JPH10120740A - Method for producing rubber-modified thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a polymerization conversion rate and a graft rate at the time of graft polymerization, to reduce a coagulum generated at the time of polymerization, and to obtain a rubber-modified thermoplastic resin by using another thermoplastic resin. The thermoplastic resin composition molded product obtained by blending in water has impact resistance, elongation and surface appearance (color tone, fish eye)
To obtain a rubber-modified ABS resin-based rubber-modified thermoplastic resin excellent in quality. SOLUTION: In the presence of 30 to 80% by weight of a rubbery polymer (a), a monomer comprising 6 to 63% by weight of an aromatic vinyl compound (b) and 2 to 49% by weight of a vinyl cyanide compound (c) The body component is polymerized using a mercaptopropionic acid alkyl ester having 6 to 14 carbon atoms in the alkyl group as a molecular weight regulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing a rubber-rich rubber-modified thermoplastic resin.
By using the above-mentioned alkyl mercaptopropionate as a molecular weight regulator, by polymerizing a monomer component in the presence of a rubber-like polymer, the polymerization conversion rate and the graft rate are improved, and the coagulum generated during the polymerization is improved. The present invention relates to a method for producing a rubber-modified thermoplastic resin having a reduced amount. By compounding the obtained rubber-modified thermoplastic resin with other thermoplastic resins,
A thermoplastic resin molded article excellent in impact resistance, elongation and surface appearance (color tone, fish eye) can be obtained.

[0002]

2. Description of the Related Art ABS resins and AES resins are widely known as rubber-modified thermoplastic resins, and are used in large quantities industrially. As a method for producing an ABS resin, the following two methods are generally known. A method obtained by copolymerizing 75 to 95% by weight of a monomer composed of styrene and acrylonitrile in the presence of 5 to 25% by weight of a rubbery polymer. An ABS resin having a high rubber content (hereinafter referred to as "rubber-rich ABS resin") obtained by copolymerizing 55 to 60% by weight of a monomer composed of styrene and acrylonitrile in the presence of 40 to 45% by weight of a rubbery polymer. Styrene-acrylonitrile copolymer obtained separately by polymerization (AS resin)
And the content of the rubbery polymer in the composition is 5 to 25.
A method of obtaining an ABS resin by adjusting the weight to% (the ABS resin obtained by this method is hereinafter referred to as “blend type AB”).
S resin)). The above method uses a rubber-rich AB
By appropriately selecting the amount of the S resin and the type of the AS resin, various types of A having different qualities can be obtained.
BS resin can be manufactured with high productivity.

However, in the ABS resin industry, further cost reduction and quality improvement are required. As a measure to reduce costs and improve quality, the rubber content of the rubber-rich ABS resin is further increased, and the blending amount of low-cost AS resin with excellent productivity is increased. And quality, especially color tones. However, when the rubber content of the rubber-rich ABS resin is increased as compared with the conventional product, the polymerization conversion and the graft ratio of the monomer component become low, and the impact resistance and elongation of the final product decrease, and There are problems such as deterioration of the molded appearance due to the occurrence.

[0004] In order to solve these problems, various studies have been made to change the type and amount of a polymerization initiator and a molecular weight regulator for the purpose of improving the graft ratio. In particular, it is well known that various approaches have been taken since a molecular weight modifier has a large effect on the graft ratio.
-Mercaptan-based molecular weight regulators such as dodecyl mercaptan and n-octyl mercaptan hardly increase the graft ratio and cause a unique mercaptan odor during handling. On the other hand, molecular weight regulators such as monoterpenoids such as α-methylstyrene and terpinolene have the disadvantage that the polymerization conversion of the final polymer is reduced.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of a rubber-rich ABS resin having an increased rubber content, improves the polymerization conversion rate and the graft rate during graft polymerization, and improves the polymerization efficiency. Reduce the coagulum generated at the time, further molded article of thermoplastic resin composition obtained by blending the obtained rubber-modified thermoplastic resin with other thermoplastic resin,
An object of the present invention is to provide a method for producing a rubber-modified ABS-based rubber-modified thermoplastic resin having excellent impact resistance, elongation, and surface appearance (color tone, fish eye).

