WO2025028355A1 - Highly refractive radical-polymerizable composition including sulfide compound - Google Patents

Abstract

[Problem] To provide a radical-polymerizable composition that is used as a transparent resin source material suited for optical applications, wherein the radical-polymerizable composition not only has superior curability, but also has a low viscosity and a high refractive index, and the refractive index of a polymer that is obtained by curing the same can be adjusted. [Solution] A radical-polymerizable composition including: (A) a vinyl sulfide compound that has a heterocycle and is represented by general formula (1); an aryl sulfide compound that is represented by general formula (5); and (C) a radical polymerization initiator, said radical-polymerizable composition being characterized in that the refractive index (n_D) at 25°C is 1.60 or greater.

Description

Highly refractive radically polymerizable composition containing a sulfide compound

The present invention relates to a highly refractive radically polymerizable composition containing a sulfide compound and a polymer thereof.

In recent years, displays using liquid crystal or organic electroluminescence (EL) have come into widespread use, and the surfaces of these displays are covered with a laminate of multiple layers of optical films, providing functions such as light extraction and touch panel functionality. The substrates used are also shifting from glass substrates to flexible substrates using resin, and various film laminates are used for sealing. In these displays, controlling the light from the outside and the light emitted from the inside is extremely important in terms of display quality.

On the other hand, these film laminates each have a different refractive index for light, and the difference in refractive index can result in various characteristics or problems. For example, in a color filter, if the pigment type is different, the pixels will have different refractive indices, which can cause problems such as increased light scattering at the interface with the overcoat layer and loss of transmitted light. In addition, film laminates are generally bonded with an adhesive composition, but it is known that if a general acrylic adhesive is used to bond high refractive index materials, reflections will occur at the interface due to the difference in refractive index between the two. For this reason, there are known examples in which a refractive index adjuster is used to adjust the refractive index of the adhesive. For example, in Patent Document 1, a compound having a triazine ring is added to an acrylic polymer to develop an adhesive with a high refractive index of 1.55 or more.

In addition, when a gas barrier film is used to protect the surface of a display, there are two interfaces with the plastic substrate, the evaporated thin film layer, and the gas barrier coating layer, so color unevenness occurs due to interference light, which is a problem in appearance. In general, when two films are laminated, the greater the difference in refractive index, the greater the reflection at the contact surface of the films, which is thought to cause problems with light extraction. Therefore, methods to reduce the difference in refractive index between the laminated films are being considered. For example, in touch panels, etc., films patterned with a metal oxide called ITO (Indium Tin Oxide), which transmits visible light, are used, but since this ITO is an inorganic material, it has a higher light reflectance than organic materials, and there is a problem that the ITO pattern becomes visible because the reflectance of the ITO surface and the substrate film (PET) differs. In this way, resin films generally have a low refractive index, and attempts to increase the refractive index of the film are being considered. For example, Patent Document 2 discloses a polymerizable composition that does not contain a (meth)acrylate compound having a triazine skeleton and a refractive index adjuster, and by using a (meth)acrylate compound having a fluorene skeleton as the refractive index adjuster, a cured product is obtained that has a refractive index at 589 nm of 1.557 or more and 1.571 or less. As such, there is a demand for a refractive index adjuster that can increase the refractive index of existing polymerizable compositions.

In general, there is a positive correlation between the refractive index of a film and the refractive index of the polymerizable composition that is its raw material, and in order to obtain a polymer with a high refractive index, the polymerizable compound that makes up the polymerizable composition must have a high refractive index. Therefore, it is thought that a high refractive index can be achieved by adding a polymerizable compound with a high refractive index that can be copolymerized with existing polymerizable compounds.

As a method for increasing the refractive index of a polymerizable compound, it is already widely known to introduce an aromatic ring into the molecular structure, or to introduce a halogen atom (excluding fluorine) or a sulfur atom. For example, as a polymerizable compound having an aromatic ring in the molecular structure, in addition to a benzene ring, those having a polycyclic aromatic ring such as biphenyl, naphthalene, fluorene, and anthracene are known. However, a polymerizable compound having a single benzene ring in the molecular structure does not have a sufficient refractive index. In addition, although a polymerizable compound having a polycyclic aromatic ring such as biphenyl, naphthalene, fluorene, and anthracene in the molecular structure is expected to have a high refractive index, in most cases it becomes a high-viscosity liquid or crystalline solid, and there is a problem that handling properties such as solubility are reduced. For example, Patent Document 3 discloses a composition containing a (meth)acrylate having a fluorene skeleton as a curable composition that can obtain a cured product with a high refractive index and a low Abbe number. Among them, 9,9-bis(4-(2-acryloyloxyethoxy)phenyl)fluorene has a refractive index nD of 1.608 and a viscosity at 25°C of 100,000 mPa·s or more.

Furthermore, monomer compositions containing sulfur atoms with high intrinsic refractive index have also been reported. For example, in Patent Document 4, an aromatic ring is introduced via a sulfur atom to increase the refractive index. Patent Document 5 discloses a polymerizable composition mainly composed of a thio(meth)acrylate monomer, and bis[(4-methacryloylthio)phenyl]sulfide and the like are disclosed. Patent Document 6 discloses a compound containing a methylthiophenyl group as a new (meth)acrylic acid ester for dilution, which has low viscosity, high refractive index, and high heat resistance of its homopolymer. Patent Document 7 discloses a polymerizable composition that uses a sulfide compound and a (meth)acrylate compound containing a sulfur compound as a liquid curable ink composition that can form a cured product with a high refractive index and is applicable to the inkjet method, and uses zirconium oxide nanocrystals as the metal compound nanocrystals.

Furthermore, Patent Document 8 discloses a (meth)acrylic acid ester having a condensed ring selected from the group consisting of a naphthalene ring, an anthracene ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a fluorene ring, and a phenanthrene ring, as a polymerizable compound having a high refractive index, high solubility in a polymerizable compound having an aromatic ring, and high visible light transmittance of the cured product. Patent Document 9 discloses a (meth)acrylic acid ester having an aryl group or a heteroaryl group as a method for producing a high refractive index symmetrical (meth)acrylic acid ester, and a compound having a mercaptobenzothiazole group as the heteroaryl group. Similarly, Patent Document 10 discloses a (meth)acrylic acid ester compound having a benzothiazole ring as a sulfur atom-containing (meth)acrylic acid ester. However, all of these acrylic esters having a high refractive index have the problem of high viscosity.

Furthermore, Patent Document 11 discloses a compound in which an aromatic ring or aromatic heterocycle is introduced into three of the four molecular chains of a quaternary carbon of a pentaerythritol skeleton, and a (meth)acrylic group is introduced into the remaining one. As the aromatic heterocycle, a benzoxazole ring, a thienoxazole ring, a thiazolooxazole ring, an oxazolooxazole ring, an oxazoloimidazole ring, an oxazolopyridine ring, an oxazolopyridazine ring, an oxazolopyrimidine ring, an oxazolopyrazine ring, a naphthoxazole ring, a quinolinoxazole ring, a dioxazolopyrazine ring, a phenoxazine ring, a benzothiazole ring, a furothiazole ring, a thienothiazole ring, a thiazolothiazole ring, a thiazoloimidazole ring, a thienothiadiazole ring, a thiazolothiadiazole ring, a thiazolopyridine ring, a thiazolopyridazine ring, a thiazolopyrimidine ring, a thiazolopyrazine ring, a naphthothiazole ring, a quinolinothiazole ring, and a phenothiazine ring are disclosed. Among them, a thiazolothiadiazole ring is disclosed.

