US3821062A - Nonwoven polypropylene fabric - Google Patents

Nonwoven polypropylene fabric Download PDF

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Publication number
US3821062A
US3821062A US22676672A US3821062A US 3821062 A US3821062 A US 3821062A US 22676672 A US22676672 A US 22676672A US 3821062 A US3821062 A US 3821062A
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Prior art keywords
filaments
layer
sheet
percent
machine direction
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W Henderson
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Van Dorn Co
EIDP Inc
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EI Du Pont de Nemours and Co
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Priority to BE795453D priority Critical patent/BE795453A/xx
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US22676672 priority patent/US3821062A/en
Priority to CA163,443A priority patent/CA977925A/en
Priority to JP48017962A priority patent/JPS5920018B2/ja
Priority to NL7302153A priority patent/NL172573C/xx
Priority to IT2045473A priority patent/IT1006567B/it
Priority to FR7305312A priority patent/FR2172265B1/fr
Priority to LU67042A priority patent/LU67042A1/xx
Priority to GB776973A priority patent/GB1427040A/en
Priority to CH223973A priority patent/CH564117A5/xx
Priority to DE2307829A priority patent/DE2307829C2/de
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Publication of US3821062A publication Critical patent/US3821062A/en
Assigned to VAN DORN COMPANY reassignment VAN DORN COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: GALLAGHER, THOMAS A., KNOWLTON, PAUL, PATARINI, LEON
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
    • D04H3/02—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of forming fleeces or layers, e.g. reorientation of yarns or filaments
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B32B5/022—Non-woven fabric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B32B5/12—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer characterised by the relative arrangement of fibres or filaments of different layers, e.g. the fibres or filaments being parallel or perpendicular to each other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/02—Synthetic macromolecular fibres
    • B32B2262/0253—Polyolefin fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2471/00—Floor coverings
    • B32B2471/02—Carpets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24058—Structurally defined web or sheet [e.g., overall dimension, etc.] including grain, strips, or filamentary elements in respective layers or components in angular relation
    • Y10T428/24124—Fibers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/69—Autogenously bonded nonwoven fabric

