JPH0995582A - Vinyl chloride resin composition excellent in resistances to impact and thermal discoloration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride resin compsn. excellent in resistances to impact and thermal discoloration by compounding a vinyl chloride resin with a graft copolymer obtd. by grafting specific monomers in three stages onto a butadiene rubber latex having a particle size increased with a specific compd. SOLUTION: A vinyl chloride resin compsn. in an amount of 100 pts.wt. is preprd. by compounding 99-70 pts.wt. vinyl chloride resin with 1-30 pts.wt. graft copolymer which is obtd. by grafting methyl methacrylate, styrene and methyl methacrylate (the sum of these monomers being 50-20 pts.wt.) successively in this order in three stages onto 50-80 pts.wt. (solid basis) butadiene rubber polymer latex which is obtd. by the emulsion polymn. of 100 pts.wt. butadiene monomer in an aq. medium in the presence of 0.5-3.0 pts.wt. sodium carbonate and has a solid content of 35wt.% or higher and an average particle size of 0.06-12μm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin composition excellent in impact resistance and heat resistant coloration.

[0002]

2. Description of the Related Art Vinyl chloride resins are widely used in various fields because of their excellent mechanical and chemical properties, but they have the drawback of low impact resistance. have. To remedy this drawback,
ABS resin, MBS resin and AAS resin in which a hard resin is reinforced with an elastic body (copolymer in which monomers such as methyl methacrylate, styrene and acrylonitrile are graft-polymerized to a polyacrylic acid alkyl ester rubber polymer)
A method has been proposed in which an impact-resistant modified resin such as the above is added to a vinyl chloride-based resin to impart impact resistance (JP-A-57-102940, JP-A-58-152039, and JP-A-58-152039).
JP-A-60-235854). However, when these impact modifiers are blended, there is a drawback that thermal coloring occurs during molding. For this reason, many studies have been conducted to improve this drawback, for example, a method of blending a stabilizer with the above resin has been conducted (Abe Yoshinaga: Plastic stabilizer for PVC, Nikkan Kogyo). (Newspaper Company), this method has a problem that the blending step is added and the amount of the additive is increased, so that it cannot be said that the performance imparting effect is sufficient.

[0003]

[Means for Solving the Problems] In view of the above situation, the present inventors have made earnest studies for the purpose of providing a vinyl chloride resin composition excellent in impact resistance and heat resistant coloration. As a result, the above object was achieved by blending a vinyl chloride resin with a graft copolymer obtained by graft-polymerizing a specific monomer in three stages on a butadiene-based rubber enlarged with a specific compound. The inventors have found what is possible and have completed the present invention.

That is, the present invention relates to butadiene (a-
1) 50 to 100% by weight and 50 to 0% by weight of at least one other vinyl-based monomer (a-2) copolymerizable therewith
When the emulsion polymerization of the monomer or monomer mixture comprising and / or after the emulsion polymerization is performed, sodium carbonate is added in an amount of 0.5 to 100 parts by weight of the monomer or monomer mixture. 50 to 80 parts by weight of a butadiene-based rubber polymer latex (A) having a solid content of 35% by weight or more and an average particle size of 0.06 to 0.12 μm (by adding 3.0 to 3.0 parts by weight). In the presence of (as solid content) methyl methacrylate or a monomer mixture (b-1) containing methyl methacrylate as a main component, styrene (b-2) and methyl methacrylate or a main component containing methyl methacrylate. The monomer mixture (b-3) is sequentially and in three stages, the total amount of those monomers (b-1 to b-3).
The total amount of (B) is 50 to 20 parts by weight, and the average particle size obtained by graft polymerization is 0.15 to 0.3 μm.
And 1 to 30 parts by weight of the graft copolymer (I) containing less than 10% by weight of unenlarged particles and 99 to 70 parts by weight of vinyl chloride resin (II) (total amount of 100 parts by weight). A vinyl chloride resin composition having excellent impact resistance and heat resistant coloration.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION First, a butadiene rubber polymer latex (A) used for constituting a graft copolymer (I) of the present invention is a butadiene (such as 1,3 butadiene, 1,4 butadiene). a-1) 50 to 100% by weight and another vinyl-based monomer (a-2) 50 copolymerizable therewith
It is a latex of a butadiene-based rubber polymer obtained by emulsion-polymerizing a monomer or a mixture of monomers of 0 to 0% by weight.

