Resin composition, filler, and method for producing resin composition

Abstract

To provide a resin composition containing a biomass-derived filler having higher performance than conventional ones.SOLUTION: The resin composition is obtained by adding a biomass-derived fibrous material containing an organic substance and an inorganic substance as a filler to a base material resin. The base resin may be a polyolefin, for example a polypropylene polymer. The fibrous material is derived from rice husks (Oryzasativa). The fibrous substance is a tapered fiber separated by a mesh having an opening of 30 μm to 300 μm by sliding rice with chaff. The fibrous substance in the resin composition has a hollow structure. The fibrous substance is added to the polymer in an amount of 10 to 30% by weight.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] In particular, the present invention relates to a resin composition, a filler, and a method for producing a resin composition. [Background technology]

[0002] Conventionally, among plastics (hereinafter referred to as "resins"), polyolefins, polyesters, polyamides, polyphenylene sulfide, polyethers, polyketones, polyether ketones, polyether ether ketones, and the like have been used in a variety of applications from the viewpoint of their properties and characteristics. For example, polypropylene resin (hereinafter referred to as "PP"), a type of polyolefin, has excellent heat resistance, moldability, transparency, and chemical resistance, and is therefore widely used in a variety of applications, including various industrial materials, automobile-related parts, various medical and cosmetic containers, daily necessities, films, fibers, and the like.

[0003] On the other hand, by adding a filler (hereinafter referred to as "filler") or the like to a resin as an additive, it is possible to improve the performance of the resin. In recent years, attempts have been made to use fillers derived from natural biomass as an alternative to industrially produced fillers, as the use of fillers derived from natural biomass is thought to pose less of a burden to the environment in terms of CO2 emissions and waste generation.

[0004] Meanwhile, rice is one of the most important food crops, boasting the fourth highest production volume in the world, with 755.5 million tons of unhulled rice produced in 2019. When this unhulled rice is milled, rice husks account for approximately 22% of the rice's weight. For this reason, there is a need to find effective ways to utilize rice husks, which are rice-derived biomass. Specifically, because rice husks contain silica and cellulose, attempts are being made to utilize them in the following ways:

[0005] Conventionally, Patent Document 1 describes a resin composition in which an inorganic material derived from rice husks is added to a resin either directly or after combustion (hereinafter referred to as "prior art"). According to this prior art resin composition, the flexural modulus is improved by adding a mixture of rice husks and other biofillers as a filler. In other words, it is described that adding rice husks can improve mechanical properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-22453 [Non-patent literature]

[0007] [Non-Patent Document 1] Lyer, et al., “Novel, Synergistic Composites of Polypropylene and Rice Husk Ash: Sustainable Resource Hybrids Prepared by Solid-State Shear Pulverization”, POLYMER COMPOSITES, 2013, 34, p.1211-1221 Summary of the Invention [Problem to be solved by the invention]

[0008] However, referring to Non-Patent Document 1, the silica in rice husks used in conventional technology has a nearly spherical shape. This is because the silica on the surface of the rice husks is used. When such nearly spherical silica is added as a filler to a resin, the elastic modulus of the composite material can be improved, but there is a problem in that the improvement in the tensile properties is insufficient. For this reason, there has been a demand for resin compositions that contain biomass-derived fillers and have higher performance.

[0009] The present invention has been made in view of the above circumstances, and aims to solve the above-mentioned problems. [Means for solving the problem]

[0010] The resin composition of the present invention is a resin composition in which a fibrous material derived from biomass containing organic and inorganic substances is added as a filler to a base resin, and is characterized in that the fibrous material is derived from rice (Oryza sativa) rice bran. The resin composition of the present invention is characterized in that the base resin is a polyolefin. The resin composition of the present invention is characterized in that the fibrous material in the base resin has a hollow structure. The resin composition of the present invention is characterized in that the fibrous material is tapered fibers obtained by sliding rough rice and separating it with a mesh having an opening of 30 μm to 300 μm. The resin composition of the present invention is characterized in that grooves are formed inside the fibrous material. The resin composition of the present invention is characterized in that the fibrous material is added to the base resin in an amount of 10 to 30% by weight. The filler of the present invention is a filler to be added to a base resin, and is a fibrous material derived from biomass containing organic and inorganic substances, characterized in that the fibrous material is derived from rice (Oryza sativa) rice bran. The method for producing a resin composition of the present invention is characterized in that a fibrous material derived from biomass containing organic and inorganic substances is added to a base resin and kneaded in a high-temperature, high-pressure environment, and the fibrous material is derived from rice (Oryza sativa) rice bran. [Effects of the Invention]

