JP2005298587A - Resin composition for optical material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for an optical material, capable of giving a cured product having a relatively low refractive index and given by using a thiirane compound. <P>SOLUTION: This resin composition for the optical material contains the thiirane compound and a curing agent and gives the cured product having a refractive index of ≤1.70, wherein the thiirane compound does not contain an aromatic ring in its molecule and contains two or more radicals, in total, which are expressed by formula (1) and/or expressed by formula (2), provided that at least one of the radicals is a radical expressed by formula (1), and the curing agent comprises at least one kind selected from a group comprising an acid anhydride compound, an imidazole compound, and a phenol resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition for optical materials.

Epoxy compounds and thiirane compounds (episulfide compounds) are widely used as optical materials having excellent physical strength, heat resistance, chemical resistance, electrical insulation, and the like. For example, in Patent Document 1, one or more thirane rings and a structure represented by —Y—C (═X) —NH— (X and Y each represents O or S) are included in one molecule. An episulfide compound is described.
However, since the optical material using the compound described in Patent Document 1 has a relatively high refractive index, it is not suitable for applications such as an adhesive for optical fibers.

JP 2003-26674 A

  Therefore, an object of the present invention is to provide a resin composition for an optical material from which a cured product having a relatively low refractive index can be obtained.

As a result of intensive studies on the use of epoxy compounds and thiirane compounds as optical materials, the present inventors have found the following.
First, when comparing an epoxy compound having an aromatic ring, which is widely used as an epoxy compound, and a thiirane compound in which the oxirane ring is substituted with a thiirane ring, the epoxy compound generally has a lower refractive index of the cured product. On the other hand, when comparing an epoxy compound having no aromatic ring and a thiirane compound in which the oxirane ring is substituted with a thiirane ring, when the resin is cured using a specific curing agent, the refractive index of the cured product We found that there was almost no difference in rate. That is, it was found that the refractive index of the cured product can be lowered by using a thiirane compound having no aromatic ring.
In addition, the present inventor has found that, when comparing an epoxy compound having no aromatic ring and a thiirane compound in which the oxirane ring is substituted with a thiirane ring, the thiirane compound can be cured faster at a lower temperature. It was.
Furthermore, the present inventor shows that the compound described in Patent Document 1 has a high refractive index because a sulfur atom (—S—) or an imino group (—NH—) is bonded to a methylene group bonded to a thiirane ring. It has been found that the refractive index can be lowered by bonding an oxygen atom (—O—) to this methylene group.
And this inventor completed this invention based on these knowledge.

  That is, the present invention provides the following (i) to (iv).

(I) The molecule does not contain an aromatic ring and contains a total of two or more groups represented by the following formula (1) and / or the following formula (2), one of which is represented by the following formula A thiirane compound which is a group represented by (1);
Containing at least one curing agent selected from the group consisting of an acid anhydride compound, an imidazole compound and a phenol resin,
The resin composition for optical materials whose refractive index of hardened | cured material is 1.70 or less.

  (Ii) The resin composition for an optical material according to the above (i), further comprising an inorganic compound having one or more sulfur atoms and / or selenium atoms.

  (Iii) The resin composition for an optical material according to the above (i) or (ii), further containing a phosphite.

  (Iv) The resin composition for optical materials according to (iii), wherein the phosphite is diphenyldecyl phosphite.

  In the resin composition for an optical material of the present invention, the refractive index of the obtained cured product is lower than that of a conventional thiirane compound. Moreover, the resin composition for optical materials of the present invention can be cured at a relatively low temperature and at a high curing rate.

The present invention is described in detail below.
The thiirane compound used in the present invention does not include an aromatic ring in the molecule, and includes a total of two or more groups represented by the following formula (1) and / or the following formula (2), One or more is a thiirane compound which is a group represented by the following formula (1).

Since the thiirane compound used in the present invention does not contain an aromatic ring in the molecule, the cured product has a low refractive index.
In addition, the thiirane compound used in the present invention includes two or more groups in total in the molecule represented by the above formula (1) and / or the above formula (2), and one or more of them It is group represented by the said Formula (1). In the group represented by the above formula (1), since the oxygen atom is bonded to the methylene group bonded to the thiirane ring, the refractive index of the cured product is lower than when the sulfur atom or the imino group is bonded. Become.

