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Publication numberUS3396071 A
Publication typeGrant
Publication dateAug 6, 1968
Filing dateMar 2, 1964
Priority dateMar 25, 1963
Publication numberUS 3396071 A, US 3396071A, US-A-3396071, US3396071 A, US3396071A
InventorsCouzens Peter John
Original AssigneeIci Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Non-woven polypropylene fabrics
US 3396071 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 3,396,071 NON-WOVEN POLYPROPYLENE FABRICS Peter John Couzens, Harrogate, England, assignor to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain No Drawing. Filed Mar. 2, 1964, Ser. No. 348,796 Claims priority, application Great Britain, Mar. 25, 1963, 11,698/ 63 3 Claims. (Cl. 161-150) This invention relates to non-woven products, in particular to non-woven paper-like fabrics composed of stereoregular polyolefine fibres.

It is known to produce felts and non-woven fabrics from artificial, in particular synthetic organic, fibres by processes involving preparation of a mat or batt of intermingled fibres and consolidation of this mat or batt in presence of a binding agent which may be a different fibre, a particulate solid or a solution or dispersion of the binder. It is also known to produce felt-like sheets from mixtures of oriented and unoriented polyester fibres, the latter acting as the binder fibres, as for example is described in British patent specifications 808,287 and 844,- 760. Such felt-like sheets, however, are not entirely satisfactory because heat treatment, which is usually part of the consolidation process, causes embrittlement of the unoriented polymer fibres leading to a reduced life of the product in use.

I have now found that non-woven paper-like fabrics can be produced without the use of dissimilar binding agents and without the disadvantages attendant upon embrittlement during the manufacturing process.

According to my invention I provide non-woven paper-like fabrics consisting wholly of stereoregular polyolefine fibres comprising at least by weight of undrawn stereoregular polyolefine fibres and up to 90% by weight of drawn stereoregular polyolefine fibres, said undrawn and drawn fibres having the same molecular structure.

The products of this invention are thin coherent sheets which may be transparent, translucent or opaque depending upon the processing conditions, i.e., the proportion of undrawn to drawn fibres used and the presence or absence of pacifiers therein. Paper-like fabrics are also sheet materials but these have a smooth, fibrous appearance.

By undrawn stereoregular polyolefine fibres I mean polyolefine fibres produced by melt or solution spinning of the polymer, not subjected to an additional cold drawing process and having a birefringence of less than 10- and an extension at break of more than 100%.

By drawn stereoregular polyolefine fibres I mean polyolefine fibres which have been oriented substantially fully and which have a birefringence above 10- an extension at break of less than 70% and a free shrinkage at 140 C. of at least 10%.

Any stereoregular olefine polymer which can be melt or solution spun into fibres, preferably having a denier per filament of less than 10, may be used to produce the non-woven products of this invention. For example linear polyethylene, isotactic or syndiotactic polymers of such olefines as propylene, isobutylene or 4-methyl-pentene-l and crystalline copolymers of olefines having a stereoregular structure, may be used to produce fibres suitable for use in the invention.

The non-woven paper-like fabrics of this invention are prepared by blending the undrawn and drawn fibres, for example by carding the cut fibres or by other mechanical means if uncut fibres are used, an appropriate mixture, which may contain polyolefine fibres of different chemical composition in the undrawn or drawn forms, of the drawn and undrawn fibres and hot compressing a mat or batt of the fibres either between the heated platens of a press or continuously by passage one or more times between the heated rollers of a calender. In either case for the production of satisfactory products the pressures should exceed 0.2 ton per square inch or 0.1 ton per inch width for the press and calender respectively. The surface temperature of the platens of the press or the heated bowl or bowls of the calender is dependent upon the polymer or polymers comprising the mat or batt but is suitably about l060 C. below the melting point of the lowest melting component.

I have found, surprisingly that the presence or absence or crimps in the polyolefine fibres used to produce the non-woven products of this invention is unimportant in that satisfactory products of high strength have been produced from fibres having little or no crimp. The prodnets of this invention will have pleasing aesthetic properties and good physical properties, in particular high tear and tensile strengths, find many outlets as for example as packaging materials, wall coverings, carpet tbackings, reinforcement for plastic articles, electrical insulation or apparel.

