Patent GB-834557-A (GB)
Title: Process for modifying fibres or films from natural or regenerated natural polymers
IPC: B29C71/04
Filed: 1956-04-06
Abstract: The properties of natural, modified or regenerated natural polymers are changed by subjecting a polymer to ionizing radiation while it is in intimate contact with at least one organic compound, which chemically bonds (as such or in the form of a polymeric structure) with the natural polymer.  The modifier which may be dispersed, diffused or coated upon the polymer is preferably kept in an inert atmosphere or is enclosed by a polyethylene film or aluminium foil or other material which is impervious to air and water while it is being irradiated. Additionally it may be in contact with a compound having protective or antioxidant effects with respect to the polymer, the modifier or both, and during the irradiation the temperature is preferably kept between 0 DEG  and 75 DEG  C., if necessary by cooling. The process is preferably carried out in the presence of calcium tungstate, zinc sulphate, metallic lead or other radiation transfer agent capable of absorbing radiation and re-emitting it in a lower form of energy.  Examples of radiation dosages are given. Organic modifiers for use in the invention may be found among all classes of organic compounds, and may contain, besides carbon, one or more of the elements hydrogen, halogen, nitrogen, oxygen, or sulphur. Those organic compounds, the bonds of which are easily broken, as for instance chain transfer agents, are particularly preferred.  They may be of low molecular weight or of high molecular weight, especially of polymeric structure.  Thus there may be used alcohols, such as methanol, ethanol, laurol; glycols, such as glycerol, pentaerythritol, sorbitol, mannitol and partial esters of these polyols; ethers, such as dimethyl, diethyl and ethylmethyl ethers, glycol ethers; oxyalkylated ethers of partial esters of the polyols, such as the polyoxyethylene derivatives of fatty acid partial esters of sorbitol; polyethers, such as polyoxyethylene, mercaptans, disulphides and thioethers analogous to the above; amines, such as methylamine, ethylamine, hexamethylene diamine and dodecylamine; amides of these amines formed with acids, such as formic acid, adipic acid, suberic acid and stearic acid; halides, such as chloromethane, chloroform, carbon tetrachloride, chloroethane, and dichlorodifluoromethane, chloroethylene and dodecafluoroheptyl alcohol.  The modifier may be an unsaturated compound, particularly one which may be employed to form addition polymers by vinyl polymerization, e.g. styrene, the acrylic acid esters, vinyl chloride, vinylidene chloride, vinyl acetate, the vinyl ketones, the vinyl ethers, such as divinyl ether, acrylonitrile, methacrylonitrile, methoxydedocamethyleneoxy methacrylate, 1,3-butadiene, isoprene, chlorprene, 2,3-dimethyl-1, 3-butadiene, ethylene, propylene, the acetylenes for instance phenylacetylene, the allyl esters, vinyl compounds (other than those already mentioned) containing halogen, sulphur, nitrogen or phosphorus, and the vinyl silanes. Polymers prepared from such of the above monomeric materials as are polymerisable are also suitable.  The modifiers may be incorporated with the polymer before shaping, or they may be applied to the shaped articles, e.g. as solutions or in suitable cases as pure compounds, for instance by spraying, calendering, immersion, padding, or exposure to vapour condensation.  In suitable cases a solution of the modifier may be applied to the surface of a shaped article and the solvent flashed off before the irradiation.  If desired, excess liquid may be removed before irradiation by squeezing.  Natural polymers treated in accordance with the invention are cellulose, protein or isoprene polymers obtained in nature, or a derivative or regeneration product of one of these.  Natural fibres include cotton, flax, jute, hemp, ramie, sisal, abaca, phormium, silk, wool, fur and hair.  A natural fibre- and film-forming material is rubber.  Fibres and films of regenerated cellulose, cellulose derivatives such as cellulose acetate, and films of film-forming natural fats and oils, such as tung oil, linseed and oiticica oil, may also be treated.  The expression "fibres and films" is intended to include all articles having at least one dimension very small, and thus having a large ratio of surface to volume, including continuous filaments, staple fibres, and yarns containing them, their films, and woven, knitted, felted or fused fabrics.  In a modification of the invention, the treatment may be applied to finely comminuted particles of a polymer which, like cellulose acetate for instance, can be obtained in this form, and the particles may be dissolved and formed into a shaped article, e.g. into fibres by dry or wet spinning.  The invention may also be used to improve the oil-resistance of rubber.  