Resin composition molded body and resin composition pellet

Abstract

A resin composition molded body according to one embodiment of the present disclosure comprises: a resin base material that contains a low-melting-point resin; non-low-melting-point resin particles that are dispersed in the resin base material; and cellulose-based material particles that are dispersed in the resin base material. The low-melting-point resin has a melting point within the range of not lower than 80°C but lower than 190°C, and contains at least a polystyrene. The non-low-melting-point resin particles contain one or both of a thermosetting resin and a high-melting-point resin that has a melting point of 190°C or higher. The content of the low-melting-point resin with respect to the composition is within the range of 15-80 mass%, the content of polystyrene with respect to the composition is 1 mass% or higher, the content of the non-low-melting-point resin particles with respect to the composition is within the range of 10-65 mass%, and the content ratio of the cellulose-based material particles to the low-melting-point resin is within the range of 0.1-3.0.

Description

Resin composition molded article and resin composition pellets

[0001] The present disclosure relates to a resin composition molded article and resin composition pellets.

[0002] A resin composition molded article in which wood powder particles are dispersed in a resin (matrix material) is known (see, for example, Patent Document 1). A resin composition molded article containing wood powder particles is also called wood plastic, and has advantages such as being less prone to corrosion, less prone to cracking, less prone to splintering, and being lighter in weight compared to wood, while having a texture close to that of wood. For this reason, resin composition molded articles containing wood powder particles are widely used as materials for construction materials and the like. Resin composition molded articles containing wood powder particles are generally produced by heat-molding a raw material composition containing wood powder particles and a thermoplastic resin. The use of recycled resin separated and recovered from waste as a raw material for thermoplastic resins has been studied (see, for example, Patent Document 2).

[0003] Japanese Patent Application Laid-Open No. 2015-529582, Japanese Patent Application Laid-Open No. 2001-353707

[0004] The use of waste-derived recycled resin as a resin raw material for resin composition molded articles promotes resource circulation and reduces CO from waste incineration ２ It is desirable from the viewpoint of greatly contributing to the reduction of emissions. On the other hand, wood plastics used as substitutes for wood are desired to have high bending strength and bending elastic modulus so as to withstand loads and impacts. Furthermore, wood plastics used outdoors such as paving materials and deck materials are required to have high water resistance and be less prone to deterioration due to rainwater, as well as high heat resistance and be less prone to deterioration due to heat. However, according to studies conducted by the inventors of the present disclosure, resin composition molded articles produced using waste-derived recycled resin tend to easily have fluctuations in properties such as bending strength, bending elastic modulus, water resistance, and heat resistant temperature.

[0005] An object of the present disclosure is to provide a resin composition molded article, a paving material and a deck material that are excellent in bending strength, bending elastic modulus, water resistance and heat resistant temperature even when recycled resin is used, and resin composition pellets that can be used as a raw material for producing the molded article.

[0006] The resin composition molded article of the present disclosure is a molded article of a composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

[0007] This is a cross-sectional view of a molded resin composition according to one embodiment of the present disclosure. This is a perspective view of an example of a paving material according to one embodiment of the present disclosure. This is a cross-sectional view of a road surface paved using the paving material according to one embodiment of the present disclosure. This is a perspective view of another example of a paving material according to one embodiment of the present disclosure. This is a perspective view of yet another example of a paving material according to one embodiment of the present disclosure. This is a perspective view of an example of a decking material according to one embodiment of the present disclosure. This is a perspective view of a deck structure using the decking material according to one embodiment of the present disclosure.

[0008] The embodiments of this disclosure will be described in detail below with reference to the drawings.

[0009] [First Embodiment] Figure 1 is a cross-sectional view of a resin composition molded article according to one embodiment of the present disclosure. 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 and fillers dispersed in the resin substrate 11. The fillers include non-low melting point resin particles 12 and cellulose-based material particles 13. Inorganic particles may also be included as fillers.

[0010] 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 higher and less than 190°C. The low-melting-point resin can be any resin that melts at less than 190°C, and does not need to have a melting point. The low-melting-point resin includes polystyrene. Polystyrene is not limited to polystyrene, but atactic polystyrene is preferred.

[0011] The low-melting-point resin may be polystyrene alone or a mixture of polystyrene and a low-melting-point resin other than polystyrene. Examples of low-melting-point resins other than polystyrene include polyolefin resins such as polyethylene (PE) and polypropylene (PP), acrylonitrile-butadiene-styrene resin (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide 12 (PA12), and polyacetal (POM). The low-melting-point resin other than polystyrene may be used individually or in combination of two or more. The low-melting-point resin other than polystyrene is preferably a polyolefin resin. The polyolefin resin preferably contains at least one of polypropylene and polyethylene. When both polypropylene and polyethylene are included, the polyethylene content ratio (polyethylene / polypropylene) may be 2.0 or less by mass, 1.5 or less, or 1.0 or less.

[0012] The low-melting-point resin may be a recycled resin derived from waste. For example, the low-melting-point resin may be a low-melting-point resin separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law.

[0013] The content of the low-melting-point resin in the composition is within the range of 10% by mass or more and 80% by mass or less. The content of the low-melting-point resin may 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, within the range of 15% by mass or more and 45% by mass or less, or within the range of 20% by mass or more and 45% by mass or less.

[0014] The polystyrene content in the composition is 1% by mass or more. The polystyrene content in the composition may be 5% by mass or more, 80% by mass or less, 50% by mass or less, 35% by mass or less, or 20% by mass or less. If the low-melting-point resin contains a resin other than polystyrene, the polystyrene content ratio to the resin other than polystyrene may be in the range of 0.1 to 10, 0.15 to 8, 0.25 to 6, or 0.25 to 4.

[0015] The non-low melting point resin particles 12 dispersed in the resin substrate 11 include either or both a high melting point resin and a thermosetting resin. The high melting point resin is a thermoplastic resin with 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 high melting point resins 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 thermosetting resins include polyimide (PI), polyurethane (PU), and phenolic resin (PF).

[0016] The particle shape of the non-low melting point resin particles 12 is not particularly limited and may be spherical, ellipsoidal, cylindrical, prismatic, plate-like, or irregularly shaped. The particle size of the non-low melting point resin 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. The content of particles with a major axis of less than 2 mm may be 30 percent or more, or 50 percent or less. The content of non-low melting point resin particles 12 with a major axis of 5.0 mm or more is 1.0 particles / 100 mm as the average content contained in a 10 mm × 10 mm cross-section of the resin composition molded body 10. ２ The following is also acceptable: 0.5 pieces / 100 mm ２ The following is also acceptable.

[0017] The non-low melting point resin particles 12 may have passed through a sieve with a mesh size of 3 mm. The non-low melting point resin 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.

