JPH06200105A - Polyvinyl chloride-based resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyvinyl chloride-based resin composition good in impact and thermal coloring resistances. CONSTITUTION:This polyvinyl chloride-based resin is obtained by blending a graft copolymer resin prepared by adding an alkali metallic carbonate in or after the graft copolymerization which is a synthetic stage in carrying out the graft copolymerization of a vinylic monomer or a monomer mixture containing methyl methacrylate as an essential component with a butadiene- based rubber polymer latex with a polyvinyl chloride-based resin in one or multi-stage with a polyvinyl chloride-based resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl chloride resin composition having good impact resistance and heat resistant coloration.

[0002]

2. Description of the Related Art Polyvinyl chloride resins are widely used in various fields because of their excellent mechanical and chemical properties, but they have the drawback of being inferior in impact resistance. In order to overcome this drawback, ABS resin, MBS resin in which a hard resin is reinforced with an elastic body, polyacrylic acid alkyl ester rubber polymer grafted with monomers such as methyl methacrylate, styrene and acrylonitrile are used. A method has been proposed in which a resin for impact resistance modification is blended with a polyvinyl chloride resin to impart impact resistance. However, if these impact modifiers are blended, the heat-resistant coloring property at the time of molding becomes poor, which is not preferable.

Therefore, many studies have been conducted to improve this drawback, and conventionally, a method of adding a stabilizer to a polyvinyl chloride resin by blending has been carried out. However, this method has a problem in that the blending step is added and the amount of the additive is increased, so that the performance imparting effect cannot be said to be sufficient.

[0004]

The present invention has been made to solve the above drawbacks, and provides a polyvinyl chloride resin composition excellent in impact resistance and heat resistant coloration.

In view of the present situation as described above, the present inventors diligently studied a method for enhancing the impact resistance of a polyvinyl chloride resin with an impact resistance modifier, and as a result, as a result, methyl methacrylate was added to a butadiene rubber polymer latex. Vinyl-based monomer contained as an essential component or other 1 which can be copolymerized with it
Obtained by adding an alkali metal carbonate during or after the graft polymerization, which is the synthetic stage of the graft polymerization of a monomer mixture consisting of one or more vinyl monomers in one or multiple steps. It has been found that a polyvinyl chloride resin composition excellent in impact resistance and heat resistant coloration can be obtained by blending such a graft copolymer resin with a polyvinyl chloride resin, and arrived at the present invention.

[0006]

DISCLOSURE OF THE INVENTION The present invention comprises 99-70% by weight of a polyvinyl chloride resin (A), 50-100% by weight of 1,3-butadiene and one or more vinyls copolymerizable therewith. 40 to 90 parts by weight (as a solid content) of a butadiene rubber polymer (a) latex obtained by emulsion polymerization of a monomer or monomer mixture consisting of 0 to 50% by weight of a system monomer in an aqueous medium. In the presence, a monomer mixture (b) consisting of a vinyl monomer containing methyl methacrylate as an essential component or one or more other vinyl monomer copolymerizable therewith (b) 60 to 10 wt. Graft polymer resins (B) 1 to 30 obtained by graft polymerization of one part or multiple steps and obtained by adding a carbonate of an alkali metal during or after the graft polymerization, which is the synthetic step thereof. Wt% and In Ranaru polyvinyl chloride resin composition.

The present invention will be described in detail below. The polyvinyl chloride resin (A) used in the present invention is a chlorine group-containing resin such as polyvinyl chloride or chlorinated vinyl chloride, or 7
A copolymer of 0% by weight or more of vinyl chloride and 30% by weight or less of another monomer copolymerizable therewith can be used.
Other copolymerizable monomers include vinyl bromide, vinylidene chloride, vinyl acetate, acrylic acid, methacrylic acid, ethylene and the like.

Next, the graft copolymer resin (B) of the present invention
Will be described in detail. First, the rubber polymer constituting the graft copolymer resin (B) of the present invention comprises 50 to 100% by weight of 1,3-butadiene and one or more vinyl monomers 0 to 50 copolymerizable therewith. It is a butadiene-based rubber polymer (a) obtained by emulsion polymerization of a monomer or monomer mixture consisting of wt% in an aqueous medium.

