JP2012140501A - Photocurable resin composition and optical material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable resin composition which can attempt the improvement of the refractive index and can simultaneously attempt the improvement of transparency, heat resistance and handleability, and to provide an optical material.SOLUTION: The photocurable resin composition contains an epoxy resin having two or more epoxy groups in one molecule, a photopolymerization initiator composed of an anion component and a cation component, and at least one alkoxysilane compound selected from the group consisting of methyltrimethoxysilane, 1,2-bis(trimethoxysilyl)ethane, and benzyltriethoxysilane.

Description

  The present invention relates to a photocurable resin composition and an optical material, and more particularly to a photocurable resin composition and an optical material that can be widely used for optical products.

  Various materials have been studied as materials for adhesives and sealants for optical parts and optical lenses.

  Among these various materials, a photocurable resin composition mainly composed of an epoxy resin having a high refractive index and excellent heat resistance has attracted attention from the viewpoint of thinning an optical lens and increasing the resolution of an image. ing.

  As such a photocurable resin composition, for example, a photosensitive composition comprising an epoxy compound, a photocationic polymerization initiator, and a hydroxyl group-containing compound (for example, water) having a boiling point of 60 to 160 ° C. has been proposed. (For example, Patent Document 1).

JP 2008-31438 A

  However, a photocurable composition containing an epoxy compound as a main component, such as the photosensitive composition described in Patent Document 1, may turn yellow and decrease transparency when heated after photocuring. In addition, such a photocurable resin generally has a disadvantage that it has a high viscosity and is not easy to handle.

  Then, this invention is providing the photocurable resin and optical material which can aim at the improvement of transparency, heat resistance, and handleability, while improving a refractive index.

  In order to achieve the above object, the photocurable resin composition of the present invention comprises an epoxy resin having two or more epoxy groups in one molecule, a photopolymerization initiator comprising an anionic component and a cationic component, It is characterized by containing at least one alkoxysilane compound selected from the group consisting of methoxysilane, 1,2-bis (trimethoxysilyl) ethane, and benzyltriethoxysilane.

  Moreover, in the photocurable resin composition of this invention, it is suitable that the mixture ratio of the said alkoxysilane compound is 0.5-5 mass parts with respect to 100 mass parts of said epoxy resins.

  The optical material of the present invention is characterized by being obtained by curing the above-described photocurable resin composition.

  Since the photocurable resin composition of this invention contains an epoxy resin, it can ensure a high refractive index. Moreover, since it contains at least one alkoxysilane compound selected from the group consisting of methyltrimethoxysilane, 1,2-bis (trimethoxysilyl) ethane, and benzyltriethoxysilane, it is heated after photocuring. However, discoloration and loss of transparency can be reduced, and the liquid state can be obtained at room temperature, thereby improving the handleability.

  Therefore, the photocurable resin composition and the optical material of the present invention can improve transparency, heat resistance, and handleability while improving the refractive index.

  The photocurable resin composition of the present invention comprises an epoxy resin (A) having two or more epoxy groups in one molecule, a photopolymerization initiator (B) comprising an anionic component and a cationic component, and an alkoxysilane compound. (C).

  Although it does not restrict | limit especially as an epoxy resin (A), For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, etc. Bisphenol type epoxy resin, for example, novolak type epoxy resin such as phenol novolak type epoxy resin, for example, linear aliphatic type epoxy resin, for example, alicyclic epoxy resin such as dicyclocyclic type epoxy resin, for example, fluorene type epoxy resin Etc.

  Such an epoxy resin (A) may be used alone or in combination.

  Among such epoxy resins (A), in view of the refractive index, preferably, an epoxy resin having a refractive index of 1.5 to 1.7 at a wavelength of 589 nm after curing is mentioned, and more preferably, Examples thereof include bisphenol type epoxy resins such as bisphenol A type epoxy resins, alicyclic epoxy resins, and fluorene type epoxy resins.

  Moreover, such an epoxy resin (A) has an epoxy equivalent of, for example, 50 to 500 g / eq, or preferably 100 to 300 g / eq.

  The blending ratio of the epoxy resin (A) is, for example, 30 to 100 parts by mass, preferably 35 to 100 parts by mass of the organic component (described later) excluding the photopolymerization initiator (B) and the alkoxysilane compound (C). -100 mass parts.

  When the blending ratio of the epoxy resin (A) is less than 30 parts by mass, the optical material obtained by curing the photocurable resin composition may be brittle and heat resistance may be reduced. On the other hand, when the blending ratio of the epoxy resin (A) is within the above range, the heat resistance of the optical material can be improved.

