Resin composition and molded article comprising same

Abstract

To provide a resin composition having good ultraviolet shielding properties while maintaining the original characteristics of the resin composition.SOLUTION: The resin composition contains the thermoplastic resin and the inorganic powder at a mass ratio of 80:20 to 10:90. The amount of manganese element in the inorganic powder is 0.02 mass% or more and 1.00 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a molded article containing the same. [Background technology]

[0002] Conventionally, resin compositions in which inorganic powder such as calcium carbonate powder is filled into a thermoplastic resin have been known (see, for example, Patent Document 1). Molded articles of such resin compositions can use less resin than molded articles of resin compositions that do not contain inorganic powder, and can reduce the environmental load, and therefore are used in a wide range of applications, such as synthetic paper, daily necessities, food containers, cosmetic containers, automotive parts, building materials, home appliances, and optical design parts.

[0003] Among these applications, molded articles used outdoors are required to have ultraviolet shielding properties in order to protect the contents from ultraviolet rays and to improve weather resistance. Typically, thermoplastic resin compositions filled with inorganic powders are imparted with ultraviolet shielding properties by incorporating organic ultraviolet absorbers such as benzophenone-based and benzotriazole-based ones (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-77472 [Patent Document 2] Japanese Patent Application Publication No. 9-095592 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a resin composition contains an ultraviolet absorber, various problems may arise during molding or use of the resulting molded article, such as bleeding out of the ultraviolet absorber or yellowing when used in combination with a basic compound, impairing the inherent color of the resin composition, etc. Therefore, it has been desired to impart ultraviolet shielding properties without causing such various problems as much as possible (i.e., while maintaining the inherent properties of the resin composition).

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin composition that has good ultraviolet shielding properties while maintaining the inherent properties of the resin composition, and a molded article containing the same. [Means for solving the problem]

[0007] The present invention relates to the following resin composition and molded article. [1] A resin composition containing a thermoplastic resin and an inorganic powder in a mass ratio of 80:20 to 10:90, wherein the amount of manganese element in the inorganic powder is 0.02 mass % or more and 1.00 mass % or less. [2] The resin composition according to [1], wherein the amount of manganese element in the inorganic powder is 0.05% by mass or more and 0.50% by mass or less. [3] The resin composition according to [1] or [2], wherein the amount of manganese element in the inorganic powder is more than 0.10% by mass and not more than 0.30% by mass. [4] The resin composition according to any one of [1] to [3], wherein the amount of the manganese element in the inorganic powder is greater than the amount of the iron element in the inorganic powder. [5] The resin composition according to any one of [1] to [3], wherein the amount of sulfur element in the inorganic powder is 0.05% by mass or more and 1.0% by mass or less. [6] The resin composition according to any one of [1] to [5], wherein the thermoplastic resin comprises at least one of a polypropylene-based resin and a polyethylene-based resin. [7] The resin composition according to any one of [1] to [6], wherein the inorganic powder is calcium carbonate powder. [8] The resin composition according to [7], wherein the calcium carbonate powder is calcium carbonate powder made from at least one of iron and steel slag and calcium carbide slag. [9] The resin composition according to [7] or [8], wherein the calcium carbonate powder has an average particle size of 0.7 μm or more and 10.0 μm or less, as measured by an air permeability method in accordance with JIS M-8511:2014.

[10] The resin composition according to any one of [1] to [9], which contains the thermoplastic resin and the inorganic powder in a mass ratio of 75:25 to 25:75.

[11] A molded article comprising the resin composition according to any one of [1] to

[10] . [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition that has good ultraviolet shielding properties while maintaining the inherent properties of the resin composition, and a molded article containing the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a graph showing the measurement results of the spectral light transmittance of the resin sheets of the examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0010] It is known that inorganic powders usually contain trace elements derived from the raw materials or their synthesis process. In order to make the most of the inherent properties of the inorganic powders, such trace elements are often used after being reduced to or removed from a predetermined amount.

[0011] The present inventors conducted extensive research focusing on these trace elements and found that resin compositions using inorganic powders containing a predetermined amount or more of manganese as a trace element have a higher level of ultraviolet absorption than resin compositions using inorganic powders containing almost no manganese. This finding suggests that resin compositions can be imparted with good ultraviolet shielding properties without the use of an ultraviolet absorber. While the reason for this is unclear, it is believed that the presence of fine particles of manganese oxide or manganese carbonate in the polycrystalline or on the surface of inorganic particles absorbs ultraviolet light.

