Molding resin materials
By blending pulverized woody biomass with polyamide resin and thermoplastic elastomers, the issues of uniform mixing and cracking in molded products are resolved, achieving a cost-effective, carbon-neutral resin material with improved moldability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NIPPON PAPER IND CO LTD
- Filing Date
- 2026-02-12
- Publication Date
- 2026-05-13
AI Technical Summary
The challenge of uniformly mixing woody biomass with polyamide resin, leading to issues like cracking and non-smooth surfaces in molded products, and the high costs associated with adding surface modifiers or elastomers in existing resin compositions.
A molding resin material is created by mixing pulverized woody biomass roasted or charred material with a polyamide resin, incorporating thermoplastic elastomers, and heating and kneading the mixture under specific conditions to achieve uniform mixing and improved moldability.
The solution results in a stable, high-viscosity resin material that does not crack during injection molding, with enhanced carbon neutrality and reduced costs, while maintaining mechanical properties.
Smart Images
Figure 2026077748000001
Abstract
Description
Technical Field
[0001] The present invention relates to a molding resin material containing a woody biomass roasted product or a woody biomass carbide and a polyamide resin.
Background Art
[0002] Biomass materials as industrial resources have attracted attention. Biomass materials mean materials derived from organisms such as plants. Since biomass materials are organic substances, carbon dioxide is emitted when burned. However, since the carbon contained in this is derived from the carbon dioxide absorbed from the atmosphere by photosynthesis during the growth process of the biomass, it is considered that using biomass materials does not increase the amount of carbon dioxide in the atmosphere as a whole. This property is called carbon neutral.
[0003] In the context of global environmental problems such as global warming, resource conservation, material recycling aiming at raw materials for waste, and the promotion of environmental circulation cycles represented by biodegradable plastics have become urgent tasks. In Japan, the revised Recycling Law, the Green Purchasing Law, etc. have been established, and the needs for products corresponding to these have also increased.
[0004] In such a situation, blending biomass materials into resin molded products widely used from automotive parts to daily necessities promotes the practice of the concept of carbon neutrality. For example, Patent Document 1 describes a polyamide resin composition containing a surface modifier such as cellulose, a polyamide resin, and an oligomer of a thermoplastic resin. Patent Document 2 describes a resin composition containing cellulose, a polyamide resin, and an elastomer.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
[0006] However, when simply mixing "woody biomass" and "polyamide resin" and heating and melting them to form a molded product, there were several problems: the woody biomass is hydrophilic, making it difficult to uniformly mix with the polyamide resin; the resin mixture breaks into small pieces at the outlet of the injection molding device; and the surface of the resulting molded product is not smooth.
[0007] For example, Patent Document 1 requires the addition of surface modifiers such as oligomers of thermoplastic resins, which increases costs. Patent Document 2 requires the addition of elastomers, which similarly increases costs.
[0008] Therefore, the object of the present invention is to provide a low-cost molding resin material in which woody biomass and polyamide resin are uniformly mixed, resulting in less cutting and cracking during molding, such as during injection molding. [Means for solving the problem]
[0009] The inventors of the present invention have discovered that a molding resin material with excellent moldability can be obtained by mixing pulverized woody biomass roasted material or woody biomass charred material with a polyamide resin and then heating and kneading the mixture, thereby completing the present invention.
[0010] The present invention is not limited to the following, but includes the following: (1) A molding resin material containing 10 to 90% by mass of pulverized woody biomass roasted or woody biomass charred material having an average particle size of 100 μm or less, and further containing a polyamide resin. (2) The molding resin material according to (1), comprising any of the following as a thermoplastic elastomer: a styrene-butadiene block copolymer, an ethylene-octene copolymer, or a propylene-ethylene copolymer. (3) A molding resin material according to any one of (1) to (2), further comprising a biodegradable resin. [Effects of the Invention]
[0011] According to the present invention, it is possible to stably produce a highly viscous molding resin material containing woody biomass roasted material or woody biomass charred material that does not cut or crack during injection molding. Furthermore, by increasing the proportion of woody biomass roasted material, a molding resin material with excellent carbon neutrality can be obtained. [Modes for carrying out the invention]
[0012] The woody biomass roasted product of the present invention is obtained by heating woody biomass under conditions of an oxygen concentration of 10% or less and a material temperature of 240 to 350°C.
