JPH03146530A - Coated synthetic resin molded product and its preparation - Google Patents

Abstract

PURPOSE:To prepare the subject molded product having excellent adhesivity to a silicon oxide coating film, excellent surface hardness and weather resistance and useful as a substrate for photomagnetic disks by forming a silicon oxide coating film on a primer layer and subsequently irradiating the coated surface with electron rays. CONSTITUTION:A primer layer comprising the thin film of at least one coupling agent selected from a silane coupling agent and a titanium coupling agent is formed on the surface of a synthetic resin molded product and a silicon oxide coating film is formed on the primer layer, followed by irradiating the coating layer with electron rays to provide the objective molded product. The synthetic resin molded product is preferably a polycarbonate resin molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a coated synthetic resin molded article having a silicon oxide coating formed thereon, and more specifically, the silicon oxide coating has excellent adhesion, wear resistance, and weather resistance. , relates to a coated synthetic resin molded article with improved surface conditions such as chemical resistance, and a method for producing the same.

[Prior Art] In order to modify the surface of a synthetic resin molded body, a technique of coating it with an oxide such as silicon dioxide, a metal nitride, or the like is known.

Conventionally, methods for coating oxide films, etc., include vacuum evaporation,
Various methods are known, such as sputtering, ion blasting, and plasma CVD, but these film forming methods require special equipment or are difficult to form on the surface of large molded bodies or molded bodies with complex shapes. It has some disadvantages, such as the fact that it is difficult to do so. Another problem is that the adhesion between the synthetic resin molded body and the coating is insufficient.

Recently, instead of directly coating the surface of a synthetic resin molded body with a silicon dioxide film, a silicon-containing film with good adhesion is coated on the surface of the synthetic resin molded body in advance as a primary film (primer), and then the silicon dioxide film is coated on top of that. A method for creating a silicon dioxide film that has good adhesion to the primary film has been proposed (Japanese Unexamined Patent Publication No. 12734/1983). That is, this method:
After coating and curing the synthetic resin molded article with at least one silicon compound selected from the group consisting of silicon compounds represented by the following formula, their hydrolysates, and colloidal silica to form a primary coating. A coated synthetic resin molded article, characterized in that the synthetic resin molded article with the primary coating is brought into contact with a supersaturated hydrofluorosilicic acid solution of silicon dioxide to form a silicon dioxide coating on the primary coating. This is a manufacturing method.

R'nS 1 (R2)4-n (wherein R1 is a hydrocarbon group having 1 to 6 carbon atoms, a vinyl group, a methacryloxy group, an epoxy group, an amino group, a mercapto group, an organic group having fluorine or chlorine, R2 is one or more bonding groups selected from an alkoxy group, an alkoxyalkoxy group, an acetoxy group, and a chlorine element, and n is O-4.) According to this method, compared to the conventional method, Since a coating with good durability can be obtained and a coating/dipping method can be used, it can also be applied to synthetic resin molded articles of large or complex shapes. However, in this method, although the adhesion between the silicon dioxide film and the primer is good, the adhesion between the synthetic resin molded article and the primer is still insufficient. The reason for this is presumed to be that almost no strong chemical bond is formed between the silicon compound used as a primer and the synthetic resin molded article. Therefore, in the method described above, the adhesion of the silicon dioxide coating to the synthetic resin molded article is still not sufficient.

In addition, the silicon dioxide film obtained by the above precipitation method contains about several percent of water, and unbonded 5i-O
Since several percent of H also remains, resistance to organic solvents such as acetone may be insufficient.

By the way, among synthetic resin moldings, polycarbonate resin moldings are transparent and have excellent impact resistance.

Although the body has good properties, the surface is easily scratched and worn.
It also has the disadvantage of being easily attacked by alkali, -'5°. Conventionally, various surface hardening coatings and coatings have been proposed, but because the surface does not have a strong polar group, the adhesion is insufficient, and the adhesion with silicon oxide is not strong. A coated polycarbonate resin molded article was not obtained.

Furthermore, many polymers such as polyethylene terephthalate, polyamide, polyetheretherketone, and polyimide have been developed and put into practical use as engineering plastics, but synthetic resin molded bodies made of these polymers are coated with a silicon oxide film. Therefore, no improved method for surface modification has been proposed.