The following examples illustrate the invention but do not limit the scope thereof.

EXAMPLE 1 lsotactic polypropylene is melt spun through a 72-hole spinneret held at a temperature of 285 C. and the extruded filaments, wound up at 4,000 feet per minute, have the following properties:

Denier 5.7 Birefringence 19.3l l0 Tenacity, grams/denier 2.0 Extension at break, percent 330 Thickness (d), cm. 0.020

Weight (w), g. per sq. metre 133 Elmendorf tear strength kg. per cm. thickness (a) across the length of the sheet (T 1) (b) across the Width of the sheet (T 101 Tensile strength kg. per sq. cm. cross section (a) along the length (T 245 (b) along the width (T 77 A.S.T.M. Standard method D 1424-59.

Instron tensile tester using a specimen S 0.5 cm. and a breaking length of 5 cm.

The sheet is not embrittled by heating between glass plates at C. for 30 minutes.

EXAMPLE 2 Isotactic polypropylene is melt spun through a 72- hole spinneret at 268 C. and the extruded filaments, wound up at 520 feet per minute, have the following properties;

Denier 5.6 Birefrigence 1.8)(10 Tenacity 1.1 Extension 725 A batt of these fibres is prepared as in Example 1 from which a translucent sheet is prepared using one passage through a calender operated as in that example.

The product, a coherent translucent sheet through which print may be read easily has the following properties and is not embrittled by treatment for /2 hr. at 150 C.

EXAMPLE 3 Undrawn isotactic polyproplyene fibres of 1.52.5 inches length prepared as in Example 2 are mixed in equal proportions by weight with drawn isotactic polypropylene fibres of 1.5 inches length having the following properties;

Denier Birefringence 32.5 X Tenacit 7.2 Extension 5 1 Free shrinkage at 140 C. 38.2

The batt prepared by carding of the mixture is hotcalendered as in Example 1. A coherent sheet through which print may be read easily is produced having the following properties.

EXAMPLE 4 A translucent coherent sheet is produced as in Example 1 from a 1:9 by weight mixture of the undrawn polypropylene fibres of Example 2 with the drawn fibres of Example 3. The film has the following properties;

w 138 T 128 T 166 T1 104 '1" 65 EXAMPLE 5 A thin, paper-like fabric is produced from a batt prepared as in Example 1, but having a thickness of .04 inch, from a mixture of undrawn polypropylene fibres as used in Example 2 and drawn fibres as used in Example 3 containing 30% by weight of the undrawn fibres, by single-pass hot calendering (upper bowl surface tem- 4 perature C.) at a pressure of 0.1 ton per inch. The properties of the product are;

A transparent, coherent sheet is produced from a batt of polypropylene fibres as in Example 2 by pressing for one minute between the heated platens C.) of an hydraulic press at a pressure of 0.4 tons per sq. inch. The properties of the film are;

a 0.036 T51 89 T What I claim is:

1. Non-Woven fabrics consisting wholly of consoli dated, blended stereoregular polypropylene fibres comprising at least 10% by weight of undrawn fibres having a birefringence of less than 20x10 and an extension at break of more than 100% and being selected from the group consisting of melt spun stereoregular polypropylene fibres and solution spun stereoregular polypropylene fibres and up to 90% by weight of drawn, substantially fully oriented stereoregular polypropylene fibres having a briefringence above 25 10" an extension at break of less than 70% and a free shrinkage at 140 C. of at least 10%, said undrawn and drawn fibres having the same molecular structure and at least a proportion of the fibres having been bonded together at the fibre cross-over points as a result of the softening of the fibres thereat.

2. Non-woven fabrics according to claim 1 wholly comprising fibres of undrawn stereoregular polypropylene.

3. Non-Woven fabrics according to claim 1 wherein the fibres have a denier per filament of less than 10.

References Cited UNITED STATES PATENTS 3,186,893 6/1965 Mercer 161 3,112,300 11/1963 Natta et al. 26093.7 3,117,055 1/1964 Guandique et al 161-170 3,193,442 7/1965 Schmulz et. a1. l6l-169 3,229,008 1/1966 Harrington et al. 264122 FOREIGN PATENTS 808,287 2/1959 Great Britain. 844,760 8/ 1960 Great Britain.

