US3038215A

US3038215A - Manufacture of apertured cellulosic products

Info

Publication number: US3038215A
Application number: US788116A
Authority: US
Inventors: Kenneth J Harwood
Original assignee: Kimberly Clark Corp
Current assignee: Kimberly Clark Corp
Priority date: 1959-01-21
Filing date: 1959-01-21
Publication date: 1962-06-12
Anticipated expiration: 1979-06-12

Description

June 12, 1962 K. J. HARWOOD MANUFACTURE OF APERTURED CELLULOSIC PRODUCTS 3 Sheets-Sheet l Filed Jan. 21

June 12, 1962 K. J. HARWOOD 3,038,235

MANUFACTURE OF APERTURED CELLULOSIC PRODUCTS Filed Jan. 21, 1959 3 Sheets-Sheet 2 "Hill "Hllm.

June 12, 1962 K. J. HARWOOD 3,038,215

MANUFACTURE OF APERTURED CELLULOSIC PRODUCTS Filed Jan. 21, 1959 3 Sheets-Sheet 5 3,038,215 MANUFACTURE OF APERTURED CELLULOSIC PRODUCTS Kenneth J. Harwood, Neenah, Wis., assignor to Kimberly- Clark Corporation, Neenah, Wis., a corporation of Delaware Filed Jan. 21, 1959, Ser. No. 788,116 15 Claims. (Cl. 19-161) This invention relates to an improved method and to apparatus for providing a plurality of openings of patterned configuration in fibrous material substantially to increase the porosity thereof.

A major object is to provide an improved method particularly adapted for the conversion of a non-woven sheet stock material comprised of fibers either substantially aligned in one direction or haphazardly disposed, to rearrange the fibers and increase the porosity thereof.

Another object is to provide. improved apparatus for converting a substantially non-forarninous fibrous weblike material to increase the porosity thereof by subjecting portions of the web to localized stresses which cause aperture forming ruptures therein with attendant reorientation and regrouping of fibers marginally of the apertures thus formed.

Another object is to provide continuous high speed apparatus for carrying out the above method on a low cost production basis.

A still further object is to provide an improved fibrous material particularly adapted for use as a sanitary napkin Wrapper or the like from low cost fibrous sheet material which, prior to conversion in accordance with the invention, lacks the required porosity for such'use.

Other objects and advantages will become apparent to persons skilled in the art, as will various modifications thereof without departure from the inventive principles as defined in the appended claims.

In the drawings:

FIGURE 1 is a side elevational view of apparatus showing the invention incorporated therein,

FIGURE 2 is a fragmentary enlarged plan view along line 2-2 of FIG. 1, illustrating the manner in which elongate apertures are formed in fibrous sheet stock,

FIGURE 3 shows in enlarged fragmentary detail the carding needles of the FIG. 1 apparatus with fibrous sheet stock entrained thereon,

FIGURE 4 shows in elevation, and partially sectionalized, apparatus having an alternate embodiment of the invention incorporated therein,

FIGURE 5 is a vertical section taken along line 5-5 of FIG. 4,

FIGURE 6 shows in fragmentary plan a sheet stock material modified by the apparatus of FIG. 4,

FIGURE 7 illustrates the converting end of apparatus similar to that shown in FIGS. 1 and 4 with another alternate embodiment of the invention therein,

FIGURE 8 shows in axial section the crowned pulley and associated card clothing of FIG. 7,

FIGURE 9 shows in elevation a blade-like needle em- I ployed in an alternate embodiment of the invention, and

FIGURE 10 shows in fragmentary plan a plurality of the needles of FIG. 9 after the free ends thereof have moved apart to modify fibrous material impaled thereon.

