Resin composition and molded article thereof

Abstract

Provided are: a resin composition which contains an eggshell powder, has good tensile modulus of elasticity and tensile elongation at break, and also has excellent moldability; a resin composition containing an eggshell powder (A), a polystyrene resin (B), and an additive (C), the ratio of the eggshell powder (A) to the total 100 parts by mass of the eggshell powder (A) and the polystyrene resin (B) being 20 parts by mass or more, the additive (C) containing at least one compound selected from the group consisting of fatty acid amides (c1), sodium aliphatate (c2), and fatty acid esters (c3), the total content of the fatty acid amide (c1), the sodium aliphatate (c2), and the fatty acid ester (c3) is more than 50 mass% with respect to the total mass of the additive (C), and the content of the additive (C) is 10 parts by mass or less with respect to the total 100 parts by mass of the eggshell powder (A) and the polystyrene resin (B).

Description

Technical Field

[0001] The present invention relates to a resin composition and a molded product thereof. Background Art

[0002] In recent years, in order to build a sustainable society, research on resin compositions containing biomass is being conducted. The resin compositions containing biomass are formed by combining materials derived from biomass with thermoplastic resins derived from fossil resources such as petroleum. For example, Patent Document 1 proposes a thermoplastic resin composition, which is formed by mixing biomass powders such as wood powder or bamboo powder as fillers. In addition, from the perspective of waste utilization, research is also being conducted on replacing calcium carbonate powders and the like mixed as inorganic fillers in thermoplastic resin compositions using eggshell powder or shell powder. Such resin compositions containing biomass are being paid attention to as resin compositions with less burden on the environment because the ratio of thermoplastic resins derived from fossil resources is reduced by increasing the ratio of materials derived from biomass.

[0003] However, resin products used for home appliances, automotive interior materials, toys, etc. are usually formed by injection molding, etc. Among them, polystyrene resins are widely used as thermoplastic resins for injection molding due to their excellent transparency, formability and low price. For polystyrene resin compositions that can be used in these various applications, it is also required to replace or reduce the amount of polystyrene resins derived from fossil resources with materials derived from biomass.

[0004] In response to this requirement, the inventors have studied replacing the inorganic filler in the polystyrene resin composition with eggshell powder derived from biomass to prepare a resin composition with a lower environmental burden. The results show that the mechanical strength such as tensile elastic modulus and tensile elongation at break of the polystyrene resin composition containing eggshell powder is easily reduced, and it is difficult to obtain the desired physical properties. In addition, for thermoplastic resins for injection molding, moderate fluidity is also required from the perspective of filling or formability in the mold, but the fluidity of the composition is also easily reduced, and the formability is also easily deteriorated.

[0005] Prior art

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-119048 Summary of the invention

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a resin composition and a molded product thereof, wherein the resin composition contains eggshell powder and has good tensile elastic modulus and tensile elongation at break and is also excellent in moldability.

[0008] In response to the above-mentioned technical problems, the present inventors conducted in-depth research and found that by adding a certain amount of additives containing a specific compound as the main component relative to the total amount of eggshell powder and polystyrene resin, a resin composition with excellent tensile elastic modulus and tensile elongation at break and good formability can be obtained, thereby completing the present invention.

[0009] That is, the present invention has the following aspects.

[0010] [1] A resin composition comprising eggshell powder (A), a polystyrene resin (B), and an additive (C),

[0011] The ratio of the eggshell powder (A) to 100 parts by mass of the total of the eggshell powder (A) and the polystyrene resin (B) is 20 parts by mass or more,

[0012] The above-mentioned additive (C) contains at least one compound selected from fatty amide (c1), sodium fatty acid (c2), and fatty acid ester (c3), and the total content of the above-mentioned fatty amide (c1), the above-mentioned sodium fatty acid (c2) and the above-mentioned fatty acid ester (c3) exceeds 50 mass% relative to the total mass of the above-mentioned additive (C), and the content of the above-mentioned additive (C) is less than 10 mass parts relative to the total of 100 mass parts of the above-mentioned eggshell powder (A) and the above-mentioned polystyrene resin (B).

[0013] [2] The resin composition according to [1], wherein the ratio of the eggshell powder (A) to 100 parts by mass of the total of the eggshell powder (A) and the polystyrene resin (B) is 70 parts by mass or less.

[0014] [3] The resin composition as described in [1] or [2], wherein the MFR (Melt mass-flow rate) of the resin composition under the conditions of 200°C and a load of 5 kg is 4.0 g / 10 min or more.

[0015] [4] The resin composition according to [1] or [2], wherein the MFR of the resin composition under conditions of 220°C and a load of 10 kg is 4.0 g / 10 min or more.

[0016] [5] The resin composition as described in any one of [1] to [3], wherein the polystyrene resin (B) comprises at least one resin selected from a general-purpose polystyrene resin (b1) and an impact-resistant polystyrene resin (b2), and a styrene-butadiene copolymer resin (b3).

[0017] [6] The resin composition described in [1], [2], [4] or [5], wherein the polystyrene resin (B) comprises an acrylonitrile-butadiene-styrene copolymer resin (b4).

[0018] [7] The resin composition according to any one of [1] to [6], wherein the average particle size of the eggshell powder (A) is 3 to 50 μm.

[0019] [8] The resin composition according to any one of [1] to [7], which is used for injection molding.

[0020] [9] A molded article comprising the resin composition as described in any one of [1] to [8].

[0021] According to the present invention, a resin composition containing eggshell powder, having good tensile elastic modulus and tensile elongation at break and excellent moldability and a molded product thereof can be provided. The resin composition contains eggshell powder and has good tensile elastic modulus and tensile elongation at break and excellent moldability. DETAILED DESCRIPTION

[0022] Hereinafter, an embodiment of the present invention is described in detail. The present invention is not limited to the following embodiments and can be implemented by appropriately changing the scope without hindering the effect of the present invention. When a specific description recorded in one embodiment is also applicable to other embodiments, the description is sometimes omitted in other embodiments. In this specification, "X to Y" indicating a numerical range means "above X and below Y".

[0023] [Resin composition]

[0024] The resin composition of the present embodiment is characterized in that: it contains eggshell powder (A), a polystyrene resin (B), and an additive (C), the ratio of the above-mentioned eggshell powder (A) to 100 parts by mass of the total of the above-mentioned eggshell powder (A) and the above-mentioned polystyrene resin (B) is 20 parts by mass or more, the above-mentioned additive (C) contains at least one compound selected from the group consisting of fatty amide (c1), sodium fatty acid (c2), and fatty acid ester (c3), the total content of the above-mentioned fatty amide (c1), the above-mentioned sodium fatty acid (c2), and the above-mentioned fatty acid ester (c3) exceeds 50% by mass relative to the total mass of the above-mentioned additive (C), and the content of the above-mentioned additive (C) is 10 parts by mass or less relative to 100 parts by mass of the total of the above-mentioned eggshell powder (A) and the above-mentioned polystyrene resin (B).

