JPH0762087B2 - Method for producing molded body of silicon dioxide-coated polycarbonate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a silicon dioxide-coated polycarbonate molded body, and particularly to a surface of a polycarbonate molded body such as a polycarbonate disc for an optical disc substrate having fine irregularities on the surface. The present invention relates to a method for producing a silicon dioxide coating capable of maintaining the surface irregularities and forming a silicon dioxide coating having excellent durability and a uniform thickness.

[Prior Art] Transparency is required for a substrate of a memory material using light. As the transparent disc material, glass or transparent plastic is likely to be used. Glass and plastic as disc materials have their own advantages and disadvantages, and it is difficult to select the material, but molding processability, safety,
In terms of manufacturing cost, plastic is considered superior.

However, because plastics such as PMMA and PC have good air permeability and water permeability, they may cause warpage, and when used as a disk substrate, O ₂ and H ₂ O that penetrate from the back surface of the substrate may cause recording film layer In the recording layer, resulting in deterioration of performance due to oxidation of the recording layer. Therefore, in order to prevent this, a process of providing a base film of Si ₃ N ₄ , SiO, SiO ₂ or the like is generally performed between the substrate and the recording layer. These base films are usually formed by a vacuum method such as vapor deposition or sputtering.

On the other hand, as a method for producing a silicon dioxide film, in addition to such means such as vapor deposition and sputtering, a silicon dioxide film is formed on the surface of a substrate by immersing the substrate in a hydrosilicofluoric acid solution in a supersaturated state of silicon dioxide. There is known a method (hereinafter, abbreviated as "precipitation method") for forming a film (for example, JP-A-62-20876).

Particularly, regarding a method of forming a silicon dioxide film on a plastic molded body by a deposition method, an organic silicon compound, a hydrolyzate thereof and a silicon compound such as colloidal silica are coated and cured on the plastic molded body to form a primary coating. After that, a method of forming a silicon dioxide film on the primary film by a precipitation method is known (for example, JP-A-61-2734).

[Problems to be Solved by the Invention] When a silicon dioxide film is formed on the surface of a plastic molded body by a conventional vacuum method such as vapor deposition or sputtering, a high-quality film is formed because gas is generated from the substrate during the film formation. Hard to get.

It is difficult to form a film formed on the surface of the optical disk substrate, the grating lens, etc., which follows the groove-shaped irregularities for tracking.

The obtained film has poor adhesion to the resin substrate and is easily peeled off under a load of temperature and humidity.

In contrast to this, the deposition method enables low-temperature film formation as compared with the silicon dioxide film formation method by the vacuum method.

 A uniform film can be formed on the irregular surface.

When the underlying film of the optical disk substrate is limited to the silicon dioxide film, it can be expected that the above-mentioned problems of the sputtering or vapor deposition method can be solved to some extent.

However, in order to obtain a silicon dioxide film that is uniformly transparent and has strong adhesion to a plastic molding by the precipitation method,
It is necessary to thicken the primary coating obtained by coating and curing the organosilicon compound, a hydrolyzate thereof and a silicon compound such as colloidal silica to 0.5 to 30 μm. Therefore, when applied to a plastic substrate having a fine uneven surface such as an optical disk substrate or a grating lens, the uneven shape of the surface disappears by forming such a primary film, so that the primary film However, there is a problem in that even if silicon dioxide is coated thereon by a deposition method, an optical disk substrate, a grating lens, etc. suitable for practical use cannot be produced.

[Means and Actions for Solving Problems] The present invention solves the above-mentioned conventional problems, and particularly a polycarbonate molded article as a plastic molded article can maintain surface irregularities and has a uniform thickness excellent in durability. The present invention provides a method for producing a silicon dioxide coating of sea urchin.

