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.

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 double-layer longitudinal wrapping mold is disclosed, including a base, a first longitudinal wrapping structure, a first pressing structure, a second longitudinal wrapping structure, a second pressing structure and a first necking structure. The first longitudinal wrapping structure is disposed on the base and has a first guide hole, a first outer layer wrapping hole and an inner layer wrapping hole. The first pressing structure is disposed on the base and has a first pressing hole and a second outer layer wrapping tape hole. The second longitudinal wrapping structure is disposed on the base and has a second guide hole and a third outer layer wrapping tape hole. The second pressing structure is disposed on the base and has a second pressing hole and a fourth outer layer wrapping tape hole. The first necking structure is disposed on the base and has a necking hole.

A method includes mixing a solvent with a dry cathode mixture to form a slurry. The dry cathode mixture includes a cathode active material, a conductive diluent, and a polymeric binder. The method further includes removing the solvent from the slurry to form a composition and calendering, in a first calendering step, the composition to form a sheet. The calendering the composition includes passing the composition between calender rollers.

A method and system for stretching a length of Teflon (PTFE) tubing where a mandrel is fully inserted therein requires firmly supporting and tensioning the PTFE tubing at ends thereof and grabbing the supported tubing at two adjacent locations at the center thereof and sliding and gripping with grippers from the center towards the two ends thereby stretching and pulling the length of PTFE tubing.

A method for producing a fluoropolymer, which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1), the polymer (1) including a polymerized unit derived from a monomer CX.sub.2═CY(—CZ.sub.2—O—Rf-A), wherein X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a C1-C40 fluorine-containing alkylene group or a C—C100 fluorine-containing alkylene group and having an ether bond; and A is —COOM, —SO.sub.3M, or —OSO.sub.3M, wherein M is —H, a metal atom, —NR.sup.7.sub.4, imidazolium optionally having a substituent, pyridinium optionally having a substituent, or phosphonium optionally having a substituent, wherein R.sup.7 is H or an organic group, providing that at least one of X, Y, and Z contains a fluorine atom.

A push-in earplug is provided. The push-in earplug comprises an elongate core comprising a core material. The push-in earplug also comprises an outer layer comprising a foam material, the outer layer covering at least a portion of an outer surface of the elongate core. The push-in earplug also comprises a channel extending through the elongate core from a first end of the elongate core to the second end of the elongate core.

In various exemplary embodiments, the present disclosure provides a process for the conversion of certain polymers into diamond and diamond-like materials using laser pulse annealing. The process includes transforming the polymer to carbon, melting the carbon and quenching the carbon melt into to form Q-carbon, diamond, and/or graphene. The process can be applied to a polymer film such as a polytetrafluoroethylene (PTFE) tape. An object can be coated with the polymer film which can then be converted to Q-carbon, diamond, and/or graphene using laser pulse annealing. A process is also provided for making a three-dimensional object using a combination of, for example, 3D printing the polymer and converting each layer of polymer into Q-carbon, diamond and/or graphene.

A method for manufacturing a fired body of a fluororesin includes a mixing step of mixing a fluororesin pulverized after firing and an unfired fluororesin powder aggregated after emulsion polymerization at a rate based on predetermined strength to produce a component to be fired, and a firing step of firing the component to be fired produced.

A plastic preform apparatus is disclosed that is suitable for forming a bottle. The plastic preform apparatus features a neck portion adapted to engage a closure and includes a support ring at its lowermost point. The neck portion features a first wall thickness, and an elongated body portion including a cylindrical wall portion and an end cap. An upper segment of the body portion adjacent to the support ring features a second wall thickness substantially similar to the first wall thickness and less than a third wall thickness in a lower segment of the body portion.