JPH1060026A - Energy beam-curable composition and cured product therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition containing a specific onium salt as photopolymerization initiator, excellent in curability even in the case of being incorporated with pigment among others. SOLUTION: This energy beam-curable composition comprises (A) a cationically polymerizable compound, (B) a radically polymerizable compound, (C) a photopolymerization initiator, an onium salt with the maximum molar extinction coefficient at a wavelength of 360nm or longer of >=100 (pref. an onium salt having thiochitosan structure; specifically, an onium salt of e.g. the formula), and optionally, (D) a pigment. It is preferable that the total amount of the components A and B is 34.7-99.7wt.% based on the composition and the components C and D are 0.3-15wt.% and 0-70wt.%, based on the composition, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a compound having an ability to initiate cationic polymerization and an ability to initiate radical polymerization by itself and having a wavelength of 360.
The present invention relates to an energy ray-curable composition excellent in curability, particularly a composition containing a photopolymerization initiator which is an onium salt having a maximum molar extinction coefficient of 100 nm or more and having a maximum molar extinction coefficient of 100 or more, and a cured product thereof.

[0002]

2. Description of the Related Art Photopolymerizable compositions include printing inks, paints,
In the fields of coatings, liquid resist inks, adhesives, and the like, researches have been actively conducted from the demands of energy saving, space saving, and non-polluting properties, and practical application has been studied. These studies are based on radical polymerization of double bonds,
It was based on a cationically polymerizable substance, for example, a cationic polymerization reaction of an epoxy resin. When a radical polymerizable substance and a cationic polymerizable substance are used in combination, it is common to use two kinds of photoradical polymerization initiators and photocationic polymerization initiators in combination.

[0003]

In order to cure an epoxy resin by light, for example, US Pat. No. 3,794,576 discloses a method in which a photosensitive aromatic diazonium salt is used as a photopolymerization initiator and the photopolymerization initiator is irradiated with light. A method of polymerizing an epoxy resin by decomposing and releasing a Lewis acid has been proposed. However, the aromatic diazonium salt releases nitrogen gas at the same time as the Lewis acid by photolysis, so that when the film thickness of the epoxy resin is 15 μm or more, the coating film foams and is not suitable for thick coating. Furthermore, the mixture with the epoxy resin has a problem in storage stability such that curing gradually proceeds even when no light is present, and cannot be said to be a one-part composition. In order to overcome the drawbacks of the above diazonium salt-based initiator, various studies have been made, and aromatic sulfonium salt-based or aromatic iodonium salt-based initiators and the like containing them as techniques for improving thick coating properties and storage stability The curable resin composition is disclosed in JP-B-52-14278, JP-B-52-14278.
-14277, JP-A-54-53181,
JP-B-59-19581 and JP-A-56-554.
No. 20, for example. However, the curability of the colored composition is insufficient, and no improvement has been proposed. When a radically polymerizable substance and a cationically polymerizable substance are used together, two kinds of photoradical polymerization initiators and cationic photopolymerization initiators must be used in combination.
Also, as the field of use of photopolymerizable compositions expands, it is important to provide new compositions in order to meet market demands.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have started photopolymerization of a specific onium salt in a composition using both a radical polymerizable substance and a cationic polymerizable substance. By containing it as an agent, the present invention succeeded in providing an energy ray-curable composition and a cured product which are excellent in curability, particularly excellent in curability even in a composition containing a pigment. That is, the present invention provides (1) a cationically polymerizable substance (A) and a radically polymerizable substance (B), and an onium salt having a wavelength of 360 nm or more and 600 nm or less (preferably 500 nm or less) and a maximum molar extinction coefficient of 100 or more. An energy ray-curable composition containing a photopolymerization initiator (C) and a pigment (D) as an optional component.

(2) The photopolymerization initiator (C) described in (1)
Is an onium salt having a thioxanthone structure, and (3) a cured product of the composition described in (1) or (2).

