Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D1/00—Cigars; Cigarettes
  • A24D1/02—Cigars; Cigarettes with special covers

Definitions

• This invention concerns smoking articles such as cigarettes which use a wrapper normally comprising fibres of organic origin mixed with inorganic fillers and sometimes containing amounts of soluble chemical additives, binding agents and processing aids.
• a conventional wrapper In the case of a cigarette a conventional wrapper would be predominantly comprised of wood and/or textile fibres mixed with inorganic filler such as calcium carbonate. These materials may be subject to a refining process and mixed in various proportions such that the wrapper properties can be widely varied to confer on the cigarette different characteristics such as smoulder rates, air permeability, ash quality, appearance and taste.
• Cigarette paper technology has been developed sufficiently to establish relationships between paper parameters such as filler/fibre ratios and properties such as inherent permeability and opacity. These relationships are well known, as indeed are many of the relationships between paper properties and the performance of cigarettes constructed with these papers.
• cigarette papers constructed in the conventional way are not homogeneous mixtures of fillers and fibre throughout their cross section.
• the distribution of the filler tends to change from one side to the other due to the nature of the wet draining process and filtration effect of the fibre.
• conventional papers have normally a degree of asymmetrical fibre/filler mix which has a moderate but important effect on their performance especially in relation to ash formation.
• US Patent 3395714 describes the use of two thin sheets to form a composite wrapper wherein the outer sheet is a conventional cigarette paper and the inner sheet in contact with the tobacco is a heat insulating plastic film with a melting point below 440°C.
• the specification also proposes manufacturing as two sheets or as a composite with two sheets glued together or by depositing the plastic film as a solution upon the sheet of cigarette paper.
• This patent proposes benefits for these systems which benefits include: changes in the low temperature distillation zone affecting smoke taste, reduced tobacco consumption between puffs and reduced emission of sidestream smoke.
• US Patent 3633589 proposes a composite wrapper composed of two thin sheets both consisting of vegetable fibre stock so as to provide the benefits claimed for US 3395714 without the disadvantages of plastic films.
• US 3633589 provides no teaching as to the method by which the two thin sheets are linked but indicates that the composite wrapper is constructed but of independently manufactured papers described as conventional cigarette paper outer sheet and a calendered inner sheet which is practically impervious to air.
• the present invention seeks to utilise the advantages of a multiple layer sheet whilst at the same time overcoming the practical difficulties of using double or multi sheet wrappers.
• it is desired to have the benefit of combining the properties of different paper wrappers without the manufacturing difficulties associated with either laminating sheets in an off-line process or attempting to manufacture cigarettes with two paper wrappers run simultaneously on the cigarette making machine.
• it is desired to avoid the disadvantages of laminating adhesives.
• a wrapper for smoking articles which wrapper comprises a single paper sheet which is formed from two or more discrete webs, which webs are combined while at least one of the webs is still in its wet stage of formation prior to drying.
• the webs are formed from different stock. (Stock being the ingredients of the headbox or reservoir).
• said two or more webs are combined when all of the webs are in the wet stage of formation prior to drying.
• the wrapper is of low air permeability and preferably said permeability is 10 Coresta or less.
• two partially formed webs are combined and one web is a substantially unfilled web having a low basis weight. Conveniently said weight is 20 gm ⁇ 2 or less and said one web prevents or substantially reduces staining or said one web contains activated carbon.
• the other web is a filled web conferring a conventional appearance on the wrapper, for example the opacity of the wrapper is 60% or more. It may be that the filler of said other web comprises predetermined amounts of calcium carbonate (up to 50% by weight) or the filler of said other web comprises predetermined amounts of selected fillers, e.g. Mg(OH)2, Al203, Li0H and high surface area CaCO3.
• the total basis weight of the wrapper is less than 50 gm ⁇ 2 but in other arrangements the total basis weight of the wrapper is less than 35 gm ⁇ 2.
• one or more of the webs may contain a burn retardant such as ammonium phosphate or a burn enhancer such as a soluble salt of a group I or group II metal, maybe up to 10% by weight.
• a burn retardant such as ammonium phosphate or a burn enhancer such as a soluble salt of a group I or group II metal
• a smoking article comprising a rod of smoking material and a wrapper having any of the above features.
• duplex as used in this specification is intended to cover sheets which comprise two or more webs wherein at least one web is in the partially formed wet stage prior to drying when the two or more webs are combined or superposed.