[Problem to be solved by the invention]

An object of the present invention is to provide a coated synthetic resin molded article having a silicon oxide coating with excellent adhesion.

Another object of the present invention is to provide a silicon oxide-coated synthetic resin molded article with improved surface conditions such as abrasion resistance, weather resistance, and chemical resistance.

As a result of intensive research to overcome the problems of the above-mentioned conventional techniques, the present inventors have found that in normal primer treatment using a silane coupling agent, at best there is It was discovered that the adhesion between the polar groups was poor because only the electrostatic attraction between the polar groups was acting and no strong bond was formed.

Therefore, as a result of further research, we formed a thin film of a silane coupling agent or a titanium coupling agent on the surface of the synthetic resin molding, and then formed a silicon oxide coating.
By irradiating the top of these coating layers with electron beams, it is possible to form a primer layer in which chemical bonds are efficiently formed between the coating layer and the synthetic resin molded article, and the coupling agent can be treated with special treatment such as hydrolysis. It has been found that a primer layer with sufficient adhesion to the silicon oxide film can be formed even without this.

Moreover, it has been found that by electron beam irradiation, a silicon oxide film free of residual moisture and 5L-OH bonds can be obtained, and the solvent resistance is also improved.

The present invention has been completed based on these findings.

[Means to solve the problem]

That is, the gist of the present invention is as follows.

(1) (A) A primer layer consisting of a thin film of at least one coupling agent selected from silane coupling agents and titanium coupling agents, and (C) oxidation, on the surface of the (A) synthetic resin molded body. A coated synthetic resin molded article characterized in that a silicon coating is formed in this order and an electron beam is irradiated onto the silicon oxide coating.

(2) After forming a primer layer consisting of a thin film of at least one coupling agent selected from silane coupling agents and titanium coupling agents on the surface of the synthetic resin molding, a silicon oxide coating is formed on the primer layer. 1. A method for producing a coated synthetic resin molded article, which comprises forming a coated synthetic resin molded article, and then irradiating it with an electron beam.

Each component of the present invention will be explained below.

(Synthetic resin molded product) Examples of the synthetic resin molded product used in the present invention include polyvinyl chloride, polystyrene, polycarbonate, polymethyl methacrylate, polyamide, polyacetal,
Thermoplastic resins such as polyetherketone, polyimide, polyethylene terephthalate, polybutylene terephthalate, fully aromatic polyester, polyetherketone, polyetheretherketone, polyphenylene sulfide ketone, epoxy resin, polydiethylene glycol bisallyl carbonate, phenolic resin, polyurethane, etc. can be mentioned.

Among these, molded articles mainly composed of polymers having carbonyl bonds in repeating units can be particularly preferably used. A polymer having a carbonyl bond means a polymer having not only a ketone group but also a (>C=O) bond in the molecular structure such as an acid amide bond or an ester bond.

Among these, polycarbonate resins obtained by the phosgene method, in which a dihydroxydiaryl compound and phosgene are reacted, or the transesterification method, in which a dihydroxydiaryl compound and a carbonate ester such as diphenyl carbonate are reacted, are preferably used.

These polymers are used alone or in combination of two or more.

Further, the shape of the synthetic resin molded product is not particularly limited, and molded products of any shape can be used, from large products to those with complicated shapes.

(Coupling Agent) Examples of the silane coupling agent include general-purpose silane coupling agents containing a vinyl group, a methacryloxy group, an epoxy group, an amino group, or an isocyanate group.

Among these, organic silane compounds represented by the following formulas [I] and [rll] can be preferably used.

Xn5iY4-n [] [wherein, carbon number 1-10
is a hydrocarbon group, n is an integer of 1 to 3. ] Specifically, γ-aminopropyltriethoxysilane,
γ-Aminopropyltrimethoxysilane, γ-Incyanatobrobyltrimethoxysilane, γ-Isocyanatepropyltriethoxysilane, γ-Isocyanatepropylmethyldimethoxysilane, Glycidoxypropyltrimethoxysilane, Glycidoxypropyltriethoxy Silane, Glycidoxypropyltripropoxysilane, Glycidoxypropylmethyldimethoxysilane, Glycidoxypropylmethyljethoxysilane, Glycidoxypropylethyldimethoxysilane, Glycidoxypropylethyljethoxysilane, Glycid Xypropylbutyldimethoxysilane, glycidoxypropylbutyljethoxysilane, 2-(2,3-epoxycyclohexyl)ethyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2 −
aminoethyl)aminopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane, N-(triethoxysilylprobyl)urea, aminomethyltriethoxysilane, N-(β-amino ethyl)aminomethyltrimethoxysilane, aminomethyljethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinylacetoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. can be mentioned.

