JP6933032B2 - Silicon oxide thin film laminated transparent material - Google Patents

Description

The present invention relates to a silicon oxide thin film laminated transparent body, and more particularly to a silicon oxide thin film laminated transparent body formed by laminating a porous silicon oxide thin film on the surface of a plastic base material.

As a method for forming the silicon oxide thin film, for example, the following methods by a physical vapor deposition method (ordinary vacuum deposition, ion plating, sputtering method) and a method using a hydrolyzable silane compound are known.

_{A thin film which is an antireflection film (SiO 2} etc.) is formed on an aromatic polycarbonate resin molded product by vapor deposition, and the film thickness is 1 to 300 nm, and the adhesion defined below is 80% or more. Molded body with film (Patent Document 1).
Adhesion: 100 grids at 1 mm intervals were made on the vapor-deposited surface of the molded plate with a cutter knife, Nichiban adhesive tape (trade name "Cellotape") was crimped, and then the adhered cellophane tape was peeled off at a right angle and rapidly. Percentage (%) of the number of grids that remained without peeling.

The silicon compound is hydrolyzed by mixing (1) silica fine particles, (2) hydrolyzable silane compound, water, and a binder solution containing the hydrolysis catalyst and solvent of the silicon compound to hydrolyze the silicon compound, and then (3) silanol. A method of coating a resin base material with a low-reflection layer liquid obtained by adding a curing catalyst that promotes condensation of groups, and react-curing at a predetermined temperature to form a low-reflection layer containing silica fine particles and a binder (Patented). Document 2).

Japanese Patent No. 4700379 International Publication No. 2004/070436 Pamphlet

The characteristics of the silicon oxide thin film differ greatly depending on the formation method. The silicon oxide thin film obtained by the physical vapor deposition method is dense and has a refractive index of about 1.46, whereas a hydrolyzable silane compound is used. The resulting silicon oxide thin film is porous and has a refractive index of 1.16 to 1.42, which varies depending on the specific method.

By the way, the refractive index of a highly transparent resin is usually 1.49 to 1.78, so if a silicon oxide thin film having the above characteristics obtained by using a hydrolyzable silane compound is formed on the surface thereof, It is useful as a functional base material such as an antireflection film and a low reflection film.

However, when a silicon oxide thin film is formed on the surface of a resin base material by using a hydrolyzable silane compound, there is a problem that the adhesion to the resin base material is not sufficient. In fact, in the case of the above-mentioned proposed method, the adhesion test of the measurement method based on the grid test JIS K5400 (the method of sticking the cellophane tape manufactured by Nichiban Co., Ltd. on the coating and then peeling it off vigorously). The result is "whole peeling".

The present invention has been made in view of the above circumstances, and an object of the present invention is to laminate a porous silicon oxide thin film on the surface of a plastic base material, and to laminate a silicon oxide thin film having excellent adhesion to the base material. It is to provide a transparent body.

As a result of diligent studies on a silicon oxide thin film formed by using a hydrolyzable silane compound in order to achieve the above-mentioned problems, the present inventors have obtained the following findings.

That is, the binder in the above method has an action of acting between the silica particles to form a silicon oxide thin film and an action of adhering the silicon oxide thin film to the surface of the base material, and the action is obtained by the difference in the preparation method. The ideal binder is a reaction composition having a large amount of −OH groups and rich in a linear structure, which varies greatly depending on the properties of the reaction composition to be obtained. Then, if such an ideal binder is used, the adhesion of the silicon oxide thin film to the substrate can be remarkably improved.

