JPH01229018A - Composition hardenable by energy ray - Google Patents

Abstract

PURPOSE:To obtain the subject composition having remarkably excellent surface hardenability and rate of cure in spite of low viscosity and giving a cured product having high hardness, by compounding a specific polyfunctional oligomer and pentaerythritol tetraacrylate at a specific ratio. CONSTITUTION:The objective composition can be produced by compounding (A) 30-90wt.% of a polyfunctional oligomer obtained by reacting (i) a dibasic acid and/or its anhydride with (ii) pentaerythritol and (iii) acrylic acid and containing the unit of the component (i) and (B) 70-10wt.% of pentaerythritol tetraacrylate. The component A is produced preferably by charging the components (i)-(iii), a reaction solvent acting also as a dehydrating azeotropic agent and an esterification catalyst into a reactor furnished with a stirrer, a thermometer, an air-blasting tube and a water-separator and reacting the components with each other under heating while removing the produced water as an azeotropic mixture with the dehydrating azeotropic agent from the system.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The composition provided by the present invention can be cured in a short time by irradiation with energy rays such as electron beams and ultraviolet rays, and can form a high coating film. It can be used in various industrial fields as a coating agent or cast molding material that requires hardness.

[Prior Art] Polyester acrylate, which is a type of polyfunctional oligomer, is produced by condensation telomerization of polyhydric alcohol, polybasic acid or its anhydride, and acrylic acid. By controlling the type and ratio of the polybasic acid or its anhydride, curable compositions with various properties can be obtained. In general, the larger the number of reaction molecules (hereinafter referred to as the degree of condensation) of polybasic acid with polyhydric alcohol molecules, the higher the molecular weight of the polyester acrylate produced, which has excellent properties such as adhesion and hardness. A cured product can be obtained.

However, polyester acrylate, which has become a polymer with a high molecular weight, is a highly viscous liquid, so by adding a reactive diluent, it is used as a low-viscosity liquid with good workability.

Furthermore, in order to accelerate curing, a photoinitiator or the like is added to polyester acrylate that is cured by irradiation with ultraviolet rays.

The above-mentioned reactive diluent must be -C: - Low viscosity, low odor, low skin irritation, and high boiling temperature - Excellent compatibility with oligomers and caloric additives - Curing Materials that meet the following conditions are used: excellent properties and physical properties of the cured product, and low cost.For example, diethylene glycol diacrylate and trimethylolpropane have an acryloyl group, which is a polymerizable functional group, in the molecule. Examples include triacrylate.

Polyester acrylate has the advantage of being able to obtain a cured product with excellent properties such as adhesion and hardness, but on the other hand, the curing of polyester acrylate is suppressed in the presence of air, so it is difficult to cure despite its good internal curing properties. has the disadvantage of poor surface hardening properties.

In order to improve the surface curability of polyester acrylate, there are two methods: using a photoinitiator and modifying the polyester acrylate itself.

One method of improving surface curing properties using a photoinitiator is to add an amine-based photosensitizer, but this method causes problems such as decreased storage stability, yellowing after curing, and decreased chemical resistance. The problem is that it is not practical.

As a method for improving surface hardening properties by modifying polyester acrylate, polyfunctionalization of polyester acrylate can be mentioned.
Polyfunctional compounds have been proposed that consist of ((+II, for example [
” Book Adhesive Association Magazine vol. 1.20. No.

7.1984. Since these polyfunctional compounds have many acryloyl 75 polymerizable functional groups in one molecule, the curability of polyester acrylate (see page 24) is significantly improved. The problem with is resolved. However, since these polyfunctional compounds alone have extremely high viscosity, they have poor workability when used as a coating material or as a molding material, and they require the addition of a diluent due to their undesirable properties. do. However, such reactive diluents are not fully satisfactory because they deteriorate the surface curing properties, curing speed, etc. of the curable resin, as well as the adhesion, hardness, etc. of the cured product.