[0012] On the other hand, if the amount of manganese element in the inorganic powder is too high, the appearance of the molded product is likely to be impaired due to coloration of the inorganic powder, and the strength of the molded product is likely to be impaired due to oxidative degradation of the resin. In contrast, it has been found that these problems can be suppressed by setting the amount of manganese element in the inorganic powder to a specified amount or less.

[0013] That is, the resin composition of the present invention contains a thermoplastic resin and an inorganic powder, and the amount of manganese element in the inorganic powder is in the range of 0.02% by mass to 1.00% by mass, thereby imparting ultraviolet shielding properties to the resin composition while maintaining the inherent properties of the resin composition.

[0014] Hereinafter, one embodiment of the present invention will be described in detail. However, the present invention is not limited to this embodiment. Furthermore, in this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0015] 1.Resin composition The resin composition of the present embodiment contains a thermoplastic resin and an inorganic powder.

[0016] The mass ratio of the thermoplastic resin to the inorganic powder contained in the resin composition is 80:20 to 10:90 (mass ratio), and preferably 75:25 to 25:75 (mass ratio). By setting the mass ratio of the thermoplastic resin to the inorganic powder within the above range, the amount of resin can be reduced, and a resin composition with a lower environmental impact can be obtained.

[0017] 1-1.Thermoplastic resin The thermoplastic resin preferably contains a polyolefin resin as a main component. The amount of the polyolefin resin in the thermoplastic resin is, for example, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The thermoplastic resin may contain only one type of polyolefin resin, or may contain two or more types.

[0018] Polyolefin resins are resins whose main component is an olefin-derived structural unit. The polyolefin resin is a resin in which the amount of olefin-derived structural units relative to all structural units constituting the polyolefin resin is 50% by mass or more. The polyolefin resin may be a homopolymer of one type of olefin, a copolymer of two or more types of olefins, or a copolymer of one or more types of olefins with one or more other monomers (monomers other than olefins). The amount of olefin-derived structural units in the polyolefin resin is preferably 75% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0019] Examples of olefins include ethylene and α-olefins having 3 to 10 carbon atoms. Specific examples of olefins include ethylene, propylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, 4-methylpentene-1, 3-methyl-1-hexene, and 1-octene. Polyolefin resins may contain only one type of structural unit derived from these, or may contain two or more types.

[0020] Examples of other monomers include diene monomers such as 1,4-hexadiene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, dicyclopentadiene (DCPD), ethylidene norbornene (ENB), norbornadiene, and 5-vinyl-2-norbornene; acid (or acid anhydride)-modified olefins such as maleic anhydride-modified olefins; and (meth)acrylates such as methyl (meth)acrylate. The polyolefin resin may contain only one type of structural unit derived from these, or may contain two or more types.

[0021] The polyolefin resin preferably contains at least one of a polypropylene resin and a polyethylene resin. The polypropylene resin and the polyethylene resin may be virgin resin, recycled resin, or a mixture thereof.

[0022] In this specification, the term "polypropylene resin" refers to a resin containing 50% by mass or more of structural units derived from propylene, and includes propylene homopolymers and copolymers of propylene with other monomers (propylene copolymers). Propylene homopolymers include isotactic, syndiotactic, atactic, hemiisotactic, and linear or branched polypropylenes exhibiting various stereoregularities. The stereoregularity of propylene is 13 The propylene copolymer can be identified by C-NMR or the like. The propylene copolymer may be a random copolymer or a block copolymer. The propylene copolymer may be a binary copolymer of propylene and another monomer, or a multi-component copolymer of propylene and two or more other monomers. Examples of preferred copolymerization components (other monomers) include ethylene, α-olefins having 4 or more carbon atoms, tetrafluoroethylene, vinyl acetate, etc. In this embodiment, the polypropylene-based resin is preferably a propylene homopolymer or a propylene copolymer containing less than 5 mass% of structural units derived from other monomers.

[0023] In this specification, the term "polyethylene-based resin" refers to a resin containing 50% by mass or more of structural units derived from ethylene, and includes ethylene homopolymers and copolymers of ethylene and other monomers (ethylene copolymers). Examples of ethylene homopolymers include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, and linear low-density polyethylene (LLDPE). The ethylene copolymer may be a binary copolymer of ethylene and other monomers, or a multi-component copolymer of ethylene and two or more other monomers. Examples of preferred copolymerization components (other monomers) include vinyl acetate and α-olefins having 3 or more carbon atoms. In this embodiment, the polyethylene-based resin is preferably an ethylene homopolymer or an ethylene copolymer containing less than 5% by mass of structural units derived from other monomers.