Referring to FIG. 1, a roll of stock material 12, as for example a non-woven fibrous webbing to be treated in accordance with the invention, is rotatably mounted on a suitable spindle 14. Material 12 is led downwardly and partially about the circumference of a suitable feed roll 16 the outer portion 18 of which may be formed of foamed rubber or of other material such as screening which renders that portion of the roll readily pierceable by a plurality of moving needles 20 or the like to impale mate- 3,@38,2l5 Patented June 12, 1962 rial 12 on outer portions of the needles as the material is continuously drawn downwardly by the needles as they move away from roll 16. Needles 20 are mounted to a flexible endless belt 22 to extend outwardly therefrom, the needles being suitably fastened to the belt as in a known type of card clothing. Belt 22 is mounted taut between two spaced rolls or

pulleys

24 and 26, suitably journalled at 28 and 30 respectively, one of which, such as roll 26, drives belt 22, with roll 24 preferably serving as a belt positioning idler. The manner in which the rolls are mounted and driven is optional, hence is not illustrated. The needles assume a parallel spaced relationship throughout the upper and lower linear portions of the belt, but their free ends are forced to diverge, one from the other, as the belt moves from a linear path portion into either of the arcuate paths defined by the rolls, since the free ends of the needles must then move through the arc of a circle of greater radius than do the fixed bases of the needles.

Roll 26 is driven clockwise as shown, hence the upper belt portion moves from left to right from roll 24 to roll 26, and since that portion of the belt path is linear, needles 20 assume a parallel spaced relationship on entering it and remain in parallel relation until their supporting belt portion moves onto the roller 26 and starts to pass through the circumferential circle thereof. At that point each needle starts to diverge laterally from its trailing needle, the base of which has not yet entered the arcuate path. Since as shown in FIG. 2 a plurality of needles preferably are disposed in rows transversely of belt 22, all of the free ends of the needles in one row thus diverge in unison from the needles of the trailing row. As material 12 is impaled on the plurality of needles which continuously move from roll 24 to roll 26, one or more rows of those needles is at all times anchored against tilting, since the free ends thereof are held in pierced engagement with roll 16. The entire group of parallel needles between

rolls

24 and 26 are thus constrained against tilting as a unit, hence resist the forces imparted thereto in the machine direction as each transverse row of needles is caused outwardly to diverge by the driving force of roll 26 during initial travel through the arcuate path defined by that roll.

As best shown in FIG. 3, the needles of each row thus move clockwise at a more rapid rate than does the impaled material to cause reorientation of the fibers of material 12 as elongate apertures, shown at 32, FIG. 2, a e formed therein. In FIG. 3 the needle configuration 20a represents the position of each needle in a transverse row as it reaches the end of the linear belt path between

rolls

24 and 26. The extent to which the outer end of the needle is spread circumferentially in a clockwise direction is illustrated by its heavy line position 2011, that position being assumed on full entry of its associated belt portion into the arcuate path circumferentially of roll 26.

Rows of apertures 32, as shown in FIGS. 2 and 3, are thus formed in material 12. As the needles of each row complete their aperture forming function and move clockwise about roll 26, the next row of needles provide a trailing row of apertures. The apertures are thus formed during needle travel through the initial portion of circumferential path of roll 26, there being no further relat-ive movement between the free ends of needles in each successive row until the needles in one row complete their parti-circular path around roll 26 to enter the linear return path between

rolls

26 and 24. The opposite effect is of course obtained as each row of needles completes the circumferential path portion and enters the lower linear return portion of belt travel. As their outer ends undergo decelerated circumferential speed, the free ends of the needles thus return to their original parallel spaced relationship as shown in FIG. 1. The material 12 is maintained under suificient tension in its direction of forward movement, such as by known re-wind or other apparatus, not shown, to remain impaled on needles 20 until it is removed therefrom by a take-off roller 34. Return of the needles at the bottom of roll 26 from a laterally diverged to a parallel relation is accompanied by a repositioning of the outer needle ends from the leading ends of the slot-like apertures which they have formed toward the trailing ends thereof, the extent of such return being a function of the amount of permanent stretch which the material has undergone due to processing in the manner above described.

