KR101633530B1 - Chain-shaped Silica-based Hollow Fine Particles and Process for Producing Same, Coating Fluid for Transparent Coating Film Formation Containing the Fine Particles, and Substrate with Transparent Coating Film - Google Patents

Abstract

Provided is a chain-silica-based hollow fine particle having a low refractive index and having a cavity penetrating the inside of the outer shell. The chain-like silica hollow fine particles have an outward angle and have silica-based hollow fine particles (primary particles) having an internal cavity connected in a chain-like manner, through holes through which the hollows pass each other, and have an average length (L) of 20 To 1500 nm, an average width (W) in the range of 10 to 300 nm, and a refractive index in the range of 1.10 to 1.35. The outer thickness T _S is in the range of 2 to 100 nm and the ratio of the average width W to the average width T _S / W is in the range of 0.05 to 0.30.

Description

[0001] The present invention relates to a chain-silica-based hollow microparticle, a process for producing the same, a coating liquid for forming a transparent coating film containing the microparticle, and a transparent film- Fine Particles, and Substrate with Transparent Coating Film}

The present invention relates to a process for producing a porous silica-based hollow microparticle, which comprises a chain-like silica-based hollow microparticle having a cavity penetrated therein, a process for producing the chain silica-based hollow microparticle, a coating liquid for forming a transparent coating film containing the chain- And a transparent coating film containing fine particles formed on the surface of the substrate.

Conventionally, hollow silica particles having a particle diameter of about 0.1 to 300 mu m are known (see Patent Document 1, Patent Document 2, etc.). A method for producing hollow particles comprising a dense silica shell by precipitating active silica from an alkali metal silicate aqueous solution on a core made of a material other than silica and removing the material without destroying the silica shell is known (See Patent Document 3, etc.).

In addition, a spherical silica particle of micron size is known, which is a core-shell structure having a shell, a hollow portion at its outer periphery, a dense outer shell, and a concentration gradient structure at its inner periphery.

The applicant of the present application first proposes that composite oxide fine particles having a nanometer size with a low refractive index can be obtained by completely covering the surface of porous inorganic oxide fine particles with silica or the like (refer to Patent Document 5) Further, by forming a silica coating layer on the core particle of the composite oxide comprising silica and an inorganic oxide other than silica, then removing the inorganic oxide other than the silica, and coating the silica with the silica if necessary, Of silica-based fine particles of nanometer size can be obtained (see Patent Document 6).

On the other hand, the applicant of the present applicant has proposed, first, to form silica particles in a chain form by subjecting the silica particles to a hydrothermal treatment under a slightly acidic condition (see Patent Document 7). In the non-hollow particle, since the particle refractive index is not less than 1.45, in order to obtain particles having a lower refractive index, Applicant further added an electrolyte material in the hollow silica particle forming step to form a chain-like hollow silica particle (See Patent Documents 8 and 9).

However, in the silica-based hollow particles according to the proposal of the applicant of the present application, a sufficient low refractive index effect may not be obtained depending on the purpose and use of the particles. That is, even when the inside of individual particles is hollowed, there is a limit in the joint volume in terms of particle strength, and there is a limit to the lowering of the refractive index. Therefore, silica-based hollow fine particles having a particle structure different from the conventional one are required.

Japanese Unexamined Patent Publication No. 6-330606 Japanese Unexamined Patent Publication No. 7-013137 Japanese Patent Application Laid-Open No. 2000-500113 Japanese Unexamined Patent Publication No. 11-029318 JP-A-07-133105 Japanese Patent Application Laid-Open No. 2001-233611 Japanese Patent Application Laid-Open No. 2004-055298 Japanese Patent Application Laid-Open No. 2004-099074 Patent Document 9: JP-A-2005-186435

The present invention is based on the invention described in the above patent document 6, and aims to obtain silica-based fine particles having a low refractive index. The present invention relates to a porous composite oxide particle comprising silica and an inorganic oxide other than silica Silica fine particles having a cavity penetrating into the outer shell by coating the surface of the chain-like particles with silica, and then removing the inorganic oxide other than silica, And the like.

Another object of the present invention is to provide a film-forming coating material containing the above-mentioned chain-like silica-based hollow microparticles and a film-forming matrix-forming component and having excellent stability and film-forming properties. Further, the present invention relates to a process for producing the above-mentioned chain silica fine particles, which comprises forming a film containing the above-mentioned chain silica fine particles on a surface of a substrate to form a film having a low refractive index and being excellent in adhesiveness to a substrate, strength, abrasion resistance, It is an object of the present invention to provide a coated substrate.

The chain-silica hollow microparticles according to the present invention are characterized in that silica-based hollow microparticles (primary particles) having an outer shell at the outside and connected to each other in a chain form have through holes through which the hollows communicate with each other, ) Is in the range of 20 to 1500 nm, the average width (W) is in the range of 10 to 300 nm, and the refractive index is in the range of 1.10 to 1.35.

It is preferable that the thickness T _S of the outer angle is in the range of 2 to 100 nm and the ratio (T _S / W) of the outer width to the average width W is in the range of 0.05 to 0.30.

It is preferable that the ratio (D _S / W) of the average diameter (D _S ) of the through holes to the average width (W) is in the range of 0.1 to 0.9.

It is preferable that the molar ratio MO _x / SiO ₂ of the inorganic oxide other than silica and silica and represented by MO _x in the inorganic oxide other than silica is in the range of 0.0001 to 0.2.

The method for producing the chain-silica-based hollow microparticles according to the present invention is characterized by comprising the following steps (a) to (f).

(a) an aqueous solution of an aqueous solution of a silicate and / or an acidic silicic acid solution and an aqueous solution of an inorganic alkali soluble in an alkali aqueous solution, or a seed particle having a solid concentration in a range of 0.01 to 2 wt% of the composite oxide is in a range of the addition at the same time in the dispersed aqueous alkali solution, molar ratio of MO _X / SiO ₂ (a) when the display silica as SiO _2, and displays the inorganic oxide other than silica as MO _X is from 0.1 to 2 Process for preparing primary particle dispersion

(b) a step of washing the primary particle dispersion liquid

(c) a step of subjecting the washed primary particle dispersion liquid to hydrothermal treatment at 50 to 300 占 폚 in the presence of an electrolyte to prepare a dispersion of the chain-like composite oxide particles

(d) a step of forming a silica or silica-alumina coating layer and preparing a dispersion of silica or silica-alumina coated complex oxide particles

(e) adding an acid to the dispersion of silica or silica-alumina coated complex oxide particles to remove at least a part of elements other than silicon constituting the composite oxide particles to obtain a chain silica fine hollow fine particle dispersion

(f) a step of washing the obtained dispersion liquid

It is preferable that the electrolyte in the step (c) is an alkaline earth metal salt.

Following the step (f), it is preferable to carry out the following step (g).

(g) a step of hydrothermally treating the dispersion of chain silica-based hollow fine particles in the range of 50 to 300 캜

It is preferable that the step (d) is any one of the following steps (d-1), (d-2) and (d-3).

(d-1) adding an alkali aqueous solution and an organic silicon compound represented by the following formula (1) and / or a partial hydrolyzate thereof to the dispersion of the stratiform composite oxide particles obtained in the step (c) Step of forming a silica coating layer

R _n SiX _(4-n) (One)

R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an acryl group, an epoxy group, a methacryl group, an amino group or a CF ₃ group, X is an alkoxy group having 1 to 4 carbon atoms, a silanol group, , and n is an integer of 0 to 3]

(d-2) a step of adding an alkali aqueous solution and an acidic silicic acid solution to the dispersion of the steric complex oxide particles obtained in the step (c) and forming a silica coating layer on the steric complex oxide particle

(d-3) a step of adding an alkali silicate aqueous solution and an aqueous aluminic acid solution to the dispersion of the stratified composite oxide particles obtained in the step (c) to form a silica-alumina clad layer on the stratified composite oxide particle

The coating liquid for forming a transparent coating film according to the present invention is characterized by comprising the above chain-like silica-based hollow fine particles and a matrix-forming component.

The transparent film-coated base material according to the present invention is characterized in that the transparent film formed by using the coating liquid for forming a transparent film is formed on the base material surface alone or together with other films.

According to the present invention, it is possible to provide new chainlike silica-based hollow fine particles having cavities penetrating into the inside of the shell. The novel chainlike silica-based hollow fine particles have a lower refractive index than the silica-based hollow fine particles to which the hollow fine particles are connected in a chain.

According to the production method of the present invention, chain-silica-based hollow fine particles having a low refractive index can be provided.