The present invention has been completed based on the above findings, and the gist thereof is defined below by laminating a porous silicon oxide thin film having a refractive index of 1.16 to 1.42 on the surface of a plastic base material. A silicon oxide thin film laminated transparent body having an adhesion of 80% or more of a porous silicon oxide thin film.
The porous silicon oxide thin film hydrolyzes and condenses a multimer of a bifunctional hydrolyzable silane compound and a hydrolyzed silane compound in the absence of silica particles to obtain a silicate binder solution and silica fine particles. It exists in a silicon oxide thin film laminated transparent body, which is formed by applying a coating liquid for forming a silicon oxide thin film to be contained on a plastic base material, and then drying and curing the mixture.
Adhesion: In accordance with JIS K5600, an adhesiveness test was conducted by the cross-cut method using an industrial 24 mm cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. as an adhesive tape, and the cells that did not peel off with respect to the total number of cells. Obtain the ratio of the number of eyes (membrane residual rate). However, the interval between cuts is 5 mm, and the number of squares is 25. However, the adhesion of the porous silicon oxide thin film is determined after the durability of the silicon oxide thin film laminated transparent material is evaluated by holding it in an environmental tester set in an environment of a temperature of 60 ° C. and a relative humidity of 95% for 30 minutes. Perform the above-mentioned adhesion test for the state of reduced adhesion.

Hereinafter, the present invention will be described in detail.

The plastic base material may be a film (100 μm or less) or a thicker sheet. Incidentally, examples of plastics include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), polymethylmethacrylate (PMMA), cycloolefin polymer (COP) and the like. The surface of the base material can be applied to either a surface-modified surface or an untreated surface.

The porous silicon oxide thin film having a refractive index of 1.16 to 1.42 can be laminated on the surface of the plastic substrate by a method using a hydrolyzable silane compound.

In the method using a hydrolyzable silane compound, a binder solution composed of a reaction composition obtained by hydrolyzing and condensing the hydrolyzable silane compound is used.

In the preparation of the binder solution, a hydrolyzable silane compound composed of a bifunctional hydrolyzable silane compound and in which at least 50% by weight is a multimer is used, and the hydrolyzable silane compound is prepared in the absence of silica particles. It is preferable to carry out the above reaction by continuously dropping an acid catalyst aqueous solution into the dissolved hydrophilic solvent solution under stirring conditions.

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 ketooxime group, an isocyanate group and a halogen atom.

Among the above, an alkoxysilane compound is preferably used. Examples of the alkyl group of the alkoxy group (−OR) include lower alkyl groups such as a methyl group, an ethyl group, a propyl group and a butyl group. Depending on the number of hydrolyzable groups, those having 1 to 4 functionalities are known.

Typical examples of alkoxysilane compounds are dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS), tetramethoxysilane (TMS), dimethyldiethoxysilane (DMDES), methyltriethoxysilane (MTES), and tetraethoxysilane. (TEOS) and the like.

The multimer of the hydrolyzable silane compound is a multimerized polymer (oligomerized) of the above-mentioned monomers by condensation. In this reaction, first, a silanol group (-Si-OH) is formed by hydrolysis of the alkoxy group. At the same time, alcohol (R-OH) is produced. Next, a siloxane bond (-Si-O-Si-O-) is formed by (dehydration) condensation of silanol groups, and this condensation is repeated to form a siloxane oligomer. As the multimer of the alkoxysilane compound, a multimer of tetramethoxysilane in which R is a methyl group or a multimer of tetraethoxysilane in which R is an ethyl group is preferable from the viewpoint of hydrolyzability and condensability of the alkoxy group. ..

The structure of the multimer includes a linear structure, a branched structure, a cyclic structure, and a network structure. If the multimer of tetraalkoxysilane is shown as having a linear structure, it is represented by the following general formula. ..
[Chemical 1]
RO (Si (OR) ₂ O) _n R ... (I)

In the general formula, n represents the degree of quantification of the multimer. Usually available multimers are compositions of multimers with different n and therefore have a molecular weight distribution. The degree of quantification is represented by an average of n.

The degree of quantification of a tetrafunctional hydrolyzable silane compound such as tetraalkoxysilane or a multimer thereof may be expressed by "silica content". _{The "silica content" is the mass ratio of silica (SiO 2} ) produced from the compound, and is obtained by measuring the amount of silica produced by stably hydrolyzing the compound and firing it. Further, "silica content" also indicates the ratio of silica produced to one molecule of the compound, and is a value calculated by the following formula.
[Number 1]
Silica content (parts by mass) = degree of _{quantification x molecular weight of SiO 2} / molecular weight of the compound

The degree of quantification n is usually 2 to 100, preferably 2 to 70, and more preferably 2 to 50. Since such a multimer is already on the market, it is convenient to use it. As the degree of quantification n increases, the molecular weight of the produced binder increases and the molecular weight distribution becomes wider. Therefore, a multimer having a degree of quantification n exceeding 100 is inappropriate.

