JP2003252979A - Cationically polymerizable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique which ensures long-term preservation stability without hindering curability of a cationically polymerizable compound and moreover is favorable from environmental and hygienic standpoints of view. <P>SOLUTION: The cationically polymerizable composition obtained by incorporating a cation polymerization initiator into the cationically polymerizable compound is caused to further contain water and, if desired, a water evaporation-preventing agent. Preferably, the cationically polymerizable compound comprises an alicyclic epoxy compound and an oxetane compound. The amount of water is preferably at least 1 wt.%, more preferably at least 2 wt.% based on the whole amount of the cationically polymerizable composition. The amount of the cation polymerization initiator is preferably 0.1-20 pts.wt. based on 100 pts.wt. of the cationically polymerizable compound. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cationically polymerizable composition having excellent storage stability and curability.

[0002]

2. Description of the Related Art As a quick-drying printing ink, an ink composition which is radically polymerized and cured by irradiation with active energy rays such as ultraviolet rays has been conventionally known. Such an ink composition has a problem that it is hardened in the presence of oxygen.

Therefore, in recent years, an ink composition has been proposed which is cationically polymerized and cured by irradiation with active energy rays. As such an ink composition, there has been already proposed a composition comprising an oxetane compound, a photocationic polymerization initiator, and a pigment, and optionally an epoxy compound added (JP-A-8-143806). Cationic polymerization is initiated by the presence of cations generated from the cationic polymerization initiator by irradiation with ultraviolet rays and the like, so that the polymerization is not inhibited by oxygen, and there is no particular limitation that it should be carried out in an inert atmosphere. However, it has the advantage that rapid and complete polymerization can be carried out in air.

However, if a cationic polymerization initiator is added to a cationically polymerizable compound such as an oxetane compound or an epoxy compound and stored for a long period of time, cations spontaneously generate from the cationic polymerization initiator even when the ultraviolet rays are blocked. However, there is a problem in that the cation initiates the polymerization of the cationically polymerizable compound to cause thickening and gelation.

In order to solve such problems, a composition containing a cationic polymerization catalyst and a cationically polymerizable organic material as essential components, a guanidine compound, a thiazole compound,
By adding one or more of a benzothiazole compound, a thiazolecarboxylic acid compound, a sulfenamide compound, a thiourea compound, an imidazole compound, a benzimidazole compound, and an alkylphenyl sulfide compound, the composition It has already been proposed to improve room temperature stability (pot life) of a product (see Japanese Patent Laid-Open No. 8-283320).

Further, a basic compound is added to the oxetane compound,
For example, basic inorganic compounds such as hydroxides, carbonates and alcoholates of alkali metals and alkaline earth metals,
It has already been proposed to add a basic organic compound such as an amine or other nitrogen-containing basic compound to improve the storage stability without impairing the ring-opening polymerizability of the oxetane compound (Japanese Patent Laid-Open No. 2000-186079). Bulletin,
See Japanese Patent Laid-Open No. 2000-327672).

[0007]

However, when the cationic polymerization initiator is added to the cationically polymerizable compound, the addition of the basic compound does not sufficiently improve the storage stability. In particular, when the cationically polymerizable compound is a mixed system of an oxetane compound and an alicyclic epoxy compound, the reactivity in the presence of the cationic polymerization initiator is much higher than that of the oxetane compound alone, and thus gelation is sufficiently caused. The effect of improving storage stability was not obtained.

If the amount of the guanidine compound or the like or the basic compound added is increased to solve such a problem, the problem of gelation of the cationically polymerizable compound is solved, but on the other hand, the curability It is difficult to satisfy both storage stability and curability at the same time. Further, some of the above-mentioned guanidine compounds and the above-mentioned basic compounds are harmful substances, and it is not preferable for the environment and hygiene to incorporate a large amount of such harmful substances in the composition.

The present invention can provide long-term storage stability without impairing the curability of a cationically polymerizable compound containing a cationic polymerization initiator, and further provide a technique which is preferable in terms of environment and hygiene. To aim.

