JPWO2017022498A1 - Styrene resin composition, foam sheet and molded body using the same - Google Patents

Abstract

A resin composition containing a polystyrene resin (A), a polyphenylene ether resin (B), and a foaming agent (C), wherein the polystyrene resin (A) has a structure derived from a styrene monomer (a2), It is a multi-branched resin having a structure derived from methacrylic acid (a3), and (1) the weight average molecular weight determined by the GPC-MALS method is 200,000 to 700,000, and (2) determined by the GPC-MALS method. In a logarithmic graph with the molecular weight obtained as the horizontal axis and the inertial radius as the vertical axis, the slope in the region of the molecular weight of 250,000 to 10 million is 0.30 to 0.45, the moldability and heat resistance The present invention also provides a styrene-based resin composition capable of suitably obtaining a foamed sheet having a good balance between oil resistance and strength and good productivity, and a foamed sheet and a molded body using the same.

Description

  The present invention relates to a styrene resin composition containing a polystyrene resin having a specific multi-branched structure and a polyphenylene ether resin, and a foam of the resin composition, and more specifically, molded from a conventional styrene foam sheet. The present invention relates to a foamed sheet having a good balance of heat resistance, heat resistance, oil resistance and strength, and a molded body using the same.

  Styrenic resin sheets are mainly used as food packaging containers because of their excellent transparency and rigidity. In general, the styrene resin is a resin that can be easily foamed, can reduce the weight of the molded body, and can greatly contribute to resource saving. Furthermore, a recycling system has been established, and the recycling rate is higher than other materials.

  However, in recent years, due to the shortening of range-up time at convenience stores, microwave ovens with high output (high wattage) have been used, and applications that increase the range of lunch boxes that contain a large amount of liquid components have also increased. For this reason, higher heat resistance has been demanded for the bottom material using a food container lid and a foam sheet. When such heat resistance is required, it has been proposed to use a mixture of a polystyrene resin and a polyphenylene ether resin as a resin to be used (see, for example, Patent Document 1). However, the resin composition provided in Patent Document 1 has a poor balance between fluidity and heat resistance, and the mold reproducibility at the time of secondary molding after forming a foamed sheet is insufficient. Furthermore, there has been a problem in resistance to oil components represented by long chain fatty acids when used as food packaging materials.

  Moreover, as a method for improving the heat resistance of the styrene resin sheet, for example, a styrene-methacrylic acid copolymer obtained by copolymerizing 94 to 96% by mass of styrene monomer and 4 to 6% by mass of methacrylic acid is used. There has been proposed a method of using a foam sheet (see, for example, Patent Document 2). Although this method produces a certain effect with respect to heat resistance, the secondary formability of the foam sheet and the strength of the molded body may be insufficient, and this is a thing that balances heat resistance, moldability, and strength. It was.

  Furthermore, it is also proposed to make a heat-resistant resin composition by mixing a polystyrene resin and a resin composed of a styrene monomer and an acrylic acid monomer with respect to a polyphenylene ether resin (for example, Patent Document 3). reference). However, when trying to increase the proportion of the resin composed of styrene monomer and acrylic acid monomer used together to substantially increase heat resistance, the extrusion characteristics at the time of melt-kneading will be inferior, and this will be improved. For this reason, ordinary polystyrene must be used in combination, and as a result, in order to balance the heat resistance and moldability, further improvements are required.

JP 2003-012847 A JP 2013-221128 A JP 2012-140549 A

  In view of these circumstances, the problem to be solved by the present invention is a styrenic resin composition capable of suitably obtaining a foam sheet having a good balance of moldability, heat resistance, oil resistance, and strength and good productivity. An object of the present invention is to provide a foamed sheet having the performance and a molded body using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that a resin containing a styrene-methacrylic acid resin having a plurality of branched structures, a polyphenylene ether resin (B), and a foaming agent (C). The present inventors have found that the above problems can be solved by using the composition, and have completed the present invention.

That is, the present invention is a resin composition containing a polystyrene resin (A), a polyphenylene ether resin (B), and a foaming agent (C), wherein the polystyrene resin (A) is
It is a multi-branched resin having a structure derived from styrene monomer (a2) and a structure derived from methacrylic acid (a3), and (1) the weight average molecular weight determined by GPC-MALS method is 150,000 to 700,000 ,
(2) In a log-log graph with the molecular weight determined by the GPC-MALS method as the horizontal axis and the inertial radius as the vertical axis, the slope in the region of the molecular weight of 250,000 to 10 million is 0.30 to 0.55. The present invention provides a characteristic styrenic resin composition, a foamed sheet obtained by foaming the composition, and a molded product formed by molding the foamed sheet.

  The styrene resin composition of the present invention can improve moldability by introducing a multi-branched structure into a styrene-methacrylic acid copolymer, and maintains a high melt viscosity of the styrene-methacrylic acid copolymer. It is possible to increase the molecular weight and impart heat resistance higher than conventional. Therefore, even if the proportion of polyphenylene ether resin used in the conventional alloy of styrene resin and polyphenylene ether resin is reduced, the foamed sheet is provided with the same level of strength and heat resistance while maintaining the same moldability. can do. Also, along with the reduction in the use ratio of polyphenylene ether resins, it is possible to improve the odor derived from polyphenylene ether resins and to exhibit oil resistance, so it is suitable for food applications such as heating in a microwave oven. Can be used.

It is the chromatograph which measured molecular weight by GPC-MALLS. It is a log-log graph with the horizontal axis representing the molecular weight of the resin determined from GPC-MALLS and the vertical axis representing the radius of inertia. It is a simplified apparatus diagram for continuous bulk polymerization of polystyrene resin.

The styrene resin composition of the present invention will be described in detail below.
The polystyrene resin (A) used in the present invention is a multi-branched resin having a structure derived from a styrene monomer (a2) and a structure derived from methacrylic acid (a3). The derived structure refers to a structure in which a polymerizable group (vinyl group) in the styrene monomer (a2) or methacrylic acid (a3) is converted into a single bond by reaction. The term “multi-branched” does not mean that the compound is a straight-chain polymer but a plurality of chain branch points exist in one molecule.

[GPC-MALLS]
When the molecular weight of the polystyrene resin (A) used in the present invention is measured by GPC-MALLS, for example, the chromatograph shown in FIG. 1 is obtained. The polystyrene-based resin (A) based on this measurement result must have a weight average molecular weight in the range of 150,000 to 700,000, and in the range of 200,000 to 500,000, it is excellent in moldability and obtained. This is preferable from the viewpoint of excellent balance of strength and the like of the molded article.

  In FIG. 1, the peak on the low molecular weight side is P1, and the peak on the high molecular weight side is P2. The peak P1 is presumed to contain a linear resin and a resin with a low degree of branching. The peak P2 is presumed to contain mainly a multi-branched resin having a high degree of branching. The region of peak P2 includes a perpendicular line drawn from the highest point of peak P2 to the baseline (a dotted line drawn substantially parallel to the volume axis in FIG. 1), a baseline, and a molecular weight curve on the left side from the highest point. And a molecular weight curve formed when the region (1) is folded to the right side with the perpendicular as the axis of symmetry (in FIG. 1, a virtual line indicated by a dotted line on the right side of the perpendicular). This is a region formed by a region (2) surrounded by a molecular weight curve), a perpendicular, and a base line. The region of peak P1 is a portion obtained by subtracting the region of peak P1 composed of the region (1) and region (2) from the region surrounded by the molecular weight curve and the baseline.

