JPH0841139A - Impact-resistant styrene resin composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain a styrene resin composition which gives a molding excellent in surface gloss, impact resistance, and appearance by producing a substance comprising specific dispersed rubber particles and given amounts of a styrene polymer ingredient, a diene polymer ingredient, styrene oligomers, and residual volatiles. CONSTITUTION:The composition comprises dispersed rubber particles having an average particle diameter of 0.2-1.0mum and an occlusion structure, 95-85wt.% styrene polymer ingredient, 5-15wt.% diene polymer ingredient in a rubbery polymer, up to 0.6wt.% styrene dimer and/or styrene trimer, and up to 700 ppm residual volatiles. It is preferably obtained by polymerizing a rubbery polymer having a styrene polymer chain content of 8-25wt.% with a styrene monomer in the presence of 250-600ppm polymerization initiator and degassing the resulting polymer to a total residual volatile content of 700ppm or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact-resistant styrene resin composition and a method for producing an impact-resistant styrene resin composition. More specifically, it has excellent surface gloss and impact resistance, and has a good appearance. And a shock-resistant styrene-based resin composition that can be suitably used in various fields including home electric appliances, OA equipment, and sheets. Regarding the method.

[0002]

2. Description of the Related Art Impact-resistant styrene resin compositions obtained by improving the impact resistance of general-purpose polystyrene have been used in various fields. However, the molded article of the impact resistant styrene resin composition has a problem that the surface gloss is not sufficient. In recent years, in order to expand the applications of impact-resistant styrene-based resin compositions, the development of impact-resistant styrene-based resin compositions that can be used as molded articles having good surface gloss has been actively pursued.

For example, Japanese Patent Application Laid-Open No. 4-264116 discloses that an impact-resistant styrene resin having excellent surface gloss is obtained. However, although the impact-resistant styrene-based resin produced by this method has excellent surface gloss, the impact resistance and the appearance of the molded product are not sufficient. In addition, JP-A-3
JP-A-162407 discloses that a styrene resin composition having excellent surface gloss and impact resistance is obtained.
However, the styrene resin composition obtained by this method also has a problem that the appearance of the molded product is not sufficient.

Therefore, at present, no impact-resistant styrenic resin composition excellent not only in surface gloss and impact resistance but also in appearance of a molded article is not provided.

Then, as a result of a study by the present inventors,
When a low molecular weight component that adheres to the surface of a molded article when the impact resistant styrene resin composition is molded and causes a poor appearance of the molded article is removed from the impact resistant styrene resin composition, the above conventional problems are solved. I got the knowledge that I can.

An object of the present invention is to solve the above conventional problems. Further, the present invention can be a molded product having excellent surface gloss and impact resistance and having a good appearance, and can be suitably used in various fields including home appliances, OA equipment, and sheets. An object of the present invention is to provide an impact resistant styrene resin composition and a method for producing an impact resistant styrene resin composition.

[0007]

The invention according to claim 1 for solving the above-mentioned problems has an average rubber particle diameter of from 0.2 to
1.0 μm, dispersed rubber particles having an occlusion structure, and styrene-based polymer component 95 to 85% by weight
And the diene polymer component 5 to 15 in the rubber-like polymer
%, At most 0.6% by weight of styrene-based dimers and / or styrene-based trimers, at most 700 pp
An impact-resistant styrenic resin composition having a residual volatile component of m, wherein the invention according to claim 2 is a rubbery polymer having 8 to 25% by weight of a styrenic polymer chain. And a styrene-based monomer, a polymerization initiator 250
Polymerization in the presence of ˜600 ppm, followed by degassing treatment so that the total amount of residual volatile components is at most 700 ppm. It is a manufacturing method.

<Impact-resistant styrene-based resin composition> The impact-resistant styrene-based resin composition according to the present invention comprises a specific dispersed rubber particle group, a specific amount of a styrene-based polymer component, and a rubber-like polymer. It contains a rubbery polymer containing a specific amount of a diene monomer component, a specific amount of a styrene-based dimer and / or a styrene-based trimer, and a specific amount of a residual volatile component.

(1) Dispersed Rubber Particle Group In the impact resistant styrene resin composition according to the present invention, the dispersed rubber particle group, that is, the rubber particle group dispersed in the matrix, has an average rubber particle size of 0.2 to 1 0.0 μm
And preferably 0.3 to 0.8 μm, and more preferably 0.3 to 0.6 μm. As a preferable range of the average rubber particle diameter in the rubber particle group, in some cases, 0.2 μm or 0.3 μm is set as a lower limit value, and 1.0 μm, 0.8 μm or 0.6 μm is set as an upper limit value. A range having a value of 0.2 μm or 0.3 μm as a lower limit and any rubber particle size described in Examples described in this specification as an upper limit. And the lower limit is any rubber particle size described in the examples described in this specification, 1.0 μm, 0.8 μm
And 0.6 μm can be used as the upper limit, and the smallest rubber particle size among the rubber particle sizes described in the examples described in this specification, and the next largest rubber particle size and The lower limit is any one of the three rubber particle sizes consisting of the next largest rubber particle size, and the largest rubber particle size among the rubber particle sizes described in the examples described in this specification,
It is possible to set a range having an upper limit value of any of three types of rubber particle diameters including the next smallest rubber particle diameter and the next smallest rubber particle diameter.

