JP6521237B2 - Photocurable composition - Google Patents

Description

The present invention relates to a photocurable composition in which the cured product does not become turbid even when it is left in a high temperature and high humidity atmosphere.

It is known that it is difficult to maintain barrier properties (moisture resistance) in a high-temperature, high-humidity atmosphere (such as an atmosphere of 60 ° C. × 95% RH) that has a photocurable acrylic resin composition. If exposed to such an environment, it is known that the cured product of the photocurable composition absorbs moisture and swells, or the cured product becomes cloudy. In order to improve moisture resistance, a method of forming an inorganic layer as in Patent Document 1 has been proposed. However, since the number of processes increases during implementation, a photocurable composition having high moisture resistance has been required.

JP, 2010-228412, A

In the conventional photocurable composition, when the cured product is soft, a phenomenon such as the cured product becomes clouded particularly in a high temperature and high humidity atmosphere occurs, and it is difficult to impart high moisture resistance.

As a result of intensive studies to achieve the above object, the present inventors have found a method for a photocurable composition, and have completed the present invention.

The gist of the present invention will now be described. The first embodiment of the present invention comprises the components (A) to (E) and contains 70% by mass or less of the component (B-1) with respect to the entire component (B), and the component (B-2) is It is a photocurable composition containing 30 mass% or more.
(A) Component: (Meth) Acrylic Oligomer (B) Component: (B) Component and (B-2) Component (Meth) Acrylic Monomer (B-1) Component: Having an Aliphatic Hydrocarbon Group ( Meta) acrylic monomer (B-2) component: (meth) acrylic monomer having hydroxyl group (C) component: polythiol compound (D) component: photoinitiator (E) component: the surface is untreated and the specific surface area is 100 to 500 m ² / g amorphous silica powder

A second embodiment of the present invention is the photocurable composition according to the first embodiment, wherein the component (B-1) is a (meth) acrylic monomer having an aliphatic hydrocarbon group of the general formula 1 It is.

The third embodiment of the present invention is photocurable according to any of the first and second embodiments, wherein the component (B-2) is a (meth) acrylic monomer having a hydroxyl group of the general formula 2 It is a composition.

A fourth embodiment of the present invention is the photocurable composition according to any one of the first to third embodiments, wherein the component (B) contains a (meth) acrylic monomer having an isocyanurate skeleton. is there.

The 5th embodiment of this invention is a photocurable in any one of the 1st-4th embodiment which contains 50-150 mass parts of (B) components with respect to 100 mass parts of (A) components. It is a composition.

The sixth embodiment of the present invention is photocurable according to any one of the first to fifth embodiments, wherein the component (A) comprises 5 to 25 parts by mass of the component (C) relative to 100 parts by mass. It is a composition.

A seventh embodiment of the present invention is a sealant comprising the photocurable composition according to any one of the first to sixth embodiments.

The present invention is a photocurable composition in which the cured product is soft, and the total light transmittance measurement of the cured product is high even when exposed to a high temperature and high humidity atmosphere, and the haze is low and the moisture resistance is high. Since the viscosity of the curable composition is low and the thixotropy is high, it is suitable for workability.

The details of the invention will now be described. Component (A) which can be used in the present invention is an oligomer having an acrylic group and / or a methacrylic group. Hereinafter, acrylic and methacrylic are collectively called (meth) acrylic. The component (A) can be used if the compatibility between the component (B) and the component (C) of the present invention is good.

Specific examples of (meth) acrylate oligomers include (meth) acrylate oligomers having an ester bond in the molecule, (meth) acrylate oligomers having an ether bond, (meth) acrylate oligomers having a urethane bond, epoxy-modified (meth) acrylate Oligomers and the like can be mentioned, and the main skeleton thereof can be, but is not limited to, bisphenol A, novolac phenol, polybutadiene, polyester, polyether and the like. Further, the component (A) which can be used in the present invention also includes a compound having one or more epoxy groups and one or more (meth) acrylic groups in one molecule.