Those properties which are not primarily a function of surface characteristics (e.g. tenacity, elongation, modulus, and the like) in some cases may be more conveniently modified by incorporating modifiers in the polymeric matrix and then subjecting it to particle irradiation.  It may be desirable to incorporate one or more modifiers in the matrix and coat one or more modifiers on the surface of the article.  Examples of specific shaped articles which may be treated include woven or knitted fabrics, articles made from them for clothing or industrial use, reinforcement for composite structures (such as cords for mechanical rubber goods and fibre for laminates), artificial bristles or artificial straw. Specifications 758,735 and 798,340 are referred to.ALSO:The properties of proteins are changed by subjecting the protein to ionizing radiation while it is in intimate contact with at least one organic compound, which chemically bonds (as such or in the form of a polymeric structure) with the protein.  The modifier which may be dispersed, diffused or coated upon the protein is preferably kept in an inert atmosphere or is enclosed by a polyethylene film or aluminium foil or other material which is impervious to air and water while it is being irradiated. Additionally it may be in contact with a compound having protective or anti-oxidant effects with respect to the protein, the modifier or both, and during the irradiation the temperature is preferably kept between 0 DEG  and 75 DEG  C., if necessary by cooling. The process is preferably carried out in the presence of calcium tungstate, zinc sulphate, metallic lead or other radiation transfer agent capable of absorbing radiation and re-admitting it in a lower form of energy.  Examples of radiation dosages are given.  Organic modifiers for use in the invention may be found among all classes of organic compounds, and may contain, besides carbon, one or more of the elements hydrogen, halogen, nitrogen, oxygen, or sulphur.  Those organic compounds, the bonds of which are easily broken, as for instance chain transfer agents, are p particularly preferred.  They may be of low molecular weight or of high molecular weight or of high molecular weight, especially of polymeric structure.  Thus there may be used alcohols, such as methanol, ethanol, laurol; glycols, such as glycerol, pentaerythritol, sorbitol, mannitol and partial esters of these polyols; ethers, such as dimethyl, diethyl and ethylmethyl ethers, glycol ethers; oxyalkylated ethers of partial esters of the polyols, such as the polyoxyethylene derivatives of fatty acid partial esters of sorbitol; polyethers, such as polyoxyethylene, mercaptans, disulphides and thioethers analogous to the above; amines, such as methylamine, ethylamine, hexamethylene diamine and dodecylamine; amides of these amines formed with acids, such as formic acid, adipic acid, suberic acid and stearic acid; halides, such as chloromethane, chloroform, carbon tetrachloride, chloroethane, and dichlorodifluoromethane, chloroethylene and dodecafluoroheptyl alcohol.  The modifier may be an unsaturated compound, particularly one which may be employed to form addition polymers by vinyl polymerization, e.g. styrene, the acrylic acid esters, vinyl chloride, vinylidene chloride, vinyl acetate, the vinyl ketones, the vinyl ethers, such as divinyl ether, acrylonitrile, methacrylonitrile, methoxydedocamethyleneoxy methacrylate, 1,3-butadiene, isoprene, chlorprene, 2,3-dimethyl-1, 3-butadiene, ethylene, propylene, the acetylenes for instance phenylacetylene, the allyl esters, vinyl compounds (other than those already mentioned) containing halogen, sulphur, nitrogen or phosphorus, and the vinyl silenes.  Polymers prepared from such of the above monomeric materials as are polymerizable are also suitable.  The modifiers may be incorporated with the protein before shaping, e.g. into fibres or films or they may be applied to the shaped articles, e.g. as solutions or in suitable cases as pure compounds, for instance by spraying, calendering, immersion, padding, or exposure to vapour condensation.  In suitable cases a solution of the modifier may be applied to the surface of a shaped article and the solvent flashed off before the irradiation.  If desired excess liquid may be removed before irradiation by squeezing.  Before being given the treatment of this invention the fibres or films may be oriented by drawing.  Also they may in suitable cases contain pigments, anti-oxidants, polymerization catalysts, or other additives.  After the irradiation they may be after-treated.  For exampe they may be washed in a detergent liquid to remove any decomposition products that may have formed on the surface, or they may for instance be dyed, bleached, drawn, chemically modified, or given a coating, e.g. of a lubricant or size.  Specifications 758,735 and 798,340 are referred to.ALSO:The properties of natural, modified or regenerated natural polymers are changed by subjecting a polymer to ionizing radiation while it is in intimate contact with at least one organic modifier which chemically bonds (as such or in the form of a polymeric