AU9737401A - Blends containing an interpolymer of alpha-olefin - Google Patents

Description

I. S&F Ref: 454566D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): The Dow Chemical Company 2030 Dow Center Midland Michigan 48674 United States of America James C Stevens Francis J Timmers Martin J Guest John J Gathers Pak-Wing S Chum Yunwa W Cheung Chung P Park George P Clingerman Kevin D Sikkema Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Address for Service: Invention Title: Blends Containing an Interpolymer of Alpha-olefin The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c I BLENDS CONTAINING AN INTERPOLYMER OF ALPHA-OLEFIN The present invention pertains to blends of aolefin/hindered vinylidene monomer interpolymers and vinyl aromatic polymers; foams therefrom and also foams from only a-olefin/hindered vinylidene monomer interpolymers. The blend components and their ratio were selected to provide superior performance and/or processability.

The generic class of materials covered by aolefin/hindered vinylidene monomer substantially random interpolymers and including materials such as a-olefin/vinyl aromatic monomer interpolymers are known in the art and offer a range of material structures and properties which makes them useful for varied applications, such as compatibilizers for blends of polyethylene and polystyrene as described in US 5,460,818.

One particular aspect described by D'Anniello et al.

(Journal of Applied Polymer Science, Volume 58, pages 1701-1706 (1995)) is that such interpolymers can show good elastic properties and energy dissipation characteristics. In another aspect, selected interpolymers can find utility in adhesive systems, as illustrated in United States patent number 5,244,996, issued to Mitsui Petrochemical 25 Industries Ltd.

**ee o. Although of utility in their own right, Industry is constantly seeking to improve the applicability of these interpolymers. Such enhancements may be accomplished via additives or the like, but it is desirable to develop technologies to provide 30 improvements in processability or performance without the addition oi additives or further improvements than can be achieved with the Saddition of additives. To date, the possible advantages of blending to provide materials with superior properties have not been identified.

There is a need to provide materials based on a- 35 olefin/vinylidene aromatic monomer interpolymers with superior performance characteristncs to the unmodified polymers, which will further expand the utility of this interesting class of materials.

The present invention pertains to a blend of polymeric materials comprising from about 1 to about 99 weight percent of at least one interpolymer comprising from about 1 to about 65 mole percent of at least one vinylidene aromatic monomer, or at least one hindered -1p I. It aliphatic vinylidene monomer, or a combination of at least one vinylidene aromatic monomer and at least one hindered aliphatic vinylidene monomer, and from about 35 to about 99 mole percent of at least one s aliphatic a-olefin having from 2 to about 20 carbon atoms; and from about 1 to about 99 weight percent of at least one homopolymer of one or more vinylidene aromatic monomers, or at least one interpolymer of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene monomers, or at least one of or which additionally contains an impact modifier, or a combination of any two or more of or (3) The present invention also pertains to expandable compositions comprising at least one blowing agent; and (II) at least one interpolymer or blend of interpolymers comprising from about 1 to about 100 percent by weight of at least one interpolymer comprising from about 1 to about 65 mole percent of at least one vinylidene aromatic monomer, or at least one hindered aliphatic vinylidene monomer, or a combination of at least one vinylidene aromatic monomer 25 and at least one hindered aliphatic vinylidene monomer, and from about 35 to about 99 mole percent of at least one aliphatic a-olefin having from 2 to about 20 carbon atoms; and from 0 to about 95.5 percent by weight of at least one -homopolymer of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene monomers, or at least one interpolymer of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene 35 monomers and optionally one or more polymerizable ethylenically unsaturated monomers other than a more vinylidene aromatic monomer or more hindered aliphatic vinylidene monomer.

t 2a The present invention also pertains to a blend of ploymeric materials comprising from 35 to 99 weight percent of at least one interpolymer comprising from 1 to 65 mole percent of at least one vinylidene aromatic monomer, or at least one hindered aliphatic vinylidene monomer, or a combination of at least one vinylidene aromatic monomer and at least one hindered aliphatic vinylidene monomer, and from 35 to 99 mole percent of at least one aliphatic a-olefin having from 2 to 20 carbon atoms; and from 1 to 65 wieght percent of at least one homopolymer of one or more vinylidene aromatic monomers or at least one interpolymer of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene monomers, or 15 at least one of or which addidiotionally contains an impact modifier, or a combination of any two or more of(1), or *ooo The present invention also pertains to foamable compositions comprising at least one blowing agent; and (II) at least one interpolymer or blend of interpolymers comprising s from 1 to 100 percent by weicht of at least one in.eroolymer comprising from 1 to 65 mole percent of at least one vinvlidene aromatic monomer, or at least one hindered alihatic vinylidene monomer, or a ccmbination of at least one vinylidene aromatic mcnomer and at least one hindered aliphatic vinyvide.e monomer, and from 35 to 99 mole percent of at least one aliphatic aolefin having from 2 to 20 carbon atoms; and from 0 to 95.5 percent by weight of at least one homool',er is of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene monomers, or at least one interpolymer of one or more vinylidene aromatic monomers and/or one or more hindered aliphatic vinylidene monomers and optionally one or more colymerizable ethylenically unsaturated monomers other than a more vinylidene aromatic monomer or more hindered aliphatic vinylidene monomer.

The blends and foamable materials of the present invention 'can comprise, consist essentially of or consist of any two or more of such interpolymers enumerated herein. Likewise, the interpolymers can 25 comprise, consist essentially of or consist of any two or more of the enumerated polymerizable monomers.

These blends provide an improvement in one or more of the polymer properties such as, but not limited to, mechanical performance and/or melt processability.

The term "interpolymer" is used herein to indicate a polymer wherein at least two different monomers were polvmerized to make the interpolymer.

The term "substantially random" in the substantially random 35 interpolymer comprising an a-olefin and a vinylidene aromatic monomer or hindered aliphatic vinylidene monomer as used herein means that the distribution of the monomers of said interpolymer can be described by the Bernoulli statistical model or by a first or second order Markovian statistical model, as described by J. C. Randall in POLYMER SEQUENCE DETERMINATION, Carbon-13 NMR Method, Academic Press New York, 1977, pp.

71-78. Preferably, the substantially random interpolymer comprising an S I at-olefin and a vinvlitee aromat-ic moncmer' does no:: contain mnore than percent of the total mu. of *nylidene~e aroma tic 7monomer i lcso vinylidene aromatic mnerof more than 3 units preferably, the interpolymer was no: c*-rc-ezed by na" h deor isotacticity or ynltcii.' Thi-s means thnat_ z: e1 c r spectrum of the substantial>, randoIM ilneroolvme- peak ares corresponding to the main chain m~h -eand met-n carbons representing either m.eso c Iao seauences_ or racemiz d-iad secuences should not exceed 75 pe rcen:_ of 7the total pea-: ar ea of th main can Met-hvlene and methine carbons.

Any num-erIcal- recite: r a -1-1 values from the lower value_ to th-e upcer _a'u n icrements of one Jprovided that there a separa:_-on orf a: least 2 unizs between anv lower value and any n-aI her value. as an- example, is stated ta is the amount of a compcnen:o or a *:-alue of a process variable sucn- as, -for example, temperatur-:e, cressure, time is, f-or example, fro_-m 1 to preferably from 22_ to 30, more prerferably from 31, to 70, iz is intended that values Such as 15 to 85, 2?to 68, 43 t~o 51, 30 to 32 are exoressly enumerat:ed in thIs smeciflr-ation 7cr values hchare less than one, one unct; considered zo be 0.0001, 0.001, 0.01 or 0. 1 as appropriate. These are only examples of what is speci fically intended and all possi-ble combinations of numerical values between the lowest value and the h-ighest value enumnerated are to be considerd to be expressly stated in this application in a similar manner.

The interolvners s-uitable for use as component to make the blends comprising the present invention include, but are not limited to, interpolymers prepared by poiymerizing one or more aolefins with one or mocre vinylid me aromatic monomers and/or one or more hindered aliphati--c vinylidene monomers.

Suitable ct-olefins include for example, those containing from 2 to 20, preferao=iy from 2 to 12, more preferably from 2 to 3 .carbon atoms. Particularly suitable are ethylene, p~ropylene, butene- 1, 4 -methyl-l-pentene e:en- and oczene-l.

Suitable 7inyl idene aromatic: monomers include, for example, 35 those represented by tefollowing formnula I: ormula I Ar R- C QR a.

wherein RI is selected from the grouc of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms, preferably hydrogen or methyl; each R, is independentlv selected from the grouo of radicals consis:in of hvdrooen and alkyl radicals containing from 1 to 4 carbon atoms, preterably hydrogen or methyl; Ar is a phenyl group or a piey group substituted with from I to suostituents selected from the grouc ccnsisting of halo, C 4 -alkl, and CI- 4 -haloalkyl; and n nasa value from zero to 6, preferablv from zero to 2, more preferably zero. Exemclary n onovinvlidene aromacic i0 moncmers include styrene, :inyl toluene, c-.methvYlstvrene, t-bul; styrene, chlorostyrene, incucing all isomers of these ccnccunds.

Particularly suitable such moncmers inClube stvrene and icwer aik1lor halogen-substicuted derivatives thereof. Preferred mcncmers include styrene, a-methyl styrene, the lower alkyl- or 1phenl-ring is substituted derivatives of styrene, such as ortho-, meta-, and caramethylstyvrene, the ring halocenated styrenes, cara-vinyl toluene or mixtures thereof. A more preferred monovinylidene aromatic monomer is styrene.

By the term "hindered aliphatic or cycloaliphatic vinylidene monomers" is mean: addition col-m.erizable vinvlidene monomers corresponding to the followinc formula II: "Formula II

I

RI -C C(R2)2 wherein and Al is a sterically bulky, aliphatic substituent of uo to 0.

20 carbons,

R

1 is selected from the group of radicals consistin of consisting o hydrogen and alkyl radicals containing from 1 to 4 carbon atoms, preferably hydrogen or methyl; each R- is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to 4 carbon atoms, preferably hydrogen or methyl; or 30 alternatively R' and Al together form a ring system. By the term "sterically bulky" is meant that the monomer bearing this substituent is normally incapable of addition polymerization by standard Ziegler- Nblatta polymerization catalysts at a rate comparable with ethylene polymerizations. Preferred hindered aliphatic or cycloaliphatic vinylidene monomers are those in which one of the carbon atoms bearing ethylenic unsaturation is tertiary or quaternary substituted.