The average rubber particle size in the rubber particle group is 0.2
If it is less than μm, the impact resistance of the obtained resin composition is lowered and the object of the present invention cannot be achieved.
When the average rubber particle size exceeds 1.0 μm, the gloss of the obtained resin composition is so low as to cause a practical problem. vice versa,
When the average rubber particle diameter of the rubber particle group is within the above range, the impact resistance of the resulting resin composition is improved, and the gloss is also good, in combination with the other conditions specified in the present invention.

The average rubber particle size can be calculated as follows.

That is, pellets of the impact-resistant styrene resin composition according to the present invention were treated with an aqueous 3 wt% osmium tetroxide solution, and the treated pellets were thinned with an ultramicrotome. An electron micrograph (magnification of 25,000) was obtained, and about 1,
The major diameter (D) of the rubber particles was measured for 000 rubber particles, and the average rubber particle diameter (D _s ) as the area average value was calculated by the following formula.

D _s = [Σn · D ³ ] / [Σn · D ² ] (unit: μm) This rubber particle group has an occlusion structure.

The occlusion structure can now be described as follows. That is, first, a sample pellet was treated with a 3 wt% osmium tetroxide aqueous solution, the treated pellet was sliced with an ultramicrotome, and the stained slice surface was observed with a transmission electron microscope (magnification 25, 000 times), substantially all the rubber particles in the observation visual field are composed of rubber particles having inclusion-one occlusion particles which are formed by surrounding a non-stained portion with a dyed portion. The number of rubber particles having one occlusion particle is Z ₁ , and the number of rubber particles having 2 to 5 inclusion one occlusion particles is Z.
₂ , when the number of rubber particles having 6 or more inclusion one occlusion particles is Z ₃ , (1) the number of rubber particles having the inclusion one occlusion particles at a ratio of 5 or less (Z
₁ + Z ₂ ) is 70 of the total number of rubber particles (Z ₁ + Z ₂ + Z ₃ ).
% Or more, (2) the number of rubber particles having only one inclusion occluded joan (Z ₁ ), the number of rubber particles having inclusion one occlusion particles of 5 or less (Z ₁ +
It can be specified by being 50% or more with respect to Z ₂ ).

The dyed portion is a double bond component. It is considered that this double bond component is derived from the diene-based monomer component in the rubber-like polymer and the diene-based monomer component in the graft polymer obtained by grafting the styrene-based monomer onto the rubber-like polymer. Specifically, when this impact-resistant styrene-based resin composition is produced by using polybutadiene and styrene-butadiene copolymer rubber as the rubber-like polymer, these butadiene components form a dyed portion. This dyed part is usually called the shell.

The inclusion one occlusion has a structure in which a non-stained portion is surrounded by a stained portion. As described above, the stained portion is called a shell and the non-stained portion is called a core.

Although the shape of the core in the inclusion occlusion varies, the shell exists so as to surround the outline of the core.

This core has a styrene-based homopolymer produced by polymerization of a styrene-based monomer, and a styrene-based graft polymer grafted on a rubber-like polymer. Specifically, when the impact resistant styrene resin composition is produced using polybutadiene and styrene-butadiene copolymer rubber as a rubbery polymer and styrene as a monomer, the core is polymerized. It contains the polystyrene component produced in (3) and the polystyrene component in the styrene-butadiene copolymer rubber, and the graft polystyrene grafted on the styrene-butadiene copolymer rubber.

(2) Styrene-based polymer component This styrene-based polymer component is a styrene originally present in the matrix of the impact-resistant styrene-based resin composition according to the present invention and the rubber-like polymer in the rubber particles. A block polymer chain portion of the styrene-based monomer and a graft polymerized chain portion of the styrene-based monomer which is grafted to the rubber-like polymer when the impact resistant styrene-based resin composition is produced are formed.

The styrenic polymer component forming the matrix, the block polymer chain portion and the graft polymer chain portion is formed from a styrenic monomer. Examples of the styrene-based monomer include styrene, α-methylstyrene, vinyltoluene, vinylethylbenzene, vinylxylene, pt-butylstyrene and α-methyl-p-.
Methyl styrene etc. can be mentioned. These styrene-based monomers may be used alone or in combination of two or more. However, the preferred styrenic monomer is styrene.

The styrene polymer component may be a copolymer of the styrene monomer and a monomer copolymerizable therewith.

Examples of the monomer copolymerizable with the styrene monomer include aromatic monovinyl compounds such as vinylnaphthalene and bromostyrene, acrylonitrile, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, maleic anhydride, and phenylmaleimide. And so on. These monomers copolymerizable with the styrene-based monomer may be used alone or in combination of two or more. The content of the monomer copolymerizable with the styrene-based monomer in the styrene-based polymer component is usually 50% by weight or less, preferably 40% by weight or less.

