JPS5952668B2 - Odorless resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an odorless resin composition with excellent impact resistance.

Vinyl aromatic hydrocarbon polymers, such as polystyrene, are colorless and transparent and can be easily molded and processed, and have good compatibility with various dyes and pigments, so they are colored and used for various purposes. It has the disadvantage of being inferior in quality.

Methods to improve this problem include making a block copolymer of conjugated diolefin and styrene, mechanically mixing a conjugated diolefin polymer or a block copolymer of conjugated diolefin and styrene with polystyrene, or Methods such as bulk polymerization and bulk-suspension polymerization of a styrene solution of an olefin polymer or a copolymer of conjugated geo-refin and styrene are known. The polymer obtained by this method (hereinafter referred to as conjugated diolefin-containing vinyl aromatic hydrocarbon polymer) has significantly better impact resistance than vinyl aromatic hydrocarbon polymer homopolymer. Sheets and films produced by extrusion molding methods, as well as various containers and packages made by thermoforming them using vacuum, compressed air, etc.
Alternatively, it is applied to a wide range of uses such as toys, daily necessities, miscellaneous goods, and light electrical parts by injection molding, blow molding, etc.
However, on the other hand, vinyl aromatic hydrocarbon polymers containing conjugated diolefins are unstable to heat and oxygen due to unsaturated bonds in the polymer, and degrade due to heat and mechanical shearing force during processing. As a result, mechanical strength and impact resistance were significantly reduced, and in some cases, the product became discolored, resulting in drawbacks that diminished its commercial value.

In order to improve the drawbacks of the conjugated diolefin-containing vinyl aromatic hydrocarbon polymer, various stabilizers have been developed in the past, and some have relatively satisfactory effects. However, conventional stabilizers can effectively prevent decreases in mechanical strength, impact resistance, and discoloration caused by polymer deterioration due to heat and mechanical shearing forces during processing processes, and trace amounts of polymer deterioration. In addition, little consideration has been given to the odor of the added stabilizer itself and the unpleasant odor caused by chemical and physical changes in the stabilizer. Therefore, molded products subjected to harsh conditions such as extrusion molding and injection molding generate unpleasant odors due to chemical and physical changes in the polymer and stabilizer, and such molded products are particularly susceptible to food consumption. In the case of direct contact, the odor transfers to the food and impairs the flavor of the food, resulting in problems such as a significant reduction in the commercial value of the polymer. The inventors of the present invention have conducted extensive research and intensive studies in order to improve the above-mentioned drawbacks of conjugated diene-containing vinyl aromatic hydrocarbon polymers, and have found that by using several specific stabilizers in combination, It has been found that a resin composition with excellent impact resistance and low odor can be obtained. That is, the present invention contains a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer or a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer having a conjugated diolefin content of 5 to 40% by weight. The total conjugated diolefin content is 5 to 40% by weight. The polymer mixture contains a stabilizer consisting of (1) and () or a stabilizer consisting of (1), (1) and (self) from the following stabilizer group, and (1) and An object of the present invention is to obtain an odorless resin composition containing at least 0.1 part by weight of () per 100 parts by weight of the block copolymer or the polymer mixture. (1) Tris(nonylphenyl)phosphite.

() n-octadecyl-β-(4″-hydroxy-3
″,5″-di-t-butyl phenyl) propionate or 4,4″-thiobis-(6-t-butylmetacresol) or mixtures thereof, or these and 2,6-di-t-butyl-4-methylphenol (auto) dilaurylthiodipropionate or laurylstearylthiodipropionate or mixtures thereof.

Among the conjugated diolefin-vinyl aromatic hydrocarbon block copolymers used in the present invention, a method for producing a block copolymer having a relatively high vinyl aromatic hydrocarbon content is described in Japanese Patent Publication No. 47-3252. Publication No. 48-2423, etc., and Japanese Patent Application Laid-open No. 51-33184 by the present applicant.
There is a patent application No. 50-27094.

All of these methods involve block copolymerization of a conjugated diolefin monomer and a styrene monomer using an anionic polymerization initiator such as alkyl lithium in a hydrocarbon solvent.
By these methods, general formula (A-B).

In A, a linear block represented by B-A)1B+A-B)n (wherein A is a styrene polymer block, B is a conjugated diolefin polymer block, and n is an integer from 1 to 5) Polymer or general formula (wherein A and B are the same as above, C represents a coupling agent, and n is 1 to 5.

) is obtained as a radial block copolymer.