  The configuration of the thiirane compound used in the present invention is not particularly limited except the points described above. For example, a thiirane compound represented by the following formula (3), wherein at least one Y is a group represented by the following formula (4), and the remaining Y is a group represented by the following formula (5). It is done.

(In the formula, R represents a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group which may contain an oxygen atom, a nitrogen atom and a sulfur atom.)

  Specifically, for example, it is represented by the following formulas (a) to (j), at least one Y is a group represented by the above formula (4), and the remaining Y is represented by the above formula (5). Each thiirane compound which is a group to be used is exemplified.

  In addition, these thiirane compounds may be those in which a hydrogen atom is substituted with a halogen atom. Examples of the halogen atom include a bromine atom, a chlorine atom, and a fluorine atom.

The thiirane compound used in the present invention can be obtained, for example, by a method of replacing the oxirane ring of the corresponding epoxy compound with a thiirane ring.
Specifically, thiirane represented by the above formula (3), wherein at least one Y is a group represented by the above formula (4), and the remaining Y is a group represented by the above formula (5). In the case of obtaining a compound, an epoxy compound represented by the above formula (3) and all Y being groups represented by the above formula (5) is used.

  Similarly, it is represented by the above formulas (a) to (j), and at least one Y is a group represented by the above formula (4), and the remaining Y is a group represented by the above formula (5). When obtaining each thiirane compound, each epoxy compound represented by the above formulas (a) to (j) and all Y being groups represented by the above formula (5) is used. The same applies when a hydrogen atom is substituted with a halogen atom.

The thiirane compound used in the present invention can be produced by a method in which the above-described epoxy compound and episulfiding agent are reacted under strong stirring in a polar solvent.
Examples of the episulfiding agent include potassium thiocyanate (KSCN) and thiourea.
Examples of the polar solvent include methanol, ethanol, acetone, water, and mixed solvents thereof.

  The reaction can be usually performed in a temperature range of 10 to 35 ° C., for example, at room temperature for about 10 to 40 hours, for example, for about 20 hours. The reaction atmosphere may be air or an inert atmosphere such as nitrogen.

  The thiirane compound used in the present invention may have only a thiirane ring or may contain both a thiirane ring and an oxirane ring.

In the resin composition for optical materials of the present invention, two or more thiirane compounds described above can be used in combination. In this case, both a thiirane compound having only a thiirane ring and a thiirane compound having both a thiirane ring and an oxirane ring can be contained.
Moreover, the resin composition for optical materials of this invention may contain the unreacted epoxy compound used for manufacture of a thiirane compound.

  The ratio of the oxirane ring / thiirane ring in the resin composition for optical materials of the present invention is preferably in the range of 90/10 to 0/100 in that a sufficiently high curing rate can be obtained.

  The curing agent used in the present invention is at least one selected from the group consisting of an acid anhydride compound, an imidazole compound, and a phenol resin. When these hardening | curing agents are used, the resin composition for optical materials of this invention can be made into 1 liquid type. That is, the resin composition for an optical material of the present invention has sufficient storage stability at room temperature and is cured by heating.

  Examples of the acid anhydride compound include phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerol tris (androtrimellitate), pyromellitic anhydride, 3,3 ′, 4, Aromatic acid anhydride compounds such as 4'-benzophenone tetracarboxylic acid anhydride; maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, alkenyl succinic anhydride, hexahydrophthalic anhydride Cyclic aliphatic acid anhydride compounds such as acid, methylhexahydrophthalic anhydride, methylcyclohexenetetracarboxylic anhydride, methylhymic anhydride, trialkyltetrahydrophthalic anhydride, poly (phenylhexadecanedioic anhydride); polyadipine Acid anhydride, polyazerai Aliphatic acid anhydride compounds such as acid anhydrides, polysebacic acid anhydrides, dodecenyl succinic acid anhydrides, poly (ethyloctadecanedioic acid) anhydrides; halogenated acids such as chlorendic acid anhydrides, tetrabrom phthalic anhydrides, and het acid anhydrides Anhydrous compounds are mentioned.

  Examples of the imidazole compound include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl. 2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-methylimidazolium isocyanurate, 2,4-diamino-6- [2-methylimidazoline- (1)]-ethyl-s -Triazine, 2,4-diamino-6- [2-ethyl-4-methylimidazoline- (1)]-ethyl-s-triazine.

