JPH0364531B2 - - 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 polyene 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 base

[Formula] arylideneacetate tar group

[Formula] Acrylic loyl group

[Formula] Methacryloyl group

[Formula] is mentioned. Polythiol compounds are generally mainly esters of polyhydric alcohols and carboxylic acids containing thiol groups. The above-mentioned composition is cured by so-called H-transfer polymerization (hereinafter referred to as "initiator") when irradiated with energy rays (ultraviolet rays, electron beams, etc.) in the presence of a photoreaction initiator (hereinafter simply referred to as "initiator"). (described as “light curing”). However, in the case of electron beams, an initiator may not be necessary. [Problems to be Solved by the Invention] Although these existing photocurable resins made from a combination of polyene and polythiol compounds have excellent adhesion to metals, they also have the following drawbacks, and their practical use is limited. This has become a major hindrance to the development of society. (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 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, a system using a monoalcohol having a triple bond as an unsaturated component showed properties completely different from those of ethylenically unsaturated bonds, and could almost satisfy the above drawbacks. The present invention was completed based on the discovery that the present invention can be improved. That is, the present invention [] contains two or more alkyne-type unsaturated alcohols in one molecule, which are obtained by reacting an alcohol sharing a triple bond and a hydroxyl group (hereinafter referred to as an unsaturated alcohol) with a polyhydric isocyanate. Unsaturated urethane compounds or oligomers having saturated bonds (hereinafter referred to as unsaturated urethane compounds), and polythiol compounds having two or more thiol groups in one molecule (hereinafter referred to as polythiol compounds). It is an object of the present invention to provide a curable composition having an active ingredient. [Function] A system using an unsaturated urethane compound obtained by reacting an unsaturated alcohol with a polyvalent isocyanate provides a coating film that is much harder and tougher than conventional polyenes to polythiols, and has excellent heat resistance. It will also be rich in sexuality. The triple bond of unsaturated alcohols is essentially different from the double bond of allyl groups. That is, when allyl ether group is used in combination with polythiol,
Ethylenically unsaturated groups act only monofunctionally. However, the triple bond of unsaturated alcohol has a bifunctional ability as shown in the formula below, and as a result, it exhibits hardness and heat resistance that could not be achieved with polyene-polythiol systems that have ethylenically unsaturated groups. It is presumed that this has made it possible to significantly improve the properties of the cured resin. The unsaturated urethane compound [ ] of the present invention can typically be produced using propargyl alcohol as the unsaturated alcohol and tolylene diisocyanate as the polyvalent isocyanate. , becomes as follows: Unsaturated urethane compound having an alkyne-type unsaturated bond [] As the unsaturated alcohol for introducing an alkyne-type unsaturated bond, aliphatic alcohols having up to 12 carbon atoms and having a triple bond in the molecule can be used, but acetylene Propargyl alcohol obtained by reacting alcohol with formaldehyde is typical, and is most often used in the present invention because of its ease of handling. Other compounds, so-called acetylene alcohols, can also be used as the unsaturated alcohols 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-pentan-3-ol, and 3,5-dimethyl-3-ol. Examples include 1-hexyn-3-ol and the like. Furthermore, as a type without a triple bond at the end of the molecule, 3,6-dimethyl-4-octyl-3,6-
Diol, 2,4,7,9-tetramethyl-5-
Examples include decine-4,7-diol and 3,5-dimethyl-3-hexyne-2,5-diol, which can of course also be used as the unsaturated alcohol of the present invention. Examples of polyvalent isocyanates that react with unsaturated alcohols include the following. Tolylene diisocyanate (2,4,
