Patent Publication Number: US-5253660-A

Title: Reduced sidestream smoke smoking article wrappers, methods of making such wrappers and smoking articles made from such wrappers

Description:
SUMMARY OF THE INVENTION 
     This invention relates to smoking articles, such as cigarettes, cigars and the like, and the wrapper for the tobacco column thereof, that provide acceptable burn rates, produce light-colored, well-formed ash which clings tightly without premature flaking, have significantly reduced sidestream smoke generation compared to conventional cigarettes and deliver both mainstream and sidestream smoke with acceptable taste and aroma. These desirable properties are achieved when certain defined levels of ULTRACARB (a mineral additive and a paper filler consisting of two homogeneously intermixed minerals, viz huntite and hydromagnesite). 
     The ULTRACARB may be used as the only filler, or in combination with calcium carbonate co-filler, in combination with magnesium hydroxide and calcium carbonate co-fillers, or in combination with magnesium hydroxide, calcium carbonate and carbon co-fillers, to produce a base cigarette paper or cigar wrapper. The paper may be subjected to treatment with burning chemicals, such as alkali metal salts of carboxylic acids. ULTRACARB wrappers can be employed as a normal cigarette paper or as an inner liner. Organic or inorganic acid treatment of such papers can be utilized to improve the subjective taste properties of the resulting cigarettes. Such papers can also be used in combination with filter dilution and perforation of the base paper to optimize taste and mainstream smoke yields. 
     BACKGROUND OF THE INVENTION 
     The reduced sidestream smoke cigarette paper patents which describe magnesium oxide/magnesium hydroxide as paper fillers, and which define burning chemical types and levels, are U.S. Pat. Nos. 4,231,377; 4,450,847; 4,881,557; and 4,915,118. These patents claim alkali metal acetates, citrates, nitrates, carbonates ad tartrates as burning chemical types at levels in the sheet ranging from 0.5% to 8.0%. 
     Other patents which relate to reduced sidestream smoke cigarette papers are U.S. Pat. Nos. 4,461,311 and 4,805,644. These patents disclose sodium and potassium salts of succinic, carbonic, formic, acetic, propionic, malic, lactic, glycolic, citric, tartaric, fumaric, oxalic, malonic, nitric, and phosphoric acids at levels in the sheet up to 25% weight. U.S. Pat. No. 4,805,644, dealing with reduced sidestream smoke cigarette paper, discloses that various paper fillers with superficial surface areas of at least 20M 2  /g result in a wrapper that provides reduced sidestream smoke when incorporated in paper at 5% to 50% by weight. 
     U.S. Pat. No. 3,744,496 discloses a carbon-filled paper wrapper for cigarettes and/or cigars, preferable used as an inner liner with regular cigarette paper or cigar wrapper as an outer wrap. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It has been experimentally determined that cigarette paper with ULTRACARB as a filler in the furnish of the paper, by itself, or in combination with a calcium carbonate co-filler, or in combination with calcium carbonate and magnesium hydroxide co-fillers, or in combination with calcium carbonate, magnesium hydroxide and activated carbon co-fillers, provides an enhancement in sidestream smoke reduction compared to that of a conventional calcium carbonate-filled cigarette paper while maintaining acceptable ash quality, static burn rate, mainstream and sidestream taste and aroma. The truly novel feature of this invention is the reduced sidestream smoke obtained with this unique filler. ULTRACARB is a novel mineral based on a unique deposit of two homogeneously intermixed minerals, viz huntite Mg 3  Ca(CO 3 ) 4  and hydromagnesite Mg 4  (CO 3 ) 3  (OH) 2 .3H 2  O. On exposure to heat, the minerals in ULTRACARB decompose presumably as follows: 
     
         Mg.sub.3 Ca(CO.sub.3).sub.4 3 MgO+CaO+4CO.sub.2 
    
     
         Mg.sub.4 (CO.sub.3).sub.3 (OH).sub.2.3H.sub.2 O 4MgO+3CO.sub.2 +4H.sub.2 O 
    
     These reactions are strongly endothermic with a heat change ΔH=1000 J/g and generate non-combustible, non-toxic, non-corrosive gases. ULTRACARB mineral filler is marketed in the U.S. by Anzon Incorporated, 2545 Aramingo Avenue, Philadelphia, Pa. 19125, and is supplied worldwide by Microfine Minerals Limited, Raynesway, Derby, Great Britain. 
     
