Patent Publication Number: US-2023136603-A1

Title: Molding resin material and method for manufacturing the same

Description:
TECHNICAL FIELD 
     The present invention relates to molding resin materials and methods for producing the same. In particular, the present invention relates to a thermoplastic molding material using a woody biomass-derived torrefied product and a thermoplastic resin, typified by polypropylene and polylactic acid, as raw materials, and to a method for producing the same. 
     BACKGROUND ART 
     Biomass materials are attracting attention as an industrial resource. A biomass material refers to a material derived from plants and other living organisms. Biomass materials are organic and emit carbon dioxide when burned. However, the carbon contained in the biomass materials is derived from the carbon dioxide that the biomass has absorbed from the atmosphere through photosynthesis during their growth. Accordingly, it can be considered that the use of biomass materials does not increase the amount of carbon dioxide in the ambient air as a whole. This nature is called carbon neutrality. 
     Against the background of global warming and other environmental problems, it is urgent to promote resource-saving, material recycling for using waste as raw materials, and the environmental recycling cycle typically for biodegradable plastics. In Japan, the Revised Recycling Law, the Green Purchasing Law, and so on have been developed, and products according to these laws are increasingly being demanded accordingly. 
     Under such circumstances, blending biomass materials into resin molded articles, which are widely used from automobile part materials to daily necessities, will promote the implementation of the carbon neutral philosophy. For example, PTL 1 discloses a composite material containing carboxymethylated cellulose nanofibers, a polymer compound having a primary amino group, an acid-modified polyolefin, and a polyolefin. PTL 2 discloses cellulosic composites containing wood pulp and a polymeric matrix. PTL 3 discloses a method for producing resin injection molded articles containing wood flour by mixing wood flour with random polypropylene resin and using an injection molding machine. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: International Publication WO2014/087767 
         PTL 2: National Publication of International Patent Application No. 2019-512591 
         PTL 3: JP 2010-138337A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, when molding is performed by simply mixing “woody biomass” and “polypropylene” and heating and melting the mixture, there occur problems that woody biomass cannot be uniformly mixed with polypropylene because of the hydrophilicity of the woody biomass; that the resin mass is cut into small pieces at the outlet of the apparatus for injecting the mixture of woody biomass and polypropylene; that the surface of the resulting molded article is not smooth; and so on. 
     For example, PTL 1, which describes using carboxymethylated cellulose nanofibers, requires carboxymethylating cellulose and, further, adding a polymer compound having a primary amino group and an acid-modified polyolefin to improve the uniformity of dispersion into polyolefin resin. This results in increased costs. 
     Accordingly, the subject of the present invention relates to providing a woody biomass-mixed thermoplastic molding material, specifically, providing at low cost a molding material in which woody biomass and a thermoplastic resin are uniformly mixed and which is less likely to cut when molded by injection or the like. 
     Solution to Problem 
     The present inventors found that a highly moldable molding resin material can be obtained by torrefying woody biomass and then mixing the woody biomass with a thermoplastic resin, such as polypropylene or polyethylene, followed by heating and kneading, and thus accomplished the present invention. 
     The present invention provides, but is not limited to, the following: 
     [1] A molding resin material comprising 40 to 90% by mass of a pulverized product from a woody biomass-derived torrefied product having an average particle size of 100 μm or less, and further comprising a thermoplastic resin.
 
[2] The material according to [1], wherein the thermoplastic resin includes a polyolefin-based resin, a polypropylene-based resin, or a polylactic acid-based resin.
 
[3] The material according to [1] or [2], wherein the material further comprises a thermoplastic elastomer.
 
[4] The material according to [3], wherein the thermoplastic elastomer includes any one of a styrene-butadiene-based block copolymer, an ethylene-octene-based copolymer, and a propylene-ethylene-based copolymer.
 
[5] The material according to [3], wherein the thermoplastic resin includes a polypropylene-based resin.
 
[6] The material according to any one of [1] to [5], wherein the woody biomass-derived torrefied product is a product of torrefaction of woody biomass under conditions of an oxygen concentration of 10% or less at 240 to 350° C.
 
