US3536556A - Liquid activated bonded polyamide articles - Google Patents

Liquid activated bonded polyamide articles Download PDF

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Publication number
US3536556A
US3536556A US720614A US3536556DA US3536556A US 3536556 A US3536556 A US 3536556A US 720614 A US720614 A US 720614A US 3536556D A US3536556D A US 3536556DA US 3536556 A US3536556 A US 3536556A
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United States
Prior art keywords
bonding
gas
fabric
filaments
liquid
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Expired - Lifetime
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US720614A
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English (en)
Inventor
Philip J Stevenson
John T Sparrow
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Monsanto Co
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Monsanto Co
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
    • C07D201/02—Preparation of lactams
    • C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
    • 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
    • D04H1/54—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 welding together the fibres, e.g. by partially melting or dissolving

Definitions

  • a continuous process for producing non-woven fabric from polyamide filaments includes the forming of a mass of randomly disposed filaments and contacting the filaments with a liquid which is comprised of an activating gas dissolved in an organic liquid solvent carrier in which the gas remains substantially unionized with the liquid carrier being inert to the polyamide filaments.
  • the removal of the dissolved gas from the filaments causes cohered adjacent filament to bond to each other to form a non-woven sheet of randomly disposed and interconnected polyamide filaments.
  • This invention relates to the production of non-woven fabrics and, more specifically, to a process for forming a non-woven sheet from polyamide filaments by bonding touching filaments together at the points of intersection by contacting the filaments with a gas, dissolved in an organic liquid carrier, which disrupts the interchain hydrogen bonding between adjacent amide groups with-out breaking the covalent bonds within polyamide chains so that upon removal of the gas from the polyamide filaments, hydrogen bonding occurs between the molecular chains comprising the different filaments.
  • Solvent bonding by the prior art methods is not easily controlled and frequently tends to alter the aesthetic properties of the resulting Web.
  • solvent bonding it is difiicult to achieve adequate adhesiveness between the fibers without dissolving the entire web or, at least, without significantly imparing the physical properties of the web.
  • the bonds between the touching filaments frequently have a swollen appearance or evidence redisposition of the polymer which is generally referred to as polymer migration. In most instances, these swollen areas. around the bonds do not possess the same dye acceptance level because of changes in the crystalline structure which is localized at the bond site thereby causing non-uniform dyeing.
  • the filaments which may be either continuous or staple, are contacted with a liquid which is comprised of a gas having been dissolved in a non-ionizing organic liquid solvent.
  • the liquid solvent is chemically inert to the polyamide filaments and serves as a carrier for the gas.
  • the molecules of the dissolved gas disrupt the interchain hydrogen bonding between adjacent amide groups without breaking the covalent bonds within the polyamide chains so that upon removal of the gas from the polyamide filaments, the interchain hydrogen bonding between cohered units occurs between contiguous and touching filaments as well as between the molecular chains comprising the body of the filaments.
  • the batt of non-woven filaments may be formed in a variety of ways. If the filaments are in staple form, a batt may easily be made by means of a Rando-Webber or by means of a conventional textile carding system. Alternatively, if the filaments are of very short lengths, webs may be formed from a dispersion in water as in paper making processes. If the batt is to be comprised of continuous polyamide filaments, the batt may be formed by the known method of passing the filaments through an aspirator jet which forces the filaments downwardly and onto a conveyor belt. The aspirator jet randomly disposes the filaments on the belt so that there is substantially no difference in the machine, transverse and bias directions in regard to the physical properties of the batt.
  • the activating gases which may be dissolved in a suitable solvent to form the bond-inducing liquid include hydrogen chloride, hydrogen bromide, boron trifluoride, boron trichloride, chlorine, sulfur trioxide, nitrogen trioxide, nitrogen dioxide and other related gases which do not significantly degrade the fiber but, while in contact with the fiber, disrupt the interchain hydrogen bonds between the adjacent amide groups.
  • Solvents carriers as used herein relate to solvents for the activating gases and include acetone, ether, chloroform, carbon tetrachloride, benzene, pentane, heptane, trichlorofiuoromethane and other like organic liquids in which the gas remains substantially unionized and which are chemically inert to polyamide filaments.
  • the bonding liquid may be prepared by bubbling the gas into the organic liquid solvent carrier for a selected interval of time.
  • the bonding of adjacent filaments is initiated by immersing the batt into the bonding liquid. As the gas concentration in the liquid carrier increases, the web strength increases as stronger and possibly more bonds are formed until fiber breakage begins to play a significant part in the fabric rupture mechanism.
  • the interfilament bonds are stabilized by removing the activating gas from the batt which may be accomplished either by evaporating the liquid from the batt or by washing the batt in water or the like.
  • the process of this invention is applicable to substantially all nylons or polyamide articles including nylon '66, nylon 6', nylon 11 and the like.
  • FIG. 1 is a graph showing fabric tenacity plotted against the concentration of hydrogen chloride in the solvent
  • FIG. 2 is a graph showing the performance ratio, which is the ratio of breaking strength to bending length plotted against the concentration of the hydrogen chloride gas in the liquid solvent;
  • FIG. 3 is a graph showing zero span tenacity plotted against the concentration of the hydrogen chloride gas in the liquid solvent
  • FIG. 4 is a graph showing the quality ratio plotted against the concentration of the hydrogen chloride gas in the liquid solvent
  • FIG. 5 is a graph showing the bending length of the fabric plotted against the concentration of the hydrogen chloride gas in the liquid solvent
  • FIG. 6 is a graph showing the initial modulus of the fabric plotted against the concentration of the hydrogen chloride gas in the liquid solvent
  • FIG. 7 is a graph showing the bonding efficiency, which is the ratio of normal span tenacity to zero span tenacity expressed as percent, plotted against the concentration of the hydrogen chloride gas in the liquid solvent.
  • FIG. 8 is a graph showing the percent elongation of the fabric plotted against the concentration of the hydrogen chloride gas in the liquid solvent.
