DE2839357A1 - COMPOSITION OF A POLYSTYRENE RESIN AND A PRE-MIXED POLYMER SYSTEM CONTAINING A POLYOLEFIN AND A SELECTIVELY HYDROGENATED BLOCK COPOLYMER OF A VINYLAROMATIC COMPOUND AND AN OLEFINIC ELASTOMER - Google Patents

Description

Composition of a polystyrene resin and a premixed Polymer system, which a polyolefin and a selectively hydrogenated block copolymer of a vinyl aromatic compound and an olefini-

contains an elastomer

The invention relates to new resin compositions, and more particularly Polymer compositions comprising a polystyrene resin, a premixed blend of an olefin resin and a hydrogenated elastomer Block copolymers of a vinyl aromatic compound and a

Weitsrsr

Olefin elastomers alone or / in combination with a polystyrene resin and, optionally, a hydrogenated elastomeric block copolymer of a vinyl aromatic compound and an olefinic elastomer contain.

The brittleness and lack of impact resistance in the out Polystyrene resin molded parts is a well known fact of experience. These difficulties have been tried by it to fix that rubber was incorporated into the polystyrene resins or that resins were produced in which polystyrene was applied to a

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rubbery main chain, for example random styrene / butadiene copolymer, is vulcanized. Unfortunately, such highly resistant polystyrenes weather to a very great extent and are therefore for unsuitable for outdoor use.

Many manufacturers of high impact polystyrenes have attempted to make them from saturated, for example selectively hydrogenated, rubbers. In such rubbers, the olefinically unsaturated fraction is reduced, while the aromatically unsaturated fraction is largely unaffected. These measures included, for example, interpolymerization, which is the common technique normally used to prepare grafted polystyrene-butadiene backbone resins. For this purpose, polybutadiene is dissolved in styrene monomer and after about 7 to 8 percent styrene conversion, a phase inversion takes place in which the continuous phase polybutadiene in styrene monomer becomes the dispersed phase with vigorous stirring. A type of micelle is formed in a polystyrene + styrene monomer phase, the "micelles" looking like small droplets. In this way, emulsified rubbery particles are grafted and partially crosslinked, about 2/3 of which is polystyrene inclusion and about 1/3 is rubber. With a rubber covering of 10% by weight, the percentage by volume of the rubber in the form of the particles is thus typically 30 to ¹ JO %. This particular phenomenon causes a substantial improvement in the impact strength, for example the impact strength in the notched Izod impact test from 0.4 ft.lbs./inch to 2.5 ft.lbs./inch. Unfortunately, however, the rigidity E from 31,000 to 18,000 and the tensile strength from 530 to 195 kgf / cm are greatly reduced at the same time. The flowability is also greatly impaired due to the large proportion of the volume of the "non-flowing" rubber particles. In either case, the main chain is unsaturated and this causes poor resistance to oxygen, ozone, heat and ultraviolet light.

A number of researchers in this particular field have tried to so-called EPDM rubbers, for example ethylene propylene diene terpolymers, to use the styrene resins according to the aforementioned

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ORIGINAL INSPECTED

To stiffen procedural techniques. The difficulty in this case is to find a usable backbone and graft reaction conditions to find. The saturated gum does not have enough reaction sites for proper grafting and crosslinking on. This makes the particles large (10 - 20 ^ u) and soft. During extrusion and injection molding, these particles can easily pass through those that occur during melt flow Shear forces tear, resulting in a fairly dull surface appearance leads.

U.S. Patent 3,810,957 discloses mixtures of selectively hydrogenated Block copolymers and polystyrene. This mixing of a poly

styrene resin with a selectively hydrogenated poly (monovinyl aromatic Hydrocarbon) poly (conjugated diene) poly (monovinyl aromatic Hydrocarbon) block copolymers, for example by grinding, extruding or by mixing in a Banbury mixer produces high-impact thermoplastic molding compounds that have significantly improved weather resistance. The revelation of the aforesaid US Pat. No. 3,810,957 (Lunk) is hereby incorporated in its entirety by this reference. Unfortunately, such molding compounds cause delamination problems in the manufacture of molded articles due to the fact that they are not large amounts of saturated rubber needed to achieve adequate impact resistance levels.

In our own earlier patent application P 2 750 514.2, whose Disclosure content is incorporated into the present application by this reference is a substantial improvement in the creation of high impact combinations of polyphenylene ether resins and styrene resins. The improvement includes the addition of a premixed, easily dispersible polymer system to the combination, for example a polyolefin, which is combined with a rubbery block copolymer and an additional amount of a rubbery block copolymer.

