CA1040774A - Polyblends of nitrile rubber and preplasticized vinyl resins - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Polyblends of nitrile rubbers and vinyl polymers, wherein the vinyl polymers have been prepared by polymerizing the vinyl monomer or monomers in the presence of a plasticizer therefor, and wherein said rubbers and polymers are blended together with or without an emulsion of additional plasticizer for the resultant polyblends, and the process of making said polyblends. The polyblends have a variety of uses such as in packaging, in cable jacketing, and so forth. They are particularly useful where flexibility is needed, such as in films, coatings, such as in coating fabrics, non-wovens, and like substrates. Further, when non-flammable properties are desired in the end product, it is a simple matter to choose a suitable plasticizer which will result in such properties.
More importantly, the polyblends of the present invention are very readily and easily transformed to finely divided powder form by standard procedures which results, not only in ease of handling and shipping, but provides economic advantages in processing the same to the ultimate user or fabricator.

Description

BACKGROUND OF THE INVFNTION
It 18 well knotJn thst vinyl resins may be plasti-cized or changed from the hard, horny and stlff state to a ~; soft, plastlc, workable condition by the add~tion at elevsted temperatures of certain plastlc~zers, such a~ dloctyl phtha-i late, and the like. Also, lt is well known that vinyl resin~
may be converted into a re~ilient, resistant rubber-like cQm-positlon by blending lt on a conventional mlxlng machlne of the type normally used for mixing rubber or plastics, for example, ~0 a roll mill or a Banbury mixer, with h synthetic rubber co-polymer of butadiene -1,3 and acrylonltrile. Blends of thls type are referred to a~ "polyblends" and normally have a plastlclzer for the vinyl resin incorpor~ted therein. In ad-dltion, the~e blends must be n uxed, or heated to a pr~determined temperature durlng m~xlng in order to sufficlently soften the vlnyl resln. ml8 18 tlme consumin~ and expenslve An alternate approach to ~klng the polyblends 18 to blend a rubber copolymer latex, such as one of butadiene -1,3 and acrylonltrile, with a vinyl resin latex and a plastlcizer emul~lon, slnce many uses have been developed for b~ends of nltrile rubber latice3 and resinous vinyl latlce~, for example, for u~e in coating ~abrlc, ~articularly for ~se as a rein-for~.lng ply when coated on the underside of the fabric for ; floor covering materials, such as ^arpetlng. However, there are problems in adding the pla~ticizer durin~ the mixlng of the latices. me pla~ticiz~r soften~ the nitrile rubber latex during the drying stage and does not, to any satisfactory ex-tent, soften the vinyl resin latex during the drying stage.
As a result, the polyblend is sticky and difficult to handle.
To avoid thls undesirable phenomenon it is necessary to have a signiflcant portlon of the plasticlzer ln more intimate contact wlth the vinyl resin. Thus, it can be seen that a

-2- ~ ~
~1 '.

. ~ :

1040'774 process which would enable direction of the piasticizer to the vinyl resin portion-of the polyblend would be most desirable and beneficial.
SUMMARY OF THE INVENTION
We have unexpectedly found that plastic~zed poly-blends of nitrile rubber and vinyl resins can be prepared without the use of strenuous mixing and shearing action at high temperatures by employing a vinyl resin which has been prepared by polymerizing the vinyl monomer or monomers in the presence of a plasticizer therefor, said plasticizer being one that is compatible with the nitrile rubber employed in the polyblend. This polymerization process is referred to hereinafter as "plastimerization".
More particularly, the invention relates to a plas-ticized ~olyblend which comprises (a) a nitrile rubber, said nitrile rubber being a copolymer of a butadiene-1,3 hydrocarbon ; and an acrylic nitrile, (b) a vinyl resin which has been prepared by a procedure which comprises polymerizing a monomer which is a vinyl halide or a vinylidene halide or a mixture of a vi~yl halide and a vinylidene halide or a mixture of a vinyl or vinylidene halide with at least one other vinylidene ` monomer polymerizable therewith and having at least one terminal CH2 - C < grouping in the presence of up to 100 parts by weight, '' ~1 per hundred parts by weight of monomer, of a plasticizer for the ,~
vinyl resin, and (c) plasticizer for the vinyl resin, the plasticizer being compatible with the nitrile rubber and at least part of the plasticizer content of the polyblend being that plasticizer which was present during polymerization of said monomer.
The invention also relates to a process for making a plasticized polyblend comprising (1) polymerizing a vinyl, or ~ ~ - 3 -.

