TWI515233B - A hardening composition and an optical follower - Google Patents

Description

Curing composition and optical adhesive

The present invention relates to a curable composition which can be preferably used as an optical adhesive for use in producing 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 the case of the adhesive, the basic properties are adhesion, hardenability, mechanical strength, durability, and optical properties, but 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 agent has a high degree of freedom in optical design and is expected to be high. Examples of the use of an adhesive having a high refractive index include an achromatic lens formed by bonding two lenses, a composite aspheric lens composed of a composite of glass and resin, and a dichroic prism. ), etc. with complex shapes. The adhesive used in such applications requires not only a high color conversion ratio, but also adhesion, photocurability, colorless transparency, and workability to work.

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

Also, the general polyfunctional (meth) acrylate compound hardens with The shrinkage is large, and when used as an adhesive, it causes a decrease in adhesion. On the other hand, it is known that a combination of an ethylenically unsaturated compound such as a (meth) acrylate compound and a thiol composition of a thiol compound is small in shrinkage with hardening.

Patent Document 1 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 2 describes an olefin composed of MPSMA, a vinyl monomer, and a polythiol. Mercaptan composition. When demonstrated by way of example, 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 3 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 composition, and of course, it cannot provide photocurability.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2010-254732

[Patent Document 2] Japanese Patent Publication No. 03-021638

[Patent Document 3] JP-A-2005-187661

Accordingly, an object of the present invention is to provide a curable composition having a high refractive index and having properties required for an optical adhesive, which is suitable for work viscosity, low shrinkage, and colorless transparency.

The inventors of the present invention have found that the curable property of the polythiol oligomer (component A) and the ethylenically unsaturated compound (component B) obtained by reacting the episulfide compound with the thiol compound is found to be a result of a review. The composition has a workability which is suitable as an adhesive, and is suitable as an optical adhesive because it has a small shrinkage with hardening. 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 properties suitable for optical adhesives, such as viscosity, low shrinkage, and colorless transparency.

The curable composition of the present invention comprises a polythiol oligomer (component A) obtained by reacting an episulfide compound with a thiol compound, and an ethylenically unsaturated compound (component B).

First, the method for producing a polythiol oligomer (component A) is Description.

The episulfide compound which is a raw material of the polythiol oligomer is a compound having one or more episulfide groups in one molecule. In particular, when the high refractive index and crosslinkability of the curable composition are desired, the compound represented by the following formula (1) is preferred.

(wherein m is an integer of 0 to 6, n is an integer of 0 to 4, and R ¹ and R ^{2 are} each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ³ and R ^{4 are} each independently a carbon number. 1~10 alkyl group). Examples of the compound represented by the formula (1) are bis(2,3-epoxythio) sulfides and the like.

The thiol compound as a raw material of the polythiol oligomer is a compound having one or more thiol groups in one molecule, and may be any of a linear chain, a branched chain, and a cyclic group, and preferably has two molecules in one molecule. More than one thiol group polythiol compound.

In particular, when the high refractive index of the curable composition and the viscosity suitable for workability are desired, the polythiol compound represented by the following general formulae (2) to (4) is 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 ⁵ 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 ⁶ represents an alkylene group having 1 to 3 carbon atoms).

Examples of the compound represented by the formula (2) are 1,5-dimercapto-3-thiopentane, 2-mercaptomethyl-1,5-dimercapto-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 (3) 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 (4) such as hexane are exemplified by xylene dithiol or the like. By the general formula (2) to (4 The polythiol compound other than the compound represented by the formula is exemplified by ethylene glycol bis(3-mercaptopropionate), trimethylolpropane ginseng (3-mercaptopropionate), pentaerythritol bismuth (3-mercaptopropionate) , phenyldithiol, toluene dithiol, and the like.

The reaction of the episulfide compound with the thiol compound, for example, when the product is a dimer, is mainly carried out according to the following reaction formula. (wherein R and R' represent an organic group, and a and b represent an integer of 0 or more).

