JP2005243319A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish specifications satisfying a reflection preventing property and mechanical durability such as surface hardness in an lighting device forming a reflection preventing coating using a coating composition containing hollow fine particles and a matrix forming material. <P>SOLUTION: The lighting device is equipped with a light source and a front cover 4 transmitting light irradiated from the light source. The reflection preventing coating 5 is formed using a coating composition composed of hollow fine particles 6 and a matrix forming material forming a porous matrix 7 on the surface 4a of the light incident side of the front cover 4. A refractive index of the reflection preventing coating 5 is from 1.25 to 1.35, its film thickness from 92 to 120nm, a blending ratio of the hollow particles/matrix forming material of the coating composition from 40/60 to 70/30 in a weight ratio, and trialkoxy fluorosilane and/or silicone oil are added, so that the reflection preventing coating 5 capable of withstanding a practical use level can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illuminating device, and more particularly, to an illuminating device in which an antireflection coating for preventing reflection of visible light is formed on a translucent member that transmits light emitted from a light source.

  In a lamp having a general arc tube and a luminous filament, a low refractive index material is coated on the front cover (transparent glass or transparent resin) of the lamp bulb or the light source unit to form an antireflection coating in order to increase the irradiation efficiency. How to do is known.

Examples of anti-reflective coating to the front _{cover, SiO 2, SiO, TiO 2} , CeO, Al 2 O 3, Sb 2 O 3, La 2 O 3, Nd 2 O 3, Pr 6 O 11, ThO 2, A method of forming a single film layer of a metal oxide such as ZrO (for example, see Patent Document 1) and a method of forming a single film layer of a fluoride film such as MgF ₂ , CaF ₂ , LiF, and BaF ₂ are known. Yes.

As the low refractive index material, MgF ₂ (refractive index 1.38) and SiO ₂ (refractive index 1.47) are typical in the case of inorganic materials, and perfluororesin (refractive index in the case of organic materials). 1.34 to 1.40). Usually, MgF ₂ is a PVD method (Physical Vapor Deposition) such as vacuum deposition or sputtering, and SiO ₂ is a PVD method similar to MgF ₂ , or a CVD (Chemical Vapor Deposition), or a liquid phase method using Sol-Gel method. The perfluoro resin is formed by a liquid phase method. However, the perfluoro resin has no durability in a high temperature atmosphere exceeding 300 ° C. near the lamp, and it is difficult to apply it to the front cover of the light source unit and the lamp bulb.

  By the way, the most common example of practical use of the antireflection coating is a display. In the case of using a low refractive index material as described above for the purpose of preventing reflection of an image display panel such as a display, in most cases, two layers of a high refractive index material layer and a low refractive index material layer are formed on the surface of a substrate such as glass. By forming the above, antireflection performance is obtained. The difference in refractive index between the high-refractive index material and the low-refractive index material forming these layers is known to have a lower bottom value (minimum value) of reflectivity, although the appropriate range exists. ing.

  Conventionally, when a layer is formed on the surface of a soda glass substrate (refractive index 1.54), even if a perfluoro resin (refractive index 1.34), which is a material having the lowest refractive index at present, is used, it is refracted. The difference in the refractive index is only 0.20, and in order to obtain a large antireflection performance, a high refractive index material layer is required as an intermediate layer between the base material and the low refractive index material layer. However, if a material having a lower refractive index than that of perfluoro resin can be obtained, antireflection performance can be improved with only a single layer by coating this low refractive index material on the surface of a soda glass substrate. It is expected that

  On the other hand, spherical hollow silica-based fine particles having a refractive index lower than that of perfluororesin are known (for example, see Patent Document 2). It is known that the fine particle has a cavity (or cavity) surrounded by an outer shell (or shell), and the refractive index of the fine particle itself can be 1.30 or less. It has been suggested that a transparent film having a low refractive index can be formed by applying and drying a coating composition obtained by dispersing such hollow silica-based fine particles in a matrix-forming material.

  A coating composition using such hollow silica-based fine particles has a lower refractive index than metal oxides and metal fluorides, and is superior to perfluororesin in high temperature durability. When used in a lighting device to prevent reflection, there is a possibility that the irradiation efficiency can be increased as compared with the conventional case.

In addition, in order to form a coating film having a low refractive index in a coating composition containing hollow fine particles and a matrix-forming material, the inventors have important that the matrix-forming material has a property of forming a porous matrix. (For example, refer to Patent Document 3).
JP 2002-352608 A JP 2001-233611 A JP 2003-201443 A

  By forming an antireflection coating on the lighting device using the coating composition containing the hollow fine particles and the matrix forming material as described above, there is a possibility that the transmission efficiency of the lamp light can be further increased, and a highly efficient lighting device is obtained. There is a possibility that can be made. However, in order to improve the antireflection performance, it is necessary to add the hollow fine particles to a certain amount or more. On the other hand, when the composition satisfies the antireflection performance, the film strength of the antireflection coating is extremely reduced. When the anti-reflection coating is formed on the illuminating device, the anti-reflective effect may be lost during handling, or the light distribution characteristics of the illuminating device may be damaged by the scratch. Specific technical matters that satisfy mechanical durability such as hardness are not sufficient.

  The present invention solves the above problems, and in an illumination device in which an antireflection coating is formed using a coating composition comprising hollow fine particles and a matrix forming material, a machine such as antireflection characteristics and surface hardness is provided. The purpose is to provide a highly efficient lighting device by establishing specifications that satisfy the requirements of mechanical durability (countermeasures against scratches during handling).

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have disclosed an anti-reflection characteristic and a machine in an illuminating device in which an anti-reflection coating is formed using a coating composition comprising hollow fine particles and a matrix forming material. The refractive index of the antireflection coating and the film thickness, and the blending ratio of the hollow fine particles and the matrix forming material, which can be endured at a practical level both in terms of mechanical durability, were found. Furthermore, it has been found that the mechanical durability can be further improved by adding trialkoxyfluorosilane and / or silicone oil to the coating composition to improve the slipping property of the antireflection coating surface.

  The invention of claim 1 includes a light source and a translucent member that is disposed at a position facing the light source and transmits light emitted from the light source, and the surface on the light incident side of the translucent member is formed with hollow fine particles. And an illumination device formed with an antireflection coating for antireflection of visible light by coating with a coating composition comprising a matrix-forming material that forms a porous matrix, The refractive index is 1.25 to 1.35. “Hollow particulate” means a particle having a cavity surrounded by an outer shell. Such hollow fine particles are disclosed in, for example, Patent Document 2, and the hollow fine particles disclosed therein can be used in the coating composition of the present invention. “Porous matrix” means a state in which an antireflective coating formed using a coating composition includes a large number of fine voids in a matrix that exists around hollow fine particles and acts as a binder. .

  According to a second aspect of the present invention, in the optical member according to the first aspect, the antireflection coating is a single layer film, and the film thickness is 92 to 120 nm.

  According to a third aspect of the present invention, in the optical member according to the first aspect, the hollow fine particles are silica-based inorganic oxides, and the matrix forming material forms a silicon compound having a siloxane bond, or the antireflection coating. The coating composition is characterized in that the weight ratio of the hollow fine particles to the matrix forming material is 40/60 to 70/30. Here, “silica-based inorganic oxide” means (A) a silica single layer, (B) a single layer of a composite oxide composed of silica and an inorganic oxide other than silica, and (C) the (A) layer. And (B) a layer including a double layer.

  According to a fourth aspect of the present invention, there is provided the optical member according to the third aspect, wherein the coating composition comprises 5 to 20 trialkoxyfluorosilanes based on the total weight of the active ingredients of the hollow fine particles and the matrix-forming material. The trialkoxyfluorosilane and the matrix forming material are copolymerized by weight%.

  According to a fifth aspect of the present invention, in the optical member according to the fourth aspect, the coating composition has a silicone oil content of 0.1 to 10 with respect to the total weight of the active ingredients of the hollow fine particles and the matrix-forming material. It is characterized by being mixed by weight%.