[0025] The resin composition of the present embodiment has good tensile elastic modulus and tensile elongation at break and is also excellent in formability. In addition, owing to containing a certain amount of eggshell powder as a material derived from biomass, the burden on the environment is also less compared with existing polystyrene resin compositions.

[0026] <Eggshell powder (A)>

[0027] The resin composition of the present embodiment contains eggshell powder (A) (hereinafter, sometimes described as "(A) component"). The content of eggshell powder (A) is 20 parts by mass or more relative to 100 parts by mass of the total of eggshell powder (A) and polystyrene resin (B) (hereinafter, sometimes described as "(B) component"). The "eggshell powder (A)" in this specification is obtained by powdering eggshells, and its raw material is not particularly limited, but from the viewpoint of effective utilization of waste, it is preferably composed of chicken eggshells as a raw material.

[0028] In one embodiment, relative to the total of 100 parts by mass of (A) component and (B) component, the ratio of (A) component in the resin composition may be 30 parts by mass or more, 40 parts by mass or more, or 50 parts by mass or more. From the viewpoint of the composite of the obtained resin composition, relative to the total of 100 parts by mass of (A) component and (B) component, the ratio of (A) component in the resin composition is preferably set to 70 parts by mass or less. That is, the ratio of (A) component to the total of 100 parts by mass of (A) component and (B) component may be 20 to 70 parts by mass, 30 to 70 parts by mass, 40 to 70 parts by mass, or 50 to 70 parts by mass. In one embodiment, relative to the total of 100 parts by mass of (A) component and (B) component, the ratio of (A) component may be 20 to 50 parts by mass, or 20 to 55 parts by mass.

[0029] In one embodiment, the average particle size of the eggshell powder (A) is preferably 3 to 50 μm, more preferably 3 to 40 μm, and further preferably 4 to 30 μm. In one embodiment, the average particle size of the eggshell powder (A) may be 10 to 50 μm, 10 to 30 μm, or 3 to 15 μm. When a powder having a finer average particle size is used as the eggshell powder (A), the viscosity of the obtained resin composition tends to increase, and the fluidity during molding decreases. In addition, the dispersibility of the eggshell powder (A) in the resin composition tends to decrease. On the other hand, if the average particle size is too large, it is difficult to obtain a molded product with the required strength or flexibility. In particular, when an eggshell powder (A) having an average particle size greater than 50 μm is used as the eggshell powder (A), the resin tends to break easily, and it is difficult to obtain the required tensile elongation at break. In addition, the average particle size of the eggshell powder (A) can be measured using a particle size distribution measuring device according to the "sieving method".

[0030] In one embodiment, the density (g / cm 3 ) is preferably 2.0 to 3.0 g / cm 3, more preferably 2.0 to 2.8 g / cm 3 , particularly preferably 2.3 to 2.7 g / cm 3 .

[0031] In one embodiment, the ratio of the eggshell powder (A) in the resin composition may be 10 to 70% by mass, or 30 to 60% by mass, relative to the total mass of the resin composition.

[0032] The eggshell powder (A) can be prepared by a conventionally known manufacturing method. For example, the eggshell can be crushed by a known method and then classified to obtain an eggshell powder (A) having a desired average particle size. Specifically, after removing the eggshell membrane from the eggshell, the eggshell is dried. Thereafter, the eggshell is crushed using a pulverizer or the like to obtain a powder of the eggshell. Thereafter, the eggshell is classified using a sieve having an appropriate mesh size to obtain the eggshell powder (A).

[0033] In addition, commercially available eggshell powder (A) may be used, for example, Green Techno21 (Co., Ltd.), trade name: GT-26, Kewpie Egg (Co., Ltd.), trade name: Calhope (registered trademark), etc. may be mentioned.

[0034] In one embodiment, the resin composition may also contain inorganic fillers other than component (A). As inorganic fillers other than component (A), for example, inorganic fillers derived from minerals such as calcium carbonate, talc, and zeolite; inorganic fillers derived from biominerals other than eggshell powder, etc. In addition, "biominerals" refer to minerals produced by organisms, such as pearls, shells, eggshells, bones, and the exoskeleton of crustaceans. When component (A) and the aforementioned inorganic filler are used in combination, it is preferred that the total amount of component (A) and the aforementioned inorganic filler is adjusted to within a range of no more than 70 parts by mass relative to a total of 100 parts by mass of component (A) and component (B). In addition, from the perspective of easily taking into account tensile elastic modulus, tensile elongation at break, and formability, it is also possible to include only eggshell powder (A) as an inorganic filler.

[0035] <Polystyrene resin (B)>

[0036] The resin composition of the present embodiment includes a polystyrene resin (B). Relative to a total of 100 parts by mass of the component (A) and the component (B), the ratio of the polystyrene resin (B) is 80 parts by mass or less. In one embodiment, the ratio of the component (B) may be 30 to 80 parts by mass, 60 to 80 parts by mass, or 50 to 80 parts by mass. From the perspective of making a resin composition with less component (B), the ratio of the component (B) may also be 30 to 50 parts by mass relative to a total of 100 parts by mass of the component (A) and the component (B).

[0037] In this specification, the so-called "polystyrene resin (B)" refers to a polymer containing monomer units derived from an aromatic vinyl compound. The polystyrene resin (B) of this embodiment may include: a polymer of an aromatic vinyl compound; a copolymer of a compound copolymerizable with an aromatic vinyl compound and an aromatic vinyl compound; or a polymer obtained by polymerizing these in the presence of a rubber polymer.

[0038] Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, ethylstyrene, p-tert-butylstyrene, etc. These may be used alone or in combination of two or more. Among them, styrene is preferably included.

[0039] Examples of the compound copolymerizable with the aromatic vinyl compound include methacrylates such as methyl methacrylate and ethyl methacrylate, unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile, and acid anhydrides such as maleic anhydride. These may be used alone or in combination of two or more.

[0040] The mass ratio of the copolymerizable compound is preferably 20 mass % or less, more preferably 15 mass % or less, relative to the total amount (100 mass %) of the aromatic vinyl compound and the copolymerizable compound.

[0041] Examples of the rubber polymer include conjugated diene rubber, copolymers of conjugated diene and aromatic vinyl compounds, ethylene-propylene copolymer rubbers, etc. More specifically, examples include polybutadiene, styrene-butadiene random copolymers, styrene-butadiene block copolymers, and polymers obtained by hydrogenating part or all of these.