Examples of other copolymerizable vinyl monomers (a-2) used for obtaining the butadiene rubbery polymer latex (A) include aromatic compounds such as styrene and α-methylstyrene. Vinyl; 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 chloride;
Vinyl halides such as vinyl bromide; vinylidene halides such as vinylidene chloride and vinylidene bromide; glycidyl group-containing vinyl monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, ethylene glycol glycidyl ether; polyfunctional vinyl Examples thereof include monomers.

The polyfunctional vinyl-based monomer is one that is copolymerizable with the above-mentioned monomers, such as divinylbenzene,
Aromatic polyfunctional vinyl compounds such as divinyltoluene; polyhydric alcohol dimethacrylates such as ethylene glycol dimethacrylate and 1,3 butanediol diacrylate; poly (meth) acrylic acid esters such as trimethacrylate and triacrylate; Carboxylic acid allyl esters such as allyl acrylate and allyl methacrylate; diallyl phthalates; di and triallyl compounds such as diallyl sebacate and triallyl triazine.

These vinyl-based monomers and polyfunctional vinyl-based monomers may be used either individually or in combination of two or more. The composition ratio of the constituent components of the butadiene rubber polymer is within the above range, and if it deviates from these ranges, the object of the present invention cannot be sufficiently achieved, which is not preferable. Further, a chain transfer agent such as t-dodecyl mercaptan can be used, if necessary, when forming the butadiene rubber polymer latex.

Next, the graft copolymer (I) of the present invention
Can be obtained by graft-polymerizing a monomer in the presence of the above-mentioned butadiene-based rubber polymer latex (A). It is important to enlarge the diameter in the range of 0.15 to 0.3 μm. Enlargement of the butadiene rubber polymer latex with this sodium carbonate is carried out to improve impact resistance, but in order to improve thermal stability and further enlargement and polymerization stability during graft polymerization. It is something to do.

Examples of the sodium carbonate salt used for this enlargement include sodium hydrogencarbonate and sodium carbonate, and the amount thereof used is butadiene (a-1) and another monomer (a) copolymerizable therewith. It is in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the total of -2). If the amount is less than 0.5 parts by weight, the increase in size is insufficient, resulting in poor impact resistance, while if it exceeds 3.0 parts by weight, the polymerization stability becomes poor.

The sodium carbonate salt is added during and / or after emulsion polymerization of the butadiene or butadiene-based monomer mixture.

Further, in order to facilitate the enlargement, the solid content of the butadiene rubber polymer latex (A) used in the production of the graft copolymer must be 35% by weight or more. Is less than 35% by weight, enlargement is difficult and impact resistance is insufficiently improved.

The graft copolymer (I) of the present invention is used in the presence of 50 to 80 parts by weight (as solid content) of the butadiene rubber polymer latex (A) having the above-mentioned constitution.
Methyl methacrylate or a monomer mixture containing methyl methacrylate as a main component (b-1) (first stage), styrene (b-2) (second stage) and methyl methacrylate or methyl methacrylate as a main component Monomer mixture (b-
3) (third stage) sequentially and in three stages, the total amount of those monomers (the total amount of the above monomers (b-1) to (b-3))
(B) Obtained by graft-polymerizing 20 to 50 parts by weight. When the amount (as solid content) of the butadiene rubber polymer latex (A) in the graft polymerization is less than 50 parts by weight, the effect of improving the impact resistance of the vinyl chloride resin is small, and when it exceeds 80 parts by weight, the moldability is improved. Will be reduced.

Methyl methacrylate used in the first stage of the graft polymerization or a monomer mixture (b-1) containing methyl methacrylate as a main component (hereinafter referred to as a methyl methacrylate monomer (b-1)). .) Is used to improve the impact resistance and compatibility with the vinyl chloride resin. For this reason, methyl methacrylate is used as the main component amount, but other copolymerizable monomers may be used in combination if necessary.

Examples of other copolymerizable monomers that can be used in combination include, for example, methacrylic acid alkyl esters such as ethyl methacrylate and propyl methacrylate; acrylic acid such as methyl acrylate, ethyl acrylate and butyl acrylate. Alkyl ester; aromatic vinyl such as α-methylstyrene and various halogen-substituted or alkyl-substituted styrene; unsaturated nitrile such as acrylonitrile and methacrylonitrile; Body; polyfunctional vinyl monomers and the like can be mentioned.

The polyfunctional vinyl-based monomer is one that is copolymerizable with the above-mentioned monomers, and is, for example, an aromatic polyfunctional vinyl compound such as divinylbenzene or divinyltoluene;
Dimethacrylates of polyhydric alcohols such as ethylene glycol dimethacrylate and 1,3 butanediol diacrylate; poly (meth) acrylic acid esters such as trimethacrylic acid ester and triacrylic acid ester; carvone such as allyl acrylate and allyl methacrylate. Examples thereof include di- and triallyl compounds such as acid allyl ester, diallyl phthalate, diallyl sebacate, and triallyl triazine. These monomers may be used either individually or in combination of two or more.

