JPH0564971B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a curable composition suitable for paints, coating agents, lining agents, adhesives, etc., and particularly to a composition curable by irradiation with energy rays such as light and electron beams. [Prior art] It is known to use a polyethylene compound or oligomer having two or more ethylenically unsaturated bonds in one molecule together with a polythiol compound and to prepare a photocurable resin composition by adding a photoreaction initiator. It is. Ethylenically unsaturated bonds include allyl ether group _CH2 =CH- _CH2- O-, allyl urethane group

【formula】 Allyl ester group

[Formula] Allylidene acetal group

【formula】 Acryloyl group

【formula】 methacryloyl group

[Problem that the invention seeks to solve]

While these existing photocurable resins made from combinations of polyene and polythiol compounds have excellent adhesion to metals, they also have the following drawbacks, which are major obstacles to their practical application. (a) Hard resin is difficult to obtain and remains at a semi-hard level. (b) Cured resins tend to be brittle. (c) It has a short shelf life and immediately gels when polyene and polythiol are mixed. (d) Poor heat resistance. In particular, improvements in items (a), (b), and (d) are strongly required from the viewpoint of the physical properties of the coating film. [Means for Solving the Problems] The present inventors have been studying improvements to polyene-polythiol type photocurable resins, but the above-mentioned problems cannot be solved by using the above-mentioned types as polyene compounds. It was discovered that this was difficult, and as a result of further research, an unsaturated epoxy ester obtained by reacting an epoxy resin with the reaction product of an unsaturated monoalcohol having a triple bond and a polybasic acid anhydride was found to be unsaturated. The present invention was completed based on the discovery that the system used as a saturated component exhibits properties completely different from those of ethylenically unsaturated bonds, and that the above drawbacks can be almost completely improved. That is, the present invention [] has an alkyne-type unsaturated bond and Unsaturated epoxy esters obtained by reacting an unsaturated carboxylic acid that shares a carboxyl group with an epoxy compound or resin that has two or more epoxy groups in one molecule, and [] two or more epoxy groups in one molecule. The object of the present invention is to provide a curable composition containing a polythiol compound having a thiol group (hereinafter referred to as a polythiol compound) as an active ingredient. [Function] The system using the unsaturated epoxy ester of the present invention, which has a triple bond in the molecule, provides a coating film that is incomparably harder and tougher than conventional polyenes to polythiols, and is also highly heat resistant. It becomes something. Triple bonds in unsaturated epoxy esters are essentially different from double bonds such as allyl groups. That is, when an allyl ether group is used in combination with a polythiol, the ethylenically unsaturated group acts only as a monofunctional group. However, the triple bond in the unsaturated epoxy ester of the present invention has a bifunctional ability as shown in the formula below, and as a result, it has a hardness that could not be achieved with polyene-polythiol systems having ethylenically unsaturated groups. It is presumed that it has become possible to exhibit heat resistance and heat resistance, and it has become possible to significantly improve the properties of the cured resin. The unsaturated epoxy ester of the present invention can typically be produced using propargyl alcohol as the unsaturated alcohol, phthalic anhydride as the polyhydrochloric anhydride, and an epoxy resin. , becomes as follows: (1) (2) Unsaturated epoxy ester having an alkyne-type unsaturated bond As the unsaturated monoalcohol for introducing an alkyl-type unsaturated bond, aliphatic alcohols having up to 12 carbon atoms and having a triple bond in the molecule can be used, but acetylene and Propargyl alcohol obtained by reaction with formaldehyde is representative, and is most often used in the present invention because of its ease of handling. Other compounds called acetylene alcohols can also be used as the unsaturated monoalcohol of the present invention. These compounds are synthesized by the reaction of alcohol and ketones, such as 3-methyl-1-butyn-3-ol, 3-methyl-1-butyn-3-ol,
Methyl-1-pentyn-3-ol and 3,5-
Examples include dimethyl-1-hexyn-3-ol. Furthermore, there is no triple bond at the end of the molecule, and the type is 3,6-dimethyl-4-octyne-3,
6-diol, 2,4,7,9-tetramethyl-
Examples include 5-decyne-4,7-diol and 2,5-dimethyl-3-hexyne-2,5-diol, which can of course also be used as the unsaturated alcohol of the present invention. Examples of polybasic acid anhydrides for reacting with unsaturated alcohols to form unsaturated carboxylic acids include the following types. Phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride,
