Resin material for molding and method for producing the same

Abstract

To provide a resin material for molding that has powdered cellulose and thermoplastic resin uniformly mixed, and exhibits superior strength.SOLUTION: A resin material for molding is provided, which contains 10-90 mass% of powdered cellulose with an average particle diameter of 100 μm or less, and further includes a thermoplastic resin and modified rosin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a molding resin material containing cellulose and a thermoplastic resin, and a method for producing the same. [Background technology]

[0002] Biomass materials are attracting attention as industrial resources. Biomass materials refer to materials derived from living organisms such as plants. Because biomass materials are organic, they emit carbon dioxide when burned. However, the carbon contained in them comes from carbon dioxide absorbed from the atmosphere through photosynthesis during the growth process of the biomass. Therefore, when biomass materials are used, even if they are incinerated, the amount of carbon dioxide emitted over their life cycle is less than that of petrochemical products.

[0003] Against the backdrop of environmental issues such as global warming, there is an urgent need to conserve resources, as well as to promote material recycling, which uses waste as raw materials, and the environmental circulation cycle, typified by biodegradable plastics.In Japan, revised recycling laws and green purchasing laws have been established, and there is a growing demand for products that comply with these laws.

[0004] In this situation, blending biomass materials into resin products, which are widely used from materials for automobile parts to everyday items, will help reduce carbon dioxide emissions throughout their life cycle.

[0005] For example, Patent Document 1 describes a composite material containing carboxylmethylated cellulose nanofibers, a polymer compound having a primary amino group, an acid-modified polyolefin, and a polyolefin. Patent Document 2 describes a cellulose composite material containing wood pulp and a polymer matrix. Patent Document 3 describes a method for producing a wood-flour-containing resin injection-molded product by mixing wood flour and a random polypropylene resin and using an injection molding machine. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 087767 [Patent Document 2] Special Publication No. 2019-512591 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-138337 Summary of the Invention [Problem to be solved by the invention]

[0007] When blending woody biomass with thermoplastic resins such as polypropylene, simply mixing the woody biomass with the thermoplastic resin and heating and melting it can pose problems such as the inability to mix uniformly with polypropylene due to the hydrophilic nature of the woody biomass, and the resulting molded product having low strength.

[0008] To address these problems, for example, Patent Document 1 proposes the use of carboxymethylated cellulose nanofibers as a biomass material. However, the method of Patent Document 1 not only requires carboxymethylated cellulose nanofibers, but also requires the addition of a polymer compound having a primary amino group and an acid-modified polyolefin to improve uniform dispersion in the polyolefin resin, resulting in a significant increase in costs.

[0009] Therefore, an object of the present invention is to provide a molding resin material in which cellulose and a thermoplastic resin are uniformly mixed at low cost. [Means for solving the problem]

[0010] After extensive research into the above-mentioned problems, the present inventors discovered that by using powdered cellulose having a specific average particle size as the cellulose and further blending a specific modified rosin, the cellulose can be uniformly dispersed in a thermoplastic resin, resulting in a molding resin material with excellent moldability. Specifically, the present inventors discovered that an excellent molding resin material can be obtained by blending 10 to 90 mass% of powdered cellulose having an average particle size of 100 μm or less and adding modified rosin containing one or more of rosin glycerin ester, tall oil rosin, polyoxyethylene glycol resin acid ester, and reinforced rosin, thereby completing the present invention.

[0011] The present invention includes, but is not limited to, the following: [1] A molding resin material comprising powdered cellulose having an average particle size of 100 μm or less, a thermoplastic resin, and a modified rosin, wherein the powdered cellulose content is 10 to 90 mass %, and the modified rosin comprises one or more of rosin glycerin ester, tall oil rosin, polyoxyethylene glycol resin acid ester, and reinforced rosin. [2] The molding resin material according to [1], wherein the blending ratio of the powdered cellulose, thermoplastic resin, and modified rosin is 10-90:90-10:0.1-5. [3] The molding resin material according to [1], wherein the powdered cellulose is derived from wood. [4] A method for producing a resin material for a molding die according to any one of [1] to [3], The above method includes a step of heating and kneading powdered cellulose, a thermoplastic resin, and a modified rosin to produce a resin material for a molding die. [5] The method according to [4], wherein in the heating and kneading step, the resin material for the molding die is continuously produced using a twin-screw kneading extruder. [Effects of the Invention]

