JP2022049577A - Active energy ray-curable coating composition for coating layer for back of mirror - Google Patents

Abstract

To provide an active energy ray-curable coating composition for a coating layer for the back of a mirror, wherein a cured film of it has high adhesion to a coating layer for the back of a mirror, in particular a melamine-containing layer, the adhesion is not impaired even when used at high humidity, and it also exhibits superior water resistance and acid resistance.SOLUTION: An active energy ray-curable coating composition for a coating layer for the back of a mirror, contains the following components (A), (B) and (C). Component (A): a compound having an oxetane ring, (B): a compound having an oxirane ring, (C): a compound to induce cationic polymerization by irradiation with an active energy ray.SELECTED DRAWING: None

Description

The present invention relates to an active energy ray-curable coating agent composition for a paint layer on the back surface of a mirror. The cured film of the composition of the present invention is excellent in adhesion, water resistance and acid resistance even when a mirror is used in an environment of high humidity or direct contact with water, and is a product around water such as kitchens and bathrooms. It can be suitably used as a protective coating agent for a mirror backing paint layer used in, particularly a melamine-containing layer, and belongs to these technical fields.

The mirror forms a silver film by silver plating called "silvering" on the back surface of the plate glass, and in order to protect the silver film from moisture etc., a copper film by copper plating is formed on the silver film, and further. It was manufactured by forming a protective coating film (hereinafter referred to as "backside paint layer") on top of this using a paint called a backing paint, and a backing paint containing melamine resin or the like was used. ..

Melamine resin is a thermosetting resin obtained by the reaction of melamine and formaldehyde, and is excellent in electrical properties, mechanical strength, heat resistance, chemical resistance, weather resistance, coloring property, etc. It is used for various purposes such as molding materials, adhesives and paints, and is also used as a backing paint for the above-mentioned mirrors.
The mirror backing paint containing the melamine resin includes a melamine resin, a resin mixed with an epoxy resin, a thermosetting acrylic resin or an alkyd resin, a pigment, and a pigment dispersant, and if necessary, an organic solvent, the above-mentioned A curing agent for a thermosetting resin, a paint containing other additives, and the like are known.

However, the backside paint layer with the conventional backing paint cannot sufficiently suppress the corrosion by acid, and in mirrors installed in high humidity or in direct contact with water such as bathrooms, dressing rooms, and washrooms. The silver mirror surface film may be corroded by highly acidic chemicals. Therefore, for mirrors installed in a high humidity environment, it has been desired to develop a backing coating material capable of forming a back surface coating layer having excellent acid resistance that is not easily eroded by acid as well as water resistance.

As the backing coating composition, an alkyd melamine resin or the like was used as the melamine resin, but in order to solve the above problems, paints other than these have also been studied.
For example, it contains a backing paint composition (Patent Document 1) in which the metal content in the paint is a specific ratio, a thermosetting resin such as an epoxy resin or an alkyd resin, a pigment, and a dispersant, and the dispersant contains an acid group. A backing coating composition containing an amino group-containing polymer that does not exist (Patent Document 2) has been studied.
However, in the conventional backing coating composition, the obtained coating layer has an insufficient effect of preventing erosion by the acid described above.

On the other hand, the active energy ray-curable composition can be cured by irradiating it with active energy rays such as ultraviolet rays, visible rays and electron beams for a very short time, and has high productivity. Therefore, inks and coating agents for various substrates are used. It is widely used as.
It has also been studied to use such an active energy ray-curable composition as a backing paint for a mirror or as a coating agent composition for protecting the back paint layer of a mirror (Patent Documents 3 and 4). ..
However, in the active energy ray-curable coating agent compositions described in these documents, the cured film has insufficient adhesion to the back surface coating layer of the mirror, particularly the melamine-containing layer, and is also water resistant and acid resistant. Was enough.

Japanese Unexamined Patent Publication No. 2007-050056 Japanese Patent No. 5733212 Japanese Unexamined Patent Publication No. 6-340725 Japanese Unexamined Patent Publication No. 2002-02635

The present inventors have excellent adhesion to the back surface coating layer of the mirror, particularly the melamine-containing layer, the cured film does not impair the adhesion even when used under high humidity, and further water resistance and acid resistance. In order to find an active energy ray coating agent curable composition for the back surface paint layer of a mirror, we conducted diligent studies.

As a result of diligent studies to solve the above problems, the present inventors have obtained an active energy ray-curable composition containing a compound having an oxetane ring, a compound having an oxylan ring, and a compound that initiates cationic polymerization by an active energy ray. By using the compound, it has been found that the adhesion to the backing coating layer of the mirror, particularly the melamine-containing layer is good, and the water resistance and the acid resistance are excellent, and the present invention has been completed.
Hereinafter, the present invention will be described in detail.

According to the composition of the present invention, the cured film has excellent adhesion to the back surface coating layer of the mirror, particularly to the melamine-containing layer, and is also excellent in water resistance and acid resistance.
Therefore, the composition of the present invention can be suitably used as a protective coating agent for a mirror backing paint layer used in products around water such as kitchens and bathrooms, particularly a melamine-containing layer.

The present invention relates to an active energy ray-curable coating agent composition for a back surface coating layer of a mirror containing the following components (A), (B) and (C).
Component (A): Compound having an oxetane ring (B) Component: Compound having an oxylan ring (C) Component: Compound that initiates cationic polymerization by irradiation with active energy rays The following are essential components (A) and (B). The components, (C) components, other components, usage methods, etc. will be described.

1. 1. Component (A ) Component (A) is a compound having an oxetane ring.
The component (A) is a component for imparting good curability to the composition and imparting good flexibility to the cured film to prevent cracking or peeling of the coating agent even if an impact is applied to the member. be.

As the component (A), both a compound having one oxetane ring [hereinafter referred to as "(A1) component"] and a compound having two or more oxetane rings [hereinafter referred to as "(A2) component"] are used. Can be used.

As the component (A1), various compounds can be used as long as they are compounds having one oxetane ring.
As a preferable compound of the component (A1), a compound represented by the following formula (1) can be mentioned.

