JP2011202071A - Styrene-based resin composition and molding of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a practical strength of a molded product obtained by using a styrene- (meth) acrylic resin composition and to improve molding processability in various molding methods and the molded product thereof. To provide.
SOLUTION A styrene monomer (a1), an acrylate ester (a2), a weight average molecular weight having a plurality of branches and having a polymerizable double bond at the tip thereof is 1,000-15. , A multi-branched macromonomer (a3) and a multi-branched copolymer (A) obtained by copolymerizing the styrene-based resin composition, the weight average molecular weight (Mw) of the composition ) Is 300,000 to 600,000, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.7 to 4.0, and the styrenic monomer (a1) and the acrylic Styrenic resin composition having a usage ratio (a1) / (a2) with the acid ester (a2) of 87/13 to 96/4 (mass ratio)

Description

  The present invention relates to a copolymer of a multi-branched macromonomer having a polymerizable double bond at a branched end, a styrene monomer and an acrylate ester. More specifically, the present invention relates to a styrenic resin composition that is excellent in molding processability during molding (injection molding, extrusion molding, blow molding, etc.) and has good productivity.

  Styrene- (meth) acrylic resins have high rigidity, excellent dimensional stability, transparency, and the like, and are widely used as molding materials. However, styrene- (meth) acrylic resins satisfy various application requirements and are still insufficient as molding materials with excellent balance, and various performance improvements are required.

  For example, in the case of an optical system member, in order to suppress hygroscopicity that is a cause of deformation (warp, deflection) of a molded product, it is possible to use a copolymer having a high styrene ratio. The strength may be reduced, and the practical level is not reached. As a method for solving this problem, in particular, focusing on the bending energy of a molded product, in order to obtain a molded product having a large bending energy, a hyperbranched macromonomer, a styrene monomer, and a (meth) acrylic monomer There has been provided a multi-branched styrene- (meth) acrylic copolymer obtained by copolymerizing (see, for example, Patent Document 1).

  However, in recent years, in particular, from the viewpoint of reducing environmental burdens, improvement in productivity has been demanded, and it has been awaited to provide a material with excellent molding processability without deteriorating the strength of the molded product. It is.

JP 2007-284591 A

  This invention is made | formed in view of the above problems, and the subject of this invention is various shaping | molding, maintaining the practical intensity | strength of the molded article obtained using a styrene-acrylic-type resin composition. An object of the present invention is to provide a styrenic resin composition capable of improving the moldability in the method and a molded product thereof.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors copolymerized a multi-branched macromonomer originally developed by the present inventors, a styrene monomer and an acrylate ester at a specific ratio. The present inventors have found that the obtained styrene resin composition having a specific weight average molecular weight and molecular weight distribution can solve the above problems, and have completed the present invention.

  That is, the present invention has a weight average molecular weight of 1,000 having a styrene monomer (a1), an acrylate ester (a2), a plurality of branches, and a polymerizable double bond at the tip. A styrene-based resin composition containing a multi-branched copolymer (A) obtained by copolymerizing ˜15,000 multi-branched macromonomer (a3), and GPC-MALS of the composition The weight average molecular weight (Mw) obtained by the method is 300,000 to 600,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.7 to 4.0. In addition, the use ratio (a1) / (a2) of the styrene monomer (a1) and the acrylate ester (a2) is 87/13 to 96/4 (mass ratio). Resin composition and molded product obtained using the same It is intended to provide.

  The styrenic resin composition obtained in the present invention has a wider molecular weight distribution range than the conventional linear styrenic resin composition. From this, even if it contains an ultrahigh molecular weight component, it is molded. Excellent in properties. In addition, when applying various molding methods using molds, the mold release properties are good, so there is no need to release them by using additives, etc., and there is no surface contamination.・ Productivity is good over time, and the degree of defective products can be reduced. Further, the obtained molded product has a mechanical strength equal to or higher than the conventional one. From these things, it can be used suitably for various casings and optical members that are becoming larger and thinner, and various packaging materials that are mass-produced.

It is process drawing which shows one example of the continuous polymerization line incorporating the tubular reactor which has a static mixing element.

The present invention will be described in detail below.
The styrene resin composition of the present invention comprises a styrene monomer (a1), an acrylate ester (a2), a plurality of branches, and a weight average molecular weight having a polymerizable double bond at the tip thereof. Is a styrene-based resin composition containing a multi-branched copolymer (A) obtained by copolymerizing a multi-branched macromonomer (a3) having a molecular weight of 1,000 to 15,000, The weight average molecular weight (Mw) determined by the GPC-MALS method is 300,000 to 600,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.7 to 4 0.0 and the use ratio (a1) / (a2) of the styrene monomer (a1) and the acrylate ester (a2) is 87/13 to 96/4 (mass ratio). Features.

  The GPC-MALS method is a method for measuring molecular weight using a multi-angle light scattering detector, and is useful for measuring molecular weight in highly branched polymers. In the present invention, GPC-MALS measurement of a styrene-based resin composition is performed using Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF (tetrahydrofuran), flow rate 1.0 ml. / Min. In addition, analysis of measurement of GPC-MALS is performed by analysis software ASTRA of Wyatt, and the weight average molecular weight / number average molecular weight of the styrene resin composition is calculated, and the composition is defined by this value. .

  It is essential that the weight average molecular weight (Mw) obtained by the above-described method of the styrene resin composition of the present invention is 300,000 to 600,000. If the molecular weight is less than 300,000, the strength of the resulting molded product is insufficient, and the releasability at the time of injection molding may be reduced. If it exceeds 600,000, the molding process is performed even if the molecular weight distribution is wide. Insufficient properties, and uneven thickness tends to occur particularly during injection molding.

  Further, the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by the GPC-MALS method of the styrene resin composition is in the range of 2.7 to 4.0. Required. In the case where Mw / Mn is lower than 2.7, it is equivalent to the styrene resin composition having a multi-branched structure that has been provided by the present inventors, and molding processability when various molding methods are applied. Is not suitable for improving productivity. In addition, it is difficult to obtain a product having Mw / Mn exceeding 4.0 by a production method described later.

