TWI521035B - A hardening composition and an optical follower - Google Patents

Description

Curing composition and optical adhesive

The present invention relates to a curable composition suitable as an optical adhesive used in the production of a composite optical element.

A photocurable composition containing an acrylate compound or the like as a main component has been widely used as an adhesive when an optical element is produced. In terms of the adhesive, the basic properties are adhesion, photocurability, mechanical strength, durability, and optical properties. However, in recent years, as the optical element has been highly functionalized, the refractive index has become an important performance. In particular, the high refractive index of the adhesive makes the degree of freedom in optical design wider, and therefore has high expectations. An example of the use of an adhesive having a high refractive index is, for example, a composite optical element, which is an achromatic lens formed by laminating two lenses, and a composite aspherical surface composed of a composite of glass and resin. A lens, a dichroic prism, or the like having a complicated shape. The adhesive used in such applications requires not only a high color conversion ratio, but also adhesion, photocurability, colorless transparency, heat resistance, and workability to work.

As a compound having a high refractive index, an episulfide compound containing a sulfur atom in a high concentration in a molecular structure has been found (Patent Documents 1 to 4). For example, the cured product of bis(2,3-epoxypropyl) sulfide has a refractive index of 1.70. Since the episulfide compound can be easily injected into a mold because of its low viscosity, it is suitable for the production of a molded body such as an eyeglass lens. However, if it is used as an adhesive, when the viscosity is too low, the adhesive will sag, or when it is attached. It has the problem of being misplaced with the adhesive body. Further, since the episulfide compound generally shrinks with hardening, it is a cause of a decrease in adhesion when used as an adhesive.

Further, as a polyfunctional (meth) acrylate compound having a high refractive index, 9,9-bis(4-(2-propenyloxyethoxy)phenyl) fluorene (hereinafter referred to as A-) is known. BPEF) (refractive index: 1.62), or 4,4'-bis(methacrylium sulfonyl)diphenyl sulfide (hereinafter referred to as MPSMA) (refractive index of 1.69) and the like. However, these compounds are solid at normal temperature and are therefore difficult to use alone.

Further, a general polyfunctional (meth) acrylate compound shrinks greatly as it hardens, and when used as an adhesive, it causes a decrease in adhesion.

On the other hand, it is known to combine an ethylenically unsaturated compound such as a (meth) acrylate compound with an olefin of a thiol compound. In the thiol composition, since the thiol compound contains a sulfur atom having a high atomic refractive index, a cured product having a high refractive index is obtained. However, the addition polymerization of a thiol group and an ethylenically unsaturated bond group has less crosslinking points than the chain polymerization, and the resulting thioether bond has a tendency to obtain a soft cured product, so that the obtained cured product is at a high temperature. It is easy to soften the subject. In order to obtain sufficient heat resistance, it is necessary to select a polyfunctional ethylenically unsaturated compound and a thiol compound.

Patent Document 5 describes an olefin composed of a difunctional thiol compound containing a 1,4-dithiane ring and a triallyl cyanurate or a triallyl cyanurate. Mercaptan composition. However, the refractive index of the cured product is not specifically described. And, because of the use of difunctional thiol compounds, it hardens The material is easily softened at high temperatures (refer to Comparative Example).

Patent Document 6 describes an ene thiol composition comprising A-BPEF, an ethylenically unsaturated compound, and a thiol compound. When demonstrated by the examples, the refractive index of the cured product is as high as 1.58 to 1.61.

Patent Document 7 describes an olefin composed of MPSMA, a vinyl monomer, and a polythiol. Mercaptan composition. According to an embodiment, the cured product has a refractive index of up to 1.649. However, MPSMA tends to yellow, and because of its solidity, there is a limit to the amount of dissolution of the composition.

Further, Patent Document 8 describes a resin composition comprising a resin component having an anthracene ring and a sulfur-containing compound having a diphenyl sulfide skeleton such as MPSMA, and a resin having a refractive index of 1.724 is exemplified. However, the resin composition in the invention is a thermoplastic resin obtained by kneading a polyester having an anthracene ring and a sulfur-containing compound, and is not a curable resin composition, and of course, it cannot provide photocurability.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. Hei 9-71580

[Patent Document 2] Japanese Patent Laid-Open Publication No. Hei 9-110979

[Patent Document 3] Japanese Patent Laid-Open Publication No. Hei 9-255781

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2001-163874

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2000-154251

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2010-254732

[Patent Document 7] Japanese Patent Laid-Open No. 03-021638

[Patent Document 8] Japanese Patent Laid-Open Publication No. 2005-187661

Accordingly, it is an object of the present invention to provide a hardenable composition which has a high refractive index and which also has photocurability, low shrinkage, colorless transparency, and viscosity suitable for operation as an optical adhesive. Things.