However, most of these high refractive index polymerizable compounds have an acrylic acid ester structure. By using acrylic acid ester, transparency and high polymerizability can be expected. However, on the other hand, there is a drawback in that the viscosity becomes high. For example, Patent Document 12 discloses a high refractive index monomer that can be cured with ultraviolet light and is useful for manufacturing optical articles, particularly light control films, and among them, as a heterocyclic (meth)acrylate, a meth)acrylate having a benzothiazole group is disclosed. It is described that the refractive index of 1,3-bis(2-mercaptobenzothiazoyl)propan-2-yl acrylate is 1.629 and the viscosity is 860 cP, and that the refractive index of 2-(4-chlorophenoxy)-1-[(phenylthio)methyl]ethyl acrylate is 1.5792 and the viscosity is 352 cP.

On the other hand, in recent years, when these high refractive index polymerizable compounds are used in optical applications such as displays, it is considered promising to use them in coating methods such as inkjet printing, and low viscosity is also required as an important factor for polymerizable compositions containing these high refractive index polymerizable compounds as inkjet inks. For example, low viscosity polymerizable compositions of 30 mPa·s or less are required as inkjet inks, and polymerizable compounds that have a high refractive index, high polymerizability, and low viscosity are expected.

Polymerizable compounds having a vinyl sulfide group are also known. Patent Document 13 discloses a compound having a polymerizable functional group and a diaryl sulfide skeleton as a composition for nanoimprinting, and discloses vinyl groups, allyl groups, methacryloyl groups, and acryloyl groups as the polymerizable functional groups. Patent Documents 14 to 16 disclose polymerizable compositions containing phenyl vinyl sulfide.

Patent Documents 17 and 18 describe the use of an organic peracid and/or an azo compound to radically polymerize a plastic lens material such as 2-vinylthiobenzothiazole and a radical polymerizable compound such as divinylbenzene under heating. Patent Document 19 describes the use of an organic peracid and/or an azo compound to radically polymerize a polymerizable compound having an aromatic heterocycle, including 2-vinylthiobenzothiazole, under heating as an organic electroluminescence material. Both of these methods use a thermal radical polymerization initiator, and have different compositions from those of the present invention.

JP 2023-38116 A JP 2012-72316 A JP 2019-14767 A JP 2020-37693 A Japanese Patent Application Publication No. 9-25321 JP 2017-190326 A JP 2021-31669 A JP 2018-104696 A JP 2012-82145 A JP 2023-32499 A JP 2017-14213 A JP 2005-133071 A JP 2022-170092 A JP 2022-128911 A International Publication No. 2018/062196 JP 2021-55051 A Japanese Patent Application Publication No. 2-265907 Japanese Patent Application Publication No. 4-225007 JP 2000-87027 A

The object of the present invention is to provide a radical polymerizable composition that is used as a transparent resin raw material suitable for optical applications, and that not only has excellent curing properties, but also has a low viscosity and a high refractive index, and allows adjustment of the refractive index of the polymer obtained by curing.

As a result of intensive research, the inventors discovered that a radically polymerizable composition containing a vinyl sulfide compound having a specific structure and an aryl sulfide compound having a specific structure as resin raw materials has a low viscosity and a very high refractive index, and can be easily polymerized under practical conditions to give a polymer with a high refractive index, leading to the completion of the present invention.

A first invention resides in a radically polymerizable composition comprising (A) a vinyl sulfide compound having a heterocycle represented by general formula (1), (B) an aryl sulfide compound represented by general formula (5), and (C) a radical polymerization initiator, wherein the radically polymerizable composition has a refractive index (n _D ) of 1.60 or more at 25° C.

 

 

In general formula (1), A represents an oxygen atom or a sulfur atom, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or an arylthio group having 6 to 10 carbon atoms, and R ¹ and R ² may bond to each other to form a saturated or unsaturated ring.

 

 

In the general formula (5), ^R3 represents a (meth)acrylic group or a vinyl group, n represents 0 or an integer of 1 to 5. Multiple m's may be the same or different and represent 0 or an integer of 1 to 4, ^R4 represents an alkyl group having 1 to 3 carbon atoms and may be the same or different when there are multiple R4's, and multiple A's may be the same or different and represent an oxygen atom or a sulfur atom.

The second invention is the radical polymerizable composition according to the first invention, characterized in that the content of (A) the vinyl sulfide compound having a heterocycle represented by general formula (1) is 40% by weight or more relative to 100% by weight of the total amount of the radical polymerizable composition.

The third invention is the radical polymerizable composition according to the first invention, characterized in that the viscosity of the radical polymerizable composition at 25°C is 30 mPa·s or less.

The fourth invention is the radical polymerizable composition according to the first invention, characterized in that the radical polymerization initiator (C) is a photoradical polymerization initiator.

The fifth invention is a polymerization method in which the radical polymerizable composition according to any one of the first to fourth inventions is irradiated with active energy rays.

The sixth invention is the polymerization method described in the fifth invention, characterized in that the irradiated active energy rays have a peak wavelength in the wavelength range of 350 nm to 420 nm.

A seventh invention relates to a polymer obtained by polymerizing the radically polymerizable composition according to any one of the first to fourth inventions, characterized in that the polymer has a refractive index ( _nD ) of 1.60 or more at 25°C.

In the present invention, (meth)acrylate means acrylate or methacrylate, (meth)acryloyl means acryloyl or methacryloyl, and (meth)acrylic means acrylic or methacrylic. In addition, the refractive index in the present invention means the refractive index ( _nD ) for the D line (589 nm) at 25°C unless otherwise specified. Furthermore, in the present invention, the viscosity means a value measured at 25°C using an E-type viscometer unless otherwise specified.

The radically polymerizable composition of the present invention has a low viscosity and a high refractive index, and is easily polymerized under practical conditions. By polymerizing the radically polymerizable composition of the present invention, a polymer with an ultra-high refractive index can be obtained.

The objects, features and advantages of the present invention will become more apparent from the detailed description below.

A graph showing the relationship between the ratio of 2-vinylthiobenzoxazole added in a copolymer composition of 2-vinylthiobenzoxazole and 4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) and the refractive index and viscosity of the composition. The smooth line smoothly connects each of the plotted points.

The present invention is described in detail below.

((A) Vinyl sulfide compound having a heterocycle represented by general formula (1))
The vinyl sulfide compound having a heterocycle of the present invention is represented by general formula (1).

 

 

In general formula (1), A represents an oxygen atom or a sulfur atom, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or an arylthio group having 6 to 10 carbon atoms, and R ¹ and R ² may bond to each other to form a saturated or unsaturated ring.

