JP2003192745A - Ultraviolet-curing composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet-curing composition which is excellent in compatibility and transparency, has a relatively small volume shrinkage on curing, and gives a cured material reduced in stress on curing. <P>SOLUTION: The ultraviolet-curing composition comprises essentially a polyester acrylate (A) having three or more (meth)acryloyl groups on average in the molecule, a conjugated diene polymer (B) having one or more (meth)acryloyl groups on average in the molecule, a (meth)acrylic monomer (C) and a photo- initiator (D). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet curable composition. The UV-curable composition of the present invention is excellent in compatibility and transparency, and has a relatively small volume shrinkage upon curing, and is useful for applications such as adhesives and coating agents.

[0002]

2. Description of the Related Art Polyester acrylate resin, which is one of the typical UV curable resins, is photocurable, heat resistant, and
It has excellent properties such as chemical resistance, and has traditionally been used as a coating material for wood-based materials such as wood furniture, printing ink for paper or metal containers, coating resin and sealing material for electronic parts, and plastic materials. It has been used or developed for various purposes such as a hard coat.

[0003]

However, it is generally known that a polymer such as a polyester acrylate resin is accompanied by a relatively large volume shrinkage upon photo-curing, such as an adhesive, a coating agent or a molded article. In the field of (2), there is a problem that in applications requiring precision, a large stress is applied at the time of curing, which may cause cracking or peeling of the cured product. Therefore, an object of the present invention is to provide an ultraviolet curable composition having a relatively small volume shrinkage during curing and a reduced stress during curing, and having excellent compatibility and transparency.

[0004]

According to the present invention, the above object is to provide a polyester acrylate (A) having an average of three or more (meth) acryloyl groups per molecule, and one molecule of (meth) acryloyl group. A conjugated diene-based polymer (B) having an average of 1 or more per unit,
(Meth) acrylic monomer (C) and photoinitiator (D)
This is achieved by providing an ultraviolet curable composition containing as an essential component.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A polyester acrylate (hereinafter, referred to as polyester acrylate (A)) having 3 or more (meth) acryloyl groups used as the component (A) in the ultraviolet curable composition of the present invention on average per molecule. May be abbreviated) means, for example, that the hydroxyl groups of a polyester polyol composed of a polyhydric alcohol and a polybasic acid and having an average of three or more hydroxyl groups per molecule are reacted with a (meth) acrylic acid halide or the like. Then, it can be produced by introducing 3 or more (meth) acryloyl groups on average per molecule. Here, as the polyhydric alcohol constituting the polyester polyol having an average of three or more hydroxyl groups per molecule, for example, ethylene glycol, propylene glycol, butanediol, hexanediol, nonanediol, 3-methylpentanediol, neo Pentyl glycol, decanediol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, cyclohexanedimethanol, glycerin,
Examples thereof include trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, an ethylene oxide adduct of trimethylolpropane, and a propylene oxide adduct of trimethylolpropane. On the other hand, as the polybasic acid, succinic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid, suberic acid, decanedicarboxylic acid, tetrabromophthalic acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, pyrolic acid. Mellitic acid etc. can be mentioned.

The polyester acrylate (A) is also available as a commercial product, for example, manufactured by Toa Gosei Co., Ltd. under the trade names "Aronix M-8030", "Aronix M-8060" and "Aronix M-810".
0 ”,“ Aronix M-8530 ”,“ Aronix M-8560 ”and the like.

