Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
  • D04H1/587—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives characterised by the bonding agents used
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
  • D04H1/64—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives the bonding agent being applied in wet state, e.g. chemical agents in dispersions or solutions
  • D04H1/645—Impregnation followed by a solidification process
• • 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
  • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/285—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acid amides or imides
• • 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
  • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/285—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acid amides or imides
  • D06M15/29—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acid amides or imides containing a N-methylol group or an etherified N-methylol group; containing a N-aminomethylene group; containing a N-sulfidomethylene group
• • 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
  • D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06M15/327—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated alcohols or esters thereof
  • D06M15/333—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated alcohols or esters thereof of vinyl acetate; Polyvinylalcohol

Definitions

• This invention relates to compositions based on copolymer emulsions which are used to bind together non-woven fibrous materials. More particularly, this invention relates to non-woven materials bonded with a binder composition comprising a copolymer emulsion and N-(n-butoxymethyl) acrylamide (NBMA) as a post polymerisation cross-linking agent.
• NBMA N-(n-butoxymethyl) acrylamide
• Non-woven fibrous material comprises a consolidated mass of fibres which may be laid down by mechanical, chemical, pneumatical, electrical or vacuum means and deposited in a desired flat shape, for example as webs, mats or sheets, or in a three dimensional form.
• the fibres may be natural or synthetic or a combination. In general the fibres to be used will be selected to suit the desired end use of the non-woven product.
• fibres may be derived from wood, i.e. cellulose, or may be cotton, glass, asbestos, rayon, wool, viscose, etc.
• the fibres may be deposited in a random manner, or may be positioned or aligned along particular axes.
• the non-woven product may contain layers of fibres oriented in a cross-layered manner to provide a uniform strength across the product.
• One route to binding the product is to introduce a binding composition during or after formation of the product.
• a binding composition during or after formation of the product.
• the means of application of the binding composition may be by, e.g. dipping, soaking or spraying.
• Subsequent treatment usually by the application of heat, dries the binding composition and gives structural integrity to the product.
• Bound non-woven fibre products are useful e.g. as curtains, in furniture, as drapes, filters, packaging, wiping cloths, fabric interlining for clothes, and industrial sealing material such as gaskets.
• a particular market is in the use of non-woven padding as absorbents in, e.g. babies nappies (diapers), female sanitary products etc.
• copolymer emulsions As binding compositions for non-woven fibrous materials.
• a particularly suitable base for binding compositions is copolymer emulsions obtained by polymerising unsaturated monomers in an emulsion system. Suitable copolymer emulsions may be obtained by means of processes performed at ambient pressure or under elevated pressure, e.g. up to 120 bars.
• Copolymer emulsion compositions suitable for this purpose will usually contain a monomer capable of cross-linking in a post-polymerisation step. Thus the copolymer emulsion will be applied to the non-woven product and first subjected to heating to remove water. Then in a further heating step the cross-linkable monomer cross-links to provide a three dimensional copolymer network with strength sufficient to provide structural integrity.
• cross-linkable monomer used is required to have an appropriate cross-linking efficiency as well as appropriate wet, dry and solvent strengths. Additionally, there has been a general desire to reduce the formaldehyde content in non-woven products, in particular those designed for human contact, e.g. babies nappies. Formaldehyde may be generated by the cross-linking reaction and may also be present in the fibrous components of the non-woven product.
• US 4,449,978 discloses a non-woven product comprising a non-woven web of fibres bonded together with a binder which comprises an interpolymer of vinyl acetate / ethylene / N-methylol acrylamide / acrylamide containing 5 to 40% by weight of ethylene, 1.75% to 3.5% by weight of N-methylol acrylamide (NMA) and 1.25% to 8.25% by weight of acrylamide.
• NMA N-methylol acrylamide
• WO 92/08835 discloses a binding composition for non-woven fibrous materials comprising a copolymer emulsion based on vinyl alkanoate and using N-(n-butoxymethyl) acrylamide (NBMA) as a post polymerisation cross-linking agent to reduce formaldehyde emission.
• NBMA N-(n-butoxymethyl) acrylamide
• the more NBMA is added the more formaldehyde is produced during the cross-linking reaction and the more residual formaldehyde is present in fabrics.
• NBMA content is below 3% by weight.
• An other advantage of such a composition would be a significant cost reduction since NBMA is a quite expensive product.
