TWI510434B - A chain-like silica-based hollow fine particles and a method for producing the same, a coating liquid for forming a transparent film containing the fine particles, and a substrate coated with a transparent film - Google Patents

Description

Chain-shaped cerium oxide-based hollow fine particles, a method for producing the same, a coating liquid for forming a transparent film containing the fine particles, and a substrate with a transparent film

The present invention relates to a chain-shaped cerium oxide-based hollow fine particle having a cavity that penetrates the inside, a method for producing the chain-shaped cerium oxide-based hollow fine particle, and a coating liquid for forming a transparent film containing the chain-shaped cerium oxide-based hollow fine particle, and A substrate with a transparent film containing a transparent film of chain-like cerium oxide-based hollow fine particles is formed on the surface of the substrate.

In the past, hollow cerium oxide particles having a particle diameter of about 0.1 to 300 μm are known (see Patent Document 1, Patent Document 2, and the like). Further, by precipitating active cerium oxide from an aqueous solution of an alkali metal citrate on a core made of a material other than cerium oxide, the material is removed without destroying the cerium oxide shell to produce a dense cerium oxide shell. The method of hollow particles is well known (refer to Patent Document 3, etc.).

In addition, a micron-sized spherical cerium oxide particle having a core-shell structure having a sloping structure in which the outer peripheral portion is a shell and the center portion is hollow, and the shell is dense and has a thicker inner side is known (refer to Patent Document 4, etc.). .

In addition, the applicant of the present invention has previously proposed to completely cover the surface of the porous inorganic oxide fine particles by ruthenium oxide or the like to obtain nano-sized composite oxide fine particles having a low refractive index (refer to Patent Document 5), and A cerium oxide coating layer is formed on the core particles of the composite oxide made of an inorganic oxide other than cerium oxide and cerium oxide, and then an inorganic oxide other than cerium oxide is removed, and if cerium oxide is coated as needed, a void is formed inside. A low-refractive-index nanometer-sized cerium oxide-based fine particle (see Patent Document 6).

On the other hand, the present applicant has previously proposed to form chain-shaped cerium oxide particles by hydrothermal treatment of cerium oxide particles under weakly acidic conditions (see Patent Document 7). In the non-hollow particles, since the refractive index of the particles is not 1.45 or less, in order to obtain particles having a low refractive index, the applicant further proposes to form a chain-like hollow by adding an electrolyte substance in the formation stage of the hollow cerium oxide particles. Cerium oxide particles (see Patent Documents 8 and 9).

However, in the cerium oxide-based hollow particles related to the proposal of the applicant of the present invention, depending on the purpose and use of the particles, a sufficient low refractive index effect may not be obtained. In other words, even if the inside of each particle is hollowed out, the void volume is limited from the viewpoint of particle strength, and there is a limit even if the refractive index is lowered. Therefore, cerium oxide-based hollow fine particles having a different particle structure from the conventional one are required.

Prior technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei 6-330606

Patent Document 2: Japanese Patent Publication No. 7-013137

Patent Document 3: Special Table 2000-500113

Patent Document 4: Japanese Patent Publication No. 11-029318

Patent Document 5: Japanese Patent Publication No. 07-133105

Patent Document 6: JP-A-2001-233611

Patent Document 7: JP-A-2004-055298

Patent Document 8: Special Table 2004-099074

Patent Document 9: JP-A-2005-186435

The present invention has been developed based on the invention described in the above-mentioned Patent Document 6, and it is intended to obtain a porous oxidized cerium-based fine particle having a low refractive index and a porous material made of an inorganic oxide other than cerium oxide and cerium oxide. The composite oxide particles (primary particles) are chain-like, and the surface of the chain-like particles is coated with cerium oxide, and then the inorganic oxide other than cerium oxide is removed to produce a chain-shaped yttrium oxide hollow having a cavity penetrating the inside of the outer shell. The method of microparticles.

In addition, it is an object of the present invention to provide a coating material for film formation which is excellent in stability, film formability, and the like, and contains the matrix-forming hollow granules and the matrix-forming substrate.

Further, an object of the present invention is to provide a film comprising the above-mentioned chain-like cerium oxide-based hollow fine particles on a surface of a substrate, and having a low refractive index and adhesion to a substrate, strength, scratch resistance, and anti-reflection ability. And an excellent film-attached substrate such as anti-glare property.

The chain-shaped yttria-based hollow fine particles of the present invention are characterized in that the yttrium oxide-based hollow fine particles (primary particles) having a shell on the outside and having voids therein are connected in a chain shape, and have through-holes through which voids are interpenetrated, and the average length (L) 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.

Preferably, the thickness (T _s ) of the outer casing is in the range of 2 to 100 nm, and the ratio (Ts) / (W) to the average width (W) is in the range of 0.05 to 0.30.

The ratio (D _s )/(W) of the ratio of the average diameter (D _s ) of the through holes to the average width (W) is preferably in the range of 0.1 to 0.9.

Preferably, it is composed of an inorganic oxide other than cerium oxide and cerium oxide, and when MO _x represents an inorganic oxide other than cerium oxide, the molar ratio MO _x /SiO _{2 is} in the range of 0.0001 to 0.2.

The method for producing a chain yttria-based hollow fine particle of the present invention is characterized by the following steps (a) to (f).

(a) simultaneously adding an aqueous solution of a citrate and/or an acidic citric acid solution and an aqueous solution of an alkali-soluble inorganic compound to an aqueous alkali solution, or simultaneously adding a seed particle having a solid concentration of 0.01 to 2% by weight. In the dispersed aqueous alkali solution, a composite oxide having a molar ratio MO _x /SiO ₂ (A) in the range of 0.1 to 2 when cerium oxide is represented by SiO ₂ and inorganic oxide other than cerium oxide is represented by MO _x a step of primary particle dispersion;

(b) a step of washing the aforementioned primary particle dispersion;

(c) a step of preparing a chain-like composite oxide particle dispersion by subjecting the washed primary particle dispersion to hydrothermal treatment at 50 to 300 ° C in the presence of an electrolyte;

(d) forming a cerium oxide or cerium oxide ‧ alumina coating layer, and preparing a cerium oxide or cerium oxide ‧ alumina coating chain-like composite oxide particle dispersion;

(e) adding an acid to the dispersion of cerium oxide or cerium oxide ‧ alumina-coated chain-like composite oxide particles, and removing at least a part of elements other than ruthenium constituting the composite oxide particles to form chain cerium oxide-based hollow fine particles The step of dispersing the liquid;

(f) a step of washing the resulting dispersion.

The electrolyte in the aforementioned step (c) is preferably an alkaline earth metal salt.

After the aforementioned step (f), it is preferred to carry out the following step (g).

(g) A step of hydrothermal treatment of a chain-shaped cerium oxide-based hollow fine particle dispersion liquid in the range of 50 to 300 °C.

The above step (d) is preferably any one of the following steps (d-1), the following step (d-2), and the following step (d-3).

(d-1) In the chain-like composite oxide particle dispersion obtained in the above step (c), an aqueous alkali solution and an organic hydrazine compound represented by the following chemical formula (1) and/or a partially hydrolyzed product thereof are added in a chain form. Step of forming a cerium oxide coating layer on the composite oxide particles

R _n SiX _(4-n) ‧‧‧(1)

[R, R: an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an alkylene group, an epoxy group, a methacryl group, an amine group, a CF ₂ group; X: an alkoxy group having 1 to 4 carbon atoms; a stanol group, a halogen or a hydrogen; n: an integer of 0 to 3];

(d-2) a step of adding an alkali aqueous solution and an acidic citric acid solution to form a cerium oxide coating layer on the chain-like composite oxide particles in the chain-like composite oxide particle dispersion obtained in the above step (c);

(d-3) A step of forming a cerium oxide coating layer on the chain-like composite oxide particles by adding an aqueous citric acid solution and an aqueous solution of alumina in the chain-like composite oxide particle dispersion obtained in the above step (c).

The coating liquid for forming a transparent film of the present invention is characterized in that it contains the chain-like cerium oxide-based hollow fine particles and a matrix-forming component.

The transparent film-attached substrate of the present invention is characterized in that the transparent film formed by the coating liquid for forming a transparent film is formed on the surface of the substrate alone or together with another film.

According to the present invention, novel chain yttria-based hollow fine particles having voids penetrating the inside of the outer casing can be provided. The novel chain-like yttrium oxide-based hollow microparticles have a lower refractive index than the cerium oxide-based hollow microparticles in which the hollow microparticles are linked in a chain.

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

In addition, it is possible to provide a coating material for film formation which is excellent in stability, film formability, and the like, and the matrix-forming component for forming a matrix of the oxidized cerium oxide-based hollow fine particles.

In addition, it is possible to provide a film having the above-mentioned chain-like cerium oxide-based hollow fine particles on the surface of the substrate, and having excellent refractive index, adhesion to the substrate, strength, scratch resistance, and antireflection ability. The substrate of the film.

