions preferably also contain at least one plasticizer.

Description

RD 15~15 POLYMER BLENDS CONT~INING IONOMERIC RUBBERS
AND OTHER IONOMERIC CONSTITUENTS
Introduction and Summary of the Invention This invention relates to aromatic resinous compositions having improved impact properties.
Aromatic polymers such as polycarbonates and polyphenylene oxides (also known as polyphenylene ethers) have ound wide use as engineering resins. Their ; durability and strength has made them suitable for use in areas previously reserved for metals. The necessity for high perofrmance in these areas requires continuing development in the direction of improving properties such as impact resistance and structural integrity.
An example of a resin system in which development is continuing is the polyphenylene oxide system. Polypheny-lene oxides are normally combined ~ith vinyl aromatic poly-~; mers such as polystyrenes for use as engineering resins.
The impact resistance and ease of processing of polypheny-lene oxide-polystyren and similar systems has frequenty been improved by the incorporation therein of a minor pro-portion of elastomeric groups such as those provided by an EPDM rubber, in combination with one or more plasticizers.
It is sometimes found, however, that resionous compositions of this type undergo environmental stress-cracking during . ~
:~,. _ _ _ ~..................................... _,, .

i3~2 and after molding. They may also undergo delamination because of the limited compatibility of the co~stituents.

Polycarbonates are further examples of resin sys-tems which are developing in this area. In general, poly-carbonates derived from bisphenol A have relatively good impact properties. However, there is some tendency toward ; decxeased impact strength with increased thickness of the parts molded therefrom. Also, it would be useful to improve the low-temperature ductility of said parts. On the other hand, polycarbonates derived from such compounds as 2,2',-6,6'-tetramethylbisphenol A are frequently deficient in impact properties and considerable improvement thereof is desired.

A principal object of the present invention, therefore, is to provide a new class of polymer blends.

; A further object is to improve various properties of aromatic polymers, including impact resistance and ten-sile strength, without introducing other problems such as environmental stress-cracking and delamination.

A still further object is to provide novel polvmer blends suitable for use as engineering resins, said blends having a high degree of compatibility and other desirable properties caused by high particle adhesion as a result of a novel mechanism of bonding.

Other objects will in part be obvious and will in part appear hereinafter.
.

~36~ RD- 1581S

In its broadest aspect, the present invention is directed to polymer compositions comprising:

(A) a major proportion of at least one substanti-ally non ionic aromatic polymer;

(B) a minor proportion, effective to increase impact resistance, of at least one elastomer containing highly polar ionic substituents; and (C~ a minor proportion, effective to maintain component B as a substantially stable disperse phase in component A, of at least one substituted aromatic polymer, the substituents thereon being highly polar ionic substitu-ents.

Component A

Component A, the principal polymeric component of the compositions of this invention, is at least one substan-tially non-ionic aromatic polymer. It may be an addition polymer, a condensation polymer, or a mixture thereof. Pre-ferably, it comprises a major amount of condensation poly mers, and it frequently consists entirely of condensation ~ 20 polymers.
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As used herein, the term "substantially aromatic"
denotes a polymer in which a substantial proportion of the mers (i.e., repeating monomer-derived units) contain an aro-matic moiety, such as a ben7ene or naphthalene group. In general, at least about 40% by number of the mers, prefer-ably at least about 90% and frequently 100%, contain an aromatic moiety. The term "substantially non-ionic" denotes RD 15~15 polymers substantially free from highly ionic groups such as sulfonic acid, carboxylic acid, phosphorus acid or quaternary ammonium groups. The polymer may, however, contain moderately polar substituents such as halo, nitro, cyano, amino or the like.
Illustrative addition polymers useful as component A include homopolymers and copolymers of such ethylenically unsaturated aromatic compounds as styrene, chloro-styrenes, bromostyrenes, fluorostyrenes, methylstyrenes, ethylstyrenes, cyanostyrenes, vinylnaphthalene, divinyl-benzene and allylbenzene. Most often, the addition polymer is a styrene homopolymer.
A wide variety of condensation polymers may be used as component A. They include phenol-aldehyde resins, epoxy resins, polyesters, polycarbonates, polyphenylene oxides, polyamides and polyimides~ The preparation and structures of these polymers are well known in the art, and further discussion herein will be limited to the preferred subgenera; i.e., polyphenylene oxides, aromatic polycarbonates, aromatic polyimides, and aromatic polyesters substantially free from ethylenic unsaturation.
For a better understanding of the nature and objects of the present invention, reference will be made to Figures I through VI of the drawings which illustrate chemical formulas referred to throughout the specification.
The polyphenylene oxides are a preferred subgenus of polymers useful as component A, since the present invention has been found extremely useful for preparing polyphenylene oxide compositions with 3~ improved impact resistance and structural integrity.
As is well known in the art, polyphenylene oxides are prepared by the oxidative coupling of phenols, particularly those having the formula in FIGURE I, wherein R is a lower primary alkyl group and R2 is a lower primary or secondary alkyl group, the word `'lower" meaning 3~ Z

that it contains up to 7 carbon atoms. Examples of lower primary alk~l groups are methyl, ethyl, n-propyl, n-butyl, is~butyl, n-am~l, isoamyl, 2-methylbutyl, n-hexyl, 2,3-di-methylbutyl, 2-, 3- and 4-methylpentyl and the corresponding heptyl groups. Examples of lower secondary alkyl groups are isopropyl, sec-butyl and 2-pentyl. Preferably, Rl and R2 are straight chain rather than branched. Since the poly-phenylene oxides in which Xl and R2 are other than methyl generally have no more desirable properties than those in which Rl and R2 are both methyl, and since 2,6-xylenol is the most readily available and cheapest 2,6-dialkylphenol, its use is preferred. The polyphenylene oxide obtained is then poly(2,6-dimethyl-1,4-phenylene oxide).