R, , Si (OOR'), [II] [wherein R is a hydrocarbon group having 1 to 6 carbon atoms, a vinyl group, a methacryloxy group, an epoxy group, an amino group, a mercapto group, an organic group having fluorine or chlorine R' is one or more bonding groups selected from an alkyl group, an acyl group, and an arylalkyl group, and n is an integer of 1 to 4.

] Specifically, for example, vinyltris(t-butylperoxy)silane, vinyltris(cumene oxy)
Silane, vinyltris(acetylperoxy)silane,
Vinyltris(benzoylperoxy)silane, vinyltris(lauroylperoxy)silane, γ-glycidoxypropyltris(t-butylperoxy)silane,
γ-glycidoxypropyltris(cumemberoxy)silane, γ-glycidoxypropyltris(acetylperoxy)silane, γ-glycidoxypropyltris(benzoylperoxy)silane, γ-glycidoxypropyltris(benzoylperoxy)silane Viltris(lauroylperoxy)silane, γ-methacryloxypropyltris(t-butylperoxy)
Silane, γ-methacryloxypropyltris(cumemberoxy)silane, γ-methacryloxypropyltris(acetylperoxy)silane, γ-methacryloxypropyltris(benzoylperoxy)silane, γ-
Examples include methacryloxypropyltris(lauroylperoxy)silane.

Examples of titanium-based coupling agents include isopropyltriisostearoyltitanate, isopropyltrioctanoyltitanate, isopropylisostearoyldiacryltitanate, isopropyltri(N-aminoethyl-aminoethyl)titanate, and tetraoctylbis(ditridecylphosphite). ) titanate, isopropyl tricumylphenyl titanate, triethanolamine titanate, titanium acetylacetonate,
Examples include titanium ethyl acetate and titanium lactate.

These coupling agents can be used alone or in combination.

(Method of forming a primer layer) To form a thin film of a coupling agent on the surface of a synthetic resin molded article, the coupling agent is dissolved in an alcohol such as methanol, ethanol, isopropanol, or isobutanol. The solution may be applied to a synthetic resin molded article by a spin cord method, dipping method, spraying method, etc., and then dried to remove the solvent. In the case of synthetic resin molded articles with large chambers or complex shapes, the dipping method is preferred.

The concentration of the coupling agent during the night can be determined as appropriate, but apply! The solution is usually 0.1 to 5% by weight, preferably from 5 taka to 500 taka. Further, drying after application is performed at room temperature or in a dryer. At room temperature, about 1 to 2 hours,
It is air-dried, and if it is heated, it is dried in a hot-air dryer or the like under elevated temperature conditions, for example, at about 90° C., for about 1 to 2 hours. These drying conditions can be appropriately selected by those skilled in the art.

After photo-silicon priming, a silicon oxide film is formed on the thin film of the coupling agent.

As the silicon oxide film, Si such as 5ift and St○ are used.
Conventionally known Si-based oxide films such as n, (2≧X≧1), SiA[ON, etc. can be applied. As a method for forming the film, usual methods such as vapor deposition, sputtering, plasma CVD, and liquid phase growth can be employed.

Among silicon oxide coatings, silicon dioxide coatings are preferred. Methods for forming a silicon dioxide film on the primer layer subjected to the primer treatment include a CVD method using silane gas, a sputtering method using a quartz plate as a target, a dipping method using an organic solvent of an organosilicon compound, or There is a precipitation method in which silicon dioxide is immersed in a supersaturated hydrofluorosilicic acid solution to deposit a silicon dioxide film. Among these, the precipitation method is preferred because it is easy to work with and can form a uniform film.