         ______________________________________                                    
PARAMETERS OF THE INVENTION                                               
                % of the Basis Weight of Paper                            
______________________________________                                    
Basis Weight of Paper:                                                    
                20 to 100 g/M.sup.2 (preferred 35 to                      
                65 g/M.sub.2)                                             
ULTRACARB Content:                                                        
                5% to 50% (preferred 10% to 35%)                          
Calcium Carbonate Content:                                                
                0% to 40% (preferred 10% to 30%)                          
Activated Carbon Content:                                                 
                0% to 25% (preferred 0% to 15%)                           
Magnesium Hydroxide                                                       
                0% to 25% (preferred 5% to 15%)                           
Content:                                                                  
Acid Addition:  0% to 10% (preferred 0% to 3%)                            
Porosity Base Sheet:                                                      
                3 to 50 (cm/min) CORESTA                                  
                preferred 5 to 15 (cm/min)                                
                CORESTA                                                   
ULTRACARB Types Untreated and surface modified                            
                (stearate, olefinic treated),                             
                ULTRACARB U5, ULTRACARB                                   
                C5, ULTRACARB C5-25                                       
                ULTRACARB P5-20 and L5                                    
Burning Chemical:                                                         
                Alkali metal salts of carboxylic                          
                acids selected from a group consist-                      
                ing of citric, malic, lactic, glycolic,                   
                tartaric, fumaric, maleic, malonic,                       
                glutaric, adipic, acetic and succinic,                    
                in combination with or without                            
                sucrose and organic carboxylic                            
                acids named above.                                        
Burning Chemical Addition                                                 
                0.5% to 6%                                                
Rate:                                                                     
Smoking Articles:                                                         
                Cigarettes, Cigars, and the like                          
______________________________________                                    
TYPICAL PROPERTIES OF ULTRACARB                                           
TYPES U5, L5, C5, C5-25 AND P5-20                                         
______________________________________                                    
U5                                                                        
Typical Chemical                                                          
Analysis:                                                                 
Magnesium      as MgO          38%                                        
Calcium        as CaO          8%                                         
Silicon        as SiO.sub.2    0.3%                                       
Aluminum       as Al.sub.2 O.sub.3                                        
                               0.06%                                      
Potassium      as K.sub.2 O    0.01%                                      
Iron           as Fe.sub.2 O.sub.3                                        
                               0.02%                                      
Sulphur        as SO.sub.3     0.02%                                      
Titanium       as TiO.sub.2    0.02%                                      
Loss on Ignition                                                          
               (44% CO.sub.2 + 9% H.sub.2 O)                              
                               53%                                        
Acid insoluble matter          0.2%                                       
Water soluble salts            0.1%                                       
Typical Physical                                                          
Properties:                                                               
Specific Gravity               2.5                                        
Oil Absorption g/100 g         40                                         
Refractive index                                                          
               mean            1.56                                       
Specific Surface area                                                     
               m.sup.2 /g      15                                         
(nitrogen absorption)                                                     
Mean spherical diameter                                                   
               Micron          0.16                                       
(nitrogen absorption)                                                     
Color: Tristimulus Values                                                 
               X               95                                         
(MgO = 100)    Y               95                                         
               Z               94                                         
Bulk Density - loose                                                      
               Kg/liter        0.23                                       
pH             (10% aqueous    9                                          
               suspension)                                                
Particle shape                 platey                                     
Typical Particle Size                                                     
Distribution                                                              
Percentage finer as                                                       
                10 micron      99.9                                       
measured by Micromeritics                                                 
                 5 micron      95                                         
&#34;Sedigraph&#34;      2 micron      80                                         
                 1 micron      70                                         
               0.5 micron      65                                         
               0.2 micron      55                                         
L5                                                                        
Typical Chemical                                                          
Analysis                                                                  
Magnesium      as MgO          38%                                        
Calcium        as CaO          8                                          
Silicon        as SiO.sub.2    0.3%                                       
Aluminum       as Al.sub.2 O.sub.3                                        
                               0.06%                                      
Potassium      as K.sub.2 O    0.01%                                      
Iron           as Fe.sub.2 O.sub.3                                        
                               0.02%                                      
Sulphur        as SO.sub.3     0.02%                                      
Titanium       as TiO.sub.2    0.02%                                      
Loss on ignition                                                          
               (44% CO + 9% H.sub.2 O)                                    
                               53                                         
Acid insoluble matter          0.2%                                       
Water soluble salts            0.1%                                       
Typical Physical                                                          
Properties                                                                
Specific Gravity               2.5                                        
Oil Absorption g/100 g         40                                         
Refractive Index                                                          
               mean            1.56                                       
Specific Surface Area                                                     
               m.sup.2 /g      15                                         
(nitrogen absorption)                                                     
Mean Spherical Diameter                                                   
               Micron          0.16                                       
(nitrogen absorption)                                                     
Color: Tristimulus Values                                                 
               X               95                                         
               Y               95                                         
               Z               94                                         
Bulk Density - loose                                                      
               kg/liter        0.23                                       
pH             (10% aqueous    9                                          
               suspension)                                                
Particle shape                 platey                                     
Thermogravimetric                                                         
Analysis                                                                  
                               Cumulative                                 
Approx. Decomposition                                                     
               Weight          Weight                                     
Temperature (degree C.)                                                   
               Loss %          Loss %                                     
