JPH0291143A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To improve heat resistance, weatherability, impact resistance, processing (molding) stability and mechanical strengths by compounding a mixture of a chlorinated polymer and an alpha-methylstyrene-acrylonitrile copolymer with a specified polymer mixture. CONSTITUTION:A mixture (A) is obtd. by mixing 80-40 pts.wt. (hereinbelow merely pts.) chlorinated polymer which is a mixture of a vinyl chloride polymer and, if necessary, a chlorinated vinyl chloride polymer with 20-60 pts. alpha- methylstyrene-acrylonitrile copolymer. Another mixture (B) is obtd. by mixing 80-20wt.% (hereinbelow merely %) graft polymer obtd. by grafting vinyl chloride and, if necessary, a mixture of another monomer therewith onto 30-80% ethylene-vinyl acetate copolymer consisting of 80-20% ethylene and 20-80% vinyl acetate with 20-80% impact resistance-reinforcing agent obtd. by emulsion polymn. (e.g., a modified methyl methacrylate-butadiene-styrene resin contg. an acrylate component and an acrylonitrile component). 100 pts. component A is compounded with 8-20 pts. component B.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a thermoplastic resin composition that has good heat resistance, weather resistance, and impact resistance, as well as good processing stability, processing molding stability, and mechanical strength. relating to things.

<Prior Art> Chlorine-containing resin products have excellent properties such as flame retardancy, chemical resistance, mechanical strength, and weather resistance, and are therefore used in large quantities in a wide variety of applications such as pipes and building materials.

However, chlorine-containing resin products have relatively low heat resistance (and impact resistance is not always sufficient), so despite having excellent flame retardancy, chemical resistance, mechanical strength, and weather resistance, Application fields that require such heat resistance and impact resistance include pipes and building materials that are used under relatively harsh conditions. Examples include underground pipes.

Until now, many methods have been proposed for imparting heat resistance and impact resistance to chlorine-containing resin products, but none of these methods have been able to sufficiently improve the heat resistance or impact resistance, or the weather resistance Each of these has some drawbacks, such as poor fluidity in the die, uneven thickness of the molded product, poor dynamic thermal stability, and poor processability, and it is not always possible to adjust them. do not have.

For example, JP-A-57-14687 discloses a graft copolymer obtained by reacting a vinyl chloride polymer, a copolymer of α-methylstyrene and acrylonitrile, and a butadiene rubber with a monovinyl aromatic compound and a vinyl cyanide compound or methacrylate. Blends have been shown to improve heat and impact resistance. However, conventional graft copolymers made by reacting butadiene rubber with monovinyl aromatic compounds and vinyl cyanide compounds or methacrylates used as impact modifiers have poor weather resistance, and resin compositions containing these copolymers are molded. Processed hard vinyl chloride resin products are undesirable because their impact strength decreases significantly when used outdoors for long periods of time.

Also, JP-A-56-117519 and JP-A-58
Publication No. 88918 discloses heat resistance, impact resistance, and weather resistance using a resin composition made of a vinyl chloride resin, a chlorinated vinyl chloride resin, and a hardening agent whose main component is acrylic rubber. A cable protection tube for underground cables is shown. However, the resin composition 1) in which acrylic rubber is used alone as an impact reinforcement agent has poor fluidity in the die, uneven thickness, and insufficient moldability, which is not preferable.

<Problems to be Solved by the Invention> The present invention provides a thermoplastic resin composition that does not impair the characteristics of chlorine-containing resins, has high heat resistance and impact resistance, and has excellent mechanical strength. There is a particular thing.

