Resin composition molded body, civil engineering material, building material, horticultural material, and method for producing resin composition molded body

Abstract

A resin composition molded body (10) according to the present disclosure is a molded body of a composition containing a resin base material (11) that contains a low-melting-point resin, cellulose-based material particles (12) that are dispersed in the resin base material 11, and non-low-melting-point resin particles (13) that are dispersed in the resin base material (11), wherein the low-melting-point resin has a melting point within the range of at least 80°C to less than 190°C, the low-melting-point resin content relative to the total amount of the composition is within the range of 10-80 mass%, the cellulose-based material particles (12) content relative to the total amount of the composition is within the range of 10-50 mass%, the non-low-melting-point resin particles (13) 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 non-low-melting-point resin particles (13) content with respect to the total amount of the composition is within the range of 10-80 mass%.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a resin composition molded body, a civil engineering material, a building material, a horticultural material, and a method for producing a resin composition molded body.BACKGROUND ART

[0002] A resin composition molded body in which wood powder particles are dispersed in a resin (a matrix material) is known (see Patent Document 1, for example). The resin composition molded body containing the wood powder particles is also called wood plastic, and has advantages of corrosion resistance, crack resistance, split resistance, and light weight in comparison with wood while having wood-like texture. For these reasons, the resin composition molded body containing the wood powder particles is widely used as materials such as a building material. The resin composition molded body containing the wood powder particles is commonly produced by heating and molding a raw material composition containing the wood powder particles and a thermoplastic resin. It has been studied to use, as a raw material for the thermoplastic resin, a recycled resin separated and recovered from waste (see Patent Document 2, for example).Citation ListPatent Documents

[0003] Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2015-529582 Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2001-353707 DISCLOSURE OF THE INVENTIONProblems to be Solved by the Invention

[0004] Using the recycled resin derived from waste as the resin raw material for the resin composition molded body is desirable from the viewpoint of accelerating resource circulation to significantly contribute to reduction in CO 2 emissions due to incineration of the waste. However, the recycled resin derived from waste contains various resins. The present inventors have discovered a problem in that water resistance of the resin composition molded body may deteriorate when the recycled resin contains a large amount of a high-melting-point resin and a thermosetting resin. The present inventors also have discovered a problem in that high temperature for heating and molding the resin composition molded body causes volatilization of low-molecular-weight components contained in the recycled resin and the wood powder to produce foam on a surface of the molded body, which may deteriorate the appearance.

[0005] An object of the present disclosure is to provide: a resin composition molded body that contains cellulose-based material particles such as the wood powder particles, that is less likely to produce foam on the surface even when produced by using the recycled resin containing the high-melting-point resin and the thermosetting resin, and that exhibits excellent water resistance; a producing method therefor; and a civil engineering material, a building material, and a horticultural material.Means for Solving the Problems

[0006] The present disclosure relates to a resin composition molded body that is a molded body of a composition including: a resin base material containing a low-melting-point resin; cellulose-based material particles dispersed in the resin base material; and non-low-melting-point resin particles dispersed in the resin base material. The low-melting-point resin has a melting point of 80°C or higher and lower than 190°C, and a content ratio of the low-melting-point resin relative to an entire amount of the composition is 10 mass% or more and 80 mass% or less, the cellulose-based material particles contain at least wood powder particles, a content ratio of the cellulose-based material particles relative to the entire amount of the composition is 10 mass% or more and 50 mass% or less, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin, and a content ratio of the non-low-melting-point resin particles relative to the entire amount of the composition is 10 mass% or more and 80 mass% or less.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a sectional view of a resin composition molded body according to one embodiment of the present disclosure; FIG. 2 is a perspective view of a paving material according to one embodiment of the present disclosure; and FIG. 3 is a sectional view of a road surface paved by using a paving material according to one embodiment of the present disclosure. PREFERRED MODE FOR CARRYING OUT THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. As illustrated in FIG. 1, a resin composition molded body 10 of the present embodiment is a molded body of a composition containing: a resin base material (a matrix material) 11; cellulose-based material particles 12 dispersed in the resin base material 11; and non-low-melting-point resin particles 13 dispersed in the resin base material 11.

[0009] The resin base material 11 contains a low-melting-point resin. The low-melting-point resin is a thermoplastic resin having a melting point within the range of 80°C or higher and lower than 190°C. The melting point of the low-melting-point resin may be lower than 160°C, or may be 160°C or higher. Examples of the low-melting-point resin having a melting point within the range of 80°C or higher and lower than 160°C include polystyrene (PS), acrylonitrile-butadiene-styrene resin (ABS), polyethylene (PE), polymethyl methacrylate (PMMA), and polycarbonate (PC). Examples of the low-melting-point resin having a melting point within the range of 160°C or higher and lower than 190°C include polypropylene (PP), polyamide 12 (PA12), and polyacetal (POM). The low-melting-point resin may be used singly, or may be used in combination of two or more thereof. For example, when the low-melting-point resin is derived from waste, and is a mixture in which a plurality of types of the low-melting-point resin are mixed, the mixture may be separated for use according to the type of the resin, or may be used as it is. When two or more of the resins are combined for use, the low-melting-point resins having a melting point of lower than 160°C may be combined, the low-melting-point resins having a melting point of 160°C or higher may be combined, or the low-melting-point resin having a melting point of lower than 160°C and the low-melting-point resin having a melting point of 160°C or higher may be combined. The low-melting-point resin may contain at least polyethylene (PE) and polypropylene (PP). A mass ratio (PE / PP) of a content of PE relative to a content of PP may be 1.4 or less or 1.2 or less, for example.

