DK156960B - THERMOPLASTIC FORMULA MIXTURE WITH GREAT SHOCK STRENGTH AND INCLUDING A POLYPHENYLENETHER, A POLYSTYRENE RESIN AND AN ELASTOMER - Google Patents

Description

DK 156960 B

The invention relates to a high impact thermoplastic resin composition comprising 1-99% by weight of a polyphenylene ether of the general formula: - Q -, 10 - Q wherein the oxygen atom of a repeat unit is connected to the benzene nucleus of the subsequent unit, n is an integer greater than 15 or equal to 50, and each Q represents a monovalent substituent selected from hydrogen or halogen atoms, hydrocarbon groups containing no tertiary α-carbon atom, halogen-substituted hydrocarbon groups having at least two carbon atoms between the halogen atom and the phenyl group, hydrocarbon oxy groups or halogen substituted hydrocarbon oxy groups having at least two carbon atoms between the halogen atom and the phenyl group, 99-1% by weight of a polystyrene resin, calculated on a rubber-free basis, and 0.1-30% by weight, calculated on the basis of the weight of the total mixture, of an elastomer phase dispersed in the mixture as a batch of clothing in the form of: 25 a) rubber batch, b) poly (c) a mixture of (a) and (b).

30 hpj molecular weight polyphenylene ethers are highly useful technical thermoplastic resins with relatively high melt viscosities and blood fermentation points, i.e. over 275 ° C. They are useful for many commercial forms requiring high temperature resistance and can be molded into foils, fibers and moldings.

Certain properties of the polyphenylene ether are unsuitable for certain commercial applications. Eg. are objects formed of polyphenylene ethers, some scour as a result of low impact strength.

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Furthermore, the relatively high melt viscosities and melting points make the processing of the melt difficult under commercial conditions, since high temperatures must be used for blending the polymer and because of such high temperatures 5 instability and discoloration problems arise. The melt-up work also requires specially designed treatment equipment for use at elevated temperatures.

In the specification of US Patent No. 3,383,435, a process is described for improving the melt workability of polyphenylene ethers by mixing them with polystyrene resins, preferably high impact strength rubber modified polystyrenes. Mixtures of poly (2,6-dialkyl-1,4-phenylene) ethers and a high impact polystyrene are commercially important as they both provide an improvement in the melt workability of the polyphenylene ether and an improvement in the impact resistance of articles formed by the mixtures. It is generally recognized that the properties of impact resistant polystyrene resins are highly dependent on the number, size and nature of 20 elastomer particles dispersed in the resin. There is an optimal particle size in the range of 2 to 5 or 10 µm for rubber-modified, impact-resistant polystyrene with a relatively narrow size distribution within this range, cf. eg. Encyclopedia of Polymer Science and Technology, Volume 13, 1970, page 392 and the descriptions of British Patent Nos. 1,127,820 and 1,174,214.

In the disclosure of U.S. Patent No. 3,487,127, a process for producing a rubber-modified aromatic vinyl polymer such as polystyrene is disclosed in which a rubber, such as polybutadiene, is dissolved in styrene and the styrene is polymerized until obtained. a conversion of 10-45% by preparing an aqueous suspension and initiating a suspension polymerization from the mixture formed and 2-20% polyphenylene oxide relative to the total weight of the polymer. It is stated that the plastic composition thus obtained comprises polyphenylene oxide and a copolymer of polybutadiene and styrene, and that it has good properties in terms of impact strength, hardness and thermal deformation temperature.

The object of the present invention is to provide one

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3 resin composition of the kind mentioned in the introduction has a greater impact strength than the compositions known from the aforementioned US patent and which has a greater resistance to attack of solvents relative to the compositions known from the latter US patent. (See subsequent Comparative Example 1).

This form is achieved with the plastic composition according to the invention, which is characterized in that the elastomer particles have a maximum mean diameter of approx. 2 pm.

