JP6238593B2 - Film forming composition - Google Patents

Description

  The present invention relates to a film-forming composition, a film-forming method using the film-forming composition, a film formed using the film-forming composition, a method for producing the film-forming composition, and a film-forming composition. The present invention relates to a method for improving the refractive index of a film formed using a composition.

  In recent years, flat panel displays (FPD) such as a liquid crystal display (LCD), a plasma display (PDP), and an electroluminescence display (EL) have been widely used as image display devices. In these displays, in order to prevent the reflection of the background that causes a decrease in contrast, it is desired to prevent the reflection of the background. In order to prevent reflection, it is effective to suppress reflection on the surface of the screen. Therefore, an antireflection film in which a high refractive film and a low refractive film are laminated is usually provided on the surface of these displays.

  As a method of forming a highly refractive film when forming an antireflection film, for example, a resin is applied to a titanium oxide dispersion liquid containing rutile titanium oxide fine particles surface-treated with an oxide and an organometallic compound. In addition, there is known a method of applying a prepared high refractive film forming material onto a substrate and then drying and curing the coated film (Patent Document 1).

JP 2007-084374 A

  However, the composition for forming a high refractive film described in Patent Document 1 has a problem that the refractive index of a film formed using the composition is not always sufficient.

  The present invention has been made in view of the above problems, and a film having an improved refractive index can be formed by blending a specific amount of a high-boiling polar solvent having a boiling point of 170 ° C. or higher under atmospheric pressure. A film-forming composition, a film-forming method using the film-forming composition, a film formed using the film-forming composition, a method for producing the film-forming composition, and the film It aims at providing the improvement method of the refractive index of the film | membrane formed using the composition for formation.

  The inventors of the present invention provide a film-forming composition containing an organic resin, inorganic nanoparticles, and a solvent with a mass of 20 to 100% by mass with respect to the total of the mass of the organic resin and the mass of the inorganic nanoparticles. It has been found that the above-mentioned problems can be solved by blending a high-boiling polar solvent having a boiling point of 170 ° C. or higher under atmospheric pressure as a solvent, and the present invention has been completed. Specifically, the present invention provides the following.

The first aspect of the present invention includes (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent,
The (S) solvent includes a high boiling point polar solvent having a boiling point of 170 ° C. or higher under atmospheric pressure,
It is a composition for film formation whose content of the said high boiling point polar solvent is 20-100 mass% with respect to the sum total of the mass of the said (A) organic resin, and the said (B) inorganic nanoparticle.

The second aspect of the present invention includes a step of applying the film forming composition according to the first aspect to form a coating film;
And a step of drying the coating film.

  The third aspect of the present invention is a film formed using the film forming composition according to the first aspect.

The fourth aspect of the present invention is directed to a film-forming composition comprising (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent.
As said (S) solvent, the boiling point under atmospheric pressure of 170-100 degreeC or more of 20-100 mass% with respect to the sum total of the mass of said (A) organic resin and the said (B) inorganic nanoparticle is 170 degreeC or more. By blending the high boiling polar solvent, the film forming composition containing the high boiling polar solvent is used rather than the film formed using the film forming composition not containing the high boiling polar solvent. A method for producing a film-forming composition that improves the refractive index of a film to be formed.

The fifth aspect of the present invention is a method for improving the refractive index of a film formed using a film-forming composition comprising (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent. There,
The atmospheric pressure of 20-100 mass% with respect to the sum total of the mass of the said (A) organic resin and the mass of the said (B) inorganic nanoparticle as said (S) solvent with respect to the said film formation composition. By blending a high-boiling polar solvent having a boiling point of 170 ° C. or higher below, the high-boiling polar solvent is included rather than a film formed using the film-forming composition not containing the high-boiling polar solvent. This is a method for improving the refractive index of a film, which improves the refractive index of a film formed using the film-forming composition.

  According to the present invention, a film-forming composition capable of forming a film having an improved refractive index by blending a specific amount of a high-boiling polar solvent having a boiling point of 170 ° C. or higher under atmospheric pressure, and the film A film forming method using the forming composition, a film formed using the film forming composition, a manufacturing method of the film forming composition, and the film forming composition are formed. A method for improving the refractive index of a film can be provided.

<< Film-forming composition >>
The film forming composition according to the present invention includes (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent. (S) A solvent contains the high boiling polar solvent whose boiling point under atmospheric pressure is 170 degreeC or more. Here, the film-forming composition containing (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent is blended with a predetermined amount of a high-boiling polar solvent, which will be described later. The refractive index of the cured film formed using the forming composition is higher than that of the cured film formed using the film forming composition that does not contain a high-boiling polar solvent. The refractive index of a film formed using the film forming composition of the present invention is a film generally called a high refractive film. The refractive index of a general high refractive film is preferably 1.6 or more, more preferably 1.7 or more and 1.8 or less.

  The film-forming composition may contain (C) a photopolymerizable monomer and (D) a photopolymerization initiator in addition to the components described above. In this case, the film-forming composition can be a photosensitive film-forming composition. Hereinafter, the components contained in the film-forming composition and the method for producing the film-forming composition will be described in order.

[(A) Organic resin]
The composition for film formation contains (A) organic resin. Here, the organic resin refers to a resin having a main chain composed of a bond containing a carbon atom. For example, a resin whose main chain is a siloxane bond or a bond containing no carbon such as —Si—Si— bond is not included in the organic resin even if it has an organic group in the side chain. (A) The kind of organic resin will not be specifically limited if it is resin mix | blended with the composition for film formation conventionally used in order to form a film | membrane with a refractive index of 1.6 or more.

