JP2001098037A - Method for producing rubber modified styrenic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a rubber modified styrenic resin composition which excels in impact resistance and the external appearance, such as gloss, of a molded article prepared therefrom. SOLUTION: A process for producing a rubber modified styrenic resin composition comprising continuously introducing a feedstock solution having a styrenic monomer and a rubbery polymer as the major components into at least one reactor to simultaneously effect polymerization reaction and granulation of the rubber component, thereafter increasing the polymerization conversion in at least one reactor to obtain a reaction product, and removing unreacted monomer by volatilization from the reaction product, wherein the polymerization is effected in such a manner that the average number of graft reaction sites of the rubbery polymer to which a styrenic resin has been grafted in the reaction product at the outlet of the reactor in which the rubber component has been granulated comes to 1.0-2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a rubber-modified styrene resin composition. More specifically, the present invention relates to a method for producing a rubber-modified styrene resin composition having excellent impact strength and excellent appearance of a molded article such as gloss.

[0002]

2. Description of the Related Art Generally, rubber-modified styrenic resin compositions have characteristics such as excellent impact resistance and excellent appearance such as gloss, depending on the particle size and distribution of rubber particles. Therefore, in order to produce a rubber-modified styrenic resin composition having excellent impact resistance or improved appearance such as gloss, the particle size of the rubber particles dispersed in the resin composition is adjusted to an appropriate size. It is known to adjust or adjust the particle size distribution to an appropriate range. For example, Demilos
(Polym. Mater. Sci. Eng.,
79, 162 (1998)), the notched Izod impact strength of impact-resistant polystyrene (HIPS) has a maximum value at 3 μm when the particle size is one peak distribution,
It is described that HIPS having a two-peak distribution composed of small particles having a particle size of 0.2 μm and large particles having a particle size of 3 to 5 μm has higher impact strength.

[0003] Therefore, as a method of obtaining a rubber-modified styrenic resin composition which is excellent in impact resistance and excellent in appearance such as gloss, two types of rubber particles having a small particle diameter and a large particle diameter are used. A rubber-modified styrenic resin composition comprising particles (referred to as “two-peak distribution”) has been proposed. As a method for producing a rubber-modified styrenic resin composition having a two-peak distribution, a rubber-modified styrenic resin composition composed of rubber particles having a small particle diameter and a rubber-modified styrene resin composition composed of rubber particles having a large particle diameter have been proposed. A method of blending and melt-kneading the resin composition, or after polymerizing a rubber-modified styrenic resin composition having different particle size distributions in two reactors, mixing them in the next reactor and further polymerizing. How to proceed or 2
There is a method of polymerizing by mixing and using various types of rubber.

[0004] However, the former requires post-processing of the resin composition obtained after the polymerization reaction, and thus has a problem of inferior in cost and productivity, and the latter has a usual one-peak distribution. In addition to the rubber-modified styrene-based resin composition manufacturing equipment, an extra reactor for the rubber-modified styrene-based resin composition having different particle size distribution is required, and when two kinds of rubber are mixed and polymerized. In addition, an extra rubber dissolving tank is required in addition to the usual apparatus for producing a rubber-modified styrene resin composition having a single peak distribution, and thus there are problems in equipment and cost.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems, and is intended to provide a rubber-modified styrene resin composition having excellent impact strength and excellent appearance of a molded article such as gloss. Production of a rubber-modified styrenic resin composition that can be produced efficiently by adjusting the granulation of the rubber component in the polymerization step without changing the equipment for producing the rubber-modified styrenic resin composition having a single peak distribution It provides a method.

[0006]

According to the present invention, a raw material solution mainly composed of a styrenic monomer and a rubber-like polymer is continuously charged into at least one reactor to simultaneously carry out the polymerization reaction and the rubber component. The rubber-modified styrenic resin composition is continuously formed by increasing the polymerization conversion in at least one reactor to obtain a reaction product, and devolatilizing unreacted monomers from the reaction product. In the method, the rubber component is polymerized so that the average graft reaction number of the rubbery polymer grafted with the styrene-based resin in the reaction product at the outlet of the reactor where the rubber component has become particles is 1.0 or more and 2.0 or less. The present invention relates to a method for producing a rubber-modified styrene resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The raw material used in the production method of the present invention comprises a raw material solution mainly composed of a styrene monomer and a rubber-like polymer. As the styrene monomer constituting the raw material solution, styrene is typically typical, for example, o-methylstyrene, m-styrene
-Nucleated alkyl-substituted styrenes such as -methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene and p-tert-butylstyrene; and α-alkyls such as α-methylstyrene and α-methyl-p-methylstyrene. Substituted styrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, 2-
Nuclear halogen-substituted styrenes such as methyl-1,4-chlorostyrene and 2,4-dibromostyrene may be mentioned, and these may be used alone or in a mixture of two or more. Also,
The method of mixing may be copolymerization or blending of multimers.

