JPH0578614A - Coating material and method for coating using the same - Google Patents

Abstract

PURPOSE:To obtain the subject material capable of providing transparent cured acrylic product films having a high surface hardness by dissolving a radical copolymer having alkoxysilyl groups in side chains, a metallic alkoxide, etc., in an organic solvent and adding a Lewis acid to the resultant solution. CONSTITUTION:The objective material is obtained by dissolving (A) 1-60wt.% radical polymer [having 50000-300000 number-average molecular weight (expressed in terms of PS)], expressed by formula I [R is H or 1-5C alkyl ; R' is 1-5C alkyl; (l) is 1-3; m/n is (99/1) to (80/20) molar ratio] and having alkoxysilyl groups in side chains and (B) 99-40wt.% of (i) a metallic alkoxide expressed by formula II (R<1> is H, 1-5C alkoxy, phenoxy, phenyl or 1-5C alkyl; R<2> is 1-5C alkyl or phenyl; M is Si, Ti, Sn or Zr; (n) is 1-4) and/or (ii) a metallic chelate compound expressed by formula III (M' is Ti, Sn or Zr; R<3> is 1-5C alkyl; Acac is acetylacetonates) in an organic solvent and adding a Lewis acid to the resultant solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for obtaining a transparent acrylic cured film having a high surface hardness and a coating method thereof.

[0002]

2. Description of the Related Art As a conventional coating method using an acrylic thermosetting material, there is known a method in which an acid, a base, an organometallic catalyst or the like is added to a polymer having an alkoxysilane in its molecular chain. ing. For example, JP-A-60-675
No. 53, JP-A-63-108049 and JP-A-1-129018 disclose a transparent thermosetting coating material having an alkoxysilane such as methacryloxypropyltrimethoxysilane in the side chain. Is disclosed.

[0003]

However, the film obtained from the above-mentioned conventional acrylic resin material has a low surface hardness, and thus has a problem in scratch resistance. Furthermore, there are problems such as shrinkage of the film due to uneven curing during heat curing and a decrease in transparency during heat curing.

[0004]

In view of the above circumstances, the present inventor has conducted extensive studies to solve the above-mentioned problems of the prior art, and as a result, an acrylic cured product having no curing unevenness and having a transparent and high surface hardness. The present invention has been completed by finding a coating material for obtaining a film.

That is, the present invention has the following general formula

[0006]

[Chemical 4] (In the formula, R is hydrogen or an alkyl group having 1 to 5 carbon atoms,
R'represents an alkyl group having 1 to 5 carbon atoms, l is 1 to 3,
Radical copolymer having an alkoxysilyl group represented by m / n in a molar ratio of 99/1 to 80/20) in the side chain (number average molecular weight 50,000 to 300,000: polystyrene conversion) [1] 1 to 60% by weight, The following general formula

[0007]

[Chemical 5] (In the formula, R ¹ represents hydrogen, an alkoxy group having 1 to 5 carbon atoms or a phenoxy group, an alkyl group having 1 to 5 carbon atoms or a phenyl group, and R ² represents an alkyl group having 1 to 5 carbon atoms or a phenyl group. , M is Si, Ti, Sn or Zr,
n represents an integer of 1 to 4) and / or a metal alkoxide [2] represented by the following general formula:

[0008]

[Chemical 6] (M ′ represents Ti, Sn or Zr, R ³ has 1 carbon atom
~ 5 alkyl group, Acac represents acetylacetonate) [3] 99-4
A coating material prepared by dissolving 0% by weight in an organic solvent and adding a Lewis acid thereto, and applying this material on a substrate, heat-curing it and three-dimensionally crosslinking it,
At least one metal-oxygen bond (provided that the metal is S
i, Ti, Sn or Zr), the metal species of which is 15% by weight or more based on the total amount of the cured product, and the degree of crosslinking is 70%.
The present invention relates to a coating method characterized by forming an acrylic transparent cured product film.

The radical copolymer [1] having an alkoxysilyl group in the side chain used in the present invention is preferably acrylic acid, methyl acrylate, ethyl acrylate, methacrylic acid, methyl methacrylate or ethyl methacrylate. At least one compound selected, and preferably 3-methacryloxypropyltrimethoxysilane, 3-
Methacryloxypropyltriethoxysilane, 3-methacryloxypropyltributoxysilane, 3-methacryloxypropylpropoxysilane, 3-methacryloxypropylisopropoxysilane, 2-methacryloxyethyltrimethoxysilane, 2-methacryloxyethyltriethoxysilane , 2-methacryloxyethyltributoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethyltributoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3 -Acryloxypropyltributoxysilane, 2-acryloxyethyltrimethoxysilane, 2-acryloxyethyltriethoxysilane,
At least one compound selected from 2-acryloxyethyltripropoxysilane, 2-acryloxyethyltributoxysilane, acryloxymethyltrimethoxysilane, acryloxymethyltriethoxysilane, and acryloxymethyltributoxysilane. It is a radical copolymer, the composition of which is a molar ratio of 99: 1.
It is preferably in the range of 80:20.

