DE2229550A1 - Stabiliser combination - for polyphenylene ether/polystyrene compsn, comprising phosphite/tin mercaptide or metal hypophosphite - Google Patents

Abstract

Thermoplastic resin compsn. with (a) a generally unstable polyphenylene ether component and (b) a polystyrene resin component is stabilised with 0.1-10 wt.% (w.r.t. resin compsn.) of a mixt. of (c) a phosphite and up to an equal wt. of (d) a Sn mercaptide or (e) a metal hypophosphite. The compsn. is suitable for making films, fibres and mouldings, esp. in white or pastel colours. The use of (d) or (e) in conjunction with (c) gives stabiliser system with a very high degree of efficiency, esp. in terms of stability towards heat and light. The compsn. has good initial whiteness and flexibility retention.

Description

Stabilized polyphenylene ether / polystyrene resin compositions. The invention refers to thermoplastic masses with a content of polyphenylene ether, Polystyrene resin and a stabilizer that is a phosphite and either a tin mercaptide or contains a metal hypophosphite0 The polyphenylene ether resins are from US patents 3,306,874, 3,306,875, 3,257,357 and 3,257,358 are known. They become oxidative through Coupling of a phenolic compound preferably in an inert solvent and in present a catalyst complex prepared from a Copper salt and an amine was formed. The resins are used in molding and extrusion for the production of articles with excellent hydrolytic stability, excellent dielectric properties and usability in a wide temperature range used.

Examples of the polyphenylene ethers belong to a group of the formula I. in which R and R1 represent monovalent substituents from the group of hydrogen, halogen and hydrocarbon radicals, halogenated hydrocarbon radicals with at least 2 carbon atoms between the halogen atom and the phenyl nucleus, hydrocarbonoxy radicals and halohydrocarbonoxy radicals with at least 2 carbon atoms between the halogen atom and the phenyl nucleus, whereby these radicals do not represent any have tertiary alpha carbon atoms and n is an integer of at least about 50. The R and R groups preferably represent an alkyl hydrocarbon group having 1 to 8 carbon atoms, in particular a methyl group each. A known compound of this type is poly-2,6-dimethyl-1,4-phenylene ether.

Polyphenylene ethers can be used alone or in thermoplastic resin compositions can be used, e.g. the various copolymers, mixed polymers and blends of polyphenylene ethers obtained by copolymerizing or mixing the polyphenylene ethers be formed with other monomers or polymers, e.g. Polyolefins, Polystyrenes, polycarbonates and the like.

An important such thermoplastic resin composition includes a combination a polyphenylene ether resin and a styrene resin.

Such compositions, which have many desirable advantages of both the polyphenylene ethers and the styrene resins, are known from US Pat. No. 3,383,435. The most useful thermoplastic resin compositions of this type contain from about 5 to about 95, preferably from about 30 to 60 parts by weight of the polyphenylene ether and from about 95 to about 5, preferably from about 70 to about 40 parts by weight of the polystyrene resin. The styrene resin should generally contain at least 25% by weight of recurring units of a monomer of the formula II in which R is a hydrogen atom, a (lower) alkyl group or a halogen atom, Z is a vinyl group, a halogen atom or a (lower) alkyl group, and p represents 0 or an integer from 1 to 5. This group of resins includes homopolystyrene and polychlorostyrene and rubber modified polystyrenes and styrene / acrylonitrile copolymers, styrene / acrylonitrile / alpha-alkylstyrene terpolymers, styrene / acrylonitrile / butadiene terpolymers, poly-alpha-methylstyrene and copolymers of ethylvinylbenzene, divinylbenzene, and the like .

Among them, the most useful compositions are those in which the polystyrene resin component either homopolystyrene or one modified with rubber (blended or grafted) High impact polystyrene ', the rubber being e.g. polybutadiene, polyisoprene or a rubbery copolymer of butadiene and styrene.