The present inventors have found that a curable composition containing a polythiol oligomer (component A) and a polyene compound (component B) obtained by reacting a polythiol with sulfur can be further developed as a result of a review of the above problems. The present invention has been completed by increasing the refractive index and having the necessary performance as an optical adhesive.

Further, the present inventors have found that a curable composition containing a polythiol oligomer (component A) obtained by reacting a polythiol with sulfur, an episulfide compound (component C), and a photobase generator (component D) has It is suitable as an adhesive for workability and has a small shrinkage with hardening, so it can be suitably used as an optical adhesive. Further, in the case of reacting a polythiol with sulfur, an alkaline catalyst is preferably used. However, when a hindered amine is used as the catalyst, it is found that a curable composition excellent in storage stability (a reaction in which the episulfide is relatively slow) can be obtained. Based on the above findings, the present invention has thus been completed.

According to the present invention, it is possible to provide a curable composition having high refractive index and also having photocurability, low shrinkage, colorless transparency, and workability as an adhesive for optical use.

The first curable composition of the present invention comprises a polythiol oligomer (component A) obtained by reacting a polythiol with sulfur and a polyene compound (component B).

First, a method for producing a polythiol oligomer (component A) will be described.

The polythiol which is a raw material of the polythiol oligomer is a compound having two or more thiol groups in one molecule, and may be any of a linear chain, a branched chain, and a cyclic group. In particular, when the high refractive index of the curable composition and the viscosity suitable for workability are desired, the compounds represented by the following general formulae (1) to (3) are preferred.

(wherein, p1 and p2 each independently represent an integer of 0 to 1, and X ₁ to X ₈ each independently represent a hydrogen atom or a methylthiol group), (wherein, q represents an integer from 0 to 3, and R ¹ represents only a bond or an alkyl group having 1 to 3 carbon atoms), (wherein, r represents an integer of 0 to 3, and R ² represents an alkylene group having 1 to 3 carbon atoms).

Examples of the compound represented by the formula (1) are 1,5-dimercapto-3-thiopentane, 2-mercaptomethyl-1,5-diindol-3-thiopentane, 2,4-double. (mercaptomethyl)-1,5-diamidino-3-thiopentane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiooctane, 4,8-bis(decylmethyl) )-1,11-dimercapto-3,6,9-trithioundecane, 4,7-bis(indolylmethyl)-1,11-dimercapto-3,6,9-trithioundecane 5,7-bis(decylmethyl)-1,11-dimercapto-3,6,9-trithioundecane, etc., and the compound represented by the formula (2) is exemplified as 2,5-di Mercapto-1,4-dithiane, 2,5-dimercaptomethyl-1,4-dithiane, 2,5-dimercaptoethyl-1,4-disulfide Examples of the compound represented by the formula (3) such as hexane are exemplified by toluene dithiol or the like. The polythiol compounds other than the compounds represented by the general formulae (1) to (3) are exemplified by ethylene glycol bis(3-mercaptopropionate), trimethylolpropane oxime (3-mercaptopropionate), pentaerythritol. Anthracene (3-mercaptopropionate), benzenedithiol, toluene dithiol, and the like.

Regarding the sulfur of the raw material of the polythiol oligomer, although sulfur forms a plurality of isotopes, it is usually preferably a generally known cyclic S8 sulfur. Sulfur can be in any form, such as crystalline, colloidal, powder or sulphur.

According to the Journal of Organic Chemistry, Vol. 32, pp. 3833-3836 (1967), the reaction of polythiol with sulfur, for example, when the product is a dimer, mainly follows the following reaction formula (6) And (7) proceed, (wherein R represents an organic group, and n represents an integer of 1 or more). The amount of sulfur used is preferably in the range of 0.2 to 0.95 mol per mol of the sulfur atom relative to 1 mol of the thiol group, more preferably in the range of 0.2 to 0.5 mol. The conversion rate of polythiol is too low to be practical when it is less than 0.2 mol, and when it exceeds 0.95 mol, it will produce a polythiol oligomer having a too large molecular weight as a raw material of an optical material, and easily leave unreacted sulfur. It is not appropriate.

