DE1209474B - Cigarette filters - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Int. Cl .:

A24b

GERMAN

PATENT OFFICE

EDITORIAL

German class: 79 c-2

Number: 1209 474

File number: L 44642IV a / 79 c

Filing date: April 16, 1963

Opened on: January 20, 1966

It is known to use a fiber-like filter in cigarette filters Basic substance, which can also contain a plasticizer, also incorporate substances that Due to their selective effect, extract particularly undesirable substances from the smoke. So one has z. B. the filters added water-soluble polyethylene oxides in powder form, especially the tarry Withhold parts of the smoke. As much restraint as possible is desirable of these substances may be from a health point of view. are this specific effect Limits are set, since the cigarette smoke would otherwise have too great a loss of smell and taste substances learns, so that many smokers reject such "health cigarettes". Also educate the water-soluble polyethylene oxides with the water vapor contained in the smoke and with the Filters invading saliva slimy deposits that can lead to complete clogging of the filter.

There was therefore a need for impregnation substances which are free from the above disadvantages and yet have a specific effect with regard to particularly harmful smoke components.

It is well known that these harmful substances include phenols and phenolic compounds often in vapor form in the smoke and therefore through normal filters without special impregnation not be held back.

It has now been found that impregnation of the cigarette filters with certain polymeric compounds, which is a complex compound with phenol and phenolic substances in tobacco smoke form, offers special advantages. The filters impregnated in this way adsorb phenol and phenolic compounds selectively from the tobacco smoke and, if appropriately prepared, do not keep any too high amounts of tar substances.

The compounds according to the invention as impregnation of cigarette filters from a with The basic substance provided with plasticizers belong to two groups. The first group are the polymers of N-vinyl-5-methyl-2-oxazolidinone with the following structural formula:

CH ₂ = CH

/ Nn

O = C

CH ₂

CH ₃

Cigarette filters

Applicant:

P. Lorillard Company, New York, N.Y.

(V. St. A.)

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse and
Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Bad luck man,
Patent Attorneys, Munich 9, Schweigerstr. 2

Named as inventor:

Alexander W. Spears,

William E. Routh,

Chase W. Lassiter,

Jimmy H. Bell, Greensboro, N. C. (V. St. A.)

Claimed priority:

V. St. ν. America April 16, 1962

(188 281),

of March 19, 1963 (266 212)

and the copolymers of this compound, which in addition to at least 25 percent by weight of N-vinyl-5-methyI-2-oxazolidinone contain another vinyl monomer.

The second group consists of certain water-insoluble polyglycables, corresponding to one of the general ones Formulas:

HXOH
R (X0H) "
R - N ₀ (XOH) ₂₆
HO

i Il

R-N-C- XOH

and

O H

HO

where R is the remainder of a saturated hydrocarbon

so substance with 2 to 6 carbon atoms and X is a polymer chain of the formula - (OR% -, in which R ' is an alkylene radical with 2 to 6 carbon atoms,

509 779/131

and α is 1, 2 or 3 and b is 1 or 2; According to the invention, these polyglycols contain 10 to 37%, preferably 16 to 37%, of ether oxygen, which is understood to mean the —O— group, which is inserted between the successive alkylene groups in the X chain.

It is known that certain polyethers of structural formula (1), i. H. Polyalkylene oxides or polyglycols, Soluble in water, such as, among others, the polyethylene oxides and their copolymers with moderate Amounts of higher alkylene oxides. They are therefore not suitable as an impregnation, while z. B. the polymers, in which the alkylene group contains 3 or more carbon atoms, insoluble in water and are suitable for the filter impregnation according to the invention.

The molecular weight of the complex-forming compound present as impregnation, by which the indices y and ζ in the polyglycol compounds are determined, can be quite different. When selecting substances with a suitable molecular weight, the crucial point is that the vapor pressure of the complex-forming compound must be so low that it remains in the filter and is not volatilized while smoking the cigarette. The vapor pressure must be at most 40 mm Hg at 25 ^° C., the preferred vapor pressure being at most 1 mm Hg / 25 ^° C.

Another limitation on the molecular weight of the polymeric compound is that the compound must be soluble in the plasticizer with which the filter thread substance is provided.

If polyglycols of the formula (1) to (4) are used, the molecular weight can be over a considerable Range can vary up to more than a few thousand. Are diisocyanates according to the When using formula (5), the polymer should preferably not have more than one or two urethane linkages exhibit. Is the urethane linking group in proportion to the number of existing ones If ether bonds are too strong, the polymer becomes insoluble in the plasticizer substances.

Among the compounds listed above, those of the formula R (XOH) _{0 are} preferred in which a has the value 2 or 3, in particular the glycerol derivatives of propylene oxide, for example compounds of the formula C3H5 - (XOH) ₃ , in which X is ( OC ₃ He) ₂ stands.