Here, in the formula (1), Z means an oxygen atom or a sulfur atom. R ¹ means a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, a frill group, or a thienyl group. R ² means an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an aryl group, an alkylcarbonyl group having 1 to 6 carbon atoms, or an alkoxycarbamoyl group having 1 to 6 carbon atoms. do.
Examples of the alkyl group having 1 to 6 carbon atoms in R ¹ and R ² include a methyl group, an ethyl group, a propyl group, a butyl group and the like.
Examples of alkenyl groups having 1 to 6 carbon atoms in R ² are 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 1-butenyl group, 2-butenyl group, and 3-butenyl. The group etc. can be mentioned.
Examples of the aryl group in R ¹ and R ² include a phenyl group, a benzyl group, a fluorobenzyl group, a methoxybenzyl group, a phenoxyethyl group and the like.
Examples of the alkylcarbonyl having 1 to 6 carbon atoms in R ² include a propylcarbonyl group, a butylcarbonyl group, a pentylcarbonyl group and the like.
Examples of the alkylcarbamoyl group having 1 to 6 carbon atoms in R ² include an ethoxycarbamoyl group, a propylcarbamoyl group, a butylcarbamoyl group, and a butylpentylcarbamoyl.

In the present invention, the compounds in which Z, R ¹ and / or R ² are represented below in the above formula (1) are preferable.
As Z, a compound which is an oxygen atom is preferable. As R ¹ , a compound having a lower alkyl group is preferable, and a compound having a methyl group or an ethyl group is preferable. Further, as R ² , a compound having a hydrogen atom, a butyl group, a 2-ethylhexyl group, or a benzyl group is preferable.

Specific examples of the preferable compound represented by the formula (1) include 3-ethyl-3-hydroxymethyloxetane, which is a compound in which Z is an oxygen atom, R ¹ is a lower alkyl group, and R ² is a hydrogen atom. Can be mentioned.
Specific examples of the preferable compound represented by the formula (1) are 3-ethyl-3-butyloxymethyloxetane in which Z is an oxygen atom, R ¹ is a lower alkyl group, and R ² is an alkyl group. , 3-Ethyl-3-hexyloxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-dodecyloxymethyloxetane, 3-ethyl-3-octadecyloxymethyl Oxetane, 3-Ethyl-3-Cyclohexyloxymethyl Oxetane, 3-Ethyl-3- (Phenoxymethyl) Oxetane, 3-Ethyl-3- (Nonylphenoxymethyl) Oxetane, 3-Ethyl-3- (Phenylmethoxymethyl) Oxetane , 2-[(3-Ethyloxetane-3-yl) methoxy] biphenyl, 4-[(3-ethyloxetane-3-yl) methoxy] biphenyl and the like.

As the component (A1), a compound having one oxetane ring and one hydroxyl group is more preferable because it has excellent adhesion to a substrate.
As a specific example of the compound having one oxetane ring and one hydroxyl group, in the formula (1), Z is an oxygen atom, R ¹ is a lower alkyl group, and R ² is a hydrogen atom. -Ethyl-3-hydroxymethyloxetane and the like can be mentioned.

The component (A1) is commercially available, 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol) [Aron oxetane OXT-101 manufactured by Toagosei Co., Ltd.], and 2-ethylhexyl oxetane [Aron manufactured by Toagosei Co., Ltd.]. Oxetane OXT-212] and the like.

As the component (A2), various compounds can be used as long as they are compounds having two or more oxetane rings. Specific examples of the component (A2) include the compounds exemplified in JP-A-11-246647.

Preferred specific examples of the component (A2) include, for example, the following compounds.
3-Ethyl-3-[(3-ethyloxetane-3-yl) methoxymethyl] oxetane,
1,4-Bis [(3-ethyloxetane-3-yl) methoxymethyl] benzene,
1,4-Bis [(3-ethyloxetane-3-yl) methoxy] benzene,
1,3-Bis [(3-ethyloxetane-3-yl) methoxy] benzene,
1,2-bis [(3-ethyloxetane-3-yl) methoxy] benzene,
4,4'-Bis [(3-ethyloxetane-3-yl) methoxy] biphenyl,
2,2'-Bis [(3-ethyloxetane-3-yl) methoxy] biphenyl,
3,3', 5,5'-tetramethyl-4,4'-bis [(3-ethyloxetane-3-yl) methoxy] biphenyl,
2,7-Bis [(3-ethyloxetane-3-yl) methoxy] naphthalene,
Bis [4-{(3-ethyloxetane-3-yl) methoxy} phenyl] methane,
Bis [2-{(3-ethyloxetane-3-yl) methoxy} phenyl] methane,
2,2-Bis [4-{(3-ethyloxetane-3-yl) methoxy} phenyl] propane,
An etherified modified product of novolak-type phenol-formaldehyde resin with 3-chloromethyl-3-ethyloxetane,
3 (4), 8 (9) -bis [(3-ethyloxetane-3-yl) methoxymethyl] -tricyclo [5.2.1.0 ^2,6 ] decane,
2,3-bis [(3-ethyloxetane-3-yl) methoxymethyl] norbornane,
1,1,1-Tris [(3-ethyloxetane-3-yl) methoxymethyl] propane,
1-Butoxy-2,2-bis [(3-ethyloxetane-3-yl) methoxymethyl] butane,
1,2-bis [{2- (3-ethyloxetane-3-yl) methoxy} ethylthio] ethane,
Bis [{4- (3-ethyloxetane-3-yl) methylthio} phenyl] sulfide,
1,6-bis [(3-ethyloxetane-3-yl) methoxy] -2,2,3,3,4,5,5-octafluorohexane,
3-[(3-Ethyloxetane-3-yl) methoxy] Hydrolyzed condensate of propyltriethoxysilane,
Tetrakis [(3-ethyloxetane-3-yl) methyl] silicate condensate, etc.

As the component (A2), a compound having two oxetane rings is preferable, and specific examples thereof include the compounds mentioned above.

The component (A2) is commercially available, and xylylene bis oxetane [Aron oxetane OXT-121 manufactured by Toagosei Co., Ltd.] and 3-ethyl 3 {[(3-ethyl oxetane-3-yl) methoxy] methyl} oxetane. [Aron Oxetane OXT-221 manufactured by Toagosei Co., Ltd.] and the like can be mentioned.

As the component (A), only one of the above compounds may be used, or two or more of them may be used in combination.
Further, as the component (A), only the component (A1) can be used, only the component (A2) can be used, or the component (A1) and the component (A2) can be used in combination.