Further, it is possible to provide a film-forming coating material containing the above-mentioned chain-like silica-based hollow fine particles and a film-forming matrix-forming component and having excellent stability and film-forming property.

In addition, it is possible to provide a film-attached substrate having a coating film containing the chain-like silica-based hollow fine particles on the surface of the substrate and having a low refractive index and excellent adhesion to the substrate, strength, scratch resistance and reflection-

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a cross-section of chain-silica hollow fine particles of the present invention. FIG.

[Chained silica-based hollow fine particles]

First, the chain-silica hollow microparticles according to the present invention will be described.

The chain-silica hollow microparticles according to the present invention are characterized in that silica-based hollow microparticles (primary particles) having an outer shell on the outside and connected to each other in a chain form and having through holes through which the cavities penetrate each other, ) Is in the range of 20 to 1500 nm, the average width (W) is in the range of 10 to 300 nm, and the refractive index is in the range of 1.10 to 1.35.

Silica-based hollow fine particles (primary particles)

The chain silica-based hollow fine particles are chain-like silica hollow fine particles (primary particles) having an external angle to the outside and having a cavity therein.

Fig. 1 shows a schematic diagram of a cross section of the chain-silica-based hollow microparticles according to the present invention.

In the present invention, the size of the silica-based hollow fine particles (primary particles) is preferably in the range of 10 to 300 nm, more preferably 15 to 200 nm.

When the size of the primary particles is less than 10 nm, it tends to agglomerate with difficulty in producing a chain, and it may be difficult to obtain a chain-silica hollow fine particle having a desired low refractive index.

If the size of the primary particles exceeds 300 nm, the particles are too large and it is difficult to produce a chain, and it is also difficult to obtain the desired chain-silica hollow microparticles.

As shown in Fig. 1, the average width W of the chain-like silica-based hollow microparticles is preferably in the range of 10 to 300 nm, more preferably 15 to 200 nm, as much as the primary particle size or larger.

The chain-silica-based hollow microparticles are preferably connected in chain form to the primary particles, but preferably have an average length (L) in the range of 20 to 1500 nm, more preferably 40 to 1000 nm.

When the average length (L) is less than 20 nm, it means that the number of primary particles having a minimum particle diameter of 10 nm is less than 2. This means that the average length (L) is not 1500 nm There is a case where it is difficult to obtain the desired chain-like silica-based hollow fine particles by aggregation or intertwining with each other.

The thickness T _S of the outer angle is preferably in the range of 2 to 100 nm, more preferably 3 to 50 nm, although it varies depending on the primary particle diameter or the average width W.

If the thickness T _S of the shell is less than 2 nm, the hollow structure may not be maintained when at least a part of the elements other than silicon is removed, and it may be difficult to obtain the desired chain-silica hollow fine particles.

When the thickness T _S of the outer shell exceeds 100 nm, the voids inside are small, and it may be difficult to obtain the chain-silica hollow fine particles having a desired low refractive index.

It is also preferable that the thickness (T _S ) of the outer shell has a ratio (T _S / W) to the average width w of 0.05 to 0.30, more preferably 0.05 to 0.2.

(T _S ) / (W) is less than 0.05, the hollow structure can not be maintained when at least a part of elements other than silicon is removed, and it may be difficult to obtain chain-silica hollow microparticles.

(T _S ) / (W) exceeds 0.30, the voids inside are small and it may be difficult to obtain the chain-silica hollow fine particles having a desired low refractive index.

It is preferable that the ratio (D _S / W) of the average diameter (D _S ) of the through holes to the average width (W) is in the range of 0.1 to 0.9, more preferably 0.3 to 0.8.

When (D _S ) / (W) is less than 0.1, it is difficult to obtain the chain-silica hollow fine particles having a desired low refractive index because the voids in the through holes are small and the contribution to the lowering of the refractive index is small.

It is difficult to obtain chain-silica-based hollow fine particles having a ratio (D _S ) / (W) of more than 0.9.

The chain silica fine hollow fine particles preferably have a refractive index in the range of 1.10 to 1.35, and more preferably in the range of 1.10 to 1.30.

When the refractive index of the chain silica fine particles is less than 1.10, it is difficult to obtain and when the refractive index exceeds 1.35, the adhesion to the base material, the strength and scratch resistance are excellent, but the antireflection capability is sometimes insufficient.

Chain hollow silica-based fine particles according to the present invention is composed of an inorganic oxide other than silica and silica, that the molar ratio of MO _X / SiO ₂ when the display the inorganic oxide other than silica as MO _X in the range of 0.0001 to 0.2 desirable.

It is difficult to obtain a chain-silica-based hollow fine particle having a molar ratio MO _x / SiO ₂ of less than 0.0001, and a molar ratio MO _x / SiO ₂ of more than 0.2 means that the removal of inorganic oxides other than silica is small The chain-silica-based hollow fine particles having a low refractive index can not be obtained.

In the chain-silica hollow fine particles of the present invention, inorganic oxides other than silica 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 , WO ₃ , And the like. As the two or more kinds of inorganic oxides, TiO ₂ -Al ₂ O ₃ , TiO ₂ -ZrO ₂ And the like. Of these, Al ₂ O ₃ is preferable.

On the other hand, the average length (L) and the average width (W) of the chain-silica hollow microparticles of the present invention were measured by transmission electron microscope (TEM) photographs of the chain silica fine hollow microparticles The length and width are measured and obtained as the average value.

The average thickness (T _S ) of the external angle and the average diameter (D _S ) of the through hole can be measured by observing a transmission electron microscope photograph (TEM) of the particle cross section.

The refractive index is obtained by the following procedure.

(1) The chain silica-based hollow fine particle dispersion is collected with an evaporator, and the dispersion medium is evaporated.

(2) This is dried at 120 占 폚 to obtain a powder.

(3) A standard refractive index liquid having a known refractive index is dropped onto a glass plate of 2 or 3 drops, and the powder is mixed with the glass.

(4) The operation of the above (3) is carried out with various standard refractive index liquids, and the refractive index of the standard refractive index liquid when the mixed liquid becomes transparent is defined as the refractive index of the chain silica fine hollow microparticles.

[Production method of silica-based fine particles]

Next, the production method of the chain-silica-based hollow fine particles of the present invention will be described. The method for producing the chain-silica-based hollow microparticles according to the present invention is characterized by comprising the following steps (a) to (f).

(a) an aqueous solution of a silicate and / or an acidic silicic acid solution and an aqueous solution of an inorganic compound capable of dissolving an alkali are simultaneously added to an aqueous alkali solution or an aqueous alkali solution in which seed particles having a solid content concentration of 0.01 to 2% a step of displaying a silica SiO _2, and the molar ratio of MO _X / SiO ₂ (a) when displaying an inorganic oxide other than silica as the MO _X prepare a dispersion of primary particles of the complex oxide is in the range of from 0.1 to 2

(b) a step of washing the primary particle dispersion liquid

(c) a step of subjecting the washed primary particle dispersion liquid to hydrothermal treatment at 50 to 300 占 폚 in the presence of an electrolyte to prepare a dispersion of the chain-like composite oxide particles

(d) a step of forming a silica or silica-alumina coating layer and preparing a dispersion of silica or silica-alumina coated complex oxide particles

(e) adding an acid to the dispersion of silica or silica-alumina coated complex oxide particles to remove at least a part of elements other than silicon constituting the composite oxide particles to obtain a chain silica fine hollow fine particle dispersion

(f) a step of washing the obtained dispersion liquid

Step (a)

As the silicate, one or two or more silicates selected from alkali metal silicates, ammonium silicates and silicates of organic bases are preferably used. Examples of the alkali metal silicate include sodium silicate (water glass) and potassium silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salts, and amines such as monoethanolamine, diethanolamine and triethanolamine. Silicates of ammonium Or an organic base includes an alkaline solution in which ammonia, a quaternary ammonium hydroxide, an amine compound or the like is added to the silicate solution.

As the acidic silicic acid solution, it is possible to use a silicate solution obtained by removing the alkali by treating an alkali silicate aqueous solution with a cation exchange resin, and in particular, a silicic acid solution having a pH of _{2 to} pH 4 and an SiO ₂ concentration of about 7% Silicic acid solution is preferred.

As the inorganic oxide, at least, such as _{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, WO 3 Or two or more. TiO ₂ -Al ₂ O ₃ , TiO ₂ -ZrO ₂ and the like can be exemplified as two or more kinds of inorganic oxides.

Among them, Al ₂ O ₃ is preferable because spherical primary particles are easily obtained and easily removed.

