Resin composition, method for producing resin composition, polyolefin-based resin composition, method for producing polyolefin-based resin composition, and molded body

Abstract

Provided are: a resin composition which enables the production of a molded body that emits relatively small amounts of VOCs although a plant-derived filler is contained; a method for producing the resin composition; a polyolefin-based resin composition; a method for producing the polyolefin-based resin composition; and a molded body comprising the resin composition or the polyolefin-based resin composition.

Description

Resin composition, method for producing resin composition, polyolefin-based resin composition, method for producing polyolefin-based resin composition, and molded article

[0001] The present invention relates to a resin composition, a method for producing the resin composition, a polyolefin-based resin composition, a method for producing the polyolefin-based resin composition, and a molded article containing the resin composition or the polyolefin-based resin composition.

[0002] Molded articles containing resin compositions are used in household goods, automobile parts, industrial parts such as electrical parts, daily necessities, miscellaneous goods, etc. Fillers are blended into such resin compositions to enhance mechanical strength, etc. Examples of such fillers include inorganic powders such as talc and silica; cellulose-based powders such as wood flour and bamboo flour; and fibrous fillers such as natural fibers, glass fibers, and carbon fibers.

[0003] In recent years, resin compositions containing plant-derived fillers such as cellulose-based powders such as wood flour and bamboo flour have been attracting attention from the viewpoints of reducing environmental impact, being carbon neutral, etc. As such a resin composition, for example, Patent Document 1 discloses wood flour pellets containing atactic polypropylene and wood flour.

[0004] Japanese Unexamined Patent Publication No. 54-11162

[0005] However, molded articles containing resin compositions blended with plant-derived fillers such as wood flour pellets emit relatively large amounts of volatile organic compounds (hereinafter referred to as VOCs), and the odor caused by VOCs is a problem.

[0006] The present invention has been made in view of such problems, and an object of the present invention is to provide a resin composition that contains a plant-derived filler but that can produce a molded article that emits relatively little VOCs, a method for producing the resin composition, a polyolefin-based resin composition, a method for producing the polyolefin-based resin composition, and a molded article that contains the resin composition or the polyolefin-based resin composition.

[0007] The resin composition according to the present invention comprises a plant-derived filler (C) and a hydrophilic resin (D) having a hydroxyl group, wherein the content of the plant-derived filler (C) is 20% by mass or more and 91% by mass or less, and the content of the hydrophilic resin (D) having a hydroxyl group is 9% by mass or more and 80% by mass or less, where the total content of (C) and (D) is 100% by mass.

[0008] The method for producing a resin composition according to the present invention is a method for producing the resin composition, and includes a step of kneading a plant-derived filler (C) and a hydrophilic resin (D) having a hydroxyl group using a kneader.

[0009] The polyolefin resin composition according to the present invention comprises a polyolefin resin (A), a modified polyolefin resin (B), a plant-derived filler (C), and a hydrophilic resin having a hydroxyl group (D), wherein, when the total content of (A), (B), (C), and (D) is 100% by mass, the content of the polyolefin resin (A) is 1% by mass or more and 96.4% by mass or less, the content of the modified polyolefin resin (B) is 1% by mass or more and 20% by mass or less, the content of the plant-derived filler (C) is 1% by mass or more and 80% by mass or less, and the content of the hydrophilic resin having a hydroxyl group (D) is 1% by mass or more and 30% by mass or less.

[0010] The method for producing a polyolefin resin composition according to the present invention is a method for producing the polyolefin resin composition, and includes the following steps 1 and 2: Step 1: kneading a plant-derived filler (C) and a hydrophilic resin (D) having a hydroxyl group using a kneader; and Step 2: after Step 1, adding a polyolefin resin (A) and a modified polyolefin resin (B) and kneading them.

[0011] The molded article according to the present invention contains the resin composition or the polyolefin resin composition.

[0012] According to the present invention, it is possible to provide a resin composition that contains a plant-derived filler but is capable of producing a molded article that emits relatively little VOCs, a method for producing the resin composition, a polyolefin-based resin composition, a method for producing the polyolefin-based resin composition, and a molded article that contains the resin composition or the polyolefin-based resin composition.

[0013] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0014] 1. Resin Composition The resin composition according to this embodiment contains a plant-derived filler (C) and a hydrophilic resin (D) having a hydroxyl group.

[0015] [Plant-derived filler (C)] The plant-derived filler (C) may be any component that contains at least a plant-derived component and can be dispersed in the polyolefin-based resin (A). Various known plant-derived fillers can be used as the plant-derived filler (C). Examples of the plant-derived filler (C) include cellulose, wood flour, bamboo flour, rice, rice bran, and starch. Among these, the plant-derived filler (C) is preferably cellulose, wood flour, or bamboo flour, and more preferably cellulose or wood flour. From the viewpoint of ease of handling, the plant-derived filler (C) may be a bundle solidified using an adhesive such as a fiber-bundling agent. The resin composition may contain only one type of plant-derived filler (C), or two or more types.

[0016] Examples of cellulose include powdered cellulose, cellulose fiber, and lignocellulose fiber. Examples of raw materials for cellulose include natural materials such as wood (coniferous and broad-leaved trees), cotton linter, kenaf, Manila hemp (abaca), sisal, jute, sabai grass, esparto grass, bagasse, rice straw, wheat straw, reed, and bamboo. Cellulose may also be modified with a functional monomer including, for example, an acid, an amine, or an epoxy. Among these, the cellulose is preferably cellulose fiber.

[0017] Examples of cellulose fibers include wood-based pulp obtained from conifers, broad-leaved trees, etc.; recycled paper pulp, which is a recycled product of such wood-based pulp; non-wood-based pulp such as cotton or linter obtained from cotton, straw obtained from rice, bamboo obtained from bamboo, abaca obtained from Manila hemp, jute obtained from Indian hemp, and hemp obtained from flax; and regenerated cellulose fibers such as pulp using cereal fibers discarded during food processing, rayon fiber, and lyocell. Among these, the cellulose fiber is preferably wood-based pulp or recycled paper pulp, and more preferably wood-based pulp.

[0018] Pulp is a plant molding that has had the lignin, oil, and other components removed, or has had the hemicellulose content minimized, from among the cellulose, lignin, hemicellulose, oil, and other components contained therein. Depending on the application, the pulp may be bleached to whiten it.

[0019] The cellulose fibers may be obtained by chemically or mechanically pulverizing the pulp to produce fine particles of 1 mm or less, or may be fine microfibrillated cellulose fibers that have been partially converted into nanocellulose.

[0020] The cellulose fibers may be biomass nanofibers. In this specification, biomass nanofibers refer to either long fiber biomass nanofibers or short fiber biomass nanofibers.

[0021] Examples of biomass nanofibers include cellulose nanofibers (CNF), chitin nanofibers, chitosan nanofibers, silk nanofibers, etc. Among these, the biomass nanofiber is preferably cellulose nanofibers (CNF) from the viewpoints of chemical stability, thermal stability, and cost.

[0022] From the viewpoint of aspect ratio, the average fiber diameter of biomass nanofibers is preferably 3 nm to 100 nm, more preferably 10 nm to 50 nm. The average fiber diameter can be calculated from the average value of fiber diameters (n = approximately 20) measured based on electron microscope photographs taken at an appropriate magnification.

[0023] Examples of biomass nanofibers include mechanically defibrated biomass nanofibers produced by mechanical defibration, chemically modified biomass nanofibers produced through chemical modification, etc. Among these, the biomass nanofibers are preferably mechanically defibrated biomass nanofibers.

[0024] Commercially available biomass nanofibers may be used, such as BiNFi-s (registered trademark) manufactured by Sugino Machine Ltd., Cellenpia (registered trademark) manufactured by Nippon Paper Industries Co., Ltd., ELLEX (registered trademark) manufactured by Daio Paper Corporation, and nanoforest (registered trademark) manufactured by Chuetsu Pulp & Paper Co., Ltd.

[0025] In this specification, the term "wood fiber" refers to a general term for lignocellulose fibers.

[0026] Lignocellulosic fibers are produced by mechanically, thermomechanically, biologically, chemically, chemomechanically, or chemothermo-mechanically treating wood or non-wood plant-derived lignocellulosic materials to soften, destroy, loosen, and refine the middle layer that binds the fibers together. Note that lignocellulosic fibers is a general term, and plant fibrous materials that have been subjected to physical, chemical, or biological treatments (e.g., delignification treatment in wood pulping, retting treatment of herbs, etc.) to remove lignin, hemicellulose, etc. are also included in the category of lignocellulosic fibers.

[0027] The lignocellulose fibers may be any of those listed above without any particular limitations. The wood may be either softwood or hardwood. Examples of non-wood plant-derived lignocellulose fibers include straw pulp, bagasse pulp, reed pulp, kenaf pulp, linen pulp, ramie pulp, hemp pulp, flax pulp, and bamboo pulp.

[0028] As the lignocellulose fiber, for example, lignocellulose powder, kraft pulp, semi-chemical pulp, chemi-ground pulp, refiner ground pulp, thermomechanical pulp, groundwood pulp, dissolving pulp, mechanical pulp, fiberboard fibers, etc. can be preferably used.

