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AssigneePall Corporation
InventorsPeter John Degen, Ioannis P. Sipsas, Gregory C. Rapisarda, Joseph Gregg
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The present invention provides an isotropic, skinless, porous, polyvinylidene fluoride membrane having a K.sub.UF of at least about 15 psi (103 kPa), and preferably below about 50 psi (345 kPa), when tested using liquid pairs having an interfacial tension of about 4 dynes/cm (4 mN/m). The present inventive membrane preferably has a titer reduction of at least about 10.sup.8 against T.sub.1 bacteriophage, more preferably also against PR772 coliphage, and even more preferably also against PP7 bacteriophage. The present inventive membrane can have a thickness of about 20 mil (500 .mu.m) or less and even as low as about 5 mil (125 .mu.m) or less. The present invention also provides a method of preparing such a membrane by providing a casting solution comprising polyvinylidene fluoride and a solvent therefor, heating the casting solution to a uniform temperature of about 57.degree. C. to about 60.degree. C., spreading the casting solution onto a substrate to form a film, quenching the film in a quench bath so as to form a porous membrane, and washing and drying the porous membrane.
An isotropic, skinless, porous polyvinylidene fluoride membrane comprising a surface coating of a polymer having the characteristics of rendering said membrane hydrophilic and less susceptible to the adsorption of proteins, wherein said membrane has the characteristic of achieving a titer reduction of at least about 10.sup.8 against T.sub.1 bacteriophage.
A method of preparing an isotropic, skinless, porous polyvinylidene fluoride membrane having (a) a K.sub.UF of at least about 15 psi when tested using liquid pairs having an interfacial tension of about 4 dynes/cm or (b) the characteristic of achieving a titer reduction of at least about 10.sup.8 against T.sub.1 bacteriophage, which method comprises providing a casting solution comprising polyvinylidene fluoride and a solvent therefor, heating said casting solution to a uniform temperature of about 57.degree. C. to about 60.degree. C., spreading said casting solution onto a substrate to form a film, quenching said film in a quench bath so as to form a porous membrane, and washing and drying said porous membrane.
Dependencies are inferred from the claim text.