[7] A method for producing a molding resin material, the method comprising mixing 40 to 90% by mass of a pulverized product from a woody biomass-derived torrefied product having an average particle size of 100 μm or less and a thermoplastic resin.
 
     Advantageous Effects of Invention 
     The present invention enables consistent production of a molding resin material containing a woody biomass-derived torrefied product. Also, by increasing the proportion of the woody biomass-derived torrefied product, a molding resin material superior in terms of carbon neutrality can be produced. 
    
    
     DESCRIPTION OF EMBODIMENTS 
     The torrefied product used in the present invention is obtained by torrefying ground woody biomass with a size of, for example, 50 mm or less under conditions of an oxygen concentration of 10% or less and a material temperature of 240° C. to 350° C. 
     The present invention uses such a woody biomass-derived torrefied product. Wood used as a source of woody biomass can be any of hardwoods or softwoods. Specific examples of hardwoods include  Eucalyptus , Para rubber tree, Japanese Beech, Japanese Lime, White Birch, poplar,  acacia , oak,  Acer mono, Kalopanax, Ulmus , Empress tree, Japanese Bigleaf  Magnolia , Willow,  Kalopanax, Quercus phillyraeoides, Quercus serrata , Sawtooth Oak,  Aesculus turbinata , Japanese  zelkova , Japanese Cherry Birch, giant dogwood, and  Fraxinus lanuginose . Specific examples of softwoods include Japanese Cedar, Yezo Spruce, Japanese Larch, Japanese Black Pine, Sakhalin Fir, Japanese White Pine, Japanese Yew, Japanese Thuja, tigertail spruce,  Picea  bicolor, Yew plum pine, Japanese Fir, Sawara cypress, Japanese Douglas Fir, False arborvitae, Hiba, Southern Japanese Hemlock, Northern Japanese Hemlock, Japanese cypress, Japanese yew, Japanese plum-yew, spruce, Yellow Cedar (Alaska Cedar), Lawson&#39;s cypress (Port-Orford Cedar), Douglas Fir (Oregon Pine), Sitka Spruce,  Radiata  Pine, Eastern Spruce, Eastern White Pine, Western Larch, Western Fir, Western Hemlock, and Tamarack. The wood to be used is however not limited to those. 
     Among those,  Eucalyptus  wood and Para rubber tree ( Hevea brasiliensis ) are preferable. Examples of  Eucalyptus  include  Eucalyptus  (hereinafter abbreviated as  E .)  calophylla, E. citriodora, E. diversicolor, E. globulus, E. grandis, E. urograndis, E. gummifera, E. marginata, E. nesophila, E. nitens, E. amygdalina, E. camaldulensis, E. delegatensis, E. gigantea, E. muelleriana, E. obliqua, E. regnans, E. sieberiana, E. viminalis , and  E. marginata.    
     In the present invention, the woody biomass used as the raw material may be in any form, and preferred examples include, but are not limited to, wood chips, bark, wood powder, and sawdust. In a preferred embodiment, woody biomass of 50 mm or less in size can be used as the raw material. For example, woody biomass may be ground to a size of 50 mm or less. Preferably, woody biomass ground to a size of 1 mm or more and 50 mm or less is used as the raw material. In the present invention, the size of ground woody biomass is that defined by the size of circular openings of a sifter. For grinding, the woody biomass is ground preferably with, for example, a hammer mill or a knife-cutting type chipper for biomass fuels. 
     In the present invention, a woody biomass-derived torrefied product is used. In general, torrefaction refers to a heating treatment performed at lower temperatures than the temperature for what is called carbonizing treatment in a low oxygen atmosphere. Wood is generally subjected to carbonizing treatment at 400° C. to 700° C. but is, in the present invention, torrefied at 240° C. to 350° C. Torrefaction provides a solid fuel having a higher energy density than that of the starting material thereof. 
     In the present invention, torrefaction is performed under treatment conditions of an oxygen concentration of 10% or less and a material temperature of 240° C. to 350° C. The material temperature in the torrefaction is the temperature of the woody biomass at and around the outlet of the apparatus for torrefying treatment. In the present invention, torrefaction is performed under the condition of an oxygen concentration of 10% or less. An oxygen concentration exceeding 10% can reduce material yield and calorific yield. The torrefied product is difficult to pulverize to smaller particle sizes at a material temperature of less than 240° C. Also, if the material temperature increases to more than 350° C., the material yield and the calorific yield decrease. The material temperature is preferably 240° C. to 330° C., more preferably 250° C. to 320° C. Pyrolysis of hemicellulose becomes marked at and around 270° C., whereas cellulose and lignin are markedly pyrolyzed at and around 355° C. and 365° C., respectively. Accordingly, it can be expected that a molding resin material capable of providing both satisfactory material yield and pulverizability will be produced by controlling the torrefaction temperature at 170° C. to 350° C. to allow the preferential pyrolysis of hemicellulose. 