It is known to use polyphenylene ether resins alone and in combination with polystyrene resins under the influence of heat and light, especially in oxygen-containing Atmospheres, are somewhat unstable. This instability causes thermoplastic Resin compositions containing a normally unstable polyphenylene ether component and also the polystyrene resin component will turn dark in color when extruded and molded and become brittle when heated; they become unusable for many purposes. The appearance of color, for example, severely restricts the production of white and pastel colors Tones with such masses.

Many different systems for stabilization have been proposed Using such masses against heat and light, however, is not entirely satisfactory. For example, phenolic antioxidants such as p-phenylphenol, N-stearyl-p-aminophenol and 2,2'-methylenebis-4-ethyl-6-tert-butylphenol as heat and light stabilizers has been used for polyphenylene ether compositions.

These stabilizers are generally effective even with brief exposure to heat been unsatisfactory. Other stabilizers too, such as ketenes and benzoic anhydride and mercaptobenzimidazoles have been suggested; it was found that they are effective with short exposure to heat, but not with relatively long exposure, which occur in many technical uses. Furthermore, the use of Phosphites such as tridecyl phosphite have been suggested. Although that's a right one If satisfactory mass is achieved, the color is not yet light when extruded enough to get slightly white or pastel tones. The increase in the amount of phosphite causes deterioration in physical properties Blends still exhibit a yellow color that was believed to be the polyphenylene ether resin component inherent.

To the inability of phosphite, a highest degree of initial whiteness at concentrations that match the physical properties does not affect, in addition, the phosphite alone in extending the heat aging time (heat againg time) does not give the impression that the optimum value has been reached will.

Based on the invention it was found that when adding certain Tin mercaptides or metal hypophosphites to form phosphites stabilizing systems with very high efficiency can be obtained. In particular, such new stabilizers lead in Kombinati.on with a thermoplastic resin with a polyphenylene ether component and a polystyrene resin component into a mass that has much greater stability against heat and light (e.g. due to an unexpectedly improved initial whiteness and an extension of the time until it becomes brittle by at least 100 percent) as a comparative polyphenylene ether / polystyrene mass, which only the Contains phosphite component of the known stabilizer. In addition to improvement the initial whiteness and the retention of flexibility can be done with Such masses achieve economic advantages with the known stabilization systems are not possible. Furthermore, the tin mercaptide or the metal hypophosphite appear to cooperate with the phosphite to achieve a much greater stabilizing effect, than can be expected from the small amounts added. According to the invention stabilized masses provided, which a larger amount - a thermoplastic Resin composition with a normally unstable polyphenylene ether component and with a polystyrene resin component and a stabilizing amount of a stabilizer contain a phosphite and (1) a tin mercaptide or (2) a metal hypophosphite in amounts from a small amount to an equivalent weight on the phosphite.

The phosphite compounds used as a component in the most of the stabilizing compositions listed above can be used vary widely and include both organic and inorganic Phosphite compounds.

However, examples of the most useful compounds are organic phosphites, for example compounds of formula III in which R³, R4 and R5 independently of one another are hydrogen atoms, halogen atoms, for example chlorine or bromine atoms, hydrocarbon radicals of 1 to 25 carbon atoms, for example saturated and unsaturated, straight-chain and branched-chain alkyl, cycloalkyl, mono- and dicarbocyclic aryl, aryl-substituted alkyl and represent alkyl-substituted aryl radicals, provided that at least one, but preferably two and in particular three of the R³, R4 - and R radicals represent something other than hydrogen atoms or halogen atoms.