Examples of such substituents include cyclic aliphatic groups such as cyclohexyl, cyclohexenyl, cyclooctenyl, or ring alkyl or aryl substituted derivatives thereof, tert-butyl, or norbornyl. Most preferred hinde red aliphatic vrinylidc:ene comcouncjs are nl cvclohexane and the various isomeri: vin,/l- ring substitte derivatives of cyciohex<ene and substi tuted cvclohe:xenes, and etvidene-2-norbornene Especiall-i suitable is vi rY- Le~n The interool vmers of- on-2 or more c-oef in_- d one or more Monovn,lidene aromatic mcomers aF~'rone o)r more nordalichatIc or cyclpai vinyli dene mcnomers enclove- in th-e creSent in 'ention are substantiaw,j random -Ov7 o.rers. These '.,'oooMe rs usually contain from 1 to crfrl fro f to 60 ao erb1 :rcm. 10 to 55 mole percent of at least on e ,Ln*/ljiene arometic m.ioncme r and,'cr hindered aliphatic or vlaihtr ~dn n -rom 31c to 99, preferably from 40 to ra;,mre ore. -era I: from :r t 0 mole cercent of at least on e alipnati c a-olefin havir.. fomi 2 to carb-on atoms.

The num-ber average molecular ,;eiqhrz (M n) of th*-ese in teroolvmers is usually greater than 1,000, preferabi>: frm5,000 to 1,00,0,000, more preferably from 10,000," to 300,000.

The present invention croviideS blends of rove components of molecular weight and composition disraoc*_tlons selected ot.3 obtain an overall molecular weight and composition ho'stribution which gives enhanced properties or processabilitv.

The blends of the present invention comorose from 1 to 99, preferably from 3 to 97, more preferably from 5 to 95 percen~t of component by weight and from 99 to 1, preferably from 97 to 3, more preferably from 95 to 5 percent of comoonent bvw-..eioht.

*Those blends of the present_ invention containing from 33 to 99, .preferably from 40 to 97, more oreferablv from 60 to 95 cercent or component by weight and from 65 to 1, preferably from 6-0 toabout more preferably from40 to 5 percent of- component cv weight are of particular interest in that in some instances, the', Possess much improved properties when compared to those blends contai.ning less than percent by weight of component While preparing the substantially random in~erpolymers, component as will be described hereinafter, an amountr of atactic viny/liden e aromatic homooolvmer may be formed due to homooolyerization *.of the vinylidene aromatic monomer. Tn general, the higher the polymerization temperature, the greater the amount of homopolymer fo0rmed. The presence of vinylidene aromatic honopoiwmer is in general not detrimental for the purposes of the present invention and may be tolerated. The vinylidene aromatic homopolymer may be separated from the interpolymer, if desired, by extraction techniques such as selective precipitation from solution with a non solvent for either the interpolymer or the vinylidene aromatic h.mooolymer. For -e Puroose of the present invention it is preferred that no more than 20 ;;eight percent, preferably less than 15 weight percent based on the total weiht of the interpolymers of vinylidene aromatic homo olyer is present in the interpolymer blend component.

Thie substantially random inferpolymers may be mrdified by typcical graftin, hydrogenation, functionalizing, or other reactions well known to those skilled in the art. The polyers may be readilV sulfonated or chlorinated to crovide func i 1nalized4 -sr- s according to established technic:es.

The substantially random in'ernci. ers can be Croduced b: Polymerization In thne presence of a metallocene or conse geometry catalyst and a co-catalyst as described in James C. Stevens et al. and US Patent No. 5,703,137 by Francis j.

is Timmers. Preferred operating conditions for such polymeriz- on reactions are pressures from atmospheric up to 3000 atmoscpneres and temperatures from -30 0 C to 200'C. ?olvmeriztcons and unreaced monomer removal at temperatures above the autopolymerization temperature of the respective monomers may result in formation of some amounts of hcmopolvmer polymerization products resulting form free radical polymerization.

Examples of suitable catalysts and methods for preparing the substantially random interpolymers are disclosed in EP-A-514,828; as ~well as U.S. Patents: 5,055,438; 5,057,475; 5,096,867; 5,064,802; 5,132,380; 5,189,192; 5,321,106; 5,347,024; 5,350,723; 5,374,696; 5,399,635; 5,470,993; 5,703,187; and 5,721,185.

The substantially random a-olefin/vinylidene aromatic interpolymers can also be prepared by the methods described by John G.

Bradfute et al. R. Grace Co.) in WO 95/32095; by R. E. Pannell 30 (Exxon Chemical Patents, Inc.) in WO 94/00500; and in Plastics Technology, p. 25 (September 1992).

Also suitable are the substantially random interpolymers which possess at least one a-olefin/vinyl aromatic/vinyl aromatic/a-olefin tetrad disclosed in WO 98/09999. These interpolymers contain S 35s additional signals with intensities greater than three times the oeak to peak noise. These signals appear in the chemical shift range 43.75-44.25 ppm and 38.0-38.5 ppm. Specifically, major peaks are observed at 44.1, 43.9 and 38.2 ocm. An Attached Proton Test (APT) NMR experiment indicates that the signals in the chemical shift region 43.75-44.25 ppm are methine carbons and the signals in the region 38.0-38.5 ppm are methylene carbons.

In order to determine tne carbon-13 'i!P chemical shifts of these interpolvmers, the F ollowinoc procedures and conditions are emo.iloved.

A f ive to ten weig cercent polymer solution is prepared in- a mi:xture consisting of 50 voclume percent 1,1,2, Z-tetrachl vlum Decen 0.0 "olar c-romium tris~acetvlaceronate) n124 trichlorobenzene. <K'R scec--ra are acc:ired at 130'C using an 1 es gated decoupling secuence, a 900 culse width and a pulse delay of five seconds or more. 7-e spectra are referenced to thne isolatedmthle signal of the Poly-er ass 7red at 3 0. 00 0 rDom.

It is believed that these new,- siznals are due to sequences ;nvoivincg tw.-o head-to-tail vniaro-ma:t c monomer creceded and followed by at least: one a-olefn inisert-ion, ecg. an ethylene/stylrene/sz:yt-ren/e:hvi,-'en-e tetrad wherein tn'e styrene mcom-r insertaons of said t-etrads occur exclusivelv in a 1,2 (head to tail) manner. it is understood one skilled in the art that for such tetrads involving a vinyl aromatic monomer other than styrene and- an ct-olefin other than ethylene that the a-olefin/viny aroat monomer/v-invl aromatic moncmer/ax-oLefin tetrad wilgive rise to similar carbon-13 iN!R oeaks but with slihtly different CnIemi-c-a: shifts.

These interpoclym-Iers are prepared by conducting the polymer i:a t ion at temperatures of from about -30'C to 250'C in the presence of such catalysts as those represented by the formula

CP/

wherein: each Cp is independently, each, occurrence, a substituted 25 cyclopentadienyl group it-bound to m; E is C or Si; M is a group TI1 metal, preferably Zr or Hf, most preferably Zr; each R is S S.*independently, each occurrence, H, hydrocarbyl, silahydrocarbyl, or hydrocarbylsilyl, containing up to 30 preferably f-rom 1 to 20 more preferably from 1 to 10 carbon or silicon atoms; each R' is independently, each occurrence, H, halo, hydrocarbyl, hyrocarbyloxy, silahydrocarbyl, hydrocarbylsilyl containing up to 30 preferably from 1 to 20 more preferably from 1 to 10 carbon or silicon atoms or two R' groups together can. be a hydrocarbyl substituted 1, 3-butadiene; m is 1 or 2; and optionally, but preferably in the presence of an activating cocatalyst. Particularly, suitable substituted cyclopentadienyl groups include those ill1ustrated by the formula: (R)4 -inerein each R is indecenziently, each ccurrenice, H, yv rc-y zilahvd-rocarbvl, or hydrocarbyis ilvi, cta .inna uc to 30 creferablv from 1 to 20 more preferably from 1 to 10 carbon or silicon ato-ms or two R. groups together form a divalentc derivatiye of suc. coc.

7zre ferably, R needntiv each occur:-_ce s indeednclu d ne r e appropriate all isomers) hnydrooen, methyl, etyprocy-, rt~ cent vL, hexvl, benzvi, ohenv: or silyl r (w'Cere aocrooDri a-e) tw,.o sum' -groucs are linked tocethner forming a fused ring system, sum as :ndenyl, fluorenyl, tetrahi.vdroinevJtayrfur~; or octahydrofluorenyl, or substituted deriy.-atives of these f'used ring -vs tems.

Particularly preferred catalysts include, for examole,1 acemic- (dimethylsilan-edivl') -bi-s- 2-methvl..-4-chenyli-nden,!) zir:con)Iumn dichioride, racemic-(dimethyl-ivsianediv/I) i s -methvl -4 pDhenyl indenyl) z ircon ium 1, 4 -d iphenyl -1 3-bu tadiene, racemi alkyl, racemic- (dimethyls ilanediyl) -bis- (2-methvl -4-cheny IindenylI) zirconium di-C 1 4 alkoxide, or any combination thereof.

20 Further preparative methods for the interpolymer blend component of the present invention have been described in the literature. Longo and Grassi (Makromol. Chem., Volume 191, pages 2337 to 2396 (1990]) and D'Anniello et al. (journal of Applied Polymer Science, Volume 58, pages 1701-1706 (1995)) reported the use of a catalytic system based on methylalumoxane (MAO) and *cyclopentadienyltitanium trichioride (CZ)T iC 3 to prepare an ethylenestyrene copolymer. Xu and Lin (Polymer Preprints, Am.Chem.Soc.,Div.

Polym. Chem. Volume 35, pages 68 6, 637 1994] have reported copolymerization using a TiCl 4 /NdCl 3 /Al -4u) 3 catalyst to give random copolymers of styrene and propylene. Lu et al (journal of Aoolhed Polymer Science, Volume 53, pages 1453 to 14 60 (1994] have described the copolymerization of ethylene and styrene using a TiC1 4 /NdCl,/ Mg9CI :/Al(Et) 3 catalyst. The manufacture of a-ole fin/vinyl aromatic monomer interpol-mers such as propylene/styrene and butene/styrene are described in United States patent number 5,244,996, issued to Mitsui Petrochemical Industries Ltd.

