JPS6218414A - Production of vinyl aromatic resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled, rubber-containing resin excellent in gloss, impact resistance, etc., by mixing a specified graft polymer with a rubber containing a diene rubber and a vinyl aromatic monomer, adding an unsaturated dicarboxylic acid anhydride to the mixture and polymerizing the monomers. CONSTITUTION:A graft copolymer having 50-85wt% polymer main chain containing at least 50wt% butadiene units, having 40-5wt% methacrylate ester side chains grafted upon the main chain, and having styrene side chains graft- polymerized upon the main chain is prepared. This copolymer is mixed with 2-25wt% diene rubber and 98-75wt% vinyl aromatic monomer (e.g., styrene) and further mixed with an unsaturated dicarboxylic acid anhydride (e.g., maleic anhydride), and the polymerization of the resulting mixture is continued to a conversion of the vinyl aromatic monomer of 30-80wt% to obtain the titled composition containing a rubber in a dispersion state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a vinyl aromatic resin composition, and more specifically, a method for producing a vinyl aromatic resin composition that has excellent gloss, impact resistance, and heat resistance. The present invention relates to a method for producing a resin composition.

[Prior art and its problems] Conventionally, styrene-maleic anhydride copolymer (SMA) has been used as various industrial materials due to its excellent heat resistance. , improvement in impact resistance is desired.

Japanese Patent Publication No. 55-7849 discloses that butadiene rubber is dissolved in styrene and copolymerization with maleic anhydride is initiated.
A method for producing a composition comprising rubber particles containing adsorbed copolymer dispersed in a copolymer matrix is disclosed.

However, this method has a problem in that it is not possible to obtain a composition that is excellent in both gloss and impact resistance.

On the other hand, Japanese Patent Publication No. 59-13541 discloses a composition in which an MBS resin prepared by an emulsification method is blended with SMA.

However, this composition still has insufficient impact resistance.

This invention has been made based on the above circumstances.

That is, an object of the present invention is to solve the above-mentioned problems and provide a method for producing a resin composition that has gloss, impact resistance, and heat resistance so that there are no practical problems. .

[Means for solving the above problems] The outline of the present invention for solving the above problems is to combine a graft copolymer having a specific structure, a diene rubber, and a vinyl aromatic monomer in a specific blend. Mix in composition and then
An unsaturated dicarboxylic anhydride is mixed into this mixture, and the resulting mixture is heated until a predetermined conversion rate of the vinyl aromatic monomer is reached.

It polymerizes.

More specifically, in the presence of rubber, vinyl aromatic resin is copolymerized with an unsaturated dicarboxylic acid anhydride to form a vinyl aromatic resin group containing rubber in a dispersed form. In the manufacturing method, the rubber has a polymer main chain (a) containing not less than 50% butadiene units in an amount of 50 to 85%.

The methacrylic acid ester side t7o (b) obtained by graft polymerization of this polymer to the button (a) is 40 to 5 ton %, and.

A graft copolymer and diene rubber having 0 to 40% by weight of styrene side chains (c) graft-polymerized to this polymer weight jO(a) and 2 to 20%
After mixing the vinyl aromatic monomer with 98 to 75% by weight, unsaturated dicarboxylic acid anhydride is added, and the conversion rate of the vinyl aromatic monomer is 30 to 80% by weight. % of the copolymerization reaction.

The graft copolymer has 53 butadiene units.
The polymer weight fi (a) contains a methacrylic acid ester side E (b) and a styrene side chain (C).

The polymer weight m(a) is 50 tons% of butadiene units.
Therefore, the graft copolymer of the present invention may have a polymer main chain containing 100% butadiene units.

It may also be a polymer main chain containing 50% by weight or more of butadiene units and less than 50% by weight of other vinyl monomers; if the butadiene units are less than 50% by weight, , impact resistance decreases. Examples of the vinyl monomer include styrene and methacrylic acid ester.

Single X5 constituting methacrylic acid ester side ff1(b)
Examples of methacrylic esters include methyl methacrylate and ethyl methacrylate.

There are no particular limitations on styrene as a monomer constituting the styrene side chain (C).

In this invention, the structure of the graft copolymer has a width of butadiene; % or more, preferably 70 weight tons
The polymer weight j13 (a) contained in % is 50 to 85 beads e
%, preferably 65 to 80 ton V%, the methyl methacrylate side chain (b) graft-polymerized to this polymer main chain (a).
) at 40-5%.

Preferably 20 = l Oi'173%, and
This polymer FE has a styrene side chain (c) graft-polymerized on the button (a) in an amount of 0 to 40%, preferably 0 to 2%.
It is desirable to have it at 0%.