100 (moisture) 0.5             0.5                                        
300            5.5             6                                          
400            14              20                                         
500            11              31                                         
600            16              47                                         
700            6               53                                         
Thermal decomposition onset temperature 230° C.                    
P5                                                                        
ULTRACARB P5 is a carboxylate-coated, partially hydrated                  
magnesium calcium carbonate.                                              
Technical data for the uncoated product ULTRACARB U5 also                 
applies for the surface-treated P5 version. The only significant          
differences are lower oil absorption (30 g oil per 100 g), slightly       
higher loss on ignition and a slightly lower pH.                          
ULTRACARB P5 offers the same benefits over the standard, un-              
coated U5 grade that are offered by the stearate-coated C5 range.         
ULTRACARB P5 is preferred over C5 grades where higher                     
loading levels are desired.                                               
The standard product, having a 2% surface coating is                      
ULTRACARB P5-20. Coating levels can be varied, e.g.,                      
ULTRACARB P5-10 has a 1.0% coating.                                       
C5                                                                        
ULTRACARB C5 is a stearate-coated, hydrated magnesium                     
calcium carbonate.                                                        
Technical data for the uncoated product ULTRACARB U5 also                 
applies for the surface-treated C5 version. The only significant          
differences are lower oil absorption (30 g oil per 100 g), slightly       
higher loss on ignition and a slightly lower pH.                          
The standard product having a 1% stearate coating is                      
ULTRACARB C5-10. Stearate coating levels can be varied, as                
desired; e.g., ULTRACARB C5-25 has a 2.5% coating.                        
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                                           TABLE 1                                 
__________________________________________________________________________
        Basis                                       Static                
Cigarette                                                                 
        Weight                                                            
            CaCO.sub.3                                                    
                Mg(OH).sub.2                                              
                     ULTRACARB                                            
                             Carbon                                       
                                  Porosity          Burn                  
                                                          SSDR.sup.1      
Paper   (g/M.sup.2)                                                       
            (%).sup.3                                                     
                (%).sup.2                                                 
                     (%)     (%)  Coresta                                 
                                       Fillers      (mg/min)              
                                                          (mg/min)        
__________________________________________________________________________
Control -                                                                 
        22.5                                                              
            30.0                                                          
                0.0  0.0     0.0  25.0 CaCO.sub.3   56.7  2.13            
Ecusta                                                                    
12556                                                                     
Heavyweight +                                                             
        45.0                                                              
            20.0                                                          
                0.0  0.0     0.0  9.0  CaCO.sub.3   50.7  1.46            
1% Citrate                                                                
RSS.sup.3                                                                 
        45.0                                                              
            15.0                                                          
                0.0  25.0    0.0  6.0  ULTRACARB U5 51.6  0.95            
                                       CaCO.sub.3                         
RSS.sup.3                                                                 
        45.0                                                              
            15.0                                                          
                0.0  25.0    0.0  6.0  ULTRACARB C5-10,                   
                                                    49.5  0.90            
                                       CaCO.sub.3                         
RSS.sup.3                                                                 
        45.0                                                              
            15.0                                                          
                10.0 15.0    0.0  7.0  ULTRACARB U5 51.3  0.85            
                                       CaCO.sub.3, Mg(OH).sub.2           
RSS.sup.2                                                                 
        45.0                                                              
            10.0                                                          
                10.0 20.0    0.0  6.0  ULTRACARB U5 49.7  0.87            
                                       Mg(OH).sub.2, CaCO.sub.3           
RSS.sup.2                                                                 
        45.0                                                              
            5.0 10.0 25.0    0.0  6.0  ULTRACARB U5 45.9  0.84            
                                       CaCO.sub.3, Mg(OH).sub.2           
RSS.sup.2                                                                 
        45.0                                                              
            0.0 10.0 30.0    0.0  7.0  ULTRACARB U5 47.6  0.98            
                                       Mg(OH).sub.2                       
RSS.sup.2                                                                 
        45.0                                                              
            0.0 0.0  40.0    0.0  6.0  ULTRACARB U5 52.3  0.99            
RSS.sup.2                                                                 
        45.0                                                              
            0.0 10.0 30.0    0.0  6.0  ULTRACARB U5 35.2  0.63            
                                       Mg(OH).sub.2                       
RSS.sup.2                                                                 
        45.0                                                              
            0.0 0.0  40.0    0.0  7.0  ULTRACARB U5 49.5  0.93            
RSS.sup.4                                                                 
        45.0                                                              
            15.0                                                          
                25.0 0.0     0.0  10.0 Mg(OH).sub.2, CaCO.sub.3           
                                                    75.3  0.93            
RSS.sup.4                                                                 
        45.0                                                              
            25.0                                                          
                15.0 0.0     0.0  10.0 Mg(OH).sub.2, CaCO.sub.3           
                                                    74.9  1.09            
RSS.sup.3                                                                 
        45.0                                                              
            20.0                                                          
                10.0 0.0     10.0 5.0  Mg(OH).sub.2, Carbon               
                                                    49.5  0.77            
                                       CaCO.sub.3                         
RSS.sup.3                                                                 
        45.0                                                              
            5.0 10.0 15.0    10.0 4.0  Mg(OH).sub.2, ULTRACARB            
                                                    44.9  0.65            
                                       U5, CaCO.sub.3 carbon              
RSS.sup.3                                                                 
        45.0                                                              
            0.0 10.0 20.0    10.0 4.0  Mg(OH).sub.2, ULTRACARB            
                                                    44.3  0.65            
                                       U5, carbon                         
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 .sup.1 SSDR = Sidestream Delivery Rate (mg/min)                          
 .sup.2 Burning Chemical Content  8% potassium citrate                    
 .sup.3 Burning Chemical Content  6.5% potassium + 3% citric acid + 6%    
 sucrose                                                                  
 .sup.4 Burning Chemical Content  4.8% potassium acetate                  
 COMMENTS ON TABLE 1                                                      
 It can be concluded from Table 1 that ULTRACARB fillers are effective in 
 significantly reducing the sidestream smoke delivery rate either as a    
 paper filler by itself, in combination with calcium carbonate and        
 magnesium hydroxide cofillers, or in combination with calcium carbonate, 
 magnesium hydroxide and carbon cofillers. Burn rate control depends upon 
 burning chemical type and level, sheet porosity, filler type and level an
 sheet density.                                                           
 