     In the present invention, the apparatus for torrefying treatment is preferably, but not particularly limited to, a rotary kiln and/or a vertical furnace. Preferably, the inside of the apparatus is purged with an inert gas, such as nitrogen, to adjust the oxygen concentration to 10% or less. Preferably, the torrefying treatment period is, for example, but not particularly limited to, 1 to 180 minutes, more preferably 5 to 120 minutes, still more preferably 10 to 60 minutes. When a continuous apparatus is used, the residence time in the torrefying apparatus can be controlled. 
     In the present invention, an external heat-type torrefying apparatus may be used as the apparatus for torrefying treatment. For example, an external combustion rotary kiln is an apparatus having a structure in which the kiln outer cylinder partially or entirely covers the kiln inner cylinder. Woody biomass is torrefied in the inner cylinder, and the fuel is burned in the outer cylinder to indirectly heat the woody biomass within the inner cylinder. The temperature within the kiln outer cylinder may be set to 400° C. to 800° C. and is preferably 450° C. to 750° C. A temperature within the kiln outer cylinder of less than 400° C. leads to insufficient pyrolysis of woody biomass within the kiln inner cylinder, reducing the pulverizability of the resulting solid fuel. In contrast, a temperature of more than 800° C. excessively increases the temperature of the woody biomass within the kiln inner cylinder, reducing the material yield and calorific yield of the resulting solid fuel. 
     The torrefied product used in the present invention preferably provides a material yield of 60% to 90% and a calorific yield of 70% to 95% with respect to the raw material woody biomass. The hardgrove grindability index (HGI), which is an index of the pulverizability and is specified in JIS M 8801: 2004, is preferably 25 or more, more preferably 30 or more. The higher the HGI, the easier to pulverize the material. When the HGI is in the range of 25 to 70, the torrefied product is easy to mix with a thermoplastic resin for molding treatment. 
     The torrefied product of the present invention used in the present invention may be formed into a shape. More specifically, the starting material (torrefied product) in a woody biomass-ground state is compacted into briquettes or pellets. Forming into such compacts facilitates handling and increases density, reducing transportation costs. Preferably, the bulk density of the compacts after compaction is 500 kg/m 3  or more, more preferably 600 kg/m 3  or more. The bulk density can be measured in accordance with JIS K 2151, 6. “Test Method for Bulk Density”. 
     In the present invention, the apparatus for forming the torrefied product into compacts is not particularly limited but is desirably, for example, a briquetter (manufactured by Kitagawa Corporation), a ring die pelletizer (manufactured by CPM), a flat die pelletizer (manufactured by Kahl or Dalton Corporation), or the like. 
     When the torrefied product is formed into compacts in the present invention, the moisture content of the torrefied product is preferably 8% to 50%, more preferably 10% to 30%. The torrefied product with a moisture content of less than 8% clogs the inside of the briquetter or pelletizer, failing to form compacts consistently. The torrefied product with a moisture content of more than 50% is difficult to form into compacts and is discharged in the form of powder or paste. 
     In the present invention, a binder may be added into the torrefied product. Suitable examples of the binder include, but are not particularly limited to, organic polymers such as starch and lignin, inorganic polymers such as acrylamide, and agricultural residues such as bran (residue from wheat flour production). From the viewpoint of aiming at efficient and effective use of woody biomass, the proportion of the binder added is desirably smaller and is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, relative to 100 parts by mass of the torrefied product. However, even if 50 parts by mass or more of binder is added, compaction is not necessarily impossible. 
     In the present invention, the torrefied product is preferably pulverized before kneading with a thermoplastic resin. The average particle size of the pulverized product is required to be set to 100 μm or less, and is further preferably 50 μm or less. The pulverized product from the torrefied product, having an average particle size of more than 100 μm is difficult to uniformly mix with the resin and can cause problems that the resin mass is cut into small pieces at the outlet of the apparatus for injecting the mixture of the pulverized product and the resin, that transportation to the cooling device is difficult, and so on. The average particle size refers to the 50% volume average particle size (D50) determined by a laser light scattering method (laser diffraction method) and can be measured with a laser diffraction/scattering particle size analyzer (apparatus name: Mastersizer 2000, manufactured by Malvern) or the like. 
