US3660868A - Manufacture of non-woven fibrous webs - Google Patents

Manufacture of non-woven fibrous webs Download PDF

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Publication number
US3660868A
US3660868A US825841A US3660868DA US3660868A US 3660868 A US3660868 A US 3660868A US 825841 A US825841 A US 825841A US 3660868D A US3660868D A US 3660868DA US 3660868 A US3660868 A US 3660868A
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Prior art keywords
depositing
devices
web
collecting means
traverse
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Expired - Lifetime
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US825841A
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English (en)
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Clive Harry Weightman
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Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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    • 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
    • D04H3/005—Synthetic yarns or filaments
    • D04H3/009—Condensation or reaction polymers
    • 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

Definitions

  • ABSTRACT A process for making a substantially uniform web comprising [30] Foreign Application Priority D traversing fiber or filament depositing means across a moving M 29 1968 G tB "25 7 conveyor under conditions defined by the formula 2. ⁇ ' 4 1968 ig; 2; ⁇ : ggigg (t+z) where y is the total effective width of web deposited by the fiber or filament depositing means measured in the [52] US. Cl ..l9/l63 direction of travel of the conveyor x is the speed of the 51 Int. Cl.
  • I is the turn round time of the r or filament deposit- ⁇ 58] Field of Search ..l9/l63, 155,156,156.3; means, is the traverse time 0f the fiber filament depositing means and n is any whole number.
  • the invention relates to methods of producing non-woven fibrous webs and in particular relates to methods of depositing fibers or filaments to form webs using a traversing technique.
  • Methods for forming fibrous webs by forwarding fibers or filaments from a supply source for example a hopper of staple fibers, a creel of bobbins or a filament spinning machine, and depositing them on a moving collecting surface are well known, the methods generally involving the use of rotating rolls or air streams to transport and deposit the fibers or filaments.
  • a supply source for example a hopper of staple fibers, a creel of bobbins or a filament spinning machine, and depositing them on a moving collecting surface
  • Such transporting and depositing devices have mainly been located in stationary positions opposite the moving collecting surface. ln order to obtain uniform webs having an overall width greater than that produced by a single depositing device, it has been necessary to arrange a numberof devices side-by-side, ensure each device deposits a uniform and similar array of fibers and filaments, position each device carefully and make use of complicated jointing techniques to ensure the correct degree of overlap.
  • the present invention in one of its aspects, comprises a method of forming a fibrous web on an advancing collecting surface which comprises traversing fiber or filament depositing means in a reciprocating manner across a collecting surface in directions transverse to the direction of movement of said collecting surface so that y 2m (1 z) where Y is the total effective widthof web deposited by the depositing means measured in the direction of travel of the collecting means, is the speed of the collecting surface, I is the turn-around time of the depositing means, 1 is the traverse time of the depositing means and n is any positive integer.
  • the turn round time, t may be constant or it may be a function of traverse time, z, depending on the design of the traverse mechanism.
  • the depositing devices may be traversed across the collecting surface by for instance mechanical, pneumatic or hydraulic means or by means of a linear induction motor, and the fact that any such traversing means takes a finite time to reverse its direction is one of the reasons for the inclusion of the term tin the formula relating to the method of the present invention.
  • the turn-round time t is the time elapsing from the moment when the depositing devices start to decelerate having travelled across the width of the collecting means to the moment when the depositing devices cease to accelerate when travelling in the opposite direction.
  • the depositing devices may continue to function during the turn round time but the web will be non-uniform and may be conveniently removed by edge trimming.
  • the only limitation concerning the type of traverse used is that it should travel substantially uniformly across the collecting surface.
  • y is taken as the effective width of the web deposited by that device measured in the direction of travel of the collecting means.
  • This effective width is dependent on the total width of web produced by the device and the distribution of fibers or filamentsin the web, which in turn depend on the type and design of the depositing device. lf the distribution is substantially uniform then the effective width is equal to the total width but if the distribution is non-uniform then the effective width is equal to some function of the total width depending upon the actual shape of the distribution.
  • the depositing devices may be pairs of nip rolls or baffle plates which generally produce an approximately rectangular distribution.
  • air ejectors are most useful.
  • Such air ejectors depending upon their design, may, when stationary, deposit circular, elliptical or rectangular shaped webs and for each type of ejector it is necessary to determine the distribution of filaments in the webs produced and then the effective widths. Rectangular shaped webs produced from rectangular slot-type ejectors are normally substantially uniform across their width and generally the effective width is substantially the same as the total width.
  • Circular and elliptical shaped webs however such as are produced from ejectors of say circular cross-section usually have a non-uniform distribution of filaments across their widths. Such distributions often approximate to Gaussian distributions and in this case the effective width should be taken as the Half-Peak Width.