It has now been found that polystyrene resins themselves with regard to impact resistance and processing can be significantly improved by intimately mixing them with a pre-prepared

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mixed easily dispersible polymer system and if desired / an additional amount of a hydrogenated block copolymer.

The compositions obtained show no tendency to delaminate. They still have a high heat distortion temperature, high gloss, high tensile strength, high rigidity, high creep elongation, high resistance to ultraviolet rays, high aging resistance, high heat resistance during processing and good flowability.

It is believed that the surprising effectiveness of the system is due to the special features of "system (b). That System (b) consists of a precompounded mixture of a selectively hydrogenated vinyl aromatic olefin-vinyl aromatic Block copolymers and an olefinic resin, for example polyethylene, polypropylene and ethylene / propylene copolymers in one Weight ratio from 20:80 to 80:20. In any case can increase the dispersibility in component (b) by adding a polystyrene and, in particular, homopolymers of styrene as a dispersing aid in amounts up to 100 parts by weight of the resinous components can be further improved and up to to about 10% by weight of other dispersing agents, such as hydrocarbon resins can also be added.

The new compositions can also be reinforced, for example with glass fibers and with flame retardant additives be made flame retardant in order to further expand their field of application in molded products.

In accordance with the present invention, high impact thermoplastics Compositions created that are intimately mixed contain:

(a) a polystyrene resin and

(b) a premixed composition of 80 to 20 parts by weight an olefinic resin, which is polyethylene or a PoIyoC-olefin resin alone or in / combination with a minor

further

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effective amount of a polystyrene resin and corresponding to 20 to 80 parts by weight of a selectively hydrogenated linear, regular or radial teleblock copolymer of a vinyl aromatic compound (A) _n and (A) _n and an olefinic elastomer (B) of ABA ¹ -, A- (BAB) _n -A-, A (BA) _n B-, (A) ₁ -B-, B (A) ₁ J- or B [(AB) _n Bj ^ -TyP, where η is an integer from 1 to 10 and optional

(c) a selectively hydrogenated elastomeric block copolymer of any of the types listed in (b) above.

Preferred compositions are those in which the ingredient

(a) 99 to 60 parts by weight and component (b) comprises 1 to 40 parts by weight and component (c) comprises 0 to 20 parts by weight of the total weight of components (a), (b) and (c). In particularly preferred compositions, the ingredient comprises

(b) 80 to 20 parts by weight and component (c) 20 to 80 parts by weight the total weight of (b) and (c).

With regard to component (a) disclosed in the aforementioned US Pat. No. 3,810,957, the most suitable polystyrene resins are polymers of vinyl aromatic hydrocarbons produced by the polymerization of at least one alkenyl aromatic hydrocarbon of the benzene series and polymers of styrene and of the ring-substituted styrene include wherein the aromatic core comprises one or more alkyl groups, preferably 1 to ¹ J carbon atoms, such as substituted methyl, ethyl or halogen groups such as chlorine groups. Examples of such monomers are styrene, vinyl toluene, vinyl xylene, vinyl ethylbenzene and divinylbenzene. Suitable monomers also include chain-substituted styrenes such as oC-methylstyrene. These polymers preferably have an intrinsic viscosity of 0.5 to 1.5, and the range from 0.6 to 1.0 dl / g, measured in each case using a 0.25 g / 100 ml solution in toluene, is particularly preferred at 30 ° C.

The most preferred polystyrene resins are those at least 25 weight-? Have polymer units, which from

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vinyl aromatic monomers of the formula:

RC = CH ₂

(Z) _p

are derived, wherein R is hydrogen, alkyl having l _(up to ¹ J carbon atoms or halogen, Z is a member selected from the class consisting of vinyl, hydrogen or alkyl having 1 to 4 carbon atoms: and ρ = 1 to 5. The for the present

Most preferred invention / styrene resins are styrene homo-

polymers.

As for components (b) and (c), the hydrogenated Block copolymers are made by known methods and are commercially available.

Before hydrogenation, the end blocks of these copolymers comprise homopolymers or copolymers / which are preferably composed of alkenyl aromatic hydrocarbons and in particular vinyl aromatic hydrocarbons can be prepared, wherein the aromatic portion can be either monocyclic or polycyclic. Typical monomers include Styrene, o £ -methylstyrene, vinyl xylene, ethyl vinyl xylene and vinyl naphthalene or mixtures thereof. The end blocks (A) and (A) can be the same or different. They are preferably selected from styrene, cC -methylstyrene, vinyl toluene and vinyl xylene and vinyl naphthalene, especially styrene. The central block (B) can be made of, for example, butadiene, isoprene, 1,3-pentadiene and 2,3-dimethyl-butadiene be derived and can have a linear, regular or teleradial structure.