2,6), xylylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, paraphenylene diisocyanate, hexamethylene diisocyanate, hydrogenated diphenyl Methane diisocyanate, 1,5-naphthylene diisocyanate. For isocyanates whose reaction products crystallize at room temperature when reacted with unsaturated alcohols, it is practical to use a small amount of polyhydric alcohol in combination to prevent crystallization. It is suitable that the reaction ratio between the hydroxyl group and the isocyanate group of the unsaturated alcohol is substantially 1:1, but it can be practically used in the range of 0.8:1.2 to 1.2:0.8. Of course, it is also possible to use a resin in which a portion (for example, 50% or less is preferable) of the unsaturated alcohol is replaced with a saturated alcohol within a range that does not impair the properties of the cured resin. 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, hexanedioldithiopropionate, bisphenol. Examples of the alkylene monoepoxide adducts of A include thiopropionate and thiobisphenol. The blending ratio of the unsaturated urethane compound and the polyol compound can be selected within a wide range, whereas when a polyene compound is used in combination, good results cannot be obtained unless the ratio of double bond and thiol group is approximately 1:1. . For example, a practical coating film can be obtained even if the amount of thiol group is 0.5 equivalent per equivalent of triple bond,
Even when 2 equivalents or more were used, no phenomena such as rapid deterioration of the physical properties of the cured coating film were observed, and on the contrary, good results were obtained in terms of adhesion to metals. 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 urethane having an alkyne unsaturated bond and a polythiol compound according to the present invention at room temperature. be. 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 (hereinafter simply referred to as "examples" unless otherwise specified). Example 1 Synthesis of unsaturated urethane compound [A] having an alkyne unsaturated group Propargyl alcohol was added to a 13-neck flask equipped with a stirrer, a reflux condenser and a thermometer.
112g (2 moles), isophorone diisocyanate
222 g (1 mole), 166 g of methyl ethyl ketone, and 1 g of dibutyltin dilaurate were charged, cooled so as not to exceed 65°C, and then reacted at 60°C for 5 hours. As a result of infrared analysis, free isocyanate groups disappeared. was recognized. A pale yellow liquid unsaturated urethane compound [A] (methyl ethyl ketone solution) was obtained. 100 parts by weight of unsaturated urethane compound [A], 95 parts by weight of pentaerythritate tetrathiopropionate, 0.1 part by weight of parabenzoquinone, and 3 parts by weight of Merck's Dalquiure 1173 as an initiator were mixed;
Melted and bonderite treated steel plate for coating test
It was coated with a bar coater to a thickness of 100μ.
After leaving it at 80℃ for 30 minutes to volatilize the methyl ethyl ketone, it was placed under an ultraviolet irradiation device with an output of 2 kilowatts.
10 cm was passed at a speed of 5 m/min. Coating curing occurred in one pass. The physical properties of the coating after repeated passes five times are shown in Table 1 below. Table 1 Hardness (pencil) 2-3H Goblin adhesion test 100/100 Cross-cut test Pass 90° bending Cigarette resistance with no abnormalities in the coating film Slight yellowing but no abnormalities in the coating film. Example 2 (Comparative Example) Using 116 g of allyl alcohol in place of propargyl alcohol in Example 1, an unsaturated urethane compound [B] having an ethylenically unsaturated group was synthesized under the same conditions. Example 1 was carried out using a system in which 100 parts by weight of the obtained unsaturated urethane compound [B] was mixed with 50 parts by weight of pentaerythritate tetrathiopropionate, 0.08 parts by weight of parabenzoquinone, and 2.7 parts by weight of Darocyur 1173 from Merck & Co. Painted and cured in the same manner. Coating curing occurred in one pass. However, the physical properties of the coating film were as shown in Table 2, and were not as good as those of Example 1. Table 2 Hardness (Pencil) F-B Goblin adhesion test 39/100 Cross-cut test 90° bending with peeling Cigarette resistance with no abnormalities in the paint film Discoloration to dark brown and small cracks in the paint film. Example 3 Synthesis of unsaturated urethane compound [C] having an alkyne unsaturated group 1. Into a separable flask, 174 g of 2,4-tolylene diisocyanate, 45 g of trimethylolpropane and 80 g of methyl ethyl ketone were charged.