The content of the styrenic polymer component in the impact-resistant styrenic resin composition according to the present invention is 95 to 85% by weight, preferably 94 to 86% by weight, based on the total of the rubber particle group and the matrix. %, More preferably 93
Is about 87% by weight. In some cases, the preferable range of the styrenic polymer component is 95% by weight, 94% by weight, or 93% by weight as an upper limit, and 85% by weight,
It is possible to set a range having a lower limit value of either 6% by weight or 87% by weight.

When the content of the styrene-based polymer component is within the above range, the impact resistance and gloss of the impact-resistant styrene-based resin composition are further improved, and the fluidity is good, so that the moldability is excellent. . 95% by weight of styrene polymer component
If it exceeds, the impact resistance is lowered and the object of the present invention cannot be achieved, and if it is less than 85% by weight, gloss and fluidity are lowered and the object of the present invention cannot be achieved.

(3) Diene Polymer Component The diene polymer component in the impact resistant styrene resin composition according to the present invention forms a diene polymer chain in the rubber-like polymer. Examples of this rubber-like polymer include a block copolymer rubber of a styrene-based monomer and a diene-based monomer, and a homopolymer rubber of a diene-based monomer.

Examples of the styrene-based monomer include the same compounds as exemplified in the above-mentioned section "(2) Styrene-based polymer component". Examples of the diene-based monomer include butadiene, isoprene and neoprene.

In the present invention, one kind of the rubbery polymer may be used alone, or two or more kinds thereof may be used in combination. However, the rubbery polymer preferable in the present invention is a two-component system of styrene-butadiene block copolymer rubber and polybutadiene rubber.

A preferred styrene-butadiene block copolymer rubber has a styrene content of 20 to 45% by weight, preferably 22 to 40% by weight, and a molecular weight distribution of 1.5 or less (in other words, at most 1.5). , Preferably 1.2
Below (in other words, at most 1.2), the solution viscosity is 8 to 50 cps, preferably 10 to 46 cps. When the styrene content in the styrene-butadiene block copolymer rubber is within the above range, the gloss of the impact-resistant styrene resin composition is further improved and the impact strength is further improved. Further, when the molecular weight distribution is within the above range, the gloss is further improved. When the solution viscosity is within the above range, the impact strength and gloss of the impact resistant styrene resin composition according to the present invention are further improved.

Such a styrene-butadiene block copolymer rubber can be produced by various methods, but the microstructure may be a taper type having a random component, or substantially. It may be a complete type having no random component. For example, JP-A-50-1
As described in Japanese Patent Publication No. 57493 and Japanese Patent Publication No. 54-19031, styrene and 1.3 are added in the presence of an organolithium catalyst in an inert hydrocarbon solvent such as hexane, heptane, and benzene. A styrene-butadiene block copolymer rubber can be produced according to a method of polymerizing with butadiene.

The preferred polybutadiene rubber has a solution viscosity of 30 to 220 cps, preferably 35 to 200 cps.
ps. When the solution viscosity of the polybutadiene rubber is within the above range, the impact strength of the impact resistant styrene resin composition according to the present invention can be further improved and the gloss is also improved.

The content of the diene polymer component in the impact resistant styrene resin composition is 5 to 15% by weight, preferably 6 to 14% by weight, more preferably 7 to 13% by weight. When the rubber-like polymer is a two-component system of styrene-butadiene block copolymer rubber and polybutadiene, the content of butadiene polymer chain and polybutadiene in the diene polymer component, that is, styrene-butadiene copolymer rubber is The content of the polybutadiene component in the impact-resistant styrene resin composition is 5 to 15% by weight, preferably 6 to 14% by weight, and more preferably 7 to 13% by weight.

When the amount of the diene polymer component is less than 5% by weight, the impact resistance of the impact resistant styrene resin composition is lowered and the object of the present invention cannot be achieved.
If the weight is exceeded, the gloss and fluidity will be reduced and the object of the present invention will not be achieved.

(4) Styrene-based dimer and styrene-based trimer The impact-resistant styrene-based resin composition of the present invention contains either or both of a styrene-based dimer and a styrene-based trimer. To do.

Examples of the styrene-based monomer that contributes to the formation of the styrene-based dimer and the styrene-based trimer include the same compounds as exemplified in the above-mentioned "(2) Styrene-based polymer component". it can.

The styrene-based dimer or styrene-based trimer is a styrene dimer or a styrene trimer, a dimer of styrene and another monomer copolymerizable with styrene, or styrene. And a trimer of other monomers copolymerizable with styrene, or a dimer of other monomers copolymerizable with styrene, or other monomers copolymerizable with styrene. A trimer etc. can be mentioned.

In the present invention, the styrene-based dimer may be only one of the above-mentioned various styrene-based dimers, or may be a plurality of the above-mentioned various styrene-based dimers. good. Similarly, the styrene-based trimer may be only one of the above-mentioned various styrene-based trimers, or may be a plurality of the above-mentioned various styrene-based trimers. Nevertheless, the preferred styrenic dimer is a styrene dimer and the preferred styrenic trimer is a styrene trimer.

