Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/34—Ignifugeants
• • 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
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/244—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing sulfur or phosphorus
• • 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
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/244—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing sulfur or phosphorus
  • D06M13/282—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing sulfur or phosphorus with compounds containing phosphorus
  • D06M13/285—Phosphines; Phosphine oxides; Phosphine sulfides; Phosphinic or phosphinous acids or derivatives thereof
• • 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
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
  • D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/39—Aldehyde resins; Ketone resins; Polyacetals
  • D06M15/423—Amino-aldehyde resins
  • D06M15/43—Amino-aldehyde resins modified by phosphorus compounds
  • D06M15/431—Amino-aldehyde resins modified by phosphorus compounds by phosphines or phosphine oxides; by oxides or salts of the phosphonium radical
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
  • D21H25/04—Physical treatment, e.g. heating, irradiating
  • D21H25/06—Physical treatment, e.g. heating, irradiating of impregnated or coated paper

Definitions

• This invention relates to a fabric treatment process, in particular one for rendering fabrics flame retardant with organo phosphorus compounds.
• THP compounds tetrakis (hydroxymethyl) phosphonium compounds
• precondensates thereof with urea has been described in USP2983623, 4068026, 4078101, 4145463 and 4494951.
• the treatment processes involved impregnation of the fabric with an aqueous solution of the chemicals, followed by drying, treatment with ammonia to cure the phosphorus compounds in order to insolubilize the phosphorus onto the fabric, finally with oxidation and washing to leave a treated fabric whose flame resistance is retained even after many washes in use.
• the cure efficiency (which is a measure of the effectiveness of the cure in insolubilizing the phosphorus on the fabric), is not always ideal and a percentage of the expensive phosphorus chemicals applied in the impregnation step is not cured. Thus it is washed off the fabric after the cure and wasted, particularly for cotton polyester fabrics and especially polyester cotton fabrics. In some cases, adequate flame retardant properties cannot be provided to the latter with THP compounds. Furthermore, while some techniques enable the necessary flame retardant properties to be provided to the fabric when first cured, those properties often diminish significantly on repeated washing.
• the present invention provides a process for the flame-retardant treatment of an organic fibrous substrate containing reactive groups, which process comprises impregnating said substrate with an aqueous solution of an organophosphorus compound, to provide an impregnated substrate which is dried and cured, by heating at a temperature of at least 100°C.
• the organic fibrous substrate is especially one comprising or consisting essentially of cellulosic fibres.
• the cellulosic fibres are preferably natural cotton, but may be ramie, flax, paper or cardboard or regenerated fibres (e.g. viscose or cuprammonium fibres) or partly etherified or esterified cellulose (e.g. cellulose acetate or propionate).
• the substrate may be substantially completely cellulosic eg 100% cotton or may contain both cellulosic and non cellulosic organic fibres, or just contain non cellulosic organic fibres eg 100% polyester fibres. Inorganic fibres such as glass fibres are usually absent.
• the non cellulosic fibres are preferably polyester or polyamide fibres but may also be acrylic.
• the polyamide may be an aliphatic one, such as copolymers of a polyamine (such as a diamine) preferably an alkylene diamine, eg of 4-12 carbon atoms and a poly carboxylic acid eg a dicarboxylic acid, of 4-14 carbon atoms such as an alkylene dicarboxylic acid (e.g. Nylon 66), or polylactams such as Nylon 6.
• the polyamide may be an aromatic one, such as aramids based on aromatic dicarboxylic acids and phenylene diamines.
• the acrylic polymer may be polyacrylonitrile homopolymer or copolymer with vinyl chloride, as in modacrylic fibres.
• the substrate can contain at least 20% of cellulosic fibres and up to 80% of coblendable fibres e.g. 10-80% especially 25-80% of coblendable fibres such as polyamides.
• the substrate comprises cellulosic fibres and polyester fibres.
• the substrate usually contains up to 80% (e.g up to 70%) polyester fibres and from 20% (e.g. from 30%) upwards of cellulosic fibres, e.g. 1-80% or 1-70%, such as 15-70% particularly 22-38% or 45-75% polyester fibres and 20-99% or 30-99% (such as 30-85%), particularly 62-78% or 25-55% cellulosic fibres.
• Substrates comprising at least 45% non cellulosic fibres are preferred as are ones comprising 30-78% cellulosic fibres and 22-70% polyester fibres, or 30-62% cellulosic fibres and 38-70% polyester fibres.
• the polyester is usually a condensation product containing structural units from an aliphatic alcohol, e.g. dihydric alcohol, especially ethylene glycol or butane diol (or mixtures thereof) and an aromatic dicarboxylic acid, e.g. terephthalic acid, or a mixture thereof with other dicarboxylic acids, such as isophthalic acid, or sebacic acid.