The reaction of the polythiol with sulfur is carried out by heating in the presence or absence of a basic catalyst, but a method using an alkaline catalyst is preferred. The type of the basic catalyst is exemplified by an amine, an ammonium salt, a phosphine, a phosphonium salt or the like. The amount of the basic catalyst used is preferably in the range of 0.005 to 5 moles, more preferably 0.05 to 0.5 moles, per 100 moles of the thiol group contained in the polythiol of the raw material.

The order of adding the raw materials may be added to the mixed solution of the polythiol and the sulfur, or the sulfur may be added to the mixed solution of the polythiol and the catalyst, or the mixed solution of the polythiol and the catalyst may be added. It is added to a mixed solution of polythiol and sulfur. In order to allow the reaction to proceed stably, the catalyst or sulfur may be added in several portions.

The reaction of the polythiol with sulfur can also be carried out in the presence of a polyene compound (component B). The reaction of the polythiol with sulfur is accompanied by the generation of hydrogen sulfide, so it is preferably carried out under exhaust or under reduced pressure. Solvents can also be used as needed. Using solvent The subsequent step of distilling off the solvent is necessary. The reaction temperature is not particularly limited, but is preferably in the range of 0 to 100 ° C, and the temperature may be gradually increased while observing the progress of the reaction. Since the reaction time depends on various conditions such as the kind of the raw material, the ratio of the polythiol to sulfur, and the reaction temperature, it cannot be specified, but it is necessary to react until no unreacted sulfur remains.

Next, the first curable composition of the present invention will be described.

The first curable composition of the present invention comprises a polythiol oligomer (component A) and a polyene compound (component B).

The polyene compound (component B) is a compound having two or more ethylenically unsaturated bond groups in one molecule, and the ethylenically unsaturated bond group is exemplified by an acryloyl group, a methacryloyl group, a vinyl group, an allylic group. Base. In particular, when the high refractive index of the curable composition is desired, it is preferably a compound having an aromatic ring or a hetero ring in the molecule, and examples of the compound are exemplified isocyanuric cyanurate and cyanuric acid. Triallyl ester, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl trimellitate, tetraallyl pyromelliate, A compound represented by the formula (4), a compound represented by the formula (5), and the like.

(wherein X represents a sulfur atom or a sulfonyl group, and Z represents a (meth)acryloyl group, a vinyl group, or an allyl group), (wherein m and n represent the total of m and n satisfy an integer of 0 to 4, R ³ represents an alkylene group having 1 to 5 carbon atoms, R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents a hydrogen atom or a methyl group. ). Examples of the compound represented by the general formula (4) are 4,4'-bis(methacrylium sulfonyl)diphenyl sulfide and 4,4'-bis(methacrylium sulfonyl)diphenyl. The compound represented by the formula (5) is exemplified by 9,9-bis(4-(2-propenyloxyethoxy)phenyl)anthracene or the like.

The content of the polythiol oligomer in the first curable composition is preferably in the range of 10 to 80 parts by weight, more preferably 20 to 70 parts by weight, per 100 parts by weight of the curable composition. When the content of the polythiol oligomer is less than 10 parts by weight, the effect of high viscosity or low shrinkage is small, and when it exceeds 80 parts by weight, the toughness of the cured product is lowered, which is not preferable.

The curable composition of the present invention may optionally contain a polymerization inhibitor, an antioxidant, a light stabilizer (HALS), an ultraviolet absorber, a decane coupling agent, a release agent, a pigment, a dye, and the like.

The curable composition of the present invention is cured by irradiation with active light such as ultraviolet light or visible light in the presence of a radical photopolymerization initiator. The radical photopolymerization initiator is not particularly limited as long as it is free radical which generates activity by photolysis. Specific examples of such compounds are listed as 2,2-methoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholine Phenyl phenyl)-1-butanone, bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide, 2,4,6-trimethylbenzylidene-diphenyl- Phosphine oxide and the like. The radical photopolymerization initiator may be used singly or in combination of two or more. The content thereof is not particularly limited, but is preferably in the range of 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the curable composition.

