Plastic and nonmetallic article shaping or treating: processes – With twining – plying – braiding – or textile fabric formation
Reexamination Certificate
2000-05-12
2002-07-30
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With twining, plying, braiding, or textile fabric formation
C264S130000, C264S211000, C264S211140
Reexamination Certificate
active
06426025
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to fiber production and fiber treatment that renders fiber soil resistant, oil repellent, and/or water repellent.
BACKGROUND OF THE INVENTION
In the formation of textile materials from extruded thermoplastic polymers, such as polypropylene, application of a spin oil to the filaments is standard practice. Spin finish including a spin oil is a lubricating composition deposited on the surface of the fiber to reduce the fiber-fiber friction and the friction developed as the yarn passes over the metal machinery surfaces. Spin oil typically contains a large number of chemical components, the major components being lubricant, antistatic agent and emulsifier. The amount of spin finish needed depends on the producer and manufacturing process, and typically the residual spin finish on the fiber varies between 0.7% and 5%. A major disadvantage of the use of a spin finish that includes a spin oil is that residues of the finish on the extruded fiber attract soil. It also decreases the efficiency of any protective treatment applied to the fiber and as such reduces the soil resistance of the finished products.
In the industrial production of textiles, such as carpet and apparel, it is common to treat such substrates with a composition to impart added desirable properties thereto, such as resistance to soiling by particulate or dry soil. Fluorochemical compositions are commercially used for this purpose. They can be applied to various substrates by methods which include, for example, spraying, foaming, padding, and finish bath immersion.
U.S. Pat. No. 4,264,484 discloses a liquid carpet treating composition containing a water-insoluble addition polymer that is derived from polymerizable ethylenically unsaturated monomer that is free of non-vinylic fluorine and has at least one major transition temperature higher than about 25° C., and a water-insoluble fluoroaliphatic radical- and aliphatic chlorine-containing ester having at least one major transition temperature higher than about 25° C.
U.S. Pat. No. 4,107,055 discloses a fabric coating composition, including a polymer having a glass transition temperature above room temperature, an ionic fluorinated surfactant and a carrier. The polymer is preferably applied to fabric at a rate giving a dry solids content of about 0.25 to 10%, to give dry soil resistance.
U.S. Pat. No. 4,043,964 discloses a coating which provides a durably soil-resistant carpet and which contains: (a) at least one phase of a specified, water-insoluble addition polymer derived from a polymerizable ethylenically unsaturated monomer that is free of non-vinylic fluorine, and (b) at least one phase of a specified, water-insoluble fluorinated component containing a fluoroaliphatic radical of at least 3 carbon atoms. The monomer from which the fluorinated component is formed may contain dicarboxylic acid, glycol, diamine, hydroxyamine, etc.
A common feature of the treating or coating compositions disclosed in the above-mentioned U.S. patents is that they are to be applied to the carpet or fabric after its production in a separate treating step. The application equipment and time required for such a treating step adds to the cost of the final product.
Textile fibers and yarns can also be treated by incorporation of a fluorochemical repellent treating agent in the spin finishing bath, for example, as disclosed in U.S. Pat. Nos. 4,190,545 and 4,192,754. A drawback of such a process is the formation of deposits on the rolls caused by sedimentation of the fluorochemical oil- and water-repellent agent/spin finish mixture. The deposit on the rolls can cause fiber breaks and must be removed frequently. This is time consuming and expensive and is no longer accepted as an application method by fiber manufacturers. Typically, the more spin finish added to the fluorochemical treating agent, the more roll build up occurs, and the greater the reduction in repellent properties of the finished product because of the high level of spin oil present on the treated substrate.
Alternatively, treated textile fibers and yarns can be obtained by melt extrusion of a blend of a synthetic fiber-forming polymer and a fluorochemical composition. Such melt extrusion is described for example in U.S. Pat. No. 3,839,312. This patent discloses that soil and stain repellency of extruded filaments of a synthetic resin can be improved by incorporating in the resin a small amount, about 1 percent, of an amphipathic compound having from one to four fluoroalkyl groups pendent from an organic radical. The repellency is provided by the fluoroalkyl groups, which tend to be concentrated at the surface of the fiber.
WO 92/18569 and WO 95/01396 disclose permanently soil resistant polymeric compositions such as fibers and yarns that have a fluorochemical dispersed throughout the polymer. These polymer compositions are prepared by melt extrusion of the fluorochemical with the desired polymer. Polymers that can be used with the fluorochemical include polyester, polypropylene, polyethylene and polyamide.
U.S. Pat. No. 5,025,052 discloses certain fluoroaliphatic group-containing oxazolidinone compositions. The patent also discloses fibers, films, and molded articles prepared, for example, by injection molding a blend or mixture of fiber-or film-forming synthetic organic polymers and certain fluorochemical oxazolidinones. The resulting fibers, films, and molded articles are said to have low surface energy, oil and water repellency, and anti-soiling properties.
European Pat. Pub. No. 0 516 271 discloses durably hydrophilic thermoplastic fibers comprising thermoplastic polymer and fluoroaliphatic group-containing non-ionic compounds.
While the above-mentioned publications, U.S. Pat. No. 3,839,312, WO 92/18569 and WO 95/01396, are successful in providing soil and stain repellency to a yarn or fiber and many currently used fluorochemical compositions have demonstrated utility in providing carpet with soil resistance, unfortunately a significant amount of the carpet or fabric manufactured cannot be treated to obtain the desired properties. The reason is that significant and varying amounts of spin oil often remain on the fiber or yarn, lowering the soiling resistance thereof or acting as contaminants which interfere with the fluorochemical treatment and diminish or prevent the desired result thereof.
WO 97/33019 discloses a carpet yarn that contains a hydrophilicity imparting compound dispersed in the filaments of thermoplastic polymer. Fluorochemical hydrophilicity imparting compounds are disclosed as preferred hydrophilicity imparting compounds. It is taught that as a result of the use of the hydrophilicity imparting compound in the filaments of the yarn, less or no spin oil is needed in the spin finishing bath and as a result, the carpet is less prone to soiling. Although this method is successful, the oil and/or water repellency properties of the obtained fibers is generally poor and there continues to be a desire to improve the soil repellency properties.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a process for obtaining a fiber comprising the steps of:
melt extruding a mixture of thermoplastic polymer and hydrophilicity imparting compound to form a plurality of filaments;
applying a spin finish to said filaments;
and spinning said filaments into a fiber;
wherein said spin finish comprises fluorochemical. In preferred embodiments, the fluorochemical is an effective oil and/or water repellent and it imparts good oil and water repellency properties to the fiber.
One advantage of the invention is that roll build-up does not occur on the fibers made according to the process even though the application of spin finishes comprising fluorochemical to thermoplastic fibers typically results in roll build-up. Also, the resulting fibers generally show good oil and water repellency properties and soil resistance. Additionally, low levels of spin oil can be employed on fibers made according to the invention without sacrificing their antistatic properties.
In another aspec
3M Innovative Properties Company
Tentoni Leo B.
Voortmans Gilbert
Weiss Lucy C.
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