[0010]

According to one aspect of the present invention, a cationically polymerizable composition in which a cationically polymerizable compound is contained in a cationically polymerizable compound further contains water. A cationically polymerizable composition is provided.

Further, according to another aspect of the present invention, water is added to a cationically polymerizable composition obtained by adding a cationic polymerization initiator to the cationically polymerizable compound. A method of stabilizing is provided.

The cationically polymerizable composition of the present invention is provided in the form of a one-component active energy ray-curable or heat-curable composition which is a solventless system comprising a cationically polymerizable compound, a cationic polymerization initiator and water. it can. When the composition is irradiated with an active energy ray, the cation is generated from the cationic polymerization initiator, and the action of the cation initiates the polymerization of the cationically polymerizable compound to cure the composition. During storage, water exists as an electron donor in the composition, and therefore, when a cation is generated from the cationic polymerization initiator, it traps the cation to function as a polymerization inhibitor and suppresses gelation of the composition. Enables stable storage. This cation trapping effect improves as the amount of water added increases. Therefore,
The composition of the present invention may contain a desired amount of water as long as the form of the solventless composition is not impaired. Since water is harmless, increasing the content in the composition does not cause environmental and hygiene inconveniences. Further, the water contained in the composition, during curing, is evaporated from the composition by the heat accompanying the irradiation of active energy rays, so that the curability of the composition is not impaired, and in particular,
When a thin film or a printed image is formed with the composition, water is evaporated and removed more quickly, which is convenient.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As the cationically polymerizable compound,
Examples thereof include cationically polymerizable vinyl compounds, lactones and cyclic ethers. Examples of the cationically polymerizable vinyl compound include styrene and vinyl ether. Examples of cyclic ethers include epoxy compounds and oxetane compounds, as well as spiroorthoesters, bicycloorthoesters, cyclic carbonates and the like.

The epoxy compound means a compound having an oxirane group which is a three-membered ring represented by the following formula (1),
Aromatic epoxy compounds and alicyclic epoxy compounds are included.

[0015]

[Chemical 1]

The oxetane compound means a compound having an oxetane ring which is a four-membered ring ether represented by the following formula (2).

[0017]

[Chemical 2]

Preferred cationically polymerizable compounds are cyclic ethers which undergo ring-opening polymerization by the action of cations, and more preferred are alicyclic epoxy compounds and oxetane compounds. Furthermore, since it has excellent curability,
It is particularly preferable to use the alicyclic epoxy compound and the oxetane compound as a mixture. In this case, the mixing ratio of the alicyclic epoxy compound and the oxetane compound (alicyclic epoxy compound / oxetane compound) is usually 5 by weight.
/ 95 to 95/5, preferably 10/90 to 50/50
It is said that If the amount of oxetane is too small, the cured product tends to have reduced flexibility and solvent resistance. On the other hand, if the amount of oxetane is too large, the risk of curing failure in a humid environment increases.

Preferred oxetane compounds are 3-
Ethyl-3-hydroxymethyl oxetane, 1,4 bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3- (phenoxymethyl)
Examples include oxetanes such as oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and di [1-ethyl (3-oxetanyl)] methyl ether.

Preferred alicyclic epoxy compounds include:
3,4-epoxycyclohexylmethyl-3 ', 4'-
Epoxy cyclohexane carboxylate (trade name UV
R6105, UVR6110 and CELLOXIDE
2021 available on the market), bis (3,4-epoxycyclohexylmethyl) adipate (product name UVR612
8), vinyl cyclohexene monoepoxide (trade name CELOXIDE2000 commercially available), ε-caprolactone-modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarboxylate (trade name CELOXIDE2081 commercially available) ), 1-methyl-4- (2-methyloxiranyl) -7-oxabicyclo [4,1,0] heptane (commercially available under the trade name CELOXIDE 3000), and the like. The UVR6105,
Both commercial products having the trade names of UVR6110 and UVR6128 are available from Union Carbide. The CELLOXIDE2000, CELLOXID
E2021, CELOXIDE2081 and CELO
All commercially available products having the trade name of XIDE3000 are available from Daicel Chemical Industries, Ltd. In addition, UVR6
105 is a low viscosity product of UVR6110.

