Composite resin composition containing plant filler and composite resin molded body using the same

Abstract

A composite resin composition containing a plant filler includes: a host resin; a plant filler dispersed in the host resin; and a dispersant dispersed in the host resin, 50% by mass or more and 97% by mass or less of the plant filler being a first plant filler containing less than 1% by mass of triacylglycerol, 3% by mass or more and 50% by mass or less of the plant filler being a second plant filler containing 1% by mass or more and 40% by mass or less of triacylglycerol, and the host resin being a crystalline resin.

Description

Technical Field

[0001] This invention relates to composite resin compositions containing plant fillers and molded articles using the composite resin compositions containing plant fillers. In particular, it relates to composite resin compositions containing plant fillers at high concentrations. Background Technology

[0002] Polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC), known as "general-purpose plastics," are relatively inexpensive, weigh only a fraction of that of metals or ceramics, and are easy to process, including molding. Therefore, general-purpose plastics are used as materials for bags, various packaging materials, containers, sheets, and many other everyday consumer goods. They are also used in automotive parts, electrical components, and other industrial parts, as well as in daily necessities and general merchandise.

[0003] However, general-purpose plastics have drawbacks such as insufficient mechanical strength. Therefore, the current situation is that general-purpose plastics do not possess the sufficient properties required for materials used in mechanical products such as automobiles, and various industrial products such as electrical, electronic, and information products, thus limiting their application scope.

[0004] On the other hand, so-called "engineering plastics" such as polyacetal (POM), polyamide (PA), polycarbonate (PC), and fluoropolymers have excellent mechanical properties and are used in various industrial products, including automobiles and other mechanical products, as well as electrical, electronic, and information products. However, engineering plastics have drawbacks such as high cost, difficulty in reusing monomers, and high environmental impact.

[0005] Therefore, there is an urgent need to significantly improve the material properties (mechanical strength, etc.) of general-purpose plastics. As a method for improving the material properties of general-purpose plastics, techniques for manufacturing composite resins by combining two or more resins or fillers are known. In particular, natural fibers, glass fibers, carbon fibers, etc., are used as fibrous fillers to improve mechanical strength. Among these, organic fibrous fillers such as cellulose have received considerable attention in recent years as reinforcing fibers due to their low cost and excellent environmental performance upon disposal.

[0006] One application of composite resins is in components such as appliance housings, automotive interior and exterior parts. Molding methods for manufacturing these components include injection molding and extrusion molding. These methods allow for high-cycle production, but require materials with high fluidity. However, while increasing the amount of filler increases the mechanical strength of the composite resin (e.g., elastic modulus), it also decreases its fluidity. Therefore, composite resins with high concentrations of filler exhibit reduced fluidity and are difficult to mold. Patent Document 1 describes how adding an ester-based plasticizer to a high-concentration filler composite resin improves fluidity and moldability.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-53758 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] One aspect of the present invention relates to a composite resin composition containing plant fillers comprising: a main resin; a plant filler dispersed in the main resin; and a dispersant dispersed in the main resin, wherein 50% to 97% by mass of the plant filler is a first plant filler containing less than 1% by mass of triacylglycerol, and 3% to 50% by mass of the plant filler is a second plant filler containing 1% to 40% by mass of triacylglycerol, and the main resin is a crystalline resin. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the composite resin composition containing plant filler according to Embodiment 1.

[0013] Figure 2 The graph shows the conditions and measurement results in Examples 1-4 and Comparative Examples 1-5. Detailed Implementation

[0014] The composite resin described in Patent Document 1 uses an ester-based plasticizer. However, compared to the main resin and filler, the strength of the plasticizer monomer is significantly lower, which leads to a decrease in the mechanical strength of the composite resin, such as its elastic modulus. In addition, since the plasticizer is a low-molecular-weight plasticizer, there is also the problem of seepage onto the surface of the granules and molded articles, that is, the plasticizer as an additive floats to the surface of the molded article.

[0015] The purpose of this invention is to provide a plant filler composite resin that has high fluidity and high mechanical strength without the addition of plasticizers.

[0016] The composite resin composition containing plant filler according to the first method comprises: a main resin; a plant filler dispersed in the main resin; and a dispersant dispersed in the main resin, wherein 50% to 97% by mass of the plant filler is a first plant filler containing less than 1% by mass of triglycerides, and 3% to 50% by mass of the plant filler is a second plant filler containing 1% to 40% by mass of triglycerides, and the main resin is a crystalline resin.

[0017] The second method involves a composite resin composition containing plant fillers that, based on the first method described above, has the following characteristics: when the total amount of the main resin, plant fillers, and dispersant in the composite resin composition containing plant fillers is set to 100% by mass, the content of plant fillers can be 50% by mass or more and 90% by mass or less.

[0018] The composite resin composition containing plant fillers involved in the third method is based on the first or second method described above, wherein the total amount of cellulose, hemicellulose, and lignin in the second plant filler can be more than 5% by mass and less than 50% by mass.

[0019] The fourth method involves a composite resin composition containing plant fillers in which, based on any of the methods 1 to 3 above, the total mass of cellulose, hemicellulose, and lignin in the first plant filler can be 80% or more.

[0020] The fifth method involves a composite resin composition containing plant fillers in which, based on any of the methods 1 to 4 above, the average particle size of the plant fillers can be 100 nm or more and 3 mm or less.

[0021] The composite resin composition containing plant fillers involved in Method 6 can have a crystallinity of 30% or more, based on any of Methods 1 to 5 above.

[0022] The composite resin composition containing plant filler involved in the seventh method is based on any of the methods 1 to 6 above, wherein the main agent resin may include a first region surrounding the plant filler and a second region away from the plant filler, and the crystallinity of the main agent resin in the first region is more than 1.05 times that of the main agent resin in the second region.

[0023] The composite resin molded article involved in the eighth method comprises a composite resin composition containing plant filler from any of the methods 1 to 7 above.

[0024] The present invention relates to a composite resin composition containing plant fillers, which contains 3% to 50% by mass of a second plant filler relative to the total amount of plant fillers, said second plant filler comprising 1% to 40% by mass of triglycerides. Additionally, it contains 50% to 97% by mass of a first plant filler, said first plant filler comprising less than 1% by mass of triglycerides. Therefore, it is possible to improve flowability while maintaining high strength, enabling application to high-recycle and high-volume molding methods such as injection molding and extrusion molding. Furthermore, since the main resin is a crystalline resin, the crystallinity around the plant filler and the overall crystallinity of the resin are increased, suppressing the exudation of triglycerides. Therefore, it can be used without problems as a molded article.

[0025] The following description, with reference to the accompanying drawings, describes the composite resin composition containing plant filler and its molded articles according to the embodiments. It should be noted that in the following description, the same symbols are used to denote the same components, and descriptions are omitted where appropriate.

[0026] (Implementation Method 1)

[0027] The composite resin composition 10 containing plant filler according to Embodiment 1 includes: a main resin 1; Figure 1 The first plant filler 2 is represented by a long, black rope-like structure; Figure 1 The second plant filler 3 is represented by an elliptical shape; Figure 1 Triglycerides 4, represented by a quadrilateral shape; and Figure 1 The dispersant 5 is represented by a triangular shape. The main resin 1 is a matrix comprising a non-crystalline portion 11 and a crystalline portion 12. The composite resin composition 10 containing plant filler is as follows... Figure 1 As shown, a first plant filler 2, a second plant filler 3, triglycerides 4, and a dispersant 5 are dispersed in the matrix of the main agent resin 1. Triglycerides 4 may be present on the surface and inside of the second plant filler 3, on the surface of the first plant filler 2, in the matrix of the main agent resin 1, etc., and dispersant 5 may be present at the interface between the first plant filler 2, the second plant filler 3, and the main agent resin 1, etc. In the first plant filler 2, 50% to 97% by mass of both the first plant filler 2 and the second plant filler 3 contain less than 1% by mass of triglycerides. In the second plant filler 3, 3% to 50% by mass of both the first plant filler 2 and the second plant filler 3 contain 1% to 40% by mass of triglycerides 4. Furthermore, the main agent resin 1 is a crystalline resin.

[0028] The composite resin composition 10 containing plant fillers according to Embodiment 1 contains 3% by mass and 50% by mass of the second plant filler 3 relative to the total amount of the first plant filler 2 and the second plant filler 3, wherein the second plant filler 3 contains 1% by mass and 40% by mass of triglycerides 4. Additionally, it contains 50% by mass and 97% by mass of the first plant filler 2, wherein the first plant filler 2 contains less than 1% by mass of triglycerides 4. Therefore, the composite resin composition 10 containing plant fillers has high strength and improved flowability, enabling its application in high-cycle and high-volume molding methods such as injection molding and extrusion molding. Furthermore, since the main resin 1 is a crystalline resin, the crystallinity around the first plant filler 2 and the second plant filler 3, as well as the overall crystallinity of the resin, is increased, which can suppress the exudation of triglycerides 4. Therefore, it can be used without problems as a molded article.

[0029] The components constituting the composite resin composition containing plant filler will be described below.

[0030] <Main Resin>

[0031] As the main resin 1 in the embodiment, a crystalline resin is preferred to suppress the exudation of triglycerides, and a thermoplastic resin is more preferred to ensure good formability. Examples of crystalline resins include olefin resins (including cyclic olefin resins), polyamide resins, polyphenylene ether resins (polymers of 2,6-xylenol, etc.), crystalline polyester resins, halogen-containing resins, and liquid crystal polymer resins. Two or more of the above resins can be used alone or in combination. It should be noted that the resin is not limited to the above materials as long as it is crystalline. Furthermore, when using two or more resins, at least one resin need to be crystalline.

[0032] Among these crystalline resins, the main resin is preferably an olefin resin with a low melting point. Olefin resins include not only homopolymers of olefin monomers, but also copolymers of olefin monomers and copolymers of olefin monomers with other comonomers. Examples of olefin monomers include chain olefins (such as α-C2-20 olefins like ethylene, propylene, 1-butene, isobutene, 1-pentene, 4-methyl-1-pentene, and 1-octene) and cyclic olefins. These olefin monomers can be used alone or in combination of two or more. Among the aforementioned olefin monomers, chain olefins such as ethylene and propylene are preferred. Specific examples of olefin resins include copolymers of chain olefins (especially α-C2-4 olefins) such as polyethylene (low-density, medium-density, high-density, or linear low-density polyethylene), polypropylene, ethylene-propylene copolymers, and terpolymers of ethylene-propylene-butene-1.

[0033] The main component resin 1 is preferably a crystalline resin. The crystalline portion 12 has a denser structure than the amorphous portion 11. Therefore, the diffusion rate of liquids, gases, etc., is significantly lower in the crystalline portion 12 compared to the amorphous portion 11. Triglycerides diffuse as a liquid component in the composite resin, and therefore, the diffusion rate in the crystalline portion 12 is significantly lower than that in the amorphous portion 11. By having the crystalline portion 12 in the resin, the diffusion rate of the liquid is reduced, thereby suppressing the exudation of triglycerides from the composite resin composition. Therefore, the main component resin 1 is preferably a crystalline resin.

[0034] The crystallinity of the main agent resin 1 is preferably 30% or more, more preferably 60% or more. When the crystallinity of the main agent resin 1 is less than 30%, the proportion of non-crystalline portion is large, and therefore it is almost impossible to suppress the exudation of triglycerides. Therefore, the crystallinity of the main agent resin 1 is preferably within the above-mentioned range.

[0035] The main resin 1 may comprise a first region surrounding the plant filler and a second region away from the plant filler. The crystallinity of the main resin 1 in the first region is preferably 1.05 times or more, more preferably 1.10 times or more, compared to the crystallinity of the main resin 1 in the second region. If the crystallinity of the main resin in the first region is too low, the resin surrounding the plant filler cannot form a dense structure. That is, triglycerides cannot be maintained around the plant filler, and exudation to the surface of the composite resin cannot be suppressed. Therefore, it is preferable that the crystallinity of the main resin 1 in the first region is within the aforementioned range compared to the crystallinity of the main resin 1 in the second region.

[0036] <First Plant Filler>

[0037] Examples of natural raw materials that can be used as the first plant filler 2 containing a certain amount of triacylglycerol in the embodiment include pulp, wood (coniferous and broadleaf trees), cotton linter, kenaf, Manila hemp (abaca), sisal, jute, Indian hay, papyrus, and bagasse. Alternatively, natural raw materials modified with acids or amines, or functional monomers containing epoxides, may also be used. The first plant filler 2 is preferably fibrous or granular, formed by pulverizing the aforementioned natural raw materials.

[0038] The combined amount of cellulose, hemicellulose, and lignin in the first plant filler 2, which contains less than 1% by mass of triacylglycerol, is preferably 80% by mass or more, more preferably 90% by mass or more. Cellulose, hemicellulose, and lignin are components that form the plant skeleton, and the strength of the plant largely depends on the amount of these three components. When the combined amount of cellulose, hemicellulose, and lignin in the first plant filler 2 is less than 80% by mass, the strength of the first plant filler decreases, and therefore the strength of the composite resin also decreases. Therefore, the combined amount of cellulose, hemicellulose, and lignin in the first plant filler 2 is preferably within the above-mentioned range.

[0039] <Second Plant Filler>

[0040] Examples of natural raw materials that can be used as the second plant filler 3 containing a certain amount or more of triglycerides in the embodiments include soybeans, wheat, barley, rice, and coffee beans. From environmental and cost perspectives, commercially discarded plant waste such as coffee bean residue after coffee extraction can also be used. The second plant filler 3 is preferably fibrous or granular, formed by pulverizing the aforementioned raw materials.

[0041] The triacylglycerol content of the second plant filler 3 is preferably 1% by mass or more and 40% by mass or less, more preferably 3% by mass or more and 30% by mass or less. When the triacylglycerol content is less than 1% by mass, the amount of triacylglycerol is too small, thus failing to improve the flowability of the composite resin composition. When the triacylglycerol content is greater than 40% by mass, the amount of triacylglycerol with low strength properties is excessive, thus reducing the strength properties of the plant filler and significantly decreasing the mechanical strength of the composite resin composition containing the plant filler. Therefore, the triacylglycerol content of the second plant filler 3 is preferably 1% by mass or more and 40% by mass or less, more preferably 3% by mass or more and 30% by mass or less.

[0042] Relative to the combined amount of the first plant filler 2 and the second plant filler 3, the second plant filler 3 is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 30% by mass or less. When the amount of the second plant filler 3 relative to the combined amount of the plant fillers is less than 3% by mass, the amount of triglycerides becomes too low, failing to adequately improve flowability. When it is greater than 50% by mass, since the amount of the second plant filler 3, which is weaker than the first plant filler 2, is large, the reinforcing effect of the plant fillers decreases, and the mechanical strength of the composite resin composition is reduced. Therefore, relative to the combined amount of the first plant filler 2 and the second plant filler 3, the second plant filler 3 is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 30% by mass or less.

[0043] The total amount of plant filler 2 and plant filler 3 in the composite resin composition is preferably 50% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 85% by mass or less. For example... Figure 1 As shown, the composite resin composition of this embodiment comprises a main resin 1, a first plant filler 2, a second plant filler 3, triacylglycerol 4, and a dispersant 5. The greater the amount of plant filler added, the greater the mechanical strength. Furthermore, the greater the proportion of plant-derived components, the greater the bioavailability, thus effectively reducing environmental impacts such as carbon neutrality. When the amount of plant filler is less than 50% by mass, the reinforcing effect of the resin from the plant filler decreases, and the mechanical strength of the composite resin decreases. Additionally, the bioavailability also decreases, thus reducing the environmental impact reduction effect. When the amount of plant filler is greater than 90% by mass, the amount of resin is too small, thus significantly reducing the fluidity of the composite resin, making stable mixing and molding impossible. Furthermore, because the amount of resin is too small compared to the amount of plant filler, the first plant filler 2 and the second plant filler 3 cannot be encapsulated within the main resin 1, resulting in a large amount of the first and second plant fillers exposed on the resin surface, making it impossible to suppress the exudation of triacylglycerol. Therefore, the amount of plant filler in the composite resin composition is preferably within the above-mentioned range.

[0044] The average particle size of the first and second plant fillers is preferably 100 nm or more and 3 mm or less. When the average particle size is less than 100 nm, the size of the first and second plant fillers is too small, resulting in an excessively large surface area for each filler. Consequently, the viscosity of the composite resin becomes too high, and the flowability is excessively reduced, making it impossible to add more than 50%. When the particle size is greater than 3 mm, it is impossible to uniformly disperse the plant fillers in the resin, leading to greater variations in strength within the composite resin composition and unstable quality. Therefore, the average particle size of the plant fillers is preferably within the aforementioned range.

[0045] <Triglycerides>

[0046] As in the embodiment, triacylglycerol 4 is preferably a component derived from natural raw materials or a component derived from natural raw materials that has deteriorated during the material manufacturing process. Examples of triacylglycerol include tripalmitoylglycerol and 1-linoleyl-2-palmitoyloleyl-3-stearoylglycerol. It should be noted that triacylglycerol is not limited to any component contained in the plant filler.

[0047] Triacylglycerol 4 is preferably derived from the aforementioned plant filler. Furthermore, when triacylglycerol is added, all the triacylglycerol is present in the resin from the initial stage of raw material mixing, resulting in lower viscosity, making it difficult to apply strong shear stress and hindering effective dispersion and defibrillation of the plant filler. Therefore, the triacylglycerol 4 of the present invention is preferably derived from the aforementioned plant filler.

[0048] The composite resin composition comprises the main resin 1, the first plant filler 2, the second plant filler 3, and the dispersant 5 in an amount of 100% by mass. Since triglyceride 4 is contained in the first plant filler 2 and the second plant filler 3, it is included in the amount of the first plant filler 2 and the second plant filler 3.

[0049] <Dispersant>

[0050] Examples of dispersants 5 in this embodiment include various titanate coupling agents, silane coupling agents, unsaturated carboxylic acids, maleic acid, maleic anhydride, or modified polyolefins grafted with their anhydrides, fatty acids, fatty acid metal salts, fatty acid esters, etc. Among these silane coupling agents, unsaturated hydrocarbon-based or epoxy-based silane coupling agents are preferred. It is also acceptable to treat and modify the surface of the dispersant with a thermosetting or thermoplastic polymer component. The dispersant 5 is appropriately selected based on the combination of the main resin 1, the first plant filler 2, and the second plant filler 3.

[0051] <Method for manufacturing composite resin composition>

[0052] In the method for manufacturing the composite resin composition according to Embodiment 1, the main resin, the first plant filler, the second plant filler and the dispersant are prepared in a predetermined mass ratio, and then the mixture is kneaded to obtain the composite resin composition.

[0053] As the mixing apparatus used in the manufacturing method of this composite resin composition, a kneader, a Banbury mixer, an extruder, or a roller mixer are preferred. Among these, a twin-screw mixer and a roller mixer are more preferred. It should be noted that the mixing apparatus is not limited to any apparatus having a rotating body as the mixing unit. Furthermore, since the components in the plant filler are easily decomposed by heat and are volatile, it is preferable to perform the mixing at a low temperature as much as possible.

[0054]

Example

[0055] exist Figure 2 The conditions and measurement results of Examples 1-4 and Comparative Examples 1-5 are shown in the figure.

[0056] The composite resin composition containing plant filler is manufactured by the following manufacturing method. As mentioned above, the mixing apparatus can be a kneader, a Banbury mixer, an extruder, a roller mixer, etc., but a twin-screw mixer is used in the examples.

[0057] Polypropylene (as the main resin), pulverized paper pulp and coffee grounds (as plant fillers), and maleic anhydride-modified polypropylene (as a dispersant) were weighed in a mass ratio of 27:60:10:3 and dry-mixed. It should be noted that softwood pulp (manufactured by Mitsubishi Paper Corporation, trade name: NBKP Celgar) was used as the starting material for the pulverized paper pulp. This softwood pulp was pulverized using a pulverizer to obtain fibrous fillers for the pulverized paper pulp. The filler size was adjusted during the pulverization process.

[0058] The mixture was melt-blended and dispersed using a twin-screw extruder (KRC kneader manufactured by Kurimoto Iron Works Co., Ltd.). By changing the screw configuration of the twin-screw extruder, the shear force could be altered; in Example 1, a low-shear type was used. The composite resin discharged from the twin-screw extruder was thermally cut to produce composite resin granules containing plant fillers.

[0059] Using the prepared composite resin granules containing plant fillers, test specimens of composite resin molded articles were fabricated using an injection molding machine (Nippon Steel 180AD). The dumbbell test specimens were fabricated under the following conditions: resin temperature 200°C, mold temperature 40°C, injection speed 60 mm / s, and holding pressure 100 MPa. The granules were fed into the screw of the molding machine via a hopper, and the invasiveness was measured by the amount of granules reduced per unit time, which was confirmed to be constant. The shape of the test specimens was modified according to the following evaluation items, and a size 1 dumbbell test specimen was fabricated for measuring the elastic modulus. Additionally, a spiral flow test specimen was fabricated for evaluating flowability. The obtained test specimens of composite resin molded articles containing plant fillers were evaluated using the following methods.

[0060] [Evaluation Items for Composite Resin Molded Articles]

[0061] (Elastic modulus of composite resin molded articles)

[0062] A three-point bending test was conducted using the obtained dumbbell-shaped test piece (No. 1). Here, as an evaluation method for the elastic modulus, values ​​less than 3.0 GPa were designated as D, values ​​above 3.0 GPa but less than 3.5 GPa as C, values ​​above 3.5 GPa but less than 5.0 GPa as B, and values ​​above 5.0 GPa as A. The elastic modulus of this test piece was 6.0 GPa, and its evaluation was A.

[0063] (Evaluation of the flowability of composite resins)

[0064] The length of the resulting spiral flow test piece was measured. Relative to the total length of the spiral flow, if the filled length is less than 30%, it is denoted as D; if it is 30% or more but less than 50%, it is denoted as C; if it is 50% or more but less than 70%, it is denoted as B; and if it is 70% or more, it is denoted as A. The length of this test piece was 63%, and its evaluation was B.

[0065] (Crystallization degree of composite resin)

[0066] The melting (crystallization) peak was measured using differential scanning calorimetry (DSC), and the heat of melting was calculated. The degree of crystallinity was then calculated using the following formula.

[0067] Crystallinity = (Heat of fusion measured / Heat of fusion of fully crystallized material) × 100

[0068] Here, as a method for evaluating crystallinity, cases with less than 30% are denoted as D, cases with more than 30% but less than 60% are denoted as B, and cases with more than 60% are denoted as A. This composite resin has a crystallinity of 61%, and its evaluation is A.

[0069] (Crystallinity around the fiber)

[0070] A portion was cut from the obtained dumbbell-shaped test piece (No. 1) and subjected to Raman spectroscopy. Cases where the crystallinity of the resin surrounding the plant filler was less than 1.05 times that of the crystallized portion were categorized as D, and cases where it was more than 1.05 times were categorized as B. The crystallinity of this test piece was 1.13 times, and its evaluation was B.

[0071] (Evaluation results of triglyceride exudation)

[0072] Triglyceride exudation evaluation tests were conducted using the obtained dumbbell-shaped test piece (No. 1). Normally, the test piece was placed at room temperature. For accelerated testing, it was placed in a small hot air dryer at 60°C, and the surface of the test piece was checked for stickiness every 24 hours. For sticky test pieces, the surface was placed in a solvent capable of dissolving triglycerides, and solvent composition analysis was performed to confirm whether the exuded component was triglycerides. The test in a 60°C hot air environment was approximately 50 times faster than the test in a normal atmosphere at room temperature. Exudation within 48 hours was recorded as D, exudation between 48 and 72 hours as C, exudation between 72 and 96 hours as B, and exudation beyond 96 hours as A. The evaluation of this test piece was B.

[0073] (Example 2)

[0074] In Example 2, the amount of plant filler was reduced, and the mass ratio of main resin: pulverized pulp: coffee grounds: dispersant was changed to 43:45:10:2. All other conditions were the same as in Example 1 to prepare composite resin granules and molded articles containing plant fibers. The same evaluation was performed as in Example 1.

[0075] (Example 3)

[0076] In Example 3, pulverized pulp with an average particle size 2 mm larger than that in Example 1 was used as the plant fiber. All other material and process conditions were the same as in Example 1 to prepare the composite resin granules and molded articles containing cellulose fibers. The same evaluation was performed as in Example 1.

[0077] (Example 4)

[0078] In Example 4, compared to Example 1, the injection molding condition was changed to a high-temperature mold temperature. Regarding other material and process conditions, the composite resin granules and molded articles containing cellulose fibers were prepared in the same manner as in Example 1. The same evaluation as in Example 1 was also performed.

[0079] (Comparative Example 1)

[0080] In Comparative Example 1, only coffee grounds were used as plant filler, and the mass ratio of main resin: pulp: coffee grounds: dispersant was changed to 27:0:70:3. All other material and process conditions were the same as in Example 1 for preparing composite resin granules and molded articles. The same evaluation as in Example 1 was also performed.

[0081] (Comparative Example 2)

[0082] In Comparative Example 2, only pulp was used as the plant filler, and the mass ratio of main resin: pulp: coffee grounds: dispersant was changed to 27:70:0:3. All other material and process conditions were the same as in Example 1 to prepare the composite resin granules and molded articles. The same evaluation as in Example 1 was also performed.

[0083] (Comparative Example 3)

[0084] In Comparative Example 3, PS, a non-crystalline resin, was used as the main resin. All other material and process conditions were the same as in Example 1 to prepare composite resin granules and molded articles containing cellulose fibers. The same evaluation as in Example 1 was also conducted.

[0085] (Comparative Example 4)

[0086] In Comparative Example 4, the amount of plant fiber was reduced compared to Example 1, and the mass ratio of main resin: pulp: coffee grounds: dispersant was changed to 79:15:5:1. Apart from this, the composite resin granules and molded articles containing plant fibers were prepared in the same manner as in Example 1, using the same material and process conditions. The same evaluation as in Example 1 was also conducted.

[0087] (Comparative Example 5)

[0088] In Comparative Example 5, the amount of plant filler was increased compared to Example 1, and the weight ratio of main resin: pulp: coffee grounds: dispersant was changed to 2.5:70:25:2.5. Apart from this, the composite resin granules and molded articles containing plant filler were prepared in the same manner as in Example 1, with respect to all other material and process conditions. The same evaluation as in Example 1 was also conducted.

[0089] The measurement results of each of Examples 1 to 4 and each of Comparative Examples 1 to 5 are shown in the table in Figure 3.

[0090] In Example 2, with a reduced amount of plant filler, the reinforcing effect of the plant filler was less compared to Example 1, resulting in an elastic modulus of 5.3 GPa. Crystallinity decreased to 56% due to the reduced amount of plant filler.

[0091] In Example 3, which used pulverized pulp with an average particle size of 2 mm, the particle size was larger and the surface area was reduced compared to Example 1, resulting in a reduced reinforcing effect and an elastic modulus of 3.7. Its evaluation result was B.

[0092] In Example 4, where the mold temperature during injection molding was set to a high temperature, the composite resin was cooled slowly compared to Example 1, resulting in increased crystallinity of 66%, which was rated as A.

[0093] In Comparative Example 1, which uses only coffee grounds as plant filler, the plant filler has a small reinforcing effect on the resin, with an elastic modulus of 2.4 GPa, and the evaluation result is D.

[0094] In Comparative Example 2, which uses only pulp as plant filler, the fluidity is lower, and the fluidity evaluation result is D.

[0095] In Comparative Example 3, which uses PS as the main resin and is a non-crystalline resin, the exudation of triglycerides could not be suppressed because there were no crystalline components in the resin, and the exudation evaluation result was D.

[0096] In Comparative Example 4, where the weight ratio of plant fiber was reduced relative to all raw materials, the reinforcing effect of the filler on the composite resin was smaller due to the smaller amount of plant filler, and the elastic modulus was 1.9 GPa.

[0097] In Comparative Example 5, where the weight ratio of plant fiber was increased relative to all raw materials, the amount of plant filler was too high and the amount of resin was too low. As a result, the viscosity of the composite resin became too high, increasing the load on the equipment and making it impossible to stably mix and mold. Therefore, it was impossible to produce test pieces and conduct evaluation.

[0098] Based on the above evaluation, it is evident that when only a second plant filler containing 1% to 40% by mass of triglycerides is used, the strength of the composite resin does not reach the necessary level. On the other hand, when only a first plant filler containing less than 1% by mass of triglycerides is used, the flowability decreases, making it impossible to stably form complex shapes such as finished products. Furthermore, when using a non-crystalline resin as the main resin, the exudation of triglycerides cannot be suppressed. Moreover, reducing the concentration of plant filler results in a smaller amount of plant filler, thus reducing the reinforcing effect and lowering the strength of the composite resin. Conversely, excessively increasing the concentration of plant filler makes stable mixing and molding impossible. Therefore, by using a plant filler containing triglycerides and a crystalline resin, with a plant filler content of 50% to 90% by mass, a composite resin composition with high mechanical strength and improved flowability can be stably produced.

[0099] It should be noted that, in this invention, any appropriate combination of the various embodiments and / or examples described above can achieve the effects of each embodiment and / or example.

[0100] Industrial availability

[0101] According to one aspect of the present invention, a composite resin composition can provide molded articles with superior mechanical strength compared to conventional general-purpose resins, high biocompatibility (with a plant filler content of 50% by mass or more), and environmental friendliness. Because the composite resin composition of one aspect of the present invention does not require the addition of additional plasticizers, it exhibits high fluidity, thus enabling the production of molded articles through highly recyclable and mass-production molding methods such as injection molding and extrusion molding. Therefore, the composite resin molded articles of one aspect of the present invention can be used in applications requiring excellent mechanical strength and high productivity, such as appliance housings, building materials, and automotive components.

[0102] Explanation of reference numerals in the attached figures

[0103] 1. Main agent resin

[0104] 2. First plant filler

[0105] 3. Second plant filler

[0106] 4. Triglycerides

[0107] 5. Dispersant

[0108] 10 Composite resin compositions containing plant fillers

[0109] 11. Non-crystalline portion

[0110] 12 Crystallized Parts

Claims

1. A composite resin composition containing plant filler, comprising: Main component resin; Plant filler, dispersed in the main resin; and Dispersant, which is dispersed in the main resin, The plant filler comprises 50% to 97% by mass of a first plant filler containing less than 1% by mass of triglycerides. The plant filler comprises 3% to 50% by mass of a second plant filler containing 1% to 40% by mass of triglycerides. The main resin is a crystalline resin. wherein When the total amount of the main resin, the plant filler, and the dispersant in the composite resin composition containing plant filler is set to 100% by mass, the content of the plant filler is 50% by mass or more and 90% by mass or less.

2. The composite resin composition containing plant filler according to claim 1, wherein, The combined amount of cellulose, hemicellulose, and lignin in the second plant filler is more than 5% by mass and less than 50% by mass.

3. The composite resin composition containing plant filler according to claim 1 or 2, wherein, The total mass of cellulose, hemicellulose, and lignin in the first plant filler is 80% or more.

4. The composite resin composition containing plant filler according to claim 1 or 2, wherein, The average particle size of the plant filler is above 100 nm and below 3 mm.

5. The composite resin composition containing plant filler according to claim 1 or 2, wherein, The crystallinity of the main resin is above 30%.

6. The composite resin composition containing plant filler according to claim 1 or 2, wherein, The main resin comprises a first region surrounding the plant filler and a second region away from the plant filler, wherein the crystallinity of the main resin in the first region is more than 1.05 times that of the main resin in the second region.

7. A composite resin molded article comprising the composite resin composition containing plant filler as described in any one of claims 1 to 6.

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