[0013] The woody biomass char of the present invention is obtained by heating woody biomass under conditions of an oxygen concentration of 10% or less and a material temperature of 400 to 700°C.
[0014] In the present invention, both hardwoods and conifers can be used as the woody biomass raw material. Specifically, although not limited to these, examples of hardwoods include eucalyptus, rubber tree, beech, linden, birch, poplar, acacia, oak, Japanese maple, Japanese ash, elm, paulownia, magnolia, willow, Japanese ash, evergreen oak, sawtooth oak, horse chestnut, zelkova, Japanese bush, dogwood, Japanese ash, etc. Examples of conifers include Japanese cedar, Yezo spruce, larch, Japanese black pine, Sakhalin fir, Japanese white pine, Japanese yew, Japanese cedar, fir, etc. Examples include Japanese fir, Japanese yew, fir, sawara cypress, Japanese toga cypress, Japanese cypress, Japanese cedar, Japanese hemlock, Japanese cypress, Japanese yew, Japanese yew, spruce, yellow cedar (Western cypress), Lowson cypress (Western cypress), Douglas fir (Western pine), Sitka spruce (Western spruce), Radiata pine, Eastern spruce, Eastern white pine, Western larch, Western fir, Western hemlock, and tamalac.
[0015] Among these, wood from the genus Eucalyptus and the Para rubber tree (Hevea brasiliensis) are preferred. Examples of Eucalyptus species include Eucalyptus calophylla (hereinafter abbreviated as E.), 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.
[0016] In the present invention, the form of the woody biomass used as raw material is not limited, and for example, wood chips, bark, sawdust, and sawdust can be suitably used. In a preferred embodiment, woody biomass with a size of 50 mm or less can be used as raw material. For example, the size can be adjusted to 50 mm or less by crushing the woody biomass, and it is preferable to use woody biomass that has been crushed to a size of 1 mm to 50 mm as raw material. In the present invention, the size of the woody biomass crushed material is determined by the size of the circular holes in the sieving device. When crushing woody biomass, it is preferable to crush it using, for example, a hammer mill or a knife-cutting type biomass fuel chipper.
[0017] In this invention, woody biomass roasted material is used. Generally, torrefaction is a process of heating in a low-oxygen atmosphere at a lower temperature than so-called carbonization. The temperature for normal wood carbonization is 400-700°C, but in this invention, torrefaction is performed at 240-350°C. By torrefaction, a solid fuel with a higher energy density than the starting material is obtained.
[0018] The roasting conditions in this invention are an oxygen concentration of 10% or less and a material temperature of 240 to 350°C. Here, the material temperature in roasting is the temperature of the woody biomass near the outlet of the roasting apparatus. In this invention, roasting is performed under conditions of an oxygen concentration of 10% or less, but if the oxygen concentration exceeds 10%, the material yield and heat yield may decrease. Also, if the material temperature is below 240°C, it is difficult to pulverize the roasted material to small particle sizes, and if it exceeds 350°C, the material yield and heat yield decrease. The material temperature is preferably 240 to 330°C, and even more preferably 250 to 320°C. Hemicellulose undergoes significant thermal decomposition at around 270°C, while cellulose undergoes significant thermal decomposition at around 355°C and lignin at around 365°C. Therefore, by setting the roasting treatment temperature to 170 to 350°C, it is presumed that it is possible to preferentially thermally decompose hemicellulose and produce a molding resin material that can achieve both material yield and pulverability.
[0019] In the present invention, the apparatus for performing the roasting treatment is not particularly limited, but a rotary kiln and / or a shaft furnace are preferable. In addition, it is preferable to replace the inside of the apparatus with an inert gas such as nitrogen in order to adjust the oxygen concentration to 10% or less. The treatment time of the roasting treatment is not particularly limited, but for example, 1 to 180 minutes is preferable, 5 to 120 minutes is more preferable, and 10 to 60 minutes is even more preferable. When using a continuous apparatus, the residence time in the roasting apparatus may be managed.