As the component (A1), a compound having one oxetane ring and one hydroxyl group is preferable as described above because the adhesion to the substrate can be further strengthened, but the water resistance of the cured film is preferable. When it is desired to further enhance the property, it is preferable to use the component (A2) in combination in order to lower the swelling ratio of the cured film by water.
The ratio of the components (A1) and (A2) in 100% by weight of the total amount of the components (A1) and (A2) can be in any range, depending on the type of the back surface paint layer of the mirror as the base material. It may be adjusted, and specifically, (A1) component 3 to 80% by weight and (A2) component 97 to 20% by weight are preferable, (A1) component 3 to 50% by weight and (A2) component 97 to 50% by weight. % Is more preferable.

2. 2. Component (B ) Component (B) is a compound having an oxylan ring.
The component (B) is a component that can increase the strength of the cured film and improve the water resistance by being contained in the composition.
As the component (B), any of a monomer, an oligomer, and a polymer can be used.

Specific examples of the component (B) include conventionally known aromatic epoxy compounds, aliphatic epoxy compounds, and alicyclic epoxy compounds.

The aromatic epoxy compound is a polyhydric phenol having at least one aromatic nucleus, or a di or polyglycidyl ether produced by the reaction of an alkylene oxide adduct thereof with epichlorohydrin.
Specific examples of the aromatic epoxy compound include bisphenol type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of brominated bisphenol A;
Diglycidyl ether of alkylene oxide adduct of bisphenol, diglycidyl ether of alkylene oxide adduct of bisphenol F, diglycidyl ether of alkylene oxide adduct of brominated bisphenol AF, etc. ;and,
Examples thereof include a novolak type epoxy resin such as a phenol novolac type epoxy resin and a cresol novolak type epoxy resin.
Examples other than the above include biphenyl type epoxy resin, hydroquinone diglycidyl ether, resorcin diglycidyl ether, terephthalic acid diglycidyl ester, phthalic acid diglycidyl ester, styrene-butadiene copolymer epoxidized product, and styrene-isoprene copolymer. Examples thereof include the epoxidized product of the above, and an addition reaction product of the terminal carboxylic acid polybutadiene and the bisphenol A type epoxy resin.
Examples of the above-mentioned alkylene oxide include ethylene oxide and propylene oxide.

Here, the epoxy resin refers to a compound or polymer that has an average of two or more epoxy groups in the molecule and is cured by a reaction.
According to conventions in the art, herein, a monomer may be an epoxy resin as long as it has two or more curable epoxy groups in the molecule.

Examples of the alicyclic epoxy compound include compounds obtained by epoxidizing at least one compound having a cycloalkene ring such as cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Be done.
Specific examples of the alicyclic epoxy compound include dicyclopentadiendioxide, limonendioxide, 4-vinylcyclohexenedioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,). Examples thereof include compounds having at least one epoxidized cyclohexyl group such as 4-epoxycyclohexylmethyl) adipate, and di or polyglycidyl ether of hydrogenated bisphenol A or an alkylene oxide adduct thereof.

Examples of the aliphatic epoxy compound include an aliphatic alcohol or a di or polyglycidyl ether of an alkylene oxide adduct thereof.
Specific examples of the compound include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, and diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol;
Polyglycidyl ethers of polyhydric alcohols such as di or triglycidyl ethers of glycerin or its alkylene oxide adduct;
Examples thereof include diglycidyl ether of polyethylene glycol or an alkylene oxide adduct thereof, and polyglycidyl ether of polyalkylene glycol such as diglycidyl ether of polypropylene glycol or an alkylene oxide adduct thereof.
Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.
Further, in addition to these compounds, monoglycidyl ethers of aliphatic higher alcohols, which are monomers having one oxylan ring in the molecule, phenols, cresols, or monoglycidyl ethers of these alkylene oxide adducts can also be used. can.

As the component (B), a compound having two or more oxylan rings is preferable because the surface hardness of the obtained cured film is good and the chemical resistance, acid resistance, and water resistance are excellent.
Further, among such compounds, aromatic epoxy compounds are preferable, and epoxy resins having a bisphenol skeleton are more preferable. Examples of the bisphenol skeleton include bisphenol A, bisphenol F, bisphenol P, and bisphenol Z.

As the component (B), only one of the above compounds may be used, or two or more of them may be used in combination.

As for the content ratio of the component (A) and the component (B), 5 to 95% by weight of the component (A) and 95 to 95% by weight of the component (B) in the total of 100% by weight of the component (A) and the component (B). It is preferably contained in an amount of 5% by weight, more preferably 10 to 30% by weight of the component (A) and 90 to 70% by weight of the component (B).
By setting the content ratios of the component (A) and the component (B) as described above, the curing rate of the composition can be made good, and the adhesion to the substrate can be made excellent.

3. 3. Component (C ) Component (C) is a compound that initiates cationic polymerization by irradiation with active energy rays, a compound that produces cation species or Lewis acid by irradiation with active energy rays, and is usually used as a photocationic polymerization initiator. It is a known compound.
As the component (C), various compounds known as photocationic polymerization initiators can be used, and onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, and iron-allene. Examples thereof include complexes and the like, and onium salts such as aromatic iodonium salts and aromatic sulfonium salts are preferable.
Specific examples of the aromatic iodonium salt and the aromatic sulfonium salt in the component (C) include the compounds exemplified in JP-A-11-246647.

Preferred specific examples of the component (C) include, for example, the following compounds.
Examples of the aromatic iodonium salt include the following compounds.
Diphenyliodonium Tetrakis (Pentafluorophenyl) Borate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium hexafluoroantimonate,
Di (4-nonylphenyl) iodonium hexafluorophosphate, etc.

Examples of the aromatic sulfonium salt include the following compounds.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
Diphenyl [4- (Phenylthio) Phenyl] Sulfonium Hexafluorophosphate,
Diphenyl [4- (Phenylthio) Phenyl] Sulfonium Hexafluoroantimonate,
4,4'-Bis (diphenylsulfonio) diphenylsulfide bishexafluorophosphate,
4,4'-Bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate,
4,4'-Bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluorophosphate,
7- [di (p-toluyl) sulfonate] -2-isopropylthioxanthone hexafluoroantimonate,
7- [di (p-toluyl) sulfonate] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,
4-Phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate,
4- (p-tert-Butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate,
4- (p-tert-Butylphenylcarbonyl) -4'-di (p-toluyl) sulfonate-diphenylsulfide Tetrakis (pentafluorophenyl) borate and the like.

