Nitto-denko Corporation

Nitto Denki Corporation

Norikane Nabata

Takuya Maeoka

Eizo Kawano

Toshiaki Ishino

Yozo Nagai

Hiroyuki Nishii

Hiroaki Mashiko

Polytetrafluoroethylene porous film is laminated with an ultra high molecular weight polyolefin porous film to realize excellent formability, dust collecting ability, and permeability that could not be attained by these porous films used alone. The laminate, which can be formed to prescribed shape if desired, is used to make a container for holding an adsorbent.

Laminate for container and container for adsorbent

The present invention provides a compact and inexpensive air-permeable cap and an outdoor lamp, automobile lamp and automobile electrical component including such an air-permeable cap. A novel air-permeable cap is provided including a closed-end cylindrical cover member, a substantially cylindrical body fitted in the closed-end cylindrical cover member, and an air passage formed between the inner wall of the closed-end cylindrical cover member and the outer wall of the substantially cylindrical body and between the bottom surface of the closed-end cylindrical cover member and the lower end of the substantially cylindrical body, wherein the mounting portion at which the air-permeable cap is mounted on the mounting opening of the housing is formed at the top of the substantially cylindrical body.

Air permeable cap and outdoor lamp, automobile lamp and electrical component comprising same

A filter medium for filters wherein the evolution of organic gases and dusting from a reinforcing member are depressed and thus the excellent characteristics inherent to a porous polytetrafluoroethylene membrane as a collection layer are fully achieved. The filter medium (1) for filters comprises a porous polytetrafluoroethylene membrane (2) and a porous ultrahigh-molecular weight polyolefin membrane (3) as a reinforcing member for the filter medium.

Filter medium for filters

A filter medium for air filters wherein the collection performance of polytetrafluoroethylene (PTFE) membranes is not damaged even after processing, for example, pleating and bonding to air-permeable supporting members. The filter medium containing a laminate (,) containing at least three layers of porous PTFE membranes wherein the pressure drop of a porous PTFE membrane (,) located as an outermost layer has a pressure drop of 1/2 times or less the pressure drop of porous PTFE membrane (,) located as at least one intermediate layer. Air-permeable supporting members (,) are bonded to both outermost layers of the laminate (,) to obtain a filter medium for air filters (,).

Filter medium for air filters

A filtering medium for air filters wherein its surface conditions have been improved, whereby the porous PTFE membrane is not damaged even after pleating, thus appropriately meeting needs for clean space in clean rooms. The filtering medium comprises a porous polytetrafluoroethylene membrane (2) and an air-permeable supporting member (1) which are laminated such that at least one of exposed surfaces comprises a surface of the air-permeable supporting member (1) having a maximum frictional resistance of 25 gf or less. This filtering medium can be obtained by, for example, press bonding the air-permeable supporting member (1) to the porous membrane (2) under heating and then pressing the surface of the air-permeable supporting member (1) to a silicone roll (4) for smoothing.

Filtering medium for air filters and process for producing the same

A fine powder of polytetrafluoroethylene is mixed with a liquid lubricant, and the mixture is molded into an unsintered sheet by at least one of an extrusion method and a rolling method. The liquid lubricant is removed from the sheet by at least one of a heating method and an extrusion method. This sheet-form molding is stretched in the machine direction to produce a sheet-form polytetrafluoroethylene molding which, upon analysis with a differential scanning calorimeter, gives a crystal fusion curve having an endothermic peak in the temperature range of 345.+-.5.degree. C. and which has a degree of crystallization of from 0.1 to 0.85 and a specific gravity of 1.4 or lower. The molding is then stretched in the transverse direction to produce a porous polytetrafluoroethylene (PTFE) membrane. The process is effective in producing, with good reproducibility, a useful porous PTFE membrane which has a high collection efficiency and a low pressure loss and is reduced in the leakage of coarse particles.

Porous polytetrafluoroethylene membrane, process for producing the same,

An air filter comprising a laminate of a non-woven fabric made up of polyolefin fibers or polyester fibers or a composite of the non-woven fabrics and a PTFE porous film, wherein the amount of the total gases generated from the air filter is 20 .mu.g/g by the analysis of gas chromatography. The amount of the gases generated from the air filter is greatly reduced by heat-treating the non-woven fabric at a temperature of from 80 to 130.degree. C. for from 5 minutes to 20 minutes before or after laminating with the PTFE porous film.

Production method for laminated air filter

A fine powder of polytetrafluoroethylene is mixed with a liquid lubricant, and the mixture is molded into an unsintered sheet by at least one of an extrusion method and a rolling method. The liquid lubricant is removed from the sheet by at least one of a heating method and an extrusion method. This sheet-form molding is stretched in the machine direction to produce a sheet-form polytetrafluoroethylene molding which, upon analysis with a differential scanning calorimeter, gives a crystal fusion curve having an endothermic peak in the temperature range of 345.+-.5 .degree. C. and which has a degree of crystallization of from 0.1 to 0.85 and a specific gravity of 1.4 or lower. The molding is then stretched in the transverse direction to produce a porous polytetrafluoroethylene (PTFE) membrane. The process is effective in producing, with good reproducibility, a useful porous PTFE membrane which has a high collection efficiency and a low pressure loss and is reduced in the leakage of coarse particles.

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Osaka, Japan

Norikane Nabata