[Blend ratio of resin in peak P1 region and resin in peak P2 region]
The mass ratio of the resin in the peak P1 region and the resin in the peak P2 region of the polystyrene-based resin (A) used in the present invention is excellent in the balance between the strength and workability of the foam sheet obtained. (Resin in the region of peak P2) / (Resin in the region of peak P1) = 30/70 to 70/30 is preferable, and 40/60 to 60/40 is more preferable. This ratio can be easily controlled by adjusting the ratio of the multi-branched macromonomer (a1), styrene monomer (a2), and methacrylic acid (a3) used, and the type and amount of chain transfer agent. It is.

[Slope of log-log graph]
In addition, the slope in the region of molecular weight 250,000 to 10 million in the logarithmic graph with the horizontal axis representing the molecular weight obtained from GPC-MALLS of the polystyrene resin (A) used in the present invention and the vertical axis representing the radius of inertia is It is an index representing the degree of branching of the resin. About this inclination, it is essential that it is 0.30-0.55 from the point which expresses intensity | strength and moldability in the outstanding balance. When this inclination is larger than 0.55, the physical properties are closer to those of the linear resin, and conversely when it is smaller than 0.30, the fluidity is lowered due to the increase in the molecular weight accompanying the increase in the degree of branching, and the polyphenylene ether resin (B ) May be hindered when mixed with, and may impair homogeneity when foaming.

[GPC-MALLS measurement]
The GPC-MALS measurement described above is performed under the conditions of Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, and flow rate of 1.0 ml / min. is there. The analysis of GPC-MALLS measurement was performed using Wyatt's analysis software ASTRA, and the weight-average molecular weight of the polystyrene resin was obtained. In addition, the molecular weight of the resin obtained from GPC-MALLS was plotted on the horizontal axis and the inertial radius was plotted on the vertical axis. The slope in the region of molecular weight 250,000 to 10 million in the log-log graph with the axis (the slope of the approximate straight line automatically calculated by the software based on the measured value of only the linear portion obtained in the molecular weight range) ).

[Melt Mass Flow Rate MFR]
As for the fluidity of the polystyrene resin (A), mold reproducibility and mold releasability, shortening of the molding cycle, appearance, heat resistance and oil resistance when mixed with the polyphenylene ether resin (B) described later are used. It is preferable that MFR (230 degreeC, 37N) is resin of 0.5-12.0g / 10min by the point which is excellent in balance, such as property.

[Polystyrene resin (A)]
The polystyrene resin used in the present invention is a styrene resin having a branched structure as described above. However, as a method for efficiently obtaining such a resin, the polystyrene resin has a plurality of branches and a plurality of polymerizable duplexes. Copolymerizing a monomer mixture (a) containing, as essential components, a hyperbranched macromonomer (a1) having a bond, a styrene monomer (a2), and methacrylic acid (a3). Is preferred. By copolymerizing such a monomer mixture (a), a multibranched copolymer which is a copolymer of the multibranched macromonomer (a1), the styrene monomer (a2) and methacrylic acid (a3) is obtained. A polymer (A1), a linear resin (A2) that is a copolymer of a styrene monomer (a2) and a methacrylic acid (a3) produced at the same time, a homopolymer of a styrene monomer (a2), Although it contains a homopolymer of methacrylic acid (a3), as the polystyrene resin (A) in the present invention, it is only necessary to have the above-mentioned weight average molecular weight and inclination. Can be used as it is. In addition, a multi-branched polystyrene resin commercially available from DIC Co., Ltd. and styrene-methacrylic acid copolymer (SMAA) are mixed to prepare a resin having the aforementioned weight average molecular weight and gradient in GPC-MALS. May be.

  Further, a linear resin (A2) which is a copolymer of a styrene monomer (a2) and a methacrylic acid (a3) produced in advance, a homopolymer of a styrene monomer (a2), and a single weight of methacrylic acid (a3) The coalescence may be mixed with a copolymer resin of a hyperbranched macromonomer (a1), a styrene monomer (a2), and methacrylic acid (a3).

  In the monomer mixture (a) which is a raw material of the polystyrene resin (A) used in the present invention, the mass ratio (a2) / (a3) of the styrene monomer (a2) to the methacrylic acid (a3) is 99. The range of 0.5 / 0.5 to 85/15 is preferable because the balance between heat resistance and moldability is further improved and oil resistance is also improved. In particular, (a2) / (a3) is more preferably in the range of 99/1 to 88/10.

[Multi-branched macromonomer (a1)]
The multi-branched macromonomer (a1) has a plurality of branches and a plurality of polymerizable double bonds, and a polystyrene resin (A) excellent in the above properties can be easily obtained. In particular, from the viewpoint of controlling gel weight generation by controlling the weight average molecular weight of the multi-branched resin contained in the aforementioned peak P2 to 10 million or less and ensuring fluidity, the multi-branched macromonomer (a1) The weight average molecular weight (Mw) is preferably 1,000 to 15,000, more preferably 2,000 to 8,000.

[GPC measurement]
The molecular weight of the hyperbranched macromonomer (a1) was measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using “HPLC8010” manufactured by Tosoh Corporation, column Shodex KF802 × 2 + KF803 + KF804, solvent THF, flow rate 1 Measurement was performed at a condition of 0.0 ml / min.

  The branched structure in the multi-branched macromonomer (a1) is not particularly limited, but all three bonds other than the electron-withdrawing group and the bond that is bonded to the electron-withdrawing group are bonded to the carbon atom. Those that are branched by secondary carbon atoms and those that form a branched structure by repeating structural units having an ether bond, an ester bond or an amide bond are preferred.

When the hyperbranched macromonomer (a1) forms a branched structure with the quaternary carbon, the electron withdrawing group content is 2.5 × 10 5 per g of the hyperbranched macromonomer (a1). it is preferably in the range of ^{-4 mmol~5.0} × ¹⁰ -1 mmol, more preferably in the range of ^{5.0 × 10 -4 mmol~5.0 × 10 -2} mmol.

  It is essential that the multi-branched macromonomer (a1) has two or more polymerizable double bonds per molecule. The content of the polymerizable double bond is preferably in the range of 0.1 to 5.5 mmol, and more preferably in the range of 0.5 to 3.5 mmol, per 1 g of the macromonomer (a1). When the amount is less than 0.1 mmol, it is difficult to obtain a high molecular weight multibranched copolymer (A1). When the amount exceeds 5.5 mmol, the molecular weight of the multibranched copolymer tends to increase excessively. is there. The polymerizable double bond is preferably present at the tip of the multi-branched macromonomer (a1).

  The multibranched macromonomer (a1) that can be used in the present invention includes a branched structure formed by repeating a structural unit having an ester bond, an ether bond or an amide bond, and two or more polymerizable groups in one molecule at the branch end. A multi-branched macromonomer (a1-i) having a double bond can be mentioned.