Among the phosphites that can be used according to the invention, therefore include: phenyldodecyl phosphite, phenyl neopentyl phosphite, phenylethylene hydrogen phosphite, Triethylene phosphite, dichloroethyl phosphite, tributyl phosphite, trilauryl phosphite, bis-2-ethylhexyl hydrogen phosphite, Phenylbis-3,5,5t-trimethylhexyl phosphite, mixed 2-ethylhexyloctylphenyl phosphite, cis-9-octadecenyldiphenylphosphite) 2-ethylhexyldi-p-tolylphosphite, allylphenyl hydrogen phosphite, Bis-2-ethylhexyl ptolyl phosphite, triisooctyl phosphite, tridecyl phosphite, bis-2-ethylhexylphenyl phosphite, Triallyl phosphite, trimethallyl phosphite, trinonylphenyl phosphite, phenylmethyl hydrogen phosphite, Bis-p-tert-butylphenyloctadecyl phosphite triamyl phosphite, p-tert-butylphenyldioctadecyl phosphite, Diisopropyl hydrogen phosphite, p-cumyl dioctyl phosphite, di-n-propyl hydrogen phosphite Didodecyl-p-tolylphosphite Decylbis-p-1'1,3,3-tetrametfijlbutylphenylphosphit, Trimethyl phosphite, nonylbis-p-1,1,3,3-tetramethylphenyl phosphite, diallyl hydrogen phosphite, Diisodecyl ptolyl phosphite, Tricresyl phosphite, diisodecylphenyl phosphite, Triphenyl phosphite, octylbis-3,5,5'-trimethylhexyl phosphite, dibutylphenyl phosphite, Di-p-talyl-3,5,5-trimethylhexyl phosphite, 2-chloroethyldiphenyl phosphite, p-tolylbis-2,5,5-trimethylhexyl phosphite, Diphenyldecylphosphite, 2-ethylhexyldiphenylphosphite, tris-2-ethylhexylphosphite, Trioctadecyl phosphite, trioctyl phosphite, tris-2-chloroisopropyl phosphite, dibutyl hydrogen phosphite, Didodecyl hydrogen phosphite, phenyl didecyl phosphite, ditridecyl hydrogen phosphite, diphenyl hydrogen phosphite and the same. Preferred phosphites are tridecyl phosphite and triisooctyl phosphite represent.

According to a preferred embodiment of the invention, masses with a larger amount of a thermoplastic resin composition with a normally unstable polyphenylene ether component and with a polystyrene resin component and a stabilizing amount of a stabilizer provided, which is a phosphite, e.g. of Formula III above, and a tin mercaptide in an amount of one smaller portion up to about the same weight, soaked on the phosphite, includes.

The nature of the tin mercaptide is not particularly critical.

In general, any compound can be used as long as it is the bond 8th.

where R represents any organic radical, e.g. substituted or unsubstituted alkyl or aryl radical. Preferably the remaining valences of tin in the above sub-formula either with other Mercaptide residues R5S or saturated with organic residues.

Suitable organotin mercaptides belong to the group of formula IV in which n can assume a value from 1 to 3 and R5 represents an alkyl or aryl group having 1 to 25 carbon atoms, namely unsubstituted or substituted with, for example

Halogen atoms, hydroxy, alkoxy and carbalkoxy groups and the like and preferably with n-butyl or n-octyl groups, and R7 is an alkyl or aryl group having 1 to 25 carbon atoms, preferably 6 to 24 carbon atoms, or one Alkyl group with 1 to 6 carbon atoms, substituted by hydrogen atoms, Hydroxy, alkoxy or carbalkoxy groups and the like, preferably an alkyl group with one carbon atom represented by carbalkoxy groups with 5 to 9 carbon atoms is substituted. Examples of the preferred organotin mercaptides according to the above Formula are dibutyltin bislauryl mercaptide, which is produced, for example, by reacting dibutyltin dichloride with lauryl mercaptan or one of its salts and is commercially available is, dioctyltin bislauryl mercaptide, di-n-butyltin-S, S-bisisooctylthioglycolate, Di-noctyltin-S, S-bisisooctylthioglycolate, dibutyltin-ß-mercaptopropionate, and Di-n-octyltin-ß-mercaptopropionate. These are or can be commercially available be prepared in a known manner, e.g. by reacting dialkyltin oxide or dialkyl tin dichloride with a reactive derivative of the appropriate mercaptan. For use in bulk according to the invention, dibutyltin bislauryl mercaptide is used particularly preferred.

According to a preferred embodiment of the invention Masses with a greater amount of a thermoplastic harness mass with one normally unstable polyphenylene ether component and a polystyrene resin component and a1 stabilizing amount of a stabilizer provided, which is a phosphite, e.g. Formula III above, and a metal hypophosphite in an amount of a smaller one Share up to approximately the same weight, based on the phosphite, includes.