The selectively hydrogenated linear block copolymers are in the US patent 3,333,024 and also further described in the above-mentioned US Pat. No. 3,810,957, the disclosure of these US patents is incorporated into the present application in its entirety by this reference.

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The ratio of the copolymers and the average molecular weights can vary within wide limits, although the molecular weight of the central block should be greater than that of the combined end blocks. It is preferred to form end blocks A having average molecular weights from 2,000 to 100,000 and central blocks B, for example a hydrogenated polybutadiene block having average molecular weights from 25,000 to one million. Even more preferred are end blocks having average molecular weights from 8,000 to 60,000, while the hydrogenated polybutadiene polymer blocks have an average molecular weight between 50,000 and 300,000. The end blocks are preferably 2 to 60 percent by weight. or more, preferably 15 to ^ O by weight? of the entire block polymer. The preferred copolymers are those formed from a copolymer having a hydrogenated / saturated polybutadiene central block wherein 5 to 55 percent or more, preferably 30 to 50 percent, of the butadiene carbon atoms are vinyl side chains.

The hydrogenated copolymers have an average unsaturation reduced to less than 20% of the original value. It is preferred if the unsaturation of the central block B is reduced to 10 % or less, preferably 5 % of its original value.

The block copolymers are formed using techniques based on experience are known per se to the person skilled in the art. The hydrogenation can be carried out using a variety of hydrogenation catalysts such as nickel or kieselguhr, Raney nickel, Copper chromite, molybdenum sulfide and finely divided platinum or others Precious metals on a carrier with a low surface.

The hydrogenation can be carried out at any desired temperature or pressure from atmospheric pressure to

ο
at 21 kg / cm (300 psig) with the usual range between 7 kg / cm ² and 70 kg / cm ² (100 and 1,000 psig) at temperatures of 24 to 315 ° C (75 to 600 ° P) , whereby

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the reaction times are between 0.1 and 2k hours, preferably between 0.2 and 8 hours.

Hydrogenated block copolymers such as Kraton G - 65OO, Kraton G - 6521, Kraton G-I650 and Kraton G-I652 from Shell Chemical Company, Polymers Division, have been found useful in the present invention, with Kraton G-1650 being preferred. Likewise The so-called hydrogenated Solprene from Phillips, in particular the product with the name Solpren-512, are useful.

The radial teleblock copolymers, of which the solprenes are typical examples, can be characterized in that

they have at least three polymeric arms, each

Arm of the radial block polymer non-elastic terminal Segments includes, for example, (A) and (A) as described above are defined. The branches of the radial block polymers contain a terminal non-elastomeric segment which is attached to an elastomeric segment Polymer segment is bound, for example (B) as defined above. The same are in U.S. Patents 3,753,936 (Marrs) and 3,281,383 (Zelinski) and they are selectively hydrogenated by processes known per se. The content of revelation of the two aforementioned US patents are incorporated in their entirety into the present application by this reference. In any event, the term "selectively hydrogenated" is used in the present application to denote polymers in which the elastomeric blocks (B) have been hydrogenated, the non-elastomeric blocks (A) and (A) being unhydrogenated, i. are left aromatic.

As mentioned above, other additives can be included in the compositions be present, such as pigments, e.g. titanium dioxide.

As for component (b), a variety of polyolefins can be used Used in conjunction with the block copolymer to form the premix, in general it is preferred to use polyethylene or a poly-oT-olefin or a copolymer of the o ^ -olefins »

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wherein the ÖC-01efin has 5 to 8 carbon atoms to use. The same can be produced by known methods and are readily available from a number of sources. Particularly polyethylene or polypropylene and their capolymers are preferred and block copolymers such as ethylene-propylene copolymer.

The amount of the elastomeric block copolymers, the polyolefins and the PolystyroldispergierungsmitteIs be _ί if used _/ combined added to the styrene resin and the amount varies from 1 to kO weight? the composition.

Of course, other additives may also be present in the compositions, such as plasticizers, pigments, flame retardants and the like, in amounts ranging from 1 to about 100 parts by weight of the total resinous ingredients (a), (b) and (c) in the Composition/. The ranges listed above for the amounts of the polystyrene resin (a), the precompounded mixture of the polyolefin and the hydrogenated elastomeric block copolymer resin (b) and the hydrogenated elastomeric block copolymer _{resin (c) /} if any, are based solely on such resinous components in the polymer mixture, with others Additives are excluded.

