JPH07173279A - Production of cured material - Google Patents

Abstract

PURPOSE:To produce a cured material more quickly without detriment to physical properties, such as hardness, tensile strength, elongation, heat resistance and chemical resistance. CONSTITUTION:A composition consisting of a compound having at least one oxetane ring in the molecule and a cationic polymerization initiator and curable by actinic radiation is irradiated with actinic radiation in an atmosphere of nitrogen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for promptly producing a cured product of a composition having an oxetane ring by irradiating the composition with an active energy ray such as an ultraviolet ray or an electron beam. The obtained cured product is used in various fields such as painting and printing.

[0002]

2. Description of the Related Art The active energy ray curing technology has various properties such as a high curing rate, good workability due to the absence of solvent in general, and extremely low energy requirement.
It has become extremely important in various industries such as wood coating, metal painting and printing. In the early development in this field, research has been concentrated on active energy ray initiated radical polymerization for polyfunctional acrylates and unsaturated polyesters, and even today, these polyfunctional acrylates and unsaturated polyesters, etc. The material consisting of is still used in large quantities. Even now, most of these studies are directed to active energy ray initiated radical polymerization, but photoinitiated ionic polymerization is well recognized to be quite promising in many fields of application, and a wide variety of Due to the great potential to achieve various chemical and physical properties through the polymerization of monomers,
It is attractive. To date, the development of photo-initiated cationic polymerization technology has been focused on epoxy resin and vinyl ether compound having an oxirane ring, which is a three-membered cyclic ether.
Concentrated on different types of monomers. In particular, the photo-curing epoxy resin is known to have excellent adhesiveness, and the cured film has excellent physical properties such as hardness, tensile strength and elongation, high heat resistance, and good chemical resistance. There is. However, the conventional photocurable epoxy resin has a defect that the photocuring speed is comparatively slow, and therefore, it can be used for applications such as paper or plastic coating which requires rapid photocuring. There wasn't. Therefore, it has been earnestly desired to improve the curing speed while making the best use of the characteristics of the epoxy resin. In recent years, it has been reported that a polyfunctional oxetane monomer having a plurality of oxetane rings, which are 4-membered cyclic ethers, as a polymerizable functional group has a photocurability equal to or higher than that of the corresponding polyfunctional epoxide ( Journal of Macromolecular Science. Volume 29, No. 10, 915, 1992,
Vol. A30, No. 2 & 3, 173, 1993, A3
0, 2 & 3, 189, 1993), a photocurable composition containing a polyfunctional oxetane monomer as a main component is proposed as having fast curability (Japanese Patent Application No. 5-4).
9907).

[0003]

However, the curing rate when the above polyfunctional oxetane monomer is used is
Although it is faster than the epoxy resin, it is still much slower than the acrylic active energy ray radical polymerization. Therefore, a photocurable resin having a cyclic ether such as an oxirane ring or an oxetane ring as a polymerizable group has good heat resistance, adhesiveness and chemical resistance, but it requires prompt photocuring. It was difficult to apply for the purpose.

The object of the present invention is to provide a method for producing a cured product of an active energy ray-curable composition which solves the above problems, that is, without impairing the physical properties such as hardness, tensile strength, elongation, heat resistance and chemical resistance. It is an object of the present invention to provide a method capable of producing a cured product faster.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above-mentioned circumstances, and as a result, in an active energy ray-curable composition comprising a compound having at least one oxetane ring in the molecule, under a nitrogen atmosphere. The present invention has been completed by finding that the method of irradiating the composition with active energy rays to cure the composition can produce a cured product faster than the case where the composition is similarly cured in the air.

That is, the present invention is characterized in that an active energy ray-curable composition comprising a compound having one or more oxetane rings in a molecule and a cationic polymerization initiator is irradiated with an active energy ray in a nitrogen atmosphere. And a method for producing a cured product.

Conventionally, in the photo-curing of epoxy resin,
With light irradiation under air atmosphere and light irradiation under nitrogen atmosphere,
Despite the report that there is no difference in curing rate (Journal of Polymer Science, Part A, Volume 28, page 3429, 1990), the compounds having an oxentane ring as in the present invention have a nitrogen atmosphere. It is truly surprising that below it can bring such an excellent cure rate. The present invention will be described in detail below.

Compound Having One or More Oxetane Rings in the Molecule The compound having one or more oxetane rings in the molecule used in the present invention (hereinafter referred to as compound A) is
Examples thereof include compounds having one oxetane ring and compounds having two or more oxetane rings in the molecule.