Such a copolymer [1] can be obtained by a known synthesis method using a known polymerization initiator, but a solution radical polymerization method is preferable. In the polymerization, benzene, toluene, aromatic hydrocarbons such as xylene, hexane, heptane, aliphatic hydrocarbons such as cyclohexane, ethyl acetate, ester-based ethylene glycol monoethyl ether acetate, acetone, methyl ethyl ketone, Methyl isobutyl ketone, ketone system such as cyclohexanone, methanol, ethanol
, Isopropanol, n-butanol, isobutanol
An alcohol-based or ether-based solvent such as alcohol, diglyme or ethylene glycol monoethyl ether can be used.

The number average molecular weight of the copolymer [1] is determined by gel permeation chromatography (GPC).
The polystyrene conversion is preferably 50,000 to 300,000, more preferably 100,000 to 20,000.
It is 0.

The monomer concentration during the polymerization is 0.5 to 5
mmol / ml is preferred, but more preferably 0.8-
It is 1.5 mmol / ml.

The polymerization temperature is preferably 60 to 80 ° C, more preferably 65 to 75 ° C. Polymerization time is 4-8
Although it is about an hour, it is more preferably 6 to 7 hours.

At least one of the following compounds [2] and [3] (hereinafter referred to as a cross-linking agent) is added to the organic solution of the copolymer [1] thus obtained to obtain a Lewis acid. When the reaction is carried out in the presence of a crosslinking accelerator such as, for example, at least one metal-oxygen bond (metal is Si, T
A three-dimensional stitch is formed by i, Sn or Zr), and the obtained coat film is crosslinked while maintaining transparency, and the surface hardness can be remarkably improved as compared with the conventional one.

As the cross-linking agent [2] used, tetramethoxysilane, tetraethoxysilane, tetraphenoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, ethyltrimethoxysilane, ethyltriphenoxysilane, phenyltrimethoxysilane, Alkoxysilanes such as phenyltriethoxysilane and phenyltriphenoxysilane, tetrabutyl titanate,
Examples thereof include titanic acid esters such as tetraisopropyl titanate, tin alkoxides such as tin methoxide and tin ethoxide, zirconium alkoxides such as zirconium ethoxide, zirconium isopropoxide and zirconium butoxide. Further, as the cross-linking agent [3], titanium alkoxybis acetylacetonate,
Examples thereof include chelate compounds such as tin acetylacetonate dibromide and zirconium acetylacetonate. These crosslinking agents used for crosslinking may be used alone or in combination of two or more.

The content of the crosslinking agent used in the copolymer [1] is preferably such that the metal content is 15% by weight or more based on the total weight of the obtained film. In that case, the amount of the crosslinking agent added to the copolymer [1] is
40 to 99% by weight is preferable. When the amount of the cross-linking agent added is less than 40% by weight, there is almost no improvement in the hardness of the film, and when it is more than 99% by weight, the hardness of the obtained film reaches the ceiling. Particularly, when the addition amount is 50 to 60% by weight, the surface hardness is remarkably improved. Furthermore, the shrinkage phenomenon of the film during curing is not seen.

Further, the amount of the cross-linking agent can be arbitrarily changed and the transparency can be maintained as long as the content of the metal in the obtained film is in the range of 15 to 60% by weight.

The amount of the organic solvent is such that the concentration of the mixture of the copolymer [1], the cross-linking agent [2] and / or [3] is 0.1-3.
It is preferable to add it so as to be 0 g / ml.

The process leading to the formation of the film can be easily achieved by using the known sol-gel method.

That is, a Lewis acid is added to an organic mixed solution composed of the copolymer [1], the cross-linking agent [2] and / or [3] and stirred at room temperature to obtain a stable sol in 20 to 30 minutes. A solution is obtained. Further, the solution is spin-coated (or dip-coated) on various substrates and heated in the atmosphere, and a transparent and extremely high surface hardness film is obtained through the sol-gel transition. The type of base material used in the coating method is plastic,
Inorganic and organic materials such as wood, metal and glass can be used.