[0012] According to the present invention, a molding resin material in which cellulose is uniformly dispersed can be efficiently and stably produced. Since the molding resin material according to the present invention has uniformly dispersed cellulose, it is easy to mold, and resin products produced from the molding resin material have excellent strength. DETAILED DESCRIPTION OF THE INVENTION

[0013] In one aspect, the present invention is a molding resin material containing powdered cellulose having an average particle size of 100 μm or less, a thermoplastic resin, and a modified rosin. Modified rosin The molding resin material according to the present invention contains a specific modified rosin (a rosin modification product). The addition of the modified rosin improves the dispersibility of the powdered cellulose, enabling stable production of the molding resin material. The modified rosin also functions as a compatibilizer, improving the strength of the molded product.

[0014] The modified rosin used in the present invention is obtained by chemically modifying rosin. Specific examples include rosin glycerin ester, tall oil rosin, polyoxyethylene glycol resin acid ester, and fortified rosin, which may be used alone or in combination.

[0015] The blending ratio of the modified rosin is preferably 0.1 to 20% by mass, more preferably 0.2 to 10% by mass, and even more preferably 0.3 to 5% by mass of the resin material. The blending ratio of the powdered cellulose, thermoplastic resin, and modified rosin is preferably 10-90:90-10:0.1-20.

[0016] Generally, rosin is a natural resin obtained from plant sap and the like, and is primarily composed of rosin acids such as abietic acid, palustric acid, and isopimaric acid. Modified rosin is a rosin derivative obtained by chemically modifying rosin, and examples include rosin esters, acid-modified rosin, and fortified rosin. The softening point of the modified rosin is not particularly limited, but is, for example, 1 to 200°C, and may be 20 to 160°C or 40 to 120°C, taking into consideration ease of mixing and handling.

[0017] Rosin esters can be produced from rosin and a polyhydric alcohol by a known esterification method, including dihydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylene glycol, tetramethylene glycol, 1,3-butanediol, and 1,6-hexanediol, trihydric alcohols such as glycerin, trimethylolpropane, trimethylolethane, and triethylolethane, tetrahydric alcohols such as pentaerythritol and dipentaerythritol, and amino alcohols such as triethanolamine, tripropanolamine, triisopropanolamine, N-isobutyldiethanolamine, and N-normal butyldiethanolamine.

[0018] Acid-modified rosins obtained by modifying rosin with an acid can be obtained, for example, by reacting rosin with an α,β-unsaturated carboxylic acid. Examples of the α,β-unsaturated carboxylic acid include fumaric acid, maleic acid (anhydride), itaconic acid, citraconic acid (anhydride), acrylic acid, and methacrylic acid.

[0019] Fortified rosin can be obtained, for example, by adding maleic anhydride, fumaric acid, or the like to molten rosin and reacting it to form maleated rosin, which is then saponified with an alkali. Powdered cellulose The powdered cellulose (cellulose powder) used in the present invention can be obtained by pulverizing a cellulose raw material and has an average particle size of 100 μm or less. The powdered cellulose used in the present invention is preferably produced by pulverizing a cellulose raw material that has been subjected to acid hydrolysis, since it contains fewer impurities. However, in the present invention, it may also be produced by mechanically pulverizing a cellulose raw material that has not been subjected to acid hydrolysis.

[0020] The powdered cellulose used in the present invention has an average particle size of 100 μm or less, preferably 1 to 80 μm or 5 to 60 μm, and more preferably 10 to 50 μm. If the average particle size of the powdered cellulose is greater than 100 μm, it may be difficult to uniformly mix it with the resin, and problems such as the resin being shredded when the mixture of pulverized material and resin is injected or transport to a cooling treatment device may occur. The average particle size of the powdered cellulose is the 50% volume average particle size (D50) measured by laser light scattering (laser diffraction) and can be measured using a laser diffraction / scattering particle size distribution analyzer such as the Mastersizer 2000 (manufactured by Malvern Instruments).