The polyphenylene oxides useful as component A
include those containing substituents on the aromatic rings, as well as coupled polyphenylene oxides in which the coup-ling agent is reacted with the hydroxy groups of two poly-phenylene oxide chains to increase the molecular weight of the polymer. Illustrative coupling agents are low molecular weight polycarbonates, quinones, heterocycles and formals.
Polyphenylene oxides of these types are known in the art and are disclosed in a large number of patents, including the following:
3,226,361 3,318,959 3,733,307 4,226,951 3,234,183 3,330,806 3,875,256 4,334,050 3,262,892 3,390,125 4,054,533 4,340,696 3,262,911 3,431,238 4,140,675 4,345,050 3,268,478 3,432,466 4,158,728 4,345,051 3,036,874 3,546,174 4,207,406 4,374,959 3,036,875 3,703,564 4,221,881 4,377,662 Aromatic polycarbonates are also useful as compon-ent A. In general, they contain repeating units having the formula in FIGURE II, wherein A1 is an aromatic radical.

~2~36~Z

Illustrative Al radicals include those derived from bis-phenol A, 2,2',6,6'-tetramethylbisphenol A and l,1-di-chloro-2,2-bi~(4-hydroxyphenyl)ethylene. Typical polycar-bonates prepared from these and other aromatic dihydroxy compounds are well known in the art as illustrated by the following patents:
3,153,008 3,334,154 4,073,814 4,217,438 3,157,622 3,635,895 4,130,548 4,239,918 3,169,121 3,737,409 4,195,157 4,379,910 3,269,986 The aromatic polyimides, another class of suitable aromatic polymers, are typically prepared by the reaction of a diamine (such as m-phenylenediamine, 4,4'-diaminodiphenyl-methane or 4,4'-diaminodiphenyl ether) with a dianhydride.
Typical dianhydrides are pyromellitic dianhydride, bis(3,-4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxy-phenyl) sulfide dianhydride and 2,2-bisl4-(3,4-dicarboxy-phenoxy)phenyllpropane dianhydride. Because of the ether groups present in the last-mentioned bisphenol A dianhy-dride, polyimides derived therefrom are normally designated"polyetherimides". Polyimides and polyetherimides are also known in the art as illustrated by the following patents:
3,356,691 3,850,965 3,983,093 4,118,535 3,422,064 3,933,749 4,048,142 4,297,474 3,803,085 3,944,517 4,092,297 4,331,799 3,847,867 3,968,083 ~,107,147 4,332,929 3,847,869 3,975,345 The aromatic polyesters useful as component A are those which are substantially free from ethylenic unsatura-tion. They are illustrated by poly(alkylene dicarboxyl-ates), which normally comprise repeating units of the form-ula in FIGURE III, wherein R3 is a saturated divalent ali-; phatic or alicyclic hydrocarbon radical containing about ~2~ 6~2 ~D-15815

2-10 and usually about 2-6 carbon atoms and A2 is a divalent aromatic radical containing about 6-20 carbon atoms. They are typically prepared by the reaction of at least one alkanediol such as ethylene glycol or 1,4-butanediol with at least one aromatic dicarboxylic acid such as isophthalic or terephthalic acid, or lower alkyl ester thereof. Such poly-esters are known in the art as illustrated by the following patents:
2,465,319 3,047 539 2,720,502 3,671 487 2,727,881 3,953,394 2,822,348 4,128,526 Also useful as component A are copolymers and other interpolymers. These include, for example, polycar-bonates prepared from bisphenol mixtures; polyester-polyçar-bonates; graft polymers; blocX polymers containing polyphen-ylene oxide blocks in combination with polystyrene, polyfor-mal or polycarbonate blocks; and the like. Such copolymers and other interpolymers are disclosed in various patents listed hereinabove.

Mixtures of the above-described poly~ers are also useful. They include mixtures of condensation polymers, of addition polymers, and of condensation with addition poly-mers. Examples are polycarbonate-polyester mixtures and polyphenylene oxide-vinyl aromatic polymer mixtures. The latter are preferred and are illustrated by the following ; patents:
.~

3,383,435 3,787,532 3,639,508 3,943,1gl ~ :
.

~ ~7-, .

;~2~3~4Z RD-15815 The most preferred mixtures of polyphenylene oxide and vinyl aromatic polymers are those which contain about 35~90% and especially about 50-80% polyphenylene oxide, by weight. The vinyl aromatic polymer is usually a styrene polymer and especially a homopolymer; such homopolymers are frequently designated "crystal polystyrene".

The average molecular weights (number average whenever used herein) of the polymers useful as component A
will vary widely, depending in large part on the type of polymer used. In general, molecular weights from about 5,000 to about 500,000 are most suitable. For polyphenylene oxides and polystyrenes, the preferred molecular weight ranges are about 5,000-40,000 and about 50,000-250,000, respectively.

Component B

Component B, the impact resistance-increasing ingredient in the compositions of this invention, is at least one elastomer containing highly polar ionic substitu-ents; i.e., substituents with relatively high charge dens-ity. Said substituent and elastomer are hereinafter some-times referred to as "ionomeric substituent" and "ionomeric elastomer", respectively.

The ionomeric substituents are acidic or strongly basic groups, most often acidic, or salts thereof. Examples are sulfonic or carboxylic acid (both of which are prefer-red), phosphorus acid and quaternary ammonium base groups and their salts which are stable at the processing tempera-tures of the compositions of this invention. Mixtures of any of the foregoing substituents are also suitable.

~ 6~ RD- 15815 Methods for their introduction into the elastomers, herein designated "ionomerization", are described hereinafter.

In general, it is preferred for at least part (typically at least about 35% and frequently all) of the ionomeric groups to be in the salt form. Examples of suit.-able acid salts are metal, ammonium, alkylammonium, phos-phonium and alkylphosphonium. The metal salts, which are preferred, are illustrated by alkali metal, alkaline earth metal and zinc; sodium and zinc are especially preferred.
Typical base salts are the chlorides, bromides, sulfates, sulfonates and phosphonates; the latter two may be either aliphatic or aromatic.