     The pulverizer used for pulverizing the torrefied product can be an apparatus capable of pulverizing organic matter, and examples include, but are not limited to, ball mills, rod mills, bead mills, conical mills, disk mills, edge mills, hammer mills, mortars, pellet mills, VSI mills, wheel mills, roller mills, Jet mills, and mass colloiders. 
     The molding resin material of the present invention can be obtained by heating and kneading the above-described torrefied product with a thermoplastic resin. A higher proportion of the torrefied product in the molding resin material is preferable to achieve a high level of carbon neutrality. In view of the resin material to be obtained and the manufacture and strength of molded articles, the proportion of the torrefied product is preferably 10% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less. 
     The thermoplastic resin used in the present invention is preferably formed into particles in view of handling but may be in any form. Two or more thermoplastic resins may be used at one time. The thermoplastic resins include biodegradable thermoplastic resins. From the viewpoint of enhancing the uniformity and adhesion in kneading with the torrefied product, a compatibilizing resin (compatibilizer) that is a thermoplastic resin may be added. 
     Examples of the thermoplastic resin include, but are not limited to, polyethylene and polypropylene. Any other resin that can be plasticized by heat may be used. Polyethylene, such as LDPE (low-density polyethylene), and polypropylene are particularly preferable in view of moldability. 
     In the present invention, a biodegradable resin may be used as the thermoplastic resin. Examples of the biodegradable thermoplastic resin include, but are not limited to, polylactic acid (PLA), polybutylene succinate, polyethylene succinate, polyglycol, polycaprolactone, and polyvinyl alcohol. 
     Known compatibilizer may be used as the compatibilizing resin, and examples include, but are not limited to, maleic acid-modified polypropylene (UMEX 1010, produced by Sanyo Chemical Industries) and Modic (registered trademark) P908 (produced by Mitsubishi Chemical Corporation). The compatibilizing rein functions to increase the mixing uniformity and adhesion of the torrefied product with the thermoplastic resin. The compatibilizing resin is not necessarily used. If used, the amount to be used is such that up to about 15% by mass is contained in the molding resin material obtained by kneading. 
     In the present invention, the addition of a thermoplastic elastomer enables to stably produce a molding resin material with a high viscosity in which cutting, cracking, and the like are not caused during injection molding, even when the pulverized product from a woody biomass-derived torrefied product is blended. 
     Examples of the thermoplastic elastomer used in the present invention include styrene-based thermoplastic elastomers. More specifically, examples thereof include block copolymers such as styrene-butadiene-styrene (SBS) copolymers, styrene-isoprene-styrene (SIS) copolymers, styrene-ethylene-butylene-styrene (SEBS) copolymers, styrene-ethylene-propylene-styrene (SEPS) copolymers, and styrene-butadiene-butylene-styrene (SBBS) copolymers. These may be used alone or in combination of two or more. 
     Also, examples of the thermoplastic elastomer used in the present invention include polyolefin-based elastomers. More specifically, examples thereof include ethylene-butene copolymers, EPRs (ethylene-propylene copolymers), modified ethylene-butene copolymers, EEAs (ethylene-ethyl acrylate copolymers), modified EEAs, modified EPRs, modified EPDMs (ethylene-propylene-diene ternary copolymers), ionomers, α-olefin copolymers, modified IRs (isoprene rubbers), modified SEBSs (styrene-ethylene-butylene-styrene copolymers), halogenated isobutylene-paramethyl styrene copolymers, ethylene-acrylic acid modified products, ethylene-vinyl acetate copolymers, and acid-modified products thereof, and mixtures containing any of them as the main component. These may be used alone or in combination of two or more. 
     Examples of the preferred thermoplastic elastomer used in the present invention include a styrene-butadiene-based block copolymer, an ethylene-octene-based copolymer, and a propylene-ethylene-based copolymer. These may be modified with maleic anhydride, fumaric acid anhydride, or the like. In the styrene-butadiene-based block copolymer, the content of styrene is preferably 15 to 30% by mass. 
     The proportion of the thermoplastic elastomer is preferably 1 to 20% by mass, and more preferably 3 to 10% by mass. That is, the pulverized product from the woody biomass-derived torrefied product, the thermoplastic resin, and the thermoplastic elastomer is preferably blended in a ratio of 40 to 90:59 to 10:1 to 20. 