[0010] The low-melting-point resin may be derived from waste. The low-melting-point resin may be resin separated and recovered from waste plastic collected in accordance with The Containers and Packaging Recycling Act, for example.

[0011] A content ratio of the low-melting-point resin is within the range of 10 mass% or more and 80 mass% or less as a content ratio relative to the entire amount of the resin composition molded body 10. The content ratio of the low-melting-point resin may be within the range of 10 mass% or more and 50 mass% or less, may be within the range of 12 mass% or more and 45 mass% or less, and may be within the range of 15 mass% or more and 45 mass% or less.

[0012] A particle shape of the cellulose-based material particles 12 dispersed in the resin base material 11 is not particularly limited, and may be a spherical shape, an ellipsoidal shape, a cylindrical shape, a prismatic shape, a plate shape, or an irregular shape, for example. A particle size of the cellulose-based material particles 12 is not particularly limited, and among particles having a major axis of 1.0 mm or more, a content ratio of particles having a major axis of 3.0 mm or more may be 35 number % or less, and may be 20 number % or less. A content ratio of particles having a major axis of less than 2.0 mm may be 30 number % or more, and may be 50 number % or less. The content ratio of these particles can be determined by observing a cross section of the resin composition molded body 10 by using an optical microscope to measure particle diameters of the cellulose-based material particles 12.

[0013] A content of the cellulose-based material particles 12 having a major axis of 5.0 mm or more may be 1.0 or less per100 mm 2< , and may be 0.5 or less per 100 mm 2< as an average content contained in a region of a cross section with 10 mm × 10 mm of the resin composition molded body 10. The average content of the cellulose-based material particles 12 can be determined by, for example, dividing the cross section of the resin composition molded body 10 into regions of 10 mm × 10 mm, and measuring particle diameters of cellulose-based material particles present in the divided 1000 regions by using an optical microscope.

[0014] The cellulose-based material particles 12 may be particles passed through a sieve having an aperture size of 3 mm. The cellulose-based material particles 12 may be particles that can pass through a sieve having an aperture size of less than 3 mm. As the sieve having an aperture size of less than 3 mm, a sieve having an aperture size of 1 mm or a sieve having an aperture size of 2 mm may be used, for example.

[0015] The cellulose-based material particles 12 contain at least wood powder particles. The cellulose-based material particles 12 may contain pulp particles as particles other than the wood powder particles. A content ratio of the wood powder particles relative to the cellulose-based material particles 12 may be 50 mass% or more, and may be 80 mass% or more. The cellulose-based material particles 12 may singly contain the wood powder particles. The cellulose-based material particles 12 may be derived from waste. The wood powder particles may be, for example, a crushed product of a waste material such as a building waste wood separated from a building waste material, thinned timber, and sawdust. The pulp particles may be, for example, a crushed product of a waste material such as used paper and used cardboard.

[0016] A content ratio of the cellulose-based material particles 12 is within the range of 10 mass% or more and 50 mass% or less as a content ratio relative to the entire amount of the resin composition molded body 10. The content ratio of the cellulose-based material particles 12 may be within the range of 20 mass% or more and 40 mass% or less. A ratio of the content ratio of the cellulose-based material particles 12 relative to the content ratio of the low-melting-point resin contained in the resin base material 11 (the content ratio of the cellulose-based material particles 12 / the content ratio of the low-melting-point resin) may be 5.0 or less, may be 3.0 or less, may be less than 3.0, and may be 2.5 or less. The content ratio of the cellulose-based material particles 12 may be changed according to a size of the cellulose-based material particles 12. For example, in a case of the cellulose-based material particles passed through a sieve having an aperture size of 1 mm, the content ratio may be within the range of 10 mass% or more and 50 mass% or less, and the content ratio of the cellulose-based material particles / the content ratio of the low-melting-point resin may be within the range of 0.1 or more and 5.0 or less and may be within the range of 0.1 or more and 4.0 or less. In a case of the cellulose-based material particles passed through a sieve having an aperture size of 2 mm, the content ratio may be within the range of 10 mass% or more and 40 mass% or less, and the content ratio of the cellulose-based material particles / the content ratio of the low-melting-point resin may be within the range of 0.1 or more and 3.0 or less and may be within the range of 0.1 or more and 2.0 or less. In a case of the cellulose-based material particles passed through a sieve having an aperture size of 3 mm, the content ratio may be within the range of 10 mass% or more and 40 mass% or less, and the content ratio of the cellulose-based material particles / the content ratio of the low-melting-point resin may be within the range of 0.1 or more and 2.0 or less and may be within 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 base material 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 a cured resin. Examples of the thermosetting resin include polyimide (PI), polyurethane (PU), and phenol resin (PF).

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

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

[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 high-melting-point resin separated and recovered from waste plastic collected in accordance with The Containers and Packaging Recycling Act or may be a crushed product of a thermosetting resin.

