Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-06-30
2001-07-17
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S165000, C525S178000, C525S200000, C524S319000, C524S462000, C428S221000, C428S411100
Reexamination Certificate
active
06262180
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to fiber, film and molded article compositions comprising hydrophobic and oleophobic synthetic organic polymer. In another aspect, the present invention relates to methods for preparing hydrophobic and oleophobic fiber, film and molded articles from synthetic organic polymer. In yet another aspect, the present invention relates to fabrics comprising hydrophobic and oleophobic synthetic organic fiber and to methods of making such fabrics.
BACKGROUND OF THE INVENTION
Synthetic organic polymers, especially polyolefins, are employed widely to create a variety of products. Included among such varied products are: blown and cascade films, extruded sheets, foams, fibers, products made from foam and fibers, woven and knitted fabrics, non-woven fibrous webs and molded articles. Many polymers used in these products, such as polypropylene, exhibit some hydrophobicity (i.e., water resistance), but exhibit no oleophobicity (i.e., oil resistance).
The use of various fluorochemicals to treat topically a variety of fibers and fibrous substrates, such as textiles, carpet, leather, paper and non-woven webs, to impart to those materials desired properties not indigent to the virgin materials, is known. See, for example, Mason Hayek,
Waterproofing and Water/Oil Repellency,
24, Kirk-Othmer Encyclopedia of Chemical Technology, pp. 448-455 (3rd ed. 1979) or Banks, Ed.,
Organofluorine Chemicals and Their Industrial Applications,
Ellis Horwood Ltd., Chichester, England, pp. 226-234 (1979). Such fluorochemical compositions include fluorochemical urethane and urea-based oligomers as disclosed in U.S. Pat. No. 3,398,182 (Guenthner et al.), U.S. Pat. No. 4,001,305 (Dear et al.), U.S. Pat. No. 4,215,205 (Landucci), U.S. Pat. No. 4,606,737 (Stern), U.S. Pat. No. 4,668,406 (Chang), U.S. Pat. No. 4,792,354 (Matsuo et al.) and U.S. Pat. No. 5,410,073 (Kirchner); compositions of cationic and non-cationic fluorochemicals as disclosed in U.S. Pat. No. 4,566,981 (Howells); and compositions containing fluorochemical carboxylic acid and epoxidic cationic resin as disclosed in U.S. Pat. No. 4,426,466 (Schwartz). Also known are fluorochemical esters as disclosed by U.S. Pat. No. 3,923,715 (Dettre), U.S. Pat. No. 4,029,585 (Dettre), U.S. Pat. No. 4,264,484 (Patel); and, more specifically, fluorochemical esters derived from dimerized unsaturated fatty acids as disclosed by U.S. Pat. No. 4,539,006 (Langford) and World Published Application WO 93/10085 (Coppens et al.). These fluorochemicals can be applied to various fibrous substrates by methods known in the art, including spraying, padding, and finish bath immersion, or can be applied directly to the fiber before the fiber is woven by incorporating the fluorochemical into the fiber spin finish.
Blending fluorochemicals with synthetic organic polymers and melt extruding fibers from the molten blend to produce fibers and fibrous substrates exhibiting hydrophilicity and oleophilicity also is known. U.S. Pat. No. 5,025,052 (Crater et al.) describes fibers, films and molded articles prepared by melt extruding a blend or mixture of (a) fiber- or film-forming synthetic organic polymers and (b) fluorochemical oxazolidinones to produce fibers, films and molded articles having low surface energy, repellency to oil and water, and resistance to soils. U.S. Pat.
