JP2590682B2 - Active energy ray-curable water-containing resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active energy ray-curable water-containing resin composition.

[0002]

2. Description of the Related Art Active energy ray-curable resin compositions are
In addition to being excellent in safety because it does not contain a solvent, it is generally recognized as having excellent characteristics in terms of productivity and energy saving because of its excellent curability. Active energy ray-curable resin compositions, in view of such properties, overcoating agents for various plastic films, paints for woodworking,
It is used as an active ingredient in various coatings such as printing inks and adhesives.

[0003] In the above applications, particularly when the viscosity of the product is required to be reduced, a convenient method such as using a large amount of a reactive diluent or using an organic solvent in combination is usually adopted. However, when a large amount of the reactive diluent is used, problems such as skin irritation and deterioration in curability are likely to occur, and when an organic solvent is used in combination, the risk of air pollution and fire increases.

[0004] Therefore, in recent years, there has been a growing demand for water-based compositions from the viewpoints of air pollution prevention, regulations under the Fire Service Law, occupational safety and health, and the like. Various aqueous active energy ray-curable resin compositions have already been developed. However, the skeleton of the vehicle resin used for them contains (meth)
Since there are relatively many ester sites derived from acrylic acid esters, hydrolysis and performance degradation may occur over time, and gelation may occur during product storage,
At present, satisfactory characteristics have not yet been achieved.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances regarding an aqueous active energy ray-curable resin composition,
Aqueous active energy ray-curable resin composition having curability and water resistance comparable to non-aqueous active energy ray-curable resin compositions, relatively low viscosity, low skin irritation and excellent storage stability The purpose is to obtain things.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have focused on the vehicle components in the composition, and conducted intensive studies on the types of the components and their usage ratios. It has been found that by selecting the following specific components as a vehicle, an excellent aqueous active energy ray-curable resin composition that satisfies the above object can be obtained unexpectedly. The present invention has been completed based on such findings.

That is, the present invention relates to an active energy ray-curable water-containing resin composition comprising a vehicle and water as essential components, wherein the vehicle comprises (A) an acrylate ester containing at least one hydroxyl group in a molecule; The present invention relates to an active energy ray-curable water-containing resin composition, which is a reaction product comprising an organic polyisocyanate and (C) a polyethylene glycol monoalkyl ether containing one hydroxyl group.

The vehicle in the active energy ray-curable water-containing resin composition of the present invention is a reaction product composed of the components (A), (B) and (C) as described above.
The component (A) is a hydroxyl group-containing acrylic ester, and includes various types having at least one hydroxyl group and at least one (meth) acryloyl group in the molecule. Specific examples include 2-hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate. And 2-aralkyloxypropyl (meth) acrylates such as 4-hydroxybutyl (meth) acrylate and 2-phenoxypropyl (meth) acrylate, and pentaerythritol triacrylate. These can be used alone or in combination. The amount of the component (A) is usually 25 to 70% by weight, preferably 30 to 65% by weight, based on the sum of the components (A) and (B) in the vehicle. When a polyol polyacrylate such as polyepoxy acrylate is used, the viscosity of the obtained product tends to increase.

The component (B), which is an organic polyisocyanate, includes an organic polyisocyanate having three or more reactive isocyanate groups in the molecule. The molecular weight is preferably about 500 to 1,000. (B)
Specific examples of the component include, for example, trimers obtained from various diisocyanates such as 1,6-hexane diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and dimethyl isomers. Examples thereof include a prepolymer reacted with a polyhydric alcohol such as propane, and polymethylene polyphenyl polyisocyanate.
The amount of the component (B) used is usually 30 to 75% by weight, preferably 35 to 70% by weight, based on the sum of the components (A) and (B) in the vehicle.

As the polyethylene glycol monoalkyl ether of the component (C), various types having one hydroxyl group in the molecule can be used without any particular limitation, and those represented by the following general formula (1) are particularly preferable. It is.

H— (OCH ₂ CH ₂ ) _n —OR (1) (wherein R represents a lower alkyl group and n represents an integer of 3 to 25). The amount of the component (C) used in the vehicle is as follows: ,Normally,
(C) / {(A) + (B)} = 0.2 to 0.6, preferably 0.25 to 0.4. When the ratio is less than 0.2, the water-containing resin composition itself has poor water dispersibility, and tends to separate over time even if the initial water dispersibility is relatively good. There is
Not preferred. On the other hand, if it exceeds 0.6, the curing becomes insufficient due to a decrease in the crosslink density, or even if the curing is sufficiently performed, the water resistance of the film tends to decrease, which is not preferable.