Form of implementing the invention [chain oxidized cerium hollow microparticles]

First, the chain cerium oxide-based hollow fine particles of the present invention will be described.

The chain-shaped yttria-based hollow fine particles of the present invention are characterized in that the yttrium oxide-based hollow fine particles (primary particles) having a shell on the outside and having voids therein are connected in a chain shape, and have through-holes through which voids are interpenetrated, and the average length (L) 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.

Cerium oxide hollow microparticles (primary particles)

The chain-shaped cerium oxide-based hollow fine particle system has a shell on the outside and a hollow cerium-based hollow fine particle (primary particle) inside, which is connected in a chain shape.

Fig. 1 is a model diagram showing a cross section of the chain-like cerium oxide-based hollow fine particles of the present invention.

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

When the size of the primary particles is less than 10 nm, it tends to be difficult to form a chain and to agglomerate, and it is difficult to obtain a chain-like yttrium oxide-based hollow fine particle having a desired low refractive index.

When the size of the primary particles exceeds 300 nm, the particles are too large, and the chain formation is difficult, and it is difficult to obtain the desired chain-like cerium oxide-based hollow fine particles.

The average width (W) of the chain-shaped cerium oxide-based hollow fine particles is as large as or equal to the primary particle diameter as shown in Fig. 1, and is in the range of 10 to 300 nm, and more preferably in the range of 15 to 200 nm. good.

The linear cerium oxide-based hollow fine particle-based primary particles are connected in a chain shape, but the average length (L) is preferably from 20 to 1,500 nm, more preferably from 40 to 1,000 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 two, and it is impossible to form a chain-like yttrium oxide-based hollow fine particle having a desired low refractive index, and if the average length (L) exceeds 1500 nm, Then, it is agglomerated or entangled with each other, and it is difficult to obtain the desired chain-like cerium oxide-based hollow fine particles.

Although the thickness (T _s ) of the outer casing differs depending on the primary particle diameter or the average width (W), it is preferably from 2 to 100 nm, more preferably from 3 to 50 nm.

When the thickness (T _s ) of the outer casing is less than 2 nm, when at least a part of the elements other than the latter are removed, the hollow structure may not be maintained, and it may be difficult to obtain the desired chain-shaped cerium oxide-based hollow fine particles.

When the thickness (T _s ) of the outer shell exceeds 100 nm, the internal voids are small, and it is difficult to obtain the chain-like yttrium oxide-based hollow fine particles having a desired low refractive index.

Further, the ratio (T _s )/(W) of the thickness (T _s ) of the outer casing to the average width (W) is preferably 0.05 to 0.30, more preferably 0.05 to 0.2.

When (T _s )/(W) is less than 0.05, when at least a part of elements other than ruthenium is removed, the hollow structure may not be maintained, and it may be difficult to obtain chain yttrium oxide-based hollow fine particles.

When (T _s )/(W) exceeds 0.30, the internal voids are small, and it is difficult to obtain the chain-like yttrium oxide-based hollow fine particles having a desired low refractive index.

The ratio (D _s )/(W) of the ratio of the average diameter (D _s ) of the through holes to the average width (W) is preferably 0.1 to 0.9, more preferably 0.3 to 0.8.

When (D _s )/(W) is less than 0.1, the voids in the through-holes are small, and the contribution to the low refractive index is small, and it is difficult to obtain the chain-like yttrium oxide-based hollow fine particles having a desired low refractive index.

It is difficult to obtain a chain-like cerium oxide-based hollow fine particle system in which (D _s )/(W) exceeds 0.9.

Such a chain-like cerium oxide-based hollow fine particle system has a refractive index of 1.10 to 1.35, more preferably in the range of 1.10 to 1.30.

It is difficult to obtain a chain yttria-based hollow fine particle having a refractive index of less than 1.10, and a refractive index of more than 1.35 is excellent in adhesion to a substrate, strength, and scratch resistance, but the antireflection ability is insufficient.

Linear silicon oxide-based hollow fine lines of the invention is composed of an inorganic oxide other than silicon oxide and silicon oxide, at molar ratio of MO MO when _X represents an inorganic oxide other than silicon oxide _x / SiO ₂ is preferably from 0.0001 ～0.2 range.

It is difficult to obtain a chain cerium oxide-based hollow fine particle system having a molar ratio of MO _x /SiO _{2 of} less than 0.0001, and a molar ratio of MO _x /SiO ₂ exceeding 0.2 is described later, but inorganic oxide other than cerium oxide is used. There are few removals, and there are cases where chain-like yttrium oxide-based hollow fine particles having a low refractive index are not obtained.

In the chain cerium oxide-based hollow fine particles of the present invention, examples of the inorganic oxide other than cerium oxide include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , and P. 1 or 2 or more of ₂ O ₅ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , and WO ₃ . Examples of the two or more kinds of inorganic oxides include TiO ₂ -Al ₂ O ₃ and TiO ₂ -ZrO ₂ . Among them, Al ₂ O _{3 is} preferred.

Further, the average length (L) and the average width (W) of the chain yttria-based hollow fine particles of the present invention are transmission electron micrographs (TEM) of the chain-shaped yttria-based hollow fine particles, which are measured by a vernier caliper. The length and width of 100 particles, the average of which.

Further, the average thickness (T _s ) of the outer casing and the average diameter (D _s ) of the through holes can be measured by observing a transmission electron micrograph (TEM) of the cross section of the particles.

Furthermore, the refractive index is obtained by the following procedure.

(1) A chain-shaped cerium oxide-based hollow fine particle dispersion liquid is collected in an evaporator to evaporate the dispersion medium.

(2) This was dried at 120 ° C to become a powder.

(3) The standard refractive index droplets 2, 3 having a known refractive index are dropped onto a glass plate, and the above powder is mixed therein.

(4) The operation of the above (3) is carried out using various standard refractive index liquids, and the refractive index of the standard refractive index liquid when the mixed liquid is made transparent is regarded as the refractive index of the chain-shaped cerium oxide-based hollow fine particles.

[Method for Producing Cerium Oxide Microparticles]

Next, a method for producing the chain-like cerium oxide-based hollow fine particles of the present invention will be described.

The method for producing a chain-like cerium oxide-based hollow fine particle of the present invention is characterized by the following steps (a) to (f).

(a) simultaneously adding an aqueous solution of a citrate and/or an acidic citric acid solution and an aqueous solution of an alkali-soluble inorganic compound to an aqueous alkali solution, or simultaneously adding a seed particle having a solid concentration of 0.01 to 2% by weight. In the dispersed aqueous alkali solution, a composite oxide having a molar ratio MO _x /SiO ₂ (A) in the range of 0.1 to 2 when cerium oxide is represented by SiO ₂ and inorganic oxide other than cerium oxide is represented by MO _x a step of primary particle dispersion;

(b) a step of washing the aforementioned primary particle dispersion;

(c) a step of preparing a chain-like composite oxide particle dispersion by subjecting the washed primary particle dispersion to hydrothermal treatment at 50 to 300 ° C in the presence of an electrolyte;

(d) forming a cerium oxide or cerium oxide ‧ alumina coating layer, and preparing a cerium oxide or cerium oxide ‧ alumina coating chain-like composite oxide particle dispersion;

(e) adding an acid to the dispersion of cerium oxide or cerium oxide ‧ alumina-coated chain-like composite oxide particles, and removing at least a part of elements other than ruthenium constituting the composite oxide particles to form chain cerium oxide-based hollow fine particles The step of dispersing the liquid;

(f) a step of washing the resulting dispersion.

Step (a)

As the citrate, one or two or more kinds of citrates selected from alkali metal silicates, ammonium citrates and organic acid silicates are preferably used. The alkali metal citrate may, for example, be sodium citrate (water glass) or potassium citrate. Examples of the organic base include a quaternary ammonium salt such as a tetraethylammonium salt, monoethanolamine, diethanolamine or triethanolamine. The amine is also contained in an ammonium citrate or an organic base citrate, and also contains an alkaline solution in which a quaternary ammonium hydroxide, an amine compound or the like is added to the citric acid solution.

As the acidic citric acid solution, a citric acid solution obtained by removing a base by a cation exchange resin treatment or an aqueous citric acid solution can be used, and particularly preferably an acidic citric acid having a concentration of about 2 wt% or less and a concentration of SiO _{2 of} about 7% by weight or less. liquid.

Examples of the inorganic oxide include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , and WO _{3 .} One or two or more types. Examples of the two or more kinds of inorganic oxides include TiO ₂ -Al ₂ O ₃ and TiO ₂ -ZrO ₂ .

Among them, Al ₂ O _{3 is} preferred because spherical primary particles are easily obtained and are easily removed.

As a raw material of such an inorganic oxide, an alkali-soluble inorganic compound is preferably used, and examples thereof include an alkali metal salt or an alkaline earth metal salt or an ammonium salt of a metal or a non-metal oxyacid which constitutes an inorganic oxide. A grade 4 ammonium salt, more specifically, sodium aluminate, sodium tetraborate, ammonium zirconium carbonate, potassium citrate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, sodium phosphate or the like is suitable.

