CA1045431A - Method of making biaxially oriented nonwoven fabrics - Google Patents
Method of making biaxially oriented nonwoven fabricsInfo
- Publication number
- CA1045431A CA1045431A CA261,563A CA261563A CA1045431A CA 1045431 A CA1045431 A CA 1045431A CA 261563 A CA261563 A CA 261563A CA 1045431 A CA1045431 A CA 1045431A
- Authority
- CA
- Canada
- Prior art keywords
- fibers
- fabric
- areas
- fiber density
- long
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/006—Making patterned paper
-
- 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
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
- D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
- D04H1/736—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged characterised by the apparatus for arranging fibres
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Nonwoven Fabrics (AREA)
- Paper (AREA)
- Treatment Of Fiber Materials (AREA)
Abstract
A B S T R A C T
A nonwoven fabric having alternating stripes of high fiber density and low fiber density has fibers of at least 1/2" in length and fibers of less than 1/2" in length, preferably under 1/4" in length. The fabric is made by papermaking techniques wherein a slurry of stock of the long and short fibers is prepared and delivered to a conventional papermaking machine. The stock flow of fibers then passes into a headbox, where the flow is stabilized. The stabilized stock flow then passes onto a moving fourdrinier screen having a set of finger-like striping bars positioned thereover, or a set of fluid-impervious resist areas disposed directly thereon. As the water-borne fibers pass onto the section of the screen having the resist areas thereon, a majority of the long fibers and substantially all of the short fibers therein are at least at first attracted to the spaces between the resist areas and are generally disposed in an orientation that follows the direction of the resist areas, while a lesser number of long fibers bridge across the resist areas and remain in a generally cross-direction to those resist areas after the thusly formed web of fibers moves entirely onto the moving four-drinier. The short fibers in the fabric may advantageously be paper fibers, cotton linters, thermoplastic fibers, or the like, thereby greatly enhancing some of the product characteristics while greatly reducing the cost of raw materials used therein. Some of the fibers in the fabric, as stated above, may be of a thermoplastic nature so that, when heated, they will provide a binder for the fabric.
A nonwoven fabric having alternating stripes of high fiber density and low fiber density has fibers of at least 1/2" in length and fibers of less than 1/2" in length, preferably under 1/4" in length. The fabric is made by papermaking techniques wherein a slurry of stock of the long and short fibers is prepared and delivered to a conventional papermaking machine. The stock flow of fibers then passes into a headbox, where the flow is stabilized. The stabilized stock flow then passes onto a moving fourdrinier screen having a set of finger-like striping bars positioned thereover, or a set of fluid-impervious resist areas disposed directly thereon. As the water-borne fibers pass onto the section of the screen having the resist areas thereon, a majority of the long fibers and substantially all of the short fibers therein are at least at first attracted to the spaces between the resist areas and are generally disposed in an orientation that follows the direction of the resist areas, while a lesser number of long fibers bridge across the resist areas and remain in a generally cross-direction to those resist areas after the thusly formed web of fibers moves entirely onto the moving four-drinier. The short fibers in the fabric may advantageously be paper fibers, cotton linters, thermoplastic fibers, or the like, thereby greatly enhancing some of the product characteristics while greatly reducing the cost of raw materials used therein. Some of the fibers in the fabric, as stated above, may be of a thermoplastic nature so that, when heated, they will provide a binder for the fabric.
Description
104543~
BACKGROUND OF THE INVENTION
This invention relates to biaxially oriented striped nonwoven fabrics and a method for making same, and more part-icularly, to a method of making a nonwoven fabric having al-ternating high fiber density and low fiber density striped portions, and fiber mixtures of both long and short fiber lengths, said fabric having substantially biaxial orientation of fibers throughout the fabric.
Nonwoven fabrics are now used for a variety of purposes in a number of industries. These fabrics have been made tradi-tionally by methods such as carding, garnetting, air-laying and the like. Nonwoven webs have been made to have most of the fibers therein oriented in the machine direction; other non-woven webs have been made to have some cross orientation; and still other webs have been produced having a randomized fiber distribution. However, sutstantially all of these webs are lacking in any surface character or natural decorative effect.
Nowhere in the art, heretofore, has a nonowoven fabric been made in an unlayered structure having a striped construction wherein half of the stripes have a high fiber density and the other half of the stripes are of low fiber density; further-more, no fabrics have yet been made in such a strip3d m~er, for example wherein a majority of the fibers in the high fiber density stripes are oriented in a direction parallel to stripes (machine direction~, while a majority of the fibers in the low fiber density stripes are oriented in a direction substantially perpendicular to the stripes (cross direction). No method has yet been devised for manufacturing such a fabric with at least two types of orientation disposed thereon simultaneously.
