Composition, film, laminate, and optical member

Abstract

Provided are: a composition from which a film having high flexibility and suppressed cracking and peeling during dicing can be obtained; and a film, a laminate, and an optical member which are obtained using the same.　The composition contains chain-shaped silica fine particles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin.

Description

Composition, film, laminate, and optical member

[0001] The present invention relates to a composition, a film, a laminate, and an optical component.

[0002] Porous silicon oxide films have a wide range of industrial applications due to their low refractive index, transparency, electrical insulation, etc. In particular, applications that utilize their low refractive index include anti-reflection coatings for electronic device displays, automotive panels, lighting fixtures, solar energy devices, camera lenses, face shields, eyeglasses, optical waveguides, and cladding layers for optical fibers.

[0003] For example, Patent Document 1 discloses a method for producing a binder liquid for forming a silicon oxide thin film, which has excellent substrate adhesion and is suitable for forming a porous silicon oxide thin film. Patent Document 2 also proposes a method for producing a coating liquid for forming a silicon oxide thin film, which involves subjecting a hydrolyzable silane compound to a hydrolysis and condensation reaction, and mixing the resulting reaction product, a binder liquid for forming a silicon oxide thin film, with silica fine particles. Patent Document 2 also proposes a porous silicon oxide film with excellent antifogging properties.

[0004] JP 2019-23269 A JP 2021-182134 A

[0005] However, the porous silicon oxide films described in Patent Documents 1 and 2 have the risk of cracking or peeling when the porous silicon oxide film is laminated on a substrate and then diced.

[0006] The present invention has been made in view of the above problems, and aims to provide a composition that can produce a film that is highly flexible and inhibits cracking and peeling during dicing processing, and a film, laminate, and optical component obtained therefrom.

[0007] As a result of intensive research to solve the above problems, the inventors discovered that a film made of a composition containing chain silica microparticles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin can be made more flexible, and cracking and peeling during dicing can be suppressed, thereby completing the present invention.

[0008] That is, the gist of the present invention is as follows.

[0009] [1] A composition containing linear silica microparticles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin. [2] The composition according to [1] above, wherein the hydrophilic resin has hydroxyl groups. [3] The composition according to [1] or [2] above, wherein the content of hydroxyl groups directly bonded to the main chain of the hydrophilic resin is 35 mol% or less. [4] The composition according to any one of [1] to [3] above, wherein the content of the hydrophilic resin is more than 1 part by mass per 100 parts by mass of the linear silica microparticles and the alkoxysilane hydrolysis condensate. [5] The composition according to any one of [1] to [4] above, wherein the content of the alkoxysilane hydrolysis condensate is 5 to 30% by mass per 100% by mass of the linear silica microparticles, the alkoxysilane hydrolysis condensate, and the hydrophilic resin. [6] The composition according to any one of [1] to [5], wherein the content of the chain silica fine particles is 60 to 90% by mass, relative to 100% by mass of the total of the chain silica fine particles, the alkoxysilane hydrolysis condensate, and the hydrophilic resin. [7] The composition according to any one of [1] to [6], wherein the weight-average molecular weight of the alkoxysilane hydrolysis condensate is 1,000 to 5,000. [8] The composition according to any one of [1] to [7], wherein the average primary particle diameter of the chain silica fine particles is 5 to 100 nm. [9] The composition according to any one of [1] to [8], wherein the average degree of polymerization of the hydrophilic resin is 200 to 2,000.

[10] A film comprising the composition according to any one of [1] to [9].

[11] A film containing a hydrophilic resin and having a porosity of 10 to 80%.

[12] The film according to

[10] above, having a thickness of 3,000 nm to 20,000 nm.

[13] The film according to

[10] or

[12] above, having a porosity of 10 to 80%.

[14] The film according to any one of

[10] to

[13] above, having a refractive index of 1.15 to 1.40.

[15] The film according to any one of

[10] to

[14] above, having a pore size of 0.1 to 50 nm.

[16] A laminate of the film according to any one of

[10] to

[15] above and a substrate.

[17] The laminate according to

[16] above, wherein the substrate is glass.

[18] An optical element comprising the laminate according to

[17] above.

[0010] As described above, the composition of the present invention contains chain silica fine particles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin, which makes it possible to provide a film or laminate that is highly flexible and can suppress cracking and peeling during dicing.

[0011] The composition, film, and laminate according to the present invention will be described in detail below with reference to their embodiments, but the present invention is not limited to the following description, and can be practiced by making appropriate modifications other than those exemplified below, as long as the purpose of the present invention is not impaired.

[0012] In this specification, the word "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0013] [Composition] The components of the composition of the present invention are described in detail below: The composition of the present invention contains chain silica fine particles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin.

[0014] By molding the composition of the present invention, a film can be produced as a molded article. Furthermore, by laminating the film on a substrate, a laminate can be obtained. This, for example, improves the flexibility of the film, and can prevent cracking or peeling when the laminate is diced to fit the product size. This results in a film with excellent adhesion and flexibility to the substrate and a refractive index suitable for optical applications.

[0015] The form of the composition of the present invention is not particularly limited and may be liquid or solid, but typical examples include the following two: (I) a coating liquid containing chain silica fine particles, a hydrophilic resin, an alkoxysilane hydrolysis condensate, and a solvent; and (II) a film containing chain silica fine particles, a hydrophilic resin, and an alkoxysilane hydrolysis condensate.

[0016] [Chain-like silica fine particles] Chain-like silica fine particles refer to a continuous chain of a plurality of primary particles directly bonded by chemical bonds such as siloxane bonds without any intervening joints made of other materials. They may be in a linear shape or in a two-dimensionally or three-dimensionally curved shape. Furthermore, the chain-like silica fine particles are preferably silica fine particles having an average primary particle diameter of, for example, about 5 to 30 nm, which are continuous to an average length of about 30 to 200 nm. Here, the shape of the chain-like silica fine particles can be observed using an electron microscope (SEM, etc.). The average primary particle diameter is usually determined by the specific surface area (m ２ / g), the average primary particle diameter is a value given by the formula: average primary particle diameter = (2720 / specific surface area). The average length can be measured by dynamic light scattering.

[0017] Such chain silica microparticles have large interparticle voids in the deposited state, so that the refractive index of the film can be reduced.On the other hand, when silica particles other than chain silica microparticles, for example, spherical silica particles, are used, in order to reduce the refractive index, it is necessary to blend a large amount of spherical silica particles.In this case, the content ratio of the matrix structure other than the spherical silica particles becomes small, so that the haze increases and the appearance is significantly deteriorated.In the present invention, by using chain silica microparticles, it is possible to achieve both a low refractive index and an excellent appearance.