Commercially available products of hydrolyzable silane compound multimers include MKC silicate MS51, MKC silicate MS56, MKC silicate MS57, MKC silicate MS56S (all are tetramethoxysilane multimers) manufactured by Mitsubishi Chemical Co., Ltd., and methyl manufactured by Corcote. Examples thereof include silicate 51 (multimer of tetramethoxysilane), methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, ethyl silicate 40 manufactured by Tama Chemical Industry Co., Ltd., and silicate 45 (all of which are multimers of tetraethoxysilane).

The proportion of multimers in the bifunctional hydrolyzable silane compound is preferably 70% by weight or more. When the amount of the multimer used is small, the hydrolysis and condensation reaction of the monomer reduces the number of OH groups and increases the number of branched, cyclic, and network structures in the reaction composition.

The hydrolysis and condensation reactions are carried out sequentially, and if silica particles are present in the reaction process (by heating), each component generated during the reaction is adsorbed on the surface of the silica particles. This adsorption is a strong state in which the OH groups of the binder component and the OH groups of the silica particles are hydrogen-bonded or siloxane bonds are formed, and the OH groups that contribute to the adhesion of the binder to the substrate and the increase in the strength of the silicon oxide thin film are present. It will decrease. In addition, the binder component adsorbed on the silica particles serves as a cross-linking point, which increases the branched structure and the network structure. On the other hand, the reaction product prepared in the absence of silica particles is rich in a linear structure having a large amount of OH groups. Therefore, a binder liquid is prepared in the absence of silica particles, and the obtained binder liquid and silica fine particles are mixed at room temperature to prepare a coating liquid for forming a silicon oxide thin film.

The above reaction is carried out by continuously dropping an acid catalyst aqueous solution into a hydrophilic solvent solution in which a hydrolyzable silane compound is dissolved under stirring conditions.

The hydrophilic solvent is not particularly limited as long as it can dissolve a multimer of the hydrolyzable silane compound, but is generally limited to alcohols such as methanol, ethanol, propanol and butanol, ethyl cellosolve, butyl cellosolve and propyl cellosolve. Cellulosolves such as, ethylene glycol, propylene glycol, glycols such as hexane glycol are used.

The amount of the hydrophilic solvent used is not particularly limited, but is a ratio to 100 parts by weight of the hydrolyzable silane compound in consideration of the coatability of the coating liquid for forming a silicon oxide thin film prepared by mixing silica fine particles with the binder liquid. It is usually 0.1 to 100 times by weight, preferably 1 to 10 times by weight. Incidentally, the multimer of the hydrolyzable silane compound is a composition composed of components having different degrees of polymerization as described above, and the viscosity increases as the degree of polymerization increases. On the other hand, a commercially available product of the monomer, for example, dimethyldimethoxysilane, is usually a solution having a purity of 99% by weight.

The acid concentration in the acid catalyst aqueous solution is usually in the range of 0.1 to 0.0001% by weight, preferably 0.01 to 0.001% by weight. When the acid catalyst is used as such a low-concentration aqueous solution, a large amount of water is involved in the reaction system, and as a result, the reaction rate of the condensation reaction, which is a competitive reaction, can be suppressed. Therefore, the tendency is that the OH groups generated by hydrolysis disappear at an appropriate rate, and it becomes easy to obtain a reaction composition rich in a linear structure having a large amount of OH groups.

The amount of the acid catalyst used is usually 0.001 to 10 mmol, preferably 0, based on 100 mol of the total amount of hydrolyzable groups (typically alkoxy groups) of the hydrolyzable silane compound in the hydrophilic solvent solution. It is 0.01 to 10 mmol.