In general formula (1), the alkyl group having 1 to 6 carbon atoms represented by R ¹ and R ² may be a linear alkyl group or a branched alkyl group, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a 2-methylbutyl group, a neopentyl group, a 1-ethylpropyl group, an n-hexyl group, a 4-methylpentyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 1-methylpentyl group, a 3,3-dimethylbutyl group, a 2,2-dimethylbutyl group, a 1,1-dimethylbutyl group, and a 1,2-dimethylbutyl group.

Examples of aryl groups having 6 to 10 carbon atoms include phenyl, tolyl, and naphthyl groups, which may have a substituent. Examples of alkoxy groups having 1 to 6 carbon atoms include linear, branched, or cyclic alkoxy groups, such as methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, and cyclohexyloxy groups. Examples of aryloxy groups having 6 to 10 carbon atoms include phenyloxy, tolyloxy, and naphthyloxy groups, which may have a substituent. Examples of alkylthio groups having 1 to 6 carbon atoms include methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, i-butylthio, n-amylthio, i-amylthio, n-hexylthio, and cyclohexylthio groups. Examples of arylthio groups having 6 to 10 carbon atoms include phenylthio and naphthylthio groups.

In general formula (1), when A is an oxygen atom, the vinyl sulfide compound has a benzoxazole group, and when A is a sulfur atom, the vinyl sulfide compound has a benzothiazole group.

Specific examples of vinyl sulfide compounds having a benzoxazole group in which A in general formula (1) is an oxygen atom include 2-vinylthiobenzoxazole, 2-vinylthio-5-methylbenzoxazole, 2-vinylthio-6-methylbenzoxazole, 2-vinylthio-4-methylbenzoxazole, 2-vinylthio-5,6-dimethylbenzoxazole, 2-vinylthio-naphtho[2,1-d]benzoxazole, 2-vinylthio-naphtho[1,2-d]benzoxazole, 2-vinylthio-5-phenylbenzoxazole, 2-vinyl Examples include thio-5-tert-butylbenzoxazole, 2-vinylthio-4-methoxybenzoxazole, 2-vinylthio-5-methoxybenzoxazole, 2-vinylthio-6-methoxybenzoxazole, 2-vinylthio-6-ethoxybenzoxazole, 2-vinylthio-4-methylthiobenzoxazole, 2-vinylthio-5-methylthiobenzoxazole, 2-vinylthio-6-methylthiobenzoxazole, 2-vinylthio-6-ethylthiobenzoxazole, and 2-vinylthio-6-phenylthiobenzoxazole.

Specific examples of vinyl sulfide compounds having a benzothiazole group in which A in general formula (1) is a sulfur atom include 2-vinylthiobenzothiazole, 2-vinylthio-5-methylbenzothiazole, 2-vinylthio-6-methylbenzothiazole, 2-vinylthio-4-methylbenzothiazole, 2-vinylthio-5,6-dimethylbenzothiazole, 2-vinylthio-naphtho[2,1-d]benzothiazole, 2-vinylthio-naphtho[1,2-d]benzothiazole, 2-vinylthio-5-phenylbenzothiazole, 2-vinyl Examples include 2-vinylthio-5-tert-butylbenzothiazole, 2-vinylthio-4-methoxybenzothiazole, 2-vinylthio-5-methoxybenzothiazole, 2-vinylthio-6-methoxybenzothiazole, 2-vinylthio-6-ethoxybenzothiazole, 2-vinylthio-4-methylthiobenzothiazole, 2-vinylthio-5-methylthiobenzothiazole, 2-vinylthio-6-methylthiobenzothiazole, 2-vinylthio-6-ethylthiobenzothiazole, and 2-vinylthio-6-phenylthiobenzothiazole.

Among the compounds given above as examples, 2-vinylthiobenzoxazole of the following structural formula (2) and 2-vinylthiobenzothiazole of the structural formula (3) are preferred in terms of ease of synthesis, refractive index, and viscosity. In addition, compounds in which A in general formula (1) is an oxygen atom are preferred in terms of polymerization at low exposure doses and the resulting polymer has high transmittance and low yellowness, and 2-vinylthiobenzoxazole of structural formula (2) is particularly preferred in terms of ease of synthesis.

 

 

 

 

(Synthesis Method)
The compound of general formula (1) can be synthesized by a known method. For example, as shown in the following reaction formula 1, a 2-mercaptobenzoxazole compound or a 2-mercaptobenzothiazole compound is reacted with a dihalogenated ethane such as 1,2-dibromoethane in the presence of a base, and then the resulting mixture is dehydrohalogenated in the presence of a base, thereby synthesizing the compound of general formula (1).

 

 

In reaction formula 1, A represents an oxygen atom or a sulfur atom, ^R1 and ^R2 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or an arylthio group having 6 to 10 carbon atoms, and ^R1 and ^R2 may be bonded to each other to form a saturated or unsaturated ring. X represents a chlorine atom or a bromine atom, and the two Xs may be the same or different.

Normally, the reaction of the compound of general formula (4) with dihalogenated ethane causes a substitution reaction of the thiol group to produce a thioether compound, but almost simultaneously, the hydrogen halide is eliminated to produce a double bond, and the desired vinyl sulfide compound having a heterocycle of general formula (1) can be obtained without isolating the intermediate.

The vinyl sulfide having a heterocycle represented by general formula (1) synthesized by the above method is a compound with extremely low viscosity and high refractive index. For example, 2-vinylthiobenzoxazole, which is a vinyl sulfide having a heterocycle of the present invention, is a liquid compound, has an extremely low viscosity of 4.2 mPa·s at 25°C, and exhibits a high refractive index of 1.62. 2-vinylthiobenzothiazole is also a liquid compound, has an extremely low viscosity of 7.6 mPa·s at 25°C, and exhibits a very high refractive index of 1.68.

In addition, the vinyl sulfide having a heterocycle represented by the general formula (1) of the present invention can be polymerized and cured using a commercially available photoradical polymerization initiator, and is an extremely useful polymerizable compound that can be polymerized and cured not only with light sources such as high-pressure mercury lamps, but also with light sources with a single wavelength and weak irradiation energy such as ultraviolet LEDs and semiconductor lasers. It also has extremely high compatibility with other polymerizable compounds such as (meth)acrylic acid esters, and the radical polymerizable composition obtained by mixing it can also maintain a low viscosity, and the obtained polymerized and cured product exhibits a high refractive index. In terms of a high refractive index, 2-vinylthiobenzothiazole compounds are preferred. In addition, 2-vinylthiobenzoxazole compounds are particularly preferred because they are polymerized with a low amount of exposure, and the polymerized product exhibits an ultra-high refractive index, high transmittance, and low YI (yellowing index).

((B) Aryl sulfide compound represented by general formula (5))
The aryl sulfide compound of the present invention is represented by the general formula (5).

 

 

In the general formula (5), ^R3 represents a (meth)acrylic group or a vinyl group, n represents 0 or an integer of 1 to 5. Multiple m's may be the same or different and represent 0 or an integer of 1 to 4, ^R4 represents an alkyl group having 1 to 3 carbon atoms and may be the same or different when there are multiple R4's, and multiple A's may be the same or different and represent an oxygen atom or a sulfur atom.