[0024] The thermoplastic resin may further include a resin other than the polyolefin-based resin, as described above. Examples of the resin other than the polyolefin-based resin include thermoplastic resins such as poly(meth)acrylic acid (ester), polyvinyl acetate, polyacrylonitrile, polystyrene, ABS resin, polycarbonate, polyamide, polyvinyl alcohol, petroleum hydrocarbon resin, and coumarone-indene resin; and elastomers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-ethylene copolymer, styrene-isoprene-ethylene copolymer, acrylonitrile-butadiene copolymer, and fluorine-based elastomer.

[0025] The content of the thermoplastic resin in the resin composition is not particularly limited, but is preferably 5% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 75% by mass or less, and even more preferably 30% by mass or more and 65% by mass or less, relative to the total amount of the resin composition. When the content of the thermoplastic resin is equal to or greater than the lower limit, the proportion of inorganic powder does not become too high, which can improve the molding processability and the appearance of the molded product. When the content of the thermoplastic resin is equal to or less than the upper limit, not only can the environmental load be reduced, but the proportion of inorganic powder does not become too low, which can increase the mechanical strength.

[0026] 1-2.Inorganic powder The inorganic powder is a powder made of an inorganic substance. The type of inorganic substance can be selected depending on the application of the resin composition. Examples of inorganic substances include carbonates, silicates, phosphates, borates, sulfates, oxides, hydroxides, or hydrates of calcium, magnesium, aluminum, titanium, zinc, silicon, barium, molybdenum, sodium, and potassium. Examples of inorganic substances also include inorganic carbon compounds.

[0027] Specific examples of inorganic substances include calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay (e.g., talc, kaolin, etc.), aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, dolomite, graphite, etc. These may be synthetic or made from natural minerals. The inorganic powder may contain only one of these or two or more.

[0028] Preferred examples of inorganic powders include calcium carbonate, magnesium carbonate, dolomite, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, calcium sulfate, aluminum hydroxide, and magnesium hydroxide powders, with calcium carbonate powder being particularly preferred.

[0029] The calcium carbonate may be so-called light calcium carbonate, which is prepared by a synthetic method, or so-called heavy calcium carbonate, which is obtained by mechanically crushing and classifying a natural raw material containing CaCO as a main component, such as limestone. Of these, light calcium carbonate is preferred from the viewpoint of easier adjustment of the amount of manganese element in the calcium carbonate.

[0030] In this embodiment, the calcium carbonate powder is preferably a powder made from concrete sludge, steel slag, carbide slag, waste concrete, coal ash, biomass ash, incineration ash, waste gypsum, alkaline wastewater, etc., and more preferably a powder made from steel slag and / or carbide slag. In calcium carbonate powder made from these raw materials, the amount of manganese element in the calcium carbonate powder can be easily adjusted to the range described below.

[0031] In this way, calcium-containing waste, such as steel slag or carbide slag, or calcium extracted from such waste, is reacted with carbon dioxide, which causes the greenhouse effect, to prepare calcium carbonate powder, thereby reducing the environmental load.

[0032] As described above, the amount of elemental manganese in the inorganic powder is 0.02% by mass or more and 1.00% by mass or less. When the amount of elemental manganese in the inorganic powder is 0.02% by mass or more, ultraviolet shielding properties can be imparted to the resin composition. When the amount of elemental manganese in the inorganic powder is 1.00% by mass or less, deterioration in the appearance (color) and strength of the resulting molded product can be reduced. From the same viewpoint, the amount of elemental manganese in the inorganic powder is preferably 0.05% by mass or more and 0.50% by mass or less, more preferably 0.10% by mass or more and 0.30% by mass or less, and even more preferably more than 0.10% by mass and 0.30% by mass or less. Manganese may be contained in the inorganic powder as a simple substance or as a compound with other elements, such as an oxide, sulfide, nitride, or sulfide. When two or more types of inorganic powders are contained, the amount of elemental manganese in the inorganic powder refers to the total amount of elemental manganese relative to the total amount of inorganic powders.