:

~: 104~'774 vinylidene~ halide with or without one or more vinylidene monomers having at least one terminal CH2 =C ~grouping in an aqueous medium containing a polymerization initiator and a plasticizer for the resultant polymer, (2) mixing the polymer -containing aqueous medium of (1) with a nitrile rubber l.atex containing a copolymer of a butadiene-1,3 hydrocarbon and an acrylic nitrile, and (3) mixing said mixture of (2) with a water-soluble coagulating agent to thereby coagula~ the plasticized polyblend .

DETAILED DESCRIPTION
In the present invention, "vinyl resin" refers to polymers and copolymers of vinyl and vinylidene halides, such as vinyl chloride, vinylidene chloride, and the like.
The vinyl halides and vinylidene halides may be copolymerized with each other or either may be copolymerized with one or more vinylidene monomers having at least one terminal CH2 = C < grouping. As examples of such vinylidene monomers .
may be mentioned, the o(, p -olefinically unsaturated car-~ boxylic acids such as acrylic acid,methacrylic acid, ethacrylic .;. 20 acid, ~ -chloroacrylic acid, o(-cyanoacrylic acid, and the like, , , .
esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyanoethyl acrylate, and the like: esters of methacrylic acid such as methyl methacrylate, butyl methacrylate, and the like: nitriles such as acrylonitrile and methacrylonitrile: acrylamides such as methyl acrylamide, N-methylol acrylamide, N-butoxy methacrylamide, and the like:
vinyl ethers such as ethyl vinyl ether, chloroethyl vinyl ether, and the like;

