Resin composition, molding, method for producing molding, and master batch

Abstract

To provide a syndiotactic polystyrene resin composition capable of achieving a molding excellent in toughness.SOLUTION: The resin composition is obtained by melt-kneading: a kneaded product (M) obtained by melt-kneading respective components including at least a rubber-like elastic body (M2) and one or more polystyrenes (M1) selected from a multi-branched polystyrene (M1-1), a polystyrene (M1-2) having a syndiotactic structure with a weight average molecular weight of 130,000 or more, and a polystyrene (M1-3) having an atactic structure with a weight average molecular weight of 210,000 or more; and a polystyrene (A) having a syndiotactic structure.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, a molded article, a method for producing the molded article, and a masterbatch.

Background Art

[0002] Polystyrene having a syndiotactic structure can achieve a high degree of crystallinity, and thus the sheet obtained therefrom is excellent in heat resistance and chemical resistance and is used as various molded articles such as containers. For example, Patent Document 1 discloses a film obtained using a resin composition mainly composed of syndiotactic polystyrene (hereinafter also referred to as "syndiotactic polystyrene-based resin composition").

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although syndiotactic polystyrene-based resin compositions are excellent in various properties, further improvements have been expected. An object of the present invention is to provide a syndiotactic polystyrene-based resin composition capable of realizing a molded article excellent in toughness.

Means for Solving the Problems

[0005] As a result of intensive studies by the present inventors, it has been found that a molded article excellent in toughness can be obtained by preparing a syndiotactic polystyrene-based resin composition after pre-kneading specific components, and the present invention has been completed. According to the present invention, the following resin compositions and the like are provided. 1. A kneaded product (M) obtained by melt-kneading components including at least one polystyrene (M1) selected from hyperbranched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure with a weight-average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure with a weight-average molecular weight of 210,000 or more, and a rubber-like elastomer (M2); Polystyrene (A) having a syndiotactic structure; A resin composition obtained by melt-kneading the above. 2. The resin composition according to 1, wherein the content of the rubber-like elastic material (M2) in the kneaded material (M) is 21 to 49 mass %. 3. The resin composition according to 1 or 2, wherein the styrene content of the rubber-like elastomer (M2) is 10 to 65% by mass. 4. The resin composition according to any one of 1 to 3, wherein the content of the rubber-like elastomer (M2) is 0.5 to 25% by mass. 5. The resin composition according to any one of 1 to 4, wherein the content of the polystyrene (M1) in the kneaded product (M) is 51 to 79 mass %. 6. The resin composition according to any one of 1 to 5, wherein the polystyrene (M1) comprises the hyperbranched polystyrene (M1-1). 7. The resin composition according to any one of 1 to 6, wherein the polystyrene (M1) comprises the hyperbranched polystyrene (M1-1) and the polystyrene (M1-3) having an atactic structure and a weight average molecular weight of 210,000 or more. 8. The resin composition according to any one of 1 to 7, wherein the blending amount of the kneaded material (M) is 1 to 50 mass %. 9. The resin composition according to any one of 1 to 8, wherein the content of the polystyrene (A) having a syndiotactic structure is more than 40% by mass and not more than 99% by mass. 10. The resin composition according to any one of 1 to 9, wherein the polyethylene content is less than 20% by mass. 11. The resin composition according to any one of 1 to 10, which is for melt molding. 12. The resin composition according to any one of 1 to 11, wherein the kneaded mixture (M) is a masterbatch. 13. A molded article obtained from the resin composition according to any one of 1 to 12. 14. A kneaded product (M) obtained by melt-kneading components including at least one polystyrene (M1) selected from hyperbranched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure with a weight-average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure with a weight-average molecular weight of 210,000 or more, and a rubber-like elastomer (M2); Polystyrene (A) having a syndiotactic structure; a step of melt-kneading the above to prepare a resin composition; and The resin composition is melt-molded. A method for manufacturing a molded body. 15. One or more polystyrenes (M1) selected from hyperbranched polystyrenes (M1-1), polystyrenes (M1-2) having a syndiotactic structure and a weight-average molecular weight of 130,000 or more, and polystyrenes (M1-3) having an atactic structure and a weight-average molecular weight of 210,000 or more; and A rubber-like elastic body (M2) is included. Masterbatch (M'). [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a syndiotactic polystyrene resin composition that can realize a molded article having excellent toughness. DETAILED DESCRIPTION OF THE INVENTION

[0007] The resin composition, molded article, method for producing the molded article, and masterbatch of the present invention will be described in detail below. In this specification, "x to y" represents a numerical range of "greater than or equal to x and less than or equal to y." The upper and lower limits of the numerical ranges can be combined in any manner. Furthermore, a combination of two or more of the individual embodiments of the present invention described below is also an embodiment of the present invention. Furthermore, a numerical range of "greater than x" implies "greater than x," and a numerical range of "less than or equal to y" implies "less than y."

[0008] [Resin composition] A resin composition according to one embodiment of the present invention is obtained by melt-kneading a kneaded product (M) obtained by melt-kneading components including a specific polystyrene (M1) and a rubber-like elastomer (M2), and a polystyrene (A) having a syndiotactic structure (hereinafter also simply referred to as "component (A)"). The polystyrene (M1) is one or more polystyrenes selected from hyperbranched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure and a weight-average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure and a weight-average molecular weight of 210,000 or more. Hereinafter, these are collectively referred to as "component (M1)."

