JPH06271623A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition for coatings, adhesives, etc., consisting of a reactional product of an alkylene oxide adduct of polyol and (meth)acyclic acid and capable of providing a cured product having good hardness and adhesion by irradiation of ultraviolet rays, electron beam, etc., and heating, etc. CONSTITUTION:An alkylene oxide adduct (e.g. trimethylolpropane-ethylene oxide adduct) of a polyol, (meth)acrylate, paratoluenesulfonic acid as a catalyst, hydroquinonemonomethyl ether as a polymerization inhibitor and toluene as a solvent are charged and then heated under stirring and subjected to dehydrative esterification reaction at 110 deg.C for 5hr. This reactional liquid is washed with water and then, toluene is removed by vacuum distillation to provide the objective curable composition expressed by the formula [R<1> and R<2> are 2-4C alkyl; R<3> is H or methyl; (a) and (b) are 0-10; (c) is >=1.5; (d) is >=0.5; (a+b) >=1], capable of providing a cured material excellent in hardness and adhesion and useful for coatings, ink, adhesives, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition which gives a cured product by radical polymerization. The composition of the present invention can be easily irradiated by irradiation with active energy rays such as ultraviolet rays and electron beams, or by heating. Cured to paints, inks,
It can be used for various purposes such as an adhesive. In the present specification, acrylic acid or methacrylic acid is referred to as (meth) acrylic acid, acrylate or methacrylate is referred to as (meth) acrylate, and acryloyl group or methacryloyl group is referred to as (meth) acryloyl group.

[0002]

2. Description of the Related Art Conventionally, a composition which is cured by active energy rays such as ultraviolet rays and electron beams or heat energy has advantages such as resource saving, pollution-free and quick curing property as compared with a solvent dry curing type composition. Therefore, it is used for a wide range of purposes. Generally, the active energy ray-curable composition includes a (meth) acrylate-based prepolymer such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate or polyether (meth) acrylate, and unsaturated polyester. A resin or prepolymer as a main component. The active energy ray-curable composition usually contains phenoxyethyl (meth) acrylate, carbitol (meth) acrylate or the like in order to improve the properties of the main component, such as viscosity, curability and adhesion. Have one (meth) acryloyl group (meth)
A reactive diluent such as polyol poly (meth) acrylate such as acrylate, trimethylolpropane tri (meth) acrylate or tripropylene glycol di (meth) acrylate is blended. However, in the active energy ray-curable composition containing these reactive diluents, for example, in the composition containing (meth) acrylate having one (meth) acryloyl group, the reactivity becomes poor and the curing There is a problem that the hardness of the product is not sufficient, and in the composition containing the polyol poly (meth) acrylate, the physical properties of the composition or the cured product such as insufficient adhesiveness and unsatisfactory elasticity are affected. Was affecting. In addition to the above-mentioned (meth) acrylate-based composition, a composition comprising unsaturated polyester and styrene is known as a composition that is radically cured by heating. However, these compositions have a slow curing rate and have a problem of bad odor. Especially when these compositions are used as an adhesive, satisfactory shear strength cannot be obtained, or the adhesive part peels off. was there.

[0003]

DISCLOSURE OF THE INVENTION The present invention has excellent hardness and adhesiveness of a cured product, and has sufficient shear strength when used as an adhesive, for example, to prevent peeling of an adhesive portion. The inventors have made earnest studies to find a curable composition that does not exist.

[0004]

The present invention provides a curable composition comprising a reaction product represented by the following general formula (1) by an esterification reaction of a polyol alkylene oxide adduct and (meth) acrylic acid. It is about things.

[0005]

[Chemical 2]

Here, each symbol has the following meaning. R: Residue of polyol having 3 to 15 carbon atoms and c + d hydroxyl groups R ¹ : alkyl group having 2 to 4 carbon atoms R ² : alkyl group having 2 to 4 carbon atoms R ³ : hydrogen or methyl Group a: Positive number of 0 to 10 b: Positive number of 0 to 10 c: Positive number of 1.5 or more d: Positive number of 0.5 or more However, a + b ≧ 1. Hereinafter, the present invention will be described in detail.