Definitions

  • Nonwoven webs of directionally-laid polypropylene continuous filaments have been disclosed in Edwards U.S. Pat. No. 3,563,838.
  • the nonwoven webs of Edwards are useful for preparing carpets with high resistance to tearing in the machine direction, high resistance to stretch in the machine direction and a coincident high resistance to neckdown in the cross-direction when stressed in the lengthwise direction.
  • the specified directionality of the Edwards patent is responsible also for providing a high resistance to bias deformation.
  • Carpet backings of the Edwards type may be prepared and bonded by a number of methods. In Herrman U.S. Pat. No.
  • 3,546,062 a method is described for preparing sheets of randomly distributed filaments wherein the binder in the sheet is derived from segments in the filaments which are less highly drawn than other segments. These less drawn segments, being lower melting than the highly drawn segments, serve as bonding agents for the nonwoven web when the webs are heated. Herrman also discloses the use of mixtures of filaments wherein some of the filaments are highly drawn and other filaments are less drawn.
  • the purpose of the present invention is to provide a nonwoven polypropylene carpet backing which has a high level of unlatexed tufted tongue tear strength at reasonable levels of neckdown and which retains a high proportion of its tear resistance even after latexing.
  • the product of the invention is a length of layered nonwoven bonded continuous filament isotactic polypropylene fabric comprising a machine direction layer constituting from 40 to 60 percent of the fabric weight and so disposed as to provide. one surface of the fabric and a cross-machine direction layer which constitutes from 40 to 60 percent of the fabric weight, each of the said layers consisting essentially of binder fiber and matrix fiber, the latter having a denier/filament of at least 12 (averaged for the machine direction and crossmachine direction layers) and a tenacity of at least 2.5 gpd.
  • the said machine direction layer containing from 18 to 50 percent by weight of binder fiber and exhibiting an MD /XD value of at least 3.0 and said cross-machine direction layer containing from 18 to 50 percent by weight of binder fiber and exhibiting an XD /MD value of at least 3.0 wherein XD is a measure of the total filament length of each layer in the direction perpendicular to the fabric length direction, and MD is a measure of the total filament length of each layer in the fabric length direction, the filaments of the layered fabric being disposed in such a manner to provide the following directionality values for the layered fabric:
  • FIG. 1 is a schematic representation of a fabric of the MX type as described herein. The figure shows the sheet in the process of being deposited on a surface moving from right to left.
  • FIG. 2 is an apparatus arrangement as used for Examples I and II.
  • FIG. 3 is an apparatus arrangement as used in Example llI.
  • the product of the invention is a-bonded nonwoven fibrous sheet comprising two or more layers having a differing average directionality of filaments. It may be prepared following the general techniques described in Edwards U.S. Pat. No. 3,563,838 and as shown schematically in FIG. 5 of that patent, one layer, the lower layer, is composed primarily of filaments whose major directional component is along the machine direction of the sheet while another layer, the upper layer, is composed primarily of filaments whose major directional component is across the machine direction of the fabric length.
  • the relative lengths of fiber oriented in various directions in each layer is determined by use of the randometer technique described in said Edwards patent.
  • the layer of the sheet composed primarily of filaments whose major directional component is across the machine direction of the fabric length has been termed herein as the X layer while the layer whose major fiber directional component is in the machine direction of the fabric length has been termed the, M layer.
  • layer 2 is composed of fibers deposited with their major directional component in the machine direction and this layer is termed the M layer.
  • Layer 1 is composed of filaments whose major directional component is in the cross machine direction and this layer is termed the X layer.
  • the layers may be indicated by a sequence of letters indicating the order of laydown with the first letter indicating the bottom layer of the sheet and so forth.
  • XM indicates, for example, that the X layer is laid down first on a moving belt and the M layer is deposited on the X layer.
  • An MX-laid sheet has the machine layer deposited first and the X layer second.
  • a large number of jets may be used across the width of a collecting belt to deposit a single M layer or X layer.
  • several banks of jets may be used in succession. If successive banks of jets deposit filaments in the same general direction, then the collected material may be considered to be a single layer.
  • An MXM-laid sheet is prepared by successively depositing a machine direction layer, a cross-machine direction layer, andanother machine direction layer.
  • sufficient latex is applied to penetrate about one half the thickness of the backing.
  • the portion containing the latex be machine direction since this layer does not contribute appreciably to tear strength in the machine direction (which is most important to carpet manufacturers) and since the tear strength is reduced by application of latex.
  • the fibers laid in the crossmachine direction should be preserved so far as possible in their unlatexed condition.
  • the M layer should provide one surface of the fabric while the X layers should be present to the extent of at least 40 percent by weight and should be predominantly in that half of the fabric opposite the side that is latexed.
  • the bonded nonwoven sheet of the invention can be produced in low weights which are more economical than previous sheets and which nevertheless provide the carpet manufacturer with a carpet backing which can be tufted to produce carpets with high tufted tongue tear before or after latexing.
  • 3 oz./yd. sheets of the invention provide tufted carpets with an unlatexed tufted tongue tear of at least 55 lbs. at a neckdown of 1 percent and a latexed tufted tongue tear at about 50 percent penetration which is at least 70 percent of the unlatexed tufted tongue tear strength.