[0009] The present inventors have focused on the order of mixing the components when preparing a syndiotactic polystyrene resin composition and have found that a molded article with higher toughness can be achieved by pre-mixing a rubber-like elastomer (M2: usually particulate) with a specific polystyrene resin (M1) and then mixing it with the matrix resin component (A). The present inventors have considered the mechanism of this effect as follows.

[0010] When all of the resin pellets that make up the resin composition are dry-blended, put into a hopper, and melt-kneaded in an extruder, the rubber-like elastomer (M2) is dispersed in a bare state, making it easily deformable from an early stage inside the extruder. Therefore, when extruded from a die, the rubber-like elastomer (M2) is stretched thinly in the extrusion direction (MD) together with the matrix resin. On the one hand, in the present invention, first, a specific polystyrene (M1) and a rubber-like elastomer (M2) are kneaded and extruded to obtain a kneaded product (M) in which the rubber-like elastomer (M2) is elongated in the extrusion direction in the polystyrene (M1). When such a kneaded product (M) is kneaded with a component (A) which is a matrix resin, the rubber-like elastomer (M2) is randomly arranged and dispersed in the component (A) in such a state as to be protected by the relatively deformation-resistant polystyrene (M1). Therefore, the deformation of the rubber-like elastomer (M2) is suppressed, and the randomness can be maintained up to the die outlet. As a result, in the molded body, the rubber-like elastomer (B) exists in a state where the width is wide also in the TD direction (the direction perpendicular to the extrusion direction), and stress concentration hardly occurs with respect to the tensile stress in the MD direction, and it is considered that a molded body having high toughness can be obtained.

[0011] As described above, the resin composition according to one aspect of the present invention has a structure different from that of a conventional syndiotactic polystyrene-based resin composition, but it is difficult to distinguish the structural difference by ordinary indices. In addition, using all kinds of equipment to specify the difference and conducting experiments and the like with an unrealistic number of times involve extremely excessive economic expenditures, and it is also difficult to comprehensively express the results in the claims. Therefore, it is almost impractical to directly specify the resin composition according to one aspect of the present invention by its structure or properties.

[0012] Hereinafter, each component of the resin composition according to one aspect of the present invention will be described.

[0013] <Kneaded product (M)> The kneaded product (M) is obtained by melt-kneading a specific polystyrene (M1) and a rubber-like elastomer (M2) and performing extrusion molding. The components are not limited to these, and other components described later may be included. The conditions for melt-kneading these components are not particularly limited, and ordinary methods can be adopted. For example, it is carried out under the conditions of 180 to 300°C. The kneaded product (M) may be in the form of pellets, for example. In this case, the kneaded product (M) can also be referred to as a masterbatch for dispersing the rubber-like elastomer (M2) in the component (A). A masterbatch is a resin composition (e.g., in pellet form) that contains a dispersion medium such as an additive to be dispersed in the final resin composition at a high concentration in a predetermined resin. By kneading the masterbatch and the matrix resin of the final resin composition, the dispersion medium can be effectively dispersed in the matrix resin.

[0014] <Masterbatch (M’)> The masterbatch (M’) according to one aspect of the present invention can also be expressed as follows. One or more polystyrenes (M1) selected from multi-branched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure with a weight average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure with a weight average molecular weight of 210,000 or more, and a rubber-like elastomer (M2), masterbatch (M’).

[0015] The conditions such as the components and composition of the masterbatch (M’) can be directly applied to the description of the kneaded product (M).

[0016] Since the masterbatch (M’) according to one aspect of the present invention can improve the toughness of a molded article obtained from a syndiotactic polystyrene-based resin composition having the following-described component (A) as a matrix, it can also be said to be for modifying the resin composition.

[0017] <Polystyrene (M1)> The polystyrene (M1) can be one or more of hyperbranched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure with a weight-average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure with a weight-average molecular weight of 210,000 or more. Hereinafter, these components will be referred to simply as "component (M1-1)," "component (M1-2)," and "component (M1-3)." These components have high viscosity and / or melting point, making them less likely to deform in an extruder. Using these components as resin components of the kneaded material (M) can exert the above-mentioned effects and improve the toughness of molded articles obtained from the resin composition. It can also improve the moldability of the resin composition.

[0018] (hyperbranched polystyrene (M1-1)) Examples of the hyperbranched polystyrene (M1-1) include polymers obtained by copolymerizing a macromonomer having multiple polymerizable double bonds with a styrene-based monomer.

[0019] Examples of the macromonomer include a multifunctional polyester (meth)acrylate having polymerizable double bonds at multiple molecular ends, a multifunctional polyether (meth)acrylate having polymerizable double bonds at multiple molecular ends, a multifunctional polyurethane (meth)acrylate having polymerizable double bonds at multiple molecular ends, and divinylbenzene.

[0020] Examples of styrene-based monomers include styrene and derivatives thereof, such as alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; and others such as nitrostyrene, acetylstyrene, and methoxystyrene. These may be used alone or in combination of two or more. The multi-branched polystyrene may have a syndiotactic, isotactic, or atactic structure.