According to the present invention, a polycarbonate molded body is coated and cured with an organic silicon compound to form a primary coating, and then the polycarbonate molded body is brought into contact with a supersaturated hydrofluoric acid solution of silicon dioxide for the primary coating. In the method for producing a silicon dioxide-coated polycarbonate molded article, which comprises forming a silicon dioxide coating on the primary coating, the primary coating comprises a silicon compound having an amino group and a silicon compound represented by the following general formula (I). A coating solution containing at least one of the hydrolyzates, wherein the content of the silicon compound having an amino group is 0.2% by weight or more and the total concentration of the silicon compounds is 5% by weight or less. And a method for producing a silicon dioxide-coated polycarbonate molded article, which is characterized in that it is formed by drying.

▲ R ¹ _n ▼ Si (R ² ) _4-n (I) (In the formula, R ¹ is a hydrocarbon group having 2 or less carbon atoms such as ethyl group and vinyl group, or mercapto group, and 3 carbon atoms having a hydroxyl group. The following organic groups, R ² is one or more bonding groups selected from an alkoxy group, an alkoxyalkoxy group, an acetoxy group, and a chlorine element, and n is 0 or 1.) Direct plastic molding by a precipitation method When a silicon dioxide film is coated on the body surface, the adhesiveness is weak due to the poor reactivity and wettability of the hydrosilicofluoric acid solution with the plastic, and only an uneven film can be obtained. If the surface is coated with an organosilicon compound in advance and cured, the silanol groups on the surface will bond with the silicon component in the hydrofluoric acid solution, so the adhesion and unevenness of the silicon dioxide film obtained by the precipitation method To improve Possible it is.

However, the first obtained by coating and curing the organosilicon compound
When making the film thickness of the next film as thin as several hundred angstroms or less, it is a uniform film without any unevenness by the precipitation method.
In order to obtain a silicon dioxide film having a strong adhesive force, it is necessary to select an organosilicon compound depending on the type of plastic.

The inventors of the present invention have conducted extensive studies on an organosilicon compound suitable for forming a primary coating, which is suitable for a polycarbonate molded article, and as a result, a silicon compound having an amino group,
The present invention has been completed by finding that a mixed system having a specific ratio of at least one selected from the group consisting of the silicon compound represented by the general formula (I) and a hydrolyzate thereof is optimal.

The present invention will be described in detail below.

In the present invention, among the silicon compounds used for forming the primary film, the silicon compound having an amino group is γ
-Aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane,
N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane and the like are mentioned. These silicon compounds are effective for obtaining a silicon dioxide film having strong adhesion by the precipitation method.

As the silicon compound represented by the general formula (I), methyltriethoxysilane, tetraethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane. , Γ-hydroxypropyltrimethoxysilane and the like. As the hydrolyzate of the silicon compound represented by the general formula (I), an alkoxy group, an alkoxyalkoxy group, an acyloxy group, or a chlorine element in which a part or all of the chlorine element is substituted with a hydroxyl group in the silicon compound, In addition, some of the substituted fishery groups are naturally condensed. These hydrolyzates can be easily obtained by hydrolysis in the presence of an acid in a mixed solvent such as water and alcohol.

These silicon compounds are effective for improving the film forming property of the silicon dioxide film by the precipitation method and for obtaining a uniform and uniform silicon dioxide film.

That is, when the primary coating film is formed only by the silicon compound having an amino group, unevenness or white turbidity may occur in the silicon dioxide coating film obtained by the precipitation method in some cases. Such a defect can be prevented by mixing and using a silicon compound having an amino group and a silicon compound represented by the general formula (I) (or a hydrolyzate thereof).

However, even if the primary film is formed by the precipitation method using only the silicon compound represented by the general formula (I) (or a hydrolyzate thereof), it gives only a uniform but poorly adherent silicon dioxide film. However, it must be mixed with a silicon compound having an amino group.

As the silicon compound (or its hydrolyzate) represented by the general formula (I), one type may be used alone, or two or more types may be used in combination. Similarly, the silicon compound having an amino group may be used alone or in combination of two or more.