The polymers of vinylidene aromatic monomers employed as component in the present invention include homopolymers of a single vinylidene aromatic monomer or interpolymers prepared from one -9or more vinylidene arcmat-c monlomer,. ?ar-ticularl, sui table are monovinylidene aromatic mcnom-ers.

Suitable noo:nlore~oatic oolym.ers for use in ccoonent of the oresei- wnssrdo foamabie coDmocsitions i-CIL-4e hcmooolymers or interocivm-11ers or one or mOre monovinlYlidene ao mnonomers, or an interco!±,-er o7 One Of mnore monovin-idene aromatic monomers and one or more 77onomers i:e_rooltmerizabie Therewith other than an aliphatic cx-olefin. Suitable monov;inylidene aromatic monomners are reoresented by the followG tf:)orm_ 1a: Ar R'C Cl-, wherein R 1 is selected from thle crouc of radicals consisting of hv%,drocen and hyd rocarbyl radicals co~ntaininc th-ree carbons or less, and A-r is a phenyl group or a phenyl croup s ubst:_:uted with from I to 5 sbtteo selected from the group consisting of halo, C._ 4 -alkvl, an-d haloalk,l. Exemolary no noviinvii-cene E-romatroc monomers include styrene, para-vinyl toluene, :-en~tvee -butyl styrene, chi1orostCyrene, including all isomers of these cornccunds. Stvrene is a oarticularl./ desirable monovinylidene aromatic monomer for the monovinylidene aromatic polymers used in the practice of the present invention.

Examples of suitable inter-po lymerizable comonomers other than a monovinylidene aromatic monomer- include C, C 6 conjugated dienes, especially butadiene or isoprene, N-phenyl maleimide, 'N-allyl maleimide, acrylamide, ethylenically-unsaturated nitrile monomers sucn as acrylonitrile and methacrylonitrile, ethylenically-unsaturated mono- 5 and difunctional carboxylic acids and derivatives thereof such as esters and, in the case of difunctional acids, anhydrides, such as acrylic acid,- CI--alkylacrylates or methacr-ylates, such as n-butyl acrylate and *methyl methacrylate, maleic anhydride, or any combination thereof,

I

some cases it is also desirable to copolymerize a cross-linkino monomer 30 such as a divinyl benzene into the monovinvlidene aromatic polymer.

The polymers of monovinyliden e aromatic monomers with other interpolymerizable comonomers pre ferably contain, polymerized therein, at least 50 mole percent, preferablv at least 60 mole percent, and more preferably at least 70 mole percent of one or more monovinylidene aromatic monomers.

Component B may also be a flame resistant rubber modified stvrenic blend composition. The flame resistant compositions are typically produced by adding flame* retardants to a high impact polystyrene (HIPS) resin. The addition of flame retardants lowers the impact strength of the HIS which is restored back to acceptable levels by the addition of impact modifiers, typicallv stvrenebutadiene (SES) block coColvmers. The final compositions are referred, to as ignition resistant Tri'stvrene, IRPS. The IRS comnosit i ons s tyPically contain the follwing components: Component Q) from 5 to 90 percent bw eight based cOn toa resin composition of a rubber modified polyter derivd from a vinyl aromatic monomer,

IS,

Componen: S) a suffirient amounc of halogen-cntainin flm retardant to provide the ccmzosition with 7 to 14 ero a-n b weight halocen, Component T) from 2 t 6 cenrt weit based on tctal resin composition (RS+T+U) of an. icranic flame retardant synercis, and Component U) from 1 to 8 percent by weicht based on total resin composition of an. impact modifi Component R is a rubber modified vinl aromatic polymer.

Suitable polymers include tose nmade from vinyl aromatic monomers typically represented by t-e formula:

R

Ar-C=CH, wherein R is hydrogen or metchyl, Ar is an aromatic ring structure having from 1 to 3 aromatic rings with or without alkyl, halo, or haloalkyl substitution, wherein any alkyl group contains 1 to 6 carbon atoms and haloalkyl refers to a halogen substituted alkyl groun.

Preferably, Ar is phenyl or alkylphenyl with henyl being most creferred. Typical vinyl aromatic monomers which can be used include: styrene, alpha-methylstyrene, all isomers of vinyl toluene, esoecially para-vinyltoluene, all isomers of ethyl styrene, propyl styrene, vinyl biphenyl, vinyl naphthalene, vinyl anchracene, and mixtures thereof.

The vinyl aromatic monomer may also be combined with other o copolymerizable monomers. Examples of such monomers include, but are not limited to acrylic moncomers such as acrylonitrile, methacrylonitrile, methacrylic acid, methyl methacrylate, acrylic acid, and methyl acrylate, maleic anhydride, maleimide, and phenylmaleimide.

35 Rubber modified vinyl aromatic polymers can be prepared by polymerizing the vinyl aromatic monomer in the presence of a predissolved rubber to prepare impact modified, or grafted rubber containing products, examples of which are described in USP's 3,123,655, 3,346,520, 3,639,522, and 4,409,369. The rubber is typically a butadiene or isoprene rubber, preferably polybutadiene.

Preferably, the rubber mcdiie vin,1l a romatic oolvmrer ;s hiah moc polystyrene

(HIPS).

The amount of r ,,bber modifiedi vinyl aromatic Dclv-mr use d in the composition of the presen t inven-tion is typically; from 50 to oreferably from 62to 33-3, more :Dref er-ablv fro- 0t creferablv from 72 t:32, cercent by wegtbased on tota l resin composition RSTp Commonent- U iJs an fier wh1,,ichn can be any polym7er which w.,ill increase t he imp, act: strenqoth of the compositi on o h present invention. 4 ca I i m na ct m cd i fi ers cnIlude pc y bu tadie polyisorene, and ccroolymers co- a vinyil aromatic oomrano a conjugated diene, e.c. styrene-butadiene copolymers, strn-iorn copolym,-ers, includino iick and tribl1ck Ccoivmers. Othe 7imaCt modifiers include ccolym,-ers or a vinvl aromatic monomer wt hydrogenated dienes, ethvlene-acrylic acid copol ymers and ethylenestyrene copolymers. Preferably, the imcact modifier is a styrenebutadiene-s tyrene tribiock cocoivmer cctaingn from-. 25 to 40, weight percent styrene component.We an erhvliene/styrene interpolymer is employed as the impac:: modifier, the blend of the ethylene/styrene interpolvmer and the poytrn sa bClend of the pr"esent invention.

The amount or impact modifier used in the composition of the present invention is typically frcm 1 to 6, preferably from 1 to 7, more preferably from 2 to 6, and most preferably from 2 to *...percent by weight of total resin composition 25 Component S is a Flame retardant which can be any halogencontaining compound or mixture of compou nds which imparts flame resistance to the composition of the Present invention. Suitable flame retardants are well-k-nown in the art and include but are not limited to hexahalodichen yl eth-ers, octahalodiphenyletrs decahalodiphenyl ethers, decahalobiphenyl ethanes, 1, 2bis (trihalopheno(y) ethanes, 1, 2-bis (pent ahalopheno:y) ethanes, hexahalocyclododecane, a tetrahalobisp.enol.A ethylene(N, N')-bistetrahalophthalimides, tetrahaicphthali. anhydrides, hexahalobenzenes, halogenated indanes, halogenated phosphate esters, halogenated paraffins, halogenated polystyrenes, and polymers of halogenated bisphenol-A and epichlorohydrin, or mixtures thereof. Preferably, the flame retardant is a bromine or chlorine containing compound. In a preferred embodiment, the flame retardant is decabromodiphenyui ether or a mixture of decabromodiphenyl ether .Iith tetrabromobisphenol-A Theamount of flame retardant present within the composition of the present invention will depend upon the halogen content of the specific flame retardant used. Typically, the amount of flame retardant is chosen s-uh that from 7 to 14, preferably from 7 to 13, more preferably from to 12 and most preferably from 9 to 11 percent by weight of total resin composition of halogen is present in the composition of the present invention.

Component T is an inorganic flame retardant synergist which are known in the art as compounds which enhance the effectiveness of flame retaria.ts, especially halogenated flame retardants. Examples of inor_ nic flame recardant synergists include but are not limited to metal c::ides, e.g. iron oxide, tin oxide, zinc io oxide, aluminum trioxide, al.ina, antimony tri- and pentoxide bismuth oxide, molybdenum tri3ife, ar. tungsten trioxide, boron compounds such as zinc borate, ancimony silicates, ferrccene and mixtures thereof.

The amount of incrganic flame retardant synercist present is typically from 2 to 6, preferably from 2 to 5, more preferably from to 5 and most preferably from 2.5 to 4 percent by weight of total resin composition The compositions of the present invention may also contain minor amounts of typical processing aids such as mold release agents, plasticizers, flow promoters, e.g. waxes or mineral oil, pigments, thermal stabilizers, UV stabilizers, antioxidants, fillers, e.g. glass fibers, and glass beads.

The composition can be produced by any blending or mixing .technique which will result in a generally uniform dispersion of all 25 ingredients throughout the resulting product. Illustrative devices include Banbury mixers, compounding rolls, single screw extruders, and twin screw extruders. Additionally, the components of the composition can be combined in an apparatus such as a dry blender before being fed a mixing/melting extruder apparatus, or two or more of the 30 ingredients may be pre-mixed and fed into a hot melt of the remaining components.

Suitable homopolymers and interpolymers which can be employed in the foam compositions of the present invention include those enumerated above plus interpolymers prepared from one or 35 more vinylidene aromatic monomers and/or one or more one hindered aliphatic vinylidene monomers and optionally, one or more S"polymerizable ethylenically unsaturated monomers different from those enumerated in Suitable such polymerizable ethylenically unsaturated monomers include, for example, ethylenically unsaturated monocarboxylic acids having from 3 to 8, preferably from 3 to 6, more preferably from 3 to 4 carbon atoms; anhydrides of ethylenically unsaturated dicarboxylic acids having from 4 to 10, preferably from 4 to 8, more preferably fronm 4 to 6 carbon atoms; esters of ethylenically unsaturated monocarboxylic acids; ethylenically unsaturated nitriles; or any combination thereof. Particularly suitable such monomers include, for example, acrylic acid, methacrylic s acid, methyl acrylate, methyl methacrylate, echyl acrylate, ethyl meinacrylate, propyl acrylae, propyi methacrylate, butyl acrylae, butyl methacrylate, maieic anhydride, acrylonitrile, metharylonitrile or any combination thereof. The interpolymers can contain from zero up to 50, preferably up to 40, more creferably up to 30 weight perceni of such monomers which are different frcm zte monomers of The blends of the presen inven.-ion may be prepared by an/ suitable means known in the art such as, but not limited to, dry blending in a pelletized form in the desired proportions followed by melt blending in a screw extruder, or Banbury mixer. The dry blended pellets may be directly melt processed into a final solid state article by for example injection molding. Alternatively, the blends may be made by direct polymerization, without isolation of the blend components, using for example two or more catalysts in one reactor, or by using a single catalyst and two or more reactors in series or parallel.