After reacting at .degree. C. for 8 hours, infrared analysis showed that the absorption of isocyanate groups was reduced by half. Next, 56 g of propargyl alcohol and 0.6 g of dibutyltin dilaurate were added and reacted at the same temperature for 3 hours. As a result of infrared analysis, it was found that the absorption of isocyanate completely disappeared. Unsaturated urethane compound [C] was obtained in the form of a dark yellow liquid. To 100 parts by weight of unsaturated urethane compound [C], 60 parts by weight of trimethylolpropane trithioglycolate and 2 parts of Ciba's Irgakiure 651 as an initiator were added, and the mixture was placed on a Bonderite steel plate in the same manner as in Example 1.
It was coated with a bar coater to a thickness of 50μ. After being left at 80° C. for 30 minutes, irradiation was performed using the irradiation device used in Example 1 under the same conditions. Paint film curing is 1
It happened in transit. The physical properties of the resulting coating film are shown in Table 3, and it was tough and had good adhesion. Table 3 Hardness (pencil) H Gobun adhesion test 100/100 Cross cut test Pass 90° bending 50mmφ180° bending with no abnormalities in the coating Same example 4 (composition curing example) Unsaturated used in example 1 A mixture of urethane compound [A] and pentaerythritate tetrathiopropionate was painted on a Bonderite steel plate to a thickness of 50μ, and after removing the solvent at 80℃ for 30 minutes, an energy output of 350 kilovolts and a scanning type. A dose of 3 megarads was irradiated using an electron beam irradiation device. Although the irradiation was carried out in air rather than in an inert gas stream, the coating was completely cured and its physical properties were as listed in Table 4. Table 4 Hardness (pencil) 2-3H Goblin adhesion test 100/100 Cross-cut test Pass 90° bending Cigarette resistance with no abnormality in the coating film Slight yellowing, but no abnormality in the coating film. Example 5 Unsaturated urethane with alkyne unsaturated bond
Synthesis of (D) 3-Methyl-1-butyl-3-ol [Air Products &
Manufactured by Chemicals (product name: Orphine B)] 168
g, isophorone diisocyanate 222g, methyl ethyl ketone 110g, dibutyltin dilaurate 1.2
When reacted for 8 hours in a nitrogen stream at 60°C, infrared analysis showed that all free isocyanate groups had disappeared. A slightly yellowish unsaturated urethane (D) was obtained in methyl ethyl ketone solution. A solution of unsaturated urethane (D) in methyl ethyl ketone
To 100 parts by weight and 120 parts by weight of hexanediol dithiopropionate, 4 parts by weight of Dalokyur 1173 and 0.1 part by weight of hydroquinone were added as a photoreaction initiator, and the mixture was placed on a 35 μm thick copper foil to a thickness of 30 μm. It was applied with a bar coater. After being left overnight, the solution was heated at 60° C. for 30 minutes to remove the solvent, and passed at 2 m/min 15 cm below the lamp of an ultraviolet irradiation device with an output of 2 kW. Curing occurred in one pass. The physical properties of the obtained coating film are as shown in Table 5.
It showed excellent adhesion to copper foil. Table 5 Hardness (Pencil) H Gobun adhesion test 100/100 Cross cut test Passed 180゜1mmφ Bending test No abnormalities in the coating film Resistance to 260°C solder heat After leaving it on a molten solder bath for 30 seconds, the appearance is as follows. I will not admit it. Example 6 (composition curing example) After coating the mixture of the unsaturated urethane compound (A) and pentaerythritate tetrathiopropionate used in Example 1 to a thickness of 10μ on a 35μ thick copper foil. , 60℃ for 30 minutes, 80℃ for 30 minutes, then 150℃
I baked it for 2 hours. The coating film at room temperature was completely cured, and its physical properties showed excellent adhesion to copper as shown in Table 6. Table 6 Hardness (Pencil) 2~3H Goblin adhesion test 100/100 Cross cut test Passed 180゜1mmφ Bending test No abnormalities in the coating film Resistance to 260℃ solder heat Although it will swell if left on a molten solder bath for 30 seconds. , no cracks were observed. [Effects of the invention] By using the unsaturated urethane compound [I] in the curable composition, it becomes possible to exhibit hardness and heat resistance that could not be achieved with polyene-polythiol systems having ethylenically unsaturated groups. , can significantly improve the properties of the cured resin.

Claims (1)

[Claims] 1 [] An unsaturated compound having two or more alkyne-type unsaturated bonds in one molecule, obtained by reacting an unsaturated alcohol that shares a triple bond and a hydroxyl group with a polyhydric isocyanate. A curable composition containing as active ingredients a urethane compound or oligomer, and a polythiol compound having two or more thiol groups in one molecule. 2. The curable composition according to claim 1, containing 0.01 to 0.5% by weight of a photoinitiator.