Molded body and manufacturing method thereof, kneaded body and manufacturing method thereof, and polishing body and manufacturing method thereof

Abstract

To provide a method for manufacturing a molded body useful for manufacturing a polyvinyl chloride-containing product having sufficiently high coefficient of elasticity.SOLUTION: A method for manufacturing a molded boy in the present disclosure includes the steps of: (A) obtaining a kneaded matter by kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, and at lease one kind of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber and nylon 66 fiber under temperature conditions of 141-280°C; and (B) molding the kneaded matter into a molded body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a molded body and a method for manufacturing the same, a method for manufacturing a kneaded material, and an abrasive body and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a method for producing a composite recycled sheet using polyvinyl chloride resin as part of the raw materials. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-82802 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional methods have not been able to produce polyvinyl chloride-containing products with a sufficiently high elastic modulus from polyvinyl chloride resin. The present disclosure aims to solve the above problem. [Means for solving the problem]

[0005] A method for producing a molded article according to one aspect of the present disclosure includes the following steps. (A) A step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber at a temperature of 141 to 280°C to obtain a kneaded product. (B) A step of processing the kneaded mixture into a molded product.

[0006] A molded article according to one aspect of the present disclosure comprises a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, and at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber, and satisfies at least one of a tensile modulus of elasticity of 21 MPa or more and a compressive modulus of elasticity of 8 MPa or more.

[0007] A method for producing a kneaded product according to one aspect of the present disclosure includes a step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber at a temperature of 141 to 280°C.

[0008] A method for manufacturing an abrasive body according to one aspect of the present disclosure includes the following steps. (A1) A step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber, and an abrasive under a temperature condition of 141 to 280°C to obtain a kneaded product. (B1) A step of forming the kneaded material into an abrasive body.

[0009] The method for producing an abrasive body may be as follows. That is, the method for producing an abrasive body may include: (A2) a step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers at a temperature of 141 to 280°C to obtain a kneaded mixture; and (B2) a step of molding the kneaded mixture into an abrasive body, wherein the content of the fibers in the kneaded mixture is 10 to 80 mass% based on the mass of the kneaded mixture. Alternatively, the method for producing an abrasive body may include: (A3) a step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with an abrasive at a temperature of 141 to 280°C to obtain a kneaded mixture; and (B3) a step of molding the kneaded mixture into an abrasive body, wherein the content of the abrasive in the kneaded mixture is 5 to 80 mass% based on the mass of the kneaded mixture. Furthermore, the method for producing an abrasive body may include the steps of (A4) kneading a matrix resin composition containing at least a polyvinyl chloride resin, at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber, and an abrasive at a temperature of 141 to 280°C to obtain a kneaded mixture, and (B4) molding the kneaded mixture into an abrasive body.

[0010] An abrasive body according to one aspect of the present disclosure includes a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber, and an abrasive.

[0011] The polishing body may be in the following form. That is, the polishing body may contain a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, and at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers, with the fiber content being 10 to 80 mass% (based on the total mass of the polishing body). Alternatively, the polishing body may contain a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, and an abrasive, with the abrasive content being 5 to 80 mass% (based on the total mass of the polishing body). Furthermore, the polishing body may contain a matrix resin composition containing at least a polyvinyl chloride resin, at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers, and an abrasive. [Effects of the Invention]

[0012] The present disclosure provides a molded body useful for producing polyvinyl chloride-containing products having a sufficiently high elastic modulus, a method for producing the same, and a method for producing a kneaded product. The present disclosure also provides an abrasive body, which is one embodiment of the molded body, and a method for producing the same. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of a tile carpet. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an example of a molded article according to the present disclosure. [Figure 3] 3(a) and 3(b) are scanning electron microscope images of the fibers contained in the molded article according to Example 1. FIG. [Figure 4] 4(a) and 4(b) are scanning electron microscope images of the sample of the molded article of Example 3 after the polyvinyl chloride resin and plasticizer were extracted and removed. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In the following embodiments, a molded article containing polypropylene fibers is produced as an example. However, nylon fibers (at least one of nylon 6 fibers and nylon 66 fibers) may be included instead of the polypropylene fibers, or both polypropylene fibers and nylon fibers (at least one of nylon 6 fibers and nylon 66 fibers) may be included.

[0015] The method for producing a molded article according to this embodiment includes the following steps. (A) A step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with polypropylene fibers at a temperature of 141 to 280°C to obtain a kneaded mixture. (B) A step of processing the kneaded mixture into a molded product. Here, polyvinyl chloride resin is a resin synthesized by addition polymerization of vinyl chloride monomer (CH═CHCl). Polyvinyl chloride resin is hard by itself, but it becomes soft by adding a plasticizer to polyvinyl chloride resin. Compositions containing polyvinyl chloride resin and a plasticizer are used, for example, in tile carpets, flexible films, hoses, and automotive interior and exterior components.

[0016] According to the above-described production method, a molded article having a sufficiently high elastic modulus can be produced by passing through step (A). For example, when the kneading temperature in step (A) is 141 to 169°C, this temperature is close to the melting point of the polypropylene fibers. Therefore, in the molded article produced through step (B), the polypropylene fibers have intertwined points where the polypropylene fibers are thermally fused together. It is presumed that these polypropylene fibers function as a reinforcing material (see FIGS. 3(a) and 3(b)). On the other hand, when the kneading temperature in step (A) is higher than 170°C but not higher than 280°C, the polypropylene fibers melt. In particular, when the polypropylene in the polypropylene fibers is not acid-modified or has low compatibility with other resins such as nylon, it is presumed that polypropylene aggregates are mixed into the kneaded product. Therefore, the molded article produced from this kneaded product has a high elastic modulus. The kneading temperature may be 201 to 220°C, 221 to 245°C, 246 to 265°C, or 266 to 280°C.