In the present invention, the styrene type dimer and / or the styrene type trimer further contributes to the appearance of the impact resistant styrene type resin composition. In order to achieve the object of the present invention, the content of the styrene-based dimer and / or the styrene-based trimer in the impact-resistant styrene-based resin composition is at most 0.6% by weight, preferably many. Both 0.
It is 5% by weight, more preferably at most 0.4% by weight. If the content of the styrene-based dimer and / or the styrene-based trimer exceeds 0.6% by weight, the impact-resistant styrene-based resin composition may have a poor appearance and the object of the present invention may be achieved. Can not.

The preferred range of the content of the styrene-based dimer and / or the styrene-based trimer is
In some cases, 0.6% by weight, 0.5% by weight and 0.
It is possible to employ a range in which any one of 4% by weight is set as an upper limit value and any one of the oligomer amounts shown in Examples described in the present specification is set as a lower limit value. It is possible to adopt a range in which the upper limit value and the lower limit value are any values of the oligomer amount shown in the examples.

The styrenic dimer and / or the styrenic 3 in the impact-resistant styrenic resin composition according to the present invention.
The content of the monomer can be quantified as follows.

That is, 2 g of a high-impact styrene resin composition as a sample is dissolved in 80 ml of methylene chloride. The solution obtained is reprecipitated in 160 ml of methanol. After filtering the liquid containing the precipitate, the filtrate is concentrated to about 1 ml, and chloroform is added thereto to make a fixed volume of 20 ml. A constant volume chloroform solution is measured by an absolute calibration curve method using a gas chromatograph. Standards for styrene dimers are dibenzyl and styrene 3
The standard substance for the mer is 1,3,5-triphenylbenzene.

(5) Residual Volatile Component In the present invention, the content of the residual volatile component which is acceptable in the impact resistant styrene resin composition and achieves the object of the present invention is at most 700 ppm, preferably ,
It is at most 600 ppm, more preferably at most 500 ppm. The residual volatile content is 700p
When it exceeds pm, the appearance of the impact resistant styrene resin composition becomes poor, bleeding out occurs, and other practical problems occur.

There are no particular restrictions on the type of component that forms this residual volatile content, but in the usual case, the styrene-based monomer used in the production of this impact-resistant styrene-based resin composition is used. Alternatively, it is a monomer, a solvent, or the like that is copolymerizable with the styrene-based monomer.

Examples of the monomer copolymerizable with the styrene-based monomer include the same compounds as exemplified in the section "(2) Styrene-based polymer component". Specific examples of the solvent and the like will be described later. Will be clarified by the explanation of.

The residual volatile content in the impact resistant styrene resin composition according to the present invention can be quantified as follows. That is, 1 g of a sample which is a high impact styrene resin composition is dissolved in 20 ml of carbon disulfide. The solution is measured with a gas chromatograph by the internal standard method using cyclopentanol as an internal standard substance.

(6) Uses of Impact-Resistant Styrenic Resin Composition The impact-resistant styrene-based resin composition can be applied in various fields in various fields depending on its purpose. In particular, in the field of home appliances such as cabinets and front panels for TVs and radios, linings and dividers for refrigerators, panel boards for reel washing machines, lighting equipment, calculators, typewriters, copiers, etc. OA equipment field,
It can be suitably used in various fields such as a sheet field, a packaging / container field, furniture and building materials.

<Method for Producing Impact-Resistant Styrenic Resin Composition> In order to produce the impact-resistant styrene-based resin composition of the present invention, a rubber-like polymer having a specific amount of styrene-based polymer chains and a styrene-based polymer are used. The monomer and the monomer are polymerized in the presence of a polymerization initiator, and then deaerated so that the total amount of residual volatile components becomes a predetermined value.

(1) Components Used The rubber-like polymer is a rubber having a styrene-based polymer chain, and is the same as the rubber-like polymer described in the section of "(3) Diene-based polymer component". Can be used. The preferred rubbery polymer is a two component system of styrene-butadiene block copolymer rubber and polybutadiene rubber. The styrene-butadiene block copolymer rubber and polybutadiene are the same as those described in the above section "(3) Diene polymer component".

In the present invention, when the impact resistant styrene resin composition is produced, the styrene polymer chain in the rubber-like polymer is 8 to 25% by weight, preferably 10 to 2%.
It is necessary to select the type and amount of the rubber-like polymer so as to be 2% by weight, more preferably 12 to 20% by weight. For example, when using a copolymer rubber of a styrene-based monomer and a diene-based monomer, select a copolymer rubber having a ratio of the styrene-based polymer chain portion within the above range, and block copolymer of the styrene-based monomer and the diene-based monomer. When selecting two components of a polymer rubber and a homopolymer rubber of a diene monomer, the type of the block copolymer rubber and the block copolymer weight should be adjusted so that the ratio of the styrene polymer chain portion is within the above range. It is desirable to determine the compounding ratio of the combined rubber and the homopolymer rubber. In particular, when a two-component system of styrene-butadiene block copolymer rubber and polybutadiene rubber is adopted as a preferable rubber-like polymer, the content of styrene block in the styrene-butadiene block copolymer rubber and the styrene-butadiene block The blending ratio of the copolymer rubber and the polybutadiene rubber is adjusted so that the styrene polymer chain is within the above range.