Examples of vinyl monomers used for forming the rubber polymer (a) include aromatic vinyl such as styrene and α-methylstyrene, methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate,
Acrylic alkyl esters such as ethyl acrylate and n-butyl acrylate, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as methyl vinyl ether and butyl vinyl ether, vinyl halides such as vinyl chloride and vinyl bromide, vinylidene chloride and bromide. Examples thereof include vinylidene halides such as vinylidene, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, vinyl monomers having glycidyl such as ethylene glycol glycidyl ether, and the like.

Further, as the crosslinkable monomer among the vinyl monomers, those copolymerizable with them, for example, aromatic polyfunctional vinyl compounds such as divinylbenzene and divinyltoluene, ethylene glycol dimethacrylate, 1,3 Polyhydric alcohols such as butanediol diacrylate, trimethacrylic acid esters, triacrylic acid esters, allyl acrylates, allyl esters of carboxylic acids such as allyl methacrylate, diallyl phthalates, diallyl sebacates, di- and triallyl compounds such as triallyl triazines Etc.

The vinyl-based monomer and the crosslinkable monomer are 1
One kind or two or more kinds can be used. The composition ratio of the constituent components of the rubber polymer (a) is within the above range,
If it deviates from these ranges, the object of the present invention cannot be sufficiently achieved, which is not preferable. When forming the rubber polymer (a), a chain transfer agent such as t-dodecyl mercaptan can be used if necessary.

The graft copolymer resin (B) constituting the present invention comprises a monomer containing methyl methacrylate as an essential component in the presence of the latex of the butadiene rubber polymer (a) having the above-mentioned constitution. 1) a monomer mixture (b) containing at least one other vinyl-based monomer copolymerizable with
It can be obtained by graft polymerization in stages or in multiple stages.

In the present invention, methyl methacrylate can be used alone as the monomer used for the graft polymerization, but if necessary, a vinyl-based monomer copolymerizable therewith,
For example, esters of methacrylic acid such as ethyl methacrylate and propyl methacrylate, esters of acrylic acid such as methyl acrylate, ethyl acrylate and butyl acrylate, styrene such as styrene, α-methylstyrene and various halogen-substituted and alkyl-substituted styrenes. , Acrylonitrile, unsaturated nitrile such as methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, vinyl monomers having a glycidyl group such as allyl glycidyl ether and a monomer mixture with the above-mentioned crosslinkable monomer are used. be able to. These monomers may be used alone or in combination of two or more.

The amount of the monomer or monomer mixture (b) used for the graft polymerization is 1 to 40 parts by weight (as solid content) of 40 to 90 parts by weight of the butadiene rubber polymer (a) latex.
It is in the range of 0 to 60 parts by weight, and if it is less than 10 parts by weight, the moldability is inferior, and if it exceeds 60 parts by weight, the polyvinyl chloride resin composition obtained is inferior in impact resistance, which is not preferable.

The graft polymerization may be carried out by adding the monomer or the mixture of monomers (b) at once, or by adding the monomer or the mixture of monomers in two or more portions. It is also possible to carry out the graft polymerization in multiple stages. By carrying out the graft polymerization in multiple stages in this way, it is possible to make the outside of the graft copolymer resin (B) a component having good compatibility with the polyvinyl chloride resin (A) to be mixed therewith. Is.

As the synthetic method, both rubber polymerization and graft polymerization are carried out by emulsion polymerization. As a polymerization initiator for producing the graft copolymer resin (B), potassium persulfate, ammonium persulfate, sodium persulfate, etc. are used. Organic peroxides such as persulfate, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, diisopropylbenzene hydroperoxide, azobisisobutyronitrile, azobisisovaleronitrile, etc. An azo compound or the like can be used. In addition, the above compound may be combined with a sulfite, a hydrogen sulfite, a thiosulfate, a first metal salt, sodium formaldehyde sulfoxylate, dextrose and the like to be used as a redox initiator. The polymerization can be appropriately performed within the range of about 40 to 80 ° C., though it depends on the kind of the polymerization initiator. A known emulsifier can be appropriately used as the emulsifier.

The graft copolymer resin (B) thus obtained is added with or without addition of a suitable antioxidant or additive, or an acid such as sulfuric acid, hydrochloric acid or phosphoric acid, calcium chloride, sodium chloride or the like. Coagulate using a coagulant such as salt of
After heat treatment to solidify, dehydration, washing, and drying are performed to obtain a powdery graft copolymer resin (B).

In the present invention, it is essential to add an alkali metal carbonate in order to improve the heat coloring property. The timing of addition is (1) during graft polymerization, (2) after graft polymerization, and (3) after coagulation.
It is necessary to add more than once.

