JP2012140479A - Composition for forming reflective coat and reflective substrate using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition useful for forming a reflective coat excellent in reflectivity.SOLUTION: This composition is composed of a white pigment (e.g. titanium oxide, zirconium oxide, aluminum oxide and others), glass containing at least zinc borosilicate glass, and a resin. In such the composition, the proportion of the white pigment and the glass is around the former/the latter (weight ratio)=95/5 to 5/95, and the proportion of the resin may be around 3-70 pts.wt. based on 100 pts.wt. of the total of the white pigment and the glass.

Description

  The present invention relates to a composition useful for forming a reflective film and the like, a method for producing a reflective substrate using this composition, and a reflective substrate obtained by this method.

  A light emitting diode (LED) element is widely used in various lighting devices and display devices as a light source with low power consumption and long life. Since such an LED element has a characteristic that its luminance is reduced by self-heating, it is necessary to increase the heat dissipation of the substrate on which the element is mounted and to reduce the temperature of the element.

  For this reason, although aluminum nitride excellent in thermal conductivity is used as the substrate material of the LED element, since aluminum nitride is a light-transmitting material, there is a problem that light of the LED element leaks through the substrate. Therefore, if a reflective film that reflects visible light can be formed on the surface of the aluminum nitride substrate, light leakage through the substrate can be prevented and luminous efficiency can be improved while utilizing the high thermal conductivity of aluminum nitride.

For example, in Japanese Unexamined Patent Publication No. 2009-212134 (Patent Document 1), in an aluminum nitride package provided with a recess, the surface inside the recess is selected from TiO ₂ , Al ₂ O ₃ , MgO, and SiO _2. An aluminum nitride package in which a reflective layer made of one or more inorganic pigments and a cured binder is formed is disclosed. And in the Example of this literature, ethylcellulose is used as binder hardened | cured material.

  On the other hand, gold-tin solder having high thermal conductivity is used as a bonding material between the LED element and the electrode on the surface of the aluminum nitride substrate. However, since the melting point of gold-tin solder is as high as 280 ° C., the bonding between the LED element and the electrode when using it requires heating to 300 ° C. or higher, and sometimes 400 ° C. The film is also required to have heat resistance to withstand heating at 300 to 400 ° C.

  However, although the reflective layer containing a binder like patent document 1 can be manufactured easily, there is a possibility that the binder is discolored by heating and the reflectivity is lowered, so that it does not function as a reflective substrate.

JP 2009-212134 A (claims, paragraphs [0024], [0028], [0063])

  An object of the present invention is to provide a composition useful for forming a reflective film having excellent reflectivity, a method for producing a reflective substrate using the composition, and a reflective substrate obtained by this method. is there.

  Another object of the present invention is to provide a composition capable of forming a reflective film capable of achieving both high strength and high reflectivity, a method for producing a reflective substrate using this composition, and a reflective substrate obtained by this method. There is to do.

  Still another object of the present invention is to provide a composition capable of forming a reflective film having excellent heat resistance, a method for producing a reflective substrate using this composition, and a reflective substrate obtained by this method.

  The present inventors tried to combine resin and glass as a binder. Here, when glass is used as the binder, the glass is melted in a non-oxidizing atmosphere (for example, an inert gas) in consideration of suppressing oxidation of an electrode (for example, a copper electrode) provided on the substrate. However, in such a non-oxidizing atmosphere, the decomposition residue of the resin may remain in the reflective film even when heated at a high temperature. The reflectivity could not be improved.

  In such a situation, as a result of intensive studies to achieve the above-mentioned problems, the present inventors have combined a white pigment, glass and resin, further containing zinc borosilicate glass in the glass, By sintering such a composition (high-temperature heat treatment), the decomposition of the resin (and also the solvent in the paste-like composition) is promoted as the glass melts even in a non-oxidizing atmosphere. In addition to being excellent in reflectivity, a high-strength film can be obtained by sintering. Further, the film obtained by such a method is formed of a sintered body of white pigment and glass, and is subjected to high temperature conditions. The present invention was completed by discovering that the film is excellent in heat resistance and does not impair reflectivity even when exposed underneath.

  That is, the composition of the present invention is a composition containing a white pigment, glass, and a resin, and the glass contains zinc borosilicate glass.

  The white pigment may contain at least one selected from, for example, a titanium compound, a zirconium compound, and an aluminum compound. The white pigment may be particles having an average particle diameter (D50) of 0.05 to 20 μm.