  Examples of the styrenic monomer (a1) that can be used in the present invention include styrene and derivatives thereof; for example, styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, Alkyl styrene such as butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, halogenated styrene such as fluoro styrene, chloro styrene, bromo styrene, dibromo styrene, iodo styrene, nitro styrene, acetyl styrene, methoxy styrene, etc. You may use individually or in mixture of 2 or more types. Among these, styrene is preferably used from the viewpoint of versatility and excellent reactivity with an acrylic ester (a2) described later.

  The acrylic ester (a2) that can be used in the present invention is not particularly limited, and, for example, an acrylic alkyl ester having an alkyl group having 1 to 6 carbon atoms or a substituted alkyl group is preferable. Here, the substituted alkyl group refers to an alkyl group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, a hydroxyl group or the like, and examples of the halogen atom include fluorine, chlorine, bromine and iodine. Specific examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, hydroxyethyl acrylate, hydroxy acrylate Propyl etc. are mentioned, and may be used alone or in admixture of two or more. Among these, acrylic can be used because the branched structure can be suitably arranged in the obtained multibranched copolymer (A), and the molding processability of the styrene resin composition containing this can be improved. Butyl acid is preferred.

  Further, other monomers having a polymerizable double bond may be used in combination as long as the effects of the present invention are not impaired. Examples of the monomer include various (meth) acrylic compounds, vinyl ethers, vinyl esters, and the like.

  In this invention, when using the said other monomer, it is preferable to use at 5 mass% or less with respect to the total mass of the said styrene-type monomer (a1) and the said acrylic ester (a2).

  The multi-branched macromonomer (a3) used in the present invention is a macromonomer having a plurality of branches and having a polymerizable double bond at the tip thereof and a weight average molecular weight of 1,000 to 15,000. Any structure may be used, and the structure is not particularly limited. From the viewpoint of industrial availability, for example, it is preferable to use a multi-branched macromonomer already disclosed by the present inventors in JP-A-2003-292707.

Examples of the hyperbranched macromonomer include those obtained by any of the following methods (1) to (5).
(1) Multi-branched self-condensation polycondensate obtained by nucleophilic substitution reaction of AB ₂ type monomer having active methylene group and bromine, chlorine, methylsulfonyloxy group or tosyloxy group in one molecule Obtained by introducing a polymerizable double bond by subjecting an unreacted active methylene group or methine group remaining in the polycondensate to a nucleophilic substitution reaction with chloromethylstyrene, bromomethylstyrene or the like. Hyperbranched macromonomer,
(2) A monocarboxylic acid having a compound having one or more hydroxyl groups, a carbon atom adjacent to the carboxyl group being a saturated carbon atom, all hydrogen atoms on the carbon atom being substituted, and two or more hydroxyl groups A hyperbranched macromolecule obtained by reacting with acrylic acid, methacrylic acid, an isocyanate group-containing acrylic compound, 4-chloromethylstyrene, etc. by introducing a polymerizable double bond. monomer,
(3) A multi-branched polymer is prepared by reacting a compound having one or more hydroxyl groups with a cyclic ether compound having one or more hydroxyl groups, and then acrylic acid, methacrylic acid or isocyanate group is contained in the hydroxyl group which is a terminal group of the polymer. A hyperbranched macromonomer obtained by reacting an acrylic compound, 4-chloromethylstyrene, etc., and introducing a polymerizable double bond;
(4) a compound having one or more hydroxyl groups, two or more hydroxyl groups and halogen _atoms, -SO ₂ OCH 3, and hyperbranched polymers by reacting a compound containing -OSO ₂ CH ₃ and the like, and then A multi-branched macromonomer obtained by reacting acrylic acid, methacrylic acid, an isocyanate group-containing acrylic compound, 4-chloromethylstyrene and the like with a hydroxyl group which is a terminal group of the polymer, and introducing a polymerizable double bond;
(5) PAMAM dendrimers in which amide bonds are repeated through nitrogen atoms are reacted with acrylic acid, methacrylic acid, isocyanate group-containing acrylic compounds, 4-chloromethylstyrene, etc. to introduce polymerizable double bonds A hyperbranched macromonomer obtained as described above.

Examples of the AB type ₂ monomer having an active methylene group and bromine, chlorine, methylsulfonyloxy group, tosyloxy group, etc. in one molecule in (1) above include, for example, halogenated alkoxy-phenylacetonitriles or tosyloxy groups. And phenylacetonitriles having

  Examples of the monocarboxylic acid (2) in which the carbon atom adjacent to the carboxyl group is a saturated carbon atom, all the hydrogen atoms on the carbon atom are substituted, and having two or more hydroxyl groups include, for example, dimethylol Propionic acid, α, α-bis (hydroxymethyl) butyric acid, α, α, α-tris (hydroxymethyl) acetic acid, α, α-bis (hydroxymethyl) valeric acid or α, α-bis (hydroxymethyl) propionic acid Etc.

  Examples of the cyclic ether compound having one or more hydroxyl groups in (3) above include 3-ethyl-3- (hydroxymethyl) oxetane, 2,3-epoxy-1-propanol, and 2,3-epoxy-1- Examples include butanol or 3,4-epoxy-1-butanol.

Examples of the compound (2) containing two or more hydroxyl groups, a halogen atom, —SO ₂ OCH ₃ , —OSO ₂ CH _{3 and the} like include 5- (bromomethyl) -1,3-dihydroxybenzene, 2 -Ethyl-2- (bromomethyl) -1,3-propanediol, 2-methyl-2- (bromomethyl) -1,3-propanediol, 2- (bromomethyl) -2- (hydroxymethyl) -1,3- Examples include propanediol.

  The PAMAM dendrimer in the above (5) can be produced, for example, by the technique shown in Japanese Patent Publication No. 6-070132 and Japanese Patent Publication No. 7-043522.