. ~.
~ -3a-, the vinyl ketones; styrene and styrene derivatives including - methyl styrene, vinyl toluene~ chlorostyrene, vinyl naphthalene, allyl and vlnyl chloroacetate, vlnyl acetate, vinyl pyridine, methyl vinyl ketone; dl-olefins including butadiene, isoprene, chloroprene, and the like; and mixtures of any of these types of monomers and other Yinylidene monomers copolymerizable therewlth including esters of maleic and fumarlc acid, and the like; and other vinylidene monomers of the types known to those skilled in the art. m e p~esent invention ls particularly applicable to the use of latices ln the polyblends wherein the resinous latex is made by tne polymerization, in the presence of a suttable plastlcizer therefor, of vinyl chloride or vinylidene chlor~de alone or in admlxture with one or more vinylidene monomers copol~mer-lzable there~ith in amounts as great as about 80% by welght~based on the weight of the monomer mixture. The most pre-ferred vinyl resin for use in the present ~nvent~on is polyvinyl chloride and the same will be descrlbed in connec-tlon therewith, it being understood that this is merely in-; tended in an illustrative sense and not limitative.
ffl e nltrile rubbers contemplated for use in the present invention are copolymers of a butadiene -1,3 hydro-carbon, by which is meant butadiene -1,3 and its hydrocarbon homologs, such as isoprene, and an acrylic nitrile, such as acrylonltrlle or methacrylonltrile. m e preferred n~trile rubber is a copolymer of butadiene -1,3 and acrylonitrile.
m e copolymers or nitrile rubbers may be prepared by any Or the known methods of preparing copolymers, although it has been found that copolymers prepared by emulsion polymeriza-tion give the best results, partlcularly when a nitrilerubber latex is to be employed in the polyblend, as will be seen from the description hereinafter. The copolymer ~04~ 774 may contaln other mater~als in small amounts either co-polymerlzed along with the butadiene -1,3 hydrocarbon ~nd the acrylic nitrlle or added after the polymerlzation. It is desirable that the copolymer be rendered as plastlc P,8 18 conslstent with high ultimate strength ~y mastication or by any other means, such as by the addltion thereto of a plasticizer for example, before use in the presentinventlo~.
ffle preferred copolymer contalns from ~bout 50 to 80~ by welght of a butadiene -1,3 hydrocarbon and 20 to 50~ by welght of an acryllc nitrlle slnce copolymers of this com-posltion are more compat~ble wlth the polyvlnyl chlorlde and the other polymers and copolymers recited hereinbefore, although copolymers higher in butadiene m~y be employed.
While the vlnyl polymers or resins used ln the poly-blenas Or the present invention may be prepared ~y the usual polymerizatlon reactions, they are pre~erably prepared by the emulslon polymerization technique ln an aqueous medium in the pre~ence of a plQsticizer for the partlcular vinyl polymer being prepared. Among the various plasticizers that may be 2C employed in making the vinyl polymers are the organi~
phosphoric esters, such as tricresy phosphate, trlphenyl phosphate, isodecyl dipheny phosphate, and the llke;
phthalic esters, such as dioctyl phtha'ate, dimethyl phth.a~ate, dibutyl phthalate, dilauryl phthalate, dimethyl tetrachlorophthalate, butyl phthalyl butyl glycollate, and the like. In fact, any known plasticizer for polym~rtc vinyl halides may be employed in the polymerization reaction It has been found thatlaO parts per hundrcd of mono~er of plastici~er 18 the maximum that can be chareed as a polymeri-zation ingredlent. When larger amounts are used, the polymerl-zation rate and the de~ree of conversion are adversely affected.
The aqueous medium used in maktng the vinyl polymers ~040774 by the emulsion polymerizatlon system may be emulsifier-free or it may contain an emulsifier. I~en emulsifiers are u~ed to prepare the vinyl polymer latices, the general types of anionlc and nonionic emulsiriers are employed. Excellent results have been obtained when using anionic emulsifiers.
Useful anionlc emulsifiers ~nclude alkali metal or ~mmonium salts of the sulfates of alcohols having from 8 to 18 carbon atoms, such as sodium lauryl sulfate, ethanolamine lauryl sulfate, ethylamine lauryl sul~ate, and the like; alkali metal and ammonium salts of sulfonated petroleum and paraffin oils; sodium salts of aromatic sulfonic acids, such as dodecane -1- sulfonic acid and octadiene -1- sulfonic acld; aralkyl sulfonates, such as sodlum isopropyl benzene sulfonate, sodlum dodecyl benzene sulfonate, sodium isobutyl naphthalene sulfonate, and the like; alkali metal and ammonium salts of sulfonated dicarbox~ylic acld esters, such as sodium dioctyl sulfosuccinate, disodium -n- octadecyl sulrosuccinamate, r and the like; alkali metal or ammonium salts Or free acid ~ of complex organic mono- and di-phosphate esters, and the ; 20 like. Nonionic emulsif~ers, such as octyl- or nonylphenyl polyethoxyethanol, may also be used. Vinyl polymer latices havlng excellent stability are obtained when employing the alkali metal and ammonium salts of aromatic sulfonlc acids, aralkyl sulfonates and long chain sulfonates.
