Resin composition for extrusion molding and extrusion molded body

Abstract

To provide a resin composition for extrusion molding which enables manufacture of an extrusion molded body that is excellent in a low molding shrinkage, chemical resistance and impact resistance, and is excellent in extrusion moldability.SOLUTION: A resin composition for extrusion molding contains a styrenic block copolymer, a styrenic resin other than the styrenic block copolymer, and a propylene-based resin, and has a melt flow rate (200°C, and load of 5 kgf) of less than 5 g / 10 min. With respect to 100 mass% of the total of the styrenic resin and the propylene-based resin, 35 mass% or more and 65 mass% or less of the propylene-based resin is contained. The melt flow rate (200°C and load of 5 kgf) of the styrenic resin is less than 4 g / 10 min. A ratio of the melt flow rate (200°C and load of 5 kgf) of the propylene-based resin to the melt flow rate (200°C and load of 5 kgf) of the styrenic resin is 1.5 or more and 5 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an extruded resin composition and an extruded article. More specifically, the present disclosure relates to an extruded resin composition containing a propylene-based resin and an extruded article.

Background Art

[0002] Propylene-based resins have a low specific gravity and are excellent in mechanical properties such as impact resistance and chemical resistance. Therefore, molded articles made of the propylene-based resin are used in various fields such as household goods, food, agriculture, fisheries, medical, industrial, and construction. However, molded articles made of propylene-based resins have problems in that it is difficult to obtain dimensional stability and they are easily deformed because of a large molding shrinkage rate.

[0003] In addition, molded articles made of styrene-based resins have good moldability, a small molding shrinkage rate, and excellent dimensional stability. Therefore, taking advantage of these characteristics, they are widely used in food, household appliances, industrial parts, household goods, etc. However, molded articles made of styrene-based resins have problems such as poor chemical resistance.

[0004] Therefore, in order to solve the above problems, resin compositions in which a propylene-based resin and a styrene-based resin are mixed have been studied.

[0005] Patent Document 1 describes a resin composition containing a styrene-based block copolymer, a styrene-based resin other than the styrene-based block copolymer, and a propylene-based resin having a melt flow rate (at 230°C and a load of 2.16 kgf) of 3 g / 10 min or more, and containing the propylene-based resin in an amount of 35 to 65% by mass based on the total 100% by mass of the styrene-based resin and the propylene-based resin (Claim 1). It is also described that the melt flow rate (at 200°C and a load of 5 kgf) of this resin composition is 5 g / 10 min or more.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] When extrusion molding is performed using the resin composition described in Patent Document 1, there is a problem that it is difficult to perform extrusion molding because the melt flow rate is large and the fluidity is too high.

[0008] An object of the present disclosure is to provide an extrusion molding resin composition and an extrusion molded article that can obtain an extrusion molded article excellent in low molding shrinkage rate, chemical resistance, and impact resistance, and further excellent in extrusion moldability.

Means for Solving the Problems

[0009] An extrusion molding resin composition according to one aspect of the present disclosure includes a styrene block copolymer, a styrene resin other than the styrene block copolymer, and a propylene resin, and has a melt flow rate (at 200°C, load 5 kgf) of less than 5 g / 10 minutes. The propylene resin is contained in an amount of 35% by mass or more and 65% by mass or less based on 100% by mass in total of the styrene resin and the propylene resin. The melt flow rate (at 200°C, load 5 kgf) of the styrene resin is less than 4 g / 10 minutes. The ratio of the melt flow rate (at 200°C, load 5 kgf) of the propylene resin to the melt flow rate (at 200°C, load 5 kgf) of the styrene resin is 1.5 or more and 5 or less.

[0010] An extrusion molded article according to one aspect of the present disclosure includes the extrusion molding resin composition.

Advantages of the Invention

[0011] According to the present disclosure, an extrusion molded article excellent in low molding shrinkage rate, chemical resistance, and impact resistance can be obtained, and the extrusion moldability is excellent.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the resin composition for extrusion molding and the extruded molded article according to the embodiments of the present disclosure will be described. Note that all of the embodiments described below show preferred specific examples of the present disclosure. Therefore, the numerical values, materials, components, arrangements of components, connection forms, processes, order of processes, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Thus, among the following embodiments, components not described in the independent claims indicating the highest-level concept of the present disclosure are described as optional components.