An example of making the blend directly by polymerization is an in-reactor blend method as described in U.S. 4,168,353. That is, styrene monomer is impregnated into granules of an interpolymer blend component suspended in a suitable liquid medium and grafts5 polymerized. The resultant blend granules are cooled and discharged from the vessel.

The present foam structure may take any physical configuration known in the art, such as sheet, plank, or bun stock.

Other useful forms are expandable or foamable particles, moldable foam 30 particles, or beads, and articles formed by expansion and/or coalescing and welding of those particles.

Teachings to processes for making and processing ethylenic polymer foam structures are in C. P. Park, "Polyolefin Foam", Chapter 9, Handbook of Polymer Foams and Technology, edited by D. Klempner and 35 K. Hanser Publishers, Munich, Vienna, New York, Barcelona (1991) The foam may result from subjecting the foamable compositions to foaming conditions and be made by a conventional extrusion foaming process. The structure is generally prepared by heating a polymer material to form a plasticized or melt polymer material, incorporating therein a blowing agent to form a foamable gel, and extruding the gel through a die to form the foam product.

Prior to mixing with the blowing agent, the polymer material is heated to a temperature at or above its glass transition temperature or melting point. The blowing agent may be incorporated or mixed into the melt polymer material by any means known in the art such as with s an extruder, mixer, or ble.der. The blowing agent is mixed with the melt polymer material at an elevated pressure sufficient to prevent substantial expansion of the melt polymer material and to generally disperse the blowing agent homogeneously therein. Optionally, a nucleator may be blended in the polymer melt or dry blended with the polymer material prior to plasticizing or melting. The foamable gel is typically cooled to a lower temperature to optimize physical characteristics of the foam structure. The gel is then ex:ruded or conveyed through a die of desired shape to a zone of reduced or lower pressure to form the foam structure. The zone of lower pressure is at is a pressure lower than that in which the foamable gel is maintained prior to extrusion through the die. The lower pressure mav be superatmospheric or subatmospheric (vacuum), but is preferably at an atmospheric level. By this process, plank, sheet, rod and tube-shaoed foam products are prepared.

The present foam structure may be formed in a coalesced strand form by extrusion of the ethylenic polymer material through a multi-orifice die. The orifices are arranged so that contact between adjacent streams of the molten extrudate occurs during the foaming process and the contacting surfaces adhere to one another with 25 sufficient adhesion to result in a unitary foam structure. The streams of molten extrudate exiting the die take the form of strands or profiles, which desirably foam, coalesce, and adhere to one another to-form a unitary structure. Desirably, the coalesced individual strands or profiles should remain adhered in a unitary structure to 30 prevent strand delamination under stresses encountered in preparing, shaping, and using the foam. Apparatuses and method for producing foam structures in coalesced strand form are seen in U.S. Patent Nos.

3,573,152 and 4,824,720.

The present foam structure may also be formed by an 35 accumulating extrusion process as seen in U.S. Pat. No. 4,323,528. In this process, low density foam structures having large lateral crosssectional areas are prepared by: 1) forming under pressure a gel of the ethylenic polymer material and a blowing agent at a temperature at which the viscosity of the gel is sufficient to retain the blowing agent when the gel is allowed to expand; 2) extruding the gel into a holding zone maintained at a temperature and pressure which does not allow the gel to foam, the holding zone having an outlet die defining an orifice opening into a zone of lower pressure at which the gel foams, and an openable gate closing the die orifice; 3) periodically opening the gate; 4) substantially concurrently applying mechanical s pressure by a movable ram cn the gel t eject it from the holdina zone through the die orifice into the zone of lower pressure, at a rate greater than that a- which substantial foaming in the die crifice occurs and less than that at which substantial irregularities in cross-sectional area or shape occurs; and 5) permitting the ejected gel to expand unres:rained in at least one dimension to produce the foam structure.

The present foam structure may also be formed into noncrosslinked foam beads suitable for molding into articles. To make the foam beads, discrete resin particles such as granulated resin is pellets are: suspended in a liquid medium in which they are substantially insoluble such as water; impregnated with a blowinc agent by introducing the blowing agent into the liquid medium at an elevated pressure and temperature in an autoclave or other pressure vessel; and rapidly discharged into the atmosphere or a region of reduced pressure to expand to form the foam beads. This process is well taught in U.S. Pat. Nos. 4,379,859 and 4,464,484.

Foamable and expanded beads can be made by a batch or by 00 an extrusion process. The batch process of making foamable beads is S.essentially the same as for manufacturing expandable polystyrene S 25 (EPS). The granules of a polymer blend, made either by melt blending or in-reactor blending as described above, are impregnated with a blowing agent in an aqueous suspension or in an anhydrous state in a pressure vessel at an elevated temperature and pressure. The granules are then either rapidly discharged into a region of reduced oressure o30 to expand to foam beads or cooled and discharged as unexpanded beads.

The unexpanded beads are then heated to expand with a proper means, with steam or with hot air. The extrusion method is essentially the same as the conventional foam extrusion process as described above up to the die orifice. The die has multiple holes. In order to make unfoamed beads, the foamable strands exiting the die orifice are immediately quenched in a cold water bath to prevent foaming and then pelletized. Or, the strands are converted to foam beads by cutting at the die face and then allowed to expand.

The foam beads may then be molded by any means known in the art, such as charging the foam beads to the mold, compressing the mold to compress the beads, and heating the beads such as with steam to effect coalescing and welding of the beads to form the article.

Optionally, the beads may be impregnazed! with air Or other blowing agent at an elevated pressure and temperature prior to charging to the mold. Further, the beads may be heated prior to charging. The foam beads may then be molded to blocks or shaped articles by a suitab' le molding method known in the art. (Som-e of the methods are taught in U.S. Pat. Nos. 3, 504, 063 an-d 3, 953, 553.) EXcellent teachings of the above processes and molding methods are seen in C.P. Park, sucra, p 191, pp. 197-198, and pp. 2297-229.

Slowing agents useful in m-aking the present foam structure include inorganic blowing agents, organic blow.-ing agents and che=mi;cal blowing agents. Suitable inorganic blIowina aoen ts icuecarbon dioxide, nitrogen, argon, water, air, nitrogen, and helium OrQan-ic blowing agents include aliphatic hydroca rbons havinc 1-6 carbon atoms, aliphatic alcohols having 1-3 carbon atoms, and fully and Partiail halogenated aliphatic hydrocarbons having 1-4 carbon atoms. A:.liohatic hydrocarbons include methane, ethane, Propane, n-butane, isobutane, npentane, isopentane, or neopentane. Aliphatic alcohols include methanol, ethanol, n-prooanol, and isopropanol. Fullv and oartial>, halogenated aliphatic hydrocarbons include fluorocarbons, chlorocarbons, and chlorofluorocarbons. xamoles of fluorocarbons include methyl fluoride, perfluoromethane, ethyl fluoride, 1, 1difluoroethane (HFC-152a) 1,1,1-trifluoroethane (HFC-143a) 1, 1,1, 2- 9***tetrafluoro-ethane (HFC-134a) 1,1, 2 2 -tetrafluoroethane (HFC 134), pentafluoroethane, difluoromethane, perfluoroethane, 2,2- 9 25 dif luoropropane, 1, ll-trif luoropropane, perf luoropropane, dichloropropane, difluoropropane, perfluorobutane, perfuorcyclbutne.Partially uhalogenated chlorocarbonsan chlorofluorocarbons for use in this invention include methyl chloride, methylene chloride, ethyl chloride, 1,l,l-trichloroethane, 1, 1dichloro-l-fluoroethane (HCEC-141b), l-chloro-l,l difluoroethane (HCFC-142b), ll-dichloro-2,2,2-trifluoroethane (HCFC-123) and Ichoo1,,,-ttalurehaeHFC 4. Fully halogenated chlorofluorocarbons include trichloromonofluoromethane (CFC-1l), 9 dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), 1, l,l-trifluoroethane, pentafluoroethane, dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane, and dichlorohexafluoropropane.

in. Chemical blowing agents include sodiumi bicarbonate, mixtures of sodium bicarbonate and citric acid, azodicarbonamide, azodiisobutyro-nitrile, benezenesulfonhydrazije, 4 4 -oxybenzene sulfonyl-semicarbazide, ptoluene sulfonyl semi-carbazide, barium azodicarboxylate,

N,N'-

diehlNN-iirstrptaaie and trihydrazino triazine.

Preferred blowing agents depend upon the process and product. For manufacturing a low-density foam by :he extursion process, a volatile organic blowing agent or carbon dioxide is preferred. Preferred volatile organic blowing agents include n-butane, isobutane, npenrane, isopentane, HFC-152a, and :mixtures thereof. For s ma.-.ufacturing a foamable bead produc:, isobutane, n-centane, ispentane and mixtures thereof are creferred.

The amount of blowing agents incorporated into the colvmer mel: material to make a foam-forming polymer gel is from 0.05 to preferably from 0.2 to 4.0, and most preferably from 0.5 to 3.0 gram moles per kilogram of polymer.

Various additives may be incorporated in :he present foam structure such as nucleating agents, inorganic fillers, pigmenzs, an:ioxidants, acid scavengers, ultraviolet absorbers, flame retardants, processing aids, extrusion aids.

In addition, a nucleating agent may be added in order to con:rol the size of foam cells. Preferred nucleating agents include inorganic substances such as calcium carbonate, talc, clay, titanium oxide, silica, barium sulfate, diatomaceous earth, mixtures of citric acid and sodium bicarbonate. The amount of nucleating agent emploved may range from 0.01 to 5 parts by weight per hundred parts by weight of a polymer resin.

