Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
  • H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
  • H01B1/122—Ionic conductors
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/51—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof
  • D06M11/53—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof with hydrogen sulfide or its salts; with polysulfides
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
  • D06M2101/16—Synthetic fibres, other than mineral fibres
  • D06M2101/18—Synthetic fibres consisting of macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M2101/26—Polymers or copolymers of unsaturated carboxylic acids or derivatives thereof
  • D06M2101/28—Acrylonitrile; Methacrylonitrile

Definitions

• This invention relates to electrically conducting acrylic and modacrylic fibres and to methods of making them.
• One method for imparting electrical conductivity to polymeric fibres involves plating a metal onto the surface of the fibre.
• this method requires etching of the surface of the fibre prior to plating so as to obtain satisfactory adhesion, and then involves sensitising and activating the fibre prior to plating.
• the resulting electrically conducting fibre differs greatly from the starting fibre in softness, flexibility and smoothness.
• U.S. Patents 3,014,818 and 4,122,143 disclose the production of electrically conductive fibres by reducing a copper compound to metallic copper.
• an electrically conductive fibrous material is produced by soaking the fibres, such as cotton or acrylic fibres, in a bath comprising a reducible salt of nickel, cobalt, copper or iron; the fibre is then subjected to a reducing treatment to obtain free metal particles which are dispersed through the interior of the fibre.
• Sodium borohydride and hydroxylamine are disclosed as satisfactory reducing agents.
• cured products are obtained by reducing copper simultaneously with the curing of a resin; the method does not give electrical conductivity to an already existing fibre.
• the electrically conductive fibres of the present invention comprise acrylic or modacrylic fibres, which have been impregnated with a copper sulfide such as cupric or cuprous sulfide or digenite.
• Acrylic fibres are made from a synthetic linear polymer that consists of not less than 85% (by mass) of acrylonitrile units ( ) or acrylonitrile copolymers; modacrylic fibres contain not less than 35% of said units or copolymers.
• the term "fibre” or "acrylic fibre” is used hereinafter to refer to acrylic and modacrylic fibres.
• the preferred amount of monovalent copper ions adsorbed by the fibre is from 1 to 30% by weight (expressed in terms of the weight of metallic copper) based upon the initial weight of the fibre.
• an acrylic fibre or modacrylic fibre is first heat-treated in a bath containing monovalent copper ions and a reducing agent so that the fibre adsorbs the monovalent copper ions; the fibre is then heat-treated with a sulfur-containing compound to convert the adsorbed monovalent copper ions into a copper sulfide. This is a two-step process.
• the electrically conductive fibres of the invention have superior electrical conductivity and washability and can be dyed by cationic dyes.
• the fibres are heat-treated in a bath containing a compound providing monovalent copper ion and a reducing agent, so that monovalent copper ions are adsorbed by the fibres.
• the bath can optionally contain, for adjusting the pH of the bath to preferably 1.5 to 2.0, an acid or an acid salt such as sulfuric acid, hydrochloric acid or a salt thereof.
• Suitable copper compounds which provide monovalent copper ions for adsorption on the fibres are cupric salts, such as cupric sulfate, chloride, nitrate or acetate and chelate compounds of copper.
• Suitable reducing agents for inclusion in the bath are metallic copper, hydroxylamine, ferrous sulfate, ammonium vanadate, sodium hyphophosphite, glucose and furfural.
• the bath temperature is preferably in the range from 90°C to 110°C so as to efficiently adsorb the monovalent copper ions and to maintain the strength of the fibres. At temperatures below 90°C, it takes many hours to complete adsorption. At temperatures over 110°C, the strength of the fibres drops.
• the acrylic fibres having adsorbed monovalent copper ions become yellowish but do not possess any electrical conductivity.
• Electrical conductivity is imparted to the fibres in the second stage, wherein the fibres having adsorbed monovalent copper ions are preferably first thoroughly scoured or washed with water and the washed fibres are heat-treated in a liquid or gas which comprises a sulfur-containing compound which is capable of reacting with the adsorbed monovalent copper ions to produce a copper sulfide.
• the copper sulfide is adsorbed into the fibres, thereby imparting excellent electrical conductivity properties to the fibres.
• the weight percentage of the copper sulfide in the electrically conducting fibre expressed in terms of the weight of metallic copper is preferably also 1% to 30% based upon the initial weight of the fibre.
