JPH06107743A - Production of graft copolymer - Google Patents

Abstract

PURPOSE:To impart higher chemical resistance and gas barrier properties to ABS resin. CONSTITUTION:This production of graft copolymer comprises a step 1 of subjecting a monomer consisting essentially of an acrylate to emulsion polymerization in a conjugated diene rubber latex and a step 2 of subjecting a mixture of vinyl cyanide and an aromatic vinyl (rich in vinyl cyanide content) in a latex obtained in the step 1 to emulsion polymerization. Thereby, a graft copolymer keeping high impact resistance, excellent in chemical resistance and gas barrier properties and having god balance of physical properties is obtained.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to a method for producing a graft copolymer. More specifically, the present invention is a method in which a conjugated diene rubber produced by emulsion polymerization is graft-polymerized with an acrylic acid ester monomer mixture, and then a high proportion of vinyl cyanide monomer and a small proportion of aromatic vinyl monomer are obtained. The present invention relates to a method for producing a graft copolymer, which comprises subjecting a monomer mixture consisting of the above to a graft reaction to give a molded article having an excellent balance of physical properties and an excellent chemical resistance.

[0002]

2. Description of the Related Art Conventionally, rubber-reinforced styrene copolymers have been known as thermoplastic resins having good moldability and excellent physical properties, and they are used for electric appliances, automobiles and other parts, and housings. It is widely used as a material for

A typical example of such a rubber-reinforced styrenic copolymer is called ABS resin, and typically acrylonitrile (A) and styrene (S) are emulsified in a polybutadiene (B) latex. It is one obtained by polymerizing and partly graft-copolymerizing it with polybutadiene.

However, ABS resin, for example, usually has a lower content of acrylonitrile component than that of styrene component, so that it is inferior in properties such as chemical resistance and gas barrier property.

In order to obtain a resin having these excellent properties, A
There is known a method for producing a graft copolymer in which the blending ratio of the acrylonitrile component in the BS resin is increased (see, for example, Japanese Patent Application Laid-Open No. 47-5594). Means are effective as such.

However, due to the widespread use requiring chemical resistance and gas barrier properties, the use of only high nitrile causes problems such as whitening and cracks during use due to lack of chemical resistance and impact resistance. Some things that cause

Conventionally, as a means for improving the chemical resistance, it has been made high nitrile, but it can be said that an attempt to further improve the chemical resistance of the high nitrile resin has not been made so far.

[Summary of Invention]

SUMMARY OF THE INVENTION The present invention aims to provide a solution to the above-mentioned problems, and an object of the present invention is to achieve this object by adopting a specific two-step polymerization method. That is, the method for producing a graft copolymer of the present invention is characterized by carrying out the following Step 1 and Step 2.

Step 1: A conjugated diene rubber latex (A) obtained by emulsion polymerization of a mixture of 50% by weight or more of a conjugated diene monomer and 50% by weight or less of an ethylenically unsaturated monomer copolymerizable therewith. ) Is 20 to 9 in terms of solid content
In the presence of 5 parts by weight, an ester compound of a monohydric alcohol having 2 to 12 carbon atoms and acrylic acid 70 to 99.
2% by weight, 0 to 27% by weight of a vinyl monomer copolymerizable with the acrylic ester, and a polyfunctional vinyl monomer of 0.
A step of emulsion-polymerizing 5 to 80 parts by weight of the monomer mixture (B) of 08 to 3% by weight (the total of A and B is 100 parts by weight), step 2: formation after the step 1 is completed In the presence of 10 to 70 parts by weight of latex as a solid content, 50 to 85% by weight of vinyl cyanide monomer and 15 to 5 of aromatic vinyl monomer.
A step of emulsion-polymerizing 30 to 90 parts by weight of a monomer mixture of 0% by weight (the total of the latex solid content and the monomer is 100 parts by weight).

<Effect> The graft copolymer resin composition obtained by the method for producing a graft copolymer according to the present invention is
Good chemical resistance. In addition, the impact resistance and fluidity are also good, and the balance of physical properties is excellent.