[0018] The non-low melting point resin particles 12 may be derived from waste. For example, the non-low melting point resin particles 12 may be pulverized high-melting point resin or thermosetting resin separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law.

[0019] The content of non-low melting point resin particles 12 in the composition is within the range of 10% by mass or more and 65% by mass or less. The content of non-low melting point resin particles 12 in the composition may be within the range of 15% by mass or more and 65% by mass or less, or within the range of 30% by mass or more and 60% by mass or less. The content ratio of non-low melting point resin particles 12 to low melting point resin (non-low melting point resin particles / low melting point resin) may be within the range of 0.10 to 4.50 by mass, within the range of 0.15 to 3.70, or within the range of 0.80 to 2.00. When the content ratio of non-low melting point resin particles / low melting point resin is within this range, the strength and water resistance of the resin composition molded article 10 are improved, so that the resin composition molded article 10 can be used stably for a long period of time even in an outdoor environment. If the resin composition molded body 10 does not contain non-low melting point resin particles 12, recycled resin derived from waste containing non-low melting point resin cannot be used as the resin raw material for the resin composition molded body 10. Therefore, CO2 emissions from the incineration of waste containing non-low melting point resin are reduced. ２ It does not contribute to reducing emissions. From the viewpoint of effective utilization of discarded non-low melting point resins, a higher content of non-low melting point resin particles 12 is preferable.

[0020] The particle shape of the cellulose-based material particles 13 is not particularly limited and may be spherical, ellipsoidal, cylindrical, prismatic, plate-like, or irregular in shape. The particle size of the cellulose-based material particles 13 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 13.

[0021] The content of cellulose-based material particles 13 with a major axis of 5.0 mm or more is 1.0 particles / 100 mm as the average content contained in a 10 mm x 10 mm cross-sectional area of ​​the resin composition molded body 10. ２ The following is also acceptable: 0.5 pieces / 100 mm ２ The following may also be true. The average content of cellulose-based material particles 13 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 13 present in the 1000 regions using an optical microscope.

[0022] The cellulose-based material particles 13 may have passed through a sieve with a mesh size of 3 mm. The cellulose-based material particles 13 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.

[0023] The cellulose-based material particles 13 include at least wood powder particles. The cellulose-based material particles 13 may also include pulp particles as particles other than wood powder particles. The content of wood powder particles in the cellulose-based material particles 13 may be 50% by mass or more, or 80% by mass or more. Furthermore, the cellulose-based material particles 13 may contain wood powder particles alone. Including wood powder particles enhances the wood-like texture of the resin composition molded body 10. From the viewpoint of suppressing the glossiness of the plastic in the resin composition molded body 10 and further emphasizing the wood-like texture, the content of wood powder particles in the composition may be 10% by mass or more. The content of wood powder particles in the composition may be in the range of 10% by mass or more and 45% by mass or in the range of 20% by mass or more and 40% by mass. The cellulose-based material particles 13 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.

[0024] The content ratio of cellulose-based material particles 13 to low-melting-point resin (cellulose-based material particles / low-melting-point resin) is within the range of 0.10 to 3.0. The content ratio of cellulose-based material particles / low-melting-point resin may be within the range of 0.15 to 3.0, or within the range of 0.50 to 2.0.

[0025] As an optional component, inorganic particles dispersed in the resin substrate 11 can include, for example, calcium carbonate, talc, kaolin, glass, and carbon.

[0026] The amount of inorganic particles is, for example, an amount that is within the range of 10% by mass or more and 75% by mass or less as the total content of cellulose-based material particles and inorganic particles in the composition. The amount of inorganic particles in the composition may be within the range of 5% by mass or more and less than 50% by mass, within the range of 7% by mass or more and 40% by mass or less, or within the range of 10% by mass or more and 30% by mass or less.

[0027] The resin composition molded article 10 may further contain additives. Various additives applicable to conventional wood plastics can be used as additives, such as compatibilizers, pigments, weather resistance improvers, lubricants, heat stabilizers, fillers, foaming agents, and antistatic agents. The amount of these additives to be added cannot be uniformly determined as it varies depending on the composition and application of the resin composition molded article 10. However, for example, in the case of a compatibilizer, the amount is within the range of 0.6 parts by mass to 5 parts by mass, based on 100 parts by mass of the composition amount of the resin composition molded article 10 (total amount of resin substrate 11 and filler dispersed in the resin substrate 11). The additive may be melted in the resin substrate 11 or dispersed in the resin substrate 11.

[0028] 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 12. 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.

[0029] The resin composition molded article 10 of this embodiment, having the above configuration, contains low-melting-point resin within the above range, so the fillers (non-low-melting-point resin particles 12, cellulose-based material particles 13) dispersed in the resin substrate 11 are less likely to fall off. Because the resin substrate 11 contains polystyrene within the above range, the hardness of the resin substrate 11 is increased. Because the content of non-low-melting-point resin particles 12 is within the above range, discarded non-low-melting-point resin can be effectively utilized. Because the content of cellulose-based material particles is within the above range, the rigidity is increased. Therefore, even when using recycled resin, the resin composition molded article 10 of this embodiment maintains high levels of flexural strength, flexural modulus, water resistance, and heat resistance.

[0030] In the resin composition molded article 10 of this embodiment, if the polystyrene content is 5% by mass or more, the hardness of the resin substrate 11 becomes higher. If the polystyrene content is 80% by mass or less, the flexural strength, flexural modulus, water resistance, and heat resistance temperature of the resin composition molded article 10 are stabilized at a high level due to the synergistic effect of the non-low melting point resin particles 12 and the cellulose-based material particles 13.

[0031] In the resin composition molded article 10 of this embodiment, if the low-melting-point resin includes a resin other than polystyrene, the low-melting-point resin can be effectively utilized in waste plastics other than polystyrene. Furthermore, if the polystyrene content ratio to the resin other than polystyrene is within the above range, the hardness of the resin substrate 11 can be maintained at a high level.

[0032] In the resin composition molded article 10 of this embodiment, if the cellulose-based material particles 13 include at least wood powder particles, the resin composition molded article 10 has a wood-like texture and can therefore be used as wood plastic.

[0033] In the resin composition molded article 10 of this embodiment, if the particle sizes of the non-low melting point resin particles 12 and the cellulose-based material particles 13 are within the above range, the non-low melting point resin particles 12 and the cellulose-based material particles 13 can be reliably dispersed in the resin substrate 11, making it less likely for the non-low melting point resin particles 12 and the cellulose-based material particles 13 to fall off the resin substrate 11.

[0034] In the resin composition molded article 10 of this embodiment, if inorganic particles are further included, the strength of the resin substrate 11 is improved by the dispersion of inorganic particles in the resin substrate 11. When the total content of cellulose-based material particles 13 and inorganic particles is within the above range, the bending strength and bending modulus of the resin substrate 11 can be improved in a balanced manner.