1. 18F to be solved by the present invention The present invention solves the above-mentioned problems of polyester acrylate, and is a composition that can be cured by irradiation with energy rays such as electron beams and ultraviolet rays, and has a low viscosity. It has excellent surface hardening properties and hardening speed, and the cured product has high hardness.

(B) Structure of the Invention [Means for Solving the Problems] As a result of intensive research, the present inventors have discovered that the present inventors have discovered that the present inventors have found that the present invention is based on the reaction product of a dibasic acid and/or its anhydride, pentaerythritol, and acrylic acid. Compositions consisting of a special polyfunctional oligomer and pentaerythritol tetraacrylate, in which the ratio of these is within a specific range, exhibit the excellent properties of the polyfunctional oligomer, such as good surface curing properties and fast curing properties. The present inventors have discovered that it is possible to reduce the viscosity of the composition without compromising on the viscosity of the composition, and have completed the present invention.

Particularly, the present invention relates to an energy ray curable composition containing the following compositions (a) and (b) as main components.

(a) A polyfunctional oligomer that is a reaction product of a dibasic acid and/or its anhydride, pentaerythritol, and acrylic acid and has the dibasic acid and/or its anhydride at the rp position in the molecule = 30 to 90 wt % (b) Pentaerythritol tetraacrylate 70~
lQwt% <Polyfunctional oligomer> The polyfunctional 11-functional oligomer, which is a component of the energy ray-curable composition in the present invention, is a coesterification reaction of dibasic acid and/or its anhydride, pentaerythritol, and acrylic acid. This is obtained by

Examples of the dibasic acid and/or its anhydride include succinic acid, adipic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, Himic. Examples include various dibasic acids such as acids, endo acids, and het acids, and acid anhydrides thereof.

As a method for producing the polyfunctional oligomer, for example, the following method is preferable.

That is, a dibasic acid and/or its anhydride, pentaerythritol and acrylic acid, and a reaction solvent which usually preferably also serves as a dehydration entrainer are placed in a reactor equipped with a stirrer, a thermometer air blowing tube and a water separator. and an esterification catalyst are charged and reacted under heating, and the produced water is removed from the system as an azeotropic mixture with a dehydration azeotropic agent.

The end point of the reaction is determined by the amount of water produced as a by-product, etc. The reaction product liquid is washed with an aqueous alkali solution and water, the aqueous layer is separated and removed, and the dehydration entrainer is removed under reduced pressure to form a polyfunctional A reaction product containing sexual oligomers is obtained.

Further, this reaction can also be carried out by a two-stage reaction method in which raw materials are supplied in portions or by a sequential reaction method in which raw materials are added sequentially.

The molar ratio of each raw material is (A) dibasic acid and/or its anhydride: (B) pentaerythritol: (C) acrylic acid: (CB) 1.8 to 1 mole of (A) 2
．． 2 mol (C) range of 4.5 to 7.2 mol (preparation ratio (
1) is preferred, and more preferably (B) is 2 moles and (C) is 6 to 6.8 moles per 1 mole of (A).

In addition to acrylic acid itself, the raw material acrylic acid includes acrylic acid lower alkyl esters, acrylic acid halides, etc., which cause reactions equivalent to esterification through transesterification and addition reactions. Various derivatives of acrylic acid can also be used. The term acrylic acid used in the present invention is intended to include these derivatives.

In addition, there are many examples where the coesterification reaction of polybasic acid, polyhydric alcohol, and acrylic acid is described as if a single compound is obtained, but as in many other documents, Also, the gel permeation of the product
As revealed by chromatographic analysis,
In fact, it is never a single compound, but has various structures with different degrees of condensation, such as polyol polyacrylate and dibasic acid and/or its anhydride formed by the reaction of polyhydric alcohol and acrylic acid, and the reaction of polyhydric alcohol and acrylic acid. It generally consists of a mixture with a polyfunctional oligomer having a dibasic acid and/or its anhydride unit in the molecule.

Therefore, even in the coesterification reaction for producing the polyfunctional oligomer constituting the composition of the present invention, the product obtained is actually mainly composed of the polyfunctional oligomer with a degree of condensation of 1 or more, and the polyol polyacrylate Pentaerythritol tetraacrylate, a type of acrylate, is produced as a by-product.

