JP6804857B2 - Titanium compounds and methods for producing them, titanium-based compositions, resin compositions, and titanium-based solids. - Google Patents

Description

The present invention relates to titanium compounds and methods for producing them, titanium-based compositions, resin compositions, and titanium-based solids.

Titania (titanium oxide) has photocatalytic performance by ultraviolet rays and is known as a chemically stable material. Due to its photocatalytic performance, titania is applied to various applications because, for example, it exhibits superhydrophilicization and decomposition functions of organic substances, and can decompose water to generate hydrogen and oxygen. .. In addition, titanium has excellent UV absorption and a high refractive index (for example, anatase-type titania has a refractive index of 2.5 or more, and rutile-type titania has a refractive index of 2.7 or more). It is also used as a sunscreen by taking advantage of its light scattering property.

Since it is difficult to obtain a transparent coating film due to the light scattering effect of titania due to its high refractive index, various techniques have been proposed in recent years in order to form a coating film having higher transparency. For example, Patent Document 1 proposes a technique in which nanoparticles treated with a surface treatment agent are dispersed in a resin or the like to enhance the transparency of the resin coating film or the like and increase the refractive index.

Japanese Unexamined Patent Publication No. 2006-273709

However, as the particle size becomes smaller like the nanoparticles, the secondary agglutination of the nanoparticles is more likely to occur in the resin, and the secondary agglutination causes light scattering, which may make it difficult to obtain high transparency. .. Further, for example, when the surface of the titania particles is surface-modified as in the technique disclosed in Patent Document 1, secondary aggregation is certainly suppressed, but the material for surface modification has a lower refractive index than titania. Therefore, there is a problem of causing a decrease in the refractive index. From such a viewpoint, it has been desired to develop a titanium compound that can impart high refractive index and high transparency to various materials and can be prepared at low cost.

The present invention has been made in view of the above, and a titanium compound which can impart high refractive index and high transparency to various materials and can be prepared at low cost and a method for producing the same. The purpose is to provide. Furthermore, the present invention relates to a titanium-based composition and a resin composition containing the titanium compound, and a titanium-based solid obtained from the titanium compound.

As a result of intensive studies to achieve the above object, the present inventor has found that the above object can be achieved by introducing a specific skeletal structure into a titanium compound, and has completed the present invention.

That is, the present invention includes, for example, the subjects described in the following sections.
Item 1. The following general formulas (1) and (2)

(In formula (1), R ¹ is either an acetyl group or a group having a carbonyl group other than the acetyl group)
It has each structural unit represented by and
A titanium compound having 4 or more Ti atoms.
Item 2. The following general formulas (3) and (4)

In (Equation (3) and (4), R ² is either a group having an alkyl group, hydrogen, carbonyl groups other than acetyl group or an acetyl group, a plurality of R ² of formula (3) are the same or different even if well, equation (4) a plurality of ^{R 2} of the same or ^{R 2} and ^{R 2} of formula (4) may be the same or different, ^{R 1} and equation (3) of the formula (1) May be different)
Item 2. The titanium compound according to Item 1, further comprising at least one of the structural units represented by.
Item 3. Item 2. The titanium compound according to Item 2, wherein 50% or more of the total amount of all R ¹ and all R ² is at least one of the acetyl group and the group having the carbonyl group.
Item 4. The method for producing a titanium compound according to any one of Items 1 to 3 above.
The following general formula (5)

(In formula (5), R ³ is an alkyl group, and a plurality of R ³ in formula (5) may be the same or different, and n is an integer of 1 or more).
Production of a titanium compound comprising a step of reacting a titanium raw material represented by (R4) with R ^4- OH (R ⁴ is any of an alkyl group, an acetyl group or a group having a carbonyl group other than an acetyl group). Method.
Item 5. Item 4. The production method according to Item 4, wherein 0.8 molar equivalent or more of the R ^4- OH is reacted with R ^{3 of the} titanium raw material represented by the above formula (5).
Item 6. Item 4. The production method according to Item 4 or 5, wherein the reaction is carried out in a polar solvent having at least one of an OH group and a carbonyl group.
Item 7. The production method according to any one of Items 4 to 6, wherein the reaction is carried out by heat treatment at 50 ° C. or higher for 10 minutes or longer.
Item 8. R ⁴ is at least one of the radicals having a carbonyl group other than acetyl group and an acetyl group, wherein the boiling point of R ⁴ -OH is 200 ° C. or less, the production method according to any one of the above items 4 to 7 ..
Item 9. A titanium-based composition containing the titanium compound according to Item 1 or 2 above and a polar solvent having at least one of an OH group and a carbonyl group.
Item 10. A resin composition containing the titanium compound according to any one of Items 1 to 3 and a resin.
Item 11. Item 2. The resin composition according to Item 10, wherein the resin is an organic resin and has two or more reactive functional groups.
Item 12. Item 2. The resin composition according to Item 10 or 11, wherein the resin is at least one selected from the group consisting of an epoxy resin, an acrylic resin, and an epoxy acrylate resin.
Item 13. The resin composition according to any one of Items 10 to 12, wherein the resin has a refractive index of 1.60 or more and less than 2.0.
Item 14. Item 2. The resin composition according to any one of Items 10 to 13, wherein the resin contains at least one of a fluorene skeleton and a naphthalene skeleton.
Item 15. A titanium-based solid obtained by heating the titanium compound according to any one of the above items 1 to 3 to 50 ° C. or higher and containing the structural unit of the above formula (2).
Item 16. A titanium-based solid obtained by heating the resin composition according to any one of the above items 10 to 14 to 50 ° C. or higher and containing the structural unit of the above formula (2).
Item 17. Item 2. The titanium-based solid according to Item 15 or 16, which has a refractive index of 1.75 or more.
Item 18. The following general formula (6)

Item 2. The resin composition according to any one of Items 10 to 14, which has a structure represented by.