[0006]

According to the present invention, there is provided a rubbery polymer (a) in the presence of 30 to 80% by weight of an aromatic vinyl compound (b) 6 to 63% by weight and a vinyl cyanide compound (c). 2 to 49% by weight [(a) + (b) +
(C) = 100% by weight], using a mercaptopropionic acid alkyl ester represented by the following general formula as a molecular weight regulator, to produce a rubber-modified thermoplastic resin: Is provided. (In the formula, R represents an alkyl group having 6 to 14 carbon atoms.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the rubbery polymer (a) serving as a base rubber of the rubber-modified thermoplastic resin of the present invention, for example, polybutadiene, polyisoprene, styrene-butadiene copolymer (styrene content 5 to 60% by weight) Is preferred), styrene-isoprene copolymer, acrylonitrile-butadiene copolymer, ethylene-α-olefin-based copolymer, ethylene-α-olefin-polyene copolymer, acrylic rubber, butadiene- (meth) acrylate Copolymers, polyisoprenes, styrene-butadiene block copolymers, styrene-isoprene block copolymers, hydrogenated styrene-butadiene block copolymers, hydrogenated butadiene-based polymers, ethylene ionomers and the like can be mentioned. In addition, the styrene-butadiene block copolymer and the styrene-isoprene block copolymer include those having an AB type, ABA type, a taper type, a radial teleblock type, and the like. further,
The hydrogenated butadiene-based polymer is, in addition to the hydride of the block copolymer, a styrene block and a styrene-butadiene random copolymer block, and a 1,2-vinyl bond content in polybutadiene of 20% by weight. % Or less, and a hydride of a polymer comprising a polybutadiene block having a 1,2-vinyl bond content of more than 20% by weight. These rubbery polymers (a) have the following properties:
Used alone or in combination of two or more.

The aromatic vinyl compound (b) used for the rubber-modified thermoplastic resin includes, for example, styrene,
t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N, N-diethyl-p-aminoethylstyrene,
N, N-diethyl-p-aminomethylstyrene, vinylpyridine, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, fluorostyrene, ethylstyrene, vinylnaphthalene and the like are preferred, and styrene and α-methylstyrene are particularly preferred. . These aromatic vinyl compounds may be used alone or in combination of two or more. Examples of the vinyl cyanide compound (c) include acrylonitrile and methacrylonitrile.

For the purpose of the present invention, the above (b) to (b)
In addition to the component (c), other vinyl monomers can be used as long as they do not cause any trouble. As other vinyl monomers, for example, methyl acrylate, ethyl acrylate,
Acrylates such as propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, benzyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate;
Butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate, methacrylic acid esters such as benzyl methacrylate; maleic anhydride, itaconic anhydride, citraconic anhydride and the like Unsaturated acid anhydrides; unsaturated acids such as acrylic acid and methacrylic acid; maleimide, N-methylmaleimide, N-butylmaleimide;
Α- such as N- (p-methylphenyl) maleimide, N-phenylmaleimide and N-cyclohexylmaleimide
Or an imide compound of β-unsaturated dicarboxylic acid (also referred to as a maleimide monomer); glycidyl methacrylate;
Epoxy compounds such as allyl glycidyl ether; unsaturated carboxylic amides such as acrylamide and methacrylamide; acrylamine, aminomethyl methacrylate,
Amino group-containing unsaturated compounds such as aminoethyl methacrylate, aminopropyl methacrylate and aminostyrene;
3-hydroxy-1-propene, 4-hydroxy-1-
Butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-
Examples include a hydroxyl group-containing unsaturated compound such as methyl-1-propene, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate; and an oxazoline group-containing unsaturated compound such as vinyl oxazoline. These other vinyl monomers are used alone or in combination of two or more. The content of the other vinyl monomer is preferably 20% by weight or less, more preferably 10% by weight or less in the components excluding the component (a).

The amount of the rubbery polymer (a) used in the production of the rubber-modified thermoplastic resin is 30 to 80% by weight, preferably 35 to 75% by weight, more preferably 40 to 7% by weight.
4% by weight. If the amount of the component (a) is less than 30% by weight, the effect of improving the productivity and the color tone is not sufficient.
If the amount is more than 10% by weight, the graft ratio is reduced, and the generation of fish eyes is increased in the final product containing another thermoplastic resin, and the appearance, elongation and impact resistance are significantly reduced. The amount of the aromatic vinyl compound (b) used in the production of the rubber-modified thermoplastic resin is 6 to 63% by weight,
Preferably it is 8 to 54% by weight, more preferably 13 to 54% by weight.
48% by weight. Further, a vinyl cyanide compound (c)
Is used in an amount of 2 to 49% by weight, preferably 3 to 42% by weight, and more preferably 5 to 30% by weight. Either the component (b) is less than 6% by weight, the component (b) exceeds 63% by weight, the component (c) is less than 2% by weight, or the component (c) exceeds 49% by weight. In this case, too, the effect of improving fisheye, the effect of improving color tone, the effect of improving elongation, and the effect of improving impact resistance are not sufficient, and all of them cannot be maintained at desired levels.