[0029] Fiberboard fibers are thermomechanical pulp in a broad sense, and in a narrow sense, they are relatively coarse fibers. As an example of the physical form of the fibers, thermomechanical pulp can have a diameter of about 30 μm and a length of about 2 to 3 mm. Such lignocellulosic fibers may be used alone or in combination of two or more types.

[0030] As a method for converting lignocellulose material into lignocellulose fibers, any known method can be used without any particular restrictions. For example, conventional methods for producing pulp, conventional methods for producing fibers for fiberboard, etc. can be used as appropriate.

[0031] One example of a method for converting lignocellulose material into lignocellulose fibers is to crush the lignocellulose material into chips, then steam it using a preheater or a presteamer under pressure of about 1 to 10 bar to soften the lignin and hemicellulose, which are the components of the lignocellulose material, and then defibrate it into fibers or fiber bundles using a disc-type blade while applying pressure in a pressurized refiner to produce the desired fibers.

[0032] Wood flour is mainly wood flour obtained by finely crushing wood, such as cypress, cedar, pine, Japanese larch, fir, birch, maple, ash, oak, beech, persimmon, cherry, hornbeam, camellia, Chinese linden, chestnut, horse chestnut, poplar, magnolia, beech, Japanese hemlock, Douglas fir, maple, alder, rubber tree, ramin, lauan, terentang, mango, rengas, lansinboku, chachinchondoki, sumac, lacquer tree, hazel, alder, birch, asada, catalpa, tabebuya, ebe, gayakan, corzia, canarywood, canarium, katsura, terminalia, idigbo, afara, erima, mersawa, parosapis, chengal, lesak, apitong, kruin, yang, chu Examples of trees that can be used include tail, dona, kapur, yakar, meranti, upna, persimmon, ebony, butabuta, chestnut, bintangor, Santa Maria, calophyllum, gelongan, garcinia, maniil, racemosum, walnut, walnut tree, camphor tree, Queensland walnut, villian, thunbergia persica, greenheart acacia, coccolojua, African teak, afzelia, silk tree, akure, albizia, black locust, magnolia, magnolia, torreya, mulberry, eucalyptus, plane tree, rowan, poplar, sambar oak, zelkova, elm, teak, maphogany, ginkgo, Abies sachalinensis, larch, yew, and torreya.

[0033] The size of the plant-derived filler (C) is preferably 5000 μm or less, more preferably 3000 μm or less, even more preferably 1000 μm or less, and particularly preferably 200 μm or less.

[0034] When the plant-derived filler (C) is wood fiber, the width of the wood fiber is preferably 1 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less. The length of the wood fiber is preferably 0.1 mm or more and 50 mm or less, more preferably 1 mm or more and 5 mm or less. The length and width of such fibers can be adjusted to the desired length and width by adjusting operating conditions such as the spacing between the refiner disks.

[0035] When a bundle solidified with an adhesive such as a fiber bundling agent is used as the plant-derived filler (C), the width of the bundle is preferably 0.01 mm to 50 mm, more preferably 0.1 mm to 40 mm, and the length of the bundle is preferably 0.5 mm to 20 mm, more preferably 1 mm to 10 mm.

[0036] The plant-derived filler (C) can be obtained, for example, by treating at least one raw material selected from the group consisting of woods, pulps, papers, plant stems or leaves, and plant shells using a grinder.

[0037] Among the plant-derived fillers (C), cellulose fibers can be obtained, for example, by the following method. Wood, one of the above-mentioned cellulose raw materials, is coarsely pulverized using a cutting machine such as a shredder, as necessary. The coarsely pulverized wood is then processed or dried using an impact pulverizer or extruder. The processed cellulose raw material is then agitated using a media pulverizer to obtain cellulose fibers.

[0038] The plant-derived filler (C) may contain acetaldehyde as a VOC in an amount of 0.01 ppm or more and 5.00 ppm or less, or 0.01 ppm or more and 1.00 ppm or less.

[0039] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits a relatively small amount of VOCs, the content of the plant-derived filler (C) is 20% by mass or more and 91% by mass or less, preferably 40% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 70% by mass or less, where the total content of the (C) and (D) is 100% by mass. Note that when the resin composition contains two or more types of plant-derived fillers (C), the content of the plant-derived fillers (C) is the total content thereof.

[0040] [Hydrophilic resin (D) having hydroxyl groups] Examples of the hydrophilic resin (D) having hydroxyl groups include polyvinyl alcohol, polyethylene oxide, polyethylene glycol, polyglycerin, etc. Among these, from the viewpoint of obtaining a molded article having relatively excellent tensile strength, the hydrophilic resin (D) having hydroxyl groups is preferably polyvinyl alcohol, polyethylene oxide, or polyethylene glycol, more preferably polyvinyl alcohol. Note that the resin composition may contain only one type of hydrophilic resin (D) having hydroxyl groups, or may contain two or more types.

[0041] Polyvinyl alcohol is a water-soluble polymer obtained as a hydrolysis (saponification) product of vinyl acetate. Examples of polyvinyl alcohol include various polyvinyl alcohols such as low-saponification products, partially saponified products, and fully saponified products. Examples of polyvinyl alcohol include various polyvinyl alcohols such as polyvinyl alcohols having functional groups such as carboxylic acid, sulfonic acid, quaternary ammonium salt, polyethylene oxide group, and acetoacetyl group; and copolymer polyvinyl alcohols of ethylene, butene, butenediol, etc.

[0042] The degree of polymerization of the polyvinyl alcohol is preferably 100 or more and 1,000 or less, more preferably 100 or more and 600 or less, from the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC.

[0043] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits a relatively small amount of VOCs, the degree of saponification of the polyvinyl alcohol is preferably 10 or more and 90 or less, more preferably 30 or more and 90 or less, and even more preferably 50 or more and 80 or less.

[0044] In one embodiment of the resin composition according to the present embodiment, the hydrophilic resin (D) having a hydroxyl group is polyvinyl alcohol having a degree of polymerization of 100 or more and 1,000 or less and a degree of saponification of 10 or more and 90 or less.

[0045] The degree of saponification and degree of polymerization of polyvinyl alcohol can be measured in accordance with JIS K6726-1994. The values ​​of the degree of saponification and degree of polymerization of polyvinyl alcohol measured by this method provided by the manufacturer may be used.

[0046] As the polyvinyl alcohol, commercially available products may be used, such as Denka Poval manufactured by Denka Co., Ltd., Kuraray Poval manufactured by Kuraray Co., Ltd., JMR manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., and Poval manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.

[0047] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC, the content of the hydrophilic resin (D) having a hydroxyl group is 9% by mass or more and 80% by mass or less, preferably 20% by mass or more and 60% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, where the total content of the (C) and (D) is 100% by mass. Note that when the resin composition contains two or more types of hydrophilic resins (D) having a hydroxyl group, the content of the hydrophilic resins (D) having a hydroxyl group is the total content thereof.

[0048] [Other Additives] The resin composition according to the present embodiment may contain other additives as needed. Examples of the other additives include pigments, dyes, inorganic fillers, neutralizing agents, antioxidants, lubricants, copper inhibitors, antifogging agents, antistatic agents, processing stabilizers, UV absorbers, light stabilizers, nucleating agents, clarifying nucleating agents, processing aids, metal soaps, foaming agents, antibacterial agents, plasticizers, flame retardants, flame retardant aids, crosslinking agents, crosslinking aids, brightness enhancers, flowability modifiers, and crystallization retarders.

[0049] 2. Method for Producing Resin Composition The method for producing a resin composition according to this embodiment is a method for producing the above-described resin composition, and includes a step of kneading the plant-derived filler (C) and the hydrophilic resin (D) having a hydroxyl group using a kneader.

[0050] Examples of the kneading method include melt kneading, solid phase shear continuous kneading, etc. Among these, the kneading method is preferably melt kneading.

[0051] Examples of kneaders used for the kneading include a single-screw extruder, a twin-screw extruder, a Banbury mixer, a heat roll, a Laboplastomill, etc. Among these, the kneader is preferably a single-screw extruder, a twin-screw extruder, a Banbury mixer, or a Laboplastomill, and more preferably a twin-screw extruder, a Banbury mixer, or a Laboplastomill.

[0052] The kneading temperature is preferably 160°C or higher and 230°C or lower, and more preferably 170°C or higher and 200°C or lower.

[0053] In the kneading, the rotation speed of the screw provided in the kneader is preferably 50 rpm or more and 500 rpm or less, more preferably 100 rpm or more and 500 rpm or less, and even more preferably 100 rpm or more and 300 rpm or less.

[0054] The kneading time is preferably 1 minute or more and 15 minutes or less.

[0055] The components may be kneaded simultaneously or sequentially.

[0056] The method for producing the resin composition according to this embodiment is carried out, for example, by the following method.

[0057] The hydrophilic resin (D) having hydroxyl groups is supplied to a kneader (for example, Labo Plastomill manufactured by Toyo Seiki Seisakusho, etc.), and then the plant-derived filler (C) is supplied to the kneader. The mixture is melt-kneaded for 5 minutes at a temperature of 180°C and a rotation speed of 100 rpm to obtain a resin composition.