In the curable composition of the present invention, the reaction product represented by the above general formula (1) [hereinafter simply referred to as reaction product] is based on 1 mol of an alkylene oxide adduct of a polyol having c + d hydroxyl groups. Thus, c moles of (meth) acrylic acid are esterified.
The reaction amount of (meth) acrylic acid is the theoretical amount c mol per mol of the alkylene oxide adduct of polyol, but in the actual reaction, the amount charged should be appropriately increased or decreased in consideration of the reactivity of both. You can also

The alkylene oxide adduct of polyol is obtained by adding alkylene oxide having 2 to 4 carbon atoms to polyol. Polyol has hydroxyl group c +
d is an alcohol having 3 to 15 carbon atoms, and specific examples thereof include trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, sorbitol, ditrimethylolpropane, ditrimethylolethane, diglycerin, dipentaerythritol. , Tritrimethylolpropane, tritrimethylolethane, tripentaerythritol and the like. The polyol preferably has a molecular weight of 260 or less. If the molecular weight exceeds 260, the viscosity becomes too high, and it may be difficult to handle. R in the general formula (1)
Is a residue of the above polyol, that is, a group obtained by removing a hydroxyl group from the polyol. Specific examples of the alkylene oxide having 2 to 4 carbon atoms include ethylene oxide, propylene oxide and butylene oxide. The amount of alkylene oxide added to one hydroxyl group of the polyol, that is, the values of a and b in the general formula (1) is 0.
Must be a positive number from -10. A reaction product having a value of more than 10 has a low crosslink density and a cured product having a low hardness. R ¹ and R in the general formula (1)
² is a divalent group derived from the above alkylene oxide, which is a linear or branched alkylene group having 2 to 4 carbon atoms.

The above-mentioned method of reacting the alkylene oxide adduct of polyol with (meth) acrylic acid can be carried out by a commonly known esterification reaction. For example, in an organic solvent such as benzene, toluene, xylene or cyclohexane, an alkylene oxide adduct of the above polyol, an acid catalyst such as (meth) acrylic acid, paratoluenesulfonic acid or sulfuric acid, and hydroquinone, hydroquinone monomethyl ale, catechol or phenothiazine. A method of mixing a polymerization inhibitor such as the above and heating with stirring to perform dehydration esterification can be mentioned. As the organic solvent, those which are difficult to dissolve in water are preferable because they facilitate separation of water as a by-product and facilitate the progress of dehydration reaction. The obtained compound may be purified by a conventional method, for example, a method in which the reaction solution is washed with water and then the solvent is removed by distillation under reduced pressure.

The reaction product is not a single compound but a composition composed of a plurality of compounds having different chemical structures, and a, b, c and d in the general formula (1) are all reaction products. The average value of each compound is shown. For example, 1 mole of trimethylolpropane and 3 moles of ethylene oxide are reacted with 1 mole of acrylic acid to react with 2 moles of acrylic acid, and a and b are both 1, c is 2 and d is d.
A reaction product of 1 is produced. In this case, the ethylene oxide adduct of trimethylolpropane, which is a raw material, is mainly composed of trimethylolpropane with one molecule of ethylene oxide added to each of the three hydroxyl groups. Two molecules or more of ethylene oxide condensed and added only to hydroxyl groups, one molecule of ethylene oxide added to only one hydroxyl group, or one molecule of ethylene oxide added to each of two hydroxyl groups. And the like are included, and a and b are 1 as an average value. further,
The compound obtained by the esterification reaction of 2 mol of acrylic acid with this is also a compound of 3 mol in which one molecule of ethylene oxide is added to each of the three hydroxyl groups of trimethylolpropane. The main product is a compound (c = 2, d = 1) in which acrylic acid is added to each of the above two compounds, but in addition to this, a compound (c = 1, d = 2) in which one acrylic acid is added Or a compound with three additions (c =
3, d = 0) etc. are also produced at the same time, and c in the reaction product
And d are 2 and 1 as an average value, respectively.

The reaction product must have a value of a + b of 1 or more, that is, one in which at least one alkylene oxide is added in one molecule. When the value of a + b is less than 1, the curing shrinkage is large and the adhesion to the substrate is poor, and when it is used as an adhesive, satisfactory shear strength cannot be obtained, or the adhesive part peels off. To do.

C, which represents the average value of the number of (meth) acryloyl groups of each compound in the reaction product, must be a positive number of 1.5 or more, and preferably 1.8 to 5. c is 1.
If it is less than 5, the curing reactivity decreases. On the other hand, when it exceeds 5, the shrinkage during curing is severe and the adhesion to the substrate may be reduced. D, which represents the average number of hydroxyl groups of each compound in the reaction product, must be a positive number of 0.5 or more, and is preferably 1 to 3. d is 0.
If it is less than 5, the adhesion to the substrate may be poor,
When it is used as an adhesive, the adhesive part peels off.
On the other hand, when d exceeds 3, the cured product has a low Tg,
The film formability may be poor.