  • the effective width, y of the single depositing device is found, the following procedure is adopted to calculate the conditions which will give a product having uniform thickness or weight per unit area.
  • the throughput of fibers or filaments through the depositing device will be known, as will the weight per unit area of product required.
  • the width of the product will also be known and depends on the length of traverse of the depositing device. From these fixed parameters the conveyor speed, .r, is readily calculated.
  • the values of y and .r are substituted in the equation representing the conditions for uniform weight per unit area, y 2xn (1+ 2) and the values of 2 (1+ z), the traverse cycle time, are found for n l, 2, 3, etc.
  • n I all parts of the conveyor surface will be covered twice, and if n 3 all parts of the conveyor surface will be covered six times by an individual web having a weight per unit area equal to one third of that deposited when n l.
  • n may be chosen to give a pattern of covers most suited to a particular end-use, but frequently only a limited number of choices of n will be available because of traverse machinery speed limitations.
  • a number of depositing devices can be used to increase throughput and preferably each individual depositing device gives a uniform cover by conforming to the equation y Znx (t z).
  • the use of more than one depositing device provides an opportunity for conveyor speed to be increased.
  • the resulting web will be composed of a number of superimposed uniform webs.
  • the several depositing devices may conveniently be attached to a single traversing device aligned in a direction parallel to the direction of motion of the collecting surface. Since each device is individually producing uniform cover the spacing of the devices along the traversing device is not important provided that the depositing devices do not interfere with each other.
  • the devices are spaced apart within the group so that the total effective width Y of the group is the sum of the effective widths y y y etc. of the webs produced by each of the devices working in conjunction.
  • the individual depositing devices forming the group may be grouped directly adjacent to each other and traversed together at spacing depending upon their effective widths y y y etc., or may be spaced apart along the length of the collecting surface and traversed together or oppositely depending on their spacing. This latter spacing will again be critically dependant on the effective widths y y y etc., of the webs produced by the several depositing devices and will be such as to eventually build up a continuous total effective width Y.
  • the throughput of the process can be still further increased by having a plurality of groups of depositing devices, each group producing a uniform web.
  • each device should preferably give uniform cover.
  • each device should preferably give uniform cover.
  • the means of achieving such a uniformity of product during involuntary failures of a number of depositing devices is an important aspect of the invention, and is now described.
  • each group containing p depositing devices and each group individually producing a uniform web and having an effective width, Y. Then each group must be obeying the relationship y 2nx (I z).
  • the conveyor speed, x has been chosen to give a product having a desired weight per unit area with all q-p depositing devices functioning. Now supposing that in one group, 5 depositing devices fail. Since it is the group as a whole which produces a uniform cover it will be necessary to deliberately fail the remaining (p 5) devices in that group in order to be able to regain the uniform product. Hence on failure of any 5 devices in a group, the number of devices lost due to inadvertant and deliberate failure will be p. If the 5 devices are not all in the same group it will be necessary to fail rp. devices where r is the number ofgroups affected.
  • (z t) can be altered by altering (i) the traverse time, z, (ii) the turn round time, t and (iii) both traverse time and turn round time. In case (i) z is altered to z* and in case (iii). (2+!) is altered to (z+l)* Should it be desired to retain the term, (2 +1), at a constant value, then it is necessary, in addition to reducing the con- VeyOI speed to to reduce the effective width to to maintain uniformity of web weight per unit area.
  • the method of production of a uniform web before and after failure of a number of depositing devices may conveniently be automated by use of failure detecting devices and automatic switching to change the collecting speed, x, and the speed of traverse of the depositing devices in a conventional manner.
  • n chosen will depend upon the weight required for the final web, the coherency desired in the final web, magnitude desired for the throughput from each depositing device, the traverse speed and the conveyor speed and is generally chosen to give the best compromise between these factors.
  • the collecting surface itself may conveniently be a foraminous conveyor belt but the actual nature of the belt will depend on the nature of the depositing devices used and may be a drum or flat imperforated surface.
  • FIG. 1 shows an end view of a continuous filament web depositing apparatus
  • FIG. 2 shows a section taken along the line A A ofFIG. 1;
  • FIGS. 3 6 show diagrammatically the construction of webs formed by a single fiber or filament depositing device giving uniform cover in different modes of operation according to the invention
  • FIG. 7 shows diagrammatically the construction of a web formed by two fiber or filament depositing devices having differing effective widths acting in conjunction to produce a uniform web
  • FIG. 8 shows diagrammatically the construction of a nonuniform web produced by the failure of one of the depositing devices used to produce the web ofFIG. 7.
  • FIGS. 1 and 2 show views of apparatus in which two rectangular air ejectors are traversed together.