Further, a monomer capable of copolymerizing a part of the styrene monomer with the monomer, for example, (meth) acrylic acid such as acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, etc. It can be used in place of acid esters, furthermore, maleic anhydride, acrylonitrile and the like. Of these, styrene is preferred as the styrene monomer. The rubber-like polymer in the raw material solution has a glass transition temperature of 0 ° C. or lower, preferably −
20 ° C. or lower, for example, polybutadiene, butadiene-styrene copolymer, polyisoprene, butadiene-acrylonitrile copolymer, ethylene-propylene- (non-conjugated diene) copolymer, isobutylene-isoprene copolymer, styrene -Butadiene-styrene block copolymer, styrene-butadiene-styrene radial tere block copolymer, styrene-isoprene-styrene block copolymer, hydrogenated diene (block, random and homo) polymers such as SEBS, poly Acrylic rubber such as butyl acrylate, polyurethane rubber and the like can be mentioned. These rubbery polymers may be used alone or as a mixture of two or more.

Although the molecular weight and the degree of branching of the rubbery polymer are not particularly limited, the viscosity of a 5% by weight styrene solution at a temperature of 25 ° C. is 80 to 120 centipoise (cps). A range is preferred. Among these, polybutadiene, butadiene-styrene copolymer, ethylene-α-olefin (non-conjugated diene) copolymer, ethylene-propylene- (non-conjugated diene) copolymer, hydrogenated diene-based polymer, and acrylic rubber Preferably, more preferably, polybutadiene. And
The composition of the raw material solution mainly composed of the styrene-based monomer and the rubber-like polymer is usually 80-98.
The rubbery polymer is 2 to 20% by weight based on the weight of the polymer, and if necessary, a solvent such as an aromatic hydrocarbon composed of one or a mixture of two or more of toluene, xylene, and ethylbenzene is added to the content. For the purpose of lowering the viscosity, for example, it can be used in a range of up to 20% by weight. Among them, ethylbenzene can be generally used.

The raw material solution contains a small amount of a polymerization initiator such as 1,1-bis (t-butylperoxy) cyclohexane and 1,1-bis (t-butylperoxy).
Peroxyketals such as 3,3,5-trimethylcyclohexane, di-t-butyl peroxide, 2,5-
Dialkyl peroxides such as dimethyl-2,5- (t-butylperoxy) hexane; diacyl peroxides such as benzoyl peroxide and m-toluoyl peroxide; and peroxydienes such as dimyristyl peroxy dipercarbonate. Percarbonates, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as cyclohexanone peroxide, p-menthane hydroperoxide and the like. Hydroperoxides may be added for use. These may be used alone or in combination of two or more. It is preferable to use the polymerization initiator because it is effective not only for performing the polymerization reaction but also for controlling the average number of graft reaction points. These may be used alone or in combination of two or more. Further, a chain transfer agent may be used for the raw material solution. Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, terpinolene and the like. These are at least 2
You may mix and use more than seeds.

In the production method of the present invention, the raw material solution is continuously charged into at least one reactor, and the rubber component is formed into particles simultaneously with the polymerization reaction. The number of reactors used until the rubber component is made into particles may be one or more, as long as it can continuously supply the liquid to the next reactor for increasing the polymerization conversion. Preferably, the number of equivalent tanks in the complete mixing tank row model is 10 or less. As a reactor used until the rubber component is granulated, a complete mixing reactor is preferable, and a stirring blade mounted in the complete mixing reactor is preferably a helical ribbon, a double helical ribbon, a type such as an anchor. Wings. In the case of a helical ribbon type blade, a draft tube can be attached, so that vertical circulation in the reactor can be further enhanced, which is preferable. It is important to have a distribution in the effluent of the reactor to be made into particles in this way, in order to have an excellent balance of physical properties.