  In addition, it is essential that the weight average molecular weight of the hyperbranched macromonomer (a3) is 1,000 to 15,000. The molecular weight was measured by GPC-MALS measurement method (Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, flow rate 1.0 ml / min). Moreover, the analysis of the measurement of GPC-MALS was performed with the analysis software ASTRA of Wyatt, and the weight average molecular weight was obtained. When the molecular weight is less than 1,000, the introduction amount of the branched structure is insufficient, and the physical properties are close to those of the conventional linear styrene-acrylic copolymer, and a styrene resin composition having a wide molecular weight distribution range defined in the present application is obtained. In some cases, the molded product obtained is difficult to be obtained and the practical strength is insufficient. On the other hand, when the molecular weight is 15,000 or more, it is difficult to handle the hyperbranched macromonomer, and it may be difficult to uniformly copolymerize the styrene monomer (a1) and the acrylate ester (a2). A more preferable molecular weight is 2,500 to 7,000.

  The multi-branched macromonomer (a3) preferably contains 0.1 to 5.5 mmol of polymerizable double bond per gram. Within this range, the introduction amount of the branched structure in the resulting multibranched copolymer (A) can be controlled, and the desired high molecular weight component is appropriately contained while preventing gelation during production, and is wide. It becomes easy to obtain a styrene resin composition having a molecular weight distribution. A more preferable content is in the range of 1.0 to 3.5 mmol. This content is obtained, for example, in the case of a double bond based on methacrylic acid or a derivative thereof, as containing 1 mol of a double bond in the formula amount of methyl methacrylate. In the case of a double bond based on a similar compound, this is the value determined as containing 1 mole of double bond in the formula weight of styrene.

  The styrene resin composition of the present invention comprises a multi-branched copolymer obtained by copolymerizing the styrene monomer (a1), the acrylate ester (a2) and the multi-branched macromonomer (a3). Although the polymer (A) is essential, when this copolymer is synthesized, a linear copolymer of the styrene monomer (a1) and the acrylate ester (a2) Thus, it is obtained as a mixture containing a low-branched copolymer that does not sufficiently contain the multi-branched macromonomer (a3) -derived structure. In the present invention, since the multi-branched copolymer (A) may be essential, it is not necessary to remove such a linear copolymer or a low-branched copolymer. Mw and Mw / Mn ratio can be used as they are as the styrenic resin composition of the present invention. In addition, if Mw and Mw / Mn specified above are not satisfied in one-stage production, a resin obtained by copolymerizing a styrene monomer (a1) and an acrylate ester (a2) is mixed. And can be adjusted.

  In the styrene resin composition of the present invention, the use ratio (a1) / (a2) of the styrene monomer (a1) to the acrylate ester (a2) is 87/13 to 96/4 (mass ratio). Is essential. As described above, even when a resin obtained by separately copolymerizing the styrene monomer (a1) and the acrylate ester (a2) is mixed and adjusted, the styrene monomer in the styrene resin composition is also prepared. It is essential that the mass ratio between the content of the body-derived component and the content of the acrylic ester (a2) -derived component is within the range. When the ratio of the acrylic ester used is lower than 4, the molding processability when various molding methods are applied is insufficient, and the effect of imparting the molding processability intended by the present invention can be expressed. It becomes difficult. Moreover, when the usage-amount of acrylic ester exceeds 13.0, Vicat softening temperature falls and the heat resistance of a molded article is less than a practical range.

  Moreover, it is preferable to use the said hyperbranched macromonomer (a3) by 100-1,000 ppm on a mass basis with respect to the sum total of the said styrene-type monomer (a1) and the said acrylic ester (a2). By blending the raw materials in this range, it becomes easy to obtain a styrene-based resin composition having Mw and Mw / Mn as defined above by one-stage production. From the point which is excellent in the physical property balance of the molded article obtained, butyl acrylate is used as an acrylate ester, and the ratio of use with the styrene monomer (a1) (a1) / butyl acrylate is 92/8 to 96/4 ( (Mass ratio) is more preferable, and the use ratio of the hyperbranched macromonomer (a3) is more preferably in the range of 100 to 500 ppm (mass basis).

  Conventionally, it is known that flexibility (flexibility) is expressed in a molded article using a copolymer obtained by using a styrene monomer (a1) and an acrylate ester (a2) in combination. It was. However, in this case, since the softening point of the copolymer is lowered, the heat resistance may be insufficient or the mechanical strength may not be at a practical level. On the other hand, it has also been known that by using the hyperbranched macromonomer (a3) in combination, a copolymer having excellent fluidity can be obtained even though a high molecular weight copolymer is contained. However, even when a multi-branched macromonomer is used in combination, its fluidity is only good in comparison with a linear resin having a similar weight average molecular weight, and diversification of molded products (upsizing / With the thinning and high design, etc., and with the diversification of molding methods, further workability has been demanded. Furthermore, from the viewpoint of energy reduction, moldability at a lower temperature is also necessary, and in a molding method using a mold, mold release characteristics for preventing resin stains on the mold are also necessary for improving productivity. It is an item. The present invention provides a styrenic resin composition excellent in these performance balances in order to meet such demands.

  The styrene resin composition of the present invention is a styrene resin composition containing the multi-branched copolymer (A) as described above, and the weight average molecular weight determined by the GPC-MALS method of the composition. (Mw) is 300,000 to 600,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) may be 2.7 to 4.0. Various additives may be used in combination depending on the method.

  Examples of the additive include various stabilizers, antiblocking agents, antistatic agents, lubricants, antifogging agents, antibacterial agents, antioxidants, dyes, and ultraviolet absorbers. However, since the styrenic resin composition used in the present invention is excellent in these performances without using mineral oil or the like that has been used for imparting releasability and molding processability, the use of additives However, it is necessary to pay attention to a point different from the method of using the additive in the conventional styrene- (meth) acrylic copolymer.