As a (meth) acrylic oligomer having an ester bond, synthesis is carried out in which an ester bond is formed by synthesis of a polyol and a polyvalent carboxylic acid, and acrylic acid is added to unreacted hydroxyl groups, but this synthesis method It is not limited to Specifically, Alonix M-6100, M-6200, M-6250, M-6500, M-7100, M-7300 K, M-8030, M-8060, M-8100, M-8530, manufactured by Toa Gosei Co., Ltd. M-8560, M-9050, and the like include, but are not limited to, UV-3500BA, UV-3520TL, UV-3200B, UV-3000B, and the like manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

As a (meth) acrylic oligomer having an ether bond, there is known a synthesis method in which acrylic acid is added to a hydroxyl group of a polyether polyol or an aromatic hydroxyl group such as bisphenol, but limited to this synthesis method Absent. As a specific example, UV-6640B, UV-6100B, UV-3700B, etc. manufactured by Nippon Synthetic Chemical Industry Co., Ltd., light (meth) acrylate 3EG-A, 4EG-A, 9EG-A, 14EG- manufactured by Kyoeisha Chemical Co., Ltd. A, PTMGA-250, BP-4EA, BP-4PA, BP-10EA, etc. include EBECRYL 3700 manufactured by Daicel-Cytec Co., Ltd., but not limited thereto.

As a (meth) acrylic oligomer having a urethane bond, synthesis is known in which a urethane bond is formed by a polyol and a polyisocyanate, and a compound having acrylic acid or a hydroxyl group and a (meth) acrylic group is added to an unreacted isocyanate group. It is done. As a skeleton of the said polyol, although an alkylene oxide polyol, a polycarbonate polyol, a polyester polyol etc. can be used, it is not limited to these. Specific examples thereof include AH-600, AT-600, UA-306H, UF-8001, etc. manufactured by Kyoeisha Chemical Co., Ltd., having a polyether skeleton manufactured by Negami Industrial Co., Ltd., UN-6200, UN-6202, UN- 6300, UN-6301, UN-7600 having a polyester skeleton, UN-7700, UN-9000PEP having a polycarbonate skeleton, UN-9200A and the like, but it is not limited thereto. The component (A) is preferably a urethane-modified (meth) acrylic oligomer because the cured product becomes soft.

As epoxy modified (meth) acrylic oligomers, those obtained by adding (meth) acrylic acid to epoxy groups are known. As a specific example, Ebecryl 3700 manufactured by Daicel Ornex Co., Ltd. or the like is known, but it is not limited thereto.

The component (B) which can be used in the present invention is a (meth) acrylic monomer containing the components (B-1) and (B-2). Component (B-1) and component (B-2) are compounds having one (meth) acrylic group in the molecule, and component (B-1) is a (meth) acrylic monomer having an aliphatic hydrocarbon group And the (B-2) component is a (meth) acrylic monomer having a hydroxyl group. The aliphatic hydrocarbon group of the component (B-1) is a group composed of only carbon and hydrogen which does not have a cyclic structure, and does not contain other functional groups. The hydroxyl group of the component (B-2) is a structure including a hydroxyl group in a hydrocarbon group. The component (B) is a component from which the component (A) is removed.

In particular, the component (B-1) is preferably a (meth) acrylic monomer having an aliphatic hydrocarbon group as represented by the general formula 1. Here, R is hydrogen or a methyl group, and n is an integer of 1 to 20. Moreover, it is preferable that (B-2) component is a (meth) acrylic monomer which has a hydroxyl group like General formula 2. Here, R is hydrogen or a methyl group, m shows the integer of 3-10. Specific examples of the component (B-1) include isonononyl acrylate, lauryl acrylate and the like, and specific examples of the component (B-2) include 4-hydroxybutyl acrylate and the like.

