JP2006306708A - Titanium-containing silica sol and its manufacturing method, and application of titanium-containing silica sol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material which can be simply applied to a base material, can be applied to a wide variety of base materials and at the same time, can form an antifouling film having excellent antifouling properties. <P>SOLUTION: The material is titanium-containing silica sol characterized by comprising (a) fine particles which are fine particles (a1) or (a2) where (a1) is titania fine particles having an average particle diameter of 2 to 50 nm and non-porous silica fine particles having an average particle diameter of 5 to 100 nm and a specific surface area of ≥30 m<SP>2</SP>/g and <550 m<SP>2</SP>/g as determined by the BET method or (a2) is non-porous silica fine particles comprising non-porous silica fine particles having an average particle diameter of 5 to 100 nm and a specific surface area of ≥30 m<SP>2</SP>/g and <550 m<SP>2</SP>/g as determined by the BET method and the surface of the non-porous silica fine particles having been modified with a titanate compound and (b) a dispersion medium. In the titanium-containing silica sol, the content of Si and Ti which constitute the (a1) or the (a2) is in a range of 5-21,000 expressed in terms of SiO<SB>2</SB>/TiO<SB>2</SB>weight ratio. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fine particle filler as a raw material for a general-purpose antifouling film forming composition that can be applied in a wide range from ship bottoms, ceiling materials to dredging, and more specifically, metal, glass, wood, plastic The present invention relates to a titanium-containing silica sol as a raw material for a composition for forming an antifouling film applied to the surface of a substrate made of ceramics, paper, or the like, and a method for producing the same.

  The present invention also relates to a substrate with an ink receiving layer in which an ink receiving layer is formed on a substrate used for printing a resin film sheet such as PET or vinyl chloride, paper, steel plate, cloth or the like. Furthermore, the present invention relates to a method for regenerating a substrate.

  Underwater structures such as ship bottoms and fishing nets are used for a long period of time in water, especially in seawater, so there are many underwater structures such as Aosa (green algae plants) in contact with the underwater structures and seawater. Living organisms may adhere and propagate, leading to a reduction in ship fuel economy and a decline in the original functions of fishing nets.

  In order to solve such a problem, an antifouling agent is applied to the surface of a ship bottom or a fishing net for the purpose of preventing adhesion of marine organisms. Specifically, an antifouling composition in which a color developing agent such as a hydrolyzable resin for properly eluting the antifouling agent is mixed with an organic antifouling agent is widely used. Further, a color developing agent having antifouling property, such as room temperature curable silicone rubber, is also used as an antifouling agent. However, satisfactory antifouling properties are not obtained with these antifouling agent compositions.

  In addition, glass, metal, wood, plastic, and paper are often used as various materials such as ceiling materials, wall materials, floor materials, and firewood. During use, mainly dust, oil smoke, sebum, etc. There is a tendency for organic soiling substances to adhere and fade the original color. For the purpose of facilitating the decomposition of the dirt adhering to the surface of these materials, for example, a method of coating a fluorine resin, a method of applying a silicone resin, an acrylic resin, a urethane resin, a fluorine-based paint or the like has been proposed.

Patent Document 1 (JP 2001-72869), and a polysiloxane block, acrylic resin _{block, -M-OCO- (GCOO) r} - a [M represents a divalent metal atom - (CH _{2) p} G represents a divalent hydrocarbon group, r represents 0 or 1, and p represents an integer of 0 to 5. And the metal-containing bond is present between the polysiloxane block and the acrylic resin block, or is present in the acrylic resin block and has a specific intrinsic viscosity. There is a description of a block copolymer having [η] and a composition for forming an antifouling film comprising the block copolymer, and according to the composition for forming an antifouling film, shellfish such as algae and mussels, etc. It is described that a coating film exhibiting excellent antifouling property against aquatic organisms can be formed on the surface of a substrate such as a fishing net. Moreover, according to the antifouling treatment method for a base material described in Patent Document 1, the antifouling agent composition is impregnated and applied to the surface of the base material that comes into contact with seawater. It is described that a film can be formed automatically.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2001-19848) discloses an invention relating to a composition for forming an antifouling film containing a polyoxyalkylene-modified silicone in a specific hydrophilic / lipophilic balance range. According to the antifouling treatment method for a base material according to the present invention, the surface of the base material that comes into contact with seawater or fresh water, or the surface of a fishing gear, a fishing net, an underwater structure, etc. to which the antifouling film forming composition is applied is algae. It is described that it is possible to effectively prevent such adhesion.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 9-227804) discloses a polymer containing a unit obtained by polymerizing an acrylate having a polyfluoroalkyl group and / or a methacrylate having a polyfluoroalkyl group, and a polyurethane containing no isocyanate group. An antifouling coating agent having an antifouling effect containing a compound in an aqueous medium is disclosed. According to the antifouling coating agent, an excellent antifouling property against various stains on a substrate surface can be obtained by a simple treatment method. It is described that a film having soiling properties can be formed, and the obtained film has not only antifouling properties but also excellent hardness and appearance.

  Patent Document 4 (Japanese Patent Application Laid-Open No. 2000-34422) discloses a resin material obtained by graft-polymerizing a specific silicone resin in the presence of dicyclohexylcarbodiimide in a thermosetting polymerizable unsaturated ester resin material. The invention to be used as is disclosed, and the use of a cured product obtained from this aqueous soil adhesion preventing resin material and a polyisocyanate compound as an antifouling coating against aqueous soil is described.

  Patent Document 5 (Japanese Patent Application Laid-Open No. 2000-342359) discloses a technique related to an antifouling coating comprising a graft polymer of a thermosetting polymerizable unsaturated ester and a silicone resin. It is described that when applied to a base material such as synthetic resin, wood, ceramics or glass, the organic solvent can be evaporated and scattered to form an antifouling coating.

  Patent Document 6 (Japanese Patent Application Laid-Open No. 2000-192021) discloses a metal oxide film coated on the surface of a substrate, which has irregularities of 25 to 100 nm in the height direction and a pitch of 10 to 100 microns. An invention relating to a hydrophilic and anti-fogging and antifouling base material characterized by having a surface shape of the same has been disclosed, and the metal oxide film has high hardness and excellent transparency and maintains antifouling performance over a long period of time. It is described that it is possible. As a method for producing such a hydrophilic / anti-fogging / anti-fouling substrate, an organic metal compound for forming a matrix and ultrafine particles exhibiting water absorption and / or photocatalytic activity are added to a solvent and uniformly mixed by stirring. The solution is applied to the surface of the substrate, subjected to hydrolysis and condensation polymerization, and then dried and fired (350 to 700 ° C.) to form a metal oxide film having regular irregularities on the surface of the substrate. A method is disclosed.

However, the application method to a base material is simple, it can be applied to a wide range of base materials, and the appearance of a material capable of forming an antifouling film having excellent antifouling performance has been desired.
On the other hand, as a technique for erasing the printing on the surface of the substrate, the following techniques are known, for example.

  First, Patent Document 7 (Japanese Patent Application Laid-Open No. 11-235863) discloses (i) hydrolysis of photocatalytic titanium oxide fine particles having an average particle diameter of 0.05 to 0.2 μm, (ii) alkyl silicate, silicon halide, and the like. The coloring material of the printed part is ultraviolet rays on a substrate coated with a clear coating composition comprising a functional silicon compound or a hydrolyzate of the silicon compound and / or a partial condensate of the hydrolyzable silicon compound and (iii) a solvent. There is disclosed a method for regenerating a printing substrate characterized in that printing is carried out using an ink composition comprising a dye that is decolored by irradiation of the ink, and ultraviolet rays are irradiated to the printed matter thus obtained to decolor the printed portion. Yes.

  In Patent Document 8 (Japanese Patent Application Laid-Open No. 11-335599), printing is performed using an ink composition containing photocatalytic anatase-type titanium oxide fine particles having an average particle diameter of 0.05 to 0.2 μm on a substrate, and thus There is disclosed a method for regenerating a printing substrate, wherein the printed matter obtained is irradiated with ultraviolet rays to erase the printed portion.

Patent Document 9 (Japanese Patent Application Laid-Open No. 2004-237538) is provided with a reversible recording layer that forms a colored and decolored state by applying thermal energy at least on a support. A reversible recording medium used for visually recognizing a color image formed on a reversible recording layer from the support surface side, and supporting the image so that the image formed on the recording layer can be recognized from the support side. A reversible recording medium is disclosed in which the body is transparent and the haze value is 90% or more, and the recording layer or the concealing layer may contain titanium oxide particles. It is described that it is good.

However, there has been a demand for the emergence of a technology that is further excellent in the performance of erasing the printing on the surface of the base material, has a simple application method to the base material, and can be applied to a wide range of base materials.
JP 2001-72869 A Japanese Patent Laid-Open No. 2001-19848 JP-A-9-227804 JP 2000-34422 A JP 2000-342359 A JP 2000-192021 A JP 2000-34422 A JP-A-11-335599 JP 2004-237538 A

  The present invention is intended to solve the above-mentioned problems, and the application method to the substrate is simple, applicable to a wide range of substrates, and excellent antifouling performance. It aims at providing the material which can form the antifouling film which has.

It is another object of the present invention to provide a substrate with an ink receiving layer capable of decoloring printing or printing by ink jet printing or the like and a method for producing the same.
Another object of the present invention is to enable reuse of a printed or printed substrate.

  As a result of intensive studies to solve the above problems, the present inventors have determined that specific fine particles, that is, titania fine particles and nonporous silica fine particles (a1), or nonporous silica fine particles obtained by surface modification with titanate compounds ( It has been found that when a titanium-containing silica sol containing a2) is used, an excellent antifouling coating can be formed, and the present invention has been completed.

