CytrelÂ® Tobacco SupplementâA New Dimension in Cigarette Design

7 Cytrel® Tobacco Supplement—A New Dimension in Cigarette Design R. W. GODWIN and C. H. KEITH Solvent Spun Rayon, Modified Cellulose Fibers and Derivatives Downloaded from pubs.acs.org by CORNELL UNIV on 06/08/17. For personal use only.

Celanese Fibers Co., Charlotte,N.C.28232

O v e r the p a s t 25 y e a r s t h e r e h a s b e e n a d r a m a t i c d e c r e a s e i n the d e l i v e r y of t a r , nicotine, andother smoke components f r o m cigarettes. This continuing trend has been particularly m a r k e d i n the p a s t f e w y e a r s w i t h the i n t r o d u c t i o n of a l a r g e n u m b e r o f n e w b r a n d s d e l i v e r i n g b e t w e e n 1 a n d 15 m i l l i g r a m s o f tar. T h e s e r e p r e s e n t a l a r g e c h a n g e f r o m t h e 2 5 to 3 0 m i l l i g r a m b r a n d s that w e r e c o m m o n i n the 1940's a n d 5 0 s . T h e tobacco i n d u s t r y h a s b r o u g h t a b o u t t h i s c h a n g e i n r e s p o n s e to c o n s u m e r demand for "lower delivery" cigarettes. n

1 1

!

There a r e a variety of existing techniques which a r e used to d e c r e a s e the s m o k e d e l i v e r y o f c i g a r e t t e s . A m o n g these a r e filtration, porous and/or fast-burning papers, filter ventilation, m o d i f i c a t i o n of the tobacco f i l l e r , a n d changes i n cigarette dimensions. Filtration is most commonly used andgenerally achieves u p to a 5 0 - 6 0 % r e d u c t i o n i n t a r a n d n i c o t i n e d e l i v e r y , b u t i t h a s l i t t l e e f f e c t o n g a s p h a s e c o n s t i t u e n t s {1). Selective filter media s u c h a s c h a r c o a l a r e u s e d i n s o m e b r a n d s to a c h i e v e s i z a b l e r e ductions i n some smoke components, while leaving others relatively unchanged. Porous and/or perforated papers a r e widely used to a c h i e v e 1 0 - 3 0 % r e d u c t i o n s i n b o t h g a s a n d p a r t i c u l a t e p h a s e components. M o r e r e c e n t l y , f i l t e r ventilation b y m e a n s of p e r f o r a t e d t i p p i n g p a p e r s h a s b e e n e m p l o y e d to a c h i e v e a n o t h e r 50 o r m o r e p e r c e n t r e d u c t i o n i n a l l s m o k e c o m p o n e n t s (2). F i n a l l y , changes i n the p a p e r b u r n i n g r a t e , c i g a r e t t e d i m e n s i o n s , a n d the i n c o r p o r a t i o n of expanded tobacco leaf a n d reconstituted tobacco s h e e t h a s b e e n u s e d to c r e a t e f a s t e r b u r n i n g a n d l o w e r p u f f count cigarettes, w h i c h d i r e c t l y translates into l o w e r smoke chemistry.

C y t r e l ® i s a r e g i s t e r e d t r a d e m a r k of the C e l a n e s e C o r p o r a t i o n .

83

84

S O L V E N T SPUN R A Y O N , MODIFIED C E L L U L O S E FIBERS

Solvent Spun Rayon, Modified Cellulose Fibers and Derivatives Downloaded from pubs.acs.org by CORNELL UNIV on 06/08/17. For personal use only.

