JP2014148643A - Photocurable elastomer composition, sealing material, and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable elastomer composition that is excellent in, when it is cured, flexibility, water vapor barrier property and compression set, as well as, when it is curing, excellent in adhesiveness, and a sealing material using the composition, and a device having the sealing material.SOLUTION: The photocurable elastomer composition is characterized to comprise: (A) a first polymer having at least two (meth)acryloyl groups in the molecule; (B) a second polymer having one (meth)acryloyl group in the molecule; (C) a monomer having a photocurable functional group in the molecule; and (D) a photopolymerization initiator.

Description

  The present invention relates to a photocurable elastomer composition, a sealing material, and an apparatus.

  As a material of the hard coating material which is the mainstream of the sealing material, a composition containing a bisphenol A type epoxy (meth) acrylate as a main component is common. Since this composition has a strong intermolecular force and is three-dimensionally dense, it has excellent gas / water vapor barrier properties, but the cured product is very hard. Therefore, it cannot be used for sealing materials that require flexibility. Examples of the sealing material that is required to be flexible include materials that can be bent such as a sealing material or packing related to a flexible display. In addition, especially when used for a flexible display, the sealing material needs to have a property of returning to its original state when bent, and in order to ensure this property, it is necessary to reduce compression set. Furthermore, the elastomer composition used as the sealing material needs to have a property of not being peeled off from the grounding base material when bent, and in order to ensure this property, it is necessary to improve adhesiveness.

  Conventionally, an elastomer composition (for example, see Patent Document 1) containing a reactive polymer having a (meth) acryloyl group at a terminal, a (meth) acrylic acid ester monomer, and a radical photopolymerization initiator is sealed. It is being considered as a material.

  However, a photocurable elastomer composition that can maintain a certain level of flexibility, water vapor barrier property, compression set, and adhesiveness at the time of curing has not yet been developed. Its development was highly desired.

JP 2007-39587 A

Then, the objective of this invention is providing the photocurable elastomer composition excellent in the softness | flexibility at the time of hardening, water vapor | steam barrier property, and compression set, and the adhesiveness at the time of hardening.
Moreover, the objective of this invention is providing the sealing material excellent in the softness | flexibility, water vapor | steam barrier property, adhesiveness, and compression set.
Furthermore, the objective of this invention is providing the apparatus using the said sealing material excellent in a softness | flexibility, water vapor | steam barrier property, adhesiveness, and compression set.

The photocurable elastomer composition of the present invention comprises (A) a first polymer having at least two (meth) acryloyl groups in the molecule, and (B) a second polymer having one (meth) acryloyl group in the molecule. And (C) a monomer having a photocurable functional group in the molecule, and (D) a photopolymerization initiator.
According to this structure, it is excellent in the softness | flexibility at the time of hardening, water vapor | steam barrier property, and compression set, and the adhesiveness at the time of hardening.

In this specification, “light” in “photocurability” and “photopolymerization” means ultraviolet rays; visible rays; charged particle rays such as α rays, β rays, electron rays, electromagnetic waves such as γ rays, and high Ionizing radiation containing energetic particles, and particularly preferably ultraviolet rays.
In the present specification, the “number average molecular weight” means a number average molecular weight represented by a standard polystyrene equivalent value measured by a gel permeation chromatography (GPC) method unless otherwise specified.
In the present specification, “(meth) acryloyl” means at least one of acryloyl and methacryloyl, an acryloyl group means (CH ₂ ═CHCO—), and a methacryloyl group has (CH ₂ ═C ( CH ₃ ) CO—).
In the present specification, the “main skeleton” means a main skeleton (a skeleton having the largest proportion in the skeleton) that forms the main chain of the polymer. The main skeleton can be determined using, for example, NMR measurement.
In the present specification, the “butadiene skeleton” means (i) — [CH ₂ —CH═CH—CH ₂ ] —unit (cis-1,4 bond), (ii) — [CH ₂ —CH═CH—CH. ₂ ] -unit (trans-1,4 bond), and (iii)-[CH ₂ —CH (CH═CH ₂ )]-unit (1,2 bond). “Isobutylene skeleton” means a skeleton composed of — [CH ₂ —C (CH ₃ ) ₂ ] — units, and “Isoprene skeleton” means (i) — [CH ₂ —C (CH ₃ ) = CH-CH _2] - units (cis-1,4 _{bond), (ii) - [CH} 2 -C (CH 3) = CH-CH 2] - units (trans-1,4 bonds), (iii _{) - [CH 2 -C (CH} 3) (CH = CH 2)] - units (1,2-bond), and (iv) - [CH ₂ - _{(C (CH 3) = CH} 2)] - it means a skeleton composed of at least one selected from the group consisting of units (3,4 bonds).
In the present specification, “cyclic hydrocarbon” includes not only aliphatic cyclic hydrocarbons but also aromatic cyclic hydrocarbons.
In the present specification, the “sealing material” is a concept including a sealing material, a sealing material, a gasket, and packing. Further, in this specification, unless otherwise specified, the sealing material, the gasket, and the packing include both a fixing seal (static seal) and a motion seal.