The type of metal hypophosphite is not particularly critical.

In general, any such compound can be used.

For example, metal hypophosphites of the formula V M (H2PO2) a (V) are suitable, in which M is a metal ion and a is an integer representing the valence of M corresponds to. Particularly suitable metal ions are those of metals of the group Ia, IIa, IIb, IVb, Vb, VIb, VIIb and VIII of the Periodic Table of the Elements. That Hypophosphite can e.g. lithium hypophosphite, sodium hypophosphite, potassium hypophosphite, Magnesium hypophosphite, calcium hypophosphite, zinc hypophosphite, titanium hypophosphite, Vanadium hypophosphite, molybdenum hypophosphite, manganese hypophosphite or cobalt hypophosphite and the like. Preferably, M in formula V is an ion of an alkali metal or of an alkaline earth metal or of manganese. For use as a metal hypophosphite in masses according to the invention are sodium hypophosphite, magnesium hypophosphite, Calcium hypophosphite or manganese hypophosphite is particularly preferred. In particular, be Sodium hypophosphite and magnesium hypophosphite are preferred.

The total amount of stabilizer added, i.e. phosphite and of Ennmercaptids or metal hypophosphite, depends on its activity and the The quality of the resin to be stabilized and the conditions under which the resin compound is subjected should be subjected.

The total stabilizer can be in an amount from about 0.1 to about 10 parts by weight per 100 parts by weight of the resin composition, and preferably in an amount of 1.0 to 8.0 parts by weight per 100 parts by weight of the resin composition are added.

Regarding the amounts of tin mercaptide or metal hypophosphite In general, the useful and preferred ranges of amounts are in the above specified area. The phosphite should be added in an amount that is at least corresponds to the remaining components in the stabilizer combination, preferably in an amount that is at least 1.5 times the remaining ingredients in the stabilizer portion the Mass corresponds. In other words, the tin mercaptide or the metal hypophosphite should be used make up a smaller proportion of up to about the same weight, based on the phosphite.

In preferred embodiments, the tin mercaptide or

Metal hypophosphite about 0.01 to about 5 parts by weight per 100 parts by weight the resin mass. In the most preferred case the tin mercaptide makes about 0.5 up to about 1.5 parts by weight per 100 parts by weight of the resin composition. Im particularly preferred Case makes the metal hypophosphite about 0.05 to about 0.2 parts by weight per 100 parts by weight the resin mass.

The way of adding the stabilizer to the thermoplastic resin composition with a content of polyphenylene ether component is not critical according to the invention. Therefore, any convenient procedure can be used, e.g. Stabilizer compound with the powdered thermoplastic resin compound in a mixer, e.g. a mixer of the Waring type. Alternatively, the resin can be used in one suitable solvent are dissolved and the stabilizer added to the solution. Thereafter, the stabilized mass can e.g. by precipitation or evaporation of the solvent In another way of working, a premix of the Components of the resinous mass produced, extruded the premix and the extruded strands cut into pellets.

The stabilized masses according to the invention are for all purposes useful for the polyphenylene ether compositions heretofore used; compare See, for example, U.S. Patents 3,306,874, 3,306,875 and 3,383,435 referenced above stabilized masses can be used, for example, to produce films, fibers and shaped objects usual working methods.

The invention is explained in more detail below with the aid of examples. If parts are given for quantities, they are parts by weight.

Example 1 50 parts of powdered poly-2,6-dimethyl-1,4-phenylene ether were obtained (General Electric Company, PPO, made according to U.S. Patents 3,306,874 and 3,306,875, Intrinsic viscosity 0.52 dl / g, measured in chloroform at 300C), with 50 Parts of granular, rubber-modified polystyrene of high impact resistance (Cosden Company 825 TV, containing approximately 9% by weight of polystyrene-grafted polybutadiene rubber), 5 parts of hexabromobenzene (fire inhibitor), 2 parts of antimony oxide (Synergeticum for the fire inhibitor), 1.5 parts polyethylene - (U.S. Industrial Chemicals, Microthene 710), 1.0 part of titanium dioxide (pigment), 1.0 part of triphenyl phosphate (fire inhibitor plasticizer), 1.0 part of tridecyl phosphite (stabilizer) and 1.0 part of dibutyltin bislauryl mercaptide (Advance Division, Carlisle Chemical Works, Advastab TM-918). After Extrusion at 304 to 31600 (580 to 6000F) became a light cream colored product according to the invention.