Examples of the aromatic diazonium salt include the following compounds.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate, etc.

Examples of the iron-allene complex include the following compounds and the like.
Xylene-Cyclopentadienyl Iron (II) Hexafluoroantimonate,
Cumene-Cyclopentadienyl Iron (II) Hexafluorophosphate,
Xylene-Cyclopentadienyl Iron (II) -Tris (Trifluoromethylsulfonyl)
Metanide etc.

As the component (C), one kind of the above-mentioned compound may be used alone, or two or more kinds may be used in combination.

As the component (C), a commercially available product can be used.
Specific examples thereof include, for example, "Kayarad PCI-220" and "Kayarad PCI-620" [all manufactured by Nippon Kayaku Co., Ltd.] under their respective product names.
"UVI-6992" (manufactured by Dow Chemical),
"ADEKA CORPORATION SP-150", "ADEKA CORPORATION SP-170" [above, manufactured by ADEKA CORPORATION],
"CI-5102", "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S", "CIP-2064S" [above, manufactured by Nippon Soda Corporation],
"DPI-101", "DPI-102", "DPI-103", "DPI-105", "MPI-103", "MPI-105", "BBI-101", "BBI-102", "BBI" -103 "," BBI-105 "," TPS-101 "," TPS-102 "," TPS-103 "," TPS-105 "," MDS-103 "," MDS-105 "," DTS-102 " , "DTS-103" [above, manufactured by Midori Kagaku Co., Ltd.],
"PI-2074" (manufactured by Rhodia),
"Omnicat250", "OmnicatPAG103", "OmnicatPAG108", "OmnicatPAG121", "OmnicatPAG203" [above, manufactured by IGM RESINS B.V.),
Examples thereof include "CPI-100P", "CPI-101A", "CPI-200K", "CPI-210S" [all manufactured by Sun Appro Co., Ltd.] and the like.
Among these, in particular, "UVI-6992" manufactured by Dow Chemical Co., Ltd., "CPI-100P" manufactured by San Apro Co., Ltd., and "CPI-101A" containing diphenyl [4- (phenylthio) phenyl] sulfonium as a cation component. , "CPI-200K", "CPI-210S" are preferable.

The content ratio of the component (C) is preferably 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total of the components (A) and (B). The weight part is more preferable.
Here, the active ingredient means the solid content of the component (C), which is often used as a solution of an organic solvent.
By setting this content ratio, it is possible to obtain a curing rate that can achieve industrially sufficient productivity even in a composition having a large number of parts of the component (B) having a relatively slow polymerization rate. On the other hand, if the content ratio of the component (C) exceeds 10 parts by weight, problems such as corrosion may occur depending on the substrate or product to be coated due to the influence of the acid contained in the component (C).
Further, depending on the type of the component (C), a solution diluted with an organic solvent [hereinafter referred to as "component (C) solution"] may be used, but in this case, the concentration of the active ingredient is tentatively 50% by weight. If so, the amount to be added may be doubled. Even when using the component solution (C), if the blending amount is large, the amount of organic solvent brought in from the component solution (C) will increase, and a separate drying step will be required, or if it is cured without drying, it will be organic. Since the appearance may be poor due to the influence of the solvent, it is preferable to adjust the content ratio in consideration of the degree of curability and the deterioration of the performance of the cured film.

4. Active energy ray-curable coating agent composition for the back surface coating layer of a mirror The present invention is an active energy ray-curable coating agent composition for the back surface coating layer of a mirror containing the components (A), (B), and (C). Is.
Examples of the method for producing the composition include a method of stirring and mixing the above-mentioned components (A), (B) and (C), and other components described below as necessary according to a conventional method.
In this case, it may be heated and stirred as needed. The temperature in the case of heating, stirring and mixing is preferably in the range of 20 to 70 ° C.

The viscosity of the composition may be appropriately set according to the intended use and purpose. The viscosity is preferably 100 to 20,000 mPa · s, and more preferably 200 to 8,000 mPa · s.
In the present invention, the viscosity means a value measured at 25 ° C. with an E-type viscometer (cone plate type viscometer).

The composition of the present invention requires the above-mentioned components (A), (B) and (C), but can be used for adjusting the coatability, adjusting the adhesion to the substrate, and imparting other design properties. For the purpose, various ingredients can be blended as needed.
Preferred other components include a polymer [hereinafter referred to as "(D) component"], a silane coupling agent [hereinafter referred to as "(E) component"], and a photoradical polymerization initiator [hereinafter referred to as "(F) component". ] Other ingredients other than these can be blended.
Hereinafter, the components (D) to (F) will be described.
In the following, the component (A) and the component (B) are referred to as "curable component".
Further, as the other components described later, only one of the exemplified compounds may be used, or two or more of them may be used in combination.

4-1. Component (D) The polymer, which is the component (D), can be used as a thickener for the purpose of improving the water resistance and chemical resistance of the cured film, adjusting the leveling during coating, and the like. ..
As the component (D), any component can be used as long as it does not significantly inhibit cationic polymerization.

As a specific example, various (meth) acrylic polymers can be used.
Further, a polymer having (meth) acrylate as an essential constituent monomer unit and a weight average molecular weight (hereinafter referred to as “Mw”) of 1,000 to 30,000 is low in viscosity and easy to formulate. preferable.
In the present invention, Mw means a value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter referred to as “GPC”) into polystyrene.
The glass transition point (hereinafter referred to as "Tg") of the component (D) is preferably in the range of −85 ° C. to 120 ° C., and more preferably in the range of −80 ° C. to 100 ° C.
In the present invention, Tg means a value measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC), and is a value at the glass transition temperature midpoint (Tmg) in the ΔT-temperature curve. Means.