  In the multibranched macromonomer (a1-i-1) in which a structural unit having an ester bond is repeatedly formed to form a branched structure, the carbon atom adjacent to the carbonyl group of the ester bond forming the molecular chain is a quaternary carbon atom. A preferred embodiment is one in which a polymerizable double bond such as a vinyl group or an isopropenyl group is introduced into a multi-branched polyester polyol. Introducing a polymerizable double bond into a multi-branched polyester polyol can be carried out by an esterification reaction or an addition reaction.

  In the multi-branched polyester polyol, a substituent may be introduced into a part of the hydroxy group in advance by an ether bond or other bond, and a part of the hydroxy group may be oxidized or other reaction. It may be denatured. Further, in the hyperbranched polyester polyol, a part of the hydroxy group may be esterified in advance.

  Examples of the multi-branched macromonomer (a1-i-1) include a compound having one or more hydroxy groups, a carbon atom adjacent to the carboxy group being a quaternary carbon atom, and two or more hydroxy groups. It is obtained by reacting a monocarboxylic acid having a multi-branched polymer, and then reacting the hydroxyl group, which is a terminal group of the polymer, with an unsaturated acid such as acrylic acid or methacrylic acid or an acrylic compound containing an isocyanate group. Things. In addition, about the multibranched polymer which formed the branched structure by repeating the structural unit which has an ester bond, "Angew.Chem.Int.Ed.Engl.29" p138-177 (1990) by Mr. Tamalia etc. Have been described.

  Examples of the compound having at least one hydroxy group include a) aliphatic diol, alicyclic diol, or aromatic diol, b) triol, c) tetraol, d) sugar alcohols such as sorbitol and mannitol, e) anne Hydroenenea-heptitol or dipentaerythritol, f) α-alkyl glucoside such as α-methyl glycoside, g) monofunctional alcohol such as ethanol, hexanol, h) alkylene oxide having a weight average molecular weight of at most 8,000, or The hydroxy group containing polymer etc. which were produced | generated by making the derivative and the hydroxyl group in 1 or more types of compounds selected from any of said a) -g) react can be mentioned.

  Examples of the a) aliphatic diol, alicyclic diol and aromatic diol include, for example, 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, polytetrahydrofuran, dimethylolpropane, neopentylpropane, 2-propyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,3-butanediol, diethylene glycol, triethylene glycol , Polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol; cyclohexanedimethanol, 1,3-dioxane-5,5-dimethanol; 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol Etc. . Examples of the b) triol include trimethylolpropane, trimethylolethane, trimethylolbutane, glycerol, 1,2,5-hexanetriol, 1,3,5-trihydroxybenzene, and the like. Examples of c) tetraol include pentaerythritol, ditrimethylolpropane, diglycerol, and ditrimethylolethane.

  Examples of the monocarboxylic acid in which the carbon atom adjacent to the carboxyl group is a quaternary carbon atom and having two or more hydroxy groups include, for example, dimethylolpropionic acid, α, α-bis (hydroxymethyl) butyric acid, α , Α, α-tris (hydroxymethyl) acetic acid, α, α-bis (hydroxymethyl) valeric acid, α, α-bis (hydroxymethyl) propionic acid, and the like. By using the monocarboxylic acid, the ester decomposition reaction is suppressed and a multibranched polyester polyol can be formed.

  Further, it is preferable to use a catalyst when producing the multi-branched polyester polyol. Examples of the catalyst include organic tins such as dialkyltin oxide, halogenated dialkyltin, dialkyltin biscarboxylate, and stannoxane. Examples thereof include compounds, titanates such as tetrabutyl titanate, organic sulfonic acids such as Lewis acid and p-toluenesulfonic acid.

Examples of the hyperbranched macromonomer (a1-i-2) in which a structural unit having an ether bond is repeated to form a branched structure include, for example, one hydroxy group in a compound having one or more hydroxy groups or cyclic ether compounds. By reacting the cyclic ether compound having the above, a multi-branched polymer is obtained, and then an unsaturated acid such as acrylic acid or methacrylic acid, an isocyanate group-containing acrylic compound, 4-chloromethyl is added to the hydroxy group which is a terminal group of the polymer. Examples thereof include those obtained by reacting halogenated methylstyrene such as styrene. Further, as a method for producing the multi-branched polymer, a compound having one or more hydroxy groups, two or more hydroxy groups and a halogen atom, -OSO ₂ OCH ₃ or -OSO ₂ is based on Williamson's ether synthesis method. A method of reacting with a compound containing CH ₃ is also useful.

As the compound having one or more hydroxy groups, any of those mentioned above can be used, and as the cyclic ether compound having one or more hydroxy groups, for example, 3-ethyl-3- (hydroxymethyl) Examples include oxetane, 2,3-epoxy-1-propanol, 2,3-epoxy-1-butanol, and 3,4-epoxy-1-butanol. The compounds having one or more hydroxy groups used in the Williamson ether synthesis method may be those described above, but aromatic compounds having two or more hydroxy groups bonded to an aromatic ring are preferred. Examples of the compound include 1,3,5-trihydroxybenzene, 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol and the like. Examples of the compound containing two or more hydroxy groups and a halogen atom, —OSO ₂ OCH ₃ or —OSO ₂ CH ₃ include, for example, 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-propanediol, etc. Can be mentioned. In addition, when manufacturing the said multi-branched polymer, it is preferable to use a normal catalyst, and examples of the catalyst include BF3 diethyl ether, FSO ₃ H, ClSO ₃ H, HClO _{4 and the} like. it can.

  In addition, examples of the multi-branched macromonomer (a1-i-3) in which a structural unit having an amide bond is repeated to form a branched structure include those having an amide bond in a repeating structure via a nitrogen atom in the molecule. A typical example is the generation 2.0 (PAMAM dentrimer) manufactured by Dentorite.

[Styrene monomer (a2)]
Examples of the styrene monomer (a2) that can be used in the present invention include the following. Styrene and its derivatives; for example, styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, alkyl styrene such as octyl styrene, fluorostyrene, chlorostyrene , Halogenated styrene such as bromostyrene, dibromostyrene and iodostyrene, nitrostyrene, acetylstyrene, methoxystyrene and the like.

  In the present invention, in addition to the hyperbranched macromonomer (a1), the styrenic monomer (a2), and methacrylic acid (a3), a monomer that can be copolymerized within a range that does not impair the heat resistance and workability of the resin composition. May be used. Examples of copolymerizable monomers that can be used in the present invention include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, heptyl acrylate, and octyl acrylate. , Alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, polymerizable unsaturated fatty acids such as acrylic acid, maleic acid, fumaric acid and itaconic acid, vinylcyan compounds, unsaturated carboxylic acid anhydrides, and amino groups An unsaturated compound etc. are mentioned, You may use 2 or more types of these simultaneously. Among these, it is preferable to use an alkyl acrylate ester from the viewpoint of easy control of the polymerization reaction with the styrene-based monomer (a2) and the point that it can be easily obtained industrially, and a foam of the resulting polystyrene-based resin composition It is more preferable to use butyl acrylate from the viewpoint of secondary workability.