A conjugated diene-based polymer having an average of one or more (meth) acryloyl groups used as the component (B) in the ultraviolet-curable composition of the present invention per molecule (hereinafter, the conjugated diene-based polymer (B May be abbreviated as)), for example, after synthesizing a conjugated diene-based polymer first and then reacting the conjugated diene-based polymer with a dibasic unsaturated acid anhydride, the resulting polymer It can be obtained by reacting a part or all of the acid anhydride group of the above with a (meth) acrylic acid ester having a hydroxyl group in the ester moiety. As another method of obtaining the conjugated diene-based polymer (B), a conjugated diene-based polymer having a hydroxyl group and a (meth) acrylic acid ester having a hydroxyl group in the ester portion thereof may be used as a 2,4-tolylene diisocyanate compound. A method of reacting via a diisocyanate compound; a method of reacting a conjugated diene polymer having a carboxyl group with a (meth) acrylic acid ester having a glycidyl group in the ester moiety;
Examples thereof include a method of reacting a conjugated diene-based polymer having a hydroxyl group with a (meth) acrylic acid ester having an acid halide group in the ester portion.

Preferably, the conjugated diene polymer (B)
Is to first synthesize a conjugated diene-based polymer, and then to react this conjugated diene-based polymer with a dibasic unsaturated acid anhydride, and subsequently, a part or all of the acid anhydride groups in the obtained polymer. Can be obtained by reacting with a (meth) acrylic acid ester having a hydroxyl group in the ester moiety.

Examples of the conjugated diene compound which constitutes the conjugated diene-based polymer as the raw material of the conjugated diene-based polymer (B) include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-phenylbutadiene, 2-phenylbutadiene, 1,1-diphenylbutadiene, 1,2-diphenylbutadiene, 2,3
-Diphenyl butadiene etc. are mentioned. The conjugated diene-based polymer may be composed of one kind of these conjugated diene compounds alone, or may be composed of two or more kinds. As the conjugated diene-based polymer, polybutadiene, polyisoprene, or a copolymer of a mixture of isoprene and butadiene is particularly preferable.

The conjugated diene polymer used as the raw material is
Produced by anionic polymerization of the above-mentioned conjugated diene compounds such as butadiene and isoprene with sodium naphthalene complex, alkyl lithium such as n-butyl lithium, s-butyl lithium, methyl lithium, ethyl lithium and pentyl lithium as an initiator. It can also be produced by radical polymerization using an azobisnitrile compound such as azobisisobutyronitrile or a peroxide such as benzoyl peroxide as an initiator. In addition, these polymerization reactions are usually performed under the conditions of a polymerization temperature of −78 ° C. to 150 ° C. and a polymerization time of 1 to 100 hours in the presence of an aliphatic or aromatic hydrocarbon solvent such as hexane, heptane, toluene, and xylene. Can be done at.

The number average molecular weight of the conjugated diene polymer before introducing the acid anhydride group is not limited in a strict sense, but it is usually preferably in the range of 2,000 to 100,000. More preferably, it is in the range of 1,000 to 50,000. When the number average molecular weight is less than 2,000, the crosslinking density becomes high, and the rubber elasticity after curing of the obtained ultraviolet curable composition tends to be impaired. On the other hand, if the number average molecular weight exceeds 100,000, the viscosity of the conjugated diene-based polymer (B) obtained will be high and the workability will tend to be reduced, such being undesirable. In addition,
The number average molecular weight as used herein means the polystyrene equivalent number average molecular weight measured by gel permeation chromatography (GPC).

Next, an acid anhydride group is introduced into the conjugated diene polymer obtained by the above method by reacting it with a dibasic unsaturated acid anhydride. In this reaction, for example, a conjugated diene-based polymer and a dibasic unsaturated acid anhydride are mixed in the presence of a solvent inert to the reaction such as hexane, heptane, toluene, xylene and other aliphatic or aromatic hydrocarbon solvents. Alternatively, in the absence of the solvent, the reaction can usually be performed by stirring at room temperature to 200 ° C. for 0.1 to 100 hours.

