JPH10102002A - Composition for photocurable coating agent and formation of coated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for photocurable coating agent capable of providing a high productivity because of a good curability by high energy rays such as ultraviolet rays and electron rays, forming a protecting film having a high hardness, flexibility and excoriation resistance when being cured at a low temperature and improving weather resistance of the protecting film itself and a substrate covered by the film because of its excellent shading effect. SOLUTION: This composition for photocurable coating agent comprises (1) 100 pts.wt. orgnaopolysiloxane having a (meth)acrylic functional group of the formula R<1> m R<2> n Si(OX)p O(4-m-n-p)/2 [R<1> is a 1-10C monofunctional organic group having one or more (meth)acryloxy group; R<2> is a substituted (with the proviso that a (meth)acryl group is omitted) or unsubstituted monofunctional hydrocarbon group; X is H or a 1-4C monofunctional organic group; 0.05<=(m)<=1.00; 0.0<=(n)<=1.55; 0<(p)<=1.80; 0.20<=(m+n)<=1.60; 1.0<=(m+n+p)<=3.9], 1-200 pts.wt. fine powder of an inorganic oxide containing at least one kind of atom selected from titan, cerium and zinc and capable of absorbing light having <=400nm wavelength and (3) 0.01-10 pts.wt. photopolymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various organic materials,
The present invention relates to a photocurable coating composition capable of forming and curing a silicone resin-based coating film on an inorganic material by irradiation of high energy rays such as ultraviolet rays and electron beams, and a method for forming a coating film using the composition.

[0002]

2. Description of the Related Art A coating formed of a silicone resin-based coating material is:
It is a high hardness protective coating with excellent scratch resistance that is difficult to achieve with other organic resin systems.It has good weather resistance and has advantages such as excellent flame retardancy. Applied as a surface protection material. However, this type of conventional silicone resin-based coating material cures by condensation of silanol groups and requires a long time to complete the curing, and thus has the disadvantage of extremely poor productivity. In addition, the coating itself obtained by curing the silicone resin is extremely excellent in weather resistance,
For the purpose of imparting good weather resistance to the treated base material, various types of organic UV are added to the primer layer or the silicone resin layer.
Attempts have been made to incorporate an absorber, but (i) the organic UV absorber thermally decomposes or sublimates or scatters due to heating when forming these coatings;
i) The compound itself decomposes and degrades due to long-term outdoor exposure,
Since the coating has disadvantages such as a decrease in the ultraviolet absorbing ability, excellent weather resistance has not been obtained. Organic UV absorbers are rich in the ability to absorb light mainly in the region around 280 to 320 nm called the UVB region, but have recently been pointed out to have a bad effect on the human body and organic substances from 320 to 400 nm. UV in the range
Since it does not have sufficient ability to block light in the A region, it is insufficient to provide long-term weather resistance. Further, since the silanol group is rich in activity, the coating liquid has a disadvantage that it lacks storage stability.

On the other hand, as a surface treatment method with high productivity, there is a UV curing system using a polyfunctional acrylic compound. The advantage of this system is high productivity based on fast curing. However, since the main skeleton is an organic substance, there is a defect that the weather resistance is insufficient, the hardness as high as that of silicone is difficult, and the properties as a protective coating are insufficient.

As a compromise between the above two, various systems using a silicone resin containing a (meth) acrylic functional group have been proposed (Japanese Patent Publication No. 1-55307, Japanese Patent Publication No. 3-2168, Japanese Patent Publication No. 63-1988). No. 65115).
However, in these systems, short time UV
Since the film is cured only by irradiation and siloxane bonds are not formed in a network, the hardness of the formed film is still insufficient. Even when a silanol group condensation reaction is used in combination for the purpose of increasing the hardness, the hydrolysis of the silane compound is carried out by a hydrolysis method using an acid catalyst in an organic solvent which is usually used frequently. The decomposed product is unstable and lacks storage stability, resulting in poor workability. Further, compared with a UV curing system mainly using a polyfunctional acrylic compound, although the weather resistance is greatly improved, it is still insufficient.

Further, attempts have been made to reduce the transmission of ultraviolet rays by blending inorganic oxide fine particles having ultraviolet blocking properties into the silicone resin layer (Japanese Patent Laid-Open No. 8-2941). However, in this system, although improvement in weather resistance and durability is recognized, productivity is inferior because the curing system applies a condensation reaction of silanol groups.

[0006] As described above, there has been no example in which conventionally known products can achieve both high performance (high hardness, scratch resistance and weather resistance) and high productivity.

The present invention has been made in view of the above circumstances, and has good productivity because of its good curability by irradiation with high energy rays such as ultraviolet rays and electron beams. Photocurable coating agent composition capable of forming an abrasion-resistant protective coating rich in flexibility and having excellent light-shielding effect and capable of improving the weather resistance of the protective coating itself and the coated substrate, and this composition It is an object of the present invention to provide a method for forming a coating film using the same.