Furthermore, it has been discovered that while the bi-axially oriented nonwoven fabric described above has been very satisfactory in many respects, efforts have been undertaken to 104~43~
attempt to reduce the cost of raw materials therein, while increasing the bulk, softness, feel and look of the resulting nonwoven fabric. Thus, a papermaker's method for making this nonwoven, using short paper fibers, will reduce costs dramati-cally.
The invention provides a method of making biaxially oriented nonwoven fabrics having areas of low fiber density and high fiber density wherein a majority of the fibers in said low fiber density areas are oriented in a direction sub-stantially normal to the fibers in the directly adjacent highfiber density areas and a majority of the fibers in said high fiber density areas that lies directly adjacent said low fiber density areas are oriented in a direction substantially parallel with the contours of the configuration of the low fiber density area comprising: preparing a stock of blended long and short fibers, said long fibers being at least one-half inch in length or more and said short fibers being less than one-half inch in length; maintaining said stock of fibers in an agitated state;
causing a flow of said stock to pass into a headbox, and stabilizing same therein; passing said stabilized stock flow onto moving fourdrinier screen having fluid-impervious resist areas thereon; causing a majority of said long and said short fibers in said stock flow to locate outside said fluid-impervious resist areas, said majority of fibers that lie directly adja-cent said fluid-impervious resist areas orienting themselves in a direction substantially parallel with the contours of said resist areas; simultaneously causing a minority of said long and short fibers in said stock flow to locate across said fluid-impervious resist areas, said minority of said long and short fibers orienting themselves in a substantially cross direction normal to the axis of said fluid-imperious resist areas; secur-ing said biaxially oriented nonwoven fabric in said orientation B
as described herein; carrying said biaxially oriented nonwoven fabric on said moving fourdrinier screen toward a pick-up means fGr collecting the thusly formed fabric; and, collecting said fabric on said pick-up means. The nonwoven fabric with long and short fibers therein can have a striped patterned construction manufactured into it, which would be able to be produced with relatively inexpensive short fibered materials, The nonwoven fabric may have alternating stripes of high fiber density and low fiber density, wherein a majority of the fibers in the high fiber density stripes are oriented in the machine direction while a majority of the fibers in the low fiber density stripes are oriented in the cross direction. The direction of the stripes may run across the fabric or at some other angle that is bias to the angle of the direction of travel of the fabric.
By placing lines of fluid-impervious materials on or over the moving fourdrinier screen, an unlayered nonwoven fabric having, for example, alternating stripes of high fiber density areas can be produced by papermaking techniques wherein substan-tially all of the fibers in the high fiber density stripes are oriented in the direction of the fluid-impervious lines, and substantially all of the fibers in the low fiber density stripes are oriented in a direction substantially normal to that direc-tion. Since the short fibers are of insufficient length (pre-ferably 1/4") to bridge the fluid-impervious lines or areas, most of them will be deposited with substantially their full length within impervious areas on the collection screen so as to form "twistless ribbon strands". These areas also contain a ma-jority of the long fibers from a stock flow being fed thereto, while a lesser number of the long fibers bridge across the re-sist lines or areas and remain in a generally cross direction tothese resist areas or lines. A majority of the bridging long fi-bers have at least a portion of their length included in adjacent 1~45431 high density areas. The nonwoven fabric can be bound together in a number of ways, including the use of thermoplastic fibers as some of the short fibers therein, so that upon heating said thermoplastic fibers, they will bond the long bridging fibers at their ends where they are incorporated into the stripes but leave the bridging fiber itself substantially free of binder between the stripes, thus enhancing the drape and softness in these areas, while increasing the bulk of the high fiber density areas.
- 5a -1045431 - ~-BRIEF DESC~IPTIO`~J ~_T~E DP~_`JGS
Figure 1 shows a plan view of a nonwoven fabric made with the process of this invention.
Figure 2 is a flo~7 chart outlining the steps of the process of this invention.
DESCRIPTION OF THE PT'~EFERRE:D EMBODIM~,NTS
Referring to ~igure 1 of the drawings, there is shown an unlayered non~70ven fabric 10 having alternating high fiber density stripes 11 and low fiber density stripes 12. As can be seen in the drawing, the majority of the fibers in the high fiber density stripes 11 are oriented in a direction that substantially follows the direction of a moving fourdrinier screen upon which such a fabrlc is made (machine direction), that is to say, that those fibers are aligned substantially parallel to the length of the fabric. However, the majority of the fibers in the low fiber density stripes 12 are oriented in a direction that is substan-tially across the width of the fabric 10 (cross direction orientation), that is to say, these fibers are aligned sub-stantially normal to the fibers in the high fiber density stripes 11 and in bridging relationship with those stripes. These alternating striped portions of varying orientation are formed simultaneously as described below.
A non~70ven fabric such as shown in Figure 1 can be made by papermaking techniques wherein a stock of blended fibers comprising long fibers and short fibers are prepared and held in a chest at a particular consistency, ~hile being agitated to prevent settling and separation of the solids. The stock can then flo~7 to an inlet distribution s~stem ~Jhere the flow spreads to the full machine ~7idth, discharging the stoc]; into the headbo~, ~here the flow bccomes stabilized. ~t this point, the stabilized stock flow can then pass onto a moving fourdrinier ~7ire screen.