[0058] 3. Polyolefin Resin Composition The polyolefin resin composition according to this embodiment contains a polyolefin resin (A), a modified polyolefin resin (B), a plant-derived filler (C), and a hydrophilic resin having a hydroxyl group (D).

[0059] [Polyolefin Resin (A)] The polyolefin resin (A) is a resin containing an olefin polymer. In this specification, the polyolefin resin (A) refers to an unmodified polyolefin resin.

[0060] Examples of the polyolefin resin (A) include polyethylene resins, polypropylene resins, etc. Among these, the polyolefin resin (A) is preferably a polypropylene resin from the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC.

[0061] <Polypropylene Resin> The polypropylene resin is a resin containing a propylene polymer.

[0062] A propylene-based polymer is a polymer containing more than 50% by mass of monomer units derived from propylene. Examples of propylene-based polymers include propylene homopolymers, random copolymers of propylene and monomers other than propylene, and heterophasic propylene polymer materials. A polypropylene-based resin may contain only one type of propylene-based polymer, or may contain two or more types of propylene-based polymers.

[0063] From the viewpoint of improving the rigidity and impact resistance of the molded body, the polypropylene-based resin preferably contains, as a propylene-based polymer, at least one selected from the group consisting of a propylene homopolymer and a heterophasic propylene polymer material, and more preferably contains a heterophasic propylene polymer material.

[0064] The propylene homopolymer can be produced, for example, by carrying out a polymerization step in which propylene is polymerized using a polymerization catalyst.

[0065] Examples of the polymerization catalyst include Ziegler catalysts; Ziegler-Natta catalysts; catalysts containing a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring and an alkylaluminoxane; catalysts containing a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring, a compound that forms an ionic complex upon reaction with the transition metal compound, and an organoaluminum compound; and modified catalysts obtained by supporting a catalyst component (a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring, a compound that forms an ionic complex, an organoaluminum compound, etc.) on inorganic particles (silica, clay mineral, etc.).

[0066] Examples of the polymerization catalyst include those described in JP-A-61-218606, JP-A-5-194685, JP-A-7-216017, JP-A-9-316147, JP-A-10-212319, JP-A-2004-182981, JP-A-2010-168545, and JP-A-2011-246699.

[0067] Furthermore, a polymer obtained by prepolymerizing propylene in the presence of the above polymerization catalyst can also be used as the polymerization catalyst.

[0068] Examples of polymerization methods include bulk polymerization, solution polymerization, and gas phase polymerization. Here, bulk polymerization refers to a method in which polymerization is carried out using an olefin that is liquid at the polymerization temperature as a medium. Solution polymerization refers to a method in which polymerization is carried out in an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, or octane. Gas phase polymerization refers to a method in which gaseous monomers are used as a medium and the gaseous monomers are polymerized in the medium.

[0069] The polymerization method may be, for example, a batch method, a continuous method, or a combination thereof. The polymerization method may be a multi-stage method in which a plurality of polymerization reactors are connected in series.

[0070] From the viewpoint of industrial and economical excellence, the polymerization method is preferably a continuous gas phase polymerization method or a bulk-gas phase polymerization method in which bulk polymerization and gas phase polymerization are carried out continuously.

[0071] Various conditions in the polymerization step (polymerization conditions such as polymerization temperature, polymerization pressure, monomer concentration, catalyst input amount, and polymerization time) may be appropriately determined depending on the molecular structure of the target polymer.

[0072] In the method for producing a propylene homopolymer, other steps may be carried out before or after the polymerization step. For example, after the polymerization step, the polymer may be dried at a temperature equal to or lower than the melting point of the polymer, as necessary, in order to remove residual solvent contained in the polymer and ultralow molecular weight oligomers produced as by-products during production. Examples of drying methods include those described in JP-A-55-75410 and JP-A-2565753.

[0073] The random copolymer of propylene and a monomer other than propylene contains monomer units derived from propylene and monomer units derived from a monomer other than propylene. In the random copolymer, the content of the monomer units derived from a monomer other than propylene is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, relative to the total mass of the copolymer (100% by mass).

[0074] Examples of monomers other than propylene include ethylene and α-olefins having 4 to 12 carbon atoms. In this specification, α-olefins are aliphatic unsaturated hydrocarbons having a carbon-carbon unsaturated double bond at the α-position. Examples of α-olefins having 4 to 12 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0075] The monomer other than propylene is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0076] Examples of random copolymers of propylene and a monomer other than propylene include propylene-ethylene random copolymers, propylene-1-butene random copolymers, propylene-1-hexene random copolymers, propylene-1-octene random copolymers, propylene-ethylene-1-butene random copolymers, propylene-ethylene-1-hexene random copolymers, and propylene-ethylene-1-octene random copolymers.

[0077] A random copolymer of propylene and a monomer other than propylene can be produced, for example, by polymerizing propylene and a monomer other than propylene in accordance with the polymerization catalyst, polymerization method, polymerization system, and polymerization conditions that can be used in the production of the above-mentioned propylene homopolymer.

[0078] The heterophasic propylene polymer material is a mixture containing a polymer I containing monomer units derived from propylene, and a polymer II containing monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms and monomer units derived from propylene.

[0079] The heterophasic propylene polymer material can be produced, for example, by carrying out a first polymerization step of polymerizing polymer I and a second polymerization step of polymerizing polymer II. These polymerization steps can be carried out using the same polymerization catalyst, polymerization method, polymerization system, and polymerization conditions as those usable in the production of the above-mentioned propylene homopolymer.

[0080] The heterophasic propylene polymer material may be such that the sum of polymer I and polymer II contained in the heterophasic propylene polymer material is 100% by mass relative to the total mass of the heterophasic propylene polymer material (100% by mass).

[0081] Polymer I may contain 70% by mass or more of monomer units derived from propylene (where the total mass of Polymer I is 100% by mass). Polymer I may be, for example, a propylene homopolymer, or may contain monomer units derived from a monomer other than propylene. When Polymer I contains monomer units derived from a monomer other than propylene, the content thereof is usually 0.01% by mass or more and 30% by mass or less, relative to the total mass of Polymer I (100% by mass).

[0082] Examples of the monomer other than propylene include ethylene and α-olefins having 4 or more carbon atoms. Examples of the α-olefins having 4 or more carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0083] The monomer other than propylene is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0084] Examples of polymer I containing a monomer unit derived from a monomer other than propylene include a propylene-ethylene copolymer, a propylene-1-butene copolymer, a propylene-1-hexene copolymer, a propylene-1-octene copolymer, a propylene-ethylene-1-butene copolymer, a propylene-ethylene-1-hexene copolymer, and a propylene-ethylene-1-octene copolymer.

[0085] Polymer I is preferably a propylene homopolymer, a propylene-ethylene copolymer, a propylene-1-butene copolymer, or a propylene-1-hexene copolymer, and more preferably a propylene homopolymer.

[0086] The content of polymer I is usually 30% by mass or more and 99% by mass or less, preferably 50% by mass or more and 95% by mass or less, and more preferably 60% by mass or more and 90% by mass or less, based on the total mass of the heterophasic propylene polymerization material (100% by mass).

[0087] As described above, polymer II contains monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, and monomer units derived from propylene. Examples of α-olefins having 4 to 12 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0088] Polymer II preferably contains 30% by mass or more of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, and also contains monomer units derived from propylene (where the total mass of Polymer II is taken as 100% by mass).

[0089] In Polymer II, the content of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms is usually 1% by mass or more and 80% by mass or less, preferably 20% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 60% by mass or less (where the total mass of Polymer II is taken as 100% by mass).

[0090] In Polymer II, the at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, 1-octene, and 1-decene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0091] Examples of polymer II include propylene-ethylene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, propylene-ethylene-1-decene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-1-decene copolymer, etc. Among these, polymer II is preferably a propylene-ethylene copolymer, a propylene-1-butene copolymer, or a propylene-ethylene-1-butene copolymer, and more preferably a propylene-ethylene copolymer.

[0092] The content of polymer II is usually 1% by mass or more and 70% by mass or less, preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less, relative to the total mass (100% by mass) of the heterophasic propylene polymerization material.