[0018] The average primary particle diameter of the chain silica microparticles is preferably 6 nm or more, more preferably 7 nm or more. By making the average primary particle diameter of the chain silica microparticles 6 nm or more, the refractive index of the film can be reduced. On the other hand, the average primary particle diameter of the chain silica microparticles is preferably 100 nm or less, preferably 50 nm or less, more preferably 30 nm or less. By making the average primary particle diameter of the chain silica microparticles 100 nm or less, a film of a desired film thickness can be easily formed, and the film surface roughness and light scattering can be reduced, thereby reducing haze.

[0019] Specific examples of chain silica fine particles include colloidal silica such as "SNOWTEX (registered trademark)-OUP" (average length: 40 to 100 nm), "SNOWTEX (registered trademark)-UP" (average length: 40 to 100 nm), "SNOWTEX (registered trademark) PS-M" (average length: 80 to 150 nm), "SNOWTEX (registered trademark) PS-MO" (average length: 80 to 150 nm), "SNOWTEX (registered trademark) PS-S" (average length: 80 to 120 nm), "SNOWTEX (registered trademark) PS-SO" (average length: 80 to 120 nm), "IPA-ST-UP" (average length: 40 to 100 nm), "MEK-ST-UP" (average length: 40 to 100 nm), and "PGME-ST-UP" (average length: 40 to 100 nm), all manufactured by Nissan Chemical Industries, Ltd., and "Fine Cataloid F-120" manufactured by JGC Catalysts and Chemicals Industries, Ltd. If necessary, it may be preferable to use a solvent-substituted dispersion medium. Commercially available dispersion media include methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate, but these dispersion media can be appropriately replaced with other components depending on the application.

[0020] The content of the chain silica fine particles is preferably 60 to 90% by mass as a ratio ("mass of chain silica fine particles" / "mass of chain silica fine particles + mass of alkoxysilane hydrolysis condensate + mass of hydrophilic resin") to the total 100% by mass of the chain silica fine particles, alkoxysilane hydrolysis condensate, and hydrophilic resin. If the content of the chain silica fine particles is 60% by mass or more, the porosity within the film increases, making it possible to lower the refractive index. 65% by mass or more is more preferred, and 70% by mass or more is particularly preferred. On the other hand, if the content is 90% by mass or less, the adhesion to the substrate and the mechanical strength of the film are further improved. 85% by mass or less is more preferred, and 80% by mass or less is particularly preferred.

[0021] [Alkoxysilane Hydrolysis Condensate] The alkoxysilane hydrolysis condensate contained in the composition of the present invention is a compound having a siloxane bond, which is a compound obtained by hydrolysis and condensation of an alkoxysilane. The method for producing the alkoxysilane hydrolysis condensate is not particularly limited, but it is generally produced from a hydrolyzable silane compound or a multimer of a hydrolyzable silane compound using water and an organic solvent. A composition produced from this hydrolyzable silane compound or a multimer of a hydrolyzable silane compound, water, and an organic solvent is called a silicate oligomer.

[0022] The alkoxysilane hydrolysis condensate of the present invention preferably has a weight-average molecular weight of 1,000 to 5,000. If the weight-average molecular weight of the alkoxysilane hydrolysis condensate is 1,000 or more, the silicate oligomer containing the alkoxysilane hydrolysis condensate is less likely to gel, resulting in good storage stability. It is more preferably 1,500 or more, and particularly preferably 2,000 or more. Furthermore, if it is 5,000 or less, adhesion to the substrate is improved, suppressing cracking and peeling during dicing. It is more preferably 4,000 or less, and particularly preferably 3,000 or less. Such a weight-average molecular weight corresponds to a polymer having an average degree of polymerization n of 2 to 100.

[0023] The weight-average molecular weight is a value measured by gel permeation chromatography (GPC) under the following conditions: Solvent: tetrahydrofuran Apparatus: TOSOH HLC-8220GPC Column: TOSOH TSKgel Super HM-N (two columns) and HZ1000 (one column) connected together Column temperature: 40°C Sample concentration: 0.01% by mass Flow rate: 0.6 ml / min Calibration curve: PEG (a calibration curve based on a four-point cubic approximation of molecular weights of 20,000, 4,000, 1,000, and 200 was used).

[0024] The concentration of alkoxy hydrolysis condensate in silicate oligomer is preferably 15% by mass or less, more preferably 10% by mass or less, particularly preferably 8% by mass or less.When the concentration of alkoxy hydrolysis condensate is 15% by mass or less, the stability of the solution is improved, and the dispersibility when mixed with chain silica microparticles is further improved.On the other hand, from the viewpoint of film shape efficiency, the concentration of alkoxy hydrolysis condensate in silicate oligomer is preferably 0.1% by mass or more, more preferably 0.2% by mass or more.Such silicate oligomer is transparent, and the turbidity measured by using a kaolin turbidimeter is usually 10 or less.

[0025] The organic solvent contained in the silicate oligomer is preferably a hydrophilic solvent. The hydrophilic solvent is not particularly limited, but generally includes alcohols such as methanol, ethanol, propanol, and butanol; cellosolves such as ethyl cellosolve, butyl cellosolve, and propyl cellosolves; and glycols such as ethylene glycol, propylene glycol, and hexylene glycol. These solvents may be used alone or in combination of two or more. The content of the organic solvent in the silicate oligomer is not particularly limited, but is typically 40% to 99% by mass.

[0026] The hydrolyzable silane compound is a silane compound having a hydrolyzable group such as an alkoxy group, an alkoxyalkoxy group, an acyloxy group, an aryloxy group, an aminoxy group, an amide group, a ketoxime group, an isocyanate group, a halogen atom, etc. Known hydrolyzable silane compounds include mono- to tetra-functional compounds, depending on the number of hydrolyzable groups.

[0027] In the present invention, an alkoxysilane compound is preferably used as the hydrolyzable silane compound. Examples of the alkyl group of the alkoxy group (—OR) include lower alkyl groups such as methyl, ethyl, propyl, and butyl.

[0028] Representative examples of alkoxysilane compounds include dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS), tetramethoxysilane (TMOS), dimethyldiethoxysilane (DMDES), methyltriethoxysilane (MTES), tetraethoxysilane (TEOS), etc. Commercially available dimethyldimethoxysilane (DMDMS) is usually a solution with a purity of 99% by mass.

[0029] A polymer of a hydrolyzable silane compound is formed by polymerizing (oligomerizing) the above-mentioned monomers through condensation. In this reaction, a silanol group (-Si-OH) is first formed by hydrolysis of the alkoxy group. At the same time, an alcohol (R-OH) is produced. Next, a siloxane bond (-Si-O-Si-O-) is formed by (dehydration) condensation of the silanol group, and this condensation is repeated to form a siloxane oligomer. As the polymer of the alkoxysilane compound, a polymer of tetramethoxysilane in which R is a methyl group or a polymer of tetraethoxysilane in which R is an ethyl group is preferred in terms of the hydrolysis property and condensation property of the alkoxy group.

