Molding materials, methods for manufacturing molding materials, molded bodies, and methods for manufacturing molded bodies

Abstract

This invention provides a molding material for manufacturing molded articles and a method for manufacturing the molding material. The molded article comprises polyurethane, is capable of injection molding, exhibits high molding freedom, and possesses excellent impact strength and flexural strength. Furthermore, it provides a molded article comprising polyurethane, exhibiting excellent impact strength and flexural strength, and a method for manufacturing the molded article. The molding material of this invention comprises a polymer blend of organic fibers that do not melt at 200°C and thermoplastic resins that melt below 200°C with thermosetting polyurethane. The content of thermosetting polyurethane in the molding material is preferably 10.0% by mass or more and 40.0% by mass or less.

Description

Technical Field

[0001] This invention relates to molding materials, methods for manufacturing molding materials, molded bodies, and methods for manufacturing molded bodies. Background Technology

[0002] In recent years, social activities aimed at the effective utilization of resources, reduction of waste, and conservation of energy through the reuse of various plastic materials such as polyester have been progressing smoothly.

[0003] Patent Document 1 discloses a wood substitute material for packaging. This wood substitute material is made by heating and compressing a fiber block formed by intertwining 100 parts by weight of recycled fibers and 30-50 parts by weight of thermoplastic resin fibers having a melting point lower than that of the recycled fibers, at a temperature higher than that of the thermoplastic resin fibers but without deterioration of the recycled fibers. The density of this wood substitute material for packaging is 0.4-0.7 g / cm³. 3 .

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2004-025857.

[0007] Polyurethane has excellent elasticity and softness, and is used in various products such as sponges, rubber and other elastic components, and clothing.

[0008] However, polyurethane produces toxic gases (including amine compounds) and odors due to thermal decomposition, making it difficult to reuse. Furthermore, while Patent Document 1 discloses compression molding, using recycled fibers containing polyurethane does not yield molded articles with sufficiently high mechanical strength. Additionally, the technology described in Patent Document 1, when using recycled fibers containing polyurethane, cannot perform injection molding, resulting in limited molding flexibility. Summary of the Invention

[0009] This invention was made to solve the above-mentioned technical problems and can be implemented as the following application examples.

[0010] The molding materials involved in the application examples of the present invention include organic fibers that do not melt at 200°C and polymer blends of thermoplastic resins and thermosetting polyurethanes that melt at below 200°C.

[0011] The manufacturing method of the molding material involved in the application example of the present invention includes a heating and kneading step, wherein the heating and kneading step involves heating and kneading organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethanes in such a way that the thermoplastic resins and the thermosetting polyurethanes melt.

[0012] The molded body in the application examples of the present invention is made of the molding material in the application examples of the present invention.

[0013] The method for manufacturing a molded article according to an application example of the present invention includes a molding step, wherein the molding step is performed while heating the molding material according to the application example of the present invention to the melting temperature of the polymer blend.

[0014] Other application examples of the present invention involve methods for manufacturing molded articles, including: A heating and kneading process involves heating and kneading organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethanes, while simultaneously melting the thermoplastic resins and thermosetting polyurethanes, to obtain a molding material comprising a polymer blend of the organic fibers, the thermoplastic resins, and the thermosetting polyurethanes; and The molding process involves heating the molding material to the melting temperature of the polymer blend while molding. The content of the thermosetting polyurethane in the molding material is 10.0% by mass or more and 40.0% by mass or less. The content of the thermoplastic resin in the molding material is 20.0% by mass or more and 75.0% by mass or less. The organic fiber content in the molding material is 10.0% by mass or more and 55.0% by mass or less. The organic fiber is at least one selected from the group consisting of cellulose fibers and fibers made of thermoplastic resins. The organic fibers are the decomposed components of the fabric. The heating temperature in the heating and kneading process is above 150°C and below 200°C. The heating temperature in the molding process is above 160°C and below 200°C. Attached Figure Description

[0015] Figure 1 This is a table summarizing the composition and evaluation results of the molding materials for each embodiment and comparative example.

[0016] Figure 2This is a photograph showing an image obtained by observing a sample obtained by cutting a 100 μm thick section of the molded body of Comparative Example 3 used for evaluating Charpy impact strength using a digital microscope under transmitted illumination. Detailed Implementation

[0017] The preferred embodiments of the present invention will now be described in detail.

[0018] [1] Molding materials

[0019] First, the molding materials of the present invention will be described.

[0020] The molding material of the present invention comprises organic fibers that do not melt at 200°C and polymer blends of thermoplastic resins that melt below 200°C and thermosetting polyurethanes.

[0021] This configuration provides a molding material containing polyurethane, capable of injection molding, and offering high degree of freedom in molding. Furthermore, it provides a molding material suitable for manufacturing molded articles with excellent mechanical strength, particularly impact strength and flexural strength. Additionally, the flexural modulus of molded articles manufactured using this material is also excellent. Moreover, since the moldability of the molded articles is improved, the productivity of molded articles can also be increased. In particular, by including a resin that melts at temperatures below 200°C, the molding material can be appropriately molded at temperatures that sufficiently prevent the thermal decomposition of polyurethane. Furthermore, although polyurethane is abundant in elastic components such as sponges and rubber, and in waste clothing, it has historically been difficult to reuse due to the generation of toxic gases from thermal decomposition, and incineration is also challenging. However, according to this invention, such polyurethane can be appropriately reused.

[0022] On the other hand, satisfactory results cannot be obtained if the above conditions are not met.

[0023] For example, even if the molding material contains thermoplastic resins and thermosetting polyurethanes that melt below 200°C, if it does not contain organic fibers that do not melt at 200°C, the elastic modulus and shape retention of the molded body made using the molding material will be significantly reduced.

[0024] Furthermore, for example, when inorganic fibers such as carbon fiber (PAN-based carbon fiber (polyacrylonitrile-based carbon fiber)) are used instead of organic fibers that do not melt at 200°C, the affinity with thermoplastic resins or thermosetting polyurethanes that melt below 200°C is reduced, and the mechanical strength of the molded body made using the molding material is reduced.

[0025] Furthermore, even if the molding material contains organic fibers that do not melt at 200°C and thermoplastic resins that melt below 200°C, if it does not contain thermosetting polyurethane, there will be a problem of reduced impact strength of the molded body made using the molding material.

[0026] Furthermore, even if the molding material includes organic fibers that do not melt at 200°C and thermosetting polyurethane, if it does not include thermoplastic resins that melt below 200°C, injection molding will be impossible, and the moldability of the molded article will be significantly reduced. In addition, due to the reduced moldability, the mechanical strength of the manufactured molded article will also be worse.

[0027] Furthermore, when thermoplastic resins with melting points exceeding 200°C are used instead of thermoplastic resins that melt below 200°C for molding materials, the degree of freedom in molding cannot be sufficiently increased; for example, injection molding cannot be performed. In addition, the mechanical strength of molded bodies manufactured using such molding materials also deteriorates.

[0028] Furthermore, even if the molding material contains organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethanes, if the thermoplastic resins and thermosetting polyurethanes that melt below 200°C do not form a polymer blend, the flexural strength and flexural modulus of the molded body made using the molding material will also deteriorate.

[0029] [1-1] Organic fibers that do not melt at 200℃

[0030] The molding material of the present invention contains organic fibers that do not melt at 200°C.

[0031] Organic fibers that do not melt at 200°C are components that greatly contribute to the shape retention of molded articles manufactured using the molding material of the present invention and have a significant impact on properties such as the strength of the molded articles.

[0032] Examples of organic fibers that do not melt at 200°C include cellulose fibers, fibers made of thermoplastic resins, and fibers made of thermosetting resins. However, at least one selected from the group consisting of cellulose fibers and fibers made of thermoplastic resins is preferred, and a combination of cellulose fibers and fibers made of thermoplastic resins is more preferable. This results in molded articles manufactured using molding materials exhibiting superior mechanical strength.

[0033] As an organic fiber that does not melt at 200°C, when including both cellulose fibers and thermoplastic resin fibers, and setting the proportion of the total organic fiber (which does not melt at 200°C) as XC [mass%] and the proportion of the thermoplastic resin fibers as XT [mass%], the following conditions are preferably met: Specifically, it is preferable to satisfy the relationship 0.50 ≤ XC / XT ≤ 2.00, more preferably 0.67 ≤ XC / XT ≤ 1.50, and even more preferably 0.75 ≤ XC / XT ≤ 1.35. This results in molded articles manufactured using molding materials exhibiting superior impact strength and flexural strength.

[0034] Cellulose is an abundant natural raw material derived from plants. Therefore, using cellulose fibers as organic fibers that do not melt at 200°C can appropriately address environmental issues and conserve landfill resources. Furthermore, it is preferred from the perspectives of a stable supply of molding materials and molded articles made using these materials, as well as cost reduction. In addition, cellulose fibers theoretically have particularly high strength among various fibers, which is also advantageous from the viewpoint of improving the strength of molded articles.

[0035] As cellulose fibers, virgin pulp can be used, or waste paper, old cloth, etc., can be reused. Cellulose fibers are usually mainly composed of cellulose, but they can also contain components other than cellulose. Examples of such components include hemicellulose and lignin. In addition, cellulose fibers that have undergone treatments such as bleaching can also be used as cellulose fibers.

[0036] Examples of cellulose fibers include pulp defibers, cotton, linen, rayon, and cuprammonium fiber. For example, a cotton-like defiber obtained by defibering waste paper, such as pulp defiber cotton, can be appropriately used.

[0037] Furthermore, as an organic fiber that does not melt at 200°C, by using fibers made of thermoplastic resin, such as fibers constituting waste clothing, it is possible to appropriately utilize them as organic fibers that do not melt at 200°C, thereby increasing the proportion of waste utilization. From the viewpoint of reducing environmental impact and effectively utilizing resources, this is particularly preferred.

[0038] Examples of thermoplastic resins used to construct fibers include polyester resins, acrylic resins, nylon, and cellulose acetate resins, with polyester resins and acrylic resins being preferred among these. This allows organic fibers that do not melt at 200°C to have better affinity for thermoplastic resins and thermosetting polyurethanes that melt below 200°C, resulting in superior mechanical strength in molded articles made from molding materials. Furthermore, these fibers are widely used as components of clothing, etc. Therefore, by using these fibers as organic fibers that do not melt at 200°C, the utilization rate of waste clothing can be appropriately increased, making them particularly preferred from the viewpoint of reducing environmental impact and effectively utilizing resources.

[0039] Furthermore, since organic fibers do not melt at 200°C, de-fiberized fabric is preferred. This allows for easier recycling of fabrics generated in large quantities as waste clothing, etc. Additionally, carbon fiber or glass fiber textiles typically experience fiber breakage during de-fibering, which is detrimental to improving mechanical strength. Moreover, carbon fiber or glass fiber textiles are primarily used as constituent materials for fiber-reinforced plastics, and extracting and re-fiberizing these materials requires a significant amount of energy. Therefore, it is not appropriate to use inorganic fibers instead of organic fibers that do not melt at 200°C.

[0040] The average length of the organic fibers that do not melt at 200°C 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. This allows for superior shape stability and strength in molded articles manufactured using the molding material. Furthermore, it more effectively prevents and suppresses dust generation in molded articles manufactured using the molding material. Additionally, it more effectively prevents accidental unevenness on the surface of molded articles manufactured using the molding material. The fiber length is determined according to the method in ISO 16065-2:2007.

[0041] The average diameter of the organic fibers that do not melt at 200°C 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. This allows for superior shape stability and strength in molded articles manufactured using the molding material. Furthermore, it more effectively prevents unexpected unevenness from forming on the surface of molded articles manufactured using the molding material.

[0042] The average aspect ratio of the organic fibers that do not melt at 200°C, i.e., the average length relative to the average diameter, is not particularly limited, but is preferably 10 or more and 1000 or less, more preferably 15 or more and 100 or less. This allows for superior shape stability and strength in molded articles manufactured using the molding material. Furthermore, it more effectively prevents and suppresses dust generation in molded articles manufactured using the molding material. Additionally, it more effectively prevents accidental unevenness from forming on the surface of molded articles manufactured using the molding material.

[0043] The content of organic fibers that do not melt at 200°C in the molding material of the present invention is preferably 10.0% by mass or more and 55.0% by mass or less, more preferably 15.0% by mass or more and 50.0% by mass or less, and even more preferably 20.0% by mass or more and 45.0% by mass or less. This allows for a higher balance between the moldability of the molding material and the mechanical strength (particularly impact strength, flexural strength, and flexural modulus) of the molded body manufactured using the molding material.

[0044] [1-2] Thermoplastic resins that melt below 200°C

[0045] The molding material of the present invention includes thermoplastic resins that melt at temperatures below 200°C, i.e. thermoplastic resins with a melting point below 200°C.

[0046] By including a thermoplastic resin that melts at temperatures below 200°C, the toughness of the molded body manufactured using the molding material of the present invention can be improved, and the impact resistance of the molded body can be made sufficiently excellent.

[0047] The melting point of the thermoplastic resin that melts below 200°C is only required to be below 200°C, but preferably above 115°C and below 185°C, and more preferably above 145°C and below 180°C.

[0048] Furthermore, the thermoplastic resin that melts below 200°C is a resin that melts below 200°C on its own, and is also a resin that forms a polymer blend with thermosetting polyurethane below 200°C. Therefore, in molding materials or molded articles, thermoplastic resin and thermosetting polyurethane can exist as polymer blends containing them, resulting in greater freedom of molding the molding materials and superior mechanical strength of the molded articles.

[0049] Examples of thermoplastic resins that melt at temperatures below 200°C include polyolefins such as polyethylene and polypropylene, aliphatic polyesters (polylactic acid, polybutylene succinate, etc.), and aromatic polyesters. One or more of these resins can be used, preferably at least one selected from the group consisting of polypropylene and polylactic acid. This allows for the more appropriate formation of polymer blends of thermoplastic resins that melt at temperatures below 200°C and thermosetting polyurethanes, resulting in more significant effects. In particular, by using thermoplastic resins (such as polylactic acid) derived from biomass feedstocks, the consumption of landfill resources can be more appropriately reduced.

[0050] Furthermore, in this invention, the aforementioned excellent effects are achieved even when using recycled polypropylene. More specifically, recycled polypropylene typically suffers from problems such as reduced molecular weight, decreased viscosity, and reduced moldability due to thermal decomposition during recycling. However, in this invention, excellent injection molding properties are ensured even when using recycled polypropylene.

[0051] Aliphatic polyesters are polyesters with a chemical structure that lacks aromaticity; they are polyesters in which all monomers lack aromaticity. Examples of aliphatic polyesters include those where the polycarboxylic acid and polyol components are both aliphatic alkylene groups. Furthermore, aliphatic polyesters can also be composed of monomers containing both hydroxyl and carboxyl groups within their molecules. Examples of aliphatic polyesters composed of monomers containing both hydroxyl and carboxyl groups within their molecules include polylactic acid.

[0052] When an aliphatic polyester has a chemical structure formed by polymerizing a polycarboxylic acid component with an aliphatic alkylene group and a polyol component with an aliphatic alkylene group, the aliphatic polyester is preferably an aliphatic polyester with a chemical structure formed by the condensation of an alkylene dicarboxylic acid component with an alkylene group having a carbon chain length of 2 or more and 6 or less and an alkylene diol component with an alkylene group having a carbon chain length of 2 or more and 8 or less. This allows for a more suitable formation of polymer blends between thermoplastic resins that melt at temperatures below 200°C and thermosetting polyurethanes, resulting in a more significant improvement over the aforementioned effects.

[0053] The alkylene dicarboxylic acid has an alkylene group with a carbon chain length of 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 more significantly enhances the aforementioned effects.

[0054] The alkylene dicarboxylic acid may have a branched structure, but is preferably a straight-chain alkylene dicarboxylic acid. This allows for a more significant achievement of the aforementioned effects.

[0055] Examples of alkylene dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, etc., and one or more of them may be used.

[0056] The alkylene glycol preferably has an alkylene group with a carbon chain length of 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 more significantly enhances the aforementioned effects.

[0057] The alkylene glycol may have a branched structure, but is preferably a straight-chain alkylene glycol. This allows for a more significant achievement of the aforementioned effects.

[0058] Examples of alkylene glycols include 1,2-ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol, and one or more of these may be used.

[0059] As specific examples of aliphatic polyesters containing alkylene dicarboxylic acids and alkylene diols as monomeric components that meet the above conditions, examples include polybutylene succinate, polybutylene succinate / adipate, and polyethylene adipate, etc., and one or more of them may be used.

[0060] These are biodegradable materials, which can more appropriately reduce the environmental impact caused by molded articles. Furthermore, these materials are relatively inexpensive and readily available. Therefore, they are advantageous from the perspective of a stable supply of molding materials or molded articles, and cost reduction.

[0061] The content of the thermoplastic resin that melts at 200°C or below in the molding material of the present invention is not particularly limited, but is preferably 20.0% by mass or more and 75.0% by mass or less, more preferably 20.0% by mass or more and 70.0% by mass or less, and even more preferably 20.0% by mass or more and 60.0% by mass or less. This allows for a higher balance between the moldability of the molding material and the mechanical strength (particularly impact strength, flexural strength, and flexural modulus) of the molded body manufactured using the molding material.

[0062] When the content of the thermoplastic resin that melts below 200°C in the molding material of the present invention is defined as XR [mass%], and the content of the organic fiber that does not melt at 200°C is defined as XO [mass%], it is preferable to satisfy the relationship 0.03 ≤ XO / XR ≤ 3.0, more preferably to satisfy the relationship 0.10 ≤ XO / XR ≤ 2.8, and even more preferably to satisfy the relationship 0.50 ≤ XO / XR ≤ 2.5. This results in molded articles manufactured using the molding material exhibiting superior impact strength and flexural strength.

[0063] [1-3] Thermosetting polyurethane

[0064] The molding material of the present invention includes thermosetting polyurethane. The thermosetting polyurethane referred to herein is polyurethane in its cured state, excluding prepolymers and other uncured polyurethane.

[0065] Thermosetting polyurethanes are typically components that exhibit excellent affinity with either organic fibers that do not melt at 200°C or thermoplastic resins that melt below 200°C.

[0066] As a thermosetting polyurethane, thermosetting polyurethane foam, thermosetting polyurethane rubber, etc. can be used, for example.

[0067] Thermosetting polyurethane exhibits excellent affinity with the aforementioned thermoplastic resins that melt at temperatures below 200°C, allowing for the appropriate formation of polymer blends between them. This enables the improvement of the flexural strength and other properties of molded articles manufactured using the molding material of the present invention.

[0068] The number average molecular weight of the thermosetting 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. This makes the thermosetting polyurethane more compatible with organic fibers that do not melt at 200°C or with thermoplastic resins that melt below 200°C, resulting in superior impact strength and flexural strength in molded articles made using the molding material.

[0069] The content of thermosetting polyurethane in the molding material of the present invention is preferably 10.0% by mass or more and 40.0% by mass or less. As a result, the moldability of the molding material and the mechanical strength (especially impact strength, flexural strength and flexural modulus) of the molded body manufactured using the molding material can be balanced at a higher level.

[0070] The sum of the content of the thermoplastic resin that melts at 200°C and the content of the thermosetting polyurethane in the molding material of the present invention is preferably 30.0% by mass or more and 90.0% by mass or less. As a result, the moldability of the molding material and the mechanical strength (especially impact strength, flexural strength and flexural modulus) of the molded body manufactured using the molding material can be balanced at a higher level.

[0071] When the content of the thermoplastic resin that melts below 200°C in the molding material of the present invention is set as XR [mass%], and the content of the thermosetting polyurethane is set as XU [mass%], it is preferable to satisfy the relationship 0.01≤XU / XR≤0.30, more preferably 0.02≤XU / XR≤0.20, and even more preferably 0.03≤XU / XR≤0.10. This allows for a higher balance between the moldability of the molding material and the mechanical strength (particularly impact strength, flexural strength, and flexural modulus) of the molded body manufactured using the molding material.

[0072] When the content of the organic fiber that does not melt at 200°C in the molding material of the present invention is set as XC [mass%], and the content of the thermosetting polyurethane is set as XU [mass%], it is preferable to satisfy the relationship 0.01≤XU / XC≤3.0, more preferably to satisfy the relationship 0.02≤XU / XC≤1.6, and even more preferably to satisfy the relationship 0.03≤XU / XC≤0.6. Therefore, it is possible to achieve a higher level of balance between the moldability of the molding material and the mechanical strength (especially impact strength, flexural strength, and flexural modulus) of the molded body manufactured using the molding material.

[0073] [1-4] Flame retardants

[0074] The molding material of the present invention may also contain a flame retardant.

[0075] Examples of flame retardants include inorganic flame retardants such as antimony compounds, metal hydroxides, nitrogen compounds, and boron compounds, as well as organic flame retardants such as bromine compounds and phosphorus compounds.

[0076] When the molding material contains a flame retardant, and the total content of organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethane is set to 100.0 parts by weight, the content of the flame retardant can be 1.0 parts by weight or more and 20.0 parts by weight or less. This allows for more effective application of the effects of the present invention and results in molded articles manufactured using the molding material of the present invention exhibiting superior flame retardancy.

[0077] [1-5] Other ingredients

[0078] The molding material of the present invention may also contain components other than those described above. Hereinafter, such components will also be referred to as "other components" within this scope. Examples of other components include colorants, insect repellents, mildew inhibitors, antioxidants, ultraviolet absorbers, agglomeration inhibitors, release agents, and resin materials other than those described above. 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.

[0079] [1-6] Other

[0080] As described above, the molding material of the present invention comprises organic fibers that do not melt at 200°C and a polymer blend of a thermoplastic resin and a thermosetting polyurethane that melts below 200°C. In other words, at least a portion of the thermoplastic resin and thermosetting polyurethane that melt below 200°C included in the molding material of the present invention constitutes a polymer blend. For the thermoplastic resin and thermosetting polyurethane that melt below 200°C, as long as at least a portion of them constitutes a polymer blend, the other portions may not constitute a polymer blend. More specifically, the thermoplastic resin that melts below 200°C included in the molding material of the present invention may have a portion that constitutes a polymer blend with the thermosetting polyurethane, while the other portions do not constitute a polymer blend, or it may be entirely constitute a polymer blend. Furthermore, the thermosetting polyurethane included in the molding material of the present invention may have a portion that constitutes a polymer blend with the thermoplastic resin that melts below 200°C, while the other portions do not constitute a polymer blend, or it may be entirely constitute a polymer blend.

[0081] In particular, the molding material of the present invention preferably has an island structure in which islands composed of a material comprising a polymer blend of a thermoplastic resin molten at 200°C and a thermosetting polyurethane are dispersed within a sea portion composed of a thermoplastic resin molten at 200°C and a sea portion. This improves impact resistance by concentrating stress in the thermosetting polyurethane that forms the islands. Whether such an island structure is present can be determined by the following analysis: physical property analysis is performed to confirm the presence of components with a folded modulus of 100 MPa or less. If such components are present, it can be determined that the island portion is composed of a material comprising a polymer blend of a thermoplastic resin molten at 200°C and a thermosetting polyurethane. Specifically, for example, a cross-section of the molding material or molded body is measured in contact mode using a Park Systems Japan NX20 scanning probe microscope to obtain an observation image. This allows determination of the presence of components with a folded modulus of 100 MPa within the island portion. Furthermore, a known nanoindenter can be used to confirm the island structure.

[0082] When the molding material of the present invention has an island structure, the size of the islands is not particularly limited, but the average particle size of the islands is preferably 300 μm or less, more preferably 1 μm or more and 100 μm or less, and even more preferably 1 μm or more and 10 μm or less. This allows for superior mechanical strength in the molded articles manufactured using the molding material. Furthermore, in this specification, average particle size refers to the average particle size based on volume.

[0083] [2] Manufacturing method of molding material

[0084] Next, the manufacturing method of the molding material of the present invention will be described.

[0085] The method for manufacturing the molding material of the present invention includes a heating and kneading step, in which organic fibers that do not melt at 200°C, thermoplastic resins that melt at below 200°C, and thermosetting polyurethanes are kneaded while being heated to melt the thermoplastic resin (i.e., the thermoplastic resin that melts at below 200°C) and the thermosetting polyurethane. With this configuration, the molding material of the present invention as described above can be efficiently manufactured. Furthermore, it is known that thermosetting polyurethanes with a chemically cross-linked structure, in addition to having a very high cross-linking density, at least partially melt when heated. In the heating and kneading step, this molten portion constitutes a polymer blend with the thermoplastic resin that melts at below 200°C.

[0086] In the heating and kneading process, a single-shaft kneading machine or a twin-shaft kneading machine can be used, for example.

[0087] In the manufacture of the molding material of the present invention, the thermosetting polyurethane used as a raw material is preferably in particulate form, and in particular, the average particle size is preferably 2000 μm or less, more preferably 50 μm or more and 1500 μm or less, and even more preferably 50 μm or more and 150 μm or less. This allows for the appropriate formation of the aforementioned island structure, resulting in superior mechanical strength of the molded body manufactured using the molding material.

[0088] The heating temperature in the heating and kneading process is preferably 150°C or higher and 200°C or lower, more preferably 160°C or higher and 195°C or lower, and even more preferably 170°C or higher and 190°C or lower. This allows for more appropriate hydrolysis and plasticization of a portion of the thermosetting polyurethane, enabling the formation of a polymer blend of thermoplastic resin and thermosetting polyurethane that melts at temperatures below 200°C. In particular, it allows for the formation of the aforementioned island-shaped structure, resulting in a more significant achievement of the aforementioned effects.

[0089] The filamentous molding material obtained by mixing and kneading can also be pelletized using a pelletizer with a filament method or a water ring hot cutting method to produce granular molding material.

[0090] Furthermore, the following method can also be applied as a manufacturing method for molding materials. That is, the mixture of the above components can be molded into sheets, and then, for example, cut into desired shapes using a paper shredder to produce granular molding materials. The method for molding the mixture into sheets is not particularly limited; for example, the following method can be used: first, the mixture is piled in air to form a sheet-like pile; the pile is compressed using a calendering device to remove air and increase density; then, it is heated non-contactly in a furnace; and finally, it is heated and pressurized using a hot press. The shape and size of the granules obtained by cutting are not particularly limited; for example, a sheet can be a roughly rectangular prism with a length of 2 mm or more and 5 mm or less.

[0091] The organic fibers used in the manufacture of the molding material of the present invention, which do not melt at 200°C, can also be organic fibers that have undergone pre-defibering treatment. In particular, organic fibers obtained by defibering organic fiber sources containing organic fibers, such as waste paper and old cloth, can also be used.

[0092] Furthermore, in the case where the molding material of the present invention comprises fibrous thermosetting polyurethane, i.e. thermosetting urethane fiber, the thermosetting urethane fiber used in the manufacture of the molding material may also be urethane fiber that has undergone pre-defiber treatment.

[0093] Furthermore, the aforementioned fiber source can also be coarsely shredded before defiberization. Coarse shredding of the fiber source can be achieved, for example, by using a paper shredder with coarse blades in an atmosphere such as air to produce fine flakes. The shape of the flakes can be, for example, a roughly cubic or roughly rectangular shape, a few millimeters square. The fine flakes of the fiber source are then defiberized into unwound fibers. Defiberization, as referred to here, means separating multiple fibers from a single, unified state, one fiber at a time.

[0094] Fiber debonding can be appropriately carried out under dry conditions. Here, "dry" means carried out not in a liquid, but in a gaseous environment such as the atmosphere. Additionally, to prevent electrostatic charging, the fibers can be sprayed with water, for example. Dry fiber debonding can also be appropriately carried out using airflow, for example.

[0095] The defiberization of the fiber source can be carried out separately in each fiber source or in a mixture of multiple fiber sources.

[0096] In addition, fiber sources containing multiple fibers can also be used as fiber sources. Examples of fiber sources containing two or more fibers include blended fabrics.

[0097] The defiberization of the fiber source can also be carried out in a state containing components other than fibers, such as thermoplastic resins that melt below 200°C, non-fibrous thermosetting polyurethanes, flame retardants, and other components.

[0098] [3] Molded body

[0099] Next, the molded body of the present invention will be described.

[0100] The molded body of the present invention is a molded body made of the molding material described above. This configuration provides a molded body that excels in both polyurethane properties and mechanical strength, particularly impact strength and flexural strength. Furthermore, the flexural modulus of elasticity of the molded body is also excellent. While polyurethane is widely found in elastic components such as sponges and rubber, and in waste clothing, it has historically been difficult to reuse due to the generation of toxic gases during heat treatment, and incineration is also challenging. However, according to the present invention, such polyurethane can be appropriately reused.

[0101] Furthermore, the molded body of the present invention may have portions made of the molding material of the present invention as described above, or portions made of materials other than the molding material of the present invention.

[0102] The components constituting the molded article preferably satisfy the conditions described in [1-1] to [1-6] above.

[0103] The shape of the molded object is not particularly limited; for example, it can be any shape such as sheet, block, sphere, or three-dimensional.

[0104] The molded body can be for any purpose and can be appropriately applied to molded bodies used in environments where dust generation is a problem. More specifically, it can be used for components with fluid flow paths or components disposed around such components, ink cartridges, various containers, and various everyday utensils. Conventional molded bodies manufactured using materials containing fibrous materials and resins are prone to dust generation and are unsuitable for use in environments where dust generation is a problem. In contrast, the molded body according to the present invention is less prone to dust generation. Therefore, the effects of the present invention are more significantly enhanced when applied to such applications.

[0105] [4] Manufacturing method of molded body

[0106] Next, the method for manufacturing the molded article of the present invention will be described.

[0107] The method for manufacturing a molded article according to the present invention includes a molding step in which molding is performed while heating the molding material of the present invention to the melting temperature of the polymer blend contained in the molding material (i.e., a polymer blend of a thermoplastic resin and a thermosetting polyurethane that melts at temperatures below 200°C). Therefore, a method for manufacturing a molded article can be provided that produces a molded article with excellent polyurethane properties, mechanical strength, particularly impact strength, and flexural strength. Furthermore, the flexural modulus of the manufactured molded article is also excellent.

[0108] As a molding method, compression molding, extrusion molding, etc. can be used, but injection molding is preferred. As a result, even molded bodies with complex structures or molded bodies with fine structures can be manufactured appropriately.

[0109] The heating temperature of the molding material in the molding process is preferably 160°C or higher and 200°C or lower, more preferably 170°C or higher and 190°C or lower. This allows for better prevention of thermal decomposition of polyurethane while improving moldability and the productivity of the molded article. Furthermore, it results in superior mechanical strength of the manufactured molded article.

[0110] The method for manufacturing the molded article of the present invention may also include processes other than the molding process. For example, it may include post-processing processes such as grinding / sharpening, painting, plating, etc., performed after the molding process.

[0111] As described above, the method for manufacturing the molded article of the present invention can be any method having the following molding steps: the molding step involves heating the molding material of the present invention to the melting temperature of the polymer blend contained in the molding material (i.e., a polymer blend of thermoplastic resin and thermosetting polyurethane that melts at 200°C) while molding, but preferably includes: a heating and kneading step in which organic fibers that do not melt at 200°C, thermoplastic resin and thermosetting polyurethane that melt at 200°C are heated and kneaded while melting the thermoplastic resin and the thermosetting polyurethane to obtain a molding material containing the organic fibers and the polymer blend of the thermoplastic resin and the thermosetting polyurethane; and a molding step in which... The molding process involves heating the molding material to the melting temperature of the polymer blend while molding, wherein the content of the thermosetting polyurethane in the molding material is 10.0% by mass or more and 40.0% by mass or less, the content of the thermoplastic resin in the molding material is 20.0% by mass or more and 75.0% by mass or less, and the content of the organic fiber in the molding material is 10.0% by mass or more and 55.0% by mass or less. The organic fiber is at least one selected from the group consisting of cellulose fibers and fibers made of thermoplastic resins, and the organic fiber is a desiccant of fabric. The heating temperature in the heating and kneading process is 150°C or more and 200°C or less, and the heating temperature in the molding process is 160°C or more and 200°C or less. Thus, the synergistic effect of the aforementioned factors results in particularly excellent performance.

[0112] The preferred embodiments of the present invention have been described above, but the present invention is not limited thereto.

[0113] For example, the molding material of the present invention may be any polymer blend of organic fibers that do not melt at 200°C and thermoplastic resins that melt at below 200°C and thermosetting polyurethanes, and is not limited to molding materials manufactured by the methods described above.

[0114] Furthermore, the molded body of the present invention can be made of the molding material of the present invention, and is not limited to a molded body manufactured by the method described above.

[0115] Example

[0116] Next, specific embodiments of the present invention will be described.

[0117] [5] Preparation of raw materials for molding materials

[0118] First, prepare waste paper containing cellulose fibers, recycled clothing containing rayon, recycled clothing containing acrylic fibers, recycled clothing containing polyester fibers, and Multi POLYMAX Belt manufactured by Mitsuboshi Belting Co., Ltd. containing thermosetting urethane rubber.

[0119] Next, the waste paper and clothing recyclables from various markets are shredded into roughly cubic shapes (a few millimeters square) in the atmosphere using a paper shredder with coarse blades, and then de-fibered by blowing air. This yields pulp de-fiber cotton, rayon, and acrylic fibers, which are organic fibers that do not melt at 200°C.

[0120] On the other hand, for the thermosetting urethane rubber, a pulverizing process was performed using a pulverizer with inner and outer blades, thereby breaking it into particles with an average particle size of 100 μm. Thus, a thermosetting urethane rubber as a thermosetting polyurethane was obtained.

[0121] In addition, as thermoplastic resins that melt below 200°C, commercially available polypropylene (manufactured by Prime Polymer, H700) and commercially available thermoplastic polyurethane (manufactured by Nisshinbo Textile Co., Ltd., Mobilon Tape MW-1003T) are prepared. Polypropylene has a melting point of 165°C. Thermoplastic polyurethane has a melting point of 150°C.

[0122] [6] Preparation of molding materials

[0123] Example 1

[0124] The following heated kneading process is performed: Pulp defiber cotton (an organic fiber that does not melt at 200°C), polypropylene (a thermoplastic resin that melts below 200°C), and thermosetting polyurethane rubber (with a particle size of 0.1 mm or less) are added in a predetermined ratio to a biaxial mixer (manufactured by Technovel, KZW15TW-45MG) for kneading. The kneading conditions are: a maximum heating temperature of 170°C and an extrusion discharge rate of 1 kg / hr. After being processed into filaments, the material is pelletized into granules for molding using a pelletizer. The resulting molding material has an island structure: islands composed of a polymer blend of thermoplastic resin (melting below 200°C) and thermosetting polyurethane are dispersed within a sea composed of thermoplastic resin (melting below 200°C). The average particle size of the islands in this island structure is 20 μm. Furthermore, the average length of the cellulose fibers included in the molding material, which are organic fibers that do not melt at 200°C, is 700 μm, and the average diameter of the cellulose fibers, which are organic fibers that do not melt at 200°C, is 15 μm.

[0125] Examples 2-4

[0126] In addition to changing the type and amount of raw materials used to make the composition of molding materials as Figure 1 Apart from the composition shown, granular molding materials are prepared in the same manner as in Example 1.

[0127] In all the molding materials of the embodiments described above, there is an island structure in which islands composed of a polymer blend of a thermoplastic resin that melts at 200°C and a thermosetting polyurethane are dispersed within a sea composed of a thermoplastic resin that melts at 200°C. The average particle size of the islands in this island structure is in the range of 1 μm or more and 300 μm or less. Furthermore, in the molding materials of the embodiments described above, the average length of the organic fibers that do not melt at 200°C is in the range of 100 μm or more and less than 400 μm, the average diameter is in the range of 5 μm or more and less than 20 μm, and the average aspect ratio is in the range of 15 or more and 100 or less, thus maintaining the fiber shape. Furthermore, the number average molecular weight of the thermosetting polyurethane contained in the molding materials of the embodiments is in the range of 40,000 or more and 150,000 or less.

[0128] Comparative Examples 1-4

[0129] In addition to changing the type and amount of raw materials used to make the composition of molding materials as Figure 1 Apart from the composition shown, granular molding materials are prepared in the same manner as in Example 1.

[0130] [7] Manufacturing of molded parts

[0131] For each molding material used in the embodiments and comparative examples, injection molding was performed using an injection molding machine (manufactured by Nissei Resin Kogyo Co., Ltd., THX40-5V) to attempt to manufacture molded bodies for Charpy impact strength evaluation, flexural strength evaluation, and flexural modulus evaluation, as described later. The heating temperature of the molding material during injection molding was 170°C. The molded body for Charpy impact strength evaluation was a rectangular plate-shaped body with a long side of 80mm ± 2mm, a short side of 4.0mm ± 0.2mm, and a thickness of 10.0mm ± 0.2mm. The molded bodies for flexural strength evaluation and flexural modulus evaluation were also rectangular plate-shaped bodies with a long side of 80mm ± 2mm, a short side of 10.0mm ± 0.2mm, and a thickness of 4.0mm ± 0.2mm.

[0132] [8] Evaluation

[0133] The molded articles involved in the various embodiments and comparative examples are evaluated as follows.

[0134] [8-1] Formability

[0135] For each of the embodiments and comparative examples, as described above [7], the 10 molded bodies for evaluating bending strength were evaluated according to the following criteria. In addition, molded bodies that meet the conditions of not leaking (running) in the injection molding machine and having no burrs, underfill, voids, shrinkage marks, silver streaks, flow marks, warpage, weld lines, cracks, spray marks, or scorching in the molded body were considered qualified products, and molded bodies that did not meet the conditions were considered unqualified products.

[0136] A: 10 out of 10 products are qualified.

[0137] B: Qualified products are 6 to 9 out of 10.

[0138] C: Qualified products are 1 to 5 out of 10.

[0139] D: 0 out of 10 products are qualified.

[0140] [8-2] Charpy impact strength

[0141] For the molded bodies used for Charpy impact strength evaluation in the embodiments and comparative examples described above [7], the Charpy impact strength was determined using an impact testing machine IT manufactured by Toyo Seiki Co., Ltd., in accordance with ISO 179 (JIS K7111). In the Charpy impact strength determination, the hammer weight was set to 4J (WR2.14N / m), the lift angle was set to 150°, the notch residual width was set to 8.0mm±0.2mm, and the notch angle was set to 45°.

[0142] [8-3] Flexural modulus

[0143] For the molded bodies used for evaluating the flexural modulus of elasticity in the embodiments and comparative examples manufactured as described above [7], the flexural modulus of elasticity was determined according to ISO 178 (JIS K7171) using an Instron 68TM-30. In the determination of the flexural modulus of elasticity, the distance between the support points was set to 64 mm.

[0144] [8-4] Bending strength

[0145] For the molded bodies used for evaluating bending strength in the embodiments and comparative examples manufactured as described above [7], the bending strength was measured according to ISO 178 (JIS K7171) using an Instron 68TM-30. In the measurement of bending strength, the distance between the support points was set to 64 mm.

[0146] [8-5] Overall Evaluation

[0147] Based on the results of [8-1] to [8-3] above, the embodiments and comparative examples are comprehensively evaluated according to the following criteria.

[0148] A: The evaluation for [8-1] above is A, and the evaluation for [8-2] above is 2.3 kJ / m 2 The above, and the evaluation in [8-3] above, is 1.5 GPa or higher.

[0149] B: The evaluation in [8-1] above is A, and the evaluation in [8-2] above is less than 2.3 kJ / m 2 Or, as evaluated in [8-3] above, less than 1.5 GPa.

[0150] C: The evaluation of [8-1] above is B.

[0151] D: The evaluation of [8-1] above is C.

[0152] These results, together with the compositions of the molding materials obtained in the various embodiments and comparative examples, are presented in the following figures. Figure 1 .

[0153] in addition, Figure 1 In this text, the numerical values ​​for the constituent components represent the content in the molding material, and the unit is mass%. Furthermore, polypropylene (manufactured by Prime Polymer, H-700, melting point: 165°C) is referred to as "polypropylene," and thermoplastic polyurethane (manufactured by Nisshinbo Textile Co., Ltd., Mobilon Tape MW-1003T, melting point: 150°C) is referred to as "thermoplastic polyurethane." Moreover, in the molded articles of each embodiment, there is an island structure in which islands composed of a polymer blend of thermoplastic resin and thermosetting polyurethane molten at 200°C are dispersed within a sea composed of thermoplastic resin molten at 200°C, and the average particle size of the islands in this island structure is in the range of 1 μm or more and 300 μm or less. Furthermore, in the molded articles of the various embodiments, the average length of the organic fibers that do not melt at 200°C is in the range of 100 μm or more and less than 400 μm, the average diameter is in the range of 5 μm or more and less than 20 μm, and the average aspect ratio is in the range of 15 or more and less than 100, thus maintaining the shape of the fibers. Furthermore, the number average molecular weight of the thermosetting polyurethane included in the molded articles of the various embodiments is in the range of 40,000 or more and less than 150,000.

[0154] also, Figure 2This is a photograph showing an image obtained by observing a sample obtained by cutting a 100 μm thick section of the molded body of Comparative Example 3 used for Charpy impact strength evaluation using a digital microscope under transmitted illumination. A Keyence VHX-5000 digital microscope was used as the digital microscope.

[0155] from Figure 1 It is evident that excellent results were obtained in the aforementioned embodiments. In contrast, satisfactory results were not obtained in the aforementioned comparative examples. Furthermore, as... Figure 2 As shown, the molded body of Comparative Example 3 has an island structure as follows: islands composed of a material comprising a polymer blend of a thermoplastic resin molten at below 200°C and a thermosetting polyurethane are dispersed within a sea composed of a thermoplastic resin molten at below 200°C. Furthermore, the molded body of the embodiment also has the same structure.

[0156] Furthermore, various modifications are made to the molding material to ensure that the content of non-melting organic fibers at 200°C is 10.0% by mass or more and 55.0% by mass or less, the content of thermosetting polyurethane is 10.0% by mass or more and 40.0% by mass or less, and the content of thermoplastic resin is 20.0% by mass or more and 75.0% by mass or less, so that the average length of the non-melting organic fibers at 200°C in the molding material is 50 μm or more and less than 3 mm, and the average length of the non-melting organic fibers at 200°C is... Various modifications were made to the following: the diameter of the organic fibers was 3 μm or more and less than 100 μm; the average aspect ratio of the organic fibers that do not melt at 200°C was 10 or more and less than 1000; the number average molecular weight of the thermosetting polyurethane was 20,000 or more and less than 300,000; and the heating temperature in the heat-mixing process was varied within the range of 150°C or more and less than 200°C. Except for these modifications, molding materials were manufactured in the same manner as in the above embodiments, and the same results were obtained when they were evaluated as described above. Furthermore, if, for the above embodiments, molding bodies were manufactured in the same manner as described above, except that the heating temperature in the molding process for manufacturing the molding body was varied within the range of 160°C or more and less than 200°C, and the same results were obtained when they were evaluated as described above, the same results were obtained. Furthermore, if the average particle size of the thermosetting polyurethane used as a raw material is varied to be between 50 μm and 2000 μm, and the average particle size of the island portion of the island structure included in the molding material is varied to be between 1 μm and 300 μm, and the molding material is manufactured in the same manner as in the above embodiments, and is evaluated in the same manner as described above, the same results as described above are obtained.

Claims

1. A molding material, The molding material comprises organic fibers that do not melt at 200°C and a polymer blend of thermoplastic resin and thermosetting polyurethane that melts below 200°C.

2. The molding material according to claim 1, wherein, The content of the thermosetting polyurethane is 10.0% by mass or more and 40.0% by mass or less.

3. The molding material according to claim 1, wherein, The content of the thermoplastic resin is 20.0% by mass or more and 75.0% by mass or less.

4. The molding material according to claim 1, wherein, The content of the organic fiber is 10.0% by mass or more and 55.0% by mass or less.

5. The molding material according to claim 1, wherein, The organic fiber is selected from at least one of the group consisting of cellulose fibers and fibers made of thermoplastic resins.

6. The molding material according to claim 1, wherein, The organic fibers are the desiccant of the fabric.

7. A method for manufacturing a molding material, The method for manufacturing the molding material includes a heating and kneading step, wherein the heating and kneading step involves heating and kneading organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethanes in a manner that melts the thermoplastic resins and the thermosetting polyurethanes.

8. The method for manufacturing the molding material according to claim 7, wherein, The heating temperature in the heating and kneading process is above 150°C and below 200°C.

9. A molded body, The molded body is made of the molding material according to any one of claims 1 to 6.

10. A method for manufacturing a molded object, The method for manufacturing the molded article includes a molding step, wherein the molding step is performed while heating the molding material according to any one of claims 1 to 6 to the melting temperature of the polymer blend.

11. The method for manufacturing a molded article according to claim 10, wherein, The heating temperature in the molding process is above 160°C and below 200°C.

12. A method for manufacturing a molded article, comprising: A heating and kneading process involves heating and kneading organic fibers that do not melt at 200°C, thermoplastic resins that melt below 200°C, and thermosetting polyurethanes, while simultaneously melting the thermoplastic resins and thermosetting polyurethanes, to obtain a molding material comprising a polymer blend of the organic fibers, the thermoplastic resins, and the thermosetting polyurethanes; and The molding process involves heating the molding material to the melting temperature of the polymer blend while molding. The content of the thermosetting polyurethane in the molding material is 10.0% by mass or more and 40.0% by mass or less. The content of the thermoplastic resin in the molding material is 20.0% by mass or more and 75.0% by mass or less. The organic fiber content in the molding material is 10.0% by mass or more and 55.0% by mass or less. The organic fiber is at least one selected from the group consisting of cellulose fibers and fibers made of thermoplastic resins. The organic fibers are the decomposed components of the fabric. The heating temperature in the heating and kneading process is above 150°C and below 200°C. The heating temperature in the molding process is above 160°C and below 200°C.

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