~4~431 The fourdrinier screen has fluid-impervious resist areas placed thereoll in various confiyurations, for example, continuous and parallel stripes. Thus, as the stock flow passes onto the fourdrinier screen, a majority of both the long and short fibers are drawn to the areas thereon outside the fluid-impervious resist areas, or in the case of the example, in between the fluid-impervious stripes. This, of course, would be espeially true of the short fibers since they would not be subject to forces of more than one of the areas outside of the fluid-impervious areas and would not attempt to bridge a fluid-impervious area.
P~ather, because of the movement of the fourdrinier screen, they will be increasingly drawn to the pervious portion of the screen and will be oriented in the direction of the fluid-impervious stripes, or parallel to the machine direction of the formed web.
Simultaneously, a minority of the fibers, especially the long fibers, will be subject to the forces of at least two fluid-pervious areas, thereby causing some of the long fibers to bridge across a fluid-im2ervious area. Thus, such fibers will be oriented in a direction substantially normal to the axis of
BACKGROUND OF THE INVENTION
This invention relates to biaxially oriented striped nonwoven fabrics and a method for making same, and more part-icularly, to a method of making a nonwoven fabric having al-ternating high fiber density and low fiber density striped portions, and fiber mixtures of both long and short fiber lengths, said fabric having substantially biaxial orientation of fibers throughout the fabric.
Nonwoven fabrics are now used for a variety of purposes in a number of industries. These fabrics have been made tradi-tionally by methods such as carding, garnetting, air-laying and the like. Nonwoven webs have been made to have most of the fibers therein oriented in the machine direction; other non-woven webs have been made to have some cross orientation; and still other webs have been produced having a randomized fiber distribution. However, sutstantially all of these webs are lacking in any surface character or natural decorative effect.
Nowhere in the art, heretofore, has a nonowoven fabric been made in an unlayered structure having a striped construction wherein half of the stripes have a high fiber density and the other half of the stripes are of low fiber density; further-more, no fabrics have yet been made in such a strip3d m~er, for example wherein a majority of the fibers in the high fiber density stripes are oriented in a direction parallel to stripes (machine direction~, while a majority of the fibers in the low fiber density stripes are oriented in a direction substantially perpendicular to the stripes (cross direction). No method has yet been devised for manufacturing such a fabric with at least two types of orientation disposed thereon simultaneously.
Furthermore, it has been discovered that while the bi-axially oriented nonwoven fabric described above has been very satisfactory in many respects, efforts have been undertaken to 104~43~
attempt to reduce the cost of raw materials therein, while increasing the bulk, softness, feel and look of the resulting nonwoven fabric. Thus, a papermaker's method for making this nonwoven, using short paper fibers, will reduce costs dramati-cally.
The invention provides a method of making biaxially oriented nonwoven fabrics having areas of low fiber density and high fiber density wherein a majority of the fibers in said low fiber density areas are oriented in a direction sub-stantially normal to the fibers in the directly adjacent highfiber density areas and a majority of the fibers in said high fiber density areas that lies directly adjacent said low fiber density areas are oriented in a direction substantially parallel with the contours of the configuration of the low fiber density area comprising: preparing a stock of blended long and short fibers, said long fibers being at least one-half inch in length or more and said short fibers being less than one-half inch in length; maintaining said stock of fibers in an agitated state;
causing a flow of said stock to pass into a headbox, and stabilizing same therein; passing said stabilized stock flow onto moving fourdrinier screen having fluid-impervious resist areas thereon; causing a majority of said long and said short fibers in said stock flow to locate outside said fluid-impervious resist areas, said majority of fibers that lie directly adja-cent said fluid-impervious resist areas orienting themselves in a direction substantially parallel with the contours of said resist areas; simultaneously causing a minority of said long and short fibers in said stock flow to locate across said fluid-impervious resist areas, said minority of said long and short fibers orienting themselves in a substantially cross direction normal to the axis of said fluid-imperious resist areas; secur-ing said biaxially oriented nonwoven fabric in said orientation B
as described herein; carrying said biaxially oriented nonwoven fabric on said moving fourdrinier screen toward a pick-up means fGr collecting the thusly formed fabric; and, collecting said fabric on said pick-up means. The nonwoven fabric with long and short fibers therein can have a striped patterned construction manufactured into it, which would be able to be produced with relatively inexpensive short fibered materials, The nonwoven fabric may have alternating stripes of high fiber density and low fiber density, wherein a majority of the fibers in the high fiber density stripes are oriented in the machine direction while a majority of the fibers in the low fiber density stripes are oriented in the cross direction. The direction of the stripes may run across the fabric or at some other angle that is bias to the angle of the direction of travel of the fabric.
