Resin member

Abstract

This resin member comprises a photocatalyst coating film on a surface of a resin base material.　The photocatalyst coating film has a sea-island structure in which anatase-type titanium oxide particles are dispersed in an island form in the sea of a metal material, and thus can provide a resin member with a photocatalyst coating film that achieves both high photocatalytic effect and prevention of deterioration of the resin base material.

Description

Resin parts

[0001] The present invention relates to a resin member, and more particularly to a resin member having self-cleaning properties.

[0002] Titanium oxide has a photocatalytic effect that causes oxidation when exposed to light energy, and can oxidize and decompose organic matter such as pollutants and odorous substances.It also exhibits antibacterial and antiviral effects, so by coating the surface of a component with titanium oxide, it can impart self-cleaning properties that keep the surface clean.

[0003] The photocatalytic effect of titanium oxide is higher when the crystal structure is anatase than when it is rutile, and the anatase titanium oxide transforms to the rutile structure at temperatures above 700° C., resulting in a decrease in the photocatalytic effect.

[0004] Patent Document 1 discloses that by increasing the particle size of titanium oxide particles through granulation, it is possible to suppress the transformation of titanium oxide from anatase to rutile due to heat during thermal spraying, and to improve the remaining proportion of anatase titanium oxide.

[0005] Japanese Patent No. 3944551

[0006] However, the photocatalytic coating material described in Patent Document 1 does not sufficiently suppress the transition of titanium oxide to the rutile type, resulting in low photocatalytic effect and deterioration of the resin substrate due to the oxidizing action of titanium oxide.

[0007] The present invention has been made in view of the problems associated with the prior art, and its object is to provide a resin member provided with a photocatalytic coating that has a high photocatalytic effect on the surface and can prevent deterioration of the resin substrate.

[0008] As a result of extensive research into achieving the above-mentioned object, the inventors discovered that the above-mentioned object can be achieved by forming a photocatalytic coating with a sea-island structure in which anatase titanium oxide particles are dispersed like islands in a sea of ​​metal material, and thus completed the present invention.

[0009] That is, the resin member of the present invention has a photocatalytic coating on the surface of a resin substrate, and is characterized in that the photocatalytic coating has a sea-island structure in which anatase-type titanium oxide particles are dispersed in the form of islands in a sea of ​​metal material.

[0010] The method for producing a resin member of the present invention is a method for producing the above-mentioned resin member, and is characterized by comprising a coating step of spraying unmolten raw material particles onto the surface of the resin substrate to form a photocatalytic coating, the raw material particles including metal-plated anatase type titanium oxide particles and metal particles, the coating step comprising a treatment of lowering the temperature of the raw material particles impinging on the resin substrate to 100 to 150°C, and a further step of polishing and / or grinding the surface of the formed photocatalytic coating to expose the anatase type titanium oxide particles.

[0011] According to the present invention, the photocatalytic coating has a sea-island structure in which anatase-type titanium oxide particles are dispersed like islands in a sea of ​​metal material, making it possible to provide a resin part provided with a photocatalytic coating that achieves both a high photocatalytic effect and prevention of deterioration of the resin substrate.

[0012] 1 is a cross-sectional view showing an example of the structure of a resin member of the present invention.

[0013] <Resin Member> The resin member of the present invention will be described in detail below. The resin member of the present invention comprises, on the surface of a resin substrate, a photocatalytic coating having a sea-island structure in which anatase titanium oxide particles are dispersed in the form of islands in a sea of ​​metal material.

[0014] As shown in FIG. 1, in the photocatalytic coating of the present invention, anatase type titanium oxide particles are dispersed like islands in a sea of ​​metal material, and the anatase type titanium oxide particles are surrounded by the metal material.

[0015] Therefore, light incident on the photocatalytic coating is reflected by the sea of ​​metal material and does not penetrate to the vicinity of the resin substrate, so even if the titanium oxide particles are present in the vicinity of the resin substrate, deterioration of the resin substrate due to the oxidizing action of the titanium oxide particles can be prevented.

[0016] In the present invention, a sea of ​​metallic material means that metallic materials are joined together and are continuous, and the joining may be not only metallurgical joining but also mechanical joining, and does not mean that there are no interfaces or voids in the metallic material.

