US 3775244 A
An apparatus for manufacturing nonwoven textile webs from an aqueous dispersion of fibers including an endless flexible porous belt, a headbox positioned to deliver the aqueous dispersion to the belt, and at least one suction device having a removable and perforated mask, the perforations of the mask being aligned and arranged parallel to the direction of travel of the porous belt. The suction device is located on the opposite side of the belt from the headbox and is conterminous with the headbox.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Hubschmann Nov. 27, 1973 APPARATUS FOR MANUFACTURING NONWOVEN TEXTILES  Inventor: Johann Hubschmann, Lyon Ler,
France  Assignee: Societe Rhodiaceta, Paris, France  Filed: Oct. 14, 1971  Appl. No.: 189,155
 US. Cl 162/351, 162/109, 162/116, 162/208, 162/211, 162/353, 162/365  Int. Cl. D211 1/52  Field of Search 162/351, 365, 211, 162/217, 363, 374, 355, 356, 208, 209, 115,
 References Cited UNITED STATES PATENTS Walser 162/351 Start et al. 162/365 3,190,790 6/1965 Ploetz et al. 162/351 X 2,543,870 3/1951 Robbins 162/374 1,155,853 10/1915 Weston 162/109 X Primary Examiner-S. Leon Bashore Assistant Examiner-Richard V. Fisher AttorneyLeonard W. Sherman et al.
[5 7] ABSTRACT An apparatus for manufacturing nonwoven textile webs from an aqueous dispersion of fibers including an endless flexible porous belt, a headbox positioned to deliver the aqueous dispersion to the belt, and at least one suction device having a removable and perforated mask, the perforations of the mask being aligned and arranged parallel to the direction of travel of the porous belt. The suction device is located on the opposite side of the belt from the headbox and is conterminous with the headbox.
7 Claims, 10 Drawing Figures PATENIEDNUYZY 1975 3.775244 SHEET 10F 2 oo ood oodioooi;
APPARATUS FOR MANUFACTURING NONWOVEN TEXTILES The present invention is directed to a device for the manufacture of nonwoven textile webs. More particularly, the present invention is directed to a device for the manufacture of nonwoven textile sheet material utilizing paper making techniques, which sheet material has the appearance and characteristics of woven fabric.
Attempts have been made to utilize paper making techniques for forming fibrous sheets of nonwoven material having the appearance and characteristics of woven products. These attempts were directed toward the production of nonwoven web material having a variation of fiber density over the surface so as to give the impression of alternating high fiber density areas and low fiber density areas as in a piece of woven material. Generally, the processes and apparatus utilized to obtain these sheet materials consist in depositing fibers in certain areas of the sheet in a higher density utilizing a special filtering belt having a fine bottom or base seive covered with a second seive or screen having larger apertures. The fibers are deposited on the belt by means of the suction created by a suction box placed under the belt. Although these processes and the special filtering belt produce nonwoven fabric materials having the appearance of woven fabric, certain disadvantages'are apparent, such as, the difficulty in separating the nonwoven sheet formed from the supporting web or belt, because'the individual fibrous materials interweb, mesh, and bind themselves to the porous web utilized to form the material. Furthermore, the fabric to be produced was limited to the pattern on the upper screen. This made the process andapparatus heretofore used of limited utility and severely limited the versatility of the same with respect to changing pattern and design. The latter could only be achieved by changing the entire upper screen which was a costly and time consuming operation.
The apparatus of thepresent invention permits the production of nonwoven fibrous materials utilizing a paper making or wet laid technique without the corresponding disadvantages previously encountered.
Briefly, the apparatus of the present invention includes at least one head box, at least one suction device conterminous with said head box comprising means to create a suction parallel with relation to the direction of the travel of the porous belt, and a porous, endless forming belt positioned between said head box and said suction device. 7 i
It is, therefore, the principle object of the present invention to provide an improved device for the production of a nonwoven web utilizing a paper making-wet laid technique.
It is a further object of the present invention to provide a device wherein the pattern produced in the nonwoven webs may be varied by a simple and inexpensive adjustment.
It is a still further object of the present invention to provide a device for producing nonwoven webs having areas of high fiber density andareas of low fiber density.
