JP2003128715A - Aqueous composition curable with actinic energy ray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous composition curable with actinic energy rays such as ultraviolet rays and electron beams and suitably applicable to various uses, more particularly, provide an actinic energy ray curable aqueous composition giving decreased load on the environment and having low viscosity and sufficiently quick curability suitable for the formation of a cured product and accordingly applicable to various uses. SOLUTION: The aqueous composition curable with actinic energy rays contains a water-soluble acetophenone-based polymerization initiator, a water-soluble polymerizable compound, a water-soluble tertiary amine compound and water.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an active energy ray-curable aqueous composition. Specifically, it relates to an aqueous composition that is cured by active energy rays such as ultraviolet rays and electron rays.

[0002]

2. Description of the Related Art Compositions and their techniques which are cured by irradiation with active energy rays include various resists, ultraviolet curable coatings,
It is used in a wide range of fields such as UV curable adhesives. For example, in the case of an ultraviolet curable coating material, a thin film having a thickness of several μm or less is coated on the surface of a substrate, but a low viscosity composition of 10 mPa · s or less is required to obtain such a thin film. In order to obtain such a low-viscosity composition, a composition in which an organic solvent such as toluene or methyl ethyl ketone accounts for more than half of the total weight of the composition is used.

However, in recent years, an aqueous photosensitive material has been demanded due to environmental problems. In order to avoid the harmful effects of organic solvents, the design of a water-soluble photosensitive composition is considered as a measure, and it is necessary to make the curing component and the photopolymerization initiator water-soluble.

As a water-soluble curing component, an acrylic monomer or acrylic oligomer containing a hydroxyl group, polyethylene glycol chain, quaternary ammonium salt or carboxylate is known. As water-soluble photopolymerization initiators, acetophenone-based, benzophenone-based, thioxanthone-based and benzoin-based photopolymerization initiators containing a hydroxyl group, polyethylene glycol chain, quaternary ammonium salt or carboxylate are known. However, a sufficient curing rate cannot be obtained with the combination of these curing components and the photopolymerization initiator. In particular, when the acrylate-based monomers and oligomers are formed into a thin film, they are subjected to curing inhibition by oxygen in the air, and therefore irradiation of active energy rays for a considerably long time is required to completely eliminate stickiness on the surface.

In order to solve this, it is conceivable to increase the amount of the photopolymerization initiator or add an N-vinyl compound such as N-vinylpyrrolidone or N-vinylformamide, but the amount of the photopolymerization initiator is increased. The physical properties of the obtained cured product deteriorate, and the cost increases. Addition of the N-vinyl compound has a harmful effect such as toxicity of the monomer and weakness against acid.

[0006] Japanese Patent Application Laid-Open No. 59-4609 discloses a photocurable composition useful for prepreg and the like, which contains a polymerizable ethylenically unsaturated substance, an acetophenone photosensitizer, a dye and a reducing agent. It is disclosed. In this technology, the structure of the acetophenone photosensitizer is specified and it is not water-soluble. Further, German Patent No. 4336299A1 (1995) discloses a method for producing a UV curable acrylic gel for drug delivery, which contains an acrylate monomer, glycerol, water, a photosensitizer and triethanolamine. In this technique, Darocur 1173 is used as a photosensitizer.
(Trade name, manufactured by Ciba Geigy) is used, which is not water-soluble. Furthermore, JP-A-2000-18
Japanese Patent No. 6242 discloses an ink containing a coloring material, a polymerizable oligomer, a photopolymerization initiator and water for use in inkjet recording. In this technique, a photopolymerization initiator having a solubility in water of 3% by weight or more is used. However, even in these technologies, it is necessary to reduce the load on the environment and to exhibit a low viscosity suitable for the formation of a cured product and a sufficient rapid curability by active energy rays such as ultraviolet rays and electron beams. Therefore, there is room for devising the water-based composition so that it can be suitably applied to various uses.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide an active energy ray-curable aqueous composition which can be suitably applied to various uses. To do.