  The glass may contain, for example, zinc borosilicate glass containing 10% by weight or more of zinc (or zinc component) in terms of ZnO.

  In the composition, the ratio between the white pigment and the glass may be, for example, the former / the latter (weight ratio) = about 95/5 to 5/95, and the ratio of the resin is, for example, between the white pigment and the glass About 3-70 weight part may be sufficient with respect to 100 weight part of total amounts.

  In a typical composition of the present invention, the white pigment is a particle having an average particle diameter (D50) of 0.1 to 10 μm containing at least one selected from titanium oxide, zirconium oxide, and aluminum oxide, and glass. Includes zinc borosilicate glass containing 15 to 75% by weight of zinc in terms of ZnO, the ratio of white pigment to glass is the former / the latter (weight ratio) = 80/20 to 20/80, and the ratio of the resin is The composition etc. which are 10-50 weight part with respect to 100 weight part of total amounts of a white pigment and glass are contained.

  In the composition of the present invention, the proportion of zinc may be about 5 to 300 parts by weight in terms of ZnO with respect to 100 parts by weight of the resin. Further, the composition of the present invention may be a paste composition further containing a solvent.

  Such a composition of the present invention may be a reflective film forming composition for forming a reflective film on a substrate (for example, an aluminum nitride substrate).

  The present invention also includes a method for manufacturing a reflective substrate in which a film is formed on a substrate (for example, an aluminum nitride substrate) with the composition and then fired. That is, a sintered film of the composition is formed on the substrate (on the substrate) by the firing treatment. In such a method, typically, an aluminum nitride substrate may be used and fired at 600 ° C. or higher in a non-oxidizing atmosphere.

  The present invention also includes a reflective substrate obtained by the above method.

  The composition of the present invention is useful for forming a reflective film having excellent reflectivity. In particular, since the composition of the present invention combines a resin and glass as a binder in a reflective film, both high strength and high reflectivity can be achieved even by sintering treatment in an inert gas. . Moreover, in the composition of this invention, since a reflective film can be formed with a white pigment and glass by sintering, the reflective film excellent in heat resistance can be formed. For this reason, even after the reflective film is formed, even if the reflective film is subjected to conditions under which high temperature acts, the excellent reflectivity (and high strength) of the reflective film can be maintained.

FIG. 1 is a graph showing the reflectance (before heat treatment) in the visible light region of the solid pattern obtained in Example 2, the solid pattern obtained in Example 7, and the aluminum nitride substrate.

[Composition]
The composition of the present invention includes a white pigment, glass, and a resin.

(White pigment)
As the white pigment, an organic pigment may be used, but usually an inorganic pigment can be preferably used. The white pigment may be a composite white pigment or may contain an extender pigment. Examples of such white pigments include alkali or alkaline earth metal compounds [eg, magnesium compounds (eg, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium sulfate), calcium compounds (eg, calcium carbonate, calcium sulfate]). , Calcium phosphate, etc.), barium compounds (eg, barium sulfate, etc.)], transition metal compounds {eg, periodic table Group 3 metal compounds [eg, cerium compounds (eg, cerium oxide, etc.)], periodic table Group 4 metals Compound {for example, titanium compound [for example, titanium oxide (titanium dioxide), titanate (for example, alkali metal titanate such as potassium titanate; magnesium titanate, calcium titanate, strontium titanate, barium titanate, etc. Titanic acid Metal titanates such as Lucari earth metal salts), titanium phosphates, etc.], zirconium compounds (eg, zirconium oxide, etc.)}, periodic table Group 12 metal compounds [eg, zinc compounds (eg, zinc oxide, sulfides) Zinc, lithopone, etc.)], etc.], periodic table group 13 metal compounds {eg, aluminum compounds [eg, aluminum oxide (alumina white), aluminum hydroxide, etc.]}, periodic table group 14 metal compounds [eg, Lead compounds (for example, lead white), etc., Periodic Table Group 15 compounds [for example, antimony compounds (for example, antimony oxide), etc.], other white pigments (for example, extender pigments) [for example, boron compounds (for example, boron nitride, etc.) ), Silicates (eg, magnesium silicate, calcium silicate, barium silicate, aluminum silicate, Magnesium aluminum), mineral acids (talc, kaolin, clay, zeolite, etc. bentonite, etc.), etc.]. The crystal structure of titanium oxide may be any of rutile type, anatase type, brookite type, etc., and from the viewpoint of whiteness (hiding degree), titanium oxide having a rutile type structure is preferably used. Also good.

  White pigments may be used alone or in combination of two or more.