A characteristic property of the ionomeric elasto-mers is their "degree of ionomerization", which is defined as the mole percent of ionomeric groups based on mers in the polymer; in other words, as the number of ionomeric mers per 100 mers. The degree of ionomerization o component B which is preferred for the purposes of this invention is within the range of about 0.1-10%, especially about 0.25-5%.
,, .
The base elastomer for component B may be any elastomer known in the art. Examples thereof are provided in Encyclopedia of P_lymer _ience and Technology, Vol. 5, pp. ~06-482 (1966) A preferred subgenus of elastomers consists of 25- those having a carbon atom backbone; that is, those in which the polymer chain consists entirely of carbon atoms. These are usually substantially free, and preferably entirely free, from aromatic moieties. The include natural rubber, 36~2 synthetic diene rubbers such as polybutadiene and polyiso-prene, butyl rubbers, polyisobutene rubbers, ethylene-pro-pylene rubbers, ethylene-propylene-diene rubbers wherein the diene is non-conjugated (EPDM rubbers), chloroprene rubbers, and others known in the art. The molecular weights of said rubbers, before ionomerization, are typically about 10,000-250,000 and most often about 20,000-100,000.

The ionomerization of the above-described elasto-; ~ mers may be effected by known methods. For example, carbox-ylated rubbers are typically obtained by polymerization of a monomer mixture which includes an acid such as acrylic or ; methacrylic acid, or an ester thereof (e.g., ethyl acrylate, methyl methacrylate) in which the ester groups are subse-quently hydrolyzed to free acid groups. A similar technique may be used for the preparation of sulfonated rubbers, using such monomers as 2-sulfoethyl methacrylate, sodium styrene-; sulfonate and 2-acrylamido-2-methylpropanesulfonic acid.
Sulfonated carbon-backbone rubbers may also be prepared as disclosed in ~nited States Patent Number 3,642,728 ~;
which Patent-issued on Fe~ruary 15, 1972. White phosphorus reacts with olefins in the presence of oxygen to yield phos-phonic acids, and elastomeric phosphonate ionomers may be obtained by subjecting diene rubbers containing olefinic ; linkages to this reaction. Quaternary ammonium-ionomerized rubbers may be prepared by reacting a chlorinated derivative of a rubber, or a chloroprene rubber, with ammonia or an amine followed by quaternization.

Any of the foregoing acidic or basic substituents may be converted to their salts by known methods, typically by reaction with a base or acid, respectively.
;

~ O-' A second subgenus of ionomeric elastomers consists of those having hetero backbones; i.e., containing more than one element in the polymer chain.
These elements may include, for example, carbon, oxygen, nitrogen and silicon.
Illustrative polymers with hetero backbones include polyurethanes, polyethers and polysiloxanes, with the polysiloxanes being preferred. Typical ionomeri polysiloxane elastomers are represented by the formula in FIGURE IV, wherein each R is independently a lower alkyl radical and preferably methyl, X is an organic substituent containing an ionomeric moiety, and m and n are integers, with m being from about lOn to about lOOOn and preferably from about 30n to about 400n.
For the purpose of determining degree of ionomerization, each parenthesized structure in the formula in FIGURE IV
is considered a mer. The molecular weights of such polysiloxanes are generally about 10,000-50,000.
The X value in the above formula is an organic radical which may contain ionomeric substituents such as any of those previously described. In a preferred embodiment, X is a switterionic radical, usually a sulfoalkyl-substituted mono- or diaminalkyl radical.
The aminoalkyl radical is ordinarily lower aminoalkyl, and the sulfoalkyl substituents thereon normally contain \ about 2-4 carbon atoms.

- 11 ~

~f~53~

The preparation of typical zwitterionic polysiloxane elastomers is described by Graiver et al, in Journal of Polymer Science: Polymer Chemistry Edition, -17, 3559-3572 (1979), and may be effected by preparing a dimethylsiloxane-4,7-diazaheptylmethylsiloxane copolymer and reacting it with 1,3-propanesultone. In the resulting polysiloxane, X may have the formula in FIGURE V, or, somewhat less preferably, one amino group may be unsubstituted.
The ionomeric polysiloxane elastomers, including the above-described switterionic elastomers, are normally derived from base polysiloxanes having molecular weights of about 5000-150,000 and preferably about 10lO00-100,000. The preparation of such switterionic elastomers is illustrated by the following example.

A mixture of 700 grams (9,~4 moles) of octamethylcyclotetrasiloxane, 29.2 grams (0.142 mole) of 4,7-diazoheptylmeth~ldimethoxysiloxane, 4.19 grams (0.0135 mole) of potassium hydroxide was heated at 125-180C
with stirring for 20 hours. It was then cooled to 100C, 2.5 grams of sodium bicarbonate was added and heating at that temperature was continued for 1 hour.
The mixture was cooled, diluted with 1200 ml. of toluene and filtered using a filter aid material.
The filtrate was washed twice with 300 ml. of distilled water, concentrated to about 800 ml. and diluted ~ \
\

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~ 3~

with toluene to 1.5 liters. 1,3-Propanesultone, 31.72 grams (0.492 mole), was added and the mixture was stirred at room ; temperature overnight, after which water and volatiles were removed by vacuum evaporation. The product was the desired zwitterionic polysiloxane elastomer having a number average molecular weight of about 30,000 and a degree of ionomeriza-tion of about 0.72%. It may be represented by the formula in FIGURE VI, wherein m is about 266n.

Illustrative ionomeric polyurethane and polyether elastomers may be prepared by the incorporation of N-methyl-diethanolamine units in the polymer and quaternization of said units with 1,3-propanesultone, as described by Hwang et al. in ~y~ __e n~ and Science, 21, 1027-1035 (1981), and by Yang et al. in Makromol. Chem., 184, 651-668 (1983). Also useful are the ionomers prepared by reacting 1,4-butanesultone with free secondary amine groups in poly-urethanes derived from polyalkylene polyamines, as described in German Patent 922,736.