Means for Solving the Problems> As a result of extensive research, the present inventors mixed α-methylstyrene-acrimitrile copolymer fe in order to impart heat resistance to the chlorine-containing polymer, and also added impact resistance to the chlorine-containing polymer. A graft polymer obtained by graft polymerizing vinyl chloride or a monomer mixture mainly composed of vinyl chloride in the presence of an ethylene-vinyl acetate copolymer and a polymer produced by emulsion polymerization to impart properties. By mixing an impact strengthener to create a resin composition and molding it, it maintains the properties of chlorine-containing resin, such as flame retardancy, chemical resistance, rigidity, and weather resistance, while maintaining heat resistance and impact resistance. The inventors of the present invention have found that the molded product has excellent dynamic thermal stability and excellent moldability without causing uneven thickness.

That is, in the present invention, 80 to 40 parts by weight of the chlorine-containing polymer and α
-Methylstyrene-acrylonitrile copolymer 20-6
0 parts by weight of a polymer mixture consisting of 100 parts by weight,
Ethylene 8cr-20% by weight and vinyl acetate 20-80%
In the presence of Ti amount% of ethylene-vinyl acetate copolymer,
A graft polymer obtained by graft polymerizing vinyl chloride or a monomer mixture mainly composed of vinyl chloride so that the copolymer has a Ti content of 80 to 80% by weight, and an impact-resistant material manufactured by an emulsion polymerization method. 8 to 20 polymer mixtures with reinforcing agents
An object of the present invention is to provide a thermoplastic resin composition in which parts by weight are arranged in parts.

The thermoplastic resin composition of the present invention is characterized by a chlorine-containing polymer which is a vinyl chloride polymer or a mixture of a vinyl chloride polymer and a chlorinated vinyl chloride polymer.
For a mixture of acrylonitrile copolymers in a specific proportion,
A graft polymer of vinyl chloride or a monomer mixture mainly composed of vinyl chloride to a specified member ethylene-vinyl acetate copolymer, or a polyfunctional monomer and a monomer mainly composed of vinyl chloride or vinyl chloride The purpose of the present invention is to incorporate a specific ratio mixture of impact strength enhancers produced by emulsion polymerization, which are mixed diene-styrene resins or acrylic multicomponent resins.

When a vinyl chloride polymer is used alone as a chlorine-containing polymer, it has good dynamic thermal stability and is advantageous in terms of processing stability.When a mixture of a vinyl chloride polymer and a chlorinated vinyl chloride polymer is used, it has good heat resistance. Improves sexual performance. Furthermore, the advantage of using a graft polymer is that the range of processing conditions under which impact resistance can be developed is wider.

By blending Sara 1 with an impact-strengthening agent produced by an emulsion polymerization method and a methyl methacrylate-butadiene-styrene resin that has been modified to improve its weather resistance, the fluidity in the die during molding is good, and the processability is improved. However, the tensile strength of the molded product is improved, and when an acrylic multi-component resin is added, the weather resistance is further improved.

The vinyl chloride polymer used in the present invention is a vinyl chloride homopolymer or a vinyl chloride monomer of 90 it' For example, it is a copolymer with vinyl acetate, vinylidene chloride, etc., and can be produced by methods such as suspension polymerization, bulk polymerization, and emulsion polymerization.

The chlorinated vinyl chloride polymer to be used can be produced by a known method, for example, by suspending the vinyl chloride polymer alone or with a chlorinated hydrocarbon solvent in water and adding chlorine. It is preferable to mix 5% to 50% by weight of the chlorine-containing polymer.If it is less than 6% by weight, the heat resistance will not be improved sufficiently, and if it is more than 50% by weight, the processing stability will be insufficient. Become.

The α-methylstyrene-acrylonitrile copolymer used in the present invention is a copolymer consisting of 90 to 60% by weight of α-methylstyrene and 10 to 40% by weight of acrylonitrile.

The mixing ratio of the chlorine-containing polymer and the α-methylstyrene-acrylonitrile copolymer used in the present invention is 80 to 40 parts by weight of the chlorine-containing polymer and 20 to 60 parts by weight of the α-methylstyrene-acrylonitrile copolymer. There is a need.

α-methylstyrene-acrylonitrile copolymer is 20
If it is less than 60 parts by weight, the improvement in heat resistance will be insufficient, and if it is more than 60 parts by weight, the improvement in impact resistance will be insufficient, which is not preferable.