• the adhesion between the two layers is achieved by the fibre bonding inherent in the papermaking process.
• this method of formation introduces an interaction between the two or more layers, which interaction can have a surprising effect on the air permeability of the final duplex sheet.
• the component webs may be formed from different stocks arising from separate headboxes or reservoirs on a multi-wire machine, or at least one web may be produced off-line and re-introduced as a finished sheet to the wet stage of a second paper making machine. In either method of manufacture the objective is to use the fibre structure to provide an integral sheet formed of two or more layers which is capable of being used as a wrapper for smoking articles.
• duplex papers are also asymmetric in that the proportion of fibre to filler may vary from one side of the sheet to the other, it is possible with duplex papers to provide a radical change and alteration in properties from one side to the other rather than the gradual change of properties associated with single wire sheets of conventional form.
• duplex papers it is possible using duplex papers to provide a paper sheet having differing characteristics on one side of the paper from those on the other.
• Table 1 shows air permeability data obtained with the Gurley system for duplex papers and the component parts.
• the component parts i.e. inner and top layers or webs, were acquired at the paper making machine by sampling from each web without the two becoming joined together. The sample was then finish treated as a normal sheet.
• the Gurley system of air permeability measurement is suitable for assessment of cigarette papers which have low permeabilities relative to usual commercial standards.
• the method involves measurement of the time taken to displace a fixed volume of air through a defined area of paper under the constant load of a weighted falling piston.
• the apparatus is sold commercially by W & L E Gurley, Fulton Street, Troy, New York 12181. The test is set out in ISO 3687-1976. In the table, adjacent columns do not correspond.
• Table 1 Air Permeability Data Sample No Duplex Top Layer Inner Layer Double Wrap 3 30 000 11 4.5 13 23 375 10 5 14 10 6 17 11 10 8 9 6 760 000 65 670 5500 725075 57 550 6950 64 830 4950 52 3140 68 42
• Table 2 provides data on tensile strength, basis weight and opacity of duplex papers and its component parts. Opacity being measured on a standard EEL machine (according to BS 4432), on which standard cigarette papers have opacities of 60% or more.
• the duplex sheet has been formed from two stocks, one of which provides the characteristics of highly impermeable paper and the other of which provides some of the characteristics of conventional cigarette paper, particularly in relation to appearance.
• One particular embodiment of the present invention provides a duplex paper for use in the manufacture of cigarettes, which paper has been formed from two or more stocks one of which has a composition that provides the characteristics of a highly impermeable paper and the other of which is stock suited to the manufacture of chalk filled cigarette papers.
• wrappers of smoking articles having unusual non-homogeneous cross-­sectional characteristics there are many uses for wrappers of smoking articles having unusual non-homogeneous cross-­sectional characteristics, but one of particular interest is for use with the product of our co-pending British application No 8901579.6 of 25 January 1989, which forms the basis for European application No 90300750.8.
• a paper can be made which will readily self-­extinguish the cigarette but such papers are normally of the Papirossi type having a high fibre density and low opacity characteristic of impermeable paper sheets.
• the highly impermeable, low opacity paper could be overwrapped with conventional cigarette paper.
• the disadvantage of this proposal is that the overwrapping must be done on the cigarette making machine or the two wraps must be laminated thus suffering from the disadvantages outlined above.
• Double wrapping has been employed commercially in the U.S.A. by Philip Morris on the Virginia Superslims brand, but in this construction it results in a total paper basis weight of 70 gm ⁇ 2 compared to conventional papers at about 25 gm ⁇ 2.
• the two components of the double wrap must be exceptionally low basis weight and may be low in strength which would therefore be difficult and in some cases impossible to make or use commercially as a single sheet.
• the problem can be solved by forming a duplex paper in which a stock for highly impermeable low opacity paper is used to produce a partially formed web which is combined with a partially formed web made from stock of a more conventional cigarette paper, the two partially formed webs being combined before drying to form a duplex sheet having differing characteristics from one side of the sheet to the other.
• the conventional appearance can be placed on the outside of the cigarette with a lower opacity reverse side against the tobacco, thus providing the characteristics required for the product without detracting from the appearance, and without staining etc.
• duplex cigarette paper with a weight of 32 gm ⁇ 2; this being comprised of a dense low permeability, low opacity layer of 15 gm ⁇ 2 and a higher permeability, higher opacity chalk-filled layer.
