JP-2026075951-A - Resin sheets and diaphragms for filter presses

Abstract

【assignment】 We propose a sheet that can ensure tensile strength, elongation at break, flexural modulus, and fatigue resistance, while also suppressing uneven crystallization during sheet formation, resulting in a smooth sheet, i.e., a sheet with reduced surface irregularities. [Solution] A resin sheet comprising a copolymer (A) containing butene-1 and at least one α-olefin other than butene-1 as copolymer components, and a polyolefin polymer (B) having a long-chain branched structure, wherein the ratio of the mass content of copolymer (A) to the mass content of polyolefin polymer (B) is copolymer (A):polyolefin polymer (B) = 50:50 to 99:1, and the melt extension viscosity at 180°C and a strain rate of 5/sec is 6000 Pa·s or more. [Selection Diagram] None

Inventors

• 古谷 小春
• 佐藤 信行
• 大久保 大介

Assignees

• 三菱ケミカルインフラテック株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (5)

1. The material comprises a copolymer (A) containing butene-1 and at least one α-olefin other than butene-1 as copolymer components, and a polyolefin polymer (B) having a long-chain branched structure, wherein the ratio of the mass content of copolymer (A) to the mass content of polyolefin polymer (B) is copolymer (A):polyolefin polymer (B) = 50:50 to 99:1. A resin sheet having a melt extension viscosity of 6000 Pa·s or more at 180°C and a strain rate of 5/sec.
2. The resin sheet according to claim 1, wherein at least one α-olefin other than butene-1 is one of ethylene, propylene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-tetradecene, and 1-octadecene.
3. The resin sheet according to claim 1, wherein at least one α-olefin other than butene-1 is ethylene or propylene.
4. The resin sheet according to claim 1, wherein the polyolefin polymer (B) having a long-chain branched structure is polypropylene.
5. A diaphragm for a filter press, made of a resin sheet as described in any one of claims 1 to 4.

Description

This invention relates to a diaphragm used in a filter press, and a resin sheet that can be suitably used with said diaphragm. A filter press (pressure dewatering machine) is a device used to separate solid matter mixed in a liquid, and is used, for example, in the processing of concentrated liquids in food factories and in the dewatering and drying of sludge. A filter press has a configuration in which a "diaphragm" is arranged in a filtration chamber surrounded by filter plates, with the diaphragm acting as a counterpart to the filter plate. The material to be dewatered, such as cake or sludge, is filled into the diaphragm and contained therein. A fluid such as air is then injected under pressure between the filter plates and the diaphragm, compressing the material and allowing the squeezed-out water to be discharged outside the filtration chamber, thereby dewatering the material. A diaphragm is a membrane that undergoes displacement in response to pressure, and conventionally, natural rubber (NR), styrene rubber (SBR), and synthetic rubbers such as ethylene propylene rubber (EPT) have been the main materials used for diaphragms. However, in recent years, sheets made of elastomers, particularly low-odor thermoplastic elastomers, have been used from the standpoint of elasticity, tensile strength, water resistance, and low odor. For example, Patent Document 1 discloses a polyolefin-based elastomer for use in diaphragms, which is a mechanically blended and partially crosslinked polyolefin-based polymer and ethylene-propylene copolymer rubber. Patent Document 2 discloses a filter press diaphragm used for solid-liquid separation, which is composed of a polyethylene-butene-based thermoplastic elastomer or a polyether-ester-based thermoplastic elastomer. Patent Document 3 discloses a filter press diaphragm made of a crystalline thermoplastic synthetic resin, which is a partially crosslinked polyolefin thermoplastic elastomer, or a composition obtained by mechanically blending a polyolefin polymer with ethylene-propylene copolymer rubber or ethylene-propylene-non-conjugated diene copolymer rubber. Patent Document 4 discloses a resin composition for use in diaphragms for filter press applications, comprising at least one material selected from the group consisting of polyurethane elastomer, polyester elastomer, and polyamide elastomer in an amount of 59.9 to 90% by volume, a processing aid containing polytetrafluoroethylene in an amount of 0.1 to 5% by volume, and a filler in an amount of 5 to 40% by volume, wherein the resin composition has a thermal conductivity of 0.4 to 2.0 W/m·°C at room temperature. Patent Document 5 discloses a diaphragm for filter press applications, comprising a resin composition containing 10 to 70% by weight of a polyolefin-based thermoplastic elastomer and 90 to 30% by weight of a recycled polypropylene-based resin. Patent Document 6 discloses a thermoplastic elastomer in a mixed state of a propylene-ethylene copolymer (A) having a polymerization ratio of 99-50% propylene and 1-50% ethylene, and an olefin copolymer rubber (B) such as ethylene-propylene copolymer rubber or ethylene-propylene-non-conjugated diene copolymer rubber, or a partially crosslinked thermoplastic elastomer obtained by partially crosslinking this mixture with a crosslinking agent, characterized in that it contains 10-60% propylene-ethylene copolymer (A) and 30-10% olefin copolymer rubber (B) by weight. Special Publication No. 3-50562Japanese Patent Application Publication No. 7-88306Patent No. 3547232Patent No. 3914403Japanese Patent Publication No. 2000-279709Patent No. 3194265 The following describes an example of an embodiment of the present invention. However, the present invention is not limited to the embodiment described below. <Resin sheet of the present invention> An example of an embodiment of the present invention (referred to as the "present invention resin sheet") is a resin sheet comprising a copolymer (A) containing butene-1 and at least one α-olefin other than butene-1 (also referred to as "other α-olefin") as copolymer components, and a polyolefin polymer (B) having a long-chain branched structure. In this invention, "resin sheet" refers to a sheet whose main material is resin, i.e., a polymer. The term "main material" refers to either the matrix component of the sheet, or the component with the highest mass proportion among the components constituting the sheet. By adding a polyolefin polymer (B) having a long-chain branched structure to copolymer (A), the melt tension of the resin sheet can be improved, resulting in a sheet with excellent mechanical strength and free from crystallization irregularities and surface irregularities. The resin sheet of the present invention preferably has copolymer (A) as its main component resin. By including copolymer (A) as the main component resin, the resin sheet of the present invention can obtain, for example, the mechanical strength, flexibility, fatigue res