` The polysiloxane, polyurethane and polyether elas-tomers may also contain other ionomeric groups. For exam-ple, quaternary ammonium base-ionomerized polysiloxanes may be prepared by quaternizing the previously described amino-alkyl-substituted polysiloxanes.

The glass transition temperature (Tg) of the iono-meric elastomer should be quite low. It is generally nohigher than -20C and preferably below about -40C.

It has previously been observed that elastomers having favorable tensile properties were effective for ~ 2 RD-15815 impact modification of various polymers. It has now been discovered, however, that the ionomeric polysiloxanes are useful as component B even though their tensile properties are not particularly favorable. In general, it appears that the impact properties of the compositions o this invention do ~ot parallel the tensile properties of the ionomeric ; elastomer.

Component C
. ., In mo~t cases, it has been found that mixtures of a major proportion o~ component A with a minor proportion of component B are subject to phase separation or delamination, sometimes referred to as "incompatibility". This problem is solved according to the present invention by incorporating a minor proportion of component C which is at least one sub-i 15 stituted aromatic polymer, the substituents thereon being highly polar ionic substituents. Component C is typically prepared from an aromatic polymer of the type described hereinabove with reference to component A. Preferably, com-ponent C is an ionomeric derivative of component A, or, when component A is a mixture, of at least one constituent of said mixture. However, it is also within the scope of the invention to use as component C an ionomeric derivative of a polymer which is different from component A, provided said ionomeric derivative is effective in the manner described herein.

The highly polar ionic substituents on component C
are, in general, the same ones described with reference to -~ component B. Thus, they are typically sulfonic acid, car-boxylic acid, phosphorus (e.g., phosphonic) acid or quater-; 30 nary ammonium hydroxide groups and salts thereof; the salts ., ~ -14-3~64:;2 RD 15~15 are preferred. It is especially preferred that the substituents on components B and C be the same, and most preferably that they all be sulfonate or carboxylate substituents. However, it is also contemplated, for example, for component B to contain carboxylate substituents and component C su]fonate substituents or vice versa. It is also contemplated for one components to have anionic and the other cationic substituents, whereupon they neutralize each other and no further salt formation is necessary.
Ionomerization of the aromatic polymer to produce component C may be accomplished by methods known in the art. For example, the carboxylic and sulfonic acids or esters disclosed hereinabove with ; 15 reference to component B may be incorporated in a monomer mixture containing styrene or the like to form an ionomeric addition polymer. Sulfonate groups may also be incorporated in aromatic polymers by reaction with sulfonating agents such as sulfur trioxide or acetyl sulfate or sulfur trioxide, preferably complexed with a deactivating agent such as triethyl phosphate as disclosed and claimed in commonly assigned United States Patent Number 4,574,144, issued March 4, 1986, Illustrative sulfonation methods are disclosed in 25 U.S. Patent No. 3,870,841, issued ~arch 11, 1975 to Makowski et al. Quaternary ammonium groups may be introduced by nitration followed by reduction and quaternization and phosphonic acid groups by nitration, reduction, formation of a diazonium salt (e.g., the fluoroborate), reaction of said salt with phosphorus trichloride and hydrolysis.
The preferred molecular weight ranges for the aro-matic polymers which were ionomerized to produce component C
are generally the same as those for component A. The degree : ~, : ~'' ' ,.
.~. .
, ' ' " -~' ' :,- ' ';
. .~,. .
;~ .

~;3~i~2 RLi-15815 of ionomerization of component C is typically about 0.5-10%
and most ~ften about 1-5%. For ionomerized polyphenylene oxides, a degree of ionomerizati~n of about 1-3% is fre-quently preferred since impact strengths are often maximized at that level.

While the present invention is not dependent on theory, it is believed that the improved properties afforded thereby are a result of polar interactions between the iono-meric groups in components B and C. These interactions, coupled with the compatibility of components A and C as result of their structural similarity by reason of the aro-matic content thereof, constitute a novel mechanism of bond-ing which permits the incorporation of component B, the impact modifier, as a substantially stable disperse phase in component A. Such incorporation in ~urn minimizes delamina-tion and similar types of physical ailure.

The preparation of ionomeric polymers useful as component C in the compositions of this invention is illus-trated by the following examples.

A solution of 76 ml. of acetic anhydride in 400 ` ml. of 1,2-dichloroethane was cooled to 10C and 48.9 grams of 95% sulfuric acid was added dropwise over 20 minutes. A
300-ml. portion of the resulting sulfonating agent was added dropwise at 50C, over 10 minutes, to a stirred solution in three liters of l,2-dichloroethane of 625 grams of a poly-(2,6-dimethyl-1,4-phenylene oxide) having a molecular weight of about 20,000 and an intrinsic viscosity in chloroform at 25C of 0.48 dl./g. The mixture was stirred for 60 minutes, ~53~2 RD-15815 after which 200 ml. of methanol and a solution of 65 grams of zinc acetate in 200 ml. of water were added. The mixture was poured into an excess of methanol and the precipitated ionomer was removed by filtration and dried in a vacuum oven. There was obtained about 600 grams of the desired zinc salt of the sulfonated polyphenylene oxide; it con~
tained 1.4% sulfur and had a degree of ionomerization of about 5.3%

The procedure of Example 2 was repeated, except that the 1,2-dichloroethane and polyphenylene oxide were respectively replaced, on an equal weight basis, by methyl-ene chloride and a styrene homopolymer having a molecular weight of about 106,000 and an intrinsic viscosity in tolu-ene at 25C of 0.80 dl./g., and the sulfonation was effected at reflux temperature. There was obtained about 600 grams of the desired zinc salt of the sulfonated polystyrene; it contained 1.3% sulfur and had a degree of ionomerization of about 4.2%.