The titanium-containing silica sol according to the present invention is
(A) the following fine particles (a1) or fine particles (a2);
(A1) Titania fine particles having an average particle diameter of 2 to 50 nm and nonporous silica having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g Fine particles,
(A2) The surface of the nonporous silica fine particles having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g is surface-modified with a titanate compound. Non-porous silica fine particles,
(B) containing a dispersion medium,
The content of Si and Ti constituting the titania fine particles and the non-porous silica fine particles (a1) or the non-porous silica fine particles (a2) obtained by surface modification with the titanate compound is in a SiO ₂ / TiO ₂ weight ratio. It is characterized by being in the range of 5 to 21,000 in terms of conversion.

The titanate compound is preferably represented by any one of the following general formulas (1) to (3).
R ¹¹ _n TiR ¹² _4-n (1)
[Where n is an integer of 1 to 4.

R ¹¹ is an alkoxy group having 1 to 6 carbon atoms, and when n = 2 or 3, two R ¹¹ 's may combine to form a ring structure represented by the following general formula (1a). Furthermore, two hydrogen atoms bonded to one of the carbon atoms adjacent to the oxygen atom in the general formula (1a) are substituted with an oxygen atom to form a ring structure represented by the following general formula (1b). May be.

R ¹² is a hydrocarbon group having 1 to 5 carbon atoms or an organic group represented by the following general formula (1c), (1d), (1e), (1f), (1g) or (1h).

    (However, x is an integer of 1-7.)

    (However, y is an integer of 1-7.)

    (However, p is an integer of 4 to 30.)

    (However, q is an integer of 4 to 30.)

    (However, q 'is an integer of 4 to 30.)

    (However, r and r 'are each an integer of 1 or more, and r + r' is 4 to 30.)

    (However, s is an integer of 1-30.)

(However, t and t ′ are each an integer of 1 to 30.)]
R ²¹ TiR ²² R ²³ ₂ (2)
[Wherein R ²¹ is an alkoxy group having 1 to 4 carbon atoms, R ²² is an organic group represented by the following general formula (2a), and R ²³ is an organic group represented by the following general formula (2b). It is a group.

    (However, u is an integer of 4 to 30.)

(However, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)]
R ³¹ ₄ Ti · [P (OC _2w H _{2w + 1} ) ₂ (OH)] ₂ (3)
[Wherein R ³¹ is an alkoxy group having 1 to 20 carbon atoms,
Some of the hydrogen atoms in the alkoxy group have 4 to 12 carbon atoms and may be substituted with an organic group having at least one of an ether bond and a double bond.

w is an integer of 4-20. ].
The surface charge amount of the non-porous silica fine particles is preferably in the range of 10 to 150 μeq per 1 g of the fine particles.

  The method for producing a titanium-containing silica sol containing the fine particles (a1) according to the present invention includes a titania sol containing the titania fine particles and the dispersion medium (b), and the non-porous silica fine particles and the dispersion medium (b). It is characterized by mixing silica sol containing.

  The method for producing a titanium-containing silica sol containing the fine particles (a2) according to the present invention is characterized by adding a titanate compound to the silica sol containing the non-porous silica fine particles and the dispersion medium (b). .

  In the composition for forming an antifouling film according to the present invention, a binder (c) selected from organic resins, celluloses, starches and inorganic compounds is dispersed in the titanium-containing silica sol.

The coating liquid for forming an ink receiving layer according to the present invention comprises a binder (c ′) selected from a hydrophilic polymer and celluloses dispersed in the titanium-containing silica sol.
Further, the coating liquid for forming an ink receiving layer according to the present invention comprises:
100 parts by weight of the fine particles (a1) or the fine particles (a2) and 5 to 150 parts by weight of the binder (c ′),
The weight (W _B ) of the dispersion medium (b), the fine particles (a1) or the fine particles (a2),
And the ratio to the total weight (W _A + W _{C ′} ) of the binder (c ′) is W _B : (W _A + W _{C ′}
) = 99.9-50: 0.1-50 (where the total is 100),
The content of Si and Ti constituting the fine particles (a1) or the fine particles (a2) is preferably in the range of 5 to 21,000 in terms of the SiO ₂ / TiO ₂ weight ratio.

  A first method for producing an ink-receiving layer-forming coating liquid according to the present invention includes a titanium-containing silica sol (a1s) in which the titania fine particles and the non-porous silica fine particles (a1) are dispersed in the dispersion medium (b), The binder (c ′) and, if necessary, the dispersion medium (b) are further mixed.

  In the second production method of the ink receiving layer forming coating liquid of the present invention, the nonporous silica fine particles (a2) obtained by modifying the surface with a titanate compound are dispersed in the dispersion medium (b). The titanium-containing silica sol (a2s), the binder (c ′) and, if necessary, the dispersion medium (b) are further mixed.

The substrate with an ink receiving layer of the present invention is
(A1) Titania fine particles having an average particle diameter of 2 to 50 nm and nonporous silica having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g Fine particles, or (a2) The average particle diameter is 5 to 100 nm, and the specific surface area determined by the BET method is 30 m ^2.
An ink receiving layer containing non-porous silica fine particles formed by surface-modifying the surface of non-porous silica fine particles having a particle size of / g or more and less than 550 m ² / g with a titanate compound is formed.

The method for producing a substrate with an ink receiving layer of the present invention is characterized in that the ink receiving layer forming coating solution is applied to the surface of the substrate and then dried.
In the method for regenerating a substrate according to the present invention, printing is performed with ink on the substrate with an ink receiving layer to form a print or print, and then the print or print is formed by ultraviolet irradiation, contact with acid gas or ozone. The feature is to erase the color.

  When the titanium-containing silica sol of the present invention is used, it is possible to easily form an antifouling film on the surface of metal, glass, wood, plastic, ceramics, paper, etc., and this antifouling film exhibits an excellent antifouling effect. To do. When this antifouling coating is applied to the ship bottom surface, it is possible to suppress adhesion of green algae.When it is applied to the surface of ceiling materials, wall materials, papers, etc., dust, Even if mainly organic soil substances such as oily smoke and sebum adhere, the soil substances on the substrate surface can be decomposed by ultraviolet irradiation or contact with acid gas. If the base material is a wall material or paper, a decomposition effect is exerted on dirt written with ink or the like such as so-called graffiti, and dirt can be eliminated.

  The recording substrate with the ink-receiving layer of the present invention produced by applying and drying the ink-receiving layer-forming coating liquid of the present invention, ink-jet printing or printing is performed with ultraviolet irradiation, acid gas, or ozone. It can be erased by contact.

  Further, by using the substrate recycling method of the present invention, it is possible to suppress mass consumption of paper such as plain paper and copy paper and printing substrate such as an OHP sheet.

  Hereinafter, the titanium-containing silica sol according to the present invention, its production method, and its use will be described in detail. In the present specification, “antifouling” means both prevention of adhesion of the dirt substance itself and decomposition of the attached dirt substance unless otherwise specified.

Further, in the present invention, the printing or printing or the like printed on the surface of the substrate with the ink receiving layer may be erased by irradiating with ultraviolet rays or contacting with acid gas or ozone. “Decolorization” and such characteristics are called “decolorization”.

[Titanium-containing silica sol]
The titanium-containing silica sol according to the present invention comprises (a) (a1) titania fine particles and non-porous silica fine particles or (a2) non-porous silica fine particles obtained by surface modification with a titanate compound, and (b) a dispersion medium. Contains.

<Titanium-containing silica sol containing titania fine particles and non-porous silica fine particles (a1) and a dispersion medium (b)>
(A1) titania fine particles and non-porous silica fine particles;
Titania fine particles:
The titania fine particles used in the present invention exhibit a catalytic action on the redox reaction of organic matter when irradiated with light having a specific energy such as ultraviolet rays. The titania fine particles may be either amorphous titania fine particles or crystalline titania fine particles. If crystalline titanium dioxide, the crystalline form may be any of anatase type, rutile type or brookite type, or a mixture thereof. But you can. In the present invention, the titania fine particles are mixed, for example, in a titania sol with a silica sol in which non-porous silica fine particles to be described later are dispersed.

  The average particle diameter of the titania fine particles is 2 to 50 nm, preferably 5 to 40 nm. If the average particle size is smaller than this range, the dispersion stability of the titania sol or the titanium-containing silica sol is deteriorated. If the average particle size is larger than this range, the transparency of the antifouling film formed using the titanium-containing silica sol is lowered. In addition, the surface of the base material to which the antifouling coating is applied may deteriorate in appearance such as dullness or the photocatalytic function of the titania fine particles may not be sufficiently exhibited.

  If the titanium-containing silica sol is used as a raw material for the ink-receiving layer-forming coating liquid, the titania sol, the titanium-containing silica sol, or the ink-receiving layer-forming coating is used when the average particle diameter of the titania fine particles is smaller than this range. The dispersion stability of the liquid may deteriorate, and if the average particle size is larger than this range, the transparency of the substrate surface with the ink receiving layer is lowered, so that the surface of the substrate with the ink receiving layer becomes dull. The appearance may be deteriorated, or the decoloring effect based on the photocatalytic function of the titania fine particles may not be sufficiently exhibited.

The specific surface area of the titania fine particles is not particularly limited, and any titania fine particles having an average particle diameter in the above range can be applied to the present invention.
The particle properties of the titania fine particles are not particularly limited, and may be either spherical particles or non-spherical particles, or may be porous particles.

  As the starting material of the titania sol in which the titania fine particles are dispersed, titanium compounds such as titanium sulfate and titanium chloride, powdered titania whose crystal form is anatase type and / or rutile type, brookite type, and the like are used. When using a titanium compound or titania powder having an average particle size larger than 2 to 50 nm as a starting material, they are used by pulverizing them to reduce the particle size. As such titania powder, commercially available ultrafine titanium oxide can be used as it is or after being baked.