[Detailed Description of the Invention] The present invention is characterized mainly in that the graft copolymerization is carried out in two steps. Incidentally, the graft copolymerization corresponds to the polymerization of the monomer for the “branch” polymer in the presence of the polymer for the “stem” polymer, and thus the “branch” which was not “grafted” on the resulting polymer. Since it is unavoidable that a polymer of a monomer for a polymer coexists, "graft copolymer" and "graft copolymer" in the present invention include such a mixture and its production. .

<Step 1> Step 1 is a step of emulsion-polymerizing a monomer mainly composed of an acrylate monomer in the conjugated diene polymer latex. (1) Conjugated diene rubber latex (A) In the present invention, the conjugated diene rubber is obtained by polymerizing 50% by weight or more of a conjugated diene monomer and 50% by weight or less of a comonomer by an emulsion polymerization method. It is a synthetic rubber latex. Examples of the conjugated diene monomer that should give the conjugated diene rubber include 1,3-butadiene, isoprene and chloroprene. From the viewpoint of easy availability and polymerizability, 1,3-butadiene and isoprene are preferable. These may be used alone or in combination. Examples of the comonomer include unsaturated nitrile, unsaturated carboxylic acid ester, aromatic vinyl, vinyl pyridines and the like. These can be used alone or within each group and / or
You may use together between each group. As a specific example,
(A) unsaturated nitrile, such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, etc., preferably acrylonitrile, methacrylonitrile, acrylonitrile, among others, (b) unsaturated carboxylic acid ester, such as methyl acrylic acid or methacrylic acid, C ₁ -C ₆ alkyl esters such as ethyl, propyl and butyl, preferably methyl acrylate, ethyl acrylate,
Methyl methacrylate, ethyl methacrylate, (c) aromatic vinyl, nucleus and / or side chain substituted styrene (substituent is a lower alkyl group, halogen atom, lower alkoxy group, etc.), for example, styrene, α-methylstyrene, There are vinyltoluenes, vinylxylenes and the like, preferably styrene, (d) vinylpyridine, such as 4-vinylpyridine.

The content of the conjugated diene rubber as a solid content in the latex is usually about 10 to 60% by weight, preferably about 15 to 50% by weight. The particle size of the conjugated diene rubber is about 0.05 to 0.5 μm, preferably 0.1 to 0.4, as the weight average particle size measured by Nanosizer (light scattering method) manufactured by Coulter, Inc., USA.
It is usually about μm. When the conjugated diene rubber latex from the polymerization step does not have a desired rubber particle size, it may be adjusted to a desired particle size by a so-called “particle size enlargement method” known per se.

(2) Acrylic ester, etc. (B) Monomer (B) for "branch" polymer of graft copolymerization in step 1
Is mainly composed of acrylic acid ester. In the present invention, the acrylic ester is suitably an ester of acrylic acid and a monohydric alcohol having 2 to 12 carbon atoms, preferably 4 to 8 carbon atoms. Specifically, butyl acrylate, 2-ethylhexyl acrylate and the like are preferable.
When the carbon number is out of the above range, sufficient rubber elasticity cannot be obtained, which is not preferable. These esters may be used alone or in combination of two or more.

The vinyl monomer copolymerizable with the acrylic acid ester preferably has a function of improving and improving the properties of the acrylic rubber obtained by copolymerization as a reinforcing rubber and the graft polymerization reactivity. Specific examples thereof include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, p-vinyltoluene and other vinyltoluenes, alkyl methacrylate, 2-chloroethyl vinyl ether, vinyl monochloroacetate, and methoxyethyl acrylate. As the polyfunctional vinyl monomer, that is, a monomer having a plurality of ethylenically unsaturated bonds, divinylbenzene, ethylene glycol dimethacrylate, diallylmaleate, triallyl cyanurate,
Examples thereof include triallyl isocyanurate, diallyl phthalate, trimethylolpropane triacrylate, and allyl methacrylate. The use of these polyfunctional vinyl monomers facilitates intermolecular crosslinking of the acrylic acid ester copolymer, graft bonding with the matrix, etc., and improves the impact resistance of the composition involved in this reaction.

