Polymer composition and polymer sheet

Abstract

Provided is a polymer composition capable of forming a polymer composition layer (serving as a sealing material) that exhibits high water vapor intrusion barrier properties and does not exhibit a decrease in the force of adhesion to a back sheet in an acceleration test. The polymer composition contains: (A) a low-molecular-weight olefin polymer that has an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer that does not contain a double bond in the olefin portion. The content of the (A) low-molecular-weight olefin polymer that has an acid anhydride group and / or a carboxyl group is 12 mass% or greater relative to 100 mass% of non-volatile components of the polymer composition.

Description

Polymer composition and polymer sheet

[0001] The present invention relates to a polymer composition useful for encapsulating electronic devices and the like, and a polymer sheet having a laminated structure including a polymer composition layer formed from the polymer composition.

[0002] To protect electronic devices, such as organic light-emitting diodes (OLEDs), that are sensitive to moisture, from moisture, there is a demand for encapsulants using resin compositions containing moisture-absorbing materials. While encapsulants can be in liquid or sheet form, sheet-shaped encapsulants are preferred because they can be attached to electronic devices to seal them. For example, Patent Document 1 proposes an encapsulating sheet containing a polymer composition layer using calcium oxide as a moisture-absorbing material, claiming that it can suppress horizontal moisture penetration. On the other hand, to prevent vertical moisture penetration, it is preferable to use a backsheet with low water vapor permeability (e.g., glass, inorganic compound-deposited PET, metal PET laminate, etc.). To prevent both horizontal and vertical moisture penetration, it is preferable to laminate the encapsulating sheet and the backsheet. Patent Document 2 proposes a resin composition containing a polymer-containing resin, moisture-absorbing particles such as calcium oxide, and an organic solvent-soluble dispersant, and a resin film (for sealing electronic devices) formed from the resin composition, claiming that it suppresses moisture penetration.

[0003] JP 2022-21714 A Patent No. 7264067 A

[0004] However, when calcium oxide absorbs moisture and becomes calcium hydroxide, the polymer composition changes, which reduces the adhesive strength between the back sheet and the resin layer of the sealing sheet. Therefore, although it is possible to delay moisture penetration from the horizontal direction, the adhesive strength between the back sheet and the resin layer of the sealing sheet decreases due to moisture absorption at the sealing edge, causing the problem of back sheet peeling, resulting in poor appearance and preventing further improvement of moisture barrier properties.

[0005] The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a polymer composition that can form a polymer composition layer (as an encapsulant) that exhibits high water vapor barrier properties and does not show a decrease in adhesion to a backsheet in an accelerated test.

[0006] As a result of intensive investigations aimed at solving the above-mentioned problems, the present inventors have found that by blending the following components (A) to (C), a polymer composition can be obtained that is capable of forming a polymer composition layer (as an encapsulant) that exhibits high water vapor barrier properties and does not show a decrease in adhesion to a backsheet in an accelerated test, and have completed the present invention.

[0007] That is, the present invention has the following features. [1] A polymer composition containing the following components: (A) a low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer containing no double bonds in the olefin moiety, wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 12% by mass or more relative to 100% by mass of the non-volatile content of the polymer composition. [2] The polymer composition according to [1], further containing (D) a low-molecular-weight olefin polymer other than (A). [3] The polymer composition according to [1] or [2], further containing (E) a high-molecular-weight olefin polymer other than (C). [4] The polymer composition according to any one of [1] to [3], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group has a number-average molecular weight of 950 to 20,000. [5] The polymer composition according to any one of [1] to [4], wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 16 to 24% by mass, based on 100% by mass of the non-volatile content of the polymer composition. [6] The polymer composition according to any one of [1] to [5], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is an acid anhydride-modified low-molecular-weight olefin polymer. [7] The polymer composition according to [6], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is a maleic anhydride-modified low-molecular-weight olefin polymer. [8] The polymer composition according to any one of [1] to [7], wherein (B) the water-absorbing filler is calcium oxide. [9] The polymer composition according to any one of [1] to [8], wherein (B) the median diameter of the water-absorbing filler is 0.3 to 5 μm.

[10] The BET specific surface area of ​​(B) the water-absorbing filler is 1 to 30 m ２ / g.

[11] The polymer composition according to any one of [1] to

[10] , wherein the number average molecular weight of (C) the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety exceeds 20,000 and is 5,000,000 or less.

[12] The polymer composition according to any one of [1] to

[11] , wherein the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety contains no isoprene units.

[13] The polymer composition according to any one of [1] to

[12] , wherein the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety is a high molecular weight styrene-ethylene-ethylene-propylene-styrene copolymer containing no double bond in the olefin moiety.

[14] The polymer composition according to any one of [1] to

[13] , wherein the amount of styrene units in the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety is 30% by weight or less based on the total of styrene units and olefin units.

[15] A polymer sheet having a laminate structure comprising a polymer composition layer formed from the polymer composition according to any one of [1] to

[14] .

[16] The polymer sheet according to

[15] , which is used for sealing an electronic device.

[17] An electronic device sealed with the polymer sheet according to

[15] or

[16] .

[0008] The present invention also has the following features. [1] A polymer composition containing the following components: (A) a low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer containing no double bonds in the olefin moiety. [2] The polymer composition according to [1], further containing (D) a low-molecular-weight olefin polymer other than (A). [3] The polymer composition according to [1] or [2], further containing (E) a high-molecular-weight olefin polymer other than (C). [4] The polymer composition according to any one of [1] to [3], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group has a number-average molecular weight of 950 to 20,000. [5] The polymer composition according to any one of [1] to [4], wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 2 to 20% by mass, based on 100% by mass of the non-volatile content of the polymer composition. [6] The polymer composition according to any one of [1] to [5], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is an acid anhydride-modified low-molecular-weight olefin polymer. [7] The polymer composition according to [6], wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is a maleic anhydride-modified low-molecular-weight olefin polymer. [8] The polymer composition according to any one of [1] to [7], wherein (B) the water-absorbing filler is calcium oxide. [9] The polymer composition according to any one of [1] to [8], wherein (B) the median diameter of the water-absorbing filler is 0.3 to 5 μm.

[10] The polymer composition according to any one of [1] to [8], wherein (B) the BET specific surface area of ​​the water-absorbing filler is 1 to 30 m ２ / g.

[11] The polymer composition according to any one of [1] to

[10] , wherein the number average molecular weight of (C) the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety exceeds 20,000 and is 5,000,000 or less.

[12] The polymer composition according to any one of [1] to

[11] , wherein the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety contains no isoprene units.

[13] The polymer composition according to any one of [1] to

[12] , wherein the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety is a high molecular weight styrene-ethylene-ethylene-propylene-styrene copolymer containing no double bond in the olefin moiety.

[14] The polymer composition according to any one of [1] to

[13] , wherein the amount of styrene units in the high molecular weight styrene-olefin polymer containing no double bond in the olefin moiety is 30% by weight or less based on the total of styrene units and olefin units.

[15] A polymer sheet having a laminate structure comprising a polymer composition layer formed from the polymer composition according to any one of [1] to

[14] .

[16] The polymer sheet according to

[15] , which is used for sealing an electronic device.

[17] An electronic device sealed with the polymer sheet according to

[15] or

[16] .

[0009] According to the present invention, it is possible to provide a polymer composition capable of forming a polymer composition layer (as an encapsulant) that exhibits high water vapor barrier properties and does not show a decrease in adhesion to a backsheet in an accelerated test, and a polymer sheet having a laminate structure including a polymer composition layer formed from the polymer composition.

[0010] The present invention will be described below with reference to preferred embodiments. [Polymer composition] The polymer composition of the present invention contains the following components (A) to (C) as essential components: (A) a low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer containing no double bonds in the olefin moiety, wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 12% by mass or more relative to 100% by mass of the non-volatile content of the polymer composition.

[0011] The polymer composition of the present invention also contains, as essential components, the following components (A) to (C): (A) a low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer containing no double bonds in the olefin moiety.

[0012] In this specification, "olefin polymer" means a polymer in which structural units derived from olefins (hereinafter sometimes abbreviated as "olefin units") are the main structural units (i.e., the amount of olefin units is the largest among all structural units). Note that, hereinafter, "structural units derived from butene," which are olefin units, may be abbreviated as "butene units," etc.

[0013] The olefin polymer may be an olefin resin (e.g., a propylene-butene copolymer) or an olefin rubber (e.g., a butyl rubber, i.e., an isobutylene-isoprene copolymer). In this specification, "olefin resin" means an olefin polymer that cannot form a rubbery elastomer by crosslinking, and "olefin rubber" means an olefin polymer that can form a rubbery elastomer by crosslinking.

[0014] The olefin is preferably a monoolefin having one olefinic carbon-carbon double bond and / or a diolefin having two olefinic carbon-carbon double bonds. Examples of monoolefins include α-olefins such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. Examples of diolefins include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene.