The amount of the methyl methacrylate monomer (b-1) used in the first stage of the graft polymerization is in the range of 30 to 60% by weight based on the total amount (B) of the monomers used in the graft polymerization. Is preferred. If it is less than 30% by weight, impact resistance of the obtained vinyl chloride resin composition is not sufficient, while if it exceeds 60% by weight, the surface appearance tends to be deteriorated.

The styrene used in the second stage of the graft polymerization is used to improve the fluidity of the graft copolymer. The amount used is preferably in the range of 30 to 60% by weight based on the total amount (B) of the monomers used for graft polymerization. If it is less than 30% by weight, the fluidity of the graft copolymer will be deteriorated and fish eyes will appear, and if it exceeds 60% by weight, the impact resistance of the vinyl chloride resin composition obtained will be poor.

Further, methyl methacrylate used in the third stage of the graft polymerization or a monomer mixture (b-3) containing methyl methacrylate as a main component (hereinafter referred to as a methyl methacrylate-based monomer (b-3 )) Is used for increasing the luster of the surface of a molded product obtained from the vinyl chloride resin composition. Methyl methacrylate is used as the main component, but other copolymerizable monomers may be used in combination if necessary. As other copolymerizable monomers that can be used in combination,
Although not particularly limited, the methyl methacrylate-based monomer (b-1) described in the first stage of the above graft polymerization is preferably used.

The amount of the methyl methacrylate monomer (b-3) used in the third stage of the graft polymerization is 5 to 30% by weight based on the total amount (B) of the monomers used in the graft polymerization.
If it is less than 5% by weight, the gloss of the surface of the molded article is not sufficient, and if it exceeds 30% by weight, the fluidity of the graft copolymer is deteriorated and fish eyes are produced.

The total amount (B) of the first to third stage monomers used in the graft polymerization is 50 to 80 parts by weight (as a solid content) of 50 to 80 parts by weight of the butadiene rubber weight latex (A). The range is 20 parts by weight (total 100 parts by weight). If the total amount (B) of the monomers used for the graft polymerization is less than 20 parts by weight, the moldability will decrease, while if it exceeds 50 parts by weight, the impact resistance of the vinyl chloride resin composition will decrease.

The graft copolymer (I) of the present invention is produced by emulsion polymerization for both butadiene polymerization and graft polymerization. Examples of the polymerization initiator used during emulsion polymerization include potassium persulfate and ammonium persulfate. , Persulfates such as sodium persulfate; t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide,
Examples thereof include organic peroxides such as diisopropylbenzene hydroperoxide; azo compounds such as azobisisobutyronitrile and azobisisovaleronitrile. Further, the above compound may be combined with a sulfite, a hydrogen sulfite, a thiosulfate, a first metal salt, sodium formaldehyde sulfoxylate, dextrose or the like to be used as a redox initiator.

The emulsifier used when the diene rubber is polymerized and the graft polymerization is carried out by the emulsion polymerization to obtain the graft copolymer (I) of the present invention is not particularly limited, but for the purpose of improving the heat-resistant coloring property. Is preferably a sodium salt rather than a potassium salt, and a carboxylate is more preferable than a sulfate or a phosphate. Commercially available sodium carboxylates can be used, but sodium beef tallow and sodium oleate are preferred.

The emulsion polymerization is preferably carried out in the range of about 40 to 80 ° C., though it depends on the kind of the polymerization initiator.

Next, the graft polymer latex obtained by emulsion polymerization is added with or without suitable antioxidants, additives, etc., acids such as sulfuric acid, hydrochloric acid, phosphoric acid, calcium chloride, A coagulant such as a salt such as sodium chloride is appropriately used for coagulation, heat treatment for solidification, dehydration, washing and drying to obtain a powdery graft copolymer.

It is important that the graft copolymer (I) obtained as described above has an average particle size of 0.15 to 0.3 μm and an unexpanded small particle number of less than 10 weight. is there. This is because when the average particle size is out of the above range and the number of unenlarged small particles is 10% by weight or more, the impact resistance of the obtained graft copolymer is deteriorated.