(3) Graft Copolymerization The graft copolymerization in step 1 can be carried out by a method known per se (for details, see the explanation of step 2). In the present invention, the solid content of the conjugated diene rubber latex (A), which is a "stem" polymer, is 2
0 to 95 parts by weight, preferably 20 to 80 parts by weight, and 5 to 80 parts by weight, preferably 20 to 80 parts by weight of the monomer (B) for the "branched" polymer such as acrylate ester ( However, it must be A + B = 100 parts by weight).
If A is less than 20 parts by weight, the predetermined impact resistance cannot be realized,
On the other hand, if it exceeds 95% by weight, the desired chemical resistance cannot be realized.

In the method of the present invention, it is desirable that the particle size after the graft polymerization in step 1 is 0.10 to 0.50 μm, preferably 0.10 to 0.40 μm. When the particle size is, for example, a small particle system having a particle size of less than 0.10 μm, the moldability (flowability) in molding the final product is reduced, and more important impact resistance is reduced. Therefore, the rubber addition efficiency is deteriorated. On the other hand, in the case of a large particle type having a particle size of, for example, more than 0.50 μm, it is not preferable because emulsion destabilization causes destabilization of the latex, which causes a problem such as an increase in the amount of scale during the polymerization. Such a latex having a relatively large particle size after the graft polymerization of the acrylic acid ester monomer may be used for a latex having a small particle size after the graft polymerization of the acrylic acid ester monomer, or a graft of the acrylic acid ester monomer. The conjugated diene rubber latex before polymerization may be obtained by performing an operation of particle size enlargement in order to obtain a target particle size.

The particle size enlargement is carried out by a known method, for example, a method in which the latex is once frozen and then redissolved, a method in which a mineral acid, an organic acid or the like is added to the latex to temporarily lower the latex pH, A method of applying shearing force to latex (Japanese Patent Laid-Open No. 54-133588, Japanese Patent Laid-Open No. 59-20).
No. 2211). In particular, the method of adding phosphoric acid or acetic anhydride to the latex is preferable because the particle size can be easily adjusted.

The particle size is preferably within the above range, but the particle size distribution after graft polymerization of the acrylic acid ester monomer need not be so-called monomodal with a single peak in the particle size distribution curve. Instead, it may be a bimodal having a plurality of mountains, for example, two mountains. In the case of a bimodal particle size distribution, the weight average particle size of both latexes may be in the range of 0.10 to 0.50 μm.

<Step 2> Step 2 is a step of emulsion-polymerizing a vinyl cyanide monomer and an aromatic vinyl monomer in the presence of the latex derived from Step 1. (1) Vinyl cyanide monomer In the present invention, specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile and α-chloroacrylonitrile. These may be one kind or a mixture of two or more kinds.

The proportion of vinyl cyanide monomer in the monomer mixture must be 50 to 85% by weight.
If it is less than 50% by weight, the desired physical properties such as chemical resistance cannot be imparted to the graft copolymer, which is not preferable. Particularly preferably, it is 50 to 70% by weight or more. Further, if it exceeds 85% by weight, properties of the graft copolymer such as molding processability and coloring property upon heating are deteriorated, which is not preferable.

(2) Aromatic Vinyl Monomer Specific examples of the aromatic vinyl monomer in the present invention include:
Unsubstituted or nucleus- and / or side-chain-substituted styrene (substituents are lower alkyl groups, halogen atoms, lower alkoxy groups, etc.), for example, styrene, α-alkylstyrene such as α-methylstyrene, p-methylstyrene, etc. And nuclei-substituted alkyl styrene, halogenated styrene, vinyl naphthalene, and the like. These may be one kind or a mixture of two or more kinds within each group and / or between each group. The proportion of the aromatic vinyl monomer in the monomer mixture should be 15 to 50% by weight. If the ratio is out of the above range, the properties of the resulting graft copolymer are unfavorable because the properties such as desired chemical resistance, gas barrier property, molding processability, and coloring property upon heating are deteriorated.

(3) Graft Copolymerization The graft copolymerization in step 2 can also be carried out by a method known per se. The proportion of the graft latex at the start of the step 2 should be 10 to 70 parts by weight, preferably 20 to 60 parts by weight (based on the total amount of the "branch" polymer monomer) as a solid content. . When the content is less than 10 parts by weight, the impact resistance of the resulting graft copolymer is lowered, and a molded article having the desired physical properties cannot be obtained, and the product is used as an impact resistance-imparting agent. Is not preferable because the effect is reduced. If the rubber solid content exceeds 70 parts by weight, the graft ratio of the resulting graft copolymer becomes small, and the dispersibility of the rubber particles and the rubber efficiency, that is, the impact resistance at the same rubber concentration, are unfavorable.