The acid catalyst aqueous solution is continuously added dropwise, and the dropping rate is appropriately selected so that the temperature in the reaction system does not rise sharply. The dropping rate of the acid catalyst aqueous solution is usually 1 to 10 ml / min, preferably 3 to 5 ml / min, per 100 ml of the hydrophilic solvent solution. The dropped catalyst aqueous solution is immediately and uniformly diffused by stirring, and uniform hydrolysis is performed. As the stirring method, the method adopted in a normal chemical reaction can be adopted.

The hydrolysis and condensation reactions of the hydrolyzable silane compound are practically carried out sequentially and in parallel. From the viewpoint of obtaining a reaction composition rich in a linear structure having a large amount of OH groups, the hydrolysis and condensation reactions are carried out separately in the following three steps as much as possible.

(1) Hydrolysis reaction step:
This is done by dropping an acid catalyst aqueous solution into a hydrophilic solvent solution under stirring conditions. The reaction temperature is usually 5 to 50 ° C, preferably 10 to 40 ° C. If the reaction temperature is less than the above range, the hydrolysis reaction becomes too slow, and if it exceeds the above range, it becomes difficult to avoid the condensation reaction. The reaction temperature is controlled by the temperature and circulation amount of the refrigerant conducted on the jacket of the reactor, the dropping speed of the acid catalyst aqueous solution, and the like. When the boiling point of the hydrophilic solvent is low, the hydrolysis reaction is carried out under reflux conditions. The reaction time is usually 1 to 60 minutes, preferably 5 to 30 minutes.

The hydrolysis reaction is an exothermic reaction, and the temperature of the reaction solution usually rises by 1 to 15 ° C. In order to confirm that the hydrolysis reaction is substantially completed, it is preferable to continue stirring until the reaction temperature drops by 5 to 10 ° C. after the completion of dropping the acid catalyst aqueous solution.

(2) Condensation reaction step:
Following the above steps, the reaction temperature is raised as necessary and the reaction is carried out under stirring conditions. The reaction temperature is usually 40 to 80 ° C, preferably 50 to 60 ° C. If the reaction temperature is less than the above range, the condensation reaction becomes too slow, and if it exceeds the above range, it becomes difficult to avoid an excessive condensation reaction. The heating rate is usually 0.1 to 10 ° C./min. The reaction time is usually 1 to 120 minutes, preferably 5 to 60 minutes.

(3) Condensation reaction termination step:
The reaction solution is cooled to stop the condensation reaction. The cooling temperature is usually 10 to 30 ° C. At this time, it is more effective to stop the condensation reaction by cooling dilution with which a hydrophilic solvent is added in order to reduce the concentration of the condensation reaction composition. The hydrophilic solvent is preferably the same as the reaction solvent, but another hydrophilic solvent may be used for adjusting the liquid property.

The amount of the hydrophilic solvent added is usually in the range of 50 to 150% by weight when expressed as the concentration of the hydrophilic solvent with respect to the total amount of the hydrolyzable silane compound, the hydrophilic solvent used for the reaction and the acid catalyst aqueous solution.

According to the above-mentioned step of stopping the condensation reaction by cooling dilution, the storage stability of the obtained binder liquid is improved, and it becomes possible to prepare a binder liquid that can be adjusted to a concentration that meets the requirements of each application.

The weight average molecular weight of the obtained reaction composition is determined by the above-mentioned condensation reaction step. The weight average molecular weight is usually 1000 to 5000, preferably 2000 to 4000. Such a molecular weight corresponds to a multimer having a degree of equalization n of 2 to 100.

The above weight average molecular weight is a value measured by gel permeation chromatography (GPC) under the following conditions.

[Solvent] Tetrahydrofuran [Device name] TOSOH HLC-8220GPC
[Column] Tosoh TSKgel Super HM-N (2) and HZ1000 (1) are connected and used.
[Column temperature] 40 ° C
[Sample concentration] 0.01% by mass
[Flow velocity] 0.6 ml / min
[Calibration curve] PEG (calibration curve with a molecular weight of 20000, 4000, 1000, 200 by 4-point cubic approximation is used.

The binder liquid for forming a silicon oxide thin film composed of the above reaction composition is substantially transparent, and the turbidity is 10 or less as a result of measurement using a kaolin turbidity meter.