  • a ribbon of filaments 3 is obtained by extruding filaments 4 from spinneret 5, quenching the filaments and passing them over guides 6.
  • the ribbon of parallel filaments passes successively over rolls 7, 8, 9, 10, 11 and 12.
  • the yarn travels at increasingly greater speed at each successive roll.
  • a significant speed increase can occur between rolls 8 and 9 and usually between rolls 10 and 11 thereby providing an increase in molecular orientation (draw).
  • Drawing is assisted by heating the filaments or portions thereof at rolls 8 and 10. Since roll 8 is a smooth cylindrical roll, uniform drawing is obtained between rolls 8 and 9.
  • Roll 10 is a fluted roll and has grooves running along its surface in the axial direction.
  • the resulting filaments 13 have alternate highly oriented and less oriented segments along their length.
  • the filaments then pass to a slot jet 14 of the type shown in FIG. 6 of the Edwards patent.
  • the ribbon of filaments 13 passes around convex rolls 30 which widen the ribbon and then the filaments are electrostatically charged upon passing across the target bar of a corona charging device 15 such as that described in DiSabato, et al. U.S. Pat. No. 3,163,753.
  • the ribbon of electrostatically charged continuous filaments is sucked into the orifice of slot jet l4 and issues from the slot jet exit 17, to deposition on a belt 35 moving in the indicated direction.
  • the width of the descending ribbon is in the cross-machine direction.
  • a pulse of air is supplied at the jet exit alternately from one side of the moving ribbon of filaments and then from the other to deflect the ribbon and create a swath with filaments predominantly aligned in the machine direction.
  • the output from one or more additional spinnerets is handled in a similar manner but is deposited with alignment primarily in the cross-machine direction.
  • the ribbon of filaments 13 may be divided, with part of the filaments proceeding as previously-described and part passing over snub pins 19 over convex rolls 31 through corona charging means 32 and through slot 20 aligned at right angles to jet l4. Filaments 21 exiting slot jet 20 are alternately pulsed to provide a swath with filaments predominantly aligned in the cross-machine direction.
  • filaments 50 extruding from the spinneret 51 are divided into two streams.
  • the other group of filaments issuing from the spinneret pass around guide rolls 6] and 62 then over rolls 63 and 64 to roll 54 where they combine with the first group of filaments and continue as a single group.
  • a swath of filaments 77 predominantly aligned in the machine direction is deposited.
  • a similar arrangement of apparatus upstream with the slot jet at right angles to slot jet 59 is utilized to provide a layer with filaments 78 predominantly in the cross-machine direction.
  • the filaments are bonded by passage through saturated steam as described in Jung, U.S. Pat. No. 3,322,607 using a bonder of the type described in Wyeth, U.S. Pat. No. 3,313,002.
  • a finish is applied to avoid excessive fiber breakage during tufting.
  • the finish is preferably a polysiloxane as described in Jung U.S. Pat. No. 3,322,607. Excessive shrinkage is avoided by restraining the sheet through bonding.
  • the degree of bonding affects the properties of the nonwoven product. As bonding temperature increases the neckdown of the tufted substrate decreases to a minimum value. At the same time increasing bonding temperature causes the tufted tongue tear values to pass through a maximum value and then to decrease again. A balance of neckdown and tufted tongue tear properties is needed for carpet backing. Desirable products have 5 to 0.1 percent neckdown, the precise values varying with the intended use.
  • TEST METHODS Directionality In the examples, measurements are given for directionality of filaments in layers of the bonded sheet. These measurements are made in a manner similar to that described in Edwards U.S. Pat. No. 3,563,838 at column 9, lines 43-54. After the bonded sheet has been separated into X and M direction layers, the measurements are made optically on each layer by use of the randometer described in Edwards and the results averaged in proportion to the weight of the layers in the bonded sheet. For example, XD/45 is a measure of the total filament length in the bonded sheet in the crossmachine direction divided by the average of the total filament length in the bias direction.
  • MD/45 is a measure of the total filament length in the bonded sheet in the machine direction divided by the average of the total filament length in the bias direction. It should be understood that in these terms, 45 is not a divisor but is simply a symbol for filament length in the bias direction. Other details on the determination of the directionality factors including use of the randometer for the determination are found in the Edwards patent.
  • the measurements of XD and MD are determined for each layer. XD is a measure of the total filament length of a layer in the direction perpendicular to the fabric length direction and MD is a measure of the total filament length of a layer in the fabric length direction.
  • the machine direction tufted tongue tear strength of a tufted nonwoven fabric may be measured in the following manner: A bonded nonwoven MX fabric is lubricated with about 2 percent by weight of polymethylhydrogen siloxane. A sample of the lubricated sheet is cut along its length (in the machine direction) to form a strip 8 inches wide. The strip is mounted in a tufting machine so that the needles penetrate the sheet from the M-laid side, leaving tufts on the X-laid side of the sheet. The tufting machine has needles spaced 0.188 inch apart (3/ 16 gauge).
  • the fabric is tufted inthe ma chine direction over a width of 6 inches with a 3,700- denier crimped continuous filament yarn at 7 tufts/inch to provide a loop pile carpet with 0.438 inch pile height leaving 1 inch of untufted sheet on each side of the tufted portion.
  • the tufted substrate with 1 inch selvage on each side is cut to prepare samples8 inches (20.3 cm.) long (machine direction).
  • a machine direction cut is made in a prepared 8 inch X 8 inch sample starting at the center of one end and proceeding inthe machine (tufting) direction for 4 inches (10.2 cm.).
