Plastic and nonmetallic article shaping or treating: processes – With step of cooling to a temperature of zero degrees c. or...
Patent
1997-07-15
1999-03-09
Tentoni, Leo B.
Plastic and nonmetallic article shaping or treating: processes
With step of cooling to a temperature of zero degrees c. or...
264140, 264205, 264211, 2643282, 26433119, 528 61, 528 68, 528 76, 528 80, 528 85, 528481, 528906, C08G 1808, D01F 678
Patent
active
058795960
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
A cryogenic process for making polyurethaneureas is disclosed. Such polyurethaneureas are useful for making spandex and, ultimately, various types of clothing.
TECHNICAL BACKGROUND
Polyurethaneureas are used to make "spandex," herein defined as a manufactured fiber in which the fiber-forming substance is a long-chain synthetic polymer comprised of at least 85% of a segmented polyurethane. Spandex, in turn, is used to make many articles of commerce, especially various types of clothing, including swimsuits, hosiery, intimate apparel, outerwear and the like. Polyurethaneureas also find use in molded and extruded products. Polyurethanes may be blended with other materials before being spun, molded, and/or extruded into products.
Polymers used in making spandex are themselves usually made by forming a prepolymer between a polymeric diol and a diisocyanate, and then reacting the resulting prepolymer with a diamine in a solvent such as N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethylformamide (DMF). (The aforementioned prepolymer is sometimes referred to as a "capped glycol.") The resulting polymer chains may then be extended by further reaction with one or more chain extenders, typically diamines. The chains may subsequently be terminated by the addition of a chain terminator, e.g., a monoamine. This chain terminator can be mixed with the chain extender or can be added separately, after the chain extender.
From an economic standpoint, it would be desirable to prepare polyurethaneureas, suitable for use in spandex and other applications, in the substantial absence of solvent, and to be able to either melt spin, solution spin, or isolate such polymers for later spinning.
Processes for making and using polyurethaneureas are well known to those skilled in the art. See H. Mark, et al., Ed., Encyclopedia of Polymer Science and Engineering, Vol. 6 (3d ed. John Wiley & Sons, Inc., New York 1986) at pages 733-755, and Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 10 (4th ed. John Wiley & Sons, Inc., New York 1993) at pages 624-638.
U.S. Pat. No. 3,480,456 describes the grinding of a thermoplastic coating materials in blenders, attritors and hammer mills at temperatures to -50.degree. C. using dry ice (solid CO.sub.2). Japanese Patent Application Publication 55-30,008 discloses a process for the preparation of thermoplastic polyurethane powder while adding dry ice immediately before, simultaneously, or immediately after adding the chain-propagating agent.
SUMMARY OF THE INVENTION
This invention describes a process for making a polyurethaneurea composition comprising:
(a) cooling an isocyanate prepolymer or an equivalent thereof to a temperature that is the lesser of the T.sub.g of the isocyanate prepolymer and 100.degree. C.;
(b) forming a powder from said isocyanate prepolymer; chain extender and optionally one or more chain terminators; and
(d) warming said powder to at least about room temperature to produce a polyurethaneurea.
The present invention also includes a process for making a fiber, a film, and a molded and/or extruded product, which process includes the above steps. The present invention also includes products made by this process. Finally, the present invention includes a powder made according to the present process, which powder may be stored or transfered before being spun, extruded, molded, or otherwise processed into a fiber, film, or shaped product.
DETAILS OF THE INVENTION
For a process according to the present invention, a starting material can be formed from the reaction product of a polymeric diol with an isocyanate. The polymeric diol and isocyanate are sometimes referred to herein as reactive precursors. The reaction product, an isocyanate prepolymer (also known as a "capped glycol"), is then cooled to a temperature of about -100.degree. C. or less. Chain extenders such as diamines or glycols may be added to the mixture, which is subjected to grinding to produce a fine powder. Grinding can take place, however, at any time during this pr
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Translation of Japanese Patent Application Publication Kokoku 55-30,008 (Published Aug. 8, 1980).
H. Mark et al, Extrusion, Encyclopedia of Polymer Science and Engineering, 6, 571-631, 1986.
H. Mark et al, Plastics Processing, Encyclopedia of Polymer Science and Engineering, 11, 273-278, 1988.
H. Mark et al, Characterization of Polymers, Encyclopedia of Polymer Science and Engineering, 3, 299-300, 1985.
H. mark et al, Fibers, elastomeric, Encyclopedia of Polymer Science and Engineering,6, 733-755, 1986, 3rd Edition.
H. Mark et al, Elastomeric, Encyclopedia of Polymer Science and Engineering, 10, 624-638, 1993.
H. Mark et al., Fibers, Manufacture, Encyclopedia of Polymer Science and Engineering, 6, 802-839, 1986.
H. Mark et al, Blow Molding, Encyclopedia of Polymer Science and Engineering, 2, 447-448, 1985.
H, Mark et al, Coating Methods, Encyclopedia of Polymer Science and Engineering, 3, 563-565, 1985.
E. I. Du Pont de Nemours and Company
Tentoni Leo B.
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