In order to prepare a composite oxide primary particle dispersion, an aqueous alkali solution of the inorganic compound may be prepared in advance, or a mixed aqueous solution may be prepared, and the aqueous solution may be used in an aqueous solution according to a composite ratio of a target cerium oxide to an inorganic oxide other than cerium oxide. Among them, it is preferably added in an aqueous alkali solution having a pH of 10 or more while stirring.

The ratio of addition of the cerium oxide raw material to the inorganic compound raw material added to the aqueous alkali solution is represented by SiO _{2 as} a cerium oxide component, and when MO _x represents an inorganic compound other than cerium oxide, the molar ratio MO _x /SiO ₂ is 0.01 to 2, In particular, it is preferably in the range of 0.1 to 1. When MO _x /SiO _{2 is} less than 0.01, the void volume of the chain cerium oxide-based hollow fine particles finally obtained is not sufficiently large. On the other hand, when MO _x /SiO ₂ exceeds 2, a spherical composite oxide is obtained. When the primary particle system is difficult, even if the spherical composite oxide fine particles are destroyed when the elements other than the crucible are removed, the chain-like cerium oxide-based hollow fine particles having voids inside can not be obtained.

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 is mainly a structure in which elements other than cerium and lanthanum are alternately bonded via oxygen. In other words, a structure in which an oxygen atom is bonded to four bonding hands of a ruthenium atom, and an element other than ruthenium oxide is bonded to the oxygen atom is formed in the step (e) to be described later. The shape of the composite oxide primary particles linked in a chain shape is not destroyed, and the element M can be removed.

The composite oxide primary particles have an average particle diameter of 5 to 280 nm, more preferably 10 to 200 nm.

When the average particle diameter of the primary particles of the composite oxide is less than 5 nm, the ratio of the outer shell of the chain-shaped cerium oxide-based hollow fine particles is increased, and the ratio of the void volume is not sufficiently large, and the average particle size of the composite oxide primary particles is large. When the diameter exceeds 280 nm, the chain formation in the step (b) is difficult, and the removal of elements other than the ruthenium in the step (d) is insufficient, and the void volume of the chain yttria-based hollow fine particles is not sufficiently large, resulting in low refraction. The rate of particles can become difficult.

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

As the seed particles, an inorganic oxide such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ or CeO ₂ or a composite oxide such as SiO ₂ -Al ₂ O ₃ or TiO ₂ -Al is used. _As the fine particles of ₂ O ₃ , TiO ₂ -ZrO ₂ , SiO ₂ -TiO ₂ , SiO ₂ -TiO ₂ -Al ₂ O ₃ or the like, it is usually preferred to use such a sol. Such a dispersion of seed particles can be prepared by a conventional method. For example, hydrolysis can be carried out by adding an acid or a base to a metal salt or a mixture of metal salts corresponding to the above inorganic oxide or a metal alkoxide, and if necessary, it can be obtained by aging.

In the seed particle-dispersed aqueous alkali solution, it is preferred to add an aqueous solution of the above compound to the aqueous solution of the seed particles in which the adjusted sub-pH 10 or more is added, in the same manner as in the method of adding the aqueous alkali solution. As described above, when the composite oxide fine particles are grown by using the seed particles as seeds, the particle size control of the grown particles is easy, and the particle size can be obtained. The addition ratio of the cerium oxide raw material and the inorganic oxide added to the seed particle dispersion is the same as that in the case of adding the aqueous alkali solution.

The above cerium oxide raw material and inorganic oxide raw material have high solubility on the alkali side. However, when the two are mixed in the pH range in which the solubility is high, the solubility of the oxo acid ions such as citric acid ions and aluminate ions is lowered, and the composites are precipitated to grow into colloidal particles or precipitated on the seed particles. And cause the particles to grow.

In the present invention, an aqueous solution of citrate and/or an aqueous solution of an acidic citric acid and an alkali-soluble inorganic compound are added until the average particle diameter (D _p1 ) of the composite oxide primary particles is 5 to 280 nm, and the addition may be Continuous or intermittent, it is preferred to add both at the same time.

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

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

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

The electrolyte salt may, for example, be a water-soluble electrolyte salt such as sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, ammonium nitrate, ammonium sulfate, magnesium chloride or magnesium nitrate.

When an electrolyte salt is used, it is preferably added at a time point of about 1/5 to 4/5 of the average particle diameter of the obtained composite oxide primary particles, and the addition system may be added at this time point in total, or an alkali metal may be added. An inorganic compound other than ceric acid or cerium oxide is continuously or intermittently added while growing particles of the composite oxide fine particles.

Although the addition amount of the electrolyte salt depends on the concentration of the composite oxide primary particle dispersion, when the aforementioned molar ratio (M _Ea ) / (M _Sa ) is less than 0.1, the effect of adding the electrolyte salt is insufficient. When the acid is added to the step (e) to remove at least a part of the elements other than the ruthenium constituting the primary particles of the composite oxide, the composite oxide fine particles cannot be maintained and destroyed, and the chain oxidized yttrium-based hollow fine particles having voids therein are obtained. difficult. Although the reason for the addition of such an electrolyte salt is not clear, it is considered that the cerium oxide on the surface of the composite oxide primary particles grown by the particles is increased, and the acid-insoluble cerium oxide-based protective film of the composite oxide primary particles is used. effect.

Therefore, although a ruthenium oxide or ruthenium oxide ‧ alumina coating layer is formed in the step (d) described later, the formed ruthenium oxide or ruthenium oxide ‧ alumina coating layer may be thinned.

Even if the aforementioned molar ratio (M _Ea )/(M _Sa ) exceeds 10, the effect of adding the aforementioned electrolyte does not increase, and new fine particles are generated, or the economy is lowered.

Step (b)

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

The washing method is not particularly limited as long as the cation, the anion, and the electrolyte can be removed, and a conventional method can be employed. In the present invention, since the particles are fine particles, an ultrafiltration membrane method or an ion exchange resin method is suitably employed. You can also use both.

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 composite oxide primary particle dispersion, and hydrothermal treatment is carried out at 50 to 300 ° C and more at 80 to 250 ° C in the presence of an electrolyte to prepare a chain-like composite oxide particle dispersion.

The electrolyte is not particularly limited as long as the composite oxide primary particles are chained, but in the present invention, an alkaline earth metal salt is preferred.

The alkaline earth metal salt may, for example, be a hydrochloride, a nitrate, a sulfate or an organic acid salt such as magnesium or calcium.

The concentration of the composite oxide primary particle dispersion at the time of adding the electrolyte is preferably 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, based on the solid content.

When the concentration of the composite oxide primary particle dispersion is less than 0.1% by weight in terms of solid content, although chaining can be performed, productivity is low, and if the concentration of the composite oxide primary particle dispersion exceeds 20 in terms of solid content At % by weight, the particles become aggregates.

Further, the addition amount of the electrolyte, to the dispersion-based composite oxide particles by weight of a (W _P1) and the weight of the electrolyte (W _EL) The ratio of _{(W EL) / (W P1} ) is 0.001 to 0.8, more in It is preferably in the range of 0.01 to 0.2.

When (W _EL )/(W _P1 ) is less than 0.001, the composite oxide primary particles are not chained, and if (W _EL )/(W _P1 ) exceeds 0.8, the primary particles of the composite oxide become Condensed body.

In the present invention, an acidic citric acid solution may be added in addition to the electrolyte. The acidic citric acid liquid is the same acidic citric acid liquid as the acidic citric acid liquid used in the step (d-2) described later, and the acidic citric acid liquid is added in the weight of the composite oxide primary particles in the dispersion (W _P1 ) The ratio (W _S )/(W _P1 ) to the weight (W _S ) of the SiO ₂ of the acidic citric acid solution is preferably 0.01 to 1, more preferably 0.02 to 0.5.

When (W _S )/(W _P1 ) is less than 0.01, although it depends on the particle diameter of the composite oxide primary particles, it promotes chaining or fails to maintain the chained composite oxide primary particles. In the chain shape, if (W _S )/(W _P1 ) exceeds 1, the removal of elements other than ruthenium in step (e) described later becomes difficult, and even if it is removable, voids inside the chain-like particles cannot be formed. Through-holes that pass through.

When the hydrothermal treatment temperature is less than 50 ° C, the chain-forming system does not proceed, and the monodisperse composite oxide primary particles remain in a large amount, and when the hydrothermal treatment temperature exceeds 300 ° C, the aggregated particles tend to increase.

Further, although the hydrothermal treatment time varies depending on the temperature, it is about 1 to 24 hours.

Step (d)

Next, a ruthenium oxide or ruthenium oxide ‧ alumina coating layer is formed.

