A multilayered stretched polyamide film which is biaxially stretched, and comprises three layers composed of a polyamide resin composition and comprising layer B as an easily adhesive layer, layer A as a base layer, and layer C as an easily slippery layer in this order, wherein the film satisfies the following (1) to (4); (1) the layer A contains 50 to 90% by mass of polyamide 6 and 10 to 50% by mass of a polyamide 6 copolymer in which a ratio of a copolymerization component in the copolymer is 3 to 35% by mass; (2) the layer B contains 0 to 40% by mass of polyamide 6 and 60 to 100% by mass of the polyamide 6 copolymer in which a ratio of the copolymerization component in the copolymer is 3 to 35% by mass; (3) the layer C contains 70% by mass or more of polyamide 6 and 0.05 to 1% by mass of fine particles having an average diameter of 0.1 to 10 μm; (4) the film has tensile strength at break of 150 MPa or more both in MD direction and TD direction; and (5) the film has laminate strength of 3.3 N/15 mm or more.

A biaxially oriented polyester film having the following physical property is provided: when cooled from the molten state at a cooling rate of 20° C./min, an observed recrystallization temperature is 175° C.-200° C. The biaxially oriented polyester film is formed by a thick sheet before bidirectional stretching that is melted and extruded by an extruder and then cooled and formed on a casting roll. The thick sheet before stretching having the following physical property as analyzed by differential scanning calorimetry: a crystallization rate is less than 10%.

A biaxially oriented polyester film having the following physical property is provided: when cooled from the molten state at a cooling rate of 20° C./min, an observed recrystallization temperature is 175° C.-200° C. The biaxially oriented polyester film is formed by a thick sheet before bidirectional stretching that is melted and extruded by an extruder and then cooled and formed on a casting roll. The thick sheet before stretching having the following physical property as analyzed by differential scanning calorimetry: a crystallization rate is less than 10%.

A monolayer multi-axial integral geogrid suitable for stabilizing aggregate includes a plurality of interconnected oriented strands and partially oriented junctions forming a repeating pattern of outer hexagons having an array of openings therein. Oriented ribs extending inwardly from each of said outer hexagons support and surround a smaller inner hexagon having oriented strands thus forming a plurality of trapezoidal openings and a single hexagonal opening. The oriented strands and partially oriented junctions of the outer hexagons form a plurality of linear strong axis strands that extend continuously throughout the entirety of the geogrid and form additional triangular openings. The geogrid thus includes three different repeating geometric shapes. The inner hexagons preferably also can move up and down, out of the plane of the geogrid. The multi-axial integral geogrid thus provides a geometry that can better engage with, confine and stabilize a greater variety and quality of aggregates.

A monolayer multi-axial integral geogrid suitable for stabilizing aggregate includes a plurality of interconnected oriented strands and partially oriented junctions forming a repeating pattern of outer hexagons having an array of openings therein. Oriented ribs extending inwardly from each of said outer hexagons support and surround a smaller inner hexagon having oriented strands thus forming a plurality of trapezoidal openings and a single hexagonal opening. The oriented strands and partially oriented junctions of the outer hexagons form a plurality of linear strong axis strands that extend continuously throughout the entirety of the geogrid and form additional triangular openings. The geogrid thus includes three different repeating geometric shapes. The inner hexagons preferably also can move up and down, out of the plane of the geogrid. The multi-axial integral geogrid thus provides a geometry that can better engage with, confine and stabilize a greater variety and quality of aggregates.

A method of making a multi-axial integral geogrid suitable for stabilizing aggregate includes providing a polymer sheet, providing a patterned plurality of holes or depressions in the polymer sheet, and biaxially orienting the polymer sheet having the patterned plurality of holes or depressions therein to provide a plurality of interconnected oriented strands and partially oriented junctions forming a repeating pattern of outer hexagons having an array of openings. Oriented ribs extending inwardly from each of the outer hexagons support and surround a smaller inner hexagon having oriented strands, thus forming a plurality of trapezoidal openings and a single hexagonal opening. The oriented strands and partially oriented junctions of the outer hexagons form a plurality of linear strong axis strands extending continuously throughout the geogrid and forming triangular openings. The method provides a geogrid having a geometry configured to engage with, confine, and stabilize a large variety and quality of aggregates.

A method of making a multi-axial integral geogrid suitable for stabilizing aggregate includes providing a polymer sheet, providing a patterned plurality of holes or depressions in the polymer sheet, and biaxially orienting the polymer sheet having the patterned plurality of holes or depressions therein to provide a plurality of interconnected oriented strands and partially oriented junctions forming a repeating pattern of outer hexagons having an array of openings. Oriented ribs extending inwardly from each of the outer hexagons support and surround a smaller inner hexagon having oriented strands, thus forming a plurality of trapezoidal openings and a single hexagonal opening. The oriented strands and partially oriented junctions of the outer hexagons form a plurality of linear strong axis strands extending continuously throughout the geogrid and forming triangular openings. The method provides a geogrid having a geometry configured to engage with, confine, and stabilize a large variety and quality of aggregates.

A microporous membrane is made by a dry-stretch process and has substantially round shaped pores and a ratio of machine direction tensile strength to transverse direction tensile strength in the range of 0.5 to 5.0. The method of making the foregoing microporous membrane includes the steps of: extruding a polymer into a nonporous precursor, and biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction stretching including a simultaneous controlled machine direction relax.

In some embodiments, the present invention is directed to an actuator which includes at least the following: a pre-stretched electro-active polymer film being pre-stretched in a single or biaxial planar directions; at least one first semi-stiff conductor attached to a first surface of the pre-stretched electro-active polymer film, wherein the first surface is parallel to the single or biaxial planar stretch directions; at least one second semi-stiff conductor attached to a second surface of the pre-stretched electro-active polymer film, wherein the second surface is opposite to the first surface; where the semi-stiff conductors are configured to: fix the pre-stretched electro-active polymer film in a pre-stretched state and allow the pre-stretched electro-active polymer film to expand; a pair of mechanical connectors coupled to each end of an active region of the pre-stretched electro-active polymer film.

In some embodiments, the present invention is directed to an actuator which includes at least the following: a pre-stretched electro-active polymer film being pre-stretched in a single or biaxial planar directions; at least one first semi-stiff conductor attached to a first surface of the pre-stretched electro-active polymer film, wherein the first surface is parallel to the single or biaxial planar stretch directions; at least one second semi-stiff conductor attached to a second surface of the pre-stretched electro-active polymer film, wherein the second surface is opposite to the first surface; where the semi-stiff conductors are configured to: fix the pre-stretched electro-active polymer film in a pre-stretched state and allow the pre-stretched electro-active polymer film to expand; a pair of mechanical connectors coupled to each end of an active region of the pre-stretched electro-active polymer film.