When the viscosity of the curable composition is used as an adhesive, when the viscosity is too low, the adhesive will sag, or it may be offset from the adherend when it is bonded, which is not preferable. Further, when the viscosity is too high, it is difficult for the adhesive to be sprayed or applied, and it is not preferable to entrain air bubbles at the time of bonding. In the first curable composition, the viscosity suitable for workability depends on the type of adhesive used in the coating method or the bonding method, and therefore cannot be specified, but is preferably 500 to 20,000 mPa. The range of s, preferably from 1,000 to 10,000 mPa. The range of s.

The second curable composition of the present invention comprises a polythiol oligomer (component A) obtained by reacting a polythiol with sulfur, an episulfide compound (component C), and a photobase generator (component D). .

First, the method for producing the polythiol oligomer (component A) in the second curable composition is substantially as described for the first curable composition. In the following, the polythiol oligomer (component A) in the second curable composition is centered on the difference from the method for producing the polythiol oligomer (component A) in the first curable composition. The manufacturing method will be described.

In the second curable composition, the reaction of the polythiol with sulfur is carried out by heating in the presence or absence of an alkaline catalyst, but a method using an alkaline catalyst is preferred. As the alkaline catalyst, it is preferably a hindered amine. By hindered amine is meant an amine having two substituents adjacent to the amine group. The hindered amine is less active as a polymerization catalyst for the episulfide compound due to the steric hindrance of the substituent. As a result, the curable composition combining the polythiol oligomer and the episulfide compound is sufficiently stable (the polymerization of the episulfide compound is relatively slow), and can be stored for a long period of time. As the hindered amine, a compound having a 2,2,6,6-tetramethylpiperidine skeleton is preferred, specifically, 2,2,6,6-tetramethylpiperidine, 1,2,2, 6,6-pentamethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-hydroxy-1,2,2,6,6-pentamethylpiperidine, acrylic acid 2 , 2,6,6-tetramethyl-4-piperidinyl ester, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 1,2,2,6,6-five acrylic acid Methyl-4-piperidinyl ester, 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate, bis(2,2,6,6-tetramethyl-4) sebacate - piperidinyl ester), bis(1,2,2,6,6-pentamethyl-4-piperidinyl ester) and the like. The amount of the basic catalyst used is preferably in the range of 0.005 to 5 moles, more preferably 0.05 to 0.5 moles, per 100 moles of the thiol group contained in the polythiol of the raw material.

The reaction of the polythiol with sulfur can also be carried out in the presence of an episulfide compound (component C). However, when an appropriate alkaline catalyst is not selected, polymerization of an episulfide compound may occur to cause gelation. Accordingly, it is preferred to use a hindered amine for the above reasons when using an alkaline catalyst.

Next, the second curable composition of the present invention will be described.

The second curable composition of the present invention contains the above-mentioned polythiol oligomer (component A), an episulfide compound (component C), and a photobase generator (D The composition of the sub-).

The episulfide compound (component C) is a compound having one or more episulfide groups in one molecule. In particular, when the high refractive index of the curable composition is desired, the compound represented by the following formula (8) is preferred: (wherein m is an integer of 0 to 6, n is an integer of 0 to 4, and R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁵ and R ⁶ each independently represent a carbon number. 1~10 alkyl group). Examples of the episulfide compound represented by the formula (8) are bis(2,3-epoxypropyl) sulfide and the like.

The episulfide compound represented by the general formula (8) shrinks greatly as it hardens, but shrinkage due to hardening can be suppressed by copolymerization with a polythiol oligomer. Further, the episulfide compound represented by the formula (8) has a substantially low viscosity, but is mixed with a polythiol oligomer to adjust the viscosity to be excellent in workability.

The second curable composition is related to the viscosity of the curable composition, and when it is intended to be used as an adhesive, when the viscosity is too low, the adhesive will sag and will be offset from the substrate during bonding. Not good. Further, when the viscosity is too high, the ejection or coating of the adhesive becomes difficult, and it is not preferable to entrain air bubbles at the time of bonding. The viscosity of the second curable composition suitable for workability depends on the application method of the coating method or the bonding method, and therefore cannot be specified, but is preferably 100 to 50,000 mPa. The range of s is preferably 500~10,000 mPa. The range of s.