    
     
                       TABLE 2                                                     
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Ash Properties                                                            
Test Cigarettes - Commercial &#34;LIGHTS 100&#39;s&#34; with standard                 
paper removed and replaced with the experimental reduced                  
sidestream smoke cigarette paper.                                         
Cigarette Paper                                                           
             Static Ash   Puffed Ash                                      
______________________________________                                    
Control.sup.1                                                             
             Tight shrinkage                                              
                          Tight shrinkage                                 
             Light Grey   Light Grey                                      
             No flake fall off                                            
                          No flake fall off                               
             Solid sheath Small adhering flakes                           
45 g/M.sup.2.spsp.2                                                       
             Tight shrinkage                                              
                          Tight shrinkage                                 
ULTRACARB - 40%                                                           
             Light Grey   Light Grey                                      
             Few loose flakes                                             
                          No flake fall off                               
             Small flakes Small flakes                                    
45 g/M.sup.2.spsp.3                                                       
             Tight shrinkage                                              
                          Tight shrinkage                                 
ULTRACARB - 25%                                                           
             Light Grey   Light Grey                                      
Calcium Carbonate -                                                       
             No flake fall off                                            
                          No flake fall off                               
15%          Solid sheath Solid sheath                                    
______________________________________                                    
 .sup.1 Ecusta 12556 cigarette paper: 30% calcium carbonate; 25 CORESTA   
 porosity; 25 g/m.sup.2 ; 0.55 citrate burning chemicals.                 
 .sup.2 40% ULTRACARB U5 filler: 6 CORESTA porosity; 45 g/M.sup.2 ; 6.5%  
 potassium citrate + 3% citric acid + 6% sucrose burning chemical.        
 .sup.3 25% ULTRACARB U5 filler: 15% calcium carbonate filler; 6 CORESTA  
 porosity; 45 g/M.sup.2 ; 8% potassium citrate burning chemical.          
 Comments on Table 2                                                      
 The data in Table 2 indicate that both ULTRACARB by itself and the       
 ULTRACARB/calcium carbonate combination result in ash properties very    
 similar to that obtained with regular cigarette paper (control).         
 