Through steps 1 and 2, the preferred graft copolymerization method of the present invention is about 0 to 0 with oxygen removed.
The monomers are separately or mixed at a temperature of about 100 ° C., and if necessary, components other than the monomers such as emulsifiers, dispersants, polymerization initiators, molecular weight regulators or chain transfer agents, p
The H-controlling agent and the like are supplied to the polymerization system as they are or in an emulsified state at a time, batchwise or continuously, and emulsion polymerization is carried out. Polymerization initiators (or catalysts) that can be used include persulfuric acid, peracetic acid, perphthalic acid and other peracid catalysts, potassium persulfate and other peracid catalysts, hydrogen peroxide, benzoyl peroxide, chlorobenzoyl peroxide. , Naphthyl peroxide, acetyl peroxide, benzoylacetyl peroxide, lauryl peroxide, di-t-peroxide
There are peroxide catalysts such as butyl, dicumyl peroxide, t-butyl peroxide and sodium peroxide, alkyl hydroperoxides such as t-butyl hydroperoxide, and azo catalysts such as azobisbutyronitrile. Or a mixture of two or more kinds can be used. These can also be used as a redox catalyst in combination with a reducing agent.

Emulsifiers that can be used in the present invention include fatty acid salts, rosin acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates. Examples thereof include potassium and sodium salts such as salts.

The chain transfer agent which can be used in the present invention is not particularly limited, and examples thereof include n-octyl mercaptan and n.
-Dodecyl mercaptan, t-dodecyl mercaptan,
Etc. or terpinolene, α-methylstyrene linear dimer, etc. are used. The polymerization product is obtained in the form of a latex, and the polymer is coagulated by a conventionally known method, for example, an agglomeration method with an electrolyte or a solvent, and further washed with water,
By appropriately combining the steps of drying, mixing, kneading, devolatilizing, pelletizing and the like, it can be used as a molding material. It is also possible to add plasticizers, stabilizers, lubricants, dyes and pigments, fillers and the like during the polymerization or after the polymerization as required.

<Produced Graft Copolymer> The graft copolymer produced by the combination of step 1 and step 2 is useful as a molding material because it has desired physical properties by itself. It can also be used as an impact resistance-imparting material by mixing with the thermoplastic resin.

[0028]

EXAMPLES The following examples and comparative examples serve to explain the present invention more specifically. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

In each of the following Examples and Comparative Examples, the physical properties of the impact resistant styrene resin are measured by the following methods. (1) Izod impact strength According to JIS K7110. (2) Melt flow rate Measured under the condition of 220 ° C./10 kg in accordance with JIS K7210, and expressed as the number of g flowing out for 10 minutes. (3) Average Particle Size of Latex The average weight particle size of latex was measured by "Nanosizer" manufactured by Coulter Co., USA. (4) Chemical resistance The final product was compression-molded into a dumbbell shape, and a rigid polyurethane foam was adhered by an in-situ foaming method using Freon 123 to obtain a test piece. The test piece was fixed to the jig while applying tensile strain at 23 ° C, and immediately, the jig together with -20 ° C.
After cooling and standing for 17 hours, the strain value in which crazes or cracks occurred after cooling and standing was measured. The larger the critical strain value in which these cracks occur, the better the chemical resistance is judged to be. The shape of the dumbbell is J
A thickness of 1 mm for a tensile test specified in IS-K6734 was used, and a rigid polyurethane foam was adhered to its parallel portion with a width of 10 mm, a length of 40 mm and a thickness of 10 m.