As for this precipitation method, a known method disclosed in detail in JP-A-61-12734 can be applied. What is supersaturated hydrofluorosilicic acid solution of silicon dioxide?
After dissolving silicon dioxide (silica gel, aerosil, silica glass, other silicon dioxide-containing materials, etc.) in a hydrofluorosilicic acid solution, water or a reagent (boric acid, aluminum chloride, etc.) is added to the supersaturated state of silicon dioxide. This is what I did. The primer-treated synthetic resin molded body may be brought into contact with this treatment liquid. The contact may be carried out by immersing the synthetic resin molded body in the treatment liquid or by allowing the treatment liquid to flow down onto the surface of the molded body, but the immersion method is preferable in order to form a uniform coating.

The concentration of hydrofluorosilicic acid in the treatment solution is preferably 1 to 2 mol/I, particularly after saturating silicon dioxide in an aqueous solution of hydrofluorosilicic acid that is more concentrated than 2 mol/I2, diluted with water to give a concentration of 1 to 2 mol/I. A concentration of mol/min is desirable because the film formation rate is fast and coating can be carried out efficiently. When adding boric acid to create a supersaturated state, the amount added is 1X10-" to 4% per mole of hydrofluorosilicic acid in the treatment solution.
0 x 10-" moles, preferably 1.2 x 10-" to 1 o
A range of x11" moles is desirable for forming a fast and homogeneous coating.

In order to efficiently obtain a homogeneous film, it is preferable to continuously add and mix the boric acid aqueous solution while the synthetic resin molded body is immersed in the treatment liquid, and to circulate the treatment liquid and filter it with a filter. When using silica gel as a source of silicon dioxide, a filter with a pore size of 1.5 μm or less is used, and when using other materials such as silica glass, a filter with a pore size of 10 μm is used.
The following filters are preferred.

In addition, when placing the treatment liquid in an immersion tank and bringing it into contact with a synthetic resin molded article, it is important to allow the treatment liquid to flow in a laminar flow on the surface of the molded article during immersion to ensure an even and homogeneous flow. Preferred for forming a film.

The thickness of a silicon oxide film such as silicon dioxide can be adjusted as appropriate depending on the purpose of use, but the purpose of surface modification can usually be achieved with a coating of several hundred to several thousand. .

In the present invention, a thin film made of a coupling agent and a silicon oxide film are sequentially formed on the surface of a synthetic resin molded body, and then an electron beam is irradiated. It is presumed that chemical bonds are formed between the synthetic resin molded body and the coupling agent thin film due to the electron beam irradiation.

The electron beam irradiation is usually performed at a dose rate of about 0.05 to 10 Mrad/S in an atmosphere of an inert gas such as argon gas. The dose varies depending on the type of material, but it should be in the range of 0.5 to several tens of Mrad, which does not decompose or deteriorate the synthetic resin surface layer, and for polycarbonate, A''f, 10 Mrad or less. is preferred.

In addition, by performing electron beam irradiation and a coating test in advance, those skilled in the art can appropriately select a preferable range of the dose depending on the type of resin.

By irradiating the electron beam, a chemical bond is generated between the coupling agent and the synthetic resin molded body, and a strong bond is generated between the thin film of the coupling agent and the surface of the synthetic resin molded body. Further, the adhesion between the coupling agent thin film and the silicon oxide film is good.

In the conventional primer treatment using a silicon compound such as a silane coupling agent, no strong chemical bond is formed between the primer (first coating layer) and the surface of the synthetic resin molded article.

Even if heat treatment is performed after treatment with a silane coupling agent, only a small portion of chemical bonds are formed with the synthetic resin molding, and adhesion is insufficient. However, there are problems in that the heat conduction efficiency is poor and stress is generated in the synthetic resin molded body due to heat.

Additionally, in primer treatment using a normal silane coupling agent, in order to improve adhesion to the silicon oxide film, it is necessary to hydrolyze alkoxy groups and convert them into hydroxyl groups before applying to the base material. . Furthermore, the binding properties between the primer molecules were also weak.

On the other hand, when a thin film of coupling agent (primer layer) and a silicon oxide film are formed on the surface of a synthetic resin molded body and then irradiated with an electron beam, a chemical reaction occurs between the synthetic resin molded body and the coupling agent of the primer. Bonding occurs and the two are firmly bonded. As the synthetic resin molded product, a molded product mainly composed of a polymer having a carbonyl bond (>C═O) is particularly effective.

