The problem of the present invention is to provide a novel polytetrafluoroethylene porous film having a small pore diameter, small film thickness, high porosity, and high strength, and a production method thereof.

The present invention provides a polytetrafluoroethylene porous film, wherein a bubble point in isopropyl alcohol (IPA) according to JIS K3832 is not less than 400 kPa, and a tensile strength based on JIS K6251 is not less than 50 MPa.

The problem of the present invention is to provide a novel polytetrafluoroethylene porous film having a small pore diameter, small film thickness, high porosity, and high strength, and a production method thereof.

The present invention provides a polytetrafluoroethylene porous film, wherein a bubble point in isopropyl alcohol (IPA) according to JIS K3832 is not less than 400 kPa, and a tensile strength based on JIS K6251 is not less than 50 MPa.

Improved battery separators, base films or membranes, batteries, cells, devices, systems, vehicles, and/or methods of making and/or using such separators, films or membranes, batteries, cells, devices, systems, vehicles, and/or methods of enhancing battery or cell charge rates, charge capacity, and/or discharge rates, and/or methods of improving batteries, systems including such batteries, vehicles including such batteries and/or systems, and/or the like; biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators with improved charge capacities and the related methods and methods of manufacture, methods of use, and the like; flat sheet membranes, liquid retention media; dry process separators; biaxially stretched separators; dry process biaxially stretched separators having a thickness range between about 5 μm and 50 μm, preferably between about 10 μm and 25 μm, having improved strength, high porosity, and unexpectedly and/or surprisingly high charge capacity, such as, for example, high 10 C rate charge capacity; separators or membranes with high charge capacity and high porosity, excellent charge rate and/or charge capacity performance in a rechargeable and/or secondary lithium battery, such as a lithium ion battery, for high power and/or high energy applications, cells, devices, systems, and/or vehicles, and/or the like; single or multiple ply or layer separators, monolayer separators, trilayer separators, composite separators, laminated separators, co-extruded separators, coated separators, 1 C or higher separators, at least 1 C separators, batteries, cells, systems, devices, vehicles, and/or the like; improved microporous battery separators for secondary lithium batteries, improved microporous battery separators with enhanced or high charge (C) rates, discharge (C) rates, and/or enhanced or high charge capacities in or for secondary lithium batteries, and/or related methods of manufacture, use, and/or the like, and/or combinations thereof are disclosed or provided.

A polymer thin film includes polyvinylidene fluoride (PVDF) and is characterized by a Young's modulus along an in-plane dimension of at least 4 GPa, an electromechanical coupling factor (k.sub.31) of at least 0.1 at room temperature. A method of manufacturing such a polymer thin film may include forming a polymer composition into a polymer thin film, applying a tensile stress to the polymer thin film along at least one in-plane direction and in an amount effective to induce a stretch ratio of at least approximately 5 in the polymer thin film, and applying an electric field across a thickness dimension of the polymer thin film. Annealing and poling steps may separately or simultaneously accompany and/or follow the act of stretching of the polymer thin film.

A feed device for automatically feeding a material web from a first stretching unit to a second stretching unit is disclosed having a conveying device configured to transfer at least one strip of the material web that exits the first stretching unit to a transport device of the second stretching unit.

Disclosed are compositions and methods for multilayer films, which, in one embodiment may comprise a core layer comprising at least 50 wt. % of high-density polyethylene. Further, the multilayer film may include a first skin layer consisting essentially of one or more ethylene-propylene copolymers. Further still, the multilayer film may include a second skin layer consisting essentially of one or more ethylene-propylene-butylene terpolymers. And yet further, the multilayer film may be oriented in at least one direction, and at least two layers of the multilayer film are coextruded.

In a gas-barrier aluminum deposition film according to one embodiment of the present invention, a seed coating layer containing functional groups of at least one type selected from among a hydroxyl group (—OH), an amine group (—NH), and a carboxylic acid group (—COOH) is formed on a thermoplastic plastic base film to form a seed molecular layer that enables uniform deposition of aluminum, such as AlOx or AlNx, through chemical reaction, on a surface of the coating layer, with aluminum atoms vaporized at the initial stage of aluminum deposition, thereby inducing uniform deposition of an aluminum layer to be subsequently deposited. Therefore, it is possible to provide a deposited film having superior oxygen and water vapor barrier properties compared to existing aluminum deposition films.

A method of producing high modulus and strength polymer materials includes compressive rolling a semicrystalline polymer material in at least two different axial directions of the material; and axially orienting at least a portion of the compressive rolled material to a draw ratio less than the ultimate elongation or the elongation % at break of the material.

A biaxially oriented polyester reflection film according to an embodiment of the present invention includes: a core layer having a plurality of voids, and containing homo-polyester, copolymer polyester, a resin incompatible with polyester, and inorganic particles; and a skin layer formed at least one surface of the core layer, and containing homo-polyester, copolymer polyester, and inorganic particles, wherein the biaxially oriented polyester reflection film is formed to have a plurality of light focusing structures, each of which has a concave center portion, and which are arranged in a grid pattern.

Provided is a porous polytetrafluoroethylene membrane in which an absolute value of a difference in lightness between one principal surface and the other principal surface is 1.0 or more, where the lightness is lightness L* of CIE 1976 (L*, a*, b*) color space specified in JIS Z8781-4: 2013. The porous polytetrafluoroethylene membrane may be colored black or gray. The porous polytetrafluoroethylene membrane provided can have properties with a reduced coloring-induced deterioration.