Example 1 (1) Production of Conjugated Diene Rubber (A) 2400 g of deionized water (hereinafter referred to simply as "water") in a 5 LSUS autoclave, higher fatty acid soap (sodium fatty acid containing 18 carbon atoms as a main component) (Salt) 64.0 g and sodium hydroxide 1.2 g were charged, and after nitrogen substitution, 68 ° C.
The temperature was raised to. 1,3-butadiene (BD) 1440 g,
After charging 321 g of a monomer mixture consisting of 160 g of styrene (St) and 4.8 g of t-dodecyl mercaptan, 2.16 g of potassium persulfate was added. Exothermic heat was generated in about several minutes, and the initiation of polymerization was confirmed. 1 hour after the addition of potassium persulfate 1284 g of the monomer mixture
Was continuously started and finished at 6 hours. After the addition of the monomer mixture, raise the temperature to 80 ° C and
Polymerization proceeded for a time. The obtained latex had a solid content concentration of 39.5% and an average particle size of 0.08 μm.

Into a 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer, and an auxiliary addition device, 2278 g of the above latex (solid content 900 g), 0.45 g of naphthalenesulfonic acid formalin condensate, and 290 g of water were charged. While stirring, the internal temperature was raised to 55 ° C. Subsequently, 6.3 g of acetic anhydride was added to 120 g of water, stirred for 30 seconds with a homogenizer, and added to this flask at the same temperature. 2 minutes after addition, naphthalene sulfonic acid condensate 4.5
g and 41 g of 10% by weight potassium hydroxide are added,
The particle size enlargement was completed. The obtained particle size enlarged latex is
The solid content concentration was 32.1%, and the average particle size was 0.12 μm.

(2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) 2804 g (solid content 900) of the latex of (1) above.
g), 291 g of water and 7.5 g of sodium hydrogen carbonate
Was charged into a 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer and an auxiliary agent addition device, and under a nitrogen stream,
The temperature was raised to 75 ° C. with stirring. Subsequently, 60 g of an aqueous solution of potassium persulfate (I) (containing 0.6 g of potassium persulfate) was added to this flask, and after 5 minutes, 570 g of butyl acrylate (BA) and acrylonitrile (AN) were added at the same temperature. ) 30 g and 2.1 g of allyl methacrylate (AMA) were continuously charged into the monomer mixture, which was completed at 3 hours and 30 minutes, but at 1 hour and 30 minutes and 2 hours and 30 minutes. At this point, an aqueous potassium (II) persulfate solution (containing 0.36 g of potassium persulfate) and an aqueous potassium (III) persulfate solution (containing 0.24 g of potassium persulfate) were added. After the addition of the monomer mixture was completed, the temperature was raised to 80 ° C., and the polymerization was further proceeded for 1 hour at the same temperature.

The obtained Step 1 latex had a solid content concentration of 36.3% and an average particle size of 0.18 μm.

(3) Preparation of Graft Copolymer 1791 g (solid content 650) of the latex of (2) above.
g), 13.0 g of sodium alkyldiphenyl ether disulfonate and 900 g of water (as a total water content)
Was charged into a 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer and an auxiliary agent addition device, and under a nitrogen stream,
The internal temperature was raised to 65 ° C with stirring.

Subsequently, an aqueous solution of potassium persulfate (I) (containing 0.98 g of potassium persulfate) was added to the flask.
100 g of acrylonitrile was added at the same temperature.
g, 260 g of styrene and 13.7 g of n-dodecyl mercaptan were added continuously to start the grafting reaction. From immediately after the reaction to 4 hours later, the monomer mixture was added to the polymerization system at a constant addition rate.
In addition, from 30 minutes to 4 hours and 30 minutes after starting the reaction, an aqueous potassium persulfate (II) solution (2.28 g
Including potassium persulfate. ) Was continuously added to the polymerization system at a constant addition rate of 230 g. After starting the reaction, 4
After the lapse of time, after the addition of the monomer mixture was completed, the reaction was further continued at the same temperature for 1 hour to complete the graft reaction. The solid content of the obtained latex (latex 2) was 34% by weight.

The graft copolymer latex obtained was added with 15 g of an antioxidant and then added to an aqueous magnesium sulfate solution heated to 95 ° C. with stirring to coagulate. The solidified product was washed with water and dried to obtain a white powdery resin composition having a high rubber content. The resin composition thus obtained was used as a styrene-acrylonitrile copolymer (AN / St weight ratio 60/40, melt flow rate 10 g / 10 minutes (220 ° C., 10 kg)) having the same composition except rubber. The content of the rubbery polymer in the entire composition was blended by using an extruder so as to be 20% by weight, pelletized, and then each test piece was prepared by injection molding. It was evaluated by the method. The results are as shown in Table 1.

