JPH0611767B2 - Photocurable composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photocurable composition that is cured by light, particularly, a photocurable composition that is cured by light, for example, ultraviolet rays to obtain adhesion to a substrate, surface abrasion resistance and The present invention relates to a photocurable composition that forms a film having a good surface appearance.

[Prior Art and Its Problems] For example, improving the hardness and abrasion resistance of the surface of plastic is extremely effective in improving the durability of the product and prolonging its life.

As a method for this, it has been conventionally known to irradiate a composition comprising an acrylate compound, a silane compound, silica and a photopolymerization initiator with ultraviolet rays to form a cured film on the surface of a substrate such as plastic. (JP-A-57-1
31214, JP-A-57-500984,
See JP-A-58-1756).

However, since the composition in the above method treats the surface of silica with a silane compound, the production process is complicated and expensive silane must be used.

The present invention has been made based on the above circumstances.

That is, an object of the present invention is to form a coating having good surface hardness, adhesion to a substrate, hot water resistance, abrasion resistance, heat crack resistance, and good surface appearance, and
An object of the present invention is to provide a composition that can be manufactured at low cost by a simple manufacturing process.

[Means for Achieving the Object] As a result of earnest research by the inventor in order to achieve the object, the α, β-unsaturated carboxylic acid compounds, colloidal silica, and photopolymerization initiator have a specific compounding ratio. The present invention was reached by finding that the composition blended in (1) forms a cured film having good adhesion to a substrate, hot water resistance, abrasion resistance, heat crack resistance and surface appearance.

That is, the outline of the present invention for achieving the above object is as follows: 100 parts by weight of α, β-unsaturated carboxylic acid compounds and colloidal silica 1 to 1 dispersed in a lower alcohol.
A photocurable composition comprising 400 parts by weight and 0.1 to 10 parts by weight of a photopolymerization initiator.

Examples of the α, β-unsaturated carboxylic acid compounds include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid, and ester derivatives of the α, β-unsaturated carboxylic acids. And the like, and the acrylic acid and its ester derivative are preferable.

As the ester derivative of acrylic acid, for example,
Methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, ethylhexyl acrylate, isodecyl acrylate, n-hexyl acrylate, stearyl acrylate, lauryl acrylate, tridecyl acrylate, phenoxyethyl acrylate, Ethoxyethyl acrylate, methoxyethyl acrylate, glycidyl acrylate, butoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-methoxyethoxyethyl acrylate, 2-ethoxyethoxyethyl acrylate, benzyl acrylate, cyclohexyl acrylate, dicyclopentenyl. Acrylate, dicyclope Butenyl oxy acrylate, dicyclopentadienyl acrylate, dicyclopentadiene ethoxy acrylate, methoxy diethylene glycol acrylate, ethoxy diethylene glycol acrylate, methoxy triethylene glycol acrylate,
Butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, 2-hydroxy-3-
Phenyloxypropyl acrylate, nonylphenol ethylene oxide adduct acrylate, nonylphenol propylene oxide adduct acrylate, octafluoropentyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, allyl acrylate, 1,3-butanediol Acrylate, 1,4-butanediol acrylate, 1,6-hexanediol acrylate, polyethylene glycol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, hydroxypivalate ester neo Pentyl glycol diacrylate, trimethylol B Panaji acrylate, bis (acryloxyethoxy) bisphenol A, bis (acryloxyethoxy) tetrabromobisphenol A, bis (acryloxy polyethoxy) bisphenol A, 1,
3-bis (hydroxyethyl) 5,5-dimethylhydantoin, 3-methylpentanediol acrylate,
α, ω-diacrylbisdiethylene glycol phthalate, trimethylolpropane triacrylate, pentaerythritol acrylate, pentaerythritol tetraacrylate, pentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, α, ω-tetraallyl bistrimethylolpropane tetrahydrophthalate, etc. , And inorganic acid esters such as 2-hydroxyethylacryloyl phosphate.

These α, β-unsaturated carboxylic acid compounds may be used alone, but it is preferable to use a mixture of two or more thereof, for example, two α, β-unsaturated carboxylic acid compounds. When using unsaturated carboxylic acid compounds, for example, a combination of pentaerythritol triacrylate and 2-hydroxyethyl acrylate, a combination of trimethylolpropane triacrylate and diethylene glycol diacrylate are preferred.