[0017] By keeping the kneading temperature at 200°C or less, thermal degradation of the polyvinyl chloride resin can be suppressed. When suppressing thermal degradation of the polyvinyl chloride resin is particularly important, the kneading temperature is preferably 169°C or less. On the other hand, when a high elastic modulus of the molded product to be produced is particularly important, the kneading temperature is preferably 170°C to 200°C. Note that the kneading temperature here refers to the set temperature of the kneading device, and it is estimated that the temperature of the kneaded product is about 1 to 20°C higher than the set temperature. This temperature difference is due to shear heat generated by kneading.

[0018] The polypropylene fiber material may be a polypropylene homopolymer (melting point: about 170°C) or a copolymer of propylene and other monomers (e.g., ethylene). The melting point of polypropylene fibers varies depending on the degree of polymerization and crystallinity of the polypropylene, and the type and content of other monomers. In order to determine the temperature range in which polypropylene fibers are thermally fused to each other at the intertwining points, a test may be conducted in which the polypropylene fibers are repeatedly heated under multiple temperature conditions.

[0019] This embodiment will be described below using an example in which a molded article (e.g., a sheet, film, tube, cup, or block) is manufactured from a carpet tile. The carpet tile 10 shown in FIG. 1 includes a pile layer 1 made of pile yarns and a base layer 3 in which some of the pile yarns are embedded. The base layer 3 in this embodiment has a two-layer structure and is composed of an intermediate layer 3a in contact with the pile layer 1 and a base layer 3b. The intermediate layer 3a has a thickness of, for example, 0.1 to 5 mm. The base layer 3b has a thickness of, for example, 1 to 10 mm. The base layer 3 has a thickness (total thickness of the intermediate layer 3a and the base layer 3b) of, for example, 1.1 to 15 mm. The carpet tile 10 may be scrap material generated during the manufacturing process or used material disposed of by an ordinary household or office.

[0020] The pile layer 1 is composed of pile yarns made of a fibrous material. In this embodiment, the pile yarns are made of polypropylene fibers. The pile layer 1 may also contain other synthetic fibers or natural fibers. Examples of synthetic fibers include polyester fibers, nylon fibers, and acrylic fibers. Examples of natural fibers include linen, cotton, and wool. The pile layer 1 is formed, for example, by warp pile weaving or weft pile weaving. The pile layer 1 may be formed, for example, by implanting pile yarns using a tufting machine, or by bonding the pile yarns using an adhesive. The pile configuration may be either cut pile or loop pile.

[0021] The intermediate layer 3a is sandwiched between the pile layer 1 and the base layer 3b. Some of the pile yarns are embedded in the intermediate layer 3a, and it serves to fix the pile layer 1 and bond the pile layer 1 to the base layer 3b. The intermediate layer 3a is made of a composition containing polyvinyl chloride resin, a plasticizer, and a filler, and contains resin fibers (e.g., PET fibers). The plasticizer is used to impart flexibility to the polyvinyl chloride resin. The filler is used, for example, to improve the dimensional stability of the tile carpet 10. The resin fibers are used to bind the pile yarns of the pile layer 1 together.

[0022] Examples of plasticizers include dioctyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), di-2-ethylhexyl adipate (DOA), diisononyl adipate (DINA), tri-2-ethylhexyl trimellitate (TOTM), and tricresyl phosphate (TCP).

[0023] Examples of fillers include calcium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, magnesium hydroxide, aluminum hydroxide, and glass powder. Of these, calcium carbonate is preferred from the standpoints of economy and processability.

[0024] The base layer 3b forms the back surface of the tile carpet 10. The base layer 3b is made of a composition containing polyvinyl chloride resin and a plasticizer. The plasticizer may be the same as that contained in the intermediate layer 3a. The base layer 3b may or may not contain the above-mentioned filler.

[0025] When tile carpets are used as at least part of the raw material for the molded body, step (a1) of crushing tile carpets 10 may be carried out before step (A). In this case, crushed tile carpets 10 as a whole may be used as at least part of the matrix resin composition. Crushed base layer 3 may also be used as at least part of the matrix resin composition. When the pile yarns contain polypropylene fibers, crushed pile yarns may also be used as at least part of the polypropylene fibers in step (A).

[0026] In step (a1), the tile carpet 10 is crushed to prepare the raw material for the kneaded material. The tile carpet 10 may be crushed using a known crushing device. A known crushing device may be used to pulverize the tile carpet 10 into powder. It is preferable to crush the tile carpet 10 with an intensity and processing time that results in a particle size of 10 mm or less (excluding crushed pile yarns). The particle size of the crushed material is more preferably 5 mm or less, and even more preferably 2 mm or less. A particle size of 2 mm or less of the crushed material tends to result in a uniform kneaded material in a relatively short processing time in step (A). The lower limit of the particle size of the crushed material is, for example, 0.1 mm. A particle size of 0.1 mm or more of the crushed material tends to prevent the crushed material from becoming excessively bulky and reducing handleability. The particle size of the crushed material can be determined by preparing multiple sieves with different mesh sizes and determining whether the crushed material passes through the sieves.