  • the sample is mounted in an lnstron tensile tester using 1.5 inch (3.8 cm.) by 2 inch (5.1 cm.) serrated clamps.
  • one side of the cut portion is mounted in the upper jaw and the other side of the cut portion is mounted in the lower jaw, giving a 180 change in direction for the sheet at the tear point.
  • the width of the sample is uniformly spaced between the jaws.
  • the full scale load is adjusted to a value greater than the tear strength expected for the sample.
  • Latexed Tongue Tear Latexed tongue tear is a measure of the ability of the finished carpet to withstand tearing forces after latexing.
  • a latex comprising three parts of Uniroyal 3912 latex (70.4 percent solids) and one part of Uniroyal 391 1 latex (71.0,percent solids) is prepared.
  • the 3912 product is an aqueous dispersion wherein the solid elas' tomeric particles are 60 weight percent styrene and 40 weight percent butadiene.
  • the 391 1 product is similar, but has 40 weight percent styrene and 60 weight percent butadiene in the solid elastorner particles.
  • An amount of the blended latex is applied to the back of the tufted carpet equivalent to about 10 times the weight of the carpet backing in the sample.
  • the latex is spread uniformly using rollers of different weight depending on the required level of latex penetration. Several samples are tested, the amount of latex penetration differing in each of the samples. The degree of penetra' tion is also dependent on the latex viscosity and the weight of the roller. After drying and curing at C.
  • the degree of penetration is determined on the various samples as follows: (1) Determine the weight (W,) of an unlatexed detufted, sample of area A, (2) In a latexed detufted sample of the same area deiaminate and remove all of the fibers that arenot penetrated (wetted) by latex anddetermine their weight W (3) The percent penetration P is determined by the formula P W W /W, X 100. A more approximate method for determining percent penetration is to delaminate the sample and observe the approximate depth of unpenetrated sheet material. Latexed samples prepared with varying amounts of latex are tongue tear tested by the same procedure as the unlatexed samples. The latexed tongue tear at 50 percent penetration is obtained by interpolation of the data for samples with several levels of percent penetration P.
  • Percent Neckdown Primary carpet backings for the manufacture of tufted carpets require resistance to width loss on stretching, coupled with high tear strength.
  • tufted primary carpet backings are subjected to considerable longitudinal stress which not only may lengthen the carpet in the machine direction, but also may cause a narrowing or necking down of the tuftedcarpet backing in the cross-machine direction.
  • Such dimensional changes are highly undesirable; unless corrected, they may cause changes in the carpet tufting pattern and may provide a tufted carpet of narrower width than is commercially acceptable.
  • the neckdown of the bonded and tufted nonwoven carpet backing may be measured in the following manner:
  • the bonded nonwoven fabric is tufted as for the tufted tongue tear tests and is out along tufting rows to provide a sample 5.5 inches (14.0 cm.) wide and 14 inches (35.6 cm.) long.
  • the sample is marked across its width direction with lines parallel to the end at 4.0 inches (10.2 cm.) and 8.0 inches (20.3 cm.) .from one end and 2.0 inches (5.1 cm.) from the other end.
  • Metal staples are fastened to the sheet across the 8.0 inch (20.3 cm.) line 0.197 inch (0.5 cm.) from each edge of the sample. The distance between the staples is measured to the nearest 0.01 inch (0.0254 cm.) and recorded.
  • the sample is mounted in an lnstron tensile tester with a clamp separation of 8 inches (20.3 cm.).
  • the sample is mounted in 1 inch (2.54 cm.) by 8 inch (20.3 cm.) lnstronclamps so that the clamps are touching the 4.0 inch and 2.0 inch lines on the sample and the sample is centered in the clamps.
  • the sample is then extended in the tester using a full scale load of 50 lbs. (22.7 kg). a crosshead speed of 10 inches (25.4 cm.) per minute and a chart speed of 20 inches (50.8
  • the Instron is set to stop when the load reaches 18 lbs. (8.2 kg.). This is equivalent to 3.3 lbs. per inch of sample width.
  • the distance between staples is measured to the nearest 0.0] inch (0.0254 cm.) while the sample is still under stress.
  • the percent neckdown is equal to the difference of the original distance between staples and the distance between staples while under stress divided by the original distance between staples and multiplied by 100.
  • Fiber Tenacity Matrix filaments are teased out of the bonded sheet, cut free, and mounted in the jaws of a tensile tester such as the lnstron. The sample is stretched at a rate of 2 in./min. between jaws 1 inch apart.
  • the breaking strength is defined as the load in grams at which the fiber breaks. Values are averaged for at least fibers. The breaking strength is converted into tenacity in grams/denier by dividing the average break strength by the average matrix denier per filament (see below). Binder Concentration and Matrix Fiber Denier The percentage of binder fiber or binder segments of segmented fibers is an important consideration. The binder fiber has not been drawn as much as the matrix fiber and thus has a lower orientation and melting point than the matrix fiber. The concentration of binder fiber can readily be controlled in the processes described above by varying the ratio of groove to surface area in the grooved roll or by increasing the proportion of filaments that avoid part or all of the draw rolls. In any case, the binder content of the bonded fabric can be readily predetermined by its process of manufacture.
  • binder fibers or segments of fibers have low degree of molecular orientation (low birefringence)
  • their color under crossed polarizing lenses differs from that of matrix fibers which have a high degree of molecular orientation and consequently identification based on color is possible.
  • the orientation difference is magnified in bonding where the high temperatures tend to destroy fine structure and reduce birefringence. This deorientation is largest when initial molecular orientation is low.
  • the molecular chains in the binder segments are significantly deoriented giving a grayish or yellowish-white fiber when viewed under crossed polarizing lenses and matrix fibers give intense coloration under the same conditions.