Compounds of groups (3) to (5) are preferred over compounds of group (1).

Compounds of groups (2) to (5) are known per se by reaction of a lower Alkyl mono-, di- or tri-alcohol, a lower alkylamine or diamine or one lower alkyl isocyanate or diisocyanate with a lower alkylene oxide or glycol. Valuable compounds can also be made different by the reaction of alkylene groups Chain length containing alkylene oxides or glycols with alcohols, amines or isocyanates with Alkyl groups of different chain lengths are produced.

Various typical polyglycols are listed in Table I below, this listing is just incomplete.

Table I.

Formulas of polymers
Condensation products Ange
approached
Mole
weight Monomer units Available at Trade name Commercial directory of
Manufacturer
(Manufacturer's Trade
Bulletin) C ₃ H ₅ KOC ₃ H ₆ ) ^ - OH] ₃ 3,000 Glycerin
Propylene oxide union
Carbides
Chemicals
Co. Niax LG 56 “Union Carbide
Chemical Co.
Technical Bulletin
Niax Polyethers «
(1961) C ₃ H ₅ KOC ₃ H ₆ ) ^ OH] ₃ 1000 Glycerin
Propylene oxide the same Niax
LG 168 the same C ₆ HnKOC ₃ H ₈ M) H] ₃ 5,000 Hexane triol
Propylene oxide the same Niax
LH T-34 the same C ₆ Hu (OCeHe) ^ OH 4100 Trimethanol
propane
Propylene oxide Wyandotte
Chemicals
Corp. Pluracol
4040 “Wyandotte Chemi
cals Technical Bull
tin Pluracol TP
Triols «(1958) [HO (C ₂ H ₄ OVC ₃ H ₆ O) Z] ₄ N ₂ C ₂ H ₄
x = y 2,500
3,000 Ethylenediamine
Propylene oxide
Ethylene oxide the same Tetronic
740 “Wyandotte Chemi
cals Technical Bull
tin Tetronic Series "
(April 29, 1957) HO (C ₃ H ₆ O) ^ C ₃ H ₆ OH 2,000 Propylene glycol
Propylene oxide union
Carbides
Chemicals
Co. Niax PPG
2025 “Union Carbide
Chemicals Co.
Technical Bulletin
Niax Polyethers «
(1961)

continuation

Ange Monomer units Available at Trade name Commercial directory of Formulas of polymers
Condensation products approached
Mole
weight N vinyl Dow Devlex 130 Manufacturer
(Manufacturer's Trade
Bulletin) (CH ₂ CH) .. 150,000 5-methyl- Chemical “Dow Chemical 2-oxazolidinone Corporation Corporation Tech nical bulletin / \ Devlex 130 " O = C CH ₂ (August 1960) i
CH ₃

According to the invention, an ordinary cigarette filter made from a fiber substance with the impregnated complex-forming compounds. Cellulose, regenerated cellulose, cellulose acetate or other cellulosic fibers are the most economical and commercially available in this context preferred substances. Such fibers are usually in the form of a rope or a tow manufactured and the tow according to the state of the art to a compact plug for the Preservation of a filter with a greater number of tortuous passages for the retention of the solid and liquid substance particles that may be present in tobacco smoke, processed.

It is known that during the manufacture of such cigarette filters the tow can be powdery Substances such as water-soluble polyethylene oxide are added. In general, these do Additives an increased surface area for the separation of condensed tars and other similar substances. The polyethylene oxide added in this way gives the filter a higher surface area and does the same especially for holding condensed Tars from tobacco smoke suitable, creating a filter with increased effectiveness for the Separation of tars is formed. If a strong effectiveness for tar separation of is considered desirable by some, the separation of large amounts of tar tends to be but to undesirably flatten the taste of tobacco smoke.

According to the invention, the complex-forming compounds are used in one for the fiber base used plasticizer and then dissolved the fiber base in the way with them impregnated that the plasticizer solution containing the complexing agent on the thread tow to act is brought. According to a working method known in the art, the tow then processed into a compact filter plug. In this context, a Sufficient amount of the plasticizer complexing solution on the tow to act come so that a filter with a content of 0.01 to 25% of the complexing agent based on the amount by weight the fiber substance is obtained. In this context, the optimal range lies between 0.3 and 2 percent by weight of the amount of fiber substance.

When a cellulosic fiber substance is used, many known plasticizers can be used. These include glycerol esters of lower fatty acids such as glycerol triacetate. Esters of citric acid with lower alkyl alcohols and lower fatty acids like Triethyl citrate, acetyl triethyl citrate and esters of phthalic acid with lower alkyl alcohols.

A preferred plasticizer is glycerol triacetate. The plasticizer can be in an amount up to present at 20 percent by weight in the finished filter.

2s The filters produced according to the invention have a number of advantages. It was found that the complex-forming Substances have the property of a selective adsorption capacity for phenol and phenolic Possess compounds from tobacco smoke. Typical compounds exhibiting this property are the polyalkylene oxides as well as the condensation products of alkylene oxides with Alcohols or amines, as they have been described above. It is believed that in the case of the occurrence of polyglycols in the complex formation reaction of the ether oxygen Has the function of a Lewis base and that in a corresponding manner the percentage of ether oxygen represents a measure of the number of binding sites per molecule. In the case of the oxazolidinone polymers it is assumed that phenol and phenolic compounds are bound in a complex via a charge exchange.

A significant advantage is the ease with which cigarette filters can be manufactured a content of selective adsorbents. In the manufacture of cigarette filters must continue another point of view must be taken into account.

As already said above, it is known to filter powdered polyethylene oxides for tobacco smoke filters Add to improve their effectiveness for the filtration of tar.

This improvement in the filter efficiency only comes about by the fact that a closer packing together and a higher internal surface area in the filter plug for formation arrives, which, however, also involves applying a stronger pull.

do If desired, such filters can be packed more loosely be, whereby a filter with a more comfortable tensile stress is formed which, however, no longer shows any improvement in terms of its overall filter effectiveness. the Manufacture of cigarette filters according to this procedure also makes additional undesirable Processing stages required. When manufacturing cigarette filters, the installation of additional

Fabrics in the thread tow, however, are preferable in such a way that further work steps are not necessary required are.

This is achieved through the use of the substances according to the invention, in addition to their complex-forming ability with phenol and phenolic substances the distinguishing feature their solubility in the plasticizers used for the production of the fiber base. A solution of one or more complexing agents in a plasticizer can thus be prepared which is absorbed by the fibers after being added to the tow. The Fadenwerg will then processed in a known manner into filter plugs, which have approximately the same tensile stress have without this additional process steps during the manufacture of the filter are needed.

As a result, such filters have approximately the same overall filter efficiency, i.e. that is, they are capable of to separate the same amounts of tar and in addition to this in a selective manner phenol and capture phenolic compounds from tobacco smoke.

Another advantage is achieved through the use of the compounds according to the invention. Besides their solubility in the common ones used in connection with cellulose fibers The compounds according to the invention are not water-soluble in plasticizers. This is true in In contrast to the above-mentioned polyethylene oxides, which are water-soluble. According to her Uses in the manufacture of cigarette filters are the same of potential wetting exposed by saliva. If water-soluble substances are used in such a filter, then the water-soluble resin is converted into a rubbery mass, which is obviously undesirable is. In contrast, the fiction are subject to

20th

2S

30 of water-insoluble substances are not of such unpleasant phenomenon.

The cigarette filters according to the invention are discussed in more detail by the following examples. To the A typical cellulose acetate filter is shown in Example 1 for comparison. Corresponding Example 1 and the subsequent explanations were used for the preparation of the Filter base used filter tow made of cellulose acetate with a solution of glycerol triacetate and impregnated with a solution of each of the various complexing agents in varying amounts.

The cigarettes made with it were smoked in a special device and the Products passing through the filter were collected and analyzed, each experiment being carried out four times became.

The terms »filter effectiveness« and used in the following tables and examples "Phenol filter effectiveness" refers to the percentage of substance particles or of Phenol and phenolic compounds that are separated from tobacco smoke.

example 1

A solution of a complexing polymer and a suitable one was applied to the filter threads Brought plasticizer to act. Each of the various complexing substances was with glycerol triacetate in a weight ratio of 1: 3 to 1:15 parts of the complexing compound to 1 part of the plasticizer mixed and added to the cellulose acetate fibers. The fibers so treated were on processed into filter plugs in the usual way. A filter was used for comparison made of glycerol triacetate without the addition of a complexing substance. The results are shown in Table II below.

Table II
Filters with a content of complexing compounds mixed with glycerol triacetate as a plasticizer

Complexing
link * Weight
ratio of
complex-forming
connection to
Plasticizers 7th
7th
7th
15th
3
7th
: 15
7th
7th ** weight
percent of
Fiber substance
lot denier
the
Threads total
denier length
mm tow
train Total filter
effectiveness
% Phenol filter
effectiveness
% no 6th
6th
6th
6th
6th
5
5
5
5
5 3.2
3.2
3.2
3.2
3.2
3.2
2
3.2
3.2
3.2 55,000
55,000
55,000
55,000
55,000
55,000
42,000
55,000
55,000
55,000 17th
17th
17th
17th
17th
17th
20th
17th
17th
17th 0.48
0.46
0.44
0.46
0.42
0.39
0.36
0.48
0.46
0.45 47.0
45
49
47.5
49
47
61
48
48
47 71.5
84
87
88
91
89.5
94
86
88
86 Niax PPG 2025 ..
NiaxLHT-34 ...
NiaxLG-168 ....
NiaxLG-168 ....
NiaxLG-168 ....
NiaxLG-168 ....
Niax LG-56
Tetronic 704
Pluracol 4040 1
1
1
1
1
1
1
1
1

* See Table I for the composition of these compounds. ** 6% plasticizer present in the fiber substance.

Example 2

A solution of vinyl acetate in ethanol and glycerol triacetate in a mutual weight ratio of 1: 2: 7, in which the monomer units in approximately the same molar amount, was at a concentration of 6 percent by weight mixed with the fibers of cellulose acetate. The filter threads used had one Denier of 3.2. Filter plugs were made from the threads. The filter plugs possessed a total denier of 55,000, a length of 17 mm and a tensile strength of 0.49. the Overall filter efficiency was 49% and the phenol filter efficiency 85.5%.

The copolymer used in this example is commercially available and is available from the »Dow Chemical Company "under the trade name" Devi ex A 515 "and in" Dow Chemical Corporation Bulletin, Devlex A 515 ”dated August 1960.

The values listed in Examples 1 and 2 were all within a few weeks of the Prepare the samples received. In normal practice, the length of time between manufacture may be and consumption is about 2 months. As a result, it is appropriate to persistence to determine this filter with regard to its aging over a period of 2 months.

Example 3

Filter cigarettes with a filter made of cellulose acetate and glycerol triacetate according to the specified Table I and filter cigarettes with the same filter, but with an additional content on »Niax LG 168« were kept for a period of 2 months and then examined for their phenol filter effectiveness. In terms of its nature, the »Niax LG 168« had one Content of an antioxidant in the form of butylated hydroxytoluene in an amount of 250 parts 1 million added by the manufacturer to increase the durability of the joint. The cigarettes made in this way were divided into two groups, one of which was immediate smoked and the other was only smoked after a storage period of 2 months. the The results obtained here are summarized in Table III.

10

Table III Durability of Cigarette Filters

sample Phenol filter
effectiveness
% change
within
2 months Cellulose acetate and
Glycerol triacetate ....
Niax LG 168 and GIy-
⁰ cerin triacetate (1:15)
Niax LG 168 and Gly
cerium triacetate (1: 7) ..
Niax LG 168 and GIy-
¹⁵ cerium triacetate (1: 3) .. 67
76
89
88 -4.5
-15
0
0

The various filters mentioned in the above examples are for illustrative purposes only has been described and do not imply any limitation on the subject matter of the invention also refers to equivalent and correspondingly varied implementation methods.

The substances according to the invention for filters of filter cigarettes and filter cigars, insofar as these are not used for Delivery to areas outside the scope of the Food Act are intended for the time being on the basis of the "Ordinance on Tobacco and Tobacco Products (Tobacco Ordinance)" of December 19, 1959 (Federal Law Gazette Part I, No. 52 of December 22, 1959,

P. 730), especially Appendix 1, item 5, not permitted.

Claims (3)

Patent claims: 1. Cigarette filters made from a fibrous base substance with a plasticizer, marked with g e by impregnation with either a) a polymer of N-vinyl-5-methyl-2-oxazolidinone or a copolymer which, in addition to at least 25 percent by weight of this compound, contains another vinyl contains monomer,
or b) a polyglycol. that's one of the formulas 45 R (XOH) « - (XOH) ₂₆ (D RN ₆ - 0
Il (2) H (3) R-N-C-XOH or HO —X-O- OHH O ■ C - N - R - N - C - X- corresponds to where R is the residue of a saturated hydrocarbon having 2 to 6 carbon atoms. X is a polymer chain of the formula - (OR ') z-, in which R' is an alkylene radical having 2 to 6 carbon atoms, a = 1, 2 or 3, b = 1 or 2 and that is 10 to 37, preferably 16 to 37 percent by weight Contains ether oxygen, wherein the impregnation agent has a vapor pressure of at most 40 mm, preferably at most 1 mm Hg at 25 ° C and is insoluble in water, but is soluble in the plasticizer present.
2. Cigarette filter according to claim 1, characterized in that the impregnating _{agent is a polyglycol of the formula CaH s} (XOH) 3, where X is a polymer chain of the formula - (OC3H ₆ ) _Z - in which the number ζ of the chain links is chosen is that the polyglycol at 25 ⁰ C has a vapor pressure of at most 40 mm, preferably at most 1 mm Hg, contains 16 to 37 percent by weight of ether oxygen and is insoluble in water, but is soluble in the plasticizer present. 3. cigarette filter according to claim 1 or 2, characterized by a content of 0.01 to 25, preferably 0.2 to 3%, based on the weight of the fiber, of impregnating agent.