[0030] The polymer structure can be linear, branched, cyclic, or network structure. A tetraalkoxysilane polymer having a linear structure is represented by the following general formula (I): RO(Si(OR) ２ O) ｎ R...(I)

[0031] In general formula (I), R is an alkyl group, and n represents the degree of polymerization of the polymer. Usually available polymers are compositions of polymers with different n's, and therefore have a molecular weight distribution. The degree of polymerization is represented by the average n.

[0032] The degree of polymerization of a tetrafunctional hydrolyzable silane compound such as tetraalkoxysilane or its polymer is sometimes expressed as "silica content." The "silica content" refers to the amount of silica (SiO ２The "silica content" is the mass ratio of the compound (parts by mass) to the total silica content of the compound, and is obtained by stably hydrolyzing the compound, calcining it, and measuring the amount of silica produced. The "silica content" also indicates the proportion of silica produced per molecule of the compound, and is a value calculated using the following general formula (II): Silica content (parts by mass) = Degree of polymerization × SiO ２ Molecular weight of the compound / molecular weight of the compound (II)

[0033] In the present invention, a polymer having a degree of polymerization n of usually 2 to 100, preferably 2 to 70, and more preferably 2 to 50 is used. It is convenient to use a commercially available product as such a polymer. As the degree of polymerization n increases, the molecular weight of the resulting alkoxysilane hydrolysis condensate increases, the molecular weight distribution broadens, and the viscosity increases.

[0034] Commercially available polymeric hydrolyzable silane compounds include MKC Silicate MS51, MKC Silicate MS56, MKC Silicate MS57, and MKC Silicate MS56S (all of which are polymeric tetramethoxysilanes) manufactured by Mitsubishi Chemical Corporation; Methyl Silicate 51 (a polymeric tetramethoxysilane), Methyl Silicate 53A, Ethyl Silicate 40, and Ethyl Silicate 48 (all of which are polymeric tetraethoxysilanes) manufactured by Colcoat Co., Ltd.; and Ethyl Silicate 40 and Silicate 45 (all of which are polymeric tetraethoxysilanes) manufactured by Tama Chemicals Co., Ltd.

[0035] The alkoxysilane hydrolysis condensate of the present invention is preferably produced using a hydrolyzable silane composition containing a bifunctional hydrolyzable silane compound and a hydrolyzable silane compound multimer, with the content of the hydrolyzable silane compound multimer being 50% by mass or more. The proportion of the multimer in this hydrolyzable silane composition is preferably 70% by mass or more. If the proportion of the multimer in the hydrolyzable silane composition is 70% by mass or more, a branched, cyclic, or network structure is appropriately formed in the reaction composition, thereby further improving adhesion between the film and the substrate. It is more preferably 75% by mass or more. On the other hand, the proportion of the multimer in the hydrolyzable silane composition is preferably 90% by mass or less. If the proportion of the multimer in the hydrolyzable silane composition is 90% by mass or less, gelation is less likely to occur and storage stability is improved. Furthermore, the proportion of the bifunctional hydrolyzable silane compound, which is the monomer, in the hydrolyzable silane composition is preferably 10% by mass or more and 30% by mass or less. When the proportion of the bifunctional hydrolyzable silane compound is 10% by mass or more, the silicate oligomer containing the obtained alkoxysilane hydrolysis condensate is less likely to gel and has better storage stability. On the other hand, when the proportion is 30% by mass or less, the coating property during film formation is better. This proportion is more preferably 25% by mass or less.

[0036] The conditions for the hydrolysis and condensation reaction are preferably those described in JP 2021-182134 A. This reaction is carried out by continuously dropping an aqueous acid catalyst solution into a hydrophilic solvent solution containing the hydrolyzable silane composition under stirring.

[0037] The content of the alkoxysilane hydrolysis condensate is preferably 5 to 30% by mass as a ratio to the total of the chain silica fine particles, the alkoxysilane hydrolysis condensate, and the hydrophilic resin ("mass of alkoxysilane hydrolysis condensate" / "mass of chain silica fine particles + mass of alkoxysilane hydrolysis condensate + mass of hydrophilic resin"). If the proportion of the alkoxysilane hydrolysis condensate is too low, the film formability decreases, and if the proportion of the alkoxysilane hydrolysis condensate is too high, the refractive index of the film increases. The content of the alkoxysilane hydrolysis condensate is more preferably 5 to 25% by mass, and even more preferably 5 to 20% by mass.

[0038] [Hydrophilic Resin] The composition of the present invention contains a hydrophilic resin. Hydrophilic resins suitable for use in the present invention have a solubility of 5% by mass or more in water, methanol, and ethanol. A solubility of 5% by mass or more improves the affinity with chain silica microparticles and alkoxysilane hydrolysis condensates, resulting in lower film haze and superior appearance. The solubility is preferably 8% by mass or more, and more preferably 10% by mass or more. Examples of hydrophilic resins that can be used in the composition of the present invention include natural polymers, water-soluble resins, and resin emulsions. Specific examples of natural polymers for use in the composition of the present invention include casein, soybean protein, starch, and gelatin.

[0039] Examples of water-soluble resins include resins having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol resin (PVA), cellulose resins (methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC)), chitins, and starch. Resins having an ether bond include polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), and polyvinyl ether (PVE). Resins having an amide group or amide bond include polyacrylamide (PAAM) and polyvinylpyrrolidone (PVP).

[0040] Examples of resin emulsions include conjugated diene polymer emulsions such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer, acrylic polymer emulsions, vinyl polymer emulsions such as ethylene-vinyl acetate copolymer, ester polymer emulsions, urethane polymer emulsions, olefin polymer emulsions, epoxy polymer emulsions, and vinylidene chloride polymer emulsions.

[0041] The hydrophilic resin of the present invention preferably has a hydroxyl group. The presence of a hydroxyl group improves the affinity with chain silica fine particles and alkoxysilane hydrolysis condensates, resulting in a lower haze and a more excellent appearance of the film. Examples of such hydrophilic resins include polyvinyl alcohol resins, cellulose resins (methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), etc.), chitins, and starch.

[0042] The content of hydroxyl groups directly bonded to the main chain of the hydrophilic resin is preferably 35 mol% or less. When the content of the hydroxyl groups is within the above-mentioned range, the film-forming property, flexibility, and dicing property of the film are good. The content of the hydroxyl groups is more preferably 32 mol% or less, more preferably 30.8 mol% or less, and even more preferably 30 mol% or less. On the other hand, the content of the hydroxyl groups is preferably 5 mol% or more, more preferably 10 mol% or more, more preferably 11.6 mol% or more, even more preferably 15 mol% or more, and particularly preferably more than 17.8 mol%. When the content of hydroxyl groups is 5 mol% or more, the haze of the film is low and the appearance is more excellent.

[0043] The content of hydroxyl groups is, for example, １ When the hydrophilic resin is a vinyl alcohol resin, the content of vinyl alcohol structural units (hereinafter, referred to as formula (1)) can be calculated from the degree of saponification, and the hydroxyl group content can be calculated as the proportion of the hydroxyl group in the vinyl alcohol structural units.