The graft ratio of the rubber-modified thermoplastic resin is 5% by weight or more, preferably 10% by weight or more.
When the graft ratio is less than 5% by weight, fish eyes are often generated, and the appearance and impact resistance are poor. The graft ratio is measured by the following method. Here, the graft ratio refers to the ratio of the copolymer component directly graft-bonded to the rubber-like polymer with respect to the amount of rubber in the rubber-modified thermoplastic resin. This graft ratio can be controlled by the amount of the polymerization initiator, the polymerization temperature, and the like. As a specific method of obtaining the graft ratio, first, 1 g of the rubber-modified thermoplastic resin of the present invention is charged into acetone at room temperature, stirred sufficiently, and the insoluble matter (w) is determined. On the other hand, the amount of the rubbery polymer in the insoluble matter (w) can be calculated based on the polymerization recipe. With the calculated total amount of the rubbery polymer as R, the graft ratio is determined from the following equation. Graft amount (% by weight) = [(w−R) / R] × 100

The intrinsic viscosity (methyl ethyl ketone, 30 ° C.) of the methyl ethyl ketone soluble component of the rubber-modified thermoplastic resin of the present invention is preferably 0.1 to 0.5 dl / g.
More preferably, it is 0.15 to 0.45 dl / g.
If it is less than 0.1 dl / g, the impact resistance of the obtained rubber-modified thermoplastic resin will be reduced. If it exceeds 0.5 dl / g, fish eyes will be generated more frequently and the appearance of the molded article will be poor. This intrinsic viscosity can be easily adjusted by appropriately selecting the type and amount of the molecular weight regulator and the polymerization initiator and the polymerization temperature.

The method for producing the rubber-modified thermoplastic resin of the present invention is not particularly limited, but a preferred polymerization method is an emulsion polymerization method. In the emulsion polymerization, the molecular weight regulator, emulsifier, polymerization initiator and the like of the present invention are used.

In the present invention, a mercaptopropionic acid alkyl ester having the structure shown below is used alone or in combination as a molecular weight regulator. By using this molecular weight regulator, the polymerization conversion rate and the graft rate can be improved, and the coagulum generated during the polymerization can be reduced. Also, there is an advantage that the odor at the time of handling and at the time of product recovery is significantly improved as compared with the conventional mercaptan-based molecular weight regulator.

[0015] (In the formula, R represents an alkyl group having 6 to 14 carbon atoms.) Here, the alkyl group R has 6 to 14 carbon atoms, preferably 8 to 12 carbon atoms. If the amount is outside this range, the amount of coagulum generated during polymerization increases, and the impact resistance and elongation of the final product containing another thermoplastic resin are reduced. In addition, generation of fish eyes increases, and the appearance deteriorates. Specific examples of the alkyl mercaptopropionate include dodecyl (3-mercapto) propionate, octyl (3-mercapto) propionate, and hexyl (3-mercapto) propionate.

The amount of the alkyl mercaptopropionate used is preferably 0.1 to 3 parts by weight, more preferably 0.15 to 2 parts by weight, based on 100 parts by weight of the total of the rubber component and the monomer component. is there. If the amount is less than 0.1 part by weight, fish eyes are remarkably generated in the final product, which is not preferable. On the other hand, if it exceeds 3 parts by weight,
As the polymerization conversion rate decreases, the graft rate decreases,
It is not preferable because the impact resistance of the final product deteriorates. The above-mentioned alkyl mercaptopropionate may be used in combination with another molecular weight regulator. In this case, the amount of the other molecular weight regulator used is preferably less than 50% by weight of the total amount used.

Here, other molecular weight regulators include, for example, halogenated hydrocarbons (eg, chloroform, bromoform, etc.), mercaptans (eg, n-dodecylmercaptan, t-dodecylmercaptan, n-octylmercaptan, n-octylmercaptan) -Hexadecyl mercaptan), terpenes (eg, dipentene, terpinolene, etc.), α-methylstyrene dimer, and the like.