[0021] The molding resin material of the present invention can be produced by blending powdered cellulose into a resin. A high blending ratio of powdered cellulose in the molding resin material is preferred to increase the biomass content, but in consideration of the production and strength of the resin material and molded article, the blending ratio is preferably 10 to 90 mass%, more preferably 15 to 60 mass%, and may be 20 to 40 mass%. In the present invention, wood-derived pulp is preferred as the raw material for powdered cellulose. Examples of wood-derived pulp include pulp derived from hardwoods and softwoods, with hardwood-derived chemical pulp being particularly preferred. The pulping method (cooking method) for these wood-derived chemical pulps is not particularly limited, and examples include sulfite cooking, kraft cooking, soda-quinone cooking, and organosolv cooking. Among these, sulfite cooking and kraft cooking are preferred. Examples of chemical pulp include kraft pulp (KP), dissolving kraft pulp (DKP), sulfite pulp (SP), and dissolving sulfite pulp (DSP). Both unbleached and bleached chemical pulp can be used. In addition to chemical pulps, mechanical pulps such as groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), and chemithermomechanical pulp (CTMP) can also be used. As raw materials for the powdered cellulose of the present invention, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood bleached sulfite pulp (LBSP), and softwood bleached sulfite pulp (NBSP) are preferred because of their good grindability. Generally, during the pulping process, lignin, a coloring substance in pulp, is removed by cooking or other methods to whiten the pulp. To further enhance the whiteness of the pulp, a bleaching treatment can be performed. The bleaching method is not particularly limited, and commonly used methods can be used.For example, pulp delignified by conventional methods can be subjected to a combination of chlorine treatment (C), chlorine dioxide bleaching (D), alkaline extraction (E), hypochlorite bleaching (H), hydrogen peroxide bleaching (P), alkaline hydrogen peroxide treatment stage (Ep), alkaline hydrogen peroxide-oxygen treatment stage (Eop), ozone treatment (Z), and chelate treatment (Q), in a sequence such as DE / PD, C / DEHD, ZED-PZ / D-Ep-D, Z / D-Ep-DP, D-Ep-D, D-Ep-DP, D-Ep-PD, Z-Eop-DD, Z / D-Eop-D, or Z / D-Eop-DED (the " / " in the sequence indicates that the treatments before and after " / " are performed consecutively without washing). The brightness of the pulp as a cellulose raw material is preferably 80% or higher based on ISO 2470.

[0022] In one embodiment, powdered cellulose is produced through a process including preparing a slurry from raw pulp, an acid hydrolysis reaction process, a neutralization, washing and deliquor process, a drying process, a pulverization process, and a classification process.

[0023] The slurry preparation step is a step of preparing a slurry from a cellulose raw material such as pulp. The acid hydrolysis reaction step is a step of hydrolyzing a cellulose raw material with acid, for example, by hydrolyzing the cellulose raw material with an acid concentration of 0.10 to 1.0 N to prepare a hydrolysate. The neutralization, washing, and deliquification step is a step of neutralizing the hydrolysate, washing it, and then deliquifying it. The drying step is a step of drying the deliquified hydrolysate to obtain a dried product. The classification step is a step of pulverizing the dried product to obtain a pulverized product. The cellulose powder of the present invention can be produced through these steps.

[0024] When pulp is used as the raw material for the powdery cellulose of the present invention, either fluidized pulp or sheet-like pulp can be used. When fluidized pulp is used as the raw material, the concentration can be increased as necessary before being charged into the hydrolysis reaction tank. For example, the pulp can be concentrated using a dehydrator such as a screw press or belt filter, and then a predetermined amount can be charged into the reaction tank. When a dry pulp sheet is used as the raw material, the pulp can be disintegrated using a crusher such as a roll crusher before being charged into the reaction tank.