Generally, an alkali metal carbonate is used as a viscosity reducer at the time of rubber polymerization or added for the purpose of improving the polymerization rate. However, addition at the time of rubber polymerization is not preferable because the effect of heat coloring resistance is low. In order to bring out the effect of heat-resistant coloring, it is necessary to add them at the time of (1), (2) and (3). In addition, addition at these times has the effect of improving the thermal coloring property, and in the case of (1), it has the effect of preventing a decrease in pH during polymerization, suppressing the generation of aggregates, and further suppressing the viscosity.
In the case of (2), the mechanical stability of the latex after polymerization is excellent. However, (3) is particularly preferable as the effect of only improving the thermal coloring property.

The amount of the alkali metal carbonate added is 0.05 to 3.0 parts by weight, preferably 0.1 to 2.0 parts by weight, based on 100 parts by weight of the total of the graft copolymer resin (B). It is a department. If the addition amount is less than 0.05 parts by weight, the effect of improving the heat colorability is not obtained, which is not preferable. Further, if it exceeds 3.0 parts by weight, fish eyes are generated in the molded product, which is not preferable. Examples of the alkali metal carbonate used in the present invention include potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate and the like.

The polyvinyl chloride resin composition of the present invention comprises
The above-mentioned graft copolymer resin (B) and polyvinyl chloride resin (A) are mixed in powder form with a ribbon blender, a Henschel mixer or the like and formed by a known kneader, extruder or the like. The polyvinyl chloride resin (A) may be mixed with the graft copolymer resin (B), and the mixture may be powdered through steps such as coagulation, solidification, washing and drying.
When mixing by these various methods, known stabilizers,
A plasticizer, a processing aid, a colorant and the like can be added as required.

The polyvinyl chloride resin composition of the present invention is
The polyvinyl chloride resin (A) is 99 to 70% by weight, and the graft copolymer resin (B) is 1 to 30% by weight. Graft copolymer resin (B)
If less than 1% by weight, there is almost no effect of addition, and 3
If the amount exceeds 0% by weight, polyvinyl chloride resin (A)
It is not preferable because the other excellent properties of (3) tend to be lost.

[0023]

The present invention will be described in more detail with reference to the following examples, which are not intended to limit the present invention.
In the following Examples and Comparative Examples, "part" means "part by weight",
"%" Represents "% by weight". Various physical properties in the following Examples and Comparative Examples were measured by the following methods.

Izod impact 6 inch roll, kneading temperature 185 ° C., 50 kg /
cm ² After press molding at 185 ° C., ASTM D-2
The measurement was performed according to 56.

Heat-coloring property: Using a 6-inch roll, the kneading temperature is 185 ° C., the rotation number is 14 rpm for the front roll, 16 rpm for the rear roll, and 100 g of the material
Was kneaded, sampled every 5 minutes, and kneaded for a total of 30 minutes, and the coloring property was visually evaluated. ◎… Very good. ○: Good. ×: defective.

(Example 1) (1) Synthesis of butadiene rubber polymer (a) latex 1,3 butadiene (Bd) 75 parts styrene (St) 25 parts t-dodecyl mercaptan (t-DM) 0.5 part Diisopropylbenzene hydroperoxide 0.4 parts Sodium pyrophosphate 1.5 parts Ferrous sulfate 0.02 parts Dextrose 1 part Potassium oleate 2 parts Deionized water 100 parts Charge components of the above composition were charged into a pressure autoclave, The mixture was reacted for 15 hours at 50 ° C. with stirring to produce a butadiene rubber polymer (a) latex (polymerization rate 98%, average particle size 0.10 μm, glass transition temperature −28).
C).

(2) Synthesis of Graft Copolymer Resin (B) Butadiene rubber polymer (a) Latex 70 parts (solid content) Potassium oleate 1.2 parts Sodium sulfosuccinate dioctyl ester 0.03 parts After being sufficiently stabilized, 30 parts of a 0.2% hydrochloric acid aqueous solution was gradually added to cause coagulation and enlargement, and the latex pH was returned to 7.0 with an aqueous sodium hydroxide solution, Rongalit 0.6 parts sodium carbonate 1.0 part 150 parts of deionized water (as a whole) was charged into a flask purged with nitrogen, the internal temperature was kept at 70 ° C., and a mixture of 10 parts of methyl methacrylate (MMA) and 0.2 part of cumene hydroperoxide (CHP) was added for 1 hour. After dropping, it was held for 1 hour.
Then, in the presence of the obtained polymer, as a second step, a mixture of St 10 parts CHP 0.2 part was added dropwise over 1 hour, and then the mixture was maintained for 2 hours.
Then, in the presence of the polymer obtained in the first and second steps, as a third step, a mixture of 10 parts of MMA and 0.2 parts of CHP was added dropwise over 50 minutes, and then the mixture was kept for 1 hour. The polymerization was terminated (average particle size 0.35 μm).