Next, after the rubber component is formed into particles, a reaction for increasing the polymerization conversion is performed in at least one reactor. Although the particle diameter slightly changes due to the reaction for increasing the polymerization conversion rate after the formation of the particles, the change does not occur so much as to change the shape of the particle size distribution when the particles are formed. Specific examples of the reactor used for the reaction for increasing the polymerization conversion rate include a plug flow type reactor in which a stirring chamber and a shell-and-tube type heat exchanger of a multi-tube type are alternately combined, and a vertically long vessel for cooling. Examples include a plug flow type reactor in which a pipe and a stirrer are combined, and a complete mixing tank. If there is no so-called dead space, a device without a stirrer can be used. It is not desirable to increase the number of reactors economically, and it is usually preferable to use 1 to 3 reactors. At the outlet of the final reactor, the polymerization conversion is 80-9.
The polymerization reaction is carried out until the content becomes 5% by weight, and the unreacted monomers are devolatilized to produce a rubber-modified styrene resin composition. Further, the polymerization temperature range in the production method of the present invention,
The test is performed at 100 to 200 ° C. (see “Assessment of High Impact Polystyrene (HIPS) Manufacturing Process (Reaction Engineering Research Group Research Report), pp. 8-12)”.

According to the study of the present inventors, the particle size distribution is controlled by controlling the number of graft reaction points of the styrene resin onto the rubbery copolymer when the particles are formed into particles, and the impact resistance and the molding resistance are improved. It has been found that a rubber-modified styrenic resin composition having excellent appearance can be obtained. That is, in the production method of the present invention, the average graft reaction number of the rubbery polymer grafted with the styrene-based resin in the reaction product at the outlet of the reactor where the rubber component has become particles is 1.0 or more and 2.0 or less. is necessary. The number of grafting reaction points indicates the number of branches of the styrene resin grafted on the main chain of the rubbery polymer, and thus the styrene resin is grafted as a branch on the rubbery polymer. Is, for example, Polym
er, Vol. 35, No26, p5693-569
8. 1994 and Polymer Collection Vol. 40, No10,
p629-635.1983. The average number of graft reaction points is an average value of the number of branches of the styrene-based resin grafted to one rubber-like polymer in the particles obtained by converting the rubber component into particles.

The particleization of the rubber component means that when a uniform raw material solution comprising a styrene monomer and a rubbery polymer is polymerized, the styrene monomer and its polymer are contained in the initial stage of polymerization. When the solution (resin phase) separates from the solution (rubber phase) containing the rubbery polymer and the styrene-based monomer, the rubber phase becomes a continuous phase and the resin phase becomes a dispersed phase. It is said that the resin phase becomes a continuous phase and the rubber phase becomes a dispersed phase, so-called phase inversion occurs, and the rubber component becomes particles. The average number of graft reaction points is calculated by Equation 1.

[0015]

(Equation 1)

Here, w (St) represents the weight fraction of the styrene resin monomer of the rubbery polymer grafted with the styrene resin, and w (Bd) represents the rubber grafted with the styrene resin. 2 shows the weight fraction of the monomer of the rubber-like polymer of the rubber-like polymer. The weight fraction can be determined by taking out a rubbery polymer grafted with a styrene-based resin from the reaction product at the outlet of the reactor that has been made into particles to be measured, and quantifying it by an infrared absorption spectrum. For example, when the monomer of the styrene resin is styrene and the monomer of the rubbery polymer is butadiene, first, polybutadiene to which polystyrene is grafted in the reaction product at the outlet of the reactor that has been formed into particles is taken out. In this case, in addition to the polybutadiene grafted with polystyrene, polystyrene and polybutadiene are mixed in the reaction product.
-Centrifuge with butanone to remove the insoluble portion.
The 2-butanone-soluble portion contains polystyrene.