The vinyl chloride resin (II) used in the present invention is a chlorine group-containing resin such as polyvinyl chloride or chlorinated vinyl chloride, or 70% by weight or more of vinyl chloride and another monomer copolymerizable therewith. A copolymer with 30% by weight or less of a monomer can be used. Other copolymerizable monomers include vinyl bromide, vinylidene chloride, vinyl acetate, acrylic acid, methacrylic acid, ethylene and the like.

The blending ratio of the graft copolymer (I) and the vinyl chloride resin (II) is 1 to 1 of the graft copolymer (I).
Vinyl chloride resin (II) 99-7 for 30 parts by weight
It is 0 part by weight (total amount 100 parts by weight). When the amount of the graft copolymer (I) is less than 1 part by weight, the effect of addition is small, and when it exceeds 30 parts by weight, other excellent properties of the vinyl chloride resin tend to be lost.

The vinyl chloride resin composition of the present invention is prepared by mixing the above graft copolymer (I) and the vinyl chloride resin (II) in powder form with a ribbon blender, a Henschel mixer, etc. , An extruder or the like.
A method of mixing the vinyl chloride resin and the graft copolymer latex and pulverizing the mixture through steps such as coagulation, solidification, washing and drying may be used. Upon mixing by these various methods, known stabilizers, plasticizers, solvents, processing aids, colorants and the like can be added as necessary.

[0030]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. "Parts" in the examples and comparative examples represent "parts by weight". In addition, various physical properties in Examples and Comparative Examples were measured by the following methods.

(1) Particle size and particle size distribution The resin composition was kneaded using a 6-inch roll at 185 ° C., pressed at 185 ° C. and a pressure of 50 Kg / cm ² , and molded, and then TEM (permeation). Image analysis was performed using an electron microscope) to measure the particle size and particle size distribution. In addition,
The particle size distribution was expressed as a weight percentage of unenlarged small particles.

(2) Scale The amount of scale (lumps) after polymerization was evaluated according to the following criteria. ○… None △… Slightly generated ×… Large amount generated

(3) Izod impact strength The resin composition was kneaded using a 6-inch roll at 185 ° C., press-molded at 185 ° C. and a pressure of 50 Kg / cm ² , and then measured according to ASTM D-256. I went.

(4) Heat-resistant coloring resistance Using a 6-inch roll, 100 g of the resin composition was kneaded at a kneading temperature of 185 ° C., a rotation speed of the front roll of 14 rpm, and a rotation speed of the rear roll of 16 rpm. After kneading for a minute, the color resistance was visually evaluated. ◎… Very good ○… Good ×… Poor

(5) Fisheye The resin composition was passed through a 30 mmφ uniaxial extruder (temperature 1
(90 ° C.) A film having a thickness of 0.1 mm was formed and visually evaluated. ○… None △… Slightly generated ×… Large amount generated

(6) Gloss The resin composition was passed through a 30 mmφ uniaxial extruder (temperature 1
(90 ° C.) A film having a thickness of 0.1 mm was formed and visually evaluated. ○: Good △: Cloudy ×: No luster

Examples 1 to 19 and Comparative Examples 1 to 18 (1) Production of butadiene rubber polymer latex Polymer materials having the following composition were charged in a pressure-resistant autoclave and reacted at 50 ° C. for 15 hours while stirring. Then, a butadiene rubber polymer latex (A-1 to A-9) was produced.

Polymerization raw material: 1,3 butadiene (Bd) (amount shown in Table 1 below) styrene (St) (amount shown in Table 1 below) divinylbenzene (DVB) (amount shown in Table 1 below) t-dodecyl mercaptan (T-DM) (Amount shown in Table 1 below) Diisopropylbenzene hydroperoxide 0.4 part Sodium pyrophosphate 1.5 parts Ferrous sulfate 0.02 part Dextrose 1 part Emulsifier (compound shown in Table 1 below) 3 Part Deionized water (amount shown in Table 1 below) NaHCO ₃ (amount shown in Table 1 below)

[0039]

[Table 1]

(2) Production of Graft Copolymer The butadiene rubber polymer latexes (A-1 to A-9) produced in the above (1) are used, and they are shown in Table 2 and Table 3.
The amount (as solid content) described in (1) was charged into a flask, the atmosphere was replaced with nitrogen, and then the thickening agent described in Tables 2 and 3 was added as a 10% aqueous solution, and the mixture was stirred for 30 minutes to be enlarged. It was Next, the amount of the emulsifier shown in Tables 2 and 3 was added as a 7% aqueous solution for stabilization, and then 0.6 part of Rongalit was added to maintain the internal temperature at 70 ° C. As the first stage of grafting, MMA or MMA / EA mixture described in Tables 2 and 3 (where MMA is methyl methacrylate and EA is ethyl acrylate; hereinafter the same) 0.2 parts per 100 parts Part of CHP
The mixture containing (cumene hydroperoxide) was added dropwise over 1 hour and then held for 1 hour. Then, in the presence of the polymer obtained in the first stage, the amount of S described in Tables 2 and 3 as the second stage of grafting was used.
A mixture of t (styrene) and 0.2 parts of CHP was added dropwise over 1 hour, and then the mixture was held for 2 hours. Then 0.2 parts of CHP was added to the amounts of MMA listed in Tables 2 and 3 as the third graft stage in the presence of the polymers obtained in the first and second graft stages. The resulting mixture was added dropwise over 50 minutes and then held for 1 hour to terminate the polymerization.