The component (B-1) contains 70% by mass or less and the component (B-2) contains 30% by mass or more based on the total amount of the component (B). Furthermore, it is preferable that 30-60 mass% of the (B-2) component is included while 30-70 mass% of the (B-1) component is contained with respect to the whole (B) component. When the amount of the component (B-1) is more than 70% by mass, the cured product becomes hard, and when the amount of the component (B-2) is less than 30% by mass, haze occurs after a moisture resistance test.

The component (B) may be used in addition to the components (B-1) and (B-2), and may be monofunctional, bifunctional, trifunctional and polyfunctional (meth) acrylic monomers Can be mentioned. In particular, in order to improve adhesion and toughness, it is preferable to include a (meth) acrylic monomer having an isocyanurate skeleton. The component (B) preferably has a molecular weight of 1000 or less, or a viscosity of 1000 mPa · s or less at 25 ° C., in order to retain a dilution ability.

Specific examples of monofunctional monomers include (meth) acrylic acid, ethyl carbitol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone modified tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclo Pentanyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, nonyl phenoxy Ethyl (meth) acrylate, nonyl phenoxy tetraethylene glycol (meth) acrylate, methoxy diethylene glycol (meth) acrylate , Ethoxydiethylene glycol (meth) acrylate, butoxyethyl (meth) acrylate, butoxy triethylene glycol (meth) acrylate, 2-ethylhexyl polyethylene glycol (meth) acrylate, nonylphenyl polypropylene glycol (meth) acrylate, methoxydipropylene glycol (meth ) Acrylate, glycidyl (meth) acrylate, glycerol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, ethylene oxide (hereinafter abbreviated as EO) modified phthalic acid (meth) acrylate, EO modified succinic acid Meta) acrylate, caprolactone modified 2-hydroxyethyl (meth) acrylate, N, N-dimethylamino Le (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, morpholino (meth) acrylate, but EO-modified phosphoric acid (meth) acrylate and the like, but is not limited thereto.

Specific examples of the difunctional monomer include 1,3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, neopentyl glycol di ( Meta) acrylate, 1,6-hexaneglycol di (meth) acrylate, ethylene glycol diacrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, EO Modified neopentyl glycol di (meth) acrylate, propylene oxide side (hereinafter abbreviated as PO) modified neopentyl glycol di (meth) acrylate, hydroxypivalic acid ester neopentyl glycol di (meth) acrylate , Caprolactone modified hydroxypivalate ester neopentyl glycol di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, stearic acid modified pentaerythritol di (meth) acrylate, dicyclopentenyl di (meth) acrylate, EO-modified dicyclopentenyl di (meth) acrylate, diacryloyl isocyanurate and the like can be mentioned, but it is not limited thereto.

Specific examples of the trifunctional monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, ECH The modified trimethylolpropane tri (meth) acrylate, ECH modified glycerol tri (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, ethylene oxide modified isocyanurate ethylene oxide modified di and triacrylate, etc. may be mentioned, but Absent.

Specific examples of the polyfunctional monomer include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, and dipentamer. Examples include erythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate and the like, but are not limited thereto.

It is preferable that 50-150 mass parts of (B) components are added with respect to 100 mass parts of (A) components. When the component (B) is contained in an amount of 50 parts by mass or more, the viscosity is adjusted to a low viscosity to improve the handling property, and when the component is contained in an amount of 150 parts by mass or less, the photocurability is maintained.

The component (C) that can be used in the present invention is a polythiol compound. In particular, they are compounds having 2 to 6 thiol groups in the molecule. By adding the component (C), tackiness disappears on the surface of the cured product of the photocurable composition.

Specific examples of the component (C) include tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercapto) Propionates), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate and the like, but it is not limited thereto. Specific commercial products include TEMPIC, PEMP, PEMP-20P, DPMP, TMMP manufactured by SC Organic Chemical Co., Ltd., TMTP, PETP, TMTG, PETG manufactured by Sakai Chemical Co., Ltd., but are limited thereto. It is not a thing.