Since the titanium compound according to the present invention has a specific skeletal structure, it can impart high refractive index and high transparency to various materials.

The method for producing a titanium compound according to the present invention can produce the titanium compound easily and at low cost, and is suitable as a method for producing the titanium compound.

Since the titanium-based composition according to the present invention contains the titanium compound, it is suitable as a material for forming a coating film having a high refractive index and high transparency.

Since the resin composition according to the present invention contains the titanium compound, it is suitable as a material for forming a resin coating film having a high refractive index and high transparency.

Since the titanium-based solid according to the present invention is formed from the material containing the titanium compound, it has a high refractive index and high transparency.

It is a photograph which shows the appearance of the solution prepared in Example 2. It is a photograph which shows the state of having evaluated the transparency of the spin coat film formed from the solution prepared in Example 2.

Hereinafter, embodiments of the present invention will be described in detail.

<Titanium compound>
The titanium compound of this embodiment has the following general formulas (1) and (2).

(In formula (1), R ¹ is either an acetyl group or a group having a carbonyl group other than the acetyl group)
It has each structural unit represented by and
The number of Ti atoms is 4 or more.

When R ¹ is a group having a carbonyl group other than an acetyl group, such a group can be expressed as, for example, " ^Ra- CO-". Here, R ^a is exemplified by an aryl group is a cyclic alkyl group, carbon number 6 to 10 is a C3-10 alkyl group or a C number of 2 or more straight, also, any substituent May further have. Of course, the group having a carbonyl group other than the acetyl group is not limited to the above.

Specific examples of a group having a carbonyl group other than an acetyl group include a group obtained by removing a hydroxyl group (-OH group) from various carboxylic acids. Examples of this carboxylic acid include monofunctional carboxylic acids such as propionic acid; polyfunctional carboxylic acids such as malonic acid, succinic acid and oxalic acid; and hydroxycarboxylic acids having hydroxyl groups such as glycolic acid, lactic acid, tartaric acid and malic acid; Examples thereof include carboxylic acids anhydride such as acetic anhydride, succinic anhydride, and malonic anhydride.

In the titanium compound of the present embodiment, R ¹ in the formula (1) is an acetyl group or a group having a carbonyl group other than the acetyl group (for example, ^Ra- CO-). As a result, the terminal structure of the titanium compound becomes more stable, so that rapid hydrolysis is suppressed, so that the coating film formed by using the titanium compound is less likely to become cloudy, and it is easy to impart high transparency. Further, after the titanium compound is hydrolyzed, R ¹ in the formula (1) is unlikely to remain, so that a higher refractive index can be easily imparted. The more preferable R ¹ in the formula (1) is an acetyl group, and in this case, R ¹ is less likely to remain, and even if it remains, the refractive index is less likely to decrease.
From the same viewpoint, in the case of a group having a carbonyl group other than an acetyl group, a carbonyl group derived from a carboxylic acid having a low boiling point such as propionic acid or lactic acid, or a carbonyl group derived from a carboxylic acid such as oxalic acid which is easily decomposed. Is preferable.

As described above, since the titanium compound of the present embodiment has a specific structure, the progress of hydrolysis is appropriately controlled, so that the Ti-OR structure is unlikely to remain in the compound and the refractive index can be improved. ..

The titanium compound of this embodiment has the following general formulas (3) and (4).

(In formulas (3) and (4), R ² is any of an alkyl group, a hydrogen, an acetyl group, or a group having a carbonyl group other than an acetyl group, and a plurality of R ^{2 in the} formula (3) are the same or different. even if well, equation (4) a plurality of ^{R 2} of the same or ^{R 2} and ^{R 2} of formula (4) may be the same or different, ^{R 1} and equation (3) of the formula (1) May be different)
It is preferable to further have at least one of the structural units represented by.

When R ² is an alkyl group, for example, a linear or branched alkyl group having 2 to 18 carbon atoms or a cyclic alkyl group having 3 to 10 carbon atoms can be mentioned. The alkyl group may further have one or more substituents.

As the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n Examples thereof include a-octyl group, 2-ethylhexyl group, n-stearyl group, cyclohexyl group and decahydronaphthyl group. If the carbon number and branching are adjusted to an appropriate range, the hydrolysis rate tends to be in a desired range, the stability of the compound can be further improved, and the refractive index can be easily improved. From these viewpoints, the alkyl group is n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl. A group and a 2-ethylhexyl group are preferable, and an n-propyl group, an isopropyl group, an n-butyl group and a t-butyl group are more preferable.

If R ² is an alkyl group, the titanium compound of this embodiment has an alkoxide, if R ² is hydrogen, the titanium compound of this embodiment has a hydroxyl group, and if R ² is an acetyl group. The titanium compound of the present embodiment has an acetic acid ester, and if R ² is the above-mentioned " ^Ra- CO-", the titanium compound of the present embodiment has an ester structure other than the acetic acid ester.

