Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
• • 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
  • D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
  • D21H13/10—Organic non-cellulose fibres
  • D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H13/24—Polyesters

Definitions

• This invention concerns new water-dispersible synthetic polymer fiber, particularly of poly(ethylene terephthalate) , and its preparation.
• water-dispersible synthetic fiber especially of polyester.
• Such water-dispersible fiber is used in various non-woven applications, including paper-making and wet-laid non-woven fabrics, sometimes as part of a blend, often with large amounts of wood pulp, or fiberglass, but also in applications requiring only polyester fiber, i.e., unblended with other fiber.
• This use, and the requirements therefor are entirely different from previous more conventional use as tow or staple fiber for conversion into textile yarns for eventual use in woven or knitted fabrics, because of the need to disperse this fiber in water instead of to convert the fiber into yarns, e.g., by processes such as carding, e.g. in the cotton system. It is this requirement for water-dispersibility that distinguishes the field of the invention from previous, more conventional polyester staple fiber.
• water-dispersible polyester fiber is of poly(ethylene terephthalate), and is prepared in essentially the same general way as conventional textile polyester staple fiber, except that most water-dispersible polyester fiber is not crimped, whereas any polyester staple fiber for use in textile yarns is generally crimped while in the form of tow, before conversion into staple fiber.
• waterdispersible polyester fiber has generally been prepared by melt-spinning the polyester into filaments, combining the filaments to form a tow, drawing, applying a suitable coating to impart water-dispersible properties, generally in the same way as a finish is applied to a tow of conventional textile filaments, and then, generally without any crimping (or with imparting only some mild wavy undulations in some cases to provide extra bulk and a three-dimensional matrix), converting the tow into staple.
• Some prior polyester staple fiber has been prepared in uncrimped form, e.g. for use as flock in pile fabrics, but for such use, water-dispersibility has not been required.
• Polyester fibers are naturally hydrophobic, so it is necessary to apply to the polyester a suitable coating, as disclosed by Ring et al. in U.S. Patent No. 4,007,083, Hawkins in U.S. Patent Nos. 4,137,181, 4,179,543 and 4,294,883, and viscose Canal in British Patent No. 958,350, to.overcome the inherent hydrophobic character of the polyester fiber without creating foam or causing the fibers to flocculate. It is this coating that has distinguished water-dispersible polyester fiber from more conventional polyester staple fiber, rather than any inherent characteristic feature of the polyester itself, or of its shape, such as the cross-section.
• the cross-section of all commercial water-dispersible polyester fiber has been round. Indeed the cross-section of most commercial polyester staple fiber has generally been round, because this has been preferred.
• new synthetic polymer water-dispersible fiber especially polyester fiber, characterized in that the fibers are of cruciform cross-section.
• a cruciform cross-section has been used heretofore for other polyester fibers, as described herein.
• the water-dispersible fiber of the invention may be essentially similar to prior water-dispersible polyester or other synthetic polymer fibers, although the advantages described hereinafter may provide the opportunity for additional modifications.
• the invention will be described hereinafter with special reference to polyester fiber, although it will be recognized that other synthetic polymers, such as polyamides and polyolefins, may also be used.
• the fibers of the invention may be made conveniently by melt-spinning and drawing polyester • filaments of appropriate denier per filament (dpf), and applying thereto a suitable coating to impart water-dispersible characteristics. The filaments are then generally cut into staple of whatever length is desired for the end-use contemplated.
• dpf denier per filament
• cruciform cross-section for the water-dispersible fiber of the invention has, surprisingly, been found to promote dispersibility, in comparison with a round cross-section, and this imparts to the resulting wet-laid fibers better uniformity, more opacity, good permeability, and an attractive flannel-like hand as will be seen in the Example.
• Figure 1 shows a cruciform cross-section for a stylized fiber according to the invention.
• Figure 2 shows a typical spinneret orifice for spinning filaments of the invention.
• a cruciform cross-section has already been used for more conventional polyester staple fiber, that has been spun into filaments and drawn, cut, converted into spun yarn, and used in woven or knitted fabrics. Such fiber had the water-dispersible characteristics required for this invention.
• polyester filaments having a cruciform cross-section are already known from Lehmicke U.S. Pat. No. 2,945,739, which discloses a process for melt-spinning polyamide and polyester filaments of, inter alia cruciform cross-section, and woven and knitted fabrics from staple fibers, and from Jamieson U.S. Pat. No.
• polyester filamentary substrates for making the water-dispersible fiber of the invention may be prepared by the techniques described therein, or by appropriate modifications of- these or other known techniques of making polyester filaments of non-round cross-section.
• the prior art references disclose parameters for a cruciform cross-section and Figure 1 is essentially as shown therein.
• the preparation of the polyester staple fiber is otherwise conventional, involving the steps of melt-spinning polymer into filaments, collecting the filaments into a tow, drawing the tow, and applying a suitable coating water-dispersible to impart characteristics. If low shrinkage is desired, the drawn filaments are generally annealed.
• an appropriate coating to promote water-dispersibility is important, and more of such coating is generally required than for comparable weights of fiber of round cross-section of similar dpf, because of the larger surface area of the periphery of the cruciform cross-section. It is especially important to provide good boundary lubrication properties. For this reason, an ethoxylated coating is preferred.
• Suitable coatings are disclosed in Hawkins, U. S. Pat. Nos. 4,137,181, 4,179,543 and 4,294,883 and also in copending USSN 721,344, filed simultaneously herewith in the names of van Issum and Schluter, disclosing the use of a synthetic copolyester of poly(ethylene terephthalate) units and poly(oxyalkylene) of groups derived from a poly(oxyalkylene) glycol having an average molecular weight in the range of 300 to 6,000, as disclosed, e.g. in Mclntyre, et al. U.S. Pat. Nos.
• Such polyester fiber is generally prepared first in the form of a continuous filamentary uncrimped tow or, if extra bulk is required, and a more three-dimensional matrix, the filaments may be provided with mild wave-like undulations by a mild crimping-type process, and the uncrimped or mildly wave-like filaments are cut to the desired cut length, i.e. to form the water-dispersible fiber, which is generally sold in the form of bales, or other packages of cut fiber.
• Suitable cut lengths are generally from about 5 to about 90 mm (1/4 to 3 inches), generally up to 60 mm (2-1/2 inches), and of length/diameter (L/D) ratio from about 100:1 to about 2000:1, preferably about 150:1 to about 2000:1, it being an advantage of the invention that good performance has been obtainable with preferred water-dispersible fiber of the invention with an L/D ratio higher than we have considered satisfactory with prior art water-dispersible polyester fiber. For instance, machine manufacturers have generally recommended that the L/D ratio not exceed 500:1, and many operators have considered even this figure unrealistically high.
• a suitable denier per filament is generally from about 0.5 to about 20.
• the coating is generally present in amount about 0.04 to about 1.0% of the weight of fiber (OWF%), it being an advantage that smaller amounts may generally be used than we have considered satisfactory according to the prior art.
• OPF% weight of fiber
• the coating is preferably cured on the filaments by heating the coated filaments, or the resulting staple fiber, if desired, to a temperature of about 100° to about 190° to improve durability.
• Example 1 The following fibers, Fiber A, a comparison of round cross section, and Fiber N, a fiber of the invention of cruciform cross section, were both spun from
• Fiber A was spun at 1600 ypm into filaments with conventional radial air quenching using a 900 hole spinneret, with round holes 0.015 inches in diameter and
• Fiber A was then oriented by running over a set of feed rools at 29.3 ypm, followed by a set of draw rolls at 80.0 ypm, and delivered to a conveyer by puller rolls
• Fiber N was produced in a similar manner to Fiber
• Both types were cut to form water-dispersible fiber of 1/4, 3/8, 1/2 and 3/4 inch cut lengths and were ... tested on an inclined wire Fourdrinier machine. Fibers we ' re dispersed for three minutes in a small pulper at 0.75% consistency (lbs. fiber per 100 lbs. slurry, or furnish). The cylindrical pulper was approximately 3 feet in diameter by 6 feet deep. Fibers were then mixed with unrefined sulphite pulp to form a 50% polyester blend and diluted to 0.1% consistency in a 10 cubic meter stock tank. This stock was further diluted in the headbox of the machine to 0.0143% consistency and formed into a 0.5 meter wide wet lay nonwoven fabric at 20 meters/minute. A spray of an acrylic binder, Acronyl 240D was spray applied at the end of the Fourdrinier wire. The fabric was then cured in a through air drier at 150 ⁇ C. Finished fabric weight averaged 40 grams/square meter.
• Dispersion quality can be judged by the uniformity of the fabric produced from a given sample. As cut length increases, the uniformity of the fabric can generally be expected to suffer significantly. However, great advantages can result from using a longer fiber because the fabric tear strength increases, for example. In practice, therefore, a fabric producer will generally wish to use the longest fiber that will meet his uniformity standards. Thus, a longer fiber with improved, or equivalent uniformity would be preferred.
• Fiber N had the following average properties: Air Permeability, Gurley 112%
• Item N On balance. Item N exhibited advantages in the important areas of higher permeability, opacity, bulk and tear strength compared to the control at equivalent tensile strength with a small reduction in stretch. The cover advantage is important because less fiber can be used for a nonwoven fabric with similar performance characteristics, thereby saving materials cost. The fabrics of Item N also have an attractive flannel-like hand.
• the cruciform cross-section fiber of the invention When used with the appropriate water-dispersible coating in appropriate amount, the cruciform cross-section fiber of the invention has given a fabric with surprisingly good dispersion uniformity, and the properties indicated.
• Undispersed surface area The undispersed fiber exists in logs or clumps of many hundreds of fibers, most of which are on the inside of the logs. Therefore the undispersed surface area is negligible compared to the dispersed area, and the energy term can be expressed approximately as: Energy - (Surface Tension) X (Number of fibers) X