  In the present invention, in addition to the hyperbranched macromonomer (a1), the styrenic monomer (a2), and methacrylic acid (a3), a rubbery polymer is used as long as the heat resistance and workability of the resin composition are not impaired. It may be used. Examples of the rubbery polymer that can be used in the present invention include polybutadiene, styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, and methyl methacrylate-butadiene. -A styrene copolymer etc. are mentioned, You may use these 2 or more types simultaneously. Among these, polybutadiene, styrene-butadiene copolymer, and styrene-butadiene are preferable from the viewpoint of easy control of the polymerization reaction with the styrene monomer (a2) and improvement in brittleness of the foam of the resulting styrene resin composition. -It is preferable to use a styrene copolymer.

[Polymerization method of hyperbranched macromonomer (a1), styrene monomer (a2) and methacrylic acid (a3)]
By copolymerizing the multi-branched macromonomer (a1), the styrene monomer (a2), methacrylic acid (a3), and a monomer mixture (a) composed of other monomers used in combination as necessary, A polystyrene resin (A), which is a mixture of a multi-branched resin, a linear resin and a low-branched resin that are simultaneously generated depending on polymerization conditions, is obtained. At this time, the above-mentioned multibranched macromonomer (a1) is preferably 50 ppm to 1% by mass with respect to the total mass of monomers other than the multibranched macromonomer (a1) in the monomer mixture (a). More preferably, by using a ratio of 100 ppm to 3000 ppm (mass basis), it is easy to produce a multi-branched resin, and the production of the polystyrene-based resin used in the present invention is facilitated.

  Various commonly used polymerization methods of styrene monomers can be applied to the polymerization reaction. The polymerization method is not particularly limited, but bulk polymerization, suspension polymerization, or solution polymerization is preferable. Among them, continuous bulk polymerization is particularly preferable from the viewpoint of production efficiency.For example, by performing continuous bulk polymerization incorporating one or more stirred reactors and a tubular reactor in which a plurality of mixing elements having no moving parts are fixed. An excellent resin can be obtained. Although thermal polymerization can be performed without using a polymerization initiator, it is preferable to use various radical polymerization initiators. Moreover, what is used for manufacture of a normal polystyrene can be used for polymerization adjuvants, such as a suspending agent and an emulsifier required for superposition | polymerization.

  In order to reduce the viscosity of the reaction product in the polymerization reaction, an organic solvent may be added to the reaction system. Examples of the organic solvent include toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, and anisole. , Cyanobenzene, dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone and the like. In particular, when it is desired to increase the amount of the hyperbranched macromonomer, it is preferable to use an organic solvent from the viewpoint of suppressing gelation. Thereby, the addition amount of the multi-branched macromonomer (a1) shown above can be dramatically increased to introduce a lot of branched structures, and gelation hardly occurs.

  The radical polymerization initiator is not particularly limited. For example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2-bis (4 , 4-di-butylperoxycyclohexyl) propane and other peroxyketals, cumene hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, di Dialkyl peroxides such as -t-hexyl peroxide, diacyl peroxides such as benzoyl peroxide and disinamoyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, t-butyl peroxide Pao such as oxyisylpropyl monocarbonate Siesters, N, N′-azobisisobutylnitrile, 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, and these can be used alone or in combination.

  Furthermore, you may add a chain transfer agent so that the molecular weight of the resin obtained may not become too large. As the chain transfer agent, either a monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer groups can be used. Examples of the monofunctional chain transfer agent include alkyl mercaptans and thioglycolic acid esters. Polyfunctional chain transfer agents include ethylene glycol, neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol and the like, the hydroxy group in thioglycolic acid or 3-mercaptopropionic acid And the like esterified with.

  In addition, long chain alcohols, polyoxyethylene alkyl ethers, polyoxyethylene lauryl ethers, polyoxyoleyl ethers, polyoxyethylene alkenyl ethers, and the like can be used to suppress gel formation of the resulting resin.

<Polymerization process>
In the polymerization step, a monomer mixture (a) using a hyperbranched macromonomer (a1), a styrene monomer (a2), methacrylic acid (a3) as a monomer component, or other monomers as required. By copolymerizing, a polystyrene resin (A) containing a multi-branched copolymer which is a copolymer of these three components can be obtained. An example of the reaction vessel of the polymerization apparatus for obtaining the resin (A) in the present invention is shown in FIG. That is, the reaction solution is sent to the stirring reactor (I) by the pump (1), then sent to the circulation polymerization line (II) by the pump (2), and the inside of the circulation polymerization line (II) is sent by the pump (3). It circulates, and after circulation, it is sent to the non-circulation polymerization line (III). Here, the circulation polymerization line (II) is composed of three reactors composed of (4) to (6), and the non-circulation polymerization line (III) is composed of three reactors composed of (7) to (9). Is done.

  If necessary, add monomers and solvents between the stirred reactor (I) and the circulation polymerization line (II), or between the circulation polymerization line (II) and the non-circulation polymerization line (III). It is also possible to add.

<Devolatile process>
After the polymerization step, a devolatilization tank 1 and a devolatilization tank 2 for volatilizing unreacted monomers and solvent components are connected. It is preferable to adjust the devolatilization tank 1 and the devolatilization tank 2 to 4.0 kPa and 1.3 kPa under reduced pressure, respectively, and after passing through the devolatilization tank 1 and the devolatilization tank 2, they are pelletized. The used polystyrene resin (A) can be obtained.

[Polyphenylene ether resin (B)]
The polyphenylene ether resin (hereinafter abbreviated as PPE resin) (B) used in the present invention is a homopolymer or copolymer composed of repeating units represented by the following general formula (1). Or a mixture of two or more resins having different substituents.

［式（１）中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４はそれぞれ独立して、水素原子、ハロゲン原子、置換基を有していても良いアルキル基、アルコキシ基又は置換基を有していても良いアリール基であり、ｎは繰り返し数である。］

[In Formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently have a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a substituent which may have a substituent. And n is the number of repetitions. ]

  Examples of the homopolymer represented by the general formula (1) include poly (2,6-dimethyl-1,4-phenylene) ether and poly (2-methyl-6-ethyl-1,4-phenylene). Ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-1,4-phenylene) ether, poly (2,6-di-n-propyl-) 1,4-phenylene) ether, poly (2-methyl-6-n-butyl-1,4-phenylene) ether, poly (2-ethyl-6-isopropyl-1,4-phenylene) ether, poly (2- Methyl-6-chloroethyl-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1,4-phenylene) ether, poly (2,6-dichloro-1,4-phenylene) ether Etc. The.

  Examples of the copolymer include a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, a copolymer of 2,6-dimethylphenol and o-cresol, -A copolymer of dimethylphenol and 2,3,6-trimethylphenol and the like.

  Among these, particularly preferred PPE resins (B) include poly (2,6-dimethyl-1,4-phenylene) ether, a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, Or a mixture of these.

  The method for producing the PPE resin (B) used in the present invention is not particularly limited, and can be obtained by various methods. For example, US Pat. Nos. 3,306,874 and 3,306,875, Examples thereof include the production methods described in JP-A-3257357, JP-A-3257358, JP-A-50-51197, JP-B-52-17880, JP-A-63-152628, and the like.