[0021] In addition, as the component (M1-1), crosslinked polystyrene into which a crosslinked structure has been introduced by reaction extrusion using a peroxide, electron beam irradiation, or the like can also be used.

[0022] There is no particular limitation on the molecular weight of the component (M1-1), but the weight average molecular weight is, for example, 100,000 to 400,000, preferably 120,000 to 300,000. Thereby, the extrusion moldability is excellent. The weight average molecular weight of the component (M1-1) is measured by gel permeation chromatography using 1,2,4-trichlorobenzene as a solvent at 145°C and converted using a calibration curve of standard polystyrene.

[0023] The melt flow rate (MFR) of the component (M1-1) is not particularly limited. In one embodiment, the MFR of the multi-branched polystyrene is 0.1 to 20.0 g / 10 min, preferably 0.5 to 8.0 g / 10 min, more preferably 0.7 to 5.0 g / 10 min. Thereby, it becomes easier to impart extrusion processability. Specifically, the bubble stability and film thickness accuracy during inflation molding can be improved, and the stability of neck-in in extrusion lamination molding is excellent. The MFR of the component (M1-1) is measured according to JIS K7210 under the conditions of a temperature of 200°C and a load of 5 kg.

[0024] (Polystyrene (M1-2) having a syndiotactic structure with a weight average molecular weight of 130,000 or more) Polystyrene having a syndiotactic structure (hereinafter, also simply referred to as "syndiotactic polystyrene" or "SPS") is a crystalline styrene-based resin having a highly syndiotactic structure. "Syndiotactic" means that the phenyl rings in adjacent styrene units are arranged alternately (hereinafter referred to as syndiotacticity) with respect to the plane formed by the main chain of the polymer block at a high ratio.

[0025] Tacticity can be quantitatively identified by nuclear magnetic resonance method using isotope carbon ( 13 C-NMR method). 13 By the C-NMR method, the abundance ratios of a plurality of consecutive constitutional units, for example, two consecutive monomer units as a dyad, three monomer units as a triad, and five monomer units as a pentad can be quantified.

[0026] "Styrene resin having a highly syndiotactic structure" means polystyrene, poly(hydrocarbon-substituted styrene), poly(halogenated styrene), poly(halogenated alkyl styrene), poly(alkoxystyrene), poly(vinyl benzoate), etc. having a syndiotacticity of usually 75 mol% or more, preferably 85 mol% or more in racemic dyad (r), or usually 30 mol% or more, preferably 50 mol% or more in racemic pentad (rrrr), hydrogenated polymers or mixtures thereof, or copolymers having these as main components.

[0027] Examples of poly(hydrocarbon-substituted styrene) include poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene), poly(phenylstyrene), poly(vinylnaphthalene), and poly(vinylstyrene). Examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), and poly(fluorostyrene). Examples of poly(halogenated alkyl styrene) include poly(chloromethylstyrene). Examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene).

[0028] Examples of comonomer components of copolymers containing the above structural units include, in addition to the monomers of the above styrene-based polymers, olefin monomers such as ethylene, propylene, butene, hexene, and octene; diene monomers such as butadiene and isoprene; and polar vinyl monomers such as cyclic olefin monomers, cyclic diene monomers, methyl methacrylate, maleic anhydride, and acrylonitrile. Suitable copolymers include a copolymer of styrene and p-methylstyrene, a copolymer of styrene and p-tert-butylstyrene, a copolymer of styrene and divinylbenzene, and the like, with a copolymer of styrene and p-methylstyrene being preferred.

[0029] Among syndiotactic polystyrenes, one or more selected from polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene), poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene), and copolymers of styrene and p-methylstyrene are preferred, one or more selected from polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), and copolymers of styrene and p-methylstyrene are more preferred, polystyrene and copolymers of styrene and p-methylstyrene are even more preferred, and polystyrene is most preferred.

[0030] The melt flow rate (MFR) of component (M1-2) is preferably 1 g / 10 min or more, more preferably 2 g / 10 min or more, even more preferably 3 g / 10 min or more or 4 g / 10 min or more. It is also preferably 40 g / 10 min or less, more preferably 25 g / 10 min or less, and even more preferably 18 g / 10 min or less. If the MFR is 1 g / 10 min or more, there is no problem with the flowability of the resin during extrusion molding. If the MFR is 40 g / 10 min or less, preferably 20 g / 10 min or less, a molded product having sufficient strength can be obtained. The MFR measurement of the component (M1-2) is carried out under the conditions of a temperature of 300°C and a load of 1.2 kg.

[0031] The weight-average molecular weight of component (M1-2) is 130,000 or more, preferably 150,000 or more, more preferably 170,000 or more. When it is in such a range, it is excellent in film-forming property and strength. Further, the weight-average molecular weight of component (M1-2) is preferably 500,000 or less, more preferably 350,000 or less, still more preferably 300,000 or less. When it is in such a range, the fluidity of the resin during extrusion molding can be ensured. The weight-average molecular weight of component (M1-2) is a value measured by gel permeation chromatography measurement method at 145 ° C using 1,2,4-trichlorobenzene as a solvent and converted using a calibration curve of standard polystyrene.