[0093] Examples of heterophasic propylene polymer materials include (propylene)-(propylene-ethylene) polymer materials, (propylene)-(propylene-ethylene-1-butene) polymer materials, (propylene)-(propylene-ethylene-1-hexene) polymer materials, (propylene)-(propylene-ethylene-1-octene) polymer materials, (propylene)-(propylene-1-butene) polymer materials, (propylene)-(propylene-1-hexene) polymer materials, (propylene)-(propylene-1-octene) polymer materials, and (propylene)-(propylene- (propylene-ethylene)-(propylene-ethylene) polymerization material, (propylene-ethylene)-(propylene-ethylene-1-butene) polymerization material, (propylene-ethylene)-(propylene-ethylene-1-hexene) polymerization material, (propylene-ethylene)-(propylene-ethylene-1-octene) polymerization material, (propylene-ethylene)-(propylene-ethylene-1-decene) polymerization material, (propylene-ethylene)-(propylene-1-butene) polymerization material, (propylene-ethylene)-(propylene-1-hexene) (propylene-ethylene)-(propylene-1-octene) polymerization material, (propylene-ethylene)-(propylene-1-decene) polymerization material, (propylene-1-butene)-(propylene-ethylene) polymerization material, (propylene-1-butene)-(propylene-ethylene-1-butene) polymerization material, (propylene-1-butene)-(propylene-ethylene-1-hexene) polymerization material, (propylene-1-butene)-(propylene-ethylene-1-octene) polymerization material, (propylene-1-butene)-(propylene-ethylene- (propylene-1-decene) polymerization material, (propylene-1-butene)-(propylene-1-butene) polymerization material, (propylene-1-butene)-(propylene-1-hexene) polymerization material, (propylene-1-butene)-(propylene-1-octene) polymerization material, (propylene-1-butene)-(propylene-1-decene) polymerization material, (propylene-1-hexene)-(propylene-1-hexene) polymerization material, (propylene-1-hexene)-(propylene-1-octene) polymerization material, (propylene-1-hexene)-(propylene-1-decene) polymerization material,Examples include (propylene-1-octene)-(propylene-1-octene) polymer materials, (propylene-1-octene)-(propylene-1-decene) polymer materials, etc.

[0094] Here, the expression "(propylene)-(propylene-ethylene) polymer material" means "a heterophasic propylene polymer material in which polymer I is a propylene homopolymer and polymer II is a propylene-ethylene copolymer." The same applies to other similar expressions.

[0095] The heterophasic propylene polymeric material is preferably a (propylene)-(propylene-ethylene) polymeric material, a (propylene)-(propylene-ethylene-1-butene) polymeric material, a (propylene-ethylene)-(propylene-ethylene) polymeric material, a (propylene-ethylene)-(propylene-ethylene-1-butene) polymeric material, or a (propylene-1-butene)-(propylene-1-butene) polymeric material, and more preferably a (propylene)-(propylene-ethylene) polymeric material.

[0096] From the viewpoint of improving the molding processability of the polypropylene resin composition, the melt flow rate (MFR) of the propylene polymer is preferably 1 g / 10 min or more and 300 g / 10 min or less, and more preferably 10 g / 10 min or more and 200 g / 10 min or less.

[0097] The melt flow rate (MFR) of the propylene polymer is measured by Method A under conditions of a temperature of 230°C and a load of 2.16 kg in accordance with the method specified in JIS K7210-1:2014 and K7210-2:2014.

[0098] <Polyethylene Resin> The polyethylene resin is a resin containing an ethylene polymer.

[0099] An ethylene-based polymer is a polymer containing more than 50% by mass of monomer units derived from ethylene. Examples of ethylene-based polymers include ethylene homopolymers, copolymers of ethylene and α-olefins, and copolymers of ethylene and α-olefins substituted with an alicyclic compound. The ethylene-based polymer may also be a mixture of an ethylene homopolymer and a copolymer of ethylene and α-olefins. The amount of monomer units derived from α-olefins in the ethylene-based polymer is not particularly limited and may be, for example, 4.0% by mass or more and 20% by mass or less.

[0100] Examples of ethylene homopolymers include high-pressure low-density polyethylene (LDPE), which is produced by high-pressure radical polymerization using a radical initiator. High-pressure low-density polyethylene (LDPE) is a polymer in which repeating ethylene units are randomly bonded to form a branched structure. High-pressure low-density polyethylene (LDPE) has a density of, for example, 910 to 935 kg / m ３ may be.

[0101] Examples of the copolymer of ethylene and an α-olefin include linear low-density polyethylene having crystallinity, and elastomers of copolymers of ethylene and an α-olefin having low crystallinity and rubber-like elastic properties.

[0102] The density of the linear low-density polyethylene is, for example, 900 to 940 kg / m ３ The density of the elastomer of the copolymer of ethylene and α-olefin may be, for example, 860 to 900 kg / m ３ may be.

[0103] Examples of the α-olefin include α-olefins having 3 to 10 carbon atoms. Examples of the α-olefins having 3 to 10 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 3-methyl-1-butene. Preferred are α-olefins having 4 to 10 carbon atoms, and more preferred are 1-butene, 1-hexene, and 1-octene.

[0104] Examples of copolymers of ethylene and α-olefins include ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, ethylene-1-decene copolymers, ethylene-(3-methyl-1-butene) copolymers, etc. The copolymer of ethylene and α-olefins may be one of these copolymers alone or a mixture of two or more thereof.

[0105] Examples of α-olefins substituted with alicyclic compounds include vinylcyclohexane.

[0106] The melt flow rate (MFR) of the ethylene polymer is preferably 0.5 g / 10 min or more and 50 g / 10 min or less, more preferably 1 g / 10 min or more and 30 g / 10 min or less, and even more preferably 1 g / 10 min or more and 20 g / 10 min or less.

[0107] The melt flow rate (MFR) of the ethylene polymer is measured by Method A under conditions of a temperature of 190°C and a load of 2.16 kg in accordance with the method specified in JIS K7210-1:2014 and K7210-2:2014.

[0108] The ethylene polymer can be produced by a known polymerization method using a known polymerization catalyst.

[0109] Examples of the polymerization catalyst include homogeneous catalyst systems typified by metallocene catalysts, Ziegler catalyst systems, Ziegler-Natta catalyst systems, etc. Examples of homogeneous catalyst systems include a catalyst system comprising a Group 4 transition metal compound having a cyclopentadienyl ring and an alkylaluminoxane, a catalyst system comprising a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that reacts with the metal compound to form an ionic complex, and an organoaluminum compound, a catalyst system in which inorganic particles such as silica or a clay mineral are supported and modified with catalytic components such as a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that forms an ionic complex, and an organoaluminum compound, and a prepolymerization catalyst system prepared by prepolymerizing ethylene or an α-olefin in the presence of the above catalyst system.

[0110] Furthermore, a radical initiator can be used as a polymerization catalyst for high-pressure low-density polyethylene (LDPE).

[0111] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC, the content of the polyolefin resin (A) is 1% by mass or more and 96.4% by mass or less, preferably 20% by mass or more and 90% by mass or less, more preferably 25% by mass or more and 80% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less, where the total content of the polyolefin resins (A), (B), (C), and (D) is taken as 100% by mass. Note that when the polyolefin resin (A) is a combination of two or more types, the content of the polyolefin resin (A) is the total content thereof.

[0112] [Modified Polyolefin Resin (B)] The modified polyolefin resin (B) is a resin containing a modified polyolefin polymer.

[0113] Examples of the modified polyolefin resin (B) include modified polyethylene resins, modified polypropylene resins, etc. Among these, the modified polyolefin resin (B) is preferably a modified polypropylene resin from the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC.

[0114] Examples of modified polyolefin polymers include acid-modified polyolefin polymers, hydroxyl-modified polyolefin polymers, epoxy-modified polyolefin polymers, carbodiimide-modified polyolefin polymers, amine-modified polyolefin polymers, acrylic-modified polyolefin polymers, and polyoxyethylene-modified polyolefin polymers. Among these, from the viewpoint of obtaining a molded article having relatively excellent tensile strength while containing a plant-derived filler, the modified polyolefin polymer is preferably at least one selected from the group consisting of acid-modified polyolefin polymers, hydroxyl-modified polyolefin polymers, epoxy-modified polyolefin polymers, carbodiimide-modified polyolefin polymers, amine-modified polyolefin polymers, and acrylic-modified polyolefin polymers, and more preferably at least one selected from the group consisting of acid-modified polyolefin polymers, hydroxyl-modified polyolefin polymers, epoxy-modified polyolefin polymers, and carbodiimide-modified polyolefin polymers. The modified polyolefin resin (B) may contain only one type of modified polyolefin polymer, or may contain two or more types. In one aspect of the polyolefin resin composition of the present embodiment, the modified polyolefin resin (B) includes at least one selected from the group consisting of acid-modified polyolefin polymers, hydroxyl group-modified polyolefin polymers, epoxy-modified polyolefin polymers, and carbodiimide-modified polyolefin polymers.

[0115] The acid-modified polyolefin polymer is shown in the following (1) or (2), namely, it has a monomer unit (modifying group) derived from at least one of an unsaturated carboxylic acid and its derivative. (1) A product obtained by grafting or terminally reacting at least one of an unsaturated carboxylic acid or its derivative with an olefin homopolymer identical or different from the above-mentioned olefin polymer, at least two kinds of olefin copolymers, or a block copolymer obtained by homopolymerizing an olefin and then copolymerizing at least two kinds of olefins. (2) A product obtained by copolymerizing at least one kind of olefin with at least one of an unsaturated carboxylic acid and its derivative.

[0116] Examples of unsaturated carboxylic acids include maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid. Derivatives of unsaturated carboxylic acids include unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, and dimethyl fumarate; unsaturated carboxylic acid amides such as acrylamide, methacrylamide, monoamide maleate, diamide maleate, and monoamide fumarate; unsaturated carboxylic acid imides such as maleimide and N-butylmaleimide; and unsaturated carboxylic acid metal salts such as sodium methacrylate. The unsaturated carboxylic acid may be produced by dehydrating citric acid, malic acid, or the like in the step of grafting to a polyolefin. At least one of the unsaturated carboxylic acid and its derivative is preferably maleic anhydride, glycidyl acrylate, or glycidyl methacrylate.