The present foam structure is substantially noncrosslinked or uncross-linked. The alkenyl aromatic polymer material comprising the foam structure is substantially free of cross-linking.

S0 25 The foam structure contains no more than 5 percent gel per ASTM D- 2765-84 Method A. A slight degree of cross-linking, which occurs naturally without the use of cross-linking agents or radiation, is permissible.

The present foam structure has density of less than 450, 30 more preferably less than 200 and most preferably from 10 to kilograms per cubic meter. The foam has an average cell size of from 0.02 to 5.0, more preferably from 0.2 to 2.0, and most preferably 0.3 to 1.8 millimeters according to ASTM D3576.

The present foam structure may take any physical 35 configuration known in the art, such as extruded sheet, rod, plank, and profiles. The foam structure may also be formed by molding of foamable beads into any of the foregoing configurations or any other configuration.

The present foam structure may be closed-celled or opencelled. Preferably, the present foam contains 80 percent or more closed cells according to ASTM D2856-A.

Additives such as antioxidants hindered phenols such as, for example, IRGANOX® 1010, a registered trademark of CIBA- GEIGY), phosphites IRGAFOSD 168, a registered trademark of CIBA-GEIGY), uv stabilizers, cling additives polyisobutylene), antiblock additives, colorants, pigments, or fillers can also be included in the interpolymers employed in the blends of the present invention, to the extent that they do not interfere with the enhanced properties discovered by Applicants.

The additives are employed in functionally eauivalent amounts known to those skilled in the art. For example, the amount of antioxidant employed is that amount which prevencs the polmer or polymer blend from undergoing oxidation at the temperatures and environment employed during storage and ultimate use of the polyrmers.

Such amounts of antioxidants is usually in the range of from 0.01 to 1) 10, preferably from 0.05 to 5, more preferably from 0.1 to 2 =ercent by weight based upon the weight of the polymer or polymer blend.

Similarly, the amounts of any of the other enumerated additives are the functionally equivalent amounts such as the amount to render the polymer or polymer blend antiblocking, to produce the desired amount of filler loading to produce the desired result, to provide the desired color from the colorant or pigment. Such additives can suitably be employed in the range of from 0.05 to preferably from 0.1 to 35 more preferably from 0.2 to 20 percent by Sweight based upon the weight of the polymer or polymer blend.

S: 25 However, in the instance of fillers, they could be employed up to percent by weight based on the weight of the polymer or polymer blend.

The blends of the present invention can be utilized to produce a wide range of fabricated articles such as, for example a sheet or film resulting from calendaring, casting or blowing a blend, 30 an article resulting from injection, compression, extrusion or blow molding the blend and a fiber, foam or latex prepared from the blends.

The blends of the present invention can also be utilized in adhesive formulations.

The compositions of the present invention containing ignition resistant polystyrene modified with ethylene/styrene interpolymers can be used in injection molding applications to manufacture TV cabinets, computer monitors, or printer housings.

The following examples are illustrative of the invention.

TESTING

The properties of the polymers and blends were determined by the following test procedures Melt Flow Rate (MFR) was determined by ASTM n-1233 (1979), Condition E (190 0 C; 2.16 kg) Tensile Strenoth was determined by ASTM D-882-91, Procedure

A

except: Five replications of the test were made for each polymer s blend tested. Grip separation .as always 1 inch (2.54 cm) Grio separation speed was always 5 /min.

Modulus was determined by ASTM :-382-91, Procedure A exceot: Five replications of the test were made for each polymer blend tested.

Grip separation was always 1 inch (2.54 cm) Grip separation speed was always 5 mm/min.

Elongation was determined by D-882-91, roceduare A exceot: Five replications of the test :ere maze for each polymer blend tested.

Grip separation was always 1 inch (2.5 cm) Grip separation sceed was always 5 mm/min.

s Touhness was determined by AST?:! D-882-91, Procedure A2.1 except: Five replications of the test were made for each polymer blend tested. Grip separation was al:..ays 1 inch (2.54 cm). Grip separation speed was always 5 .m/min.

Preparation of Ethvlene/Stvrene Interc-ivmers A G 0 A two liter scirred reactor was charged with about 500 ml of mixed alkane solvent (ISOPART" E, a registered trademark of and available from Exxon Chemicals Inc.) and ca. 500 ml of styrene comonomer. Hydrogen was then added by differential pressure expansion from a 75 ml shot tank. The reactor was heated to the desired run 2s temperature and the reactor was saturated with ethylene at the desired pressure. The (tertamethylcyclcpentadienyl) (tert-butylamido)dimetbylsilane titanium dimethyl catalyst and tris(pentafluorophenyl)borane cocatalyst were mixed in a dry box by mixing the catalyst and cocatalyst in ISOPART" E in an inert atmosphere glove box. The o. 30 resulting solution was transferred to a catalyst addition tank and injected into the reactor. The polymerization was allowed to proceed with ethylene on demand. Subsequent additions of catalyst solution prepared in the same manner were optic-ally added during the run.

S* After the run time the polymer solution was removed from the reactor and mixed with 100 mg of IRGANOX

T

101C (a registered trademark of CIBA-GEIGY) in 10 ml of toluene. The polymers were precipitated with propanol and the volatiles were removed from the polymers in a reduced pressure vacuum oven at 120 0 C for ca. 20 hr.

The monomer amounts and polymerization conditions are provided in Table 1A. The yield and polymer properties are provided in Table IB.

Table 1A polymer parTM

E

(g) rene Hydrogen (delta) Ethylene JRun Time

F

T

o-i I-c km n )j A 358 455 0 0 200 1, 379 80 B 361 454 13 90 250 1, 724 2-0 C 6 5 1 76 150 1, 034 20 D 361 461 j11 76 100 689- 2-0 E 365 461j 0 0 -100 689 -3-0 S420__ 381 0 o 0 50 345- 3-0 ~un Catemp alyst OC) (pmol) 20 0 T0 80 6 To0 9 30 12 T0 O 0 2 0 4 12 83 U 50 345 30

H

i 360 768 16 461 1 1! 103 69 50 300 345 2,0 68 30 I20

I

lB Melt Styrene Content E/S Amorphous Inter- Yield Flow in Interpolymer Inter- Polypolymer Rate _____polymer styrene dg/min mol wt. wt. wt. A 72.7 j0.195 20.1 48. 3 96 4 B 69.9 0.40 7. 4 22. 9 99.670.

C 57.7 0. 74 17V.8 44 .6 9-8.1 1. 9 D 48.4 3.62 24 .9 55.2 9_7. 8 2.2 E 59.3 1.52 26.5 57.3 97.4 26 F 85.6 13.1 34 .3 66.0 94.8 5 2 G 114.7 1.07 41.0 721 98.6 1.4 H 96 0.92 47 .3 7-6. 9 -4 9. 8 5.2 I-7 67 14 _r 8.4 25.4 98 2 EXAMPLE 1 A. thvlene/stvrene interoolvmer The ethylene/styrene interpolvrner dcsignated as H in Tables 1A 1B was employed in this example.

B. Prearation of blend of /S interpolvmer arid polystyrene.

The polymer material was pelletized and blended with a general purpose polystyrene (PS) having a weight average molecular -21weight of about 200,000 and a polydispersity of 2.5. The level of the ES copolymer in the blend was varied from 0 to 40 The tests were as follows. A total of 40 grams of granular resin mixture was melt blended by using a Haake Rheocord Model 90 mixer for 15 minutes at 180 OC and 30 rpm rotor speed under a nitrogen blanket. The blends were pressed to thin sheets of approximately 0.9 mm thickness on a hot press maintained at 177 oC. The sheets were cut into 1/2" (1.27 cm)wide strips by using a Thwing-Albert Model LDC-50 cutter. Tensile properties of the specimens were determined by using an Instron 1123 tensile tester at 5 mm/min cross-head speed and 1" (2.54 cm) jaw scan.

Five specimens were run for each blend and the average of the five data points was reported as the representative property for the blend.

The test results are shown in Table 2. At an ES level lower than 40%, the blend does not show a measurable improvement in mechanical toughness. At the blend level of 40%, these properties of the blend become dramatically improved. A 60/40: PS/ES blend was elongatable to over 70% of its original length and has a relatively high modulus. A transmission electron microscope micrograph shows that the blend has a co-continuous structure.

Table 2 Test ES Tensile Elongatio Toughness Modulus No. Level Strength n (MPa) Break (MJ/cu.m) (MPa) (3) 1.1* 0 39.2 5.4 1.2 924 1.2 10 28.1 4.4 0.6 827 1.3 20 24.5 3.3 0.5 965 1.4 30 35.7 5.2 1.0 972 40 27.6 70.2 18.5 876 Not an example of the present invention ethylene/styrene interpolymer H mixed in as a percentage of the total polymer blend.

Tensile strength at break in megapascals.

Elongation at break in a percentage of the initial length.

Toughness determined by the area under the tensile curve in megajoules per cubic meter.

2% secant modulus in megapascals.

EXAMPLE 2 In this example, the tests of Example 1 were repeated with six different ES interpolymers with varying ethylene/styrene ratios and melt indices. The ES interpolymers were prepared as shown in Table 1A employing different ethylene/styrene ratios. All materials contained a small amount (less than of amorphous polystyrene.

Forty parts of each ES interpolymer was blended with sixty parts of polystyrene as employed in Example 1. As shown in Table 3, all the ES -22-

T

interpolymer materials led to toughened polyblends. In general, an interpolymer having a higher level of styrene performs better. The interpolymer that was used in Test No. 2.5 was an exception. The performance of the resin falls off from the general trend. It is s believed that the high melt index (or low viscosity) of the material is responsible for the relatively poor performance.

Table 3 Test No.

E/S Interpolymer Type Sty- MFR rene dg/Min S (2) (1) Tensile Properties of polyblends Tens- Elong- Tough- Modile ation ness ulus Str- Break (MJ/m 3 (MPa) ength (6) (4) Break (MPa) (3) 2.1 B 7.4 0.40 19.9 21.4 3.5 356 2.2 I 8.4 0.14 24.3 13.8 2.6 483 2.3 C 17.8 0.74 15.6 57.4 9.4 315 2.4 E 26.5 1.52 12.1 87.6 11.2 303 F 34.3 13.1 14.5 30.1 4.2 381 2.6 G 41.0 1.07 25.1 268.0 61.1 430 Styrene content of ES interpolymer in mole percent.

