Patent GB-875664-A (GB)
Title: Improvements in or relating to modified natural polymers
IPC: D06M14/18
Filed: 1957-10-03
Abstract: Natural polymers or regenerated or modified natural polymers are contacted with one or more polymerizable monomers containing reactive non-aromatic carbon-to-carbon unsaturation and acid or acid salt groups (or functional groups which are subsequently converted to acid or acid salt groups) during or after irradiation with particulate or electromagnetic high energy ionizing radiation.  Examples of such monomers are carboxylic acids, such as acrylic, methacrylic, maleic, crotonic, itaconic, furoic, propiolic, fumaric, and dichloromaleic acids, preferably having up to 5 carbon atoms though acids having up to 20 carbon atoms may be used; salts thereof, e.g. calcium, sodium, potassium, and ammonium or amine salts; and derivatives thereof, e.g. acid chlorides, anhydrides, half acid esters or amides, esters, nitriles, aldehydes, or ketones; sulphonic acids (styrene or ethylene sulphonic acids); unsaturated alkyl or aralkyl acid phosphates, phosphites, phosphonates, and phosphinates; acid alkyl sulphates and carbonates.  In a modification of the process, acidic chain transfer agents, e.g. thioglycollic acid, chloropropionic acid, and chloroethanesulphonic acid, may be used in place of the monomer.  A mixture of monomers may be employed or a second monomer may be applied and grafted subsequently to the first.  The polymer may be in the form of fibres, filaments, films, or pellicles, woven, knitted, or felted fabric, bristle, or artificial straw.  Where the article is thick, a surface treatment only is effected.  Polymers referred to are of the protein, cellulose, and isoprene types, cotton, flax, jute, silk, wool, fur, hair, rubber, wood, regenerated cellulose, cellulose acetate, casein, alginate, and zein derivatives being specifically mentioned.  The compound may be applied to the polymer by melt coating or padding on as a dispersion, solution, pure liquid, or emulsion; an article may be sprayed or dipped in a liquid; the monomer may be added as a vapour; or the monomer may be added to a melt or solution of the polymer before shaping, e.g. by spinning. Radiations employed include electrons, nuclear particles such as protons, neutrons, a -particles, b -particles, and deuterons, and X-rays produced by irradiating a metal, e.g. gold or tungsten, with electrons.  In the example, accelerated electrons are employed.  The preferred dose is at least 0,01 Mrep: it should be sufficient to graft at least 200 equivalents of titratable acid groups per 106 grams of polymer.  Where the irradiation is conducted before contacting with the monomer it is preferred to maintain the temperature during irradiation and before contacting at below room temperature, preferably below 0 DEG C., and to employ an inert gas atmosphere or vacuum during irradiation; where irradiation takes place in the presence of monomer, room temperature or higher temperatures, e.g. 100 DEG -160 DEG C. may be used. With such temperatures it is desirable to exclude oxygen. Subsequently to formation of the graft polymer, the free acid may be converted to the salt form, e.g. by contacting with a solution of a salt of the desired cation, e.g. sodium, calcium, lithium, ammonium, or amine, with a weak acid: when using a solution containing more than one ion, one ion may be picked up selectively and a sequestrant for this ion may permit a second ion to form the salt; if desired after incorporating one ion (sodium) in the graft polymer, a second (calcium) may be attached near the surface.  In the example, fabric samples are soaked in aqueous acrylic acid, wrapped in aluminium foil, irradiated, and treated.  The product may have greater resistance to hole melting, greater receptiveness to basic dyes, increased resistance to flash heat, and higher zero strength temperature.  Some products having salt groups when subjected to heating show shrinkage and by using yarns of modified and unmodified polymer in the same fabric, by applying the unsaturated acid or metal ions in a pattern, or by shielding parts of the structure during grafting, textured effects may be achieved.  Part or the whole of the subject-matter of Specifications 758,735, 834,557, 845,897 and 845,898 is disclaimed.  Specification 801,531 also is referred to. Reference has been directed by the Comptroller to Specifications 801,528 and 809,838.ALSO:Natural polymers or regenerated or modified natural polymers, e.g. proteins such as silk, wool, fur or hair, or casein or zein derivatives are contacted with one or more acidic chain transfer agents e.g. thioglycollic acid, chloropropionic acid or chloroethansulphonic acid, during or after irradiation with particulate or electromagnetic high energy ionising radiation. Part or the whole of the subject-matter of Specifications 834,557, 845,898, 845,897 and 758,735 is disclaimed.  Specification 801,531 also is referred to.  Reference has been directed by the Comptroller to Specifications 801,528 and 809,838.ALSO:The properties of natural polymers or regenerated or modified natural polymers and of yarns and textiles produced therefrom are modified by contacting said polymers with one or more polymerizable monomers containing reactive non-aromatic carbon-to-carbon unsaturation and acid or acid salt groups (or functional groups which subsequently are converted to acid or acid salt groups) during or after irradiation with high energy particulate or electromagnetic ionizing radiation (see Group IV(a)): in a modification the monomer is replaced by an acidic chain transfer agent.  The polymer may be in the form of fibres, filaments, films or pellicles, woven or knitted fabric, bristle or artificial straw; polymers referred to are of protein, cellulose and isoprene types, cotton, flax, jute, silk, wool, hair, rubber, regenerated cellulose, cellulose acetate, casein, alginate and zein derivatives being referred to.  The products may have a greater resistance to hole melting, greater receptiveness to basic dyes, increased resistance to flash heat and higher zero strength temperature.  Some products having salt groups when subjected to heating show shrinkage and by using yarns of modified and unmodified polymer in the same fabric, by applying the unsaturated acid or metal ions in a pattern or by shielding part of a structure during grafting, textured effects may be achieved. Part or the whole of the subject-matter of Specifications 758,735, 834,557, 845,897 and 845,898 is disclaimed. Specification 801,531 also is referred to.  Reference has been directed by the Comptroller to Specifications 801,528 and 809,838.