• Table 3 Conventional cigarette paper making methods will not produce a paper with the same properties as this duplex sheet. Further reductions in basis weight are feasible with this system whilst still maintaining acceptable appearance, strength etc.
• Table 4 shows thickness data for a range of duplex formulations.
• Table 4 Thickness Data for Duplex Paper and Component Parts (micrometres) Sample No Duplex Top Inner 1 49 38 22 3 57 49 25 8 65 46 34
• the paper characteristics may be designed to modify taste, burn rate, sidestream smoke delivery, ignition proclivity or even to achieve changes in appearance.
• the construction can provide opportunities to include paper additives or fillers with beneficial effect such as improvements to the ideas contained in the patent literature.
• the outer surface may include a disproportionately high level of calcium carbonate of normal or enhanced specific surface area such as is suggested in GB Patent 2191930A while the inner surface provides control of air permeability, strength and staining, and where this construction has as its objective reductions in sidestream smoke.
• wrapper modifications have been suggested in the literature to improve taste and reduce smoke deliveries as for example in US 4225636 and US 4505282 where a carbon inner liner is proposed.
• a similar objective could be achieved with a duplex wrapper where the external surface provides conventional appearance and the internal surface contains a suitable proportion of activated carbon.
• the resulting wrapper might even be designed to provide a suitable combustion source to meet the requirements of one of the embodiments described in co-pending UK patent application No 8901579.6.
• the system might also be designed with a low absorbing inner surface as a solution to yellow spotting during storage of cigarettes without a need for double wraps which has been proposed by at least one commercial paper manufacturer.
• a duplex wrapper for cigars may also be devised as a means of replacing the binder and overwrap currently used in the manufacture of the majority of cigars.
• the advantage of a duplex construction is to provide scope in the formulation of the two surfaces not achievable with conventional paper made wrappers in order to enable the desired appearance, burning properties and taste to be achieved.
• duplex papers discussed in this specification are formed from stocks which are made up in accordance with recognised paper making techniques and which can contain, either separately or as chosen mixtures, textile fibres (such as flax or hemp), hard wood fibres, soft wood fibres and other fibres (such as esparto).
• duplex paper used predominantly with examples quoted in co-pending application No 8901579.6 had the following specification: Table 5 Duplex Paper Specification used for Co-pending Application 8901579.6 Basis Weight, gm ⁇ 2 Fibre Type Duplex 37 40% Pine 20% Birch Top 25 40% Eucalyptus Inner 12 70% Pine 30% Birch Calcium Carbonate, % (Top Layer) 22 Air permeability, Gurley(s) 385000 Sample Code 0589987
• Cigarettes were made with expanded tobacco blend to a density of 143 Kgm ⁇ 3 and incorporating the fuel element described in the co-pending application. These were compared in smoking test with commercial cigarettes to establish mainstream and sidestream total particulate matter (TPM) deliveries. The results in Table 6 were obtained.
• Ash characteristics were improved compared with ordinary low air permeability papers and further improvements were observed with the use of ash conditioning additives, for example potassium citrate applied at levels up to 7% of paper weight.
• Coresta permeability is a standard measure used in the tobacco industry for cigarette paper air permeability.
• the apparatus involves a sample clamp which exposes a 2 cm2 sample to a constant pressure of 1 kilo Pascal and provides a means of measuring the flow rate through the sample. Results are quoted in units of ml/min/cm2/K Pa.
• Cigarette samples were made for mainstream and sidestream smoking tests to a specification which is consistent with some UK low tar commercial cigarettes, i.e. 59mm tobacco rod, 25 mm filter, 24.9 mm circumference, 210 kg m ⁇ 3 oven dry tobacco density, and 45% tip ventilation.
• duplex paper samples were selected on the basis of previous test data and were treated with a solution of potassium citrate to achieve the levels shown in Table 9 below. Treatment was carried out by surface contact between the top side of the duplex paper and the liquid reservoir, followed by subsequent drying and rewinding. The process could be replicated through the usual on-line cigarette paper machine soluble additive application facilities such as a size press, and other soluble additives selected from the range of cigarette paper additives known in the prior art would be suitable.
• the cigarette dimensions were typical of UK commercial brands but tobacco density was reduced to 110 kg m ⁇ 3 using cut tobacco expanded by at least 75% of its bulk volume using a commercially available tobacco expansion process.
• the precise level of expansion or mixture of expanded and non-expanded tobacco is a matter for determination in order to achieve an acceptable balance of cigarette draw resistance, tobacco rod firmness and combustion rate.
• the cigarette construction was as follows: 59 mm tobacco rod, 25 mm filter, 24.8 mm circumference, 110 kg m ⁇ 3 oven dry density, 50% tip ventilation, and 100% of highly expanded cut tobacco blend.