[0117] The acid-modified polyolefin polymer is, as one embodiment, shown in (1') or (2') below. (1') A product obtained by grafting or terminally reacting maleic anhydride with an olefin polymer containing 70% by mass or more, preferably 80% by mass or more, of monomer units derived from at least one olefin selected from ethylene and propylene. (2') A product obtained by copolymerizing at least one olefin selected from ethylene and propylene with a glycidyl methacrylic acid ester or maleic anhydride.

[0118] Examples of acid-modified polyolefin polymers include maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, maleic acid-modified polypropylene, itaconic acid-modified polypropylene, methacrylic acid-modified polypropylene, glycidyl acrylate-modified polypropylene, glycidyl methacrylate-modified polypropylene, etc. Among these, the acid-modified polyolefin polymer is preferably maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, maleic acid-modified polypropylene, itaconic acid-modified polypropylene, glycidyl acrylate-modified polypropylene, or glycidyl methacrylate-modified polypropylene, more preferably maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, maleic acid-modified polypropylene, glycidyl acrylate-modified polypropylene, or glycidyl methacrylate-modified polypropylene.

[0119] The hydroxyl group-modified polyolefin polymer is similar to the acid-modified polyolefin polymer, except that the "unsaturated carboxylic acid and / or its derivative" shown in (1) or (2) above is replaced with "unsaturated alcohol or unsaturated carboxylic acid ester having a hydroxyl group." In other words, the hydroxyl group-modified polyolefin polymer has a monomer unit (modifying group) derived from an unsaturated alcohol or an unsaturated carboxylic acid ester having a hydroxyl group.

[0120] Examples of unsaturated alcohols include allyl alcohol, crotyl alcohol, methyl vinyl carbinol, allyl carbinol, methylpropipenyl carbinol, 4-penten-1-ol, 10-undecen-1-ol, propargyl alcohol, 1,4-pentadiene-3-ol, 1,4-hexadiene-3-ol, 3,5-hexadiene-2-ol, 2,4-hexadiene-1-ol, 3-butene-1,2-diol, 2,5-dimethyl-3-hexene-2,5-diol, 1,5-hexadiene-3,4-diol, 2,6-octadiene-4,5-diol, etc. Among these, the unsaturated alcohol is preferably allyl alcohol or allyl carbinol.

[0121] Examples of the unsaturated carboxylic acid ester having a hydroxyl group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl acrylate.

[0122] Examples of hydroxyl group-modified polyolefin polymers include ethylene-allyl alcohol copolymer, ethylene-crotyl alcohol copolymer, ethylene-methylvinylcarbinol copolymer, ethylene-allylcarbinol copolymer, ethylene-4-penten-1-ol copolymer, ethylene-10-undecen-1-ol copolymer, propylene-allyl alcohol copolymer, propylene-crotyl alcohol copolymer, propylene-methylvinylcarbinol copolymer, propylene-allylcarbinol copolymer, propylene-4-penten-1-ol copolymer, propylene-10-undecen-1-ol copolymer, 2-hydroxyethyl methacrylate-modified polypropylene, 2-hydroxypropyl methacrylate-modified polypropylene, 4-hydroxybutyl acrylate-modified polypropylene, 2-hydroxyethyl methacrylate-modified polyethylene, 2-hydroxypropyl methacrylate-modified polyethylene, and 4-hydroxybutyl acrylate-modified polyethylene. Among these, the hydroxyl group-modified polyolefin polymer is preferably a propylene-4-penten-1-ol copolymer, a propylene-10-undecen-1-ol copolymer, a 2-hydroxyethyl methacrylate-modified polypropylene, or a 4-hydroxybutyl acrylate-modified polypropylene, and more preferably a 2-hydroxyethyl methacrylate-modified polypropylene or a 4-hydroxybutyl acrylate-modified polypropylene.

[0123] The hydroxyl group-modified polyolefin polymer can also be produced by converting a functional group introduced using a chain transfer agent during polymerization, or by converting a functional group introduced to a terminal double bond of a polyolefin polymer, and the hydroxyl group may be introduced by any method.

[0124] The position of the hydroxyl group in the hydroxyl group-modified polyolefin polymer is not particularly limited, and the hydroxyl group may be modified in the polyolefin chain with hydroxyl groups, modified with hydroxyl groups at both ends, or modified with hydroxyl groups at one end. Furthermore, the positions of the hydroxyl groups may be any combination of the above.

[0125] The epoxy-modified polyolefin polymer is similar to the acid-modified polyolefin polymer except that the "unsaturated carboxylic acid and at least one of its derivatives" shown in (1) or (2) above is replaced with an "unsaturated epoxy compound," i.e., it has a monomer unit (modifying group) derived from an unsaturated epoxy compound.

[0126] Examples of unsaturated epoxy compounds include glycidyl acrylate, glycidyl methacrylate, itaconic acid glycidyl ester, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether, etc. Among these, the unsaturated epoxy compound is preferably glycidyl acrylate or glycidyl methacrylate.

[0127] Examples of epoxy-modified polyolefin polymers include ethylene-glycidyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-methyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-ethyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-normal propyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-isopropyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-normal butyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-isobutyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-2-ethylhexyl (meth)acrylate copolymer, ethylene-glycidyl (meth)acrylate-vinyl acetate copolymer, glycidyl (meth)acrylate-modified polyethylene, glycidyl (meth)acrylate-modified polypropylene, and the like. Among these, the epoxy-modified polyolefin polymer is preferably an ethylene-glycidyl (meth)acrylate copolymer, a glycidyl (meth)acrylate-modified polyethylene, or a glycidyl (meth)acrylate-modified polypropylene, and more preferably an ethylene-glycidyl (meth)acrylate copolymer or a glycidyl (meth)acrylate-modified polypropylene.

[0128] The epoxy-modified polyolefin polymer may be obtained by reacting a polyolefin having a group reactive with an epoxy group with an epoxy group-containing compound, for example, by melt-kneading the two.

[0129] For producing an epoxy-modified polyolefin polymer, various methods can be used, such as those described in "Practical Polymer Alloy Design" (by Ide Fumio, Kogyo Chosakai (1996)) and Prog. Polym. Sci., 24, 81-142 (1999). That is, any of the solution method, bulk method, and melt-kneading method may be used. Furthermore, these methods may be used in combination.

[0130] A polyolefin having a group reactive with an epoxy group can be obtained by introducing a compound reactive with an epoxy group into a polyolefin.

[0131] Examples of compounds that react with epoxy groups include compounds having a group with active hydrogen that is reactive with epoxy groups, and specific examples include compounds having a group derived from carboxylic acid, amine, phenol, thiol, etc. Among these, the compound that reacts with epoxy groups is preferably a compound having a group derived from carboxylic acid, and more preferably an unsaturated carboxylic acid or a derivative thereof. The compound that reacts with epoxy groups may be used alone or in combination of two or more.

[0132] Examples of unsaturated carboxylic acids include unsaturated compounds having one or more carboxylic acid groups and unsaturated compounds having one or more carboxylic acid anhydride groups. Examples of unsaturated groups in unsaturated carboxylic acids include vinyl groups, vinylene groups, and unsaturated cyclic hydrocarbon groups. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid. Examples of derivatives of unsaturated carboxylic acids include unsaturated carboxylic anhydrides, unsaturated carboxylic acid halides, unsaturated carboxylic acid amides, unsaturated carboxylic acid imides, and unsaturated carboxylic acid esters. Examples of the derivatives of unsaturated carboxylic acids include malenyl chloride, malenylimide, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalate, dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, aminoethyl methacrylate, and aminopropyl methacrylate.

[0133] Among these, the unsaturated carboxylic acid or its derivative is preferably maleic anhydride, (meth)acrylic acid, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride, hydroxyethyl(meth)acrylate, or aminopropyl methacrylate, more preferably maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, or bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride. That is, the compound that reacts with an epoxy group is particularly preferably maleic anhydride.

[0134] Various methods can be used to introduce a compound reactive with an epoxy group into a polyolefin. Examples of such methods include a method of grafting or terminally reacting a compound reactive with an epoxy group onto the polyolefin main chain, and a method of radically copolymerizing an olefin such as ethylene or propylene with a compound reactive with an epoxy group.

[0135] The epoxy group-containing compound is preferably a polyepoxide having a repeating unit represented by the following general formula (i).

[0136] (In formula (i), R Ｅ１ represents a divalent organic group, and R Ｅ２ and R Ｅ３ are each independently a monovalent organic group, and the asymmetric carbon atom may have any configuration provided that it does not contradict the epoxide structure.

[0137] A monoepoxide may be added to the epoxy group-containing compound, and it is also possible to use a single epoxy group-containing compound or a mixture of a plurality of epoxy group-containing compounds.

[0138] It is also possible to use commercially available epoxy group-containing compounds as they are, such as TEPIC-S, TEPIC-L, and TEPIC-HP manufactured by Nissan Chemical Industries, Ltd.