[0042] In one embodiment, the weight average molecular weight (Mw) of the polystyrene resin (B) is preferably 10,000 to 500,000, and more preferably 100,000 to 300,000. If the Mw of the polystyrene resin (B) is within the above range, the fluidity tends to become good. In addition, the Mw of the polystyrene resin (B) refers to a value calculated by GPC (gel permeation chromatography) in terms of polystyrene conversion. In addition, when the polystyrene resin (B) is a mixture, the above Mw refers to a value calculated by measuring the mixture using GPC.

[0043] In one embodiment, the polystyrene resin (B) preferably comprises at least one resin selected from general-purpose polystyrene resin (b1) and impact-resistant polystyrene (b2), and styrene-butadiene copolymer resin (b3). From the viewpoint of easily achieving a balance between tensile elastic modulus and tensile elongation at break, general-purpose polystyrene resin (b1) and styrene-butadiene copolymer resin (b3) may be combined. From the viewpoint of obtaining a resin composition having a better tensile elastic modulus, impact-resistant polystyrene (b2) and styrene-butadiene copolymer resin (b3) may also be combined.

[0044] In one embodiment, from the viewpoint of easily obtaining a resin composition having a better tensile elastic modulus and impact strength (especially impact strength), the polystyrene resin (B) may also contain a polymer comprising a monomer unit derived from the above aromatic vinyl compound, a monomer unit derived from the above unsaturated nitrile compound, and the above rubber polymer. As such a polymer, a copolymer of acrylonitrile, styrene and conjugated diene rubber is preferred, and an acrylonitrile-styrene-butadiene copolymer (b4) is more preferred.

[0045] (General-purpose polystyrene resin (b1))

[0046] General-purpose polystyrene resin (b1) (hereinafter, sometimes also described as "component (b1)") is a homopolymer of styrene and is a resin represented by "GPPS". By making component (B) contain component (b1), the tensile elastic modulus tends to become good. In one embodiment, from the viewpoint of fluidity, the mass average molecular weight (Mw) of component (b1) may be 10,000 to 500,000, or 100,000 to 300,000. The Mw of component (b1) refers to the value calculated by GPC (gel permeation chromatography) in terms of polystyrene conversion.

[0047] When the component (B) includes the component (b1), from the viewpoint of tensile elastic modulus, the ratio of the component (b1) in the component (B) is preferably 20 to 95% by mass, more preferably 30 to 80% by mass, relative to the total mass of the component (B). In addition, the ratio of the component (b1) in the resin composition may be 10 to 80% by mass, or 10 to 60% by mass, relative to the total mass of the resin composition.

[0048] (High-impact polystyrene (b2))

[0049] The high-impact polystyrene (b2) (hereinafter, sometimes also described as "component (b2)") is a graft polymer obtained by graft polymerization of a styrene monomer and a rubber polymer, and is a resin represented by "HIPS". By making the (B) component contain the (b2) component, the impact strength (impact resistance) of the obtained molded product is easily improved. In one embodiment, from the viewpoint of fluidity, the mass average molecular weight (Mw) of the (b2) component may be 100,000 to 250,000, or 130,000 to 200,000. The Mw of the (b2) component refers to the value calculated by GPC (gel permeation chromatography) in terms of polystyrene conversion. In one embodiment, the ratio of the rubber polymer in the (b2) component (the ratio of the rubber component) is preferably 1 to 15% by mass, more preferably 2 to 14% by mass, and further preferably 3 to 13% by mass, relative to the total mass of the (b2) component. The ratio of the rubber polymer in the component (b2) (ratio of the rubber component) can be 1 to 10% by mass, 2 to 8% by mass, or 3 to 6% by mass relative to the total mass of the component (b2). The ratio of the rubber component in the component (b2) can be calculated from the amount added when preparing the component (b2), or can be measured by the same method as the "amount of conjugated diene" described below.

[0050] When component (B) includes component (b2), from the viewpoint of fluidity, the ratio of component (b2) in component (B) is preferably 10 to 90% by mass, more preferably 50 to 85% by mass, relative to the total mass of component (B). In addition, the ratio of component (b2) in the resin composition may be 5 to 75% by mass, or 10 to 60% by mass, relative to the total mass of the resin composition.

[0051] (Styrene-butadiene copolymer resin (b3))

[0052] Styrene-butadiene copolymer resin (b3) (hereinafter, sometimes also recorded as "(b3) component") is a copolymer resin formed by polymerizing a monomer mixture containing styrene and butadiene. As (b3) component, for example, block copolymers such as styrene-butadiene (SB), styrene-butadiene-butylene (SBB), styrene-butadiene-isoprene (SBI), styrene-butadiene-styrene (SBS), styrene-butadiene-butylene-styrene (SBBS), and styrene-butadiene-isoprene-styrene (SBIS) and block copolymers formed by hydrogenating these, etc. can be cited. These can be used alone or in combination of two or more. Among them, from the viewpoint of being easier to improve the brittleness caused by the high filling of the filler containing eggshell powder, (b3) component preferably includes styrene-butadiene (SB) copolymer.

[0053] In one embodiment, the mass average molecular weight (Mw) of the (b3) component is preferably 100,000 to 200,000, and more preferably 120,000 to 180,000. If the Mw of the (b3) component is within the above range, the compatibility with the (b1) component and / or the (b2) component is easily improved. In addition, the Mw of the (b3) component refers to the value calculated by GPC (gel permeation chromatography) in terms of polystyrene.

[0054] In one embodiment, from the viewpoint of improving brittleness, the ratio of the component (b3) in the component (B) is preferably 5 to 80% by mass, more preferably 20 to 70% by mass, relative to the total mass of the component (B). In addition, the ratio of the component (b3) in the resin composition may be 5 to 30% by mass, or 10 to 25% by mass, relative to the total mass of the resin composition.

[0055] In one embodiment, from the viewpoint of more easily adjusting the tensile modulus of the resin composition, the amount of conjugated diene in the component (b3) is preferably 5 to 40% by mass, more preferably 6 to 30% by mass, and particularly preferably 8 to 28% by mass, relative to the total mass of the component (b3). The so-called "amount of conjugated diene" refers to the amount of butadiene contained in the component (b3). The amount of conjugated diene can be a value calculated based on the amount of butadiene added when preparing the component (b3), or a value measured by potentiometric titration using iodine monochloride, potassium iodide, and sodium thiosulfate standard solution.

[0056] (Acrylonitrile-butadiene-styrene copolymer (b4))

[0057] Examples of the acrylonitrile-butadiene-styrene copolymer (b4) include: a mixture of a copolymer of styrene and acrylonitrile and polybutadiene; a graft polymer obtained by grafting styrene and acrylonitrile with polybutadiene; a product obtained by melt-mixing the above copolymer and the above graft polymer; a product obtained by melt-mixing a copolymer of butadiene and acrylonitrile and the above copolymer, etc., but the present invention is not limited to these.