[0027] The entire raw material of the kneaded material may be crushed tile carpet 10, or a portion of the raw material of the kneaded material may be crushed tile carpet and used in combination with other materials. Examples of other materials include polyvinyl chloride resin and polypropylene fibers not derived from tile carpet. The amount of polyvinyl chloride resin to be used may be determined depending on the intended use and desired performance of the molded product. From the perspective of effective use of tile carpet 10, the amount of crushed tile carpet 10 used per 100 parts by mass of the raw material of the kneaded material is preferably 50 parts by mass or more, more preferably 80 parts by mass or more.

[0028] It is preferable that at least a portion of the polypropylene fibers have a length of 2 mm or more (more preferably 3 to 8 mm). This allows the reinforcing effect of the polypropylene fibers to be even more pronounced. Polypropylene fibers not derived from the tile carpet 10 may be used, for example, when the length of the crushed pile yarns is excessively short. Note that, to prevent the polypropylene fibers constituting the pile yarns from becoming excessively short due to crushing, the pile layer 1 and the base layer 3 may be separated before crushing the tile carpet 10, and the pile layer 1 may be crushed under different conditions than those for the base layer 3, as necessary.

[0029] The content of polypropylene fibers in the kneaded product is preferably 5 to 95 parts by mass, more preferably 10 to 90 parts by mass, and may be 10 to 40 parts by mass or 40 to 70 parts by mass, relative to 100 parts by mass of the total mass of the kneaded product. When the content of polypropylene fibers is within the above range, a molded product having a high elastic modulus can be produced from the kneaded product.

[0030] In step (B), the kneaded mixture is processed into a molded product. Sheet- or film-shaped molded products can be produced by known plastic sheet molding methods such as the calendar method or T-die method. Cylindrical molded products (e.g., tubes) can be produced by known plastic molding methods such as extruders, blow molding machines, or injection molding machines. Blocks having a predetermined shape can be produced using a mold or extruder. When producing a sheet-shaped molded product (e.g., 0.1 to 10 mm thick), it is preferable to complete the molded product by pressing the sheet during production under predetermined temperature and pressure conditions. The pressing temperature is preferably the same as the kneading temperature (141 to 280°C), and is preferably 141 to 169°C to suppress thermal degradation of the polyvinyl chloride resin. To obtain a molded product with a high elastic modulus, it is preferably 170 to 200°C, or may be 200 to 280°C. The pressing pressure is preferably 5 to 30 MPa, more preferably 10 to 20 MPa. Furthermore, parts with irregular shapes such as cups, bats, and bowls can be manufactured by known plastic molding methods such as injection molding machines and press molding machines.

[0031] A pressing temperature of 200°C or less can suppress thermal degradation of the polyvinyl chloride resin. When suppressing thermal degradation of the polyvinyl chloride resin is particularly important, the pressing temperature is preferably 169°C or less. On the other hand, when a high elastic modulus of the molded product is particularly important, the pressing temperature is preferably 170°C or more.

[0032] 2 is a cross-sectional view schematically showing an example of a sheet-like molded product manufactured through a pressing process. The sheet-like molded product 20 is composed of a matrix resin composition 5 and polypropylene fibers 7. The polypropylene fibers 7 are contained in a state in which there are intertwined points where the polypropylene fibers 7 are thermally fused together. Due to the reinforcing effect of the polypropylene fibers 7, the sheet-like molded product 20 has a sufficiently high elastic modulus.

[0033] The molded article satisfies at least one of a tensile modulus of 21 MPa or more and a compressive modulus of 8 MPa or more. The tensile modulus of the molded article is preferably 21 MPa or more, more preferably 180 MPa or more, even more preferably 270 MPa or more, and even more preferably 330 MPa or more. The modulus of elasticity referred to here can be determined by cutting a test piece of a predetermined size (e.g., 120 mm long x 10 mm wide) from the molded article and subjecting this test piece to a tensile test. The tensile test is performed under conditions of an atmosphere of 23°C and 50% RH, with a chuck distance of 50 mm and a tensile speed of 50 mm / min, and the modulus of elasticity is calculated when the strain is between 0.0005 and 0.0025. The compressive modulus of the molded article is preferably 8 MPa or more, more preferably 170 MPa or more, even more preferably 210 MPa or more, and even more preferably 380 MPa or more. The elastic modulus referred to here is the elastic modulus calculated from the region of the stress-strain curve where the stress and strain are linearly related when a compression test is performed on a molded body having a diameter of 28 mm and a thickness of 21 mm under conditions of 23°C, 50% RH, and a compression rate of 5 mm / min.

[0034] As described above, the method for producing a molded article according to this embodiment allows for the production of a molded article having a sufficiently high elastic modulus from the tile carpet 10. By using offcuts generated during the manufacturing process or used carpets discarded by ordinary households or offices as the tile carpet 10, these materials, which have traditionally been disposed of primarily in landfills, can be effectively utilized. According to the above embodiment, a kneaded product can be obtained in which thermal degradation is sufficiently suppressed. Therefore, according to this embodiment, a recycling efficiency of, for example, 70% or more can be achieved. The recycling efficiency here refers to the ratio of the mass of waste (e.g., discarded carpet tiles) to the total mass of the waste and virgin materials when producing a molded article. From the perspective of effective waste utilization, the recycling efficiency is preferably 80% or more, more preferably 90% or more, and even more preferably 100%.

