JPH0230767A - Formation of thin oxide film and laminated body - Google Patents

Abstract

PURPOSE:To form a thin metal-oxide film excellent in the adhesive strength of a film by applying an alcohol solution of metal or nonmetal alkoxide in which a mixed solvent of alcohols having a specific composition is used to a base material of organic high polymer. CONSTITUTION:A mixed solvent of <=4C alcohol, such as ethanol, and >=5C alcohol, such as amyl alcohol, is prepared. At this time, the volume percentage of the >=5C alcohol is regulated to 5-70%. Metal or nonmetal alkoxide is dissolved in the above mixed solvent, and further, water and acid are added to the above. The resulting solution is applied to an organic high polymer base material and then the solvent is evaporated, by which a thin oxide film of metal or nonmetal is formed. Since the solution of the hydrolyzed substance of alkoxide has superior stability and uniformity, the application of this solution is easily carried out, and a laminated body excellent in the adhesive strength of a formed thin oxide film can be obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for forming a metal or nonmetal oxide thin film on an organic polymer substrate, and a method for forming an oxide thin film on an organic polymer substrate and an oxide thin film obtained by the method. The present invention relates to a laminate consisting of.

A laminate consisting of an organic polymer base and a metal or non-metal oxide thin film can be used for mechanical protection, chemical protection, formation of a ferroelectric layer, ion conduction layer, electron conduction layer on the polymer surface, etc. It is carried out for the purpose of

(Prior art) One of the methods for forming such an oxide thin film is to form a thin film of metal or nonmetal alkoxide on a substrate and convert it into an oxide. It is preferable because it has relatively excellent adhesion and a wide selection of metal or nonmetal elements.

For example, Japanese Patent Application Laid-Open No. 61-276865 describes that a solution of silicon and titanium alkoxides is applied to a polymer surface and then partially hydrolyzed to form an inorganic polymer layer on the surface. , Japanese Patent Publication No. 62-9417 describes a method for producing a selectively transparent laminate, and describes a method for forming a titanium oxide thin film layer therein, which includes a step of coating an organic solvent of alkyl titanate. . The organic solvent used in the method described in Japanese Patent Publication No. 62-9417 may be various hydrocarbons, ethanol, isopropanol, butanol, etc. as long as it satisfies solubility, evaporability, and inertness for the solute. JP-A-61-276865 discloses isopropanol as a preferred solvent.

(Problem to be solved by the invention) However, considering the formation of a uniform thin film and the adhesion to the substrate, it is not sufficient to use any solvent; for example, hydrocarbons have poor compatibility with water; , is unsuitable as a solvent for forming metal oxide thin films, and cannot be used alone as a solvent, but only as an auxiliary solvent added to a hydrophilic solvent such as alcohol. Furthermore, even a mixed solvent of hydrocarbon and alcohol does not have sufficient film-forming properties, and is not preferred as a solvent for forming a metal oxide thin film on the surface of an optical material or the like. Among various solvents, alcohol is relatively preferable, but lower alcohols such as ethanol have too high polarity, resulting in insufficient adhesion between the formed metal oxide thin film and the substrate. There's a problem. On the other hand, alcohols having carbon atoms of 5 or more (C5) have problems in that the polarity of the solvent is too low, making it difficult to form a uniform coating solution, making it difficult to form a uniform thin film, and having poor stability of the solution.

As pointed out in JP-A No. 61-276865, isopropanol and butanol are relatively good among alcohols, and the adhesion of the formed metal oxide thin film to the organic substrate is also poor when other solvents are used. However, in consideration of the water resistance and solvent resistance of the formed thin film, there is an increasing demand for a film with even higher adhesion.

In view of this situation, the inventors of the present invention have conducted intensive studies and found that a metal oxide thin film with excellent film formability and adhesion can be formed by using an alcohol mixed solvent with a specific composition as a solvent. , arrived at the present invention.

(Means for Solving the Problems) That is, the gist of the present invention is to apply an alcohol solution of a metal or nonmetal alkoxide onto an organic polymer substrate, and then evaporate the solvent to form a thin oxide film on the substrate. A mixed solvent of an alcohol having 4 or less carbon atoms and an alcohol having 5 or more carbon atoms as a solvent for the metal or nonmetal alkoxide, and the volume of the alcohol having 5 or more carbon atoms in the mixed solvent. A method for forming an oxide thin film characterized by using an oxide thin film having a ratio of 5% to 70%, further comprising an organic polymer substrate obtained by the method and an oxide thin film formed thereon. It is in a laminate.