Among the features of the present invention are reinforced compositions, which contain reinforcing amounts of reinforcing agents, such as powder, whiskers, fibers or flakes of metals, for example aluminum, bronze, iron or nickel and non-metals, such as carbon threads, needle-shaped CaSiO ,, Asbestos, TiO, titanate whiskers and glass flakes. Such reinforcing agents are in amounts of, for example, 2 to 90% by weight, preferably 10 to 60% by weight !? available. Particularly preferred Reinforcing agent is fibrous glass.

The method of forming the polymer composition is not critical as long as component (b) is premixed. Any known mixing technique is generally suitable. The preferred one Method includes mixing the polymers and any

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Additives such as the reinforcing agent in powder, granulate and thread-like form - as is currently the case - extrusion the mixing and grinding into pellets, which are used for molding using conventionally used means for shaping normally solid thermoplastic compositions are suitable.

The following examples are intended to explain the invention in more detail without, however, representing a limitation of the invention.

The formulations were made by a general procedure which included mechanical mixing and subsequent co-extrusion in a Werner & Pfleiderer (WP) twin screw extruder at 105-115 ° C (220-210 ° F) and molding into test pieces in a reciprocating snow injection molding machine at about 220 ° C barrel temperature and 60 ° C mold temperature. For the preparation of component (b), the block copolymer and the olefinic resin were first mixed together in a main batch at 204 ° C (400 ° F) in a Werner & Pfleiderer twin screw extruder or in an adequate rubber processing machine. The physical tests were conducted using the following procedures: Izod impact strength on notched 0.32 cm (1/8 in.) Samples; Falling-dart impact tests on 0.32 cm disk-shaped samples; Tensile strength and stiffness on bars according to ASTM Type 1, tensile rate 0.5 cm / min .; Ε module with an extensiometer on rods according to ASTM Type 1; Pull rate 0.5 cm / min .; Flow length at 240 ° C. and 0.3 cm thickness at constant injection rate and pressure; Heat distortion temperature at 18.7 kg / cm (266 psi); and apparent melt viscosity at 1500 sec " ¹ and 282 ° C (5 ^ 0 ° F).

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Examples 1 - 4

The following formulations were prepared, molded

and tested;

Table 1 Compositions of styrene resin and premixes of hydrogenated Block copolymers and polyolefin

Example IA ⁺ 1 i. 1 ί

composition (Parts by weight)

Styrene homopolymer ^a 85 90 80 70 60

Hydrogenated styrene-butadiene-styrene block copolymer ^b - 2.5 5.0 7.5 10

d <(ft thy len-Propy len-Copo Iy

mer ^c '- 2.5 5.0 7.5 10

Styrene homopolymer ^a - 5.0 10.0 15 20

Hydrogenated styrene butadiene

Styrene block copoly-

_mer b ₁₅

properties 92 93 92 91 90 Thermal deformation tempe
temperature ⁰ C 1.910 1,700 1,725 1,920 1,850 Melt viscosity in
Poise 13.6
(2.5) 5.2
(0.95) 7.89
(1.45) 8.43
(1.55) 13.1
(2.4) Notched Izod impact strength
capacity kg / cm (ft.lbs./in) 2.5 0.5 0.8 1.5 2.75 Falling dart strike
strength kg-m. 400 495 430 368 320 Tensile strength kg-m 25,100 2 8,800 26,200 2 4,000 20,600 Ε module kgf./cm ²

Surface appearance high- high- high- high-gloss glossy glossy glossy glossy,

+) Controversy

a) Hoechst N 7000 high heat crystal

b) Shell Chemical Kraton G 165Ο

c) BA-616 Hüls Chemical Co.

d) premix

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The compositions according to the present invention with premixed resins maintained their properties over a wide range of gum contents and yielded excellent impact strength values, even with low levels of block copolymers.