In the practice of the present invention, preferred examples of the cationically polymerizable substance (A) include, for example, the following three different epoxy resins which can be cured at ordinary ambient temperature, and those belonging to the first group include the following. Consists of epoxy ethers having the structural formula

[0007]

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(Wherein n is a number from 1 to 3;
Is an aliphatic and alicyclic group having 5 to 12 carbon atoms. ) The second group is a structural formula

[0009]

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And epoxy carbocyclic ethers having the formula: Here, R ¹ may be mononuclear or polynuclear, but is an epoxidized carbocyclic group having 4 to 12 carbon atoms in its ring structure. R ² is a C ₁ -C ₃ alkyl group, R ³ is R ¹
Or an epoxy group having the following general structural formula.

[0011]

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However, R ⁴ may be a hydrogen atom, a C ₁ -C ₃ alkyl group or a phenyl group. Further, such an alkyl group or a phenyl group may or may not have a substituent. a = 0 or 1, and n = 1 to 3. A third group includes epoxy esters having at least two epoxidized cyclic alkyl groups.

Vinyl type compounds, for example, vinyl type aromatic hydrocarbons such as styrene, isobutyl ether, n
-Octyl vinyl ether, 2-hydroxyethyl vinyl ether, 2-chloroethyl vinyl ether, cyclohexyl-1,4-dimethylol monovinyl ether,
Triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tricyclodecane dimethylol divinyl ether, polyurethane polyvinyl ethers, polyester polyvinyl ethers, phenol
Vinyl ethers such as novolak polyvinyl ethers; acrolein; vinylallenes such as 1-vinylpyrene and acenaphthalene; vinyl alicyclic compounds such as vinylcyclohexane; conjugated gens such as isobutylene, butadiene and isoprene. It is. Further, oxetanes and oxolanes (eg, tetrahydrofuran and trioxane) can also be used. Other classes of compounds include beta-lactones, for example, cyclic esters such as propiolactone, and cyclic amines such as 1,3,3-trimethylazetidine. Yet another type of cationically polymerizable material includes a cyclic organosilicon compound such as hexamethyltrisiloxane. Still another class of cationically polymerizable materials that can be used include Crivello U.S. Pat. No. 410, July 15, 1978.
Thermosetting aldehyde condensed organic resins such as urea / formaldehyde resin, phenol / formaldehyde resin, and melamine / formaldehyde resin described in US Pat.

[0014] Cationic polymerizable materials suitable for the practice of the present invention are described in Pappas, "UVCURING; SCIENCE A.
ND TECHNOLOGY ”(Stamford Technology Marketing Corporation, Connecticut); Criv
ello U.S. Patent Nos. 4,150,988; 4,102,687.
No. 4069056. The cationically polymerizable substance (A) is based on at least an epoxy resin, and these are at least one functional epoxy group or at least one such that they can be polymerized by opening the oxirane ring so that they can be polymerized by opening the oxirane ring. It is a monomeric or oligomeric substance having a functional epoxy group or oxirane ring. Furthermore, the use of polymeric epoxy compounds is permissible if they can be dispersed in the composition and furthermore can be polymerized or crosslinked to give a strong polymer. The epoxy compound may be aliphatic, alicyclic, aromatic or heterocyclic.

As the polymerizable epoxy compound, an epoxy resin will be used alone or in combination.
They also have an average epoxy equivalent of about 50-500.
It will take a value of zero. The carbon chain having an epoxy group may have other substituents such as ethers, esters, halogens, and phosphates, and these compounds are acrylates, silicons and the like. It may have another polymerizable functional group.

Typical epoxy compounds are commercially available, and the most well-known ones are bisphenol A and epichlorohydrin reactant, phenol novolak, cresol novolak and epichlorohydrin reaction, and aliphatic glycidyl ether compounds. , 3,4-
Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, vinylcyclohexene dioxide, 2- [3,4-epoxycyclohexyl-
5,5-subiro-3,4-epoxy] cyclohexanemetadioxane, alicyclic epoxy compounds such as 1,2-epoxy-p-vinylcyclohexene, and the like.