Further, after the 2-butanone-insoluble part is centrifuged several times with toluene, the obtained insoluble part is dried to obtain polybutadiene grafted with polystyrene. The weight fraction of styrene and the weight fraction of butadiene are determined by quantifying the insoluble portion from the infrared absorption spectrum using an infrared spectrophotometer. At this time, in order to determine the fractions of styrene and butadiene, a calibration curve was prepared using a sample in which the ratio of the mixture of polystyrene and polybutadiene was varied from 0 to 100%, and the weight fraction of styrene was determined. And the weight fraction of butadiene are determined. Next, Mn (PS) is the number average molecular weight of the styrene resin of the rubbery polymer grafted with the styrene resin, and Mn (PBd) is the number of the rubbery polymer of the rubbery polymer grafted with the styrene resin. The number average molecular weight is shown.

However, since it is practically difficult to measure the number average molecular weight of the styrene resin and the rubber polymer of the rubber polymer to which the styrene resin is grafted, the number of the graft reaction points of the present invention is determined. , The number average molecular weight of the styrene resin obtained from the reaction product at the outlet of the granulated reactor, assuming the same as the number average molecular weight of the styrene resin obtained from the reaction product at the reactor outlet at the particle size. Was used. The number average molecular weight of the rubbery polymer was defined as the number average molecular weight of the rubbery polymer used as a raw material. The number average molecular weight can be determined by, for example, measurement using GPC or the like.

For example, when the styrene resin monomer is styrene and the rubbery polymer monomer is butadiene, Mn (PS) is the number average molecular weight of polystyrene in the 2-butanone-soluble part, Mn (PBd) can be determined by measuring the number average molecular weight of the raw material polybutadiene by GPC.
As described above, in Equation 1 for calculating the average number of graft reaction points, the denominator represents the number of rubbery polymers of the rubbery polymer to which the styrene resin is grafted, and the molecule is styrene of the rubbery polymer to which the styrene resin is grafted. This means that the number of the styrene-based resins is represented, and as a result, Equation 1 represents the average of the number of the styrene-based resins grafted on one rubber-like polymer.

When the average number of graft reaction points when the particles are formed is 1.0 or more and 2.0 or less, the obtained rubber-modified styrenic resin composition is excellent in the molded article appearance such as impact strength and gloss. The reason for this is not clearly understood, but the following hypothesis is conceivable. It is considered that the rubber particles are repeatedly united and divided by the stirring in the reaction tank where the particles are formed. It is considered that the rubber particle diameter here is determined not only by the stirring speed but also by the viscosity of the rubber particles as the dispersed phase, the viscosity of the styrene resin as the continuous phase, and the surface force between the particles. Some styrene-based resins grafted to the rubbery polymer were precipitated in the rubberized polymerized particles, and styrene-based resins not grafted to the rubbery polymer were also incorporated into the particles. It is known that a spherical domain, a columnar domain or a plate domain called occlusion is formed.

As described above, the number of graft reaction points indicates the number of branches on which the styrene resin is grafted on the rubbery polymer. It is known that the difference in the viscosity in the rubber particles depends on the number of the branches. For example, Macrom
olecules, 28, 14, 5006, (199
In 5), two branches made of a styrene-based resin ("the number of graft reaction points 1" in the present invention) and two ("the number of graft reaction points 2" in the present invention) are two. It is reported that the viscosity of the rubber particles is high. Thus, the greater the number of branches, the more likely that the branches belong to adjacent styrenic resin domains throughout the rubber particle, and due to such physical bridging, the rubber particles It is expected that the viscosity inside will be much higher than the viscosity of the rubbery polymer alone.

That is, in the case of rubber particles composed of a graft copolymer having an average number of graft reaction points exceeding 2.0, since there are many graft copolymers having two or more graft reaction points (number of branches), the particle size of the particles is large. Due to the remarkable thickening, the particles are hardly split, and the coalescence between the particles is preferentially performed, so that the rubber particle diameter becomes very large,
As a result, it is considered that the obtained rubber-modified styrene resin composition does not give a satisfactory molded product appearance.
On the other hand, in the case of rubber particles composed of a graft copolymer having an average number of graft reaction points of less than 1.0, since the number of branches is small, the thickening effect due to physical crosslinking is very small, so that the viscosity of the rubber particles is small. And the particle size of the rubber particles was very small, and it is considered that the obtained rubber-modified styrene resin composition cannot obtain satisfactory impact strength.