[0044] The content of the hydrophilic resin is preferably more than 1 part by mass as a ratio to the total of the silica particles and the alkoxysilane hydrolysis condensate ("mass of hydrophilic resin" / "mass of silica particles + mass of alkoxysilane hydrolysis condensate"). When the content of the hydrophilic resin is within the above-mentioned range, the flexibility and dicing properties of the film are good. The content of the hydrophilic resin is more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, and particularly preferably 2.5 parts by mass or more. The upper limit is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less. When the content of the hydrophilic resin is 30 parts by mass or less, the haze of the film is low and the appearance is more excellent.

[0045] The content of the hydrophilic resin is preferably 5 to 30% by mass as a ratio ("mass of hydrophilic resin" / "mass of chain silica fine particles + mass of alkoxysilane hydrolysis condensate + mass of hydrophilic resin") to the total 100% by mass of the chain silica fine particles, alkoxysilane hydrolysis condensate, and hydrophilic resin. When the content of the hydrophilic resin is 5% by mass or more, the flexibility and dicing ability of the film are good. 8% by mass or more is more preferable, and 10% by mass or more is particularly preferable. On the other hand, when the content is 30% by mass or less, the haze of the film is low and the appearance is more excellent. 25% by mass or less is more preferable, and 20% by mass or less is particularly preferable.

[0046] [Polyvinyl alcohol-based resin] The composition of the present invention can suitably use a polyvinyl alcohol-based resin as the hydrophilic resin. The specific structure of the polyvinyl alcohol-based resin contained in the composition of the present invention is not particularly limited as long as it is a resin having a vinyl alcohol structural unit represented by the following formula (1), and is typically obtained by saponifying a polyvinyl carboxylate obtained by polymerizing a vinyl carboxylate monomer such as vinyl acetate, but is not limited thereto.

[0047]

[0048] Examples of the polyvinyl alcohol resin include unmodified polyvinyl alcohol and modified polyvinyl alcohol. The modified polyvinyl alcohol resin may be a copolymer-modified polyvinyl alcohol resin synthesized by copolymerizing a monomer other than a vinyl ester monomer that provides a polyvinyl alcohol structural unit, or a post-modified polyvinyl alcohol resin obtained by synthesizing unmodified polyvinyl alcohol and then modifying the main chain or side chain with an appropriate compound.

[0049] Examples of copolymerization monomers (unsaturated monomers) that can be used in copolymer-modified polyvinyl alcohol resins include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 5-hexen-1-ol, and derivatives thereof such as acylated products; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid, or salts thereof; monoesters or dialkyl esters; diacetone acrylamide, acrylamide, methacrylic acid, and the like. olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, or salts thereof; quaternary ammonium salts such as diallyldimethylammonium chloride, diallyldiethylammonium bromide; substituted vinyl acetates such as isopropenyl acetate, 1-methoxyvinyl acetate, or the like; allyl ethers having a poly(oxyalkylene) group such as polyethylene glycol allyl ether, methoxypolyethylene glycol allyl ether, polypropylene glycol allyl ether, and polyethylene glycol-polypropylene glycol allyl ether; and the like.

[0050] Copolymer-modified polyvinyl alcohol resins include polyvinyl alcohol resins having primary hydroxyl groups in the side chains, such as side-chain 1,2-diol-modified PVA resins obtained by copolymerizing 3,4-diacetoxy-1-butene, vinyl ethylene carbonate, glycerin monoallyl ether, or the like, and polyvinyl alcohol resins having hydroxymethyl groups in the side chains obtained by copolymerizing and saponifying hydroxymethyl vinylidene diacetates such as 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyronyloxy-2-methylenepropane.

[0051] Methods for post-modifying a post-modified polyvinyl alcohol resin include methods of subjecting unmodified polyvinyl alcohol or the above-mentioned modified polyvinyl alcohol resin to acetoacetic esterification, acetalization, urethanization, etherification, grafting, phosphate esterification, oxyalkylenation, transesterification, etc. From the viewpoint of film flexibility, a polyvinyl alcohol resin modified with caprolactone by transesterification is more preferred.

[0052] The content of vinyl alcohol structural units contained in the polyvinyl alcohol-based resin is preferably 30 to 90 mol%. When the content of vinyl alcohol structural units is 30 mol% or more, the flexibility and bendability of the film are improved, and cracking and peeling during dicing are suppressed. 32 mol% or more is more preferable, 35 mol% or more is even more preferable, and more than 46 mol% is particularly preferable. On the other hand, when the content of vinyl alcohol structural units is 90 mol% or less, dispersibility in organic solvents is good, viscosity increase of the liquid is suppressed, and the appearance of the obtained film is better. 85 mol% or less is more preferable, and 80 mol% or less is particularly preferable.

[0053] The functional group contained in the polyvinyl alcohol resin is preferably an oxyalkylene group, an acetoacetyl group, a carboxyl group, or a sulfoxyl group, and more preferably contains an oxyalkylene group from the viewpoint of film flexibility.

[0054] The average degree of polymerization of the polyvinyl alcohol resin is not particularly limited, but is preferably 200 to 2,000. When the average degree of polymerization is 200 or more, the flexibility and bendability of the film are further improved. On the other hand, when the average degree of polymerization is 2,000 or less, the dispersibility in organic solvents is further improved.

[0055] The content of the polyvinyl alcohol-based resin is preferably more than 1 part by mass relative to a total of 100 parts by mass of the chain silica fine particles and the alkoxysilane hydrolysis condensate. The content of the polyvinyl alcohol-based resin is more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, and particularly preferably 2.5 parts by mass or more. The upper limit is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less. When the content of the hydrophilic resin is 30 parts by mass or less, the haze of the film is low and the appearance is more excellent. When the content of the polyvinyl alcohol-based resin is low, the flexibility and flexibility of the film are further improved, and film cracking during dicing can be suppressed. The content of the polyvinyl alcohol-based resin is more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, and particularly preferably 8 parts by mass or more. On the other hand, when the content is high, the dispersibility in organic solvents is good, the viscosity of the liquid is suppressed, and the appearance of the obtained film is good.

[0056] [Film] The first film of the present invention can be a film obtained using the composition of the present invention. The film obtained by coating the composition of the present invention is generally used as a film formed by coating on a transparent substrate, especially when used for optical purposes. This film is a porous film having a large number of pores. In addition, the surface of the film is preferably smooth, and the unevenness is preferably 5 nm or less, more preferably 3 nm or less, and particularly preferably 2 nm or less.

[0057] The second film of the present invention can be a film containing a hydrophilic resin and having a porosity of 10 to 80%. The second film has excellent dicing properties, low haze, and a low refractive index, making it highly useful industrially. The second film of the present invention can be the same as the first film of the present invention, and the common parts between them will be described together as the film of the present invention.