The PPE resin (B) used in the present invention may contain other various phenylene ether units as a partial structure as long as the effects of the present invention are not impaired. Examples of the phenylene ether unit include a 2- (dialkylaminomethyl) -6-methylphenylene ether unit and a 2- (N-alkyl-N-phenylaminomethyl) -6-methylphenylene ether unit. Further, a small amount of diphenoquinone or the like may be bonded to the main chain of the PPE resin. Furthermore, one of two carboxyl groups of maleic acid, fumaric acid, chloromaleic acid, cis-4-cyclohexene-1,2-dicarboxylic acid and acid anhydrides thereof, and these unsaturated dicarboxylic acids or General ones such as those in which two are esters, allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, epoxidized natural oil, allyl alcohol, 4-penten-1-ol, 1,4-pentadien-3-ol, etc. formula _C n _H 2n -3OH (n is a positive integer) of unsaturated alcohols of the general formula _{C n H 2n -5OH, C n} H 2n -7OH (n is a positive integer) are modified by an unsaturated alcohol such as PPE resin may be used. These modified PPE resins may be used alone or in combination of two or more.

  The molecular weight (number average molecular weight determined by gel permeation chromatography) of the PPE resin (B) used in the present invention is usually 1,000 to 100,000, preferably 6,000 to 60,000. The reduced viscosity (measured with 0.5 g / dl chloroform solution, 30 ° C., Ubbelohde type viscosity tube) of the PPE resin (B) is usually in the range of 0.35 dl / g to 0.65 dl / g, preferably Is in the range of 0.40 dl / g to 0.60 dl / g. In the present invention, even a blend of two or more PPE resins (B) having different reduced viscosities can be used.

  The styrenic resin composition of the present invention only needs to be a mixture of the above-mentioned polystyrene resin (A), PPE resin (B) and foaming agent (C), and the mixing ratio is obtained as desired processability. It is appropriately selected depending on the physical properties according to the application field of the molded body. Since the polystyrene resin (A) used in the present application has high fluidity when melted when compared with a general polystyrene resin having the same molecular weight, PPE resin is used as an improvement in heat resistance of the polystyrene resin (A). In the case of adding (B), the blending ratio can be increased from the conventional use ratio. For this reason, heat resistance as well as mechanical strength can be imparted without significantly impairing the molding processability of the polystyrene resin (A), and the problem of odor derived from the PPE resin (B) can be reduced. Furthermore, it is possible to develop an effect that is also excellent in oil resistance.

  The mixing ratio of the polystyrene resin (A) and the PPE resin (B) in the present invention is preferably 60 to 97 parts by mass of the polystyrene resin (A) and 3 to 40 parts by mass of the PPE resin (B). Preferably, they are 70-90 mass parts of polystyrene-type resin (A), and 10-30 mass parts of PPE resin (B).

[Foaming agent (C)]
As a foaming agent (C) in this invention, the foam of the styrene resin composition of this invention should just be manufactured.

  Specifically, carbon dioxide, propane, butane, pentane, pentene, hexene, methyl chloride, monochlorodifluoromethane, monochlorotrifluoromethane, monochlorodifluoroethane, monochloropentafluoroethane, dichlorodifluoromethane, dichlorotetrafluoroethane, trichloromonofluoromethane , Trichlorotrifluoroethane, tetrafluoroethane, sodium bicarbonate, ammonium bicarbonate, N, N'-dinitroso-pentamethylene-tetramine, N, N'-dimethyl-N, N'-nitroso-terephthalamide, azodicarbonamide , Azobisisobutyronitrile, benzene-sulfonyl-hydrazide-p, p'-oxybis (benzenesulfonyl-hydrazide), toluene-sulfonyl-hydrazide derivatives p- toluenesulfonic - sulfonyl - semicarbazide, Torihidorajino - triazine, zinc - amine complex compound, and the like. These may be used alone or in combination of two or more.

  The blending ratio of these foaming agents (C) is preferably 0.5 to 20 parts by mass when the total of the PPE resin (B) and the polystyrene resin (A) in the present invention is 100 parts by mass. Is 1 to 10 parts by mass.

  Moreover, the bubble nucleation agent normally used can be used for the styrene resin composition of this invention as needed. Examples of the bubble nucleating agent include inorganic fine powders such as talc, silicon oxide and titanium oxide, and organic fine powders such as zinc stearate and calcium stearate.

  In the present invention, the above polystyrene resin (A) and PPE resin (B) are used, but other styrene resins and various additives may be used in combination as required.

  Examples of the other styrenic resins include styrene homopolymers. The styrene homopolymer may be linear or multi-branched, and the shape is not particularly limited, and resin pellets, pulverized foam sheets, and the like are preferably used.

  As other styrene resins, rubber-modified styrene resins can be used for the purpose of reinforcing the strength. Examples of the rubber-modified styrenic resin include impact-resistant polystyrene, which can be produced by polymerizing a styrene monomer in the presence of a rubbery polymer. As these use ratios, from the viewpoint of the balance between the heat resistance and strength intended for the foam sheet, 0.1 to 20 mass with respect to the total amount of the polystyrene resin (A) and the PPE resin (B). % Is preferably used.

  For the purpose of reinforcing the strength, a copolymer of a styrene monomer and a (meth) acrylic ester may be used in combination. Although it does not specifically limit about content of (meth) acrylic ester, From a viewpoint of the balance of the heat resistance and the intensity | strength aimed at the foamed sheet, it is the total amount of the said polystyrene-type resin (A) and PPE resin (B). On the other hand, it is preferably used in the range of 0.1 to 10% by mass.

  Furthermore, as another styrene resin, a styrene thermoplastic elastomer can be used for the purpose of reinforcing the strength. Specific examples of the styrenic thermoplastic elastomer include a styrene-butadiene copolymer and a hydrogenated product thereof, a styrene-isoprene copolymer and a hydrogenated product thereof, and a methyl methacrylate-butadiene-styrene copolymer. The diene component content of these elastomers is not particularly limited, but a diene component content of 20% by mass or more with respect to all monomer components constituting the elastomer is preferable from the viewpoint of strength improvement effect. As these use ratios, from the viewpoint of the balance between the heat resistance and strength intended for the foam sheet, 0.1 to 5 mass with respect to the total amount of the polystyrene resin (A) and the PPE resin (B). % Is preferably used.

  Examples of various additives include stabilizers, odor inhibitors, and flame retardants.

  Examples of the stabilizer include antioxidants, heat stabilizers, light stabilizers, and the like. Specifically, phenolic oxidation such as octadecyl-3- (3,5-t-butyl-4-hydroxyphenyl) propionate. Inhibitors, sulfur-based antioxidants such as 3,3-thiobispropionic acid dioctadecyl ester, phosphorus-based heat stabilizers such as triphenyl phosphite, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, etc. Amine heat stabilizers, hindered amine light stabilizers, and the like.

  The blending ratio of the stabilizer is 0.01 parts by mass to 5 parts by mass when the total of the polystyrene-based resin (A) and the PPE resin (B) in the present invention is 100 parts by mass, preferably 0.8. 05 parts by mass to 1 part by mass.

  Examples of the odor inhibitor include zeolite, silica, activated alumina and the like. The blending ratio of the odor inhibitor (E) is 0.05 to 10 parts by mass, when the total of the polystyrene resin (A) and the PPE resin (B) in the present invention is 100 parts by mass, preferably Is 0.1 to 5 parts by mass. In the composition of the present invention, as described above, since the generation of odor is suppressed as compared with the usual polystyrene / PPE alloy, it is possible to reduce the use ratio of the odor inhibitor.

