Resin composition molded articles, civil engineering materials, building materials, horticultural materials, and methods for manufacturing resin composition molded articles

Abstract

To provide a resin composition molded article that is less prone to the formation of air bubbles on its surface and exhibits excellent water resistance, a method for manufacturing the same, and civil engineering materials, building materials, and horticultural materials. [Solution] The resin composition molded article is a molded article of a composition comprising a resin substrate containing a low-melting-point resin, cellulose-based material particles dispersed in the resin substrate, and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin has a melting point in the range of 80°C or more and less than 190°C, and the content of the low-melting-point resin relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, the cellulose-based material particles include at least wood powder particles, and the content of the cellulose-based material particles relative to the total amount of the composition is in the range of 10% by mass or more and 50% by mass or less, and the non-low-melting-point resin particles include one or both of a high-melting-point resin and a thermosetting resin with a melting point of 190°C or more, and the content of the non-low-melting-point resin particles relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less.

Description

Technical Field

[0001] The present disclosure relates to a resin composition molded body, civil engineering materials, building materials, gardening materials, and a method for manufacturing a resin composition molded body.

Background Art

[0002] A resin composition molded body in which wood powder particles are dispersed in a resin (matrix material) is known (for example, see Patent Document 1). The resin composition molded body containing wood powder particles is also called wood plastic, and has advantages such as having a texture similar to wood, being less likely to corrode, crack, splinter, and being lightweight compared to wood. Therefore, the resin composition molded body containing wood powder particles is widely used as a material for building materials and the like. The resin composition molded body containing wood powder particles is generally manufactured by heat-molding a raw material composition containing wood powder particles and a thermoplastic resin. As a raw material for the thermoplastic resin, using recycled resin separated and recovered from waste has been considered (for example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Using recycled resin derived from waste as a resin raw material for resin composition molded articles is desirable from the standpoint of promoting resource circulation and significantly contributing to the reduction of CO2 emissions from waste incineration. However, recycled resin derived from waste contains various resins. The inventors have discovered that when recycled resin contains a large amount of high-melting-point resin or thermosetting resin, the water resistance of the resin composition molded article may decrease. Furthermore, they have discovered that when the temperature during heat molding of the resin composition molded article is high, low-molecular-weight components contained in the recycled resin or wood powder may volatilize, causing bubbles to form on the surface of the molded article and impairing its appearance.

[0005] This disclosure aims to provide a resin composition molded article containing cellulosic material particles such as wood powder particles, which exhibits excellent water resistance and is less prone to surface bubble formation even when manufactured using recycled resins including high-melting-point resins and thermosetting resins, as well as a method for manufacturing the same, and civil engineering materials, building materials, and horticultural materials. [Means for solving the problem]

[0006] This disclosure relates to a molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, cellulose-based material particles dispersed in the resin substrate, and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin has a melting point in the range of 80°C or more and less than 190°C, and the content of the low-melting-point resin with respect to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, the cellulose-based material particles include at least wood powder particles, and the content of the cellulose-based material particles with respect to the total amount of the composition is in the range of 10% by mass or more and 50% by mass or less, and the non-low-melting-point resin particles include one or both of a high-melting-point resin and a thermosetting resin with a melting point of 190°C or more, and the content of the non-low-melting-point resin particles with respect to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional view of a resin composition molded article according to one embodiment of the present disclosure. [Figure 2] This is a perspective view of a paving material according to one embodiment of the present disclosure. [Figure 3] This is a cross-sectional view of a road surface paved using a paving material according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described in detail below with reference to the drawings. As shown in Figure 1, the resin composition molded article 10 of this embodiment is a molded article of a composition comprising a resin substrate (matrix material) 11, cellulose-based material particles 12 dispersed in the resin substrate 11, and non-low melting point resin particles 13 dispersed in the resin substrate 11.

[0009] The resin substrate 11 includes a low-melting-point resin. The low-melting-point resin is a thermoplastic resin with a melting point in the range of 80°C or more and less than 190°C. The low-melting-point resin may have a melting point of less than 160°C or 160°C or more. Examples of low-melting-point resins with a melting point in the range of 80°C or more and less than 160°C include polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), polyethylene (PE), polymethyl methacrylate (PMMA), and polycarbonate (PC). Examples of low-melting-point resins with a melting point in the range of 160°C or more and less than 190°C include polypropylene (PP), polyamide 12 (PA12), and polyacetal (POM). The low-melting-point resin may be used alone or in combination of two or more types. For example, if the low-melting-point resin is derived from waste and is a mixture of multiple types of low-melting-point resins, the resins may be sorted and used according to their type, or the mixture may be used as is. When using two or more types in combination, low-melting-point resins with melting points below 160°C may be combined, low-melting-point resins with melting points of 160°C or higher may be combined, or a low-melting-point resin with a melting point below 160°C may be combined with a low-melting-point resin with a melting point of 160°C or higher. The low-melting-point resin may contain at least polyethylene (PE) and polypropylene (PP). The PE and PP content may be expressed as a mass ratio of PE to PP (PE / PP), which may be, for example, 1.4 or less, or 1.2 or less.