[0033] The inorganic powder may further contain trace elements other than manganese. For example, when the inorganic powder is calcium carbonate powder, examples of trace elements other than manganese include iron (Fe), sulfur (S), magnesium (Mg), and silicon (Si). For example, the inorganic powder may further contain iron or sulfur. This can impart higher ultraviolet shielding properties to the resin composition.

[0034] When the inorganic powder further contains iron, the amount of iron in the inorganic powder is preferably less than the amount of manganese in the inorganic powder, for example, 0.01% by mass to 0.80% by mass, preferably 0.02% by mass to 0.30% by mass. When the inorganic powder further contains sulfur, the amount of sulfur in the inorganic powder is, for example, 0.02% by mass to 1.00% by mass, preferably 0.05% by mass to 0.50% by mass. When the amount of iron or sulfur in the inorganic powder is equal to or greater than the lower limit, the ultraviolet shielding properties of the molded article can be further improved. When the amount of iron or sulfur in the inorganic powder is equal to or less than the upper limit, poor appearance of the molded article due to discoloration of the inorganic powder and reduction in strength of the molded article due to oxidative degradation of the resin can be further suppressed.

[0035] The types and amounts of elements contained in inorganic powders can be identified by X-ray fluorescence analysis (XRF). Approximately 30 mg of inorganic powder is placed in an aluminum pan with an inner diameter of 30 mm and a depth of 5 mm, and a pressure of 20 MPa is applied for 2 seconds to produce a molded plate. The resulting molded plate is subjected to X-ray fluorescence analysis using an X-ray fluorescence analyzer (e.g., Rigaku Corporation, ZSX Primus IV) under the following conditions to identify the types and amounts of elements contained in the inorganic powder. (Measurement conditions) X-ray tube: Rh target 4kW X-ray irradiation method: Top irradiation Measuring diameter: 10 mm Integration time: 30 minutes per sample Detected elements: B to U Measurement atmosphere: under vacuum

[0036] The elements in the inorganic powder can be quantitatively determined by the fundamental parameter method.

[0037] Furthermore, when the above measurement is performed on inorganic powder separated and recovered from the resin composition, the method for separating and recovering the inorganic powder from the resin composition may be, for example, a method in which the resin composition is heated at 550°C for 30 minutes to heat and incinerate the organic matter, and then the inorganic powder remaining as a residue is recovered.

[0038] The amount of elemental manganese and the like in the inorganic powder can be adjusted by any method.

[0039] For example, when the inorganic powder is calcium carbonate powder and a calcium-containing compound containing a large amount of manganese is used as a raw material, the amount of manganese can be adjusted by controlling the calcium carbonate synthesis process. Specifically, for example, the extraction rate can be controlled in a step of preparing a calcium-containing solution containing calcium extracted by adjusting the pH from calcium-containing waste such as steel slag or carbide slag. In this method, the higher the extraction rate, the more trace elements such as manganese can be extracted. Therefore, by controlling the extraction rate, the amount of manganese and other trace elements in the resulting calcium carbonate powder can be adjusted.

[0040] On the other hand, when a calcium-containing compound containing little or no manganese is used as a raw material, the amount of manganese may be adjusted by adding a manganese source during the calcium carbonate synthesis process (carbonation process). The manganese source may be an inorganic salt of manganese (e.g., manganese chloride, manganese sulfate, manganese carbonate, manganese acetate, etc.), an organic salt, an oxide, a hydroxide, etc.

[0041] The amount of elemental manganese may be adjusted by mixing a manganese compound powder with the calcium carbonate powder. Examples of the manganese compound powder include manganese oxide, manganese carbonate, manganese sulfate, and the like.

[0042] The shape of the inorganic powder is not particularly limited, and may be any of particles, flakes, granules, fibers, etc. In addition, in the case of particles, they may be spherical as obtained by general synthesis methods, or may be irregularly shaped as obtained by pulverizing collected natural minerals.

[0043] Here, the inorganic powder may be surface-modified or may not be surface-modified. From the viewpoint of improving dispersibility, it is preferable that the inorganic powder be surface-modified. Examples of methods for surface modification of inorganic powders include physical modification methods such as plasma treatment and chemical modification methods using coupling agents, surfactants, etc. Examples of coupling agents that can be used in chemical modification methods include silane coupling agents and titanium coupling agents. As surfactants, any of anionic, cationic, nonionic, and amphoteric surfactants can be used, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides, and higher fatty acid salts.

