Provided is a biaxially oriented polypropylene film that has high stiffness, has excellent heat resistance at a high temperature of 150° C., easily maintains a bag shape when being made into a packaging bag, and has less pitch shift during printing or fewer wrinkles in a sealed portion when being heat-sealed. A biaxially oriented polypropylene film, wherein a stress at 5% elongation (F5) at 23° C. of the biaxially oriented polypropylene film is not lower than 40 MPa in a longitudinal direction and not lower than 160 MPa in a width direction, and a heat shrinkage rate at 150° C. of the biaxially oriented polypropylene film is not higher than 7% in the longitudinal direction and not higher than 16% in the width direction.

A lithium-ion battery separator with high-temperature resistance, a preparation method thereof and a lithium-ion battery prepared therefrom fall within the field of lithium-ion battery separators. The separator has a thickness of 3.5-30 μm, a porosity of 30-80%, an adjustable pore size of 20-2000 nm, a biaxial tensile strength of ≥50 MPa, an air permeability of ≤400 s/100 cc, and a breaking temperature of ≥160° C. The preparation method comprises the following steps: mixing, melting, and plasticizing 20%-60% of a polypropylene main material, 2%-10% of a solubilizer, 30%-80% of a solvent. 0.1%-5% of a nucleating aid and/or 0.1%-1% of an antioxidant, carrying out twin-screw extrusion, carrying out thermally induced phase separation to obtain a cast sheet, and carrying out cast sheet stretching, extraction, and post-treatment or directly carrying out extraction and post-treatment. The separator has the characteristics of high-temperature resistance, biaxial high strength, uniform pore size, high specific resistance.

The polyester film according to the embodiment achieves the elasticity required for a cover of a flexible display by increasing the rate of increase in stress in an initial stage of strain to a certain level or higher. As a result, it is possible to maintain the original characteristics when it is applied to a cover of a flexible display device and subjected to a plurality of repeated folding. Accordingly, the polyester film can be applied to a cover of a flexible display device, in particular, a foldable display device to exhibit excellent characteristics.

A Biaxially Oriented Polyethylene (BOPE) process uses a selected polyethylene having a medium density and a very broad molecular weight distribution. The use of this selected polyethylene facilitates stretching in the BOPE process in comparison to previously used polyethylene resins having a higher density and/or a narrower molecular weight distribution.

The invention provides a biaxially oriented polyester film having excellent impact strength and heat resistance and a method for producing same. The method comprises (A) melt-extruding a composition comprising polyester resin for which Tc−(Tg+Tm)/2 is 25−30° C. to obtain unstretched polyester resin composition sheet, which (B) is heated at Tg+5 (° C.) to Tg+40 (° C.) of the polyester resin and stretched in the machine direction at 2×-6× to obtain uniaxially oriented polyester resin composition film, which (C) is heated at Tc−46 (° C.) to Tc+25 (° C.) of the polyester resin and stretched in the transverse direction at 4×−8× to obtain biaxially oriented polyester resin composition film, which (D) undergoes relaxation at 3%-20% in the transverse direction as heated at Tm−40 (° C.) to Tm−5 (° C.) of the polyester resin.

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 comprising, consisting essentially of, or consisting of low-density polyethylene, optionally linear, and at least about 80 wt. % of high-density polyethylene, as well as a second skin layer comprising either: (i) one or more low-density polyethylenes, any or all of them optionally being linear; or (ii) one or more polypropylene-based copolymers. The multilayer film may be oriented in at least one direction.

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.

The present application discloses a bending-resistant polyester film and its production method thereof. The chemical structure of the bending-resistant polyester composition comprises monomers having elastic conformation. The film made from the composition of polyester of the present invention through production processes such as melt extrusion and biaxial drawing still has excellent flexibility and optical properties.

A microporous membrane wipe and a method of using such microporous membrane wipe are disclosed. The microporous membrane wipe may be uniaxially or biaxially oriented microporous membrane. The uniaxially or biaxially oriented microporous membrane may be made from one or more block and/or impact copolymers of polyethylene and/or polypropylene. A method of using such a microporous membrane wipe for skin oil blotting is also disclosed. Further disclosed is a method of using such a microporous membrane wipe for cleaning a surface for the removal of fingerprints, smudges and the like, where such surfaces may include, for example, eyeglasses, electronics, cell phones, displays, optical devices, camera lenses, microscope lenses and other precision optics, and/or the like.