  As a method for producing the styrene resin composition of the present invention, the styrene monomer (a1), the acrylate ester (a2), and the hyperbranched macromonomer (a3) are copolymerized and specified in the present application. The styrene-based resin composition having a molecular weight / molecular weight distribution range to be used is not particularly limited. From the viewpoint that the target styrene-based resin composition can be efficiently produced by a one-step reaction, it is preferable to adopt a production method already provided by the present inventors in JP-A-2005-053939.

  Specifically, the mixture containing the raw materials is preferably reacted by a solution polymerization method or a melt polymerization method (bulk polymerization method). In this case, it can be carried out without adding an organic solvent. However, it is preferable to use a small amount of an organic solvent in combination because the viscosity of the reaction product is lowered and the molecular weight of the polymer is easy to control.

As the organic solvent that can be used, one having a chain transfer constant of 0.1 × 10 ⁻⁵ to 1 × 10 ⁻⁴ is preferable, and one having a chain transfer constant of 0.2 × 10 ^{−5 to} 0.8 × 10 ^−5. More preferred. For example, toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, anisole, cyanobenzene, dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone and the like are preferable. About the usage-amount, 5 mass parts-50 mass parts are preferable with respect to a total of 100 mass parts of a raw material monomer, and 6 mass parts-20 mass parts are more preferable. In addition, since it is easy to suppress the production | generation of an organic solvent insoluble part, it is preferable to superpose | polymerize using an organic solvent.

  In particular, when it is desired to increase the amount of the multi-branched macromonomer (a3), it is necessary to use the organic solvent from the viewpoint of suppressing gelation. Thereby, it is possible to increase the addition amount of the multibranched macromonomer shown above.

  In starting the polymerization, a radical polymerization initiator is used. As such an initiator, those having a half-life of 10 hours are preferably 75 to 140 ° C, more preferably 85 to 135 ° C. For example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2-bis (4,4-di-butylperoxycyclohexyl) propane, etc. Hydroperoxides such as peroxyketals, cumene hydroperoxide, t-butyl hydroperoxide, dialkyl peroxides such as di-t-butyl peroxide, dicumyl peroxide, di-t-hexyl peroxide, Diacyl peroxides such as benzoyl peroxide and disinamoyl peroxide, peroxyesters such as t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, and t-butyl peroxy isopropyl monocarbonate, N , N'-Azobisisobutylnitrate N, N′-azobis (cyclohexane-1-carbonitrile), N, N′-azobis (2-methylbutyronitrile), N, N′-azobis (2,4-dimethylvaleronitrile), N, N′-azobis [2- (hydroxymethyl) propionitrile] and the like can be mentioned, and these can be used alone or in combination.

  As these usage-amounts, 50 ppm-1000 ppm are preferable on a mass basis with respect to the monomer synthetic | combination mass of a raw material, More preferably, it is 100-500 ppm.

  Further, a chain transfer agent may be added so that the molecular weight of the styrene resin composition does not become excessively large. As the chain transfer agent, a monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer agents can be used. Examples of the monofunctional chain transfer agent include alkyl mercaptans and thioglycolic acid esters.

  Polyfunctional chain transfer agents such as ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, etc. are esterified with thioglycolic acid or 3-mercaptopropionic acid. The thing which was done is mentioned.

  The molded product of the present invention is not limited in any way other than using the styrenic resin composition of the present invention. For example, a molded method such as injection, extrusion, blow, compression, etc. is applied, and an injection molded product, Molded into plates, sheets, films, etc. In particular, it can be suitably used for applications that are mass-produced, for example, transparent large-sized injection-molded articles, etc., because the styrenic resin composition of the present invention is excellent in productivity such as excellent moldability and releasability. .

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” represents “mass%”.

The evaluation method is as follows.
[GPC-MALS measurement conditions]
GPC-MALS measurement of the styrene resin composition was performed under the conditions of Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, flow rate 1.0 ml / min. . Moreover, the analysis of the measurement of GPC-MALS was performed with the analysis software ASTRA of Wyatt, and the weight average molecular weight, the number average molecular weight, etc. about the styrene resin composition were calculated | required.

[Melt Mass Flow Rate (MFR) Measurement Method]
The measurement was performed according to JIS K7210. The measurement conditions are a temperature of 200 ° C. and a load of 49N.
[Charpy impact strength]: Measured according to JIS K7111.
[Vicat softening temperature]: Measured according to JIS K7206: 99.

[Injection moldability]
A pudding type container was molded by a 150-ton injection molding machine manufactured by Nippon Steel Works, and evaluated based on the following evaluation criteria.
Easy to mold containers and no uneven thickness: ◎
Container molding is relatively easy and there is no uneven thickness: ○
Container molding is relatively easy, but there is uneven thickness: △
Container formation is difficult and there is uneven thickness: ×

[Sheet forming processability]
Using a sheet extruder (screw diameter 30 mm), the resin pellets were extruded at a molten resin temperature of 210 ° C. to 230 ° C. and an extrusion speed of 0.8 to 1 m / min to produce a sheet sample having a thickness of 0.4 mm. Next, immediately after heating this sheet sample at a heating temperature of 290 ° C. to 300 ° C. and a heating time of 10 seconds to 30 seconds using a vacuum forming machine, the length of the sag at the center of the sheet based on the sheet surface before heating the sheet The moldability was evaluated based on the following evaluation criteria from the length of the sheet hanging with respect to the heating time.
When the heating time is 20 seconds, the sagging amount is less than 20 mm, ◎ is 20 to less than 40 mm, and x is 40 mm or more.
When the heating time is 30 seconds, the sagging amount is less than 30 mm, が is less than 30 to 60 mm, and x is 60 mm or more.
However, when the evaluation with respect to one of the heating times was x and the other one was ○ or ◎, the evaluation was Δ.