[0032] Syndiotactic polystyrene can be produced by a known method. For example, it can be produced by polymerizing a styrene monomer using a condensation product of a titanium compound and water and trialkylaluminum as a catalyst in an inert hydrocarbon solvent or in the absence of a solvent.

[0033] (Polystyrene (M1-3) having an atactic structure with a weight-average molecular weight of 210,000 or more) Polystyrene having an atactic structure is a generally widely used polystyrene that does not have stereoregularity (tacticity) such as isotactic polystyrene (the arrangement of asymmetric carbon atoms is the same) or the above-mentioned syndiotactic polystyrene (the arrangement of asymmetric carbon atoms is alternating).

[0034] The melt flow rate (MFR) of component (M1-3) is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, still more preferably 1.0 g / 10 min or more. Further, it is preferably 10 g / 10 min or less, more preferably 5.0 g / 10 min or less, still more preferably 3.0 g / 10 min or less. If the MFR is 0.1 g / 10 min or more, there is no problem with the fluidity of the resin during extrusion molding, and if it is 10 g / 10 min or less, a molded product having sufficient strength can be obtained. The MFR measurement of component (M1-3) is carried out under the conditions of a temperature of 200 ° C and a load of 5 kg.

[0035] The weight average molecular weight of component (M1-3) is 210,000 or more, preferably 250,000 or more, more preferably 300,000 or more. When it is in such a range, it is excellent in film formability and strength. Further, the weight average molecular weight of component (M1-3) is preferably 600,000 or less, more preferably 500,000 or less, still more preferably 400,000 or less. When it is in such a range, the fluidity during extrusion molding can be ensured. The weight average molecular weight of component (M1-3) is a value measured by gel permeation chromatography measurement method at 145 °C using 1,2,4-trichlorobenzene as a solvent and converted using the calibration curve of standard polystyrene.

[0036] Note that, by definition, components (M1-1) to (M1-3) may overlap, but these are separate components. Those corresponding to component (M1) are treated as component (M1), and those corresponding to component (M2) among the others are treated as component (M2).

[0037] The content of component (M1) in the kneaded product (M) is, for example, 51% by mass or more, 55% by mass or more, or 60% by mass or more. The upper limit value is, for example, 79% by mass or less, 75% by mass or less, or 70% by mass or less. Note that component (M1) can be used alone or in combination of two or more of the above, and the above-described content is the total amount of component (M1).

[0038] As component (M1), any of components (M1-1) to (M1-3) can be used. In one embodiment, component (M1-1) is used, and for example, component (M1-1) and component (M1-3) are used in combination.

[0039] <Rubbery elastomer (M2)> A variety of rubber-like elastomers (hereinafter simply referred to as "component (M2)") can be used, but preferred is an elastomer containing structural units derived from styrene, such as at least one selected from the group consisting of styrene-diene block copolymers, hydrogenated styrene-diene block copolymers, styrene-diene random copolymers, hydrogenated styrene-diene random copolymers, and styrene-olefin random copolymers. Examples of dienes copolymerized with styrene include butadiene and isoprene, and examples of olefins copolymerized with styrene include ethylene, propylene, and butylene.

[0040] The component (M2) is more preferably at least one selected from the group consisting of styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), styrene-butadiene random copolymer, hydrogenated styrene-butadiene random copolymer, styrene-ethylene-propylene random copolymer, and styrene-ethylene-butylene random copolymer, and is further preferably styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEB The rubber-like elastomer is at least one selected from the group consisting of styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and even more preferably at least one selected from the group consisting of styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and even more preferably at least one selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and even more preferably hydrogenated styrene-butadiene-styrene block copolymer (SEBS). The rubber-like elastomer can be any of the above, or a combination of two or more thereof.The rubber elastic material may also be chemically modified, for example, with maleic acid.

[0041] The mass ratio of the structural units derived from styrene to the total of the structural units derived from diene, hydrogenated diene, and olefin constituting component (M2) [(styrene) / (diene, hydrogenated diene, olefin)] is preferably 10 / 90 to 65 / 35, and may be 20 / 80 to 55 / 45, or 25 / 75 to 50 / 50. The styrene content of component (M2) is preferably in the range of 10 to 65% by mass, and may be 25 to 50%. By achieving such a mass ratio, the compatibility with component (M1) and component (A), which will be described later, can be further improved, and toughness can be improved while maintaining heat resistance and dimensional stability at high temperatures.

[0042] The melt flow rate (MFR) of component (M2) is preferably 0.0 g / 10 min or more and preferably 30 g / 10 min or less, in which case the toughness improving effect is excellent. The MFR of component (M2) is measured under conditions of a temperature of 230°C and a load of 2.16 kg.

[0043] The content of the component (M2) in the kneaded material (M) is, for example, 21% by mass or more, 25% by mass or more, or 30% by mass or more, and the upper limit is, for example, 49% by mass or less, 45% by mass or less, or 40% by mass or less.

[0044] <Other ingredients (M3, etc.)> The kneaded material (M) may or may not contain a resin component other than the above-mentioned components (hereinafter, also simply referred to as "component (M3)"), various additives, and the like.