  A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the present invention, together with these curing agents, conventionally known as an epoxy resin curing agent, an amine curing agent, an acid curing agent, a basic active hydrogen compound, a polymercaptan curing agent, a urea resin, a melamine resin, An isocyanate curing agent, a latent curing agent, an ultraviolet curing agent, and the like can be used in combination.

Moreover, the resin composition for optical materials of this invention may mix | blend a hardening accelerator other than the said hardening | curing agent. Examples of the curing accelerator include phenols and tertiary amines.
Among these, tertiary amines are excellent in curing acceleration effect.
A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

  Moreover, it is preferable that the resin composition for optical materials of this invention contains a phosphite. When the phosphite is contained, the stability of the main agent (thiirane compound) during storage becomes excellent, and coloring after curing is suppressed.

Examples of phosphites include triphenyl phosphite, tris (nonylphenyl) phosphite, triethyl phosphite, tributyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, and tris (tridecyl) phosphite. , Diphenyl mono (2-ethylhexyl) phosphite, diphenyl decyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, trilauryl trithiophosphite , Bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, tristearyl phosphite Distearyl pentaerythritol diphosphite, tris (2,4-di -t - butyl phenyl) phosphite, hydrogenated bisphenol A · pentaerythritol phosphite triester such polymers.
Moreover, the diester body or monoester body which hydrolyzed these triester bodies partially is also mentioned.

  Among these, diphenyldecyl phosphite is preferable in that it can improve storage stability without adversely affecting the curing.

  The resin composition for an optical material of the present invention can contain an inorganic compound having at least one sulfur atom and / or selenium atom in order to adjust the refractive index of the cured product. In this inorganic compound, the proportion of the total mass of sulfur atoms and / or selenium atoms in the inorganic compound is preferably 10 to 90%. Within the above range, the refractive index can be easily adjusted.

  Specific examples of the inorganic compound containing a sulfur atom include elemental sulfur, hydrogen sulfide, carbon disulfide, carbon selenosulfide, ammonium sulfide, sulfur oxide (eg, sulfur dioxide, sulfur trioxide), thiocarbonate, sulfuric acid and its Salt, hydrogen sulfide, sulfite, hyposulfite, persulfate, thiocyanate, thiosulfate, halide (eg, sulfur dichloride, thionyl chloride, thiophosgene), boron sulfide, nitrogen sulfide, silicon sulfide, sulfide Examples include phosphorus, arsenic sulfide, selenium sulfide, metal sulfide, and metal hydrosulfide.

  Specific examples of the inorganic compound containing a selenium atom include selenium sulfide, selenium sulfide, selenium sulfide, hydrogen selenide, selenium dioxide, carbon diselenide, ammonium selenide, selenium oxide (for example, Selenium dioxide), selenic acid and its salts, selenious acid and its salts, hydrogen selenate, selenosulfuric acid and its salts, selenopyrosulfuric acid and its salts, selenium tetrabromide, halides (eg selenium oxychloride), selenocyan Examples thereof include acid salts, boron selenide, phosphorus selenide, arsenic selenide, and metal selenides.

  An inorganic compound having one or more sulfur atoms and / or selenium atoms may be used alone or in combination of two or more.

  The resin composition for an optical material of the present invention can contain various additives as necessary in addition to the above various components within a range not impairing the object of the present invention. Examples of additives include fillers, plasticizers, softeners, thixotropy imparting agents, pigments, dyes, anti-aging agents, antioxidants, antistatic agents, flame retardants, adhesion imparting agents, dispersants, and solvents. Can be mentioned.

  As the filler, those having various shapes can be used. For example, fumed silica, calcined silica, precipitated silica, ground silica, fused silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; calcium carbonate, magnesium carbonate, zinc carbonate; Examples include kaolin clay, calcined clay; organic or inorganic fillers such as carbon black; these fatty acids, resin acids, fatty acid ester-treated products, and fatty acid ester urethane compound-treated products.

  Examples of the plasticizer or softener include diisononyl phthalate, dioctyl phthalate, dibutyl phthalate; dioctyl adipate, isodecyl succinate; diethylene glycol dipenzoate, pentaerythritol ester; butyl oleate, methyl acetylricinoleate; phosphorus Examples include petroleum-based softeners such as tricresyl acid, trioctyl phosphate; propylene glycol polyester adipate, butylene glycol polyester adipate; paraffinic oil, naphthenic oil, and aromatic oil.