By placing lines of fluid-impervious materials on or over the moving fourdrinier screen, an unlayered nonwoven fabric having, for example, alternating stripes of high fiber density areas can be produced by papermaking techniques wherein substan-tially all of the fibers in the high fiber density stripes are oriented in the direction of the fluid-impervious lines, and substantially all of the fibers in the low fiber density stripes are oriented in a direction substantially normal to that direc-tion. Since the short fibers are of insufficient length (pre-ferably 1/4") to bridge the fluid-impervious lines or areas, most of them will be deposited with substantially their full length within impervious areas on the collection screen so as to form "twistless ribbon strands". These areas also contain a ma-jority of the long fibers from a stock flow being fed thereto, while a lesser number of the long fibers bridge across the re-sist lines or areas and remain in a generally cross direction tothese resist areas or lines. A majority of the bridging long fi-bers have at least a portion of their length included in adjacent 1~45431 high density areas. The nonwoven fabric can be bound together in a number of ways, including the use of thermoplastic fibers as some of the short fibers therein, so that upon heating said thermoplastic fibers, they will bond the long bridging fibers at their ends where they are incorporated into the stripes but leave the bridging fiber itself substantially free of binder between the stripes, thus enhancing the drape and softness in these areas, while increasing the bulk of the high fiber density areas.
- 5a -1045431 - ~-BRIEF DESC~IPTIO`~J ~_T~E DP~_`JGS
Figure 1 shows a plan view of a nonwoven fabric made with the process of this invention.
Figure 2 is a flo~7 chart outlining the steps of the process of this invention.
DESCRIPTION OF THE PT'~EFERRE:D EMBODIM~,NTS
Referring to ~igure 1 of the drawings, there is shown an unlayered non~70ven fabric 10 having alternating high fiber density stripes 11 and low fiber density stripes 12. As can be seen in the drawing, the majority of the fibers in the high fiber density stripes 11 are oriented in a direction that substantially follows the direction of a moving fourdrinier screen upon which such a fabrlc is made (machine direction), that is to say, that those fibers are aligned substantially parallel to the length of the fabric. However, the majority of the fibers in the low fiber density stripes 12 are oriented in a direction that is substan-tially across the width of the fabric 10 (cross direction orientation), that is to say, these fibers are aligned sub-stantially normal to the fibers in the high fiber density stripes 11 and in bridging relationship with those stripes. These alternating striped portions of varying orientation are formed simultaneously as described below.
A non~70ven fabric such as shown in Figure 1 can be made by papermaking techniques wherein a stock of blended fibers comprising long fibers and short fibers are prepared and held in a chest at a particular consistency, ~hile being agitated to prevent settling and separation of the solids. The stock can then flo~7 to an inlet distribution s~stem ~Jhere the flow spreads to the full machine ~7idth, discharging the stoc]; into the headbo~, ~here the flow bccomes stabilized. ~t this point, the stabilized stock flow can then pass onto a moving fourdrinier ~7ire screen.
~4~431 The fourdrinier screen has fluid-impervious resist areas placed thereoll in various confiyurations, for example, continuous and parallel stripes. Thus, as the stock flow passes onto the fourdrinier screen, a majority of both the long and short fibers are drawn to the areas thereon outside the fluid-impervious resist areas, or in the case of the example, in between the fluid-impervious stripes. This, of course, would be espeially true of the short fibers since they would not be subject to forces of more than one of the areas outside of the fluid-impervious areas and would not attempt to bridge a fluid-impervious area.
P~ather, because of the movement of the fourdrinier screen, they will be increasingly drawn to the pervious portion of the screen and will be oriented in the direction of the fluid-impervious stripes, or parallel to the machine direction of the formed web.
Simultaneously, a minority of the fibers, especially the long fibers, will be subject to the forces of at least two fluid-pervious areas, thereby causing some of the long fibers to bridge across a fluid-im2ervious area. Thus, such fibers will be oriented in a direction substantially normal to the axis of
2~ the fluid-impervious resist areas.
If the striping bars or fluid-impervious resist areas are disposed fairly close together so that the distance between the bars is less than a flber length, and preferably less than one-half the length of a long fiber, the fibers that do not bridge the striping bars will be carried into a high fiber -density stripe or the pervious area that lies between the striping bars. As described earlier herein, a high fiber density stripe formed by a majority of the fibers is therefore induced to have a primary orientation along the axis of the striping bar.
104~431 The long fibers are, for the purposes of this invention, at least one-half inch in length or more. The short fibers used herein may be paper fibers, cotton linters, short thermo-plastic fibers, or the like, or combinations thereof, so long as the fibers are less than one-half inch in length. If short thermoplastic binder fibers are used, either alone or with other short fibers, then they too will be drawn into the high fiber density stripes and, when activated, will bond the long bridging fibers at their ends where thev are incorporated into the stripes, but will leave the bridging fiber itself substantially free of binder between the high fiber density stripes, thus enhancing drape and softness in those areas, and in the total fabric.