Non-porous silica fine particles:
In the present invention, the “non-porous silica fine particles” are silica fine particles that do not have a so-called porous structure. When the shape is assumed to be a true sphere, the density (ρ) is approximately 2.2 [g / cm ^3]. And the relational expression: SA = 6,000 / (Dp × ρ) (Dp is the particle diameter [μm] and SA is the specific surface area [m ² ]). Table 1 below shows the relationship among the density, particle diameter, and specific surface area of the non-porous silica fine particles used in Examples described later.

Porous silica fine particles used in the present invention has a specific surface area determined by BET method is 30 m ² / g or more and less than 550 meters ² / g, preferably from 33~400m ² / g. Contains a titanium-containing silica sol containing non-porous silica fine particles having a specific surface area in such a range and the titania fine particles, and non-porous silica fine particles obtained by surface-modifying the non-porous silica fine particles with a titanate compound. The antifouling film comprising the titanium-containing silica sol can exhibit an excellent antifouling effect by ultraviolet irradiation or contact with acid gas or ozone.

  Further, a titanium-containing silica sol (a1s) containing non-porous silica fine particles having a specific surface area in such a range and the titania fine particles, and surface modification of the non-porous silica fine particles, which will be described in detail later, with a titanate compound. The ink receiving layer formed using the coating solution for forming an ink receiving layer containing the titanium-containing silica sol (a2s) containing the non-porous silica fine particles is excellent by ultraviolet irradiation or contact with an acidic gas. It is possible to exert a decoloring effect.

  The average particle diameter of the non-porous silica fine particles is 5 to 100 nm, preferably 6 to 90 nm. If the average particle size is smaller than this range, the dispersion stability of the sol in which the non-porous silica fine particles are dispersed or the titanium-containing silica sol tends to be low, and if larger than this range, the titanium-containing silica sol is used. As the antifouling film formed is reduced in transparency, the surface of the substrate on which the antifouling film is formed deteriorates in appearance, or the photocatalytic function of the titania fine particles coexisting with the non-porous silica fine particles is sufficient. May not be demonstrated.

  Further, if the titanium-containing silica sol is used as a raw material for an ink-receiving layer-forming coating solution, if the average particle diameter is smaller than this range, the sol in which the non-porous silica fine particles are dispersed, the titanium-containing silica sol Alternatively, the dispersion stability of the ink-receiving layer-forming coating liquid tends to be low, and if it is larger than this range, the transparency of the ink-receiving layer to be formed decreases, so that the appearance of the substrate with the ink-receiving layer is reduced. In some cases, deterioration occurs, or the decoloring effect based on the photocatalytic function of titania fine particles coexisting with the non-porous silica fine particles may not be sufficiently exhibited.

The surface charge amount of the non-porous silica fine particles is preferably 10 to 150 μeq / g. When the surface charge amount is less than 10 μeq / g, the sol in which the non-porous silica fine particles are dispersed or the titanium-containing silica sol of the present invention tends to be unstable, and when it exceeds 150 μeq / g, the viscosity of the sol The antifouling film-forming composition containing the non-porous silica fine particles as a main component also has a high viscosity, making it difficult to form a uniform film.

  When such non-porous silica fine particles are used, not only a highly transparent film can be formed, but also a sol containing the non-porous silica fine particles and a titania sol are mixed, applied to a substrate and dried to form a film. At the time of formation, since the surface charge amount of the non-porous silica fine particles is large, the fine particles in the sol are difficult to aggregate, and a film is easily formed in a state where the titania fine particles are uniformly dispersed.

  Further, when the titanium-containing sol is used as a raw material for the coating liquid for forming an ink receiving layer, the surface charge amount is less than 10 μeq / g, the sol in which the non-porous silica fine particles are dispersed, and the titanium-containing The silica sol or the coating liquid for forming the ink receiving layer tends to be unstable, and when it exceeds 150 μeq / g, the viscosity of the sol in which the non-porous silica fine particles are dispersed or the titanium-containing silica sol tends to increase. Since the viscosity of the ink receiving layer forming coating solution containing the titanium-containing silica sol as a main component is increased, it is difficult to form a uniform film.

  On the other hand, when non-porous silica fine particles having a surface charge amount in the range of 10 to 150 μeq / g are used, a highly transparent ink receiving layer can be formed. Further, since the surface charge amount of the non-porous silica fine particles is appropriate, the fine particles are difficult to aggregate in the titanium-containing sol and the ink-receiving layer forming coating solution, and the titania fine particles are uniformly dispersed. Also in the ink receiving layer formed by applying and drying the ink receiving layer forming coating liquid on the substrate, the titania fine particles are sufficiently dispersed. As a result, the substrate with an ink receiving layer of the present invention exhibits good decoloring properties.

Production method of non-porous silica fine particles;
The production method of the non-porous silica fine particles used in the present invention is not particularly limited, and can be obtained in the form of silica sol by a known production method of silica sol.

  Various methods for producing silica sol have been proposed for a long time, and specifically, a dialysis method, an ion exchange resin method, an ion exchange membrane method, and the like are known. In these methods, it is difficult to directly obtain a high-concentration silica sol. Usually, a low-concentration silica sol having a concentration of about 2 to 4% by weight is generated, stabilized, and then concentrated to a practical concentration. is required.

  As a concentration method, a so-called evaporative concentration method is generally known in which a dilute silica sol is heated to remove moisture, but has a drawback that it requires energy costs and equipment costs for concentration. On the other hand, a concentration method using an ultrafiltration method is already known. For example, Japanese Patent Application Laid-Open No. 58-110416 discloses an example thereof. The ultrafiltration method is considered to be advantageous in the energy cost and equipment cost of the concentration compared to the evaporation concentration method. Regardless of which concentration method, evaporative concentration method or ultrafiltration method is employed, it is desired to obtain a silica sol that is initially produced at a high concentration.

  In contrast to the method of obtaining a stable silica sol without gelation at a low concentration as described above, the silica hydrogel is peptized in the presence of a peptizer to obtain a silica sol with a higher concentration than the above method. The method of obtaining is also proposed.

In Japanese Patent Publication No. 48-31839, sodium silicate is once gelled with an ion exchange resin or sulfuric acid, and 1 to 5 mol% of alkali hydroxide or ammonium hydroxide as a peptizer is added to SiO ₂ to peptize. A method for obtaining a silica sol has been proposed. For example, in the embodiment, the SiO ₂ by adding 14 wt% aqueous ammonia solution to 14.5 wt% gels for 7 wt% of SiO ₂ hydrogels containing NH ₃ 2.7 mol%, Peptization under pressure of 7 kg / cm ^{3 in} an autoclave. Therefore, it is considered that the concentration of the generated silica sol is about 7% by weight.

  Japanese Patent Application Laid-Open No. 47-42297 describes that after acidified silica hydrogel is washed with weakly acidic water, it contains 5 to 8% silica and ammonium hydroxide is 0.75 to 2.5% in terms of ammonia concentration. A method of heating a silica hydrogel containing 70 to 100 ° C. is disclosed. According to this method, a silica sol having a silica concentration of about 4.5% by weight is obtained in the example.

  Furthermore, a so-called build-up method in which an alkaline low molecular weight silica sol is used as a seed, an acidic silicic acid solution is added thereto, and silica particles are formed to obtain silica sol containing silica particles having a predetermined particle diameter. The production method of silica sol by is well known, and various methods have already been proposed. For example, in the Japanese Patent Application Laid-Open No. 63-45114, the inventors of the present application prepared an acidic silicic acid solution obtained by preparing seed particles and dealkalizing an alkali metal silicate aqueous solution such as water glass with an ion exchange resin or the like. A method is disclosed in which silica sol is produced by adding and laminating, depositing, and depositing acidic silicic acid on the surface of seed particles to grow seed particles.

  In addition, as a method for producing a high-purity silica sol, a method using an alkoxysilane with few impurities as a starting material is known. JP-A-6-316407 discloses a method in which an alkyl silicate is hydrolyzed in the presence of an alkali. Discloses a method for obtaining a silica sol by polymerizing the produced silicic acid. Japanese Patent Application Laid-Open No. 2001-2411 discloses a method of obtaining an aqueous silica sol by hydrolyzing an alkoxysilane in an acidic solvent and polymerizing a silicic acid monomer produced thereby in a basic solvent.

(B) a dispersion medium;
As the dispersion medium (b) used in the present invention, water;
Alcohols such as methanol, ethanol, isopropanol, n-butanol, methyl isocarbinol;
Ketones such as acetone, 2-butanone, ethyl amyl ketone, diacetone alcohol, isophorone, cyclohexanone;
Amides such as N, N-dimethylformamide and N, N-dimethylacetamide;
Ethers such as diethyl ether, isopropyl ether, tetrahydrofuran, 1,4-dioxane, 3,4-dihydro-2H-pyran;
Glycol ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, ethylene glycol dimethyl ether;
Glycol ether acetates such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate;
Esters such as methyl acetate, ethyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, ethylene carbonate;
Aromatic hydrocarbons such as benzene, toluene, xylene;
Aliphatic hydrocarbons such as hexane, heptane, iso-octane, cyclohexane;
Halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, dichloropropane, chlorobenzene;
Sulfoxides such as dimethyl sulfoxide;
Examples include pyrrolidones such as N-methyl-2-pyrrolidone and N-octyl-2-pyrrolidone. These dispersion media are selected, for example, according to the compatibility with the binder when preparing the composition for forming an antifouling film.