  From the point that the transparency, refractive index, mechanical properties and solvent resistance of the film to be formed are good, and (B) the dispersibility of the inorganic nanoparticles, (A) among the organic resins, (a1) A copolymer comprising a structural unit derived from a compound having a phenolic hydroxyl group and a structural unit derived from a compound having a polymerizable group (hereinafter, also referred to as (a1) polymerizable phenolic resin), and (a2) A resin having a cardo structure (hereinafter also referred to as (a2) cardo resin) is preferable. Hereinafter, (a1) polymerizable phenolic resin and (a2) cardo resin will be described in order.

((A1) polymerizable phenolic resin)
The (a1) polymerizable phenolic resin includes a structural unit having a predetermined functional group and is not particularly limited. The polymerizable phenolic resin may be a polymer of an unsaturated compound such as a (meth) acrylic acid ester. Or a polycondensation polymer such as polyester. Among (a1) polymerizable phenolic resins, an unsaturated compound polymer is preferred from the viewpoint of easy preparation and availability of the resin and transparency of the formed film.

  (A1) The polymerizable phenolic resin may be a random copolymer or a block copolymer. (A1) The amount of the structural unit derived from the compound having a phenolic hydroxyl group in the polymerizable phenolic resin is preferably 20 to 50 mol% with respect to the number of moles of all the structural units in the resin. Moreover, the amount of the structural unit derived from the compound having a polymerizable group in the polymerizable phenolic resin (a1) is preferably 50 to 80 mol% with respect to the number of moles of all the structural units in the resin. (A1) When the polymerizable phenolic resin contains a structural unit derived from a compound having a phenolic hydroxyl group and a structural unit derived from a compound having a polymerizable group in such an amount, mechanical properties And it is easy to form a film having excellent transmittance.

  (A1) The mass average molecular weight of the polymerizable phenolic resin (Mw: measured value by gel permeation chromatography (GPC) in terms of polystyrene) is preferably 10,000 to 30,000. When (a1) polymerizable phenolic resin having a molecular weight in such a range is used, it is easy to achieve both the applicability of the film-forming composition and the mechanical properties of the film formed using the film-forming composition. .

  (A1) When the polymerizable phenolic resin is a polymer of an unsaturated compound, the compound that gives the structural unit derived from the compound having a phenolic hydroxyl group is not particularly limited. For example, vinylphenols, allylphenols, vinyls Examples include loxyphenols, allyloxyphenols, and hydroxyphenyl (meth) acrylate.

  (A1) When the polymerizable phenolic resin is a polymer of an unsaturated compound, with respect to the structural unit derived from the compound having a polymerizable group, the polymerizable group is either a polymerizable group or a polymerizable group and another functional group. The group is not particularly limited as long as it can undergo a crosslinking reaction. As the polymerizable group, a functional group capable of undergoing a thermal crosslinking reaction between the polymerizable groups or a functional group capable of undergoing a thermal crosslinking reaction with a phenolic hydroxyl group is preferable. Among the thermally crosslinkable polymerizable groups, an epoxy group or an oxetanyl group is preferable from the viewpoint of excellent reactivity.

Among the polymerizable phenolic resins (a1), a resin composed of a unit represented by the following formula (1) and a unit represented by the formula (2) is preferable. (A1) The polymerizable phenolic resin may contain one or more units represented by the formula (1) in combination.

In Formula (1) and Formula (2), R ⁰ independently represents a hydrogen atom or a methyl group, R ¹ represents a single bond or an alkylene group having 1 to 5 carbon atoms, and R ² represents a carbon atom. represents the number of 1 to 5 alkyl groups, ^{R 3} represents a monovalent organic group having a heat crosslinking, a is an integer of 1-5, b represents an integer of 0 to 4, a + b is 5 It is as follows.

In the unit represented by the formula (1), R ⁰ is preferably a methyl group.

R ¹ represents a single bond or an alkylene group having 1 to 5 carbon atoms. Examples of the alkylene group include a methylene group, ethylene group, propylene group, isopropylene group, n-butylene group, isobutylene group, tert-butylene group, pentylene group, isopentylene group, and neopentylene group. As the alkylene group, a methylene group and an ethylene group are preferable.

At least one hydroxyl group is bonded to the benzene ring of the unit represented by the formula (1). A which shows the number of bonds of a hydroxyl group is an integer of 1-5, and 1 is more preferable. The unit represented by the formula (1) has a hydroxyl group at the 4-position on the benzene ring when the position where the divalent group represented by —O—R ¹ — is bonded to the benzene ring is the 1-position. Is preferred.

A linear or branched alkyl group having 1 to 5 carbon atoms may be bonded as R ² to the benzene ring of the unit represented by the formula (1). Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, and neopentyl group. R ² is preferably a methyl group or an ethyl group. b represents an integer of 0 to 4, and 0 is more preferable.

The unit represented by the formula (1) is preferably a unit represented by the following formula (a1-1) or formula (a1-2).

In the unit represented by the formula (2), ^{R 0} and ^{R 1} are the same as ^{R 0} and ^{R 1} described in unit represented by formula (1). The unit represented by the formula (2) has a monovalent organic group having thermal crosslinkability as R ³ . A heat-crosslinkable group refers to a group that crosslinks when heated. As the thermally crosslinkable group, an organic group containing either an epoxy group or an oxetanyl group is preferable. Among these, from the viewpoint of reactivity, R ³ is preferably an organic group having an epoxy group. (A1) The reactive phenolic resin may contain one or more units represented by the formula (2) in combination.

  As the unit represented by the formula (2), units represented by the following formulas (a1-3) to (a1-15) are preferable.