  Moreover, the mixture ratio of the epoxy resin (A) with respect to 1 mass part of photoinitiators (B) is 10-400 mass parts, for example, Preferably, it is 20-300 mass parts.

  Moreover, the mixture ratio of the epoxy resin (A) with respect to the photocurable resin composition whole quantity is 20-99 mass%, for example, Preferably, it is 30-99 mass%.

  The photopolymerization initiator (B) is a cationic polymerization initiator that generates a cationic species to cure the epoxy resin, and examples thereof include an onium salt composed of an anionic component and a cationic component.

Examples of the anion component include phosphate ions such as PF ₆ ⁻ and PF ₄ (CF ₂ CF ₃ ) ₂ ^— , antimonate ions such as SbF ₆ ^—, and sulfonate ions such as trifluoromethanesulfonate, and the like. Is mentioned.

  Examples of the cation component include sulfonium such as aromatic sulfonium, iodonium such as aromatic iodonium, phosphonium such as aromatic phosphonium, and sulfoxonium such as aromatic sulfoxonium.

  Examples of such an onium salt include a sulfonium salt such as an aromatic sulfonium salt, an iodonium salt such as an aromatic iodonium salt, a phosphonium salt such as an aromatic phosphonium salt, an aromatic sulfone having the above-described anion component as a counter anion. Examples include sulfoxonium salts such as xonium salts.

  Such a photoinitiator (B) may be used alone or in combination.

  Of these photopolymerization initiators (B), an aromatic sulfonium salt is preferably used in consideration of photocurability.

  Such a photopolymerization initiator (B) can also be prepared as a photopolymerization initiator solution by dissolving the above-described onium salt in an organic solvent such as propylene carbonate.

  The density | concentration of such a photoinitiator solution is 30-70 mass%, for example, Preferably, it is 40-60 mass%.

  The blending ratio of the photopolymerization initiator (B) is, for example, 0.05 to 5 parts by mass, preferably 0.05 to 3 parts per 100 parts by mass of the organic component (described later) excluding the alkoxysilane compound (C). Part by mass, more preferably 0.05 to 2.5 parts by mass.

  When the blending ratio of the photopolymerization initiator (B) is less than 0.05 parts by mass, the curability of the photocurable resin composition is lowered, and when it exceeds 5 parts by mass, the photocurable resin composition is cured. By doing so, the transparency of the optical material obtained may be reduced. On the other hand, when the blending ratio of the photopolymerization initiator (B) is within the above range, the curability of the photocurable resin composition and the transparency of the optical material can be improved.

  Moreover, the mixture ratio of the photoinitiator (B) with respect to the photocurable resin composition whole quantity is 0.05-3 mass%, for example, Preferably, it is 0.1-2 mass%.

  The alkoxysilane compound (C) is a compound in which an alkoxy group is bonded to silicon, and examples thereof include methyltrimethoxysilane, 1,2-bis (trimethoxysilyl) ethane, and benzyltriethoxysilane.

  The compounding ratio of the alkoxysilane compound (C) is, for example, 0.5 to 8 parts by mass, or preferably 0.5 to 6 parts by mass with respect to 100 parts by mass of the epoxy resin (A).

  If the compounding ratio of the alkoxysilane compound (C) is less than 0.5 parts by mass, the transparency of the optical material obtained by curing the photocurable resin composition cannot be improved, and 8 masses. If the portion is exceeded, the optical material may become brittle. On the other hand, when the mixing ratio of the alkoxysilane compound (C) is within the above range, the transparency and mechanical strength of the optical material can be improved.

  Moreover, the mixture ratio of the alkoxysilane compound (C) with respect to 1 mass part of photoinitiators (B) is 0.5-15 mass parts, for example, Preferably, it is 1-10 mass parts.

  Moreover, the mixture ratio of the alkoxysilane compound (C) with respect to the photocurable resin composition whole quantity is 0.1-8 mass%, for example, Preferably, it is 0.5-5 mass%.

  Such a photocurable resin composition is prepared by, for example, heating and melting and mixing an epoxy resin (A), a photopolymerization initiator (B), and an alkoxysilane compound (C). .

  As conditions for heat-melt mixing, heating temperature is 40-150 degreeC, for example, Preferably, it is 40-130 degreeC.

  The photocurable resin composition of the present invention preferably further contains an araliphatic compound (D).