The content of the polymer main chain (a) is less than 50% by weight, and the content of methacrylic acid ester side ff1 (b) is 40%.
Does it exceed heavy hardness X or contain styrene side chains (c)? is 40
If it exceeds %, the graft copolymer will have too much polymethacrylic acid ester or polystyrene properties, making it impossible to achieve the object of the present invention, or conversely, the polymer main chain (a) If the content exceeds 85% by weight and the content of the polymethacrylic acid ester side chain (b) is less than 5% by weight, the properties of polybutadiene will be too pronounced and the object of the invention cannot be achieved.

Such a graft copolymer is produced by emulsion polymerizing butadiene in a conventional manner in the presence of a crosslinking agent such as ethylene dimethacrylate, divinylbenzene, etc. added as necessary, and adding methacrylic acid ester and methacrylate to the resulting polymer latex. It can be obtained by adding styrene and carrying out emulsion copolymerization by a conventional method. The graft copolymer may be produced by a one-step method in which a methacrylic ester and styrene are simultaneously blended into a polymer latex and graft copolymerized, or a methacrylic ester and a styrene are blended into the polymer latex and one of the methacrylic ester and styrene is blended into the polymer latex. Alternatively, a multi-stage method may be used in which either methacrylic acid ester or styrene is graft copolymerized, and then the remaining heptamer of methacrylic acid ester and styrene is graft copolymerized.

Examples of the diene rubber include butadiene rubber,
Examples include isoprene rubber, chloroprene rubber, styrene-butadiene rubber, butadiene-acrylonitrile rubber, styrene-butadiene-styrene rubber, etc. These rubbers can be used alone, or two or more rubbers can be mixed. You can also use Among these various rubbers, butadiene rubber, styrene-butadiene rubber, and styrene-butadiene-styrene rubber are preferred.

As described above, the present invention has the advantage of using a graft copolymer having a specific structure and a diene rubber.

Examples of the vinyl aromatic monate include styrene, α-methylstyrene, dimethylstyrene, diethylstyrene, vinyltoluene, impropenylbenzene,
Examples include monochlorostyrene, dichlorostyrene, vinylxylene, ethylvinylxylene, and the like. Among these, preferred are styrene, α-methylstyrene, and vinyltoluene.

Examples of the unsaturated dicarboxylic anhydride include maleic anhydride, itaconic anhydride, oxymaleic anhydride, citraconic anhydride, phenylmaleic anhydride, aconitic anhydride, ethylmaleic anhydride, chloromaleic anhydride, and the like. It will be done. Among these, maleic anhydride is preferred.

The method of the present invention includes blending the graft copolymer, the diene rubber, the vinyl aromatic monomer, and the unsaturated dicarboxylic acid anhydride in a specific ratio, and then converting the vinyl aromatic monomer. The polymerization reaction is carried out until the percentage is 30-80% by weight.

That is, first, 25 to 2% by weight of the graft copolymer and diene rubber, preferably 15 to 4.5% by weight of the graft copolymer, and 5 to 0.0% of the diene rubber.
5% by weight and 75-98% by weight of the vinyl aromatic compound;
Preferably, 80 to 95% of balls are mixed. This mixture is a mixture of the vinyl aromatic monomer in which the diene rubber is dissolved and the graft copolymer, to which an unsaturated dicarboxylic acid anhydride is further added, and then the vinyl aromatic monomer is The polymerization reaction is carried out until the conversion rate of the polymer reaches 30 to 80% by weight.

When the blending ratio of the graft) F:TC combination and diene rubber is more than 25 tons:6%, a vinyl aromatic resin composition with sufficient heat resistance cannot be obtained even by the production method of the present invention. Furthermore, if the blending ratio of the graft copolymer and diene rubber is less than 2%, a vinyl aromatic resin composition with sufficient impact resistance cannot be obtained.

Furthermore, it is not preferable from the viewpoint of productivity to stop the polymerization reaction before the conversion rate of the vinyl aromatic monomer reaches 30% by weight, and the conversion rate becomes much higher than 80% by weight. Continuing the polymerization reaction until this point is undesirable because the system becomes highly viscous, the reaction becomes non-uniform, and the physical properties of the resulting vinyl aromatic resin composition deteriorate.

The mixing and polymerization reaction may be carried out in a single reaction tank or in a multi-stage continuous process in which a plurality of tanks are arranged in series, but from a technical standpoint, it is usually
Alternatively, the latter three-stage process is preferred.The polymerization tank used may be one ordinary polymerization tank, and a complete mixing type is particularly preferred, and a tank equipped with, for example, double helical blades and a Crawford Russell structure is preferable. .