Moreover, these dispersion media may be used individually by 1 type, and may use 2 or more types together.
A method for producing a titanium-containing silica sol containing titania fine particles and non-porous silica fine particles (a1) and a dispersion medium (b);
The titanium-containing silica sol (titanium-containing silica sol (a1s)) containing the titania fine particles and non-porous silica fine particles (a1) and the dispersion medium (b) of the present invention is, for example, a mixture of titania fine particles and non-porous silica fine particles. Although it can also be obtained by dispersing in a dispersion medium, it is preferable that the titania sol contains titania fine particles having an average particle diameter of 2 to 50 nm and the dispersion medium (b), and the average particle diameter is 5 It is manufactured by mixing silica sol containing non-porous silica fine particles having a specific surface area of 30 m ² / g or more and less than 550 m ² / g and a dispersion medium (b), which is ˜100 nm and determined by the BET method. The

  From the viewpoint that the titanium-containing silica sol of the present invention can be produced by such an extremely easy operation, the fine particles (a1) (the titania fine particles and the non-porous silica fine particles) are used as the fine particles (a). preferable.

The weight ratio of Si in the non-porous silica fine particles and Ti in the titania fine particles used for this mixing is calculated as SiO ₂ / TiO ₂ = 5 to 21 in terms of the weight ratio of SiO ₂ and TiO _2. ,
000, preferably SiO ₂ / TiO ₂ = 100 to 16,000. Further, as will be described later, the weight ratio of Si and Ti in the titanium-containing silica sol of the present invention is set to SiO ₂ / T.
In the case of preparing iO ₂ = 8 to 16,000, the weight ratio of Si in the non-porous silica fine particles to Ti in the titania fine particles is SiO ₂ / TiO ₂ = 8 to 16,000. That's fine.

When SiO ₂ / TiO ₂ is less than 5, the transparency of the titanium-containing silica sol or the ink receiving layer described later tends to decrease. On the other hand, when SiO ₂ / TiO ₂ exceeds 21,000, the antifouling effect based on the photocatalytic action of the titania fine particles is weakened, so that the time required for the decomposition of the dirt tends to increase significantly. If the containing sol is used as a raw material for a coating liquid for forming an ink-receiving layer, the decoloring effect based on the photocatalytic action of the titania fine particles is weakened, and the time required for decoloring printing or printing tends to increase remarkably. It is in.

<Titanium-containing silica sol containing the surface-modified non-porous silica fine particles (a2) and the dispersion medium (b)>
(A2) Surface-modified non-porous silica fine particles:
In the non-porous silica fine particles (a2) (hereinafter also referred to as “surface-modified non-porous silica fine particles (a2)”) obtained by surface modification with a titanate compound used in the present invention, the non-porous silica fine particles For example, the surface is considered to be covered with a titania-based coating having a structure represented by the following formula (4), and this coating is considered to exhibit the same photocatalytic function as titania fine particles.

  As the titanate compound, a compound having a hydrolyzable group containing a Ti atom is used, and examples thereof include a tetraalkoxytitanium compound, a titanium acylate compound, a titanium chelate compound, and a titanate coupling agent. Among these, titanate compounds represented by any one of the following general formulas (1) to (3) are particularly preferable.

R ¹¹ _n TiR ¹² _4-n (1)
[Where n is an integer of 1 to 4.
R ¹¹ is an alkoxy group having 1 to 6 carbon atoms, and when n = 2 or 3, two R ¹¹ 's may combine to form a ring structure represented by the following general formula (1a). Furthermore, two hydrogen atoms bonded to one of the carbon atoms adjacent to the oxygen atom in the general formula (1a) are substituted with an oxygen atom to form a ring structure represented by the following general formula (1b). May be.

R ¹² is a hydrocarbon group having 1 to 5 carbon atoms or an organic group represented by the following general formula (1c), (1d), (1e), (1f), (1g) or (1h).

    (However, x is an integer of 1-7, preferably an integer of 1-3.)

    (However, y is an integer of 1 to 7, preferably an integer of 1 to 3.)

    (However, p is an integer of 4 to 30, preferably an integer of 5 to 20.)

    (However, q is an integer of 4 to 30, preferably an integer of 5 to 20.)

    (However, q 'is an integer of 4 to 30, preferably an integer of 5 to 20.)

    (However, r and r 'are each an integer of 1 or more, and r + r' is an integer of 4 to 30, preferably 4 to 20.)

    (However, s is an integer of 1 to 30, preferably an integer of 5 to 20.)

(However, t and t ′ are each an integer of 1 to 30, preferably an integer of 1 to 3.)]
R ²¹ TiR ²² R ²³ ₂ (2)
[Wherein R ²¹ is an alkoxy group having 1 to 4 carbon atoms, R ²² is an organic group represented by the following general formula (2a), and R ²³ is an organic group represented by the following general formula (2b). It is a group.

    (However, u is an integer of 4 to 30, preferably an integer of 5 to 20.)

(However, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)]
R ³¹ ₄ Ti · [P (OC _2w H _{2w + 1} ) ₂ (OH)] ₂ (3)
[Wherein R ³¹ is an alkoxy group having 1 to 20, preferably 2 to 10 carbon atoms,
A part of hydrogen atoms in the alkoxy group has 1 to 12 carbon atoms, preferably 4 to 8 carbon atoms, and may be substituted with an organic group having at least one of an ether bond and a double bond.

w is an integer of 4-20, preferably an integer of 5-20. ].
Examples of R ¹¹ include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a t-butoxy group.

Examples of R ¹² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a t-butyl group, an n-butyl group, and an n-pentyl group.
Examples of R ²¹ include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a t-butoxy group.

Examples of R ³¹ include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, t-butoxy group, substituted propoxy group, substituted butoxy and the like.

  Specific examples of such titanate compounds include isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphite) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetra (2,2-diallyl). Examples include oxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) tyrantitanate, isopropyltridodecylbenzenesulfonyl titanate, tetraisopropoxy titanate, and the like. .

The specific surface area determined by the BET method of the non-porous silica fine particles before being surface-modified with the titanate compound is 30 m ² / g or more and less than 550 m ² / g. Preferably it is 33-400 m < ² > / g. When the specific surface area is less than 30 m ² / g, the antifouling coating film described later may become white and the appearance may deteriorate, and excellent antifouling and decoloring effects based on photoactivity are exhibited. There is a tendency to become difficult. When the specific surface area is 550 m ² / g or more, the average particle size is 5
Below nm, the stability of the particles may be impaired.

  The average particle diameter of the nonporous silica fine particles before being surface-modified with the titanate compound is 5 to 100 nm, preferably 6 to 90 nm. When the average particle size is smaller than this range, the dispersion stability of the sol is lowered, and mixing with a binder or the like may be hindered. On the other hand, if it is larger than this range, the transparency of the antifouling film formed using the titanium-containing silica sol is lowered, and the surface of the substrate having the antifouling film may deteriorate in appearance such as dullness. In addition, the photocatalytic function may not be sufficiently exhibited.

  Furthermore, if the titanium-containing sol is used as a raw material for the ink-receiving layer-forming coating solution, the transparency of the ink-receiving layer formed using the titanium-containing silica sol is reduced, so that the ink-receiving layer is formed. The surface of the printed substrate may deteriorate in appearance such as dullness, or the decoloring function may not be sufficiently exhibited.

  The surface charge amount of the non-porous silica fine particles before being surface-modified with the titanate compound is preferably 10 to 150 μeq / g. When the surface charge amount is less than 10 μeq / g, the dispersibility of the sol tends to be unstable. When the surface charge amount exceeds 150 μeq / g, the viscosity of the sol increases, and the non-porous silica fine particles are contained as a main component. The viscosity of the composition for forming an antifouling film also increases, and it tends to be difficult to form a uniform film. In addition, the viscosity of the coating liquid for forming an ink receiving layer containing the non-porous silica fine particles as a main component increases, and it becomes difficult to form a uniform receiving layer.

(B) a dispersion medium;
As the dispersion medium (b), the above-described dispersion medium can be used.
A method for producing a titanium-containing silica sol containing the surface-modified nonporous silica fine particles (a2) and the dispersion medium (b);
The titanium-containing silica sol (titanium-containing silica sol (a2s)) containing the surface-modified non-porous silica fine particles (a2) and the dispersion medium (b) of the present invention disperses, for example, a mixture of titania fine particles and non-porous silica fine particles. Preferably, the average particle diameter is 5 to 100 nm, and the specific surface area determined by the BET method is 30 m ² / g or more and less than 550 m ² / g. It can be produced by adding a titanate compound to a silica sol containing porous silica fine particles and the dispersion medium (b), and preferably contains the non-porous silica fine particles and water or water and an organic dispersion medium. Obtained by adding the titanate compound at 15 ° C. or higher over 10 minutes to 2 hours while stirring the silica sol with a high-speed stirrer. Door can be. If the stirring is weak, the titanate compound may be hydrolyzed and aggregated.

Mixing ratio of the non-porous silica fine particle and a titanate compound, in terms of weight ratio of SiO ₂ and TiO _2, preferably SiO ₂ / TiO ₂ = 5~21,000, particularly preferably SiO ₂ / TiO ₂ = 100 to 16,000. Further, as will be described later, when the weight ratio of Si and Ti in the titanium-containing silica sol of the present invention is adjusted to SiO ₂ / TiO ₂ = 500 to 20,000, Si in the non-porous silica fine particles and The weight ratio with Ti in the titanate compound may be SiO ₂ / TiO ₂ = 500 to 20,000.

When SiO ₂ / TiO ₂ is less than 5, the transparency of the titanium-containing silica sol tends to decrease. On the other hand, when SiO ₂ / TiO ₂ exceeds 21,000, the degradation of the pollutant based on the photocatalytic action of the titania-based coating, that is, the antifouling effect is reduced, so that the time required for the degradation of the soil is remarkably increased. Tend to. Further, when the titanium-containing sol is used as a raw material for the ink receiving layer forming coating solution, the decoloring effect based on the photocatalytic action of the titania fine particles is weakened, and therefore the time required for decoloring of printing or printing is reduced. There is a tendency to increase significantly.