Specific examples of aryl sulfides represented by general formula (5) include 4,4'-bis(methacryloylthio)diphenyl sulfide, 4,4'-bis(acryloylthio)diphenyl sulfide, 4,4'-bis(methacryloyloxymethylthio)diphenyl sulfide, 4,4'-bis(acryloyloxymethylthio)diphenyl sulfide, 4,4'-bis(methacryloyloxyethylthio)diphenyl sulfide, 4,4'-bis(acryloyloxyethylthio)diphenyl sulfide, 4,4'-bis(methacryloyloxybutylthio)diphenyl sulfide, 4,4'-bis(acryloyloxybutylthio)diphenyl sulfide, and 4,4'-bis(vinylthio)diphenyl sulfide. , 4,4'-bis(allylthio)diphenyl sulfide, 4,4'-bis(methacryloylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxymethylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxymethylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxyethylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxyethylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxybutylthio)-3,3' -dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxybutylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(vinylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(allylthio)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloylthio)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloylthio)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxymethylthio)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxymethylthio)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloyloxymethylthio)-3,3',5,5'-tetramethyl-diphenyl sulfide Examples include methyl diphenyl sulfide, 4,4'-bis (methacryloyloxyethylthio)-3,3',5,5'-tetramethyl diphenyl sulfide, 4,4'-bis (acryloyloxyethylthio)-3,3',5,5'-tetramethyl diphenyl sulfide, 4,4'-bis (methacryloyloxybutylthio)-3,3',5,5'-tetramethyl diphenyl sulfide, 4,4'-bis (acryloyloxybutylthio)-3,3',5,5'-tetramethyl diphenyl sulfide, 4,4'-bis (vinylthio)-3,3',5,5'-tetramethyl diphenyl sulfide, and 4,4'-bis (allylthio)-3,3',5,5'-tetramethyl diphenyl sulfide.

In addition, 4,4'-bis(methacryloyloxy)diphenyl sulfide, 4,4'-bis(acryloyloxy)diphenyl sulfide, 4,4'-bis(methacryloyloxymethoxy)diphenyl sulfide, 4,4'-bis(acryloyloxymethoxy)diphenyl sulfide, 4,4'-bis(methacryloyloxyethoxy)diphenyl sulfide, 4,4'-bis(acryloyloxyethoxy)diphenyl sulfide, 4,4'-bis(methacryloyloxybutoxy)diphenyl sulfide, 4,4'-bis(acryloyloxybutoxy)diphenyl sulfide, 4,4'-bis(vinyloxy)diphenyl sulfide, 4,4'-bis(allyloxy)diphenyl sulfide 4,4'-bis(methacryloyloxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxymethoxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxymethoxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxyethoxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(acryloyloxyethoxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxybutoxy)-3,3'-dimethyl-diphenyl sulfide 4,4'-bis(acryloyloxybutoxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(vinyloxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(allyloxy)-3,3'-dimethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloyloxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxymethoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloyloxymethoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide phenyl sulfide, 4,4'-bis(methacryloyloxyethoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloyloxyethoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(methacryloyloxybutoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(acryloyloxybutoxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(vinyloxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, 4,4'-bis(allyloxy)-3,3',5,5'-tetramethyl-diphenyl sulfide, etc.

Among these, 4,4'-bis(methacryloylthio)diphenyl sulfide, 4,4'-bis(acryloyloxyethylthio)diphenyl sulfide, 4,4'-bis(vinylthio)diphenyl sulfide, 4,4'-bis(acryloyloxy)diphenyl sulfide, and 4,4'-bis(methacryloyloxy)diphenyl sulfide are preferred, and 4,4'-bis(methacryloylthio)diphenyl sulfide in which ^R3 is a methacryl group, n and m are 0, and A is a sulfur atom is particularly preferred.

The aryl sulfide compound represented by the general formula (5) is generally a viscous liquid or solid, depending on its structure, and is used in a solvent or mixed with a low-viscosity polymerizable compound for polymerization. For example, 4,4'-bis(methacryloylthio)diphenyl sulfide is available as a reagent, but is a white crystal with a melting point of 64°C. In addition, 4,4'-bis(acryloyloxyethylthio)diphenyl sulfide has a relatively low viscosity, but Table 1-1 of JP 2011-170073 A describes that the viscosity of the composition at 23°C is 150 mPa·s.

As mentioned above, aryl sulfide compounds themselves have a high refractive index, but many of them are solids or high-viscosity liquids, and when polymerizing them, it is undesirable to use a solvent due to issues such as outgassing. Also, when copolymerizing with a low-viscosity polymerizable compound, the low-viscosity polymerizable compound often has a low refractive index, making it difficult to obtain a copolymer with a high refractive index.

The vinyl sulfide compound having a heterocycle represented by the general formula (1) of the present invention is highly compatible with the aryl sulfide compound represented by the general formula (5), and not only has a high refractive index but also a very low viscosity, so that by adding it to the aryl sulfide compound, the viscosity of the copolymer composition can be rapidly reduced, and the refractive index of the copolymer becomes extremely high. As can be seen from Figure 1, by specifying the composition of the composition of the present invention, it is possible to obtain a radical polymerizable composition with a high refractive index and low viscosity, for example, a refractive index of 1.60 or more and a viscosity of the composition at 25°C of 20 mPa·s or less.

In the radical polymerizable composition of the present invention, the addition ratio of the vinyl sulfide compound (A) represented by general formula (1) is preferably 1% by weight or more, more preferably 10% by weight or more, relative to 100% by weight of the total amount of the radical polymerizable composition, and particularly preferably 40% by weight or more in terms of the viscosity of the copolymer composition.

In the radical polymerizable composition of the present invention, compositions having various refractive indices and viscosities can be prepared by adjusting the composition ratio of (A) the vinyl sulfide compound having a heterocycle represented by general formula (1) and (B) the aryl sulfide compound represented by general formula (5). A preferred composition ratio is selected to obtain a desired refractive index and viscosity. For example, in an example in which 2-vinylthiobenzoxazole is used as the vinyl sulfide compound having a heterocycle represented by general formula (1) (A) and 4,4'-bis(methacryloylthio)diphenyl sulfide is used as the aryl sulfide compound represented by general formula (B) (B), it can be seen from FIG. 1 that a copolymerizable composition having a viscosity of 30 mPa·s or less at 25°C can be prepared by setting the amount of 2-vinylthiobenzoxazole to 42% by weight or more. The refractive index (n _D ) of the composition at 25°C at this time is about 1.65.

The aryl sulfide compound of the present invention can be synthesized from commercially available 4,4'-thiobisbenzenethiol or 4,4'-thiodiphenol by a known method.

Radically polymerizable compounds other than (A) and (B) can be used in the radically polymerizable composition of the present invention, as long as the effects of the present invention are not impaired. Examples of such compounds include vinyl ethers, vinyl sulfides other than those of general formula (1), (meth)acrylic acid, (meth)acrylonitrile, monofunctional (meth)acrylates, monofunctional (meth)acrylamides, polyfunctional (meth)acrylates, polyfunctional (meth)acrylamides, and oligomers thereof.

