Semipermeable membrane

Abstract

Abstract Sheet material, suitable for use as a semipermeable membrane, comprises an organic hydrophilic pellicle, e.g. a foil, film, sheet, bag or tubing, containing a deposit therein of a water-insoluble synthetic resin and is made by impregnating the pellicle, preferably in the gelled state, with a solution or dispersion of a polymerized or partially condensed synthetic resin in a volatile solvent or a monomer or mixture of monomers, removing excess impregnant from the surface of the pellicle and hardening the resin or polymerizing the monomer at room or elevated temperature, e.g. in the presence of polymerization catalysts such as hydrogen peroxide, benzoyl peroxide, acids or alkalis. Specified polymerized resins are polyvinyl chloride, acetate, or butyral, polyvinylidene chloride, polystyrene, coumaroneindene, polymethylmethacrylate, copolymers of vinyl chloride and acetate, or vinylidene chloride and mixtures. The partially condensed resins may be a phenol-, urea-, melamine-, or sulphonamide-aldehyde, phenolfurfural, an alkyd, or a urea-formaldehyde alcohol ether resin. Specified monomers are allyl chloride or bromide, allyl alcohol, furfural, furfuryl alcohol, indene, heptylenes, octylenes, coumarone, methyl, ethyl, or butyl acrylate, methyl, ethyl, n-butyl, isobutyl, methoxyethyl or cyclohexyl methacrylates, vinyl acetate, vinyl ethyl ether and mixtures. The solvent may be water, acetic acid, methyl or ethyl alcohol, glycerine, ethylene glycol, di- or tri-ethyl glycol, ethanolamine, triethanolamine, diethanolamine and mixtures. The solvent preferably has a swelling action on the pellicle. The solution or dispersion may contain pigments, dyestuffs, fireproofing agents, or plasticizers, e.g. dibutyl phthalate, soft alkyd resins or waxes. Prior to impregnation the pellicle may be treated with swelling agents, e.g. zinc chloride, sodium hydroxide or calcium thiocyanate. The pellicle may be cleaned with sodium perborate solution prior to use. The pellicle may be made from cellulose hydrate, regenerated cellulose, cellulose ethers or esters, denitrated nitrocellulose, gelatin, casein, deacetylated chitin, water-swelling polymers of acrylic acid or methyl methacrylate, polyvinyl alcohol, urea or phenol-formaldehyde resins in the "A" stage, parchment paper, leather scrap or fibre-bonded felted papers made according to Specifications 547,288 and 572,962, [both in Group VIII]. Two or more pellicles may be laminated to each other or to untreated films or sheets.ALSO:In the separation of materials of different molecular weight and constitution, a semi-permeable membrane is used consisting of an organic hydrophilic pellicle, e.g. a foil, film, sheet, bag or tube and containing a deposit therein of a water-insoluble synthetic resin. Two or more pellicles may be laminated to each other or to untreated pellicles. The resin may be polyvinyl chloride, acetate, or butyral, polyallyl chloride, bromide or alcohol, polyacrylates or polymethacrylates, polyvinyl ethyl ether, polystyrene, polyvinylidene chloride, copolymers of vinyl chloride with vinyl acetate or vinylidene chloride, coumarone-indene, phenol-, urea-, melamine- or sulphonamide-aldehyde resins, phenol-furfural or an alkyd, or mixtures. The pellicle may be made from cellulose hydrate, regenerated cellulose, cellulose ethers or esters, denitrated nitrocellulose, gelatine, casein, deacetylated chitin, water-swelling polymers of acrylic acid or methyl methacrylate, polyvinyl alcohol, urea or phenol-formaldehyde resins in the "A" stage, parchment paper, leather scrap or fibre-bonded felted papers made in accordance with Specifications 547,288 and 572,962, [both in Group VIII]. The membranes may be used for separating glycerine from beer slops, and salts, sugars and impurities from molasses, milk, blood, latex, dextrins, vitamins, and hormones.

Inventors

• 👤 Ralph T K Cornwell
• 👤 Zender Justin

Bibliographic Details