JPH0330616B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high-energy ray-curable resin composition that can be easily cured by irradiation with high-energy rays and can form a coating film having excellent adhesion to substrates such as metals, glass, and plastics. Conventionally known high-energy ray-curable resin compositions include unsaturated polyester resins, acrylate-based resin compositions such as epoxy acrylate, epoxy methacrylate, acrylate, and methacrylate, and methacrylate-based resin compositions.
However, they have very poor adhesion to base materials such as metal, glass, and plastic, and their field of application is narrowly limited. Recently, patent applications have been filed by General Electric Company and others regarding photopolymerization catalysts for cationically polymerizable compounds such as epoxy resins (Japanese Patent Application Laid-Open No.
-151996, JP-A-151997, etc.). Generally, epoxy resins have good adhesion to substrates. However, although the cured coating film of UV-curable epoxy resin compositions has better adhesion to the substrate than conventional acrylate-based UV-curable resins, it is hard to cure because the resin composition is cured within seconds by UV irradiation. The internal stress of the composition is large, and therefore it is inferior in terms of adhesion to substrates, especially metals, compared to ordinary thermosetting epoxy resin compositions. Usually, a method for improving adhesion is to mix a rubber component such as butyral rubber, chloroprene rubber, neoprene rubber, butadiene rubber, natural rubber, or a thermoplastic polymer into the composition. However, according to these methods, the cured product may have poor surface hardness, solvent resistance, etc., and depending on the compound mixed, the composition may have poor ultraviolet curability. Generally, in order to improve the adhesion of acrylate-based ultraviolet curable resin compositions, for example,

