Extruded profiles and building materials

Abstract

This invention suppresses discoloration of the surface of extruded profiles containing chemically treated cellulose-based powder and resin, while enabling an increase in the amount of cellulose-based powder contained in the extruded profiles. [Solution] The extruded profile 20 comprises a base portion 21 containing chemically treated cellulose powder and resin, and a surface portion 22 covering the base portion 21 and containing chemically treated cellulose powder and resin. The content of cellulose powder in the surface portion 22 is lower than the content of cellulose powder in the base portion 21.

Description

Technical Field

[0001] The present invention relates to an extruded molded product containing a chemically treated cellulosic powder and a resin, and a building material made of the extruded molded product.

Background Art

[0002] In consideration of the environment, cellulosic powders may be incorporated into extruded molded products. Cellulosic powders are produced, for example, from raw materials derived from plants, mixed with resins, and contained in extruded molded products. Such extruded molded products are used as various building materials and are required to have durability so as to withstand long-term use. Therefore, a chemical treatment for modifying durability may be preliminarily applied to the cellulosic powder before mixing with the resin. Further, with regard to cellulosic powders, conventionally, thermoplastic modified wood, which is acetylated wood powder or the like, is known (see Patent Document 1).

[0003] The conventional thermoplastic modified wood described in Patent Document 1 is mixed with a thermoplastic resin and used for molding molded products. By introducing at least one organic group into a part of the hydroxyl groups of the thermoplastic modified wood, the affinity of the thermoplastic modified wood for the thermoplastic resin is improved, and the thermoplastic modified wood is uniformly dispersed in the thermoplastic resin. However, in molded products containing conventional thermoplastic modified wood, when the content of the thermoplastic modified wood is increased, there is a risk that the discoloration of the surface of the molded product becomes conspicuous along with the discoloration of the thermoplastic modified wood by sunlight (particularly, ultraviolet rays). Therefore, from the viewpoint of environmental consideration, it is difficult to respond to the demand for increasing the content of the thermoplastic modified wood.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above-mentioned conventional problems, and its objective is to suppress discoloration of the surface of an extruded profile containing chemically treated cellulose-based powder and resin, while enabling an increase in the amount of cellulose-based powder contained in the extruded profile. [Means for solving the problem]

[0006] The present invention comprises a base containing chemically treated cellulose-based powder and resin, and a surface layer containing chemically treated cellulose-based powder and resin covering the base. The extruded profile has a lower content of cellulose-based powder in the surface layer than in the base layer. Furthermore, the present invention relates to a building material made from the extruded profile of the present invention. [Effects of the Invention]

[0007] According to the present invention, it is possible to increase the amount of cellulose-based powder contained in an extruded profile while suppressing discoloration of the surface of the extruded profile containing chemically treated cellulose-based powder and resin. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing a deck using the building materials of this embodiment. [Figure 2] This is a diagram showing the extruded profile of this embodiment. [Figure 3] This flowchart shows the manufacturing procedure (process) for the extruded profiles and building materials of this embodiment. [Figure 4] This diagram schematically shows the state of each stage in the manufacturing process of the extruded profile according to this embodiment. [Figure 5] This figure shows another example of the extruded profile of this embodiment. [Modes for carrying out the invention]

[0009] One embodiment of the extruded profiles and building materials of the present invention will be described with reference to the drawings. The extruded profiles of this embodiment are profiles formed by extrusion molding, and are formed by an extruder to have a constant cross-sectional shape along their entire length. The building materials of this embodiment consist of the extruded profiles of this embodiment and are used as building materials. The building materials are made of extruded profiles, and the extruded profiles and building materials are used, for example, in outdoor structures where durability is required.

[0010] Figure 1 is a perspective view showing a deck 2 using the building material 1 of this embodiment, and shows a part of the deck 2 viewed from diagonally above. As shown in the figure, deck 2 is an outdoor structure attached to a building (not shown) and installed outdoors. Deck 2 also comprises multiple support beams 3, multiple girders (not shown) stretched between the support beams 3, multiple joists (not shown) stretched between the girders, multiple flooring materials 10 laid on top of the joists, and skirting boards 4 provided around the perimeter of the multiple flooring materials 10.

[0011] Multiple flooring materials 10 are board-shaped decking materials (boards) and are installed on the floor surface of deck 2. Multiple flooring materials 10 are arranged in parallel to each other with their edges touching, forming the floor surface of deck 2. Flooring materials 10 are building materials 1 used in deck 2, and are installed in a part of deck 2, forming a part of deck 2. Multiple flooring materials 10 and building materials 1 are each made of extruded profiles 20, and are manufactured by processing extruded profiles 20 with the same cross-sectional shape. Flooring materials 10, building materials 1, and extruded profiles 20 are installed outdoors of the building and are exposed to the outdoor environment.

[0012] Figure 2 shows the extruded profile 20 of this embodiment, and Figure 2A is a perspective view showing a part of the longitudinal direction of the extruded profile 20. Figure 2B is a cross-section of the extruded profile 20 cut along the line X1-X1 in Figure 2A, showing a cross-section perpendicular to the longitudinal direction of the extruded profile 20. As shown in the figure, the extruded profile 20 comprises a base portion 21 and a surface portion 22 that are integrally extruded. The base portion 21 is the central part located on the side of the extruded profile 20 and constitutes the main part of the extruded profile 20. The surface portion 22 is the outer surface portion located on the outer surface of the extruded profile 20 and is formed on top of the outer surface of the base portion 21, constituting the outer surface of the extruded profile 20.

[0013] The extruded profile 20 contains at least chemically treated cellulose powder and resin. The extruded profile 20 consists of two integral parts (base portion 21 and surface portion 22) and is formed in a solid structure (solid shape). The surface portion 22 is a covering portion that covers the outer surface of the base portion 21 and covers the base portion 21. The base portion 21 is an inner portion located on the inner side of the extruded profile 20 relative to the surface portion 22 and is covered by the base portion 21 except for the portion located at the end face in the longitudinal direction of the extruded profile 20. The base portion 21 and the surface portion 22 are joined together to constitute the extruded profile 20.

[0014] The base portion 21 of the extruded profile 20 contains at least chemically treated cellulose-based powder and resin, and the surface portion 22 of the extruded profile 20 contains at least chemically treated cellulose-based powder and resin. Cellulose-based powder is a powder (powder) that mainly contains cellulose, and in addition to cellulose, it contains other components. Cellulose-based powder is produced from raw materials obtained from plants containing cellulose and is formed into a powder form. Cellulose-based powder consists of at least one powder from among wood powder, bamboo powder, pulp, wood fiber powder, rice husks, and recycled paper powder.

[0015] Chemical treatment is a modification process that chemically alters (improves) cellulosic powder, using chemical agents to modify the powder. These chemical agents are liquid or gaseous substances (modifiers) that modify the cellulosic powder. In this context, chemical treatment refers to a modification process (durability treatment) that alters the durability of the cellulosic powder. A chemically treated cellulosic powder is one whose durability has been improved by the chemical treatment, resulting in higher durability than an untreated cellulosic powder. The durability of cellulosic powder includes, for example, resistance to decay, weathering, termite resistance, strength, and water resistance. Furthermore, chemically treated cellulosic powder exhibits reduced moisture absorption.

[0016] Chemical treatments for cellulose-based powders include, for example, acetylation, formalization, phenol resin treatment, acrylic resin treatment, and furan resin treatment. Therefore, chemically treated cellulose-based powders include, for example, acetylated cellulose-based powders (acetylated cellulose-based powders) that have been acetylated, formalized cellulose-based powders (formalized cellulose-based powders) that have been formalized, phenol resin-treated cellulose-based powders that have been impregnated with phenol resin, acrylic resin-treated cellulose-based powders that have been impregnated with acrylic resin, and furan resin-treated cellulose-based powders that have been impregnated with furan resin.

[0017] The resin contained in the base portion 21 and the surface layer portion 22 of the extruded profile 20 is a synthetic resin and is mixed with chemically treated cellulose-based powder. Further, the base portion 21 and the surface layer portion 22 contain a compatibilizer that enhances the affinity between the chemically treated cellulose-based powder and the resin. The compatibilizer is an additive that aids in the mixing of the chemically treated cellulose-based powder and the resin and has a high affinity for each of the chemically treated cellulose-based powder and the resin. The compatibilizer increases the compatibility between the chemically treated cellulose-based powder and the resin, and the chemically treated cellulose-based powder and the resin are uniformly mixed. Here, the resin is a thermoplastic resin, such as polypropylene, polyethylene, or polyvinyl chloride. Further, the compatibilizer is an unsaturated carboxylic acid-modified polyolefin.

[0018] The base portion 21 and the surface layer portion 22 of the extruded profile 20 are made of raw materials containing a chemically treated cellulose-based powder and a resin. The raw materials are in a mixed state with each other and constitute each of the base portion 21 and the surface layer portion 22, and the cellulose-based powder is dispersed inside each of the base portion 21 and the surface layer portion 22. Further, the base portion 21 and the surface layer portion 22 contain other additives in addition to the compatibilizer. The other additives are, for example, at least one additive selected from the group consisting of a colorant, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, and a filler, and the base portion 21 and the surface layer portion 22 each contain at least one additive among a plurality of other additives.

[0019] In the base portion 21 and the surface layer portion 22 of the extruded profile 20, the content rates of the chemically treated cellulose-based powder and the resin are different from each other. The content rate of the cellulose-based powder in the surface layer portion 22 is lower (smaller) than the content rate of the cellulose-based powder in the base portion 21, and the content rate of the resin in the surface layer portion 22 is higher (larger) than the content rate of the resin in the base portion 21. Therefore, the content rate of the cellulose-based powder in the base portion 21 is higher (larger) than the content rate of the cellulose-based powder in the surface layer portion 22, and the content rate of the resin in the base portion 21 is lower (smaller) than the content rate of the resin in the surface layer portion 22.

[0020] The content ratio is in mass percentage (mass% (wt%)), and is calculated for each of the base part 21 and the surface layer part 22 based on the total mass of each of them. Also, for each of the base part 21 and the surface layer part 22, the content ratio of each component contained therein (cellulose-based powder subjected to chemical treatment, resin, compatibilizer, etc.) is represented in mass%. The content ratio of the cellulose-based powder in the base part 21 is the percentage (mass%) of the mass of the cellulose-based powder with respect to the total mass of the base part 21, and the content ratio of the resin in the base part 21 is the percentage (mass%) of the mass of the resin with respect to the total mass of the base part 21. The content ratio of the cellulose-based powder in the surface layer part 22 is the percentage (mass%) of the mass of the cellulose-based powder with respect to the total mass of the surface layer part 22, and the content ratio of the resin in the surface layer part 22 is the percentage (mass%) of the mass of the resin with respect to the total mass of the surface layer part 22.

[0021] The content ratio of the cellulose-based powder in the base part 21 of the extruded profile 20 is 45 to 90 mass% (45 mass% or more and 90 mass% or less). The cellulose-based powder is blended into the base part 21 so that the content ratio is within the range of 45 to 90 mass%, and the content ratio of the cellulose-based powder in the base part 21 is adjusted to be within the range of 45 to 90 mass%. Also, the content ratio of the cellulose-based powder in the surface layer part 22 of the extruded profile 20 is 1 to 40 mass% (1 mass% or more and 40 mass% or less). The cellulose-based powder is blended into the surface layer part 22 so that the content ratio is within the range of 1 to 40 mass%, and the content ratio of the cellulose-based powder in the surface layer part 22 is adjusted to be within the range of 1 to 40 mass%.

[0022] For each of the base part 21 and the surface layer part 22 of the extruded profile 20, the compatibilizer is 0.5 to 5 wt% (0.5 wt% or more and 5 wt% or less). The compatibilizer is blended into each of the base part 21 and the surface layer part 22 so that the content ratio is within the range of 0.5 to 5 wt%, and the content ratio of the compatibilizer in each of the base part 21 and the surface layer part 22 is adjusted to be within the range of 0.5 to 5 wt%. Also, among the components excluding the cellulose-based powder and the compatibilizer for each of the base part 21 and the surface layer part 22, the content ratio of the resin is the highest, and additives other than the compatibilizer are further added.

[0023] The thickness of the surface layer 22 of the extruded profile 20 is 0.5 to 5 mm (0.5 mm or more and 5 mm or less). The surface layer 22 is formed to a thickness within the range of 0.5 to 5 mm throughout and is exposed to the outside of the extruded profile 20. The base portion 21 is shielded by the surface layer 22 and is not exposed to the outside of the extruded profile 20, except for the portion located at the end face in the longitudinal direction of the extruded profile 20.

[0024] Figure 3 is a flowchart showing the manufacturing procedure (process) for the extruded profile 20 and building material 1 of this embodiment. Figure 4 is a schematic diagram showing the state at each stage of the manufacturing process of the extruded profile 20 of this embodiment. As shown in the figure, before the manufacture of the extruded profile 20 (before extrusion molding), the raw materials are chemically treated (S101 in Figure 3) to produce chemically treated cellulose powder (S102 in Figure 3). The raw materials are the base materials for the chemically treated cellulose powder, and are either untreated cellulose powder or non-powdered material 30 (see Figure 4A) that forms the base material for untreated cellulose powder.

[0025] When non-powdered material 30 is the raw material, the non-powdered material 30 is chemically treated to obtain chemically treated non-powdered material 31 (chemically treated non-powdered material) (see Figure 4B). Subsequently, the non-powdered material 31 is formed into a powder to produce chemically treated cellulose-based powder 32 (chemically treated cellulose-based powder) (see Figure 4C). Here, the non-powdered material 30 is wood, and the cellulose-based powder 32 is chemically treated wood powder (chemically treated wood powder).

[0026] Wood powder is produced by crushing non-powdered material 31 (chemically treated wood) or scraps of non-powdered material 31, which are wood that has been chemically treated. Alternatively, wood powder such as sawdust or shavings is produced by processing (including cutting) the non-powdered material 31. In contrast, if the raw material is a cellulose-based powder that has not been chemically treated, the cellulose-based powder used as the raw material is chemically treated to produce a chemically treated cellulose-based powder 32.

[0027] Next, the multiple raw materials for the extruded profile 20 are mixed (S103 in Figure 3) to form pellets containing the multiple raw materials (S104 in Figure 3). The multiple raw materials are chemically treated cellulose powder 32, resin, compatibilizer, and other additives. Here, the resin is formed into granular pellets (resin pellets 40) (see Figure 4D), and the compatibilizer is formed into granular pellets (compatibilizer pellets 41) (see Figure 4E). The resin in the resin pellets 40 is virgin resin, recycled resin, or biomass resin.

[0028] Multiple raw materials, including cellulose-based powder 32, resin (resin pellets 40), and a compatibilizer (compatibilizer pellets 41), are fed into an extruder, heated and kneaded inside the extruder, and mixed together. The extruder also cuts the mixture of the multiple raw materials as it is extruded, forming the mixture into granular raw material pellets 42 and 43 (see Figures 4F and 4G). The raw material pellets 42 and 43 are the pellets that become the raw materials for the extruded profile 20 when the extruded profile 20 is formed.

[0029] Two types of raw material pellets 42 and 43 (first raw material pellet 42 and second raw material pellet 43) are molded separately using an extruder. Of the two types of raw material pellets 42 and 43, the first raw material pellet 42 becomes the raw material for the base 21 of the extruded profile 20, and the second raw material pellet 43 becomes the raw material for the surface layer 22 of the extruded profile 20. The two types of raw material pellets 42 and 43 have different content ratios of chemically treated cellulose powder 32 and resin.

[0030] Using an extruder capable of co-extrusion, two types of raw material pellets 42 and 43 are heated and melted, and the base portion 21 and the surface portion 22 are co-extruded and continuously extruded. In this way, the base portion 21 is extruded using the first raw material pellet 42 as raw material, and the surface portion 22 is extruded using the second raw material pellet 43 as raw material. In this way, an extruded profile 20 (see Figure 4H) in which the base portion 21 and the surface portion 22 are integrated is continuously manufactured by extrusion (S105 in Figure 3). The extruded profile 20 is cut in a direction intersecting the longitudinal direction. Subsequently, the extruded profile 20 is processed to manufacture building material 1 from the extruded profile 20 (S106 in Figure 3).

[0031] In the extruded profile 20 described above, the content of cellulose-based powder 32 in the surface layer 22 is lower than the content of cellulose-based powder 32 in the base layer 21. Therefore, even if the cellulose-based powder 32 in the surface layer 22 of the extruded profile 20 discolors due to sunlight (especially ultraviolet rays), the degree of discoloration of the surface layer 22 is reduced, making the discoloration of the surface layer 22 less noticeable. Furthermore, the content of cellulose-based powder 32 in the base layer 21 is higher than the content of cellulose-based powder 32 in the surface layer 22, allowing for an increase in the content (amount added) of cellulose-based powder 32 in the base layer 21 of the extruded profile 20. Consequently, in the extruded profile 20 and building material 1, it is possible to increase the amount of cellulose-based powder 32 contained in the extruded profile 20 while suppressing discoloration of the surface of the extruded profile 20.

[0032] In the surface layer 22 of the extruded profile 20, if the content of cellulose-based powder 32 is less than 1% by mass, it becomes difficult to achieve a wood-like texture due to the cellulose-based powder 32. Also, if the content of cellulose-based powder 32 is greater than 40% by mass, discoloration of the surface layer 22 due to discoloration of the cellulose-based powder 32 becomes more noticeable. In contrast, when the content of cellulose-based powder 32 is between 1% and 40% by mass, it is possible to ensure a wood-like texture of the surface layer 22 while suppressing the noticeable discoloration of the surface layer 22. It is more preferable that the content of cellulose-based powder 32 is between 15% and 35% by mass (15% to 35% by mass). In this case, it is possible to enhance the wood-like texture of the surface layer 22 while making the discoloration of the surface layer 22 less noticeable.

[0033] If the content of cellulose-based powder 32 in the base 21 of the extruded profile 20 is less than 45% by mass, there is a risk that the amount of cellulose-based powder 32 contained in the base 21 will be insufficient. Furthermore, if the content of cellulose-based powder 32 is greater than 90% by mass, there is a risk that the base 21 of the extruded profile 20 will be difficult to extrude due to the influence of the cellulose-based powder 32. In contrast, if the content of cellulose-based powder 32 is between 40% and 90% by mass, the amount of cellulose-based powder 32 contained in the base 21 can be ensured, and the base 21 can be smoothly extruded. A more preferable content of cellulose-based powder 32 is between 45% and 65% by mass (45% to 65% by mass). In this case, the base 21 can be easily extruded while ensuring the content of cellulose-based powder 32 contained in the base 21.

[0034] If the thickness of the surface layer 22 of the extruded profile 20 is less than 0.5 mm, there is a risk that the impact strength of the surface layer 22 may be affected. If the surface layer 22 is damaged, there is a concern that the base 21 may be exposed. Also, if the thickness of the surface layer 22 is greater than 5 mm, there is a risk that the cost of the extruded profile 20 will increase due to the increased amount of resin contained in the surface layer 22. In contrast, if the thickness of the surface layer 22 is between 0.5 and 5 mm, the impact strength of the surface layer 22 can be ensured, while suppressing an increase in the amount of resin contained in the surface layer 22 and an increase in the cost of the extruded profile 20. It is more preferable that the thickness of the surface layer 22 be between 1 and 2 mm (1 mm or more and 2 mm or less). In this case, it is possible to ensure the impact strength of the surface layer 22 while reliably suppressing an increase in the amount of resin contained in the surface layer 22 and an increase in the cost of the extruded profile 20.

[0035] Furthermore, regarding the resin and compatibilizer contained in the base 21 and surface layer 22 of the extruded profile 20, polypropylene and unsaturated carboxylic acid-modified polyolefin have high compatibility and are compatible. Therefore, when the resin is polypropylene and the compatibilizer is unsaturated carboxylic acid-modified polyolefin, the impact strength of the base 21, surface layer 22, and extruded profile 20 is improved. In addition, when a coloring agent is added to the surface layer 22 for design or decoration, sunlight including ultraviolet rays is reflected by the surface layer 22, preventing sunlight from reaching the base 21. As a result, discoloration of the cellulose-based powder 32 contained in the base 21 due to sunlight is suppressed.

[0036] The chemically treated cellulose powder 32 has low moisture absorption. Therefore, even when the extruded profile 20 is used in a place where it is wet (for example, in the ground, underwater, in puddles or other places that come into direct contact with water, or in places that are hot and humid), the absorption of water into the extruded profile 20 is suppressed, and changes in the dimensions of the extruded profile 20 are suppressed. Furthermore, the extruded profile 20 is not limited to being a building material 1 for deck 2, but can be used as a building material 1 for various structures (for example, exterior elements such as fences and louvers, and buildings). The extruded profile 20 is not limited to a solid structure (solid shape), but can be formed into various structures (shapes).

[0037] Figure 5 shows another example of the extruded profile 20 of this embodiment, where Figure 5A is a perspective view showing a portion of the extruded profile 20 in the longitudinal direction. Figure 5B is a cross-section of the extruded profile 20 cut along the line X2-X2 in Figure 5A, showing a cross-section perpendicular to the longitudinal direction of the extruded profile 20. As shown in the figure, the extruded profile 20 is formed in a hollow structure (hollow shape) and includes at least one hollow section 23. The hollow section 23 is formed hollow inside the extruded profile 20 and extends in the longitudinal direction of the extruded profile 20. Here, multiple hollow sections 23 are formed inside the base 21 of the extruded profile 20. The multiple hollow sections 23 are formed in parallel and spaced apart from each other.

[0038] As described above, this embodiment discloses the extruded profiles described in (1) to (3) below, and the building materials described in (4).

[0039] (1) comprising a base containing chemically treated cellulose powder and resin, and a surface layer containing chemically treated cellulose powder and resin covering the base, An extruded profile in which the content of the cellulose-based powder in the surface layer is lower than the content of the cellulose-based powder in the base. In the extruded profiles described in (1), it is possible to increase the amount of cellulose-based powder contained in the extruded profiles while suppressing discoloration of the surface of the extruded profiles containing chemically treated cellulose-based powder and resin.

[0040] (2) In the extruded profiles described in (1), The content of the cellulose-based powder in the surface layer is 1 to 40% by mass. An extruded profile having a cellulosic powder content of 45 to 90% by mass in the base portion. (2) The extruded profiles described can ensure a wood-like texture on the surface and suppress noticeable discoloration of the surface. In addition, the amount of cellulose-based powder contained in the base can be ensured and the base can be smoothly extruded.

[0041] (3) In the extruded profiles described in (1) or (2), The extruded profile has a surface layer thickness of 0.5 to 5 mm. (3) The extruded profiles described above ensure impact strength of the surface layer while suppressing an increase in the amount of resin contained in the surface layer and an increase in the cost of the extruded profiles.

[0042] (4) Building materials consisting of extruded profiles as described in any of (1) to (3). In the building materials described in (4), in building materials made of extruded profiles, it is possible to increase the amount of cellulose-based powder contained in the extruded profiles while suppressing discoloration of the surface of the extruded profiles containing chemically treated cellulose-based powder and resin. [Explanation of Symbols]

[0043] 1... Building materials, 2... Decks, 3... Beams, 4... Skirting boards, 10... Flooring, 20... Extruded profiles, 21... Base, 22... Surface layer, 23... Hollow section, 30... Non-powdered materials, 31... Non-powdered materials, 32... Cellulose-based powders, 40... Resin pellets, 41... Compatibilizer pellets, 42... Primary raw material pellets, 43... Secondary raw material pellets.

Claims

1. It comprises a base containing chemically treated cellulose-based powder and resin, and a surface layer containing chemically treated cellulose-based powder and resin that covers the base, An extruded profile in which the content of the cellulose-based powder in the surface layer is lower than the content of the cellulose-based powder in the base.

2. In the extruded profile described in claim 1, The content of the cellulose-based powder in the surface layer is 1 to 40% by mass. An extruded profile wherein the content of the cellulose-based powder in the base portion is 45 to 90% by mass.

3. In the extruded profile described in claim 1 or 2, The extruded profile has a surface layer thickness of 0.5 to 5 mm.

4. A building material comprising an extruded profile as described in claim 1 or 2.

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