Compound Having One Oxetane Ring in the Molecule In the present invention, various compounds can be used as the compound having one oxetane ring in the molecule, and a preferable compound is represented by the following formula (1) The compound represented by

[0010]

[Chemical 1]

Here, in the formula (1), Z is an oxygen atom or a sulfur atom. R ¹ is a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a propyl group, a butyl group or the like, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, or a furyl group. Or a thienyl group. R ² is an alkyl group having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group or butyl group, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl- 1 to 2 carbon atoms such as 2-propenyl group, 1-butenyl group, 2-butenyl group or 3-butenyl group
6 alkenyl groups, phenyl groups, benzyl groups, fluorobenzyl groups, aryl groups such as methoxybenzyl groups, phenoxyethyl groups, etc., propylcarbonyl groups, butylcarbonyl groups, pentylcarbonyl groups, etc., with 1 to 6 carbon atoms
1-6 carbon atoms such as alkylcarbonyl group, ethoxycarbonyl group, propoxycarbonyl group or butoxycarbonyl group, etc. alkoxycarbonyl group, ethoxycarbamoyl group, propylcarbamoyl group or butylpentylcarbamoyl group Alkoxycarbamoyl group and the like.

In the present invention, in the above formula (1), R ¹
Is preferably a lower alkyl group, more preferably an ethyl group. R ² is preferably a butyl group, a phenyl group or a benzyl group. Z is preferably oxygen.

Compounds having two or more oxetane rings in the molecule In the present invention, various compounds can be used as the compound having two or more oxetane rings in the molecule. The compound represented by 2) can be mentioned.

[0014]

[Chemical 2]

Here, in the formula (2), m is 2, 3 or 4, and Z is an oxygen atom or a sulfur atom. R ³ is a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a propyl group, a butyl group or the like, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group or furyl. It is a base. R ⁴ is, for example, a linear or branched alkylene group having 1 to 12 carbon atoms or a linear or branched poly (alkyleneoxy) group represented by the following formula (3).

[0016]

[Chemical 3]

In the above formula (3), R ⁵ is a methyl group,
A lower alkyl group such as an ethyl group or a propyl group.

R ⁴ may also be a polyvalent group selected from the group consisting of the following formulas (4), (5) and (6).

[0019]

[Chemical 4]

In the formula (4), n is 0 or 1 to 200.
It is an integer of 0. R ⁶ is a group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, and the following formula (7).

[0021]

[Chemical 5]

In the formula (7), j is 0 or 1 to 100.
And R ⁸ is alkyl having 1 to 10 carbon atoms. R ⁷ is an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group.

[0023]

[Chemical 6]

In the formula (5), R ⁹ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, an alkoxy group having 1 to 10 carbon atoms, and a halogen. An atom, a nitro group, a cyano group, a mercapto group, a lower alkylcarboxylate group or a carboxyl group.

[0025]

[Chemical 7]

In the formula (6), R ¹⁰ is an oxygen atom, a sulfur atom, NH, SO, SO ₂ , CH ₂ , C (CH ₃ ) ₂ or C (CF ₃ ) ₂ .

In the present invention, in the above formula (2), R ³
Is preferably a lower alkyl group, more preferably an ethyl group. As R ⁴ , a group in which R ⁹ is a hydrogen atom in the formula (5), a hexamethylene group, and a group in which R ⁵ is an ethyl group in the formula (3) are preferable. Also, R ⁷ and R ⁸
Is preferably methyl. Z is preferably an oxygen atom.

Other preferred specific examples of the compound having two or more oxetane rings in the molecule include the compounds of formula (8) and formula (9).

[0029]

[Chemical 8]

[0030]

[Chemical 9]

In the formula (8), r is an integer of 25 to 200, and R ¹¹ is an alkyl group having 1 to 4 carbon atoms or a trialkylsilyl group.

In the present invention, the above compound A is used as a composition.
Two or more of the above may be used in combination.

Cationic Polymerization Initiator The cationic polymerization initiator used in the present invention is a compound (hereinafter referred to as compound B) that initiates cationic polymerization upon irradiation with active energy rays, and its representative example is a wide variety of conventionally known compounds. It is a cationic photopolymerization initiator. Among these initiators, preferred are diaryl iodonium salts and triaryl sulfonium salts. A typical photopolymerization initiator is shown below.

[0034]

[Chemical 10]

[0035]

[Chemical 11]

[0036]

[Chemical 12]

[0037]

[Chemical 13]

In the formula, R ¹² is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms of various lengths, or an alkoxy group having 1 to 18 carbon atoms, M is a metal, preferably antimony, and X is A halogen atom, preferably a fluorine atom, n
Is the valence of the metal, for example 5 in the case of antimony. R ¹³ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkoxy group, preferably a hydroxyethoxy group.