[0010] Low-melting-point resins may be derived from waste. For example, low-melting-point resins may be separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law.

[0011] The content of the low-melting-point resin is within the range of 10% by mass or more and 80% by mass or less, as a percentage of the total amount of the resin composition molded article 10. The content of the low-melting-point resin may also be within the range of 10% by mass or more and 50% by mass or less, within the range of 12% by mass or more and 45% by mass or less, or within the range of 15% by mass or more and 45% by mass or less.

[0012] The particle shape of the cellulose-based material particles 12 dispersed in the resin substrate 11 is not particularly limited, and may be spherical, ellipsoidal, cylindrical, prismatic, plate-like, or irregularly shaped. The particle size of the cellulose-based material particles 12 is not particularly limited, but among particles with a major axis of 1.0 mm or more, the content of particles with a major axis of 3.0 mm or more may be 35 percent or less, or 20 percent or less. Also, the content of particles with a major axis of less than 2.0 mm may be 30 percent or more, or 50 percent or less. The content of these particles can be determined by observing the cross-section of the resin composition molded body 10 using an optical microscope and measuring the particle size of the cellulose-based material particles 12.

[0013] The content of cellulose-based material particles 12 with a major axis of 5.0 mm or more is calculated as an average content of 1.0 particles / 100 mm in a 10 mm x 10 mm cross-section of the resin composition molded body 10. 2 The following is also acceptable: 0.5 pieces / 100mm 2 The following may also be true. The average content of cellulose-based material particles 12 can be determined, for example, by dividing the cross-section of the resin composition molded body 10 into 10 mm × 10 mm regions and measuring the particle size of the cellulose-based material particles present in the 1000 regions using an optical microscope.

[0014] The cellulose-based material particles 12 may have passed through a sieve with a mesh size of 3 mm. The cellulose-based material particles 12 may also have passed through a sieve with a mesh size of less than 3 mm. Examples of sieves with a mesh size of less than 3 mm include a sieve with a mesh size of 1 mm and a sieve with a mesh size of 2 mm.

[0015] The cellulose-based material particles 12 contain at least wood powder particles. The cellulose-based material particles 12 may also contain pulp particles as particles other than wood powder particles. The content of wood powder particles relative to the cellulose-based material particles 12 may be 50% by mass or more, or 80% by mass or more. Furthermore, the cellulose-based material particles 12 may contain wood powder particles alone. The cellulose-based material particles 12 may be derived from waste. The wood powder particles may be, for example, crushed waste materials such as construction waste wood separated from construction waste, thinned wood, or sawdust. The pulp particles may be, for example, crushed waste materials such as recycled paper or used cardboard.

[0016] The content of cellulose-based material particles 12 is within the range of 10% by mass or more and 50% by mass or less as a percentage of the total amount of the resin composition molded body 10. The content of cellulose-based material particles 12 may also be within the range of 20% by mass or more and 40% by mass or less. The ratio of the content of cellulose-based material particles 12 to the content of low-melting-point resin contained in the resin substrate 11 (content of cellulose-based material particles 12 / content of low-melting-point resin) may be 5.0 or less, 3.0 or less, less than 3.0, or 2.5 or less. The content of cellulose-based material particles 12 may be varied depending on the size of the cellulose-based material particles 12. For example, in the case of cellulose-based material particles that have passed through a sieve with a mesh opening of 1 mm, the content may be within the range of 10% by mass or more and 50% by mass or less, and the content of cellulose-based material particles / content of low-melting-point resin may be within the range of 0.1 or more and 5.0 or within the range of 0.1 or more and 4.0 or less. For cellulose-based material particles that have passed through a sieve with a mesh size of 2 mm, the content may be in the range of 10% by mass or more and 40% by mass or less, and the ratio of cellulose-based material particle content to low-melting-point resin content may be in the range of 0.1 or more and 3.0 or less, or in the range of 0.1 or more and 2.0 or less. For cellulose-based material particles that have passed through a sieve with a mesh size of 3 mm, the content may be in the range of 10% by mass or more and 40% by mass or less, and the ratio of cellulose-based material particle content to low-melting-point resin content may be in the range of 0.1 or more and 2.0 or less, or in the range of 0.1 or more and 1.0 or less.

[0017] The non-low melting point resin particles 13 dispersed in the resin substrate 11 contain one or both of a high melting point resin and a thermosetting resin. The high melting point resin is a thermoplastic resin having a melting point of 190°C or higher. The melting point of the high melting point resin may be 340°C or lower. Examples of the high melting point resin include polyethylene terephthalate (PET), polyamide 6 (PA6), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK). The thermosetting resin is the resin after curing. Examples of the thermosetting resin include polyimide (PI), polyurethane (PU), and phenol resin (PF).

