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.

A blower nozzle is a blower nozzle that blows out the air to a film being conveyed, and that includes an internally installed portion that is provided near a position where the air is blown out, inside the blower nozzle, and that has inclined surfaces inclined with respect to a virtual plane passing through an opening surface of an opening of the blower nozzle, the opening surface being a surface from which the air is blown out, the inclined surfaces being inclined in a manner being closer to each other toward the virtual plane.

To provide a biaxially stretched polyester resin film that has excellent properties equal to or better than those of biaxially stretched polyester film that does not use recycled raw material, and in particular that has an excellent flexural resistance in low-temperature environments. A biaxially stretched polyester resin film that characteristically satisfies both of the following properties (1) and (2): (1) in differential scanning calorimetry (DSC), after heating from 25° C. to 300° C. at a heating rate of 20° C./minute and holding for 10 minutes at 300° C., the temperature of crystallization during cooling at a cooling rate of 40° C./minute is 160° C. to 180° C.; and (2) the number of pinholes after the execution of 200 repetitive cycles of a flexural fatigue test in a −10° C. atmosphere using a Gelbo Flex Tester is not more than 10/500 cm.sup.2.

A biaxially stretched polyester film and a method for producing the same are provided. The biaxially stretched polyester film includes a polyester resin base layer and a matte layer. The polyester resin base layer includes: (1) 50 to 95 wt % of a polyester resin base material, and an intrinsic viscosity of the polyester resin base material being between 0.5 and 0.8 dL/g; and (2) 0.01 to 5 wt % of a high viscosity polyester resin material, and an intrinsic viscosity of the high viscosity polyester resin material being between 0.9 and 1.1 dL/g. The matte layer includes: (1) 50 to 95 wt % of a polyester resin matrix material, and an intrinsic viscosity of the polyester resin matrix material being between 0.5 and 0.8 dL/g; and (2) 0.3 to 40 wt % of a plurality of filler particles, and the filler particles having an average particle size of between 0.15 μm and 10 μm.

The present patent application relates to a method of manufacturing a multilayered composite film comprising a step of co-extruding at least three layers (a), (b) and (c), of which the layer (a) forms an outward surface of the composite film; the layer (c) forms a surface of the composite film facing or coming in contact with a good to be packaged; and the layer (b) is disposed between the layer (a) and the layer (c). Further, the method includes a step of biaxial orientation of the composite film thus co-extruded. Therein, the layer (a) contains or consists of a thermoplastic resin. The layer (b) contains or consists of a polyvinylidene chloride (PVdC) resin. The layer (c) contains or consists of a resin, preferably sealable, in particular heat-sealable resin. Therein, any crosslinking of the composite film by means of radioactive radiation, in particular by means of beta, gamma, X-ray and/or electron irradiation, is omitted during the manufacturing of the composite film and/or thereafter.

There is provided a multilayer structure comprising at least a barrier resin layer (X) and an inorganic barrier layer (Y) with a thickness of 500 nm or less which is adjacent to the barrier resin layer (X), wherein the layer (X) is made of a resin composition (x) comprising an ethylene-vinyl alcohol copolymer (A) and a polyamide (B) in a mass ratio (A/B) of 55/45 to 98/2, and the ethylene-vinyl alcohol copolymer (A) has an ethylene content of 20 to 46 mol % and a saponification degree of 90 mol % or more. Thus, there can be provided a multilayer structure having excellent gas barrier properties and appearance even after being subjected to stretching process or retorting process followed by bending process, and a packaging material for retort therewith.

The present disclosure provides a multilayer film comprising a resin composition layer containing an ethylene-vinyl alcohol copolymer with an ethylene unit content of 20 mol% or more and 60 mol% or less and an ethylene-vinyl alcohol copolymer with an ethylene unit content being more than the ethylene-vinyl alcohol copolymer, and a thermoplastic resin layer.

The invention provides a polyolefin-based resin film formed from a polypropylene-based resin composition and containing, in a total of 100 parts by weight of the polypropylene-based resin composition, 20-95 parts by weight of a propylene-α olefin random copolymer containing a metallocene-based olefin polymerization catalyst; 0-75 parts by weight of a propylene-α olefin random copolymer containing a Ziegler-Natta-based olefin polymerization catalyst; and 5-15 parts by weight of at least one type of an elastomer selected from the group consisting of an ethylene-butene copolymer elastomer, a propylene-butene copolymer elastomer, and an ethylene-propylene copolymer elastomer, wherein a heat shrinkage ratio in a direction in which a heat shrinkage ratio is larger among a longitudinal direction and a width direction of the polyolefin-based resin film is 1-10%, and an orientation coefficient ΔNx in an x-axis direction calculated from a refractive index of the polyolefin-based resin film is 0.0130-0.0250.

A wide microporous film comprises one or more layers comprising a polyolefin; wherein the film has a width of a least 40 inches, at least 45 inches, at least 50 inches, at least 55 inches, at least 60 inches, at least 65 inches, or at least 70 inches.

An integral polymer grid with a plurality of interconnected, oriented polyethylene terephthalate strands and an array of openings therein is made from a polyethylene terephthalate sheet-like starting material having holes or depressions therein that form the openings when the sheet-like material is uniaxially or biaxially stretched. The grid has a higher tensile strength to weight ratio and a higher creep reduced strength to weight ratio than corresponding ratios associated with a grid made from a non-polyethylene terephthalate starting material.