The polymerization initiator used in the production of the rubber-modified thermoplastic resin of the present invention includes organic peroxides such as hydroperoxide, alkyl perester, percarbonate, peroxyketal, ketone peroxide, and peroxides. Potassium sulfate, azobisisobutyronitrile and the like are used alone or in combination. These polymerization initiators are also used in combination with a reducing agent such as a sugar-containing iron pyrophosphate formulation, a sulfoxylate formulation, or a mixed formulation of a sugar-containing iron pyrophosphate formulation / sulfoxylate formulation. The amount of the polymerization initiator to be used is 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the total of the rubber component and the monomer component. If the amount is less than 0.01 part by weight, the polymerization conversion rate is low and a large amount of unreacted monomer remains, which is not preferable in production. On the other hand, when the amount exceeds 5 parts by weight, the molecular weight of the grafted copolymer is remarkably reduced, and sufficient impact resistance cannot be obtained.

The emulsifier used in the emulsion polymerization includes an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant. Among them, examples of the anionic surfactant include a higher alcohol sulfate, an alkylbenzene sulfonate, a fatty acid sulfonate, and a phosphoric acid type. As the nonionic surfactant, an alkyl ester type, an alkyl ether type, an alkyl phenol type or the like of polyethylene glycol is usually used. Further, examples of the amphoteric surfactant include those having a carboxylate, a sulfate, a sulfonate, or a phosphate as an anion portion, and an amine salt, a quaternary ammonium salt, or the like as a cation portion. Specific examples of the amphoteric surfactant include:
Betaines such as lauryl betaine and stearyl betaine, and amino acid types such as lauryl-β-alanine, stearyl-β-alanine, lauryl di (aminoethyl) glycine, and octyl di (aminoethyl) glycine are used. These emulsifiers can be used alone or in combination of two or more. The amount of the emulsifier used is usually about 0 to 3 parts by weight based on 100 parts by weight of the total of the rubber component and the monomer component.

In the emulsion polymerization, the above-mentioned molecular weight regulator,
In addition to a polymerization initiator, an emulsifier, etc., various electrolytes, a pH adjuster, and the like may be used in combination, if necessary, to prepare a rubber component (in terms of solid content) and a total of 100 parts by weight of a monomer component. Is generally used at a polymerization temperature of 5 to 110 ° C. for a polymerization time of 0.5 to 24 hours.

The rubber-modified thermoplastic resin of the present invention usually comprises
It is manufactured by adding an antioxidant to the latex obtained by the above emulsion polymerization, coagulating it by a usual method, washing the obtained powder with water, and drying it.
The obtained rubber-modified thermoplastic resin can be pelletized by a kneading machine such as an extruder.

The powder of the rubber-modified thermoplastic resin of the present invention before pelletization may be blended with a silicone oil or a lubricant in order to improve the powder properties. This silicone oil can prevent blocking of the rubber-rich rubber-modified thermoplastic resin powder and improve the impact resistance of the resin. Examples of the silicone oil include organopolysiloxanes represented by polydimethylsiloxane, polydiethylsiloxane, polymethylphenylsiloxane, or modified products thereof. Silicone oil has a molecular weight of preferably 2,300 to 6 from the viewpoint of dispersibility and handling.
000, kinematic viscosity is preferably 30 to 10,000c
s (25 ° C.).

The silicone oil can be added to any of the latex system after polymerization of the rubber-modified thermoplastic resin, the finishing step in the coagulation / drying step, and the powder. The addition amount of the silicone oil is 0.01 to 6 parts by weight, preferably 0.02 to 5 parts by weight, based on 100 parts by weight of the rubber-modified thermoplastic resin of the present invention. If the amount is less than 0.01 part by weight, the effect of preventing blocking is poor, and the impact resistance is not improved. On the other hand, when the amount exceeds 6 parts by weight, poor discharge in an extruder and an increase in fish eyes in a final product are caused.

By using a lubricant together with silicone oil, the impact resistance of the rubber-modified thermoplastic resin can be further improved, and the rubber-rich rubber-modified thermoplastic resin powder can be stored for a long period of time. . Examples of the lubricant include fatty acids such as stearic acid and behenic acid; fatty acid metal salts such as zinc stearate, magnesium stearate, aluminum stearate, calcium stearate, barium laurate, and cadmium myristate;
Fatty acid amides such as oleic acid amide, erucic acid amide, ethylenebisstearylamide, ethylenebispalmitic acid amide, ethylenebisoleic acid amide, sorbitan stearic acid esters such as butyl stearate, stearyl stearate, sorbitan monostearate, and pentaerythritol Pentaerythritol stearic acid esters such as tetrastearate, glycerin fatty acid esters such as oleic acid monoglyceride, fatty acid esters such as hydrogenated castor oil, higher alcohols such as stearyl alcohol, and the like, preferably in combination with fatty acid metal salts and fatty acid amides is there.