• NBMA as a post polymerisation cross-linking agent gives rise to some problems when the amount of NBMA (in % by weight of the total monomer content) is low, i.e. below 3%. More particularly, the runnability of the process, more specifically the roller stability, is poor. In other respects, the wet, dry and solvent strengths prove to drop dramatically.
• NBMA-containing binding composition for non-woven fibrous materials which maintains good runnability as well as good wet, dry and solvent strengths whereas the NBMA content is below 3% by weight.
• Preferably not more than 90% by weight, more preferably between 60 and 80% by weight, of the monomer content is C1 to C4 alkanoate, with the preferred material being vinyl acetate.
• the copolymer emulsion may include a C2 to C4 alkylene monomer, e.g. ethylene, typically in an amount of from 5% to 40% by weight of total monomer.
• Another possible comonomer is selected from the alkyl (C2 to C10) (meth) acrylate class e.g., butylacrylate or 2 ethyl hexyl acrylate, which will preferably be present in an amount of from about 10% to about 60% by weight of total monomer.
• alkyl (C2 to C10) (meth) acrylate class e.g., butylacrylate or 2 ethyl hexyl acrylate, which will preferably be present in an amount of from about 10% to about 60% by weight of total monomer.
• a further class of possible functional comonomer is carboxyl group-containing monomers, e.g. acrylic acid, methacrylic acid, crotonic acid, itaconic acid, etc.
• Sodium vinyl sulphonate is a further example of a functional monomer that may be included. Preferably between 0.2% to 1% by weight of total monomer is added.
• One or more surfactants may be included as appropriate.
• copolymer emulsion can be prepared using generally conventional techniques which are well known and characterised in the literature. Polymer synthesis (volumes I & II) by Sandler & Karo (Academic Press 1974) and Preparative Methods of Polymer Chemistry (2nd Edition) by Sorensen & Campbell (Interscience 1968) provide preparative information. Methoden der Organischen Chemie (Houben-Weyl) Band XIV published by Georg Thieme Verlag Stuttgart (1961) also provides preparative descriptions.
• Any suitable initiator system can be used, but it is preferred not to use formosul (sodium formaldehyde sulphoxylate) as this produces formaldehyde. It is preferred to use either a thermal polymerisation, with no reducing agent, e.g. using ammonium or alkali metal persulphates, or redox initiation, with a persulphate, hydrogen peroxide or an organic peroxide as the oxidising agent and with the reducing agent typically being ascorbic acid or sodium metabisulphite.
• reducing agent e.g. using ammonium or alkali metal persulphates, or redox initiation
• the binding composition of the invention can be used for binding non-woven fibrous materials in generally conventional manner, e.g. by dipping, soaking, or spraying or by use of rollers and a bath.
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 66.5 Ethylene (E) 30.0 Acrylic Acid (AA) 0.5 N-butoxymethylacrylamide (NBMA) 1.5 Acrylamide (AMD) 1.0 Sodium vinyl sulphonate (SVS) 0.5
• An initial aqueous phase consisting of deionised water, (800 g), Empimin OT (37.5 g), formic acid (0.3 g), ascorbic acid (0.4 g), ferric chloride (0.9 g of a 1% solution), was charged to a 4 litre stainless steel reactor.
• the reactor was sealed, purged twice with nitrogen and once with ethylene.
• the reactor was pressurized with ethylene to 870 psi and then heated to between 32-34°C.
• Empimin OT used in the examples is a 60% active solution of sodium di-octyl sulphosuccinate obtainable from Surfachem Ltd., Leeds, U.K..
• Synperonic NP30 (70% active) used in the examples is nonyl phenol, nonionic containing 30 ethylene oxide units, obtainable from Cargo Fleet Chemicals U.K..
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 76.4 Ethylene (E) 20.6 Acrylic Acid (AA) 0.5 N-butoxymethyl acrylamide (NBMA) 1.5 Acrylamide (AMD) 1.0
• a solution of 103g of Synperonic NP30, (70% active), and 4.0g of Perlankrol PA (in 750.5g of deionised water), and a monomer mixture consisting of 67g of vinyl acetate and 0.45g of acrylic acid were charged to a 4 litre stainless steel reactor. The temperature was raised to 30°C, then the reactor was purged twice with nitrogen and once with ethylene. The reactor was charged with ethylene to a pressure of 50 bar, and then heated to a temperature of 75°C. At this temperature 15% of a solution of sodium persulphate (9.0g in 275g of water) was added to the reactor.