In g e n e r a l , these techniques a r e u s e d i n c o m b i n a t i o n w i t h e a c h o t h e r to a c h i e v e a l o w e r d e l i v e r y c i g a r e t t e w i t h a d e q u a t e c o n s u m e r a p p e a l . H o w e v e r , e a c h of these e x i s t i n g methods has l i m i t a t i o n s . S o m e w h i c h h a v e b e e n m e n t i o n e d i n c l u d e the a c t i o n of f i l t e r s o n the p a r t i c u l a t e p h a s e of t o b a c c o s m o k e o n l y , a n d the a c r o s s - t h e - b o a r d a c t i o n of v e n t i l a t i o n . B e c a u s e of t h e s e , i t i s d e s i r a b l e to h a v e a d d i t i o n a l t e c h n i q u e s f o r c o n t r o l l i n g t h e d e l i v e r y of v a r i o u s s m o k e c o m p o n e n t s . One s u c h technique, w h i c h has been under development i n o u r l a b o r a t o r i e s f o r a n u m b e r of y e a r s , i s the i n c l u s i o n of t o b a c co s u p p l e m e n t i n a c i g a r e t t e . T h i s m a t e r i a l , w h i c h h a s the t r a d e m a r k e d n a m e C y t r e l , i s a m a n u f a c t u r e d sheet m a t e r i a l of controllable composition w h i c h looks, p r o c e s s e s , and burns like tobacco. It h a s a f u r t h e r d e s i r a b l e p r o p e r t y o f h a v i n g a b l a n d t a s t e u p o n c o m b u s t i o n , so that b l e n d s of C y t r e l w i t h t o b a c c o taste essentially like a m i l d tobacco. I t i s t h e p u r p o s e o f t h i s p a p e r to to d e s c r i b e t h e p h y s i c a l , c h e m i c a l , a n d s o m e o f t h e p e r t i n e n t b i o l o g i c a l p r o p e r t i e s of this m a t e r i a l . T h e effect of C y t r e l i n c l u sion i n tobacco blends is also described. C y t r e l is e s s e n t i a l l y a f i l l e d f i l m m a t e r i a l , f o r m e d by casti n g a n d d r y i n g a s h e e t f r o m a d o u g h - l i k e m i x t u r e of o r g a n i c b i n d e r s a n d a d d i t i v e s w i t h m i n e r a l f i l l e r s (3). A typical compos i t i o n i s g i v e n i n T a b l e I. T h e f i n i s h e d sheet is cut into o n e - i n c h squares w h i c h are subsequently blended with tobacco and m a n u factured into cigarettes by conventional techniques. F o r the p u r p o s e s of t h i s d i s c u s s i o n , c i g a r e t t e s d e s c r i b e d a r e t y p i c a l of the construction commonly utilized in Great Britain. These cigar e t t e s w e r e 7 2 m i l l i m e t e r s l o n g w i t h a c i r c u m f e r e n c e o f 25 m i l l i m e t e r s a n d w e r e e q u i p p e d w i t h a 16 m i l l i m e t e r , d u a l a c e t a t e p a p e r f i l t e r w i t h a t a r r e m o v a l e f f i c i e n c y o f 4 9 % (4). Cigarette w e i g h t s w e r e h e l d c o n s t a n t a t 0 . 98 g r a m , a n d p r e s s u r e d r o p s r a n g e d f r o m 90 m i l l i m e t e r s o f w a t e r a t a n a i r f l o w o f 1 7 . 5 m i l l i l i t e r s p e r s e c o n d f o r t h e a l l - C y t r e l c i g a r e t t e s to 116 m i l l i m e t e r s f o r the a l l - t o b a c c o c i g a r e t t e s . B l e n d e d c i g a r e t t e s c o n t a i n i n g 10, 20, a n d 50% C y t r e l w e r e a l s o p r e p a r e d , a n d puff c o u n t s l i n e a r l y r a n g i n g f r o m 1 0 . 2 to 5 . 8 u n d e r s t a n d a r d s m o k i n g c o n d i t i o n s w e r e o b t a i n e d a s the p e r c e n t a g e of C y t r e l i n c l u s i o n i n c r e a s e d . This c h a n g e i n puff c o u n t o n l y p a r t i a l l y a c c o u n t s f o r the d e c r e a s e s i n deliveries shown later. If i t w e r e t h e o n l y e f f e c t , t h e e x p e c t e d d e l i v e r i e s f r o m a C y t r e l c i g a r e t t e w o u l d be 57% of those of a tobacco cigarette. S i n c e d e l i v e r i e s i n t h e r a n g e o f 0 to 3 8 % a r e f o u n d , i t i s evident that o t h e r f a c t o r s a r e i n v o l v e d . F r o m l o o k i n g at the c o m p o s i t i o n of the m a t e r i a l , i t i s a p p a r e n t that 70% of C y t r e l c o n s i s t s o f i n c o m b u s t i b l e m a t e r i a l , a n d a m a x i m u m o f 30%

7.

GODWIN AND KEITH

T a b l e I:

85

Cytrel Tobacco Supplement

C o m p o s i t i o n of C y t r e l Amount

Material Binder (sodium carboxymethyl Inorganic fillers/combustion Humectant/plasticizer

19% 71%

cellulose)

modifiers

5%

(glycerol)

3% 2%


Colorants F l a v o r additives

can burn during smoking.

T a k i n g 30% of 57% g i v e s

17%,

which

s h o u l d b e the d e l i v e r y of a n y g i v e n c o m p o n e n t i f no c h a n g e i n combustion

occurs.

