JP3006065B2 - Silicon dioxide coated plastic molded article and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plastic molded product whose surface is covered with a silicon dioxide film having excellent durability and a method for producing the same.

[Related Art] In recent years, as a silicon dioxide film forming method, there is no need for a vacuum system capable of forming a film at a low temperature. A method of forming silicon dioxide on the surface of a substrate by bringing a substrate into contact with an aqueous solution of hydrosilicofluoric acid in a supersaturated state of silicon (hereinafter, referred to as
Attention has been paid to "precipitation method" (for example, JP-A-60-33233 and JP-A-62-20876).

In particular, regarding a method of forming a silicon dioxide film on a plastic molded product by a deposition method, a plastic molded product is coated with an organosilicon compound or a hydrolyzate thereof and cured to form a primary film, and then a primary method is performed by a deposition method. A method of forming a silicon dioxide film on the film is known (for example,
61-12734). Here, it is described that an organosilicon compound or a hydrolyzate thereof functions as a primer for obtaining silicon dioxide as a transparent and uniform film with good adhesion by a deposition method on a plastic surface.

Further, in order to improve the adhesion durability of the silicon dioxide film, a method is known in which after a plastic molded body is coated with a silyl peroxide compound, a silicon dioxide film is formed on the silyl peroxide compound coating layer by a deposition method. (JP-A-2-88648). This is to improve the adhesion durability of silicon dioxide by forming a chemical bond between the plastic substrate and the silicon dioxide film via a primer by the reaction of free radicals generated by the thermal decomposition of silyl peroxide. is there.

[Problems to be Solved by the Invention] However, since the heat treatment needs to be performed at a temperature higher than the temperature at which silyl peroxide is thermally decomposed after the formation of the silicon dioxide film, there is a problem that cracks are easily generated in the silicon dioxide film. there were.

Further, depending on the conditions of the deposition method, there was a problem that a silicon dioxide film could not be obtained, or even if it was obtained, the film was unevenly clouded.

[Means for Solving the Problems] The present invention solves the above-mentioned conventional problems, and covers the advantages of plastic and glass by covering a plastic molded product with a silicon dioxide film having excellent durability and uniform thickness. It is intended to provide a method for producing a combined substrate.

The present invention provides: a) a plastic molded body; b) one or more coating layers of a silyl peroxide compound represented by the general formula (I); R ¹ _m Si (OOR ² ) _4-m (I) R ¹ may be the same or different from each other, and may be 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 an organic group having chlorine. And R ² may be the same or different from each other, and represents an alkyl group, an acyl group or an arylalkyl group, and m represents an integer of 0 to 2.

c) One or two silicon compounds represented by the general formula (II)
A coating layer composed of at least one kind of partial hydrolysate, having a thickness of 0.03 to 3 μm, and R ³ _n Si (OR ⁴ ) _4-n (II) wherein R ³ may be the same or different from each other; 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 an organic group having chlorine, and R ⁴ may be the same or different from each other It often represents an alkyl group, an acyl group or an alkoxyalkyl group, and n is 0 or 1.

d) a silicon dioxide film formed by contacting the layer c) with an aqueous solution of hydrosilicofluoric acid in a supersaturated state of silicon dioxide, laminated in the order of a), b), c) and d); And g) a silicon dioxide-coated plastic molded body which has been heat-treated under the condition that the silyl peroxide compound is thermally decomposed after the layer is coated and before the layer d) is coated. is there.

 Hereinafter, the present invention will be described in detail.

The plastic molded body used in the present invention is not particularly limited. Thermosetting resins represented by thermoplastic resins and elastomers represented by sulfones, aromatic polyesters, polyetherketones, polyimides, polyacrylonitriles, etc., and molded products made of polymer blends thereof, polydiethylene glycol bisallyl carbonate, phenol resins, etc. It is a resin molded article. The shape and size of the molded body are arbitrary.

In the present invention, the silyl peroxide compound represented by the general formula (I) used for forming the layer b) includes vinyltris (t-butylperoxy) silane, vinyltris (cumeneperoxy) silane, and vinyltris (acetylperoxy). ) Silane, vinyl tris (benzoyl peroxy) cyan, vinyl tris (lauroyl peroxy) silane, γ-glycidoxypropyl tris (t-butyl peroxy) silane, γ-glycidoxypropyl tris (cumene peroxy) silane, γ -Glycidoxypropyltris (acetylperoxy) silane, γ-glycidoxypropyltris (benzoylperoxy) silane, γ-glycidoxypropyltris (lauroylperoxy) silane, γ-methacryloxypropyltris (t- Butyl Perot B) silane, γ-methacryloxypropyltris (cumeneperoxy) silane, γ-methacryloxypropyltris (acetylperoxy) silane, γ-methacryloxypropyltris (benzoylperoxy) silane, γ-methacryloxypropyltris ( Lauroylperoxy) silane, and the like. One of these silicon compounds may be used alone, or two or more thereof may be used in combination.

