JP2009235196A - Curable resin composition, cured product thereof, optical member, and optical unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition capable of keeping a refractive index of a cured product produced by curing the curable resin composition and capable of improving a curing rate, reducing curing shrinkage, and lowering viscosity for efficiently producing the cured product such as an optical member. <P>SOLUTION: The curable resin composition includes a (meth)acrylate having a conjugate structure consisting of 7 or more carbon atoms and a radical polymerization initiator. The curable resin composition also includes a cationic polymerizable liquid compound having an aromatic structure as an essential component. The cured product produced by curing the curable resin composition, the optical member containing the cured product, and an optical unit having the optical member are also provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a curable resin composition, a cured product thereof, an optical member, and an optical unit. More specifically, the present invention relates to a curable resin composition useful for optical applications such as lens units and optical device applications, a cured product thereof, and an optical member and an optical unit configured thereby.

The curable resin composition is used as a so-called plastic material for machine part materials, electrical / electronic parts materials, automobile parts materials, civil engineering and building materials, molding materials, and the like, and is also used as a material for paints and adhesives. In recent years, plastic molding materials have attracted attention from the viewpoints of light weight and workability, and application has been attempted in various fields. One example is the application to the field of optical technology. In this field, for example, a digital camera module is mounted on a mobile phone. Instead of glass, plastic lenses such as PMMA / PC and polycycloolefin are being used. Furthermore, as new applications, there is a growing need for in-vehicle use such as in-vehicle cameras and barcode readers for home delivery companies.

Thus, application of a curable resin composition as a plastic molding material or the like to the optical field has been studied. However, it can be adapted to the recent reduction in size and weight, and high performance in optical characteristics is required, but this high required performance cannot be achieved with some conventional plastic materials. For example, particularly in lens applications, from the viewpoint of cost reduction, in order to improve productivity, excellent curing characteristics, workability, moldability, and the like are required, and at the same time, a high refractive index is required. However, no material has been found that can achieve all of these problems and achieve all of them.

As a conventional curable resin composition, a composition capable of radical polymerization having a fluorene-based compound as a main component is disclosed for a plastic lens material (see, for example, Patent Document 1). This composition uses a fluorene acrylate having a diacrylate structure and forms a plastic lens by radical polymerization. A (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms such as fluorene acrylate having a diacrylate structure has a very high viscosity and is heated when a radical polymerization initiator as a curing agent is blended. Although necessary, the radical polymerization initiator is decomposed by heat and generates radicals, which may cause a problem during the production of a cured product. This composition uses a monofunctional monomer and a low refractive index diacrylate in combination with fluorene acrylate to produce a molded product that copes with the increased viscosity of the resin. There was room for improvement in terms of refractive index fluctuation and higher refractive index. For example, in optical applications, etc., there are high performance requirements for higher refractive index, etc., so it is not only to improve the performance such as curing characteristics, but also to increase the high refractive characteristics and viscosity required for optical applications etc. In addition, there is a demand for a material that can be suitably used as an optical plastic material and the like that have high workability due to the above, excellent curing shrinkage characteristics, and the like, and whose demand is rapidly increasing in recent years.
Japanese Patent No. 3130555 (page 1-2)

The present invention has been made in view of the above-described situation, and has improved workability and reduced viscosity, has excellent workability, and cure shrinkage of the cured product after curing the curable resin composition. It is an object of the present invention to provide a curable resin composition that is capable of efficiently producing a cured product that is used in an optical member while maintaining a high refractive index.

As a result of various studies on curable resin compositions that can be suitably used for various plastic material applications, particularly optical applications, the present inventor has a conjugated structure composed of 7 or more carbon atoms (meta). In the case of using acrylate, it was noted that a cured product having a high refractive index (for example, a refractive index of 1.60 or more) can be obtained due to the conjugated structure. The realization of such a high refractive index is particularly useful in optical applications such as lenses. Moreover, if it is a (meth) acrylate type compound, it can be made the thing excellent in the cure rate.
However, when such a (meth) acrylate compound is used, there are problems such as increasing the viscosity of the resin. In order to solve this problem, a monofunctional monomer or a low refractive index diacrylate is used as described above. Although there was a technology, there were problems of refractive index fluctuation and high refractive index. Therefore, using a (meth) acrylate compound that can realize a high refractive index, realizing a low viscosity without causing the above-mentioned problems, and having excellent workability, productivity, and curing characteristics Therefore, there has been a demand for a curable resin composition that can maintain or improve a high refractive index. As such a curable resin composition, a combination of the above (meth) acrylate compound and a cationic polymerizable liquid compound having an aromatic structure is reduced in viscosity, exhibits excellent curing characteristics, and has high optical properties. The inventors have found that the characteristics can be achieved, and have come up with the idea that the above problems can be solved brilliantly. The cured product obtained from such a curable resin composition has a high refractive index and has a small refractive index fluctuation, so that it can be used in various applications such as optical applications such as lenses, optical device applications, and display device applications. It can be suitably applied to.

That is, the present invention is a curable resin composition containing a (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, and a radical polymerization initiator, wherein the curable resin composition comprises: Furthermore, it is a curable resin composition containing a cationically polymerizable liquid compound having an aromatic structure as an essential component.
The present invention is described in detail below.

The curable resin composition of the present invention contains (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms. Thereby, a high refractive index can be imparted to a cured product obtained by curing the curable resin composition. This is because the electron density of the substance is improved by having a conjugated structure. According to this, since a cured product having a high refractive index can be produced, the cured product can be particularly suitably used for optical applications and the like.

The (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms means (meth) acrylate having 7 or more carbon atoms in one conjugated unit. In other words, it is a (meth) acrylate having 7 or more carbon atoms belonging to an atomic group constituting one conjugated unit and having at least one such conjugated structure.
The conjugated unit is preferably one having a conjugated double bond. More preferably, the conjugated structure contains an aromatic ring. That is, it is more preferable that the (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms has 7 or more carbon atoms constituting the conjugated structure and has an aromatic ring. By being a compound having an aromatic ring, a cured product having a high refractive index when cured can be obtained. In the present specification, (meth) acrylate is an ester of acrylic acid or methacrylic acid, and has at least one acryloyl group or methacryloyl group in one molecule.
Note that the conjugated unit includes at least two double bonds and one single bond, taking a conjugated double bond as an example. When the number of carbon atoms is counted as a single conjugated unit and a bond structure including the unit is shown, a group of portions related to resonance is called one conjugated unit. A preferred form of the conjugated unit will be described later.

The curable resin composition achieves a reduction in viscosity by using a cationic polymerizable liquid compound having an aromatic structure together with a (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, As described above, it can have excellent optical characteristics. Further, in the curable resin composition of the present invention, radical polymerization and cationic polymerization proceed in parallel. However, cationic polymerization also proceeds faster due to heat generated by radical polymerization, and the curing rate is further improved. It becomes. Hereinafter, “(meth) acrylate having a conjugated structure composed of 7 or more carbon atoms” is also simply referred to as “(meth) acrylate having a conjugated structure”.

The content of the (meth) acrylate having a conjugated structure in the curable resin composition of the present invention is preferably 10% by mass or more and 90% by mass or less in 100% by mass of the curable resin composition. If it is less than 10% by mass, the refractive index of the resulting curable resin composition may not be sufficiently high, and if it exceeds 90% by mass, the workability may be reduced due to increased viscosity. More preferably, they are 15 mass% or more and 80 mass% or less, More preferably, they are 20 mass% or more and 70 mass% or less.
Details of the (meth) acrylate having the conjugated structure will be described later.

The content of the radical polymerization initiator in the curable resin composition of the present invention is preferably 0.001% by mass or more with respect to 100% by mass of the curable resin composition. More preferably, it is 0.005 mass% or more, More preferably, it is 0.01 mass% or more, Most preferably, it is 0.1 mass% or more, Preferably it is 30 mass% or less, More preferably, it is 20 mass% or less, More preferably It is 15 mass% or less, Most preferably, it is 10 mass% or less. The content of the radical polymerization initiator is preferable in terms of yield and economy.
The radical polymerization initiator will be described in detail later.

In the curable resin composition of the present invention, the content of the cationic polymerizable liquid compound having an aromatic structure (hereinafter, also simply referred to as “cationic polymerizable liquid compound”) is 100% by mass of the curable resin composition. The content of the cationic polymerizable liquid compound is preferably 10% by mass or more and 90% by mass or less. If it is 10% by mass or less, there is a possibility that the curable resin composition having a sufficiently low viscosity cannot be obtained. There exists a possibility that the refractive index of the hardened | cured material obtained from curable resin composition may become low as it is 90 mass% or more. The content of the cationically polymerizable liquid compound is more preferably 20% by mass or more, and further preferably 30% by mass or more. The curable resin composition of the present invention contains (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, a radical polymerization initiator, and a cationically polymerizable liquid compound having an aromatic structure as essential components. However, it is preferable that the total amount of these essential components is 50 to 100% by mass with respect to 100% by mass of the curable resin composition. More preferably, it is 60 mass% or more, More preferably, it is 80 mass% or more.

As described above, the curable resin composition of the present invention comprises (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, a radical polymerization initiator, and a cationically polymerizable liquid compound having an aromatic structure. Although it is essential, for example, it is a curable resin composition containing (meth) acrylate having the above conjugated structure and cured by a radical polymerization initiator, and the curable resin composition is cured at the time of curing. The same effects as those of the present invention can be obtained even with a curable resin composition containing a (meth) acrylate having a radical polymerization initiator and a cationically polymerizable liquid compound having an aromatic structure as essential components. That is, it is a curable resin composition containing a (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, and has a conjugated structure composed of 7 or more carbon atoms at the time of curing (meta A curable resin composition containing acrylate, a radical polymerization initiator, and a cationically polymerizable liquid compound as essential components is also one aspect of the present invention.

The curable resin composition contains a cationically polymerizable liquid compound having an aromatic structure as an essential component. When the curable resin composition contains the cationic polymerizable liquid compound, the viscosity of the curable resin composition can be reduced, and the curing shrinkage of the cured product can be reduced. As an optical member It becomes a more suitable curable resin composition. Moreover, the polymerization of (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms can be promoted by including a cationically polymerizable liquid compound. That is, the curing rate of the curable resin composition can be increased, and the productivity of the cured product can be improved. The cationic polymerizable liquid compound having the aromatic structure is a liquid compound having an aromatic structure and a reactive group for cationic polymerization, and does not have a conjugated structure composed of 7 or more carbon atoms. It is preferable.