(Releasability)
A box shape of 20 cm × 15 cm × 4 cm was formed by a 150-ton injection molding machine manufactured by Nippon Steel Works, and evaluated based on the following evaluation criteria.
◎: Easy to release after 50 consecutive shots ○: Easy to release after 30 consecutive shots △: Difficult to release after 10 consecutive shots ×: Difficult to release from 1 to 2 continuous shots

[Practical heat resistance]
A box shape of 20cm x 15cm x 4cm was molded by a 150-ton injection molding machine manufactured by Nippon Steel Works. When the molded product was left to stand for 1 hour at an ambient temperature of 70 ° C, ◎, almost no deformation The case where no was observed was marked with ◯, and when the degree of deformation was obvious and the degree was large, the case was marked with x.

Reference Example 1 Synthesis of Multibranched Macromonomer (a3-1) <Synthesis of Multibranched Polyether Polyol>
To a 2 liter flask equipped with a stirrer, thermometer, dropping funnel and condenser, 50.5 g of ethoxylated pentaerythritol (5 mol-ethylene oxide-added pentaerythritol) and 1 g of BF ₃ diethyl ether solution (50%) were added at room temperature. Heated to 110 ° C. To this, 450 g of 3-ethyl-3- (hydroxymethyl) oxetane was slowly added over 25 minutes while controlling the exotherm due to the reaction. When the exotherm had subsided, the reaction mixture was further stirred at 120 ° C. for 3 hours and then cooled to room temperature. The resulting multi-branched polyether polyol had a weight average molecular weight of 3,000 and a hydroxyl value of 530.

<Synthesis of a hyperbranched macromonomer having a methacryloyl group and an acetyl group>
In a reactor equipped with a Dean-Stark decanter equipped with a stirrer, a thermometer, a condenser, and a gas introduction tube, 50 g of the multi-branched polyether polyol obtained in the above-mentioned <Synthesis of multi-branched polyether polyol 1>, methacrylic acid 13 .8 g, 150 g of toluene, 0.06 g of hydroquinone and 1 g of paratoluenesulfonic acid, and stirring under normal pressure while blowing 7% oxygen-containing nitrogen (v / v) into the mixed solution at a rate of 3 ml / min. Heated. The amount of heating was adjusted so that the amount of distillate in the decanter was 30 g per hour, and heating was continued until the amount of dehydration reached 2.9 g. After completion of the reaction, the mixture was cooled once, 36 g of acetic anhydride and 5.7 g of sulfamic acid were added, and the mixture was stirred at 60 ° C. for 10 hours. Thereafter, in order to remove the remaining acetic acid and hydroquinone, it was washed with 50 g of 5% aqueous sodium hydroxide solution four times, and further washed once with 50 g of 1% aqueous sulfuric acid solution and twice with 50 g of water. To the obtained organic layer, 0.02 g of methoquinone was added, the solvent was distilled off under reduced pressure while introducing 7% oxygen-containing nitrogen (v / v), and a multibranched macromonomer having an isopropenyl group and an acetyl group ( a3-1) 60 g was obtained. The obtained multibranched macromonomer (a3-1) has a weight average molecular weight of 3,900, and the introduction ratio of isopropenyl group and acetyl group into the multibranched polyether polyol is 30 mol% and 62 mol%, respectively. there were. Therefore, the introduction amount of the polymerizable double bond is 1.50 mmol / g.

(Reference Example 2) Synthesis of hyperbranched macromonomer (a3-2) <Synthesis of hyperbranched macromonomer having a styryl group and an acetyl group>
In a reactor equipped with a stirrer, a condenser equipped with a drying tube, a dropping funnel and a thermometer, 50 g of the multibranched polyether polyol obtained in the above-mentioned <Synthesis of multibranched polyether polyol 1>, 100 g of tetrahydrofuran and sodium hydride 4.3 g was added and stirred at room temperature. To this was added dropwise 26.7 g of 4-chloromethylstyrene over 1 hour, and the resulting reaction mixture was further stirred at 50 ° C. for 4 hours. After completion of the reaction, the reaction mixture was once cooled, 34 g of acetic anhydride and 5.4 g of sulfamic acid were added, and the mixture was stirred at 60 ° C. for 10 hours. Thereafter, the tetrahydrofuran was distilled off under reduced pressure, the resulting mixture was dissolved in 150 g of toluene, washed with 50 g of 5% aqueous sodium hydroxide solution to remove the remaining acetic acid, and further 50 g of 1% aqueous sulfuric acid solution. And once with 50 g of water. The solvent was distilled off from the obtained organic layer under reduced pressure to obtain 70 g of a hyperbranched macromonomer (a3-2) having a styryl group and an acetyl group. The obtained multibranched macromonomer (a3-2) had a weight average molecular weight of 4,800, and the introduction ratios of styryl groups and acetyl groups into the multibranched polyether polyol were 38 mol% and 57 mol%, respectively. It was. Therefore, the introduction amount of the polymerizable double bond is 1.31 mmol / g.

Reference Example 3 Synthesis of Multibranched Macromonomer (a3-3) <Synthesis of Multibranched Macromonomer Having a Methacryloyl Group and an Acetyl Group>
A four-necked flask was equipped with a stirrer, pressure gauge, condenser and saucer, to which 308.9 g of ethoxylated pentaerythritol and 0.46 g of sulfuric acid were added. Then, it heated to 140 degreeC and 460.5g of 2, 2- di (hydroxymethyl) propionic acid was added over 10 minutes. After 2,2-di (hydroxymethyl) propionic acid is completely dissolved and becomes a transparent solution, the pressure is reduced to 30 to 40 mmHg and the reaction is continued for 4 hours while stirring and the acid value becomes 7.0 mgKOH / g. I let you. Thereafter, 921 g of 2,2-di (hydroxymethyl) propionic acid and 0.92 g of sulfuric acid were added to the reaction solution over 15 minutes to obtain a transparent solution, and then the pressure was reduced to 30 to 40 mmHg, while stirring. The polyester polyol was obtained by reacting for a period of time. In a reaction vessel equipped with a 7% oxygen introduction tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of the polyester polyol produced above, 1.25 g of dibutyltin oxide, and 100 g of methyl methacrylate having an isopropenyl group And 0.05 g of hydroquinone were added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. The amount of heating is adjusted so that the amount of distillate in the decanter is 15 to 20 g per hour, the distillate in the decanter is taken out every hour, and the corresponding amount of methyl methacrylate is added for 4 hours. Reacted. After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 10 g of acetic anhydride and 2 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 70 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.0045 g of methoquinone was added, and the solvent was distilled off while introducing 7% oxygen under reduced pressure to obtain 11 g of a hyperbranched macromonomer having an isopropenyl group and an acetyl group. The resulting multi-branched macromonomer (a3-3) had a weight average molecular weight of 3,000, a number average molecular weight of 2,100, and isopropenyl group and acetyl group introduction rates of 55 mol% and 36 mol%, respectively. It was. Therefore, the introduction amount of the polymerizable double bond is 2.00 mmol / g.

