JP5642535B2 - Novel silica-based hollow fine particles, base material with transparent film, and paint for forming transparent film - Google Patents

Description

  The present invention relates to novel silica-based hollow fine particles having protrusions on the surface of spherical particles, a coating for forming a transparent film using the fine particles, and a substrate with a transparent film. More specifically, since it has protrusions of a predetermined size on the surface of the spherical silica-based hollow fine particles, it should be suitably used for forming a transparent film excellent in antireflection performance with improved strength, scratch resistance, alkali resistance, etc. The present invention relates to a novel silica-based hollow fine particle, a coating for forming a transparent film using the fine particle, and a substrate with a transparent film.

  Conventionally, in order to prevent reflection of the surface of a substrate such as glass, plastic sheet, plastic lens, etc., it is known to form an antireflection film on the surface, for example, by coating method, vapor deposition method, CVD method, etc. A coating of a low refractive index substance such as fluororesin or magnesium fluoride is formed on the surface of a glass or plastic substrate, or a coating liquid containing low refractive index fine particles such as silica fine particles is applied to the surface of the substrate. A method of forming an antireflection coating is known (see, for example, Patent Document 1; Japanese Patent Laid-Open No. 7-133105). At this time, in order to improve the antireflection performance, it is also known to form a high refractive index film containing fine particles of high refractive index under the antireflection coating.

  The applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 2001-23611 (Patent Document 2) is a method for producing silica-based fine particles having cavities therein and the resulting silica-based fine particles have a low refractive index and are formed using the silica-based fine particles. It is disclosed that the transparent film has a low refractive index and excellent antireflection performance.

  Furthermore, Japanese Patent Application Laid-Open No. 2002-79616 (Patent Document 3) discloses that when such a transparent film is formed and used on the front surface of a display device, the antireflection performance is excellent and the display performance is improved.

  However, although conventional transparent coatings using silica-based fine particles are excellent in antireflection performance, further improvements in strength, scratch resistance and the like are required.

JP-A-7-133105 JP 2001-23611 A JP 2002-79616 A

  As a result of intensive studies, the present inventors prepared conventional spherical silica-based hollow fine particles, and then surface-treated to contain a small amount of alumina, and ion-exchange the water glass solution in the presence of the water glass solution. It was found that when an acidic silicic acid solution obtained by dealkalization with a resin was added, deformed silica-based hollow fine particles having protrusions on the surface of spherical silica-based hollow fine particles were obtained, and when this was used, the scratch resistance was greatly improved. The inventors have found that a transparent film can be formed and have completed the present invention.

[1] The average particle diameter (D _P ) is in the range of 25 to 200 nm, has a convex portion on the surface, and the average diameter (convex _P ) of the bottom surface portion of the convex portion is 1 of the average particle diameter (D _P ). The average particle size is determined by measuring the longest diameter (D _L ) and the diameter (D _S ) perpendicular to the longest diameter for any 20 particles. (D _L ) + (D _S ) and the average value thereof) Silica-based hollow fine particles.
[2] The silica-based hollow fine particles according to [1], wherein the height of the convex portion (convex _{H 2} ) is in the range of 1/10 to 1/1 of the average diameter (convex _{P 2} ) of the bottom surface portion of the convex portion.
[3] The silica-based hollow fine particles of [1] or [2] having a refractive index in the range of 1.10 to 1.35.
[4] A paint for forming a transparent film, comprising [1] to [3] silica-based hollow fine particles, a matrix component, and a polar solvent.
[5] The concentration of the silica-based hollow fine particles in the paint is in the range of 0.2 to 40% by weight as the solid content, the concentration of the matrix component is in the range of 0.2 to 40% by weight as the solid content, and the total solid content concentration The paint for forming a transparent film according to [4], wherein is in the range of 1.0 to 50% by weight.
[6] The transparent film-forming paint according to [4] or [5], wherein the matrix-forming component is an ultraviolet curable resin.
[7] A substrate with a transparent coating, which has a transparent coating formed on the substrate by using the transparent coating-forming paint according to [4] to [6].
[8] The substrate with a transparent coating according to [7], wherein the content of the silica-based hollow fine particles in the transparent coating is 20 to 80% by weight.
[9] The substrate with a transparent coating according to [7] or [8], wherein the transparent coating has a thickness of 30 to 300 nm and a refractive index in the range of 1.20 to 1.50.

  In addition, the present applicant proposes a method for producing fried sugar-like silica particles in JP-A-2009-78936, JP-A-2009-78935, JP-A-2009-91197, and JP-A-2010-24119. doing. However, these prior applications have a refractive index as high as about 1.45 and insufficient antireflection performance, and the bonding effect with the particles with the matrix resin is not always sufficient, and the scratch resistance is insufficient. there were.

  According to the present invention, since projections of a predetermined size are formed on the surface of the spherical silica-based hollow fine particles, formation of a transparent film excellent in strength, scratch resistance, alkali resistance, etc. by using such fine particles can do.

The model figure of the cross section of the novel silica type hollow microparticle of this invention is shown. The electron microscope (TEM) photograph of the novel silica type hollow microparticles of the present invention is shown.

Hereinafter, first, the novel silica-based hollow fine particles according to the present invention will be specifically described.
[New silica-based hollow fine particles]
The novel silica-based hollow fine particles according to the present invention have convex portions on the surface.

The convex portion is formed in a state in which the spherical surface of the bowl-shaped particles obtained by cutting the spherical silica fine particles approximately in half is removed and the cut surface is joined to the surface of the spherical silica-based hollow fine particles.
The average diameter (convex _P ) of the bottom surface of the convex part is in the range of 1/40 to 1/2, more preferably 1/10 to 1 / 2.5 of the average particle diameter (D _P ) of the novel silica-based hollow fine particles. Preferably there is.

Here, (convex _{P 2} ) corresponds to the diameter of the cut surface of the bowl-shaped particle.
If the (protrusion _P ) is too small relative to the silica-based hollow fine particles, the convex portions are too small to substantially change substantially from the spherical silica-based hollow fine particles without the convex portions. The effect of improving the scratch resistance, strength, alkali resistance, etc. of the transparent film may be insufficient. On the other hand, it is difficult to form a protrusion having a large (convex _P ) exceeding the upper limit of the above range, and even if it is obtained, it becomes difficult to densely fill the transparent film with such a protrusion. In some cases, the haze is deteriorated, the refractive index is not sufficiently lowered, and the antireflection performance is insufficient.

The height of the convex portion (convex _{H 2} ) is preferably in the range of 1/10 to 1/1, more preferably 2/10 to 8/10, of the average diameter (convex _{P 2} ) of the convex portion.
If the height of the convex portion (convex _H ) is small, the bonding area with the matrix component is small, the anchoring effect is insufficient, and the effect of improving the scratch resistance, strength, alkali resistance, etc. of the transparent coating is insufficient. There is a case. Even if the height (convex _H ) is too high, it is difficult to obtain one that exceeds the above upper limit, and even if it is obtained, the convex portion inhibits dense packing of the novel silica-based hollow fine particles in the transparent film, In some cases, the haze and transmittance of the transparent coating are insufficient, and the refractive index is not sufficiently lowered, so that the antireflection performance is insufficient.

The average particle diameter (D _P ) of such novel silica-based hollow fine particles having convex portions on the surface is preferably in the range of 25 to 200 nm, more preferably 30 to 80 nm. (This is the final particle size, and _Dp is the diameter including the convex portion of the silica-based hollow particle surface)
The shape of the novel fine particles of the present invention is a shape in which a plurality of convex portions are formed on the surface of the hollow particles.

When the average particle diameter (D _P ) of the novel silica-based hollow fine particles is small, it is difficult to form convex portions on the surface, and even if obtained, the hollow ratio is low, but the refractive index is insufficient. It becomes. When the average particle diameter (D _P ) of the novel silica-based hollow fine particles is large, the transparency is lowered, and when exceeding the film thickness of the transparent coating, there is a problem that the film strength, scratch resistance and alkali resistance are lowered.

  The refractive index of the novel silica-based hollow fine particles according to the present invention is preferably in the range of 1.10 to 1.35, more preferably 1.10 to 1.30. Although the refractive index of the novel silica-based hollow fine particles depends on the ratio of the hollow part and the surface convex part, it is difficult to obtain a refractive index of less than 1.10, and if it exceeds 1.35, the content of the particles, Depending on the size, the antireflection performance may be insufficient.

FIGS. 1 and 2 show a cross-sectional model view and an electron microscope (TEM) photograph of such a novel silica-based hollow fine particle of the present invention. As shown in FIG. 2, the hollow portion is lightly shaded.
The average particle diameter (D _P ), the size of the convex portion (convex _{P 2} ), and the height of the convex portion (convex _{H 2} ) were determined by taking a transmission electron micrograph of the novel silica-based hollow fine particles.

The average particle diameter (D _P ) is determined by measuring the longest diameter (D _L ) and the diameter (D _S ) perpendicular to the longest diameter for any 20 particles, and the particle diameter is (D _L ) + (D _S ) The average value was taken as 1/2.
The average diameter (convex _P ) of the convex portion was determined by measuring the diameter of the lowest portion of the convex portion, and taking the average value.
The height of the convex portion (convex _{H 2} ) was obtained by measuring the height of the peripheral portion of the particle and taking the average value.

The refractive index of the novel silica-based hollow fine particles is measured by the following method.
(1) The composite oxide dispersion is taken in an evaporator and the dispersion medium is evaporated.
(2) This is dried at 120 ° C. to obtain a powder.
(3) A standard refraction liquid having a known refractive index is dropped on a glass plate of a few drops, and the above powder is mixed therewith.
(4) The operation of (3) is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is used as the refractive index of the fine particles.

  The hollow part is filled with a gas or a solvent depending on the surrounding environment, and the hollow part forms a hollow structure inside the particle like a ball, but the hollow part has one chamber in the particle. However, there may be two or more plural chambers.

  The void ratio of the hollow portion is usually in the range of 20% by volume to 80% by volume, and the measurement of the hollow portion is performed by setting the cavity to air (refractive index = 1.0) from the actually measured refractive index, and The shell layer is obtained by calculation with silica (refractive index = 1.45).

Production method The production method of such a novel silica-based hollow fine particle is not particularly limited as long as a novel silica-based hollow fine particle having the above-described convex portions and having an average particle diameter and a refractive index within the above range is obtained. The exemplified method can be suitably employed.

(i) Silica-based hollow fine particles First, silica-based hollow fine particles serving as a base for forming convex portions are produced. A method for producing silica-based hollow fine particles is disclosed in Japanese Patent Application Laid-Open No. 2001-233611, filed by the present applicant. , JP 2004-203683 A, JP 2006-21938 A, WO 2006/009132 and the like.

  Specifically, the composite oxide fine particles composed of silica and an inorganic oxide other than silica are used as a core, and after forming the silica coating layer (1) as necessary, the inorganic oxide other than silica is removed, It can be obtained by forming the silica coating layer (2) as necessary and hydrothermally treating at a high temperature as necessary. The silica-based hollow fine particles are formed so that the total thickness of the silica coating layer (1) and the silica coating layer (2) is about 1 to 10 nm on the core particles having an average particle diameter of about 20 to 190 nm. It can be obtained by forming a silica coating layer.

The method described above is an example, and the present invention is not limited to these methods.
In the present invention, particles having an average particle diameter of about 20 to 200 nm, preferably 25 to 75 nm are used as silica-based hollow fine particles. (Before formation of convex part)
The thickness of the silica coating layer varies depending on the particle diameter, but is in the range of 1 to 20 nm, and the porosity is generally in the range of 20% by volume to 80% by volume.

(ii) Addition of alkali aluminate aqueous solution First, an aqueous dispersion of silica-based hollow fine particles having a solid concentration of 1 to 20% by weight is prepared, and an aqueous alkali aluminate solution is mixed therewith. At this time, the addition amount of the alkali aluminate aqueous solution varies depending on the average particle diameter of the silica-based hollow fine particles, but is 0.01 to 10% by weight, preferably 0, of the solid content weight of the silica-based hollow fine particles as Al ₂ O _3. .1 to 0.5% by weight.

  If the mixing amount of the alkali aluminate aqueous solution is within the above range, an alumina-modified silica-based hollow microparticle having alumina formed on the surface as a base for forming a convex portion by adding an acidic silicic acid solution described later is prepared. Can do.

When the amount of the alkali aluminate aqueous solution added is less than 0.01% by weight of the solid content of the silica-based hollow fine particles as Al ₂ O ₃ , the number of convex portions is too small or the convex portions Is too large, the improvement in film strength, scratch resistance and alkali resistance may be insufficient or may be reduced.

When the amount of the alkali aluminate aqueous solution exceeds 10% by weight, the surface of the silica-based hollow fine particles is covered with Al ₂ O ₃ , and it becomes difficult to form protrusions when the acidic silicic acid solution is added. It may become coated particles.

At this time, the addition rate varies depending on the average particle diameter, the addition amount, and the like of the silica-based hollow fine particles, but it is preferable to add gradually. When added rapidly, Al ₂ O ₃ (alumina hydrate) fine particles adsorb on the surface of the silica-based hollow fine particles and may form Al ₂ O ₃ (alumina hydrate) particles in the liquid without adsorbing. . Next, the dispersion is heated to 40 to 150 ° C. and aged with stirring for about 3 to 12 hours.

By stirring and aging under the above-mentioned heating, the surface of the silica-based hollow fine particles is doped with Al serving as an alumina base for forming convex portions (a form in which Si atoms and Al atoms are substituted) or Al ₂ O ₃ (alumina hydrate) ) Silica-based hollow fine particles with adsorbed fine particles can be obtained.

(iii) Addition of alkali silicate aqueous solution Next, an alkali silicate aqueous solution is added. The addition amount of the alkali silicate has an average particle size of the silica-based hollow particles, the varies of alumina added amount of alkali aluminate solution, 0.1 to 30 wt% of the solid weight of the silica-based hollow fine particles as SiO _2, preferably Is in the range of 1 to 10% by weight. When the aqueous alkali silicate solution is added, the pH of the silica-based hollow fine particle dispersion becomes alkaline, and dissolved silica is present in the dispersion. Therefore, when the acidic silicate liquid described later is added, It is considered that precipitation of silica is promoted.

When the addition amount of the aqueous alkali silicate solution is small, even if an acidic silicate solution described later is added, it may not be possible to form a projection having a desired projection size and height corresponding to the addition amount. If the amount of the alkali silicate aqueous solution added is too large, the reason is not clear, but it may not be possible to form a protrusion having a desired protrusion size and height.
When an aqueous alkali silicate solution is added within the above range, a desired convex portion can be formed by depositing silica on the alumina base by adding an acidic silicic acid solution described later.

(iv) Addition of acidic silicic acid solution Next, the dispersion to which the aqueous alkali silicate solution has been added is heated to 40 to 150 ° C, and the acidic silicic acid solution is added. Thereby, the silica in the acidic silicic acid solution is deposited on the alumina base on the surface of the hollow particles to form a convex portion.

The addition amount of the acidic silicic acid solution, the average particle size of the silica-based hollow particles, the varies of alumina added amount of alkali aluminate solution, 1 to 100 wt% of the solid weight of the silica-based hollow fine particles as SiO _2, preferably Is in the range of 10-80% by weight.

When the amount of the acidic silicic acid solution is small, the size of the convex portion (convex _P ) formed is too small, or the height of the convex portion (convex _H ) is too low. The scratch resistance, alkali resistance, etc. may be insufficient. Even if the amount of acidic silicic acid solution is too large, silica is deposited between the projections once formed and the projections are flattened, resulting in insufficient film strength, scratch resistance, alkali resistance, etc. Or the antireflective performance may be insufficient due to a decrease in the refractive index of the particles.

  The addition rate of the acidic silicic acid solution varies depending on the average particle diameter, addition amount, etc. of the silica-based hollow fine particles, but it is preferable to add gradually. When added rapidly, new silica fine particles that are not involved in the formation and growth of the convex portions may be by-produced, and in some cases, particles having a flat convex portion may be finally obtained.

Next, a novel silica-based hollow fine particle dispersion can be produced by deionization with an ion exchange resin or washing with an ultrafiltration membrane or the like.
The novel silica-based hollow fine particle dispersion can also be used after solvent substitution with an organic solvent such as alcohol.

Surface treatment Furthermore, it can be used after being treated with a silane coupling agent or the like by a conventionally known method.
Specifically, the novel silica-based hollow fine particles of the present invention are preferably surface-treated with an organosilicon compound represented by the following formula (1) and a hydrolyzate thereof.

_{R n -SiX 4-n (1} )
(In the formula, R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. X: an alkoxy group having 1 to 4 carbon atoms or a silanol group) , Halogen, hydrogen, n: an integer of 0 to 3)

  Examples of the organosilicon compound represented by the formula (1) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane. , Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane, 3,3,3- Trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxymethyltrimethoxy Silane, γ-glycidoxymethyltriexisilane, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- (β-glycidoxyethoxy) propyltrimethoxysilane, γ- (meth) acrylooxymethyltrimethoxysilane, γ- (meth) acrylooxymethyltriethoxysilane, γ- (meth) acrylooxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acrylooxypropyltrimethoxy Silane, γ- (meth) acrylooxypropyltrimethoxysilane, γ- (meth) a Acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, butyltrimethoxysilane, isobutyltriethoxysilane, hexyltriethoxysilaoctyltriethoxysilane, decyltriethoxysilane, butyltriethoxysilane, isobutyl Triethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, 3-ureidoisopropylpropyltriethoxysilane, perfluorooctylethyltrimethoxysilane, perfluorooctylethyltriethoxysilane, perfluorooctylethyltriiso Propoxysilane, trifluoropropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β ( Minoechiru) .gamma.-aminopropyltrimethoxysilane, N- phenyl--γ- aminopropyltrimethoxysilane, .gamma.-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, and the like.

When the surface treatment is performed with such an organosilicon compound, it can be uniformly dispersed in the matrix and densely filled, and a transparent film excellent in film strength and scratch resistance can be obtained.
The surface treatment of the novel silica-based hollow fine particles is carried out by adding a predetermined amount of the above organosilicon compound to an alcohol dispersion of fine particles, adding water thereto, and adding an acid or alkali as a hydrolysis catalyst as necessary to hydrolyze the organosilicon compound. Decompose.

  The amount ratio of the new silica-based hollow fine particles to the organosilicon compound (weight as the solid content of the organosilicon compound / weight of the new silica-based hollow fine particles) varies depending on the average particle size of the new silica-based hollow fine particles. 0.005 to 1.0, more preferably 0.01 to 0.3.

When the weight ratio is low, the affinity with the matrix-forming component described later is low, the dispersibility and stability in the paint are insufficient, and the fine particles may aggregate in the paint. May not be obtained, and adhesion to the substrate, film strength, scratch resistance, etc. may be insufficient. Even if the weight ratio is too high, the dispersibility in the paint is not further improved, the refractive index of the novel silica-based hollow fine particles is increased, and a transparent film having a desired low refractive index may not be obtained. The antireflection performance may be insufficient.
Next, the transparent film-coated substrate according to the present invention will be specifically described.

[Base material with transparent coating]
The substrate with a transparent coating according to the present invention is a substrate with a transparent coating in which a transparent coating composed of a novel silica-based hollow fine particle and a matrix component is formed on the substrate, and the average of the novel silica-based hollow fine particle The particle diameter (D _P ) is in the range of 30 to 200 nm, the surface has a convex portion, and the average diameter (convex _P ) of the bottom surface of the convex portion is 1/40 to 1/1 / of the average particle diameter (D _P ). 2 and the refractive index is in the range of 1.10 to 1.35.

As the base material , a conventionally known base material can be used. In addition to glass, cellulose base materials such as triacetyl cellulose film (TAC), diacetyl cellulose film, acetate butyrate cellulose film, polyethylene terephthalate (PET) ), Polyester base materials such as polyethylene naphthalate, polyolefin base materials such as polyethylene film, polypropylene film and cyclic polyolefin film, polyamide base materials such as nylon-6, nylon-66, polyacrylic film, polyurethane film , Polycarbonate film, polyether film, polyethersulfone film, polystyrene film, polymethylpentene film, polyetherketone film, acrylonitrile film, etc. And the like. In addition, a coated substrate in which another coating such as a hard coat film is formed on such a substrate can also be used.

As the novel silica-based hollow fine particles constituting the transparent coating transparent coating, the silica-based hollow fine particles having convex portions on the surface are used.
The content of the novel silica-based hollow fine particles in the transparent film is preferably in the range of 20 to 80% by weight, more preferably 30 to 60% by weight.

  If there are few new silica-based hollow microparticles in the transparent coating, a transparent coating with a sufficiently low refractive index may not be obtained, and there will be too much new silica-based hollow microparticles in the transparent coating. Since the amount is small, the strength, scratch resistance, alkali resistance, etc. of the transparent film may be insufficient.

  As the matrix component, a silicone matrix component, an organic resin matrix component, or the like is used. As the silicone matrix component, a hydrolyzed polycondensate of an organosilicon compound similar to the formula (1) is preferably used, and may be a sol-gel matrix.

Examples of the organic resin matrix component include known thermosetting resins, thermoplastic resins, electron beam curable resins, and ultraviolet curable resins as coating resins.
Examples of such resins include conventionally used thermoplastic resins such as polyester resins, polycarbonate resins, polyamide resins, polyphenylene oxide resins, thermoplastic acrylic resins, vinyl chloride resins, fluororesins, vinyl acetate resins, and silicone rubbers. , Urethane resin, melamine resin, silicon resin, butyral resin, reactive silicone resin, phenol resin, epoxy resin, unsaturated polyester resin, thermosetting acrylic resin, UV curable acrylic resin, etc., UV curable type An acrylic resin etc. are mentioned. Further, it may be a copolymer or modified body of two or more of these resins. These resins may be emulsion resins, water-soluble resins, and hydrophilic resins. Further, in the case of a thermosetting resin, it may be an ultraviolet curable type or an electron beam curable type, and in the case of a thermosetting resin, a curing catalyst may be included.

In the present invention, among them, an ultraviolet curable resin or an electron beam curable resin is preferable, and an ultraviolet curable resin is particularly preferable.
The content of the matrix component in the transparent coating is preferably in the range of 20 to 80% by weight, more preferably 40 to 70% by weight.

  If the matrix component in the transparent film is small, the matrix component is small, resulting in insufficient adhesion to the substrate, and it is difficult to obtain a transparent film excellent in scratch resistance, strength, alkali resistance, etc. Further, the haze of the transparent film may be increased. On the other hand, even if there are too many matrix components in the transparent film, a transparent film having a sufficiently low refractive index may not be obtained.

  The film thickness of the transparent coating is preferably in the range of 30 nm to 300 nm, more preferably 70 to 200 nm. When the film thickness of the transparent film is thin, the optical film thickness deviates from the Fresnel principle, and sufficient antireflection performance may not be obtained. If the film thickness of the transparent coating is too thick, cracks may occur in the film or the strength of the film may be reduced, and the film may be too thick and the antireflection performance may be insufficient.

  Moreover, it is preferable that the refractive index of a transparent film exists in the range of 1.20-1.50, Furthermore, 1.20-1.35. By using the particles, a transparent film having a low refractive index in such a range and high antireflection performance can be formed.

The refractive index of the transparent coating of the present invention was measured with an ellipsometer (ULVAC, EMS-1).
A conventionally well-known method is employable as a formation method of such a base material with a transparent film.

  Specifically, a transparent film can be formed by applying a transparent film-forming coating composition according to the present invention, which will be described later, to a substrate by a well-known method, drying, and curing by a conventional method such as ultraviolet irradiation or heat treatment. it can.

  In addition, the base material with a transparent film of the present invention can be provided with a conventionally known thin film such as a primer film, a high refractive index film, and a conductive film together with the transparent film. At this time, the provision of a primer film improves impact resistance, adhesion to the substrate, etc., the provision of a high refractive index film further improves the antireflection performance, and the provision of a conductive film provides antistatic performance and electromagnetic waves. A substrate with a transparent coating having shielding ability and the like is obtained.

[Transparent coating paint]
Next, the transparent film forming paint according to the present invention will be described.
The transparent film-forming paint according to the present invention is characterized by comprising the novel silica-based hollow fine particles, a matrix-forming component, and a polar solvent.

  The concentration of the novel silica-based hollow fine particles in the paint is preferably in the range of 0.2 to 40% by weight, more preferably 0.3 to 35% by weight as the solid content. When there are few new silica type hollow microparticles in a coating material, the content of the new silica type hollow microparticles in the obtained transparent film is small, and a transparent film having a sufficiently low refractive index may not be obtained. Even if there are too many novel silica-based hollow fine particles in the paint, the stability of the paint may be insufficient, and the adhesiveness, strength, etc. of the resulting transparent film may be reduced.

  As the matrix-forming component, as described above, a silicone-based (including sol-gel-based) matrix component, an organic resin-based matrix-forming component, or the like is used. The matrix-forming component is a precursor of the matrix component, and in the case of a silicone-based matrix component, the same organosilicon compound and hydrolyzed polycondensate as in the formula (1) are used. In addition, as the organic resin matrix forming component, in the case of a thermoplastic resin, the matrix component and the matrix forming component are the same, and in the case of a thermosetting resin and an electron beam curable resin, it is a monomer before the reaction. Accordingly, a catalyst, a curing accelerator, a curing aid, a sensitizer, and the like may be included.

  In the present invention, among them, an ultraviolet curable resin or an electron beam curable resin is preferable, and an ultraviolet curable resin is particularly preferable. When such an ultraviolet curable resin is used, a transparent film excellent in scratch resistance, hardness, and the like can be produced in a short time.

The concentration of the matrix-forming component in the paint as a solid content is preferably 0.2 to 40% by weight, more preferably 0.3 to 30% by weight.
If there are few matrix forming components in the paint, the film strength, abrasion resistance, etc. of the obtained transparent film may be insufficient, and a transparent film having a sufficient film thickness may not be obtained.

  In addition, a transparent film having a sufficient film thickness may not be obtained. Even if there are too many matrix-forming components in the paint, the stability of the paint may be reduced, and adhesion to the substrate, film strength, scratch resistance, etc. may be reduced.

Polar Solvent The polar solvent used in the present invention is not particularly limited as long as it can dissolve or disperse the matrix-forming component and, if necessary, the polymerization initiator, and can uniformly disperse the novel silica-based hollow fine particles. Can be used.

  Specifically, alcohols such as water, methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol; acetic acid Esters such as methyl ester, ethyl acetate, butyl acetate; ethers such as diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether Acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetone Ketones such as acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, toluene, cyclohexanone, isophorone and the like.

  Among them, alcohols and carbonyl group-containing solvents are uniformly dispersed with the surface-treated new silica-based hollow fine particles, and the stability of the paint is excellent, the coating property is excellent, the uniformity, the adhesion to the substrate, and the strength. It is possible to form a transparent film with excellent reproducibility.

  The concentration of the coating for forming a transparent film comprising the above-described components is preferably in the range of 1 to 50% by weight, more preferably 2 to 40% by weight as the total solid content. If the total solid content concentration is low, the film thickness of the transparent film may be less than 30 nm, and sufficient film strength and antireflection performance may not be obtained. Even if the total solid content is too much, the viscosity of the paint is increased, so that the applicability may be lowered or the stability of the paint may be insufficient. The film strength, scratch resistance, etc. may be insufficient.

A conventionally well-known method can be employ | adopted as a method of forming a transparent film using the coating material for transparent film formation which concerns on this invention.
Specifically, known methods such as the dipping method, spray method, spinner method, roll coating method, bar coating method, slit coater printing method, gravure printing method, and micro gravure printing method as described above for the paint for forming a transparent film It is possible to form a transparent film by applying to a base material, drying and curing by an ordinary method such as ultraviolet irradiation, heat treatment, etc., but in the present invention, a roll coating method, a slit coater printing method, a gravure printing method, Gravure printing is recommended.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

[Example 1]
Preparation of novel silica-based hollow fine particle (1) dispersion silica-alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: USBB-120, average particle size 25 nm, SiO ₂ · Al ₂ O ₃ concentration 20% by weight, Al _{2 in} solid content 3900 g of pure water was added to 100 g of O ₃ content (27 wt%) and heated to 98 ° C., and while maintaining this temperature, 3,740 g of an aqueous sodium silicate solution having a concentration of 1.5 wt% as SiO ₂ and Al ₂ O 3,740 g of a sodium aluminate aqueous solution having a concentration of 0.5% by weight as ₃ was added over 6 hours to obtain a SiO ₂ .Al ₂ O ₃ primary particle dispersion. The pH of the reaction solution at this time was 11.8, and the solid content concentration was 0.8%. Next, 15,400 g of a 1.5 wt% sodium silicate aqueous solution as SiO ₂ and 5,100 g of a 0.5 wt% sodium aluminate aqueous solution as Al ₂ O ₃ were added over 6 hours to obtain a solid content concentration. 32,000 g of a 1.1% by weight silica-alumina-coated composite oxide particle dispersion was obtained. The average particle size was 61 nm.

  Next, 1,125 g of pure water was added to 500 g of the silica / alumina-coated composite oxide particle dispersion which had been washed by the ultrafiltration membrane method and concentrated to a solid content concentration of 13% by weight, and then concentrated hydrochloric acid (concentration 35. 5 wt%) was added dropwise to adjust the pH to 1.0, and dealumination was performed. Subsequently, the aluminum salt dissolved while adding 10 L of pH 3 aqueous hydrochloric acid and 5 L of pure water was separated and washed with an ultrafiltration membrane to obtain an aqueous dispersion of silica-based hollow fine particles having a solid content concentration of 20% by weight.

  Next, aqueous ammonia is added to the silica-based hollow fine particle dispersion to adjust the pH of the dispersion to 10.5, and after aging at 200 ° C. for 11 hours, the mixture is cooled to room temperature, and a cation exchange resin (Mitsubishi). Chemical Co., Ltd. (Diaion SK1B) 400 g was used for ion exchange for 3 hours, then anion exchange resin (Mitsubishi Chemical Co., Ltd .: Diaion SA20A) 200 g was used for ion exchange for 3 hours. Using 200 g of ion exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B), ion exchange is performed at 80 ° C. for 3 hours for washing, and an aqueous dispersion of silica-based hollow fine particles (1) having a solid content concentration of 20% by weight. Got.

  Next, 135 g of pure water was added to 100 g of the dispersion of silica-based fine particles (1) having a solid concentration of 20% by weight and stirred for 15 minutes, and then 13 g of a sodium aluminate aqueous solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain an alumina-modified silica-based hollow fine particle (1) dispersion.

  460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% were added to 230 g of the resulting alumina-modified silica-based hollow fine particle (1) dispersion having a solid content concentration of 8.5 wt% and heated to 98 ° C. While maintaining the above, 235 g of an acidic silicic acid aqueous solution having a concentration of 3.0% by weight was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (1) having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow microparticles (1) having a solid content concentration of 20% by weight, in which the solvent was replaced with ethanol using an ultrafiltration membrane, was prepared.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (1) having a solid content of 20% by weight 81.2 wt%) 3 g of the silica particles, heat-treated at 50 ° C., and again using an ultrafiltration membrane, the solvent was replaced with ethanol. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (1), the refractive index, average particle diameter, convex part size (convex _P ) and convex part height (convex _H ) were measured, and the results are shown in the table.

Preparation of paint for forming transparent film (1) Surface treatment 60 g of an aqueous dispersion of silica-based hollow fine particles (1) diluted with ethanol to a solid concentration of 5% by weight, acrylic resin (Hitaroid 1007, Hitachi Chemical ( Co., Ltd.) 2.5 g, and 17.5 (weight ratio) mixed solvent of isopropanol and n-butanol 37.5 g mixed well, and a coating composition for forming a transparent film having a solid content concentration of 5.5 wt% (1) Was prepared.

Preparation of coating liquid for forming hard coat film Silica sol dispersion (manufactured by JGC Catalysts & Chemicals Co., Ltd .; Cataloid SI-30; average particle size 12 nm, SiO ₂ concentration 40.5% by weight, dispersion medium: isopropanol, particle refractive index 1.46) 100 g is mixed with 1.88 g of γ-methacrylooxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd .: KBM-503, SiO ₂ component 81.2%) and 3.1 g of ultrapure water is added. Then, a 12 nm silica sol dispersion surface-treated by stirring at 50 ° C. for 20 hours was obtained (solid content concentration 40.5 wt%).

Thereafter, the solvent was replaced with propylene glycol monopropyl ether (PGME) by a rotary evaporator (solid content: 40.5%).
Then, a propylene glycol monopropyl ether dispersion 51.85g of solids concentration 40.5 wt% of silica sol (1-8), di-hexa erythritol triacetate (manufactured by Kyoeisha Chemical Co., _{Ltd.: D P E-6A) 18} . 90 g, and 1.6-hexanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd .; light acrylate SR-238F) 2.10 g and a silicone leveling agent (manufactured by Enomoto Kasei Co., Ltd .; Disparon 1610) 0.01 g photopolymerized. Initiator (Ciba Japan Co., Ltd.): Irgacure 184, dissolved in PGME to a solid content of 10%) 12.60 g and PGME 14.54 g are mixed well to form a hard coat film having a solid content of 42.0% by weight. A forming coating solution was prepared.

Manufacture of substrate with transparent coating (1) First, the coating liquid for forming a hard coat film was applied to a TAC film (manufactured by Panac Corporation: FT-PB80UL-M, thickness: 80 μm, refractive index: 1.51). It was applied by the coater method (# 14), dried at 80 ° C. for 120 seconds, and then cured by irradiating with 300 mJ / cm ² of ultraviolet rays to form a hard coat film. The film thickness of the hard coat film was 5 μm.

Next, the transparent film-forming paint (1) was applied by the bar coater method (bar # 4), dried at 80 ° C. for 120 seconds, then cured by irradiation with 600 mJ / cm ² of UV light in an N 2 atmosphere, and reflected. A substrate (1) with a transparent coating for prevention was prepared. At this time, the film thickness of the antireflection transparent coating was 100 nm. Table 2 shows the total light transmittance, haze, reflectance of light having a wavelength of 550 nm, coating refractive index, adhesion, pencil hardness, and scratch resistance of the substrate (1) with a transparent coating for antireflection. The total light transmittance and haze were measured with a haze meter (manufactured by Suga Test Instruments Co., Ltd.), and the reflectance was measured with a spectrophotometer (JASCO Corporation, Ubest-55). Moreover, the refractive index of the film was measured with an ellipsometer (manufactured by ULVAC, EMS-1). The uncoated PET film had a total light transmittance of 90.7%, a haze of 2.0%, and a reflectance of light having a wavelength of 550 nm of 6.0%.

Pencil hardness Pencil hardness was measured with a pencil hardness tester in accordance with JIS K 5400. That is, a pencil was set at an angle of 45 degrees with respect to the transparent coating surface, and a predetermined load was applied and pulled at a constant speed, and the presence or absence of scratches was observed.

Adhesive transparent film-coated substrate (A-1) on the surface of the substrate (A-1) with 11 parallel scratches at intervals of 1 mm in length and width to make 100 squares, cellophane tape is adhered to this, then cellophane tape is attached Adhesion was evaluated by classifying the number of cells remaining without peeling off when the film was peeled into the following three stages. The results are shown in the table.
Number of remaining squares more than 90: ◎
Number of remaining squares: 85-89: ○
Number of remaining squares: 84 or less: △

Measurement of scratch resistance Using # 0000 steel wool, sliding 50 times at a load of 500 g / cm ² , visually observing the surface of the film, and evaluating according to the following criteria, the results are shown in the table.
Evaluation criteria:
No streak injury is found: ◎
Slight flaws are observed: ○
Many streak wounds are found: △
The surface has been cut entirely: ×

Alkali resistance Evaluation of saponification resistance Saponification test method: Substrate with transparent coating (1) is immersed in a 10 wt% NaOH aqueous solution at 40C for 80 seconds. The Δ contact angle on the surface of the transparent coating before and after the saponification test was measured and evaluated according to the following criteria, and the results are shown in the table.
<Evaluation criteria>
Within ± 5 °: ◎
± 5 to 10 °: ○
± 10-20 °: △
± 20 ° or more: ×

[Example 2]
Preparation of New Silica-Based Hollow Fine Particles (2) Dispersion After adding 135 g of pure water to 100 g of silica-based fine particles (1) dispersion having a solid content of 20% by weight prepared in the same manner as in Example 1, the mixture was stirred for 15 minutes. 6.7 g of a sodium aluminate aqueous solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain alumina-modified silica-based hollow fine particles (2).

  Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% were added to 230 g of the alumina-modified silica-based hollow fine particle (2) dispersion having a solid content concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 182 g of a 3.0 wt% aqueous silicic acid solution was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (2) having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow microparticles (2) having a solid content concentration of 20% by weight was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (2) having a solid content of 20% by weight 81.2 wt%) 3 g of the silica particles, heat-treated at 50 ° C., and again using a ultrafiltration membrane, the solvent was replaced with ethanol. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (2), the refractive index, average particle diameter, convex part size (convex _P ) and convex part height (convex _H ) were measured, and the results are shown in the table.

Preparation of transparent film-forming coating material (2) In Example 1, for the formation of a transparent film having a solid content of 5.5% by weight, except that an alcohol dispersion of the surface treated novel silica-based hollow fine particles (2) was used. A paint (2) was prepared.

Production of substrate with transparent film (2) A substrate with transparent film (2) was obtained in the same manner as in Production Example 1 except that the paint for forming a transparent film (2) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance of this substrate with transparent film (2) were measured, and the results are shown in the table.

[Example 3]
Preparation of novel silica-based hollow fine particle (3) dispersion liquid After adding 135 g of pure water to 100 g of silica-based fine particle (1) dispersion liquid having a solid concentration of 20% by weight prepared in the same manner as in Example 1, the mixture was stirred for 15 minutes. 13 g of an aqueous sodium aluminate solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain alumina-modified silica-based hollow fine particles (3).

  Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% are added to 230 g of the alumina-modified silica-based hollow fine particle (3) dispersion having a solid content concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 274 g of a 3.0% by weight aqueous silicic acid solution was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (3) having convex portions on the surface.

Next, an alcohol dispersion of a novel silica-based hollow microparticle (3) having a solid content concentration of 20% by weight was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (3) having a solid content of 20% by weight 81.2% by weight) 3 g was added, heat-treated at 50 ° C., and the solvent was replaced with ethanol again using an ultrafiltration membrane. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (3), the refractive index, the average particle diameter, the size of the convex portions (convex _P ) and the height of the convex portions (convex _H ) are measured, and the results are shown in the table.

Preparation of transparent film-forming coating material (3) In Example 1, for the formation of a transparent film having a solid content of 5.5% by weight, except that an alcohol dispersion of the surface-treated novel silica-based hollow fine particles (3) was used. A paint (3) was prepared.

Production of transparent film-coated substrate (3) In Example 1, a transparent film-coated substrate (3) was obtained in the same manner except that the transparent film-forming paint (3) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance evaluation of this substrate with transparent film (3) were measured, and the results are shown in the table.

[Example 4]
Preparation of novel silica-based hollow fine particle (4) dispersion liquid After adding 135 g of pure water to 100 g of silica-based fine particle (1) dispersion liquid having a solid content of 20% by weight prepared in the same manner as in Example 1, the mixture was stirred for 15 minutes. 20 g of an aqueous sodium aluminate solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain alumina-modified silica-based hollow fine particles (4).

  Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% are added to 230 g of the alumina-modified silica-based hollow fine particle (4) dispersion having a solid concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 306 g of a 3.0% by weight aqueous silicic acid solution was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (4) having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow microparticles (4) having a solid content concentration of 20% by weight, in which the solvent was replaced with ethanol using an ultrafiltration membrane, was prepared.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacrylsilane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (4) having a solid content of 20% by weight 81.2% by weight) 3 g of the mixture, heat-treated at 50 ° C., and again using a ultrafiltration membrane, the solvent was replaced with ethanol. ) Alcohol dispersion was prepared.
For the obtained novel silica-based hollow fine particles (4), the refractive index, average particle diameter, convex size (convex _P ) and convex height (convex _H ) were measured, and the results are shown in the table.

Preparation of paint for forming transparent film (4) In Example 1, for the preparation of transparent film having a solid content concentration of 5.5% by weight, except that an alcohol dispersion of the surface-treated novel hollow silica fine particles (4) was used. A paint (4) was prepared.

Production of transparent film-coated substrate (4) A transparent film-coated substrate (4) was obtained in the same manner as in Production Example 1 except that the transparent film-forming paint (4) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance of this substrate with transparent film (4) were measured, and the results are shown in the table.

[Example 5]
Preparation of paint for forming transparent film (5) In Example 1, 41 g of a dispersion of a surface-treated novel silica-based hollow fine particle (1) diluted with ethanol to a solid content concentration of 5% by weight, and acrylic resin (Hitachi) Transparent with a solids concentration of 5.5% by weight, except that 3.7 g of Hitachi Chemical 1007) and 60 g of a 1/1 (weight ratio) mixed solvent of isopropanol and n-butanol were sufficiently mixed. A film-forming paint (5) was prepared.

Production of transparent film-coated substrate (5) In Example 1, a transparent film-coated substrate (5) was obtained in the same manner except that the transparent film-forming paint (5) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance evaluation of this substrate with transparent film (5) were measured, and the results are shown in the table.

[Example 6]
Preparation of paint for forming transparent film (6) Surface treatment 65.5 g of a dispersion of a novel silica-based hollow fine particle (1) diluted with ethanol to a solid content concentration of 5% by weight and acrylic resin (Hitachi Chemical Co., Ltd.) ) Made: Hitaloid 1007,) 3.3 g and transparent with a solid content concentration of 5.5% by weight, except that 50.8 g of a mixed solvent of isopropanol and n-butanol 1/1 (weight ratio) was thoroughly mixed. A film-forming paint (6) was prepared.

Production of transparent film-coated substrate (6) A transparent film-coated substrate (6) was obtained in the same manner as in Production Example 1 except that the transparent film-forming paint (6) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance evaluation of this transparent film-coated substrate (6) were measured, and the results are shown in the table.

[Example 7]
Preparation of novel silica-based hollow fine particle (7) dispersion silica-alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: USBB-120, average particle size 25 nm, SiO ₂ · Al ₂ O ₃ concentration 20% by weight, Al _{2 in} solid content 3900 g of pure water was added to 100 g of O ₃ content (27 wt%) and heated to 98 ° C. While maintaining this temperature, 740 g of an aqueous sodium silicate solution having a concentration of 1.5 wt% as SiO ₂ and Al ₂ O ₃ were used. Then, 740 g of a sodium aluminate aqueous solution having a concentration of 0.5% by weight was added over 6 hours to obtain a SiO ₂ .Al ₂ O ₃ primary particle dispersion. The pH of the reaction solution at this time was 11.8, and the solid content concentration was 0.6%. Next, 7,500 g of 1.5 wt% sodium silicate aqueous solution as SiO ₂ and 2,500 g of 0.5 wt% sodium aluminate aqueous solution as Al ₂ O ₃ were added over 6 hours to obtain a solid content concentration. 15,000 g of a 1.0 wt% silica / alumina-coated composite oxide particle dispersion was obtained. Moreover, the average particle diameter was 40 nm.

  Next, 1,125 g of pure water was added to 500 g of the silica / alumina-coated composite oxide particle dispersion which had been washed by the ultrafiltration membrane method and concentrated to a solid content concentration of 13% by weight, and then concentrated hydrochloric acid (concentration 35. 5 wt%) was added dropwise to adjust the pH to 1.0, and dealumination was performed. Subsequently, the aluminum salt dissolved while adding 10 L of pH 3 aqueous hydrochloric acid and 5 L of pure water was separated and washed with an ultrafiltration membrane to obtain an aqueous dispersion of silica-based hollow fine particles having a solid content concentration of 20% by weight.

  Next, aqueous ammonia is added to the silica-based hollow fine particle dispersion to adjust the pH of the dispersion to 10.5, and after aging at 200 ° C. for 11 hours, the mixture is cooled to room temperature, and a cation exchange resin (Mitsubishi). Chemical Co., Ltd. (Diaion SK1B) 400 g was used for ion exchange for 3 hours, then anion exchange resin (Mitsubishi Chemical Co., Ltd .: Diaion SA20A) 200 g was used for ion exchange for 3 hours. Using 200 g of ion exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B), ion exchange is performed at 80 ° C. for 3 hours for washing, and an aqueous dispersion of silica-based hollow fine particles (1) having a solid content concentration of 20% by weight. Got.

  Next, 135 g of pure water was added to 100 g of a silica-based fine particle (2) dispersion having a solid content of 20% by weight and stirred for 15 minutes. Then, 20 g of a sodium aluminate aqueous solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain an alumina-modified silica-based hollow fine particle (7) dispersion.

  Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% were added to 230 g of the alumina-modified silica-based hollow fine particle (7) dispersion having a solid concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 352 g of a 3.0% by weight aqueous silicic acid solution was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (7) having convex portions on the surface.

Next, an alcohol dispersion of a novel silica-based hollow fine particle (7) having a solid content concentration of 20% by weight was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (7) having a solid content concentration of 20% by weight 81.2% by weight) 3 g of the mixture, heat-treated at 50 ° C., and again using ultrafiltration membranes, the solvent was replaced with ethanol. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (7), the refractive index, the average particle diameter, the size of the convex portions (convex _P ) and the height of the convex portions (convex _H ) are measured, and the results are shown in the table.

Preparation of Transparent Film Forming Paint (7) In Example 1, the solid content concentration was 5.5 in the same manner except that an alcohol dispersion of the surface-treated novel silica-based hollow fine particles (7) having a solid content concentration of 20% by weight was used. A paint (2) for forming a transparent coating film with a weight% was prepared.

Production of transparent film-coated substrate (7) In Example 1, a transparent film-coated substrate (7) was obtained in the same manner except that the transparent film-forming paint (7) was used. The transparent film-coated substrate (7) was evaluated for total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance, and the results are shown in the table.

[Example 8]
Preparation of New Silica-Based Hollow Fine Particle (8) Dispersion Silica-Alumina Sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: USBB-120, average particle size 25 nm, SiO ₂ · Al ₂ O ₃ concentration 20% by weight, Al _{2 in} solid content 3900 g of pure water was added to 100 g of O ₃ content (27 wt%) and heated to 98 ° C., and while maintaining this temperature, 9,600 g of an aqueous sodium silicate solution having a concentration of 1.5 wt% as SiO ₂ and Al ₂ O 9,600 g of a sodium aluminate aqueous solution having a concentration of 0.5% by weight as No. ₃ was added in 6 hours to obtain a SiO ₂ .Al ₂ O ₃ primary particle dispersion. The pH of the reaction solution at this time was 11.8, and the solid content concentration was 0.9%. Subsequently, 34,400 g of a 1.5 wt% sodium silicate aqueous solution as SiO ₂ and 11,500 g of a 0.5 wt% sodium aluminate aqueous solution as Al ₂ O ₃ were added over 6 hours to obtain a solid content concentration. As a result, 69,000 g of a 1.1 wt% silica / alumina-coated composite oxide particle dispersion was obtained. The average particle size was 81 nm.

  Next, 1,125 g of pure water was added to 500 g of the silica / alumina-coated composite oxide particle dispersion which had been washed by the ultrafiltration membrane method and concentrated to a solid content concentration of 13% by weight, and then concentrated hydrochloric acid (concentration 35. 5 wt%) was added dropwise to adjust the pH to 1.0, and dealumination was performed. Next, the aluminum salt dissolved while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water was separated and washed with an ultrafiltration membrane to obtain an aqueous dispersion (8) of silica-based hollow fine particles having a solid content concentration of 20% by weight. .

  Next, 135 g of pure water was added to 100 g of a dispersion of silica-based fine particles (8) having a solid concentration of 20% by weight and stirred for 15 minutes, and then 18 g of a sodium aluminate aqueous solution having a concentration of 0.9% by weight was added over 4 hours. Thereafter, the mixture was heated to 90 ° C. and aged for 3 hours to obtain a dispersion of alumina-modified silica-based hollow fine particles (8).

  Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% are added to 230 g of the alumina-modified silica-based hollow fine particle (8) dispersion having a solid concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 312 g of a 3.0% by weight aqueous silicic acid solution was added over 14 hours to obtain a dispersion of novel silica-based hollow fine particles (8) having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow microparticles (8) having a solid concentration of 20% by weight, in which the solvent was replaced with ethanol using an ultrafiltration membrane, was prepared.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of novel silica-based hollow fine particles (8) having a solid content of 20% by weight 81.2% by weight) 3 g was added, heat-treated at 50 ° C., and the solvent was replaced with ethanol again using an ultrafiltration membrane. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (8), the refractive index, the average particle diameter, the size of the convex portions (convex _P ) and the height of the convex portions (convex _H ) are measured, and the results are shown in the table.

Preparation of Transparent Film Forming Paint (8) In Example 1, the solid content concentration was 5.5 except that an alcohol dispersion of the surface-treated novel silica-based hollow fine particles (8) having a solid content concentration of 20% by weight was used. A paint (8) for forming a transparent coating film with a weight% was prepared.

Production of transparent film-coated substrate (8) A transparent film-coated substrate (8) was obtained in the same manner as in Production Example 1 except that the transparent film-forming paint (8) was used. The transparent film-coated substrate (8) was measured for total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance evaluation, and the results are shown in the table.

[Comparative Example 1]
Preparation of Silica Hollow Fine Particle (R1) Dispersion Ion exchange was carried out in the same manner as in Example 1 to obtain a water dispersion of silica hollow fine particles (1) having a solid content concentration of 20% by weight.

Next, an alcohol dispersion of silica-based hollow fine particles (R1) having a solid content concentration of 20% by weight was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component 81) as a methacryl silane coupling agent was added to 100 g of an alcohol dispersion of silica-based hollow fine particles (1) having a solid content of 20% by weight. .2 wt%) 3 g was added, heat-treated at 50 ° C., and the surface-treated silica-based hollow fine particles (R1) having a solid content concentration of 20 wt% were substituted with ethanol using an ultrafiltration membrane again. An alcohol dispersion was prepared.

Preparation of Transparent Film Forming Paint (R1) In Example 1, the solid content concentration was 5.5 wt.% Except that an alcohol dispersion of surface-treated silica-based hollow fine particles (R1) having a solid content concentration of 20 wt% was used. % Transparent film-forming paint (R1) was prepared.

Production of substrate with transparent coating (R1) A substrate with transparent coating (R1) was obtained in the same manner as in Example 1 except that the coating for forming a transparent coating (R1) was used. The total light transmittance, haze, reflectance, coating refractive index, adhesion, pencil hardness, scratch resistance and saponification resistance evaluation of this transparent film-coated substrate (R1) were measured, and the results are shown in the table.

[Comparative Example 2]
Preparation of New Silica-Based Hollow Fine Particle (R2) Dispersion Alumina-modified silica-based hollow fine particles (2) were obtained in the same manner as in Example 1.
Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% were added to 230 g of the alumina-modified silica-based hollow fine particle (2) dispersion having a solid content concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 52 g of a 3.0% by weight aqueous silicic acid solution was added over 14 hours to obtain a novel silica-based hollow fine particle (R2) dispersion having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow fine particles (R2) having a solid content of 20% by weight, in which the solvent was replaced with ethanol using an ultrafiltration membrane, was prepared.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (R2) having a solid content concentration of 20% by weight 81.2% by weight) 3 g was added, heat-treated at 50 ° C., and the solvent was replaced with ethanol again using an ultrafiltration membrane. ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (R2), the refractive index, average particle diameter, convex size (convex _P ) and convex height (convex _H ) were measured, and the results are shown in the table.

Preparation of transparent film-forming coating material (R2) In Example 1, for the formation of a transparent film having a solid content concentration of 5.5% by weight, except that an alcohol dispersion of the surface treated novel silica-based hollow fine particles (R2) was used. A paint (R2) was prepared.

Production of substrate with transparent coating (R2) A substrate with transparent coating (R2) was obtained in the same manner as in Example 1 except that the coating for forming a transparent coating (R2) was used. The total light transmittance, haze, reflectance, film refractive index, adhesion, pencil hardness, scratch resistance and saponification resistance evaluation of this substrate with transparent film (R2) were measured, and the results are shown in the table.

[Comparative Example 3]
Preparation of New Silica-Based Hollow Fine Particle (R3) Dispersion Alumina-modified silica-based hollow fine particles (2) were obtained in the same manner as in Example 1.
Next, 460 g of pure water and 6 g of a sodium silicate aqueous solution with a concentration of 29% were added to 230 g of the alumina-modified silica-based hollow fine particle (2) dispersion having a solid content concentration of 8.5% by weight and heated to 98 ° C. While maintaining the above, 587 g of a 3.0 wt% aqueous silicic acid solution was added over 14 hours to obtain a novel silica-based hollow fine particle (R3) dispersion having convex portions on the surface.

Next, an alcohol dispersion of novel silica-based hollow fine particles (R3) having a solid content concentration of 20% by weight, in which the solvent was replaced with ethanol using an ultrafiltration membrane, was prepared.
Γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-503, SiO ₂ component) as a methacryl silane coupling agent to 100 g of an alcohol dispersion of a novel silica-based hollow fine particle (R3) having a solid content of 20% by weight 81.2% by weight) 3 g was added, heat-treated at 50 ° C., and the solvent was replaced with ethanol again using an ultrafiltration membrane, and the surface-treated novel silica-based hollow fine particles (R3 ) Alcohol dispersion was prepared.
With respect to the obtained novel silica-based hollow fine particles (R3), the refractive index, average particle diameter, convex size (convex _P ) and convex height (convex _H ) were measured, and the results are shown in the table.

Preparation of transparent film-forming paint (R3) In Example 1, except that an alcohol dispersion of surface-treated novel silica-based hollow fine particles (R3) was used, a transparent film-forming film having a solid content concentration of 5.5% by weight was used. A paint (R3) was prepared.

Production of substrate with transparent coating (R3) A substrate with transparent coating (R3) was obtained in the same manner as in Example 1 except that the coating for forming a transparent coating (R3) was used. The total light transmittance, haze, reflectance, coating refractive index, adhesion, pencil hardness, scratch resistance, and saponification resistance of this substrate with transparent coating (R3) were measured, and the results are shown in the table.

[Comparative Example 4]
Preparation of Transparent Film Forming Coating Material (R4) In Example 1, 11 g of an alcohol dispersion of surface-treated novel silica-based hollow fine particles (1) diluted with ethanol to a solid content concentration of 5% by weight, and acrylic resin (Hitachi) Kasei Co., Ltd .: Forming a transparent film having a solid content of 5.5% by weight, except that 1007, 5 g of hyaloid and 85 g of a 1/1 (weight ratio) mixed solvent of isopropanol and n-butanol were sufficiently mixed. A paint (R4) was prepared.

Production of substrate with transparent coating (R4) A substrate with transparent coating (R4) was obtained in the same manner as in Production Example 1 except that the coating for forming a transparent coating (R4) was used. The total light transmittance, haze, reflectance, coating refractive index, adhesion, pencil hardness, scratch resistance and saponification resistance evaluation of this substrate with transparent coating (R4) were measured, and the results are shown in the table.

[Comparative Example 5]
Preparation of paint for transparent film formation (R5) Surface treatment New silica-based hollow fine particle (1) alcohol dispersion of 98g diluted with ethanol to a solid content concentration of 5% by weight, acrylic resin (manufactured by Hitachi Chemical Co., Ltd.) : Hitaloid 1007) For forming a transparent film having a solid content concentration of 5.5% by weight, except that 0.6 g and 1.4 g of a mixed solvent of isopropanol and n-butanol 1/1 (weight ratio) were sufficiently mixed. A paint (R5) was prepared.

Production of substrate with transparent coating (R5) A substrate with transparent coating (R5) was obtained in the same manner as in Example 1 except that the coating for forming a transparent coating (R5) was used. The total light transmittance, haze, reflectance, coating refractive index, adhesion, pencil hardness, scratch resistance and saponification resistance evaluation of this substrate with transparent film (R5) were measured, and the results are shown in the table.

Claims (7)

The average particle size (D _P ) is in the range of 25 to 200 nm, the surface has a convex portion, and the average diameter (convex _P ) of the bottom surface portion of the convex portion is 1/40 to the average particle size (D _P ). The height of the convex part (convex _H ) is in the range of 1/10 to 1/1 of the average diameter (convex _P ) of the bottom surface part of the convex part (the average particle diameter is For any 20 particles, the longest diameter (D _L ) and the diameter (D _S ) perpendicular to the longest diameter are measured, the particle diameter is ½ of (D _L ) + (D _S ), Silica-based hollow fine particles characterized by the above.  2. The silica-based hollow fine particles according to claim 1, wherein the refractive index is in the range of 1.10 to 1.35. The silica-based hollow fine particles are
(i) preparing an aqueous dispersion of silica-based hollow fine particles having an average particle diameter of 20 to 200 nm and a silica coating layer having a thickness of 1 to 20 nm;
(ii) Alkali aluminate aqueous solution is added thereto as Al ₂ O _{3 so} as to be 0.01 to 10% by weight of the solid content weight of the silica-based hollow fine particles. Forming a base,
(iii) Next, after adding an alkali silicate aqueous solution in the range of 0.1 to 30% by weight of the solid content weight of the silica-based hollow fine particles as SiO ₂ ,
(iv) Heating to 40 to 150 ° C., adding the acidic silicic acid solution as SiO _{2 in} the range of 1 to 100 % by weight of the solid content weight of the silica-based hollow fine particles, so that the silica in the acidic silicic acid solution The silica-based hollow fine particles according to claim 1, wherein the silica-based hollow fine particles are precipitated on the alumina base to form convex portions. The silica-based hollow fine particles according to any one of claims 1 to 3, a matrix- forming component and a polar solvent,
The concentration of the silica-based hollow fine particles is in the range of 0.2 to 40% by weight as the solid content, the concentration of the matrix forming component is in the range of 0.2 to 40% by weight as the solid content, and the total solid content concentration is 1.0 to 50% by weight. A coating for forming a transparent film, characterized in that it is contained in the range of%.   The coating material for forming a transparent film according to claim 4, wherein the matrix forming component is an ultraviolet curable resin.   A base material with a transparent film, which is formed on the base material using the transparent film-forming paint according to claim 4 and has a transparent film having a content of silica-based hollow fine particles of 20 to 80% by weight.   The substrate with a transparent coating according to claim 6, wherein the transparent coating has a thickness of 30 to 300 nm and a refractive index in the range of 1.20 to 1.50.