For comparison purposes, the procedure of this example was repeated, the 'dibutyltin bislauryl mercaptide being omitted. It turned gray Obtained product suitable for use in obtaining white and pastel colors molded objects was not suitable.

The procedure of this example was repeated, with instead of the mass of polyphenylene ether / polystyrene resin (50/50) a mass with a content of 20 parts of poly-2,6-dimethyl-1,4-phenylene ether and 80 parts modified with rubber High impact polystyrene was used. Essentially they became the same Get results.

Stabilized masses according to the invention were also obtained, when adding 20, 30 and 40 parts of glass fiber reinforcement to the formulation of this example and if hexachlorobenzene or highly chlorinated instead of hexabromobenzene Biphenyl (Monsanto Company Arochlor 1268) was used. Further stabilized masses were obtained according to the invention, if instead of with Rubber modified polystyrene high impact resistance homopolystyrenes are used became.

Examples 2 to 5 A standard 450 parts powdered formulation was used Poly-2,6-dimethyl-1,4-phenylene ether (prepared according to the procedure of the above cited U.S. Patents 3,306,874 and 3,306,875, intrinsic viscosity 0.52 dl / g, measured in chloroform at 300C), 550 parts of polystyrene modified with rubber high impact strength (Cosden Corp. 825 TV, with a content of about 9% by weight with polystyrene grafted polybutadiene rubber), 18 g micronized polyethylene (U.S. Industrial Chemicals M-710), 10.0 grams of titanium dioxide and 2.5 grams of N, N-distearoyl ethylenediamine (Acrawax C). Triisodecyl phosphite was added to this standard mixture and various amounts of magnesium hypophosphite were added. The approaches were mixed and massed by passing through a Wayne-type extruder (1.9 cm or 3/4 ") at a temperature of the form of 2380C (4600F) and at temperatures the front and back of the 2930C (5600F). The extruded Strands were chopped into pellets and then injection molded into thin tensile rods. These were used around the time to become brittle or break up to 12800in To measure 125 ° C air. The time to break was determined by the elongation of the Tensile bars at room temperature under tension in an Instron test machine Measured at different aging times until the specimen failed to break became longer or films were torn into fragments when partially folded.

In addition, plates molded from the mass have been considered with regard to the degree of yellowness according to standard methods on a colorimeter (IDL Kollmorgen "Coloreye", Model D-1) measured after aging at 128 ° C for periods of up to 309 hours. The higher the Yellowness Index at a given time, the less is the mass is suitable for use on light pastel-colored objects.

The approaches, times to break and the yellowness indices are in the following table 1 compiled.

TABLE 1 Compositions of polyphenylene ethers and polystyrene resins which Stabilized with phosphite and magnesium hypophosphite are time to beginning Fractional index ** game weight parts (h) ** degree of yellowing 309 h 2-C-1 poly-2,6-dimethyl-1,4-phenylene ether 450 Polystyrene modified with rubber (control - no phosphite) 550 66 0.37 0.81 2-C-2 poly-2,6-dimethyl-1,4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite (control - no hypophosphite) 10 168 0.29 0.81 2 poly-2,6-dimethyl-1, 4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite 10 Magnesium hypophosphite 2 264 0.25 0.76 3 poly-2,6-dimethyl-1,4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite 10 magnesium hypophosphite 4> 309 0.21 0.77 4 Poly-2,6-dimethyl-1,4-phenylene ether 450 modified with rubber Polystyrene 550 TABLE 1 (cont.) Time to start-at-X to break licher index game mass * parts (h) ** yellowness 309. h triisooctyl phosphite 10 magnesium hypophosphite 8 309 Q, 16 0.68 5 poly-2,6-dimethyl-1,4-phenylene ether 450 modified with rubber Polystyrene 550 triisooctyl phosphite 10 magnesium hypophosphite 12 264 0.18 0.69 -t- furthermore each with a content of 15 parts of polyethylene, 10 parts of titanium oxide and 2.5 parts of N, N-distearoylethylenediamine ** - at 125 ° C.