[0018] The particle shape of the non-low melting point resin particles 13 is not particularly limited, and may be, for example, spherical, ellipsoidal, cylindrical, prismatic, plate-like, or amorphous. The particle size of the non-low melting point resin particles 13 is not particularly limited, but in the case of particles having a major axis of 1.0 mm or more, the content of particles having a major axis of 3.0 mm or more may be 35% by number or less, or may be 20% by number or less. The content of particles having a major axis of less than 2 mm may be 30% by number or more, or may be 50% by number or less. The content of the non-low melting point resin particles 13 having a major axis of 5.0 mm or more is 1.0 particle / 100 mm as the average content contained in the region of the cross section 10 mm × 10 mm of the resin composition molded body 10 2 or less, and may also be 0.5 particle / 100 mm 2 or less.

[0019] The non-low melting point resin particles 13 may pass through a sieve with a mesh size of 3 mm. The non-low melting point resin particles 13 may pass through a sieve having a mesh size of less than 3 mm. As the sieve having a mesh size of less than 3 mm, for example, a sieve with a mesh size of 1 mm or a sieve with a mesh size of 2 mm can be used.

[0020] The non-low melting point resin particles 13 may be derived from waste. The non-low melting point resin particles 13 may be, for example, a pulverized product of a high melting point resin or a thermosetting resin separated and recovered from waste plastics collected in accordance with the container packaging recycling method.

[0021] The content rate of the non-low melting point resin particles 13 is in the range of 10% by mass or more and 80% by mass or less as the content rate with respect to the total amount of the resin composition molded body 10. The content rate of the non-low melting point resin particles 13 may be in the range of 15% by mass or more and 75% by mass or less, or may be in the range of 30% by mass or more and 60% by mass or less. When the resin composition molded body 10 does not contain the non-low melting point resin particles 13, a recycled resin derived from waste containing a non-low melting point resin cannot be used as the resin raw material of the resin composition molded body 10. Therefore, it cannot contribute to the reduction of CO2 emissions by incineration of waste containing a non-low melting point resin.

[0022] The content of the non-low melting point resin particles 13 may be equal to or more than the content of the low melting point resin contained in the resin base material 11. The contents of the non-low melting point resin particles 13 and the low melting point resin are the ratio of the content rate of the non-low melting point resin particles 13 to the content rate of the low melting point resin (content rate of non-low melting point resin particles 13 / content rate of low melting point resin), and may be, for example, 0.2 or more and less than 13, may be more than 0.6 and 10 or less, or may be 1 or more and 8 or less.

[0023] The total amount of the cellulose-based material particles 12 and the non-low melting point resin particles 13 dispersed in the resin base material 11 may be less than or more than the resin base material 11. For example, when the content rate of the low melting point resin contained in the resin base material 11 is X (unit: mass%), the content rate of the non-low melting point resin particles 13 is Y (unit: mass%), and the content rate of the cellulose-based material particles 12 is Z (unit: mass%), the difference (Y + Z) - X between the particle content (Y + Z) and the low melting point resin may satisfy, for example, the following formula (1). (Y + Z) - X ≧ -10 (1)

[0024] Also, (Y + Z) - X may satisfy the following formula (2). 79 ≧ (Y + Z) - X ≧ 1 (2)

[0025] <000,0109>The resin composition molded article 10 of this embodiment may further contain additives. As additives, various additives that are conventionally applied to wood plastics can be used, such as compatibilizers, pigments, weather resistance improvers, lubricants, heat stabilizers, fillers, foaming agents, and antistatic agents. The content of the additive is, for example, within the range of 3% by mass or more and 10% by mass or less as a percentage of the total amount of the resin composition molded article 10. The additive may be melted in the resin substrate 11 or dispersed in the resin substrate 11.

[0026] The resin composition molded article 10 of this embodiment may contain unavoidable impurities. Unavoidable impurities are impurities that are inevitably mixed in during the raw material or production process. Examples of unavoidable impurities include aluminum derived from aluminum-deposited plastic contained in waste plastic used as a raw material for low-melting-point resins or non-low-melting-point resin particles 13. The aluminum content relative to the total amount of the resin composition molded article 10 may be, for example, less than 1% by mass, less than 0.5% by mass, or less than 0.2% by mass.

[0027] In the resin composition molded article 10 of this embodiment, which has the above configuration, the content of low-melting-point resin contained in the resin substrate 11 is within the above range. For this reason, it can be manufactured at a heating temperature of less than 190°C, for example, and this suppresses the volatilization of low molecular weight components contained in low-melting-point resins, non-low-melting-point resins, and cellulose-based materials, while dispersing cellulose-based material particles 12 and non-low-melting-point resin particles 13 in the resin substrate 11, so that the cellulose-based material particles 12 and non-low-melting-point resin particles 13 do not easily absorb water. Therefore, even if the resin composition molded article 10 of this embodiment is manufactured using recycled resin derived from waste containing non-low-melting-point resins such as high-melting-point resins and thermosetting resins, bubbles are less likely to form on the surface and it exhibits excellent water resistance. By using recycled resin containing non-low-melting-point resins, it is possible to contribute to the reduction of CO2 emissions from the incineration of waste. In the resin composition molded article 10 of this embodiment, the equilibrium expansion rate measured by the measurement method described below may be 20% or less, particularly 10% or less, as an indicator of water resistance.