The temperature range for cross-linking and hardening is 5
0 to 190 ° C, more preferably 80 to 130 ° C
Is. The time required for curing is about 1 to 2 hours,
The higher the curing temperature, the shorter the time required. At this time, it is essential that the crosslink density of the film is always 70% or more. As the Lewis acid used at the time of curing, a protic acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid or acetic acid is preferable.

In this way, the thermal crosslinking reaction is carried out in a uniform state, and 3
The film obtained by dimensional stitching is in a completely compatible state,
Shows high transparency. Furthermore, it shows the properties superior to those predicted from the properties and composition ratio of each polymer.

[0023]

As described above, according to the present invention, high hardness transparent coating of inorganic and organic materials is possible.

[0024]

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.

The film is formed by using the above sol solution with PM.
Spin coating was performed on the MA substrate and thermal crosslinking was performed. The surface hardness of the coating is JIS-K54.
It was evaluated according to the pencil hardness test described in 01 (the surface hardness of the PMMA substrate before coating was evaluated as 3H).

The thickness of the coating was measured from the fracture surface using a scanning electron microscope. The weight of the crosslinking agent contained in the coating was calculated from the atomic absorption of the firing residue after the coating was peeled from the substrate and baked at 1000 ° C.

The transparency of the film is determined by UV of 300 to 900 nm.
-Judging from VIS absorption. The degree of crosslinking of the film was calculated from the absorption of silicon NMR.

Example 1 Methyl methacrylate (8.56 g, 85.5 mmo)
l), 3-methacryloxypropyltrimethoxysilane (1.12 g, 4.5 mmol), azobisisobutyronitrile (AIBN) (15 mg, 90 μmol), and diglyme (80 ml) were placed in a sealed tube and deaerated. Then, the sealed tube was shaken and reacted at 70 ° C. for 6 hours in a constant temperature bath.

After the reaction was completed, the sealed tube was opened and the reaction solution was 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) The substrate was spin-coated and then transferred to an oven and heated at 130 ° C. for 1 hour to form a transparent thin film on the substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 150,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating is observed with a scanning electron microscope,
The surface hardness was about 2 μm and the surface hardness was 7H. Baking coating
The resulting ash was subjected to atomic absorption spectrometry and
Almost all of the obtained crosslinking agent was consumed in the crosslinking reaction.
It was Si contained in the total weight of the coating is 26.4% by weight.
there were. Coating solid Si-NMR (97.3 MHz; Po
From the spectrum of (ridimethylsiloxane)
The collection peak is δ-48.7ppm, δ-57.2ppm,
It can be read as δ-66.2 ppm and δ-75.2 ppm,
Each absorption peak intensity ratio is 0.01: 9.99:
It was 72:18. Table 1 shows the attribution of these absorptions.
You

[0033]

[Table 1] From the attribution of these peaks and the absorption intensity, the degree of crosslinking of this coating is 0.01 × 1/4 + 9.99 × 2/4 + 72 ×
It was found that 3/4 + 18 × 4/4 = 77%.

Example 2 Methyl methacrylate (8.56 g, 85.5 mmo)
l), 3-methacryloxypropyltrimethoxysilane (1.12 g, 4.5 mmol), AIBN (15 m
g, 90 μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Next, shake the sealed tube at 70 ° C.
The reaction was carried out in a constant temperature bath for 6 hours.

After completion of the reaction, the sealed tube is opened and the reaction solution is 10 m.
After transferring 1 to a 50 ml flask and adding diglyme (10 ml), tetraethoxysilane (32.76 g, 0.16 mol) and tetrapropoxytitanium (0.67 g, 2.3 mmol) with stirring under air. ,
0.1N hydrochloric acid (5 ml) was added dropwise. 30 minutes later, 0.1
ml reaction solution to PMMA (length 50 mm x width 50 mm x
It was spin-coated on a substrate having a thickness of 2 mm. Next, this substrate was transferred to an oven and heated at 130 ° C. for 1 hour to form a transparent thin film on the PMMA substrate.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The content of the metal species contained in the total weight of the coating was 23% by weight (calculated as the metal oxide contained in the coating). From the solid-state ²⁹ Si-NMR (97.3 MHz; polydimethylsiloxane standard) spectrum of the coating, the four absorption peaks were δ-48.7 ppm, δ-57.2 ppm,
It can be read as δ-66.2 ppm and δ-75.2 ppm,
The absorption peak intensity ratio was 0: 8: 70: 22. The amount of tetrapropoxytitanium used is about 1/100 of the amount of tetraalkoxysilane and can be ignored. Therefore, the degree of crosslinking is ⁹ Si-as in the case of Example 1.
From NMR absorption, 8 × 2/4 + 70 × 3/4 + 22 ×
It was found that 4/4 = 78.5%.

Example 3 Methyl methacrylate (8.56 g, 85.5 mmo)
l), 3-methacryloxypropyltrimethoxysilane (1.12 g, 4.5 mmol), AIBN (15 m
g, 90 μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Next, shake the sealed tube at 70 ° C.
The reaction was carried out in a constant temperature bath for 6 hours.

After the reaction was completed, the sealed tube was opened and the reaction solution was 10 m.
1 was transferred to a 50 ml flask and stirred under air with diglyme (10 ml) and tetraethoxysilane (32.55 g, 0.15 mol), tetrapropoxy titanium (0.67 g, 2.3 mmol) and zirconium acetylacetate. Nart (0.39g, 0.81mmo
l) was added, and 0.1N hydrochloric acid (5 ml) was added dropwise.
After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (50 m in length).
m × width 50 mm × thickness 2 mm) spin-coated on a substrate. Next, this substrate was transferred to an oven and heated at 130 ° C. for 1 hour to form a transparent thin film on the substrate.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The content of metal species contained in the total weight of the coating is 22.
It was 5% by weight (calculated as the metal oxide contained in the coating). Solid-state ² Si-NMR (97.3 MHz;
From the polydimethylsiloxane standard spectrum, the four absorption peaks were δ-48.7 ppm, δ-57.2 pp.
m, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios were 0: 3: 72: 2.
It was 5. The amounts of tetrapropoxytitanium and zirconium acetylacetonate used are about 1/100 of the amount of tetraalkoxysilane and can be ignored. Therefore, the degree of cross-linking can be determined from the absorption of ²⁹ Si-NMR as in the case of Example 1, and can be 3 × 2/4 + 72 × 3/4 +.
It was found that 25 × 4/4 = 80.5%.

Example 4 Methyl methacrylate (8.56 g, 85.5 mmo)
l), 3-acryloxypropyltrimethoxysilane (1.05 g, 4.5 mmol), AIBN (15 m
g, 90 μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Next, shake the sealed tube at 70 ° C.
The reaction was carried out in a constant temperature bath for 6 hours.

After the reaction is completed, the sealed tube is opened and the reaction solution is 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) substrate was spin-coated. Next, the substrate was transferred to an oven and heated at 130 ° C. for 1 hour, whereby a transparent thin film was formed on the substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 150,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The metal species contained in the total weight of the coating was 28% by weight. Solid-state ²⁹ Si-NMR (97.3 MHz;
From the polydimethylsiloxane standard spectrum, the four absorption peaks were δ-48.7 ppm, δ-57.2 pp.
m, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios were 0.01: 9.9.
It was 9:73:17.

From the attribution and absorption intensity of these peaks,
The degree of cross-linking of this film is 0.01 × 1/4 + 9.99 × 2
It was found that /4+73×3/4+17×4/4=75.8%.

Example 5 Methyl acrylate (7.36 g, 85.5 mmol),
3-methacryloxypropyltrimethoxysilane (1.
12 g, 4.5 mmol), AIBN (15 mg, 90
μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Then, the sealed tube was shaken and reacted at 70 ° C. for 6 hours in a constant temperature bath.

After completion of the reaction, the sealed tube was opened and the reaction solution was 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) substrate was spin-coated. Next this PMMA
When the substrate was transferred to an oven and heated at 130 ° C. for 1 hour, a transparent thin film was formed on the PMMA substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 150,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The metal species contained in the total weight of the coating is 28.5% by weight.
Met. Solid state ⁹ Si-NMR (97.3 MH) of the film
z; polydimethylsiloxane standard) from spectrum 4
Book absorption peak is δ-48.7ppm, δ-57.2p
pm, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios are 0: 10: 7.
It was 2:18. From the assignment of these peaks and the absorption intensity, it was found that the degree of crosslinking of this film was 10 × 2/4 + 72 × 3/4 + 18 × 4/4 = 77%.

Example 6 Methacrylic acid (7.36 g, 85.5 mmol), 3-
Methacryloxypropyltrimethoxysilane (1.12
g, 4.5 mmol), AIBN (15 mg, 90 μm)
ol) and diglyme (80 ml) were placed in a sealed tube and degassed. Then, shake the sealed tube at 70 ° C for 6 hours,
The reaction was carried out in a constant temperature bath.

After completion of the reaction, the sealed tube was opened and the reaction solution was 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) substrate was spin-coated. Next this PMMA
When the substrate was transferred to an oven and heated at 130 ° C. for 1 hour, a transparent thin film was formed on the PMMA substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 180,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The metal species contained in the total weight of the coating is 24.8% by weight.
Met. Solid state ²⁹ Si-NMR (97.3 MH) of the coating
z; polydimethylsiloxane standard) from spectrum 4
Book absorption peak is δ-48.7ppm, δ-57.2p
pm, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios are 0: 10: 7.
It was 2:18. From the assignment of these peaks and the absorption intensity, it was found that the degree of crosslinking of this film was 10 × 2/4 + 72 × 3/4 + 18 × 4/4 = 77%.

Example 7 Ethyl methacrylate (9.74 g, 85.5 mmo)
l), 3-acryloxypropyltrimethoxysilane (1.05 g, 4.5 mmol), AIBN (15 m
g, 90 μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Next, shake the sealed tube at 70 ° C.
The reaction was carried out in a constant temperature bath for 6 hours.

After the reaction was completed, the sealed tube was opened and the reaction solution was 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) substrate was spin-coated. Next this PMMA
When the substrate was transferred to an oven and heated at 130 ° C. for 1 hour, a transparent thin film was formed on the PMMA substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 150,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was hardly impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. The metal species contained in the total weight of the coating was 21% by weight. From the solid-state ² Si-NMR (97.3 MHz; polydimethylsiloxane standard) spectrum of the coating, four absorption peaks were δ-48.7 ppm, δ-57.2 ppm,
It can be read as δ-66.2 ppm and δ-75.2 ppm,
The absorption peak intensity ratio is 0: 10: 68: 22.
Met.

From the attribution and absorption intensity of these peaks,
It was found that the degree of crosslinking of this coating was 10 × 2/4 + 68 × 3/4 + 22 × 4/4 = 78%.

Example 8 Acrylic acid (6.15 g, 85.5 mmol), 2-acryloxyethyltributoxysilane (1.467 g,
4.5 mmol), AIBN (15 mg, 90 μmo)
l) and diglyme (80 ml) were placed in a sealed tube and degassed.
Next, the sealed tube was allowed to react in a constant temperature bath at 70 ° C. for 6 hours while shaking.

After completion of the reaction, the sealed tube is opened and the reaction solution is 10 m.
1 was transferred to a 50 ml flask, diglyme (10 ml) and tetraethoxysilane (50.34 g, 0.24 mol) were added with stirring under the atmosphere, and then 0.1
N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2
(mm) substrate was spin-coated. Next this PMMA
When the substrate was transferred to an oven and heated at 130 ° C. for 1 hour, a transparent thin film was formed on the PMMA substrate.

The number average molecular weight of the methacrylic copolymer present in the reaction solution before curing was measured by GPC and found to be 180,000.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was not impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 7H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the crosslinking agent added at the time of preparation was almost entirely consumed in the crosslinking reaction. 30.2% by weight of metal species contained in the total weight of the coating
Met. Solid state ²⁹ Si-NMR (97.3 MH) of the coating
z; polydimethylsiloxane standard) from spectrum 4
Book absorption peak is δ-48.7ppm, δ-57.2p
pm, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios are 0.01: 9.
It was 99:50:40. From the attribution of these peaks and the absorption intensity, the degree of crosslinking of this coating is 0.01 × 1/4 + 9.99 × 2/4 + 50 × 3/4 +
It was found that 40 × 4/4 = 83%.

Comparative Example 1 Methyl methacrylate (8.56 g, 85.5 mmo)
l), 3-methacryloxypropyltrimethoxysilane (1.12 g, 4.5 mmol), AIBN (15 m
g, 90 μmol) and diglyme (80 ml) were placed in a sealed tube and degassed. Next, shake the sealed tube at 70 ° C.
The reaction was carried out in a constant temperature bath for 6 hours.

After completion of the reaction, the sealed tube was opened and the reaction solution was 10 m.
1 g was transferred to a 50 ml flask, diglyme (10 ml) was added thereto with stirring under the atmosphere, and then 0.1 N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2 mm).
Was spin-coated on the substrate. Next, this PMMA substrate was transferred to an oven and heated at 130 ° C. for 1 hour.
A clear thin film formed on the MMA substrate.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was not impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 3H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the metal species contained in the total weight of the coating was 1.2% by weight.

By comparison with the above examples, the copolymer [1] obtained by adding a crosslinking agent such as a metal alkoxide was used.
The effect of improving the hardness of the coating film was remarkable.

Solid state ²⁹ Si-NMR (97.3 M) of the coating
Hz; polydimethylsiloxane standard) spectrum,
The four absorption peaks were δ-48.7 ppm and δ-57.2.
ppm, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios are 15:23:
It was 42:20. From the assignment of these peaks and the absorption intensity, the degree of crosslinking of this coating was 15 × 1/4 + 23 × 2/4 + 42 × 3/4 + 20 × 4.
It was found that / 4 = 67%.

Comparative Example 2 Methacrylic acid (7.36 g, 85.5 mmol), 3-
Methacryloxypropyltrimethoxysilane (1.12
g, 4.5 mmol), AIBN (15 mg, 90 μm)
ol) and diglyme (80 ml) were placed in a sealed tube and degassed. Then, shake the sealed tube at 70 ° C for 6 hours,
The reaction was carried out in a constant temperature bath.

After the reaction was completed, the sealed tube was opened and the reaction solution was 10 m.
1 g was transferred to a 50 ml flask, diglyme (10 ml) was added thereto with stirring under the atmosphere, and then 0.1 N hydrochloric acid (5 ml) was added dropwise. After 30 minutes, 0.1 ml of the reaction solution was added to PMMA (length 50 mm x width 50 mm x thickness 2 mm).
Was spin-coated on the substrate. Next, the spin-coated PMMA substrate was transferred to an oven and heated at 130 ° C. for 1 hour, and a transparent thin film was formed on the PMMA substrate.

The UV-VIS absorption before and after coating is 0.3% at maximum in the wavelength range of 300 to 900 nm.
However, the transparency of the substrate due to the coating was not impaired.

When the fracture surface of the coating film was observed with a scanning electron microscope, it was about 2 μm, and the surface hardness was 3H. When the coating was baked and the ash was subjected to atomic absorption spectrometry, the metal species contained in the total weight of the coating was 0.95% by weight.

By comparison with the above examples, the copolymer [1] obtained by adding a crosslinking agent such as a metal alkoxide to the copolymer [1] was used.
The effect of improving the hardness of the coating film was remarkable.

Solid state ²⁹ Si-NMR (97.3 M) of the coating
Hz; polydimethylsiloxane standard) spectrum,
The four absorption peaks were δ-48.7 ppm and δ-57.2.
ppm, δ-66.2 ppm, δ-75.2 ppm, and the respective absorption peak intensity ratios are 20:21:
It was 35:24. From the attribution of these peaks and the absorption intensity, the degree of cross-linking of this coating was 20 × 1/4 + 21 × 2/4 + 35 × 3/4 + 24 × 4.
It was found that /4=65.8%.

Claims (2)

[Claims] 1. The following general formula: (In the formula, R is hydrogen or an alkyl group having 1 to 5 carbon atoms,
R'represents an alkyl group having 1 to 5 carbon atoms, l is 1 to 3,
Radical copolymer having an alkoxysilyl group represented by m / n in a molar ratio of 99/1 to 80/20) in the side chain (number average molecular weight 50,000 to 300,000: polystyrene conversion) [1] 1 to 60% by weight, The following general formula: (In the formula, R ¹ represents hydrogen, an alkoxy group having 1 to 5 carbon atoms or a phenoxy group, an alkyl group having 1 to 5 carbon atoms or a phenyl group, and R ² represents an alkyl group having 1 to 5 carbon atoms or a phenyl group. , M is Si, Ti, Sn or Zr,
n represents an integer of 1 to 4) and / or a metal alkoxide [2] represented by the following general formula: (M ′ represents Ti, Sn or Zr, R ³ has 1 carbon atom
~ 5 alkyl group, Acac represents acetylacetonate) [3] 99-4
A coating material prepared by dissolving 0% by weight in an organic solvent and adding a Lewis acid thereto. 2. The coating material according to claim 1 is applied onto a substrate and cured by heating to form a metal-oxygen bond having at least one kind of crosslinking site (where the metal is Si or Ti). , Sn or Zr), the metal species of which is 15% by weight or more with respect to the total amount of the coating film, and the degree of crosslinking is 70% or more. A coating method, which comprises forming the (meth) acrylic acid-based transparent cured product film.