Active energy ray-curable composition In the active energy ray-curable composition according to the invention, 100 parts by weight of the compound A is added to the compound B in an amount of 0.
The amount is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight. If the compounding amount is less than 0.01 part by weight, the composition may not be sufficiently cured, and if it exceeds 20 parts by weight,
In some cases, the light transmittance becomes poor and uniform curing cannot be performed.

The composition used in the present invention may contain an epoxy resin in addition to the compounds A and B. As the epoxy resin, any monomer, oligomer or polymer can be used as long as it has been conventionally used as an epoxy resin. Specific examples of the epoxy resin, conventionally known aromatic epoxy resin,
Examples thereof include alicyclic epoxy resin and aliphatic epoxy resin. Incidentally, hereinafter, the epoxy resin means a monomer, an oligomer or a polymer.

Preferred as the aromatic epoxy resin is a di- or polyglycidyl ether produced by reacting a polyhydric phenol having at least one aromatic nucleus or its alkylene oxide adduct with epichlorohydrin, for example, bisphenol. A or a di- or polyglycidyl ether of its alkylene oxide adduct, hydrogenated bisphenol A or a di- or polyglycidyl ether of its alkylene oxide adduct,
Other examples include novolac type epoxy resin. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

The alicyclic epoxy resin is obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. The cyclohexene oxide- or cyclopentene oxide-containing compound thus obtained is preferable, and specific examples thereof include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate.

Preferred aliphatic epoxy resins include aliphatic polyhydric alcohols or di- or polyglycidyl ethers of their alkylene oxide adducts.
As typical examples thereof, diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, di- or tri-glycerin or its alkylene oxide adduct. Examples thereof include polyglycidyl ethers of polyhydric alcohols such as glycidyl ether, diglycidyl ethers of polyethylene glycol or its alkylene oxide adducts, and diglycidyl ethers of polyalkylene glycols such as polypropylene glycol or its diglycidyl ether of alkylene oxide adducts. . Examples of the alkylene oxide include ethylene oxide and propylene oxide. In addition to these compounds, it is also possible to use monoglycidyl ether of aliphatic higher alcohol, which is a monomer having one oxirane ring in the molecule, monoglycidyl ether of phenol, cresol or alkylene oxide adducts thereof. it can.

The mixing ratio of the epoxy resin is preferably 5 to 80 parts by weight based on 100 parts by weight of the total amount of the compound A in the composition.

In addition to the above epoxy resin, the composition used in the present invention also contains an inert component such as an inorganic filler, a dye, a pigment, a viscosity modifier, a treating agent and an ultraviolet blocking agent. It may be.

In the case of curing with ultraviolet rays, a photosensitizer may be added to the compound B for the purpose of further improving the curability. As a typical sensitizer that can be used, it is possible to use the compounds disclosed by Klibero in Advanced in Polymer Science [Adv. In Plymer Sci., 62, 1 (1984)]. Examples include pyrene, perylene, acridine orange, thioxanthone,
There are 2-chlorothioxanthone and penzoflavin.

Production Method of Cured Product The production of the cured product in the present invention is performed by irradiating the active energy ray-curable composition with an active energy ray such as an ultraviolet ray, an X-ray or an electron beam in a nitrogen atmosphere. Be broken. In this case, usually, the active energy ray-curable composition is applied to a substrate such as metal, rubber, plastic, molded part, film, paper, wood, glass cloth, concrete or ceramic, and the active energy ray is applied thereto. Irradiate. When irradiating with ultraviolet rays, various light sources can be used, for example, a mercury arc lamp, a xenon arc lamp,
It can be cured with fluorescent lamps, carbon arc lamps, tungsten-halogen copying lamps and irradiation light from ambient sunlight. The irradiation intensity of ultraviolet rays is at least 0.01 watt square centimeter. 1 if the curing is carried out continuously, for example on a paper or metal coating line
It is preferable to set the irradiation rate so that the composition can be cured within 20 seconds. In the case of curing with an electron beam, it is usually cured with an electron beam having an energy of 300 eV or less, but it is also possible to cure instantaneously with an irradiation dose of 1 Mrad to 5 Mrad. The production method of the present invention uses, for example, protection, decoration and insulation coatings, encapsulants, printing inks, sealants, adhesives, photoresists, wire insulation materials, textile coatings, laminates and impregnations using the above-mentioned composition. It can be used for manufacturing tapes, printing plates and the like.