[0013] (1) Overview The resin composition for extrusion molding according to the present embodiment contains a styrenic block copolymer, a styrenic resin other than the above styrenic block copolymer, and a propylene resin. Therefore, the resin composition for extrusion molding of the present embodiment contains a styrenic block copolymer and a styrenic resin other than the above styrenic block copolymer, so that it is easier to obtain an extruded molded article having excellent impact resistance compared to a molded article of a resin composition containing only a propylene resin.

[0014] Also, the resin composition for extrusion molding of the present embodiment has a melt flow rate (200 °C, load 5 kgf) of less than 5 g / 10 min. Therefore, the resin composition for extrusion molding of the present embodiment does not have too high fluidity and has excellent extrusion moldability, and for example, it is easy to mold an extruded molded article such as a sheet.

[0015] In addition, in the resin composition for extrusion molding of the present embodiment, the above-mentioned propylene-based resin is contained in an amount of 35% by mass or more and 65% by mass or less based on 100% by mass in total of the above-mentioned styrene-based resin and the above-mentioned propylene-based resin. Further, the melt flow rate (at 200°C, load 5 kgf) of the above-mentioned styrene-based resin is less than 4 g / 10 min. The ratio of the melt flow rate (at 200°C, load 5 kgf) of the above-mentioned propylene-based resin to the melt flow rate (at 200°C, load 5 kgf) of the above-mentioned styrene-based resin is 1.5 or more and 5 or less. Therefore, the resin composition for extrusion molding of the present embodiment has good characteristics of both the propylene-based resin and the styrene-based resin, and an extruded molded article excellent in well-balanced low molding shrinkage rate, chemical resistance, and impact resistance can be obtained.

[0016] (2) Details The resin composition for extrusion molding of the present embodiment contains a styrene-based block copolymer, a styrene-based resin other than the styrene-based block copolymer, and a propylene-based resin.

[0017] <Propylene-based resin> The propylene-based resin used in the present embodiment may be either a homopolymer of propylene (monomer) or a copolymer (block copolymer and random copolymer) of propylene and other monomers (comonomers), and the stereoregularity of these polymers is not particularly limited. Among these, an extruded molded article having a small molding shrinkage rate can be easily obtained while being a composition containing a propylene-based resin, and thus, a homopolymer of propylene is preferable in that an extruded molded article excellent in the effects of the present embodiment can be easily obtained. The propylene-based resin may be used alone or in combination of two or more.

[0018] The above copolymer is obtained by copolymerizing propylene and a comonomer copolymerizable with propylene. Examples of the comonomer copolymerizable with propylene include olefins such as ethylene, butene, pentene, hexene, and octene. Among these, in order to obtain an extruded article with a small molding shrinkage rate, it is preferable to use ethylene or 1-butene as the copolymer. Further, two or more of the above comonomers may be used. The amount of the comonomer used is usually 30% by mass or less, preferably 20% by mass or less, based on 100% by mass of all the monomers used in the synthesis of the copolymer contained in the propylene-based resin.

[0019] The melt flow rate (at 230°C, load 2.16 kgf) of the propylene-based resin used in this embodiment is preferably 1 g / 10 min or more and 10 g / 10 min or less. The melt flow rate (hereinafter, may be referred to as "MFR") is a measure for measuring the fluidity of molten plastic and is measured in accordance with ISO 1133-1:2011. "(230°C, load 2.16 kgf)" indicates the measurement conditions, meaning that the resin melted at a temperature of 230°C was caused to flow out under a load of 2.16 kgf. Also, "(200°C, load 5 kgf)" means that the resin melted at a temperature of 200°C was caused to flow out under a load of 5 kgf.

[0020] When the MFR (at 230°C, load 2.16 kgf) of the propylene-based resin used in this embodiment is 1 g / 10 min or more and 10 g / 10 min or less, an extrusion molding resin composition excellent in extrusion moldability can be easily obtained, and it also has excellent low molding shrinkage rate, chemical resistance, and impact resistance. In particular, an extruded article excellent in chemical resistance can be easily obtained. If the MFR (at 230°C, load 2.16 kgf) of the propylene-based resin is less than 1 g / 10 min or exceeds 10 g / 10 min, it becomes difficult to obtain the above effects. The MFR (at 230°C, load 2.16 kgf) of the propylene-based resin is more preferably 2 g / 10 min or more and more preferably 7.5 g / 10 min or less. Thereby, the above effects can be easily obtained.