Specific examples of the radical polymerizable substance (B) include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Hydroxybutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethyl-hexylpolyethoxy (meth) acrylate, carbitol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine, N-vinylcaprolactam , Dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, hydrogenated dicyclopentenyl (meth) acrylate,
Isobornyl (meth) acrylate, cyclohexane-
1,4-dimethylol mono (meth) acrylate, o-
Phenyloxyethyl (meth) acrylate, o-phenylphenyloxyethyloxyethyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tribromophenyloxyethyl (meth) acrylate, 1,6-hexanediol di (meth) Acrylate, neopentyl glycol di (meth) acrylate,
1,9-nonanediol di (meth) acrylate, neopentyl glycol polypropoxy-di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxypivalate, bisphenol A polyethoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) Acrylate, polyethylene glycol di (meth) acrylate, 2,4-bis (acryloxyethyl) -6-ethanol isocyanurate, trimethylolpropane tri (meth) acrylate, trimethyloloctane tri (meth) acrylate, trimethylolpropane polyethoxy Tri (meth) acrylate, trimethylolpropane, polypropoxytri (meth) acrylate, tris (acryloxyethyl) isocyanurate, pentae Suritorutori (meth) acrylate, pentaerythritol polyethoxy tetra (meth)
Reaction of acrylate, pentaerythritol polypropoxytetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Sex monomer,

Bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, trisphenol methane epoxy resin, biphenyl epoxy resin, aliphatic glycidyl ether, alicyclic Epoxy (meth) acrylates, which are reaction products of an epoxy resin such as a formula epoxy resin and an unsaturated group-containing compound having one carboxylic acid in a molecule such as a (meth) acrylic acid (meth) acrylic acid dimer, (Meta)
Acrylate polyhydrochloric anhydride reactant,

Ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol,
1,6-hexanediol, 1,4-butanediol,
Polyol (a) such as polytetramethylene glycol, polybutadiene diol, bisphenol A polyethoxy diol, and trimethylolpropane, polyol (a) and polybasic acid (for example, maleic acid, succinic acid, adipic acid, phthalic acid, terephthalic acid, Isophthalic acid, tetrahydrophthalic acid, hexasdrophthalic acid, methyl
Polyesterpolyol (a-1), which is a reaction product with tetrahydrophthalic acid or an acid anhydride thereof, polyol (a) and ε-caprolactone, or polyol (a) and the above-mentioned polybasic acid or acid anhydride thereof. Polycaprolactone polyol (a-2) which is a reaction product with ε-caprolactone, polycarbonate polyol (a-
3) and organic polyisocyanates (eg, tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, bis (4-
Isocyanate phenyl) methylene, xylylene diisocyanate, hexamethylene diisocyanate trimer, etc.) and hydroxyl group-containing (meth) acrylates (for example, 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, etc. A urethane (meth) acrylate which is a reaction product of an organic polyisocyanate and the above-mentioned hydroxyl group-containing (meth) acrylate,

The above-mentioned polyester polyol (a-1)
Oligomers such as (meth) acrylic acid ester, unsaturated polyester silicon (meth) acrylate and polybutadiene poly (meth) acrylate.

In the present invention, a photopolymerization initiator (C) which is an onium salt having a wavelength of 360 nm or more and a maximum molar extinction coefficient of 100 or more and having both photoradical polymerization initiation ability and photocationic polymerization initiation ability is used. Specific examples of the photopolymerization initiator (C) include, for example,

[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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An onium salt which is a sulfonium salt having a thioxanthone structure, such as

[0033]

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[0034]

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[0035]

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[0036]

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Onium salts which are sulfonium salts having an anthraquinone structure, such as

[0038]

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[0039]

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And onium salts which are sulfonium salts having an acridone structure. Particularly preferred onium salts in the present invention include:

[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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Onium salts, which are sulfonium salts having a thioxanthone structure, can be mentioned. These onium salts are quite sensitive to ultraviolet radiation of wavelengths not absorbed by the pigment and have a wavelength of 360
In the case where there is no absorption at nm or more and the molar extinction coefficient is 100 or less, curing does not occur or curing is slow, which is problematic. The maximum cationic extinction coefficient at 360 nm or more of the cationic photopolymerization initiator (C) used in the present invention is 100 or more, preferably 1,000 or more, and particularly preferably 2,000 or more.

