Multilayer retardation film and method for producing same
US-2015378079-A1 · Dec 31, 2015 · US
Method for producing multi-layer, microporous polyolefin membrane
US9492965B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9492965-B2 |
| Application number | US-8967606-A |
| Country | US |
| Kind code | B2 |
| Filing date | Oct 19, 2006 |
| Priority date | Oct 19, 2005 |
| Publication date | Nov 15, 2016 |
| Grant date | Nov 15, 2016 |
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Abstract
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A multi-layer, microporous polyolefin membrane comprising a polypropylene layer and a polyethylene resin layer and having well-balanced permeability, mechanical strength, heat shrinkage resistance, shutdown properties and meltdown properties can be obtained by (1) forming a sheet comprising a gel-like polypropylene layer containing a membrane-forming solvent or a polypropylene layer containing no membrane-forming solvent and a gel-like polyethylene resin layer containing a membrane-forming solvent, stretching the sheet at two-stage temperatures, and then removing the membrane-forming solvent, or (2) forming a gel-like polypropylene sheet containing a membrane-forming solvent or a polypropylene sheet containing no membrane-forming solvent, and a gel-like polyethylene resin sheet containing a membrane-forming solvent, stretching them at two-stage temperatures, removing the membrane-forming solvent, and then laminating the resultant microporous polypropylene membrane and the resultant microporous polyethylene membrane.
First claim
Opening claim text (preview).
What is claimed is: 1. A method for producing a multi-layer, microporous polyolefin membrane comprising a microporous polypropylene layer and a microporous polyethylene resin layer, comprising the steps of simultaneously extruding a melt blend of 20 to 55% by mass of polypropylene and 45 to 80% by mass of a membrane-forming solvent and a melt blend of 20 to 55% by mass of a polyethylene resin and 45 to 80% by mass of a membrane-forming solvent through a die to form a laminar extrudate, cooling the laminar extrudate to provide a gel-like laminate sheet, first stretching the gel-like laminate sheet biaxially at a temperature of −20° C. or higher and lower than +90° C., conducting re-stretching biaxially at a temperature of 90 to 135° C., and removing the membrane-forming solvent from the stretched gel-like laminate sheet, wherein said polyethylene resin is a composition of ultra-high molecular weight polyethylene having molecular weight of 5×10 5 or higher and another polyethylene having molecular weight of 1×10 4 or more and less than 5×10 5 , and wherein the content of said ultra-high molecular weight polyethylene is 10 to 80% by mass based on 100% by mass of said polyethylene composition. 2. The method for producing a multi-layer, microporous polyolefin membrane according to claim 1 , wherein the temperature of the first stretching is 60° C. or higher and lower than +90° C.
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Classifications
comprising layers of only organic material and layers containing inorganic material · CPC title
Tensile strength · CPC title
Acrylic resins · CPC title
Polyolefins · CPC title
Fluorocarbon polymers · CPC title
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- What does patent US9492965B2 cover?
- A multi-layer, microporous polyolefin membrane comprising a polypropylene layer and a polyethylene resin layer and having well-balanced permeability, mechanical strength, heat shrinkage resistance, shutdown properties and meltdown properties can be obtained by (1) forming a sheet comprising a gel-like polypropylene layer containing a membrane-forming solvent or a polypropylene layer containing …
- Who is the assignee on this patent?
- Takita Kotaro, Kikuchi Shintaro, Toray Battery Separator Film
- What technology area does this patent fall under?
- Primary CPC classification B29C55/023. Mapped technology areas include Operations & Transport.
- When was this patent published?
- Publication date Tue Nov 15 2016 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 8 related publications on this page (citations in our corpus or others sharing the same primary CPC).