• Suitable sulfur-containing compounds for converting the monovalent copper ions into adsorbed copper sulfide are sodium sulfide, sulfur dioxide, sodium hydrogen sulfite, sodium pyrosulfite, sulfurous acid, dithionous acid, sodium dithionite, sodium thiosulfate, thiourea dioxide, hydrogen sulfide, sodium formaldehyde sulphoxylate and zinc formaldehyde sulphoxylate and mixtures thereof.
• the liquid which contains the sulfur-containing compounds is generally water, and for adjusting the pH values to preferably 5.5 to 6 can include an acid or an acid salt such as sulfuric acid, sodium acetate or hydrochloric acid.
• the heat-treatment temperature in the second state of this process of the present invention is preferably more than 50°C. Heat-treatment temperatures below 50°C do result in the production of a copper sulfide and impart electrical conductivity to the fibres, but many hours are needed to accomplish this at these low temperatures.
• the heat-treating in the second stage of the process of the present invention is at a temperature from 50°C to 105°C for about 1 hour and can be carried out in a gaseous sulfur-containing compound, such as sulfur dioxide.
• an acrylic or modacrylic fibre is heat-treated in a bath containing (i) divalent copper ions, (ii) a reducing agent capable of reducing said copper ions to monovalent ions, and (iii) a compound having the ability to release sulfur atoms and/or sulfur ions.
• This one-step process is simple to perform.
• cupric compounds such as cupric sulfate, chloride, nitrate or acetate or a chelate of copper are used.
• the reducing agent (ii) can be metallic copper, ferrous sulfate, ammonium vanadate, sodium hypophosphite, hydroxylamine or its sulfate, furfural or glucose.
• the sulfur-releasing compound can be any of the sulfur containing compounds listed above for the first process; the sulphoxylates can be used in the form of Rongalite C (NaHS0 2 .CH 2 0.2H 2 0) or Rongalite Z (ZnS0 2 .CH 2 0.H 2 0); sulfur dioxide or hydrogen sulfide can be used by being bubbled into the bath.
• acid or salt may be added, e.g. inorganic acid such as sulfuric or hydrochloric acid, organic acid such as citric acid or acetic acid or a combination of acid and salt such as citric acid and disodium hydrogen phosphate.
• the treatment termperature used in this one-step method is normally 50°C to 120°C; a temperature higher than 120°C is liable to reduce the fibre strength, although the reaction will be quicker.
• An electrically conducting fibre prepared by either process is washed thoroughly, e.g. with water, and then dried.
• Electrically conducting fibres obtained by the processes of the present invention were analyzed by X-ray diffraction techniques for the determination of the crystal structure of the adsorbed copper sulfide. It was thereby ascertained from the diffraction lines that the copper sulfide was adsorbed within the fibres in the form of digenite (empirical formula: CU9S5), cuprous sulfide or cupric sulfide.
• the copper compound and/or reducing agent used can be a single compound or a suitable mixture of compounds.
• Adsorption of the copper sulfide within the whole fibre results in a fibre which possesses excellent electrical conductivity and washability, and the touch and physical properties of the staring fibre is substantially preserved.
• the electrically conducting fibres of the present invention can be dyed, e.g. with cationic dyes. (Electrically conducting fibres produced by the metal plating method cannot be dyed.)
• the electrically conducting fibres of the present invention are dyed in an aqueous solution containing cationic dye at a temperature of about 100°C for about 30 minutes to 1 hour.
• An electrically conducting fibre of the present invention can be used for many purposes. It can be used alone or in combination with other fibres to produce woven or knitted fibrics for electric blankets, electrically heated clothing and the like. Excellent control over the electrical properties of knitted or woven goods is obtained by combining in one textile the electrically conductive fibres of the present invention with other non-conductive fibres. For example, a small amount of the electrically conductive fibres of the present invention can be mingled into knitted or woven goods in the form of filament fibres. Also, spun yarns can be produced from mixtures of the electrically conductive fibres of the present invention with other natural or synthetic fibres which are both in the form of staple fibres.
• the invention is illustrated but not limited by the following examples in which all percentages and ratios are by weight.
• the No. 31 mesh has 12 openings per square of side 1 inch (2.54 cm) long.
• the washing test involves washing the sample in a rotating drum in soapy water for 30 minutes at 50°C.
• the washed fibres were again heat-treated in an aqueous solution containing 10 grams of sodium formaldehyde sulphoxylate (Rongalite C, NaHS02.CH20.2H20) and 1 millilitre of sulfuric acid in relation to 1 litre of water, at a temperature of 80°C for 60 minutes.
• the electrically conducting fibre was dried after being washed in water for a second time. It had an olive-grey colour and contained 12.3% of copper sulfide in relation to the weight of the starting fibre. Its electrical resistivity was 0.085 ohm.centimetre.