[0028] (Measurement method) The resin composition molded body 10 is immersed in hot water adjusted to 60°C until the rate of change in the thickness of the resin composition molded body 10 per day becomes 0.5% or less. The thickness of the resin composition molded body 10 when the rate of change in thickness becomes 0.5% or less is defined as Tf (unit: mm), and the thickness of the resin composition molded body 10 before immersion in the hot water is defined as Ti (unit: mm). The equilibrium expansion rate is calculated using the following formula (3). Equilibrium expansion coefficient (%) = {(Tf-Ti) / Ti} × 100 (3)

[0029] Furthermore, in the resin composition molded body 10 of this embodiment, the cellulose-based material particles 12 have a particle size within the above range, and their content in the resin composition molded body 10 is within the above range, thus improving the texture of the resin composition molded body 10 due to the cellulose-based material particles 12. For example, if the cellulose-based material particles 12 are wood powder particles, the resin composition molded body 10 will have an excellent wood-like texture. Moreover, since the non-low melting point resin particles 13 have a content within the above range in the resin composition molded body 10, high melting point resins and thermosetting resins, which are often disposed of by incineration, can be effectively utilized, greatly contributing to the reduction of CO2 emissions from waste incineration.

[0030] In the resin composition molded article 10 of this embodiment, if the cellulose material particles 12 have a major diameter of 1.0 mm or more, and the content of particles with a major diameter of 3.0 mm or more is 35 percent or less, the particle size of the cellulose material particles 12 is small, making it easier to coat the surface of the cellulose material particles 12 with a low-melting-point resin. As a result, the cellulose material particles 12 are less likely to fall off the resin composition molded article 10 and are less likely to absorb water, improving the water resistance of the resin composition molded article 10. Furthermore, if the cellulose material particles 12 have passed through a sieve with a mesh size of 3 mm, it becomes less likely for coarse cellulose material particles 12 to be mixed in, so the surface of the cellulose material particles 12 can be more reliably coated with a low-melting-point resin.

[0031] In the resin composition molded body 10 of this embodiment, if the non-low melting point resin particles 13 are particles with a major axis of 1.0 mm or more, and the content of particles with a major axis of 3.0 mm or more is 35 percent or less, the particle size of the non-low melting point resin particles 13 is small, making it easier to coat the surface of the non-low melting point resin particles 13 with low melting point resin. As a result, the non-low melting point resin particles 13 are less likely to fall off the resin composition molded body 10. Furthermore, if the non-low melting point resin particles 13 have passed through a sieve with a mesh size of 3 mm, it becomes less likely for coarse non-low melting point resin particles 13 to be mixed in, so the surface of the non-low melting point resin particles 13 can be more reliably coated with low melting point resin.

[0032] In the resin composition molded article 10 of this embodiment, if the ratio of the content of cellulose-based material particles 12 to the content of low-melting-point resin contained in the resin substrate 11 is 3.0 or less, the surface of the cellulose-based material particles 12 can be more reliably coated with the low-melting-point resin.

[0033] In the resin composition molded article 10 of this embodiment, if the low-melting-point resin contained in the resin substrate 11 includes polyethylene with a melting point of less than 160°C and polypropylene with a melting point of 160°C or higher, the fluidity of the resin substrate 11 is improved by heating, allowing the cellulose-based material particles 12 and non-low-melting-point resin particles 13 to be dispersed more uniformly, and reducing the likelihood of air bubbles. When the mass ratio of polyethylene to polypropylene is 1.4 or less, the effects of using polyethylene and polypropylene together can be obtained more reliably.

[0034] The resin composition molded body 10 of this embodiment can be used, for example, as civil engineering materials, building materials, and gardening materials. Examples of civil engineering materials include paving materials. Examples of building materials include flooring materials, especially bathroom flooring materials, roofing materials, wall materials, handrails, sashes, wood decks, and fences. Examples of gardening materials include flower beds. Since the resin composition molded body 10 has excellent water resistance, it is particularly useful as paving materials and building materials used outdoors. Furthermore, a resin composition molded body 10 containing wood powder particles, in which the cellulose material particles 12 are wood powder particles, can be used as wood plastic. There are no particular restrictions on the shape of the resin composition molded body 10, and it can be in the shape of a block, plate, or column according to the purpose of use.

[0035] Next, an embodiment of a paving material using the resin composition molded body 10 of this embodiment will be described. As shown in Figure 2, the paving material 20 of this embodiment is a square plate-like body in plan view. The surface 21 of the paving material 20 has a plurality of protrusions extending parallel to each other. One of a pair of opposing sides of the paving material 20 has a male tongue 22 and the other has a female tongue 23.

[0036] As shown in Figure 3, the paving material 20 is laid on top of a laminate formed in the order of floor concrete 33 and leveling material 34 within the area enclosed by curb blocks 32 of the subgrade 31. The floor concrete 33 has reinforcing bars inside. Mortar or sprinkled sand can be used as the leveling material 34.

[0037] The paving material 20 is joined by fitting together male and female grooves 22 and 23. During rainfall, rainwater flows out to the outside through the space between the male and female grooves 22 and 23 of the paving material 20. Therefore, rainwater does not easily accumulate on the surface 21 of the paving material 20.

[0038] Next, the manufacturing method for the resin composition molded article 10 of this embodiment will be described. The resin composition molded body 10 can be manufactured, for example, by a method that includes a preparation step of preparing raw material composition powder and a forming step of forming the resin composition molded body 10 using the raw material composition powder.

[0039] The raw material composition powder prepared in the preparation step is a powder of a composition containing low-melting-point resin particles derived from waste, cellulose-based material particles, and non-low-melting-point resin particles derived from waste. The low-melting-point resin particles include low-melting-point resins with a melting point in the range of 80°C to less than 190°C. The low-melting-point resin particles may have passed through a sieve with a mesh size of 3 mm. The content of the low-melting-point resin is in the range of 10% to 80% by mass as a percentage of the total amount of the raw material composition powder. The cellulose-based material particles may have passed through a sieve with a mesh size of 3 mm. The content of the cellulose-based material particles is in the range of 20% to 50% by mass as a percentage of the total amount of the raw material composition powder. The non-low-melting-point resin particles include either or both high-melting-point resins and thermosetting resins with a melting point of 190°C or higher. The non-low-melting-point resin particles may have passed through a sieve with a mesh size of 3 mm. The content of non-low melting point resin particles is within the range of 10% by mass or more and 80% by mass or less, as a percentage of the total amount of raw material composition powder.

[0040] The raw material composition powder can be produced, for example, by mixing low-melting-point resin particles, cellulose-based material particles, and non-low-melting-point resin particles in proportions such that their content is within the above range. Alternatively, the raw material composition powder can also be produced by mixing, for example, lumps of low-melting-point resin, lumps of cellulose-based material, and lumps of non-low-melting-point resin particles in proportions such that their content is within the above range, pulverizing the resulting mixture, and then classifying it using a sieve with a mesh size of 3 mm or less.

[0041] The particle size of the cellulose-based material particles and non-low melting point resin particles in the raw material composition powder may be within the range of 10% to 85% of particles smaller than 1.0 mm, 15% to 50% of particles between 1.0 mm and 2.0 mm, 0% to 40% of particles between 2.0 mm and 3.0 mm, and 0% to 30% of particles or larger.

[0042] In the forming process, the raw material composition powder is heated and kneaded at a temperature above the melting point of the low-melting-point resin particles, but below 190°C. The kneading temperature may be 150°C or higher, or within the range of 165°C to 180°C. Heating and kneading generates a molten material in which the low-melting-point resin particles in the raw material composition powder are melted. The generated molten material is then molded into the desired shape. Various methods used for molding thermoplastic resins, such as extrusion molding and injection molding, can be used as the molding method for the molten material.

[0043] According to the method for manufacturing the resin composition molded article 10 of this embodiment, which has the above configuration, the kneading temperature in the forming process is within the above range, so the low molecular weight components contained in the raw material composition powder are less likely to volatilize. For this reason, the resulting resin composition molded article 10 is less prone to generating air bubbles. In the method for manufacturing the resin composition molded article 10 of this embodiment, if the particle size of the cellulose-based material particles and the non-low melting point resin particles is within the above range, a resin composition molded article 10 with a uniform composition and high water resistance can be obtained without pelletizing the raw material composition powder before the forming process. However, even in the method for manufacturing the resin composition molded article 10 of this embodiment, the raw material composition powder may be pelletized before the forming process. [Examples]

[0044] The present disclosure will be described in more detail below based on examples. The present disclosure is not limited by these examples. In these examples, the following low-melting-point resin, wood chips, and non-low-melting-point resin were used as raw materials. Low-melting-point resin powder (PE powder): This is made by crushing polyethylene that has been separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law (melting point: 150°C). Low-melting-point resin powder (PP powder): This is made by crushing polypropylene that has been separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law (melting point: 160°C). Non-low melting point resin powder (PET powder): Polyethylene terephthalate separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law is crushed and classified using sieves with mesh sizes of 1 mm, 2 mm, and 3 mm (melting point: 250°C). Wood powder: This is produced by crushing construction waste wood separated from construction waste materials and classifying it using sieves with mesh sizes of 1 mm, 2 mm, and 3 mm.

[0045] Table 1 below shows the particle size distribution of PET powder and wood powder classified using sieves with mesh sizes of 1 mm, 2 mm, and 3 mm. In Table 1, the 1 mm classified, 2 mm classified, and 3 mm classified samples were classified using sieves with mesh sizes of 1 mm, 2 mm, and 3 mm, respectively. The particle size distribution of PET powder and wood powder was obtained by measuring the longest diameter of 1000 particles using a microscope and an image dimension measuring instrument, and calculating the percentage of particles smaller than 1.0 mm, the percentage of particles between 1.0 mm and 2.0 mm, the percentage of particles between 2.0 mm and 3.0 mm, and the percentage of particles larger than 3.0 mm. The particle size distribution of PET powder and wood powder was measured three times each.

