Material for molding, molded body, and method for manufacturing molded body

Abstract

To provide a material for molding which contains polyurethane, enables injection molding, and has a high degree of freedom of molding, a molded body which contains polyurethane and is excellent in both impact strength and flexural strength, and a method for manufacturing a molded body which can manufacture a molded body that contains polyurethane and is excellent in both impact strength and flexural strength.SOLUTION: A material for molding contains a cellulose fiber, a resin which is molten at 200°C or less, and polyurethane, and has a heterocyclic viscosity at 180°C of 3000 Pa s or more and 147000 Pa s or less. The resin is preferably at least one selected from the group consisting of polypropylene and a polylactic acid.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a molding material, a molded body, and a method for producing a molded body. [Background technology]

[0002] In recent years, there has been a social movement to recycle various plastic materials such as polyester, thereby making effective use of resources and reducing waste and saving energy.

[0003] Patent Document 1 describes a wood substitute material obtained by heating and compressing a fiber mass formed by entangling 100 parts by mass of recovered fiber with 30 to 50 parts by mass of thermoplastic resin fiber having a melting point lower than the temperature at which the recovered fiber deteriorates, at a temperature higher than the melting point of the thermoplastic resin fiber but at which the recovered fiber does not deteriorate, and having a density of 0.4 to 0.7 g / cm 3 A wood substitute for packaging is disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-025857 A Summary of the Invention [Problem to be solved by the invention]

[0005] Polyurethane is characterized by its excellent elasticity and flexibility and is used in various products such as clothing.

[0006] However, polyurethane is difficult to recycle because it generates toxic gases (amine-containing compounds, etc.) and odors when thermally decomposed. In addition, although Patent Document 1 discloses compression molding, when recycled fibers containing polyurethane are used, a molded body with sufficiently high mechanical strength cannot be obtained. In addition, the technology described in Patent Document 1 does not allow injection molding when recycled fibers containing polyurethane are used, and the degree of freedom in molding is low. [Means for solving the problem]

[0007] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0008] The molding material according to the application example of the present invention includes cellulose fibers, a resin that melts at 200°C or less, and polyurethane, The complex viscosity at 180°C is 3,000 Pa s or more and 147,000 Pa s or less.

[0009] The molded article according to the application example of the present invention is made of the molding material according to the application example of the present invention.

[0010] A method for producing a molded article according to an application example of the present invention comprises molding the molding material according to an application example of the present invention while heating it to a temperature at which the resin melts. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a table showing the composition of the molding material, the complex viscosity of the molding material at 180° C., and the evaluation results for each of the examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Preferred embodiments of the present invention will now be described in detail. [1] Molding material

[0013] First, the molding material of the present invention will be described. The molding material of the present invention contains cellulose fibers, a resin that melts at 200°C or lower, and polyurethane, and has a complex viscosity at 180°C of 3000 Pa·s or more and 147000 Pa·s or less.

[0014] With this configuration, it is possible to provide a molding material that contains polyurethane, can be injection molded, and has a high degree of freedom in molding. It is also possible to provide a molding material that can be suitably used to manufacture a molded body that is excellent in mechanical strength, particularly both impact strength and flexural strength. In addition, it is possible to improve the moldability of the molded body, thereby improving the productivity of the molded body. In particular, by including a resin that melts at 200°C or less, it is possible to suitably mold the molding material at a temperature where the thermal decomposition of the polyurethane is sufficiently prevented.

[0015] In addition, although polyurethane is found in large quantities in waste clothing and the like, it generates toxic gases upon thermal decomposition, making it difficult to recycle and also difficult to incinerate in the past. However, according to the present invention, such polyurethane can be suitably reused.

[0016] Furthermore, by containing cellulose fibers, which are abundant natural materials derived from plants, it is possible to appropriately address environmental issues and save buried resources, etc., and it is also advantageous from the viewpoints of stable supply of molding materials and molded articles produced using the same, cost reduction, etc. Furthermore, cellulose fibers are a component that is contained in large amounts not only in virgin pulp but also in waste paper, old cloth, etc., and it is also advantageous from the viewpoint of promoting effective reuse of resources.

[0017] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, even if a molding material contains a resin and polyurethane that melt at 200°C or below, if it does not contain cellulose fibers, the elastic modulus and shape retention of the molded body produced using the molding material will be significantly low.

[0018] Furthermore, even if the molding material contains cellulose fibers and a resin that melts at 200° C. or less, if it does not contain polyurethane, a problem occurs in that the impact strength decreases.

[0019] Furthermore, even if the molding material contains cellulose fiber and polyurethane, if it does not contain a resin that melts at 200°C or less, the moldability of the molded product will be significantly reduced, such as the inability to perform injection molding, etc. Furthermore, due to the reduced moldability, the mechanical strength of the manufactured molded product will also be poor.

[0020] Furthermore, when a resin having a melting point of more than 200° C. is used as a molding material instead of a resin that melts at 200° C. or less, the degree of freedom in molding cannot be sufficiently increased, and, for example, injection molding becomes impossible. Furthermore, a molded product produced using such a molding material has poor mechanical strength.

[0021] If the complex viscosity of the molding material at 180° C. is less than the lower limit, problems such as poor metering during injection molding, flash in the molded product, and the generation of air bubbles in the molded product occur.

[0022] Furthermore, if the complex viscosity of the molding material at 180° C. exceeds the upper limit, the short mold of the molded product, the injection molding machine, and the mold are likely to be damaged.

[0023] In the present invention, the complex viscosity refers to dynamic viscoelasticity measured by rheometer measurement. The complex viscosity can be measured under the following conditions: starting temperature: 100°C, step temperature: 1°C, end temperature: 200°C, heating rate: 5°C / min, strain control: 0.1 deg, frequency: 1 Hz, automatic control: ON, waveform: sine wave, continuous vibration: ON, average number: 3, weight control: OFF, and with a sample of 1 mm thickness sandwiched between parallel plates, the lower plate is subjected to angular vibration. The complex viscosity can be measured, for example, using a Pheosol-G3000 (manufactured by UBM).

[0024] As described above, the complex viscosity of the molding material of the present invention at 180°C may be from 3000 Pa·s to 147000 Pa·s, preferably from 4000 Pa·s to 140000 Pa·s, more preferably from 5000 Pa·s to 90000 Pa·s, and even more preferably from 7000 Pa·s to 40000 Pa·s. This makes the above-mentioned effects more pronounced.

[0025] [1-1] Cellulose fiber The molding material of the present invention contains cellulose fibers.

[0026] Cellulose fibers are a component that greatly contributes to maintaining the shape of a molded article produced using the molding material of the present invention, and also has a significant effect on the properties of the molded article, such as its strength.

[0027] Cellulose is a plant-derived, abundant natural material. Therefore, the use of cellulose fibers can suitably address environmental issues and save buried resources, and is also preferable from the viewpoints of stable supply of molding materials and molded articles produced using the same, cost reduction, etc. Furthermore, among various fibers, cellulose fibers have particularly high theoretical strength, and are advantageous from the viewpoint of improving the strength of molded articles.

[0028] As the cellulose fibers, virgin pulp may be used, or recycled waste paper, old cloth, etc. may be used.

[0029] Cellulosic fibers are generally composed mainly of cellulose, but may contain components other than cellulose, such as hemicellulose and lignin.

[0030] The cellulose fibers used may be those that have been subjected to a treatment such as bleaching. Examples of cellulose fibers include cotton, hemp, rayon, and cupra.

[0031] The average length of the cellulose fibers is not particularly limited, but is preferably 50 μm or more and less than 3 mm, more preferably 70 μm or more and less than 500 μm, and even more preferably 100 μm or more and less than 400 μm.

[0032] This makes it possible to improve the shape stability, strength, etc. of a molded body produced using the molding material. In addition, dust generation in a molded body produced using the molding material can be more effectively prevented or suppressed. In addition, it is possible to more effectively prevent the occurrence of undesired irregularities on the surface of a molded body produced using the molding material. The fiber length is determined by a method conforming to ISO 16065-2:2007.

[0033] The average diameter of the cellulose fibers is not particularly limited, but is preferably 3 μm or more and less than 100 μm, more preferably 4 μm or more and less than 50 μm, and even more preferably 5 μm or more and less than 20 μm.

[0034] This makes it possible to improve the stability of shape, strength, etc. of the molded article produced using the molding material. In addition, it is possible to more effectively prevent the occurrence of undesired irregularities on the surface of the molded article produced using the molding material.

[0035] The average aspect ratio of the cellulose fibers, that is, the average length to the average diameter, is not particularly limited, but is preferably 10 or more and 1,000 or less, and more preferably 15 or more and 100 or less.

[0036] This makes it possible to improve the stability of shape, strength, etc. of the molded body produced using the molding material. In addition, dust generation in the molded body produced using the molding material can be more effectively prevented or suppressed. In addition, it is possible to more effectively prevent the occurrence of undesired irregularities on the surface of the molded body produced using the molding material.

[0037] The content of cellulose fibers in the molding material of the present invention is preferably 2.0% by mass or more and 40.0% by mass or less, more preferably 3.0% by mass or more and 35.0% by mass or less, and even more preferably 5.0% by mass or more and 30.0% by mass or less.

[0038] This makes it easier to adjust the complex viscosity of the molding material at 180° C. to a more suitable range, and the above-mentioned effects of the present invention are more significantly exhibited.

[0039] [1-2] Resin that melts at 200℃ or less The molding material of the present invention contains a resin that melts at 200° C. or lower, that is, a resin having a melting point of 200° C. or lower. However, the resin does not include polyurethane.

[0040] By including the resin, the toughness of a molded article produced using the molding material of the present invention can be increased, and the impact resistance of the molded article can be made sufficiently excellent.

[0041] The melting point of the resin may be 200°C or lower, but is preferably 115°C or higher and 185°C or lower, and more preferably 145°C or higher and 180°C or lower.

[0042] The resin may be one that melts by itself at 200° C. or less, but is preferably one that is compatible with polyurethane at 200° C. or less.

[0043] This allows for greater freedom in molding, and the produced molded article has superior mechanical strength.

[0044] Examples of the resin include polyolefins such as polyethylene and polypropylene, and polyesters such as aliphatic polyesters and aromatic polyesters. One or a combination of two or more selected from these may be used, but at least one selected from the group consisting of polypropylene and polylactic acid is preferred.

[0045] This makes it possible to improve the compatibility between the resin and the polyurethane, and the above-mentioned effects are more significantly exhibited.

[0046] In particular, by using polylactic acid derived from biomass raw materials, consumption of buried resources can be more effectively reduced.

[0047] In addition, in the present invention, the above-mentioned excellent effects can be obtained even when recycled polypropylene is used. More specifically, recycled polypropylene generally has a problem that the molecular weight is reduced due to thermal decomposition during recycling, and the viscosity and moldability are reduced, but in the present invention, excellent injection moldability can be ensured even when recycled polypropylene is used.

[0048] Aliphatic polyester is a polyester that does not have an aromatic chemical structure, and all of the constituent monomers do not have an aromatic chemical structure. Examples of aliphatic polyesters include those in which both the polyvalent carboxylic acid component and the polyhydric alcohol component as the constituent monomers have an aliphatic alkylene group. In addition, the aliphatic polyester may be one that is composed of a monomer that has a hydroxyl group and a carboxyl group in the molecule. Examples of aliphatic polyesters that are composed of a monomer that has a hydroxyl group and a carboxyl group in the molecule include polylactic acid.

[0049] When the aliphatic polyester has a chemical structure in which a polycarboxylic acid component having an aliphatic alkylene group and a polyhydric alcohol component having an aliphatic alkylene group are polymerized, the aliphatic polyester preferably has a chemical structure in which an alkylene dicarboxylic acid having an alkylene group with a carbon chain length of 2 or more and 6 or less and an alkylene diol having an alkylene group with a carbon chain length of 2 or more and 8 or less are condensed.

[0050] This allows the above-mentioned effects to be exhibited more significantly, and also allows the compatibility with polyurethane to be improved, allowing the above-mentioned effects to be exhibited more significantly.

[0051] The carbon chain length of the alkylene group in the alkylene dicarboxylic acid is preferably 2 or more and 6 or less, more preferably 2 or more and 5 or less, and even more preferably 2 or more and 4 or less. This makes the above-mentioned effects more pronounced.

[0052] The alkylene group of the alkylene dicarboxylic acid may have a branched structure, but is preferably linear. This makes the above-mentioned effects more pronounced.

[0053] Examples of the alkylene dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and one or more selected from these may be used in combination.

[0054] The carbon chain length of the alkylene group in the alkylene diol is preferably 2 or more and 8 or less, more preferably 2 or more and 6 or less, and even more preferably 3 or more and 5 or less. This makes the above-mentioned effects more pronounced.

[0055] The alkylene group of the alkylene diol may have a branched structure, but is preferably linear. This makes the above-mentioned effects more pronounced.

[0056] Examples of the alkylene diol include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol. One or a combination of two or more selected from these can be used.

[0057] Specific examples of aliphatic polyesters containing alkylene dicarboxylic acids and alkylene diols as monomer components that satisfy the above conditions include polybutylene succinate, polybutylene succinate adipate, polyethylene adipate, etc., and one or more selected from these may be used in combination.

[0058] These materials are biodegradable and can more appropriately reduce the environmental impact of molded articles. In addition, these materials are relatively inexpensive and can be easily and stably obtained. Therefore, they are advantageous from the viewpoints of stable supply of molding materials and molded articles, cost reduction, etc.

[0059] The content of the resin in the molding material of the present invention is not particularly limited, but is preferably 15.0% by mass or more and 90.0% by mass or less, more preferably 25.0% by mass or more and 85.0% by mass or less, and even more preferably 45.0% by mass or more and 80.0% by mass or less.

[0060] This makes it easier to adjust the complex viscosity of the molding material at 180° C. to a more suitable range, and the above-mentioned effects of the present invention are more significantly exhibited.

[0061] In the molding material of the present invention, when the content of the cellulose fiber is XC [% by mass] and the content of the resin is XR [% by mass], it is preferable to satisfy the relationship of 0.03≦XC / XR≦0.60, it is more preferable to satisfy the relationship of 0.04≦XC / XR≦0.50, and it is even more preferable to satisfy the relationship of 0.07≦XC / XR≦0.45.

[0062] This makes it easier to adjust the complex viscosity of the molding material at 180° C. to a more suitable range, and the above-mentioned effects of the present invention are more significantly exhibited.

[0063] [1-3] Polyurethane The molding material of the present invention includes polyurethane.

[0064] Polyurethane is generally a component that has excellent affinity with both the cellulose fibers and the resins.

[0065] The polyurethane usually becomes compatible with the resin during the process of producing a molded article using the molding material of the present invention, particularly during the heat treatment during molding.

[0066] This makes it possible to improve the bending strength of a molded article produced using the molding material of the present invention.

[0067] The number average molecular weight of the polyurethane is preferably 20,000 or more and 300,000 or less, more preferably 30,000 or more and 200,000 or less, and even more preferably 40,000 or more and 150,000 or less.

[0068] This makes it possible to improve the affinity of the polyurethane with the cellulose fibers and the resin, and to improve the impact strength and flexural strength of the molded article produced using the molding material.

[0069] The polyurethane may be contained in the molding material in any form, such as a powder, but may also be contained in the form of fibers. This allows, for example, polyurethane derived from waste clothing to be suitably used.

[0070] The content of polyurethane in the molding material of the present invention is preferably from 0.3 to 6.0% by mass, more preferably from 0.5 to 5.0% by mass, and even more preferably from 1.0 to 3.2% by mass.

[0071] This makes it easier to adjust the complex viscosity of the molding material at 180° C. to a more suitable range, and the above-mentioned effects of the present invention are more significantly exhibited.

[0072] The sum of the content of the resin and the content of the polyurethane in the molding material of the present invention is preferably 25.0 mass% or more and 91.0 mass% or less, more preferably 30.0 mass% or more and 88.0 mass% or less, and even more preferably 45.0 mass% or more and 80.0 mass% or less.

[0073] This makes it easier to adjust the complex viscosity of the molding material at 180° C. to a more suitable range, and the above-mentioned effects of the present invention are more significantly exhibited.

[0074] In the molding material of the present invention, when the content of the resin is XR [mass%] and the content of polyurethane is XU [mass%], it is preferable to satisfy the relationship of 0.01≦XU / XR≦0.30, it is more preferable to satisfy the relationship of 0.02≦XU / XR≦0.20, and it is even more preferable to satisfy the relationship of 0.03≦XU / XR≦0.10.

[0075] This makes it easier to adjust the complex viscosity of the molding material at 180°C to a more suitable range, and the effects of the present invention described above are more pronounced. In particular, the impact strength and flexural strength of a molded article produced using the molding material can be made even better.

[0076] When the content of cellulose fiber in the molding material of the present invention is XC [mass%] and the content of polyurethane is XU [mass%], it is preferable to satisfy the relationship of 0.01≦XU / XC≦3.0, it is more preferable to satisfy the relationship of 0.02≦XU / XC≦1.6, and it is even more preferable to satisfy the relationship of 0.03≦XU / XC≦0.6.

[0077] This makes it easier to adjust the complex viscosity of the molding material at 180°C to a more suitable range, and the effects of the present invention described above are more pronounced. In particular, the impact strength and flexural strength of a molded article produced using the molding material can be made even better.

[0078] [1-4] Other fibers The molding material of the present invention may further contain fibers other than those mentioned above, in addition to the above-mentioned cellulose fibers, resin, and polyurethane. Hereinafter, such fibers are also referred to as "other fibers". By including other fibers, for example, the strength of the molded body can be further increased.

[0079] Examples of other fibers include fibers made of resin materials, more specifically, polyester fibers, acrylic fibers, nylon fibers, acetate fibers, etc. However, the other fibers are made of materials that do not melt at 200°C, and remain in a fibrous state when the molding material is heated to 200°C.

[0080] The average length of the other fibers is not particularly limited, but is preferably less than 3 mm, more preferably 50 μm or more and less than 500 μm, and even more preferably 100 μm or more and less than 400 μm.

[0081] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0082] The average diameter of the other fibers is not particularly limited, but is preferably less than 100 μm, more preferably 3 μm or more and less than 50 μm, and even more preferably 5 μm or more and less than 20 μm.

[0083] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0084] The average aspect ratio of the other fibers, that is, the average length to the average diameter, is not particularly limited, but is preferably 10 or more and 1,000 or less, and more preferably 15 or more and 100 or less.

[0085] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0086] The content of other fibers in the molding material of the present invention is preferably 1.0% by mass or more and 30.0% by mass or less, more preferably 2.0% by mass or more and 25.0% by mass or less, and even more preferably 3.0% by mass or more and 20.0% by mass or less.

[0087] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0088] In the molding material of the present invention, when the content of the resin is XR [% by mass] and the content of other fibers is XO [% by mass], it is preferable to satisfy the relationship of 0.03≦XO / XR≦3.0, it is more preferable to satisfy the relationship of 0.05≦XO / XR≦2.0, and it is even more preferable to satisfy the relationship of 0.10≦XO / XR≦0.80.

[0089] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0090] When the content of cellulose fiber in the molding material of the present invention is XC [% by mass] and the content of other fibers is XO [% by mass], it is preferable to satisfy the relationship of 0.1≦XO / XC≦3.8, it is more preferable to satisfy the relationship of 0.2≦XO / XC≦2.1, and it is even more preferable to satisfy the relationship of 0.3≦XO / XC≦1.7.

[0091] This makes it possible to improve the impact strength and bending strength of a molded article produced using the molding material.

[0092] [1-5] Flame retardants The molding material of the present invention may further contain a flame retardant.

[0093] Examples of the flame retardant include inorganic flame retardants such as antimony compounds, metal hydroxides, nitrogen compounds, and boron compounds, and organic flame retardants such as bromine compounds and phosphorus compounds.

[0094] When the molding material contains a flame retardant, the content of the flame retardant can be 1.0 part by mass or more and 20.0 parts by mass or less when the total content of the cellulose fiber, the resin, and the polyurethane is 100.0 parts by mass.

[0095] This makes it possible to more effectively exert the effects of the present invention described above, while at the same time making it possible to provide a molded article produced using the molding material of the present invention with more excellent flame retardancy.

[0096] [1-6] Other ingredients The molding material of the present invention may contain components other than those described above. Hereinafter, in this section, such components will also be referred to as "other components".

[0097] Examples of other components include colorants, insect repellents, antifungal agents, antioxidants, ultraviolet absorbers, aggregation inhibitors, release agents, and resin materials other than those mentioned above.

[0098] However, the content of other components in the molding material of the present invention is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0099] [2] Manufacturing method of molding material Next, the method for producing the molding material of the present invention will be described.

[0100] The molding material of the present invention can be produced, for example, by mixing the above-mentioned components. In this case, the components may be mixed at the same time or at different times.

[0101] The molding material of the present invention may be produced, for example, by kneading the above-mentioned components. The components can be kneaded using, for example, a single-screw kneader or a twin-screw kneader.

[0102] The temperature of the materials during kneading is preferably less than 200°C, more preferably from 120°C to 190°C, and even more preferably from 150°C to 180°C.

[0103] The strand-like molding material obtained by kneading may be pelletized, for example, using a pelletizer of the strand type or watering hot cut type to form a pellet-like molding material.

[0104] The following method may also be applied as a method for producing a molding material. That is, the kneaded material of the above-mentioned components may be formed into a sheet, and then, for example, cut into a desired shape using a shredder device to obtain a pellet-shaped molding material. The method for forming the kneaded material into a sheet is not particularly limited, but for example, the kneaded material is first deposited in air to form a sheet-shaped deposit, and the deposit is compressed using a calendar device to remove air and increase the density, and then heated in a non-contact manner using a heating furnace, and then hot-pressed using a heat press device. The shape and size of the pellets obtained by cutting are not particularly limited, but for example, they can be approximately rectangular parallelepipeds with a side length of 2 mm to 5 mm.

[0105] The cellulose fibers used in the production of the molding material of the present invention may be those that have been previously subjected to a defibration treatment. In particular, cellulose fiber sources containing cellulose fibers, such as waste paper and old cloth, may be used that have been defibrated.

[0106] In addition, when the molding material of the present invention contains fibrous polyurethane, i.e., urethane fibers, the urethane fibers used in the production of the molding material may be ones that have been previously subjected to a fiber-opening treatment. In particular, urethane fiber sources containing urethane fibers, such as old cloth, may be used that have been fiber-opened.

[0107] In addition, when the molding material of the present invention contains other fibers, the other fibers used in the production of the molding material of the present invention may be ones that have been previously subjected to a defibration treatment. In particular, defibrated other fiber sources containing other fibers, such as old cloth, may be used.

[0108] The fiber sources as described above, i.e., cellulose fiber sources, urethane fiber sources, and other fiber sources, may be comminuted before being defibrated.

[0109] The fiber source can be crushed by, for example, cutting into small pieces using a shredder having a crushing blade in an atmosphere such as the air. The shape of the small pieces is, for example, approximately a cube or rectangular parallelepiped with a few mm square.

[0110] The small pieces of the fiber source are defibrated to become unraveled fibers. Defibration here refers to the process of unraveling a plurality of fibers that are united together into individual fibers.

[0111] Defibration can be suitably carried out under dry conditions. The term "dry" used here means that the defibration is carried out in air such as the atmosphere, not in a liquid. For the purpose of preventing static electricity, for example, water may be sprayed onto the fibers. Dry defibration can be suitably carried out, for example, by air current.

[0112] The fiber sources may be defibrated separately for each fiber source, or may be defibrated in a state where multiple types of fiber sources are mixed together.

[0113] The fiber source may contain multiple types of fibers, more specifically, two or more types of cellulose fibers, urethane fibers, and other fibers. Examples of fiber sources containing two or more types of fibers include blended fibers.

[0114] The fiber source may be defibrated in a state in which it contains components other than fibers, such as the above-mentioned resin, non-fibrous polyurethane, flame retardant, and other components.

[0115] [3] Molded body Next, the molded article of the present invention will be described.

[0116] The molded article of the present invention is made of the above-mentioned molding material of the present invention. With this configuration, it is possible to provide a molded article that contains polyurethane and has excellent impact strength and flexural strength.

[0117] Furthermore, by containing cellulose fibers, which are abundant natural materials derived from plants, it is possible to appropriately address environmental issues and save buried resources, etc., and is also advantageous from the viewpoints of stable supply of molded bodies, cost reduction, etc. Furthermore, cellulose fibers are a component that is contained in large amounts not only in virgin pulp but also in waste paper, used cloth, etc., and are also advantageous from the viewpoint of promoting effective reuse of resources.

[0118] Although polyurethane is found in large amounts in waste clothing and the like, when it is mixed with other components, such as in blended textiles, it is difficult to isolate it from the other components. In addition, it generates toxic gases when thermally processed at 200°C or above, so in the past it was difficult to reuse it and incinerate it. However, according to the present invention, polyurethane contained in waste clothing and the like can be suitably reused.

[0119] The molded article of the present invention may have a portion constituted by the molding material of the present invention described above, and may also have a portion constituted by a material other than the molding material of the present invention.

[0120] Each component constituting the molded article preferably satisfies the conditions described above in [1-1] to [1-6].

[0121] The shape of the molded product is not particularly limited, and may be any shape, such as a sheet, a block, a sphere, or a three-dimensional shape.

[0122] The molded article may be used for any purpose, but is preferably used in an environment where dust generation or the like is a problem, more specifically, for example, a component having a fluid flow path, a component arranged around the component, an ink cartridge, various containers, various fixtures, etc. Conventional molded articles manufactured using materials containing cellulose fibers and resins have the problem of being prone to dust generation, and are therefore unsuitable for use in environments where dust generation or the like is a problem, as described above. In contrast, the molded article according to the present invention is less prone to dust generation. Therefore, when applied to the above-mentioned applications, the effects of the present invention are more pronounced.

[0123] [4] Manufacturing method of molded body Next, the method for producing the molded article of the present invention will be described.

[0124] The method for producing the molded article comprises molding the molding material of the present invention while heating it to a temperature at which the resin melts.

[0125] This makes it possible to provide a method for producing a molded article that contains polyurethane and that is capable of producing a molded article that is excellent in both impact strength and flexural strength.

[0126] The molding method may be, for example, compression molding, extrusion molding, or the like, but injection molding is preferred.

[0127] This makes it possible to suitably manufacture even molded articles having a complex structure or a fine structure.

[0128] The heating temperature of the molding material during molding is preferably less than 200°C, more preferably from 120°C to 190°C, and even more preferably from 150°C to 180°C.

[0129] This makes it possible to more effectively prevent thermal decomposition of the polyurethane, while improving moldability and productivity of the molded article, and also improve the mechanical strength of the molded article produced.

[0130] After the above-mentioned molding, post-treatments such as machining, eg grinding and polishing, painting, plating, etc. may be carried out.

[0131] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these. EXAMPLES

[0132] Next, specific examples of the present invention will be described. [5] Preparation of molding material

[0133] Example 1 First, collected clothing from the market containing cellulose fibers, urethane fibers, acrylic fibers and polyester fibers was prepared as a fiber source.

[0134] This fiber source was shredded in the atmosphere into roughly cubes of several mm square using a shredder equipped with a coarse-crushing blade, and then defibrated by blowing an air current onto the shredded material.

[0135] The mass ratio of cellulose fibers, urethane fibers, acrylic fibers and polyester fibers in the obtained defibrated material was 3.8:0.7:3.1:2.4.

[0136] 10.0 parts by mass of the defibrated material obtained as described above and 90.0 parts by mass of polypropylene (H700, manufactured by Prime Polymer Co., Ltd.) as a resin that melts at 200°C or less were weighed. These were then put into a twin-screw kneader (KZW15TW-45MG, manufactured by Technovel Co., Ltd.) and kneaded. The kneading conditions were a maximum heating temperature of 180°C and an extrusion discharge rate of 1 kg / hr. Next, the material was processed into a strand shape and then pelletized into a molding material in a pelletizer.

[0137] The average length of the cellulose fibers contained in the molding material was 1.5 mm, the average diameter of the cellulose fibers was 15 μm, the average length of the urethane fibers was 1.5 mm, the average diameter of the urethane fibers was 50 μm, and the number average molecular weight of the polyurethane constituting the urethane fibers was 60000. The melting point of the polypropylene (Prime Polymer, H700) was 165°C.

[0138] (Examples 2 to 6) A pellet-shaped molding material was prepared in the same manner as in Example 1, except that the types and amounts of raw materials were changed so that the molding material had the composition shown in FIG.

[0139] (Comparative Examples 1 to 7) A pellet-shaped molding material was prepared in the same manner as in Example 1, except that the types and amounts of raw materials were changed so that the molding material had the composition shown in FIG.

[0140] [6] Manufacturing of molded bodies For each of the molding materials in each of the Examples and Comparative Examples, injection molding was performed using an injection molding machine (THX40-5V, manufactured by Nissei Plastics Co., Ltd.) to manufacture a molded body for Charpy impact strength evaluation, a molded body for bending strength evaluation, and a molded body for bending modulus evaluation, which will be described later. The heating temperature of the molding material during injection molding was 180°C. The molded body for Charpy impact strength evaluation was a rectangular plate-shaped molded body with a long side of 80 mm ± 2 mm, a short side of 4.0 mm ± 0.2 mm, and a thickness of 10.0 mm ± 0.2 mm, and the molded body for bending strength evaluation and the molded body for bending modulus evaluation were rectangular plate-shaped molded bodies with a long side of 80 mm ± 2 mm, a short side of 10.0 mm ± 0.2 mm, and a thickness of 4.0 mm ± 0.2 mm.

[0141] [7] Evaluation The molded articles according to the respective Examples and Comparative Examples were evaluated as follows.

[0142] [7-1] Formability For each of the Examples and Comparative Examples, ten molded articles for bending strength evaluation were produced as described in [6] above, and evaluated according to the following criteria: Those that did not meet the conditions of no drooling in the injection molding machine and no burrs, short shots, voids, sink marks, silver streaks, flow marks, warpage, weld lines, cracks, jetting, or discoloration were deemed to be good products, and those that did not meet the conditions were deemed to be defective products.

[0143] A: 10 out of 10 are good products. B: There are 6 to 9 good products out of 10. C: There are 1 to 5 good products out of 10. D: 0 out of 10 are good products.

[0144] [7-2] Charpy impact strength The Charpy impact strength of each of the molded articles for Charpy impact strength evaluation according to each of the Examples and Comparative Examples, which were manufactured as described in [6] above, was measured in accordance with ISO 179 (JIS K7111) using an Impact Tester IT manufactured by Toyo Seiki Seisakusho, Ltd. In measuring the Charpy impact strength, the hammer weight was 4J (WR2.14N / m), the lifting angle was 150°, the notch remaining width was 8.0mm±0.2mm, and the notch angle was 45°.

[0145] [7-3] Bending strength The flexural strength of each of the molded articles for evaluating the flexural strength according to each of the Examples and Comparative Examples, which were produced as described in [6] above, was measured in accordance with ISO 178 (JIS K7171) using an Instron 68TM-30. In measuring the flexural strength, the distance between supporting points was set to 64 mm.

[0146] [7-4] Flexural modulus The molded articles for evaluating the flexural modulus of each of the Examples and Comparative Examples, which were produced as described in [6] above, were subjected to measurement of the flexural modulus in accordance with ISO 178 (JIS K7171) using an Instron 68TM-30. In measuring the flexural modulus, the support distance was set to 64 mm.

[0147] These results are shown together in FIG. 1, together with the compositions and complex viscosities at 180° C. of the molding materials obtained in the respective Examples and Comparative Examples.

[0148] In Fig. 1, the numerical values ​​for the constituent components indicate the content in the molding material, and the unit is mass %. Polypropylene (Prime Polymer, H700, melting point: 165°C) is shown as "polypropylene", and polylactic acid (Unitika, Terramac TE-2000, melting point: 160°C) is shown as "polylactic acid". The complex viscosity shown in Fig. 1 is the value of complex viscosity at 180°C, and is a value obtained by the following measurement. That is, the values ​​were obtained by measuring the sample with a thickness of 1 mm sandwiched between the parallel plates and the lower plate subjected to angular vibration under the following conditions: starting temperature: 100°C, step temperature: 1°C, end temperature: 200°C, heating rate: 5°C / min, strain control: 0.1 deg, frequency: 1 Hz, automatic control: ON, waveform: sine wave, continuous vibration: ON, average number: 3, weight control: OFF, using Pheosol-G3000 (manufactured by UBM). In addition, in the molded bodies of each of the above examples, polyurethane was contained in a state of being compatible with polypropylene or polylactic acid. In other words, the urethane fiber used as the raw material of the molding material was compatible with polypropylene and did not maintain the fibrous state in the molded bodies of each of the above examples. In contrast, the cellulose fiber, acrylic fiber, and polyester fiber used as the raw material of the molding material in the molded bodies of each of the above examples maintained the fibrous state even in the manufactured molded bodies.

[0149] As is clear from Fig. 1, excellent results were obtained in each of the Examples, whereas satisfactory results were not obtained in each of the Comparative Examples.

[0150] In addition, molding materials were produced in the same manner as in each of the above Examples, except that the average length of the cellulose fibers contained in the molding material was changed to 50 μm or more and less than 3 mm, the average diameter of the cellulose fibers was changed to 3 μm or more and less than 100 μm, the average length of the urethane fibers was changed to 50 μm or more and less than 3 mm, the average diameter of the urethane fibers was changed to 3 μm or more and less than 100 μm, and the number average molecular weight of the polyurethane constituting the urethane fibers was changed to 20,000 or more and 300,000 or less. When the same evaluations as above were performed on these materials, the same results as above were obtained.

Claims

1. The present invention includes cellulose fibers, a resin that melts at 200° C. or less, and polyurethane, A molding material having a complex viscosity at 180°C of 3000 Pa·s or more and 147000 Pa·s or less.

2. The molding material according to claim 1 , wherein the resin is at least one selected from the group consisting of polypropylene and polylactic acid.

3. The molding material according to claim 1 , wherein the sum of the content of the resin and the content of the polyurethane is 25.0% by mass or more and 91.0% by mass or less.

4. The molding material according to claim 1 , wherein the average length of the cellulose fibers is 50 μm or more and less than 3 mm.

5. The molding material according to claim 1 , wherein the average diameter of the cellulose fibers is 3 μm or more and less than 100 μm.

6. A molded article made of the molding material according to any one of claims 1 to 5.

7. A method for producing a molded article, comprising molding the molding material according to claim 1 while heating it to a temperature at which the resin melts.

8. The method for producing a molded body according to claim 7, wherein the heating temperature of the molding material is 120°C or higher and 190°C or lower.

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