When employing such a multi-stage continuous process, especially a two-stage continuous process, the graft copolymer, 25 to 2% of the diene rubber, and a vinyl aromatic monomer are added to the first polymerization tank in the first stage. Firstly, 75 to 98 tonne weight% of the vinyl aromatic monomer was charged and mixed by stirring.Next, unsaturated dicarboxylic acid anhydride was added to this first polymerization tank, and the conversion rate of the added vinyl aromatic monomer was The polymerization reaction is carried out until the amount becomes 15 to 40% by weight.

Thereafter, the entire amount of the polymerization reaction product is transferred from the first combining tank to the second combining tank in the second stage, and unsaturated dicarboxylic acid anhydride is charged into this second polymerization tank, and the vinyl aromatic monomer is It is preferable to carry out the polymerization reaction until the conversion rate of polymer becomes 40 to 80% by weight.

In this two-stage continuous process, the polymerization reaction may be carried out by either bulk polymerization or solution polymerization, but bulk polymerization is preferred since it eliminates the need for recovery and separation of the solvent.

Polymerization is usually carried out at 50 to 200°C, preferably 60 to 18°C.
It is carried out at a temperature of 0°C.

In starting the polymerization reaction, for example, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxide, t-
Butyl peroxybenzoate, dicumyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, diisopropyl peroxydicarponate, t-butyl peroxybivalate, stearoyl peroxide, azobissuine butyronitrile, 1.1 -bis-(t-butylperoxy)-1,
3,5-1-limethylcyclohexane, 1,1-bis-(
t-butylperoxyoctane), n-butyl-4,4
-bis-(t-butylperoxy)valerate, 2,2
Polymerization initiators such as -bis-(t-butylperoxy)butane, di-t-butylciba-oxyisophthalate, 2,5-dimethyl-di(benzoylperoxy)hexane may be added.

After the polymerization reaction is completed, the polymerization reaction product is usually transferred from the polymerization tank to a degassing tank, and unreacted vinyl aromatic monomer is recovered by degassing, and if a solvent is used, the solvent is also recovered. Thus, a vinyl aromatic resin composition is obtained.

The resulting vinyl aromatic resin composition is compounded as a rubber into a copolymer of a vinyl aromatic monomer and an unsaturated dicarboxylic anhydride, such as a copolymer of styrene and maleic anhydride (SMA). The graft copolymer and SM
It is assumed that the composition is a dispersed diene rubber that absorbs and contains A, but in some cases, it may be a graft copolymer in which styrene is further added to the graft copolymer to extend the side chain, or a styrene monomer. It is also possible that it contains polymers and the like. In any case, among the vinyl aromatic resin compositions obtained by the method of the present invention, the graft copolymer is preferably lθ to 35% by mass, particularly 15 to 30r.
f: % by weight, diene rubber is 1 to 15% by weight, especially 1 to 15% by weight
9% by weight, styrene simple unit is 70-98 mol%,
In particular, 72 to 95 mol%, with a median maleic anhydride content of 2 to 3
0 tons! 11%, especially 5 to 28 mol% of SMA.
A vinyl aromatic resin composition containing 15% to 90 tons, particularly 70 to 85 tons ψ%, is preferred in terms of gloss, impact resistance, heat resistance, and the like.

Through the above process, it is possible to obtain a vinyl aromatic resin composition with excellent gloss, impact resistance, heat resistance, etc., but in order to obtain a vinyl aromatic resin composition with further improved impact resistance. is an organic polysiloxane having a repeating center represented by the following general formula: is preferable.

The organic polysiloxane may be a homopolymer type organic polysiloxane in which the repeating unit is one type, or a random type, block type, or graft type copolymerization type in which the repeating unit is a combination of two or more types. It may be an organic polysiloxane. Furthermore, in the present invention, a part of the organic groups of these organic polysiloxanes may be substituted with a hydroxyl group, an alkoxy group, a hydroxyalkyl group, or a polyhydroxyalkylene group. The organic polysiloxane may be used not only as a single type but also as a mixture of two or more types.

Examples of the organic polysiloxane include dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and the like, with dimethylpolysiloxane being particularly preferred. The viscosity of this organic polysiloxane is not particularly limited, but is usually 10 to 100.
000 c S t (30°C), preferably 30-2
000 cSt (30°C), where the viscosity at 30°C is less than 10 cSt because it is highly volatile.
Molded products tend to have poor appearance, and those with a viscosity of more than 100.000 cSt at 30°C are not preferred because they are difficult to mix uniformly into the vinyl aromatic resin composition.

The organic polysiloxane is usually blended in an amount of 1 part, preferably 0.02 to 0.2 parts f, per 100 parts f of the vinyl aromatic resin composition. This 41 polysiloxane may be added to the polymerization process in advance, or may be added after the polymerization is completed.

Furthermore, in the method of the present invention, additives such as hindered phenol-based and phosphorus-based antioxidants and flame retardants may be added before and after polymerization.