[0011] According to the present invention, by adding a fibrous material derived from rice (Oryza sativa) rice bran, which is derived from biomass containing organic and inorganic substances, as a filler to a base resin, it is possible to provide a resin composition with higher performance than conventional resin compositions, which improves both the elastic properties and strength properties of the composite material. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a conceptual diagram of a filler according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the measurement of the aspect ratio of a filler according to an embodiment of the present invention. [Figure 3A] 1 is a photograph of fibrous material on the surface of rice grains according to an embodiment of the present invention. [Figure 3B] 1 is a photograph of a filler after separation according to an example of the present invention. [Figure 3C] 3C is a photograph showing an enlarged observation of the filler in FIG. 3B. [Figure 3D] 3C is a photograph of the cross section of the filler of FIG. 3B observed by SEM. [Figure 4] 1 is a graph showing the results of XRD of a filler according to an example of the present invention. [Figure 5] 1 is a graph showing the results of TPD-MS of a filler according to an example of the present invention. [Figure 6] 1 is a graph showing a stress-strain curve of a composite material containing 5% MAPP according to an embodiment of the present invention. [Figure 7] 1 is a graph showing the effect of filler content on the elastic modulus of a composite according to an embodiment of the present invention. [Figure 8] 1 is a graph showing the effect of filler content on the tensile strength of a composite according to an embodiment of the present invention. [Figure 9] 1 is a graph showing the effect of filler content on the impact strength of a composite according to an embodiment of the present invention. [Figure 10A] 1 is a graph showing an IR spectrum of a cross section of Test Example 1 according to an embodiment of the present invention. [Figure 10B] 10B is a photograph showing the measurement points of the IR spectrum of FIG. 10A. [Figure 11] 1 is a graph showing thermal property evaluation of a composite material according to an example of the present invention. [Figure 12A] 1 is a photograph showing a cross-sectional direction of a dumbbell-shaped composite material according to an example of the present invention. [Figure 12B]1 is a photograph of the AA cross section of an X-ray CT image of a dumbbell-shaped composite material according to an example of the present invention before a tensile test. [Figure 12C] 10 is a photograph of a BB cross section of an X-ray CT image of a dumbbell-shaped composite material according to an example of the present invention before a tensile test. [Figure 12D] 10 is a photograph of the AA cross section of an X-ray CT image of a dumbbell-shaped composite material according to an example of the present invention after a tensile test. [Figure 12E] 10 is a photograph of a BB cross section of an X-ray CT image of a dumbbell-shaped composite material according to an example of the present invention after a tensile test. [Figure 13A] 1 is a photograph of a cross section of a filler according to an example of the present invention, observed by SEM. [Figure 13B] 1 is a photograph of elemental analysis (carbon) of a filler according to an example of the present invention. [Figure 13C] 1 is a photograph of elemental analysis (oxygen) of a filler according to an example of the present invention. [Figure 13D] 1 is a photograph of elemental analysis (silicon) of a filler according to an example of the present invention. [Figure 14] 1 is a graph showing the results of Raman analysis of a filler and a composite material according to an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Embodiment> Conventionally, the silica in rice husks has a nearly spherical shape when viewed in microscopic photographs, etc., so when nearly spherical silica is added to a resin as a filler, the elastic modulus of the composite material can be improved, but there is a problem in that the improvement in its tensile properties is insufficient. For this reason, the inventors focused on a substance derived from rice grains that contains fibrous silica (hereinafter referred to as "fibrous substance") and discovered that adding this as a filler to PP improves adhesion to the resin through surface modification, and also improves various properties including not only the elastic modulus but also the tensile properties through the formation of an air layer, thereby completing the present invention.

[0014] FIG. 1 illustrates an outline of a composite material of PP and filler (PP composite material or composite; hereinafter, simply referred to as "composite material"), which is an example of a resin composition according to this embodiment. In this embodiment, the composite material is composed of a resin and a fibrous material derived from rice grains, and the boundary between them is tightly adhered with no gaps. Meanwhile, although there are air gaps inside the fibrous material, the resin can be seen to have penetrated into it. In this way, the fibrous material derived from rice grains comes into contact with the resin on both the outer and inner surfaces, which makes it possible to improve both the elasticity and strength properties of the composite material. The resin composition, filler, and method for producing the resin composition according to this embodiment will be described in detail below, but the present invention is not limited thereto.

[0015] (Resin composition and filler) The resin composition according to this embodiment is a resin composition in which a fibrous material derived from biomass containing organic and inorganic substances is added as a filler to a base resin, and the fibrous material is derived from rice (Oryza sativa) rice grains.

[0016] Here, the base resin according to the present embodiment may be various resins produced from petroleum products, such as polyolefin, polyester, polyamide, polyphenylene sulfide, polyether, polyketone, polyether ketone, and polyether ether ketone, biologically derived resins, and other biodegradable resins. In this embodiment, an example will be described in which the base resin is a polymer of PP, a type of polyolefin. This PP can be any of three types of PP known primarily in the form of copolymerization with a comonomer such as ethylene, such as homo-, random-, or block-type, or a mixture of these. It is also possible to use either or both of isotactic PP and syndiotactic PP, which have different crystallinity. Alternatively, modified propylene such as maleic acid-modified polypropylene (MAPP) can also be used.

[0017] However, the base resin is not limited to these, and various resins other than PP can also be used as the resin according to this embodiment. For example, the present inventors have confirmed that polyester-based polybutylene terephthalate resin (hereinafter referred to as "PBT") can also produce composite characteristics such as a hollow structure, which will be described later, similar to those of PP.

[0018] The fibrous material according to this embodiment may be a fibrous material derived from rice husks (hereinafter, also simply referred to as "fiber"). Specifically, the fibrous material of this embodiment may be a protruding material on the surface of rice grains, as shown in Figure 3A in the Examples described later. Most of this protruding material falls off the grains before the grains are separated into brown rice and husks. Therefore, it is rarely found in ordinary rice husks. On the other hand, the composition of this material is not significantly different from silica derived from rice husks in the prior art, and it contains both organic and inorganic substances. Specifically, as shown by SEM observation and elemental analysis in the Examples described later, it is composed of woody components such as cellulose and inorganic components such as silica.