[0139] Examples of epoxy-modified polyolefins obtained by reacting a polyolefin having a group reactive with an epoxy group with an epoxy group-containing compound include a reaction product of maleic anhydride-modified polyethylene with TEPIC-S and a reaction product of maleic anhydride-modified polypropylene with TEPIC-S, and preferably a reaction product of maleic anhydride-modified polypropylene with TEPIC-S.

[0140] The carbodiimide-modified polyolefin polymer can be obtained by reacting a polyolefin having a group reactive with a carbodiimide group with a carbodiimide group-containing compound, specifically by melt-kneading the two.

[0141] For producing a carbodiimide-modified polyolefin polymer, various methods can be used, such as those described in "Practical Polymer Alloy Design" (by Ide Fumio, Kogyo Chosakai (1996)) and Prog. Polym. Sci., 24, 81-142 (1999). That is, any of the solution method, bulk method, and melt-kneading method may be used. Furthermore, these methods may be used in combination.

[0142] A polyolefin having a group reactive with a carbodiimide group can be obtained by introducing a compound reactive with a carbodiimide group into a polyolefin.

[0143] Examples of compounds that react with carbodiimide groups include compounds having a group containing active hydrogen that is reactive with carbodiimide groups, specifically compounds having a group derived from carboxylic acid, amine, alcohol, thiol, etc. Among these, compounds that react with carbodiimide groups are preferably compounds having a group derived from carboxylic acid, more preferably unsaturated carboxylic acid or a derivative thereof. Furthermore, as compounds that react with carbodiimide groups, in addition to compounds having a group containing active hydrogen, compounds having a group that can be easily converted into a group containing active hydrogen by water or the like can also be preferably used, specifically compounds having an epoxy group or a glycidyl group. Note that the compounds that react with carbodiimide groups may be used alone or in combination of two or more.

[0144] Examples of unsaturated carboxylic acids include unsaturated compounds having one or more carboxylic acid groups and unsaturated compounds having one or more carboxylic acid anhydride groups. Examples of unsaturated groups in unsaturated carboxylic acids include vinyl groups, vinylene groups, and unsaturated cyclic hydrocarbon groups. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid. Examples of derivatives of unsaturated carboxylic acids include unsaturated carboxylic anhydrides, unsaturated carboxylic acid halides, unsaturated carboxylic acid amides, unsaturated carboxylic acid imides, and unsaturated carboxylic acid esters. Examples of the derivatives of unsaturated carboxylic acids include malenyl chloride, malenylimide, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalate, dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, aminoethyl methacrylate, and aminopropyl methacrylate.

[0145] Among these, the unsaturated carboxylic acid or its derivative is preferably maleic anhydride, (meth)acrylic acid, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride, hydroxyethyl (meth)acrylate, glycidyl methacrylate, or aminopropyl methacrylate, and more preferably maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, or bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride. That is, maleic anhydride is particularly preferred as the compound that reacts with a carbodiimide group.

[0146] Various methods can be used to introduce a compound reactive with a carbodiimide group into a polyolefin. Examples include a method of grafting or terminally reacting a compound reactive with a carbodiimide group onto the polyolefin main chain, and a method of radically copolymerizing an olefin such as propylene with a compound reactive with a carbodiimide group.

[0147] The carbodiimide group-containing compound is preferably a polycarbodiimide having a repeating unit represented by the following general formula (ii): -N=C=N-R １ -...(ii) (In formula (ii), R １ represents a divalent organic group.

[0148] The method for synthesizing polycarbodiimide is not particularly limited, and for example, polycarbodiimide can be synthesized by reacting an organic polyisocyanate in the presence of a catalyst that promotes the carbodiimidization reaction of an isocyanate group.

[0149] A monocarbodiimide may be added to the polycarbodiimide, and it is also possible to use a single carbodiimide group-containing compound or a mixture of multiple carbodiimide group-containing compounds.

[0150] It is also possible to use commercially available carbodiimide group-containing compounds as they are. Examples of commercially available carbodiimide group-containing compounds include Carbodilite (registered trademark) HMV-15CA, Carbodilite (registered trademark) HMV-8CA, and Carbodilite (registered trademark) LA1 manufactured by Nisshinbo Industries, Inc., and Stabaxol (registered trademark) P and Stabaxol (registered trademark) P400 manufactured by Rhein Chemie.

[0151] Examples of carbodiimide-modified polyolefin polymers include a reaction product of maleic anhydride-modified polyethylene and Carbodilite HMV-15CA, a reaction product of maleic anhydride-modified polyethylene and Carbodilite HMV-8CA, a reaction product of maleic anhydride-modified polyethylene and Carbodilite LA1, a reaction product of maleic anhydride-modified polyethylene and Stabacusol P400, a reaction product of maleic anhydride-modified polypropylene and Carbodilite HMV-15CA, a reaction product of maleic anhydride-modified polypropylene and Carbodilite HMV-8CA, a reaction product of maleic anhydride-modified polypropylene and Carbodilite LA1, and a reaction product of maleic anhydride-modified polypropylene and Stabacusol P400. Among these, the carbodiimide-modified polyolefin polymer is preferably a reaction product of maleic anhydride-modified polypropylene and Carbodilite HMV-15CA, a reaction product of maleic anhydride-modified polypropylene and Carbodilite HMV-8CA, or a reaction product of maleic anhydride-modified polypropylene and Carbodilite LA1, and more preferably a reaction product of maleic anhydride-modified polypropylene and Carbodilite HMV-15CA.

[0152] From the viewpoint of mechanical strength such as impact strength, fatigue properties, and rigidity, the modifying group content of the modified polyolefin resin (B) is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 6% by mass or less, even more preferably 0.1% by mass or more and 5% by mass or less, and particularly preferably 0.1% by mass or more and 1% by mass or less. Furthermore, when the modified polyolefin resin (B) contains a modified polypropylene polymer obtained by a graft reaction or a terminal reaction, the modifying group content of the modified polyolefin resin (B) is preferably 0.1% by mass or more and 5% by mass or less. When the modified polyolefin resin (B) contains a modified polyolefin polymer obtained by copolymerization, the modifying group content of the modified polyolefin resin (B) is preferably 0.1% by mass or more and 5% by mass or less.

[0153] The intrinsic viscosity ([η]) of the modified polyolefin polymer is preferably 0.1 dl / g or more and 3.0 dl / g or less, more preferably 0.1 dl / g or more and 1.0 dl / g or less.

[0154] In this specification, the intrinsic viscosity (unit: dl / g) is a value measured at a temperature of 135° C. using tetralin as a solvent by the following method.

[0155] Using an Ubbelohde viscometer, the reduced viscosity is measured at three concentrations: 0.1 g / dl, 0.2 g / dl, and 0.5 g / dl. The reduced viscosity is plotted against the concentration, and the intrinsic viscosity is calculated by extrapolation, extrapolating the concentration to zero. The method for calculating the intrinsic viscosity by extrapolation is described, for example, on page 491 of "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Shuppan Co., Ltd. in 1982).

[0156] As a method for producing a modified polyolefin polymer, for example, methods exemplified in "Practical Polymer Alloy Design" (Ide Fumio, Kogyo Chosakai (1996)), Prog. Polym. Sci., 24, 81-142 (1999), JP-A 2002-308947, etc. can be used. Furthermore, as a method for producing a modified polyolefin polymer, any of methods such as a solution method, a bulk method, and a melt-kneading method can be used. Furthermore, as a method for producing a modified polyolefin polymer, these methods can be combined.

[0157] The modified polyolefin polymer may be a commercially available product. Examples of commercially available modified polyolefin polymers include UMEX (registered trademark) manufactured by Sanyo Chemical Industries, Ltd., TOYOTAC (registered trademark) manufactured by Toyobo Co., Ltd., TAFUMER M (registered trademark) manufactured by Mitsui Chemicals, Inc., ADMER (registered trademark) manufactured by Mitsui Chemicals, Inc., MODIC (registered trademark) manufactured by Mitsubishi Chemical Corporation, ARROWBASE (registered trademark) manufactured by Unitika Ltd., SUMIFIT (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., and BONDFAST (registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

[0158] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC, the content of the modified polyolefin resin (B) is 1% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, where the total content of the (A), (B), (C) and (D) is 100% by mass. When the modified polyolefin resin (B) contains two or more modified polyolefin polymers, the content of the modified polyolefin resin (B) is the total content thereof.

[0159] [Plant-derived filler (C)] As the plant-derived filler (C), the same plant-derived filler (C) as in the resin composition according to this embodiment can be used.

[0160] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits a relatively low amount of VOCs, the content of the plant-derived filler (C) is 1% by mass or more and 80% by mass or less, preferably 10% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 65% by mass or less, where the total content of the plant-derived fillers (C) is 100% by mass. When the plant-derived filler (C) is a combination of two or more types, the content of the plant-derived filler (C) is the total content.

[0161] [Hydrophilic Resin (D) Having Hydroxyl Groups] As the hydrophilic resin (D) having hydroxyl groups, the same hydrophilic resin (D) having hydroxyl groups as in the resin composition according to this embodiment can be used.

