Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
2000-07-10
2003-03-11
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S447000, C427S393400, C528S033000, C528S044000
Reexamination Certificate
active
06531228
ABSTRACT:
The present invention relates to textile treatment compositions to impart oil and water repellency to textiles, methods of treating textiles and to the resulting treated textiles.
Various processes exist for the treatment of textiles to impart some water and/or oil repellency. For example, the use of various fluorochemical compositions for such purposes on fibers and fibrous substrates, is known. See, for example, Banks, Ed.,
Organofluorine Chemicals and Their Industrial Applications
, Ellis Horwood Ltd., Chichester, England, 1979, pp. 226-234. As the fluorochemicals are generally expensive, extenders are generally added to reduce the cost. Considerable effort has been put forth in finding suitable extenders for use with fluorochemicals to impart water and oil repellency to fibers.
U.S. Pat. No. 5,466,770 describes a fluorochemical oil- and water-repelling agent together with a polymer extender and a polymer extender having a saturated carbon-carbon backbone chain and at least one percent by weight, based on the weight of the extender, of interpolymerized units derived from ethylenically-unsaturated monomer containing at least one blocked or masked isocyanato group.
U.S. Pat. No. 3,849,521 (Kirimoto et al.) describes water- and oil-repellent compositions containing an oil- and water-repellent fluoroalkyl-containing polymer and an additive copolymer containing monomer units having the formula CR
1
R
2
═CR
3
COOR
4
, wherein R
1
, R
2
and R
3
represent hydrogen atoms or methyl groups, and R
4
represents a C
1-18
alkyl group; and monomer units having the formula CH
2
═CR
5
CONHCH
2
OH, wherein R
5
represents a hydrogen atom or a methyl group.
U.S. Pat. No. 4,834,764 (Deiner et al.) describes the use of certain blocked isocyanate compounds in combination with reactive perfluoroalkyl containing (co)polymers. Such compounds are said to improve the oil and water repellency and also make possible a reduction in the amount of fluoroalkyl-containing compounds.
World patent publication W092/17636 (Dams et al.) describes certain compositions comprising a fluorochemical agent, a copolymer extender, and a blocked isocyanate extender.
The present invention provides for a tailored reactive molecule suitable for a chemically bonded thin textile coating that provides water and oil repellency without significantly impacting the feel of the fabric.
In a first aspect, this invention relates to a liquid polyurethane-based composition which comprises a polyfunctional liquid polyurethane-containing adduct wherein the adduct contains as a first functional group at least one structo-terminal blocked isocyanate moiety per molecule, and at least one second structo-terminal functional group per molecule which is a repellent moiety, preferably a perfluoro or siloxane moiety, or a combination thereof.
In a second aspect, this invention relates to a process for preparing a polyfunctional liquid polyurethane-containing composition as mentioned above, by a solvent-free multi-step process which comprises reacting in a first step a polyisocyanate with a polyol to provide an isocyanate-terminated intermediate, in a second step reacting the isocyanate-terminated intermediate with a blocking agent to block at least one isocyanate moiety and in a subsequent step, reacting at least one isocyanate moiety with a repellent compound. In a preferred method for the preparation of the polyfunctional polyurethane:
a) the polyisocyanate comprises at least two isocyanate moieties per molecule with mutually different reactivities to the polyol;
b) the polyol is an organic substance having a molecular weight of from 60 to 20,000 and containing per molecule from two or more isocyanate-reactive functional groups selected from the group consisting of —OH, —SH, —COOH, —NHR where R is hydrogen or alkyl, or epoxy; and
c) the repellent compound is a molecule containing one isocyanate-reactive functional group selected from the group consisting of —OH, —SH, —COOH, —NHR where R is hydrogen or alkyl, or epoxy and further containing a second functional group which is not an isocyanate or an isocyanate-reactive moiety,
characterized in that:
i) the first step is conducted in essentially anhydrous conditions and in the absence of a urethane-promoting catalyst, the polyol is added at a controlled rate to the polyisocyanate such that the reaction temperature does not exceed 100° C. and the total amount of polyol added is less than a stoichiometric equivalent with respect to the polyisocyanate;
ii) for the second step, the blocking agent is added in a total amount of less than a stoichiometric equivalent with respect to the isocyanate content of the intermediate;
iii) and in one or more subsequent steps, a repellent compound is added such that the final polymer is substantially free of any isocyanate functionality or any isocyanate-reactive functionality.
In another aspect, the invention is to a process for preparation of a polyfunctional polyurethane as above where steps (ii) and (iii) are reversed. Thus in step (ii), a repellent compound is added at less than a stoichiometric equivalent with respect to the isocyanate content of the intermediate and in step (iii), the blocking agent is added.
In yet another aspect, this invention relates to a process for imparting water and oil repellent properties to a textile comprising applying to a surface of a textile an amount of the above disclosed composition sufficient to impart water and/or oil repellent properties thereto. Such treated fibers are preferably heated in a second step at a temperature and for a time sufficient to cure the treated substrate.
This invention also relates to a repellant textile resulting from the treatment of such textile by the above described method.
Treatment of fibers by the composition and method of the present invention is advantageous in that the fiber retains the touch, feeling, color shade and softness originally possessed by the fibers even after treatment and imparts a water and/or oil repellency to such fibers.
A further advantage of the compositions of the present invention for treating textiles is that the urethane compositions have self-emulsifyable behavior and due to the nature of the compounds, their architecture can be tailored to result in smaller r emulsion particles. This imparts the advantage of applying a thinner coating of the above composition versus conventional water repellency compounds.
An additional advantage of the present invention is when the repellent moiety is a perfluoropolyether, such compounds allow self-organization to take place at room temperature so that the textile does not need to undergo a heat treatment after washing.
The polyfunctional polyurethanes of the present invention provide an additional advantage in that when applied to a textile, they are chemically bonded to the textile so that the water and/or oil repellency of such treated textiles is maintained by the textile after repeated washings or extensive use.
When used herein, the term “textile” refers to both textiles which are composed of natural fibers and/or synthetic fibers, for example wool, cotton, silk, nylon, cellulose and also blends of natural fibers and synthetic fibers, including synthetic fibers modified to react with an isocyanate functionality. The treated textile may be in the form of a fiber, a yarn, a woven fabric, a carpet, a knitted fabric, a nonwoven fabric which are formed from the fibers.
The term “repellent moiety” or “repellent compound”, or variations thereof, means a moiety or compound which when added to a textile will give the textile the characteristics of repelling water, oil or oil and water. Preferred repellent moieties are perfluorocarbons and siloxanes. Perfluorocarbons are generally characterized in imparting to a textile the ability to repel water and oil and siloxanes are characterized in imparting to a textile the ability to repel water. The ability to repel oils is also associated with stain resistance.
The composition of this invention is characterized in that it comprises a polyfunctional liquid polyurethane addu
Bartelink Camiel F.
Goetz Hans
Gruenbauer Henri J. M.
Moeller Martin
Dawson Robert
Dow Global Technologies Inc.
Feely Michael J
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