[0021] A content ratio of the non-low-melting-point resin particles 13 is within the range of 10 mass% or more and 80 mass% or less as a content ratio relative to the entire amount of the resin composition molded body 10. The content ratio of the non-low-melting-point resin particles 13 may be within the range of 15 mass% or more and 75 mass% or less, and may be within the range of 30 mass% or more and 60 mass% or less. If the resin composition molded body 10 does not contain the non-low-melting-point resin particles 13, the waste-derived recycled resin containing the non-low-melting-point resin cannot be utilized as the resin raw material for the resin composition molded body 10. Thus, it cannot contribute to reduction in CO 2 emission due to incineration of the waste containing the non-low-melting-point resin.

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

[0023] A total content 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 lower than or higher than the content of the resin base material 11. For example, when the content ratio of the low-melting-point resin contained in the resin base material 11 is represented by X (unit: mass%), the content ratio of the non-low-melting-point resin particles 13 is represented by Y (unit: mass%), and the content ratio of the cellulose-based material particles 12 is represented by Z (unit: mass%), a difference between the particle content (Y+Z) and the low-melting-point resin, (Y+Z)-X, may satisfy the following formula (1), for example. Y + Z − X ≥ − 10

[0024] The (Y+Z)-X may also satisfy the following formula (2). 79 ≥ Y + Z − X ≥ 1

[0025] The resin composition molded body 10 of the present embodiment may further contain an additive. As the additive, various additives applied for conventional wood plastic, such as a compatibilizer, a pigment, a weather-resistance improver, a lubricant, a thermal stabilizer, a filler, a foaming agent, and an antistatic agent, may be used. A content ratio of the additive is within the range of, for example, 3 mass% or more and 10 mass% or less as a content ratio relative to the entire amount of the resin composition molded body 10. The additive may be melted in the resin base material 11, or may be dispersed in the resin base material 11.

[0026] The resin composition molded body 10 of the present embodiment may contain an inevitable impurity. The inevitable impurity refers to an impurity inevitably mixed in the raw material or the producing process. Examples of the inevitable impurity include aluminum derived from aluminum-deposited plastic contained in the waste plastic used as the raw material for the low-melting-point resin and non-low-melting-point resin particles 13. A content ratio of aluminum relative to the entire amount of the resin composition molded body 10 may be, for example, less than 1 mass%, may be less than 0.5 mass%, and may be less than 0.2 mass%.

[0027] In the resin composition molded body 10 of the present embodiment having the configuration as above, the content ratio of the low-melting-point resin contained in the resin base material 11 is within the above range. Thus, the resin composition molded body 10 can be produced at a heating temperature of, for example, lower than 190°C, which allows the cellulose-based material particles 12 and the non-low-melting-point resin particles 13 to be dispersed in the resin base material 11 while inhibiting volatilization of the low-molecular-weight components contained in the low-melting-point resin, the non-low-melting-point resin, and the cellulose-based material. Thus, the cellulose-based material particles 12 and the non-low-melting-point resin particles 13 is less likely to absorb water. Accordingly, the resin composition molded body 10 of the present embodiment is less likely to produce foam on the surface, and exhibits excellent water resistance even when produced by using the waste-derived recycled resin containing the non-low-melting-point resin such as the high-melting-point resin and the thermosetting resin. Using the recycled resin containing the non-low-melting-point resin can contribute to reduction in CO 2 emission due to incineration of the waste. The resin composition molded body 10 of the present embodiment has, as an index indicating water resistance, an equilibrium expansion coefficient of 20% or less, specifically 10% or less. The equilibrium expansion coefficient is measured by the following measuring method, for example.(Measuring method)

[0028] The resin composition molded body 10 is immersed in warm water adjusted at 60°C until a rate of change in a thickness of the resin composition molded body 10 per day reaches 0.5% or less. A thickness of the resin composition molded body 10 when the rate of change in the thickness reaches 0.5% or less is set as Tf (unit: mm) and a thickness of the resin composition molded body 10 before immersion in the warm water is set as Ti (unit: mm), and the equilibrium expansion coefficient is calculated by using the following formula (3). Equilibrium expansion coefficient % = Tf − Ti / Ti × 100

[0029] In the resin composition molded body 10 of the present embodiment, the cellulose-based material particles 12 have the particle diameter within the above range, and the content ratio in the resin composition molded body 10 is within the above range. Thus, the texture of the resin composition molded body 10 due to the cellulose-based material particles 12 is improved. For example, when the cellulose-based material particles 12 are the wood powder particles, the resin composition molded body 10 has excellent wood texture. Further, since the content ratio of the non-low-melting-point resin particles 13 in the resin composition molded body 10 is within the above range, the high-melting-point resin and the thermosetting resin that are often subjected to incineration can be effectively used, which significantly contributes to reduction in CO 2 emission due to incineration of waste.

[0030] As for the cellulose-based material particles 12 in the resin composition molded body 10 of the present embodiment, when the content ratio of the particles having a major axis of 3.0 mm or more among particles having a major axis of 1.0 mm or more is 35 number % or less, the particle diameters of the cellulose-based material particles 12 are small, and the surfaces of the cellulose-based material particles 12 are easily covered with the low-melting-point resin. Thus, the likelihood that the cellulose-based material particles 12 are fallen from the resin composition molded body 10 and absorb water is reduced, and water resistance of the resin composition molded body 10 is improved. In addition, when the cellulose-based material particles 12 are particles passed through a sieve having an aperture size of 3 mm, the likelihood of mixing of coarse cellulose-based material particles 12 is reduced, and thus, the surfaces of the cellulose-based material particles 12 can be more reliably covered with the low-melting-point resin.