Examples of the thixotropic agent include dry silica, white carbon, hydrogenated castor oil, surface-treated calcium carbonate, Teflon (registered trademark), amide wax, and various bentonite clay compounds.
Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride and sulfate; organic pigments such as azo pigments and copper phthalocyanine pigments. It is done.

Examples of the antiaging agent include hindered phenol compounds and hindered amine compounds.
Examples of the antioxidant include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).
Examples of the antistatic agent include quaternary ammonium salts; hydrophilic compounds such as polyglycols and ethylene oxide derivatives.

Examples of the flame retardant include chloroalkyl phosphate, dimethyl / methylphosphonate, bromine / phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, and brominated polyether.
Examples of the adhesion imparting agent include terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins, and epoxy resins.
The above additives can be used in combination as appropriate.

  The resin composition for an optical material of the present invention is cured by heating. The resin composition for an optical material of the present invention is preferably curable at a temperature of 40 ° C. or higher and lower than 180 ° C., more preferably curable at a temperature of 60 ° C. or higher and 160 ° C. or lower. When it is in the above range, it can be used easily and consumes less energy.

  In the resin composition for an optical material of the present invention, the cured product has a refractive index of 1.70 or less, preferably less than 1.65. When the refractive index of the cured product is in the above range, it is suitably used for applications such as an adhesive for optical fibers. The refractive index of the cured product is more preferably 1.35 or more and less than 1.65.

Moreover, it is preferable that the hardened | cured material is transparent in the resin composition for optical materials of this invention. Specifically, the haze specified in JIS K7136: 2000 is preferably 40% or less, more preferably 30% or less, and even more preferably 20% or less. When the cured product is transparent, it is suitably used for various optical material applications.
Moreover, it is preferable that the hardened | cured material is colorless in the resin composition for optical materials of this invention. When the cured product is colorless, it is suitably used for various optical material applications.

  The resin composition for optical materials of the present invention is used for optical materials such as optical material parts and optical material adhesives. Specifically, for example, a lens, a prism, an optical fiber, an optical circuit element, an information recording base, a filter, a film, an optical disk substrate, a light emitting element (laser, LED), a light receiving element, a solar cell, an optoelectronic integrated circuit (OEIC), light Sensor, display element (liquid crystal, LED, PDP, EL), recording element (optical disk), hologram, optical communication device (optical switch, optical transceiver, multiplexer / demultiplexer, coupler, attenuator), sensor (photoelectric switch, optical fiber sensor) , Laser light sources), microlens arrays; these sealants, coating agents and adhesives.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
1. Synthesis of thiirane compound (1) Hydrogenated bisphenol A type thiirane compound 68 g of potassium thiocyanate is dissolved in a mixed solvent of 75 ml of ethanol and 100 ml of water, and is further represented by the above formula (a). 150 g of the hydrogenated bisphenol A type epoxy compound represented by 4) (EP-4080, manufactured by Asahi Denka Kogyo Co., Ltd.) was added dropwise and stirred vigorously at room temperature for 40 hours.
Subsequently, extraction with toluene was performed, followed by washing with water and drying with magnesium sulfate. Further, toluene was distilled off under reduced pressure, followed by drying under reduced pressure to obtain a reaction mixture.

  The substitution ratio of the obtained reaction mixture (hereinafter referred to as “hydrogenated bisphenol A type thiirane compound”) from the oxirane ring to the thiirane ring was measured by NMR to be 97%.

(2) Bisphenol A type thiirane compound 68 g of potassium thiocyanate is dissolved in a mixed solvent of 75 mL of ethanol and 100 mL of water, and is further represented by the following formula (k), and all Y are represented by the above formula (5). 170 g of bisphenol A type epoxy compound (EP-4100E, manufactured by Asahi Denka Kogyo Co., Ltd.) was added dropwise and stirred vigorously at room temperature for 40 hours.
Subsequently, extraction with toluene was performed, followed by washing with water and drying with magnesium sulfate. Further, toluene was distilled off under reduced pressure, followed by drying under reduced pressure to obtain a reaction mixture.

  The substitution rate from the oxirane ring to the thiirane ring of the obtained reaction mixture (hereinafter referred to as “bisphenol A type thiirane compound”) was 50% as measured by NMR.