Examples of the silicon compound represented by the general formula (II) used for forming the layer c) include tetramethoxysilane, tetraethoxysilane, tetraacetoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and vinyltris (β-methoxy). Ethoxy) silane, vinyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl)-
γ-aminopropyltrimethoxysilane, γ-fluoropropyltrimethoxysilane, and the like. These hydrolysates include those obtained by substituting a part or all of an alkoxy group, an alkoxyalkoxy group, and an acetoxy group in a silicon compound represented by the general formula (II) with a hydroxyl group. Include some of which are naturally condensed. These hydrolysates can be easily obtained by hydrolysis in a mixed solvent such as water and alcohol in the presence of an acid.

These hydrolysates may be used alone or in combination of two or more, but when two or more are used in combination,
It is preferable to use a mixture of two or more silicon compounds represented by the general formula (II) and co-hydrolyzed.

In the present invention, a coating solution is prepared by dissolving one or more of the silyl peroxide compounds represented by the above general formula (I) in various organic solvents, applied to a plastic molded product, and dried to obtain b. ) Form a layer. The concentration of the silyl peroxide compound can be determined as appropriate, but it is necessary to adjust the solution, to facilitate the coating operation, and to obtain the desired thickness b).
From the viewpoint of obtaining a layer, usually, the range of 5 to 50% by weight is preferable.

As the coating method for forming the above-mentioned b) layer, a commonly used dipping method, spin coating method, flow coating method, bar coder method, doctor blade method,
Any of a spraying method, a reverse roll coater method, a gravure roll coater method and the like can be adopted. After coating, the coating is dried and cured at a temperature at which the silyl peroxide compound does not thermally decompose.

B) thus obtained on plastic moldings
The thickness of the layer is not particularly limited, but is usually 0.1 to 10 μm.
m, preferably about 0.5 to 5 μm. If the thickness of the coating layer is too small, the adhesion of the silicon dioxide film obtained by the deposition method tends to decrease, which is not appropriate. On the contrary, if it is too large, it is uneconomical.

The coating liquid containing one or more partial hydrolysates of the silicon compound represented by the general formula (II) is applied to the plastic molded body having the layer b) formed in the above-described manner, and dried to obtain c). Form a layer. Here, the layer c) is formed in order to improve the film forming property of the silicon dioxide film by the deposition method.

When silicon dioxide coating is applied by a deposition method to a plastic molded body having only the layer b) formed without forming the layer c), it is difficult to obtain a desired film thickness and the film thickness may be reduced. Further, when the film is formed by the deposition method in a state where only the layer b) is formed, silicon dioxide particles existing near the liquid surface of the hydrosilicofluoric acid aqueous solution in a supersaturated state of silicon dioxide adhere to the substrate when the substrate is immersed. These particles are taken into the obtained silicon dioxide film, and unevenly clouded portions are observed or cause deterioration in the film quality of the silicon dioxide film.

By forming the layer c), a desired film thickness can be easily obtained, and the above-mentioned disadvantages of film quality deterioration can be solved. This has no effect unless the silicon compound represented by the general formula (II) is hydrolyzed and used.

The coating solution used is a partially hydrolyzed product of the silicon compound represented by the general formula (II) in terms of R ³ _n SiO _{2 -n / 2,}
^{If the amount is} less than ^-3 mol /, the above effect is reduced, so that it is not appropriate.

As the coating method for forming the above-mentioned c) layer, a commonly used dipping method, spin coating method, flow coating method, bar coder method, doctor blade method,
Any of a spraying method, a reverse roll coater method, a gravure roll coater method and the like can be employed.

The thickness of the layer c) provided on the layer b) on the plastic molded body in this way is usually about 0.03 to 3 μm, preferably about 0.1 to 1 μm. If the thickness of the coating layer is too small, the adhesion of the silicon dioxide film obtained by the deposition method tends to decrease, which is not appropriate. On the contrary, if it is too large, it is uneconomical.

In the present invention, the plastic molded body on which the b) layer and the c) layer obtained above are formed is subjected to a heat treatment. By this heat treatment, the silyl peroxide compound is decomposed to generate free radicals, and due to the action of the free radicals, a chemical bond is generated, and the surface of the plastic molded body is c).
The layer is tightly adhered. This heat treatment also promotes the curing of layer c).