Melt index of ES interpolymer determined per ASTM 1238 at 190 0 C/2.16 kg.

Tensile strength at break in megapascals.

Elongation at break in a percentage of the initial length.

Toughness determined by the area under the tensile curve in megajoules per cubic meter.

2% secant modulus in megapascals.

(6) Example 3 In this example, Test 2.6 was repeated with substitution of the polystyrene component with another polystyrene having a weight average molecular weight of 300,000 and polydispersity of 2.4. As shown in Table 4, this resin blend has the desired toughness and relatively high modulus.

Table 4 Test ES Tensile Elongati Toughness Modulus No. Level Strengt on h Break (MJ/m 3 (MPa) (MPa) (3) 3.1 40 17.5 207.0 44.4 382 ethylene/styrene interpolymer G (41.0 mole flow rate) mixed in as a percentage of the Tensile strength at break in megapascals.

Elongation at break in a percentage of the Toughness determined by the area under the megajoules per cubic meter.

21 secant modulus in megapascals.

EXAMPLE 4 i styrene, 1.07 melt total polymer.

initial length.

tensile curve in r In this example, an ES interpolymer (Interpolymer A in Tables 1A and IB) having 20.1 mole 3 (43.3 weight percent) styrene was blended, at 10 and 20 percenc level, with a polystyrene resin as used in Example 1. The ES interpoimer contains approximately 4% amorohous polystyrene in the total po1lyer. As shown in Table 5, an ES interpolymer level uc to 20 in the blends was insufficient for achieving a tough blend.

Table Test ES Tensile Elongaci Toucgness Modulus No. Leve Strength on 1 Break (CMJ/cu.m) (MPa) 2) (3) 4.1 10 7 4. 0.6 869 4.2 20 31.6 5.6 800 4.3 20 36.2 6.5 i.3 855 ethylene/s:yrene interpolymer (20.1 mole styrene, 0.2 melt flow rate) mixed in as a percentage of the total polymer.

Tensile strength at break in megapascals.

Elongation at break in a percentage of the initial length.

is Toughness determined by the area under the tensile curve in megajoules per cubic meter.

25 secant modulus in megapascals.

COMPARATIVE EXPERIMENT A (Not an example of the present invention) In this comparative experiment, the polystyrene in Example 20 1 was blended with a commercial styrene-butadiene-styrene tri-block interpolymer (SBS) (VECTOR" 6241-D a registered trademark of and available from Dexco Polymers). As shown in Table 6, a 60/40: PS/SBS blend has a good elongation and desired toughness. However, the blend lacks stiffness (as indicated by the lower modulus values) compared to the PS/ES blends. A high modulus was desired for most applications of the polymer blends.

Table 6 Test SBS Tensile Elongation Toughne Modulus No. Level Strengt Break ss (Mpa) h MJ/m 3 (MPa) (4) 5.1* 40 22.5 244.0 44.0 272 Not an example of the present invention.

VECTORTM 6241-D brand SBS interpolymer (a registered trademark of and available from Dexco Polymers) mixed in as a percentage of the total polymer Tensile strength at break in megapascals Elongation at break in a percentage of the initial length 3s Toughness determined by the area under the tensile curve in megajoules per cubic meter 2% secant modulus in megapascals EXAMPLE Preparation of ES Copolvmer An ethylene-styrene (ES) substantially random copolymer identified as H in tables 1A B was employed in this example. This s ES copolymer contains 76.9 weight (47.3 mol) percent styrene moiety and has a melt index of 0.92 as determined by ASTM D-1238 at 190°C/2.16 kg.

Expandabilitv Testing The blends used in this example were those prepared in Example 1. The blends were compression-molded in a mold of approximately 1" (25.4 mm) in diameter and 0.1" (2.5 mm) in depth on a hot press that was maintained at approximately 1800C.

The disc-shaped specimens, three per formulation, were loaded in a pressure vessel on wire mesh trays lined with Teflon" is fluoropolymer. The trays were suspended by a support so as not to be in a direct contact with the liquid blowing agent that would be subsequently charged in and settled at the bottom of the vessel.

Approximately 2.8 grams of isopentane was charged into the vessel.

With its lid closed and the air purged out with nitrogen, the vessel 20 was heated in an oil bath maintained at 60 0 C for about 6 days. The vessel was cooled down and the specimens were removed. The thickness Sof the specimens after blowing agent impregnation ranges from 70 mils (1.8 mm) to 127 mils (3.2 mm). Shortly after, one specimen per each formulation was cut into halves and the cut pieces were exposed to 25 atmospheric steam for five minutes. As shown in Table 7, PS/ES blends absorb isopentane in excess of 10 parts per one hundred parts of polymer (pph) and expanded to reasonably low densities. The 90/10:PS/ES blend achieves the lowest density of 44 kg/m 3 In contrast, the pure polystyrene specimen absorbs less 3 0 than 3 pph isopentane and expands to 94 kg/m 3 density. The relatively high density foam which results with the 60/40:PS/ES blend was probably due to an excessively long exposure to steam. The blend foam showed a sign of shrinkage when taken out of the steam pot.

jy r r r Table 7 Expandability of PS/ES Blends Impregnated with Isopentane Test Form- Thick- iCs Foam Density No. ulation ness Level (4) (mm) (pph) (ib/ft 3 (Kc/m 3 5.1* PS I .38 3.0 5.9 5.2 PS/ES 2.1 14.3 2.7 90/10 5.3 PS/ES 2.8 13.8 3.8 61 80/20 5.4 PS/ES 3.2 11.6 4.8 77 70/30 PS/ES 3.0 10.3 8.3 133 60/40 s Not an example of the present invention.

PS general purpose polystyrene having 200,000 weight averae molecular weight; ES ethylene-styrene copolymer made with 76.9 wt. styrene and having 0.92 M.I.

1o Thickness of the specimen in millimeters.

3) Amount of isopentane contained in the specimen immediately after impregnation in parts per 100 parts of polymer.

Density of foam body achieved by expansion of fresh specimens in atmospheric steam for 5 minutes in both pounds per cubic root and kilogram per cubic meter.

Blowing Aaent Retention The blowing agent retention capability of the specimens 20 impregnated with isopentane above was examined by periodically weighing the specimens during aging at an ambient temperature Sof 23C. The monitoring continued for 8 months and the data were summarized in Table 10. Since the fractional loss of blowing agent was inversely proportional to the square of the thickness, the data need to be compared in terms of corrected aging time; corrected for 2 mm-thick specimens. For ease of comparison, the data were interpolated to give blowing agent retention at a discrete aging time as presented in Table 8.

The data indicate that PS/ES blends retain isopentane well, 30 much better that a pure polystyrene. PS/ES blends retain over 65% of the initial blowing agent for 3 months, while the polystyrene specimen losses one half of its blowing agent within a week.

Table 8 Retention of Isopentane by PS/ES Blends at 23 0

C.

Test. Formu- Isopentane Retention After Aging at 23°C No. lation for the Period (days) (2) 0 7 14 30 60 90 120 2.1* PS 2.8 1.4 1.2 0.9 0.5 0.4 0.3 2.2 PS/ES 14.9 12.5 11.8 10.9 9.9 9.4 90/10 2.3 PS/ES 12.9 11.7 11.2 10.6 9.8 9.4 9.1 80/20 2.4 PS/ES 10.3 9.5 9.1 8.6 8.0 7.7 7.4 70/30_ PS/ES 10.0 8.7 8.3 7.6 7.0 6.6 6.4 60/40 *Not an example of this invention.

PS general purpose polystyrene having 200,000 weight average molecular weight; ES ethylene/styrene copolymer made with 76.9 wt. percent.

styrene and having 0.92 M.I.

Retention of isopentane by 2 mm-thick specimens after aging 1 0 for the specified period at 23°C in parts per one hundred parts of polymer.

The ethylene-styrene copolymer prepared above was compression-molded to a disc by the same procedure as above. The disc specimen was impregnated with HCFC-11lb at 60 0 C for 8 days per the above procedure. Retention of the blowing agent by the specimen was monitored by periodically weighing during aging at an ambient temperature of 23 0 C for 6 days. The specimen thickness was about 3 mm. As shown in Table 9, the specimen retains HCFC-141b blowing agent 20 reasonably well.

S• Table 9 Retention of R-14lb by an Ethylene/.Styrene Copolymer Elapsed Time (days) 0 1 3 4 6 o* R-141b Retention 3.2 3.0 2.9 2.9 2.9 23°C (pph) EXAMPLES 6 13 Interpolymer preparations and characteristics: Preparation of Interpolymers J, K, L Polymer was prepared in a 400 gallon agitated semi- 30 continuous batch reactor. The reaction mixture consisted of approximately 250 gallons a solvent comprising a mixture of cyclohexane (85wt%) isopentane (15wt%), and styrene. Prior to addition, solvent, styrene and ethylene were purified to remove water and oxygen. The inhibitor in the styrene was also removed. Inerts were removed by purging the vessel with ethylene. The vessel was then -27- .p S r pressure controlled to a set point with ethylene. Hydrogen was added to control molecular weight. Temperature in the vessel was controlled to set-point by varying the jacket water temperature on the vessel.

Prior to polymerization, the vessel was heated to the desired run s temperature and the catalyst components: Titanium: dimethylethyl)dimechyl(1-(1,2,3, ,5-eta)-2,3,4,5-tetrameth-.- 2,4cyclopentadien-l-yl)silanaminato)) (2-)N)-dimethyl, CAS# 135072-62-7, Tris(pentafluorophenyl)boron, CASK 001109-15-5, Nodified methylalumin-oxane Type 3A, CAS4 146905-79-5, were flow cotroilled, on o0 a mole ratio basis of 1/3/5 respectively, combined and added to the vessel. After starting, the colmierization w:as allowed to croceed with ethylene supplied to the reactor as required to maintain vessel pressure. In some cases, hydrogen was added to the headspace of the reactor to maintain a mole ratio with respect to the ethvlene concentration. At the end of the run, the catalyst flow was stopped, ethylene was removed from the reactor, about 1000 ppm of Irganox:\ 1010 (a registered trademark of CIBA-GEIGY) anti-oxidant was then added to the solution and the polymer was isolated from the solution. Catalyst efficiency was generally greater than 100,000 kg. polymer per ka. Ti.