10

The blends consist of two phases, the continuous phase being a matrix of polyphenylene oxide resin and styrene resin in which a discontinuous phase comprising particles of an elastomer is dispersed. These particles may, to varying degrees, comprise polystyrene resin depending on how the blends are prepared. In any case, the size of the particles can be measured by means well known to those skilled in the art, e.g. either by phase contrast microscopy, which is particularly convenient, or by microfiltration, whereby the polystyrene matrix is dissolved with a suitable solvent which does not dissolve the elastomer particles, and the "solution" is filtered through a very fine filter retaining the elastomer particles, and similar known methods.

The polystyrene resin and elastomer can be combined with the polyphenylene ether as separate constituents or better, as smaller amounts of elastomer appear to provide similar impact strengths, a polystyrene resin containing dispersed elastomer particles can be combined with the polyphenylene ether. According to the first method, the particle size is controlled by the elastomer phase, e.g. it is reduced by mechanical mixing of the rubber, the styrene resin and the polyphenylene oxide resin. According to the second method, the particle size of the elastomer is provided e.g. by polymerizing styrene in the presence of dissolved rubber under well-known conditions, whereby a dispersed elastomer phase of e.g. grafted cross-linked rubber particles are dispersed in a polystyrene matrix. This is then combined with the polyphenylene ether and the particle size remains largely unchanged in the final mixture.

The polyphenylene ethers pertaining to the present invention are

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4 well known and are e.g. disclosed in the specifications of US Patent Nos. 3,306,874, 3,306,875, 3,257,357 and 3,257,358.

Many examples of polyphenylene ethers of formula I can be found in the above-mentioned US patents.

In the context of the present invention, a preferred group of polyphenylene ethers of formula I and wherein each Q represents alkyl of from 1 to 4 carbon atoms comprises compounds such as e.g.

Poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether) , poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether and poly (2-ethyl-6-propyl-1,4-phenylene) Particularly preferred is poly (2,6-dimethyl-1,4-phenylene) ether which readily forms a compatible single-phase mixture with polystyrenes over the entire range of combination ratios.

As used herein, the term "polystyrene" as defined below has the same meaning as in the aforementioned U.S. Patent No. 3,383,435, see e.g. column 3, lines 20-45. Such polystyrenes may be combined with polyphenylene ether and will generally be selected from those containing at least 25% by weight of the polymeric units derived from a vinyl aromatic monomer, e.g. one having the formula: 25 BC - CH2

. 4- <z> P

Wherein R is hydrogen, (lower) alkyl, e.g. with from 1 to 4 carbon atoms or halogen, Z represents hydrogen, vinyl, halogen or (lower) alkyl, and p is 0 or an integer of from 1 to 5. Illustrative polystyrene resins include homopolymers of polystyrene, polychlorostyrene, poly methyl styrene and styrene-containing copolymers, such as styrene-acrylonitrile copolymers, copolymers of

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5 ethylvinylbenzene and divinylbenzene and styrene-acrylonitrile-α-methylstyrene polymers. Preferred polystyrene resins within this group are homopolystyrene, poly-α-methylstyrene, styrene-acrylo-nitrile copolymers, styrene-or-methylstyrene copolymers, styrene-methyl-5-methacrylate copolymers, and poly-α-chlorostyrene. Homopolystyrene is particularly preferred.