For the purposes of this invention, these high fiber density areas comprising long and short fibers are referred to as twistless ribbon strands herein, and sho~ld have at least one strand width I in spacing between the strands, but not so much space that the long fibers are not able to bridge thereacross. While it is true that some short fibers will be ~ound in the low fiber density areas mixed in with the long bridging fibers, a majority of the short fibers will be disposed within the twistless ribbon strands. Therefore, the low fiber density stripes will have a lower total fiber length per unit of area of short fibers therein than the twistless ribbon strands. Furthermore, most of the long bridging fibers will have at least a portion of their length in adjacent strands, connecting the twistless strands, thereby forming the nonwoven fabric.
In all but the lightest weight fabrics, the top of the fabric, that is the portion of the fabric furthest removed from the fourdrlnier screen, appears to be covered by a minor portion of long and short fibers positioned generally across the entire wid-th of the webs. ~s the fibers in the stoc~ flow position themselves on the fourdrinier screen and fluid-impervious resist areas, and become increasingly thick and pass off tne striping bars, the fluid-borne fibers become less generally controlled by the water's diverging action between fluid pervious and impervious areas, and then fall on the uppermost portions of the tnusly formed fabric in a some~hat randomized fashion. The web at this point can best be described as having high and low fiber density stripes having a somewhat randomized covering portion of long and short fibers integrated therewith. ~lowever, a majority of the fibers are still positioned in a striped fashion and in an orientation parallel to the length of the web.
If the striping bars are moved closer together and arranged so that they are spaced on, for example 3/4 inch centers, it becomes apparent that a much more pronounced ribbed structure is formed. By "ribbed structure", it is meant that the high fiber density stripes have so many fibers therein that this portion of the web structure becomes almost semi-circular in its con-struction, ~Ihile the low fiber density areas remain rather flat.
This arrangement could well be described as being a wash-board configuration. The fabrics produced by this invention have a variety of uses and could be used as disposable curtains or drapes' decorative narrow ribbons and for florist ribbons; sweatbands;
cling type bandages; disposable tablecloths and the like.
Of course, other designs of striping bars can be used in different arrangements to produce similarly biaxially oriented nonwoven fabrics. For example, impervious resist areas can be designed into the fourdrinier screen as a substitute for the striping bars. Resist areas can also be formed in the shape of a star, or the like, directly on the screen, so that as the portion of the screen carrying the fluid~impervious resist areas passes through the apparatus, and the fibers have been deposited thereon and run over the suction roll, the biaxial orientation of fibers will occur on and around the resist areas on the screen producing a rather uniaue fabric. The resist areas will be covered by fibers in a manner as to produce low fiber density areas wherein the fibers are oriented in a direction substantially across each of the finger-like extensions on the star, or normal to the particular configuration, for example, while the area of the fabric web directly adjacent the resist area will have fibers oriented in a direction substantially parallel with the contours of the configuration of the resist area, and the fibers on the rest of the web not affected by resist areas will have a random, cross or machine orientation as desired. Other con-figurations could also be made on the screen to produce other similar biaY.ially oriented patterns thereof.
If the length of the striping bars blocking the screen is reduced so that they do not extend so far as to cover the entire screen collecting surface, then a substantially random web will be formed on the unblocked screen surface causing a random web to become superimposed over and integrally connected with the striped web. The proportion of web weight that is striped and has been biaxially oriented, to tAe proportion of superimposed web that is random can, of course, be varied by adjusting the proportion of the screen that is blocked by the striping bars.
Of course, as stated and described herein earlier, resist areas may also be placed at any other angles, other than parallel or normal to the direction of travel of the screen to produce fabriss witn stripes at a bias to the direction of travel of
If the striping bars or fluid-impervious resist areas are disposed fairly close together so that the distance between the bars is less than a flber length, and preferably less than one-half the length of a long fiber, the fibers that do not bridge the striping bars will be carried into a high fiber -density stripe or the pervious area that lies between the striping bars. As described earlier herein, a high fiber density stripe formed by a majority of the fibers is therefore induced to have a primary orientation along the axis of the striping bar.
104~431 The long fibers are, for the purposes of this invention, at least one-half inch in length or more. The short fibers used herein may be paper fibers, cotton linters, short thermo-plastic fibers, or the like, or combinations thereof, so long as the fibers are less than one-half inch in length. If short thermoplastic binder fibers are used, either alone or with other short fibers, then they too will be drawn into the high fiber density stripes and, when activated, will bond the long bridging fibers at their ends where thev are incorporated into the stripes, but will leave the bridging fiber itself substantially free of binder between the high fiber density stripes, thus enhancing drape and softness in those areas, and in the total fabric.