  In the photocurable elastomer composition of the present invention, the content of the monomer is 40% by mass to 80% by mass with respect to the total amount of the first polymer, the second polymer, and the monomer. preferable. According to this structure, low viscosity is possible and the softness | flexibility at the time of making it harden | cure can be ensured.

  In the photocurable elastomer composition of the present invention, a mass ratio (first polymer: second polymer) between the content of the first polymer and the content of the second polymer is from 20:80 to It is preferably 80:20. According to this configuration, it is possible to achieve both a high water vapor barrier and a good compression set when cured.

  In the photocurable elastomer composition of the present invention, the content of the photopolymerization initiator is 0.1% by mass to 10% by mass with respect to the total amount of the first polymer, the second polymer, and the monomer. % Is preferred. According to this configuration, curing is sufficient.

  In the photocurable elastomer composition of the present invention, the first polymer preferably has (meth) acryloyl groups at both ends. According to this structure, the compression set at the time of hardening can be improved.

  In the photocurable elastomer composition of the present invention, the second polymer preferably has a (meth) acryloyl group at one end. According to this structure, adhesiveness can be improved more.

  In the photocurable elastomer composition of the present invention, the main skeleton of the first polymer is preferably a hydrogenated butadiene skeleton. According to this structure, the water vapor | steam barrier property at the time of making it harden | cure can be improved more, and sealing performance and the heat resistance at the time of making it harden | cure can be improved.

  In the photocurable elastomer composition of the present invention, the main skeleton of the second polymer is preferably a hydrogenated butadiene skeleton. According to this structure, the water vapor | steam barrier property at the time of making it harden | cure can be improved more, and sealing performance and the heat resistance at the time of making it harden | cure can be improved.

  In the photocurable elastomer composition of the present invention, the photocurable functional group in the monomer is preferably a (meth) acryloyl group. According to this configuration, it can be easily procured.

  In the photocurable elastomer composition of the present invention, the monomer is preferably isobornyl acrylate. According to this structure, the water vapor | steam barrier property after hardening can be improved more. Among the monomers having a cyclic hydrocarbon skeleton, the isobornyl skeleton is particularly effective in improving the water vapor barrier property after curing, and unlike other cyclic hydrocarbon skeletons, the increase in hardness is not extreme, so that it is easy to use.

  The photocurable elastomer composition of the present invention is preferably used for a sealing material.

  The sealing material of the present invention is characterized in that the photocurable elastomer composition of the present invention is used at least in part. According to this configuration, the sealing material is excellent in flexibility, water vapor barrier property, adhesiveness, and compression set. .

  The apparatus of the present invention is characterized by having at least a part of the sealing material of the present invention, and according to this configuration, both sealing performance and water vapor barrier performance can be achieved.

ADVANTAGE OF THE INVENTION According to this invention, the photocurable elastomer composition excellent in the softness | flexibility at the time of hardening, water vapor | steam barrier property, and compression set, and the adhesiveness at the time of hardening can be provided.
Moreover, according to this invention, the sealing material excellent in the softness | flexibility, water vapor | steam barrier property, adhesiveness, and compression set can be provided.
Furthermore, according to the present invention, it is possible to provide an apparatus that can achieve both sealing properties and water vapor barrier properties.

(Photocurable elastomer composition)
The photocurable elastomer composition of the present invention comprises at least (A) a first polymer, (B) a second polymer, (C) a monomer, and (D) a photopolymerization initiator. In addition, if necessary, it further comprises other components.