Component D

In a preferred embodiment of the invention, the compositions additionally comprise (D) at least one plasti-cizer, which facilitates molding and other working opera-tions by lowering the melt viscosity of the composition.
':
A wide variety of plasticizers are suitable for use as component D. In general, they are polar materials ~; melting at least 53C below the processing temperature of the resinous components of the composition; for systems :.

3~2 containing a substantial amount of polyphenylene oxide, the plasticizers should melt no higher than about 190C. It is also preferred that their volatility ~e sufficie~tly low to permit their retention in the composition during processing.

Typical plasticizers include compounds containing at least one of oxygen, phosphorus and nitrogen atoms, and compounds releasing a small polar molecule such as water or methanol at elevated temperatures. In addition to serving as plasticizers, compounds containing phosphorus may act as flame retardant additives.

Examples of oxygen-containing materials are ^~ organic acids and their salts and esters such as stearic acld, lauric acid, calcium stearate, zinc laurate, zinc stearate, magnesium laurate, aluminum ricinoleate, dimethyl sebacate and dimethyl phthalate; and alcohols, phenols and ethers such as hexyl, alcohol, nonylphenol, resorcinol, ben-zyl alcohol and ethyl hexyl ether.

Illustrative phosphorus-containing compounds are triphenyl phosphate, tri-p-tolyl phosphate, tris(3,5-dimeth-ylphenyl) phosphate, tributyl phosphate, triisopropyl phos-phate and tetraalkylphosphonium p-toluenesulfonate. Nitro-; gen-containing materials include stearamide, p-toluenesul-fonamide, diphenylurea, diphenylguanidine, di-o-tolylguani-di~e, piperazine, aniline, dihexylamine, diphenylamine, phenyl-~-naphthylamine and tetraalXylammonium p-toluenesul-fonate.

Polar molecule-releasing materials include various hydrates of simple and mixed oxides and salts such as lith-ium sulfate dihydrate, ammonium cerium sulfate octahydrate, ~53~ R~-15815 ammonium chromium (III) sulfate dodecahydrate, ferric ammon-ium sulfate dodecahydrate, barium oxide octahydrate, bismuth dioxide dihydrate and the like, and alcoholates such as cal-cium chloride tetramethanolate.

The preferred pLasticizers, especially when com-ponent A is entirely or partially polyphenylene oxide, are triaryl phosphates and the metal (especially zinc) salts of fatty acids. In most instances a combination of the two is used, typically containing about 40-70% by weight triaryl phosphate with the balance being metal salt.

Component Pro~o tlons The amount of component B in the compositions of this invention may be any amount effective to provide the desired degree of impact resistance. The amount of compon-; 15 ent C is an amount effective to maintain component B as a substantially stable disperse phase in component A. While it is within the scope of the invention for component B to be soluble in the resin system, solubility is not necessary and is frequently unattainable.

In general, the compositions of the invention com-prise about 50-85% by weight of component A, about 2-20% of component B and about 2-40% of component C, based on total weight of the resinous componeIlts (i.e., of the combination of components A, B and C). It is generally found that com-positions in which component B is a polysiloxane ionomer : require less of component B and often more of component C
than those in which component B has a carbon backbone. Most often, the compositions in which component B has a carbon backbone may advantageously contain about 70-85% of ;:

~ --19---`'`' 36a~;~

component A, about 5-15% of component B and about 2-20% of component C. On the other hand, when component B is ; polysiloxane-based the preferred proportions are about 50-80% of component A, about 3-10% of component B and about 15-40% of component C.

Component D, when present, is generally in the amount of about 5-35 phr. (parts by weight per 100 parts of resinous components). In general, less plasticizer is required when component A consists entirely of condensation polymer than when it is a blend of condensation and addition polymers. In the former case the preferred plasticizer range is about 5-15 phr., and in the latter case about 20-35 phr.

While the presence of a plasticizer in the compos-; 15 itions of this invention may be desirable for the aforemen-tioned purposes, the level thereof should generally be no ; higher than necessary since tensile strength tends to decrease with increasing plasticizer level. One advantage of using a zinc salt as component C, rather than a salt con-tainin~ another cation such as sodium, is that it frequently : enables one to use a lower level of plasticizer, thus increasing tensile strength.

Details_of P~paration; Spe i_ic Embodiments The compositions of this invention are normally prepared by merely blending the ingredients thereof under conditions adapted for the formation of an intimate blend.
Such conditions often include extrusion, typically at tem-peratures in the range of about 100-300C. Extrusion is typically effected in a screw-type or similar extruder which ~ -20-:
:~

~3~ RD-15815 applies a substantial shearing force to the composition, thereby decr~asing the particle size thereof.

One of the advantageous features of the present invention is a result of the effectiveness of component C to promote uniform particle size of component B and adhesion of the particles thereof to the continuous or external phase which comprises chiefly component A. An examination of the fracture surfaces of Izod impact bars with a scanning elec-tron microscope shows that the elastomer particles therein are quite uniform in particle size, a major proportion of the particles thereof being in the 0.1-3.5 micron and most often in the 0.2-1.5 micron range. These particles are uni-formly dispersed in the polymer matrix and adhere well thereto, minimi7ing delamination. By contrast, blends from which component C is absent contain less uniform, poorly adhered elastomer particles.

In addition to the ingredients described in detail herein, the compositions of this invention can also contain other materials such as fillers, pigments, ultraviolet sta-bilizers, anti-static agents and mold release agents.
; ~ Materials useful for these purposes, and the proportions useful in the compositions of this invention, will be appar-ent to those skilled in the art.

The preparation of the compositions of this inven-tion is illustrated by the following examples. All parts ; ~ and percentages except degree of ionomerization are by weight.

, ., 53~Z

In component A, the polyphenylene oxide was a poly-(2,6-dimethyl-1,4-phenylene oxide) having a molecular weight of about 20,000 and an intrinsic viscosity in chloro-form at 25C of 0.48 dl./g. The polystyrene was "Monsanto Lustrex HH 101", a commercially available styrene homopoly-mer havin~ a molecular weight of about 106,000 and an intrinsic viscosity in toluene at 25C of 0.80 dl./g.