The heat treatment temperature and time can be determined by the heat deformation temperature of the plastic molded article used and the half-life of the silyl peroxide compound. For example, in the case of polycarbonate and polyacrylate, etc.
Heat treatment may be performed for 2 hours, and in the case of a polyetherimide molded article having good heat resistance, heat treatment may be performed at 130 to 170 ° C. for 20 to 50 minutes. Generally, heat treatment at about 100 ° C. for 1 to 2 hours is sufficient.

As a method of the heat treatment, it is preferable to heat in a hot air dryer because of easy operation.

In the present invention, the plastic molded body having the b) layer and the c) layer firmly adhered thereto by heating is then brought into contact with a supersaturated aqueous solution of hydrosilicofluoric acid of silicon dioxide,
c) Form a silicon dioxide coating on the layer.

As an aqueous solution of hydrosilicofluoric acid in a supersaturated state of silicon dioxide (hereinafter abbreviated as “treatment liquid”), an aqueous solution of hydrosilicofluoric acid is mixed with silicon dioxide (silica gel, Aerosil, silica glass, and other substances containing silicon dioxide). ) Is dissolved, and water or a reagent (boric acid, aluminum chloride, metallic aluminum, etc.) is added, or the temperature of the processing solution is increased to make the silicon dioxide supersaturated.

In the present invention, the concentration of the treatment liquid to be brought into contact with the plastic molded body on which the layer b) and the layer c) are formed is from 2 to
4 mol / is preferable, and in particular, after saturating silicon dioxide in an aqueous solution of hydrosilicofluoric acid at a concentration higher than 4 mol /, dilute with water to
A concentration of 4 mol / is desirable because the film formation speed is high and the film can be formed efficiently.

In addition, the treatment liquid is (a) an additive aqueous solution such as boric acid or aluminum chloride is continuously added and mixed even at the time of contact with the molded body, and a metal such as aluminum is dissolved and mixed. A high-concentration aqueous solution of hydrosilicofluoric acid, which is continuously saturated with silicon dioxide, and water are added and mixed, and the temperature is temporarily cooled to saturate the silicon dioxide, and thereafter, the temperature is increased again. (B) It is preferable that 3% or more of the total processing liquid per minute is filtered and returned by a filter.

Here, at the time of contact, it is preferable to continuously add and mix an aqueous solution such as boric acid or dissolve and mix a metal such as aluminum in order to improve the film formation speed. In the case of boric acid, its addition amount is preferably in the range of 5 × 10 ⁻⁴ mol / Hr to 1 × 10 ⁻³ mol / Hr per 1 mol of hydrosilicofluoric acid in the treatment liquid. amount of dissolution when dissolving in the range of ^{1 × 10 -3 mol / Hr~4 ×} 10 -3 mol / Hr with respect hydrosilicofluoric acid 1mol in the treatment liquid is preferred.

Circulating a treatment liquid of 3% or more is effective for continuously obtaining a uniform coating, and filtering the treatment liquid with a filter is preferable for obtaining a coating having no irregularities.

When the treatment liquid is put in the immersion tank and brought into contact with the molded body, it is necessary to make the treatment liquid flow as a laminar flow on the surface of the molded body during immersion to obtain a uniform coating without unevenness. It is effective for

FIG. 1 is a system diagram of a silicon dioxide film manufacturing apparatus used in the present invention.

In FIG. 1, the immersion tank comprises an outer tank 1 and an inner tank 2, and the space between the inner tank 1 and the outer tank 2 is filled with water 3. The water is heated by a heater 4 so as to have a constant temperature, and is stirred by a stirrer 5 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, and each part is filled with an aqueous solution of hydrosilicofluoric acid 6.5 having a predetermined concentration obtained by dissolving and saturating silicon dioxide using industrial silica gel powder as a source of silicon dioxide. It is. Here, the three-way cocks 13a, 13
a ', 13b and 13b' are adjusted, and the circulation pump 12a is operated to extract a predetermined amount of the reaction solution in the rear portion 8 of the inner tank, and the filter 11
The treatment liquid circulation which was filtered in a and returned to the inner tank 6 was started.

Here, the mesh of the filter 11a is 1.5 μm,
The circulation flow rate of the reaction solution was set to 520 ml / min (the circulation flow rate was about 8% / min because the total amount of the reaction solution was 6.5).

After that, three 50 mm long, 50 mm wide, 3 mm thick Al plates 15
It was immersed in the rear part 8 of the inner tank, and the stirrer 16 was operated to accelerate the dissolution of the Al plate.