  The styrene-based resin composition of the present invention does not greatly impair the flame retardancy of the PPE resin (B), but a flame retardant is blended in order to impart a higher level of flame retardancy to the foam. May be.

  The type of the flame retardant is not particularly limited, and a specific flame retardant conventionally used for a resin composition of a PPE resin and a polystyrene-based resin or provided in JP 2008-0379970 A or the like is used. Can be used.

  Examples of the flame retardant include a red phosphorus type such as red phosphorus; triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, norosinol-bis- (diphenyl phosphate), 2-Ethylhexyl diphenyl phosphate, phosphate ester such as dimethylmethyl phosphate, triallyl phosphate; halogen-containing phosphate ester such as trichloroethyl phosphate, trisdichloropropyl phosphate, tris-β-chloropropyl phosphate; aromatic condensed phosphorus Examples thereof include condensed phosphates such as acid esters and halogen-containing condensed phosphates; and polyphosphates such as ammonium polyphosphate and polychlorophosphite.

  Of these, from the viewpoint of avoiding the generation of harmful gases during combustion, those not containing halogen are preferable, and in this respect, red phosphorus-based ones are preferably used. In addition, red phosphorus can be used even if it is coated with a phenolic resin or contains magnesium hydroxide or titanium oxide.

  In addition, as the flame retardant, inorganic flame retardants such as aluminum hydroxide, antimony trioxide, antimony pentoxide, and magnesium hydroxide can also be used.

  The proportion of the flame retardant used can be appropriately selected according to the required level of flame retardancy of the obtained molded product, but the polystyrene resin (A) used in the present invention as described above has the same degree. Compared with general-purpose polystyrene having fluidity, it has a high molecular weight, so that the flame retardancy of the PPE resin (B) is not significantly impaired, and the use ratio can be lowered. Therefore, it is also possible to reduce the contamination of the mold due to the bleed-out of the flame retardant.

  Generally, the amount of the flame retardant used is usually 0.5 to 30 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the resin components.

[Other additives]
As long as the object of the present invention is not impaired, the styrenic resin composition of the present invention includes auxiliary agents such as stearic acid, sodium stearate, barium stearate, magnesium stearate, liquid paraffin, olefin wax, and stearylamide compound. Can also be used together. Moreover, you may mix | blend various additives as needed. Examples of such additives include UV absorbers, antistatic agents, lubricants, antiblocking agents, pigments, dyes, crosslinking agents, crosslinking aids, plasticizers, phosphate ester compounds and wollastonite, calcium silicate, Examples include inorganic substances such as kaolin, mica, clay, zinc oxide, barium sulfate, and calcium carbonate.

[Method for producing foam]
There is no restriction | limiting in particular in the manufacturing method of the molded object which consists of a styrene-type resin composition of this invention, The above-mentioned various additives added by a polystyrene-type resin (A), PPE resin (B), and if needed are heat-melted. The composition containing a foaming agent (C) and then extruding and foaming, a polystyrene resin (A), a PPE resin (B), a foaming agent (C), and an additive added as necessary A method of heating and melting and press-molding a product, followed by foaming by reheating, a granular resin containing a polystyrene resin (A), a PPE resin (B), a foaming agent (C), and an additive added as necessary Examples thereof include a method of filling the composition in a mold and heating to foam. Among these, the method of injecting the foaming agent (C) and extruding and foaming after the polystyrene-based resin (A), the PPE resin (B), and various additives added as necessary are heated and melted are homogeneous. It is preferable at the point which can obtain a foam.

  When molding a foamed sheet, this resin composition is supplied to an extruder, heated and melted and kneaded, then extruded from a circular die, T-die, etc., and applied with a normal foam molding method by foaming. Can do.

  Furthermore, an inorganic compound can be used as a nucleating agent in order to control the amount and size of the foamed cells. A preferable inorganic compound is talc.

  Also, the mixing order of the resins is not particularly limited. For example, a method of adding a foaming agent (C) to a polystyrene resin (A) and / or a PPE resin (B) and using it in a melt kneader, or a polystyrene resin in advance. After preparing a master batch in which a foaming agent is kneaded at a high concentration in a part of (A) and / or PPE resin (B), this master batch and the remaining polystyrene resin (A) and PPE resin (B) are kneaded. Thereafter, a foam molding method and the like can be mentioned.

  In addition, if necessary, after preparing a master batch in which other additives are melt-kneaded at the same time, polystyrene resin (A), PPE resin (B) and other resins and additives are prepared in advance, You may use the method of melt-kneading this masterbatch, a styrene resin (A), PPE resin (B), and a foaming agent (C), and foam-molding.

  Further, the extrusion temperature at the time of melt kneading is preferably in the range of 170 to 300 ° C., and the die temperature of the circular die, T die, etc. is in the range of 120 to 170 ° C. for performing stable foam molding. It is preferable.

  Although the magnification at the time of manufacturing a foam sheet is not specifically limited, It is preferable that it is 5-50 times from a viewpoint of maintenance of mechanical strength, the weight reduction by foaming, and the balance of a moldability.

  The foamed sheet obtained above can be subjected to secondary processing by thermoforming to form a molded body. As the thermoforming method, a hot plate contact heat forming method, a vacuum forming method, a vacuum / pressure forming method, a plug assist forming method, or the like is preferably used.

  The shape of the molded body is not particularly limited, such as various packs and cases, but is for food packaging from the viewpoint of moldability, heat resistance, low odor, and oil resistance, which are the characteristics of the foamed sheet of the present invention and the molded body. The use as a container tray or a container is particularly preferable.

  It is also possible to bond a film to the front and back of the obtained foamed sheet or a molded product obtained by secondary molding for the purpose of imparting improved mechanical strength and chemical resistance. Specifically, it is also possible to thermally laminate a polystyrene-based inflation film or to bond an olefin-based film (CPP) using an adhesive.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention should not be limited to the scope of these examples. Hereinafter, “part” and “%” are based on mass unless otherwise specified.

[GPC-MALLS measurement]
GPC-MALS measurement of polystyrene resin was performed under the conditions of Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, and flow rate of 1.0 ml / min. In addition, the analysis of the measurement of GPC-MALLS was performed by analysis software ASTRA manufactured by Wyatt, and the weight average molecular weight was obtained for the styrene resin composition, and the molecular weight of the resin composition obtained from GPC-MALLS was plotted on the horizontal axis. The slope in the region of molecular weight 250,000 to 10 million in the logarithmic graph with the radius of inertia as the vertical axis (automatically calculated by the software based on the measured value of only the linear portion obtained in the molecular weight range) The slope of the approximate line was determined.

[NMR measurement method]
Nuclear magnetic resonance spectroscopy ⁽¹ H-NMR, JEOL Ltd. JNM-LA300 type) was used.

[Melt Mass Flow Rate Measurement Method]
The measurement was performed according to JIS K7210. The measurement conditions are 230 ° C. and 37N.

[Method for producing foam sheet]
A polystyrene resin (A) and a PPE resin (B) were dry blended in advance, melt-kneaded at 250 to 300 ° C. using a 30 mmφ twin screw extruder, water-cooled, and strand-cut to obtain pellets. The pelletized sample is supplied to a tandem foam extrusion apparatus, melted at 210 to 300 ° C. in the first extruder, injected with a foaming agent (C), and then introduced into the second extruder and 180 to 240 ° C. The foamed sheet was obtained by discharging from the die while cooling.