  • binder diameter is also larger than that of matrix so that fiber size may also be used as a binder identification feature.
  • birefringence can be measured to establish which fibers are binder and which are matrix.
  • percent binder a thin transverse section of measured basis weight is prepared and the length and diameter of all binder fibers within a known area of this section is measured using a projection microscope and polarized light. The diameters of the matrix fibers are also measured. From these measurements the percent binder by weight may be calculated using fiber density and cylindrical geometry.
  • the bonded sheet is delaminated into its component M and X layers. ln thick sheets these layers must be further delaminated to make all fibers visible. For good visibility the lamina should each be less than about 2 o7./yd. in basis weight. Production of thin sections using a microtome may also be acceptable. The weight per square area of the component M and X layers is determined. Then the specimens are mounted on a microscope slide and immersed in an oil of about 1.5 refractive index.
  • An image of the specimen is thrown onto a screen by use of a Projectina or similar microscope using polarized light passing through the sample and using about 60X magnification.
  • a tracing is made of binder segments by using a transparent overlay with Polarizing and analyzing filters set at to one another. The Filters are then rotated simultaneously in 20-25 steps until total rotation is 90. At each step any additional binder segment within the field of view is traced.
  • a new field of view is now chosen and the procedure repeated until a suitable total area has been scanned.
  • a map reader can now be used to measure binder length. This length divided by magnification gives actual length of binder in the area scanned.
  • a calibrated eyepiece can be readily used to measure diameters of the binder filaments between bonded sites where deformation is at a minimum.
  • the diameter of the matrix filaments can be measured in the same way. The measurements are, of course, corrected by the magnification factor.
  • the percent binder Q by weight in a given layer of sheet is calculated from Formula I:
  • Formula ll may be simplified to Formula II! by inserting the proper value for 1r and assuming density of 0.9 g/cm. for polypropylene:
  • EXAMPLE l Several nonwoven webs consisting of continuous filaments of isotactic polypropylene were prepared from a polymer having a melt flow rate of 3.2 using an arrangement similar to that shown in FIG. of Edwards U.S. Pat. No. 3,563,838 except that a row of three jets were used for cross-machine direction deflection on the upstream end of the belt and a row of three jets were used for machine direction deflection on the downstream end of the belt. The distance between jets and their elevation above the collecting surface were such that the output from adjacent jets did not overlap significantly but just barely met on the collecting surface.
  • the polypropylene filaments were extruded from six spinnerets at a temperature of 250C, the spinnerets each having 300 orifices of size 0.015 inch diameter at a throughput of 0.705 g/min/hole.
  • the bundle of filaments from each spinneret was formed into a ribbon of parallel filaments and each ribbon was segmentally drawn by passage successively over six rolls (each 24 inches circumference) arranged as in F10. 2, running at progressively higher speeds from roll '7 to roll 12.
  • the rolls 8 and 10 were steam heated to 130 and 140 respectively, while the other rolls were unheated.
  • the surface of roll 10 was grooved in the axial direction so that filaments were unheated over short lengths of the circumference.
  • the remaining portions of the circumference provided heat to draw those portions of the filament which passed over the heated surface.
  • the ribbon of segmentally drawn continuous filaments 113 thus formed was given a negative electrostatic charge by passage across the target bar of the corona charging device.
  • Each ribbon of the charged continuous filaments passed then to a single slot jet of the type described in FIG. 6 of Edwards.
  • the mainstream gap designated d in Edwards was 0.115 inch in width and 9.5 inches in the other dimension.
  • the oscillating plenum air gap designated 6 in the jet described in Edwards was about 0.008 to 0.010 inch measured from one parallel side to the other. This permitted a high air velocity of the secondary air stream without an increase in air flow and hence a high degree of deflection without disrupting filament separation and uniformity of the web at laydown.
  • the air velocity was between 10 and 1.2 times the primary air velocity in the jet.
  • the nonwoven web deposited by the six jets was collected on a suction receiver.
  • Fiber directionality in the sheet was determined on each of the two (i.e., X and M) layers. Data for the various sheets have been summarized in Table 2. Latexed tongue tear was also determined at about 50% penetration. Matrix fiber denier, fiber break strength and percent binder for the X and M layers were measured on one of the bonded sheets for each set of operating conditions. It
  • EXAMPLE ill Three nonwoven webs consisting of continuous filaments of isotactic polypropylene were prepared from a polymer having a melt flow rate of 2.5 using the same 6-jet arrangement as in Example I but using only 3 spinnerets to supply the 6 jets. Polypropylene filaments were extruded at a temperature of 270C. through three spinnerets, each having 800 orifices of size 0.020 inch diameter at a throughput of 0.56 g/min/hole. The filaments were drawn over successive rolls as described in Example l but only roll 110, the fluted roll, was heated. The temperature of roll 110 is shown in Table 3 and the roll speeds are indicated.
  • the ribbon of fllaments from each spinneret was split evenly between an M- and an X-deflecting jet after passing roll 12. Three jets were used for cross-machine laydown on the upstream end of a moving belt and three jets were used for machine direction laydown nearer the downstream end of the moving belt. Before entering the corresponding jets each of the ribbons of continuous filaments was charged as in Example i.
  • the nonwoven webs were collected on a moving belt, the belt speed being adjusted to give a basis weight of about 3.0 ozlyd
  • the nonwoven webs were bonded in steam as in Example ll.