[0044] The average particle size of the inorganic powder is not particularly limited and can be appropriately selected depending on the shape and thickness of the molded article, but is preferably 0.7 μm to 10.0 μm, and more preferably 0.7 μm to 6.0 μm. When the average particle size of the inorganic powder is 10.0 μm or less, the inorganic powder is less likely to fall off from the molded article obtained from the resin composition. When the average particle size of the inorganic powder is 0.7 μm or more, the viscosity when kneaded with the thermoplastic resin is more likely to fall within the desired range.

[0045] The average particle size of the inorganic powder can be calculated from the results of measuring the specific surface area by the air permeability method in accordance with JIS M-8511: 2014. An example of the measuring instrument is the SS-100 specific surface area measuring device manufactured by Shimadzu Corporation.

[0046] The content of inorganic powder in the resin composition is not particularly limited, but is preferably 15% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 75% by mass or less, and even more preferably 30% by mass or more and 65% by mass or less, relative to the total amount of the resin composition. When the content of inorganic powder is equal to or greater than the lower limit, the mechanical strength of the resin composition can be further increased. When the content of inorganic powder is equal to or less than the upper limit, the moldability and appearance can be further maintained. The content of calcium carbonate powder in the inorganic powder may be, for example, 50% by mass or more, 70% by mass or more, or 100% by mass.

[0047] 1-3.Other ingredients The resin composition may further contain other components in addition to those described above, provided that the purpose and effect of the present embodiment are not impaired. Examples of the other components include lubricants, plasticizers, colorants, antioxidants, flame retardants, foaming agents, and flow control agents.

[0048] Examples of lubricants include fatty acid-based lubricants such as stearic acid, hydroxystearic acid, complex stearic acid, and oleic acid; fatty alcohol-based lubricants; aliphatic amide-based lubricants such as stearamide, oxystearamide, oleylamide, erucylamide, ricinoleamide, behenamide, methylolamide, methylenebisstearamide, methylenebisstearobenamide, bisamic acids of higher fatty acids, and complex amides; aliphatic ester-based lubricants such as n-butyl stearate, methyl hydroxystearate, polyhydric alcohol fatty acid esters, saturated fatty acid esters, and ester waxes; and fatty acid metal soap-based lubricants, such as zinc stearate and magnesium stearate.

[0049] Examples of plasticizers include triethyl citrate, acetyl triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, dioctyl phthalate, di(2-ethylhexyl) phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, o-benzoylbenzoic acid ester, diacetin, epoxidized soybean oil, etc. The resin composition may contain these alone or in combination.

[0050] The coloring material may be any of known organic or inorganic pigments or dyes. Specific examples of coloring materials include organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, dioxazine-based, perinone-based, quinophthalone-based, and perylene-based pigments; and inorganic pigments such as ultramarine, titanium yellow, and chromium oxide. The resin composition may contain these pigments alone or in combination.

[0051] Examples of antioxidants include phosphorus-based antioxidants, phenol-based antioxidants, and pentaerythritol-based antioxidants. The resin composition may contain these antioxidants alone or in combination. Phosphorus-based antioxidants, more specifically, phosphorus-based antioxidants such as phosphites and phosphate esters, are preferably used. Examples of phosphites include triesters, diesters, and monoesters of phosphorous acid, such as triphenyl phosphite, trisnonylphenyl phosphite, and tris(2,4-di-t-butylphenyl) phosphite.

[0052] Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl) phosphate, 2-ethylphenyldiphenyl phosphate, and the like.

[0053] Examples of phenolic antioxidants include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenylacrylate, 2,6-di-t-butyl-4-(N,N-dimethylaminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, and tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane.

[0054] The flame retardant is not particularly limited, but may be, for example, a halogen-based flame retardant or a non-phosphorus-based halogen-based flame retardant such as a phosphorus-based flame retardant or a metal hydrate. The resin composition may contain one or more of these.

[0055] Examples of halogen-based flame retardants include halogenated bisphenol compounds such as halogenated bisphenylalkanes, halogenated bisphenylethers, halogenated bisphenylthioethers, and halogenated bisphenylsulfones, as well as bisphenol-bis(alkyl ether) compounds such as brominated bisphenol A, brominated bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S. Examples of phosphorus-based flame retardants include aluminum tris(diethylphosphinate), bisphenol A bis(diphenylphosphate), triarylisopropyl phosphate, cresyl di-2,6-xylenyl phosphate, and aromatic condensed phosphate esters. Examples of metal hydrates include aluminum trihydrate, magnesium dihydroxide, and combinations thereof.