[0008]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object and found that (1) the following average composition formula (A): R ¹ _m R ² _n Si (OX) _p O _{(4-mnp) / 2} (A) (wherein, R ¹ is a monovalent organic group having 1 or more carbon atoms and containing at least one (meth) acryloxy group, and R ² is substituted ( However, (excluding (meth) acrylic group) or unsubstituted monovalent hydrocarbon group, X represents a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms, and m, n, and p are 0.05 ≦ m. ≦ 1.00, 0 ≦ n ≦ 1.55, 0 <p ≦ 1.80, 0.20 ≦ m + n ≦ 1.60, 1.0 ≦ m + n + p ≦ 3.0.) (2) containing at least one atom selected from titanium, cerium, and zinc; A coating agent composition containing 1 to 200 parts by weight of an inorganic oxide fine particle absorbing a light beam having a wavelength of 400 nm or less, and (3) 0.01 to 10 parts by weight of a photopolymerization initiator is photopolymerizable. Irradiation with a high energy ray of an amount or more, even when a large amount of the inorganic oxide fine particles (inorganic ultraviolet absorber) is blended, effectively promotes (meth) acrylic polymerization and achieves good curing. Imparts the property and progresses in a short time, and the inorganic ultraviolet absorber absorbs light rays in a low energy amount irradiation area in a wide wavelength range such as outdoor exposure, but is not easily deteriorated by itself. It has been found that it has good weather resistance over a long period of time. In this case, when an organic compound (organic ultraviolet absorber) having the ability to absorb light having a wavelength of 400 nm or less is used in combination, light in a wide UV region can be efficiently emitted by the synergistic action of both inorganic and organic compounds. It can be well absorbed, and furthermore, by blending a silanol condensation catalyst and heating and condensing the remaining silanol groups after photocuring, it is possible to obtain a cured film having higher hardness and excellent scratch resistance. The present invention has led to the present invention.

Accordingly, the present invention firstly provides (1) 100 parts by weight of the above (meth) acrylic functional group-containing organopolysiloxane, (2) 1 to 200 parts by weight of the above inorganic oxide fine particles, and (3) photopolymerization. A photocurable coating agent composition containing 0.01 to 10 parts by weight of an initiator, and in addition to the above components (1) to (3), (4) a silanol condensation catalyst, 0.01 to 10 parts by weight, and And / or (5) To provide a photocurable coating composition containing 1 to 50 parts by weight of an organic ultraviolet absorber.
Further, the present invention, after coating the composition on the substrate surface,
This coating is irradiated with high energy rays to polymerize the (meth) acrylic group in the composition, and a method of forming a coating film that cures the coating, and in this case, if necessary, the coating is applied to the coating. A method is provided in which after curing by irradiation with a high energy beam, the cured product is heated to condense the remaining OX groups in the composition and to perform secondary curing.

Hereinafter, the present invention will be described in more detail.

The first component of the photocurable coating composition according to the present invention is a (meth) acryl functional group-containing organopolysiloxane (silicone resin) represented by the following average composition formula (A). ^{_{R 1 m R 2 n Si (}} OX) p O (4-mnp) / 2 (A)

Here, R ¹ is a substituent which is polymerized and cross-linked by a high energy ray, and has a (meth) acryloxy group of 1
Represents a monovalent organic group having 1 to 10 carbon atoms. In this case, examples of the (meth) acryloxy group include those substituted with one or more hydrogen atoms bonded to a carbon atom, such as an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkoxyalkyl group. In particular,
(Meth) acryloxymethyl group, 3- (meth) acryloxypropyl group, 2-methyl-3- (meth) acryloxypropyl group, 6- (meth) acryloxyhexyl group,
10- (meth) acryloxydecyl group, p- (meth) acryloxyphenyl group, 2- [p- (meth) acryloxymethylphenyl] ethyl group, 3- [2,3-di (meth) acryloxypropoxy ] Propyl group and the like. One or more of these may be used. From the economic viewpoint and the properties of the cured product, a 3- (meth) acryloxypropyl group is particularly preferred.

R ² represents a substituted (unless a (meth) acrylic functional group) having 1 to 10 carbon atoms or an unsubstituted monovalent hydrocarbon group, and is water-repellent, flexible and adhesive to the organopolysiloxane. And the like. In this case, the unsubstituted monovalent hydrocarbon group includes a methyl group,
Examples include an alkyl group such as an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group and a decyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, an alkenyl group such as a vinyl group, and an aralkyl group. .
As the substituted monovalent hydrocarbon group, part or all of the hydrogen atoms bonded to the carbon atoms of the unsubstituted monovalent hydrocarbon group may be (i) a halogen atom such as fluorine or chlorine, or (ii)
Epoxy functional groups such as glycidyloxy group and epoxycyclohexyl group; (iii) amino groups such as amino group, aminoethylamino group, phenylamino group and dibutylamino group; and (iv) sulfur-containing functional groups such as mercapto group and tetrasulfide group. , (V) an alkyl ether group such as a (polyoxyalkylene) alkyl ether group, (vi) an anionic group such as a carboxyl group or a sulfonyl group,
(Vii) a quaternary ammonium salt structure-containing group,
Those substituted with a conventionally known substituent excluding a (meth) acrylic functional group are exemplified.

Specific examples of R ² include trifluoropropyl, perfluorobutylethyl, perfluorooctylethyl, 3-chloropropyl, 2- (chloromethylphenyl) ethyl, and 3-glycidyloxypropyl. Group, 2- (3,4-epoxycyclohexyl) ethyl group, 5,6-epoxyhexyl group, 9,10-epoxydecyl group, 3-aminopropyl group, N- (2-aminoethyl) aminopropyl group, 3 -(N-phenylamino)
Propyl group, 3-dibutylaminopropyl group, 3-mercaptopropyl group, 2- (4-mercaptomethylphenyl) ethyl group, polyoxyethyleneoxypropyl group,
Examples thereof include a 3-hydroxycarbonylpropyl group and a 3-tributylammoniumpropyl group.
It is not limited to these specific examples, and any one can be used as long as it satisfies the above conditions.
One type or two or more types may be used. In particular, when a high hardness coating is required, a methyl group is preferable, and when another organic resin is used in combination, a phenyl group is preferably used because compatibility is improved, and when adhesion to a substrate is emphasized, Preferably employs an epoxy functional group.

