US 3911281 A
An arrangement for selectively irradiating a web includes a perforate band of a radiation impermeable substance which is guided in an endless path via a pair of guide rollers and has two juxtaposed runs in this path. A take-up roller conveys a web of material past one of the runs at a side thereof remote from the other run, the direction of movement of the web being other than parallel to that of the band and, preferably, normal thereto. An electron accelerator is provided at the far side of the run remote from the web and is effective for directing a radiation beam at the web through the perforations.
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Description (OCR text may contain errors)
United States Patent Ihme Oct. 7, 1975 ARRANGEMENT FOR SELECTIVELY IRRADIATING WEBS Bernd lhme, Dresden, Germany Veb Textilkombinat Cottbus, Cottbus, Germany Filed: Feb. 12, 1974 Appl. No.1 441,877
US. Cl 250/492 A; 250/400 Int. Cl. 1101.] 3/14 Field of Search 250/400, 492 R, 492 A, 250/493, 397, 398, 399
References Cited UNITED STATES PATENTS 04 10/1959 Trump 250/492 R 45 2/1971 Petersen 2/197] Martin et al. 250/400 3,736,425 5/1973 Chemow 250/492 A Primary Examiner-James W. Lawrence Assistant ExaminerD. C. Nelms Attorney, Agent, or Firm-Michael S. Striker  ABSTRACT An arrangement for selectively irradiating a web includes a perforate band of a radiation impermeable substance which is guided in an endless path via a pair of guide rollers and has two juxtaposed runs in this path. A take-up roller conveys a web of material past one of the runs at a side thereof remote from the other run, the direction of movement of the web being other than parallel to that of the band and, preferably, normal thereto. An electron accelerator is provided at the far side of the run remote from the web and is effective for directing a radiation beam at the web through the perforations.
9 Claims, 6 Drawing Figures US. Patent OCt. 7,1975 Sheet 2 of2 3,911,281
ARRANGEMENT FOR SELECTIVELY IRRADIATING WEBS BACKGROUND OF THE INVENTION The invention relates generally to an arrangement for selectively irradiating webs, particularly textile webs. More specifically, the invention relates to an arrangement for selectively irradiating webs which is of the type wherein a template is interposed between the web and the radiation source, which latter may be an electron accelerator.
The selective irradiation of a web of material may sometimes be desirable such as, for instance, when it is desired to texturize or structurize the'material. The complete process whereby the structurizing effects are achieved is not of importance here, the important point being that there are cases where it is necessary or desirable to selectively or locally irradiate a web.
An arrangement is known with which localized or selective irradiation may be performed continuously.
Here, four guide rollers are utilized, these being mounted for rotation about axes extending normal to one another. A band is engaged by the rollers is conveyed thereby in an endless path, the band being provided with perforations which are arranged in a pattern corresponding to the pattern of selected irradiation which it is desired to achieve. The band passes beneath the scanner of an electron accelerator and a web to be irradiated is conveyed below the band so that the latter is interposed between the accelerator and the web. The band and web are conveyed in such a manner that their relative speed beneath the scanner of the electron accelerator is zero.
This prior art arrangement possesses certain disadvantages. Thus, the width of the perforated band must be equal to at least the width of the web to be irradiated. Furthermore, since four rollers are used for conveying the perforated band, the direction of movement of the latter changes four times along one complete circuit of the endless path. The large number of changes in the direction of movement of the perforated band makes it difficult to convey the same and, in addition, causes the perforated band to be highly stressed. This, in turn, results in high production costs as well as a reduction in the life of the perforated band.
SUMMARY OF THE INVENTION It is, accordingly, a general object of the invention to provide a novel arrangement for selectively irradiating webs of material. a
More particularly, it is an object of the invention to provide an arrangement for selectively irradiating webs of material whereby the irradiation and, hence, the structurizing, of the webs may be performed more economically than was possible heretofore.
Another object of the invention is to provide an arrangement for selectively irradiating webs of material wherein the width of the perforated band is independent of the width of the web to be irradiated.
A further object of the invention is to provide an arrangement for selectively irradiating webs of material wherein the perforated band is less highly stressed and has a longer life than in the prior art arrangements.
In pursuance of the above objects and of others which will become apparent, the invention provides an arrangement for selectively irradiating a web of material, particularly textiles and the like, which comprises a band of a substantially radiation impermeable substance. The band has perforations and moving means is provided for moving the band in an endless path wherein the band has two juxtaposed runs. Conveying means serves for conveying a web of material in another path which has a portion overlying one of the runs at a side of the latter remote from the other of the runs. The direction of movement of the web in the aforementioned portion of the path in which the web is conveyed defines with the direction of movement of the band in either of the runs thereof an angle greater than 0 and less than 180. lrradiating means is provided at the far'side of the run remote from the one which the web overlies, that is, at the side of this run which is furthest removed from the web, and is effective for directing a radiation beam through the perforations at the earlier mentioned portion of the path in which the web is conveyed.