  • Three 33-inch wide webs of 3.0 oz/yd average basis weight were produced using the above process and operating under the conditions shown in Table 3. Fiber properties and average sheet characteristics are given in Table 4. Web 11 is within the scope of this invention. Webs 2 and 3 are not.
  • the sheet could consist of MIXM layering providing that one outside layer M layer is at least 40 percent by weight of the total sheet and provided that one X layer is at least 40 percent by weight.
  • a nonwoven web consisting of continuous filaments of isotactic polypropylene was prepared from a polymer having a melt flow rate of 3.2 using one jet for cross-machine direction deflection on the upstream end of the belt and one jetfor machine direction deflection on the downstream end of the belt.
  • the polypropylene filaments were extruded from two spinnerets at a temperature of 250C, the spinnerets each having 500 orifices of size 0.015 inch diameter at a throughput of 0.68 g/min/hole.
  • the bundle of filaments from each spinneret was divided into two ribbons of parallel filaments in the ratio of 31/69 binder/matrix. The filaments were forwarded and drawn over six rolls as shown in FIG. 3.
  • the apparatus provided uniform drawing rather than segmented drawing since no fluted roll was employed. To achieve a difference in orientation between binder filaments and. matrix filaments, 31 percent of the filaments from each spinneret were strung over guides so as to bypass the first two forward ing rollswhilethe remaining percent passed over all six rolls.
  • filaments were extruded from spinneret 51.
  • the filaments were separated into two ribbons 70 and 71 by means of guides 52 and 61.
  • the ribbon 71 representing 69 percent of the filaments passed over guide 62 and then passed over the six rolls 63, 64, 54, S5, 56 and 57.
  • This ribbon of filaments 71 was drawn on the six rolls to produce filaments with a high degree of molecular orientation. This orientation was effected in two stages, first between rolls 64 and 54 and second between rolls 55 and 56. The drawing conditions are described in greater detail in Table 5.
  • Rolls 64 and 55 are smooth rolls, each heated to 135C.
  • the filaments from spinneret SII representing 31 percent of the total filaments were passed over guides 52 and 53 thereby avoiding rolls 63 and 64. These filaments passed over rolls 54, 55, 56, and 57 and had a lower degree of molecular orientation than the filaments from ribbon 71.
  • the combined ribbon 72 of high molecularly oriented and less molecularly oriented filaments passed through an electrostatic charging device consisting of a rnultipointed electrode 73 and a grounded cylindrical:
  • the charged filaments then pass through jet 59 which was provided with a main air supply 75 and secondary air supplies 76.
  • the main air supply carried the ribbon of filaments toward the collecting surface 60.
  • the secondary air supplies 76 provided for oscillating steam 77 of filaments.
  • the filaments from the second spinneret were handled in a similar manner, however, these filaments passed through a jet which caused them to oscillate in the cross direction. These filaments 78 were deposited on the same belt upstream.
  • the resulting sheet had the XM configuration with 50 percent by weight in the X layer and 50 percent by weight in the M layer. Properties of the sheet are shown in Table 6.
  • Tables 2, 4 and 6 for Examples 1, II and III show that tufted tongue tear values of 55 to 79 lbs. at 1 percent neckdown can be obtained on XM-laid ,sheets on a 3 oz/yd basis by proper control of directionality, use of high percent binder in each layer, use of high denier in the matrix filaments and useof tenacity of at least 2.8 in the matrix filaments.
  • the data also show that the latexed sheets of the invention retain a @high percentage of their tufted tongue tear values .through latexing.
  • Gap at 4 is .I I5 X 9.5 inch.
  • Secondary air gap at 6 is .0l0 X 9.5 inches.
  • a length of layered nonwoven bonded continuous filament isotactic polypropylene fabric comprising a machine direction layer constituting from 40 to 60 percent of the fabric weight and so disposed as to provide one surface of the fabric and a cross-machine direction layer which constitutes from 40 to 60 percent of the fabric weight, each of the said layers consisting essentially of binder fiber and matrix fiber, the latter having an average denier per filament of at least 12 and a tenacity of at least 2.5 g./den., the said machine direction layer containing from 18 to 50 percent by weight of binder fiber and exhibiting an MD /XD value of at least 3.0 and said cross-machine direction layer con taining from 18 to 50 percent by weight of binder fiber and exhibiting an XD /MD value of at least 3.0 wherein XD is a measure of the total filament length of each layer in the direction perpendicular to the fabric length direction, and MD is a measure of the total filament length of each layer in the fabric length direction, the filaments of the layered
  • the fabric of claim 1 having a machine direction layer at one surface and a cross-machine direction layer at the other surface of the fabric.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Nonwoven Fabrics (AREA)
  • Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
  • Manufacturing Of Multi-Layer Textile Fabrics (AREA)
  • Laminated Bodies (AREA)
US22676672 1972-02-16 1972-02-16 Nonwoven polypropylene fabric Expired - Lifetime US3821062A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
BE795453D BE795453A (fr) 1972-02-16 Tissu non tisse a couches en polypropylene isotactique
US22676672 US3821062A (en) 1972-02-16 1972-02-16 Nonwoven polypropylene fabric
CA163,443A CA977925A (en) 1972-02-16 1973-02-09 Bonded nonwoven polypropylene fabric
NL7302153A NL172573C (nl) 1972-02-16 1973-02-15 Gebonden, niet geweven gelaagd produkt, gevormd uit continue elementairdraden.
IT2045473A IT1006567B (it) 1972-02-16 1973-02-15 Supporto primario non tessuto per tappeto
FR7305312A FR2172265B1 (it) 1972-02-16 1973-02-15
JP48017962A JPS5920018B2 (ja) 1972-02-16 1973-02-15 ポリプロピレン不織布
LU67042A LU67042A1 (it) 1972-02-16 1973-02-15
GB776973A GB1427040A (en) 1972-02-16 1973-02-16 Non-woven fabrics of polypropylene fibres
CH223973A CH564117A5 (it) 1972-02-16 1973-02-16
DE2307829A DE2307829C2 (de) 1972-02-16 1973-02-16 Mehrschichtiger, gebundener Endlosfadenvliesstoff