[0021] The propylene-based resin used in this embodiment preferably has a ratio of the MFR (200 °C, load 5 kgf) of the propylene-based resin to the MFR (200 °C, load 5 kgf) of the styrene-based resin (MFR of propylene-based resin / MFR of styrene-based resin) of 1.5 or more and 5 or less. By using a propylene-based resin that satisfies such a relationship, an extruded molded article having a sea-island structure can be easily formed, and an extruded molded article excellent in low molding shrinkage rate, chemical resistance, impact resistance, and appearance can be easily obtained. The ratio of the MFR (200 °C, load 5 kgf) of the propylene-based resin to the MFR (200 °C, load 5 kgf) of the styrene-based resin is preferably 1.7 or more. Further, the ratio of the MFR (200 °C, load 5 kgf) of the propylene-based resin to the MFR (200 °C, load 5 kgf) of the styrene-based resin is preferably 3.5 or less.

[0022] The propylene-based resin used in this embodiment preferably has an Izod impact strength (23 °C) measured based on ASTM D256 of 2 kJ / m 2 or more. Thereby, an extruded molded article excellent in impact resistance can be easily obtained.

[0023] The propylene-based resin used in this embodiment preferably has a flexural modulus measured based on ASTM D790 of 1000 MPa or more. Thereby, an extruded molded article excellent in mechanical strength can be easily obtained.

[0024] <Styrene-based block copolymer> The styrene-based block copolymer used in this embodiment includes, for example, a block copolymer having a polymer block composed of a styrene-based monomer and a polymer block composed of a conjugated diene-based monomer or a polymer block obtained by hydrogenating part or all of a polymer block composed of a conjugated diene-based monomer.

[0025] The above block copolymer may be used alone or in combination of two or more. Further, the above block copolymer may be obtained by synthesis by a conventionally known method or a commercially available product may be used.

[0026] Examples of the styrene monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dichlorostyrene, and 2,5-dichlorostyrene, with styrene being preferred.

[0027] Examples of the conjugated diene monomer include butadiene, isoprene, piperylene, methylpentadiene, and phenyldiene, with butadiene or isoprene being preferred.

[0028] As the styrene block copolymer used in this embodiment, a styrene-butadiene block copolymer and a hydrogenated product of the styrene-butadiene block copolymer are preferred. Examples of the styrene-butadiene block copolymer include a styrene-butadiene copolymer (SB) and a styrene-butadiene-styrene block copolymer (SBS). A copolymer having four or more blocks may also be used. Among these, SBS is preferred due to the reinforcing effect on the resin composition for extrusion molding.

[0029] The content of the structural unit derived from styrene in the styrene-butadiene block copolymer is preferably 20% by mass or more and 60% by mass or less, more preferably 30% by mass or more and 50% by mass or less, based on 100% by mass in total of the structural unit derived from styrene and the structural unit derived from butadiene.

[0030] Examples of the hydrogenated product of the styrene-butadiene block copolymer include polymers in which part or all of the butadiene portion of the styrene-butadiene block copolymer is hydrogenated. Specifically, styrene-ethylene / butylene block copolymer (SEB), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-butadiene / butylene-styrene block copolymer (SBBS), and hydrogenated products of modified styrene-butadiene block copolymers with functional groups can be mentioned. Examples of the functional group include a hydroxyl group, an acid anhydride group, a carboxy group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, and an epoxy group. Among these, SEBS is preferred in terms of easy availability and compatibility with propylene-based resins.

[0031] In the styrene-butadiene block copolymer before hydrogenation in the above hydrogenated product, the content of the structural unit derived from styrene is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, based on 100% by mass in total of the structural unit derived from styrene and the structural unit derived from butadiene.

[0032] As the hydrogenated product of the styrene-butadiene block copolymer, those in which 50% or more of the double bonds in the butadiene block portion are hydrogenated are preferred, and those in which 90% or more are hydrogenated are more preferred. When the hydrogenation rate is within the above range, it is preferred because of excellent compatibility with propylene-based resins.

[0033] The styrene block copolymer used in this embodiment preferably has an MFR measured at 200 °C under a load of 5 kgf based on ISO 1133-1:2011 of 0.1 g / 10 min or more and 100 g / 10 min or less, more preferably 10 g / 10 min or more and 70 g / 10 min or less, from the viewpoint of easily obtaining an extrusion molding resin composition excellent in processability and extrusion moldability.