[0045] Examples of the component (M3) include styrene-based resins, ethylene-based resins, propylene-based resins, cyclic polyolefin-based resins, polyester-based resins, polyamide-based resins, acrylic-based resins, polycarbonate-based resins, and polyphenylene ether-based resins.

[0046] When the kneaded material (M) contains the component (M3), the content thereof is, for example, 0.1% by mass or more, 1% by mass or more, or 5% by mass or more, and the upper limit is, for example, 30% by mass or less, 20% by mass or less, or 10% by mass or less. In one embodiment, the kneaded product (M) does not include the component (M3).

[0047] Examples of additives include stabilizers (heat stabilizers, antioxidants), ultraviolet absorbers, hindered amine light stabilizers, antiblocking agents, lubricants, colorants, antistatic agents, and crystal nucleating agents.

[0048] When the kneaded material (M) contains the additive, the content thereof is, for example, 0.001% by mass or more, 0.01% by mass or more, or 0.1% by mass or more. The upper limit is, for example, 10% by mass or less, 3% by mass or less, or 1% by mass or less.

[0049] In one embodiment, the kneaded product (M) contains more than 80 mass % of a styrene-based resin, which makes it possible to realize a molded product having high transparency when mixed with the component (A) described below. The styrene-based resin refers to a resin containing a styrene-derived moiety as a monomer unit, and includes polystyrene having an atactic structure, polystyrene having an isotactic structure, syndiotactic polystyrene, hyperbranched polystyrene, elastomers containing structural units derived from styrene, and the like. The kneaded material (M) is, for example, more than 82 mass%, 85 mass% or more, 87 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, 99 mass% or more, 99.9 mass% or more, or 100 mass% of a styrene-based resin.

[0050] The kneaded material (M) may contain, for example, 80% by mass or more, 85% by mass or more, 87% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.9% by mass or more, or 100% by mass or more. Component (M1) and component (M2), Component (M1), component (M2), and additives; Component (M1), component (M2), and component (M3), or Component (M1), component (M2), component (M3), and an additive, may also be used.

[0051] <Resin composition> By melt-kneading the above-described kneaded product (M) and polystyrene (A) (component (A)) having a syndiotactic structure, a resin composition according to one embodiment of the present invention can be obtained. Note that the resin component to be melt-kneaded with the kneaded product (M) may be only component (A), or may contain other resin components in addition to component (A). In the resin composition, the rubber-like elastomer (M2) derived from the kneaded product (M) is not in a particulate state but is in an elongated linear state and is oriented in a random direction. By molding using such a resin composition, a molded body having a wide band-like shape and high toughness can be produced.

[0052] Note that the effect of the kneaded product (M) is not only exhibited when kneading with polystyrene having a syndiotactic structure, but also when kneading with other polystyrene resins, for example, atactic polystyrene (polystyrene in which the absolute configuration of each asymmetric carbon atom is irregular) or isotactic polystyrene (polystyrene in which each asymmetric carbon atom has the same absolute configuration), a resin composition capable of realizing a molded body with high toughness can be obtained. In addition, the effect of the kneaded product (M) can also be a resin composition capable of realizing a molded body with high toughness even when the kneaded product (M) is kneaded with two or more polystyrene resins (for example, component (A) and atactic polystyrene; component (A) and isotactic polystyrene; atactic polystyrene and isotactic polystyrene; or component (A), atactic polystyrene, and isotactic polystyrene).

[0053] The conditions for melt-kneading the kneaded product (M) and component (A) are not particularly limited, and a normal method can be adopted. For example, it is carried out under the conditions of 260 to 300°C. Alternatively, the resin composition may be obtained by melt-kneading the kneaded product (M) and the component (A) and pelletizing them.

[0054] In the above resin composition, the blending amount of the kneaded product (M) is, for example, 1% by mass or more, 5% by mass or more, 10% by mass or more, 20% by mass or more, 22% by mass or more, or 25% by mass or more. The upper limit is, for example, 50% by mass or less, 45% by mass or less, or 40% by mass or less.

[0055] In the above resin composition, the content of the rubber-like elastomer (M2) derived from the kneaded product (M) is, for example, 0.5% by mass or more, 1% by mass or more, 5% by mass or more, 8% by mass or more, 9% by mass or more, 10% by mass or more, or 11% by mass or more. The upper limit is, for example, 25% by mass or less, 20% by mass or less, or 15% by mass or less.

[0056] (Polystyrene (A) having a syndiotactic structure) Component (A) is the same as the above-described component (M1-2) except for the presence or absence of the condition of the weight-average molecular weight, and the matters described for the component (M1-2) are applicable.

[0057] The weight-average molecular weight of component (A) is preferably 100,000 or more, more preferably 110,000 or more, still more preferably 130,000 or more, or 150,000 or more. When it is in such a range, it is excellent in film-forming property and strength. Also, the weight-average molecular weight of syndiotactic polystyrene is preferably 500,000 or less, more preferably 350,000 or less, still more preferably 300,000 or less. When it is in such a range, the fluidity of the resin during extrusion molding can be ensured. The weight-average molecular weight of component (A) is a value measured by gel permeation chromatography measurement method at 145 °C using 1,2,4-trichlorobenzene as a solvent and converted using the calibration curve of standard polystyrene.