No. 5,380,778 (Buckanin) describes fibers, films, and shaped articles made by melt extruding a blend of a fluorochemical aminoalcohol and a thermoplastic polymer, such as polypropylene. U.S. Pat. No. 5,451,622 (Boardman et al.) describes shaped articles, such as fibers and films, made by melt extruding mixtures of fluorochemical piperazine compound and thermoplastic synthetic polymer. U.S. Pat. No. 5,411,576 (Jones et al.) describes an oily mist resistant electret filter media comprising melt blown electret microfibers and a melt processable fluorochemical having a melting point of at least about 25° C. and a molecular weight of about 500 to 2500, the fluorochemical preferably being a fluorochemical oxazolidinone, fluorochemical piperazine or a perfluorinated alkane having from 15 to 50 carbon atoms. U.S. Pat. No. 5,300,587 (Mascia et al.) describes oil-repellent polymeric compositions made by blending a perfluoropolyether and optionally a radical starter with a thermoplastic polymer, intimately mixing the resulting composition at high temperature for sufficient time to form macroradicals from the polymer, and cooling the final composition to room temperature. U.S. Pat. No. 5,336,717 (Rolando et al.) discloses fluorochemical graft copolymers derived from reacting monomers having terminal olefinic double bonds with fluorochemical olefins having fluoroaliphatic groups and polymerizable double bonds.
While these various fluorochemical melt additives can in some circumstances impart satisfactory hydrophobicity and/or oleophobicity to thermoplastic resins, they typically suffer poor thermal stability above 300° C., a melt processing temperature often encountered in the industry, and they also can be prohibitively expensive, lending self-evident limitation to their commercial utility.
SUMMARY OF THE INVENTION
Briefly, in one aspect, this invention describes hydrophobic and oleophobic fibers, fabrics, films and molded articles (including combinations thereof) comprising synthetic organic polymer wherein dispersed within the fiber, film, fabric or molded article and present at the surface of the fiber, fabric, film or molded article are fluorochemical compounds. The fluorochemical compounds so dispersed generally are those that can be depicted either by Formula I, Formula II, Formula III or Formula IV below:
[(R
f
)
n
—Q—O—C(O)]
p
—A (I)
[(R
f
)
n
—Q—C(O)—O]
p
—A′ (II)
[(R
f
)
n
—Q—N(R)—C(O)]
p
—A (III)
[(R
f
)
n
—Q—C(O)—N(R)]
p
—A′ (IV)
wherein:
R
f
is a fluorinated, preferably perfluorinated, alkyl group bonded through carbon;
n is 1 or 2;
Q is a divalent or trivalent linking group, where the divalent linking group can be simply a covalent bond;
p is 1, 2 or many, up to the valency of A or A′;
R is a hydrogen atom or is a substituted or unsubstituted alkyl group, preferably an alkyl group having from 1 to 6 carbon atoms;
A is the residue of a mono- or polyfunctional carboxylic acid; and
A′ is the residue of a mono- or polyfunctional alcohol or amine with the proviso that A or A′ contain at least 34, or alternatively at least 36, carbon atoms when Q is —CH
2
CH
2
—.
The above-depicted fluorochemicals and those compositions containing them impart hydrophobicity and oleophobicity to synthetic organic polymers when blended as melt additives with such polymers prior to their thermal extrusion. These fluorochemicals and fluorochemical compositions also offer the additional benefits of thermal stability above 300° C. and yield lower material cost compared to currently employed fluorochemical polymer additives.
In another aspect, the present invention relates to methods of preparing hydrophobic and oleophobic fibers, films, and molded articles from synthetic organic polymers containing the described fluorochemicals.
In yet another aspect, the present invention relates to fabrics comprising hydrophobic and oleophobic synthetic organic fiber, useful, for example, in medical fabrics and apparel, and filter media. Methods for making such fibers also is disclosed.
DETAILED DESCRIPTION OF THE INVENTION
Those fluorochemicals preferred in the practice of the invention are selected from the group of compounds that can be depicted generally by the formulas presented below:
[(R
f
)
n
—Q—O—C(O)]
p
—A (I)
[(R
f
)
n
—Q—C(O)—O]
p
—A′ (II)
[(R
f
)
n
—Q—N(R)—C(O)]
p
—A (III)
[(R
f
)
n
—Q—C(O)—N(R)]
p
—A′ (IV)
wherein:
R
f
is a fluorinated, preferably perfluorinated, alkyl group bonded through carbon that may be substituted or unsubstituted, cyclic or acyclic, linear or branched (or any combination
Gasper Alton J.
Klun Thomas P.
Temperante John A.
3M Innovative Properties Company
Burtis John A.
Hampton-Hightower P.
Weiss Lucy C.
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