  The araliphatic compound (D) is an araliphatic compound in which an aliphatic group to which a hydroxyl group is bonded is bonded to an aromatic ring, and examples of the aliphatic group to which a hydroxyl group is bonded include those having 1 to 18 carbon atoms Linear or branched hydroxyalkyl groups, such as hydroxyalkylene groups having 1 to 5 carbon atoms and 1 to 4 carbon atoms of the aromatic ring; As an aromatic ring, a C6-C18 aromatic ring is mentioned, for example.

  More specifically, examples of such a hydroxyalkyl group include a hydroxymethyl group, a hydroxyethyl group, a hydroxy n-propyl group, a hydroxyisopropyl group, a hydroxy n-butyl group, a hydroxyisobutyl group, and a hydroxy sec-butyl group. , A linear or branched hydroxyalkyl group having 1 to 18 carbon atoms such as hydroxy tert-butyl group and hydroxy n-hexyl group.

  Examples of such a hydroxy 5- to 6-membered ring include a hydroxycyclopentane ring, a hydroxycyclohexane ring, a (hydroxymethyl) -cyclopentane ring, a (hydroxymethyl) -cyclohexane ring, and a (hydroxyethyl) -cyclopentane ring. And a 5- to 6-membered ring having 5 to 18 carbon atoms.

  Moreover, as such an aromatic ring, C6-C18 aromatic rings, such as a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, are mentioned, for example.

  Such aliphatic groups are substituted, for example 1 to 4 on the aromatic ring.

Examples of such an araliphatic compound (D) include 1-indanol (the following chemical formula (1)), 2-indanol (the following chemical formula (2)), 9-fluorenylmethanol (the following chemical formula (3)). Benzene cycloalkyl alcohol compounds such as 2- (1-naphthyl) ethanol (the following chemical formula (4)), 1- (1-naphthyl) ethanol (the following chemical formula (5)), 2-naphthylmethanol (the following chemical formula ( 6)) and the like, for example, 2-phenylethyl alcohol (the following chemical formula (7)), 2-phenyl-2-propanol (the following chemical formula (8)), 2-methyl-1-phenyl- 2-propanol (the following chemical formula (9)), 1,4-bis (2-hydroxyethyl) benzene (the following chemical formula (10)), 1-phenyl Benzene alkyl alcohol compounds such as 2-propanol (the following chemical formula (11)), such as 4-hydroxymethylbiphenyl (the following chemical formula (12)), 4- (1-hydroxyethyl) biphenyl (the following chemical formula (13) ), 2- (4-biphenyl) -2-propanol (the following chemical formula (14)), and the like.
Chemical formula (1):

Chemical formula (2):

Chemical formula (3):

Chemical formula (4):

Chemical formula (5):

Chemical formula (6):

Chemical formula (7):

Chemical formula (8):

Chemical formula (9):

Chemical formula (10):

Chemical formula (11):

Chemical formula (12):

Chemical formula (13):

Chemical formula (14):

  Such an araliphatic compound (D) may be used alone or in combination.

  Of these araliphatic compounds (D), 2-indanol (the above chemical formula (2)), 2-naphthylmethanol (the above chemical formula (6)), 2-phenylethyl alcohol (the above chemical formula) are preferable. (7)), 1-phenyl-2-propanol (the above chemical formula (11)), 4-hydroxymethylbiphenyl (the above chemical formula (12)).

  In order to contain such an araliphatic compound (D) in the photocurable resin composition, for example, the araliphatic compound (D) is added during the above-described heat-melt mixing.

  The blending ratio of the araliphatic compound (D) is, for example, 1 to 20 parts by mass, preferably 3 to 15 parts by mass with respect to 100 parts by mass of the organic component (described later) excluding the araliphatic compound (D). is there.

  If the blending ratio of the araliphatic compound (D) is less than 1 part by mass, the transparency of the optical material obtained by curing the photocurable resin composition cannot be improved. When exceeding, the optical material may become fragile. On the other hand, when the blending ratio of the araliphatic compound (D) is within the above range, the transparency and mechanical strength of the optical material can be improved.

  That is, the transparency of the optical material can be improved by blending the araliphatic compound (D). Moreover, since the viscosity of a photocurable resin composition can be reduced, handling improvement can also be aimed at. In particular, by blending the araliphatic compound (D) with a photocurable resin composition containing a high refractive index epoxy resin, a decrease in the refractive index after photocuring can be suppressed, and transparency and handling properties are improved. Can be improved.

  Moreover, the mixture ratio of the araliphatic compound (D) with respect to the photocurable resin composition whole quantity is 1-20 mass%, for example, Preferably, it is 5-15 mass%.