Landscapes

• Paper (AREA)
• Cigarettes, Filters, And Manufacturing Of Filters (AREA)
• Manufacture Of Tobacco Products (AREA)
• Grain Derivatives (AREA)
• Cereal-Derived Products (AREA)
• Nitrogen Condensed Heterocyclic Rings (AREA)
• Container Filling Or Packaging Operations (AREA)
• Supplying Of Containers To The Packaging Station (AREA)
• Investigating Or Analysing Biological Materials (AREA)
• Meat, Egg Or Seafood Products (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=10657465

Family Applications (1)

Country Status (16)

Cited By (13)

Families Citing this family (2)

Citations (6)

• 1989
  • 1989-05-26 GB GB898912238A patent/GB8912238D0/en active Pending
• 1990
  • 1990-05-01 IE IE901591A patent/IE901591L/xx unknown
  • 1990-05-08 CA CA002016251A patent/CA2016251A1/en not_active Abandoned
  • 1990-05-23 AT AT90305610T patent/ATE121908T1/de not_active IP Right Cessation
  • 1990-05-23 ES ES90305610T patent/ES2071766T3/es not_active Expired - Lifetime
  • 1990-05-23 DE DE69019073T patent/DE69019073T2/de not_active Revoked
  • 1990-05-23 DD DD90340950A patent/DD295973A5/de not_active IP Right Cessation
  • 1990-05-23 DK DK90305610.9T patent/DK0407022T3/da active
  • 1990-05-23 JP JP2131452A patent/JPH0365172A/ja active Pending
  • 1990-05-23 EP EP90305610A patent/EP0407022B1/de not_active Revoked
  • 1990-05-24 PT PT94143A patent/PT94143A/pt not_active Application Discontinuation
  • 1990-05-24 PL PL28532690A patent/PL285326A1/xx unknown
  • 1990-05-25 HU HU903202A patent/HUT55617A/hu unknown
  • 1990-05-25 FI FI902638A patent/FI902638A0/fi not_active Application Discontinuation
  • 1990-05-25 NO NO90902325A patent/NO902325L/no unknown
  • 1990-05-28 BR BR909002503A patent/BR9002503A/pt unknown

Patent Citations (6)

Also Published As

Similar Documents

Legal Events