[0025] In one embodiment, acid hydrolysis is carried out using an inorganic acid such as a mineral acid, and examples of suitable acids include hydrochloric acid, sulfuric acid, and nitric acid. Acid hydrolysis can be carried out, for example, using a dispersion with a pulp concentration of 3 to 10% by weight (solid content equivalent) adjusted to an acid concentration of 0.1 to 30% by weight, at a reaction temperature of 80 to 100°C for a reaction time of 30 minutes to 3 hours. The hydrolyzed pulp can be neutralized by adding an alkaline agent or the like and washed. Subsequently, in a deliquifying step, solid-liquid separation into the hydrolyzed pulp and the waste acid can be performed. Furthermore, the hydrolyzed pulp can be dried in a dryer and mechanically pulverized and classified to a specified size in a pulverizer. After neutralization, washing, and deliquifying, the solid content may be adjusted by dehydration before drying. Adjusting the solid content before drying facilitates control of the physical properties of the powdered cellulose.

[0026] As the mill used in the method for producing powdery cellulose of the present invention, for example, a cutting mill, a hammer mill, an impact mill, an airflow mill, a roller mill, etc. can be suitably used, and specific examples include the following: ■Cutting mills: Mesh Mill HA Series (manufactured by HORAI), Knife Mill (manufactured by PALMAN), Cutter Mill (manufactured by Tokyo Atomizer Manufacturing), Centri Cutter (manufactured by Nippon Coke Industrial Co., Ltd.), Rotary Cutter Mill (manufactured by Nara Machinery Works), Turbo Cutter (manufactured by Freund Turbo), etc. Hammer mills: Jaw crushers (manufactured by Makino), atomizer TAP (manufactured by Tokyo Atomizer Manufacturing), micro pulverizers (manufactured by Hosokawa Micron), fine impact mills (manufactured by Hosokawa Micron), atomizers (manufactured by Seishin Enterprises), hammer crushers (manufactured by Makino Sangyo), etc. ■Impact mills: ACM Pulverizer (Hosokawa Micron), Inomizer (Hosokawa Micron), CUM-type centrifugal mill (Nippon Coke Industrial Co., Ltd.), Exceed Mill (Makino Sangyo Co., Ltd.), Ultraplex (Makino Sangyo Co., Ltd.), Contraplex (Makino Sangyo Co., Ltd.), Coroplex (Makino Sangyo Co., Ltd.), Impeller Mill (Seishin Enterprises Co., Ltd.), Tornado Mill (Sansho Industry Co., Ltd.), Nea Mill (Dalton Co., Ltd.), HT-type fine crusher (Horai Co., Ltd.), Jiyu Crusher (Nara Machine Works, Ltd.), New Cosmomizer (Nara Machine Works, Ltd.), Turbo Mill (Freund Turbo), Super Powder Mill (Nishimura Machine Works, Ltd.), Blade Mill (Nisshin Engineering Co., Ltd.), Super Rotor (Nisshin Engineering Co., Ltd.), Wheeley Crusher (Yoshida Manufacturing Co., Ltd.), Universal Mill (Tokuju Kogyosho Co., Ltd.), etc. ■Airflow mills: Gather mill (manufactured by Polaris), CGS type jet mill (manufactured by Nippon Coke Industrial Co., Ltd.), spiral jet (manufactured by Hosokawa Micron), counter jet mill (manufactured by Hosokawa Micron), micron jet (manufactured by Hosokawa Micron), cross jet mill (manufactured by Kurimoto Iron Works), supersonic jet mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), super jet mill (manufactured by Nisshin Engineering Co., Ltd.), selenium mirror (manufactured by Masuko Sangyo), New Micro Sictomat (manufactured by Masuno Manufacturing Co., Ltd.), Kryptron (manufactured by EarthTechnica Co., Ltd.), etc. ■ Roller mills: Vertical roller mill (Seishin Enterprises), roller mill (Kotobuki Giken Kogyo), VX mill (Kurimoto Iron Works), KVM type vertical mill (Earth Technica), IS mill (IHI Plant Engineering), etc. Among these, it is preferable to use mills such as Micro Pulverizer (manufactured by Hosokawa Micron), Jiyu Pulverizer (manufactured by Nara Machinery Works), Turbo Mill (manufactured by Freund Corporation), Super Powder Mill (manufactured by Nishimura Machinery Works), Blade Mill (manufactured by Nisshin Engineering), Vertical Roller Mill (manufactured by Seishin Enterprises), Mesh Mill HA Series (manufactured by Horai), Knife Mill (manufactured by Parman), Supersonic Jet Mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and Current Jet (manufactured by Nisshin Engineering), because of their excellent fine grinding properties.