     The molding resin material of the present invention can form molded products by heat treatment. The temperature for the heat treatment (treatment for heating, melting, kneading, and so on) of the molding resin material of the present invention is normally about 100° C. to 300° C., preferably about 110° C. to 250°, and particularly preferably about 120° C. to 220° C. The molded product obtained by the heat treatment may be formed into a desired shape by known resin molded products. 
     In the method for producing the molding resin material of the present invention, an apparatus generally used for resin molding may be used for heating and kneading the torrefied product and a thermoplastic resin. For example, a conventional extruder may be used. 
     A variety of molded articles can be produced using the molding resin material of the present invention. Common methods used for molding a thermoplastic resin can be applied to the molding. Examples of such methods include, but are not limited to, injection molding, extrusion, blow molding, die molding, hollow molding, and foam molding. 
     The molding resin material of the present invention or the molded articles obtained by molding the molding resin material may contain organic matter and/or inorganic matter other than the thermoplastic resin and the torrefied product. Such other constituents include, for example, alkalis, such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide; inorganic fillers, such as clay, talc, calcium carbonate, mica, titanium dioxide, and zinc oxide; organic fillers, such as carbon black, graphite, and glass flakes; dyes or pigments, such as colcothar, azo pigments, and phthalocyanine; and modification additives, such as dispersants, lubricants, plasticizers, release agents, flame retardants, antioxidants (phenol-based antioxidants, phosphorus antioxidants, sulfur-based antioxidants), antistatic agents, light stabilizers, ultraviolet absorbent, metal inactivators, crystallization accelerators (nucleating agents), foaming agents, crosslinking agents, and antibacterial agents. 
     The molding resin material of the present invention may be molded according to various purposes, and are available as substitutes for plastic products. The molded article that can be obtained from the molding resin material of the present invention can be widely applied to, for example, trays or the like, automobile parts, automobile dashboards and other interiors, airplane luggage compartments, structural members of transportation equipment, enclosures (housings) of household appliances, electrical appliance components, cards, toner containers and various other containers, construction materials, seedling pots, agricultural sheets, writing instruments, wooden products, household utensils, straws, cups, toys, sporting goods, harbor components, construction components, power generator components, tools, fishing equipment, packaging materials, 3D printer-modeling products, pallets, foods containers, dishes, cutlery (e.g., spoon, fork), chopsticks, various sheets. These products will be disposed of when no longer needed. However, even though, for example, they are incinerated and emit carbon dioxide, the carbon dioxide derived from the woody biomass-derived torrefied product can be considered to be a portion that does not increase the amount of carbon dioxide in the ambient air. 
     EXAMPLES 
     Although the present invention will be further described in detail with reference to Experimental Examples of the present invention, the present invention is not limited to the Experimental Examples. Note that “part(s)” and “%” represent part(s) by mass and % by mass, respectively, unless otherwise specified, and that the range of values includes the endpoints of the range. 
     Experiment 1 
     (1) Production of Molding Resin 
     Sample 1-1 
       Eucalyptus urograndis  wood chips were subjected to grinding treatment with a disc chipper. After grinding, the chip-ground material of 1 mm to 50 mm in size was dried using a conveyor dryer (manufactured by Alvan Blanch) at a hot air temperature of 70° C. for 3 hours to adjust the moisture content to 10%. 
     The chip-ground material was then torrefied at an oxygen concentration of 1% or less and a residence time of 12 minutes in a large rotary kiln-type carbonizing furnace with the material temperature of the chip-ground material in the carbonizing furnace controlled to 260° C., thus obtaining a woody biomass-derived torrefied product. After being cooled, the resulting torrefied product was crushed with a Lab Mill (manufactured by OSAKA CHEMICAL Co., Ltd.) until having an average particle size of 50 μm. 