  • the invention as herein set forth includes a process for bonding touching synthetic linear aliphatic polyamide articles which may be in the form of filaments, pellicles, granules and the like along their contiguous surfaces.
  • Synthetic linear polyarnides have in their structure recurring NHCO- groups. The mechanism of bonding is that the gases which have been absorbed in the solvent liquid form complexes with the NHCO groups which disrupt the hydrogen bonds between the polymer chains.
  • bonds form cross links between the molecular chains, thus increasing such properties as melting point and tensile strength. Therefore, when these bonds are disrupted by the action of the activating dissolved gases, the polymer chains within the structure and especially along the surface thereof become more flexible and tend to shift to relieve the stresses caused by tension or pressure on the structure.
  • the complex formation is reversible and when the hydrogen chloride is desorbed, the hydrogen bonds reform. In the shifted position of the polymer chains, many of the new bonds formed are between the CO and the NH groups of different structures, such as, between adjacent granules and the like.
  • a standard batt which is comprised of a randomly disposed collection of polyamide continuous filaments having zero twist and having been stretched is cut into 9 inch squares.
  • the bonding liquid is prepared by bubbling into 1,000 cc. of chloroform for about 45 seconds hydrogen chloride at a rate of 450 cc. per minute, the resulting liquid having a hydrogen chloride concentration of 0.045 N.
  • Bonding is effected by saturating the batt with the bonding liquid, passing the saturated batt through a wringer to remove excess liquid, removing the bonding liquid from the batt by contacting the batt with hot nitrogen while the batt is held between two wire screens and removing the residual hydrogen chloride from the batt by washing in water.
  • a concentration of 0.045 N hydrogen chloride in chloroform gives excellent bonding, the fabric properties being set forth in Table I.
  • FIGS. 2 and 4 show the performance ratio and quality ratio, respectively, plotted against the molar concentration.
  • the performance ratio which is breaking strength measured in pounds per inch divided by the bending length of the fabric in inches is slightly biased in favor of heavy fabrics and will generally increase as the weight increases.
  • the quality ratio while including the pounds per inch of the performance ratio divided by the bending length in inches also includes the weight of the fabric in ounces per square yard. Therefore, where the weight of the fabric is increased, the quality ratio accounts for it and the ratio will thus be being slightly biased to light weight fabrics.
  • Bonding efficiency which is set forth in FIG. 7 is a ratio of the normal tenacity, measured at a span of five inches, of the fabric as set forth in FIG. 1 and the zero span tenacity of the fabric which is set forth in FIG. 3.
  • the results show a slight increase in bonding elficiency after a concentration of 0.045 N which is most likely due to the combination of stronger bonds being formed and to fiber degradation, fiber breakage playing a significant part in the rupture of the fabric beyond the optimum molar concentration.
  • EXAMPLE I A random Web of drawn continuous filament nylon immersed in, for about 5 seconds, a bonding medium prepared by bubbling gaseous hydrogen chloride into 1,000 cc. chloroform for 45 seconds at a rate of 450 cc./min. The web was passed through a manually operated roll type wringer to remove excess liquid after which it was placed between wire screens (21 ends/in.) and held under a pressure of 35 p.s.i.g. while nitrogen at a temperature of 60 C. was passed through the sample to evaporate the chloroform. The sample was subsequently washed with water to remove any residual traces of hydrogen chloride. Properties of the resulting fabric are as follows:
  • a web of drawn continuous filament nylon was treated in the same manner as in Example II except that a solution of hydrogen chloride in benzene was substituted for the solution of hydrogen chloride in acetone. The resulting product was strongly bonded and was not discolored.
  • EXAMPLE IV A sample of a web of non-woven drawn continuous filament nylon supported between two pieces of wire screen (21 ends per inch) was immersed in a solution of chloroform into which boron trifluoride had been bubbled. The saturated web was then placed in a press and subjected to a pressure of 35 p.s.i.g. while heated nitrogen was passed through the sample to remove the liquid. The web was then washed to remove any residual boron trifluoride and dried. Physical properties of the resulting product are as follows:
  • EXAMPLE IX A web of drawn continuous filament nylon was treated in the same manner as in Example II except that solution of sulfur trioxide in trichlorofluoromethane (Freon-11) was substituted for the solution of hydrogen chloride in acetone. The resulting product was strongly bonded and was not discolored. The fabric was heat treated in air at C. to remove any residual traces of sulful trioxide gas remaining in the polyamide filaments.
  • a process for mutually bonding synthetic linear polymeric articles along their contiguous surfaces, said polymeric articles having H I ll N linkages comprising the steps of contacting said articles with a medium, said medium being comprised of a gas dissolved in an organic liquid carrier in which said gas remains substantially unionized, said liquid carrier being inert to said polymeric articles while the molecules of said dissolved gas disrupt the intermolecular hydrogen bonds between adjacent H o 1L linkages without appreciably disrupting covalent bonds within the polymeric chains and causing contact between said articles and removing said dissolved gas and carrier from said articles while adjacent articles are in contact to bond said articles along said contiguous surfaces.
  • a process for bonding touching synthetic linear polyamide articles being in the form of filaments, pellicles, granules and the like along their contiguous surfaces comprising the steps of:
  • liquid being comprised of a gas dissolved in an organic liquid carrier in which said gas remains substantially unionized, said liquid carrier being inert to said polyamide articles while the molecules of said dissolved gas disrupt the interchain hydrogen bonding between adjacent amide groups without appreciably disturbing the covalent bonds within the polyamide chains;
  • organic liquid carrier is selected from the group consisting of acetone, ether, chloroform, carbon tetrachloride, benzene, pentane, trichlorofiuoromethane and heptane.
  • a process for forming a non-woven fabric from a batt comprised of randomly disposed polyamide filaments comprising the steps of:
  • non-ionic organic liquid carrier is selected from the group consisting of acetone, ether, chloroform, carbon tetrachloride, benzene, pentane, trichlorofluoromethane and heptane.
  • organic liquid carrier is selected from the group consisting of acetone, ether chloroform, carbon tetrachloride, benezene, pentane and heptane.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Nonwoven Fabrics (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Artificial Filaments (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Adhesives Or Adhesive Processes (AREA)
US720614A 1968-04-11 1968-04-11 Liquid activated bonded polyamide articles Expired - Lifetime US3536556A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US72061468A 1968-04-11 1968-04-11