  Typical white pigments include a Group 4 metal compound of the periodic table [for example, a titanium compound (for example, titanium oxide, titanate), a zirconium compound (such as zirconium oxide)], a periodic table, because of its excellent whiteness. Group 13 metal compounds [for example, aluminum compounds (such as aluminum oxide)] and the like are included. Therefore, the white pigment includes at least these compounds [for example, at least one selected from titanium compounds (particularly titanium oxide), zirconium compounds (particularly zirconium oxide), and aluminum compounds (particularly aluminum oxide)). You may go out.

  Therefore, the white pigment may be composed of at least these compounds, and the white pigment may be composed of only these compounds, or may be combined with other white pigments (such as extender pigments). When combined with another white pigment, the ratio of the other white pigment to the whole white pigment is, for example, 50% by weight or less (for example, 0.1 to 40% by weight), preferably 30% by weight or less (for example, 0 0.2 to 20% by weight), more preferably 10% by weight or less (for example, 0.5 to 8% by weight).

  The refractive index (25 ° C.) of the white pigment is, for example, 1.7 or more (for example, 1.8 to 4), preferably 1.9 or more (for example, 2 to 3.5), more preferably 2.1 or more. (For example, 2.1 to 3), particularly about 2.2 or more (for example, 2.3 to 2.9).

  In addition, in order to improve the dispersibility with respect to resin or glass, you may use the white pigment surface-treated (for example, surface treatment by a metal oxide, a coupling agent, etc.) as needed.

  The purity of the white pigment is preferably high from the viewpoint of whiteness. The purity of such a white pigment depends on the type of white pigment, but is generally 80% by weight or more (for example, 83 to 100% by weight), preferably 85% by weight or more (for example, 87 to 100% by weight), More preferably, it may be 88% by weight or more (for example, 90 to 100% by weight). As the purity of a typical white pigment, the purity of titanium oxide is, for example, 85% by weight or more [for example, about 87 to 100% by weight, preferably about 88% by weight or more (for example, about 90 to 100% by weight)], aluminum oxide The purity of, for example, 90% by weight or more [for example, 95 to 100% by weight, preferably 98% by weight or more (for example, 99 to 100% by weight), more preferably 99.5% by weight or more (for example, 99.7%). About 100% by weight).

  The form (or shape) of the white pigment is not particularly limited and may be fibrous, particulate, or the like, but a particulate white pigment may be suitably used. In the particulate white pigment (white pigment particles), the average particle diameter (D50) may be, for example, 0.01 to 50 μm, preferably 0.05 to 20 μm, and more preferably about 0.1 to 10 μm. . By adjusting the particle size to such a range, the gap between the particles can be reduced, and the concentration of the white pigment can be easily increased by suppressing an excessive increase in the viscosity of the composition. Can be improved.

(Glass)
The glass includes at least zinc borosilicate glass. The zinc borosilicate glass is a glass containing at least boron (B ₂ O ₃ ), silicon (SiO ₂ ), and zinc (ZnO). In the borosilicate glass, the ratio of boron may be, for example, 5 to 50% by weight, preferably 7 to 40% by weight, and more preferably about 10 to 30% by weight in terms of B ₂ O ₃ . In the glass containing boron, the ratio of silicon may be, for example, 5 to 50% by weight, preferably 7 to 40% by weight, and more preferably about 10 to 35% by weight in terms of SiO ₂ .

  And in zinc borosilicate glass, the ratio of zinc is 7-85 weight% (for example, 10-80 weight%), for example, preferably 12-75 weight% (for example, 15-75 weight%) in conversion of ZnO. More preferably, it may be about 18 to 72% by weight (for example, 20 to 70% by weight), and usually 10% by weight or more [for example, about 10 to 85% by weight (for example, about 15 to 80% by weight)]. There may be.

In addition, zinc borosilicate glass includes metal oxide [for example, alkali metal oxide (for example, Li ₂ O, Na ₂ O) in addition to boron (B ₂ O ₃ ), silicon (SiO ₂ ), and zinc (ZnO). , K ₂ O, etc.), alkaline earth metals (eg, MgO, CaO, SrO, BaO, etc.), transition metal oxides (eg, MnO ₂ , ZnO), periodic table group 13 metal oxides (eg, Al _2). O ₃ ), periodic table group 14 metal oxides (eg, PbO, Pb ₂ O ₅ ), periodic table group 15 metal oxides (eg, Sb ₂ O ₃ , Bi ₂ O ₃ ), etc.] Also good.