[0027] In the present invention, pulp may be pulverized in two stages. For example, powdery cellulose can be produced by a method including a first pulverization step in which pulp is pulverized to obtain a pulverized product having an average particle size of 100 μm or less, followed by a second pulverization step in which the pulverized product obtained in the first pulverization step is further pulverized to obtain a pulverized product having an average particle size of 50 μm or less.

[0028] To impart or improve functionality to the powdered cellulose of the present invention, the powdered cellulose raw material and other components can be mixed in any ratio and pulverized. The other components may be one or more, and may be organic or inorganic chemicals. Furthermore, chemical treatments can be performed on the cellulose raw material used as the raw material, as long as the degree of polymerization is not significantly impaired.

[0029] The apparent specific gravity of the powdered cellulose of the present invention is preferably 0.20 g / ml or more, more preferably 0.25 g / ml or more. The upper limit is preferably 0.60 g / ml or less, more preferably 0.55 g / ml or less, and even more preferably 0.50 g / ml or less or 0.45 g / ml or less. The apparent specific gravity of the powdered cellulose is calculated by placing 10 g of a sample into a 100 ml measuring cylinder, tapping the bottom of the cylinder until the height of the sample no longer decreases (manually for approximately 10 minutes), and reading the scale on the flattened surface.

[0030] thermoplastic resin The thermoplastic resin used in the present invention is preferably molded into granules for ease of handling, but may be in any form. Two or more types of thermoplastic resins may be used simultaneously.

[0031] Examples of thermoplastic resins include, but are not limited to, polyolefin resins, polyamide resins, and polystyrene resins, and any resin that can be plasticized and molded by heat can be used. Among these, polyethylene such as LDPE (low-density polyethylene) and polypropylene are preferred from the viewpoint of moldability.

[0032] In the present invention, a biodegradable resin may be used as the thermoplastic resin. Examples of biodegradable resins having thermoplastic properties include, but are not limited to, polylactic acid (PLA), polybutylene succinate, polyethylene succinate, polyglycol, polycaprolactone, and polyvinyl alcohol.

[0033] Furthermore, when kneading with powdered cellulose, another compatibilizing resin (compatibilizer) may be added to further enhance uniformity and adhesion. Known compatibilizing resins can be used, including, but not limited to, maleic anhydride-modified polypropylene (UMEX 1010, manufactured by Sanyo Chemical Industries) and Modic (registered trademark) P908 (manufactured by Mitsubishi Chemical). The compatibilizing resin functions to improve uniform mixing and adhesion between the powdered cellulose and the thermoplastic resin. Although a compatibilizing resin is not required, if one is used, it is preferably used in an amount of 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, of the molding resin material obtained by kneading.

[0034] In the present invention, a thermoplastic elastomer may also be added. The addition of a thermoplastic elastomer can impart appropriate viscosity to the molding resin material, making it less susceptible to breakage or cracking during molding by injection or the like, and enabling the stable production of an excellent molding resin material.

[0035] Examples of the thermoplastic elastomer used in the present invention include styrene-based thermoplastic elastomers. More specifically, examples include block copolymers such as styrene-butadiene-styrene (SBS) copolymer, styrene-isoprene-styrene (SIS) copolymer, styrene-ethylene-butylene-styrene (SEBS) copolymer and its modified products, styrene-ethylene-propylene-styrene (SEPS) copolymer, and styrene-butadiene-butylene-styrene (SBBS) copolymer. These may be used alone or in combination of two or more.