In the present invention, a coating liquid containing the above-mentioned silicon compound having an amino group and one or more selected from the group consisting of the silicon compound represented by the general formula (I) and a hydrolyzate thereof is applied to a polycarbonate molded body. By coating and drying, a coating film as shown in FIG. 1 is formed. This coating solution contains 0.2% by weight or more of a silicon compound having an amino group in the solution.
It is prepared by dissolving it in various solvents so that the total silicon compound concentration is 5% by weight or less.

The solvent used here must be selected in consideration of the solubility of the substrate and the wettability with the substrate. Therefore, solvents such as toluene and xylene that dissolve the polycarbonate should not be used. Also, the single use of water, which has poor wettability with the substrate, should be avoided. However, adding a surfactant,
This does not apply to the case where the wettability with the substrate is improved.

As a coating method, a dip coating method is suitable, and as a drying and curing method, any method such as a method using heat, ultraviolet rays, or an electron beam can be adopted.

The formed primary coating is formed on a glass substrate (for example, ordinary plate glass, soda lime glass, etc.) by setting the coating conditions such as the concentration of the silicon compound in the coating liquid and the pulling rate during dip coating. , When the film is formed under the same conditions, the film thickness is 5 to 100 nm, preferably 1
It is desirable that the film is formed under the condition that a film having a thickness of 0 to 50 nm is formed.

Here, the primary coating film formed on the polycarbonate substrate is thinner than the primary coating film formed on the glass substrate because the corresponding silicon compound permeates inside.
Therefore, if the primary coating is a coating formed under the condition that a coating having a thickness of up to about 100 nm is formed on the glass substrate, a coating that maintains the surface irregularity of the optical disk substrate can be obtained. If the primary coating is formed under the condition that the thickness is greater than 100 nm when formed on a glass substrate, the shape following property may be deteriorated. In addition, the condition that the film thickness is thinner than 5 nm on the glass substrate is not suitable because it causes a decrease in the adhesion strength of the silicon dioxide film obtained by the precipitation method.

In the present invention, in order to form the primary coating film having such a film thickness, the concentration of the silicon compound in the coating solution is preferably 0.2 to 5% by weight, particularly 0.5 to 2% by weight. However, in order to prevent the adhesion of the silicon dioxide film obtained by the precipitation method from decreasing, the concentration of the silicon compound having an amino group in the coating solution is 0.2% by weight or more, particularly 0.5% by weight.
The above is preferable.

As described above, the condition for forming the film thickness of the primary film is expressed by using the glass substrate as a monitor, when the film thickness of the primary film on the polycarbonate substrate is directly measured, the polycarbonate substrate has a smooth surface. It is difficult to measure the film thickness with a contact needle type film thickness measuring device.

Since the silicon compound applied to the polycarbonate substrate gradually diffuses inside the polycarbonate substrate, the interface between the polycarbonate substrate and the silicon compound is unclear,
The film thickness cannot be measured even by observation with an electron microscope or the like.

There are two problems.

In this way, the primary coating formed on the polycarbonate substrate has the silicon compound having an amino group and the silicon compound represented by the general formula (I) or its hydrolyzate permeate into the polycarbonate substrate. If the film thickness is below a certain level, the shape of the optical disk substrate can be maintained.
In addition, a silicon compound having an amino group provides high adhesion of a silicon dioxide film.

In the present invention, the polycarbonate substrate on which the primary coating is formed is then contacted with a solution of silicon dioxide in a supersaturated hydrofluoric acid solution to form a silicon dioxide coating on the primary coating.

As a hydrosilicofluoric acid solution in a saturated state of silicon dioxide (hereinafter, abbreviated as “treatment liquid”), a hydrosilicofluoric acid solution and silicon dioxide (silica gel, aerogel, silica glass, other silicon dioxide-containing substances, etc.) can be used. ) Is dissolved, and then water or a reagent (boric acid, aluminum chloride, metallic aluminum, etc.) is added, or the temperature of the treatment solution is raised to obtain a supersaturated state of silicon dioxide.