If the average graft reaction number of the reaction product at the outlet of the reactor where the rubber component has become particles, which is a requirement of the present invention, is 1.0 or more and 2.0 or less, the viscosity within the rubber particles as the particle diameter becomes remarkable. It is anticipated that the particle size distribution will be a two-peak distribution due to the presence of a material having a large particle size that is difficult to split due to high particle size and a material having a small particle size due to low viscosity. You. As described above, by controlling the number of grafts of the styrene-based resin to the rubber-like copolymer at the time of granulation, the particle size distribution of the rubber-like polymer spontaneously becomes a two-peak distribution, and the impact strength and It is presumed that a rubber-modified styrenic resin composition excellent in the appearance of a molded article can be obtained.

In the method of the present invention, the average number of graft reaction points of the reactant at the outlet of the reactor which has been made into particles is 1.0 or more.
In order to reduce the value to 0 or less, the residence time, conversion, and temperature of the reactor until the particles are formed are adjusted, and the type of the initiator used, the concentration of the initiator, and the type of the rubber polymer ( Molecular weight) and the concentration used can be adjusted. The rubber-modified styrenic resin composition obtained by the production method of the present invention is obtained by dispersing a rubbery polymer in a matrix mainly composed of a styrenic resin in the form of particles. Is 3 to 1
5% by weight and 85 to 97% by weight of a styrene resin. Further, for the rubber-modified styrenic resin composition, various additives such as dyes and pigments, coloring inhibitors, antioxidants, light stabilizers, lubricants, lubricants, antistatic agents, fillers, release agents, etc. It can also be added. These additives may be added to the polymerization reaction solution, may be added to the polymerization reaction solution during the polymerization, during the polymerization, or may be added to the resin composition after the completion of the polymerization.

As specific examples, examples of a coloring inhibitor and an anti-aging agent include phenol derivatives such as hindered phenols, hindered bisphenols and hindered trisphenols, quinoline derivatives, p-phenylenediamine derivatives. Derivatives, hydroquinone derivatives, thiocarbamate derivatives, phosphite derivatives and the like. These may be used alone or in combination of two or more. Examples of the light stabilizer include salicylic acid ester derivatives, benzophenone derivatives, benzotriazole derivatives, benzoate derivatives, cyanoacrylate derivatives, hindered amine compounds, nickel complex salts, and the like. These may be used alone or as a mixture of two or more kinds, and may be used in an amount of 0.01 to 1 based on 100 parts by weight of the resin composition.
It can be used in the range of parts by weight.

Examples of the lubricant include organopolysiloxanes, aliphatic hydrocarbon waxes, ester waxes of higher fatty acids and higher alcohols, higher fatty acids such as bisamides, higher fatty acids such as stearic acid, lauric acid and behenic acid, and zinc stearate. And metal salts of higher fatty acids such as magnesium stearate and calcium stearate. These may be used alone or in combination of two or more, and may be used in an amount of 0.0 to 100 parts by weight of the resin composition.
It can be used in the range of 1 to 1 part by weight. And
Examples of the lubricant include plasticizers such as dioctyl phthalate, dibenzyl phthalate, chlorinated aliphatic esters, and chlorinated paraffin, and mineral oil. These may be used alone or as a mixture of two or more, and may be used in the range of 0.01 to 5 parts by weight based on 100 parts by weight of the resin composition.

The rubber-modified styrenic resin composition obtained by the production method of the present invention is in the form of pellets, granules or beads, and is used as a resin composition which is dry-blended with general-purpose polystyrene or melt-kneaded. In addition, the resin composition can be prepared by blending with a polymer other than general-purpose polystyrene, and can be suitably used for molding materials such as light electric appliances and sundries.

[0028]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 Styrene monomer 75.8% by weight, ethylbenzene 13.
9% by weight of polybutadiene A (a 5% by weight styrene solution has a viscosity of 95 cps at a temperature of 25 ° C., and the microstructure is 1,2-vinyl structure 18% by weight, 1,4-cis structure 33% by weight. , 49% by weight of 1,4-trans structure)
To 49 parts by weight of a solution in which 8.6% by weight was dissolved, 0.049 parts by weight of t-butyl peroxybenzoate was mixed as an initiator. This raw material liquid was continuously supplied at a rate of 7.75 L / hour to a first reactor of a complete mixed phase equipped with a double helical blade stirrer equipped with a draft tube having an internal volume of 25 L. The temperature of the first reactor was 106.5 ° C., and the rotation speed of the stirring blade was 50 rpm. The residence time in the first reactor was 3.2 hours.