The coating liquid for forming a silicon oxide thin film is prepared by mixing the binder liquid obtained above with the silica fine particles.

The silica fine particles are not particularly limited, and are spherical non-aggregated silica fine particles having an average particle diameter of 5 to 100 nm, hollow non-aggregated silica fine particles having an average particle diameter of 10 to 100 nm, and chain aggregate having an average primary particle diameter of 5 to 100 nm. Examples thereof include silica fine particles composed of at least one type of silica fine particles. These are appropriately selected according to the purpose of the silicon oxide thin film to be formed.

Specific examples of spherical non-aggregated silica fine particles include "Snowtex (registered trademark) -O", "Snowtex (registered trademark) -O-40", and "Snowtex (registered trademark)-" manufactured by Nissan Chemical Industries, Ltd. "OL", "Quatron (registered trademark) -PL-1", "Quatron (registered trademark) -PL-3", "Quatron (registered trademark) -PL-7", etc. manufactured by Fuso Chemical Industries, Ltd. can be mentioned.

Specific examples of the chain-aggregated silica fine particles include "Snowtex (registered trademark) -OUP" (average length: 40 to 100 nm) and "Snowtex (registered trademark) -UP" (average) manufactured by Nissan Chemical Industry Co., Ltd. Length: 40-100 nm), "Snowtex® PS-M" (average length: 80-150 nm), "Snowtex® PS-MO" (average length: 80-150 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), "Fine Cataloid F-120" manufactured by Japan Catalytic Chemical Industry Co., Ltd. and the like can be mentioned.

The coating liquid for forming a silicon oxide thin film is prepared at an appropriate concentration in consideration of coatability when applied to a substrate, film thickness and smoothness of the coating film, and the like. The concentration adjustment is performed by adding the above-mentioned hydrophilic solvent, and this concentration adjustment can be performed before or after mixing the silica fine particles.

The silicon oxide thin film is formed by drying and curing after applying the coating liquid.

The application of the coating liquid is not particularly limited, and examples thereof include a dip coating method, a spin coating method, a die coating method, a spray coating method, a gravure coating method, a roll coating method, a curtain coating method, a screen printing method, and an inkjet printing method. can.

The coating film thickness is appropriately selected according to the purpose of the silicon oxide thin film to be formed. It is usually 50 to 5000 nm.

The above drying is performed to remove the solvent, the drying temperature is usually 50 to 80 ° C., and a hot air dryer or the like is preferably used. The drying time is usually 1 to 10 minutes, preferably 1 to 5 minutes.

The above curing treatment is mainly performed to bond the silanol group (Si-OH) contained in the binder solution with an oxygen-containing functional group such as a hydroxyl group or a carboxyl group on the surface of the base material, thereby forming a silicon oxide thin film. Will be done.

As the above curing treatment, a method of irradiating ultraviolet rays in the presence of oxygen is recommended. Ultraviolet rays include near ultraviolet rays (near UV, wavelength 200 to 380 nm), far ultraviolet rays (wavelength 10 to 200 nm), and extreme ultraviolet rays (extreme UV, wavelength 1 to 10 nm), but far ultraviolet rays are usually effective. Examples of the ultraviolet source include a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer ultraviolet (excimer UV) lamp, a halide lamp, and a laser. The irradiation time of ultraviolet rays is usually 1 second to 3 minutes.

In the case of a curing treatment in which a plastic base material is used as a base material and ultraviolet rays are irradiated in the presence of oxygen, a silicon oxide thin film having significantly improved base material adhesion is formed. The reason is presumed as follows.

That is, the surface of the plastic base material is activated (modified) by the active oxygen generated by the action of ultraviolet rays, and the silanol groups (Si—OH) contained in the binder liquid and the surface of the base material are firmly bonded.

Hereinafter, the present invention will be described in more detail than the examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The analysis methods in the following examples are as follows.