An acrylate monomer having a phosphoric acid group such as [formula] may be added to the composition, but when the acrylate monomer is mixed with an epoxy resin, the phosphoric acid group of the acrylate monomer and the oxirane ring of the epoxy resin are The reaction causes gelation, making it unsuitable for practical use. In view of the above-mentioned circumstances, the present inventors continued their studies with the aim of developing a high-energy ray-curable resin composition that has excellent high-energy ray curability and excellent adhesion to the substrate of the cured product. One or more cationic polymerizable compounds whose main component is an epoxy resin having two or more oxirane rings in one molecule, and the cationic polymerizable compound polymerizes when exposed to high energy rays as component B. 0.5 to 10% (wt%,
The same applies hereinafter) in an effective amount of a photoinitiator, 0.1 to 30% amount of 1 as component C to the cationic polymerizable compound.
General formula (): (In the formula, R, R ¹ and R ² represent an aliphatic organic group or an aromatic organic group, and at least one of R, R ¹ and R ² represents an organic group having an acryloyl group or a methacryloyl group. ) and a resin composition consisting of a radical photosensitizer in an amount of 0.1 to 10% based on the cationic polymerizable compound as component D, which has excellent curability by high energy ray irradiation, The present inventors have discovered that the resulting cured product exhibits excellent adhesion to glass and plastics, particularly metals, without deteriorating its surface hardness or solvent resistance, leading to the completion of the present invention. That is, in the present invention, a photoinitiator is used as component B, and D
One or more cationic polymerizable compounds whose main component is an epoxy resin having two or more oxirane rings in one molecule, which is component A, to which an effective amount of a radical photosensitizer is added as a component, are combined with the general formula ( ), for example, When a high-energy ray-curable resin composition was prepared by adding component C, which is an acrylate monomer in which a phosphoric acid group is protected with another organic group, the cured product obtained from the composition was found to be suitable for glass, plastic, etc. In particular, it exhibits excellent adhesion to substrates such as metals, and other properties such as surface hardness and solvent resistance of the cured product do not deteriorate, and it does not cause gelation. We have come to solve the various shortcomings of . The cationic polymerizable compound of component A used in the present invention is mainly composed of an epoxy resin having two or more oxirane rings in one molecule. As the epoxy resin, bisphenol A type epoxy resin, novolak type epoxy resin, alicyclic epoxy resin, etc. are preferable. The bisphenol A type epoxy resins include Epicote 828, Epicote 834, Epicote
836, Epicote 1001, Epicote 1004, Epicote 1007, (trade names, manufactured by Ciel Chemical Co., Ltd.),
DER331, DER332, DER661, DER664,
DER667 (manufactured by Dow Chemical Company, product name), Araldite 260, Araldite 280, Araldite
Examples include Araldite 6071, Araldite 6084, and Araldite 6097 (trade names, manufactured by Ciba Geigy), and these may be used alone or as a mixture. The novolac type epoxy resins include Epicote 152 and Epicote 154 (all manufactured by Ciel Chemical Co., Ltd.,
Product name), Araldite EPN1138, Araldite
EPN1139, Araldite ECN1235, Araldite ECN1273, Araldite ECN1280, Araldite ECN1299 (trade name, manufactured by Ciba Geigy), DEN431, DEN438 (trade name, manufactured by Dow Chemical), etc., and these may be used alone or in combination. It will be done. The alicyclic epoxy resin is Araldite.
CY175, Araldite CY177, Araldite
CY179, Araldite CY184, Araldite
Examples include CY192 (trade name, manufactured by Ciba Geigy). Other butadiene-based epoxy resins can also be used, and mixtures of the various epoxy resins mentioned above can also be used. Furthermore, a monofunctional epoxy diluent or an acid anhydride curing agent may be used within a range that does not deteriorate the curing properties. Examples of the monofunctional epoxy diluent include phenyl glycidyl ether and t-butyl glycidyl ether. The acid anhydride curing agents include pyromellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride,
Examples include methyltetrahydrophthalic anhydride. Furthermore, it is also possible to use a cationically polymerizable vinyl compound mixed with the epoxy resin. Examples of the cationically polymerizable vinyl compound include styrene, allylbenzene, vinyl ether, N-vinylcarbazole, and N-vinylpyrrolidone. As the photoinitiator used in the present invention, which releases a Lewis acid catalyst capable of polymerizing the cationically polymerizable compound when exposed to high-energy rays as the B component, Japanese Patent Application Laid-open No. 151996/1989 and Japanese Patent Application Publication No. 151996, Showa 50-151997
Aromatic halonium salts, group a elements or photosensitive aromatic onium salts of group a elements, etc., which are disclosed in Japanese Patent Publication No. 1, etc., may be used. The aromatic halonium salt has the general formula (): [(R) _a (R ¹ ) _b X] _c ⁺ [MQ _d ]-(de-e) () (wherein, R is a monovalent aromatic organic group, R ¹ is a divalent aromatic organic group, X is a halogen atom such as I, Br, Cl, M is a metal or metalloid, Q is a halogen atom such as Cl, F, Br, I, a is 0 or 2, b is 0 or 1, the sum of a and b is equal to 2 or the valence of X, c is equal to (de), e is 2 to 7, and (equivalent to the valence of M, and d is an integer of 8 or less that is larger than e). Examples of the halonium salt represented by the general formula () include:

【formula】

【formula】

【Formula】 etc. The group a element or the photosensitive aromatic onium salt of the group a element has the following general formula (): [(R) _a (R ¹ ) _d (R ² ) _c Y] _d ⁺ [MQ _e ] ^{-( ef)} () (wherein R is a monovalent aromatic organic group, R ¹ is a monovalent aliphatic organic group selected from the group consisting of an alkyl group, a cycloalkyl group, and a substituted alkyl group, R ²
is a heterocyclic group selected from an aliphatic organic group and an aromatic organic group or a polyvalent organic group constituting a condensed ring structure, Y is a group a element of S, Se, Te or N,
A group a element selected from P, As, Sb and Bi, M is a metal or metalloid, Q represents a halogen atom, a is an integer of 0 to 4, b is an integer of 0 to 2,
c is an integer from 0 to 2, and the sum of a, b, and c is equal to the valence of Y, 3 when Y is a group a element, and 4 when Y is a group a element. is equal to
d=e−f, f is 2 to 7 and equal to the valence of M, and e is an integer greater than f and 8 or less). As an onium salt of a group a element represented by the above general formula (),

【formula】

【formula】

【formula】

【formula】

etc., and the a-th represented by the general formula ()
As onium salts of group elements,

