JPH1060098A - Energy ray curable composition and its cured material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition useful for various kinds, coating materials, etc., capable of exhibiting excellent curing properties and providing a cured material excellent in luster, by adding a pigment and a specific photocationic polymerization initiator to a cationic polymerizable substance. SOLUTION: This composition comprises (A) a cationic polymerizable substance such as an epoxyether of the formula (R is a 5-12C aliphatic or alicyclic group; (n) is 1-3), (B) a pigment and (C) a photocationic polymerization initiator which is an onium salt such as an onium salt containing a thioxanthone structure [e.g. bis(p-tolyl).(5, 7-diethythioxanthone-2-yl)sulfonium hexafluoroantimonate] and has >=500 absorption coefficient of maximum mol at 360-600nm, especially 360-500nm wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an energy ray-curable composition containing a novel pigment. More specifically, the present invention relates to an energy ray-curable composition excellent in curability, particularly excellent in curability of a composition containing a pigment, and a cured product thereof.

[0002]

2. Description of the Related Art Photopolymerizable compositions include printing inks, paints,
In the fields of coating, liquid resist ink, etc.
Research has been actively conducted from the demands of energy saving, space saving, and no pollution, and practical application has been studied. However, most of these studies were based on radical polymerization reactions of double bonds. Cationic polymerizable substances, for example, epoxy resins are excellent materials in physical properties, but are difficult to photopolymerize, and so far, materials that introduce double bonds by acrylic modification have been mainly used. .

[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 poor, and no improvement has been proposed. 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 present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have succeeded in providing an energy ray-curable composition having excellent curability and a cured product thereof. That is, the present invention relates to (1) a cationically polymerizable substance (A) and a pigment (B),
(2) (1) An energy ray-curable composition comprising a photocationic polymerization initiator (C), which is an onium salt having a maximum molar extinction coefficient of 500 nm or less (preferably 500 nm or less). An energy ray-curable composition, wherein the cationic photopolymerization initiator (C) is an onium salt having a thioxanthone structure,
(3) A cured product of the composition described in (1) or (2).

In the practice of the present invention, specific examples of preferred cationically polymerizable substances (A) include, for example, the following three different epoxy resins which can be cured at ordinary atmospheric temperature. Those belonging to the first group consist of epoxy ethers having the following structural formula

[0006]

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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

[0008]

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And epoxy carbocyclic ethers having Here, R ¹ may be mononuclear or polynuclear, and is an epoxidized carbocyclic group having 4 to 12 carbon atoms in its ring structure. Alkyl groups R ² is C ₁ ~C ^_3, R ₃ is R
^It may be the same as ¹ or an epoxy group having the following general structural formula.

[0010]

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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.

Preferred cationic polymerizable substances (A) other than the epoxy resin include vinyl compounds, for example, vinyl 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 Vinyl ethers such as ethers, phenol novolak polyvinyl ethers, etc .; acrolein; 1-vinylpyrene and acenaphthalene. Vinyl alicyclic compounds such as vinyl cyclohexane; a vinyl allenes isobutylene, conjugated diene, such as butadiene, isoprene or the like is wrapped. Further, oxetanes and oxolanes (eg, tetrahydrofuran and trioxane) can also be used. Other classes of compounds include β-lactones, for example, cyclic esters such as propiolactone and 1,3,3,3.
-Cyclic amines such as 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 urea / formaldehyde resins and phenol / formaldehyde resins as described in U.S. Pat. No. 4,102,687 issued to Crivello on Jul. 15, 1978. And thermosetting aldehyde condensed organic resins such as melamine / formaldehyde resin.

The cationically polymerizable substance suitable for the present invention is Pa
"UVCURING; SCIENCE AND of ppas
TECHNOLOGY "(Stamford, CT, Technology Marking Cprporation); Crivello, U.S. Patent Nos. 4,150,988; 4,102,687; These are monomeric or oligomeric substances having at least one functional epoxy group or an oxirane ring so as to be polymerizable by opening the oxirane ring or at least one functional epoxy group or an oxirane ring so as to be polymerizable by opening the oxirane ring. In addition, it is permissible to use polymeric epoxy compounds if they can be dispersed in the composition and further polymerized or crosslinked to give a strong polymer. It may be of an aromatic, alicyclic, aromatic or heterocyclic group.

It is preferable to use an epoxy resin alone or in combination as the polymerizable epoxy compound.
They also have an average epoxy equivalent of about 50-500.
A value of 0 is preferred. 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, the most well-known being the reaction of bisphenol A with epichlorohydrin, phenol novolak, the reaction of cresol novolak with epichlorohydrin, aliphatic glycidyl ether compounds, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, vinylcyclohexene dioxide, 2- [3,4-epoxycyclohexyl-5,
[5-spiro-3,4-epoxy] cyclohexane-metadioxane, alicyclic epoxy compounds such as 1,2-epoxy-p-vinylcyclohexene and the like.

In the present invention, the pigment (B) is used. Specific examples of the pigment (B) include, for example, carbon black,
Inorganic pigments such as graphite, molybdenum red, red iron oxide, titanium dioxide or rutile titanium dioxide coated with aluminum oxide, cyanine green, cyanine blue, Hansa yellow, benzidine yellow, brilliant carmine 6B, lake red C, permanent red F5R And the like.