As the raw material of such an inorganic oxide, it is preferable to use an alkali-soluble inorganic compound. Examples of the inorganic oxide include alkali metal salts or alkaline earth metal salts, ammonium salts and quaternary ammonium salts of oxides of metals or non- More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium tartrate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, sodium phosphate and the like are suitable.

In order to prepare the primary particle dispersion of the composite oxide, an aqueous alkali solution of the inorganic compound is prepared separately, or a mixed aqueous solution is prepared in advance, and the aqueous solution is mixed with the inorganic oxide other than the objective silica In an alkali aqueous solution, preferably in an alkaline aqueous solution having a pH of at least 10, with stirring.

The addition ratio of the silica raw material and an inorganic compound raw material is added in the alkaline aqueous solution, show a silica component as SiO _2, and MO in a molar ratio _X / SiO ₂ when the display of an inorganic compound other than silica in MO _X 0.01~2, especially , And preferably in the range of 0.1 to 1. On the other hand, when MO _x / SiO ₂ is more than 2, it is difficult to obtain spherical composite oxide primary particles when MO _x / SiO ₂ is less than 0.01 The spherical composite oxide fine particles are broken when the elements other than silicon are removed even if they are difficult to obtain, and as a result, chain-silica hollow fine particles having cavities therein can not be obtained in some cases.

When the molar ratio MO _x / SiO ₂ is in the range of 0.01 to 2, the structure of the composite oxide primary particles becomes a structure in which elements other than silicon and silicon are alternately bonded via oxygen. That is, when oxygen atoms are bonded to four bonding lines of silicon atoms, and oxygen atoms are bonded to elements other than silica, a large amount of structures are generated, and when elements other than silicon are removed in the step (e) The element M can be removed without destroying the shape of the oxide primary particles.

The average particle diameter of the composite oxide primary particles is preferably in the range of 5 to 280 nm, more preferably 10 to 200 nm.

When the average particle diameter of the composite oxide primary particles is less than 5 nm, the ratio of the outer diameter of the chain-silica hollow fine particles finally obtained becomes large so that the ratio of the void volume does not become sufficiently large, If the particle diameter exceeds 280 nm, it is difficult to form a chain in the step (b), or the removal of elements other than silicon in the step (d) becomes insufficient, so that the void volume of the chain silica fine hollow particles does not become sufficiently large, There is a case that it becomes difficult to obtain.

In the production method of the present invention, it is preferable to use a dispersion of seed particles as a starting material when preparing the primary particle dispersion of the composite oxide.

As the seed particles, inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ and CeO ₂ , or composite oxides thereof, for example, SiO ₂ -Al ₂ O ₃ , TiO ₂ -Al ₂ O ₃ , TiO ₂ -ZrO ₂ , SiO ₂ -TiO ₂ , SiO ₂ -TiO ₂ -Al ₂ O _3, and the like are usually used. The dispersion of such seed particles can be prepared by a conventionally known method. For example, it can be obtained by adding an acid or an alkali to a metal salt corresponding to the inorganic oxide, a mixture of metal salts or a metal alkoxide, hydrolyzing the mixture, and aging if necessary.

The aqueous solution of the above compound is added to the aqueous solution of the aqueous dispersion of the dispersed species of the species having been adjusted to the pH of 10 or more, while stirring, in the same manner as the method of adding the aqueous solution of the above compound into the aqueous alkali solution. As described above, when the composite oxide fine particles are grown using the seed particles as the species, it is easy to control the particle diameter of the growth particles, and it is possible to obtain a uniform particle size. The addition ratio of the silica raw material and the inorganic oxide to be added to the seed particle dispersion is in the same range as that in the case of adding to the above-described alkali aqueous solution.

The above-mentioned silica raw material and inorganic oxide raw material have a high solubility on the alkali side. However, when the two are mixed in a high pH region having a high solubility, solubility of oxo acid ions such as silicate ion and aluminate ion is lowered and these complexes precipitate and grow as colloidal particles, Growth occurs.

In the present invention, the aqueous solution of the silicate and / or the aqueous solution of the acidic silicate and the aqueous solution of the alkali-soluble inorganic compound are added until the average particle size (D _P1 ) of the composite oxide primary particles reaches 5 to 280 nm, It may be intermittent, but it is preferable to add both at the same time.

In addition, the molar ratio MO _X / SiO ₂ (A) at this time is in the range of 0.01 to 2, but may be added while changing the molar ratio to be smaller.

In the present invention, in the step (a), the composite oxide primary particles may be prepared, if necessary, in the presence of the electrolyte salt.

At this time, the ratio (M _Ea / M _Sa ) of the number of moles of electrolyte salt (M _Ea ) to the number of moles of SiO ₂ (M _sa ) can be added in the range of 0.1 to 10, preferably 0.2 to 8.

Examples of the electrolytic salts include water-soluble electrolytic salts such as sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, ammonium nitrate, ammonium sulfate, magnesium chloride and magnesium nitrate.

When electrolytic salts are used, it is preferable to add electrolytic salts at a point of time of about 1/5 to 4/5 of the average particle diameter of the composite oxide primary particles that can be obtained. The total amount may be added at this point, Or an inorganic compound other than silica may be added so as to continuously or intermittently be added while grain growth of the composite oxide fine particles is carried out.

When the molar ratio (M _Ea ) / (M _Sa ) is less than 0.1, the effect of adding the electrolytic salt becomes insufficient, and the amount of the acid salt added in step (e) Is added to remove the at least a portion of the elements other than silicon constituting the composite oxide primary particles, the composite oxide fine particles fail to maintain their spherical shape and are destroyed, making it difficult to obtain the chain-silica hollow fine particles having cavities therein . The reason for the effect of adding such an electrolyte salt is not clear, but it can be considered that the silica on the surface of the particle-grown composite oxide primary particles is increased, and the silica insoluble in the acid acts as a protective film of the composite oxide primary particles .

For this reason, the silica or silica-alumina coating layer is formed in the step (d) to be described later, but the silica or silica-alumina coating layer to be formed may be made thin.

Even if the molar ratio (M _Ea ) / (M _Sa ) exceeds 10, the effect of adding the electrolyte is not improved, and new fine particles are produced or the economical efficiency is lowered.

Step (b)

The primary particle dispersion of the composite oxide prepared in the step (a) is then washed to remove cations, anions, and electrolytes.

The cleaning method is not particularly limited as long as it can remove positive ions, negative ions, and electrolytes, and conventionally known methods can be employed. In the present invention, since the particles are fine, an ultrafiltration membrane method and an ion exchange resin method are suitably employed. Both of them may be used together.

If the washing is insufficient, it is difficult to obtain the chain-like composite oxide primary particles in the next step (c).

Step (c)

An electrolyte is added to the primary particle dispersion of the composite oxide and hydrothermally treated at 50 to 300 캜 and further at 80 to 250 캜 in the presence of the electrolyte to prepare a dispersion of the chain-like composite oxide particles.

The electrolyte is not particularly limited so long as it can chain the composite oxide primary particles. In the present invention, an alkaline earth metal salt is preferable.

Examples of alkaline earth metal salts include hydrochloride, nitrate, sulfate, and organic acid salts such as magnesium and calcium.

The concentration of the primary particle dispersion of the complex oxide when the electrolyte is added is preferably in the range of 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, in terms of solid content.

When the concentration of the primary particle dispersion of the composite oxide is less than 0.1% by weight as the solid content, it can be made into a chain, but the productivity is low. When the concentration of the primary particle dispersion of the composite oxide exceeds 20% by weight as solid content, have.

Further, the addition amount of the electrolyte is, the weight of the composite oxide primary particles in the dispersion liquid _(P1 W) and weight of the electrolyte _(EL W) and the ratio (W _EL / W _P1) is 0.001 to 0.8, and further the range of 0.01 to 0.2 of .

(W _EL ) / (W _P1 ) is less than 0.001, the composite oxide primary particles may not be cured. When (W _EL ) / (W _P1 ) exceeds 0.8, the composite oxide primary particles become aggregates There is a case.

In the present invention, an acidic silicic acid solution may be added to the electrolyte. The acidic silicic acid solution is an acidic silicic acid solution such as an acidic silicic acid solution used in a step (d-2) to be described later, and the amount of the acidic silicic acid solution to be added is such that the weight (W _P1 ) of the composite oxide primary particles in the dispersion, (W _S / W _P 1) to the weight (W _S ) of ₂ is preferably in the range of 0.01 to 1, more preferably 0.02 to 0.5.