When the styrenic polymer chain in the rubber-like polymer is within the above range, the rubber particles in the rubber particle group are not enlarged and are not made fine, and the object of the present invention can be achieved well. it can. On the other hand, if the styrene-based polymer chain is less than 8% by weight, the rubber particles are enlarged, and if it exceeds 25% by weight, the rubber particles are too fine and the object of the present invention cannot be achieved.

Examples of the styrene-based monomer include the same compounds as exemplified in the above-mentioned section "(2) Styrene-based polymer component". In the method of the present invention, a monomer copolymerizable with the styrene-based monomer can be used together with the styrene-based monomer as long as the object of the present invention is not impaired. As the monomer copolymerizable with the styrene-based monomer,
The same compounds as those exemplified in the section "(2) Styrene-based polymer component" can be mentioned.

The amount of the styrene-based monomer used is such that the content of the styrene-based polymer component in the resulting impact-resistant styrene-based resin composition is 95 to 85% by weight based on the total weight of the rubber particle group and the matrix. %, Preferably 94-86
%, More preferably 93-87% by weight, and in some cases 95%, 94%, and 93% by weight as the upper limit, and 85% by weight, 86% by weight, and 8% by weight.
Set the lower limit to either 7% by weight,
It is appropriately determined in consideration of the styrene polymer chain content in the rubber-like polymer.

Examples of the polymerization initiator include 1,1-bis (t-butylperoxy) cyclohexane and 1,1-
Peroxyketals such as bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, dicumyl peroxide, di-t-butyl peroxide, 2,5
-Dialkyl peroxides such as dimethyl-2,5-di (t-butylperoxy) hexane, benzoyl peroxide, diaryl peroxides such as m-toluyl peroxide, peroxycarbonates such as dimyristylperoxydicarbonate, t-butylperoxyisopropyl Examples thereof include peroxyesters such as carbonate, ketone peroxides such as cyclohexanone peroxide, and organic peroxides such as hydroperoxides such as p-menthane hydroperoxide. In the method of the present invention, an azo polymerization initiator such as azobisisobutyronitrile may be used in addition to the organic peroxide.

However, the above-mentioned organic peroxide can be mentioned as a preferable polymerization initiator, and peroxyketals are preferable among them.

In the method of the present invention, it is important to adjust the amount of the polymerization initiator used to 250 to 600 ppm, preferably 300 to 550 ppm, and more preferably 350 to 500 ppm. When the amount of the polymerization initiator used is less than 250 ppm, the total amount of styrene-based dimer and / or styrene trimer increases,
As a result, the impact-resistant styrene-based resin composition has a disadvantage of poor appearance, and the object of the present invention cannot be achieved. If the amount of the polymerization initiator used exceeds 600 ppm, a large amount of heat of polymerization reaction is generated, and the polymerization operation including the slow heating operation becomes complicated and difficult, which is not industrial.

A solvent can be used in the polymerization reaction in the method of the present invention. If you use a solvent,
It is preferable because the heat of polymerization can be efficiently removed and the rubber particles can be efficiently dispersed in the polymerization system. However, the use of a solvent is not an essential condition in the present invention, and bulk polymerization can be performed without using a solvent.

Examples of the solvent used include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mixtures of two or more of these.
In addition, as the solvent, other solvents can be used as long as they do not deviate from the object of the present invention, and specific examples thereof include aliphatic hydrocarbons and ketones such as dialkyl ketones. These solvents are preferably used in combination with the aromatic hydrocarbon.

The appropriate amount of the solvent used is at most 25% by weight based on the whole polymerization system. 25% by weight of solvent used
If it exceeds, the polymerization rate tends to be remarkably reduced, and the impact strength of the resulting impact resistant styrene resin composition tends to be reduced. Further, the solvent recovery operation becomes complicated, and the size and complexity of the apparatus are forced.

The solvent may be added to the polymerization system before the initiation of the polymerization, or may be added after the polymerization conversion rate increases and the polymerization system has a relatively high viscosity after the initiation of the polymerization.
From the viewpoint of uniformity of quality and control of polymerization temperature, 5 to 15% by weight based on the entire polymerization system is added to the polymerization system before the initiation of the polymerization, and the residual amount of the remaining amount after the viscosity of the polymerization system increases after the initiation of the polymerization It is preferred to add a solvent to the polymerization system.

In the method of the present invention, it is also preferable that a chain transfer agent is allowed to coexist during the polymerization in order to adjust the molecular weight of the polymer obtained when the styrene monomer is polymerized.