Example 1
<Preparation of binder liquid for forming silicon oxide thin film>
(1) Hydrolysis reaction step:
A 2L jacketed reactor, Shin-Etsu Silicone Co., Ltd. Product "KBM22" (dimethyl methoxysilane content 99 wt%) 50 parts by mass, Mitsubishi Chemical Corporation, trade "Silicate MS51" (average multimeric degree n: 7, methyl 200 parts by mass of silicate oligomer content (99.8% by weight) and 500 parts by mass of ethanol were charged, the upper limit reaction temperature was set to 40 ° C., and under stirring conditions, 330 parts by mass of a 0.007% by weight hydrochloric acid aqueous solution was applied over 10 minutes. Dropped. At this time, the reaction temperature increased by 5 to 10 ° C. due to the exothermic reaction. Stirring was continued until the reaction temperature dropped by 5-10 ° C. The ratio of the multimer to the bifunctional hydrolyzable silane compound (the ratio of silicate MS51 to the total amount of "KBM22" and "silicate MS51") is 80% by weight.

(2) Condensation reaction step:
After dropping the aqueous hydrochloric acid solution, the temperature was raised to 60 ° C. over 30 minutes under stirring conditions, and the temperature was maintained at 60 ° C. for 30 minutes. Then, it cooled to room temperature.

(3) Condensation reaction termination step:
After cooling, 1100 parts by mass of ethanol was mixed and stirred for 30 minutes to obtain 2180 parts by mass of the alkoxysilane composition (A).

<Preparation of coating liquid for forming silicon oxide thin film>
12000 parts by mass of ethanol was added to 2180 parts by mass of the alkoxylan composition (A) obtained above, and the mixture was stirred for 30 minutes to obtain 14180 parts of the alkoxysilane composition (B).

A silicon oxide thin film is formed by adding 2040 parts by mass of spherical non-aggregated silica (product "Snowtex O" manufactured by Nissan Chemical Industries, Ltd.) to 14180 parts by mass of the alkoxysilane composition (B) obtained above and stirring for 30 minutes. A coating liquid for forming was obtained.

<Manufacturing of silicon oxide thin film laminated transparent material>
The coating liquid for forming a silicon oxide thin film obtained in Example 1 was dropped onto a polyethylene terephthalate (PET) film (diafoil T600 manufactured by Mitsubishi Chemical Co., Ltd.) having a thickness of 50 μm cut into 52 × 76 mm, and a spin coater (Mikasa) was added. A thin film was prepared by coating with "MS-A150" manufactured by the same company at 1200 rpm for 30 seconds.

Then, in order to remove the solvent, it was placed in a constant temperature and constant temperature blower (manufactured by Yamato Kagaku Co., Ltd.) and dried at 70 ° C. for 1 minute. Next, a silicon oxide thin film laminated PET having a thickness of 100 nm was formed by irradiating ultraviolet rays with ^{an illuminance of 130 mW / cm 2} and an integrated light intensity of 1000 mJ / cm ^{2 in} the atmosphere using a high-pressure mercury lamp (manufactured by Eye Graphics). Obtained.

[Measurement of refractive index of silicon oxide thin film]
The refractive index of the silicon oxide thin film laminated PET obtained above was measured by an optical interferometry film thickness measuring device F20 manufactured by Filmometrics Co., Ltd. In the measurement, in order to suppress reflection from the back surface of the PET substrate, a vinyl tape (black) manufactured by Denka Co., Ltd. was attached to the back surface for measurement.

[Adhesion test method]
Adhesion was evaluated by a cross-cut method using an industrial 24 mm cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. as an adhesive tape in accordance with JIS K5600.
That is, 25 grids at 5 mm intervals were made with a cutter knife, cellophane tape was attached to the surface of the film, and after the film was separated, the number of the remaining film without peeling was counted and evaluated.
Since the silicon oxide thin film has properties similar to those of glass, cracks are likely to occur when making a grid with a cutter knife, and it is difficult to perform an accurate adhesion test. Although it is 1 mm or 2 mm, the interval between the grids has been changed to 5 mm.
The ratio of the number of squares that did not peel off (membrane residual ratio) to the total number of squares (25) was determined. The results are shown in Table 1.

[Moisture resistance test]
The silicon oxide thin film laminated PET prepared in Examples and Comparative Examples was held in an environmental tester (SH-641 manufactured by ESPEC) set in an environment of a temperature of 60 ° C. and a relative humidity of 95% for 30 minutes to evaluate the durability. went. The state of reduced adhesion was evaluated by the above-mentioned adhesion test method. The results are shown in Table 1.