2. Preparation of resin composition (Example 1)
100 parts by mass of the hydrogenated bisphenol A type thiirane compound (main agent) obtained above and 38 parts by mass of methylhexahydrophthalic anhydride (curing agent) were mixed to obtain a resin composition.
(Example 2)
100 parts by mass of the hydrogenated bisphenol A type thiirane compound (main agent) obtained above, 38 parts by mass of methylhexahydrophthalic anhydride (curing agent), and diphenyldecyl phosphite (stable amount of 1% by mass of the total amount) Agent) was mixed to obtain a resin composition.

(Comparative Example 1)
100 parts by mass of the hydrogenated bisphenol A type epoxy compound (main agent) represented by the above formula (1) and 41 parts by mass of methylhexahydrophthalic anhydride (curing agent) were mixed to obtain a resin composition.
(Comparative Example 2)
100 parts by mass of the bisphenol A type epoxy compound (main agent) represented by the above formula (2) and 40 parts by mass of methylhexahydrophthalic anhydride (curing agent) were mixed to obtain a resin composition.
(Comparative Example 3)
100 parts by mass of the bisphenol A type thiirane compound (main agent) obtained above and 37 parts by mass of methylhexahydrophthalic anhydride (curing agent) were mixed to obtain a resin composition.

3. Evaluation of Resin Composition Each resin composition obtained above was evaluated by the following method.
(1) Refractive index of cured product A sheet having a thickness of about 1 mm is prepared from the resin composition, and is 160 ° C. (for Examples 1 and 2 and Comparative Example 3) or 180 ° C. (for Comparative Examples 2 and 3). For 30 minutes to obtain a sheet-like cured product. About the obtained hardened | cured material, the refractive index was measured using the Abbe refractometer.
The results are shown in Table 1.

(2) Stability of main agent The viscosity of only the main agent of the resin composition was measured, and then only the main agent of the resin composition was sealed in a sealed container and allowed to stand at 70 ° C. for 24 hours, and then the viscosity was measured. The viscosity after storage was divided by the viscosity immediately after preparation, and the viscosity change magnification was calculated to evaluate the stability of the main agent. The viscosity was measured at 20 ° C. using an E-type viscometer 3 degree cone.
The results for Examples 1 and 2 and Comparative Example 1 are shown in Table 1.

(3) Curability The resin composition was allowed to stand at the temperature and time shown in Table 1, and the curing state after standing was visually observed to evaluate the curability.
The results for Examples 1 and 2 and Comparative Example 1 are shown in Table 1.

  As is clear from Table 1, the resin composition for optical materials of the present invention (Examples 1 and 2) uses a thiirane compound, but the refractive index of the cured product uses a corresponding epoxy compound. It is equivalent to (Comparative Example 1). Here, in Comparative Example 2 and Comparative Example 3 having the same relationship, it can be seen that when the thiirane compound is used, the refractive index of the cured product is larger than when the corresponding epoxy compound is used. Therefore, it can be said that the resin composition for optical materials of the present invention (Examples 1 and 2) can reduce the refractive index of the cured product despite using the thiirane compound.

Moreover, the resin composition for optical materials of the present invention (Examples 1 and 2) is excellent in the stability of the main agent.
Furthermore, the resin composition for optical materials of the present invention (Examples 1 and 2) is cured at a lower temperature than when the corresponding epoxy compound is used (Comparative Example 1), and a transparent cured product is obtained. I understand. In particular, when phosphite is used (Example 2), it can be seen that there is no coloration even when cured at a high temperature.

Claims (4)

The molecule does not contain an aromatic ring and contains a total of two or more groups represented by the following formula (1) and / or the following formula (2), one or more of which are represented by the following formula (1) A thiirane compound that is a group represented by:
Containing at least one curing agent selected from the group consisting of an acid anhydride compound, an imidazole compound and a phenol resin,
The resin composition for optical materials whose refractive index of hardened | cured material is 1.70 or less.

  Furthermore, the resin composition for optical materials of Claim 1 containing the inorganic compound which has 1 or more of a sulfur atom and / or a selenium atom.   Furthermore, the resin composition for optical materials of Claim 1 or 2 containing a phosphite.   The resin composition for an optical material according to claim 3, wherein the phosphite is diphenyldecyl phosphite.