Under the conditions of the raw material charging ratio (1), the amount of pentaerythritol tetraacrylate produced is usually 5 wt% or less, so in this case, the content can be increased by blending separately produced pentaerythritol tetraacrylate. It is necessary to adjust the temperature within the above range.

The heating conditions in the coesterification reaction are 50 to 150"
The reaction temperature is preferably about C, and the reaction can be carried out under normal pressure, reduced pressure, or increased pressure.

As the dehydration entrainer, n-hexane, n-hebutane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, trichloroethylene, tetrachloroethylene, diisopropyl ether, etc. are preferably used.

In addition, as the esterification catalyst, sulfuric acid, hydrochloric acid, phosphoric acid, fluoroboric acid, P-)luenesulfonic acid, methanesulfonic acid, cationic ion exchange resin, and other esterification catalysts are usually used in the esterification reaction. amount used.

The coesterification reaction is preferably carried out in the presence of a polymerization inhibitor, and examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, p-henzoquinone, and
-Butylcatechol, phenothiazine, copper chloride, etc. are preferably used.

Furthermore, in order to effectively prevent undesired polymerization during the reaction, it is preferable to blow air into the reaction solution.

<Pentaerythritol tetraacrylate> Pentaerythritol tetraacrylate (hereinafter abbreviated as PETA), which is another component of the energy ray curable composition in the present invention, is produced by using pentaerythritol without using dibasic acid and/or its anhydride as a raw material. It can be produced by almost the same method as in the case of producing polyfunctional oligomers, except for using two components: and acrylic acid.

Energy ray curable composition> The energy ray curable composition of the present invention is produced by blending PETA with the polyfunctional oligomer as necessary.
Polyfunctional oligomer 30~9QwL% and PETA70~
A more preferable composition is 50 to 75 wt% of polyfunctional oligomer and 50 to 25 wt% of PETA.
It is. If the content of PETA is less than 1Qwt%,
This is unsuitable because the viscosity of the energy beam curable composition increases, making it difficult to use it as a coating face. On the other hand, if the content of PETA is more than 7 owt%, the adhesiveness of the cured coating film of the energy ray curable composition deteriorates, and practicality is lost.

The energy ray curable composition of the present invention can be produced by changing only the charging ratio of raw materials during the production of the polyfunctional oligomer,
A predetermined amount of PET is produced by increasing the by-product ratio of
It is also possible to produce the composition in bulk as a composition containing A.

In the case of batch production, the charging ratio of each raw material can be determined by summing the amount of raw materials necessary for producing the polyfunctional oligomer and PETA, taking into account PETAAll produced as a by-product during the coesterification reaction. (A) 2.5 to 6.0 moles of pentaerythritol (C) 7.2 to 26 moles of acrylic acid per mole of dibasic acid and/or its anhydride, and The reaction may be carried out in such a range that the ratio of the total number of carboxyl groups of dibasic acid and/or its anhydride and acrylic acid to the number of hydroxyl groups of erythritol is 0.9 to 1.2.

Other Components> In the energy ray-curable composition of the present invention, a photoinitiator is used when the curing means is ultraviolet rays. Suitable photoinitiators include evabenzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin octyl ether, benzoin compounds,
Examples include carbonyl compounds such as benzyl, diacetyl, methylanthraquinone, acetophenone, and benzophenone, and are used in an amount of 0.01 to 20 wt%, preferably 0.1 to 10@t%, based on the polymerizable component. When the curing means is an electron beam, the curing occurs quickly without using an initiator.

The irradiation with ultraviolet rays and electron beams may be carried out under the conditions commonly used for curing compositions containing a compound having an acryloyl group as a polymerization component.

There is no problem in using a solvent in the composition of the present invention depending on the purpose of use. For example, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate,
It is also possible to dilute the composition of the present invention with acetic acid esters such as butyl acetate, aromatic hydrocarbons such as benzene, toluene, xylene, or other commonly used organic solvents.

