JP4931054B2 - Method for producing thin film pigment - Google Patents

Description

  The present invention relates to a method for producing a thin film pigment made of a metal or a metal compound suitable for use in a pigment of a metallic paint, for example.

  In the field of automobile painting and the like, metallic paints using a high reflectance material made of a metal or a metal compound such as aluminum as a pigment are widely used. Conventionally, metal powder produced by an atomizing method or the like has been used. However, in recent years, there has been a demand for higher brightness, and vapor-deposited metal flakes having good surface smoothness have been used (for example, see Patent Document 1 below). ). Patent Document 2 listed below discloses a method for producing a structural color pigment using a laminate obtained by alternately laminating two types of metal oxide films having different refractive indexes as a thin film pigment.

  A typical example of a conventional method for producing a thin film pigment will be described. First, a release layer is formed on a sheet-like substrate such as plastic. Thereafter, an aluminum thin film is formed on the release layer by a vacuum deposition method, and then the aluminum thin film is peeled off from the substrate. Then, after the peeled aluminum thin film is pulverized by a ball mill or the like to obtain a thin piece, only the desired size is classified.

JP 2005-298905 A JP 2005-307237 A

  However, in the conventional method for producing a thin film pigment described above, since the obtained aluminum thin film is crushed into thin pieces, mechanical stress is applied to the aluminum thin pieces, and the surface smoothness of the thin pieces is reduced. There is an inevitable problem. When the surface smoothness of the flakes is lowered, the surface reflectance of the flakes is lowered and the desired metallic luster cannot be obtained.

  In addition, in the conventional method for producing a thin film pigment described above, there is a problem that the shape of the flakes that affect the paintability cannot be controlled because the aluminum thin film is cut into thin pieces by the pulverization process. Furthermore, there is a problem that material loss in the classification process is large, and the manufacturing cost of the metal flakes cannot be reduced.

  This invention is made | formed in view of the above-mentioned problem, and makes it a subject to provide the manufacturing method of the thin film pigment which is excellent in surface smoothness and can perform shape control easily.

  In solving the above problems, the method for producing a thin film pigment of the present invention comprises a step of forming a water-soluble or oil-soluble underlayer having a predetermined pattern shape on a substrate, and a metal or A step of forming a thin film made of a metal compound, a step of immersing the base material in water or oil to dissolve the base layer, and separating and collecting the flakes made of the metal or metal compound from the base material And have.

  In the present invention, only the thin film deposited on the underlayer is selectively separated from the base material (also referred to as a lift-off method), whereby a flake having a shape corresponding to the shape pattern of the underlayer is obtained. Therefore, a thin film pigment having a desired shape can be produced easily and at low cost by arbitrarily setting the pattern shape of the underlayer. Moreover, since the mechanical refinement process such as pulverization is not performed, the surface smoothness of the flakes can be kept high.

  The material constituting the thin film pigment according to the present invention is aluminum (Al), copper (Cu), nickel (Ni), chromium (Cr), iron (Fe), silicon (Si), tantalum (Ta), niobium (Nb). ), Titanium (Ti), zirconium (Zr), magnesium (Mg), silver (Ag), gold (Au), platinum (Pt), palladium (Pd), or the like, or these two types The above alloys are mentioned. Also included are flakes made of metal compounds such as oxides, nitrides or carbides of these metal materials.

  The material constituting the base layer is not particularly limited as long as it is a water-soluble or oil-soluble material, and a resin material, an ink material, or the like can be used. The formation method of the base layer on the substrate is not particularly limited as long as the base layer can be formed in a predetermined pattern shape. For example, printing methods such as relief printing, flexographic printing, and screen printing, ink jet methods, etc. Techniques can be used.

  A method for forming a metal or metal compound thin film on the substrate on which the underlayer is formed is not particularly limited, and various CVD methods can be employed in addition to the vacuum deposition method, the sputtering method, and the ion plating method. Here, productivity can be improved by employing a roll method in which a flexible film is used as a base material and film formation is performed while continuously winding the base material.

  Note that in the same chamber, the surface of the metal film that has been subjected to film formation can be subjected to plasma treatment to modify the surface of the thin film such as corrosion resistance. In addition, a thin film pigment having a structural color utilizing the light interference effect can be obtained by forming the thin film as a laminated film in which two types of metal oxides having different refractive indexes are alternately laminated.

  As described above, according to the method for producing a thin film pigment of the present invention, since the surface smoothness is excellent and the shape can be easily controlled, a thin film pigment having high reflection luminance and no variation in paintability is obtained. It can be manufactured easily and at low cost.

  Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are a schematic diagram and a process flow diagram for explaining a method for producing a thin film pigment according to an embodiment of the present invention. The manufacturing method of the thin film pigment of this embodiment is:
(1) a step of forming a water-soluble or oil-soluble underlayer having a predetermined pattern shape on the substrate; (2) a step of forming a thin film made of a metal or a metal compound on the substrate;
(3) A step of immersing the base material in water or oil to dissolve the base layer, and separating and recovering the flakes made of the metal or metal compound from the base material.

  First, as shown in FIG. 1A, a substrate 1 is prepared. As the base material 1, a flexible plastic film such as a PET (polyethylene terephthalate) film cut to a predetermined width can be used. The substrate 1 is not limited to a plastic film, and the material is not particularly limited as long as it is a material that can be printed on the surface, such as paper or metal foil.

  Next, as shown in FIG. 1B, the base layer 2 is patterned in a predetermined shape on the surface of one side of the substrate 1 (step S1 in FIG. 2). The underlayer 2 is made of a water-soluble or oil-soluble material. Examples of the water-soluble material include PVA (polyvinyl alcohol), and examples of the oil-soluble material include high-resolution printing ink. In the present embodiment, a water-soluble resin such as PVA is used as a constituent material of the base layer 2.

  As will be described later, the underlayer 2 is for controlling the individual shape and size of the metal flakes to be produced, and the shape and size of the underlayer 2 corresponding to the desired shape and size of the metal flakes. Is set. Specifically, as shown in FIG. 3, for example, a rectangular base layer 2 is patterned on the surface of the substrate 1 with a constant interval. Note that the shape is not limited to the illustrated rectangular shape, and may be a circular shape, an elliptical shape, a triangular shape, or other polygonal shapes, or a combination of these shapes.

  In addition, the thickness of the underlayer 2 is not particularly limited, but the metal thin film 3 can be appropriately separated from the base material 1 in a shape corresponding to the pattern shape of the underlayer 2 in a lift-off process of the metal thin film 3 described later. Thickness is required. Specifically, the thickness of the underlayer 2 is 10 μm or less. The thinner the underlayer 2 is, the more fine pattern can be formed.

  In addition, as a formation method of the base layer 2, methods, such as an inkjet method other than printing methods, such as letterpress printing, flexographic printing, and screen printing, can be used, for example. For example, by using a technique such as ink-jet printing or screen printing of an oil-soluble resin, fine patterning of the underlayer becomes possible, and the yield of flakes can be improved.

  Subsequently, as shown in FIG. 1C, a metal thin film 3 is formed on the surface of the base material 1 from above the base layer 2 by vacuum deposition (step S2 in FIG. 2). The metal thin film 3 is formed on the surface of the substrate 1 exposed between the position immediately above the base layer 2 and the formation region of the base layer 2.

  As the evaporation source, various types such as resistance heating, induction heating, electron beam heating, and laser heating can be used. Note that the method for forming the metal thin film 3 is not limited to the vacuum evaporation method, and a sputtering method, an ion plating method, and various CVD methods can be applied.

  The constituent material of the metal thin film 3 is aluminum (Al), copper (Cu), nickel (Ni), chromium (Cr), iron (Fe), silicon (Si), tantalum (Ta), niobium (Nb), titanium ( Ti), zirconium (Zr), magnesium (Mg), silver (Ag), gold (Au), platinum (Pt), palladium (Pd), etc., any single metal, or an alloy of two or more of these Can be mentioned. Also included are metal compounds such as oxides, nitrides or carbides of these metal materials.

The metal oxide can be formed by introducing an oxidizing gas such as oxygen gas into the film formation atmosphere. Specifically, metal oxide films such as Al ₂ O ₃ , SiO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , and TiO ₂ can be produced. In the case of nitride, a metal nitride film such as AlN, CrN, SiN, TaN, TiN, ZrN, etc. can be produced by using nitrogen, a mixed gas of nitrogen and hydrogen, and a nitriding gas such as ammonia. In the case of carbides, metal carbides such as AlC, SiC, TaC, NbC, and TiC can be produced by using a hydrocarbon gas such as methane or acetylene gas.

  In addition, after the metal thin film 3 is formed, if necessary, the surface of the formed metal thin film may be subjected to a plasma treatment to perform a surface modification process for the purpose of improving corrosion resistance. The treatment method can be appropriately set according to the use of the metal flakes to be produced, the constituent material of the metal thin film 3, and the like. For example, when producing aluminum flakes, the surface can be improved in corrosion resistance by oxygen plasma treatment. it can.

  Next, as shown in FIG. 1D, a lift-off process of the metal thin film 3 is performed (step S3 in FIG. 2). In this step, the base material 1 on which the metal thin film 3 is formed is immersed in water, the base layer 2 is dissolved, and the metal thin film 3 formed on the base layer 2 is selectively peeled off from the base material 1. Or separate. Thereby, the metal flakes 3A having a shape corresponding to the pattern shape of the underlayer 2 are formed. The formed metal flakes 3A are then recovered using a sieve or the like (step S4 in FIG. 2).

  As described above, according to this embodiment, the water-soluble base layer 2 is patterned on the base material 1, and only the metal thin film 3 deposited on the base layer 2 in the lift-off process is selectively selected from the base material 1. Since they are separated, a metal flake 3A having a shape corresponding to the shape pattern of the underlayer 2 is obtained. Therefore, the metal flakes (thin film pigment) 3A having a desired shape can be manufactured easily and at low cost by arbitrarily setting the pattern shape of the underlayer 2.

  In addition, when the metal flakes 3A are formed, the surface smoothness of the flakes can be kept high because no mechanical refining process such as grinding of the metal thin film is performed. Thereby, the fall of the surface reflectance of the metal flakes 3A can be prevented, and it can be suitably used as a pigment for metallic paint having high reflection luminance.

FIG. 4 is a schematic configuration diagram of a take-up vacuum deposition apparatus 10 suitable for use in the method for producing a thin film pigment according to the present invention. The vacuum deposition apparatus 10 includes a vacuum chamber 11 that can be evacuated to a predetermined degree of decompression (for example, 10 ⁻³ Pa level). Inside the vacuum chamber 11, an unwinding roller 12 for continuously feeding out the base material 1 made of a plastic film on which the underlayer 2 has been formed in advance, a main roller 13 as a cooling can, and a winding roller 14 are provided. I have. An evaporation source 15 is disposed opposite to the main roller 13, and the evaporation material is heated and evaporated by the electron beam irradiated from the electron beam irradiator 16. Furthermore, in the vacuum vapor deposition apparatus 10 shown in the figure, a plasma forming portion (electrode) 18 for surface-treating the surface of the metal thin film 3 on the substrate 1 with oxygen plasma is provided between the main roller 13 and the winding roller 14. It has been.

  As described above, by forming the metal thin film 3 while continuously winding the base material 1, it is possible to increase the productivity of the metal flakes and reduce the manufacturing cost. In addition, since the plasma forming unit 18 is installed, the metal thin film 3 and the surface oxidation treatment of the metal thin film 3 can be performed consistently in the film forming chamber, thereby greatly improving productivity and manufacturing cost. Can be greatly reduced.

  Note that, depending on the constituent material of the underlayer 2, the film forming surface of the substrate 1 may be disposed between the unwinding roller 12 and the main roller 13, as in the winding type vacuum vapor deposition apparatus 20 schematically illustrated in FIG. 5. It is also possible to arrange a base layer forming unit 17 for patterning the base layer 2. As a result, the formation of the underlayer 2, the formation of the metal thin film 3, and the surface oxidation treatment of the metal thin film 3 can be performed in the same chamber.

Further, the film forming apparatus 30 schematically shown in FIG. 6 includes a rotary drum 32 and first and second sputter cathodes 33 </ b> A and 33 </ b> B installed in a vacuum chamber 31. Two types of sputtered films are alternately formed on the substrate 1 while supporting and rotating the substrate 1. For example, titanium is sputtered by the first sputter cathode 33A, silicon is sputtered by the second sputter cathode 33B, and a gas introduction pipe 36 for introducing oxygen gas into the vacuum chamber 31 is installed, thereby providing a base material. TiO ₂ films and SiO ₂ films can be alternately stacked on the substrate 1. These metal oxides have different refractive indexes (TiO ₂ : 2.35, SiO ₂ : 1.46), and have a structural color in a specific wavelength region by appropriately setting the film thickness and the number of layers. A thin film can be formed. In FIG. 6, reference numerals 34 </ b> A and 34 </ b> B are shutters disposed between the sputtering cathodes 33 </ b> A and 33 </ b> B and the rotary drum 32.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

  A PET film having a length of 300 m, a width of 0.2 m, and a thickness of 12 μm wound around a roll was used as a substrate, and a resin-made relief printing was used as a base layer with a polyvinyl alcohol (PVA) solution, which is a water-soluble resin. After applying a pattern with a roll coater, it was dried. As shown in FIG. 3, the pattern shape of the underlayer was a rectangular shape having a length of 50 μm and a width of 80 μm separated at intervals of 30 μm.

  The base material on which the underlayer was formed was placed in a roll-up film forming apparatus “EWS-020” manufactured by ULVAC, Inc., and aluminum was evaporated by electron beam heating to form an aluminum vapor deposition film having a thickness of 0.1 μm. Subsequently, the surface of the aluminum thin film was subjected to plasma oxidation in the film forming chamber to perform corrosion resistance treatment of the thin film.

  The base material on which the aluminum thin film was formed was taken out into the atmosphere, immersed in warm water of about 40 ° C. for 30 minutes to separate the aluminum flakes from the base material, and then recovered using a mesh (sieving). As a result, a rectangular metal flake having a length of 50 μm and a width of 80 μm was obtained.

  As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to this, A various deformation | transformation is possible based on the technical idea of this invention.

  For example, in the above embodiment, the example in which the present invention is applied to the production of a pigment for a metallic paint has been described. However, the present invention is not limited to this, and the present invention can be applied to the production of metal flakes or metal flakes for other uses. .

  In the above embodiment, PVA is used as the constituent material of the underlayer 2, but other than this, for example, a water-soluble starch material or a saccharide material can also be used as the constituent material of the underlayer. is there. Alternatively, an organic resist material may be used as the constituent material of the underlayer 2 and dissolved in an alkaline aqueous solution.

  In addition, it is necessary to select the constituent material of the base layer 2 in consideration of resistance to the solvent of the metal foil piece to be manufactured. For example, when producing a magnesium flake, it is preferable to use an oil-soluble material such as ink for the underlayer because magnesium reacts with water. On the other hand, when obtaining a metal foil piece of magnesium alloy or magnesium oxide, a water-soluble material can be used.

  Further, in the above-described embodiment, the base material 1 after the metal flakes 3A are collected may be reused for the production of the metal flakes, thereby further reducing the manufacturing cost of the metal flakes. Is possible.

It is a schematic diagram which shows each process for demonstrating the manufacturing method of the thin film pigment by embodiment of this invention. It is a process flow figure for explaining a manufacturing method of a thin film pigment by an embodiment of the present invention. It is a top view of the base material which shows an example of the pattern shape of a base layer. It is a schematic block diagram of the winding-type vacuum evaporation apparatus for enforcing the manufacturing method of the thin film pigment which concerns on this invention. It is a schematic block diagram of the winding type vacuum evaporation system which shows the modification of FIG. It is a schematic block diagram of the other film-forming apparatus for enforcing the manufacturing method of the thin film pigment concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Underlayer 3 Metal thin film 3A Metal flake (thin film pigment)
DESCRIPTION OF SYMBOLS 10,20 Winding type vacuum evaporation apparatus 11 Vacuum tank 12 Unwinding roller 13 Main roller 14 Winding roller 15 Evaporation source 16 Electron beam irradiator 17 Underlayer forming unit 18 Plasma forming part 30 Film forming apparatus 31 Vacuum tank 33A, 33B Sputter cathode

Claims (6)

Forming a water-soluble or oil-soluble underlayer having a predetermined pattern shape on a substrate; and
Forming a thin film comprising a metal or a metal compound on the substrate;
A step of dissolving the base layer by immersing the base material in water or oil, and separating and recovering the flakes made of the metal or metal compound from the base material. Method.   The metal is any one of aluminum, copper, nickel, chromium, iron, silicon, tantalum, niobium, titanium, zirconium, magnesium, silver, gold, platinum and palladium, or two or more of these metals It is an alloy, The manufacturing method of the thin film pigment of Claim 1 characterized by the above-mentioned.   The metal compound may be any one kind of metal selected from aluminum, copper, nickel, chromium, iron, silicon, tantalum, niobium, titanium, zirconium, magnesium, silver, or an oxide or nitride of two or more kinds of these metals. The method for producing a thin film pigment according to claim 1, wherein the thin film pigment is a product.   2. The method for producing a thin film pigment according to claim 1, wherein the thin film is a laminated film in which two kinds of metal oxides having different refractive indexes are alternately laminated.   The method for producing a thin film pigment according to claim 1, wherein the base material is made of a flexible film, and the thin film is formed while the base material is continuously wound up. The method for producing a thin film pigment according to claim 1, further comprising a step of performing a plasma treatment on a surface of the thin film after the film forming step of the thin film.

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