  In addition to the above components, the photocurable resin composition of the present invention includes, as an organic additive, for example, an oxetane resin, and if necessary, a photocurable resin composition on a transparent substrate such as glass. When an optical material is produced by curing an object, a silane or titanate coupling agent is used for the purpose of improving the adhesion between the transparent substrate and the optical material, and an anthracene or the like is used for the purpose of improving the curability. A monofunctional epoxy resin may be added for the purpose of sensitizers, acid multipliers, and fluidity. In addition, flexibility imparting agents such as synthetic rubbers and silicone compounds, oxidation, etc., depending on the purpose and application. An inhibitor, an antifoaming agent, a dye, etc. can also be mix | blended in an appropriate ratio. Moreover, as an inorganic additive, a pigment, an inorganic filler, etc. can also be mix | blended in a suitable ratio, for example.

  Examples of the oxetane resin include 4,4′-bis (3-methyloxetane-3-ylmethyloxymethyl) biphenyl, 4,4′-bis (3-ethyloxetane-3-ylmethyloxymethyl) biphenyl, 4 -(3-ethyloxetane-3-ylmethyloxymethyl) -4 '-(3-methyloxetane-3-ylmethyloxymethyl) biphenyl, 4- (3-propyloxetane-3-ylmethyloxymethyl) -4 Examples include '-(3-methyloxetane-3-ylmethyloxymethyl) biphenyl.

  Such oxetane resins may be used alone or in combination.

  Among such oxetane resins, 4,4′-bis (3-ethyloxetane-3-ylmethyloxymethyl) biphenyl is preferable.

  The mixing ratio of the oxetane resin is, for example, 5 to 250 parts by mass, or preferably 10 to 200 parts by mass with respect to 100 parts by mass of the epoxy resin (A).

  Moreover, the mixture ratio of oxetane resin with respect to the photocurable resin composition whole quantity is 3-70 mass%, for example, Preferably, it is 5-65 mass%.

  By mix | blending such an oxetane resin, the sclerosis | hardenability improvement of a photocurable resin composition can be aimed at.

  That is, the photocurable resin composition of the present invention includes an epoxy resin (A), a photopolymerization initiator (B), an alkoxysilane compound (C), an araliphatic compound (D), and an oxetane resin. It contains an organic component composed of an organic additive and an inorganic component composed of an inorganic additive.

  For example, such a photocurable resin composition is potted on a transparent substrate such as glass, and then filled with the desired mold by pressing a desired mold. And after irradiating light and hardening a photocurable resin composition, the optical material integrated with the transparent substrate is obtained by removing a shaping | molding process type | mold.

  Examples of the apparatus used for the light irradiation include an ultraviolet (UV) lamp, a single band lamp having a specific wavelength, and the like.

The conditions of light irradiation are not particularly limited, the amount of irradiation, for example, 2000~20000mJ / cm ^2, preferably from 2000~15000mJ / cm ^2.

If the irradiation amount is less than 2000 mJ / cm ² , the photocurable resin composition cannot be sufficiently cured, and the resulting optical material may not be molded into a desired shape on the transparent substrate. is there. Moreover, when it exceeds 20000 mJ / cm < ² >, there exists a malfunction that the photodegradation by excessive irradiation arises.

  On the other hand, if the irradiation amount is within the above range, the photocurable resin composition can be sufficiently cured, so that the optical material can be molded into a desired shape on the transparent substrate, and excessively Photodegradation due to irradiation can be prevented.

  Furthermore, the optical material integrated with the transparent substrate is heat-treated at a predetermined temperature as necessary.

  As conditions for the heat treatment, the heat treatment temperature is, for example, 50 to 200 ° C., preferably 80 to 170 ° C., and the heat treatment time is, for example, 0.5 to 3 hours, preferably 0.5 to 2 hours.

  Furthermore, the heat treatment can improve the adhesion between the substrate and the cured resin.

  Such a photocurable resin composition includes at least one alkoxysilane compound (C) selected from the group consisting of methyltrimethoxysilane, 1,2-bis (trimethoxysilyl) ethane, and benzyltriethoxysilane. ). Therefore, it becomes liquid at room temperature, and the handleability can be improved.

  Moreover, the optical material obtained by curing such a photocurable resin composition can reduce discoloration and loss of transparency even when heated.

  Therefore, the photocurable resin composition and the optical material of the present invention can improve transparency, heat resistance, and handleability while improving the refractive index.

  Applications of the photocurable resin composition of the present invention are excellent in transparency and heat resistance, and therefore include, for example, molding materials for optical components such as optical lenses, photocurable adhesives for fixing optical components, and the like.

  More specifically, the photocurable resin composition can be integrated with the transparent substrate by curing on a transparent substrate such as glass, and can be manufactured as a high-quality hybrid lens.

  Moreover, it can also manufacture as a molding material for optical components which can be mounted in a printed circuit board by the solder reflow under high temperature.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these.

Examples 1 to 11 and Comparative Examples 1 and 2
In the formulation shown in Table 1, each component was blended and melt mixed to prepare a photocurable resin composition.

(Evaluation)
About the photocurable resin composition prepared by each Example and the comparative example, the viscosity measurement, the heat-resistant discoloration (transparency) test, and the refractive index measurement were implemented as follows. The results are shown in Table 1.
(1) Viscosity measurement Using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity at 25 ° C. of the photocurable resin composition prepared in each of the examples and comparative examples was measured.
(2) Heat-resistant discoloration (transparency) test Polyethylene terephthalate (PET) film (Diafoil MRF-50) obtained by subjecting the photocurable resin compositions prepared in each Example and Comparative Example to a silicone release treatment. (Manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) so as to have a thickness of 600 μm, and this was irradiated with light (amount of light of 8000 mJ / cm ² ) and primarily cured. Then, each optical material integrated with the PET film was obtained by heat treatment at 150 ° C. for 1 hour. These optical materials were cut out as 3 cm square test pieces, and the cut out test pieces were passed through a reflow oven at 260 ° C. for 10 seconds, and then transmitted through a color computer (SM-T, manufactured by Suga Test Instruments Co., Ltd.). The yellow index value (YI value) of the test piece was measured. The numerical value indicates that the lower the value, the lower the color change and the higher the transparency. I. A value of 40 or less was evaluated as A, less than 80 as B, and 80 or more as C.
(3) Refractive index measurement The photocurable resin composition prepared in each Example and Comparative Example was poured into a 1 × 1.5 × 0.5 cm transparent mold and irradiated with ultraviolet rays (UV) at 16000 mJ. After being cured, it was removed from the mold and heat-treated at 150 ° C. for 1 hour to obtain each optical material. The surface of the obtained optical material was polished with a grinder, and the refractive index of the optical material at 25 ° C. was measured using a refractometer (manufactured by Atago Co., Ltd.).

The abbreviations in Table 1 are shown below.
Epoxy resin (A)
A-1: Bisphenol A type epoxy resin (epoxy equivalent 185 g / eq., Viscosity 1000 mPa · s)
A-2: Bisphenol F type epoxy resin (epoxy equivalent 160 g / eq., Viscosity 1300 mPa · s)
A-3: Fluorene type epoxy resin (epoxy equivalent 243 g / eq., Viscosity 0.6 Pa · s (150 ° C.))
A-4: Alicyclic epoxy resin (Celoxide 2021P, epoxy equivalent 138 g / eq., Viscosity 150 to 400 mPa · s (25 ° C.), manufactured by Daicel Chemical Industries)
Photopolymerization initiator (B): Triarylsulfonium photopolymerization initiator (anion component: PF ₄ (CF ₂ CF ₃ ) ₂ ⁻ , cation component: chemical formula (15) below, concentration 50% by mass (solvent: propylene carbonate)
Chemical formula (15):

Alkoxysilane compound (C)
C-1: Methyltrimethoxysilane C-2: 1,2-bis (trimethoxysilyl) ethane C-3: benzyltriethoxysilane araliphatic compound (D)
D-1: 1-phenyl-2-propanol (the above chemical formula 11)
D-2: 2-Phenyl-ethyl alcohol (the above chemical formula 7)
D-3: 2-indanol (the above chemical formula 2)
D-4: 2-naphthylmethanol (the above chemical formula 6)
Oxetane resin: 4,4′-bis (3-ethyloxetane-3-ylmethyloxymethyl) biphenyl

Claims (3)

An epoxy resin having two or more epoxy groups in one molecule;
A photopolymerization initiator comprising an anionic component and a cationic component;
Photocurability comprising methyltrimethoxysilane, 1,2-bis (trimethoxysilyl) ethane, and at least one alkoxysilane compound selected from the group consisting of benzyltriethoxysilane Resin composition.   The photocurable resin composition according to claim 1, wherein a mixing ratio of the alkoxysilane compound is 0.5 to 5 parts by mass with respect to 100 parts by mass of the epoxy resin.   An optical material obtained by curing the photocurable resin composition according to claim 1.