US2876893A - Adhesive tape with convolutions tensioned under predetermined program - Google Patents

Description

March 10, 1959 ADHESIVE TAPE WITH CONVOLUTIONS TENSIONED UNDER PREDETERMINED-PROGRAM B. B. BLACKFORD EI'AL 2,876,893

Filed Aug. 30, 1954 v so 5 6 4. 2 o

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WQTTZ RNEY ADHESIVE TAPE Vtli'i-i CGNVOLUTIONS TEN- SIONED UNDER PREDETERMINED PROGRAM Benjamin B. Blackford, Metuchen, and George W. McLaren, Jr., New Brunswick, N. 3., assignors to Johnson & Johnson, a corporation of New Jersey Application August 30, 1954, Serial No. 452,996

8 Claims. (Cl. 20659) This invention relates to normally tacky pressure sensitive adhesive tape and particularly to rolls thereof processed to facilitate their unwinding especially near the core.

it is conventional to wind surgical plaster, by way of example, that type having cloth backing coated with normally tacky pressure sensitive adhesive mass, by application of constant torque upon a winding mandrel to produce a roll of tape whose tension is greatest adjacent the axis about which it is wound.

When the winding tension in a conventional roll of tape is such as to provide in the outer convolutions a firmness suflicient to resist deformation under normal handling, it has been found that the tension in the inner convolutions, in many cases, is so great as tocause flow of the adhesive, its transfer to the back of adjacent convolutions, and such extreme difiiculty in unwinding as practically to render useless a relatively large section of the roll.

It has been discovered that if adhesive plaster with uncoated cloth backing is wound under tension below that which will cause flow of the adhesive mass through the cloth, such winding tension even after aging will remain in the roll as an unwinding pattern, and that if a Winding program is employed characterized by the use of low tension in the inner convolutions and higher tension in the outer convolutions, a roll of tape results having a firm exterior resistant to deformation and yet capable of being unwound with the utmost ease down even to the very end. Indeed what is most surprising is that a roll of tape with such an unwinding pattern is easier to unwind as it approaches the inner end of the tape than it is at the outer end.

Other advantages of the improved roll of tape will be apparent from thefollowing description in conjunction with the accompanying drawings wherein:

Fig. 1 illustrates a rollof pressure sensitive adhesive tape having outer convolutions wound with greater tension than its inner convolutions; and

Fig. 2 is a chart in which unwinding tension in the tape is plotted against yards of tape on the core.

In Fig. 1 there is illustrated a roll of surgical plaster 1t) wound upon a core 11 and which includes a backing 12, preferably cloth, having one surface coated with a layer of normally tacky pressure sensitive adhesive 13.

In manufacturing such a roll of tape conventional methods may be followed up to and including the slitting operation, but when the tape is wound into rolls of appropriate length and width, a winding torque is exerted on the mandrel on which the tape cores are placed, which is varied according to a pro-gram predetermined for the roll of tape throughout its entire length, the predetermined program preferably being such that the tension applied to the tape during the winding operation increases from the core outwardly. By programing the winding, normally tacky pressure sensitive adhesive tape whose backing and adhesive coating are such that wind-up tenatcnt sion can determine the unwind pattern of the tape, all the characteristics that experience shows desirable in a roll of tape may be realized.

In selecting characteristics most desirable in a roll of tape, consideration should be given to the facility with which it may be unwound, its appearance, and its resistance to deformation during handling. Seemingly the most desirable unwinding pattern would be one in which there is no adhesion to the underlying convolution at all, but that obviously is quite out of the question with pressure sensitive adhesive tape. The optimum tension employed is that which will give greatest ease in unwinding consistent with an absence of openings between convolutions and a firmness at the exterior sulficient to preserve a good appearance and permit handling without undue deformation.