The term "rubber" as used herein encompasses polymeric materials, natural and synthetic, which have rubber properties at room temperature, e.g. 20 to 25 ° C. The term "rubber" therefore encompasses natural or synthetic rubber species of the type commonly used in the manufacture of impact-resistant resins. All these gums will form a two-phase system with the resin, e.g. a polystyrene, and will comprise the discontinuous particulate phase of the impact resistant polystyrene resin composition. Illustrative gums for use in the present invention are natural rubber and polymerized diene gums, e.g. polybutadiene and polyisoprene and copolymers of such dienes and vinyl monomers, e.g. vinyl aromatic monomers, such as styrene. Examples of suitable gums 20 or rubber-like copolymers are natural raw rubber, synthetic rubber of the SBR type containing from 40 to 98% by weight butadiene and from 60 to 2% by weight styrene made by either hot or cold emulsion polymerization, GR-N synthetic rubber. the type containing from 65 to 82% by weight of butadiene and from 35 to 18 to 25% by weight of acrylonitrile, and synthetic rubbers made from e.g. butadiene, butadiene styrene or isoprene e.g. by methods using heterogeneous catalyst systems such as a tri-alkyl aluminum and titanium halide. Among the synthetic rubber species which can be used in the preparation of the present compositions are 30 elastomer-modified diene homopolymers, e.g. hydroxy- and carboxy-terminated polybutadiene; polychlorobutadiene, e.g. neoprenes; polyisobutylene and copolymers of isobutylene and butadiene or isoprene, polyisoprene, copolymers of ethylene and propylene and copolymers thereof with butadiene; thio rubber gums, polysulfide gums, acrylic gums, polyurethane gums, dienes copolymers, e.g. butadiene and isoprene with various monomers such as alkyl unsaturated esters, e.g. methyl methacrylate, unsaturated ketones, e.g. methyl isopropenyl ketone; vinyl heterocyclic compounds, e.g. vinyl pyridine; polyethergummiarter; epichlorhydringummiarter.

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The preferred gums include polybutadiene and rubbery copolymers of butadiene and styrene. These preferred gums are widely used in the production of high impact polystyrene resins which contain dispersed elastomer particles having the wide range of elastomer particle sizes mentioned in the literature cited above.

The term "rubber-modified polystyrene resin" defines a group of compounds comprising a two-phase system wherein rubber is dispersed in a polystyrene matrix in the form of discrete portions of clothing. The particles can be formed by mechanical mixing of the rubber and polystyrene, in which case portions of the rubber will constitute the dispersed elastomer phase. On the other hand, and this is preferred, the two-phase system may consist of copolymers of a styrene monomer and an elastomer or rubber. Commercially, such high impact polystyrenes are usually produced by grafting on a rubbery polymer in the presence of polymerizing styrene. Such systems consist of a continuous phase of polymerized styrene monomer in which the rubber is dispersed in a discontinuous elastomer phase with or without 20 grafted chains of polymerized styrene monomer. The particles may also contain occluded polymerized styrene monomer, and this does not affect their size.

Methods for preparing rubber-modified polystyrenes of controlled particle size are known. Thus, in the disclosure of British Patent No. 1,174,214, a polymerization of rubber in admixture with styrene monomer is described, the polymerization being penetrated while stirring in the initial stages to form a copolymer of the desired particle size. The surround is then reduced and the polymerization is completed. According to the procedure described by Bender in J. App. Polymer Sci., Vol. 9, pp. 2887, 1965, a prepolymerization of rubber in admixture with styrene monomer is stirred until the desired particle size is obtained, then water and surfactants are added and the polymerization is fully extruded in suspension.

In these resins, the elastomer will preferably be derived from butadiene, from a butadiene styrene copolymer or from a mixture thereof. These materials can be made by well known processes.

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7 ways, e.g. those mentioned above. They are also commercially available from a variety of sources, e.g. from Foster Grant,

Inc., U.S.A. under the product designation "No. 834".

As described in the specification of U.S. Patent No. 3,383,435, polyphenylene ethers and polystyrene resins can be combined with each other in all ratios and have only a set of thermodynamic properties. The present compositions of the invention comprise from 1 to 99% by weight of polyphenylene ether and from 99 to 1% of polystyrene on a rubber-free basis. In general, mixtures are preferred in which the polystyrene resin on a rubber-free basis is from 20 to 80% by weight of the polystyrene and the polyphenylene ether, since after forming they have the best combination of impact strength, surface appearance and resistance to solvents. Particularly useful and preferred are mixtures in which the polystyrene resin on a rubber-free basis is from 40 to 60% by weight of the total weight of the polystyrene and polyphenylene ethers. Properties, such as bending strength, tensile strength, hardness and especially impact strength, have been found to reach a maximum in connection with these preferred blends.

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The rubber content or weight percent of the dispersed elastomer phase in the present compositions varies between 0.1 and 30 percent by weight of the total weight of the mixture. If the elastomer phase content falls below approx. 0.1% by weight, the impact properties decrease. The preferred range for elastomer phase content is from 1 to 15% by weight, the highest amount being used when the rubber is dispersed by mechanical mixing. If the elastomer is preferred in the form of a styrene-grafted rubber copolymer, the lower amounts may be convenient. In all cases, the preferred amount of elastomer phase will be between 1.5 and 6% of the total weight of the mixture. While the impact strength of art is optimized by greater content, other properties are affected, such as solvent resistance and the appearance of shaped objects as well. Since the grafted with styrene grafted garments provide mixtures with better impact strength 35 than those obtained by mechanical mixing, i.e. Non-grafted particles, to the optimum extent 1.5 to 6% by weight, it is especially preferred that the compositions of the present invention contain lots of styrene-grafted rubber as elastomeric phase.

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The process used to prepare the polyphenylene-ether-polystyrene rubber blends of the present invention is not critical, provided that it allows the maximum mean pressure of the elastomer particles to be reduced to or maintained at 2/2 and preferably between 0.5 and 2 / an. The preferred process is one in which the polyphenylene ether is mixed with polystyrene and a rubber or a rubber-modified polystyrene using commonly known mixing methods, and the mixture thus prepared is given some kind of form such as extrusion, hot molding and the like.

Other additives, such as blasting agents, pigments, flame retardant additives, reinforcing agents, such as glass filaments or fibers, stabilizers and the like may be contained in the present compositions.

It has been found that mixtures of polyphenylene oxide and equal amounts of polystyrene and rubber-modified polystyrene with elastomer particle sizes of 1 to 2 microns have impact strengths that are comparable to the impact strength of known mixtures of the same polyphenylene ether content, but wherein the polystyrene is rubber modified and has an elastomer particle size of approx. 4 / an. Not only are these mixtures more economical to prepare than the prior art mixtures, but they also have improved surface appearance after injection molding.

The present invention will be further elucidated in the following Examples wherein, unless otherwise stated, all of the mixtures are prepared by passing mixtures of the polyphenylene ether, styrene 30 and the rubber, or other ingredients, if any, through an extruder having single screw and variable rise at extrusion temperatures between approx. 232 ° C and 288 ° C. All parts are weighted. The strands emitted from the extrusion apparatus are peeled off, chopped into pellets and formed into sample bars 35 using generally known methods.

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Example 1 22.7 kg of the following composition were mixed together: 5 Material Parts

Poly (2,6-dimethyl-1,4-phenylene) ether ^ 45

Rubber modified polystyrene ^ 55

Polyethylene 1.5 10 Tridecyl Phosphite 0.5

Acravox 0.25

Titanium Dioxide 2 General Electric Company, "PPO" polyphenylene ether in pellet form.

15 ^ Foster-Grant, Inc., "No. 834" High impact polystyrene (prepared as described in pages 6, 1. 14-16) in pellet form with a dispersed elastomer phase having an average particle size of 1-2 µM and a polybutadiene content of ca. 9% by weight.

The mixture was extruded in a 63.5 mm Prodex extruder.

The resulting strands were cut off, chopped into pellets and formed into sample pieces. The average particle size of the elastomer phase in the mixture remained 1-2 µm.