The colloidal silica is usually ultrafine particles having a particle size of about 10 to 30 mμ and exists as a colloidal liquid dispersed in a lower alcohol. Especially methanol, ethanol,
Colloidal silica dispersed in a lower alcohol such as propanol or isopropanol has a better dispersion in the composition of the present invention and improves the abrasion resistance of the cured film, and is therefore preferable to being dispersed in water. The concentration of colloidal silica dispersed in this lower alcohol is usually 1 to 50.
% By weight.

A dispersion of colloidal silica in such a lower alcohol is commercially available, for example, under the trade name of Oscal [manufactured by Catalysts & Chemicals Industry Co., Ltd.].

The photopolymerization initiator may be any one as long as it generates a radical by absorbing light energy, and examples thereof include acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone and p.
-Dimethylaminopropiophenone, benzophenone,
2-chlorobenzophenone, p, p'-dichlorobenzophenone, p, p'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether,
Benzoin-n-propyl ether, benzoin isobutyl ether, benzoin-n-butyl ether, benzylmethyl ketal, tetramethylimmonium monosulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, azobisisobutyronitrile, Benzoyl peroxide, di-t-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-
1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, methylbenzoyl formate, 2,2-diethoxyacetophenone, 4-N, N'-dimethylacetophenone, o -Isoamyl dimethylaminobenzoate and the like are mentioned, and among these, a ketone system such as 1- (4-isopropylphenyl) -2-sidroxy-2-methylpropan-1-one which absorbs ultraviolet energy and generates a radical. The compound can be preferably used.

The photocurable composition according to the present invention comprises 1 to 400 parts by weight of the colloidal silica, preferably 5 to 100 parts by weight, and 100 to 100 parts by weight of the α, β-unsaturated carboxylic acid compounds, and the photopolymerization initiation. It is important to add 0.1-10 parts by weight, preferably 1-8 parts by weight of the agent. In addition,
The blending amount of the colloidal silica means the weight part of the colloidal silica itself, and even when the colloidal silica dispersed in water, a lower alcohol or the like is used, the weight of the solvent is added to the weight of the colloidal silica. exclude.

When the content of the colloidal silica is less than 1 part by weight,
Sufficient abrasion resistance cannot be imparted to the film obtained by curing this photocurable composition, and if the amount of the colloidal silica compounded exceeds 400 parts by weight, the film will crack.

When the blending amount of the photopolymerization initiator is less than 0.1 parts by weight,
The curability of the photocurable composition is deteriorated, and when the blending amount exceeds 10 parts by weight, problems such as coloring of the coating film occur.

The photocurable composition of the present invention can be obtained by mixing the α, β-unsaturated carboxylic acid compounds, colloidal silica dispersed in a lower alcohol, and a photopolymerization initiator. The order of mixing the components is not limited, and the components may be mixed in any order. However, the above α, β-
It is preferable that the unsaturated carboxylic acid compounds and the colloidal silica dispersed in the lower alcohol are mixed and then the photopolymerization initiator is added thereto.

The photocurable composition according to the present invention is applied to the surface of a substrate,
When it is exposed to light, especially ultraviolet rays, it cures and forms a film.

As the base material on which the coating film can be suitably formed,
Examples thereof include plastics such as polycarbonate, polyester, polyetherimide, polyphenylene oxide and polymethylmethacrylate, and metals such as steel and aluminum. Of these substrates, polycarbonate is particularly preferable.

The photocurable composition can be applied to the surface of the substrate by, for example, a method using a coating bar, a doctor knife, a spray or the like, or a dipping method.

Light, in particular UV light, can be applied, for example, by means of a high-pressure mercury lamp.

EFFECTS OF THE INVENTION The photocurable composition according to the present invention can be obtained by simply mixing α, β-unsaturated carboxylic acid, colloidal silica dispersed in a lower alcohol, and a photopolymerization initiator. Therefore, it can be easily and inexpensively manufactured, and since the above-mentioned components are mixed in a specific mixing ratio, the adhesion between the base material and the coating film after photocuring, and the hot water resistance of the coating film after curing. And the resistance to heat cracking and abrasion resistance of the coating surface are good, and the surface appearance of the coating is smooth and beautiful without cracks.

EXAMPLES Next, the present invention will be described more specifically by showing Examples and Comparative Examples of the present invention.