The weight concentration of the solid content of the polymerization reaction product at the outlet of the first reactor was 29.0% by weight. Further, when the syrup at the outlet of the first reactor was confirmed by a phase contrast microscope (× 400), it was found that the rubber component had become particles (“Polymer Papers” Vol. 40, No. 10, p631.1983 F).
ig, 3. Structure similar to C). The polymerization reactants continuously taken out of the first reactor were placed in series.
Two 5 L plug flow reactors (second reactor and third reactor)
Reactor). With respect to the polymerization reactant supply rate (L / hr) to the plug flow type second reactor,
Α-methylstyrene dimer as a chain transfer agent in an amount of 0.0
7% by weight, 0.05% by weight of zinc stearate as a lubricant
Was added continuously. The polymerization was carried out by adjusting the temperatures of these two plug flow reactors as described in Table 1. The solids weight concentration at the outlet of the third reactor was 84.0% by weight.

The polymerization liquid obtained from the third reactor was introduced into a devolatilizer to remove unreacted styrene monomer and ethylbenzene as a solvent. After completion of the devolatilization operation, the resin composition was extruded into a strand and cooled to obtain a pellet-shaped rubber-modified styrene resin composition. Table 1 shows the rubber components used in the polymerization, the concentration of the initiator, the temperature in each reactor, the solid weight concentration at the outlet of each reactor, and the results of evaluating the physical properties of the obtained rubber-modified styrene resin composition. The physical properties of the obtained rubber-modified styrenic resin composition were evaluated as shown below.

(1) Charpy impact (kJ /
m ² ) The pellets obtained in the examples were IS90B (manufactured by Toshiba)
Was used and injection molding was performed under the conditions of a resin temperature of 200 ° C. and a mold temperature of 40 ° C. to prepare a test piece of 80 mm × 10 mm × 4 mm. A predetermined notch is made in the test piece, and the ISO (17
The Charpy impact was measured according to 9). (2) Appearance of molded article (%) The pellet obtained in the example was used for IS90B (manufactured by Toshiba).
Was used to perform injection molding under the conditions of a resin temperature of 200 ° C. and a mold temperature of 40 ° C. to prepare a flat plate having a thickness of 3 mm. Using the flat plate, a 60-degree specular gloss was measured in accordance with JIS K7105. This gloss (%) was taken as the appearance of the molded article.

(3) Volume Average Rubber Particle Size (μm) and Particle Size Distribution A 3% by weight DMF solution of the pellets obtained in the examples was prepared, and a laser diffraction / scattering type particle size distribution analyzer (manufactured by Horiba, Ltd.) Volume average rubber particle diameter from data measured using a model (LA700) (obtained by dividing the section from 0.05 μm to 262.4 μm into 64 equally spaced logarithmic widths). And the particle size distribution were determined. (4) Polybutadiene concentration (% by weight) 0.25 g of the pellet obtained in the example was dissolved in 50 ml of chloroform, iodine monochloride was added to react the double bonds in the rubber component, and then potassium iodide was added. The remaining iodine monochloride is converted to iodine and measured using the iodine monochloride method (measuring device: Hiranuma automatic titrator "COMTITE-900") in which back titration is performed with sodium thiosulfate. The rubber component was measured. The unit is% by weight.

(5) Solid weight concentration (% by weight) Syrup (0.200 g) taken out of each reactor
And 1.0% by weight of a polymerization inhibitor (t-butylcatechol)
Dissolve 2 in 30 ml of butanone, and add 1
After drying under reduced pressure for a period of time, the weight of the solid content was determined, and the value was obtained by dividing the weight of the solid content by the total weight of the syrup (0.200 g) previously measured. (6) Average number of graft reaction points

[0035]

(Equation 2)

The values of w (St), w (Bd), Mn (PS) and Mn (PBd) were determined as follows, and the average number of graft reaction points was determined by the following equation (1). First, the syrup taken out of the first reactor was adjusted to a polymer concentration of 3% by weight.
After adding butanone and stirring for 8 hours,
Using a centrifuge set at 00 rpm, centrifugation was performed for 1 hour to separate a soluble portion and an insoluble portion. Here, the 2-butanone-soluble portion contains polystyrene, and the insoluble portion contains polybutadiene and polybutadiene grafted with polystyrene. The 2-butanone-soluble portion was prepared by reprecipitating the polymer component by adding 10 times the volume of methanol of 2-butanone used, filtering, and then reducing the pressure under reduced pressure.
The 2-butanone-soluble part was recovered by drying at 0 ° C. for 12 hours.