In the present invention, the concentration of hydrogen silicofluoride in the treatment liquid to be brought into contact with the substrate of the polycarbonate molded article with the primary coating is preferably 1 to 3 mol / particularly, 3 mol / concentrated aqueous hydrosilicofluoric acid solution. After saturating silicon dioxide to
It is desirable to dilute with water to a concentration of 1 to 3 mol / mol because the film formation rate is high and the film formation can be performed efficiently.

Further, the treatment liquid is (a) continuously added and mixed with an aqueous solution of an additive such as boric acid or aluminum chloride even when contacting with the molded body, or a metal such as aluminum is dissolved and mixed, It is a processing solution in which the degree of supersaturation is always maintained by means such as temporarily cooling the temperature to saturate the silicon dioxide and then raising the temperature again. (B) Treatment of 3% or more of the total amount of the processing solution per minute It is preferable that the liquid is a treatment liquid that is filtered back with a filter.

Here, at the time of contact, it is preferable to continuously add and mix an aqueous solution of boric acid or the like or dissolve and mix a metal such as aluminum in order to improve the rate of formation of the film.
In the case of boric acid, the addition amount is 1% hydrosilicofluoric acid in the treatment liquid.
The range of 5 × 10 ⁻⁴ mol / Hr to 1.0 × 10 ⁻³ mol / Hr is preferable with respect to the mol, and when dissolving aluminum metal, the dissolution amount is 1 mol of hydrosilicofluoric acid in the treatment liquid. On the other hand, the range of 1 × 10 ⁻³ mol / hr to 4 × 10 ⁻³ mol / hr is preferable.

In addition, circulating 3% or more of the treatment liquid is effective for continuously obtaining a homogeneous coating, and filtering the treatment liquid with a filter is preferable for obtaining a coating having no uneven shape.

When the treatment liquid is placed in a dipping bath and brought into contact with the molded body, it is necessary to allow the treatment liquid to flow as a laminar flow on the surface of the molded body during immersion in order to obtain a uniform and uniform film. It is effective.

The silicon dioxide film obtained by such a deposition method contains adsorbed water and silanol groups, and in order to remove these, it is preferable to subject the film to heat treatment by high frequency waves or the like.

It should be noted that the silicon compound having an amino group is effective as a silicon compound for forming a silicon dioxide film on the surface of a plastic molding as shown in FIG.
As disclosed in the following reference example, it was found that this silicon compound having an amino group is extremely effective for forming a thin film of a primary coating on a polycarbonate molded body. .

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Example 1 A mixture of 0.5 g of N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and 1.2 g of vinyltris (β-methoxyethoxy) silane was added to ethanol: isopropyl alcohol: n-butyl alcohol = 5: 3: 2. A polycarbonate plate having a length of 100 mm and a width of 1 mm was immersed in a solution (silicon compound concentration: about 0.9% by weight) dissolved in a mixed solvent (volume ratio) of 250 ml, and pulled up at a speed of 15 cm / min, then at 100 ° C. Was dried for 1 hour in the hot air drying oven. When the primary coating film was formed on the glass substrate under the same conditions as the above operation, the film thickness was about 10 nm.

On the obtained polycarbonate flat plate with the primary coating,
A silicon dioxide film was formed using the silicon dioxide film manufacturing apparatus shown in the figure.

In FIG. 1, the immersion tank comprises an outer tank 1 and an inner tank 2, and water 3 is filled between the inner tank 2 and the outer tank 1. This water is heated by the heater 4 so as to have a temperature of 40 ° C., and is stirred to make the temperature distribution uniform. The inner tank 2 is composed of a front part 6, a middle part 7 and a rear part 8. Each part uses an industrial silica gel powder as a supply source of silicon dioxide to dissolve and saturate silicon dioxide, and a 2.5 mol / hydrofluoric acid solution. 6.5 is met.