In accordance with the invention the roll of tape preferably should unwind in an average pattern corresponding to a steady decrease in unwinding tension as the roll is unwound. Characteristics of such rolls of tape are illustrated by way of example in Fig. 2. The tape there represented had a backing of x 80 woven cloth and a coating of pressure sensitive adhesive 5 ozs. to the square yard. The preferred unwinding pattern is represented by curve a denoting a roll-of tape which in its outer convolution has a tension of approximately 7 ozs. per inch of width and gradually falls off to approximately 4V2 02s. per inch of width near the core. The unwinding tension may go as high as 8 ozs. per inch of width in the outer convoluition and falling off to approximately 5 /2 ozs. at the core, as illustrated in curve 12. While curve b was arbitrarily selected as the upper limit of the tension program for a commercial product for a given service, and which has curve a as the norm, quite obviously a higher tension program maybese'lected as the upper limit if desired. The lower limit for the particular product referred to may be represented by the curve 0. This curve however should not be regarded quantitatively since it merely represents for the particular tape in question those tensions where it is expected spaces will appear between convolutions. Obviously here too, tapes whose unwinding program involves tension of a lower value, could be wound in accordance with the invention so long as no spaces develop between convolutions, since such rolls would be unsatisfactory from a commercial standpoint. Sudden shifts in the tension level during winding are apt to induce openings between convolutions during aging and accordingly should be avoided.

It is thought that the upper tension limit for any given tape may be fixed at that where the adhesive will start to flow and the mass transfer. The lower limit would be that tension below which spaces would start to appear between convolutions.

The method or apparatus used fonwinding tape in accordance with the invention is not important so long as the resulting rolls of tape throughout their length have the unwinding tension characteristics of the predetermined program. The efficacy of any particular unwinding program may be quickly checked, however, by Winding up say a ten-yard length of tape with the desired tension pattern obtained by the application at the end of the tape and throughout the wind of a weight appropriately varied to produce such pattern.

The tape may be wound by hand, varying the winding tension in accordance with the desired program, or may be wound by winding apparatus especially designed to give the desired winding program. A machine designed to wind tape with an increasing winding tension well suited for winding rolls of adhesive tape in accordance with the present invention is described and claimed in the co-pending application of Stanley C. Larson and John 3 J. Halliday, Serial No. 472,938, filed December 3, 1954.

The invention has been illustrated in connection with one embodiment thereof although many modifications are within its spirit. It is to be limited therefore only by the scope of the appended claims.

What is claimed is:

1. A roll of normally tacky and pressure sensitive adhesive tape with adjacent convolutions in face-to-face contact and including a woven cloth backing having on one side, a pressure sensitive adhesive coating and, on the other side, an absence of any coating that would tend substantially to alter the discontinuity normally presented by such a cloth backing by virtue of its weave, said roll of tape between the adhesive coated sides of the respective convolutions and the sides of the convolutions in face-to-face contact therewith having adhesive engagement of varying degree, said degree of adhesive engagement increasing from the core outwardly throughout the roll in accordance with a predetermined pattern, said pattern of adhesive engagement requiring, in the unwinding of the roll, a tension to effect adhesive disengagement between the respective convolutions which is less for the convolutions near the inner part of the roll than for those near the outer part of the roll.

2. A roll of normally tacky and pressure sensitive adhesive tape with adjacent convolutions in face-to-face contact and including a Woven cloth backing having on one side, a pressure sensitive adhesive coating and, on the other side, an absence of any coating that would tend substantially to alter the discontinuity normally presented by such a cloth backing by virtue of its weave, said roll of tape between the adhesive coated sides of the respective convolutions and the sides of the convolutions in face-to-face contact therewith having adhesive engagement of varying degree, said degree of adhesive engagement increasing from the core outwardly throughout the roll in accordance with a predetermined pattern, said pattern of adhesive engagement requiring, in the unwinding of the roll, a tension to efiect adhesive disengagement between the respective convolutions which is less for the convolutions near the inner part of the roll than for those near the outer part of the roll, and said convolutions near the outer part of the roll being such as to impart substantial resistance to deformation of the roll under normal handling.

3. A roll of normally tacky and pressure sensitive adhesive tape with adjacent convolutions in face-to-face contact and including a woven cloth backing having on one side, a pressure sensitive adhesive coating and, on the other side, an absence of any coating that would tend substantially to alter the discontinuity normally presented by such a cloth backing by virtue of its weave, said roll of tape between the adhesive coated sides of the respective convolutions and the sides of the convolutions in face-to-face contact therewith having adhesive engagement of varying degree, said degree of adhesive engagement increasing from the core outwardly throughout the roll in accordance with a predetermined pattern, said 4 pattern of adhesive engagement requiring, in the unwinding of the roll, a tension to effect adhesive disengagement between the respective convolutions which decreases substantially uniformly from the outer to the inner ends of the tape in the roll.