[0058] The content of component (A) in the resin composition is, for example, more than 40% by mass, 50% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, or 80% by mass or more. There is no particular upper limit, but it is, for example, 99% by mass or less, 95% by mass or less, or 90% by mass or less.

[0059] (Other resins (B), etc.) The resin composition according to one embodiment of the present invention may or may not contain a resin component other than the above-mentioned component (M) and component (A) (hereinafter simply referred to as "component (B)"), various additives, etc. Examples of component (B) include polystyrene (aPS) having an atactic structure, polyphenylene ether, and other thermoplastic resins. Note that, by definition, any material that corresponds to the above-mentioned component (A) is treated as component (A).

[0060] When the resin composition according to an embodiment of the present invention contains component (B), the content thereof is, for example, 1% by mass or more, 3% by mass or more, or 5% by mass or more. There is no particular upper limit, but the content is, for example, 40% by mass or less, or 20% by mass or less. In one embodiment, the resin composition does not contain component (B), or the content of the component may be 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less.

[0061] Examples of additives include stabilizers (heat stabilizers, antioxidants), ultraviolet absorbers, antiblocking agents, hindered amine light stabilizers, lubricants, colorants, antistatic agents, and crystal nucleating agents.

[0062] When the resin composition according to an embodiment of the present invention contains the additive, the content thereof is, for example, 0.001% by mass or more, 0.01% by mass or more, or 0.1% by mass or more. There is no particular upper limit, but the content is, for example, 5% by mass or less, or 3% by mass or less.

[0063] The resin composition according to one aspect of the present invention preferably has more than 80% by mass of a styrenic resin. By doing so, a molded article having high transparency can be realized. The definition of the styrenic resin is as described above. The resin composition according to one aspect of the present invention is, for example, more than 82% by mass, 85% by mass or more, 87% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.9% by mass or more, or 100% by mass of a styrenic resin.

[0064] The resin composition according to one aspect of the present invention is, for example, 80% by mass or more, 85% by mass or more, 87% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.9% by mass or more, or 100% by mass of component (A) and component (B), component (A), component (B), and an additive, component (A), component (B), and component (C), component (A), component (B), component (C), and an additive, component (A), component (B), component (C), and component (D), or component (A), component (B), component (C), component (D), and an additive may be used.

[0065] In the resin composition according to one aspect of the present invention, for example, the proportion of a thermoplastic resin other than polystyrene is 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.1% by mass or less, or 0% by mass. "Thermoplastic resin other than polystyrene" refers to a thermoplastic resin other than polystyrene and a rubber-like elastomer, and examples thereof include polyethylene.

[0066] [Use] The above resin composition can be used in various melt molding methods, and is preferably used, for example, for injection molding, inflation molding, extrusion lamination, hollow molding (direct blow), melt spinning, or foam molding such as extrusion foaming. Known methods can be adopted for these methods.

[0067] [Formed article, etc.] The formed article according to one aspect of the present invention is a formed article obtained by melt-molding the above-described resin composition. The shape of the formed article is not particularly limited. For example, it may be in the shape of a sheet, film, or fiber. Further, it may be a laminate of a layer obtained from the resin composition and another layer. Examples of the other layer include a base material layer serving as a base of the laminate, an adhesive layer for interlayer adhesion, a printing layer for decoration, a release layer, etc., and an appropriate configuration can be adopted according to the application.

[0068] The formed article obtained from the above resin composition can be used, for example, as packaging materials such as vegetable packaging, twist packaging, pharmaceutical packaging materials, reagent containers (packaging materials, flexible containers), food containers, food container surface base materials, food container lids, heat-resistant cooking films, cup noodle container surface materials, adhesive labels, simple adhesive tapes, etc., and industrial materials such as masking films, labels, magazine tapes, release films, insulating films, chemical-resistant films, paper laminates, printed circuit board base materials, films for film capacitors, component trays, non-woven fabrics, clothing fibers, industrial fibers, clothing fabrics, industrial fabrics, household holding packaging materials, agricultural materials, battery-related materials, etc. In addition, various formed articles such as containers can be manufactured by thermoforming the sheet (film) obtained from the above resin composition or the laminate described above. The method of thermoforming is not particularly limited, and examples include vacuum forming, hot plate pressure air forming, etc.

[0069] [Method for manufacturing a formed article] The method for manufacturing a formed article according to one aspect of the present invention can also be expressed as follows. At least one polystyrene (M1) selected from branched polystyrene (M1-1), polystyrene (M1-2) having a syndiotactic structure with a weight average molecular weight of 130,000 or more, and polystyrene (M1-3) having an atactic structure with a weight average molecular weight of 210,000 or more, and a kneaded product (M) obtained by melt-kneading components containing a rubber-like elastic body (M2), Polystyrene (A) having a syndiotactic structure; a step of melt-kneading the above to prepare a resin composition; and The resin composition is melt-molded. A method for manufacturing a molded body. The melt mixing and extrusion molding methods are as described above. [Example]