[0162] From the viewpoint of obtaining a molded article that contains a plant-derived filler but emits relatively little VOC, the content of the hydrophilic resin (D) having a hydroxyl group is 1% by mass or more and 30% by mass or less, preferably 1% by mass or more and 25% by mass or less, and more preferably 5% by mass or more and 25% by mass or less, where the total content of the (A), (B), (C), and (D) is 100% by mass. When the hydrophilic resin (D) having a hydroxyl group is a combination of two or more kinds, the content of the hydrophilic resin (D) having a hydroxyl group is the total content.

[0163] [Other Additives] The polyolefin resin composition according to the present embodiment may contain other additives as needed. As the other additives, the same additives as those used in the resin composition according to the present embodiment can be used.

[0164] 4. Method for Producing Polyolefin Resin Composition The method for producing a polyolefin resin composition according to this embodiment is a method for producing the above-mentioned polyolefin resin composition, and includes the following steps 1 and 2. Step 1: A step of kneading the plant-derived filler (C) and the hydrophilic resin (D) having a hydroxyl group using a kneader. Step 2: After step 1, a step of further adding the polyolefin resin (A) and the modified polyolefin resin (B) and kneading them.

[0165] Examples of the kneading method include melt kneading, solid phase shear continuous kneading, etc. Among these, the kneading method is preferably melt kneading.

[0166] Examples of kneaders used for the kneading include a single-screw extruder, a twin-screw extruder, a Banbury mixer, a heat roll, a Laboplastomill, etc. Among these, the kneader is preferably a single-screw extruder, a twin-screw extruder, a Banbury mixer, or a Laboplastomill, and more preferably a twin-screw extruder, a Banbury mixer, or a Laboplastomill.

[0167] The kneading temperature is preferably 160°C or higher and 230°C or lower, and more preferably 170°C or higher and 200°C or lower.

[0168] In the kneading, the rotation speed of the screw provided in the kneader is preferably 50 rpm or more and 500 rpm or less, more preferably 100 rpm or more and 500 rpm or less, and even more preferably 100 rpm or more and 300 rpm or less.

[0169] The kneading time is preferably 1 minute or more and 15 minutes or less.

[0170] In steps 1 and 2, the components may be kneaded simultaneously or sequentially.

[0171] The method for producing the polyolefin resin composition according to this embodiment is carried out, for example, by the following method.

[0172] Step 1: A hydrophilic resin (D) having hydroxyl groups is supplied to a kneader (for example, Labo Plastomill manufactured by Toyo Seiki Seisakusho, etc.), and then a plant-derived filler (C) is supplied to the kneader. The mixture is melt-kneaded for 5 minutes at a temperature of 180°C and a rotation speed of 100 rpm to obtain a resin composition.

[0173] Step 2: The resin composition obtained in Step 1 is crushed using a crusher to obtain a crushed resin composition. The crushed resin composition obtained is uniformly mixed with the modified polyolefin resin composition (B) and the polyolefin resin composition (A) to obtain a mixture. The resulting mixture is fed to a kneader (e.g., a Labo Plastomill manufactured by Toyo Seiki Seisakusho, Ltd.) and melt-kneaded for 5 minutes at a temperature of 180°C and a rotation speed of 100 rpm to obtain a polyolefin resin composition.

[0174] 5. Molded Article The molded article according to this embodiment contains the polyolefin resin composition described above. The molded article is a molded article molded by a conventionally known method. Examples of such molded articles include injection molded articles, press molded articles, vacuum molded articles, vacuum press molded articles, pressure molded articles, foam molded articles, and extrusion molded articles. Examples of methods for molding such molded articles include injection molding, press molding, vacuum molding, vacuum press molding, pressure molding, foam molding, and extrusion molding.

[0175] The molded article according to the present embodiment is preferably an injection-molded article. Examples of the injection molding method for molding the injection-molded article include general injection molding, injection foam molding, supercritical injection foam molding, ultra-high speed injection molding, injection compression molding, injection press molding, gas-assisted injection molding, sandwich molding, sandwich foam molding, and insert-outsert molding.

[0176] Examples of uses of the molded article according to this embodiment include automobile interior / exterior parts, home appliance parts, building materials, miscellaneous goods, furniture, food containers, beverage containers, medical containers, containers, etc. Among these, the use of the molded article is preferably automobile interior / exterior parts or home appliance parts.

[0177] In one aspect, the molded article according to the present embodiment may be obtained by the method described in the following steps 3 and 4. Step 3: A step of pulverizing a molded article containing the polyolefin-based resin composition to obtain a pulverized product. Step 4: A step of molding the pulverized product to obtain a molded article containing the polyolefin-based resin composition.

[0178] The present invention includes the following aspects. [1] A resin composition comprising a plant-derived filler (C) and a hydrophilic resin (D) having hydroxyl groups, wherein the content of the plant-derived filler (C) is 20% by mass or more and 91% by mass or less, and the content of the hydrophilic resin (D) having hydroxyl groups is 9% by mass or more and 80% by mass or less, where the total content of (C) and (D) is 100% by mass. [2] The resin composition according to [1], wherein the hydrophilic resin (D) having hydroxyl groups is polyvinyl alcohol having a degree of polymerization of 100 to 1,000 and a degree of saponification of 10 to 90. [3] A method for producing the resin composition according to [1] or [2], comprising a step of kneading the plant-derived filler (C) and the hydrophilic resin (D) having hydroxyl groups using a kneader. [4] A polyolefin resin composition comprising a polyolefin resin (A), a modified polyolefin resin (B), a plant-derived filler (C), and a hydrophilic resin having hydroxyl groups (D), wherein, where the total content of (A), (B), (C), and (D) is 100% by mass, the content of the polyolefin resin (A) is 1% by mass or more and 96.4% by mass or less, the content of the modified polyolefin resin (B) is 1% by mass or more and 20% by mass or less, the content of the plant-derived filler (C) is 1% by mass or more and 80% by mass or less, and the content of the hydrophilic resin having hydroxyl groups (D) is 1% by mass or more and 30% by mass or less. [5] The polyolefin resin composition according to [4], wherein the polyolefin resin (A) is a polypropylene resin. [6] The polyolefin resin composition according to [4] or [5], wherein the modified polyolefin resin (B) comprises at least one selected from the group consisting of an acid-modified polyolefin polymer, a hydroxyl group-modified polyolefin polymer, an epoxy-modified polyolefin polymer, and a carbodiimide-modified polyolefin polymer. [7] The polyolefin resin composition according to any one of [4] to [6], wherein the hydroxyl group-containing hydrophilic resin (D) is polyvinyl alcohol having a degree of polymerization of 100 to 1,000 and a degree of saponification of 10 to 90. [8] A method for producing the polyolefin resin composition according to any one of [4] to [7], comprising the following steps 1 and 2:Step 1: A step of kneading a plant-derived filler (C) and a hydrophilic resin (D) having a hydroxyl group using a kneader. Step 2: A step of further adding a polyolefin-based resin (A) and a modified polyolefin-based resin (B) and kneading them after Step 1. [9] A molded article comprising the resin composition according to [1] or [2], or the polyolefin-based resin composition according to any one of [4] to [7].

[0179] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples. Furthermore, the operations described below were carried out under normal temperature and pressure conditions unless otherwise specified.

[0180] [Methods for Measuring Physical Properties] (Melt Flow Rate) Measurement was carried out in accordance with JIS K7210-1:2014 and K7210-2:2014 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0181] (Intrinsic Viscosity Number) Using an Ubbelohde viscometer, the reduced viscosity was measured for a plurality of concentrations, the reduced viscosity was plotted against the concentration, and the intrinsic viscosity was determined by the "extrapolation method" in which the concentration was extrapolated to zero. More specifically, the reduced viscosity was measured for three concentrations of 0.1 g / dl, 0.2 g / dl, and 0.5 g / dl using the method described on page 491 of "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Shuppan Co., Ltd. in 1982), and the reduced viscosity was plotted against the concentration, and the intrinsic viscosity number was determined by the method in which the reduced viscosity was extrapolated to zero.

[0182] [Components Used in Examples and Comparative Examples] The components used in the examples and comparative examples are shown below.

[0183] (1) Polyolefin Resin (A) Polypropylene Homopolymer (hPP-1, Noblen HR100EG; manufactured by Sumitomo Chemical Co., Ltd.)

[0184] The physical properties of hPP-1 were as follows: Melt flow rate (temperature 230°C, load 2.16 kg): 23-25 ​​g / 10 min Melting point: 164°C

[0185] (2) Modified polyolefin resin (B) Maleic anhydride-modified polypropylene (MAH-1, maleic anhydride-modified polypropylene obtained by the method described in Synthesis Example 2 of WO 2020 / 009090)

[0186] The physical properties of MAH-1 were as follows: Content of maleic anhydride monomer units contained in MAH-1: 0.3% by mass Intrinsic viscosity: 0.8 dl / g

[0187] (3) Plant-derived filler (C) Wood fiber 1 (NF-1, acetaldehyde content: 0.22 ppm) Lignocellulose fiber for fiberboard produced using a pressure refiner at a fiberboard factory was used as the wood fiber. The fiber length was approximately 3 mm, and the fiber width was approximately 30 μm. Wood fiber 2 (NF-2, acetaldehyde content: 0.38 ppm) Lignocellulose fiber for fiberboard produced using a pressure refiner at a fiberboard factory was solidified with a fiber bundling agent, and then finely cut to obtain a sheet-like bundle. The length of the bundle was approximately 4 mm, and the width of the bundle was approximately 4 mm.