For the purposes of this invention, these high fiber density areas comprising long and short fibers are referred to as twistless ribbon strands herein, and sho~ld have at least one strand width I in spacing between the strands, but not so much space that the long fibers are not able to bridge thereacross. While it is true that some short fibers will be ~ound in the low fiber density areas mixed in with the long bridging fibers, a majority of the short fibers will be disposed within the twistless ribbon strands. Therefore, the low fiber density stripes will have a lower total fiber length per unit of area of short fibers therein than the twistless ribbon strands. Furthermore, most of the long bridging fibers will have at least a portion of their length in adjacent strands, connecting the twistless strands, thereby forming the nonwoven fabric.
In all but the lightest weight fabrics, the top of the fabric, that is the portion of the fabric furthest removed from the fourdrlnier screen, appears to be covered by a minor portion of long and short fibers positioned generally across the entire wid-th of the webs. ~s the fibers in the stoc~ flow position themselves on the fourdrinier screen and fluid-impervious resist areas, and become increasingly thick and pass off tne striping bars, the fluid-borne fibers become less generally controlled by the water's diverging action between fluid pervious and impervious areas, and then fall on the uppermost portions of the tnusly formed fabric in a some~hat randomized fashion. The web at this point can best be described as having high and low fiber density stripes having a somewhat randomized covering portion of long and short fibers integrated therewith. ~lowever, a majority of the fibers are still positioned in a striped fashion and in an orientation parallel to the length of the web.
If the striping bars are moved closer together and arranged so that they are spaced on, for example 3/4 inch centers, it becomes apparent that a much more pronounced ribbed structure is formed. By "ribbed structure", it is meant that the high fiber density stripes have so many fibers therein that this portion of the web structure becomes almost semi-circular in its con-struction, ~Ihile the low fiber density areas remain rather flat.
This arrangement could well be described as being a wash-board configuration. The fabrics produced by this invention have a variety of uses and could be used as disposable curtains or drapes' decorative narrow ribbons and for florist ribbons; sweatbands;
cling type bandages; disposable tablecloths and the like.
Of course, other designs of striping bars can be used in different arrangements to produce similarly biaxially oriented nonwoven fabrics. For example, impervious resist areas can be designed into the fourdrinier screen as a substitute for the striping bars. Resist areas can also be formed in the shape of a star, or the like, directly on the screen, so that as the portion of the screen carrying the fluid~impervious resist areas passes through the apparatus, and the fibers have been deposited thereon and run over the suction roll, the biaxial orientation of fibers will occur on and around the resist areas on the screen producing a rather uniaue fabric. The resist areas will be covered by fibers in a manner as to produce low fiber density areas wherein the fibers are oriented in a direction substantially across each of the finger-like extensions on the star, or normal to the particular configuration, for example, while the area of the fabric web directly adjacent the resist area will have fibers oriented in a direction substantially parallel with the contours of the configuration of the resist area, and the fibers on the rest of the web not affected by resist areas will have a random, cross or machine orientation as desired. Other con-figurations could also be made on the screen to produce other similar biaY.ially oriented patterns thereof.
If the length of the striping bars blocking the screen is reduced so that they do not extend so far as to cover the entire screen collecting surface, then a substantially random web will be formed on the unblocked screen surface causing a random web to become superimposed over and integrally connected with the striped web. The proportion of web weight that is striped and has been biaxially oriented, to tAe proportion of superimposed web that is random can, of course, be varied by adjusting the proportion of the screen that is blocked by the striping bars.
Of course, as stated and described herein earlier, resist areas may also be placed at any other angles, other than parallel or normal to the direction of travel of the screen to produce fabriss witn stripes at a bias to the direction of travel of
3~ the fabrics.
~045431 Since it is obvious that many rnodifications and embodiments can be made in the above-d2scribed i.nvention without chanying the spirit and scope of the invention, it is intend~d that this invention not be limited by anything other than the appended claims.
~045431 Since it is obvious that many rnodifications and embodiments can be made in the above-d2scribed i.nvention without chanying the spirit and scope of the invention, it is intend~d that this invention not be limited by anything other than the appended claims.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of making biaxially oriented nonwoven fabrics having areas of low fiber density and high fiber density wherein a majority of the fibers in said low fiber density areas are oriented in a direction substantially normal to the fibers in the directly adjacent high fiber density areas and a majority of the fibers in said high fiber density areas that lies directly adjacent said low fiber density areas are oriented in a direction substantially parallel with the contours of the configuration of the low fiber density area comprising:
preparing a stock of blended long and short fibers, said long fibers being at least one-half inch in length or more and said short fibers being less than one-half inch in length;
maintaining said stock of fibers in an agitated state;
causing a flow of said stock to pass into a headbox, and stabilizing same therein;
passing said stabilized stock flow onto a moving four-drinier screen having fluid-impervious resist areas thereon;
causing a majority of said long and said short fibers in said stock flow to locate outside said fluid-impervious resist areas, said majority of fibers that lie directly adjacent said fluid-impervious resist areas orienting themselves in a direction substantially parallel with the contours of said resist areas;
simultaneously causing a minority of said long and short fibers in said stock. flow to locate across said fluid-impervious resist areas, said minority of said long and short fibers orienting themselves in a substantially cross direction normal to the axis of said fluid-impervious resist areas;
securing said biaxially oriented nonwoven fabric in said orientation as described herein;
carrying said biaxially oriented nonwoven fabric on said moving fourdrinier screen toward a pick-up means for collecting the thusly formed fabric; and, collecting said fabric on said pick-up means.