[Secondary molding of foam]
The obtained foamed sheet was vacuum-formed at a heater temperature of 300 to 350 ° C. using four types of cup molds having an opening diameter of 80 mm and different drawing ratios (0.2 to 0.8). The next processed product was obtained.

[Formability evaluation of foam sheet]
The following evaluation was performed about the obtained secondary molded article.
A: The shape of the container is completely reproduced.
○: Some types are not reproduced,
Δ: A small hole is generated at the edge of the bottom of the container.
×: A large hole occurs at the bottom of the container

[Evaluation of heat resistance of foam sheet]
The secondary molded product of the foamed sheet was placed in an oven maintained at 110 ° C. for 10 minutes, and then the appearance of the container was visually evaluated in the following four stages.
A: No change
○: There is no problem in practical use although some surface burns are observed,
Δ: The container is slightly deformed,
×: Container is greatly deformed

[Strength evaluation of molded body]
A top-and-bottom compression test of the secondary molded product of the foam sheet was performed.
A: No problem,
○: Level that does not cause any practical problems
Δ: Difficult,
×: Easily breaks

[Oil resistance evaluation]
The oil resistance was evaluated using a non-foamed sheet. A non-foamed sheet having a thickness of 0.3 mm, obtained at 210 to 300 ° C. using a 30 mmφ extruder, was wrapped around a paper tube having a diameter of 90 mm, coated with salad oil, and the occurrence of cracks after 30 minutes was confirmed.
A: No problem,
○: Level that does not cause any practical problems
Δ: Crack generation,
×: Break

  As PPE resin (B), poly (2,6-dimethyl-1,4-phenyl ether) (B-1) having a reduced viscosity of 0.53 dl / g at 30 ° C. in 0.5 g / 100 ml chloroform is used. did.

  As the blowing agent (C), a 70/30 (mass%) mixture (C-1) of n-butane and isobutane was used.

Reference Example 1 Synthesis of Multibranched Macromonomer (Mm-1) <Synthesis of Multibranched Polyether Polyol 1>
To a 2 liter flask equipped with a stirrer, a thermometer, a dropping funnel and a 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 Multibranched Polyether 1 Having Methacryloyl Group and 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 while introducing 7% oxygen-containing nitrogen (v / v) under reduced pressure, and 60 g of a multibranched polyether having an isopropenyl group and an acetyl group was obtained. Obtained. The weight average molecular weight of the obtained multibranched polyether was 3,900, and the introduction ratios of isopropenyl group and acetyl group into the multibranched polyether polyol were 30 mol% and 62 mol%, respectively.

Reference Example 2 Synthesis of Multibranched Macromonomer (Mm-2) <Synthesis of Multibranched Polyether Polyol 2>
In a 1000 mL three-necked flask connected with nitrogen, air reflux condenser, magnetic stir bar and thermometer, 1.24 g (8.7 mmol) of boron trifluoride diethyl ether complex was dried and the peroxide was removed. Dilute with 273 g of methyl-t-butyl ether. In a separate container, 140 g (1.21 mol) of 3-hydroxymethyl-3-ethyloxetane and 70.0 g (1.21 mol) of propylene oxide were mixed, and the above three-necked flask was consumed with a metering pump for 5.5 hours. And dripped. At this time, the system was cooled by an ice bath as needed to keep the temperature in the system at 20 ° C. After completion of the dropwise addition, 63.0 g (1.08 mol) of propylene oxide was further added dropwise over 3 hours while keeping the temperature in the system at 20 ° C., and the mixture was further stirred for 4 hours. Here, 0.620 g (4.4 mmol) of boron trifluoride diethyl ether complex was added, and the mixture was further stirred at 20 ° C. for 6 hours. The reaction mixture was adsorbed and removed by adding hydrotalcite 10 times the weight of boron trifluoride diethyl ether complex used in the reaction and refluxing for 1 hour. After the hydrotalcite was filtered off, methyl-t-butyl ether was removed to obtain 267 g of a transparent and highly viscous multi-branched polyether polyol. This multi-branched polyether polyol has Mn = 2,876, Mw = 7,171, hydroxyl value = 253 mg · KOH / g, and 3-hydroxymethyl-3-ethyloxetane: propylene oxide on a molar basis from proton NMR = 1: 1.9.

<Synthesis of multi-branched polyether 2 having acryloyl group>
In a 500 mL four-necked flask equipped with a Dean-Stark tube, nitrogen and air introduction tube, a stirrer, and a thermometer, the multi-branched polyether polyol obtained in the above <Synthesis of multi-branched polyether polyol 2> 155 g, 51 g of acrylic acid, 200 g of cyclohexane, 0.21 g of hydroquinone monomethyl ether, and 4 g (12.3 mmol) of dodecylbenzenesulfonic acid as a catalyst were added, and the temperature was raised to 82 ° C. under a mixed gas flow of nitrogen and air 2 to 1. . Cyclohexane reflux began, and water flow began gradually. Thereafter, when the temperature was raised to 85 ° C. and reacted for 18 hours, 60% of the theoretical dehydration amount was reached, so cooling was started. After cooling to around 30 ° C., 5% sodium hydroxide aqueous solution and 15% NaCl aqueous solution were added for washing. The hydroxyl group value of the obtained polymerizable unsaturated group-containing multi-branched polyether was 70 mg · KOH / g, and the acrylic group introduction rate of all hydroxyl groups was 60%.

Reference Example 3 Synthesis of Multibranched Macromonomer (Mm-3) <Synthesis of Multibranched Polyether 1 Having Styryl Group and 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 multi-branched polyether having a styryl group and an acetyl group. The obtained multi-branched polyether had a mass average molecular weight of 4,800, and the styryl group and acetyl group introduction rates into the multi-branched polyether polyol were 38 mol% and 57 mol%, respectively.

Reference Example 4 Synthesis of Multibranched Macromonomer (Mm-4) <Synthesis of Multibranched Macromonomer Having Methacryloyl Group and 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 (Mm-3) having an isopropenyl group and an acetyl group. It was. The resulting multi-branched macromonomer (Mm-3) has a weight average molecular weight of 3,000, a number average molecular weight of 2,100, and a double bond introduction amount of 2.00 mmol / g, an isopropenyl group and an acetyl group. The introduction rates were 55 mol% and 36 mol%, respectively.

Reference Example 5 Synthesis of hyperbranched macromonomer (Mm-5) <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 styryl group content of the dendrimer was 2.7 mmol / gram.

Reference Example 6 Synthesis of Multibranched Macromonomer (Mm-6) <Multibranched Polyether Polyol 2 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 obtained mixture was dissolved in dichloromethane and washed three times with water, and then the dichloromethane solution was added dropwise to hexane to precipitate a multibranched polyether. This was filtered and dried to obtain 12 g of a multi-branched polyether polyol having a styryl group and an acetyl group. The mass average molecular weight was 3,200, and the styryl group content was 3.5 mmol / gram.