Examples of the chain transfer agent include α-methylstyrene dimer, n-dodecyl mercaptan, t
Examples thereof include mercaptans such as -dodecyl mercaptan, 1-phenylbutene-2-fluorene, dipentene, and chloroform, terpenes, and halogen compounds.

In the method of the present invention, in addition to the components described above, various additives can be optionally used within the range not impairing the object of the present invention.

As the additive, for example, stearic acid,
Lubricants such as behenic acid, zinc stearate, calcium stearate, magnesium stearate, ethylenebis stearamide, organic polysiloxane, mineral oil, or 2,6-di-t-butyl-4-methylphenol, stearyl-β- (3,5-di-t-butyl-
4-Hydroxyphenyl) propionate, hindered phenols such as triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate and tri (2,4-di-t-butyl). Phenyl), 4,4'-butylidene bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite and other phosphorus-based antioxidants, other UV absorbers,
Examples thereof include flame retardants, antistatic agents, release agents, plasticizers, dyes, pigments and various fillers. If desired, other polymers such as polystyrene for general use and polyphenylene ether may be added to the polymerization system.

(2) Polymerization Operation In the method according to the present invention, any known continuous bulk polymerization method, continuous solution polymerization method or the like may be adopted as long as the impact resistant styrene resin composition according to the present invention can be obtained. it can. For example, a method of preliminarily polymerizing in one or more tank type reactors, phase inversion in a multistage blade plug flow type reactor having a length / diameter (L / D) ratio of 3 or more, and further proceeding the polymerization, It is also possible to adopt a method of using a tubular reactor having a static mixer inside instead of the multi-stage blade plug flow reactor.

In the method according to the present invention, first, the rubber-like polymer and the styrenic monomer are mixed. in this case,
As a rule, the rubbery polymer dissolves in the liquid styrene monomer. Furthermore, a polymerization initiator, a chain transfer agent, an additive, and a solvent, if necessary, are added, the reaction temperature is maintained at 20 to 200 ° C. according to the decomposition temperature of the polymerization initiator, and the inside of the system is stirred to carry out the polymerization. It is good to proceed. Polymerization was allowed to proceed until the amount of unreacted styrenic monomer reached 30% by weight or less, and then the unreacted styrenic monomer was designed by a known method, for example, removal under reduced pressure under heating or removal of volatile matter. It is better to remove it with an extruder or the like.
Furthermore, it is preferable to subject the resulting composition to deaeration so that the total amount of residual volatile components in the composition is at most 700 ppm.

The preferable polymerization operation in the present invention will be described in more detail.

The impact-resistant styrenic resin composition according to the present invention is preferably subjected to a polymerization operation consisting of polymerization in the first polymerization zone and polymerization in the second polymerization zone.

In the first polymerization zone, the rubbery polymer is dissolved in the styrenic monomer. At this time, the styrene-based polymer component and the diene-based component in the impact-resistant styrene-based resin composition to be produced should be adjusted so that the content of the styrene-based polymer chain in the rubber-like polymer is within the above-mentioned predetermined range. The amounts of the rubber-like polymer and the styrenic monomer and other monomers to be added as necessary are determined in consideration of the polymer component within a predetermined range.

The styrene-based monomer solution in which the rubber-like polymer component is dissolved is initially polymerized in the first polymerization zone, preferably to 10 to 30% conversion just before the phase transition. When the conversion rate is within the above range, the heat removal load in the second polymerization zone that causes the next phase transition does not become large, the temperature control becomes easy, and the stirring failure due to the viscosity increase does not occur. It also facilitates control of the molecular weight distribution.

As the reactor used in the first polymerization zone for this initial polymerization, a complete mixing tank type is preferable, but a static type reactor whose recycling efficiency is improved by recycling can also be adopted.

As the polymerization temperature in the first polymerization zone, when an organic peroxide is used for the polymerization, a temperature within the range of 20 to 200 ° C. can be adopted depending on the decomposition temperature, and the thermal initiation polymerization can be carried out. In this case, a temperature within the range of 50 to 200 ° C can be adopted.

In the first polymerization zone, a chain transfer agent, a solvent and various additives can be used if necessary. When the chain transfer agent is used for the initial polymerization, it becomes possible to cause a decrease in the molecular weight and an increase in the particle size of the rubber particles at the same time depending on the amount added, and an organic peroxide was used. In this case, on the contrary, the particle size of the rubber particles can be narrowed. Therefore, the average rubber particle size of the rubber particles can be adjusted at the stage of this initial polymerization.

The number of polymerization vessels used in the first polymerization zone may be plural, such as two and three, in view of the scale of the apparatus. That is, multistage polymerization may be carried out in this first polymerization zone.

The polymerization liquid prepolymerized in the first polymerization zone is transferred to the second polymerization zone. In this second polymerization zone, a phase transition is carried out and rubber particles are formed so as to have a predetermined average rubber particle diameter. In this second polymerization zone, the conversion is 30-95.
Stabilize the rubber particles by advancing the polymerization until the content becomes%. When the conversion is within the above range, the rubber particles are stably formed and the viscosity of the polymerization system does not increase, so that the rubber particle size distribution does not expand.