• the substrate fibres may be in the form of thread or non woven fabric, but are preferably as woven fabric.
• Mixtures of fibres e.g. of cellulosic and other fibres may be an intimate or non intimate mixture but the fibres are preferably in the form of blend of cellulosic fibres and the other fibres e.g. polyester fibres, as in cospun blends such as cotton/polyester or polyester/cotton staple fibre, but may be in the form of core spun yarn with a core of the other fibre e.g. polyester sheathed in cotton fibres.
• the warp and weft fibres are preferably the same, but may be different e.g. one may be from cotton fibres and the other from e.g.
• polyester/cotton fibres are polyester/cotton fibres.
• the term "blend” also includes unions and union/blends as well as core sheath fibres.
• the substrate is preferably a fabric with a weight of 0.05-1.0kg/m2, e.g. 0.150-0.40kg/m2, or 0.05-0.20kg/m2. Examples are polyester/cotton shirting or sheeting or curtain fabric.
• each hydroxyorgano group is preferably an alpha -hydroxyorgano group of 1-9 carbons.
• alpha -(hydroxyorgano) group is one of formula HOC-(R1R2), wherein each of R1 and R2 (these being the same or different) represents hydrogen or an alkyl group of 1 to 4 carbons, e.g. methyl, or ethyl.
• R1 is hydrogen
• R2 is methyl or especially hydrogen, as in tetrakis (hydroxymethyl) phosphonium (THP) compounds.
• the substrate is treated with an impregnation solution which is an aqueous solution of a THP salt mixed with a nitrogen compound condensable therewith to form a water soluble precondensate, or a solution of a precondensate of said salt and nitrogen compound, or a solution of THP salt, or water soluble self-condensate thereof, or at least partly neutralised THP salt, (e.g. THP hydroxide), with or without the nitrogen compound.
• an impregnation solution which is an aqueous solution of a THP salt mixed with a nitrogen compound condensable therewith to form a water soluble precondensate, or a solution of a precondensate of said salt and nitrogen compound, or a solution of THP salt, or water soluble self-condensate thereof, or at least partly neutralised THP salt, (e.g. THP hydroxide), with or without the nitrogen compound.
• the impregnation solution may alternatively comprise a solution of said precondensate and further nitrogen compound (eg urea), as in a solution with a molar ratio of total nitrogen compound (free and combined) to THP group (free and combined) of 0.8-2:1, eg 0.8-1.5:1.
• the nitrogen compound is preferably one with at least two NH groups (such as 2-4), but advantageously contains two NH or especially two NH2 groups.
• the nitrogen compound is usually bifunctional and may be an amine but is especially an amide.
• nitrogen compounds examples include biuret, guanidine, melamine and methylolated melamines, but urea is the preferred species for the purposes of this invention, especially in the absence of melamine or a methylolated melamine.
• the nitrogen compound is preferably urea whenever it is present in the precondensate.
• the solution contains a precondensate of THP salt, e.g. chloride or sulphate, and the nitrogen compound in a molar ratio of nitrogen compound to THP of 0.05-0.8:1, e.g. 0.05-0.6:1, or 0.22-0.8:1, such as 0.25-0.6:1, especially 0.4-0.6:1.
• the pH of said solution is usually 2-7.5, such as 4-6.5, e.g. 4-5.
• the atom ratio of total N atoms in the nitrogen compound or condensate to the total P atoms from THP salt or condensate in the impregnation solution is usually not greater than 4:1, eg 1-3:1.
• a fabric comprising non cellulosic fibres, optionally with cellulosic ones, is treated with an impregnation solution comprising a water soluble condensate of the organophosphorus compound and a bifunctional nitrogen compound such as urea.
• these compounds are present in a molar ratio of 1:0.25-0.6.
• Subsequent curing of said fabric is by means of heat, and preferably also ammonia.
• the impregnation solution contains the organophosphorus compound and the nitrogen compound, unreacted or reacted completely or in part.
• the concentration of organophosphorus compound in the aqueous solution may be 5-70% eg 5-35% or 35-70% (expressed by weight as THP+ ion), but is preferably 20-35%.
• the solution may contain a wetting agent such as a nonionic one,eg in amount of 0.05-0.5% by weight of the impregnation solution, a fabric softener such as a polyethylene one and in preferred amount of 0.1-2% by weight, and a salt of a strong acid and weak base (such as an ammonium or alkaline earth metal chloride or nitrate or ammonium acid phosphate) as catalyst for the heat cure, and in amount of 0.1-5% by weight.
• a wetting agent such as a nonionic one,eg in amount of 0.05-0.5% by weight of the impregnation solution
• a fabric softener such as a polyethylene one and in preferred amount of 0.1-2% by weight
• a salt of a strong acid and weak base such as an ammonium or alkaline earth metal chloride or nitrate or ammonium acid phosphate
• the treated substrate is impregnated to give an organo phosphorus pick up of less than 40% e.g. 10-40%; (such as 10-30%), especially 20-30% (as THP ion based on the original weight of the substrate).
• the substrate can be impregnated with solution and the wet substrate, e.g. fabric-usually squeezed to a wet pick up of 50-130%, e.g. 60-100% (based on the original weight of the substrate).