In order to form a ruthenium oxide or ruthenium oxide ‧ alumina coating layer, there are three methods. The first method is the step (d-1), in which the alkali aqueous solution and the organic hydrazine compound represented by the following chemical formula (1) are added to the chain-like composite oxide particle dispersion obtained in the above step (c) and/or Partially hydrolyzed method.

R _n SiX _(4-n) ‧‧‧(1)

[R, R: an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an alkylene group, an epoxy group, a methacryl group, an amine group, a CF ₂ group; X: an alkoxy group having 1 to 4 carbon atoms; a stanol group, a halogen or a hydrogen; n: an integer of 0 to 3].

Specific examples of the organic ruthenium compound include tetramethoxy decane, tetraethoxy decane, tetraisopropoxy decane, methyl trimethoxy decane, dimethyl dimethoxy decane, and phenyl trimethoxy. Base decane, diphenyl dimethoxy decane, methyl triethoxy decane, dimethyl diethoxy decane, phenyl triethoxy decane, diphenyl diethoxy decane, isobutyl trimethyl Oxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, vinyltris(β-methoxyethoxy)decane, 3,3,3-trifluoropropyltrimethoxydecane, A 3-,3,3-trifluoropropyldimethoxydecane, β-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, γ-glycidoxytripropyltrimethoxy Baseline, γ-glycidoxypropylmethyldiethoxydecane, γ-glycidoxypropyltriethoxydecane, γ-methylpropenyloxypropylmethyldimethoxy Baseline, γ-methacryloxypropyltrimethoxydecane, γ-methylpropenyloxypropylmethyldiethoxydecane, γ-methylpropenyloxypropyltriethoxy Decane, N-β (aminoethyl) γ-amine C Methyldimethoxydecane, N-β (aminoethyl) γ-aminopropyltrimethoxydecane, N-β (aminoethyl) γ-aminopropyltriethoxydecane, γ-aminopropyl Trimethoxydecane, γ-aminopropyltriethoxydecane, N-phenyl-γ-aminopropyltrimethoxydecane, γ-mercaptopropyltrimethoxydecane, trimethylstanol, methyl three Chlorodecane, methyldichlorodecane, dimethyldichlorodecane, trimethylchlorodecane, phenyltrichlorodecane, diphenyldichlorodecane, vinyltrichlorodecane, trimethylbromodecane, diethyl Decane and so on.

The second method is the step (d-2), which is a method of adding an aqueous alkali solution and an acidic citric acid solution to the chain-like composite oxide particle dispersion obtained in the above step (c).

As the acidic citric acid solution, an aqueous citric acid solution is used, for example, an acidic citric acid solution obtained by dehydrating water glass with an ion exchange resin. The concentration of the acidic citric acid solution is 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 the step (d-3), which is a method of adding an aqueous citric acid solution and an aqueous solution of an aluminate to the chain-like composite oxide particle dispersion obtained in the above step (c).

In the above, the amount of the organic cerium compound or the acidic citric acid liquid used for forming the cerium oxide coating layer is 10 to 2000% by weight, particularly 20 to 1000% by weight, based on the solid content. The scope.

When the amount of the organic cerium compound or the acidic citric acid solution is less than 10% by weight of the chain-like composite oxide particles, the coating layer is thin, and in step (e), when elements other than cerium are removed The chain-like particles collapse and become chain-shaped yttria-based hollow fine particles having open pores on the outside.

When the amount of the organic cerium compound or the acidic citric acid solution exceeds 2000% by weight of the chain-like composite oxide particles, the removal of elements other than cerium is difficult, or the outer shell is too thick, and the desired amount is not obtained. Low refractive index chain yttrium oxide hollow fine particles.

Further, the addition of the aqueous alkali solution is preferably such that the pH of the chain-like composite oxide particle dispersion is maintained at 7 to 13.5, particularly preferably at 10 to 13. When the pH of the chain-like composite oxide particle dispersion is less than 7, the chain-like composite oxide particles are aggregated, and the formation of a uniform coating layer and particle growth are not possible.

When the pH of the chain-like composite oxide particle dispersion exceeds 13.5, since the solubility of cerium oxide and aluminum oxide is high, formation of a cerium oxide layer, a cerium oxide layer, an alumina layer, and particle growth become difficult, and it is difficult to obtain The chain of cerium oxide is hollow microparticles.

Further, in the step (d-3), when an aqueous citric acid solution and an aqueous solution of aluminate are added to the formation of the yttrium oxide-alumina coating layer, the molar ratio of Al ₂ O ₃ /SiO ₂ is 0.01 to 0.5, more It is preferably in the range of 0.05 to 0.3.

When the molar ratio of Al ₂ O ₃ /SiO _{2 is} less than 0.01, there is no difference from the formation of the ruthenium oxide layer as described above, and the ease of removal of elements other than ruthenium is lowered due to the formation of the ruthenium oxide ‧ alumina coating layer.

When the molar ratio of Al ₂ O ₃ /SiO ₂ exceeds 0.5, the amount of alumina in the coating layer is too large, and when the element other than cerium is removed in the step (e), the coating layer cannot be maintained, and the coating layer is opened. The hollow chain of yttrium oxide hollow fine particles.

The amount of addition of the aqueous ceric acid solution and the aqueous aluminate solution to the formation of the cerium oxide/alumina coating layer is 10 to 2000% by weight based on the solid content of the cerium oxide and the alumina, and more preferably It is preferably in the range of 20 to 1000% by weight.

When the amount of the aqueous solution of the citric acid and the aqueous solution of the aluminate is less than 10% by weight of the chain-like composite oxide particles, the coating layer is thin, and in the step (e), when the element other than ruthenium is removed, The chain-like particles collapse and become chain-shaped yttria-based hollow fine particles having open pores on the outside.

When the amount of the aqueous solution of the citric acid and the aqueous solution of the aluminate exceeds 2000% by weight of the chain-like composite oxide particles, the removal of elements other than ruthenium is difficult, or the outer shell is too thick to be obtained. Low refractive index chain yttrium oxide hollow fine particles.

When the cerium oxide layer or the cerium oxide layer is formed, the concentration of the chain-like composite oxide particle dispersion is preferably from 0.5 to 20% by weight, more preferably from 1 to 10% by weight, based on the solid content.

When the concentration of the chain-like composite oxide particle dispersion is less than 0.5% by weight in terms of solid content, the productivity is lowered, and when it exceeds 20% by weight, the particles become aggregates.

When the cerium oxide or cerium oxide ‧ alumina coating layer is formed, the temperature is usually from 30 to 150 ° C, more preferably from 50 to 100 ° C.

When a ruthenium oxide or ruthenium oxide/alumina coating layer is formed, when the temperature is less than 30 ° C, it takes a long time to form a coating layer having a desired thickness in order to form a ruthenium oxide/alumina coating layer.

When the cerium oxide or the cerium oxide/alumina coating layer is formed, if the temperature exceeds 150 ° C, the chain-like composite oxide particles aggregate due to the difference in concentration.

Step (e)

An acid is added to the cerium oxide or cerium oxide ‧ alumina-coated composite oxide particle dispersion to remove at least a part of elements other than cerium oxide constituting cerium oxide or cerium oxide ‧ alumina-coated composite oxide particles, thereby forming chain oxidation Tantalum hollow microparticle dispersion.

When removing elements other than cerium, for example, by adding a mineral acid or an organic acid to dissolve and remove, or contacting the cation exchange resin to remove ion exchange, or by combining these methods.

When the element other than cerium is removed, the concentration of cerium oxide or cerium oxide/alumina-coated composite oxide particles in the cerium oxide or cerium oxide-alumina-coated composite oxide particle dispersion is different depending on the treatment temperature. However, it is preferably converted into an oxide in an amount of from 0.1 to 50% by weight, particularly preferably from 0.5 to 25% by weight. When the concentration of the cerium oxide-coated composite oxide particles is less than 0.1% by weight, the production efficiency is low, and if it exceeds 50% by weight, the composite oxide particles having a large content of elements other than cerium may not be uniform or efficient. The ground is removed in a small number of times.

The removal of the above-mentioned elements is preferably carried out until the MO _x /SiO ₂ of the obtained chain yttria-based hollow fine particles is from 0.0001 to 0.2, particularly from 0.0001 to 0.1.

Step (f)

The chain-like cerium oxide-based hollow fine particle dispersion obtained in the step (e) is mainly removed by the cation of an element other than an acid or hydrazine and the dissolved cerium oxide.

The washing method is the same as in the step (b). The degree of washing is preferably such that the cation of the element other than the acid or hydrazine and the dissolved cerium oxide are substantially not formed.

Step (g)

The chain cerium oxide-based hollow fine particle dispersion is hydrothermally treated at 50 to 300 ° C, more preferably at 80 to 250 ° C.

In the present invention, the chain cerium oxide-based hollow fine particles obtained in the step (f) can be used as it is, and it is preferred to carry out the hydrothermal treatment on the above step (f).