FIGS. 4 and illustrate an alternate embodiment of the invention wherein the material impaling needles are caused first to diverge outwardly in the machine direction, to then return to parallel relationship, and thereafter to diverge outwardly in the cross direction. An elongate frame 36 provides support for a driven roll 38 and an idler roll 40, the rolls being journalled at opposite ends of the frame, preferably in a horizontal plane to position and drive a flexible card clothing consisting of a conveyor belt 42 for the support and conveyance of a plurality of needles 44 through an elongate path, the belt moving in a general clockwise direction as shown. The material 46 to be converted is drawn from a stock roll 48 around a pierceable roll 50 to be impaled, in the manner taught by the FIG. 1 structure, on needles 44. The material is apertured in the machine direction in the manner above described as the needles outwardly diverge in that direction during their initial movement into the circumferential path of driven roll 38. The resulting material conversion thus far parallels that shown in FIG. 2 with transverse rows of elongate apertures formed and aligned in the machine direction. As belt 42 leaves roll 38 to move into its return path toward roll 40 it is guided downwardly into a non-planar configuration by a transversely arced shoe 52. A slight divergence of those needles at the center of the web in the machine direction may then occur, as shown between needles 44a and 44b, FIG. 4, but those needles return to a parallel relationship shortly thereafter. However, since the same needles have previously formed elongate machine directional apertures in the material, such momentary divergence, since unobstructed, does not further alter the material. However, as the belt moves into full engagement with the transversely arcuate shoe surface it is gradually flexed transversely into full conformance therewith as shown in FIG. 5. Belt 42, in changing from a linear to a downwardly convex transverse configuration during its movement onto the shoe results in those needles in each row laterally of the center needle being outwardly diverged in the cross direction.

As shown in FIG. 5, the needles are equally spaced transversely of the belt, with an odd number of needles employed to provide a pair of symmetrical banks laterally of each center needle. Symmetrical divergence of the needles of each bank in respect to both the center needle and each other results in the establishment of equal and opposite forces each side of center with the resultant neutralization thereof, hence there is no tendency toward a distortion or lateral displacement of the belt in its movement over the shoe. A madual divergence of the free ends of the needles in each row is thus established in planes transverse to the machine direction, with the result that the fibrous material is provided with a plurality of elongate apertures 56, FIG. 5, extending laterally of the trailing ends of the elongate machine direction apertures previously formed as above described.

The resulting apertures of right angular configuration are shown at 56, FIG. 6, the machine direction portions thereof previously formed as the needles moved over drive roll 38 being shown at 58. It will be noted that the center longitudinal row of apertures 58a extends solely in the machine direction since the center needles as shown at 44a, FIG. 5, have not been subject to lateral displacement as above stated. After completion of its travel over shoe 52, the needles return from a laterally divergent to a parallel relationship and the material so processed is removed from the needles by a suitably positioned take-oil roll for further processing or windup. The extent to which the material being processed is permanently stretched, both in the machine and cross direction, depends upon several factors including the nature of the material, the length of needles, and the degree of curvature of the arcuate path through which the needles move apart.

FIGURES 7 and 8 illustrate an apparatus incorporating an alternate embodiment of the invention wherein the free ends of those needles on each side of the longitudinally extending center row simultaneously spread apart in both machine and cross direction. FIGURE 7 shows the material converting end of the driven belt type conveyor of a known type but having a belt 72 driven by a crowned pulley 74 suitably mounted for driven rotation on a shaft 76. Pulley 74 is constructed with an outwardly convex arcuate surface 78 forming a crown over which belt 72 is drawn, gradually to become contoured in conformance with the pulley configuration. During movement of the belt toward the pulley, which is driven in the clockwise arrow direction shown, lateral portions of the belt are drawn downwardly toward the corresponding radially reduced lateral portions of the pulley, gradually to transversely flex the belt into an upwardly convex configuration. Since there is no such downward movement along the center line of the belt, that portion continues its linear path as shown at 72a until it reaches the corresponding center portion of pulley 74 to enter the arcuate machine directional path circumferentially of the pulley. From the point of downward curvature of the lateral belt portions, and continuing until the belt has engaged corresponding lateral portions of the pulley, the free ends of the needles supported by those belt portions gradually move apart from their original positions in which the needles are in parallel spaced relation both longitudinally of and transversely of the belt ultimately to assume the transverse configuration shown in FIGURE 8. The outer end of each of the needles such as needle 80 positioned laterally of the center row needles are spread apart in respect to the center needle 80a, and from each other in the divergent relation shown as the free needle ends thus spread, hence they form laterally extending apertures as shown at 82 in the material 12 impaled thereon. Since the transverse arcing of each side of the belt is accompanied by a gradual longitudinal arcing of the belt as those needles at each side of the center line of the belt approach pulley 74, the lateral spreading of outer needle portions is also accompanied by some machine directional spreading prior to actual belt engagement with the pulley surface. However, the center line needles will not spread longitudinally as above taught until the center portion of the belt moves into circumferential contact with its corresponding pulley portion. Simultaneous spreading of the needles in both the machine and cross direction results in the aperturing of material 12 in somewhat the manner shown in FIG. 6, but the apertures so produced are somewhat modified in respect to those shown since the needles spread obliquely of the center line with the extent of spread as well as the oblique angularity of needle movement progressively increasing outwardly of the center line to produce a symmetrical pattern of pleasing appearance. It is thus seen that a somewhat different pattern is obtained when the needles are moved apart simultaneously in both a machine and cross direction, as by the structure of FIGS. 7 and 8 than when they are first moved apart in the machine direction, returned parallel, and then moved apart in the cross direction, as shown in FIG. 4.