<(A) First polymer>
(A) The first polymer is a polymer having at least two (meth) acryloyl groups in the molecule and has a function of maintaining the sealing property. (A) The first polymer is not particularly limited as long as it has at least two (meth) acryloyl groups in the molecule, and can be appropriately selected according to the purpose. May be). Specific examples of the (A) first polymer are not particularly limited and may be appropriately selected depending on the intended purpose. For example, (1) urethane acrylate polymer (for example, UV-2000 manufactured by Nippon Synthetic Chemical Co., Ltd.) , Weight average molecular weight 13,000, having two (meth) acryloyl groups at both ends), (2) methacryl-modified isoprene rubber (for example, trade name UC-102 manufactured by Kuraray Co., Ltd., number average molecular weight 17,000, (Having two (meth) acryloyl groups in the side chain), (3) hydrogenated polybutadiene diacrylate (for example, (i) trade name CN9014 manufactured by Sartomer Co., Ltd. (number average molecular weight 6,500, both (meth) acryloyl groups) (Ii) Trade name TEAI-1000 (number average molecular weight 2,000, (meth) acryloyl made by Nippon Soda Co., Ltd.) (4) methacryl-modified isoprene rubber (for example, trade name UC-203 manufactured by Kuraray, number average molecular weight 27,000, (meth) acryloyl group in the side chain) And the main skeleton is non-hydrogenated), etc. These may be used alone or in combination of two or more.

  The main skeleton of the (A) first polymer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include conjugated diene skeletons such as urethane skeleton, butadiene skeleton and isoprene skeleton, isobutylene skeleton, and the like. Is mentioned. Among these, a butadiene skeleton is preferable in terms of a water vapor barrier and a sealing property when cured. Further, the main skeleton is preferably hydrogenated, whereby the water vapor barrier property upon curing can be further improved, and the heat resistance upon curing can be improved. Furthermore, it is preferable that the main skeleton is a hydrogenated butadiene skeleton, which can further improve the water vapor barrier property when cured, can further improve the heat resistance, and is easily available. .

  The number of (meth) acryloyl groups in the molecule of the (A) first polymer is not particularly limited as long as it is 2 or more, and can be appropriately selected according to the purpose. When there are two or more (meth) acryloyl groups in the molecule of the (A) first polymer, a network structure can be formed, and the compression set upon curing can be further reduced. Thereby, high sealing performance is obtained.

  There is no restriction | limiting in particular as a position of the (meth) acryloyl group in the molecule | numerator of said (A) 1st polymer, According to the objective, it can select suitably, A polymer both terminal may be sufficient, A polymer side chain However, both ends of the polymer are free branches (parts not involved in cross-linking), and it is possible to prevent the compression set from becoming large when cured due to increased viscosity. Is preferable.

  The number average molecular weight of the (A) first polymer is not particularly limited and may be appropriately selected depending on the intended purpose. It is preferably 1,000 to 40,000, and preferably 2,000 to 35,000. More preferred. When the number average molecular weight of the (A) first polymer is 1,000 or more, it is preferable from the viewpoint of flexibility when cured, and when it is 40,000 or less, the viscosity is low and easy to handle. preferable. Moreover, it is more advantageous in the point of the softness | flexibility at the time of making it harden | cure and the ease of handling that the number average molecular weight of said (A) 1st polymer exists in the said more preferable range.

  There is no restriction | limiting in particular as content of said (A) 1st polymer, Although what is necessary is just to adjust suitably according to a use, a use condition, the performance requested | required, etc., (A) 1st polymer, mentioned later (B) 10 mass%-50 mass% are more preferable with respect to the total amount of the 2nd polymer and the (C) monomer mentioned later. Content of said (A) 1st polymer is 10 mass% or more with respect to the total amount of said (A) 1st polymer, (B) 2nd polymer mentioned later, and (C) monomer mentioned later. And it is preferable in terms of flexibility when cured, and is preferably 50% by mass or less in terms of low viscosity.

<(B) Second polymer>
(B) A 2nd polymer is a polymer which has one (meth) acryloyl group in a molecule | numerator, and has a function which makes adhesiveness high. (B) The second polymer is not particularly limited as long as it has only one (meth) acryloyl group in the molecule and can be appropriately selected according to the purpose. May be). Specific examples of the (B) second polymer are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polybutadiene acrylate (for example, trade name L1253 manufactured by Kuraray Co., Ltd., (meth) acryloyl). And a group having one group at one end, and the main skeleton is hydrogenated).

  The main skeleton of the (B) second polymer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a conjugated diene skeleton such as a urethane skeleton, a butadiene skeleton, and an isoprene skeleton, and an isobutylene skeleton. Is mentioned. Among these, a butadiene skeleton is preferable in terms of a water vapor barrier and a sealing property when cured. Moreover, it is preferable that the main skeleton is hydrogenated, whereby the water vapor barrier property when cured can be further improved, and the heat resistance can be improved. Further, the main skeleton is preferably a hydrogenated butadiene skeleton, whereby the water vapor barrier property when cured can be further improved, and the heat resistance can be further improved.

  The position of one (meth) acryloyl group in the molecule of the (B) second polymer is not particularly limited and may be appropriately selected depending on the purpose. Although it may be a polymer side chain, the polymer piece end is preferred in that it can increase viscosity and improve adhesion.

  The number average molecular weight of the (B) second polymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1,000 to 40,000, more preferably 2,000 to 35,000. More preferred. When the number average molecular weight of the (B) second polymer is 1,000 or more, it is preferable from the viewpoint of flexibility when cured, and when it is 40,000 or less, the viscosity is low and easy to handle. preferable. Moreover, it is more advantageous in the point of the softness | flexibility at the time of making it harden | cure and the ease of handling that the number average molecular weight of said (B) 2nd polymer is in the said more preferable range.

  There is no restriction | limiting in particular as content of said (B) 2nd polymer, Although what is necessary is just to adjust suitably according to a use, a use condition, the performance requested | required, etc., the said (A) 1st polymer, said ( B) 10 mass%-40 mass% are preferable with respect to the 2nd polymer and the total amount of the (C) monomer mentioned later. The content of the (B) second polymer is 10% by mass or more based on the total amount of the (A) first polymer, the (B) second polymer, and the (C) monomer described later. In terms of flexibility when cured, it is preferably 40% by mass or less in terms of low viscosity.

<Mass ratio of (A) content of first polymer and content of (B) second polymer ((A) first polymer: (B) second polymer)>
The mass ratio ((A) first polymer: (B) second polymer) of the content of the (A) first polymer and the content of the (B) second polymer is not particularly limited. However, 20:80 to 80:20 is preferable, 30:70 to 70:30 is more preferable, and 40:60 to 60:40 is preferable. Is particularly preferred. When the mass ratio ((A) first polymer: (B) second polymer) is 20 or more and 80 or less, compression set upon curing can be improved, and 80 or less: When it is 20 or more, flexibility when cured can be imparted. On the other hand, when the mass ratio ((A) first polymer: (B) second polymer) is within the more preferable range or the particularly preferable range, the compression set when cured is This is advantageous in that both flexibility can be achieved.

<(C) Monomer>
The monomer (C) has a function of imparting photocurability (moldability) to the photocurable elastomer composition of the present invention. The monomer (C) is not particularly limited as long as it has a photocurable functional group in the molecule, and can be appropriately selected according to the purpose. Examples of the photocurable functional group include a (meth) acryloyl group, an epoxy group, a vinyl group, a maleimide group, and a vinylidene group. These may be used individually by 1 type and may use 2 or more types together. Among these, a (meth) acryloyl group is preferable in terms of abundant molecular skeleton that can be easily procured. There is no restriction | limiting in particular as a monomer which has the said (meth) acryloyl group in a molecule | numerator, According to the objective, it can select suitably, For example, phenoxyethyl acrylate, (meth) acryloyl morpholine, cyclohexyl (meth) acrylate , Dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, dimethylaminoethyl (meth) acrylate, dipropylene glycol mono ( (Meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxylated phenyl (meth) acrylate, ethyl (meth) acrylate, isoamyl (meth) acrylate, isobornyl (meth) ) Acrylate, isobutyl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (meth) acrylate, isostearyl (meth) acrylate, isomyristyl (meth) acrylate, lauroxypolyethylene glycol (meth) acrylate, lauryl (meth) acrylate, Methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (For example, 2-ethylhexyl-diglycol acrylate), n-octadecyl (meth) acrylate, (meth) acrylic acid Esters of polyhydric alcohols, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these monomers having a (meth) acryloyl group in the molecule, a monomer having a cyclic hydrocarbon skeleton (for example, isobornyl (meth) acrylate) is preferable in terms of a water vapor barrier when cured.

  The content of the (C) monomer is not particularly limited and may be appropriately adjusted according to the use, use state, required performance, etc., but the (A) first polymer, the (B) first 40 mass%-80 mass% are preferable with respect to the total amount of the polymer of 2 and the said (C) monomer, 40 mass%-70 mass% are more preferable, 40 mass%-60 mass% are especially preferable. When the content of the (C) monomer is less than 40% by mass, the viscosity is increased, and when it is more than 80% by mass, compression set is deteriorated. On the other hand, when the content of the monomer (C) is within a preferable range, a more preferable range, or a particularly preferable range, it can be controlled as a suitable viscosity region in processing to a sealing material. It is advantageous.

<(D) Photopolymerization initiator>
(D) The photopolymerization initiator has a function of initiating or promoting photopolymerization or curing of the photocurable component.
The (D) photopolymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include benzoin alkyl ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether and benzoin isopropyl ether. Acetophenone-based photopolymerization initiators such as 2,2-diethoxyacetophenone, 4′-phenoxy-2,2-dichloroacetophenone; 2-hydroxy-2-methylpropiophenone, 4′-isopropyl-2-hydroxy-2 -Propiophenone photopolymerization initiators such as methylpropiophenone and 4'-dodecyl-2-hydroxy-2-methylpropiophenone; benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2 -Hydroxyethoxy) -phenyl] -2-hydro Ci-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-hydroxy-1- [4- [4- (2-hydroxy-2 -Methyl-propionyl) -benzyl] phenyl] -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1 -Alkylphenone photopolymerization initiators such as butanone; anthraquinone photopolymerization initiators such as 2-ethylanthraquinone and 2-chloroanthraquinone; 2,4,6-trimethylbenzoyl Acylphosphine oxide photopolymerization initiators such as phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; bis (η5-2, Titanocene photopolymerization initiators such as 4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium; α-alkylaminoketone photopolymerization Initiators; oxime ester photopolymerization initiators; oxyphenyl acetate photopolymerization initiators; cationic photopolymerization initiators. These may be used individually by 1 type and may use 2 or more types together. Among these, 2,4,6-trimethylbenzoylphenylphosphine oxide is preferable. Examples of the (D) photopolymerization initiator include benzophenone / amine photopolymerization initiators, Michler ketone / benzophenone photopolymerization initiators, and thioxanthone / amine photopolymerization initiators. Further, as the (D) photopolymerization initiator, those other than those described above, for example, those used in conventionally known photocurable compositions such as those described in Patent Document 1 are appropriately selected and used. be able to.

What is necessary is just to adjust suitably content of the said (D) photoinitiator according to the kind, content, etc. of a photocurable component in a photocurable elastomer composition.
There is no restriction | limiting in particular as content of said (D) photoinitiator, Although it can select suitably according to the objective, For example, the said photocurable component (For example, said (A) 1st polymer, said ( B) 0.1 parts by weight to 10 parts by weight is preferable, 0.5 parts by weight to 5 parts by weight is more preferable, and 0.5 parts by weight with respect to 100 parts by weight in total of the second polymer and the monomer (C). Part by mass to 3 parts by mass are particularly preferred. Moreover, you may use a well-known photosensitizer together with the said (D) photoinitiator.

<Other ingredients>
The photocurable elastomer composition of the present invention is an inorganic filler (thixotropic agent); an organic thixotropic agent (thixotropic agent); a coupling agent as necessary without departing from the spirit of the present invention. Antioxidants (anti-aging agents); light stabilizers; carbodiimides; fatty acids such as stearic acid; fatty acid metal salts such as calcium stearate; fatty acid amides such as stearic acid amide; fatty acid esters; polyolefin wax, paraffin wax, etc. Release agents; softeners such as process oils; colorants; leveling agents; solvents;

<Method for Preparing Photocurable Elastomer Composition>
There is no restriction | limiting in particular in the preparation method of the photocurable elastomer composition of this invention, A well-known method can be used. For example, the (A) first polymer, (B) second polymer, (C) monomer, (D) photopolymerization initiator, and the other components are mixed into a kneader (for example, a single screw extruder, two It can be prepared by kneading using a screw extruder, planetary mixer, twin screw mixer, high shear mixer or the like.

<Viscosity of photocurable elastomer composition>
There is no restriction | limiting in particular as a viscosity of the photocurable elastomer composition of this invention, Although it can select suitably according to the objective, 2 Pa * s or less is preferable. If the viscosity is more than 2 Pa · s, it is not suitable for thin film coating. In addition, as a photocurable elastomer composition for display sealing materials, there are many cases of thin film application | coating (about 100 micrometers thickness), and low viscosity is preferable.

<Adhesiveness of photocurable elastomer composition>
There is no restriction | limiting in particular as adhesiveness of the photocurable elastomer composition of this invention, Although it can select suitably according to the objective, It is preferable that it is 1 N / 15mm or more in the peeling test of an adhesive surface.
If it is less than 1 N / 15 mm, there is a risk of peeling from the adherend surface when bent.

(Seal material)
The sealing material of the present invention can be produced by using at least a part of the photocurable elastomer composition of the present invention. That is, the sealing material of the present invention is a sealing material containing at least part of a cured product obtained by irradiating the photocurable elastomer composition of the present invention with light such as ultraviolet rays. The sealing material of the present invention uses at least part of the photocurable elastomer composition of the present invention, so that flexibility (low hardness), water vapor barrier property (low moisture permeability), adhesiveness, and compression set Can be kept at a certain level.

  The flexibility of the sealing material of the present invention can be appropriately adjusted according to the use, but the flexibility is preferably a Shore D hardness described later of 60 or less, more preferably 50 or less, It is especially preferable that it is 40 or less. In addition, when the sealing material of this invention is used for a flexible display, for example, it is preferable that a softness | flexibility is large (a hardness is low), and when Shore D hardness is more than 60, there exists a possibility that it may be cracked when it bends. is there.

The water vapor barrier property of the sealing material of the present invention can be appropriately adjusted according to the application, but the moisture permeability described later is 20 (g / m) due to the influence on the internal parts and the corrosion resistance to the metal electrode. ² · day) or less.

  Since the sealing material of the present invention needs to return to some extent when it is bent, it is preferable that the compression set value described later is 40 (%) or less. Thereby, a high sealing performance is obtained.

  The sealing material of the present invention is, for example, a sealing material for various display devices (particularly flexible displays) such as a liquid crystal display device, an organic EL display, an electronic paper, and a plasma display; a sealing material for solar cells; a desktop type, a notebook type, a tablet Seals for various electronic parts such as computers, mobile phones, cameras, etc .; HDD (hard disk drive) gaskets; Ink tank seals; Automobile parts, water purifiers, air purifiers, agitators, speakers, pumps It can be used for applications such as sealing materials such as vibration-proofing devices, waterproofing devices, dampers, construction materials such as civil engineering and buildings; packings such as O-rings. Among these, since the sealing material of the present invention is excellent in flexibility, water vapor barrier property, adhesiveness, and compression set, it can be suitably used for flexible displays. Although the thickness of a sealing material can be suitably adjusted with a use, it is about 0.01 mm-1 mm normally.

<Method for producing member with sealing material>
A member with a sealing material can be produced by applying the photocurable elastomer composition of the present invention to an adherend and curing it by irradiation with light. As an adherend, it can select suitably according to a use, for example. The adherend may be an inorganic material or a resin. The adherend is not particularly limited, and a conventionally known adherend can be used. For example, cold rolled steel sheet, galvanized steel sheet, aluminum / zinc alloy plated steel sheet, stainless steel sheet, aluminum plate, aluminum alloy plate, magnesium plate, magnesium alloy plate and other metals, inorganic deposition such as alumina, silica, ITO, etc. Etc., films of PET, PEN, PP, PE, PC and the like.

  The method for applying the photocurable elastomer composition of the present invention to an adherend is not particularly limited, and a conventionally known method can be appropriately selected and used. Application is, for example, adjusting the temperature of the photocurable elastomer composition as necessary, adjusting to a desired viscosity, gravure coat, roll coat, spin coat, reverse coat, bar coat, screen coat, blade coat, air It can be performed by knife coating, dipping, dispensing, or the like. The photocurable elastomer composition of the present invention is applied to an adherend, molded as necessary, and then irradiated with light to cure the photocurable elastomer composition to obtain a member with a sealing material. .

Light for curing the photocurable elastomer composition of the present invention includes ultraviolet rays; visible rays; charged particles such as α rays, β rays, electron rays, electromagnetic waves such as γ rays, and ionization including high energy particles. What is necessary is just to select suitably from radiation. Such light is preferably ultraviolet rays from the viewpoints of operability, productivity, economy, and the like. As the ultraviolet ray source, a conventionally known one can be used, and examples thereof include a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, and a microwave excimer lamp. The atmosphere for irradiating ultraviolet rays may be an air atmosphere, an inert gas atmosphere such as nitrogen gas or carbon dioxide gas, or an atmosphere with a reduced oxygen concentration. The irradiation atmosphere temperature may be adjusted as appropriate, and can usually be 10 ° C to 200 ° C. The irradiation time may be adjusted as appropriate, and is usually preferably 10 seconds to 60 minutes. The integrated light quantity may be adjusted as appropriate, and is usually preferably 1,000 mJ / cm ^{2 to} 20,000 mJ / cm ² .

<Method for forming flexible display sealing material and solar cell sealing material>
For example, the photo-curable elastomer composition of the present invention is filled in a dedicated syringe, extruded by air (air) or machine, discharged from a thin needle tip, and applied to a cover plate (adhered body). By irradiating light, such as ultraviolet rays, to the photocurable elastomer composition, the photocurable elastomer composition is cured and molded. Moreover, it can shape | mold also by methods other than the shaping | molding method mentioned above (for example, spin coat, die coat, gravure printing, silk screen, etc.).

(apparatus)
The apparatus of the present invention is characterized by having at least a part of the sealing material of the present invention. The apparatus of the present invention has both the sealing property and the water vapor barrier property by having at least a part of the sealing material of the present invention. Examples of the device of the present invention include various display devices (particularly flexible displays) such as liquid crystal display devices, organic EL displays, electronic paper, and plasma displays; solar cells; various computers such as desktop types, notebook types, and tablet types; Mobile phone; Camera; HDD; Ink tank; Automobile parts; Water purifier; Air purifier; Stirrer; Speaker; Pump; Vibration isolator; Waterproof device; Can do. Among these, since the device of the present invention can achieve both sealing properties and water vapor barrier properties, it can be suitably used for flexible displays and solar cells.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

  Each component was mix | blended with the prescription shown in Table 1-Table 3 (The value in each component represents a mass part), and the photocurable elastomer composition was prepared. Then, the viscosity (workability), hardness (flexibility), adhesiveness, moisture permeability (water vapor barrier property), and compression set were measured and evaluated by the following methods. The results are shown in Tables 1 to 3.

<Processability (viscosity)>
The viscosity of the photocurable elastomer composition was measured at 25 ° C. with a viscometer. In addition, since it examined by the material which does not have thixotropy (thixo) property, it can be regarded as Newtonian fluid almost, and the rotation speed was set arbitrarily. The smaller the viscosity, the better, and 2 (Pa · s) or less is preferable.

<Flexibility (hardness)>
A photocurable elastomer composition was formed to a thickness of about 2 mm, and this was cured by light irradiation using a metal halide lamp to obtain a sheet. The light irradiation was performed under conditions of an illuminance of about 150 mW / cm ² and an integrated light amount of about 9,000 mJ / cm ^{2 in} an air atmosphere. The hardness (Shore D) of this sheet was measured with a hardness meter (manufactured by Kobunshi Keiki). A specimen having a thickness of about 6 mm obtained by laminating three sheets having a thickness of about 2 mm was used. In addition, the smaller one is better, and 60 or less is preferable.

<Adhesiveness>
The adhesion of the photocurable elastomer composition to the PET film (trade name: Lumirror, manufactured by Toray Industries, Inc.) was measured by a 90 ° peel test under the condition of 50 mm / min measurement. In addition, the larger one is better, and 1N or more is preferable.

<Compression set>
In accordance with JIS K 6262, 5 sheets of 2 mm-thick sheets cut into 2 cm squares were stacked to form a measurement sample, and the compression set after 30 minutes at a test temperature of 70 ° C. was measured. . The compression set is preferably as small as possible and is preferably 40% or less.

<Water vapor barrier property (moisture permeability)>
The sheet having a thickness of about 1 mm was measured under the condition of 60 ° C. and relative humidity of 90% in accordance with JIS Z 0208 using a moisture permeable cup of Method A described in JIS L 1099. The moisture permeability is preferably as small as possible and is preferably 20 [g / m ² · day] or less.