When the hydrothermal treatment temperature is less than 50 ° C, the densification of the outer shell of the obtained chain-like cerium oxide-based hollow fine particles becomes insufficient, and depending on the usage of the chain-like cerium oxide-based hollow fine particles, the solvent or the substrate for forming a transparent film is formed. Will enter the cavity, and the effect of low refractive index is not obtained. In addition, the content of impurities such as an alkali metal or ammonia in the chain-like cerium oxide-based hollow fine particles obtained is not effectively reduced, and the stability of the coating liquid for forming a film is insufficient, so that the strength of the obtained film is insufficient.

When the hydrothermal treatment temperature exceeds 300 ° C, it becomes an aggregate of chain cerium oxide-based hollow fine particles.

After the hydrothermal treatment, if necessary, it can be washed in the same manner as in the above step (b).

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

Furthermore, in the method for producing a chain-shaped cerium oxide-based hollow fine particle of the present invention, the obtained chain-like cerium oxide-based hollow fine particle dispersion is replaced with an organic solvent using an ultrafiltration membrane, a rotary evaporator or the like. An organic solvent dispersion sol is obtained.

Further, the obtained chain cerium oxide-based hollow fine particles can be used by treatment with a decane coupling agent or the like by a conventional method.

Further, in the method for producing a chain cerium oxide-based hollow fine particle of the present invention, after washing, drying is carried out, and if necessary, calcination is possible.

[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 film of the present invention contains the chain-like cerium oxide-based hollow fine particles and a matrix-forming component.

Dispersing medium

As the dispersion medium of the coating liquid, a conventional dispersion medium can be used, and specific examples thereof include water and various organic solvents.

The organic solvent to be used in the present invention is not particularly limited as long as it can dissolve or disperse a matrix-forming component to be described later, a polymerization initiator to be used as needed, and uniformly disperse the chain-like cerium oxide-based hollow fine particles. Known dispersion medium.

Specific examples thereof include alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, decyl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexanediol, and isopropyl glycol; Esters of esters, ethyl acetate, butyl acetate, etc.; diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol isopropyl ether, two Ethers such as ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl Ketones such as ketone, cyclohexanone, methylcyclohexanone, dipropyl ketone, methyl amyl ketone, diisobutyl ketone, isophorone, acetoacetone, acetamidine acetate, toluene, Toluene, etc. These may be used alone or in combination of two or more.

Polymerization initiator

In the coating liquid of the present invention, a chain-forming cerium oxide-based hollow fine particle or a matrix-forming component may further contain a polymerization initiator. The polymerization initiator is not particularly limited and may be used. For example, bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide and bis(2,6-dimethoxy) may be mentioned. Benzomethane) 2,4,4-trimethyl-pentylphosphine oxide, 2-hydroxy-methyl-2-methyl-phenyl-propan-1-one, 2,2-dimethoxy Base-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-one, 2-methyl-1-[4-(methylthio)phenyl]-2-? Orolinylpropan-1-one and the like.

Chain oxidized cerium hollow microparticles

As the chain-shaped cerium oxide-based hollow fine particles, the above-mentioned chain-shaped cerium oxide-based hollow fine particles are used.

In the coating liquid of the present invention, inorganic oxide fine particles other than the chain-shaped cerium oxide-based hollow fine particles may be contained as needed.

Examples of the inorganic oxide fine particles include conventional 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 fine particles, and means a component which can form a film on the surface of the substrate, and can be selected from resins suitable for the adhesion to the substrate, hardness, and coatability, and the like, for example, The polyester resin, acrylic resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluororesin, enamel resin, butyral resin, phenol resin, vinyl acetate resin, ultraviolet light used in the past are mentioned. a curing resin, an electron ray-curing resin, an emulsified resin, a water-soluble resin, a hydrophilic resin, a mixture of such resins, a coating resin such as a copolymer or a modified body of the resin, or a alkoxy decane or the like Hydrolyzable organic hydrazine compound, such partial hydrolyzate, and the like.

The total concentration of the matrix-forming component and the chain-like cerium oxide-based hollow fine particles of the coating liquid for forming a transparent film is 1 to 60% by weight, and more preferably 2 to 50% by weight, based on the solid content.

When the solid content concentration of the coating liquid for forming a transparent film is less than 1% by weight, the film thickness required for the primary coating is not obtained. Therefore, if the coating or drying is repeated, the adhesion and the like are insufficient or economical. Sexual disadvantage.

When the solid content concentration exceeds 60% by weight, the film thickness of the obtained transparent film becomes uneven or cracks may occur.

The concentration of the chain cerium oxide-based hollow fine particles in the coating liquid for forming a transparent film is 5 to 80% by weight, particularly 10, based on the solid content of the chain cerium oxide-based hollow fine particles in the obtained transparent film. Use in a range of ~50% by weight.

When the content of the chain cerium oxide-based hollow fine particles in the transparent film is less than 5% by weight based on the solid content, a transparent film having a desired low refractive index is not obtained, and the chain-like yttrium oxide hollow of the present invention can be obtained. Other conventional low refractive index particles are used for the microparticles.

When the content of the chain cerium oxide-based hollow fine particles in the transparent film is more than 80% by weight in terms of the solid content, the transparency, strength, and the like of the film may be insufficient.

In addition, when inorganic oxide fine particles other than the chain-shaped cerium oxide-based hollow fine particles are used as needed, the total concentration of the particles is preferably in the range of the above-mentioned phase.

In addition, the concentration of the matrix-forming component in the coating liquid for forming a transparent film is such that the content of the matrix component in the obtained transparent film is 20 to 95% by weight, particularly 50 to 90% by weight, based on the solid content. use.

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

The concentration of the matrix-forming component in the coating liquid for forming a transparent film is preferably from 0.2 to 57% by weight, particularly preferably from 0.5 to 54% by weight, based on the solid content.

The coating liquid for forming a transparent film is applied onto a substrate and subjected to a known method such as a dipping method, a spray method, a spin coating method, a roll coating method, a bar coating method, a gravure printing method, or a micro gravure printing method. Drying is hardened by a usual method such as ultraviolet irradiation or heat treatment to form a transparent film.

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

[Substrate with transparent film]

Next, a substrate with a transparent film will be described.

In the substrate with a transparent film of the present invention, the transparent film formed by the coating liquid for forming a transparent film is formed on the surface of the substrate alone or together with another film.

Substrate

The base material is a base material such as a plastic sheet such as glass, polycarbonate, acrylic resin, PET, or TAC, a plastic film, a plastic lens, a plastic panel, a cathode wire tube, a fluorescent display tube, or a liquid crystal display panel. The film is formed on the surface of the material, and the film is used alone or on the substrate, and the protective film, the hard coat film, the flattening film, the high refractive index film, the insulating film, the conductive resin film, and the conductivity. The metal fine particle film, the conductive metal oxide fine particle film, and other base film used as needed are formed in combination. Further, when used in combination, the film of the present invention is preferably formed on the outermost surface.

In the transparent coating film, the coating liquid for forming a transparent film can be applied to a substrate by a known method such as a dipping method, a spray method, a spin coating method, or a roll coating method, and further heated or Obtained by ultraviolet irradiation or the like.

The refractive index of the transparent film formed on the surface of the substrate differs depending on the mixing ratio of the chain cerium oxide-based hollow fine particles to the matrix component and the refractive index of the substrate to be used, but is 1.15 to 1.42. Low refractive index. Further, the chain-like cerium oxide-based hollow fine particles of the present invention have a refractive index of 1.10 to 1.35. In this case, the chain-shaped cerium oxide-based hollow fine particles of the present invention have voids inside, and the matrix-forming component such as resin is stopped outside the particles, and the voids inside the chain-shaped cerium oxide-based hollow fine particles are retained.

In the substrate having the transparent film, when the refractive index of the substrate is 1.60 or less, it is recommended to form a film having a refractive index of 1.60 or more (hereinafter also referred to as an intermediate film) on the surface of the substrate. A transparent film containing chain cerium oxide-based hollow fine particles of the present invention. When the refractive index of the intermediate film is 1.60 or more, the difference in refractive index from the transparent film containing the chain yttria-based hollow fine particles of the present invention is large, and a substrate having a transparent film which is more excellent in antireflection performance is obtained. The refractive index of the intermediate film can be adjusted by increasing the refractive index of the metal oxide fine particles used for increasing the refractive index of the intermediate film, the mixing ratio of the metal oxide fine particles and the resin, and the refractive index of the resin to be used.

A mixed liquid of the coating liquid metal oxide particles for forming a film for the intermediate film and the film forming substrate, and an organic solvent is optionally mixed. In the same manner as the film containing the cerium oxide-based fine particles of the present invention, the substrate for forming a film can be obtained by using the same film forming substrate, whereby a substrate having an adhesive film having excellent adhesion between the two films can be obtained.

The invention will be more specifically illustrated by the following examples.