It is preferable that the cationic polymerizable liquid compound having an aromatic structure essentially comprises a compound having an epoxy group and / or a compound having an oxetane group. According to this, since the viscosity can be further reduced and the high-speed curing can be achieved, the productivity can be greatly improved. The epoxy group is an organic group having an oxirane ring. A preferable form of the epoxy group is at least one form selected from the group consisting of a form in which the epoxy group is simple, a form in which the epoxy group is a glycidyl group, and a form in which the epoxy group is an alicyclic epoxy group. preferable.

Examples of the compound having an epoxy group, which is essential for the cationic polymerizable liquid compound having an aromatic structure, include an epi compound obtained by a condensation reaction of bisphenols such as bisphenol A, bisphenol F, bisphenol S, and fluorene bisphenol with an epihalohydrin. Bis-type glycidyl ether type epoxy resin; high molecular weight epibis type glycidyl obtained by further adding these epibis type glycidyl ether type epoxy resins with bisphenols such as bisphenol A, bisphenol F, bisphenol S, and fluorene bisphenol. Ether type epoxy resin; phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, bisphenol S, etc. Obtained by condensation reaction of aldehydes with formaldehyde, acetoaldehyde, propionaldehyde, benzaldehyde, hydroxybenzaldehyde, salicylaldehyde, dicyclopentadiene, terpene, coumarin, paraxylylene glycol dimethyl ether, dichloroparaxylylene, bishydroxymethylbiphenyl, etc. A novolak aralkyl type glycidyl ether type epoxy resin obtained by further condensation reaction of the polyhydric phenols obtained with an epihalohydrin is preferred. These can use 1 type (s) or 2 or more types.

As the compound having an epoxy group which is essential for the cationic polymerizable liquid compound having an aromatic structure, epoxy (meth) acrylate can also be suitably used. The epoxy (meth) acrylate is a (meth) acrylate obtained by reacting one or more epoxides with (meth) acrylic acid. Examples of the epoxide include (methyl) epichlorohydrin, bisphenol A, and bisphenol. S, bisphenol F, epichlorohydrin modified bisphenol type epoxy resin synthesized from ethylene oxide and propylene oxide modified products thereof; phenol novolac type epoxy resin; cresol novolac type epoxy resin; obtained by reacting with dicyclopentadiene and various phenols Epoxy products of various dicyclopentadiene-modified phenol resins; 2,2 ′, 6,6′-tetramethylbiphenol epoxides, aromatic epoxides such as phenyl glycidyl ether, etc. are suitable. is there. These can use 1 type (s) or 2 or more types.

Among the above-mentioned cationic polymerizable liquid compounds having an aromatic structure, bisphenol A type epoxy resin (bisphenol A), bisphenol F type epoxy resin (bisphenol F), aromatic epoxy resins having a bromo substituent, and the like are among the above. It is suitable and these 1 type (s) or 2 or more types can be used in combination. That is, as a cationically polymerizable liquid compound having an aromatic structure, the following general formulas (1-1) and (1-2):

(In the formula, ^{R 1,} .n ¹ the number of carbon atoms represents from 1 to 10 hydrocarbon group represents. A integer of 1 to 10) is represented by. More preferably, the following chemical formula (2):

Bisphenol A diglycidyl ether having the structure: As the bisphenol A diglycidyl ether, JER828EL (Japan Epoxy Resin, bisphenol A epoxy resin) is suitable.

When the cationic polymerizable liquid compound having an aromatic structure requires a compound having an oxetane group, the curing rate can be further improved as compared with the case where the compound having an oxetane group is not included. And the hardened | cured material which hardened the curable resin composition can be made excellent in surface smoothness and glossiness. Furthermore, the cationic polymerizable liquid compound having an aromatic structure is characterized in that it becomes a cured product excellent in toughness and elongation as compared with a case where a compound having an oxetane group is not essential.

As a compound having an oxetane group that is preferable for the cationic polymerizable liquid compound having an aromatic structure, for example, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl (for example, OXBP), 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene (for example, OXTP manufactured by Ube Industries, Ltd.), 3-ethyl-3- (2-phenoxymethyl) ) Oxetane, 1,4-bis {[(3-ethyl-3--3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3- (phenoxymethyl) oxetane (for example, OXT-211 manufactured by Toagosei Co., Ltd.), 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene (for example, OXT-121 manufactured by Toagosei Co., Ltd.) It is below. Among these, the following chemical formula (3):

(Wherein n ² represents an integer of 1 to 10), 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl represented by Ube Industries, Ltd. OXBP) is preferred.

The (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms in the present invention may have another organic group. The (meth) acrylate having the conjugated structure can be used alone or in combination of two or more.

In the (meth) acrylate having the conjugated structure, the conjugated unit constituting the conjugated structure is preferably a conjugated system (aromatic ring) having 7 or more carbon atoms, specifically, the following chemical formula (4) -1) to (4-8):

It is preferable that it has either of the structures represented by these. That is, a fluorene skeleton represented by the chemical formula (4-1) (a conjugated structure composed of 13 carbon atoms) and an anthracene ring represented by the chemical formula (4-2) (constructed by 14 carbon atoms) Conjugated structure), a dibenzothiophene ring represented by the chemical formula (4-3) (conjugated structure constituted by 12 carbon atoms), a carbazole represented by the chemical formula (4-4) (12 A conjugated structure composed of carbon atoms), a stilbene represented by the chemical formulas (4-5-1) and (4-5-2) (conjugated structure composed of 14 carbon atoms), and the chemical formula (4 -6) biphenyl (conjugated structure composed of 12 carbon atoms), naphthalene ring represented by the above chemical formula (4-7) (conjugated structure composed of 10 carbon atoms) Preferably it has one of the. Among these, when increasing the refractive index, those having fluorene, carbazole and the like in the skeleton structure, those having an anthracene ring, and a dibenzothiophene ring are more preferable. That is, it is one of preferred embodiments of the present invention that the conjugated structure requires at least one structure selected from the group consisting of a fluorene skeleton, an anthracene ring, a dibenzothiophene ring and a carbazole skeleton. Any conjugated structure may be used as long as it has the skeleton or ring structure described above. In addition, a structure in which bisphenol is bonded to the fluorene skeleton represented by the above chemical formula (4-8) (a conjugated structure composed of 25 carbon atoms) and the like are more preferable.
Note that having in the skeleton structure means that these structures may have a substituent within a range having a resonance structure.

In addition, specific examples of how to count the conjugated structures of the above-described compounds are as follows.
For example, in the fluorene structure represented by the following formula (a), 6-membered rings are connected even in the thick line portion. As a result, since the middle five-membered ring sandwiched between the aromatic rings also has a resonance structure, carbon surrounded by a dotted circle is also part of the conjugated structure, and there are 13 conjugated structures. Furthermore, when the fluorene structure and the benzene ring are directly bonded as in the structure represented by the following formula (b), the conjugated structure is further expanded, and the number of conjugated structures in the structure is 25.
On the other hand, in the case of a compound having a structure such as bisphenol A represented by the following formula (c), the central carbon is bonded to the aromatic ring as in the fluorene structure, but the central carbon itself. Is not a part of the ring structure and does not have a conjugated structure. In this case, one conjugated structure has 6 carbon atoms.

In the case of a linear compound, the number of carbon atoms constituting one conjugated structure is counted as 7 in both cases of the structures shown in the following formulas (d) and (e).

Among the above-described structures, the conjugated structure preferably has a fluorene skeleton structure as an essential component. When a compound having a fluorene skeleton structure as the conjugated structure is used, a cured product obtained by curing the curable resin composition of the present invention can have a refractive index of 1.60 or more. In addition, the compound in which the conjugated structure includes a fluorene skeleton structure not only has a high refractive index, but also exhibits various excellent properties such as heat resistance and high transparency in the visible light region. Since it can disperse | distribute uniformly, it can be used for various uses including optical uses, such as a high refractive index lens. Furthermore, when a compound containing a fluorene skeleton structure is used, the curable resin composition may increase in viscosity, but the curable resin composition contains a cationically polymerizable liquid compound having an aromatic structure. , Low viscosity can be achieved. Therefore, a curable resin composition having a high refractive index, a high curing rate, and excellent moldability can be obtained. Hereinafter, “a compound in which the conjugated structure includes a fluorene skeleton structure” is also simply referred to as “fluorene compound”.

Examples of the fluorene compound include the following general formulas (5-1) and (5-2):

(In formula, R < ² > is the same or different and represents a hydrogen atom or a methyl group, and R < ² > is the same or different and represents a hydrogen atom, a C1-C5 alkyl group, a phenyl group, or a halogen atom. n ³ is the same or different and is an integer of 0 to 10). More preferably, the following chemical formula (6):

Ogsol EA-0200 (Osaka Gas Chemical Co., Ltd., fluorene epoxy resin). Ogsol acrylates such as Ogsol EA-0200 are advantageous in that they have a basic structure of bisarylfluorene and have a high refractive index, low curing shrinkage, and high transparency.

When the said curable resin composition contains a fluorene compound, as content of the fluorene compound in curable resin composition, when the whole (meth) acrylate which has a conjugated structure shall be 100 mass%, it is 20 mass% (weight). %) Or more. More preferably, it is 25 mass% or more, More preferably, it is 30 mass% or more.

One of the preferred embodiments of the present invention is that the conjugated structure essentially requires a biphenyl skeleton structure. A compound having a conjugated structure including a biphenyl skeleton structure has an advantage that it has a high refractive index, is excellent in heat resistance, has high transparency in the visible light region, and can be used at low cost. Hereinafter, “a compound in which the conjugated structure includes a biphenyl skeleton structure” is also simply referred to as “biphenyl compound”.

As the biphenyl compound, the following general formula (7):

(Wherein R ³ is the same or different and represents a hydrogen atom or a methyl group. N ⁴ is the same or different and is an integer of 0 to 10). More preferably, the following chemical formula (8):

It is represented by

When the said curable resin composition contains a biphenyl compound, as content of the biphenyl compound in curable resin composition, when the whole (meth) acrylate which has a conjugated structure shall be 100 mass%, 30 mass% (weight) %) Or more. More preferably, it is 35 mass% or more, More preferably, it is 40 mass% or more.

The (meth) acrylate having the conjugated structure preferably has two or more acrylic groups in one molecule. By having two or more, there is an advantage that the mechanical strength of the cured product can be improved. More preferably, it is 2 to 3, more preferably 2.

The radical polymerization initiator is not particularly limited as long as it is a compound that generates radicals and initiates polymerization of the curable resin composition. Specifically, 2,2′-azobis- (2-methylbutyronitrile), 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2 .2′-azobis-2-methylpropionate methyl, 2,2′-azobisisobutyrate dimethyl, 2,2′azobis-2-methylvaleronitrile, 1,1′-azobis-1-cycloheptanenitrile, 1,1 Azo initiators such as' -azobis-1-phenylethane, phenylazotriphenylmethane; benzoyl peroxide, acetyl peroxide, tert-butyl peroxide, propionyl peroxide, lauroyl peroxide, tert-butyl peroxide, Tert-butyl perbenzoate, tert-butyl hydroperoxide, tert-butyl peroxypivalate, 1,1-bis (t-butyl) Peroxy) -3,3,5-trimethylcyclohexane, t- butyl peroxide initiators such as peroxy-2-ethylhexanoate; and the like. Of these, peroxide-based initiators are particularly preferred. Specifically, it is preferable to use perbutyl O (manufactured by NOF Corporation, radical generator).

The method for polymerizing the cationic polymerizable liquid compound having an aromatic structure is not particularly limited. Examples thereof include a method using a cationic polymerization initiator and a method using an acid anhydride curing agent. For example, when an acid anhydride curing agent is used, curing shrinkage can be reduced as compared with cationic polymerization, which is suitable for producing a thick film or a molded body. Examples of the acid anhydride curing agent include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, dodecynyl succinic anhydride, dichlorosuccinic anhydride, maleic anhydride, methyl nadic anhydride, Pyromellitic anhydride, methylhexahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, alkylstyrene-maleic anhydride copolymer Examples thereof include acid anhydrides such as coalescence, tetrabromophthalic anhydride, polyazeline acid anhydride, chlorendic acid anhydride, and benzophenone tetracarboxylic anhydride. Among these, those that are liquid at room temperature are preferable from the viewpoints of workability during production, characteristics after curing, productivity, and the like. The content of the cationic polymerization initiator in the curable resin composition of the present invention is preferably 0.001% by mass or more with respect to 100% by mass of the curable resin composition. More preferably, it is 0.05 mass% or more, More preferably, it is 0.01 mass% or more, Most preferably, it is 0.1 mass% or more. Moreover, it is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, and particularly preferably 10% by mass or less.

Among the methods of cationic polymerization of the cationic polymerizable liquid compound having an aromatic structure, a method using a cationic polymerization initiator is preferable. That is, it is preferable that the curable resin composition of the present invention further contains a cationic polymerization initiator as an essential component. According to this, the viscosity of the curable resin composition can be further reduced. The cationic polymerization initiator is not particularly limited as long as it can start cationic polymerization in the curable resin composition, but a photolatent curing catalyst and a thermal latent curing catalyst are suitable.
The heat latent curing catalyst is also called a heat latent curing agent or a heat latent cation generator, and exhibits a substantial function as a curing agent when a curing temperature is reached in the resin composition. Unlike the curing agent described later, the thermal latent curing catalyst does not cause an increase in viscosity or gelation with time of the curable resin composition at room temperature, even if it is contained in the curable resin composition, As an action of the heat latent curing catalyst, an excellent curing reaction accelerating effect can be exhibited, and therefore a one-component resin composition (one-component optical material) excellent in handling properties can be provided. In particular, when a curable resin composition is used as an optical material, it is preferable to use a thermal latent curing agent.

When the above-mentioned heat latent curing catalyst is used, the moisture resistance of the resulting resin composition is dramatically improved, and the excellent optical properties possessed by the curable resin composition are maintained even in harsh usage environments. The effect which becomes what can be used suitably for a use is acquired. Usually, if water having a high refractive index is contained in the curable resin composition or its cured product, it causes turbidity, but when a thermal latent curing catalyst is used, the resulting curable resin composition has excellent moisture resistance. Therefore, such turbidity is suppressed, and it can be suitably used for optical applications such as lenses. In particular, in applications such as on-vehicle cameras and bar code readers for home delivery companies, there are concerns about yellowing of lenses and deterioration of strength due to prolonged ultraviolet irradiation and high temperature exposure in summer. These phenomena are thought to be caused by the generation of oxygen radicals due to the synergistic effect of air and moisture with ultraviolet irradiation or heat ray exposure. However, the moisture resistance is improved, so that moisture absorption into the curable resin composition is prevented. Suppressed and also suppresses generation of oxygen radicals due to synergistic effects with ultraviolet irradiation or heat ray exposure, so that it can exhibit excellent heat resistance for a long time without causing yellowing or strength reduction of the curable resin composition. it can.

As the heat latent cation generator, the following average composition formula (1):
_{^{(R 4 a R 5 b R}} 6 c R 7 d Z) + m1 (AXn 5) -m1 (1)
(In the formula, Z represents at least one element selected from the group consisting of S, Se, Te, P, As, Sb, Bi, O, N and halogen elements. R ⁴ , R ⁵ , R ⁶ and R ⁷ is the same or different and represents an organic group, a, b, c and d are 0 or a positive number, and the sum of a, b, c and d is equal to the valence of Z. Cation (R ⁴ _a R ⁵ _b R ⁶ _c R ⁷ _d Z) ^{+ m1} represents an onium salt, A represents a metal element or a metalloid which is a central atom of a halide complex, B, P, As, Al, It is at least one selected from the group consisting of Ca, In, Ti, Zn, Sc, V, Cr, Mn, and Co. X represents a halogen element, and m1 is a net charge of a halide complex ion. .n ⁵ is a halogen source in the halide complex ion Of a number.) It is preferably represented by the.

The heat-latent cation generator is not particularly limited as long as it has the above-mentioned structure, but generally these generate cations at the curing temperature. The curing temperature is preferably 25 to 250 ° C. More preferably, it is 60-200 degreeC, More preferably, it is 80-180 degreeC.
Further, as a curing condition, the curing temperature may be changed stepwise. For example, after maintaining at a predetermined temperature and time in a mold for the purpose of improving productivity in producing a cured product from the curable resin composition, the mold is removed from the mold and left in an air or inert gas atmosphere. It is also possible to perform heat treatment. In this case, as the curing temperature, the holding temperature in the mold is 25 ° C to 250 ° C, more preferably 60 ° C to 200 ° C, still more preferably 80 ° C to 180 ° C, and the holding time is 10 seconds to 5 minutes, more preferably 30 ° C. Seconds to 5 minutes.

Specific examples of the anion (AXn ⁵ ) ^-m1 of the general formula (1) include tetrafluoroborate (BF ⁴⁻ ), hexafluorophosphate (PF ⁶⁻ ), hexafluoroantimonate (SbF ⁶⁻ ), hexa Examples thereof include fluoroarsenate (AsF ⁶⁻ ) and hexachloroantimonate (SbCl ⁶⁻ ).
Furthermore, an anion represented by the general formula AXn ⁵ (OH) ^— can also be used. Other anions include perchlorate ion (ClO ₄ ⁻ ), trifluoromethyl sulfite ion (CF ₃ SO ₃ ⁻ ), fluorosulfonate ion (FSO ₃ ⁻ ), toluenesulfonate ion, and trinitrobenzenesulfone. An acid ion etc. are mentioned.

As specific products of the above-mentioned heat latent cation generator,
Diazonium salt type: AMERICURE series (American Can), ULTRASET series (Adeka), WPAG series (Wako Pure Chemical Industries)
Iodonium salt type: UVE series (manufactured by General Electric), FC series (manufactured by 3M), UV9310C (manufactured by GE Toshiba Silicone), Photoinitiator 2074 (manufactured by Rhone-Poulenc), WPI series (manufactured by Wako Pure Chemical Industries)
Sulfonium salt type: CYRACURE series (manufactured by Union Carbide), UVI series (manufactured by General Electric), FC series (manufactured by 3M), CD series (manufactured by Satomer), optomer SP series, optomer CP series (Adeka) ), Sun Aid SI series (manufactured by Sanshin Chemical Industry Co., Ltd.), CI series (manufactured by Nippon Soda Co., Ltd.), WPAG series (manufactured by Wako Pure Chemical Industries, Ltd.), CPI series (manufactured by San Apro)
Etc. Among these, the sun aid SI series is preferable, and sun aid SI-60L, sun aid SI-80L, sun aid SI-100L (manufactured by Sanshin Chemical Industry Co., Ltd.) and the like can be suitably used.

Examples of the photolatent curing catalyst (also referred to as a photolatent cation generator or a photocationic polymerization initiator) include metal fluoroboron complex salts and trifluorinated boron complex compounds as described in US Pat. No. 3,379,653; Bis (perfluoroalkylsulfonyl) methane metal salts as described in US Pat. No. 3,586,616; aryldiazonium compounds as described in US Pat. No. 3,708,296; VIa as described in US Pat. No. 4,058,400 Aromatic onium salts of group elements; aromatic onium salts of group Va elements as described in US Pat. No. 4069055; dicarbonyl chelates of group IIIa to Va elements as described in US Pat. No. 4068091 A chain as described in US Pat. No. 4,139,655 Pyrylium salts; U.S. Pat MF as described in No. 4161478 ₆ ^- anion (where M is phosphorus, are selected from antimony and arsenic) VIb element in the form of; described in U.S. Patent No. 4,231,951 Arylsulfonium salts such as those described above; aromatic iodonium and aromatic sulfonium complex salts as described in US Pat. No. 4,256,828; R. Bis [4- (Di) as described by Watt et al. In "Journal of Polymer Science, Polymer Chemistry", Vol. 22, paragraph 1789 (1984). Ferrylsulfonio) phenyl] sulfide-bis-hexafluorometal salts (eg, phosphates, arsenates, antimonates, etc.); mixed ligand metal salts of iron compounds; silanol-aluminum complexes; . These compounds are also referred to as ultraviolet polymerization initiators. These ultraviolet polymerization initiators may be used alone or in combination of two or more.

Among the above ultraviolet polymerization initiators, arylsulfonium complex salts, aromatic iodonium complex salts of halogen-containing complex ions or aromatic sulfonium complex salts, and aromatic onium salts of group II, group V and group VI elements are preferred. Some of these include, for example, UVI-6992 (manufactured by Dow Chemical), FX-512 (manufactured by 3M), UVR-6990, UVR-6974 (manufactured by Union Carbide), and KI-85 (manufactured by Degussa). , SP-150, SP-170 (Asahi Denka Co., Ltd.) and other commercial products can be obtained.

The curable resin composition of the present invention may contain other organic components in addition to the (meth) acrylate having a conjugated structure as an essential organic resin and the above cationic polymerizable liquid compound having an aromatic group. .
It is preferable that content of another organic component is 0-30 mass% with respect to 100 mass% of curable resin compositions. More preferably, it is 0-10 mass%.
Hereinafter, other organic components will be described.

As said other organic component, the compound which has an oxetane group different from the cationically polymerizable liquid compound which has the said aromatic structure is mentioned. In general, the cation curability of an epoxy group-containing compound such as an epoxy resin has an early rise at the initial stage of curing but the subsequent curability is gentle, but the curability of the oxetane resin is relatively slow at the early stage of cure. Subsequent curability is fast. When these are used in combination, both the initial stage of curing and the subsequent curability are excellent, the curing characteristics required for the productivity of optical members and the like can be satisfied, and both curing characteristics and optical characteristics can be achieved. Therefore, when the curable resin composition includes a compound having an epoxy group, the curable resin composition preferably includes a compound having an oxetane group, in addition to the cationic polymerizable liquid compound having an aromatic structure.

Examples of the compound having an oxetane group include those in which the oxetane group is monofunctional and those in which the oxetane group is bifunctional.
Examples of the monofunctional oxetane group include 3-ethyl-3-hydroxymethyloxetane (for example, EHO manufactured by Ube Industries, Ltd.), 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (for example, Toago) Synthesizer Co., Ltd., OXT-212), 3-ethyl-3- (2-methacryloxymethyl) oxetane (for example, Ube Industries, Ltd., OXMA), 3-ethyl-3-{[3- (triethoxysilyl) propoxy ] Methyl} oxetane (for example, OXT-610, manufactured by Toagosei Co., Ltd.).
Examples of the bifunctional oxetane group include di [1-ethyl (3-oxetanyl)] methyl ether (for example, OXT-221 manufactured by Toagosei Co., Ltd.). Examples of the oxetane compound include silsesquioxane having an oxetane group such as oxetanylsilsesquioxane.

As the compound having an oxetane group, the compound having a monofunctional oxetane group is represented by the following general formula (9):

(In formula, R < ⁸ > is the same or different and represents a C1-C10 hydrocarbon group, a C1-C10 alkoxy group, or a C1-C10 hydroxyalkylene group.) The thing represented by these is preferable. The number of carbon atoms of R ⁸ is more preferably 1 to 4, still more preferably 1 or 2, and particularly preferably 1. Specifically, the oxetane group is monofunctional as shown in the following formula (10):

3-ethyl-3-hydroxymethyloxetane represented by the following formula (11):

3-ethyl-3- (2-ethylhexyloxymethyl) oxetane represented by Examples of the bifunctional oxetane group include the following general formula (12):

(In formula, R < ⁹ > is the same or different and represents a C1-C10 hydrocarbon group, a C1-C10 alkoxy group, or a C1-C10 hydroxyalkylene group. R ¹⁰ represents a divalent organic group having 1 to 30 carbon atoms, and n ⁶ is an integer of 1 to 20).
The number of carbon atoms of R ^9, more preferably from 1 to 4, more preferably 1 or 2, particularly preferably 1.

Specific examples of the compound represented by the general formula (9) or (12) include 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] And methyl ether. Of these, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, and the like are preferable. More preferred is 3-ethyl-3-hydroxymethyloxetane represented by the above chemical formula (10).

The compound having an oxetane group preferably has a monofunctional oxetane group. This is because the oxetane monomer having two or more polymerizable groups increases the resin viscosity and leads to a decrease in workability when it is bifunctional or higher. Therefore, the curing rate can be further increased by the monofunctional oxetane group.

The compound having an oxetane group preferably has a hydroxyl group. Generally, when an oxetane compound having a hydroxyl group is contained in the curable resin composition, the rate of cationic polymerization is reduced. However, in the case of a curable resin composition having the configuration of the present invention, the polymerization rate can be improved. Since the compound having an oxetane group has a low refractive index, in order to obtain a cured product having a high refractive index, it is preferable to reduce the addition amount as much as possible, but it is essential that the compound having an oxetane group has a hydroxyl group. Then, since the curing rate of the resin can be sufficiently increased even if the addition amount is reduced, a cured product having a higher refractive index can be produced by reducing the addition amount of the compound having an oxetane group. One or two or more oxetane compounds having a hydroxyl group can be used.

As a preferable form of the oxetane compound having a hydroxyl group, in the general formula (9), at least one of R ⁸ is a hydroxyalkylene group, and in the general formula (12), at least one of R ⁹ is a hydroxyalkylene group. It is a form that is. More preferred is 3-ethyl-3-hydroxymethyloxetane represented by the above chemical formula (10). That is, it is one of the preferable embodiments of the present invention that the other oxetane compound essentially requires 3-ethyl-3-hydroxymethyloxetane. When the oxetane compound having a hydroxyl group is 3-ethyl-3-hydroxymethyloxetane, the amount of the other oxetane group-containing compound can be sufficiently reduced, so that a cured product having a higher refractive index can be obtained. it can.

Examples of other organic components other than the compound having an oxetane group include, for example, a curable resin, a thermoplastic resin, a polyhydric phenol compound, a compound having a polymerizable unsaturated bond, and an epoxy group described later. A curable compound such as a compound having one is preferable. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, acrylonitrile / styrene copolymer (AS resin), ABS resin made of acrylonitrile / butadiene / styrene, vinyl chloride resin, (meth) acrylic resin, polyamide resin, and acetal resin. , Polycarbonate resin, polyphenylene oxide, polyester, polyimide and the like.

The other organic component is preferably an epoxy group-containing compound, that is, a compound having at least one epoxy group other than the cationic polymerizable compound having the conjugated structure described above from the viewpoint of curing speed. By having at least one epoxy group, it has the effect of further improving the curing rate, and has heat resistance comparable to that of inorganic glass while having workability equivalent to that of thermosetting plastic materials, and is excellent in molding and workability. Such excellent characteristics can be exhibited. Hereinafter, the compound which has at least one epoxy group which can be used suitably for the curable resin composition of this invention is demonstrated.

As the compound having at least one epoxy group, the following compounds are suitable. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, PEG600, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, PPG, glycerol, diglycerol, tetraglycerol, polyglycerol, trimethylolpropane and the like An aliphatic glycidyl ether type epoxy resin (aliphatic glycidyl ether type epoxy compound) obtained by a condensation reaction of a monomer / polysaccharide such as multimers, pentaerythritol and its multimers, glucose, fructose, lactose, maltose and the like and an epihalohydrin; (3,4-epoxycyclohexane) epoxycyclohexyl such as methyl 3 ', 4'-epoxycyclohexylcarboxylate An epoxy resin having a sun skeleton (an epoxy compound having an epoxy cyclohexane skeleton); a tertiary amine-containing glycidyl ether-type epoxy resin solid at room temperature obtained by a condensation reaction of hydantoin, cyanuric acid, melamine, benzoguanamine and epihalohydrin is exemplified . Among them, the aliphatic glycidyl ether type epoxy resin and the epoxy resin having an epoxycyclohexane skeleton are more preferably used for the purpose of suppressing the appearance deterioration during light irradiation.

As the compound having at least one epoxy group, epoxy (meth) acrylate having no aromatic group can also be suitably used.
The epoxy (meth) acrylate is a (meth) acrylate obtained by reacting one or more epoxides with (meth) acrylic acid. Examples of the epoxide include (methyl) epichlorohydrin and hydrogenated bisphenol A. , Hydrogenated bisphenol S, hydrogenated bisphenol F, epichlorohydrin modified hydrogenated bisphenol type epoxy resin synthesized from ethylene oxide, propylene oxide modified products thereof; 3,4-epoxycyclohexylmethyl, bis- (3,4-epoxycyclohexyl) ) Cycloaliphatic epoxy resin such as adipate; Cycloaliphatic epoxide such as epoxy resin containing heterocycle such as triglycidyl isocyanurate; (poly) ethylene glycol, (poly) propylene glycol, (poly) butylene glycol, (poly) (Poly) glycidyl ethers of glycols such as tramethylene glycol and neopentyl glycol; (Poly) glycidyl ethers of alkylene oxide modified products of glycols; trimethylolpropane, trimethylolethane, glycerin, diglycerin, erythritol, pentaerythritol, (Poly) glycidyl ethers of aliphatic polyhydric alcohols such as sorbitol, 1,4-butanediol, 1,6-hexanediol; alkylene type epoxides such as (poly) glycidyl ether of an alkylene oxide-modified product of aliphatic polyhydric alcohols Glycidyl ester of carboxylic acid such as adipic acid, sebacic acid, maleic acid, itaconic acid, glycidyl ether of polyester polyol of polyhydric alcohol and polycarboxylic acid; glycidyl (meta Acrylates, copolymers of methyl glycidyl (meth) acrylate; glycidyl esters of higher fatty acids, epoxidized linseed oil, epoxidized soybean oil, epoxidized castor oil, aliphatic epoxy resins such as epoxidized polybutadiene and the like.

The other organic component may contain a solvent, and the amount of the solvent contained in the organic component is preferably 20% by mass or less with respect to 100% by mass of the curable resin composition. When it exceeds 20 mass%, when an organic resin component (organic component which is resin) is included, there exists a possibility that a bubble may arise in a molded object. More preferably, it is 10 mass% or less as a solvent amount, More preferably, it is 5 mass% or less, Especially preferably, it is 3 mass% or less, Most preferably, it is 1 mass% or less.

If the said curable resin composition contains the (meth) acrylate which has a conjugated structure which consists of 7 or more carbon atoms, the cation polymerizable liquid compound which has an aromatic structure, and a radical polymerization initiator, especially Although it is not limited, it can be set as a more suitable aspect by containing an inorganic component. Below, the inorganic component suitable for being contained in the curable resin composition will be described. In the present invention, the inorganic component includes an organic compound containing an inorganic element as a constituent element of the compound, such as an organosiloxane compound described later.
The content of the inorganic component may be appropriately selected depending on the type of inorganic component and the blending purpose, but is usually in the range of 0.01 to 50% by mass, preferably 0, with respect to 100% by mass of the curable resin composition. It is selected within the range of 1 to 20% by mass.

The curable resin composition preferably contains an organosiloxane compound as an inorganic component. Thereby, the heat resistance of the hardened | cured material after hardening a curable resin composition can be improved. By improving the heat resistance, it can be more suitably used as on-vehicle needs such as a lens for an in-vehicle camera and a lens for a bar code reader for a courier that require heat resistance.

The organosiloxane compound has a siloxane skeleton. As such a siloxane skeleton, any siloxane bond may be used, and the structure of the siloxane skeleton may be either linear or branched, ladder shape, cage shape, cubic shape. A polysilsesquioxane having a structure such as the above is preferable. In the organosiloxane compound, the proportion of the siloxane skeleton is preferably 80 to 10% by mass in 100% by mass of the organosiloxane compound. More preferably, it is 70-15 mass%, More preferably, it is 50-20 mass%.

The curable resin composition has the following average composition formula (2):
R ¹¹ _e R ¹² _f Y _g SiO _h (2)
(Wherein R ¹¹ represents a saturated aliphatic hydrocarbon group. R ¹² represents at least one selected from the group consisting of an aryl group and an aralkyl group. Y represents an RO group, a hydroxyl group, a halogen atom and hydrogen. Represents at least one selected from the group consisting of atoms, e, f, g and h are 0 <e <3, 0 ≦ f <3, 0 ≦ g <3, 0 <e + f + g <3, 0 <e + f < 3 and e + f + g + 2h = 4) is preferably included. When the curable resin composition contains an organosiloxane compound, the curing shrinkage rate is small, the film thickness can be increased, and it can be suitably used for various applications. In particular, when used as an optical waveguide, it has excellent adhesion between the clad and the core, and can satisfy necessary physical properties such as reducing optical loss. Moreover, the said curable resin composition is easy to shape | mold, it is excellent in heat-curing property, workability | operativity, such as handling, and it is excellent in storage stability. In addition, the molded article exhibits excellent optical properties such as transparency (optical homogeneity), good heat resistance, and excellent mechanical properties such as bending strength. Furthermore, since the organosiloxane compound has R ¹¹ and / or R ¹² which are inactive (low reactivity) organic groups, the curable resin composition of the present invention can be stored over time even when stored for a long period of time. The increase in typical viscosity is small, and even when a curing agent or a curing catalyst is added, the gelation reaction hardly proceeds at room temperature.

Since the organosiloxane compound has R ¹¹ and / or R ¹² which are inert and low-reactive organic groups, it is characterized by a small increase in viscosity over time of the curable resin composition. An organosiloxane compound having such an inert organic group is particularly preferable in that it has no effect of promoting thickening while improving heat resistance and mechanical properties.

As said organosiloxane compound, when raising the refractive index of the said curable resin composition, it is preferable to have an aromatic ring. The structure of the compound may be either linear or branched, and is preferably a polysilsesquioxane having a ladder or cage structure. Specifically, silicone oligomer PPSQ-E (manufactured by Konishi Chemical Industries, PPSQ-E, number average molecular weight 850), silicone oligomer PPSQ-H (manufactured by Konishi Chemical Industries, PPSQ-H, number average molecular weight 2200), and the like. preferable. Silicone oligomer PPSQ-E is a powdered polyorganosiloxane having a benzene ring in its structure, and is in the form of a string, so that it does not aggregate in the solution and is easily dispersed.
When the organosiloxane compound does not have a cationic polymerizable group, the amount of aromatic ring in the organosiloxane compound having no cationic polymerizable group is 40% by mass or more with respect to 100% by mass of silicon atom. Is preferred. If the amount of the aromatic ring in the organosiloxane compound having no cationically polymerizable group is less than 40% by mass, the refractive index may be sufficiently high and cannot be suitably used for optical applications. The amount of the aromatic ring is more preferably 50% by mass or more, still more preferably 100% by mass or more, and particularly preferably 200% by mass or more.

When the organosiloxane has a cationic polymerizable group, it is possible to suppress a delay in the curing rate of the (meth) acrylate having the conjugated structure. In particular, the initial speed, which is important when producing a minute material such as an optical lens in a short time, can be sufficiently increased, and an optical material can be suitably produced. When the organosiloxane compound has a structure in which an electron-donating alkyl group is connected to a glycidyl ether group, the stability of the cation on the epoxy group is improved and the cation curing rate is high. The influence of the delay in the curing speed due to the resin being contained can be minimized, and the productivity can be improved. Moreover, it can be set as the curable resin composition excellent in transparency by entering the said network. Furthermore, since the crosslink density is increased, the heat resistance is increased due to an increase in the glass transition temperature.

The curable resin composition preferably contains a high refractive index component as an inorganic component. According to this, it becomes possible to form a cured product having a higher refractive index. The high refractive index component is preferably metal oxide particles having a refractive index of 2 or more, such as metal oxide particles such as titania, zirconia, yttria, lanthanum oxide, indium oxide, zinc oxide, and tin oxide. When such a high refractive index component is contained, it is particularly preferable when used as an optical member of a device requiring a high refractive index such as a camera or an antireflection film.

As said metal oxide particle, it is preferable that the average particle diameter of a primary particle is 100 nm or less. More preferably, it is 20 nm or less, More preferably, it is 15 nm or less. By setting it as such a range, curable resin composition and hardened | cured material with high transparency and light transmittance can be obtained.
The primary particle diameter is a number average particle diameter obtained from a TEM image (observation with a transmission electron microscope); specific surface area diameter (weight average particle diameter obtained by measurement of BET surface area; powder X-ray diffraction measurement method) The average particle diameter obtained from the radius of inertia obtained by the X-ray small angle scattering method and the scattering intensity, etc. Among these, the number average particle diameter obtained from the TEM image is preferable.
The shape of the metal oxide particles is not limited to a spherical shape, and may be, for example, a thin piece such as an elliptical sphere, a cube, a rectangular parallelepiped, a pyramid, a needle, a column, a rod, a cylinder, a flake, and a (hexagon) plate A shape, a string shape or the like is preferable.
As content of the said metal oxide particle, it is preferable that it is 10-80 mass% in 100 mass% of curable resin compositions. More preferably, it is 20-50 mass%. By setting it as such content, both high refractive index and improvement of workability | operativity can be aimed at.

The curable resin composition of the present invention preferably contains wet inorganic fine particles as an inorganic component. The wet inorganic fine particles are inorganic fine particles synthesized by a liquid phase reaction. Specific examples of the wet inorganic fine particles include inorganic fine particles synthesized by a sol-gel method. Among these, inorganic fine particles synthesized by a hydrothermal method are preferable.
The content of wet inorganic fine particles in 100% by mass of the inorganic component is preferably 10 to 100% by mass. More preferably, it is 50-100 mass%, More preferably, it is 80-100 mass%.

In the curable resin composition of the present invention, when the refractive index is increased, it is preferable to use the high refractive index nanoparticles, titanoxane compound, or the like as the inorganic component. When increasing the refractive index, high refractive index nanoparticles are more preferable, and TiO ₂ is more preferable than the titanoxane compound. In addition, a titanoxane compound etc. can be mix | blended in high concentration.

When the curable resin composition of the present invention contains inorganic components such as the organosiloxane compound and the metal oxide particles, the coefficient of thermal expansion can be reduced and the mold release effect can be improved. Thereby, productivity of hardened | cured material can be improved further.

The curable resin composition preferably includes a flexible component (flexible component). By including a flexible component, a resin composition having a sense of unity can be obtained. As said flexible component, (1) the form which is a flexible component which consists of a compound different from an organic resin component (organic component which is resin), (2) 1 type of an organic resin component is a flexible component. Any of certain forms can be suitably applied. Specifically, a compound having an oxyalkylene skeleton represented by — [— (CH ₂ ) _n ⁷ —O—] _m2 − (n ⁷ is an integer of 2 or more, m2 is an integer of 1 or more. Preferably, n ⁷ 2-12, the m2 more preferably an integer of 1 to 1000., ^{n 7} is 3 to 6, m2 is an integer of from 1 to 20.) are preferable, compounds further having an epoxy group is preferable. Among them, a compound having an oxybutylene skeleton and an epoxy group is preferable, and examples of industrial products include YL-7217 (epoxy equivalent 437, liquid epoxy resin) manufactured by Japan Epoxy Resin Co., Ltd.
In addition, examples of other preferable compounds as the flexible component include hydrogenated epoxy compounds such as YL-7170 (epoxy equivalent 1000, hydrogenated bisphenol type epoxy resin) manufactured by Japan Epoxy Resin; JER1007 manufactured by Japan Epoxy Resin Aromatic epoxy compounds such as (epoxy equivalent 1750-2200, bisphenol A type epoxy resin); high molecular weight alicyclic solid epoxy resin such as EHPE-3150 (solid at normal temperature) manufactured by Daicel Chemical Industries; manufactured by Daicel Chemical Industries, Ltd. An epoxy compound such as an epoxy resin having an alkylene skeleton composed of 4 or more carbon atoms such as Celoxide 2081 (liquid at normal temperature) is exemplified.
YL-7170 manufactured by Japan Epoxy Resin Co., Ltd. and JER1007 manufactured by Japan Epoxy Resin Co. may be preferably used from the viewpoint of high molecular weight.
In addition, liquid rubber such as liquid nitrile rubber, polymer rubber such as polybutadiene, and fine particle rubber having a particle size of 100 nm or less are also preferable.
High molecular weight alicyclic solid epoxy resin; liquid rubber such as liquid nitrile rubber, polymer rubber such as polybutadiene, fine particle rubber having a particle size of 100 nm or less, and the like are preferable. The flexible component can be appropriately contained for the purpose of improving mechanical strength characteristics as long as the effects of the present invention are not impaired, but the content is not particularly limited and may be appropriately selected. Usually, it selects from the range of 0.01-50 mass% with respect to 100 mass% of curable resin compositions, Preferably, it selects from the range of 0.1-20 mass%.

As described above, the curable resin composition of the present invention preferably includes an organic component and an organosiloxane compound, and further includes a flexible component. That is, a form comprising a flexible material (flexible component), a fluorene compound having a cationic polymerizable group (more preferably, a fluorene epoxy resin) and an organosiloxane compound is also a preferred form of the present invention. One.
The viscosity of the curable resin composition is particularly preferably 10,000 Pa · s or less, more preferably 1000 Pa · s or less, and most preferably 200 Pa · s or less.

In addition to other organic components, organosiloxane compounds, inorganic components such as metal oxide particles and flexible components, the curable resin composition of the present invention includes a mold release agent, a curing agent, a curing accelerator, and a reactive dilution. Agents, saturated compounds without unsaturated bonds, pigments, dyes, antioxidants, UV absorbers, light stabilizers, plasticizers, non-reactive compounds, chain transfer agents, polymerization inhibitors and organic fillers, couplings Adhesion improvers such as agents, heat stabilizers, antibacterial and antifungal agents, flame retardants, matting agents, antifoaming agents, leveling agents, wetting / dispersing agents, antisettling agents, thickeners / sagging agents, colors An anti-separation agent, an emulsifier, an anti-slip / scratch agent, an anti-skinning agent, a drying agent, an antifouling agent, an antistatic agent, a conductive agent (electrostatic aid), and the like may be contained.

As the mold release agent, a normal mold release agent can be suitably used, but it is at least one compound selected from the group consisting of alcohols having 8 to 36 carbon atoms, carboxylic acids, carboxylic acid esters, and carboxylate salts. Preferably there is. By containing such a release agent, when cured using a mold, the mold can be easily peeled off, the appearance is controlled without damaging the surface of the cured product, and transparency is improved. Since it can be expressed, it is particularly useful as a material for electrical / electronic component materials and optical applications.

The compound used as the mold release agent may be any compound having at least one compound selected from the group described above, and among these, alcohols, carboxylic acids, and carboxylic acid esters are preferable. Acids (especially higher fatty acids). In addition, this compound may have any structure such as linear, branched, and cyclic structures, and is preferably branched.
The number of carbon atoms of this compound is preferably an integer of 8 to 36. If it has a certain amount of long chain in such a range, it exhibits the effect of the present invention, and exhibits excellent releasability without impairing functions such as transparency and workability of the curable resin composition Can do. In addition, it is relatively easy to obtain and can be economical. More preferably, it is 8-20 as carbon number, More preferably, it is 10-18.

The compound used as the mold release agent is preferably at least one compound selected from the group consisting of alcohols having 8 to 36 carbon atoms, carboxylic acids, carboxylic acid esters, and carboxylates. Specific examples of these are as follows.
The alcohol having 8 to 36 carbon atoms is a monovalent or polyhydric alcohol, and may be linear or branched. Specifically, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, palmityl alcohol, margaryl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl Alcohol, seryl alcohol, myricyl alcohol, methylpentyl alcohol, 2-ethylbutyl alcohol, 2-ethylhexyl alcohol, 3.5-dimethyl-1-hexanol, 2,2,4-trimethyl-1-pentanol, dipentaerythritol 2-phenylethanol and the like are preferred. Among these, aliphatic alcohols are preferable, and octyl alcohol (octanol), lauryl alcohol, 2-ethylhexyl alcohol (2-ethylhexanol), and stearyl alcohol are more preferable.

The carboxylic acid having 8 to 36 carbon atoms is a monovalent or polyvalent carboxylic acid, and includes 2-ethylhexanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, and tetradecanoic acid. Pentadecanoic acid, palmitic acid, 1-heptadecanoic acid, stearic acid, nonadecanoic acid, eicosanoic acid, 1-hexacosanoic acid, behenic acid and the like are suitable. Among these, octanoic acid, lauric acid, 2-ethylhexanoic acid, and stearic acid are preferable.

The carboxylic acid ester having 8 to 36 carbon atoms is (1) carboxylic acid ester obtained from the above alcohol and carboxylic acid, and (2) carbon such as methanol, ethanol, propanol, heptanol, hexanol, glycerin, benzyl alcohol, etc. Carboxylic acid ester obtained by the combination of the number 1-7 alcohol and the above carboxylic acid, (3) a combination of the above alcohol with a carboxylic acid having 1 to 7 carbon atoms such as acetic acid, propionic acid, hexanoic acid, butanoic acid, etc. The resulting carboxylic acid ester is preferred. Among these, stearic acid methyl ester, stearic acid ethyl ester, octyl acetate and the like are preferable.

The carboxylate having 8 to 36 carbon atoms is a carboxylic acid obtained by a combination of the carboxylic acid and an amine, Na, K, Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, or Sn. Salts and the like are preferred. Among these, Zn stearate, Mg stearate, Zn 2-ethylhexanoate and the like are preferable.

The compound used as the mold release agent is more preferably a stearic acid compound such as stearic acid and a stearic acid ester, or an alcohol compound, and more preferably a stearic acid compound. Thus, the curable resin composition containing a stearic acid type compound is also one of the preferable forms of this invention.

As content of the said mold release agent, it is preferable that it is 10 mass% or less with respect to 100 mass% of curable resin compositions. If it exceeds 10% by mass, the resin may be difficult to cure. More preferably, it is 0.01-5 mass%, More preferably, it is 0.1-2 mass%.

The present invention is also a cured product obtained by curing the curable resin composition of the present invention. The cured product obtained by curing the curable resin composition of the present invention is excellent in various optical properties.
The turbidity (haze) of the cured product is preferably 20% or less. The turbidity of the cured product is more preferably 10% or less, still more preferably 5% or less, and particularly preferably 1% or less. Moreover, as transparency of hardened | cured material, it is preferable that the light transmittance of visible region (region whose wavelength is 360-780 nm) is 75% or more. The light transmittance of the cured product is more preferably 80% or more, still more preferably 85% or more, and particularly preferably 87% or more.
In the above cured product, a wide range of numerical values are required for the refractive index and Abbe number of the cured product depending on the optical design of the applied optical system. The light transmittance of the cured product can be measured by a method according to JIS K7361-1, the turbidity can be measured by JIS K7136, and the refractive index / Abbe number can be measured by a method according to JIS K7142.
The PCT moisture absorption of the cured product varies depending on the curing conditions, but by optimizing the curing conditions, it is preferably 2% or less, preferably 1% or less, more preferably 0.5% or less. More preferably, it is 0.2% or less.

The cured product preferably has a refractive index of 1.60 or more. More preferably, it is 1.61 or more. By making the said hardened | cured material of a high refractive index, it can use suitably for various uses. In particular, it is useful when used for optical applications. In addition, it is preferable that the hardened | cured material of this invention is a thing obtained by hardening a curable resin composition with the hardening method mentioned later.
The refractive index is obtained by measuring the refractive index of 589 nm at 20 ° C. using a refractometer (DR-M2 manufactured by Atago Co., Ltd.). The cured product when measuring the refractive index is preferably in the form of a film having a thickness of 250 μm.

The cured product preferably has high heat resistance, that is, has no change in appearance such as generation of cracks even at high temperatures, and has a low rate of change in total light transmittance and turbidity. Specifically, when the temperature of the cured product is increased from 25 ° C. to 260 ° C., there is no change in appearance such as cracking, and the change rate of total light transmittance / turbidity is 20% or less. Is preferred. More preferably, the total light transmittance and the change rate of turbidity are 15% or less, and more preferably 10% or less. Moreover, it is preferable that the change of the total light transmittance and turbidity after leaving for 500 hours in an atmosphere of temperature 85 degreeC and humidity 85% is 20% or less. More preferably, it is 15% or less.
Especially in applications such as in-vehicle cameras and bar code readers for home delivery companies, there are concerns about yellowing and deterioration of strength due to prolonged UV irradiation and high temperature exposure in summer. The cause is considered to be the generation of oxygen radicals due to a synergistic effect with exposure to heat rays. Improved moisture resistance suppresses moisture absorption in the cured product and suppresses generation of oxygen radicals due to a synergistic effect with ultraviolet irradiation or heat ray exposure, so that the cured product will not turn yellow or lose strength for a long time. Excellent heat resistance can be exhibited.

This invention is also an optical member comprised including the hardened | cured material which hardens the said curable resin composition. The optical member is a curable material using the curable resin composition. The curable resin composition of the present invention exhibits excellent transparency and optical characteristics as described above, and a cured product obtained by curing the curable resin composition also exhibits similar characteristics. It can be suitably used for various applications such as applications, optical device applications, and display device applications.
The optical member of the present invention preferably comprises a cured product obtained by curing the curable resin composition with heat or light. In addition, although the optical member contains the said curable resin composition, it may contain the other component suitably according to the use of the optical member. Specifically, UV absorber, IR cut agent, reactive diluent, pigment, washing agent, antioxidant, light stabilizer, plasticizer, non-reactive compound, chain transfer agent, thermal polymerization initiator, anaerobic polymerization Initiators, light stabilizers, polymerization inhibitors, antifoaming agents and the like are suitable.

As a form of the optical member, the transmittance at a wavelength of 500 nm is preferably 60% or more. When the transmittance is in such a range, an optical material having high transparency and excellent optical characteristics is obtained. The transmittance of the optical material is more preferably 80% or more, and still more preferably 85% or more. If the transmittance at a wavelength of 500 nm is less than 60%, the transmittance is insufficient for lens applications.

Specifically, the optical member is preferably used as an imaging lens for an in-vehicle camera, a PC camera, a digital camera, a mobile phone, a digital video, a surveillance camera, a PDA, a PC built-in camera, or the like. Thus, a lens using the optical member of the present invention is also one of the preferred embodiments of the present invention. Optical applications such as eyeglass lenses, filters, diffraction gratings, prisms, light guides, light beam condensing lenses and light diffusing lenses, transparent glasses such as watch glasses and cover glasses for display devices, and cover glasses; photo sensors , Photoswitches, LEDs, light emitting elements, optical waveguides, multiplexers, duplexers, disconnectors, optical splitters, optical device adhesives, etc .; LCD, organic EL, PDP display element substrates, It can also be suitably used as an optical member for display device applications such as a color filter substrate, a touch panel substrate, a display protective film, a display backlight, a light guide plate, an antireflection film, and an antifogging film.

The present invention is also an optical unit including the optical member. As described above, since the optical member of the present invention exhibits excellent transparency and optical characteristics, the optical unit including such an optical member also exhibits excellent performance. Become. Examples of the optical unit include a lens unit. Since the optical member of the present invention includes a cured product having a high refractive index, the use of this optical member can reduce the thickness of the lens and reduce the weight of the lens unit. Thus, a lens unit using the cured product is also one aspect of the present invention. Hereinafter, preferred embodiments of the lens and lens unit using the cured product of the present invention will be described in detail.

The lens using the optical member of the present invention preferably has a thickness of less than 1 mm. By setting the thickness of the lens (the maximum thickness of the region where the image is captured) to less than 1 mm, the optical path length can be shortened and the lens unit can be made smaller. The thickness of the lens is more preferably less than 800 μm, and still more preferably less than 500 μm.

In the lens unit, the number of lenses may be one, or two or more. In the case of a single lens, the Abbe number of the lens is preferably 45 or more. When there are two or more lenses, it is sufficient that the Abbe number of at least one lens is 45 or more, and the other lenses may have an Abbe number of less than 45. In the case of combining a lens having an Abbe number of 45 or more and a lens having an Abbe number of less than 45, it is more preferable to combine a lens having an Abbe number of 50 or more and a lens having an Abbe number of 40 or less. By combining a lens having an Abbe number of 50 or more and a lens having an Abbe number of 40 or less, there is an advantage that the resolution is improved and the characteristics required for the lens unit are satisfied. The lens using the optical member of the present invention is suitable as a lens having an Abbe number of 40 or less.

Examples of the lens unit include a form including the lens. The lens preferably has a thickness of less than 1 mm and has at least one lens having an Abbe number of 50 or more. The thickness of the lens unit is preferably 50 mm or less. By setting it as such thickness, it can use suitably for various optical members, such as a camera module. More preferably, it is 30 mm or less as a thickness of a lens unit, More preferably, it is 10 mm or less.

Hereinafter, a preferred method for producing a curable resin composition containing (meth) acrylate having a conjugated structure, an organic component having a cationic polymerizable liquid compound having an aromatic structure as an essential component, and a radical polymerization initiator as an essential component will be described. To do.
The production method of the curable resin composition of the present invention is not particularly limited as long as the effects of the present invention can be exhibited. For example, the (meth) acrylate having the conjugated structure, the cationic polymerizable liquid compound having an aromatic structure. In the case where it is difficult to uniformly mix components constituting the curable resin composition such as a radical polymerization initiator, (1) a step of preparing a mixture containing the components constituting the curable resin composition and a solvent; And (2) a degassing step of degassing the solvent from the mixture.

The preparation step of (1) is not particularly limited as long as the above mixture can be prepared, as long as the components constituting the curable resin composition are uniformly mixed, and any addition (blending) order and mixing method can be used. Can be used. Furthermore, the said mixture may contain the other component.
As a preparation process, it is preferable to adjust the degree of vacuum and perform the preparation at 100 ° C. or lower.
In the preparation step, the ratio of the resin component and the solvent is preferably (component constituting the curable resin composition) / (component constituting the curable resin composition + solvent) = 10 to 90% by mass. . More preferably, it is 15-60 mass%. Specifically, methanol, ethanol, isopropanol, butanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, acetonitrile, chloroform, toluene, xylene and the like are preferable as the solvent. More preferred are isopropanol, butanol, methyl ethyl ketone, and toluene.

The degassing step (2) is preferably performed in the presence of a high-boiling component. By deaeration in the presence of a high-boiling component, thickening of the mixture can be effectively suppressed, and continuous production becomes possible. The term “in the presence of a high-boiling component” only requires a period during which the high-boiling component coexists in the deaeration process, and the coexistence period is a partial period even during the entire period of the deaeration process. However, the entire period is preferable to prevent thickening.
The method for adding the high boiling point component is not particularly limited as long as the effects of the present invention are exhibited, and may be added all at once, may be added dropwise, or may be divided additions. Among these, batch addition is preferable. Moreover, it does not specifically limit as addition time (or addition start time) of a high boiling component, For example, (1) It is after completion | finish of a preparation process, and before the start of a deaeration process, (2) It may be in the preparation process or (3) in the degassing process. Among these, (1) is preferable for preventing thickening. Thus, the manufacturing method which adds a high boiling point component before deaerating the solvent after mixing the component which comprises curable resin composition is also one of the preferable forms of this invention.

The amount of the high-boiling component added is 0.01 to 10% by mass with respect to 100% by mass of the mixture of the organic component, the solvent before degassing, the high-boiling component and other components such as inorganic components as necessary. Preferably there is. More preferably, it is 0.1-5 mass%, More preferably, it is 0.5-3 mass%.
Note that the high boiling point component remains in the composition at the end of the degassing step. The proportion is preferably 0.01 to 10% by mass in 100% by mass of the mixture at the end of the degassing step. More preferably, it is 0.01-5 mass%, More preferably, it is 0.5-3 mass%.
The residual amount of the high-boiling component can be measured by gas chromatography (GC). The measurement conditions are as follows.
(GC measurement conditions)
Column: “DB-17” manufactured by GL Sciences Inc.
Carrier gas: Helium flow rate: 1.44 mL / min

In the degassing step, the conditions are not particularly limited as long as the solvent can be degassed. However, when organic components are decomposed or cured, and inorganic components are used, the inorganic components are prevented from aggregating excessively. It is preferable that Specifically, the deaeration temperature is preferably 200 ° C. or less. More preferably, it is 100 degrees C or less, More preferably, it is 80 degrees C or less. The deaeration time is preferably 72 hours or less. More preferably, it is 24 hours or less, More preferably, it is 2 hours or less. Although the normal pressure may be sufficient as the pressure in a deaeration process, it is preferable that it is 200 torr or less, and it is more preferable that it is 100 torr or less.
In the degassing step, the end of the degassing step is when the solvent content is 5% by mass or less with respect to 100% by mass of the mixture at that time. The content of the solvent at the end of the degassing step is more preferably 3% by mass or less, still more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

As the high boiling point component, alcohol having a boiling point of 100 ° C. or higher such as 2-ethyl-1-hexanol, dodecanol, butanol and the like is preferable. More preferred is an alcohol having a boiling point of 120 ° C. or higher (specifically, 2-ethyl-1-hexanol or dodecanol), and still more preferred is an alcohol having a boiling point of 150 ° C. or higher. Thus, the composition whose high boiling point component is alcohol is preferable. Among alcohols having a boiling point of 120 ° C. or higher, 2-ethyl-1-hexanol and dodecanol are more preferable, and 2-ethyl-1-hexanol is more preferable. An alcohol having a boiling point of less than 100 ° C is preferably an alcohol having a boiling point of 100 ° C or higher because the thickening of the mixture may not be sufficiently prevented. A method for producing a curable resin composition in which the high-boiling component is an alcohol having a boiling point of 100 ° C. or higher is also a preferred embodiment of the present invention. Among alcohols having a boiling point of 120 ° C. or higher, alcohols having a boiling point of 150 ° C. or higher are more preferable, and alcohols having a boiling point of 190 ° C. or higher are more preferable.

The curable resin composition of the present invention is preferably produced by the method described above. That is, a (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, and a method for producing a curable resin composition containing a radical polymerization initiator, the curable resin composition comprising: The method includes a cationically polymerizable liquid compound having an aromatic structure, and the production method includes (meth) acrylate having 7 or more conjugated structures, a radical polymerization initiator, a cationically polymerizable liquid compound having an aromatic structure, and a solvent. A method for producing a curable resin composition comprising a step of preparing a mixture and a degassing step of degassing the solvent from the mixture, wherein the degassing step is performed in the presence of a high-boiling component is also included in the present invention. One of the preferred forms.
In the said manufacturing method, the curable resin composition manufactured contains the (meth) acrylate which has the said conjugated structure, the radical polymerization initiator, and the cationically polymerizable liquid compound which has an aromatic structure, A form containing metal oxide particles, organosiloxane and the like is also preferable. Even when an inorganic component is contained, the above-described production method can be suitably used.

When the curable resin composition contains an inorganic component, the degassing step (2) is particularly preferably performed in the presence of a high-boiling component. In this case, in the said manufacturing method, since it deaerates in the coexistence of a high boiling component and a high boiling component remains in a composition, a high boiling component will be contained in curable resin composition. As mentioned above, as a preferable form of the high boiling point component, it is a high boiling point alcohol, and is composed of an organic component containing a high boiling point component (high boiling point alcohol) (a cationic polymerizable compound is essential) and an inorganic component. A resin composition is preferred. Thus, an alcohol, a resin component, an inorganic component, and a cationic polymerization initiator having a boiling point of 100 ° C. or higher (preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and still more preferably 190 ° C. or higher). The curable resin composition containing it is also one of the preferable forms of this invention.

When the said curable resin composition contains an inorganic component, the external addition method and the internal precipitation method are used suitably as the compounding method. When the curable resin composition of the present invention is used for optical applications, when the above components are produced by an internal precipitation method, the stability of the composition is reduced by the catalyst used, and the structure and composition of the above components are controlled. There is a risk of various effects such as difficulty in curing, alteration before curing due to reaction with a resin component, residual catalyst, and residual water that is difficult to remove. Therefore, the external addition method is preferable when used for an optical member. The external addition method of the said inorganic component, specifically, the addition form to the resin composition of an inorganic component, and a dispersion are demonstrated. The form of the inorganic component is preferably mixed with the resin component in a form dissolved in a powdered or liquid medium. That is, it is preferably in the form of a solution in which the inorganic component is dissolved in the medium.

Examples of the medium include a solvent, a plasticizer, a monomer, and a liquid resin. As the solvent, water, organic solvents, mineral oils, vegetable oils, wax oils, silicone oils and the like can be suitably used, but a solvent in which the cationically polymerizable compound is easily dissolved is preferable.
As a solution containing the said solvent and an inorganic component, the form of a solvent dispersion is mentioned, for example. The content of the inorganic component in the solvent dispersion is not particularly limited, but is preferably 10 to 70% by weight, more preferably 20 to 50% by weight of the entire solvent dispersion. Easy to handle in content. Although there is no limitation in particular about content of the solvent in a solvent dispersion, Preferably it is 90-30 weight% of the whole solvent dispersion, More preferably, it is 80-50 weight%.

Examples of the organic solvent include alcohols, ketones, aliphatic and aromatic carboxylic esters, ethers, ether esters, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, and mineral oils. , Vegetable oil, wax oil, silicone oil and the like. Among these, a solvent in which the cationically polymerizable compound is easily dissolved is preferable, and specifically, ketones, aliphatic and aromatic carboxylic acid esters, ethers, aliphatic and aromatic hydrocarbons are preferable. .

The present invention is also a method of curing the curable resin composition, wherein the curable resin composition is a method of curing a (meth) acrylate having a conjugated structure having 7 or more carbon atoms and an oxetane group. It is also a curing method of a curable resin composition that cures with the compound and the radical polymerization initiator as essential components. Thus, by allowing the (meth) acrylate having the conjugated structure and the cationic polymerizable liquid compound having the aromatic structure to coexist, the curing rate of the (meth) acrylate having the conjugated structure can be improved. .

As the curing method of the curable resin composition of the present invention, various methods such as thermosetting and photocuring can be suitably used. However, the curable resin composition may be a radical polymerization initiator or other as required. A method is preferably used in which the materials are mixed to form one liquid, the liquid mixture is applied to a mold that matches the shape of the cured product and cured, and then the cured product is removed from the mold. In such a method, it is preferable that the viscosity of the curable resin composition is not significantly increased because it is easy to handle. In the case of curing by thermosetting, the curing temperature can be appropriately set according to the resin composition to be cured, but is preferably 80 to 200 ° C. More preferably, it is 100-180 degreeC, More preferably, it is 110-150 degreeC.

The curing method is preferably a method for producing a cured product by curing the cationic curable resin composition within 5 minutes. Specifically, other materials are mixed with the curable resin composition as necessary to make one liquid, and the mixed liquid is applied to a mold that matches the shape of the cured product, and cured within 5 minutes. It is preferable to make it. By performing the curing using a mold in a short time, it is possible to make the method excellent in economic efficiency. Thus, a method for producing a cured product by curing the resin composition, the production method is also a curing method for a resin composition in which the resin composition is cured within 5 minutes to produce a cured product. Moreover, it is one of the preferable forms of this invention. When the curing time (curing time using a mold) exceeds 5 minutes, the productivity is deteriorated. More preferably, it is within 3 minutes.

In the curable resin composition of this invention, after making it harden | cure using a metal mold | die as mentioned above, it is preferable to take out cured | curing material from a metal mold | die and to perform a postcure (baking). By performing post-cure, the cured product has sufficient hardness and can be suitably used for various applications. Moreover, in post-cure, it is excellent in handleability from the point of further curing a cured product having a certain degree of hardness. Therefore, there is an advantage that a large amount of products can be post-cured in a small area because it is not necessary to use a mold.
In the post-cure, the curing temperature and the curing time can be appropriately set according to the resin composition to be cured. For example, the curing temperature is preferably 80 to 200 ° C. More preferably, it is 100-180 degreeC, More preferably, it is 110-150 degreeC. The curing time for the post cure is preferably 1 to 48 hours, although it depends on the curing temperature. More preferably, it is 1-10 hours, More preferably, it is 2-5 hours.

Hereinafter, the curing method of the curable resin composition of the present invention will be further described. Various methods can be employed for curing the resin composition of the present invention depending on the properties of the resin used.
The curable resin composition of the present invention can be made into a cured product by curing using a radical polymerization initiator as a curing catalyst. It is preferable to use the above-mentioned heat latent cation generator as a curing catalyst. For the curing of the curable resin composition of the present invention, for example, a curing agent can be used. Examples of such curing agents include methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, pyromellitic anhydride, methylnadic acid, 3-methyl-1,2,3,6-tetrahydro. Acid anhydrides such as phthalic anhydride, 3-methyl-hexahydrophthalic anhydride, methyl-3,6 endomethylene-1,2,3,6-tetrahydrophthalic anhydride; phenol novolac resin, cresol novolac resin, bisphenol A Various phenol resins such as novolac resin, dicyclopentadiene phenol resin, phenol aralkyl resin and terpene phenol resin; obtained by condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde and glyoxal Price Various phenolic resins of such phenol resins; BF ₃ complex, sulfonium salts, can be used alone or in combination, such as imidazoles. Further, curing with a polyhydric phenol compound is also a preferred embodiment.

In the curing of the curable resin composition, a curing accelerator can be used as necessary. For example, triphenylphosphine, tributylhexadecylphosphonium bromide, tributylphosphine, tris (dimethoxyphenyl) phosphine, etc. 1 type, or 2 or more types, such as an organophosphorus compound, is suitable. As said hardening temperature, 70-200 degreeC is preferable. More preferably, it is 80-150 degreeC.
In addition, although the hardening agent and hardening accelerator mentioned above have advantages, such as accelerating the hardening reaction of a resin composition and being easy to handle, conventionally well-known hardening agents, such as such an acid anhydride and an amino compound Are known that the alicyclic acid anhydrides usually used for acid anhydride curing have a low refractive index and that amino compounds are easily yellowed. Therefore, when it is used for a high refractive index optical member, it is not actively used unless it is indispensable to add a curing agent and a curing accelerator, and a radical polymerization initiator or a cation as required. Curing with a polymerization initiator is preferably performed.

The curable resin composition of the present invention has the above-described configuration, has a high curing rate, is excellent in workability, and can produce a cured product having a high refractive index. Moreover, since this hardened | cured material has a high refractive index, it is used suitably for various uses, such as optical uses, such as a lens unit, and an optical device use.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

Synthesis example 1
Ogsol EA-0200 (Osaka Gas Chemical Co., Ltd., fluorene acrylate) 5.0 g, Eternacoll @ OXBP (Ube Industries, Oxetane resin) 2.0 g, JER828EL (Japan Epoxy Resin Co., Ltd., bisphenol A epoxy resin) 3.0 g Then, 0.05 g of stearic acid was mixed at 100 ° C. After cooling, 0.05 g of Sun-Aid SI-80L (manufactured by Sanshin Chemical Industry Co., Ltd., thermal acid generator) and 0.1 g of purptil (manufactured by NOF Corporation, radical generator) are added, and a revolving centrifugal mixer ( A resin composition for Example 1 was prepared by performing mixed defoaming using Shintaro Awatori (Shinky Corp.).

Synthesis example 2
Ogsol EA-0200 (Osaka Gas Chemical Co., Fluorene Acrylate) 7.0 g, Eternacoll @ OXBP (Ube Industries, Oxetane resin) 1.0 g, JER828EL (Japan Epoxy Resin Co., Ltd., bisphenol A epoxy resin) 2.0 g Then, 0.05 g of stearic acid was mixed at 100 ° C. After cooling, 0.03 g of Sun-Aid SI-80L (manufactured by Sanshin Chemical Industry Co., Ltd., thermal acid generator) and 0.14 g of purptil (manufactured by NOF Corporation, radical generator) are added, and a revolving centrifugal mixer ( A resin composition for Example 2 was prepared by performing mixed defoaming using Shintaro Awatori (Shinky Corp.).

Synthesis example 3
Ogsol EA-0200 (Osaka Gas Chemical Co., Ltd., fluorene acrylate) 7.0 g, JER828EL (Japan Epoxy Resin Co., Ltd., bisphenol A epoxy resin) 3.0 g, and stearic acid 0.05 g were mixed at 100 ° C. After cooling, 0.03 g of Sun-Aid SI-80L (manufactured by Sanshin Chemical Industry Co., Ltd., thermal acid generator) and 0.14 g of purptil (manufactured by NOF Corporation, radical generator) are added, and a revolving centrifugal mixer ( A resin composition for Example 2 was prepared by performing mixed defoaming using Shintaro Awatori (Shinky Corp.).

Synthesis example 4
10.0 g of Ogsol EA-0200 (Osaka Gas Chemical Co., Ltd., fluorene acrylate) and 0.05 g of stearic acid were mixed at 100 ° C. After cooling, 0.2 g of Purptil O (manufactured by NOF Corporation, radical generator) is added and mixed and defoamed using a self-revolving centrifugal mixing apparatus (manufactured by Shinky Co., Ltd., Nertaro Awatori). A resin composition for 1 was prepared.

Synthesis example 5
Ogsol EA-0200 (Osaka Gas Chemical Co., Ltd., fluorene acrylate) 7.0 g, TMPTA (Kyoeisha Chemical Co., Ltd., trimethylolpropane triacrylate), and stearic acid 0.05 g were mixed at 100 ° C. After cooling, 0.2 g of Purptil O (manufactured by NOF Corporation, radical generator) is added and mixed and defoamed using a self-revolving centrifugal mixing apparatus (manufactured by Shinky Co., Ltd., Nertaro Awatori). A resin composition for 2 was prepared.

Examples 1-3, Comparative Examples 1 and 2
Using the method shown below, the curing rate of the obtained resin composition, the measurement of the refractive index, the workability evaluation, and the curing shrinkage evaluation were performed. The evaluation method is shown below.

<Measurement of curing rate>
1 g of the obtained resin composition (resin composition for Examples 1 to 3 and resin composition for Comparative Examples 1 and 2) was dropped on a hot plate adjusted to 130 ° C., and a radiation thermometer (IT, manufactured by Horiba, IT -540E), the temperature of the resin surface was measured. The curing rate was compared by examining the exothermic temperature. The measurement results are shown in Table 1 below. As an index of the curing rate, the time for the exothermic peak to appear was shown. The exothermic peak is indicated by the time when the temperature once rises during the curing and then starts to decrease.

<Refractive index measurement method>
The obtained resin composition was coated on a glass plate with a 10 mil applicator, cured at 150 ° C. for 4 hours, and the coating film was peeled off from the glass plate to obtain a 250 μm film. The refractive index of 589 nm at 20 ° C. of the film obtained using a refractometer (Atago Co., Ltd., DR-M2) was measured. The measurement results are shown in Table 1 below.

<Workability evaluation method>
The viscosity of the resin composition was measured with an R / S rheometer (manufactured by Brookfield, USA) at a rotation speed D = 1 / s at 25 ° C. An RC25-1 measuring jig was used at a viscosity of 20 Pa · S or more, and an RC50-1 jig was used at a viscosity of less than 20 Pa · s. As for the viscosity of the resin composition, the value of the rotational speed D = 5 to 100 / s is extrapolated for those for which the viscosity at the rotational speed D = 1 / s cannot be measured. Those having a resin viscosity of 100 Pa · s or less were rated as “○” and those having a resin viscosity of 100 Pa · s or more as “X”.

<Method for evaluating curing shrinkage>
The obtained resin composition was coated in a glass plate shape with a 10 mil applicator, and when it was heated at 130 ° C. under nitrogen, the crack did not occur, and the entered one was marked with ×.

In Examples 1 to 3, the refractive index is 1.60 or more, which is excellent in workability and curing shrinkage, and since the exothermic peak was confirmed in 25 seconds, the curing rate was sufficient. I found out. In Comparative Example 1, the viscosity was high and the workability was poor. In Comparative Example 2, it was not preferable in terms of curing shrinkage. From these results, the curable resin composition of the present invention had a high refractive index, excellent workability, and small cure shrinkage. Furthermore, the curing speed was also excellent.

Claims (8)

A (meth) acrylate having a conjugated structure composed of 7 or more carbon atoms, and a curable resin composition containing a radical polymerization initiator,
The curable resin composition further comprises a cationically polymerizable liquid compound having an aromatic structure as an essential component. The curable resin composition according to claim 1, wherein the curable resin composition further contains a cationic polymerization initiator as an essential component. The curable resin composition according to claim 1 or 2, wherein the cationic polymerizable liquid compound having an aromatic structure essentially comprises a compound having an epoxy group and / or a compound having an oxetane group. The curable resin according to any one of claims 1 to 3, wherein the conjugated structure essentially includes at least one structure selected from the group consisting of a fluorene skeleton, an anthracene ring, a dibenzothiophene ring, and a carbazole skeleton. Composition. A cured product obtained by curing the curable resin composition according to claim 1. The cured product according to claim 5, wherein the cured product has a refractive index of 1.60 or more. An optical member comprising the cured product according to claim 5. An optical unit comprising the optical member according to claim 7.