Further, as the component (D), a polymer produced by high-temperature polymerization that does not require a large amount of chain transfer agent or polymerization initiator is preferable, and a weight produced by high-temperature continuous polymerization at a temperature of 160 to 350 ° C. Coalescence is more preferred.
The polymer obtained by high-temperature continuous polymerization in the component (D) is commercially available, and is ARUFON UP-1000 (Mw: 3,000, Tg: -77 ° C.), ARUFON UP-1010 (Mw) manufactured by Toagosei Co., Ltd. : 1,700, Tg: -31 ° C), ARUFON UP-1020 (Mw: 2,000, Tg: -80 ° C), ARUFON UP-1021 (Mw: 1,600, Tg: -71 ° C), ARUFON UP -1061 (Mw: 1,600, Tg: -60 ° C), ARUFON UP-1080 (Mw: 6,000, Tg: -61 ° C), ARUFON UP-1110 (Mw: 2,500, Tg: -64 ° C) ), ARUFON UP-1170 (Mw: 8,000, Tg: −57 ° C.), ARUFON UP-1190 (Mw: 1,700, Tg: −50 ° C.).
Further, as a copolymer having a hydroxyl group, ARUFON UH-2041 (Mw: 2,500, Tg: -50 ° C), ARUFON UH-2190 (Mw: 6,000, Tg: -47 ° C), ARUFON UHE-2012 ( Mw: 5,800, Tg: 20 ° C.) and ARUFON UH-2170 (Mw: 14,000, polydispersity: 3.5, Tg: 60 ° C.) and the like.
In addition, (meth) acryloyl resin having a carboxyl group, (meth) acryloyl resin having an epoxy group, and (meth) acryloyl resin having an alkoxysilyl group can also be used. Specifically, ARUFON UC-3510 (Mw: 2,000, Tg: -50 ° C), ARUFON UG-4010 (Mw: 2,900, Tg: -57 ° C), ARUFON US-6100 (Mw: 2,) 500, Tg: −58 ° C.) and the like.

When various polymers are used as the component (D), the structure is not particularly specified.

4-2. (E) Component The composition of the present invention may further contain the component (E) (silane coupling agent) for the purpose of improving the adhesion to the substrate.

The component (E) is not particularly limited, and known components can be used.
As a preferable specific example of the silane coupling agent,
A (meth) acryloyl group-containing silane coupling agent such as 3- (meth) acryloxypropyltrimethoxysilane;
Vinyl group-containing silane coupling agents such as vinyltriacetoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane;
Allyl group-containing silane coupling agent such as allyltrimethoxysilane;
Cyclic ether groups such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane Containing silane coupling agent;
N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane , 3-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, etc. Amino group-containing silane coupling agents; and mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane.

Among the above, a compound having an oxylan ring in the molecule is preferable because it can be cationically copolymerized.
Among these compounds, a silane coupling agent having a cationically polymerizable group is preferable because it is chemically incorporated into the cured film by cationic copolymerization with the component (A) and the component (B).
Examples of the silane coupling agent having a cationically polymerizable group include the above-mentioned cyclic ether group-containing silane coupling agent, and further, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and the like. And 3-glycidoxypropyltriethoxysilane are particularly preferred.
The content ratio of the component (E) is preferably 10 parts by weight or less with respect to 100 parts by weight of the curable component. Since the desorption reaction of the component (E) occurs in the process of the reaction, if it exceeds 10 parts by weight, bubbles may be generated when the obtained cured film is immersed in warm water, and the appearance of the cured film may be impaired.

4-3. Component (F) As the component (F) in the present invention, various known photoradical polymerization initiators can be used.
The component (F) is used for the purpose of increasing the curing rate when an aromatic iodonium salt is used as the component (C).

As the component (F), various photoradical initiators can be used, but a photocleavable photoradical polymerization initiator is preferable because radicals can be efficiently generated regardless of the compounding composition.
Specific examples of the photocleavable photoradical polymerization initiator in the component (F) include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenylketone, and 2-hydroxy-2-. Methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-methyl-1- [4-] (Methylthio) Phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butane-1-one, diethoxyacetophenone, oligo {2-hydroxy- 2-Methyl-1- [4- (1-methylvinyl) phenyl] propanone} and 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methyl Acetphenone compounds such as propane-1-one; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphinoxide, bis (2,6-dimethoxybenzoyl)- Phosfin oxide-based compounds such as 2,4,4-trimethylpentylphosphine oxide;
Benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; titanosen-based compounds and the like can be mentioned.

The content ratio of the component (F) is preferably 0.01 to 10 parts by weight, more preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the total amount of the curable component. It is particularly preferable that the amount is up to 5 parts by weight. Within the above range, the curability of the composition is excellent, and the scratch resistance of the obtained cured film is excellent.

4-4. Other components other than the above As the other components other than the above, known additives used for coating agents can be used.
Specific examples thereof include organic solvents, ultraviolet absorbers, light stabilizers, acidic substances, inorganic particles, antioxidants, surface modifiers, pigments, dyes, tackifiers, polymerization inhibitors, and the like. Be done.
Hereinafter, among other components, organic solvents, ultraviolet absorbers, light stabilizers, acidic substances, inorganic particles, antioxidants, and surface modifiers will be described.

<Organic solvent>
The composition of the present invention can be used without a solvent, but various organic solvents can be used for the purpose of adjusting the coating viscosity and the film thickness.
Specific examples of the organic solvent include alcohol compounds such as methanol, ethanol, isopropanol and butanol; alkylene glycol monoether compounds such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether; acetone alcohols such as diacetone alcohol; benzene, toluene and xylene. Aromatic compounds such as; ester compounds such as propylene glycol monomethyl ether acetate, ethyl acetate, butyl acetate; ketone compounds such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ether compounds such as dibutyl ether; and N-methylpyrrolidone and the like. ..

Since it is of great significance that the present invention does not require a drying step, it is preferable not to use an organic solvent, and even if it is used, it is necessary to use a minimum blending amount. When it is unavoidably used, the content ratio is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total amount of the composition.

