JPWO2008111640A1 - Oxetane resin composition - Google Patents

Abstract

Provided are an oxetane resin composition that gives a cured product excellent in transparency, heat resistance, low water absorption, and low dielectric constant, and a cured product obtained therefrom. This oxetane resin composition comprises cycloaliphatic oxetane resin (A) 10 to 88% by weight, cycloaliphatic epoxy resin (B) 10 to 88% by weight, and thermal cationic polymerization initiator (C). 0.01-20 weight part is mix | blended with respect to a total of 100 weight part of oxetane resin (A) and cycloaliphatic epoxy resin (B). Cycloaliphatic oxetane resins (A) include 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl, 1,4-bis [(3-ethyl-3-oxetanyl) methoxy Methyl] cyclohexane or a mixture thereof, and the cycloaliphatic epoxy resin (B) includes 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylsancarboxylate.

Description

  The present invention relates to an oxetane resin composition useful as a sealing material for coating materials, molding or casting, optical materials and electrical insulating materials, semiconductor light emitting devices (LEDs), and the like. This oxetane resin composition gives a cured product excellent in transparency, heat resistance, low water absorption, and low dielectric constant.

  Conventionally, a cationic curing technique by thermal curing or active energy ray curing of an epoxy compound and an oxetane compound is known, and various epoxy compounds, various oxetane compounds, and various cationic polymerization initiators are commercially available. Examples of the epoxy compound include aromatic epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, phenol novolac type epoxy resin, and 3,4-epoxycyclohexylmethyl-3 ′ obtained by peracetic acid oxidation of cycloolefin. , 4′-epoxycyclohexanecarboxylate, and the like, and hydrogenated epoxy resins obtained by hydrogenating bisphenol A diglycidyl ether. Examples of oxetane compounds include 3-ethyl-3-hydroxymethyl oxetane, xylene dioxetane, bis (3-ethyl-3-oxetanylmethyl) ether, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl]. Biphenyl etc.

  In electrical applications, in recent years, electrical circuits have become more multilayered and denser due to miniaturization of electrical equipment. In connection with this, the epoxy resin used for it is required to have a low dielectric constant, arc resistance, and tracking resistance. It is known that cycloaliphatic epoxy resins or hydrogenated epoxy resins having no aromatic ring are more advantageous than aromatic epoxy resins for improving these electrical characteristics. On the other hand, in recent years, light emitting devices such as light emitting diodes (LEDs) that have been put to practical use in various display boards, light sources for image reading, traffic signals, large display units, backlights for mobile phones, etc. are based on aromatic epoxy resins. In general, it is manufactured by sealing with a resin using an alicyclic acid anhydride as a curing agent. However, it is known that this resin system tends to discolor acid anhydrides and requires a long time for curing. Further, when the cured sealing resin is left outdoors or exposed to a light source that generates ultraviolet rays, the sealing resin has a problem such as yellowing.

  As means for solving these problems, as described in Patent Document 1, an epoxy resin obtained by curing hydrogenated bisphenol A glycidyl ether and an alicyclic epoxy monomer by thermal cationic polymerization has been proposed.

  However, in the epoxy polymerization, since the basicity of the oxygen atom on the generated polymer chain is higher than that of the monomer in the cationic polymerization, the oxonium cation at the active end reacts with the oxygen atom in the polymer chain to polymerize. It is known that the degree of polymerization does not increase due to termination. A low degree of polymerization means that the hydroxyl group concentration in the molecular chain is high, which causes an increase in water absorption and an increase in dielectric constant. Moreover, since the hydroxyl group has high reactivity, it causes discoloration due to heat or light.

  Patent Document 2 proposes an oxetane resin composition comprising an aliphatic and cycloaliphatic oxetane and a cationic polymerization initiator. However, a cured product containing only the alicyclic oxetane has a flexible structure and therefore has a low Tg and is not suitable for the above-mentioned use.

JP 2003-73452 A JP 2005-290141 A

  An object of the present invention is to provide a curable oxetane resin composition that gives a cured product excellent in transparency, heat resistance, low water supply rate, and low dielectric constant.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found an oxetane resin composition capable of achieving these objects and have reached the present invention.

  That is, the present invention relates to a cycloaliphatic oxetane resin comprising 10 to 88% by weight of a cycloaliphatic oxetane resin (A), 10 to 88% by weight of a cycloaliphatic epoxy resin (B) and a thermal cationic polymerization initiator (C). An oxetane resin composition comprising 0.01 to 20 parts by weight per 100 parts by weight in total of (A) and the cycloaliphatic epoxy resin (B).

  Here, it is preferable that the molecular weights of the cycloaliphatic oxetane resin (A) and the cycloaliphatic epoxy resin (B) are both in the range of 100 to 2000.

  Cycloaliphatic oxetane resins (A) include 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl, 1,4-bis [(3-ethyl-3-oxetanyl) methoxy Methyl] cyclohexane or mixtures thereof. Examples of the cycloaliphatic epoxy resin (B) include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylsancarboxylate.

  Moreover, this invention is a hardened | cured material obtained by heat-curing the said oxetane resin composition.

Hereinafter, the oxetane resin composition of the present invention will be described in detail.
The oxetane resin composition of the present invention contains a cycloaliphatic oxetane resin (A), a cycloaliphatic epoxy resin (B), and a thermal cationic polymerization initiator (C) as essential components. Here, the cycloaliphatic oxetane resin (A) and the cycloaliphatic epoxy resin (B) may be a single compound or a mixture of compounds having different numbers of repeating units. Accordingly, the aliphatic oxetane resin (A) and the cycloaliphatic epoxy resin (B) may be referred to as an aliphatic oxetane compound and a cycloaliphatic epoxy compound. The cycloaliphatic oxetane resin (A) is also referred to as component (A), the cycloaliphatic epoxy resin (B) as component (B), and the thermal cationic polymerization initiator (C) as component (C).

  The cycloaliphatic oxetane resin (A) used in the present invention is an oxetane resin derived from an alcohol containing an alicyclic structure or obtained by hydrogenating an aromatic ring. In the case of a hydrogenated oxetane resin obtained by hydrogenating an aromatic ring, it refers to an oxetane resin having an aromatic ring hydrogenation rate of 80% or more, preferably a hydrogenation rate of 90% or more. The hydrogenation rate of the aromatic ring in the oxetane resin is the ratio at which the aromatic ring is changed to the alicyclic ring, and can be determined by nuclear magnetic resonance analysis. If the hydrogenation rate of this aromatic ring is less than 80%, the electrical properties and weather resistance of the cured oxetane resin are greatly reduced, which is not preferable.

  Oxetane compounds have a feature that high molecular weight compounds can be obtained in cationic polymerization because oxygen in the molecule is highly basic. For this reason, the hydroxyl group concentration in the molecular chain is lowered, and the characteristics of low water absorption and low dielectric constant are exhibited. Moreover, heat resistance and light resistance are also improved.

  The (A) component cycloaliphatic oxetane resin is a compound having an alicyclic structure and an oxetane group bonded thereto. The molecular weight is 100 or more, preferably 100 to 2000, more preferably 120 to 2000, and still more preferably 150 to 1000. If the molecular weight is too small, the cycloaliphatic oxetane compound is highly volatile, and the working environment and processing characteristics during coating are significantly deteriorated. If the molecular weight is too large, the viscosity of the resin composition increases, and it becomes difficult to cast, mold or uniformly apply the resin composition into a predetermined shape.

  The cycloaliphatic oxetane resin can be easily obtained by selectively hydrogenating the aromatic oxetane resin under pressure in the presence of a catalyst. As the aromatic oxetane resin used here, for example, bisphenol A type oxetane resin, bisphenol F type oxetane resin, bisphenol S type oxetane resin and other bisphenol type oxetane resins, biphenol oxetanyl ether, tetramethylbiphenol oxetanyl ether and the like Biphenol-type oxetane resin, Naphtalene-type oxetane resin such as oxetaneyl ether of naphthol, xylene-type oxetane resin such as oxetanyl ether of bishydroxymethylbenzene, dimethylbiphenyl-type oxetane resin such as oxetanyl ether of bishydroxymethylbiphenyl, bishydroxymethylnaphthalene Dimethyl naphthalene type oxetane resin such as oxetanyl ether, dioxe cyclohexanedicarboxylate Polyesters such as ester resin, phenol novolak oxetane resin, cresol novolak oxetane resin, novolak oxetane resin such as hydroxybenzaldehyde phenol novolak oxetane resin, oxetanyl ether of tetrahydroxyphenylmethane, oxetanyl ether of tetrahydroxybenzophenone and oxetanilated polyvinylphenol Examples include oxetane resins.

  Specific examples of the cycloaliphatic oxetane resin include compounds represented by the following formulas (1) to (8).

  Among these, due to the availability of raw materials, etc., 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] cyclohexane represented by the formula (1) or represented by the formula (2) 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl is preferred.

  The cycloaliphatic epoxy resin as component (B) is preferably obtained by epoxidizing a cycloolefin.

  The cycloaliphatic epoxy resin as component (B) is a compound in which an epoxy group is bonded to an aliphatic ring. The molecular weight is 100 or more, preferably 100 to 2000, more preferably 120 to 2000, and still more preferably 120 to 1000. If the molecular weight is too small, the cycloaliphatic epoxy resin has high volatility, and the working environment and processing characteristics during coating are remarkably deteriorated. If the molecular weight is too large, the viscosity of the resulting composition will be high, and it will be difficult to cast, mold or evenly apply to a predetermined shape.

  Specific examples of the cycloaliphatic epoxy resin include a compound represented by the formula (9) (for example, CEL2021P manufactured by Daicel Chemical Industries) and a compound represented by the formula (10) (for example, Araldite CY178 manufactured by Asahi Ciba). ), A compound represented by the formula (11) (for example, Chissonox 206 manufactured by Chisso), a compound represented by the formula (12) (for example, Chissonox 205 manufactured by Chisso), and the formula (13 ) To the compound represented by formula (18). Among these, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate represented by the formula (9) is effective in reducing the viscosity and improving the heat resistance of the composition of the present invention. Is preferable.

  As the thermal cationic polymerization initiator of component (C), any can be used as long as it generates cationic species such as Bronsted acid and Lewis acid by heating. For example, organosilane and organoaluminum compound catalysts, onium salts such as sulfonium salts and phosphonium salts, and heteropolyacids can be used. The temperature at which the cationic species is generated varies depending on the catalyst, but in many cases, it is 50 ° C. or higher, and it is preferable to use one having a temperature of 100 ° C. or higher because of storage stability at room temperature.

  Specifically, the organosilane is monofunctional such as methoxytrimethylsilane, ethoxytriethylsilane, propoxytripropylsilane, butoxytributylsilane, methoxytrioctylsilane, methoxytriphenylsilane, methoxytribenzylsilane, triphenylhydroxysilane and the like. Silane compounds; dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydibutylsilane, dipropoxydipropylsilane, dimethoxydilaurylsilane, dimethoxydiphenylsilane, dimethoxydibenzylsilane, methoxybenzyloxydipropylsilane, methoxy-2-ethylhexyloxydipropyl Bifunctional silane compounds such as silane and diphenylsilanediol; trimethoxymethylsilane, triethoxyethylsilane, Trifunctional silane compounds such as lopoxypropylsilane, trimethoxystearylsilane, trimethoxyphenylsilane, trimethoxybenzylsilane, methoxydibenzyloxypropylsilane, methoxytrihydroxysilane, phenyltrihydroxysilane; tetramethoxysilane, tetraethoxysilane Tetrafunctional silane compounds such as tetrapropoxysilane, tetrabutoxysilane, trimethoxybenzyloxysilane, dimethoxydi-2-ethylhexylsilane, tetrahydroxysilane; low-condensates of the above trifunctional silane compounds and / or tetrafunctional silane compounds (about 2 to 50-mer); vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane Reactive silicon group-containing ethylenically unsaturated monomers such as γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, β- (meth) acryloyloxyethylpropyltrimethoxysilane And if necessary, (co) polymers with the above-mentioned other radical polymerizable unsaturated monomers may be mentioned. The above compounds can be used alone or in combination of two or more. Examples of the low-condensate (about 2 to 50 mer) of the above-described trifunctional silane compound and / or tetrafunctional silane compound include SH6018 (manufactured by Toray Silicone Co., Ltd .: hydroxyl group equivalent 400, molecular weight 1600 methylphenylpolysiloxane), etc. A silicone resin available under the trade name of can also be used. From the viewpoint of reactivity and availability, a silicone resin available under trade names such as triphenylsilanol and SH6018 is preferable.

  As the organoaluminum compound, an alkoxide, a chelated product, or the like can be used. Specifically, for example, alkoxides such as aluminum triethoxide, aluminum triisopropoxide, aluminum-sec-butyrate, ethyl acetoacetate aluminum diisopropylate, tris (ethyl acetoacetate) aluminum, tris (propyl acetate) aluminum Of keto-enol tautomers such as tris (butylacetoacetate) aluminum, propoxybis (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, tris (propionylacetonato) aluminum, tris (acetoacetonato) aluminum Compounds and the like. These can be used alone or in combination of two or more. Of these, aluminum triisopropoxide, ethyl acetoacetate aluminum diisopropylate, and tris (acetoacetonato) aluminum are preferred in view of curability and economy.

  Examples of phosphonium salts include benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate. Benzyl-4-methoxyphenylmethylsulfonium hexafluoroantimonate, benzyl-2-methyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroarsenate, benzyl -3-Methyl-4-hydroxy-5-tert-butylphenylmethylsulfonium hexafluoroantimonate 4-methoxybenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate, 4-acetoxyphenyldibenzylsulfonium hexafluoroantimonate, Dibenzyl-4-methoxyphenylsulfonium hexafluoroantimonate, nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 3,5-dinitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, β-naphthylmethyl-4 -Hydroxyphenylmethylsulfonium hexafluoroantimonate and the like. Examples of commercially available sulfonium salts include Sun-Aid SI-L85, Sun-Aid SI-L110, Sun-Aid SI-L145, Sun-Aid SI-L160, Sun-Aid SI-H15, Sun-Aid SI-H20, Sun-Aid SI-H25, Sun-Aid SI-H40, Sun-Aid SI-H50, Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L, Sun-Aid SI-80, Sun-Aid SI-100 (manufactured by Sanshin Chemical Industry Co., Ltd., trade name), CP-77 (manufactured by ADEKA Corporation) ) And the like. From the viewpoint of availability, Sun-Aid SI, CP-77 is preferable.

  As for heteropolyacids, for example, molybdenum (VI) and tungsten (VI) ions become oxoacids in water. These oxo acids are polymerized into high molecular polyoxo acids. At this time, not only the same kind of oxo acid is polymerized, but another kind of oxo acid may be polymerized around a certain oxo acid. Such a compound is called a heteropolyacid. The element that forms the central oxo acid is called a hetero element, and the oxo acid element that polymerizes around it is called a poly element. Examples of hetero elements include Si, P, As, S, Fe, and Co. Examples of poly elements include Mo, W, and V. Since there are a large number of polyelements relative to heteroelements at the time of polymerization, many heteropolyacids can be produced by combining them. In the present invention, such a heteropolyacid can be used without particular limitation.

  From the viewpoint of curing performance and availability, phosphotungstic acid, phosphomolybdic acid, silicotungstic acid and silicomolybdic acid are preferred, and silicotungstic acid and silicomolybdic acid are more preferred. These salts, sodium salts, cesium salts, ammonium salts, pyridinium salts, and the like can also be used.

  The curable oxetane resin composition of the present invention comprises (A) component 10 to 88% by weight, preferably 25 to 75% by weight, and (B) component 10 to 88% by weight, preferably 25 to 75% by weight. Component C) is contained in an amount of 0.01 to 20 parts by weight, preferably 0.02 to 10 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of component (A) and component (B).

  From another viewpoint, it is preferable to use 10 to 200 parts by weight, preferably 25 to 75 parts by weight, of component (B) with respect to 50 parts by weight of component (A). This component (B) is effective for improving the heat resistance of the cured product. When the amount of the cycloaliphatic epoxy resin as the component (B) is less than 10% by weight, the effect of improving the heat resistance of the cured product is reduced, and when it exceeds 90% by weight, the cured product becomes brittle. Component (C) in the composition is 0.02 to 10% by weight, preferably 0.1 to 2% by weight. In this case, the component (A) contains 20 to 70% by weight, preferably 25 to 75% by weight, and the component (B) contains 20 to 70% by weight, preferably 23 to 73% by weight.

  The thermal cationic polymerization initiator of component (C) is blended in an amount of 0.01 to 20 parts by weight with respect to a total of 100 parts by weight of the cycloaliphatic oxetane resin of component (A) and the cycloaliphatic epoxy resin of component (B). . If the content of the thermal cation curing catalyst is excessive, the storage stability may be lowered. On the other hand, when the thermal cation curing catalyst is too small, the curing rate is lowered and the composition is not sufficiently cured.

  In the oxetane resin composition of the present invention, various curable monomers, oligomers and synthetic resins may be blended as components other than the components (A) to (C) as necessary for the purpose of improving the properties of the resin. Can do. Examples include diluents for epoxy resins such as monoepoxy, diols or triols, vinyl ethers, oxetane compounds other than the component (A), fluororesins, acrylic resins, silicone resins, polyester resins, and the like. However, since the blending ratio of these components may impair the original properties of the resin composition of the present invention, it is preferably 30% by weight or less of the resin composition, particularly in the range of 20% by weight or less. Is preferred.

  In addition, the oxetane resin composition of the present invention can be blended with an inorganic filler, but these uses may impair the transparency that is a feature of the present invention, so that this does not impair this, For example, surface-treated silica particles having a very small particle size are suitable. Also when using this, it is preferable that it is 40 weight part or less with respect to 100 weight part of resin compositions, and the use in 20 weight part or less is especially preferable. In addition, the filler such as an inorganic filler to be blended in a large amount and the diluent such as a solvent are preferably calculated as the external number of the oxetane resin composition.

  Further, in the resin composition of the present invention, other additives such as a colorant such as a pigment, a flame retardant, a coupling agent, and a stabilizer other than the above can be blended depending on the purpose.

  The oxetane resin composition of the present invention is blended with the above components (A) to (C) as necessary, using heat melting and mixing, melting and kneading with a roll and a kneader, and an appropriate organic solvent. Can be produced by wet mixing and dry mixing.

  The oxetane resin composition produced in this way is cured by heat and becomes the cured product of the present invention. In the case of thermal cationic polymerization, the thermal cationic polymerization initiator is usually performed at a temperature at which the generation of cationic species or Lewis acid is started, and is usually performed at 50 to 200 ° C.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Abbreviations are as follows:
BMBH: 4,4'-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl
CEL2021P: 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (Daicel Chemical CEL2021P)

Example 1
50 parts by weight of BMBH, 50 parts by weight of CEL2021P, and 0.335 parts by weight of CP-77 (Sulphonium salt cationic polymerization initiator manufactured by Adeka Co., Ltd.) were stirred and mixed at room temperature to be uniform, then degassed under reduced pressure, and oxetane resin A composition was obtained.

Example 2
Stir at room temperature so that 50 parts by weight of BMBH, 50 parts by weight of CEL2021P, 0.5 parts by weight of aluminum acetylacetonate (Tokyo Chemical Industry Co., Ltd.) and 0.5 parts by weight of triphenylsilanol (manufactured by Tokyo Chemical Industry Co., Ltd.) can be evenly mixed. After mixing, degassed under reduced pressure to obtain an oxetane resin composition.

Example 3
50 parts by weight of 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] cyclohexane, 50 parts by weight of CEL2021P, and 0.67 parts by weight of CP-77 were stirred and mixed at room temperature. Foaming was performed to obtain an oxetane resin composition.

Example 4 (comparison)
50 parts by weight of hydrogenated bisphenol A diglycidyl ether (manufactured by Ube Industries, Ltd.), 50 parts by weight of CEL2021P, and 0.335 parts by weight of CP-77 were stirred and mixed at room temperature. A resin composition was obtained.

  Each resin composition obtained in Examples and Comparative Examples was poured into a mold and heated in an oven at 60 ° C. for 4 hours and further at 150 ° C. for 2 hours to obtain a cured product. These cured products were tested for glass transition point, initial transmittance, heat resistance, bending strength, hygroscopicity, and dielectric constant. The results are shown in Table 1.

  The glass transition point (Tg) is determined by the DMA method. As the initial transmittance, a 400 nm transmittance of a cured product having a thickness of 4 mm was measured. For heat resistance, the cured product was kept in air at 150 ° C. for 24 hours, and then the transmittance at 400 nm was measured in the same manner as the initial transmittance. The bending strength was measured by the method described in JIS6911. The hygroscopicity was measured under the conditions of 85 ° C., 85% RH and 100 hours. The dielectric constant is measured at 2 GHz in the cavity resonator perturbation method.

Industrial applicability

  According to the present invention, an oxetane resin composition that provides a cured product excellent in transparency, heat resistance, low water supply rate, and low dielectric constant can be obtained. This oxetane resin composition can be used in a wide range of applications as a coating material, an optical material obtained by molding or casting, and an electrical insulating material. Moreover, it can use suitably as sealing resin of light-emitting devices, such as an optical semiconductor (LED), making use of the characteristic of the transparency and low thermochromic property.

Claims (5)

  Cyclic aliphatic oxetane resin (A) 10-88% by weight, cyclic aliphatic epoxy resin (B) 10-88% by weight, and thermal cationic polymerization initiator (C) are cyclic with cyclic aliphatic oxetane resin (A). An oxetane resin composition comprising 0.01 to 20 parts by weight based on a total of 100 parts by weight of the aliphatic epoxy resin (B).   The oxetane resin composition according to claim 1, wherein the cycloaliphatic oxetane resin (A) and the cycloaliphatic epoxy resin (B) each have a molecular weight in the range of 100 to 2,000.   Cycloaliphatic oxetane resin (A) is 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl The oxetane resin composition according to claim 1, which is cyclohexane or a mixture thereof.   The oxetane resin composition according to claim 1, wherein the cycloaliphatic epoxy resin (B) is 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexylsancarboxylate.   Hardened | cured material obtained by heat-hardening the oxetane resin composition in any one of Claims 1-4.