preparing a stock of blended long and short fibers, said long fibers being at least one-half inch in length or more and said short fibers being less than one-half inch in length;
maintaining said stock of fibers in an agitated state;
causing a flow of said stock to pass into a headbox, and stabilizing same therein;
passing said stabilized stock flow onto a moving four-drinier screen having fluid-impervious resist areas thereon;
causing a majority of said long and said short fibers in said stock flow to locate outside said fluid-impervious resist areas, said majority of fibers that lie directly adjacent said fluid-impervious resist areas orienting themselves in a direction substantially parallel with the contours of said resist areas;
simultaneously causing a minority of said long and short fibers in said stock. flow to locate across said fluid-impervious resist areas, said minority of said long and short fibers orienting themselves in a substantially cross direction normal to the axis of said fluid-impervious resist areas;
securing said biaxially oriented nonwoven fabric in said orientation as described herein;
carrying said biaxially oriented nonwoven fabric on said moving fourdrinier screen toward a pick-up means for collecting the thusly formed fabric; and, collecting said fabric on said pick-up means.
2. The method of claim 1 wherein said fluid-impervious resist areas are approximately equidistantly spaced-apart finger-like striping bars disposed on and over said screen, and includes causing said stock flow to form a nonwoven biaxially oriented fabric comprising alternating stripes of high fiber density and low fiber density, a majority of said long and short fibers in said stock flow locating between said finger-like striping bars, said majority of fibers orienting themselves in a substantially lengthwise direction parallel to the axis of said striping bars, and a minority of said fibers in said stock flow locating across said finger-like striping bars, said minority of fibers orienting themselves in a substan-tially cross direction normal to the axis of said striping bars.
3. The method of claim 2 wherein the distance between said striping bars is less than an average long fiber length.
4. The method of claim 2 wherein the distance between said striping bars is less than one-half of an average fiber length.
5. The method of claim 2 including causing a portion of said fabric to have generally cross-oriented fibers disposed across, and integrally with, the top of said striped fabric.
6. The method of claim 2 including causing a portion of said fabric to have generally randomized fibers disposed on, and integrally with, the top of said striped fabric.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/642,667 US4070235A (en) | 1974-09-17 | 1975-12-19 | Method of making biaxially oriented nonwoven fabrics |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1045431A true CA1045431A (en) | 1979-01-02 |
Family
ID=24577528
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA261,563A Expired CA1045431A (en) | 1975-12-19 | 1976-09-20 | Method of making biaxially oriented nonwoven fabrics |
Country Status (25)
| Country | Link |
|---|---|
| JP (1) | JPS609157B2 (en) |
| AT (1) | AT357860B (en) |
| AU (1) | AU504104B2 (en) |
| BE (1) | BE849548A (en) |
| BR (1) | BR7608473A (en) |
| CA (1) | CA1045431A (en) |
| CH (1) | CH625662GA3 (en) |
| DE (1) | DE2657336C2 (en) |
| DK (1) | DK145470C (en) |
| ES (1) | ES454403A1 (en) |
| FR (1) | FR2335631A1 (en) |
| GB (1) | GB1525790A (en) |
| GR (1) | GR62432B (en) |
| GT (1) | GT197644357A (en) |
| IE (1) | IE43992B1 (en) |
| IT (1) | IT1123045B (en) |
| LU (1) | LU76422A1 (en) |
| MX (1) | MX145203A (en) |
| NL (1) | NL7614069A (en) |
| NO (1) | NO764270L (en) |
| NZ (1) | NZ182911A (en) |
| PH (1) | PH12691A (en) |
| PT (1) | PT65936B (en) |
| SE (1) | SE429350B (en) |
| ZA (1) | ZA767517B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IN157644B (en) * | 1981-02-19 | 1986-05-10 | Portals Ltd | |