• This electrically conducting fibre was treated in an aqueous solution containing 2% of Sumiacryl Brilliant Red N-4G (cationic dye, made by Sumitomo Chemical Industry Co., Ltd., Japan) in relation to the fibre weight at a temperature of 100°C for 30 minutes. It was excellently dyed a dark-red colour without deterioration of its conductivity.
• Sumiacryl Brilliant Red N-4G cationic dye, made by Sumitomo Chemical Industry Co., Ltd., Japan
• Example 1 was repeated except that Rongalite Z (ZnS0 2 .CH 2 0.H 2 0) was used in place of Rongalite C. There was likewise obtained an electrically conducting fibre of the same nature as the fibre obtained in Example 1.
• the ratio of the fibres to the water containing the chemicals was 1:15.
• the heat-treatment was at a temperature of 100°C for 90 minutes. The fibres were then thoroughly washed in water.
• the washed fibres were again heat-treated in an aqueous solution containing 10 grams of dithionous acid and 2 grams of sodium acetate per litre of water, at a temperature of 90°C for 60 minutes.
• the electrically conducting fibre obtained after being thoroughly washed in water and dried had an olive-grey colour and contained 10.8% of copper sulfide in relation to the weight of the starting fibre. Its electrical resistivity was 0.86 ohm-centimetre.
• this electrically conducting fibre was subjected ten times to the repeated washing test as in Example 1, deterioration of its conductivity was scarcely perceived. Further, this electrically conducting fibre was treated in an aqueous solution containing 2% of Diacryl Brilliant Blue H 2 R-N (cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan) in relation to the fibre weight at a temperature of 100°C for 60 minutes. The electrically conducting fibre was excellently dyed a dark-blue colour.
• Diacryl Brilliant Blue H 2 R-N cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan
• Example 3 The procedure of Example 3 was repeated except that instead of dithionous acid, either sodium dithionite, sodium thiosulfate, sodium hydrogen sulfite or sodium pyrosulfite was used. In each case, there was obtained an electrically conducting fibre of the same nature as the fibre obtained in Example 3.
• the washed fibres were again heat-treated in an aqueous solution containg 15 grams of sodium sulfide and 4 millilitres of sulfuric acid per litre of water, at a temperature of 90°C for 60 minutes.
• the electrically conducting fibre obtained after being thoroughly washed in water and dried had an olive-grey color and contained 15.1% by weight copper sulfide in relation to the weight of the starting fibre. Its electrical resistivity was 0.060 ohm.centimetre.
• this electrically conducting fibre was treated in an aqueous solution containing 4% of Diacryl Navy Blue RL-N (cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan) in relation to the fibre weight, at a temperature of 100°C for 60 minutes. An electrically conducting fibre dyed well in a dark-blue colour was obtained.
• Diacryl Navy Blue RL-N cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan
• the electrically conducting fibre was tested for washability and dyeability by cationic dyestuffs. The results were as good as in the case of Examples 1 to 8.
• Example 9 was repeated except that hydrogen sulfide was used instead of sulfur dioxide.
• An electrically conducting fibre of the same nature as the fibre obtained in Example 9 was obtained.
• the conductive fibre thus obtained has an olive green color, a copper sulfide content of 14.2% and an electrical resistivity of 0.036 ohm.centimetre. X-ray diffraction analysis showed it to contain cupric or cuprous sulfide or digenite. After the repeated washing test ten time as in Example 1, its resistivity had increased only slightly to 0.043 ohm.cm.
• the conductive fibre obtained was olive green, contained 13.8 % copper sulfide, had a resistivity of 0.058 ohm.cm, and showed digenite diffraction lines.
• the electrically conducting fibre was treated in an aqueous solution of Diacryl Navy Blue RL-N (cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan), and was dyed brilliantly navy blue without lowering the electric conductivity.
• Diacryl Navy Blue RL-N cationic dye, made by Mitsubishi Chemical Industry Co., Ltd., Japan
• a modacrylic fibre as used in Example 3 was treated as in Example 11 but in a bath containing 20 % of cupric sulfate, 80 % of copper net (No. 31, of a 12 mesh), 10 % of sodium thiosulfate and 5 % of sulfuric acid for 60 minutes at 100°C (reached after 45 minutes).
• the conductive fibre obtained was olive green, contained 9.2 % copper sulfide, had a resistivity of 1.3 ohm.cm and showed digenite diffraction lines.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

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Cited By (17)

Citations (3)

• 1981
  • 1981-03-03 EP EP19810300881 patent/EP0035406B1/fr not_active Expired
  • 1981-03-03 DE DE8181300881T patent/DE3165320D1/de not_active Expired

Patent Citations (3)

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