US 3012562 A
Description (OCR text may contain errors)
Dec. 12, 1961 -H. B. MERRITT 3,012,562
MANUFACTURE OF TOBACCO SHEET Filed June 12, 1957 GRIND GRIND TOBACCO ADHESIVE MIX GROUND TOBACCO AND ADHESIVE MELT ADHESIVE FORM SHEET HARDEN ADHESIVE CUT SHEET TO SIZE INVENTOR HENRY B. MERRITT ATTOR Y United States Patent 9 3,012,562 MANUFACTURE F TOBACCO SHEET Henry B. Merritt, Mamaroneek, N.Y., assignor to American Machine & Foundry Company, a corporation of New Jersey Filed June 12, 1957, Ser. No. 665,160 5 Claims. (Cl. 131140) This invention relates to the manufacture of tobacco sheet. In particular the invention relates to a random mixture of a major part of finely divided tobacco and a minor part of thermoplastic adhesive.
Many proposals have been made for making tobacco sheet from finely divided tobacco. All of these methods have relied upon the treatment of an adhesive material with a solvent or liquid dispersing material which is removed by evaporation from the tobacco sheet. Usually this material has been Water, but organic solvents have also been suggested for use with thermoplastics such as cellulose acetate. Such liquid materials tend to harm the tobacco aroma or increase the cost of manufacture.
Heretofore mixtures of tobacco and adhesive have been dry mixed and formed into a sheet with the addition of moisture. However, all of these sheets have been easily disrupted by excess water and have required elaborate evaporation procedures in order to adjust moisture content.
Therefore, it is an object of this invention to provide a method of forming tobacco sheet from a thermally softened adhesive, preferably without the use of liquids.
Another object of the invention is to provide a tobacco sheet which includes finely divided tobacco and a thermally softened adhesive material.
These and other objects are described more particularly in the following account of the invention taken together with the accompanying drawing which shows a box type schematic flow sheet of a method of making tobacco sheet according to the invention.
According to a preferred form of the invention as shown in the drawing, a minor proportion of thermoplastic adhesive powder is mixed with a major propor tion of finely divided tobacco, preferably although not necessarily in the absence of liquid, and the mixture is heated to soften or fuse the plastic. The mix is formed into a sheet, cooled and cut to size. Fibers, fillers and plasticizers may be added to the dry mix before the sheet is formed.
Heating of the plastic adhesive is advantageously done by dielectric heating although convection heating with hot gas is also useful. When dielectric heating is used, the moisture content of the tobacco is preferably about 25%. Heated rollers are also useful in forming the tobacco sheet.
Generally a very thin sheet is formed. A sheet between one and ten mils is useful but about four mils is preferable.
The adhesive may be cured and hardened, as by an included catalyst, or refrigeration, and after a brushing to remove loose tobacco material, which may be reused, the sheet is rolled and cut to appropriate size.
The sheet is suitable for use in smoking articles such a cigars and cigarettes, both as shredded filler and as binder or wrapper.
The preferred adhesive for use with tobacco in this invention is cellulosic and particularly ethyl cellulose. Various cellulose base esters and mixtures and copolymers thereof are also equally suitable. These include acetate, propionate and butyrate of cellulose.
Alkyl cellulose others such as ethyl cellulose are suitable, particularly when 50% or more of the hydroxyl radicals of cellulose have been replaced by alkoxy groups.
Non-cellulosic thermoplastic polymers such as olefins of the polyethylene type and polyamides of the nylon type as well as vinyl and vinylidene resins such as polyvinyl alcohol are also suitable. Waxes may also be used. All of the adhesives may incorporate conventional plasticizers.
Although some of the non-cellulosic materials burn poorly, they are used in relatively small amounts and may be combined with conventional burn catalysts so that the sheet will, nevertheless, burn Well and undesirable odor is masked by the preponderant quantity of tobacco which is preferably over by weight.
The following example illustrates the invention in a preferred form:
Example About grams of dry ethyl cellulose powder of about 50% ethoxy content and of about 150 US. standard mesh size is mixed with about 1000 grams of dry ground tobacco of similar size and of about 20% moisture content on a dry weight basis. The mixed powders are heated to about C. in an oven until an even temperature prevails throughout the mass and the plastic polymer has become very soft. The hot dough-like mixture is squeezed through a series of hot rollers until a sheet about six mils thick is made. This sheet is then run through cold rollers and the resulting sheet is cut to useful size for shredding into a cigarette blend. This is shown in the drawing.
What is claimed is: p
1. A method of making tobacco sheet comprising in combination the steps of combining a major proportion by Weight of finely divided tobacco and a minor proportion by weight of thermoplastic adhesive, applying heat to the tobacco and adhesive and forming the combination of tobacco and adhesive into a sheet.
2. A method of making tobacco sheet comprising in combination the steps of mixing finely divided tobacco with finely divided thermoplastic adhesive to form an intimate mixture, heating said plastic adhesive to soften the same, adhering tobacco thereto, extruding said mixture as a tobacco sheet and hardening said plastic.
3. A method of making a tobacco product comprising heating a thermoplastic material until it is soft and adhesive, adhering finely divided tobacco thereto and thereafter cooling said adhesive material.
4. A method of making a tobacco product comprising shaping a mixture of finely divided tobacco and a thermally softened adhesive while said adhesive is soft and thereafter allowing said adhesive to cool.
5. Amethod of making a tobacco sheet comprising in combination the steps of combining a major-proportion by Weight of finely divided tobacco and a minor proportion by weight of thermoplastic adhesive rendered soft by heat, forming the composition of tobacco and hot, soft adhesive into a sheet and thereafter cooling said sheet.
References Cited in the file of this patent UNITED STATES PATENTS 61,275 Stayman Jan. 15, 1867 5, 64 Grunauer Feb. 16, 1932 4 ,549 Edmonds Jan. 10, 1939 9,975 Moseley et a1. Feb. 2, 1943 .4 .877 Wells et al Jan. 6, 1948 ,483,418 Kamlet Oct. 4, 1949 70 Sowa et a1. Oct. 25, 1949' 75 Samfield et a1. May 10, 1955 83. Frankenburget a1. May 29, 1956