As such a dibasic unsaturated acid anhydride, for example, maleic anhydride can be used. The amount of the dibasic unsaturated acid anhydride used is such that the conjugated diene polymer (B) finally produced has an amount of one or more (meth) acryloyl groups per molecule as the average. The upper limit is not particularly limited as long as it is an amount capable of introducing an anhydride group into the conjugated diene polymer, but is usually in the range of 0.1 to 200 parts by mass with respect to 100 parts by mass of the conjugated diene polymer. It is preferably present, and more preferably in the range of 1 to 150 parts by mass. The amount of the acid anhydride group introduced into the conjugated diene-based polymer is usually in the range of 1 to 30 as an average per molecule by reacting under the above-mentioned conditions.
It is preferable to control to a range of -20.

The amount of the acid anhydride group introduced into the conjugated diene polymer by the above reaction can be quantified by an analytical means such as NMR or neutralization titration.

Subsequently, a part or all of the acid anhydride groups introduced into the above conjugated diene-based polymer is reacted with a (meth) acrylic acid ester having a hydroxyl group in the ester moiety to give a conjugated diene-based polymer ( B) is obtained.

This reaction is carried out in the presence or absence of a solvent inert to the reaction such as an aliphatic or aromatic hydrocarbon solvent such as hexane, heptane, toluene or xylene.
Usually, it can be performed by stirring at room temperature to 200 ° C. for 0.1 to 100 hours.

Examples of the (meth) acrylic acid ester having a hydroxyl group in the ester moiety include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and penta. Examples thereof include erythritol triacrylate, pentaerythritol trimethacrylate, and dipentaerythritol monohydroxy acrylate. Among these, 2-hydroxyethyl acrylate, in terms of price and easy availability,
2-Hydroxyethyl methacrylate is preferred. The amount of the (meth) acrylic acid ester having a hydroxyl group in the ester portion must be such that the number of (meth) acryloyl groups in the conjugated diene polymer (B) is 1 or more as an average per molecule, Preferably 2-3
0, more preferably 3 to 20 (from the viewpoint, usually in the range of 0.01 to 1.5 mole times with respect to the acid anhydride group that the conjugated diene polymer has as an average per molecule thereof. It is more preferable that the conjugated diene polymer (B) has an average per molecule (meta).
If the number of acryloyl groups is less than 1, compatibility with the polyester acrylate (A) will be poor, while if it exceeds 30, the viscosity of the conjugated diene polymer (B) will be high, which is not preferable in terms of workability.

When a part of the acid anhydride group introduced into the conjugated diene-based polymer is reacted with a (meth) acrylic acid ester having a hydroxyl group in the ester part, the conjugated diene-based polymer (B) is obtained. Part of the acid anhydride group remains. When the ultraviolet curable composition of the present invention is prepared using this conjugated diene polymer (B), the acid anhydride group remaining in the composition and the moisture in the air gradually react depending on the storage state. Then, since the composition is cured, there may be a problem in storage stability. From this viewpoint, (meth) obtained by the above reaction, if necessary.
The acid anhydride group remaining in the conjugated diene-based polymer (B) having at least one acryloyl group can be converted into a carboxyl group and an ester group by further reacting with an alcohol compound. The alcohol compound is not particularly limited, and examples thereof include methanol, ethanol, n-isopropanol, butanol and the like. The amount of the alcohol compound used is not strictly limited, but when an acid anhydride group remains in the conjugated diene polymer (B), it is usually 1 to 2 mol based on the remaining acid anhydride group. It is preferably in the double range. When an acid anhydride group remains in the conjugated diene polymer (B), the reaction between the acid anhydride group and the alcohol compound is hexane,
In the presence or absence of a solvent inert to the reaction such as an aliphatic or aromatic hydrocarbon solvent such as heptane, toluene, xylene, etc., usually at room temperature to 200 ° C. for 0.1 to 10
It can be performed by stirring for 0 hours.

The conjugated diene polymer (B) used in the present invention is also available as a commercial product, for example,
RICON, product name "RIC-3500", "RI
C-3100 ", manufactured by Nippon Soda Co., Ltd., trade name" TE-200 "
0 ”and the like.