[0036] Examples of the thermoplastic elastomer used in the present invention include polyolefin elastomers, more specifically ethylene-butene copolymers, EPR (ethylene-propylene copolymers), modified ethylene-butene copolymers, EEA (ethylene-ethyl acrylate copolymers), modified EEA, modified EPR, α-olefin copolymers, modified IR (isoprene rubber), ethylene-acrylic acid modified products, ethylene-vinyl acetate copolymers, and acid-modified products thereof, and mixtures containing these as the main components. These may be used alone or in combination of two or more.

[0037] Preferred thermoplastic elastomers for use in the present invention include styrene-butadiene block copolymers, styrene-ethylene-butylene-styrene (SEBS) copolymers and modified products thereof, ethylene-octene copolymers, propylene-ethylene copolymers, etc. In the case of styrene-ethylene-butylene-styrene (SEBS) copolymers, the styrene content is preferably 10 to 20 mass%.

[0038] The molding resin material of the present invention can be subjected to a heat treatment or the like to obtain a molded article. The temperature at which the resin material is heated in the heating, melting, kneading, or other treatments is usually about 100 to 300°C, preferably about 110 to 250°C, and particularly preferably about 120 to 220°C. The molded article obtained by the heat treatment can be molded into the desired shape by a known method.

[0039] The molding resin material of the present invention can be prepared by heating and kneading powdered cellulose and a thermoplastic resin using equipment commonly used in resin molding, such as a general extruder or twin-screw kneading extruder. Examples of twin-screw kneading extruders that can be used include the Xplore Compounder (Xplore Instruments) and the TEX series (Japan Steel Works).

[0040] The molding resin material of the present invention can be used to produce various molded articles. For molding, a conventional method used for molding thermoplastic resins can be used, such as, but not limited to, injection molding, extrusion molding, blow molding, mold molding, hollow molding, and foam molding.

[0041] The molding resin material of the present invention or the molded article obtained by molding it may contain other components in addition to the thermoplastic resin and powdered cellulose. These other components may be organic or inorganic, and include, for example, alkalis such as magnesium hydroxide and calcium hydroxide; inorganic fillers such as clay, talc, calcium carbonate, mycelium, titanium dioxide, and zinc oxide; organic fillers such as carbon black, graphite, and glass flakes; dyes and pigments such as red iron oxide, azo pigments, and phthalocyanines; and property-modifying additives such as dispersants, lubricants, plasticizers, mold release agents, flame retardants, antioxidants (phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants), antistatic agents, light stabilizers, UV absorbers, metal deactivators, crystallization accelerators (nucleating agents), foaming agents, crosslinking agents, and antibacterial agents.

[0042] The molding resin material of the present invention can be molded to suit various purposes and can be used as a substitute for plastic products. Examples of molded articles obtainable from the molding resin material of the present invention include automobile parts, automobile interiors such as dashboards, airplane luggage compartments, structural components for transportation equipment, housings for home appliances, electrical appliance components, cards, various containers such as toner containers, building materials, seedling pots, agricultural sheets, writing implements, wooden products, household appliances, straws, cups, toys, sporting goods, port components, building components, generator components, tools, fishing gear, packaging materials, 3D printer models, pallets and trays, food containers, tableware, cutlery such as spoons and forks, chopsticks, and various sheets. [Example]

[0043] The present invention will be described in more detail below with reference to experimental examples of the present invention, but the present invention is not limited to these experimental examples. Unless otherwise specified, parts and % represent parts by mass and % by mass, and numerical ranges are stated as including their endpoints.

