Methods for increasing transparency of a nanofiber sheet to many wavelengths of radiation, including those wavelengths within the visible spectrum, are described. These techniques include straining a nanofiber sheet so as to increase its width.

A resin composition having a high blending proportion of an inorganic substance powder that can produce a stretched sheet having an excellent elongation property and high whiteness and opacity. A resin composition for producing a stretched sheet including: a first thermoplastic resin, a second thermoplastic resin different from the first thermoplastic resin, and an inorganic substance powder, in which a mass proportion of the first thermoplastic resin and the inorganic substance powder is 50:50 to 10:90, a content of the second thermoplastic resin is 1% by mass or more and 7% by mass or less relative to a total amount of the first thermoplastic resin and the inorganic substance powder, and the second thermoplastic resin is low stereoregular polypropylene.

Techniques for producing at least one PLA strip involve: a) providing a strip-shaped extruded PLA film, b) heating the PLA film provided according to step a) to a temperature in the range from 40 to 70° C., c) cutting the PLA film heated according to step b) into the at least one PLA strip, and d) stretching the PLA film cut according to step c).

Techniques for producing at least one PLA strip involve: a) providing a strip-shaped extruded PLA film, b) heating the PLA film provided according to step a) to a temperature in the range from 40 to 70° C., c) cutting the PLA film heated according to step b) into the at least one PLA strip, and d) stretching the PLA film cut according to step c).

An apparatus for producing at least one PLA tape includes a heating device for heating a tapelike extruded PLA film. The apparatus further includes a slitting device for slitting the PLA film heated by means of the heating device into the at least one PLA tape. The apparatus further includes a control unit which is configured to control the heating device in such a way that the PLA film is heated by the heating device to a PLA temperature in the range from 40 to 70° C. The apparatus further includes a drawing device downstream of the slitting device.

An apparatus for producing at least one PLA tape includes a heating device for heating a tapelike extruded PLA film. The apparatus further includes a slitting device for slitting the PLA film heated by means of the heating device into the at least one PLA tape. The apparatus further includes a control unit which is configured to control the heating device in such a way that the PLA film is heated by the heating device to a PLA temperature in the range from 40 to 70° C. The apparatus further includes a drawing device downstream of the slitting device.

Provided is a film for a capacitor that can improve dielectric strength retention at high temperatures and can also improve metal vapor deposition properties and formability. The film for a capacitor contains a hydrogenated dicyclopentadiene ring-opened polymer that is crystalline and has a heat shrinkage ratio of not less than 0.01% and not more than 1.0% when heated at 200 C. for 10 minutes, a plane orientation factor of 0.01 or more, a density of 1.0310.sup.6 g/m.sup.3 or more, and a thickness of 15.0 m or less.

The stretchable porous film of the present invention includes voids in a surface thereof, in which: the stretchable porous film has an air permeability measured with an Oken-type air permeability meter of less than 99,999 sec/100 cc; the stretchable porous film has such an extending direction that an air permeability measured with the Oken-type air permeability meter in a state in which the stretchable porous film is extended by 100% becomes less than 60,000 sec/100 cc; and the stretchable porous film has such a pulling direction that when, in a hysteresis test, the stretchable porous film is pulled from a width of 20 mm and an inter-chuck distance of 30 mm to an inter-chuck distance of 60 mm at a pulling speed of 50 mm/min and held for 1 minute, and then the pulling of the inter-chuck distance is released, a residual strain becomes 10 mm or less.

The stretchable porous film of the present invention includes voids in a surface thereof, in which: the stretchable porous film has an air permeability measured with an Oken-type air permeability meter of less than 99,999 sec/100 cc; the stretchable porous film has such an extending direction that an air permeability measured with the Oken-type air permeability meter in a state in which the stretchable porous film is extended by 100% becomes less than 60,000 sec/100 cc; and the stretchable porous film has such a pulling direction that when, in a hysteresis test, the stretchable porous film is pulled from a width of 20 mm and an inter-chuck distance of 30 mm to an inter-chuck distance of 60 mm at a pulling speed of 50 mm/min and held for 1 minute, and then the pulling of the inter-chuck distance is released, a residual strain becomes 10 mm or less.

The present disclosure relates to how to engineer reversible elasticity in thin films and/or layers and/or substrates, using a repeated Y-shaped motif, which is cut out through the film and/or layer and/or substrate. As an example, using a 75 m thick polyimide (PI) foil, macroscopic dog-bone shaped structures with a range of geometrical parameters of the Y shape have been prepared according to an embodiment of the present disclosure. The tensile strain response of the film at its point of fracture was then recorded. The structures were also confirmed using finite element modeling. Upon stretching, the PI ligaments locally deflect out of plane, allowing the foil to macroscopically stretch.