With such a device, first, the circulation pump 10 is operated to pump out the reaction liquid in the rear part 8 of the inner tank in a fixed amount,
The treatment liquid circulation was started by filtering at 11 and returning to the inner tank front part 6.

After that, it was dipped in the rear part 8 of the inner tank of 123 Al plates having a length of 50 mm, a width of 50 mm and a thickness of 3 mm, and kept for 10 hours. In this state, the reaction liquid became a treatment liquid having an appropriate degree of SiO ₂ supersaturation. Here, the absolute removal rate of the filter 11 is 1.5 μm, and the processing solution circulation flow rate is 520.
The flow rate was adjusted to 8 ml / min (since the total amount of the treatment liquid was about 6.5, the circulation flow rate was 8% / min). Then, the polycarbonate flat plate 9 on which the primary coating is formed by the silicon compound is vertically dipped in the middle part 7 of the inner tank under the above-mentioned conditions (that is, the Al plate 3).
The plate was kept immersed for 8% / min circulation and filtered through a 1.5 μm filter) for 120 minutes.

The film thickness of the silicon dioxide film obtained by the above treatment was about 90 nm. This film forming part is processed by ESCA (Electron Spectroscopy
As a result of analysis using for Chemical Analysis, it was confirmed that most of them consisted of SiO ₂ .

The obtained silicon dioxide coating had a strong adhesive force that did not peel at all in a test in which a cellophane adhesive tape was attached and peeled off. Further, when the above-mentioned silicon dioxide coated polycarbonate substrate was immersed in boiling water for 1 hour, no change was observed in the coating and it was found that the coating had good adhesion.

Example 2 Silicon dioxide was prepared in the same manner as in Example 1 except that a polycarbonate optical disk substrate (having a groove having a depth of 0.07 μm, a width of 0.8 μm and a pitch of 1.6 μm) was used in place of the polycarbonate flat plate having a flat surface. A coating (about 80 nm) was created.

As a result of observation with an electron microscope, it was confirmed that the silicon dioxide film was uniformly formed along the fine shape of the polycarbonate optical disk substrate.

Reference Example 1 2 g of γ-aminopropyltriethoxysilane was added to ethanol: isopropyl alcohol: n-pentanol = 5: 3: 2.
A polycarbonate optical disk substrate (having a depth of 0.07 μm, a width of 0.8 μm and a pitch of 1.6 μm) is immersed in a solution (silicon compound concentration of about 1% by weight) dissolved in 250 ml of a mixed solvent (volume ratio), and 15 cm / min. After pulling at the speed of 100
It was dried in a hot air drying oven at ℃ for 1 hour. When the primary coating film was formed on the glass substrate under the same conditions as in the above operation, the film thickness was about 10 nm.

A silicon dioxide film was formed on the polycarbonate optical disk substrate treated with the silane compound as in Example 1.

The thickness of the formed silicon dioxide film was about 80 nm. As a result of analyzing the above film forming portion using ESCA, most of them are SiO ₂
Was confirmed to consist of. It was also confirmed by observation with an electron microscope that the silicon oxide film was formed uniformly along the fine shape of the polycarbonate optical disk substrate.

Reference example 2 Polycarbonate flat plate with flat surface (100 mm in length and width, thickness 1
mm) was treated in exactly the same manner as in Reference Example 1 above to form a silicon dioxide film (about 80 nm).

The obtained silicon dioxide film had a strong adhesive force which did not peel at all in the test of sticking and peeling the cellophane adhesive tape. Further, the above polycarbonate substrate with a silicon dioxide film was immersed in boiling water for 1 hour, but no change was observed in the film, and it was confirmed that the film had good adhesion.

Reference Example 3 Except that 2 g of N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane was used as the silicon compound,
A silicon dioxide film (thickness: 90 nm) was formed in the same manner as in Reference Example 2.

The obtained silicon dioxide film had a strong adhesive force which did not peel at all in the test of sticking and peeling the cellophane adhesive tape. When the above polycarbonate substrate with a silicon dioxide film was immersed in boiling water for 1 hour, no change was observed in the film, and it was confirmed that the film had good adhesion.