It is preferable that 0.1-30 mass parts of (C) components are added with respect to 100 mass parts of (A) components, and it is especially preferable that 5-25 mass parts of (C) components are added. When the amount of the component (C) is more than 0.1 parts by mass, the surface curability is improved to eliminate the tack, and when the amount of the component (C) is less than 30 parts by mass, unevenness in curing of the photocurable composition does not occur.

The component (D) that can be used in the present invention is a photoinitiator, and in order to cure the (meth) acrylic monomers of the components (A) and (B), energy rays such as ultraviolet light and visible light are used. Disassemble when irradiated. Particularly preferred are photoinitiators that generate radical species when irradiated with energy rays.

Specific examples of component (D) include acetophenone, propiophenone, benzophenone, xanthol, fluorein, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 4 -Methoxyacetophenone, 3-bromoacetophenone, 2,2-diethoxyacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 2,4,6-trimethylbenzophenone, oligo (2-hydroxy-2-methyl-1- (4- (4- 1-methylvinyl) phenyl) propanone), 4-allylacetophenone, camphorquinone, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, 4-methyl benzophenone, 4-chloro -4'-benzylbenzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro-8- Nonylxanthone, benzoyl, benzoyl methyl ether, benzoin butyl ether, bis (4-dimethylaminophenyl) ketone, benzyl methoxy ketal, 2-chlorothioxanthone, o-methyl benzoate, benzyl dimethyl ketal, methyl benzoyl formate, etc. Although it is not limited to these.

It is preferable that 0.1 to 10 parts by mass of the component (D) is added to 100 parts by mass of the component (A), and particularly preferably 0.1 to 5 parts by mass. When the amount of the component (D) is more than 0.1 parts by mass, the surface curability is improved to eliminate the tack, and when the amount of the component (D) is less than 5 parts by mass, storage stability can be maintained.

The component (E) that can be used in the present invention is an amorphous silica powder with a surface of no treatment and a specific surface area of 100 to 500 m ² / g. The specific surface area can be measured by the BET specific surface area or the like. Here, that the surface is not treated means that the amorphous silica powder has silanol such as ≡Si-OH remaining on the surface, and the silanol is not chemically modified. On the contrary, the surface treatment means a state in which hexamethyldisilazane or octylsilane is reacted with silanol to chemically modify the silanol.

Specific examples of the component (E) include AEROSIL 300 (non-treated and specific surface area 300 m ² / g), 200 (untreated and specific surface area 200 m ² / g), 130 (non-treated and ratio) surface area and is 130m ² / g), although the specific surface area in the CAB-O-SIL M5 (untreated CABOT Corporation and the like 200m ² / g), but is not limited thereto.

The component (E) is preferably added in an amount of 0.1 to 30 parts by mass, particularly preferably 1 to 20 parts by mass, per 100 parts by mass of the component (A). When the component (E) is more than 0.1 parts by mass, thixotropy is exhibited, and when the component (E) is less than 30 parts by mass, the handling property is good.

In the present invention, fillers such as inorganic fillers and organic fillers can be appropriately added in addition to the component (E). By adding a filler, not only viscosity and thixotropy, but also curability and toughness can be adjusted. The inorganic filler includes, but is not limited to, alumina, silica and the like. On the other hand, examples of the organic filler include styrene filler, rubber filler, core-shell acrylic filler and the like, but are not limited thereto.

Radical thermal curing agent, photosensitizer, silane coupling agent, titanium coupling agent, leveling agent, polymerization inhibitor, aging in order to adjust the properties of the present invention to the extent that the physical properties of the cured product are not impaired. Additives such as an inhibitor, a plasticizer, a thixotropic agent, a filler, and a solvent may be blended.

The illuminance of the LED irradiation device using the LED as a light source is generally 30 to 900 mW / cm ² , and in some cases, 20 to 300 mW / cm ² . As compared with an irradiation apparatus using a high pressure mercury lamp, in the LED irradiation apparatus, the tendency of the photo-curing property of the curable resin to be lowered is caused due to the low illuminance. However, according to the present invention, even in the case of a low illuminance or a constant integrated light quantity, it has a light curing property sufficiently compatible with the LED irradiation apparatus.

EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Hereinafter, the photocurable composition is also simply referred to as a composition.

[Examples 1 to 10, Comparative Examples 1 to 12]
The following ingredients were prepared to prepare the composition.
Component (A): Urethane-modified acrylic oligomer having a (meth) acrylic oligomer / polycarbonate skeleton (UN-9000PEP manufactured by Negami Industrial Co., Ltd.)
Component (B): Component (B-1) and Component (B-2) (Meth) Acrylic Monomer (B-1) Component: Aliphatic Hydrocarbon Group-Containing (Meth) Acrylic Monomer Isononyl Acrylate (INAA) Osaka Organic Chemical Industry Co., Ltd.)
・ Lauryl acrylate (LA Osaka Organic Chemical Industry Co., Ltd.)
Component (B'-1): (meth) acrylic monomer having a hydrocarbon group other than the component (B-1)-isobornyl acrylate (light acrylate IB-XA, manufactured by Kyoeisha Chemical Co., Ltd.)
Component (B-2): (Meth) acrylic monomer having a hydroxyl group, 4-hydroxybutyl acrylate (4-HBA Osaka Organic Chemical Industry Co., Ltd.)
2-Hydroxyethyl methacrylate (HEMA Nippon Catalyst Co., Ltd.)
Component (B'-2): (meth) acrylic monomer having a polar group other than the component (B-2) tetrahydrofurfuryl acrylate (manufactured by THFA Osaka Organic Chemical Industry Co., Ltd.)
Other monomers: (Meth) acrylic monomers other than the (B-1) component and the (B-2) component · Mixture of ethylene oxide modified di and triacrylate with isocyanuric acid (Alonix M313 manufactured by Toagosei Co., Ltd.)
Component (C): polythiol compound pentaerythritol tetrakis (3-mercaptobutyrate) (Kalens MT PE-1 manufactured by Showa Denko KK)
-Pentaerythritol tetrakis (3-mercapto propionate) (manufactured by PEMP SC Organic Chemical Co., Ltd.)
Component (D): photo initiator / 1-hydroxycyclohexyl phenyl ketone (manufactured by Suncure 84 Chemark Chemical Co., Ltd.)
(E) Component: Amorphous silica powder with no surface treatment and a specific surface area of 100 to 500 m ² / g, Amorphous silica powder with a specific surface area of 300 m ² / g (AEROSIL 300 manufactured by Nippon Aerosil Co., Ltd.)
· Amorphous silica powder without treatment and having a specific surface area of 200 m ² / g (AEROSIL 200 manufactured by Nippon Aerosil Co., Ltd.)
· Amorphous silica powder without treatment and having a specific surface area of 130 m ² / g (AEROSIL 130 manufactured by Nippon Aerosil Co., Ltd.)
· Amorphous silica powder without treatment and having a specific surface area of 200 m ² / g (CAB-O-SIL M5 manufactured by CABOT)
Component (E '): Amorphous silica powder other than the component (E) · Amorphous silica powder without treatment and having a specific surface area of 50 m ² / g (AEROSIL 50 manufactured by Nippon Aerosil Co., Ltd.)
· Amorphous silica powder with a specific surface area of 140 m ² / g by hexamethyldisilazane treatment (AEROSIL RX200 manufactured by Nippon Aerosil Co., Ltd.)
· Amorphous silica powder with a specific surface area of 150 m ² / g by octylsilane treatment (AEROSIL R805)

The components (A), (B) and (C) were weighed in a stirring vessel and stirred for 30 minutes while vacuum degassing. Thereafter, the component (E) (or the component (E ')) was weighed into a stirring vessel and stirred for 1 hour while vacuum degassing. Finally, the component (D) was weighed and charged into a stirring kettle and stirred for 15 minutes. The detailed preparation amounts are shown in Table 1 and all numerical values are expressed in parts by mass. Further, “total of (meth) acrylic monomers” in Table 1 indicates the total mass parts of all (meth) acrylic monomers, and “the ratio of (B-1) component or (B′-1)” and “(B)” -2) The ratio of the component or (B'-2) "indicates the mass% of each component with respect to the total mass part of the (meth) acrylic monomer.

[Viscosity measurement]
The composition of 0.5 cc is collected and discharged into a measuring cup. The viscosity was measured with an EHD viscometer (manufactured by Toki Sangyo Co., Ltd.) under the following conditions. The result is referred to as “viscosity (Pa · s)”. From the viewpoint of workability such as extrudability from a syringe etc., 30 Pa · s or less is preferable.
Measurement conditions Corn rotor: 3 ° x R14
Rotation speed: 20 rpm
Measurement time: 3 minutes Measurement temperature: 25 ° C (controlled by thermostat)

[Thicking test]
5 g of the composition is weighed on a glass plate, and when the glass plate is inclined at 45 ° under an atmosphere of 25 ° C., the state of the composition is judged to be “thixophilic” by the following evaluation criteria. The thixotropy is preferably “o” from the viewpoint of maintaining the shape with high accuracy after being discharged from a syringe or the like.
Evaluation criteria ○: composition does not flow ×: composition flows

[Thick film hardenability check]
While the composition is placed in a glass container to a depth of 6 mm, it is irradiated with 100 mW for 30 seconds with an LED irradiator (365 nm) to form a sheet-like cured product. The uncured material is wiped off, the thickness is measured with a vernier caliper, and the value is taken as "thick film hardenability (mm)". At this time, when the thick film curability is 5 mm or more, it is described as "5 mm or more". In order to make the cured state of the cured product uniform, it is preferable that the thick film curability be 3 mm or more.

[Hardness measurement]
While setting the thickness of the composition to 2 mm, the sheet is irradiated with 100 mW for 30 seconds with an LED irradiator (365 nm) to form a sheet-like cured product. The cured product is stacked in three layers to make a 6 mm cured product. While keeping the pressing surface of the A-type durometer (hardness meter) parallel to the sheet-like cured product, the sample is pressed closely with a force of 10 N without causing an impact, thereby bringing the pressing surface into contact with the sample. At the time of measurement, read the maximum value, and let the maximum value be "hardness (no unit)". The details conform to JIS K 6253. When used as a sealing agent for on-site formation, in order to maintain the elasticity of the cured product, it is preferably A60 or less, more preferably A30 or less.

[Total light transmittance measurement]
The composition is irradiated with 100 mW for 30 seconds with an LED irradiator (365 nm) to form a sheet-like cured product having a thickness of 1 mm. The measurement is performed using a haze meter NDH2000 manufactured by Nippon Denshoku Kogyo Co., Ltd. The details conform to JIS K 7361. The total light transmittance is represented by all the light amounts obtained by the haze meter, and is referred to as "total light transmittance (%)" according to the following evaluation criteria. If the total light transmittance is 90% or more, it is not discolored, which is preferable.
Evaluation criteria ○: 90% or more ×: less than 90%

[Haze measurement]
The composition is irradiated with 100 mW for 30 seconds with an LED irradiator (365 nm) to form a sheet-like cured product having a thickness of 1 mm. The measurement is performed using a haze meter NDH2000 manufactured by Nippon Denshoku Kogyo Co., Ltd. The details conform to JIS K 7136. It is obtained from the equation of haze (%) = Td / Tt × 100 (Td: diffuse transmittance, Tt: total light transmittance), and the haze is an index related to the transparency of the sheet-like cured product, and the turbidity (cloudiness) And represents "haze (%)" according to the following evaluation criteria. If it is 5% or less as haze, it does not become cloudy and is preferable.
Evaluation criteria ○: 5% or less ×: greater than 5%

[Humidity resistance test]
After measuring the total light transmittance and the haze of the sheet-like cured product immediately after curing, the cured product is allowed to stand for 300 hours under an atmosphere of 60 ° C. × 95% RH. After taking out and leaving at 25 ° C. for 1 hour, the total light transmittance measurement and the haze are measured. It is preferable that both the total light transmittance and the haze be “o” after the initial stage and after the moisture resistance test.

Examples 1 to 10 contain 70% by mass or less of the component (B-1) with respect to the entire component (B) and 30% by mass or more of the component (B-2), and the surface is untreated and the specific surface area is It is a composition containing 100 to 500 m ² / g of amorphous silica powder, and has good properties of viscosity, thixotropy, hardness, total light transmittance and haze after initial and moisture resistance test. On the other hand, in Comparative Examples 1 to 5, the performance of the total light transmittance and the haze after the moisture resistance test is lowered. Comparative Example 6 has no problem in the moisture resistance test but does not exhibit thixotropy. Comparative Examples 7 to 9 have a problem with haze at an early stage. Comparative Example 10 is not suitable because the proportion of the components (B-1) and (B-2) in the component (B) is not suitable, and the comparative example 11 uses the component (B'-2). The performance of the total light transmittance and the haze after the test is reduced. Since Comparative Example 12 uses IB-XA, the hardness is high and elasticity is not imparted to the cured product.

The cured product after light irradiation of the present invention is soft and has high haze measurement and high moisture resistance, as well as high total light transmittance measurement of the cured product even when exposed to a high temperature and high humidity atmosphere. Moreover, since the thixotropy is high when the viscosity of the photocurable composition is low, it is suitable for workability. As an application which can utilize the said characteristic effectively, it can be used for Cure-in-place Gasket (CIPG) as an application of a sealing agent, and since it has thick film curability, it can also be used as a potting agent. Since it has moisture resistance, the field of displays such as liquid crystal and organic EL can be mentioned as usable fields.

Claims (7)

A photocurable composition containing (A) to (E) components and containing 30 to 70% by mass of the component (B-1) with respect to the whole component (B) and 30 to 60% by mass of the component (B-2) Composition.
(A) component: (meth) acrylic oligomer (except for the (B) component)
Component (B): (meth) acrylic monomer having a molecular weight of 1,000 or less and containing (B-1) and (B-2) components (B-1) component: aliphatic hydrocarbon group having no cyclic structure (Meth) acrylic monomer having (B-2) component: (meth) acrylic monomer having a hydroxyl group (C) component: polythiol compound (D) component: a photoinitiator (E) component: the surface is untreated and the specific surface area is 100 to 500 m ² / g amorphous silica powder The photocurable composition according to claim 1, wherein the component (B-1) is a (meth) acrylic monomer having an aliphatic hydrocarbon group of the following structure:
(Here, R is hydrogen or a methyl group, and n is an integer of 1 to 20.) The photocurable composition according to any one of claims 1 and 2, wherein the component (B-2) is a (meth) acrylic monomer having a hydroxyl group of the following structure.
(Here, R is hydrogen or a methyl group, m shows the integer of 3-10.) The photocurable composition according to any one of claims 1 to 3, wherein the component (B) contains a (meth) acrylic monomer having an isocyanurate skeleton. The component (B) is contained in an amount of 50 to 150 parts by mass with respect to 100 parts by mass of the component (A).
The photocurable composition as described in any of the above. The photocurable composition according to any one of claims 1 to 5, wherein the component (C) comprises 5 to 25 parts by mass with respect to 100 parts by mass of the component (A). The sealing agent containing the photocurable composition in any one of Claims 1-6.