Example 2 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). (3) Production of Graft Copolymer In the example described in Example 1 (3), the procedure was the same as that in Example (3) except that the composition of the monomer mixture was changed as follows. Monomer mixture acrylonitrile 520 g styrene 130 g n-dodecyl mercaptan 19.5 g The solid content concentration of the obtained latex was 34% by weight. The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Example 3 (1) Production of conjugated diene rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) In the example described in Example 1 (2), the conjugated diene rubber (A) and the acrylic acid ester monomer mixture (B) are used. The procedure was the same as in Example (2) except that the amount of was changed as shown below. Conjugated diene rubber (A) 2848.1 g (solid content 1125 g) Acrylic ester monomer mixture (B) BA 354.5 g AN 18.7 g AMA 1.8 g (total 375 g) Average particle size was 0.15 μm. .

(3) Preparation of Graft Copolymer Same as described in Example 1 (3). The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Example 4 (1) Production of conjugated diene rubber (A) The same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) In the example described in Example 1 (2), the conjugated diene rubber (A) and the acrylic acid ester monomer mixture (B) are used. The procedure was the same as in Example (2) except that the amount of was changed as shown below. Conjugated diene rubber (A) 949.4 g (solid content 375 g) Acrylic ester monomer mixture (B) BA 1063.4 g AN 56.0 g AMA 5.6 g (total 1125 g) Average particle size was 0.20 μm. . (3) Preparation of graft copolymer Same as described in Example 1 (3).

The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Example 5 (1) Production of conjugated diene rubber (A) The same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). (3) Production of graft copolymer 1791 g (solid content 650) of the latex of (2) above
g), 13.0 g of sodium alkyldiphenyl ether disulfonate and 900 g of water (as a total water content)
Was charged into a 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer and an auxiliary agent addition device, under a nitrogen stream,
The internal temperature was raised to 65 ° C with stirring.

While heating, 6.5 g of sodium pyrophosphate and 13.0 g of dextrose dissolved in 200 g of water
And 0.065 g of ferrous sulfate was added. When the temperature reached 65 ° C., 0.49 g of cumene hydroperoxide, 3.9 g of sodium alkyldiphenyl ether disulfonate and 95 g of water were added to this flask.
After 15 minutes, acrylonitrile 390g, styrene 26
The grafting reaction was initiated by the continuous addition of a monomer mixture of 0 g and 9.8 g of n-dodecyl mercaptan. From immediately after the reaction to 4 hours later, the monomer mixture was added to the polymerization system at a constant addition rate.

From the start of the reaction, 30 minutes to 4 hours and 30 minutes later, 2.28 g of cumene hydroperoxide, 9.1 g of sodium alkyldiphenyl ether disulfonate and 222 g of water were added over 4 hours. did. After the addition was completed, the reaction was further continued for 1 hour and cooled to complete the reaction.

The obtained graft polymer latex was coagulated by adding 15 g of an anti-aging agent to an aqueous magnesium sulfate solution heated to 95 ° C. with stirring. The solidified product was washed with water and dried to obtain a white powdery resin composition having a high rubber content. The resin composition thus obtained was added to a styrene-acrylonitrile copolymer (AN / St weight ratio 6
0/40, melt flow rate 10g / 10min (220
10 ° C.), and a rubber polymer in the whole composition so that the content thereof is 20% by weight by using an extruder, and after pelletizing, each test piece is prepared by injection molding. , Each physical property was evaluated. The results are as shown in Table 1.

Example 6 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). (3) Production of graft copolymer 1791 g (solid content 650) of the latex of (2) above
g), 13.0 g of sodium alkyldiphenyl ether disulfonate and 900 g of water (as a total water content)
Was charged into a 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer and an auxiliary agent addition device, under a nitrogen stream,
The internal temperature was raised to 65 ° C with stirring. While raising the temperature
6.5 g of sodium pyrophosphate dissolved in 200 g of water,
Dextrose 6.5 g and ferrous sulfate 0.065
g was added. When the temperature reached 65 ° C., 0.49 g of cumene hydroperoxide, 3.9 g of sodium alkyldiphenyl ether disulfonate and 95 g of water were added to this flask. After 15 minutes, continuous addition of a monomer mixture obtained by mixing 455 g of acrylonitrile, 151.7 g of styrene and 29.3 g of n-dodecyl mercaptan was started to start the graft reaction. 4 immediately after the reaction
Until the end of the hour, the monomer mixture was added to the polymerization system at a constant addition rate.