The content of vinyl acetate in the ethylene-vinyl acetate copolymer used in the graft polymer of the present invention is 2OTx amount%.
It is necessary that the content is 80% by weight or less.

The content of vinyl acetate in the copolymer is 20fffffi%
Below, the compatibility with the chlorine-containing polymer is poor, resulting in a decrease in mechanical strength and impact resistance. On the contrary, the content of vinyl acetate in the copolymer is 807! If te is 1% or more, the impact resistance will be insufficient.

Ethylene-vinyl acetate copolymer has 8
It is added in an amount of 0% by weight or more and 80% by weight or less. If it is less than 80% by weight, the impact resistance will be insufficient, and if it exceeds 80% by weight, the heat resistance and mechanical strength will decrease, which is not preferable. Furthermore, the ethylene-vinyl acetate copolymer of the present invention has a melt index (ASTMD-1283).
) is preferably in the range of 0.5 to 200F/10 minutes.

Furthermore, in the composition of the present invention, an ethylene-methacrylic acid ester copolymer is used in combination with an ethylene-vinyl acetate copolymer in an amount not exceeding the amount of the ethylene-vinyl acetate copolymer in the graft polymer. It is also possible to use

In addition to vinyl chloride, the vinyl chloride-based monomer used in the graft polymer of the present invention includes fatty acid vinyl ester, vinylidene halide, acrylic acid alkyl ester, methacrylic acid alkyl ester, acryloni! - Examples include lyl, alkyl vinyl ether, ethylene and its derivatives, propylene, etc., but the amount added must be kept at 80% or less of the monomer content combined with vinyl chloride.

Further, as the polyfunctional compound used in the cross-linked graft polymer of the present invention, diallyl esters of phthalic acid such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl maleate, diallyl fumarate, diallyl itaconate, etc. diallyl esters of ethylenically unsaturated dibasic acids, diallyl esters of saturated dibasic acids such as diallyl adipate, diallyl acetate, diallyl sebacate, diallyl ether, triallyl cyanurate, triallyl isocyanurate, triallyl trimery tate and divinyl ethers such as ethylene glycol divinyl ether, n-butanediol divinyl ether, and octadecane divinyl ether; polyhydric alcohols such as ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dimethylene glycol diacrylate, and triethylene glycol diacrylate. dimethacrylic esters or diacrylic esters, trimethacrylic esters or diacrylic esters of polyhydric alcohols such as trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolethane trimethacrylate, trimethylolethane triacrylate, and titramethylolmethane triacrylate. Examples include acrylic esters, bismethacryloyloxyethylene phthalate, 1,8.5-triacryloylhexahydrotriazine, etc., and one or more of the above polyfunctional compounds may be used in combination.

Further, the amount of the polyfunctional compound added is not particularly limited, but it is preferably 0.01% by weight or more and 10% by weight or less based on vinyl chloride or a monomer mixture mainly composed of vinyl chloride.

As the polymerization method for the graft polymer or crosslinked graft polymer of the present invention, all methods applicable to the production of vinyl chloride-based graft polymers can be used, but suspension polymerization, bulk polymerization, or emulsion polymerization are preferably used. Legal is appropriate.

Catalysts used in suspension polymerization and bulk polymerization are not particularly limited, and include catalysts commonly used in suspension polymerization of vinyl chloride, such as lauroyl peroxide, 8,
5.5-trimethylhexanoyl peroxide, t-
Organic peroxides such as butyl peroxypivalate, diisopropyl peroxydicarbonate, acetyl cyclohexyl sulfenyl peroxide and α, α′-
Azobisisobutyronitrile, α.

-n! of azo compounds such as α′-azobis2,4-dimethylvaleronitrile! or a mixture of two or more dishes.

Suspension polymerization (The suspending agent used here is not particularly limited, and gelatin, polyvinyl alcohol, water-soluble cellulose ether, etc. that are commonly used in suspension polymerization of vinyl chloride can be used.