[0031] As for the non-low-melting-point resin particles 13 in the resin composition molded body 10 of the present embodiment, when the content ratio of the particles having a major axis of 3.0 mm or more among particles having a major axis of 1.0 mm or more is 35 number % or less, the particle diameters of the non-low-melting-point resin particles 13 are small, and the surfaces of the non-low-melting-point resin particles 13 are easily covered with the low-melting-point resin. Thus, the likelihood that the non-low-melting-point resin particles 13 are fallen from the resin composition molded body 10 is reduced. In addition, when the non-low-melting-point resin particles 13 are particles passed through a sieve having an aperture size of 3 mm, the likelihood of mixing of coarse non-low-melting-point resin particles 13 is reduced, and thus, the surfaces of the non-low-melting-point resin particles 13 can be more reliably covered with the low-melting-point resin.

[0032] In the resin composition molded body 10 of the present embodiment, when the ratio of the content ratio of the cellulose-based material particles 12 relative to the content ratio of the low-melting-point resin contained in the resin base material 11 is 3.0 or less, the surfaces of the cellulose-based material particles 12 can be further reliably covered with the low-melting-point resin.

[0033] In the resin composition molded body 10 of the present embodiment, when the low-melting-point resin contained in the resin base material 11 contains polyethylene having a melting point of lower than 160°C and polypropylene having a melting point of 160°C or higher, flowability of the resin base material 11 due to heating is improved. Thus, the cellulose-based material particles 12 and the non-low-melting-point resin particles 13 can be more uniformly dispersed, and more difficult to produce foam. When the mass ratio of polyethylene relative to polypropylene is 1.4 or less, the effect by using polyethylene and polypropylene in combination can be more reliably obtained.

[0034] The resin composition molded body 10 of the present embodiment can be utilized as, for example, a civil engineering material, a building material, and a horticultural material. Examples of the civil engineering material include a paving material. Examples of the building material include a flooring material, specifically a flooring material for a bathroom, a roof material, a wall material, a handrail, a sash, a wood deck, and a fence. Examples of the horticultural material include a flower bed. Since having excellent water resistance, the resin composition molded body 10 is particularly useful as the paving material and the building material that are used outdoors. In addition, the resin composition molded body 10 containing the wood powder particles in which the cellulose-based material particles 12 are the wood powder particles can be used as wood plastic. A shape of the resin composition molded body 10 is not particularly limited, and may be a block shape, a plate shape, or a column shape according to the purpose of use.

[0035] Next, one embodiment of the paving material using the resin composition molded body 10 of the present embodiment will be described. As illustrated in FIG. 2, a paving material 20 of the present embodiment has a square plate shape in a front view. A surface 21 of the paving material 20 has a plurality of projections extending in parallel to each other. The paving material 20 has a tongue 22 on one side face of a pair of side faces facing each other, and has a groove 23 on the other side face.

[0036] As illustrated in FIG. 3, the paving material 20 is laid over a stacked body which is formed in a region surrounded by curb blocks 32 on a subgrade 31 and in which a concrete slab 33 and a leveling material 34 are stacked in this order. The concrete slab 33 has a reinforcement bar therein. As the leveling material 34, mortar or sprinkled sand may be used.

[0037] The paving material 20 is bonded by fitting the tongue 22 and the groove 23. Rainwater during rainfall flows toward the outside passing between the tongue 22 and the groove 23 of the paving material 20. Thus, the likelihood that rainwater gathers on the surface 21 side of the paving material 20 is reduced.

[0038] Next, a method for producing the resin composition molded body 10 of the present embodiment will be described. The resin composition molded body 10 can be produced by, for example, a method including: a preparing step of preparing a raw material composition powder; and a forming step of forming the resin composition molded body 10 by using the raw material composition powder.

[0039] The raw material composition powder prepared in the preparing 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 contain a low-melting-point resin having a melting point within the range of 80°C or higher and lower than 190°C. The low-melting-point resin particles may be particles passed through a sieve having an aperture size of 3 mm. A content ratio of the low-melting-point resin is within the range of 10 mass% or more and 80 mass% or less as a content ratio relative to the entire amount of the raw material composition powder. The cellulose-based material particles may be particles passed through a sieve having an aperture size of 3 mm. A content ratio of the cellulose-based material particles is within the range of 20 mass% or more and 50 mass% or less as a content ratio relative to the entire amount of the raw material composition powder. The non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin. The non-low-melting-point resin particles may be particles passed through a sieve having an aperture size of 3 mm. A content ratio of the non-low-melting-point resin particles is within the range of 10 mass% or more and 80 mass% or less as a content ratio relative to the entire amount of the raw material composition powder.

[0040] The raw material composition powder can be produced by, for example, a method of mixing the low-melting-point resin particles, the cellulose-based material particles, and the non-low-melting-point resin particles at a ratio such that the content rates are within the above ranges. The raw material composition powder can also be produced by, for example, a method of mixing lumps of the low-melting-point resin, lumps of the cellulose-based material, and lumps of the non-low-melting-point resin particles at a ratio such that the content rates are within the above ranges, crushing the obtained mixture, and then sieving the crushed product by using a sieve having an aperture size of 3 mm or less.

[0041] Particle sizes of the cellulose-based material particles and the non-low-melting-point resin particles in the raw material composition powder may contain particles with less than 1.0 mm within the range of 10 number % or more and 85 number %, particles with 1.0 mm or more and less than 2.0 mm within the range of 15 number % or more and 50 number % or less, particles with 2.0 mm or more and less than 3.0 mm within the range of 0 number % or more and 40 number % or less, and particles with 3.0 mm or more within the range of 0 number % or more and 30 number % or less.