[0058] In one embodiment, from the viewpoint of improving brittleness, the ratio of the component (b4) in the component (B) may be 30 to 100% by mass, 40 to 100% by mass, or 50 to 90% by mass, relative to the total mass of the component (B). In addition, the ratio of the component (b4) in the resin composition may be 30 to 80% by mass, or 40 to 80% by mass, relative to the total mass of the resin composition.

[0059] In one embodiment, from the viewpoint of making it easier to adjust the tensile modulus of the resin composition, the amount of conjugated diene in the component (b4) is preferably 5 to 40% by mass, more preferably 7 to 30% by mass, and particularly preferably 10 to 25% by mass, relative to the total mass of the component (b4). The "amount of conjugated diene" is the amount of butadiene contained in the component (b4), which, like the component (b3), can be a value calculated based on the amount of butadiene added, or a value measured by potentiometric titration using iodine monochloride, potassium iodide, and sodium thiosulfate standard solutions.

[0060] In one embodiment, when component (B) includes at least one resin selected from component (b1) and component (b2) and component (b3), the total amount of component (b1), component (b2), and component (b3) in component (B) may be 50 to 100% by mass, or 60 to 100% by mass, relative to the total mass of component (B). If the total amount of components (b1) to (b3) in component (B) is within the above range, a resin composition having good tensile elastic modulus and fluidity can be easily obtained.

[0061] (B) component may also include components (other components) other than components (b1) to (b4). As other components, for example, styrene-based thermoplastic elastomers other than the above-mentioned components (b3) and (b4) (for example, copolymers such as styrene-isoprene (SI), styrene-isoprene-styrene (SIS), and copolymers obtained by hydrogenating these, etc.) may be mentioned. These may be used alone or in combination of two or more. When component (B) includes other components, it is preferably set to 30% by mass or less relative to the total mass of component (B).

[0062] <Additives (C)>

[0063] The resin composition of the present embodiment includes an additive (C). The additive (C) includes at least one compound selected from fatty amide (c1), sodium fatty acid (c2), and fatty acid ester (c3), and the total content of the above-mentioned compound (c1), (c2), and (c3) exceeds 50% by mass relative to the total mass of the additive (C). In the present embodiment, the additive (C) includes the above-mentioned compound as a main component.

[0064] The content of the additive (C) in the resin composition of the present embodiment is 10 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B). By combining such additive (C) with the components (A) and (B), a resin composition having good tensile elongation at break and tensile elastic modulus and excellent formability can be prepared.

[0065] In one embodiment, the content of the additive (C) may be 9 parts by mass or less, 8 parts by mass or less, or 7 parts by mass or less, relative to 100 parts by mass of the total of the components (A) and (B). The lower limit of the content of the additive (C) is not particularly limited as long as it has the effect of the present invention, and may be 0.5 parts by mass or more, or 1 part by mass or more. That is, the content of the additive (C) may be 0.5 to 10 parts by mass, 0.5 to 9 parts by mass, 0.5 to 8 parts by mass, 1 to 8 parts by mass, or 1 to 6 parts by mass, relative to 100 parts by mass of the total of the components (A) and (B).

[0066] (Fat amide (c1))

[0067] In the present embodiment, the additive (C) may include a fatty amide (c1) (hereinafter, sometimes also described as "compound (c1)"). The fatty amide (c1) is a compound having an amide group represented by "R1-C(=O)-N-" in its structure. In addition, "fatty amide" includes primary amides, secondary amides, tertiary amides, and amides having two or more nitrogen atoms in one molecule. On the other hand, the fatty amide (c1) in the present embodiment does not include polymers such as aliphatic polyamides represented by nylon-6.

[0068] The above R1 is a hydrocarbon group which may have a substituent. The so-called "may have a substituent" means that one or more hydrogen atoms in the hydrocarbon group may be replaced by a substituent. R1 is preferably an alkyl group having 2 or more carbon atoms which may have a substituent or an alkenyl group which may have a substituent. Such fatty amide (c1) is not particularly limited as long as it has the effect of the present invention. From the viewpoint of compatibility with component (B), it is preferably a higher fatty acid amide in which R1 is an alkyl group having 10 or more carbon atoms which may have a substituent or an alkenyl group which may have a substituent. Specifically, examples include: saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide; unsaturated fatty acid monoamides such as oleic acid amide and erucic acid amide; substituted amides such as N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide; saturated fatty acid bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, N,N'-distearyl adipamide; unsaturated fatty acid bisamides such as ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, etc. These may be used alone or in combination of two or more. Among them, the compound (c1) preferably contains a saturated fatty acid bisamide having 10 or more carbon atoms, from the viewpoint of better extrusion with the resin and easier improvement of moldability.

[0069] (Sodium fatty acid (C2))

[0070] In the present embodiment, the additive (C) may include sodium fatty acid (c2). Sodium fatty acid (c2) (hereinafter, sometimes also recorded as "compound (c2)") is a compound represented by "R2-C(=O)-O-Na", and as for R2, the same group as R1 can be exemplified, preferably an alkyl group having a carbon number of 2 or more, which may have a substituent, or an alkenyl group having a substituent. As such sodium fatty acid (c2), there is no particular limitation as long as it has the effect of the present invention. In one embodiment, from the viewpoint of easily obtaining a resin composition that is easily compatible with component (B) and has a better tensile elongation at break, it is preferred that R2 is a sodium salt of a higher fatty acid having a carbon number of 10 or more, which may have an alkyl group having a substituent, or an alkenyl group having a substituent. Specifically, sodium salts of higher fatty acids having a carbon number of 10 to 20, such as sodium laurate, sodium myristic acid, sodium palmitate, sodium oleate, and sodium stearate, can be cited. These can be used alone or in combination of two or more. That is, the fatty acid sodium (c2) may be a mixture of the aforementioned higher fatty acid sodium salts having 10 to 20 carbon atoms.

[0071] (Fatty acid ester (c3))

[0072] In the present embodiment, the additive (C) may include a fatty acid ester (c3). The fatty acid ester (c3) (hereinafter, sometimes also recorded as "compound (c3)") is an ester containing a fatty acid group represented by "R3-C(=O)O-" in the structure. In one embodiment, the fatty acid ester (c3) is preferably a higher fatty acid ester obtained by the reaction of a higher fatty acid having 10 or more carbon atoms with a polyol. The higher fatty acid is preferably an alkyl or alkenyl group having 10 or more carbon atoms which may have a substituent. In addition, as polyols, divalent to hexavalent polyols such as ethylene glycol, glycerol, 1,2,4-butanetriol, diglycerol, pentaerythritol, sorbitol, erythritol, and hexanetriol can be cited.