[0008]

Means for Solving the Problems The present inventors have conducted various investigations on active energy ray-curable water-based compositions that can be suitably applied to various applications, and as a result, found that a water-soluble acetophenone-based polymerization initiator, water-soluble Focusing on the fact that a composition containing a polymerizable compound, a water-soluble tertiary amine compound and water can reduce the load on the environment, and can exhibit a low viscosity suitable for the formation of a cured product and a sufficient rapid curing property, and various applications. It has been found that it can be suitably applied to. It has also been found that the inclusion of a water-soluble polymer can prevent bleeding when the composition is applied to a paper substrate. It was also found that sufficient curability can be obtained even in a system containing a colorant. Further, it was found that improvement of curability and improvement of physical properties of the obtained cured product can be achieved by using a polyvinylpyrrolidone homopolymer and / or a polyvinylpyrrolidone copolymer as a water-soluble polymer, and the present invention was conceived. . The water-soluble acetophenone-based polymerization initiator is a so-called self-cleaving type initiator,
Normally, it is not used in combination with a reducing agent such as a tertiary amine compound having an action of extracting hydrogen, but in the present invention, it is conceived that the above problems can be satisfactorily solved by combining as described above. The present invention has been reached.

That is, the present invention is an active energy ray-curable aqueous composition containing a water-soluble acetophenone polymerization initiator, a water-soluble polymerizable compound, a water-soluble tertiary amine compound and water. The present invention is described in detail below.

In the active energy ray-curable aqueous composition of the present invention, the water-soluble acetophenone-based polymerization initiator, the water-soluble polymerizable compound and the water-soluble tertiary amine compound which are essential components are all water-soluble. That is, the solubility in water is specified so that it becomes water-soluble.
In the present specification, the solubility in water is represented by the weight% of the compound dissolved in water at 25 ° C. The solubility in water is judged to be dissolved if it is transparent when the solution is visually observed. Further, the active energy ray-curable water-based composition of the present invention contains such an essential component and, if necessary, other components, but the other components may be soluble in water, It may be dispersed without being dissolved. As described above, in the present invention, the essential component is “water-soluble”, but the composition is “water-based”, that is, all may be water-soluble or some may be water-dispersible. It's good.

The water-soluble acetophenone-based polymerization initiator of the present invention is not particularly limited as long as it is an acetophenone-based polymerization initiator having a solubility in water of 0.1% by weight or more, and one kind or two or more kinds can be used. . Specifically, 1- [4
-(2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Ciba.
Irgacure 2 manufactured by Specialty Chemicals
959) or a hydroxyl group of which a (poly) ethylene glycol chain is introduced, 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals, Irgacure 184) having a hydroxyl group and / or a phenyl group (poly) ethylene. Introduced glycol chain,
-OCH ₂ to the phenyl group of 1-hydroxycyclohexyl phenyl ketone COO ⁺ Na ^- which was introduced, 2-hydroxy-2-methyl-1-one (Ciba Specialty Chemicals Inc., Darocure 1173 ) of hydroxyl and / or the phenyl group (poly) which was introduced ethylene glycol chain, -OCH ₂ to 2-hydroxy-2-methyl-phenyl group COO ⁺ Na ^- was introduced Α-Hydroxyalkylacetophenones such as 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Ciba Specialty Chemicals, Irgacure 907), 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone- (Ciba Specialty Chemicals Inc., Irgacure 369), and the α- -aminoalkylphenone those with the amino group of non acids salified quaternary ammonium, and the like. However, since the active energy ray-curable aqueous composition of the present invention may contain an anionic compound, the nonionic one is preferable to the cationic one from the viewpoint of storage stability.

The amount of the above-mentioned water-soluble acetophenone-based polymerization initiator to be used may be appropriately set depending on the amount and type of the water-soluble polymerizable compound or the water-soluble tertiary amine compound. Of which 0.01% by weight
It is preferably 20% by weight. More preferably 0.
05% to 10% by weight, particularly preferably 0.1% by weight
~ 5% by weight. If the amount used is less than 0.01% by weight, sufficient curability may not be obtained.
If it is used in excess of weight%, it may be disadvantageous in terms of economy.