[0034] <Styrene resin> The styrenic resin used in this embodiment is not particularly limited as long as it is a resin other than the above-mentioned styrenic block copolymer, but preferably a general-purpose polystyrene resin (hereinafter also referred to as "GPPS") or an impact-resistant polystyrene resin (hereinafter also referred to as "HIPS"). Among these, HIPS is preferred in terms of easily obtaining an extrusion molding resin composition with excellent impact resistance. The styrenic resin may be used alone or in combination of two or more. Also, the above-mentioned styrenic resin may be synthesized by a conventionally known method or a commercially available product may be used.

[0035] The styrenic resin used in this embodiment has an MFR measured at 200 °C and a load of 5 kgf based on ISO 1133-1:2011 of less than 4 g / 10 min. Thereby, an extruded molded article excellent in low molding shrinkage rate, chemical resistance and impact resistance can be obtained, and an extrusion molding resin composition excellent in extrusion moldability can be easily obtained. The MFR (200 °C, load 5 kgf) of the styrenic resin is preferably 1 to 2.5 g / 10 min.

[0036] The styrenic resin used in this embodiment preferably has an Izod impact strength (23 °C) measured based on ASTM D256 of 5 kJ / m or more from the viewpoint of easily obtaining a molded article with excellent impact resistance. 2 More preferably 10 kJ / m or more. 2 or more.

[0037] The styrenic resin used in this embodiment preferably has a flexural modulus measured based on ASTM D790 of 2000 MPa or more from the viewpoint of easily obtaining a molded article with excellent mechanical strength.

[0038] < <gpps>> The above-mentioned GPPS is a styrenic polymer obtained by radical polymerization by methods such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. Specifically, it includes (co)polymers of one or more aromatic vinyl monomers and hydrides of these (co)polymers, and preferably it is a polymer of one aromatic vinyl monomer. However, it is a polymer other than HIPS. The above-mentioned GPPS may contain conventionally known additives.

[0039] Examples of the above-mentioned aromatic vinyl monomers include α-alkyl-substituted styrenes such as styrene, α-methylstyrene, α-ethylstyrene, α-methyl-p-methylstyrene, etc., nuclear alkyl-substituted styrenes such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, o-t-butylstyrene, p-t-butylstyrene, etc., nuclear halogenated styrenes such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, dichlorostyrene, dibromostyrene, trichlorostyrene, tribromostyrene, tetrachlorostyrene, tetrabromostyrene, 2-methyl-4-chlorostyrene, etc., p-hydroxystyrene, o-methoxystyrene, vinylnaphthalene. Among these, styrene and α-methylstyrene are particularly preferred.

[0040] < <hips>> Examples of the HIPS include, for example, a rubber-modified styrene resin obtained by graft-polymerizing an aromatic vinyl monomer (polymer) onto a rubber-like polymer. For example, a rubber-like polymer and an aromatic vinyl monomer (polymer) are mixed and polymerized by a known method, such as a multi-stage polymerization method such as an emulsion polymerization method, a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or a bulk-suspension two-stage polymerization method.

[0041] Examples of the aromatic vinyl monomer include the same monomers as those listed in the column of GPPS. Among these, styrene and α-methylstyrene are particularly preferred. These aromatic vinyl monomers may be used alone or in combination of two or more.

[0042] Examples of the rubber-like polymer include polybutadiene such as cis-type, trans-type, and low-vinyl type obtained by emulsion polymerization or solution polymerization, and random-type or block-type butadiene-styrene copolymer rubbers obtained by emulsion polymerization or solution polymerization. Natural rubber, polyisobutylene rubber, styrene-isoprene copolymer rubber, butyl rubber, ethylene-propylene copolymer rubber, and graft copolymer rubbers of these rubbers and styrene are also included. Among these, polybutadiene and butadiene-styrene copolymer rubbers are preferred. These rubber-like polymers may be used alone or in combination of two or more.

[0043] HIPS is preferably a resin obtained by polymerizing a mixture containing 70% by mass or more and 98% by mass or less of the aromatic vinyl monomer and 2% by mass or more and 30% by mass or less of the rubber-like polymer, and more preferably contains a graft polymer obtained by graft-polymerizing a part of the monomer onto the rubber-like polymer. If the amount of the rubber-like polymer is less than 2% by mass, sufficient impact resistance may not be obtained, and if it exceeds 30% by mass, the rigidity may decrease.