The amount of the lubricant to be added depends on the amount of the rubber-modified thermoplastic resin 1
The amount is 0.1 to 20 parts by weight, preferably 0.2 to 15 parts by weight based on 00 parts by weight. If the amount is less than 0.1 part by weight, the effect of further improving the impact resistance of the rubber-modified thermoplastic resin and the long-term storage of the resin powder is poor. It causes poor appearance of molded products such as fogging and burns. A lubricant can also be added to any of the latex system after polymerization of the rubber-modified thermoplastic resin, the finishing step in the coagulation / drying step, and the powder.

Further, the rubber-modified thermoplastic resin of the present invention comprises:
By blending another thermoplastic resin, a thermoplastic resin composition excellent in impact resistance, elongation and surface appearance (color tone, fish eye) can be obtained. Here, as other thermoplastic resins, for example, styrene-based resins such as ABS resin, AES resin, AAS resin, AS resin, HIPS and PS having a rubber-like polymer content of less than 50% by weight; polyethylene, polypropylene, etc. Olefin resin; PA6,
Polyamide resins such as PA66, PA46 and PA12; polyester resins such as polybutylene terephthalate, polyethylene terephthalate and polyarylate; polycarbonate resins, polyphenylene ether resins such as polyphenylene ether or polyphenylene ether / styrene resins; polyacetals, vinyl chloride resins;
There are polysulfone, PPS, polyethersulfone, ethylene-vinyl acetate copolymer, EVOH and the like, and these can be used alone or in combination of two or more.

Preferred other thermoplastic resins include the following, each alone or in combination. In the presence of a rubber-like polymer, a monomer comprising at least two groups selected from the group consisting of an aromatic compound, a vinyl cyanide compound, a (meth) acrylate ester, and a maleimide monomer is polymerized. And a rubbery polymer content of 5
Other rubber modified thermoplastics less than 0% by weight. Here, the rubbery polymer and monomer here include those described above. The intrinsic viscosity (in methyl ethyl ketone, at 30 ° C.) of a soluble portion of methyl ethyl ketone of the other rubber-modified thermoplastic resin is preferably 0.1 to 1 dl / g, more preferably 0.2 to 0.6 dl / g. g. An aromatic vinyl compound, a vinyl cyanide compound, a (meth) acrylic acid ester, a monomer obtained by polymerizing at least two kinds of monomers selected from the group of maleimide monomers, and having an intrinsic viscosity (methyl ethyl ketone In a solvent at 30 ° C.) is preferably 0.2 to 1.3 dl /
g, more preferably 0.3 to 1 dl / g, particularly preferably 0.35 to 0.8 dl / g.

As the above, for example, ABS resin, A
Examples thereof include an ES resin, an AAS resin, and an MBS resin. Among them, an ABS resin and an AES resin are preferable. Examples of the above include the following copolymers (a) to (c). (A) A copolymer of an aromatic vinyl compound and a vinyl cyanide compound. The preferred composition ratio is such that the former monomer is 50 to 9
9 polymerization%, the latter being 50-1% by weight. (B) A copolymer of an aromatic vinyl compound and a (meth) acrylate. (C) A copolymer comprising an aromatic vinyl compound, a maleimide-based monomer and, if necessary, a vinyl cyanide compound and / or a (meth) acrylate. In addition, an unsaturated acid anhydride monomer is used in place of the maleimide-based monomer, and the obtained copolymer is imidized, and the obtained post-imide type copolymer is also included herein. The aromatic vinyl compound, vinyl cyanide compound, (meth) acrylic acid ester, and maleimide-based monomer here are the same as those described above.

The composition ratio of each component in the above-mentioned thermoplastic resin composition containing a rubber-modified thermoplastic resin and another thermoplastic resin is such that the rubber-like polymer (a) in the rubber-modified thermoplastic resin is in the composition. Each component is appropriately blended so as to be preferably contained in an amount of 3 to 35% by weight. The more preferable content of the component (a) is 5 to 30% by weight.
If the content of the component (a) is less than 3% by weight, sufficient impact resistance cannot be obtained. On the other hand, if it exceeds 35% by weight, the molded article becomes soft, which is not preferable. On the other hand, when another rubber-modified thermoplastic resin other than the rubber-modified thermoplastic resin of the present invention is used as the other thermoplastic resin, the rubber-like polymer contained in the other rubber-modified thermoplastic resin (hereinafter referred to as “the thermoplastic resin”) is used. (Referred to as "(a ') component") is as follows. The component (a ') is also regarded as the component (a) and satisfies the following conditions. [(A) + (a ')] content of 3
To 35% by weight, and the content of (a) is 3 to 35% by weight. Preferably, the content of [(a) + (a ')] is 5 to 5.
30% by weight, and the content of (a) is 5 to 30% by weight.