[0035] In the resin composition molded article 10 of this embodiment, if a compatibilizer is further included within the above range, the fillers (non-low melting point resin particles 12, cellulose-based material particles 13) dispersed in the resin substrate 11 become less likely to fall off. As a result, the stability of the resin composition molded article 10 is improved.

[0036] 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 decking materials, bathroom flooring materials, roofing materials, wall materials, handrails, sashes, fences, skirting boards, cap parts, doors, stairs, baseboards, and lattice materials. 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 13 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. In addition, the resin composition molded body 10 of this embodiment can be used as a transport material such as a transport pallet or as a vehicle material.

[0037] Figure 2 is a perspective view of an example of a paving material according to one embodiment of the present disclosure, and Figure 3 is a cross-sectional view of a road surface paved using that paving material.

[0038] The paving material 20 shown in Figure 2 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.

[0039] In the road surface 30 shown in Figure 3, the paving material 20 is laid on top of a laminate formed by stacking a slab concrete 33 and a leveling material 34 in that order within the area enclosed by the curb blocks 32 of the subgrade 31. The slab concrete 33 has reinforcing bars inside. Mortar or sprinkled sand can be used as the leveling material 34.

[0040] 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.

[0041] FIG. 4 is a perspective view of another example of a paving material according to an embodiment of the present disclosure. The paving material 40 shown in FIG. 4 includes a main body portion 41 having a paired front surface F1 and back surface F2. A plurality of hollow portions 42 are provided in the main body portion 41.

[0042] The plurality of hollow portions 42 are arranged at equal intervals in the width direction W. The hollow portions 42 extend in the length direction L. The hollow portions 42 penetrate the main body portion 41 in the length direction L. Each hollow portion 42 has an inner peripheral surface surrounding the internal space 42a of the hollow portion 42. When viewed in the length direction L, for example, the internal space 42a of the hollow portion 42 has a rectangular shape with the width direction W as the longitudinal direction, and more specifically, has a rounded rectangular shape. In this case, the inner peripheral surface of the hollow portion 42 has a curved surface portion formed in a curved shape. Since the inner peripheral surface of the hollow portion 42 is formed into a curved shape, stress concentration on the angular portions of the inner peripheral surface can be suppressed.

[0043] On the back surface F2 of the main body portion 41, a back-side recess 43 and a small groove portion 44 are formed. If water is present on the surface to be paved by the paving material 40, there is a risk that the paving material 40 absorbs water. By providing the back-side recess 43 in the main body portion 41, contact between the paving material 40 and water on the paved surface can be suppressed. Thereby, water absorption of the paving material 40 can be suitably suppressed.

[0044] FIG. 5 is a perspective view of another example of a paving material according to an embodiment of the present disclosure. The paving material 50 shown in FIG. 5 includes a main body portion 51 having a paired front surface F1 and back surface F2. The main body portion 51 is provided with a plurality of back-side recesses 52 that extend in the length direction L and open toward the lower side T2 in the thickness direction. The back-side recesses 52 are recessed from the back surface F2. Each back-side recess 52 is in the shape of a groove extending in the length direction L. The back-side recesses 52 penetrate the main body portion 51 in the length direction L.

[0045] The plurality of back recesses 52 are arranged at equal intervals in the width direction W. Among the back recesses 52, the central back recess 52 is arranged on the central portion of the main body 51 in the width direction W. Among the back recesses 52, the back recesses 52 at both ends in the width direction W are respectively spaced apart from the end portions of the main body 51 in the width direction. When viewed in the length direction L, the internal space 52a of each back recess 52 each forms an isosceles trapezoidal shape in which the dimension in the width direction W increases toward the upper side in the thickness direction. Each back recess 52 is a dovetail groove. The opening end of each back recess 52 is chamfered respectively.

[0046] The paving material 50 has its back recesses 52 filled with an adhesive, and is fixed to the laying place by the adhesive. Filling the back recesses 52 with the adhesive produces an anchor effect, so the paving material 50 can be firmly fixed to the laying place.

[0047] Fig. 6 is a perspective view of an example of a deck material according to an embodiment of the present disclosure, and Fig. 7 is a perspective view of a deck structure using the deck material.

[0048] The deck material 60 shown in Fig. 6 is a rectangular plate-shaped body in plan view. The surface 61 of the deck material 60 has a plurality of protrusions extending in the longitudinal direction. Inside the deck material 60, a plurality of hollow portions 62 extending in the longitudinal direction are provided.

[0049] The deck structure 70 shown in Fig. 7 includes a plurality of supporting stones 71, supporting posts 72 respectively arranged on the supporting stones 71, a plurality of sleepers 73 arranged at intervals on the upper surfaces of the supporting posts 72, and a plurality of deck materials 60 arranged without gaps on the sleepers 73. The periphery of the deck materials 60 is surrounded by a fascia board 74 arranged in a frame shape. The corners of the fascia board 74 arranged in a frame shape are connected by corner caps 75. A floor reinforcing member 76 is arranged between adjacent sleepers 73 that are spaced apart. The fascia board 74 and the corner caps 75 may be formed of the resin composition molded body 10 described above.

[0050] The resin composition molded body 10 of this embodiment may be pellets. The shape of the pellets may be, for example, spherical, cylindrical, or irregular. The size of the pellets may be, for example, within the range of 3 mm to 5 mm. The pellets can be used as a raw material for manufacturing the resin composition molded body 10. For example, they can be used as a raw material for manufacturing the paving materials 20, 40, 50 and decking material 60 described above.

[0051] The paving materials 20, 40, 50 and decking material 60 of this embodiment, configured as described above, are made of the resin composition molded body 10 described above, and therefore have stable bending strength, bending modulus, water resistance, and heat resistance at a high level. The paving materials 20, 40, 50 and decking material 60 of this embodiment have high bending strength and bending modulus, so they are less likely to deform or break even when a load is applied to a part of them. In addition, the paving materials 20, 40, 50 and decking material 60 of this embodiment have high water resistance, so they are less likely to deteriorate due to rainwater, and they have high heat resistance, so they are less likely to deteriorate even when exposed to strong sunlight in the summer. Therefore, the paving materials 20, 40, 50 and decking material 60 of this embodiment can be used stably for a long period of time even in an outdoor environment. In particular, structures having thin-walled portions, such as the male tongue and groove 22 of the paving material 20, the hollow portion 42 of the paving material 40, the back side recess 52 of the paving material 50, and the hollow portion 62 of the decking material 60, require high bending strength and bending modulus from the viewpoint of suppressing damage to the thin-walled portions. The paving material of this embodiment consists of the resin composition molded body 10 described above, and since its bending strength and bending modulus are stable at a high level, deformation and damage can be suppressed even if it has thin-walled portions.