Then, immediately after the continuous addition of the above-mentioned monomer mixture was completed, 43.3 g of styrene was immediately added over 1 hour.
It was continuously added to the polymerization system. Also, after starting the reaction, 3
From 0 minute to 4 hours 30 minutes, 4.28 g of cumene hydroperoxide, 9.1 g of sodium alkyldiphenyl ether disulfonate and 222 g of water were added.
Added over time. After the addition of styrene was completed, the reaction was continued for another 1 hour and cooled to complete the reaction.

The obtained graft polymer latex was coagulated by adding 15 g of an antioxidant and then adding it to a magnesium sulfate aqueous solution heated to 95 ° C. with stirring. The solidified product was washed with water and dried to obtain a white powdery resin composition having a high rubber content.

The resin composition thus obtained was treated with a styrene-acrylonitrile copolymer (AN / St weight ratio 70/30, melt flow rate 10 g / 10 minutes (22
0 ° C., 10 kg)) and the content of the rubbery polymer in the total composition to be 20% by weight using an extruder, and after pelletizing, each test piece was prepared by injection molding. Then, each physical property was evaluated. The results are as shown in Table 1.

Example 7 (1) Production of conjugated diene rubber (A) Example 1 except that acetic anhydride was changed to 14.9 g and 10% by weight potassium hydroxide was changed to 96.9 g when the particle size was enlarged.
Same as described in (1). The average particle size was 0.35 μm. (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) A 5 L glass flask equipped with a stirrer, a reflux condenser, a thermometer, and an auxiliary additive device was placed in the latex 22 of (1) above.
78 g (solid content: 900 g), naphthalenesulfonic acid formalin condensate 0.45 g, and water 290 g were charged, and the internal temperature was raised to 55 ° C. while stirring. After this, Example 1
Graft polymerization of the acrylic acid ester monomer mixture was carried out in the same manner as described in (2). Average particle size 0.
It was 40 μm. (3) Preparation of graft copolymer Same as described in Example 1 (3).

Comparative Example 1 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) In the example described in Example 1 (2), the conjugated diene rubber (A) and the acrylic acid ester monomer mixture (B) are used. Was changed as shown below and no acrylic ester monomer mixture was used. Conjugated diene rubber (A) 1645.6 g (solid content 1500 g) Acrylate ester monomer mixture (B) 0.0 g (solid content 0 g) The average particle size was 0.12 μm. (3) Preparation of graft copolymer Same as described in Example 1 (3). The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Comparative Example 2 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) In the example described in Example 1 (2), the conjugated diene rubber (A) and the acrylic acid ester monomer mixture (B) are used. The amount was changed as shown below, and polymerization was carried out as follows without using the conjugated diene rubber. Conjugated diene rubber (A) 0.0 g (solid content 0 g) Acrylic ester monomer mixture (B) BA 1417.9 g AN 74.6 g AMA 7.5 g (total 1500 g) 2420 g of water in a 5 L glass flask, high-grade Fatty acid soap (sodium salt of fatty acid mainly having 18 carbon atoms) 3
2 g and 16 g of sodium hydrogen carbonate were charged, and the temperature was raised to 75 ° C. under a nitrogen stream. After adding 2.16 g of potassium persulfate, 5 minutes later, butyl acrylate (B
64 g of a monomer mixture consisting of 1520 g of A), 80 g of acrylonitrile (AN) and 8 g of methacrylic acid allyl ester (AMA) was charged. An exotherm occurred within a few minutes, confirming the initiation of polymerization. Twenty minutes after the initial charging of the monomer mixture, continuous addition of the remaining monomer mixture was started, and the addition was completed at 3 hours and 20 minutes. At the time of 2 hours and 30 minutes, 0.24 g of potassium persulfate was added. After the addition of the monomer mixture was completed, the temperature was raised to 80 ° C., and the polymerization was further continued at the same temperature for 1 hour. The obtained latex had a solid content concentration of 39.0% and an average particle size of 0.075 μm.