• the treated substrate may be impregnated with a concentrated impregnation solution via a minimum add-on, eg foam, technique and a 10-50% wet pick up.
• the organophosphorus impregnated substrate is then dried and heat cured either in two separate operations or one continuous operation. Drying may be in a stenter oven or over heated cans, e.g. steam cans and may involve heating at 80-160°C for 10 min to 10 secs eg at 100°C to 120°C for 3 min to 30 secs. Heat curing may be in a stenter or baking oven at a temperature of at least 100°C e.g. at 100-200°C or 100-180°C (such as 130-170°C) for 10-0.5 minutes e.g. 7-1 minutes. Higher temperature with long curing times should be avoided with substrates containing at least a majority of cellulosic fibres especially 100% cotton.
• the substrate is further cured by treatment with ammonia, usually gaseous ammonia, which diffuses through the substrate and/or is forced through the substrate e.g. by passage of the fabric over a perforated tube through which ammonia has is emitted.
• ammonia usually gaseous ammonia
• the ammonia cure may precede the heat cure, or the curing may be by heat alone, but preferably the ammonia cure takes place after the heat cure.
• the cured substrate usually has solids add-on of 10-50% or 10-40% e.g. 10-30% e.g. 10-25% or 15-30% especially 20-30%, (by weight of the original substrate), based on a total organophosphorus compound pick up of 16-36%, e.g. 20-28% (expressed as THP ion on the same basis).
• the cured substrate is then usually subjected to at least one of the following operations: further insolubilization of the cured resin in the treated substrate, oxidation (in order to convert at least some trivalent phosphorus to pentavalent phosphorus in the cured resin), or washing with aqueous base and washing with water.
• the oxidation may be performed with a gas containing molecular oxygen, preferably air, and particularly with the gas being drawn or blown through the substrate; thus the substrate in the form of fabric can be passed over a vacuum slot or perforated tube though which the gas is blown or sucked.
• a gas containing molecular oxygen preferably air
• the substrate in the form of fabric can be passed over a vacuum slot or perforated tube though which the gas is blown or sucked.
• the cured substrate may be washed with an aqueous medium, preferably an aqueous solution of a base, e.g. sodium carbonate, and/or rinsed with water.
• a base e.g. sodium carbonate
• the oxidation preferably reduces the residual content of formaldehyde on the cured substrate.
• the cured substrate may simply be rinsed with water or submitted to other operations to reduce its content of water soluble materials.
• the cured fabric is dried, to give a final substrate.
• the final substrate e.g. fabric
• workwear such as overalls, boiler suits and protective clothing including uniforms, particularly from 30-70% (e.g. 55-70%) cotton and 70-30%, (e.g. 45-30%) polyester, and household fabrics such as sheets and curtains particularly from 30-70% (e.g. 30-60%) cotton and 40-70% polyester.
• Processes of the invention with heat and ammonia cure usually give better flammability results, with fabrics comprising non cellulosic fibres, than are obtained with just ammonia cure thereby enabling fabrics to pass more severe flammability tests eg BS6249 (1989) than otherwise.
• the cured substrates obtained by the process of the invention may also have less reduction in strength.
• Fabrics A, B and C were impregnated to about 55-95% wet pick up with an aqueous solution at pH 4.5 of a precondensate of THP chloride and urea in a molar ratio of 1:0.5, the solution containing an amount of precondensate corresponding to 25.2% by weight THP+ ion.
• the impregnated fabric was then dried for 1.5 minutes in an oven at 100°C, and then heat cured under conditions specified below. In Ex 8 after the heat cure, the water content of the fabric was returned to normal by equilibration in a humidity controlled room overnight.
• the heat cured fabric of Ex 8 was then cured further with ammonia gas, which was passed through the fabric in a chamber and in a manner as described in USP 4145463; the cure time was 4 sec.
• the fabric was oxidized for 5 min in 5% aqueous hydrogen peroxide solution, washed for 5 mitt at 60°C in 2g/l sodium carbonate solution and rinsed for 5 mins with cold water. The rinsed fabric was then dried to give a final fabric.
• the final fabric was then analysed for P and N and tested for flame retardancy according to BS 5438 (1989) test 2A; in the case of Ex 1 and 4-6 the fabric was also tested after washing 50 times at 93°C, the washing being as in the manner described in DIN 53920 procedure 1 with soft water.
• the results were as follows: The corresponding char lengths for the final fabrics of Ex 4-6 after 50 washes were 85, 48 and 65 mm respectively.
• the cure efficiency was the percentage of final cured solids to the applied solids pick up.
• the P efficiency was the percentage of P in the final fabric to the P applied to the fabric.
• Fabric D was impregnated with an aqueous solution of 1:2 molar condensate of urea and tetrakis (hydroxymethyl) phosphonium chloride as described in Ex 1-8 and the excess of liquid squeezed from the fabric.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=10674402