[0070] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0071] [Ingredients used] The materials used in the following examples and comparative examples are as follows. <Polystyrene (M1)> (hyperbranched polystyrene (M1-1)) B-PS1: Hyperbranched polystyrene, MFR: 1.1g / 10min (temperature 200℃, load 5kg)

[0072] (Polystyrene (M1-3) with an atactic structure having a weight-average molecular weight of 210,000 or more) aPS1: Polystyrene with atactic structure, MFR: 1.5g / 10min (temperature 200℃, load 5kg), weight average molecular weight: 320,000

[0073] <Rubber-like elastic body (M2)> SEBS1: Hydrogenated styrene-butadiene-styrene block copolymer, "Tuftec H1041" manufactured by Asahi Kasei Corporation, styrene content 30% by mass, MFR: 5.0 g / 10 min (temperature 230°C, load 2.16 kg) SEBS2: Hydrogenated styrene-butadiene-styrene block copolymer, "Tuftec H1053" manufactured by Asahi Kasei Corporation, styrene content 29% by mass, MFR: 1.8 g / 10 min (temperature 230°C, load 2.16 kg) ·SEBS3: Hydrogenated styrene-butadiene-styrene block copolymer, "Septon 2104" manufactured by Kuraray Co., Ltd., styrene content 65% by mass, MFR: 0.4 g / 10 min (temperature 230 °C, load 2.16 kg) ·SEBS4: Hydrogenated styrene-butadiene-styrene block copolymer, "Taftec M1913" manufactured by Asahi Kasei Corporation, styrene content 30% by mass, MFR: 5.0 g / 10 min (temperature 230 °C, load 2.16 kg)

[0074] <Polystyrene (A) having a syndiotactic structure> ·SPS1: Syndiotactic polystyrene, manufactured by Idemitsu Kosan Co., Ltd., MFR: 14.0 g / 10 min (300 °C, load 1.2 Kg), weight average molecular weight: 170,000 (measured by gel permeation chromatography at 145 °C using 1,2,4-trichlorobenzene as a solvent), melting point: 246 °C (DSC measurement) 13 It was confirmed by C-NMR measurement that SPS1 is a polystyrene with a syndiotactic structure.

[0075] <Other resin (B)> ·HIPS1: High-impact polystyrene, "HT478" manufactured by PS Japan Corporation, MFR: 3.0 g / 10 min (temperature 200 °C, load 5 kg) ·LDPE1: Low-density polyethylene, "LF405H" manufactured by Nippon Polyethylene Co., Ltd.

[0076] Examples 1 to 9 1. Production of masterbatch (kneaded product (M)) The components (M1) and (M2) described in Table 1 were charged into a twin-screw extruder and melt-kneaded under the conditions of 230°C, a discharge rate of 25 kg / h, and a screw rotation speed of 250 rpm. The melt-kneaded resin composition was extruded into strands, and the resin composition cooled in a water bath was cut into pellets to obtain a masterbatch (kneaded product (M)). The quantity ratios shown in Table 1 represent the mass percentages of the respective components when the resin composition is 2. The content ratios of the respective components in the masterbatch (kneaded product (M)) are, for example, in Example 1: B-PS1: 20% by mass, aPS1: 40% by mass, SEBS1: 40% by mass.

[0077] 2. Production of Resin Composition and Molded Body The masterbatch (kneaded product (M)) obtained in 1. and the component (A) described in Table 1 were charged into a single-screw (full-flight type screw) extruder with a diameter of 40 mm equipped with an annular die with a diameter of 50 mm and a gap of 2 mm. Under the conditions of 270°C and an extrusion rate of 7 kg / hour, the molten resin (resin composition) was melt-extruded vertically (upward), air was fed into the inside of the annularly extruded resin so that the blow ratio became 3.3, and the resin film in the form of a bubble was taken up at a take-up speed of 10.0 m / min to obtain an inflation film (molded body). During inflation molding, an air ring was used, a heat insulating material was attached to the stabilizing plate to stabilize the bubble. Each evaluation was performed on the film taken up at a speed of 10.0 m / min.

[0078] 3. Evaluation of Molded Body The following evaluations were performed on the obtained inflation film (molded body).

[0079] (Elongation at Break in Tensile Test (%)) It was carried out by a method conforming to JIS7127. Specifically, a test piece was prepared by cutting out the film into a strip shape with a length of 150 mm and a width of 10 mm so that the resin flow direction (MD direction) became the long side, and the test was performed at a chuck distance of 100 mm and a tensile speed of 50 mm / min. The strain at the time when the film broke was taken as the elongation at break in the tensile test from the obtained stress-strain curve.

[0080] (Tensile Strength at Break (Mpa)) The test was carried out in accordance with JIS K7127. Specifically, test pieces were prepared by cutting the film into strips 150 mm long and 10 mm wide with the resin flow direction (MD) as the long side, and the test was carried out with a chuck distance of 100 mm and a tensile speed of 50 mm / min. The stress at which the film broke from the obtained stress-strain curve was taken as the tensile breaking strength.

[0081] (Tensile yield strength (MPa)) The test was carried out in accordance with JIS K7127. Specifically, test pieces were prepared by cutting the film into strips 150 mm long and 10 mm wide with the resin flow direction (MD) as the long side, and the test was carried out with a chuck distance of 100 mm and a tensile speed of 50 mm / min. From the obtained stress-strain curve, the stress at the point where an increase in strain without an increase in stress first occurred was taken as the tensile yield strength. In the table, "-" indicates that there was no yield point (the specimen broke before reaching the yield point).