Components in the ultraviolet curable composition of the present invention
(Meth) acrylic monomer used as (C) (hereinafter
Below, it may be abbreviated as (meth) acrylic monomer (C).
There is, for example, methyl (meth) acrylate,
Ethyl (meth) acrylate, Isopropyl (meth) a
Acrylate, butyl (meth) acrylate, 2-ethyl
Hexyl (meth) acrylate, dodecyl (meth) ac
Relate, isododecyl (meth) acrylate, tride
Sil (meth) acrylate, stearyl (meth) acrylate
Rate, cyclohexyl (meth) acrylate, 2-hi
Droxyethyl (meth) acrylate, 2-hydroxy
Propyl (meth) acrylate, 2-hydroxybutyl
(Meth) acrylate, 4-hydroxybutyl (meth)
Acrylate, polyethylene glycol mono (meth) a
Crylate, polypropylene glycol mono (meth) a
Acrylate, phenyl (meth) acrylate, 2-hydr
Roxy-3-phenoxyethyl (meth) acrylate,
Benzyl (meth) acrylate, p-nonylphenyl
(Meth) acrylate, isobornyl (meth) acryl
, Dicyclopentenyl (meth) acrylate, tri
Cyclo [5,2,1,0 ^2,6] Decanyl (meta)
Relate, 2,2,6,6-tetramethylpiperidinyl
(Meth) acrylate, 1,2,2,6,6-pentame
Cylpiperidinyl (meth) acrylate, tetrahydro
Furfuryl (meth) acrylate, p-cumylphenyl
(Meth) acrylate, diethylaminoethyl (meth)
Acrylate, bisphenol A di (2-hydroxy-
3-acryloyloxypropyl), bisphenol A
Di (meth) acrylate or ethylene glycol of these
Modified product; butanediol di (meth) acrylate,
Hexanediol di (meth) acrylate, nonandio
Di- (meth) acrylate, polyethylene glycol
Di (meth) acrylate, polypropylene glycol di
(Meth) acrylate etc. are mentioned. Among these
Also, the (meth) acrylic monomer (C) is
It is preferable that the compound has no polar group other than the liloyl group.
More preferably, isobornyl (meth) acrylate, 1,9-
Nonanediol di (meth) acrylate, dicyclopen
Tenyl (meth) acrylate is particularly preferred.

The amount of the (meth) acrylic monomer (C) used is not strictly limited, but from the viewpoint of compatibility in the ultraviolet-curable composition of the present invention, the polyester acrylate (A) and the conjugated diene-based compound are used. Generally, the amount is preferably in the range of 10 to 300 parts by mass, more preferably 30 to 150 parts by mass, based on 100 parts by mass of the total amount of the polymer (B). The mixing ratio in the mixture of the polyester acrylate (A) and the conjugated diene polymer (B) is not particularly limited.

The photoinitiator used as the component (D) in the ultraviolet-curable composition of the present invention (hereinafter, photoinitiator (D))
May be abbreviated), for example, 2-hydroxy-2methyl-1-phenyl-propan-1-one [2
-Hydroxy-2-methylpropiophenone], 1-hydroxycyclohexyl phenyl ketone, bis (2,2
4,6-trimethylbenzoyl) phenylphosphine oxide, acetophenone, benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl, 2-chlorothioxanthone and the like can be mentioned. These may be used alone or in combination of two or more. The amount of the photoinitiator (D) used is not strictly limited, but from the viewpoint of improving the curability, the polyester acrylate (A), the conjugated diene polymer (B) and the (meth) acrylic monomer ( It is usually preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the mixture of C),
More preferably, it is in the range of 0.5 to 10 parts by mass. Further, for the purpose of improving photocurability, amines such as n-butylamine and triethylamine may be further added, if necessary. When the amines are added, the addition amount is usually 0.01 to 100 parts by mass based on 100 parts by mass of the total amount of the mixture of the polyester acrylate (A), the conjugated diene polymer (B) and the (meth) acrylic monomer (C).
The amount is 5.0 parts by mass, preferably 0.05 to 1.0 parts by mass.

