JPS6262831A - Coating composition - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of a specific reaction mixture, a polyfunctional (meth)acrylate compound, a specific (meth)acryl compound and a photo-polymerization initiator, polymerizable and curable in air with ultraviolet irradiation and giving a coating film having excellent transparency and dyability, etc. CONSTITUTION:The objective composition can be produced by compounding (A) a reaction mixture of (i) a compound having >=2 mercapto groups per one molecule (e.g. pentaerythritol tetrathioglycolate) and (ii) a compound having >=1 epoxy group and >=1 acryloyl group per one molecule (e.g. acrylic acid 9,10-epoxidized oil) with (B) a polyfunctional (meth)acrylate compound (e.g. dipentaerythritol hexaacrylate), (C) a (methy)acryl compound having one triazine ring per one molecule and (D) a photo-polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention can be easily polymerized and cured in the air by ultraviolet rays.
This invention relates to a coating composition that provides a film with excellent abrasion resistance, transparency, dyeability, etc.

Problems to be Solved by Conventional Technologies and Inventions In recent years, plastic lenses are sometimes used in place of glass lenses due to their light weight, resistance to breakage, and high fashionability as they can be freely dyed. As is well known, the number of cases is increasing.

However, plastic lenses have the disadvantage of being easily scratched and therefore require surface hardening treatment.Furthermore, even after surface hardening treatment, a major feature of plastic lenses is that they can be easily dyed according to customer needs. It is necessary to have good stainability (without losing one).

As a conventional surface curing treatment method, for example, a method of thermally curing a silicone-based coating composition is known, but this method requires a long curing time and requires a temperature of 120° C. to achieve its original performance. Since this method requires a relatively high temperature, the heat resistance of the base material may become a problem, which is not preferable. Furthermore, when using silicone-based coating compositions, the resulting coating film may become cloudy or white unless the temperature and humidity of the atmosphere in which it is used are strictly controlled.
This is not preferable because the coating film performance may become unstable.

A method of forming a metal oxide coating film on the surface of a plastic lens by vacuum deposition is also known, but this method is not preferred because the resulting coating film cannot be dyed and has poor productivity.

Furthermore, a method of forming a coating film by curing a polyfunctional acrylic coating composition with ultraviolet light is also known, and this method is easy to handle, has high productivity, and the resulting coating film has excellent abrasion resistance. However, it is not preferable because the dyeing properties of the coating film are poor. If an attempt is made to impart dyeability to a coating film of a polyfunctional acrylic coating composition, the abrasion resistance of the coating film will deteriorate considerably, which is not preferable. There are also proposals to improve dyeability by using special dyes and dyeing methods, but these methods use special dyes and there are problems with the availability of dyes, so it is difficult to meet customer needs. There is a problem with not being able to respond quickly.

Therefore, the present invention eliminates the above-mentioned problems of the prior art, and creates a coating film that has excellent abrasion resistance and can be easily dyed with ordinary disperse dyes by irradiating ultraviolet rays in the air, while improving productivity. The aim is to develop coating compositions that are easily obtainable and easy to handle.

Means for Solving the Problems According to the invention, A, a compound (a) having at least two mercapto groups per molecule and at least one epoxy group and at least one acryloyl group per molecule; A coating consisting of a reaction mixture with compound (b), B, a polyfunctional (meth)acrylate compound, C, a (meth)acrylic compound having at least one triazine ring per molecule, and D, a photoinitiator. A composition for use is provided.

A compound having at least two mercapto groups per molecule used as a component of component A of the composition of the present invention (
As a), mention may be made of aliphatic or aromatic polymercaptans. Specific examples of darkening compounds include:
dipentene dimercaptan, ethylcyclohexyl dimercaptan, 1,6-hexane dimercaptan, mercapto compounds having carboxyl groups such as thioglycolic acid, β-mercaptopropionic acid or mercaptosuccinic acid and polyhydric alcohols such as trimethylolpropane, trimethyl Methylolethane, esterified product with pentaerythritol or dipentaerythritol;
Examples include a compound having a hydroxyl group at the carbon atom at the β-position relative to a mercapto group, a compound obtained by the reaction of an epoxy resin with hydrogen sulfide, and a compound obtained by the reaction of an epoxy resin with thioglycolic acid.

Examples of the compound (b) having at least one epoxy group and at least one acryloyl group used as other components of component A of the composition of the present invention include glycidyl acrylate, 9.10 epoxidized oleyl acrylate, , polyoxyalkylenated bisphenol-A-monoacrylate, neopentyl glycol diglycidyl ether monoacrylate, glycerol polyglycidyl ether mono- or diacrylate, trimethylolpropane polyglycidyl ether mono- or diacrylate,
Examples include sorbitol polyglycidyl ether mono-, di-, or triacrylate.