The content of the polythiol oligomer in the second curable composition is preferably in the range of 10 to 70 parts by weight, more preferably 20 to 50 parts by weight, per 100 parts by weight of the curable composition. When the content of the polythiol oligomer is less than 10 parts by weight, the effect of high viscosity or low shrinkage is small, and when 70 parts by weight or more, the toughness of the cured product is not preferable.

The photobase generator (component D) is a compound which generates a base by photodecomposition using active light. In particular, since the polymerization of the episulfide compound is promoted by using DBN (diazabicyclononene) or DBU (diazabicyclononene) or the like, it is preferred to produce a photobase generator which produces such a base. Specifically, it is exemplified by the fluorenone forming a tetraaryl borate described in JP-A-2001-513765 (the left side of the following formula (9)), or the aryl group described in JP-A-2005-511536. An alkyl-substituted 1,3-diamine (to the left of the following formula (10)) or the like. These may be used singly or in combination of two or more. The amount of the photobase generator to be added is preferably from 0.01 to 10 parts by weight, more preferably from 0.1 to 5 parts by weight, per 100 parts by weight of the curable composition.

Further, a photosensitizer may be contained in addition to the photobase generator. By adding The light sensitizer accelerates the photolysis of the photobase generator, thereby shortening the hardening time of the photocurable composition. Specific examples of the photosensitizer are benzophenones, thioxanthones, anthraquinones, camphorquinones, benzils, Michael ketones, anthraquinones. class. These may be used singly or in combination of two or more. The amount of the photosensitizer added is preferably in the range of 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the curable composition.

A polymerization inhibitor, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a decane coupling agent, a mold release agent, a pigment, a dye, etc. may be added to the said hardening composition as needed. In addition, it is also possible to perform filtration or defoaming as needed.

[Examples]

The invention will be specifically described below by way of examples, but the invention is not limited thereto. Further, the curing shrinkage ratio in the examples was calculated from the refractive index before and after curing according to the following calculation formula.

X=(1-d1/d2)×100[%]

R=(n ² -1)/(n ² +2)×M/d

The R/M before and after hardening is constant, so from the above two formula, X=[1-{(n1 ² -1)/(n1 ² +2)}/{(n2 ² -1)/(n2 ² +2) }]×100[%] (wherein X represents the hardening shrinkage ratio, d represents the specific gravity, d1 represents the specific gravity before hardening, d2 represents the specific gravity after hardening, R represents molecular refraction, n represents refractive index, and n1 represents before hardening. The refractive index, n2 represents the refractive index after hardening, and M represents the molecular weight).

Moreover, the viscosity of the hardenable composition is a cone-plate type viscometer (cone/plate viscometer) DV-II+ (manufactured by Brookfield Co., Ltd.), measured at a temperature of 25 °C. The refractive index of the curable composition and the cured product (cured film) was measured using an Abbe refractometer NAR-3T (manufactured by ATAGO Co., Ltd.). The transmittance of the cured product was measured using a spectrophotometer U-3500 (manufactured by Hitachi High-Technologies Corporation) at a thickness of 0.25 mm and a wavelength of 400 nm.

First, an embodiment of the first hardenable composition will be described below.

Example 1

Into a 300 ml flask, 65 g of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiooctane and 0.05 g of dicyclohexylmethylamine were fed, and the mixture was thoroughly stirred. 4.7 g of sulfur powder was slowly added dropwise several times at room temperature. When the sulfur powder is added, the solution turns yellow and a gas is generated. After the generation of the gas was moderated, the nitrogen gas was passed through the liquid surface to raise the temperature to 60 ° C and stirring was continued for 3 hours. As the reaction progresses, the gas is almost no longer produced and the solution becomes colorless and transparent. A polythiol oligomer was produced in the above order.

After the polythiol oligomer was cooled to room temperature, 35 g of triallyl cyanurate was added and stirred until uniform. The first curable composition was produced in the above procedure.

To 100 parts by weight of the first curable composition, 3 parts by weight of 1-hydroxy-cyclohexyl phenyl ketone was added, and stirred until uniform, and defoamed under reduced pressure. The two sheets were subjected to mold release treatment, and the light was irradiated from a metal halide lamp (120 W/cm) for 3 minutes from a distance of 30 cm, and then the cured film was peeled off from the glass plate. A cured film having a thickness of 0.25 mm was produced in the above procedure. Sclerosing The physical properties of the composition and the cured film (cured material) are shown in Table 1.