In Tables 1 to 3, * 1 to * 16 indicate the following.
* 1 Hydrogenated acrylic modified butadiene rubber: CN-9014 manufactured by Sartomer (number average molecular weight 6,500, having (meth) acryloyl groups at both ends, the main skeleton is hydrogenated)
* 2 Methacrylic modified isoprene rubber: UC-102 manufactured by Kuraray Co., Ltd. (number average molecular weight 17,000, having two (meth) acryloyl groups in the side chain)
* 3 Hydrogenated acrylic modified butadiene rubber: TEAI-1000 manufactured by Nippon Soda Co., Ltd. (number average molecular weight 2,000, (meth) acryloyl groups at both ends, the main skeleton is hydrogenated)
* 4 Methacryl-modified isoprene rubber: (trade name UC-203, manufactured by Kuraray, number average molecular weight 27,000, three (meth) acryloyl groups in the side chain, main skeleton is non-hydrogenated)
* 5 Urethane acrylate polymer: trade name UV-2000B manufactured by Nippon Synthetic Chemical Co., Ltd. (weight average molecular weight 13,000, having (meth) acryloyl groups at both ends)
* 6 Hydrogenated acrylic modified butadiene rubber: Product name L1253 manufactured by Kuraray Co., Ltd. (weight average molecular weight 7,000, (meth) acryloyl group at one end, main skeleton is hydrogenated)
* 10 IBXA (isobornyl acrylate, molecular weight 208, monofunctional acrylate monomer) manufactured by Osaka Organic Chemical Industry Co., Ltd.
* 11 Light acrylate L-A (lauryl acrylate, molecular weight 240, monofunctional acrylate monomer) manufactured by Kyoeisha Chemical Co., Ltd.
* 12 Funkrill FA-513AS (dicyclopentanyl acrylate, molecular weight 206, monofunctional acrylate monomer) manufactured by Hitachi Chemical Co., Ltd.
* 13 Kyoeisha Chemical Co., Ltd. light ester 1,4BG (1,4-butanediol dimethacrylate (without cyclic hydrocarbon skeleton), molecular weight 226, bifunctional acrylate monomer)
* 14 2,4,6-Trimethylbenzoylphenylphosphine oxide (Lucirin TPO manufactured by BASF)
* 15 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by BASF)
* 16 2- (Dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (Irgacure 379 manufactured by BASF)

  From Tables 1 to 3, (A) a first polymer having at least two (meth) acryloyl groups in the molecule, and (B) a second polymer having one (meth) acryloyl group in the molecule, Examples (1) to (23) containing (C) a monomer having a photocurable functional group in the molecule and (D) a photopolymerization initiator are more flexible (low hardness) than Comparative Examples 1 to 9, It can be seen that the water vapor barrier property, adhesiveness, and compression set can be maintained at a certain level and are excellent.

Claims (13)

(A) a first polymer having at least two (meth) acryloyl groups in the molecule;
(B) a second polymer having one (meth) acryloyl group in the molecule;
(C) a monomer having a photocurable functional group in the molecule;
(D) A photopolymerization initiator, and a photocurable elastomer composition comprising the photopolymerization initiator.   2. The photocuring according to claim 1, wherein a content of the monomer is 40% by mass to 80% by mass with respect to a total amount of the first polymer, the second polymer, and the monomer. Elastomeric composition.   The mass ratio of the content of the first polymer to the content of the second polymer (first polymer: second polymer) is 20:80 to 80:20. Item 2. The photocurable elastomer composition according to Item 1.   The content of the photopolymerization initiator is 0.1% by mass to 10% by mass with respect to the total amount of the first polymer, the second polymer, and the monomer. The photocurable elastomer composition described in 1.   The photocurable elastomer composition according to claim 1, wherein the first polymer has (meth) acryloyl groups at both ends.   The photocurable elastomer composition according to claim 1, wherein the second polymer has a (meth) acryloyl group at one end.   The photocurable elastomer composition according to claim 1, wherein the first polymer has a hydrogenated butadiene skeleton as a main skeleton.   The photocurable elastomer composition according to claim 1, wherein the second polymer has a hydrogenated butadiene skeleton as a main skeleton.   2. The photocurable elastomer composition according to claim 1, wherein the monomer has a (meth) acryloyl group as the photocurable functional group.   The photocurable elastomer composition according to claim 9, wherein the monomer is isobornyl acrylate.   The photocurable elastomer composition according to claim 1, wherein the photocurable elastomer composition is used for a sealing material.   A sealing material comprising the photocurable elastomer composition according to any one of claims 1 to 11 at least partially.   An apparatus comprising at least a part of the sealing material according to claim 12.