NO841332L - TOBACCO FILTER - Google Patents

Description

The present invention relates to a tobacco filter which has a high rate of removal of harmful and dangerous substances contained in tobacco smoke.

As a material in tobacco filters, various types have been proposed so far such as cellulose acetate, paper, rayon, polypropylene, etc., some of these materials have already been used in practice, but they are not necessarily the satisfactory materials for tobacco filters in terms of the removal effect of harmful or dangerous substances, especially carcinogenic substances contained in tobacco smoke.

Various proposals have been made for the removal of harmful substances in tobacco smoke, such as the addition of a hemin compound containing trivalent iron to the filter material (published Japanese patent application 39767/1982), the addition of L-ascorbic acid stearate (published Japanese patent application 49700/1973), the addition of cyclodextrin ( published Japanese patent application 125100//1975), etc.

As a result of studies carried out on a filter which to a significant extent removes harmful and dangerous substances, especially the supposed carcinogens contained in tobacco smoke, it has now been discovered that the desired effect can be achieved by having a phthalocyanine compound present in the filter material.

The present invention therefore relates to a tobacco filter which is characterized in that a phthalocyanine compound, or a phthalocyanine compound with a strong water-absorbing material, is present in the tobacco filter material.

In order, according to the present invention, to have the phthalocyanine compound present in the filter material, there are different methods available, such as adding the phthalocyanine compound per se to the filter material, adhering the phthalocyanine compound to the filter material, chemically binding to the filter material and introducing a substance consisting of another material to which the phthalocyanine compound is adhered, or combined, in the filter material.

In the present invention, "phthalocyanine", which constitutes the phthalocyanine compound, may be such phthalocyanines as non-metallic and those containing copper, nickel, cobalt, aluminum, iron, etc.

The phthalocyanine compound in the present invention is well known within the dyestuff and pigment industry, and in the present invention it is advantageous to use phthalocyanine compounds such as phthalocyanine pigments, phthalocyanine direct dyes, phthalogen dyes, sleep dyes, kype dyes, reactive dyes, etc.

Dyes other reactive dyes and pigments are suitable for addition or made adherent (dyeing) to the material, while reactive dyes are suitable for chemical bonding to the base material.

In the present invention, the filter material can be any known product such as cellulose acetate, cotton, paper, rayon, polypropylene and water or other materials such as protein, polyamide, polyvinyl alcohol and modified products thereof, silicon dioxide gel and polystyrene. These materials can be used in the form of fibres, powders, balls, solutions etc.

In particular, material suitable for binding reactive dyes can be organic or inorganic substances having hydroxy, amino, mercapto or carboxylamide groups, e.g. polysaccharides, e.g. cellulose, starch, "cepharose", etc., proteins, e.g. wool, silk, etc., polyamides e.g. nylon, polyacrylamide, etc., polyvinyl alcohol or modified products thereof, silicon dioxide gel, etc. The phthalocyanine compound is suitably added or made adherent or chemically bonded to these materials by means of the known methods.

In the present invention, it is advantageous to mix a strong water-absorbing material in the form of fiber or powder with the filter material during its manufacture. Such a water-absorbing material is used to keep the moisture in the filter during smoking. It can be used in a fairly large amount, but to maintain the fiber strength, the amount is preferably no more than 10% by weight of the filter.

Strongly water-absorbing polymers such as e.g. can be graft copolymers of starch/sodium acrylate, copolymer salts of isobutylene/maleic anhydride, copolymer salts of styrene/maleic anhydride, cross-linked sodium polyacrylate, graft copolymers of polyvinyl alcohol/acrylate, saponified copolymers of vinyl ester/ethylenically unsaturated carboxylic acid or derivatives thereof, etc. High molecular weight electrolytes containing carboxylate salt are particularly polymers that have a high water absorbing capacity and still have excellent strength even after absorbing water. They are preferred materials for the present purpose. An example is "Sumikagel F-33" or cross-linked sodium polyacrylate.

In the present invention, a material which is generally known within filter technology, such as activated carbon, can alternatively be used at the same time.

The filter according to the present invention effectively removes by absorption harmful or dangerous substances that are present in tobacco smoke, e.g. harmful aromatic compounds and heterocyclic compounds, especially those compounds having two, especially more than two, aromatic rings, such as benzopyrene, preferably in the presence of moisture, although the absence of moisture is not an exclusive condition.

In the present invention, tobacco filters can usually be present in a cigarette holder or pipe but, depending on the type of materials used, it can be placed at one end of the cigarette.