• the temperature was reduced to 50°C and solutions of t-butylhydroperoxide, (3.6g in 70g of water), and sodium metabisulphite, (2.4g in 70g of water), were added over 30 minutes while cooling to 30°C.
• a solution of 1.8g of Kathon LXE in 48.2g of water was added.
• the emulsion was discharged from the reactor and filtered through 250 mesh nylon to remove coagulum.
• the resultant latex has a solids content of 56.45% and a viscosity of 312 centipoise.
• Perlankrol PA used in the examples is (92% active) anionic based on sulphated nonyl phenol with 3-4 ethylene oxide units, obtainable from Lankro Chemicals Ltd., U.K..
• Kathon LXE is obtainable from Rohm and Haas.
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 66.0 Veova 9 30.0 Acrylic Acid (AA) 0.5 NBMA 2.0 Acrylamide (AMD) 1.0 Sodium vinyl sulphonate (SVS) 0.5
• Veova 9 is a vinyl ester of versatic 9, a carboxylic acid, and is obtainable from Shell Chemicals Ltd. U.K..
• the initial waterphase consisting of deionised water (250g), Empimin OT (10.4g), formic acid (0.03g), Ascorbic acid (0.1g), Ferric chloride (0.25g of a 1% solution), was charged to a 1 litre glass reactor. The reactor was purged with nitrogen and a slow purge continued during the reaction. The reactor was heated to between 32-34°C.
• a monomer mixture consisting of vinyl acetate (16.5g), acrylic acid (0.12g), NBMA (0.51g), and Veova 9 (7.5g) was added followed by the aqueous phase monomer addition of deionised water (4.5g), Empimin OT (0.52g), synperonic NP30 (0.36g), sodium vinyl sulphonate (0.8g), acrylamide (0.25g), and ammonia (0.17g).
• the reactor was cooled to around 30-32°C, and the additions of tertiary butyl hydroperoxide (1.0g) in deionised water (11.3g) and of sodium metabisulphite (0.6g) in deionised water (11.3g) were started. At the end of the additions the reactor was cooled to below 30°C. the emulsion was discharged from the reactor and filtered using 250 mesh. The emulsion had a solids content of 51.85% and viscosity of 330 centipoise, as measured by the method described previously.
• the manufacturing process is exactly the same as for example 3 except that instead of using 2% NBMA, in this example 1.5% of NBMA was used, vinyl acetate being increased to 66.5%.
• the latex properties were solids content 51.85%, and viscosity of 500 centipoise.
• the manufacturing process is again the same as for example 3, except that the acrylamide level was increased to 1.5%, whilst the NBMA content was at 1.5%.
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 72.0 Ethylene (E) 25.0 Acrylic Acid (AA) 0.5 NBMA 2.0 Sodium vinyl sulphonate (SVS) 0.5
• the product was prepared in a 50 gallon reactor.
• the initial waterphase consisting of deionised water (60.0Kg), Empimin OT (3.7kg), formic acid (0.03kg), Ascorbic acid (0.035Kg), Ferric chloride (0.006Kg of a 1% solution), was charged to a 50 gallon stainless steel reactor.
• the reactor was sealed purged twice with nitrogen and once with ethylene.
• the reactor was pressurized with ethylene to 870 psi and then heated to between 32-34°C.
• a monomer mixture consisting of vinyl acetate (6.4Kg), acrylic acid (0.045Kg), and NBMA (0.17Kg), was added followed by the aqueous phase monomer addition of deionised water (2.0Kg), Empimin OT (0.18Kg), synperonic NP30 (0.12Kg), sodium vinyl sulphonate (0.17Kg), and ammonia (0.02Kg).
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 76.5 Ethylene (E) 20.5 Acrylic Acid (AA) 0.5 NBMA 1.5 Sodium vinyl sulphonate (SVS) 1.0
• a solution of 10.5kg of Synperionic NP30, (70% active), and 0.40kg of Perlankrol PA (in 98kg of deionised water) and a monomer mixture consisting of 7.0kg of vinyl acetate and 0.056kg of acrylic acid were charged to a 50 gallon reactor.
• the reactor was purged three times with nitrogen and once with ethylene.
• the reactor was charged with ethylene, (12.5kg), to a pressure of 40 bar, then 15% of a solution of sodium persulphate, (0.92kg in 19kg of water), was added to the reactor.
• the temperature was raised to 70°C, and then allowed to exotherm to 75°C.