[0052] Next, a method for manufacturing a resin composition molded article of the present disclosure will be described using recycled resin as an example. A method for manufacturing a resin composition molded article using recycled resin may include, for example, a recycled resin powder production step of crushing plastic waste to obtain recycled resin powder containing low-melting-point resin particles and non-low-melting-point resin particles; a cellulose-based material particle preparation step of preparing cellulose-based material particles; a mixing step of mixing recycled resin powder and cellulose-based material particles to obtain a resin composition mixed powder; and a molding step of molding the resin composition mixed powder to obtain a resin composition molded article.

[0053] The recycled resin powder production process may include, for example, a plastic waste preparation step of preparing plastic waste, a coarse grinding step of coarsely grinding the plastic waste, a magnetic material removal step of removing magnetic materials from the obtained coarse grinding material, a non-magnetic metal removal step of removing non-magnetic metals from the coarse grinding material, a water washing step of washing the coarse grinding material with water, a volume reduction step of reducing the volume of the coarse grinding material, and a fine grinding step of finely grinding the coarse grinding material.

[0054] The plastic waste prepared in the plastic waste preparation process may include one or more of the following: waste plastics derived from general waste, waste plastic residues, waste plastics derived from industrial waste, and waste plastics derived from marine plastic waste. For example, the plastic waste is waste containing 50% or more by mass of waste plastics. The waste plastic content of the plastic waste may be, for example, in the range of 50% to 100% by mass, 50% to 99.5% by mass, or 50% to 70% by mass.

[0055] When plastic waste is fired at 600°C for 2 hours, the residual amount of the plastic waste after ignition may be within the range of 0.5% by mass or more and 10% by mass or less.

[0056] General waste refers to waste other than industrial waste and marine plastic waste, and includes household waste discarded from ordinary households. Examples of waste plastics derived from general waste include plastics used as containers and packaging materials for products. Waste plastic residue is the residue remaining after separating and recovering a portion of the resin contained in waste plastics derived from general waste, for example, the residue remaining after separating and recovering a portion of low-melting-point resin.

[0057] Industrial waste plastics are plastic waste generated as a result of business activities. Examples of industrial waste plastics include off-specification products and surplus production. Marine plastic waste plastics are plastic waste that accumulates in the ocean when plastic products are directly dumped into the sea, or when plastic products discarded on land are carried into the sea via rivers and lakes. Examples of plastic products include vinyl scraps, PET bottles, and fishing gear. Marine plastic waste plastics also include microplastics, which are plastic products that have deteriorated due to the effects of waves and ultraviolet rays and are smaller than 5 mm.

[0058] There are no particular restrictions on the content of low-melting-point resins and non-low-melting-point resins in synthetic resins contained in plastic waste. The content of low-melting-point resins may be, for example, within the range of 3% to 95% by mass. The content of polystyrene contained in low-melting-point resins may be, for example, within the range of 1% to 100% by mass, or within the range of 5% to 95% by mass. The content of non-low-melting-point resins may be, for example, within the range of 5% to 97% by mass. The ratio of the content of low-melting-point resins to non-low-melting-point resins (low-melting-point resin / non-low-melting-point resin) may be, for example, within the range of 1 / 3 to 5.00 by mass ratio. The content of low-melting-point resins may be 80% by mass or less, or 70% by mass or less. The content of low-melting-point resins may be within any of the following ranges: 5% to 80% by mass, 25% to 80% by mass, 25% to 75% by mass, or 30% to 70% by mass. The content of non-low melting point resin may be 20% by mass or more, or 30% by mass or more. The content of low melting point resin may be within any of the following ranges: 20% by mass or more and 95% by mass or less, 20% by mass or more and 75% by mass or less, 25% by mass or more and 75% by mass or less, or 30% by mass or more and 70% by mass or less. The content ratio of low melting point resin to non-low melting point resin may be less than 4.00 by mass, or within the range of 1 / 3 or more and 3.00 or less.

[0059] When plastic waste is waste plastic residue, the content of low-melting-point resin in the synthetic resin contained in the waste plastic residue may be, for example, 95% by mass or less, or in the range of 25% by mass or more and 95% by mass or less, or in the range of 35% by mass or more and 90% by mass or less. The content of low-melting-point resin in the synthetic resin contained in the waste plastic residue may be 80% by mass or less, or 70% by mass or less. The content of low-melting-point resin may be in any of the following ranges: 5% by mass or more and 80% by mass or less, 25% by mass or more and 80% by mass or less, 25% by mass or more and 75% by mass or less, or 30% by mass or more and 70% by mass or less. The content of polystyrene in the low-melting-point resin may be in the range of 1% by mass or more and 100% by mass or less, or in the range of 5% by mass or more and 95% by mass or less. The content of non-low melting point resin in the above synthetic resin may be, for example, 5% by mass or more, within the range of 5% by mass or more and 75% by mass or within the range of 10% by mass or more and 65% by mass or less. The ratio of the content of low melting point resin to non-low melting point resin in the above synthetic resin (low melting point resin / non-low melting point resin) may be, for example, within the range of 1 / 3 or more and 5.00 by mass ratio, or within the range of 0.71 or more and 3.00 by mass ratio. The content ratio of low melting point resin / non-low melting point resin may be less than 4.00 by mass ratio, or within the range of 1 / 3 or more and 3.00 by mass ratio. The ratio of the content of thermosetting resin to high melting point resin contained in the non-low melting point resin in the above synthetic resin (thermosetting resin / high melting point resin) may be, for example, within the range of 0.01 or more and 100 by mass ratio, or within the range of 0.05 or more and 50 by mass ratio. The content of thermosetting resin in the above synthetic resin may be, for example, 0% by mass or more, or in the range of 1% by mass or more and 10% by mass or less. The content of high melting point resin in the above synthetic resin may be, for example, 5% by mass or more, or in the range of 10% by mass or more and 90% by mass or less.

[0060] There are no particular restrictions on the form of plastic waste; for example, it may be in the form of a bale or a lump. If the manufacturing units (lots) of resin composition molded articles are separated by type of plastic waste, the plastic waste used in each manufacturing unit may be generated at different locations and times. The plastic waste used in each manufacturing unit may have a standard deviation of 2% by mass or more for the low-melting-point resin content, or it may be within the range of 2% by mass or more and 23% by mass or less.

[0061] In the coarse crushing process, a single-shaft shredder can be used as the shredder for coarsely crushing the plastic waste. The size of the coarsely crushed material obtained in the coarse crushing process is not particularly limited, but it may be a size that can pass through a sieve with a mesh size of 20 to 50 mm, for example. The mesh size of the sieve may be 50 mm, 40 mm, or 30 mm.

[0062] In the magnetic material removal process, magnetic separators such as suspended magnetic separators, pulley-type magnetic separators, drum-type magnetic separators, and roll-type magnetic separators can be used to remove magnetic materials from the coarsely ground plastic waste. A single magnetic separator may be used, or two or more types may be used in combination. The magnetic material removal process can remove iron, stainless steel, ferrite, and other materials.

[0063] In the non-magnetic material removal process, an eddy current type separator can be used as a non-magnetic metal separator to remove non-magnetic materials from the coarsely ground plastic waste from which magnetic materials have been removed. Aluminum, copper, zinc, brass, and other materials can be removed through this non-magnetic material removal process.

[0064] In the washing process, a wet-type grinding and washing machine equipped with a grinding function can be used to wash the coarsely ground plastic waste from which non-magnetic substances have been removed. The wet-type grinding and washing machine may also be one that grinds the coarsely ground plastic waste in water to produce coarse plastic particles. For the function of grinding plastic pieces, a grinder equipped with a fixed blade and a rotating blade can be used, which grinds the plastic pieces by sandwiching them between the fixed blade and the rotating blade. The washing process can remove organic matter such as detergents, food stains, and oil stains.

[0065] In the volume reduction process, a compression volume reducer can be used as a volume reduction device for reducing the volume of the coarsely ground material. A compression volume reducer is a device that compresses the coarse plastic particles generated in the washing process to remove moisture adhering to the plastic particles and reduce their volume, thereby obtaining coarse plastic powder. As the compression volume reducer, a screw-type compression volume reducer equipped with a screw inside a barrel with drainage holes can be used. By using a screw-type compression volume reducer, moisture is removed by frictional heat between the screw, barrel, and plastic particles, and a portion of the low-melting-point resin in the plastic particles melts, causing the plastic particles to fuse together and thus reducing the volume of the plastic particles.

[0066] In the fine grinding process, a fine grinder (cutter mill), hammer mill, or pin mill can be used to finely grind the volume-reduced plastic coarse particles.

[0067] As described above, recycled resin powder containing low-melting-point resin particles and non-low-melting-point resin particles can be obtained. The particle size of the recycled resin powder may be adjusted using a classifier. For example, the recycled resin powder may be classified using a sieve. The mesh size of the sieve used for classifying the recycled resin powder may be in the range of, for example, 1 to 3 mm.

[0068] In the process of preparing cellulose-based material particles, the cellulose-based material particles may be, for example, wood powder such as crushed waste materials such as construction waste wood or thinned wood, or sawdust. The particle size of the wood powder may be adjusted using a classifier. For example, the wood powder may be classified using a sieve. The mesh size of the sieve used for classifying the wood powder may be, for example, within the range of 1 to 3 mm.

[0069] In the mixing process, there are no particular restrictions on the method of mixing the recycled resin powder obtained in the resin powder production process with the wood powder prepared from cellulose-based material particles. For example, the mixing may be done using a dry mixing device such as a heater mixer. In addition, inorganic particles or additives may be added as needed.

[0070] Before the mixing process, the composition of the recycled resin powder may be analyzed, and depending on the analysis results, low-melting-point resin particles or non-low-melting-point resin particles may be added. As a method for analyzing the composition of the recycled resin powder, for example, a method can be used in which the low-melting-point resin and the non-low-melting-point resin are separated using the difference in specific gravity, and the content of the separated low-melting-point resin and non-low-melting-point resin is measured. Alternatively, the polystyrene content may be measured by further separating polystyrene from the separated low-melting-point resin using the difference in specific gravity. Furthermore, as a method for analyzing the composition of the resin powder, DSC (differential scanning calorimeter), GC-MS (gas chromatography-mass spectrometer), infrared absorption spectroscopy, and elemental analysis (CHN coder) may be used.

[0071] In the molding process, the resin composition mixed powder can be molded using extrusion, injection, pressing, or casting methods. The form of the resin composition mixed powder during molding is not particularly limited; it may be fed into the molding apparatus as a powder, or it may be granulated by a known method to form pellets (molding material) before being fed into the molding apparatus. The molding temperature varies depending on factors such as the type and amount of low-melting-point resin contained in the resin composition mixed powder, but is typically between 150°C and 190°C.

[0072] The first embodiment of the present disclosure has been described above, but the present disclosure is not limited thereto. For example, in this embodiment, the resin composition molded article 10 contains cellulose-based material particles 13, but it does not have to contain cellulose-based material particles 13. The cellulose-based material particles 13 contained in the resin composition molded article 10 may be replaced with low-melting-point resin or non-low-melting-point resin particles 12. The resin composition molded article of the present disclosure is a molded article of a composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene, and the non-low-melting-point resin particles contain one or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more, the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less, the content of the low-melting-point resin is in the range of 20% by mass or more and 85% by mass or less, and the content of polystyrene in the composition may be 1% by mass or more. Furthermore, the resin composition molded article of the present disclosure is a molded article of a composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene, and the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more, the polystyrene content in the composition is 1% by mass or more, and the content ratio of non-low-melting-point resin particles to low-melting-point resin may be in the range of 0.1 or more and 4.5 or less.

[0073] [Second Embodiment] The resin composition molded article of this embodiment is a molded article of a composition comprising a resin substrate (matrix material) and fillers dispersed in the resin substrate, wherein the fillers are non-low melting point resin particles, cellulosic material particles, and inorganic particles. The resin composition molded article of this embodiment differs from the resin composition molded article of the first embodiment described above in that it includes inorganic particles as an essential component as fillers. The resin substrate is a low melting point resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene. The low melting point resin may be polystyrene alone, or it may be a mixture of polystyrene and a low melting point resin other than polystyrene. Examples of polystyrene and low melting point resins other than polystyrene are the same as those exemplified in the first embodiment. The non-low melting point resin particles include one or both of a high melting point resin having a melting point of 190°C or more and a thermosetting resin. Examples of high melting point resins and thermosetting resins are the same as those exemplified in the first embodiment. Examples of cellulosic material particles are the same as those exemplified in the first embodiment. As inorganic particles, for example, calcium carbonate, talc, kaolin, glass, and carbon can be used. The content of low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less. The content of polystyrene in the composition is 1% by mass or more and may be 80% by mass or less. The content of non-low-melting-point resin particles is in the range of 10% by mass or more and 65% by mass or less in terms of the amount in the composition, or in the range of 0.1 or more and 4.5 in terms of the content ratio of non-low-melting-point resin particles to low-melting-point resin (ratio of non-low-melting-point resin particles to low-melting-point resin content). The content of cellulose-based material particles is in the range of 0.1 or more and 3.0 in terms of the content ratio of cellulose-based material particles to low-melting-point resin (ratio of cellulose-based material particles to low-melting-point resin content). The content of low-melting-point resin, polystyrene, non-low-melting-point resin particles, and cellulose-based material particles may be the same as in the first embodiment. The amount of inorganic particles in the composition may be in the range of 5% by mass or more and less than 50% by mass, 7% by mass or more and 40% by mass or less, or 10% by mass or more and 30% by mass or less. The total amount of cellulose-based material particles and inorganic particles in the composition may be in the range of 10% by mass or more and 75% by mass or less.The resin composition molded article of this embodiment, by containing polystyrene and non-low melting point resin particles, achieves the same effects as the resin composition molded article of the first embodiment. Furthermore, since the resin composition molded article of this embodiment contains inorganic particles, the flexural modulus after water resistance is improved. The resin composition molded article of this embodiment can be used, for example, as civil engineering materials, building materials, and gardening materials. Because the resin composition molded article of this embodiment has excellent water resistance, it is particularly useful as a paving material or building material used outdoors. The resin composition molded article of this embodiment may also be pellets.

[0074] [Third Embodiment] The resin composition molded article of this embodiment is a molded article of a composition comprising a resin substrate (matrix material) and fillers dispersed in the resin substrate, wherein the fillers are non-low melting point resin particles and inorganic particles. The resin composition molded article of this embodiment differs from the resin composition molded articles of the first and second embodiments described above in that it contains inorganic particles as an essential component as fillers and does not contain cellulosic material particles. The resin substrate is a low melting point resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene. The low melting point resin may be polystyrene alone, or it may be a mixture of polystyrene and a low melting point resin other than polystyrene. Examples of polystyrene and low melting point resins other than polystyrene are the same as those exemplified in the first embodiment. The non-low melting point resin particles include one or both of a high melting point resin having a melting point of 190°C or more and a thermosetting resin. Examples of high melting point resins and thermosetting resins are the same as those exemplified in the first embodiment. Examples of inorganic particles are the same as those exemplified in the second embodiment. The content of low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less. The content of polystyrene in the composition is 1% by mass or more, and may be 80% by mass or less. The content of non-low-melting-point resin particles is in the range of 10% by mass or more and 65% by mass or less in terms of the amount of the composition, or in the range of 0.1 or more and 4.5 or less in terms of the content ratio to the low-melting-point resin (non-low-melting-point resin particles / low-melting-point resin content ratio). The content of low-melting-point resin, polystyrene, and non-low-melting-point resin particles may be the same as in the first embodiment. The content of inorganic particles in the composition may be in the range of 5% by mass or more and less than 50% by mass, in the range of 7% by mass or more and 40% by mass or less, or in the range of 10% by mass or more and 30% by mass or less. The resin composition molded article of this embodiment contains polystyrene, inorganic particles and non-low-melting-point resin particles, and since it contains inorganic particles instead of cellulose-based material particles, the bending strength and bending modulus after water resistance are improved. The resin composition molded articles of this embodiment can be used, for example, as civil engineering materials, building materials, gardening materials, transport materials such as transport pallets, and vehicle materials. Furthermore, the resin composition molded articles of this embodiment may also be pellets.

[0075] [Fourth Embodiment] The resin composition molded article of this embodiment is a molded article of a composition comprising a resin substrate (matrix material) and non-low melting point resin particles dispersed in the resin substrate. The resin composition molded article of this embodiment differs from the resin composition molded articles of the first to third embodiments described above in that it does not contain cellulosic material particles and inorganic particles as fillers. The resin substrate is a low melting point resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene. The low melting point resin may be polystyrene alone, or it may be a mixture of polystyrene and a low melting point resin other than polystyrene. Examples of polystyrene and low melting point resins other than polystyrene are the same as those exemplified in the first embodiment. The non-low melting point resin particles include one or both of a high melting point resin having a melting point of 190°C or more and a thermosetting resin. Examples of high melting point resins and thermosetting resins are the same as those exemplified in the first embodiment. The content of the low melting point resin in the composition is in the range of 15% by mass or more and 80% by mass or less. The polystyrene content in the composition is 1% by mass or more, and may be 80% by mass or less. The content of non-low melting point resin particles is within the range of 10% by mass or more and 65% by mass or less in terms of the amount relative to the composition, or within the range of 0.1 or more and 4.5 in terms of the content ratio to the low melting point resin (non-low melting point resin particles / low melting point resin content ratio). The content of low melting point resin, polystyrene, and non-low melting point resin particles may be the same as in the first embodiment. The resin composition molded article of this embodiment has a different texture and appearance from molded articles containing cellulose-based material particles and inorganic particles, as it does not contain these particles. The resin composition molded article of this embodiment can be used, for example, as civil engineering materials, building materials, gardening materials, transport materials such as transport pallets, and vehicle materials. The resin composition molded article of this embodiment may also be pellets.

[0076] 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 powder, non-low-melting-point resin powder, cellulose-based material powder, and inorganic powder were used as raw materials.

[0077] 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).

[0078] 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).

[0079] Low-melting-point resin powder (PS powder): This is made by crushing polystyrene (atactic polystyrene) that has been separated and recovered from waste plastics collected in accordance with the Container and Packaging Recycling Law (glass transition temperature: 100°C).

[0080] 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).

[0081] Cellulose-based material powder (wood powder): This is obtained by crushing construction waste wood separated from construction waste and classifying it using a sieve with a mesh size of 1 mm.

[0082] Inorganic powder (calcium carbonate powder): Calcium bicarbonate powder with an average particle size of 2.0 μm, classified using a sieve with a mesh size of 1 mm.

[0083] [Example 1] PE powder was weighed out in a ratio of 5% by mass, PP powder in a ratio of 5% by mass, PS powder in a ratio of 5% by mass, PET powder in a ratio of 50% by mass, and wood powder in a ratio of 35% by mass. These were then mixed to obtain a raw material powder mixture. To 100 parts by mass of the obtained raw material powder mixture, 0.6 parts by mass of a compatibilizer was added and further mixed. The obtained mixture was put into an extrusion molding machine, and a flat resin composition molded article with a length of 200 mm, a width of 25 mm, and a thickness of 10 mm was produced under the conditions of kneading and molding at a temperature of 165°C.

[0084] [Examples 2-8, Comparative Examples 1-6] Flat resin composition molded articles were produced in the same manner as in Example 1, except that the amounts of PE powder, PP powder, PS powder, PET powder, and wood powder were as shown in Table 1A below.

[0085] Table 1A shows the ratio of polystyrene (PS) content to polyolefin (PE + PP) (PS / (PE + PP)), the ratio of PET powder content to low-melting-point resin (PET powder / low-melting-point resin), the ratio of wood powder content to low-melting-point resin (wood powder / low-melting-point resin), the ratio of PET powder content to polystyrene (PET powder / PS), and the ratio of wood powder content to polystyrene (wood powder / PS) for the flat resin composition molded articles obtained in Examples 1 to 8 and Comparative Examples 1 to 6.

[0086]

[0087] The flat resin composition molded articles obtained in Examples 1 to 8 and Comparative Examples 1 to 6 were evaluated as follows. The results are shown in Table 1B below.

[0088] (Initial Bending Strength) The initial bending strength was measured in accordance with JIS K 7171:2016 (Plastics - Method for Determining Bending Properties). The distance between supports was set to 160 mm. Samples with an initial bending strength of 20 MPa or more were classified as "A", those with an initial bending strength of 15 MPa or more but less than 20 MPa were classified as "B", and those with an initial bending strength of less than 15 MPa were classified as "C".

[0089] (Bending strength after water resistance) A flat resin composition molded body was immersed in 60°C hot water for two weeks. After immersion, the bending strength of the flat resin composition molded body removed from the hot water was measured under the same conditions as the initial bending strength described above. The obtained bending strength was defined as the bending strength after water resistance. A bending strength of 15 MPa or more after water resistance was designated as "A", a bending strength of 10 MPa or more but less than 15 MPa was designated as "B", and a bending strength of less than 10 MPa was designated as "C".

[0090] (Initial Flexural Modulus) The initial flexural modulus was measured in accordance with JIS K 7171:2016 (Plastics - Method for determining bending properties). The distance between supports was set to 160 mm. Samples with an initial flexural modulus of 3500 MPa or higher were classified as "A", those with an initial flexural modulus of 3000 MPa or higher but less than 3500 MPa were classified as "B", and those with an initial flexural modulus of less than 3000 MPa were classified as "C".

[0091] (Flexural modulus after water resistance) A flat resin composition molded body was immersed in 60°C hot water for two weeks. After immersion, the flexural modulus of the flat resin composition molded body removed from the hot water was measured under the same conditions as the initial flexural modulus described above. The obtained bending strength was defined as the flexural modulus after water resistance. A flexural modulus after water resistance of 2000 MPa or more was designated as "A", a flexural modulus of 1500 MPa or more but less than 2000 MPa was designated as "B", and a flexural modulus of less than 1500 MPa was designated as "C".

[0092] (Heat Resistance Temperature) Heat resistance was determined by visually observing a flat resin composition molded body after the following heat cycle test (Test I or Test II), and checking for the presence or absence of cracks with a width of 0.2 mm and a length of 1 mm or more. Products in which no cracks occurred after Test I were classified as "A", products in which cracks occurred after Test I but not after Test II were classified as "B", and products in which cracks occurred after Test II were classified as "C".

[0093] Test I: A flat resin composition molded body is held in a 20°C constant temperature bath for 2 hours, then placed in a 100°C constant temperature bath for 2 hours, and then placed back in the 20°C constant temperature bath. This process is repeated 300 times.

[0094] Test II: A flat resin composition molded body is held in a 20°C constant temperature bath for 2 hours, then placed in a 70°C constant temperature bath for 2 hours, and then placed back in the 20°C constant temperature bath. This process is repeated 300 times.

[0095] (Ratio of non-low melting point resin) The content of non-low melting point resin (PET) in the entire flat resin composition molded article (low non-melting point resin ratio) was calculated, and the obtained low non-melting point resin ratio was evaluated according to the following criteria. A low non-melting point resin ratio of 10% by mass or more was designated as "A", a low non-melting point resin ratio greater than 0% by mass but less than 10% by mass was designated as "B", and a low non-melting point resin ratio of 0% by mass was designated as "C". Non-low melting point resins are difficult to process by heating and therefore difficult to recycle. For this reason, resin composition molded articles with a high non-low melting point resin ratio are useful from the viewpoint of improving the utilization rate of recycled resins.

[0096]

[0097] From the results in Table 1B, it can be seen that the plate-shaped resin composition molded articles of Examples 1 to 8, which contain 5% by mass of polystyrene and whose PET powder and wood powder content are within the range of this disclosure, are excellent in all aspects: initial flexural strength and flexural modulus, flexural strength and flexural modulus after water resistance, and heat resistance temperature. In contrast, the plate-shaped resin composition molded article of Comparative Example 1, which does not contain polystyrene and whose wood powder / low-melting point resin content ratio is greater than the range of this disclosure, has low initial flexural strength and flexural modulus, as well as low flexural strength and flexural modulus after water resistance. The plate-shaped resin composition molded articles of Comparative Examples 1 and 2, which have a low-melting point resin content less than the range of this disclosure, have low heat resistance temperatures. The plate-shaped resin composition molded articles of Comparative Examples 2 to 4, which have a wood powder / low-melting point resin content ratio greater than the range of this disclosure, have high initial flexural strength and flexural modulus, but low flexural strength and flexural modulus after water resistance. Comparative Example 5, a flat resin composition molded article in which the PET powder content and the PET powder / low-melting-point resin content ratio are greater than those within the scope of this disclosure, shows a low initial flexural modulus. Comparative Example 6, which does not contain PET powder, has a non-low-melting-point resin ratio of 0% by mass, and is therefore of low usefulness from the viewpoint of improving the utilization rate of recycled resin.

[0098] [Examples 9-19, Comparative Examples 7-8] Flat resin composition molded articles were produced in the same manner as in Example 1, except that the amounts of PE powder, PP powder, PS powder, PET powder, wood powder, and calcium carbonate powder were as shown in Table 2A below. Table 2A shows the PS / (PE+PP), PET powder / low melting point resin, wood powder / low melting point resin, PET powder / PS, and wood powder / PS of the flat resin composition molded articles obtained in Examples 9-19 and Comparative Examples 7-8.

[0099]

[0100] The flat resin composition molded articles obtained in Examples 9 to 19 and Comparative Examples 7 to 8 were evaluated for initial flexural strength, flexural strength after water resistance, initial flexural modulus, flexural modulus after water resistance, heat resistance temperature, and non-low melting point resin ratio in the same manner as described above. The results are shown in Table 2B below.

[0101]

[0102] From the results in Table 2B, it can be seen that the plate-shaped resin composition molded articles of Examples 9 to 19, which contain 5% by mass of polystyrene and whose PET powder and wood powder content are within the range of this disclosure, are superior to the plate-shaped resin composition molded article of Comparative Example 7, which does not contain polystyrene, in terms of initial flexural strength and flexural modulus, flexural strength and flexural modulus after water resistance, and heat resistance temperature. In particular, it can be seen that the flexural modulus after water resistance is improved in Examples 11 to 14 and 16 to 19, in which a portion of the wood powder is replaced with calcium carbonate powder. Comparative Example 8, which does not contain PET powder, has a non-low melting point resin ratio of 0% by mass, and is therefore of low usefulness from the viewpoint of improving the utilization rate of recycled resin.