Example 1 Modulation of chain cerium oxide hollow microparticles (P-1)

100 g of cerium oxide. Alumina sol (daily flucene-forming system: USBB-120, average particle size 25 nm, SiO ₂ ‧ Al ₂ O ₃ concentration 20% by weight, solid content Al ₂ O ₃ content 27 weight 3900 g of pure water was added to the solution, and the temperature was maintained at 98 ° C. While maintaining this temperature, 1750 g of an aqueous solution of sodium citrate having a concentration of 1.5% by weight of SiO ₂ and 1750 g of Al ₂ O were added thereto over 6 hours. a concentration of 0.5% by weight of the ₃ aqueous sodium aluminate solution, thereby obtaining SiO ₂ ‧Al ₂ O ₃ primary particles (P-1) dispersion liquid. The molar ratio at this time is MO _x /SiO ₂ =0.2. Further, the pH of the reaction liquid at this time was 12.0. The primary particle average particle diameter of this dispersion was 35 nm. (Step (a))

Next, an ultrafiltration membrane method to wash SiO ₂ ‧Al ₂ O ₃ primary particles (P-1) dispersion liquid, and was concentrated to a solid content concentration of 5 wt% of SiO ₂ ‧Al ₂ O ₃ primary particles (P-1 )Dispersions. (Step (b))

On the other hand, 136 g of an acidic citric acid solution having a concentration of 2 wt% of SiO ₂ and 5.4 g of an aqueous solution of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte for chain formation were prepared and mixed with 300 g of a SiO ₂ ‧Al ₂ O ₃ primary particle (P-1) dispersion having a solid concentration of 5 wt% was mixed, and 9 g of a 2% by weight aqueous NaOH solution was added thereto, followed by hydrothermal treatment at 150 ° C for 3 hours. A dispersion of chain-like composite oxide particles (P-1) having a solid concentration of 5 wt% was prepared. It is then cooled to normal temperature. The pH of the dispersion at this time was 10.9. (Step (c))

Next, 3,900 g of pure water was added to 300 g of a chain-like composite oxide particle (P-1) dispersion having a solid concentration of 5 wt%, and the mixture was heated to 98 ° C, and while maintaining this temperature, 1530 g was added in 17 hours. An aqueous solution of sodium citrate having a concentration of SiO ₂ of 1.5% by weight and 500 g of an aqueous solution of sodium aluminate having a concentration of 0.5% by weight of Al ₂ O ₃ were obtained to obtain cerium oxide-alumina-coated chain-like composite oxide particles (P). -1) Dispersion. (Step (d))

Subsequently, it was washed with an ultrafiltration membrane method and concentrated, and 1,125 g of pure water was added to 500 g of a cerium oxide-alumina-coated chain-like composite oxide particle (P-1) dispersion having a solid concentration of 13% by weight. Then, concentrated hydrochloric acid (concentration: 35.5 wt%) was added dropwise to pH 1.0, and dealumination treatment was carried out. Next, 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added, and the dissolved aluminum salt was separated by an ultrafiltration membrane to obtain a chain-like cerium oxide-based hollow fine particle having a solid concentration of 20% by weight (P). -1) Aqueous dispersion. (Step (e)) (Step (f))

For the obtained chain yttrium oxide hollow fine particles (P-1), the average width, the average length, the thickness of the outer shell, the average diameter of the through holes, the MO _x /SiO ₂ (mole ratio), and the refractive index were measured, in Table 1. Show results. The results are also measured in the same manner as in the examples and comparative examples shown below, 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 method using Series A and AA manufactured by CARGILL as standard refractive liquids. The MO _x was measured by an ICP emission spectroscopic analyzer (Shimadzu Corporation: ICPS-8100), and the SiO ₂ was a value obtained by removing the weight of MO _x and Na ₂ O from the weight of the residual solid component when calcined at 1000 °C.

Manufacture of substrate (A-1) with transparent film

The aqueous dispersion of the chain cerium oxide-based hollow fine particles (P-1) having a solid content concentration of 20% by weight obtained as described above was subjected to a chain oxidation of a solid concentration of 20% by weight using an ultrafiltration membrane and replacing the solvent with ethanol. An alcohol dispersion of lanthanide hollow microparticles (P-1).

An alcohol dispersion in which 50 g of chain cerium oxide-based hollow fine particles (P-1) was sufficiently mixed was diluted with ethanol to a dispersion having a solid concentration of 5 wt%, and 3 g of an acrylic resin (Hitaroid 1007, manufactured by Hitachi Chemical Co., Ltd.) and A mixed solvent of 47 g of isopropyl alcohol and n-butanol in a ratio of 1/1 (by weight) was prepared to prepare a coating liquid.

This coating liquid was applied onto a PET film by a bar coating method, and dried at 80 ° C for 1 minute to obtain a transparent film-attached substrate (A-1) having a transparent film thickness of 100 nm. Table 2 shows the total light transmittance, the haze, the reflectance of light having a wavelength of 550 nm, the refractive index of the film, the adhesion, the scratch resistance, and the pencil hardness of the substrate (A-1) having the transparent film. The results are also measured in the same manner as in the examples and comparative examples shown below, and the results are shown in Table 2.

The total light transmittance and the haze were measured by a haze meter (manufactured by SUGA Tester Co., Ltd.), and the reflectance was measured by a spectrophotometer (Ubest-55, JASCO Corporation). Further, the refractive index of the film was measured by an ellipsometer (EMS-1, manufactured by ULVAC Co., Ltd.). Further, the uncoated PET film had a total light transmittance of 90.7%, a haze of 2.0%, and a reflectance of 7.0% of light having a wavelength of 550 nm.

The pencil hardness was measured by a pencil hardness tester in accordance with JIS K 5400. That is, the pencil was attached to the surface of the film at an angle of 45 degrees, and the specified load was loaded, and pulled at a constant speed to observe the presence or absence of a flaw.

Further, on the surface of the base material (A-1) with the transparent film, 11 parallel flaws were formed at intervals of 1 mm in the longitudinal and lateral directions to make 100 squares, and then the cellophane tape was adhered thereto, followed by the following The number of squares in which the film was not peeled off when the celluloid tape was peeled off was classified into three grades, and the adhesion was evaluated.

More than 90 remaining squares: ◎

Residual squares 85 to 89: ○

The number of remaining squares is 84 or less: △

The scratch resistance was measured by using #0000 steel wool and sliding 50 times at a load of 500 g/cm ² , and the surface of the film was visually observed and evaluated by the following criteria.

Did not see the rib scars: ◎

Slightly see the rib scars: ○

See most of the rib scars: △

The whole face was cut off: ×

Example 2 Modulation of chain cerium oxide hollow microparticles (P-2)

In the same manner as in Example 1, except that 2.7 g of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte was mixed, a chain cerium oxide-based hollow fine particle (P-2) having a solid concentration of 20% by weight was obtained in the same manner. Water dispersion.

Manufacture of substrate (A-2) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-2) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate (A-2) of the film.

Example 3 Modulation of chain cerium oxide hollow microparticles (P-3)

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 as an electrolyte was mixed, a chain cerium oxide-based hollow fine particle (P-3) having a solid concentration of 20% by weight was obtained in the same manner. Water dispersion.

Manufacture of substrate (A-3) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-3) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate (P-3) of the film.

Example 4 Modulation of chain cerium oxide hollow microparticles (P-4)

In the same manner as in Example 1, except that 4.9 g of a Mg(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte was mixed, a chain cerium oxide-based hollow fine particle (P-4) having a solid concentration of 20% by weight was obtained in the same manner. Water dispersion.

Manufacture of substrate (A-4) with transparent film

In the first embodiment, a coating liquid and a transparent film having a film thickness of 100 nm were obtained in the same manner except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-4) having a solid concentration of 20% by weight was used. The substrate (A-4) of the film.