Reference Example 4 Synthesis of hyperbranched macromonomer (a3-4) <Synthesis of PAMAM dendrimer having a styryl group>
To a reactor equipped with a stirrer, a condenser equipped with a drying tube, a dropping funnel and a thermometer, 50 g of a methanol solution (20%) of PAMAM dendrimer (Generation 2.0: manufactured by Dentritech) was added and stirred under reduced pressure. Methanol was distilled off. Subsequently, 50 g of tetrahydrofuran and 3.0 g of finely divided potassium hydroxide were added, and the mixture was stirred at room temperature. 4-chloromethylstyrene 7.0g was dripped at this over 10 minutes, and the obtained reaction mixture was further stirred at 50 degreeC for 3 hours. After completion of the reaction, the mixture was cooled and the solid was filtered, and then tetrahydrofuran was distilled off under reduced pressure to obtain 13 g of a PAMAM dendrimer having a styryl group. The resulting dendrimer had a styryl group content (introduced amount of polymerizable double bond) of 2.7 mmol / gram. The weight average molecular weight of the obtained multibranched macromonomer (a3-4) was 4,050.

Reference Example 5 Synthesis of Multibranched Macromonomer (a3-5) <Multibranched Polyether Polyol Having Styryl Group and Acetyl Group>
A light-shielding reaction vessel equipped with a stirrer, a condenser, a light-shielding dropping funnel and a thermometer, and capable of nitrogen sealing. Under nitrogen flow, anhydrous 1,3,5-trihydroxybenzene 0.5 g, potassium carbonate 29 g, 18-crown -6 2.7 g and acetone 180 g were added, and a solution composed of 21.7 g of 5- (bromomethyl) -1,3-dihydroxybenzene and 180 g of acetone was added dropwise over 2 hours while stirring. Thereafter, the mixture was heated and refluxed with stirring until 5- (bromomethyl) -1,3-dihydroxybenzene disappeared. Thereafter, 9.0 g of 4-chloromethylstyrene was added, and the mixture was further heated and refluxed with stirring until the disappearance. Thereafter, 4 g of acetic anhydride and 0.6 g of sulfamic acid were added to the reaction mixture, and the mixture was stirred overnight at room temperature. After cooling, the solid in the reaction mixture was removed by filtration, and the solvent was distilled off under reduced pressure. The resulting mixture was dissolved in dichloromethane and washed three times with water, and then the dichloromethane solution was added dropwise to hexane to precipitate the product. This was filtered and dried to obtain 12 g of a hyperbranched macromonomer (a3-5) having a styryl group and an acetyl group. The weight average molecular weight was 3,200, and the styryl group content was 3.5 mmol / gram.

Example 1
In this example, an apparatus arranged as shown in FIG. 1 was used. A mixed solution containing styrene, butyl acrylate, a solvent, and the like was supplied to a stirring reactor (2) by a plunger pump (1). Then, it supplied to the circulation polymerization line (I) with the gear pump (3). The circulation polymerization line (I) is used to circulate the 2.5 inch inner diameter tubular reactor (SMX static mixer manufactured by Gebrüu Sulzer, Switzerland) (4), (5), (6) and the mixed solution in order from the inlet. Gear pump (7). The reaction volume of (4) to (6) is about 20L. Between the tubular reactor (6) and the gear pump (7), there is an outlet that leads to the non-circulating polymerization line (II). Tubular reactors (8), (9), (10) and a gear pump (11) similar to the above are connected in series from the inlet to the non-circulating polymerization line (II). The reaction volume of (8) to (10) is about 16L.

93.5 parts of styrene, 6.5 parts of butyl acrylate, 7 parts of ethylbenzene, 300 ppm of the hyperbranched macromonomer (a3-1) of Reference Example 1 with respect to 100 parts in total of styrene and butyl acrylate, a polymerization initiator [ 1,2-bis (4,4-di-t-butylperoxycyclohexyl) propane] was prepared by adjusting a mixed solution consisting of 150 ppm with respect to a total of 100 parts of styrene and butyl acrylate, and using the apparatus shown in FIG. Polymerization was continuously performed under the following conditions.
Feed rate of mixed solution: 9.0 liter / hour Reaction temperature in stirred reactor: 116 ° C.
Reaction temperature in circulation polymerization line (I): 120 ° C
Reaction temperature in non-circulation polymerization line (II): 155 to 170 ° C.