(W _S ) / (W _P1 ) of less than 0.01 may not be able to maintain the chain phase of the composite oxide primary particles that accelerate the chain growth or become chain-like, depending on the particle diameter of the composite oxide primary particles. If W _S / W _P1 exceeds 1, it may be difficult to remove elements other than silicon in the step (e) described later. Even if the removal can be made, through holes in which the cavities in the chain- May not be formed.

When the hydrothermal treatment temperature is less than 50 캜, the chain-like phase does not progress and a large number of monodisperse composite oxide primary particles remain, and when the hydrothermal treatment temperature exceeds 300 캜, aggregated particles tend to increase.

On the other hand, the hydrothermal treatment time varies depending on the temperature, but is generally 1 to 24 hours.

Step (d)

Then, a silica or silica-alumina coating layer is formed.

There are three methods for forming the silica or silica-alumina coating layer. The first method is a step (d-1), wherein an aqueous solution of an alkali, an organosilicon compound represented by the following formula (1) and / or a partial hydrolyzate thereof represented by the following formula (1) is added to the dispersion of the striated composite oxide particles obtained in the step .

R _n SiX _(4-n) (One)

R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an acryl group, an epoxy group, a methacryl group, an amino group or a CF ₃ group, X is an alkoxy group having 1 to 4 carbon atoms, a silanol group, , and n is an integer of 0 to 3]

Specific examples of the organic silicon compound include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltri Vinyltriethoxysilane, vinyltris (? Methoxyethoxy) silane, vinyltriethoxysilane, vinyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris , 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane,? - (3,4 epoxycyclohexyl) ethyltrimethoxysilane,? -Glycidyl Butoxycarbonyloxypropyltrimethoxysilane, dodecyltrimethyltrimethoxysilane,? -Glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropyltriethoxysilane,? -Methacryloxypropylmethyldimethoxysilane,? -Methacryloxypropyltrimethoxy Silane,? -Methacryloxypropylmethyl di (Aminoethyl) gamma -aminopropyltrimethoxysilane, N-beta (aminoethyl) gamma -aminopropyltrimethoxysilane, N-beta Aminoethyl)? -Aminopropyltriethoxysilane,? -Aminopropyltrimethoxysilane,? -Aminopropyltriethoxysilane, N-phenyl-? -Aminopropyltrimethoxysilane,? -Mercaptopropyltrimethoxysilane Trimethylsilane, trimethylsilane, trimethylsilanol, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, .

The second method is a step (d-2), wherein an aqueous alkaline solution and an acidic silicic acid solution are added to the dispersion of the stratified composite oxide particles obtained in the step (c).

As the acidic silicic acid solution, an aqueous alkali silicate solution, for example, an acidic silicic acid solution in which water glass is de-alkalized with an ion exchange resin is used. The concentration of the acidic silicic acid solution is in the range of 0.1 to 7% by weight in terms of SiO ₂ and the pH is in the range of 0.1 to 4.

The third method is a step (d-3), wherein an aqueous solution of an alkali silicate and an aqueous solution of an aluminic acid are added to the dispersion of the complex oxide particles obtained in the step (c).

In the above, the amount of the organic silicon compound or the acidic silicic acid solution used for forming the silica coating layer is in the range of 10 to 2000% by weight, more preferably 20 to 1000% by weight, of the solid oxide complex particles as solid components.

When the addition amount of the organosilicon compound or the acidic silicic acid liquid is less than 10% by weight of the solid-phase composite oxide particles as the solid content, since the coating layer is thin, when the elements other than silicon are removed in step (e) Or may be a chain-like silica-based hollow fine particle having a cavity open to the outside.

If the addition amount of the organosilicon compound or the acidic silicic acid solution is more than 2000% by weight of the solid-phase composite oxide particles as solids, it becomes difficult to remove elements other than silicon or the shell is too thick to obtain chain silica fine hollow fine particles having a desired low refractive index There is no case.

The addition of the alkali aqueous solution is preferably carried out so that the pH of the dispersion of the chain-like composite oxide particles is maintained at 7 to 13.5, and more preferably at 10 to 13. [

When the pH of the dispersion of the chain-like composite oxide particles is less than 7, the chain-like composite oxide particles aggregate to form a uniform coating layer and the particles can not be grown.

When the pH of the dispersion of the chain-like composite oxide particles is more than 13.5, the silica and alumina layers are difficult to form due to the high solubility of silica and alumina, and the desired chain-silica hollow microparticles can not be obtained have.

When an alkali silicate aqueous solution and an aqueous aluminic acid solution are added to form the silica-alumina coating layer in the step (d-3), the molar ratio Al ₂ O ₃ / SiO ₂ ranges from 0.01 to 0.5, more preferably from 0.05 to 0.3 .

When the molar ratio Al ₂ O ₃ / SiO ₂ is less than 0.01, there is no difference from the case where the silica layer is formed, and the ease of removal of elements other than silicon due to the formation of the silica-alumina coating layer deteriorates.

When the molar ratio Al ₂ O ₃ / SiO ₂ exceeds 0.5, alumina in the coating layer is too much, and when the elements other than silicon are removed in the step (e), the coating layer can not be maintained, Based hollow microparticles.

When adding an aqueous solution of an alkali silicate and an aqueous solution of an aqueous solution of alumina to form a silica-alumina coating layer, the addition amount is preferably in the range of 10 to 2000% by weight, more preferably 20 to 1000% by weight, of the solid- .

When the addition amount of the aqueous solution of the silicate acid and the aqueous solution of the aluminic acid is less than 10% by weight based on the solid composite oxide particle as the solid content, the coating layer is thin, so that in the step (e), when the elements other than silicon are removed, Collapse, or chain-silica-based hollow fine particles having cavities open to the outside.

If the added amount of the aqueous solution of the silicate acid and the aqueous solution of the aluminic acid exceeds 2,000% by weight of the solid-state composite oxide particles as the solid content, it becomes difficult to remove the elements other than silicon or the outer shell is too thick to obtain the desired chain-silica hollow fine particles having a low refractive index There is no case.

The concentration of the dispersion of the chain-like composite oxide particles in the formation of the silica layer and the silica-alumina layer is preferably in the range of 0.5 to 20% by weight, more preferably 1 to 10% by weight, in terms of solid content.

When the concentration of the dispersion of the complex oxide particles is less than 0.5% by weight, the productivity is low. When the concentration is more than 20% by weight, the particles may become aggregated.

The temperature at which the silica or silica-alumina coating layer is formed is usually in the range of 30 to 150 캜, more preferably 50 to 100 캜.

When the temperature at the time of forming the silica or silica-alumina coating layer is less than 30 占 폚, the formation of the silica-alumina coating layer may require a long time or a coating layer having a desired thickness may not be formed.

When the temperature at the time of forming the silica or silica-alumina coating layer exceeds 150 캜, the chain-like composite oxide particles may aggregate depending on the concentration.

Step (e)

An acid is added to the dispersion of silica or silica-alumina coated composite oxide particles to remove at least a part of elements other than silicon constituting the silica or silica-alumina-coated composite oxide particles to obtain a chain silica-based hollow fine particle dispersion.

When the element other than silicon is removed, for example, it is dissolved or removed by adding a mineral acid or an organic acid, or by ion exchange with the cation exchange resin, or by combining these methods.

The concentration of silica or silica-alumina coated composite oxide particles in the dispersion of silica or silica-alumina coated composite oxide particles when removing elements other than silicon varies depending on the treatment temperature, but is preferably 0.1 to 50% by weight, Particularly preferably 0.5 to 25% by weight. When the concentration of the silica-coated composite oxide particles is less than 0.1 wt%, the production efficiency is low. When the concentration of the silica-coated composite oxide particles is more than 50 wt%, the composite oxide particles having a large content of elements other than silicon can be uniformly or efficiently removed There is no case.

The removal of the element is preferably carried out until the MO _x / SiO ₂ of the chain-silica hollow microparticles obtained by the above-mentioned reason is 0.0001 to 0.2, particularly 0.0001 to 0.1.

Step (f)

The chain-silica hollow microparticle dispersion obtained in the step (e) mainly contains acid, cations of elements other than silicon, and dissolved silica, and therefore, these are washed and removed.

The cleaning method is the same as the step (b). The degree of washing is preferably carried out until the acid, the cation of the element other than silicon, and the dissolved silica substantially disappear.

Process (g)

The chain-silica-based hollow fine particle dispersion is hydrothermally treated at 50 to 300 캜, more preferably at 80 to 250 캜.

