IL32164A - Cigarette wrapper - Google Patents

Description

CIGARETTE WRAPPER CIGARETTE WRAPPER This disclosure relates to a cigarette wrapper and method of making the same. It has been known that the amount of smoke delivered to the smoker of a cigarette oan be lowered, without increasing the reslatance-to-draw of the cigarette, by increasing the proportion of air which is drawn in with the smfcke behind the burning coal. It is also known that additional air can be provdied with the smoke by using a very porous paper as the . wrapper for the tobacco or by placing perforations in the paper. In this way a greater proportion of the combustion products are dissipated to the atmosphere in the intervals betweer ~~iffing. Cigarettes have also been made wherein ventilation J— ae have been included in the paper or in the overtipping surrounding the filter plug of a filter cigarette. In addition, various n methods have been described for the smoker to select the degree of ventilation before smoking.

None of the above-described methods has been completely satisfactory, however. Cigarette which have been ventilated to any significant degree have been characterized by many smokers as being "thin", "tasteless", or "not satisfying".

An invention which involves reducing the amount of smoke delivered by a cigarette to the smoker is set forth in United States patent 2,992,6^7 to Frank H. J, Figge, The Figge patent involves a method of making a combustible oigarette or the like having built-in means for regulating the combustion temperature, said means comprising perforations or pores in the cigarette paper which are filled with a material that melts or sublimes at such a temperature that the perforations or openings vill open up a short distance in advance of the burning area to regulate the amount of air or the percentage of the puff coming through the burning area,. While the Figge patent provides advantages over the prvlouely known ventilation means, it does not provide a complete solution to the basio^ problem, which includes a combination of (l) reducing the amount of smoke delivered to the smoker of a cigarette, and (2) satisfying the smoker of the cigarette.

The Figge invention, however, while providing an automatic method for opening vent holes in cigarettes, involves .an . opening . of the vent holes upon the approach of the hot coal to the vent holes , The present invention provides an improvement over Figge in * that the holes are more readily opened and at a farther distance from the coal in the present invention than can be achieved by Figge. While we do not wish to be bound by any theory, it is our ■ belief that this is due to the fact that the water-soluble materials used in the present invention are more easily broken down due to ,1· moisture in the tobacco smoke than the materials of i ge which . are broken down due to the heat of the tobacco coals*.

The present invention thus overcomes the disadvantages of the prior ait dilution methods and makes possible a cigarette wrapper which allows for the desired degree of smoking satisfaction while providing lower delivery of tars and nicotine to the smoker on a per puff basis as well as on an overall oigarette basis* One embodiment of the present invention, the use of a bubble form of water-soluble material, also provides more efficient ■ ί' dilution and provides visible evidence of the opening of the . t' dilution holes, with the benefit of the full satisfaction from the smoke during the early stages of smoking and the psychological ■i advantages of seeing the dilution holes open during the later stages of smoking.

This invention relates to a cigarette wrapper and method of making the same . More particularly, the invention relates to a oigarette wrapper which is capable of providing undiluted smoke during the early stages of smoking and which provides smoke diluted by air during the later stages of smoking. The invention encompasses cigarette wrapper having Ventilation holes, formed mechanically or otherwise or present in the paper or wrapper due to the inherent porosity of the same, which are covered or filled with a substance which is disintegrated by the action of the ingredients, particularly, the moisture, in the tobacco smoke which results from the burning of the tobaoco in said tobacco product. The ventilation holes in addition to ■', be · in the wrapper of the smoking article or in the walls of a filter associated therewith may be in both the wrapper and filter of a smoking article, the holes being spaced some distance away from the end of the smoking product are closed with a water-soluble material during the initial stages of smoking but are opened during subsequent stages of smoking due to the action of the moisture in the tobacco smoke on the material which initially blocks said holes. A particularly preferred water-soluble material for use in accordance with this invention is polyethylene oici.de , A partlculwrly preferred embodiment of the present invention is the use of a water-soluble material having a cellular or bubble structure. Such materials provide for superior degradation properties when contacted with water and can, if desired be made of substantially the same color as the wrapper in which the holes are located so that the aire virtually unnotice-able before the smoking product is smoked. When the holes are opened by degradation of the film during smoking they assume a darker appearance which is readily noticeable to the smoker* Thus, the smoker can have visible evidenoe of the opening of the dilution holes, with the benefit of the full satisfaction from the smoke during the , early stages of smoking and the psychological advantages of seeing the dilution holes open It is an object of this invention to provide a wrapper for a cigarette which will give substantially undiluted smoke during the early puffs and diluted smoke during the later puffs* It is a further object to provide a cigarette which has a lowered total delivery of smoke components to the smoker. It is a further object to provide a cigarette which the smoker will find to have a reasonable reeistance-to-draw and to give a satisfying smoke. It is a still further object of the present invention to provide a cigarette wrapper which provides visible evidence of the opening of the dilution holes with the benefit of the full satisfaction from the smoke during the early stages of smoking and the psychological advantages of seeing the dilu-tion holes open during the later stages of smoking* · The above and other objects and advantages of the inven- . , ||.. tion will become, apparent from the following description, read in conjunction with the accompanying drawings, in whichi Figure 1 is a perspective view of one embodiment of the present invention, a plain cigarette having openings or vent holes in the wrapper which are covered or filled with a water-soluble cellular plastic film, Figure 2 Is an enlarged fragmentary view of a small area of the covered vent holes in the wrapper of the cigarette in Figure 1.

Figure 3 is a cross-section through one of the covered vent holes in the wrapper of the cigarette shown in Figure 1 and 2, showing the appearance of the ooating before the cigarette is emoked* Figure h is a oross-Bectional view of the same vent holes shown in Figure 3 » after the moisture of the cigarette smoke has ■ ' Γ caused the water-soluble cellular plastic film to break down and the hole to be opened.

Figure 5 is a perspective view of another embodiment of the present invention, a cigarette having openings or vent holes in the filter and in the wrapper, said openings being covered or filled with a water-soluble plastic film.

Referring to Figures 2 and 3 , an enlarged portion of cigarette 1 is shown, as indicated in the drawings, whioh is representative of all openings The objects of the present invention may be realized by providing the paper wrapper or the like of a cigarette or other smoking product with holes of sufficient size to provide significant dilution of the smoke by air, and covering or 'plugging these holes with a film which is susceptible to the action of moisture to such a degree that the moisture-laden smoke from the first portion of the cigarette causes the film gradually to dissolve or disintegrate in such a way that the holes are opened after the first few puffs of the cigarette or the like have been taken* In accordance with this invention, the cigarette delivers undiluted smoke during the initial puff or during the first few puffs, but during the later stages of smoking the cigarette is ventilated, i.e. the smoke is diluted, to any desired degree, as determined by the number and size of the holes, and the nature and thickness of the film covering the holes. The portion of a cigarette rod which should be without such holes will be dependent on the specific rate of action of smoke moisture upon the blocking film and in some instances upon the film thickness. The film and its thickness can be varied to control the proportion of unven-tilated smoke delivered. Preferably this will be the smoke from the first four to six puffs* Th° moisture-susceptible or water-soluble film feay consist of a dextrin, starch, or starch derivative, a natural water-soluble gum, or a water-soluble synthetic polymer which is attacked by high humidity. Natural gums useful as film formers include guar gum, gum arable, tragacanth and pectins. Synthetio resins or polymers useful in the present invention are exemplified by solid polyethylene glyools, polyvinyl alcohols, polyethe-lene oxides, polyacrylic acids and their salts, and polymers of polyvinylpyrrolidone. Various blends of these materials, used in various molecular weights, may also be used* Preferred materials are the water-soluble polyalkylene oxides and polyvinyl alcohols* The polyalkylene oxide may have a molecular weight between about 70,000 and 5,000,000 and greater can be employed in the invention. The preferred molecular weight of the polyethylene oxid is from about .100,000 to about -^00,000.

The polyalkylene oxide film or coating may be prepared using polyethylene oxide or a copolymer of ethylene oxide with less than 50^ by weight of propylene oxide, i.e., oxides containing both -CsiUO- and "C3H O- groups, and may be also mono- or di- esters of such polyalkylene oxides,, for example, the methoxy esters of polyethylene oxides. As used herein, the term ''polyalkylene oxidel! is intended to include all such materials, including the esters, having molecular weight of from about 70,000 to about 5,000,000.

Illustrative of such -materials are polyethylene oxides which have the general formula: wherein x Is an integer having a value of from about 1,600 to about 115,000. Such materials may be prepared, generally, by polymerizin alkaline oxides by conventional methods. For example, ethylene oxide can be reacted in accordance with the following equations to yield the polymer:- • 0 (2) HO-CHa-CHa-OH + (CK CH) HO (~CH2-CH2-0-) , H Particularly- preferred polyalkylene oxides are water- solub solid polyethylene oxide and copolymers containing at least 50 weig percent of ethylene oxide in copolymerized form with up to 50 weigh In a most preferred embodiment of the present invention, polyethylene oxide and/or the above defined copolymers should have reduced viscosity value in the range of from about 1.0 to about 75 or even higher, and most preferably should have a reduced viscosit of from about 2 to about 60. Reduced viscosity is an indirect measurement of the molecular weight of the polymer and it is a val obtained by dividing the specific viscosity by the concentration o the alkylene oxide polymer in the solution, the concentration bein measured in grams of polymer per 100 milliliters of solvent at a given temperature. The specific viscosity is obtained by dividing the difference between the viscosity of the solution and the viscosity of the solvent by the viscosity of the solvent. The reduced viscosities herein referred to are measured at a concentra of 0.2 gram of poly lkylene oxide in 100 milliliters of acetoaitri at 30°C.

Solid alkylene oxide polymers can be prepared by polymerizing an alkylene oxide in the presence of certain metal carbonate catalysts, such as calcium carbonate, barium carbonate, strontium carbonate and the- like. These metal carbonate catalysts can be employed in concentr tions in the range from about 0.J to J parts by weight per 100 parts by weight of alkylene oxide.. The polymeriza ion reaction can be conducted in the liquid phase-.at a ' temperature in the range from about 70 C. to about 150°C. It is " preferred that the metal carbonate catalyst contai not more than one part by weight of non-sorbed water per 100 parts by weight of monomer, and at least 0 .01 part by weight of sorbed water per 100 parts by weight of catalyst. It is also preferred that the - carbonate catalyst be free from ions which reduce their catalytic can be found in the disclosure in United States Patent No. j5, 45 and the disclosure in the United States applications which are referred to therein.

A plasticizer such as glycerol or diethylene glycol may be incorporated in the film former to alter its flexibility; a material not a plasticizer which is hygroscopic, such as calcium chloride, may be incorporated to expedite the action of smoke moisture. In addition, materials which react with water or with smoke constituents may be present in the film or bubble coating to cause its deterioration. For example, citric acid and sodium bicarbonate may be present to react with the smoke constituents to cause a rapid breakdown of the wate -soluble film.

A filler may be added to the film as a source of heterogeneity or of stress concentration to expedite the disin egrating action of moisture. Some fillers useful in this wa include "Alundum", fused alumina, titania, clay, talc, calcium carbonate, silica, aluminum carbide and barium fe rite.

The film-forming solution or dispersion ma be applied by roll- or knife-coating or printing for more viscous compositions, by spray or brush for less viscous compositions. Casting, hot melt coating, and other " rocedures known in the art may be useful in certain instances. Precasting and drying of the film followed application to the perforated paper or other, wrapping web may be' employed .

Other embodiments of this invention are possible. The temporary blocking film may contain an' greeable flavoring agent which is gradually released to the smoke by the action of moisture or particulates. The perforated paper may be treated with a The coated holes may be located in the innerwrap of a filter with the adjacent overtip having open' perforations.

Conversely, the overtip perforations may be coatedjand. those of the innerwrap open. Inherently porous paper may also be employed.

A particular combination which provides outstanding results in accordance' with the present invention, involves the use, in a cigarette of spaced perforations no closer to the smoking end of the cigarette than 20 mm. and havi g a total surface corresponding to from about 0.2 to about 1.5 percent of the total surface area of the cigarette wrap, said perforations being filled with or coated with a film having a thickness of from 3 to 60 micro and preferably 5 t0 15 microns of a polyvinyl alcohol or a polyethylene oxide.

The advantage of employing a film of the type set forth abo over a film or coating which is heat degradable, resides in the mor accurate control, over the opening of the filled perforations or holes and in the fact that holes can be caused to open a much great distance, from the coal in the cigarette, whereby ventilation can be started and maintained at a desired level with greater accuracy and greater variability and whereby lower total particulate matter is produced.

Particularly preferred films or coatings for use in ■ accordance with the present invention are water-soluble cellular materials or bubble coatings.

Moisture-susceptible, i.e. water-soluble, bubble coatings ■ which may be employed in this embodiment include three-dimensional - cellular structures having a multiplicity of microscopic or sub- " microscopic voids distributed throughout their volume beneath the substantially continuous and homogeneous and the film as a whole is opaque because of its heterogeneous physical structure due to such voids 0 When the water -soluble material is contacted with the moisture from tobacco smoke passing past it, it softens and coalesces with attendant collapse of such voids and the opening of the holes filled or covered by such a film or coating.

Under certain circumstances, the coating can be white and can be applied to vent holes in a cigarette whereby the coated hole are virtually invisible. When the cigarette is smoked, the coating is broken down by the moisture in the smoke and the holes open up, turning dark and visible due to the tobacco which is thereby exposed to view.

Such a film may be prepared and applied to the paper base by applying thereto an emulsion of the oil-in-water type, wherein a film-forming plastic is the continuous phase and the dispersed phas i is present in the form of multitudinous droplets,, at least almost all o'f which are of microscopic or submicroscopic dimensions, and by drying the film in such manner that the dispersed phase is evaporated without essential disruption or substantial collapse of the cellular structure of the continuous phase. While the gelation of the plastic film and the' evaporation of the water therefrom may to a certain extent be simultaneous, in general they occur in substantial sequence in that order in that the plastic layer first attains such a degree of semi-solidity as to be effective to drop t dispersed water droplets. The solvent is then evaporated by diffusion through the rigid, or substanti lly rigid, cellular walls of the plastic and is replaced by air forming the voids already referred to. however, and has shown certain advantages.. In this variation, two non-aqueous liquids, less polar than water/ are employed; the two may be miscible, but one is not a solvent for the film-forming resi When the resin is dissolved in the solvent liquid and the second liquid added, a clear solution may result. The dispersed droplets do not appear until the film has been cast and enough of the solven liquid has evaporated to force the separation and coalescence of th non-solvent within the film. The trapped droplets then produce bubbles by the same exchange with air that has been described. The advantage of this system lies in the fact that it does not wet the paper and better control of the application is possible. Bubble coatings may contain pigment but this is usually unnecessary for th purposes of the present invention and would merely obscure the desired change in appearance. The coating may be applied by conventional methods to. the perforated wrapper or mouthpiece materi for example, it may be printed, roll-coated, knife or brush coated, or sprayed. I have found that a form of costing that coats only th perforations is probably most desirable. Coating preferably is' don on the perforated wrapper or the like before the rod is formed, but it could instead take place on the wrapper , tobacco rod or filter ro or the finished cigarette.

The following examples are illustrative: Example 1 A water dispersion was prepared by placing 0 g. of water i a glass blender jar and slowly adding the following ingredients wit agitation at high speed: 3 g. dextrin (canary Ho, ≥6 - Clinton-Corn Processing Co.), 6 g. starch (Mo. C5- 67 - Λ.Ε. Staley Manuf cturing Co.), and g. polyvinyl alcohol ("Elvanol" k6~2 - heterogeneous mixture was heated 15 rai.nutes at l80°F. with stirring to produce a creamy homogeneous mixture. To this were added 9 g. glycerine (Fisher Scientific Co.) and I52 g. water, and the mixture was stirred and heated again in a water bath at l80°F. for 5 minutes. A filler or abrasive, 60 g0 of "Aluridum" fused alumina No.320, - 3 0 mesh (Norton Co.), was stirred into the blend; this additive will settle on standing so that thorough stirring was necessary before application. A very thin coating wa applied to perforated cigarette filter tipping paper by means of a camel's hair brush and the paper was dried in air and then in an oven. The perforated paper had 6 lines of holes running circumferentially, or a total of approximately l80 holes per tip, each about 0.025 sq0 mm. · Cigarettes were assembled as ollows: commercial 20 mm, cellulose acetate tow filters were cut transversely across, 13 mm, from the smoker's end. The tipping paper prepared as described wa used with conventional tipping adhesive o ' the filter exterior to attach the 13 mm. filter portion. t a point 6 mm. back of its original position so that a 6 mm. empty space between filter sec i remained covered only by the new tipping, with the film-covered vent holes located at this space, and to attach the filters to 65 cigarette rods.

These cigarettes were smoked by machine with a modified cigarette holder which permits measurement of air flow through the walls of the filter end of the cigarette, and this by comparison, with the known rate of total flow during puffing will indicate the proportional smoke dilution, usually stated as percent of total flow. The means for determining dilution is a glass sleeve which side arm leading to a flow meter which is open to the air. The. sleeve is covered at each end with thin rubber dam which has a hole through which to slip the cigarette to provide an air-tight fit. The end of the filter tip extending out from this sleeve is placed in the customary mamier in the inlet .side of a Cambridge filter holder with filter., which in turn is connected with a smoking machine. This machine is controlled in a known fashion to draw a 35 cc. puff during two seconds once every minute. The cigarette is lighted during such a puff, and the resistance-to-dra (pressure drop through the cigarette) and air flow during puffing through the filter wrapping is recorded before lighting, during th first (lighting) puff, and during the smoking until an arbitrary butt length of 35 mm, is reached. At that point the cigarette is removed from its holder, puffing is stopped, and the filter and holder are weighed to determine, by comparison with their initial weight, the amount of total particulate matter (TPM) delivered.

In Table I are shown the comparative results from smoking the experimental cigarettes and the same commercial cigarettes without modificat on. Th opening of the holes is demonstrated by the drop in draw resistance as well as by the dilution.

Table 'Ι ?ufff-by-?uff Meas rement of Delayed Dilution' Cig Control Sample 1 RTD* ■ '/■Dilution RTD*- ^Dilution B fore Smoking 4.4 0 3.2 • ■ ■ .' ■ Example 2 Barrier film in aqueous dispersion was prepared as in the preceding example and applied to perforated tipping paper and dried in the manner described. Cellulose acetate filter plugs 20 mm. long prepared from 4 denier/49,000 total denier tow, with innerwrap removed, were attached by means of this tipping paper t 65 mm. tobacco rods from commercial cigarettes „ A cigarette was smoked and changed from 8 percent dilution before smoking to 26 percent after smoking, Example j¾ A non-filter cigarette 85 mm. in length is perforated with a needle with eight holes at about 2 cm. from one end with the result tha . dilution, measured unlit, is approximately 90 . These holes are then painted over a suspension of film-former prepared as in Example 1. The cigarette is exposed to room air for more than 2 hours at 60$ relative humidity. Unlit dilution is measured as zero. The end furthest from the holes is lighted and machine smoking was carried out as before. Dilution increase after the sixth puff to 19 and on the final puff to 4 $.

Example 4 A mixture of 16 g. of polyvinyl alcohol GM-14 (Nippon Gohski, Osaka, Japan) and 400 ml. of water was stirred until all the resin was in solution. Tipping paper having 180 holes totalling Ο.ΟΟ65 sq. in. was coated lightly with this solution an oven-dried The. paper was then used to attach sections of filter tip to a 65 mm. cigarette tobacco rod in the "plug-space-plug" configuration and with the dimensions described in Example 1, The cigarette was smoked and dilution at the beginning and end of Details of dilution holes and tipping paper: Paper 1.8 mils thick (l mil = 0,001 inch) -6 Holes 5 ^ 7 mils or 55 sq, mils each (l sq„ mil = 10 s in 180 holes or total area 65ΟΟ sq. mils.

Total Are Ο.ΟΟ65 sq. in.

Area vs. Dilution for Single Laye of Paper 55 8 550 25 700^. . 40 1500 ~ 60 2100 75 6500 95 Thickness of a representative blocking film, composition of Example 1, is less than that of paper; estimated by microscop O.5O - O.75 mils.

In the. examples which follow, the water-soluble coating material was prepared as follows: One hundred cc. of ethylene dichloride was added to a laboratory blender. The blender was run for a period of two minutes at 1500 revolutions per rainute (rpm). The plastici er, when employed, was added to the ethylene dichloride, while polyethylene oxide was added over a period of one minute and the blender was then run. for an additional five-minute period at i86 rpm. One gram of Varsol No. 5 (a petroleum solvent sold by Ess.o Standard Oil Co. composed principally of paraffins, napthanes avi aromatics) was then added to the mixture in the blender and the blender was run for an additional period of five minutes at i860 rpm. The resulting material was then applied to standard cigarette paper having perforations as indicated in each example application of the liquid solution to. the cigarette paper with a subsequent air drying step resulting in a cellular coating.

The perfora ions in each line as indicated in the examples comprised rectangular punctures of 0.005 to O.OO7 dimensions spaced at intervals of 0,028" in a line such that in the finished cigarette the punctures appeared in a plane paralle to the longitudinal axis of the cigarette „ The spacing of each row of perforations was B lfj> mm. from the center line of the cigarette paper. Distance between lines was 0.22". Cigarette rods bad a 25 mm. section of unperforated paper in the front hal i.e. at the smoking end.

Exam le 5 In this example, 20 grams of a water-soluble polyethylen oxide having a molecular weight, of 300,000 (Polyox WSRN 750) was employed as the polyethylene oxide. The coating material was prepared by the method set forth above. The coating was applied to a cigarette having six lines of perforations consisting of three rows of two lines each. The average thickness of the coating applied to the perforations was nine microns. The cigarette was tested on a standard smoke estin machine (Philip Morris Automatic Smoking Machine of the type sold by Phipps & Bird, Inc.) and was compared with a control cigarette which was exactly the same except that it had no perforations or- coating. The cigarettes were evaluated for total particulate matter on a puff-by-puff basis in accordance with the standard test which is described in Analytical Chemistry, 51, I7O5-I709 (1958), VJartman Cogbill and Harlow. The cigarettes employed had a standard 20 m cellulose acetate filter and a rod of tobacco 65 mm. in length.

Table II Puff Wo. Experimental Cigarette Control Cigarette 1 1.5 mg. 1.5 mg. 2 1.8 1.8 1.9 ■ 2.2 h 2.0 2.5 1.0 2 6 2.1 2.7 7 2.2 2.9 8 2.5 5.1 9 2.5 5.5 Example 6 In this example, 20 grams of a water-soluble polyethylene oxide having a molecular weight of 200,000 (Polyox WSRN- 80) was employed as the polyethylene oxide. The coating material was prepared by the method set forth in Example 5· '^ne coating was applied to a cigarette having nine lines of perforations consisting of three rows of three lines each. The average thickness of the coating applied to the perfor tions was ten microns. The cigarette was tested on a standard smoke testing machine (Philip Morris Automatic Smoking Machine of the type sol by Phipps & Bird, Inc.) and was compared with a control cigarett which was exactly the same except that it had no perforations or coating. The cigarettes were evaluated for total particulate matter on a puff-by-puff basis in accordance with the standard test which is described in Analytical Chemistry, 5,1, I7O5-I7O9 '-(I 8), Wartman, Cogbill and Harlow. The cigarettes employed ha a standard 20 mm. cellulose acetate filter and a rod of tobacco 65 mm* in length. The results obtained are set forth in Table I Table III Experimental Control Puff No. Cigarette Giearette 1 1.5 mg. 1.3 mg. 2 1.5 1.7 3 ' 1.7 1.8 4 1.5 2.0 ' 1.5 2, 6 1.4 2.4 7 1.7 2. 8 1.6 2.8 9 1.8 2.9 2.3 3.3 Example In this example a blend of eight grams- of a water-soluble polyethylene oxide having a molecular weight of 200,000 (Polyox JS W 80) and three grams of a water-soluble polyethylene Gxide (WSK 20) having a molecular weight below 100,000 was employed as the polyethylene oxide. The coating material was prepared by the method set forth in Example 5.

The coating was applied to a cigarette having six lines of perforations consisting of three rows of two lines each. The average thickness of the coating applied to the perforations was. fourteen microns.' The cigarette was tested on a standard smoke testing machine (Philip Morris Automatic Smoking Machine of the typ sold by Phipps & Bird, Inc.), and was compared with a control cigarette which was exactly the same- except that it had no perforations or coating. The cigarettes were evaluated for total particulate matter on a puff-by-puff basis in accordance with the standard test which is described in Analytical Chemistry, 31* 1705- I7O (I 58), Wartman, Cogbill and Harlow. The cigarettes employed had a standard 20 mm. cellulose acetate filter and rod of tobacco 65 mm. in length. The results obtained are set forth in Table IV.

Puff No . Experimental Cigarette Control Cigarette 1 1,5 mg. l.Jl mg. 2 1.7 1.8 3 2.1 2,1 4 .2.2 ' 2.1 2.2 2.5 6 2.1 .5 7 · 2.5 ■ 2.6 8 2.5 2.9 9 2.5 5.3 Example 8 In this example j a blend of ten grams of a water-soluble polyethylene oxide having a molecular weight of 200,000 (Polyox WSRN 80) and two grams of a water-soluble polyethylene oxide (WSR having a molecular weight of four million was employed as the polyethylene oxide. The coating material was prepared by the meth set forth in Example · The .coating was applied to a cigarette having nine lines of perforations consisting of three rows of thre lines each. The average thickness of the coating applied to the i perforations was seven microns. The cigarette was tested on a standard smoke testing machine (Philip Morris Automatic Smoking Machine of the type sold by Phipps & Bird, Inc.), and was compared with a control cigarette which was exactly the same except that it had no perforations or coating. The cigarettes were evaluated for total particulate matter' on a puff-by-puff basis in accordance wit the standard test which is described in Analytical Chemistry, 51* I 0 -I 09 (I958)* War man, Cogbill and Karlow. The cigarettes employed had a standard 20 mm. cellulose acetate filter and a rod tobacco β¾ nim. in length. The results obtained are set forth in Table V.

Table V Puff No. Experinisnta 1 Cigaret1e Control Cigarette 3 2.0 2.1 2.0 2.1 ' 1.9 .2.5' 6 2.1 2.5 7 ■ 2.3 2.6 8 2.5 2.9 9 2.8 3.3 Example In this example, one gram of a plasticizer (Tergitol NP40 sold by Union Carbide Corporation (an alkyl phenyl ether of polyethylene glycol))- was employed in addition to the other ingredients employed in Example 5· Twenty grams of a water-solubl polyethylene oxide having a molecular weight of 200,000 {mm 80) was employed as the polyethylene cxide. The coating material was prepared by the method set forth in Example 5· The coating was applied to a cigarette having six lines of perforations consisting of three rows of two lines each. The average thickness of the coating applied to the perforations was ten microns. The cigarett was tested on a standard smoke testing machine (Philip Morris Automatic Smoking Machine of the type sold by Phipps & Bird , Inc.) and was compared with a control cigarette which was exactly the same except. that it had no perforations or coating. The cigarette were evaluated for total particulate matter, on a puff-by-puff basi in accordance with the standard test which is described in Analytical Chemistry, £1, I7O5-I709 (1958), Wartman, Cogbill and Harlow. The cigarettes employed had a standard 20 mm. cellulose acetate filter and a rod of tobacco 6 mm. in length. In the test cigarettes involved in this example, the perforations v/ere larger than in the preceding example and were rectangular in shape havin the cigarette and 0.014 inch in a direction parallel to the axis' of the cigarette. Λ distance of thirty mm. from the. smoking end. of the cigarette was left without per orations. From this point on toward the smoker's end of the cigarette perforations were present in three rows of two lines each with a distance between the two lines of 0.032 inch and the interval between perforations in the lines was O.JO inch. The results obtained are set forth in Table VI.