[0058] <Refractive Index> The refractive index of the film of the present invention is usually 1.15 or more and 1.40 or less, and is appropriately selected depending on the application. When used as an anti-reflection film for glass or plastic substrates, the refractive index is preferably 1.20 or more and 1.35 or less. When forming an anti-reflection film as a single layer, the minimum reflectance can be made as close to 0% as possible by selecting the refractive index of the film according to the refractive index of the substrate. When used as a total reflection film, the refractive index is preferably 1.25 or less, more preferably 1.20 or less, and particularly preferably 1.18 or less. The lower the refractive index, the higher the proportion of light that is totally reflected at the interface between the transparent substrate and the film, which is preferable. However, on the other hand, the porosity of the film increases, which may reduce the mechanical strength of the film.

[0059] <Structure> The structure of the film of the present invention is not particularly limited, and the pores are usually tunnel-shaped or interconnected pores in which independent pores are connected, but the detailed pore structure is also not particularly limited. In addition, by adjusting the pore size and porosity, the refractive index, dielectric constant, and density can be adjusted, and by adjusting these, the film can be used for various purposes other than optical applications. The pore size and porosity can be adjusted by the composition of the film-forming coating liquid and the coating method described below.

[0060] Although there is no particular limitation on the pore size of the film of the present invention, the pore size is usually preferably 0.1 to 50 nm, more preferably 1 to 20 nm, and particularly preferably 2 to 10 nm. If the pore size is too large, it is not suitable for an anti-reflection film formed as a thin film of, for example, about 100 nm, and defects may occur on the surface of the formed film, causing increased surface irregularities and increasing haze due to light scattering, etc. In addition, there is also the problem that the mechanical strength of the film is reduced due to the large number of defects.

[0061] The porosity of the film of the present invention is preferably 10 to 80%, more preferably 10 to 78%, more preferably 20 to 78%, more preferably 30 to 78%, and particularly preferably 30 to 70%. When the porosity is 10% or more, flexibility and optical properties are improved, while when it is 80% or less, mechanical strength, haze, and surface smoothness are improved.

[0062] The pore size of the membrane of the present invention can be measured by analyzing images observed with a transmission electron microscope (TEM) or a scanning electron microscope (SEM). The porosity of the membrane can be calculated from the relationship between the porosity and the refractive index according to the Lorentz-Lorentz equation.

[0063] The thickness of the film of the present invention is preferably 50 to 20,000 nm. The thickness is more preferably 1,000 nm or more, even more preferably 2,000 nm or more, and particularly preferably 3,000 nm or more. A thickness of 50 nm or more exhibits optical effects and also improves mechanical strength. On the other hand, a thickness of 20,000 nm or less makes it easier to uniformize the film structure. A thickness of 19,000 nm or less is more preferable, and 17,000 nm or less is particularly preferable. The thickness can be measured by the method described in the examples below.

[0064] The haze of the film of the present invention is preferably 0 to 3.0%. The haze is more preferably 2.5% or less, even more preferably 2.0% or less, even more preferably 1.8% or less, and particularly preferably 1.0% or less. When the haze is 3.0% or less, the optical properties are better. The lower limit is most preferably 0%. The haze can be measured by the method described in the examples below.

[0065] [Membrane Manufacturing Method] An example of the membrane manufacturing method of the present invention will be described below, but the membrane manufacturing method of the present invention is not limited to the following method.

[0066] To form the film of the present invention, a coating liquid for forming the film (corresponding to the composition of the present invention; hereinafter also referred to as "film-forming coating liquid") is applied to a substrate, and the resulting wet film is then heated, dried, and cured.

[0067] The film-forming coating solution is produced, for example, by adding chain silica particles and a hydrophilic resin to a silicate oligomer containing an alkoxysilane hydrolysis condensate. The solution may also contain a solvent as appropriate.

[0068] (Method for producing a film-forming coating liquid) A film-forming coating liquid is produced by mixing a silicate oligomer containing an alkoxysilane hydrolysis condensate, chain silica fine particles, and a hydrophilic resin. The film-forming coating liquid is adjusted to an appropriate concentration taking into consideration the coatability when applied to a substrate, the film thickness and smoothness of the coating film, etc. The concentration is adjusted by adding the aforementioned hydrophilic solvent, and this concentration adjustment can be performed before or after mixing the chain silica fine particles.

[0069] The chain silica microparticle concentration in the film-forming coating liquid is preferably 30% by mass or less, more preferably 25% by mass or less, particularly preferably 20% by mass or less, and most preferably 17% by mass or less. When the chain silica microparticle concentration is 30% by mass or less, the coating property is further improved and a film with surface smoothness is formed. On the other hand, from the viewpoint of film formation efficiency, the chain silica microparticle concentration in the film-forming coating liquid is preferably 1% by mass or more, more preferably 5% by mass or more.

[0070] In addition, the mixing ratio of silicate oligomer containing alkoxysilane hydrolysis condensate and chain silica microparticles is not particularly limited, as long as it does not block the pores of the film when the obtained film-forming coating solution is used to form the film.If the ratio of silicate oligomer is too high, it is difficult to form pores during film formation, so it is difficult to form the porous film with excellent optical performance, which is the original purpose.On the other hand, if the content of silicate oligomer is too low, the bond between chain silica microparticles is weak, so the mechanical strength is insufficient and the adhesion to the substrate is low, so it may be damaged or peeled off depending on the post-process or use environment.

[0071] From this viewpoint, when mixing a silicate oligomer containing an alkoxysilane hydrolysis condensate with chain silica fine particles, the mixing ratio of the chain silica fine particles to the alkoxysilane hydrolysis condensate is preferably chain silica fine particles:alkoxysilane hydrolysis condensate = 1:0.01 to 2 (mass ratio), and particularly preferably 1:0.05 to 1 (mass ratio).

[0072] The content of the hydrophilic resin in the film-forming coating liquid is preferably 0.05% by mass or more, more preferably 0.1% by mass or more. When the content is 0.05% by mass or more, the flexibility and bendability of the film are further improved. On the other hand, it is preferably 10% by mass or less, more preferably 5% by mass or less. When the content is 10% by mass or less, the viscosity of the liquid is suppressed, and the appearance of the obtained film is improved.

[0073] The solvent contained in the film-forming coating liquid is water and / or an organic solvent. The solvent preferably contains a hydrophilic solvent, and the hydrophilic solvent is not particularly limited, but generally, alcohols such as methanol, ethanol, propanol, butanol, cellosolves such as ethyl cellosolve, butyl cellosolve, propyl cellosolves, glycols such as ethylene glycol, propylene glycol, hexylene glycol, etc. are used. These solvents may be used alone or in combination of two or more. These solvents may be derived from the dispersions of the respective raw materials, or may be mixed when preparing the film-forming coating liquid.