• the temperature was reduced to 50°C and solutions of 0.37kg of t-butylhydroperoxide plus 0.09kg of ammonia in 6.0kg of water and sodium metabisulphite, (0.24kg in 6.0kg of water), were added over 30 minutes while cooling to 30°C.
• a solution of 1.86kg of citric acid in 2.0kg of water and a solution of Kathon LXE, (0.12kg in 0.5kg of water) were added.
• the emulsion was discharged from the reactor and filtered through 250 mesh nylon to remove coagulum.
• the resultant latex had a solids content of 55.80%, viscosity of 78 centipoise.
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 65.5 Ethylene (E) 30.0 Acrylic Acid (AA) 0.5 N-methylolacrylamide (NMA) 4.0
• the initial waterphase consisting of deionised water (800g), Empimin OT (37.5g), formic acid (0.3g), formosul (0.4g), Ferric chloride (0.9g of a 1% solution), was charged to a 4 litre stainless steel reactor.
• the reactor was sealed purged twice with nitrogen and once with ethylene.
• the reactor was pressurized with ethylene to 870 psi and then heated to between 32-34°C.
• a monomer mixture consisting of vinyl acetate (60g), acrylic acid (0.45g), was added followed by the aqueous phase monomer addition of deionised water (21.0g), Empimin OT (1.87g), synperonic NP30 (1.28g), NMA (7.5g), and ammonia (0.45g).
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 76.5 Ethylene (E) 20.0 Crotonic Acid (AA) 0.5 N-methylolacrylamide (NMA) 3.0
• a solution of 103g of Synperonic NP30 (70% active), 1.36g of ferric ion solution and 0.7g of formic acid in 750g of deionised water and a monomer mixture consisting of 67g of vinyl acetate and 0.45g of crotonic acid were charged to a 4 litre stainless steel reactor. The temperature was raised to 30°C, then the reactor was purged twice with nitrogen and once with ethylene. The reactor was charged with ethylene to a pressure of 57 bar. A monomer mixture consisting of 1274g of vinyl acetate and 8.45g of crotonic acid and a solution of 120g of NMA (45% aq.), and 5.0g of ammonia in 205g of water were added at a constant rate over 5 hours.
• Initiator solutions comprising 7.2g of ammonium persulphate in 300g of water and 2.2g of formosul in 300g of water were added at double rate for 20 minutes, normal rate for 4 hours 20 minutes and double rate for 1 hour to give a total addition time of 5 hours 40 minutes.
• the temperature was slowly raised to 60°C during the first 3 hours of additions and maintained until the monomer addition was complete, then it was raised to 70°C until the initiator additions were complete.
• the temperature was reduced to 50°C and solutions of t-butylhydroperoxyde (3.6g in 35g of water) and sodium metabisulphite (3.6g in 35g of water) were added over 30 minutes while cooling to 30°C.
• the emulsion was discharged from the reactor and filtered through 250 mesh nylon to remove coagulum.
• the resultant latex had a solids content of 49.7% and a viscosity of 470 centipoise.
• the monomer composition of this example was: % by weight Vinyl acetate (VA) 49.8 Butyl acrylate 46.0 Acrylic Acid (AA) 1.0 N-methylolacrylamide (NMA) 3.2
• Deionised water (109g) and ferric chloride (1.25g of a 0.1% solution) were placed in an open glass reactor vessel (1 litre), and purged with nitrogen to betweeen 20-22°C. A slow nitrogen purge was continued through out the reaction.
• the reaction was cooled to below 30°C and pH adjusted to between 4-5 using ammonia [(1.25g of a 0.88 concentration) in water (1.25g)]. This resulted a latex having a solids content of 35% and a viscosity of 200 centipoise.
• Gafec RE610 is a phosphate ester obtainable from GAF Ltd., U.K.
• roller stability suffers and, to improve the runnability, 0.5% of sodium vinyl sulphonate needed to be added (in Example 6) to improve the runnability, as according to the teaching of WO 92/08835. It can be seen that, for example 2, no sodium vinyl sulphonate has been added, nevertheless the roller stability is fair. It can also be noticed by comparing Examples 1 and 6 that, with the same amount of SVS being added, the roller stability is dramatically improved by the combination of NBMA and acrylamide. Therefore, if a very good roller stability is required it is enough to add a very little amount of SVS, preferably between 0.2% and 1% of total monomer.

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• Engineering & Computer Science (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• General Chemical & Material Sciences (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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Cited By (7)

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• 1994
  • 1994-02-01 EP EP94101495A patent/EP0609849A1/fr not_active Withdrawn

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