The UV-curable composition of the present invention contains leveling agents, lubricants, silicone additives, fillers such as titanium oxide, polyurethane, polymethylmethacrylate, polystyrene, etc. within the range not impairing the gist of the present invention. You may further add additives, such as a polymer.

The UV-curable composition of the present invention comprises a polyester acrylate (A), a conjugated diene polymer (B), a (meth) acrylic monomer (C), a photoinitiator (D) and, if necessary, additives. Can be prepared by mixing at room temperature using conventional mixing means such as mixing using a stirring blade or a kneader.

The ultraviolet-curable composition of the present invention can be cured by irradiating it with an ultraviolet-ray source such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a fluorescent lamp, and ultraviolet rays contained in natural light. It should be noted that the irradiation time of the composition by the ultraviolet light source varies depending on the amount of energy of the ultraviolet light generated from the ultraviolet light source, but is generally 0.
It is in the range of 5 to 300 seconds.

The UV-curable composition of the present invention is excellent in compatibility and transparency, has a relatively small volume shrinkage during curing, and reduces stress during curing.
Peeling and the like are reduced, and it is also useful in applications such as adhesives and coating agents, particularly applications requiring precision.

[0027]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The details and abbreviations of the components used in the examples and comparative examples are as follows.

[1] Polyester acrylate (A) A-1: manufactured by Toagosei Co., Ltd., trade name "Aronix M"
-8030 "

[2] Conjugated diene polymer (B) B-1: An isoprene monomer is anionically polymerized in n-hexane using n-butyllithium as an initiator to give polyisoprene having a number average molecular weight of 20,000. Obtained. To 100 parts by mass of this polyisoprene, 5 parts by mass of maleic anhydride was added and reacted at 180 ° C. for 15 hours to obtain polyisoprene having 10 acid anhydride groups as an average per molecule. Next, to 100 parts by weight of the maleic anhydride-modified polyisoprene thus obtained, 6.35 parts by mass of 2-hydroxyethyl methacrylate was added, and after reacting at 120 ° C. for 8 hours, one molecule was obtained. Polyisoprene (B-1) having 10 methacryloyl groups as an average was synthesized.

B-2: An isoprene monomer was subjected to anionic polymerization in n-hexane using n-butyllithium as an initiator to obtain polyisoprene having a number average molecular weight of 10,000. To 100 parts by mass of this polyisoprene, 20 parts by mass of maleic anhydride was added and reacted at 180 ° C. for 15 hours to prepare 2 acid anhydride groups per molecule.
A polyisoprene having 0 pieces was obtained. Next, 3.5 parts by mass of 2-hydroxyethyl methacrylate was added to 100 parts by mass of the polyisoprene thus obtained, and the mixture was reacted at 120 ° C. for 8 hours after being shielded from light, and further 4.6 parts by mass of methanol. Was added and reacted with the remaining acid anhydride group at 120 ° C. for 6 hours to give polyisoprene (B-2) having 3 methacryloyl groups per molecule on average.
Was synthesized.

B-3: RICON, trade name "RIC
-3500 "(modified polybutadiene having a number average molecular weight of 6,000 and having 10 methacryloyl groups as an average per molecule)

[3] (Meth) acrylic monomer (C) C-1: isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) C-2: 1,9-nonanediol diacrylate (Osaka Organic Chemical Industry) Co., Ltd.

[4] Photoinitiator (D) D-1: manufactured by Ciba Specialty Chemicals, trade name "Darocur-1173" (2-hydroxy-2-methyl-1-phenylpropan-1-one [2 -Hydroxy-2-methylpropiophenone])

The UV curable composition thus obtained was evaluated as follows. Compatibility The uniformity of the ultraviolet curable compositions obtained in the following Examples and Comparative Examples was visually observed and evaluated. ○: Good compatibility (uniform) ×: Phase separation occurs

Cured state The ultraviolet curable compositions obtained in the following Examples and Comparative Examples were poured into a mold having a thickness of 0.5 mm, and the composition surface was thickened so as not to be affected by oxygen during curing. After covering with a polyester film of 50 μm in length,
(W / cm) was used to irradiate ultraviolet rays from an irradiation distance of 20 cm at an irradiation time of 96 seconds to obtain a cured product. After peeling the polyester film from the cured product, the case where a transparent cured product was visually observed was evaluated as ◯.