The OX group represents a condensable silanol group or a hydrolyzable group of the present silicone resin. Therefore, X
The group represents a hydrogen atom or a monovalent organic group having 1 to 4 carbon atoms, such as an alkyl group, an alkenyl group,
Specific examples include an alkoxyalkyl group, an acyl group, and an alkenyloxy group, and specific examples include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropenoxy group, and an acetoxy group.

M, n, and p represent the contents of the above substituents, respectively, 0.05 ≦ m ≦ 1.00, 0 ≦ n ≦
1.55, 0 <p ≦ 1.80, 0.20 ≦ m + n ≦ 1.
Represents a number satisfying the range of 60. More preferably 0.0
7 ≦ m ≦ 1.00, 0 ≦ n ≦ 1.00, 0.05 ≦ p ≦
1.60, 0.40 ≦ m + n ≦ 1.50. Also,
m + n + p is 1.0 ≦ m + n + p ≦ 3.0, and particularly preferably 1.2 ≦ m + n + p ≦ 2.5.

M, which means the content of the acrylic functional substituent, is related to the density at which polymerization and cross-linking is caused by high-energy radiation. If it is smaller than 0.05, the hardness becomes insufficient or the primary curing becomes tack-free. It is not preferable because it is unlikely to cause a decrease in productivity. If it is larger than 1.00, the hardness becomes too high and the coating film has insufficient flexibility, so that cracks are easily generated, which is not preferable. N, which means the content of an organic substituent other than the (meth) acrylic functional group, may be 0, and if it is more than 1.55, the hardness of the cured film becomes too low, which is not preferable. (M + n) is 0.20
If it is less, the residual amount of the organic group is too small, and the cured film becomes too hard, so that the abrasion resistance is insufficient.
If it exceeds 1.60, the hardness of the cured film becomes too low, which is not preferable. P, which means the content of the silanol group or the hydrolyzable group, may be 1.80 or less in order to form a dense film which is rich in condensation curability and is 1.80.
If it is larger, the organopolysiloxane resin solution becomes unstable, which is not preferable. In particular, p preferably satisfies the range of 1.60 or less.

As the organopolysiloxane having a (meth) acrylic functional group of the present invention, any one can be applied as long as it satisfies the above conditions.

Such an organopolysiloxane (silicone resin) can be produced by the following formulation.

First, as a silane compound as a starting material, various hydrolyzable silane compounds having the following structure and containing R ¹ and / or R ² as an organic substituent, and partially hydrolyzed / condensed products thereof are used. Can be used.

Si (OX)_Four, R¹ Si (OX)_Three, R^Two S
i (OX)_Three, R¹ _TwoSi (OX )_Two, R^Two _TwoSi (O
X)_Two, R¹ R^TwoSi (OX)_Two, R¹ _TwoR^TwoSi (OX),
R¹ R^Two _TwoSi (OX), R^Two _ThreeSi (OX)

The T units having three hydrolyzable groups form a three-dimensional siloxane bond (polysiloxane network having a high degree of crosslinking) by a condensation reaction, and serve as a basis for forming a hard and scratch-resistant film. Component, 30 to 10
It is preferably contained at 0 mol%. If the amount is less than 30 mol%, the crosslinking density is insufficient and a high-hardness film is not formed, which is not preferable. More preferably, it contains 40 mol% or more of T units. As constituent units other than the T unit,
It is possible to contain a D unit containing two organic substituents or a Q unit containing no organic substituent at all. The content of these components is optional, but if it is desired to impart flexibility and flexibility to the coating, the content of the D unit may be increased, and conversely, if the hardness is high, the content of the Q unit may be increased. Just increase the rate. These units may be mixed and used at an arbitrary ratio in order to obtain desired physical properties. It is more preferable to use methoxysilane or ethoxysilane from the viewpoint of operability and easy removal of by-products.

The method for producing the organopolysiloxane applied in the present invention using the above-mentioned raw materials will be described. In principle, it is sufficient to hydrolyze the above-mentioned various hydrolyzable silane compounds. It is possible to apply the above method. That is, (a) a method of hydrolysis in an organic solvent, (b) a method of hydrolysis in water, and (c) a method of hydrolysis without a solvent can be exemplified. When aiming at a double curing system of polymerization with high energy rays and condensation of silanol groups, it is necessary to prepare a resin rich in this inherently unstable silanol group.
Alternatively, the method (b) is preferably adopted. The method (a) or (c) is a method suitable for obtaining a resin having excellent storage stability in which a hydrolyzable group other than a silanol group is positively left.