Succinic anhydride, adipic anhydride, azelaic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, hettsic anhydride, trimellitic anhydride, pyromellitic anhydride. A combination of the above is also possible. Assuming that the acid anhydride corresponds to two carboxyl groups, the reaction ratio of the unsaturated monoalcohol and the polybasic acid anhydride is substantially 1 equivalent of carboxyl group to 1 equivalent of hydroxyl group. The reaction is carried out by mixing the two and stirring at 60° C. or higher for a desired period of time after dissolution. The produced unsaturated carboxylic acid does not need to be particularly purified and can be used as it is for the next reaction with the epoxy resin. Although there is no need to particularly limit the components of the epoxy resin used in the present invention, it is convenient to use commercially available epoxy resins. That is, examples of bisphenol A diglycidyl ether-based epoxy resins include those from the following companies. Dow Chemical's DER series, Ciba's GY series, Yuka Ciel's Epicote series, Toto Kasei's Epotote series, Dainippon Ink and Chemicals' Epicron series, Mitsui Petrochemical's Epomic series, Novolac's polyglycidyl ether type epoxy resins include DOW Chemical's DEN series, Ciba's ECN series, Toto Kasei's Eport YDCN-220 series, and Dainippon Ink &Chemicals' Epicron N-series. be. In addition, bisphenol F diglycidyl ether type epoxy resins, glycidyl ester type epoxy resins, polyglycol type epoxy resins, nitrogen-containing multitubular epoxy resins, cycloaliphatic epoxy resins, etc. may also be used as necessary. The reaction rate of unsaturated carboxylic acid and epoxy group is
Although the amount is substantially equivalent, about 0.9 to 1.2 equivalents of epoxy group is allowed per equivalent of carboxyl group. During the reaction, quaternary ammonium salts, triphenylphosphine, tertiary amines, etc. are used. A polymerization inhibitor is not necessarily required. Also, to avoid coloration, the reaction is carried out in a stream of non-curable gas. Since the obtained unsaturated epoxy ester resin is in the form of a viscous syrup or solid at room temperature, it is blended into the polythiol compound by heating or by dissolving it in a solvent. A low-viscosity polyene compound that reacts with polythiol can also be used in combination. One part of unsaturated monoalcohol within the range that does not impair the properties of the cured resin (for example, 50% or less is preferable)
Of course, those in which saturated monoalcohol is substituted can also be used. The polythiol compound used in the curable composition of the present invention is not particularly limited, but from a practical standpoint, an esterified product of a polyhydric alcohol and thioglycolic acid or thiopropionic acid is suitable. Examples of these compounds include, for example, pentaerythritate tetrathioglycolate, pentaerythritate tetrathiopropionate, trimethylolpropane trithiopropionate, hexanedioldithioglycolate, hexanedioldithiopropinate, bisphenol A alkylene monoepoxide adducts such as thiopropionate and thiobisphenol. The blending ratio of the unsaturated epoxy ester and the polythiol compound can be selected within a wide range, whereas good results cannot be obtained unless the double bond and thiol group are approximately 1:1 when a polyene compound is used in combination. . For example, since 1 equivalent of triple bonds in the unsaturated epoxy ester of the present invention reacts with 2 equivalents of thiol groups, originally only such a blending ratio should be good, but for 1 equivalent of triple bonds, Even when the amount of thiol group is 0.5 equivalent, a practical coating film can be obtained, and even when 2 equivalents or more is used, the physical properties of the cured coating film do not suddenly deteriorate.On the contrary, it has good adhesion to metals. Results are being obtained. Therefore, the ratio of the thiol group to 1 equivalent of triple bond may be in the range of about 0.2 to 4 equivalents, but is usually preferably used in the range of 0.3 to 3 equivalents. The curable composition of the present invention is easily cured by irradiation with energy beams such as heat, light, and electron beams. In the case of photocuring, it is necessary to use a photoreaction initiator. The amount of the initiator added is 0.01% or more, preferably 0.5 to 5%. Typical photoreaction initiators include commercially available types such as Ciba's Irgaquiure 651 (benzyl dimethyl ketal), Merck &Co.'s Darakiure 1173 (2-hydroxy-2-methylpropiophenone), 2-chlorothioxanthone, benzophenone, and benzoin. Ethers can be mentioned. In addition, a sensitizer such as amines may be used in combination, if necessary. Furthermore, it is advantageous to use a stabilizer such as polyhydric phenols or quinones in order to improve the storage stability of the combined system of an unsaturated epoxy ester having an alkyne unsaturated bond and a polythiol compound according to the present invention at room temperature. It is. The curable composition of the present invention may contain colorants, reinforcing agents, fillers, polymers, etc., if necessary. [Example] The present invention will be further explained with reference to Examples below. Example 1 Synthesis of unsaturated carboxylic acid () A separable flask equipped with a stirrer, a gas inlet tube, a reflux condenser, and a thermometer was charged with 269 g of phthalic anhydride and 112 g of propargyl alcohol, and the mixture was heated in a nitrogen gas stream. Heat to 110-120℃ for 3 hours,
Stir. From the measurement of the hydroxyl value, it was determined that the reaction was substantially completed. Add 0.1g of hydroquinone, and unsaturated carboxylic acid () (monopropargyl phthalate)