When R ² is a group having a carbonyl group other than an acetyl group, the type thereof is the same as that of the group having a carbonyl group in the formula (1).

The titanium compound of the present embodiment may have a structure in which each structural unit represented by the above formulas (1) to (4) is randomly bonded.

The titanium compound of the present embodiment has 4 or more Ti atoms per molecule. In other words, the total amount of each structural unit represented by the above formulas (1) to (4) per molecule of the titanium compound of the present embodiment is 4 or more (that is, the titanium compound is a tetramer or more). .. When the number of Ti atoms per molecule is 4 or more, the terminal structure becomes more stable as compared with, for example, a titanium compound having 1 Ti atom number. Thus, hydrolysis of ^R 1 -O site and ^R 2 -O sites bound to Ti atom (e.g., hydrolysis reaction to ^{Ti-O-R 1} (alkyl group) → Ti-OH) and condensation (For example, a condensation reaction from 2Ti-OH to Ti-O-Ti) can be easily prevented from occurring suddenly. Therefore, the stability of the titanium compound is high under normal temperature (for example, 20 ° C.) or low temperature conditions of 100 ° C. or lower, white turbidity of the coating film formed by using the titanium compound is unlikely to occur, and a solution containing the titanium compound. It is easy to maintain a stable state for a long period of time. Furthermore, since the number of Ti atoms per molecule is 4 or more, the hydrolysis and condensation reactions of the titanium compound proceed slowly even when the titanium compound is heated to a predetermined temperature. used coating film formed has high transparency, moreover, the terminal structure in the titanium compound (R 1 ^O-group) is less likely to remain after the reaction. As a result, the structure of the titanium compound after the hydrolysis and condensation reaction becomes TiO ₂ or a structure similar thereto, and a coating film having a high refractive index is easily formed.

The number of Ti atoms per molecule of the titanium compound of the present embodiment is preferably 8 or more. The upper limit of the number of Ti atoms per molecule of the titanium compound is not particularly limited, but can be, for example, 100,000.

In the titanium compound of the present embodiment, the content ratio of each structural unit is not particularly limited as long as it contains the structural units of the formulas (1) and (2). For example, the content of the structural units of the formulas (1) and (2) is preferably 50% or more, more preferably 60% or more, based on the total mass of all the structural units constituting the titanium compound.

The titanium compound of the present embodiment can be imparted with transparency and a high refractive index by introducing the above-mentioned structure. Therefore, for example, if the titanium compound is used, a coating film having transparency and a high refractive index can be formed on a base material such as a silicon substrate.

Since the titanium compound of the present embodiment has the above structure, it has an excellent affinity with a resin, particularly an organic resin. Taking advantage of these characteristics, when used in combination with an organic material such as an organic resin as described later, it is easy to form a resin coating film having excellent transparency and a high refractive index, and the film thickness can be easily adjusted. It is possible to do. Further, the titanium compound of the present embodiment can be easily formed into a solid (for example, film-like) titanium material (titanium-based solid) by heat treatment. Since this titanium-based solid is formed of a material containing the above titanium compound, it has high transparency and a high refractive index.

From the above, the titanium compound of the present embodiment is suitable for applications of high refractive index materials, and is particularly suitable for applications in fields where transparency is required. The titanium compound of the present embodiment is suitable for hard coating applications of optical lenses, for example, which require high refractive index and refractive index controllability in accordance with hardness and transparency and high refractive index lens. Further, the titanium compound of the present embodiment is suitable, for example, for light extraction applications of LED lighting, which are required to improve light extraction efficiency due to transparency and high refractive index. Further, the titanium compound of the present embodiment can be used for high reflectance coating applications because the reflectance is increased by increasing the refractive index, for example.

In the titanium compound of the present embodiment, 50% or more of the total amount of all R ¹ and all R ² is at least one of the groups having an acetyl group and a carbonyl group (“ ^Ra −CO−”). Is preferable. In other words, in the titanium compound of the present embodiment, 50 mol% or more of the total number of moles of R ¹ and R ² is at least one of the groups having an acetyl group and a carbonyl group (“ ^Ra −CO−”). Is preferable. In this case, since the hydrolysis and condensation reactions of the titanium compound proceed more slowly, the transparency and refractive index of the coating film formed by using the titanium compound are particularly high, and the affinity with the resin is also further improved. To do. More preferably, 80 mol% or more of the total number of moles of R ¹ and R ² is at least one of the groups having an acetyl group and a carbonyl group (“ ^Ra −CO−”).

<Manufacturing method of titanium compound>
The method for producing the titanium compound is not particularly limited, but for example, the titanium compound can be produced by a production method including the following steps.

That is, the titanium compound has the following general formula (5).

(In formula (5), R ³ is an alkyl group, and a plurality of R ³ in formula (5) may be the same or different, and n is an integer of 1 or more).
It is produced by a production method comprising a step of reacting a titanium raw material represented by (R4) with R ^4- OH (R ⁴ is any of an alkyl group, an acetyl group or a group having a carbonyl group other than an acetyl group). obtain.

