US3234040A - Cigarette machine tapes - Google Patents

Description

United States Patent 3,234,040 CIGARETTE MACHINE TAPES John James Kirwan, Hillside, England, assignor, by mesne assignments, to Brown and Williamson Tobacco Corporation, Lonisville, Ky., a corporation of Delaware Ne Drawing. Filed July 13, 1961, Ser. No. 124,312 Claims priority, application Great Britain, July 15, 1969, 24,7 69/ 60 1 Claim. (Cl. 117-76) This invention concerns improvements relating to cigarette-machine tapes, that is the conveyor tapes employed in cigarette-making machines. These tapes, which are usually endless woven tapes with cotton weft and linen-fibre warp, commonly travel through the pressure unit, tongue piece and garniture at about 275 feet per minute. The tape is subject to heat and friction in the garniture and also to an alternating flexing action. In addition, some of the ink from the printing on the cigarette paper offsets on to the upper face of the tape and causes the fibres to rot. As a result, the working life of such tape is very short. In addition, the pressure of the tape against the paper tends to produce so-called tape marks, i.e. a more or less pronounced embossed weave appearance. The present invention accordingly seeks to improve the working life of the tape and to reduce tape marks on the cigarettes.

According to the invention, cigarette-machine tape is first treated with an application of microcrystalline wax for lubricating its internal fibres and is then given an external coating of a lacquer. By using this combination of media, a considerably improved working life, for example a three-fold increase can be obtained without it being necessary to employ an excessive amount of wax, such as would involve risk of wax-staining of the cigarettes in passing through the hot garniture. At the same time, the rotting effect of the drying ink from the cigarette print is resisted by the lacquer. The latter is preferably a solution of a copolymer of vinyl chloride/ acetate resin, which has been found to possess very good resistance to wear and to ink, but other synthetic resin or nitro cellulose lacquers may be employed.

A preferred manner of carrying the invention into effect will now be more fully described.

The cigarette-machine tapes are first immersed in a solution of a microcrystalline wax in a volatile solvent for the wax, preferably carbon tetrachloride, using 5 g. of a microcrystalline wax in 100 g. of solution from which the tapes absorb approximately /2 to 1 g., depending on the size of the tape treated. For this purpose, the tapes are placed in baskets and lowered, in a fume cabinet, into the solution, held at a temperature of 120 F., for a period of say, four minutes. During immersion, the window of the cabinet is closed and an extractor assists in removing fumes rising from the solvent. When the tapes are removed from the solution, they are laid on a draining board within the cabinet for a few 3,234,941 Patented Feb. 8, 1966 minutes. As the carbon tetrachloride evaporates, the tapes become whiter and the operator can judge by the degree of whiteness when they can be taken from the cabinet and hang on racks to dry by airing overnight.

On the following day, the tapes are coated on one side with the coating material which is evenly distributed thereon.

When the tapes have been coated on one side, they are dried. This may be effected by hanging them on hooks 1 of the revoluble carrier of a drying machine. After the tapes have been thus dried, each tape is turned and the uncoated side is then coated and dried in the drying chamber in the manner described above. On their second removal from the drying chamber, the tapes are hung on stands overnight.

The present invention contemplates coating two tapes at a time as well as coating tapes which are of various lengths.

The coating material, producing a lacquer-like coating, is preferably a copolymer of vinyl chloride/ acetate resin dissolved in a solvent comprising a ketone or a mixture containing a ketone or ketones, for example a mixture of acetone and toluene. One suitable such solution coating by way of example may comprise 90% by weight of vinyl chloride and of vinyl acetate in a ketone solution having an intrinsic viscosity of 0.79 and a specific gravity of 1.36. However, other similar vinyl chloride/ acetate solution coatings may be employed.

After being hung overnight or, say, for 24 hours, to remove all traces of solvent, the tapes are calendered and dried. This invention contemplates calendering and drying two sets of tapes as well as tapes of different lengths.

I claim:

An improved cigarette machine tape having wear and abrasion resistance properties comprising a narrow endless woven fabric tape constituting a cigarette machine tape of predetermined length and having fibers, said fibers having microcrystalline wax impregnated thereon for lubricating the fibers to reduce wear of the tape caused by the flexing of the tape fibers in the cigarette machine, and an external layer of lacquer of a copolymer of vinyl chloride/ vinyl acetate resin on both sides of the tape for providing a protective layer for said wax and said fibers. 45

References Cited by the Examiner UNITED STATES PATENTS 2,184,600 12/1939 Knup et al. 11776 2,227,787 1/1941 'Laufer 11792 2,306,046 12/1942 Duggan et al. '11792 X 2,800,701 7/1957 Watts et al. 74232 3,023,482 3/1962 Gilboy et al. 11776 X WILLIAM D. MARTIN, Primary Examiner.

JOSEPH B. SPENCER, RICHARD D. NEVIUS,

Examiners.