JP2019014888A - Resin composition, sheet, laminate using the same, image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition capable of realizing good adhesive strength, holding power, high transparency and water vapor barrier property. SOLUTION: The isobutylene-based polymer (A) and an acrylate-based polymer (B) containing a monofunctional (meth) acrylate having a long-chain alkyl chain having 10 or more carbon atoms as a main component are included, and shearing at a frequency of 1 Hz. The resin composition has a maximum point of at least one loss tangent in the range of -20 to 20 ° C., and is a dispersion of the acrylate-based polymer (B) having a diameter of 1 μm or more when observed with a transmission electron microscope. We propose a phaseless resin composition. [Selection diagram] None

Description

  The present invention relates to a resin composition having adhesive strength, holding power, transparency, and water vapor barrier properties, and further relates to a sheet using the resin composition, a laminate using the sheet, and an image display device.

In recent years, curved or foldable display devices using organic light emitting diodes (OLEDs) and quantum dots (QDs) have been developed and are being widely commercialized.
Such a display device has a structure in which a plurality of film-like constituent members are bonded with a transparent optical adhesive (also referred to as “OCA”) sheet. However, conventionally used acrylic OCA sheets have various problems due to lack of moisture-proof performance, and problems such as corrosion and migration of metal electrodes, and new material-based OCA sheets have been demanded.

An example of a polymer material that can solve the above problem is polyisobutylene.
Polyisobutylene has a feature that the water vapor barrier property is particularly high as a general-purpose soft resin, but the cohesive force is too small to be applied to a resin composition. was there.

  As one of the methods for improving such polyisobutylene having low cohesive strength, a method for improving cohesive strength by polymerizing (meth) acrylate after mixing a monomer such as (meth) acrylate with polyisobutylene. It has been known.

  For example, Non-Patent Document 1 discloses a composition having a semi-IPN structure composed of a network of polyisobutylene and polycyclohexyl methacrylate (PCHMA) which is a monofunctional (meth) acrylate. It is disclosed that the flow is suppressed and the water vapor barrier property inherent in polyisobutylene is also provided.

  Patent Document 1 discloses a pressure-sensitive adhesive composition containing a sealing resin such as polyisobutylene, a polyfunctional (meth) acrylate, and a specific silane compound, and a pressure-sensitive adhesive film obtained from this pressure-sensitive adhesive composition is excellent. It has been described that it has water vapor barrier properties and transparency.

JP-T-2006-527377

B. Davion et al. / Polymer, 51, (2010), 5323-5331

The pressure-sensitive adhesive sheet composed of polyisobutylene and polyfunctional acrylate disclosed in Patent Document 1 can have an excellent water vapor barrier property, but by itself, the glass transition temperature is too low to obtain a sufficient pressure-sensitive adhesive force. Had no problem.
As a method of increasing the glass transition temperature, a method of blending a large amount of a tackifier such as petroleum resin is known, and even in Example 1 of Patent Document 1, about 25% by mass of a hydrogenated DCPD-based tackifier is present. It has been added. However, when such a large amount of tackifier is blended, the glass transition temperature can be increased, but the holding power as a property capable of maintaining the adhesion state for a long period of time is lowered.

  In addition, the polyisobutylene / DCPA composition containing tricyclodecane dimethanol diacrylate (DCPA) exemplified in the example of Patent Document 1 has a refractive index of a cured product extremely close to the refractive index of polyisobutylene. Therefore, the transparency of the composition can be maintained to some extent. However, when such a polyisobutylene / DCPA composition is observed with a transmission electron microscope (TEM), the compatibility of polyisobutylene and DCPA is not good, and a DCPA cured product having a size of 1 μm or more is dispersed. Therefore, there is a possibility that a problem occurs in holding power and transparency.

  In the system shown in Non-Patent Document 1, when the content ratio of polyisobutylene is large, the properties of polyisobutylene are remarkably exhibited, and it is difficult to obtain a pressure-sensitive adhesive sheet having sufficient adhesion and holding power. .

  The present invention is intended to provide a new resin composition that has good adhesion, good holding power, excellent transparency, and can realize excellent water vapor barrier properties.

  The present invention includes an isobutylene polymer (A) and an acrylate polymer (B) mainly composed of a monofunctional (meth) acrylate having a long-chain alkyl chain having 10 or more carbon atoms, and shearing at a frequency of 1 Hz. A resin composition having at least one maximum point of loss tangent (tan δ) in the range of −20 to 20 ° C., when the resin composition is observed with a transmission electron microscope (magnification: 1000 times to 5000 times) ), And proposes a resin composition characterized in that no lump having a maximum diameter of 1 μm or more is observed.

  The resin composition proposed by the present invention includes an isobutylene polymer (A) and a specific acrylate polymer (B), and at least one maximum point of loss tangent is in the range of -20 to 20 ° C. When the composition is observed with a transmission electron microscope, no lump having a maximum diameter of 1 μm or more is observed, that is, the isobutylene polymer (A) and the acrylate polymer (B) are uniformly dispersed. Therefore, it can be excellent in adhesiveness, holding power, transparency, and water vapor barrier properties. Therefore, for example, by forming a sheet from the resin composition and using the sheet as a constituent member of an image display device or the like, it is possible to contribute to thinning of the image display device or the like.

It is the graph which showed the loss tangent (tan-delta) of each resin composition obtained in Examples 1-3 and Comparative Examples 1-2. It is the photograph which observed the resin composition obtained in Example 1 with the transmission electron microscope (1000 times). It is the photograph which observed the resin composition obtained in Example 1 with the transmission electron microscope (5000 times). It is the photograph which observed the resin composition obtained in Example 3 with the transmission electron microscope (2000 times). It is the photograph which observed the resin composition obtained in Example 3 with the transmission electron microscope (5000 times). It is the photograph which observed the resin composition obtained by the comparative example 1 with the transmission electron microscope (1000 times). It is the photograph which observed the resin composition obtained by the comparative example 2 with the transmission electron microscope (1000 times).

  The present invention will be described in detail below. However, the contents of the present invention are not limited to the embodiments described below.

<This resin composition>
A resin composition (referred to as “the present resin composition”) according to an example of an embodiment of the present invention has an isobutylene polymer (A) (hereinafter sometimes referred to as “component A”) and a carbon number of 10. A resin composition comprising an acrylate polymer (B) (hereinafter sometimes referred to as “B component”) mainly composed of a monofunctional (meth) acrylate having a long alkyl chain. .

  Here, the “main component” means the resin component contained in the acrylate polymer (B) in the largest amount, in other words, the resin component having the highest mass ratio. The main component preferably accounts for 60% by mass or more of the entire acrylate polymer (B), more preferably 65% by mass or more, and most preferably 70% by mass or more.

In this resin composition, a semi-IPN (interpenetrating polymer network) structure is formed between the isobutylene polymer (A) and the acrylate polymer (B) to achieve both water vapor barrier properties and transparency. It is preferable.
Moreover, this resin composition selects and contains the monofunctional (meth) acrylate which has a C10 or more long-chain alkyl chain as a main component of (meth) acrylate, and is isobutylene type polymer (A ) And the acrylate polymer (B) are further entangled, and as a result, a resin composition and sheet having excellent adhesion and holding power can be obtained.
In addition, the present resin composition, which selectively contains a long-chain alkyl acrylate having 10 or more carbon atoms, greatly affects the higher order structure of the resin composition, and is extremely good as a two-component resin composition. Can exhibit high transparency.

(composition)
In this resin composition, it is preferable that the acrylate polymer (B) is contained in a proportion of 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the isobutylene polymer (A).
If content of an acrylate polymer (B) is 5 mass parts or more, the cohesion force of this resin composition can be improved effectively. Further, when the content of the acrylate polymer (B) is 100 parts by mass or less, the dispersion diameter of the component (B) in the sheet can be reduced, the transparency is exhibited, and the transparency is exhibited. it can.
From this viewpoint, the content ratio of the acrylate polymer (B) is preferably 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the isobutylene polymer (A). More preferably, it is 10 parts by mass or less, or 80 parts by mass or less.

(State and form)
If this resin composition is a composition containing an isobutylene polymer (A) and an acrylate polymer (B), its state and form are arbitrary.
For example, it may be liquid, gel, solid, or other state.

  This resin composition can also be made into various forms, such as a sheet form, rod shape, hollow shape, and other shapes. Among these, for example, an unstretched sheet used as an adhesive sheet can be given.

When this resin composition exhibits a sheet shape, the thickness is not particularly limited. For example, it is 0.01 mm or more, more preferably 0.03 mm or more, still more preferably 0.05 mm or more. On the other hand, the upper limit is preferably 1 mm or less, more preferably 0.7 mm or less, and still more preferably 0.5 mm or less.
If the thickness is 0.01 mm or more, the handleability is good, and if the thickness is 1 mm or less, it can contribute to the thinning of the laminate.

(Dispersibility)
When this resin composition is observed with a transmission electron microscope (magnification: 1000 times to 5000 times), it is preferable that no lump having a maximum diameter of 1 μm or more is observed.
The fact that a lump having a maximum diameter of 1 μm or more is not observed in this way means that the isobutylene polymer (A) and the acrylate polymer (B) are highly compatible with each other. As a product, both water vapor barrier properties and transparency can be achieved.
“A lump with a maximum diameter of 1 μm or more is not observed” means that after the resin composition is dyed with ruthenium tetroxide or the like, the resin composition is cut with a cryomicrotome or the like under freezing, and the cross section is shown as a transmission electron. When observed at a magnification of 1000 to 5000 times with a microscope (TEM), each of the three sections was observed at 10 random locations, and no lump with a maximum diameter of 1 μm or more was observed in any field of view. means.
As described above, when the content of the acrylate polymer (B) is smaller than that of the isobutylene polymer (A), the above “lumps having a maximum diameter of 1 μm or more” are lumps composed of the acrylate polymer (B). .

  As described above, the fact that no lump having a maximum diameter of 1 μm or more is observed means that the isobutylene polymer (A) and the acrylate polymer (B) are highly compatible. As shown in FIGS. 2 to 5, the resin composition has a structure in which the isobutylene polymer (A) and the acrylate polymer (B) are uniformly dispersed with each other, or has a sea-island structure.

(Tan δ)
In the resin composition, it is preferable that at least one maximum point of loss tangent (tan δ) in shearing at a frequency of 1 Hz is in a range of −20 to 20 ° C.
When the maximum point of the loss tangent (tan δ) is in the range of −20 ° C. to 20 ° C., a resin composition having good adhesiveness and holding power can be obtained.
By selecting an acrylate having a long-chain alkyl chain having 10 or more carbon atoms as the main component of the acrylate polymer (B), and selecting the type of isobutylene polymer and the quantitative ratio thereof, -20 ° C to 20 ° C Within this range, the maximum point of loss tangent (tan δ) can be adjusted. Moreover, the maximum point of loss tangent can also be adjusted in the range of -20-20 degreeC also by adding the tackifier (C) mentioned later. However, it is not limited to such a method.

  Moreover, this resin composition has a maximum value of loss tangent (tan δ) at a shear frequency of 1 Hz in the range of −20 to 20 ° C., and a maximum value of loss tangent at a frequency of 1 Hz shear is 0.50 or more. It is more preferable than the point of ensuring adhesiveness. Among these, 0.55 or more, further 0.60 or more is even more preferable.

  The loss tangent (tan δ) at 100 ° C. of the resin composition is preferably 0.60 or less, and more preferably 0.50 or less. When the loss tangent (tan δ) at 100 ° C. is 0.60 or less, it is possible to develop a more sufficient high temperature holding force.

(Glass-transition temperature)
The resin composition preferably has a single glass transition temperature (Tg).
It is rare for a multicomponent system consisting of at least the component (A) and the component (B) to have a single glass transition temperature (Tg) like a single material. However, in this resin composition, since the compatibility of the component (A) and the component (B) is good, the glass transition temperature (Tg) can be made single. When the glass transition temperature is single, the transparency of the resin composition can be increased.
Here, the “glass transition temperature” refers to the temperature at which the main dispersion peak of loss tangent (tan δ) appears. Therefore, when only one maximum point of loss tangent (tan δ) in shearing at a frequency of 1 Hz is observed, it can be considered that the glass transition temperature (Tg) is single.

(Total light transmittance and haze)
The total light transmittance when the thickness of the resin composition is molded to 100 μm is preferably 85% or more, more preferably 88% or more, and further preferably 90% or more.
The resin composition preferably has a haze of 10.0 or less, preferably 2.0 or less, particularly 1.0 or less, when the thickness is molded to 100 μm. . When the haze is 10.0 or less, a sheet that can be suitably used for a display device can be formed.
Depending on the application, the sheet can be used for a display device.

The resin composition preferably has a haze of 2.0 or less when the thickness is molded to 50 μm. When the haze is 2.0 or less, a sheet that can be suitably used for a display device can be formed.
From this viewpoint, the haze when the thickness of the resin composition is molded to 50 μm is preferably 2.0 or less, more preferably 1.5 or less, and particularly 1.2 or less. More preferably.

The resin composition preferably has a haze of 1.0 or less when the thickness is molded to 25 μm. When the haze is 1.0 or less, a sheet that can be suitably used for a display device can be formed.
From this viewpoint, the haze when the thickness of the resin composition is molded to 25 μm is preferably 1.0 or less, more preferably 0.9 or less, and particularly 0.8 or less. More preferably.

(Water vapor transmission rate)
The resin composition is required to have a water vapor transmission rate as low as possible in order to suppress deterioration of the light emitting element due to water and improve the lifetime of the display device.
From this viewpoint, the water vapor transmission rate in an environment of a temperature of 40 ° C. and a relative humidity of 90% RH in terms of 100 μm thickness (when the thickness is 100 μm) of the resin composition is 20 g / m ² · 24 h or less. It is more preferably 15 g / m ² · 24 h or less, particularly preferably 10 g / m ² · 24 h or less. The lower limit is not particularly limited, but is generally 0.5 g / m ² · 24 h or more.
When the water vapor transmission rate is 20 g / m ² · 24 h or less, water vapor from the outside is prevented / suppressed from reaching the object to be sealed, and the water vapor barrier property is improved.
In order to make the water vapor transmission rate in the above range, it is preferable that the polyisobutylene resin (A) is contained in an appropriate amount.

Here, the water vapor transmission rate can be measured according to JIS K7129B.
For example, when the thickness is A μm and the water vapor transmission rate is Bg / (m ² · day), the water vapor transmission rate in terms of 100 μm thickness is obtained by applying the formula B × A / 100. be able to.

(HSP distance)
This resin composition has a Hansen solubility parameter (HSP) distance of 5.0 or less between the isobutylene polymer (A) and the monofunctional (meth) acrylate as the main component of the acrylate polymer (B). It is preferably 4.5 or less, more preferably 3.8 or less.
If the HSP distance between the component (A) and the monofunctional (methacrylate) component is 5.0 or less, the compatibility of the isobutylene polymer (A) and the acrylate polymer (B) becomes good, and the bleed It is possible to suppress deterioration of transparency due to out and increase in dispersion diameter.

Here, the “hansen solubility parameter (HSP)” is an index representing the solubility of how much a certain substance is soluble in another certain substance.
HSP is a three-dimensional space in which the solubility parameter introduced by Hildebrand is divided into three components: a dispersion term δD, a polar term δP, and a hydrogen bond term δH. The dispersion term δD indicates the effect due to the dispersion force, the polar term δP indicates the effect due to the dipole force, the hydrogen bond term δH indicates the effect due to the hydrogen bond force,
δD: Energy derived from intermolecular dispersion force δP: Energy derived from intermolecular polar force δH: Energy derived from intermolecular hydrogen bonding force (Here, each unit is MPa ^0.5 .)

The definition and calculation of HSP are described in the following documents.
Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007).

  The dispersion term reflects the van der Waals force, the polar term reflects the dipole moment, and the hydrogen bond term reflects the action of water, alcohol, etc. Those having similar vectors by HSP can be determined to have high solubility, and the similarity of vectors can be determined by the distance of the Hansen solubility parameter (HSP distance). In addition, Hansen's solubility parameter can be an index not only for determining solubility, but also for determining how much a certain substance is likely to exist in another certain substance, that is, how good the dispersibility is.

  In the present invention, HSP [δD, δP, δH] can be easily estimated from its chemical structure by using, for example, computer software Hansen Solubility Parameters in Practice (HSPiP). Specifically, it is obtained from the chemical structure by the Y-MB method, which is implemented in HSPiP. When the chemical structure is unknown, the chemical structure is obtained by the sphere method implemented in HSPiP from the result of the dissolution test using a plurality of solvents.

HSP distance (Ra) is, for example HSP solute (acrylate polymer in the present invention (B)) to the HSP _{(δD 1, δP 1, δH} 1) and the solvent (polyisobutylene resin in the present invention (A)) the _{(δD 2, δP 2, δH} 2) when formed into a can be calculated by the following equation.
HSP distance (Ra) = {4 × ( δD 1 -δD 2) 2 + (δP 1 -δP 2) 2 + (δH 1 -δH 2) 2} 0.5

(Isobutylene polymer (A))
The isobutylene polymer (A) constituting the resin composition is a polymer having an isobutylene skeleton in the main chain or side chain, and has a structural unit represented by the following formula (1).

  The isobutylene polymer (A) has a function of improving the water vapor barrier property of the resin composition.

  As isobutylene polymer (A), polyisobutylene which is a homopolymer of isobutylene, a copolymer of isobutylene and isoprene, a copolymer of isobutylene and n-butene, a copolymer of isobutylene and butadiene, and these copolymers And halogenated butyl rubber obtained by bromination or chlorination. These polymers can be used singly or in combination of two or more.

  Among these, polyisobutylene and an isobutylene / isoprene copolymer are preferable from the viewpoint of improving the durability and weather resistance of the resin composition and reducing the water vapor transmission rate.

The isobutylene / isoprene copolymer has a repeating unit derived from isobutylene [—CH ₂ —C (CH ₃ ) ₂ —] and a repeating unit derived from isoprene [—CH ₂ —C (CH ₃ ) ═CH— in the molecule. It is a synthetic rubber having CH ₂ —].
The content of repeating units derived from isoprene in the isobutylene / isoprene copolymer is usually from 0.1 to 99 mol%, preferably from 0.5 to 50 mol%, more preferably from all repeating units. 1 to 10 mol%.
If the repeating unit derived from isoprene in the isobutylene / isoprene copolymer is in the above range, a resin composition excellent in moisture resistance is obtained, which is preferable.

  The type of the isobutylene / isoprene copolymer is not particularly limited, and examples thereof include a regenerated isobutylene / isoprene copolymer and a synthetic isobutylene / isoprene copolymer. Among these, a synthetic isobutylene / isoprene copolymer is preferable.