[0074] [Laminate] A film made of the composition of the present invention can be laminated on a substrate to form a laminate. Transparent substrates such as glass and plastics are used as the substrate to be laminated with the film. The transparent substrate has high light transmittance at a specific wavelength and is appropriately selected depending on the application using ultraviolet light, visible light, or infrared light. The specific wavelength is not limited to the visible light range, but in applications such as lenses, optical devices such as displays, solar cells, and solar thermal power generation, building materials, and anti-reflection film applications for the interior and exterior of automobiles, it is preferable that the transparent substrate has high transmittance for light with wavelengths in the visible light range. Usually, a substrate with a total light transmittance of 60% or more is used.

[0075] There are no particular limitations on the thickness or shape of the substrate, and the substrate may have scattering or haze, and may have fine irregularities on its surface, as long as they do not affect the performance of the film.

[0076] Examples of plastics that can be used to form the substrate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), polymethyl methacrylate (PMMA), and cycloolefin polymer (COP).

[0077] The substrate surface may be either surface-modified or unmodified.

[0078] (Coating Method) The method for laminating a film on a substrate is preferably a coating method, and examples of such coating methods include dip coating, spin coating, die coating, spray coating, gravure coating, roll coating, curtain coating, screen printing, and inkjet printing.

[0079] (Drying and Curing Method) The wet film formed by applying the film-forming coating liquid to the substrate is dried to remove the solvent, and the drying temperature is usually 50 to 80° C., and a hot air dryer or the like is suitably used. The drying time is usually 1 to 10 minutes, and preferably 1 to 5 minutes.

[0080] Furthermore, when the transparent substrate is made of plastic, a method of curing the above-mentioned film after drying by irradiating it with ultraviolet light in the presence of oxygen is recommended to impart adhesion. Ultraviolet light includes near ultraviolet light (near UV, wavelength 200-380 nm), far ultraviolet light (far UV, wavelength 10-200 nm), and extreme ultraviolet light (extreme UV, wavelength 1-10 nm), with far ultraviolet light typically being more effective. Examples of ultraviolet light sources include low-pressure mercury lamps, high-pressure mercury lamps, excimer ultraviolet (excimer UV) lamps, halide lamps, and lasers. The ultraviolet light irradiation time is typically 1 second to 3 minutes. Furthermore, when the transparent substrate is made of glass or the like, the curing temperature is 80°C to 150°C, and a hot air dryer or the like is preferably used. The curing time is typically 1 minute to 60 minutes, preferably 1 minute to 30 minutes.

[0081] [Optical Member] The optical member of the present invention may include the laminate of the present invention. The laminate itself may be used as an optical member, or the laminate may be used as a part of an optical member. Examples of the optical member of the present invention include a diffractive optical element (DOE), a cladding material such as an optical fiber, an optical waveguide, an optical display, an AR glass, a camera lens, a medical lens, a microlens, and a LiDAR.

[0082] The film of the present invention can be suitably used as an anti-reflection film, etc. The film of the present invention can be suitably used for displays, automobile panels, lighting fixtures, solar energy devices, camera lenses, face shields, eyeglasses, optical waveguides, etc. For optical applications, the film can be suitably used for diffractive optical elements (DOEs), cladding materials for optical fibers, optical waveguides, optical displays, AR glasses, camera lenses, medical lenses, microlenses, LiDAR, etc. Furthermore, the film can be suitably used as a component for improving the color and brightness of displays.

[0083] The present invention will be described in detail below with reference to examples, but the present invention can be modified appropriately within the scope of the invention and is not limited to the following examples.

[0084] In the examples, various physical properties were measured according to the following methods.

[0085] [Average Primary Particle Diameter of Silica Fine Particles] The average primary particle diameter of silica fine particles was calculated by the BET method.

[0086] [Refractive Index, Film Thickness] The refractive index and film thickness of the porous silicon oxide film laminate (1) were calculated from the reflectance spectrum obtained by an "Interferometric Film Thickness Measuring Instrument F20" manufactured by Filmetrics.

[0087] [Porosity] The porosity of the porous silicon oxide film laminate (1) was calculated using the relationship between porosity and refractive index according to the Lorentz-Lorentz equation. The value of 1.46 was used as the refractive index of the silica fine particles. (Lorentz-Lorentz equation) Porosity (%) = (refractive index of silica fine particles - refractive index of porous silicon oxide film) / 0.46

[0088] [Haze] The porous silicon oxide film laminate (2) was measured at room temperature using a spectrocolorimeter / haze meter ("COH7700" manufactured by Nippon Denshoku Industries Co., Ltd.).

[0089] [Film Formability] The film formability during thin film production was evaluated according to the following criteria: ◯: A uniform film having a thickness of 2.0 μm or more can be produced without any problems. ×: A film having a thickness of 2.0 μm or more cannot be produced.

[0090] [Dicing properties] The porous silicon oxide film laminate (2) was cut from the glass side at room temperature using a cutter equipped with a diamond cutting wheel (Qcut150A manufactured by QATM). The cut cross section was observed with an FE-SEM (JEOL Ltd., JSM-7900F), and the cut film surface was observed with a laser microscope (Keyence Corporation, VK-9700), and evaluated according to the following criteria. (Cracks) ○: No film cracks observed in cross-sectional observation. ×: Film cracks observed in cross-sectional observation. (Peeling evaluation method 1) ○: No film peeling observed in surface observation. ×: Film peeling observed in surface observation. (Peeling evaluation method 2) The porous silicon oxide film laminate (2) was left at room temperature and scratched from the glass side with a diamond cutter, and the film was manually broken along the scratch by applying equal force to both sides of the scratch. The film surface was observed with a laser microscope (Keyence Corporation, "VK-9700") and evaluated according to the following criteria: ◯: No film peeling was observed on the surface. Δ: Partial film peeling was observed on the surface. ×: Overall film peeling was observed on the surface.

[0091] [Flexibility] The porous silicon oxide film laminate (3) was placed at room temperature and wrapped around a cylindrical metal rod with a diameter of 1 mm with the coating surface facing up, and the condition of the test piece was observed and evaluated according to the following criteria: ○: No cracks or peeling in the film. ×: Cracks occurred in the film and the wrapped portion peeled off.

[0092] [Production Example 1] Production of silicate oligomer (A) containing alkoxysilane hydrolysis condensate (1) Hydrolysis reaction step: 5 parts by mass of "KBM22" (dimethyldimethoxysilane content 99% by mass) manufactured by Shin-Etsu Silicones Co., Ltd., 20 parts by mass of "Silicate MS51" (average degree of polymerization n: 7, methyl silicate oligomer content 99.8% by mass) manufactured by Mitsubishi Chemical Corporation, and 50 parts by mass of ethanol were charged into a 500 mL jacketed reactor. The upper limit reaction temperature was set to 40°C, and 33 parts by mass of a 0.007% by mass aqueous hydrochloric acid solution was added dropwise over 10 minutes under stirring conditions. During this time, an exothermic reaction occurred, raising the reaction temperature by 5 to 10°C. Stirring was continued until the reaction temperature had decreased by 5 to 10°C. The proportion of the hydrolyzable silane compound multimer in the total of the bifunctional hydrolyzable silane compound and the hydrolyzable silane compound multimer (the proportion of "Silicate MS51" to the total amount of "KBM22" and "Silicate MS51") was 80 mass%.