After adding 0.5 parts of butylated hydroxytoluene (BHT) to the obtained graft copolymer latex, 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation, and 9
It was heat-treated and solidified at 0 ° C. After that, wash the coagulum with warm water,
Further, it was dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of Polyvinyl Chloride Resin Composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, Metabrene ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
1 part of Metablen ^R- P-710 (manufactured by Mitsubishi Rayon Co., Ltd.) and 15 parts of the powder of the graft copolymer resin (B) obtained in (2) above were heated to 110 ° C. for 10 minutes with a Henschel mixer. A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. The results of these evaluations are shown in Table 1.

(Examples 2 to 5) Except that the addition timing and amount of sodium carbonate are as shown in Table 1,
A polyvinyl chloride resin composition was obtained in the same manner as in Example 1. The results of these evaluations are shown in Table 1.

(Example 6) (1) Synthesis of butadiene rubber polymer latex (a) Bd 100 parts t-DM 0.6 part Diisopropylbenzene hydroperoxide 0.4 part Sodium pyrophosphate 1.5 parts Sulfuric acid first Iron 0.005 part Dextrose 1 part Glauber's salt 1 part Potassium oleate 0.8 part Deionized water 100 parts Charge components of the above composition were charged into a pressure autoclave and reacted at 50 ° C. for 72 hours with stirring, then 3 parts of potassium oleate and 10 parts of deionized water were added to produce a butadiene rubber polymer (a) latex (polymerization rate 98%, average particle size 0.46 μm, glass transition temperature −55 ° C.).

(2) Synthesis of graft copolymer resin (B) Butadiene rubber polymer (a) Latex 80 parts (solid content) Potassium oleate 1.2 parts Rongalit 0.4 parts Deionized water (as a whole) 150 parts of the mixture was charged into a flask in which the atmosphere was replaced with nitrogen, the internal temperature was kept at 70 ° C., a mixture of 10 parts of St and 0.2 part of CHP was added dropwise over 1 hour, and then the mixture was kept for 1 hour.
Then, in the presence of the obtained polymer, as a second stage, a mixture of MMA 10 parts CHP 0.2 parts was continuously added dropwise over 1 hour, and then maintained for 2 hours to terminate the polymerization (average particle size). 0.50 μm).

B was added to the obtained graft copolymer latex.
After 0.5 part of HT was added, a 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation, and 1.5 parts of sodium carbonate was added, followed by heat treatment and solidification at 90 ° C. After that, the coagulated product was washed with warm water and further dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of polyvinyl chloride resin composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, and Metablen ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
1 part of METABLEN ^R P-710 (manufactured by Mitsubishi Rayon Co., Ltd.) and 7 parts of the powder of the graft copolymer resin (B) obtained in (2) above were heated to 110 ° C. for 10 minutes with a Henschel mixer. A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. The results are shown in Table 1.

Example 7 (1) Synthesis of butadiene rubber polymer latex (a) Bd 55 parts St 40 parts Divinylbenzene 5 parts Diisopropylbenzene hydroperoxide 0.4 parts Sodium pyrophosphate 1.5 parts Sulfuric acid first Iron 0.02 part Dextrose 1 part Potassium oleate 2 parts Deionized water 100 parts Charge components of the above composition are charged into a pressure autoclave and reacted at 50 ° C. for 15 hours while stirring to give a butadiene rubber polymer ( a) Latex was produced (polymerization rate 98%, average particle size 0.08 μm, glass transition temperature-12)
C).

(2) Synthesis of Graft Copolymer Resin (B) Butadiene rubber polymer (a) Latex 75 parts (solid content) Potassium oleate 1.2 parts Rongalit 0.5 parts Deionized water (as a whole) 150 parts of the mixture was charged into a flask in which the atmosphere was replaced with nitrogen, the internal temperature was maintained at 70 ° C., a mixture of MMA 15 parts St 10 parts CHP 0.5 part was added dropwise over 1 hour, and then the mixture was maintained for 1 hour to complete the polymerization. (Average particle diameter 0.10 μm).