Of these, monofunctional (meth)acrylates and polyfunctional (meth)acrylates are preferred. Examples of monofunctional (meth)acrylates that can be used include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxyethyl acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, tridecyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, phenoxyethyl (meth)acrylate, methyl acrylate, ethyl ... Examples of the acrylates include ethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl acrylate, 2-methyl-2-adamantyl (meth)acrylate, allyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyhexyl (meth)acrylate.

Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ditetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,7-heptanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate Examples of monomers and oligomers include bisphenol A di(meth)acrylate, ethylene oxide modified phosphate di(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene oxide modified bisphenol A di(meth)acrylate, propylene oxide modified bisphenol A di(meth)acrylate, cyclohexane dimethanol di(meth)acrylate, acrylate ester (dioxane glycol diacrylate), alkoxylated hexanediol di(meth)acrylate, alkoxylated cyclohexane dimethanol di(meth)acrylate, epoxy (meth)acrylate, and urethane (meth)acrylate. From the viewpoint of commercial availability, examples of polyfunctional (meth)acrylates include, for example, trade names CN2203 and CN2270 manufactured by SARTOMER, and trade names M-6100 and M-8060 manufactured by Toa Gosei Co., Ltd.; examples of urethane acrylates include, for example, trade names UV-3200B, UV-3000B, UV-6640B, UV-3700B, UV-3310B, and UV-7000B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.; trade names U-4HA and U-200PA manufactured by Shin-Nakamura Chemical Co., Ltd.; and trade names EBECRYL245, EBECRYL1259, and EBECRYL260 manufactured by Daicel-Cytec Co., Ltd. Examples of the epoxy (meth)acrylate that can be used include ECRYL8210, EBECRYL284, EBECRYL8402, CN944, CN969, CN9002, and CN9029 manufactured by SARTOMER Co., Ltd., UN1255 and UN-5507 manufactured by Negami Chemical Industry Co., Ltd., and AH-600 and UA-306I manufactured by Kyoeisha Chemical Co., Ltd., and EBECRYL1259, EBECRYL605, and EBECRYL1606 manufactured by Daicel-Cytec Co., Ltd., and CN110, CN120, and CN153 manufactured by SARTOMER Co., Ltd. Furthermore, from the viewpoint of the viscosity of the resin composition, ease of handling, and the like, urethane acrylate UV-6640B or U-200PA is more preferable. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

((C) Radical Polymerization Initiator)
A radical polymerization initiator is added to the radical polymerizable composition of the present invention. The radical polymerization initiator is not particularly limited, but from the viewpoint of ease of production of the cured product, resolution, and pattern formability, polymerization curing by light irradiation is preferred, and in that sense, a photoradical polymerization initiator is preferred. The photoradical polymerization initiator refers to a compound that generates radicals when irradiated with light, that is, a compound that absorbs light energy, decomposes and/or reacts, and generates radicals. A compound that generates radicals by heat, that is, a compound that absorbs heat energy, decomposes, and generates radical species, for example, a peroxide-based radical polymerization initiator or an azo-based radical polymerization initiator, is not included in the photoradical polymerization initiator of the present invention. The photoradical polymerization initiator can be any commonly used one without any particular limitation, and for example, one or more photoradical polymerization initiators selected from the group consisting of alkylphenone-based photoradical polymerization initiators, benzophenone-based photoradical polymerization initiators, acylphosphine oxide-based photoradical polymerization initiators, oxime ester-based photoradical polymerization initiators, α-aminoacetophenone-based photoradical polymerization initiators, biimidazole-based photoradical polymerization initiators, triazine-based photoradical polymerization initiators, and thioxanthone-based photoradical polymerization initiators can be used.

Examples of alkylphenone-based photoradical polymerization initiators include 2,2'-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan Examples include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzylmethyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-1-butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, and N,N-dimethylaminoacetophenone.

Examples of benzophenone-based photoradical polymerization initiators include benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone.

Examples of acylphosphine oxide-based photoradical polymerization initiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name "Omnirad TPO" manufactured by IGM Group B.V.) and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (trade name "Omnirad 819" manufactured by IGM Group B.V.).

Examples of oxime ester photoradical polymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime) (product name "IrgacureOXE01" manufactured by BASF, Irgacure is a registered trademark of BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetone), ethyl oxime) (trade name "Irgacure OXE02" manufactured by BASF), [8-[[(acetyloxy)imino][2-(2,2,3,3-tetrafluoropropoxy)phenyl]methyl]-11-(2-ethylhexyl)-11H-benzo[a]carbazol-5-yl]-,(2,4,6-trimethylphenyl) (trade name "Irgacure OXE03" manufactured by BASF), etc.

Examples of α-aminoacetophenone-based photoradical polymerization initiators include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (trade name "Omnirad 907" manufactured by IGM Group B.V.), 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (trade name "Omnirad 369" manufactured by IGM Group B.V.), and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholino-4-yl-phenyl)butan-1-one (trade name "Omnirad 379" manufactured by IGM Group B.V.).

Examples of biimidazole-based photoradical polymerization initiators include 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer.

Examples of triazine-based photoradical polymerization initiators include 2-(3,4-methylenedioxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, etc.

Examples of thioxanthone-based photoradical polymerization initiators include 2,4-diethylthioxanthone and 2-isopropylthioxanthone.

The alkylphenone-based photoradical polymerization initiator, benzophenone-based photoradical polymerization initiator, acylphosphine oxide-based photoradical polymerization initiator, oxime ester-based photoradical polymerization initiator, α-aminoacetophenone-based photoradical polymerization initiator, biimidazole-based photoradical polymerization initiator, triazine-based photoradical polymerization initiator, and thioxanthone-based photoradical polymerization initiator that can be used in the present invention can each be used alone, or multiple types can be used in combination depending on the application, etc.

Among the photoradical polymerization initiators listed above, biimidazole-based photoradical polymerization initiators, alkylphenone-based photoradical polymerization initiators, acylphosphine oxide-based photoradical polymerization initiators, and oxime-based photoradical polymerization initiators are preferred. In terms of activity, acylphosphine oxide-based photoradical polymerization initiators and oxime ester-based photoradical polymerization initiators are particularly preferred.

The amount of photoradical polymerization initiator added is preferably 0.1% by weight or more and 10% by weight or less relative to the radical polymerizable composition.

(Photoradical polymerization sensitizer)
Conventionally, high pressure mercury lamps have been used as light sources in photoradical polymerization, but due to problems such as high energy consumption, curing devices using LED light sources, which have low running costs and little impact on the natural environment, have come to be used. However, these LED light sources emit light with long wavelengths such as 365 nm, 385 nm, 395 nm, and 405 nm, and unlike high pressure mercury lamps, they emit light of a single wavelength, so there is a problem that the irradiation energy is weak. With such LED lamps, it is often the case that conventional photoradical polymerization initiators cannot sufficiently cure. In order to deal with such long wavelength, single light LED lamps, it is preferable to further add a photoradical polymerization sensitizer. By adding a photoradical polymerization sensitizer that absorbs long wavelength light, the radical generation reaction of the photoradical polymerization initiator can be promoted, and the reactivity of the radical polymerization can be improved.

