Resin composition, resin molding and method for producing resin pellet

Abstract

To provide a resin composition, a resin molding and a method for producing a resin pellet, in which the corrosion of a mold during injection molding is suppressed and the generation of an isocyanate gas is suppressed.SOLUTION: There is provided a method for producing a resin composition 30 which comprises a step of kneading a plant fiber 10, a polyolefin-based resin 11 and at least one of a first cyclic compound, a second cyclic compound, a third cyclic compound and a fourth cyclic compound to obtain a resin composition 30, wherein for example, the first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide in which a first nitrogen and a second nitrogen are bonded by a bonding group and two or more first subcyclic structures fused to a part of the main cyclic structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin composition containing plant fibers and a polyolefin resin, a resin molded product, and a method for producing resin pellets. [Background technology]

[0002] Conventionally, in order to ensure the strength of a resin composition, a method has been adopted in which vegetable fibers or inorganic materials such as calcium carbonate, talc, or glass fibers are blended as a filler with a base synthetic resin (polyolefin resin). In particular, vegetable fibers have a lower specific gravity than inorganic materials, and are therefore used as a filler as a method for improving the strength of a resin composition while reducing its weight.

[0003] However, when the temperature of the plant fibers, which are made of components such as lignin and hemicellulose, rises to a high temperature (about 200° C.), the lignin and hemicellulose undergo thermal decomposition to generate corrosive gases such as carboxylic acids. Therefore, when a resin composition containing plant fibers and a synthetic resin is injection molded at high temperatures, there is a risk of corroding a mold used for injection molding.

[0004] For example, Patent Document 1 discloses a method for producing a resin composition for molding material that contains plant fibers, a thermoplastic resin, and a compound reactive with a carboxy group. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6986655 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the molecular weight of the carboxylic acid is small and the compound that reacts with the carboxylic acid is a chain carbodiimide, there is a problem in that isocyanate gas is generated.

[0007] The present invention has been made in consideration of the above points, and aims to provide a resin composition, a resin molded product, and a method for producing resin pellets that suppress corrosion of a mold during injection molding and prevent the generation of isocyanate gas. [Means for solving the problem]

[0008] The method for producing the resin composition of the present invention comprises the steps of: Plant fibres and A polyolefin resin, and at least one of a first cyclic compound, a second cyclic compound, a third cyclic compound, and a fourth cyclic compound, to obtain a resin composition, the first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide in which a first nitrogen and a second nitrogen are bonded by a bonding group, and two or more first subcyclic structures condensed to a part of the main cyclic structure; the second cyclic compound is a cyclic compound having the main cyclic structure and two or more second subcyclic structures extending from the main cyclic structure as substituents, the third cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure fused to a portion of the main cyclic structure, and a second subcyclic structure extending as a substituent from each of the first subcyclic structures; The fourth cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure fused to a portion of the main cyclic structure, and a second subcyclic structure fused to a portion of the first subcyclic structure. [Brief description of the drawings]

[0009] [Figure 1] 1A to 1C are diagrams illustrating a process for producing a resin composition and a resin molded article according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing a reaction process between a corrosive gas and a cyclic compound. [Diagram 3] 5A to 5C are diagrams illustrating a process for producing a resin composition and a resin molded body according to Modification 1 of the first embodiment of the present invention. [Figure 4] 6A to 6C are diagrams illustrating a manufacturing process of a resin pellet according to Modification 2 of the first embodiment of the present invention. [Diagram 5] 5A to 5C are diagrams illustrating a process for producing a resin composition and a resin molded article according to a second embodiment of the present invention. [Figure 6] 1 is a table summarizing the results of comparison between examples and comparative examples of the resin composition of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] A first embodiment of the present invention will be described. As shown in FIG. 1, in the method for producing a resin composition of the first embodiment, a plant fiber 10, a polyolefin resin 11, and a cyclic compound 20 having a carbodiimide group are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200 degrees, for example, to obtain a resin composition 30. Next, the resin composition 30 is injected into a molding machine 41 and injection molded at a high temperature to obtain a resin molded body 31. The screw rotation speed and cylinder temperature of the twin-screw mixer can be appropriately changed. In addition, the device used for kneading is not limited to the twin-screw mixer.

[0011] The plant fiber 10 refers to a natural fiber obtained from a plant, and its main components are cellulose, hemicellulose, and lignin, which are structural components of the plant cell wall. As shown in Fig. 2, hemicellulose and lignin are thermally decomposed at high temperatures (about 200°C) to generate carboxylic acid, which is a corrosive gas 10A.