Publications (1)

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US3536556A true US3536556A (en) 1970-10-27

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US720614A Expired - Lifetime US3536556A (en) 1968-04-11 1968-04-11 Liquid activated bonded polyamide articles

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US (1) US3536556A (de)
JP (1) JPS5015900B1 (de)
AT (1) AT314465B (de)
BE (1) BE731411A (de)
CH (1) CH558169D (de)
DE (1) DE1918580C3 (de)
ES (1) ES365921A1 (de)
FR (1) FR2006079A1 (de)
GB (1) GB1268071A (de)
IL (1) IL31993A (de)
LU (1) LU58382A1 (de)
NL (1) NL6905646A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3901755A (en) * 1972-05-24 1975-08-26 Cons Bathurst Ltd Bonding of polymers by surface activation
US4142016A (en) * 1975-03-03 1979-02-27 Monsanto Company Layered fabrics and processes for producing same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5419220U (de) * 1977-07-12 1979-02-07
JPS54104428U (de) * 1977-12-29 1979-07-23

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2869973A (en) * 1954-08-25 1959-01-20 Du Pont Synthetic paper sheet of chemically bonded synthetic polymer fibers and process of making the same
US2920992A (en) * 1954-09-22 1960-01-12 Du Pont Article of commerce

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2869973A (en) * 1954-08-25 1959-01-20 Du Pont Synthetic paper sheet of chemically bonded synthetic polymer fibers and process of making the same
US2920992A (en) * 1954-09-22 1960-01-12 Du Pont Article of commerce

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3901755A (en) * 1972-05-24 1975-08-26 Cons Bathurst Ltd Bonding of polymers by surface activation
US4142016A (en) * 1975-03-03 1979-02-27 Monsanto Company Layered fabrics and processes for producing same

Also Published As

Publication number Publication date
CH558169D (de) 1900-01-01
LU58382A1 (de) 1969-11-13
BE731411A (de) 1969-10-13
DE1918580B2 (de) 1978-07-13
FR2006079A1 (de) 1969-12-19
DE1918580A1 (de) 1969-10-30
GB1268071A (en) 1972-03-22
AT314465B (de) 1974-04-10
DE1918580C3 (de) 1979-03-15
IL31993A (en) 1972-07-26
ES365921A1 (es) 1971-03-16
NL6905646A (de) 1969-10-14
IL31993A0 (en) 1969-06-25
JPS5015900B1 (de) 1975-06-09

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