In the present invention, the chain-silica-based hollow fine particles obtained in the step (f) can be used as they are, but it is preferable to carry out the hydrothermal treatment following the step (f).

If the hydrothermal treatment temperature is less than 50 캜, the obtainable outline of the chain-silica-based hollow fine particles becomes insufficient, and depending on the use of the chain-like silica-based hollow fine particles, the solvent or the matrix- And the effect of low refractive index can not be obtained in some cases. Further, the content of impurities such as alkali metals or ammonia in the obtainable chain silica fine particles can not be effectively reduced, the stability of the coating liquid for forming a film becomes insufficient, and the strength of the coat obtained thereby becomes insufficient .

When the hydrothermal treatment temperature exceeds 300 캜, the chain-like silica-based hollow fine particles may be aggregated.

After the hydrothermal treatment, it may be washed as required in the above-mentioned step (b).

By washing, the alkali and / or ammonia eluted by the hydrothermal treatment can be further reduced.

On the other hand, in the production method of the chain-silica hollow microparticles of the present invention, the organic solvent-dispersed sol can be obtained by substituting the obtained chain-silica fine hollow microparticle dispersion with an organic solvent using an ultrafiltration membrane, a rotary evaporator or the like.

The obtained chain-silica hollow fine particles may be treated by a silane coupling agent or the like by a conventionally known method.

Further, in the production method of the chain-silica-based hollow fine particles of the present invention, it is possible to carry out cleaning, drying and firing as required.

[Coating liquid for forming a transparent film]

Next, the coating liquid for forming a transparent film will be described.

The coating liquid for forming a transparent coating film according to the present invention contains the above chain-like silica-based hollow fine particles and a matrix-forming component.

Distribution dealer

As the dispersion medium of the coating liquid, conventionally known dispersion media can be used. Specifically, water and various organic solvents can be mentioned.

The organic solvent used in the present invention is not particularly limited as long as it can dissolve or disperse a matrix forming component and a polymerization initiator to be used, which will be described later, and can disperse the above-mentioned chain-like silica hollow fine particles uniformly. Can be used.

Specific examples thereof include alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydroperfuryl alcohol, ethylene glycol, hexylene glycol and isopropyl glycol; Esters such as methyl acetate, ethyl acetate, and butyl acetate; Diethyl ether, ethylene glycol monomethyl ether, ethylene glycol mono ether, ethylene glycol monobutyl ether, ethylene glycol isopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol mono Ethers such as ethyl ether; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl ketone, cyclohexanone, methylcyclohexanone, dipropyl ketone, methyl pentyl ketone, diisobutyl ketone, isophorone, acetylacetone, Toluene, xylene, and the like. These may be used alone or in combination of two or more.

Polymerization initiator

In the coating liquid of the present invention, the chain-like silica-based hollow fine particles and the matrix forming component may be contained together with a polymerization initiator. As the polymerization initiator, known ones can be used without particular limitation, and examples thereof include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) Methyl-2-methyl-phenyl-propane-1-ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, and the like.

Chain silica-based hollow fine particles

As the chain-silica-based hollow fine particles, the chain-like silica hollow fine particles are used.

In the coating liquid of the present invention, inorganic oxide fine particles other than the chain-like silica-based hollow fine particles may be contained, if necessary.

Examples of the inorganic oxide fine particles include conventionally known low refractive index inorganic oxide fine particles, high refractive index inorganic oxide fine particles, and conductive inorganic oxide fine particles.

The matrix-forming component is a dispersion of the above-mentioned fine particles, refers to a component capable of forming a film on the surface of the substrate, and can be selected from resins suitable for conditions such as adhesion with a substrate, hardness, For example, it is possible to use conventional resins such as polyester resin, acrylic resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluorine resin, silicone resin, butyral resin, phenol resin, vinyl acetate resin, A resin for coating such as a copolymer or a modified product of these resins, a hydrolyzable organosilicon compound such as alkoxysilane, and a partial hydrolyzate thereof, etc. .

The total concentration of the matrix-forming component of the coating liquid for forming a transparent coating film and the chain-like silica-based hollow microparticles is preferably in the range of 1 to 60% by weight, more preferably 2 to 50% by weight,

When the solid content concentration of the coating liquid for forming a transparent coating film is less than 1% by weight, it is not always possible to obtain a necessary film thickness in one application, and therefore repeated application and drying may result in insufficient adhesion, It is disadvantageous.

If the solid content exceeds 60% by weight, the obtained transparent coating film may have a non-uniform thickness or cracks may be generated.

The concentration of the chain-like silica-based hollow fine particles in the coating liquid for forming a transparent film is such that the content of the chain-like silica-based hollow fine particles in the obtainable transparent coating is in the range of 5 to 80% by weight, more preferably 10 to 50% Use it as much as possible.

When the content of the chain-like silica-based hollow microparticles in the transparent coating film is less than 5% by weight as solid content, a transparent coating film having a desired low refractive index can not be obtained. In addition, Known low refractive index particles may be used.

When the content of the chain-like silica-based hollow microparticles in the transparent coating film exceeds 80% by weight as solid content, the transparency and strength of the film may become insufficient.

On the other hand, when inorganic oxide fine particles other than the chain-silica hollow fine particles are used as required, the total concentration of the particles is preferably in the same range as described above.

The concentration of the matrix forming component in the coating liquid for forming a transparent coating film is used so that the content of the matrix component in the obtained transparent coating film is in the range of 20 to 95% by weight, more preferably 50 to 90% by weight, as solid content.

More specifically, the concentration of the chain-like silica-based hollow fine particles in the coating liquid for forming a transparent coating film is preferably in the range of 0.05 to 48% by weight, more preferably 0.1 to 30% by weight, as solid content.

The concentration of the matrix forming component in the coating liquid for forming a transparent film is preferably in the range of 0.2 to 57% by weight, more preferably 0.5 to 54% by weight, as solid content.

The above-mentioned coating liquid for forming a transparent film is applied to a substrate by a known method such as a dipping method, a spraying method, a spinner method, a roll coating method, a bar coating method, a gravure printing method, a micro gravure printing method, The transparent coating can be formed by curing by a usual method such as heat treatment.

The film thickness of the obtained transparent coating film is preferably in the range of 200 nm to 20 占 퐉.

[Apparatus with transparent coating film]

Next, the transparent-film-attached substrate will be described.

The transparent film-coated base material according to the present invention is formed on the base material surface with a transparent film formed using the above-mentioned transparent film-forming coating liquid, alone or in combination with another film.

materials

Examples of the substrate include a substrate such as a glass sheet, a polycarbonate sheet, an acrylic resin sheet, a plastic sheet such as PET or TAC, a plastic film, a substrate such as a plastic lens or a plastic panel, a cathode ray tube, a fluorescent display tube, A coating film, a hard coat film, a flattening film, a high refractive index film, an insulating film, a conductive resin film, a conductive metal fine particle film, a conductive metal oxide fine particle film, A primer film, or the like. On the other hand, when used in combination, the coating of the present invention is preferably formed on the outermost surface.

The transparent coating film may be formed by applying the coating liquid for forming a transparent coating film to a substrate by a known method such as a dipping method, a spraying method, a spinner method or a roll coating method, drying it, and optionally curing .

The refractive index of the transparent coating formed on the surface of the substrate varies depending on the mixing ratio of the chain-like silica-based hollow fine particles and the matrix component and the refractive index of the matrix to be used, but is in the range of 1.15 to 1.42 and has a low refractive index. On the other hand, the refractive index of the chain-silica-based hollow fine particles of the present invention is 1.10 to 1.35.

This is because the chain-silica hollow microparticles of the present invention have cavities therein, and the matrix-forming component such as resin remains outside the particles, and cavities in the chain silica-based hollow microparticles are retained.

When the refractive index of the base material is 1.60 or less, the coating film having a refractive index of 1.60 or more (hereinafter sometimes referred to as an intermediate film) is formed on the surface of the base material, It is recommended to form a transparent coating film containing a chain-like silica-based hollow fine particle. When the refractive index of the intermediate coating film is 1.60 or more, the difference from the refractive index of the transparent coating film containing the chain silica-based hollow fine particles of the present invention is large, so that a substrate with a transparent coating film excellent in antireflection performance can be obtained. The refractive index of the intermediate coat can be adjusted by the refractive index of the metal oxide fine particles used for increasing the refractive index of the intermediate coat, the mixing ratio of the metal oxide fine particles and the resin, and the refractive index of the resin to be used.