<UV absorber>
Specific examples of the ultraviolet absorber include 2- [4-[(2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl)-. 1,3,5-triazine, 2- [4-[(2-hydroxy-3-tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1, 3,5-Triazine, 2- [4-[(2-Hydroxy-3- (2-ethylhexyloxy) propyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2-hydroxy-4-butyloxyphenyl) -6- (2,4-bisbutyroxyphenyl) -1,3,5-triazine, 2-( 2-Hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine and other triazine UV absorbers; 2- (2H-benzo) Triazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole, 2- [2-hydroxy -5- (2- (meth) acryloyloxyethyl) phenyl] -2H-benzotriazole-based ultraviolet absorbers such as benzotriazole; benzophenone-based ultraviolet absorbers such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone Agents, cyanoacrylate-based ultraviolet absorbers such as ethyl-2-cyano-3,3-diphenylacrylate, octyl-2-cyano-3,3-diphenylacrylate, ultraviolet rays such as titanium oxide particles, zinc oxide particles, tin oxide particles, etc. Examples include inorganic particles that absorb phenyl group. Among the compounds, a benzotriazole-based ultraviolet absorber is particularly preferable.
The content ratio of the ultraviolet absorber is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and 0. It is more preferably 1 to 2 parts by weight.

In general, it is preferable not to use an ultraviolet absorber for the component (C) because the absorption wavelength is short. However, when an ultraviolet absorber is unavoidably used, the photosensitizer is such that the component (C) acts even at a long wavelength. It is preferable to use an agent in combination.
Specific examples of the photosensitizer include thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone, and anthracene derivatives such as 9,10-dibutoxyanthracene and 9,10-bis (acyloxy) anthracene. ..

<Light stabilizer>
As the light stabilizer, a known light stabilizer can be used, and among them, a hindered amine-based light stabilizer (HALS) is preferably mentioned.
Specific examples of the hindered amine-based photostabilizer include bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and methyl (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate. , 2,4-Bis [N-butyl-N- (1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl) amino] -6- (2-hydroxyethylamine) -1,3 , 5-Triazine, bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester and the like.
Examples of commercially available products of the hindered amine-based light stabilizer include TINUVIN 111FDL, TINUVIN123, TINUVIN 144, TINUVIN 152, TINUVIN 292, and TINUVIN 5100 manufactured by BASF.

The content ratio of the ultraviolet absorber is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 2 parts by weight, and 0. It is more preferably 1 to 1 part by weight.

<Inorganic particles>
As the inorganic particles, metal oxide particles are preferable.
As the metal oxide particles, metal oxide particles or composite metal oxide particles made of one or more metals selected from the group consisting of silicon, zirconium, titanium, antimony, tin, cerium, aluminum, zinc and indium are preferable. Can be mentioned.

The average particle size of the inorganic particles may be selected depending on the intended use, but is preferably 1 to 1,000 nm, more preferably 5 to 500 nm, and particularly preferably 10 to 100 nm. Within the above range, the transparency and appearance of the cured film are good.
In the present invention, the average particle size of the inorganic particles means the particle size when it is assumed that the particles are spherical particles from the specific surface area of the sample obtained by the BET method.

The inorganic particles may be surface-modified particles.
As the surface modifier, known ones can be used, and silane coupling agents, titanium coupling agents and the like are preferable.
Among them, a silane coupling agent is more preferable, and a compound having an ethylenically unsaturated group and an alkoxysilyl group is particularly preferable. In the above aspect, the hardness and curl resistance of the obtained cured film are excellent. Specific examples of the silane coupling agent include compounds similar to the compounds described below.
The amount of surface modification of the inorganic particles is not particularly limited, but the ratio of the surface modifier to the inorganic particles is 1.0 to 45.0% by weight based on the total weight of the surface modifier and the inorganic particles. It is preferable that the particles are reacted with.

The content ratio of the inorganic particles is preferably 25 to 400 parts by weight, more preferably 30 to 200 parts by weight, and 50 to 150 parts by weight with respect to 100 parts by weight of the total amount of the curable components. Is even more preferable. In the above aspect, the obtained cured film is excellent in adhesion, scratch resistance and curl resistance.

<Antioxidant>
The composition of the present invention may further contain an antioxidant for the purpose of improving the heat resistance and weather resistance of the cured film.
Examples of the antioxidant used in the present invention include a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and the like.
As the phenolic antioxidant, for example, hindered phenols such as dit-butylhydroxytoluene can be preferably mentioned. Examples of commercially available products include AO-20, AO-30, AO-40, AO-50, AO-60, AO-70, and AO-80 manufactured by ADEKA CORPORATION.
Preferred examples of the phosphorus-based antioxidant include phosphines such as trialkylphosphine and triarylphosphine, and trialkyl phosphite and triaryl phosphite. Commercially available products of these derivatives include, for example, ADEKA CORPORATION PEP-4C, PEP-8, PEP-24G, PEP-36, HP-10, 260, 522A, 329K, 1178, 1500, 135A, 3010. And so on.
Examples of the sulfur-based antioxidant include thioether-based compounds, and examples of commercially available products include AO-23, AO-412S, and AO-503A manufactured by ADEKA CORPORATION.

The content ratio of the antioxidant is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight, based on 100 parts by weight of the total amount of the composition of the present invention. In the above aspect, the stability of the composition is excellent.

<Surface modifier>
In the composition of the present invention, a surface modifier may be added for the purpose of enhancing the leveling property at the time of application, increasing the slipperiness of the cured film and enhancing the scratch resistance, and the like.
Examples of the surface modifier include a surface conditioner, a surfactant, a leveling agent, an antifoaming agent, a slipperiness-imparting agent, an antifouling agent, and the like, and these known surface modifiers can be used. ..
Among them, a silicone-based surface modifier and a fluorine-based surface modifier are preferably mentioned. Specific examples include a silicone polymer and oligomer having a silicone chain and a polyalkylene oxide chain, a silicone polymer and an oligomer having a silicone chain and a polyester chain, and a fluoropolymer having a perfluoroalkyl group and a polyalkylene oxide chain. And oligomers, as well as fluoropolymers and oligomers having a perfluoroalkyl ether chain and a polyalkylene oxide chain.
Further, a surface modifier having an oxetane ring or an oxylan ring in the molecule may be used for the purpose of enhancing the sustainability of slipperiness. The content ratio of the surface modifier is preferably 0.01 to 1.0 parts by weight with respect to 100 parts by weight of the total amount of the composition of the present invention. Within the above range, the surface smoothness of the cured film is excellent.