[0093] (2) Condensation reaction step: After the hydrochloric acid aqueous solution was added dropwise, the mixture was heated to 60° C. over 30 minutes under stirring conditions, and then maintained at 60° C. for 30 minutes. Thereafter, the mixture was cooled to room temperature.

[0094] (3) Condensation reaction termination step: After cooling, 108 parts by mass of ethanol was added and stirred for 30 minutes to obtain 216 parts by mass of silicate oligomer (A) containing an alkoxysilane hydrolysis condensate. The silicate oligomer (A) containing an alkoxysilane hydrolysis condensate had an alkoxysilane hydrolysis condensate concentration of 15% and a weight average molecular weight of 1,949.

[0095] [Production Example 2] Production of silicate oligomer (B) containing alkoxysilane hydrolysis condensate 50 parts by mass of ethanol was added to 100 parts by mass of silicate oligomer (A) containing alkoxysilane hydrolysis condensate, and the mixture was stirred for 30 minutes to obtain 150 parts by mass of silicate oligomer (B) containing alkoxysilane hydrolysis condensate.

[0096] [Production Example 3] Production of coating liquid (C) for forming a porous silicon oxide film 97 parts by mass of chain silica fine particles ("Snowtex OUP" product manufactured by Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 15 mass%) and 268 parts by mass of chain silica fine particles ("Organosilicasol MEK-ST-UP" product manufactured by Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 20 mass%) were added to 150 parts by mass of silicate oligomer (B) containing an alkoxysilane hydrolysis condensate, and the mixture was stirred for 30 minutes to obtain 515 parts by mass of coating liquid (C) for forming a porous silicon oxide film.

[0097] Example 1 3.75 parts by mass of oxyalkylene group-modified polyvinyl alcohol ("Gohsenex LW-100" product manufactured by Mitsubishi Chemical Corporation, concentration 40% by mass, saponification degree 39 to 46 mol%, polymerization degree 200) was added to 100 parts by mass of the coating liquid (C) for forming a porous silicon oxide film, and the mixture was stirred for 30 minutes to produce 103.75 parts by mass of the coating liquid (D) for forming a porous silicon oxide film of the present invention, which was then evaluated. The results are shown in Table 1.

[0098] Example 2 107.50 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 1, except that the amount of oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-100, manufactured by Mitsubishi Chemical Corporation, concentration 40% by mass, saponification degree 39 to 46 mol%, degree of polymerization 200) added was changed to 7.50 parts by mass. The results are shown in Table 1.

[0099] Example 3 107.50 parts by mass of a porous silicon oxide film-forming coating solution (D) was produced and evaluated in the same manner as in Example 1, except that 7.50 parts by mass of a CL-modified PVOH (Gohsenol NM-11Q, manufactured by Mitsubishi Chemical Corporation, saponification degree 99.1 mol%, degree of polymerization 1,200, which was prepared by modifying 52 mol% with caprolactone in the presence of Lewis acid and diluting the result with ethanol to 10 wt %) was used instead of the oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-100, manufactured by Mitsubishi Chemical Corporation, concentration 40 mass%, degree of saponification 39 to 46 mol%, degree of polymerization 200). The results are shown in Table 1.

[0100] Example 4 115.00 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 1, except that 15.00 parts by mass of a CL-modified PVOH (Gohsenol NM-11Q, manufactured by Mitsubishi Chemical Corporation (saponification degree 99.1 mol%, degree of polymerization 1200) was used instead of the oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-100, manufactured by Mitsubishi Chemical Corporation, concentration 40 mass%, degree of saponification 39 to 46 mol%, degree of polymerization 200), which was obtained by modifying 52 mol% of the PVOH with caprolactone in the presence of a Lewis acid and diluting the resulting solution with ethanol to 10 wt %). The results are shown in Table 1.

[0101] Example 5 103.75 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 1, except that 3.75 parts by mass of an oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-200, a product of Mitsubishi Chemical Corporation, concentration 40% by mass, degree of saponification 39-46 mol%, degree of polymerization 200) was used instead of the oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-100, a product of Mitsubishi Chemical Corporation, concentration 40% by mass, degree of saponification 46-53 mol%, degree of polymerization 200). The results are shown in Table 1.

[0102] Example 6 104.50 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 1, except that 4.50 parts by mass of polyvinyl alcohol (Gohsenol NK-05R, a product of Mitsubishi Chemical Corporation, concentration 10% by mass, saponification degree 71 to 75% by mol, degree of polymerization 500) was used instead of the oxyalkylene group-modified polyvinyl alcohol (Gohsenex LW-100, a product of Mitsubishi Chemical Corporation, concentration 40% by mass, degree of saponification 46 to 53% by mol, degree of polymerization 200). The results are shown in Table 1.

[0103] Example 7 107.50 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 5, except that 7.50 parts by mass of polyvinyl alcohol ("GOHSENOL NK-05R" manufactured by Mitsubishi Chemical Corporation, concentration 10% by mass, saponification degree 71 to 75 mol%, degree of polymerization 500) was used. The results are shown in Table 1.

[0104] Example 8 115.00 parts by mass of a coating solution (D) for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 5, except that 15.00 parts by mass of polyvinyl alcohol (Gohsenol NK-05R, a product of Mitsubishi Chemical Corporation, concentration 10% by mass, saponification degree 71 to 75 mol%, degree of polymerization 500) was used. The results are shown in Table 1.

[0105] Comparative Example 1 A coating solution for forming a porous silicon oxide film was produced and evaluated in the same manner as in Example 1, except that no oxyalkylene group-modified polyvinyl alcohol was added to the coating solution for forming a porous silicon oxide film (C) in Example 1. The results are shown in Table 1.

[0106] Comparative Example 2 A coating fluid for forming a porous silicon oxide film was produced and evaluated in the same manner as in Comparative Example 1, except that 340.75 parts by mass of spherical silica fine particles ("Snowtex OS" product manufactured by Nissan Chemical Industries, Ltd., average primary particle diameter: 9 nm, silica fine particle concentration: 20% by mass) diluted with 24.25 parts by mass of ethanol was used in place of 97 parts by mass of chain silica fine particles ("Snowtex OUP" product manufactured by Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 15% by mass) and 268 parts by mass of chain silica fine particles ("Organosilicasol MEK-ST-UP" product manufactured by Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 20% by mass). The results are shown in Table 1. Comparative Example 2 had problems with film-forming properties and the like, and the refractive index and porosity values ​​could not be clearly determined, so they are marked as "unmeasured" in Table 1.

