JPS6218413A - Production of vinyl aromatic resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled rubber-containing resin composition excellent in gloss, impact resistance, heat resistance, etc., by mixing a graft copolymer rubber of a specified composition with 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 eater side chains grafted upon the main chain, and having styrene side chains graft- polymerized upon the main chain is prepared. 2-25wt% this graft copolymer is mixed with 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. The present invention relates to a method for producing an aromatic resin composition.

[Prior art and its problems] Conventionally, styrene-maleic anhydride copolymer (SMA) has been used as a variety of industrial materials due to its excellent thermal properties. , improvements in impact resistance are desired.

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

However, this method has a problem in that it is not possible to obtain a composition that is excellent in both gloss and 1tifi resistance.

On the other hand, in Japanese Patent Publication No. 59-13541, MBS resin produced by emulsion polymerization is blended with SMA! [I acids are disclosed.

However, the impact resistance of this composition is still not 70%.

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 to provide a method for producing a resin composition that has gloss, impact resistance, and heat resistance so that there are no practical problems. be.

[Means for solving the above problems] The outline of the present invention for solving the above problems is to mix a graft copolymer having a specific structure and a vinyl aromatic monomer in a specific composition. Thereafter, an unsaturated dicarboxylic anhydride is mixed into this mixture, and the resulting mixture is polymerized as described above until a predetermined conversion rate of the vinyl aromatic monomer is reached.

More specifically, in the presence of rubber, vinyl aromatic Qt
In a method for producing a vinyl aromatic resin composition containing rubber in a dispersed state by copolymerizing a monomer and an unsaturated dicarboxylic acid anhydride, the rubber contains 50% or more of butadiene units. - Polymer containing side chains (a) of 50 to 85 l permissible%, and.

This polymer tJ) (a) has a styrene side chain (c) that is combined with graph 1 in an amount of θ~40 tons-%.

A graft copolymer having 2 to 25% of the vinyl aromatic mass is mixed with 98 to 75% of the vinyl aromatic mass, and then an unsaturated dicarboxylic acid anhydride is added, and the vinyl aromatic mass of the vinyl aromatic mass is added. This method of producing a vinyl aromatic resin composition is characterized in that the polymerization reaction is continued until the conversion rate is 30 to 80% by weight.

The graft copolymer contains 50% butadiene units.
The above polymer has a methacrylic acid ester side jO(b) and a styrene side chain (C) on E(a).

Since the tO(a) on this polymer only needs to contain 50% or more of butadiene moieties, the graft copolymer of the present invention may have a polymer main chain containing 100% butadiene units. It's good.

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, or less than 50% by weight of butadiene units. As a result, impact resistance decreases. Examples of the vinyl monomer include styrene and methacrylic acid ester.

Examples of the methacrylic ester as a monomer constituting the methacrylic ester side chain (b) include methyl methacrylate and ethyl methacrylate.

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

In the present invention, the structure of the graft copolymer includes butadiene monomer in an amount of 50% by volume or more, preferably 70% by volume:
Polymer-r[)(a) containing IS% of 50 to 85 tons: methacrylic grafted to X1(a) on this polymer at S°%, preferably 65 to 80 tons. Acid methyl side chain (b) at 40 to 5%.

Preferably 20" I O balls Q%, and on this polymer jO (graph a) 1 combined styrene side chains (c
) in an amount of θ~40%, preferably 0~20@-1%.

The content of the polymer main chain (1): is less than 50% by weight, and the content of the methacrylic acid ester side chain (b) is 40%.
If the content of styrene side chains (c) exceeds 1% or 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.

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

Such a graft copolymer can be prepared by emulsifying 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 to the resulting polymer latex. It can be obtained by adding styrene and emulsifying the mixture by a conventional method. Graft copolymerization may be a one-step method in which methacrylic ester and styrene are simultaneously blended into a polymer latex and graft copolymerized, or one of methacrylic ester and styrene is blended into the polymer latex and methacrylic ester and styrene are blended. A multi-stage method may be used in which either styrene is graft copolymerized and then the remaining heptamers of methacrylic acid ester and styrene are graft copolymerized.