The water-soluble polymerizable compound in the present invention is not particularly limited as long as it has a solubility in water of 1% by weight or more, and one kind or two or more kinds can be used. Specifically, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate Hydroxyl group-containing (meth) acrylates such as; morpholino group-containing (meth) acrylates such as acryloylmorpholine; pentaethylene glycol di (meth) acrylate, hexaethylene glycol di (meth) acrylate, heptaethylene glycol di (meth) acrylate, octa Polyethylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate; polyvalent hydroxyl group containing such as glycerin and pentaerythritol A compound obtained by reacting (meth) acrylic acid with a part of the hydroxyl groups of the compound; an epoxy acrylate obtained by addition of (meth) acrylic acid to an epoxy resin such as polyethylene glycol diglycidyl ether; hydroxyl for an isocyanate group-containing compound Urethane acrylate obtained by addition of group-containing (meth) acrylate; onium salt-containing (meth) acrylate such as quaternary ammonium salt or sulfonium salt; carboxylic acid or carboxylate-containing (meth) acrylate;
Phosphate ester-containing (meth) acrylates; hydrophilic heterocycle-containing (meth) acrylates such as pyrrolidone and oxazoline; hydroxyl group-containing vinyl ethers such as hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether and hydroxybutyl vinyl ether; polyethylene glycol and anhydrous Examples thereof include unsaturated polyesters obtained by condensation of unsaturated acids such as maleic acid. Among these, polyethylene glycol di (meth) is preferable in terms of physical properties of the cured product.
Acrylate, a compound obtained by reacting (meth) acrylic acid with a part of hydroxyl groups of a polyvalent hydroxyl group-containing compound, and an epoxy acrylate obtained by addition of (meth) acrylic acid to an epoxy resin such as polyethylene glycol diglycidyl ether are particularly preferable. preferable.

The amount of the water-soluble polymerizable compound used may be appropriately set depending on the amounts and types of the water-soluble polymer and the water-soluble tertiary amine compound, the viscosity of the system and the required physical properties of the cured product. It is preferably 1% by weight to 80% by weight based on the entire radiation curable water-based composition. More preferably 2% by weight to 50% by weight, particularly preferably 5% by weight to 2% by weight.
It is 0% by weight. When the amount used is less than 1% by weight, sufficient curability and physical properties of the cured product may not be obtained, and when more than 80% by weight, the viscosity becomes high and workability may be deteriorated.

The water-soluble tertiary amine compound of the present invention has at least one tertiary amino group in one molecule, and is a tertiary amine compound having a solubility in water of 0.1% by weight or more. There is no particular limitation, and one kind or two or more kinds can be used. Specifically, triethanolamine, triisopropanolamine, tributanolamine, methyldiethanolamine, methyldiisopropanolamine, methyldibutanolamine, ethyldiethanolamine, ethyldiisopropanolamine, ethyldibutanolamine, propyldiethanolamine,
Propyldiisopropanolamine, propyldibutanolamine, dimethylethanolamine, dimethylisopropanolamine, dimethylbutanolamine, diethylethanolamine, diethylisopropanolamine, diethylbutanolamine, dipropylethanolamine, dipropylisopropanolamine, dipropylbutanolamine, dibutyl Ethanolamine, dibutylisopropanolamine, dibutylbutanolamine, methylethylethanolamine, methylethylisopropanolamine, methylethylbutanolamine,
Examples thereof include benzyldiethanolamine, N-phenyldiethanolamine, tetraethanolethylenediamine and tetrapropanolethylenediamine. Also,
Polyethylene glycol chain introduced by adding ethylene oxide to these hydroxyl group-containing tertiary amine compounds, and polymerizable double bond by adding a monomer containing a functional group reactive with a hydroxyl group to a hydroxyl group-containing tertiary amine compound It is also possible to use those in which a is introduced, and those in which a tertiary amino group is introduced into a polymer or an oligomer.