| US4770490A (en) * | 1986-08-07 | 1988-09-13 | Minnesota Mining And Manufacturing Company | Filament reinforced tape |
| SE9003679L (en) * | 1990-11-19 | 1992-05-20 | Moelnlycke Ab | PROCEDURE AND DEVICE TO MANUFACTURE A SPUNLAC MATERIAL AND ABSORBING DISPOSABLE ARTICLE INCLUDING SUCH MATERIAL |
| SE469896B (en) * | 1990-11-19 | 1993-10-04 | Moelnlycke Ab | Method and apparatus for producing spun lace material and a material thus produced |
| US5204158A (en) * | 1991-05-30 | 1993-04-20 | Chicopee | Irregular patterned entangled nonwoven fabrics and their production |
| ZA946570B (en) * | 1993-08-30 | 1996-02-28 | Mcneil Ppc Inc | Absorbent nonwoven fabric |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2986780A (en) * | 1954-04-07 | 1961-06-06 | Kimberly Clark Co | Method and apparatus for forming patterned webs |
| US3150416A (en) * | 1960-07-29 | 1964-09-29 | Kendall & Co | Method and apparatus for producing apertured non-woven fabrics |
| US3322617A (en) * | 1964-05-22 | 1967-05-30 | Dexter Corp | Paper making apparatus to form paper with a simulated woven texture |
| NL6608874A (en) * | 1965-08-24 | 1967-10-25 |
-
1976
- 1976-09-20 CA CA261,563A patent/CA1045431A/en not_active Expired
- 1976-11-25 MX MX167171A patent/MX145203A/en unknown
- 1976-11-26 IE IE2608/76A patent/IE43992B1/en unknown
- 1976-12-07 PT PT65936A patent/PT65936B/en unknown
- 1976-12-08 GB GB51271/76A patent/GB1525790A/en not_active Expired
- 1976-12-14 GR GR52401A patent/GR62432B/en unknown
- 1976-12-14 IT IT52609/76A patent/IT1123045B/en active
- 1976-12-16 JP JP51150415A patent/JPS609157B2/en not_active Expired
- 1976-12-16 NO NO764270A patent/NO764270L/no unknown
- 1976-12-17 BR BR7608473A patent/BR7608473A/en unknown
- 1976-12-17 PH PH19259A patent/PH12691A/en unknown
- 1976-12-17 NZ NZ182911A patent/NZ182911A/en unknown
- 1976-12-17 CH CH1594576A patent/CH625662GA3/en not_active IP Right Cessation
- 1976-12-17 AU AU20679/76A patent/AU504104B2/en not_active Expired
- 1976-12-17 DK DK569776A patent/DK145470C/en not_active IP Right Cessation
- 1976-12-17 SE SE7614229A patent/SE429350B/en not_active IP Right Cessation
- 1976-12-17 FR FR7638150A patent/FR2335631A1/en active Granted
- 1976-12-17 AT AT937476A patent/AT357860B/en not_active IP Right Cessation
- 1976-12-17 DE DE2657336A patent/DE2657336C2/en not_active Expired
- 1976-12-17 NL NL7614069A patent/NL7614069A/en not_active Application Discontinuation
- 1976-12-17 ZA ZA767517A patent/ZA767517B/en unknown
- 1976-12-17 LU LU76422A patent/LU76422A1/xx unknown
- 1976-12-17 BE BE173300A patent/BE849548A/en not_active IP Right Cessation
- 1976-12-18 ES ES454403A patent/ES454403A1/en not_active Expired
- 1976-12-20 GT GT197644357A patent/GT197644357A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DK145470C (en) | 1983-04-18 |
| FR2335631A1 (en) | 1977-07-15 |
| SE429350B (en) | 1983-08-29 |
| JPS609157B2 (en) | 1985-03-08 |
| ATA937476A (en) | 1979-12-15 |
| JPS5277211A (en) | 1977-06-29 |
| IT1123045B (en) | 1986-04-30 |
| BE849548A (en) | 1977-04-15 |
| GR62432B (en) | 1979-04-12 |
| ES454403A1 (en) | 1977-11-16 |
| NO764270L (en) | 1977-06-21 |
| AU504104B2 (en) | 1979-10-04 |
| BR7608473A (en) | 1977-12-20 |
| NZ182911A (en) | 1978-09-25 |
| DK569776A (en) | 1977-06-20 |
| AT357860B (en) | 1980-08-11 |
| LU76422A1 (en) | 1977-06-10 |
| GT197644357A (en) | 1978-06-13 |
| IE43992L (en) | 1977-06-19 |
| FR2335631B1 (en) | 1982-03-26 |
| DE2657336A1 (en) | 1977-06-30 |
| GB1525790A (en) | 1978-09-20 |
| SE7614229L (en) | 1977-06-20 |
| DE2657336C2 (en) | 1986-04-10 |
| NL7614069A (en) | 1977-06-21 |
| PH12691A (en) | 1979-07-18 |
| IE43992B1 (en) | 1981-07-15 |
| DK145470B (en) | 1982-11-22 |
| PT65936B (en) | 1978-06-14 |
| PT65936A (en) | 1977-01-01 |
| MX145203A (en) | 1982-01-14 |
| AU2067976A (en) | 1978-06-22 |
| ZA767517B (en) | 1977-11-30 |
| CH625662GA3 (en) | 1981-10-15 |
| CH625662B (en) |
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