[0188] (4) Hydrophilic resins having hydroxyl groups (D) Polyvinyl alcohol 1 (PVA-1, degree of polymerization 120, degree of saponification 80, JMR-3H; manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) Polyvinyl alcohol 2 (PVA-2, degree of polymerization 250, degree of saponification 80, JMR-10H; manufactured by Nippon Vinyl Acetate & Poval Co., Ltd. JMR-10H) Polyvinyl alcohol 3 (PVA-3, degree of polymerization 250, degree of saponification 65, JMR-10M; manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) Polyvinyl alcohol 4 (PVA-4, degree of polymerization 250, degree of saponification 35, JMR-10L; manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) Polyvinyl alcohol 5 (PVA-5, degree of polymerization 620, degree of saponification 82, JL-05E; manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) Polyvinyl alcohol 6 (PVA-6, polymerization degree 1700, saponification degree 98.5, 28-98; manufactured by Kuraray Co., Ltd.)

[0189] The degrees of polymerization and saponification of PVA-1 to PVA-6 were determined based on information provided by the manufacturers, which were measured in accordance with JIS K6726-1994.

[0190] (5) Other additives Antioxidant 1 (Sumilizer GA80; manufactured by Sumitomo Chemical Co., Ltd.) Antioxidant 2 (Sumilizer GP; manufactured by Sumitomo Chemical Co., Ltd.) Neutralizer (calcium stearate)

[0191] <Resin Composition> (Example 1) 50% by mass of PVA-1, 0.1% by mass of antioxidant 1, 0.1% by mass of antioxidant 2, and 0.05% by mass of a neutralizing agent were mixed to obtain a mixture. The obtained mixture was supplied to a kneader (Labo Plastomill manufactured by Toyo Seiki Seisaku-sho, Ltd.), and then 50% by mass of NF-1 was supplied to the kneader. The mixture was melt-kneaded for 5 minutes at a temperature of 180°C and a rotation speed of 100 rpm to obtain a resin composition.

[0192] The obtained resin composition was preheated at 190° C. for 5 minutes and a pressure of 5 MPa was applied for 3 minutes to obtain a sheet-like press-molded product having a thickness of 300 μm.

[0193] Example 2 A resin composition and a press-molded product were obtained in the same manner as in Example 1, except that 50% by mass of PVA-2 was used instead of PVA-1.

[0194] Example 3 A resin composition and a press-molded product were obtained in the same manner as in Example 1, except that 50% by mass of PVA-3 was used instead of PVA-1.

[0195] Example 4 A resin composition and a press-molded article were obtained in the same manner as in Example 1, except that 50% by mass of PVA-4 was used instead of PVA-1.

[0196] Example 5 A resin composition was obtained in the same manner as in Example 1, except that 50% by mass of PVA-5 and 50% by mass of NF-2 were used instead of PVA-1 and NF-1.

[0197] The obtained resin composition was preheated at 210° C. for 5 minutes and a pressure of 5 MPa was applied for 3 minutes to obtain a sheet-like press-molded product having a thickness of 300 μm.

[0198] Comparative Example 1 An attempt was made to obtain a resin composition in the same manner as in Example 1, except that 50% by mass of PVA-6 was used instead of PVA-1. However, when the mixture was melt-kneaded in a kneader, PVA-6 did not melt and could not be kneaded, and therefore a resin composition and a press-molded product could not be obtained.

[0199] Comparative Example 2 A resin composition and a press-molded article were obtained in the same manner as in Example 1, except that 50% by mass of hPP-1 was used instead of PVA-1.

[0200] Comparative Example 3 A resin composition and a press-molded article were obtained in the same manner as in Example 5, except that 50% by mass of hPP-1 was used instead of PVA-5.

[0201] <Polyolefin-based resin composition> (Example 6) The resin composition obtained in Example 3 was crushed using a crusher to obtain crushed resin composition F-3. 40% by mass of the crushed material F-3, 2% by mass of MAH-1, 58% by mass of hPP-1, 0.1% by mass of antioxidant 1, 0.1% by mass of antioxidant 2, and 0.05% by mass of neutralizing agent 1 were uniformly mixed to obtain a mixture. The obtained mixture was supplied to a kneader (Labo Plastomill, manufactured by Toyo Seiki Seisakusho, Ltd.) and melt-kneaded for 5 minutes under conditions of a temperature of 180°C and a rotation speed of 100 rpm to obtain a polyolefin-based resin composition.

[0202] The resin composition obtained above was preheated at 190° C. for 5 minutes and subjected to a pressure of 5 MPa for 3 minutes to obtain a sheet-like press-molded product having a thickness of 300 μm.

[0203] Comparative Example 4 The resin composition obtained in Comparative Example 2 was crushed using a crusher to obtain a crushed resin composition F-5. A polyolefin resin composition and a press-molded product were obtained in the same manner as in Example 6, except that 50% by mass of the crushed resin F-5 and 78% by mass of hPP-1 were used.

[0204] [Evaluation] <Acetaldehyde Content (Unit: ppm)> The acetaldehyde content (VOC) of the molded articles obtained in Examples 1 to 6 and Comparative Examples 1 to 4 was evaluated. Specifically, approximately 2 g of each molded article obtained in Examples 1 to 6 and Comparative Examples 1 to 4 was cut out, and the resulting test piece was placed in a dedicated sample tube. Using a gas chromatograph (Flash GC Nose Heracles NEO; manufactured by Alpha Moss Japan Co., Ltd.), the acetaldehyde content of the test piece placed in the sample tube was measured under the following conditions: Incubation temperature: 60°C Incubation time: 15 min Injection volume: 5000 μL GC main body Injector temperature: 220°C Trap temperature: 5°C Desorption temperature: 240°C Valve temperature: 260°C Oven: 40°C x 60 s → Heating rate: 2°C / s → 250°C x 60 s Detector: FID; 260°C

[0205] The acetaldehyde content was calculated from the values ​​obtained by the above measurement using a calibration curve prepared from values ​​obtained by measuring an acetaldehyde standard solution in advance.

[0206] Tables 1 and 2 show the formulations of the resin compositions and polyolefin-based resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 4, as well as the evaluation results of the molded articles.

[0207]

[0208]

[0209] From Tables 1 and 2, it can be seen that molded articles that satisfy all of the constituent requirements of the present invention emit relatively small amounts of VOCs, even though they contain plant-derived fillers.

Claims

1. A resin composition comprising a plant-derived filler (C) and a hydrophilic resin (D) having hydroxyl groups, wherein the content of the plant-derived filler (C) is 20% by mass or more and 91% by mass or less, and the content of the hydrophilic resin (D) having hydroxyl groups is 9% by mass or more and 80% by mass or less, where the total content of (C) and (D) is 100% by mass.

2. The resin composition according to claim 1, wherein the hydrophilic resin (D) having a hydroxyl group is a polyvinyl alcohol having a degree of polymerization of 100 or more and 1,000 or less and a degree of saponification of 10 or more and 90 or less.

3. A method for producing the resin composition according to claim 1 or 2, comprising the step of kneading a plant-derived filler (C) and a hydrophilic resin having a hydroxyl group (D) using a kneader.

4. A polyolefin resin composition comprising a polyolefin resin (A), a modified polyolefin resin (B), a plant-derived filler (C), and a hydrophilic resin having a hydroxyl group (D), wherein, assuming the total content of (A), (B), (C) and (D) to be 100% by mass, the content of the polyolefin resin (A) is 1% by mass or more and 96.4% by mass or less, the content of the modified polyolefin resin (B) is 1% by mass or more and 20% by mass or less, the content of the plant-derived filler (C) is 1% by mass or more and 80% by mass or less, and the content of the hydrophilic resin having a hydroxyl group (D) is 1% by mass or more and 30% by mass or less.

5. The polyolefin resin composition according to claim 4, wherein the polyolefin resin (A) is a polypropylene resin.

6. The polyolefin resin composition according to claim 4, wherein the modified polyolefin resin (B) comprises at least one member selected from the group consisting of acid-modified polyolefin polymers, hydroxyl-modified polyolefin polymers, epoxy-modified polyolefin polymers, and carbodiimide-modified polyolefin polymers.

7. The polyolefin resin composition according to claim 4, wherein the hydrophilic resin (D) having a hydroxyl group is a polyvinyl alcohol having a degree of polymerization of 100 or more and 1,000 or less and a degree of saponification of 10 or more and 90 or less.

8. A method for producing the polyolefin resin composition according to any one of claims 4 to 7, comprising the following steps 1 and 2: Step 1: kneading the plant-derived filler (C) and the hydrophilic resin having a hydroxyl group (D) using a kneader; Step 2: after step 1, further adding and kneading the polyolefin resin (A) and the modified polyolefin resin (B).

9. A molded article comprising the resin composition according to claim 1 or 2, or the polyolefin-based resin composition according to any one of claims 4 to 7.

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