5. Method of use As a method of using the composition of the present invention, a conventional method may be followed.
For example, a method of applying the composition to the back surface coating layer of the mirror to be applied (hereinafter, also simply referred to as “base material”) by a usual coating method and then irradiating the active energy rays may be mentioned.
When the composition of the present invention is used under high humidity conditions, defects may occur in the cured film when the composition after application is insufficiently defoamed. For example, when the cured film obtained from the composition of the present invention is subjected to a hot water immersion test described later, defects may occur in the cured film if the defoaming of the composition after coating is insufficient. In order to solve this problem, it is preferable to heat at 40 to 60 ° C. for several minutes, preferably 1 to 30 minutes after application to defoam. However, the heating step is not essential because the amount of air bubbles contained in the applied composition differs depending on the coating method.
As the method of irradiating the active energy rays, a general method known as a conventional curing method may be adopted.
If necessary, it can be heated after being irradiated with active energy rays.

As the back surface coating layer of the mirror to which the composition of the present invention can be applied, it can be applied to a layer obtained from various backing paints.
The backing paint includes, for example, a thermosetting resin such as a melamine resin, an epoxy resin, an alkyd resin, and a phenol resin, a pigment, and a pigment dispersant, and if necessary, an organic solvent and the thermosetting resin. Examples thereof include paints in which a curing agent and other additives are dispersed.

The composition of the present invention can be suitably used for a melamine-containing layer, particularly as a back surface coating layer for a mirror.
The resin layer constituting the melamine-containing layer can be applied to various resins as long as it is a resin containing a melamine resin, and is formed from a paint obtained by mixing an alkyd resin, an epoxy resin, or a thermosetting acrylic resin with the melamine resin. The resin layer to be coated, and further, a melamine resin mixed with an alkyd resin, an epoxy resin, or a thermosetting acrylic resin, and further mixed with an additive usually used in a thermosetting paint, is formed by baking. Examples thereof include a resin layer to be formed. Examples of the additive include a paste dispersion stabilizer in which a pigment such as talc is dispersed, an antifoaming agent, and a leveling agent.

As the resin constituting the melamine-containing layer, an alkyd / melamine resin obtained from a mixture of a melamine resin and an alkyd resin is preferable.
As the melamine resin, methylol melamine obtained by condensing melamine and formaldehyde under alkaline conditions can be preferably used, and any melamine resin can be used.
Commercially available products can be used as the melamine resin, and as the methylated melamine resin, MW-30MLF, MW-30M, MW-30LF, MW-30, MW-22, MS-11 manufactured by Sanwa Chemical Co., Ltd. , MW-12LF, MS-001, MZ-351, MX-730, MX-750, MX-706, MX-035, etc., DIC Co., Ltd. Amidia L-105-60, etc. Amidia J-820-60, L-109-65, L-117-60, L-125-60, L-127-60, L-150-60, L-16-60B manufactured by DIC Co., Ltd. Examples of the mixed etherified melamine resin include MX-45 and MX-410 manufactured by Sanwa Chemical Co., Ltd., and examples of the trimethylol melamine resin include Riken Resin MA-156 and MM- manufactured by Miki Riken Kogyo Co., Ltd. Examples thereof include 3C and MM-35.
Commercially available products can be used as the alkyd resin, and as the long oil alkyd resin made from soybean oil, flaxseed oil and the like, DIC Corporation's alkydia 52-514, EL-8001, EL-8011, etc. Examples of the medium oil alkyd resin include KE-183, etc., and examples of the medium oil alkyd resin include Alkydia 1334-EL, 16-141, EL-4501-50, ES-4505-60X, ES-5103-50X, WJB-27, manufactured by DIC Corporation. Examples thereof include ES-4012 and the like, and examples of the phenol-modified alkyd resin include Alkydia M-2167-50, M-2168-50, M-2171-50, M-2174-50, P-539 and the like manufactured by DIC Corporation. Examples of other various solvent-based polyester resins include Beckolite 46-118, 46-119, 54-707, M-6205-50, and M-6402-50 manufactured by DIC Corporation.
As the melamine resin and the alkyd resin, only one type or a plurality of types may be used, respectively, and a mixture thereof may be used. Various commercially available products other than those listed above can be used.

The method for applying the composition of the present invention to the substrate may be appropriately set according to the intended purpose, and is a bar coater, an applicator, a doctor blade, a dip coater, a roll coater, a spin coater, a flow coater, a knife coater, and a comma. Examples thereof include a method of coating with a coater, a reverse roll coater, a die coater, a lip coater, a spray coater, a gravure coater, a micro gravure coater and the like.

The film thickness of the composition cured film with respect to the substrate may be appropriately set according to the purpose. The thickness of the cured film may be selected depending on the use of the substrate to be used and the application of the manufactured substrate having the cured film, but is preferably 10 to 500 μm, more preferably 20 to 100 μm. ..

When the composition contains an organic solvent, it is preferable to apply it to the substrate and then heat and dry it to evaporate the organic solvent.
The drying temperature is not particularly limited as long as the applied base material is at a temperature or lower that does not cause problems such as deformation. The preferred heating temperature is 40 to 100 ° C. The drying time may be appropriately set depending on the substrate to be applied and the heating temperature, and is preferably 0.5 to 3 minutes.

Examples of the active energy ray for curing the composition of the present invention include electron beam, ultraviolet light and visible light, but ultraviolet light or visible light is preferable, and ultraviolet light is particularly preferable. Examples of the ultraviolet irradiation device include a high-pressure mercury lamp, a metal halide lamp, an ultraviolet (UV) electrodeless lamp, and a light emitting diode (LED).
The irradiation energy should be appropriately set according to the type and composition of the active energy rays. For example, when a high-pressure mercury lamp is used, the irradiation energy in the UV-A region is 100 to 8,000 mJ /. cm ² is preferable, and 200 to 3,000 mJ / cm ² is more preferable.

Immediately after irradiation with active energy rays, tack may remain on the cured film, but even in this case, it is completely cured by leaving it at room temperature for about 10 minutes or more.
When coating and curing are continuously performed using a device equipped with a conveyor, post-curing by heating in a drying furnace may be performed after irradiation with active energy rays. Although there is no limitation on the temperature, it is preferable to heat at 40 to 80 ° C. for about 1 to 30 minutes.