The coating liquid for film formation of the intermediate coat is a mixture of metal oxide particles and a film-forming matrix, and an organic solvent is mixed if necessary. As the film-forming matrix, the same film as the film containing the silica-based fine particles of the present invention can be used. By using the same film-forming matrix, a film-attached base material having excellent adhesion between both films can be obtained.

The present invention will be described in more detail with reference to the following examples.

≪ Example 1 >

Preparation of chain-like silica-based hollow fine particles (P-1)

100 g of silica-alumina sol {USBB-120, average particle diameter 25 nm, SiO _2. Al ₂ O ₃ concentration 20 wt.%, Solid content Al ₂ O ₃ content 27 wt.%, Product of NIKKISOKUBA CHEMICAL Co., (純水) was added to 3900g, the temperature was increased to 98 ℃, while maintaining this temperature, the sodium aluminate aqueous solution of 1750g of a 1.5% silicic acid concentration of 0.5 weight% as sodium 1750g and Al ₂ O ₃ concentration of 6 as SiO ₂ Hour to obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion. At this time, the molar ratio MO _X / SiO ₂ was 0.2. The pH of the reaction solution at this time was 12.0. The average primary particle diameter of this dispersion was 35 nm. (Step (a))

Subsequently, the SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion was washed with an ultrafiltration membrane method and concentrated to obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion having a solid concentration of 5 wt% . (Step (b))

Separately, an aqueous solution was prepared by mixing 136 g of an acidic silicic acid solution having a concentration of 2% by weight as SiO ₂ and 5.4 g of an aqueous solution of Ca (NO ₃ ) _{2 with} a concentration of 10% by weight as an electrolyte for chain formation. SiO ₂ · Al ₂ O ₃ by mixing the primary particles (P-1) dispersion liquid 300g, was added an aqueous NaOH solution 9g of the concentration of 2% by weight thereto, subjected to 3 hours heat treatment at 150 ℃, solid content concentration of 5% by weight Chain complex oxide particle (P-1) dispersion was prepared. It was then cooled to room temperature. The pH of the dispersion at this time was 10.9. (Step (c))

Then, by adding pure water 3900g to a solid concentration of 5% of the chain complex oxide particles (P-1) dispersion liquid 300g weight, the temperature was increased to 98 ℃, while maintaining this temperature, aqueous solution of sodium silicate 1530g of a 1.5% by weight in terms of SiO ₂ concentration, and 500 g of a sodium aluminate aqueous solution having a concentration of 0.5% by weight as Al ₂ O ₃ was added over 17 hours to obtain a silica-alumina coated complex oxide particle (P-1) dispersion. (Step (d))

Subsequently, 1,125 g of pure water was added to 500 g of the silica-alumina coated complex oxide particle (P-1) dispersion which had been washed with the ultrafiltration membrane method and concentrated to have a solid content concentration of 13% by weight. Subsequently, concentrated hydrochloric acid (concentration 35.5% Was added dropwise to adjust the pH to 1.0, and the dealumination treatment was carried out. Subsequently, the dissolved aluminum salt was separated and washed with an ultrafiltration membrane while adding 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, to obtain an aqueous dispersion of chain-silica hollow fine particles (P-1) having a solid concentration of 20% by weight. (Step (e)) (Step (f))

Average length, average length, outer thickness, average diameter of through holes, MO _x / SiO ₂ (molar ratio) and refractive index were measured for the obtained chain-like silica hollow microparticles (P-1). The same measurements were also made in the following examples and comparative examples, and the results are shown in Table 1.

Here, the average particle diameter was measured by a dynamic light scattering method, and the refractive index was measured by the above-described method using Series A and AA of CARGILL as a standard refractive solution. MO _x was measured by an ICP emission spectrochemical analyzer (Shimadzu Seisakusho, ICPS-8100), SiO ₂ was obtained by removing the weight of MO _x and Na ₂ O from the weight of the remaining solid content when firing at 1000 ° C Respectively.

Production of transparent film-coated substrate (A-1)

The aqueous dispersion of the chain silica-based hollow fine particles (P-1) having a solid concentration of 20% by weight obtained above was replaced with ethanol by using an ultrafiltration membrane to obtain a chain silica fine hollow fine particle having a solid concentration of 20% -1) was prepared.

50 g of the dispersion in which the alcohol dispersion of the chain-like silica hollow fine particles (P-1) was diluted with ethanol to a solid concentration of 5% by weight, 3 g of acrylic resin {Hytaloid 1007, manufactured by Hitachi Kasei Co., (Weight ratio) mixed solvent was sufficiently mixed to prepare a coating liquid.

This coating liquid was applied to a PET film by a bar coater method and dried at 80 DEG C for 1 minute to obtain a transparent film-coated base material (A-1) having a transparent coating film thickness of 100 nm. Table 2 shows the total light transmittance, haze, reflectance of light rays at a wavelength of 550 nm, refractive index of the coating film, adhesion, scratch resistance and pencil hardness of the transparent film-coated base material (A-1). The same measurements were also made in the following examples and comparative examples, and the results are shown in Table 2.

The total light transmittance and haze were measured with a haze meter (manufactured by Suga Test Instruments Co., Ltd.) and a reflectance was measured with a spectrophotometer (Nihon Bunkha, Ubest-55, respectively). The refractive index of the coating film was measured by an Ellipsometer (manufactured by ULVAC, EMS-1). On the other hand, the uncoated PET film had a total light transmittance of 90.7%, a haze of 2.0%, and a reflectance of 7.0% of a light beam having a wavelength of 550 nm.

The pencil hardness was measured by 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 surface of the film, and a predetermined weight was applied and pulled at a constant speed to observe the presence of a wound.

In addition, 11 parallel wounds were stuck on the surface of the transparent film-coated base material (A-1) with a knife at intervals of 1 mm in width and 100 squares were formed, a cellophane tape was adhered thereto, and then the cellophane tape was peeled off The adhesion was evaluated by classifying the number of remaining squares in which the film was not peeled off in the following three stages.

Number of remaining boxes: 90 or more: ◎

Number of remaining boxes: 85 ~ 89: ○

Number of remaining squares 84 or less: △

The scratch resistance was evaluated by the following criteria by observing the surface of the film with eyes using # 0000 steel wool and sliding it 50 times under a load of 500 g / cm 2.

The wounds of the muscles are not recognized: ◎

A little bit of wounds are recognized: ○

A lot of wounds are recognized at the end: △

The face is entirely trimmed: x

≪ Example 2 >

Preparation of chain-silica-based hollow fine particles (P-2)

An aqueous dispersion of the chain-silica-based hollow microparticles (P-2) having a solid concentration of 20% by weight was obtained in the same manner as in Example 1 except that 2.7 g of an aqueous solution of Ca (NO ₃ ) _{2 having} a concentration of 10% .

Preparation of transparent film-coated substrate (A-2)

A transparent coating film-coated substrate (A-1) having a coating liquid and a transparent coating film thickness of 100 nm was prepared in the same manner as in Example 1 except that an aqueous dispersion liquid of chain-silica-based hollow microparticles (P-2) having a solid concentration of 20% 2).

≪ Example 3 >

Preparation of Chain Silica-Based Hollow Fine Particles (P-3)

An aqueous dispersion of chain-silica-based hollow microparticles (P-3) having a solid concentration of 20% by weight was obtained in the same manner as in Example 1 except that 54 g of a Ca (NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight was mixed as an electrolyte.

Production of transparent film-coated base material (A-3)

A transparent coating film-adhered base material (A-3) having a film thickness of 100 nm and a coating liquid and a transparent coating film were prepared in the same manner as in Example 1, except that the aqueous dispersion liquid of the chain-silica-based hollow microparticles (P- 3).

<Example 4>

Stretch  Preparation of silica-based hollow fine particles (P-4)

An aqueous dispersion of chain-silica-based hollow microparticles (P-4) having a solid concentration of 20% by weight was obtained in the same manner as in Example 1 except that 4.9 g of Mg (NO ₃ ) ₂ aqueous solution of 10 wt% .

Preparation of transparent film-coated substrate (A-4)

A transparent coating film-adhered base material (A-1) having a film thickness of 100 nm and a coating liquid and a transparent coating film was prepared in the same manner as in Example 1, except that the aqueous dispersion of chain-silica fine hollow particles (P-4) having a solid concentration of 20% 4).