[0044] <Additive> In the resin composition for extrusion molding of the present embodiment, depending on the desired application, conventionally known additives other than the above-mentioned propylene-based resin, styrene-based block copolymer, and styrene-based resin may be blended within a range that does not impair the effects of the present disclosure. Each of the above-mentioned additives may be used alone or in combination of two or more.

[0045] Examples of the above-mentioned additives include fillers (e.g., pigments, dyes), other polymers, light stabilizers, UV absorbers, antibacterial substances, plasticizers, nucleating agents, heavy metal inactivators, stabilization aids, antistatic agents, conductive agents, flame retardants, heat stabilizers, antioxidants, lubricants, crosslinkable polymers, and fiber reinforcing agents. When blending the above-mentioned additives into the present composition, additives that have been hydrophobized in advance may be used.

[0046] <<Filler>> The above-mentioned filler is not particularly limited, and various known fillers that have been used in resin compositions, such as inorganic fillers and organic fillers, can be used. Examples of the filler include talc, mica, clay, calcium carbonate, barium sulfate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, glass fiber, carbon fiber, and wood powder. Among these, talc and calcium carbonate are preferable, and calcium carbonate is more preferable, particularly from the viewpoint of easily obtaining a composition that satisfies extremely high levels of flexural modulus and chemical resistance.

[0047] In the present embodiment, when the above-mentioned filler is included, its content is preferably 2 parts by mass or more and 40 parts by mass or less, more preferably 5 parts by mass or more and 20 parts by mass or less, based on a total of 100 parts by mass of the propylene-based resin and the styrene-based resin in the resin composition for extrusion molding. Note that even when the above-mentioned filler is contained, it is preferable to include it so that the MFR (200 °C, load 5 kgf) of the resin composition for extrusion molding is less than 5 g / 10 min.

[0048] <<Other polymers>> The resin composition for extrusion molding of the present embodiment may contain other polymers such as polyethylene, ethylene-propylene copolymer (copolymer with propylene as a comonomer), ethylene-butene copolymer, ethylene-pentene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, butene-hexene copolymer, butene-octene copolymer, hexene-octene copolymer, etc., within a range that does not impair the effects of the present disclosure. When the resin composition for extrusion molding contains the above other polymers, its content is preferably 30 parts by mass or less with respect to 100 parts by mass of the above propylene-based resin.

[0049] <<Flame retardant>> Depending on the applications of the resin composition for extrusion molding and the extruded molded article of the present embodiment, flame retardancy may be required. In this case, it is preferable to compound a flame retardant. For example, the resin composition for extrusion molding and the extruded molded article preferably have a flame retardancy of V-2 or higher according to the UL94 standard. The type and amount of the flame retardant may be appropriately determined in consideration of the flame retardancy required for the resin composition for extrusion molding and the extruded molded article.

[0050] <<Antibacterial substance>> Depending on the applications of the resin composition for extrusion molding and the extruded molded article of the present embodiment, an antibacterial effect may be required. In this case, it is preferable to compound an antibacterial substance. The antibacterial substance is not particularly limited, but examples include antibacterial agents. As the antibacterial agent, conventionally known antibacterial agents can be used, but silver-based antibacterial agents are preferably used.

[0051] <Resin composition for extrusion molding> The resin composition for extrusion molding of the present embodiment can be obtained by mixing the above components. However, it is preferable to sufficiently knead the above components using conventionally known apparatuses, specifically, a single-screw extruder, a twin-screw extruder, a kneader, a mixer, a two-roll mill, etc., so as to be uniform.

[0052] In the resin composition for extrusion molding of the present embodiment, the content of the propylene-based resin is 35% by mass or more and 65% by mass or less, preferably 40% by mass or more and 60% by mass or less, based on 100% by mass in total of the propylene-based resin and the styrene-based resin in the resin composition for extrusion molding.

[0053] When the content of the propylene-based resin is within the above range, the above effects can be achieved while maintaining or improving the physical properties of the propylene-based resin. In particular, an extruded molded article that satisfies a very low molding shrinkage rate and chemical resistance at an extremely high level can be easily obtained. If the content of the propylene-based resin is less than the above range, there is a risk that the extruded molded article will be particularly inferior in chemical resistance. If the content of the propylene-based resin exceeds the above range, there is a risk that the extruded molded article will have a particularly large molding shrinkage rate.

[0054] In the resin composition for extrusion molding of the present embodiment, the content of the styrene-based resin is preferably 35% by mass or more and 65% by mass or less, more preferably 40% by mass or more and 60% by mass or less, based on 100% by mass in total of the propylene-based resin and the styrene-based resin in the resin composition for extrusion molding.