Example 5 Modulation of chain cerium oxide hollow microparticles (P-5)

100 g of cerium oxide ‧ alumina sol (made by Nissan Catalyst): USBB-120, average particle size 25 nm, SiO ₂ ‧ Al ₂ O ₃ concentration 20% by weight, solid content Al ₂ O ₃ content 27 weight 3900 g of pure water was added to the solution, and the temperature was maintained at 98 ° C. While maintaining this temperature, 405 g of an aqueous solution of sodium citrate having a concentration of 1.5% by weight of SiO ₂ and 405 g of TiO _{2 were added} as an Al ₂ O in 6 hours. a concentration of 0.5% by weight of the ₃ aqueous sodium aluminate solution, thereby obtaining SiO ₂ ‧Al ₂ O ₃ primary particles (P-5) dispersion liquid. The molar ratio at this time is MO _x /SiO ₂ =0.2. Further, the pH of the reaction liquid at this time was 12.0. The primary particle average particle diameter of this dispersion was 28 nm. (Step (a))

Next, an ultrafiltration membrane method to wash SiO ₂ ‧Al ₂ O ₃ primary particles (P-5) dispersion liquid was concentrated to a solid content of 5% by weight of SiO ₂ ‧Al ₂ O ₃ primary particles (P-5 )Dispersions. (Step (b))

On the other hand, 136 g of an acidic citric acid solution having a concentration of 2 wt% of SiO ₂ and 5.4 g of an aqueous solution of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte for chain formation were prepared and mixed with 300 g of a SiO ₂ ‧ Al ₂ O ₃ primary particle (P-5) dispersion having a solid concentration of 5 wt% was mixed, and 9 g of a 2% by weight aqueous NaOH solution was added thereto, followed by hydrothermal treatment at 150 ° C for 3 hours. A dispersion of chain-like composite oxide particles (P-5) having a solid concentration of 5 wt% was prepared. It is then cooled to normal temperature. The pH of the dispersion at this time was 10.9. (Step (c))

Next, 3,900 g of pure water was added to 300 g of a chain-like composite oxide particle (P-5) dispersion having a solid concentration of 5 wt%, and the mixture was heated to 98 ° C, and while maintaining this temperature, 1530 g was added in 17 hours. An aqueous solution of sodium citrate having a concentration of SiO ₂ of 1.5% by weight and 500 g of an aqueous solution of sodium aluminate having a concentration of 0.5% by weight of Al ₂ O ₃ were obtained to obtain cerium oxide-alumina-coated chain-like composite oxide particles (P). -5) Dispersion. (Step (d))

Subsequently, it was washed with an ultrafiltration membrane method and concentrated, and 1,125 g of pure water was added to 500 g of a cerium oxide-alumina-coated chain-like composite oxide particle (P-5) dispersion having a solid concentration of 13% by weight. Then, concentrated hydrochloric acid (concentration: 35.5 wt%) was added dropwise to pH 1.0, and dealumination treatment was carried out. Next, 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added, and the dissolved aluminum salt was separated by an ultrafiltration membrane to obtain a chain-like cerium oxide-based hollow fine particle having a solid concentration of 20% by weight (P). -5) Aqueous dispersion. (Step (e)) (Step (f))

Manufacture of substrate (A-5) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-5) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate (A-5) of the film.

Example 6 Modulation of chain cerium oxide hollow microparticles (P-6)

100 g of cerium oxide ‧ alumina sol (made by Nissan Catalyst): USBB-120, average particle size 25 nm, SiO ₂ ‧ Al ₂ O ₃ concentration 20% by weight, solid content Al ₂ O ₃ content 27 weight 3900 g of pure water was added to the solution, and the temperature was maintained at 98 ° C. While maintaining this temperature, 20,900 g of an aqueous solution of sodium citrate having a concentration of 1.5 wt% of SiO ₂ and 20,900 g of Al ₂ O were added as 6 hours. a concentration of 0.5% by weight of the ₃ aqueous sodium aluminate solution, thereby obtaining SiO ₂ ‧Al ₂ O ₃ primary particles (P-6) dispersion liquid. The molar ratio at this time was MOx/SiO ₂ = 0.2. Further, the pH of the reaction liquid at this time was 12.0. The primary particle average particle diameter of this dispersion was 70 nm. (Step (a))

Next, an ultrafiltration membrane method to wash SiO ₂ O ₃ primary particles _{2 ‧Al} (P-6) dispersion liquid was concentrated to a solid content of 5% by weight of SiO ₂ ‧Al ₂ O ₃ primary particles (P-6 )Dispersions. (Step (b))

On the other hand, 136 g of an acidic citric acid solution having a concentration of 2 wt% of SiO ₂ and 5.4 g of an aqueous solution of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte for chain formation were prepared and mixed with 300 g of a SiO ₂ ‧Al ₂ O ₃ primary particle (P-6) dispersion having a solid concentration of 5 wt% was mixed, and 9 g of a 2% by weight aqueous NaOH solution was added thereto, followed by hydrothermal treatment at 150 ° C for 3 hours. A dispersion of chain-like composite oxide particles (P-6) having a solid concentration of 5 wt% was prepared. It is then cooled to normal temperature. The pH of the dispersion at this time was 10.9. (Step (c))

Next, 3,900 g of pure water was added to 300 g of a chain-like composite oxide particle (P-6) dispersion having a solid concentration of 5 wt%, and the mixture was heated to 98 ° C, and while maintaining the temperature, 2,000 g was added for 17 hours. An aqueous solution of sodium citrate having a concentration of SiO ₂ of 1.5% by weight and 700 g of an aqueous solution of sodium aluminate having a concentration of 0.5% by weight of Al ₂ O ₃ were obtained to obtain cerium oxide-alumina-coated chain-like composite oxide particles (P). -6) Dispersion. (Step (d))

Subsequently, it was washed with an ultrafiltration membrane method and concentrated, and 1,125 g of pure water was added to 500 g of a cerium oxide-alumina-coated chain-like composite oxide particle (P-6) dispersion having a solid concentration of 13% by weight. Then, concentrated hydrochloric acid (concentration: 35.5 wt%) was added dropwise to pH 1.0, and dealumination treatment was carried out. Next, 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added, and the dissolved aluminum salt was separated by an ultrafiltration membrane to obtain a chain cerium oxide-based hollow fine particle having a solid concentration of 20% by weight (P). -6) Aqueous dispersion. (Step (e)) (Step (f))

Manufacture of substrate (A-6) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-6) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate (A-6) of the film.

Example 7 Manufacture of substrate (A-7) with transparent film

In Example 1, except that 36.6 g of an alcohol dispersion of chain-like cerium oxide-based hollow fine particles (P-1) was diluted with ethanol to a dispersion having a solid concentration of 5% by weight, and 3.7 g of an acrylic resin (Hitaroid 1007, Hitachi Chemical Co., Ltd.) In the same manner as the mixed solvent of a 1/1 (by weight) mixture of isopropyl alcohol and n-butanol, a substrate having a transparent coating film having a thickness of 100 nm of a coating liquid and a transparent film was obtained in the same manner (A). -7).

Example 8 Manufacture of substrate (A-8) with transparent film

In Example 1, except that 55 g of an alcohol dispersion of chain-like cerium oxide-based hollow fine particles (P-1) was diluted with ethanol to a dispersion having a solid concentration of 5 wt%, and 2.75 g of an acrylic resin (Hitaroid 1007, Hitachi Chemical Co., Ltd.) In the same manner as the mixed solvent of 43.1 g of isopropyl alcohol and n-butanol in a ratio of 1/1 (by weight), a substrate having a transparent coating film having a thickness of 100 nm of the coating liquid and the transparent film was obtained in the same manner (A) -8).

Example 9 Modulation of chain cerium oxide hollow microparticles (P-7)

After washing with an ultrafiltration membrane method and concentrating, 1,125 g of pure water was added to 500 g of a cerium oxide-alumina-coated chain-like composite oxide particle (P-1) dispersion having a solid concentration of 13% by weight, followed by dropping. Concentrated hydrochloric acid (concentration: 35.5 wt%) was brought to pH 0.5 and subjected to dealumination treatment. Next, 25 L of a hydrochloric acid aqueous solution of pH 3.0 and 10 L of pure water were added, and the dissolved aluminum salt was separated by an ultrafiltration membrane to obtain a chain-like cerium oxide-based hollow fine particle having a solid concentration of 20% by weight. (P-7) aqueous dispersion. (Step (e)) (Step (f))

Manufacture of substrate (A-9) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (P-7) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate of the film (A-9).

Comparative example 1 Modulation of yttrium oxide hollow microparticles (RP-1)

100 g of cerium oxide ‧ alumina sol (made by Nikko Catalyst: USBB-120, average particle size 25 nm, SiO ₂ ‧ Al ₂ O ₃ concentration 20% by weight, solid content Al ₂ O ₃ content 27 weight %) 3900 g of pure water was added, heated to 98 ° C, while maintaining this temperature, 1750 g of an aqueous solution of sodium citrate having a concentration of 1.5 wt% of SiO ₂ and 1750 g of Al ₂ O _{3 were} added over 6 hours. A 0.5% by weight aqueous sodium aluminate solution was obtained to obtain a SiO ₂ ‧ Al ₂ O ₃ primary particle (P-1) dispersion. The molar ratio at this time is MO _x /SiO ₂ =0.2. Further, the pH of the reaction liquid at this time was 12.0. The primary particle average particle diameter of this dispersion was 35 nm. (Step (a))

Next, an ultrafiltration membrane method to wash SiO ₂ ‧Al ₂ O ₃ primary particles (P-1) dispersion liquid, and was concentrated to a solid content concentration of 5 wt% of SiO ₂ ‧Al ₂ O ₃ primary particles (P-1 )Dispersions. (Step (b))

Subsequently, 3900 g of pure water was added to 300 g of a SiO ₂ ‧Al ₂ O ₃ primary particle (P-1) dispersion having a solid concentration of 5 wt%, and the mixture was heated to 98 ° C while maintaining the temperature for 17 hours. 1530 g of an aqueous solution of sodium citrate as a concentration of SiO ₂ of 1.5% by weight and 500 g of an aqueous solution of sodium aluminate having a concentration of 0.5% by weight of Al ₂ O ₃ were added to obtain cerium oxide-alumina-coated composite oxide particles ( RP-1) dispersion.