Component B was "Uniroyal IE-2590", a commercially available zinc sulfonate derived from a sulfonated EPDM
rubber having a molecular weight of about 50,000 and con-taining an average of 13 sulfonate groups per molecule, for a degree of ionomerization of about 0.86%. It has a Tg of about -60C. The sulfonated polyphenylene oxide comprising component C was prepared according to the method of Example 2, varying the amount of sulfonating agent to afford the appropriate degree of ionomerization and neutralizing with ; zinc acetate.
:
The compositions were prepared by blending the appropriate proportions of ingredients, mixing in a jar mill for 2 hours and extruding on a twin screw extruder at about 160-270~C. The extruded material was ~uenched in water, pelletized and dried at 80C. Test specimens were then pre-pared by injection molding and tested for Izod impact (ASTM
procedure D256), compared with a control in which component C was absent. The fracture surfaces of the specimens after the Izod test were visually inspected for delamination; no substantial delamination was observed for Examples 4-6.

~`
`~ ~

z The compositional and test data for Examples 4-6 are listed in Table I.
TABLE I
Example 5 In~redient 4 5 6 Control Component A, % of total resins 75.3 75.370.1 91.7 Polyphenylene oxide:
% of total resins S2.0 52.0 51.955.0 ~ % of component A 68.9 68.9 74.160.0 ; lO Polystyrene, % of total resins 23.3 23.318.2 36.7 Component B, % of total resins 11.7 11.711.7 8.3 Component C
% of total resins 13.0 13.0 18.2 ----Degree of ionomerization, % 0.8 1.3 4.2 ----15 Component D, phr. 29.9 29.9 29.9 21.1 Triphenyl phosphate18.2 18.2 18.2 12.8 Zinc stearate 11.7 11.7 11.7 8.3 Impact strength, ft.-lb./in. 1.45 lO.0 2.0 0.2 It is apparent from Table I that the compositions of this invention are superior in impact strength to compos-itions containing only components A and B. The superior impact strength of compositions in which component C has a degree o~ ionomerization within the 1-3% preferred range is also evident from a comparison of Example 5 with Examples 4 and 6.

The constituents of component A were the same as in Examples 4-6. Component ~ was "Uniroyal IE-1025", a com-mercially available zinc sulfonate similar to "Uniroyal 30 IE~2590" except that it contains an average of 5 sulfonate ,' ~ -23 ...

~i;3~LZ

groups per molecule and has a degree of ionomerization of about 0.33%. The sulfonated polystyrene comprising compon-ent C was prepared according to the method of Example 3, varying the amount of sulfonating agent to afford the appro-priate degree of ionomerization and neutralizing with zincacetat~ or sodium hydroxide as appropriate.

The compositions were prepared as in Examples 4-6 and tested (in comparison with a control in which component C was absent) for Izod impact strength and, in some in-stances, for tensile strength (ASTM procedure D638, Type Vspecimen). No substantial delamination was observed for : Examples 7-15.

~ The compositional and test data for Examples 7-15 ,. _ ._ .,___ _ : ~

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rl r~oa o ,t~ -- I I 1 0-- I

3 ~ _0 0 (~J 3 ~O 0 0 0 ~1 0 o ~ 0 o o I ~ o o~ o _ 0 t`J O 0~ N ~ ~U ~`J 1` `O--3 :rl I 0 1 _ 1 3 0~0_ ~-Cl ~ 0 1-- t~ N 1--0 _1 030~ 0 ~ 3 C~ 0--~--o ~ ~ ~1-- 0 ~ N 0~ I~J 1~ o --I 0 3 0 ~ -- t~ 0--~
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C C ~ ~_ ~ C C V) ~ C~ C C) ~' ._ O O ~, ~) C O ._ L C C~ O ~
C E CL C ' ~I - C C~ C

~2~ RD-15815 The results in Table II, like those in Table I, show the favorable impact strengths generally possessed by the compositions of this invention when compared to composi-tions not containing component C. They also indicate some trends resulting from changes in various parameters. Exam-ples 9, 12 and 13, for instance, demonstrate the results of varying the level of component B in the compositions, and especially of decreasing said level below about 5%. Exam-ples 7 and 9 show the superiority of zinc salts to sodium salts as component C with respect to impact strength, and Examples 9-11 show the relatively small e~fect of the level of zinc salt on impact strenqth. A comparison of Examples 8 and 14 on the one hand and Examples 9 and 15 on the other shows the superiority of zinc salts to sodium salts as com-ponent C with respect to plasticizer level and the effectthereof on impact strength. Finally, the effect of lower plasticizer levels, where possible, on tensile strength is apparent from a comparison of Examples 9 and 15.

These examples are similar to Examples 4-6 except that component B was the ionomeric polysiloxane elastomer of Example l. The method of making the compositions was the same as that used in Examples 4-6 except that the blend was homoqenized in a Henschel mixer prior to extruding. The compositional and test data are given in Table III (in com-parison with two controls as indicated). As with Examples

4-6, the compositions of Examples 16-18 showed substantially no delamination.

~2~36~2 RD-15815 TABLE III
ExampleControls ~E~ _ n 1617 18 A B
Component A, % of total resins 79.0 64.9 58.4 83.3 67.5 Polyphenylene oxide:
% of total resins 79.051.9 45.4 83.3 54.5 % of Component A 10080.0 66.4 100 80.7 Polystyrene, % of total resins -- 13.0 13.0 --- 13.0 Component B, % of total resins 4.3 9.1 9.1 -~
Component C
% of total resins 16.726.0 32.5 16.7 32.5 Degree of ionomerization, %1.3 2.8 1. 3 1.3 3.7 Component D, phr. 8.229.9 29.9 11.1 29.9 Triphenyl phosphate 4.118.2 18. 2 4.4 18.2 Zinc stearate 4.111. 7 11.7 6.7 11.7 Impact strength, ft.-lb./in. 1.8 8.5 2.6 1.0 0.8 .
In addition to the demonstration in Table III of the utility of compositions in which component B is a poly-siloxane elastomer, Examples 17 and 18 illustrate the favor-- 20 able effect on impact strengtll of the use of a combination of polyphenylene oxide and polystyrene as component A, especially when said combination contains at least about 50%
polyphenylene oxide.