Hereinafter, a method for producing a vehicle comprising the components (A) to (C) will be described. First, the component (A) and the component (B)
The components are reacted in the above-mentioned proportions to obtain a prepolymer having a free isocyanate group. Next, the prepolymer is reacted with the component (C) at the above-mentioned ratio. The reaction temperature is 40 to 100 ° C, preferably 60 to 80 ° C, and the total reaction time is about 4 to 12 hours. In the urethanization reaction, a known urethanization catalyst such as stannous octylate is preferably used to promote the reaction. Further, in order to prevent polymerization of the component (A) during the urethanization reaction, hydroquinone, methoxyphenol,
Add a polymerization inhibitor such as phenothiazine to the reaction system
5,000 ppm, preferably 50-2000 ppm, or air sealing may be performed.

The reaction product obtained above can be easily formed into the active energy ray-curable water-containing resin composition of the present invention by dispersing in water according to various known methods. Specifically, water is gradually added while the reaction product is vigorously stirred to adjust the solid content to about 20 to 50% by weight. The temperature in the system at the time of dispersion is usually from 40 to 100 ° C., preferably from 60 to 80 ° C. After completion of the dispersion, the system can be cooled to obtain the desired hydrous resin composition. In the dispersing step, the above-mentioned operation for preventing the polymerization of the component (A) can be carried out if necessary.

As described above, the active energy ray-curable water-containing resin composition of the present invention comprises the above-mentioned (A), (B) and (C).
It is an oil-in-water emulsion obtained by forcibly emulsifying and dispersing a reaction product composed of components in water. The water content in the composition is not particularly limited, but is determined in consideration of the workability, viscosity and the like of the obtained composition, and is usually in the range of 60 to 900 parts by weight per 100 parts by weight of the vehicle. Although the composition does not substantially contain a reactive diluent for the purpose of reducing skin irritation, conventionally known reactive diluents do not adversely affect skin irritation or the stability of the water-containing resin composition. It does not prevent the use of a small amount of the agent.

In the active energy ray-curable water-containing resin composition of the present invention, in addition to the essential components of vehicle and water, a hydrophilic solvent such as a lower alcohol, a coloring agent, a photoinitiator, Additives such as a leveling improver may be appropriately used within a range not departing from the purpose and effect of the present invention. Since the water-containing resin composition of the present invention itself has good standing stability, it is not necessary to add a surfactant, and therefore, the water resistance of the cured film is good, and particularly, the film whitening phenomenon during immersion is prevented. be able to.

The optimum viscosity of the active-energy-ray-curable water-containing resin composition of the present invention cannot be uniquely determined because it varies depending on the application, but it is usually preferably about 2 to 500 cP / 25 ° C.

The active energy ray-curable water-containing resin composition of the present invention obtained as described above has excellent curability and water resistance, and has relatively low viscosity and good stability over time. Various applications in which known non-aqueous active energy ray-curable resin compositions have been used, for example, various coating films such as overcoating agents for plastic films, paints for woodworking, electrodeposition paints, printing inks, paper quality improvers, and the like. Can be applied to a laminating adhesive for paper or plastic film substrates. Further, it can be suitably used as an auxiliary for improving the aqueous dispersion stability of other active energy ray-curable resin compositions.

[0018]

According to the present invention, the resin composition has curability and water resistance comparable to those of the non-aqueous active energy ray-curable resin composition, and has relatively low viscosity, low skin irritation and good An aqueous active energy ray-curable resin composition having aging stability can be provided.

[0019]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" are based on weight unless otherwise specified.

Example 1 In a flask equipped with a stirrer, a thermometer, an air blowing tube and a reflux condenser, 343.5 parts of HMDI trimer (trade name: Coronate HX, manufactured by Nippon Polyurethane Co., Ltd.), hydroxypropyl acrylate 166.3 parts, 0.7 parts of 4-methoxyphenol and 0.007 parts of a polymerization inhibitor (trade name: Q-1301, manufactured by Wako Pure Chemical Industries, Ltd.) were charged. Then, while stirring and blowing in air, 0.14 parts of stannous octylate was charged, the temperature of the system was raised to 75 to 80 ° C., and the temperature was maintained for 1.5 hours, and then polyethylene glycol monomethyl ether (trade name, manufactured by Toho Chemical Industry Co., Ltd. Methoxy PEG
# 400) 190.3 parts were added, and the remaining isocyanate groups in the HMDI trimer were reacted with the hydroxyl groups in polyethylene glycol monomethyl ether. 80 parts of the obtained polyurethane acrylate was kept at 60 to 70 ° C., and 120 parts of deionized water was added and dispersed with stirring to obtain an emulsion having a nonvolatile content of 40%. Table 1 shows the proportions of each component of the polyurethane acrylate, the viscosity of the emulsion at 25 ° C., and the stability after being left at room temperature for one month (the same applies hereinafter).

Example 2 In the same flask as in Example 1, HMDI trimer 249.
1 part, hydroxypropyl acrylate 32.9 parts, pentaerythritol triacrylate 280.0 parts, 4
-0.7 parts of methoxyphenol and 0.007 parts of the polymerization inhibitor (Q-1301) were charged. Then, while performing air blowing and stirring, stannous octoate 0.1
After charging 4 parts of the system and raising the temperature to 75 to 80 ° C. and keeping the temperature for 1.5 hours, 138.0 parts of methoxy PEG # 400 was added and reacted. The obtained urethane acrylate was dispersed in water in the same manner as in Example 1 to obtain an emulsion having a nonvolatile content of 40%.