【formula】

【formula】

etc. can be mentioned. When the B component is mixed with the A component and the mixture is exposed to high energy rays, the B component releases a Lewis acid, and the Lewis acid accelerates the polymerization of the A component, thereby curing the A component. . The effective amount of component B added to component A is 0.5 to 10%, preferably 1 to 5%, based on the amount of component A.
If it is less than 0.5%, the curing speed due to high-energy ray irradiation will be slow, and if it exceeds 10%, the manufacturing cost of the resin composition will be high. The phosphoric acid derivative used in the present invention that improves the adhesion of component C to the base material (especially metal) has the general formula (): (In the formula, R, R ¹ and R ² represent an aliphatic organic group or an aromatic organic group, and at least one of R, R ¹ and R ² represents an organic group having an acryloyl group or a methacryloyl group. ) is used. Examples of the compound represented by the general formula () include: etc. Furthermore, addition of these C components to a high-energy radiation-curable epoxy resin also leads to imparting flame retardancy to the epoxy resin. One method of protecting the phosphoric acid group in the C component with another organic group is to protect compounds having one oxirane ring in the molecule, such as glycidyl methacrylate, phenyl glycidyl ether, t-butyl glycidyl ether, epichlorohydrin, etc. The method of reacting a molecule with a phosphoric acid group and introducing an organic group as a protective group for the phosphoric acid group is simple and effective, and has good compatibility with epoxy resins. The effective amount of component C added to component A is 0.1 to 30%, preferably 0.5 to 10%, based on the amount of component A.
If it is less than 0.5%, there is little effect on improving adhesion, and if it exceeds 10%, the photolysis efficiency of component B tends to decrease. As the radical photosensitizer of component D used in the present invention, benzophenone, benzoin, thioxanthone, anthraquinone, acetophenone, and derivatives thereof can be used. The D component must have the property of polymerizing the phosphoric acid derivative, which is the C component, without reducing the photolysis efficiency of the B component. The effective amount of component D added to component A is 0.1 to 10%, preferably 0.5 to 5%, based on the amount of component A.
If it is less than 0.5%, the speed of polymerizing component C will be slow;
If it exceeds 5%, it tends to have an adverse effect on the photolysis efficiency of component B. Although the composition according to the present invention is based on an epoxy resin, it is also possible to add conventional acrylate compounds as desired within a range that does not deteriorate the properties of the cured coating film obtained from the composition. . Examples of the acrylate compounds include epoxy acrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and diethylene glycol diacrylate. Ultraviolet rays are the most efficient among the high-energy rays to be irradiated for curing the composition of the present invention. Light sources for this purpose include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, and carbon arc lamps. In addition, curing by electron beam irradiation or the like may also be used. In addition, the composition of the present invention may contain inorganic fillers, pigments, dyes, etc. within a range that does not deteriorate the high-energy ray curability of the composition and the surface hardness, solvent resistance, etc. of the cured coating film obtained from the composition. , a spreading agent, a viscosity modifier, etc. The composition of the present invention is used to improve the curing properties of paints and coatings based on epoxy compounds by mixing them with paints and coatings based on epoxy compounds, and the resulting cured product can be used for metals, wood, paper, glass, It forms a coating film with excellent adhesion to substrates such as ceramics and plastics, which protects the product and is useful for decoration. Furthermore, when mixed with printing ink or marking ink, the curing properties of the ink are improved, which helps shorten the drying time of the ink and improve adhesion. The composition of the present invention will be described in detail below based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. Example 1 Bisphenol A type epoxy resin Epicoat
2 parts of 4,4'-dimethyldiphenyliodonium hexakifluorophosphate, 0.3 parts of anthraquinone, and 2.0 parts of diethyl ethyl methacrylate phosphate were added to 100 parts of 828 to prepare a high-energy radiation-curable resin composition. The composition is coated on various substrates using a bar coater.