The amount of the water-soluble tertiary amine compound used is
It may be appropriately set depending on the amount and type of the water-soluble acetophenone-based polymerization initiator or the water-soluble polymerizable compound, the required physical properties of the cured product, and the like, but 0.01% by weight to the whole active energy ray-curable aqueous composition It is preferably 20% by weight. It is more preferably 0.05% by weight to 10% by weight, and most preferably 0.1% by weight to 5% by weight. When the amount used is less than 0.01% by weight, sufficient curability and physical properties of the cured product may not be obtained, and when used in excess of 20% by weight, coloring and storage stability may not be sufficient. .

The active energy ray-curable aqueous composition of the present invention preferably further contains a water-soluble polymer, and the water-soluble polymer may be a polymer having a solubility in water of 0.1% by weight or more. There is no particular limitation, and one kind or two or more kinds can be used. Specifically, polyvinylpyrrolidone, a copolymer of vinylpyrrolidone and vinyl acetate, a copolymer of vinylpyrrolidone and vinylimidazole, a copolymer of vinylpyrrolidone and (meth) acrylates, polyethylene glycol, polyvinyl alcohol, polyacetic acid. Partial saponification products of vinyl, hydroxyalkyl cellulose and its derivatives, polyacrylamide, water-soluble polyamide derivatives and the like can be mentioned. Among these, polyvinylpyrrolidone homopolymers and / or polyvinylpyrrolidone copolymers are effective in improving the curability and the physical properties of the obtained cured product, and are particularly preferable.

The amount of the water-soluble polymer used may be appropriately set depending on the amount and type of the water-soluble polymerizable compound, the viscosity of the system and the required physical properties of the cured product. Of these, 0.1% to 30% by weight is preferable. More preferably 0.2% by weight to 20
%, Particularly preferably 0.3 to 10% by weight. If the amount used is less than 0.1% by weight, the effect of improving the curability and the physical properties of the cured product may not be obtained.
If it is used in an amount of more than wt.

The molecular weight of the above water-soluble polymer is not particularly limited, but it is preferably 3000 to 10 in terms of weight average molecular weight.
00000, more preferably 10,000 to 20,000
0, particularly preferably 30,000 to 100,000. If the weight average molecular weight is less than 3,000, the effect of improving the curability and the physical properties of the cured product may not be obtained.
If it exceeds 000, the viscosity becomes high and the workability may be deteriorated.

The active energy ray-curable aqueous composition of the present invention preferably further contains a colorant, and the colorant is not particularly limited, and one or more dyes and / or pigments may be used. it can. The amount of them used is not particularly limited, but is preferably 0.1% by weight to 30% by weight based on the entire active energy ray-curable aqueous composition. It is more preferably 0.2% by weight to 20% by weight, and particularly preferably 0.5% by weight to 10% by weight. If the amount used is less than 0.1% by weight, a sufficient coloring effect may not be obtained, and if it is used more than 30% by weight, it may be disadvantageous from the economical point of view.

The amount of water as a solvent used in the present invention is not particularly limited, but it is preferably 10% by weight to 99% by weight of the total active energy ray-curable aqueous composition. It is more preferably 50% by weight to 95% by weight, and particularly preferably 70% by weight to 90% by weight. Usage is 10
If it is less than 10% by weight, the viscosity may be high and the workability may be lowered. If it is used in excess of 99% by weight, the energy required to remove water may be large, which may be disadvantageous from the economical point of view. There is.

In addition to these components, one or more organic solvents may be used as a diluting solvent. Specifically, methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, Examples thereof include, but are not limited to, ethylene glycol dibutyl ether, methyl acetate, ethyl acetate, propyl acetate, butyl acetate and the like.

In the present invention, in addition to these components, a pigment dispersion stabilizer, a defoaming agent, a leveling agent, an antioxidant, a polymerization inhibitor and the like may be added. It is also possible to add a polymerization initiator other than an acetophenone-based polymerization initiator within a range that does not adversely affect the physical properties of the cured product.

The active energy ray used for curing the active energy ray-curable aqueous composition of the present invention is not particularly limited, but active energy rays such as ultraviolet rays and electron rays are preferably used.

[0025]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" is
It means "parts by weight".