The type of metal in the metal alkoxide used in the present invention is not particularly limited and can be appropriately selected depending on the purpose. Excluding < II
Any of the IA N V A elements, manganese, iron, cobalt, nickel, and copper can be used, and these elements can also be used in an appropriate combination. Furthermore, excluding these and hydrogen, francium, and radium <IA, II
Element A, a lanthanide group element; L can also be used in combination with one or more elements selected from sulfur, selenium, tellurium, thorium, protactinium, uranium, and plutonium (hereinafter these elements are collectively referred to as metals). ).

The alkyl chain length of the alcohol component of the metal alkoxide preferably has 1 to 5 carbon atoms. Those having 6 or more carbon atoms are not preferred because organic substances tend to remain. The alkoxide components of the metal alkoxides may be the same or may be a combination of alkoxides with different chain lengths.

The solvent for the metal alkoxide used in the present invention needs to be a mixture of an alcohol having 4 or less carbon atoms and an alcohol having 5 or more carbon atoms. As the alcohol having 4 or less carbon atoms, methanol, ethanol, propatool, butanol, and any of these isomers can be used, but among these, ethyl alcohol and isopropyl alcohol are preferred in terms of polarity, boiling point, etc. Alcohols having 5 or more carbon atoms include amyl alcohol, hexyl alcohol,
Mention may be made of heptyl alcohol, octyl alcohol and their isomers. Alcohols with a carbon number of 9 or more have a high boiling point and require a lot of energy for evaporation in the solvent evaporation process after coating a metal alkoxide solution on a polymer substrate. -8 alcohols are preferred. Further, in the mixed solvent used in the present invention, the volume fraction of alcohol having 5 or more carbon atoms in the mixed solvent must be 5% or more and 70% or less. If this volume fraction is less than 5%, the polarity of the mixed solvent will be too large, resulting in insufficient adhesion between the produced metal particulate film and the substrate, and conversely, the volume fraction will be 70%. Exceeding this is not preferable because the polarity of the mixed solvent becomes too low and the coating solution containing the metal alkoxide, some water, and an acid as a hydrolysis catalyst becomes difficult to be uniform or lacks stability.

As the alcohol solution of metal alkoxide, one in which the concentration of metal alkoxide is 5 to 40% by weight is preferably used; if it is less than this lower limit, the film thickness obtained by one application will be too thin, and it is necessary to adjust the film thickness to a specified value. Therefore, it is necessary to repeat coating and drying many times, which is complicated, and if the concentration exceeds the upper limit, the coating liquid tends to gel, which is undesirable because it lacks stability.

The alcoholic solution of the metal alkoxide used in the present invention contains 3 to 10% by weight of water and 0.3 to 1% by weight for hydrolysis.
of acid is added. As this acid, an inorganic acid such as hydrochloric acid or an organic acid such as acetic acid can be used.

As this alcohol solution, a mixed solvent containing a metal alkoxide, water, and an acid may be applied as is to the surface of the polymer substrate, or this solution may be thoroughly stirred and subjected to some degree of hydrolysis and partial condensation before being applied. Good too. When hydrolysis and partial condensation are carried out, it is necessary to keep the reaction to such an extent that the solution after the reaction is maintained at a uniform and coatable viscosity, and the viscosity is preferably kept at 10 centipoise or less.

Various substances can be added to this alcohol solution as required, as long as they do not substantially inhibit hydrolysis and condensation. Examples of such additives include colloidal silica, silane coupling agents, dyes, pigments, and epoxy compounds.

As the substrate used in the present invention, any organic polymer can be used, and the type of polymer can be selected as appropriate depending on the purpose. When used for optical purposes, polymethyl methacrylate, polycarbonate, etc. , polystyrene, etc., and polyethylene terephthalate, polypropylene, etc. can also be used as the substrate, and the shape is not particularly limited, and may be a sheet, a film,
Various shapes such as various molded products can be used.