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Polyesters Or Polycarbonates (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=24897603

Family Applications (1)

Country Status (11)

Cited By (1)

Families Citing this family (5)

Citations (6)

Family Cites Families (12)

• 1986
  • 1986-04-08 CA CA000506113A patent/CA1280266C/en not_active Expired - Lifetime
  • 1986-04-08 IE IE905/86A patent/IE57359B1/en unknown
  • 1986-04-08 JP JP61502273A patent/JPS62502484A/ja active Granted
  • 1986-04-08 WO PCT/US1986/000685 patent/WO1986006112A1/en active IP Right Grant
  • 1986-04-08 KR KR1019860700877A patent/KR880002441B1/ko not_active IP Right Cessation
  • 1986-04-09 ES ES553822A patent/ES8800998A1/es not_active Expired
  • 1986-04-09 DE DE8686104816T patent/DE3664503D1/de not_active Expired
  • 1986-04-09 AT AT86104816T patent/ATE44787T1/de active
  • 1986-04-09 CN CN86102459.1A patent/CN1005734B/zh not_active Expired
  • 1986-04-09 EP EP86104816A patent/EP0198401B1/de not_active Expired
  • 1986-11-18 FI FI864687A patent/FI80078C/fi not_active IP Right Cessation

Patent Citations (6)

Also Published As

Similar Documents

Legal Events