Further, since the primer layer and the silicon oxide film are sequentially formed and then irradiated with electron beams, it is possible to simultaneously form a strong bond between the silicon oxide film and the primer layer. Furthermore, since moisture remaining in the formation of a silicon oxide film by the above-mentioned precipitation method can be removed by electron beam irradiation energy, the surface of the silicon oxide film can be made into a strong Si film and its solvent resistance can be improved. can.

According to the electron beam irradiation method, ■Energy is contained in each individual electron, so the amount of energy can be easily controlled by manipulating the accelerating voltage, and ■Since high energy is integrated, synthetic resin Since the reaction site between the molded body and the primer can be easily reached, a chemical bond is reliably formed between the two in a short time.

〔Example〕

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1] γ-Glydoxypropyltrimethoxysilane dissolved in inbutanol was applied to the entire surface of a flat plate (100 mm long, 100 mm wide, 2 mm thick) made of polycarbonate resin. Night (1
% by weight) was applied using a spin coater, and then heated and dried with hot air at 90° C. for 5 minutes. The film thickness was approximately 40 people.

A silicon dioxide film was deposited on the polycarbonate plate subjected to the above treatment using a silicon dioxide film manufacturing apparatus similar to that shown in JP-A-61-12734.

That is, the silicon dioxide coating manufacturing apparatus has a dipping tank consisting of an outer tank and an inner tank, and the space between the inner tank and the outer tank is filled with water. This water is heated with a heater to a temperature of 35° C., and is stirred with a stirrer to make the temperature distribution uniform. The inner tank consists of a front part, a middle part, and a rear part, and each part is filled with an aqueous solution of hydrofluorosilicic acid at a concentration of 2.0 mol/4, in which silicon dioxide is dissolved and saturated, using industrial silica gel powder as a source of silicon dioxide. It is filled with a reaction solution of 3I2 diluted to 20% using 3I2. At this point, the circulation pump was activated to discharge the reaction liquid from the rear part of the inner tank in constant amounts, filter it with a filter, and start circulating the treated liquid back to the front part of the inner tank.

Thereafter, aqueous solution of 0.5 mol/min of boric acid was continuously added to the rear of the inner tank and maintained for 10 hours. In this state, the reaction solution became a treatment solution having an appropriate degree of silicon dioxide supersaturation.

Here, the absolute removal rate of the filter was adjusted to 1.5 μm, and the circulating rate of the processing liquid was adjusted to 240 mj2/min (since the total amount of the processing liquid was about 3°C, the circulating rate was 8%/min).

Then, the polycarbonate treated above was immersed vertically in the middle of the flat inner tank, and under the conditions described above (0.5 mol/I2 boric acid aqueous solution was added at 0.2 mj2/min, and circulation was performed at 8%/min). , filtered through a 1.5 μm filter) for 16 hours.

The thickness of the silicon dioxide coating layer on the resulting coated polycarbonate plate was about 5,000.

Next, the entire surface of the coated polycarbonate plate was irradiated with an electron beam. The electron beam has a dose rate of 1.6 Mrad/S and a dose of 8
．． Irradiation was performed using an OMrad in an argon gas atmosphere.

[Example 2] Polycarbonate resin flat plate (length 100 mm, width 100 m
An isopropyl alcohol solution (1% by weight) of isopropyl isostearoyldiacryl titanate was applied to the entire surface of the substrate (2 mm thick) using a spin coater, and then heated and dried with hot air at 70° C. for 5 minutes. The film thickness was approximately 30 people.

A silicon dioxide film was formed on the entire surface of the primer-treated polycarbonate resin flat plate in the same manner as in Example 1.

The film thickness was approximately 5,500 people.

Then, the entire surface of the coated flat plate was irradiated with an electron beam in the same manner as in Example 1.

[Example 3] A silicon dioxide-coated polycarbonate resin flat plate was prepared in the same manner as in Example 1 except that γ-aminopropyltriethoxysilane was used as the silane coupling agent.

[Example 4] A silicon dioxide-coated polycarbonate resin flat plate was prepared in the same manner as in Example 2 except that titanium ethyl acetoacetate was used as the titanium-based coupling agent.