In the present invention, a pigment (D) is used as an optional component. Specific examples of the pigment (C) include, for example, inorganic pigments such as carbon black, graphite, molybdenum, red iron oxide, rutile type titanium dioxide coated with titanium dioxide or aluminum oxide, cyanine green, cyanine blue hansa yellow, Benzidine Yellow, Brilliant Carmine 6B, Lake Red C, Permanent Red F
Organic pigments such as 5R can be exemplified.

The proportion of each component (A) to (D) used in the composition of the present invention is as follows: the total amount of component (A) + (B) is 34.7 to 99.7 in the composition of the present invention. % By weight, particularly preferably 49.7 to 99.7% by weight.
When the total amount of the components + (B) is 100 parts by weight,
The usage ratio of the component (A) and the component (B) is as follows.
The amount is preferably 1 to 99 parts by weight, particularly preferably 20 to 80 parts by weight.
The amount of the component (B) is preferably from 1 to 99 parts by weight, particularly preferably from 20 to 80 parts by weight. Component (C) is preferably from 0.3 to 15% by weight, particularly preferably from 1 to 10% by weight. (D) The component is 0 to 70% by weight.
Is particularly preferable, and 0 to 60% by weight is particularly preferable.

The energy ray-curable composition of the present invention comprises a mixture, dissolution, dispersion and kneading of a cationically polymerizable substance (A), a radically polymerizable substance (B), a photopolymerization initiator (C) and a pigment (D). Can be prepared.

The curable composition of the present invention can be cured to a dry state to the touch or a solvent-insoluble state after 0.1 seconds to several minutes by irradiating energy rays such as ultraviolet rays. Any suitable energy ray may be used as long as it has an energy that induces the decomposition of the photopolymerization initiator. It is preferable to use energy rays having a wavelength of 〜500 nm. Exposure to the energy beam depends on the intensity of the energy beam, but is usually 0.1 sec to 1 sec.
About 0 seconds is enough. However, it is preferred to spend more time on relatively thick painted objects. 0.1 seconds to several minutes after the irradiation with the energy beam, the resin is cured by polymerization, but it is sometimes preferable to use heating in order to promote the polymerization reaction.

In the present invention, a solvent for dilution and a resin for modification (for example, an acrylic polymer, a polyurethane polymer, a polyester elastomer, a polyvinyl chloride polymer, an acrylonitrile rubber, etc.) as far as the polymerization is not impaired. Alternatively, for example, an organic carboxylic acid or an acid anhydride nucleus may be used for the purpose of improving electric characteristics, or a polyol or a flexible prepolymer may be mixed for the purpose of imparting rubber elasticity. Furthermore, if necessary, a photoradical polymerization initiator and a photocationic polymerization initiator can be added.

The composition of the present invention further comprises a dye, a filler,
Antistatic agent, flame retardant, defoamer, flow regulator, light stabilizer,
Coupling agents, organic solvents, and the like can be mixed and used. The composition of the present invention can be used for metal, wood, paper, rubber, plastic, glass, ceramic products and the like. Further, specific uses of the present invention include white ink for metal cans such as food cans, various printing inks, paints,
A resist ink, a filler, and the like are included.

[0054]

The present invention will be described below in more detail with reference to examples. Parts in Examples are parts by weight. Examples 1 to 3 and Comparative Examples 1 and 2 An energy ray-curable composition was blended according to the blending composition shown in Table 1 (the numerical values are parts by weight) and kneaded with a three-roll mill. This was applied on an aluminum plate to a thickness of 10 μm with a bar coater, and a metal halide lamp (80
(W / cm ² ) and cured by irradiating ultraviolet rays from a distance of 8 cm. The curability of the prepared composition and the gloss of the cured coating film were tested. Table 1 shows the results.

