US3127303A

US3127303A - wilson

Info

Publication number: US3127303A
Authority: US
Publication date: 1964-03-31
Anticipated expiration: 1981-03-31

Description

March 1964 w. J. NEUHAUSER ETAL 7,

DUAL-ADHESIVE SPLICING SYSTEM Filed Feb. 10, 1960 ifil llllllllllllz INVENTORS. WILL/AM J. NEUHAUSER CALVIN L. WILSON EARL M T/LLER WQW United States Patent 3,127,303 DUAL-ADHESIVE SPLICING SYSTEM William J. Neuhauser, Jefferson County, Calvin L. Wilson, Louisville, and Earl M. Tiller, Jefferson County, Ky., assignors to Reynolds Metals Company, Richmond,

Va., a corporation of Delaware Filed Feb. 10, 1960, Ser. No. 7,802 6 Claims. (Cl. 161-39) This invention relates to splicing foil, and particularly aluminum foil strip which is subsequently wound on to a roll and annealed before being laminated and printed.

Foil strip occasionally breaks during the rolling operations, and it is then conventional to trim the broken ends and splice them together in abutting relation by application of adherent tape to one or both sides of the break, before resuming operations. A conventional splicing tape is a ribbon of aluminum foil with adhesive on one side to grip the spliced ends of the foil strip. The roll of foil containing the splice is then usually annealed at temperatures of about 500 to 800 F., and after annealing the roll of foil is unwound preliminary to further operations, such as converting or laminating. For this reason, an adhesive is required which will not lose its holding quality in that temperature range.

Difficulty, including further breakage, is often encountered when the annealed roll is unwound, because of adhesion between the spliced joints and the surfaces of adjacent convolutions of the foil. Although the foil tape is impervious to penetration by the adhesive, pressure sometimes causes the adhesive on the tape to bleed beyond the edges of the tape when the spliced strip is wound in a roll, and this small amount of adhesive is enough to stick to adjacent convolutions of the foil strip, causing the foil strip to break when the roll is unwound after the annealing operation. It is conventional to dust the spliced strip with talc in order to minimize such unwanted sticking, but this is not always effective, and the tendency of the talc to spread as much as two or three feet from the spliced joint increases the amount of scrap which must eventually be discarded when the spliced joint is cut away during final inspection.

While various heat-activated adhesives have been tried for this purpose, certain problems have developed. When wide strips are spliced, the adhesive necessarily extends over a substantial area. It was found to be very difficult to apply heat evenly over such area without producing wrinkles, and subsequent interference with winding and unwinding operations.

In addition, adhesives having desired thermal properties were found frequently to lack sufiicient tackiness at room temperature to retain their placement prior to the application of heat and pressure.

In accordance with the present invention, these problems are minimized or eliminated by a novel splicing tape which employs a duality of adhesive materials. One material, which is tacky and effective without the application of heat or great pressure, is disposed in a narrow band centrally of the tape. A second material, requiring pressure and/ or heat to develop its adhesive quality, is disposed in spaced narrow bands which straddle the first material. By this combination, the tape is held securely in place initially by the first adhesive. The subsequent application of heat from the annealing operation functions to set up the second material, providing a permanent bond, and establishing barriers effective to preclude bleeding out of the first adhesive. The result is a splice free from wrinkles, due to the lesser areas of heat-sensitive adhesive; and the previously required talc dusting step becomes unnecessary.

For better understanding of the invention, reference is made to the accompanying drawing, in which there is shown, for puropses of illustration only, a present preferred embodiment of the invention.

In the drawing:

FIG. 1 is a semi-diagrammatic longitudinal plan view of a strip of foil having a taped splice;

FIG. 2 is an enlarged cross-sectional view of the spliced portion of the strip, taken on line 22 of FIG. 1; and

FIG. 3 is a fragmentary plan view of the adhesive side of a tape in accordance with the present invention.

Referring now to the drawing, a strip 10 of aluminum foil (FIG. 1) is customarily rolled in sizes of up to about 60 inches in Width and varying in thickness from 0.00025 inch to 0.001 inch, and wound into a large roll, which is then annealed preparatory to slitting, laminating, printing and other operations. The strip is sometimes torn across its width during rolling, and the torn ends are rejoined by a splice. As shown in FIG. 1, the strip 10 is severed along the line 12 where the trimmed ends are abutted and secured together by splicing tapes 14. After splicing, the rolling and winding of the strip 10 on the roll is completed. The length of the tape 14 is approximately the same as the width of strip being spliced, although it may be made greater, to facilitate subsequent inspection of the roll and cutting out of the spliced joint where that is desired.

Two of the tapes 14 are preferably applied on opposite sides of the foil strip, as shown in FIG. 2. Each of the tapes 14 comprises a ribbon of foil 16, for example, aluminum foil of 0.00035 inch thickness, and adhesive disposed on one side of the foil ribbon. For purposes of illustration, FIG. 2 shows the adhesive layers with greatly exaggerated thickness.

As shown in FIGURE 3, a central band 18 of tacky adhesive is applied to the foil ribbon 16. For this purpose, a material such as Dow Corning #269 has been found suitable. On either side of band 18 are similar bands 20 of another adhesive, preferably Dow Corning Silicone #993.