ROBERT F. BURNETT, Primary Examiner.

L. M. CARLIN, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3112300 *Dec 9, 1957Nov 26, 1963Montedison SpaIsotactic polypropylene
US3117055 *Dec 15, 1959Jan 7, 1964Du PontNon-woven fabrica
US3186893 *Jun 8, 1961Jun 1, 1965Plastic Textile Access LtdLaminated materials including plastic netting
US3193442 *Dec 26, 1961Jul 6, 1965Ici LtdNon-woven products composed of nonuniformly drawn staple fibers
US3229008 *Dec 5, 1961Jan 11, 1966Eastman Kodak CoProcess for producing a polypropylene fibrous product bonded with polyethylene
GB808287A * Title not available
GB844760A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3484283 *Oct 26, 1967Dec 16, 1969Phillips Petroleum CoPlastic felt
US3502538 *Jun 14, 1968Mar 24, 1970Du PontBonded nonwoven sheets with a defined distribution of bond strengths
US3538565 *Jul 17, 1969Nov 10, 1970Phillips Petroleum CoSelective molecular orientation of fibers in plastic felt
US3546062 *Dec 9, 1969Dec 8, 1970Du PontUnbonded nonwoven web of polypropylene fibers
US3630816 *Jul 25, 1969Dec 28, 1971Chevron ResNonwoven sheets made from rectangular cross section monofilaments
US4574541 *May 31, 1984Mar 11, 1986Ewald Dorken Gmbh & Co. KgFoundation-drainage panel
US4668566 *Oct 7, 1985May 26, 1987Kimberly-Clark CorporationDisposable products; such as diapers
US4753834 *Apr 2, 1987Jun 28, 1988Kimberly-Clark CorporationNonwoven web with improved softness
US4778460 *Oct 7, 1985Oct 18, 1988Kimberly-Clark CorporationMultilayer nonwoven fabric
US4965122 *Sep 23, 1988Oct 23, 1990Kimberly-Clark CorporationReversibly necked material
US4981747 *Sep 23, 1988Jan 1, 1991Kimberly-Clark CorporationComposite elastic material including a reversibly necked material
US5320891 *Dec 31, 1992Jun 14, 1994Kimberly-Clark CorporationParticle barrier nonwoven material
US5492753 *Dec 8, 1993Feb 20, 1996Kimberly-Clark CorporationStretchable meltblown fabric with barrier properties
US5582903 *Nov 15, 1995Dec 10, 1996Kimberly-Clark CorporationProtective devices; disposable diaper, clothing
US5695868 *Nov 25, 1996Dec 9, 1997Kimberly-Clark Worldwide, Inc.Film formed of blend of polyolefin and filler and fibrous polyolefin nonwoven web bonded directly to film to form a laminate
US5855999 *Nov 25, 1996Jan 5, 1999Kimberly-Clark Worldwide, Inc.Breathable, cloth-like film/nonwoven composite
US6015764 *May 2, 1997Jan 18, 2000Kimberly-Clark Worldwide, Inc.Microporous elastomeric film/nonwoven breathable laminate and method for making the same
US6037281 *Dec 27, 1996Mar 14, 2000Kimberly-Clark Worldwide, Inc.A polyolefin polymer film laminated to nonwoven fabrics; use as sterilization wrap, surgical draping, surgical gowns, cover garments, protective clothing
US6111163 *Jun 26, 1997Aug 29, 2000Kimberly-Clark Worldwide, Inc.Breathable film comprising oriented microporous relaxed unbiased film layer comprising elastomer and filler having particle size that contributes to pore formation
EP0634505A1 Jul 6, 1994Jan 18, 1995Montell North America Inc.Improved propylene polymer yarn and articles made therefrom
Classifications
U.S. Classification442/401, 442/415, 442/411
International ClassificationD04H1/54, D04H1/544
Cooperative ClassificationD04H1/54, D04H1/544
European ClassificationD04H1/544, D04H1/54