While the needles may be of a known carding type, if of sufficient strength and suitably attached to their associated belt to operate as above described, it may be preferable to provide outer portions thereof with radially 5 extending shoulders as shown at 86, FIG. 3, upon which {material 12 rests after being pierced by the needle ends to insure that the material is carried along the linear portions of the conveyor to a common plane, and to further insure that as the needle ends move apart during the arcuate path portion, the material maintains its position rather than being pulled inwardly of the needles which would result in a reduction of efiective needle length with consequent shortening of the apertures formed in the longitudinal direction by the devices of FIGS. 1 and 4, and a reduction of aperture length in the cross direction by the devices of 4 and 7.

While the apparatus shown in FIGS. 4 and 5, as well as that shown in FIGS. 7 and 8 opens up the material in both the machine and cross directions, either by a two stage operation or simultaneously as above described, the FIG. 1 apparatus, for example, may be modified to produce relatively wide apertures with needle spreading only 1n the machine direction. This may be done by use of flat shanked knife-like needles 87 as shown in FIGS. 9 and 10. Needles 87 are attached to the conveyor belt with the ma or planes of the blades extending transversely of the belt. As the material 12 is impaled on needles 87, transverse slits are cut into the material which are then m the non-diverged positions shown dotted at 90, FIG. 10. As the needles enter the arcuate path portion to be spread apart in the manner above described, relatively wide apertures 92 are formed therein as the fibers are displaced by the edges of the flat needle blade portions driving forward, spreading one from another, in the machine direction. I

As will be evident from the manner in which the processed sheet material forcibly is apertured, a reorientation of portions of the material occurs marginally of those apertures. The processing of sheet material of the non-woven type comprising cellulosic or other fibers which have been haphazardly disposed by either fluid or air laying techniques, results in the re-orientation of the fibers thereof marginally of the apertures. Such material is conventionally formed into a fabric as by a pressing operation which results in intertwining of the fibrils, or by otherwise interbonding at least a portion of the fibers. Some such materials are formed of a mixture of fibers, some of which are of the thermoplastic type, the sheet material being subjected to sufiicient heat after the formation thereof to bond the thermo-plastic fibers together. It is known also to apply liquid adhesives in the form of a vapor or by printing techniques to render air laid fibers, for example, sufliciently interbonded to provide a serviceable fabric. Since the provision of apertures therein as above described involves a forcible separation of the fibers in those areas. in which the apertures are formed, a substantial nunrber of the fibrous bonds of one type or another in those areas are of course destroyed.

As the needles move apart forcibly to produce elongate apertures a destruction of interfibrous bonds is accompanied by a re-orientation of those fibers which are in the path of the expanding needles. Such re-orientation results in a fibrous build-up marginally of the apertures thus defined, which may be relatively ragged in respect to aperture margins otherwise formed, but which is of increased thickness in respect to the average fibrous deposits throughout the material being processed. Such re-orientation of the fibers strengthens the material in the direction of aperture length due to a fibrous build-up marginally thereof. Hence when elongate apertures are provided to extend in the machine direction only, an increase in machine directional strength is accompanied by a decrease in cross directional strength. When the apertures are formed by needles which move apart in both directions there may be no substantial change of cross direction in respect to machine directional strength, provided the cross directional needle expansion is about the length of the machine directional expansion.