The following physical properties are obtained:

Izod impact strength (N * m / cm notch radius) 3.0

Gardening impact strength (N »m) 27.1

Fracture elongation (%) 48 -5 30 Heat throw temperature (18.2 x 10 Pa ° C) 124

Tensile flow voltage (10 ~ 5 Pa) 655 -5

Maximum load (10 Pa) 579 45 ° gloss value 62 Bending modulus (10 “® Pa) 24.146 -5 35 Bending tensile strength (10 Pa) 1.879

In comparison, the procedure of Example 1 was repeated, replacing the Foster-Grant "No. 834" component with Monsanto® HT-91 rubber-modified polystyrene (elastomeric phase) with high impact strength,

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10 dispersed elastomer phase with a mean particle size of about 6 μιη (range 2-10) and a polybutadiene content (rubber content) of approx. 9% by weight. After mixing, the mixture contains a rubber phase with a particle size of approx. 6 / «n. The following physical properties are obtained:

Izod impact strength (N * m / cm notch radius) 0.96

Gardening impact strength (N * m) 22.6

Fracture elongation (%) 51

-R

10 Heat throw temperature (18.2 x 10 Pa ° C) 131 -5

Tensile flow voltage (10 Pa) 669 -5

Maximum load (10 Pa) 565 45 ° gloss value 59

Starting modulus (10 ~ 5 Pa) 26,262 15 Tensile strength (10 ~ 5 Pa) 2,100

A comparison of the results obtained shows a significant improvement in the impact strength measured at the Izod and Gardner ranges as well as with respect to the overall appearance (as seen by the gloss value) of the mixture containing particles of 1-2 μια compared with that containing particles with a diameter of 6 µm.

25 30 35

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Example 2 22.7 kg of the following self-extinguishing composition were mixed together: 5

Matter of all parts

Poly (2,6-dimethyl-1,4-phenylene) ether ("PPO") 50

Rubber Modified Polystyrene ("No. 834") 50 10 Polyethylene 1.5

Triphenyl phosphate 3.0

Tridecyl Phosphite 1.0

Zinc sulphide 1.5 30% styrene Master Batch Black 0.5 15

After extrusion into a 63.5 mm Prodex extrusion apparatus, the strands were cut off, chopped, and formed into sample rods by commonly known methods. The average particle size in the elastomer phase is 1-2 µm The following physical properties are obtained: 20

Izod impact strength (N * m / cm notch radius) 2.7

Gardening impact strength (N * m) 19.8

Fracture elongation (%) 49

Heat throw temperature (18.2 x 10 "® Pa ° C) 122 25 Tensile flow voltage (10 ~ ® Pa) 627 -5

Maximum load (10 Pa) 565

Starting module (10 "Pa) 23,566

Initial tensile strength (10 "® Pa) 1.794 30 By comparison, the procedure of Example 2 was repeated, with Foster-Grant" no. The 834 "component was replaced with Monsanto® polystyrene HT-91 with a dispersed elastomer phase having a mean particle size of about 6 μπι (range 2-10). The finished mixture has a particle size in the same range. The following 35 physical properties were obtained:

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Izod impact strength (N * m / cm notch radius) 0.96

Gardner impact strength (N «m) 13.6

Fracture elongation (%) 40 -5 5 Heat throw temperature (18.2 x 10 PaeC) 121 -5

Tensile voltage (10 Pa) 645 -5

Maximum load (10 Pa) 572

Beginning module (10 ~ 5 Pa) 23,391

Bending tensile strength (10 ~ Pa) 32,128 10

A comparison of the results obtained shows a significant improvement in the impact strength of mixtures containing dispersed elastomer with batches having a maximum diameter of 2 μχα.

Example 3 22.7 kg of the following self-extinguishing composition were mixed together:

Material Parts 20

Polyphenylene Ether ("PPO") 40

High strength polystyrene ("No. 834") 60

Polyethylene 1.5

Tridecyl Phosphite 0.5 Triphenyl Phosphate 9

Teflon 0.1

After extrusion into a 63.5 mm Prodex extrusion apparatus, the strands are cooled, chopped and formed into sample pieces by commonly known methods. The mean particle size in the rubber phase was 1-2 µm. The following physical properties are obtained:

Izod impact strength (N * m / cm notch radius) 2.83

Gardner impact strength (N * m)> 27.1 35 Elongation at break (%) 55

Heat throw temperature (18.2 x 10 105 Pa ° C) 103 -5

Tensile flow voltage (10 Pa) 552 -5

Maximum load (10 Pa) 512 45 ° gloss value 61.5

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For comparison purposes, the procedure of Example 3 was repeated, replacing the Foster-Grant "No. 834" component with Monsato® HT-91 polystyrene with high impact strength and an average particle size of 6 / an (range 2-10 / an) · The finished mixture has a particle size in this range. The following physical properties are obtained:

Izod impact strength (N * m / cm notch radius) 0.96

Gardening impact strength (N * m) 5.6

Fracture elongation (%) 42 -5 10 Heat throw temperature (18.2 x 10 PaeC) 99

Tensile flow voltage (10Pa) 593 _5

Maximum load (10 Pa) 496

A comparison of the results obtained shows a significant improvement in the impact strength of mixtures containing dispersed elastomer with portions of cl, having a maximum diameter of 2 / tm.

Example 4 20 22.7 kg of the following composition were mixed together:

Material DeTe

Polyphenylene Ether ("PPO") 30 High impact polystyrene ("No. 834") 70

Polyethylene 1.5

Tridecylphosphite 0.5

Triphenyl Phosphate 6 After extrusion in a 63.5 mm Prodex extrusion apparatus, the strands were cut off, chopped into pellets, and formed into samples by conventional techniques. This mixture containing approx. 68% by weight styrene resin (rubber-free basis) based on the total weight of rubber-free styrene and polyphenylene ether 35 and approx. 5.8% dispersed elastomer phase having a particle diameter of 1-2 microns, had a higher impact strength (2.6 versus 0.91) than that recommended for similar blends according to the prior art made from rubber-modified polystyrene. the particle size is 2-10 µm (cf.

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14 3,383,435). The following physical properties are obtained:

Izod impact strength (N »m / cm notch radius) 2.6

Heat throw temperature (18.2 x 10 x Pa Pa) 108 5 Break elongation (%} 44 -5

Tensile flow voltage (10 Pa) 517

Example 5 10 22.7 kg of the following composition were mixed together:

Hate all parts

Polyphenylene Ether ("PPO") 15 High impact polystyrene (Foster Grant "No. 834") 75

Polyethylene 1.5

Tridecylphosphite 0.5

Triphenyl Phosphate 6 20 After extrusion into a 63.5 mm Prodex extrusion apparatus, the strands were cut off, chopped into pellets and formed into sample pieces. The dispersed batches of the elastomer phase were on average between 1 and 2 µm in diameter. The following physical properties are obtained: 25

Izod impact strength (N * m / cm notch radius) 2.1

Fracture elongation (%) 34

Heat throw temperature (18.2 x 10 ”5 PaeC) 106

Tensile Flow Voltage (10 "Pa) 517 30 Maximum Load (10-5 Pa) 496

A similar blend according to the prior art using Monsanto® HT-88 high impact polystyrene and a particle size of 2-10 µηι (cf. the description of US Patent No. 3,383,435, Example 7 and Fig. 18 ) had a impact strength of only approx. 0.91 N * m / cm notch radius.

Sample bars made from the mixtures of Example 1

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15 and 2 and immersed in gasoline at a voltage of 1%, did not undergo catastrophic failure over the course of 15 minutes, and the particle size averaged from 1 to 2 µl (Foster-Grant "No. 834"). For comparison, all sample bars made from mixtures in which the particle sizes were larger (Monsanto® HT-91) underwent (catastrophic failure) in less than 15 seconds at 1% voltage in gasoline.

Example 6 10

Three mixtures were prepared by mixing the following components:

Materials _ Parts_ 15

ABC

Poly (2,6-dimethyl-1,4-phenylene) ether (PPO) 40 40 40 20 Rubber-modified polystyrene: (Cosden, "825 TV", 3-8 [m) 65 (Koppers, "Dylene 601", 3- 10 μια) 65 25 (Koppers, "PRX 1005", 1-2 / on) - - 65 In each of the polystyrenes, the rubber content consisted of 7.5% by weight of polybutadiene which was grafted to polystyrene.