[0017] The photocatalytic coating can be formed by cold spraying raw material particles containing metal-plated anatase titanium oxide particles and metal particles onto a resin substrate.

[0018] The cold spray method is a method of forming a coating by causing raw material particles in a solid state to collide with a substrate using a supersonic flow of a working gas without melting or gasifying the raw material particles.

[0019] According to this cold spray method, a photocatalytic coating can be formed at low temperatures, and unlike other thermal spray methods, there is no need to heat the anatase type titanium oxide particles above their transition temperature. This prevents the titanium oxide particles from transitioning from anatase type to rutile type, and a high photocatalytic effect can be obtained.

[0020] The Vickers hardness of the metal material is preferably 700 (Hv) or less, more preferably 500 (Hv) or less, and even more preferably 400 (Hv) or less.

[0021] The metal material also serves as a binder for forming the photocatalytic coating, and when the Vickers hardness of the metal material is 700 (Hv) or less, the metal particles that make up the sea of ​​the metal material undergo significant plastic deformation upon collision, thereby improving the strength of the coating.

[0022] In other words, since the above-mentioned metal material is ductile and malleable and can be plastically deformed, the metal particles that form the sea of ​​metal material sprayed onto the resin substrate by the cold spray method sink into the resin substrate, undergo plastic deformation and adhere, forming irregular irregularities at the interface with the resin substrate and bonding by an anchor effect.

[0023] The metal particles that penetrate into these irregularities and adhere closely to the resin substrate not only bond to the resin substrate, but also undergo plastic deformation due to subsequent collisions with metal particles and metal-plated titanium oxide particles, thereby catching and holding these subsequently colliding raw material particles and preventing them from bouncing back.

[0024] Therefore, in the photocatalytic coating formed by the cold spray method, metal particles that are bonded to the resin substrate due to the anchor effect collide with further metal particles, and these are metallurgically bonded together to form a sea of ​​metal material.

[0025] The metal-plated anatase titanium oxide particles in the raw material particles are metallurgically bonded to the metal material through the metal plating on their surfaces, forming a photocatalytic coating in which the anatase titanium oxide particles are dispersed like islands in a sea of ​​metal material.

[0026] The photocatalytic coating preferably has a cross-sectional area percentage of the sea of ​​metal material of more than 50% to 95% or less, more preferably 55 to 90%, and even more preferably 60 to 80%, although this depends on the thickness.

[0027] When the area percentage of the sea of ​​metal particle material is 50 area percent or more, a photocatalytic coating with high adhesion strength can be formed, and when it is 95 area percent or less, the content of anatase-type titanium oxide particles increases, resulting in a high photocatalytic effect. In other words, when the area percentage of metal particles exceeds 95%, the titanium oxide particles decrease and the photocatalytic effect decreases. Also, when it is 50 area percent or less, the metal particles also function as a binder, as described below, and the coating strength may decrease.

[0028] The metal material may be particles of a metal element or an alloy, such as copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), iron (Fe), silver (Ag), titanium (Ti), zinc (Zn), or magnesium (Mg).

[0029] Furthermore, examples of the alloy include alloys containing 50 mass % or more of one metal selected from the group consisting of copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), iron (Fe), silver (Ag), titanium (Ti), zinc (Zn), and magnesium (Mg).

[0030] Among these, copper and silver have a bactericidal effect, so that copper or silver alone or an alloy containing 50% by mass or more of these elements can be preferably used.

[0031] Furthermore, from the viewpoint of design, the use of simple substances such as copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), and silver (Ag) can impart gloss and luster to the photocatalytic coating, while the use of simple substances such as iron (Fe) and titanium (Ti) can form a matte photocatalytic coating.

[0032] Furthermore, by changing the component ratio of the above alloys, for example, Cu--Zn and Cu--Ni--Zn, it is possible not only to improve the hardness and durability of the photocatalytic coating but also to change the color of the photocatalytic coating.

[0033] In addition, by making the surface roughness (Ra) 25 μm or less, the tactile feel can be improved, and if the surface roughness (Ra) is in the range of 5 to 25 μm, a luxurious feel can be created by the grained texture, and by making the surface roughness (Ra) less than 5 μm, the metallic luster can be improved.

[0034] The average particle size of the metal particles is preferably 10 to 50 μm, more preferably 20 to 40 μm. This increases the kinetic energy of the cold spray, improving the efficiency of film formation. Furthermore, when the thickness of the photocatalytic coating is about 100 μm, if the particle size of the metal particles exceeds 50 μm, the metal particles tend to fall off during polishing and grinding. In addition, the larger the metal particles, the less uniformly dispersed the titanium oxide particles are on the surface of the photocatalytic coating.

[0035] As the metal-plated titanium oxide particles, anatase type titanium oxide particles having an average particle size of 0.01 μm to 2 μm and plated with a metal or alloy that can be used for the above metal materials can be used.

[0036] The metal-plated titanium oxide particles can be formed by supporting a palladium (Pd) catalyst on the surface of titanium oxide particles and then electroless plating the particles.

[0037] Furthermore, anatase-type titanium oxide particles carrying copper within the particles exhibit a photocatalytic effect not only with ultraviolet light but also with visible light, and therefore can be preferably used indoors where there is little ultraviolet light, since they can be endowed with self-cleaning properties.

[0038] An example of such titanium oxide particles is TKP-103 manufactured by Teika.

[0039] Since the resin member of the present invention has self-cleaning properties, it can be preferably used for automobile resin parts such as steering wheels and door handles that are prone to adhesion of sebum stains, as well as for transport equipment resin parts, electronic equipment resin parts, home appliance resin parts, office resin parts, housing resin parts, medical and sanitary resin parts, etc.

[0040] <Method for producing a resin member> Next, a method for producing the above-mentioned resin member will be described in detail. The method for producing a resin member of the present invention includes a coating step in which raw material particles containing metal-plated anatase type titanium oxide particles and metal particles are sprayed onto the surface of a resin substrate by a cold spray method to form a photocatalytic coating, and a step in which the surface of the photocatalytic coating formed in the coating step is polished and / or ground to expose the anatase type titanium oxide particles.

[0041] As described above, the cold spray method is a method of forming a coating by using a working gas at about 500 to 600°C, at which the raw material particles do not melt, and by causing the raw material particles in a solid state to collide with a substrate using a supersonic flow of the working gas, while the raw material particles are in an unmolten state without melting or gasifying them.

[0042] According to this cold spray method, metal particles among raw material particles collide at supersonic speed and undergo plastic deformation to form a coating. Therefore, unlike other thermal spraying methods, this method can minimize changes in the properties of the raw material particles due to heat, thereby preventing the titanium oxide particles from transforming from anatase to rutile.

[0043] In a typical cold spray method for forming a coating on a metal substrate, the nozzle spraying the raw material particles is brought close to the metal substrate to prevent a decrease in the temperature and kinetic energy of the raw material particles, causing the raw material particles to collide with the metal substrate.

[0044] In the present invention, since a coating is formed on a resin substrate, the distance between the nozzle for injecting raw material particles and the resin substrate is increased to lower the temperature of the working gas below the heat-resistant temperature of the resin substrate.

[0045] Specifically, the working gas is injected at 500 to 600°C, and the temperature is lowered to 100 to 150°C before the raw material particles collide with the resin substrate. This prevents deformation and deterioration of the resin substrate due to the working gas.

[0046] The working gas expands and its temperature drops when it is sprayed from the nozzle. If the distance between the nozzle and the resin substrate is too close, the temperature of the working gas will not drop sufficiently, causing the resin substrate to melt. Conversely, if the distance is too far, not only will the working gas cool too much, but the speed of the raw material particles will decrease, reducing their adhesion to the resin substrate. Therefore, the distance between the nozzle and the resin substrate is preferably about 150 mm.

[0047] The resin constituting the resin substrate is not particularly limited, and either a thermoplastic resin or a thermosetting resin can be used.

[0048] In particular, when the resin substrate is a thermoplastic resin, the kinetic energy of the raw material particles is converted into thermal energy by the collision, and the thermoplastic resin at the site where the raw material particles collide melts locally and fuses to the colliding raw material particles, which, together with the bonding due to the anchor effect, can improve the bonding strength between the resin substrate and the photocatalytic coating.