Examples of the vinyl aromatic monomer include styrene,
α-methylstyrene, dimethylstyrene, diethylstyrene, vinyltoluene, isopropenylbenzene, monochlorostyrene, dichlorostyrene, vinylxylene,
Examples include ethylvinylxylene. 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 is such that after blending the graft J (polymer, the vinyl aromatic monomer, and the unsaturated dicarboxylic acid anhydride in a specific ratio), the conversion rate of the vinyl aromatic monomer is 30. The polymerization reaction is carried out until the concentration is ~80 tons.

That is, first, 25 to 2% by amount of the graft copolymer,
Preferably 15 to 5 tonne % of the vinyl aromatic monohydric compound 7
5 to 98% by weight, preferably 80 to 95% by weight, are mixed, and an unsaturated dicarboxylic acid anhydride is further added to carry out a polymerization reaction.

If the amount of the graft copolymer is more than 25% by weight, a vinyl aromatic resin composition with sufficient heat resistance cannot be obtained even by the packaging method of the present invention, and the graft copolymer If the copolymer content is less than 2%, a vinyl aromatic resin composition with sufficient impact resistance cannot be obtained.

In addition, if the conversion rate of vinyl aromatic monomer is less than 30% by weight, productivity will decrease, and if the conversion rate exceeds 80% by weight, the system will become highly viscous and the reaction will be non-uniform. The physical properties of the composition deteriorate.

The mixing and polymerization reaction may be carried out in a bird reaction tank or in a multistage continuous process in which a plurality of tanks are arranged in series, but from an industrial point of view, it is usually carried out in 2 or 3 reactors. The latter stage process is preferred; the polymerization tank used may be one ordinary polymerization tank, particularly a complete mixing type, and preferably one equipped with, for example, a double helical or Crawford-Russell tank.

When employing such a multi-stage continuous process, especially a two-stage continuous process, 25 to 2% of the graft copolymer and 75 to 9% of the vinyl aromatic monomer are added to the 1st stage of the first mixing tank.
8 tons of +-% were first charged and mixed by stirring, and then an unsaturated dicarboxylic anhydride was added into the first mixing tank, and the total conversion rate of the added vinyl aromatic amount Ia was determined. 15~
The polymerization reaction is carried out until it reaches 4%.Then, the entire amount of the polymerization reaction product is transferred from the first combination tank to the second combination tank in the second stage 11, and unsaturated dicarbonate is further transferred to this second combination tank. When acid anhydride was charged, the conversion rate of 9 vinyl aromatic compounds was 40~40.
It is preferable to carry out the polymerization reaction until B □ (, IJ%).

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 peroxy dicarponate, t-butyl peroxy pivalate, stearoyl peroxide, azobis-isobutyronitrile, 1. l-bis-(t-butylperoxy)-1,
3,5-trimethylcyclohexane, l, ■-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.

At the end of the polymerization reaction, the polymerization reaction product is usually transferred from the polymerization tank to a degassing tank, and unreacted vinyl aromatic 1 is removed by degassing.
-j is collected, and when a solvent is used, the solvent is also collected to obtain a vinyl aromatic resin composition.

The resulting vinyl aromatic resin composition is a copolymer of a vinyl aromatic monomer and an unsaturated dicarboxylic anhydride, such as a copolymer of styrene and maleic anhydride (SMA).
It is presumed to be a composition in which the graft copolymer blended as a rubber is dispersed, but depending on the case, there may be a composition in which SMA is further grafted to the blended graft copolymer. In any case, among the vinyl aromatic resin compositions obtained by the method of this invention.

Is the graft copolymer lθ~35 times? %, especially 15~
30% fake, styrene monomer unit 70-98 mol%
, especially from 72 to 95 mol %, containing 2 to 95 mol % of maleic anhydride units.
65 to 30 mol% SMA, especially 5 to 28 mol%
A vinyl aromatic resin MI acid containing 90% by weight, particularly 70 to 85% by weight, is preferred from the viewpoint of gloss, impact resistance, heat resistance, etc.

In this way, 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. It is preferable to blend an organic polysiloxane having a repeating unit represented by the following general formula (wherein R1, 12 represents an alkyl group, an aryl group, or an aralkyl group).

