Composite membrane support and composite membrane using the same

摘要

An object of the present invention is to provide a composite membrane support composed of a dry process thermoplastic resin filaments nonwoven fabric having a significantly high uniformity to enable formation of a porous layer free from strike-through or a defect such as pinhole at the film formation, producing no skin layer defect at the formation of a skin layer, and being excellent in the mechanical strength and dimensional stability at high temperatures, and a high-performance composite membrane and a composite membrane element each using the composite membrane support. The composite membrane support of the present invention is a laminate dry process thermoplastic resin filaments nonwoven fabric comprising three or more layers containing at least a meltblown fiber layer as an interlayer and spunbond fiber layers on both sides of the interlayer, wherein the average value of air flow resistance is from 2.0 to 30.0 kPa·s/m and the ratio between the average value and the standard deviation of air flow resistance is 0.6 or less.

主权项

1. A composite membrane support, which is a laminate dry process thermoplastic resin filaments nonwoven fabric comprising three or more layers containing at least a meltblown fiber layer as an interlayer and spunbond fiber layers on both sides of said interlayer, wherein the average value of air flow resistance of said composite membrane support is from 2.0 to 30.0 kPa·s/m, the ratio between the average value and the standard deviation of air flow resistance is 0.6 or less, and the thermal-time constant-load elongation ratio in the Machine direction of said composite membrane support is 1.1% or less, wherein each of the meltblown fiber and the spunbond fiber is composed of a single-component fiber, and wherein said laminate dry process thermoplastic resin filaments nonwoven fabric is prepared by a process where said there or more layers are calendared with a non-heated elastic roll having a specific hardness and a heated metal roll in two stages, one stage for one surface and another stage for another surface, and immediately after calendaring of one surface, the web is rapidly cooled.