[0044] Resin material manufacturing (1) Manufacturing Example 1 Powdered cellulose (W-100GK, Nippon Paper Industries Co., Ltd.), polypropylene (J779EA, Prime Polymer Co., Ltd.), and modified rosin (tall oil rosin, softening point 73°C, Harima Chemicals Co., Ltd.) were mixed in a ratio of 25:74.5:0.5 and mixed at 200°C for 3 minutes using a twin-screw extruder (Xplore Compounder 15, Xplore Instruments Inc.) to continuously produce a molding resin material. The powdered cellulose used in this experiment was produced by pulverizing bleached sulfite pulp derived from wood, and had an average particle size (D50) of approximately 37 μm and an apparent specific gravity of approximately 0.30 g / ml. (2) Manufacturing Example 2 A molding resin material was produced in the same manner as in Production Example 1, except that a reinforced rosin (softening point 107°C, manufactured by Harima Chemicals) was used as the modified rosin. (3) Manufacturing Example 3 A molding resin material was produced in the same manner as in Production Example 1, except that rosin glycerin ester (softening point 82°C, manufactured by Harima Chemicals) was used as the modified rosin. (4) Production Example 4 A molding resin material was produced in the same manner as in Production Example 1, except that rosin glycerin ester (softening point 92°C, manufactured by Harima Chemicals) was used as the modified rosin. (5) Production Example 5 A molding resin material was produced in the same manner as in Production Example 1, except that a polyoxyethylene glycol resin acid ester (liquid at room temperature, manufactured by Harima Chemicals) produced using rosin as a raw material was used as the modified rosin. (6) Production Example 6 A molding resin material was produced in the same manner as in Production Example 1, except that the compounding ratio of powdered cellulose, polypropylene, and tall oil rosin was 25:73:2. (7) Production Example 7 (Comparative Example) A molding resin material was produced in the same manner as in Production Example 1, except that powdered cellulose and polypropylene were used in a blending ratio of 25:75 and no modified rosin was added. (8) Production Example 8 (Comparative Example) A molding resin material was produced in the same manner as in Production Example 1, except that a polypropylene-based compatibilizer (maleic anhydride-modified polypropylene, softening point 145°C, UMEX 1010, manufactured by Sanyo Chemical Industries, Ltd.) was used instead of the modified rosin.

[0045] Resin material evaluation (1) Cellulose dispersibility The strands of molding resin material extruded from the extruder were cut into lengths of several millimeters, sandwiched between two sheets of transparent heat-resistant film, and gradually heated and pressed using a press heated to 160-200°C. After pressing, the dispersion state of the powdered cellulose was visually evaluated based on the following criteria. ◎: The powdered cellulose is dispersed so uniformly that its distribution is indistinguishable. ○: The powdered cellulose is not unevenly distributed and is generally uniformly dispersed. △: Powdered cellulose is slightly aggregated, but is dispersed overall ×: Powdered cellulose aggregates in places, and unevenness is observed (2) Strength test The resin material was molded into a dumbbell shape (JIS K 7139, Type A12) using a mold, and the strength of the resin was evaluated (heat barrel temperature: approximately 200°C, mold temperature: approximately 40°C, extrusion sequence: 9 bar, 2 seconds - 11 bar, 0.5 seconds - 11 bar, 24 seconds). Tensile tests were performed according to JIS K 7161 (Plastics - Testing methods for tensile properties) (tensile speed: 1 mm / min), and Charpy impact strength was measured according to JIS K 7111-1:2012.

[0046] [Table 1]

[0047] As shown in Table 1, the molding resin materials of Production Examples 1 to 6, which contained a rosin modifier, had better dispersibility of powdered cellulose than those containing no rosin modifier. Furthermore, the molding resin material according to the present invention had improved tensile strength, breaking strain, and Charpy impact strength compared to those containing no compatibilizer. It is believed that the rosin modifier plays the role of a cellulose dispersant and compatibilizer in the present invention.

Claims

1. A molding resin material comprising powdered cellulose having an average particle size of 100 μm or less, a thermoplastic resin, and a modified rosin, The material has a powdery cellulose content of 10 to 90% by mass, and the modified rosin includes one or more of rosin glycerin ester, tall oil rosin, polyoxyethylene glycol resin acid ester, and reinforced rosin.

2. 2. The molding resin material according to claim 1, wherein the blending ratio of the powdered cellulose, the thermoplastic resin, and the modified rosin is 10-90:90-10:0.1-5.

3. 2. The molding resin material according to claim 1, wherein the powdered cellulose is derived from wood.

4. A method for producing the molding resin material according to any one of claims 1 to 3, comprising: The above method includes a step of heating and kneading powdered cellulose, a thermoplastic resin, and a modified rosin to produce a molding resin material.

5. The method according to claim 4, wherein the molding resin material is continuously produced using a twin-screw kneading extruder in the heating and kneading step.

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