     Then, the pulverized product from the torrefied product and a polypropylene (trade name: J106G, produced by Prime Polymer, melt flow rate: 15 g/10 min) were mixed in a ratio of 50:50, and heated and kneaded in a Labo Plastomill (R100, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at 175° C. and 45 rpm for 5 minutes to produce a molding resin material (weight ratio of pulverized product from torrefied product to polypropylene=50:50). 
     The average particle size of the pulverized product from the torrefied product was measured with a laser diffraction particle size measurement apparatus (Mastersizer 3000, manufactured by Malvern Panalytical Ltd.), and the 50% particle size on a volume basis was taken as the average particle size. 
     Sample 1-2 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polypropylene were mixed in a ratio of 60:40 (weight ratio of pulverized product from torrefied product to polypropylene=60:40). 
     Sample 1-3 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polypropylene were mixed in a ratio of 70:30 (weight ratio of pulverized product from torrefied product to polypropylene=70:30). 
     Sample 1-4 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polypropylene were mixed in a ratio of 80:20 (weight ratio of pulverized product from torrefied product to polypropylene=80:20). 
     Sample 1-5 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and a polyethylene (trade name: Novatec HD HJ490, produced by Japan Polyethylene Corporation, melt flow rate: 20 g/10 min) were mixed in a ratio of 50:50 (weight ratio of pulverized product from torrefied product to polyethylene=50:50). 
     Sample 1-6 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polyethylene were mixed in a ratio of 60:40 (weight ratio of pulverized product from torrefied product to polyethylene=60:40). 
     Sample 1-7 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polyethylene were mixed in a ratio of 70:30 (weight ratio of pulverized product from torrefied product to polyethylene=70:30). 
     Sample 1-8 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polyethylene were mixed in a ratio of 80:20 (weight ratio of pulverized product from torrefied product to polyethylene=80:20). 
     Sample 1-9 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and a polylactic acid (trade name: Ingeo Biopolymer 3001D, produced by NatureWorks LLC, melt flow rate: 22 g/10 min) were mixed in a ratio of 50:50 (weight ratio of pulverized product from torrefied product to polylactic acid=50:50). 
     Sample 1-10 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polylactic acid were mixed in a ratio of 60:40 (weight ratio of pulverized product from torrefied product to polylactic acid=60:40). 
     Sample 1-11 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polylactic acid were mixed in a ratio of 70:30 (weight ratio of pulverized product from torrefied product to polylactic acid=70:30). 
     Sample 1-12 
     A molding resin material was produced in the same manner as Sample 1-1, except that the pulverized product from the torrefied product and the polylactic acid were mixed in a ratio of 80:20 (weight ratio of pulverized product from torrefied product to polylactic acid=80:20). 
     Sample 1-13, Comparative Example 
     A molding resin material was produced in the same manner as Sample 1-1, except that a cellulose powder (trade name: KC FLOCK W-50, produced by NIPPON PAPER INDUSTRIES CO., LTD.)) and a polypropylene (J106G, produced by Prime Polymer, melt flow rate: 15 g/10 min) were mixed in a ratio of 30:70 (weight ratio of cellulose powder to polypropylene=30:70). 
     Sample 1-14, Comparative Example 
     A molding resin material was produced in the same manner as Sample 1-1, except that the cellulose powder and the polypropylene were mixed in a ratio of 50:50 (weight ratio of cellulose powder to polypropylene=50:50). 
     Sample 1-15, Comparative Example 
     A molding resin material was produced in the same manner as Sample 1-1, except that a fluff pulp (trade name: Eucafluff, manufactured by Suzano) and the polypropylene were mixed in a ratio of 10:90 (weight ratio of fluff pulp to polypropylene=30:70). 
     Sample 1-16, Comparative Example 
     A molding resin material was produced in the same manner as Sample 1-1, except that the fluff pulp and the polypropylene were mixed in a ratio of 20:80 (weight ratio of fluff pulp to polypropylene=20:80). 
     (2) Evaluation of Molding Resin 
     For the above molding resins, the kneadability was evaluated using a Labo Plastomill (R100, manufactured by Toyo Seiki Seisaku-sho, Ltd.). 
     Excellent: the flowability of the kneaded product was very good (uniformly kneaded, good flowability) 
     Good: the flowability of the kneaded product was good (uniformly kneaded, the molded product was likely to be cut) 
     Fair: the flowability of the kneaded product was poor (ununiformly kneaded) 
     Poor: not kneadable 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Biomass 
                 Resin 
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Torrefied product 
                 Cellulose 
                 Fluff  
                   