  The mixed solution obtained by polymerization was heated with a heat exchanger at 260 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene resin composition. The polymerization average molecular weight Mw was 380,000, and MFR was 4.0 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 2
A styrene resin composition was obtained in the same manner as in Example 1 except that the multibranched macromonomer (a3-2) was used instead of the multibranched macromonomer (a3-1) in Example 1. The polymerization average molecular weight Mw was 350,000, and the MFR was 3.9 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 3
A styrene resin composition was obtained in the same manner as in Example 1 except that the multi-branched macromonomer (a3-3) was used instead of the multibranched macromonomer (a3-1) in Example 1. The polymerization average molecular weight Mw was 390,000, and MFR was 4.0 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 4
A styrene resin composition was obtained in the same manner as in Example 1 except that the multibranched macromonomer (a3-4) was used instead of the multibranched macromonomer (a3-1) in Example 1. The polymerization average molecular weight Mw was 360,000, and MFR was 4.0 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 5
A styrene resin composition was obtained in the same manner as in Example 1 except that the multibranched macromonomer (a3-5) was used instead of the multibranched macromonomer (a3-1) in Example 1. The polymerization average molecular weight Mw was 320,000, and MFR was 3.9 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 6
A styrene resin composition was obtained in the same manner as in Example 1 except that the amount of the hyperbranched macromonomer (a3-1) added in Example 1 was changed to 100 ppm. The polymerization average molecular weight Mw was 340,000, and MFR was 4.3 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 7
A styrene resin composition was obtained in the same manner as in Example 1 except that the amount of the hyperbranched macromonomer (a3-1) added in Example 1 was changed to 500 ppm. The polymerization average molecular weight Mw was 460,000, and the MFR was 3.6 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 8
A styrenic resin composition was obtained in the same manner as in Example 2 except that the amount of the hyperbranched macromonomer (a3-2) added in Example 2 was changed to 100 ppm. The polymerization average molecular weight Mw was 310,000, and MFR was 4.4 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.7.

Example 9
A styrenic resin composition was obtained in the same manner as in Example 2 except that the amount of the hyperbranched macromonomer (a3-2) added in Example 2 was changed to 500 ppm. The polymerization average molecular weight Mw was 430,000, and the MFR was 3.5 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 10
A styrene resin composition was obtained in the same manner as in Example 3 except that the amount of the hyperbranched macromonomer (a3-3) added in Example 3 was 100 ppm. The polymerization average molecular weight Mw was 360,000, and MFR was 4.6 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 11
A styrene resin composition was obtained in the same manner as in Example 3 except that the amount of the hyperbranched macromonomer (a3-3) added in Example 3 was changed to 500 ppm. The polymerization average molecular weight Mw was 510,000, and MFR was 3.3 g / 10 min. Moreover, ratio Mw / Mn of the weight average molecular weight and the number average molecular weight was 3.0.

Example 12
A styrenic resin composition was obtained in the same manner as in Example 4 except that the amount of the hyperbranched macromonomer (a3-4) added in Example 4 was changed to 100 ppm. The polymerization average molecular weight Mw was 330,000, and MFR was 4.3 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 13
A styrene resin composition was obtained in the same manner as in Example 4 except that the amount of the hyperbranched macromonomer (a3-4) added in Example 4 was changed to 500 ppm. The polymerization average molecular weight Mw was 440,000, and the MFR was 3.2 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 14
A styrenic resin composition was obtained in the same manner as in Example 5 except that the amount of the hyperbranched macromonomer (a3-5) added in Example 5 was changed to 100 ppm. The polymerization average molecular weight Mw was 310,000, and MFR was 4.4 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 15
A styrene resin composition was obtained in the same manner as in Example 5 except that the amount of the hyperbranched macromonomer (a3-5) added in Example 5 was changed to 500 ppm. The average molecular weight Mw was 400,000, and the MFR was 3.4 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 3.3.

Example 16
A styrene resin composition was obtained in the same manner as in Example 1 except that the amount of butyl acrylate added in Example 1 was 4.5 parts. The polymerization average molecular weight Mw was 330,000, and MFR was 4.2 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 17
A styrene resin composition was obtained in the same manner as in Example 1 except that the amount of butyl acrylate added in Example 1 was 12.5 parts. The polymerization average molecular weight Mw was 440,000, and MFR was 4.0 / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 18
A tylene-based resin composition was obtained in the same manner as in Example 2, except that the amount of butyl acrylate added in Example 2 was 4.5 parts. The polymerization average molecular weight Mw was 320,000, and MFR was 4.0 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.7.

Example 19
A styrene resin composition was obtained in the same manner as in Example 2 except that the amount of butyl acrylate added in Example 2 was 12.5 parts. The average molecular weight Mw was 430,000, and the MFR was 4.2 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 20
A styrene resin composition was obtained in the same manner as in Example 3 except that the amount of butyl acrylate added in Example 3 was 4.5 parts. The polymerization average molecular weight Mw was 360,000, and MFR was 4.0 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 21
A styrene resin composition was obtained in the same manner as in Example 3 except that the amount of butyl acrylate added in Example 3 was 12.5 parts. Polymerization average molecular weight Mw was 470,000, and MFR was 4.2 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 22
A styrene resin composition was obtained in the same manner as in Example 4 except that the amount of butyl acrylate added in Example 4 was 4.5 parts. The polymerization average molecular weight Mw was 330,000, and MFR was 3.9 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.7.

Example 23
A styrene resin composition was obtained in the same manner as in Example 4 except that the amount of butyl acrylate added in Example 4 was 12.5 parts. The polymerization average molecular weight Mw was 440,000, and the MFR was 4.1 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 24
A styrene resin composition was obtained in the same manner as in Example 5 except that the amount of butyl acrylate added in Example 5 was 4.5 parts. The polymerization average molecular weight Mw was 310,000, and MFR was 3.7 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.9.

Example 25
A styrene resin composition was obtained in the same manner as in Example 5 except that the amount of butyl acrylate added in Example 5 was 12.5 parts. The polymerization average molecular weight Mw was 460,000, and the MFR was 4.6 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 3.6.

Example 26
A styrene resin composition was obtained in the same manner as in Example 6 except that the amount of butyl acrylate added in Example 6 was 4.5 parts. The polymerization average molecular weight Mw was 310,000, and MFR was 3.8 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.7.

Example 27
A styrene resin composition was obtained in the same manner as in Example 6 except that the amount of butyl acrylate added in Example 6 was 12.5 parts. The average molecular weight Mw was 400,000, and the MFR was 4.4 g / 10 minutes. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 28
A styrene resin composition was obtained in the same manner as in Example 7 except that the amount of butyl acrylate added in Example 7 was 4.5 parts. The average molecular weight Mw was 400,000, and the MFR was 3.5 g / 10 min. The ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Example 29
A styrene resin composition was obtained in the same manner as in Example 7 except that the amount of butyl acrylate added in Example 7 was 12.5 parts. The polymerization average molecular weight Mw was 580,000, and MFR was 4.1 g / 10 min. Moreover, ratio Mw / Mn of the weight average molecular weight and the number average molecular weight was 3.0.

