Classifications

• • 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
  • D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof

Definitions

• This invention relates to a method of forming a woven fabric and to a woven fabric itself.
• the invention is particularly concerned with narrow fabric in the form of webbing that may be used for seat belt safety harnesses and in other applications.
• This Y last-mentioned webbing attempts to solve the problem by using monofilament weft yarns in the webbing construction. While such monofilaments give an acceptable degree of stiffness in the lateral direction of the webbing, problems do arise because the monofilament wefts tend to slip over the warp yarns within the fabric so causing distortion and eventual breaking of the monofilaments, particularly at the end of the webbing. Additionally, flex fatigue of monofilament yarns could lead to fracture of those yarns.
• the present invention seeks to solve this problem and to provide a commercially acceptable woven fabric having lateral stiffness such that it is suitable for use in, for example, seat belt safety harnesses, industrial safety harnesses and lifting slings.
• a method of forming a woven fabric comprises interweaving polyester warp yarns with a plurality of weft yarns, at least some of the weft yarns being polyamide multifilament yarns impregnated with a non-cross-linked homopolymer or copolymer of acrylic acid, and after weaving subjecting the fabric to heat treatment to cause the impregnating agent to cross-link and chemically bond to the polyamide yarns.
• a woven fabric comprising polyester warp yarns interwoven with weft yarns at least some of which are polyamide multifilament yarns stiffened by a cross-linked homopolymer or copolymer of acrylic acid chemically bonded to the polyamide yarns, but not to the polyester yarns.
• the particular selection of yarns and impregnating material used in the invention produces woven fabric having the required qualities.
• the use of multifilament weft yarns overcomes the slipping and potential fracture problems experienced with monofilament constructions.
• the cross-linked homopolymer or copolymer of acrylic acid that is used as the impregnating agent cross-links and chemically bonds only to the polyamide weft yarns, thus materially affecting the stiffness of those yarns. It does not chemically bond to the polyester warp yarns and indeed the degree of mechanical bonding to the warp yarns that may occur is low and, for practical purposes, negligible. Accordingly, the lateral stiffness and also the lateral crease recovery are significantly improved while the required longitudinal flexibility of the webbing is not materially affected.
• the stiffness that is imparted to the webbing is of a springy nature rather than a rigid nature. This is particularly advantageous as a laterally rigid webbing will tend to cut the wearer and be uncomfortable in use, while a laterally springy webbing will give somewhat in use and so be more comfortable.
• Control of the degree of lateral stiffness imparted to the fabric can be effected by selection of the incidence of impregnated weft yarns in the fabric, and preferably at least one in every successive four weft yarns is an impregnated, polyamide multifilament yarn. Control may also be effected by controlling the weight of impregnating agent present on the polyamide weft yarns, and desirably this ranges from 4% to 10% of impregnating agent by weight of yarn. A weight of 4% to 7% is particularly preferred, with 5% to 6% being the presently used range.
• the impregnating agent is a homopolymer of acrylic acid it can conveniently have a molecular weight within the range of 50,000 to 300,000 and an activity within the range of 20% to 50%.
• the additional monomer may conveniently be methacrylic acid, desirably present in no more than 85% by weight.
• Preferred copolymers again have an activity within the range of 20% to 50%.
• the polyamide yarn Prior to weaving, the polyamide yarn is conveniently impregnated by passing the yarn through a solution of the impregnating agent, and subsquently drying it at a temperature not exceeding 125°C. Below this temperature the only effect of the drying process is to off excess solvent and m curing or cross-linking of the impregnating agent occurs.
• the heat treatment of the woven fabric is then desirably effected at a temperature of from 132°C to 250°.C with a dwell time of from 1 to 4 minutes.
• Webbing in accordance with the invention is desirably woven on a conventional high speed needle loom. Any suitable weave pattern may be used, the commonest being a twill or a plain weave.
• Polyamide, for example nylon type 6 or 66, multifilament yarns destined for use as the weft yarns in the weaving process are passed through a bath containing a solution of the impregnating agent to be used.
• the preferred solvent is water, but non-aqueous systems may be used using, for example, methanol, ethanol or iso-propyl alcohol as solvent.
• the impregnated yarns are dried at a temperature not exceeding 125°C in order to dry the solvent off. When fully dry they are cooled and then held at a temperature that must not exceed 100°C.
• the weft yarns Prior to weaving, the weft yarns are coated with any suitable lubricant conventionally used in weaving in order to provide them with a surface friction sufficiently high to facilitate weaving on the high speed needle loom.
• the fabric is then woven from the polyester warp yarns, which may be either monofilament, or more preferably multifilament, from the lubricated and impregnated polyamide multifilament weft yarns and from other weft yarns if required, lubricated as necessary.
• a laterally stiff fabric will result from the use of impregnated polyamide yarns for all the weft yarns.
• impregnated yarns are woven alternately with other weft yarns, for example polyamide multifilament yarns that have not been impregnated, then a somewhat less laterally stiff webbing will be produced. Similarly, if only one weft yarn in three or one weft yarn in four is an impregnated yarn even lower lateral stiffness will be imparted. The less stiff webbings, although perhaps not suitable for motor vehicle use, nevertheless form webbings having very desirable properties for industrial safety harnesses.
• the fabric may be dyed if required, and then passed to an oven where it is heat treated at a temperature of from 130 0 C to 250°C for a dwell time of from 1 to 4 minutes, shorter dwell times being needed at higher temperatures.
• the presently preferred temperature is 220°C.
• the heat treatment causes cross-linking of the impregnating agent and chemical bonding of this to the polyamide yarns. Accordingly, the polyamide yarns are stiffened to give them a spring-like stiffness, so imparting a springy lateral stiffness to the webbing.
• the acrylic acid homopolymer or copolymer does not chemically react with the polyester warp yarns, and indeed there is found to be a minimal bonding of the polymer to the warp yarns.
• the effect of the polymer is to enhance the lateral stiffness of the webbing without significantly reducing the longitudinal flexibility thereof.
• Nylon type 6 weft yarns were passed through a bath containing an aqueous solution of a homopolymer of acrylic acid having a molecular weight of 250, 000 diluted to an activity of 5% and dried. Conditions were regulated to give a dry weight increase on the yarn of 5%.. Two ends of the yarn were used as the weft yarns in the weaving process.
• the webbing had the following properties:
• Example 2 The procedure of Example 2 was repeated, except that the bath contained an aqueous solution of a homopolymer of acrylic acid having a molecular weight of 75, 000.
• the webbing had the following properties:
• Example 2 The procedure of Example 2 was repeated, except that the bath contained an aqueous solution of a copolymer of 75% by weight methacrylic acid and 25% by weight acrylic acid.
• the webbing had the following properties:
• webbings i.e. the weft stiffness
• Such webbings are particularly suitable for use as vehicle safety harnesses.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Woven Fabrics (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=10541155

Family Applications (1)

Country Status (2)

Cited By (3)

Family Cites Families (4)

• 1983
  • 1983-04-15 GB GB838310233A patent/GB8310233D0/en active Pending
• 1984
  • 1984-04-09 EP EP84302412A patent/EP0123472A3/fr not_active Withdrawn

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