The reaction conditions for compounds (a) and (b) are not particularly limited, but the reaction can be easily carried out, for example, by stirring compounds (a) and (b) at room temperature or under heating. In this case, a suitable solvent (for example, acetone, methyl ethyl ketone, ethyl acetate, n-butyl acetate, ethyl propionate, ethanol, isopropanol, etc.) may be used as necessary.

Examples of the polyfunctional (meth)acrylate compound used as component B in the composition of the present invention include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, and polypropylene glycol. Diacrylate, butylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, diglycidyl bisphenol A
Diacrylate, ethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate,
Examples include polypropylene glycol dimethacrylate, butylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, and diglycidyl bisphenol A dimethacrylate.

Examples of the acrylic compound having a triazine ring used as component C in the composition of the present invention include compounds represented by the following formula.

(n is 0 to 30, R1 is CH3 or HSR2 is one, CH
2-CH2-1-CH2-CH (CH3+ or -CH2
CH(OH)CH2), Y is -CH2(-OR2
(m is O to 30, R2 is the same as above, R3 is hydrogen, an alkyl group, an aryl group, or an aralkyl group (preferably an alkyl group))] Used as component D in the composition of the present invention Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin isopropyl ether acetophenone, benzophenone, benzyl dimethyl ketal, and, if necessary, a suitable thermal initiator (
For example, common radical polymerization initiators such as benzoyl peroxide, diisopropyl peroxydicarbonate, and azobisisobutyronitrile can also be used in combination.

There is no particular limitation on the blending ratio of the compound (a) having a mercapto group and the compound (b) having an epoxy group and an acrylic group to obtain the above-described component A. The equivalent ratio of groups is 1:0.
2 to t: Desirably about O, S. When the equivalent weight of the mercapto group is less than this, the abrasion resistance of the coating film tends to be poor, and when the equivalent weight of the mercapto group is larger than this range, the dyeability of the coating film tends to be poor.

There is no particular limitation on the blending amount of component A, but 10% of the total blend
It is desirable to use about 3 to 15 parts by weight relative to 0 parts by weight. If the amount of component A is less than this, the dyeability of the coating film tends to be poor and the abrasion resistance also tends to be poor. On the other hand, if the amount of component A exceeds the above range, the hardness of the coating film tends to decrease and the pot life of the coating solution tends to deteriorate.

The amount of the (meth)acrylic compound having at least one triazine ring per molecule of component C in the composition of the present invention is not particularly limited, but is 10 to 50 parts by weight based on 100 parts by weight of the total composition. It is desirable to use it in moderation. If the amount of component C is less than this, the dyeability of the coating film tends to deteriorate, and if the amount of component C is more than this, the abrasion resistance of the coating film tends to deteriorate.

The photopolymerization initiator, which is component D of the composition of the present invention, is preferably used in an amount of about 0.01 to IO parts by weight based on 100 parts by weight of the total composition.

In addition to the above-mentioned essential ingredients, the composition according to the present invention includes:
A solvent can be used to lower the viscosity of the coating liquid so that it can be applied thinly, and other commonly used additives such as leveling agents, antistatic agents, ultraviolet absorbers, antioxidants, dye storage stabilizers, etc. can be added. can.

The coating composition according to the present invention obtained in this way can be coated using any conventional general coating method, such as Eva roller coating, flow coating, (UN, brush coating spin cord, spray coating, etc.). In addition, when the coating composition of the present invention contains or has a solvent,
For example, after evaporating the solvent by a suitable method such as ventilation, it is preferable to irradiate ultraviolet rays for curing.

There are no particular limitations on the thickness of the coating of the composition of the present invention, but it is generally about 1 μm to 1 μm, and in some cases, the coating may be applied to a base material after a primer has been applied thereto.

To cure the coating composition of the present invention, a mercury arc, a carbon arc, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a high frequency induced mercury lamp, a xenon flash lamp, etc. are used to cure the coating composition at room temperature or under heating. Any irradiation device capable of irradiating ultraviolet light can be used, and irradiation can also be carried out in air.

EXAMPLES Hereinafter, the present invention will be explained in more detail according to examples.
It goes without saying that the technical scope of the present invention is not limited to the scope of these Examples.

"Parts" in the examples indicate parts by weight. In addition, the performance test of the cured coating film was conducted as follows.

(a) Abrasion resistance test The surface of the coating was rubbed with #000 steel wool, and evaluated according to the following criteria.

A: Hardly any scratches B: Some scratches (C0: Many scratches (b) Appearance The surface condition, coloration, and transparency of the obtained coating film were examined by visual observation.