Specific examples of the cationically polymerizable compound include:
JP-A-8-143806, JP-A-8-28332
No. 0, JP 2000-186079 A, JP 2
It is described in further detail in, for example, JP-A-000-327672, and the present invention can be carried out by appropriately selecting from the compounds exemplified therein.

Examples of the cationic polymerization initiator include known sulfonium salts and ammonium salts, as well as diaryl iodonium salts and triaryl sulfonium salts. JP-A-8-143806, JP-A-8-283
It can be appropriately selected and used from those described in Japanese Patent Publication No. 320, etc. As the cationic polymerization initiator, a commercially available product can be used as it is. As typical examples of commercially available products, trade names CI-1370, CI-2064, CI-2
397, CI-2624, CI-2639, CI-27
34, CI-2758, CI-2823, CI-285
5 and CI-5102 commercially available products (both manufactured by Nippon Soda Co., Ltd.), product name PHOTOINIT
Commercial products (made by Rhodia) available under IATOR 2047, trade names UVI-6974 and UVI-69.
Commercially available products (all manufactured by Union Carbite Co., Ltd.) can be listed under 90.

The amount of the cationic polymerization initiator used varies depending on the type, the type and amount ratio of the cationically polymerizable compound used, the use conditions, etc., but in practice, it is added to 100 parts by weight of the cationically polymerizable compound in the composition. On the other hand, usually 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight,
It is more preferably 3 to 5 parts by weight. When the amount of the cationic polymerization initiator is large, the polymerization proceeds rapidly, but the storage stability tends to be impaired, and when the amount is small, the curability is poor.

In the present invention, the content of water in the composition varies depending on the kind and ratio of cationically polymerizable compounds, the kind and ratio of cationic polymerization initiators, storage conditions, curing conditions, etc. Practically 1% by weight or more, preferably 2% by weight, based on the total amount of the composition.
That is all. If the water content is insufficient, the storage stability of the cationically polymerizable compound cannot be sufficiently improved.

In the present invention, as long as the morphology of the solvent-free composition is not impaired, it does not prevent excessive addition of water to the composition, but water is dissolved in the cationically polymerizable compound. Is preferred. Therefore, the upper limit of the water content is usually determined by the amount of water dissolved in the cationically polymerizable composition, and cannot be specified unconditionally,
Practically, usually 1 relative to the total amount of the cationically polymerizable composition.
The amount is 0% by weight or less, preferably 6% by weight or less, and more preferably 4% by weight or less. The amount of water added is determined in consideration of the amount of wear due to evaporation during storage and curing, but if the content of water becomes excessive, it will take a long time to cure the cationically polymerizable compound, and Water may precipitate in a low temperature environment.

Further, in the present invention, a water evaporation inhibitor may be contained in the composition. The water contained in the composition tends to wear due to evaporation during storage, and the storage stability of the composition tends to decrease over time. However, since the water evaporation is prevented by using the water evaporation inhibitor together, the storage stability of the composition can be maintained for a long period of time. The use of water evaporation inhibitors is preferred not only when the composition is stored in a closed system, but especially when it is stored in an open system such as an ink vehicle. As the water evaporation inhibitor, for example, ethylene glycol, triethylene glycol, dipropylene glycol, butylene glycol, polyethylene glycol (molecular weight 200
~ 600), glycerin, sorbitol, sodium lactate, sodium 2-pyrrolidone-5-carboxylate, sodium hyaluronate, and other substances having a moisturizing action such as alcohols, sugars and glycol ethers can be used.