Example 1 900 parts of water as a solvent in a beaker, 4.3 parts of Irgacure 2959 (manufactured by Ciba Specialty Chemicals) as a water-soluble acetophenone-based polymerization initiator, and an average as a water-soluble polymerizable compound 87 parts of polyethylene glycol diacrylate having a degree of polymerization of 9 and 8.7 parts of triethanolamine as a water-soluble tertiary amine compound were added,
Stir well with a stirrer. The resulting composition was a completely transparent aqueous solution.

The obtained aqueous solution was applied on a well-defatted glass plate and dried in a hot air dryer at 80 ° C. for 20 minutes, and then the thickness was adjusted to 14 μm with a bar coater. Subsequently, this is an ultraviolet irradiation device (PM25C manufactured by Ushio Inc.)
-100, 250W ultra high pressure mercury lamp used, main wavelength 365n
m) and irradiated with ultraviolet rays having an energy of 43 mJ / cm ² per second, and the surface dryness of the thin film was examined with a finger every second, and it was completely tack-free in 4 seconds of irradiation. Became.

Next, the above aqueous solution is applied onto a paper base material to a thickness of 14
The coating was applied by a bar coater so as to have a thickness of μm, and the bleeding of the coating film at that time was visually determined. Further, the coated paper is irradiated with ultraviolet rays for 10 seconds by the ultraviolet irradiation machine to cure the coating film on the obtained paper base material, and the paper is kept for 25 minutes for 3 minutes.
It was immersed in water at ℃, and the state of the coating film at that time was visually determined. The results are summarized in Table 1.

Examples 2 to 6 Compositions having the formulations shown in Table 1 were prepared in the same manner as in Example 1, and were cured by the same method as in Example 1 and were ultraviolet curable and were applied to a paper substrate. Evaluation of bleeding and a water resistance test of the cured coating film were performed. The results are summarized in Table 1.

Comparative Examples 1 to 4 Compositions having the formulations shown in Table 1 were prepared in the same manner as in Example 1, and were cured by the same method as in Example 1 and were cured by ultraviolet light and applied to a paper substrate. Evaluation of bleeding and a water resistance test of the cured coating film were performed. The results are summarized in Table 1.

[0031]

[Table 1]

The description in Table 1 is as follows. Irgacure 2959: 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Ciba Specialty.
Iodacure 907 iodonium chloride: 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Ciba Specialty Chemicals, Irgacure 907). Compound PEGDA (n = 9) obtained by reaction with methyl iodide: diacrylated polyvinylpyrrolidone of polyethylene glycol having an average degree of polymerization of 9: weight average molecular weight = 45,000 polyethylene glycol: weight average molecular weight = 70,000 * : Irradiation energy = 43 mJ / cm ² · sec **: Evaluation standard ○ = No bleeding, △ = Some bleeding, × = Large bleeding ***: Evaluation standard ○ = No change, △ = Some bleeding, × = Painting Membrane dissolves in water

[0033]

EFFECT OF THE INVENTION The active energy ray-curable aqueous composition of the present invention has the above-mentioned constitution, can reduce the load on the environment, and can exhibit a low viscosity suitable for the formation of a cured product and a sufficient rapid curing property. Therefore, it can be suitably applied to various uses.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J011 AA05 PA03 PB25 QA03 QA04                       QA07 QA13 QA14 QA17 QA23                       QA34 QA37 QA39 RA03 RA10                       RA11 RA15 SA01 SA04 SA06                       SA14 SA15 SA16 SA18 SA19                       TA03 UA01 UA03                 4J026 AA61 AB20 AC33 AC35 BA28                       BA30 BB01 DB06 DB08 DB36                       GA06 GA07

Claims (4)

[Claims] 1. An active energy ray-curable aqueous composition comprising a water-soluble acetophenone-based polymerization initiator, a water-soluble polymerizable compound, a water-soluble tertiary amine compound and water. 2. The active energy ray-curable aqueous composition according to claim 1, further comprising a water-soluble polymer. 3. The active energy ray-curable aqueous composition according to claim 1, further comprising a colorant. 4. The active energy ray-curable aqueous composition according to claim 2 or 3, wherein the water-soluble polymer is a polyvinylpyrrolidone homopolymer and / or a polyvinylpyrrolidone copolymer.