EXAMPLES_19-22 .
In component A, the polyphenyleIIe oxide and poly-styrene were those of Examples 4-6. Component B was pre-pared by preparin~ a methylene chloride solution of "Polysar Krynac 221", a commercially available elastomeric terpolymer r~
of 66.7 mole percent butadiene, 28.8 mole percent acryloni-trile and 4.5 mole percent acrylic acid having a degree of ionomerization of 4.5%; reacting the solution with 40 mole .,.

.... . . ;

~2536~2 R~~15815 percent of a solution of sodium hydroxide in aqueous isopropanol; and vacuum stripping the sol~ents. The resins used as component C were the zinc salt of a sulfonated polystyrenc similar to that of Example 3 and a styrene-sodium acrylate copolymer containing 7.1 mole percent sodium acrylate units (and thus having a degree of ionomerization of 7.1%) and prepared by neutralization of a commercially available styrene-acrylic acid copolymer.

The compositions were prepared by blending the appropriate proportions of ingredients, mixing in a jar mill for one hour and extruding on a twin screw extruder at about 160-280C. The extruded material was quenched in water, pelletized and dried at 80C. Test specimens were then pre-pared as in Examples 4-6 and tested (in comparison with con-trols) for Izod impact strength. The compositional and testdata are given in Table IV. The compositions of Examples : 19-22 showed no delamination, while severe delamination was observed in the controls.
.

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.

~536~2 RD-15815 In general, Table IV show3 the same trends as Tables I III. The apparent similarity in properties of the composition of Example 21 to Control B is reflected only in impact strength since, as previously noted, the latter was substantially inferior to the former with respect to dalam-ination.

, .

Following the procedure of Examples 4-6, a polymer blend was prepared comprising the following:

Component A: 51.8 parts of a 2,2'-6,6'-tetrameth-ylbisphenol A polycarbonate having a molecular weight of 15,500 and an intrinsic viscosity in chloroform at 25C of 0.53 dl./g., and 27.0 parts of "Monsanto Lustrex HH-101".

Component B: 10.6 parts of the zinc salt of a sul-fonated EPDM rubber having a degree of ionomerization ofabout 0.15% and prepared from "Vistalon 3708", a commerci-ally available EPDM rubber available from Exxon Corporation which has a molecular weight of about 50,000.

Component C: 10.6 parts of the sulfonated styrene homopolymer of Example 3.

Component D: 7.1 phr. of triphenyl phosphate; 10.6 phr. of zinc stearate.

. . _ . .

; Following the procedure of Examples 4-6, a polymer blend is prepared comprising the following:

~:, ~3Çi~2 Component A: 82 parts of a polyetherimide having a molecular wei~ht of about 20,000 and an intrinsic viscosity in chloroform at 25C of 0.47 dl/g., prepared by the reaction of approximately equimolar quantities of 2,2-bis[4-(3,-4~dicarboxyphenoxy)phenyl]propane dianydride and m-phenylene diamine.
Component B: 9 parts of the ionomeric elastomer of Example 19.
Component C: 9 parts of the zinc salt of a sulfonated polyetherimide prepared by the reaction of a polyetherimide of component A wlth a sulfur tiroxide-diethyl phosphate complex at about 25C.
Examples 25-26 In component A, the polyphenylen oxide and polystyrene were those of Examples 4-6, and component B
was "IJniroyal IE-2590". The resins used as component C
;~ were the styrene-sodium acrylate polymer of Exampls 19-22 and its acidic (i.e., non-neutralized) counterpart.
The compositions were prepared as in Examples 19-22 and test specimens were evaluated for delamination, im comparison with controls. The compositional and test data are given in TABLE V.
; TABLE V
Ingredient Example 26 Control Component A, % of total resins76.6 76.6 88.3 Polyphenylene oxide:
% of total resins 64.9 64.9 64.9 % of Component A 84.7 84.7 73.5 Polystyrene, % of total resins 11.7 11.7 23.4 Component B, % of total resins11.7 11.7 11.7 Component C, % of total resins Styrene-sodium acrylate copolymer 11.7 Styrene-acrylic acid copolymer ---- 11.7 ----Component D, phr. 29.9 29.9 Triphenyl phosphate 18.2 18.2 Zinc stearate 11.7 11.7 Delamination None None Some ; - 31 -

Claims (33)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A polymer composition comprising:
(A) from 50% to 85% by weight of the total polymer composition of at least one condensation polymer selected from the group consisting of polyphenylene oxides, aromatic polycarbonates, aromatic polyimides and aromatic polyesters substantially free from ethylenic unsaturation, or a mixture thereof with at least one addition polymer;
the remainder of said composition comprising:
(B) at least one elastomer having highly polar ionic substituents selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof; and (C) at least one aromatic polymer having highly ionic substituents thereon.

2. A composition according to claim 1 wherein the condensation polymer portion of component A is at least one polyphenylene oxide having a number average molecular weight of about 5,000-40,000.

3. A composition according to claim 2 wherein the substituents on component B are sulfonate or carboxylate substituents and wherein its degree of ionomerization is from about 0.1% to about 10%.

4. A composition according to claim 3 wherein component A is a mixture of said polyphenylene oxide with a styrene homopolymer having a number average molecular weight of about 50,000-250,000, said mixture containing about 35-90% by weight polyphenylene oxide.

5. A composition according to claim 4 wherein said polyphenylene oxide is a poly(2,6-dimethyl-1,4-phenylene oxide).

6. A composition according to claim 5 wherein component B has a molecular weight of about 10,000-250,000 and a glass transition temperature no higher than about -20° C.