Examples of the method for synthesizing the isobutylene polymer include a method of polymerizing a monomer component such as isobutylene in the presence of a Lewis acid catalyst such as aluminum chloride or boron trifluoride.
Moreover, a commercial item can also be used as an isobutylene polymer (A). Examples of commercially available products include Vistanex (manufactured by Exxon Chemical Co.), Hycar (manufactured by Goodrich), Opanol (manufactured by BASF), Tetrax (manufactured by JX), and the like.

The weight average molecular weight (Mw) of the isobutylene polymer (A) is preferably 50,000 to 2,000,000 g / mol, more preferably 100,000 g / mol or more, or 1,500,000 g / mol or less. Of these, 1,000,000 g / mol or less is more preferable.
When the weight average molecular weight (Mw) is an isobutylene polymer (A) having a molecular weight of 100,000 or more, the fluidity of the resin composition becomes appropriate, and the shape is easily retained after being formed into a sheet. Moreover, a uniform resin composition is easy to be obtained because it is an isobutylene polymer (A) whose weight average molecular weight (Mw) is 2,000,000 or less.
Here, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography using tetrahydrofuran as a solvent (GPC analysis) and converted to standard polystyrene.

Moreover, the isobutylene polymer (A) which comprises this resin composition can also be used in combination of 2 or more types of isobutylene polymers (A) from which average molecular weight differs.
A combination of an isobutylene polymer having a weight average molecular weight of less than 100,000 g / mol and an isobutylene polymer having a weight average molecular weight of 100,000 g / mol or more can be used as an isobutylene polymer having a bimodal molecular weight distribution. Good.
Thus, even if the original is a separate raw material, the weight average molecular weight of the isobutylene polymer (A) as a whole is 50,000 to 2,000,000 g / mol, more preferably 100,000 to 1,500. 1,000 g / mol, more preferably 100,000 to 1,000,000.

  Examples of commercially available products having a weight average molecular weight of less than 100,000 g / mol include trade name: Tetrax (JX Energy), trade name: Hymor (JX Energy), and a weight average molecular weight of 100,000 g / mol. Examples of the above-mentioned commercially available products include trade name: Opanol (BASF).

(Acrylate polymer (B))
The acrylate polymer (B) is a polymer mainly composed of a monofunctional (meth) acrylate having a long alkyl chain having 10 or more carbon atoms. (Meth) acrylate means at least one of acrylate and methacrylate.

  The monofunctional (meth) acrylate having a long-chain alkyl chain having 10 or more carbon atoms is a (meth) acrylate having one (meth) acryloyloxy group and having a long-chain alkyl chain having 10 or more carbon atoms. The structure of the monofunctional aliphatic acrylate is shown in the following formula (2).

In the above formula (2), R represents a long-chain alkyl group having 10 or more carbon atoms.
In the above formula, R ′ is hydrogen (H) or a methyl group (CH ₃ ).

The long-chain alkyl group (R) having 10 or more carbon atoms refers to an alkyl group having 10 or more carbon atoms in the main chain. Examples thereof include a decyl group (C ₁₀ ), an undecyl group (C ₁₁ ), and a dodecyl group (C _12), tridecyl _{(C 13),} tetradecyl _{(C 14),} pentadecyl _{(C 15),} hexadecyl _{(C 16),} heptadecyl _{(C 17),} octadecyl _{(C 18),} nonadecyl groups _{(C 19} And the like. The upper limit of the carbon number of the main chain is not particularly defined, but if it is 20 or less, preferably 18 or less, crystallization by monofunctional aliphatic (meth) acrylates is unlikely to occur, so low haze and high total light transmission. It becomes easy to express transparency by rate.

  If the main chain has 10 or more carbon atoms, the long-chain alkyl group (R) may have a branched alkyl group. In general, a branched alkyl group is less likely to be crystallized in a normal temperature region than a straight chain alkyl group, and transparency is easily exhibited.

  Also, using two or more different long-chain alkyl groups in combination is effective in suppressing crystallization and improving transparency.

As described above, the HSP of the monofunctional (meth) acrylate is preferably located at a position where the HSP distance to the isobutylene polymer (A) is 5.0 or less, and located at a position 4.5 or less. More preferred.
Specific examples of the monofunctional (meth) acrylate having an HSP distance of 5.0 or less from the isobutylene polymer (A) include isostearyl (meth) acrylate, isohexadecyl (meth) acrylate, Examples include stearyl (meth) acrylate, hexadecyl (meth) acrylate, isotetradecyl (meth) acrylate, tetradecyl (meth) acrylate, isododecyl (meth) acrylate, dodecyl (meth) acrylate, isodecyl (meth) acrylate, and the like.

  Only one type of aliphatic mono (meth) acrylate may be used, or several types may be used in combination.

  The content of the monofunctional (meth) acrylate component in the resin composition (100% by mass) is preferably 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass. That's it. The creep resistance of this resin composition can be improved because it is 5 mass% or more. On the other hand, the upper limit is preferably 40% by mass or less, preferably 38% by mass or less, and more preferably 35% by mass or less. The water vapor barrier property of this resin composition can be improved because it is 40 mass% or less.

  Moreover, it is preferable that the content rate with respect to the whole said acrylate polymer (B) component of monofunctional aliphatic (meth) acrylate is 60-90 mass%, and it is 70 mass% or more or 90 mass% or less especially. It is more preferable. By setting it as the said range, cohesion force can also be raised, maintaining transparency.

(Multifunctional (meth) acrylate)
In the present resin composition, it is preferable to add a small amount of polyfunctional (meth) acrylate in order to adjust the network of the component (B).

The polyfunctional (meth) acrylate is a (meth) acrylate having two or more (meth) acryloyloxy groups and having at least (meth) acryloyloxy groups bonded via a hydrocarbon group.
As an example of the polyfunctional (meth) acrylate, the structure of the bifunctional aliphatic (meth) acrylate is shown in the following formula (3).

In the above formula, R is hydrogen (H) or a methyl group (CH ₃ ).
X is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group.

The content of the polyfunctional (meth) acrylate is preferably 0.5% by mass or more and less than 10% by mass with respect to the resin composition, and more preferably 1% by mass or more or less than 9% by mass. Among them, the content is more preferably 2% by mass or more or less than 8% by mass.
By adding 0.5 mass% or more of polyfunctional (meth) acrylate content, it is possible to adjust the network of component (B), while reducing it to less than 10 mass% reduces bleedout. In addition, transparency can be enhanced in combination with the monofunctional aliphatic (meth) acrylate.

  From the same viewpoint, it is preferable to add polyfunctional (meth) acrylate at a ratio of 10 to 45 parts by mass with respect to 100 parts by mass of monofunctional (meth) acrylate having a long alkyl chain having 10 or more carbon atoms. Among these, it is more preferable to add at a ratio of 15 parts by mass or more or 40 parts by mass or less, and among them, 20 parts by mass or more or 35 parts by mass or less.

The HSP of the polyfunctional (meth) acrylate is preferably at a position where the HSP distance from the isobutylene polymer (A) is 9.0 or less, and more preferably at a position of 8.0 or less.
By setting the HSP distance in the above range, troubles related to transparency and adhesiveness such as bleeding out can be suppressed.

  In the polyfunctional (meth) acrylate, the aliphatic hydrocarbon group or the alicyclic hydrocarbon group (X) is preferably a hydrocarbon group that does not contain multiple bonds from the viewpoint of long-term stability of the sheet.

  Examples of the polyfunctional (meth) acrylate used in the resin composition include 1.9-nonanediol di (meth) acrylate, 1.10-decanediol di (meth) acrylate, and hydrogenated polybutadiene (meth) acrylate. Di (meth) acrylate having a linear alkyl group; di (meth) acrylate having an alicyclic skeleton such as tricyclodecanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, and the like Can do. However, it is not limited to these.

  Moreover, polyfunctional urethane acrylate can also be used as polyfunctional (meth) acrylate. From the viewpoint of compatibility with the component (A), a urethane acrylate having an aliphatic polymer such as polybutadiene in the skeleton is preferable. Examples of commercially available products include trade name: CN9014 NS (Sartomer), trade name: BAC-45 (manufactured by Osaka Organic Chemical Co., Ltd., polybutadiene-terminated diacrylate), and the like.

  The polyfunctional (meth) acrylate is not limited to bifunctional (meth) acrylate, and polyfunctional (meth) acrylate having 3, 4, or more than 4 (meth) acryloyl groups may be used. However, bifunctional (meth) acrylate is more preferable from the viewpoint of long-term stability of the sheet and easy availability of acrylate.

  In addition, polyfunctional (meth) acrylate may use only 1 type, or may use several types together.

(Tackifier (C))
This resin composition may further contain a tackifier (C) in order to enhance the adhesiveness.
Generally, the isobutylene resin composition contains a large amount of a tackifier. However, the content of the tackifier is preferably less than 10% by mass in order to prevent problems such as a decrease in high-temperature cohesion due to the addition of the tackifier and yellowing. By setting it as this range, it can be set as this resin composition excellent in high temperature cohesion force.

The tackifier (C) may be any compound or mixture of compounds that can enhance the adhesiveness of the resin composition.
Examples of the tackifier (C) include an aliphatic hydrocarbon tackifier represented by a terpene tackifier, an aromatic hydrocarbon tackifier represented by a phenol tackifier, and a rosin tack. An alicyclic hydrocarbon tackifier represented by an imparting agent, a tackifier composed of these hydrocarbon copolymers, an epoxy tackifier, a polyamide tackifier, a ketone tackifier, and These hydrogenated substances are exemplified. Among these, from the viewpoint of compatibility, an aliphatic hydrocarbon tackifier, an aromatic hydrocarbon tackifier, an alicyclic hydrocarbon tackifier, and a tack made of these hydrocarbon copolymers An imparting agent is preferred. Particularly preferred are aliphatic hydrocarbon tackifiers.
Moreover, these tackifiers can be used singly or in combination of two or more.

(Other)
The present resin composition may contain a softening agent.
The softening agent can adjust the viscosity of the composition in order to improve processability, for example.

Examples of softening agents that can be used include aromatic hydrocarbons, paraffinic and naphthenic petroleum hydrocarbons, liquid polybutene, and liquid rubbers such as hydrogenated liquid polyisoprene or derivatives thereof, petroleum jelly, and petroleum Asphalt can be mentioned. However, it is not limited to these.
In embodiments that use a softener, a single softener or a combination of softeners can be used.
In the present resin composition, the liquid polyisobutylene resin is treated as an isobutylene polymer (A).

The present resin composition may contain an adhesion promoter.
By using the adhesion-imparting agent, adhesion with various base materials can be improved, and firing at the interface can be suppressed.
Examples of the adhesion-imparting agent that can be used include acrylamide compounds such as acrylamide, diethyl acrylamide, dimethylaminopropyl acrylamide, isopropyl acrylamide, acryloyl morpholine, and cyclic trimethylolpropane formal acrylate. However, they do not decline.
In embodiments using an adhesion promoter, one type of adhesion promoter or a combination of multiple adhesion promoters can be used.

In addition, this resin composition is obtained by adding a curing accelerator, filler, coupling agent, ultraviolet absorber, ultraviolet stabilizer, antioxidant, stabilizer, or some combination thereof to the curable composition. Also good.
The amount of these additives is typically preferably selected so as not to adversely affect the curing of the resin composition or to adversely affect the physical properties of the curable composition.

<Manufacturing method>
Hereinafter, the manufacturing method of this resin composition is demonstrated. However, the following description is an example of a method for producing the resin composition, and the resin composition is not limited to those produced by the production method.

  This resin composition prepares the resin composition containing the said (A) component and a monofunctional (meth) acrylate component, for example, The said (B) component using the said monofunctional (meth) acrylate component This resin composition can be prepared by curing the resin composition to cure the resin composition and appropriately processing as necessary. However, it is not limited to such a manufacturing method.

For example, the component (A), the monofunctional (meth) acrylate component, the polymerization initiator and the optional component are mixed into a kneading machine (for example, a single-screw extruder, a twin-screw extruder, a planetary mixer, a twin-screw) capable of adjusting the temperature. The curable composition which is a precursor of this resin composition can be prepared by kneading | mixing using a mixer, a pressure kneader, etc.).
When mixing various raw material resins to obtain a curable composition, various additives such as silane coupling agents and antioxidants may be blended with the resin in advance and then supplied to the extruder. All materials may be supplied after being melt-mixed, or a master batch in which only the additive is previously concentrated in the resin may be prepared and supplied.

In order to impart curability, the resin composition preferably contains a polymerization initiator as described above.
The polymerization initiator is not particularly limited as long as it is a polymerization initiator that can be used for the polymerization reaction of acrylate. For example, those activated by heat and those activated by active energy rays can be used. Any of those that generate radicals to cause radical reaction and those that generate cations and anions to cause addition reaction can be used.
Preferred polymerization initiators are photopolymerization initiators, and generally the selection of the photopolymerization initiator depends at least in part on the specific components used in the curable composition and the desired cure rate.

Examples of the photopolymerization initiator include acetophenone, benzoin, benzophenone, benzoyl compound, anthraquinone, thioxanthone, and phosphine oxide such as phenyl and diphenylphosphine oxide, ketone, and acridine.
Specifically, LUCIRIN (BASF) available as trade names DAROCUR (Ciba Specialty Chemicals), IRGACURE (Ciba Specialty Chemicals) and ethyl-2,4,6-trimethylbenzoyldiphenylphosphinates available as LUCIRIN TPO A photoinitiator can be mentioned.

  As the photopolymerization initiator, one having an excitation wavelength region of 400 nm or more can be selected and used. Specific photopolymerization initiators include α-diketones such as camphorquinone and 1-phenyl-1,2-propanedione; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6- Acylphosphine oxides such as trimethylbenzoyl) -phenylphosphine oxide; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- (4-methylthiophenyl)- Α-aminoalkylphenones such as 2-morpholinopropan-1-one; or bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) Examples include titanocenes such as 1-yl) phenyl) titanium and other titanocene compounds. Among these, α-diketones and acylphosphine oxides are preferable from the viewpoint of good polymerization activity and low harm to the living body, and camphorquinone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are more preferable. preferable.

On the other hand, a thermal polymerization initiator can be used in addition to the photopolymerization initiator to form a crosslinked structure.
Examples of thermal polymerization initiators include azo compounds, quinine, nitro compounds, acyl halides, hydrazones, mercapto compounds, pyrylium compounds, imidazoles, chlorotriazines, benzoins, benzoin alkyl ethers, diketones, phenones, and dilauroyl peroxide and NOF. Co. And organic peroxides such as 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane available as PERHEXA TMH.

  The polymerization initiator is often used at a concentration of about 0.01 to about 10% by weight, or about 0.01 to about 5% by weight, based on the total weight of the curable composition. A mixture of polymerization initiators may be used.

(Sheet forming method)
As a method for forming the curable composition into a sheet, a known method such as an extrusion casting method using a T die, an extrusion laminating method, a calendar method, an inflation method, or the like can be employed. Among these, from the viewpoint of handling properties, productivity, and the like, a melt molding method such as an extrusion casting method and an extrusion lamination method is preferable.

When selecting a melt molding that does not use a solvent, the curable composition for melt molding has a storage elastic modulus (G ′) at a shear rate of 1 Hz in an uncured state at 50,000 Pa or more at 20 ° C. It is preferable that it is 10,000 Pa or less at 160 degreeC.
If G ′ at 20 ° C. is in the above range, the shape can be maintained at room temperature after molding. If G ′ at 160 ° C. is in the above range, molding can be performed without entraining bubbles.

  The elastic modulus (storage elastic modulus) G ′ and the viscosity modulus (loss elastic modulus) G ″ and tan δ = G ″ / G ′ at various temperatures can be measured using a strain rheometer.

The molding temperature at the time of melt molding is appropriately adjusted depending on the flow characteristics, film forming properties, and the like, but is preferably 80 to 230 ° C, more preferably 90 to 160 ° C.
In the case of melt molding, the thickness of the sheet can be appropriately adjusted by the lip gap of the T die, the sheet take-up speed, and the like.

  And if necessary, the sheet | seat using this resin composition can be formed by extending | stretching the said sheet | seat uniaxially or biaxially, and also heat-processing.

(Formation of laminate)
Moreover, it can be set as the laminated body by which a release film is laminated | stacked on the at least single side | surface of the said sheet | seat from a viewpoint of blocking prevention and foreign material adhesion prevention. Or you may perform an embossing and various unevenness | corrugation (a cone, a pyramid shape, a hemispherical shape, etc.) processing as needed. Further, various surface treatments such as corona treatment, plasma treatment and primer treatment may be performed on the surface for the purpose of improving adhesion to various adherends.

The resin composition can be produced by irradiating a sheet of the curable composition produced as described above with heat and / or active energy rays.
Here, examples of active energy rays to be irradiated include ionizing radiation such as α rays, β rays, γ rays, neutron rays, and electron rays, ultraviolet rays, visible rays, etc., and particularly damages to optical device components. Ultraviolet rays are preferred from the viewpoint of suppression and reaction control. Moreover, it does not specifically limit regarding irradiation energy of an active energy ray, irradiation time, an irradiation method, etc., A polymerization initiator should just be activated and a (meth) acrylate component can be polymerized.

  In addition, when the viscosity of the curable composition is sufficiently low as a result of adding paraffin or isoparaffin as a softening agent, the resin composition can be formed by solventless coating on a film using a die coater or a comma coater. You may get

(coating)
Moreover, as another embodiment of the manufacturing method of this resin composition, the said curable composition can be dissolved in a suitable solvent and it can also implement using various coating methods. However, in this embodiment, it is necessary to consider in terms of manufacturing cost such as solvent recovery.
When the coating technique is used, the resin composition can be obtained by thermosetting in addition to the above active energy ray irradiation curing.

  In the case of selecting molding by a coating technique, examples of the cured composition include a cured composition having thermosetting properties in addition to a cured composition having active energy ray curability. When making a thermosetting composition, it is preferable to select and contain a polymerization initiator having a decomposition temperature higher than the drying temperature of the solvent.

  In the case of coating, the thickness of the sheet can be adjusted by the coating thickness and the solid content concentration of the coating liquid.

<Laminated body for image display device configuration, image display device>
By laminating an image display device constituent member on at least one surface of the resin composition, a laminate for constituting an image display device can be formed. An image display device using the laminate for constituting an image display device Can be configured.

The group comprising the touch panel, the image display panel, the surface protection panel, the retardation film, the polarizing film, the color filter, and the flexible substrate on at least one side of the sheet containing the resin composition or the sheet formed using the resin composition. It can be set as the laminated body for image display apparatuses provided with the structure by which any one or more of them are laminated | stacked.
An image display device can be constituted by using the laminate for constituting an image display device composed of any one kind or a combination of two or more kinds.

  Moreover, the sheet | seat formed using the sheet | seat containing this resin composition or this resin composition can be arrange | positioned as the said image display apparatus structural member on the display surface side and / or non-display surface side of an image display apparatus. . For example, in a top emission type flexible OLED display, a light emitting layer is formed on a resin substrate such as polyimide, and the light emitting layer side is a display surface. However, a sheet containing the resin composition or a sheet formed using the resin composition By disposing on the non-display surface side of the resin substrate, it is possible to prevent water from entering from the non-display surface side and moisture absorption of polyimide, which can contribute to extending the life of the OLED. Further, it is possible to suppress the deformation of the display surface and the influence of external force.

<Explanation of words>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X is preferably greater than X” or “preferably Y”. It also includes the meaning of “smaller”.
In addition, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), it is “preferably greater than X” or “preferably less than Y”. Includes intentions.

  The invention is further illustrated by the following examples. However, it is not intended that the present invention be limited by the following examples.

  The compounds and materials used in each example are shown below.

[Isobutylene polymer (A)]
(A) -1: Opanol N50SF (manufactured by BASF, polyisobutylene, Mw: 56,550,000 g / mol, (HSP δD: 15.1, δP: 0, δH: 0))
(A) -2: Tetrax 3T (manufactured by JXTG, polyisobutylene, Mw: 49,000 g / mol, (HSP δD: 15.1, δP: 0, δH: 0))
-(A) -3: IP solvent 2835 (Idemitsu Co., Ltd., isobutylene polymer)

[Monomer of Acrylate Polymer (B)]
(I) Monofunctional aliphatic (meth) acrylate (B) -1: S-1800 ACL (manufactured by Shin-Nakamura Chemical Co., Ltd., isostearyl acrylate, one acryloyloxy group added to a branched alkyl having 18 carbon atoms Acrylate (HSP distance from component (A): 3.74)
(B) -2: Blemmer CA (manufactured by NOF Corporation, hexadecyl acrylate, acrylate in which one acryloyloxy group is added to linear alkyl having 16 carbon atoms. HSP distance from component (A): 4.08 )

(Ii) Multifunctional (meth) acrylate (B) -3: A-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd., tricyclodecane dimethanol diacrylate, HSP distance from component (A): 7.77)
(B) -4: A-NOD-N (manufactured by Shin-Nakamura Chemical Co., Ltd., 1,9-nonanediol diacrylate, HSP distance from component (A): 7.00)
(B) -5: CD595 (Sartomer, 1,10-decanediol diacrylate, HSP distance from component (A): 6.65)

[Tackifier (C)]
-(C) -1: YS resin PX800 (manufactured by Yasuhara Chemical Co., Ltd., terpene resin)

(Polymerization initiator)
(D) -1: Darocur TPO (manufactured by BASF, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide)

<Manufacturing method>
Lab plast mill (manufactured by Toyo Seiki Seisakusho) with isobutylene polymer, monofunctional aliphatic (meth) acrylate, polyfunctional (meth) acrylate, tackifier, and polymerization initiator in the formulation shown in Table 1. Were kneaded at 110 ° C. and 60 rpm to obtain a curable composition which is a precursor of the resin composition of the present invention.
Subsequently, a molten curable composition is supplied between two sheets of polyethylene terephthalate film (Mitsubishi Chemical Corporation, Diafoil MRF38, thickness: 38 μm) that has been subjected to a release treatment, and between two heating rolls. By passing, a sandwich lamination was performed, and a release film was provided on both sides, and a sheet-like curable composition having a curable composition layer thickness of about 100 μm was obtained.
At this time, the temperature of the heating roll was 160 ° C., and the speed was 100 mm / min.

Next, the obtained sheet-like curable composition is irradiated with ultraviolet rays using a high-pressure mercury lamp so that the integrated light quantity at 365 nm is 2000 mJ / cm ² in a state where a release film is laminated, and 23 ° C. and 50% RH. The laminated body which provided the sheet | seat (sample) containing a resin composition in the intermediate | middle layer by curing for 15 hours or more.

<Evaluation test of curable composition and uncured sheet>
(HSP, HSP distance (Ra))
The HSP was obtained from the chemical structure by the Y-MB method installed in HSPiP (trade name) which is HSP integrated software.
HSP distance (Ra) is, when the the HSP of (meth) acrylate monomer _{(δD 1, δP 1, δH} 1) and then, isobutylene polymer to the HSP _{(A) (δD 2, δP} 2, δH 2) The following formula was used.
HSP distance (Ra) = {4 × ( δD 1 -δD 2) 2 + (δP 1 -δP 2) 2 + (δH 1 -δH 2) 2} 0.5

(Dynamic viscoelasticity)
The release film on both sides of the obtained laminate was peeled off, and a plurality of sheets (samples) were stacked to produce a sheet having a thickness of about 2 mm, and punched into a circle with a diameter of 20 mm. A rheometer (Eiko Seiki Co., Ltd.) Using a company-made MARS), measurement is performed under the conditions of adhesive jig: Φ20 mm parallel plate, strain: 0.1%, frequency: 1 Hz, temperature: −50 to 150 ° C., temperature increase rate: 3 ° C./min. Thus, the storage elastic modulus (G ′), loss elastic modulus (G ″), and loss tangent (tan δ) of the sheet (sample) were obtained.
In particular, the result of tan δ is shown in FIG.

(TEM observation)
The obtained sheet (sample) is dyed with ruthenium tetroxide and freeze-cut using a Leica microtome EM UC7 to produce a plurality of sections, and arbitrarily three sections are obtained from the obtained sections. Were extracted using a Hitachi transmission electron microscope “H-7650” at an acceleration voltage of 100 kv and a magnification of 1000 to 5000 times to confirm the dispersion state.
At this time, each of the three slices observed was randomly observed in 10 fields of view, and if no “lumps with a maximum diameter of 1 μm” were observed in any field of view, it was judged as “none”. When “a lump having a maximum diameter of 1 μm or more” was observed in the field of view, it was judged as “present”.
The electron micrographs of the sheet (sample) obtained in Example 1 are shown in FIGS. 2 and 3, the electron micrographs of the sheet (sample) obtained in Example 3 are shown in FIGS. Electron micrographs of the obtained sheet (sample) are shown in FIGS.

(Adhesion test)
One release film of the obtained sheet (sample) was peeled off, and a 50 μm polyethylene terephthalate film (manufactured by Mitsubishi Plastics, Diafoil T100, thickness 50 μm) was bonded as a backing film to prepare a laminate.
After the laminated product was cut into a length of 150 mm and a width of 10 mm, the remaining release film was peeled off, and the exposed adhesive surface was roll-bonded to soda lime glass. The bonded product was subjected to autoclave treatment (60 ° C., gauge pressure 0.2 MPa, 20 minutes) and finished and bonded to prepare a sample for measuring adhesive strength.

The adhesion force (N / cm) with glass when the peeling force measurement sample was peeled at a peeling angle of 180 ° and a peeling speed of 60 mm / min was measured and evaluated according to the following criteria.
○: Adhesive strength of 1 N / cm or more ×: Adhesive strength of less than 1 N / cm Table 1 shows the results for the respective resin compositions obtained.

(Retention force test)
Sheets (samples) having a thickness of 100 μm prepared in Examples and Comparative Examples were cut into 40 mm × 50 mm, a single-sided release film was peeled off, and a polyethylene terephthalate film for backing (Diafoil S-100, manufactured by Mitsubishi Plastics, Inc.). , A thickness of 38 μm) was back-attached with a hand roller, and then cut into a strip shape having a width of 25 mm and a length of 100 mm to obtain a test piece.
Next, the remaining release film was peeled off and attached to a SUS plate (120 mm × 50 mm × thickness 1.2 mm) with a hand roller so that the application area was 25 mm × 25 mm.

Then, after the test piece was cured for 15 minutes in an atmosphere of 40 ° C., a weight of 1 kgf was attached to the test piece in the vertical direction and left standing, and then the falling time (minutes) of the weight was measured. Evaluated by criteria.
○: No fall within 30 minutes ×: Fall within 30 minutes
The results for the obtained resin compositions are shown in Table 1.

(Haze)
Haze is a state in which glass is bonded to both sides of a sheet (sample), and a total light transmittance is applied to JIS K7136 according to JIS K7361-1, using a haze meter (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze was measured accordingly. The results for the obtained resin compositions are shown in Table 1.

(Dampproof)
After measuring the thickness of the obtained sheet (sample), the release PET on both sides was peeled off, and a PET nonwoven fabric was attached instead, and the water vapor transmission rate at 40 ° C. and 90% Rh was measured by the JIS K7129B method. Evaluated by criteria.
○: Water vapor permeability in terms of 100 μm is 20 g / m ² · 24 h or less ×: Water vapor permeability in terms of 100 μm is over 20 g / m ² · 24 h

In order to compare those with slightly different thicknesses, in the case of a cured sheet having a cured sheet thickness of A μm and a water vapor transmission rate of B (g / m ² · 24 h), the formula A × B / 100 is used. It applied and calculated | required the value of 100 micrometer conversion. The results for the obtained resin compositions are shown in Table 1.

  As shown in FIGS. 2 to 5, the resin composition obtained in Examples 1 and 3, that is, the sheet (sample), is highly compatible with the isobutylene polymer (A) and the acrylate polymer, A lump having a maximum diameter of 1 μm or more, in other words, a dispersed phase consisting of an acrylate polymer (B) having a maximum diameter of 1 μm or more was not observed. Also in the resin composition, that is, the sheet (sample) obtained in Example 2, a lump having a maximum diameter of 1 μm or more, that is, a dispersed phase was not observed.

As can be seen from the results shown in Table 1 and FIG. 1, the resin compositions, ie, sheets (samples) obtained in Examples 1 to 3, have good adhesion, good holding power, and high transparency. And, it was excellent in water vapor barrier property.
In the resin compositions, that is, the sheets (samples) obtained in Comparative Examples 1 and 2, the maximum point of loss tangent in shearing at a frequency of 1 Hz is not in the range of -20 to 20 ° C. Therefore, it was inferior to the adhesive strength when it was made into a sheet.
Further, the resin compositions, that is, the sheets (samples) obtained in Comparative Examples 1 and 2, as shown in FIGS. A dispersed phase was observed. Therefore, it was inferior in transparency.

In Examples 1 to 3, although the content of the isobutylene polymer (A) is larger than that of the acrylate polymer (B), a large tan δ peak derived from polyisobutylene is not observed. This is different from the system using PCHMA described in the above. This is a phenomenon seen when using an acrylate polymer (B) mainly composed of a monofunctional (meth) acrylate having a long alkyl chain having 10 or more carbon atoms. In the conventional polyisobutylene IPN, Is a phenomenon that cannot be seen.
It is inferred that the long-chain alkyl side chain of the component (B) exhibits viscoelastic behavior like a single material as a result of increasing the molecular entanglement with the isobutylene polymer (A).

Claims (9)

Loss tangent in shearing at a frequency of 1 Hz including an isobutylene polymer (A) and an acrylate polymer (B) mainly composed of a monofunctional (meth) acrylate having a long alkyl chain having 10 or more carbon atoms tan δ) is a resin composition having at least one maximum point in the range of −20 to 20 ° C.,
A resin composition characterized in that when the resin composition is observed with a transmission electron microscope (magnification: 1000 to 5000 times), a lump having a maximum diameter of 1 μm or more is not observed.   The resin composition of Claim 1 which contains the said acrylate polymer (B) in the ratio of 5 to 100 mass parts with respect to 100 mass parts of said isobutylene polymers (A).   The resin composition according to claim 1 or 2, further comprising a tackifier (C), and the content of the tackifier (C) is less than 10% by mass.   The resin composition according to any one of claims 1 to 3, wherein a maximum value of loss tangent (tan δ) in shearing at a frequency of 1 Hz in a range of -20 to 20 ° C is 0.5 or more.   The sheet | seat containing the resin composition in any one of Claims 1-4.   The sheet | seat formed from the resin composition in any one of Claims 1-4.   A laminate in which a release film is laminated on at least one surface of the sheet according to claim 5 or 6.   At least one of the group consisting of a touch panel, an image display panel, a surface protection panel, a retardation film, a polarizing film, a color filter, and a flexible substrate is laminated on at least one side of the sheet according to claim 5 or 6. The laminated body for image display apparatuses provided with the structure formed. An image display device in which the sheet according to claim 5 or 6 is provided on a display surface side and / or a non-display surface side.