Through the above steps, the reaction between the titanium raw material represented by the formula (5) and R ^4- OH proceeds. By this reaction, all or a part of a plurality of R ³ of the titanium raw material is replaced with R ⁴ , and the above titanium compound is obtained. This reaction is, for example, a hydrolysis reaction and a condensation reaction. By the above reaction, the titanium raw material is polymerized to increase the molecular weight, and a titanium compound having a stable structure is produced.

The R ^3, for example, straight-chain or branched alkyl group or cyclic alkyl group having 3 to 10 carbon atoms, is 1 to 18 carbon atoms. The alkyl group may further have one or more substituents. As the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n Examples thereof include a-octyl group, 2-ethylhexyl group, n-stearyl group, cyclohexyl group and decahydronaphthyl group. If the carbon number and branching are adjusted to an appropriate range, the hydrolysis rate tends to be in a desired range, the stability of the compound can be further improved, and the refractive index can be easily improved. From these viewpoints, the alkyl group is n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl. A group and a 2-ethylhexyl group are preferable, and an n-propyl group, an isopropyl group, an n-butyl group and a t-butyl group are more preferable.

The titanium raw material is a titanium alkoxide when n in the formula (5) is 1, and a titanium alkoxide oligomer when n is 2 or more.

The value of n is preferably 2 to 40, and in this case, the obtained titanium compound can easily impart transparency and a high refractive index, and the production of the titanium compound becomes easier.

The above R ^4- OH is acetic acid when R ⁴ is an acetyl group.

Further, when R ⁴ is a group having a carbonyl group other than an acetyl group, the R ^4- OH is, for example, a carboxylic acid other than acetic acid. Specific examples of such carboxylic acids include monofunctional carboxylic acids such as propionic acid; polyfunctional carboxylic acids such as malonic acid, succinic acid and oxalic acid; and glycolic acid, lactic acid, tartaric acid and malic acid. Hydroxycarboxylic acid having a hydroxyl group; carboxylic acid anhydride such as acetic anhydride, succinic anhydride, and maleic anhydride are exemplified.

The R ^4- OH preferably has a low molecular weight. In this case, when a coating film is formed of a titanium compound or when a coating film is formed by combining a titanium compound with another material, the refractive index of the coating film is formed. It is difficult to reduce the rate. That is, if R ^4- OH has a low molecular weight, it is difficult to lower the refractive index even if ^one R group remains in the coating film.

Further, the ^R 4 -OH is preferably the boiling point or decomposition temperature of 200 ° C. or less. In this case, when the obtained titanium compound is heat-treated, for example, when it is dried at 250 ° C. or lower, the unreacted R ^4- OH and R ⁴ groups substituted with R ³ are easily volatilized or decomposed, so that the coating film is coated. It is difficult to reduce the refractive index of titanium.

From the viewpoint of good viewpoint and compatible with titanium-based material as described above, R 4 ^-OH are acetic acid, propionic acid, is preferably one selected from the group consisting of oxalic acid, and lactic acid, it is acetic acid More preferred.

From the viewpoint of good aspect and titanium-based material compatible to enhance the transparency of the coating film, R 4 ^-OH are acetic acid, propionic acid and glycolic acid, selected tartaric, from the group of hydroxy carboxylic acids such as citric acid 1 It is preferably a seed.

As described above, the most preferred ^R 4 -OH are acetic acid, propionic acid.

The reaction between the titanium raw material and R ^4- OH can be carried out in a solvent.

The solvent is not particularly limited, but for example, it can be carried out in a polar solvent having at least one of an OH group and a carbonyl group. By carrying out the reaction in such a solvent, it becomes easy to prevent the reaction (for example, hydrolysis and condensation reaction) from proceeding rapidly. As a result, the obtained titanium compound is less likely to cause cloudiness or gelation, and can be a material capable of imparting excellent transparency and a high refractive index. The solvent used in the above reaction acts as a diluent and a terminal protectant in the production of the titanium compound, and the rapid progress of the reaction can be suppressed.

The polar solvent has a molecular structure having at least one of an OH group and a carbonyl group. When the protic solvent has an OH group, alcohols and glycols can be mentioned, and when the protic solvent has a carbonyl group, lactams and diketones can be mentioned. More preferred polar solvents include benzyl alcohol, ethylene glycol, N-methyl-2-pyrrolidone (NMP), acetylacetone and the like.

When a solvent is used, the amount of the solvent used is not limited, but for example, the concentration of the titanium raw material is set to 0.1 to 20% by weight in terms of the weight of titanium dioxide (TiO ₂ ) produced from the titanium raw material. Solvents can be used. In this case, the coating film formed by the titanium compound has high transparency, and the obtained titanium compound tends to be stable. Further, even if a coating film of a titanium compound is formed in a state containing the above-mentioned polar solvent, the film thickness is unlikely to be thinned. As a result, even when the titanium compound is used in combination with another material, it is easy to design the combination of the titanium compound and the other material. The concentration of the titanium raw material is more preferably 1 to 15% by weight in terms of the weight of titanium dioxide produced from the titanium raw material.

In the reaction in the above step, the mixing ratio of the titanium raw material represented by the formula (5) and R ^4- OH is not particularly limited, but R ^4- OH of 0.5 molar equivalent or more with respect to R ^{3 of} the titanium raw material. It is preferable to react. In other ^words, R 4 -OH, since reacts with ^R 3 -O site of titanium raw material represented by the formula ^{(5), R} 3 -O moles of sites to by ^number, moles of R 4 -OH It is preferable to use R ^4- OH so that the number (number) is 50% or more. In this case, the titanium compound obtained by sufficiently proceeding the reaction is more stabilized, and unreacted R ^4- OH and R ³ groups are unlikely to remain, so that the risk of a decrease in the refractive index is reduced.

A titanium raw ^material, the mixing ratio of the R 4 -OH, relative to ^{R 3} of the titanium material of the formula ^(5), it is preferred that the R 4 -OH and 0.8 molar equivalents or more. Further, from the viewpoint that unreacted R ^4- OH is unlikely to remain, the upper limit of the amount of R ^4- OH used is preferably 100 molar equivalents with respect to the titanium raw material represented by the formula (5). It is more preferably 10 molar equivalents and particularly preferably 5 molar equivalents.

The reaction in the above step may be carried out by heating. The heating temperature can be 50 ° C. or higher, preferably 80 ° C. or higher. The upper limit of the heating temperature is usually 200 ° C. The reaction time in the above step can be appropriately set, for example, 10 minutes or more, or 60 minutes or more.

More preferable reaction conditions are a heating temperature of 50 ° C. or higher and a reaction time of 10 minutes or longer. In this case, the reaction proceeds sufficiently, and a titanium compound that easily imparts high transparency and a refractive index can be obtained.

Further, the above heating may be performed in two or more steps. Specifically, after heating at 50 ° C. or higher for a certain period of time, the temperature can be further raised (for example, 100 ° C. or higher) and the reaction can be continued. Is.

The above reaction may be carried out in air or in an atmosphere of an inert gas such as nitrogen or argon. By-products produced during the reaction, for example, alkoxide-derived alcohols, and ester compounds produced by the reaction of these alcohols with carboxylic acids may be volatilized and removed by a reaction in an open system, or volatilized by purging. However, the removal may be promoted.

In the above reaction, an appropriate amount of water may be added so as not to cause a rapid hydrolysis reaction and condensation reaction (polymerization) and to promote the increase in molecular weight.

By going through the above steps, the desired titanium compound can be obtained. After the above steps, purification or the like may be performed if necessary. When the titanium compound is produced using a solvent, the solvent may be removed, or the titanium compound may be obtained as a solution without removing the solvent.

The titanium compound obtained by the above production method has each structural unit represented by the formulas (1) to (4) and has 4 or more Ti atoms.

In the above production method, R ^4- OH, which is a starting material, is unlikely to remain, and ^two R groups in the titanium raw material are also unlikely to remain, so that a titanium compound that easily imparts high transparency and a refractive index can be obtained.

<Titanium-based composition>
The titanium-based composition of the present embodiment contains the above-mentioned titanium compound and a polar solvent having at least one of an OH group and a carbonyl group. By applying such a titanium-based composition to a base material or the like, a coating film formed with a titanium compound can be formed.

Then, by, for example, heat-treating the coating film, the hydrolysis and condensation reaction of the titanium compound proceeds, and the titanium compound changes to TiO ₂ or a structure close thereto. This makes it possible for the coating film to have a high refractive index. Moreover, since this coating film is formed with the titanium compound, it has high transparency.

The polar solvent is the same as the polar solvent described in the method for producing a titanium compound.

In the titanium-based composition, the content of the titanium compound is not particularly limited. For example, at the time of preparing the titanium-based composition, the content of the titanium compound can be 0.01 to 60% by weight in terms of titanium oxide with respect to the total amount of the polar solvent and the titanium compound.

The method for preparing the titanium-based composition is not particularly limited. For example, a titanium-based composition can be prepared by mixing a predetermined amount of a titanium compound and the above-mentioned polar solvent by an appropriate method. Alternatively, when a polar solvent is used in the above-mentioned method for producing a titanium compound, the reaction solution after the reaction can be obtained as it is as a titanium-based composition. In this case, by-products and the like in the reaction solution may be removed if necessary.

The titanium-based composition may contain other components to the extent that its effect is not impaired.

Further, the method for forming the coating film from the titanium-based composition is not limited, and for example, a known method can be adopted.

<Resin composition>
The resin composition according to this embodiment contains the above titanium compound and a resin. Thereby, for example, a coating film (resin coating film) formed by having the titanium compound and the resin can be formed by applying a solution or a dispersion liquid of the resin composition to the base material.

Then, by subjecting the coating film to, for example, heat treatment, the hydrolysis and condensation reaction of the titanium compound proceeds, and the titanium compound changes to TiO ₂ or a structure close to this, thereby having a high refractive index. It can be a resin coating.

Further, since the titanium compound has an excellent affinity with the resin as described above, the titanium compound is likely to be uniformly dispersed in the resin and exist. As a result, the resin coating film formed is also excellent in transparency.

The type of the resin is not particularly limited, and various resins are exemplified.

Above all, the resin is preferably an organic resin and has two or more reactive functional groups. The reactive functional group is, for example, a group exhibiting photocurability or thermocurability, for example, a vinyl group (alkenyl group), an epoxy group, an acrylic group, an isocyanate group, a hydroxyl group, a carboxyl group, an amino group, or an amide group. , Carboxylic acid anhydride and the like.

More specifically, examples of the resin include thermosetting resins such as epoxy, acrylates, methacrylates, epoxy acrylates, photocurable resins such as epoxy methacrylate, and thermoplastic resins such as polyester and polycarbonate.

In the case of such an organic resin, the affinity with the titanium compound is particularly excellent, so that both are likely to be uniformly composited. As a result, the resin coating film has even better transparency and refractive index. Moreover, by reacting the reactive functional group with the titanium compound, both are more highly composited, so that the transparency and the refractive index of the resin coating film can be easily increased.

The resin is particularly preferably at least one selected from the group consisting of epoxy resins, acrylic resins and epoxy acrylate resins.

When the resin is a thermosetting resin, the titanium compound can act as a curing agent for the thermosetting resin, so that a separate curing agent may be unnecessary or may be reduced.

Further, the refractive index of the resin is preferably 1.60 or more and less than 2.0, and in this case, the refractive index of the resin coating film formed from the resin composition becomes higher.

Further, the resin preferably contains at least one of a fluorene skeleton and a naphthalene skeleton. A resin having such a skeleton can further improve the refractive index of the coating film.

Examples of the resin having a fluorene skeleton or a naphthalene skeleton include bisphenoxyethanol full orange glycidyl ether, bisphenol full orange glycidyl ether, bisnaphthol full orange glycidyl ether, biscresol full orange glycidyl ether, bisphenoxyethanol full orange acrylate, and bisphenoxyethanol full orange. Examples thereof include methacrylate and naphthalenediglycidyl ether. Further, polyester having a structure of bisphenoxyethanol fluorene, bisphenol fluorene, biscresol fluorene, bisnaphthol fluorene and the like can also be mentioned.

The resin composition is further described by the following general formula (6).

It may have a structure represented by.

The structure represented by the above formula (6) can be formed, for example, by reacting a Ti-OH moiety or a Ti-OR moiety of a titanium compound with an epoxy moiety such as an epoxy resin. For example, the structure represented by the formula (6) can be formed by reacting the epoxy moiety such as the above-mentioned bisphenoxyethanol full orange glycidyl ether with the Ti-OH moiety or the Ti-OR moiety of the titanium compound. When the titanium compound has a structure represented by the above formula (6) in this way, the refractive index of the coating film formed of the resin composition can be further improved.

The resin composition may contain other components to the extent that its effect is not impaired. Other components include, for example, solvents, light stabilizers, dispersion stabilizers and the like.

The resin coating film is a composite of the titanium compound and the resin. Such a resin coating film has excellent transparency and a refractive index because it contains a titanium compound as described above, and in addition to this, for example, it is desired to appropriately select the type of resin. Performance that matches the purpose of. For example, a crack prevention function can be imparted by appropriately selecting the type of resin.

Further, since the resin coating film formed from the resin composition has both high transparency and high refractive index, it is possible to make the thickness (thickness) of the coating film thicker than that of the conventional resin coating film. It can be applied to various uses.

In the resin composition, the mixing ratio of the titanium compound and the resin is not particularly limited, and for example, the titanium compound is set to 5 to 95% by weight in terms of titanium oxide (TiO ₂ ) with respect to the total amount of the resin and the titanium compound. be able to.

The method for preparing the resin composition is not particularly limited. For example, a resin composition can be prepared by mixing a predetermined amount of the titanium compound and the above resin by an appropriate method. Alternatively, in the step of the reaction in the production method of the above-mentioned titanium compound, in the presence of a resin, by carrying out the reaction of the titanium raw material and R ⁴ -OH of the formula (5), a resin composition prepared In some cases it can be done.

When mixing the resin and the titanium compound, the resin and the titanium compound can be melt-kneaded or mechanically mixed, but from the viewpoint of maintaining transparency, the resin and the titanium compound are mixed in the presence of a solvent. It is preferable to mix.

Further, the method for forming the coating film from the resin composition is not limited, and for example, a known method can be adopted.

<Titanium solid>
The titanium-based solid of the present embodiment is obtained by heating the titanium compound to 50 ° C. or higher, and is composed of the structural units of the above formulas (1) and (2).

By heating the titanium compound to 50 ° C. or higher, a reaction such as dehydration condensation of the titanium compound occurs, a Ti—O—Ti bond is formed, and a titanium-based solid can be formed. More specifically, the hydrolysis reaction and condensation reaction of R ¹ -O sites occur in the titanium compound, occur dehydration-condensation of decomposition and Ti-OH structure of a titanium compound, Ti-O-Ti bond is formed To. The titanium-based solid thus obtained is formed with the structural units of the above formulas (1) and (2) as main components.

Therefore, the titanium-based solid has a high refractive index, high transparency, and can improve heat resistance and chemical resistance.

In particular, since the obtained titanium-based solid is formed from a raw material containing the titanium-based compound, it can have a refractive index of 1.75 or more, for example.

The titanium-based solid can be obtained by a production method having a step of heating a raw material containing a titanium-based compound to 50 ° C. or higher. By this heating step, the water splitting reaction and the condensation reaction of the titanium-based compound proceed sufficiently, and it is easy to obtain a titanium-based solid having more constituent units of the above formula (2). As a result, the titanium-based solid can have a particularly high refractive index. A more preferable heating temperature is 100 ° C. or higher, more preferably 150 ° C. or higher, and particularly preferably 200 ° C. or higher, from the viewpoint of volatilization of the solvent and reactivity of the titanium-based compound. Further, when the heating temperature is 400 ° C. or higher, the structure is similar to that of TiO ₂ , so that the strength of the titanium-based solid is also improved.

The specific embodiment of the titanium-based solid is not particularly limited, and is, for example, a coating film, a film, a plate, a thin film, or the like.

Further, even in the above resin composition, a titanium-based solid can be formed by heating as described above. This titanium-based solid is obtained by a step of heating the resin composition to 50 ° C. or higher, and is composed of the structural units of the above formulas (1) and (2).

The titanium-based solid in this case can be obtained as a resin coating film containing a resin and a titanium-based compound containing the constituent unit of the above formula (2) as a main component, depending on the heating temperature, or the resin component is burnt out and the above formula is used. It can be formed as a porous membrane containing the structural unit of (2) as a main component.

Even when a titanium-based solid is formed using the resin composition, a reaction such as dehydration condensation of the titanium compound occurs by heating, a Ti—O—Ti bond is formed, and the titanium-based solid can be formed. Therefore, the titanium-based solid thus formed also has a high refractive index, high transparency, and can improve heat resistance and chemical resistance.

In particular, since the obtained titanium-based solid is formed from a raw material containing the titanium-based compound, it can have a refractive index of 1.75 or more, for example.

When forming a titanium-based solid using the resin composition, the heating temperature may be adjusted according to the type of resin.

When the resin is a photocurable resin, it may be heated and then cured by ultraviolet rays or the like.

When the titanium-based solid is a resin coating film, the heating temperature is preferably 350 ° C. or lower, more preferably 300 ° C. or lower, from the viewpoint of preventing decomposition of the resin component when heating the resin composition. Since the resin coating film thus obtained is formed by using a titanium compound having an excellent affinity for the resin, it can have excellent transparency and a high refractive index.

On the other hand, when the titanium-based solid is a porous film containing the structural unit of the above formula (4) as a main component, the heating temperature is preferably 400 ° C. or higher, more preferably 450 ° C. or higher, from the viewpoint of burning out the resin component. preferable.

Since the titanium-based solid as described above has high transparency and high refractive index, it is suitable as a high refractive index material and can be applied to various fields.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the aspects of these Examples.

(Refractive index measurement)
Refractive index measurement is calculated by measuring the reflection spectrum of a coating formed on a silicon wafer in a measurement range of 420 to 950 nm using a spectroscopic reflection spectrum measuring device (manufactured by Filmometry), and fitting using the spectrum. Was done.

(Example 1)
3.43 g of titanium tetra n-butoxide was added to 96.6 g of N-methyl-2-pyrrolidone as a solvent so as to be 0.8% by weight in terms of TiO ₂ . 12 g of acetic acid was added thereto, and the mixture was stirred for 10 minutes. The acetic acid added was 20-fold molar equivalent relative to titanium tetra n-butoxide (5-fold molar equivalent relative to the butoxy group). Then, 0.15 g of water was added, and the mixture was stirred at 50 ° C. for 60 minutes. Then, the temperature was raised to 100 ° C. and the mixture was stirred for 15 minutes to obtain a pale yellow transparent solution.

When this solution was spin-coated on a silicon substrate and heated at 150 ° C. for 120 minutes to measure the refractive index, the refractive index was 1.85. Alternatively, when the refractive index was measured by heating at 250 ° C. for 120 minutes, the refractive index was 1.95.

(Example 2)
12.1 g of titanium tetra n-butoxide tetramer was added to 87.9 g of N-methyl-2-pyrrolidone as a solvent so as to be 4% by weight in terms of TiO ₂ . 6 g of acetic acid was added thereto, and the mixture was stirred for 10 minutes. The acetic acid added was 10 molar equivalents relative to titanium tetra n-butoxide (1 molar equivalent relative to the butoxy group). Then, the temperature was raised to 100 ° C. and the mixture was stirred for 15 minutes to obtain a pale yellow transparent solution.

As shown in FIG. 1, the solution (titanium-based composition) containing the titanium compound obtained in Example 2 is found to be transparent.

When this solution was spin-coated on a silicon substrate and heated at 150 ° C. for 120 minutes to measure the refractive index, the refractive index was 1.94. Alternatively, when the refractive index was measured by heating at 250 ° C. for 120 minutes, the refractive index was 2.03.

As shown in FIG. 2, even if the spin-coated film formed from the solution containing the titanium compound obtained in Example 2 is placed on the surface of the printed matter, the characters and patterns of the printed matter can be clearly visually recognized. It is recognized that the film is highly transparent (titanium-based solid).

(Example 3)
A solution was obtained in the same manner as in Example 2 except that the solvent was changed to benzyl alcohol instead of N-methyl-2-pyrrolidone. The obtained solution was almost colorless and transparent.

When this solution was spin-coated on a silicon substrate and heated at 150 ° C. for 120 minutes to measure the refractive index, the refractive index was 1.88. Alternatively, when the refractive index was measured by heating at 250 ° C. for 120 minutes, the refractive index was 1.97.

(Example 4)
The solution obtained in Example 2 and a 10 wt% solution of N-methyl-2-pyrrolidone of bisphenoxyethanol full orange glycidyl ether (BPEFG) were mixed so as to have a TiO ₂ equivalent weight: BPEFG weight = 2: 1.

When this solution was spin-coated on a silicon substrate and heated at 150 ° C. for 120 minutes to measure the refractive index, the refractive index was 1.83. Alternatively, when the refractive index was measured by heating at 250 ° C. for 120 minutes, the refractive index was 1.89.

(Comparative Example 1)
120 g (2 mol) of acetic acid was added to 142.1 g (0.5 mol) of titanium tetraisopropoxide, the mixture was stirred for 15 minutes, and 550 g of water was added. The pH of this dispersion was 2.5. A large amount of translucent precipitate was generated, but when heating was performed after stirring for 60 minutes, all the precipitate was dissolved at 60 ° C.

Then, after stirring at normal pressure (0.1 MPa) at 80 ° C. for 5 hours, water was added to the reaction solution to prepare a total of 800 g, and then ultrasonic waves were applied to obtain a translucent and uniform titania dispersion. Was done. When this dispersion was dried and TEM-observed, nanoparticles of 3 nm were observed.

When this dispersion was applied to glass by spin coating and dried at 150 ° C. for 120 minutes, a transparent coating film was obtained, but the refractive index was 1.65. When further heated at 250 ° C. for 120 minutes, the refractive index was 1.69.
(Comparative Example 2)
83 g of N-methyl-2-pyrrolidone was added to 17.0 g (0.05 mol) of titanium tetra n-butoxide and stirred, but the mixture was separated and the solution was not uniform. 0.72 g of water was added to this solution, and the mixture was stirred, but a white precipitate was formed and a transparent solution could not be obtained.

(Comparative Example 3)
When n-butanol was added to 17.0 g (0.05 mol) of titanium tetra n-butoxide to make 100 g, and the mixture was stirred, a transparent and uniform solution was obtained. When this solution was spin-coated on a silicon substrate and dried, it became cloudy and a transparent coating film could not be obtained.

(Comparative Example 4)
Titanium tetra n-butoxide tetramer was added to 9.7 g (0.01 mol) to make 100 g, and the mixture was stirred to obtain a transparent and uniform solution. When this solution was spin-coated on a silicon substrate, dried, and then heated at 150 ° C. for 120 minutes, it became cloudy and a transparent coating film could not be obtained.

As described above, since the titanium compounds of Comparative Examples 2 to 4 do not have the structural units represented by the general formulas (1) and (2), a transparent coating film could not be obtained. Since it does not have a substituent such as an acetyl group as in Comparative Example 3, hydrolysis and polymerization are likely to occur due to moisture in the air, and particle formation is a cause of cloudiness.

Claims (17)

The following general formulas (1) and (2)
(In formula (1), R ¹ is either an acetyl group or a propionyl group)
It has each structural unit represented by and
A titanium compound having 4 or more Ti atoms. The following general formulas (3) and (4)
(In the formula (3) and (4), R ² is a alkyl group, hydrogen, or acetyl group or a propionyl group, a plurality of R ² of formula (3) may be the same or different, wherein ( 4 a plurality of ^{R 2} in) may be the same or different, may be the same or different from ^{R 1} and ^{R 2} and ^{R 2} of formula (4) in equation (3) in equation (1))
The titanium compound according to claim 1, further comprising at least one of the structural units represented by. The titanium compound according to claim 2, wherein 50% or more of the total amount of all R ¹ and all R ² is at least one of the acetyl group and the propionyl group. The method for producing a titanium compound according to any one of claims 1 to 3.
The following general formula (5)
(In formula (5), R ³ is an alkyl group, and a plurality of R ³ in formula (5) may be the same or different, and n is an integer of 1 or more).
A method for producing a titanium compound, which comprises a step of reacting a titanium raw material represented by (R4) with R ^4- OH (R ⁴ is either an acetyl group or a propionyl group). The production method according to claim ⁴ , wherein 0.8 mol equivalent or more of the R ^4- OH is reacted with R ^{3 of the} titanium raw material represented by the above formula (5). The production method according to claim 4 or 5, wherein the reaction is carried out in a polar solvent having at least one of an OH group and a carbonyl group. The production method according to any one of claims 4 to 6, wherein the reaction is carried out by heat treatment at 50 ° C. or higher for 10 minutes or longer. A titanium-based composition comprising the titanium compound according to any one of claims 1 to 3 and a polar solvent having at least one of an OH group and a carbonyl group. A resin composition containing the titanium compound according to any one of claims 1 to 3 and a resin. The resin composition according to claim 9, wherein the resin is an organic resin and has two or more reactive functional groups. The resin composition according to claim 9 or 10, wherein the resin is at least one selected from the group consisting of an epoxy resin, an acrylic resin, and an epoxy acrylate resin. The resin composition according to any one of claims 9 to 11, wherein the resin has a refractive index of 1.60 or more and less than 2.0. The resin composition according to any one of claims 9 to 12, wherein the resin contains at least one of a fluorene skeleton and a naphthalene skeleton. A step of heating the titanium compounds described above 50 ° C. to claim 1, the equation (2) A method of manufacturing a structural unit including titanium based solid. Any resin composition according to item 1 comprising the step of heating above 50 ° C., the equation (2) A method of manufacturing a structural unit including titanium based solid of claim 9-13. A titanium-based solid containing the structural unit of the above formula (2) , which has a refractive index of 1.75 or more. The following general formula (6)
The resin composition according to any one of claims 9 to 13, which has a structure represented by.