In the above formulas (a1-3) to (a1-15), R ⁰ and R ¹ are the same as those in the formulas (1) and (2). R ⁴ each independently represents an alkylene group having 1 to 20 carbon atoms. R ⁵ each independently represents a hydrogen atom or a methyl group. R ⁶ independently represents an alkylene group having 1 to 8 carbon atoms. w represents an integer of 0 to 10.

Among the units represented by the above formulas (a1-3) to (a1-15), a unit represented by the formula (a1-3), a unit represented by the formula (a1-4), and the formula (a1 -The unit represented by 5 ) is preferable. Of the units represented by the formula (a1-3) and the units represented by the formula (a1-4), a unit in which R ⁰ is a methyl group is preferable. Among the units represented by formula (a1-5), a unit in which R ⁰ is a methyl group and R ¹ is a methylene group is preferable.

((A2) cardo resin)
The cardo resin is not particularly limited as long as it contains a cardo structure having 9,9-diphenylfluorene as a core. Among the cardo resins, a resin represented by the following formula (a-1) is preferable.

In the formula ^{(a-1), X} a represents a group represented by the following formula (a-2).

In the formula (a-2), R ^a1 independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a halogen atom, and R ^a2 independently represents a hydrogen atom or a methyl group. , W ^a represents a single bond or a group represented by the following formula (a-3).

In the formula (a-1), Y ^a represents a residue obtained by removing an acid anhydride group (—CO—O—CO—) from a dicarboxylic acid anhydride. Examples of dicarboxylic acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, methyltetrahydro Examples thereof include phthalic anhydride and glutaric anhydride.

Further, in the above formula ^(a-1), Z a represents a residue obtained by removing two acid anhydride groups from a tetracarboxylic acid dianhydride. Examples of tetracarboxylic dianhydrides include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, biphenyl ether tetracarboxylic dianhydride, and the like.
Moreover, in said formula (a-1), m shows the integer of 0-20.

  (A2) The mass average molecular weight of the cardo resin is preferably 1000 to 40000, more preferably 2000 to 30000. By using a cardo resin having a molecular weight within the above range, a film-forming composition capable of forming a film having sufficient heat resistance and film strength can be obtained.

  The content of the organic resin (A) described above in the film-forming composition is not particularly limited as long as the object of the present invention is not impaired. The content of the (A) organic resin in the film-forming composition is preferably 60% by mass or less, based on the total of the mass of (A) the organic resin and (B) the mass of the inorganic nanoparticles. 60 mass% is more preferable, 10-50 mass% is further more preferable, and 10-30 mass% is the most preferable. By blending the amount of (A) organic resin in such a range into the film-forming composition, the film-forming composition can be obtained while setting the refractive index of the film formed using the film-forming composition to a desired value. The applicability of the object and the strength of the formed film can be improved.

[(B) Inorganic nanoparticles]
(B) Inorganic nanoparticles are components that contribute to increasing the refractive index of a film formed using the film-forming composition. Moreover, the film | membrane excellent in hardness and light resistance can be formed by making the composition for film formation contain the (B) inorganic nanoparticle.

  The average particle size of the (B) inorganic nanoparticles is preferably 500 nm or less, and preferably 2 to 100 nm, from the viewpoint of ensuring the transparency of the film.

  (B) The inorganic nanoparticles are preferably metal oxide fine particles. Suitable examples of the metal oxide include titanium oxide, zirconium oxide, aluminum oxide, barium titanate, cerium oxide, tin oxide, zinc oxide, tantalum oxide, manganese oxide, nickel oxide, iron oxide, silicon oxide, niobium oxide, Examples thereof include lanthanum oxide and gadolinium oxide. Among these, titanium oxide or zirconium oxide is preferable because it is easy to form a film having a particularly high refractive index. (B) Two or more kinds of inorganic nanoparticles can be mixed and used. Moreover, (B) inorganic nanoparticles may contain composite particles in which two or more of the above materials are combined.

  The content of (B) inorganic nanoparticles in the film-forming composition is not particularly limited as long as a film having an improved refractive index desired can be formed using the film-forming composition. The content of (B) inorganic nanoparticles in the film-forming composition is preferably 40% by mass or more based on the total of (A) the mass of the organic resin and (B) the mass of the inorganic nanoparticles. -90 mass% is more preferable, 50-90 mass% is further more preferable, and 70-90 mass% is the most preferable. By blending the amount of (B) inorganic nanoparticles in such a range into the film-forming composition, the refractive index of the film formed using the film-forming composition is set to a desired value, and the film-forming composition is used. The applicability | paintability of a composition and the intensity | strength of the film | membrane formed can be made favorable.

[(S) solvent]
(S) A solvent contains the high boiling polar solvent whose boiling point under atmospheric pressure is 170 degreeC or more. The boiling point of the high boiling polar solvent is more preferably 190 ° C. or higher. Further, the boiling point of the high boiling polar solvent is preferably 300 ° C. or less, and more preferably 250 ° C. or less.

The high-boiling polar solvent is not particularly limited as long as it has been widely known to those skilled in the art as a polar solvent and has a predetermined boiling point. As the high-boiling polar solvent, those having an SP value of 10 (cal / cm ³ ) ^1/2 are preferable, those having 10 to 30 (cal / cm ³ ) ^1/2 are more preferable, and 10 to 24 Those having (cal / cm ³ ) ^1/2 or more are particularly preferred.

  By blending a predetermined amount of the high boiling polar solvent having such a boiling point into the film forming composition, the refractive index of the film formed using the film forming composition can be remarkably improved. In addition, when a high-boiling polar solvent having such a boiling point is used, it is easy to suppress the generation of beads when forming a coating film and the cloudiness in the formed film.