[Scratch resistance test]
The cheesecloth described in MIL-Spec MIL-CCC-C-440 was reciprocated 5 times on the surface of the obtained silicon oxide thin film under a ^{load of 100 g (360 g / cm 2).} The scratch resistance was evaluated by the difference in haze value (%) before and after the scratch test. The smaller the difference in haze value, the better the scratch resistance. A haze value difference of about 0.1% was a state in which scratches could not be visually confirmed.

Comparative Example 1:
In Example 1, the silica used in the step of preparing the coating liquid for forming a silicon oxide thin film was changed to chain silica (product "Snowtex OUP" manufactured by Nissan Chemical Industries, Ltd.), and this was added and hydrolyzed. A step, a condensation reaction step, and a condensation reaction termination step are performed, and after cooling, 1100 parts by mass of ethanol is mixed, stirred for 30 minutes, and then 12000 mass of ethanol used in the preparation step of the coating liquid for forming a silicon oxide thin film. A coating liquid for forming a silicon oxide thin film was prepared in the same manner as in Example 1 except that the portion was added. Then, in the same manner as in Example 1, a silicon oxide thin film laminated PET having a thickness of 100 nm was obtained, and the adhesion of the silicon oxide thin film was evaluated. The results are shown in Table 1.

Comparative Example 2:
In Example 1, the silica used in the step of preparing the coating liquid for forming a silicon oxide thin film was changed to chain silica (product "Snowtex OUP" manufactured by Nissan Chemical Industry Co., Ltd.), and 0.007% by weight was used. A coating liquid for forming a silicon oxide thin film was prepared in the same manner as in Example 1 except that the same amount of pure water was used instead of the aqueous hydrochloric acid solution. Then, in the same manner as in Example 1, a silicon oxide thin film laminated PET having a thickness of 100 nm was obtained, and the adhesion of the silicon oxide thin film was evaluated. The results are shown in Table 1.

Comparative Example 3:
In Example 1, the silica used in the preparation step of the coating liquid for forming a silicon oxide thin film was changed to chain silica (product "Snowtex OUP" manufactured by Nissan Chemical Industries, Ltd.), and 50 parts by mass of "KBM22" was changed. , 200 parts by mass of "Silica MS51" was changed to 150 parts by mass of "KBM22" and 100 parts by mass of "Silica MS51", respectively, and a coating liquid for forming a silicon oxide thin film was prepared in the same manner as in Example 1. .. The proportion of the multimer in the bifunctional hydrolyzable silane compound is 40% by weight. Then, in the same manner as in Example 1, a silicon oxide thin film laminated PET having a thickness of 100 nm was obtained, and the adhesion of the silicon oxide thin film was evaluated. The results are shown in Table 1.

Claims (1)

A porous silicon oxide thin film having a refractive index of 1.16 to 1.42 is laminated on the surface of a plastic base material, and the adhesion of the porous silicon oxide thin film defined below is 80% or more. The body
The porous silicon oxide thin film hydrolyzes and condenses a multimer of a bifunctional hydrolyzable silane compound and a hydrolyzed silane compound in the absence of silica particles to obtain a silicate binder solution and silica fine particles. A silicon oxide thin film laminated transparent body, which is formed by applying a coating liquid for forming a silicon oxide thin film to be contained on a plastic base material, and then drying and curing the mixture.
Adhesion: In accordance with JIS K5600, an adhesiveness test was conducted by the cross-cut method using an industrial 24 mm cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. as an adhesive tape, and the cells that did not peel off with respect to the total number of cells. Obtain the ratio of the number of eyes (membrane residual rate). However, the interval between cuts is 5 mm, and the number of squares is 25. However, the adhesion of the porous silicon oxide thin film is determined after the durability of the silicon oxide thin film laminated transparent material is evaluated by holding it in an environmental tester set in an environment of a temperature of 60 ° C. and a relative humidity of 95% for 30 minutes. The above-mentioned adhesion test is performed for the state of reduced adhesion.