[0046] [Table 1]

[0047] [Example 1] A raw material composition powder was prepared by mixing 10 parts by mass of PE powder, 5 parts by mass of PP powder, 50 parts by mass of PET powder (2 mm graded), and 30 parts by mass of wood powder (2 mm graded). 90 parts by mass of this raw material composition powder was mixed with 10 parts by mass of additives, and the resulting mixture was fed into an extrusion molding machine to produce the paving material shown in Figure 2 under conditions of a mixing and molding temperature of 165°C. The additives used were a compatibilizer, pigment, weather resistance improver, lubricant, and heat stabilizer. The resulting paving material was a plate-like body measuring 300 mm in length, 300 mm in width, and 30 mm in thickness. The content ratios of low-melting-point resins (PE, PP), non-low-melting-point resins (PET), wood powder, and additives in the resulting paving material were the same as the mixing ratios of the raw materials.

[0048] [Examples 2-15, Comparative Examples 1-5] A raw material composition powder was prepared in the same manner as in Example 1, except that the mixing ratios of PE powder, PP powder, PET powder, and wood powder were changed to the ratios shown in Table 2 below, and the types of PET powder and wood powder were changed to those shown in Table 2 below. Then, using the obtained raw material composition powder, a paving material was prepared in the same manner as in Example 1, except that the mixing and molding temperature of the extrusion molding machine was set to the temperature shown in Table 2 below. In Comparative Example 3, a non-low melting point resin was not used.

[0049] [evaluation] The obtained paving materials were evaluated for the ratio of non-low melting point resins, appearance (wood-like texture, foamed appearance), and water resistance (equilibrium expansion rate) as described below. The results are shown in Table 2 below.

[0050] <Ratio of non-low melting point resins> The proportion of non-low melting point resin in the paving material was calculated. Cases where the proportion of non-low melting point resin exceeded 10% by mass were designated as "A," and cases where it was 10% by mass or less were designated as "B."

[0051] <Exterior (wood texture, foamed)> The surface of the paving material was visually inspected. The wood texture was evaluated visually. A grade was assigned to items with a variation from light to dark brown and a wood texture, a grade was assigned to items that were only dark brown and had a wood texture, and a grade was assigned to items that were only dark brown and did not have a wood texture. Foaming was evaluated by measuring the expansion in the thickness direction immediately after removal from the extrusion molding machine mold. Expansion of less than 0.5 mm was classified as "A", 0.5 mm or more but less than 2.0 mm as "B", and 2.0 mm or more as "C".

[0052] <Water resistance (equilibrium expansion coefficient)> The paving material is immersed in hot water adjusted to 60°C. The paving material is removed from the hot water every day, and its thickness is measured. The rate of change in the thickness of the paving material relative to the thickness of the paving material on the previous day is calculated using the following formula. Percentage change in paving material thickness (%) = (Paving material thickness - Previous day's paving material thickness) / Previous day's paving material thickness × 100

[0053] When the rate of change in the thickness of the paving material becomes 0.5% or less, the rate of expansion of the paving material thickness due to water absorption is assumed to have reached equilibrium, and the equilibrium rate of expansion of the paving material thickness is calculated using the following formula (3). Note that the thickness of the paving material is the average of the thicknesses at five locations: the central part of the plane and the vicinity of each of the four corners. Equilibrium expansion coefficient (%) = {(Tf-Ti) / Ti} × 100 (3) In formula (3), Tf (unit: mm) is the thickness of the resin composition molded article when the rate of change in thickness is 0.5% or less, and Ti (unit: mm) is the thickness of the resin composition molded article before immersion in hot water. Water resistance was categorized as follows: "A" if the equilibrium expansion coefficient was 10% or less, "B" if it was between 10% and 20%, and "C" if it was above 20%.

[0054] [Table 2]

[0055] The results shown in Table 2 indicate that paving materials in which the content of low-melting-point resin, non-low-melting-point resin particles, and wood powder particles falls within the range of this disclosure exhibit excellent appearance and water resistance. Therefore, this paving material can be advantageously used as a paving material for outdoor use. In particular, the paving materials obtained in Examples 1-6, where 2mm graded wood powder was used and the wood powder / low-melting-point resin ratio was 2.0 or less, and in Examples 8, 10-12, and 14, where 1mm graded wood powder was used and the wood powder / low-melting-point resin ratio was 4.0 or less, exhibit excellent water resistance, with a water resistance rating of A (equilibrium expansion rate in 60°C hot water of 10% or less).

[0056] In contrast, the paving materials obtained in Comparative Examples 1 and 2, which had a lower low-melting-point resin content compared to the scope of this disclosure, had a water resistance rating of C (equilibrium expansion rate in 60°C hot water exceeding 20%). This is because, due to the low low-melting-point resin content, some of the wood powder particles were not coated with the low-melting-point resin, making them more susceptible to absorbing hot water. Comparative Example 3, which did not use a non-low-melting-point resin, showed excellent water resistance, but it did not contribute to reducing CO2 emissions from the incineration of waste containing non-low-melting-point resins. Comparative Example 4, which had a higher wood powder content compared to the scope of this disclosure, had a water resistance rating of C. This is because, due to the high wood powder content, it was more susceptible to absorbing hot water.