The amount of the water evaporation inhibitor to be used can be appropriately adjusted depending on the kind of the cationically polymerizable compound, the kind of the water evaporation inhibitor, the storage condition, the desired storage period, etc., but it is contained in the composition. Practically 10 for water
˜200% by weight, preferably 50 to 100% by weight.

The cationically polymerizable composition of the present invention can be produced by sufficiently mixing the cationically polymerizable compound, the cationic polymerization initiator and water. In addition, it is possible to stabilize the composition by adding water to an existing cationically polymerizable composition in which the cationically polymerizable compound contains a cationic polymerization initiator and mixing them sufficiently.

The viscosity of the cationically polymerizable composition of the present invention is
It can be appropriately adjusted by selecting the molecular weight and combination of the cationically polymerizable compounds according to the use of the composition. In particular, when the composition of the present invention is used as a vehicle for an ultraviolet curable ink for an industrial inkjet printer, the viscosity at 23 ° C. is adjusted to 5 to 50 mPa · s, preferably 10 to 30 mPa · s. To be done.

The cationically polymerizable composition of the present invention can be cured by initiating a polymerization reaction by active energy rays such as ultraviolet rays, X-rays and electron rays and heating as in a conventional method. If desired, various additives such as pigments, dyes, sensitizers, flame retardants and antistatic agents can be added to the composition of the present invention. For example, ink, vehicle,
Gloss varnish, paint, adhesive, prepreg, sealing material,
It is preferably used for laminated plates and molding materials.

[0031]

EXAMPLES The present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. The test method for the composition was as follows.

[Storage stability test] A state in which the composition is put in a container with a lid (closed system) and a state without a lid (open system).
After being subjected to an accelerated test in a high temperature environment of about 60 ° C. for 1 month, the state of the composition was visually evaluated. The evaluation was based on the following criteria. Storage stability evaluation criteria: A: Gelation of the composition was not observed in either the closed system or the open system. ◯: Gelation of the composition was not observed in the closed system. X: Gelation of the composition was observed in both the open system and the closed system.

[Curing Test] A thin film (thickness: 10 μm) of the composition was formed on one surface of a polyethylene terephthalate (PET) film. The resulting film was passed under an 80 watt high pressure mercury lamp at a belt speed of 20 meters per minute to irradiate the thin film with ultraviolet light. Immediately after the irradiation, the thin film was touched with a finger to evaluate the presence or absence of curing according to the following criteria. Curability evaluation criteria: ◯: Cured. X: Does not cure.

[Measurement of Viscosity] The viscosity of the composition was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at a temperature of 23 ° C. and a rotation speed of 1
It was measured under the condition of 0 rpm.

[Measurement of Water Content in Composition] Immediately after the composition was prepared, the water content of the composition (water content (wt%) in the total amount of the composition) was measured with a measurement kit manufactured by Metrohm. It was used and measured by the Karl Fischer method. The measured water content was rounded off to one decimal place.

[Discharge performance test]
ar) ink-jet printer heads were used for evaluation, and evaluation was performed according to the following criteria. Discharge performance evaluation criteria: ◯: Discharges smoothly. Δ: Slightly lacking in smoothness, but ejection is possible. X: Discharge is impossible.

Examples 1 to 8 According to the formulations shown in Table 1, an alicyclic epoxy compound, an oxetane compound, a cationic polymerization initiator, water, and, if necessary, a water evaporation inhibitor were sufficiently mixed, and cationic polymerization was performed. A sex composition was prepared. The obtained composition was subjected to the tests and measurements described above and evaluated. The results are shown in Table 1. The amount of the cationic polymerization initiator added was 10 parts by weight for the storage stability test and 3 parts by weight for the other tests and measurements.

Comparative Example 1 A composition was obtained in the same manner as in Example 1 except that water was not added. The obtained composition was subjected to the tests and measurements described above and evaluated. The results are shown in Table 1.

Comparative Example 2 A composition was obtained in the same manner as in Example 2 except that water was not added. The obtained composition was subjected to the tests and measurements described above and evaluated. The results are shown in Table 1.