In order to control the average rubber particle diameter of the rubber particles to a predetermined value, it is preferable to adjust the average shear rate in the second polymerization zone. This average shear rate is an index showing the strength of the shearing force in the field where the phase transition occurs in the reactor, and the average rubber particle diameter of the rubber particles can be adjusted by this strength. However, since the phase transition phenomenon varies depending on the type of reactor, the appropriate range of the average shear rate is appropriately determined for each reactor.

As the polymerization vessel used in the first polymerization zone,
When a plug flow type such as a tower type or a tube type is adopted, the particle size distribution of rubber particles dispersed in the matrix can be narrowed. For example, as a tower reactor,
A reactor having a tower height / tower diameter (L / D) ratio of 3 or more, which has a multistage stirring blade and a heat transfer tube for heat removal between the stages, for example, described in JP-A No. 32-1544. A known reactor or the like can be used.

As the tubular reactor, a reactor having an L / D of 5 or more, which has a heat transfer tube for the purpose of heat removal and mixing therein, can be used.

When the above plug flow type reactor is used, a chain transfer agent is introduced at a predetermined amount, for example, 50 to 50 at the inlet.
By adding 1,500 ppm, the molecular weight of the matrix molecule can be controlled without changing the particle diameter of the rubber particles.

When the predetermined addition rate is achieved in the second polymerization zone, the polymerization reaction product obtained in the second polymerization zone is subjected to a degassing operation.

The deaeration operation can be carried out by using a generally known flash drum, a twin-screw deaerator, a thin film evaporator, an extruder or the like. This degassing operation has a residual volatile content of at most 70
The temperature, the degree of vacuum (also referred to as the degree of reduced pressure), etc. are appropriately determined so as to be 0 ppm so that the optimum conditions are obtained.

As described above, the impact resistant styrene resin composition according to the present invention can be obtained.

[0081]

EXAMPLES Examples and comparative examples of the impact-resistant styrene resin composition and the method for producing the impact-resistant styrene resin composition of the present invention will be described below. However, the present invention is not limited to these examples and comparative examples. It is not limited to the examples.

(Examples 1 to 12 and Comparative Examples 1 to 9) Styrene and styrene-butadiene block copolymer rubber (hereinafter abbreviated as SB) (manufactured by Bayer, trade name; BL6533 [registered trademark]) were added. Polybutadiene (hereinafter abbreviated as PB) (manufactured by Asahi Chemical Industry Co., Ltd.,
Trade name: NF35AS [registered trademark]) and 1,1-di-t-butylperoxy-3,3,5-as a polymerization initiator
Trimethylcyclohexane and n-dodecyl mercaptan as a chain transfer agent were dissolved and supplied to a 19-liter tank-type first polymerization vessel at a flow rate of 32 liters / hour.

However, the ratio of SB to PB (SB / PB
(Weight ratio) is 4/6, SB and PB are supplied so that the total of SB and PB is 12.5% by weight with respect to the total amount of the raw materials supplied to the first polymerization vessel, and the polymerization initiator is mixed. The amount is 0.04% by weight (400 pp
m), the blending amount of the chain transfer agent was adjusted to be 0.02% by weight based on the total amount of the raw materials.

In the first polymerization vessel, the conversion of styrene was 10% under the conditions of polymerization temperature of 111 ° C. and stirring speed of 120 rpm.
Polymerization was carried out until. Then, this partial polymerization liquid is added to 23
The mixture was transferred to a second liter polymerization vessel and polymerized at a polymerization temperature of 116 ° C. and a stirring rate of 200 rpm until the conversion rate of styrene was 20%. Further, this partial polymerization liquid is continuously transferred to the third polymerization reactor, the fourth polymerization reactor and the fifth polymerization reactor,
In the polymerization vessel, the reaction temperature is 140 ° C and the stirring speed is 90 rpm.
Polymerization was carried out until the conversion of styrene reached 50%. In the fourth polymerization vessel, the reaction temperature was 145 ° C and the stirring speed was 2
Polymerization was performed at 0 rpm until the conversion of styrene reached 65%. In the fifth polymerization reactor, the reaction temperature was set to 162 ° C., the stirring speed was set to 5 rpm, and the polymerization was performed until the conversion of styrene reached 85%.

The polymerization reaction liquid obtained in the fifth polymerization reactor was charged with the first flash drum (temperature: 200 ° C., pressure: 0.053 M).
Pa) and a second flash drum (temperature 240 ° C., pressure 0.67 KPa) were performed to remove volatile components. The solids removed from the second flash drum were pelletized with an extruder.

The above-mentioned polymerization conditions and operating conditions in Examples 1 to 12 and Comparative Examples 1 to 9 are shown in Tables 1 and 2.

In Example 9, a polymerization initiator (di-t-butyl peroxide) was further added to the third polymerization vessel.

In Example 11, as the polybutadiene rubber, BR15HB [registered trademark] manufactured by Ube Industries, Ltd. was used instead of NF35AS [registered trademark] manufactured by Asahi Kasei.