[0015] The olefin-based polymer may be a homopolymer or a copolymer. The copolymer may be a random copolymer or a block copolymer. The olefin-based polymer may also be a copolymer of an olefin and a monomer other than an olefin. Examples of the olefin-based copolymer include an ethylene-non-conjugated diene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-non-conjugated diene copolymer, an ethylene-butene copolymer, an ethylene-propylene-butene copolymer, a propylene-butene copolymer, a propylene-butene copolymer, a propylene-butene-non-conjugated diene copolymer, an isobutylene-isoprene copolymer, a styrene-isobutylene copolymer, a styrene-isobutylene-styrene copolymer, a styrene-butylene-butadiene copolymer, and a styrene-ethylene-butylene copolymer.

[0016] In this specification, "low molecular weight" means a number average molecular weight of 20,000 or less, preferably 10,000 or less, and more preferably 6,000 or less. "High molecular weight" means a number average molecular weight of more than 20,000, preferably 50,000 or more, and more preferably 100,000 or more. The number average molecular weight in the present invention is measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0017] (GPC measurement conditions) Measuring apparatus: "HLC-8420GPC" manufactured by Tosoh Corporation Column: Guard column "HXL-L" manufactured by Tosoh Corporation + "TSK-GEL SuperHZ2000" manufactured by Tosoh Corporation + "TSK-GEL SuperHZ2000" manufactured by Tosoh Corporation + "TSK-GEL SuperHZ3000" manufactured by Tosoh Corporation + "TSK-GEL SuperHZ4000" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: "GPC workstation EcoSEC-WorkStation" manufactured by Tosoh Corporation Column temperature: 40°C Developing solvent: tetrahydrofuran Flow rate: 0.35 mL / min Standard: In accordance with the measurement manual for the "GPC workstation EcoSEC-WorkStation", the following monodisperse polystyrene with a known molecular weight is used. TSKgel F-80, F-10, A-5000, A-500 (manufactured by Tosoh Corporation) Sample: 0.2% by mass (in terms of resin solid content) tetrahydrofuran solution filtered through a microfilter (10 μL)

[0018] Each component will be described in detail below. Unless otherwise specified in this specification, each component may be used alone or in combination of two or more types.

[0019] <Component (A)> The component (A) is a low-molecular-weight olefin polymer having an acid anhydride group (i.e., a carbonyloxycarbonyl group (—CO—O—CO—)) and / or a carboxyl group. Examples of the acid anhydride group include a group derived from succinic anhydride, a group derived from maleic anhydride, and a group derived from glutaric anhydride. The component may have one or more types of acid anhydride groups. By incorporating the component (A), it is possible to obtain a polymer composition layer that is resistant to deformation and can maintain its shape. Without incorporating the component (A), film formation is difficult. Furthermore, the component (A) forms a crosslinked structure through a crosslinking reaction between the acid anhydride group and the carboxyl group, or through coordination of the acid anhydride group and the carboxyl group to a water-absorbing filler (such as calcium oxide), thereby enabling the water-absorbing filler (component (B)) to be dispersed well in the polymer composition and also enabling the component to exhibit water vapor barrier properties.

[0020] When a low-molecular-weight olefin polymer having an acid anhydride group is used as component (A), the concentration of the acid anhydride group in the polymer is preferably 0.05 to 10 mmol / g, more preferably 0.10 to 5 mmol / g. The concentration of the acid anhydride group is obtained from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of the polymer, in accordance with JIS K 2501.

[0021] When a low-molecular-weight olefin polymer having carboxyl groups is used as component (A), the concentration of carboxyl groups in the polymer is preferably 0.05 to 20 mmol / g, more preferably 0.10 to 10 mmol / g. The concentration of carboxyl groups is obtained from the acid value, which is defined as the number of milligrams of potassium hydroxide required to neutralize the acid present in 1 g of polymer, in accordance with JIS K 2501.

[0022] When a low-molecular-weight olefin polymer having an acid anhydride group and a carboxyl group is used as the component (A), the total concentration of the acid anhydride group and the carboxyl group in the polymer is preferably 0.05 to 20 mmol / g, and more preferably 0.10 to 10 mmol / g.

[0023] The component (A) can be produced, for example, by (i) graft-modifying an olefin polymer with an unsaturated compound having an acid anhydride group and / or a carboxyl group (e.g., maleic anhydride) under radical reaction conditions, or by (ii) copolymerizing an unsaturated compound having an acid anhydride group and / or a carboxyl group with an α-olefin.

[0024] In one embodiment of the present invention, the component (A) is a low molecular weight copolymer, (i) preferably at least one selected from the group consisting of polybutene having an acid anhydride group and / or a carboxyl group, isobutylene-isoprene copolymer having an acid anhydride group and / or a carboxyl group (i.e., butyl rubber), ethylene-propylene copolymer having an acid anhydride group and / or a carboxyl group, propylene-butene copolymer having an acid anhydride group and / or a carboxyl group, ethylene-methyl methacrylate copolymer having an acid anhydride group and / or a carboxyl group, styrene-butylene-butadiene copolymer having an acid anhydride group and / or a carboxyl group, styrene-ethylene-butylene copolymer having an acid anhydride group and / or a carboxyl group, and ethylene-propylene-butene copolymer having an acid anhydride group and / or a carboxyl group, (ii) More preferably, it is at least one selected from the group consisting of polybutene having an acid anhydride group and / or a carboxyl group, isobutylene-isoprene copolymer having an acid anhydride group and / or a carboxyl group, ethylene-propylene copolymer having an acid anhydride group and / or a carboxyl group, styrene-ethylene-butylene copolymer having an acid anhydride group and / or a carboxyl group, and propylene-butene copolymer having an acid anhydride group and / or a carboxyl group; (iii) Even more preferably, it is at least one selected from the group consisting of polybutene having an acid anhydride group, isobutylene-isoprene copolymer having an acid anhydride group, ethylene-propylene copolymer having an acid anhydride group, propylene-butene copolymer having an acid anhydride group, and styrene-ethylene-butylene copolymer having an acid anhydride group; (iv) Particularly preferably, it is at least one selected from the group consisting of polybutene having an acid anhydride group, isobutylene-isoprene copolymer having an acid anhydride group, and ethylene-propylene copolymer having an acid anhydride group.

[0025] In another embodiment of the present invention, the component (A) is preferably an acid anhydride-modified low-molecular-weight olefin polymer, more preferably a maleic anhydride-modified low-molecular-weight olefin polymer. Note that the terms "acid anhydride-modified low-molecular-weight olefin polymer" and "maleic anhydride-modified low-molecular-weight olefin polymer" are synonymous with "low-molecular-weight olefin polymer having an acid anhydride group" and "low-molecular-weight olefin polymer having a maleic anhydride group."

[0026] The number average molecular weight of the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is not particularly limited as long as it is 20,000 or less, but from the viewpoints of preventing cissing during application of a varnish of the polymer composition, imparting moisture resistance to the formed polymer composition layer, and improving mechanical strength, the number average molecular weight is preferably 950 or more, more preferably 1,200 or more. On the other hand, from the viewpoints of achieving good application properties of a varnish of the polymer composition and good compatibility with other components in the polymer composition, the number average molecular weight is preferably 10,000 or less, more preferably 6,000 or less.

[0027] Next, specific examples of low-molecular-weight olefin polymers having acid anhydride groups and / or carboxyl groups will be described. Specific examples of polyisobutylene resins or polybutene resins include "HV-300M" (acid value: 65 mg KOH / g, acid anhydride group concentration: 1.16 mmol / g, number average molecular weight: 2,100) manufactured by Toho Chemical Industry Co., Ltd., "HV-100M" (acid value: 82 mg KOH / g, acid anhydride group concentration: 1.46 mmol / g, number average molecular weight: 1,218) manufactured by Toho Chemical Industry Co., Ltd., and "DOVERMULSE H1000" (acid value: 54 mg KOH, acid anhydride group concentration: 0.96 mmol / g, number average molecular weight: 1,204) manufactured by DOVER. A specific example of the ethylene-propylene copolymer is "Lucant A-5260" manufactured by Mitsui Chemicals, Inc. (acid anhydride group concentration: 0.44 mmol / g, number average molecular weight: 5,400).

[0028] The content of component (A) in the polymer composition of the present invention is not particularly limited. However, from the viewpoint of imparting good coatability and moldability and ensuring handleability (suppression of tackiness), the content is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less, relative to 100% by mass of the nonvolatile content of the polymer composition. On the other hand, from the viewpoint of ensuring good wet heat resistance and dispersibility of the water-absorbing filler (component (B)), the content is preferably 2% by mass or more, more preferably 9% by mass or more, and particularly preferably 16% by mass or more, relative to 100% by mass of the nonvolatile content of the polymer composition. In one embodiment of the present invention, the content of component (A) is preferably 2 to 40% by mass, more preferably 9 to 30% by mass, and even more preferably 16 to 20% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition. In another embodiment of the present invention, the content of component (A) is preferably 2 to 20% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition. In yet another embodiment of the present invention, the content of the component (A) is 12% by mass or more, preferably 13% by mass or more, more preferably 14% by mass or more, even more preferably 15% by mass or more, still more preferably 16% by mass or more, and particularly preferably 16 to 24% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0029] <Component (B)> The component (B) is a water-absorbing filler. By adding the component (B), it is possible to impart water vapor barrier properties to the formed polymer composition layer.