The fibrous re-orientation above described has a marked effect on the direction of maximum fluid flow throughout fibrous material thus processed in addition to substantially increasing the porosity thereof. The invention therefore is ideally suited for the processing of fibrous materials used in sanitary napkins. As above mentioned, machine directional aperturing increases both porosity and machine directional strength, hence fibrous material so processed is highly effective as a sanitary napkin wrapper, and maximum fluid flow is then in the desired machine direction. Inner layers used in sanitary napkin construction may be selected on the basis of increased fluid flow in the cross direction and as is quite evident, fibrous webbing-like material may be rapidlyaltered to increase those properties by impaling the material on card clothing and flexing the belt only in the cross direction as herein taught.

It has been found in practicing the invention that best results are obtained when the material being processed has been dampened prior to being impaled on the needles. While water dampening works Well, the material may be dampened by a liquid binding agent such as polyethyl alcohol or the like which serve first to facilitate fiber reorientation, and upon subsequent drying provides interfiber bonds to strengthen the processed material.

The invention, therefore, has wide applicability in respect to the processing of various types of fibrous sheet material for the purposes above stated. The invention is not limited in respect to the type of material under treatment, and it is contemplated that it might be desirable to treat certain light-weight non-fibrous sheet stock in the manner taught herein to improve the porosity and other characteristics thereof.

1 claim:

1. The method of increasing the porosity of a fabriclike material consisting of the steps of continuously impaling portions of the material onto outer end portions of a plurality of spaced needle-like elements while causing said elements continuously to move through a predetermined path which includes a planar portion through which the elements move during impaling of the material thereon, and an arcuate portion downstream from the impaling position through which the needles thereafter move, whereby the elements are caused to diverge during passage through the arcuate path portion and thus form a plurality of apertures in the material.

2. The method of claim 1 wherein said needles are caused to move apart in their direction of travel.

3. The method of claim 1 wherein said needles are caused to move apart transversely of the direction of continuous needle travel.

4. The method of claim 1 wherein said needles are caused to move apart both in their direction of travel and in a cross direction in respect thereto.

5. The method of increasing the porosity and machine directional strength of fabric sheet stock consisting of impaling the stock on the free ends of continuously moving needles fixed at one end to an elongate element movable through a closed path and having portions diverging from the free ends thereof toward their bases to define flat blade-like shanks, the major planes of the shanks being positioned to extend transversely of the direction of needle travel to slit the stock in a cross direction during impaling thereof on the needles, and then causing the needles to move through an arcuate path to force the slit forming portions thereof apart sufficiently to subject the stock to forces exceeding the elastic limit thereof to reform the stock material marginally of the needle shanks and define apertures in the stock.

6. The method of increasing the porosity and machine directional strength of fabric-like material consisting. of the steps of piercing the material with needle-like elements aligned for movement in a machine direction, continuously moving the elements in the machine direction,

and expanding the material engaging port-ions of the elements sufficiently to subject the material to force exceed ing the elastic limit thereof to reposition fibers thereof marginally of apertures thus formed in the material.

7. Apparatus for processing sheet stock material to provide apertures therein by repositioning of the stock material, including in combination, a conveyor for impaling and continuously moving said stock material through a closed path having first and second linear portions and an intermediate arcuate portion, said conveyor comprising a continuously moving flexible member and a plurality of needle-like elements fixed to and extending outwardly therefrom in parallel spaced relation during movement of said member through the first linear path portion, the free ends of said elements being caused to diverge in respect to their fixed ends during movement of said member through the arcuate path portion, means for impaling a continuously moving sheet material on the free ends of said elements during movement through said first linear path portion, and means for withdrawing said material from said elements during movement thereof through said second linear path portion.

8. In apparatus of the character described, an endless flexible conveyor member, means for continuously moving said member through a predetermined closed path, a plurality of spaced card needles, the bases of which are fixed to said member in patterned configuration with the pointed ends thereof extending outwardly therefrom, said conveyor moving means including an axially crowned pulley over which said member moves in traversing said closed path for the movement of said member through the arc of a circle in its direction of travel while transversely arced, means for impaling sheet stock on the pointed end portions of said needles prior to needle movement over said pulley, and means for withdrawing the impaled sheet stock from said needles after movement thereof over said pulley, whereby the pointed ends of said needles are caused to move apart, one from the other, in both the direction of and in a direction transverse to the path of travel during the movement over said pulley to provide apertures in said sheet stock.