[0035] An example of a molded body that uses waste (e.g., discarded tile carpet) as at least a portion of the raw material is an abrasive body. The abrasive body contains a matrix resin composition containing at least polyvinyl chloride resin and a plasticizer, at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber, and an abrasive. A kneaded material for the abrasive body may be prepared in the same manner as described above, except that an abrasive is added to the kneaded material. The shape of the abrasive body may be, for example, a disk, disc, or rod. A disk-shaped or disc-shaped abrasive body can be attached to a disc grinder for use. The diameter of the disk-shaped or disc-shaped abrasive body is, for example, 3 to 300 mm, and the thickness is, for example, 1 to 200 mm. A rod-shaped abrasive body can be used as a handheld type.

[0036] The abrasive is, for example, an inorganic material, specific examples of which include calcium carbonate particles, alumina particles, and diamond particles. It is presumed that the polyvinyl chloride resin acts as an adhesive, and the polyvinyl chloride resin and fibers (nylon fibers and / or polypropylene fibers) act as a cushion. This prevents the abrasive from causing deeper scratches than necessary on the object to be polished. The abrasive content of the polishing body is, for example, 5 to 80 mass%, preferably 10 to 70 mass%, and more preferably 30 to 60 mass%. The fiber content of the polishing body is, for example, 10 to 80 mass%, preferably 10 to 70 mass%, and more preferably 20 to 60 mass%. The fiber referred to here is at least one type of fiber selected from the group consisting of polypropylene fiber, nylon 6 fiber, and nylon 66 fiber.

[0037] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above embodiments. For example, although the above embodiments illustrate tile carpets having a two-layer base layer, the base layer may be a single layer or a laminated structure of three or more layers.

[0038] In the above embodiment, the pile yarn is made of polypropylene fiber, and other polypropylene fibers are used in combination as needed. However, if the pile yarn is made of a fiber other than polypropylene fiber (for example, at least one of nylon 6 fiber and nylon 66 fiber), a kneaded material can be prepared by blending polypropylene fiber with crushed tile carpet material.

[0039] In the above embodiment, an example was given of a case where a molded article was produced from a tile carpet, but the molded article may be produced from a product containing polyvinyl chloride resin (e.g., a flexible film, a tube, and an automobile interior / exterior component) without being limited to a tile carpet.

[0040] In the above embodiment, the case of producing a molded article containing polypropylene fibers has been exemplified. However, nylon fibers (at least one of nylon 6 fibers and nylon 66 fibers) may be used instead of polypropylene fibers, or both polypropylene fibers and nylon fibers (at least one of nylon 6 fibers and nylon 66 fibers) may be used. The content of nylon fibers in the kneaded product is preferably 6 to 80 parts by mass, more preferably 20 to 70 parts by mass, or may be 20 to 50 parts by mass or 50 to 70 parts by mass, relative to 100 parts by mass of the total mass of the kneaded product. When the content of nylon fibers is within the above range, a molded article having a high elastic modulus can be produced from the kneaded product. The total amount of fibers in the kneaded product is preferably 10 to 95 parts by mass, more preferably 20 to 80 parts by mass, or may be 20 to 60 parts by mass or 30 to 70 parts by mass, relative to 100 parts by mass of the total mass of the kneaded product. When the content of nylon fibers is within the above range, a molded article having a high elastic modulus can be produced from the kneaded product.

[0041] When kneading is performed at a temperature close to the melting point of the nylon fiber, the nylon fibers are thermally fused together at intertwined points within the molded product, and it is believed that these nylon fibers function as a reinforcing material. On the other hand, when kneading is performed at a temperature sufficiently higher than the melting point of the nylon fiber, the nylon fibers melt, and if the resin other than nylon has low compatibility with nylon, it is believed that nylon aggregates become mixed into the kneaded product. As a result, molded products produced from this kneaded product have a high elastic modulus.

[0042] In the above embodiment, one embodiment of the abrasive body is exemplified as comprising a matrix resin composition containing at least polyvinyl chloride resin and a plasticizer, at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers, and an abrasive. However, the abrasive body does not necessarily contain an abrasive. That is, the abrasive body may comprise a matrix resin composition containing at least polyvinyl chloride resin and a plasticizer, and at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers. The fiber content in this abrasive body is, for example, 10 to 80 mass %, preferably 10 to 70 mass %, and more preferably 20 to 60 mass %. This abrasive body can be produced by a step (A2) of kneading a matrix resin composition containing at least polyvinyl chloride resin and a plasticizer with at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers at a temperature of 141 to 280°C to obtain a kneaded mixture.

[0043] The abrasive body includes an abrasive and a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, and may not contain at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers. The abrasive content in this abrasive body is, for example, 5 to 80 mass %, preferably 10 to 70 mass %, and more preferably 30 to 60 mass %. This abrasive body can be produced by (A3) kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with the abrasive at a temperature of 141 to 280°C to obtain a kneaded mixture, and (B3) molding the kneaded mixture into the abrasive body.

[0044] The abrasive body comprises a matrix resin composition containing at least polyvinyl chloride resin, at least one type of fiber selected from the group consisting of polypropylene fibers, nylon 6 fibers, and nylon 66 fibers, and an abrasive, but may not contain a plasticizer. The fiber content in this abrasive body is, for example, 10 to 80 mass%, preferably 10 to 70 mass%, and more preferably 20 to 60 mass%. The abrasive content in this abrasive body is, for example, 5 to 80 mass%, preferably 10 to 70 mass%, and more preferably 30 to 60 mass%. This abrasive body can be produced by (A4) kneading a matrix resin composition containing at least polyvinyl chloride resin and an abrasive at a temperature of 141 to 280°C to obtain a kneaded mixture, and (B4) molding the kneaded mixture into an abrasive body. A matrix resin that is substantially free of plasticizer can be obtained from ground tile carpet that contains polyvinyl chloride resin and plasticizer, for example, by contacting the ground tile carpet with a solvent and dissolving the plasticizer in the solvent, or by heating the ground tile carpet to a temperature higher than the volatilization temperature of the plasticizer to volatilize the plasticizer.

[0045] The molded article of the present invention can be used for, for example, automobile parts, electric and electronic parts, consumer goods, construction materials, medical materials, radiation shielding materials, agricultural materials, fishery materials, and tools, but is preferably used for automobile parts.Furthermore, since a filler is often used, it can be suitably used for sound insulation materials, vibration damping materials, and sliding members. [Example]

[0046] The present disclosure will be described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0047] In order to produce recycled polyvinyl chloride resin, the following tile carpets were prepared. <Carpet tiles> Layer structure: pile layer / intermediate layer (base layer) / base material layer (base layer) · Tile carpet composition Polyvinyl chloride resin (PVC): 100 parts by mass Plasticizer (dioctyl phthalate, DOP): 100 parts by mass Nylon fiber (C): 120 parts by mass PET fiber: 47 parts by mass Calcium carbonate (CaCO3): 300 parts by mass

[0048] <Ingredient preparation> (Crushed carpet tile A) Ground carpet tiles (particle size: approximately 0.1 to 4 mm) were prepared. (Polypropylene fiber B) Polypropylene fibers were prepared by cutting at least a portion of the fibers constituting the pile layer of a tile carpet manufactured by Suminoe Textile Co., Ltd. (model number: PX-3000) to a length of 2 mm or more. The diameter of the polypropylene fibers was approximately 20 μm. (Nylon fiber C) Nylon fiber (diameter: 20-50 μm, length: approximately 4 mm) recovered from a crushed waste carpet tile was used. The composition of nylon fiber C was 100 parts by mass of nylon 6 fiber and 100 parts by mass of nylon 66 fiber. (Polyvinyl chloride resin pulverized material D) Ground material (particle size: approximately 0.1 to 4 mm) of the base layer of a tile carpet was prepared. The composition of the ground polyvinyl chloride resin D was 100 parts by mass of polyvinyl chloride, 100 parts by mass of a plasticizer (dioctyl phthalate, DOP), and 300 parts by mass of calcium carbonate. (Nylon fiber E) Nylon fibers were prepared by cutting at least a portion of the fibers constituting the pile layer of a tile carpet (model number: GA-100) manufactured by Toli into lengths of 2 mm or more. (Polyvinyl chloride resin crushed material F) Polyvinyl chloride resin pulverized material F was prepared by removing the plasticizer from polyvinyl chloride resin pulverized material D. The composition of polyvinyl chloride resin pulverized material F was 100 parts by mass of polyvinyl chloride and 300 parts by mass of calcium carbonate. (Polyvinyl chloride resin G) Polyvinyl chloride resin (product code: 223-00255) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was prepared.

[0049] <Production of Sheet-Like Molded Product> Example 1 A mixture containing 45 g of ground material A (90 parts by mass) and polypropylene fiber B (10 parts by mass) was prepared. The mixture was kneaded for 5 minutes in a batch mixer at a set temperature of 141°C. This batch mixer had two blades (diameter: 30 mm) configured to rotate in opposite directions. The rotation speed of one blade was 60 rpm, and the rotation speed of the other blade was 90 rpm. The resulting kneaded mixture was pressed at a temperature of 157°C and a pressure of 5 MPa to obtain a sheet-like molded product with a thickness of approximately 1 mm. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, thermal fusion between fibers was confirmed in some of the fibers.

[0050] Example 2 A sheet-like molded product (thickness: approximately 1 mm) was obtained in the same manner as in Example 1, except that the pressing temperature was set to 169°C. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, thermal fusion between fibers was confirmed in some of the fibers.

[0051] Example 3 A sheet-like molded product (thickness: about 1 mm) was obtained in the same manner as in Example 1, except that the kneading temperature and the pressing temperature were both set to 200° C. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, the fibers were found to exist independently, and no thermal fusion between the fibers was confirmed.

[0052] Example 4 A sheet-like molded product (thickness: about 1 mm) was obtained in the same manner as in Example 1, except that 40 g of pulverized material A (80 parts by mass) and polypropylene fiber B (20 parts by mass) were kneaded together.

[0053] Example 5 A sheet-like molded product (thickness: approximately 1 mm) was obtained in the same manner as in Example 3, except that a mixture of 45 g of pulverized material A (90 parts by mass) and nylon fiber C (10 parts by mass) was used as the raw material. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, the fibers were found to be present independently, and no thermal fusion between the fibers was confirmed.

[0054] Example 6 A sheet-like molded product (thickness: approximately 1 mm) was obtained in the same manner as in Example 3, except that a mixture of 40 g of pulverized material A (80 parts by mass) and nylon fiber C (20 parts by mass) was used as the raw material.

[0055] Example 7 A sheet-like molded product (thickness: approximately 1 mm) was obtained in the same manner as in Example 1, except that no fibers (polypropylene fiber B and nylon fiber C) were added and only pulverized material A (50 g) was used as the raw material. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, the fibers were found to be present independently, and no thermal fusion between the fibers was confirmed.

[0056] Example 8 A sheet-like molded product (thickness: approximately 1 mm) was obtained in the same manner as in Example 3, except that no fibers (polypropylene fiber B and nylon fiber C) were added and only pulverized material A (50 g) was used as the raw material. When the cross section of the sheet-like molded product was observed using a scanning electron microscope, the fibers were found to be present alone and no thermal fusion between the fibers was confirmed.

[0057] (Comparative Example 1) A sheet-shaped molding (thickness: approximately 1 mm) was obtained in the same manner as in Example 3, except that pulverized material A and fibers (polypropylene fiber B and nylon fiber C) were not blended and only polyvinyl chloride resin pulverized material D (50 g) was used as the raw material.

[0058] <Evaluation of elastic modulus> Test specimens were prepared by punching out multiple test specimens from each of the sheet-like molded articles of the Examples and Comparative Examples. The test specimens were 120 mm long and 10 mm wide. Tensile tests were performed on the test specimens in an atmosphere of 23°C and 50% RH, with a chuck distance of 50 mm and a tensile speed of 50 mm / min. Three tensile tests were performed on each Example and Comparative Example. The tensile modulus was calculated for strains between 0.0005 and 0.0025. The results are shown in Table 1.

[0059] [Table 1]

[0060] <Observation of fiber structure in kneaded material> The kneaded material prepared in Example 1 was cut into pieces several millimeters square, and the polyvinyl chloride resin and plasticizer were extracted and removed using tetrahydrofuran (THF) as a solvent. The pieces were then dried to obtain a sample. The fibers and calcium carbonate separated from the sample, and the sample did not retain its original shape after cutting. Observation of the sample using a scanning electron microscope confirmed the presence of fibers (see Figures 3(a) and 3(b)). Thermal fusion between fibers was confirmed in some of the fibers. Elemental analysis of the fused fiber portions was performed using an energy dispersive X-ray spectrometer (EDS) attached to the scanning electron microscope, and no N derived from nylon was detected. This confirmed that the fused fibers were polypropylene fibers.

[0061] The kneaded material prepared in Example 3 was cut into pieces several millimeters square, and the polyvinyl chloride resin and plasticizer were extracted and removed using tetrahydrofuran (THF) as a solvent. The resulting sample was then dried to obtain a sample. The fibers and calcium carbonate did not easily separate from the sample, and the sample maintained its original shape after cutting. Observation of the sample using a scanning electron microscope confirmed the presence of fibers and aggregates presumably formed by melting the fibers (see Figures 4(a) and 4(b)). No thermal fusion between the fibers was observed. Elemental analysis of the fibers and aggregates using an energy dispersive X-ray spectrometer (EDS) attached to the scanning electron microscope confirmed the presence of N derived from nylon fibers in the fibers, but not in the aggregates. This confirmed that the fibers were nylon and that the aggregates were formed by melting polypropylene fibers.

[0062] <Production of block molded body> Example 9 A block molded body was manufactured from the kneaded material prepared in the same manner as in Example 1. That is, the kneaded material obtained in the same manner as in Example 1 was pressed under conditions of a temperature of 157°C and a pressure of 15 MPa to obtain a disk-shaped molded body (block molded body) having a diameter of 28 mm and a thickness of 21 mm.

[0063] Example 10 A disk-shaped molded product was obtained in the same manner as in Example 9, except that a mixture of 45 g of pulverized material A (90 parts by mass) and nylon fiber C (10 parts by mass) was used as the raw material.

[0064] Example 11 A disk-shaped molded body was obtained in the same manner as in Example 9, except that the kneading temperature was set to 200°C and the pressing temperature was also set to 200°C.

[0065] Example 12 A disk-shaped molded body was obtained in the same manner as in Example 10, except that the kneading temperature was 200°C and the pressing temperature was also 200°C.

[0066] Example 13 A disk-shaped molded product was obtained in the same manner as in Example 11, except that no fibers (polypropylene fiber B and nylon fiber C) were added and only pulverized material A (50 g) was used as the raw material.

[0067] (Comparative Example 2) A disk-shaped molded body was obtained in the same manner as in Example 11, except that pulverized material A and fibers (polypropylene fiber B and nylon fiber C) were not blended, and only polyvinyl chloride resin pulverized material D (50 g) was used as the raw material.

[0068] <Evaluation of elastic modulus> A compression test was carried out on each of the disk-shaped molded articles according to the above Examples and Comparative Examples in an atmosphere of 23°C, 50% RH, and a compression speed of 5 mm / min. The compressive modulus of elasticity was obtained in the region where the stress and strain were linearly related in the obtained stress-strain diagram. The results are shown in Table 2.

[0069] [Table 2]

[0070] <Manufacturing recycled abrasives> In addition to the above-mentioned pulverized material A, the following raw materials were prepared. Calcium carbonate particles: Hayashi Pure Chemical Industries (particle size: 2.2 μm) Alumina particles: Naniwa Polishing Industry (400 grit)

[0071] (Examples 14A and 15A) Kneaded materials were prepared with the compositions shown in Table 3. The kneading temperature was 200° C. Each kneaded material was pressed at a temperature of 200° C. and a pressure of 15 MPa to obtain recycled abrasive bodies (diameter 28 mm, thickness 21 mm) according to Examples 14A and 15A.

[0072] The resulting polishing body was inserted into a 6 mm diameter drill and brought into contact with a stainless steel plate and a copper plate while rotating with an electric driver drill. A 10 mm square frame was marked on each of the stainless steel plate and the copper plate with a pen, and the time required to polish the area within the frame was measured. The end point was the time when the gloss of the area within the frame disappeared. The polishing performance was evaluated based on the following criteria. As a result, the polishing performance shown in Table 3 was confirmed for stainless steel plate and copper plate. A: Polishing was completed in a short time (1 to 20 seconds). B: It took longer to polish than A (21 to 60 seconds). C: It took even longer to polish than B (61-90 seconds). D: Almost no polishing was possible (even after 91 seconds or more, no polishing was possible).

[0073] [Table 3]

[0074] As described below, recycled abrasive bodies measuring 10 mm in diameter and 20 mm in thickness were prepared, and their polishing performance was evaluated. The resulting abrasive bodies were inserted into a 3.5 mm diameter drill and brought into contact with a stainless steel plate and a copper plate while rotating with an electric driver drill. A 10 mm square frame was marked on each of the stainless steel plate and the copper plate in advance with a pen, and the time required to polish the area within the frame was measured. The end point was the time when the gloss of the area within the frame disappeared. The polishing performance was evaluated based on the following criteria. As a result, the polishing performance shown in Tables 4 and 5 was confirmed for stainless steel plate and copper plate. A: Polishing was completed in a short time (1 to 20 seconds). B: It took longer to polish than A (21 to 60 seconds). C: It took even longer to polish than B (61-90 seconds). D: Almost no polishing was possible (even after 91 seconds or more, no polishing was possible).

[0075] The "surface hardness" shown in Tables 4 and 5 was measured using a durometer hardness tester (type D) in accordance with JIS K 7215. For each example and comparative example, the test was carried out three times, and the surface hardness was calculated from the average value. The "moldability" shown in Tables 4 and 5 was evaluated based on the following criteria. A: Can be molded with a good appearance B: Can be molded, but moldability is inferior to A C: Cannot be molded The results are shown in Tables 4 and 5.

[0076] Example 14B A recycled abrasive body was obtained in the same manner as in Example 14A, except that the recycled abrasive body was 10 mm in diameter and 20 mm in thickness instead of 28 mm in diameter and 21 mm in thickness.

[0077] Example 15B A recycled abrasive body was obtained in the same manner as in Example 15A, except that the recycled abrasive body was 10 mm in diameter and 20 mm in thickness instead of 28 mm in diameter and 21 mm in thickness.

[0078] (Comparative Example 3) Polyvinyl chloride resin pulverized material D (100 parts by mass) was kneaded at a temperature of 200°C. As in Example 1, a batch kneader having two blades was used for kneading, with one blade rotating at 60 rpm and the other at 90 rpm. The kneading time was 5 minutes. The kneaded material was pressed at a temperature of 200°C and a pressure of 15 MPa to obtain a cycle abrasive body (diameter 10 mm, thickness 20 mm).

[0079] Example 16 A mixture of ground material A (67 parts by mass) and nylon fiber C (33 parts by mass) was kneaded at a temperature of 200°C. As in Example 1, a batch kneader with two blades was used for kneading, with one blade rotating at 60 rpm and the other at 90 rpm. The kneading time was 5 minutes. The kneaded product was pressed at a temperature of 200°C and a pressure of 15 MPa to obtain a cycle-polished body (diameter 10 mm, thickness 20 mm).

[0080] Example 17 A mixture of polyvinyl chloride resin pulverized material D (70 parts by mass) and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded product was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0081] Example 18 A mixture of pulverized material A (47 parts by mass), nylon fiber C (23 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0082] Example 19 A mixture of pulverized material A (28 parts by mass), nylon fiber C (42 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0083] Example 20 A mixture of ground material A (9 parts by mass), nylon fiber C (61 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0084] Example 21 A mixture of pulverized material A (50 parts by mass) and alumina particles (50 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0085] Example 22 A mixture of polyvinyl chloride resin pulverized material D (90 parts by mass) and alumina particles (10 parts by mass) was kneaded at a temperature of 200° C. The kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa, and the same procedure as in Example 16 was repeated to obtain a recycled abrasive body (diameter 10 mm, thickness 20 mm).

[0086] Example 23 A mixture of pulverized material A (90 parts by mass) and alumina particles (10 parts by mass) was kneaded at a temperature of 200° C. The kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa, and the same procedure as in Example 16 was repeated to obtain a recycled abrasive body (diameter 10 mm, thickness 20 mm).

[0087] Example 24 A mixture of pulverized material A (60 parts by mass), nylon fiber C (30 parts by mass), and alumina particles (10 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0088] Example 25 A mixture of polyvinyl chloride resin pulverized material D (95 parts by mass) and alumina particles (5 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded product was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0089] Example 26 A mixture of pulverized material A (95 parts by mass) and alumina particles (5 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0090] Example 27 A mixture of pulverized material A (63 parts by mass), nylon fiber C (32 parts by mass), and alumina particles (5 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0091] Example 28 A mixture of pulverized material A (47 parts by mass), nylon fiber C (23 parts by mass), and calcium carbonate particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0092] Example 29 A mixture of pulverized material A (70 parts by mass) and alumina particles (30 parts by mass) was kneaded at a temperature of 141° C. The kneaded mixture was pressed at a temperature of 157° C. and a pressure of 15 MPa, and the same procedure as in Example 16 was repeated to obtain a recycled abrasive body (diameter 10 mm, thickness 20 mm).

[0093] Example 30 A mixture of pulverized material A (70 parts by mass) and alumina particles (30 parts by mass) was kneaded at a temperature of 141° C. The kneaded mixture was pressed at a temperature of 169° C. and a pressure of 15 MPa, and the same procedure as in Example 16 was repeated to obtain a recycled abrasive body (diameter 10 mm, thickness 20 mm).