Curability: The cured coating film was rubbed 50 times with absorbent cotton impregnated with methyl ethyl ketone, and the irradiation amount (mJ / cm ² ) at which the coating film did not change was measured. Luster: The cured coating film was rubbed 50 times with absorbent cotton impregnated with methyl ethyl ketone, and the irradiation amount (mJ
/ cm ² ), the surface of the cured coating film was visually judged.・ ・ ・: Good gloss. Δ: There is slight cloudiness. X: No gloss at all.

[0056]

Table 1 Example Comparative Example 12 3 12 (A) Component 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate 22 11 22 22 22 Bisphenol A diglycidyl ether 11 (B) Component KAYARAD DPHA * 1 22 22 11 22 22 Aronix M-315 * 2 11 (C) component SP-170 * 35 UVI-6990 * 46 PCI-019T * 5 3.0 PCI-021T * 6 3.0 PCI-061T * 7 3.0 (D) component Titanium dioxide (rutile type) 50 50 50 50 50 Other components Polyester resin * 8 6 6 6 6 6 Surfactant (L-7604) * 9 0.4 0.4 0.4 0.4 0.4 Curability (mJ / c ²⁾ ) 137 350 137 1000 or more 1000 or more Gloss ○ ○ ○ × ×

Note) * 1 KAYARAD DPH
A: Dipentaerythritol penta and hexaacrylate mixture, manufactured by Nippon Kayaku Co., Ltd. * 2 Aronix M-315: Toa Gosei Chemical Co., Ltd.
Manufactured by Tris (acryloxyethyl) isocyanurate. * 3 SP-170: a cationic photopolymerization initiator manufactured by Asahi Denka Kogyo KK Propylene carbonate 40% diluted product,
No absorption at a wavelength of 360 nm or more. * 4 UVI-6990: Union Carbide Co., Ltd.
, A cationic photopolymerization initiator. Propylene carbonate 5
0% diluted product, no absorption at a wavelength of 360 nm or more. * 5 PCI-019T: Nippon Kayaku Co., Ltd., photopolymerization initiator, yellow powder, molar absorption coefficient at a wavelength of 387 nm 4
170, the structural formula is

[0058]

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* 6 PCT-021T: Photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd. Yellow powder wavelength 385 nm, molar extinction coefficient 3840, structural formula is

[0060]

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* 7 PCT-061T: a photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd. Yellow powder, molar extinction coefficient 4730 at a wavelength of 385 nm, structural formula is

[0062]

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* 8 Polyester resin: “Vylon 220” manufactured by Toyobo Co., Ltd. Molecular weight: 2000 to 3000 * 9 L-7604: manufactured by Nippon Unicar, a surfactant.

As is clear from the results in Table 1, the composition of the present invention is excellent in curability, gloss and the like even without containing a photo-radical polymerization initiator.

[0065]

The energy ray-curable composition of the present invention comprises:
The combination of photocationic polymerization initiating ability and photoradical polymerization initiating ability is also curable, especially in pigment systems, by using a photopolymerization initiator having a wavelength of 360 nm or more and a maximum molar extinction coefficient of 100 or more.
Excellent in gloss and the like, giving a cured product with excellent physical properties.

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Claims (3)

[Claims] 1. A photopolymerization initiator (C) which is a cationic polymerizable substance (A), a radical polymerizable substance (B), an onium salt having a maximum molar extinction coefficient of not less than 100 at a wavelength of 360 nm or more, and a pigment as an optional component An energy ray-curable composition comprising (D). 2. An energy ray-curable composition, wherein the photopolymerization initiator (C) as the onium salt according to claim 1 is an onium salt having a thioxanthone structure. 3. A cured product of the composition according to claim 1 or 2.