It is also possible to add soluble polymers to the composition of the present invention to the extent that they can be dissolved; examples thereof include lower alkyl esters of acrylic acid, lower alkyl esters of methacrylic acid, styrene, and acetic acid. vinyl, acrylic acid,
Examples include homopolymers of monomers such as methacrylic acid and copolymers thereof.

In addition, various organic or inorganic fillers such as silica, talc, etc., or various conventionally used additives such as leveling agents, antifoaming agents, etc. can also be blended.

These may be blended according to conventional blending amounts.

[Examples, etc.] The present invention will be explained in more detail by showing Examples, Comparative Examples, and Reference Examples below. The various characteristic values shown in Examples, Comparative Examples, and Reference Examples are values measured under the following conditions.

<viscosity> It was measured using an ED type viscometer manufactured by Tokyo Keiki ■.

Light curing> As an ultraviolet irradiator, 2 lamps are placed 10 cm vertically below an 80 W/cm high-pressure mercury lamp (Ushio Inc., ozone condensing type 1 lamp).
A device equipped with a belt that moves at 0-/so in was used.

A photocurable composition is coated on a polycarbonate resin (hereinafter abbreviated as PC) board to a thickness of about 10 μm using a laboratory coach-in-blonde, and then attached to the belt of an ultraviolet irradiator, Ultraviolet rays were irradiated by passing through the ultraviolet irradiation area, and the number of irradiations until the surface lost its tackiness was measured.

Adhesion> PC obtained by photocuring under the same conditions as the photocurability measurement.
Draw 11 vertical and horizontal parallel lines at intervals of hl on the coating on the board or hard vinyl chloride resin (hereinafter abbreviated as PVC) board, so that 100 squares are created within 1 cm. After making a cut in the shape of a cut, a cellophane adhesive tape (manufactured by Chiban Co., Ltd.) was applied, and the tape was then peeled off to measure the number of base marks remaining on the PC board or PVC board.

<Pencil hardness> JIS-
5400 6.14.

Reference Examples 1 to 7 Various polyfunctional oligomers were prepared by the following operations. In addition, in the following, parts are parts where m is placed, and % is weight %.

In a reactor equipped with a stirrer, a thermometer, an air blowing tube, and a water separator, dibasic acid anhydrides of the types and amounts shown in Table 1, polyhydric alcohols, and acrylic acid of the amount shown in Table 1, 96 % sulfuric acid, phenothiazine and toluene, and 50% air.
Heating was carried out while blowing at a rate of m1/min and stirring.

The distilled azeotropic mixture was cooled and separated into a toluene layer and an aqueous layer, the toluene layer was returned to the reactor, and the aqueous layer was removed from the system. After reacting with stirring for the time shown in Table 1, cooling
Wash with 600 parts of 10% caustic soda aqueous solution, and add 10 parts of
% ammonium sulfate aqueous solution. 0.50 part of hydroquinone moa/methyl ether was added to the washing solution, and toluene was removed by vacuum 11 at 80°C to obtain a reaction product.

The reaction product consists of a polyfunctional oligomer having a dibasic acid anhydride residue in the molecule and a polyol polyacrylate,
Its acid value, viscosity, PETA content, yield, etc. are shown in Table 1.

Reference example 8 PETA was synthesized by the following procedure.

136 parts of pentaerythritol and 34 parts of acrylic acid were added to a reactor equipped with a stirrer, a thermometer, an air blowing tube, and a water separator.
6 parts, 96% sulfuric acid 41.9 parts, phenothiazine 0.07
1 part and 698 parts of toluene were charged, and the mixture was heated while blowing air at a rate of 50 ml/min and stirring.

When the liquid temperature reached 105°C, water produced by the reaction began to distill out as an azeotrope with toluene.

The azeotropic mixture was cooled and separated into a toluene layer and an aqueous layer, the toluene layer was returned to the reactor, and the aqueous layer was removed from the system.1 As the reaction progressed, the liquid temperature rose, and after 5 hours, the liquid temperature reached 115
℃ and 75.6 parts of water (dehydration rate 105%) vti was released.