Comparative Examples 3 to 5 0.1 parts by weight of triethanolamine in place of water, 0.5
A composition was obtained in the same manner as in Example 1 except that 1 part by weight or 1 part by weight was added. The obtained composition was subjected to the tests and measurements described above and evaluated. The results are shown in Table 1.

Comparative Examples 6 to 7 Compositions were obtained in the same manner as in Example 1 except that 0.1 part by weight or 1 part by weight of 1,3-phenylguanidine was added instead of water. The obtained composition was subjected to the tests and measurements described above and evaluated. The results are shown in Table 1.

[0042]

[Table 1]

The symbols in Table 1 mean the following. CELOXIDE 3000: 1-methyl-4- (2-
Methyloxiranyl) -7-oxabicyclo [4,1,
0] heptane (CELOXI manufactured by Daicel Chemical Industries, Ltd.
DE3000 (trade name)). UVR6105: 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarboxylate (manufactured by Union Carbide Co., UVR6105
(Product name)). OXT221: Di [1-ethyl (3-oxetanyl)]
Methyl ether (TOA Gosei Co., Ltd., OXT221
(Product name)). OXT121: 1,4 bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene (TOA Gosei Co., Ltd., OXT121 (trade name)). UVI6990: Sulfonium salt-based cationic polymerization initiator (Cyracure (registered trademark) manufactured by Union Carbide Co., Ltd.
Photocuring initiator UVI-6990 (trade name). TEG: triethylene glycol. PEG: polyethylene glycol (molecular weight: 200). TEA: triethanolamine. PhGu: 1,3-phenylguanidine.

Comparison between Example 1 and Comparative Example 1 and Example 2
From the comparison with Comparative Example 2, it can be seen that the addition of water to the cationically polymerizable composition improves the storage stability without impairing the curability. Further, by comparing Comparative Examples 3 to 7 with Examples 1 and 3, in the case of amines and guanidine compounds conventionally proposed as stabilizers, both storage stability and curability cannot be achieved at the same time. On the other hand, according to the present invention, it can be seen that both can be compatible. From Examples 4 and 5, it is understood that the combined use of water and the water evaporation inhibitor significantly improves the storage stability. By selecting the type and formulation of the cationically polymerizable compound used in combination from Examples 6 to 8, the viscosity of the composition can be adjusted, and the ejection performance and good storage stability that can be used as a vehicle for commercial inkjet inks And that it is possible to provide a composition having curability.

[0045]

EFFECTS OF THE INVENTION According to the present invention, water is added to a cationically polymerizable composition, particularly a cationically polymerizable composition in which an oxetane compound and an alicyclic epoxy compound are used in combination. The storage stability is remarkably improved while maintaining the property, and it can be used not only for storage in a closed system but also for storage or use in an open system. A composition is provided.

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Claims (7)

[Claims] 1. A cationically polymerizable composition comprising a cationically polymerizable compound and a cationic polymerization initiator, wherein the cationically polymerizable composition further contains water. 2. The cationically polymerizable composition according to claim 1, wherein the cationically polymerizable compound comprises an alicyclic epoxy compound and an oxetane compound. 3. The cationically polymerizable composition according to claim 1, which contains 1% by weight or more of water with respect to the total amount of the cationically polymerizable composition. 4. A cationic polymerization initiator is contained in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the cationically polymerizable compound,
1 to 10% by weight of water based on the total amount of the cationically polymerizable composition
The cationically polymerizable composition according to claim 1 or 2, further comprising: 5. The method according to claim 1, further comprising a water evaporation inhibitor.
5. The cationically polymerizable composition according to any one of items 1 to 4. 6. The viscosity at 23 ° C. is 5 mPa · s-5.
It is 0 mPa * s, The cationically polymerizable composition of any one of Claim 1 thru | or 5 characterized by the above-mentioned. 7. A method for stabilizing a cationically polymerizable composition, which comprises adding water to the cationically polymerizable composition comprising a cationically polymerizable compound containing a cationic polymerization initiator.