The vinyl aromatic resin composition produced by the method of this invention has excellent gloss, impact resistance, heat resistance, etc., and is therefore suitable for use in home appliances and interior and exterior parts of automobiles by extrusion molding, injection molding, etc. It is a useful resin composition that is suitably used in a wide range of fields such as the food field, medical field, and daily necessities and miscellaneous goods fields.

[Effect of the invention] According to the present invention, a graft copolymer having a specific structure, a diene rubber, a vinyl aromatic monomer, and an unsaturated dicarboxylic acid anhydride are mixed in a specific composition and in a specific blending order. Since the polymerization reaction is carried out after blending, it is possible to produce a vinyl aromatic resin composition that has excellent gloss, impact resistance, and heat resistance.

[Example] Next, examples and comparative examples of the present invention will be shown.

(Examples 1 to 4) As shown in Figure 1, the capacity 1 with double helical wings
．． A first polymerization tank 1 with a capacity of 81 and a second polymerization tank 2 with a capacity of 2.31, which is also equipped with double helical blades, are arranged in series and connected to each other by a transfer pipe. Rubber mixing 4P before! 3 were arranged and bonded to each other.

In this rubber mixing tank 3, 87 to 89.5% by weight of styrene and MBS resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name "Metablen C-223J") powder as a graft copolymer l□
m (-% and butadiene rubber (manufactured by Asahi Kasei Corporation, trade name rNF-55ASJ styrene solution viscosity 150c
p) Mix 3-Q, 5@j 5% and silicone oil o, o 5%, and apply this mixture to the first
Simultaneously with supplying maleic anhydride to polymerization tank 1 at the flow rates shown in Table 1, the mixture is heated to 105 to 135°C so that the styrene in this first polymerization tank 1 has a conversion rate shown in Table 1. The polymerization reaction was carried out up to this point.

Next, the reaction product liquid in the first iT (gold type L) was transferred as it was into the second polymerization tank 2, and at the same time, maleic anhydride was supplied into the second polymerization tank 2 at the flow rate shown in Table 1. 1
The polymerization reaction was carried out while heating at 35 to 155° C. until the styrene in the second combining tank 2 reached the conversion rate shown in Table 1.

After the polymerization reaction, the reaction product liquid led out from the second polymerization tank 2 was passed through a degassing tank 4 to remove unreacted substances from a line 5, and then extruded from a vented extruder 6 to obtain pellets. This pellet was injection molded to prepare a test piece.

For each test piece, the melt index, gloss, Izot impact strength, and heat distortion temperature were measured according to the following specifications. The results are shown in Table 1.

Gloss: Conforms to JIS K 7015 Izo impact strength: Conforms to JIS K 7110 (notched) Heat distortion temperature: Conforms to JIS K 7207 (load 1
8.5K g/c, heating rate 2°C/min) (Examples 5 to 9) Same as Examples 1 to 4 except that silicone oil was not mixed during polymerization and was mixed after degassing after polymerization. The same procedure was carried out. The results are shown in Table 1.

(Example 10) The same procedure as in Example 1 was carried out except that zircon oil was not used. The results are shown in Table 1.

(Comparative Example 1.2) The same procedure as in Example 1 was carried out except that MBβ resin and silicone oil were not used. The results are shown in Table 1.

(Comparative Examples 3 to 6) Comparative Examples 3 to 6 were carried out in the same manner as in Example 1 except that the blending composition of MBS resin, butadiene rubber, styrene, and maleic anhydride was changed. The results are shown in Table 1.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a two-stage continuous process as an example of implementing the method of Part II. 1...First mixing tank, 2...Second mixing tank, 3...Rubber mixing tank, 4...Deaeration tank. Patent applicant: Idemitsu Petrochemical Co., Ltd. Figure 1

Claims (1)

[Claims] A method for producing a vinyl aromatic resin composition containing rubber in a dispersed state by copolymerizing a vinyl aromatic monomer and an unsaturated dicarboxylic acid anhydride in the presence of rubber. The rubber is a polymer main chain (a) containing 50% by weight or more of butadiene units.
) in an amount of 50 to 85% by weight, 40 to 5% by weight of a methacrylic acid ester side chain (b) grafted onto this polymer main chain (a), and graft polymerized onto this polymer main chain (a). Graft copolymer and diene rubber containing 0 to 40% by weight of styrene side chains (c)
After mixing with 98 to 75 weight % of vinyl aromatic monomer at a blending ratio of 98 to 75 weight %, unsaturated dicarboxylic acid anhydride is added, and the conversion rate of the vinyl aromatic monomer is 30 to 80 weight %.
1. A method for producing a vinyl aromatic resin composition, characterized by continuing a polymerization reaction until .