Integral extrusion-molded body

Abstract

To provide an integrally extrusion-molded body which is lightweight, has high strength and a high-quality woody feeling, and can be touched with a bare skin even if the surface temperature is high.SOLUTION: An integral extrusion-molded body (10) comprising: a core material (11) having an inner space; and a covering layer (13) covering at least a part of an outer face of the core material, wherein the covering layer contains a wood powder, a foaming agent, and a coloring agent, and has an expansion ratio of 1.5 to 3.5 times and a thickness of 3.0 to 8.0 0mm, and at least a part of the covering layer is sanded.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an integrally extruded product containing a metal core material used as a building component, etc., and in particular to an integrally extruded product suitable for use in environments where the surface temperature is high, such as decking materials and benching materials, where the product will come into contact with bare skin. [Background technology]

[0002] One-piece extrusion molded products in which the outer surface of a metal core material is extruded and coated with a thermoplastic resin containing wood powder are used as various building components. For example, Patent Documents 1 and 2 describe one-piece extrusion molded products in which the outer surface of a metal core material such as aluminum has a coating layer containing a polyolefin resin and wood powder, giving the product a high-quality wood texture.

[0003] Unlike wood, such integrally extruded molded products are free from the problem of corrosion, but when used in applications where the surface temperature is high, such as as a flooring material for a residential terrace, there is a risk of burns when walking on it barefoot. In this regard, Patent Documents 3 and 4 describe flooring materials whose surface is formed from a synthetic resin containing a heat-shielding pigment, which can reflect solar radiation and suppress heat accumulation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-066403 [Patent Document 2] International Publication No. WO2016 / 006707 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-252366 [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-210742 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the flooring materials described in Patent Documents 3 and 4 are designed on the assumption that they will be heated from the surface using sunlight as a heat source, and so are not effective in suppressing heat accumulation when the environmental temperature in which the flooring material is used is high. For example, when used as the floor of a sauna room or a stepped deck for users to sit on, walking barefoot or touching it with bare skin can be painfully hot.

[0006] The present invention has been made in consideration of the above, and aims to provide a wood-like integrally extruded molded body which is made by extruding a metal core material and a thermoplastic resin containing wood powder and which reduces the degree of heat felt when the surface touches bare skin, not only when heated by rays from the sun or the like, but also when the environmental temperature in which it is used is high. [Means for solving the problem]

[0007] The inventors noticed that even if the surface temperature is the same, the heat felt when touched varies depending on the material, and arrived at the present invention by changing the structure of the coating layer.

[0008] The integrally extruded molded body of the present invention has a core material having an internal space and a coating layer that covers at least a portion of the outer surface of the core material, wherein the coating layer contains a resin, wood flour, a foaming agent, and a colorant, has an expansion ratio of 1.5 to 3.5 times, a thickness of 3.0 to 8.0 mm, and has at least a portion of its surface sanded.

[0009] Here, the core material having an internal space includes not only cylindrical ones, but also ones with a cross section that is roughly U-shaped or roughly C-shaped, with a part of the cylindrical shape cut away.

[0010] With this configuration, even if the surface temperature of the coating layer is high, the heat felt when touching bare skin can be reduced.

[0011] Preferably, the foaming agent is heat-expandable microspheres having a structure in which a foaming agent that vaporizes upon heating is encapsulated in a resin shell. The coating layer preferably has an expansion ratio of 2.1 to 3.0. The coating layer preferably has a thickness of 3.1 to 5.0 mm. These features further reduce the heat felt by bare skin when the surface temperature of the coating layer is high.

[0012] Preferably, the core material is made of aluminum or an aluminum alloy. Also, preferably, the integrally extruded body further has an adhesive layer between the core material and the coating layer. [Effects of the Invention]

[0013] The one-piece extrusion molded product of the present invention is lightweight, strong, and has a high-quality wood texture, achieved by extrusion coating the surface of a metal core with a polyolefin resin containing wood powder. Furthermore, the coating layer has an expansion ratio of 1.5 to 3.5 times, a thickness of 3.0 to 8.0 mm, and at least a portion of the surface is sanded, so that the heat felt by bare skin when it touches the surface can be reduced even when the surface temperature is high. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are diagrams showing examples of the structure of an integrally extruded body of the present invention. [Figure 2] FIG. 1 is a diagram illustrating an example of the structure of an integrated extrusion molding machine. DETAILED DESCRIPTION OF THE INVENTION

[0015] In this specification, integral extrusion molding means that the material for the covering layer is extruded and at the same time the layer is coated onto the fed core material to form an integrally formed body, and an article formed by this method is called an integral extrusion molded body.

[0016] 1, the integrally extruded product 10 of this embodiment has a rectangular prism shape with a cross section perpendicular to the extrusion direction. The integrally extruded product 10 has a metal core material 11 and a coating layer 13 that covers the entire outer surface of the core material, and further has an adhesive layer 12 interposed between the core material and the coating layer. Note that, hereinafter, when simply referring to a "cross section," this refers to a cross section perpendicular to the extrusion direction.

[0017] The core material 11 is made of a metal such as aluminum or an aluminum alloy, stainless steel, galvanized steel, or copper. From the viewpoints of achieving both the strength and lightness required for building components and the like, and of ease of processing into hollow or complex cross-sectional shapes, the core material is preferably made of aluminum or an aluminum alloy. Specifically, a material with good extrusion formability, such as that used for aluminum sashes, such as alloy numbers 6063 and 6060 of JISH4100, is used.

[0018] The shape of the core material 11 is not particularly limited as long as it allows the coating layer 13 to be formed on the surface by integral extrusion molding and has an internal space. The core material may be, for example, a rectangular pillar or a cylindrical column, and may have a U-shaped or C-shaped cross section. Furthermore, a partition wall 14 extending in the longitudinal direction may be formed inside the core material for reinforcement.

[0019] The thickness of the core material 11 is preferably 0.8 to 5.0 mm, more preferably 1.1 to 3.0 mm. When the core material is made of aluminum or an aluminum alloy, it is particularly preferable that the thickness of the core material be within the above range from the viewpoints of rigidity and extrusion processability. The dimensions of the entire core material, such as length and width, are not particularly limited and can be set depending on the application of the integrally extruded molded product. When rigidity and surface decoratability as a building component are required, the height and width of the cross section of the core material are preferably 20 mm or more, more preferably 30 mm or more, and preferably 200 mm or less.

[0020] The core material 11 is preferably knurled and / or anodized on its surface to further improve adhesion to the coating layer 13 or adhesive layer 12. Knurling is a process for forming grooves on the outer surface of the core material, thereby improving adhesion between the coating layer or adhesive layer and the core material. For example, knurling forms grooves along the longitudinal direction of the core material. The depth of the knurled grooves is preferably 0.03 to 1.0 mm, and the groove pitch is preferably 0.03 to 1.5 mm. The groove shape can be, for example, a series of approximately triangular or arc-shaped convex and concave portions. Anodizing is a process for forming a metal oxide film on the surface of the core material. Since the anodized film has fine pores extending from the surface in the thickness direction, using it without a pore-sealing treatment also improves adhesion between the coating layer or adhesive layer and the core material. When both knurling and anodizing are performed, it is preferable to perform the anodizing treatment after the knurling treatment.

[0021] In this embodiment, the coating layer 13 covers the entire outer surface of the core material 11 via the adhesive layer 12. The coating layer 13 only needs to cover at least the portion of the outer surface of the core material that may come into contact with bare skin when the integrally extruded product 10 is in use. The coating layer contains a base resin, wood flour, a colorant, and a foaming agent. The base resin is preferably a polyolefin resin.

[0022] Examples of polyolefin resins include polyethylene, polypropylene, and ethylene-propylene copolymers. The reason for using polyolefin resins is that they have excellent weather resistance when used outdoors. Preferred polyolefin resins are polyethylene and polypropylene, and a particularly preferred polyolefin resin is polypropylene, which has an excellent wood-like texture after sanding.

[0023] The polyolefin resin is preferably modified with an unsaturated carboxylic acid, as this improves compatibility with wood flour. Examples of unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, and crotonic acid, unsaturated dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, and derivatives thereof. Preferred unsaturated carboxylic acids are unsaturated dicarboxylic acids and their anhydrides, such as maleic acid and maleic anhydride. The content of unsaturated carboxylic acid in the unsaturated carboxylic acid-modified polyolefin resin is preferably 0.1 to 15% by weight based on the total monomer content of the unsaturated carboxylic acid-modified polyolefin resin.

[0024] Alternatively, an unsaturated carboxylic acid may be contained as a component separate from the polyolefin resin or unsaturated carboxylic acid-modified polyolefin resin. The purpose, like the unsaturated carboxylic acid modification, is to improve the compatibility between the polyolefin resin and wood flour. Preferred unsaturated carboxylic acids are unsaturated dicarboxylic acids and their anhydrides, such as maleic acid and maleic anhydride. The content of the unsaturated carboxylic acid contained as a component separate from the polyolefin resin is preferably 0.2 to 10 parts by weight per 100 parts by weight of the polyolefin resin.

[0025] The polyolefin resin preferably has a melting point of 165°C or less, particularly 125 to 165°C. From the viewpoint of ease of integral extrusion molding, the polyolefin resin preferably has an MFR (melt flow rate) of 3 to 25 g / 10 min, more preferably 3 to 15 g / 10 min. The melting point can be measured by known differential scanning calorimetry. The MFR is the value at 190°C and a load of 2.16 kgf, and can be measured in accordance with JIS K7210.

[0026] Even when a polyolefin resin is used as the base resin, the base resin may contain a resin other than a polyolefin resin. Examples of such a resin include acrylonitrile butadiene styrene resin. When the base resin contains a resin other than a polyolefin resin, the proportion of the polyolefin resin in the total resin is preferably 90% by weight or more. More preferably, the resin component of the base resin consists solely of a polyolefin resin.

[0027] The coating layer 13 contains wood flour to impart an excellent appearance and feel. Wood flour is often made from wood such as cedar, cypress, and western hemlock, as well as crushed scraps and waste wood of such wood, sawdust, etc., with particle sizes of 10 to 500 mesh, but more preferably 60 to 100 mesh. Using crushed scraps and waste wood as wood flour is preferable because it reduces environmental impact. The wood flour content is 5 to 50 parts by weight, preferably 10 to 40 parts by weight, per 100 parts by weight of the polyolefin resin.

[0028] The expansion ratio of the coating layer 13 is 1.5 times or more, preferably 2.1 times or more. This is because the higher the expansion ratio, the less hot the coating layer feels when touched at a high temperature. On the other hand, the expansion ratio of the coating layer is 3.5 times or less, preferably 3.0 times or less. Assuming that the thickness of the coating layer is within the range described below, if the expansion ratio is too high, the hardness of the coating layer will be low, and the coating layer will be dented when pressed with a finger or when walking on it. This is because the tactile sensation of the dented surface of the integrally extruded product will not match the sensation expected from the wood-like appearance, and people will feel uncomfortable.

[0029] The blowing agent used to expand the coating layer 13 may be a solid blowing agent that decomposes at the extrusion temperature to generate gas, such as sodium bicarbonate (sodium bicarbonate), ammonium carbonate, azodicarboxylic acid amide, or benzenesulfonyl hydrazide. However, it is preferable to use heat-expandable microspheres, such as so-called heat-expandable microcapsules, in which a blowing agent that vaporizes upon heating is encapsulated within a thermoplastic resin shell. Because wood flour is mixed into the resin in the coating layer of this embodiment, bubbles tend to break when gas is used with sodium bicarbonate or the like. In contrast, when heat-expandable microspheres are used as the blowing agent, bubbles are difficult to break and air bubbles remain, resulting in low thermal conductivity. Heat-expandable microspheres with an average diameter of preferably 8 to 40 μm, more preferably 10 to 15 μm, are used. This is because they can achieve a sufficient expansion ratio while maintaining the wood-like appearance. Commercially available heat-expandable microspheres can be used.

[0030] The coating layer 13 contains a colorant to impart a wood-like color. Known inorganic or organic pigments can be used as the colorant. The content of the colorant is preferably 2 to 8 parts by weight per 100 parts by weight of the polyolefin resin.

[0031] To enhance various physical properties, the coating layer 13 may contain various additives conventionally used in synthetic resins, such as fillers, UV absorbers, antistatic agents, matting agents, mica powder, organic fibers, vermiculite powder, glass chips, waste paper powder, and ceramic powder. Examples of fillers that can be used include calcium carbonate and talc. However, even when additives are added, their content is preferably 20% by weight or less, more preferably 5% by weight or less, based on the resin components. This is because the thermal conductivity of the coating layer increases when a large amount of additives, particularly fillers with high thermal conductivity, is added.

[0032] The thickness of the coating layer 13 is 3.0 mm or more, preferably 3.1 mm or more. This is because the thicker the coating layer, the less hot it feels when touched at a high temperature. On the other hand, the thickness of the coating layer is 8.0 mm or less, preferably 5.0 mm or less. Assuming that the expansion ratio of the coating layer is within the above-mentioned range, if the coating layer is too thick, the hardness of the coating layer will be low, and the coating layer will dent when pressed with a finger or when walking on it.

[0033] The surface of the coating layer 13 is sanded. Sanding is a process of roughening the surface using a file, emery paper, sand, or the like. After extrusion molding, a layer (skin layer) with a lower expansion ratio than the interior is formed on the outermost surface of the coating layer due to sliding with the mold (die). In this embodiment, this skin layer is removed by sanding. The sanding should be performed at least on the portion of the coating layer surface that may come into contact with a person's bare skin when using the integrally extruded body 10.

[0034] The adhesive layer 12 is formed on the entire outer surface of the core material between the core material 11 and the covering layer 13. Although the adhesive layer can be omitted, it is preferable to provide the adhesive layer between the core material 11 and the covering layer 13 in order to increase the adhesive strength between them.

[0035] The composition of the adhesive layer 12 is not particularly limited as long as it can bond the core material 11 and the coating layer 13, but it preferably contains an epoxy group-containing polyolefin resin, which is a copolymer of an α-olefin and an epoxy group-containing unsaturated monomer. Examples of the α-olefin include the same monomers as the α-olefins that constitute the polyolefin resin contained in the coating layer. Examples of the epoxy group-containing unsaturated monomer include glycidyl (meth)acrylates such as glycidyl acrylate and glycidyl methacrylate. Of these, glycidyl (meth)acrylate is preferred. Epoxy group-containing polyolefin resins that can be used for the adhesive layer 12 are described in detail in Japanese Patent Application Laid-Open No. 11-254569.

[0036] From the viewpoints of heat resistance and extrusion moldability, the epoxy group-containing polyolefin resin of the adhesive layer 12 preferably has a melting point of 50 to 105° C., particularly 90 to 100° C. From the viewpoint of integral extrusion molding, the MFR of the epoxy group-containing polyolefin resin is preferably 1 to 20 g / 10 min, and more preferably 3 to 10 g / 10 min.

[0037] The thickness of the adhesive layer is not particularly limited as long as the object of the present invention is achieved, but from the viewpoint of adhesion and productivity, and to prevent the adhesive layer from breaking, peeling, etc. during bending processing, the thickness is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.5 mm.

[0038] Next, a method for producing the integrally extruded body 10 of this embodiment will be described.

[0039] The integrated extrusion molding machine 20 shown in Figure 2 is equipped with two extruders 21 and 23, and while inserting a core material 11 through the openings of dies 22 and 24 and feeding it in one direction (to the left in Figure 2), a resin composition is extruded at each die, and the core material is successively coated with an adhesive layer 12 and a coating layer 13.

[0040] The adhesive layer 12 is formed by coating the surface of the core material 11 with the adhesive composition extruded from the first extruder 21 in the first die 22. The adhesive layer may be formed by integral extrusion molding or by applying the adhesive to the surface of the core material in advance by spraying, dipping, or the like.

[0041] The covering layer 13 is formed by coating the adhesive layer 12 with the resin composition kneaded in the second extruder 23 in the second die 24. At this time, the foaming agent contained in the covering layer foams.

[0042] The extrusion 10 is then cooled to harden the coating layer 13. The surface of the extrusion is sanded and cut to the required size. [Example]

[0043] The integrally extruded body of this embodiment will be described in more detail based on various experimental results. Note that, in the following, "%" indicating the content of each component means % by mass.

[0044] First, integrally extruded molded articles were produced by varying the composition of the coating layer and the expansion ratio, and the heat felt when they came into contact with bare skin at high temperatures was evaluated in the laboratory.

[0045] A hollow aluminum alloy core material with a roughly rectangular cross section was manufactured by extrusion molding. The core material was knurled to form longitudinal grooves (0.5 mm pitch, 0.1 mm depth), and then an oxide film was formed by anodizing (sulfuric acid method, without sealing).

[0046] For the adhesive layer, Bondfast (registered trademark) 7B (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate-vinyl acetate (copolymerization ratio (mass ratio) 83:12:5), MFR 7g / 10min, melting point 95°C) was used as an epoxy group-containing polyolefin resin.

[0047] The coating layer was made from pellets of maleic acid-modified polypropylene resin (maleic acid content approximately 2% by weight, melting point 150°C, MFR approximately 10g / min), wood flour masterbatch (wood flour particle size 100 mesh or less, wood flour:polypropylene = 68:32 (mass ratio)), light brown colorant, and masterbatch of thermally expandable microsphere-type blowing agent (outer resin: acrylic copolymer, average particle size: 10-15μm, microspheres:polyethylene = 50:50 (mass ratio)). Each of these was mixed in a specified ratio. The blowing agent was selected after evaluating surface roughness and cross-sectional structure uniformity in preliminary tests.

[0048] Using the above materials and compositions, integral extrusion molded bodies of Samples 1 to 10 were produced by the method described in the embodiment. The core material 11 was preheated to approximately 100°C just before insertion into the adhesive layer die. The extrusion conditions were as follows: First extruder 21 (for adhesive layer): Single-screw extruder (extrusion temperature: approximately 140°C) Second extruder 23 (for coating layer): Single-screw extruder (extrusion temperature: approximately 190°C)

[0049] After integral extrusion molding, the molded body was cooled in a water-cooling jacket (not shown), and the surface was sanded with a belt sander with grit size #40 that rotated in the direction opposite to the direction of movement of the molded body.

[0050] The produced integral extrusion molded body was kept in an oven at 84°C for about 2 hours, then removed from the oven, and the heat felt by touching with a finger was evaluated.

[0051] Table 1 shows the sample preparation conditions and evaluation results. In the table, "PP" indicates the combined amount of maleic acid-modified polypropylene resin and polypropylene contained in the wood flour master batch, "wood flour" indicates the wood flour contained in the wood flour master batch, and "foaming agent batch" indicates the amount of foaming agent master batch. Sample 1 does not contain a foaming agent. "Sanding" indicates the grit size (grit) of the sandpaper used for sanding. The symbols in the "evaluation results" have the following meanings: A: It is possible to continue touching it. B: It is possible to touch it for a short time (3 to 30 seconds) D: Almost impossible to touch

[0052] [Table 1]

[0053] From the results in Table 1, the higher the expansion ratio and the thicker the coating layer, the lower the degree of heat felt by the finger. However, in samples 8 to 10 (coating layer thickness of 5 to 6 mm), the degree of heat felt was low, but as mentioned above, when the surface was pressed with a finger, the coating layer felt like it was denting.

[0054] Next, integral extrusion moldings of samples 11 to 17 were prepared in the same manner as above, and for comparison, they were left in an actual sauna room for 60 minutes along with commercially available building materials (samples 18 to 21), and the heat felt by touching them with a finger was evaluated.

[0055] Table 2 shows the sample preparation conditions and evaluation results. The composition ratio of each raw material in the coating layer is shown. The wood flour content of samples 18 to 20 is based on the manufacturer's data. The surface temperature of the component at the time of evaluation was 78°C. The symbols used in the evaluation results have the following meanings. Please note that the heating conditions and evaluation criteria differ between Tables 1 and 2. A: It is possible to continue touching it. B: It is possible to touch it for a short time (10 to 30 seconds) C: Can be touched for a short time (3-10 seconds) D: Almost impossible to touch

[0056] [Table 2]

[0057] From the results in Table 2, it was possible to touch all of Samples 12 to 17 with bare skin in a sauna room. If Samples 12 to 17 were used as flooring or decking materials in a sauna room, it would be possible to walk on them with bare feet, and it can be determined that there would be at least no risk of burns. In particular, Sample 17 could be touched continuously with the fingers, just like wood (Sample 21). Furthermore, none of Samples 11 to 21 felt like their surfaces were indented when pressed with the fingers.

[0058] The present invention is not limited to the above-described embodiments and examples, and various modifications are possible within the scope of the technical concept thereof. [Industrial Applicability]

[0059] The metal core-containing integrally extruded product of the present invention can be used as architectural components such as architectural decorative materials, architectural handrails, security grilles, louvers, etc., as well as components for furniture, fixtures, lighting fixtures, etc. In particular, it can be preferably used for applications where the surface temperature is high and where people are expected to walk on it barefoot, such as flooring and bench materials used outdoors, such as on verandas and decks in school facilities and homes, and flooring materials used in high-temperature and high-humidity environments, such as sauna rooms. [Explanation of symbols]

[0060] 10. Integral extrusion molding 11 Core material 12 Adhesive layer 13 Covering layer 14 Partition Wall 20 Integrated extrusion molding machine 21 First extruder (for adhesive layer) 22 First die (for adhesive layer) 23 Second extruder (for coating layer) 24 Second die (for coating layer)

Claims

1. A core material having an internal space and a coating layer that covers at least a part of the outer surface of the core material, the coating layer contains a resin, wood flour, a foaming agent, and a colorant, has an expansion ratio of 1.5 to 3.5 times, a thickness of 3.0 to 8.0 mm, and has at least a part of its surface subjected to sanding; One-piece extrusion molding.

2. The foaming agent is heat-expandable microspheres having a structure in which a blowing agent that vaporizes when heated is encapsulated in an outer shell made of a resin. The integrally extruded article according to claim 1 .

3. The expansion ratio of the coating layer is 2.1 to 3.0 times. The integrally extruded article according to claim 1 or 2.

4. The thickness of the coating layer is 3.1 to 5.0 mm. The integrally extruded article according to any one of claims 1 to 3.

5. The core material is made of aluminum or an aluminum alloy. The integrally extruded article according to any one of claims 1 to 4.

6. Further, an adhesive layer is provided between the core material and the coating layer. The integrally extruded article according to any one of claims 1 to 5.

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