发明名称 |
Porous polytetrafluoroethylene Membrane and air filter medium |
摘要 |
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 DEG 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. |
申请公布号 |
EP1291060(A3) |
申请公布日期 |
2003.07.09 |
申请号 |
EP20020024587 |
申请日期 |
1997.05.16 |
申请人 |
NITTO DENKO CORPORATION |
发明人 |
ISHINO, TOSHIAKI;NABATA, NORIKANE;MAEOKA, TAKUYA |
分类号 |
C08J9/00;B01D39/08;B01D39/16;B01D67/00;B01D69/10;B01D69/12;B01D71/36;B29C55/00;B29K27/18;B29K105/04;B32B27/12;C08J9/28;D04H13/00 |
主分类号 |
C08J9/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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