[0073] In a preferred embodiment, the higher fatty acid ester may include glycerol fatty acid ester. As glycerol fatty acid ester, for example, lauric acid monoglyceride, lauric acid diglyceride, lauric acid triglyceride, palmitic acid monoglyceride, palmitic acid diglyceride, palmitic acid triglyceride, stearic acid monoglyceride, stearic acid diglyceride, stearic acid triglyceride, stearic acid tetraglyceride, hydroxystearic acid monoglyceride, hydroxystearic acid diglyceride, hydroxystearic acid triglyceride, hydroxystearic acid tetraglyceride, etc. These can be used alone or in combination of two or more. Among them, from the perspective of easily obtaining the compatibility of eggshell powder and resin components that is easier to improve and the resin composition with better tensile elongation at break, it is preferred to include hydroxystearic acid glyceride.

[0074] In one embodiment, the additive (C) preferably contains a sodium fatty acid (c2) from the viewpoint of easily obtaining a better tensile elongation at break.

[0075] In the resin composition of the present embodiment, the total content of the compounds (c1) to (c3) in the additive (C) may exceed 50% by mass, may exceed 50% by mass and may be 100% by mass or less, may be 55 to 100% by mass, may be 60 to 100% by mass, or may be 65 to 100% by mass, relative to the total mass of the additive (C).

[0076] In one embodiment, the additive (C) may also contain other additives other than the aforementioned compounds (c1) to (c3). Other additives include, for example, ultraviolet absorbers, light stabilizers, antioxidants, lubricants, plasticizers, colorants, antistatic agents, flame retardants, mold release agents, mineral oils and other compounds; reinforcing fibers such as glass fibers, carbon fibers, and aromatic polyamide fibers. These may be used alone or in combination of two or more.

[0077] (Plasticizer)

[0078] In one embodiment, the additive (C) may further include a plasticizer. By combining at least one selected from compounds (c1), (c2), and (c3) with a plasticizer, it is easy to obtain a resin composition in which mechanical properties such as tensile elastic modulus and tensile elongation at break and formability are maintained within a good range and a static friction coefficient is low. The wear resistance of this resin composition is also easy to become good. Here, the so-called "wear resistance" may refer to a molded product having a fitting portion that is not easy to wear when repeatedly fitting.

[0079] Examples of the plasticizer include paraffin-based or naphthenic process oils, liquid paraffin or other paraffins, waxes, synthetic polymer plasticizers such as silicone oil or silicone rubber, ester plasticizers such as phthalic acid, adipic acid, sebacic acid or phosphoric acid, etc. Among them, it is preferred to include a synthetic polymer plasticizer, especially at least one plasticizer selected from silicone oil and silicone rubber.

[0080] (i) Silicone oil

[0081] The silicone oil is not particularly limited, and known silicone oils can be used. In one embodiment, as the silicone oil, for example, dimethylpolysiloxane, methylphenylsiloxane, methylhydrogenpolysiloxane, and modified forms thereof can be cited. These can be used alone or in combination of two or more. Among them, from the viewpoint of easily obtaining a resin composition with better wear resistance, dimethylpolysiloxane is preferably included. In a preferred embodiment, as the dimethylpolysiloxane, a kinetic viscosity of 100 to 500 mm at 25°C can be used. 2 The kinematic viscosity can be measured, for example, at a test temperature of 37.8° C. or 40° C. using a Cannon-Fenske viscometer in accordance with “5. Kinematic viscosity test method” of JIS K 2283:2000.

[0082] (ii) Silicone rubber

[0083] Silicone rubber is a rubber containing polyorganosiloxane rubber. Silicone rubber is not particularly limited, for example, polyorganosiloxane rubber or silicone / acrylic composite rubber formed by compounding polyorganosiloxane with poly(meth) alkyl acrylate rubber can be used. In addition, the so-called "silicone / acrylic composite rubber" is a composite rubber obtained by polymerizing various monomers in stages when polymerizing two or more monomers constituting the above-mentioned rubber. Among them, from the perspective of easily obtaining a resin composition with better wear resistance, silicone / acrylic composite rubber may also be included.

[0084] When the additive (C) includes a plasticizer, the content of the plasticizer in the additive (C) can be appropriately adjusted to a range of 50% by mass or less relative to the total mass of the additive (C). In one embodiment, the content of the plasticizer in the additive (C) can be 0.3 to 3.0 parts by mass, 0.3 to 2.5 parts by mass, 0.3 to 2.0 parts by mass, or 0.3 to 1.5 parts by mass relative to a total of 100 parts by mass of the components (A) and (B). If the content of the plasticizer is within the above range, the plasticizer is not easy to ooze out, and the wear resistance is also easy to become good.

[0085] The additive (C) may contain other components besides the aforementioned plasticizer, and may further contain, for example, an ultraviolet absorber, a light stabilizer, an antioxidant, a lubricant, and the like.

[0086] Examples of the ultraviolet absorber include 2-(5'-methyl-2'-hydroxyphenyl)benzotriazole, 2-(5'-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-5'-methyl-2'-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole, and 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole. Benzotriazole-based ultraviolet absorbers such as benzotriazole (2-(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol) and benzotriazole (2-(3',5'-di-tert-amyl-2'-hydroxyphenyl)benzotriazole, 2-[3'-(3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methyl-2'-hydroxyphenyl]benzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol]; 2-ethoxy-2'-ethyloxalyl dianilide, 2-ethoxy -5-tert-butyl-2'-ethyl oxalyl dianilide, 2-ethoxy-4'-isodecylphenyl oxalyl dianilide and other oxalyl anilide ultraviolet absorbers; 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone Benzophenone-based UV absorbers such as benzophenone, ...

[0087] Examples of the light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidinyl succinate polycondensate, poly[[6,(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2, 4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-hexamethylene-[(2,2,6,6-tetramethyl-4-piperidinyl)imino]], 1-[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, etc. These may be used alone or in combination of two or more.

[0088] Examples of the antioxidant include phenolic antioxidants such as triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2-thiobis(4-methyl-6-tert-butylphenol) and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; and ditridecyl-3,3'-thiodipropionate, dilauryl-3,3'-thiodipropionate and ditetradecyl-3,3'-thiodipropionate. , distearyl-3,3'-thiodipropionate, dioctyl-3,3'-thiodipropionate and other sulfur-based antioxidants; tris(nonylphenyl) phosphite, 4,4'-butylene-bis(3-methyl-6-tert-butylphenyl di-tridecyl) phosphite, (tridecyl) pentaerythritol diphosphite, bis(octadecyl) pentaerythritol diphosphite, bis(di-tert-butylphenyl) pentaerythritol diphosphite, bis(di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, dinonylphenyl octyl phosphite, tetrakis(2,4-di-tert-butylphenyl) 1,4-phenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4'-biphenylene diphosphite, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene and other phosphorus-based antioxidants, etc. These may be used alone or in combination of two or more.