[0057] [Comparative Example 5] The paving material was prepared in the same manner as in Example 3, except that the mixing and molding temperature of the extrusion molding machine was set to 200°C. The resulting paving material received a foaming evaluation result of C. This is because low-molecular-weight components contained in the raw material composition powder volatilized, causing bubbles to form on the surface of the paving material.

[0058] The nature of this disclosure is described below. (Note 1) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, cellulose-based material particles dispersed in the resin substrate, and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin has a melting point in the range of 80°C or more and less than 190°C, and the content of the low-melting-point resin with respect to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, the cellulose-based material particles include at least wood powder particles, and the content of the cellulose-based material particles with respect to the total amount of the composition is in the range of 10% by mass or more and 50% by mass or less, and the non-low-melting-point resin particles include one or both of a high-melting-point resin and a thermosetting resin with a melting point of 190°C or more, and the content of the non-low-melting-point resin particles with respect to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less.

[0059] (Note 2) The resin composition molded article according to Appendix 1, wherein the cellulose-based material particles and the non-low melting point resin particles have a major axis of 1.0 mm or more, and the content of particles with a major axis of 3.0 mm or more is 35 percent or less.

[0060] (Note 3) A resin composition molded article as described in Appendix 2, wherein the content of particles with a major axis of 3.0 mm or more is 20 percent or less.

[0061] (Note 4) The resin composition molded article according to any one of the appendices 1 to 3, wherein the cellulose-based material particles and the non-low melting point resin particles are passed through a sieve with a mesh size of 3 mm.

[0062] (Note 5) The resin composition molded article described in Appendix 4, wherein the cellulose-based material particles and the non-low melting point resin particles have been passed through a sieve with a mesh size of 2 mm.

[0063] (Note 6) A resin composition molded article according to any one of the appendices 1 to 5, wherein the ratio of the content of cellulose-based material particles to the content of the low-melting-point resin (cellulose-based material particles / low-melting-point resin) is 5.0 or less.

[0064] (Note 7) A resin composition molded article according to Appendix 6, wherein the ratio of the content of cellulose-based material particles to the content of the low-melting-point resin (cellulose-based material particles / low-melting-point resin) is 3.0 or less.

[0065] (Note 8) A resin composition molded article according to Appendix 7, wherein the ratio of the content of cellulose-based material particles to the content of the low-melting-point resin (cellulose-based material particles / low-melting-point resin) is 2.5 or less.

[0066] (Note 9) A resin composition molded article according to any one of appendices 1 to 8, wherein the low-melting-point resin comprises at least two types of resins.

[0067] (Note 10) A resin composition molded article according to Appendix 9, wherein the low-melting-point resin comprises at least polyethylene and polypropylene.

[0068] (Note 11) A resin composition molded article according to Appendix 10, wherein the content of polyethylene and polypropylene is 1.4 or less in mass ratio of polyethylene to polypropylene.

[0069] (Note 12) A resin composition molded article according to Appendix 11, wherein the content of polyethylene and polypropylene is 1.2 or less in mass ratio of polyethylene to polypropylene.

[0070] (Note 13) A resin composition molded article according to any one of the appendices 1 to 12, wherein the content of the low-melting-point resin is in the range of 10% by mass or more and 50% by mass or less.

[0071] (Note 14) A resin composition molded article according to any one of the appendices 1 to 13, wherein the content of the non-low melting point resin particles is equal to or greater than the content of the low melting point resin.

[0072] (Note 15) A resin composition molded article according to any one of the appendices 1 to 14, wherein the content of the non-low melting point resin particles is in the range of 15% by mass or more and 75% by mass or less.

[0073] (Note 16) A resin composition molded article according to Appendix 15, wherein the content of the non-low melting point resin particles is in the range of 30% by mass or more and 60% by mass or less.

[0074] (Note 17) A resin composition molded article according to any one of the appendices 1 to 16, wherein the aluminum content relative to the total amount of the composition is less than 1% by mass.

[0075] (Note 18) A resin composition molded article according to any one of the appendices 1 to 17, wherein when the content of the low-melting-point resin is X (unit: mass%), the content of the non-low-melting-point resin particles is Y (unit: mass%), and the content of the cellulose-based material particles is Z (unit: mass%), (Y+Z)-X satisfies the following formula (1). (Y+Z)-X≧-10 (1)

[0076] (Note 19) A resin composition molded article as described in Appendix 18, wherein (Y+Z)-X satisfies the following formula (2). 79≧(Y+Z)-X≧1 (2)

[0077] (Note 20) A molded resin composition according to any one of the appendices 1 to 19, wherein the equilibrium expansion coefficient measured by the measurement method described below is 20% or less. (Measurement method) The resin composition molded body is immersed in hot water adjusted to 60°C until the rate of change in the thickness of the resin composition molded body per day becomes 0.5% or less. The thickness of the resin composition molded body when the rate of change in thickness becomes 0.5% or less is defined as Tf (unit: mm), and the thickness of the resin composition molded body before immersion in the hot water is defined as Ti (unit: mm). The equilibrium expansion rate is calculated using the following formula (3). Equilibrium expansion coefficient (%) = {(Tf-Ti) / Ti} × 100 (3)

[0078] (Note 21) A resin composition molded article according to Appendix 20, wherein the equilibrium expansion rate is 10% or less.