The band 18 serves to hold the tape 14 in place, and to temporarily splice the strip.

After the foil strip has been wound into a roll with the spliced joint within the convolutions of the roll, the roll is deposited in an annealing oven. When heat is subsequently applied, the outer bands 20 are activated to complete a permanent seal and confine the adhesive of band 18 (which may flow at the temperature level of the annealing furnace). The annealed roll is subsequently unwound for use or further processing, such as laminating to backing paper and then printing. It has been found that, by use of the special tape 14, the splice or joint does not bleed adhesive; and consequent sticking to adjacent convolutions of foil is thereby avoided when the roll is unwound.

While the present preferred embodiment and method of practicing the invention has been described and illustrated, it will be recognized that the invention may be otherwise variously embodied and practiced within the scope of the following claims.

We claim:

1. A tape for use in splicing metal foil strip comprising a layer of foil, a coating of adhesive which is tacky at room temperature disposed centrally on said foil layer and extending lengthwise of the tape, and spaced bands of a second adhesive on said layer of foil at either side of said central coating, said second adhesive being heatresponsive in the range of temperatures utilized for annealing the foil strip to form a strong bond between said tape and the foil strip being spliced.

2. A foil strip having a splice, said splice comprising separated edges transversely of a foil strip juxtaposed in substantially abutting relation, and at least one splicing tape extending along and overlapping said edges and adhering to one side of the foil strip, said tape including a layer of foil having a plurality of adhesive substances disposed thereon in generally parallel spaced bands, at least one centrally disposed band comprising an adhesive which is tacky at room temperature, and the outermost bands adjacent the longitudinal edges of said layer of foil comprising adhesive substances which are thermosetting.

3. A spliced foil strip according to claim 2 wherein said foil layer is aluminum foil and the thermosetting adhesive bands of the tape are heat-responsive in the range of temperatures for annealing said foil to complete the bond between said tape and said foil strip, whereby said outermost bands establish barriers against the flow of said tacky adhesive beyond the edges of said layer of foil and upon the surface of said foil strip.

4. In the art of splicing a strip of metal foil, including the steps of trimming the edges of a tear in the foil, abutting the trimmed edges and applying a splicing tape to the foil strip, the improvement which comprises initially adhering said tape to the foil with pressure sensitive adhesive which is tacky at room temperature, providing bands of thermosetting adhesive between said firstmentioned adhesive and the foil surfaces adjacent the tape, and heating the strip to activate said thermosetting adhesive and thereby to prevent the flow of said firstmentioned adhesive onto the adjacent exposed surfaces of the foil.

5. The method of joining strips of aluminum foil disposed in substantially abutting relationship comprising the steps of applying a splicing tape on opposite sides of the foil overlapping the opposed ends of said strips, initially adhering said tape to the foil by means of a narrow band of pressure sensitive adhesive which is tacky at room temperature but tends to flow at a temperature suflicient to anneal the foil, and preventing said adhesive from flowing onto the exposed surfaces of the foil strips by disposing spaced bands of thermosetting adhesive straddling said narrow band of adhesive and heating the strips to anneal the foil and to establish the holding action of the thermosetting adhesive.

6. The method of splicing aluminum foil in strip form preparatory to the annealing of said foil, comprising the steps of trimming the edges of a tear in the foil, juxtaposing the trimmed edges in substantially abutting relationship, initially adhering to the foil an aluminum foil splicing tape on at least one side of the strip and overlapping the trimmed edges employing an adhesive which is tacky at room temperature, preventing the flow of said adhesive onto the exposed foil surfaces during subsequent annealing by providing barrier layers of thermosetting adhesive between said first-mentioned adhesive and the edges of said tape adjacent said surfaces, and annealing the foil in the form of a tightly wound coil, the annealing temperature being sufficient to establish the holding action of said thermosetting adhesive and the barrier layers thereby preventing sticking between adjacent layers of the coil.

References Cited in the file of this patent UNITED STATES PATENTS 693,5 14 Haberstroh Feb. 18, 1902 852,761 Bodine May 7, 1907 1,217,252 VJilliarnson Feb. 27, 1917 2,372,737 Phillips Apr. 3, 1945 2,711,382 Smith-Johannsen June 21, 1955 2,975,091 Tobey Mar. 14, 1961

Claims

1. A TAPE FOR USE IN SPLICING METAL FOIL STRIP COMPRISING A LAYER OF FOIL, A COATING OF ADHESIVE WHICH IS TACKY AT ROOM TEMPERATURE DISPOSED CENTRALLY ON SAID FOIL LAYER AND EXTENDING LENGTHWISE OF THE TAPE, AND SPACED HANDS OF A SECOND ADHESIVE ON SAID LAYER OF FOIL AT EITHER SIDE OF SAID CENTRAL COATING, SAID SECOND ADHESIVE BEING HEATRESPONSIVE IN THE RANGE OF TEMPERATURES UTILIZED FOR ANNEALING THE FOIL STRIP TO FORM A STRONG BOND BETWEEN SAID TAPE AND THE FOIL STRIP BEING SPLICED.