In Example 12, a styrene solution in which a styrene-butadiene block copolymer rubber and a polybutadiene rubber were dissolved was used, to which 10% by weight of ethylbenzene was added.

The obtained pellets were analyzed and evaluated as follows.

-Analysis- <Occlusion Structure> The occlusion structure was analyzed by the method described above.

<Average Rubber Particle Diameter> The average rubber particle diameter was measured by the method described above.

<Total amount of styrene dimer and trimer> 2 mg of a sample is dissolved in 80 ml of methylene chloride. The solution is reprecipitated in 160 ml of methanol. After filtering this, the filtrate is concentrated to about 1 ml, and chloroform is added thereto to adjust the volume to 20 ml.

This solution was subjected to gas chromatography (manufactured by Shimadzu Corporation, GC-14A; column = PEG20).
M, 25%, 3 mm diameter × 3 m) was measured by an internal standard method using cyclopentanol as an internal standard substance.

<Total Amount of Residual Volatile Components> 1 g of the sample is dissolved in 20 ml of carbon disulfide. Gas chromatograph device (manufactured by Shimadzu Corporation, gas chromatography GC-
14A, column: PEG20M 25%, 3 mmΦ x 1
In m), cyclopentanol is used as an internal standard substance and the internal standard method is used for measurement.

<Polybutadiene Component Content> Calculated from the charged amounts of SB and PB, the usage ratio, the butadiene content in SB, and the final conversion rate of styrene.

<Polystyrene Component Content> It was calculated by subtracting the polybutadiene component content from the obtained composition (100%).

-Evaluation- <Melt Index (MI)> JIS-K-7
It measured according to 210.

<Surface gloss> Length 270 mm, width 70 m
JIS-K
It measured based on -7105.

<Izod impact strength> JIS-K-71
It measured based on 10 (notch, 23 degreeC).

<Impact strength of falling weight> Length 270 mm, width 70
mm, height 3 mm, injection-molded plate, at the center 125 mm from the gate position at its end,
A load of 3.76 kg, a speed of 3.5 m / sec, a hole diameter of the sample fixing part of 2 inches, and a temperature of 23 ° C. were used for the rheometrics automatic drop weight impact tester (RDT50 manufactured by Rheomerix Co., Ltd.
00) to determine the energy up to the point where the force first shows a sharp decrease in the curve of force and displacement,
This was defined as the falling weight impact strength.

<Appearance evaluation> Width 100 mm, length 420 m
m, using a mold having an internal space shape of 3 mm in thickness,
A sample colored with carbon black was injected by a short shot from both ends in the longitudinal direction of the mold by a two-point side gate (gate diameter was 3 mm), and was molded so that a weld was generated at the center. The length in the longitudinal direction of a glossy cloudy portion appearing around the weld in this injection molded product was measured and evaluated. The numerical value shown in the table is the length of the cloudy portion in the longitudinal direction.

[0103]

[Table 1]

Note: "Arrow" indicates that the value in the left column is the same. The underlined values are shown to be different from those in Example 1.

[0105]

[Table 2]

Note: "Arrow" indicates that the value in the left column is the same. The underlined values are shown to be different from those in Example 1.

[0107]

[Table 3]

[0108]

[Table 4]

A number with an underline indicates that the value is out of the range specified in the present invention or that the value is inferior to that in the examples.

[0110]

EFFECTS OF THE INVENTION According to the impact-resistant styrene resin composition of the present invention, a molded article having excellent surface gloss and impact resistance and having a good appearance can be obtained, and each physical property is improved in a well-balanced manner. An impact styrene resin composition can be provided.

This impact-resistant styrenic resin composition is used in the field of home appliances such as cabinets and front panels of televisions and radios, linings and partition boards of refrigerators, panel boards of reel washing machines, lighting equipment and the like. , Calculators, typewriters, copiers and other OA equipment fields,
It can be suitably used in various fields such as a sheet field, a packaging / container field, furniture and building materials.

According to the method for producing an impact-resistant styrene resin composition of the present invention, the impact-resistant styrene resin composition having excellent physical properties in a well-balanced manner can be efficiently produced by a simple operation. It is possible to provide a method for producing an impact-resistant styrene resin composition that can be used.

Claims (2)

[Claims] 1. A group of dispersed rubber particles having an average rubber particle diameter of 0.2 to 1.0 μm and having an occlusion structure, 95 to 85% by weight of a styrene-based polymer component, and a diene-based weight of a rubber-like polymer. Impact resistance, characterized by having 5 to 15% by weight of coalescing components, at most 0.6% by weight of styrene-based dimers and / or styrene-based trimers, and at most 700 ppm of residual volatile components. Styrenic resin composition. 2. A rubber-like polymer having 8 to 25% by weight of a styrenic polymer chain and a styrenic monomer are polymerized in the presence of 250 to 600 ppm of a polymerization initiator, and thereafter,
The method for producing an impact-resistant styrene-based resin composition according to claim 1, wherein the deaeration treatment is performed so that the total amount of residual volatile components is at most 700 ppm.