[0056] The flame retardant may also be combined with a flame retardant synergist. Examples of the flame retardant synergist include antimony oxides such as antimony trioxide and antimony pentoxide, and other known flame retardant synergists.

[0057] The foaming agent is not particularly limited as long as it is a compound that can generate bubbles when mixed or injected into a composition that is in a molten state in a melt kneader. Examples of foaming agents include those that change phase from solid to gas to generate bubbles, those that change phase from liquid to gas to generate bubbles, and gas itself.

[0058] Examples of blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane, and cyclohexane; halogenated hydrocarbons such as chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, and perfluorocyclobutane; inorganic gases such as carbon dioxide, nitrogen, and air; and water.

[0059] The foaming agent may contain an active ingredient of the foaming agent together with a carrier resin. Examples of the carrier resin include crystalline olefin resins such as crystalline propylene. Examples of the active ingredient include bicarbonates. Among these, bicarbonates are preferred. A foaming agent concentrate containing a crystalline polypropylene resin as the carrier resin and bicarbonates as the thermal decomposition type foaming agent is preferred.

[0060] Known fluidity modifiers can also be used. Examples of fluidity modifiers include peroxides such as dialkyl peroxides, for example, 1,4-bis[(t-butylperoxy)isopropyl]benzene. Depending on the type of thermoplastic resin used, these peroxides can also function as crosslinking agents. In particular, when the thermoplastic resin (polyolefin resin) has a diene-derived structural unit, the diene may be crosslinked by the peroxide.

[0061] Examples of antistatic agents include fatty acid diethanolamides such as lauryl diethanolamide and stearyl diethanolamide; and hydroxyl group-containing compounds such as alcohol amine compounds. Alcohol amines, such as monoethanolamine, diethanolamine, and triethanolamine, are particularly preferred. Two or more types of antistatic agents can also be used in combination. These antistatic agents may be supported on calcium silicate, calcium carbonate, or the like. The number of carbon atoms in the acyl group of the fatty acid diethanolamide is preferably 8 to 22, in order to achieve sufficient antistatic effect.

[0062] The total amount of other components in the resin composition is not particularly limited, but can be, for example, 5% by mass or less relative to the total amount of the resin composition.

[0063] 1-4. Shape of resin composition The shape of the resin composition is not particularly limited, and can be any shape, such as particulate, pellet, or block. When the resin composition is in pellet form, the shape of the pellet is not particularly limited, and can be any shape, such as cylindrical, spherical, or oval sphere. The size is also not particularly limited, and is selected appropriately depending on the shape. For example, in the case of spherical pellets, the diameter may be 1 to 10 mm. In the case of oval sphere pellets, the major axis can be about 1 to 10 mm, and the aspect ratio can be about 0.1 to 1.0. In the case of cylindrical pellets, the diameter can be about 1 to 10 mm, and the height can be about 1 to 10 mm.

[0064] 1-5.Method for producing resin composition The resin composition can be produced by mixing the above-mentioned thermoplastic resin, inorganic powder, and, if necessary, other components.

[0065] The mixing method is not particularly limited, and may be, for example, a method by melt kneading. All components may be mixed and then melt kneaded, or only some of the components may be melt kneaded first and the remaining components may be kneaded later. The device for melt kneading is not particularly limited, and a general extruder, kneader, Banbury mixer, etc. can be used. From the viewpoint of obtaining a resin composition with a particularly uniform composition, kneading with a twin-screw kneader is preferred.

[0066] 2. Molded products By molding the above-described resin composition, a molded article containing the resin composition can be obtained.

[0067] The molding method is not particularly limited, and may be any of inflation molding, extrusion molding, injection molding, foam injection molding, injection compression molding, blow molding, press molding, calendar molding, vacuum molding, and the like.

[0068] The shape and use of the molded product are not particularly limited, and it can be used for films, sheets, containers (food containers, etc.), daily necessities, automobile parts, electric and electronic parts, various consumables, etc. For example, the above-mentioned resin composition can be extruded into an extrusion-molded sheet. [Example]

[0069] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0070] 1. Material Preparation The following materials were used to prepare the resin compositions of the examples and comparative examples.

[0071] 1-1.Inorganic powder Calcium carbonate powder: calcium carbonate powder shown in Table 1 below [Table 1] Mn compound powder (manganese carbonate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0072] The amount of each element contained in the calcium carbonate powder was measured by the following method.