As the photoradical polymerization sensitizer, any commonly used sensitizer that is active to light of the irradiation wavelength can be used without any particular restrictions. For example, thioxanthone-based sensitizers such as isopropylthioxanthone and diethylthioxanthone, benzophenone-based sensitizers such as 4,4'-bis(diethylamino)benzophenone, anthracene-based sensitizers such as 9,10-diethoxyanthracene, 9,10-dibutoxyanthracene, 9,10-bisheptanoyloxyanthracene, and 9,10-bisoctanoyloxyanthracene, coumarin-based sensitizers such as coumarin and ketocoumarin, acridine orange, camphorquinone, etc. can be used.

The amount of the photoradical polymerization sensitizer added is preferably 0.1% by weight or more and 10% by weight or less relative to the radical polymerizable composition.

The radically polymerizable composition of the present invention may contain a polymerization accelerator depending on the photoradical polymerization initiator used. Examples of the polymerization accelerator include amine compounds such as ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, methyl p-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, and butoxyethyl p-dimethylaminobenzoate.

The radical polymerizable composition of the present invention may also contain a polymerization inhibitor to enhance the stability of the composition. Examples of polymerization inhibitors include at least one compound selected from the group consisting of hydroquinone, hydroquinone monomethyl ether, 1,4-benzoquinone, tert-butylhydroquinone, and 4-tert-butylpyrocatechol.

Furthermore, the radical polymerizable composition of the present invention may contain a surfactant, and the surfactant is preferably a nonionic surfactant.  By containing a nonionic surfactant, the coating properties when the radical polymerizable composition is applied to a substrate to obtain a resin film are improved, and a coating film of uniform thickness can be obtained. The nonionic surfactant is, for example, a compound containing a fluorine group (e.g., a fluorinated alkyl group) or a silanol group, or a compound having a siloxane bond as the main skeleton. It is preferable to use one containing a fluorine-based surfactant or a silicone-based surfactant. Examples of fluorine-based surfactants include, but are not limited to, Megafac F-171, F-173, F-444, F-470, F-471, F-475, F-482, F-477, F-554, F-556, and F-557 manufactured by DIC Corporation, and Novec FC4430 and FC4432 manufactured by Sumitomo 3M Limited. Silicone-based surfactants include surfactants having siloxane bonds in the molecule. Specific examples of the surfactant include Toray Silicone DC3PA, SH7PA, DC11PA, SH21PA, SH28PA, SH29PA, SH30PA, and SH8400 (trade name: manufactured by Toray Dow Corning Co., Ltd.), KP321, KP322, KP323, KP324, KP326, KP340, and KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF4446, TSF4452, and TSF4460 (manufactured by Momentive Performance Materials Japan LLC). Examples of the silicone surfactant having a fluorine atom include a surfactant having a siloxane bond and a fluorocarbon chain in the molecule. Specific examples include Megafac (registered trademark) R08, BL20, F475, F477, and F443 (manufactured by DIC Corporation).

In addition to the above, the radical polymerizable composition of the present invention may contain various resin additives such as pigments, dyes, diluents, organic or inorganic fillers, leveling agents, surfactants, dispersants, defoamers, thickeners, flame retardants, surface modifiers, penetration promoters, moisture absorbents, moisturizers, fixing agents, antifungal agents, preservatives, antioxidants, UV absorbers, chelating agents, pH adjusters, stabilizers, lubricants, and plasticizers, within the scope of the present invention.

(Polymerization method)
A cured product can be obtained by irradiating the radical polymerizable composition of the present invention with light and polymerizing it. For example, when the radical polymerizable composition is irradiated with light to polymerize and photocure it, the radical polymerizable composition can be molded into a film and photocure it, or it can be molded into a block and photocure it. When the composition is molded into a film and photocure it, the liquid radical polymerizable composition is applied to a substrate such as a polyester film using a bar coater or the like so as to have a film thickness of 5 to 300 microns. On the other hand, the composition can be applied to a thinner or thicker film thickness by spin coating or screen printing. The vinyl sulfide compound having a heterocycle represented by the general formula (1) of the present invention and the copolymerizable composition thereof have a low viscosity, so that they may be used as ink for inkjet printing.

A cured product can be obtained by irradiating a coating film or droplets of the radically polymerizable composition thus prepared with energy rays (ultraviolet rays) having a wavelength range of 300 nm to 500 nm at an intensity of about 1 to 1000 mW/cm ^2. Examples of light sources that can be used include high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, gallium-doped lamps, black lights, 405 nm ultraviolet LEDs, 395 nm ultraviolet LEDs, 385 nm ultraviolet LEDs, 365 nm ultraviolet LEDs, semiconductor lasers, blue LEDs, white LEDs, D bulbs and V bulbs manufactured by Fusion, Inc. In particular, it is characterized by being cured even with light of a single wavelength including a long wavelength range of 365 nm to 405 nm, such as a 405 nm ultraviolet LED, a 395 nm ultraviolet LED, a 385 nm ultraviolet LED, a 375 nm ultraviolet LED, or a 365 nm ultraviolet LED, and ultraviolet LEDs or semiconductor lasers with central wavelengths of 365 nm, 375 nm, 385 nm, 395 nm, or 405 nm are particularly preferred as the irradiation source.

The following examples further illustrate specific aspects of the present invention, but the present invention is not limited to these examples as long as the gist of the invention is not exceeded. In other words, the following examples are not intended to be exhaustive or to limit the present invention to the exact form described. Therefore, the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. Furthermore, all parts and percentages are by weight unless otherwise specified.

(Identification of Compounds)
The identity of the obtained compound was determined using the following instruments.
(1) ^1H -NMR analysis: Nuclear magnetic resonance apparatus (NMR), manufactured by JEOL Ltd., model: JNM ECS 400 type FT NMR Spectrometer)
(2) Mass spectrum: Measurement was performed using a mass spectrometer, model GCMS-QP2000, manufactured by Shimadzu Corporation.

(Measurement of physical properties of compounds)
Measurement of physical properties of the obtained compound (1) Viscosity: E-type viscometer (Toki Sangyo, TVE-35H)
(2) Refractive index: Refractometer (measurement conditions: 25° C., n _D )
In the case of liquid (1.50≦n _D ≦1.70)
Model name: ERMA, ER-7MW-H
For liquids/films/thin films (1.30≦n _D ≦1.70)
Model name: Anton Paar Japan, AbbematMw
For thin films (n _D >1.70)
Model name: Atago, DR-M4
(3) Transmittance: SHIMADZU, UV-2600

(Viscosity measurement of compounds)
The viscosity was measured using an E-type viscometer TVE35H. A cone rotor of 1°34'×R24 was used, and after adjusting the gap between the sample cup and the cone rotor, 1.1 mL of sample was injected into the center of the sample cup using a syringe. The sample cup was then set in the viscometer body, and the cone rotor was rotated at 25° C. and 20 rpm. The value at which the viscosity became constant was taken as the viscosity value.

(Refractive index measurement method)
In the case of a liquid (1.50≦n _D ≦1.70), the measurement was performed at 25° C. using a refractometer ER-7MW-H manufactured by ERMA.
In the case of a liquid/film/thin film (1.30≦n _D ≦1.70), the measurement was performed at 25° C. using AbbematMw manufactured by Anton Paar Japan.
In the case of a thin film (n _D >1.70), the measurement was performed at 25° C. using Atago's DR-M4.