[0042] In the forming step, the raw material composition powder is heated and kneaded at a temperature equal to or higher than the melting point of the low-melting-point resin particles and lower than 190°C. The kneading temperature may be 150°C or higher, and may be within the range of 165°C or higher and 180°C or lower. The heating and kneading generate a melted product in which the low-melting-point resin particles in the raw material composition powder are melted. Then, the generated melted product is molded into a target shape. As the method for molding the melted product, various methods used as a method for molding a thermoplastic resin, such as extrusion molding and injection molding, can be used.

[0043] According to the method for producing the resin composition molded body 10 of the present embodiment having the above configuration, the low-molecular-weight components contained in the raw material composition powder are less likely to volatilize because the kneading temperature in the forming step is within the above range. Thus, the obtained resin composition molded body 10 is less likely to produce foam. In the method for producing the resin composition molded body 10 of the present embodiment, when the particle sizes of the cellulose-based material particles and the non-low-melting-point resin particles are within the above ranges, the resin composition molded body 10 having uniform composition and high water resistance can be obtained even without pelletizing the raw material composition powder before the forming step. Note that the raw material composition powder may be pelletized before the forming step in the method for producing the resin composition molded body 10 of the present embodiment.EXAMPLES

[0044] Hereinafter, the present disclosure will be described in more detail based on Examples. The present disclosure is not limited by these Examples. In the present Examples, the following low-melting-point resin, wood chip, and non-low-melting-point resin were used as raw materials. Low-melting-point resin (PE powder): Powder in which polyethylene separated and recovered from waste plastic collected in accordance with The Containers and Packaging Recycling Act was crushed (melting point: 150°C). Low-melting-point resin powder (PP powder): Powder in which polypropylene separated and recovered from waste plastic collected in accordance with The Containers and Packaging Recycling Act was crushed (melting point: 160°C). Non-low-melting-point resin powder (PET powder): Powder in which polyethylene terephthalate separated and recovered from waste plastic collected in accordance with The Containers and Packaging Recycling Act was crushed and sieved with a sieve having an aperture size of 1 mm, 2 mm, or 3 mm (melting point: 250°C). Wood powder: Powder in which building waste wood separated from a building waste material was crushed and sieved with a sieve having an aperture size of 1 mm, 2 mm, or 3 mm.

[0045] The following Table 1 shows particle size distributions of the PET powder and the wood powder sieved with the sieve having an aperture size of 1 mm, 2 mm, or 3 mm. In Table 1, 1-mm sieved product, 2-mm sieved product, and 3-mm sieved product respectively refer to the sieved products with the sieves having an aperture size of 1 mm, 2 mm, or 3 mm. The particle size distributions of the PET powder and the wood powder were obtained by measuring major axes of 1000 particles by using a microscope and an image size measuring apparatus to calculate each of number % of particles with less than 1.0 mm, number % of particles with 1.0 mm or more and less than 2.0 mm, number % of particles with 2.0 mm or more and less than 3.0 mm, and number % of particles with 3.0 mm or more. Note that the particle size distributions of the PET powder and the wood powder were each measured three times. [Table 1]PET powder (number %)Wood powder (number %)less than 1.0 mm1.0 mm or more and less than 2.0 mm2.0 mm or more and less than 3.0 mm3.0 mm or moreless than 1.0 mm1.0 mm or more and less than 2.0 mm2.0 mm or more and less than 3.0 mm3.0 mm or more1-mm sieved product8017306822737918216918857820206524922-mm sieved product3445165324018103841147314216113938194274118143-mm sieved product132935231729282611273824153125291425392218243424 [Example 1]

[0046] Prepared was a raw material composition powder in which 10 parts by mass of the PE powder, 5 parts by mass of the PP powder, 50 parts by mass of the PET powder (2-mm sieved product), and 30 parts by mass of the wood powder (2-mm sieved product) were mixed at this ratio. Mixing 90 parts by mass of this raw material composition powder and 10 parts by mass of additives was performed, and the obtained mixture was fed into an extrusion molder to produce a paving material illustrated in FIG. 2 under a condition of a kneading molding temperature of 165°C. As the additives, a compatibilizer, a pigment, a weather-resistance improver, a lubricant, and a thermal stabilizer were used. The obtained paving material was a plate product with 300 mm in length × 300 mm in width × 30 mm in thickness. Content rates of the low-melting-point resins (PE, PP), the non-low-melting-point resin (PET), the wood powder, and the additives in the obtained paving material were the same as the blending rates of the raw materials.[Examples 2 to 15 and Comparative Examples 1 to 5]

[0047] Raw material composition powders were produced in the same manner as in Example 1 except that: the blending rates of the PE powder, the PP powder, the PET powder, and the wood powder were changed to rates shown in the following Table 2; and the types of the PET powder and the wood powder were changed to the types shown in the following Table 2. Then, paving materials were produced by using the obtained raw material composition powders in the same manner as in Example 1 except that the kneading molding temperature of the extrusion molder was set to a temperature shown in the following Table 2. In Comparative Example 3, the non-low-melting-point resin was not used.[Evaluation]