The perforations in the band may be in the form of elongated slits the directions of elongation of which define an oblique angle with the direction of movement of the band in either of its runs. Preferably, this oblique angle equals about 45.
The irradiating means may be an electron accelerator although other radiation sources may also besuitable for use in an arrangement according to the invention. The moving means should move the band in such a manner that the direction of movement of the band in either of the runs thereof is opposite to that in the respective other run. Advantageously, the angledefined between the direction of movement of the web in at least that portion of its path which overlies a run of the band and the direction of movement of the latter in either of the runs is substantially that is, the directions of movement of the web and band are advantageously normal to each other. 7
The moving means may comprise a pair of spaced guide rollers engaging theband and, hence, thedirection of movement of the band along a complete circuit of its endless path need change only twice. By utilizing an arrangement in accordance with the invention, the length of the band need be only slightly greater than twice the width of the web, whereas the width of the band may correspond approximately to the effective width of the radiation beam and may be very small without, however, impairing or interrupting the periodicity or repetitiveness of the perforation pattern therein. a
It will be appreciated that, where the band is conveyed in its endless path via a pair of spaced guide rollers about each of which'its direction of movement changes, and where the perforations in tthe band are in the form of elongated slits, that the perforations in one of the runs will intersect or cross the perforations in the other run as the band moves. In order to optimize the selective or localized irradiation, it is favorable when the speeds of the web and the band are chosen so as to be substantially equal. In the event that the parameters such as the angle of inclination of the elongated slits to' the direction of movement of the band and the speeds of the web and the band deviate from the values and relationships given above, then, in order to optimize the selective irradiation, the velocity vector at the intersection of two slits in the respective runs should be selected so as to correspond in direction and magnitude to the velocity vector of the web.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view schematically illustrating an arrangement according to the invention;
FIG. 2 is a plan view of the arrangement of FIG. 1; and
FIGS. 36 illustrate different irradiation patterns which may be obtained with an arrangement according to the invention together with the configurations and distributions of the perforations used to obtain the respective patterns.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2 of the drawing, an arrangement in accordance with the invention is seen to include a band or belt 1 which, for optimum results, should be of a substantially radiation impermeable substance. A pair of spaced guide rollers 3 engages and moves the band 1 in an endless path and the direction .of movement of the band 1 is indicated by the arrow A.
The band 1 defines two juxtaposed runs 9 and 10 in its path of travel and a pair of depressing rollers 4 depresses the band 1 so that the runs 9 and 10 are in close proximity to one another. Although the runs 9 and 10 are here shown as having a substantially horizontal orientation, this need not be so. It will be appreciated that the guide rollers 3 constitute moving means for moving or conveying the band 1 in an endless path.
As best seen from FIG. 2, the band 1 is provided with perforations 7 and the latter are here illustrated as being in the form of elongated slits. The direction of elongation of the slits 7 and the direction of movement A of the band 1 define with each other an oblique angle which is preferably 45 as shown.
A web 5 of material, for example, a textile, is continuously conveyed in the direction indicted by the arrow B and a portion of the path along which the web 5 moves lies beneath the lower run 10 of the band 1. Advantageously, the direction of movement B of the web 5 is normal to the direction of movement A of the band 1 as shown although it is sufficient if the directions A and B define with each other an oblique angle greater than and less than 180. The conveying means for conveying the web in the direction B may, for instance, include a feed roller 11 and a take-up roller 12, although other suitable conveying means may be used. A suitable drive 6 may be provided for synchronizing the speeds with which the band 1 and the web 5 move along their respective paths.
An irradiating device, here illustrated as being an electron accelerator 13 provided with a scanner 2, is located above the upper run 9. Of course, other irradiating means may also be used. The accelerator 13 is effective for directing a radiation beam, in this case, an electron beam, at or towards that portion of the path of the web 5 below the lower run of the band 1.