The thermoplastic resin composition is produced by kneading the rubber-modified thermoplastic resin of the present invention, other thermoplastic resins, and, if necessary, various additives. As a kneading method, there is a method using an extruder, a roll, a Banbury mixer, a kneader, or the like. A preferable method is a method using an extruder, and examples of the extruder include a single screw extruder and a twin screw extruder. When kneading various components using the above-described kneading method, all components may be kneaded at once, some components may be kneaded first, and the remaining components may be added at once or divided. It may be kneaded. Various additives can be added to the rubber-modified thermoplastic resin as needed. When kneading is required, kneading can be performed by the method described above. As various additives, known colorants, pigments, weathering agents, antistatic agents,
Examples include antioxidants, flame retardants, thermal aging inhibitors, plasticizers, antibacterial and antifungal agents. The rubber-modified thermoplastic resin of the present invention is usually blended with the other thermoplastic resin to form a thermoplastic resin composition, which is subjected to injection molding, sheet extrusion,
Various molded products can be molded by vacuum molding, profile extrusion, injection press, foam molding, blow molding, hollow molding and the like.

[0031]

The present invention will now be described more specifically with reference to examples. In the examples, parts and% are based on weight unless otherwise specified.

Example 1 A polybutadiene rubber latex (60 parts in solid content) and a styrene-butadiene rubber latex (10 parts in solid content) were added to a flask, and 150 parts of ion-exchanged water, 5.4 parts of styrene and acrylonitrile were added. 1 part, 0.175 part of n-dodecylmercaptopropionate was further added, and after the temperature in the flask was raised to 60 ° C., 0.2 part of sodium pyrophosphate and 0.01 part of ferrous sulfate hydrate were added. ,
A solution prepared by dissolving 0.4 part of glucose in 20 parts of ion-exchanged water was added, and 0.1 part of t-butylperoxyisopropyl carbonate was further added to initiate polymerization.
It was kept at 0 ° C. After polymerization for 1 hour, styrene 16.
2 parts, acrylonitrile 6.3 parts, n-dodecylmercaptopropionate 0.525 parts, t-butyl peroxyisopropyl carbonate 0.2 parts were continuously added over 2 hours, and the polymerization was further performed for 1 hour to carry out a reaction. Was completed.

Thereafter, octadecyl 3 (3 ', 5-di-t-butylhydroxyphenyl) propionate and 2,2'-methylene-bis (4-ethyl-6-t-butylphenol) were added as anti-aging agents. Thus, a copolymer latex was obtained. The polymerization conversion of the obtained copolymer latex was 99%, and the generated coagulum was 0.2%. This copolymer latex is coagulated using sulfuric acid,
Washed and dried. The graft ratio of the obtained rubber-modified thermoplastic resin was 28%. The method of evaluating the polymerization conversion rate and the coagulum is shown below.

Polymerization conversion rate The residual unreacted monomer amount in the final polymer was calculated by FID gas chromatography, and the total polymerization charge amount (the amount obtained by subtracting the residual unreacted monomer amount from the total polymerization charge amount (base rubber + monomer)) was calculated. The ratio to (base rubber + monomer) was defined as the polymerization conversion. Quantitative determination of polymerized coagulum The coagulum adhering to the polymerization feed and the latex after polymerization were filtered through a 200 mesh wire net, and the residue was recovered, washed with water, dehydrated, dried at a constant temperature (40 ° C), and dried. The agglomerate was quantified and expressed as a percentage of the actual charged weight of the polymer. Agglomerate (%) = (Agglomerate / actual weight of polymer) ×
100

Next, a copolymer of 21.2 parts of a rubber-modified thermoplastic resin and styrene and acrylonitrile (composition ratio: styrene 75%, acrylonitrile 25%, intrinsic viscosity of methyl ethyl ketone soluble matter = 0.6 dl / g) 7
8.8 parts, and 1.0 part of ethylenebisstearylamide, 0.3 part of magnesium stearate, silicone oil (dimethylpolysiloxane; kinematic viscosity = 100)
(cs, molecular weight = about 6,000), and then stirred and mixed using a Henschel mixer. This mixture is subjected to a cylinder setting temperature of 200 ° C. and a diameter of 40 mmφ.
It was pelletized by an extruder. After producing test pieces from the pellets by the molding method described below, various characteristic values were measured by the following methods. Table 1 shows the results.