The thiol group reacts with a thiol group to form a secondary thiol group. The mixing ratio of the episulfide compound to the thiol compound is preferably in the range of 1.0 to 2.0 mol per mol of the thiol group. It is not preferable that the unreacted episulfide group remains after less than 1.0 mol, and the viscosity of the obtained polythiol oligomer exceeds 2.0 mol.

The reaction of the episulfide compound with the thiol compound is carried out by heating in the presence or absence of a catalyst, but a method using a catalyst is preferred. The catalyst is preferably a basic compound, an amine, an ammonium salt, a phosphine or a phosphonium salt. The amount of the catalyst used is preferably from 0.005 to 5 parts by weight, more preferably from 0.05 to 0.5 parts by weight, per 100 parts by weight of the total of the episulfide compound and the thiol compound.

The reaction of the episulfide compound with the thiol compound may be carried out in the presence of an ethylenically unsaturated compound (component B). In addition, solvents may also be used as needed. The subsequent step of distilling off the solvent when using a solvent is necessary. Reaction temperature The degree is not particularly limited, and is preferably in the range of 0 to 100 ° C, and the temperature can be slowly increased while observing the progress of the reaction. Since the reaction time is determined depending on the kind of the raw material, the mixing ratio of the episulfide compound and the thiol compound, and the reaction temperature, it cannot be specified, but it is preferably in the range of 30 minutes to 24 hours.

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

The curable composition of the present invention comprises a polythiol oligomer (component A) and an ethylenically unsaturated compound (component B).

The ethylenically unsaturated compound (component B) is a compound having two or more ethylenically unsaturated bonds 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 purifying the high refractive index of the curable composition, it is preferably a compound having an aromatic ring or a hetero ring in the molecule, and examples of the compound are triallyl isocyanurate and cyanuric acid triene. Propyl ester, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl trimellitate, tetraallyl pyromelliate, A compound represented by the formula (5), a compound represented by the formula (6), 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 s and t represent the total of s and t satisfy an integer of 0 to 4, R ⁷ represents an alkylene group having 1 to 5 carbon atoms, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom or a methyl group. ).

Examples of the compound represented by the formula (5) are 4,4'-bis(methacrylium sulfenyl)diphenyl sulfide and 4,4'-bis(methacrylium sulfenyl)diphenyl. Hey. The compound represented by the formula (6) is exemplified by 9,9-(4-(2-propenyloxyethoxy)phenyl)anthracene or the like.

The blending ratio of the component A to the component B is 1 molar with respect to the ethylenically unsaturated bond group contained in the component B, and the thiol group in the component A is preferably in the range of 0.5 to 1.5 mol, more preferably 0.8. 1.2 The scope of Moh. When the amount of the component A is less than 0.5 mol, the effect of the component A is small and it is not practical, and when it exceeds 1.5 mol, the unreacted thiol group tends to remain, which is not preferable. Further, it is understood from the reaction formula of the above-mentioned episulfide compound and the thiol compound that the total amount of the thiol group in the component A is the thiol group contained in the thiol compound used as the raw material of the polythiol oligomer. The total amount is the same.

The curable composition of the present invention is cured by heating under the presence or absence of a curing catalyst. The preferred method is exemplified by a method of using a curing catalyst, and the curing catalyst is a compound which generates a free radical such as an organic peroxide or an azo compound, or a basic compound such as an amine or a phosphine. hardening The amount of the catalyst added is preferably in the range of 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the curable composition. The polymerization temperature is preferably in the range of 0 to 150 ° C, more preferably in the range of 20 to 120 ° C, and the temperature may be slowly increased. The polymerization time is not related to various conditions such as the blending ratio of the polythiol compound and the olefinic compound, the type and amount of the curing catalyst, the weight of the curable composition, and the polymerization temperature, but it is preferably from 10 minutes to 50 minutes. The range of hours is preferably in the range of 30 minutes to 24 hours.

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 a compound are exemplified by 2,2-methoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1. -Phenylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropan-1-one, 2-benzyl-2-dimethylamino 1-(4-morpholinylphenyl)-1-butanone, bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide, 2,4,6-trimethylbenzene Mercapto-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.