Examples 5-14

The following formulations were prepared, molded and tested:

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ORIGINAL! NSPECTED

75 65 80 70 60 75 65 55 45 i 5.0 7.5 2.5 5 7.5 2.5 5.0 7.5 10 CTl
ι 5.0 7.5 2.5 5 7.5 2.5 5.0 7.5 10 10 15th 5 10 10 10 15th 15th 15th 5 5 10 10 10 15th 15th 15th 15th

Table 2

. I Composition of styrene resin and a premix of hydrogenated block

copolymers and polyolefin

Example 5 £ 7 £ 10 11 12 Il

Composition (weight
fi parts)

iii styrene homopolymer 85

[Hydrogenated styrene-butadiene-styrene block copolymer ° 2.5

Q d ^ Äthyletv-Propylen-Copoly- _Ä pierb '2,5

* | j3tyrene homopolymer ^a 5

κ »Hydrogenated styrene-butadiene-ς

"* -. Styrene block copolymer * ^{3 5}

to properties

^, Heat deformation temperature

temperature ⁰ C 92 91 90 91 89 89 90 89 87 88

Melt Viscosity (Pois.) 1,760 1,840 1,920 1,820 I.86O I.900 1,975 1,990 2,080 2,150 Izod impact strength

speed kg / cm 1.62 9.25 12.0 10.9 13.9 19.6 15.8 23.1 28.8 34.3

Palling dart punch

strength kg-m 1.4 1.8 3.1 2.7 3.5 4.3 4.1 4.6 5.1 6.4 tensile strength kgf / cm ² 410 375 335 385 370 310 390 315 290 23Ο £ > Ε module kgf / cm ² 26,800 24,200 23,200 25-300 23,100 21,000 22,700 20,200 18.3ΟΟ 17,000co Surface appearance high-high-high-high-high-medium-high-medium-medium. mittetco

glossy, glossy, glossy, glossy, glossy, glossy, glossy, glossy. _(jy

a) Hoechst N 70000 high heat crystal, b) Shell Chemical Kraton G I650 c) BA-616 Huls Chemical Co., d) Premix

The above data shows that in accordance with the present invention high impact polystyrene can be obtained in which all other important properties are excellently retained will.

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ORIGINAL INSPECTED

Claims (1)

Claims 1. High impact thermoplastic composition, thereby , characterized in that it contains an intimate mixture : (b) a premixed composition of 80 to 20 parts by weight of an olefinic resin made of polyethylene or a poly-oC-olefin resin, alone or in further combination with a small effective amount of a polystyrene resin and correspondingly 20 to 80 parts by weight of a selectively hydrogenated elastomeric linear regular or radial Partial block copolymers from a polymerized vinyl aromatic compound (A) and (A) /: and an olefinic elastomer (B) of ABA ¹ -, A- (BAB) _n -A-, A (BA) _n B-, (A) _Jf B -, B (A) ₁ , - or B f (AB) bJ h type, where η is an integer from 1 to 10 and optional (c) a selectively hydrogenated elastomeric copolymer of one of the types mentioned in (b). 2. Composition according to claim 1, characterized that the component (a) 99 to 60 parts by weight and the component (b) 1 to 40 parts by weight and the Component (c) comprises 0 to 20 parts by weight of the total weight of components (a), (b) and (c). 3. Composition according to claim 1, characterized that the component (b) 80 to 20 parts by weight and the component (c) 20 to 80 parts by weight of the total weight comprised by (b) and (c). 909812/093 ^ ORIGINAL INSPECTED Composition according to any one of the preceding claims, characterized in that component (a) is a polystyrene resin with at least 25% polymer units derived from a vinyl aromatic compound of the formula are derived, wherein R is hydrogen, alkyl having 1 to * t carbon atoms or halogen, Z is hydrogen, alkyl having 1 to I ¹ carbon atoms or vinyl, and ρ is an integer from 1 to 5. 5. Composition according to claim 4, characterized in that the polystyrene resin is a styrene homopolymer resin is. 6. Composition according to one of the preceding claims, characterized in that in components (b) and (c) the vinyl aromatic compounds (A) and (A) are selected from styrene, oC -methylstyrene, vinyltoluene, vinylxylene and vinylnaphthalene and the elastomer (B) is selected from polymerized butadiene, isoprene, 1,3-pentadiene or 2,3-dimethylbutadiene. 7. Composition according to claim 6, characterized in that in the (b) and (c) components (A) 1
is a polystyrene block and (A) is a polystyrene block. 8. Composition according to one of the preceding claims, characterized in that in the. (B) and (c) -Existing end blocks (A) and (A) each have molecular weights of 2,000 to 100,000 and the central block (B) has a molecular weight of 25,000 to one million. 9. Composition according to any one of the preceding claims, characterized in that in the (b) component the olefinic resin polyethylene, polypropylene or is an ethylene-propylene copolymer. 10. The composition according to claim 1, characterized in that the polystyrene resin in the (b) component comprises a styrene homopolymer. 90981 2/0939 ORIGINAL INSPECTED