[0073] (Method for determining elements in calcium carbonate powder) Approximately 30 mg of calcium carbonate powder was placed on an aluminum pan with an inner diameter of 30 mm and a depth of 5 mm, and pressed at 20 MPa for 2 seconds to produce a molded plate. The obtained molded plate was subjected to X-ray fluorescence analysis under the following conditions to measure the amounts of elements contained in the calcium carbonate powder. (Measurement conditions) Equipment: X-ray fluorescence analyzer ZSX Primus IV (Rigaku Corporation) X-ray tube: Rh target 4kW X-ray irradiation method: Top irradiation Measuring diameter: 10 mm Integration time: 30 minutes per sample Detected elements: B to U Measurement atmosphere: under vacuum

[0074] The quantitative determination of each element in the calcium carbonate powder was carried out by the fundamental parameter method.

[0075] 1-2.Thermoplastic resin PP (homopolypropylene, Prime Polymer E111G) PE (high density polyethylene, HF313 manufactured by Japan Polyethylene Corporation)

[0076] 1-3.Other Lubricant (stearic acid, manufactured by Kao Corporation) Antistatic agent (lithium salt, manufactured by Marubishi Yuka Kogyo Co., Ltd.) Antioxidant 1 (phenolic antioxidant, manufactured by ADEKA) Antioxidant 2 (phosphite antioxidant, manufactured by ADEKA)

[0077] 2. Preparation of resin compositions and molded products [Examples 1 to 7 and 9 to 14, Comparative Examples 1 to 6] (Pellet production) The thermoplastic resin, inorganic powder, and other components were fed into a Parker HK-25D co-rotating twin-screw kneading extruder (φ25 mm, L / D=41) in the mass ratios shown in Tables 2 and 3, melt-kneaded at a cylinder temperature of 230°C, and then extruded into strands. The extruded resin composition was then cooled and cut to obtain pellets of the resin composition.

[0078] (Sheet production) The obtained pellets were charged into a T-die extrusion molding device (φ20 mm, L / D=25) manufactured by Toyo Seiki Seisaku-sho, and extruded at 240° C. to obtain a sheet having a thickness of 400 μm.

[0079] [Example 8, Comparative Example 7] As shown in Table 3, pellets of the resin composition were obtained in the same manner as in Example 1, except that the thermoplastic resin was changed to PE and the cylinder temperature was changed to 220°C, and then a sheet was produced.

[0080] 3. Evaluation The sheets obtained in Examples 1 to 14 and Comparative Examples 1 to 7 were evaluated as follows.

[0081] 3-1.UV shielding property The prepared sheet was cut into a size of 50 mm x 50 mm to prepare a test piece. The spectral light transmittance of this test piece was measured using an ultraviolet-visible spectrophotometer. The measurement conditions were as follows: (Measurement conditions) Equipment: UV-3600i Plus ultraviolet-visible infrared spectrophotometer (Shimadzu Corporation) Measurement wavelength range: 210 to 800 nm Scan speed: 600nm / min Measurement wavelength interval: 1nm

[0082] The ultraviolet ray blocking ability was evaluated based on the transmittance at 350 nm, according to the following criteria. ◎: Transmittance of 350 nm is less than 2% ○: Transmittance of 350 nm is 2% or more and less than 5% △: Transmittance of 350 nm is 5% or more but less than 10% ×: Transmittance of 350 nm is 10% or more

[0083] 3-2. Appearance (color) The color of the sheet was evaluated based on the transmittance at 500 nm and 700 nm (transmittance in the visible light range) in the above-mentioned measurement of spectral transmittance, according to the following criteria. ◎: The transmittance at 500 nm is 20% or more, and the ratio of the transmittance at 500 nm to that at 700 nm (T 500 / T 700 ) is 0.8 or more ○: The transmittance at 500 nm is 20% or more, and the ratio of the transmittance at 500 nm to that at 700 nm (T 500 / T 700 ) is 0.6 or more and less than 0.8 ×: The transmittance at 500 nm is 20% or more, and the ratio of the transmittance at 500 nm to that at 700 nm (T 500 / T 700 ) is less than 0.6 ××: Transmittance at 500 nm is less than 20% Transmittance and ratio at 500 nm (T 500 / T 700 ) means that there is no significant absorption in the visible light range and there is little coloration.