Thirty-three mixtures were extruded through a 19.05 mm Wayne extruder and formed into an 85 g Newbury molding machine. The individual blends contained a dispersed elastomer gel having a particle diameter similar to that of this respective rubber-modified styrene. The physical properties were as follows: 35

Blandina ABC

Izod impact strength N «m / cm notch radius) 0.91 0.98 2.04

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Tensile flow voltage (10 ’Pa) 662 621 627

Fracture strength (10 "5 Pa) 538 527 510 5 Extension (%) 36 46 47

It is seen that blend C (according to the invention) has a impact strength that far exceeds the impact strength of A and B. These results show that these properties are obtainable with the same rubber content using rubber particles at a size of 1- 2 µm instead of 3-10 µm, commonly found in commercially available rubber-modified polystyrenes, and which have heretofore been used in polyphenylene ether mixtures according to the prior art.

Example 7

A mixture was prepared by the procedure of Example 1 except that half of the Foster Grant "No. 834" rubber modified high strength polystyrene was replaced with 20 crystalline polystyrene (Monsanto® HH-101). The compositions were as follows:

Material _ Parts

DEF

Poly (2,6-dimethyl-1,4-phenylene) ether ("PPO") 45 45 45

Rubber Modified Polystyrene: 30 (Foster Grant "No. 834", 1-2 µm) 55 27.5 (Monsanto® HT-91, 2-10 µπι) - 55 35

Crystalline polystyrene (Monsanto®, HH 101) - - 27.5

Polyethylene 1.5 1.5 1.5

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Tridecylphosphite 0.5 0.5 0.5

Acravox 0.25 0.25 0.25 Titanium Dioxide 2 22

After extrusion, the mixtures contained dispersed elastomer particles of the same diameter as found in the starting materials. Specimens made from the respective mixtures had the following 10 properties:

Properties D E F

Izod impact strength 15 (N * m / cm notch radius) 3.0 0.96 0.91

Melt Viscosity (Pa-s) 254 260 235

Extension (%) 48 51 59 20

Heat throw temperature ° C 124 131 138

It is seen that mixing Foster Grant "No. 834" material (with 1-2 25 μπι lot of clothing) with a substantial portion of rubber-free styrene resin provided blend F, which was much cheaper to produce, retained the impact strength properties of blend B, which had the double rubber content compared to mixture F. It is noteworthy that the heat-casting temperature of F is better than that of E.

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Example 8 In the mixture of Example 1, the poly (2,6-dimethyl-1,4-phenylene) ether was replaced with the following polyphenylene ethers: poly (2,6-diethyl-1,4-phenylene) ether, poly (2-methyl-ether). 6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2,6-di-propyl-1,4-phenylene) ether,

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18 poly (2-ethyl-6-propyl-1,4-phenylene) ether.

The finished blends had properties similar to those of the blend according to Example 1.

5

Example 9

A mixture containing 50 parts of poly (2,6-dimethyl-1,4-phenylene) ether, 45 parts of polystyrene resin and 5 parts of 10 rubber was prepared. First, the rubber and polystyrene resin are intimately blended into one

Banbury mixer until the rubber particles are reduced to an average diameter of 1 to 2 µm, after which the mixture is coextruded with the polyphenylene ether and a uniform mixed composition with elastomer particle sizes is obtained in the range of 1 to 2 μιη. This mixture is chopped off after pelletizing and molded into specimens exhibiting high impact strength and improved performance.

The following polystyrene resins were used in the mixture: 20 poly-α-methylstyrene, styrene-acrylonitrile copolymer (27% ACN), styrene-α-methylstyrene copolymer, styrene-methyl methacrylate copolymer, 25-poly-α-chlorostyrene and styrene-acrylic in tri1-α-methylstyrene,

And the following rubber types: 30 natural raw rubber, styrene-butadiene copolymer rubber (23.5% STY), acrylonitrile-butadiene copolymer rubber (18% ACN), methylisopropenyl ketone-butadiene copolymer rubber (50% MIK), and ethylene-propylene rubber butadiene rubber butadiene copolymer rubber.