The table above shows that a remarkable Improvement of the resistance to breakage is achieved according to the invention, when magnesium hypophosphite is added to the mass. Furthermore, the initial Yellowness noticeably reduced. Also, the yellowing with aging became considerable delayed. It should be noted that when the amount of hypophosphite is the phosphite weight to, exceeding begins to decline the desired resistance to breakage begins to become and the yellowing becomes stronger.

Examples 6 to 9 The one used in Examples 2 to 5 was used Repeat the procedure, using instead of magnesium hypophosphite Sodium hypophosphite was used.

The approaches, times to break and the yellowness indices are in the following table 2 compiled.

TABLE 2 Compositions of polyphenylene ethers and polystyrene resins which stabilized with phosphite and sodium hypophosphite are neiz D1S anrang-accessories Fractional index ** game mass * parts (h) ** degree of yellowing 309 h 2-C-1 poly-2,6-dimethyl-1,4-phenylene ether 450 rubber modified polystyrene (control - no phosphite) 550 66 0.37 0.81 2-C-2 poly-2,6-dimethyl-1,4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite (control - no hypophosphite) 10 168 0.29 0.81 6 poly-2,6-dimethyl-1,4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite 10 sodium hypophosphite 2> 309 0.20 0.67 7 Poly-2,6-dimethyl-1,4-phenylene ether 450 modified with rubber Polystyrene 550 triphenyl phosphite 10 sodium hypophosphite 4,288 0.18-0.62 TABEL 2 (cont.) Time to start-example for fractional index backlash Dimensions * parts (h) * 6 Yellowness -309-h 8 Poly-2,6-dimethyl-1,4-phenylene ether 450 modified with rubber Polystyrene 550 triisooctyl phosphite 10 sodium hypophosphite 8 309 0.19 0.59 9 poly-2,6-dimethyl-1, 4-phenylene ether 450 rubber modified polystyrene 550 triisooctyl phosphite 10 Sodium hypophosphite 12 288 0.15 0.55 * - furthermore each with a content of 15 Parts of polyethylene, 10 parts of thandioxide and 2.5 parts of N, N-distearoylethylenediamine ** - at 125 ° C.

It can be seen that sodium hypophosphite greatly enhances stability and durability of the whiteness of the composition according to the invention in comparison with the control samples.

Examples 9 to 13 The procedure of Example 2 was repeated, the amount of 0.2 parts of magnesium hypophosphite per 100 parts of resin being as follows was replaced: Example Additive 10 0.2 parts calcium hypophosphite 11 0.1 part magnesium hypophosphite 12 0.05 part magnesium hypophosphite and 13 0.2 Parts of manganese hypophosphite per 100 parts of resin.

There were masses according to the invention with significantly improved initial whiteness obtained. The improved initial whiteness was at Maintain hot air aging at 1000C. An adverse effect on the physical Properties did not occur.

The above procedures were repeated, wherein instead of tridecyl phosphite and triisooctyl phosphite, the following compounds are used were: phenyldidodecyl phosphite, triamyl phosphite, dibutylphenyl phosphite, trioctadecyl phosphite.

Stabilized compositions according to the invention were obtained.

The procedures described above were repeated, wherein instead of poly-2,6-dimethyl-1,4-phenylene ether, the following compounds are used were: 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 (2,6-diphenyl-1,4-phenylene) ethers.

Stabilized compositions according to the invention were obtained.

The above procedures were repeated, wherein instead of poly (2,6-dimethyl-1,4-phenylene) ether, the following thermoplastics Resin masses (US Pat. No. 3,383,435) were used: mass parts poly (2,6-dimethyl-1,4-phenylene) ether 50 homopolystyrene 50 poly (2,6-dimethyl-1,4-phenylene) ether 50 poly (alpha-methylstyrene) 50 Poly- (2,6-dimethyl-1,4-phenylene) ether 50 styrene-acrylonitrile copolymer (27 % ACN) 50 Stabilized compositions according to the invention were obtained.

