Resin member

Abstract

A resin member according to the present invention is such that a photocatalytic coating film is provided on the surface of a resin substrate.　The photocatalytic coating film includes anatase type titanium oxide particles and metal particles. By stacking the metal particles so as to shield the resin substrate and dispersing the anatase type titanium oxide particles among the metal particles, it is possible to provide a resin member that is provided with a photocatalytic coating film and that has a high photocatalytic effect and prevents deterioration of the resin substrate.

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 present inventors have found that the above-mentioned object can be achieved by spraying anatase type titanium oxide particles and metal particles in a non-molten state onto a resin substrate by a cold spray method, and shielding the resin substrate with the metal particles, thereby completing the present invention.

[0009] That is, the resin workpiece of the present invention comprises a photocatalytic coating on the surface of a resin substrate, and the photocatalytic coating contains anatase-type titanium oxide particles and metal particles, the metal particles being stacked to shield the resin substrate, and the anatase-type titanium oxide particles being dispersed among the metal particles.

[0010] The method for producing a resin member of the present invention is a method for producing the resin member of the present invention, and includes a coating step of spraying raw material particles in a non-molten state onto the surface of the resin substrate to form a photocatalytic coating, wherein the raw material particles include anatase type titanium oxide particles and metal particles, and the coating step includes a treatment of lowering the temperature of the raw material particles colliding with the resin substrate to 100 to 150°C.

[0011] According to the present invention, anatase type titanium oxide particles and metal particles are sprayed onto a resin substrate in a non-molten state, and the resin substrate is shielded by the metal particles. This makes 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; FIG. 2 is a diagram showing an example of granulated raw material particles; and FIG. 3 is a cross-sectional image 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 a photocatalytic coating on the surface of a resin substrate, and as shown in Figure 1, this photocatalytic coating comprises stacked metal particles shielding the resin substrate, with anatase titanium oxide particles dispersed between the stacked metal particles.

[0014] In the present invention, the phrase "metal particles shield the resin substrate" means that metal particles are present on the optical path of light incident on the resin member from all directions, and titanium oxide that transmits light does not extend from the surface to the interface between the photocatalytic coating and the resin substrate, preventing the light from reaching the resin substrate.

[0015] In other words, even if there are areas at a certain depth in the photocatalytic coating where the metal particles are discontinuous in the in-plane direction, it is sufficient that metal particles are present in the out-of-plane direction (at a different depth) at that area and block the light, and this does not mean that the metal particles form a continuous layer in the in-plane direction at a certain depth.

[0016] Because the metal particles shield the resin substrate in this way, even if titanium oxide particles are present near the interface between the photocatalytic coating and the resin substrate, the titanium oxide near this interface does not exhibit an oxidizing effect, thereby preventing deterioration of the resin substrate.

[0017] Furthermore, the photocatalytic coating on the resin member of the present invention is formed by stacking metal particles, and therefore, unlike plating films with dispersed titanium oxide, even if peeling occurs, the photocatalytic coating does not form edges, so there is no risk of injury even when used in areas that may come into contact with hands, etc.

[0018] The photocatalytic coating can be formed by cold spraying, which is a method of forming a coating by colliding raw material particles in a solid state 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 photocatalytic coating preferably has a cross-sectional area percentage of metal particles of more than 50% to 95% or less, more preferably 55 to 90%, and even more preferably 60 to 80%, although this varies depending on the thickness.

[0021] By keeping the area percentage of the metal particles within the above range, it is possible to prevent light from passing through to the vicinity of the resin substrate and to obtain the photocatalytic effect of the titanium oxide particles near the surface. If the area percentage of the metal particles exceeds 95%, the titanium oxide particles are reduced, resulting in a decrease in the photocatalytic effect. Furthermore, if the area percentage is 50% or less, the metal particles also function as a binder, as described below, and the coating strength may decrease.

[0022] The metal material constituting the metal particles may be a single metal or an alloy.

[0023] The metal material has ductility and malleability and is capable of plastic deformation. The metal particles of the present invention not only shield the resin substrate from incident light, but also serve as a binder that holds the titanium oxide particles and forms a photocatalytic coating with high adhesive strength.

[0024] 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.

[0025] When the metal particles are made of a metal material having a Vickers hardness of 700 (Hv) or less, the metal particles undergo significant plastic deformation due to collisions during coating formation by the cold spray method.

[0026] This plastic deformation of the metal particles results in high adhesion and bonding strength, improving the strength of the coating, and also allows the titanium oxide particles to be held without plastic deformation, thereby improving the efficiency of coating formation.

[0027] In other words, the metal particles sprayed onto the resin substrate by cold spraying sink into the resin substrate, undergo plastic deformation, and adhere tightly, forming irregular irregularities at the interface with the resin substrate, which bond to the resin substrate through an anchor effect. Furthermore, these metal particles catch and hold titanium oxide particles that collide with them later, preventing them from bouncing off.

[0028] In this way, with the coating formation method in which raw material particles containing metal particles are cold sprayed, the metal particles undergo plastic deformation upon collision and are metallurgically bonded together, and the titanium oxide particles are mechanically bonded to the metal particles and resin substrate by the anchor effect, rather than by metallurgical bonding such as the formation or diffusion of intermetallic compounds.

[0029] There is no particular lower limit for the Vickers hardness of the metal material, but it has been confirmed that a film can be formed even with metal particles having a Vickers hardness of 350 (Hv).

[0030] Examples of the metal element include copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), iron (Fe), silver (Ag), titanium (Ti), zinc (Zn), and magnesium (Mg).

[0031] 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).

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The color of the photocatalytic coating can also be changed by forming a colored layer on the surface of the metal particles. Examples of the colored layer include a plating film, a chemical conversion film, and an inorganic pigment coating film.

[0036] Examples of the plating film include nickel (Ni), nickel-phosphorus (Ni-P), copper (Cu), and zinc (Zn), and these plating films can be formed by electroless plating.

[0037] Examples of the chemical conversion film include phosphate films such as zinc phosphate films, iron phosphate films, and manganese phosphate films formed by phosphate film treatment, chromium oxide films formed by chromate treatment, and triiron tetroxide films formed by black oxide treatment.

[0038] The inorganic pigment coating film can be formed by embedding the inorganic pigment into the surface of metal particles using a high-speed airflow impact method or by spray coating using molten glass as a binder. Examples of the inorganic pigment include natural mineral pigments obtained from minerals or soil, as well as synthetic inorganic pigments such as metal oxides.

[0039] The resin member of the present invention may further have a plating film having defects on the photocatalytic coating, which allows the color of the surface of the resin member to be different from that of the photocatalytic coating, and also allows the anatase titanium oxide particles of the photocatalytic coating to be exposed through the defects in the plating film, thereby enabling the photocatalytic effect to be exerted.

[0040] The plating film having the above defects can be produced by connecting the photocatalytic coating to a DC power supply and forming the plating film in a treatment solution.

[0041] In such electrolytic plating methods using a DC power source, anatase-type titanium oxide particles are not electrically conductive, so a plating film is not formed on the anatase-type titanium oxide particles exposed on the surface of the photocatalytic coating, and a plating film is formed only on the portions of the photocatalytic coating surface that are formed by metal particles, making it possible to expose the anatase-type titanium oxide particles from defective portions of the plating film.

[0042] Examples of the plating film formed on the photocatalytic coating include plating films of metals that can be electroplated, such as copper, nickel, chromium, gold, silver, and zinc.

[0043] Furthermore, the resin member of the present invention can improve its tactile feel by having a surface roughness (Ra) of 25 μm or less. A surface roughness (Ra) in the range of 5 to 25 μm can create a luxurious feel due to the grained texture, and a surface roughness (Ra) of less than 5 μm can improve metallic luster.

[0044] The average particle size of the metal particles is preferably 10 to 50 μm, more preferably 20 to 40 μm. This improves shielding properties and increases the kinetic energy of the metal particles during cold spraying, improving the efficiency of film formation. Furthermore, when the thickness of the photocatalytic coating is approximately 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.

[0045] As the titanium oxide particles, anatase type titanium oxide particles having an average particle size of 0.01 μm to 2 μm can be used.

[0046] 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 imparted with self-cleaning properties.

[0047] An example of such titanium oxide particles is TKP-103 manufactured by Teika.

[0048] 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.

[0049] <Method for producing a resin member> Next, a method for producing the resin member of the present invention will be described in detail. The method for producing a resin member of the present invention includes a coating step of spraying raw material particles containing anatase titanium oxide particles and metal particles onto the surface of a resin substrate by a cold spray method to form a photocatalytic coating.

[0050] As described above, the cold spray method is a method of forming a coating by causing solid-phase raw material particles to collide with a substrate using a supersonic flow of a working gas while the raw material particles are in an unmolten state, without melting or gasifying them.

[0051] With cold spraying, metal particles in raw material particles collide at supersonic speed and undergo plastic deformation to form a coating. This means that, unlike other thermal spraying methods, it is possible to minimize changes in the properties of the raw material particles due to heat and oxidation in the coating, thereby preventing the titanium oxide particles from transforming from anatase to rutile.

[0052] Furthermore, the cold spray method uses a working gas at about 500 to 600° C., which does not melt the raw material particles.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The resin constituting the resin substrate is not particularly limited, and either a thermoplastic resin or a thermosetting resin can be used.

[0058] 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.

[0059] 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.

[0060] The raw material particles may be a mixture of anatase type titanium oxide particles and metal particles, but are preferably granulated particles formed by bonding anatase type titanium oxide particles and metal particles together to form large particles.

[0061] As described above, the titanium oxide particles are fine powders with an average particle size of 0.01 μm to 2 μm, and therefore tend to agglomerate, making them difficult to transport and likely to cause nozzle clogging.

[0062] By using the large-sized granulated particles as the raw material particles, clogging of the nozzle can be prevented, and the kinetic energy of the raw material particles is increased, improving the efficiency of forming the photocatalytic film.

[0063] The form of the granulated particles is not particularly limited, and may be, as shown in FIG. 2, a metal particle as a core around which the anatase type titanium oxide particles are attached, or conversely, an anatase type titanium oxide particle as a core around which the metal particles are attached, or a mixture of anatase type titanium oxide particles and metal particles.

[0064] The method for producing a resin member of the present invention may further include, after the coating step, a step of polishing or grinding the surface of the formed photocatalytic coating.

[0065] As mentioned above, titanium oxide particles have a smaller particle size than metal particles and are therefore more likely to be exposed on the surface of the photocatalytic coating. However, by polishing or grinding the surface of the photocatalytic coating, the anatase type titanium oxide is uniformly exposed, thereby achieving a uniform photocatalytic effect.

[0066] Furthermore, by adjusting the surface roughness of the photocatalytic coating by polishing or grinding, it is possible to impart design features such as gloss, matte finish, and textured finish, which improve the feel of the surface, as described above.

[0067] 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.

[0068] Example 1 A mixture of copper particles (Cu-HWQ-350 manufactured by Fukuda Metal Foil & Powder Co., Ltd.) and anatase-type titanium oxide particles (JA-1 manufactured by Teika Co., Ltd.) at a mass ratio of 6:1 was sprayed onto the surface of a polypropylene resin substrate by cold spraying under the following conditions to form a photocatalytic coating, and the surface was then ground with a brush to produce a resin part. 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)

[0069] The cross section of the resin member was observed by energy dispersive X-ray spectroscopy (SEM-EDX) and the photocatalytic film was subjected to elemental analysis. The analysis results are shown in Figure 3.

[0070] From FIG. 3, it can be seen that there is no portion where titanium (Ti) is continuous from the surface to the resin substrate, and the resin substrate is shielded by copper (Cu) particles, thereby preventing deterioration of the resin substrate due to titanium oxide.

[0071] REFERENCE SIGNS LIST 1 Resin member 2 Photocatalytic coating 21 Anatase type titanium oxide particles 22 Metal particles 3 Resin substrate

Claims

1. A resin component having a photocatalytic coating on the surface of a resin substrate, The above photocatalytic coating contains anatase-type titanium dioxide particles with an average particle size of 0.01 μm to 2 μm and metal particles with an average particle size of 10 to 50 μm. A resin member characterized in that the anatase-type titanium oxide particles are dispersed between the metal particles, and the metal particles are stacked on top of each other, shielding the resin substrate from the anatase-type titanium oxide particles.

2. The resin member according to claim 1, characterized in that the photocatalytic coating has a cross-sectional area percentage of metal particles that is greater than 50% and less than or equal to 95%.

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

4. The resin member according to claim 1, characterized in that the resin substrate and the photocatalytic coating are joined by at least an anchoring 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 claim 1, characterized in that the above-mentioned metal particles have a colored layer on their surface.

7. The resin member according to claim 6, characterized in that the above-mentioned colored layer is a plating film selected from the group consisting of nickel (Ni), nickel-phosphorus (Ni-P), copper (Cu), and zinc (Zn).

8. The resin member according to claim 6, characterized in that the above-mentioned colored layer is a chemical conversion film selected from the group consisting of a phosphate film, a chromium oxide film, and a triiron tetroxide film.

9. The resin member according to claim 6, characterized in that the above-mentioned colored layer is an inorganic pigment coating film containing an inorganic pigment.

10. Furthermore, the photocatalytic coating has a defective plating film, The resin member according to claim 1, characterized in that the anatase-type titanium oxide particles of the photocatalytic coating are exposed due to defects in the plating film.

11. A resin component according to any one of claims 1 to 10, characterized in that it comprises a resin component selected from the group consisting of automotive resin components, transportation equipment resin components, electronic equipment resin components, home appliance resin components, office resin components, housing resin components, and medical and hygiene resin components.

12. A method for manufacturing a resin member according to any one of the above claims 1 to 11, The process includes a coating step in which non-molten raw material particles are sprayed onto the surface of the resin substrate to form a photocatalytic coating, The above raw material particles include anatase-type titanium dioxide particles and metal particles. A method for manufacturing a resin member, characterized in that the coating step includes a process to reduce the temperature of the raw material particles that collide with the resin substrate to 100 to 150°C.

13. The method for manufacturing a resin member according to claim 12, characterized in that the coating step includes a procedure in which the raw material particles are impacted onto the resin substrate at a speed of 200 to 500 m / s.

14. The method for manufacturing a resin member according to claim 12, further comprising a step of polishing and / or grinding the surface after the coating step described above.

15. The method for producing a resin member according to claim 12, characterized in that the raw material particles are granulated particles of anatase-type titanium oxide particles and metal particles.

16. The method for manufacturing a resin member according to claim 15, characterized in that the granulated particles have the metal particles as a core and the anatase-type titanium oxide particles attached around it.

17. The method for manufacturing a resin member according to claim 15, characterized in that the granulated particles have the anatase-type titanium oxide particles as a core, with the metal particles attached around them.

18. The method for producing a resin member according to claim 15, characterized in that the granulated particles are particles in which anatase-type titanium oxide particles and metal particles are mixed.