The operation of the novel arrangement may be best understood from FIG. 2. In the position illustrated in this FIGURE the slit 7a in the upper run 9 and the slit 7b in the lower run 10 intersect or cross one another at three locations such as, for example, at the location C. It is only at such intersections that the radiation beam is able to effectively penetrate the band 1 and reach the web 5 since it is only at such intersections that an opening is defined which extends from that side of the upper run 9 at which the accelerator 13 is located to that side of the lower run 10 at which the web 5 passes thereby. As the band 1 now continues to move in the direction of the arrow A, the slit 7a will move towards the right whereas the slit 7b will move towards the left. The effect of this will be that the intersection C of the slits 7a and 7b will move towards this location C, that is, the intersection C will move in the direction of movement B of the web 5. By properly synchronizing the speeds of movement of the web 5 and the band 1, the region of the web 5 which was exposed to the radiation beam at the location C will be the same region thereof which is exposed to the radiation beam at the location C. In other words, by proper synchronization of the speeds of the web 5 and the band 1, the region of the web 5 to be irradiated will move in the direction B at the same speed as the intersection C of the slits 7a and 7b moves in this direction. Of course, the speeds of the web 5 and the band 1 should be so selected that the region of the web 5 to be irradiated will receive a sufficient radiation dose, that is, the speeds should be so selected that the dwell time in the radiation field of each region of the web 5 to be irradiated is long enough for it to absorb the desired radiation dose. The radiation pattern obtained by using the perforation pattern shown in FIG. 2 is illustrated in FIG. 3.
By varying the distance between the perforations, the number of perforations, the shapes of the perforations and the positions of the perforations, different radiation patterns may be obtained. FIGS. 46 illustrate a few of the diverse radiation patterns which may be obtained in accordance with the invention and, in each case, the shape and distribution of the perforations used to obtain the corresponding radiation pattern is also shown. 7
It will be apparent that the novel arrangement is very versatile and that any desired radiation pattern may be obtained by interchanging the relatively small band 1. It is, therefore, understood that the embodiment described above in detail is only exemplary of the invention and is not intended to limit the latter in any manner.
One of the many applications for which the invention may be used resides in the structuring of materials. In the following Example, which is to be considered as exemplary only and not as limiting the invention in any way, a process for structuring materials will be described:
EXAMPLE An arrangement for conveying a band in an endless path, corresponding to that shown in FIGS. 1 and 2,
and having a length of 2.75 meters and a width of 0.5
meters, is provided beneath the scanner .of an electron accelerator. The scanner has a width of 2.5 meters and the electron accelerator has a power output of 1 MeV and generates an electron beam having a radiation intensity of 4.10 rad/sec. A band having a perforation pattern corresponding to that of FIG. 3 is provided and has a length of 6 meters and an effective width of 0.30
meters. An unpatterned polyamide mesh is conveyed beneath the band in the manner of FIGS. 1 and 2. The polyamide mesh has a width of 2 meters and a mass per unit area of 150 g/m. The polyamide mesh is conveyed beneath the band at a speed of m/min and the speed of the band in its endless path is also 10 m/min. The selectively or locally irradiated regions of the polyamide mesh such as the regions shown in FIG. 3 absorb a radiation dose of 7.210 rad. Subsequent to the irradiation, the polyamide mesh is treated with acrylic acid and graft polymerization of the latter and the polyamide mesh occurs. As a result, the graft polymerized locally irradiated regions of the polyamide mesh shrink and, consequently, structuring of the polyamide mesh is obtained and a patterning effect is visible.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of construction and uses differing from the types described above.
While the invention has been illustrated and described as embodied in an arrangement for selectively irradiating webs, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:
1. An arrangement for selectively irradiating webs of material, particularly textiles and the like, comprising a band which is substantially impermeable to radiation having an energy less than a predetermined value, said band being provided with perforations so as to permit the passage therethrough of radiation having an energy less than said predetermined value; moving means for moving said band in an endless path wherein said band has two juxtaposed runs; conveying means for conveying a web of material in another path having a portion which. extends across one of said runs at a side of the latter which faces away from the other of said runs, said conveying means being arranged so that the direction of movement of said web in said portion defines with the direction of movement of said band in either of said runs an angle greater than 0 and less than 180; and irradiating means at a side of said other run which faces away from said one run and being adapted to direct a beam of radiation having an energy less than said predetermined value through said perforations at said portion.
2. An arrangement as defined in claim 1, wherein said perforations comprise elongated slits the directions of elongation of which define with the direction of movement of said band in either of said runs an oblique angle.
3. An arrangement as defined in claim 2, wherein said oblique angle is substantially 45.
4. An arrangement as defined in claim 1, wherein said angle is substantially 5. An arrangement as defined in claim 1, wherein said angle is an oblique angle.
6. An arrangement as defined in claim 1, wherein said runs have a substantially horizontal orientation.
7. An arrangement as defined in claim 1, wherein said moving means comprises a pair of spaced rollers engaging said band.
8. An arrangement as defined in claim 1; and further comprising synchronizing means for synchronizing the speeds of said band and said web.
9. An arrangement as defined in claim 1, wherein said irradiating means comprises an electron acceleratOI'.