From the results of Reference Examples 1, 2, and 3, when forming a coating film on a polycarbonate using a silicon compound having an amino group, an extremely good coating film was obtained even when the silicon compound having an amine group was used alone. It is clear that

Comparative Examples 1, 2, and 3 The following four types of polycarbonate flat plates having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm were prepared.

The one obtained in Reference Example 3 (Reference Example 3) The one obtained by forming only the primary coating in Reference Example 3 (Comparative Example 1). A silicon dioxide coating (100n
(Comparative Example 2) Untreated (Comparative Example 3) These were cut to a size of 60 mmφ and JIS Z-0208 (25 ° C, 9
The moisture permeability was measured by 0% RH). The results are shown in Table 1.

As is clear from Table 1, the silicon dioxide film formed by the precipitation method has a sufficient effect of blocking water vapor, and it has been found that the effect is more than that of the silicon dioxide film formed by the sputtering method.

Example 3, Comparative Example 4, Reference Example 4 The following two types of polycarbonate flat plates having a length of 50 mm, a width of 50 mm and a thickness of 1 mm were prepared.

A silicon dioxide film (90 nm) was formed by the same treatment as in Example 1.
(Example 4) a silicon dioxide film (100 nm) on one side by the sputtering method.
(Comparative Example 4) A silicon dioxide film (90 nm) was formed by the same treatment as in Reference Example 3.
(Thickness) (Reference Example 4) These were left in a thermo-hygrostat kept at 60 ° C. and a relative humidity of 90 ± 5% for 3 weeks, and then the appearance and the adhesion of the coating were examined. While the silicon dioxide formed by the sputtering method (Comparative Example 4) was completely exfoliated and disappeared, the silicon dioxide film formed by the precipitation method (Example 3, Reference Example 4) had no change in appearance and had a strong adhesion. It was a film having.

Examples 4 to 6 A silicon dioxide film (thickness: 90 nm) was formed in the same manner as in Example 1 except that the mixed system of silicon compounds was as shown in Table 2.

Each of the obtained silicon dioxide coatings had a strong adhesive force that did not peel at all in the test in which a cellophane adhesive tape was applied and peeled off. Further, each polycarbonate substrate with a silicon dioxide film was immersed in boiling water for 1 hour, but no change was observed in the film, and it was found that the film had good adhesion.

Comparative Example 5 (see JP-A-61-12734, Example 1) 350 parts of γ-glycidoxypropyltrimethoxysilane,
14 parts water-dispersed colloidal silica (Nissan Chemical Co., Ltd., trade name Snowtex-C, solid content 20%), 9 parts distilled water and
After mixing 3 parts of 1.2N hydrochloric acid aqueous solution and refluxing at 80 ° C. for 4 hours, 57 parts of solvent was distilled off at a distillation temperature of 80 to 90 ° C. To 66 parts of the hydrolyzate solution of γ-glycidoxypropyltrimethoxysilane containing colloidal silica thus obtained, 100 parts of ethyl cellosolve, a curing catalyst and a flow control agent were added a little to prepare a paint. Apply this paint to a polycarbonate optical disk substrate (depth 0.07μm, width 0.8μ
m, having a groove with a pitch of 1.6 μm) by the dipping method, 1
Heat treatment was performed for 60 minutes in a hot air drying oven at 00 ° C. As a result of observing the optical disk substrate on which the primary coating was formed with an electron microscope, the thickness of the primary coating was about 3 μm, and the irregularities on the surface of the disk substrate were completely disappeared.

Comparative Example 6 To 1 part of the hydrolyzate of γ-glycidoxypropyltrimethoxysilane obtained in Comparative Example 5, 100 parts of ethyl cellosolve, a curing catalyst, and a flow control agent were added to prepare a coating material. When this coating material was applied to a polycarbonate flat plate by the dipping method, cissing occurred and it was not possible to obtain a uniform primary coating film on the entire surface.