Family Applications (1)

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Cited By (5)

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Citations (3)

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• 1990
  • 1990-04-12 GB GB909008420A patent/GB9008420D0/en active Pending
• 1991
  • 1991-04-02 GB GB9106867A patent/GB2242916A/en active Pending
  • 1991-04-02 EP EP91105140A patent/EP0451663A1/en not_active Withdrawn
  • 1991-04-03 CA CA002039634A patent/CA2039634A1/en not_active Abandoned
  • 1991-04-05 ZA ZA912552A patent/ZA912552B/xx unknown
  • 1991-04-11 FI FI911744A patent/FI911744A/fi not_active Application Discontinuation
  • 1991-04-11 NO NO91911429A patent/NO911429L/no unknown
  • 1991-04-11 AU AU74282/91A patent/AU7428291A/en not_active Abandoned
  • 1991-04-11 IE IE121691A patent/IE911216A1/en unknown
  • 1991-04-12 PL PL28986791A patent/PL289867A1/xx unknown
  • 1991-04-12 BR BR919101495A patent/BR9101495A/pt unknown
  • 1991-04-12 CN CN91102526A patent/CN1063914A/zh active Pending
  • 1991-04-12 JP JP3080086A patent/JPH04222276A/ja active Pending
  • 1991-04-12 CS CS911049A patent/CS104991A2/cs unknown
  • 1991-04-12 HU HU911224A patent/HUT57294A/hu unknown
  • 1991-04-12 PT PT97360A patent/PT97360A/pt not_active Application Discontinuation
  • 1991-04-12 KR KR1019910005861A patent/KR920005742A/ko not_active Application Discontinuation

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