[0055] When the content of the styrene-based resin is within the above range, the above effects can be achieved while maintaining or improving the physical properties of the propylene-based resin. In particular, an extruded molded article that satisfies a very low molding shrinkage rate and good appearance at an extremely high level can be easily obtained.

[0056] In the resin composition for extrusion molding of the present embodiment, the content of the styrene-based block copolymer is preferably 2 parts by mass or more and 15 parts by mass or less, more preferably 5 parts by mass or more and 12 parts by mass or less, based on 100 parts by mass in total of the propylene-based resin and the styrene-based resin in the resin composition for extrusion molding. When the content of the styrene-based block copolymer is within the above range, an extruded molded article excellent in low molding shrinkage rate, chemical resistance and impact resistance can be obtained while maintaining or improving the physical properties of the propylene-based resin, and a resin composition for extrusion molding excellent in extrusion moldability can be easily obtained.

[0057] The resin composition for extrusion molding of the present embodiment has an MFR measured at 200 °C and a load of 5 kgf based on ISO 1133-1:2011. From the viewpoint of easily obtaining a resin composition for extrusion molding with excellent extrusion moldability, etc., it is less than 5 g / 10 min, preferably 4.5 g / 10 min or less, more preferably 4 g / 10 min or less, and even more preferably 3 g / 10 min or less.

[0058] <Extrusion molded article> The extrusion molded article of the present embodiment is obtained by extrusion molding the above resin composition for extrusion molding. The extrusion molded article of the present embodiment can be molded into a desired shape. For example, it can be molded into a sheet shape. Also, the extrusion molded article of the present embodiment may be used alone, or may be used by laminating the extrusion molded article of the present embodiment with other members.

[0059] The extrusion molded article of the present embodiment preferably has a sea-island structure containing a sea portion containing the above propylene-based resin and an island portion containing the above styrene-based resin. Further, it is more preferable that the extrusion molded article of the present embodiment has a sea-island structure containing a sea portion containing the above propylene-based resin and an island portion containing the above styrene-based resin and styrene-based block copolymer. Particularly preferably, the extrusion molded article of the present embodiment has a sea-island structure containing a sea portion containing the above propylene-based resin and an island portion containing a structure in which the above styrene-based resin is contained in the above styrene-based block copolymer (a structure in which the above styrene-based resin is covered by the above styrene-based block copolymer).

[0060] When the extrusion molded article of the present embodiment has such a sea-island structure, in particular, it becomes an extrusion molded article that is excellently balanced in low molding shrinkage rate, chemical resistance, and impact resistance and has excellent appearance.

[0061] The above-mentioned sea-island structure can be evaluated by cutting the extruded molded article of the present embodiment and observing the fracture surface with a scanning electron microscope. Such a sea-island structure can be formed by using the above-mentioned styrene-based block copolymer and styrene-based resin and a predetermined amount of the above-mentioned propylene-based resin. The presence or absence of the sea-island structure can be determined by immersing the extruded molded article of the present embodiment in tetrahydrofuran (THF) to dissolve polystyrene and the styrene-based block copolymer, and then observing with a scanning electron microscope.

[0062] The use of the extruded molded article of the present embodiment is not particularly limited, and examples include uses in various fields such as household goods, food, agriculture, fisheries, medical, industrial, and construction fields. In particular, body operation switches such as toilets, toilet seats, tanks, cleaners (cleaning nozzles), and cleaning switches; toilet members such as toilet paper holders, floors, and walls; bathroom members such as floors, walls, bathtubs, showers, and faucets; kitchen and washroom members such as sinks, washbasins, faucets, and soap boxes; containers used for storing and transporting food; kitchen members such as tableware, cutting boards, balls, and triangular corners; home appliance members such as refrigerators, washing machines, vacuum cleaners, fans, dryers, air conditioners, telephones, electric kettles, rice cookers, dishwashers, dish dryers, microwave ovens, mixers, VTRs, TVs, clocks, stereos, tape recorders, and OA equipment; stationery members such as fountain pens, mechanical pencils, and ballpoint pens; various medical instruments, various containers, sports goods, daily necessities, building materials, optical instruments, etc.

[0063] Among these, it is particularly preferably used for sanitary members related to plumbing such as bathrooms, toilets, kitchens, and washrooms where chemical resistance is required.