[0020] In the present invention, as the apparatus for performing the roasting treatment, an externally heated roasting apparatus may be used. For example, an externally heated rotary kiln has a structure in which a part or all of the inner cylinder of the kiln is covered with the outer cylinder of the kiln, performs roasting of the woody biomass inside the inner cylinder, and burns fuel inside the outer cylinder to indirectly heat the woody biomass inside the inner cylinder. The temperature inside the outer cylinder of the kiln can be 400 to 800°C, and preferably 450 to 750°C. If the temperature inside the outer cylinder of the kiln is less than 400°C, the thermal decomposition of the woody biomass inside the inner cylinder of the kiln becomes insufficient, and the pulverizability of the obtained solid fuel decreases. On the other hand, if it exceeds 800°C, the temperature of the woody biomass inside the inner cylinder of the kiln rises excessively, and the material yield and heat yield of the obtained solid fuel decrease.
[0021] The roasted product used in the present invention preferably has a material yield of 60 to 90% and a heat yield of 70 to 95% with respect to the raw material woody biomass. In addition, the Hardgrove grindability index (HGI) defined in JIS M 8801:2004, which is an index of grindability, is preferably 25 or more, and more preferably 30 or more. The higher the HGI, the easier it is to be pulverized. If the HGI is in the range of 25 to 70, it becomes easy to mix with a thermoplastic resin and perform a molding process.
[0022] The calcined product or carbide used in the present invention may be in the form of a molded product. That is, the pulverized starting material (calcined product) of the lignocellulosic biomass is molded into briquettes or pellets. By making it into a molded product, handling becomes easier and the density increases, so the transportation cost can be reduced. The bulk density of the molded product after the densification treatment is preferably 500 kg / m 3 or more, and more preferably 600 kg / m 3 or more. The bulk density can be measured according to 6 "Bulk Density Test Method" of JIS K 2151.
[0023] In the present invention, the apparatus for making the calcined product into a molded product is not particularly limited. For example, a briquetter (manufactured by Kitakawa Iron Works), a ring die pelletizer (manufactured by CPM), a flat die pelletizer (manufactured by Kahl, Dalton), etc. are desirable.
[0024] In the present invention, when making the calcined product or carbide into a molded product, the moisture content of the calcined product is preferably 8 to 50%, and more preferably 10 to 30%. If the moisture is less than 8%, clogging occurs inside the briquetter or pelletizer, and a stable molded product cannot be produced. If the moisture content exceeds 50%, it is difficult to mold, and it is discharged in a powder or paste form.
[0025] In the present invention, a binder may be added to the calcined product or carbide. The binder is not particularly limited. For example, organic polymers such as starch and lignin, inorganic polymers such as acrylamide, and agricultural residues such as bran (residue generated during wheat flour production) can be preferably used. From the viewpoint of efficiently and effectively using lignocellulosic biomass, it is desirable that the number of binder additions is small. Preferably it is 50 parts by mass or less, and more preferably 20 parts by mass or less with respect to 100 parts by mass of the calcined product. However, it is not the case that densification is impossible even if 50 parts by mass or more is added.
[0026] In the present invention, it is preferable to pulverize the roasted or carbide material before kneading it with the thermoplastic resin. The average particle size of the pulverized material or carbide material must be 100 μm or less, and more preferably 50 μm or less. If the average particle size of the pulverized roasted or carbide material is greater than 100 μm, uniform mixing with the resin becomes difficult, and problems may arise such as the resin being finely broken at the outlet of the injection device and difficulty in transferring the mixture of pulverized material and resin to the cooling device. The average particle size is the 50% average particle diameter (D50) measured by the laser light scattering method (laser diffraction method), and can be measured with a laser diffraction / scattering particle size distribution analyzer (Malvern Co., Ltd., instrument name: Mastersizer 2000), etc.
[0027] The pulverizer used when crushing roasted materials can be any device capable of crushing organic matter. For example, but are not limited to these, ball mills, rod mills, bead mills, conical mills, disc mills, edge mills, hammer mills, mortars, pellet mills, VSI mills, Willie mills, roller mills, jet mills, mascolloiders, etc., can be used.
[0028] The molding resin material of the present invention can be obtained by heating and kneading the above-mentioned roasted product, a thermoplastic resin, and an acid-modified polyolefin. In order to achieve a high level of carbon neutrality, a higher proportion of the roasted product in the molding resin material is preferable, but considering the manufacturing and strength of the resulting resin material and molded articles, it is necessary for the proportion to be 10% by mass or more and 90% by mass or less, preferably 20% by mass or more and 90% by mass or less, and more preferably 40% by mass or more and 80% by mass or less.
[0029] In the present invention, polyamide resins such as polyamide 6 (nylon 6, PA6), polyamide 66 (nylon 66, PA66), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 46, polyamide XD10 (PAXD10), and polyamide MXD6 (PAMXD6) can be preferably used.