35

Comparative sex example 1

Upon examination using an interference contrast microscope of a product made according to U.S. Patent No. 3,487,127, 19

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it was found that the mean diameter of the rubber portion included in the product was approx. 4 / zm, and that the largest portion at is had a diameter of approx. 8 / zm.

In order to illustrate the properties of a plastic composition according to the invention and the properties of a polymeric composition according to US Patent 3,487,127 and with the above-mentioned average particle diameter of the rubber particles, two mixtures were prepared from 45 parts by weight of poly (2,6-dimethyl). 1,4-polyphenylene) ether, 55 parts by weight of rubber-modified polystyrene (styrene polymerized in the presence of dissolved polybutadiene), 1.5 parts by weight of polyethylene, 0.5 parts by weight of tridecylphosphite, 0.25 parts of Acrawax and 2 parts of titanium dioxide. The blends are extruded in string form using a variable pitch screw extruder at a temperature of between 232 ° and 316 ° C. In one of the products thus manufactured, the size of the rubber particles was approx. 1.5 µm and in the second approx. 4 / zm. In both cases, the gel content was below 22%, namely 21.5% and 21%, respectively.

The extruded strands were cooled and then cut to form pellets, which were then ejected in the form of barbs.

The durability of the products was determined by applying specimens held below a 1% starting voltage in gasoline at a temperature of approx. 23eC. A record was made of the time interval that elapsed before a final break of the test subjects occurred.

The results obtained are shown in the following Table I.

Table I 30

Particle - Time to enter

Product% Gel_stflrrel se_trade of fracture_ A 21.5 1.5 / zm over 20 min.

B 21 4 / zm 42 sec. and 300 sec. (two provisions) 35 20

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As can be seen from the above, the product of the invention has a far greater resistance to gasoline attack than a similar product according to US Patent No. 3,487,127.

5 10 15 20 25 30 35

Claims (8)

A high impact thermoplastic plastic composition comprising 1-99% by weight of a polyphenylene ether of the general formula: wherein the oxygen atom of a repeat unit is connected to the benzene nucleus of the following unit, n is a whole numbers greater than or equal to 50 and each Q represents a monovalent substituent selected from hydrogen or halogen atoms, hydrocarbon groups containing no tertiary α-carbon atoms, halogen-substituted hydrocarbon groups having at least two hydrocarbons between halogen the atom and the phenyl group, hydrocarbon groups or halogen-substituted hydrocarbon groups having at least two carbon atoms between the halogen atom and the phenyl group, 99-1% by weight of a polystyrene resin, calculated on a rubber-free basis, and 0.1-30% by weight, calculated on the basis of the total the weight of the blend, of an elastomeric phase dispersed in the blend as a batch of garments in the form of: a) rubber batch garments, b) polystyrene grafted rubber pads or (c) a mixture of a) and b) characterized in that the elastomer particles have a maximum mean diameter of approx. 2 / zm. 2. A plastic composition according to claim 1, characterized in that the mean diameter of the dispersed elastomer particles is from 0.5 µm to 2 µm. A plastic composition according to claim 1, characterized in that the DK 156960 B polystyrene resin comprised from 20 to 80 and preferably from 40 to 60% by weight of the total weight of the polystyrene resin and the polyphenylene ether. 4. Plastic compound according to claim 1, characterized in that the elastomer phase comprised from 1 to 15% and preferably from 0.5 to 6% of the total weight of the mixture. 5. Plastic compound according to any one of claims 1-4, 10, characterized in that it comprises polystyrene containing dispersed elastomer particles and polystyrene grafted with elastomer particles. 6. Plastic compound according to claims 1, 4 and 5, characterized in that the elastomer is polybutadiene. 7. A plastic composition according to claim 1, characterized in that the elastomer phase is a styrene-butadiene graft copolymer. 8. A compound according to claim 1, characterized in that Q is an alkyl group having from 1 to 4 carbon atoms, preferably a methyl group. 25 30 35