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.

Regarding the viscosity of the curable composition, when it is intended to be used as an adhesive, when the viscosity is too low, the adhesive will sag, and it will be inferior to the adherend when it is bonded. 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. The viscosity suitable for workability in the present invention is also determined depending on the form of use of the adhesive method of the coating method or the bonding method, and therefore cannot be specified, but is preferably 500 to 10,000 mPa. The range of s.

[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).

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

Example 1

In a 300 ml flask, 28 g of bis(2,3-epoxypropyl) sulfide, 35 g of 1,5-diamidino-3-thiopentane, and 0.5 g of dicyclohexylmethylamine were fed, and stirring was continued at 60 ° C. 24 hours. A polythiol oligomer was produced in the above order.

37 g of triallyl isocyanurate was added to the mixture, and the mixture was stirred until homogeneous. A curable composition was produced in the above procedure.

To 100 parts by weight of the 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. The physical properties of the curable composition and the cured film are shown in Table 1.

Example 2

In a 300 ml flask, 33 g of bis(2,3-epoxypropyl) sulfide, 33 g of 1,5-dimercapto-3-thiopentane, 34 g of triallyl isocyanurate, and dicyclohexyl group were fed. Methylamine 0.5 g was continuously stirred at 60 ° C for 24 hours. 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 film are shown in Table 1.

Example 3~8

The curable composition and the cured film were produced in the same manner as in Example 2 except that the types and feed amounts of the episulfide compound, the polythiol compound, and the ethylenically unsaturated compound were changed to those shown in Table 1. The physical properties of the curable composition and the cured film are shown in Table 1.

Comparative example 1

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

A cured film was produced in the same manner as in Example 1. The physical properties of the curable composition and the cured film 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 film were produced in the same manner as in Comparative Example 1, except that the type and the 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 film 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) bis(2,3-epoxypropyl) sulfide

(b-1) 1,5-dimercapto-3-thiopentane

(b-2) 2,5-Dimercaptomethyl-1,4-dithiane

(b-3) m-xylene dithiol

(c-1) triallyl isocyanurate

(c-2) Triallyl trimellitate

(c-3) diallyl phthalate

(c-4) 4,4'-bis(methacryloylthio)diphenyl sulfide

(c-5) 2,2-bis(4-(propylene decyloxydiethoxy)phenyl)propane

Claims (6)

A curable composition comprising a polythiol oligomer (component A) obtained by reacting an episulfide compound with a thiol compound, and an ethylenically unsaturated compound (component B), and the ethylenically unsaturated compound (component B) ) is a triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, trimellitate One or more selected from the group consisting of a triallyl allyl ester, a tetraallyl pyromelliate, a compound represented by the formula (5), and a compound represented by the formula (6), (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 s and t represent that the sum of s and t satisfies an integer of 0 to 4, R ⁷ represents an alkylene group having 1 to 5 carbon atoms, R ⁸ represents a hydrogen atom or a methyl group, and R ⁹ represents a hydrogen atom or a group. base). The sclerosing composition of claim 1, wherein the episulfide compound is a compound represented by the following formula (1), (wherein m is an integer of 0 to 6, n is an integer of 0 to 4, and R ¹ and R ² each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ³ and R ⁴ each independently represent a carbon number. 1~10 alkyl group). A sclerosing composition according to claim 2, wherein the compound represented by the formula (1) is bis(2,3-epoxypropyl) sulfide. The sclerosing composition according to any one of claims 1 to 3, wherein the thiol compound is a group consisting of a compound represented by the following formula (2), formula (3), and formula (4) Group selected, (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 ⁵ 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 ⁶ represents an alkylene group having 1 to 3 carbon atoms). The curable composition according to any one of claims 1 to 3, wherein a blend ratio of the polythiol oligomer (component A) to the ethylenically unsaturated compound (component B) is relative to the component B The ethylenically unsaturated bonding group is 1 mol, and the thiol group in the component A is in the range of 0.5 to 1.5 mol. An optical adhesive comprising the curable composition according to any one of claims 1 to 3.