Next, the 2-butanone-insoluble portion was taken out of the centrifuge tube, and toluene was added in a volume 30 times the amount of the polymer until the insoluble portion was dried, followed by dispersion for 8 hours with stirring. This sample solution was centrifuged once again under the same conditions as above, and the insoluble portion was taken out. Further, the same amount of toluene as before was added to the insoluble portion, and the mixture was stirred and centrifuged for 8 hours, and the obtained toluene insoluble portion was washed.
After drying for an hour, a toluene-insoluble portion was recovered. This toluene-insoluble portion is polybutadiene grafted with polystyrene. The chloroform solution of this toluene-insoluble part is
After coating on an r plate, chloroform was volatilized and quantitatively determined from an infrared absorption spectrum obtained by transmission measurement. The weight fraction w (St) (%) and the butadiene weight fraction w (Bd) (%) of styrene were determined by Equations 2 and 3.

[0038]

W (St) (%) = 58.5 × Abs (1601) / (Abs (1601) + Abs (725)) + 59.3 × [Abs (1601) / (Abs (1601) + Abs (725)) ² ) Equation 2 w (Bd) (%) = 100−w (St) (%) Equation 3

Here, Abs (1601) and Abs (72
5) is 1601 in the infrared absorption spectrum.
the absorbance in the vicinity cm ^-1 and around 725 cm ^-1. Further, the number average molecular weight (Mn (PS)) of polystyrene, which is a 2-butanone-soluble portion, and the number average molecular weight (Mn (PBd)) of polybutadiene as a raw material were determined by GPC measurement. The measuring device is an online degasser S made by TOSOH
D-8010, a liquid sending pump CCPM, an autosampler AS-8010, a column oven CO-8010, and a differential refractometer RI-8010 were used.

The column is TSKgel G manufactured by TOSOH.
Three MH _HR and TSKgel guardcolumn
H _HR -H was used in combination. The mobile phase solvent is Mn (PS)
Is measured by tetrahydrofuran (Kanto Chemical Reagent,
butylated hydroxytoluene
(BHT) (containing 0.025%), and Mn (PBd) was measured using toluene (Kanto Chemical Reagent). The flow rate and the measurement temperature were both 1.0 ml / min and 40 ° C. Viscotek for data collection and analysis
Corporation's GPC data processing software
Tri-SEC (GPC Module Ver.
0-ac) was used.

The 2-butanone-soluble part and the raw material polybutadiene were stirred at room temperature for about 5 hours using each mobile phase solvent containing 0.5% of BHT, and then left for about 12 hours to obtain about 2 mg / ml. Is prepared and filtered through a PTFE type membrane filter (pore size 0.45 μm).
100 μl was injected into the device. To prepare a GPC calibration curve, a standard polystyrene (A-2500, manufactured by TOSOH) was used.
A-5000, F-1, F-2, F-4, F-10, F
-20, F-40, F-80, F-128, F-38
0, F-850). The mobile phase flow rate was corrected with the BHT peak elution volume as an internal standard.

Mn (PS) is obtained from this calibration curve.
n (PBd) is the molecular weight in terms of polystyrene obtained from this calibration curve, and is expressed by the viscosity formula of polystyrene and polybutadiene (polystyrene: [η] = (11.0 × 10 ⁻³ ) M ^0.725 (ml
/ G), Low-cis polybutadiene: [η] =
(39.0 × 10 ⁻³ ) M ^0.713 (ml / g), source “PO
LYMER HANDBOOK ”) and corrected to polybutadiene.