In carrying out the hydrolysis reaction, a hydrolysis catalyst may be used. It is advisable to add the catalyst directly to the hydrolysis system, or to disperse and dissolve the hydrolysis catalyst in water to be used. As the hydrolysis catalyst, conventionally known catalysts can be used. (A) mineral acids such as acetic acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and hydrogen fluoride; (b) oxalic acid;
Carboxylic acids such as maleic acid, (c) sulfonic acids such as methanesulfonic acid, (d) acidic or weakly acidic inorganic salts such as KF, (e) ion exchange resins having a sulfonic acid group or a carboxylic acid group on the surface, etc. (F) basic substances such as lithium hydroxide, sodium hydroxide, potassium hydroxide and sodium methylate; (g) organic acid salts such as sodium acetate and sodium formate; (h) ammonia, butylamine; amine compounds such as n-hexylamine, triethylamine, diazabicycloundecene, (i) tetraisopropyl titanate, tetrabutyl titanate, aluminum triisobutoxide, aluminum triisopropoxide, aluminum acetylacetonate, aluminum perchlorate, chloride Aluminum, cobalt octi Over DOO, cobalt acetylacetonate, zinc octylate, zinc acetylacetonate,
Iron acetylacetonate, tin acetylacetonate,
It is possible to use metal-containing compounds such as dibutyltin octylate and dibutyltin laurate.
These catalysts may be used in combination of two or more. The amount of the hydrolysis catalyst is preferably in the range of 0.001 to 10 mol% based on 1 mol of the hydrolyzable group on the silicon atom.

If necessary, after completion of the hydrolysis, it may be neutralized or may be removed by filtration. Finally, the system p
H is a pH at which silanol groups are likely to be stably present = 2 to 7,
It is particularly preferable to control the pH to 3 to 6 from the viewpoint of securing stability. A combination of an acid and a basic compound serving as a buffer for adjusting the pH, such as acetic acid and sodium acetate, disodium hydrogen phosphate and citric acid, may be added.

Organic solvents usable in the method (a) include methanol, ethanol, isopropanol, n-butanol, isobutanol, t-butanol, t-amyl alcohol, butyl cellosolve, 3-methyl-3-methoxybutanol, Alcohols such as acetone alcohol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and acetylacetone, ethers such as propylene glycol monomethyl ether, dipropylene glycol monomethyl ether and diisopropyl ether, esters such as ethyl acetate and isobutyl acetate, and toluene , Aromatics such as xylene, amides such as dimethylformamide, and solvents such as dimethylsulfoxide, but are not limited thereto.

Next, the amount of water used for hydrolysis is
Good to meet the range of 0.1 to 50 in molar ratio _{(H 2 O / Si-OX} ). If the molar ratio is less than 0.1, the degree of polymerization is low, the volatility is high, and as a result, the coating property is poor, which is not preferable. On the other hand, if the molar ratio exceeds 50, the pot yield decreases, the productivity becomes poor, and it is not economically preferable. Further, from the viewpoint of securing an appropriate molecular weight, the molar ratio preferably satisfies the range of 0.2 to 30. In particular, when hydrolysis is carried out in a system or an aqueous solution having a large excess of water, a resin containing a large amount of T-2 units represented by R-Si (O-Si≡) _2- OH in T units is prepared. Can be. The silanol group of the T-2 unit is stable during storage, but has a characteristic of exhibiting remarkable activity when cured by heating, and has a linear property to impart flexibility to the cured film. Therefore, the resin is more preferable.

In carrying out this hydrolysis, the system may be heated for the purpose of accelerating or completing the reaction.

When the hydrolysis is carried out, it may be carried out using inorganic oxide fine particles capable of absorbing light having a wavelength of 400 nm or less or a system in which metal oxides described later are dispersed.

Next, inorganic oxide fine particles (inorganic UV absorber) having the ability to absorb harmful light rays having a wavelength of 400 nm or less which decompose and degrade the organic compound as the second component of the present invention will be described. And titanium, cerium,
Since zinc oxide has the ability to absorb light having a wavelength of 400 nm or less, it is necessary that the inorganic oxide fine particles of the present invention contain at least one of these atoms. To the inorganic oxide fine particles, for the purpose of stabilizing the particles or improving the weather resistance, a metal oxide other than the above is simply added as long as the light absorption function is not hindered. Mechanically adsorb around the inorganic oxide fine particles, coat a thin layer of metal oxide on the surface of the inorganic oxide fine particles, or dope the inorganic oxide fine particles to form a mixed crystal. You may. Specific examples of the metal include Si (silica), Al (alumina), and S (silica).
Examples thereof include, but are not limited to, n (tin oxide), Zr (zirconium oxide), Sb (antimony oxide), Fe (iron oxide), and rare earth metals (rare earth oxides). Among these, in particular, Si, A
1, Sn, Zr and the like are preferable.

The particle diameter of the present inorganic oxide fine particles is from 1 to 30.
0 μm, more preferably 1 μm.
It is preferably in the range of ~ 200mμ. If it exceeds 300 μm, the light transmittance may be deteriorated. Those having a particle diameter of less than 1 mμ are not suitable because they are too unstable and difficult to produce. The present inorganic oxide fine particles can be used in the form of a powder, an aqueous dispersion, an organic solvent dispersion, or the like. As the usable solvent, all of the above-mentioned organic solvents can be used.

The amount of the inorganic oxide fine particles is preferably 1 to 200 parts by weight based on 100 parts by weight of the (meth) acryl functional group-containing organopolysiloxane of the present invention. Addition of less than 1 part by weight is not preferable because light shielding ability is insufficient and only insufficient weather resistance can be obtained. On the other hand, if the amount exceeds 200 parts by weight, the binder component in the cured film becomes insufficient, so that the film strength becomes weak and non-transparent, which is not preferable. More preferably, 2 to 10
It is preferable to contain 0 parts by weight.

Next, the photopolymerization initiator of the third component used in the present invention will be described. As the photopolymerization initiator, a radical is generated by absorbing a high energy ray represented by ultraviolet rays, an electron beam, radiation, and the like, and an unsaturated double bond such as a (meth) acryl group contained in the present invention is removed. There is no particular limitation as long as it has the ability to polymerize. Specifically, benzoin derivatives such as benzoin, benzoin ethyl ether, benzoin propyl ether and benzoin isopropyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2 2-hydroxy-2-methyl- such as -hydroxy-2-methylpropan-1-one
1-phenylpropan-1-one derivatives, acetophenone derivatives such as dimethoxyacetophenone and diethoxyacetophenone; benzophenone derivatives having no 2-hydroxy group such as benzophenone, 4,4'-bis (dimethylamino) benzophenone and 4-trimethylsilylbenzophenone , 1-hydroxycyclohexylphenyl ketone, methylphenylglyoxylate, benzyldimethylketal, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like.

These photopolymerization initiators are the (meth) acryl functional group-containing organopolysiloxanes 10 of the present invention.
It is preferable to use 0.01 to 10 parts by weight with respect to 0 parts by weight. If the addition is less than 0.01 part by weight, the curing speed becomes slow and good productivity cannot be obtained, which is not preferable. Also, 1
Exceeding 0 parts by weight is not preferred because this component does not participate in crosslinking and softens the cured film. More preferably, the amount satisfies the range of 0.1 to 5 parts by weight.

The photocurable coating composition of the present invention preferably contains a silanol condensation catalyst. As the silanol condensation catalyst, conventionally known catalysts can be used. For example, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, sodium formate, n-hexylamine, tributylamine, diazabicycloun Basic compounds such as decene;
Tetraisopropyl titanate, tetrabutyl titanate, aluminum triisobutoxide, aluminum triisopropoxide, aluminum acetylacetonate, aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, zinc octylate, zinc acetylacetonate, iron Metal-containing compounds such as acetylacetonate, tin acetylacetonate, dibutyltin octylate and dibutyltin laurate; and acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid.

The amount of the present silanol condensation catalyst is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the (meth) acryl functional group-containing organopolysiloxane of the present invention. Addition of less than 0.01 part by weight may cause the silanol group condensation to stop at a sufficient rate,
Further, when the amount exceeds 10 parts by weight, the strength of the coating film becomes weak, which is not preferable.

The photocurable coating composition of the present invention contains the above-mentioned first to third components as essential components, and further has an organic compound (organic compound) having the ability to absorb light having a wavelength of 400 nm or less. UV absorber). In this case, as the organic UV absorber,
An organic compound having any structure can be applied as long as it has an ability to absorb a light beam having a wavelength of 400 nm or less. Particularly, a compound derivative whose main skeleton is a 2-hydroxybenzophenone-based, benzotriazole-based, cyanoacrylate-based, or triazine-based is preferable. 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy- 5-t-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, ethyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexyl-2- Cyano-3,3
Polymer of diphenyl acrylate, 4- (2-acryloxyethoxy) -2-hydroxybenzophenone, 2
-(2-hydroxy-4-hexyloxyphenyl)-
Examples thereof include 4,6-diphenyltriazine and the like, but are not limited to these examples.

The present organic UV absorber works in synergy with the inorganic UV absorber to improve weather resistance and durability. The amount of the present organic UV absorber is from 1 to 5 based on 100 parts by weight of the (meth) acryl functional group-containing organopolysiloxane of the present invention.
It is recommended to use 0 parts by weight. With less than 1 part by weight,
If the effect is not sufficiently exhibited, and if it exceeds 50 parts by weight, the binder component in the cured film is insufficient, so that the film strength is low and the film is not transparent, which is not preferable. More preferably, the content is 2 to 30 parts by weight.

The composition of the present invention further comprises, in addition to the above components,
A non-silicone polyfunctional (meth) acrylic compound that functions as a cross-linking agent and plays a role in improving adhesion when irradiated with high-energy radiation within a range where the properties of the coating are not deteriorated. Functional silica, alumina, tin oxide, inorganic oxide fine particles such as zirconium oxide, hindered amine-based light stabilizers, organic resins, pigments, dyes for the purpose of imparting excellent film performance,
A leveling agent and a storage stabilizer may be added for the purpose of obtaining good solution stability.

As the non-silicone polyfunctional (meth) acrylic compound, any compound can be used as long as it contains two or more (meth) acrylic functional groups in one molecule. ) Acrylate,
1,3-butanediol di (meth) acrylate, 1,
6-hexanediol di (meth) acrylate, 1,9
-Nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, Polypropylene glycol di (meth) acrylate, 2-hydroxy-1,3-di (meth) acryloxypropane, 2,2-bis [4-((meth) acryloxyethoxy) phenyl] propane, 2,
Bifunctional (meth) acrylates such as 2-bis [4-((meth) acryloxypolyethoxy) phenyl] propane, trimethylolpropane tri (meth) acrylate, tris (hydroxymethyloxyethyl) propane tri (meth) acrylate, Examples include trifunctional (meth) acrylates such as pentaerythritol tri (meth) acrylate and tris [(meth) acryloxyethyl] isocyanurate, and tetrafunctional (meth) acrylates such as pentaerythritol tetra (meth) acrylate. Can be. In addition, divinylbenzene or the like that is polymerized by irradiation with high energy rays and acts as a crosslinking agent is also applicable. This component is the (meth) of the present invention.
It is preferable to use 0 to 500 parts by weight based on 100 parts by weight of the organopolysiloxane having an acrylic functional group. It is not particularly necessary to use them together, but it is better to use them slightly in order to improve the adhesiveness. If it is added in excess of 500 parts by weight, the characteristics of the silicone system disappear, and advantages such as weather resistance and high hardness cannot be obtained. Particularly preferably, 0 to 200 parts by weight is used.

In order to further improve the stability of the silanol group, a combination of an acid and a basic compound serving as a buffer for adjusting the pH, such as acetic acid and sodium acetate, disodium hydrogen phosphate and citric acid, etc. May be added to adjust the inside of the system to pH = 3-6.

Next, a method for forming a cured film using the coating composition of the present invention will be described. The method of treating the surface of various substrates comprises the following steps. That is, the composition is coated with a coating solution prepared by adding various diluents, various additives, and a curing catalyst, if necessary, to the substrate, and further, if necessary, air-drying or short-time drying. The first step of coating and forming a coating film by removing volatile components such as solvents from the coating film by heating and drying, irradiating high energy rays such as ultraviolet rays and electron beams to make the coating tack-free The second to cure until
, More preferably the tack-free coating is further heated, and the third step of condensing and curing silanol groups to increase the hardness of the coating is sequentially performed. In this case, as a coating method, a usual method such as flow coating, dip coating, spray coating, spin coating, and roll coating can be applied, and the coating is usually applied to the substrate surface to a thickness of 0.1 to 10 μm. Is preferred.
If the thickness is less than 0.1 μm, the surface protection performance may be insufficient, which may be inappropriate. If the thickness is more than 10 μm, cracks may easily occur. The irradiation amount of high energy rays such as ultraviolet rays or electron beams is 20 to 2
It is preferable that the irradiation time is 00 W / cm ² and the irradiation time is 5 to 600 seconds. After the high energy beam irradiation, the heat curing step of condensing the remaining silanol groups by heating is performed in 30
The treatment is preferably performed at a temperature in the range of from 250 to 250 ° C. for 5 to 120 minutes, and in particular, from the viewpoint of shortening the curing time and preventing the deterioration of the base material.

The coating composition of the present invention is applicable to any organic or inorganic material such as a plastic molded article, wood-based product, ceramics, glass, metal, or a composite thereof as a base material. It is not something to be done.

[0044]

According to the present invention, the composition comprising the organopolysiloxane containing a certain amount of the (meth) acrylic functional group and the inorganic oxide fine particles having an absorption property in the UV region is characterized as follows. (1) High energy rays (UV, E
Irradiation with B) surprisingly progresses (meth) acrylic polymerization and cures in a short time, even if it contains a large amount of UV absorber. Therefore, the productivity is extremely good. (2) Light is absorbed in a low energy amount irradiation region in a wide wavelength region such as outdoor exposure, but the light-absorbing inorganic oxide fine particles themselves are hardly deteriorated by light, so that the cured film has excellent long-term weather resistance and durability. Properties can be imparted. (3) When an organic UV absorber is used in combination, light in a wide range of UV region can be efficiently absorbed by a synergistic effect. (4) After the photocuring, if the remaining silanol groups are further condensed by heating, the acrylic polymer portion and the siloxane portion form an interpenetrating network structure, so that the cured film has extremely high hardness and scratch resistance. Excellent coating. (5) Since the acrylic polymer part contributes to the improvement of adhesion, the cured epoxy resin containing (meth) acrylic functional group has better adhesiveness to the substrate than the silicone resin having no acrylic functional group. Is good.

Therefore, the conventional method cannot achieve both high productivity and high functionality such as high hardness and high weather resistance, but this method can achieve both.

[0046]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to adjustment examples, examples and comparative examples, but the present invention is not limited to the following examples.

[Preparation Example 1] 900 L of water was placed in a 2 L flask.
g (50 mol), and 468.7 g (2.0 mol) of 3-acryloxypropyltrimethoxysilane was added at room temperature.
l) Added and mixed. Under ice-cooling, 180 g (10 mol) of a 0.05N aqueous hydrochloric acid solution was added dropwise over 30 minutes, followed by complete hydrolysis in water (Method I). After dropping, add 2
Stir for hours to complete the hydrolysis. Thereafter, methanol and water generated by the hydrolysis were distilled off under reduced pressure at 70 ° C.
The solution was concentrated to the initial 85% to obtain an almost alcohol-free aqueous solution. When this solution was allowed to stand overnight, the viscous organopolysiloxane resin settled and separated into two layers. 600 g of MIBK was added thereto, and the lower aqueous layer was separated and removed to obtain 871 g of a colorless and transparent organopolysiloxane resin solution (A) having a solid content of 37.6% by weight.
The number average molecular weight of the obtained organopolysiloxane was 1.
It was 5 × 10 ³ (GPC).

The organopolysiloxane resin solution was converted to NaC
When the IR spectrum of the thin film after dropping it on a 1-plate and evaporating the solvent was measured, the following characteristic absorption was observed, but no absorption near 2850 cm ^-1 attributed to a methoxy group was observed. . Therefore, it is determined that no methoxy group remains in this resin. (1) 1055, 1124 cm ^-1 {Si-O-Si} (2) 1724 cm ^-1 C = CC (= O) -O- (3) 3432 cm ^-1 @ Si-OH This organopolysiloxane resin solution ²⁹ Si-NMR
As a result, three broad signals assigned to Table 1 were observed.

[0049]

[Table 1]

From the results of this measurement, it was found that this resin solution contained no monomeric T-0 units, but contained 36 mol% of T-2 units in all T units, and 42 mol% of OH groups.
(Vs. Si).

From the above, the obtained organopolysiloxane resin can be represented by the following average composition formula.

[0052]

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[Preparation Example 2] 187.5 g of 3-acryloxypropyltrimethoxysilane was placed in a 2 L flask.
(0.8 mol), 43.7 g (0.2 mol) of 3-acryloxypropylmethyldimethoxysilane, 152.2 g (1.0 mol) of tetramethoxysilane, and 100 g of methyl alcohol were added and mixed. Under ice-cooling, 126.1 g of a 0.05N aqueous hydrochloric acid solution (7.0 mol)
l) was added dropwise over 30 minutes, and hydrolysis was carried out in an organic solvent (Method II). After completion of the dropwise addition, the mixture was heated at 40 ° C. for 2 hours and
After stirring for an hour, the hydrolysis was completed, and 545 g of a colorless and transparent organopolysiloxane resin solution (B) was obtained. The number average molecular weight of the obtained organopolysiloxane is 1.6 × 1
0 ³ (GPC).

When the abundance ratio of each structural unit was measured by ²⁹ Si-NMR analysis in the same manner as in Preparation Example 1, the total (silanol group + methoxy group) was 1.14 mol (based on S).
(1 mole of i atom). In addition, ¹ H-NMR
Analysis was carried out, and it was found from the integral ratio of the methoxy group and the methyl group that the methoxy group was present at 0.43 mol (relative to 1 mol of Si atom). From the above results, the obtained organopolysiloxane resin can be represented by the following average composition formula.

[0055]

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[Preparation Example 3] Instead of 3-acryloxypropylmethyldimethoxysilane in Preparation Example 2,
41. glycidoxypropylmethyldimethoxysilane
2 g (0.2 mol) is used, and 0.1 g for hydrolysis is used.
The amount of the 05N hydrochloric acid aqueous solution was reduced to 34.2 g (1.9 mol), and partial hydrolysis was carried out in the same manner as in Preparation Example 2 (III).
Law). After completion of the hydrolysis, low-boiling substances are distilled off under reduced pressure, and MIB
The mixture was diluted with K to obtain 493 g of a colorless and transparent organopolysiloxane resin solution (C) containing 50% of the active ingredient. The number average molecular weight of the obtained organopolysiloxane is 1.4 × 10 ^3.
(GPC).

By the same analysis as in Preparation Example 2, it was found that the obtained organopolysiloxane resin could be represented by the following average composition formula.

[0058]

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[Preparation Example 4] Hydrolysis with the composition of Preparation Example 2 was carried out in the presence of titanium oxide sol (Method IV).
The titanium oxide sol contains 85% TiO _{2 and} has a surface of S
400 n coated with iO ₂ and having an average particle size of 20 μm
These are composite oxide fine particles having the ability to absorb light having a wavelength of not more than m, and used as a methanol dispersion solution (G) containing 20% of the present fine particles as a solid content. This titanium oxide sol is treated with an organopolysiloxane resin solid content of 100.
20 parts by weight in terms of solid content was added to the parts by weight, and hydrolysis was carried out in the same manner as in Preparation Example 2 to obtain an organopolysiloxane resin solution (D).

[Preparation Example 5] Instead of 3-acryloxypropylmethyldimethoxysilane in Preparation Example 2, 36.4 g (0.2 mol) of phenylmethyldimethoxysilane was used.
l) The same procedure as in Preparation Example 2 was carried out except that 3 g of water and 126 g (7.0 mol) of water were used instead of a 0.05 N aqueous hydrochloric acid solution for hydrolysis, using a cation exchange type ion exchange resin as a hydrolysis catalyst. Hydrolysis in an organic solvent to
495 g of a colorless and transparent organopolysiloxane resin solution (E) containing 50% of the active ingredient was obtained. The number average molecular weight of the obtained organopolysiloxane was 1.4 × 10 ³ (GPC).

By the same analysis as in Preparation Example 2, it was found that the obtained organopolysiloxane resin could be represented by the following average composition formula.

[0062]

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[Comparative Preparation Example 1] In Preparation Example 1, 468.7 g of 3-acryloxypropyltrimethoxysilane was used.
9.4 g (0.04 mol) of 3-acryloxypropyltrimethoxysilane instead of (2.0 mol),
And 266.6 g (1.9) of methyltrimethoxysilane.
6 mol) and hydrolyzed similarly. The number average molecular weight of the obtained organopolysiloxane is 1.2 × 1.
0 ³ (GPC).

From the result of the same analysis, the obtained organopolysiloxane resin solution (F) had the following average composition formula.

[0065]

Embedded image Table 2 summarizes the results of the above Preparation Examples and Comparative Preparation Examples.

[0066]

[Table 2]

Example 1 The solid content of the organopolysiloxane resin solution (A) obtained by the above-mentioned preparation method was 100%.
300 parts by weight of a methanol dispersion of titanium oxide sol (G) (60 parts by weight in terms of solid content),
-Hydroxy-2-methyl-1-phenylpropane-1
One part by weight of -one and 0.6 parts by weight of aluminum acetylacetonate were added to prepare a coating solution. The obtained coating solution was applied to a polished steel plate having a clean surface using a bar coater (No. 20), and air-dried at room temperature for 10 minutes.

Next, from a distance of 8 cm from the steel plate,
Ultraviolet rays were irradiated for 30 seconds with a high-pressure mercury lamp of 80 W / cm ² . The obtained coating film was checked for the presence or absence of tack, measured for the pencil hardness of the cured film according to JIS K-5400, and further evaluated for the pencil hardness of the film cured by heating at 80 ° C. for 30 minutes. In addition, using a sunshine long life weather meter, 30
The light resistance after irradiation for 00 hours was confirmed.

Regarding the light fastness, a film having no property and coloration of the film was evaluated as ○, a film having poor adhesion and light yellowing was evaluated as Δ, and a film having peeled or yellowed was evaluated as ×. Table 3 shows the results.

Examples 2 to 10 and Comparative Examples 1 to 3 In the same manner as in Example 1, the types and amounts of the organopolysiloxane resin and the metal oxide fine particles were changed, and an organic UV absorber was further added. Thus, the compositions shown in Table 3 were prepared and evaluated in the same manner as described above. Table 3 summarizes the results.

As the metal oxide fine particles, titanium oxide (H) having an average particle diameter of 20 μm,
mμ, and the composition ratio is TiO ₂ / ZrO ₂ / SiO ₂ = 70
/ 8/22 mixed crystal type composite titanium oxide (I), cerium oxide (J) having an average particle diameter of 20 mμ, and zinc oxide (K) surface-treated with silica having an average particle diameter of 20 mμ and 15% by weight It was used.

[0072]

[Table 3]

From the results in Table 3, it can be seen that when an organopolysiloxane resin having a small acrylic functional group is used as the base resin, tack-free is not achieved only by ultraviolet irradiation, and the second component absorbs light having a wavelength of 400 nm or less. It has been found that a composition having a low content of the inorganic oxide fine particles having the ability to perform light resistance has insufficient light resistance.

Example 11 The solid content of the organopolysiloxane resin solution (A) obtained by the above preparation method was 10%.
300 parts by weight of a methanol-dispersed solution (G) of titanium oxide sol (60 parts by weight in terms of solid content) with respect to 0 parts by weight;
2-hydroxy-2-methyl-1-phenylpropane-
1-one part by weight, 0.6 part by weight of aluminum acetylacetonate, and 60 parts by weight of trimethylolpropane triacrylate were added to prepare a coating solution. The obtained coating solution was applied to a polycarbonate plate having a clean surface using a bar coater (No. 20), and air-dried at room temperature for 10 minutes.

Next, ultraviolet rays were irradiated from a distance of 8 cm from the polycarbonate plate with a high-pressure mercury lamp of 80 W / cm ² for 30 seconds, followed by heating and curing at 80 ° C. for 30 minutes. About the obtained coating film, the scratch resistance was determined by the degree of scratching after the steel wool of # 0000 was reciprocated 50 times on the coating film, and after the cut film was cut into 10 × 10 crosscuts, A cellophane tape peeling test was performed, and the adhesion was determined by counting the remaining squares. Further, the light resistance after irradiation for 3000 hours was confirmed using a sunshine long life weatherer meter.

The criteria for abrasion resistance were as follows: い な い when no scratch was found, △ when several scratches were found, and x when scratch was as much as the substrate. Light fastness was determined in the same manner as above. Table 4 shows the above results.

Examples 12 to 20, Comparative Examples 4 to 6 Regarding organopolysiloxane resin and metal oxide fine particles,
Change the type and amount, further add an organic UV absorber,
The compositions in Table 4 were prepared in the same manner as in Example 11, and evaluated in the same manner as described above. The results are summarized in Table 4.

[0078]

[Table 4]

From the results shown in Table 4, it can be seen that when an organopolysiloxane resin having a small acrylic functional group is used as the base resin, tack-free is not obtained only by irradiation with ultraviolet light, and the second component absorbs light having a wavelength of 400 nm or less. It has been found that light resistance is insufficient when the content of the inorganic oxide fine particles having a low content is low, and that the light resistance may be further improved when an organic UV absorber is used in combination.

Claims (6)

[Claims] (1) The following average composition formula (A): R ¹ _m R ² _n Si (OX) _p O _{(4-mnp) / 2} (A) (wherein R ¹ represents a (meth) acryloxy group At least one monovalent organic group having 1 to 10 carbon atoms, R ² is a substituted (excluding (meth) acrylic group) or unsubstituted monovalent hydrocarbon group, and X is a hydrogen atom or a monovalent hydrocarbon group. Represents a monovalent organic group of 4 to 4. m, n, and p are 0.05 ≦ m ≦ 1.00, 0 ≦ n ≦ 1.55, 0 <p ≦ 1.80, 0.20 ≦ m + n ≦ 1 .60, 1.0 ≦ m + n + p ≦ 3.0) 100 parts by weight of a (meth) acrylic functional group-containing organopolysiloxane represented by the following formula: (2) at least one selected from titanium, cerium and zinc 1 to 200 parts by weight of inorganic oxide fine particles containing a kind of atom and absorbing a light beam having a wavelength of 400 nm or less, (3) photopolymerization The photocurable coating composition characterized in that it contains 0.01 to 10 parts by weight. 2. The composition according to claim 1, further comprising (4) a silanol condensation catalyst in an amount of 0.01 to 10 parts by weight. 3. The composition according to claim 1, further comprising (5) an organic ultraviolet absorber in an amount of 1 to 50 parts by weight. 4. The composition according to claim 3, wherein the organic ultraviolet absorber is one or more selected from 2-hydroxybenzophenone-based, benzotriazole-based, cyanoacrylate-based and triazine-based compounds. 5. The photocurable coating composition according to claim 1, 2, 3, or 4 is applied to the surface of a base material, and the composition is irradiated with a high energy ray to apply the photocurable coating composition. A method for forming a coating film, comprising polymerizing a (meth) acrylic group and curing the coated product. 6. The cured product is irradiated with high energy rays and cured, and then the cured product is heated to condense the remaining OX groups in the composition and to perform secondary curing. The described method.