B e f o r e e x a m i n i n g the r e l a t i v e d e l i v e r i e s of v a r i o u s ponents f r o m C y t r e l and tobacco,

com-

i t i s n e c e s s a r y to r e f e r t o

methods

e m p l o y e d a n d the g e n e r a l p a t t e r n of d e l i v e r i e s .

methods

u t i l i z e d a n d the d e l i v e r i e s of 250

the

The

c o m p o u n d s a n d 75

ele-

ments f r o m these cigarettes have been reported i n a s e r i e s papers by V i c k r o y , Mauldin, f o r s c h u n g (4, j>,

6).

a n d A l l e n i n the B e i t r a g e

Briefly recapitulating,

zur

the v o l a t i l e

collection trap,

graphic techniques

w e r e m e a s u r e d by either gas

or specific tests for individual

(e. g . , h y d r o g e n c y a n i d e , ponents are

components

The semi volatile

of 1 3 0 ° C .

These were analyzed by a

chromatography and mass spectrometry.

densed phase components

(i. e.,

specific techniques.

mass spectography

except for m e r c u r y , spectroscopy.

M

tar

1,

and

a substantial l i n e a r d e c r e a s e i n d e l i v e r y as M

Figure 1

w h i c h i s defined as total p a r t i c u l a t e

c o l l e c t e d o n the f i l t e r p a d m i n u s w a t e r a n d n i c o t i n e . f r o m 15.8

to 3 . 6

milligrams/cigarette.

is a s i m i l a r graph for another important smoke tine i s absent f r o m the C y t r e l f o r m u l a t i o n .

shows matter

It i s

evi-

mixture

Figure 2

component,

I n t h i s c a s e t h e l i n e g o e s to z e r o f o r 1 0 0 % C y t r e l ,

characteristic

mea-

2,

almost

dent that t h e r e i s m o r e t h a n a f o u r f o l d d e c r e a s e i n this of m a t e r i a l s

and

spark

which was

Figures

the a m o u n t o f C y t r e l i n the b l e n d i s i n c r e a s e d . the d e c l i n e i n

con-

collection

chromatographic

3 i l l u s t r a t e the g e n e r a l d e l i v e r y p a t t e r n o b s e r v e d f o r every component,

combina-

The elements were measured by

s u r e d by a t o m i c f l o u r e s c e n c e

tine.

com-

The

those r e m a i n i n g o n the

pad) w e r e m e a s u r e d b y a v a r i e t y of gas source

fiber

chromato-

t h o s e w h i c h c a n b e d i s t i l l e d f r o m the c o l l e c t i o n p a d

at a t e m p e r a t u r e t i o n of gas

nitric oxide).

Tabak-

smoke

c o m p o n e n t s , w h i c h a r e t h o s e w h i c h p a s s t h r o u g h the g l a s s smoke

of

This pattern

of a n u m b e r of n i t r o g e n - c o n t a i n i n g

smoke

t u e n t s b e c a u s e of the r a t h e r l o w n i t r o g e n c o n t e n t of

as

niconico-

is consti-

Cytrel.


S O L V E N T SPUN R A Y O N , MODIFIED

0 100 50 50

Figure 1. Tar delivery

Φ

Figure 2. Nicotine delivery

CELLULOSE

100 % C y t r e l 0 % Tobacco

FIBERS


7.