[0048] The ratio of the non-low-melting-point resin, appearance (wood texture and foaming), and water resistance (an equilibrium expansion coefficient) of the obtained paving materials were evaluated as follows. Table 2 shows the results.<Ratio of non-low-melting-point resin>

[0049] The ratio of the non-low-melting-point resin in the paving material was calculated. A case where the ratio of the non-low-melting-point resin was more than 10 mass% was evaluated as "A", and a case where the ratio was 10 mass% or less was evaluated as "B".<Appearance (wood texture and foaming)>

[0050] The plane of the paving material was visually observed. The wood texture was observed visually. A case where there were a change in color from thin to thick brown and the wood texture was evaluated as "A", a case where the color was only thick brown and there was the wood texture was evaluated as "B", and a case where the color was only thick brown and there was no wood texture was evaluated as "C". The foaming was evaluated by measuring expansion in the thickness direction immediately after the paving material was taken out of the mold of the extrusion molder. A case where the expansion was less than 0.5 mm was evaluated as "A", a case where the expansion was 0.5 mm or more and less than 2.0 mm was evaluated as "B", and a case where the expansion was 2.0 mm or more was evaluated as "C".<Water resistance (equilibrium expansion coefficient)>

[0051] A paving material was immersed in warm water adjusted at 60°C. The paving material was taken out of the warm water on a daily basis to measure a thickness of the paving material. A rate of change in the thickness of the paving material relative to the thickness of the paving material in the previous day was calculated by the following formula.

[0052] When the rate of change in the thickness of the paving material reached 0.5% or less, the expansion coefficient of the thickness of the paving material due to water absorption was regarded to reach the equilibrium, and the equilibrium expansion coefficient of the thickness of the paving material was calculated by using the following formula (3). Note that the thickness of the paving material was an average of thicknesses at five positions in total of the center portion and portions each near the four corners on the plane. Equilibrium expansion coefficient (%) = {(Tf-Ti) / Ti} × 100 (3)

[0053] In the formula (3), Tf (unit: mm) represents the thickness of the resin composition molded body when the rate of change in the thickness reaches 0.5% or less, and Ti (unit: mm) represents the thickness of the resin composition molded body before immersion in the warm water. As for the water resistance, a case where the equilibrium expansion coefficient was 10% or less was evaluated as "A", a case where the equilibrium expansion coefficient was more than 10% and 20% or less was evaluated as "B", and a case where the equilibrium expansion coefficient was more than 20% was evaluated as "C". [Table 2]Producing conditionEvaluationBlending composition of raw materialsKneading forming temperature (°C)Ratio of low-melting-point resinAppearanceWater resistanceBlending amount of low-melting-point resin powder (parts by mass)Non-low-melting-point resin powder (PET powder)Wood powderBlending amount of additive (parts by mass)Wood powder / low-melting-point resin powder (mass ratio)Wood textureFoamingPE powderPP powderTotalTypeBlending amount (parts by mass)TypeBlending amount (parts by mass)Example 1105152-mm sieved product502-mm sieved product30102.0165AAAAExample 2510152-mm sieved product502-mm sieved product30102.0165AAAAExample 355102-mm sieved product602-mm sieved product20102.0165AAAAExample 41515302-mm sieved product202-mm sieved product40101.3165AAAAExample 52020402-mm sieved product202-mm sieved product30100.8165AAAAExample 62525502-mm sieved product102-mm sieved product30100.6165BAAAExample 755102-mm sieved product502-mm sieved product30103.0165AAABExample 855101-mm sieved product601-mm sieved product20102.0165AAAAExample 91515303-mm sieved product203-mm sieved product40101.3165AAABExample 103535701-mm sieved product101-mm sieved product10100.1165BBAAExample 112525501-mm sieved product301-mm sieved product10100.2165ABAAExample 1255101-mm sieved product401-mm sieved product40104.0165AAAAExample 1355101-mm sieved product301-mm sieved product50105.0165AAABExample 141515301-mm sieved product101-mm sieved product50101.7165BAAAExample 153535702-mm sieved product103-mm sieved product10100.1165BCAAComparative Example 15051-mm sieved product651-mm sieved product20104.0150AAACComparative Example 20551-mm sieved product651-mm sieved product20104.0165AAACComparative Example 3353570-01-mm sieved product20100.3165CAAAComparative Example 455101-mm sieved product201-mm sieved product60106.0165AAAC

[0054] From the results shown in Table 2, it was understood that the paving material having the content rates of the low-melting-point resin, the non-low-melting-point resin particles, and the wood powder particles within the ranges of the present disclosure had excellent appearance and water resistance. Thus, this paving material can be advantageously used as the paving material used outdoors. In particular, the paving materials obtained in Examples 1 to 6 using the 2-mm sieved product as the wood powder and having the ratio of the wood powder / the low-melting-point resin of 2.0 or less and Examples 8, 10 to 12, and 14 using the 1-mm sieved product as the wood powder and having the ratio of the wood powder / the low-melting-point resin of 4.0 or less exhibited the water resistance of A (the equilibrium expansion coefficient in the warm water at 60°C of 10% or less), which exhibited excellent water resistance.