In the zinc borosilicate glass, the ratio of the total amount of boron, silicon and zinc is 50% by weight or more (for example, 60 to 100% by weight), preferably 70% by weight in terms of B ₂ O ₃ , SiO ₂ and ZnO. It may be more (for example, 75 to 99.9% by weight), more preferably 80% by weight or more (for example, 85 to 99% by weight).

The glass may be composed only of zinc borosilicate glass or may contain other glass. Other glass is not particularly limited, for example, soda lime glass, glass containing boron (B ₂ O ₃ ) other than zinc borosilicate glass (for example, borosilicate glass, lead borosilicate glass, borosilicate barium glass, Strontium borosilicate glass, potassium borosilicate glass, aluminoborosilicate glass, bismuth borosilicate glass, etc.), lead glass, aluminosilicate glass, phosphate glass, quartz glass and the like. Other glasses may be used alone or in combination of two or more.

  When the glass contains other glass, the proportion of the zinc borosilicate glass is, for example, 40% by weight or more (for example, 50 to 99.5% by weight), preferably depending on the zinc content of the zinc borosilicate glass. May be 60% by weight or more (for example, 65 to 99% by weight), more preferably 70% by weight or more (for example, 75 to 95% by weight). In addition, when glass contains other glass, the ratio of the zinc component with respect to the whole glass (zinc component derived from zinc borosilicate glass) is, for example, 5 to 85% by weight, preferably 8 to 80% by weight in terms of ZnO. More preferably, it may be about 10 to 75% by weight (for example, 15 to 70% by weight).

  In addition, although the shape (or form) of glass is not specifically limited, Usually, a particle form (frit shape) may be sufficient. In the particulate glass (glass particles, glass frit), the average particle diameter (D50) may be, for example, about 0.1 to 50 μm, preferably about 0.5 to 20 μm, and more preferably about 1 to 10 μm.

(resin)
Although it does not specifically limit as resin, For example, a thermoplastic resin etc. are mentioned. Typical resins include, for example, styrene resins [for example, copolymers of styrene and (meth) acrylic monomers such as polystyrene and styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymers, etc. ] (Meth) acrylic resin {for example, poly (meth) acrylic acid ester (for example, polymethyl methacrylate, polybutyl (meth) acrylate, polyisobutyl methacrylate, etc.), methyl methacrylate- (meth) acrylic acid copolymer, (Meth) acrylic monomers such as methyl methacrylate-acrylic acid ester copolymer and poly (meth) acrylamide [e.g., (meth) acrylic acid; alkyl (meth) acrylate (e.g., methyl (meth) acrylate) , Ethyl (meth) acrylate, butyl (meth) acrylate, (me ), Such as isobutyl acrylate (meth) acrylic acid _{C 1-20} alkyl, preferably (meth) acrylic acid _{C 1-10} alkyl) (meth) acrylic acid esters and the like; either alone or co-of (meth) acrylamide, etc.] Polymer; heat or photo-curable acrylic resin}, olefin resin (for example, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene- (meth) acrylic acid ester copolymer, etc.), Vinyl ester resins (eg, polyvinyl acetate, polyvinyl alcohol, etc.), halogen-containing resins (polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, etc.), polyester resins (polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate) Aromatic polyester resins such as aliphatic Polyester resins, etc.), polyurethane resins, polyamide resins, polyimide resins, polysaccharides or derivatives thereof [for example, cellulose derivatives (eg, cellulose esters such as cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate; Cellulose ethers such as methylcellulose, ethylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose; nitrocellulose, starch, guar gum, gum arabic, sodium alginate, etc.], rubber or elastomer (for example, acrylic rubber, Butadiene rubber, styrene-butadiene rubber, etc.).

  The resins may be used alone or in combination of two or more.

(Ratio of each component and zinc component)
In the composition of the present invention, the ratio between the white pigment and the glass can be selected from the range of the former / the latter (weight ratio) = 99/1 to 1/99 (for example, 95/5 to 5/95). It may be 90/10 to 10/90, preferably 80/20 to 20/80, more preferably about 75/25 to 25/75 (for example, 70/30 to 30/70), particularly 65/35. To about 25/75 (for example, 65/35 to 30/70, preferably 60/40 to 35/65, and more preferably 55/45 to 40/60).

  The ratio of the resin is, for example, 1 to 100 parts by weight (for example, 2 to 80 parts by weight), preferably 3 to 70 parts by weight (for example, 5 to 60 parts by weight) with respect to 100 parts by weight of the total amount of white pigment and glass. ), More preferably about 10 to 50 parts by weight (for example, 20 to 40 parts by weight).

  In the composition of the present invention, as described above, the glass contains at least zinc borosilicate glass. The ratio of zinc in such glass (zinc borosilicate glass) is, for example, in the range of 1% by weight or more (for example, about 1 to 90% by weight) in terms of ZnO with respect to the total amount of white pigment and glass. For example, 1.5% by weight or more (for example, 1.5 to 80% by weight), preferably 2% by weight or more (for example, 2 to 60% by weight), more preferably 3% by weight or more (for example, 3% ˜50 wt%), in particular, about 4 wt% or more (eg, 4 to 40 wt%, preferably 5 to 35 wt%).

  Moreover, the ratio of zinc in the zinc borosilicate glass is, for example, 1 to 500 parts by weight (for example, 3 to 400 parts by weight), preferably 5 to 300 parts by weight (in terms of ZnO) with respect to 100 parts by weight of the resin. For example, it may be about 8 to 250 parts by weight), more preferably about 10 to 200 parts by weight (for example, 15 to 150 parts by weight), and usually 5 to 200 parts by weight (for example, 8 to 180 parts by weight, preferably 10 to 150 parts by weight).

(Other ingredients)
In particular, the composition of the present invention may be a composition containing a solvent (or a dispersion medium) in order to easily form a film. The solvent can be selected according to the type of resin and the like, and a solvent that gives an appropriate viscosity to the composition and can be easily removed (volatilized) by a drying treatment or the like can be suitably used.

Typical solvents include, for example, alcohols {eg, saturated or unsaturated fatty alcohols (eg, heptanol, octanol, decanol, lauryl alcohol, tetradecyl alcohol, cetyl alcohol, octadecyl alcohol, hexadecenol, oleyl alcohol). C _6-30 aliphatic alcohols, preferably saturated or unsaturated C _8-24 aliphatic alcohols), alicyclic alcohols [eg, cycloalkanols such as cyclohexanol; terpene alcohols such as terpineol and dihydroterpineol ( For example, monoterpene alcohol etc.), araliphatic alcohols (eg benzyl alcohol, phenethyl alcohol etc.), phenols [eg cresol (metacresol etc.) Etc.], polyhydric alcohols (ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycols such as (poly) C _2-4 alkylene glycols such as triethylene glycol; multi having 3 or more hydroxyl groups such as glycerin Etc.}, glycol ethers (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol) Monomethyl ether, dipropylene glycol monomethyl ether, triplicate (Poly) alkylene glycol monoalkyl ethers such as pyrene glycol butyl ether; (poly) alkylene glycol monoaryl ethers such as 2-phenoxyethanol), glycol ether esters (eg, ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, (Poly) alkylene glycol monoalkyl ether acetates such as diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate), hydrocarbons [eg aliphatic hydrocarbons (eg tetradecane, octadecane, heptamethylnonane) , Saturated or unsaturated aliphatic such as tetramethylpentadecane Hydrocarbons), aromatic hydrocarbons (eg, toluene, xylene (paraxylene, etc.), etc.), ketones (eg, chain ketones, such as acetone and diacetone alcohol; cyclic ketones, such as isophorone), ethers (For example, cyclic ethers such as tetrahydrofuran and dioxane), esters [for example, lactic acid esters (for example, ethyl lactate), fatty acid esters such as acetic acid esters (for example, benzyl acetate, isoborneol acetate); benzoic acid esters (benzoic acid) Aromatic carboxylic acid esters such as methyl and ethyl benzoate], nitrogen-containing solvents [eg, amides (eg, formamides such as dimethylformamide), imidazoles (eg, dimethylimidazole, etc.), dimethylimidazolidinone, etc. ] Etc. are mentioned.

  The solvents may be used alone or in combination of two or more.

  Preferred solvents include terpene alcohols, glycol ethers, glycol ether esters and the like because they have a high boiling point and a low vapor pressure, and thus are difficult to evaporate during printing.

  In the composition containing a solvent, the solid content (total amount of white pigment, glass and resin) is, for example, 20% by weight or more (for example, 25 to 97% by weight), preferably 30% by weight or more (for example, 35 to 35%). 95% by weight), more preferably 40% by weight or more (eg 45 to 90% by weight), particularly 50% by weight or more (eg 55 to 85% by weight), and usually 30 to 90% by weight ( For example, it may be about 40 to 85% by weight, preferably about 50 to 80% by weight. In particular, the composition containing a solvent may be a composition containing a solid content at a relatively high concentration (a paste-like composition).

  The viscosity of the composition containing the solvent (particularly the paste-like composition) can be selected according to the application, the coating method to be applied, etc., but usually at 25 ° C., 0.5 Pa · s or more (for example, 1 to 400 Pa · s). s), preferably 3 Pa · s or more (eg, 5 to 300 Pa · s), more preferably about 10 to 250 Pa · s (eg, 20 to 200 Pa · s), and usually about 1 to 300 Pa · s. It may be.

  In addition to the above components, the composition of the present invention may contain various additives [for example, stabilizers (antioxidants, ultraviolet absorbers, etc.), surfactants or dispersants, dispersion stabilizers as necessary. , Thickeners or viscosity modifiers, antifoaming agents, etc.]. These additives can be used alone or in combination of two or more.

[Reflective substrate and manufacturing method thereof]
The composition of the present invention is suitable as a composition (a composition for forming a reflective film) for forming a film (a coating film or a film), particularly a reflective film (or a reflective layer) on a substrate (on the substrate). . Hereinafter, the reflective film (reflective substrate) will be described in detail.

  The reflective substrate of the present invention can be obtained by forming a film on the substrate with the composition of the present invention and then firing (or sintering) the substrate. That is, the reflective substrate is composed of a substrate (or base material) and a sintered film (reflective film) of the composition formed on the substrate. In the reflective film, the resin is decomposed by the sintering process, and a dense film is formed of the white pigment and the glass. That is, the film of the composition before sintering formed on the substrate can also be referred to as a precursor of the reflective film (unsintered film).

  The substrate only needs to have heat resistance capable of withstanding the baking treatment, and can be selected depending on the type of glass (such as baking or sintering temperature). Such a substrate may be an organic material, but may usually be an inorganic material. Examples of the inorganic material include metal nitride (for example, aluminum nitride), metal oxide (alumina, sapphire, zirconia, titania, yttrium oxide, indium oxide-tin oxide composite oxide (ITO), fluorine-doped tin oxide, and the like. (FTO) etc.). In particular, when a substrate made of aluminum nitride (aluminum nitride substrate) is used, the reflective substrate can be used as an LED element (or a constituent material thereof).

  If necessary, the surface of the substrate is subjected to oxidation treatment [surface oxidation treatment, for example, discharge treatment (corona discharge treatment, glow discharge, etc.), acid treatment (chromic acid treatment, etc.), ultraviolet irradiation treatment, soot treatment, etc., surface Surface treatment such as uneven treatment (solvent treatment, sandblast treatment, etc.) may be performed.

  In addition, the maximum value of the reflectance in a visible light region (for example, a region having a wavelength of 380 to 800 nm) of a substrate (particularly, an aluminum nitride substrate) is, for example, 50% or less (for example, 10 to 50%), preferably 45%. It may be below (for example, 15 to 45%), more preferably about 40% or less (for example, 20 to 35%).

  What is necessary is just to select the thickness of a board | substrate suitably according to a use, for example, 0.05-10 mm, Preferably it is 0.1-5 mm, More preferably, it may be about 0.2-3 mm.

  The method for forming the film on the substrate is not particularly limited, and may be a method of applying a composition not containing a solvent (powder composition). Usually, a composition containing a solvent is applied (coating). It may be a method. As an application method, for example, a conventional method such as a flow coating method, a spin coating method, a spray coating method, a screen printing method, a flexographic printing method, a casting method, a bar coating method, a curtain coating method, a roll coating method, a gravure coating method, A dipping method, a slit method, a photolithography method, an ink jet method, or the like can be used. Of these coating methods, when drawing a pattern, for example, screen printing, ink jet printing, intaglio printing (eg, gravure printing), offset printing, intaglio offset printing, flexographic printing, etc. are widely used. Is done.

  The thickness of the film (unsintered film) can be selected according to the application, for example, 1 to 10000 μm (for example, 1 to 1000 μm), preferably 3 to 500 μm (for example, 3 to 300 μm), and more preferably 5 to 200 μm ( For example, about 10-100 micrometers) may be sufficient.

  The substrate on which the film is formed is a precursor of the reflective substrate, and is subjected to a baking process in which the film (film or pattern) is heated (or baked or heat-treated) at a predetermined temperature. In addition, you may perform a drying process as needed prior to heat processing.

  The firing temperature (sintering temperature) can be selected according to the type of glass (melting temperature of glass), the type of resin (decomposition temperature of resin), and the like, for example, 400 ° C. or higher (eg, 500 to 1600 ° C.), preferably May be 600 ° C. or higher (for example, 650 to 1300 ° C.), more preferably 700 ° C. or higher (for example, 800 to 1200 ° C.), particularly about 800 to 1100 ° C. (for example, 850 to 1000 ° C.). The holding time (calcination time) at the firing temperature may be, for example, 1 minute to 5 hours, preferably 3 minutes to 1 hour, and more preferably about 5 minutes to 30 minutes.

  The baking treatment may be performed in an oxidizing atmosphere, but in order to prevent the substrate from being oxidized depending on the application, a non-oxidizing atmosphere [for example, inert gas such as nitrogen, rare gas (helium, neon, argon, etc.) Gas] may be performed. In the present invention, even when baking treatment is performed in such a non-oxidizing atmosphere, the resin can be efficiently decomposed to form a sintered film of white pigment and glass.

  The thickness of the obtained reflective film (or sintered film, coating film after baking, baking pattern) can be appropriately selected from the range of about 0.01 to 10000 μm depending on the application, for example, 0.01 to 5000 μm (for example, 0.1 to 500 μm), preferably 1 to 400 μm (for example, 2 to 300 μm), more preferably about 3 to 150 μm (for example, 5 to 100 μm).

  The reflective substrate of the present invention obtained by such a method is composed of a substrate and a reflective film (fired film of the composition) formed on the substrate, and has high whiteness, high strength, etc. It has excellent characteristics.

  For example, the maximum value of the reflectance in the visible light region (for example, a region having a wavelength of 380 to 800 nm) of the reflective substrate (or reflective film) of the present invention is, for example, 50% or more (for example, 55 to 100%), preferably May be 60% or more (for example, 65 to 99%), more preferably 70% or more (for example, 70 to 98%), and 75% or more [for example, 75 to 99%, preferably 80% or more. (For example, 82 to 98%), more preferably 85% or more (for example, 87 to 97%)].

  Moreover, the pencil hardness of the reflective substrate (or reflective film) of the present invention is, for example, H or higher (for example, 2 to 12H), preferably 3H or higher (for example, 3 to 11H), more preferably 4H or higher (for example, 5H or higher [e.g., 5-12H, preferably 6H or higher (e.g., 7-12H), more preferably 8H or higher (e.g., 8-10H)]. .

  In addition, as described above, the reflective substrate of the present invention can remarkably reduce the amount of resin and solvent residues in the reflective film, and can form a dense film of white pigment and glass. ing. Therefore, the reflective substrate (or reflective film) of the present invention is heated at a high temperature [for example, 200 ° C. or higher (for example, 230 to 1000 ° C.), preferably 250 ° C. or higher (for example, 270 to 800 ° C.), more preferably 300 ° C. Even when exposed to the above (for example, 320 to 600 ° C.), the reflectance and pencil hardness as described above can be maintained (or not impaired). That is, the reflectance and pencil hardness after exposure of the reflective substrate of the present invention to a high temperature can be selected from the same ranges as described above.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

In the examples, the following components were used.
(White pigment)
Titanium oxide 1: Average particle diameter D50 = 0.3 μm, purity 93%
Titanium oxide 2: Average particle diameter D50 = 0.3 μm, purity 90%
Aluminum oxide 1: average particle diameter D50 = 1 μm, purity 99.99%
Aluminum oxide 2: Average particle diameter D50 = 7 μm, purity 99.8%
(Glass)
Glass 1: Zinc borosilicate glass frit, ZnO content 23% by weight, B ₂ O ₃ content 12% by weight, SiO ₂ content 34% by weight, ZrO ₂ content 7% by weight, Ti ₂ O content 4% by weight, others 20% by weight
Glass 2: Zinc borosilicate glass frit, ZnO content 58% by weight, B ₂ O ₃ content 30% by weight, SiO ₂ content 7% by weight, others 5% by weight
Glass 3: Zinc borosilicate glass frit, ZnO content 66% by weight, B ₂ O ₃ content 23% by weight, SiO ₂ content 6% by weight, others 5% by weight
Glass 4: Borosilicate glass frit, B ₂ O ₃ content 21% by weight, SiO ₂ content 45% by weight, others 34% by weight
Glass 5: Bismuth glass frit, Bi ₂ O ₃ content 46% by weight, SiO ₂ content 41% by weight, others 13% by weight
(resin)
Polyisobutyl methacrylate (weight average molecular weight 250,000)

(Examples and Reference Examples)
Resin (polyisobutyl methacrylate) was dissolved in an organic solvent (terpineol) heated to 60 ° C. with propeller stirring to obtain an organic vehicle. Each component (white pigment, glass frit, organic vehicle) was weighed into a plastic container so as to have the composition (weight ratio) shown in the table. A plastic container was covered, and the mixture was stirred and mixed at 1000 rpm for 10 minutes using a rotating and rotating stirrer to obtain a paste-like sample [viscosity 120 Pa · s (temperature: 25 ° C., measurement method: E-type viscometer used)]. . The produced paste was screen-printed on the surface of an aluminum nitride substrate (reflectance 30%) and then baked in nitrogen for 1 hour including the temperature raising and lowering process. Firing was carried out under conditions of a temperature rising rate of 36 ° C./min and a temperature falling rate of 36 ° C./min, and held for 10 minutes at a peak temperature of 900 ° C. The film thickness of the obtained reflective film was 30 μm.

  And the color and various characteristics of the obtained reflective film were evaluated before and after heat treatment (1 hour at 350 ° C.). The results are shown in the table. The reflectance was measured using a spectrophotometer (manufactured by Shimadzu Corporation, “UV-3100PC”), and the maximum value of the reflectance in the visible light range was shown in the table. The pencil hardness was measured according to JIS-K5600-5-4.

  The overall evaluation in the table is for a solid pattern (30 mm × 30 mm pattern) portion with a side of 30 mm, white color by visual observation, a maximum reflectance of 70% or more in the visible light region, and pencil hardness The case where 3H or more was satisfied was marked with ◯, and the others were marked with x.

  Moreover, the graph which shows each reflectance (before heat processing) in the visible light region of the solid pattern obtained in Example 2 and the solid pattern obtained in Example 7 measured by the spectrophotometer in FIG. 1 is shown. In FIG. 1, the reflectance of the aluminum nitride substrate is also shown for comparison.

  As is apparent from the results of the table, in the examples, a hard reflective film excellent in whiteness is obtained, and such a reflective film is a film whose reflectance does not decrease even when heated at high temperature. all right.

Since the composition of this invention can provide the outstanding reflectivity, it is useful in forming the reflective film of various uses. In particular, it is possible to form a film with high strength, high heat resistance, and high reflectance even if sintering is performed in a non-oxidizing atmosphere (for example, an inert gas atmosphere). Is suitable as a composition for forming a reflection film on a substrate of an LED element, for example.

Claims (13)

  A composition comprising a white pigment, glass, and a resin, wherein the glass comprises zinc borosilicate glass.   The composition according to claim 1, wherein the white pigment contains at least one selected from a titanium compound, a zirconium compound, and an aluminum compound.   The composition according to claim 1 or 2, wherein the white pigment is a particle having an average particle diameter (D50) of 0.05 to 20 µm.   The composition in any one of Claims 1-3 in which glass contains the zinc borosilicate glass which contains zinc 10weight% or more in conversion of ZnO.   The ratio of the white pigment to the glass is the former / the latter (weight ratio) = 95/5 to 5/95, and the ratio of the resin is 3 to 70 parts by weight with respect to 100 parts by weight of the total amount of the white pigment and the glass. The composition according to any one of claims 1 to 4.   The white pigment is particles having an average particle diameter (D50) of 0.1 to 10 μm including at least one selected from titanium oxide, zirconium oxide and aluminum oxide, and the glass contains zinc in an amount of 15 to 75% by weight in terms of ZnO. Including zinc borosilicate glass, the ratio of the white pigment to the glass is the former / the latter (weight ratio) = 80/20 to 20/80, and the ratio of the resin is 100 parts by weight of the total amount of the white pigment and the glass. The composition according to any one of claims 1 to 5, which is 10 to 50 parts by weight.   The composition according to any one of claims 1 to 6, wherein the proportion of zinc is 5 to 300 parts by weight in terms of ZnO with respect to 100 parts by weight of the resin.   Furthermore, it is a paste-like composition containing a solvent, The composition in any one of Claims 1-7.   The composition according to claim 1, which is a composition for forming a reflective film for forming a reflective film on a substrate.   The composition according to claim 9, wherein the substrate is an aluminum nitride substrate.   The manufacturing method of the reflective substrate which forms a film | membrane with the composition in any one of Claims 1-10 on a board | substrate, and performs a baking process.   The manufacturing method according to claim 11, wherein an aluminum nitride substrate is used and the baking treatment is performed at 600 ° C. or higher in a non-oxidizing atmosphere.   A reflective substrate obtained by the method according to claim 11.

Images