Phthalocyanine used in the present invention, e.g. copper phthalocyanine, can be illustrated as a compound of the following formula, hereinafter designated "CuPc":

Phthalocyanine compounds used in the present invention are described in the literature as pigments or dyes, e.g. on pages 316-1109 of the new edition of "Dyestuff Guidebook" published by The Synthetic Organic Chemistry Association, Maruzen Co., Ltd., published July 20, 1970, or "The Color Index". The following compounds can be given as specific examples: A . Dyes;

CI. Direct Blue 86 (Direct Dye)

CI. Kype blue 29 (kypef argestof f )

("Nihonthrene Brilliant Blue 4G" paste)

B. Pigments:

CI. Pigment blue 15

CuPc (alpha type)

CuPc (beta type)

CI. Pigment blue 16

Pc (non-metallic phthalocyanine)

CI. Pigment blue 17

CI. Pigment green 7 CI. Pigment green 36 C. Reactive dyes; CI. Reactive Blue 7 CI. Reactive blue 15

(1<<>JUm<<>3, 3<<>Jl+m+n<<>4, 1<<>n<<>2, 1<<>£<<>3)

CI. Reactive sheet 21

(1<<>n<<>3, 1<<>m<<>2, 2<<>m+n<<>4)

CI. Reactive blue 7 5

("Cibacron Pront Turquoise G"; a reactive dye).

CI. Reactive blue 116

("Levafix Turquoise Blue E-BA"; a reactive dye)

CI. Reactive blue 118

("Sumifix Turquoise Blue GS"; a reactive dye)

CI. Reactive blue 148

("Sumifix Turquoise Blue BF"; a reactive dye)

CI. Reactive blue 105

("Levafix Turquois Blue P-BRA"; a reactive dye)

CI. Reactive blue 18

("Cibacron Turqoise Blue TG-E"; a reactive dye)

CI. Reactive blue 41

("Cibacron Turquoise Blue 2G-E"; a reactive dye)

CI. Reactive blue 71

("Procion Turquoise Blue H-A"; a reactive dye)

CI. Reactive blue 25

("Procion Brilliant Blue H-5G"; a reactive dye).

CI. Reactive blue 80

("Levafix Turquoise Blue E-4G"; a reactive dye)

CI. Reactive blue 3

("Procion Brilliant Blue H-7G"; a reactive dye)

CI. Reactive blue 72

("Cibacron Turquoise Blue GR-D"; a reactive dye)

These dyes can be added, adhered or bound to the substrate using known methods. E.g. a reactive dye can be bound to a cellulose substrate in an aqueous medium in the presence of an alkaline agent.

When a pigment sold on the market is used as the phthalocyanine compound, such a product usually contains various impurities that have arisen by contamination during the manufacture of the products, or they have been given a surface treatment suitable for their applications. It is therefore desirable to extract or wash the products with a solvent before use. When a filter material is colored with the dyes, it is desirable to separate the colored element with an aqueous medium so that the dye is not easily released when the element is used for the purpose of the invention.

The thus obtained phthalocyanine compound can be placed in filter material, preferably in a moist atmosphere, although a dry atmosphere is not excluded.

The following examples illustrate embodiments of the present invention.

Reference ( 1)

In 600 ml of water placed in a 1 liter container, 30 g of pure cotton was added. The mixture was slowly stirred and heated to 30°C. Then 2 g of "Sumifix Turquoise Blue G" (a reactive dye, color index (C.I.), reactive blue 21) and 30 g of anhydrous sodium sulfate were added. The mixture was stirred for 20 minutes. Then 12 g of sodium carbonate were added. After stirring for 15 minutes at 30°C, the temperature of the mixture was raised to 70°C within 20 minutes. The reaction was allowed to proceed for 60 minutes at 70°C before completion. The blue colored cotton wool was separated by filtration using a Buchner funnel and placed in 900 ml of water containing 1.8 g of "Monogen" (a detergent, sodium alkylbenzene sulfonate). The saponification was carried out for 5 minutes at 100°C. The soap treatment was carried out for 5 minutes at 100°C. The cotton was separated by filtration using a Buchner funnel, rinsed well with water and dried. The cotton was then washed in sequence with dimethylsulfoxide, methanol-concentrated hydrochloric acid (volume ratio 50:1), methanol-concentrated ammonia water (volume ratio 50:1) and methanol, until the washing liquids produced no color effect. The cotton was then dried.

The blue pure cotton thus obtained was subjected to analysis for its copper content using the method of atomic absorption spectroscopy. The copper content was 0.065%. Consequently, 1 g of the cotton should contain 1.0 x 10<-6>mol phthalocyanine units. This material is hereinafter referred to as "blue cotton A".

Reference ( 2)

1 liter of water, 25 g of anhydrous Glauber's salt and 1 g of CI. Direct Blue 86 ("Sumilight Supra Turquoise Blue G conc") was placed in a 2 liter container and solution was provided by stirring. Then 50 g of cleaned cotton was immersed in the thus prepared dye bath and the temperature was maintained at 95°C for 60 minutes under stirring.Then the cotton was rinsed with water and dried to obtain a blue-colored cotton (hereinafter referred to as "blue cotton B).