Examples

[0064] Next, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to these examples. The materials used in the following examples and comparative examples are as follows.

[0065] <Propylene-based resin> · "MFR 2 g / 10 min (230 °C, load 2.16 kgf)": "Sun Aroma PL400A", manufactured by Sun Aroma Co., Ltd., homopolypropylene, MFR 3.4 g / 10 min (200 °C, load 5 kgf).

[0066] · "MFR 7.5 g / 10 min (230 °C, load 2.16 kgf)": "Sun Aroma PM600A", manufactured by Sun Aroma Co., Ltd., homopolypropylene, MFR 15 g / 10 min (200 °C, load 5 kgf).

[0067] <Styrene resin> · "MFR 2 g / 10 min (200 °C, load 5 kgf)": HIPS, impact-resistant polystyrene, PSJ 475D, manufactured by PS Japan Co., Ltd.

[0068] · "MFR 4 g / 10 min (200 °C, load 5 kgf)": HIPS, impact-resistant polystyrene, PSJ H8672, manufactured by PS Japan Co., Ltd.

[0069] <Styrene block copolymer> · "MFR 2.9 g / 10 min (200 °C, load 5 kgf), MFR 0.7 g / 10 min (230 °C, load 2.16 kgf)": SEBS, hydrogenated styrene-butadiene block copolymer, Taftec H1051, manufactured by Asahi Kasei Co., Ltd.

[0070] · "MFR 3 g / 10 min (200 °C, load 5 kgf), MFR 2.4 g / 10 min (230 °C, load 2.16 kgf)": SEBS, hydrogenated styrene-butadiene block copolymer, Taftec H1517, manufactured by Asahi Kasei Co., Ltd.

[0071] · "MFR 20 g / 10 min (200 °C, load 5 kgf)": SBS, styrene-butadiene block copolymer, Tufprene 126S, manufactured by Asahi Kasei Co., Ltd.

[0072] Note that the above MFR values are measured based on ISO 1133-1:2011.

[0073] [Examples 1 to 4 and Comparative Examples 1 to 5] Using a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., rotation speed: 200 - 600 rpm, screw diameter: 26 mm, L / D: 48), the components shown in Table 1 were melt-kneaded at 170 - 230 °C so as to be in the parts by mass shown in Table 1. After extrusion, the mixture was cut into a predetermined length to obtain a pelletized resin composition for extrusion molding.

[0074] <mfr> The MFR (g / 10 min) of the obtained resin composition for extrusion molding was measured under the conditions of 200 °C and a load of 5 kgf based on ISO 1133-1:2011. The results are shown in Table 1.

[0075] <Preparation of Test Specimens> Using the obtained resin composition for extrusion molding, after kneading with an extrusion molding machine, it was extruded from a die to form a sheet-like extruded body. Specifically, the resin composition was put into an extruder (co-rotating twin-screw extruder) and kneaded, and then extruded from a T-die through a gear pump and continuously formed by winding it around a cooling roll (three-roll system) as it was. In this way, a sheet-like extruded body with a thickness of 3 mm and a width of 20 cm was obtained.

[0076] For the test specimens for chemical resistance measurement, those obtained by cutting the obtained sheet-like extruded body into pieces with a length of 80 mm and a width of 12 mm (thickness 3 mm) were used.

[0077] <Moldability> The state of the resin composition for extrusion molding discharged from the T-die was observed, and the observation results were classified according to the following evaluation criteria to evaluate the moldability. The results are shown in Table 1.

[0078] ○: The discharge from the T-die is stable and molding is easy. Moreover, the thickness deviation in the width direction of the molded body is small (less than 0.5 mm).

[0079] ×: The thickness deviation in the width direction of the molded body is large (0.5 mm or more) and the practicality is low. Or the discharge from the T-die is unstable and molding is difficult.

[0080] <Chemical Resistance> The obtained test specimens were mounted on a plurality of jigs capable of applying different bending strains (%), and on the test specimens fixed in this way, a mixed liquid containing 90% or more of glyceryl (caprylate / caprate / oleate) was brought into contact as a chemical solution, and when left in a constant temperature bath at 23 ± 2 °C for 48 hours, the minimum value of the bending strain at which cracks occurred was taken as the critical strain (%) to evaluate the chemical resistance.