  Such surface-modified non-porous silica fine particles (a2) are excellent in photocatalytic action, and even if dirt which is an organic compound adheres to the surface of the base material on which the antifouling film containing the fine particles is formed, it is stained by ultraviolet irradiation. Is further decomposed, and dirt is also decomposed by contact with acid gas, ozone or the like.

  Further, such surface-modified non-porous silica fine particles (a2) are excellent in decoloring action based on photocatalytic action, and are printed or printed with ink on the surface of a printing substrate on which an ink receiving layer containing the fine particles is formed. However, the printed or printed image is decolored by irradiation with ultraviolet rays, and further decolored by contact with acid gas, ozone or the like.

<Titanium-containing silica sol>
The titanium-containing silica sol of the present invention contains the titania fine particles and non-porous silica fine particles (a1) or the surface-modified non-porous silica fine particles (a2), and the dispersion medium (b), which will be described later. It can be used as a titanium-containing silica sol blended in the antifouling film forming composition or the ink receiving layer forming coating solution.

The weight ratio of Si and Ti in the titanium-containing silica sol of the present invention is SiO ₂ / TiO ₂ = 5 to 21,000 in terms of the weight ratio of SiO ₂ and TiO ₂ , preferably SiO _2.
/ TiO ₂ = 100 to 16,000.

When SiO ₂ / TiO ₂ is less than 5, the transparency of the titanium-containing silica sol tends to decrease.
On the other hand, when SiO ₂ / TiO ₂ exceeds 21,000, the antifouling effect based on the photocatalytic action of the titania-based coating is weakened, so that the time required for the decomposition of the dirt tends to increase remarkably. Further, when the titanium-containing sol is used as a raw material for the ink receiving layer forming coating solution, the decoloring effect based on the photocatalytic action of the titania fine particles is weakened, and therefore the time required for decoloring of printing or printing is reduced. There is a tendency to increase significantly.

If the weight ratio of Si and Ti is in the above range, the fine particles (a) are the fine particles (a1) (the titania fine particles and the non-porous silica fine particles) or the fine particles (a2) (the titanate compound surface). Any of the modified non-porous silica fine particles) exhibits a good antifouling effect and a decoloring effect. However, if the fine particles (a) are the fine particles (a1), SiO ₂ / TiO _2. = 8 to 16,000 is preferable, and when the fine particles (a) are the fine particles (a2), SiO ₂ / TiO ₂ = 500 to 20,000 is preferable. From the standpoint that excellent antifouling and decoloring effects tend to be exhibited even with a small amount of Ti, the fine particles (a2) (the surface is modified with the titanate compound as the fine particles (a)). Non-porous silica fine particles) are preferably used.

  If necessary, the titanium-containing silica sol (a1s) containing the titania fine particles and the nonporous silica fine particles (a1) and the dispersion medium (b), and the surface-modified nonporous silica fine particles (a2) and the above A titanium-containing silica sol (a2s) containing the dispersion medium (b) may be mixed and used.

  The solid content concentration of the titanium-containing silica sol of the present invention is usually 1 to 30% by weight, but is not limited to this range, and is mixed with a binder component described later or the film thickness of an antifouling coating described later. It is desirable to adjust appropriately for the purpose of preparation.

  The titanium-containing silica sol of the present invention includes antimony fine particles, silica fine particles other than the non-porous silica fine particles, alumina fine particles, zirconia fine particles, calcium carbonate, clay, titanium oxide, zinc oxide, talc and the like as necessary. Fine particles; ink set agent, ultraviolet absorber, surfactant, antibacterial agent and the like may be included. Among these particles that can be contained in the titanium-containing silica sol of the present invention, in particular, inorganic fine particles that can have a peroxide structure and inorganic fine particles that release active oxygen when irradiated with ultraviolet rays are preferable in terms of soil decomposition performance.

[Composition for forming an antifouling film]
When the titanium-containing silica sol of the present invention is used, a composition for forming an antifouling film comprising the titanium-containing silica sol and the binder (c) can be produced.

  As this binder (c), an organic resin, celluloses, starch, or an inorganic compound can be used. Examples of the organic resin include styrene / maleic anhydride copolymer, styrene / alkyl acrylate copolymer, polyvinyl alcohol, ethylene / vinyl alcohol copolymer containing silanol group, polyvinyl pyrrolidone, ethylene / vinyl acetate copolymer. , Methyl ethyl cellulose, sodium polyacrylate, polyethylene polyamine, polyester, polyacrylamide, vinylpyrrolidone / vinyl acetate copolymer, cation-modified polyurethane resin, tertiary nitrogen-containing acrylic resin (see JP-A-62-148292) Examples of the celluloses include biocellulose; Examples of the inorganic compounds include sodium silicate, potassium silicate, lithium silicate, etc., or a mixture thereof, a hydrolyzate of organic silicon, and an organically modified inorganic compound. Such as ceramics and the like. These may be used alone or in combination of two or more.

  The titanium-containing silica sol and the binder (c) may be mixed in a solid content weight ratio of titanium-containing silica sol: binder = 95 to 40: 5 to 60 (the sum of both being 100). preferable.

[Anti-fouling coating]
After forming a layer on the substrate using the antifouling film forming composition, the antifouling film can be formed by drying the layer. When the antifouling film-forming composition is applied onto a substrate to form an antifouling film, the coating method is not particularly limited, and an appropriate coating method is adopted depending on the type of the substrate. It is done. Specifically, conventionally known methods such as a spray method, a brush coating method, a dipping method, a roll coater method, a blade coater method, a bar coater method, and a curtain coater method can be employed. As a drying method, a conventionally known method such as air drying can be employed.

  The antifouling coating can be formed on a wide range of substrates, including substrates with coatings formed from various paints, metals, wood, ceramics, plastics, paper such as pulp paper and synthetic paper , OHP sheets, resin films, fabrics, metal foils, glasses, or composites thereof.

The coating amount of the antifouling film forming composition may be appropriately determined according to the substrate and application. For example, if the substrate is a printing paper or an OHP sheet, it is usually 1 to 50 g / in solid weight. m ²
, Preferably ² to 30 g / m ² .

[Anti-fouling method]
Contamination prevention of the base material using the antifouling coating is carried out by applying an antifouling coating such as an ultraviolet ray on the antifouling coating when a dirt substance as an organic compound adheres to the antifouling coating and dullness or coloring occurs. This is accomplished by decomposing and removing soiling substances by irradiating with light or contacting with acid gas or ozone.

Among these methods, ultraviolet irradiation is preferable. Examples of the light source for ultraviolet irradiation include a mercury lamp, a metal halide lamp, a gallium lamp, a mercury xenon lamp, and a flash lamp. In addition, there is an effect by irradiation with sunlight. For the irradiation equipment such as ultraviolet rays, either scanning type or non-scanning type may be selected according to the irradiation area, irradiation dose, etc., and the irradiation condition is the irradiation width according to the irradiation energy required to decompose the dirt. You can decide. Examples of the acidic gas to be contacted include SO ₂ gas and CO ₂ gas.

  When the antifouling film is formed on the surface of paper such as copy paper or an OHP sheet, the antifouling film can also be used as an ink receiving layer when printing with an ink jet printer or the like. In this case, not only can dirt substances adhering to paper etc. be decomposed by UV irradiation or contact with acidic gas or ozone, but depending on the type of printing ink, ink taken as a print or print in the ink receiving layer may It can be decomposed by irradiation or contact with acid gas or ozone, and can contribute to the recycling of paper. In addition, the coloring by printing and printing can be reduced by adjusting the type of printing ink, the conditions of ultraviolet irradiation, or contact with acid gas or ozone.

Furthermore, when the antifouling coating is applied to the ship bottom or the like, the adhesion of green algae such as blue seaweed to the ship bottom or the like is suppressed without taking any special measures.
[Coating liquid for forming ink receiving layer and method for producing the same]
The coating liquid for forming an ink receiving layer of the present invention contains the titanium-containing sol of the present invention and a binder (c ′).

In the present specification, the dispersion medium (b) contained in the ink-receiving layer-forming coating liquid is also referred to as “solvent (B) composed of water and / or an organic solvent”.
The coating liquid for forming the ink receiving layer of the present invention is preferably
(A): 100 parts by weight of a mixture of titania fine particles and nonporous silica fine particles (a1), or nonporous silica fine particles (a2) obtained by surface modification with a titanate compound, and the binder (c ′) 5 to 150 parts by weight,
The weight (W _B ) of the dispersion medium (b) (solvent (B) comprising water and / or organic solvent), the mixture (a) and the binder (c ′) ((a) and (c ′) And the total weight (W _A + W _{C ′} ) of W _B : (W _A + W _{C ′} ) = 99.
9 to 50: 0.1 to 50 (provided that the total is 100),
The content of Si and Ti constituting the mixture (a1) or the non-porous silica fine particles (a2) obtained by surface modification with the titanate compound is 5 to 21, when converted to a SiO ₂ / TiO ₂ weight ratio. In the range of 000.

(C ′) Binder:
Examples of the binder (c ′) used in the ink receiving layer forming coating liquid of the present invention include hydrophilic polymers such as polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone and modified polyvinyl pyrrolidone, and celluloses such as ethyl cellulose. it can. These may be used alone or in combination of two or more.