(c) Dyeing property: Add 0.2% dye (Diamond Coat Dye Brown D manufactured by Hattori Watch Co., Ltd.) and dyeing aids to warm water at 87°C, stir, and then soak for 5 minutes to dye. and 5 after staining
The difference in transmittance of 50 nm light is shown in %.

(d) Adhesion Use a knife to make 1 m square squares on the coating surface with 1001 [1] cellophane adhesive tape (manufactured by Nichiban Co., Ltd., cellophane tape)
was firmly attached and peeled off rapidly in a 90 degree direction, and the percentage of the first part that did not peel off compared to the whole was shown.

Example 1 24 parts of pentaerythol tetrathioglycolate and 32 parts of 9.10 acrylic acid epoxidized oleyl were dissolved in 28 parts of methyl ethyl ketone and stirred at room temperature for about 150 minutes to obtain a reaction mixture [hereinafter referred to as (A -1)].

7 parts of component (A-1) obtained as described above, 70 parts of dipentaerythritol hexaacrylate, and N.

N,N',N"-tetrakis(2-acryloylethoxymethyl)-N',N"-bis(2-methoxyethoxymethyl)melamine 30 parts, benzyldimethylkecool 0.8 part, surfactant (Dainippon Co., Ltd.) Ink Kagaku Kogyo Co., Ltd.: F-1440) 0.2 parts and ethyl acetate 300
parts were mixed thoroughly. A thoroughly washed diethylene glycol bisallyl carbonate lens was crushed in the resulting composition, then the lens was pulled up and dried with warm air at a temperature of 100°C for 10 minutes, and then irradiated with a 3KW high-pressure mercury lamp for 4 seconds to cure the coating. A membrane was created.

The results of performance evaluation of the obtained coating films are shown in Table 1.

Comparative Example 1 A cured coating film was obtained by carrying out the same operation as in Example 1 except that pentaerythritol tetrathioglycolate was not used in Example 1. The results of the performance evaluation of this coating film are shown in Table 1, and the coating film had poor abrasion resistance.

Comparative Example 2 A cured coating film was obtained in the same manner as in Example 1 except that the acrylic acid 9.10 epoxidized oleyl was not used in Example 1. The results of the performance evaluation of this coating film are shown in Table 1, and the coating film had poor dyeability.

Comparative Example 3 A cured coating film was obtained in the same manner as in Example 1 except that component (A-1) was omitted.

The results of the performance evaluation of the obtained coating film are shown in Table 1, and the coating film was poor in both abrasion resistance and dyeability.

Comparative Example 4 A cured coating film was obtained in the same manner as in Example 1 except that hexamethylol melasin tetraacrylate was omitted. The results of the performance evaluation of this coating film are shown in Table 1, and the coating film had no dyeing property.

As can be seen from the results in Table 1, only the reaction mixture of a compound having a mercapto group and a compound having an epoxy group and an acrylic group, and the composition containing an acrylic compound having a triazine ring had excellent abrasion resistance and dyeability. It is clear that a coating film with a high quality is obtained.

Example 2 7 parts of compound (A-1) obtained in the same manner as in Example 1, 65 parts of dipentaerythritol hexaacrylate, 15 parts of pentaemeritol triacrylate, N,N'-bis(2-acryloylethoxymethyl) )-N, N', N
",N"-tetrakis(2-methoxyethoxymethyl)
The same operation as in Example 1 was carried out using a composition in which 20 parts of melamine, 1 part of benzyl dimethyl ketal, 0.2 parts of the same surfactant as in Example 1, and 300 parts of ethyl acetate were mixed.

The results of the performance evaluation of the obtained coating film are shown in Table 1, and the same results as in Example 1 were obtained.

Example 3 The same operation as in Example 1 was performed except that pentaerythritol tetrathioglycolate in Example 1 was replaced with trimethylolpropane trithioglycolate.

The results of the performance evaluation of the obtained coating film are shown in Table 1, and a good coating film similar to that of Example 1 was obtained.

A cured coating film was obtained in the same manner as in Example 1 except that the 9,10 epoxidized oleyl acrylate in Example 1 was replaced with L6 hexanediol diglycidyl ether monoacrylate.

The results of the performance evaluation of the obtained coating film are shown in Table 1, and an excellent coating film similar to that of Example 1 was obtained.

Table 1

Claims (1)

[Claims] 1. A. A compound (a) having at least two mercapto groups per molecule and a compound (b) having at least one epoxy group and at least one acryloyl group per molecule. A coating composition comprising a reaction mixture, B, a polyfunctional (meth)acrylate compound, C, a (meth)acrylic compound having at least one triazine ring per molecule, and D, a photopolymerization initiator.