Then, a stirrer, a reflux condenser, a thermometer,
In a 5 L glass flask equipped with an auxiliary agent adding device, 2368 g of the above latex (solid content 900 g), 0.45 g of naphthalenesulfonic acid formalin condensate and water 2
00 g was charged, and the internal temperature was raised to 55 ° C. with stirring.

Subsequently, 6.3 g of acetic anhydride was added to 120 g of water, stirred for 30 seconds with a homogenizer, and added to this flask at the same temperature. Two minutes after the addition, 4.5 g and 10% by weight of naphthalene sulfonic acid condensate and 41 g of potassium hydroxide were added to complete the particle size enlargement. The obtained particle size enlarged latex has a solid content concentration of 32.1%,
The average particle size was 0.18 μm. (3) Preparation of graft copolymer Same as described in Example 1 (3). The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Comparative Example 3 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). (3) Production of Graft Copolymer In the example described in Example 1 (3), the procedure was the same as that in Example (3) except that the composition of the monomer mixture was changed as follows. Monomer mixture acrylonitrile 585 g styrene 65 g n-dodecyl mercaptan 19.5 g The solid content concentration of the obtained latex was 34% by weight. The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Comparative Example 4 (1) Production of Conjugated Diene Rubber (A) Same as described in Example 1 (1). (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). (3) Production of Graft Copolymer In the example described in Example 1 (3), the procedure was the same as that in Example (3) except that the composition of the monomer mixture was changed as follows. Monomer mixture acrylonitrile 195 g styrene 455 g n-dodecyl mercaptan 3.3 g The solid content of the obtained latex was 34% by weight. The results of measuring the physical properties of the graft copolymer are shown in Table 1.

Comparative Example 5 (1) Production of Conjugated Diene Rubber (A) Example 1 except that acetic anhydride was changed to 22.5 g and 10 wt% potassium hydroxide was changed to 146.3 g when the particle size was enlarged.
Same as described in (1). The average particle size was 0.62 μm. (2) Production of Graft Copolymer of Acrylic Ester Monomer Mixture (B) Same as described in Example 1 (2). Average particle size is 0.6
It was 5 μm. (3) Preparation of graft copolymer Same as described in Example 1 (3).

[0058]

[Table 1] As shown in Table 1, the graft copolymer resin composition which does not satisfy the conditions specified in the present invention has any physical properties, particularly chemical resistance and / or impact resistance and / or resin resistance of the molded article. Flowability is unsatisfactory, in other words, the graft copolymer resin composition according to the present invention is excellent particularly in chemical resistance and / or impact resistance of molded articles and / or fluidity of resin. That is, it is clear that the balance of physical properties is excellent.

[0059]

Industrial Applicability According to the present invention, a graft copolymer having good chemical resistance, good impact resistance and good fluidity and a good balance of physical properties can be obtained. This is as described above in the section.

Claims (2)

[Claims] 1. A process for producing a graft copolymer, which comprises carrying out the following steps 1 and 2. Step 1: Solidified conjugated diene rubber latex (A) obtained by emulsion-polymerizing a mixture of 50% by weight or more of a conjugated diene monomer and 50% by weight or less of an ethylenically unsaturated monomer copolymerizable therewith. 70 to 99.2% by weight of an ester compound of a monohydric alcohol having 2 to 12 carbon atoms and acrylic acid in the presence of 20 to 95 parts by weight in terms of minutes, a vinyl copolymerizable with the acrylic ester. Monomer 0-2
7% by weight and 5 to 80 parts by weight of a monomer mixture (B) of 0.08 to 3% by weight of a polyfunctional vinyl monomer (the total of A and B is 100 parts by weight). Step of emulsion polymerization, Step 2: After the completion of Step 1, in the presence of 10 to 70 parts by weight of the produced latex in terms of solid content, vinyl cyanide monomer 50 to 85% by weight and aromatic vinyl monomer 15 to 5
A step of emulsion-polymerizing 30 to 90 parts by weight of a monomer mixture of 0% by weight (the total of the latex solid content and the monomer is 100 parts by weight). 2. The method for producing a graft copolymer according to claim 1, wherein the average particle size of the latex after emulsion polymerization in step 1 is 0.10 to 0.50 μm.