[0019] More specifically, the fibrous material according to this embodiment is preferably obtained by sliding unhulled rice before threshing and separating it with a mesh having openings of 30 μm to 300 μm. In this embodiment, this fibrous material can be used as a filler to be contained in the resin.

[0020] In this embodiment, the fibrous material has a hollow structure and a tapered (cone-shaped) shape, as will be shown in the examples described later. This tapered shape may have an aspect ratio of, for example, about 10 to 30. The aspect ratio, determined from the length and diameter of the filler, is one of the important factors affecting the tensile properties of composite materials. Therefore, by using fillers with an appropriate aspect ratio, it is possible to improve the tensile properties of composite materials.

[0021] Here, the resin composition according to this embodiment is characterized in that grooves are formed only inside the fibrous material. Specifically, in this embodiment, by kneading the filler and resin under a high-temperature and high-pressure environment as described below, it is possible to form spike-shaped grooves only on the inner surface of the filler. The resin penetrates into these internally formed grooves, which increases the contact area between the resin and the filler and also improves strength through an anchor effect. In other words, it is believed that the penetration of the resin into the internal grooves increases the interfacial area and increases the strength of the composite material.

[0022] Conversely, the resin composition according to this embodiment is also characterized in that no grooves are formed on the outer surface of the fibrous material. That is, it is presumed that, because the fibrous material has a hollow structure, no grooves are formed on the outside when compressed. Assuming that an interface with the resin is formed in the grooves on the outer surface, it may increase the strength in terms of the contact area, but when an external force is applied, the force is applied directly to the grooves, causing cracks to expand, which may result in the formation of voids. In contrast, the fibrous material of the resin composition according to this embodiment is suitable because it does not have grooves on the outside and therefore does not cause such void formation. Therefore, when an external force is applied, there are no grooves on the outer surface of the filler, and the structure is maintained only by adhesion force. Therefore, there is little possibility that the internal structure will be affected.

[0023] In this embodiment, the fibrous material is preferably added to the resin in an amount of 10 to 30% by weight. If the amount is less than 10% or more than 30%, it is not possible to sufficiently improve both the elasticity and strength characteristics. Furthermore, this addition rate can be adjusted appropriately between 10 and 30% by weight depending on which of the stress-strain, elastic modulus, and tensile strength characteristics is prioritized. Furthermore, 3 to 5% by weight of MAPP may be added as shown in the examples below.

[0024] (Resin composition manufacturing method) In this embodiment, the above-mentioned fibrous material is added to a resin containing a PP polymer, and the mixture is kneaded in a high-temperature, high-pressure environment, thereby making it possible to manufacture a composite material.

[0025] Specifically, in this embodiment, the filler can be modified by kneading a fibrous material derived from rice grains with a resin under a high-temperature and high-pressure environment and molding the mixture. As described above, the fibrous material derived from rice grains used as a filler contains organic and inorganic materials. When kneading, the fibrous material is heated to a temperature above the melting point of the resin using a kneader or the like, and kneaded into a liquid resin.

[0026] In this embodiment, the "high-temperature, high-pressure environment" may be an environment at a temperature equal to or higher than the melting point of the resin, for example, 100 to 300°C, and a pressure of about 0.5 MPa to 4 MPa. More specifically, it may be an environment at 180 to 250°C and 1 to 3 MPa. Under these conditions, the wood components (organic matter) such as cellulose in the fibrous material are gasified by pyrolysis. In the examples described below, it is shown that during pyrolysis, water vapor is generated first, followed by carbon dioxide and carbon monoxide. The reaction between these gas components and the filler leads to the modification of the filler itself.

[0027] In this embodiment, as described above, the filler is modified by the alteration of the organic matter due to thermal decomposition in a high-temperature, high-pressure environment. Specifically, since there is very little oxygen mixed in during kneading and molding, the woody components on the filler surface tend to graphitize (carbonize) in a temperature environment of 200°C or higher, and more significantly at 300°C or higher. In this embodiment, as will be explained in the examples below, the filler may be modified so that graphitization does not proceed. Furthermore, by modifying the filler surface from its initial state, compatibility with PP and MAPP (maleic anhydride modified polypropylene) changes, making it possible to increase adhesion.

[0028] Furthermore, the fibrous material according to this embodiment has a tapered hollow structure as described above, and the outer and inner surfaces of the filler come into contact with the resin during resin mixing and molding, which is expected to improve physical adhesion with the resin.

[0029] Here, when kneading at normal pressure, it is usually assumed that the molten polymer penetrates into the fibrous material. In particular, when the diameter of the fibrous material is about 10 μm, it is thought that the resin melt penetrates into the fibrous material due to capillary action.

[0030] In contrast, the production of the resin composition according to this embodiment is characterized in that the filler is made hollow by kneading in a high-temperature, high-pressure environment. Specifically, by increasing the pressure (total pressure) during mixing to a high-temperature, high-pressure environment, the intrusion of resin into the fibrous material can be suppressed, resulting in hollow spaces. That is, the pressure of the air that was present inside the fibrous material before the filler and resin were mixed can be increased by placing the mixture of filler and resin in a high-temperature, high-pressure environment. This suppresses the intrusion of molten resin, making it possible to form spaces within the filler.

[0031] The air in the space inside the filler is thought to be in a state where it maintains pressure in the high-temperature, high-pressure environment during kneading and molding. This can act as a damper against external forces, such as compression. This is expected to be effective in preventing "filler crushing." In other words, this space can contribute to improving both the elasticity and strength properties of the composite material.

[0032] Furthermore, the resin composition according to this embodiment is characterized in that grooves are formed inside the fibrous material during production. That is, by kneading and molding the resin composition under a high-temperature, high-pressure environment, the fibrous material according to this embodiment can form spike-shaped grooves only inside the material. This is presumably because, as described above, the fibrous material according to this embodiment has a tapered (cone-shaped) hollow structure, and is subjected to external compressive stress when placed in a high-temperature, high-pressure environment during kneading, resulting in the formation of spike-shaped grooves.

[0033] By manufacturing in this manner, it is possible to improve both the elasticity and strength of the composite material. Here, in this embodiment, "improving both the elasticity and strength" may mean that the elasticity and strength of the composite material to which the filler is added are increased compared to the elasticity and strength of the kneaded resin alone.

[0034] The resin composition according to this embodiment can be molded into a desired shape by pressure molding, film molding, vacuum molding, extrusion molding, injection molding, or the like, either after being kneaded into pellets or without being kneaded. Furthermore, the resin composition according to this embodiment can be used as various industrial materials, parts materials, recreational materials, sports materials, electrical insulating materials, agricultural and fishery materials, construction materials, automobile-related parts, various medical and cosmetic containers, daily necessities, furniture, chassis of home appliances, housings, films, fibers, and the like.

[0035] The above configuration can provide the following effects. In the resin compositions of the prior art, the silica in rice husks was found to have a nearly spherical shape, based on microscopic photographs in publications and papers. When the silica used is nearly spherical, its aspect ratio is small, and adding it to a resin can improve the elastic modulus of the composite material, but there is a problem in that the improvement in its tensile properties is insufficient.

[0036] Furthermore, the strength of a composite material containing a filler is determined not only by its morphology, but also by the chemical and physical state of the interface with the resin. At the interface between a resin with weak chemical bonding strength and a filler with a smooth surface, the application of force can weaken the adhesion and cause voids. These voids are undesirable because they can cause cracks.

[0037] In contrast, according to the present embodiment, fibrous material derived from rice grains is used as a filler and mixed with resin in a high-temperature, high-pressure environment, thereby modifying the surface to allow adhesion with the polymer, forming grooves inside, and forming internal spaces. This makes it possible to provide a resin composition as a high-strength composite material that has improved properties in both elasticity and strength, for example, by providing a physically excellent surface structure that increases the specific surface area of ​​the filler surface through an anchor structure or the like.

[0038] In the above-described embodiment, the orientation of the resin composition during molding is not described. However, by orienting the tapered shape of the fibers when kneading and molding the fibrous material, it is possible to further improve both the elasticity and strength properties.

[0039] Furthermore, in the resin composition according to the present embodiment, compositions other than fillers can also be used as appropriate depending on the application of the product, etc. For example, a compatibilizer commonly used by those skilled in the art can be used to enhance the adhesive effect between the filler and the resin. Furthermore, the addition of an antioxidant can prevent deterioration of the resin composition. The addition of a colorant can adjust the color tone of the resin and enhance its mechanical strength. Furthermore, a lubricant or the like may be added as needed to improve processability. Additionally, paraffin oil or the like may be used as a dispersant.

[0040] In the above embodiment, an example in which rice fibrous material is used has been described. The rice may be normal edible rice that is threshed, or may be an improved variety of rice that has a large amount of fibrous material outside the seed. Alternatively, it is possible to use seeds of other grasses containing silica projections, which are used for biomass as rice bran.

[0041] Next, the present invention will be further described by way of examples with reference to the drawings, but the present invention is not limited to the following specific examples. [Example]

[0042] [Production of Filler, Test Examples, and Comparative Examples] (filler) To extract fibrous material from rice husks, we prepared by-products discharged from or accumulated around rice dryers in southern Akita Prefecture. Microscopic examination revealed that the by-products consisted primarily of fibrous silica. The by-products were gradually separated using a screen with mesh sizes of 53 μm to 300 μm (manufactured by Toyo Screen Kogyo Co., Ltd.). After removing large particles, the by-products were passed through a stainless steel mesh with mesh sizes of 30 μm (manufactured by Kureha Co., Ltd.) to remove small particles. The fibrous silica remaining on the stainless steel mesh was used as the fibrous material and filler in this study.

[0043] (Test Example 1) For Test Example 1, dumbbell-shaped composite test pieces (hereinafter simply referred to as "dumbbells") were prepared. These composites were manufactured using a twin-screw extruder (KZX25TW-60MG-NH (1200), manufactured by Technobel Co., Ltd.). The length / diameter ratio inside the barrel was 60. The composite temperature was 180°C. The screw rotation speed was 100 rpm. The twin-screw extruder was used to directly mix PP and filler, and MAPP (maleic anhydride-modified polypropylene) treatment was also performed at 1, 3, and 5 wt% of the PP content. Dumbbell-shaped test pieces according to JIS K 7162 1BA were manufactured using an injection molding machine (NP-1F, manufactured by Nissei Plastic Industrial Co., Ltd.). In an injection molding machine or extruder, the barrel (cylinder), which is a cylindrical housing for housing a plunger or rotating screw, consisted of five heating zones. The mold temperature was 30°C. The injection speed was 17.6 mm / s. The filler content of the composites was 10 wt%, respectively. Before compounding and molding the composites, the materials were dried in an oven at 80 °C for 8 h.

[0044] (Test Example 2) As Test Example 2, dumbbells were prepared using composite materials with different compositions in the same manner as Test Example 1. The filler content of each composite material was 20 wt %.

[0045] (Test Example 3) As Test Example 3, dumbbells were prepared using composite materials with different compositions in the same manner as Test Examples 1 and 2. The filler content of each composite material was 30 wt %.

[0046] (Comparative Example) As a comparative example, a dumbbell made of only PP was prepared in the same manner as in Test Examples 1 to 3.

[0047] [Evaluation method] (Measurement of the morphology of fibrous materials derived from rice) To evaluate the morphology of the isolated fillers, the fillers were covered with a cover glass and observed using an inverted microscope (CKX41, Olympus Corporation). A 10x objective lens was used. A CCD camera (HD CE 30C, AS ONE Corp.) was used for imaging. The fiber length and upper and lower diameters of the fibrous material were measured using an image processing program (Image J, National Institutes of Health, USA). Using this method, 100 replicate fillers were measured.

[0048] Referring to FIG. 2, to measure the morphological parameters of the filler, the aspect ratio of the filler was defined as follows: Aspect ragio = 2×L f / (D t +D b )... Equation (1) where Lf represents the fiber length of the filler, and D t is the diameter of the top of the filler, D b represents the diameter of the bottom of the filler.

[0049] (mechanical property evaluation) Tensile tests were performed using a tensile testing machine (Series 3360, Instron Corp.) in accordance with JIS K 7113. The results of these experiments were described in terms of nominal stress and nominal strain calculated from the load and distance between the crossheads of the tensile testing machine. All experiments were performed at room temperature (23 ± 2°C) at a test speed of 10 mm / min. Five samples were used per test condition. The elastic modulus was calculated using the change in tensile stress versus strain from 0.5 to 1.0. The impact strength of PP and PP composites was measured using notched Charpy test specimens in accordance with JIS K 7111-1. Impact tests were performed using an impact testing machine (Toyo Seiki Seisakusho) with a 7.5 J hammer.

[0050] (Fourier transform infrared spectroscopy (FT-IR)) Before measuring the infrared spectrum of the PP composite, 5 μm-thick slices were cut from the dumbbell specimens using a rotary microtome (RM2135, Leica). IR spectra were then measured using a Nicolet iN10 MX (Thermo Fisher Scientific) in transmission mode with a mapping scan. The wavenumber resolution was 4 cm. -1 The number of scans was 32.

[0051] (Thermal characteristic evaluation) Thermogravimetry differential thermal analysis (TG DTA) was performed in a nitrogen atmosphere using a DTG 60 (Shimadzu Corporation) at a temperature increase rate of 10°C min from room temperature to 600°C. -1 The measurements were carried out under the following conditions. The PP sample of the comparative example and the composite samples of Test Examples 1 to 3 were prepared from the dumbbell samples using nippers. The samples had a mass of approximately 10 mg and were dried in a thermostatic chamber at 80°C for 8 hours before being subjected to measurement. An open aluminum pan was used for all evaluations. The temperature at which a 5% weight loss was observed was defined as the decomposition temperature (Td). All of these experimental conditions were in accordance with JIS K 7120.

[0052] (thermal diffusivity measurement) Using a laser flash analyzer (LFA 457 MicroFlash, manufactured by NETZSCH), thermal diffusivity measurements were performed on dumbbell samples of PP and composite materials using the laser flash method. As a pretreatment, dumbbell samples were cut from near the center of the dumbbell, measuring approximately 2 mm x 2 mm x 0.5-1 mmt, in the a direction and perpendicular to that in the b direction, and then used for measurement. The PP sample of the comparative example without silica had higher transparency than Examples 1-3, which contained silica. For this reason, the comparative example was subjected to a blackening treatment by vapor-depositing an anti-transmission film on the cut pieces. The measurement temperature was 25°C, and the measurement atmosphere gas was He.

[0053] (X-ray CT device) An object was scanned using X-rays with a computed tomography (CT) device (X-CT), and the images were converted into three-dimensional data including the inside and outside of the object through computer processing. The X-CT device used was installed on beamline BL11S3 at the Aichi Synchrotron Center. The device conditions were as follows: Beam mode: Direct (white) Attenuator: Aluminum, 1mm Scan angle: 185° Step angle: 0.1° Measurement number: 1850 Exposure time: 200msec Camera: Orca-Flash 4.0v3 (Hamamatsu Photonics) Beam monitor: AA50 (Hamamatsu Photonics) Measurement magnification: 10x (pixel size 1.33 μm / voxel), 20x (pixel size 0.65 μm / voxel) Scintillator: LuAG 10 μm

[0054] (Raman measurement equipment) Raman measurements were performed on PP and its composites. Raman spectroscopy was performed using a confocal Raman microscope (InVia Qontor, Renishaw, UK) with an excitation wavelength of 532 nm. The measurement temperature was 20 to 25°C.

[0055] (X-ray diffraction method (XRD)) Crystallographic analysis of the fibrous materials and dumbbells was performed by X-ray diffraction (XRD) at the Aichi Synchrotron Radiation Center (Aichi Synchrotron Radiation Center) on beamline BL8S1. The fibrous materials were measured in powder form, and the composites were measured in dumbbell form. For the dumbbells, XRD measurements were performed in transmission mode with the long side (tensile direction) facing upward and the dumbbell width perpendicular to the incident X-ray beam. The X-ray wavelength was 0.863 Å, the photon energy was 14.37 keV, and the beam spot size was 0.2 mm × 0.5 mm. Diffraction patterns were measured using a two-dimensional detector (PILATUS-100 K, DECTRIS LTD, Switzerland).

[0056] (SEM and EDS analysis) For observations using a scanning electron microscope (SEM), Pt (4 nm) was deposited on the Schottky sample surface, and then the sample was observed using a Schottky field emission scanning electron microscope JSM-7800F (SHL) (manufactured by JEOL Ltd.). The detector used was a lower secondary electron detector, in the super hybrid lens version (SHL) mode with charge suppression function, at a working distance of 3 mm, an accelerating voltage of 1.5 kV, and a probe current of 80 pA. Energy-dispersive X-ray spectroscopy (EDS) analysis was also performed, and carbon, oxygen, and silicon were visualized primarily in elemental maps.

[0057] 〔result〕 (Measurement of the morphology of fibrous materials derived from rice) The morphology of the fibrous material derived from rice was observed under a microscope and measured. 3A is a micrograph of the fibrous material on the surface of the rice grains. The arrow indicates the fibrous material of this example, which will become the filler after separation. FIG. 3B is a photomicrograph of the fibrous material separated by a steel mesh. Figure 3C shows a magnified photograph of the fibrous material after separation in Figure 3B, which reveals a hollow horn shape. Figure 3D is an SEM image of the cross section of the fibrous material after separation in Figure 3B. This photograph shows a cross-sectional SEM taken in a direction perpendicular to the longitudinal direction. This sample was embedded in resin before the cross section was prepared. Since it has a hollow horn shape, a doughnut-like cross section can be seen.

[0058] Table 1 below shows the results of measuring the morphological parameters of the fibrous material shown in FIG.

[0059] [Table 1]

[0060] The average fiber length, top diameter, bottom diameter, and aspect ratio of the fibrous material were 368 μm, 9 μm, 31 μm, and 18.4, respectively. These results also indicate that the fibrous material is a tapered fiber. The diameter of the fibrous material also varies depending on the fiber end of the fibrous silica, with the thicker end being thought to be the original surface side of the pulp. Furthermore, considering the average bottom diameter of 31 μm and its small standard deviation, it was found that the average bottom diameter of the separated fibrous silica was adjusted by the screen opening size (30 μm).

[0061] (XRD of fibrous material) Figure 4 shows the XRD results for the filler, a fibrous material derived from rice. The horizontal axis represents the angle (°), and the vertical axis represents the Intensity / au value. The dashed line represents the results for the untreated filler, and the solid line represents the results for the filler after heat treatment (300°C). Because the filler is a natural material, it exhibits an amorphous-like XRD pattern, but spike-like peaks indicating crystallinity can be confirmed. These peaks do not disappear even after heat treatment up to 300°C. This means that these peaks are not considered to be organic wood components such as cellulose. The 2θ angles of these peaks were 17.4, 21.5, 26.7, 29.4, and 34.8°, respectively. These peaks can be used as indicators of the presence of fillers derived from rice paddy.

[0062] (Thermal evolved gas analysis (TPD-MS)) The results of TPD-MS of the fibrous material (filler) derived from rice are shown in Figure 5. The horizontal axis represents temperature (T / °C) and the vertical axis represents evaporation rate. The results of TPD-MS showed that the gas generated at around 50°C was water vapor, which is thought to be water that had been physically adsorbed within the filler. Upon further heating, water vapor was confirmed to be generated again at around 130°C, followed by the generation of gases presumably from organic components such as carbon dioxide and carbon monoxide. The generation of these gases is thought to be due to the decomposition of wood-based organic matter in the filler.

[0063] (mechanical property evaluation) (stress strain) Figure 6 shows typical stress-strain curves for PP and composites containing 5% MAPP. The horizontal axis represents nominal strain ε, and the vertical axis represents nominal stress σ (MPa). The comparative example shows PP and MAPP only, test example 1 shows the same example as in this example, with 10 wt% filler plus PP and MAPP, test example 2 shows 20 wt% filler plus PP and MAPP, and test example 3 shows 30 wt% filler plus PP and MAPP.

[0064] The fracture strain of the composites with different filler contents in Test Examples 1 to 3 was similar to that of the untreated state. Furthermore, the ductility of the composites containing MAPP in Test Examples 1 to 3 was suppressed as the filler content increased. On the other hand, the tensile strength of the composites containing MAPP improved as the filler content increased. Furthermore, these tensile strengths were all higher than the tensile strength of the comparative example (a matrix of PP alone to which MAPP had been added) that was subjected to MAPP treatment.

[0065] (elastic modulus) Figure 7 shows the effect of filler content on the elastic modulus of the composite. The horizontal axis represents the filler content, and the vertical axis represents the elastic modulus (GPa). Here, the effect of MAPP content was also taken into consideration, and values ​​were measured for 0 to 5%. In Test Examples 1, 2, and 3, the elastic moduli of composites containing 10, 20, and 30 wt% filler without MAPP were 698.0, 923.4, 1165.0, and 1310.4 MPa, respectively. The elastic moduli of the composites increased linearly with filler loading. The elastic moduli of the composites increased by up to approximately 88% compared to the elastic modulus of the comparative example containing 0 wt% filler. While the mechanical properties of PP composites were improved by filling 30% block silica with conventional techniques, the improvement in this example was statistically significant compared to these conventional techniques.

[0066] Furthermore, the composites containing MAPP (MAPP-treated) showed higher moduli than those without MAPP treatment (0% MAPP) at each filler loading. In Test Examples 1, 2, and 3, the moduli increased by 102.9, 119.9, and 128.8 MPa when 10, 20, and 30 wt% of filler was added and 3% of MAPP was added, respectively. Furthermore, when comparing composites containing 3wt% and 5wt% MAPP, no significant difference was observed in the modulus of elasticity, which is thought to be due to the saturation of the effect of MAPP.

[0067] (tensile strength) Figure 8 shows the effect of filler content on the tensile strength of the composite. The horizontal axis represents the filler content, and the vertical axis represents the tensile strength (MPa). Values ​​were also measured for MAPP contents of 0 to 5%.

[0068] The composite materials containing no MAPP in Test Examples 1 to 3 showed increased tensile strength as the filler content increased, although this was not statistically significant compared to the comparative example containing only PP. The increase in tensile strength of the composites with increasing filler content was not linear. The tensile strength of the composites filled with 3 wt% and 5 wt% MAPP increased with increasing filler content. The tensile strength was higher than that of the PP-only control and the composite filled with 1 wt% MAPP.

[0069] Furthermore, when comparing composites filled with 3 wt% and 5 wt% MAPP, no significant difference in tensile strength was observed, suggesting that the effect of MAPP had saturated. However, despite this saturation of the effect of MAPP, when the silica loading was increased to 30%, the composites showed an increase in tensile strength. This result indicates that the filler functioned as a reinforcing fiber.

[0070] (Impact strength) Figure 9 shows the effect of filler content on the impact strength of composites. The composites without MAPP (Test Examples 1 to 3) exhibited linearly higher impact strength as the filler content increased compared to the comparative example containing only PP. This result indicates that the filler is also an excellent fiber for impact absorption. Therefore, the improvement in not only the tensile strength but also the impact strength of the composite demonstrates the effectiveness of the filler as a reinforcing fiber.

[0071] Furthermore, when MAPP was added to Test Examples 1 to 3, the impact strength of the composite material at each filler content was higher. These results demonstrate that adding MAPP to PP composite materials is effective in improving not only tensile strength but also impact strength. On the other hand, no significant difference was observed between the composites filled with 3 wt% and 5 wt% MAPP, suggesting that the appropriate amount of MAPP added to the composite is up to 5%. In addition, since the rate of increase in impact strength decreased in composites with a high filler content, it is thought that a filler content of around 30% is appropriate for increasing impact strength.

[0072] (Fourier transform infrared spectroscopy (FT-IR)) Figure 10A shows the IR spectrum of the composite material in which 10 wt% of the filler of Test Example 1 was added to PP. "a" is the PP, "b" is the filler, and "c" is the IR spectrum at the measurement point inside the filler. The horizontal axis is the wavelength (cm -1 ), and the vertical axis of each shows Absorbance (au). FIG. 10B shows the measurement points "a" to "c".

[0073] The IR spectrum of PP “a” shows wavenumbers of 3000–2800 and 1500–1300 cm -1 Two peaks were detected at 1170, 970, and 840 cm -1 These peaks are thought to represent the functional groups derived from PP and its main skeleton, respectively. In the IR spectrum of filler "b", 3700 to 3100 cm -1 A broad peak was observed around 1170 cm, which is due to the stretching vibration of the hydroxyl group (OH) derived from the cyanol group (SiOH). -1 and 810cm -1 The two small peaks are due to the stretching vibrations of SiO and SiC, respectively. In the IR spectrum of the filler interior of "c", the characteristic peak seen in the filler spectrum was also observed inside. -1 A broad peak was observed around this area, which is thought to be due to cellulose and hemicellulose, which are the main components of rice husk.

[0074] (Thermal characteristic evaluation) The TG curves of the filler and composite material are shown in Figure 11. The horizontal axis represents temperature (°C) and the vertical axis represents weight (%). The TG curve is a thermogravimetric technique that shows the thermal decomposition behavior of fillers and composites. The initial decomposition of the filler occurred around 60°C, followed by weight loss at 270-400°C. The initial weight loss corresponded to the heat of vaporization of water from the filler shown in Figure 5 above. The decomposition product here is likely to be cellulose, based on the IR results as well. The TG curve of PP showed rapid thermal decomposition between 350 and 450°C, followed by a weight loss of approximately 99.8% at 600°C. The thermal decomposition behavior of composites containing 10, 20, and 30 wt% filler was similar. The weight loss of the composites at 600°C depended on the filler concentration.

[0075] Table 2 below shows the decomposition temperatures (Td) corresponding to a 5% weight loss of the filler and composite material when the wt% of the PP and filler blend is changed.

[0076] [Table 2]

[0077] Specifically, Table 2 shows the Td, wt% at 600°C, and melting point (Tm) when the filler (wt) / PP (wt) ratio is changed. As a result, the Td of the filler was about 293°C, while the Td of the composites with 10, 20, and 30 wt% filler additions were 371, 350, and 336°C, respectively.