The resulting polymers were isolated from solution by either stripping with steam in a vessel or by use of a devolatilizing extruder. In the ,o case of the steam stripped material, additional processing was required in extruder-like equipment to reduce residual moisture and any unreacted styrene.

SInter- Solvent Styrene Pressure Temp. Total Run Polymer polymer loaded loaded Hz Time in Added Solution ib kg ib kg Psi kPa 0 C Grams Hours Wt. g 252 114 1320 599 40 276 60 0 6.5 18.0 839 381 661 300 105 724 60 53.1 4.3 11.6 1196 542 225 102 70 483 60 7.5 6.1 7.2 r* 25 Interpo Melt Total Talc Isolation lymer Index Wt% Level Method 12 Styrene Wt in Polymer* 1.83 81.6 <2.5 Steam -Strip 2.6 45.5 0 Extruder S(L) 0.03 29.8 0 Extruder Total weight percent styrene measured via Fourier Transform Infrared (FTIR) technique.

The interpolymer and vinyl aromatic polymer characteristics were given in table 10. The unblended polymers provide the comparative experiments.

0. r r

C

r Table Interpolymer and vinylidene aromatic polymer blend components qxl0-(0.1 1.01 1.05 16.6 4.48 rad/sec), Poise q(100/0.1) 0.14 0.15 0.16 1 0.018 Tan 6 (0.1 9.98 4.2 2.37 2.59 rad/sec) Not an example of the present invention 1 ratio of q(0.1) 2 StyronTM 685D is a general purpose polystyrene commercially available from and a registered trademark of The Dow Chemical Company, Midland, MI.

3 Cannot be measured.

4 Measured by NMR technique.

Test parts and characterization data for the interpolymers and their blends were generated according to the following procedures: Compression Molding: Samples were melted at 190°C for 3 minutes and compression molded at 190°C under 20,000 lb. of pressure for another 2 minutes. Subsequently, the molten materials were quenched in a press equilibrated at room temperature.

Density: The density of the samples was measured according to ASTM-D792.

Differential Scanning Calorimetry (DSC): A Dupont DSC-2920 was used to measure the thermal transition temperatures and heat of transition for the interpolymers. In order to eliminate previous thermal history, samples were first heated to 200°C. Heating and cooling curves were recorded at 10°C/min. Melting (from second heat) and crystallization temperatures were recorded from the peak temperatures of the endotherm and exotherm, respectively.

Melt Shear Rheology: Oscillatory shear rheology measurements were performed with a Rheometrics RMS-800 rheometer Rheological properties were monitored at an isothermal set temperature of 190oC in a frequency sweep mode. In tabulated data, q is the viscosity and T(100/0.1) is the viscosity ratio of values recorded at 100/0.1 rad/sec frequencies.

Mechanical Testing: Shore A hardness was measured at 23 0 C following ASTM-D240.

20 Flexural modulus was evaluated according to ASTM-D790.

Tensile properties of the compression molded samples were measured using an Instron 1145 tensile machine equipped with an extensiometer. ASTM-D638 samples were tested at a strain rate of min The average of four tensile measurements is given. The yield 25 stress and yield strain were recorded at the inflection point in the stress/strain curve. The Energy at break is the area under the stress/strain curve.

.Tensile Stress Relaxation: Uniaxial tensile stress relaxation was evaluated using an Instron 1145 tensile machine. Compression 30 molded film 20 mil, 0.0508 cm., thick) with a 1" (2.54 cm) gauge length was deformed to a strain level of 50% at a strain rate of min 2 The force required to maintain 50% elongation was monitored for 10 min. The magnitude of the stress relaxation is defined as (fiff/fi) where fi is the initial force and ff is the final force.

Thermomechanical Analysis (TMA) Data were generated using a Perkin Elmer TMA 7 series instrument. Probe penetration was measured to 1 mm depth on 2 mm thick compression molded parts using a heating rate of 5°C/min and a load of I Newton.

Examples 6-8 Blend Preparation: Three blend compositions, examples 6, 7 and 8, were prepared from interpolymer and vinyl aromatic polymer above in weight ratios of of 90/10, 70/30 and 50/50 with a Haake mixer equipped with a Rheomix 3000 bowl. The blend components were first dry blended and then fed into the mixer equilibrated at 190 0 C. Feeding and temperature equilibration took about 3 to minutes. The molten material was mixed at 190°C and 40 rpm for minutes.

The characterization data for these blends and the blend components is given in table 11.

Table 11 Blend polymer or Example No.

6 7 8 Blend Composition, 100/0 0/100 90/10 70/30 50/50 wt. ratio Mechanical Properties Shore A hardness 98 98 96 97 98 Tensile Modulus, MPa 703.3 1860.3 654.3 1202.5 1696.9 Flexural Modulus, MPa 620.6 3135.8 N.D. N.D** Yield Stress, MPa 7.5 39.5 6.4 9.9 24.5 Strain Break 248.3 1.6 230.5 184.3 12.7 Stress Break, MPa 17 38.8 19.4 17.4 26 Energy Break, N-m 98.2 1.1 114.6 97.4 11.9 Stress Relaxation 93.5 CBM1 90.7 85.7 CBM (50%/10min) TMA OC 66 118 74 84 103 Melt Rheology nxl0o (0.1 rad/sec), 1.01 4.48 1.2 1.37 2.36 Poise T (100/0.1) 0.14 0.018 0.12 0.088 0.049 Tan 6 (0.1 rad/sec) 9.98 2.59 9.09 4.66 2.7 Not an example of the present invention.

Not determined.

1 cannot be measured.

2 Temperature to 1 mm probe depth.

Olefin-based polymers generally show poor compatibility with vinyl aromatic polymers, and hence to achieve good performance characteristics there is usually a need to provide some form of compatibilization technology. This poor compatibility is generally associated with low toughness.

Table 11, however, shows that the blend composition examples 6, 7 and 8 all have good mechanical integrity, and have not lost any strength performance as evidenced by the stress, strain and energy at break. The 50/50 composition, although showing a lower toughness than the other two compositions, is nevertheless a factor of higher than the unmodified vinyl aromatic polymer.

-32- Further, the blends retain an unexpected level of stress relaxation compared to what may be expected from the component polymers. The high temperature performance of the compositions as shown by probe penetration to 1 mm depth in a thermomechanical s analysis (TMA) test was greatly improved in the blends. Example 8, containing 50 wt. percent of polystyrene shows resistance to penetration approaching that of the polystyrene.

The melt rheology data for the three blend examples 6, 7 and 8 shows that the low shear performance (0.1 rad/sec) can be Io manipulated by blending, with the blends having low viscosities. Low tan 6 values were found at low shear rates for examples 7 and 8. This translates to higher melt elasticity and improved part forming characteristics under certain melt processing operations, compared to unmodified interpolymers.

Examples 9-11 Blend Preparation: Three blend compositions, examples 9, and 11, were prepared from interpolymer and vinyl aromatic polymer above in weight ratios of of 85/15, 70/30 and 20 50/50 with a Haake mixer equipped with a Rheomix 3000 bowl. The blend components were first dry blended and then fed into the mixer equilibrated at 190 0 C. Feeding and temperature equilibration takes about 3 to 5 minutes. The molten material was mixed at 190°C and rpm for 10 minutes.

25 The characterization data for these blends and the blend components is given in table 12.

Table 12 Blend Polymer or Example No.

9 10 11 Blend Composition, 100/0 0/100 85/15 70/30 50/50 wt. ratio Mechanical Properties Shore A 75 98 76 89 97 Tensile Modulus, MPa 6.5 1860.3 13.8 68.9 661.9 Flexural Modulus, MPa 68.8 3135.8 52.4 111.7 688.8 Yield Stress, MPa 1.3 39.5 2 4.3 9.4 Strain Break 475.3 1.6 481.3 459.4 4.4 Stress Break, MPa 22.6 38.8 20.3 10.3 Energy Break, N-m 102.2 1.1 89.1 74.4 1.2 Stress Relaxation 38 CBM' 51.2 66.1 CBM (50%/10min) Melt Rheology ixl0-'(0.1 rad/sec), 1.05 4.48 1.07 1.26 2.1 Poise r (100/0.1) 0.15 0.018 0.12 0.093 0.057 Tan 6 (0.1 rad/sec) 4.2 2.59 3.43 3.49 2.91 Not an example of the present invention.

1 Cannot be measured.

s 2 Not measured.

Table 12 shows that the blend composition examples 9, and 11 all have good mechanical integrity, and have not lost any strength performance as evidenced by the stress, strain and energy at 10 break compared to the individual component polymers. The 50/50 composition, although showing a lower toughness than the other two compositions, was nevertheless higher than the unmodified vinyl aromatic polymer.

Further, blends 9 and 10 show high levels of stress relaxation compared to the component interpolymer.

The melt rheology data for the three blend examples 9, and 11 shows that the low shear performance (0.1 rad/sec) can be manipulated by blending, with the blends having low viscosities.

Examples 12 13 0 Blend Preparation: Two blend compositions, examples 12 and 13, were prepared from interpolymer and vinyl aromatic polymer (D) above in weight ratios of of 75/25 and 50/50 with a Haake mixer equipped with a Rheomix 3000 bowl. The blend components were first dry blended and then fed into the mixer equilibrated at 190 0

C.

Feeding and temperature equilibration took about 3 to 5 minutes. The molten material was mixed at 190 0 C and 40 rpm for 10 minutes.

The characterization data for these blends and the blend components is given in table 13.

-34- .p r- Table 13 Blend polymer or Example No.

12 13 Blend Composition, 100/0 0/100 75/25 50/50 wt. ratio Mechanical Properties Shore A 98 95 97 Tensile Modulus, 20 1860.3 194.4 1313.5 Flexural Modulus, !Ma 62.1 3135.3 N.D. i.D.

Yield Stress, Ha 2.4 39.5 9.8 16.6 Strain Break 377.5 1.6 199.8 20.6 Stress Break, M?a 34.3 T 38.8 14 .2 Energy Break, .m 145.5 92.6 6.4 Stress Relaxation 3 0.2 NiD** 46 (50%,/10min) Melt Rheology qxlO-'(0.1 rad/sec), I 16.6 4.48 21.1 J Poise r (100/0.1) 0.16- 0.018 0.012 0.023 Tan 6 (0.1 rad/sec) 2.37 2.59 0.64 1.-32 Not an example of the present invention.

not determined.