Still further objects and advantages of the device of the present invention will become more apparent from the attached drawings and description of the same wherein:
FIG. 1 is a diagrammatic representation of the device of the present invention;
FIG. 2 is a top view of a removable mask suitable for use in the device of the present invention;
FIGS. 3, 4, and 5 are top views of alternative masks suitable for use with the device of the present invention;
FIGS. 6, 7, and 8 are diagrammatic illustrations of nonwoven textile materials produced using the device of the present invention;
FIG. 9 is a top view of a suction box with the removable mask in-position; and
FIG. 10 is a view along line l0l0 in FIG. 9.
FIG. 1 is a diagrammatic illustration of a paper making machine embodying the device of the present invention. FIG. 1 shows a head box 12 containing a fibrous dispersion ll. I-Iead box 12 may be any conventional head box which utilizes gravity to deposit the dispersion on a filtering belt, such as endless filtering belts, which forms a portion of the bottom of head box 12. The remainder of the bottom of head box 12 comprises walls 14 and 15 which provide an opening in head box 12 for the deposition of dispersion l on belt 2. The fibrous dispersion is formed into nonwoven web 3 on filtering belt 2 by means of suction device 4 which has a removable mask 5 at its upper surface, i.e. that portion of suction device 4 closest to belt 2. A more detailed view of suction device 4 and mask 5 is shown in FIGS. 9 and 10. The suction is produced in suction device 4 by any conventional suction producing means such as suction pump 19. Although not essential to the successful operation of the apparatus of this invention, it is preferred that the effective suction area of suction device 4 on belt 2 be substantially the same as the size of the opening in head box 12 and the effective suction area is substantially conterminous with the head box opening.
Referring to FIGS. 25, which show various modifications of the upper'porous'mask surface 5 of suction device 4, a series of apertures 6, 6, 6", and 6" can be seen. The spacing and shape of these apertures is not especially critical and the apertures can be in any arrangement and shape so long as the rows lie parallel to the direction of travel of flexible web 2.
These apertures 6, 6', 6" and 6" on the upper side of suction device 4 create preferential passagesays for the fluid in which the fibers are dispersed in head box 12. These preferential passageways cause substantial deposits of the fibers on a conveyor belt in the area of these preferential passageways while there are more or less minimal deposits of fibers on the areas of the belt without the preferential passageways.
Although FIG. 1 illustrates a paper making machine having only one head box, this embodiment is not to be taken as limiting sincethe apparatus of the present invention may utilize a paper making machine having two or more separate head boxes for depositing fibrous materials on flexible porous belt 2. Furthermore, it is not necessary that all head boxes be equipped with the suction box of the present invention since only one such suction box is necessary to produce the ribbed or varying pattern as shown in FIGS. 6 and 7. However, it should be noted that if two head boxes are utilized, both equipped with suction devices, the number of designs which may be imparted to the nonwoven web can be increased greatly since, if either or both suction devices include means for moving the suction devices in a direction transverse to the direction of travel of said belt, overlapping and crossing ribs may be produced, thereby permitting varied ornamental and nonwoven webs to be produced, such as shown in FIG. 8.
If, however, only one head box is equipped with the suction device of the present invention, a fainter or less accentuated design will be produced since the fibrous material will be dispersed evenly from one head box and the pattern design will be partially masked by this even deposition.
Although it is not necessary to utilize a paper making machine with an inclined contacting area as shown diagrammatically in FIG. 1, since any type of paper making machine arrangement wherein the substantially entire suction area is in contact with the fibrous dispersion may be used, this type of machine is generally preferred.
Referring to FIGS. 6, 7, and 8, which show diagrammatic views of nonwoven fabrics produced utilizing the device of the present invention, it should be noted that the thickness or width of high density areas 7, 9, and l l and low density areas 8, 10, and 13 depends upon the draining or dripping speed of the fibrous suspension. This draining speed also varies according to the strength of the suction and the type of fibers in the suspension.
The device of the present invention generally produces articles which have strips with a high density a1- ternating with strips having a low density of fibers. If the suction box 21 and mask are stationary, the strips are generally in the form of parallel longitudinal strips, as shown in FIG. 6. If, however, the suction from suction device 4 is intermittent, these high density strips may be crossed transversely by low density areas. If the suction box is movable having a reciprocating movement transverse to the direction of travel of the porous, endless belt 2, then a nonwoven fabric such as illustrated in FIG. 7 will be produced wherein the high and low density strips are in the form of zig-zag, sinusoidal curves, etc. with the amplitude corresponding to the amplitude of the translational movement of the suction box with respect to the endless, porous belt 2.