7. A composition according to claim 6 wherein component B is a sulfonated EPDM rubber and the substituents thereon are selected from the group consisting of zinc sulfonate and carboxylate substituents.

8. A composition according to claim 3, 4 or 7 wherein component B is a copolymer of butadiene, acrylonitrile and acrylic acid which has been at least partially neutralized with sodium hydroxide.

9. A composition according to claim 1 wherein component C is an ionomeric derivative of at least one constituent of component A.

10.A composition according to claim 1, 3 or 7 wherein component C has a degree of ionomerization of about 0.5-10% and the substituents thereon are selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof.

11. A polymer composition comprising:
(A) from 50% to 85% by weight of the total polymer composition of at least one condensation polymer selected from the group consisting of polyphenylene oxides, aromatic polycarbonates, aromatic polyimides and aromatic polyesters substantially free from ethylenic unsaturation, or a mixture thereof with at least one addition polymer;
(B) from 2% to 20% by weight of said total composition of at least one elastomer having highly polar ionic substituents selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof; and (C) from 2% to 40% by weight of said total composition of at least one aromatic polymer having highly ionic substituents thereon.

12. A composition according to claim 11 wherein component C has a degree of ionomerization of about 0.5-10% and the substituents thereon are selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof.

13. A composition according to claim 12 wherein component A is at least one polyphenylene oxide having a number average molecular weight of about 5,000-40,000.

14. A composition according to claim 13 wherein component B is a sulfonated EPDM rubber and the substituents thereon are selected from the group consisting of zinc sulfonate and carboxylate substituents.

15. A composition according to claim 12, 13 or 14 wherein the substituents on component C are zinc or sodium sulfonate substituents.

16. A composition according to claim 12, 13 or 14 wherein component C is a sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) having a degree of ionomerization of about 1-3%.

17. A composition according to claim 12, 13 or 14 wherein component A comprises from 70% to 85% by weight, component B comprises from 5% to 15% by weight and component C comprises from 2% to 20% by weight based on the weight of the total polymer composition.

18. A polymer composition comprising:
(A) from 50% to 85% by weight of the total polymer composition of at least one condensation polymer selected from the group consisting of polyphenylene oxides, aromatic polycarbonates, aromatic polyimides and aromatic polyesters substantially free from ethylenic unsaturation, or a mixture thereof with at least one addition polymer;
(B) from 2% to 20% by weight of said total composition of at least one elastomer having highly polar ionic substituents selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof;
(C) from 2% to 40% by weight of said total composition of at least one aromatic polymer having highly ionic substituents thereon; and (D) at least one plasticizer, said plasticizer being a polar material melting at least 50° below the processing temperature of the resinous components of the composition.

19. A composition according to claim 18 wherein the condensation polymer portion of component A is at least one polyphenylene oxide having a number average molecular weight of about 5,000 to 40,000.

20. A composition according to claim 19 wherein the substituents on component B are sulfonate or carboxylate substituents and wherein its degree of ionomerization is from about 0.1% to about 10%.

21. A composition according to claim 20 wherein component A is a mixture of said polyphenylene oxide with a styrene homopolymer having a number average molecular weight of about 50,000-250,000, said mixture containing about 35% to 90% by weight polyphenylene oxide.

22. A composition according to claim 21 wherein said polyphenylene oxide is a poly(2,6-dimethyl-1,4-phenylene oxide).

23. A composition according to claim 22 wherein component B has a molecular weight to about 10,000-250,000 and a glass transition temperature no higher than about -20°C.

24. A composition according to claim 23 where component B is a sulfonated EPDM rubber and the substituents thereon are selected from the group consisting of zinc sulfonate and carboxylate substituents.

25. A composition according to claim 21, 23 or 24 wherein component C is an ionomeric derivative of at least one constituent of component A.

26. A composition according to claim 21, 23 or 24 wherein component C has a degree of ionomerization of about 0.5% to 10% and the substituents thereon are selected from the group consisting of sulfonic acid, carboxylic acid, phosphorus acid and quaternary ammonium base substituents and salts thereof.

27. A composition according to claim 20 wherein said plasticizer contains at least one of oxygen, phosphorus and nitrogen atoms or releases a small polar molecule at elevated temperatures.

28. A composition according to claim 21, 23 or 24 wherein component D is present in an amount of from 5 to 35 parts by weight per 100 parts of polymer composition.

29. A composition according to claim 21, 23 or 24 wherein component D is present in an amount of from 5 to 35 parts by weight per 100 parts of resinous components and component D is a combination of about 40% to 70% by weight of triaryl phosphate with the balance being zinc salts of said fatty acids.

30. A polymer composition comprising:
(A) from 70% to 85% by weight of the total polymer composition of a blend of poly(2,6-dimethyl-1,4-phenylene) oxide and a styrene homopolymer, said blend comprising about 50% to 80%
poly(2,6-dimethyl-1,4-phenylene) oxide;
(B) from 5% to 15% by weight of said total composition of an elastomer having a degree of ionomerization of 0.25% to 5% and selected from the group consisting of zinc salts of sulfonated EPDM
rubbers and partially neutralized butadiene-acrylonitrile-acrylic acid terpolymers;
(C) from 2% to 20% of a compatibilizer having a degree of ionomerization of 1% to 5% and selected from the group consisting of zinc salts of sulfonated polystyrenes and styrene-sodium acrylate copolymers; and (D) from 20 to 35 parts by weight per 100 parts of resinous components, of a triphenyl phosphate-zinc stearate plasticizer mixture comprising about 40 to 70% triphenyl phosphate.

31. A composition according to claim 30 wherein component C has a degree of ionomerization of about 1% to 3%.

32. A composition according to claim 30 or 31 wherein component C is a zinc or a sodium salt of a sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) having a degree of ionomerization of about 1% to 3%.

33. A composition according to claim 30, 31 or 32 wherein said styrene homopolymer in component A
has a number average molecular weight of 50,000 to 250,000.