Emulsion polymerization - The catalyst used here is not particularly limited, and catalysts normally used for emulsion polymerization of vinyl chloride, such as potassium persulfate, ammonium persulfate, redox water-soluble catalysts, etc. are used.

The emulsifier used in emulsion polymerization is not particularly limited, but emulsifiers commonly used in emulsion polymerization of vinyl chloride, such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate, are used.

The crosslinked graft polymer of the present invention needs to have a crosslinked structure in the molecule, and more specifically, the gel content insoluble in tetrahydrofuran is 1% by weight or more, preferably 5% by weight.
It is necessary that it is above. Here, the gel content insoluble in tetrahydrofuran means 85% of the crosslinked graft polymer.
It refers to the extraction residue obtained by extracting with hot tetrahydrofuran for 22 hours using a Soxhlet extractor using a 0-mesh wire mesh as a filter.

The impact strength enhancer used in the present invention 1ζ is emulsion polymerized 1
One type of resin produced from ζ is a modified methacrylate-butadiene-styrene resin containing an acrylic acid ester component and an acrylonitrile component, and is a resin with improved weather resistance of conventional so-called MBS resin. Specifically, for example, it is a copolymer of butadiene-styrene-methyl methacrylate-acrylonitrile-acrylic acid ester. Komude acrylic acid ester is 2
-ethylhexyl acrylate, butyl acrylate,
Propyl acrylate, ethyl acrylate, etc. can be used as appropriate.

Another type of acrylic multicomponent resin used is a graft compound with improved weather resistance made by reacting a copolymer rubber mainly composed of acrylic acid ester with monomers such as methacrylate, styrene, and acrylonitrile. It is a polymer.

Both are impact-strengthening agents produced by emulsion polymerization, and are of the type that maintain and disperse particulate forms regardless of the amount of kneading energy used in processing machines.

The mixing ratio of the graft polymer or crosslinked graft polymer of the present invention and the impact strength enhancer produced by the emulsion polymerization method must be 20 to 80% by weight of the former and 80 to 20% by weight of the latter. If the former is less than 20% by weight, the fluidity within the gun will be poor and the weather resistance will be insufficient; on the contrary, 801!
If it exceeds ffi%, the impact resistance and mechanical strength will be insufficient, which is not preferable.

The mixture of the graft polymer or the crosslinked graft polymer of the present invention and the impact-strengthening agent produced by the emulsion polymerization method is a polymer mixture consisting of a chlorine-containing polymer and an α-methylstyrene-acrylonitrile copolymer. On the other hand, it is used in a range of 8 parts by weight or more and 20 parts by weight or less.

If it is less than 8 parts by weight, the improvement in impact resistance is insufficient;
If the amount is more than 20 parts by weight, heat resistance and rigidity will decrease, which is not preferable.

In molding the composition of the present invention, known stabilizers and lubricants commonly used in processing vinyl chloride resins,
Ultraviolet absorbers, antioxidants, pigments, etc. can be added as appropriate, and fillers can also be used if necessary.

The composition of the present invention is mixed using a known mixing device such as a roll main, a ribbon blender, a Henschel mixer, or a Banbury mixer. It can be used to form a desired molded product.

However, since the composition has good dynamic thermal stability, a wide range of molding conditions is possible. In addition, the obtained molded product has high mechanical strength and also exhibits excellent heat resistance, impact resistance, and weather resistance, so it is useful as general hard products such as pipes and building materials.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Note that the physical property values in the examples were measured by the following method. All parts and percentages in the examples are expressed on a weight basis.

Heat resistance evaluation: 5Krf according to JIS K7206
The Vicat softening temperature was measured and evaluated under a load of .

Evaluation of impact resistance: Charpy impact strength was measured and evaluated in accordance with JIS K7111s.