By maintaining this state for 16 to 30 hours, the reaction solution became a treatment solution having an appropriate degree of saturation of silicon dioxide (a silicon dioxide film can be formed).

When the reaction liquid has the ability to form silicon dioxide,
Even in the reaction liquid, silicon dioxide is generated as particles, grows, and is eventually filtered by the filter 11a, causing clogging of the filter. This tendency was observed 30 to 50 hours after the addition of Al, leading to a decrease in the circulation amount. Therefore, after returning the reaction solution in the pipe and the filter 11a to the inner tank 2,
The three-way cocks 13a and 13 are circulated so that the reaction solution is circulated in the inner tank rear part 8 → the filter 11b → the circulation pump 12a → the inner tank front part 6.
When a ', 13b, and 13b' were set and the circulation of the reaction solution was started again, the circulation amount of the reaction solution was restored to 520 ml / min.
Here, the mesh of the filter 11b is 1.5 μm like the filter 11a.

In this state, the circulation pump 12b is operated, and the 5% hydrofluoric acid aqueous solution 10 is supplied to the washing liquid tank 9 → the filter 11a → the circulation pump 1
The filter 11a clogged by circulating in the order of 2b → the washing liquid tank 9 was washed and regenerated.

According to the above procedure, each time the filter tends to be clogged, the three-way cocks 13a, 13a ', 13b, and 13b' are adjusted and the operation of switching the filter is performed. Chubu 7
, A silicon dioxide film could be continuously obtained.

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 as long as the gist is not exceeded.

Examples 1 to 6 Polycarbonate flat plate (length, width 100 mm each, thickness 1 mm)
The n of the various silyl peroxide compounds shown in Table 1
Hexane solution (concentration 10% by weight)
The layer b) was formed by drying at a temperature of 3 ° C. for 3 minutes. The thickness of the layer b) after drying was about 1 μm.

Then, b) on the polycarbonate plate on which the layer was formed,
An isopropyl alcohol solution of a hydrolyzate of a silicon compound shown in Table 1 was applied by an immersion method to form a layer c).
By heating at 0 ° C. for 1 hour, the silyl peroxide compound was thermally decomposed. The thickness of the layer c) after the thermal decomposition was about 0.1 μm in each case.

The solution of the hydrolyzate of the silicon compound 100 g of the compound, 100 g of distilled water and 0.5 ml of 0.1 N hydrochloric acid were mixed and stirred, and 20 g of the obtained homogeneous solution was diluted with 200 ml of isopropyl alcohol to prepare a mixture.

A polycarbonate flat plate having the above-mentioned layers b) and c) laminated in this order was immersed in the middle portion 7 of the inner tank of the silicon dioxide film production apparatus shown in FIG. 1 and then held for 80 minutes to form a silicon dioxide film.

The concentration of the hydrofluoric acid aqueous solution circulating in the silicon dioxide film manufacturing apparatus was 3.2 mol /, and the heater 4 was adjusted so that the temperature at the time of film formation was 35 ° C.

As described above, a silicon dioxide film having excellent transparency uniformity was obtained in the form of a polycarbonate plate. When the film thickness of the film was examined, it was about 0.1 μm.

All of the above silicon dioxide coatings had a strong adhesive force which was not peeled off at all in a test in which a cellophane adhesive tape was applied and peeled off. Further, when immersed in boiling water for 1 hour, there was no change in the adhesive force.

Examples 7 to 12 Except that a polyetherimide flat plate (100 mm in length and width, 1.6 mm in thickness) was used as a plastic molded body, and the pyrolysis of a silyl peroxide compound was performed at 150 ° C. for 30 minutes. In the same manner as in Example 4, a silicon dioxide-coated polyetherimide flat plate was obtained. All of the silicon dioxide coatings were excellent in transparency and uniformity and had a strong adhesive force which was not peeled off at all in a test in which a cellophane adhesive tape was applied and peeled off.

Comparative Examples 1 and 2 A silicon dioxide film was formed in the same manner as in Examples 1 to 6, except that a polycarbonate flat plate having only the layer b) without forming the layer c) was used.

However, in each case, the obtained silicon dioxide film was cloudy and had many irregularities.

From the results of Examples 1 to 6 and Comparative Examples 1 and 2, it is clear that the formation of the layer c) has a favorable effect on the uniformity of the silicon dioxide film formed by the deposition method.

Comparative Example 3 The same procedure as in Comparative Example 1 was carried out except that the concentration of the hydrosilicofluoric acid aqueous solution circulating in the silicon dioxide film production apparatus was 1.5 mol / b. Was formed.

Although the obtained silicon dioxide film was excellent in transparency uniformity, b) when heated at 110 ° C. for 1 hour to decompose the silyl peroxide compound constituting the layer, cracks were generated on the entire surface of the silicon dioxide film. did.

[Effects of the Invention] As described above in detail, the method for producing a silicon dioxide-coated plastic molded article of the present invention provides a method for producing a coating layer (b) of a silyl peroxide compound represented by the general formula (I) on the surface of the plastic molded article. After that, a coating layer (c) layer of a hydrolyzate of a silicon compound represented by the general formula (II) is formed thereon,
By thermally decomposing the silyl peroxide compound to form a chemical bond between the plastic substrate and the c) layer via the b) layer, and further forming a silicon dioxide film having good adhesion with the c) layer thereon. According to the method of the present invention, the formation of the layer c) improves the film forming property of silicon dioxide by the deposition method, and a transparent and uniform silicon dioxide film can be obtained.

Since there is no heat treatment after the silicon dioxide coating, no cracks occur in the silicon dioxide coating.

The obtained silicon dioxide film is excellent in denseness and can improve various drawbacks (for example, water absorption, gas permeability and gas release) of plastic.

And other excellent effects.

[Brief description of the drawings]

FIG. 1 is a system explanatory diagram of a silicon dioxide film manufacturing apparatus used for carrying out the present invention. DESCRIPTION OF SYMBOLS 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 ... Cleaning liquid Tank, 10 5% HF aqueous solution 11 Filter, 12 Circulating pump 13 Three-way cock 14 Plastic molded body 15 Al plate, 16 Stirrer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-38443 (JP, A) JP-A-2-88648 (JP, A) JP-A-61-12732 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C08J ⁷ /00-7/18 B05D 7/02 B32B 9/00

Claims (2)

(57) [Claims] A) a plastic molded article; b) one or more coating layers of a silyl peroxide compound represented by the general formula (I); R ¹ _m Si (OOR ² ) _4-m (I) In the formula, R ¹ may be the same or different from each other, and may be 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 an organic group having chlorine, R ² may be the same or different from each other, and represents an alkyl group, an acyl group or an arylalkyl group, and m is Shows an integer of 0 to 2. c) One or two silicon compounds represented by the general formula (II)
A coating layer composed of at least one kind of partial hydrolysate, having a thickness of 0.03 to 3 μm, and R ³ _n Si (OR ⁴ ) _4-n (II) wherein R ³ may be the same or different from each other; 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 an organic group having chlorine, R ⁴ may be the same or different from each other, and represents an alkyl group, an acyl group or an alkoxyalkyl group, and n is It is 0 or 1. d) a silicon dioxide film formed by contacting the layer c) with an aqueous solution of hydrosilicofluoric acid in a supersaturated state of silicon dioxide, laminated in the order of a), b), c) and d); A) a silicon dioxide-coated plastic molded body that has been heat-treated under conditions where the silyl peroxide compound is thermally decomposed after the layer is coated and before the layer d) is coated. A) on the surface of a plastic molded body; b) R ¹ _m Si (OOR ² ) _{4-m of the} general formula (I) wherein R ¹ may be the same or different from each other; A hydrocarbon group of a number 1 to 6, a vinyl group, a methacryloxy group,
An epoxy group, an amino group, a mercapto group, an organic group having fluorine or an organic group having chlorine, R ² may be the same or different from each other, and represents an alkyl group, an acyl group or an arylalkyl group, and m is Shows an integer of 0 to 2. One or two silyl peroxide compounds represented by
And c) a general formula (II) R ³ _n Si (OR ⁴ ) _4-n (II) wherein R ³ may be the same or different from each other and have 1 to 6 carbon atoms. Hydrocarbon group, vinyl group, methacryloxy group,
An epoxy group, an amino group, a mercapto group, an organic group having fluorine or an organic group having chlorine, R ⁴ may be the same or different from each other, and represents an alkyl group, an acyl group or an alkoxyalkyl group, and n Is 0 or 1. Forming a layer of one or more partial hydrolysates of a silicon compound represented by the formula (b) on the layer (b), followed by a heat treatment under the condition that the silyl peroxide compound is thermally decomposed; 2. The method of claim 1 wherein said step (c) is supersaturated and comprises contacting said aqueous solution of hydrofluoric acid having a concentration of 2-4 mol / l with said layer c) to form a silicon dioxide coating thereon. A method for producing a silicon-coated plastic molded body.