Comparative Example 7 A mixed solvent of ethyl alcohol: isopropyl alcohol: n-butyl alcohol = 5: 3: 2 (volume ratio) was added to 1 part of the hydrolyzate of γ-glycidoxypropyltrimethoxysilane obtained in Comparative Example 100. A small amount of parts, a curing catalyst, and a flow control agent were added to obtain a paint. When this coating material was applied to a polycarbonate flat plate by the dipping method, cissing occurred and it was not possible to obtain a uniform primary coating film on the entire surface.

Comparative Examples 8, 9 and 10 Ethyl alcohol: isopropyl alcohol: n-butyl alcohol =
It was dissolved in a mixed solvent of 5: 3: 2 (volume ratio).

γ-glycidoxypropyltrimethoxysilane (Comparative Example 8) γ-methacryloxypropyltrimethoxysilane (Comparative Example 9) Vinyltris (β-methoxyethoxy) silane (Comparative Example 10) The concentration of the organosilicon compound in each solution Is all 1% by weight
And

In each solution, respectively, length, width 100nm, a thickness of 1mm polycarbonate plate was immersed, and after pulling up at 15ccm / min, 100
It heat-processed in the hot-air drying furnace of (degree C) for 1 hour.

A silicon dioxide coating (about 1500Å) was formed on the above-mentioned three types of polycarbonate flat plates with the primary coating by the same operation as in Example 1 using a silicon dioxide supersaturated solution of hydrofluoric acid.

When γ-glycidoxypropyltrimethoxysilane (Comparative Example 8) and γ-methacryloxypropyltrimethoxysilane (Comparative Example 9) were used, the obtained silicon dioxide coating was cloudy and had many unevennesses. As a result of microscopic observation, it was found that silicon dioxide was sparsely adhered in the form of particles.

On the other hand, when vinyltris (β-methoxyethoxy) silane (Comparative Example 10) was used, the silicon dioxide film obtained was transparent and uniform, but was easily peeled off in a test in which cellophane adhesive tape was applied and peeled off. It was poor in sex.

As described above, when the primary coating is as thin as several hundreds of angstroms or less, in order to obtain a silicon dioxide coating having a strong adhesive force and excellent durability, it has an amino group when forming the primary coating. It is clear that mixed systems containing silicon compounds must be used.

Example 7, Comparative Example 11 A mixture of 1 g of N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and 1 g of tetraethoxysilane was mixed with ethanol: isopropyl alcohol: n-butyl alcohol = 5: 3: 2 (volume: Ratio) to a solution (silicon compound concentration of about 1% by weight) dissolved in a mixed solvent of 250 ml, length, width 100 mm,
A polycarbonate substrate having a thickness of 1 mm was dipped and pulled up at a speed of 15 cm / min. This polycarbonate substrate is 100 ℃
It was dried for 1 hour in the hot air drying furnace of No. 1 to form a primary coating (Example 3).

N- (β-aminoethyl) -γ-as a silicon compound
The same operation as in Example 7 was carried out except that 2 g of aminopropyltrimethoxysilane was used (concentration of silicon compound: about 1% by weight) to prepare a primary coating on a polycarbonate flat plate (Comparative Example 11).

A 1200Å silicon dioxide film was formed on the above-mentioned two types of primary-coated polycarbonate substrates by a deposition method for 6 hours.

As a result, when a mixture of N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and tetraethoxysilane was used for the formation of the primary coating (Example 7), it was uniformly oxidized by the precipitation method. Whereas a silicon coating was obtained, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane was used alone (Comparative Example 11).
Was obtained with a lot of white turbidity. Observation of this cloudy portion with an electron microscope revealed that silicon dioxide was sparsely adhered to the particles.