6. Applications The composition of the present invention can be used for various mirrors, has excellent adhesion to the back surface paint layer of the mirror, particularly a melamine-containing layer, and has excellent water resistance and acid resistance, and is mainly used around water. It can be preferably used as a protective coating agent for the back surface paint layer of mirrors used in kitchens and bathrooms.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples.
Further, in the following, unless otherwise specified, "part" means a part by weight, and "%" means% by weight.

1. 1. Examples 1 to 5 and Comparative Examples 1 to 2 (preparation of composition)
Each component shown in Table 1 below was stirred and mixed at 30 ° C. to obtain the compositions of Examples 1 to 5 and Comparative Examples 1 and 2.
The viscosity of the obtained composition was measured at 25 ° C. with an E-type viscometer. The results are shown in Table 1.

2. 2. Evaluation of the Backside Paint Layer (Alkyd / Melamine Paint Layer) of the Mirror The obtained compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were cut using a bar coater, and glass KF-manufactured by LIXIL Co., Ltd. 3045A (having alkyd melamine as the back surface paint layer) (356 mm × 305 mm × 5 mm) The back surface was coated with a film thickness of 50 μm to prepare a test piece.
Next, using a high-pressure mercury lamp equipped with a conveyor [H06-L 41 manufactured by Eye Graphics Co., Ltd.], ultraviolet rays were applied to the test piece under the conditions of UV-A illuminance of 80 W / cm and irradiation energy of 1,000 mJ / cm ² . Irradiated.
The obtained cured film was allowed to stand at room temperature and 40% RH for 24 hours, and the adhesion and the appearance of the cured film were evaluated according to the following method. The results are shown in Table 3.

1) Adhesion As a test piece for evaluation of adhesion, the cured film obtained above is a) cured 24 hours later, b) immersed in a 10% hydrochloric acid aqueous solution for 48 hours, then taken out and washed with tap water. After that, three kinds of test specimens, one dried indoors for 24 hours and c) soaked in warm water at 60 ° C. for 7 days and dried indoors for 24 hours, were used.
Cuts in the cured film of the three types of specimens at intervals of 1 mm in length and width with a cutter knife to form 100 squares with a size of 1 mm x 1 mm, and on this grid, # 405 cellophane manufactured by Nichiban Co., Ltd. After applying the tape, it was strongly peeled off. The number of residual films after exfoliation was evaluated. The larger the number of residual films, the better the adhesion.

2) Appearance of the cured film The appearance of the same three types of test specimens as those used in the adhesion test was visually confirmed and evaluated according to the following three levels.
◎: Transparent with a smooth cured film without unevenness, 〇: Smooth cured film with no unevenness, but slightly cloudy, ×: Clearly dented or bulged

The abbreviations in Tables 1 and 2 mean the following. The parentheses in Tables 1 and 2 mean the number of copies of each component.
(A) Ingredient
OXT-101: 3-Ethyl-3-hydroxymethyloxetane [Aronoxetane OXT-101 manufactured by Toagosei Co., Ltd.]
OXT-221: 3-Ethyl3 {[(3-Ethyloxetane-3-yl) methoxy] Methyl} Oxetane [Aron Oxetane OXT-221 manufactured by Toagosei Co., Ltd.]
(B) Ingredient
-JER-828: Bisphenol A type epoxy resin [jER-828 manufactured by Mitsubishi Chemical Corporation]
(C) Ingredient
-CPI-100P: 50% propylene carbonate solution of triarylsulfonium / PF ₆ salt [CPI-100P manufactured by San-Apro Co., Ltd.]

3. 3. Evaluation Results As is clear from the results of Examples 1 to 5 in Table 3, the composition of the present invention was excellent in adhesion to the back surface coating layer of the mirror, acid resistance and water resistance.
On the other hand, in the composition of Comparative Example 1, the adhesion was slightly lowered after the immersion in hydrochloric acid, the adhesion could not be obtained after the immersion in warm water, and the appearance was poor. Further, the composition of Comparative Example 2 has insufficient initial adhesion, and after immersion in hydrochloric acid, the adhesion is greatly reduced and the appearance is poor, and after immersion in warm water, adhesion is not obtained and the appearance is poor. rice field.

In the active energy ray-hard coating agent composition for the back surface coating layer of the mirror of the present invention, the obtained cured film has adhesion, water resistance, and adhesion to the back surface coating layer of the mirror, particularly to the melamine-containing layer. It has excellent acid resistance and can be preferably used as an anti-contact coating agent on the back surface of mirrors mainly used around water.

Claims (10)

An active energy ray-curable coating agent composition for a back surface coating layer of a mirror containing the following components (A), (B) and (C).
(A) Component: Compound having an oxetane ring (B) Component: Compound having an oxylan ring (C) Component: Compound that initiates cationic polymerization by irradiation with active energy rays The back surface coating layer of the mirror according to claim 1, wherein the component (A) contains a component (A1): a compound having one oxetane ring and / and a component (A2): a compound having two or more oxetane rings. Active energy ray-curable coating agent composition for use. The active energy ray-curable coating agent composition for a back surface coating layer of a mirror according to claim 1 or 2, wherein the component (A1) contains a compound having one oxetane ring and one hydroxyl group. The active energy ray-curable coating agent composition for a back surface coating layer of a mirror according to claim 1 or 2, wherein the component (A2) contains a compound having two oxetane rings. The active energy ray-curable coating for the back surface coating layer of the mirror according to any one of claims 1 to 3, wherein the component (B) contains a component (B1): a compound having two or more oxylan rings. Agent composition. The active energy ray-curable coating agent composition for a back surface coating layer of a mirror according to any one of claims 1 to 5, wherein the component (B1) contains an aromatic epoxy compound. The active energy ray-curable coating agent composition for a back surface coating layer of a mirror according to claim 6, wherein the component (B1) is an aromatic epoxy compound having a bisphenol skeleton. Claims 1 to 7 include 5 to 95% by weight of the component (A) and 95 to 5% by weight of the component (B) in a total of 100% by weight of the component (A) and the component (B). The active energy ray-curable coating agent composition for the back surface coating layer of the mirror according to any one of the above items. The active energy ray-curable coating agent composition for the back surface paint layer of a mirror according to any one of claims 1 to 8, wherein the back surface paint layer of the mirror contains a melamine-containing layer. The active energy ray-curable coating agent composition for a back surface coating layer of a mirror according to claim 9, wherein the melamine-containing layer contains an alkyd melamine resin.