Then, 0.5 part of BHT (antioxidant manufactured by Sumitomo Chemical Co., Ltd.) was added to the obtained graft copolymer latex, and then a 0.2 wt% aqueous sulfuric acid solution was added. It was allowed to coagulate and heat treated to solidify at 90 ° C. Thereafter, the solidified product was washed with warm water and further dried to obtain various graft copolymer (I) powders. The measurement results of the particle size and the particle size distribution are shown in Tables 2 and 3.

(3) Preparation of vinyl chloride resin composition The amount of the graft copolymer (I) obtained in the above (2) and the average polymer 70 in the amounts shown in Tables 2 and 3 are used.
0 vinyl chloride resin (II) and 3 parts of Metablen (registered trademark) P-550 (manufactured by Mitsubishi Rayon Co., Ltd., lubricant),
1 part of Metablen (registered trademark) P-710 (manufactured by Mitsubishi Rayon Co., Ltd., lubricant) and 3 parts of octyltin mercapto-based stabilizer until the temperature reaches 110 ° C. with a Henschel mixer.
The mixture was mixed for 0 minutes to obtain a vinyl chloride resin composition. Then, the vinyl chloride resin composition was used to measure Izod impact strength, heat resistant coloration, fish eye, and luster. The results obtained are shown in Tables 2 and 3.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

The vinyl chloride resin composition of the present invention is obtained by enlarging a butadiene rubber polymer latex with sodium carbonate and adding a methyl methacrylate monomer, styrene and a methyl methacrylate monomer thereto. A graft copolymer obtained by three-step graft polymerization is blended with a vinyl chloride resin, so that it is remarkably excellent in impact resistance, heat resistant coloration and surface appearance as compared with conventional vinyl chloride resin compositions. Is.

Claims (5)

[Claims] 1. A monomer comprising 50 to 100% by weight of butadiene (a-1) and 50 to 0% by weight of at least one other vinyl monomer (a-2) copolymerizable therewith, or When emulsion-polymerizing a monomer mixture in an aqueous medium and /
Or, after emulsion polymerization, sodium carbonate is added in an amount of 0.5 to 100 parts by weight with respect to 100 parts by weight of the above-mentioned monomer or monomer mixture.
The solid content obtained by adding 3.0 parts by weight is 35
% Or more and an average particle size of 0.06 to 0.12μ
m butadiene rubber polymer latex (A) 50
To 80 parts by weight (as solid content), methyl methacrylate or a monomer mixture (b-1) containing methyl methacrylate as a main component, styrene (b-2) and methyl methacrylate or methyl methacrylate. Of the monomer mixture (b-3) containing as a main component in a sequential manner and in three stages, the total amount of these monomers (the total amount of b-1 to b-3) (B) is 50.
Graft copolymers (I) 1 to 30 having an average particle size of 0.15 to 0.3 μm obtained by graft polymerization in an amount of ˜20 parts by weight and less than 10% by weight of unexpanded particles.
A vinyl chloride resin composition having excellent impact resistance and heat-resistant colorability, which comprises 100 parts by weight of vinyl chloride resin (II) and 99 to 70 parts by weight (total amount 100 parts). 2. The vinyl chloride resin composition excellent in impact resistance and heat resistant coloration according to claim 1, wherein the sodium carbonate salt is sodium hydrogen carbonate. 3. The vinyl chloride resin composition excellent in impact resistance and heat discoloration resistance according to claim 1, wherein the sodium carbonate salt is sodium carbonate. 4. The vinyl chloride-based resin excellent in impact resistance and heat-resistant coloration according to claim 1, wherein the emulsifier used in the polymerization and graft polymerization of butadiene rubber is sodium carboxylate. Resin composition. 5. The vinyl chloride resin composition excellent in impact resistance and heat discoloration resistance according to claim 4, wherein the sodium carboxylate is sodium oleate.