4. A roll of normally tacky and pressure sensitive adhesive tape with adjacent convolutions in face-to-face contact and including a woven cloth backing having on one side, a pressure sensitive adhesive coating and, on the other side, an absence of any coating that would tend substantially to alter the discontinuity normally presented by such a cloth backing by virtue of its weave, said roll of tape between the adhesive coated sides of the respective convolutions and the sides of the convolutions in face-to-face contact therewith having adhesive engagement of varying degree, said degree of adhesive engagement increasing from the core outwardly throughout the roll in accordance with a predetermined pattern, said pattern of adhesive engagement requiring, in the unwinding of the roll, a tension to effect adhesive disengagement between the respective convolutions which is less for the convlutions near the inner part of the roll than for those near the outer part of the roll, said convolutions near the outer part of the roll being such as to impart substantial resistance to deformation of the roll under normal handling and said roll throughout being devoid of spacing between convolutions.

5. A roll of pressure-sensitive adhesive-coated fabricbacked tape having unwinding tensions no greater near the core than throughout the rest of the roll, the exterior convolutions of said roll being firmer and more resistant to deformation than the interior convolutions of said roll.

6. A roll of pressure-sensitive adhesive cloth-backed tape having an unwinding tension which is less near the core than toward the outer periphery of said roll, the exterior convolutions of said roll being more resistant to deformation than the interior convolutions of said roll.

7. A roll of pressure-sensitive adhesive tape in accordance with claim 6 wherein the unwinding tension decreases substantially uniformly from the exterior convolutions of the roll toward the interior convolutions thereof.

8. A roll of pressure-sensitive adhesive-coated fabric tape wherein the outer convolutions of said roll are firmer than the inner convolutions of said roll, the outer convolutions being more compressed than the inner convolutions particularly near its core.

References Cited in the tile of this patent UNITED STATES PATENTS 2,349,710 Evans May 23, 1944 2,350,369 Sampair et al. June 6, 1944 2,372,336 Olsen Mar. 27, 1945 2,680,573 Monkley June 8, 1954 2,702,772 Pronio ...e Feb. 22, 1955

Claims (1)

1. A ROLL OF NORMALLY TACKY AND PRESSURE SENSITIVE ADHESIVE TAPE WITH ADJACENT CONVOLUTIONS IN FACE-TO-FACE CONTACT AND INCLUDING A WOVEN CLOTH BACKING HAVING ON ONE SIDE, A PRESSURE SENSITIVE ADHESIVE COATING AND, ON THE OTHER SIDE,AN ABSENCE OF ANY COATING THAT WOULD TEND SUBSTANTIALLY TO ALTER THE DISCONTINUITY NORMALLY PRESENTED BY SUCH A CLOTH BACKING BY VIRTUE OF ITS WEAVE, SAID ROLL OF TAPE BETWEEN THE ADHESIVE COATED SIDES OF THE RESPECTIVE CONVOLUTIONS AND THE SIDES OF THE CONVOLUTIONS IN FACE-TO-FACE CONTACT THERWITH HAVING ADHESIVE ENGAGEMENT OF VARYING DEGREE, SAID DEGREE OF ADHESIVE ENGAGEMENT INCREASING FROM THE CORE OUTWARDLY THROUGHOUT THE ROLL IN ACCORDANCE WITH A PREDETERMINED PATTERN, SAID PATTERN OF ADHESIVE ENGAGEMENT REQUIRING, IN THE UNWINDING OF THE ROLL, A TENSION TO EFFECT ADHESIVE DISENGAGEMENT BETWEEN THE RESPECTIVE CONVOLUTIONS WHICH IS LESS FOR THE CONVOLUTIONS NEAR THE INNER PART OF THE ROLL THAN FOR THOSE NEAR THE OUTER PART OF THE ROLL.

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