[0094] Example 31 A mixture of pulverized material A (40 parts by mass), calcium carbonate (30 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0095] Example 32 A mixture of polyvinyl chloride resin pulverized material D (52 parts by mass), nylon fiber E (18 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0096] Example 33 A mixture of pulverized polyvinyl chloride resin D (35 parts by mass), nylon fiber E (35 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0097] Example 34 A mixture of polyvinyl chloride resin pulverized material D (52 parts by mass), nylon fiber C (18 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0098] Example 35 A mixture of polyvinyl chloride resin pulverized material D (35 parts by mass), nylon fiber C (35 parts by mass), and alumina particles (30 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0099] Example 36 A mixture of pulverized polyvinyl chloride resin F (25 parts by mass), nylon fiber C (25 parts by mass), and alumina particles (50 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded mixture was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0100] Example 37 A mixture of polyvinyl chloride resin G (25 parts by mass), nylon fiber C (25 parts by mass), and alumina particles (50 parts by mass) was kneaded at a temperature of 200° C. A recycled abrasive body (diameter 10 mm, thickness 20 mm) was obtained in the same manner as in Example 16, except that the resulting kneaded product was pressed at a temperature of 200° C. and a pressure of 15 MPa.

[0101] [Table 4]

[0102] [Table 5] [Explanation of symbols]

[0103] 1...pile layer, 3...base layer, 3a...intermediate layer, 3b...base material layer, 5...matrix resin, 7...polypropylene fiber (fiber), 10...tile carpet, 20...sheet-shaped molded body

Claims

1. (A) a step of kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with fibers under a temperature condition of 141 to 169°C to obtain a kneaded mixture; (B) processing the kneaded mixture into a molded body; Including, the fibers comprise polypropylene fibers; The method for producing a molded body, wherein the polypropylene fibers in the molded body have intertwining points where the polypropylene fibers are thermally fused together.

2. A method for producing a molded body as described in claim 1, wherein the fibers further include at least one type selected from the group consisting of nylon 6 fibers and nylon 66 fibers.

3. The method for producing a molded article according to claim 1 or 2, wherein at least a part of the polypropylene fibers before kneading in step (A) has a length of 2 mm or more.

4. (A) Before the step, (a1) crushing a carpet having a pile layer made of pile yarns and a base layer in which some of the pile yarns are embedded and which contains at least a polyvinyl chloride resin and a plasticizer; The method for producing a molded article according to any one of claims 1 to 3, wherein at least a part of the matrix resin composition in step (A) is crushed material of the carpet.

5. The method for producing a molded article according to claim 4, wherein the carpet is a tile carpet.

6. The method for producing a molded article according to claim 5, wherein the tile carpet is a discarded tile carpet.

7. the pile yarns comprise polypropylene fibers; The method for producing a molded article according to any one of claims 4 to 6, wherein at least a part of the polypropylene fibers in step (A) are crushed pile yarns.

8. A method for producing a molded body described in any one of claims 4 to 7, wherein the pile yarn further contains at least one type selected from the group consisting of nylon 6 fiber and nylon 66 fiber.

9. a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer; Fiber and A molded body comprising: the fibers comprise polypropylene fibers; The polypropylene fibers in the molded body have intertwining points where the polypropylene fibers are thermally fused together.

10. A molded body as described in claim 9, having a tensile modulus of elasticity of 21 MPa or more.

11. A molded body as described in claim 9 or 10, having a compressive modulus of elasticity of 8 MPa or more.

12. A process for obtaining a kneaded product by kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer, fibers, and an abrasive under a temperature condition of 141 to 169°C; forming the kneaded material into an abrasive body; Including, the fibers comprise polypropylene fibers; The method for manufacturing an abrasive body, wherein the polypropylene fibers in the abrasive body have intertwining points where the polypropylene fibers are thermally fused together.

13. A process for producing a kneaded product by kneading a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer with fibers under a temperature condition of 141 to 169°C; forming the kneaded material into an abrasive body; Including, the content of the fibers in the kneaded material is 10 to 80 mass% based on the mass of the kneaded material, the fibers comprise polypropylene fibers; The method for manufacturing an abrasive body, wherein the polypropylene fibers in the abrasive body have intertwining points where the polypropylene fibers are thermally fused together.

14. A process for obtaining a kneaded product by kneading a matrix resin composition containing at least a polyvinyl chloride resin, fibers, and an abrasive under a temperature condition of 141 to 169°C; forming the kneaded material into an abrasive body; Including, the fibers comprise polypropylene fibers; The method for manufacturing an abrasive body, wherein the polypropylene fibers in the abrasive body have intertwining points where the polypropylene fibers are thermally fused together.

15. a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer; Fiber and Abrasives and 1. An abrasive body comprising: the fibers comprise polypropylene fibers; The polypropylene fibers in the polishing body have intertwining points where the polypropylene fibers are thermally fused together.

16. a matrix resin composition containing at least a polyvinyl chloride resin and a plasticizer; Fiber and 1. An abrasive body comprising: The content of the fibers is 10 to 80% by mass, the fibers comprise polypropylene fibers; The polypropylene fibers in the polishing body have intertwining points where the polypropylene fibers are thermally fused together.

17. a matrix resin composition containing at least a polyvinyl chloride resin; Fiber and Abrasives and 1. An abrasive body comprising: the fibers comprise polypropylene fibers; The polypropylene fibers in the polishing body have intertwining points where the polypropylene fibers are thermally fused together.

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