Example 2~5

The first curable composition and the cured product were produced in the same manner as in Example 1 except that the types and feed amounts of the polythiol, sulfur, and polyene compound were changed to those shown in Table 1. The physical properties of the first curable composition and the cured film (cured material) are shown in Table 1.

Comparative example 1

55 g of 2,5-dimercaptomethyl-1,4-dithiane and 45 g of triallyl cyanurate were fed into a 300 ml flask and stirred until uniform. A curable composition was produced in the above procedure.

The production of the cured film was carried out in the same manner as in Example 1. The physical properties of the curable composition and the cured product are shown in Table 2. Also, compared with the embodiment, the value of the poor performance is added to the bottom line.

Comparative example 2~4

The curable composition and the cured product were produced in the same manner as in Comparative Example 1, except that the type and amount of the thiol compound and the ethylenically unsaturated compound were changed to those shown in Table 2. The physical properties of the curable composition and the cured product are shown in Table 2. Also, compared with the embodiment, the value of the poor performance is added to the bottom line.

Abbreviated description in the table

(a-1) 4-mercaptomethyl-1,8-dimercapto-3,6-dithiooctane

(a-2) 2,5-dimercaptomethyl-1,4-dithiane

(a-3) m-xylene dithiol

(a-4) 1,5-dimercapto-3-thiopentane

(b-1) Triallyl isocyanurate

(b-2) 4,4'-bis(methacryloylthio)diphenyl sulfide

(b-3) Triallyl trimellitate

(b-4) 2,2-bis(4-(propylene decyloxydiethoxy)phenyl)propane

Next, an example of the second curable composition will be described below.

Example 6

40 g of 2,5-dimercaptomethyl-1,4-dithiane and 0.05 g of tributylamine were fed into a 300 ml flask and stirred well. 6.0 g of sulfur powder was slowly added dropwise several times at room temperature. When the sulfur powder is added, the solution turns yellow and a gas is generated. After the generation of the gas was moderated, the nitrogen gas was passed through the liquid surface to raise the temperature to 60 ° C and stirring was continued for 3 hours. As the reaction progresses, the gas is almost no longer produced and the solution becomes colorless and transparent. A polythiol oligomer was produced in the above order.

To the polythiol oligomer (component A), 60 g (component C) of bis(2,3-epoxythiopropyl) sulfide and 0.2 g of a photobase generator represented by the following structural formula (11) were added. Ingredients) and 1 g of 4-benzylidene-4'-methyldiphenyl sulfide as a sensitizer, and stirred until uniform.

The second curable composition was produced in the above procedure. The viscosity of the hardening composition is 900 mPa. s (20 ° C). Further, after storage for one week at 5 ° C, the curable composition gelatinized.

The hardened composition was sandwiched between two glass plates subjected to mold release treatment, and the light of the metal halide lamp (120 W/cm) was irradiated from a distance of 30 cm for 3 minutes, and then the hardened film was peeled off from the glass plate. A cured film having a thickness of 0.25 mm was produced in the above procedure.

The physical properties of the second curable composition and the cured film are shown in Table 3.

Example 7

Feeding 4,5-dimercaptomethyl-1,4-dioxane 40 g, bis(2,3-epoxypropyl) sulfide 60 g, methacrylic acid 1,2,2 in a 300 ml flask , 6,6-pentamethyl-4-piperidinyl ester 0.1 g, and stirred well. 6.0 g of sulfur powder was slowly added dropwise several times at room temperature. When the sulfur powder is added, the solution turns yellow and a gas is generated. After the generation of the gas was moderated, the nitrogen gas was passed through the liquid surface to raise the temperature to 60 ° C and stirring was continued for 3 hours. As the reaction progresses, the gas is almost no longer produced and the solution becomes colorless and transparent. After cooling to room temperature, 0.2 g of the photobase generator represented by the above formula (11) (component D) and 4-benzylidene-4'-methyldiphenyl sulfide as a sensitizer were added. 1g, stir until uniform. A curable composition was produced in the above procedure. The viscosity of the hardening composition is 1,000 mPa. s (20 ° C). Moreover, the viscosity after storage for one week at 5 ° C is 1,100 mPa. s (20 ° C).