From the results of Example 7 and Comparative Example 11, it is clear that tetraethoxysilane improves the film forming property of the silicon dioxide film by the precipitation method. Not limited to tetraethoxysilane, methyltriethoxysilane, vinyltris (β
The silicon compound represented by the general formula (I) such as -methoxyethoxy) silane gave good results in the film forming property of the silicon dioxide film by the precipitation method.

[Effects of the Invention] As described in detail above, the method for producing a silicon dioxide-coated polycarbonate molded article according to the present invention comprises a silicon compound having an amino group on the surface of the polycarbonate molded article and a silicon compound represented by the general formula (I) or a compound thereof. By coating a coating solution containing a hydrolyzate in a specific ratio and drying and curing, a very thin silicon-containing coating having good adhesion is coated as a primary coating, and the first coating is further formed thereon. According to the method of the present invention, the silicon dioxide coating having good adhesion is formed, and the durability is far higher than that of a silicon dioxide coating formed directly on the surface of a polycarbonate molded body by vapor deposition or sputtering. It is possible to form a film having good quality.

In the coating method for forming the primary coating, a dilute solution of a silicon compound can be used as a coating solution, and the silicon compound diffuses into the polycarbonate, so that an optical disk substrate having a fine irregular shape can be used. A thin film can be coated without damaging the shape.

After the formation of the primary film, the film is formed by depositing silicon dioxide by bringing it into contact with a solution. Therefore, it is possible to form a silicon dioxide film that follows the irregular shape of the surface of a polycarbonate optical disk substrate or the like.

Both the front and back sides can be formed simultaneously, and the obtained silicon dioxide film not only has the effect of blocking the transmission of water vapor, oxygen, etc., but also has the effect of improving the wear resistance of the laser incident surface of the optical disc. I have it.

And so on.

[Brief description of drawings]

FIG. 1 is a system explanatory view of the silicon dioxide film manufacturing apparatus used in the examples. 1 ... Outer tank, 2 ... Inner tank, 3 ... Water, 4 ... Heater, 5 ... Stirrer, 6 ... Inner tank front part, 7 ... Inner tank middle part, 8 ... Inner tank rear part, 9 ... Polycarbonate molding, 10 ... Circulation pump, 11 ... Filter, 12 ... Metal aluminum plate, 13 ... Stirrer.

Claims (3)

[Claims] 1. A polycarbonate molded body is coated with an organic silicon compound to cure it to form a primary coating, and the polycarbonate molded body with the primary coating is brought into contact with a supersaturated hydrosilicic acid solution of silicon dioxide. In the method for producing a silicon dioxide-coated polycarbonate molded product, which comprises forming a silicon dioxide film on a primary film, the primary film is formed from a group consisting of a silicon compound represented by the following general formula (I) and a hydrolyzate thereof. A coating liquid containing at least one selected silicon compound and a silicon compound having an amino group, wherein the content of the silicon compound having an amino group is 0.2% by weight or more, and the total concentration of the silicon compounds is 5%. A method for producing a silicon dioxide-coated polycarbonate molded article, which is characterized by being formed by applying a coating liquid of not more than wt% and drying. ▲ R ¹ _n ▼ Si (R ² ) _4-n (I) (In the formula, R ¹ is a hydrocarbon group having 2 or less carbon atoms such as ethyl group and vinyl group, or mercapto group, and 3 carbon atoms having a hydroxyl group. The following organic groups, R ² is one or more bonding groups selected from an alkoxy group, an alkoxyalkoxy group, an acetoxy group and a chlorine element, and n is 0 or 1.) 2. The condition for forming the primary coating is 5 to 100 n when the coating is formed on a glass substrate under the same conditions.
Claim 1 which is a condition under which a m-thick coating is formed.
Item 10. A method for producing a silicon dioxide-coated polycarbonate molded article according to item. 3. A silicon compound having an amino group is γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and N-.
The method for producing a silicon dioxide-coated polycarbonate molded article according to claim 1 or 2, wherein the number is one or more selected from the group consisting of (β-aminoethyl) -γ-aminopropyldimethoxysilane. .