[0089] The ratio of other additives in the additive (C) except the aforementioned plasticizer can also be appropriately adjusted to a range of 50% by mass or less relative to the gross mass of the additive (C). In one embodiment, relative to the gross mass of the additive (C), it is preferably 40% by mass or less, more preferably 30% by mass or less. In addition, in the resin composition of the present embodiment comprising a certain amount of eggshell powder, from the viewpoint of maintaining physical properties such as tensile elongation at break within a good range, it is also possible to only include compounds (c1) to (c3) as the additive (C).

[0090] <Other thermoplastic resins>

[0091] The resin composition of the present embodiment may contain a thermoplastic resin (other thermoplastic resin) other than the polystyrene resin (B), but from the viewpoint of obtaining a resin composition with a low resin content, it is preferred that the resin composition contain no other thermoplastic resin.

[0092] <Characteristics of resin composition>

[0093] In one embodiment, the MFR of the resin composition under 200°C and 5kg load conditions is preferably 4.0g / 10min or more. If the MFR (200°C, 5kg load) of the resin composition is 4.0g / 10min or more, the moldability tends to become better. The MFR (200°C, 5kg load) of the resin composition may be 4.5g / 10min or more, 5.0g / 10min or more, 6.0g / 10min or more, or 10.0g / 10min or more. In addition, the MFR of the resin composition may be measured according to the standard of JIS K7210-2:2014 (ISO 133-2:2011). In addition, when at least one resin selected from the components (b1) and (b2), and the component (b3) are included as the component (B), it is easy to obtain a resin composition having an MFR (200°C, 5kg load) of 4.0g / 10min or more.

[0094] In one embodiment, the MFR of the resin composition under the conditions of 220°C and 10kg load may be 4.0g / 10min or more, 4.5g / 10min or more, 5.0g / 10min or more, 6.0g / 10min or more, or 10.0g / 10min or more. In addition, the MFR (220°C, 10kg load) of the resin composition may also be measured according to the standard of JIS K 7210-2:2014 (ISO 133-2:2011). When the component (b4) is included as the component (B), a resin composition having an MFR (220°C, 10kg load) of 4.0g / 10min or more is easily obtained.

[0095] In one embodiment, the tensile modulus of the resin composition measured according to ASTM-D638 may be 1,000 MPa or more, 1,200 MPa or more, or 1,500 MPa or more. In addition, the upper limit of the tensile modulus is preferably less than 1,800 MPa. That is, the tensile modulus of the resin composition is preferably 1,000 MPa or more and less than 1,800 MPa. In addition, the tensile elongation at break of the resin composition measured according to ASTM-D638 may be 15% or more, 20% or more, or 50% or more. The resin composition of this embodiment contains a certain amount of eggshell powder (A) and has good tensile modulus and tensile elongation at break. In addition, the formability is also good.

[0096] The mechanical strength such as tensile elastic modulus and tensile elongation at break of a resin composition containing eggshell powder is easily reduced. The present inventors have studied the reason for this and found that the adhesion between the eggshell powder and the resin component is low, so it is difficult to obtain the desired tensile properties. The present inventors have further conducted in-depth research and surprisingly found that by adding a certain amount of an additive (C) containing specific compounds (c1) to (c3) as the main component, the adhesion between the eggshell powder and the resin component is easily improved, and as a result, the tensile elongation at break of the obtained resin composition is improved.

[0097] [Method for producing resin composition]

[0098] The resin composition of the present embodiment can be manufactured using eggshell powder (A), polystyrene resin (B), additives (C), and other components used as needed, for example, by melt-kneading these. Specifically, components (A) to (C) are respectively put into a twin-screw extruder, melt-kneaded at a temperature of 200 to 250° C., and then extruded into a linear shape, thereby preparing a granular resin composition.

[0099] [use]

[0100] As mentioned above, the resin combination of the present embodiment has good tensile elastic modulus and tensile elongation at break, and formability is also excellent. Therefore, it is suitable as injection molding resin combination. In addition, of course, the purposes of the resin combination of the present embodiment is not limited to injection molding purposes.

[0101] [Molding products]

[0102] The molded product of the present embodiment comprises the aforementioned resin composition. The molded product of the present embodiment is preferably obtained by injection molding the resin composition of the present embodiment. The tensile elastic modulus and tensile elongation at break of the molded product of the present embodiment are excellent. In addition, the molded product of the present embodiment is a molded product with a small environmental load because it comprises a certain amount of eggshell powder. The molded product of the present embodiment can be applied to purposes such as stationery, furniture, building materials, tableware, containers, gardening materials, toys, etc.

[0103] Example

[0104] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following description.

[0105] [Preparation of eggshell powder (A-1)]

[0106] After washing the eggshells with water, put them into a hot air dryer for drying. Put the dried eggshells into a stirring and separation tank, apply high-pressure water and stir them to separate and remove the egg membrane inside the eggshells. Thereafter, put the eggshells with the egg membrane separated and removed into a hot air dryer again and dry them at 90-120°C for 6 hours. Use a grinder to grind the dried eggshells to obtain eggshell powder (A-1). The density of the obtained eggshell powder (A-1) was measured using a densitometer (manufactured by Shimadzu Corporation, product name "Dry Automatic Densitometer AccuPyc II 1340"), and the result was 2.6 g / cm 3 Furthermore, the obtained powder was classified to obtain an eggshell powder (A-1) having an average particle size of 10 μm.

[0107] [Production of polystyrene resin (B)]

[0108] <Manufacturing of general-purpose polystyrene resin (b1-1)>

[0109] 70.4 kg of pure water and 300 g of tricalcium phosphate were added to a polymerization tank with an internal volume of 200 L and stirred. Subsequently, 80.0 kg of styrene and 267.2 g of benzoyl peroxide were added and sealed, and reacted at 100° C. for 6 hours. After the reaction was completed, the reactant was cooled, neutralized, dehydrated, and dried to obtain a homopolymer of polystyrene (GPPS) (b1-1). The Mw of the obtained component (b1-1) was measured by GPC under the following conditions, and the result was 167,000.