It was obtained as a slightly yellow liquid that crystallized white at 100°C. Synthesis of unsaturated epoxy ester (A) In a similar apparatus, 360 g of Dow Chemical's bisphenol A diglycigel ether type epoxy resin DER-332, 400 g of unsaturated carboxylic acid (), and trimethylbenzylammonium chloride were added as epoxy resins. Prepare 2g and place in nitrogen stream.
After reacting at 120 to 130°C for 3 hours, the acid value reached 9, so the reaction was stopped, and the reaction mixture was poured into a metal vat at 90°C and cooled. A pale yellowish brown unsaturated epoxy ester (A) was obtained which was solid at room temperature. 100 g of unsaturated epoxy ester (A), 65 g of pentaerythritate tetrathiopropionate (equivalent to 2 equivalents of thiol group per 1 equivalent of Malkin unsaturated bond), 35 g of acetone, and Merck's " Add 1.7g of Darokyur #1173”,
After making it into a uniform liquid, it was coated on a Bonderite steel plate with a bar coater to a thickness of 30 μm. After being left at room temperature overnight, it was further heated at 60° C. for 30 minutes to remove acetone, and heated at 2 m/min for 15 cm under an ultraviolet irradiation lamp with an output of 2 kW. Curing occurred in one go. The physical properties of the resulting coating film were excellent as shown in Table 1. Table 1 Hardness 2~3H Cross cut Passed Goblin adhesion test 100/100 Cigarette resistance Slightly yellowing resistant magic ink (red) Passed example 2 Synthesis of unsaturated epoxy ester (B) Stirrer, reflux condenser, thermometer, A separable flask with a gas inlet tube was filled with Dow Chemical's novolac type epoxy resin.
370 g of DEN-438, 400 g of the unsaturated carboxylic acid produced in Example 1, and 2 g of trimethylbenzylammonium chloride were charged and reacted at 120 to 130°C for 4 hours in a nitrogen gas stream, resulting in an acid value of 4.1. It got hot, so it was cooled to 90°C, 0.2g of hydroquinone was added, and the mixture was poured into a metal vat. A light reddish brown, brittle solid unsaturated epoxy ester (B) was obtained. 100 g of unsaturated epoxy ester (B), 85 g of trimethylolpropane trithiopropionate (thiol group per equivalent of Malkin unsaturated bond)
2.4 equivalents), 3.5 g of Ciba's "Irgakiyure #651" and 65 g of acetone were added as a photoinitiator, and after coating on a 35 μ thick copper foil with a bar coater to a thickness of 30 μ, the mixture was heated at 60°C. , leave it for 30 minutes, then
Under the lamp of an ultraviolet irradiation device with an output of 2kW15
cm at a speed of 2 m/min. Coating curing occurred in one pass. The physical properties of the coating are the second
As shown in the table, it showed excellent adhesion to copper foil. Table 2 Hardness 2H 180° bending 1mmφ Pass Goblin adhesion test 100/100 Cross cut Pass 260° Solder heat resistant Place it on a molten solder bath and it will swell in 30 seconds and no discoloration will occur. Example 3 Production of unsaturated carboxylic acid (2) A separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer was charged with 325 g of methyltetrahydrophthalic anhydride and 112 g of propargyl alcohol, and a stream of nitrogen gas was added. Inside 110～
When reacted at 120℃ for 3 hours, the actual hydroxyl value is 1.
The reaction was judged to have been completed because the following values were obtained. A pale yellow syrupy unsaturated carboxylic acid (2) was obtained. Synthesis of unsaturated epoxy ester (C) In a similar apparatus, Union Carbide's ERL-4221 was added as a cycloaliphatic epoxy resin at 270° C.
g, 430 g of unsaturated carboxylic acid (), and 2.5 g of triphenylphosphine, and heated to 120 g in a nitrogen gas stream.
After reacting at ~130°C for 4 hours, the acid value was 10.9. The mixture was cooled to 90°C and 0.15 g of hydroquinone was added to obtain unsaturated epoxy ester (C) in the form of a pale yellow syrup. 100g of unsaturated epoxy ester (C), 55g of pentaerythritate tetrathioglycolate (equivalent to approximately 1.6 equivalents of thiol group per equivalent of alkynic unsaturated bond), 45g of acetone, 20g of titanium white.
g, mixed, polished with #600 sandpaper, and washed with 1,1,1 trichloroethane.
After coating on a 150 ^mm × 100 ^mm × 3 ^mm steel plate to a thickness of 50 μm, the film was left at room temperature overnight to remove the acetone. Next, a scanning-type electron beam irradiation device with an output of 350 kV was used to irradiate a dose of 3 megarads. Despite being irradiated in air, the coating was completely cured in one go and exhibited the physical properties shown in Table 3. Table 3 Hardness 2H Goban adhesion test 100/100 Cross cut Pass Dew cycle weather meter After 500 hours of irradiation
Gloss retention rate: 91%, no yellowing observed. [Effects of the Invention] By using an unsaturated epoxy ester having a triple bond, the curable composition of the present invention exhibits hardness and heat resistance that could not be achieved with polyene-polythiol systems having ethylenically unsaturated groups. This makes it possible to significantly improve the properties of the cured resin.

Claims (1)

[Claims] 1 [] An unsaturated carboxylic acid that shares an alkyne-type unsaturated bond and a carboxyl group in one molecule obtained by reacting an unsaturated monoalcohol having a triple bond with a polybasic acid anhydride. and an unsaturated epoxy ester obtained by reacting with an epoxy compound or resin having two or more epoxy groups in one molecule, and a polythiol compound having two or more thiol groups in one molecule, as active ingredients. A curable composition. 2. The curable composition according to claim 1, containing 0.01 to 0.5% by weight of a photoinitiator.