When an emulslfier is used, the amo~nt may range up to about 6% or more based on the welght of the monomer or monomers belng polymerized. The emulsifier may be entlrely added at the start of the polymerizati~n or it may be added incrementally or by propoitioning throu~hout the run.
The vinyl polymer polymeri~ations are conducted at temperatures from about 20C. to about 70C. in the presence of a compound capable of initiating the polymerlzatlon. Free 104~774 radlcal inltlators are commonly used and they lnclude~ for example, the various peroxygen compounds, such as persulfates, benzoyl peroxide, t-butyl hydroperox~de, cumene hydroperoxide, t-butyl diperphthalate, pelargonyl peroxide, l-hydroxycyclo-hexyl hydroperoxide, and the l$ke; azo compounds, such as azodllsobutyro-nitrile, dimethylazodilsobutyrate~ and the like. Partlcularly useful initiators are the water-soluble peroxygen compounds, such as hydrogen peroxide and the sodlum, potassium and ammonium persulfates used by themselves or in an activated redox system. Typical redox systems ~nclude alkali metal persulfates ln combination with a reducing substance, such as sodium sulflte or sodium bisulrite, a reducing sugar, dlmethylamlno propionitrile, a dlazomercapto compound and a water-soluble ferrlcyanide compound, or the llke. Hea~y metal ions may also be used to activate the persulfate catalyæed polymerlzation. Partlcularly useful are alkall metal and ammonium persulfate. The amount of initlator used wlll generally be in the range between 0.1%
to 3.0% by weight based on the weight of the monomer or monomers and preferably between about 0.15% and 1.0% by weight. m e lnitiator may be charged completely at the out-set Or the polymerization. However, it is orten advanta~eous to employ lncremental addition or proportioning o~ the ini-tiator throughout the polymerlzation.
While the pH of the polymerization system J S not critical it is preferred that a pH of 7 or below be maintalned during the polymerization. mis is accompllshed by employing buffering agents in the reaction mixture, such as trlsodium phosphate, tetrasodlum pyrophosphate, and the like. m e vinyl polymer latex thus produced may subsequently be ad~usted to any deslred pH.
When using plastimerized vinyl resins in polyblends 104(1774 with n~trile rubbers and a plasticizer, as ln the present inventlon, it i8 possible to get much more plasticizer into the polyblend. Ranges of plasticizer levels from 5 to lOO
parts per hundred parts of total polymer can be obtained. Th18 includes both the plasticizer in the plastlmer1%ed polymer and that in the emulslon added to the blend. In those cases where no extra plastlclzer i8 required to achieve the deslred f~nal plasticizer level in the polyblend, n stabilizer emulsion 1~
the only material added to the latex blcnd. The plasticizer-stabllizer emulsion i8 made by any of the usual emulsionpreparatlon techniques which are well known to tho~e skilled ln the art.
After preparation of the plastimerized vlnyl resin latex, the nitrile rubber latex and the plasticizer emulsion, they are blended together in a physlcal hlend, as by ~tirring, ~nd the ~lke. The blend 80 formed will usually contain from about lO to 90 parts by weight of the nitrile ruhber latex and from about 90 to lO parts by wel~ht of the plastl~.erized vlnyl resln latex. mls blendlng procedure can be con-veniently carrled out at room te~peratur~ ln any sult~blevessel equipped with a suitable stlrrlng mea~s. Thereafter the blend 1~ coagulatod, separated and dried to rorm the polyblend. The coagulation step is accompl1she~ by pourin~
the aqueous blend mlxture into an aqueou~ solution of a sultable coagulating agent therefor. The most sultable coagulatlng medlum i8 ~n a~ueous solution of calcium ch~orlde, usually at a concentratlon of abo~t 3% to 10% by weight.
Other water-soluble coagulatlng agents ma~ be employed, such as the water-soluble salts of metal sulfates and metal chlorldes, for example, sodlum chlorlde, barlum chloride, aluminum sulfate, magnesium sulfate, and the llke. me coagulated polyblend is separated from the aqueous med~um by filtering, washing wltil soft water, and drying ln conven-tlonal equlpment, such as drylng ovens, ~ourdr~nler line, and the llke.
Heretofore the production of highly plasticized vinyl resin and nitrile rubber polyblend~, made via latex blending, was i~peded by the fact that the blends were too sticky to dry in conventional e~pment As potnted out above the stlckine~s was due to the presence of mo~t of the pla~ticlzer being ln the nltrile rubber phase of the blend.
In the polyblends of the present invention, whereln plasti-meri~ed vinyl resins are employed, sticklness ls no longer a problem. mis is so because the ratio Or pla~tlcl7er to nitrile rubber ls lowered sufflclently to a~oid stickiness.
Al~o, as a result of avoiding stickiness~ the polyblends of th present invention can be extrusion dried.
To further lllustrate the present, lnventlon, the followlng speclflc examples are given, it belng understood that thls is merely intended in an lllus~ratlve and not a llmltatlve sense. In the examples all parts and percents are by welght unless otherwlse indlcate~.
EXAMPLE I
This Exa~.ple lllustrates the prepar~tion of a nitrile rubber latex made ~rom butadiene -1,3 and acrylc-nltrile. m e copolymer was prepared in the form of a latex by emulsion polymerizatlon at 5C. accordin~ to the ~ollowing recipe:

_g_ . .

104(~774 Materlal Parts Butqdiene -1,3............................ ..74.7 Acrylonitri~............................. ..35.6 Emulsifier~ .. ,.................... ...4.6 Dlspersant(2 .......... ,,... ,....... ,. 0.1 Sodium ~ormaldehyde sulfoxylate.... ~.1 Cumene hydroperoxlde........ ........ ..Ø12 .Sequestered ~i~on.......... ........ ..Ø oo8 So~t water............. ,............ .1~5.0 ~l)Sod~um salt of abietlc acid.
~2)A polymerlzed sodium salt of an alkyl naphthalene sulfonic acld.
m e polymerlzation reaction wa~ continued until 85% of the monomeric mater~al had been converted to the copolymer, the reaction bein~ stopped by the use of the shortstopplne agent hydroxyl ammonlum sulfate (0.42 part). m e latex thus pro-duced had a total sollds content Or 30%.
EXAMPLE I~
In thls E~.a~ple thore ls lllustrated the prepara-tlon of the plastlmerized vlnyl chloride resln latex. The plastimerl~ed po;yvinyl chlorlde was prepared in the ~orm of a l~tex by emulslon polymeriz~tion at 45C, accordir,g to the followlns recipe:
Material Part~
So~t water... ,............... ,,,.. .200 Vlnyl chlorlde........ ,,.......... .100 Dl-octyl phthalate.... ,........... , 90 Sodium lauryl sulfate.,.. ..Ø9 Isopropyl percarbonate... ,,,.. ,,.,. 0.1 The polymerlzatlon reaction was continued until 75~ of the monomer had been converted to polyvinyl chlorlde. The latex thus produced had a total sollds content of 37.5%. Thls latex was designated Ex. II for suboequent ldentific~tlon.
A second plast~merized polyvinyl chlorlde latex was prepared uslng the above reclpe and polymerization con-dltions except that 63 part~ of dl-octyl phthalate per hundred parts of vinyl chloride were employed in place of 90 parts.
The latex so produced had a total solids content of 42~ and . , I -10-.
~ .
, ~040774 was designated Ex. II-A for subsequent ident1flcation.
EXAMPLE III
A blend of latices, for purposes of a po]yblend con-trol, was prepared aS follows: 2312 grams of the latex ~rom Example I was blended, at a p~ Or 10, with agitation, with 1864 grams of a polyvlnyl chlorlde latex, made ln the absence of plasticizer by a ~tandard emulslon polymerization reaction to give 38% total solids ln the latex. mereafter the polyblend was added to the following plasticizer emulsion whlch was made by homogenizing the following ingredlents:
Soft water............ .... 1500 grams Di-octyl phthalate.... ,............. .960 gra~.s Epoxidized soybean oll,............ , ~4 grams Cadmlum-barlu~ soap stabllizer,.... , 12 grams Organlc phosphite (chelator).......... 4 grams Sodium salt of dodecyl benzene sulfonate..........,.............................. 9~ grams me latex blend thus produce~ was then added to a solutlon of 334 grams of calcium chloride In '6 p~unds o~
soft ~ater at 50C. ln order to coagulate the polyblend. I~hen coagulation was complete, the brine w~s poured off and the polyb;end washed two times for 10 minut~s each with 3 ~allons of ~Ort water at a tcmperature of 27-30C. The polyblend was then formed lnto a sheet on a ~t~ndard sheet former and slleet press. m e crumbs of polyblend stuck ~ery badly to the ~creen, cloth and pre~s rolls and had to be scraped off. The poly-blend crumbs were vacuum dried on tray8.
EXAMPLE_IV
Two blends of lat1ces were prepared as fol;ows: (A~
2312 grams of the latex fro~ Ex~mple I was b]ended, with agi-tation, with 2240 grams of l~.tex Ex. II-A, at a p~ of 10, and (B) 2312 grams of the latex fro~ Example I was blended, also at a pH of 10 with agitation, wlth 2240 grams of latex Ex II.
ereafter, each of the polyblend~ (A) and (B) were added to ~eparate plasticizer emulsions, ea~h of which was made by homogenizing the following lngredients:

i040774 Soft water................ 496 gr~ms Di-octyl phthalate........ 456 grA~.s Epoxidized soybean oil..... 24 grams Cadmium-barium soap........ 12 gr~ms Sodlum salt of dodecyl ben~ene ~u~fonate,4.8 grams Each latex blend emulsion thus produced wa~ then added to separate solutions each contain~ng 364.16 grams of calcium chloride in 16 pounds of eort water at 50C. ~n order to coagNlate the polyblend~. When completely coagulated the polyblends were separated, washed and dried, in accordance with the procedure of Example TII. Each o~ the polyblend~
ran well on the sheet press and there wcre no sticking prob-lems, in contrast to the contr~l blend prepared as shown in Example III.
~XAMPLE V
m e po~yblends oP the prevlou~ Examples, namely, Control, Ex. II and Ex II-A, were compounde~ ~ith standard materl~l~, formed into sheets and testod to show the super~or results obtained in using a plastimerized v~nyl resin latex in the polyblend.
E~ch o~ the polyblends was mlxed on a roll ~ill ln accordance wlth the following recipe:
Materials Part~
~5 Polyblend.............................. ~00 Zlnc oxide............................. 5.0 Stearlc acid.............. ,,.. ,,.,..... 1.0 Carbon black.......................... 40.0 Tetra met~yl thluram di-L~ 30 sulflde (curing agent),.,,,,,,, 3.5 Rfter mlxlng, each compound w~s ~heeted out in a ~ standard sheeter and the sheets fr~m e~ch ~iXture were cured L ~ ~or periods of 5 mlnutes, 10 minut~s, and 20 minutes at 338F. After curing the sample~ were tested with the fol-lowlng results:

,. . .

H ~ ~ W u~l ~ O ~0 W ~0 , H
~ ~'~

H H
~o H

Lnoo u~oo u~ o .' r~ CV

i~ ~-r~ ~ $
"': ~ 0 ~ ~,,j r a ~ c ' aJ ~

' :
, ~<

~.
;:

It can be seen, from the above results, that the polyblends of the present invention have much higher tensile strength and elongation than previous polyblends and more importantly, are softer than prior polyblends of identical composition.
While it is preferred to form the p~lyblends of the present invention by blending latices of the nitrile rubber and the plastimerized vinyl resin, it is possible to blend the dired plastimerized vinyl resin with the nitrile rubber on a roll mlll. This is particularly true~Jwhen no additional plasticizer is to be added when making the polyblend.
The polyblends have a variety of uses such as in packaging, in cable ~acketing, and so forth. They are psrticularly useful where flexibility is needed, such as in films, coatings, such as inccoating fabricfi, non-wovens, and like substrates. Further, when non-flammable properties are deslred in the ent product~ it is a simple matter to choose a 8uitable plasticizer which will result in such properties.
More importantly, the polyblends of the present dinvention are ' very readily and easily transformed to finely divided powder form by standard procedures which results, not only in ease of handling and shipping~ but provides economic advantages in processing the same to the ultimate user or fabricator. Many other varied end uses and advantages will be apparent to those skilled in the art.
; While the present invention has beed described in te~m~ of its specific embodiments, certain modifications and equivalents will be apparent to those skilled intthe art and are intended to be included within the scope of the present , invention, which is to be limited only by the reasonable scope of the appented claims.

Claims (17)

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

1. A plasticized polyblend which comprises (a) a nitrile rubber said nitrile rubber being a copolymer of a butadiene-1,3 hydrocarbon and an acrylic nitrile, (b) a vinyl resin which has been prepared by a procedure which comprises polymerizing a monomer which is a vinyl halide or a vinylidene halide or a mix-ture of a vinyl halide and a vinylidene halide or a mixture of a vinyl or vinylidene halide with at least one other vinylidene monomer polymerizable therewith and having at least one terminal CH2 = C < grouping in the presence of up to 100 parts by weight, per hundred parts by weight of monomer, of a plasticizer for the vinyl resin, and (c) plasticizer for the vinyl resin, the plasticizer being compatible with the nitrile rubber and at least part of the plasticizer content of the polyblend being that plasticizer which was present during polymerization of said monomer.

2. A new composition as defined in claim 1 wherein the vinyl resin is polyvinyl chloride.

3, A new composition as defined in claim 1 wherein the nitrile rubber is a copolymer of butadiene-1,3 and acrylonitrile,

4. A new composition as defined in claim 1 wherein the plasticizer is di-octyl phthalate.

5. A new composition as defined in claim 1 wherein the vinyl resin is polyvinyl chloride and the nitrile rubber is a copolymer of butadiene-1,3 and acrylo-nitrile.

6. A new composition as defined in claim 1 containing plasticizer in addition to that in the vinyl resin.

7. A new composition as defined in claim 6 wherein the vinyl resin is polyvinyl chloride, the nitrile rubber is a copolymer of butadiene-1,3 and acrylonitrile, and the plasticizer is di-octyl phthalate.

8. A new composition as defined in claim 6 wherein the plasticizer is di-octyl phthalate.

9. A process for making a plasticized polyblend compris-ing (1) polymerizing a vinyl, or vinylidene, halide with or without one or more vinylidene monomers having at least one terminal CH2 = < grouping in an aqueous medium containing a polymerization initiator and a plasticizer for the resultant polymer, (2) mixing the polymer-containing aqueous medium of (1) with a nitrile rubber latex containing a copolymer of a butadiene-1,3 hydrocarbon and an acrylic nitrile, and (3) mixing said mixture of (2) with a water-soluble coagulating agent to thereby coagulate the plasticized polyblend.

10. A process as defined in claim 9 wherein the halide in (1) is vinyl chloride.

11. A process as defined in claim 9 wherein the nitrile rubber latex contains a copolymer of butadiene-1,3 and acrylonitrile.

12. A process as defined in claim 9 wherein the coagulat-ing agent is calcium chloride.

13. A process as defined in claim 9 wherein the plasticizer in (1) is di-octyl phthalate.

14. A process as defined in claim 13 wherein the resultant polymer in (1) is polyvinyl chloride.

15. A process as defined in claim 14 wherein the nitrile rubber latex contains a copolymer of butadiene-1,3 and acrylo-nitrile.

16. A process as defined in claim 15 wherein the coagulating agent is calcium chloride.

17. A process as defined in claim 9 wherein an aqueous emulsion of the plasticizer employed in (1) is mixed with the mixture of (2).