[0012] The carboxylic acid generated from the plant fiber 10 reacts with the cyclic compound 20. In other words, the carboxylic acid is masked by the cyclic compound 20. This makes it possible to suppress the reaction of the carboxylic acid with a mold (e.g., iron) used in injection molding, which would otherwise corrode the mold. The reaction mechanism between the carboxylic acid and the cyclic compound 20 is shown below. [ka]

[0013] In addition, the use of the cyclic compound 20 can prevent the generation of isocyanate gas due to the above-mentioned reaction mechanism. In other words, by kneading the plant fibers 10 and the polyolefin resin 11 with the cyclic compound 20 contained therein, it is possible to prevent the generation of isocyanate gas while suppressing corrosion of the mold caused by carboxylic acid generated from the plant fibers 10.

[0014] It should be noted that isocyanate gas is generated, for example, when the molecular weight of the carboxylic acid generated from the plant fiber is small and the compound that reacts with the carboxylic acid is a chain carbodiimide.

[0015] In addition, by using the cyclic compound 20, the above-mentioned reaction mechanism is followed, so that fogging caused by isocyanate gas from the resin composition can be prevented. Here, fogging caused by isocyanate gas refers to the volatilization of isocyanate gas from the resin composition due to the increase in temperature of the resin composition.

[0016] Examples of the plant fiber 10 used in the resin composition of the present invention include wood flour, wood fibers such as paper, cellulose fibers, cellulose nanofibers, biomass materials derived from plants, cellulose extracted from plants or separately synthesized, hemicellulose, lignin, etc. Examples of the wood flour that can be used include wood flour derived from conifers, broad-leaved trees, rice straw, rice husks, wheat straw, bamboo, pine, cedar, cypress, kenaf, pulp, sisal hemp, Manila hemp, jute hemp, coconut, corn, reed, palm, and papyrus.

[0017] It is preferable to use wood flour derived from coniferous trees as the plant fibers 10. When comparing coniferous trees and broad-leaved trees, the amount of cellulose is the same, but coniferous trees have a larger amount of lignin and a smaller amount of hemicellulose than broad-leaved trees. The thermal decomposition temperature of hemicellulose is 180 to 300°C, and the thermal decomposition temperature of lignin is 280 to 550°C. Therefore, coniferous trees, which have a relatively smaller amount of hemicellulose and a larger amount of lignin, have high heat resistance. Therefore, by using wood flour derived from coniferous trees as the plant fibers 10, the heat resistance of the resin composition 30 can be improved.

[0018] The blending amount of the plant fiber 10 is preferably 10% by weight (wt%) to 85% by weight, more preferably 30% by weight to 70% by weight, based on the total amount of the resin composition 30. When the blending amount of the plant fiber is low, it is difficult to ensure sufficient strength, so the blending amount of the plant fiber is preferably 10% by weight or more, more preferably 30% by weight or more. In addition, the strength increases as the blending amount of the plant fiber increases, but on the other hand, the fluidity of the resin composition decreases, making it difficult to knead sufficiently, so the blending amount of the plant fiber is preferably 85% by weight or less, more preferably 70% by weight or less. In addition, it is difficult to ensure sufficient moldability due to the decrease in the fluidity of the resin composition.

[0019] The polyolefin resin 11 may be polypropylene (PP), polyethylene (PE), or the like.

[0020] The blending amount of the polyolefin resin 11 is preferably 15% by weight to 90% by weight, and more preferably 30% by weight to 70% by weight, based on the total amount of the resin composition 30. When the blending amount of the polyolefin resin is low, the fluidity of the resin composition decreases and it becomes difficult to knead it sufficiently, so the blending amount of the polyolefin resin is preferably 15% by weight or more, and more preferably 30% by weight or more. When the blending amount of the polyolefin resin is high, it becomes difficult to ensure sufficient strength, so the blending amount of the polyolefin resin is preferably 90% by weight or less, and more preferably 70% by weight or less. In addition, since the polyolefin resin is made from fossil fuels such as petroleum, reducing the blending amount of the polyolefin resin is also useful from the viewpoint of environmental resource conservation.

[0021] The cyclic compound 20 is any one of the following first, second, third and fourth cyclic compounds.

[0022] The first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide to which the first nitrogen and the second nitrogen are bonded by a bonding group, and two or more first subcyclic structures condensed to a part of the main cyclic structure. The main cyclic structure refers to a structure with the minimum number of bonds to form a cyclic carbodiimide. The first cyclic compound may have a plurality of main cyclic structures. The bonding group refers to a carbon atom constituting a carbodiimide group. The first nitrogen and the second nitrogen refer to the nitrogen atom bonded to the carbon atom that is the bonding group, respectively.

[0023] As the first cyclic compound, for example, the following compounds (1) to (26) can be used. In addition, it is preferable to use the following compound (1) as the first cyclic compound because of ease of synthesis and inexpensive raw materials. [ka] [ka] [ka]

[0024] The second cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide to which the first and second nitrogens are bonded by a bonding group, and two or more second subcyclic structures extending from the main cyclic structure as substituents. The main cyclic structure refers to a structure with the minimum number of bonds forming a cyclic carbodiimide. The bonding group refers to a carbon atom constituting a carbodiimide group. The first nitrogen and the second nitrogen refer to the nitrogen atom bonded to the carbon atom that is the bonding group, respectively.

[0025] As the second cyclic compound, for example, the following compounds (27) to (30) can be used. [ka]

[0026] The third cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide to which the first and second nitrogens are bonded by a bonding group, a first subcyclic structure condensed to a part of the main cyclic structure, and a second subcyclic structure extending from the first subcyclic structure as a substituent. The main cyclic structure refers to a structure with the minimum number of bonds that form a cyclic carbodiimide. The bonding group refers to a carbon atom that constitutes a carbodiimide group. The first nitrogen and the second nitrogen refer to the carbon atom that is the bonding group and the nitrogen atom bonded to each other.

[0027] As the third cyclic compound, for example, the following compounds (31) to (32) can be used. [ka]

[0028] The fourth cyclic compound is a cyclic compound having a main cyclic structure including a carbodiimide in which the first and second nitrogens are bonded by a linking group, a first subcyclic structure fused to a portion of the main cyclic structure, and a second subcyclic structure fused to a portion of the first subcyclic structure.

[0029] As the quaternary cyclic compound, for example, the following compounds (33) to (35) can be used. [ka]

[0030] The fourth cyclic compound may be a cyclic compound having a main cyclic structure containing a carbodiimide in which the first nitrogen and the second nitrogen are bonded via a bonding group, a first subcyclic structure fused to a part of the main cyclic structure, a second subcyclic structure fused to a part of the first subcyclic structure, and a third subcyclic structure fused to a part of the second subcyclic structure, as shown in compound (36) below. [ka]

[0031] The amount of the cyclic compound 20 is preferably 0.05% by weight to 5.00% by weight with respect to the plant fiber 10. If the amount of the cyclic compound is less than 0.05% by weight, the amount of the cyclic compound is insufficient relative to the corrosive gas 10A, and most of the corrosive gas 10A remains unreacted. As a result, the corrosion of the mold used during molding is not sufficiently suppressed.

[0032] It is preferable to set the blending amount of the cyclic compound 20 to 0.5% by weight or more and to use wood flour derived from coniferous trees as the plant fibers 10. By setting the blending amount of the cyclic compound 20 to 0.5% by weight or more and using wood flour derived from coniferous trees as the plant fibers 10, it is possible to further improve corrosion resistance.

[0033] The use of the resin molded body 31 made from the resin composition 30 of the present invention is not particularly limited, and it can be used for automobile exterior and interior parts, lighting equipment, imaging equipment such as cameras and sensors, fixtures, daily necessities such as stationery, etc. In particular, the resin molded body 31 made from the resin composition 30 of the present invention is useful for use as a component of equipment having a heat source with a temperature of 300° C. or less, such as a housing or bracket of a vehicle lamp, because it prevents fogging caused by isocyanate gas at high temperatures.

[0034] The first embodiment will be described in more detail below with reference to modified examples, although the present invention is not limited to these modified examples. [Modification 1 of the first embodiment] A first modified example of the method for producing a resin composition according to the first embodiment will be described. As shown in Fig. 3, in the first modified example of the method for producing a resin composition according to the present embodiment, a polyolefin resin 12 containing plant fibers and a cyclic compound 20 are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200°C to obtain a resin composition 30. The resin composition 30 is injected into a molding machine 41 and undergoes a molding process in which the resin composition is injection-molded at high temperature to become a resin molded body 31.

[0035] [Modification 2 of the First Embodiment] A second modified example of the method for producing a resin composition according to the first embodiment will be described. As shown in Fig. 4, in the second modified example of the method for producing a resin composition according to the present embodiment, a polyolefin resin 12 containing plant fibers and a cyclic compound 20 are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200°C to obtain a pellet-shaped resin pellet 32. [Second embodiment]

[0036] A second embodiment of the present invention will be described below, in which explanations of the same components as those in the method for producing a resin composition according to the first embodiment of the present invention will be omitted where appropriate.

[0037] As shown in FIG. 5, in the method for producing a resin composition of the second embodiment, a plant fiber 10, a polyolefin resin 11, a cyclic compound 20, and a polyamine 50 having at least one of a primary amine and a secondary amine are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200 degrees to obtain a resin composition 30. The resin composition 30 is injected into a molding machine 41 and injection molded at a high temperature to obtain a resin molded body 31. That is, the method for producing a resin composition of the second embodiment is different from the first embodiment in that a polyamine is contained. Note that a polyoxazoline may be contained instead of a polyamine, or a polyamine and a polyoxazoline may be contained.

[0038] Polyamine or polyoxazoline reacts with carboxylic acid and aldehyde, which are corrosive gases 10A generated when the plant fiber 10 is thermally decomposed. Therefore, by including polyamine or polyoxazoline, corrosion of the mold can be further suppressed.

[0039] For example, carboxylic acids can react with primary and / or secondary amines to give carboxylic acid amides. As an example, the reaction mechanism of a carboxylic acid with a primary amine is shown below. [ka]

[0040] For example, aldehydes react with primary amines and / or secondary amines to form imines. As an example, the reaction mechanism of an aldehyde and a primary amine is shown below. [ka]

[0041] Corrosive gas 10A generated from hemicellulose or lignin contains a large proportion of long-chain fatty acids. The long-chain fatty acids reacted with polyamine or polyoxazoline are oriented in the flow direction due to the flow during injection molding. Since most of the long-chain fatty acids are hydrophobic hydrocarbon groups, the resin composition exerts a wax effect on its surface layer, resulting in high releasability from hydrophobic molds.

[0042] As the polyamine 50, aliphatic amines such as polyallylamine, polyethyleneimine, polyvinylamine, polypropyleneimine, polybutyleneimine, and polyisopropyleneimine, as well as aromatic amines having an alkyl group such as p-hexylaniline and 2-hexyl-5-aminothiophene can be used. If the boiling point of the polyamine is low, there is a concern that it will evaporate when kneaded with the plant fiber 10 and the polyolefin resin 11. Therefore, it is preferable to use an aliphatic amine or aromatic amine with a boiling point or decomposition temperature of 250° C. or higher.

[0043] The weight average molecular weight (Mw) of the polyamine 50 and the polyoxazoline is preferably 300 to 100,000, more preferably 10,000 to 100,000, and further preferably 10,000 to 70,000. If the weight average molecular weight of the polyamine and the polyoxazoline is smaller than 300, the polyamine will volatilize due to heat during kneading with the plant fiber 10 and the polyolefin resin 11. Therefore, the wax effect on the surface of the resin composition will not be expressed, and the mold releasability will decrease. In addition, if the weight average molecular weight is small, the toxicity of the polyamine is high, so care must be taken when handling it. Therefore, the workability during production will decrease. If the weight average molecular weight of the polyamine and the polyoxazoline is larger than 100,000, the viscosity of the resin composition will increase, making it difficult to knead it sufficiently. Therefore, the reaction between the primary amine and / or the secondary amine and the corrosive gas will be insufficient, and much of the corrosive gas will remain unreacted. Therefore, the corrosion of the mold used during injection molding is not sufficiently suppressed. Also, when the weight average molecular weight of the polyamine and polyoxazoline is greater than 100,000, the ratio of tertiary amine per unit mass is large, and the ratio of primary amine and / or secondary amine that reacts with the corrosive gas 10A is small. Therefore, the corrosion of the mold used during injection molding is not sufficiently suppressed.

[0044] The amount of polyamine 50 or polyoxazoline is preferably 0.05% by weight to 3.00% by weight with respect to the plant fiber 10. By making the amount of polyamine or polyoxazoline 0.05% by weight or more, the inhibition of mold corrosion can be further improved. In addition, if the amount of polyamine or polyoxazoline is higher than 3.00% by weight, the amount of polyamine may be excessive with respect to the corrosive gas 10A generated from the plant fiber 10. The excess polyamine or polyoxazoline reacts with the hydrophobic component of the resin composition that exhibits releasability from a hydrophobic mold, thereby reducing the releasability of the resin composition from the mold.

[0045] The second embodiment will be described in more detail below with reference to modified examples, although the present invention is not limited to these modified examples. [Modification 1 of the second embodiment] A first modified example of the method for producing a resin composition according to the second embodiment will be described. In the first modified example of the method for producing a resin composition according to the present embodiment, a polyolefin resin 12 containing plant fibers, a cyclic compound 20, and a polyamine 50 having at least one of a primary amine and a secondary amine are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200° C. to obtain a resin composition 30. The resin composition 30 is injected into a molding machine 41 and injection molded at a high temperature to obtain a resin molded body 31.

[0046] [Modification 2 of the second embodiment] A second modified example of the method for producing a resin composition according to the second embodiment will be described. In the second modified example of the method for producing a resin composition according to the present embodiment, a polyolefin resin 12 containing plant fibers, a cyclic compound 20, and a polyamine 50 having at least one of a primary amine and a secondary amine are kneaded in a twin-screw mixer 40 at a screw rotation speed of 250 rpm and a cylinder temperature of 200° C. to obtain resin pellets 32. EXAMPLES

[0047] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0048] Example 1 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the following cyclic compound B-1 was used in an amount of 0.10% relative to the wood flour. [ka]

[0049] These materials were kneaded in a biaxial kneading machine (Technovel Co., Ltd., KZW25TW-60MG-NH(-600)) at, for example, a screw rotation speed of 250 rpm and a cylinder temperature of 200 ° C. to obtain a resin composition. Next, the obtained resin composition was dried for 2 hours in a hot air dryer at 100 ° C. Next, the dried resin composition was injection molded in an injection molding machine (Japan Steel Works, Ltd., J100ADS-100U) equipped with an ISO physical property test piece mold, with the conditions set to a cylinder temperature of 300 ° C., a mold temperature of 80 ° C., an injection pressure of 50 MPa (gauge pressure), an injection speed of 200 mm / sec, and an injection time / cooling time = 20 sec / 20 sec, to obtain a rectangular test piece (resin molded body) of Example 1 having a length of 80.0 mm, a width of 10.0 mm, and a thickness of 4.0 mm.

[0050] Example 2 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 5.00% relative to the wood flour. Using these materials, a rectangular test piece for Example 2 was obtained by the same method as in Example 1.

[0051] Example 3 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the following cyclic compound B-2 was used in an amount of 0.10% relative to the wood flour. Using these materials, a rectangular test piece of Example 3 was obtained by the same method as Example 1. [ka]

[0052] Example 4 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-2 as in Example 3 was used in an amount of 5.00% relative to the wood flour. Using these materials, a rectangular test piece for Example 4 was obtained by the same method as in Example 1.

[0053] Example 5 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the following cyclic compound B-3 was used in an amount of 0.10% relative to the wood flour. Using these materials, a rectangular test piece of Example 5 was obtained by the same method as Example 1. [ka]

[0054] Example 6 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-3 as in Example 5 was used in an amount of 5.00% relative to the wood flour. Using these materials, a rectangular test piece for Example 6 was obtained by the same method as in Example 1.

[0055] Example 7 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the following cyclic compound B-4 was used in an amount of 0.10% relative to the wood flour. Using these materials, a rectangular test piece of Example 7 was obtained by the same method as in Example 1. [ka]

[0056] Example 8 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-4 as in Example 7 was used in an amount of 5.00% relative to the wood flour. Using these materials, a rectangular test piece for Example 8 was obtained by the same method as in Example 1.

[0057] Example 9 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 9 was obtained by the same method as in Example 1.

[0058] Example 10 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 10 was obtained by the same method as in Example 1.

[0059] Example 11 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 11 was obtained by the same method as in Example 1.

[0060] Example 12 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a rectangular test piece of Example 12 was obtained by the same method as in Example 1.

[0061] Example 13 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-2 (product name: Epomin R, product number: P-1000, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 13 was obtained by the same method as in Example 1.

[0062] Example 14 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-2 (product name: Epomin R, product number: P-1000, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a rectangular test piece of Example 14 was obtained by the same method as in Example 1.

[0063] Example 15 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-2 (product name: Epomin R, product number: P-1000, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 13 was obtained by the same method as in Example 1.

[0064] Example 16 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-2 (product name: Epomin R, product number: P-1000, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 16 was obtained by the same method as in Example 1.

[0065] Example 17 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.05% of the wood flour was used. As a polyoxazoline, a polyoxazoline C-3 (product name: EPOCROSS R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.50% of the wood flour was used. Using these materials, a rectangular test piece of Example 17 was obtained by the same method as in Example 1.

[0066] Example 18 As the polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As the carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.05% of the wood flour was used. As the polyoxazoline, polyoxazoline C-3 (product name: EPOCROSS R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 3.00% of the wood flour was used. Using these materials, a rectangular test piece of Example 18 was obtained by the same method as in Example 1.

[0067] Example 19 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-3 (product name: EPOCROSS R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a rectangular test piece of Example 19 was obtained by the same method as in Example 1.

[0068] Example 20 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-3 (product name: EPOCROSS R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) having a weight average molecular weight of 40,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 20 was obtained by the same method as in Example 1.

[0069] Example 21 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-4 (product name: EPOCROSS R, product number: WS-500, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 0.50% relative to the wood flour. Using these materials, a rectangular test piece of Example 21 was obtained by the same method as in Example 1.

[0070] Example 22 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-4 (product name: EPOCROSS R, product number: WS-500, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a rectangular test piece of Example 22 was obtained by the same method as in Example 1.

[0071] Example 23 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-4 (product name: EPOCROSS R, product number: WS-500, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 70,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a rectangular test piece of Example 23 was obtained by the same method as in Example 1.

[0072] Example 24 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyoxazoline, a polyoxazoline C-4 (product name: EPOCROSS R, product number: WS-500, manufactured by Nippon Shokubai Co., Ltd.) having a weight average molecular weight of 70,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 24 was obtained by the same method as in Example 1.

[0073] Example 25 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 25 was obtained by the same method as in Example 1.

[0074] Example 26 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 0.05% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 26 was obtained by the same method as in Example 1.

[0075] Example 27 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 0.05% relative to the wood flour. Using these materials, a rectangular test piece of Example 27 was obtained by the same method as in Example 1.

[0076] Example 28 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 3.00% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 3.00% relative to the wood flour. Using these materials, a rectangular test piece of Example 28 was obtained by the same method as in Example 1.

[0077] Example 29 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.50% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.50% of the wood flour was used. Using these materials, a rectangular test piece of Example 29 was obtained by the same method as in Example 1.

[0078] Example 30 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.50% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 1.50% of the wood flour was used. Using these materials, a rectangular test piece of Example 30 was obtained by the same method as in Example 1.

[0079] Example 31 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 1.50% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 0.50% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 31 was obtained by the same method as in Example 1.

[0080] Example 32 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used in an amount of 1.50% relative to the wood flour. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used in an amount of 1.50% relative to the wood flour. Using these materials, a strip-shaped test piece of Example 32 was obtained by the same method as in Example 1.

[0081] Example 33 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.05% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.025% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.025% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 33 was obtained by the same method as in Example 1.

[0082] Example 34 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.05% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 1.50% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 1.50% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 34 was obtained by the same method as in Example 1.

[0083] Example 35 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 3.00% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.025% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.025% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 35 was obtained by the same method as in Example 1.

[0084] Example 36 As the polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As the carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 3.00% of the wood flour was used. As the polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 1.50% of the wood flour was used. As the polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 1.50% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 36 was obtained by the same method as in Example 1.

[0085] Example 37 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.50% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.025% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.025% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 37 was obtained by the same method as in Example 1.

[0086] Example 38 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 0.50% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.75% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.75% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 38 was obtained by the same method as in Example 1.

[0087] Example 39 As the polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As the carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 1.50% of the wood flour was used. As the polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.025% of the wood flour was used. As the polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.025% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 39 was obtained by the same method as in Example 1.

[0088] Example 40 As a polyolefin resin containing plant fibers, a resin material A-2 (manufactured by I-Composites Co., Ltd.) consisting of 55% coniferous wood flour and 45% polypropylene (PP) was used. As a carbodiimide, the same cyclic compound B-1 as in Example 1 was used, and 1.50% of the wood flour was used. As a polyamine, polyethyleneimine C-1 (product name: Epomin R, product number: SP-200, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 10,000 was used, and 0.75% of the wood flour was used. As a polyoxazoline, polyoxazoline C-3 (product name: Epocross R, product number: WS-700, manufactured by Nippon Shokubai Co., Ltd.) with a weight average molecular weight of 40,000 was used, and 0.75% of the wood flour was used. Using these materials, a strip-shaped test piece of Example 40 was obtained by the same method as in Example 1.

[0089] Comparative Example 1 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, N,N'-dicyclohexylcarbodiimide B-5 was used in an amount of 0.10% relative to the wood flour. Using these materials, a rectangular test piece of Comparative Example 1 was obtained by the same method as in Example 1.

[0090] Comparative Example 2 As a polyolefin resin containing plant fibers, a resin material A-1 (manufactured by I-Composites Co., Ltd.) consisting of 55% hardwood-derived wood flour and 45% polypropylene (PP) was used. As a carbodiimide, N,N'-dicyclohexylcarbodiimide B-5 was used in an amount of 5.00% based on the wood flour. Using these materials, a rectangular test piece for Comparative Example 2 was obtained by the same method as in Example 1.

[0091] (Evaluation of isocyanate gas generation amount) The test pieces of Examples 1 to 40 and Comparative Examples 1 to 2 were analyzed using pyrolysis GC / MS. The GC / MS was a GC-MS-QP2020 NX manufactured by Shimadzu Corporation, the pretreatment device was an EGA / PY-3030D manufactured by Frontier Labs, and the column was a UA +5 manufactured by Frontier Labs. The amount of isocyanate gas generated was evaluated on a five-level scale, A to E, based on the amount of isocyanate gas detected by pyrolysis GC / MS. The evaluation was as follows: A if no isocyanate gas was detected; B if less than 20 ppm of isocyanate gas was detected; C if 20 ppm or more but less than 50 ppm of isocyanate gas was detected; D if 50 ppm or more but less than 100 ppm of isocyanate gas was detected; and E if 100 ppm or more of isocyanate gas was detected. FIG. 6 shows the evaluation results of the amount of isocyanate gas generated in Examples 1 to 40 and Comparative Examples 1 and 2.