9. In a device of the character described, an endless flexible conveyor member, a plurality of spaced needles fixed to said member to extend outwardly therefrom, means for the continuous movement of said member in a predetermined path, said means including a cylindrical driving element for said conveyor member over which said member moves during its continuous movement in said path, a shoe spaced from said driving element and positioned for movement of said conveyor member thereover in a transversely arced configuration, means for impaling sheet stock on outer portions of said needles prior to conveyor member movement thereof over said driving element and shoe, and means for the removal of said sheet stock after completion of conveyor member travel over said driving element and shoe, whereby said needles are caused to diverge in planes aligned with the path of travel during conveyor member movement over said driving element and are caused to diverge in planes transversely of the path of travel during conveyor member movement over said shoe.

10. The device of claim 9 wherein said shoe is positioned to trail said cylindrical driving element in the path of conveyor member travel.

11. In a device of the character described, an endless flexible card clothing comprising a flexible endless belt to which is attached a plurality of card needles extending outwardly therefrom in substantial parallel spaced relation when their associated belt portion assumes a planar configuration, means for the continuous movement of said belt through a path having first and second planar portions and an intermediate arcuate portion to cause the free ends of the needles first to move from a parallel to an outwardly divergent relationship and then to return to parallel relationship, means for continuously moving a fabric-like sheet stock at a speed synchronized with the rate of movement of said needles, means for continuously impaling said stock on the freee ends of said needles when traveling through the first planar path portion in parallel relationship for conveyance by said belt through said path and means for removing said stock from said needles when traveling in the second planar path portion in parallel relationship.

12. The device of claim 11 wherein each said needle has a blade-like shank portion leading to a pointed free end, and the major planes of said shank portions extend transversely of the direction of needle travel.

13. The method of increasing the porosity and machine directional strength of fibrous fabric-like material consisting of the steps of puncturing the material with needle-like elements aligned in the machine direction, and spreading apart the material engaging portions of the elements in the machine direction sufliciently to rupture the material and form apertures therein while repositioning fibers thereof marginally of the apertures thus formed in the fabric. I

14. Apparatus for the re-orientation of randomly positioned fibers in fabric material in a manner to provide plural apertures therein in patterned configuration, said apparatus having in combination, an endless flexible belt, a plurality of rigid needles having bases fixed in patterned configuration to said belt and free ends extending outwardly therefrom, means for driving said belt through a path including first and second planar portions and an intermeditae arcuate portion with the needles in parallel relation during movement through said first planar portion and then in outwardly divergent relation during movement through said arcuate portion and, then returned to parallel relation during movement through said second planar portion, means for feeding a fabric material to the free ends of the needles when in said first parallel relation, means for forcing the fabric material downwardly of the needles for puncture thereby and support of the fabric material on the free end portions of the parallel needles for movement of the fabric material through the intermediate arcuate path portion and into the second planar path portion for return of the needles from a spaced apart to a parallel relation.

15. Apparatus for altering a fibrous sheet stock comprising in combination, a continuous belt, a plurality of card needles fixed to extend outwardly from said belt, means for continuously driving said belt through a path having first and second linear portions through which said needles travel in parallel spaced relation and an arcuate portion therebetween through which said needles travel in outwardly diverged configuration, a pierceable roll for continuously feeding sheet stock to said needles when traveling through the first linear path portion in parallel spaced relation for conveyance of said stock from said linear portion through the arcuate path portion, and a removal roll for withdrawing the stock from said needles after conveyance thereof through said arcuate path portion and movement into said second linear path portion, whereby said stock is apertured in the machine direction by the relative divergence of said needles.

References Cited in the file of this patent UNITED STATES PATENTS 202,252 Field Apr. 9, 1878 1,345,693 Pye July 6, 1920 1,737,607 McDermott Dec. 3, 1929 1,770,252 Robertson et al. July 8, 1930 1,857,281 Johnson May 10, 1932 2,709,282 Lindel et a1 May 31, 1955 2,845,687 Howard Aug. 5, 1958