The e.xamles 12 13 show the excellent compa.tibiiity with high olefin-containing interpolyers, via the mechanical property data. The blends show a hich yield stress, and good strain at break values. Further, blend 12 retains an unexpected level of stress 10 relaxation compared to interpolymer The blends both show low tan 5 values; this translates to higher melt elasticity and improved part forming characteristics under certain melt processing operations compared to either blend component.

EXAMPLE 14 15 A. Preparation of Ethylene/Styrene Copolymers Ethylene/styrene copolymers were made using (tert-butylamido)dimethyl(tetramethyl-eta5-cyclopentadienyl)silane dimethyltitanium (IV) catalyst and tris (pentafluorophenyl) borane cocatalyst according to the following procedure. A two liter stirred reactor was 20 charged with about 360 g of mixed alkane solvent (Isopar-E- from and Sregistered trademark of Exxon Chemicals Inc.) and about 460 g of styrene comonomer. Hydrogen was added to the reactor by differential pressure expansion from a 75 mL addition tank. The reactor was heated to 80 0 C and the reactor was saturated with ethylene at the desired pressure. Catalyst and cocatalyst were mixed in a dry box by pipeting the desired amount of 0.005 M solution of cocatalyst in toluene into a solution of a catalyst in toluene. The resulting solution was transferred to a catalyst addition tank and injected into the reactor.

The polymerization was allowed to proceed with ethylene on demand.

Additi anal charges of aalyst and cocatalyst were added to the reactor periodically. After 20 minutes the polymer solution Was removed from the reactor and quenched with isopropyl alcoh~ol.

A

nlndered phenol antioxidant (1rganox, 1010 available from and a rec,:istered trademark of Ciba Geigy Coro.) 100 mg, was added to the coivrmers. Volatiles were removed from the polymers i.n a reducedpressure vacuum oven at 135'C for ab-out 20 hrs. The ethylene and de-ita Hi pressures employed in the preparation of the ethyliene/stvrene cocolv-,er and the melt inde:: an~d styr-ene content in thIe resultant 0 -col,,-er are provided in the follow.ing table 14.

Table 14 S. .5

S.

.5.5.5

S

Table 14 (contd.) Inter- I, Styrene polymer Content Motle T wt.% E -1 0.37 17.3 43 .7 S -2 j 22 13.9 7. 5 No t E/S -3 0.10 0.4 0. Detected 1.8 B. Preparation of Injection Molded Samoles for Testinq The components of Table 15 were compounded between 190'C and 210'C on a Baker Perkins MPC corotating 30 mm. twin screw V30 mixer followed by a vented 38 mm single screw extruder. The polymer melt was passed through a two hole die and the polymer strands were cooled 20 in a water bath and cut into pellets.

The resins were injected molded on a Demag D100-75 injection molder equipped with a 31 mm diameter barrel and a mold containing cavities for the specimens used in property testing.

Table Component COMPONENT Wt. Percent DesignationI U Polymer Modifier R HIPS XZ-95198.00' 79. 9 S TBBA 2 8.3 S SayteX T m 'I 80103 1 T Antimony oxide 3.3 1A high impact Polystyrene available from The Dow Che mical Company having the following properties: melt flow rate 3 g/10 min. r c, 200C/5 kg and an Izod impact strength of 2.2 ft-lb/inch (12 kg- Cm/cm).

2 Tetrabromo bisphenol

A.

3 A brominazed flame retardant commercially available from and a registered trademark of Albemarle.

The test results of the molded ignition resistant polystyrene (IRS) blends are provided in the following table 16.

Table 16 1102a* E/S-1 E/S-2 E/S-3 Kraton Instrumented l102a Dart Impact Strength, in-lb 50 65 40 0 kg-cm 58 75 46 58 Melt Flow Rate a a a.

a.

a a.

min 200°C/5 kg Vicat Softening Temp., °F

°C

Tensile Modulus, psi MPa Tensile Yield psi MPa Tensile Elong. at rupture, Gardner Impact, in.-lb.

kg-cm UL-94 Flammability Rating at 2.0 mm 202 (94.4) 313,000 2,158 3,980 27 80 157 181 V-2 b 203 (95) 287, 000 1,978 3,980 27 60 137 158 V-2 b 202 (94.4) 302,000 2,082 3,970 27 80 203 282,000 1, 944 3,830 26 104 V-2 b 84

V-

2 b Not an example of the present invention.

a A 70/30 styrene-butadiene tri-block rubber (SBS copolymer) a registered trademark of and from Shell. KratonT 1102 has the following properties: melt flow rate 12 g/10 min 200 0 C/5 kg.

b This numerical rating is not intended to reflect hazards presented by this or any other material under actual fire conditions.

The total energy absorbed in the Gardner impact test ranged from 73 to 157 in-lb (84 to 181 kg-cm) for the E/S copolymers as compared to 90 in-lb (104 kg-cm) for the SBS copolymer. This range of values indicates that the impact strength of a flame resistant HIPS can be improved by the addition of ES interpolymers; that the impact strength of the ignition resistant polystyrene (IRPS) is affected by the composition of the E/S copolymer; and (3) that the impact strength of the IRPS containing interpolymers can be comparable or greater than that containing typical SBS, the impact modifiers which are currently used commercially.

oee *e

Claims (13)

1. A blend of polymeric materials comprising from about 1 to about 99 weight percent of at least one interpolymer containing from about 1 to about 65 mole percent of S(a) at least one vinylidene aromatic monomer, or E at least one hindered aliphatic vinylidene monomer, or a combination of at least one vinylidene aromatic monomer and at least one hindered aliphatic vinylidene monomer, and i2) from about 35 to about 99 mole percent of at least one ;c aliphatic a-olefin having from 2 to about 20 carbon atoms; and S from about 1 to about 99 weight percent of 1? at least one homopolymer of a vinylidene aromatic monomer, or 13 at least one interpolymer of one or more vinylidene aromatic 14 monomers and/or one or more hindered aliphatic vinylidene fs monomers, or 16 at least one of or which additionally contains an 17 impact modifier, or e1 a combination of any two or more of or

2. A blend of Claim 1 wherein component is employed 2 in an amount of from about 35 to about 99 weight percent, based 3 on the combined weight of components and and component 4 (B)is employed in an amount of from about 65 to about 1 weight 5 percent, based on the combined weight of components and

3. A blend of Claim 1 wherein component is employed in an amount of from about 40 to about 97 weight percent, based 3 on the combined weight of components and and component 4 (B)is employed in an amount of from about 60 to about 3 weight percent, based on the combined weight of components and 1 4. A blend of Claim 1 wherein component is employed in an amount of from about 40 to about 95 weight percent, based 3 on the combined weight of components and and component S(B)is employed in an amount of from about 60 to about 5 weight s percent, based on the combined weight of components and (B) -39- o 1

5. A blend of any preceding claim wherein 2 component (A2) contains from 2 to 12 carbon atoms; 3 (ii) the monovinylidene aromatic monomer(s) of component is 4 represented by the following general formula: Ar I Ri C CH 2 6 wherein R' is selected from the group of radicals consisting of 7 hydrogen and alkyl radicals containing three carbons or less, and 8 Ar is a phenyl group or a phenyl group substituted with from 1 to 9 5 substituents selected from the group consisting of halo, CI_ alkyl, and Ci-4-haloalkyl. 1

6. A blend of any preceding claim wherein the 2 interpolymerizable monomer of component is selected from the group 3 consisting of a-methyl styrene, N-phenyl maleimide, N-alkyl maleimide, 4 acrylamide, acrylonitrile, methacryionitrile, maleic anhydride, s acrylic acid, Ci-4 alkyl acrylates or C4., alkyl methacrylates. 1

7. A blend of any preceding claim wherein component (B) 2 is polystyrene or polystyrene containing an impact modifier.

8. A blend of any preceding claim wherein component (Ala) 2 is styrene and component (A2) is ethylene or a combination of ethylene 3 and at least one of propylene, 4-methyl pentene, butene-1, hexene-1 or 4 octene-1. 1

9. A blend of any preceding claim wherein component (Ala) 2 is styrene; component (A2) is ethylene or a combination of ethylene o. 3 and at least one of propylene, 4-methyl pentene, butene-1, hexene-1 or 4 octene-1; and component is polystyrene or polystyrene containing an impact modifier. 10 A blend of any preceding claim wherein component (A) 2 is produced by polymerization in the presence of a metallocene or 3 constrained geometry catalyst and a co-catalyst. 1

11. An adhesive composition containing a blend of any of 2 claims 1-10. 1

12. A sheet or film resulting from calendaring, casting 2 or blowing a blend of any of claims 1-10. 1

13. An article resulting from injection, compression, 2 extrusion or blow molding a blend of any of claims 1-10. r, (I

14. A fiber, foam or latex prepared from a blend of any 2 of claims 1-10. A foamable composition comprising at least one blowing agent; and S (II) at least one interpolymer or blend of interpolymers comprising 4 from about 1 to 100 percent by weight of at least one interpolymer comprising 6 from about 1 to about 65 mole percent of at least 7 one vinylidene aromatic monomer, or at least one 8 hindered aliphatic vinylidene monomer, or a 9 combination of at least one vinylidene aromatic monomer and at least one hindered aliphatic vinylidene 11 monomer, and 12 from about 35 to about 99 mole percent of at least one 13 aliphatic a-olefin having from 2 to about 20 carbon 14 atoms; and 15 from 0 to about 99 percent by weight of at least one 16 homopolymer of a vinylidene aromatic monomer and/or a 17 hindered aliphatic vinylidene monomer, or at least one S i 8 interpolymer of one or more vinylidene aromatic monomers 19 and/or one or more hindered aliphatic vinylidene monomers 20 and optionally one or more polymerizable ethylenically 21 unsaturated monomers other than a vinylidene aromatic 22 monomer or hindered aliphatic vinylidene monomer. 1

16. A foam resulting from subjecting the foamable 2 composition of Claim 15 to foaming conditions. Dated 20 December, 2001 The Dow Chemical Company 0 Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON -41-