B was added to the obtained graft copolymer latex.
After 0.5 part of HT was added, a 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation, and 1.5 parts of sodium carbonate was added, followed by heat treatment and solidification at 90 ° C. After that, the coagulated product was washed with warm water and further dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of polyvinyl chloride resin composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, Metabrene ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
1 part of METABLEN ^R P-710 (manufactured by Mitsubishi Rayon Co., Ltd.) and 20 parts of the powder of the graft copolymer resin (B) obtained in the above (2) were mixed with a Henschel mixer for 10 minutes. A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. These results are shown in Table 1.
Shown in.

Example 8 (1) Synthesis of butadiene rubber polymer (a) latex Bd 80 parts St 17 parts Divinylbenzene 3 parts Diisopropylbenzene hydroperoxide 0.4 parts Sodium pyrophosphate 1.5 parts Sulfuric acid first Iron 0.02 part Dextrose 1 part Potassium oleate 2 parts Deionized water 100 parts Charge components of the above composition are charged into a pressure autoclave and reacted at 50 ° C. for 15 hours while stirring to give a butadiene rubber polymer ( a) A latex was prepared (polymerization rate 98%, average particle size 0.10 μm, glass transition temperature-27).
C).

(2) Synthesis of Graft Copolymer Resin (B) Butadiene rubber polymer (a) Latex 50 parts (solid content) Potassium oleate 1.2 parts Rongalit 1.0 part Deionized water (as a whole) 150 parts of the mixture was charged into a flask purged with nitrogen, the internal temperature was maintained at 70 ° C., a mixture of 50 parts of MMA and 1.0 part of CHP was added dropwise over 1 hour, and then the mixture was maintained for 1 hour to terminate the polymerization ( Average particle diameter 0.15 μm).

B was added to the obtained graft copolymer latex.
After 0.5 part of HT was added, a 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation, and 1.5 parts of sodium carbonate was added, followed by heat treatment and solidification at 90 ° C. After that, the coagulated product was washed with warm water and further dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of Polyvinyl Chloride Resin Composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, Metabrene ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
And METABLEN ^R P over 710 (manufactured by Mitsubishi Rayon Co., Ltd.) 1 part (2) obtained in the graft copolymer resin (B) The components of 10 parts of the powder, 10 minutes until 110 ° C. in a Henschel mixer A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. These results are shown in Table 1.
Shown in.

(Comparative Examples 1 to 3) Except that the addition timing and the addition amount of sodium carbonate are as shown in Table 1,
A polyvinyl chloride resin composition was obtained in the same manner as in Example 1. The results of these evaluations are shown in Table 1.

Comparative Example 4 (1) Synthesis of butadiene rubber polymer (a) latex Bd 40 parts St 60 parts t-DM 0.2 parts diisopropylbenzene hydroperoxide 0.4 parts sodium pyrophosphate 1.5 parts Ferrous sulfate 0.01 part Dextrose 1 part Potassium oleate 1.5 parts Deionized water 100 parts Charge components of the above composition were charged into a pressure autoclave and reacted with stirring at 50 ° C. for 36 hours to obtain butadiene. A rubber-based polymer (a) latex was produced (polymerization rate: 98%, average particle size: 0.21 μm, glass transition temperature: +5).
C).

(2) Synthesis of Graft Copolymer Resin (B) Butadiene rubber polymer (a) Latex 75 parts (solid content) Potassium oleate 1.2 parts Rongalit 0.5 parts Deionized water (as a whole) 150 parts of the mixture was charged into a flask in which the atmosphere was replaced with nitrogen, the internal temperature was maintained at 70 ° C., a mixture of MMA 15 parts St 10 parts CHP 0.5 part was added dropwise over 1 hour, and then the mixture was maintained for 1 hour to complete the polymerization. (Average particle size 0.25 μm).

B was added to the obtained graft copolymer latex.
After adding 0.5 parts of HT, a 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation, and 1.0 part of sodium carbonate was added, followed by heat treatment and solidification at 90 ° C. After that, the coagulated product was washed with warm water and further dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of polyvinyl chloride resin composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, Metabrene ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
And METABLEN ^R P over 710 (manufactured by Mitsubishi Rayon Co., Ltd.) 1 part (2) obtained in the graft copolymer resin (B) The components of 10 parts of the powder, 10 minutes until 110 ° C. in a Henschel mixer A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. These results are shown in Table 1.
Shown in.