Evaluation of weather resistance: Using a Sunshine Weather-O-meter type accelerated exposure test device specified in JIS A1415, after being exposed for 100 hours under the conditions of a black panel temperature of 68°C and spraying for 18 minutes and 7120 minutes, Charpy impact testing was performed according to JIS K7111. The strength was measured and evaluated.

Mechanical strength evaluation: 20 according to JIS K7118
The tensile strength was evaluated in an atmosphere at ℃.

(The tensile speed is 10 fins/m1n) Evaluation of thickness distribution: The thickness of a formed pipe with a diameter of 180M is
Evaluation of dynamic thermal stability measured by the side spacing and evaluated using the following formula: The resin composition was filled into the main mixer head of a roller mixer W5QH type for Brabender's Plasticcorder PLV1151W, and the resin composition was heated at 200°C. The evaluation was made based on the time until it started to decompose when kneaded at 50 rpm.

<Example and Comparison 1 example> (1) Production of graft polymer In a stainless steel autoclave, 100 parts of deionized water, ethylene-vinyl acetate copolymer (Evatate R5011 manufactured by Sumitomo Chemical Co., Ltd., containing 141Nff 1% of vinyl acetate, Melt index 60F/10 minutes) 50 parts, Hydroxylepropyl methyl cellulose CMM, manufactured by Kagaku ■, Metrose ■ 65SH-50) 0.2 parts, α,α'-azobisisobutyronitrile 0.08 parts, and autoclaved. After degassing the interior to 80 wHf, remove vinyl chloride monomer to 50 wHf.
The temperature was raised to 60° C. under stirring conditions to start polymerization.

After 6 hours, polymerization was stopped, unreacted vinyl chloride monomer was purged, contents were taken out, and then dehydrated and dried to obtain graft polymer A.

The content of ethylene-vinyl acetate copolymer in this product is 5
7%, and the gel content insoluble in tetrahydrofuran is 0.9%.
It was 6.

(2) Production of graft polymer B In a stainless steel autoclave, add 100 parts of deionized water and ethylene-vinyl acetate copolymer (Sumitomo Chemical Evatate R).
5011) 50 parts, hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical, Metrose 65SH-50) 0.
2 parts, α, α′-azobisisobutyronitrile 0.08
After charging the autoclave with 0.5 parts of diallylphthalate and degassing the inside of the autoclave to 80 mHf, 50 parts of vinyl chloride monomer was charged, and the temperature was raised to 60°C under stirring conditions to start polymerization.

After 6 hours, copolymerization was stopped, unreacted vinyl chloride monomer was purged, and the contents were taken out and dehydrated and dried to obtain graft polymer B. The content of ethylene-vinyl acetate copolymer in this product was 5896, and the gel content insoluble in tetrahydrofuran was 41%.

(3) Production of graft copolymer C All processes were carried out in the same manner as in the production of graft copolymer A, except that an ethylene-vinyl acetate copolymer with a vinyl acetate content of 10% and a melt index of 70P/10 minutes was used. A graft polymer C was obtained.The content of the ethylene-vinyl acetate copolymer was 57%, and the gel content insoluble in tetrahydrofuran was 0%.

(4) Production of graft polymer In a stainless steel autoclave, add 100 parts of deionized water and ethylene-vinyl acetate polymer (Evatate manufactured by Sumitomo Chemical).
R5011) 20 parts, hydroxypropyl methylcellulose (Shin-Etsu Chemical Metrose O658H-50'') 0.
After charging 8 parts and 0.1 part of α,α'-azobisisobutyronitrile and degassing the inside of the autoclave to 3Qsu+H1, 80 parts of vinyl chloride monomer was charged, and under stirring conditions Q
The temperature was raised to 60°C to start polymerization.

After 6 hours, polymerization was stopped, unreacted vinyl chloride monomer was purged, and the contents were taken out and dehydrated and dried to obtain a graft polymer. The content of ethylene-vinyl acetate copolymer in this product was 28%, and the gel content insoluble in tetrahydrofuran was 0%.