[Comparative Example 1] A polycarbonate resin plate coated with silicon dioxide was obtained in the same manner as in Example 1 except that electron beam irradiation was not performed.

Bakukai Tachizuki 1 <Cold/Hot Cycle Test> The silicon dioxide-coated polycarbonate resin flat plates obtained in Examples 1 to 4 and Comparative Example 1 were subjected to a cold/hot cycle test to determine the occurrence of peeling between the polycarbonate resin flat plate and the silicon dioxide coating. The situation was visually observed.

In the cold cycle test, the temperature was left at 80°C and 90% RH for 2 hours, then the concentration was lowered over 1 hour, and the temperature was lowered to -25°C.
The operation of leaving the sample at 40% RH for 2 hours was repeated.

The results are summarized in Table 1.

(Margin below) Table 1: Solvent Resistance Test> A silicon dioxide-coated polycarbonate resin flat plate was immersed in acetone for 10 minutes, air-dried at room temperature, and then observed and evaluated on the following three scales.

○: No change at all, Δ: Local whitening, ×: Whole whitening or deformation. In Examples 1 to 4, the sample was 0.0.5.4.0 A silicon dioxide-coated polycarbonate resin flat plate prepared by changing the temperature to .80 M r a d was used.

The results are shown in Table 2.

Table 2 [Examples 5 to 8] Electron beam irradiation treatment was performed in the same manner as in Example 1, except that a hexane solution (1% by weight) of the following various silyl peroxide compounds was applied as a silane coupling agent. A polycarbonate resin plate coated with silicon dioxide was obtained.

Example 5: Vinyltris(t-butylperoxy)silaneExample 6: Vinyltris(cumemberoxy)silaneExample 7: Vinyltris(benzoylperoxy)silaneExample 8: γ-methacryloxypropyltris(t-butylperoxy)silane Table 3 shows the results of a thermal cycle test performed on the obtained sample of oxy)silane.

Table 3 Table 4 also shows the results of solvent resistance tests conducted in Examples 5 to 8 by varying the amount of electron beam irradiation.

Table 4 (blank below) [Effects of the invention J According to the present invention, a primer layer that is firmly bonded to both the synthetic resin of the base material and the silicon oxide coating can be formed simply by irradiating with an electron beam. . According to the present invention, adhesion with the silicon oxide film, surface hardness, weather resistance,
A molded article with significantly improved chemical resistance, moisture permeability, hygroscopicity, etc. can be obtained. In particular, by taking advantage of the transparency, lightness, ease of processing, and impact resistance of polycarbonate resin, it is possible to obtain a silicon oxide-coated polycarbonate resin molded product with improved physical properties, which were previously found to be insufficient. It can now be used in a wide range of fields, including fields that could not be used due to the

The coated synthetic resin molded article of the present invention can be used in a wide range of fields, including, for example, substrates for magneto-optical disks, substrates for magnetic disks, and synthetic resin substrates as substitutes for window glass in cars and trains.

Claims (5)

[Claims] (1) A primer layer consisting of a thin film of at least one coupling agent selected from (B) a silane coupling agent and a titanium coupling agent, and (C) an oxidation A coated synthetic resin molded article characterized in that a silicon coating is formed in this order and an electron beam is irradiated onto the silicon oxide coating. (2) The coated synthetic resin molded article according to claim 1, wherein the synthetic resin molded article is a polycarbonate resin molded article. (3) After forming a primer layer consisting of a thin film of at least one coupling agent selected from silane coupling agents and titanium coupling agents on the surface of the synthetic resin molding, a silicon oxide coating is formed on the primer layer. 1. A method for producing a coated synthetic resin molded article, which comprises forming a coated synthetic resin molded article, and then irradiating it with an electron beam. (4) The method for producing a coated synthetic resin molded article according to claim 3, wherein the synthetic resin molded article is a polycarbonate resin molded article. (5) The silicon oxide coating is a silicon dioxide coating, and the synthetic resin molded article on which the primer layer is formed is brought into contact with a supersaturated hydrofluorosilicic acid solution of silicon dioxide, so that the silicon oxide coating is coated on the primer layer. The method for producing a coated synthetic resin molded article according to claim 3 or 4, wherein a silicon dioxide film is deposited.