Example 2 In Example 1, the polybutadiene A was changed to a polybutadiene B (a 5% by weight styrene solution having a viscosity of 2%).
35 cps at a temperature of 5 ° C., the microstructure is 18% by weight of 1,2-vinyl structure, 33% by weight of 1,4-cis structure, 1,4
-Trans structure 49% by weight), the amount of t-butyl peroxybenzoate to 0.0735 parts by weight, and the first reactor outlet in the same manner except that the first reactor temperature shown in Table 1 was used. A solid was obtained. The weight concentration of the solid content at the outlet of the first reactor was 31.0% by weight. When the syrup at the outlet of the first reactor was confirmed with a phase contrast microscope (400 times),
The rubber component was particulate. A pellet-shaped rubber-modified styrene resin composition was obtained in the same manner as in Example 1, except that the temperature control of the polymerization reaction product in the second and third reactors was changed as shown in Table 1. . In Table 1, the rubber components used for the polymerization, the concentration of the initiator, the temperature in each reactor, the solid weight concentration at the outlet of each reactor, and the evaluation of the physical properties of the obtained rubber-modified styrene resin composition were the same as those in Example 1. The results of the test were shown.

Comparative Example 1 A solid content at the outlet of the first reactor was obtained in the same manner as in Example 1 except that the temperature of the first reactor was changed as shown in Table 1. The weight concentration of the solid content at the outlet of the first reactor was 34.5% by weight. Further, the syrup at the outlet of the first reactor was transferred to a phase contrast microscope (4
(00 times), it was found that the rubber component had become particles. A pellet-shaped rubber-modified styrene resin composition was obtained in the same manner as in Example 1, except that the temperature control of the polymerization reaction product in the second and third reactors was changed as shown in Table 1. . Table 1 shows the rubber components, initiator concentrations,
The temperature in each reactor, the solid weight concentration at the outlet of each reactor, and the evaluation of the physical properties of the obtained rubber-modified styrenic resin composition were the same as in Example 1.

Comparative Example 2 In Example 2, the amount of t-butyl peroxybenzoate was changed to 0.098 parts by weight, and
A solid content at the outlet of the first reactor was obtained in the same manner except that the temperature was changed to the reactor temperature. The weight concentration of solids at the outlet of the first reactor was 26.0.
% By weight. Further, when the syrup at the outlet of the first reactor was confirmed with a phase contrast microscope (400 times), it was found that the rubber component had become particles. A pellet-shaped rubber-modified styrene resin composition was obtained in the same manner as in Example 2, except that the temperature control of the polymerization reaction product in the second and third reactors was changed as shown in Table 1. In Table 1, the rubber components used for the polymerization, the concentration of the initiator, the temperature in each reactor, the solid weight concentration at the outlet of each reactor, and the evaluation of the physical properties of the obtained rubber-modified styrene resin composition were the same as those in Example 1. The results of the test were shown.

[0046]

[Table 1]

[0047]

According to the production method of the present invention, it is possible to efficiently produce a rubber-modified styrene resin composition having excellent impact resistance and excellent appearance of a molded article such as gloss.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryuichi Hasegawa 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation Yokkaichi Office (72) Megumi Yonekura 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation Yokkaichi Office F-term (reference) 4J011 DA02 DA05 DB03 DB13 DB15 DB19 DB23 DB28 4J026 AA12 AA13 AA14 AA17 AA45 AA49 AA68 AA69 AA72 AB02 AC01 AC02 AC11 AC12 AC16 AC17 AC32 AC33 AC34 AC36 BA05 BA07 BA08 BA07 BA08 DB15 DB26 DB32 DB38 DB40 EA02 GA01 GA06 GA09

Claims (3)

[Claims] 1. A raw material solution mainly composed of a styrene monomer and a rubber-like polymer is continuously charged into at least one reactor, and a rubber component is granulated simultaneously with the polymerization reaction. In a method of continuously producing a rubber-modified styrenic resin composition by increasing the polymerization conversion rate in a reactor to obtain a reaction product and devolatilizing unreacted monomers from the reaction product, A rubber modification characterized in that the rubbery polymer grafted with the styrene resin in the reaction product at the outlet of the reactor in which the components have become particles is polymerized so that the average number of graft reaction points is 1.0 or more and 2.0 or less. A method for producing a styrene resin composition. 2. The rubber-modified styrenic resin composition according to claim 1, wherein the number of equivalent tanks in the complete mixing tank array model is 10 or less in the reactor used until the rubber component is granulated. Method of manufacturing a product. 3. The method for producing a rubber-modified styrene resin composition according to claim 1, wherein the styrene monomer is styrene and the rubbery polymer is polybutadiene.