[0103] [Examples 20-37] Flat resin composition molded articles were produced in the same manner as in Example 1, except that the amounts of PE powder, PP powder, PS powder, PET powder, and wood powder were as shown in Table 3A below. The PS / (PE+PP), PET powder / low melting point resin, wood powder / low melting point resin, PET powder / PS, and wood powder / PS of the flat resin composition molded articles obtained in Examples 11-28 are shown in Table 3A.

[0104]

[0105] The flat resin composition molded articles obtained in Examples 20 to 37 were evaluated for initial bending strength, bending strength after water resistance, initial bending modulus, bending modulus after water resistance, and heat resistance temperature in the same manner as described above. The results are shown in Table 3B below.

[0106]

[0107] From the results in Table 3B, it can be seen that the plate-shaped resin composition molded articles of Examples 20 to 37, in which the polystyrene, PET powder content and wood powder content are within the scope of this disclosure, are excellent in all aspects, including initial flexural strength and flexural modulus, flexural strength and flexural modulus after water resistance, heat resistance temperature, and non-melting point resin ratio.

[0108] The nature of this disclosure is described below.

[0109] (Note 1) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

[0110] (Note 2) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

[0111] (Note 3) A resin composition molded article according to Note 1 or 2, wherein the polystyrene content in the composition is 5% by mass or more.

[0112] (Note 4) A resin composition molded article according to any one of Notes 1 to 3, wherein the polystyrene content in the composition is 80% by mass or less.

[0113] (Note 5) The resin composition molded article according to any one of Notes 1 to 4, wherein the low-melting-point resin contains a resin other than polystyrene, and the content ratio of polystyrene to the resin other than polystyrene is in the range of 0.1 to 10.

[0114] (Note 6) The resin composition molded article according to any one of Notes 1 to 5, wherein the cellulose-based material particles include at least wood powder particles.

[0115] (Note 7) The resin composition molded article according to any one of Notes 1 to 6, 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 3 mm.

[0116] (Note 8) Furthermore, a molded resin composition according to any one of Notes 1 to 7, which also contains inorganic particles.

[0117] (Note 9) The total content of the cellulose-based material particles and the inorganic particles in the composition is within the range of 10% by mass or more and 75% by mass or less. The resin composition molded article as described in Note 8.

[0118] (Note 10) A resin composition molded article according to any one of Notes 1 to 9, further comprising a compatibilizer in an amount of 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the composition.

[0119] (Note 11) A paving material comprising a molded resin composition described in any one of Notes 1 to 10.

[0120] (Note 12) A decking material comprising a molded resin composition described in any one of Notes 1 to 10.

[0121] (Note 13) A pellet of a composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

[0122] (Note 14) A pellet of a composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

[0123] (Note 15) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C and contains at least polystyrene, and the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more, the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less, and the content of the polystyrene in the composition is 1% by mass or more.

[0124] (Note 16) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene, and the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more, the polystyrene content in the composition is 1% by mass or more, and the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less.

[0125] (Note 17) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, cellulose-based material particles dispersed in the resin substrate, and inorganic particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less; and the content of the inorganic particles in the composition is in the range of 5% by mass or more and less than 50% by mass or less.

[0126] (Note 18) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, cellulose-based material particles dispersed in the resin substrate, and inorganic particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less; and the content of the inorganic particles in the composition is in the range of 5% by mass or more and less than 50% by mass.

[0127] (Note 19) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and inorganic particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content of the inorganic particles in the composition is in the range of 5% by mass or more and less than 50% by mass.

[0128] (Note 20) A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and inorganic particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; and the content of the inorganic particles in the composition is in the range of 5% by mass or more and less than 50% by mass.

[0129] 10...Resin composition molded body, 11...Resin base material, 12...Non-low melting point resin particles, 13...Cellulose-based material 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, 40...Paving material, 41...Main body, 42...Hollow part, 42a...Internal space, 43...Backside recess, 44...Small groove, 50...Paving material, 51...Main body, 52...Backside recess, 52a...Internal space, 60...Deck material, 61...Surface, 62...Hollow part, 70...Deck structure, 71...Foundation stone, 72...Support post, 73...Main beam, 74...Fastener board, 75...Corner cap, 76...Floor board reinforcement material

Claims

1. A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both a high-melting-point resin and a thermosetting resin, with a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

2. A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both a high-melting-point resin and a thermosetting resin, the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

3. A resin composition molded article according to claim 1 or 2, wherein the polystyrene content in the composition is 5% by mass or more.

4. A resin composition molded article according to any one of claims 1 to 3, wherein the polystyrene content in the composition is 80% by mass or less.

5. The resin composition molded article according to any one of claims 1 to 4 or 2, wherein the low-melting-point resin includes a resin other than polystyrene, and the content ratio of polystyrene to the resin other than polystyrene is in the range of 0.1 to 10.

6. The resin composition molded article according to any one of claims 1 to 5, wherein the cellulose-based material particles include at least wood powder particles.

7. The resin composition molded article according to any one of claims 1 to 6, 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 3 mm.

8. A resin composition molded article according to any one of claims 1 to 7, further comprising inorganic particles.

9. The total content of the cellulose-based material particles and the inorganic particles in the composition is within the range of 10% by mass or more and 75% by mass or less. The resin composition molded article according to claim 8.

10. A resin composition molded article according to any one of claims 1 to 9, further comprising a compatibilizer in an amount of 0.6 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the composition.

11. The resin composition molded article according to any one of claims 1 to 10, wherein the resin composition molded article is a paving material or a decking material.

12. A pellet of a composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both a high-melting-point resin and a thermosetting resin, with a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content of the non-low-melting-point resin particles in the composition is in the range of 10% by mass or more and 65% by mass or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

13. A pellet of a composition comprising a resin substrate containing a low-melting-point resin, non-low-melting-point resin particles dispersed in the resin substrate, and cellulose-based material particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain either or both a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; the content of the polystyrene in the composition is 1% by mass or more; the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less; and the content ratio of the cellulose-based material particles to the low-melting-point resin is in the range of 0.1 or more and 3.0 or less.

14. A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain one or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the content of the low-melting-point resin in the composition is in the range of 15% by mass or more and 80% by mass or less; and the content of the polystyrene in the composition is 1% by mass or more.

15. A molded article of a resin composition comprising a resin substrate containing a low-melting-point resin and non-low-melting-point resin particles dispersed in the resin substrate, wherein the low-melting-point resin is a resin having a melting point in the range of 80°C or more and less than 190°C, and contains at least polystyrene; the non-low-melting-point resin particles contain one or both of a high-melting-point resin and a thermosetting resin having a melting point of 190°C or more; the polystyrene content in the composition is 1% by mass or more; and the content ratio of the non-low-melting-point resin particles to the low-melting-point resin is in the range of 0.1 or more and 4.5 or less.

Images