The SP value (cal / cm ³ ) ^1/2 known as the solubility parameter is used as an indicator of the compatibility and affinity of a plurality of substances, and is defined by the formula represented by the following formula (I). The
δ = (ΔEV / V0) ^1/2 ÷ 2.046 [(cal / cm ³ ) ^1/2 ] (I)

In the formula (I), ΔEV [10 ⁶ N · m · mol ⁻¹ ] is the heat of evaporation of the solvent, and V0 [m ³ · mol ⁻¹ ] is the volume per 1 mol of the solvent. The difference in SP value between two substances is closely related to the energy required for the two substances to be compatible. The smaller the SP value is, the less energy is required for the two substances to be compatible. It will be small. That is, when two substances are present, generally, the smaller the difference in SP value, the higher the affinity and the higher the compatibility.

  The SP value can be obtained by experiments, but can also be obtained by calculation. Several methods for obtaining the SP value by calculation have been proposed. For example, for a relatively high amount of material, the Small method (PA Small: J. Appl. Chem, 3, 71 (1953)). Can be used. For relatively low molecular weight materials, the HIdebrand method (JH HIldbrand and RL Scott: The SolbIlty of Non-Electrolytes, ACS Monograph SerIs, 1950) can be used. By using these methods, the SP value can be obtained as a more appropriate value, and the dissolution parameter can be easily obtained.

Specific examples of the high boiling polar solvent include the solvents shown in Table 1 below. The boiling points in Table 1 are the boiling points under atmospheric pressure.

  The content of the high-boiling polar solvent in the film-forming composition is 10 to 100% by mass with respect to the total of the mass of the (A) organic resin and the mass of the (B) inorganic nanoparticles, and 20 to 20%. It is preferable that it is 80 mass%. When the content of the high-boiling polar solvent is 10% by mass or more, the effect of increasing the refractive index of the film formed using the film-forming composition is obtained, and when the content is 100% by mass or less, the composition The coating performance and transparency of the film can be maintained.

  (S) Solvents, together with high-boiling polar solvents, have been conventionally blended into film-forming compositions to improve the solubility of resins and inorganic nanoparticles and to adjust the concentration of film-forming compositions. A solvent other than the boiling polar solvent may be included.

  Examples of solvents other than the high boiling polar solvent include ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, propylene glycol monomethyl ether acetate, 3-methoxy-1-butyl acetate, 3- Methyl-3-methoxy-1-butyl acetate, ethyl acetoacetate, propylene carbonate, etc., methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, acetylacetone, cyclopentanone, cyclohexanone, cycloheptanone, diethyl ether, diisopropyl ether, di-n- Butyl ether, diphenyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether , Toluene, xylene, ethyl benzoate, naphthalene, 1,2,3,4-tetrahydronaphthalene and the like.

  The total amount of the (S) solvent in the film-forming composition is not particularly limited, and is appropriately determined in consideration of the solid content concentration of the film-forming composition. 1-50 mass% is preferable and, as for solid content concentration of the composition for film formation, 2-50 mass% is more preferable.

  In addition to the components described above, the film-forming composition may contain (C) a photopolymerizable monomer, (D) a photopolymerization initiator, etc. for the purpose of imparting photosensitivity (photopolymerization performance). .

[(C) Photopolymerizable monomer]
(C) It does not specifically limit as a photopolymerizable monomer, A conventionally well-known monofunctional monomer and a polyfunctional monomer can be used.

  Monofunctional monomers include (meth) acrylamide, methylol (meth) acrylamide, methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, propoxymethyl (meth) acrylamide, butoxymethoxymethyl (meth) acrylamide, N-methylol ( (Meth) acrylamide, N-hydroxymethyl (meth) acrylamide, (meth) acrylic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, crotonic acid, 2-acrylamide- 2-methylpropane sulfonic acid, tert-butylacrylamide sulfonic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (Meth) acryloyloxy-2-hydroxypropyl phthalate, glycerin mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dimethylamino (meth) acrylate, glycidyl (meth) acrylate, 2,2,2-trifluoroethyl ( And (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, and half (meth) acrylate of a phthalic acid derivative. These monofunctional monomers can be used alone or in combination of two or more.

  On the other hand, as the polyfunctional monomer, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol Di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexane glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol triacrylate, pentaerythritol Tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol di (meta Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2,2-bis (4- (meth) acryloxydi Ethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, ethylene glycol diglycidyl ether di (meth) Acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate ester di (meth) acrylate, glycerin triacrylate, glycerin polyglycidyl ether poly (Meth) acrylate, urethane (meth) acrylate (ie, tolylene diisocyanate), reaction product of trimethylhexamethylene diisocyanate, hexamethylene diisocyanate and 2-hydroxyethyl (meth) acrylate, methylenebis (meth) acrylamide, (meth) acrylamide methylene Examples thereof include polyfunctional monomers such as ethers, polyhydric alcohols and N-methylol (meth) acrylamide condensates, and triacryl formal. These polyfunctional monomers can be used alone or in combination of two or more.

  (C) The content of the photopolymerizable monomer is preferably more than 0% by mass and 150% by mass or less, and more preferably more than 0% by mass and 100% by mass or less with respect to (A) the organic resin. By using the photopolymerizable monomer (C) in an amount in the above range, it is easy to obtain a film-forming composition that is cured well by exposure.

[(D) Photopolymerization initiator]
(D) It does not specifically limit as a photoinitiator, A conventionally well-known photoinitiator can be used.

  Specific examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1- [4- (2-hydroxyethoxy) phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2 -Methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis (4-dimethylaminophenyl) ketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, ethanone 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl], 1- (o-acetyloxime), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-benzoyl- 4′-methyldimethylsulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 4-dimethylamino-2-ethylhexylbenzoic acid, 4 -Dimethylamino-2-isoamylbenzoic acid, benzyl-β-methoxyethyl acetal, benzyldimethyl ketal, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, methyl o-benzoylbenzoate, 2,4-diethylthioxanthone, 2-chlorothioxanthone , 2,4-dimethylthioxanthone, 1-chloro-4-propoxythioxanthone, thioxanthene, 2-chlorothioxanthene, 2,4-diethylthioxanthene, 2-methylthioxanthene, 2-isopropylthioxanthene, 2-ethylanthraquinone , Octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, azobisisobutyronitrile, benzoyl peroxide, cumene peroxide, 2-mercaptobenzoimidar, 2-mercaptobenzoxazole, 2-mercapto Benzothiazole, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophe ) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer 2,4,5-triarylimidazole dimer, benzophenone, 2-chlorobenzophenone, 4,4′-bisdimethylaminobenzophenone (ie, Michler's ketone), 4,4′-bisdiethylaminobenzophenone (ie, ethyl Michler's) Ketone), 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether , Benzoin butyl ether, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone, p-dimethylaminoacetophenone, p-tert- Butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, α, α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, pentyl-4-dimethylaminobenzoate, 9-phenyl Acridine, 1,7-bis- (9-acridinyl) heptane, 1,5-bis- (9-acridinyl) pentane, 1,3-bis- (9- Cridinyl) propane, p-methoxytriazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2- [2- (5 -Methylfuran-2-yl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine, 2- [2- (furan-2-yl) ethenyl] -4,6-bis (trichloromethyl)- s-triazine, 2- [2- (4-diethylamino-2-methylphenyl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine, 2- [2- (3,4-dimethoxyphenyl) ethenyl ] -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4- Toxistyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-n-butoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-bis-trichloromethyl -6- (3-bromo-4-methoxy) phenyl-s-triazine, 2,4-bis-trichloromethyl-6- (2-bromo-4-methoxy) phenyl-s-triazine, 2,4-bis- Trichloromethyl-6- (3-bromo-4-methoxy) styrylphenyl-s-triazine, 2,4-bis-trichloromethyl-6- (2-bromo-4-methoxy) styrylphenyl-s-triazine, “IRGACURE OXE02, IRGACURE OXE01, IRGACURE 369, IRGACURE 651, IRGAC RE 907 "(trade name: manufactured by BASF)," NCI-831 "(trade name: ADEKA Co., Ltd.), and the like. These photopolymerization initiators can be used alone or in combination of two or more.

  It is preferable that content of a photoinitiator is 0.5-20 mass% with respect to the mass of (A) organic resin. By setting it as said range, sufficient heat resistance and chemical-resistance can be acquired, a coating-film formation ability can be improved, and hardening failure can be suppressed.

[(E) Other ingredients]
The film-forming composition may contain various additives conventionally used in film-forming compositions, in addition to the components described above. A preferable example of the additive added to the film-forming composition is a surfactant. The surfactant is not particularly limited, and known components such as a fluorine-based surfactant and a silicon-based surfactant can be used. When the film-forming composition contains a surfactant, unevenness of the coating film thickness when the film-forming composition is applied by a spin coater is suppressed.

[Method for producing film-forming composition]
After a predetermined amount of each of the components described above is mixed, the mixture is uniformly stirred to obtain a film-forming composition.

<< Film Formation Method >>
A method for forming a film using the film forming composition described above is not particularly limited as long as it can form a film having a desired film thickness and characteristics. The film is usually formed by a method including a step of applying a film-forming composition to form a coating film and a step of drying the formed coating film.

  Examples of the method for applying the film-forming composition include a method using a contact transfer type coating device such as a roll coater, reverse coater or bar coater, or a non-contact type coating device such as a spinner (rotary coating device) or a curtain flow coater. It is done.

  Next, the coating film thus formed is dried to form a film. The method for drying the coating film is not particularly limited, and examples thereof include reduced pressure and heating, and heating is preferable. Since the film-forming composition contains a high-boiling polar solvent having a boiling point of 170 ° C. or higher under atmospheric pressure, the temperature when drying the coating film is preferably 70 to 150 ° C., and 80 to 120 ° C. Is more preferable.

  When the film-forming composition contains (A) an organic resin having a thermally crosslinkable polymerizable group such as an epoxy group, in addition to the heating for drying after the application, a heat curing treatment is further added. May be. As heating temperature of heat-hardening process, 150-250 degreeC is preferable and 200-250 degreeC is more preferable. By this heat curing treatment, the crosslinking of the organic resin proceeds, and the mechanical properties of the formed film can be improved.

  When the film-forming composition is a photosensitive composition containing (C) a photopolymerizable monomer and (D) a photopolymerization initiator, the coating film may be exposed before and after drying the coating film. The coating film is exposed by irradiating active energy rays such as ultraviolet rays and excimer laser light.

  The coating film may be exposed in a position-selective manner, for example, by a method such as exposure through a mask. When the coating film is selectively exposed, the exposed coating film is not developed by using a developer selected in consideration of the type of (A) organic resin contained in the film-forming composition. By removing the exposed portion, a patterned film can be formed.

  Even when the film-forming composition is a photosensitive composition, a heat curing treatment may be further added. The mechanical properties of the formed film can be improved by applying the same heat curing treatment as described above before or after drying the coated film or after developing the exposed coated film.

  The film formed by the above-described method has a refractive index increased by blending a predetermined amount of a high-boiling polar solvent as the (S) solvent, and is used for various applications such as an antireflection film. The

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the following Example at all.

[Examples 1-4 and Comparative Examples 1-3]
Components of the types and amounts described in Table 2 below were uniformly mixed to prepare a film-forming composition having a solid content concentration of 25% by mass. In Table 2, “High-boiling polar solvent ratio” is a mass ratio (mass%) of the high-boiling polar solvent to the total of the mass of the organic resin and the mass of the inorganic nanoparticles in the film-forming composition.

In Examples 1 to 4 and Comparative Examples 1 to 3, a resin having the following structural units and having a mass average molecular weight of 7000 was used as the organic resin. The number on the lower right of each structural unit represents the content (mol%) of each structural unit in the organic resin.

In Examples 1 to 4 and Comparative Examples 1 to 3, Omonova's PolyFox PF656 was used as the surfactant.
The solvents described in Table 2 are as follows. The boiling point is at atmospheric pressure.
PGMEA: Propylene glycol monomethyl ether acetate, boiling point 145 ° C
PGME: Propylene glycol monomethyl ether, boiling point 120 ° C., SP value 10.2 (cal / cm ³ ) ^1/2
γBL: γ-butyrolactone, boiling point 204 ° C., SP value 12.6 (cal / cm ³ ) ^1/2

In Examples 1 to 4 and Comparative Examples 1 to 3, Optolake (TiO ₂ fine particles, manufactured by JGC Catalysts & Chemicals, Inc., number average particle size 10 nm) was used as the inorganic nanoparticles.

A cured film having a film thickness of 600 nm was formed using the obtained film forming compositions of Examples and Comparative Examples, and the transparency, refractive index, and bead of the formed cured film were evaluated.
Specifically, the film-forming composition was applied to the surface of a 6-inch Si substrate using a spin coater (Mikasa Spinner IH-360S, manufactured by Mikasa Corporation), and then dried at 100 ° C. for 2 minutes. . Thereafter, as a heat curing treatment, the coating film was heated at 200 ° C. for 5 minutes to form a cured film.

(Transparency evaluation)
The formed cured film was visually observed, and the transparency was evaluated based on the presence or absence of white turbidity. The evaluation criteria for transparency are as follows.
○: No cloudiness is observed.
X: Cloudiness is observed.

(Refractive index evaluation)
The refractive index of the formed cured film was measured as a refractive index at a wavelength of 600 nm using a spectroscopic ellipsometer (WUVRAM VUV-VASE). The measured refractive index values are shown in Table 2.

[Bead evaluation]
The cross section of the formed cured film was observed using a scanning electron microscope (trade name: S-4500, manufactured by Hitachi High-Technology Corporation), and the width of the unevenness (convex part) at the end of the film was measured. The bead was evaluated. The bead evaluation criteria are as follows.
(Double-circle): The width | variety of the convex part of a film | membrane edge part is less than 0.5 mm.
○: The width of the convex portion at the film end is 2.0 mm or less.
X: The width | variety of the convex part of a film | membrane edge part is 2.1 mm or more.

  According to Table 2, 20-100 mass% with respect to the sum total of the mass of an organic resin, and the mass of an inorganic nanoparticle with respect to the composition for film formation containing organic resin, an inorganic nanoparticle, and a solvent. When the high boiling polar solvent is added, it can be seen that a film having a significantly increased refractive index can be formed as compared with the case where the high boiling polar solvent is not included.

[Examples 5 to 8 and Comparative Examples 4 to 6]
The film forming compositions of Examples 1 to 4 and Comparative Examples 1 to 3 were each diluted with PGME so as to have a solid content concentration of 5% by mass, and Examples 5 to 8 and Comparative Examples 4 to 6 were diluted. A film-forming composition was obtained.
A cured film having a film thickness of 90 nm was formed using the obtained film forming compositions of Examples and Comparative Examples, and the refractive index of the formed cured film was evaluated. Formation and evaluation of the cured film were performed in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3 except that the film thickness was changed. Table 3 shows the evaluation results of the cured films formed using the film forming compositions of Examples 5 to 8 and Comparative Examples 4 to 6.

  According to Table 2 and Table 3, with respect to the composition for film formation containing organic resin, inorganic nanoparticle, and a solvent, it is 20 ~ with respect to the sum total of the mass of organic resin, and the mass of inorganic nanoparticle. When 100% by mass of a high-boiling polar solvent is blended, the refractive index is significantly higher than when no high-boiling polar solvent is contained, regardless of the solid content concentration of the film-forming composition and the film thickness of the film to be formed. It can be seen that an enhanced film can be formed.

[Examples 9 to 12 and Comparative Examples 7 to 9]
In Examples 9-12 and Comparative Examples 7-9, NMP (N-methyl-2-pyrrolidone) was used instead of γBL. NMP has a boiling point of 204 ° C. under atmospheric pressure and an SP value of 11.2 (cal / cm ³ ) ^1/2 . Preparation of a film-forming composition and curing formed using the film-forming composition in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3, except that NMP is used instead of γBL The film was evaluated. Table 4 shows the evaluation results of the cured films formed using the film forming compositions of Examples 9 to 12 and Comparative Examples 7 to 9.

  According to Table 4, 20-100 mass% with respect to the sum total of the mass of an organic resin, and the mass of an inorganic nanoparticle with respect to the composition for film formation containing organic resin, an inorganic nanoparticle, and a solvent. When the high boiling polar solvent is added, it can be seen that a film having a significantly increased refractive index can be formed as compared with the case where the high boiling polar solvent is not included.

[Examples 13 to 16 and Comparative Examples 10 to 12]
The film forming compositions of Examples 9 to 12 and Comparative Examples 7 to 9 were each diluted with PGME so as to have a solid content concentration of 5% by mass, and Examples 13 to 16 and Comparative Examples 10 to 12 were diluted. A film-forming composition was obtained.
A cured film having a film thickness of 90 nm was formed using the obtained film forming compositions of Examples and Comparative Examples, and the refractive index of the formed cured film was evaluated. Formation and evaluation of the cured film were performed in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3 except that the film thickness was changed. Table 5 shows the evaluation results of the cured films formed using the film forming compositions of Examples 13 to 16 and Comparative Examples 10 to 12.

  According to Table 4 and Table 5, with respect to the total of the mass of an organic resin and the mass of an inorganic nanoparticle with respect to the composition for film formation containing organic resin, an inorganic nanoparticle, and a solvent, it is 20- When 100% by mass of a high-boiling polar solvent is blended, the refractive index is significantly higher than when no high-boiling polar solvent is contained, regardless of the solid content concentration of the film-forming composition and the film thickness of the film to be formed. It can be seen that an enhanced film can be formed.

[Examples 17 to 20 and Comparative Examples 13 to 15]
In Examples 17 to 20 and Comparative Examples 13 to 15, the organic resin was changed to the resin (A-1) described below, and PGMEA was changed to MBA (3-methoxybutyl acetate, boiling point 173 ° C.). The preparation of the film forming composition and the evaluation of the cured film formed using the film forming composition in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3 except that went. Table 6 shows the evaluation results of cured films formed using the film forming compositions of Examples 17 to 20 and Comparative Examples 13 to 15. In Comparative Examples 13 and 14, the refractive index could not be measured due to the rough surface of the formed cured film.

(Resin (A-1))
As the resin (A-1), a resin obtained according to the following method was used.
First, in a 500 ml four-necked flask, 235 g of bisphenolfluorene type epoxy resin (epoxy equivalent 235), 110 mg of tetramethylammonium chloride, 100 mg of 2,6-di-tert-butyl-4-methylphenol, and 72.0 g of acrylic acid Was heated and dissolved at 90 to 100 ° C. while blowing air at a rate of 25 ml / min. Next, the temperature was gradually raised while the solution was clouded, and the solution was heated to 120 ° C. to be completely dissolved. At this time, the solution gradually became transparent and viscous, but stirring was continued as it was. During this time, the acid value was measured, and heating and stirring were continued until the acid value was less than 1.0 mgKOH / g. It took 12 hours for the acid value to reach the target value. And it cooled to room temperature and obtained the bisphenol fluorene type epoxy acrylate represented by the following transparent formula (a-4) colorless and transparent.

Next, after adding 600 g of 3-methoxybutyl acetate to 307.0 g of the bisphenolfluorene type epoxy acrylate thus obtained and dissolving, 80.5 g of benzophenonetetracarboxylic dianhydride and 1 g of tetraethylammonium bromide were added. The mixture was gradually heated and reacted at 110 to 115 ° C. for 4 hours. After confirming disappearance of the acid anhydride group, 38.0 g of 1,2,3,6-tetrahydrophthalic anhydride was mixed and reacted at 90 ° C. for 6 hours to obtain Resin (A-1). The disappearance of the acid anhydride group was confirmed by IR spectrum.
In addition, this resin (A-1) is corresponded to the compound represented by the said Formula (a-1).

[Examples 21 to 24 and Comparative Examples 16 to 18]
The film forming compositions of Examples 17 to 20 and Comparative Examples 13 to 15 were each diluted with PGME so that the solid content concentration was 5% by mass, and Examples 21 to 24 and Comparative Examples 16 to 18 were diluted. A film-forming composition was obtained.
A cured film having a film thickness of 90 nm was formed using the obtained film forming compositions of Examples and Comparative Examples, and the refractive index of the formed cured film was evaluated. Formation and evaluation of the cured film were performed in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3 except that the film thickness was changed. Table 7 shows the evaluation results of the cured films formed using the film forming compositions of Examples 21 to 24 and Comparative Examples 16 to 18. In Comparative Examples 16 and 17, the refractive index could not be measured due to the rough surface of the formed cured film.

  According to Table 6 and Table 7, with respect to the sum total of the mass of organic resin and the mass of inorganic nanoparticles with respect to the composition for film formation containing organic resin, inorganic nanoparticles, and a solvent, it is 20- When 100% by mass of a high-boiling polar solvent is blended, it can be seen that a film having a high refractive index can be formed regardless of the solid content concentration of the film-forming composition and the film thickness of the film to be formed.

[Comparative Examples 19 to 21]
The film-forming compositions of Comparative Examples 16 to 18 were the same as in Example 4 except that γBL blended in the film-forming composition as a high-boiling polar solvent was changed to the following MEDG, MBA, or PGMEA. I got a thing. MEDG (methyl ethyl diglycol) is a nonpolar solvent having a boiling point under atmospheric pressure of 176 ° C. and an SP value of 8.3 (cal / cm ³ ) ^1/2 . MBA (3-methoxybutyl acetate) is a nonpolar solvent having a boiling point under atmospheric pressure of 173 ° C. and an SP value of 9.3 (cal / cm ³ ) ^1/2 . PGMEA (propylene glycol monomethyl ether acetate) is a low boiling point solvent having a boiling point of 145 ° C. under atmospheric pressure.
About the film formation composition of Comparative Examples 19-21, it carried out similarly to Example 4, and evaluated the transparency of the cured film formed using the film formation composition. Table 8 shows the evaluation results of the cured films formed using the film forming compositions of Comparative Examples 19 to 21.

  According to Table 8, when the film-forming composition contains a predetermined amount of a high-boiling polar solvent, the cured film formed using the film-forming composition has good transparency. When a nonpolar solvent or a low-boiling solvent is blended in the inorganic film, the inorganic nanoparticles are not uniformly dispersed in the film-forming composition, which makes it difficult to form a transparent cured film.

[Example 25 and Comparative Example 22]
Components of the types and amounts described in Table 9 were mixed to obtain film forming compositions of Example 25 and Comparative Example 22. The solid content concentration of the obtained film-forming composition was 28.5% by mass. The same organic resin, inorganic nanoparticles, and surfactant as in Example 1 were used. The following PI-1 and PI-2 were used as photopolymerization initiators. Dipentaerythritol hexaacrylate was used as the photopolymerizable monomer.

A cured film having a film thickness of 600 nm was formed using the obtained film forming compositions of Examples 25 and Comparative Example 22, and the refractive index of the formed cured film was evaluated.
Specifically, the film-forming composition was spin-coated on the surface of a 6-inch Si substrate with a spin coater (Mikasa Spinner IH-360S, manufactured by Mikasa Corporation), and then the coating film was dried at 100 ° C. for 2 minutes. Thus, a 600 nm coating film was formed. Then, an exposure device (MPA-600FA, manufactured by Canon Inc.) by an exposure dose of 200 mJ / cm ^2, were exposed coating film. Furthermore, the cured film was formed by adding a heat curing treatment at 200 ° C. for 5 minutes to the coated film after exposure. The refractive index of the formed cured film was measured in the same manner as in Example 1.

  According to Table 9, even when a photopolymerizable monomer and a photopolymerizable initiator are blended in the film forming composition, the film forming composition containing an organic resin, inorganic nanoparticles, and a solvent is used. On the other hand, the refractive index of the cured film formed can be remarkably improved by blending 20 to 100% by mass of a high boiling polar solvent with respect to the total mass of the organic resin and the inorganic nanoparticles. I understand.

Claims (11)

(A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent,
The (S) solvent includes a high boiling point polar solvent having a boiling point of 190 ° C. or higher and 205 ° C. or lower under atmospheric pressure,
The content of the high-boiling polar solvent, wherein a 20 to 100% by weight relative to the total mass of (A) the mass of the organic resin (B) inorganic nanoparticles, a film forming composition ,
The (A) organic resin is a copolymer containing (a1) a structural unit derived from a compound having a phenolic hydroxyl group and a structural unit derived from a compound having a polymerizable group, or (a2) a cardo Ri resin der having a structure,
The high-boiling polar SP value of the solvent 10~12.6 (cal ^/ cm ³⁾ Ru ^1/2 der, film-forming composition. Wherein (a2) a resin having a cardo structure, a resin having a (a2) cardo structure represented by the following formula (a-1), film-forming composition of claim 1.

(In the formula ^{(a-1), X} a represents a group represented by the following formula (a-2).)

(In formula (a-2), R ^a1 independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a halogen atom, and R ^a2 independently represents a hydrogen atom or a methyl group. W ^a represents a single bond or a group represented by the following formula (a-3).)

(A1) the compound having a phenolic hydroxyl group is at least one selected from the group consisting of vinylphenols, allylphenols, vinyloxyphenols, allyloxyphenols, and hydroxyphenyl (meth) acrylate;
The film-forming composition according to claim 1 , wherein the polymerizable group is at least one selected from the group consisting of an epoxy group and an oxetanyl group. The high-boiling polar solvent is at least one selected from the group consisting of γ-butyrolactone (γBL) and N-methyl-2-pyrrolidone (NMP). A film forming composition.   The film forming composition according to claim 1, wherein the (S) solvent further contains a solvent other than the high boiling polar solvent.   Content of the said (B) inorganic nanoparticle is 40 mass% or more with respect to the sum total of the mass of the said (A) organic resin, and the mass of the said (B) inorganic nanoparticle. The film-forming composition according to any one of the above.   The content of the (B) inorganic nanoparticles is 50% by mass or more based on the total of the mass of the (A) organic resin and the mass of the (B) inorganic nanoparticles. The film-forming composition according to any one of the above. Applying the film-forming composition according to any one of claims 1 to 7 to form a coating film;
And a step of drying the coating film.   The film | membrane formed using the composition for film formation of any one of Claims 1-7. For the film-forming composition comprising (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent,
As the (S) solvent, the boiling point at atmospheric pressure of 20 to 100% by mass with respect to the total mass of the (A) organic resin and the (B) inorganic nanoparticles is 190 ° C. or higher and 205 ° C. by following der Ri SP value is blended 10~12.6 (cal ^/ cm ^{3) 1/2} der Ru high boiling polar solvent, using the high-boiling polar solvent does not contain film-forming composition The manufacturing method of the film forming composition which improves the refractive index of the film | membrane formed using the film | membrane forming composition which mix | blended the said high boiling point polar solvent rather than the film | membrane formed. A method for improving the refractive index of a film formed using a film-forming composition comprising (A) an organic resin, (B) inorganic nanoparticles, and (S) a solvent,
The atmospheric pressure of 20-100 mass% with respect to the sum total of the mass of the said (A) organic resin and the mass of the said (B) inorganic nanoparticle as said (S) solvent with respect to the said film formation composition. by der Ri SP value boiling point of 190 ° C. or higher 205 ° C. or less under the blending 10~12.6 (cal ^/ cm ^{3) 1/2} der Ru high-boiling polar solvent, the high-boiling polar solvent A method for improving the refractive index of a film, wherein the refractive index of a film formed using the film-forming composition containing the high-boiling polar solvent is higher than that of a film formed using a film-forming composition that does not contain the film.