Furthermore, it may be produced as a mixture of block copolymers of the above general formula or a mixture of block copolymers and styrene polymers. The polymer mixture containing the conjugated diolefin-vinyl aromatic hydrocarbon block copolymer used in the present invention is a linear block copolymer or a radial block copolymer represented by the following general formula, and a polystyrene block copolymer. polymers, polyethylene polymers, polypropylene polymers, polybutene polymers, vinyl chloride polymers, vinyl acetate polymers, polyamide polymers, polyester polymers, polyacrylate polymers, phenoxy polymers It is a mixture with a thermoplastic polymer such as a polybutadiene polymer. (In the formula, A is a vinyl aromatic hydrocarbon polymer block, B is a conjugated diolefin copolymer block, C is a coupling agent, and n is 1
It is an integer of ~5.

) As the block copolymer, it is generally preferable to have a vinyl aromatic hydrocarbon content of 10 to 90% by weight and a conjugated diolefin content of 90 to 10% by weight. No. 36-19286, Special Publication No. 1973
There is No.-17979.

In the present invention, among the thermoplastic polymers used in the polymer mixture containing the conjugated diolefin-vinyl aromatic hydrocarbon block copolymer, polystyrene-based polymers include polystyrene, impact-resistant rubber-modified styrene, and acrylonitrile. Examples include a butadiene-styrene copolymer, an acrylic acid ester butadiene-styrene copolymer, a methacrylic acid ester-butadiene-styrene copolymer, and a blend of these polymers.

Examples of polyethylene polymers include ethylene homopolymer,
Ethylene containing 50% or more of ethylene. Copolymers of this and other monomers that can be copolymerized, such as ethylene/vinyl acetate copolymer, ethylene/vinyl chloride copolymer, ethylene/styrene copolymer, ethylene/ethyl acrylate copolymer , ethylene-propylene copolymer, etc., ethylene and a. Ethylene/acrylic acid ionomer, which is a copolymer of acrylic acid with a metal salt such as sodium or potassium, or an ethylene homopolymer substituted or added with another atom or atomic group at any position, for example, chlorinated Polyethylene etc. are used.

Examples of polypropylene polymers include propylene homopolymers, copolymers of pukapylene containing 50% or more of propylene and other monomers copolymerizable with it, such as propylene/vinyl chloride copolymers, propylene/vinyl chloride copolymers, etc. Styrene copolymers, propylene/ethyl acrylate copolymers, propylene/vinyl acetate copolymers, etc., made by substituting or adding other atoms or atomic groups to any position of a propylene homopolymer, such as chlorinated polypropylene etc. are used. Examples of the polybutene-based polymer include a butene-1 homopolymer, a copolymer of butene-1 and another monomer copolymerizable with it, and a butene-1 homopolymer containing other monomers at any position. There are polybutene-based polymers made by substituting or adding atoms or atomic groups.

Examples of vinyl chloride-based polymers include polyvinyl chloride, polyvinylidene chloride, and copolymers of vinyl chloride containing 50% or more of vinyl chloride and other monomers copolymerizable with it, such as vinyl chloride/acetic acid. Vinyl copolymer, vinyl chloride/ethylene copolymer, vinyl chloride/propylene copolymer, vinyl chloride/isobutylene copolymer, vinyl chloride/vinylidene chloride copolymer, vinyl chloride/styrene/maleic anhydride ternary copolymer Coalescence, vinyl chloride/styrene/acrylonitrile copolymer, vinyl chloride monovinylidene chloride/vinyl acetate terpolymer, vinyl chloride/acrylic ester copolymer, vinyl chloride/maleic ester copolymer, vinyl chloride/methacrylic Acid ester copolymers, vinyl chloride/acrylonitrile copolymers, etc. are used. In addition, as the polybutadiene polymer, in addition to trans polybutadiene, 1,2-polybutadiene, and partially hydrogenated 1,2-polybutadiene, modified liquid polybutadiene such as maleic anhydride-modified liquid polybutadiene and epoxidized liquid polybutadiene can be used. . In the present invention, preferred thermoplastic polymers to be mixed with the conjugated diolefin-vinyl aromatic hydrocarbon block copolymer are polystyrene, impact-resistant rubber-modified styrene copolymers, and mixtures thereof.

The impact-resistant rubber-modified styrene polymer is generally called impact-resistant polystyrene or high-impact polystyrene, and is made by dissolving 5 to 20% by weight of polybutadiene rubber or styrene-butadiene copolymer rubber in styrene monomer. It is manufactured by polymerizing it by emulsion polymerization, bulk polymerization, or bulk suspension polymerization, and any commercially available products may be used. The conjugated diolefin content of the conjugated diolefin-vinyl aromatic hydrocarbon block copolymer and the polymer mixture containing the block copolymer used in the present invention is from 5 to 40% by weight.

When the conjugated diolefin content is less than the above range,
Impact resistance is poor, which is undesirable, and when the amount exceeds the above range, hardness and strength are poor, which is not desirable. Note that 1,3-butadiene and isoprene are generally often used as the conjugated diolefin. The specific stabilizer used in the present invention is a stabilizer composed of (1) and (1) from the above stabilizer group, or a stabilizer composed of (1), (), and (self). , (1) and (1) are each 0.1 parts by weight per 100 parts by weight of the conjugated diolefin-vinyl aromatic hydrocarbon block copolymer or the polymer mixture containing the block copolymer. Used in proportions of parts by weight or more.

If the amount of any of the constituent components () and () added is not 0.1 part by weight or more, the reduction in mechanical strength and coloration due to polymer deterioration may be improved, but the odor will not be improved. is very small. On the other hand, in the present invention, increasing the amount of each component added improves the odor of the polymer, but if the amount is too large, the stabilizer itself may bleed onto the surface of the molded product or transfer to food. Therefore, problems such as spoiling the flavor of the food arise. Therefore, the total amount of stabilizers used in the present invention is preferably 2 parts by weight or less. The stabilizer used in the present invention may be incorporated into the conjugated diolefin vinyl aromatic hydrocarbon block copolymer or the polymer mixture containing the block copolymer using any method suitable for producing a uniform composition. method can be applied. For example, it may be added to a polymer solution after the completion of polymerization of polystyrene-based polymers, or it may be added directly to polymer powder or particles, etc., and mixed using a roll, extruder, etc. A method of mixing additives can be applied. Further, the stabilizer used in the present invention may be added in several portions. That is, after adding a portion of the stabilizer to the polymer solution, the remaining stabilizer is added to the polymer powder or particles obtained by recovering it using a normal finishing method, and the mixture is uniformly mixed using an extruder, etc. You can also. The order of addition of the stabilizers used in the present invention is not particularly limited, but
When adding the stabilizer of the present invention to a polymer mixture containing a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer, after adding the entire amount of the stabilizer to the block copolymer, the polystyrene It is preferable to mix it with a thermoplastic polymer such as an impact-resistant rubber-modified styrene polymer from the viewpoint of odor prevention effect.

The method of adding the stabilizer to the PROTSUKU copolymer may be as follows:
After adding a portion of the stabilizer to the polymerization solution, the remaining stabilizer may be simply dry-blended or dry-blended with the protox copolymer powder or particles obtained by recovery using conventional finishing methods. The mixture may be kneaded using an extruder or the like. Although the particular stabilizers used in the present invention are particularly effective in preventing odor in conjugated diolefin-vinyl aromatic hydrocarbon block copolymers and polymer mixtures containing the block copolymers, other conjugated diolefin-vinyl aromatic hydrocarbon block copolymers are It can also be applied to odor prevention for multilayer composite films or sheets using reflex vinyl aromatic hydrocarbon block copolymers.

Such a multilayer composite film or sheet may include a film or sheet of a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer and the above-mentioned thermoplastic polymer, such as a polystyrene polymer, a polyethylene polymer,
It is a combination of films or sheets of polypropylene polymers, vinyl chloride polymers, polyester polymers, etc., or metal foils, and can be formed into various multilayer composite films or sheets with two or more layers depending on the order of combination. can give. Such a multilayer composite film or sheet is generally produced by a method in which a film or sheet of the thermoplastic polymer, or a metal foil or the like is coated with a solution of a PROK copolymer containing the stabilizer of the present invention. It is manufactured by bonding films or sheets together with an adhesive or by melt-extrusion laminating a block copolymer. The resin composition in the present invention may contain a small amount of lubricant depending on the purpose of use.
Additives such as fillers, blowing agents and blowing aids, antifogging agents, antimicrobials, fungicides, colorants, and the like can be included. For example, as a lubricant, synthetic paraffin, liquid paraffin, industrial white mineral oil, petroleum wax, polyethylene wax, micro wax, higher fatty acids having 8 to 22 carbon atoms, oxyfatty acids, higher fatty acids having 12 to 22 carbon atoms, Amides and bisamides, alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, ester vats, linear saturated aliphatic monohydric alcohols having 8 to 18 carbon atoms, polyhydric alcohols, esters and partial esters of fatty acids and polyhydric alcohols esters, partial esters of fatty acids and polyglycols and polyglycerols, silicone oils, or mixtures thereof can be used. Examples of fillers include oxides, hydroxides, carbonate compounds, chlorides, sulfuric compounds, silicic acid compounds, and other clays from Groups 1 to 1V of the periodic table.
Talc, metal powder, etc. can be used. As blowing agents and blowing aids, azodicarbonamide, sodium hydrogen carbonate, ammonium hydrogen carbonate, citric acid, tartaric acid, succinic acid, malic acid, aliphatic hydrocarbons of C7 or less, cycloalkanes, etc. can be used. Further, as the antifogging agent, any known antifogging agent can be used, such as fatty acids having 12 to 22 carbon atoms, natural animal and vegetable oils, polyhydric alcohol monoesters or diesters of mixed fatty acids obtained from these hydrogenated oils, substituted ethanolamines, etc. . As described above, by carrying out the present invention, it is possible to obtain a resin composition that is not only excellent in mechanical properties, impact resistance, and discoloration resistance, but also odorless.

The resin composition of the present invention having such characteristics is particularly suitable as a material for food containers and packaging, which are required to be odorless. EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to the Examples.

Examples 1 to 8, Comparative Examples 1 to 16 By the following method,
An A-B-A block copolymer having a styrene content of 75% by weight (A indicates a styrene polymer block, B indicates a butadiene polymer block) was produced.

Adding 0.15 parts of n-butyllithium as an active lithium compound to a dehydrated and degassed 15% by weight cyclohexane solution containing 75 parts by weight of styrene under a nitrogen atmosphere;
Polymerization was carried out at 70°C for 1 hour, and then a dehydrated and degassed 15% by weight cyclohexane solution containing 50 parts by weight of butadiene was added, and polymerization was carried out at 70°C for 1 hour. A dehydrated and degassed 15 wt % cyclohexane solution containing 75 wt % styrene was added and polymerized for 1 hour at 70° C., and then a small amount of methanol was added to stop the polymerization.

Then add 0.0% of tris(nonylphenyl)phosphite.
6 parts by weight was added. Next, a predetermined amount of this polymer solution was divided into small portions, each of the stabilizers shown in Table 1 was added to the polymer solution, and the solvent was removed by distillation under heating to isolate the copolymer. . The copolymer obtained as above was heated at 200°C and 150 rpm2 in a Brabender plastograph.
After kneading for 0 minutes, the coloring, odor, and impact strength retention of the copolymer compression molded plates before and after kneading were compared, and the results are shown in Table 1.

Next, a mixture of a B-A-B-A type block copolymer and polystyrene was prepared in the following manner and subjected to a thermal shear test.

That is, in a nitrogen atmosphere, 0.03 parts by weight of n-butyllithium as an active lithium compound was added to a 30% by weight n-hexane solution containing 10 parts by weight of dehydrated and degassed butadiene, and the mixture was heated to 1. A 30 wt% n-hexane solution containing 10 parts by weight of dehydrated and degassed styrene was polymerized for 1 hour, and a 30 wt% n-hexane solution containing 10 parts by weight of dehydrated and degassed styrene was polymerized for 1 hour, and a 30 wt% solution containing 10 parts by weight of butadiene that had been further dehydrated and degassed was added. Add n-hexane solution and polymerize at 70°C for 1 hour to obtain active B
-A-B type Protuta copolymer was obtained.

While maintaining the activity of the obtained block copolymer, a 30% by weight n-hexane solution containing 0.045 parts by weight of n-butyllithium as an active lithium compound and 70 parts by weight of dehydrated and degassed styrene was added. After polymerization at 70° C. for 2 hours, a small amount of methanol was added to stop the polymerization. Tris (
After adding 0.25 parts by weight of nonylphenyl) phosphorite and 0.25 parts by weight of dilauryl thiodipropionic acid ester, a predetermined amount of this polymer solution was divided into small portions, and the polymer solution was stabilized as shown in Table 2. each agent was added. Thereafter, the solvent was removed from each polymer solution by distillation under heating, and the polymer mixture was isolated. The polymer mixture thus obtained was subjected to a thermal shear test in the same manner as described above, and the results are shown in Table 2.

(Note 1) The abbreviations of stabilizers are as follows.

(1) AO-1; n-octadecyl-β-(4″-hydroxy-3″,5″-di-t-butylphenyl)propionate (2) AO-2; 4,4″-thiobis-(6 -t-butylmacresol) (3) AO-3; 2,2″-methylenebis(4-methyl-6-t-butylphenol) (4
)AO-4; 2,2″-methylenebis(4-ethyl-6
-t-butylphenol) (5) AO-5; Tris (2
-Methyl-4-hydroxy-5-t-butylphenylbutane) (6)AO-6;2-(2″hydroxy-5″-
methylphenyl)benzotriazole (7) BHT; 2
, 6-di-t-butyl-4-methylenolephenol (Note 2) The thermal shear test and evaluation method were as follows.

(1) Thermal shear test A polymer to which a prescribed stabilizer was added was kneaded using a Brabender blastograph.

The crosstalk conditions are as follows.

(2) (3) Hue The thermally sheared polymer was compression molded into a plate with a thickness of 3 m/m at 150°C, and its hue was determined visually.

Judgment criteria ◎; Colorless or white ○; Slightly yellow △; Yellow-brown ×; Brown impact strength retention rate The impact strength of the polymer before and after thermal shearing was measured according to JIS K687l, and the retention rates after thermal shearing were compared.

Judgment Criteria (4) The polymer after odor thermal shearing was heated to 150°C, with a length of 1.5 cm and a width of 15 cm.
After compression molding into a sheet with a thickness of 0.5 m/m and 1 cm in length and 1 cm in width, the pieces were placed in a 100 m Erlenmeyer flask with a stopper and heated at 60°C for 2 hours. was subjected to a sensory test.

In the sensory test method, a panel of 20 people smelled the odor of each sample and judged the strength of the odor based on the following evaluation rank.

Evaluation rank: 0 points; no odor, 1 point; faint odor, 2 points; odor, 3 points; fairly strong odor, 4 points; very strong odor.Then, the evaluation results of each sample were combined and the strength of the odor was compared.

As is clear from the results shown in Table 1 or Table 2 of the criteria, the PROTSUKU copolymer containing the stabilizer of the present invention and the polymer mixture of the PROTSUKU copolymer and polystyrene have excellent color resistance and impact resistance. Not only does it have excellent strength retention, it is also odorless, making it suitable as a resin material for food containers and packaging.

On the other hand, among the several stabilizers shown as comparative examples, none were superior in all of coloring resistance, impact strength retention, and odorlessness, which draws attention to the uniqueness of the present invention. Example 9
~11. Comparative Examples 17-18 B-A-B-A tapered type 4 block copolymers with a styrene content of 40% by weight were produced.

To the polymer solution, 2,6-di-t-butyl-4-methylphenol and trisnonylphenyl phosphorite were added in amounts of 0.7 and 0.0 parts per 100 parts by weight of the polymer, respectively.
After adding 3 parts by weight, the solvent was removed by distillation under heating, and the copolymer was isolated. Next, to the copolymer obtained above,
After dry blending various stabilizers and thermoplastic polymers according to the amounts shown in Table 3, a thermal shear test similar to that in Example 1 was conducted, and the odorlessness of the polymer after thermal shearing was sensory tested. .

As is clear from the results in Table 3, the stabilizer of the present invention:
Conjugated diolefin-vinyl aromatic hydrocarbon; has excellent odor-preventing effects in mixtures of basic block copolymers and various thermoplastic polymers.

Examples 12-14, Comparative Examples 19-21 Examples 5-8
A mixture of a B-A-B-A block copolymer produced in the same manner as described above and polystyrene. After dividing a predetermined amount of a polymer solution consisting of the compound, tris(nonylphenyl) phosphorite, dilaurylthiodipropionic acid ester, 2,6-di-t-butyl-4-methylphenol and n -Octadecyl-β-(4''-hydroxy-3'',5''-di-t-butylphenyl)propionate was added in the amounts shown in Table 4, respectively.

Thereafter, the solvent was removed by distillation under heating, and the polymer mixture was isolated. After adding 10% by weight of a commercially available impact-resistant rubber-modified styrene polymer (rubber content: approximately 5% by weight) to the obtained polymer mixture, a thermal shear test similar to that in Example 1 was conducted.
The results are shown in Table 4.

As can be seen from Table 4, among the stabilizers of the present invention, (1)
If the amount of any of the components (1) and (1) added is 0.1 part by weight or less, a resin composition excellent in color resistance, impact strength retention, and odorlessness cannot be obtained.

Examples 15 and 16 Styrene content 5 by the following method
A 0% by weight BA-B-A tapered type 4 block copolymer was prepared.

Under a nitrogen atmosphere, 0.1 part by weight of n-butyllithium as an active lithium compound was added to a 15% by weight solution of cyclohexane containing 25 parts by weight of dehydrated and degassed butadiene and 25 parts by weight of styrene. The polymerization was carried out at 70°C for 2 hours, and a 15% by weight cyclohexane solution containing 25 parts by weight of dehydrated and degassed butadiene and 25 parts by weight of styrene was added, and the polymerization was carried out at 70°C for 2 hours, after which a small amount of methanol was added. was added to stop the polymerization.

A portion of the obtained polymer solution contained 2,6-di-t-butyl-4-methylphenol, tris(nonylphenyl) phosphorite, n-otatadecyl-β-(4″-hydroxy 3″,5″-di (t-butylphenyl) fluoropionate at 1.0 and 0 parts by weight, respectively, per 100 parts by weight of the polymer.
．． After adding 5.2.5 parts by weight, the solvent was removed by distillation under heating, and the polymer was isolated. This block copolymer 20
80 parts by weight of commercially available polystyrene were mixed, and the same thermal shear test as in Example 1 was conducted. (Example 15)
On the other hand, the remaining polymer solution contains tris(nonylphenyl)
After adding 0.5 parts by weight of phosphorite to 100 parts by weight of the polymer, the solvent was removed by distillation under heating to isolate the polymer.

After mixing 80 parts by weight of commercially available polystyrene with 20 parts by weight of the obtained block copolymer, 1.0 parts by weight of 2,6-di-t-butylphenol was added to 100 parts by weight of the block copolymer. , n-octadecyl-β-(4″-hydroxy-3″,5″-di-t-butylphenyl) propionate per 100 parts by weight of the block copolymer.
After adding 5 parts by weight, the same thermal shear test as in Example 1 was conducted. (Example 16) The coloring resistance, impact strength retention, and odorlessness of the polymer mixtures after these thermal shear tests were compared, and the results are shown in Table 5.

As can be seen from Table 5, all of these polymer mixtures are excellent in color resistance, impact strength retention, and odorlessness. The polymer mixture obtained in this way was more excellent in odorlessness, and Examples 17 and 18, Comparative Example 22, Example 15,
B-A with a styrene content of 40% by weight in the same manner as No. 16
-B-A tapered type 4 block copolymer was prepared.

To the polymer solution, 2,6-di-t-butyl-4-methylphenol and trisnonylphenyl phosphorite were added at 0.7 and 0.3 parts by weight, respectively, per 100 parts by weight of the polymer.
After adding parts by weight, the solvent was removed by distillation under heating, and the copolymer was isolated. Next, the copolymer obtained above was dry-blended with various stabilizers and high-density polyethylene in the amounts shown in Table 6, and then subjected to a thermal shear test similar to Example 1. The odorlessness of the polymer after shearing was sensory tested.

As is clear from the results in Table 6, the stabilizer of the present invention is
A mixture of a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer and high-density polyethylene has an excellent odor-preventing effect.

Claims (1)

[Scope of Claims] 1 Contains a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer or a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer having a conjugated diolefin content of 5 to 40% by weight In a polymer mixture having a total conjugated diolefin content of 5 to 40% by weight, a stabilizer consisting of (I) and (II) from the following stabilizer group, or (I) and (II) and (III), and (I) and (II).
An odorless resin composition containing at least 0.1 part by weight of the block copolymer or the polymer mixture based on 100 parts by weight of the block copolymer or the polymer mixture. (I) Tris(nonylphenyl)phosphite. (II) n-octadecyl-β-(4'-hydroxy-3
',5'-di-t-butylphenyl)propionate or 4,4'-thiobis-(6-t-butymetacresol) or mixtures thereof, or 2,6-di-
Mixture with t-butyl-4-methylphenol. (III
) dilaurylthiodipropionate or laurylstearylthiodipropionate or mixtures thereof. 2. The polymer mixture is formed by emulsion polymerization and bulk formation by dissolving a conjugated diolefin-vinyl aromatic hydrocarbon block copolymer and polystyrene or a conjugated diolefin polymer or a copolymer of conjugated diolefin and styrene in a styrene monomer. The odorless resin composition according to claim 1, which is a blend with an impact-resistant rubber-modified styrene polymer obtained by polymerization, bulk suspension polymerization, or a mixture thereof.