    
     
                       TABLE 3                                                     
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Particle Size and Surface Area Characteristics of                         
ULTRACARB Filler                                                          
                              Particle                                    
                                      Specific.sup.(2)                    
                              Size.sup.(1)                                
                                      Surface                             
                  Chemical    Sedigraph                                   
                                      Area                                
Filler   Vendor   Composition (μm) (M.sup.2 /g)                        
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ULTRA-   Anzon    Huntite     0.16    15                                  
CARB U5           Hydromagnesite                                          
ULTRA-   Anzon    Huntite     0.16    15                                  
CARB C5           Hydromagnesite                                          
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 .sup.(1) Particle Size measured by Micromeritics Sedigraph instrument.   
 .sup.(2) Surface Area measured by B.E.T. Nitrogen Adsorption method.     
 Comments on Table 3                                                      
 It should be noted that specific surface area for ULTRACARB is only 15   
 M.sup.2 /g which is less than the minimum 20 M.sup.2 /g filler surface   
 area claimed by Hampl, et al, (U.S. Pat. No. 4,805,644), as being require
 for effective sidestream smoke reduction. The outstanding sidestream smok
 reduction demonstrated by cigarettes wrapped in papers containing        
 ULTRACARB fillers contradicts the Hampl, et al, claim that sidestream    
 smoke reduction increases with increasing filler surface area.