Patent ID: 9132616
Filing Date: 2015-09-15
Classification: B01D,B32B,Y10T

Abstract:
1. A process for producing a composite membrane material, the process comprising: processing a polymeric material to produce at least first and second porous membranes formed of the polymeric material, each of the first and second porous membranes comprising pores; providing at least a third porous membrane formed of the polymeric material, the third porous membrane having pores that have an average pore size greater than average pore sizes of the pores of each of the first and second porous membranes, and wherein the first and second porous membranes are more amorphous and less crystalline than the third porous membrane; without applying a separate adhesive material therebetween, laminating the first, second and third porous membranes together by applying heat and pressure to the first, second and third porous membranes to cause incipient melting of at least the first and second porous membranes, wherein during the laminating step the first and second porous membranes start to melt prior to any melting of the third porous membrane; and then cooling the first, second and third porous membranes to cause the first and second porous membranes to bond to each other by resolidified portions thereof that extend through the third porous membrane, the first, second and third porous membranes being laminated together to form a composite membrane material wherein the third porous membrane is between the first and second porous membranes, the composite membrane material having an effective pore size of less than the average pores sizes of each of the first, second and third porous membranes.