[0110] <GPC measurement conditions>

[0111] Device: Made by Shodex (Co., Ltd.), product name "Shodex SYSTEM-21"

[0112] Column: PLgel MIXED-B

[0113] Measuring temperature: 40℃

[0114] Solvent: Tetrahydrofuran

[0115] Flow rate: 1.0mL / min

[0116] Detection method: RI

[0117] Sample concentration: 0.2 mass%

[0118] Injection volume: 100 μL

[0119] Calibration curve: Standard polystyrene (manufactured by Polymer Laboratories)

[0120] <Production of high-impact polystyrene resin (b2-1)>

[0121] Low-cis polybutadiene rubber (manufactured by Asahi Kasei (Co., Ltd.), trade name "Diene 55AS") was used as a rubber polymer, and the rubber polymer (5.3% by mass relative to the total mass of the polymerization raw material) and styrene were dissolved in ethylbenzene (5% by mass relative to the total mass of the polymerization raw material) as a solvent to prepare a polymerization raw material. In addition, 0.1 parts by mass of an antioxidant for the rubber polymer (manufactured by Ciba-Geigy (Co., Ltd.) of Japan, trade name "Irganox (registered trademark) 1076") was added to the above-mentioned polymerization raw material. The polymerization raw material was supplied at 12.5 kg / hr to a 14L jacketed reactor (R-01) equipped with an anchor-type stirring blade with a blade diameter of 0.285 m. The reaction temperature was 140°C and the rotation speed was 2.17 sec. -1 Stirring to polymerize, thereby obtaining a polymer liquid. The obtained polymer liquid has a polymerization rate of 25%. The polymer liquid is introduced into two jacketed piston flow reactors with an internal volume of 21 L arranged in series. In the first piston flow reactor (R-02), the jacket temperature is adjusted in such a way that the reaction temperature becomes 120 to 140°C in the flow direction of the polymer liquid. In the second piston flow reactor (R-03), the jacket temperature is adjusted in such a way that the reaction temperature has a gradient of 130 to 160°C in the flow direction of the polymer liquid. The polymer rate at the outlet of R-02 is 50%, and the polymer rate at the outlet of R-03 is 70%. Here, the polymer rate is a value calculated according to the following formula (1).

[0122] Polymerization rate (%) = [(amount of polymer produced) / {(amount of monomer added) + (amount of solvent)}] × 100 (1)

[0123] After the obtained polymer solution is heated to 230°C, it is sent to a devolatilization tank with a vacuum degree of 5 torr to separate and recover the unreacted monomer and solvent. Thereafter, the reactant is extracted from the devolatilization tank by a gear pump, and after being made into strands through a template, it is made into pellets through a water tank to obtain an impact-resistant polystyrene resin (b2-1). The rubber component content of the obtained component (b2-1) is 4.8% by mass. In addition, the Mw of the component (b2-1) measured under the same conditions as the component (b1-1) is 210,000.

[0124] <Production of styrene-butadiene copolymer resin (b3-1)>

[0125] Prepare a block copolymer resin of styrene-butadiene as component (b3-1). First, add 500.0 kg of cyclohexane and 75.0 g of tetrahydrofuran (THF) to a reaction container, add 1,000 mL of a 10% by mass cyclohexane solution of n-butyl lithium as a polymerization initiator solution, and maintain at 30°C. Thereafter, add 20.0 kg of styrene to anion polymerize styrene. At this time, the internal temperature rises to 35°C. After the styrene is completely consumed, 56 kg of 1,3-butadiene and 64 kg of styrene are added at the same time. After the styrene and 1,3-butadiene are completely consumed, the internal temperature of the reaction system is lowered to 75°C, and 60.0 kg of styrene is added at one time to terminate the polymerization. Finally, all the active ends of the polymerization are deactivated with water to obtain a polymerization solution of a styrene-butadiene copolymer having a polystyrene block and a tapered block of styrene and butadiene. The polymerized liquid was devolatilized to obtain pelletized block copolymer resin (b3-1) using an extruder. The amount of conjugated diene in the obtained component (b3-1) calculated from the amount of monomer added was 28% by mass.

[0126] <Acrylonitrile-butadiene-styrene copolymer resin (b4-1)>

[0127] As the component (b4-1), the following were used.

[0128] Component (b4-1): acrylonitrile-butadiene-styrene copolymer resin (manufactured by DENKA Corporation, product name "DENKA ABS GR-3000").

[0129] [Additives (C)]

[0130] The following were used as additive (C).

[0131] Compound (c1): ethylene bisstearic acid amide (manufactured by Kao Corporation, product name “KAO WAX EB-FF”).

[0132] Compound (c2): manufactured by MIYOSHIOIL Co., Ltd., product name "Tankaru MH" (a mixture of sodium fatty acids having a mass ratio of lauric acid: myristic acid: palmitic acid: stearic acid: oleic acid = 3:2:40:15:30).

[0133] Compound (c3): 1,2-hydroxystearate triglyceride (manufactured by Dainichi Chemical Industries, Ltd., product name “OHG”).

[0134] <Other additives>

[0135] Plasticizer 1: Silicone oil (dimethyl polysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., product name "KF-96350CS", kinematic viscosity (25°C): 350 mm 2 / s).

[0136] Plasticizer 2: Silicone / acrylic composite rubber (manufactured by Mitsubishi Chemical Co., Ltd., product name “Metablen (registered trademark) SX-005”).

[0137] Zinc stearate: manufactured by Nitto Kasei Kogyo Co., Ltd., product name “Zn-St”.

[0138] Polyethylene wax: manufactured by Mitsui Chemicals, Inc., product name “EXEREX (registered trademark) T”.

[0139] Stearic acid: manufactured by NOF Corporation, product name “STEARIC ACID CHERRY”.

[0140] [Example 1]

[0141] 30 parts by mass of component (b1-1) and 20 parts by mass of component (b2-1) are added as polystyrene resin (B), and 50 parts by mass of eggshell powder (A-1) (average particle size 10 μm) are added. After adding 1 part by mass of compound (c1) relative to 100 parts by mass of the total of components (A) and (B), melt-kneading is performed at 200°C and 350 rpm using a twin-screw extruder (manufactured by Toshiba Machine (Co., Ltd.), product name "TEM35-B"), and then extruded into a linear shape at a discharge rate of 20 kg / hr to obtain a granular resin composition. The MFR of the obtained particles was measured under the following conditions, and the result was 6.7 g / 10 min. In addition, the obtained particles were formed into a plate with a thickness of 0.40 mm using a hot press (manufactured by TESTER Industry (Co., Ltd.), and the tensile elastic modulus, tensile elongation at break, and impact strength were evaluated by the following method. The results are shown in Table 1.

[0142] <MFR and formability evaluation>

[0143] The measurement was performed at 200°C and 5 kg load or 220°C and 10 kg load according to JIS K 7210-2:2014 (ISO 133-2:2011). The formability was evaluated according to the following evaluation criteria, and when the evaluation was good or better, the effect of the present invention was considered to be exhibited.

[0144] (Evaluation Criteria)

[0145] Excellent: MFR (200°C, 5 kg load) or MFR (220°C, 10 kg load) is 10.0 g / 10 min or more.