(Reference Example 7) Synthesis of hyperbranched macromonomer (Mm-7) <Synthesis of hyperbranched polyester polyol having methacryloyl group and acetyl group>
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 “Borton H20”, 1.25 g of dibutyltin oxide, and 100 g of methyl methacrylate having an isopropenyl group as a functional 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 6 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 12 g of a hyperbranched polyester having an isopropenyl group and an acetyl group. The obtained multibranched polyester had a mass average molecular weight of 2860 and a number average molecular weight of 3770, and the introduction rate of isopropenyl group and acetyl group into the multibranched polyester polyol was 55% and 40%, respectively.

Example 1
Prepare a mixed solution consisting of 98 parts of styrene monomer, 2 parts of methacrylic acid, 1000 ppm of the multi-branched macromonomer (Mm-1) obtained in Reference Example 1 and 8 parts of toluene with respect to the total amount of styrene monomer and methacrylic acid. Furthermore, 150 ppm of t-butyl peroxybenzoate as an organic peroxide was added to the total amount of styrene monomer and methacrylic acid, and continuous bulk polymerization was performed under the following conditions using the apparatus shown in FIG. The stirring reactor (I) was 110 to 130 ° C., and the circulation polymerization line (II) and the non-circulation polymerization line (III) were 115 to 170 ° C., respectively. From the reaction solution, unreacted monomers and solvent components are recovered in the devolatilization tank 1 and the devolatilization tank 2 installed after the non-recycling polymerization line (III) as the final reactor. The devolatilization tank 1 and the devolatilization tank 2 were set to 240 to 280 ° C. Thereafter, it passed through a single tube and was converted into a strand and pelletized with a pelletizer to obtain a polystyrene resin (A-1).

  80 parts of the obtained polystyrene-based resin (A-1) and 20 parts of PPE resin (B-1) were supplied to a tandem foaming extrusion apparatus, butane gas was injected and the die temperature was 160 ° C., and the thickness was 2.0 mm. A foam sheet was produced. The obtained foamed sheet was vacuum-formed, and the secondary formability, heat resistance and strength were evaluated. Further, the same composition was supplied to a 30 mmφ extruder to produce a non-foamed sheet having a thickness of 0.3 mm, and the oil resistance was evaluated.

Example 2
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-2 obtained in Reference Example 2 to obtain a styrene resin (A-2).

Example 3
Except that the hyperbranched macromonomer was changed to Mm-3 obtained in Reference Example 3 to obtain a styrene resin (A-3), all were the same as Example 1.

Example 4
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-4 obtained in Reference Example 4 to obtain a styrene resin (A-4).

Example 5
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-5 obtained in Reference Example 5 to obtain a styrene resin (A-5).

Example 6
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-6 obtained in Reference Example 6 to obtain a styrene resin (A-6).

Example 7
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-7 obtained in Reference Example 7 to obtain a styrene resin (A-7).

Example 8
Example 7 was the same as Example 7 except that the hyperbranched macromonomer was changed to 200 ppm to obtain a styrene resin (A-8).

Example 9
Example 7 was the same as Example 7 except that the hyperbranched macromonomer was set to 2000 ppm to obtain a styrene resin (A-9).

Example 10
Example 8 was the same as Example 8, except that 92 parts of styrene monomer and 8 parts of methacrylic acid monomer were used to obtain a styrene resin (A-10).

Example 11
All were the same as Example 10 except that the hyperbranched macromonomer was 1000 ppm to obtain a styrene resin (A-11).

Example 12
All were the same as Example 10 except that the hyperbranched macromonomer was 2000 ppm and a styrene resin (A-12) was obtained.

Example 13
Example 11 was the same as Example 11 except that 90 parts of polystyrene resin (A-1) and 10 parts of PPE resin (B-1) were used.

Example 14
Example 11 was the same as Example 11 except that 70 parts of polystyrene resin (A-1) and 30 parts of PPE resin (B-1) were used.

Comparative Example 1
All were the same as Example 1 except 100 parts of styrene monomer, 0 parts of methacrylic acid monomer, and 0 ppm of multibranched macromonomer.

Comparative Example 2
Example 1 was the same as Example 1 except that 98 parts of styrene monomer and 2 parts of methacrylic acid monomer were used and that the multibranched macromonomer was 0 ppm.

Comparative Example 3
Example 1 was the same as Example 1 except that 92 parts of styrene monomer and 8 parts of methacrylic acid monomer were used and that the multibranched macromonomer was 0 ppm.

  The evaluation result about Examples 1-14 and Comparative Examples 1-3 is described in Tables 1-3.

Example 6 (Reference Example)
The same procedure as in Example 1 was conducted except that the hyperbranched macromonomer was changed to Mm-6 obtained in Reference Example 6 to obtain a styrene resin (A-6).

Example 8 (Reference Example)
Example 7 was the same as Example 7 except that the hyperbranched macromonomer was changed to 200 ppm to obtain a styrene resin (A-8).

Example 10 (Reference Example)
Example 8 was the same as Example 8, except that 92 parts of styrene monomer and 8 parts of methacrylic acid monomer were used to obtain a styrene resin (A-10).

Claims (10)

A resin composition containing a polystyrene resin (A), a polyphenylene ether resin (B), and a foaming agent (C), wherein the polystyrene resin (A) is
It is a multi-branched resin having a structure derived from styrene monomer (a2) and a structure derived from methacrylic acid (a3), and (1) the weight average molecular weight determined by GPC-MALS method is 150,000 to 700,000 ,
(2) In a log-log graph with the molecular weight determined by the GPC-MALS method as the horizontal axis and the inertial radius as the vertical axis, the slope in the region of the molecular weight of 250,000 to 10 million is 0.30 to 0.55. A featured styrene resin composition. The styrene resin composition according to claim 1, wherein a melt mass flow rate MFR (230 ° C, 37N) of the polystyrene resin (A) is 0.5 to 12.0 g / 10 min. The polystyrene resin (A) contains a multi-branched macromonomer (a1) having a plurality of branches and a plurality of polymerizable double bonds, a styrene monomer (a2), and methacrylic acid (a3). The styrenic resin composition according to claim 1 or 2, which is a copolymer obtained from the monomer mixture (a) to be produced. The mass ratio (a2) / (a3) of the styrene monomer (a2) and the methacrylic acid (a3) in the monomer mixture (a) is in the range of 99.5 / 0.5 to 85/15. The styrenic resin composition according to claim 3. The weight average molecular weight of the multibranched macromonomer (a1) is 1,000 to 15,000, and the total mass of monomers other than the multibranched macromonomer (a1) in the monomer mixture (a) The styrenic resin composition according to claim 3 or 4, wherein the hyperbranched macromonomer (a1) is in a proportion of 50 ppm to 1% by mass. The blending ratio of the polystyrene resin (A) and the polyphenylene ether resin (B) is 60 to 97 parts by mass of the polystyrene resin (A) and 3 to 40 parts by mass of the polyphenylene ether resin (B). Item 6. The styrenic resin composition according to any one of Items 1 to 5. A foamed sheet obtained by foaming the styrenic resin composition according to any one of claims 1 to 6. The foam sheet according to claim 7, wherein the foam sheet has a thickness of 0.5 to 5.0 mm and a bulk density of 0.02 to 0.20 g / cm ³ . A molded body obtained by secondary molding of the foamed sheet according to claim 7 or 8. The molded product according to claim 9, which is used for food packaging.

Images