[0055] In contrast, the paving materials obtained in Comparative Examples 1 and 2 having the low content ratio of the low-melting-point resin compared with the range of the present disclosure exhibited the water resistance of C (the equilibrium expansion coefficient in the warm water at 60°C of more than 20%). This is because the low content ratio of the low-melting-point resin causes some wood powder particles not to be covered with the low-melting-point resin and to facilitate absorption of the warm water. Comparative Example 3 using no non-low-melting-point resin exhibited excellent water resistance, but cannot contribute to reduction in CO 2 emission due to incineration of waste containing the non-low-melting-point resin. Comparative Example 4 having the high content ratio of the wood powder compared with the range of the present disclosure exhibited the water resistance of C. This is because the high content ratio of the wood powder facilitates absorption of the warm water.[Comparative Example 5]

[0056] A paving material was produced in the same manner as in Example 3 except that the kneading molding temperature of the extrusion molder was changed to 200°C. The obtained paving material exhibited the evaluation result of foaming of C. This is because the low-molecular-weight components contained in the raw material composition powder volatilize to produce foam on the surface of the paving material.

[0057] The aspects of the present disclosure will be described in the following additional remarks.(Additional Remark 1)

[0058] A resin composition molded body that is a molded body of a composition comprising: a resin base material containing a low-melting-point resin; cellulose-based material particles dispersed in the resin base material; and non-low-melting-point resin particles dispersed in the resin base material, wherein the low-melting-point resin has a melting point of 80°C or higher and lower than 190°C, and a content ratio of the low-melting-point resin relative to an entire amount of the composition is 10 mass% or more and 80 mass% or less, the cellulose-based material particles contain at least wood powder particles, a content ratio of the cellulose-based material particles relative to the entire amount of the composition is 10 mass% or more and 50 mass% or less, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin, and a content ratio of the non-low-melting-point resin particles relative to the entire amount of the composition is 10 mass% or more and 80 mass% or less.(Additional Remark 2)

[0059] The resin composition molded body according to Additional Remark 1, wherein each of the cellulose-based material particles and the non-low-melting-point resin particles has a content ratio of particles having a major axis of 3.0 mm or more, among particles thereof having a major axis of 1.0 mm or more, of 35 number % or less.(Additional Remark 3)

[0060] The resin composition molded body according to Additional Remark 2, wherein the content ratio of the particles having a major axis of 3.0 mm or more is 20 number % or less.(Additional Remark 4)

[0061] The resin composition molded body according to any one of Additional Remarks 1 to 3, wherein the cellulose-based material particles and the non-low-melting-point resin particles are particles passed through a sieve having an aperture size of 3 mm.(Additional Remark 5)

[0062] The resin composition molded body according to Additional Remark 4, wherein the cellulose-based material particles and the non-low-melting-point resin particles are particles passed through a sieve having an aperture size of 2 mm.(Additional Remark 6)

[0063] The resin composition molded body according to any one of Additional Remarks 1 to 5, wherein a ratio of the content ratio of the cellulose-based material particles relative to the content ratio of the low-melting-point resin (the cellulose-based material particles / the low-melting-point resin) is 5.0 or less.(Additional Remark 7)

[0064] The resin composition molded body according to Additional Remark 6, wherein the ratio of the content ratio of the cellulose-based material particles relative to the content ratio of the low-melting-point resin (the cellulose-based material particles / the low-melting-point resin) is 3.0 or less.(Additional Remark 8)

[0065] The resin composition molded body according to Additional Remark 7, wherein the ratio of the content ratio of the cellulose-based material particles relative to the content ratio of the low-melting-point resin (the cellulose-based material particles / the low-melting-point resin) is 2.5 or less.(Additional Remark 9)

[0066] The resin composition molded body according to any one of Additional Remarks 1 to 8, wherein the low-melting-point resin contains at least two types of resins.(Additional Remark 10)

[0067] The resin composition molded body according to Additional Remark 9, wherein the low-melting-point resin contains at least polyethylene and polypropylene.(Additional Remark 11)

[0068] The resin composition molded body according to Additional Remark 10, wherein a mass ratio of a content of the polyethylene relative to a content of the polypropylene is 1.4 or less.(Additional Remark 12)

[0069] The resin composition molded body according to Additional Remark 11, wherein the mass ratio of the content of the polyethylene relative to the content of the polypropylene is 1.2 or less.(Additional Remark 13)

[0070] The resin composition molded body according to any one of Additional Remarks 1 to 12, wherein the content ratio of the low-melting-point resin is 10 mass% or more and 50 mass% or less.(Additional Remark 14)

[0071] The resin composition molded body according to any one of Additional Remarks 1 to 13, wherein the content of the non-low-melting-point resin particles is equal to or higher than the content of the low-melting-point resin.(Additional Remark 15)

[0072] The resin composition molded body according to any one of Additional Remarks 1 to 14, wherein the content ratio of the non-low-melting-point resin particles is 15 mass% or more and 75 mass% or less.(Additional Remark 16)

[0073] The resin composition molded body according to Additional Remark 15, wherein the content ratio of the non-low-melting-point resin particles is 30 mass% or more and 60 mass% or less.(Additional Remark 17)

[0074] The resin composition molded body according to any one of Additional Remarks 1 to 16, wherein a content ratio of aluminum relative to the entire amount of the composition is less than 1 mass%.(Additional Remark 18)

[0075] The resin composition molded body according to any one of Additional Remarks 1 to 17, wherein (Y+Z)-X satisfies the following formula (1), wherein X (unit: mass%) represents the content ratio of the low-melting-point resin, Y (unit: mass%) represents the content ratio of the non-low-melting-point resin particles, and Z (unit: mass%) represents the content ratio of the cellulose-based material particles. Y + Z − X ≥ − 10(Additional Remark 19)

[0076] The resin composition molded body according to Additional Remark 18, wherein the (Y+Z)-X satisfies the following formula (2). 79 ≥ Y + Z − X ≥ 1(Additional Remark 20)

[0077] The resin composition molded body according to any one of Additional Remarks 1 to 19 having an equilibrium expansion coefficient measured by the following measuring method of 20% or less.(Measuring method)

[0078] the resin composition molded body is immersed in warm water adjusted at 60°C until a ratio of change in a thickness of the resin composition molded body per day reaches 0.5% or less, a thickness of the resin composition molded body when the ratio of change in the thickness reaches 0.5% or less is set as Tf (unit: mm) and a thickness of the resin composition molded body before immersion in the warm water is set as Ti (unit: mm), and the equilibrium expansion coefficient is calculated by using the following formula (3). Equilibrium expansion coefficient % = Tf − Ti / Ti × 100(Additional Remark 21)

[0079] The resin composition molded body according to Additional Remark 20, wherein the equilibrium expansion coefficient is 10% or less.(Additional Remark 22)

[0080] The resin composition molded body according to any one of Additional Remarks 1 to 21 having a block shape, a plate shape, or a column shape.(Additional Remark 23)

[0081] A civil engineering material, comprising the resin composition molded body according to any one of Additional Remarks 1 to 22.(Additional Remark 24)

[0082] A building material, comprising the resin composition molded body according to any one of Additional Remarks 1 to 22.(Additional Remark 25)

[0083] A horticultural material, comprising the resin composition molded body according to any one of Additional Remarks 1 to 22.(Additional Remark 26)

[0084] A method for producing a resin composition molded body, the method comprising: preparing a raw material composition powder that is a powder of a composition comprising low-melting-point resin particles derived from waste, cellulose-based material particles, and non-low-melting-point resin particles derived from waste, wherein the low-melting-point resin particles contain a low-melting-point resin having a melting point of 80°C or higher and lower than 190°C, and a content ratio of the low-melting-point resin relative to an entire amount of the composition is 10 mass% or more and 80 mass% or less, a content ratio of the cellulose-based material particles relative to the entire amount of the composition is 10 mass% or more and 50 mass% or less, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin, and a content ratio of the non-low-melting-point resin particles relative to the entire amount of the composition is 10 mass% or more and 80 mass% or less; and heating and kneading the raw material composition powder at a temperature equal to or higher than the melting point of the low-melting-point resin particles and lower than 190°C.(Additional Remark 27)

[0085] The method for producing a resin composition molded body according to Additional Remark 26, wherein the cellulose-based material particles and the non-low-melting-point resin particles are particles passed through a sieve having an aperture size of 3 mm.EXPLANATION OF REFERENCE NUMERALS

[0086] 10: Resin composition molded body, 11: Resin base material, 12: Cellulose-based material particles, 13: Non-low-melting-point resin particles, 20: Paving material, 21: Surface, 22: Tongue, 23: Groove, 31: Subgrade, 32: Curb block, 33: Concrete slab, 34 Leveling material

Claims

1. A resin composition molded body that is a molded body of a composition comprising: a resin base material containing a low-melting-point resin; cellulose-based material particles dispersed in the resin base material; and non-low-melting-point resin particles dispersed in the resin base material, wherein the low-melting-point resin has a melting point of 80°C or higher and lower than 190°C, and a content ratio of the low-melting-point resin relative to an entire amount of the composition is 10 mass% or more and 80 mass% or less, the cellulose-based material particles contain at least wood powder particles, a content ratio of the cellulose-based material particles relative to the entire amount of the composition is 10 mass% or more and 50 mass% or less, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin, and a content ratio of the non-low-melting-point resin particles relative to the entire amount of the composition is 10 mass% or more and 80 mass% or less.

2. The resin composition molded body according to claim 1, wherein each of the cellulose-based material particles and the non-low-melting-point resin particles has a content ratio of particles having a major axis of 3.0 mm or more, among particles thereof having a major axis of 1.0 mm or more, of 35 number % or less.

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

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

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

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

7. The resin composition molded body according to claim 6, wherein a mass ratio of a content of the polyethylene relative to a content of the polypropylene is 1.4 or less.

8. The resin composition molded body according to any one of claims 1 to 7, wherein the content ratio of the low-melting-point resin is 10 mass% or more and 50 mass% or less.

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

10. The resin composition molded body according to any one of claims 1 to 9 having a block shape, a plate shape, or a column shape.

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

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

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

14. A method for producing a resin composition molded body, the method comprising: preparing a raw material composition powder that is a powder of a composition comprising low-melting-point resin particles derived from waste, cellulose-based material particles, and non-low-melting-point resin particles derived from waste, wherein the low-melting-point resin particles contain a low-melting-point resin having a melting point of 80°C or higher and lower than 190°C, and a content ratio of the low-melting-point resin relative to an entire amount of the composition is 10 mass% or more and 80 mass% or less, a content ratio of the cellulose-based material particles relative to the entire amount of the composition is 10 mass% or more and 50 mass% or less, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin having a melting point of 190°C or higher and a thermosetting resin, and a content ratio of the non-low-melting-point resin particles relative to the entire amount of the composition is 10 mass% or more and 80 mass% or less; and heating and kneading the raw material composition powder at a temperature equal to or higher than a melting point of the low-melting-point resin particles and lower than 190°C.

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

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