[0146] Good: MFR (200° C., 5 kg load) or MFR (220° C., 10 kg load) is 4.0 g / 10 min or more and less than 10.0 g / 10 min.

[0147] Unqualified: MFR (200°C, 5kg load) or MFR (220°C, 10kg load) is less than 4.0g / 10min.

[0148] <Measurement method of tensile elastic modulus>

[0149] The measurement was performed using Autograph (manufactured by Shimadzu Corporation, product name "AGS-X") according to ASTM-D638. Specifically, a plate-like sample with a thickness of 0.40 mm was cut into the shape of dumbbell No. 1 to prepare a measurement sample, and the tensile elastic modulus of the measurement sample was measured at a tensile speed of 5 mm / min under the conditions of a measurement temperature of 23°C and a humidity of 50%. The evaluation was performed according to the following evaluation criteria, and if the evaluation was good or above, it was considered to show the effect of the present invention.

[0150] (Evaluation Criteria)

[0151] Excellent: The tensile modulus is 1,200 MPa or more and less than 1,800 MPa.

[0152] Good: The tensile elastic modulus is 800 MPa or more and less than 1,200 MPa.

[0153] Unqualified: The tensile modulus is less than 800 MPa or greater than 1,800 MPa.

[0154] <Determination method of tensile elongation at break>

[0155] The measurement was performed using Autograph (manufactured by Shimadzu Corporation, product name "AGS-X") according to ASTM-D638. Specifically, a plate-like sample with a thickness of 0.40 mm was cut into the shape of dumbbell No. 1 to prepare a measurement sample, and the tensile elongation at break of the sample was measured at a tensile speed of 5 mm / min under the conditions of a measurement temperature of 23°C and a humidity of 50%. The evaluation was performed according to the following evaluation criteria, and if the evaluation was above qualified, it was considered to show the effect of the present invention.

[0156] (Evaluation Criteria)

[0157] Excellent: The tensile elongation at break is 40% or more.

[0158] Good: The tensile elongation at break is 25% or more and less than 40%.

[0159] Pass: The tensile elongation at break is 15% or more and less than 25%.

[0160] Unqualified: tensile elongation at break is less than 15%.

[0161] <Impact Strength>

[0162] The impact strength was measured using a film impact tester (manufactured by Yasuda Seiki Co., Ltd.) according to ASTM-D3420. Specifically, a plate-like sample having a thickness of 0.40 mm was cut into 70 mm×70 mm to prepare a measurement sample, and the impact strength was measured. In addition, the evaluation was performed according to the following evaluation criteria.

[0163] (Evaluation Criteria)

[0164] Excellent: Impact strength is 2.0 J / mm or more.

[0165] Good: The impact strength is 1.5 J / mm or more and less than 2.0 J / mm.

[0166] Unqualified: impact strength is less than 1.5J / mm.

[0167] [Examples 2 to 20 and Comparative Examples 1 to 7]

[0168] The resin composition was prepared in the same manner as in Example 1 except that the composition of the resin composition was set as shown in Tables 1 to 2. In addition, pellets were prepared in the same manner as in Example 1 and the MFR was measured. Furthermore, the pellets were formed into a plate shape in the same manner as in Example 1, and the tensile elastic modulus, tensile elongation at break, and impact strength were measured. The results are shown in Tables 1 to 2.

[0169] Table 1

[0170]

[0171] Table 2

[0172]

[0173] As shown in Tables 1 to 2, the values ​​of tensile elastic modulus and tensile elongation at break of the resin compositions of Examples 1 to 20 satisfying the structure of the present embodiment are good. In addition, the formability is also good. On the other hand, the tensile elongation at break of the resin composition of Comparative Example 1 not containing the additive (C) is insufficient, and the formability is also poor. Furthermore, the tensile elongation at break of the resin compositions of Comparative Examples 2 to 4, which are formulated with additives (C) not containing compounds (c1) to (c3), is smaller than that of the resin composition of Comparative Example 1. Furthermore, the formability is also poor. In addition, the resin compositions of Comparative Examples 5 to 7, in which the total amount of compounds (c1) to (c3) in the additive (C) is 50% by mass or less, have good formability, but poor tensile elongation at break. From the above results, it can be seen that the resin composition of the present embodiment has good tensile elastic modulus and tensile elongation at break and is also excellent in formability. The resin composition of the present embodiment contains a certain amount of eggshell powder, and the load on the environment is also small.

[0174] Industrial availability

[0175] The resin combination of the present embodiment has good tensile elastic modulus and tensile elongation at break, and formability is also excellent. Therefore, it can be suitably used as injection molding resin combination. In addition, the molded product of the present embodiment is due to excellent tensile elastic modulus and tensile elongation at break, and contains a certain amount of eggshell powder, and is therefore a molded product with less environmental load. This molded product can be applied to purposes such as stationery, furniture, building materials, tableware, containers, gardening materials, toys, etc.

Claims

1. A resin composition comprising eggshell powder (A), a polystyrene resin (B), and an additive (C), The ratio of the eggshell powder (A) to 100 parts by mass of the total of the eggshell powder (A) and the polystyrene resin (B) is 20 parts by mass or more, The additive (C) comprises at least one compound selected from the group consisting of fatty amide (c1), sodium fatty acid (c2), and fatty acid ester (c3); the total content of the fatty amide (c1), the sodium fatty acid (c2), and the fatty acid ester (c3) exceeds 50% by mass relative to the total mass of the additive (C); and the content of the additive (C) is less than 10 parts by mass relative to a total of 100 parts by mass of the eggshell powder (A) and the polystyrene resin (B).

2. The resin composition according to claim 1, wherein The ratio of the eggshell powder (A) to 100 parts by mass of the total of the eggshell powder (A) and the polystyrene resin (B) is 70 parts by mass or less.

3. The resin composition according to claim 1 or 2, wherein The resin composition has an MFR of 4.0 g / 10 min or more under conditions of 200° C. and a load of 5 kg.

4. The resin composition according to claim 1 or 2, wherein The resin composition has an MFR of 4.0 g / 10 min or more under conditions of 220° C. and a load of 10 kg.

5. The resin composition according to claim 1 or 2, wherein The polystyrene resin (B) includes at least one resin selected from a general-purpose polystyrene resin (b1) and an impact-resistant polystyrene resin (b2), and a styrene-butadiene copolymer resin (b3).

6. The resin composition according to claim 1 or 2, wherein The polystyrene-based resin (B) includes an acrylonitrile-butadiene-styrene copolymer resin (b4).

7. The resin composition according to claim 1 or 2, wherein The average particle size of the eggshell powder (A) is 3 to 50 μm.

8. The resin composition according to claim 1 or 2, which is used for injection molding. 9 . A molded article comprising the resin composition according to claim 1 .

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