Applications Claiming Priority (1)

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US22676672 US3821062A (en) 1972-02-16 1972-02-16 Nonwoven polypropylene fabric

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US3821062A true US3821062A (en) 1974-06-28

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ID=22850316

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US22676672 Expired - Lifetime US3821062A (en) 1972-02-16 1972-02-16 Nonwoven polypropylene fabric

Country Status (11)

Country Link
US (1) US3821062A (it)
JP (1) JPS5920018B2 (it)
BE (1) BE795453A (it)
CA (1) CA977925A (it)
CH (1) CH564117A5 (it)
DE (1) DE2307829C2 (it)
FR (1) FR2172265B1 (it)
GB (1) GB1427040A (it)
IT (1) IT1006567B (it)
LU (1) LU67042A1 (it)
NL (1) NL172573C (it)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3991244A (en) * 1974-06-24 1976-11-09 E. I. Du Pont De Nemours And Company Nonwoven polypropylene fabric
US3993812A (en) * 1975-03-06 1976-11-23 E. I. Du Pont De Nemours And Company Unbonded fibrous non-woven sheet and articles made therefrom
US4086381A (en) * 1977-03-30 1978-04-25 E. I. Du Pont De Nemours And Company Nonwoven polypropylene fabric and process
US4996091A (en) * 1987-05-26 1991-02-26 Acumeter Laboratories, Inc. Product comprising substrate bearing continuous extruded fiber forming random crisscross pattern layer
US5124102A (en) * 1990-12-11 1992-06-23 E. I. Du Pont De Nemours And Company Fabric useful as a concrete form liner
US5135692A (en) * 1989-11-20 1992-08-04 E. I. Du Pont De Nemours And Company Form for patterned concrete
US5247730A (en) * 1991-10-25 1993-09-28 E. I. Du Pont De Nemours And Company Method for attaching and bidirectionally tensioning a porous fabric over a form support
US5256224A (en) * 1991-12-31 1993-10-26 E. I. Du Pont De Nemours And Company Process for making molded, tufted polyolefin carpet
US5302099A (en) * 1992-09-28 1994-04-12 E. I. Du Pont De Nemours And Company Laminated fabric useful as a concrete form liner
US20080153373A1 (en) * 2006-12-22 2008-06-26 Walter Randall Hall Abrasion resistant fire blocking fabric
US20130082414A1 (en) * 2002-03-15 2013-04-04 Fiberweb, Inc. Microporous Composite Sheet Material
WO2024189066A1 (fr) 2023-03-13 2024-09-19 Sterimed Sas Pochette de stérilisation comportant un non-tissé poreux