The solution used in the present invention may be formed by adding and mixing metal alkoxide, water, and acid to an alcohol mixed solvent;
From the viewpoint of reaction control, it is preferable to dissolve the metal alkoxide, water and acid separately in an alcohol mixed solvent and then mix the two.

In the present invention, the above solution is coated on an organic polymer substrate as it is or after (partial) hydrolysis or partial condensation, the solvent is evaporated, and the metal oxide condensate is heated to form a polymer. formed on a substrate. This coating and drying may be repeated multiple times as necessary, and when repeated, the same type of solution may be applied, or a different metal alkoxide solution may be applied each time. When solutions of different metals are applied, a laminate of different metals is obtained for each layer.

In the laminate of the present invention, the thickness of the metal oxide can be set to various values depending on the purpose, and the preferred thickness is 0.
Examples include those having a diameter of 0.03 to 0.3 μm.

(Example) The present invention will be further explained below using Examples.

In the examples, the thickness of the metal oxide thin film was measured using an ellipsometer (manufactured by Mizojiri Optical Kogyo Co., Ltd.), and the adhesion was measured by cross-cutting the surface of the laminate with a razor to form 100 squares of 1 mm x 11I11. After cutting and adhering Chiban 405) to the adhesive tape, the process of peeling off the adhesive tape was repeated three times, and the number of unpeeled areas in the thin film on the surface was used as a measure of adhesion. did.

Example 1 n-amyl alcohol 172.5ml, ethanol 1
5. Mix OmJZ to prepare a tetraalcohol mixed solvent,
Dissolve 31.2 g of ethyl silicate in this 100 ml, add 13.5 g of water and 1 ml of hydrochloric acid to the remaining alcohol mixed solvent.
, 5 g were mixed, and both were stirred and mixed at room temperature for 3 hours to effect hydrolysis and partial condensation, thereby obtaining a coating solution with a viscosity of 3.6 centiboaz. This was applied onto a polymethyl methacrylate plate by the dip method, and heated and dried at room temperature for 5 minutes and then at 80° C. for 30 minutes to evaporate the solvent and complete hydrolysis and condensation.

The thickness of the silicic acid condensed thin film of the obtained laminate was approximately 800 mm, and the adhesion was 100%.

Example 2 31.2 g of ethyl silicate was mixed with 4 g of n-amyl alcohol.
．． 5171LL, a solution dissolved in a mixed solution of ethanol 81ml, water 13.5g, hydrochloric acid 1.5g, n-
Amyl alcohol 4.5mfl, ethanol 81ml 1L
A laminate was obtained in the same manner as in Example 1, except that a solution consisting of (coating liquid viscosity: about 1.7 cp) was used. The thickness of the silicic acid condensed thin film of the obtained laminate was approximately 800 mm, and the adhesion was 100%.

Example 3 The same procedure as Example 2 was carried out except that a polyethylene terephthalate sheet was used instead of the polymethyl methacrylate plate. The adhesion of the silicic acid condensed thin film of the obtained laminate was 100%.

Comparative Example 1 A polymethyl methacrylate plate on which a thin film of about 1000 mm thick was formed on the surface was obtained in the same manner as in Example 2, except that isopropanol was used instead of n-amyl alcohol and ethanol. Liquid viscosity: approx. 2.5 cp). The adhesion of this thin film was 45%.

Comparative Example 2 A polyethylene terephthalate sheet on which a thin film of 1800 mm thick was formed on the surface was obtained in the same manner as in Example 3, except that isopropanol was used instead of n-amyl alcohol and ethanol. Approximately 3.0 cp).

The adhesion of this thin film was 40%.

Example 4.5 A polymethyl methacrylate plate with a thin film formed on the surface was obtained in the same manner as in Example 2 except that propyl silicate and butyl silicate were used instead of ethyl silicate. (Coating liquid viscosity: about 1.8 cp and about 1.9 cp, respectively) The adhesion of these thin films was 100%.

Example 6.7 A polymethyl methacrylate plate with a thin film formed on the surface was obtained in the same manner as in Example 2, except that propatool and butanol were used instead of ethanol. (Coating liquid viscosity: about 2.6 cp and about 3.1 cp, respectively) The adhesion of these thin films was 100%.

Example 8 A polymethyl methacrylate plate with a thin film formed on the surface was obtained in the same manner as in Example 2 except that n-hexanol was used instead of amyl alcohol (coating liquid viscosity was approximately 1.8 c).
p). The adhesion of these thin films was 100%.