  According to a sixth aspect of the present invention, the light incident side surface and the light output side surface of the translucent member are coated with the coating composition according to any one of the third to fifth aspects. An antireflection coating of a single film layer having a film thickness of 92 to 120 nm is formed on the light incident side surface and the light emission side surface of the translucent member.

  According to the first aspect of the present invention, since the refractive index of the antireflection coating is controlled to 1.25 to 1.35, the reflection can withstand a practical level in terms of mechanical durability such as antireflection characteristics and surface hardness. A lighting device with a prevention coating can be obtained. When the refractive index is 1.35 or more, the performance is the same as that of a perfluoro resin, and when the refractive index is 1.25 or less, mechanical durability that can withstand practical use cannot be obtained.

  According to the second aspect of the present invention, since the refractive index of the antireflection coating is set to 1.25 to 1.35 and the film thickness thereof is set to 92 to 120 nm, the visibility curve region 500 particularly in the visible light wavelength range of 380 to 780 nm. An antireflective coating can be formed that exhibits a transmittance peak at ˜600 nm. This is because when the anti-reflection coating process in which the peak of transmittance is generated as described above, the optical film thickness nd (n: refractive index, film thickness: d) is a quarter of the peak wavelength (λ). This is because such conditions are the best. When the film thickness is outside the above range, the peak shifts to the low wavelength side or the long wavelength side, and the antireflection effect decreases.

  According to the invention of claim 3, since the blending ratio of the hollow fine particles and the matrix forming material is 40/60 to 70/30 by weight ratio, it is a practical level in terms of mechanical durability such as antireflection characteristics and surface hardness. It is possible to obtain a lighting device having an anti-reflection coating that can withstand When the amount of hollow fine particles added is less than the above-mentioned blending ratio, the refractive index becomes 1.35 or more and the performance is not different from that of a perfluoro resin. When the amount of hollow fine particles added is larger than the above-mentioned blending ratio, the matrix forming material has. Since it becomes difficult to obtain the mechanical durability, the surface hardness is reduced, so that scratches are easily formed.

  According to the invention of claim 4, the trialkoxyfluorosilane is added in a weight ratio of 5 to 20% with respect to the total weight of the active ingredients of the hollow fine particles and the matrix forming material, and is reflected by copolymerization with the matrix forming material. Since the slipping property of the surface of the prevention coating is improved, it is possible to prevent the surface from being damaged when the lighting device is handled. When the addition amount of trialkoxyfluorosilane is 5% or less, the slipping effect is hardly exhibited, and when 20% or more is added, the refractive index becomes 1.35 or more and the antireflection effect is lowered.

  According to the invention of claim 5, since the silicone oil is mixed in an amount of 0.1 to 10% by weight with respect to the total weight of the active ingredients of the hollow fine particles and the matrix forming material, the slipping property of the antireflection coating surface is further improved. improves. When the amount of silicone oil added is 0.1% or less, the slipping effect is not improved, and when it is 10% or more, the refractive index becomes 1.35 or more and the antireflection effect is lowered.

  According to the sixth aspect of the present invention, by forming the antireflection coating on the light emitting side surface of the translucent member in addition to the light incident side surface of the translucent member, the antireflection characteristics and mechanical properties of the lighting device can be obtained. The durability can be further increased.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. As shown in FIGS. 1 and 2 (a) and 2 (b), the illumination device 1 is disposed at a position facing the light source 3 surrounded by the lamp bulb 2 and the light source 3, and is irradiated from the light source 3. A front cover (translucent member) 4 that transmits light is provided. On the light incident side surface 4 a of the front cover 4, an antireflection coating 5 for preventing visible light reflection is formed using a coating composition. The coating composition includes a hollow fine particle 6 and a matrix-forming material that forms a porous matrix 7.

  First, the matrix forming material will be described. The matrix-forming material is a silicon compound having a siloxane bond (referred to as “silicon compound (1)” for simplicity) or a silicon compound that can newly introduce a siloxane bond in the process of forming the antireflection coating (for simplicity. (Referred to as “silicon compound (2)”). The latter silicon compound (2) may already have a siloxane bond. These silicon compound (1) and silicon compound (2) include organic silicon compounds (that is, silicon compounds having an organic group), halogenated silicon compounds (for example, compounds containing halogen such as chlorine and fluorine), and organic compounds. Examples include silicon halide compounds (that is, compounds containing an organic group and halogen).

（式中、Ｒ^Ｉ は同一、又は異種の置換、若しくは非置換の炭素数１〜９の１価炭化水素基又はフェニル基を示し、ｎは０〜２の整数、Ｙは加水分解可能官能基を示す。）で表される加水分解可能オルガノシラン、それが加水分解して生成する化合物（部分加水分解して生成するものをも含む）、その加水分解物が縮合して生成する化合物等を挙げることができる。 Examples of the silicon compound that can be used as the matrix forming material include the general formula (A):

(Wherein R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 9 carbon atoms or phenyl group, n is an integer of 0 to 2, and Y is a hydrolyzable functional group. A hydrolyzable organosilane represented by formula (1), a compound produced by hydrolysis (including those produced by partial hydrolysis), a compound produced by condensation of the hydrolyzate, and the like. Can be mentioned.

The group R ^I in the hydrolyzable organosilane represented by the general formula (A) represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 9 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and other alkyl groups; cyclopentyl group, cyclohexyl group and other cycloalkyl groups; 2-phenylethyl group, 2-phenylpropyl group, 3-phenylpropyl group Aralkyl groups such as phenyl groups, tolyl groups; alkenyl groups such as vinyl groups and allyl groups; chloromethyl groups, γ-chloropropyl groups, 3,3,3-trifluoropropyl groups, etc. Halogen-substituted hydrocarbon group; γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, γ-mercapto It can be exemplified propyl substituted hydrocarbon group such group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable because of easy synthesis or availability.

  Examples of Y of the hydrolyzable functional group include an alkoxy group, an acetoxy group, an oxime group (—O—N═C—R (R ′)), and an enoxy group (—O—C (R) ═C (R ′) R. ”), An amino group, an aminoxy group (—O—N (R) R ′), an amide group (—N (R) —C (═O) —R ′) (in these groups, R, R ′, R "" Is, for example, each independently a hydrogen atom or a monovalent hydrocarbon group). Among these, an alkoxyl group is preferable from the viewpoint of availability.

  Examples of such hydrolyzable organosilanes include di-, tri-, and tetra-functional alkoxysilanes, acetoxysilanes, wherein n in the general formula (A) is an integer of 0 to 2. Examples include oxime silanes, enoxy silanes, amino silanes, aminoxy silanes, and amido silanes. Among these, alkoxysilanes are preferable because of their availability. Particularly, tetramethoxysilane, tetraethoxysilane and the like can be exemplified as tetraalkoxysilane of n = 0, and methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, n = 1 as organotrialkoxysilane, Examples thereof include phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane and the like. Examples of the diorganodialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane.

  When the matrix forming material of the coating composition of the present invention is a silicon compound that can newly bring about a siloxane bond, at least two groups selected from a hydrolyzable substituent and a hydroxyl group are bonded to the same or different silicon atoms. Preferably, it is a silicon compound. These at least two groups may be the same or different. The hydrolyzable substituent is hydrolyzed in the presence of water to form a compound having a hydroxyl group (silanol compound). Therefore, a silicon compound in which at least two of groups selected from a hydrolyzable substituent and a hydroxyl group are bonded to the same or different silicon atoms, is a group selected from a hydrolyzable substituent and a hydroxyl group in the presence of water. Condensation with the same or another type of silicon compound, at least two of which are bonded to the same or different silicon atoms, results in a new siloxane bond.

（式中、置換基Ｘ^１、Ｘ^２、Ｘ^３及びＸ^４は水素、ハロゲン（例えば塩素、フッ素等）、１価の炭化水素基、ＯＲ（Ｒは１価の炭化水素基である）で表されるアルコキシ基及びＯＨで表される水酸基から選択される基であり、これらは相互に異なっても、部分的に異なっても、あるいは全部同じであってもよく、これらの少なくとも２つは、それぞれアルコキシ基及び水酸基から選択される基である。）で表されるシラン化合物が挙げられる（本明細書において、これを「シラン化合物（１）」と呼ぶ）。このシラン化合物（１）は、少なくとも２つ、好ましくは３つ、より好ましくは４つの同じ、又は異なるアルコキシル基及び／又は水酸基を有する。マトリクス形成材料は、シラン化合物（１）の少なくとも１つのアルコキシル基が加水分解されているものであってもよい。 As an example of the matrix forming material corresponding to the silicon compound (2), the general formula (1):

Wherein the substituents X ¹ , X ² , X ³ and X ⁴ are hydrogen, halogen (eg, chlorine, fluorine, etc.), a monovalent hydrocarbon group, OR (R is a monovalent hydrocarbon group). A group selected from an alkoxy group represented by and a hydroxyl group represented by OH, which may be different from each other, partially different or all the same, at least two of which are , Each of which is a group selected from an alkoxy group and a hydroxyl group) (in this specification, this is referred to as “silane compound (1)”). This silane compound (1) has at least 2, preferably 3, more preferably 4 identical or different alkoxyl groups and / or hydroxyl groups. The matrix forming material may be one in which at least one alkoxyl group of the silane compound (1) is hydrolyzed.

  Examples of matrix-forming materials corresponding to the silicon compound (1) include siloxanes formed by condensation after one or more of the silane compounds (1) are hydrolyzed if they can be hydrolyzed. Compound or polysiloxane compound (in the present specification, these are collectively referred to as “(poly) siloxane compound (1)”). The polysiloxane compound means a compound having two or more siloxane bonds. The (poly) siloxane compound (1) preferably has at least two alkoxy groups and / or hydroxyl groups as substituents (in the present specification, such (poly) siloxane compound is referred to as “(poly) siloxane compound ( 2) "), in which case this (poly) siloxane compound already has a siloxane bond but corresponds to the silicon compound (2).

  In addition, when the above-mentioned silane compound (1) and (poly) siloxane compound (2) have an alkoxyl group, they can have a hydroxyl group produced by hydrolysis of the alkoxyl group. As a result, these silane compound (1) and (poly) siloxane compound (2) can also form a porous matrix 7 by at least partially condensing and crosslinking when the coating composition is applied and dried. . Therefore, at the time of this condensation, not all of the generated hydroxyl groups are involved in the condensation, and in general, some hydroxyl groups remain as they are. The (poly) siloxane compound (1) is a porous matrix that does not condense when the coating composition is applied and dried even when it does not have an alkoxy group and / or a hydroxyl group substituent. 7 can be formed.

  Thus, the silane compound (1) and the (poly) siloxane compound (2) are crosslinked to form a porous matrix 7 matrix. When the hydroxyl group of the substituent or the substituent is an alkoxy group, Hydroxyl groups formed by hydrolysis of silicon compounds cause cross-linking by condensation of silicon compounds, and those remaining without participating in cross-linking function as hydrophilic groups and adhere to substrates such as the front cover 4 Can be improved. Also, the antireflection coating becomes difficult to be charged.

  Such a silane compound (1) preferably has a molecular weight of 40 to 300, more preferably 100 to 200. The (poly) siloxane compound (1) and (poly) siloxane compound (2) described above preferably have a weight average molecular weight of about 200 to 2000 when mechanical strength of the dry film is required. 600 to 1200 is more preferable. A molecular weight in this range tends to easily improve the strength of the dry film and increase the porosity of the matrix 7 matrix (ie, the proportion of voids in the matrix 7 matrix). Here, the “dry film” is a solid film obtained so that the liquid component of the coating film formed by applying the coating composition does not substantially remain.

  The (poly) siloxane compound (1) and the (poly) siloxane compound (2) described above preferably have a weight average molecular weight of about 2000 or more when a large mechanical strength is not required for the dry film. More preferably, it is 3000 or more, for example, 3000 to 5000. When the molecular weight is higher in this way, the hydrolysis reaction proceeds further, there is almost no unreacted alkoxy group, and the refractive index as the condensate becomes smaller along with the porosity of the dry film, so that the binder formed The refractive index tends to be lower.

  Such a matrix-forming material is used together with hollow fine particles in the form of a paint, applied to a substrate to form a coating film, and then dried to form a porous coating film. As described above, this drying may be performed together with heating.

Preferable examples of the silane compound (1) include tetrafunctional hydrolyzable organosilanes represented by SiX ₄ (X is a hydrolyzable monovalent organic substituent such as an alkoxyl group). Moreover, as a preferable example of the (poly) siloxane compound (1) or (poly) siloxane compound (2), tetrafunctional hydrolysis represented by SiX ₄ (X is a hydrolyzable organic substituent, for example, an alkoxy group). A compound having a siloxane bond, preferably a resin having a plurality of siloxane bonds formed by condensation of a partial hydrolyzate and / or a complete hydrolyzate of an organosilane (this compound and resin are collectively referred to as “ And specifically referred to as “SILICONE RESIN-M. Such“ silicone resin-M ”need not be the same as what is generally known as a silicone resin). Such a substance is included in the (poly) siloxane compound (1). When the silicone resin-M is a condensable having a hydroxyl group bonded to silicon or a hydrolyzable organic substituent, (poly) It corresponds to a siloxane compound (2).

The coating composition preferably contains hollow silica-based fine particles having an average particle diameter of 5 nm to 2 μm and silicone resin-M as essential components as hollow fine particles. In addition, complete hydrolyzate means that all hydrolyzable organic substituents are hydrolyzed, that is, tetrahydroxysilane (Si (OH) ₄ ), and partial hydrolyzate means other hydrolyzate. (Ie, di- or trihydroxysilane). Also about such silicone resin-M, it is preferable that a weight average molecular weight is about 200-2000, and it is more preferable that it is 600-1200.

  Silane compound (1), (poly) siloxane compound (1) and (poly) siloxane compound (2), tetrafunctional hydrolyzable organosilane and silicone resin-M as described above are applied to a substrate together with a solvent. In addition, it is preferable that the “film-like product” formed by drying this is hydrophilic. For example, it is applied to the surface of a quartz glass substrate so as to have a film thickness of 100 nm and dried, and at 100 ° C. It is preferable to be able to form a “film-like product” such that the surface water droplet contact angle of the cured film obtained by heat treatment is 20 ° or less, preferably 10 ° or less.

The above-mentioned silicone resin-M is a tetraalkoxysilane represented by SiX ₄ (X = OR, R is a monovalent hydrocarbon group), the molar ratio [H ₂ O] / [OR] is 1.0 or more, For example, a partial hydrolyzate obtained by hydrolysis in the presence of water in an amount of 1.0 to 5.0, preferably 1.0 to 3.0, and preferably in the presence of an acid or base catalyst, and It can be obtained using a complete hydrolyzate. In particular, a partially hydrolyzed product and / or a completely hydrolyzed product obtained by hydrolysis in the presence of an acid catalyst tend to form a two-dimensional cross-linked structure, and therefore the porosity of the dry film tends to increase. If the molar ratio is less than 1.0, the amount of unreacted alkoxyl groups increases, which may adversely affect the coating refractive index. Conversely, if it exceeds 5.0, the condensation reaction is extremely fast. The coating composition may become gelled. In this case, the hydrolysis may be performed under any suitable conditions. For example, these materials can be hydrolyzed by stirring and mixing at a temperature of 5 ° C. to 30 ° C. for 10 minutes to 2 hours. Further, in order to make the molecular weight 2000 or more and to reduce the refractive index of the matrix itself, the obtained hydrolyzate is reacted at 40 to 100 ° C. for 2 to 100 hours to obtain the desired silicone resin-M. Can be obtained.

As described above, when obtaining silicone resin-M, particularly silicone resin-M having a molecular weight of 2000 or more, SiX ₄ and water, diluted thinner (for example, alcohols such as methanol, ethanol, propanol, etc.) and other components (if present) For example, when the colloidal silica is used as a catalyst, the solid content (ie, Si contained in SiX ₄ ) of 5% by weight or more and 20% by weight or less of SiO _{2 with} respect to the total amount (ie, the total amount) of silica, etc. It is possible to use a partial hydrolyzate and / or hydrolyzate obtained by hydrolysis using an amount of SiX ₄ such that the total amount of SiO ₂ is converted to SiO _2. Particularly preferred. If the amount of SiX ₄ is less than 5% by weight, the amount of unreacted alkoxyl groups may increase even if the above amount of water is added, which may adversely affect the refractive index of the resulting matrix. On the other hand, if it exceeds 20% by weight, the coating composition may be gelled even if the above-mentioned amount of water is added.

Next, the hollow fine particles 6 will be described. As shown in FIG. 2B, the hollow fine particles 6 are those in which cavities 6b are formed inside the outer shell 6a, and any suitable known hollow fine particles may be used. More specifically, examples of the material constituting the outer shell of the hollow fine particles include SiO ₂ , SiO _x , TiO ₂ , TiO _x , SnO ₂ , CeO ₂ , Sb ₂ O ₅ , ITO, ATO, Al ₂ O _{3 and the} like. The form of a single material or a mixture of any combination of these materials can be exemplified. Further, a composite oxide of any combination of these materials may be used. Incidentally, SiOx, when firing in an oxidizing atmosphere, which becomes a SiO ₂ are preferred.

The hollow fine particles particularly preferably used are hollow fine particles having an outer shell made of silica-based inorganic oxide (hereinafter, such hollow fine particles are referred to as hollow silica-based fine particles). As the hollow fine particles, those having a thinner outer shell than the average particle diameter are preferably used, and the volume of the hollow fine particles in the coating is preferably large. The refractive index of the hollow microparticles themselves is preferably 1.20 to 1.40, more preferably 1.20 to 1.35. The refractive index of the hollow fine particles can be measured by the method disclosed in Patent Document 2. The outer diameter of the hollow fine particles is preferably 5 to 2000 nm, more preferably 20 to 100 nm. Here, the silica-based inorganic oxide is (A) a single layer of silica, (B) a single layer of a composite oxide composed of silica and an inorganic oxide other than silica, and (C) the (A) layer ( B) The thing including the double layer with a layer is said.

The outer shell may be porous with pores, or the pores may be closed and the cavity sealed with respect to the outside of the outer shell. The outer shell is preferably a plurality of silica-based coating layers including an inner first silica coating layer and an outer second silica coating layer. By providing the second silica coating layer on the outer side, it is possible to obtain hollow silica fine particles in which the outer shell is fined by closing the fine pores of the outer shell, and further, the inner cavity is sealed.

  The thickness of the outer shell is preferably in the range of 1 to 50 nm, particularly 5 to 20 nm. If the thickness of the outer shell is less than 1 nm, the hollow fine particles may not maintain a predetermined particle shape. On the other hand, when the thickness of the outer shell exceeds 50 nm, the cavities in the hollow fine particles are small, and as a result, the ratio of the cavities may be reduced and the refractive index may not be sufficiently lowered. Furthermore, the thickness of the outer shell is preferably in the range of 1/50 to 1/5 of the average particle diameter of the hollow fine particles. When the first silica coating layer and the second silica coating layer are provided as outer shells as described above, the total thickness of these layers may be in the range of 1 to 50 nm. For the outer shell, the thickness of the second silica coating layer is preferably in the range of 20 to 40 nm.

The cavity may contain a solvent used when preparing the hollow silica-based fine particles and / or a gas that enters during drying. Moreover, the precursor substance for forming the cavity mentioned later may remain in the cavity. The precursor material may remain slightly attached to the outer shell or may occupy most of the interior of the cavity. Here, the precursor material is a porous material that remains after a part of the constituent components of the core particle is removed from the core particle surrounded by the outer shell. As the core particles, porous composite oxide particles composed of silica and an inorganic oxide other than silica are used. Examples of the inorganic oxide include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ and WO ₃ . 1 type or 2 or more types can be mentioned. Examples of the two or more inorganic oxides include TiO ₂ —Al ₂ O ₃ and TiO ₂ —ZrO ₂ .

  The solvent or gas may be present in the pores of the porous material. When the removal amount of the constituent components of the core particles at this time increases, the volume of the cavity increases and hollow silica fine particles having a low refractive index are obtained. The transparent film obtained by blending the hollow silica fine particles has a low refractive index. Excellent anti-reflection performance.

  As described above, in the present invention, the average particle size of the hollow silica fine particles is in the range of 5 nm to 2 μm. If the average particle size is smaller than 5 nm, the effect of lowering the refractive index due to hollowness is small. Conversely, if the average particle size is larger than 2 μm, the transparency becomes extremely poor, and the contribution is due to diffuse reflection (Anti-Glare). Will become bigger. As an application in which a film formed using the coating composition of the present invention is required to have high transparency, for example, there is an antireflection application such as the outermost surface of a display. For this purpose, it is preferable that the hollow silica-based fine particles used have a particle diameter in the range of 5 to 100 nm. In addition, the particle diameter used in this specification is a number average particle diameter by transmission electron microscope observation.

  The method for producing hollow silica-based fine particles as described above is described in detail in Patent Document 2, and the hollow silica-based fine particles that can be used in the coating composition of the present invention are based on the method described therein. Can be produced, and commercially available hollow silica fine particles can also be used.

Next, a coating composition comprising hollow fine particles and a matrix forming material will be described. Preferred examples of the coating composition include, for example, the above-described hollow silica-based fine particles as hollow fine particles, and the tetrafunctional hydrolyzable organosilane represented by the above SiX ₄ (X is a hydrolyzable substituent) as a matrix forming material, At least one selected from the partial hydrolyzate and hydrolyzate thereof and the condensed product thereof (namely, silicone resin-M) is used. These matrix forming materials are all excellent in dispersion stability of hollow silica-based fine particles. Other metal oxide fine particles or organic hollow fine particles do not necessarily have sufficient dispersion stability, and the mechanical strength of the resulting dried coating tends to be smaller than that of silica hollow fine particles. However, even with other metal oxide fine particles or organic hollow fine particles, when the outermost surface of the outer shell is coated with a silica-based material, the dispersion stability and the mechanical strength of the dry film can be improved. Can be suitably used in the present invention. These tetrafunctional hydrolyzable organosilanes and materials derived therefrom are trifunctional hydrolyzable organosilanes, bifunctional hydrolyzable organosilanes, partial hydrolysates and hydrolysates thereof, and condensation of these silanes. As compared with the case where the resin thus produced is used as a matrix forming material, the refractive index of the obtained “film-like product” can be further reduced, and the cross-linking density of the coating can be further increased.

Examples of the tetrafunctional hydrolyzable organosilane preferably used as the matrix forming material of the coating composition include tetrafunctional alkoxysilanes represented by the following formula (2).

“R” of the alkoxyl group “OR” in the chemical formula (2) is not particularly limited as long as it is a monovalent hydrocarbon group, but a monovalent hydrocarbon group having 1 to 8 carbon atoms is preferable. is there. Examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a peptyl group, and an octyl group. Among the alkyl groups contained in the alkoxyl group, those having 3 or more carbon atoms may be linear such as n-propyl group, n-butyl group, isopropyl group, It may have a branch such as an isobutyl group or a t-butyl group.

  In preparing the silicone resin-M using a tetrafunctional hydrolyzable organosilane such as a tetrafunctional alkoxysilane, the tetrafunctional hydrolyzable organosilane is hydrolyzed (hereinafter also including partial hydrolysis) and condensed. Here, the weight average molecular weight of the obtained silicone resin-M is not particularly limited, but in order to obtain a higher mechanical strength of the obtained film with a smaller proportion of the silicone resin-M in the coating composition. The weight average molecular weight is preferably in the range of 200 to 2,000. If the weight average molecular weight is less than 200, the film-forming ability may be inferior. Conversely, if it exceeds 2000, the mechanical strength of the film may be inferior, but in applications that do not require such a large mechanical strength, the matrix itself In order to reduce the refractive index, a molecular weight of 2000 or more is effective. The molecular weight can be measured using GPC as described later.

In general, silicone resin-M obtained by hydrolyzing and condensing tetrafunctional hydrolyzable organosilane SiX ₄ has some unreacted groups, that is, hydrolyzable substituents X left in the molecule. It is condensed into a polymer (including oligomerization). In the case of forming a film using the coating composition of the present invention, the silicone resin-M as the matrix-forming material has unreacted groups remaining in the molecule, and as a result, the matrix formed is an unreacted substitution. However, when the film obtained by drying is heat-treated at a temperature exceeding 300 ° C. to obtain a cured film, unreacted groups are decomposed, so that the finally obtained cured film is refracted. There is no negative impact on the rate.

When the heat treatment is performed at a relatively low temperature such as 50 to 300 ° C., for example 50 to 150 ° C., particularly 50 to 120 ° C., the unreacted groups may remain in the cured film without being decomposed. As a result, there is a possibility that the refractive index as a matrix may be adversely affected. In view of this, the tetrafunctional hydrolyzable organosilane is used as a matrix-forming material in a completely hydrolyzed state rather than a partially hydrolyzed product, or is used in a completely hydrolyzed state as a silicone resin- It is preferable to prepare M and use it as a matrix-forming material. However, when a complete hydrolyzate is used, the matrix-forming material is generally a high-molecular substance having a molecular weight of 2000 or more, so that the resulting dried The mechanical strength of the coating is not always sufficient. In this case, it is effective for an application that does not require a great mechanical strength such as a display other than the outermost surface. Since the complete hydrolyzate has only —OH groups at the molecular ends, when a film is formed using this complete hydrolyzate, the only remaining group that the film can have is —OH. The surface of the coating is excellent in hydrophilicity, and the surface water droplet contact angle becomes small.

  Silicone resin-M having a molecular weight of 600 to 2000 is effective for applications requiring particularly high mechanical strength, and a partial hydrolyzate can be used to obtain silicone resin-M having this molecular weight range. The refractive index of the matrix itself formed from such a silicone resin-M is greater than when using a silicone resin-M obtained from a complete hydrolyzate, but a dry film formed from a low molecular weight silicone resin-M. Tends to be more porous. As a result, even if the ratio of the hollow silica-based fine particles / silicone resin-M condensate (ie, binder) in the dry film increases (thus, the refractive index of the film decreases), the mechanical strength of the film It is possible to keep When silicone resin-M having a molecular weight of 2000 or more is used, mechanical strength may not be expected regardless of the ratio of hollow silica-based fine particles / silicone resin-M condensate.

  Specifically, in the coating composition of the present invention, in applications that do not require so much mechanical strength, as the silicone resin-M used for the matrix forming material, this is applied to the surface of the quartz glass substrate. The cured film obtained by applying and drying to a thickness of 100 nm and heat-treating at 100 ° C. has a surface water droplet contact angle of 20 ° or less, preferably 10 ° or less (substantially lower limit is 0 °). Is preferably used. That is, when such a silicone resin-M is used as a matrix forming material, even if the coating is processed at a low temperature, no unreacted groups other than -OH remain, and it is easy to suppress an increase in the refractive index of the cured coating. Conversely, when using the silicone resin-M whose surface water droplet contact angle exceeds 20 °, the refractive index of the cured coating increases when the coating is not heat-treated at a higher temperature. It may be difficult to suppress this.

  When silicone resin M having a molecular weight of 2000 or less is used, even if the surface water droplet contact angle is measured by the method as described above, the surface water droplet contact angle does not become 20 ° or less. This is because unreacted groups remain in the matrix. The water droplet contact angle of the film formed from the coating composition of the present invention varies depending on the type of hollow fine particles used, the type of silicone resin-M, the molecular weight thereof, and the ratio of hollow fine particles / silicone resin-M condensate. When the hollow silica fine particles are used as the hollow fine particles and the silicone resin-M obtained from the partial hydrolyzate and / or hydrolyzate of the tetrafunctional alkoxysilane is used as the matrix forming material, the molecular weight of the silicone resin-M is When the contact angle of water droplets of the above-mentioned silicone resin-M alone dried film is larger than 2000 and the water droplet contact angle is 20 ° or less, it is cured regardless of the ratio of the hollow silica-based fine particles / silicone resin-M in the coating composition and the temperature at which the film is heat-treated. The surface water droplet contact angle of the coating is 20 ° or less. Further, when the molecular weight of the silicone resin-M is 2000 or less, regardless of the ratio of the hollow silica-based fine particles / silicone resin-M in the coating composition, if the coating is heat-treated at a high temperature of 300 ° C. or higher in an oxidizing atmosphere, The surface water droplet contact angle of the cured coating is 20 ° or less, but if the heat treatment temperature is 300 ° C. or less, the ratio of hollow silica-based fine particles / silicone resin-M in the coating composition is not 60/40 or more, The water droplet contact angle of the cured coating tends not to be 20 ° or less.

  In the present embodiment, the amount of hollow fine particles contained and the amount of matrix forming material may be any suitable ratio, but in general, the weight ratio of the weight of hollow fine particles to the matrix forming material (ie hollow The fine particle weight / matrix forming material weight) is preferably 40/60 to 70/30.

  The higher the proportion of hollow fine particles (for example, hollow silica-based fine particles) in the coating, the lower the refractive index of the coating, but the mechanical strength of the coating decreases. Therefore, it is necessary to increase the mechanical strength of the coating film by increasing the proportion of the hollow silica-based fine particles with the matrix material having a relatively small proportion. For this purpose, when tetrafunctional hydrolyzable alkoxysilane or condensable silicone resin-M derived therefrom is used as a matrix material (particularly when the molecular weight of silicone resin-M is 2000 or less), Can be condensed to improve the crosslinking density.

  In order to prepare the matrix-forming material, a silane compound (1), particularly a tetrafunctional hydrolyzable organosilane such as a tetrafunctional alkoxysilane, may be hydrolyzed, if necessary. The catalyst to be used is not particularly limited, but the obtained partial hydrolyzate and / or hydrolyzate is likely to have a two-dimensional cross-linked structure, the condensed compound is easily made porous, and required for hydrolysis. From the viewpoint of shortening the time, an acid catalyst (or an acidic catalyst) is preferable. Such an acid catalyst is not particularly limited, and examples thereof include organic acids (for example, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid. , Toluenesulfonic acid, oxalic acid, etc.), inorganic acids (eg, hydrochloric acid, nitric acid, halogenated silanes, etc.), acidic sol-like fillers (eg, acidic colloidal silica, oxidized titania sol, etc.). The above can be used.

  The hydrolysis of the alkoxide may be performed by heating as necessary (for example, when not so high mechanical strength is required), and in particular, hydrolysis is performed over 2 to 100 hours under the condition of 40 to 100 ° C. When the reaction is promoted, the number of unreacted alkoxide groups can be reduced as much as possible, and as a result, the refractive index of the matrix material itself is preferably lowered. If hydrolysis is performed outside the above temperature range or time range, unreacted alkoxide groups may remain. In place of the acidic catalyst, a basic catalyst (or basic catalyst) such as an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide or calcium hydroxide, an aqueous ammonia solution or an aqueous solution of amines is used. It may be used. However, when a base catalyst is used, an acid catalyst is preferred because it is easy to form a three-dimensional cross-link, resulting in a low porosity of the dry film and easy gelation. When the coating composition of the present invention has a hydrolyzable substituent as a matrix-forming material, it may contain such a hydrolysis catalyst.

  The coating composition of the present invention comprises the above-mentioned hollow fine particles, preferably hollow silica-based fine particles and the above-mentioned matrix forming material. It should be noted that the coating composition may be applied to a substrate to form a coating film, and at least partial hydrolysis of the matrix-forming material may occur. It is preferable to include a mixture of Examples of such other liquids include hydrophilic organic solvents, which include lower aliphatic alcohols such as methanol, ethanol, isopropanol (IPA), n-butanol, and isobutanol, ethylene glycol, and ethylene glycol mono Examples include ethylene glycol derivatives such as butyl ether and ethylene glycol monoethyl ether, diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. Moreover, 1 type, or 2 or more types selected from the group which consists of these can be used. Further, in combination with these hydrophilic organic solvents, one or more of toluene, xylene, hexane, heptane ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, etc. can be used. .

Depending on the coating composition, the resulting antireflective coating has hollow particulates and a porous matrix, the porosity of which is in the range of 10-95%, preferably 30-80%, more preferably 40-60%. When the porosity is particularly large, a film having a particularly low refractive index can be formed. When preparing the coating composition, the porosity in the above range can be achieved by variously changing the formulation of the hollow fine particles and the matrix-forming material to be blended. Here, the porosity is measured by XPS (X-Ray Photoelectron Spectroscopy) to measure the element type and average element ratio present as solids in the antireflection coating, and the true density ds of the solid part is calculated from the ratio. To do. Although hydrogen is not detected, hydrogen has a small atomic weight and can be ignored. Further, the film thickness of the antireflection coating is measured with an ellipsometer, and the weight of the coating is further determined. In order to reduce measurement errors, the substrate is preferably an aluminum foil, the substrate size is about 300 mm square, and the thickness of the coating film to be formed is preferably about 1 μm. The apparent coating volume is obtained from the thickness and area of the coating, and the apparent density of the coating: df is calculated from the weight of the coating and the apparent volume of the coating. The porosity is calculated based on the following formula. The porosity can be changed by adding other components as necessary.

  When the coating composition contains a matrix-forming material of the silane compound (1) and (poly) siloxane compound (2), the coating composition preferably contains a curing catalyst that crosslinks the matrix-forming material. As a result, when the coating composition is applied to a substrate to form a coating film and dried, the condensation reaction is promoted to increase the crosslinking density in the coating film, thereby improving the water resistance and alkali resistance of the coating film. There is an effect that can. Such curing catalysts include metal chelate compounds (eg, Ti chelate compounds, Zr chelate compounds, etc.), organic acids and the like. The metal chelate compound is particularly effective when the matrix forming material is prepared from tetrafunctional alkoxysilane.

A particularly preferable curing catalyst is organic zirconium, and it is particularly preferable to use it in view of the effect of the curing catalyst as described above. The organic zirconium is not particularly limited, for example, the general formula ^{_{ZrO n R 2 m (OR 1}} ) p (m, p is an integer of 0 to 4, n represents 0 or 1,2n + m + p = 4) Table The functional group (R ¹ ) of the alkoxyl group (OR ¹ ) in this chemical formula can be the same as in the formula (2). Examples of R ² include C ₅ H ₇ O ₂ (acetylacetonate complex) and C ₆ H ₉ O ₃ (ethyl acetoacetate complex). R ¹ and R ² may be the same or different in one molecule.

Particularly as organic zirconium, Zr (OC ₄ H ₉ ) ₄ , Zr (OC ₄ H ₉ ) ₃ (C ₅ H ₇ O ₂ ) and Zr (OC ₄ H ₉ ) ₂ (C ₅ H ₇ O ₂ ) (C ₆ When at least one of H ₉ O ₃ ) is used, the mechanical strength of the coating can be further improved. For example, when a coating is formed using a coating composition having a small ratio of silicone resin-M obtained by condensing (poly) siloxane compound (2), for example, tetrafunctional hydrolyzable alkoxysilane, to hollow silica-based fine particles. The mechanical strength of the coating film may be insufficient, but the mechanical strength of the coating film can be improved by adding organic zirconium. In addition, a cured film obtained by applying this coating composition to the substrate 4 and drying it at a relatively low temperature of 100 ° C. and then heat-treating it at that temperature is a film without adding organic zirconium. And having the same strength as usual when it is heat-treated at a high temperature exceeding 300 ° C.

The amount of the organic zirconium, it is preferred for the total solid content in the coating composition in terms of ZrO _2, from 0.1 to 10 wt%. If the addition amount is less than 0.1% by weight, the effect of organic zirconium may not be observed. Conversely, if the addition amount exceeds 10% by weight, the coating composition may be gelled or aggregated. In addition, solid content is weight% of the heating residue with respect to the total weight of a coating composition, and this heating is implemented at the temperature of 300 degreeC or more (generally 300 degreeC may be sufficient) in oxygen atmosphere.
When the hollow fine particles are hollow silica fine particles, the matrix forming material is a silicon compound, and the heating residue is formed from these two materials, the charged weight of the hollow fine particles and the weight of the matrix forming material in terms of the condensation compound (for example, tetra In the case of alkoxysilane, the solid content can be determined from the weight assuming that Si present is SiO ₂ and the weight in the case of trialkoxysilane being SiO _1.5 .

  Moreover, a leveling material and a viscosity modifier can also be added to the coating composition of this invention as needed.

  And the coating composition which concerns on this embodiment adds hollow silica type microparticles | fine-particles to matrix materials like the silicone resin-M mentioned above, and also adds the above other components as needed as needed. Can be obtained. At this time, in the coating composition, the weight ratio with the other solid content is not particularly limited, but the total solid content of the hollow silica-based fine particles and the matrix material / other solid content = 99/1 to 70 / It is preferable that it is the range of 30, and it is more preferable that it is 99/1-80/20. When there is more other solid content than 30, there exists a possibility that it may become difficult to obtain the mechanical strength of a film. The other solid content means an amount obtained by subtracting the solid content derived from the total solid content of the hollow silica fine particles and the matrix material from the solid content described above.

  In addition, the coating composition obtained as described above may be diluted with an organic solvent or water as necessary. In preparing the coating composition, the individual components may be preliminarily used as an organic solvent, It may be diluted with water or the like, and these can be called dilution thinner. Although it does not specifically limit as an organic solvent at the time of diluting, For example, lower aliphatic alcohols, such as methanol, ethanol, isopropanol (IPA), n-butanol, and isobutanol; Ethylene glycol, ethylene glycol monobutyl ether And ethylene glycol derivatives such as ethylene glycol monoethyl ether; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. One or two or more selected from the group consisting of these can be used. Further, in combination with these hydrophilic organic solvents, one or more of toluene, xylene, hexane, heptane ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, etc. can be used. .

  Then, the coating composition prepared as described above is applied to the surface of the substrate to form a coating film, and the coating film having a low refractive index can be obtained by drying the coating film. An article on which a film having a low refractive index is formed, that is, a coated article can be obtained. Thus, when forming a film, a film of a large area can be obtained more easily than a vapor phase method or a liquid phase method, and the film formation speed can be increased.

  The base material used for the front cover 4 or the like is not particularly limited. For example, inorganic base materials represented by glass, metal base materials, polycarbonate, polyethylene terephthalate, acrylic resins, fluororesins, The organic base material represented by acetylcellulose and a polyimide resin can be mentioned. Examples of the shape of the substrate include a plate shape and a film shape. Such a substrate may be used alone or may be a laminate of different materials. Furthermore, at least one or more layers may be formed in advance on the surface of the substrate. For example, as another layer, an ultraviolet curable hard coat layer, an electron beam curable hard coat layer, and a thermosetting hard coat layer may be mentioned. The material of the hard coat layer is roughly classified into an organic resin system mainly composed of acrylic resin and urethane resin and a silicone resin system. Further, an electromagnetic wave shielding function, an antistatic function, an infrared shielding function, and a color tone correction function can be imparted by adding the above-described antistatic agent, pigment, and the like to the hard coat layer. Furthermore, an AG (anti-glazing) function can be imparted by adding large particle (1 μm or more) particles in the hard coat layer. When the refractive index of the hard coat layer is increased, the difference in refractive index from the low refractive cured film formed thereon becomes larger, and lower reflectivity and higher transmittance can be achieved. It goes without saying that the same function can be imparted by adding an antistatic agent and a pigment to the base film.

Further, in the coating composition of the present invention, when silicone resin-M (particularly, a partial hydrolyzate or hydrolyzate of tetrafunctional alkoxysilane) is used as a matrix forming material, a silane coupling agent is formed in a layer immediately below the film. It is preferable to contain metal oxide (especially SiO ₂ ) fine particles in order to improve the adhesion to the cured film. Of course, it is needless to say that the adhesiveness is improved when the binder component of the layer located immediately below the coating is a silicone resin.

  Furthermore, by forming a high refractive index layer on the film formed by the coating composition of the present invention, an excellent reflection-increasing film (that is, a film having high light reflection) can be formed. A coating with the coating composition of the present invention and a high refractive layer (material limitation, no limitation on the formation method) are sequentially laminated on various reflector substrates to form a highly reflective film when the outermost surface becomes a high refractive layer.

  In addition, when the coating composition is applied to the surface of the base material, the surface of the base material is pre-washed so that the film is uniformly formed or the adhesion between the film and the base material is improved. It is preferable to leave. Examples of the pre-cleaning method include alkali cleaning, ammonium fluoride cleaning, plasma cleaning (including reduced pressure plasma and atmospheric pressure plasma), UV ozone cleaning, cerium oxide cleaning, and cleaning by corona discharge.

  In addition, the method for applying the coating composition to the surface of the substrate is not particularly limited. For example, brush coating, spray coating, dipping (dip coating), roll coating, gravure coating, micro gravure coating , Flow coat, curtain coat, knife coat, spin coat, table coat, sheet coat, single wafer coat, die coat, bar coat, reverse coat, cap coat, etc. A method or the like can be selected.

  It is preferable to heat-treat the coating formed on the surface of the substrate after drying. By this heat treatment, the mechanical strength of the coating can be further improved. The temperature during the heat treatment is not particularly limited. Throughout this specification, the coating after heat treatment is referred to as a “hardened coating” in the sense of a hardened coating.

In the coating composition of the present invention, a coating having a siloxane bond is formed by using a diluted thinner together with hollow fine particles and a matrix forming material, applying the coating composition to a substrate, forming a coating film, and drying. After that, it is possible to form a film substantially made of SiO ₂ (refractive index 1.47) by removing unnecessary substituents by heat treatment in an oxidizing atmosphere. In addition, the heat treatment improves the stability of the matrix, improves the mechanical strength, and can change the region where the substituent was present into a void. Furthermore, the final mechanical strength can be reached in a short time by heat treatment.

  Such a heat treatment requires that a certain silicon compound be treated at a high temperature of 300 ° C. or higher, and a heat treatment at a temperature lower than that causes unreacted groups such as alkoxide groups to remain in the cured film, resulting in a refractive index. May not be reduced to 1.47. However, with respect to another silicon compound as will be described later, for example, a very small number of groups remain even after a relatively low temperature heat treatment at 100 to 300 ° C., and a refractive index close to 1.47 or less, or 1.47 or less is achieved. It is possible.

  For example, when a film is formed using a coating composition using a silicone resin-M formed from a tetrafunctional alkoxy resin as a matrix-forming material, the film is formed at a low temperature, preferably 100 to 300 ° C., more preferably 50 to 150 ° C. Heat treatment for ~ 30 minutes. Even if the heat treatment is performed at such a low temperature, substantially the same mechanical strength as that in the case of performing the heat treatment at a high temperature can be obtained, and in this case, the formation cost of the film can be reduced. . Further, the type of the substrate is not limited as in the case of the heat treatment at a high temperature. In addition, for example, in the case of a glass substrate, since the thermal conductivity is low, it takes time for temperature rise and cooling, and the heat treatment at a high temperature slows down the processing speed, whereas the heat treatment at a low temperature conversely increases the processing speed. be able to.

  Therefore, if the coating composition according to the present embodiment is used, a film having a low refractive index can be easily formed. Depending on the type and amount of the material used, the refractive index of the film is 1.25 to 1.35 when the coating composition of the present invention is used.

  Moreover, it is preferable that the film thickness of the film formed on the surface of the substrate is in the range of 92 to 120 nm. In the case of performing an antireflection coating treatment in which a transmittance peak appears in the visible light curve region of 500 to 600 nm in the visible light wavelength range of 380 to 780 nm, the optical film thickness nd (n: refractive index, film thickness: d This is because the conditions under which) is a quarter of the peak wavelength (λ) are the best. When the film thickness is outside the above range, the peak shifts to the low wavelength side or the long wavelength side, and the antireflection effect decreases.

  Next, a second embodiment of the present invention will be described. The second embodiment is the same as the first embodiment except that the coating composition further includes a predetermined amount of a silane coupling agent. By including a silane coupling agent, when an antireflection coating is formed on a substrate using the coating composition of the present invention, adhesion between the substrate and the antireflection coating is improved. Further, it has an effect of imparting water repellency and slipping properties to the surface of a dry film, particularly a cured film. In order to impart slipping properties to the surface of a dry film, particularly a cured film, a particularly preferred silane coupling agent is a fluorine-containing one, so-called fluorine-based silane coupling agent (trialkoxyfluorosilane). Further, it is desirable to copolymerize the fluorine-based silane coupling agent in the coating composition with the matrix forming material.

Specific examples of preferred silane coupling agents (trialkoxyfluorosilane) include the following:

Next, a third embodiment of the present invention will be described. The third embodiment is the same as the second embodiment except that the coating composition further contains a predetermined amount of silicone oil. Particularly preferable silicone oil / R ₃ SiO— [R ₂ SiO] n—SiR ₃ for imparting slipping property to the surface of a dry film, particularly a cured film includes dimethyl silicone oil, phenylmethyl silicone oil, alkyl-modified Examples include silicone oil and fluorosilicone oil.

  According to the first to third embodiments, the refractive index and the film thickness of the antireflection coating are optimized, and the composition of the hollow fine particles / matrix forming material of the coating composition comprising the hollow fine particles and the matrix forming material is used. By optimizing the ratio and further adding trialkoxyfluorosilane and / or silicone oil as a slipping material component, it is possible to provide a lighting fixture lighting device that can withstand a practical level.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. The anti-reflective coating that can be formed by the coating composition of the present invention is highly effective in a single layer, but this coating composition is excellent in heat resistance and mechanical durability, and requires optical performance and hard coat function. It can also be applied to objects to be coated. For example, by coating the uppermost layer of a dielectric multilayer thin film (dichroic mirror) formed on a glass substrate, it suppresses the moisture absorption of the dielectric thin film without impairing the optical properties, thus suppressing the refractive index fluctuation due to moisture absorption. I can do it. Further, for example, in the case of an ultraviolet cut filter in which zinc oxide (ZnO), which is an amphoteric oxide, is formed on a glass substrate, antireflection coatings 5a and 5b are formed on both sides of the glass substrate 4 as shown in FIG. Thus, it is possible to prevent corrosion deterioration of the ZnO film 8 and to provide an anti-corrosion film plus an antireflection effect. In addition, it is possible to provide a dichroic mirror and a high-performance UV cut filter that have both a hard coat function and a moisture-proof coat and that do not change in color temperature due to turning on and off.

  The lighting device means a device including at least a light source and a translucent member. For example, a fluorescent lamp, an electrodeless discharge lamp, a mercury lamp, a halogen bulb with a reflector, a base light, a spotlight, a road light, a guide light In addition, a liquid crystal projection light source unit, a projector, and the like are included. In addition, the translucent member includes a lamp bulb, a front cover that covers the front of the light source, a cold mirror, various optical filters, a lens, a reflecting member that controls light from the lamp, or a member that guides the lamp light (fiber, light guide). Light plate). In addition, as a reflecting member, a high-purity aluminum material is shaped into a predetermined shape, then electrolytically or chemically polished, and a rust-proof coating (alumite, transparent coating) is applied thereon, or a functional resin After coating the surface of a base material shaped into a predetermined shape with metal, glass, ceramic, and coating a bright metal such as aluminum, silver, silver alloy by PVD method, and a high refractive index substance Examples thereof include an optical multilayer thin film (dichroic mirror) in which low refractive index substances are alternately laminated.

  Hereinafter, the present invention will be specifically described by way of examples. Unless otherwise specified, all “parts” represent “parts by weight”, and “%” represents “% by weight” except for the total light transmittance, reflectance, and haze ratio described later.

Add 356 parts of methanol to 208 parts of tetraethoxysilane, add 18 parts of water and 18 parts of 0.01N hydrochloric acid aqueous solution (“H ₂ O” / “OR” = 0.5), and use a disper. Mixing was performed to obtain a mixed solution. This mixed solution was stirred in a thermostatic bath at 25 ° C. for 2 hours to obtain silicone resin-M (A) having a weight average molecular weight adjusted to 850 as a matrix forming material.

  Next, hollow silica IPA (isopropanol) dispersion sol (solid content 20% by weight, average primary particle diameter of about 35 nm, outer shell thickness of about 8 nm, manufactured by Catalyst Kasei Kogyo Co., Ltd.) is used as a hollow silica-based fine particle. In addition to (A), hollow silica-based fine particles / silicone resin-M (condensation compound equivalent) is blended so that the weight ratio is 70/30 on a solid basis, and then the total solid content is 1%. The coating composition of the present invention was prepared by diluting with methanol.

  This coating composition was allowed to stand for 1 hour and then polished and washed in advance with cerium oxide fine particles (thickness 1 mm, top surface (surface not in contact with molten tin by float method, refractive index: 1.54)) After coating with a wire bar coater to form a coating film with a thickness of about 100 nm, and leaving to dry for 1 hour to obtain a coating film, the coating film was heat treated at 200 ° C. for 10 minutes in an oxygen atmosphere. Thus, a cured film was obtained.

  In Example 1, the coating composition was prepared in the same manner as in Example 1 except that the hollow silica-based fine particles / silicone resin-M (condensed compound equivalent) was blended so that the weight ratio was 40/60 based on the solid content. Prepared. Then, this coating composition was applied and dried in the same manner as in Example 1, followed by heat treatment to obtain a cured film.

  In Example 1, hollow silica-based fine particles / silicone resin-M (condensed compound equivalent) was blended so that the weight ratio was 70/30 on a solid basis, and trimethylalkoxypropylfluorosilane was added on a solid basis. A coating composition was prepared in the same manner as in Example 1 except that% was added. Then, this coating composition was applied and dried in the same manner as in Example 1, followed by heat treatment to obtain a cured film.

  In Example 3, a coating composition was prepared in the same manner as in Example 3 except that 1% of dimethyl silicone oil was added based on the solid content. And this coating composition was apply | coated similarly to Example 1, it dried, and the cured film was obtained by heat-processing after that.

<Comparative example 1>
In Example 1, the coating composition was prepared in the same manner as in Example 1 except that the hollow silica-based fine particles / silicone resin-M (condensed compound equivalent) was blended so that the weight ratio was 80/20 based on the solid content. Prepared. Then, this coating composition was applied and dried in the same manner as in Example 1, followed by heat treatment to obtain a cured film.

<Comparative example 2>
In Example 1, the coating composition was prepared in the same manner as in Example 1 except that the hollow silica-based fine particles / silicone resin-M (condensed compound equivalent) was blended so that the weight ratio was 30/70 based on the solid content. Prepared. Then, this coating composition was applied and dried in the same manner as in Example 1, followed by heat treatment to obtain a cured film.

Table 1 shows the blending ratios of Examples 1 to 4 and Comparative Examples 1 and 2.

  For the cured coatings obtained in Examples 1 to 4 and Comparative Examples 1 and 2, total light transmittance, reflectance, haze ratio, refractive index and mechanical strength were measured, and performance evaluation of the cured coating was performed. Went. In the total light transmittance evaluation test, the total light transmittance at a wavelength of 555 nm was measured using a spectrophotometer (“U-4000” manufactured by Hitachi, Ltd.). In the reflectance evaluation test, the reflectance at a wavelength of 555 nm was measured using a spectrophotometer (“U-4000” manufactured by Hitachi, Ltd.). In the haze rate evaluation test, a haze meter (“NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.) was used for measurement. In the refractive index evaluation test, the glass fracture surface was observed with a scanning electron microscope, the film thickness of the cured film was measured, and then derived with an ellipsometer ("EMS-1" manufactured by ULVAC). In the mechanical strength evaluation test, the surface of the cured coating was rubbed with steel wool # 0000, and the mechanical strength was determined based on the level of scratches generated in the cured coating.

The results of the evaluation test are shown in Table 2. In the evaluation results of the mechanical strength, “A” does not generate scratches, “B” generates slight scratches, “C” generates scratches, and “D” generates many scratches (whitening) Or peeling). As shown in Table 2, Examples 1 to 4 in which the present invention is implemented have antireflection characteristics and mechanical durability as compared with Comparative Examples 1 and 2, and are used as lighting fixtures. The results satisfying the required practical level were obtained.

  Next, an embodiment in which the present invention is applied to a dichroic mirror or an ultraviolet cut filter will be described in comparison with a case where the present invention is not applied.

Immediately after the manufacture of a dichroic mirror in which 20 layers of TiO ₂ / MgF ₂ are alternately laminated on the inner surface of a parabolic mini-halogen spotlight reflector (Matsushita Electric Works, Ltd. NK01943) formed by melting press of borosilicate glass On the top of the optical multilayer thin film of the product, the same coating composition as in Example 1 was coated by dipping (dip) coating to form an antireflective coating with an average thickness of 110 nm, and a product without an antireflective coating was prepared. .

  As for the products without and with anti-reflection coating, the spectral transmission characteristics immediately after production were measured with a spectrophotometer U4000 manufactured by Hitachi Ltd. There was no change in the product, but the product in which the antireflection coating was not formed shifted the characteristics to the 20 nm short wavelength side.

About the ultraviolet cut filter described in JP-A-01-245201, as a protective film after the formation of zinc oxide (ZnO), the same coating composition as in Example 1 is coated on both sides by dipping (dipping) coating. An ultraviolet cut filter was obtained.

As a result of measuring the transmission characteristics of this filter, the transmittance increased by 6% at 555 nm as compared with the SiO ₂ protective film. Moreover, as a result of being immersed in a 1% solution of Na ₂ CO _{3 and} a 1% solution of H ₂ SO ₄ for 4 hours, there was no corrosion of ZnO.

The sectional side view of the illuminating device by one Embodiment of this invention. (A) is sectional drawing of the front cover of the illuminating device, (b) is sectional drawing of a hollow microparticle. Sectional drawing of the translucent member which shows the modification of the same illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Lamp bulb 3 Light source 4 Front cover (translucent member)
5 Anti-reflective coating 6 Hollow fine particles 7 Matrix

Claims (6)

A light source and a translucent member that is disposed at a position facing the light source and transmits light emitted from the light source;
An antireflection coating for antireflection of visible light is formed by coating the light incident side surface of the translucent member with a coating composition containing a hollow fine particle and a matrix forming material that forms a porous matrix. A lighting device formed of
The lighting apparatus according to claim 1, wherein a refractive index of the antireflection coating is 1.25 to 1.35.   The lighting device according to claim 1, wherein the antireflection coating is a single layer film and has a thickness of 92 to 120 nm. The hollow fine particles are silica-based inorganic oxides,
The matrix forming material is a silicon compound having a siloxane bond, or a silicon compound capable of providing a siloxane bond in the process of forming the antireflection coating,
The lighting device according to claim 1, wherein the coating composition has a weight ratio of the hollow fine particles to the matrix forming material of 40/60 to 70/30.   In the coating composition, 5 to 20% by weight of trialkoxyfluorosilane is mixed with the total weight of the active ingredients of the hollow fine particles and the matrix-forming material, and the trialkoxyfluorosilane and the matrix are mixed. The lighting device according to claim 3, wherein the forming material is copolymerized.   The said coating composition is 0.1-10 weight% of silicone oils with respect to the total weight of the active ingredient amount of the said hollow microparticles and the said matrix formation material, It is characterized by the above-mentioned. Lighting device. The light incident side of the light transmissive member is coated by coating the light incident side surface and the light output side surface of the light transmissive member with the coating composition according to claim 3. A lighting device, wherein a single-layer antireflection coating having a film thickness of 92 to 120 nm is formed on the surface and the light emitting side surface.

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