JP-7856095-B2 - Multilayer sheet and method for manufacturing the same

Inventors

• 今堀 誠
• 宮村 健太郎
• 岩槻 圭悟
• 津田 隆

Assignees

• 東亞合成株式会社

Dates

Publication Date

20260511

Application Date

20220427

Priority Date

20210428

Claims (9)

1. A base layer (A) is a thermoplastic resin containing 40 to 99.9% by mass of polyphenylene ether (a1), 0 to 59.9% by mass of polystyrene (a2), and an amino group-containing polymer (a3), An adhesive layer (B) containing an acid-modified polyolefin, A multilayer sheet containing [a specific component].
2. The multilayer sheet according to claim 1, wherein the content of the amino group-containing polymer (a3) in the base layer (A) is 2 to 40% by mass.
3. The softening point of the base layer (A) is 175°C or higher. The softening point is the temperature at which the tanΔ value is highest when the temperature is raised from room temperature to 250°C at a frequency of 1 Hz and a heating rate of 2°C/min, as determined using a tensile viscoelastic device. This is the multilayer sheet according to claim 1.
4. The multilayer sheet according to claim 1, wherein the storage modulus of the substrate layer (A) at 160°C is 500 MPa or more, as measured by heating from room temperature to 250°C under the conditions of a tensile viscoelasticity measuring device with a frequency of 1 Hz and a heating rate of 2°C/min.
5. The multilayer sheet according to claim 1, wherein the amino group-containing polymer (a3) of the base layer (A) contains polystyrene chains having amino groups at their ends.
6. The multilayer sheet according to claim 5, wherein the amino group-containing polymer (a3) of the base layer (A) is a styrene-diene-styrene block copolymer.
7. The multilayer sheet according to claim 1, wherein the acid-modified polyolefin is a maleic anhydride-modified polyolefin.
8. A multilayer sheet according to any one of claims 1 to 7, wherein the base layer (A) has a thickness of 50 to 300 μm and the adhesive layer (B) has a thickness of 10 to 100 μm.
9. A method for producing a multilayer sheet, comprising the step of bringing a base layer (A), which is a thermoplastic resin containing 40 to 99.9% by mass of polyphenylene ether (a1), 0 to 59.9% by mass of polystyrene (a2), and an amino group-containing polymer (a3), into contact with an adhesive layer (B) containing an acid-modified polyolefin in a molten state at 160°C or higher.

Description

The present invention relates to a multilayer sheet with excellent adhesive properties and heat resistance, which can be used for bonding and sealing various parts and can be used as a sheet-like material itself, and to a method for manufacturing the same. In recent years, hot-melt adhesive compositions have come to be used as adhesive films or sheets (hereinafter collectively referred to as "adhesive components") in chemical batteries such as lithium-ion batteries and fuel cells incorporated into laptop computers, smartphones, tablets, and automobiles, as well as in physical batteries such as solar cells and capacitors. It is known that relatively good adhesive strength can be obtained by using a hot-melt adhesive composition mainly composed of acid-modified olefin-based thermoplastic resins (hereinafter also referred to as "acid-modified polyolefins") to bond metal substrates such as iron, aluminum, titanium, and other metals, and their alloys, which are used as base materials for the components of these batteries. In battery applications, hot-melt adhesive compositions are required to possess not only adhesive strength but also durability against the battery's constituent materials. In lithium-ion batteries, lithium hexafluorophosphate, used as the electrolyte, may react with water to generate hydrofluoric acid. In fuel cells, acids such as hydrofluoric acid may be generated from the electrolyte membrane, a component of the battery, thus requiring acid resistance. Furthermore, lithium-ion batteries require durability against ethylene carbonate or diethyl carbonate used as a solvent for the electrolyte, while nickel-metal hydride batteries require durability against strong alkaline aqueous solutions. In addition, fuel cells circulate a cooling liquid containing ethylene glycol or propylene glycol inside the battery to cool the battery that generates heat during power generation, thus requiring durability against ethylene glycol and the like. Patent Document 1 discloses a resin composition comprising 50 to 99% by mass of a low-viscosity propylene-based polymer satisfying specific properties and 1 to 50% by mass of an acid-modified propylene-based elastomer satisfying specific properties, as well as a hot-melt adhesive containing the resin composition. This adhesive exhibits excellent adhesion to polyolefin-based substrates while also having excellent adhesion to metal substrates. Patent Document 2 describes acid-modified polypropylene as an adhesive between metal and nylon-based resins. By laminating acid-modified polyolefin adhesive films or sheets onto a substrate layer to form a multilayer sheet, it is possible to obtain even higher-performance and more functional adhesive components. Engineering plastics with excellent rigidity and heat resistance are used for the substrate layer of this multilayer sheet. By using acid-modified polyolefin adhesives in such multilayer sheets, strength, rigidity, gas barrier properties, chemical resistance, acid/alkali resistance, and heat resistance are improved, making them suitable for applications requiring durability, such as the lithium-ion batteries and fuel cells mentioned above. Furthermore, using multilayer sheets as adhesive components in lithium-ion batteries and fuel cells reduces the number of constituent components and parts, leading to cost reduction and improved productivity. As engineering plastics used as substrates for multilayer sheets, polyethylene naphthalate, heat-resistant polyolefins such as cycloolefin polymers, polyphenylene ether alloys, and aromatic polyamide resins have been used in terms of heat resistance, rigidity, dimensional stability, and cost. For example, Patent Document 3 describes a laminated sheet for sealing electronic equipment, in which a first sheet and a second sheet are laminated, characterized in that the first sheet contains an acid-modified polyolefin thermoplastic resin, the second sheet has a higher melting point than the first sheet, and the peel strength of the second sheet relative to the first sheet at 25°C is 0.5 to 10.0 [N/15 mm]. Patent Document 3 describes polyethylene naphthalate as a specific example of the second sheet. Japanese Patent Publication No. 2013-060521Japanese Patent Publication No. 2017-109613International Publication No. 2011/013389 This is a calibration curve for converting the absorbance ratio of ethylene units to propylene units into a mass ratio. The multilayer sheet of the present invention comprises a base layer (A) containing polyphenylene ether (a1) and an adhesive layer (B) containing acid-modified polyolefin. The base layer (A) is an intermediate layer or a surface layer, and the adhesive layer (B) is a surface layer. Here, the surface layer is a layer located on either the upper surface or the lower surface, and the intermediate layer is a layer other than the surface layer. If the adhesive layer (B) is provided on only one of the surface layers, the intermediate layer does not need t