Therefore, the reaction solution was cooled and 10% caustic soda aqueous solution 3
00 parts, and then 10% ammonium sulfate aqueous solution 3
Washed with 00 parts. 0.14 parts of hydroquinone monomethyl ether was added to the washing liquid, and toluene was removed by vacuum distillation at 80°C to obtain 282 parts of PETA.

PETA is a brown viscous liquid with an acid value of 0.03-g-KO.
) l/g, viscosity 560 cps/25°C1 residual toluene 0.4%.

Examples 1 to 7 Reaction products obtained in Reference Examples 1 to 3 and PE obtained in Reference Example 8
TA was blended in the proportions shown in Table 2, and 1% of Irgacure 651 (manufactured by Ciba Geigy, trade name) as a photoinitiator was dissolved therein to prepare a synthetic radiation-curable composition.

Table 2 shows the viscosity and photocurability of the obtained energy beam curable composition, as well as the pencil hardness and adhesion of the cured product.

Comparative Examples 1 to 9 Polyol polyacrylate was added as a reactive diluent to the reaction products obtained in Reference Examples 1 to 7 in the proportions shown in Table 3, and Irgacure 651 (manufactured by Ciba Geigy) was added as a photoinitiator. (trade name) was dissolved at 1% to prepare an energy ray curable composition.

Table 3 shows the viscosity and photocurability of the resulting composition, as well as the pencil hardness and adhesion of the cured product.

Example 8 291 parts of pentaerythritol, 51.8 parts of phthalic anhydride, 649 parts of acrylic acid, and 39.6 parts of 96% sulfuric acid were placed in a reactor equipped with a stirrer, a thermometer, an air blowing tube, and a water separator.
1 part, 0.09 part of phenothiazine and 950 parts of toluene were charged, and heated while blowing air at a rate of 50@l/min and stirring.

When the liquid temperature reached 105"C, the water produced by the reaction began to distill out as an azeotrope with toluene. The azeotrope was cooled and separated into a toluene layer and an aqueous layer, and the toluene layer was sent to the reactor. The water layer was removed from the system.As the reaction progressed, the liquid temperature rose, and after 10 hours, the liquid temperature reached 115°C.
141 liters of water (dehydration rate 95%) was distilled out.

Therefore, the reaction solution was cooled and washed with 530 parts of a 10% caustic soda aqueous solution, and further washed with 530 parts of a 10% ammonium sulfate aqueous solution. PETA was reduced to 45% by adding 0.32 parts of hydroquinone monomethyl ether to the washing solution and removing toluene by vacuum distillation at 80°C.
610 parts of a reaction product, the remainder being a polyfunctional oligomer having a phthalic anhydride residue in the molecule, was obtained.

This product is a brown viscous liquid with an acid value of 15.14 g-KO.
II/g, viscosity 9, 800 cps/25°C5, residual toluene 0.4%.

A curable composition was prepared by dissolving 1% of Irgacure 651 (trade name, manufactured by Ciba Geigy) as a photoinitiator. As a result of evaluating the physical properties of the obtained composition, the photocurability was 2 times, and the pencil hardness of the cured product was 5) 1. Adhesion is PC,
Both PVCs were 100.

(c) Effects of the Invention The composition of the present invention rapidly hardens not only the inside but also the surface by irradiation with energy rays such as ultraviolet rays or electron beams.
The cured product can firmly adhere to the adherend and have high hardness both inside and on the surface layer. Moreover, since the composition of the present invention is a low-viscosity liquid and has excellent workability, the above characteristics can be fully utilized, making it extremely useful in various industrial fields.

Claims (1)

[Scope of Claims] 1. An energy ray curable composition containing as a main component a composition consisting of the following (a) and (b). (a) A reaction product of a dibasic acid and/or its anhydride, pentaerythritol, and acrylic acid, a polyfunctional oligomer having a dibasic acid and/or its anhydride unit in the molecule, 30 to 90 wt% ( b) Pentaerythritol tetraacrylate 70~
10wt%