(Method of measuring transmittance)
The transmittance at 430 nm of the thin film obtained on the glass substrate was measured using a UV-VIS SPECTROPHOTOMETER (Shimazu Corporation, "UV-2600").

(Method of measuring YI value)
As with the transmittance, the YI value was calculated using a UV-VIS SPECTROPHOTOMETER (Shimazu Corporation, "UV-2600") and color measurement software.

(tack free test)
As a method for determining whether the radical polymerizable composition of the present invention has been photocured, there is a tack-free test (finger touch test). That is, when the radical polymerizable composition is irradiated with light, it is cured and the tack (stickiness) of the surface disappears, so whether it has been cured or not is confirmed by whether the tack (stickiness) has disappeared after the light irradiation.

(UV exposure machine)
Model name: MATSUO, UV-LED CURE M/C, JVC-200-SC-N-POWER

[Synthesis Example 1]
2-mercaptobenzoxazole (50.00 g, 0.331 mol), 1,2-dibromoethane (124.25 g, 0.661 mol), and 4-methyltetrahydropyran (500 g) were placed in a three-necked flask, stirred and mixed at room temperature, and then heated to 70°C. Then, DBU (diazabicycloundecene, 100.69 g, 0.661 mol) was added dropwise, and the mixture was stirred for 3 hours after the addition was completed. Then, the reaction solution was cooled to room temperature, and the precipitated salt and by-products were removed by vacuum filtration, the organic layer was washed with pure water, dehydrated and filtered with anhydrous magnesium sulfate, and the solvent was distilled off with an evaporator. Then, vacuum distillation was performed to obtain the target product, 2-vinylthiobenzoxazole, as a colorless transparent liquid, with a yield of 17.1 g and a yield of 29%. _{n D} = 1.62, viscosity (25°C): about 4.2 mPa·s. The refractive index and viscosity are shown in Table 3.

[Synthesis Example 2]
2-mercaptobenzothiazole (37.29 g, 0.223 mol), 1,2-dibromoethane (83.77 g, 0.446 mol), and 4-methyltetrahydropyran (186.4 g) were placed in a three-necked flask, stirred and mixed at room temperature, and then heated to 70°C. Then, DBU (diazabicycloundecene, 67.89 g, 0.446 mol) was added dropwise, and the mixture was stirred for 3 hours after the dropwise addition was completed. Then, the reaction solution was cooled to room temperature, and the precipitated salt and by-products were removed by vacuum filtration, the organic layer was washed with pure water, dehydrated and filtered with anhydrous magnesium sulfate, and the solvent was distilled off with an evaporator. Then, vacuum distillation was performed to obtain the target product, 2-vinylthiobenzothiazole, as a pale yellow transparent liquid, with a yield of 9.1 g and a yield of 24%. _{n D} = 1.69, viscosity (25°C): about 7.6 mPa·s. The refractive index and viscosity are shown in Table 3.

[Example 1] Photoradical polymerization of 2-vinylthiobenzoxazole 1
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 365 nm at an illuminance of 100 mW and an exposure amount of 30 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index after curing (n _D ) was 1.67, the visible light transmittance was 92%, and the YI value was 3.1. The results are shown in Tables 1 and 2.

[Example 2] Photoradical polymerization of 2-vinylthiobenzoxazole 2
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 365 nm at an illuminance of 100 mW and an exposure amount of 3 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index after curing (n _D ) was 1.67, the visible light transmittance was 92%, and the YI value was 3.5. The results are shown in Table 1.

[Example 3] Photoradical polymerization of 2-vinylthiobenzoxazole 3
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 365 nm at an illuminance of 100 mW and an exposure amount of 0.3 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index (n _D ) after curing was 1.69, the visible light transmittance was 94%, and the YI value was 2.1. The results are shown in Table 1.

[Example 4] Photoradical polymerization of 2-vinylthiobenzoxazole 4
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 405 nm at an illuminance of 100 mW and an exposure amount of 30 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index after curing (n _D ) was 1.67, the visible light transmittance was 94%, and the YI value was 1.9. The results are shown in Table 1.

[Example 5] Photoradical polymerization of 2-vinylthiobenzoxazole 5
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 405 nm at an illuminance of 100 mW and an exposure amount of 3 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index (n _D ) after curing was 1.67, the visible light transmittance was 95%, and the YI value was 1.8. The results are shown in Table 1.

[Example 6] Photoradical polymerization of 2-vinylthiobenzoxazole 6
To 100 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and the mixture was dissolved by applying ultrasonic waves. This radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 405 nm at an illuminance of 100 mW and an exposure amount of 0.3 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.62, the refractive index (n _D ) after curing was 1.68, the visible light transmittance was 95%, and the YI value was 0.3. The results are shown in Table 1.

[Example 7] Photoradical polymerization synthesis of 2-vinylthiobenzothiazole To 100 parts of 2-vinylthiobenzothiazole obtained by the same method as in Example 2, 3 parts of OmniradTPO as a photoradical polymerization initiator and 1 part of fluorosurfactant Megafac F-477 (Megafac is a registered trademark of DIC Corporation) were added, and dissolved by applying ultrasonic waves. This photoradical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 365 nm at an illuminance of 100 mW and an exposure amount of 30 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.68, the refractive index (n _D ) after curing was 1.71, the visible light transmittance was 70%, and the YI value was 15.5. The results are shown in Table 1.

 

 

As is clear from Synthesis Examples 1 and 2 and Examples 1 to 7 and Table 1, the compounds of the present invention, 2-vinylthiobenzoxazole and 2-vinylthiobenzothiazole, have an extremely low viscosity of 10 mPa·s or less at 25° C., can be easily polymerized even with light of a single long wavelength such as 365 nm or 405 nm, and have an ultrahigh refractive index (n _D ) of 1.67 to 1.71. Furthermore, it can be seen that a polymer obtained by curing 2-vinylthiobenzoxazole in which A in general formula (1) is an oxygen atom has a low yellowness with a YI value of 3.5 to 2.1, and in particular, products cured with low exposure or at a long wavelength of 405 nm tend to show a low YI value of 1.9 to 0.3.

[Example 8] Photoradical copolymerization of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide 1
50 parts of 2-vinylthiobenzoxazole obtained by the same method as in Synthesis Example 1 and 50 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were mixed, 3 parts of OmniradTPO and 1 part of Megafac F-477 were added, and the mixture was dissolved by applying ultrasonic waves. 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were easily mixed together to form a uniform liquid phase. Thereafter, the prepared radical polymerizable composition was formed into a film of 10 μm on a glass substrate using a bar coater, and after replacing the inside of the exposure machine with nitrogen, it was cured by irradiating light with a wavelength of 365 nm at 30 J/cm ^2. When the tack of the surface was confirmed after exposure, there was no tack. The liquid refractive index before curing was 1.64, the refractive index after curing (n _D ) was 1.68, the visible light transmittance was 91%, and the YI was 2.4. The 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) used was manufactured by Tokyo Chemical Industry Co., Ltd. This reagent is a white solid, and was dissolved in ethyl benzoate at several concentrations to measure the viscosity at 25°C. The refractive index (n _D ) of BMTPS was calculated to be 1.645 by extrapolation.

[Example 9] Photoradical copolymerization of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide 2
A composition was prepared in the same manner as in Example 7, except that 40 parts of 2-vinylthiobenzoxazole and 60 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were used, and exposure was performed in the same manner to obtain a polymer. When the tackiness of the surface was checked after exposure, there was no tackiness. The liquid refractive index before curing was 1.64, and the refractive index (n _D ) after curing was 1.69, the visible light transmittance was 90%, and the YI was 3.4.

[Example 10] Photoradical copolymerization of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide 3
A composition was prepared and exposed in the same manner as in Example 7, except that 40 parts of 2-vinylthiobenzoxazole, 60 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS), and the wavelength of the irradiated light were 405 nm, to obtain a polymer. When the tackiness of the surface was checked after exposure, no tackiness was found. The liquid refractive index before curing was 1.64, and the refractive index (n _D ) after curing was 1.69, the visible light transmittance was 93%, and the YI was 1.6.

[Example 11] Photoradical copolymerization of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide 4
The curing was carried out in the same manner as in Example 8, except that the exposure dose was 0.3 J/ ^cm2 . When the tackiness of the surface was checked after exposure, there was no tackiness. The liquid refractive index before curing was 1.64, the refractive index after curing ( _nD ) was 1.69, the visible light transmittance was 96%, and the YI was 0.5.

[Example 12] Photoradical copolymerization of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide 5
The curing was carried out in the same manner as in Example 9, except that the exposure dose was 0.3 J/ ^cm2 . When the tackiness of the surface was checked after exposure, there was no tackiness. The liquid refractive index before curing was 1.64, the refractive index after curing ( _nD ) was 1.69, the visible light transmittance was 96%, and the YI was 1.0.

 

 

As is clear from Examples 8 to 12 and Table 2, the copolymer composition of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS), which is the compound of the present invention, can be easily polymerized even with light of a single long wavelength such as 365 nm or 405 nm, and the refractive index (n _D ) of the obtained polymer is an ultra-high refractive index of 1.67 to 1.69. In addition, the polymer obtained by curing the copolymer composition has a low yellowness index with a YI value of 3.5 or less, and in particular, it is found that the product cured with a low exposure dose or at a long wavelength of 405 nm shows a low YI value of 1.0 or less.

[Example 13] Preparation of photoradical copolymerization composition of 2-vinylthiobenzoxazole and aryl sulfide 1
90 parts of 2-vinylthiobenzoxazole obtained in the same manner as in Synthesis Example 2 and 10 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were mixed and dissolved by applying ultrasonic waves. The dissolution rate of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) was extremely fast, and they were easily mixed together to form a uniform liquid phase. The refractive index (n _D ) of the composition was 1.63 and the viscosity was 5.4 mPa·s. The results are shown in Table 3 and Figure 1.

[Example 14] Preparation of photoradical copolymerization composition of 2-vinylthiobenzoxazole and aryl sulfide 2
50 parts of 2-vinylthiobenzoxazole obtained in the same manner as in Synthesis Example 2 and 50 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were mixed and dissolved by applying ultrasonic waves. The dissolution rate of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) was extremely fast, and they were easily mixed together to form a uniform liquid phase. The refractive index (n _D ) of the composition was 1.64 and the viscosity was 20.2 mPa·s. The results are shown in Table 3 and Figure 1.

[Example 15] Preparation of photoradical copolymerization composition of 2-vinylthiobenzoxazole and aryl sulfide 3
40 parts of 2-vinylthiobenzoxazole obtained in the same manner as in Synthesis Example 2 and 60 parts of 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) were mixed and dissolved by applying ultrasonic waves. The dissolution rate of 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) was extremely fast, and they were easily mixed together to form a uniform liquid phase. The refractive index (n _D ) of the composition was 1.64 and the viscosity was 32.5 mPa·s. The results are shown in Table 3 and Figure 1.

 

 

As is clear from Table 3, Synthesis Example 1, and Examples 13 to 15, 2-vinylthiobenzoxazole, a compound of the present invention, is easily dissolved and mixed with 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS), an aryl sulfide, to form a copolymer composition. As is clear from FIG. 1, the refractive index _nD of the composition has an additivity between the composition ratio and the refractive index, and it is understood that the refractive index of the composition can be adjusted. In addition, in terms of viscosity adjustment, the viscosity reducing effect of the amount of 2-vinylthiobenzoxazole, a compound of the present invention, added to a copolymer composition of 2-vinylthiobenzoxazole, a compound of the present invention, and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS) is large, and the viscosity of the copolymer composition can be greatly reduced by adding a small amount. For example, in the case of using 2-vinylthiobenzoxazole and 4,4'-bis(methacryloylthio)diphenyl sulfide (BMTPS), in order to prepare a copolymerizable composition having a viscosity of 20 mPa·s or less at 25°C, it is understood from FIG. 1 that this can be achieved by setting the amount of 2-vinylthiobenzoxazole to 50% by weight or more.

The compound represented by the general formula (1) of the present invention is a radically polymerizable compound used as a transparent resin raw material suitable for optical applications, and is a radically polymerizable compound that not only has excellent curability but also has low viscosity, and the polymer obtained by curing has excellent flexibility and a high refractive index.

Claims (7)

(A) a vinyl sulfide compound having a heterocycle represented by general formula (1),
(B) an aryl sulfide compound represented by general formula (5),
(C) a radical polymerization initiator,
A radically polymerizable composition comprising:
The radical polymerizable composition is characterized in that the refractive index (n _D ) of the radical polymerizable composition at 25° C. is 1.60 or more.

(In general formula (1), A represents an oxygen atom or a sulfur atom, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, or an arylthio group having 6 to 10 carbon atoms, and R ¹ and R ² may be bonded to each other to form a saturated or unsaturated ring.)

(In the general formula (5), ^R3 represents a (meth)acrylic group or a vinyl group, n represents 0 or an integer of 1 to 5, m, which may be the same or different, represents 0 or an integer of 1 to 4, ^R4 represents an alkyl group having 1 to 3 carbon atoms, which may be the same or different when there are multiple R4s, and A, which may be the same or different, represents an oxygen atom or a sulfur atom.) The radical polymerizable composition according to claim 1, characterized in that the content of (A) the vinyl sulfide compound having a heterocycle represented by general formula (1) is 40% by weight or more relative to 100% by weight of the total amount of the radical polymerizable composition. The radical polymerizable composition according to claim 1, characterized in that the viscosity of the radical polymerizable composition at 25°C is 30 mPa·s or less. The radical polymerizable composition according to claim 1, characterized in that the radical polymerization initiator (C) is a photoradical polymerization initiator. A polymerization method comprising irradiating the radically polymerizable composition according to any one of claims 1 to 4 with active energy rays. The polymerization method according to claim 5, characterized in that the active energy rays irradiated have a peak wavelength in the wavelength range of 350 nm to 420 nm. A polymer obtained by polymerizing the radically polymerizable composition according to claim 1 , wherein the polymer has a refractive index (n _D ) at 25° C. of 1.60 or more.

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