[0030] In the present invention, thermoplastic resins other than polyamide resins may be used. Examples of thermoplastic resins include polyethylene and polypropylene, but are not limited to these; 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.
[0031] In the present invention, biodegradable resins other than polyamide resins may be used as thermoplastic resins. Examples of thermoplastic biodegradable resins include, but are not limited to, polylactic acid (PLA), polybutylene succinate, polyethylene succinate, polyglycol, polycaprolactone, and polyvinyl alcohol. Furthermore, two or more thermoplastic resins can be used simultaneously.
[0032] In the present invention, by adding a thermoplastic elastomer, it is possible to stably produce a highly viscous molding resin material that does not break or crack during injection molding, even when pulverized woody biomass roasted material is incorporated.
[0033] Examples of thermoplastic elastomers used in the present invention include styrene-based thermoplastic elastomers. More specifically, block copolymers such as styrene-butadiene-styrene (SBS) copolymer, styrene-isoprene-styrene (SIS) copolymer, styrene-ethylene-butylene-styrene (SEBS) copolymer, styrene-ethylene-propylene-styrene (SEPS) copolymer, and styrene-butadiene-butylene-styrene (SBBS) copolymer can be used. These may be used individually or in combination of two or more.
[0034] Furthermore, examples of thermoplastic elastomers used in the present invention include polyolefin-based elastomers. More specifically, examples include ethylene-butene copolymer, EPR (ethylene-propylene copolymer), modified ethylene-butene copolymer, EEA (ethylene-ethyl acrylate copolymer), modified EEA, modified EPR, modified EPDM (ethylene-propylene-diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), modified SEBS (styrene-ethylene-butylene-styrene copolymer), halogenated isobutylene-paramethylstyrene copolymer, ethylene-acrylic acid modified product, ethylene-vinyl acetate copolymer, and acid modified products thereof, as well as mixtures mainly composed of these. These may be used individually or in combination of two or more.
[0035] Preferred thermoplastic elastomers used in the present invention include styrene-butadiene block copolymers, ethylene-octene copolymers, and propylene-ethylene copolymers. Styrene-butadiene block copolymers are particularly preferred. The above thermoplastic elastomers may also be modified with maleic anhydride, fumaric anhydride, or the like. In the case of styrene-butadiene block copolymers, the styrene content is preferably 15 to 30% by mass.
[0036] The blending ratio of the thermoplastic elastomer is preferably 1 to 20% by mass, and more preferably 3 to 10% by mass.
[0037] A molded article can be obtained by heat-treating the molding resin material of the present invention. The temperature when heat-treating (heating, melting, kneading, etc.) the molding resin material of the present invention is usually around 100 to 300°C, preferably around 110 to 250°C, and particularly preferably around 120 to 220°C. The molded article obtained by heat treatment can be molded into the desired shape using conventionally known resin molded articles.
[0038] In the method for producing the molding resin material of the present invention, general equipment used in resin molding can be used to heat and knead the roasted product and the acid-modified polyolefin. For example, a general extruder or a twin-screw compounding extruder can be used. As a twin-screw compounding extruder, the TEX series manufactured by Japan Steel Works can be used.
[0039] Various molded articles can be manufactured using the molding resin material of the present invention. Conventional methods used for molding thermoplastic resins can be used for molding, and for example, but are not limited to, injection molding, extrusion molding, blow molding, die molding, hollow molding, foam molding, etc.
[0040] The molding resin material of the present invention or the molded article obtained by molding it may contain organic and / or inorganic substances other than thermoplastic resin and roasted products. Other components include, for example, alkalis such as sodium hydroxide, potassium hydroxide, 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 or pigments such as red iron oxide, azo pigments, and phthalocyanines; and modifying additives such as dispersants, lubricants, plasticizers, release agents, flame retardants, antioxidants (phenolic antioxidants, phosphorus antioxidants, sulfuric acid antioxidants), antistatic agents, light stabilizers, ultraviolet absorbers, metal deactivators, crystallization accelerators (nucleating agents), foaming agents, crosslinking agents, and antibacterial agents.
[0041] The molding resin material of the present invention can be molded for a variety of purposes and can be used as a substitute for plastic products. Molded articles obtained from the molding resin material of the present invention can be widely applied to, for example, trays, automobile parts, interior parts such as automobile dashboards, aircraft luggage compartments, structural members of transportation equipment, housings for home appliances, electrical appliance components, various containers such as cards and toner containers, building materials, seedling pots, agricultural sheets, writing instruments, wood products, household appliances, straws, cups, toys, sporting goods, port components, building components, generator components, tools, fishing gear, packaging materials, 3D printed objects, pallets, food containers, tableware, cutlery (spoons, forks, etc.), chopsticks, and various sheets. When these products become unnecessary, they will be disposed of as waste, but even if they are incinerated and emit carbon dioxide, for example, the roasted woody biomass that has been incorporated can be treated as not increasing the amount of carbon dioxide in the atmosphere. [Examples]
[0042] The present invention will be described in more detail below with reference to experimental examples, but the present invention is not limited to these examples. Unless otherwise specified, parts and % refer to parts by mass and mass%, and numerical ranges are given including their endpoints.
[0043] Example 1 Eucalyptus eurograndis wood chips were crushed using a disc chipper. After crushing, the chips, ranging in size from 1 to 50 mm, were dried for 3 hours at a hot air temperature of 70°C using a conveyor dryer (manufactured by Alvan Blanch Co., Ltd.) to adjust the moisture content to 10%. Next, a large rotary kiln-type carbonization furnace was used to roast the woody biomass at an oxygen concentration of 1% or less, with the temperature of the wood chips inside the furnace set to 260°C, and with a residence time of 12 minutes. After cooling, the resulting roasted material was ground using a turbo mill (manufactured by Freund Turbo Co., Ltd.) until the average particle size reached 34 μm. Next, the pulverized roasted material and polyamide resin (polyamide 6 (PA6), trade name: 1013B, manufactured by Ube Industries) were mixed in a ratio of 25:75. The mixture was kneaded at 190°C for 6 minutes using a DSM Xplore Compounder 15 (manufactured by Leo Labs), heated in a 190°C heating chamber, molded (9 bar 2s - 11 bar 0.5s - 11 bar 24s), and molded at 40°C to create a dumbbell of resin material for molding. After this, the physical properties were measured. The average particle size of the crushed roasted material was measured using a laser diffraction particle size analyzer (Mastersizer 3000, Malvern), and the 50% particle size based on volume was used as the average particle size.
[0044] Example 2 A molding resin material was manufactured in the same manner as in Example 1, except that the mixing ratio of the pulverized roasted material and the polyamide resin was set to 51:49.
[0045] Example 3 Hardwood char (manufactured by National Carbon Technology) was crushed using a turbo mill (manufactured by Freund Turbo Co., Ltd.) until the average particle size was 7.5 μm. A molding resin material was manufactured in the same manner as in Example 1, except that the mixing ratio of pulverized carbide and polyamide resin was set to 25:75. The average particle size of the pulverized carbide was measured using a laser diffraction particle size analyzer (Mastersizer 3000, Malvern), and the 50% particle size based on volume was used as the average particle size.
[0046] Comparative Example 1 Without adding any pulverized roasted or carbide materials, a molding resin material was manufactured using only polyamide resin in the same manner as in Example 1.
[0047] Tensile tests were performed on the molding resin materials produced in Examples 1-3 and Comparative Example 1 using the following method, and the results are shown in Table 1. [Tensile test]: Dumbbells conforming to JIS K6251 were created using a DSM Xplore Compounder 15 (manufactured by Leo Lab Co., Ltd.), and their properties were measured at a tensile speed of 1 mm / min in accordance with JIS K7161 (Plastics - Test methods for tensile properties).
[0048] [Table 1]
[0049] As shown in Table 1, the molding resin materials of Examples 1 to 3 exhibited elastic modulus and maximum stress equivalent to those of the molding resin material of Comparative Example 1. In particular, Example 2, which had a blending ratio of 51% by mass of the roasted material, showed a high elastic modulus.
Claims
1. A molding resin material containing 10 to 90% by mass of pulverized woody biomass roasted or woody biomass charred material with an average particle size of 100 μm or less, and further containing a polyamide resin.
2. The molding resin material according to claim 1, comprising, as a thermoplastic elastomer, any of a styrene-butadiene block copolymer, an ethylene-octene copolymer, or a propylene-ethylene copolymer.
3. A molding resin material according to any one of claims 1 to 2, further comprising a biodegradable resin.