Nonwoven fabric laminates suitable for use as semipermeable membrane
supports are produced by forming a spunbond nonwoven fabric first layer
of continuous thermoplastic polymer filaments; forming a wet-laid
nonwoven fabric second layer of discrete length thermoplastic polymer
fibers; and bonding the first and second layers in opposing face-to-face
relationship to form a composite support, where the first and second
layers define first and second outer surfaces of the composite support.
The resulting semipermeable membrane supports provide an advantageous
balance of properties, including smoothness, porosity, interlaminar
adhesion, and flux properties.