Test Piece Molding Method Using the pellets obtained by the above method as a molding material, test pieces for measurement were prepared under the following molding conditions, and the Izod impact strength, high-speed falling weight impact strength, and elongation were measured. Molding machine; 5 oz. In-line screw type molding machine Mold temperature; 50 ° C. ± 5 ° C. Molding machine setting conditions; Cylinder set temperature: 200 ° C. Injection pressure: Primary pressure 75 to 95 kg / cm ² G, secondary pressure 5
0 kg / cm ² G Back pressure: 5 kg / cm ² G Molding sile: Injection 15 seconds, loading 1
0 seconds, curing 40 seconds, cycle start 2 seconds

Measurement of Izod impact strength ASTM D256 (1/4 ", notched, unit = kg
f · cm / cm). Measurement of High-speed Drop Weight Impact A test piece was prepared using a mold having a film gate having a thickness of 2.4 mm, a width of 55 mm, and a length of 80 mm, and using this test piece, a high-speed drop weight impact tester [Shimadzu ( Co., Ltd.] under the conditions of a receiving hole diameter of 30 mmφ, a hitting rod diameter of 16 mmφ, and a falling weight speed of 2.4 m / sec. Measurement of Elongation The molded test piece was measured with a universal material testing machine (Instron testing machine) in accordance with ASTM D638, and the elongation (%) was determined.

Measurement of Fish Eye A fish eye measurement sheet sample was prepared by the following method, and the fish eye was measured. A 50-ton press machine heated at 220 ° C. is prepared. The pellet obtained by the above method is sandwiched between SUS mold plates (30 cm × 30 cm × 0.5 mm) (10 to 1).
5g). It is sandwiched between presses as it is, and a pressure of 0 to 0.5 kg / cm ² is applied, and the mixture is heated for 5 minutes. The pressure is slowly applied (up to 10 kg / cm ² ), and the pellet sample (molten) that has protruded from between the mold plates is slowly pulled out. The sample is drawn out into a film, and the thickness is about 10-30.
Pull out 1 m or more with a thickness of μm. A circle (area = 10 cm ² ) having a diameter of 3.57 cm is drawn on the film sample, and the number of fish eyes in the circle is counted (the diameter is 0.2 mm or more). The above is performed at three points, the total is divided by the area, the number per 1 cm ² is obtained, and the fish eye is evaluated. The larger the number, the worse the molded appearance.

Example 2 60 parts of a polybutadiene rubber latex was added to a flask in terms of solid content, and then 150 parts of ion-exchanged water, 7.2 parts of styrene, 2.8 parts of acrylonitrile, and 0.175 of n-dodecylmercaptopropionate were added. After further increasing the temperature in the flask to 60 ° C., 0.2 part of sodium pyrophosphate, 0.01 part of ferrous sulfate hydrate,
A solution prepared by dissolving 0.4 part of glucose in 20 parts of ion-exchanged water was added, and 0.1 part of t-butylperoxyisopropyl carbonate was further added to initiate polymerization.
It was kept at 0 ° C. After polymerization for 1 hour, styrene 21.
6 parts, acrylonitrile 8.4 parts, n-dodecylmercaptopropionate 0.525 parts, t-butylperoxyisopropyl carbonate 0.2 parts are continuously added over 2 hours, and the polymerization is further performed for 1 hour to effect a reaction. Was completed.

After completion of the reaction, the copolymer latex was treated in the same manner as in Example 1, and then 24.7 parts of the obtained rubber-modified thermoplastic resin was mixed with a copolymer of styrene and acrylonitrile (composition ratio). An intrinsic viscosity of 75% styrene, 25% acrylonitrile, and methyl ethyl ketone soluble content =
(0.6 dl / g) 75.3 parts were added and then Example 1
A molded article was prepared in the same manner as in Example 1 and evaluated. Table 1 shows the results.

Example 3 A polybutadiene rubber latex (50 parts in solid content) was added to a flask, and then 150 parts of ion-exchanged water, 9 parts of styrene, 3.5 parts of acrylonitrile, and 0.175 part of n-dodecylmercaptopropionate were added. In addition, after the temperature in the flask was raised to 60 ° C., 0.2 part of sodium pyrophosphate, 0.01 part of ferrous sulfate hydrate, and 0.4 part of glucose were dissolved in 20 parts of ion-exchanged water. The solution was added, and 0.1 part of t-butyl peroxyisopropyl carbonate was further added to start polymerization, and the temperature of the hot bath was reduced to 70 ° C.
Kept. After polymerization for 1 hour, 27 parts of styrene, 10.5 parts of acrylonitrile, 0.525 part of n-dodecylmercaptopropionate, and 0.2 part of t-butylperoxyisopropyl carbonate were continuously added over 2 hours. The polymerization was further continued for 1 hour to complete the reaction.