The organic polysiloxane may be a homopolymer type organic polysiloxane in which the repeating unit is one type, or a random type, blow two type, or graft type Jt consisting of a combination of two or more types of repeating units. , ir (which may be a synthetic organopolysiloxane).In general, in the present invention, these organopolysiloxanes are partially substituted with a hydroxyl group, an alkoxy group, a hydroxyalkyl group, or a polyhydroxyalkylene group. These organic polysiloxanes may be used not only alone, but also as a mixture of two or more.

Examples of the organic polysiloxane include dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, and the like.
Dimethylpolysiloxane is preferred. The viscosity of this organic polysiloxane is not particularly limited, but is usually 10 to 10
0.000 c S t (30°C), preferably 30
~2000 cSt (30°C).Those with a viscosity of less than 10 cSt at 30°C are highly volatile and tend to have poor appearance when molded.
Those having a viscosity of more than 100.000 cSt at °C are not preferred because they are difficult to mix uniformly into the vinyl aromatic resin composition.

The amount of the organic polysiloxane to be blended is usually 1 part to 100 parts of the vinyl aromatic resin composition, preferably 0.02 to 0.2 parts by weight. This organic polysiloxane may be added in advance during polymerization or may be added after one 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, the medical field, and the field of daily necessities and miscellaneous goods.

[Effects of the Invention] According to the present invention, a graft copolymer having a specific structure, a vinyl aromatic system, an i monomer, and an unsaturated dicarboxylic acid anhydride are blended in a specific blending composition and in a specific blending order. Since the polymerization reaction is then carried out, a vinyl aromatic resin composition having excellent gloss, INIJ impact resistance and heat resistance can be produced.

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

(Examples 1 to 3) As shown in Figure 1, a container with a double helical size:
>The first combining tank 1 for S and SX and the second combining tank 2 with a capacity of 2 or 3 times, which is also equipped with a double helical size, are arranged in series and connected to the phase 〃 by a transfer pipe, Furthermore, a rubber mixing tank 3 was placed in front of this first polymerization tank 1 and connected to each other.

In this rubber mixing tank 3, 89.95% of styrene and 10 f of MBS resin (Mitsubishi Rayon Co., Ltd., trade name "Metablen C-223J") powder as a graft copolymer were added.
[1% of silicone oil and 0.05% of heavy water are mixed, and this mixture is supplied to the first polymerization tank 1 at a flow rate of IJI/hour, and at the same time the IR shown in Table 1, ? While supplying maleic anhydride, the polymerization reaction was carried out by heating to 105 to 135°C until the styrene in this first mixing tank reached the conversion rate shown in Table 1. Next, the first polymerization The reaction product liquid in tank 1 is transferred as it is into second polymerization tank 2, and at the same time, this second
Maleic anhydride was supplied into the polymerization tank 2 at the flow rate shown in Table 1, and the second polymerization tank 2 was heated to 135 to 155°C.
The polymerization reaction was carried out until the styrene contained therein 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: Compliant with JIS K 7015 Izot impact strength: JIS K 7110 (with notch)
Heat distortion temperature: According to JIS K 7207 (load ((
18.5 Kg/crn', heating rate 2°C/min) (Examples 4 to 8) Same as Examples 1 to 3 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 9.10) The same procedure as in Example 4 was carried out except that zircon oil was not used. The results are shown in Table 1.

(Comparative Examples 1 to 3) Instead of MBS resin, polybutadiene (manufactured by Asahi Kasei Corporation, product name "Asaprene 700AJ styrene solution viscosity 35
The same procedure as in Example 1 was carried out except that cp) was used. The results are shown in Table 1.

(Comparative Example 4.5) MBS resin? The same procedure as in Example 1 was carried out except that . The results are shown in Table 1.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a two-stage continuous process as an example of implementing the method of the present invention. 1... First polymerization tank, 2... Second polymerization 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). A graft copolymer having styrene side chains (c) in an amount of 0 to 40% by weight is mixed with 98 to 75% by weight of a vinyl aromatic monomer in a proportion of 2 to 25% by weight, and then an unsaturated dicarboxylic acid is added. A method for producing a vinyl aromatic resin composition, which comprises adding an anhydride and continuing the polymerization reaction until the conversion rate of the vinyl aromatic monomer reaches 30 to 80% by weight.