&Lt; Example 5 >

Preparation of chain-silica-based hollow fine particles (P-5)

100 g of silica-alumina sol {USBB-120, average particle diameter 25 nm, SiO _2. Al ₂ O ₃ concentration 20 wt.%, Solid content Al ₂ O ₃ content 27 wt.%, Product of NIKKISOKUBA CHEMICAL Co., 405 g of a sodium silicate aqueous solution having a concentration of 1.5% by weight and 405 g of an aqueous sodium aluminate solution having a concentration of 0.5% by weight as Al ₂ O ₃ as SiO ₂ were added over 6 hours while maintaining the temperature at 98 ° C, To obtain a dispersion of SiO ₂ Al ₂ O ₃ primary particles (P-5). At this time, the molar ratio MO _X / SiO ₂ was 0.2. The pH of the reaction solution at this time was 12.0. The average primary particle diameter of the dispersion was 28 nm. (Step (a))

Subsequently, the dispersion of SiO ₂ Al ₂ O ₃ primary particles (P-5) was washed with an ultrafiltration membrane method and concentrated to obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-5) dispersion having a solid concentration of 5 wt% . (Step (b))

Separately, an aqueous solution was prepared by mixing 136 g of an acidic silicic acid solution having a concentration of 2% by weight as SiO ₂ and 5.4 g of an aqueous solution of Ca (NO ₃ ) _{2 with} a concentration of 10% by weight as an electrolyte for chain formation. (P-5) dispersion liquid of SiO ₂ .Al ₂ O ₃ primary particles (P-5) were mixed, and 9 g of a NaOH aqueous solution of 2 wt% in concentration was added thereto and then hydrothermally treated at 150 ° C. for 3 hours to obtain a Chain complex oxide particle (P-5) dispersion was prepared. It was then cooled to room temperature. The pH of the dispersion at this time was 10.9. (Step (c))

Then, by adding pure water 3900g to a solid concentration of 5% of the chain complex oxide particles (P-5) dispersion liquid 300g weight, the temperature was increased to 98 ℃, while maintaining this temperature, aqueous solution of sodium silicate 1530g of a 1.5% by weight in terms of SiO ₂ concentration, and 500 g of a sodium aluminate aqueous solution having a concentration of 0.5% by weight as Al ₂ O ₃ was added over 17 hours to obtain a silica-alumina coated complex oxide particle (P-5) dispersion. (Step (d))

Subsequently, 1,125 g of pure water was added to 500 g of the silica-alumina coated complex oxide particle (P-5) dispersion which had been washed with the ultrafiltration membrane method and concentrated to have a solid content concentration of 13% by weight. Subsequently, concentrated hydrochloric acid (concentration: 35.5% Was added dropwise to adjust the pH to 1.0, and a dealumination treatment was carried out. Subsequently, the dissolved aluminum salt was separated and washed with an ultrafiltration membrane while adding 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water to obtain an aqueous dispersion of chain-silica hollow fine particles (P-5) having a solid concentration of 20% by weight. (Step (e)) (Step (f))

Production of transparent film-coated substrate (A-5)

A transparent coating film-coated substrate (A-1) having a coating liquid and a transparent coating film thickness of 100 nm was prepared in the same manner as in Example 1 except that an aqueous dispersion of chain-silica fine hollow particles (P-5) having a solid concentration of 20% 5).

&Lt; Example 6 >

Stretch  Preparation of silica-based hollow fine particles (P-6)

100 g of silica-alumina sol {USBB-120, average particle diameter 25 nm, SiO _2. Al ₂ O ₃ concentration 20 wt.%, Solid content Al ₂ O ₃ content 27 wt.%, Product of NIKKISOKUBA CHEMICAL Co., 20,900 g of a sodium silicate aqueous solution having a concentration of 1.5% by weight and 20,900 g of an aqueous sodium aluminate solution having a concentration of 0.5% by weight as Al ₂ O ₃ as SiO ₂ were added to the mixture at a temperature of 98 캜 for 6 hours To thereby obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-6) dispersion. At this time, the molar ratio MO _X / SiO ₂ was 0.2. The pH of the reaction solution at this time was 12.0. The average primary particle diameter of this dispersion was 70 nm. (Step (a))

Subsequently, the SiO ₂ · Al ₂ O ₃ primary particle (P-6) dispersion was washed with an ultrafiltration membrane method and concentrated to obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-6) dispersion having a solid concentration of 5 wt% . (Step (b))

Separately, an aqueous solution was prepared by mixing 136 g of an acidic silicic acid solution having a concentration of 2% by weight in SiO ₂ and 5.4 g of a Ca (NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte for chain formation. (P-6) dispersion liquid of SiO ₂ Al ₂ O ₃ primary particles (P-6) were mixed, 9 g of NaOH aqueous solution having a concentration of 2% by weight was added thereto and then subjected to hydrothermal treatment at 150 ° C. for 3 hours to obtain a Chain complex oxide particle (P-6) dispersion was prepared. It was then cooled to room temperature. The pH of the dispersion at this time was 10.9. (Step (c))

The temperature is then raised by adding 3900g of pure water to a solid concentration of 5% of the chain complex oxide particles (P-6) dispersion liquid 300g weight to 98 ℃, while maintaining this temperature, aqueous solution of sodium silicate as SiO ₂ concentration of 1.5% by weight of 2,000g And 700 g of an aqueous sodium aluminate solution having a concentration of 0.5% by weight as Al ₂ O ₃ were added over 17 hours to obtain a silica-alumina coated complex oxide particle (P-6) dispersion. (Step (d))

Subsequently, 1,125 g of pure water was added to 500 g of the silica-alumina coated complex oxide particle (P-6) dispersion which had been washed with the ultrafiltration membrane method and concentrated to have a solid concentration of 13% by weight, and then concentrated hydrochloric acid (concentration 35.5% by weight) Was added dropwise to adjust the pH to 1.0, and a dealumination treatment was carried out. Subsequently, the dissolved aluminum salt was separated and washed with an ultrafiltration membrane while 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added to obtain an aqueous dispersion of chain-silica hollow fine particles (P-6) having a solid concentration of 20% by weight. (Step (e)) (Step (f))

Production of transparent film-coated base material (A-6)

A transparent coating film-coated substrate (A-1) having a coating liquid and a transparent coating film thickness of 100 nm was prepared in the same manner as in Example 1, except that an aqueous dispersion of chain-silica fine hollow particles (P-6) having a solid concentration of 20% 6).

&Lt; Example 7 >

Preparation of transparent film-coated substrate (A-7)

36.6 g of a dispersion in which the alcohol dispersion of the chain-like silica-based hollow microparticles (P-1) was diluted to an ethanol solid concentration of 5% by weight in Example 1 and 36.6 g of an acrylic resin {Hitaloid 1007, product of Hitachi Kasei Co., (A-7) having a coating liquid and a transparent coating film thickness of 100 nm was obtained in the same manner as in the coating solution (A-7) except that 58 g of a mixed solvent of isopropanol and n-butanol in 1/1 (weight ratio)

&Lt; Example 8 >

Production of transparent film-coated base material (A-8)

55 g of a dispersion in which the alcohol dispersion of the chain-like silica-based hollow microparticles (P-1) was diluted with ethanol to a solid concentration of 5% by weight and the acrylic resin {Hitaloid 1007, product of Hitachi Chemical Co., Ltd.} 2.75 (A-8) having a coating liquid and a transparent coating film thickness of 100 nm were obtained in the same manner as in Example 1, except that 43.1 g of a mixed solvent of isopropanol and n-butanol in 1/1 (weight ratio) was used.

&Lt; Example 9 >

Preparation of Chain Silica-Based Hollow Fine Particles (P-7)

(Concentration: 35.5% by weight) was added dropwise to 500 g of the dispersion of silica-alumina coated complex oxide particles (P-1) having a solid content concentration of 13% by weight by washing with an ultrafiltration membrane method and concentrating. To adjust the pH to 0.5, and then dealumination treatment was carried out. Subsequently, the dissolved aluminum salt was separated and washed with an ultrafiltration membrane while 25 L of a hydrochloric acid aqueous solution of pH 3.0 and 10 L of pure water were added to obtain an aqueous dispersion of chain-silica hollow fine particles (P-7) having a solid concentration of 20% by weight. (Step (e)) (Step (f))

Production of transparent film-coated substrate (A-9)

A transparent coating film-coated base material (A-1) having a coating liquid and a transparent coating film thickness of 100 nm was prepared in the same manner as in Example 1, except that an aqueous dispersion of chain silica-based hollow fine particles (P-7) having a solid concentration of 20% 9).

&Lt; Comparative Example 1 &

Preparation of silica-based hollow fine particles (RP-1)

100 g of silica-alumina sol {USBB-120, average particle diameter 25 nm, SiO _2. Al ₂ O ₃ concentration 20 wt.%, Solid content Al ₂ O ₃ content 27 wt.%, Product of NIKKISOKUBA CHEMICAL Co., 1700 g of a sodium silicate aqueous solution having a concentration of 1.5% by weight and 1750 g of an aqueous sodium aluminate solution having a concentration of 0.5% by weight as Al ₂ O ₃ as SiO ₂ were added over 6 hours while maintaining the temperature at 98 ° C. To obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion. At this time, the molar ratio MO _X / SiO ₂ was 0.2. The pH of the reaction solution at this time was 12.0. The average primary particle diameter of this dispersion was 35 nm. (Step (a))

Subsequently, the SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion was washed with an ultrafiltration membrane method and concentrated to obtain a SiO ₂ · Al ₂ O ₃ primary particle (P-1) dispersion having a solid concentration of 5 wt% . (Process (b))

Then, by adding pure water 3900g to a solid concentration of 5% by weight of SiO ₂ · Al ₂ O ₃ primary particles (P-1) dispersion liquid 300g, the temperature was increased to 98 ℃, while maintaining this temperature, 1.5% by weight concentration as SiO ₂ 1530 g of sodium silicate aqueous solution and 500 g of sodium aluminate aqueous solution having a concentration of 0.5% by weight as Al ₂ O ₃ were added over 17 hours to obtain a dispersion of silica-alumina coated composite oxide particles (RP-1).

Subsequently, 1,125 g of pure water was added to 500 g of the silica-alumina coated composite oxide particle (RP-1) dispersion which had been washed with the ultrafiltration membrane method and concentrated to have a solid content concentration of 13% by weight and then concentrated hydrochloric acid (concentration 35.5% by weight) The pH was adjusted to 1.0 by dropwise addition, and the dealumination treatment was carried out. Subsequently, the dissolved aluminum salt was separated and washed with an ultrafiltration membrane while 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added to obtain an aqueous dispersion of monodispersed silica-based hollow fine particles (RP-1) having a solid concentration of 20% by weight. The silica-based hollow fine particles (RP-1) in the aqueous dispersion did not coagulate or aggregate.

Preparation of transparent film-coated substrate (RA-1)

Except that the coating liquid and the transparent coating film-coated substrate (RA-1) having a thickness of 100 nm were used in the same manner as in Example 1 except that an aqueous dispersion of silica-based hollow fine particles (RP-1) having a solid concentration of 20% ).

&Lt; Comparative Example 2 &

Preparation of chain-silica-based hollow fine particles (RP-2)

Step (c) was carried out in the same manner as in Example 1 except that 140 g of Ca (NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight was mixed as an electrolyte. At this time, since the agglomerated particles could be obtained, the subsequent step was not carried out.

&Lt; Comparative Example 3 &

Preparation of chain silica-based hollow fine particles (RP-3)

An aqueous dispersion of chain-silica-based hollow microparticles (RP-3) having a solid concentration of 20% by weight was obtained in the same manner as in Example 1 except that 0.1 g of Ca (NO ₃ ) ₂ aqueous solution of 10 wt% . However, most of them were monodisperse silica-based hollow fine particles as in Comparative Example 1. [ The properties of some of the chain-like silica hollow fine particles (RP-3) were measured as in Example 1, and the results are shown in Table 1.

Preparation of transparent film-coated substrate (RA-3)

Except that the aqueous dispersion of the chain-silica fine hollow particles (RP-3) having a solid concentration of 20% by weight was used in Example 1 to prepare a coating liquid and a transparent coating film- 3).

&Lt; Comparative Example 4 &

A transparent film-adhered substrate ( RA -4)

Silica sol (trade name: Catalyst-SI-45P, average particle diameter 45 nm, SiO ₂ concentration 40% by weight, manufactured by Nippon Shokubai Chemical Co., Ltd.) was replaced with ethanol by using an ultrafiltration membrane at a solid concentration of 5% &Lt; / RTI &gt; was prepared.

50 g of a silica organosol sol having a solid concentration of 5% by weight, 3 g of an acrylic resin (Hitaltoid 1007, manufactured by Hitachi Chemical Co., Ltd.) and 47 g of a mixed solvent of isopropanol and n-butanol 1/1 (weight ratio) Was prepared.

This coating liquid was applied to a PET film by a bar coater method and dried at 80 DEG C for 1 minute to obtain a transparent film-coated base material (RA-4) having a transparent coating film thickness of 100 nm.

[Table 1]

[Table 2]

Claims (12)

Based hollow fine particles having an outer shell on the outer side and silica-based hollow fine particles (primary particles) having cavities therein connected in a chain,
Wherein the average length (L) is in a range of 20 to 1500 nm, the average width (W) is in a range of 10 to 300 nm, the refractive index is 1.10 To 1.35 and the ratio (D _S / W) of the average diameter (D _S ) of the through holes to the average width (W) is in the range of 0.1 to 0.9. . The method according to claim 1,
Wherein the outer wall thickness T _S is in the range of 2 to 100 nm and the ratio (T _S / W) of the outer wall thickness to the average width W is in the range of 0.05 to 0.30. 3. The method according to claim 1 or 2,
The chain-like silica hollow microparticles are composed of inorganic oxides other than silica and silica, and the molar ratio (MO _x / SiO ₂ ) of the inorganic oxides other than silica in terms of MO _x is in the range of 0.0001 to 0.2 Chain hollow silica fine particles. (a) an aqueous alkaline solution in which seed particles (seed particles) having a solid concentration in a range of 0.01 to 2% by weight are dispersed in an aqueous alkaline solution, at least one of an aqueous solution of silicate and a solution of an acidic silicic acid, Soluble inorganic compound aqueous solution at the same time to obtain a composite oxide having a molar ratio A [= MO _X / SiO ₂ , when silica is represented by SiO ₂ and an inorganic oxide other than silica is represented by MO _x ] A step of preparing a primary particle dispersion,
(b) cleaning the primary particle dispersion;
(c) subjecting the washed primary particle dispersion liquid to hydrothermal treatment at 50 to 300 占 폚 in the presence of an electrolyte to prepare a dispersion of the chain-like composite oxide particles to which the primary particles of the composite oxide are connected in a chain-
(d) a step of forming a silica coating layer or a silica-alumina coating layer on the surface of the chain-like composite oxide particle to prepare a dispersion of the chain-like composite oxide particles having a coating layer,
(e) adding an acid to the dispersion of the chain-like composite oxide particles having the coating layer to remove at least a part of the elements other than silicon constituting the primary particles of the composite oxide to prepare a dispersion of chain-silica-based hollow fine particles;
(f) cleaning the dispersion of the chain-silica hollow fine particles
Based hollow microparticles. 5. The method of claim 4,
Wherein the alkaline earth metal salt is added as the electrolyte in the step (c). 5. The method of claim 4,
Following step (f) above,
(g) hydrothermally treating the dispersion of the chain-silica fine hollow microparticles in the range of 50 to 300 占 폚. 5. The method of claim 4,
Wherein the element other than silicon is removed in the step (e) until the molar ratio A (= MO _x / SiO ₂ ) is in the range of 0.0001 to 0.2. 8. The method according to any one of claims 4 to 7,
In the step (d), an alkali aqueous solution and an organic silicon compound represented by the following formula (1) and / or a partial hydrolyzate thereof are added to the dispersion of the complex oxide particles obtained in the step (c) Wherein the silica coating layer is formed on the composite oxide particle.
R _n SiX _(4-n) (One)
R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an acryl group, an epoxy group, a methacryl group, an amino group or a CF ₃ group, X is an alkoxy group having 1 to 4 carbon atoms, a silanol group, , and n is an integer of 0 to 3] 8. The method according to any one of claims 4 to 7,
Characterized in that, in the step (d), an alkali aqueous solution and an acidic silicic acid solution are added to the dispersion of the steric complex oxide particles obtained in the step (c), and a silica coating layer is formed on the steric complex oxide particle (METHOD FOR MANUFACTURING HOLE FINE PARTICLE. 8. The method according to any one of claims 4 to 7,
Characterized in that, in the step (d), an alkali silicate aqueous solution and an aqueous aluminic acid solution are added to the dispersion of the stratiform composite oxide particles obtained in the step (c), and a silica-alumina clad layer is formed on the chain- Based hollow microparticles. A coating liquid for forming a transparent film, comprising the chain-silica-based hollow fine particles according to claim 1 and a matrix-forming component. A transparent film-attached substrate having a transparent film formed using the coating liquid for forming a transparent film according to claim 11, either alone or in combination with another film, on the surface of the substrate.

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