(5) Production of graft polymer E In a stainless steel autoclave, add 100 parts of deionized water and ethylene-vinyl acetate copolymer (Sumitomo Chemical Evatate [
F] R5011) 80 parts, hydroxypropyl methylcellulose (Shin-Etsu Chemical Metrose l3165SH-50
) 0.2 parts, α,α'-azobisisobutyronitrile 0.105 parts and the inside of the autoclave was degassed to 80mH9, then 20 parts of vinyl chloride monomer was charged and the temperature was heated to 6oC under stirring conditions. The temperature was raised to start polymerization.

After 8 hours, polymerization was stopped, unreacted vinyl chloride monomer was purged, the contents were taken out, and then dehydrated and dried to obtain graft polymer E. The content of ethylene-vinyl acetate copolymer in this product was 8996, and the gel content insoluble in tetrahydrofuran was 0%.

Example 1 From 55 parts by weight of polyvinyl chloride with an average degree of polymerization of 1100 (Sumilit 5x-11F manufactured by Sumitomo Chemical) and 45 parts by weight of α-methylstyrene-acrylonitrile copolymer (monomer weight ratio 70:80). 10 parts by weight of graft weight material A, 5 parts by weight of modified methyl methacrylate-butadiene-styrene resin (HIA-23 manufactured by Kureha Chemical Co., Ltd.), 8 parts by weight of lead-based stabilizer, After blending a resin composition containing 1 part by weight of a metal soap lubricant and 1.5 parts by weight of a processability improver, a Mitsubishi Krauss KMD-60 was used with a twin-screw extruder in different directions to produce 251" p.
m rotation speed, temperature conditions (cylinder 175℃, adapter:
@170℃) Dice: [Phase] 160℃, 0158℃
Tensile strength, heat resistance, weather resistance, impact resistance, and thickness distribution were measured using a formed pipe cross-extruded at 167°C and 0180°C.

Separately, the dynamic thermal stability of the resin composition was also measured according to the method described above. Also, impact resistance and fogging are 0.
Measurements were also carried out on molded pipes that were cross-extruded under conditions in which each cylinder temperature was 5° C. higher from 0 to 0. Display the results -
11.

Example 2 Sumilit ■5x-11F was changed to Sumilit ■5x-18+ with an average degree of polymerization of 1860, and the modified methyl methacrylate-butadiene-styrene resin was changed to an acrylic multi-component resin (Kanebuchi Chemical ■Kane Ace FM). Others are
It was molded and evaluated in exactly the same manner as in Example 1.

The results are shown in Table-1.

Example 8 Molding and evaluation were carried out in exactly the same manner as in Example 1, except that 15 parts by weight of the 5X-11F55 weight part was replaced with chlorinated vinyl chloride (Kanebuchi Chemical Heat-resistant Kanevinyl). I did it.

The results are shown in Table 11c.

Examples 4 to 8 Sumilit ■5x-11F, α-methylstyrene-acrylonitrile copolymer, graft polymer A and the above)
(The molding and evaluation were performed in exactly the same manner as in Example 1 except that the number of copies of IA-28 was changed. The results are shown in Table 1.

All of the resin compositions of Examples 1 to 8 exhibited good dynamic thermal stability, and all of the molded products obtained from these resin compositions had a narrow I-stain distribution (uniform molding without uneven thickness). Its physical properties include high tensile strength, heat resistance, weather resistance, and impact resistance.

Comparative Examples 1 to 6 Example 1, except that the numbers of Sumiritz ■5x-11F, a-methylstyrene-acrylonitrile copolymer (monomer weight ratio 70:80), graft copolymer A and HIA-28 were changed. It was molded and evaluated in exactly the same manner as No. 1. The results are shown in Table-1.

Comparative Example 7 Molding and evaluation were carried out in exactly the same manner as in Example 1, except that the number of parts of graft copolymer A was reduced, HIA-28 was changed to Kane Ace FM, and the number of parts was increased. Table 1 shows the results.
It was shown to.