[0092] (Evaluation of releasability) The contact area between the test piece and the mold after the ejection step of the injection molding in the manufacturing process of the test piece of Examples 1 to 40 and Comparative Examples 1 to 2 was visually checked, and the mold releasability was evaluated on a five-level scale of A to E. The evaluation was as follows: A when 100% of the surface of the test piece was separated from the mold; B when 70% or more and less than 100% of the surface of the test piece was separated from the mold; C when 50% or more and less than 70% of the surface of the test piece was separated from the mold; D when 20% or more and less than 50% of the surface of the test piece was separated from the mold; and E when less than 20% of the surface of the test piece was separated from the mold. FIG. 6 shows the evaluation results of the mold releasability of Examples 1 to 40 and Comparative Examples 1 to 2.

[0093] (Corrosivity evaluation) The test pieces of Examples 1 to 40 and Comparative Examples 1 to 2 were continuously produced in an amount of 100 pieces each. The state of the surface of the mold was confirmed every time a test piece was produced, and the corrosiveness was evaluated on a scale of 5 from A to E according to the number of test pieces produced until the surface of the mold was contaminated. Here, the surface of the mold was contaminated when rust was confirmed on the surface of the mold. The evaluation was as follows: A when no contamination of the mold surface was confirmed when 100 test pieces were produced; B when contamination of the mold surface was confirmed when 31 to 99 test pieces were produced; C when contamination of the mold surface was confirmed when 11 to 30 test pieces were produced; D when contamination of the mold surface was confirmed when 2 to 10 test pieces were produced; and E when contamination of the mold surface was confirmed when one test piece was produced. FIG. 6 shows the evaluation results of the corrosiveness of Examples 1 to 40 and Comparative Examples 1 to 2.

[0094] (Evaluation of heat resistance) The deflection temperature under load of the test pieces of Examples 1 to 40 and Comparative Examples 1 and 2 was measured in accordance with ISO-75 at a load of 0.45 MPa and a heating rate of 2°C / min. The measurement was performed three times for each test piece, and the heat resistance was evaluated on a five-level scale of A to E based on the average of the measurements. When the deflection temperature under load was 140°C or higher, it was rated as A; when the deflection temperature under load was 130°C or higher and lower than 140°C, it was rated as B; when the deflection temperature under load was 120°C or higher and lower than 130°C, it was rated as C; when the deflection temperature under load was 100°C or higher and lower than 120°C, it was rated as D; and when the deflection temperature under load was lower than 100°C, it was rated as E. The evaluation results of the heat resistance of Examples 1 to 40 and Comparative Examples 1 and 2 are shown together in FIG. 6.

[0095] As is clear from FIG. 6, Examples 1 to 40, which are resin compositions obtained by kneading plant fibers, a polyolefin resin, and at least one of a first cyclic compound, a second cyclic compound, a third cyclic compound, and a fourth cyclic compound, are able to suppress corrosion of the mold during injection molding and prevent the generation of isocyanate gas.

[0096] From the results of Examples 9 to 40, when polyamine or polyoxazoline is contained, the mold surface was not contaminated at least when 30 test pieces were prepared in the evaluation of corrosiveness, so it is clear that better corrosiveness can be ensured. Also, in the evaluation of releasability and heat resistance, the evaluation was B or A, so it is clear that better releasability and heat resistance can be ensured by containing polyamine or polyoxazoline.

[0097] From the results of Examples 25 to 40, it is clear that when wood flour derived from coniferous trees is used as the plant fiber and polyethyleneimine having a weight average molecular weight of 10,000 is used as the polyamine, the deflection temperature under load is 140°C or higher in the heat resistance evaluation, thereby ensuring superior heat resistance.

[0098] In contrast, Comparative Examples 1 and 2, which are resin compositions obtained by kneading plant fibers, a polyolefin resin, and N,N'-dicyclohexylcarbodiimide, a carbodiimide in which the first and second nitrogens are bonded to each other via a bonding group and an unsubstituted aromatic is bonded to each of the first and second nitrogens, fail to suppress the generation of isocyanate gas. In addition, in the evaluation of releasability, less than 20% of the test piece's surface was separated from the mold, meaning that sufficient releasability from the mold during injection molding was not ensured.

[0099] As described above, according to the resin composition, the resin molded product, and the method for producing resin pellets of the present invention, it is possible to suppress corrosion of the mold during injection molding and to suppress the generation of isocyanate gas. [Explanation of symbols]

[0100] 10. Plant Fiber 10A Corrosive gas 11 Polyolefin resin 12 Polyolefin resin containing plant fibers 20 cyclic compounds 30 Resin composition 31 Resin molding 32 Resin pellets 40 Twin screw mixer 41 Molding machine 50 Polyamines

Claims

1. Plant fibers and, Polyolefin resins, At least one of the following: a first-cyclic compound, a second-cyclic compound, a third-cyclic compound, and a fourth-cyclic compound, A method for producing a resin composition, comprising the step of kneading a polyamine having at least one primary amine and a secondary amine with at least one polyoxazoline to obtain a resin composition, If the polyamine is included, the weight-average molecular weight of the polyamine is 300 to 100,000. If the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 300 to 100,000. The first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide in which the first and second nitrogen atoms are bonded by a bonding group, and two or more first subcyclic structures condensed onto a part of the main cyclic structure. The aforementioned second cyclic compound is a cyclic compound having the main cyclic structure and two or more second subcyclic structures extending from the main cyclic structure as substituents, The third cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed to a part of the main cyclic structure, and the second subcyclic structure extending as substituents from each of the first subcyclic structures. A method for producing a resin composition wherein the fourth cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed on a part of the main cyclic structure, and the second subcyclic structure condensed on a part of the first subcyclic structure.

2. A method for producing the resin composition according to Claim 1, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 100,000. A method for producing a resin composition, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 100,000.

3. A method for producing the resin composition according to Claim 2, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 70,000. A method for producing a resin composition, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 70,000.

4. A method for producing the resin composition according to any one of claims 1 to 3, A method for producing a resin composition in which the polyamine is polyethyleneimine.

5. A method for producing the resin composition according to any one of claims 1 to 3, A method for producing a resin composition in which the plant fibers are wood powder derived from coniferous trees.

6. Plant fibers and, Polyolefin resins, At least one of the following: a first-cyclic compound, a second-cyclic compound, a third-cyclic compound, and a fourth-cyclic compound, A method for producing a resin molded article, comprising a molding step of molding a resin composition containing a polyamine having at least one of a primary amine and a secondary amine, and at least one of polyoxazolines, into a component of equipment having a heat source with a temperature of 300°C or lower, If the polyamine is included, the weight-average molecular weight of the polyamine is 300 to 100,000. If the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 300 to 100,000. The first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide in which the first and second nitrogen atoms are bonded by a bonding group, and two or more first subcyclic structures condensed onto a part of the main cyclic structure. The aforementioned second cyclic compound is a cyclic compound having the main cyclic structure and two or more second subcyclic structures extending from the main cyclic structure as substituents, The third cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed to a part of the main cyclic structure, and the second subcyclic structure extending as substituents from each of the first subcyclic structures. A method for producing a resin molded article, wherein the fourth cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed on a part of the main cyclic structure, and the second subcyclic structure condensed on a part of the first subcyclic structure.

7. A method for manufacturing a resin molded article according to claim 6, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 100,000. A method for producing a resin molded article, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 100,000.

8. A method for manufacturing a resin molded article according to Claim 7, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 70,000. A method for producing a resin molded article, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 70,000.

9. A method for manufacturing a resin molded article according to claim 6, A method for manufacturing a resin molded body in which the aforementioned component is a housing or bracket for a vehicle light fixture.

10. Plant fibers and, Polyolefin resins, At least one of the following: a first-cyclic compound, a second-cyclic compound, a third-cyclic compound, and a fourth-cyclic compound, A step of kneading a polyamine having at least one primary amine and a secondary amine, and at least one polyoxazoline, to obtain a resin composition, A method for producing resin pellets, comprising a molding step of forming the resin composition into pellets, If the polyamine is included, the weight-average molecular weight of the polyamine is 300 to 100,000. If the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 300 to 100,000. The first cyclic compound is a cyclic compound having a main cyclic structure containing a carbodiimide in which the first and second nitrogen atoms are bonded by a bonding group, and two or more first subcyclic structures condensed onto a part of the main cyclic structure. The aforementioned second cyclic compound is a cyclic compound having the main cyclic structure and two or more second subcyclic structures extending from the main cyclic structure as substituents, The third cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed to a part of the main cyclic structure, and the second subcyclic structure extending as substituents from each of the first subcyclic structures. A method for producing resin pellets, wherein the fourth cyclic compound is a cyclic compound having the main cyclic structure, the first subcyclic structure condensed on a part of the main cyclic structure, and the second subcyclic structure condensed on a part of the first subcyclic structure.

11. A method for producing resin pellets according to claim 10, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 100,000. A method for producing resin pellets, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 100,000.

12. A method for producing resin pellets according to claim 11, If the polyamine is included, the weight-average molecular weight of the polyamine is 10,000 to 70,000. A method for producing resin pellets, wherein, if the polyoxazoline is included, the weight-average molecular weight of the polyoxazoline is 10,000 to 70,000.

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