Reference ( 3)

100 parts CI. Kype blue 29 ("Nihonthrene Brilliant Blue 4G Paste") and 1 part sodium alginate were added to water to form 100 parts of a dye bath. A cotton cloth was immersed in this dye bath and pressed to 60% press amount and then dried in hot air at 105°C

Separately, 60 parts "Hydrosulfite Conc", 30 parts caustic soda and 60 parts sodium chloride were dissolved in water to form a bath containing 1000 parts. The cotton cloth to which the dye was attached was immersed in the bath and then pressed to 120% pressure amount. A steam treatment was then given for 30 seconds in 105°C saturated steam to effect a reduction dye. After water rinsing, the thus treated absorbent cloth was subjected to oxidation ion treatment at 50°C in 1000 parts of a bath prepared by dissolving 10 parts of hydrogen peroxide (35%) and 10 parts of acetic acid (48%) in water. It was then subjected to soap treatment for 5 minutes at 95°C in 1000 parts water containing 3 parts "Monogen". The cloth was again thoroughly rinsed with water and dried to obtain a blue colored cotton cloth (hereinafter referred to as "blue cotton cloth").

Reference ( 4)

1 liter of water, 25 g of anhydrous Glauber's salt and 1 g of CI. direct blue 86 ("Sumilight Supra Turquoise Blue G Conc") was placed in a 2 liter container and the mixture was stirred to dissolve. Then 50 g of a nylon fiber was immersed in the dye bath, and 0.5 acetic acid was added. The temperature was maintained at 95°C for 60 minutes with stirring. Then, water was squeezed out to obtain a moist blue colored nylon fiber (hereinafter referred to as "blue nylon").

Reference ( 5)

200 g of copper phthalocyanine, 1200 g of sodium chloride and 350 g of diethylene glycol were placed in a kneader, and the mixture was ground for 6 hours. The ground contents of the kneader were placed in 5 liters of water, and the undissolved part was separated by filtration, rinsed with water and washed with various solvents. The thus powdered copper phthalocyanine had a surface area of 58 m 2 /g (BET method by nitrogen absorption), and was very effective for the absorption of harmful substances (hereinafter referred to as "pigment").

Example 1

Using each of the materials obtained in the above references, a tobacco filter was prepared and this was packed in a glass tube with an inner diameter of 8 mm and a length of 15 mm. The thus prepared glass tube with a filter was attached to a smoking device with a constant flow rate. The experimental results obtained are shown in Table 1. The results show that the filter is effective for the selective removal of mutagens compared to the case where no copper phthalocyanine compound was present in the filter.

1 table above, the removal ratio for tar, the removal ratio for mutagens and the suction resistance were measured using the following methods. When using a smoking device with a constant flow rate, smoking was carried out under such conditions that the smoking period is 2 seconds per suction with intervals between suctions of 40 seconds, the smoke length is 50 mm and the smoke flow rate is 16 ml/sec. The main smoke streams from 4 pipes were collected with a Cambridge filter CM 113, and the amount of tar was measured using a weight method.

The measured value is the average value of 20 cigarettes, and the third digit of the actual value was rounded by counting fractions of 0.5 and above as a unit, and discarding the rest. The removal rate of mutagens was measured by the mutagenicity obtained by the Ames test. The strain used in the test was TA 98 and the number of revertant colonies was measured with a tar ratio captured in the Cambridge filter of 300 my g/plate S9: my l/plate. The suction resistance was measured against the flow at a flow rate of 20 ml/sec. using a flow-through resistance meter.

Example 2

A tobacco filter was prepared with each of the materials obtained in the above reference examples and a strong water absorbent material. It was packaged in a glass tube with an inner diameter of 8 mm and a length of 15 mm. The thus prepared glass tube with the filter was attached to a smoking device with a constant flow rate. The obtained results are shown in Table 2. The results indicate that all the cases have efficiency with respect to the selective removal of mutagens, compared to the case where no copper phthalocyanine compound was present.

In the table above, the methods used for measuring the removal ratio for tar, the removal ratio for mutagens and the suction resistance were the same as those used in example 1.

Claims (12)

1. Tobacco filter, characterized in that a phthalocyanine compound, with or without a strong water-absorbing material, is present in the filter material. 2. Tobacco filter according to claim 1, characterized in that the phthalocyanine compound is a water-soluble copper phthalocyanine compound. 3. Tobacco filter according to claim 1, characterized in that the phthalocyanine compound is adhered or chemically bound to the filter material. 4. Tobacco filter according to claim 1, characterized in that the filter material is a substance containing hydroxyl or amino groups. 5. Tobacco filter according to claim 1, characterized in that the filter material is a polyhydroxy compound or a derivative thereof. 6. Tobacco filter according to claim 1, characterized in that the phthalocyanine compound is a reactive dye. 7. Tobacco filter according to claim 1, characterized in that the phthalocyanine compound is a copper phthalocyanine compound. 8. Tobacco filter according to claim 1, characterized in that the highly water-absorbing material is a water-absorbing polymer compound. 9. Tobacco filter according to claim 1, characterized in that the highly water-absorbing material is a water-absorbing polymer which is a polymer electrolyte containing carboxylate salt groups. 10. Tobacco filter according to claim 1, characterized in that the highly water absorbent material is a cross-linked sodium polyacrylate. 11. Tobacco filter according to claim 1, characterized by water being present in the filter material. 12. Cigarette holder for smoking tobacco, characterized in that it includes a filter according to claims l-ll.