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2276414A1 (fr) * 1974-06-24 1976-01-23 Du Pont Etoffe non tissee liee de polypropylene et sa production
JPS52165998U (it) * 1976-06-10 1977-12-15
JPS6330810Y2 (it) * 1984-10-20 1988-08-17
JPS63128307U (it) * 1987-02-16 1988-08-22

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL138974B (nl) * 1964-08-17 1973-05-15 Du Pont Niet-geweven velvormig textielmateriaal.
CA923418A (en) * 1967-07-07 1973-03-27 V. Edwards Clifton Bonded nonwoven fabric
US3563838A (en) * 1968-07-09 1971-02-16 Du Pont Continuous filament nonwoven web
NL159734C (it) * 1970-03-26

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3991244A (en) * 1974-06-24 1976-11-09 E. I. Du Pont De Nemours And Company Nonwoven polypropylene fabric
US3993812A (en) * 1975-03-06 1976-11-23 E. I. Du Pont De Nemours And Company Unbonded fibrous non-woven sheet and articles made therefrom
US4086381A (en) * 1977-03-30 1978-04-25 E. I. Du Pont De Nemours And Company Nonwoven polypropylene fabric and process
US4996091A (en) * 1987-05-26 1991-02-26 Acumeter Laboratories, Inc. Product comprising substrate bearing continuous extruded fiber forming random crisscross pattern layer
US5135692A (en) * 1989-11-20 1992-08-04 E. I. Du Pont De Nemours And Company Form for patterned concrete
US5124102A (en) * 1990-12-11 1992-06-23 E. I. Du Pont De Nemours And Company Fabric useful as a concrete form liner
US5247730A (en) * 1991-10-25 1993-09-28 E. I. Du Pont De Nemours And Company Method for attaching and bidirectionally tensioning a porous fabric over a form support
US5256224A (en) * 1991-12-31 1993-10-26 E. I. Du Pont De Nemours And Company Process for making molded, tufted polyolefin carpet
US5283097A (en) * 1991-12-31 1994-02-01 E. I. Du Pont De Nemours And Company Process for making moldable, tufted polyolefin carpet
US5302099A (en) * 1992-09-28 1994-04-12 E. I. Du Pont De Nemours And Company Laminated fabric useful as a concrete form liner
US20130082414A1 (en) * 2002-03-15 2013-04-04 Fiberweb, Inc. Microporous Composite Sheet Material
US9790629B2 (en) * 2002-03-15 2017-10-17 Fiberweb, Llc Microporous composite sheet material
US20080153373A1 (en) * 2006-12-22 2008-06-26 Walter Randall Hall Abrasion resistant fire blocking fabric
WO2024189066A1 (fr) 2023-03-13 2024-09-19 Sterimed Sas Pochette de stérilisation comportant un non-tissé poreux
FR3146681A1 (fr) 2023-03-13 2024-09-20 Sterimed Sas Non tissé poreux utilisé pour la réalisation d’articles de stérilisation

Also Published As

Publication number Publication date
GB1427040A (en) 1976-03-03
NL7302153A (it) 1973-08-20
FR2172265A1 (it) 1973-09-28
IT1006567B (it) 1976-10-20
DE2307829C2 (de) 1986-10-30
LU67042A1 (it) 1973-08-31
CA977925A (en) 1975-11-18
BE795453A (fr) 1973-08-16
DE2307829A1 (de) 1973-08-23
JPS5920018B2 (ja) 1984-05-10
CH564117A5 (it) 1975-07-15
FR2172265B1 (it) 1977-02-04
NL172573C (nl) 1983-09-16
JPS4892658A (it) 1973-12-01

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