[0048]

EXAMPLES The present invention will be described more specifically below with reference to Examples and Comparative Examples. Example 1 As a compound A, 100 parts (part by weight, the same applies hereinafter) of a compound (14) of the following formula, and as a compound B, 2 parts of diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate were added and mixed to activate. An energy ray-curable composition was prepared.

[0049]

[Chemical 14]

A fiber type ultraviolet irradiation apparatus [manufactured by Ushio Co., Ltd., Spot Cure] using a high-pressure mercury lamp of 250 W in a nitrogen atmosphere was applied to a base material coated with an aluminum plate to a thickness of about 10 μm. UIS-25102]
FT-IR device [made by Nicolet Co., Ltd., MAGNA-I
R 550] and was irradiated with ultraviolet rays at an irradiation intensity of 27 mW / cm ² . 980 by real-time FT-IR method
The reactivity of the composition was evaluated by measuring the rate of decrease of the characteristic absorption of the oxetane ring at cm ^{-1 at} a specific time. The result is shown in FIG. In FIG. 1, the vertical axis represents the conversion rate of compound A, and the horizontal axis represents the irradiation dose [irradiation intensity × time (s
ec)] is meant. Also, in a nitrogen atmosphere, a sufficient irradiation amount (1000 mj / c) to complete the reaction of the composition is obtained.
It was cured by irradiating it with ultraviolet rays of m ² ) and the molecular weight of the obtained cured product was measured by GPC.

Example 2 A composition was prepared in the same manner as in Example 1 except that the following compound (15) was used as the compound A.

[0052]

[Chemical 15]

The reactivity of the obtained composition was evaluated by the real-time FT-IR method in the same manner as in Example 1. The result is shown in FIG. Also, under a nitrogen atmosphere,
The composition was cured in the same manner as in Example 1 at an irradiation dose of 1000 mj / cm ² , and the molecular weight of the cured product was measured. The results are shown in Table 1.

Examples 3 and 4 The following compounds (16) and (17) were used as the compound A,
A composition was prepared in the same manner as in Example 1.

[0055]

[Chemical 16]

[0056]

[Chemical 17]

The reactivity of the obtained composition was evaluated by the real-time FT-IR method as in Example 1.
The result is shown in FIG. In Examples 3 and 4, the minimum irradiation dose (tack-free energy) at which the surface was not sticky was measured. The results are shown in Table 1.

[0058]

[Table 1]

Comparative Examples 1 to 4 Compounds (14) to (17) were used as compound A, and compositions were prepared in the same manner as in Example 1. The reactivity of the composition was evaluated in the same manner as in Example 1 except that the ultraviolet irradiation was performed in the air at an irradiation intensity of 275 mW / cm ² . The result is shown in FIG. In Comparative Examples 1 and 2, 10
Each composition was cured at an irradiation dose of 000 mj / cm ² , and the molecular weight was measured in the same manner as in Example 1. or,
In Comparative Examples 3 and 4, the tack-free energy was measured as in Examples 3 and 4.

[0060]

[Table 2]

FIG. 1 (Examples 1 to 4) and FIG. 2 (Comparative Examples 1 to 1)
When comparing 4), it is apparent that the curing rate in the nitrogen atmosphere of Examples 1 to 4 is faster than the curing rate in the air atmosphere. In addition, Example 1
According to the comparison of the molecular weights of Comparative Examples 1 and 2 with Comparative Examples 1 and 2, the curing rate in the nitrogen atmosphere (Examples 1 and 2) did not apparently increase the curing rate due to chain transfer, etc. You can see that it is progressing. Furthermore, in the comparison of the tack-free energies of Examples 3 and 4 and Comparative Examples 3 and 4, curing in a nitrogen atmosphere (Example 3
In addition, it can be seen that the curing rate of 4) and 4) is higher than that of curing in an air atmosphere.

[0062]

The method for producing a cured product of the present invention is capable of rapidly producing a cured product by irradiating an active energy ray-curable composition with an active energy ray such as an ultraviolet ray or an electron beam. Since it does not impair the various physical properties of, such as protection, decoration or insulating coating, potting compound, printing ink, sealant, adhesive, photoresist, wire insulating material, textile coating, laminate, impregnated tape or printing plate, etc. It can be used for manufacturing and has a great impact on industry.

[Brief description of drawings]

FIG. 1 is a diagram showing the reactivity of each composition in Examples 1 to 4.

FIG. 2 is a diagram showing the reactivity of each composition in Comparative Examples 1 to 4.

Claims (1)

[Claims] 1. A cured product obtained by irradiating an active energy ray-curable composition comprising a compound having one or more oxetane rings in the molecule and a cationic polymerization initiator with an active energy ray in a nitrogen atmosphere. Manufacturing method.