                   
                 Polylactic  
                 Labo  
               
               
                   
                 pulverized product 
                 powder 
                 pulp 
                 Polypropylene 
                 Polyethylene 
                 acid 
                 Plastomill 
               
               
                 Sample 
                 (%) 
                 (%) 
                 (%) 
                 (%) 
                 (%) 
                 (%) 
                 kneadability 
               
               
                   
               
               
                 1-1 
                 50 
                   
                   
                 50 
                   
                   
                 Excellent 
               
               
                 1-2 
                 60 
                   
                   
                 40 
                   
                   
                 Excellent 
               
               
                 1-3 
                 70 
                   
                   
                 30 
                   
                   
                 Good 
               
               
                 1-4 
                 80 
                   
                   
                 20 
                   
                   
                 Good 
               
               
                 1-5 
                 50 
                   
                   
                   
                 50 
                   
                 Excellent 
               
               
                 1-6 
                 60 
                   
                   
                   
                 40 
                   
                 Excellent 
               
               
                 1-7 
                 70 
                   
                   
                   
                 30 
                   
                 Good 
               
               
                 1-8 
                 80 
                   
                   
                   
                 20 
                   
                 Good 
               
               
                 1-9 
                 50 
                   
                   
                   
                   
                 50 
                 Excellent 
               
               
                 1-10 
                 60 
                   
                   
                   
                   
                 40 
                 Excellent 
               
               
                 1-11 
                 70 
                   
                   
                   
                   
                 30 
                 Good 
               
               
                 1-12 
                 80 
                   
                   
                   
                   
                 20 
                 Good 
               
               
                 1-13 
                   
                 30 
                   
                 70 
                   
                   
                 Fair 
               
               
                 (Comparative 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Example) 
                   
                   
                   
                   
                   
                   
                   
               
               
                 1-14 
                   
                 50 
                   
                 50 
                   
                   
                 Poor 
               
               
                 (Comparative 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Example) 
                   
                   
                   
                   
                   
                   
                   
               
               
                 1-15 
                   
                   
                 10 
                 90 
                   
                   
                 Fair 
               
               
                 (Comparative 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Example) 
                   
                   
                   
                   
                   
                   
                   
               
               
                 1-16 
                   
                   
                 20 
                 80 
                   
                   
                 Poor 
               
               
                 (Comparative 
                   
                   
                   
                   
                   
                   
                   
               
               
                 Example) 
               
               
                   
               
            
           
         
       
     