[0082] (Toughness: toughness) The product of the tensile breaking elongation (%) and the tensile breaking strength (Mpa) in the above evaluation (tensile breaking elongation x tensile breaking strength) was calculated as an evaluation value of toughness.

[0083] (Haze (%)) Using a measuring device ("HAZE METER NDH5000" manufactured by Nippon Denshoku Industries Co., Ltd.), the haze was measured at a location where the film was 25 μm thick in accordance with JIS K7136.

[0084] Comparative Examples 1 to 5 Since the conditions vary depending on the method for mixing the resin composition, the explanation will be given for each case.

[0085] (Comparative example where "MB" is used as the "resin composition mixing method") Except for changing the composition as shown in Table 2, the masterbatch (kneaded product (M)), resin composition, and molded body were produced in the same manner as in Examples 1 to 9, and the same evaluations as in Examples 1 to 9 were performed on the obtained molded body. Component (M1) and component (M2) are components for the masterbatch (kneaded product (M)), and component (A) and component (B) are resin components to be kneaded with the masterbatch (kneaded product (M)). The results are shown in Table 2.

[0086] (Comparative example where the "mixing method of resin composition" is "DB") The resin composition and the molded body were produced in the same manner as in Examples 1 to 9, except that all the components described in the "resin composition" of Table 2 were charged into the extruder in "2. Production of resin composition and molded body" of Examples 1 to 9, and the same evaluations as in Examples 1 to 9 were performed on the obtained molded body. The results are shown in Table 2.

[0087] (Comparative example where the "mixing method of resin composition" is "FC") All the components described in the "resin composition" of Table 2 were melt-kneaded with a twin-screw extruder to obtain pellets (resin composition). The resin composition and the molded body were produced in the same manner as in Examples 1 to 9, except that the obtained pellets were charged into the extruder in "2. Production of resin composition and molded body" of Examples 1 to 9, and the same evaluations as in Examples 1 to 9 were performed on the obtained molded body. The results are shown in Table 2.

[0088]

Table 1

[0089]

Table 2

Claims

1. At least one polystyrene (M1) selected from among at least multi-branched polystyrene (M1-1), polystyrene having a syndiotactic structure with a weight average molecular weight of 130,000 or more (M1-2), and polystyrene having an atactic structure with a weight average molecular weight of 210,000 or more (M1-3), and a kneaded product (M) obtained by melt-kneading each component containing a rubber-like elastomer (M2), polystyrene having a syndiotactic structure (A), A resin composition obtained by melt-kneading.

2. The resin composition according to claim 1, wherein the content of the rubber-like elastomer (M2) in the kneaded product (M) is 21 to 49% by mass.

3. The resin composition according to claim 1 or 2, wherein the styrene content of the rubber-like elastomer (M2) is 10 to 65% by mass.

4. The resin composition according to any one of claims 1 to 3, wherein the content of the rubber-like elastomer (M2) is 0.5 to 25% by mass.

5. The resin composition according to any one of claims 1 to 4, wherein the content of the polystyrene (M1) in the kneaded product (M) is 51 to 79% by mass.

6. The resin composition according to any one of claims 1 to 5, wherein the polystyrene (M1) contains the multi-branched polystyrene (M1-1).

7. The resin composition according to any one of claims 1 to 6, wherein the polystyrene (M1) contains the multi-branched polystyrene (M1-1) and polystyrene having an atactic structure with a weight average molecular weight of 210,000 or more (M1-3).

8. The resin composition according to any one of claims 1 to 7, wherein the blending amount of the kneaded product (M) is 1 to 50% by mass.

9. The resin composition according to any one of claims 1 to 8, wherein the content of the polystyrene (A) having a syndiotactic structure is more than 40% by mass and 99% by mass or less.

10. The resin composition according to any one of claims 1 to 9, wherein the content of polyethylene is less than 20% by mass.

11. The resin composition according to any one of claims 1 to 10, which is for melt molding.

12. The resin composition according to any one of claims 1 to 11, wherein the kneaded product (M) is a masterbatch.

13. A molded article obtained from the resin composition according to any one of claims 1 to 12.

14. At least one polystyrene (M1) selected from branched polystyrene (M1-1), polystyrene having a syndiotactic structure with a weight average molecular weight of 130,000 or more (M1-2), and polystyrene having an atactic structure with a weight average molecular weight of 210,000 or more (M1-3), and a kneaded product (M) obtained by melt-kneading each component containing a rubber-like elastomer (M2), Polystyrene having a syndiotactic structure (A), A step of preparing a resin composition by melt-kneading, and Including a step of melt-molding the resin composition, A method for manufacturing a molded article.

15. At least one polystyrene (M1) selected from branched polystyrene (M1-1), polystyrene having a syndiotactic structure with a weight average molecular weight of 130,000 or more (M1-2), and polystyrene having an atactic structure with a weight average molecular weight of 210,000 or more (M1-3), and Including a rubber-like elastomer (M2), Masterbatch (M').

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