  The amount of the binder (c ′) used varies depending on the type of the binder, but the above-mentioned (a) (a mixture of titania fine particles and non-porous silica fine particles (a1), or non-modified with a titanate compound is used. 5 to 150 parts by weight, preferably 10 to 70 parts by weight, per 100 parts by weight of the porous silica fine particles (a2)). When the amount of the binder (c ′) is less than 5 parts by weight, the adhesive force between the ink receiving layer and the substrate such as a sheet is insufficient, and the ink receiving layer is easily peeled off, and the strength of the ink receiving layer becomes insufficient. If the amount exceeds 150 parts by weight, the amount of ink received may be reduced or the water resistance may be reduced.

  The coating liquid for forming an ink receiving layer according to the present invention improves the adhesion between the ink receiving layer and a substrate such as a sheet, improves the strength and weather resistance of the ink receiving layer, For the purpose of adjusting the pore structure, an antioxidant, organic polymers such as celluloses, biofibers, inorganic polymers, inorganic fine particles, and the like may be contained.

<Method for producing coating liquid for forming ink receiving layer>
The method for producing the coating liquid for forming the ink receiving layer containing the titania fine particles and the non-porous silica fine particles (a1) is not particularly limited, and the mixture (a1) of the titania fine particles and the non-porous silica fine particles and the binder (c ′) And a solvent (B) composed of water and / or an organic solvent can be mixed. From a practical viewpoint, the titania fine particles and non-porous silica fine particles (a1) are dispersed in a dispersion medium. The titanium-containing silica sol (a1s), the binder (c ′) and the solvent (B) composed of water and / or an organic solvent are preferably mixed.

  Moreover, the manufacturing method of the coating liquid for ink-receiving layer formation containing the non-porous silica fine particles (a2) whose surface is modified with a titanate compound is not particularly limited, and the surface-modified non-porous silica fine particles ( a2), a binder (c ′) and a solvent (B) composed of water and / or an organic solvent can be mixed. From a practical viewpoint, the surface-modified non-porous silica fine particles (a2) A method of mixing a titanium-containing silica sol (a2s) dispersed in a dispersion medium, a binder (c ′) and a solvent (B) composed of water and / or an organic solvent is preferable.

  When the sufficient amount of the dispersion medium (b) to ensure fluidity as the ink receiving layer forming coating liquid is contained in the titanium-containing silica sol (a1s) or the titanium-containing silica sol (a2s). It is not necessary to add a solvent (B) consisting of water and / or an organic solvent.

For the mixing operation of the above components, devices such as a homogenizer, a homomixer, a roller disperser, a three roll mill, a powerful stirrer, an ultrasonic wave, and a sand mill are usually used.
[Base material with ink receiving layer]
The base material with an ink receiving layer according to the present invention comprises a base material and an ink receiving layer formed on the surface of the base material. This base material with an ink receiving layer is used as a recording base material (that is, a base material for recording with an ink receiving layer). As a substrate with an ink receiving layer, a sheet-like substrate (hereinafter referred to as “substrate sheet”)
Also called. ) And an ink receiving layer formed on the surface of the substrate is preferable. “Recording” refers to drawing and holding characters, images, etc. on a substrate by means of printing such as an ink jet method.

  Although it does not specifically limit as said base material sheet, Resin-made film sheets, such as PET and PVC, plain paper, various papers, a steel plate, cloth, etc. are used. These base materials may be used after primer treatment in advance.

  The titania fine particles and the non-porous silica fine particles (a1) (also simply referred to as “fine particles (a1)”) or the surface-modified non-porous silica fine particles (a2) (also simply referred to as “fine particles (a2)”). May be primary particles or secondary particles, and primary particles and secondary particles may be mixed. The secondary particles are particles in which the primary particles are aggregated to such an extent that they are not easily monodispersed into the primary particles in the coating solution. Note that the primary particles may include those in which the secondary particles are loosened to be primary particles.

As a method for forming the ink receiving layer on the substrate, a known method can be adopted, and a preferred method may be adopted depending on the type of the substrate.
Specifically, the base material with an ink receiving layer was coated on the surface of the base material by a spray method, a roll coater method, a blade coater method, a bar coater method, a curtain coater method, or the like. Thereafter, it can be formed by drying.

  The substrate with an ink receiving layer is coated with an ink receiving layer forming coating solution in which the fine particles (a1) or the fine particles (a2) are dispersed in water and / or an organic solvent, and dried. After that, the cationic hydrated metal compound can be formed by supporting it on the surface of the fine particles (a1) or the fine particles (a2). For example, a cationic hydrated metal compound solution with alkali added as needed is applied onto a substrate such as a sheet by spraying, roll coater, blade coater, bar coater, or curtain coater. Then, by drying, the cationic hydrated metal compound can be supported on the surface of the fine particles (a1) or the fine particles (a2).

Examples of the cationic hydrated metal compound include Al ₂ (OH) ₅ Cl, ZrOCl _{2 and the} like. The weight of the cationic hydrated metal compound and oxide particles (cationic hydrated metal compound / (the fine particles (a1) or the fine particles (a2))) is 0.005 to 0.2. It is preferable that it exists in the range. In this case, if the ratio of the cationic hydrated metal compound to (the fine particles (a1) or the fine particles (a2)) is within the above range, the concentration of the cationic hydrated metal compound solution is particularly limited. There is no.

Application and drying can be repeated.
The ink receiving layer thus formed generally has at least a pore diameter in the range of 3.4 to 2,000 nm regardless of whether dye-based ink or pigment-based ink is used. It is preferable to have pores. Further, among these pores, the pore volume of pores having a pore diameter of 3.4 to 30 nm is in the range of 0.2 to 3.0 ml / g, or the pore diameter is 30 to 2,000 nm. It is preferable that the pore volume of a certain pore is in the range of 0.1 to 2.5 ml / g.

  If the pore volume of the pore having a pore diameter of 3.4 to 30 nm is less than 0.2 ml / g, the ink absorption capacity is small, bleeding occurs, and a clear and highly accurate image may not be obtained. is there. On the other hand, if the pore volume of the pores of 3.4 to 30 nm is larger than 3.0 ml / g, the fixing property of the dye may be lowered and the strength of the ink receiving layer may be lowered.

Further, when the pore volume of pores having a pore diameter of 30 to 2,000 nm is less than 2.5 ml / g, the pigment-based ink cannot be sufficiently absorbed, and pigment particles remain on the surface of the receiving layer. In some cases, the ink-receptive layer-attached substrate may lose color due to peeling due to abrasion. In addition, when the pore volume of pores having a pore diameter of 30 to 2,000 nm is larger than 2.5 ml / g, the fixability of the pigment particles is reduced, or after printing, most of the pigment particles are in the ink receiving layer. Characters and images that accumulate in the lower part (near the substrate surface) and are drawn on the substrate with an ink receiving layer may lack clarity.

  The thickness of the ink receiving layer formed on the substrate can be arbitrarily set depending on the thickness of the substrate, the use of the printed material, the type of printing ink, etc., but is usually in the range of 0.5 to 100 μm. It is desirable to be in When the thickness of the ink receiving layer is less than 0.5 μm, the ink absorption capacity is insufficient and bleeding occurs, and when the amount of ink used is reduced, the color may be lowered. An ink-receiving layer thicker than 100 μm is difficult to obtain by a single coating, and performing multiple coatings is problematic in terms of economy, and cracks when applied and dried May occur or peel off. In addition, the decoloring property may be deteriorated.

The pore volume per unit weight of the ink receiving layer is a value measured by the mercury intrusion method as follows:
(1) About 0.2 to 0.3 g of a sheet with an ink receiving layer whose weight ratio between the sheet and the ink receiving layer was determined in advance was inserted into a measuring cell (0.5 cc volume), and AUTOSCAN-60 PORPSIMETER manufactured by QUANTA CHROME , The mercury contact angle is 130 °, the mercury surface tension is 473 dyn / cm ² , the measurement range is set to “high pressure”, and the pore distribution is measured.
(2) Next, from the measured pore distribution, the pore volume of the pore having a pore diameter of 3.4 to 30 nm and the pore volume of the pore having a pore diameter of 30 to 2,000 nm are obtained and measured. The pore volume per 1 g of the receiving layer is determined from the weight of the receiving layer in the sheet.

Erasing method;
After printing or printing on the substrate with an ink-receiving layer of the present invention by means of printing such as ink jet printing, the printing or printing is erased by irradiation with ultraviolet rays or contact with acid gas or ozone. Can color. By doing so, the substrate can be regenerated and used again.

Among these methods, ultraviolet irradiation is preferable. Examples of the light source for ultraviolet irradiation include a mercury lamp, a metal halide lamp, a gallium lamp, a mercury xenon lamp, and a flash lamp. In addition, there is an effect by irradiation with sunlight. As an irradiation device such as ultraviolet rays, either scanning type or non-scanning type may be selected according to the irradiation area, irradiation dose, etc., and the irradiation condition depends on the irradiation energy required to decompose the print or print. What is necessary is just to decide irradiation width. Examples of the acidic gas to be contacted include SO ₂ gas and CO ₂ gas.

The degree of the decoloring effect can be appropriately adjusted depending on the time to be used for the decoloring means (ultraviolet irradiation, contact with acid gas or ozone).
The ink used for the printing or printing is not particularly limited as long as it is an ink that can provide a decoloring effect by the decoloring means, but can also be used as an ink containing a dye or an ink containing a pigment.

The ink containing a dye preferably includes an ink containing the following dye;
C. I. Solvent Black 27, C.I. I. Solvent Black 28, C.I. I. Solvent Black 22, C.I. I. Solvent Black 29, C.I. I. Solvent Red 83 1, C.I. I. Solvent Red 125, C.I. I. SolventRed132, C.I. I. Solvent Blue 47, C.I. I. So
lvent Blue48, C.I. I. Solvent Blue 70, C.I. I. Solvent Yellow 88, C.I. I. Solvent Yellow 89, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I. I. Basic Red
1, C.I. I. Basic Red8, C.I. I. Basic Black2, Basic B
lue5, Basic Blue7, Basic Violet1, Basic Viol
et10, Basic Orange 22, Basic Red 1: 1, Basic Ye
basic dyes such as llow1, Basic Yellow2, and Basic Yellow3.