[0078] (thermal diffusivity measurement) The thermal diffusivity measurements of the dumbbell-shaped composites are shown in Table 3 below.

[0079] [Table 3]

[0080] In Table 3, the a direction is the length direction (tensile direction) of the dumbbell, and the perpendicular direction is the b direction. "Without filler" is a comparative example using only PP, and "With filler" is Test Example 3 with a filler content of 30 wt% to which 5 wt% MAPP was added. The thermal diffusivity showed a tendency to increase in both the a-direction and the b-direction compared to the comparative example without filler. The increase rate in the a-direction was particularly high.

[0081] (X-ray CT device (X-CT)) 12A shows an example of a sample formed as a dumbbell-shaped composite material by adding 5 wt% MAPP to a filler loading rate of 30 wt% in Test Example 3. X-CT images were taken of the AA and BB cross sections of this dumbbell-shaped sample. FIG. 12B is an image of the AA cross section of the sample before the tensile test. FIG. 12C is an image of the BB cross section of the sample before the tensile test. FIG. 12D is an image of the AA cross section of the sample after the tensile test. FIG. 12E is an image of the BB cross section of the sample after the tensile test.

[0082] In the AA cross-section images of Figures 12B and 12D, the fact that many circular fillers are visible indicates that they are oriented in the direction of the BB cross-section, which is perpendicular to the AA cross-section. Also, in the images, the areas that appear darker than the resin color are thought to be air layers. Furthermore, although the hollow structure of the filler is cone-shaped, CT images reveal that there are fillers with openings on both sides, although not many. This is thought to be because the tip of the hollow held by the filler breaks during the kneading and molding processes, exposing a new hollow space. The resin then penetrates into this new hollow space, that is, from both ends of the filler, creating an anchor effect. This is thought to be one of the reasons for the increase in strength due to the addition of fillers.

[0083] (Cross-sectional SEM observation and elemental analysis (ESD)) Cross-sectional SEM and ESD images of the composite material are shown in FIGS. 13A to 13D. FIG. 13A is an SEM image. FIG. 13B is an EDS image of elemental carbon. FIG. 13C is an EDS image of oxygen element. FIG. 13D is an EDS image of elemental silicon.

[0084] The lighter (whittier) the shading seen in the ESD images, the higher the concentration of that element. The bars in the upper right corner of each image correspond to the element concentration relationship. For example, in FIG. 13B, the area marked "P" is lighter in color than the circular area, indicating a high concentration of carbon, and can be said to be resin. On the other hand, Figures 13C and 13D show that there is a large amount of both oxygen and silicon inside and outside the circular structure. This indicates that this part is silicon oxide (silica). Therefore, this photograph can be said to show the cross section of the filler. A characteristic structure of the composite material of this example is that spike-shaped cracks run from the inside of the filler. On the other hand, no such cracks were found in the cross section of the filler alone shown in Figure 3D. The area indicated by the arrow in Figure 13B shows a high carbon concentration within the crack, which indicates that resin has penetrated into the crack.

[0085] (Raman measurement results) Figure 14 shows the Raman spectra of the filler after heat treatment in N2 at 300 °C and the filler surface inside the dumbbell-shaped composite. The horizontal axis is the Raman shift / cm -1 The vertical axis represents the number of counts. Here, the surface of the filler inside the dumbbell-shaped composite was observed by forming a cross section of the dumbbell-shaped composite without heat treatment, and observing the surface of the filler protruding from the cross section. The surface of the filler after heat treatment in N2 exhibits a G band (1600 cm) derived from the graphite structure. -1 ) peak. This indicates that the reaction of producing carbon with a graphite structure is progressing on the filler surface due to the modification and pyrolysis caused by the gas generated during the pyrolysis of the above-mentioned woody organic matter. On the other hand, no peak corresponding to graphitization was observed on the surface of the filler in the dumbbell-shaped composite. Therefore, although the composite was kneaded with PP and had the necessary heat and pressure conditions in the injection molding machine, it could be said that the formation of a graphite structure had not progressed.

[0086] It goes without saying that the configurations and operations of the above-described embodiments are merely examples, and can be modified as appropriate within the scope of the present invention. [Industrial Applicability]

[0087] The present invention can be applied industrially by using rice husk filler as a high-performance material that can be added to resin.

Claims

1. A resin composition in which a fibrous material derived from biomass containing organic and inorganic substances is added as a filler to a base resin, The fibrous material is derived from rice (Oryza sativa) rice bran. A resin composition characterized by:

2. The base resin is a polyolefin The resin composition according to claim 1 .

3. The fibrous material in the base resin has a hollow structure. The resin composition according to claim 1 .

4. The fibrous material is a tapered fiber obtained by sliding hulled rice and separating it with a mesh having an opening of 30 μm to 300 μm. The resin composition according to claim 3 .

5. A groove is formed inside the fibrous material. The resin composition according to claim 4.

6. The fibrous material is added to the base resin in an amount of 10 to 30% by weight. The resin composition according to claim 1 .

7. A filler added to a base resin, It is a fibrous material derived from biomass containing organic and inorganic substances, The fibrous material is derived from rice (Oryza sativa) rice bran. A filler characterized by:

8. A fibrous material derived from biomass containing organic and inorganic substances is added to the base resin and kneaded in a high-temperature, high-pressure environment. The fibrous material is derived from rice (Oryza sativa) rice bran. A method for producing a resin composition comprising:

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