GODWIN A N D K E I T H


87

F i g u r e 3 shows a s i m i l a r d e l i v e r y p a t t e r n f o r a n i m p o r t a n t gas phase constituent, carbon monoxide. In F i g u r e 4 w e h a v e a n e x a m p l e of o n e of the r a r e i n s t a n c e s where a different pattern is o b s e r v e d . In this case, g l y c e r o l i n c r e a s e s l i n e a r l y a s the a m o u n t of C y t r e l i n the b l e n d i s i n c r e a s e d , g o i n g f r o m z e r o i n t h e u n c a s e d t o b a c c o c i g a r e t t e to 2 . 1 m i l l i g r a m s i n the 100% C y t r e l c i g a r e t t e . In c a s e d cigarettes (such as those u s e d i n the U n i t e d States) w h e r e g l y c e r o l i s c o m m o n l y a d d e d a s a h u m e c t a n t , t h i s c h a n g e i s n o t n e a r l y s o m a r k e d . It i s k n o w n that g l y c e r o l i s d i s t i l l e d i n t o the s m o k e s t r e a m a s a C y t r e l c i g a r e t t e c o m b u s t s , a n d c o m p r i s e s a b o u t 58% of the t a r c o l l e c t e d . O n l y two o t h e r c o m p o u n d s of the 250 e x a m i n e d s h o w a n i n c r e a s e i n d e l i v e r y a s the C y t r e l content i n the b l e n d i s i n c r e a s e d . These a r e : (1) h y d r o g e n s u l f i d e , w h i c h m o d e s t l y i n c r e a s e s f r o m 4 6 to 55 m i c r o g r a m s / c i g a r e t t e , a n d (2) a m m o n i a , w h i c h r e m a i n s c o n s t a n t a t 2 0 - 2 2 m i c r o g r a m s / c i g a r e t t e u p to a 5 0 % b l e n d i n c l u s i o n o f C y t r e l , b u t t h e n i n c r e a s e s to 50 m i c r o g r a m s / c i g a r e t t e f o r a n a l l - C y t r e l cigarette. T h e s e m a t e r i a l s a r e k n o w n to b e d e r i v e d f r o m r e s i d u a l s u l f u r i n the c o l o r a n t u s e d a n d d e c o m p o s i t i o n of a n i t r o g e n e o u s f l a v o r a d d i t i v e , r e s p e c t i v e l y . A m o n g the e l e m e n t s , a l l b u t s o d i u m m a r k e d l y d e c r e a s e a s the C y t r e l c o n t e n t of the b l e n d i s i n c r e a s e d . S o d i u m , w h i c h c a n be d e r i v e d f r o m the s o d i u m c a r b o x y m e t h y l c e l l u l o s e b i n d e r , shows as e r r a t i c i n c r e a s e w i t h i n c r e a s i n g C y t r e l content; but this i s not n e a r l y as m a r k e d as the d e c r e a s e i n p o t a s s i u m , w h i c h i s a m a j o r e l e m e n t i n t o b a c co. A s i n d i c a t e d i n the p r e v i o u s d i s c u s s i o n , a c o m p a r i s o n o f s m o k e c o m p o n e n t d e l i v e r i e s c a n b e s t be done c o n s i d e r i n g the c o m p o s i t i o n s of C y t r e l a n d t o b a c c o . It t h e r e f o r e i s o f i n t e r e s t to e x a m i n e the r e l a t i v e d e l i v e r i e s of a n u m b e r of s m o k e c o m p o n e n t s to s e e i f t h e o v e r a l l c o m b u s t i o n p r o c e s s c a n b e b e t t e r u n d e r s t o o d . F r o m the d i f f e r e n c e s i n p u f f c o u n t s a n d the i n o r g a n i c c o n t e n t of C y t r e l , i t i s e x p e c t e d that the C y t r e l c i g a r e t t e s h o u l d d e l i v e r 17% of the a m o u n t of a n y c o m p o n e n t i n t o b a c c o s m o k e i f a l l o t h e r f a c t o r s w e r e e q u a l . I n T a b l e II the r e l a t i v e d e l i v e r i e s of g a s e s a n d v a p o r p h a s e c o m p o n e n t s a r e l i s t e d a s c a l c u l a t e d f r o m the V i c k r o y d a t a (4). F o r m o s t of t h e s e c o m p o n e n t s , the d e l i v e r i e s a r e n e a r o r b e l o w the e x p e c t e d 17% d e l i v e r y ( w i t h the e x c e p t i o n s p r e viously noted for a m m o n i a and hydrogen sulfide). The l o w levels of a l k a n e s , a l k e n e s , b e n z e n e , and toluene i n C y t r e l s m o k e r e f l e c t the a b s e n c e o f s a t u r a t e d h y d r o c a r b o n s s u c h a s t o b a c c o waxes in Cytrel. T h e r e l a t i v e l y h i g h e r l e v e l s of a l k y n e s , p r i n c i p a l l y a c e t y l e n e , suggest that f r e e r a d i c a l r e a c t i o n s a r e o c c u r r i n g i n the p y r o l y s i s p r o c e s s . The v e r y l o w l e v e l s of a l c o h o l s , f u r a n s ,


88 S O L V E N T SPUN R A Y O N , MODIFIED C E L L U L O S E FIBERS

Figurée. Glycerol delivery

7.

GODWIN A N D KEITH

Table

89


II: R e l a t i v e D e l i v e r i e s o f V a p o r P h a s e Number

Delivery

Delivery

f r o m Tobacco f r o m C y t r e l

of Material

Components

Compounds

(pg/cig)

(ug/cig)

Relat i v e (%)


Hydrocarbons Cj-C^

alkanes

6

2165

312

C i - C

alkenes

10

1106

alkynes

2

48 104

169 18

D

C1-C5

14.4 15.3 37. 5 12. 5 7.4

13

Benzene

1

Toluene

1 2 4

8. 0

7.8

13. 1

W i t h t h i s e x t e n s i v e b a c k g r o u n d of i m p r o v e m e n t s i n the chemic a l and b i o l o g i c a l p r o p e r t i e s of C y t r e l s m o k e , i t i s of i n t e r e s t to e s t i m a t e what C y t r e l i n c l u s i o n c o u l d do f o r e x i s t i n g types of c i g a -


94

SOLVENT SPUN RAYON, MODIFIED CELLULOSE FIBERS

rettes. In this country the most popular brands of cigarettes have a tar delivery of around 17 m i l l i g r a m s , a nicotine delivery of about 1. 2 m i l l i g r a m s , and a carbon monoxide delivery of 15 m i l l i g r a m s per cigarette. Replacing 30% of the tobacco with C y t r e l should reduce these deliveries to 13. 1, 0. 8, and 13 m i l l i grams per cigarette, respectively. Thus, a medium tar brand can be changed to a lower tar brand by inclusion of 30% C y t r e l . S i m i l a r l y , a ventilated low tar brand might have tar, nicotine, and CO deliveries of 8. 0, 0. 6, and 9. 9 m i l l i g r a m s per cigarette. Inclusion of 30% C y t r e l i n the blend could further reduce these to 6 . 5 , 0.4, and 8. 6 m i l l i g r a m s per cigarette, respectively. In conclusion, we have shown that C y t r e l tobacco supplement offers a means to reduce deliveries of virtually a l l smoke c o m ponents of a cigarette. These reductions are for the most part greater than would be expected on the basis of the burning rate of the m a t e r i a l and its composition. The s i m p l e r smoke composition and the reduced deliveries of Cytrel-containing cigarettes a p p e a r to translate into a reduction i n biological response i n animal test systems. Inclusion of C y t r e l i n cigarettes can be readily utilized with other existing techniques to provide lower delivery cigarettes. Abstract C y t r e l i s a tobacco supplement consisting of m i n e r a l components, combustion modifiers, and organoleptic-active materials bound together by a film-forming cellulose ether. C y t r e l i s being used i n several brands of cigarettes on the European market at a 20-25% level blended with tobacco. The amount of "tar" c o n t r i buted to the "mainstream" smoke by C y t r e l i s one-fourth to one-seventh of that from tobacco. There are s i m i l a r reductions for other non-nitrogeneous smoke constituents relative to tobacco. Neither C y t r e l nor C y t r e l smoke contains nicotine, and the number and amount of nitrogen-containing compounds i n C y t r e l smoke are d r a s t i c a l l y reduced. S i m i l a r l y , the amount and complexity of the combustion products i n C y t r e l "sidestream" smoke are significantly reduced. It has been shown that the delivery of smoke components from blends of C y t r e l and tobacco is reduced in direct proportion to the level of C y t r e l i n the blend with tobacco. This relationship has been demonstrated for virtually all the components of smoke studied to date. C y t r e l can be readily blended with tobacco i n conventional cigarette making equipment. F u r t h e r , Cytrel/tobacco blend technology is fully compatible with other means currently being used to modify cigarette smoke, such as various cigarette filters and high porosity cigarette papers.


7.

GODWIN AND KEITH


95

L i t e r a t u r e Cited 1. Keith, C. Η., P r o c . 3rd W o r l d Conf. Smoking and Health, DHEW Publication No. (NIH) 76-1221 (1976), 1, 49. 2. Norman, V., B e i t r . z. Tabakforsch. (1974), 7, 282. 3. Miano, R. R., and K e i t h , C. H., U . S. Patent 3, 931, 824 (1976). 4. V i c k r o y , D. G., B e i t r . z. Tabakforsch. (1976), 8, 415. 5. Mauldin, R. Κ., B e i t r . z. Tabakforsch. (1976), 8, 422. 6. A l l e n , R. Ε., and V i c k r o y , D. G., B e i t r . z. Tabakforsch. (1976), 8, 430. 7. Buch, S. et a l , Inveresk Research International Report 307, Project 403318 (1975). 8. Bernfeld, P., and Homburger, F., B i o - R e s e a r c h Consul tants, Inc. Report, P r o j e c t C-211 (1975). 9. Black, A . et al, Inveresk R e s e a r c h International Report 408, P r o j e c t 403365 (1975). 10. G o r i , G. Β., "Towards L e s s Hazardous Cigarettes, Report No. 2, The Second Set of Experimental Cigarettes, " Nation al Cancer Institute, Smoking and Health P r o g r a m , Washing ton, D . C . (1976).

CytrelÂ® Tobacco SupplementâA New Dimension in Cigarette Design

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