The composition was coated to a thickness of 50 μm and irradiated with ultraviolet light using a 2.5 KW high-pressure mercury lamp (product name H25-UVA) manufactured by Mitsubishi Electric Corporation as a light source at an irradiation distance of 15 cm and a moving speed of 4 m/min. The pencil hardness of the cured product, the adhesion to aluminum plates, zinc phosphate treated copper plates, glass plates, and polyester films by making a cross cut in the cured product and peeling it off with Sellotape, and the surface of the cured product using absorbent cotton impregnated with Ascent. The solvent resistance was measured and tested by rubbing for 5 seconds and the results are shown in Table 1. The ultraviolet irradiation time is expressed by the number of irradiations under the above conditions, and the time for one irradiation was about 0.75 seconds. Regarding the adhesion test, those with no peeling of the paint film are marked as 〇, those with partial peeling of the paint film are marked with △, and those with complete peeling are marked as ×. Regarding the solvent resistance test, those with no effect are marked as 〇 and those with no effect on the surface area. Those with only a slight change in appearance were rated △, and those that dissolved were rated ×. Example 2 Bisphenol A type epoxy resin Epicoat
A composition was prepared by adding 2 parts of triphenylphonium hexafluorophosphate, 0.5 parts of diisopropylthioxanthone, and 5 parts of an equivalent adduct of phosphoric acid monoethyl acrylate and phenyl glycidyl ether to 100 parts of 828. A sample was prepared in the same manner, the sample was irradiated with ultraviolet rays, and the properties of the obtained cured product were measured and examined in the same manner as in Example 1. The results are shown in Table 1. Example 3 Composition in which 2 parts of 4,4'-diphenyliodonium tetrafluoroborate, 0.5 part of thioxanthone, and 1 part of an equivalent adduct of phosphoric acid monoethyl acrylate and phenyl glycidyl ether were added to 100 parts of novolac type epoxy resin DEN431. A sample was prepared in the same manner as in Example 1, the sample was irradiated with ultraviolet rays, the properties of the obtained cured product were measured and inspected in the same manner as in Example 1, and the results are shown in Table 1. Comparative Examples 1 to 3 Comparative Examples 1 to 3 Comparative Examples 1 to 3 were prepared by removing the radical photoinitiator and phosphoric acid derivative from the resin compositions corresponding to Examples 1 to 3, and these were designated as Comparative Examples 1 to 3, respectively. A sample was prepared using the composition in the same manner as above, the sample was irradiated with ultraviolet rays, and the properties of the obtained cured product were measured and inspected in the same manner as in Example 1, and the results are shown in Table 1. Ta. Comparative example 4 Bisphenol A type epoxy resin Epicoat
Example 1 A composition was prepared by adding 2 parts of 4,4'-dimethylphenyliodonium hexafluorophosphate and 15 parts of butyral resin (manufactured by Denki Kagaku Co., Ltd., trade name 2000-L) to 100 parts of 828. A sample was prepared using the composition in the same manner as above, and the sample was cured by ultraviolet rays.The properties of the obtained cured product were measured in the same manner as in Example 1, and the results are shown in Table 1.

【table】

Claims (1)

[Scope of Claims] 1 (A) One or more cationic polymerizable compounds whose main component is an epoxy resin having two or more oxirane rings in one molecule (B) When exposed to high energy radiation, the cations A photoinitiator (C) in an effective amount of 0.5 to 10% by weight, based on the cationic polymerizable compound, capable of liberating a Lewis acid catalyst capable of polymerizing the polymerizable compound; ．． General formula () with an amount of 1 to 30% by weight: (In the formula, R, R ¹ and R ² represent an aliphatic organic group or an aromatic organic group, and at least one of R, R ¹ and R ² represents an organic group having an acryloyl group or a methacryloyl group. ) A high-energy beam-curable resin composition comprising a radical photosensitizer in an amount of 0.1 to 10% by weight based on the cationically polymerizable compound (D). 2 The photoinitiator is an aromatic halonium salt,
The resin composition according to claim 1, which is one or a mixture of two or more of photosensitive aromatic onium salts of group elements or group a elements. 3 The radical photosensitizer is benzophenone,
benzoin, thioxanthone, anthraquinone,
The resin composition according to claim 1, which is one or a mixture of two or more selected from the group consisting of acetophenone and derivatives thereof.