Next, it was washed by an ultrafiltration membrane method and concentrated, and 1,125 g of pure water was added to 500 g of a cerium oxide-alumina-coated composite oxide particle (RP-1) dispersion having a solid concentration of 13% by weight, followed by dropping. Concentrated hydrochloric acid (concentration: 35.5 wt%) was brought to pH 1.0 and subjected to dealumination treatment. Next, 10 L of a hydrochloric acid aqueous solution of pH 3 and 5 L of pure water were added, and the dissolved aluminum salt was separated by an ultrafiltration membrane to obtain monodisperse cerium oxide-based hollow fine particles (RP) having a solid concentration of 20% by weight. -1) Aqueous dispersion. The cerium oxide-based hollow fine particles (RP-1) in the aqueous dispersion are neither chained nor aggregated.

Manufacture of substrate (RA-1) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of cerium oxide-based hollow fine particles (RP-1) having a solid concentration of 20% by weight was used, a transparent coating film having a thickness of 100 nm of the coating liquid and the transparent coating was obtained in the same manner. Substrate (RA-1).

Comparative example 2 Modulation of chain cerium oxide hollow microparticles (RP-2)

In the first embodiment, the step (c) was carried out in the same manner except that 140 g of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte was mixed. At this time, since the aggregated particles are obtained, the subsequent steps are not carried out.

Comparative example 3 Modulation of chain cerium oxide hollow microparticles (RP-3)

In the same manner as in Example 1, except that 0.1 g of a Ca(NO ₃ ) ₂ aqueous solution having a concentration of 10% by weight as an electrolyte was mixed, a chain cerium oxide-based hollow fine particle (RP-3) having a solid concentration of 20% by weight was obtained in the same manner. Water dispersion. However, most of them are monodisperse cerium oxide-based hollow fine particles similar to those of Comparative Example 1. The physical properties of the chain cerium oxide-based hollow fine particles (RP-3) were measured in the same manner as in Example 1, and the results are shown in Table 1.

Manufacture of substrate (RA-3) with transparent film

In the same manner as in Example 1, except that an aqueous dispersion of chain cerium oxide-based hollow fine particles (RP-3) having a solid concentration of 20% by weight was used, a coating liquid and a transparent film having a thickness of 100 nm were obtained in the same manner. The substrate of the film (RA-3).

Comparative example 4 Manufacture of substrate with transparent film (RA-4)

For cerium oxide sol (made by Catalyst-Chemical Co., Ltd.: Cataloid-SI-45P, average particle size: 45 nm, SiO ₂ concentration: 40% by weight), an ultrafiltration membrane was used, and the solvent was replaced with ethanol to prepare a solid concentration of 5 parts by weight. % of cerium oxide organosol.

50 g of a cerium oxide organosol having a solid concentration of 5 wt%, 3 g of an acrylic resin (Hitaroid 1007, manufactured by Hitachi Chemical Co., Ltd.), and 47 g of isopropanol mixed with 1/1 (by weight) of n-butanol were thoroughly mixed. Solvent to prepare a coating solution.

This coating liquid was applied onto a PET film by a bar coating method, and dried at 80 ° C for 1 minute to obtain a transparent film-attached substrate (RA-4) having a transparent film thickness of 100 nm.

Fig. 1 is a model diagram showing a cross section of a chain-like cerium oxide-based hollow fine particle of the present invention.

Claims (12)

A chain-shaped yttria-based hollow fine particle which is a chain-shaped yttria-based hollow fine particle having a shell and a ruthenium-based hollow fine particle (primary particle) having a cavity inside and having a chain shape, and is characterized by a link The through-holes of the yttrium oxide-based hollow microparticles have a mean length (L) in the range 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 ratio of the average diameter (D _s ) of the pores to the aforementioned average width (W) (D _s )/(W) is in the range of 0.1 to 0.9. The chain cerium oxide hollow fine particles according to claim 1, wherein the thickness (T _s ) of the outer shell is in the range of 2 to 100 nm, and the ratio of the average width (W) (T _s ) / (W) In the range of 0.05~0.30. The chain-shaped yttria-based hollow fine particles according to the first or second aspect of the patent application, wherein the chain-shaped yttria-based hollow fine particles are composed of an inorganic oxide other than cerium oxide and cerium oxide, and other than cerium oxide represented by MO _x In the case of an inorganic oxide, the molar ratio (MO _x /SiO ₂ ) is in the range of 0.0001 to 0.2, where M in the MO _x represents an element which produces an inorganic oxide with an oxygen atom, and _x represents the atomic number of oxygen, and Among the chain cerium oxide-based hollow fine particles, examples of the inorganic oxide other than cerium oxide include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , Ce ₂ O ₃ , P ₂ O ₅ , and Sb. 1 or 2 or more of ₂ O ₃ , MoO ₃ , ZnO ₂ , and WO ₃ . A method for producing a chain-like cerium oxide-based hollow fine particle, comprising the following steps (a) to (f), (a) dispersing a seed particle in an aqueous alkali solution or a solid concentration in a range of 0.01 to 2% by weight; In the aqueous alkali solution, at least one of an aqueous solution of a citrate and an acidic citric acid solution is simultaneously added with an aqueous solution of an alkali-soluble inorganic compound to prepare a molar ratio A (=MO _x /SiO ₂ , when oxidized by SiO ₂矽, when MO _x represents an inorganic oxide other than cerium oxide) a step of a primary particle dispersion of a composite oxide in the range of 0.1 to 2 (wherein M in the MO _x represents an inorganic oxide with an oxygen atom) The element, _x represents the atomic number of oxygen, and (b) the step of washing the primary particle dispersion, and (c) the washed primary particle dispersion in the presence of an electrolyte at 50 to 300 ° C. And hydrothermal treatment to prepare a step of the primary particle chain-connected chain-like composite oxide particle dispersion of the composite oxide, and (d) providing a cerium oxide coating layer or cerium oxide on the surface of the chain-like composite oxide particle. a step of preparing a coating layer of the chain-like composite oxide particles with a coating layer on the alumina coating layer, and adding an acid to the dispersion liquid of the chain-like composite oxide particles having the coating layer, and removing the composite oxidation The step of producing a chain-shaped cerium oxide-based hollow fine particle dispersion liquid and at least (f) washing the chain-shaped cerium oxide-based hollow fine particle dispersion liquid, at least a part of the elements other than the primary particles of the material. Chain oxidized cerium hollow particles as claimed in item 4 of the patent application A method for producing a sub-organic metal salt as the electrolyte in the step (c). The method for producing a chain cerium oxide-based hollow fine particle according to the fourth aspect of the invention, wherein the step (f) is followed by the following step (g): (g) the chain-shaped cerium oxide-based hollow fine particles The dispersion is subjected to a hydrothermal treatment step in the range of 50 to 300 °C. The method for producing a chain yttria-based hollow fine particle according to the fourth aspect of the invention, wherein the element other than the foregoing lanthanum in the step (e) is removed to a molar ratio A (=MOx/SiO ₂ ) to be 0.0001 to 0.2. The scope is up to now. The method for producing a chain-like cerium oxide-based hollow fine particle according to any one of the items (4), wherein in the step (d), the chain-like composite oxide particle dispersion obtained in the step (c), a step of forming an cerium oxide coating layer on the chain-like composite oxide particles by adding an aqueous alkali solution and an organic hydrazine compound represented by the following chemical formula (1) and/or a partial hydrolyzate thereof, R _n SiX _(4-n) ‧‧‧(1) [R, R: an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, an alkylene group, an epoxy group, a methacryl group, an amine group or a CF ₃ group; X: a carbon number of 1~ Alkoxy, stanol, halogen or hydrogen; n: an integer from 0 to 3. The method for producing a chain-like cerium oxide-based hollow fine particle according to any one of the items (4), wherein in the step (d), the chain-like composite oxide particle dispersion obtained in the step (c), Adding alkali The aqueous solution and the acidic citric acid solution form a ruthenium oxide coating layer on the chain-like composite oxide particles. The method for producing a chain-like cerium oxide-based hollow fine particle according to any one of the items (4), wherein in the step (d), the chain-like composite oxide particle dispersion obtained in the step (c), Adding an aqueous solution of citric acid and an aqueous solution of aluminate to form cerium oxide on the aforementioned chain-like composite oxide particles. The step of coating the alumina. A coating liquid for forming a transparent film, which comprises the chain-like cerium oxide-based hollow fine particles of the first aspect of the patent application and a matrix-forming component. A substrate comprising a transparent film, which is characterized in that the transparent film formed by the coating liquid for forming a transparent film of claim 11 is formed on the surface of the substrate alone or together with another film.