[0030] The water-absorbing filler is not particularly limited as long as it is a filler capable of absorbing moisture, and examples thereof include metal oxides such as calcium oxide, magnesium oxide, strontium oxide, aluminum oxide, barium oxide, calcined hydrotalcite, and calcined dolomite, metal hydroxides such as calcium hydroxide, magnesium hydroxide, strontium hydroxide, aluminum hydroxide, barium hydroxide, and semi-calcined hydrotalcite, and molecular sieves. Among these, calcium oxide and semi-calcined hydrotalcite are preferred from the viewpoint of water absorbency, and semi-calcined hydrotalcite is preferred from the viewpoint of transparency, and calcium oxide is preferred from the viewpoint of water vapor barrier properties. Only one type of water-absorbing filler may be used, or two or more types may be used in combination.

[0031] The median diameter (D50) of component (B) is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less to prevent the water-absorbing filler from damaging the electronic device during the encapsulation process. From the viewpoint of dispersibility of component (B) in the polymer composition, the median diameter (D50) is preferably 0.2 μm or more, more preferably 0.3 μm or more, and even more preferably 0.4 μm or more. In one embodiment of the present invention, the median diameter of component (B) is preferably 0.2 to 20 μm, more preferably 0.3 to 10 μm, and even more preferably 0.4 to 5 μm. The median diameter of component (B) can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the measurement can be performed by creating a particle size distribution of component (B) on a volume basis using a laser diffraction particle size distribution analyzer. A measurement sample prepared by dispersing component (B) in ethanol using ultrasonic waves can be preferably used. As the laser diffraction scattering particle size distribution measuring device, an LA-500 manufactured by Horiba Ltd. or the like can be used.

[0032] The BET specific surface area of ​​the component (B) is preferably 1 m² from the viewpoint of the water vapor barrier properties of the polymer composition layer to be formed. ２ / g or more, more preferably 1.5m ２ / g or more, and more preferably 2m ２On the other hand, from the viewpoint of dispersibility of the component (B) in the polymer composition, it is preferably 50 m ２ / g, more preferably 30m ２ / g or less, and more preferably 25m ２ In one embodiment of the present invention, the BET specific surface area of ​​component (B) is preferably 1 to 50 m ２ / g, more preferably 1.5 to 30m ２ / g, and more preferably 2 to 25m ２ The BET specific surface area of ​​component (B) can be calculated according to the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM Model 1210, manufactured by Mountech Co., Ltd.) and then using the BET multipoint method.

[0033] The content of the (B) component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on 100% by mass of the nonvolatile content of the polymer composition, from the viewpoint of the water vapor barrier property of the polymer composition layer, and is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, based on 100% by mass of the nonvolatile content of the polymer composition. In one embodiment of the present invention, the content of the (B) component is preferably 5 to 80% by mass, more preferably 10 to 75% by mass, and even more preferably 15 to 70% by mass, based on 100% by mass of the nonvolatile content of the polymer composition.

[0034] <Component (C)> Component (C) is a high-molecular-weight styrene-olefin polymer that does not contain a double bond in the olefin moiety. By incorporating component (C), it is possible to improve the film-forming properties of the polymer composition and improve the adhesion of the formed polymer composition layer to the backsheet (suppressing peeling of the backsheet).

[0035] In this specification, the "styrene-olefin polymer" of the "high molecular weight styrene-olefin polymer containing no double bonds in the olefin moiety" refers to a copolymer of styrene and an olefin, and may be a random copolymer or a block copolymer. Examples of the olefin include monoolefins having one olefinic carbon-carbon double bond and diolefins having two olefinic carbon-carbon double bonds. Examples of the monoolefin include α-olefins such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. Examples of the diolefin include 1,3-butadiene, 1,3-pentadiene, and 2,3-dimethylbutadiene. When a diolefin is used, the olefin moiety of the styrene-olefin polymer contains a double bond. However, since the component (C) in the present invention is a high molecular weight styrene-olefin polymer "containing no double bonds in the olefin moiety," the olefin moiety is hydrogenated.

[0036] In the (C) component, from the viewpoint of improving the adhesion of the formed polymer composition layer to the back sheet (suppressing peeling of the back sheet), it is preferable that the benzene ring of the styrene unit is not hydrogenated. Furthermore, from the viewpoint of preventing deterioration over time due to double bonds remaining in the polymer, it is preferable that the (C) component does not contain an isoprene unit. Furthermore, from the viewpoint of the water vapor barrier property of the polymer composition, the amount of styrene units in the (C) component is preferably 30 wt% or less, more preferably 18 wt% or less, and even more preferably 12 wt% or less, based on the total of styrene units and olefin units. From the viewpoint of improving the mechanical strength of the polymer composition, it is preferably 1 wt% or more, more preferably 2 wt% or more, and even more preferably 5 wt%.

[0037] Examples of high molecular weight styrene-olefin polymers that do not contain a double bond in the olefin moiety include styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-isobutylene-styrene copolymer (SIBS), styrene-ethylene-propylene-styrene copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), with SEEPS being preferred. Specific examples include "TUFTEC M1911" (maleic acid-modified SEBS) manufactured by Asahi Kasei Corporation, "TUFTEC H1043" (SEBS) manufactured by Asahi Kasei Corporation, "SIBSTAR 103T-UL" (SIBS) manufactured by Kaneka Corporation, "SEPTON 2004F" (SEPS) manufactured by Kuraray Co., Ltd., "HYBRAR7311F" (SEEPS) manufactured by Kuraray Co., Ltd., "TUFTEC H1062" (SEBS) manufactured by Asahi Kasei Corporation, and "SEPTON 4033" (SEEPS) manufactured by Kuraray Co., Ltd.

[0038] The number average molecular weight of the high molecular weight styrene-olefin polymer that does not contain a double bond in the olefin moiety is not particularly limited as long as it exceeds 20,000. From the viewpoints of the adhesive strength of the formed polymer composition layer to the backsheet and the mechanical strength, however, this number average molecular weight is preferably 50,000 or more, and particularly preferably 100,000 or more, and from the viewpoint of ensuring good compatibility with the (A) component, it is preferably 5,000,000 or less, and particularly preferably 2,000,000 or less.

[0039] The content of component (C) in the polymer composition of the present invention is not particularly limited. However, from the viewpoint of the water vapor barrier property and mechanical strength of the formed polymer composition layer, the content is preferably 1% by mass or more, more preferably 1.5% by mass or more, and particularly preferably 2% by mass or more, relative to 100% by mass of the nonvolatile content of the polymer composition. On the other hand, from the viewpoint of good adhesion and flexibility of the formed polymer composition layer to the backsheet, and from the viewpoint of ensuring handleability (suppression of tack), the content is preferably 50% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less, relative to 100% by mass of the nonvolatile content of the polymer composition. In one embodiment of the present invention, the content of component (C) is preferably 1 to 50% by mass, more preferably 2 to 20% by mass, and even more preferably 2 to 10% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0040] The total content of the components (A) and (C) in the polymer composition of the present invention is not particularly limited, but from the viewpoint of ensuring good wet heat resistance and adhesion, the total content is preferably 5 to 45 mass%, more preferably 10 to 40 mass%, and even more preferably 15 to 35 mass%, relative to 100 mass% of the nonvolatile content of the polymer composition.

[0041] <Component (D)> The polymer composition of the present invention may further contain a low-molecular-weight olefin polymer other than (A), i.e., a low-molecular-weight olefin polymer having neither an acid anhydride group nor a carboxyl group (component (D)), as long as the effects of the present invention are exhibited.

[0042] The number average molecular weight of component (D) is not particularly limited as long as it is 20,000 or less, but from the viewpoint of good coatability of the varnish of the polymer composition, it is preferably 10,000 or less, and more preferably 6,000 or less.