(Comparative Example 5) The monomer used in the graft polymerization was S
A polyvinyl chloride resin composition was obtained in the same manner as in Example 8 except that sodium carbonate was added as shown in Table 1 instead of t. The results of these evaluations are shown in Table 1.

Comparative Example 6 (1) Synthesis of butadiene rubber polymer latex (a) Bd 100 parts t-DM 0.6 part Diisopropylbenzene hydroperoxide 0.4 part Sodium pyrophosphate 1.5 parts Sulfuric acid first Iron 0.005 part Dextrose 1 part Glauber's salt 1 part Potassium oleate 0.8 part Deionized water 100 parts Charge components of the above composition were charged into a pressure autoclave and reacted at 50 ° C. for 72 hours with stirring, then 3 parts of potassium oleate and 10 parts of deionized water were added to produce a butadiene rubber polymer (a) latex (polymerization rate 98%, average particle size 0.46 μm, glass transition temperature −55 ° C.).

(2) Synthesis of Graft Copolymer Resin (B) Butadiene rubber polymer (a) Latex 30 parts (solid content) Potassium oleate 1.2 parts Rongalit 1.4 parts Deionized water (as a whole) 150 parts of the mixture was charged into a flask in which the atmosphere was replaced with nitrogen, the internal temperature was maintained at 70 ° C., a mixture of St 30 parts CHP 0.6 parts was added dropwise over 1 hour, and then the mixture was maintained for 1 hour.
Then, in the presence of the obtained polymer, as a second stage, a mixture of MMA 40 parts CHP 0.8 part was continuously added dropwise over 1 hour and then maintained for 2 hours to terminate the polymerization (average particle size). 0.53 μm).

To the obtained graft copolymer latex, 1.0 part of sodium carbonate and 0.5 part of BHT were added, and then a 0.2 wt% sulfuric acid aqueous solution was added to cause coagulation,
It was heat-treated and solidified at 90 ° C. After that, the coagulated product was washed with warm water and further dried to obtain a graft copolymer resin (B) powder.

(3) Preparation of Polyvinyl Chloride Resin Composition 100 parts of polyvinyl chloride resin having an average degree of polymerization of 700, 3 parts of dioctyltin mercaptide as a stabilizer and a lubricant, Metabrene ^R P-550 (Mitsubishi Rayon Co., Ltd.) 2),
And METABLEN ^R P over 710 (manufactured by Mitsubishi Rayon Co., Ltd.) 1 part (2) obtained in the graft copolymer resin (B) The components of 10 parts of the powder, 10 minutes until 110 ° C. in a Henschel mixer A polyvinyl chloride resin composition was obtained by mixing. The impact resistance and the heat colorability of a molded product molded using the obtained resin composition were measured. These results are shown in Table 1.
Shown in.

[0053]

[Table 1]

[0054]

The present invention is obtained by graft-polymerizing a vinyl-based monomer or a monomer mixture containing methyl methacrylate as an essential component onto a butadiene-based rubber polymer latex, and during the synthesis thereof, an alkali metal carbonate is used. By adding a salt, it is possible to obtain a polyvinyl chloride resin composition which is extremely excellent in impact resistance and heat discoloration resistance when the graft copolymer resin to be synthesized is mixed with the polyvinyl chloride resin.

Claims (1)

[Claims] 1. A polyvinyl chloride resin (A) 99-70.
%, 1,3-butadiene 50-100% by weight, and a monomer or monomer mixture consisting of 0-50% by weight of one or more vinyl monomers copolymerizable therewith in an aqueous medium. In the presence of 40 to 90 parts by weight (as solid content) of the latex of the butadiene rubber polymer (a) obtained by emulsion polymerization,
One stage of 60 to 10 parts by weight of a monomer mixture (b) consisting of a vinyl-based monomer containing methyl methacrylate as an essential component or one or more other vinyl-based monomers copolymerizable therewith. Alternatively, from 1 to 30% by weight of a graft copolymer resin (B) obtained by graft polymerization in multiple stages and obtained by adding an alkali metal carbonate during or after the graft polymerization, which is the synthetic step thereof. A polyvinyl chloride resin composition comprising: