Resin-metal composite and method for producing same

Abstract

The present invention provides a resin-metal composite and a manufacturing method thereof, which can bond the outer peripheral surface of a metal core material and a coating layer made of a wood-resin composite material with higher adhesive strength by a simple method. [Solution] A resin-metal composite comprising a surface-treated metal core material 10 and a coating layer 30 made of a wood-resin composite material coated on the outer peripheral surface of the core material 10, the outer peripheral surface of the core material 10 being coated with a pseudo-rough surface layer 20 made of a water-based resin, the outer peripheral surface of the pseudo-rough surface layer 20 being dehydrated by rapid drying of the water-based resin and roughened into an uneven shape, the coating layer 30 made of a wood-resin composite material being laminated on the outer peripheral surface of the core material 10 via the pseudo-rough surface layer 20, and fixed by a combination of the physical adhesive action and the chemical adhesive action of the pseudo-rough surface layer 20.

Description

Technical Field

[0001] The present invention relates to a resin-metal composite coated with a coating layer made of a synthetic resin mixed with wood powder on the surface of a metal material, and more particularly to a resin-metal composite in which a coating layer made of a synthetic resin is firmly coated on a metal material and a method for manufacturing the same.

Background Art

[0002] General building materials are made of solid wood. However, solid wood requires maintenance, and even when coated with a weather-resistant coating such as paint or varnish as a measure against deterioration caused by weather exposure, etc., the protection period is relatively short.

[0003] In recent years, as an alternative building material to wood, a wood-plastic composite (WPC) manufactured by mixing wood powder (filler) and resin has been used as an interior building material or an exterior building material with excellent design. Since the wood-plastic composite contains a large amount of wood powder, when it is commercialized as a building material, it is heavier than wood, and when it has a hollow structure, it is vulnerable to water and impact, and the wood-plastic composite is prone to breakage.

[0004] In order to solve the strength problem, a coated structure has been proposed in which a cylindrical coating body is formed in advance from a wood-plastic composite and a steel material such as a C-shaped steel or a square steel pipe is inserted into the coating body. This coated structure not only has a high manufacturing cost, but also the operation of inserting the steel material into the coating body is very difficult. Furthermore, since a gap is generated between the coating body and the steel material, the coating body is prone to breakage when an impact is applied.

[0005] In order to avoid the problems of the coated structure, a resin-metal composite with improved adhesion to the coating has been proposed in Patent Document 1. Patent Document 1 discloses a resin-metal composite in which a coating made of a wood resin composite material is formed on the surface of a thin or thick metal material by applying a primer or plasma treatment to the surface of the metal material and then applying a wood resin composite material containing a coupling agent.

[0006] When a thermosetting resin (e.g., epoxy resin) suitable for adhesion to a metal material is used alone as the primer base material, the adhesion to the wood resin composite material becomes weak. Therefore, as described in Patent Document 1, as the base material, two types of resins, a thermosetting resin (e.g., epoxy resin, melamine resin) suitable for adhesion to a metal material and a thermoplastic resin (e.g., methyl cellulose, polyvinyl acetate resin) suitable for adhesion to a wood resin composite material, are mixed and used.

[0007] In the surface treatment of a metal material by plasma, physical roughening is performed on the surface of the metal material by irradiating the entire surface of the metal material with plasma in an environment where the pressure of the plasma gas (argon) is adjusted.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] The resin-metal composite disclosed in Patent Document 1 has the following problems. <1> Since the physical properties, melting conditions, etc. of the thermosetting resin and the thermoplastic resin are different, it is technically difficult to mix and use different types of resins. <2>When two types of primer resins are mixed and used, mixing unevenness is likely to occur depending on the mixing conditions and the like. If the primer is applied with the mixing unevenness remaining, variations in adhesiveness will occur, leading to poor adhesion. <3>If poor adhesion occurs due to the factors described above, the bonded part is likely to peel off due to impacts, temperature shrinkage, etc. during use, ultimately including the problem that the surface coating layer is likely to be damaged. <4>When applying a primer for the surface treatment of a metal material, if the primer is applied thickly to avoid poor adhesion, the surface treatment cost will increase. <5>When using plasma treatment as a surface treatment method for a metal material, it is necessary to secure a pressure adjustment chamber for performing the plasma treatment, or to deploy plasma gas supply equipment and plasma irradiation equipment. Therefore, the plasma facility becomes large-scale, and the surface treatment cost of the metal material becomes very high.

[0010] The present invention has been made in view of the above points, and its object is to provide a resin-metal composite body and a method for manufacturing the same that can fix the outer peripheral surface of a metal core material and a coating layer made of a wood resin composite material with higher adhesion by a simple method.

Means for Solving the Problems

[0011] The present invention is a resin-metal composite body including a metal core material having a surface treatment and a resin coating layer coated on the outer peripheral surface of the core material, wherein the outer peripheral surface of the core material is coated with a pseudo-rough layer made of an aqueous resin, the outer peripheral surface of the pseudo-rough layer is dehydrated by rapid drying of the aqueous resin and roughened into an uneven shape, a coating layer is laminated on the outer peripheral surface of the core material via the pseudo-rough layer, and the coating layer is integrally fixed to the outer peripheral surface of the core material by combining the physical adhesion action through the uneven surface of the pseudo-rough layer and the chemical adhesion action between the resins of the pseudo-rough layer and the coating layer. In another aspect of the present invention, the aqueous resin is an aqueous dispersion or an aqueous emulsion. In another aspect of the present invention, the coating layer is composed of a wood resin composite material that is a mixture of wood powder and resin. The present invention is a method for manufacturing a resin-metal composite in which a concavo-convex surface treatment is applied to the outer peripheral surface of a metal core material, and a resin coating layer is coated on the outer peripheral surface of the core material. The method includes an aqueous resin coating step of applying an aqueous resin to the surface of the core material, a surface treatment step of rapidly drying the aqueous resin to form a pseudo-rough layer having a concavo-convex shape on the outer peripheral surface of the core material, a coating step of coating a coating layer on the outer peripheral surface of the core material through the pseudo-rough layer to form a resin-metal composite, and a cooling step of cooling the resin-metal composite. The coating layer is integrally fixed to the outer peripheral surface of the core material by using both a physical adhesion action through the concavo-convex surface of the pseudo-rough layer and a chemical adhesion action between the resins of the pseudo-rough layer and the coating layer. In another aspect of the present invention, in the surface treatment step of the core material, the rapid drying means for the aqueous resin is any one of a high-frequency induction heating device, a dielectric heating device, a hot air circulation furnace, and an infrared heating furnace. In another aspect of the present invention, in the coating step of the coating layer, a mold for coating a coating layer made of a wood resin composite material on the outer peripheral surface of the core material through the pseudo-rough layer is used. In another aspect of the present invention, an aqueous dispersion or an aqueous emulsion can be used as the aqueous resin. In another aspect of the present invention, the coating layer is composed of a wood resin composite material which is a mixture of wood powder and resin.

Advantages of the Invention

[0012] The present invention has at least one of the following effects. <1> In the present invention, by using both a physical fixing action utilizing the concavo-convex shape of the pseudo-rough layer made of an aqueous resin formed on the outer peripheral surface of the metal core material and a chemical fixing action utilizing the resin component of the pseudo-rough layer, the coating layer is fixed to the outer peripheral surface of the metal core material. Therefore, compared with the conventional chemical primer treatment method of applying a primer to the outer peripheral surface of the metal core material and the conventional physical primer treatment method of roughening the outer peripheral surface of the metal core material by performing concavo-convex processing, the fixing strength between the metal core material and the coating layer is significantly improved. <2>Since the adhesion strength between the core material and the coating layer is significantly improved, the durability of the coating layer against external impact forces, temperature shrinkage, etc. is higher than that of the prior art. <3>The pseudo-rough layer can be formed using an aqueous resin. This not only eliminates the need for the troublesome primer treatment that combines different types of resins as in the prior art, but also resolves problems such as uneven mixing of resins and variations in adhesion caused by such uneven mixing. <4>In the present invention, by simply rapidly drying an aqueous resin applied to the outer peripheral surface of a metal core material, a pseudo-rough layer can be formed economically on the flat outer peripheral surface of the core material, creating a pseudo-rough surface. Therefore, a large-scale plasma treatment facility is not required for the surface treatment of the metal core material.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Embodiments for Carrying Out the Invention

[0014] The present invention will be described in detail below with reference to the drawings.

[0015] <1>Overview of the resin-metal composite The resin-metal composite according to the present invention includes a metal core material 10, a pseudo-rough layer 20 integrally formed on the smooth outer peripheral surface (surface) of the core material 10, and a coating layer 30 made of a wood plastic composite (WPC) that covers the surface of the pseudo-rough layer 20. That is, in the present invention, the pseudo-rough layer 20 and the coating layer 30 are sequentially integrated and laminated on the surface of the core material 10.

[0016] <2>Metal core material The metal core material 10 is a strength member of the resin-metal composite and is made of a metal material.

[0017] <2.1>Examples of metal materials As the material of the metal core material 10, for example, known metal materials such as aluminum, stainless steel, iron, titanium alloy, zinc alloy, brass, etc. are applicable, and the metal material is appropriately selected according to the use of the resin-metal composite. When the resin-metal composite is used as an interior building material or an exterior building material, aluminum, which is lightweight and excellent in durability and workability, is preferable as the metal material.

[0018] <2.2>Cross-sectional shape of the core material The cross-sectional shape of the core material 10 can be appropriately selected according to the use of the resin-metal composite. Specific cross-sectional shapes of the core material 10 may be, for example, cylindrical or rod-shaped (the cross-sectional shape is circular, elliptical, polygonal, etc.), L-shaped or U-shaped, or plate-shaped. In this example, the form of a hollow cylinder in which the cross-section of the core material 10 has a square shape will be described.

[0019] <3>Pseudo-rough layer The pseudo-rough layer 20 is a rough layer made of an aqueous resin located between the core material 10 and the coating layer 30, and exhibits suitable adhesion to the core material 10 and the coating layer 30. In the present invention, the aqueous resin layer is transformed into a concavo-convex pseudo-rough layer 20 by rapidly drying the aqueous resin applied to the outer peripheral surface of the core material 10 to perform forced dehydration of the aqueous resin.

[0020] <3.1>Aqueous resin An aqueous dispersion or an aqueous emulsion is preferable as the aqueous resin.

[0021] <4>Coating layer In the present invention, the entire outer peripheral surface or a part of the outer peripheral surface of the core material 10 is coated with the coating layer 30 through the pseudo-rough layer 20 and fixed integrally. The coating layer 30 is made of a known wood resin composite material (WPC) which is a mixture of wood powder (filler) and resin. The wood powder may be any one kind of organic wood powder (wood powder, wood pellets, wood fibers, etc.) or inorganic filler (talc, calcium carbonate, wollastonite or kaolinite, etc.) or a mixture thereof.

[0022] [Manufacturing method] Next, with reference to FIGS. 2 and 3, the manufacturing method of the resin-metal composite will be described in detail. The resin-metal composite is manufactured through a "surface processing step (S10)", a "coating step of the coating layer (S20)", and a "cooling step (S30)". When manufacturing the resin-metal composite on a production line, the core material 10 may be sequentially conveyed to each step through a known feeding device.

[0023] <1> Preparation of the core material Prepare core materials 10 with various cross-sectional shapes. In this example, the form of the core material 10 having a hollow structure with a square cross-section will be described. Supply the metal core material 10 to the surface processing step through the feeding device 40. The metal core material 10 is used in a smooth state without roughening its outer peripheral surface.

[0024] <2> Surface processing step of the core material (S10) In the present invention, the core material 10 is surface-processed by applying an aqueous resin to its outer peripheral surface and rapidly drying the applied aqueous resin. <2.1> Application of the aqueous resin Apply a solution of the aqueous resin to the outer peripheral surface of the metal core material 10 to form a film.

[0025] <2.1.1> Thickness of the film of the aqueous resin The coating thickness of the film of the aqueous resin is appropriately selected according to the use of the resin-metal composite.

[0026] <2.1.2> Coating means (coating device) of the aqueous resin As the aqueous resin coating device 50, it can be applied using spraying, a coating roller, a brush, or the like. In practice, the coating device 50 can apply a known spraying method. By using the spraying type coating device 50, the aqueous resin can be uniformly applied over the entire outer peripheral surface of the core material 10.

[0027] After finishing the coating process of the aqueous resin, the core material 10 is supplied to the surface processing process.

[0028] <2.2> Rapid drying (formation of a pseudo-rough layer) Next, the aqueous resin is rapidly heated and dehydrated by the rapid drying device 60 to transform the aqueous resin layer applied to the outer peripheral surface of the core material 10 into a pseudo-rough layer 20.

[0029] <2.2.1> Purpose of rapid drying Rapid drying is not for shortening the curing time of the aqueous resin, but for removing the moisture contained in the aqueous resin to form the pseudo-rough layer 20. By forming the pseudo-rough layer 20 on the flat outer peripheral surface of the core material 10, the outer peripheral surface of the core material 10 is formed as a pseudo-concavo-convex surface. Just by rapidly drying the aqueous resin, there is no need to directly perform physical roughing on the outer peripheral surface of the core material 10.

[0030] Thus, in the present invention, by simply rapidly drying the aqueous resin applied to the outer peripheral surface of the core material 10, only by forming the pseudo-rough layer 20 on the outer peripheral surface of the core material 10, a pseudo-concavo-convex surface can be formed on the outer peripheral surface of the core material 10. Therefore, there is no need to directly perform roughing on the outer peripheral surface of the core material 10 by physical roughing means such as plasma processing or shot blasting.

[0031] <2.2.2> Drying means by heating (rapid drying device) Simply allowing the aqueous resin to dry naturally over a long period of time makes it difficult to form the aqueous resin into a rough surface. As a result of intensive research in the present invention, it has been found that the aqueous resin layer can be roughened by rapidly drying the aqueous resin layer to achieve forced dehydration in a short time.

[0032] As the quick-drying device 50 which is a means for rapidly drying the aqueous resin layer, for example, conventionally known heating means such as a high-frequency induction heating device, a dielectric heating device, a hot air circulation furnace, an infrared heating furnace, etc. can be used. Since the energy efficiency of infrared heating is around 30%, while the energy efficiency of high-frequency induction heating is 70% or more, a high-frequency induction heating device is preferable.

[0033] When rapidly drying the aqueous resin using a high-frequency induction heating device, the frequency and heating time are appropriately selected in consideration of the coating thickness of the aqueous resin and the like.

[0034] <2.2.3> Structure of the pseudo-roughened layer FIG. 4A and FIG. 4B show micrographs of the surface of the pseudo-roughened layer 20. As seen in the micrographs, cracked deep grooves 21 presenting a tortoise shell pattern are formed on the surface of the pseudo-roughened layer 20. The deep grooves 21 are formed by the shrinkage of the aqueous resin by rapidly drying the aqueous resin.

[0035] <2.2.4> Heating temperature and heating time When using a high-frequency induction heating device, the frequency (heating temperature) and heating time are appropriately selected in consideration of the components and thickness of the aqueous resin and the like.

[0036] <2.2.5> Adhesion force between the core material and the pseudo-roughened layer The aqueous resin adheres to the outer peripheral surface of the core material 10 by its self-adhesive force. Since the pseudo-roughened layer 20 is formed by the alteration of the aqueous resin adhered to the outer peripheral surface of the core material 10, the adhesion force between the outer peripheral surface of the core material 10 and the back surface of the pseudo-roughened layer 20 is enhanced. After finishing the surface treatment of the core material 10, the core material 10 is supplied toward the coating process of the coating layer.

[0037] <3> Coating process of the coating layer (S20) A coating layer 30 made of a wood plastic composite (WPC) is formed on the surface of the core material 10 covered with the pseudo-rough layer 20.

[0038] <3.1> Thickness of the coating layer The thickness of the coating layer 30 is appropriately selected according to the use of the resin-metal composite.

[0039] <3.2> Forming means of the coating layer For example, the coating layer 30 can be coated on the surface of the pseudo-rough layer 20 using a mold 60 and an extrusion device 61. The mold 60 has a structure that allows the core material 10 to be inserted therethrough, and an extrusion device 61 is integrally assembled to a part of the mold 60, and is configured to be able to extrude the wood plastic composite material into the mold 60 in a molten state through the extrusion device 61.

[0040] <3.3> Forming method of the coating layer While supplying the core material 10 with the pseudo-rough layer 20 formed therein into the mold 60, the supply of the wood plastic composite material in a molten state into the mold 60 is started through the extrusion device 61. The discharge amount and discharge pressure of the wood plastic composite material are appropriately selected in consideration of the supply speed of the core material 10, the thickness of the coating layer 30, etc.

[0041] In the mold 60, the outer peripheral surface of the pseudo-rough layer 20 is coated with the wood plastic composite material to form a coating layer 30 having a predetermined thickness. As described above, the coating layer 30 firmly adheres to the outer peripheral surface of the core material 10 via the pseudo-rough layer 20.

[0042] <3.4> Adhesion strength (bonding strength) between the pseudo-rough layer and the coating layer Fig. 3 shows an enlarged view of the cross section of the pseudo-rough layer 20. In addition to the formation of deep grooves 21 in a tortoise shell pattern in the pseudo-rough layer 20, minute uneven surfaces 22 are formed on the surface of the pseudo-rough layer 20 as evaporation traces of moisture.

[0043] The outer peripheral surface of the core material 10 is formed as an uneven surface via the pseudo-rough layer 20. Therefore, since the coating layer 30 enters the deep grooves 21 and the uneven surface 22 of the pseudo-rough layer 20 to exert an anchor effect, the pseudo-rough layer 20 and the coating layer 30 are physically fixed to each other. Furthermore, since the aqueous resin component constituting the pseudo-rough layer 20 and the resin component constituting the coating layer 30 react and fuse, the pseudo-rough layer 20 and the coating layer 30 are chemically fixed to each other. In this way, in the present invention, since the physical fixing means and the chemical fixing means simultaneously exhibit the fixing function, the pseudo-rough layer 20 and the coating layer 30 can be firmly fixed to each other. Therefore, in the present invention, compared with the conventional chemical primer application method for applying a primer to the outer peripheral surface of the metal core material 10 and the conventional physical primer application method for roughening the outer peripheral surface of the metal core material 10 by uneven processing, the fixing strength between the metal core material 10 and the coating layer 30 made of a wood resin composite material is significantly improved.

[0044] In particular, since the fixing area by the chemical fixing surface is formed and increased along the outer peripheral surfaces of the deep grooves 21 and the uneven surface 22, a greater fixing force can be exerted compared to the case of joining without the presence of the deep grooves 21 or the uneven surface 22.

[0045] <4> Cooling step (S30) The resin-metal composite produced by covering the outer peripheral surface of the pseudo-rough layer 20 with the coating layer 30 is cooled. The cooling device 70 may be either air cooling means (forced air cooling) or water cooling means (immersion cooling). The cooling step is not limited to forced cooling using the cooling device 70, and natural cooling can also be applied.

Explanation of reference numerals

[0046] 10 ···· Metal core material 20 ···· Pseudo-rough layer made of aqueous resin 20a ··· Aqueous resin 21 ···· Deep groove 22 ···· Uneven surface 30 ···· Coating layer 40 ···· Coating device 50 ···· Quick-drying device 60 ···· Mold 61 ···· Extrusion device 70 ···· Cooling device

Claims

1. A resin-metal composite body comprising a surface-treated metal core and a resin coating layer coated on the outer peripheral surface of the core, The outer peripheral surface of the core material is coated with a pseudo-rough surface layer made of a water-based resin, the outer peripheral surface of the pseudo-rough surface layer is dehydrated by rapid drying of the aqueous resin and roughened to have an uneven surface; A coating layer is laminated on the outer peripheral surface of the core material via the pseudo-rough surface layer, The coating layer is integrally fixed to the outer peripheral surface of the core material by a combination of a physical adhesive action via the uneven surface of the pseudo-rough surface layer and a chemical adhesive action between the resins of the pseudo-rough surface layer and the coating layer. Resin metal composite.

2. 2. The resin-metal composite according to claim 1, wherein the aqueous resin is an aqueous dispersion or an aqueous emulsion.

3. 2. The resin-metal composite according to claim 1, wherein the coating layer is made of a wood-resin composite material which is a mixture of wood powder and resin.

4. A method for producing a resin-metal composite, comprising: providing an outer peripheral surface of a metal core material with an uneven surface treatment; and coating the outer peripheral surface of the core material with a resin coating layer, a step of applying an aqueous resin to a surface of the core material; a surface processing step of the core material, in which the aqueous resin is rapidly dried to form a pseudo-rough surface layer having an uneven shape on the outer peripheral surface of the core material; A coating step of coating a coating layer on the outer peripheral surface of the core material via the pseudo-rough surface layer to form a resin-metal composite; A cooling step of cooling the resin-metal composite, The coating layer is integrally fixed to the outer peripheral surface of the core material by a combination of a physical adhesive action via the uneven surface of the pseudo-rough surface layer and a chemical adhesive action between the resins of the pseudo-rough surface layer and the coating layer. A method for producing a resin-metal composite.

5. The method for producing a resin-metal composite according to claim 4, characterized in that in the surface treatment process of the core material, the rapid drying means for the aqueous resin is any one of a high-frequency induction heating device, a dielectric heating device, a hot air circulating furnace, and an infrared heating furnace.

6. The method for producing a resin-metal composite according to claim 4, characterized in that in the coating step, a mold is used to coat the outer peripheral surface of the core material with a coating layer made of a wood-resin composite material via a pseudo-rough surface layer.

7. 5. The method for producing a resin-metal composite according to claim 4, wherein the aqueous resin is an aqueous dispersion or an aqueous emulsion.

8. The method for producing a resin-metal composite body according to claim 4, wherein the coating layer is a wood-resin composite material which is a mixture of wood powder and resin.

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