Further, in the reaction product, the average value of alkylene oxide present in each compound, that is, a × c + b ×
The value of d is preferably 2-10. This value is 2
If it is less than 10%, the shrinkage during curing is large, and the adhesion to the substrate may be reduced. On the other hand, if it exceeds 10, the crosslink density of the cured product is low and sufficient hardness is exhibited in the cured product. It may disappear or the curing speed may slow down.

The reaction product may be used alone or in combination of two or more in the composition of the present invention.

The composition of the present invention may optionally contain various components in the reaction product. For example, organic solvents, water or reactive diluents can be included to reduce the viscosity of the composition.

Examples of the organic solvent include ketones such as methyl ethyl ketone or methyl isobutyl ketone, acetic acid esters such as ethyl acetate or butyl acetate, aromatic hydrocarbons such as toluene or xylene, alcohols such as methanol or isopropyl alcohol, Examples thereof include cellosolves such as methyl cellosolve or ethyl cellosolve, cellosolve acetates such as methyl cellosolve aceetate or ethyl cellosolve acetate, and one or more of them can be used.

A typical example of the reactive diluent is a compound having a (meth) acryloyl group in the molecule, and a compound having a viscosity of 50 cps or less at 25 ° C. has a large effect of lowering the viscosity of the composition. preferable. A compound having a (meth) acryloyl group in the molecule is commercially available, for example, tetrahydrofurfuryl acrylate [Osaka Organic Chemical Industry Co., Ltd. Viscoat 150], phenoxyethoxyethyl acrylate [Toagosei Chemical Industry Co., Ltd. Aronix M101. ], Neopentyl glycol diacrylate [Viscoat 215 manufactured by Osaka Organic Chemical Industry Co., Ltd.], hexanediol diacrylate [viscoat 230 manufactured by Osaka Organic Chemical Industry Co., Ltd.], and the like, and one or more of these may be used. Can be used.

When the reactive diluent is mixed, the ratio is 100 parts by weight or less relative to 100 parts by weight of the reaction product, and when the organic solvent or water is mixed, the ratio is the reaction product and the reactive diluent. It is preferable that the total amount of these (hereinafter referred to as curable components) is 100 parts by weight, and 100 parts by weight or less.

The composition of the present invention may contain a stabilizer in order to prevent gelation during storage and increase storage stability. Suitable stabilizers include, for example, phenols such as hydroquinone, hydroquinone monomethyl ether, t-butyl hydroquinone and catechol, quinones such as benzoquinone, naphthoquinone and diphenylbenzoquinone, phenothiazine and copper salts. The amount of these stabilizers used is preferably 0.00001 to 0.01 part by weight based on 100 parts by weight of the curable component.

The composition of the present invention can be cured by various methods, and a radical polymerization initiator can be added to the composition and cured by heating or light. heating furnace,
When heat curing is performed mainly using a heat energy source such as infrared rays and microwaves, a heat polymerization initiator is added. Suitable thermal polymerization initiators include, for example, azo compounds such as azoisobutyronitrile, ketone peroxides such as methylethylketone peroxide or cyclohexanone peroxide, hydroperoxides such as diisopropylbenzene hydroperoxide or diquat. Alkyl peroxides such as milperoxide, acyl peroxides such as benzoyl peroxide or toluoyl peroxide, and various organic peroxides such as peroxyesters such as cumylperoxyoctoate or butylperoxyisobutyrate. Examples thereof include inorganic peroxides such as ammonium persulfate. When left to stand at room temperature for heat curing or for heat curing at a relatively low temperature of 100 ° C. or lower, it is preferable to add a polymerization accelerator together with the above thermal polymerization initiator, and a preferable polymerization accelerator is, for example, cobalt. , Organic metal salts of metals such as iron or manganese with naphthenic acid, linoleic acid or acetylacetone, dimethyl paratoluidine,
Examples include reducing amines such as ascorbic acid and other reducing substances.

When the composition is cured by irradiation with ultraviolet rays or visible rays, generally used photoinitiators and sensitizers are added. Preferred photoinitiators include benzophenone and its derivatives, benzoin, benzoin alkyl ether, 2-methyl [4- (methylthio) phenyl] -2-morpholino-1-propanone, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone and the like. Can be mentioned.

When the composition is cured by both photocuring and thermo-heavy curing, the photopolymerization initiator and the thermal polymerization initiator may be used in combination.

The amounts of these thermal polymerization initiator and polymerization accelerator, as well as the photoinitiator and sensitizer, to be compounded may be in accordance with a conventional method.
Generally 0.01 to 2 with respect to 100 parts by weight of the curable component.
0 parts by weight is preferred. If it is less than 0.01 part, the composition cannot be sufficiently polymerized, and if it exceeds 20 parts, the amount of the curable component is relatively decreased, and thus the properties of the cured product may be deteriorated. The particularly preferable amount of the initiator used is 0.1 to 10 parts.

When the composition is cured by irradiation with an electron beam or radiation, a polymerization initiator may not be used.

In addition to the above, a pigment, a dye, a filler, a leveling agent, an adhesion-imparting agent and / or an antifoaming agent may be added to the composition of the present invention, if necessary.

[0026]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, the display of parts or% in each example is based on weight unless otherwise specified. Synthesis Example 1 A flask equipped with a stirrer, a thermometer, and a water separation tube having a cooling tube attached to the upper part thereof was added with 3.0 mol of ethylene oxide of trimethylolpropane (average molecular weight: 270).
0 g (1 mol), 144 g (2 mol) of acrylic acid, 17 g of paratoluenesulfonic acid as a catalyst (2% based on the whole reaction product), 0.2 g of hydroquinone monomethyl ether as a polymerization inhibitor (250 pp based on the whole reaction product).
m) and 414 g of toluene (50% based on the whole reaction product) as a solvent, and then heated with stirring to give a reaction temperature of 1
The dehydrated ester reaction was carried out at 10 ° C. for 5 hours. The amount of water accumulated in the water separation tube was 34 g. After the completion of the reaction, the reaction solution was washed with water, and then toluene was removed by distillation under reduced pressure to obtain a reaction product containing dimethylolpropane-3.0 mol of ethylene oxide as a main component of diacrylate.
This is designated as Composition A. The symbols in the general formula (1) of this reaction product are as follows. R: trimethylolpropane residues (carbon number = 6) R _1: Ethylene (carbon number = ₂₎ R 2: ethylene (number of carbon atoms = 2) R _3: hydrogen a: 1.0 b: 1.0 c: 1 .9 d: 1.1

Synthesis Example 2 Propylene oxide 3.0 of trimethylolpropane
310 g (1 mol) of a molar adduct (average molecular weight 310),
Acrylic acid 144 g (2 mol), paratoluene sulfonic acid 18 g as catalyst (2% based on the whole reaction product), hydroquinone monomethyl ether 0.2 as polymerization inhibitor
The dehydration ester reaction was carried out in the same manner as in Synthesis Example 1 using g (250 ppm based on the entire reaction product) and 454 g of toluene (50% based on the entire reaction product) as a solvent. The amount of water accumulated in the water separation tube was 36 g. Post-treatment was carried out in the same manner as in Synthesis Example 1 to obtain a reaction product containing, as a main component, a diacrylate of a propylene oxide 3.0 mol adduct of trimethylolpropane. This is designated as Composition B. The symbols in the general formula (1) of this reaction product are as follows. R: trimethylolpropane residues (carbon number = 6) R _1: Propylene (carbon number = 3) R _2: Propylene (carbon number = ₃₎ R 3: hydrogen a: 1.0 b: 1.0 c: 2 0.0 d: 1.0

Synthesis Example 3 Ethylene oxide of ditrimethylolpropane 4.2
Molar adduct (average molecular weight 435) 435 g (1 mol),
Acrylic acid 216 g (3 mol), paratoluene sulfonic acid 26 g as catalyst (2% based on the whole reaction product), hydroquinone monomethyl ether 0.3 as polymerization inhibitor
g (250 ppm based on the whole reaction product) and toluene 651 g (50% based on the entire reaction product) as a solvent were used to carry out the dehydration ester reaction in the same manner as in Synthesis Example 1. The amount of water accumulated in the water separation tube was 51 g. Post-treatment was carried out in the same manner as in Synthesis Example 1 to obtain a reaction product containing, as a main component, triacrylate of 4.2 mol of ethylene oxide of ditrimethylolpropane. This is designated as Composition C. The symbols in the general formula (1) of this reaction product are as follows. R: Jitorimechiro - trimethylolpropane residues (carbon number = 12) R _1: Ethylene (carbon number = ₂₎ R 2: ethylene (number of carbon atoms = 2) R _3: hydrogen a: 1.05 b: 1.05 c: 2 .85 d: 1.15

Synthesis Example 4 683 g (1 mol) of butylene oxide 7.6 mol adduct of pentaerythritol having a molecular weight of 683, 172 g (2 mol) of methacrylic acid, and 34 g of paratoluenesulfonic acid as a catalyst (2% based on the whole reaction product). ), Hydroquinone monomethyl ether 0.4 g (250 ppm based on the whole reaction product) as a polymerization inhibitor, and 855 g toluene (50% based on the whole reaction product) as a solvent, and a dehydrated ester in the same manner as in Synthesis Example 1. The reaction was carried out. The amount of water accumulated in the water separation tube was 34 g. Post-treatment was carried out in the same manner as in Synthesis Example 1 to obtain a reaction product containing pentaerythritol as a main component of dimethacrylate of 7.6 mol of butylene oxide. This is designated as Composition D. The symbols in the general formula (1) of this reaction product are as follows. R: pentaerythritol residue (carbon number = 5) R _1: polybutylene (carbon number = 4) R _2: polybutylene (carbon number = 4) R _3: methyl a: 1.9 b: 1.9 c: 1. 9d: 2.1

Examples 1 to 4 100 parts of each composition shown in Table 1 and 2 parts of benzyl dimethyl ketal as a photopolymerization initiator were added and mixed as a photopolymerization initiator to prepare a curable composition. The evaluation results are shown in Table 1.

Comparative Examples 1 to 4 100 parts of each composition shown in Table 1 and 2 parts of benzyl dimethyl ketal as a photopolymerization initiator were added and mixed as a photopolymerization initiator to prepare a curable composition. The evaluation results are shown in Table 1.

Evaluation Method Each composition was applied on a steel plate panel in a thickness of 10 μm and cured by ultraviolet rays or electron beams under the following conditions. Further, it was similarly coated on the oak plate with a thickness of 30 μm and similarly cured. The pencil hardness and the adhesiveness of the obtained cured coating film were measured.・ Ultraviolet irradiation Ultraviolet lamp: 80 W / cm, high pressure mercury lamp, focal length: 10 cm Reflective plate: Concentrating type conveyor speed: 5 m / min Irradiation frequency: 5 times ・ Electron beam irradiation accelerating voltage: 170 kV Irradiation dose: 5 Mrad oxygen concentration : 100 to 200 ppm ○ Pencil hardness Measured according to JIS5400. 〇 Adhesion 100 pieces of goggles were cut on the coating film with a cutter knife within a range of 10 mm × 10 mm, cellophane tape was pressure-bonded, and then peeled off vigorously. It is shown by the number of gobang.

[0033]

[Table 1]

Aronix M309: trimethylolpropane triacrylate [Toagosei Chemical Industry Co., Ltd.
Aronix M310: trimethacrylate of propylene oxide 3 mol adduct of trimethylolpropane [manufactured by Toagosei Kagaku Kogyo Co., Ltd.] Light ester TMP: trimethylolpropane trimethacrylate [Kyoeisha Yushi Kagaku Kogyo ( Aronix M270: polypropylene glycol diacrylate [manufactured by Toagosei Chemical Industry Co., Ltd.]

Examples 5 and 6 100 parts of each composition shown in Table 2 and 2 parts of benzoyl peroxide as a thermal polymerization initiator were added and mixed to prepare a curable composition. Each composition is 20μ thick on a oak board.
And coat another coated oak board on the coated surface.
A test piece was prepared by heating at 0 ° C. for 8 hours. The tensile shear strength of the obtained test piece was measured according to JIS K 6851. The evaluation results are shown in Table 2.

Comparative Examples 4 and 5 100 parts of each composition shown in Table 2 and 2 parts of benzoyl peroxide as a thermal polymerization initiator were added and mixed to prepare a curable composition. When each composition was cured in the same manner as in Example 5, the evaluation results were as shown in Table 2.

[0037]

[0038]

The composition of the present invention is easily cured by irradiation with active energy rays such as ultraviolet rays and electron beams or by heating, and the cured product has excellent hardness and adhesion, and is used as an adhesive. Since it has sufficient shear strength and does not peel off the adhesive portion, it can be prized for various applications such as paints, inks and adhesives.

Claims (1)

[Claims] 1. A curable composition comprising a reaction product represented by the following general formula (1) obtained by reacting an alkylene oxide adduct of a polyol with (meth) acrylic acid. [Chemical 1] Here, each symbol has the following meaning. R: Residue of polyol having 3 to 15 carbon atoms and c + d hydroxyl groups R ¹ : alkyl group having 2 to 4 carbon atoms R ² : alkyl group having 2 to 4 carbon atoms R ³ : hydrogen or methyl Group a: Positive number of 0 to 10 b: Positive number of 0 to 10 c: Positive number of 1.5 or more d: Positive number of 0.5 or more However, a + b ≧ 1.