There are also other embodiments and modifications according to FIG Invention possible within the framework of the above disclosure.

The masses can also contain various fillers, reinforcing agents, i.e., glass fibers, modifiers, dyes, pigments, plasticizers, and the like contain.

Claims (15)

Claims 1. Stabilized mass containing a large amount of a thermoplastic Resin composition having a generally unstable polyphenylene ether component and a Polystyrene resin component, not shown with a content of 0.1 to 10 parts by weight per 100 parts by weight of the resin composition of a stabilizer which a phosphite and in an amount from a smaller proportion to the same weight, based on the phosphite, (1) a tin mercaptide or (2) a metal hypophosphite contains. 2. Composition according to claim 1, characterized by a polyphenylene ether of the formula in which R and R1 are monovalent substituents from the group consisting of hydrogen atom, halogen atom, hydrocarbon radicals, halogenated hydrocarbon radicals with at least 2 carbon atoms between the halogen atom and the phenyl nucleus, hydrocarbonoxy radicals and halohydrocarbonoxy radicals with at least 2 carbon atoms between the halogen atom and the phenyl nucleus, the radicals not being tertiary alpha- Contain carbon atoms and n is an integer of at least about 50. 3. Composition according to claim 2, d a d u r c h g e k e n n -z e i c h n e t that R and R each represent methyl groups. 4. Composition according to one of the preceding claims, d a d u r c h g Note that the thermoplastic resin composition is about 5 to about 95 parts by weight of polyphenylene ether and about 95 to about 5 parts by weight of polystyrene resin contains. 5. Composition according to one of the preceding claims, characterized by a polystyrene resin in which at least 25% by weight of its repeating units are from a monomer of the formula in which R represents a hydrogen atom, a (lower) alkyl group or a halogen atom, Z is a vinyl group, a halogen atom or a (lower) alkyl group, and p represents 0 or an integer from 1 to 5. 6. Composition according to claim 5, d a d u r c h g e k e n n -z e i c h n e t that the polystyrene resin is homopolystyrene. 7. Composition according to claim 5, d a d u r c h g e k e n n -z e i c h ne t that the polystyrene resin is a rubber modified polystyrene of high impact resistance is. 8. Composition according to one of the preceding claims, d a d u r c h g It is not noted that they contain the tin mercaptide or the metal hypophosphite in an amount of about 0.01 to about 5 parts by weight per 100 parts by weight of the resin composition contains. 9. Composition according to one of the preceding claims, d a d u r c h g It is not noted that it contains an organic phosphite as the phosphite. 10. Composition according to claim 9, d a d u r c h g e k e n n -z e i c h n e t that it contains tridecyl phosphite or triisooctyl phosphite as phosphite. 11. Composition according to one of the preceding claims, d a d u r c h g It is not noted that it contains an organotin mercaptide as tin mercaptide. 12. Composition according to claim 11, d a d u r c h g e k e n n -z e i c h n e t that it contains dibutyltin bislauryl mercaptide as an organotin mercaptide. 13. Composition according to one of the preceding claims, d a d u r c h g It is not possible to state that it is a metal hypophosphite of the formula M (H2P02) a contains, in which M is an ion of a metal from groups Ia, IIa, IIb, IVb, Vb, VIb, VIIb or VIII of the Periodic Table of the Elements and a represents an integer corresponding to the valence of M. 14. Composition according to claim 13, d a d u r c h g e k e n n -z e i c h n e t that they are a metal hypophosphite's Formula according to claim 13 contains, in which M is an ion of an alkali metal, an alkaline earth metal or of Manganese represents 0 15. Composition according to claim 14, d a d u r c h g e k e n n -z e i c n e t that as metal hypophosphite they are sodium hypophosphite, magnesium hypophosphite, Contains calcium hypophosphite or manganese hypophosphite.