  • the apparatus consists of a pair of forwarding rolls 10 mounted in tandem and a pair of smaller rolls 11 forming nips with the rolls 10, two air ejectors 12 spaced apart a specified distance affixed to a mounting block 13 by angle iron 14 and having mounted thereon banding devices 15, a runner bar 16, along which the mounting block 13 slides, supported by frameworks 17 and 18, a driving chain 19 affixed to the mounting block 13 and supported at its ends by sprocket means (not shown) mounted in frameworks 17 and 18, the sprocket means being driven via electromagnetic clutches by driving motors (not shown) mounted in frameworks 17 and 18 so that the mounting block 13 is traversed back and forth along the runner bar 16, and a foraminous conveyor belt 20 situated between frameworks 17 and 18 so that it travels in a direction at right angles to that of the mounting block.
  • the ejectors 12 are
  • the apparatus may include a plurality of depositing means disposed along the length of conveyor belt 20 as illustrated in FIG. 2 wherein primed reference numerals designate a second group of depositing elements.
  • FIGS. 3 to 6 show diagrammatic plan view of webs formed by a single fiber or filament depositing device giving uniform cover in different modes of operation according to the invention.
  • FIG. 3 shows the pattern of web produced with n l
  • FIGS. 4, 5 and 6 show the patterns with n 2, 3 and 4 respectively.
  • the effective width of web deposited is the same and is indicated by the distance between points 26 and 27.
  • Points 28 and 29 indicate the position of web deposition after a single traverse of the depositing device across the collecting surface from the position indicated by points 26 and 27, assuming that the collecting surface is moving from right to left in the figures.
  • the effect of a finite turn round time for the traversing depositing devices is shown by the gap between points 30 and 31 on the web.
  • Lines 32 in FIGS. 3 6 indicate widths of web deposited in any traverse and the number of lines 32 crossing any particular portion of the web indicates the number of covers constituting that portion of the web. It is seen that between initial and final traverses the webs produced are uniform, having a number of covers equal to Zn. Other depositing devices may be used also operating in according to the invention to superimpose their uniform webs on the uniform base web and may be spaced at any points above the collecting surface.
  • FIG. 7 shows a diagrammatic plan view of a web produced by two depositing devices, one having an effective width equal to twice the other, co-operating to produce a uniform web. For convenience the effect of a finite turn round time has been ignored. Points 36 and 37 indicate the effective width of web deposited by one depositing device and points 38 and 39 indicate the effective width deposited by the second device. The devices are so positioned that they produce a combined effective width equal to the distance between points 36 and 40.
  • the devices may be traversed together and arranged sideby-side so that they deposit webs between points 36 and 37 and 37 and 40, may be traversed together and spaced apart defined distances so that, for instance, one device deposits web between points 36 and 37 and the other device deposits web between points 38 and 39 or may be traversed oppositely to one another so that, for instance, one device deposits web between points 36 and 37 and the other device deposits web between points 43 and 44 or, say,4l and 42.
  • FIG. 8 shows the web produced by the depositing devices employed to manufacture the uniform web of FIG. 7 with the device having the smaller effective width failed.
  • the resulting web is non-uniform having areas 45, 46, 47 in which there is double cover, areas 48, 49, 50 in which there is single cover and uncovered areas 51, 52 and 53.
  • EXAMPLE Eight air ejector depositing devices having substantially similar effective widths were attached to a common mounting which was traversed above an endless conveyor advancing perpendicularly to the direction of traverse of the depositing devices.
  • the air ejectors were found to give an elliptical distribution of deposited filaments and the effective width of the devices was found to be 25 29 cm.
  • the conveyor was arranged to advance 27 cm. in each complete traverse cycle.
  • Continuous filaments of polyhexamethylene adipamide were fed to all of the devices and the throughput was such that a product having a nominal weight of 6 oz./yd. (about 210 g.m. was obtained.
  • Each device thus obeyed the relationship y 2x (t z), i.e. gave individually substantially uniform cover as shown diagrammatically in FIG. 3 of the accompanying drawings.
  • Samples of the web measuring 20 X 20 cm. were cut at intervals from the web and their weights measured.
  • the mean weight of twelve 400 cm. samples was 8.27 g. and the standard deviation was 0.44.
  • the value of standard deviation was due to the varying effective widths of the depositing devices. When two devices having the same effective width of 27 cm. were used to make a nominal 6 oz./yd. (2l0 g./m. web the mean weight of 12 samples measuring 20 X 20 cm. was found to be 8.15 g. and the standard deviation was 0.08.
  • a method of forming a fibrous web having at least a substantially uniform weight per unit area which comprises traversing a plurality of depositing devices in a reciprocating manner above a continuously advancing collecting means in directions perpendicular to the direction of advance of said collecting means and depositing thereon a web of fibers or filaments such that y 2nx (t z) where y is the effective width (as herein before defined) of said web deposited by said depositing means measured in the direction of travel of said collecting means; at is the speed at which said collecting means advances; z is the traverse time of said depositing means; t is the turn around time of said depositing means and n is any positive integer and further including reducing said speed of said collecting means, .r,on failure of one or more said depositing devices by the fraction obtained by dividing the number of said failed depositing devices by the total number of said devices and simultaneously increasing the total traverse cycle time by the reciprocal of the said fraction.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nonwoven Fabrics (AREA)
  • Paper (AREA)
  • Preliminary Treatment Of Fibers (AREA)
US825841A 1968-05-29 1969-05-19 Manufacture of non-woven fibrous webs Expired - Lifetime US3660868A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2577668 1968-05-29
GB4722368 1968-10-04