Example 9.10 A polymethyl methacrylate plate with a thin film formed on the surface was obtained in the same manner as in Example 2, except that the amount of water was 6.7 g and 27.0 g, respectively (coating liquid viscosity was about 1.0 g, respectively). 5 cp, approximately 1.9 cp). The adhesion of these thin films is 100
%Met.

Example 11 240 g of titanium isopropoxide as a coating solution,
n-amyl alcohol 4.5 mjl, ethanol 81
Add 1.9 g of water, 0.4 g of hydrochloric acid, and 4.5 ml of n-amyl alcohol to the mixed solution of mu2. A mixed solution of 81 ml of ethanol was added, stirred, hydrolyzed, and partially condensed to a viscosity of approximately 1.6 centiboads. This was applied onto a polymethyl methacrylate plate using the dip method, and was heated at room temperature for 5 minutes. Then, the mixture was further heated and dried at 80° C. for 30 minutes to evaporate the solvent and complete the hydrolysis and condensation. The adhesion of the obtained laminate was 100%.

Example 12 24.0 g of zirconium isopropoxide as coating liquid
, n-amyl alcohol 4.5mJZ, ethanol 8
1 mL and acetylacetone 7 as a chelating agent.
．． To the mixed solution to which 5 ml was added, 7.5 g of water and 0.0 g of hydrochloric acid were added.
4g, n-amyl alcohol 4.5ml2. The coating solution obtained by adding a mixed solution of 81 mJZ of ethanol, stirring, hydrolysis, and partial condensation was applied onto a polymethyl methacrylate plate by the dip method, and then heated at room temperature for 5 minutes and then at 80°C for 3 minutes.
The mixture was dried by heating for 0 minutes to evaporate the solvent and complete hydrolysis and condensation. The adhesion of the obtained laminate was 100
%Met.

Example 13 31.4 g of aluminum butoxide, n-
4.5 ml of amyl alcohol1. Ethanol 81mfl
, 1.9 g of water to a mixed solution of 15.7 g of ethyl acetoacetate
A mixed solution of 0.4 g% 1-hydrochloric acid, 4.5 m of n-amyl alcohol, and 81 m of ethanol was added, stirred, hydrolyzed, and partially condensed, and the resulting coating solution was applied onto a polymethyl methacrylate plate by the dip method. The mixture was heated and dried at room temperature for 5 minutes and then at 80° C. for 30 minutes to evaporate the solvent and complete hydrolysis and condensation. The adhesion of the obtained laminate was 100%.

Example 14 Coating liquid: 31.4 g of ethyl silicate, 3.0 g of sodium methoxide, 4.5 mu of n-amyl alcohol
, a mixed solution of 81mu of ethanol, 13.5g of water, 1.5g of hydrochloric acid, 4.5rnQ of n-amyl alcohol, and 81mj of ethanol! Add a mixed solution of and stir to hydrolyze.
Using partially condensed material with a viscosity of 2.0 centipoise, this was applied onto a polymethyl methacrylate plate using the dip method, and the solvent was evaporated by heating and drying at room temperature for 5 minutes and then at 80°C for 30 minutes. At the same time, hydrolysis and condensation were completed. The adhesion of the obtained laminate was 100%.

(Effects of the Invention) According to the method of the present invention, various metal or non-metal oxide films can be formed on various base materials, and the solution of the alkoxide hydrolyzate has stability and uniformity. It is easy to apply because of its excellent properties, and has the effect that the formed oxide thin film has extremely excellent adhesion.

Claims (1)

[Claims] 1) A method in which an alcohol solution of a metal or nonmetal alkoxide is applied onto an organic polymer substrate, and then the solvent is evaporated to form a thin film of the metal or nonmetal oxide on the substrate. , a mixed solvent of an alcohol having 4 or less carbon atoms and an alcohol having 5 or more carbon atoms as a solvent for a metal or nonmetal alkoxide, and the volume fraction of the alcohol having 5 or more carbon atoms in the mixed solvent is 5% or more. A method for forming an oxide thin film, characterized in that an oxide thin film having a content of 70% or less is used. 2) A laminate comprising an organic polymer substrate and an oxide thin film formed thereon by the method of claim 1.