In the present invention, a cationic photopolymerization initiator (C) which is an onium salt having a wavelength of 360 nm or more and a maximum molar extinction coefficient of 500 or more is used. Specific examples of the cationic photopolymerization initiator (C) include, for example,

[0018]

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[0019]

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[0020]

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[0021]

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[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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Onium salts which are sulfonium salts having a thioxanthone structure, such as

[0029]

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[0030]

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[0031]

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[0032]

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

[0034]

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[0035]

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Onium salts, which are sulfonium salts having an acridone structure, can be mentioned. Particularly preferred onium salts in the present invention include:

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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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 at wavelengths not absorbed by the pigment, and have a wavelength of 360n.
When the absorption is not more than m and the molar extinction coefficient is 50 or less, the resin does not cure or the curing is slow. The maximum cationic extinction coefficient at 360 nm or more of the cationic photopolymerization initiator (C) used in the present invention is 500 or more, preferably 1,000 or more, and particularly preferably 2,000 or more.

The use ratio of each of the components (A) to (C) of the composition of the present invention is preferably 34.7 to 98.7% by weight, particularly preferably 49.7 to 89.7%. (B) component is preferably 1 to 65% by weight, particularly preferably 10 to 50% by weight, and component (C) is
It is preferably from 0.3 to 15% by weight, particularly preferably from 1 to 1% by weight.
0% by weight.

The energy ray-curable composition of the present invention can be prepared by mixing, dissolving and kneading the cationically polymerizable substance (A), the pigment (B) and the cationic photopolymerization initiator (C).

The curable composition of the present invention can be cured to a touch-dry state or a solvent-insoluble state after 0.1 seconds to several minutes by irradiating energy rays such as ultraviolet rays. The appropriate energy ray may be any as long as it has energy that induces the decomposition of the photocationic polymerization initiator, but is preferably obtained from a high or low pressure mercury lamp, a xenon lamp, a metal halide lamp, a germicidal lamp, a laser beam, or the like. It is preferable to use an energy ray having a wavelength of 200 nm to 500 nm. Exposure to energy rays depends on the intensity of the energy rays, but usually 0.1
About 10 to 10 seconds is sufficient. However, it is preferred to spend more time on relatively thick painted objects. After 0.1 seconds to several minutes after the irradiation with the energy beam, most of the compositions dry to the touch by cationic polymerization, but it is sometimes preferable to use heating in combination to promote the cationic polymerization reaction.

The present invention further includes a solvent for dilution and non-reactive resins for modification (for example, acrylic polymer, polyurethane polymer, polyester elastomer, polyvinyl chloride polymer, Epoxy (meth) acrylate which is a reaction product of (meth) acrylic acid and epoxy resin such as acrylonitrile rubber) and (meth) acrylic acid ester compound (for example, bisphenol A type epoxy resin, novolak type epoxy resin, etc.) A) a reaction product of an acrylate and a polybasic anhydride (for example, succinic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc.), oligomers such as urethane (meth) acrylate and polyester poly (meth) acrylate; Hydroxyethyl (meth) ac Rate, 1,6-hexanediol di (meth) acrylate, nonanediol (meth)
Monomers such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol penta and hexa (meth) acrylate ) Can be blended. When a (meth) acrylic acid ester compound is used, a photo-radical polymerization initiator (for example, 1-hydroxycyclohexyl phenyl ketone, acetophenone dimethyl ketal, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide, bisacyl phosphite) Preferably, fin oxide is used. Further, for example, an organic carboxylic acid or an acid anhydride can be used for the purpose of improving electric characteristics, or a polyol or other flexible prepolymer can be mixed for the purpose of imparting rubber elasticity.

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.

[0049]

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.

[0051]

Table 1 Example 1 Comparative Example 1 2 3 1 2 Cationic polymerizable substance (A) 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate 50 45 45 45 45 bisphenol A diglycidyl ether 10 10 10 10 Pigment (B) Titanium dioxide 50 45 45 45 45 Photocationic polymerization initiator (C) SP-170 * 15 5 UVI-6990 * 26 PCI-019T * 33 PCI-021T * 43 PCI-061T * 53 BYKP-108 (dispersant) * 6 0.5 0.5 0.5 0.5 0.5 (leveling agent) * 7 1.0 1.0 1.0 1.0 1.0 Curability (mJ / cm ² ) 137 400 92 450 1110 Gloss ○ ○ ○ × ×

Note) * 1 SP-170: a cationic photopolymerization initiator manufactured by Asahi Denka Kogyo KK Propylene carbonate 40% diluted product, no absorption at wavelength of 360nm or more. * 2 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. * 3 PCI-019T: a cationic photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd. Yellow powder, molar extinction coefficient 4170 at a wavelength of 387 nm, structural formula is

[0053]

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* 4 PCT-021T: Photocationic polymerization initiator manufactured by Nippon Kayaku Co., Ltd. Yellow powder, wavelength 38
The molar extinction coefficient at 5 nm is 3840, and the structural formula is

[0055]

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* 5 PCT-061T: a cationic photopolymerization initiator manufactured by Nippon Kayaku Co., Ltd. Yellow powder, wavelength 38
Molar extinction coefficient 4730 at 5 nm, structural formula is

[0057]

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As is clear from the results in Table 1, the composition of the present invention is excellent in curability and gloss.

[0059]

The energy ray-curable composition of the present invention comprises:
It has excellent curability and gloss, and gives a cured product with excellent physical properties.

Claims (3)

[Claims] The present invention is characterized in that it contains a cationically polymerizable substance (A), a pigment (B), and a cationic photopolymerization initiator (C) which is an onium salt having a maximum molar extinction coefficient of 500 or more at a wavelength of 360 nm or more. Energy curable composition. 2. An energy ray-curable composition wherein the cationic photopolymerization initiator (C) 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.