[0043] Commercially available products can be used for component (D). Examples of such commercially available products include ENEOS "HV-100" (liquid polybutene), ENEOS "HV-300" (liquid polybutene), ENEOS "HV-1900" (liquid polybutene), ENEOS "HV-50" (liquid polybutene), ENEOS "HV-35" (liquid polybutene), Kothari "950MW" (liquid polybutene), Kothari "2400MW" (liquid olefin polymer), INEOS "H-1900" (liquid polybutene), and INEOS " H-6000 (liquid polybutene), INEOS "H-18000" (liquid polybutene), NOF Corporation "200N" (liquid polybutene), Nippon Soda "BI-2000" (liquid hydrogenated polybutadiene), Nippon Soda "BI-3000" (liquid hydrogenated polybutadiene), Nippon Soda "GI-3000" (liquid hydrogenated polybutadiene), Mitsui Chemicals "Lucant LX100" (liquid olefin polymer), Mitsui Chemicals "Lucant LX400" (liquid olefin polymer), Idemitsu Showa Shell "Poly bd R-45HT" (liquid butadiene rubber), Idemitsu Showa Shell "Poly bd R-15HT" (liquid butadiene rubber), Idemitsu Showa Shell "Poly ip" (liquid polyisoprene), Nippon Soda's "B-1000" (liquid polybutadiene), Nippon Soda's "B-3000" (liquid polybutadiene), Nippon Soda's "G-3000" (liquid polybutadiene), Kuraray's "LIR-30" (liquid polyisoprene), Kuraray's "LIR-390" (liquid polyisoprene), Kuraray's "LIR-290" (liquid polyisoprene), Kuraray's "LBR-302" (liquid polybutadiene), Kuraray's "LBR-305" (liquid polybutadiene), Kuraray's "LBR-361" (liquid polybutadiene), Kuraray's "L-SBR-820" (liquid styrene-butadiene random copolymer), CRAY VALLEY's "Ricon" 154" (liquid butadiene), and CRAY VALLEY's "Ricon 184" (liquid styrene-butadiene random copolymer).

[0044] Component (D) is preferably liquid polybutene and / or liquid hydrogenated polybutadiene, more preferably liquid polybutene. In this specification, the terms "hydrogenation" and "hydrogenation" are used interchangeably.

[0045] The content of component (D) in the polymer composition of the present invention is not particularly limited. However, from the viewpoint of good adhesion and flexibility of the formed polymer composition layer to the backsheet, the content is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more, relative to 100% by mass of the nonvolatile content of the polymer composition. On the other hand, from the viewpoint of good adhesion and flexibility of the formed polymer composition layer to the backsheet and the ability to ensure handleability (suppression of tack), the content is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less, relative to 100% by mass of the nonvolatile content of the polymer composition. In one embodiment of the present invention, the content of component (D) is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and even more preferably 3 to 30% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0046] The total content of the components (A), (C), and (D) in the polymer composition of the present invention is not particularly limited, but from the viewpoint of ensuring good wet heat resistance, adhesiveness, and handleability (suppression of tack), the total content is preferably 5 to 60% by mass, more preferably 10 to 55% by mass, and even more preferably 15 to 50% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0047] The total content of the components (A) and (D) in the polymer composition of the present invention is not particularly limited, but from the viewpoint of ensuring good wet heat resistance and handleability (suppression of tack), the total content is preferably 5 to 55 mass%, more preferably 10 to 50 mass%, and even more preferably 15 to 45 mass%, relative to 100 mass% of the nonvolatile content of the polymer composition.

[0048] The total content of the components (C) and (D) in the polymer composition of the present invention is not particularly limited, but from the viewpoint of ensuring good wet heat resistance and adhesion, the total content is preferably 0.4 to 40 mass%, more preferably 0.6 to 35 mass%, and even more preferably 0.8 to 30 mass%, relative to 100 mass% of the nonvolatile content of the polymer composition.

[0049] <Component (E)> The polymer composition of the present invention may further contain (C) a high-molecular-weight olefin polymer (component (E)) other than the high-molecular-weight styrene-olefin polymer containing no double bond in the olefin moiety, as long as the effects of the present invention are exhibited.

[0050] The number average molecular weight of component (E) is not particularly limited as long as it exceeds 20,000. From the viewpoint of good coatability of the varnish of the polymer composition, etc., it is preferably 50,000 or more, and more preferably 100,000. From the viewpoint of ensuring good compatibility with component (A), it is preferably 5,000,000 or less, and particularly preferably 2,000,000 or less.

[0051] The component (E) is not particularly limited as long as it is a high-molecular-weight olefin polymer other than the component (C), and examples thereof include epoxy-modified high-molecular-weight olefin polymers and high-molecular-weight olefin polymers having acid anhydride groups and / or carboxyl groups.

[0052] The term "epoxy-modified high-molecular-weight olefin polymer" is synonymous with "high-molecular-weight olefin polymer having an epoxy group." The epoxy groups of the epoxy-modified high-molecular-weight olefin polymer form a crosslinked structure by reaction with acid anhydride groups / carboxyl groups in a low-molecular-weight olefin polymer (component (A)) having an acid anhydride group and / or a carboxyl group, thereby improving the dispersibility of a water-absorbing filler (component (B)) in the polymer composition and the water vapor barrier properties of the resulting polymer composition layer.

[0053] The epoxy group concentration in the epoxy-modified high-molecular-weight olefin polymer is preferably 0.05 to 10 mmol / g, more preferably 0.10 to 5 mmol / g, and is determined from the epoxy equivalent weight according to JIS K 7236-1995.

[0054] The epoxy-modified high-molecular-weight olefin polymer can be obtained, for example, by (i) graft-modifying an olefin polymer with an unsaturated compound having an epoxy group (e.g., glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, allyl glycidyl ether) under radical reaction conditions, or by (ii) copolymerizing an unsaturated compound having an epoxy group with an α-olefin.

[0055] Commercially available epoxy-modified high-molecular-weight olefin polymers can be used. Examples of such commercially available products include "ER829" (glycidyl methacrylate-modified propylene-butene random copolymer, epoxy group concentration: 0.64 mmol / g, number average molecular weight: 400,000) manufactured by Seiko PMC Corporation, "T-YP276" (glycidyl methacrylate-modified propylene-butene random copolymer, epoxy group concentration: 0.64 mmol / g, number average molecular weight: 57,000) manufactured by Seiko PMC Corporation, and "ER850" (glycidyl methacrylate-modified isobutylene-isoprene random copolymer, epoxy group concentration: 0.64 mmol / g, number average molecular weight: 57,000) manufactured by Seiko PMC Corporation. random copolymer, epoxy group concentration: 0.654 mmol / g, number average molecular weight: 99,200), "ER899" manufactured by Seiko PMC Corporation (glycidyl methacrylate modified butyl rubber, isobutene unit / isoprene unit: 98.9% / 1.1%, epoxy group concentration: 1.63 mmol / g, number average molecular weight: 102,000 (non-volatile content: 28%)), and "BF-7M" manufactured by Sumitomo Chemical Co., Ltd. (ethylene-glycidyl methacrylate-methyl acrylate copolymer, melt flow rate: 7 g / 10 min).

[0056] The epoxy-modified high-molecular-weight olefin polymer has a high molecular weight: (i) preferably at least one selected from the group consisting of ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-vinyl acetate copolymer, ethylene-glycidyl methacrylate-methyl acrylate copolymer, propylene-butene copolymer having epoxy groups, isobutylene-isoprene copolymer having epoxy groups (i.e., butyl rubber), and ethylene-methyl methacrylate copolymer having epoxy groups; (ii) more preferably at least one selected from the group consisting of propylene-butene copolymer having epoxy groups, isobutylene-isoprene copolymer having epoxy groups, and ethylene-methyl methacrylate copolymer having epoxy groups; (iii) still more preferably propylene-butene copolymer having epoxy groups and / or isobutylene-isoprene copolymer having epoxy groups; and (iv) particularly preferably propylene-butene copolymer having epoxy groups, or isobutylene-isoprene copolymer having epoxy groups.

[0057] When a propylene-butene copolymer having an epoxy group is used as the epoxy-modified high-molecular-weight olefin polymer, the amount of butene units in the copolymer is preferably 1 to 50 mass %, more preferably 2 to 45 mass %, and even more preferably 3 to 40 mass %, based on the total of propylene units and butene units. The amount of butene units is based on the propylene units and butene units excluding modified portions (for example, portions derived from glycidyl (meth)acrylate for introducing epoxy groups).

[0058] When an isobutylene-isoprene copolymer having epoxy groups (i.e., butyl rubber) is used as the epoxy-modified high-molecular-weight olefin polymer, the amount of isoprene units in the copolymer is preferably 0.1 to 20 mass%, more preferably 0.3 to 15 mass%, and even more preferably 0.5 to 10 mass%, based on the total of isobutylene units and isoprene units, from the viewpoint of yellowing resistance of the polymer composition layer, etc. The amount of isoprene units is based on the isobutylene units and isoprene units excluding modified portions (e.g., portions derived from glycidyl (meth)acrylate for introducing epoxy groups).

[0059] The high molecular weight olefin polymer having an acid anhydride group and / or a carboxyl group is similar to the above component (A) except that it has a high molecular weight.

[0060] The high-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group can be a commercially available product, such as "ER6003" manufactured by Seiko PMC Corporation (maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber, isobutene unit / isoprene unit: 98.9% / 1.1%, butyl methacrylate unit concentration: 0.32 mmol / g, acid anhydride group concentration: 0.46 mmol / g, number average molecular weight: 32,000 (non-volatile content: 39%)).

[0061] The content of component (E) in the polymer composition of the present invention is not particularly limited. However, from the viewpoint of good adhesion and flexibility of the formed polymer composition layer to the backsheet, the content is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more, relative to 100% by mass of the nonvolatile content of the polymer composition. On the other hand, from the viewpoint of good adhesion and flexibility of the formed polymer composition layer to the backsheet and the ability to ensure handleability (suppression of tack), the content is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less, relative to 100% by mass of the nonvolatile content of the polymer composition. In one embodiment of the present invention, the content of component (E) is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and even more preferably 3 to 30% by mass, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0062] <Other Components> The polymer composition of the present invention may contain components other than the components (A) to (E) (hereinafter, these may be referred to as "other components"), as long as the effects of the present invention are not impaired. Examples of other components include tackifiers, antioxidants, curing accelerators, plasticizers, etc. These may be used alone or in combination of two or more.

[0063] (Tackifier) ​​A tackifier is also called a tackifier, and is a resin that is blended with a plastic polymer to impart tackiness. The tackifier is not particularly limited, and preferred examples include terpene resins, modified terpene resins (hydrogenated terpene resins, terpene-phenol copolymer resins, aromatic modified terpene resins, etc.), coumarone resins, indene resins, and petroleum resins (aliphatic petroleum resins, hydrogenated alicyclic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, alicyclic petroleum resins, dicyclopentadiene petroleum resins and their hydrogenated products, etc.).

[0064] Examples of commercially available products that can be used as tackifiers include the following: Terpene resins include YS Resin PX and YS Resin PXN (both manufactured by Yasuhara Chemical Co., Ltd.), aromatic modified terpene resins include YS Resin TO and TR series (both manufactured by Yasuhara Chemical Co., Ltd.), hydrogenated terpene resins include Clearon P, Clearon M, and Clearon K series (both manufactured by Yasuhara Chemical Co., Ltd.), terpene phenol copolymer resins include YS Polystar 2000, Polystar U, Polystar T, Polystar S, and Mighty Ace G (all manufactured by Yasuhara Chemical Co., Ltd.), and hydrogenated alicyclic petroleum resins include Examples of suitable petroleum resins include Escorez 5300 series and 5600 series (both manufactured by ExxonMobil Corporation), aromatic petroleum resins include ENDEX 155 (manufactured by Eastman Co.), aliphatic aromatic copolymer petroleum resins include Quintone D100 (manufactured by Zeon Corporation), alicyclic petroleum resins include Quintone 1325 and Quintone 1345 (both manufactured by Zeon Corporation), and saturated hydrocarbon resins include Arkon P100, Arkon P125, Arkon P140 and TFS13-030 (all manufactured by Arakawa Chemical Industries, Ltd.).

[0065] The softening point of the tackifier is preferably 50 to 200° C., more preferably 90 to 180° C., and even more preferably 100 to 150° C., from the viewpoint of softening the polymer composition sheet in the lamination step and having the desired heat resistance. The softening point is measured by the ring and ball method in accordance with JIS K2207.

[0066] The tackifier may be used alone or in combination of two or more. The content of the tackifier in the polymer composition is not particularly limited. However, from the viewpoint of maintaining good moisture permeation resistance of the polymer composition, when a tackifier is used, the content is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, and particularly preferably 40% by mass or less, relative to 100% by mass of the nonvolatile content of the polymer composition. On the other hand, from the viewpoint of having sufficient adhesiveness, when a tackifier is used, the content is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, relative to 100% by mass of the nonvolatile content of the polymer composition.

[0067] Among these, petroleum resins are preferred from the viewpoints of adhesiveness, moisture resistance, transparency, etc. of the polymer composition. Examples of petroleum resins include aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, and alicyclic petroleum resins. Among these, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, and alicyclic petroleum resins are more preferred from the viewpoints of adhesiveness, moisture resistance, compatibility, etc. of the polymer composition. Furthermore, alicyclic petroleum resins are particularly preferred from the viewpoint of improving transparency. As the alicyclic petroleum resin, aromatic petroleum resins that have been subjected to hydrogenation treatment can also be used. In this case, the hydrogenation rate of the alicyclic petroleum resin is preferably 30 to 99%, more preferably 40 to 97%, and even more preferably 50 to 90%. If the hydrogenation rate is too low, there is a tendency for problems such as reduced transparency due to coloration to occur, and if the hydrogenation rate is too high, there is a tendency for production costs to increase. The hydrogenation rate is determined by the ratio of hydrogen on the aromatic ring before and after hydrogenation. １ It can be determined from the ratio of H-NMR peak intensities. As alicyclic petroleum resins, cyclohexane ring-containing hydrogenated petroleum resins and dicyclopentadiene-based hydrogenated petroleum resins are particularly preferred. One or more types of petroleum resins may be used in combination. The number average molecular weight Mn of the petroleum resin is preferably 100 to 2,500, more preferably 200 to 2,000, and even more preferably 300 to 1,500.

[0068] (Antioxidant) In the present invention, there are no particular limitations on the antioxidant, and known antioxidants can be used. By incorporating an antioxidant, the light resistance of the formed polymer composition layer can be improved. For example, "Irganox 1010" (hindered phenol-based antioxidant) manufactured by BASF can be mentioned. When an antioxidant is used, the content thereof is preferably 0.01 to 5 mass %, more preferably 0.05 to 2.5 mass %, and even more preferably 0.10 to 2 mass %, relative to 100 mass % of the nonvolatile content of the polymer composition.

[0069] (Curing Accelerator) In the present invention, a curing accelerator may be used to open the acid anhydride group of component (A) to promote the chelate crosslinking reaction and to disperse the water-absorbing filler well in the polymer composition. Examples of the curing accelerator include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, and organic phosphine compounds.

[0070] Examples of the imidazole compound include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenylimidazole, 2-dodecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Specific examples of the imidazole compound include Curesol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, and 2MA-OK (all manufactured by Shikoku Chemicals Corporation).

[0071] The tertiary and quaternary amine compounds are not particularly limited, and examples thereof include quaternary ammonium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and triethylmethylammonium 2-ethylhexanoate; diazabicyclo compounds such as DBU (1,8-diazabicyclo[5.4.0]undecene-7), DBN (1,5-diazabicyclo[4.3.0]nonene-5), DBU-phenolate, DBU-octylate, DBU-p-toluenesulfonate, DBU-formate, and DBU-phenol novolac resin salt; tertiary amines or salts thereof such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP); and dimethylurea compounds such as aromatic dimethylurea and aliphatic dimethylurea.

[0072] Examples of dimethylurea compounds include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by San-Apro Co., Ltd.); and aliphatic dimethylureas such as U-CAT3503N (manufactured by San-Apro Co., Ltd.). Among these, aromatic dimethylureas are preferably used from the viewpoint of curability.

[0073] Examples of the organic phosphine compound include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Specific examples of the organic phosphine compound include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, TPP-S (all manufactured by Hokko Chemical Industry Co., Ltd.), etc.

[0074] When a curing accelerator is used, the content thereof is preferably 0.001 to 5 mass%, more preferably 0.001 to 2.5 mass%, and even more preferably 0.001 to 1 mass%, relative to 100 mass% of the nonvolatile content of the polymer composition, in order to promote the crosslinking reaction of the acid anhydride groups and / or carboxyl groups of the component (A).

[0075] (Plasticizer) The use of a plasticizer can improve the flexibility and moldability of the polymer composition. The plasticizer is not particularly limited, but materials that are liquid at room temperature are preferably used. Specific examples of plasticizers include mineral oils such as paraffinic process oil, naphthenic process oil, liquid paraffin, polyethylene wax, polypropylene wax, and petrolatum; vegetable oils such as castor oil, cottonseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, and olive oil; and liquid poly-α-olefins such as liquid polybutene, hydrogenated liquid polybutene, liquid polybutadiene, and hydrogenated liquid polybutadiene. Liquid poly-α-olefins are preferred as the plasticizer used in the present invention, with liquid polybutadiene being particularly preferred. Furthermore, from the standpoint of adhesiveness, liquid poly-α-olefins with low molecular weights are preferred, with weight-average molecular weights in the range of 500 to 5,000, and preferably 1,000 to 3,000, being more preferred. These plasticizers may be used alone or in combination of two or more. Here, "liquid" refers to the state of the plasticizer at room temperature (25° C.) When a plasticizer is used, the content thereof is preferably 50% by mass or less relative to 100% by mass of the nonvolatile content of the polymer composition, from the viewpoint of not adversely affecting the electronic device.

[0076] <Method for Producing Polymer Composition> The method for producing the polymer composition of the present invention is not particularly limited, and examples thereof include a method in which the blending components are mixed using a kneading roller, a rotary mixer, or the like, with the addition of a solvent or the like as necessary, and the resulting mixture is dried.

[0077] The mixture can be dried conveniently by heating. Heating may be carried out under normal pressure or under reduced pressure. The heating temperature and heating time may vary depending on the components used. Those skilled in the art can appropriately set the heating temperature and heating time depending on the components used.

[0078] <Polymer Sheet and Manufacturing Method Thereof> The present invention also provides a polymer sheet having a laminated structure including a polymer composition layer formed from the polymer composition of the present invention.

[0079] The polymer composition layer of the polymer sheet may be formed by a method known to those skilled in the art. For example, the polymer composition layer may be formed by preparing a varnish by dissolving the above-mentioned components in an organic solvent, and then applying and drying the varnish onto a support. The non-volatile content of the varnish is preferably 20 to 80% by mass, more preferably 30 to 70% by mass.

[0080] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, etc., acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc., cellosolves such as cellosolve, carbitols such as butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. Only one organic solvent may be used, or two or more organic solvents may be used in combination.

[0081] The varnish can be dried conveniently by heating. Heating may be performed under normal pressure or under reduced pressure. The heating temperature and heating time may vary depending on the components and organic solvent used. Those skilled in the art can appropriately set the heating temperature and heating time depending on the components and organic solvent used.

[0082] When a polymer sheet is prepared using a polymer composition containing a liquid olefin polymer having an acid anhydride group and an epoxy-modified high-molecular-weight olefin polymer, the acid anhydride group is reacted with the epoxy group to form a crosslinked structure, thereby increasing the moisture resistance of the polymer composition layer and providing a polymer sheet with higher sealing performance (such as blocking performance against moisture and oxygen in the air).

[0083] The thickness of the polymer composition layer in the polymer sheet is preferably 1 to 200 μm, more preferably 2 to 180 μm.

[0084] Examples of supports used for the polymer sheet include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; cycloolefin polymers; polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate; polycarbonate; and plastic films such as polyimide. The surface of the support that is bonded to the polymer composition layer may be subjected to a release treatment. Examples of release treatments include release treatments using a release agent such as a silicone resin-based release agent, an alkyd resin-based release agent, or a fluororesin-based release agent.

[0085] The thickness of the support is not particularly limited, but from the viewpoint of ease of handling of the polymer sheet, it is preferably 10 to 150 μm, more preferably 20 to 100 μm.

[0086] The support used for the polymer sheet is preferably a support having a barrier layer (e.g., a plastic film having a barrier layer). By using a support with low moisture permeability, moisture absorption by the polymer composition layer can be prevented during storage of the polymer sheet. Examples of the barrier layer include inorganic films such as silica vapor deposition films, silicon nitride films, and silicon oxide films. The barrier layer may be composed of multiple layers of multiple inorganic films (e.g., silica vapor deposition films). Furthermore, the barrier layer may be composed of an organic material and an inorganic material, or may be a composite multilayer of an organic layer and an inorganic film.

[0087] The support having a barrier layer is, for example, a support having a water vapor transmission rate (WVTR) of 0.0005 (g / m ２A high-barrier plastic film having a water vapor permeability (g / m / 24 hr) or less can be used. ２ / 24hr) refers to the time it takes for an area of ​​1m to be measured under the specified temperature and humidity conditions described below. ２ This refers to the amount (g) of water vapor that permeates a film of this type over 24 hours. Examples of high-barrier plastic films include those manufactured by laminating a single layer or multiple layers of inorganic films, such as silicon oxide (silica), aluminum oxide, magnesium oxide, silicon nitride, silicon nitride oxide, SiCN, or amorphous silicon, onto the surface of a plastic film using chemical vapor deposition (e.g., chemical vapor deposition using heat, plasma, ultraviolet light, vacuum heat, vacuum plasma, or vacuum ultraviolet light) or physical vapor deposition (e.g., vacuum deposition, sputtering, ion plating, laser deposition, or molecular beam epitaxy) (see, for example, JP 2016-185705 A, Japanese Patent No. 5719106 A, Japanese Patent No. 5712509 A, Japanese Patent No. 5292358 A, etc.). To prevent cracking of the inorganic film, it is preferable to alternately laminate the inorganic film and a transparent, flat layer (e.g., a transparent plastic layer).

[0088] Furthermore, the support having a barrier layer may be, for example, a support having a WVTR of 0.01 (g / m ２ / 24hr) or more 1 (g / m ２ / 24 hr) or less. Examples of medium-barrier plastic films include those produced by vapor-depositing an inorganic film containing an inorganic substance such as silicon oxide (silica), aluminum oxide, magnesium oxide, silicon nitride, silicon nitride oxide, SiCN, or amorphous silicon onto the surface of a substrate as a barrier layer, or by applying a coating liquid containing a metal oxide and an organic resin having barrier properties to the substrate and drying it (see, for example, JP 2013-108103 A and JP 4028353 A).

[0089] The water vapor transmission rate can be measured using a water vapor transmission rate measuring device, PERMATRAN series (manufactured by MOCON Corporation) (in accordance with ISO 15106-2 and JIS K7129B).２ The specimen is cut into pieces, set in a jig using silicone grease, and then adjusted to a temperature of 40° C. and a humidity of 90% RH using ultrapure water, and the water vapor permeability is measured until it reaches a steady state.

[0090] Commercially available products may be used as the support having a barrier layer. Examples of commercially available medium-barrier plastic films include "Kurarista CI" manufactured by Kuraray Co., Ltd., "Techbarrier HX," "Techbarrier LX," and "Techbarrier L" manufactured by Mitsubishi Plastics, Inc., "IB-PET-PXB" manufactured by Dai Nippon Printing Co., Ltd., and "GL, GX series" manufactured by Toppan Printing Co., Ltd., while examples of commercially available high-barrier plastic films include "X-BARRIER" manufactured by Mitsubishi Plastics, Inc.

[0091] It is preferable that the polymer composition layer provided on the support is protected with a protective film. The protective film can be laminated on the polymer composition layer using a known device. Examples of devices used for laminating the protective film include a roll laminator, a press, and a vacuum pressure laminator.

[0092] Examples of the protective film include the above-mentioned plastic films. It is preferable that the surface of the protective film that is to be bonded to the polymer composition layer is subjected to a release treatment. Examples of the release treatment include a release treatment using a release agent such as a silicone resin-based release agent, an alkyd resin-based release agent, or a fluororesin-based release agent.

[0093] The thickness of the protective film is not particularly limited, but from the viewpoint of ease of handling of the polymer sheet, it is preferably 10 to 150 μm, more preferably 20 to 100 μm.

[0094] It is preferable to use a protective film having a barrier layer to prevent the polymer composition layer from absorbing moisture after drying. Examples of protective films having a barrier layer include the above-mentioned plastic films having a barrier layer. From the viewpoint of cost, etc., it is preferable to use the above-mentioned medium-barrier plastic film as the plastic film having a barrier layer used for the protective film.

[0095] <Uses> The polymer composition and polymer sheet of the present invention can be suitably used for sealing electronic devices that are sensitive to moisture, such as organic EL devices, organic light-emitting diodes (OLEDs), solar cells, and organic thin film transistors (OTFTs).

[0096] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples and can be practiced with appropriate modifications within the scope of the above and below aims, all of which are included within the technical scope of the present invention. Note that "parts" and "%" in the amounts of components and copolymerized units mean "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0097] <Components> The components used in the examples and comparative examples are as follows: Component (A): low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group "Lucant A-5260" (manufactured by Mitsui Chemicals, Inc.): maleic anhydride-modified liquid polyolefin, number-average molecular weight: 5,400 "HV-300M" (manufactured by Toho Chemical Industry Co., Ltd.): maleic anhydride-modified liquid polybutene, acid value: 65 mg KOH / g, acid anhydride group concentration: 1.16 mmol / g, number-average molecular weight: 2,100

[0098] (B) Component: Water-absorbent filler Calcium oxide A (manufactured by Yoshizawa Lime Industry Co., Ltd.): D50: 1.6 μm, BET specific surface area: 20 m ２ / g Calcium oxide B (manufactured by Inoue Lime Industry Co., Ltd.): D50: 2.6 μm, BET specific surface area: 2 m ２ / g "DHT-4C" (Kyowa Chemical Industry Co., Ltd.): semi-calcined hydrotalcite, D50: 400 nm, BET specific surface area: 15 m ２ / g

[0099] Component (C): High molecular weight styrene-olefin polymer "HYBRAR7311F" (manufactured by Kuraray Co., Ltd.): styrene-ethylene-ethylene-propylene-styrene copolymer, styrene component: 12% by weight, number average molecular weight: 130,000 "SEPTON 2004F" (manufactured by Kuraray Co., Ltd.): styrene-ethylene-propylene-styrene copolymer, styrene component: 18% by weight, number average molecular weight: 85,000 "TUFTEC H1062" (manufactured by Asahi Kasei Corporation): styrene-ethylene-butylene-styrene copolymer, styrene component: 18% by weight, number average molecular weight: 65,000 "SEPTON 4033" (manufactured by Kuraray Co., Ltd.): styrene-ethylene-ethylene-propylene-styrene copolymer, styrene component: 30% by weight, number average molecular weight: 200,000

[0100] Component (D): low-molecular-weight olefin polymer other than (A) "HV-1900" (manufactured by ENEOS Corporation): liquid polybutene, number-average molecular weight: 2,900, viscosity at 25°C: 460 Pa·s "BI-3000" (manufactured by Nippon Soda Co., Ltd.): liquid hydrogenated polybutadiene, number-average molecular weight: 3,300, viscosity at 25°C: 50 Pa·s

[0101] Component (E): High molecular weight olefin polymer other than (C) "ER6003" (manufactured by Seiko PMC): maleic anhydride-butyl methacrylate random copolymer modified butyl rubber, isobutene unit / isoprene unit: 98.9% / 1.1%, butyl methacrylate unit concentration: 0.32 mmol / g, acid anhydride group concentration: 0.46 mmol / g, number average molecular weight: 32,000 (non-volatile content: 39%) "ER899" (manufactured by Seiko PMC): glycidyl methacrylate modified butyl rubber, isobutene unit / isoprene unit: 98.9% / 1.1%, epoxy group concentration: 1.63 mmol / g, number average molecular weight: 102,000 (non-volatile content: 28%)

[0102] (Other Components): <Tackifier> - "Arcon P-125" (manufactured by Arakawa Chemical Industries, Ltd., hydrogenated petroleum resin, softening point: 125°C) <Antioxidant> - "Irganox 1010" (manufactured by BASF): hindered phenol-based antioxidant <Cure Accelerator> - 2,4,6-tris(dimethylaminomethyl)phenol (manufactured by Kayaku Nouryon, hereinafter abbreviated as "TAP")

[0103] Example 1 A varnish having the blending ratio shown in the table below was prepared by the following procedure, and a polymer sheet was prepared using the obtained varnish. The amount (parts) of each component used in the table below indicates the amount of non-volatile content of each component in the varnish.

[0104] Specifically, a mixture was obtained by dispersing maleic anhydride-modified liquid polyolefin (Lucant A-5260, manufactured by Mitsui Chemicals, Inc.), styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.), and calcium oxide A (manufactured by Yoshizawa Lime Industry Co., Ltd.) in an Ipsol solution (non-volatile content 60%) of hydrogenated petroleum resin (tackifier: Alcon P-125, manufactured by Arakawa Chemical Industries, Ltd.) using a triple roll mill.

[0105] To the resulting mixture, a hindered phenol-based antioxidant (Irganox 1010, manufactured by BASF), a curing accelerator (TAP, manufactured by Kayaku Nouryon Co., Ltd.), and toluene were added, and the resulting mixture was uniformly dispersed in a high-speed rotating mixer to obtain a varnish of a polymer composition.

[0106] A low-moisture permeable polyethylene terephthalate "HX" (trade name: PET: 12 μm: manufactured by Mitsubishi Chemical Corporation) was laminated to the other surface of a polyethylene terephthalate (PET) film "SP3000" (trade name: PET: 50 μm: manufactured by Toyo Cross Co., Ltd.) treated with a silicone-based release agent on one side. A laminate film was produced and used as a support. In addition, a low-moisture permeable polyethylene terephthalate "HX" (trade name: PET: 12 μm: manufactured by Mitsubishi Chemical Corporation) was laminated to the other surface of a polyethylene terephthalate (PET) film "SP8002K2" (trade name: PET: 25 μm: manufactured by Toyo Cross Co., Ltd.) treated with a silicone-based release agent on one side. A laminate film was produced and used as a protective film. The obtained varnish was uniformly applied to the release-treated surface of the support using a die coater and heated at 150 ° C. for 10 minutes to form a polymer composition layer. Thereafter, a polymer composition layer was laminated on the release-treated surface of the protective film to obtain a polymer sheet having a polymer composition layer with a thickness of 50 μm.

[0107] Example 2 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the maleic anhydride-modified liquid polyolefin (Lucant A-5260, manufactured by Mitsui Chemicals, Inc.) of component (A) was changed to maleic anhydride-modified liquid polybutene (HV-300M, manufactured by Toho Chemical Industry Co., Ltd.).

[0108] Example 3 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR 7311F, manufactured by Kuraray Co., Ltd.) used as component (C) was changed to a styrene-ethylene-propylene-styrene copolymer (SEPTON 2004F, manufactured by Kuraray Co., Ltd.).

[0109] Example 4 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) used as component (C) was changed to a styrene-ethylene-butylene-styrene copolymer (TUFTEC H1062, manufactured by Asahi Kasei Corporation).

[0110] Example 5 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR 7311F, manufactured by Kuraray Co., Ltd.) used as component (C) was changed to a styrene-ethylene-ethylene-propylene-styrene copolymer (SEPTON 4033, manufactured by Kuraray Co., Ltd.).

[0111] Example 6 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) of component (C) was changed from 4 parts to 1 part.

[0112] Example 7 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) of component (C) was changed from 4 parts to 2 parts.

[0113] Example 8 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) of component (C) was changed from 4 parts to 11 parts.

[0114] Example 9 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) of component (C) was changed from 4 parts to 15 parts.

[0115] Example 10 A polymer sheet having a polymer composition layer with a thickness of 50 μm was obtained in the same manner as in Example 1, except that calcium oxide A (manufactured by Yoshizawa Lime Industry Co., Ltd.) in component (B) was changed to calcium oxide B (manufactured by Inoue Lime Industry Co., Ltd.).

[0116] Example 11 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that calcium oxide A (manufactured by Yoshizawa Lime Industry Co., Ltd.) as component (B) was changed to semi-calcined hydrotalcite (DHT-4C, manufactured by Kyowa Chemical Industry Co., Ltd.).

[0117] Example 12 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) as component (C) was changed from 4 parts to 2 parts, and that maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber (ER6003, manufactured by Seiko PMC Co., Ltd.) as component (E) was further blended.

[0118] Example 13 A polymer sheet having a 50 μm thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) for the component (C) was changed from 4 parts to 2 parts, that liquid polybutene (HV-1900, manufactured by ENEOS Corporation) for the component (D) and maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber (ER6003, manufactured by Seiko PMC Co., Ltd.) for the component (E) were further blended, and that hydrogenated petroleum resin (tackifier: Arkon P-125, manufactured by Arakawa Chemical Industries, Ltd.) was not blended.

[0119] Example 14 A polymer sheet having a 50 μm thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) for the component (C) was changed from 4 parts to 2 parts, hydrogenated polybutadiene (BI-3000, manufactured by Nippon Soda Co., Ltd.) for the component (D) and maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber (ER6003, manufactured by Seiko PMC Co., Ltd.) for the component (E) were further blended, and hydrogenated petroleum resin (tackifier: Alcon P-125, manufactured by Arakawa Chemical Industries, Ltd.) was not blended.

[0120] Example 15 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) as component (C) was changed from 4 parts to 2 parts, and that glycidyl methacrylate-modified butyl rubber (ER899, manufactured by Seiko PMC Co., Ltd.) as component (E) was further blended.

[0121] Comparative Example 1 An attempt was made to prepare a polymer sheet having a 50 μm-thick polymer composition layer in the same manner as in Example 1, except that the maleic anhydride-modified liquid polyolefin (Lucant A-5260, manufactured by Mitsui Chemicals, Inc.) of component (A) was not blended.

[0122] Comparative Example 2 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) as component (C) was changed from 4 parts to 2 parts, calcium oxide A (manufactured by Yoshizawa Lime Industry Co., Ltd.) as component (B) was not blended, and maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber (ER6003, manufactured by Seiko PMC Co., Ltd.) as component (E) was further blended.

[0123] Comparative Example 3 A polymer sheet having a 50 μm-thick polymer composition layer was obtained in the same manner as in Example 1, except that the styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.), component (C), was not blended.

[0124] Comparative Example 4 A polymer sheet having a 50 μm thick polymer composition layer was obtained in the same manner as in Example 1, except that the amount of maleic anhydride-modified liquid polyolefin (Lucant A-5260, manufactured by Mitsui Chemicals, Inc.) as component (A) was changed from 19 parts to 10 parts, the amount of styrene-ethylene-ethylene-propylene-styrene copolymer (HYBRAR7311F, manufactured by Kuraray Co., Ltd.) as component (C) was changed from 4 parts to 1 part, liquid polybutene (HV-1900, manufactured by ENEOS Corporation) as component (D) was further blended, and the amount of hydrogenated petroleum resin (tackifier: Alcon P-125, manufactured by Arakawa Chemical Industries, Ltd.) was changed from 24 parts to 30 parts.

[0125] <Method for evaluating film-forming properties> The state of the polymer sheets produced in the examples and comparative examples was evaluated according to the following criteria: ◯ (Good): Film formation was good and usable as a pressure-sensitive adhesive sheet. × (Poor): Poor dimensional stability due to shrinkage when heated at 150°C for 10 minutes, or film formation was not possible.

[0126] <Method for evaluating adhesive strength> The protective film was peeled off from the polymer sheet (length 50 mm, width 20 mm) produced in the examples and comparative examples, and the exposed polymer composition layer was laminated onto the aluminum foil side of a composite film "PET-Tuki AL1N30" (backsheet; aluminum foil thickness 30 μm, polyethylene terephthalate film thickness 25 μm, manufactured by Tokai Toyo Aluminum Sales Co., Ltd.) comprising aluminum foil and a polyethylene terephthalate film using a batch vacuum laminator (manufactured by Nichigo-Morton, Morton-724). Lamination was performed under conditions of a temperature of 80°C, a time of 30 seconds, and a pressure of 0.3 MPa. Next, the support was peeled off, and a glass plate (length 76 mm, width 26 mm, thickness 1.2 mm, microslide glass) was further laminated onto the exposed polymer composition layer under the same conditions as above. The obtained laminate was stored in a constant temperature and humidity chamber set at a temperature of 85°C and a humidity of 85% RH for 500 hours, and an accelerated test was performed. The laminate was removed from the thermo-hygrostat and peeled at a 90° angle to the longitudinal direction of the aluminum foil at a pulling rate of 50 mm / min, and the adhesive strength (gf / cm) was measured. The adhesive strength obtained was evaluated according to the following criteria: ◯ (Good): Adhesive strength after accelerated testing was 300 gf / cm or more; Δ (Fair): Adhesive strength after accelerated testing was less than 300 gf / cm and 200 gf / cm or more; × (Poor): Adhesive strength after accelerated testing was less than 200 gf / cm.

[0127] <Method for evaluating water vapor barrier properties> A composite film "PET-Tuki AL1N30" (aluminum foil thickness: 30 μm, polyethylene terephthalate film thickness: 25 μm, manufactured by Tokai Toyo Aluminum Sales Co., Ltd.) comprising an aluminum foil and a polyethylene terephthalate film was prepared as a support film. A polymer composition layer was formed on the aluminum foil side of the support film in the same manner as in the polymer sheet manufacturing method in each Example and Comparative Example, except that this support film was used instead of a support. In this way, a test sheet comprising a support film and a polymer composition layer was obtained.

[0128] A 50 mm x 50 mm square glass plate made of alkali-free glass was prepared, washed with boiled isopropyl alcohol for 5 minutes, and dried at 150°C for 30 minutes or more.

[0129] Calcium was vapor-deposited onto one surface of the glass plate using a mask that covered the peripheral area 0 mm to 1 mm from the edge of the glass plate, thereby forming a calcium film (purity 99.8%) with a thickness of 200 nm on the central portion of one surface of the glass plate, excluding the peripheral area 0 mm to 1 mm from the edge of the glass plate.

[0130] In a nitrogen atmosphere, the polymer composition layer of the test sheet and the calcium film side of the glass plate were bonded together using a thermal laminator (Fujipla Lamipacker DAiSY A4 (LPD2325)) to obtain a laminate.

[0131] Generally, calcium becomes transparent when it comes into contact with water and becomes calcium oxide. Furthermore, in the evaluation sample, since the glass plate and aluminum foil have sufficiently high water vapor barrier properties, moisture usually migrates in the in-plane direction (perpendicular to the thickness direction) through the edge of the polymer composition layer and reaches the calcium film. Therefore, when moisture penetrates the evaluation sample, the calcium film gradually oxidizes from the edge and becomes transparent, and shrinkage of the calcium film is observed. Therefore, moisture penetration into the evaluation sample can be evaluated by measuring the sealing distance [mm] from the edge of the evaluation sample to the calcium film. Therefore, the evaluation sample containing the calcium film can be used as a model for a lead-containing electronic device.

[0132] First, the sealing distance X2 [mm] from the edge of the evaluation sample to the edge of the calcium film was measured using a microscope (Measuring Microscope MF-U, manufactured by Mitutoyo Corporation). Hereinafter, this sealing distance X2 may be referred to as the initial sealing distance X2.

[0133] Next, the evaluation sample was placed in a thermo-hygrostat chamber set at a temperature of 85°C and a humidity of 85% RH. When the sealing distance X1 (mm) between the end of the evaluation sample placed in the thermo-hygrostat chamber and the end of the calcium film increased by 0.1 mm from the initial sealing distance X2, the evaluation sample was removed from the thermo-hygrostat chamber. The time from when the evaluation sample was placed in the thermo-hygrostat chamber to when the evaluation sample was removed from the thermo-hygrostat chamber was calculated as the decrease start time t [hours]. This decrease start time t was calculated from the time T when the evaluation sample was placed in the thermo-hygrostat chamber. Ｐ１ From the time T, the sealing distance X1 [mm] between the end of the evaluation sample stored in the thermo-hygrostat and the end of the calcium film becomes "X2 + 0.1 mm". Ｐ２ corresponds to the time until

[0134] The sealing distance X1 and the decrease start time t were applied to the Fick's diffusion equation of formula (1) to calculate a constant K as a water vapor barrier property parameter.

[0135]

[0136] Using the obtained constant K, the water vapor barrier property, which is the ability of the polymer composition layer to suppress the penetration of moisture, was evaluated according to the following criteria. The smaller the value of the constant K, the higher the water vapor barrier property. "h" means "hours."

[0137] (Criteria for water vapor barrier properties) ◯ (Good): Constant K is 0.0075 cm / h ０．５ Less than △ (Acceptable): Constant K is 0.0075 cm / h ０．５ Above, 0.025cm / h ０．５ x (bad): Constant K is less than 0.025 cm / h ０．５ That's all.

[0138]

[0139]

[0140] The results in Table 1 show that the polymer sheets of Examples 1 to 15 were all good in the evaluations of film-forming ability, adhesive strength, and water vapor barrier property. On the other hand, the results in Table 2 show that in Comparative Example 1, in which component (A) was not used, film formation was impossible and no polymer sheet was obtained in the first place, the polymer sheet of Comparative Example 2, in which component (B) was not used, was poor in the evaluation of water vapor barrier property, the polymer sheet of Comparative Example 3, in which component (C) was not used, was poor in the evaluation of adhesive strength, and the polymer sheet of Comparative Example 4, in which the content of component (A) was less than 12 mass%, was poor in the evaluation of adhesive strength.

[0141] The polymer composition of the present invention can form a polymer composition layer (as an encapsulant) that exhibits high water vapor barrier properties and does not show a decrease in adhesion to a backsheet in an accelerated test, and can be suitably used for encapsulating electronic devices that are sensitive to moisture, such as organic EL devices, organic light-emitting diodes (OLEDs), solar cells, and organic thin film transistors (OTFTs).

[0142] This application is based on patent application No. 2024-052476 filed in Japan, the contents of which are incorporated in their entirety herein.

Claims

1. A polymer composition containing the following components: (A) a low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group; (B) a water-absorbing filler; and (C) a high-molecular-weight styrene-olefin polymer that does not contain a double bond in the olefin moiety, wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 12% by mass or more relative to 100% by mass of the non-volatile content of the polymer composition.

2. The polymer composition according to claim 1, further comprising (D) a low molecular weight olefin polymer other than (A).

3. The polymer composition according to claim 1, further comprising (E) a high molecular weight olefin polymer other than (C).

4. The polymer composition according to claim 1, wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group has a number-average molecular weight of 950 to 20,000.

5. The polymer composition according to claim 1, wherein the content of (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is 16 to 24% by mass relative to 100% by mass of the nonvolatile content of the polymer composition.

6. The polymer composition according to claim 1, wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is an acid anhydride-modified low-molecular-weight olefin polymer.

7. The polymer composition according to claim 6, wherein (A) the low-molecular-weight olefin polymer having an acid anhydride group and / or a carboxyl group is a maleic anhydride-modified low-molecular-weight olefin polymer.

8. The polymer composition of claim 1, wherein (B) the water-absorbing filler is calcium oxide.

9. The polymer composition according to claim 1, wherein the median diameter of the water-absorbing filler (B) is 0.3 to 5 μm.

10. (B) The BET specific surface area of ​​the water-absorbing filler is 1 to 30 m ２ The polymer composition of claim 1, wherein the molecular weight of the polymer composition is 1 / g.

11. The polymer composition according to claim 1, wherein (C) the high molecular weight styrene-olefin polymer containing no double bonds in the olefin moiety has a number average molecular weight of more than 20,000 and not more than 5,000,000.

12. The polymer composition according to claim 1, wherein (C) the high molecular weight styrene-olefin polymer containing no double bonds in the olefin moiety contains no isoprene units.

13. The polymer composition according to claim 1, wherein (C) the high molecular weight styrene-olefin polymer containing no double bonds in the olefin moiety is a high molecular weight styrene-ethylene-ethylene-propylene-styrene copolymer containing no double bonds in the olefin moiety.

14. The polymer composition according to claim 1, wherein (C) the amount of styrene units in the high molecular weight styrene-olefin polymer containing no double bonds in the olefin moiety is 30% by weight or less based on the total of styrene units and olefin units.

15. A polymer sheet having a laminated structure comprising a polymer composition layer formed from the polymer composition of claim 1.

16. The polymer sheet of claim 15, which is used to encapsulate electronic devices.

17. An electronic device encapsulated with the polymer sheet of claim 15.

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