In addition, natural pigments produced by microorganisms that exhibit decoloring properties by ultraviolet rays can also be used. Examples of such natural pigments include red potato pigments.
Examples of solvents for these dyes include ketones such as methyl ethyl ketone, acetone and cyclohexanone; alcohols such as methanol, ethanol and isopropanol; ethers such as cellosolve and butyrocellosolve; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, Alkylene glycols such as hexylene glycol; alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol methyl ether, triethylene glycol monomethyl ether, diethylene glycol ethyl ether, triethylene glycol monoethyl ether; glycerin, polyethylene glycol, polypropylene Polyalkylene glycols such as glycol; N-methyl-2-pyro Don, 1,3-dimethyl-2-imidazolidinone nitrogen-containing heterocyclic ketones such as; ion-exchanged water and the like, which can be used alone or in combination of two or more.

  As the ink containing a pigment, an ink in which a pigment is dispersed in an aqueous medium using a dispersant is used. As the dispersant, a surfactant or the like is widely used. As the pigment, an organic pigment or an inorganic pigment can be used.

  Organic pigments include azo pigments (for example, azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments). Thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black and the like.

  Examples of the inorganic pigment include carbon black produced by a known method such as a contact method, a furnace method, and a thermal method in addition to titanium oxide and iron oxide, more specifically, furnace black, lamp black, acetylene black, And carbon black such as channel black (C.I. Pigment Black 7).

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

<Evaluation method>
Specific surface area;
The specific surface area of the silica fine particles was determined by the nitrogen adsorption method using a specific surface area measuring device (“Multisorb 12” manufactured by Yuasa Ionics) for a sample obtained by drying silica sol with a freeze dryer and then drying at 110 ° C. for 20 hours. (BET method).

Average particle size;
The average particle size of the silica fine particles is determined by a particle size distribution measuring device (Particle Sizing).
Measurement was performed by a dynamic light scattering method using “NICOMP MODEL 380” manufactured by Systems, Inc.

Surface charge amount;
The surface charge amount of the silica fine particles was determined by using a streaming potential measuring device (MUTEK: PCD02) to disperse pure water of silica-alumina modified fine particles having a concentration of 1% by weight as an oxide (SiO ₂ + MO _x ). The body was prepared, poured into a measuring vessel and measured by titrating with a polymer having a charge opposite to the particle charge. Negatively charged silica fine particles were titrated using 0.001N poly-DADMAC (cationic polymer electrolyte) as a polymer standard solution.

Composition analysis;
The contents of Al and Na that may be contained in the silica sol containing Ti, Si, and titanate were measured by the following method.
[1] Ti, Al content (converted to TiO ₂ , Al ₂ O ₃ content)
After the pretreatment shown in 1) to 3) below, the measurement was performed using an ICP emission analyzer (Seiko Instruments SPS1200A type).

1) Collect about 5 g of titanate-containing silica sol in a platinum dish.
2) Dry on a sand bath and bake in an electric furnace at 1000 ° C. for about 1 minute.
3) Add 2 ml of sulfuric acid (1 + 1) and 10 ml of hydrofluoric acid, heat until a white smoke of sulfuric acid appears on the sand bath, and dilute to 100 ml with distilled water.
[2] Na content (converted to Na ₂ O content)
After the same pretreatment as [1] above, the measurement was performed using an atomic absorption photometer (Hitachi Z-5300 type).
[3] Si content (converted to SiO ₂ content)
The weight (solid content weight) after heating the titanate-containing silica sol at 1000 ° C. for 1 hour was measured. In the same manner as in the above [1] and [2], TiO ₂ in this solid content,
The total content of Al ₂ O ₃ and Na ₂ O was determined, and this value was subtracted from the weight of the entire solid content to obtain the content of SiO ₂ .

[Preparation of silica sol]
Silica sol (1);
No. 3 water glass was subjected to cation exchange and diluted with pure water to prepare silica sol (1) having a solid content concentration of 12% by weight and a pH of 3.

Silica sol (2);
Silica sol (product name: Cataloid SI-350) manufactured by Catalyst Kasei Kogyo Co., Ltd. is diluted with pure water and subjected to cation exchange to obtain a silica sol having a solid content concentration of 12% by weight and a pH of 3 (2) Was prepared.

Silica sol (3);
A silica sol (3) having a solid content concentration of 12% by weight and a pH of 3 in the same manner as the silica sol (2) except that a silica sol (product name: Cataloid SI-80P) manufactured by Catalyst Chemical Industry Co., Ltd. was used. Was prepared.

Silica sol (4);
A silica sol (4) having a solid content concentration of 12% by weight and a pH of 3 in the same manner as the silica sol (2) except that a silica sol (product name: Spherica slurry 120) manufactured by Catalyst Kasei Kogyo Co., Ltd. was used. Was prepared.

Silica sol (5);
A silica sol (5) having a solid content concentration of 12% by weight and a pH of 3 was prepared in the same manner as the silica sol (2) except that a silica sol (product name: Cataloid SN) manufactured by Catalyst Chemical Industry Co., Ltd. was used. did.

Silica sol (6);
A silica sol (6) having a solid content concentration of 12% by weight and a pH of 3 in the same manner as the silica sol (2) except that a silica sol (product name: Spherica Slurry 160P) manufactured by Catalyst Chemical Industry Co., Ltd. was used. Was prepared.

Silica sol (7);
A silica sol (7) having a solid content concentration of 12% by weight and a pH of 3 in the same manner as the silica sol (2) except that a silica sol (product name: Cataloid SI-45P) manufactured by Catalyst Chemical Industry Co., Ltd. was used. Was prepared.

[Preparation of titania-containing silica sol containing titania fine particles and non-porous silica fine particles and a dispersion medium]
[Example 1-1]
As shown in Table 2, 300 g of silica sol (2) was mixed with a titania sol having a solid content concentration of 10% by weight, an average particle diameter of titania of 10 nm, a titania crystal type of anatase type, and a dispersion medium of isopropyl alcohol, Si and Ti Was added so that the weight ratio (in terms of SiO ₂ / TiO ₂ ) was 10 (that is, 36 g of the titania sol was added) and mixed by stirring to prepare a titanium-containing silica sol (B).

  Next, the titanium-containing silica sol (B) and the cellulose binder (ethyl cellulose aqueous solution, solid content concentration 5% by weight) were mixed so that the weight ratio of the solid content was titanium-containing silica sol: cellulose binder = 75: 25, An antifouling film-forming composition was prepared.

[Examples 1-2 to 1-6, Comparative Examples 1-1 to 1-6]
In the same manner as in Example 1-1, titanium-containing silica sols (A) and (C) to (L) were prepared using the silica sol and titania sol shown in Table 2.

  Next, in the same manner as in Example 1-1, each titanium-containing silica sol (A), (C) to (L) and a cellulose binder (ethyl cellulose aqueous solution, solid content concentration 5% by weight) were mixed in a weight ratio of the solid content. Were mixed so that titanium-containing silica sol: cellulose binder = 75: 25, respectively, to prepare a composition for forming an antifouling film.

[Preparation of titania-containing silica sol containing non-porous silica fine particles surface-modified with titanate compound and dispersion medium]
[Example 2-1]
As shown in Table 3, the titanate compound [Product name: Preneact (registered trademark) KR-44, manufactured by Ajinomoto Co., Inc., compound name: isopropyltri (N-aminoethyl-aminoethyl) titanate] was added to 300 g of silica sol (2). Titanium-containing silica sol (b) was prepared by adding 0.030 g over 1 minute and then stirring and mixing at room temperature for 2 hours. In the obtained titanium-containing silica sol, the weight ratio of Si to Ti (in terms of SiO ₂ / TiO ₂ ) was 19,633.

Next, the titanium-containing silica sol (b) and the cellulose binder (ethylcellulose aqueous solution, solid content concentration 5% by weight) were mixed so that the weight ratio of the solid content was titanium-containing silica sol: cellulose binder = 75: 25. An antifouling film-forming composition was prepared.

[Examples 2-2 to 2-7, Comparative Examples 2-1 to 2-6]
In the same manner as in Example 2-1, using the silica sol shown in Table 3 and the titanate compound [product name: Preneact (registered trademark) KR-44], titanium-containing silica sol (a), (c) -(L) were prepared respectively.

  Subsequently, in the same manner as in Example 2-1, each titanium-containing silica sol (a), (c) to (l) and a cellulose binder (ethyl cellulose aqueous solution, solid content concentration 5% by weight) were mixed in a weight ratio of the solid content. Were mixed so that titanium-containing silica sol: cellulose binder = 75: 25, respectively, to prepare a composition for forming an antifouling film.

Underwater organism adhesion prevention test:
The antifouling film-forming compositions prepared in Examples 1-1 to 1-6 and Examples 2-1 to 2-7 were each dip-coated on a polyethylene mesh material for 10 minutes and air-dried. In addition, one type of antifouling film forming composition was applied to each net member. The coating amount of the composition was 1 part by weight with respect to 100 parts by weight of the netting material after drying. These mesh materials and mesh materials not coated with the antifouling film-forming composition were immersed in a constant temperature water bath (30 ° C.), left in an environment exposed to natural light for 3 months, and then pulled up from the water bath. In each net material to which the composition for forming an antifouling film was applied, the growth of sphagnum was remarkably suppressed as compared to the net material to which the composition for forming an antifouling film was not applied.