(Examples 1 to 11) Colloidal silica dispersed in acrylate compounds of the types shown in Table 1 and isopropanol (concentration 30% by weight)
Were mixed at the compounding ratio shown in Table 1, and then 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1 was used as the photopolymerization initiator at the compounding ratio shown in Table 1.
-ON was added to obtain a photocurable composition.

This photocurable composition was applied to a polycarbonate plate having a thickness of 3 mm with a coating bar, and a high pressure mercury lamp having an output of 120 W / cm was irradiated at a distance of 150 mm at a conveyor speed of 2 m / min to form a cured film.

The characteristics of the obtained sample were evaluated by the following test methods.
The results are shown in Table 1.

The types of acrylic acid compound and colloidal silica used are as follows.

Acrylate compound A: Pentaerythritol triacrylate and 2-hydroxyethyl acrylate 4:
1 (weight ratio) mixture Acrylate compound B; pentaerythritol triacrylate and 2-hydroxyethyl acrylate 3:
2 (weight ratio) Mixture Acrylate compound C; 3: 2 (weight ratio) mixture of trimethylolpropane triacrylate and diethylene glycol diacrylate Acrylate compound D; Aronix UV-3700
[Toagosei Chemical Industry Co., Ltd., no photopolymerization initiator added]
(UV-Curable Acrylate Compound) Colloidal silica a; Oscal 1432 (average particle size
12 mμ) [Catalyst Chemical Co., Ltd.] Colloidal silica b; Oscal 1433 (average particle size)
18mμ) [Catalyst Chemical Co., Ltd.] Colloidal silica c; Oscal 1434 (average particle size
25 mμ) [Catalyst Kasei Kogyo Co., Ltd.] {Initial adhesiveness} Cross-cuts at equal intervals of 1 cm in length and width are put on the coating surface of the sample to form 100 eyes, and peeling operation with cellophane adhesive tape The initial adhesion was evaluated by the number of eyes that were not peeled off.

{Hot water resistance} 1 with cross-cut as in the case of initial adhesion
After forming 00 eyes and immersing the eyes in warm water at 85 ° C. for 3 hours, a peeling operation was performed with a cellophane adhesive tape, and the hot water resistance was evaluated by the number of eyes that were not peeled.

{Taber Wearability} Difference between "haze degree (%)" before wear test when "100 degree of haze" is measured with a Taber abrasion tester equipped with a CS-10 wear wheel and a load of 500 g. It was evaluated by.

{Heat-resistant crack resistance} The presence or absence of cracks on the surface 500 hours after the sample was placed in a dryer at 120 ° C was visually observed and evaluated.

{Appearance of coating film} The surface appearance of the cured coating film in the sample was visually observed and evaluated.

(Comparative Examples 1 to 4) A cured coating film was obtained in the same manner as in the above Example except that no colloidal silica was added, and the characteristics of this coating film were evaluated in the same manner as in the above Example. The results are shown in Table 1.

(Comparative Examples 5 and 6) A cured coating film was obtained in the same manner as in the above Example except that the compounding ratio of colloidal silica was outside the range specified in the present invention, and the characteristics of this coating film were evaluated in the same manner as in the above Example. did. In Comparative Example 6, a cured film was formed, but cracks occurred in the film.

(Comparative Examples 7 and 8) Comparative Examples 7 and 8 were carried out in the same manner as in the above Examples except that the compounding ratio of the photopolymerization initiator was outside the range specified in the present invention. In Comparative Example 7, a cured coating was formed, but the coating turned yellow. In Comparative Example 8,
The composition did not cure and no film formed.

Comparing the examples and comparative examples in Table 1, the cured film of the photocurable composition according to the present invention shows the adhesion to the substrate,
Both hot water resistance, abrasion resistance and surface appearance of the coating are excellent,
The cured coating of the composition containing no colloidal silica is inferior in adhesion to a substrate, hot water resistance and abrasion resistance, and even if an acrylate compound, colloidal silica and a photopolymerization initiator are both compounded. It can be seen that if the compounding ratio defined by the present invention is deviated, the characteristics of the cured film become poor.

Claims (1)

[Claims] 1. An α, β-unsaturated carboxylic acid compound 100.
A photocurable composition comprising 1 part by weight, 1 to 400 parts by weight of colloidal silica dispersed in a lower alcohol, and 0.1 to 10 parts by weight of a photopolymerization initiator.