Comparative Example 8 A molded product was molded and evaluated in exactly the same manner as in Example 1, except that 40 parts by weight of the 55 parts by weight of Sumilit ■5x-11F5 was changed to chlorinated vinyl chloride. The results are shown in Table-1.

Comparative Example 1 has a low Vicat proofing temperature and insufficient heat resistance, and Comparative Examples 2 and 8 have low Charpy impact strength and insufficient impact resistance. Comparative Example 4 has insufficient rigidity and heat resistance, Comparative Example 6 has insufficient weather resistance, and Comparative Example 6 has insufficient impact resistance. In Comparative Example 7, the molded product had uneven thickness,
Comparative Example 8 has insufficient processability and poor dynamic thermal stability, which is not preferable due to insufficient processability.

Example 9 Molding and evaluation were performed in exactly the same manner as in Example 1, except that graft polymer A was changed to graft polymer B. The results are shown in Table-2. The resin composition of Example 9 showed good dynamic thermal stability, and the molded product obtained from this resin composition had a narrow thickness distribution (uniform molded product with no uneven thickness, and its physical properties were high tensile strength, Excellent heat resistance, weather resistance, and impact resistance.

In addition, even if the lubricant is reduced and kneaded excessively, there is little decrease in the impact strength of the steel ruby, the impact resistance is high, and its dependence on processing is small, which is an extremely excellent practical advantage.

Comparative Examples 9 to 11 Molding and evaluation were performed in exactly the same manner as in Example 1, except that the graft polymers shown in Table 2 were used instead of graft polymer A.

The results are shown in Table-2.

Comparative Example 9 has a lower tensile strength and impact resistance, Comparative Example 10 has a lower WJ impact resistance, and Comparative Example 11 has a lower tensile strength and heat resistance, which are preferable.

<Effects of the Invention> The thermoplastic resin composition of the present invention has excellent processing stability and processability, and the molded products obtained from it have excellent mechanical strength represented by tensile strength, weather resistance, flame retardance, and chemical resistance. It has excellent properties, as well as improved heat resistance and impact resistance.

Taking advantage of these excellent properties, it can be used in pipes and building materials that are used under harsh conditions. More specific applications include underground pipes for electric wires, etc.

Claims (6)

[Claims] (1) For 100 parts by weight of a polymer mixture consisting of 80 to 40 parts by weight of a chlorine-containing polymer and 20 to 60 parts by weight of α-methylstyrene-acrylonitrile copolymer, 8 parts by weight of ethylene
In the presence of an ethylene-vinyl acetate copolymer containing 0 to 20% by weight and 20 to 80% by weight of vinyl acetate, vinyl chloride or chloride is added so that the content of the ethylene-vinyl acetate copolymer is 30 to 80% by weight. Graft polymer 80 obtained by graft polymerizing a monomer mixture containing vinyl as a main component
20% by weight and 8 to 20 parts by weight of a polymer mixture of 20 to 80% by weight of an impact strength enhancer produced by an emulsion polymerization method. (2) the graft polymer mainly contains vinyl chloride;
2. The thermoplastic resin composition according to claim 1, which is obtained by graft polymerizing a monomer mixture containing a polyfunctional compound onto an ethylene-vinyl acetate copolymer. (3) The thermoplastic resin composition according to claim 1, wherein the chlorine-containing polymer is a vinyl chloride polymer. (4) The thermoplastic resin composition according to claim 1, wherein the chlorine-containing polymer is a polymer mixture of 5 to 50% by weight of a chlorinated vinyl chloride polymer and 95 to 50% by weight of a vinyl chloride polymer. . (5) The thermoplastic resin composition according to claim 1, wherein the impact strength enhancer produced by the emulsion polymerization method is a modified methyl methacrylate-butadiene-styrene resin containing an acrylic ester component and an acrylonitrile component. (6) The thermoplastic resin composition according to claim 1, wherein the impact strength enhancer produced by the emulsion polymerization method is an acrylic multicomponent resin.