[0049] The speed of the raw material particles that can be embedded into the resin substrate by the cold spray method and bonded by the anchor effect is preferably 200 to 500 m / s, although this depends on the hardness of the resin substrate.

[0050] The method for producing a resin member of the present invention includes, after the coating step, a step of polishing and grinding the surface of the formed photocatalytic coating.

[0051] As described above, the titanium oxide particles in the raw material particles have a metal-plated surface. Therefore, by polishing and grinding the surface of the photocatalytic coating, the metal plating is removed, exposing the anatase-type titanium oxide on the surface of the photocatalytic coating, thereby exhibiting the photocatalytic effect.

[0052] Furthermore, by adjusting the surface roughness of the photocatalytic coating by polishing or grinding, it is possible to improve the feel as described above and to impart design features such as gloss, matte finish, and textured finish.

[0053] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0054] Example 1 A palladium (Pd) catalyst was carried on the surface of anatase type titanium oxide particles (JA-1 manufactured by Teika Co., Ltd.), and electroless plating was carried out to obtain anatase type titanium oxide particles having copper-plated surfaces.

[0055] Copper particles (Cu-HWQ-350 manufactured by Fukuda Metal Foil & Powder Co., Ltd.) and the above-mentioned plated anatase-type titanium oxide particles were mixed at a mass ratio of 4:1 to form raw material particles, which were sprayed onto the surface of a polypropylene resin substrate by cold spraying under the following conditions to form a photocatalytic coating. The surface was then ground with a brush to produce a resin part with the structure shown in Figure 1. Cold spray conditions: Apparatus: PCS-1000 (manufactured by Plasma Giken Kogyo Co., Ltd.) Working gas: N ２ Gas, spray pressure 3 MPa, spray temperature 600°C Nozzle-substrate distance: 150 mm (temperature of raw material particles when colliding with resin substrate: 100°C, collision speed of raw material particles: 300 m / s)

[0056] The cross section of the resin member produced in Example 1 was observed using energy dispersive X-ray spectroscopy (SEM-EDX) and elemental analysis of the photocatalytic coating was performed. As a result, it was confirmed that the photocatalytic coating had a sea-island structure in which anatase-type titanium oxide particles were dispersed like islands in a sea of ​​metal material, and that deterioration of the resin substrate by titanium oxide could be prevented.

[0057] REFERENCE SIGNS LIST 1 Resin member 2 Photocatalytic coating 21 Anatase type titanium oxide particles 22 Metal material 3 Resin substrate

Claims

1. A resin member having a photocatalytic coating on the surface of a resin substrate, characterized in that the photocatalytic coating has a sea-island structure in which anatase type titanium oxide particles are dispersed in the form of islands in a sea of ​​metal material.

2. The resin member according to claim 1, characterized in that the surface area percentage of the metal material in the cross section of the photocatalytic coating is more than 50% and not more than 95%.

3. The resin member according to claim 1, characterized in that the metal material has a Vickers hardness of 700 (Hv) or less.

4. The resin member according to claim 1, characterized in that the resin substrate and the photocatalytic film are bonded together at least by an anchor effect.

5. The resin member according to claim 1, characterized in that the surface roughness (Ra) is 25 μm or less.

6. The resin member according to any one of claims 1 to 5, which constitutes a resin part selected from the group consisting of automobile resin parts, transport equipment resin parts, electronic equipment resin parts, home appliance resin parts, office use resin parts, housing resin parts, and medical and sanitary resin parts.

7. A method for producing a resin member according to any one of claims 1 to 5, comprising a coating step of spraying raw material particles in a non-molten state onto the surface of the resin substrate to form a photocatalytic film, the raw material particles including metal-plated anatase type titanium oxide particles, the coating step including a treatment for lowering the temperature of the raw material particles colliding with the resin substrate to 100 to 150°C, and further comprising a step of polishing and / or grinding the surface of the formed photocatalytic film to expose the anatase type titanium oxide particles.

8. The method for producing a resin member according to claim 7, wherein the coating step includes a step of colliding the raw material particles with the resin substrate at a speed of 200 to 500 m / s.

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