After the reaction was completed, the copolymer latex was treated in the same manner as in Example 1, and then 29.4 parts of the obtained rubber-modified thermoplastic resin was mixed with a copolymer of styrene and acrylonitrile (composition ratio). An intrinsic viscosity of 75% styrene, 25% acrylonitrile, and methyl ethyl ketone soluble content =
(0.6 dl / g) 70.6 parts were added and then Example 1
A molded article was prepared in the same manner as in Example 1 and evaluated. Table 1 shows the results.

Example 4 n-octylmercaptopropionate was used in place of n-dodecylmercaptopropionate as a molecular weight regulator, and cumenehydro was used in place of t-butylperoxyisopropyl carbonate as a polymerization initiator. Polymerization to evaluation were performed under the same conditions as in Example 2 except that peroxide was used. Table 1 shows the results.

Comparative Example 1 90 parts of a polybutadiene rubber latex was added to a flask in terms of solid content, and then 150 parts of ion-exchanged water, 1.8 parts of styrene, 0.7 parts of acrylonitrile, and 0.175 of n-octylmercaptopropionate were added. After further increasing the temperature in the flask to 60 ° C., 0.2 part of sodium pyrophosphate, 0.01 part of ferrous sulfate hydrate,
A solution prepared by dissolving 0.4 part of glucose in 20 parts of ion-exchanged water was added, and 0.1 part of cumene hydroperoxide was further added to initiate polymerization, and the temperature of the warm bath was maintained at 70 ° C. 1
After polymerizing for hours, 5.4 parts of styrene, 2.1 parts of acrylonitrile, 0.525 part of n-octylmercaptopropionate, and 0.2 part of cumene hydroperoxide are continuously added over 2 hours. The reaction was completed by polymerizing for 1 hour.

After completion of the reaction, the copolymer latex was treated in the same manner as in Example 1, and then 16.0 parts of the obtained rubber-modified thermoplastic resin was mixed with a copolymer of styrene and acrylonitrile (composition ratio). An intrinsic viscosity of 75% styrene, 25% acrylonitrile, and methyl ethyl ketone soluble content =
0.6 dl / g), 84.0 parts, followed by Example 1
A molded article was prepared in the same manner as in Example 1 and evaluated. Table 2 shows the results.

Comparative Examples 2-3 N-dodecyl mercaptan was used in place of n-octylmercaptopropionate, which is the molecular weight regulator of Example 3,
Example 3 except that α-methylstyrene dimer was used.
Polymerization to evaluation were performed under the same conditions as described above. Table 2 shows the results
Shown in

Comparative Example 4 Comparative Example 4 was repeated under the same conditions as in Example 3 except that n-stearylmercaptopropionate was used instead of n-octylmercaptopropionate, which is a molecular weight regulator of Example 3. Up to the example was done. Table 2 shows the results.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

According to the present invention, when a rubber-modified thermoplastic resin is obtained, a specific molecular weight regulator is used, so that the polymerization conversion and the grafting ratio are improved, and the agglomerates generated during the polymerization are reduced. And can further contribute to polymerization productivity. Since the rubber-modified thermoplastic resin obtained by the present invention has a high rubber component content, the effect of improving the impact resistance can be obtained with a small amount, so that it is easy to cope with the expandability. In addition, thermoplastic resins such as AS resins are excellent in productivity and low in cost, and therefore, by blending them, it is possible to mass-produce low-cost ABS resins with high productivity. A molded article of a thermoplastic resin composition obtained by mixing another thermoplastic resin with the obtained rubber-modified thermoplastic resin is excellent in impact resistance, elongation and surface appearance (color tone, fish eye).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08F 212: 02 220: 42) (72) Inventor Noboru Oshima 2-11-24 Tsukiji, Chuo-ku, Tokyo Nippon Gosei Rubber Co., Ltd. Inside

Claims (1)

[Claims] 1. An aromatic vinyl compound (b) 6-63% by weight and a vinyl cyanide compound (c) 2-49% by weight in the presence of 30-80% by weight of a rubbery polymer (a) (A) + (b) + (c) = 100% by weight] is polymerized using an alkyl mercaptopropionate represented by the following general formula as a molecular weight regulator. A method for producing a rubber-modified thermoplastic resin. (In the formula, R represents an alkyl group having 6 to 14 carbon atoms.)