[0107] Comparative Example 3 A coating solution (E) for forming a porous silicon oxide film was produced in the same manner as in Production Example 3, except that 340.75 parts by mass of spherical silica fine particles ("Snowtex OS" product of Nissan Chemical Industries, Ltd., average primary particle diameter: 9 nm, silica fine particle concentration: 20 mass%) diluted with 24.25 parts by mass of ethanol was used in place of 97 parts by mass of chain silica fine particles ("Snowtex OUP" product of Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 15 mass%) and 268 parts by mass of chain silica fine particles ("Organosilicasol MEK-ST-UP" product of Nissan Chemical Industries, Ltd., average primary particle diameter: 12 nm, average length: 40 to 100 nm, silica fine particle concentration: 20 mass%). Next, a porous silicon oxide film-forming coating liquid was produced and evaluated in the same manner as in Example 6, except that the porous silicon oxide film-forming coating liquid (E) was used instead of the porous silicon oxide film-forming coating liquid (C). The results are shown in Table 1.

[0108] [Preparation of Porous Silicon Oxide Film Laminate (1) (for Refractive Index and Porosity Evaluation)] A 6-inch Si wafer (manufactured by Advanced Materials Technology Co., Ltd.) was cut to a size of 2 cm, and the porous silicon oxide film-forming coating liquid obtained above was dropped onto it. A thin film was produced by coating for 30 seconds at 3,500 rpm using a spin coater (manufactured by Mikasa Co., Ltd., "MS-A150") The solvent was then removed, and the wafer was placed in a low-temperature thermostatic blower (manufactured by Yamato Scientific Co., Ltd.) for thermal curing, and dried at 120°C for 10 minutes to obtain a 3.5 μm-thick laminate (1) of a porous silicon oxide film and a Si wafer. The refractive index and porosity of the obtained porous silicon oxide laminate (1) were measured. The evaluation results are shown in Table 1.

[0109] [Preparation of porous silicon oxide film laminate (2) (for dicing and haze evaluation)] The porous silicon oxide film-forming coating liquid obtained above was dropped onto a 1 mm thick slide glass plate ("S9111" manufactured by Matsunami Glass Co., Ltd.) and coated with a spin coater ("MS-A150" manufactured by Mikasa Co., Ltd.) at 2000 rpm for 30 seconds to produce a thin film. Thereafter, the solvent was removed, and the film was placed in a low-temperature constant-temperature blower (manufactured by Yamato Scientific Co., Ltd.) for thermal curing and dried at 120 ° C. for 10 minutes to obtain a laminate (2) of a porous silicon oxide film and a glass plate having a thickness of 4.5 μm. The dicing property and haze were evaluated using the obtained porous silicon oxide laminate (2). The obtained evaluation results are shown in Table 1.

[0110] [Preparation of porous silicon oxide film laminate (3) (for flexibility evaluation)] The porous silicon oxide film-forming coating solution obtained above was dropped onto a 0.3 mm thick acrylic sheet ("Technoloy S000" manufactured by Sumika Acrylic Sales Co., Ltd.) and coated for 30 seconds at 2000 rpm using a spin coater ("MS-A150" manufactured by Mikasa Co., Ltd.) to produce a thin film. Thereafter, the solvent was removed, and the film was placed in a low-temperature constant-temperature blower (manufactured by Yamato Scientific Co., Ltd.) for thermal curing and dried at 70 ° C. for 10 minutes to obtain a 4.5 μm thick laminate (3) of a porous silicon oxide film and an acrylic sheet. The flexibility of the obtained porous silicon oxide laminate (3) was evaluated. The evaluation results are shown in Table 1.

[0111]

[0112] The results of this example demonstrate that films and laminates made from the compositions of the present invention described in Examples 1 to 8 have excellent flexibility and can suppress film cracking and peeling during dicing. Furthermore, the films had low refractive index and haze, and were excellent in optical properties. The film of Comparative Example 1, which did not contain a hydrophilic resin in the composition, had insufficient flexibility and cracked and peeled during dicing. The film of Comparative Example 2 used spherical silica microparticles instead of chain silica microparticles and did not contain a hydrophilic resin, and was therefore inferior in film-forming properties, flexibility, and dicing properties. Furthermore, the film had high haze and was also inferior in optical properties. Comparative Example 3 used spherical silica microparticles instead of chain silica microparticles, and was therefore inferior in film-forming properties, flexibility, and dicing properties. Furthermore, the film had high haze and was also inferior in optical properties. Furthermore, the film had high haze and refractive index, and was also inferior in optical properties. Furthermore, the porosity was low.

[0113] The porous silicon oxide film and laminate made of the composition of the present invention are highly flexible and can suppress cracking and peeling during dicing, and therefore can be suitably used for optical components such as diffractive optical elements (DOEs), cladding materials for optical fibers, optical waveguides, optical films, AR glasses, camera lenses, medical lenses, microlenses, LiDAR, etc. In particular, they are effectively applicable to applications requiring miniaturization and tracking ability of parts.

Claims

1. A composition comprising chain-like silica fine particles, an alkoxysilane hydrolysis condensate, and a hydrophilic resin.

2. The composition according to claim 1 , wherein the hydrophilic resin has a hydroxyl group.

3. 3. The composition according to claim 1, wherein the content of hydroxyl groups directly bonded to the main chain of the hydrophilic resin is 35 mol % or less.

4. 4. The composition according to claim 1, wherein the content of the hydrophilic resin is more than 1 part by mass per 100 parts by mass of the chain silica fine particles and the alkoxysilane hydrolysis condensate combined.

5. 5. The composition according to claim 1, wherein the content of the alkoxysilane hydrolysis condensate is 5 to 30% by mass, relative to 100% by mass of the total of the chain silica fine particles, the alkoxysilane hydrolysis condensate, and the hydrophilic resin.

6. 6. The composition according to claim 1, wherein the content of the chain silica fine particles is 60 to 90% by mass, relative to 100% by mass of the total of the chain silica fine particles, the alkoxysilane hydrolysis condensate, and the hydrophilic resin.

7. 7. The composition according to claim 1, wherein the alkoxysilane hydrolysis condensate has a weight average molecular weight of 1,000 to 5,000.

8. 8. The composition according to claim 1, wherein the chain silica fine particles have an average primary particle size of 5 to 100 nm.

9. 9. The composition according to claim 1, wherein the hydrophilic resin has an average degree of polymerization of 200 to 2,000.

10. A film comprising the composition according to any one of claims 1 to 9.

11. A membrane containing a hydrophilic resin and having a porosity of 10 to 80%.

12. The film according to claim 10 or 11, having a thickness of 1,000 nm to 20,000 nm.

13. 13. The membrane according to claim 10 or 12, wherein the porosity of the membrane is 10 to 80%.

14. The film according to any one of claims 10 to 13, having a refractive index of 1.15 to 1.

40.

15. The membrane according to any one of claims 10 to 14, wherein the pore size of the membrane is from 0.1 to 50 nm.

16. A laminate comprising the film according to any one of claims 10 to 15 and a substrate.

17. 17. The laminate of claim 16, wherein the substrate is glass or plastic.

18. An optical element comprising the laminate of claim 17.