[0084] 3-3.Tensile strength Dumbbell-shaped test pieces were prepared from the obtained sheets in accordance with JIS K7161-2:2014. The tensile strength of the test pieces was measured in accordance with JIS K7161-2:2014 using an autograph AG-100kNXplus (Shimadzu Corporation) under conditions of 23°C and 50% RH. The test speed was 50 mm / min. The tensile strength was evaluated based on the following criteria. ◎: Tensile strength is 23 MPa or more ○: Tensile strength is 18 MPa or more and less than 23 MPa ×: Tensile strength is less than 18 MPa

[0085] 3-4.Evaluation results The evaluation results of Examples 1 to 7 and Comparative Examples 1 to 6 are shown in Table 2, and the evaluation results of Examples 8 to 14 and Comparative Example 7 are shown in Table 3. FIG. 1 shows a graph illustrating the measurement results of the spectral light transmittance of the resin sheets of PP (homopolypropylene), Example 1, Comparative Example 1, and Comparative Example 2.

[0086] [Table 2]

[0087] [Table 3]

[0088] 1, when the amount of manganese element in the inorganic powder is less than 0.02% by mass (Comparative Examples 1 to 3, 5 to 7), the transmittance of 300 to 350 nm is relatively high and the ultraviolet shielding ability is low. On the other hand, when the amount of manganese element in the inorganic powder is more than 1.00% by mass (Comparative Example 4), the appearance (color) and tensile strength of the sheet are slightly deteriorated.

[0089] In contrast, when the amount of manganese element in the inorganic powder was adjusted to 0.02% by mass or more and 1.00% by mass or less (Examples 1 to 14), the transmittance at 300 to 350 nm was low, and the UV blocking ability was high.In addition, the deterioration of the appearance and tensile strength of the sheet was also small, and it was found to be good.

[0090] In particular, it is clear that the greater the amount of manganese element in the inorganic powder, the lower the transmittance at 350 nm and the higher the ultraviolet ray shielding property (comparison between Examples 1 to 6).

[0091] It is also clear that the higher the content ratio of inorganic powder to thermoplastic resin, the lower the transmittance at 350 nm and the higher the ultraviolet shielding property (comparison between Examples 1 and 7).

[0092] It is also clear that when the amount of iron element in the inorganic powder is lower than the amount of manganese element, the deterioration in the appearance and tensile strength of the sheet is less (comparison between Examples 4 and 11).It is also clear that when the amount of sulfur element in the inorganic powder is moderately high, the transmittance at 350 nm is lower and the ultraviolet shielding property is higher (comparison between Examples 1 and 12).

[0093] It is also clear that the smaller the average particle size of the inorganic powder, the less deterioration there is in the appearance of the sheet (comparison between Examples 1 and 13). [Industrial Applicability]

[0094] According to the present invention, it is possible to provide a resin composition that has good ultraviolet shielding properties while maintaining the inherent properties of the resin composition, and a molded article containing the same.

Claims

1. It contains thermoplastic resin and inorganic powder in a mass ratio of 80:20 to 10:

90. The amount of manganese element in the inorganic powder is 0.02% by mass or more and 1.00% by mass or less. The amount of sulfur element in the inorganic powder is 0.05% by mass or more and 1.0% by mass or less. Resin composition.

2. The amount of manganese element in the inorganic powder is 0.05% by mass or more and 0.50% by mass or less. The resin composition according to claim 1.

3. The amount of manganese element in the inorganic powder is greater than 0.10% by mass and less than or equal to 0.30% by mass. The resin composition according to claim 1.

4. The amount of manganese element in the inorganic powder is greater than the amount of iron element in the inorganic powder. The resin composition according to claim 1.

5. The thermoplastic resin comprises at least one of a polypropylene resin and a polyethylene resin. The resin composition according to claim 1.

6. The inorganic powder is calcium carbonate powder. The resin composition according to claim 1.

7. The calcium carbonate powder is a calcium carbonate powder made from at least one of steel slag and calcium carbide slag as raw materials. The resin composition according to claim 6.

8. The average particle size of the calcium carbonate powder, as measured by the air permeation method in accordance with JIS M-8511:2014, is 0.7 μm or more and 10.0 μm or less. The resin composition according to claim 6.

9. The thermoplastic resin and the inorganic powder are contained in a mass ratio of 75:25 to 25:

75. The resin composition according to claim 1.

10. A resin composition comprising the resin composition according to any one of claims 1 to 9, Molded products.

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