     As presented in Table 1, the molding resin material of the present invention had better kneadability than the molding resin materials produced by adding cellulose powder or fluff pulp. The present invention enables the production of a molding resin material that is superior in flowability and allows injection molding. 
     Experiment 2 
     (1) Production of Molding Resin 
     Sample 2-1 
       Eucalyptus urograndis  wood chips were subjected to grinding treatment with a disc chipper. After grinding, the chip-ground material of 1 mm to 50 mm in size was dried using a conveyor dryer (manufactured by Alvan Blanch) at a hot air temperature of 70° C. for 3 hours to adjust the moisture content to 10%. 
     The chip-ground material was then torrefied at an oxygen concentration of 1% or less and a residence time of 12 minutes in a large rotary kiln-type carbonizing furnace with the material temperature of the chip-ground material in the carbonizing furnace controlled to 260° C., thus obtaining a woody biomass-derived torrefied product. After being cooled, the resulting torrefied product was crushed with a Lab Mill (manufactured by OSAKA CHEMICAL Co., Ltd.) until having an average particle size of 50 μm. 
     Then, the pulverized product from the torrefied product, a polypropylene (trade name: J107G, produced by Prime Polymer, melt flow rate: 30 g/10 min), and a styrene-butadiene block copolymer (product name: H1052, content of styrene: 23%, produced by Asahi Kasei Corporation) as the thermoplastic elastomer were mixed in a ratio of 50:40:10, and heated and kneaded in a Labo Plastomill (R100, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at 175° C. and 45 rpm for 5 minutes to produce a molding resin material. 
     The average particle size of the pulverized product from the torrefied product was measured with a laser diffraction particle size measurement apparatus (Mastersizer 3000, manufactured by Malvern Panalytical Ltd.), and the 50% particle size on a volume basis was taken as the average particle size. 
     Sample 2-2 
     A molding resin material was produced in the same manner as Sample 2-1, except that a styrene-butadiene block copolymer (product name: H1062, content of styrene: 21%, produced by Asahi Kasei Corporation) was used as the thermoplastic elastomer. 
     Sample 2-3 
     A molding resin material was produced in the same manner as Sample 2-1, except that a styrene-butadiene block copolymer (product name: H1221, content of styrene: 18%, produced by Asahi Kasei Corporation) was used as the thermoplastic elastomer. 
     Sample 2-4 
     A molding resin material was produced in the same manner as Sample 2-1, except that a propylene-ethylene copolymer (product name: V4301, produced by Dow Chemical) was used as the thermoplastic elastomer. 
     Sample 2-5 
     A molding resin material was produced in the same manner as Sample 2-1, except that the pulverized product from the torrefied product, a polypropylene (trade name: J107G, produced by Prime Polymer, melt flow rate: 30 g/10 min), and a styrene-butadiene block copolymer (product name: H1052, content of styrene: 23%, produced by Asahi Kasei Corporation) as the thermoplastic elastomer, and a compatibilizer (product name: UMEX 1010, produced by Sanyo Chemical Industries, Ltd.) were mixed in a ratio of 50:39.5:10:0.5. 
     Sample 2-6 
     A molding resin material was produced in the same manner as Sample 2-1, except that the pulverized product from the torrefied product and the polypropylene were mixed in a ratio of 50:50 without adding the thermoplastic elastomer. 
     (2) Evaluation of Molding Resin 
     For the resulting molding resin materials, the tensile strength was measured. That is, a dumb-bell according to JIS6251 was fabricated using a DSM Xplore Compounder 15 (manufactured by RheoLab Ltd.), which was measured in accordance with JIS K 7161: plastics-determination of tensile properties at a tensile rate of 1 mm/min. 
     
       
         
           
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                 Tensile strength 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Maximum 
                 Breaking 
                 Tensile 
               
               
                   
                 Thermoplastic 
                 stress 
                 strain 
                 modulus 
               
               
                 Sample 
                 elastomer 
                 (MPa) 
                 (%) 
                 (GPa) 
               
               
                   
               
               
                 2-1 
                 H1052 
                 25.1 
                 4.46 
                 2.11 
               
               
                 2-2 
                 H1062 
                 23.7 
                 4.21 
                 1.82 
               
               
                 2-3 
                 H1221 
                 23.7 
                 4.54 
                 1.29 
               
               
                 2-4 
                 V4301 
                 25.8 
                 2.63 
                 1.68 
               
               
                 2-5 
                 H1052 
                 25.7 
                 7.50 
                 0.97 
               
               
                 2-6 
                 — 
                 26.3 
                 1.80 
                 3.04 
               
               
                   
               
            
           
         
       
     
     As presented in the above Table, the molding resin materials produced by adding a thermoplastic elastomer had a higher breaking strain and a higher viscosity than the molding resin material produced without adding the thermoplastic elastomer, so that they were found to be superior in moldability.