Example 3 In the same flask as in Example 1, HMDI trimer 225.
8 parts, pentaerythritol triacrylate 349.
1 part, 0.7 part of 4-methoxyphenol and 0.007 part of the polymerization inhibitor (Q-1301) were charged. Then, while performing air blowing and stirring, 0.14 parts of stannous octoate was charged, and the inside of the system was heated to 75 to 80 ° C.
After incubation for 5 hours, methoxy PEG # 400 125.
One part was added and allowed to react. The obtained urethane acrylate was dispersed in water in the same manner as in Example 1 to obtain a nonvolatile matter 40%.
% Emulsion was obtained.

Example 4 In the same flask as in Example 1, HMDI trimer 235.
3 parts, pentaerythritol triacrylate 363.
7 parts, 4-methoxyphenol 0.7 parts and the polymerization inhibitor (Q-1301) 0.007 parts were charged. Then, while performing air blowing and stirring, 0.14 parts of stannous octoate was charged, and the inside of the system was heated to 75 to 80 ° C.
After keeping it warm for 5 hours, polyethylene glycol monomethyl ether (trade name: Methoxy PEG # 1 manufactured by Toho Chemical Industry Co., Ltd.)
000) 138.3 parts and methoxy PEG # 400
55.1 parts were added and reacted. The obtained urethane acrylate was dispersed in water in the same manner as in Example 1 to obtain an emulsion having a nonvolatile content of 40%.

Example 5 In the same flask as in Example 1, HMDI trimer 235.
3 parts, pentaerythritol triacrylate 363.
7 parts, 4-methoxyphenol 0.7 parts and the polymerization inhibitor (Q-1301) 0.007 parts were charged. Then, while performing air blowing and stirring, 0.14 parts of stannous octoate was charged, and the inside of the system was heated to 75 to 80 ° C.
After keeping it warm for 5 hours, polyethylene glycol monomethyl ether (trade name: Methoxy PEG # 2, manufactured by Toho Chemical Industry Co., Ltd.)
25) 35.8 parts and methoxy PEG # 400 6
5.2 parts were added and reacted. The obtained urethane acrylate was dispersed in water in the same manner as in Example 1 to obtain an emulsion having a nonvolatile content of 40%.

(Curing Test) Varnish preparation and curing test of the varnish were carried out on the emulsions (active-energy-ray-curable resin-containing composition) obtained in Examples 1 to 5 under the following conditions, and their film properties were evaluated. Was evaluated. Table 2 shows the evaluation results.

Preparation of varnish: The above emulsion and a photoinitiator (trade name: Irgacure 184, manufactured by Ciba-Geigy Co., Ltd.) at 5% of the solid content were stirred and mixed until uniform. Curability: The varnish was coated on an ABS plate to a thickness of 5 μm, dried with hot air at 80 ° C. for 1 minute, and then irradiated with ultraviolet light from a high-pressure mercury lamp of 80 W / cm until the film became tack-free. It was evaluated in terms of energy (mJ). Preparation of cured film: In the evaluation of pencil hardness, solvent resistance, and water resistance, a cured film obtained by preparing the same dry film and irradiating the film with 100 mJ of ultraviolet light to cure the film was used. Pencil hardness: according to JIS-K-5400. Solvent resistance: After the cured film was left in MEK for 24 hours, changes in appearance were visually observed. Water resistance: After the cured film was left in deionized water for 24 hours, changes in appearance were visually observed.

[0027]

[Table 1]

[0028]

[Table 2]

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Satoshi Nagano Examiner, Yoshiaki Matsui, Arakawa Chemical Industry Co., Ltd. Research Institute 1-1-1 Tsurumi, Tsurumi-ku, Osaka (56) References JP-A-2-245015 ( JP, A) JP-A-4-15212 (JP, A) JP-A-5-320299 (JP, A)

Claims (3)

(57) [Claims] 1. An active energy ray-curable water-containing resin composition comprising a vehicle and water as essential components, wherein the vehicle comprises (A) an acrylate ester containing at least one hydroxyl group in a molecule, and (B) an organic polymer. An active energy ray-curable water-containing resin composition, which is a reaction product comprising an isocyanate and (C) a polyethylene glycol monoalkyl ether containing one hydroxyl group. 2. In the vehicle, (C) is a compound represented by the following general formula (1): H- (OCH ₂ CH ₂ ) _n -OR
(1) The active energy ray-curable water-containing resin composition according to claim 1, wherein R is a lower alkyl group and n is an integer of 3 to 25. 3. The use ratio of each component in the vehicle is (A) :( B) = 25 to 70:30 to 75 (% by weight), and (C) / ｛(A) + (B) )｝ = 0.2
The active energy ray-curable water-containing resin composition according to claim 1, which satisfies the condition of -0.6.