Table VI Puff No. Experimental Cigarette Control Cigarette 1 1.5 nig ■ lA mg. 2 1.7 . 1.7 3 1.8 1.8 1.9 1.9 • 1.8 2.3 6 IA 2 A 7 1.6 2.5 8 • 1.7 2.8 9 1.8 3.0 2.0 As mentioned ear-lier in this specificatio , the dimensions and arrangements of the holes or perforations v:ill vary in accordance with the desired results. They may be arranged and. may be of the sizes and shapes shown in the above-mentioned Fig'ge patent or they may have other sizes, shapes and configurations.

A particular combination which provides outstanding ._ results in accordance with the present invention involves the use)' in a cigarette or the like, of spaced perforations no closer- to the smoking end of the cigarette or smoking article than 20 mm. , · said, perforations having a total surface corresponding to from about 0.2 to about 1. $ of the total surface area of the cigarette • wrap_, said perforations being filled with or coated with a film from about 2 to 60 microns and preferably of about 5 to 15 microns of a water-soluble material, most preferably polyethylene oxide.

The advantage of employing a water-soluble film over a film or coating which is not water-soluble } resides in the more accurate control over the openin of the filled perforations or hol and in the fact that the. holes can be caused to open a much greater distance from the coal' in the cigarette whereby ventilation can be started and maintained at a desired level v/ith greater accuracy and greater control.

I have found that the use of a water-soluble bubble coating for closing the perforations or holes provides even greater improvements. Such a water-soluble bubble coating can be caused to open or disintegrate at an even greater distance from the coal than a water-soluble film which is not a bubble coating. Furthermore, t use of a bubble coating'to form the film which seals the holes may be characterized by a white opacity which disappears as the film dissolves or in the moments before when collapse of the bubble structure brings transparency. The smoker can see the vent holes being opened. The bubble structure also results' in a thicker- film from a given weight of material, and this added thickness permits easier control during application. The greater bulk or thickness means that a difference of a fraction of a mil is of less consequence than it would be otherwise. The bubble-co ting technique and the resulting film have been described earlier. The film which results contains many small air bubbles which may occupy much more space, than the solid portion but, in general, the bubbles are not connected. They have roughly the size of the wavelength of visible light and the light-sca tering effect of the bubbles gives eva oration of a liquid which is first dispersed as minute droplets in the continuous phase with which the liquid is .immiscib The continuous phase or binder , which is a solution of the film-former in different liquid, gels after coating is applied, usually due to partial evaporation of the latter liquid. The gel then fixes the liquid-filled bubbles. There is some shrinkage of the structure, during the drying while the liquid is passing out of the bubbles and diffusing to the surroundings and air is replacing it in the bubbles . .

Claims (3)

32164 1. A cigarette wrapper or the like comprising a combustible material having spaced apertures therein, and a film formed from a non-toxic filling material normally closing aald apertures, which filling material comprises an organic water-soluble material selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyethylene glycol and dextrin. 2. The cigarette wrapper of claim 1, wherein said film io a three-dimensional cellular structure, including a multiplicity of discrete microscopic or sub-mioroscoplc enclosed voids beneath the outer surface thereof and distributed throughout the e'olume of the structure. Attorney o^i ^t e applicant .. I

1. Λ cigarette wrapper or the like comprising a combv!Rt:.i.lil o material having spaced apertures therein, and a film formed from a non-toxic filling material normally closing an id apertures ,. which filling material comprises an organic water-soluble material selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyethylene glycol and dextrin.

2. The cigarette wrapper of claim 1, wherein said film is a three-dimensional cellular structure, including a multiplicity of discrete microscopic or sub-microscopic enclosed voids beneath the outer surface thereof and distributed throughout the volume of the structure,

3. The cigarette wrapper of claim 1 wherein said water-soluble filling material is polyvinyl alcohol, t\. The cigarette, wrapper of claim 1 wherein said water-;iolublc filling material is polyethylene oxide.