Comparative Example 1
Using the same reactor as in Example 1, 98 parts of styrene, 2 parts of butyl acrylate, 6 parts of ethylbenzene, and 100 parts of the multi-branched macromonomer (a3-1) of Reference Example 1 in total of styrene and butyl acrylate 100 ppm of the polymerization initiator [2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane] was prepared by adjusting a mixed solution of 150 ppm with respect to a total of 100 parts of styrene and butyl acrylate. Polymerization was carried out under the same conditions as in Example 1.

  The mixed solution obtained by polymerization was heated with a heat exchanger at 250 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene-based resin composition. The obtained styrene-based resin composition had a weight average molecular weight Mw of 370,000, an MFR of 1.5 g / 10 minutes, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight of 3.2.

Comparative Example 2
Using the same reactor as in Example 1, 98 parts of styrene, 2 parts of butyl acrylate, 7 parts of ethylbenzene, and 100 parts of the multi-branched macromonomer (a3-1) of Reference Example 1 in total of styrene and butyl acrylate In contrast, 100 ppm of a polymerization initiator, t-butyl peroxybenzoate, was prepared by continuously preparing a mixture of 300 ppm with respect to a total of 100 parts of styrene and butyl acrylate under the following conditions using the apparatus shown in FIG. It was.
Feed rate of mixed solution: 9.0 liter / hour Reaction temperature in stirred reactor: 130 ° C
Reaction temperature in circulating polymerization line (I): 130 ° C
Reaction temperature in non-circulation polymerization line (II): 135 to 145 ° C
The mixed solution obtained by polymerization was heated with a heat exchanger at 260 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene resin composition. The obtained styrene-based resin composition had a weight average molecular weight Mw of 270,000, an MFR of 3.5 g / 10 minutes, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight of 2.2.

Comparative Example 3
100 parts of styrene, 7 parts of ethylbenzene, 300 ppm of the hyperbranched macromonomer (a3-1) of Reference Example 1 with respect to 100 parts of styrene, a polymerization initiator (2,2-bis (4,4-di-t-butylper The same conditions as in Example 1 except that a mixture of 150 ppm of oxycyclohexyl) propane) with respect to 100 parts of styrene was prepared and the reaction temperature in the non-circular polymerization line (II) was in the range of 145 to 155 ° C. And polymerized. The mixed solution obtained by polymerization was heated with a heat exchanger at 260 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene resin composition. The obtained styrene-based resin composition had a weight average molecular weight Mw of 280,000, an MFR of 2.7 g / 10 minutes, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight of 2.4.

Comparative Example 4
87.5 parts of styrene, 12.5 parts of butyl acrylate, 7 parts of ethylbenzene, 300 ppm of the hyperbranched macromonomer (a3-1) of Reference Example 1 with respect to a total of 100 parts of styrene and butyl acrylate, a polymerization initiator ( A mixture of 150 ppm of 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane) was prepared with respect to 100 parts of styrene, and the reaction temperature in the acyclic polymerization line (II) was set to 145- Polymerization was carried out under the same conditions as in Example 1 except that the temperature range was 155 ° C. The mixed solution obtained by polymerization was heated with a heat exchanger at 260 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene resin composition. The obtained styrene-based resin composition had a weight average molecular weight of 610,000, an MFR of 3.8 g / 10 min, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 2.8.

Comparative Example 5
85 parts of styrene, 15 parts of butyl acrylate, 7 parts of ethylbenzene, 300 ppm of the hyperbranched macromonomer (a3-1) of Reference Example 1 with respect to a total of 100 parts of styrene and butyl acrylate, a polymerization initiator (2,2- A mixture of bis (4,4-di-t-butylperoxycyclohexyl) propane) consisting of 150 ppm with respect to 100 parts of styrene was prepared, and the reaction temperature in the non-circular polymerization line (II) was in the range of 145 to 155 ° C. Polymerization was carried out under the same conditions as in Example 1 except that. The mixed solution obtained by polymerization was heated with a heat exchanger at 260 ° C., and after removing volatile components under a reduced pressure of 5 kPa, pelletized to obtain a styrene resin composition. The obtained styrene-based resin composition had a weight average molecular weight Mw of 590,000, an MFR of 3.2 g / 10 minutes, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight of 2.9.

(1): Pusher pump (2): Stirred reactor (3): Gear pump (4): Tubular reactor with static mixing element (5): Tubular reactor with static mixing element (6): Static Tubular reactor with static mixing element (7): gear pump (8): tubular reactor with static mixing element (9): tubular reactor with static mixing element (10): tubular with static mixing element Reactor (I): Circulation polymerization line (II): Non-circulation polymerization line

Claims (4)

A styrene monomer (a1), an acrylate ester (a2), a polymer having a plurality of branches and a weight average molecular weight of 1,000 to 15,000 having a polymerizable double bond at the tip. A styrenic resin composition containing a multi-branched copolymer (A) obtained by copolymerizing a branched macromonomer (a3),
The weight average molecular weight (Mw) calculated | required by GPC-MALS method of this composition is 300,000-600,000, and ratio (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) is 2. 7 to 4.0, and the use ratio (a1) / (a2) of the styrene monomer (a1) to the acrylate ester (a2) is 87/13 to 96/4 (mass ratio). A styrene-based resin composition characterized by being. The usage ratio of the multi-branched macromonomer (a3) is 100 to 1,000 ppm on a mass basis with respect to the total of the styrene monomer (a1) and the acrylate ester (a2). The styrenic resin composition as described. The styrenic resin composition according to claim 1 or 2, wherein the acrylic ester (a2) is butyl acrylate. A molded article obtained by using the styrenic resin composition according to any one of claims 1 to 3.

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