[0081] As for the jig that applies bending strain (%), jigs with bending strains of 0.3%, 0.45%, 0.6%, 0.9%, 1.2%, and 1.6% were used. For example, when the bending strain was 1.2%, no crack occurred. When a crack occurred when the bending strain was 1.6%, the critical strain was set to 1.2%. When a crack occurred even when the bending strain was 0.3%, the critical strain was set to <0.3%. When no crack occurred even when the bending strain was 1.6%, the critical strain was set to >1.6%. The results are shown in Table 1.

[0082] In this evaluation, when the critical strain is 0.9% or more, it can be said that the chemical resistance is excellent.

[0083] <Scanning Electron Microscope Observation> The obtained test piece was cut in a direction parallel to the MD direction. The cut test piece was immersed in an ultrasonic vibrator filled with normal-temperature tetrahydrofuran (THF) for 30 minutes. Then, the test piece was taken out from the THF and dried at normal temperature for 1 hour in a vacuum dryer. The cross-sectional structure was observed using a scanning electron microscope (manufactured by Hitachi, Ltd., model number: TM3030 Plus Miniscope) (magnification: 2000 times). And when it had a sea-island structure, it was regarded as "having", and when it did not have a sea-island structure, it was regarded as "not having", and the results are shown in Table 1.

[0084]

Table 1

[0085] (Summary) As described above, the resin composition for extrusion molding according to the first aspect includes a styrene block copolymer, a styrene resin other than the styrene block copolymer, and a propylene resin, and has a melt flow rate (200 ° C, load 5 kgf) of less than 5 g / 10 min. The propylene resin is contained in an amount of 35% by mass or more and 65% by mass or less based on 100% by mass in total of the styrene resin and the propylene resin. The melt flow rate (200 ° C, load 5 kgf) of the styrene resin is less than 4 g / 10 min. The ratio of the melt flow rate (200 ° C, load 5 kgf) of the propylene resin to the melt flow rate (200 ° C, load 5 kgf) of the styrene resin is 1.5 or more and 5 or less.

[0086] According to this aspect, an extruded article having good characteristics of both a propylene resin and a styrene resin, excellent balance in low molding shrinkage rate, chemical resistance, and impact resistance, and excellent extrusion moldability can be obtained.

[0087] The second aspect is the resin composition for extrusion molding according to the first aspect, wherein the melt flow rate (230 ° C, load 2.16 kgf) of the propylene resin is 1 g / 10 min or more and 10 g / 10 min or less.

[0088] According to this aspect, an extruded article having excellent balance in low molding shrinkage rate, chemical resistance, and impact resistance, and excellent extrusion moldability can be obtained.

[0089] The third aspect is the resin composition for extrusion molding according to the first or second aspect, wherein the melt flow rate (200 ° C, load 5 kgf) of the styrene resin is 1 g / 10 min or more and 2.5 g / 10 min or less.

[0090] According to this aspect, an extruded article having excellent balance in low molding shrinkage rate, chemical resistance, and impact resistance, and excellent extrusion moldability can be obtained.

[0091] The extruded article according to the fourth aspect includes the resin composition for extrusion molding according to any one of the first to third aspects.

[0092] According to this aspect, it is excellently balanced in terms of low molding shrinkage rate, chemical resistance, and impact resistance.< / mfr> < / hips> < / gpps>

Claims

1. An extrusion molding resin composition comprising a styrene-based block copolymer, a styrene-based resin other than the styrene-based block copolymer, and a propylene-based resin, and having a melt flow rate (at 200 °C, load 5 kgf) of less than 5 g / 10 min, wherein the propylene-based resin is contained in an amount of 35% by mass or more and 65% by mass or less based on 100% by mass in total of the styrene-based resin and the propylene-based resin, the melt flow rate (at 200 °C, load 5 kgf) of the styrene-based resin is less than 4 g / 10 min, and the ratio of the melt flow rate (at 200 °C, load 5 kgf) of the propylene-based resin to the melt flow rate (at 200 °C, load 5 kgf) of the styrene-based resin is 1.5 or more and 5 or less, an extrusion molding resin composition.

2. The melt flow rate (at 230 °C, load 2.16 kgf) of the propylene-based resin is 1 g / 10 min or more and 10 g / 10 min or less, the extrusion molding resin composition according to Claim 1.

3. The melt flow rate (at 200 °C, load 5 kgf) of the styrene-based resin is 1 g / 10 min or more and 2.5 g / 10 min or less, the extrusion molding resin composition according to Claim 1.

4. An extrusion molded article comprising the extrusion molding resin composition according to any one of Claims 1 to 3.

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