Production of a cured product was carried out in the same manner as in Example 6. The physical properties of the second curable composition and the cured film are shown in Table 3.

Example 8~14

In addition to changing the type and feed amount of thiol compounds, sulfur and episulfide compounds Further, in the same manner as in Example 7, except for the contents shown in Tables 3 and 4, a second curable composition and a cured product were produced. The physical properties of the second curable composition and the cured product are shown in Tables 3 and 4.

Comparative Example 5

100 g of bis(2,3-epoxythio) sulfide, 0.2 g of a photobase generator represented by the above structural formula (9) (component D), and 4-benzylidene-4 as a sensitizer 1 g of '-methyldiphenyl sulfide, and stirred until uniform. A curable composition was produced in the above procedure.

A cured product was produced in the same manner as in Example 6. The physical properties of the curable composition and the cured product are shown in Table 5. Further, compared with the embodiment, the poor physical property is filled with the bottom line.

Comparative Example 6

20 g of 2,5-dimercaptomethyl-1,4-dithiane, 80 g of bis(2,3-epoxythio) sulfide, and a photobase generator represented by the above structural formula (9) 0.2 g (component D) and 1 g of 4-benzylidene-4'-methyldiphenyl sulfide as a sensitizer were stirred until uniform. A curable composition was produced in the above procedure.

A cured product was produced in the same manner as in Example 6. The physical properties of the curable composition and the cured product are shown in Table 5. Further, compared with the embodiment, the poor physical property is filled with the bottom line.

Abbreviated description in the table

(a'-1) 2,5-dimercaptomethyl-1,4-dithiane

(a'-2) m-xylenedithiol

(a'-3) 1,5-dimercapto-3-thiopentane

(b'-1) tributylamine

(b'-2) 1,2,2,6,6-pentamethyl-4-piperidinyl methacrylate

(c-1) bis(2,3-epoxypropyl) sulfide

Claims (9)

A curable composition comprising a polythiol oligomer (component A) obtained by reacting a polythiol with sulfur and a polyene compound (component B), or a polythiol obtained by reacting a polythiol with sulfur An oligomer (component A), an episulfide compound (component C), and a photobase generator (component D). The sclerosing composition of the first aspect of the invention, wherein the polythiol is one or more selected from the group consisting of the following general formula (1), the following general formula (2), and the following general formula (3); , (wherein, p1 and p2 each independently represent an integer of 0 to 1, and X ₁ to X ₈ each independently represent a hydrogen atom or a methylthiol group), (wherein q represents an integer from 0 to 3, and R ¹ represents only a bond or a C 1 to 3 alkyl group), (wherein, r represents an integer of 0 to 3, and R ² represents an alkylene group having 1 to 3 carbon atoms). The sclerosing composition of claim 1 or 2, wherein the ratio of the polythiol to sulfur when reacting the polythiol with sulfur is 0.2 to 0.95 mol per mol of the thiol group. The scope. A sclerosing composition according to claim 1 or 2, wherein the polyene compound (component B) is a triallyl cyanurate, a triallyl cyanurate or a diene phthalate. Propyl ester, diallyl isophthalate, diallyl terephthalate, triallyl trimellitate, tetraallyl pyromelliate, a compound represented by the formula (4), One or more selected from the group consisting of compounds represented by the formula (5), (wherein X represents a sulfur atom or a sulfonyl group, and Z represents a (meth)acryloyl group, a vinyl group, or an allyl group), (wherein m and n represent the total of m and n satisfy an integer of 0 to 4, R ³ represents an alkylene group having 1 to 5 carbon atoms, R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents a hydrogen atom or a methyl group. ). A sclerosing composition according to claim 1 or 2, which uses a hindered amine as a reaction catalyst for the reaction of a polythiol with sulfur. A sclerosing composition according to claim 5, wherein the hindered amine is a compound having a 2,2,6,6-tetramethylpiperidine skeleton. The sclerosing composition according to claim 1 or 2, wherein the episulfide compound (component C) is a compound represented by the following formula (8), (wherein m is an integer of 0 to 6, n is an integer of 0 to 4, and R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁵ and R ⁶ each independently represent a carbon number. 1~10 alkyl group). The sclerosing composition of claim 7, wherein the compound represented by the formula (8) is bis(2,3-epoxypropyl) sulfide. An optical adhesive comprising the curable composition according to any one of claims 1 to 8.