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US3660868A true US3660868A (en) 1972-05-09

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US (1) US3660868A (enrdf_load_stackoverflow)
BE (1) BE733806A (enrdf_load_stackoverflow)
DE (1) DE1926951C3 (enrdf_load_stackoverflow)
FR (1) FR2009616A1 (enrdf_load_stackoverflow)
GB (1) GB1231066A (enrdf_load_stackoverflow)
NL (1) NL6908140A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2525819A1 (de) * 1974-06-10 1976-01-02 Rhone Poulenc Textile Vrfahren zum herstellen von vliesen aus endlosgarnen und vorrichtung zum durchfuehren des verfahrens
US5454145A (en) * 1991-06-28 1995-10-03 Asselin (Societe Anonyme) Method for manufacturing a nonwoven product, a nonwoven product obtained in particular by said method and an installation for the manufacture of said nonwoven product
US20080102145A1 (en) * 2005-09-26 2008-05-01 Kim Hak-Yong Conjugate Electrospinning Devices, Conjugate Nonwoven and Filament Comprising Nanofibers Prepared by Using the Same
US20080233284A1 (en) * 2004-03-23 2008-09-25 Kim Hak-Yong Bottom-Up Electrospinning Devices, and Nanofibers Prepared by Using the Same
US20090189318A1 (en) * 2004-01-30 2009-07-30 Kim Hak-Yong Bottom-up electrospinning devices, and nanofibers prepared by using the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4158557A (en) * 1978-04-26 1979-06-19 Ppg Industries, Inc. Method and apparatus for forming fiber mat

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3183557A (en) * 1961-12-20 1965-05-18 Du Pont Crosslapping method and apparatus
US3222730A (en) * 1961-11-13 1965-12-14 Johnson & Johnson Methods and apparatus for producing textile fabrics
US3394435A (en) * 1966-05-31 1968-07-30 Du Pont Apparatus for making a nonwoven web
US3460731A (en) * 1967-07-07 1969-08-12 Du Pont Filament deflecting apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3222730A (en) * 1961-11-13 1965-12-14 Johnson & Johnson Methods and apparatus for producing textile fabrics
US3183557A (en) * 1961-12-20 1965-05-18 Du Pont Crosslapping method and apparatus
US3394435A (en) * 1966-05-31 1968-07-30 Du Pont Apparatus for making a nonwoven web
US3460731A (en) * 1967-07-07 1969-08-12 Du Pont Filament deflecting apparatus

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2525819A1 (de) * 1974-06-10 1976-01-02 Rhone Poulenc Textile Vrfahren zum herstellen von vliesen aus endlosgarnen und vorrichtung zum durchfuehren des verfahrens
US4017580A (en) * 1974-06-10 1977-04-12 Rhone-Poulenc-Textile Process and apparatus for manufacturing non-woven webs of continuous thermoplastic filaments
US5454145A (en) * 1991-06-28 1995-10-03 Asselin (Societe Anonyme) Method for manufacturing a nonwoven product, a nonwoven product obtained in particular by said method and an installation for the manufacture of said nonwoven product
US20090189318A1 (en) * 2004-01-30 2009-07-30 Kim Hak-Yong Bottom-up electrospinning devices, and nanofibers prepared by using the same
US20080233284A1 (en) * 2004-03-23 2008-09-25 Kim Hak-Yong Bottom-Up Electrospinning Devices, and Nanofibers Prepared by Using the Same
US20080102145A1 (en) * 2005-09-26 2008-05-01 Kim Hak-Yong Conjugate Electrospinning Devices, Conjugate Nonwoven and Filament Comprising Nanofibers Prepared by Using the Same

Also Published As

Publication number Publication date
GB1231066A (enrdf_load_stackoverflow) 1971-05-05
DE1926951C3 (de) 1979-09-13
FR2009616A1 (enrdf_load_stackoverflow) 1970-02-06
BE733806A (enrdf_load_stackoverflow) 1969-12-01
DE1926951B2 (de) 1979-01-25
NL6908140A (enrdf_load_stackoverflow) 1969-12-02
DE1926951A1 (de) 1969-12-04

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