FIG. 8 illustrates a nonwoven fabric produced utilizing two head boxes and two reciprocating suction devices and shows one of the varied effects which can be produced. It should be noted that the amplitude and frequency of either suction box can be varied independently thereby producing a number of interesting and varied designs.
FIGS. 9 and 10 are more detailed views of the suction device arrangement of the apparatus of the present invention. At the top of the suction box 21 of suction device 4 is a pair of U-shaped grooves 17 and 17' which mate with projections 16 and 16' on mask 5. Set screws 18 and 18 project into grooves 17 and 17' and contact projections 16 and 16' holding mask 5 firmly in place. To change the pattern of the nonwoven web to be formed, the set screws 18 and 18 are loosened and mask 5 is replaced with a similar mask with a different arrangement of size perforations. Mask 5 is formed from any rigid material such as metal or plastic. Furthermore, device 4 may be either fixed or equipped for a reciprocating translational motion transverse to the direction of travel of belt 2. Motion effecting means 20 is shown in FIG. 1 and may be any conventional means for example, a cammed motor drive or a double-acting fluidic cylinder.
The device of the present invention is useful for producing nonwoven sheets from a number of fibrous dispersions, including natural, artificial, synthetic fibers or mixtures thereof. Also the fibers may be mixed with conventional paper fibers as long as the length is greater than the so-called paper making fibrous length. Therefore, any synthetic fiber having a length between 2 and mms. or more, and preferably between 5 and 40 mms., can be used.
After nonwoven sheet 3 is formed on the device of the present invention, it is removed from endless, porous belt 2 and may be treated with conventional finishing treatments such as dyeing, printing, or coating. Furthermore, these sheets may be laminated together or the sheet may be folded upon itself with these various layers of the same material being subsequently bonded.
The use of the device of the present invention will be now illustrated with reference to the following nonlimiting example.
EXAMPLE A paper making machine is used as illustrated in FIG. 1 having a stationary suction box, a mask perforated with circular apertures having a diameter of 1.50 mms., these holes being arranged in rows parallel with the direction of the flexible belt, the rows being 6 mms. apart. An aqueous dispersion of 2 gms per liter of a mixture of one part of 3.3 dtex (3den) fibers of polyhexamethylene adipamide with a length of 15 mms. to one part of conventional paper pulp is prepared. The porous, endless belt is run at a speed of 2 meters per minute and a suction of 200 mms. of mercury is produced in suction device 4. After draining, pressing, and drying on heated cylinders, the sheet formed weighs g./m. and has longitudinal strips having a width of 2 mms. of a high fiber density alternating with low density strips having a width of 4 mms. The sheet produced has good resistance to tearing, is extremely even, and has a textile-like feel.
Having defined the apparatus of the present invention by way of the foregoing illustrations and example, it should be noted that the same is not to be limited thereto but is to be construed as broadly as any and all equivalents as defined in the appended claims.
What I claim is:
1. Apparatus for forming sheet material from an aqueous dispersion of fibers utilizing papermaking methods wherein the apparatus includes at least one head box, at least one suction device which is conterminous with said head box, and an endless, flexible, porous, filtering belt traveling between said head box and said suction device and forming a portion of the bottom of the head box; said suction device comprising a suction box, means for reducing the pressure within said suction box, a perforated mask and means for removably attaching said mask to said suction box; and said mask defining rows of apertures arranged parallel to the direction of travel of said filtering belt.
2. The apparatus of claim 1 including means to move said suction device in a direction transverse with respect to the direction of travel of the filtering belt.
3. The apparatus of claim 2 wherein said apertures in the mask are circular.
4. The apparatus of claim 3 wherein said rows of apertures are evenly spaced.
5. The apparatus of claim 3 wherein said rows of apertures are irregularly spaced.
6. The apparatus of claim 2 wherein said apertures are square.
7. The apparatus of claim 1 wherein said suction device is stationary.
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