[0079] (Note 22) A molded resin composition according to any one of the appendices 1 to 21, which is in the shape of a block, plate, or column.

[0080] (Note 23) Civil engineering materials comprising a molded resin composition described in any one of the appendices 1 to 22.

[0081] (Note 24) A building material comprising a molded resin composition described in any one of the appendices 1 to 22.

[0082] (Note 25) Horticultural materials comprising a molded resin composition described in any one of the appendices 1 to 22.

[0083] (Note 26) A method for producing a resin composition molded article, comprising: preparing a raw material composition powder comprising waste-derived low-melting-point resin particles, cellulose-based material particles, and waste-derived non-low-melting-point resin particles, wherein the low-melting-point resin particles include a low-melting-point resin having a melting point in the range of 80°C or more and less than 190°C, the content of the low-melting-point resin relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, the content of the cellulose-based material particles relative to the total amount of the composition is in the range of 10% by mass or more and 50% by mass or less, and the non-low-melting-point resin particles include one or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more, and the content of the non-low-melting-point resin particles relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, and heating and kneading the raw material composition powder at a temperature above the melting point of the low-melting-point resin particles and below 190°C.

[0084] (Note 27) The method for producing a resin composition molded article as described in Appendix 26, wherein the cellulose-based material particles and the non-low melting point resin particles are passed through a sieve with a mesh size of 3 mm. [Explanation of symbols]

[0085] 10…Resin composition molded body, 11…Resin substrate, 12…Cellulose-based material particles, 13…Non-low melting point resin particles, 20…Paving material, 21…Surface, 22…Male tongue and groove, 23…Female tongue and groove, 31…Subgrade, 32…Curb block, 33…Floor concrete, 34…Leveling material

Claims

1. A molded article of a composition comprising a resin substrate containing a low-melting-point resin, cellulosic material particles dispersed in the resin substrate, and non-low-melting-point resin particles dispersed in the resin substrate, The low-melting-point resin has a melting point in the range of 80°C or more and less than 190°C, and its content relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less. The cellulose-based material particles include at least wood powder particles. The content of the cellulose-based material particles relative to the total amount of the composition is within the range of 10% by mass or more and 50% by mass or less. The non-low melting point resin particles include one or both of a high melting point resin and a thermosetting resin having a melting point of 190°C or higher, and the content of the non-low melting point resin particles relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less, in a resin composition molded article.

2. The resin composition molded article according to claim 1, wherein the cellulose-based material particles and the non-low melting point resin particles have a major diameter of 1.0 mm or more, and the content of particles with a major diameter of 3.0 mm or more is 35 percent or less.

3. The resin composition molded article according to claim 1 or 2, wherein the cellulose-based material particles and the non-low melting point resin particles are passed through a sieve with a mesh size of 3 mm.

4. A resin composition molded article according to any one of claims 1 to 3, wherein the ratio of the content of cellulose-based material particles to the content of the low-melting-point resin is 5.0 or less.

5. A resin composition molded article according to any one of claims 1 to 4, wherein the low-melting-point resin comprises at least two types of resins.

6. The resin composition molded article according to claim 5, wherein the low-melting-point resin comprises at least polyethylene and polypropylene.

7. The resin composition molded article according to claim 6, wherein the content of polyethylene and polypropylene is 1.4 or less in mass ratio of polyethylene to polypropylene.

8. A resin composition molded article according to any one of claims 1 to 7, wherein the content of the low-melting-point resin is in the range of 10% by mass or more and 50% by mass or less.

9. A resin composition molded article according to any one of claims 1 to 8, wherein the content of the non-low melting point resin particles is equal to or greater than the content of the low melting point resin.

10. A molded resin composition according to any one of claims 1 to 9, which is in the shape of a block, a plate, or a column.

11. A civil engineering material comprising a molded resin composition according to any one of claims 1 to 10.

12. A building material comprising a molded resin composition according to any one of claims 1 to 10.

13. A horticultural material comprising a molded resin composition according to any one of claims 1 to 10.

14. A powder composition comprising waste-derived low-melting-point resin particles, cellulosic material particles, and waste-derived non-low-melting-point resin particles, The low-melting-point resin particles include a low-melting-point resin having a melting point in the range of 80°C or more and less than 190°C, and the content of the low-melting-point resin relative to the total amount of the composition is in the range of 10% by mass or more and 80% by mass or less. The content of the cellulose-based material particles relative to the total amount of the composition is within the range of 10% by mass or more and 50% by mass or less. The non-low melting point resin particles are prepared by providing a raw material composition powder that contains either or both a high melting point resin and a thermosetting resin, with a melting point of 190°C or higher, and the content of the non-low melting point resin particles relative to the total amount of the composition is within the range of 10% by mass or more and 80% by mass or less. A method for producing a resin composition molded article, comprising heating and kneading the raw material composition powder at a temperature above the melting point of the low-melting-point resin particles and below 190°C.

15. The method for producing a molded resin composition according to claim 14, wherein the cellulose-based material particles and the non-low melting point resin particles are passed through a sieve with a mesh size of 3 mm.

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