Volume Shrinkage The volume shrinkage was visually evaluated from the warped state of the cured product obtained by peeling the polyester film. ○: Volume shrinkage ○ _△ : Little volume shrinkage ×: Large volume shrinkage

Examples 1 to 9 According to the formulations shown in Table 1, polyester acrylate (A), conjugated diene polymer (B), (meth) acrylic monomer (C) and photoinitiator (D) were stirred at room temperature under stirring blades. A UV-curable composition was prepared by mixing for 20 minutes with. The results of evaluation of the obtained ultraviolet curable composition by the above method are also shown in Table 1.

Comparative Examples 1-2 Conjugated diene polymer (B) according to the formulation shown in Table 2
An ultraviolet-curable composition not using was prepared in the same manner as in Examples 1-9. The results of evaluation of the obtained ultraviolet curable composition by the above method are also shown in Table 2.

Comparative Examples 3 to 4 According to the formulations shown in Table 2, instead of the conjugated diene polymer (B) in Examples 1 to 9, the number average molecular weight was 13,0.
A UV-curable composition was prepared in the same manner as in Examples 1 to 9 using polyisoprene (LIR) of 00 or polybutadiene (LBR) having a number average molecular weight of 13,000. The results of evaluation of the obtained ultraviolet curable composition by the above method are also shown in Table 2.

Comparative Example 5 According to the formulation shown in Table 2, instead of the conjugated diene polymer (B) used in Examples 1 to 9, Kuraray Co., Ltd., trade name "LI"
R-403 "(modified polyisoprene having 3 carboxyl groups as an average per molecule and a number average molecular weight of 20,000) was used to prepare an ultraviolet curable composition in the same manner as in Examples 1 to 9. . The results of evaluation of the obtained ultraviolet curable composition by the above method are also shown in Table 2.

[0041]

[Table 1]

[0042]

[Table 2]

It can be seen from Tables 1 and 2 that the UV-curable composition having the composition specified in the present invention can give a cured product having excellent compatibility and transparency and small volume shrinkage.

[0044]

EFFECT OF THE INVENTION According to the present invention, there is provided an ultraviolet curable composition which is excellent in compatibility and transparency and which can provide a cured product having a relatively small volume shrinkage upon curing.

Claims (4)

[Claims] 1. A polyester acrylate (A) having an average of 3 or more (meth) acryloyl groups per molecule, and a conjugated diene polymer (B) having an average of 1 or more (meth) acryloyl groups per molecule. ,
(Meth) acrylic monomer (C) and photoinitiator (D)
An ultraviolet curable composition comprising as an essential component. 2. The conjugated diene polymer (B) is a polymer having one or more (meth) acryloyl groups as an average per molecule in a copolymer of polybutadiene, polyisoprene or a mixture of isoprene and butadiene. 1. The ultraviolet curable composition according to 1. 3. The (meth) acrylic monomer (C) is 10 to 30 relative to 100 parts by mass of the total amount of the mixture of the polyester acrylate (A) and the conjugated diene polymer (B).
The ultraviolet curable composition according to claim 1 or 2, which is blended in an amount of 0 part by mass. 4. The photoinitiator (D) is 0.1 to 20 relative to 100 parts by mass of the total amount of the mixture of the polyester acrylate (A), the conjugated diene polymer (B) and the (meth) acrylic monomer (C). The ultraviolet curable composition according to any one of claims 1 to 3, which is blended in a range of parts by mass.