Dirt decomposition test:
Each antifouling film forming composition prepared as described above was applied to one side of plain paper in an amount of 5 g / m ² using a bar coder, and dried at 80 ° C. to form an antifouling film. A plain paper with an ink receiving layer was obtained. In addition, one type of antifouling film forming composition was applied to each plain paper.

  Plain paper with an ink-receiving layer having these antifouling coatings is placed in a dirt chamber test machine (volume 60 L), and 3 cigarettes (nicotine, tar content 16 mg / line) are smoked for 3 minutes on the surface of the paper. In a state where the smoke particles are adhered and dirty, a mini conveyor UV irradiation device (manufactured by Nihon Battery Co., Ltd.) is used to irradiate the paper with ultraviolet rays using a high-pressure mercury lamp and measure the time until the stain is decomposed. . The results are shown in Tables 2 and 3.

  Further, the inside of the dirt chamber test machine was filled with ozone gas, and the paper in which the smoke particles adhered and became dirty was placed there, and the time until the dirt was decomposed was measured. The results are shown in Tables 2 and 3.

  In addition, the time until the stain is decomposed is compared with the color of plain paper once smudged on the surface of the paper due to soot, and the antifouling coating composition. The color (white) of plain paper with an ink-receiving layer prepared for the purpose was compared visually to determine the time until the same color.

[Preparation of coating solution for forming ink receiving layer]
The titanium-containing silica sol 100 g prepared in Example 1-1 and the cellulose binder (ethyl cellulose aqueous solution, solid content concentration 5% by weight) were mixed so that the weight ratio of the solid content was titanium-containing silica sol: cellulose binder = 75: 25. By mixing, a coating solution for forming an ink receiving layer was prepared.

  Each of Examples 1-2 to 1-7 and Comparative Examples 1-1 to 1-6, Examples 2-1 to 2-7, Comparative Examples 2-1 to 2-6, and Examples 3-1 For each of the titanium-containing silica sols, a coating liquid for forming an ink receiving layer was prepared in the same manner as the titanium-containing silica sol prepared in Example 1-1.

Each ink-receiving layer-forming coating solution prepared as described above is applied to one side of plain paper in a quantity of 5 g / m ² using a bar coder, dried at 80 ° C., and plain paper with an ink-receiving layer. Got. One type of ink receiving layer forming coating solution was applied to each plain paper.

〔printing〕
A pattern W (2 cm) was applied to the obtained plain paper with an ink receiving layer by using an ink jet printer (manufactured by GRAPHTEC, Masterjet) using genuine pigment ink and dye ink.
The letter “W”, which is a size that fits all the squares on all sides and has a thickness of about 3 mm, was printed in black.

[Decolorization]
The printed plain paper with an ink-receiving layer is irradiated with ultraviolet light using a high-pressure mercury lamp on a paper surface by a mini conveyor type UV irradiation device (manufactured by Nippon Battery Co., Ltd.), and the time until the pattern W is decolored is determined. It was measured. The results are shown in Tables 2 and 3.

  Further, the inside of the dirt chamber test machine was filled with ozone gas, and the printed paper with the ink receiving layer was placed thereon, and the time until the pattern W was erased was measured. The results are shown in Tables 2 and 3.

  Note that the time until the color is erased is the color of the pattern W of the plain paper with the ink receiving layer erased by means such as ultraviolet irradiation after the pattern W is printed, The color (white) of plain paper with an ink receiving layer prepared for control using the coating solution was compared visually to determine the time until the same color was reached.

  When the titanium-containing silica sol of the present invention is used, an antifouling film having excellent antifouling performance can be formed on the surface of various substrates, and an ink receiving layer having excellent decoloring properties can be formed. . Therefore, the titanium-containing silica sol of the present invention is used as a raw material for a top coat of a ship bottom paint, a paint for a fish net, or a surface treatment agent such as a wall material, a ceiling material, a floor material or paper, or a coating liquid for forming an ink receiving layer. be able to.

Claims (13)

(A) the following fine particles (a1) or fine particles (a2);
(A1) Titania fine particles having an average particle diameter of 2 to 50 nm and nonporous silica having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g Fine particles,
(A2) The surface of the nonporous silica fine particles having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g is surface-modified with a titanate compound. Non-porous silica fine particles,
(B) containing a dispersion medium,
The content of Si and Ti constituting the titania fine particles and the non-porous silica fine particles (a1) or the non-porous silica fine particles (a2) obtained by surface modification with the titanate compound is in a SiO ₂ / TiO ₂ weight ratio. A titanium-containing silica sol characterized by being in the range of 5 to 21,000 in terms of conversion. The titanium-containing silica sol according to claim 1, wherein the titanate compound is represented by any one of the following general formulas (1) to (3):
R ¹¹ _n TiR ¹² _4-n (1)
[Where n is an integer of 1 to 4.
R ¹¹ is an alkoxy group having 1 to 6 carbon atoms, and when n = 2 or 3, two R ¹¹ 's may combine to form a ring structure represented by the following general formula (1a). Furthermore, two hydrogen atoms bonded to one of the carbon atoms adjacent to the oxygen atom in the general formula (1a) are substituted with an oxygen atom to form a ring structure represented by the following general formula (1b). May be.
R ¹² is a hydrocarbon group having 1 to 5 carbon atoms or an organic group represented by the following general formula (1c), (1d), (1e), (1f), (1g) or (1h).

(However, x is an integer of 1-7.)

(However, y is an integer of 1-7.)

(However, p is an integer of 4 to 30.)

(However, q is an integer of 4 to 30.)

(However, q ′ is an integer of 4 to 30.)

(However, r and r ′ are each an integer of 1 or more, and r + r ′ is 4 to 30.)

(However, s is an integer of 1-30.)

(However, t and t ′ are each an integer of 1 to 30.)]
R ²¹ TiR ²² R ²³ ₂ (2)
[Wherein R ²¹ is an alkoxy group having 1 to 4 carbon atoms, R ²² is an organic group represented by the following general formula (2a), and R ²³ is an organic group represented by the following general formula (2b). It is a group.

(However, u is an integer of 4 to 30.)

(However, R ′ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)]
R ³¹ ₄ Ti · [P (OC _2w H _{2w + 1} ) ₂ (OH)] ₂ (3)
[Wherein R ³¹ is an alkoxy group having 1 to 20 carbon atoms,
Some of the hydrogen atoms in the alkoxy group have 4 to 12 carbon atoms and may be substituted with an organic group having at least one of an ether bond and a double bond.
w is an integer of 4-20. ].   3. The titanium-containing silica sol according to claim 1, wherein a surface charge amount of the non-porous silica fine particles is in a range of 10 to 150 μeq per 1 g of the fine particles.   The titania sol containing the titania fine particles and the dispersion medium (b) and the silica sol containing the non-porous silica fine particles and the dispersion medium (b) are mixed. The manufacturing method of the titanium containing silica sol containing the said microparticles | fine-particles (a1) in any one.   A titanate compound is added to a silica sol containing the non-porous silica fine particles and a dispersion medium (b), and the fine particles (a2) according to any one of claims 1 to 3 are contained. A method for producing a titanium-containing silica sol.   A composition for forming an antifouling film, wherein a binder (c) selected from organic resins, celluloses, starches and inorganic compounds is dispersed in the titanium-containing silica sol according to any one of claims 1 to 3.   A coating liquid for forming an ink receiving layer, wherein a binder (c ′) selected from a hydrophilic polymer and celluloses is dispersed in the titanium-containing silica sol according to claim 1. 100 parts by weight of the fine particles (a1) or the fine particles (a2) and 5 to 150 parts by weight of the binder (c ′),
The weight (W _B ) of the dispersion medium (b), the fine particles (a1) or the fine particles (a2),
And the ratio to the total weight (W _A + W _{C ′} ) of the binder (c ′) is W _B : (W _A + W _{C ′}
) = 99.9-50: 0.1-50 (where the total is 100),
The content of Si and Ti constituting the fine particles (a1) or the fine particles (a2) is in the range of 5 to 21,000 when converted to a SiO ₂ / TiO ₂ weight ratio. The coating liquid for ink receiving layer formation as described. A titanium-containing silica sol (a1s) in which the titania fine particles and the non-porous silica fine particles (a1) are dispersed in the dispersion medium (b);
The binder (c ′);
The method for producing a coating liquid for forming an ink receiving layer according to claim 7 or 8, wherein the dispersion medium (b) is further mixed as necessary. A titanium-containing silica sol (a2s) in which the nonporous silica fine particles (a2) obtained by surface modification with the titanate compound are dispersed in the dispersion medium (b);
The binder (c ′);
The method for producing a coating liquid for forming an ink receiving layer according to claim 7 or 8, wherein the dispersion medium (b) is further mixed as necessary. On the substrate surface,
(A1) Titania fine particles having an average particle diameter of 2 to 50 nm and nonporous silica having an average particle diameter of 5 to 100 nm and a specific surface area determined by the BET method of 30 m ² / g or more and less than 550 m ² / g Fine particles, or (a2) The average particle diameter is 5 to 100 nm, and the specific surface area determined by the BET method is 30 m ^2.
Ink receiving layer comprising non-porous silica fine particles formed by surface-modifying the surface of non-porous silica fine particles having a particle size of not less than / g and less than 550 m ² / g with a titanate compound. Layered substrate.   The method for producing a substrate with an ink receiving layer according to claim 11, wherein the coating liquid for forming an ink receiving layer according to claim 7 or 8 is applied to the surface of the substrate and then dried.   Printing is performed using ink on the substrate with an ink-receiving layer according to claim 11 to form a print or print, and then the print or print is decolored by contact with ultraviolet light, acid gas or ozone. A method for regenerating a base material characterized by comprising: