Method of preparing open-cell foamed material

FIELD: polymer materials in tobacco industry.

SUBSTANCE: invention relates to foamed material constituted by cross-linked amino-formaldehyde polymer product suitable for filtration of tobacco smoke. Foamed material according to invention contains cavities and intermediate spaces located outside of cavities, said spaces being confined by walls consisted of cross-linked amino-formaldehyde polymer product optionally supplemented by additives. Average space dimension lies within 30 to 350 μm. Considerable portion of spaces have two or more perforations with average diameter within a range of 5 to 300 μm in their walls while considerable portion of perforations of neighbor spaces are arranged relative to each other in such a way as to form continuous nonlinear path. Foamed material is characterized by porosity at least 45 vol % and specific surface area 0.1 to 15 m²/g. Method of preparing of such foamed material comprises following stages: mixing air and foaming agent solution under pressure in mixing zone of injector filled with multiple inert mixing members; passing, under pressure, non-hardened foam from mixing zone and prepolymer solution into reaction zone of injector to form curable foam; and discharging foam and drying it in air. Use of such foamed mixture as cigarette filter allows content of toxic compounds such as resins and polycyclic aromatic compounds to be lowered.

EFFECT: enhanced tobacco smoke filtration capacity.

6 cl, 10 dwg, 6 tbl

This invention relates to a foamed material, it is suitable for cleaning and filtering of air, especially filtering toxic compounds, such as, for example, tar and polycyclic aromatic hydrocarbons (PAH) from tobacco smoke, and to a method for producing such a foam material.

The most important filter material used in the world for the purification and filtration of tobacco smoke, is cellulose acetate, which can be used in conjunction with activated carbon or without it.

Conventional filter materials, such as cellulose acetate and activated carbon, have the disadvantage that it does not remove a significant portion of toxic compounds, such as tar and PAH present in tobacco smoke.

Moreover, in the patent description UK GB 755057 described cigarette filter, which is formed from urea-formaldehyde foam material having a thin instructure containing cavities, which are connected to each other so that tobacco smoke can flow through them, resulting in a filtering effect with respect to tar and nicotine present in the smoke.

Foamed material according to CB 755057 get first foaming capable of foaming liquid by the injection of air into it or mixing. Then foamed liquid is rawresult in a solid foam by mixing carbamidomethylated and a suitable catalyst with a liquid. After that, the resulting foam is treated with excess aqueous urea solution, to thus eliminate the smell of formalin.

Then the foam is treated with urea solution, is subjected to the compression process in order to increase the mechanical stability of the foam and at the same time, to ensure that some hollow space will remain interconnected. Thus, according to GB 755057, get a foamed material having skeletton fine structure and a complex shape containing a large number of streams, with relatively low hydraulic resistance and significantly improved mechanical resistance. The specified fine structure filters aerosol particles, which are transferred together with the smoke.

The disadvantage of this method for GB 755057 is that in the first stage, i.e. when foaming is able to foam the liquid, the mixing occurs in poorly controlled conditions. As a result, it is impossible to get the foam is quite certain structure under strictly controlled conditions.

Indeed, the structure of the foamed material is important for the filtering effect of tar and nicotine from tobacco smoke. According to the applicant, the structure of the foamed material obtained by the method according to GB 755057, is not efficient enough to filter out tar and nicotine of the tab is knogo smoke. For example, this structure actually contains a cavity, but it includes a closed cavity, which is not available for aerosol particles carried along with the smoke.

Another disadvantage of the method of retrieval GB 755057 is that after receiving the foam-based carbamidoformaldegid specified foam is required to be compression process in order to obtain a good foam filter material for cigarette filter by destruction of the walls of the cavities.

In addition, in the patent description Italy IT 574416 describes a method for filtering mass on the basis of urea resins to remove nicotine and tar and other products from tobacco smoke. In the specified way of a mixture of urea-formaldehyde solution, foaming agent, acid and finely powdered gel SiO₂mix to create a rich foam, which is then cured and dried. Gel SiO₂is a well linking nicotine agent.

The disadvantage of IT 574416 is that the gel SiO₂must be used to achieve a sufficient filtering effect of the final foamed product. Another disadvantage is that the mixing takes place in poorly controlled conditions, so that, as in the way of getting GB 755057, it is impossible to obtain a foam with a specific structure.

Unexpectedly, this task is achieved by creating a foamed material containing cavity and the intermediate space located outside of the cavity, the cavity is limited by walls, wall cavities formed crosslinked polymer and possible additives, with an average maximum size of the cavities is in the range 30-350 μm, with a significant portion of the cavities has two or more perforations in their walls, the perforations have an average diameter in the range 5 are 300 μm, a significant portion of the perforations adjacent cavities located with respect to each other so as to form a continuous non-linear trajectory, and the foamed material has a porosity of at least 45 vol.%, porosity is defined in volume% of the total volume of foam material, the part of the foamed material suitable for the passage of substances through the foam material, the foam material has a specific surface area in the range of 0.1-15 m²/year

Foamed material according to the invention has the advantage of it has such a structure that the toxic compounds in tobacco smoke can be filtered to a high degree. An advantageous application of the foamed material, the filtering material is further explained below.

Brief description of figures

The invention will now be described based on the accompanying drawings, where:

Fig. 1 is obtained scanning electron microscopy (SEM) image of foamed material according to this invention (increase 90s),

Fig. 2 - SEM image of the filter material based on cellulose acetate (magnification 200x),

Fig. 3 - SEM image of foamed material on the basis of urea-formaldehyde according to GB 755057 (increase K),

Fig. 4 - SEM image of a particular variant of foamed material according to the invention (increase K),

Fig. 5 - SEM image of another variant of foamed material according to the invention (increase K),

Fig. 6 is a schematic view of the injector, which can be used to obtain a foamed material according to the invention,

Fig. 7 shows two different cross-section of the injector that is used to obtain foamed material according to the invention, where Fig. 7B shows a cross-section that is perpendicular to the line a-a' in Fig. 7A,

Fig. 8 shows a testing device used for testing Phi is trow tests in a continuous area, containing foamed material according to the invention or cellulose acetate,

Fig. 9 shows the testing device used for testing intermittent smoke filters containing foamed material according to the invention or cellulose acetate,

Fig. 10 shows the results for the removal of resin through the filter of cellulose acetate filters and containing foamed material according to the invention.

Three-dimensional color images corresponding to Fig. 1-5, and 3M-sight are open for review at the office where filed this application.

Detailed description of the invention

The structure of the foamed material according to the invention is described with reference to Fig. 1. Fig. 1 refers to the SEM image, which shows the structure in the three-dimensional image.

The structure of the foamed material according to the invention, on the one hand, contains a cavity surrounded by walls, and, on the other hand, the space located outside the cavities, so-called intermediate space.

In the prior art foaming these cavities are referred to as "bubbles", "cell", "sphere" and the like. Cavity foam material according to the invention often do not have the ideal shape of a sphere. For example, they may have also ellipsoidal, spheroidal, or other thermodynamically favorable form.

The walls of the cavities comprising the of the cross-linked polymer and possible additives. In the prior art cross-linked polymer is called as "net polymer. Preferably cross-linked polymer is a synthetic organic copolymer, such as, for example, a copolymer on the basis of urea-formaldehyde. Crosslinked polymer, however, can also be polyurethane.

A significant portion, preferably more than 90%, of the walls of the cavities of the foam material according to the invention contains two or more perforations. In the technique of such perforated cavity are referred to as "open cell", "open", "pores" and the like. In addition, cavities that do not have perforations, referred to as a "closed cell", "private sphere" and the like. The percentage of closed cavities in the foam material according to the invention is relatively small, preferably less than 10%. Most preferably the foam material also contains a low percentage of cavities, which have only one perforation such cavities limit the current to tobacco smoke through a filter containing foamed material.

The average maximum size of the cavities in the foam material according to the invention is in the range 30-350 μm, preferably 50-250 μm. Under the "max size" here refers to the longest distance from wall to wall inside the cavity.

The average diameter of the perforations in the walls of the cavities in the foam material according to the invention is within a 5 are 300 μm, preferably 5-200 μm, preferably 10-200 μm, and most preferably 10-100 μm. A significant portion, preferably more than 40%, and more preferably more than 80%, perforations adjacent cavities are located in relation to each other or connected to each other so as to form a continuous non-linear trajectory. Under the "continuous path" means that tobacco smoke can flow through the filter containing foamed material according to the invention, from the beginning to the end of the filter. Under "nonlinear trajectory" means that the specified flow path is not direct channel and winding path.

Not limited to any theory, it appears that aerosol particle, present in tobacco smoke, such as, for example, containing tar aerosol particle, the following continuous nonlinear trajectory, which is defined above, after crossing the first cavity may be slowed by collision with the wall of the next cavity. Tobacco smoke, which leaves a cigarette toward the bronchial tubes may contain 10⁹-10¹⁰containing resin particles per ml, varying in diameter from 0.1 to 1.0 μm (Baker, 1999). As a result, aerosol particle can stick to the wall in the next cavity. Therefore, aerosol particle fun what is a cavity. It is not excluded, however, that the aerosol particles may also be detained in the intermediate spaces.

As a quantitative indicator of the filtering effect of foamed material such as foamed material according to the invention, in respect of aerosol particles present in tobacco smoke, can be used permeability of foamed material. The specified permeability is determined by the filtering coefficient K.

The filtering coefficient K according to the relation Kozeny-Carman depends on the following three parameters:

K = f(1/k, ε³/(1-ε)², 1/(A_sp)²),

where k is a measure of sinuosity of the path of flow (or a factor of the maze), ε mean porosity and a_spmean specific surface area.

As can be seen from the ratio of the Kozeny-Carman shown above, the filtering effect is determined mainly by the porosity and specific surface.

The porosity of foamed material define here as the volume percentage based on the total volume of foamed material, the part of the foamed material, which is available for the passage of substances through the foam material. In the system consisting only of closed areas, porosity refers only to the intermediate spaces located outside areas. On the other hand, in the system consisting of only open what's fields, porosity refers to the intermediate spaces located outside areas and spaces within fields.

Porosity, which is defined above, can be measured by the saturation of the foam material, for example an organic solvent, such as hexanol. Then determine how large the mass and volume of solvent soaked foam material. The percentage specified a certain volume to the total volume of foam material is porosity as defined above.

The porosity of foamed material according to the invention as defined above and which is determined by the method described above is at least 45 vol.%. The preferred porosity in the range 45-99%. The preferred porosity of at least 60 vol.% or in the range of 80-99%vol.

The specific surface foam material according to the invention is 0.1-15 m²/, Preferred specific surface area in the range 3-15 m²/g Specific surface area determined by adsorption of nitrogen gas at -196°according to the well known BET method developed by Brunauer, Emmett and teller.

The above quantitative parameters are the parameters by which it is possible with absolute certainty to predict the filtration efficiency and the CT foamed material according to the invention for aerosol particles, present in tobacco smoke. All the properties of foamed material, and those that can be expressed only in a qualitative sense, and those that can be expressed in quantitative parameters that contribute to the specified filtering effect. The actual filtering effect of foamed material according to the invention is determined by carrying out tests on Smoking (see examples of tests).

The following are other properties of foamed material according to the invention.

The structure of the foamed material according to the invention is characterized by the absence of order. This means that the size distribution of cavities in the inner structure is the same. The specified distribution is erratic distribution. This means that there is no system in the size distribution of cavities. For example, not all cavities of equal size in their largest dimension, as defined above. On the contrary, the specified maximum size varies from 30 to 350 μm. So here it is named as "average" maximum size.

What is said in relation to the distribution of the largest dimension of the cavities, also suitable for distribution in the internal structure of the diameters of the perforations present in the walls of the cavities. Here he is called "average" in diameter.

The form of these perforations, as a rule is, can be characterized by the ratio length/width. The shape of the perforations in the cavities of the foam material according to the invention can vary from round (isodiametric) to the corner. In addition, the ratio of length/width of these perforations may be such that the question may arise about the form of perforations "burst-like" ("like an explosion)".

The specific gravity of foamed material according to the invention in the dry state may be in the range of 5-100 kg/m³. Specific gravity in the range 5-60 or 10-30 kg/m³the preferred. The preferred specific gravity in the range of 10-50 kg/m³.

The structure of the foamed material according to the invention is also determined by the method of its production, in particular by way of mixing with foaming foaming agent. In the specified mixing mode, where the air is mixed with the blowing agent, use a variety of inert mixing elements having a specific size. As the inert mixing elements can be used spherical glass mixing elements, such as glass beads.

When using relatively small balls, according to the invention receive a foamed material, the SEM image of which is shown in Fig. 4 (ball diameter = 4 mm). It is evident from Fig. 4 it is obvious that the relative share of perforations in the surface the five walls of the cavities is relatively small.

When using relatively large balls, according to the invention receive a foamed material, the SEM image of which is shown in Fig. 5 (the ball diameter = 10 mm). It is evident from Fig. 5 it is evident that the relative share of perforations in the surface of the walls of the cavities is relatively high.

According to the applicant, when using balls having a relatively great diameter, for example greater than 15 mm, cavity any punching largely with the formation of very thin foam. Thin foam - the foam walls of cavities which are not self-supporting. The mechanical stability of such a foam material is relatively low. In addition, the reduced specific surface area. The porosity remains almost the same. When using the balls are relatively very small diameter, for example less than 2 mm, the opposite effect occurs, it is clear that the porosity remains almost the same.

The following describes a method that can be used to obtain a foamed material according to the invention.

In the specified method using the injector, which is shown schematically in Fig. 6. In the prior art, this injector is also known as the injector tube.

In the mixing zone 7 of the injector at a certain pressure to deliver air through the inlet 2 and the Venturi tube 4 and through the inlet 3 and the cutting Venturi serves 6 a solution of foaming agent. The mixing part 7 is filled with many inert mixing elements having dimensions in the range of 2 to 15 mm (not shown in Fig. 6). As described above, in an inert mixing elements can be used spherical glass mixing elements, such as, for example, glass beads. Preferably use glass beads having a diameter ranging from 4 to 10 mm

In the mixing zone 7 a solution of foaming agent foams, so that the formed uncured foam. This foam is directed into the reaction zone 8. At the same time in reaction zone 8 via the inlet 1 and the Venturi tube 5 serves the solution of the prepolymer at a particular pressure. In the mixing zone 7 may be filed with the catalyst of the crosslinking or polymerization, such as, for example, an acid catalyst, preferably together with a solution of foaming agent.

As a "prepolymer" can be used, for example, urea-formaldehyde precondensed or, for example, reagents that form the polyurethane. When using a solution of urea-formaldehyde pre-condensate, in this solution is preferably introduced an additional amount of urea (see also GB 755057, discussed above). Ismanam number of additional urea can be brought to the desired density values is here and fragility foam material.

It is preferable to apply the solution of foaming agent and the solution of the prepolymer in the injector at an equal flow rate (flow rate), i.e. when the volume ratio between the two solutions of 1:1. These solutions may not necessarily contain additives, such as additives for improving the foaming properties of the solution of foaming agent and/or additives, such as surfactants, to improve the adsorption properties of foamed material in respect of the substances present in the molecular gas phase. Other possible additives, for example, to improve the adsorption properties are fillers and pigments, such as, for example, silica gel, titanium oxide, activated carbon and the like.

In the reaction zone 8 is the reaction of copolymerization, by means of which forms a cross-linked polymer or a mesh polymer. Uncured foam makes in capable of curing the foam by the reaction. The specific structure of the foam, which is formed in the mixing zone 7 and the reaction zone 8, then fix.

Capable of curing the foam formed in the reaction zone 8, finally leaves the injector through the outlet 9, at this moment capable of curing foam meanwhile, may be partially utverzhdenii. After this the foam is dried in air and not necessarily sleduyushim by heating at a temperature of about 40° With so formed completely cured foamed material, and a small residual amount of polyformaldehyde, which are still present in it, are removed.

Foamed material according to the invention can be crushed into powder. Preferably, this powder has a particle size in the range from 0.1 to 2 mm.

The powder may be included in the filter as a filter material for filtering or purifying air in order to remove contaminants, such as toxic compounds from the air. Instead of unground powder foamed material, as such, may also be included in the filter as the filter material.

In addition to the foamed material or the powder according to the invention the filter, as defined above, may also contain organic polymer fibers, such as, for example, cellulose acetate.

In addition, the cigarette containing the hookah and the tobacco column, and where the mouthpiece filled with filter material, foamed material or the powder according to the invention can be used as a filter material, optionally in combination with an organic polymer fibers, such as, for example, cellulose acetate. This cigarette filter is used to filter out tar and nicotine and other toxic compounds like PAH from tobacco smoke.

EXAMPLES

P is the iMER 1

In order to obtain a foamed material according to the invention, a separately prepared liquid a and B.

The liquid And is prepared by mixing 25 kg water-soluble urea-formaldehyde precompensate (Basopor® 293 Pulver, available from BASF Nederland B.V.), 10 kg urea and 100 liters of water with stirring for 2 hours at 35°C.

The fluid is prepared by mixing 5.5 liters foaming agent (Basomol® 514 flüssig, available from BASF Nederland B.V., which is an aqueous solution containing 25% by weight of phosphoric acid and less than 10% by weight of resorcinol and having a pH 1-2) and 100 liters of water with stirring for about 30 minutes at 35°C.

In order to obtain a foamed material according to the invention, sequentially apply the injector, as shown in Fig. 7, the main operation of which is discussed above in connection with Fig. 6. Digital designations indicated in Fig. 7, have the same meanings as in Fig. 6. The mixing zone in Fig. 7 filled with glass beads having a diameter of approximately 7 mm

In the mixing zone 7 at a temperature of about 35°served With the fluid under pressure of 11.5 bar and at a flow rate of 10 liter/minute through the inlet 3 and the air pressure 5.5 bar through the inlet 2. When mixing receive the uncured foam, which is then sent to the reaction zone 8,which simultaneously through the inlet 1 serving liquid And under pressure of 11.5 bar and at a flow rate of 10 liter/minute. In the reaction zone 8 is the rapid reaction of copolymerization at a temperature of about 35°With that catalyze the acid catalyst present in the liquid, so get capable of curing the foam.

The foam, which may be partially utverzhdenii, discharged through the outlet 9 at atmospheric pressure, air-dried and then heated at a temperature of about 40°With, so get fully cured light-colored foamed material. After that cured foamed material is crushed into powder.

Get SAM image and powder, and dried and then heated foamed material. SEM images and powder, and foam material find similar patterns. SEM image of foamed material shown in Fig. 1.

Thereafter, determine some quantitative parameters of the foam material, and the parameters that determine, and the way they are determined, as described above.

The foam material has an average maximum size of the cavities of about 275 microns. Perforations in the walls of the cavities are essentially round and have an average diameter of approximately 250 μm. Moreover, the foamed material has a porosity of about 65%, specific surface area of approximately 0.8 m²/g and the specific mass is approximately 20 kg/m ³. Other properties of the structure of foamed material in a qualitative sense discussed above.

Example 2

In this example, use the method described in example 1, except that upon receiving the liquid And use 2 kg of urea, and that upon receipt of fluid In use 115 liters of water.

Thus obtained foamed material has an average maximum size of the cavities of about 275 microns. Perforations in the walls of the cavities are essentially round and have an average diameter of approximately 100 μm. Moreover, the foamed material has a porosity of approximately 97%, the specific surface of approximately 12 m²/g and the specific weight of approximately 20 kg/m³. Other qualitative properties of the structure of foamed material discussed above.

Example 3

In this example, preparing a polyurethane foam as the foam material according to the invention, using the method described in example 1.

Liquid a is an aqueous solution containing 25 kg of polyethylene glycol (molar mass about 1000 g/mol), 9 kg of hexamethylenediisocyanate and 0.1 kg of triethylamine as a catalyst. Liquid is an aqueous solution containing 2 kg of 1,4-butanediol, 0.4 kg 1,2,5-hexanetriol and 0.1 kg of triethylamine as a catalyst. Liquids a and b have an equal volume of 100 liters. After this definition is given some quantitative parameters of foamed material, the parameters that determine, and the way they are determined, as described above.

The foam material has an average maximum size of the cavities is approximately 300 μm, it is in addition to the many intermediate spaces having a diameter between 200 and 275 μm, there are also large intermediate space having a diameter of about 1000 microns. Perforations in the walls of the cavities essentially have an elongated shape or form "burst-like", having an average length of about 80 μm and an average width of approximately 20 μm. These perforations why have an average diameter of 80-20 μm. Moreover, the foamed material has a porosity of approximately 52%, the specific surface of approximately 4 m²/g and the specific gravity of approximately 48 kg/m³. Relatively low porosity value indicates that this foamed material contains a considerable number of closed cavities.

Comparative example 1

In this comparative example, the gain of urea-formaldehyde foam, using the method described in GB 755057.

Get SEM image of the foam thus obtained, which is shown in Fig. 3.

Thereafter, determine some quantitative parameters of the foam material, the parameters that determine, and the way they are determined, as described above.

The foam material has the highest average size of the cavities is approximately 35 μm, it in addition to the prevailing spaces having the largest size in the range of 30-50 microns, are also very large space, with the largest size in the range of 600-700 microns. In addition, the foam material has an average diameter of the perforations is approximately 30 μm, with the proviso that there are very few perforations in the walls of the cavities, so no question about the spatial continuum. This means that in the foamed material obtained in this comparative example, only a very few perforations adjacent cavities are located in relation to each other and connected to each other to form a continuous non-linear trajectory, as it actually happens with foamed material according to this invention. Finally, the foamed material has a porosity of approximately 50 vol.%, the specific surface of approximately 7 m²/g and the specific gravity of approximately 80 kg/m³.

Thus, the structure of the foamed material prepared in this comparative example differs from the structure of foamed material according to the invention, as, for example, about the extent of perforated cavities, which have already been discussed above.

Comparative example 2

To compare the structure of the foamed material according to the invention with the structure of cellulose acetate, which is used as filter material in a commercially available cigarette filters, the obtained SEM image of the specified cellulose acetate, which is shown in Fig. 2. It is evident from Fig. 2 shows that the cellulose acetate of these cigarette filters is disordered fibrous structure, which is clearly different from the structure of the foamed material according to the invention, which contains a perforated cavity.

Examples test

Test methods

Cigarettes

Experiments with tobacco smoke carried out with commonly available in retail locations cigarettes with filters, forming 12 mg tar and 0.9 mg of nicotine, as indicated on the package. The mouthpiece, which the cigarette is supplied during its production, consists of a filter of 120 mg of cellulose acetate (hereinafter referred to as "CA") in a paper wrapper. SA filter removed from the paper wrapper with a pair of tweezers and partially replaced by powder foam material according to the invention, such as powder foamed material obtained in example 1 (hereinafter referred to as "the filter material of cross-linked polymer" or "NP material"), or powder foamed material obtained in example 3 (hereinafter referred to as "PU material").

Moreover, NP or PU material may be manually chopped grated (through holes of a grater 1.6-1.8 mm), then dried in air for 16-20 hours at 40°and placed in a new paper envelope between the tobacco rod and reduced by half (60 mg) CA f what ltram in the mouthpiece. The mouthpiece supply of cigarette filters with 15 or 30 mg, respectively, cross-linked polymer or 15 mg PU material. These filters hereinafter referred to as NP-15 or NP-30, respectively, or PU-15. These cigarettes with filter compared with the samples, the filter of which the mouthpiece (120 mg SA) is left completely intact. The specified filter is hereinafter referred to as "SA".

The experiments area

Cigarette filters experimentally smoke, creating conditions for continuous and discontinuous area with facilities for testing, described below.

Continuous Smoking

In the study of the effect of continuous Smoking cigarettes with filters placed in the installation for testing, shown in Fig. 8, which consists of the following parts: water pump, flow meter, pressure gauge and absolute filter.

On the suction side of the waterjet pump is combined with an artificial tip in the form of a hose made of butyl rubber having an inner diameter of 8 mm, suitable for used cigarette filter.

Using a flow meter (Sho Rate model 1355, Brooks Instruments BV, Veenendaal) the flow rate of air support 250-330 ml per minute with an average period of combustion of 4.0-4.5 minutes and the residual tobacco rod 3-5 mm above the filter (some experiments carried out at 500 ml per minute).

Absolute filter and pressure gauge is placed between the mouthpiece and the flow rate of the mayor. Absolute filter consists of a detachable glass container with 200 mg NP in it, which, as you can assume, it is sufficient to remove all particles from tobacco smoke. With this filter you can determine the amount of resin which passes through a cigarette filter, which can be quantified as the smoker is exposed to the resin.

Intermittent Smoking

The standard procedure for determining the content of tar in cigarettes during intermittent mechanical area initially developed in the nineteen thirties (Bradford, 1936). In 1969, the specified method is adopted as a Directive 60/2/35 Federal trade Commission (FTC) and since then used as an institutionalized standard instructions (Pillsbury, 1969). This research uses the method specified by the FTC. 35 ml of air to be sucked in for 2 seconds with a frequency of once per minute.

Installation for testing used in intermittent Smoking, shown in Fig. 9. In these experiments use the burning period of 6 minutes, resulting in an average residual tobacco rod 3-5 mm above the filter. In experiments using a syringe for injection capacity of 50 ml, which through the cigarette seven times suck in 35 ml of air that is released through the side opening. Used for cigarette mouthpiece of b is tilkowski, absolute filter and gauge are the same as in the tests described in the section entitled "Continuous Smoking."

From the literature (Djordjevic, 1997) it is known that the application of the method of the FTC on light cigarettes is no longer a pattern of behavior when Smoking. Smoking these cigarettes with a nicotine content is lower than 0.9 mg (as indicated on the package), in practice, can lead to more frequent puffs smokers. As a result, the impact of tar in the bronchial tubes of the smoker becomes higher than indicated on the package. For this reason, it is important to understand the activity of the NP filter in the case of increasing the number of puffs per minute.

In this study, for this reason, the reduction of tar when smoked under standard FTC Directive (60/2/35) compared with a decrease at twice (referred to as the Directive FTC 30/2/35) and quadruple (referred to as the Directive FTC 15/2/35) frequency of puffs, respectively.

Determination of pressure drop across the filter

The average pressure drop across the cigarette filters when the test mode and continuous, and discontinuous area is measured by an electronic pressure gauge RS Components Ltd, Corby, Northans, UK). Here apply the buffer cylinder 120 ml, connected in series with a tobacco plant without the absolute filter. The specified cylinder supply plug from Buti is rubber and aluminum crimp cap, so the gauge can be attached via a needle for injection.

Determination of ash particles of combustion in the smoke after passing through the cigarette filter

Out of the smoke which passes through a cigarette filter, the filtered particles. Of these particles determine the ash of combustion. This is the case with filtered cigarettes, which are subjected to intermittent Smoking within 6 minutes according to the FTC Directive 60/2/35. The determination is carried out for three filtering systems: standard filter 120 mg of cellulose acetate (CA control), 15 and 30 mg of cross-linked polymer plus 60 mg SA. In determining the combustion ash used the flat filter (Whatman QM-A cross-section 37 mm), which brings together the solid phase. The increase in the mass of the flat filter is determined by weighing after 16-20 hours drying at 40°C.

Determination of resin

Tar from tobacco smoke is extracted with organic solvents sequentially from a cigarette, butyl rubber hoses and the absolute filter.

Sequential extraction of the cigarette and the absolute filter is conducted with a mixture of 20 ml of 96% ethanol, 20 ml of hexane and 40 ml by volume of acetone. The extraction is carried out in vessels (136 ml) with a screw cap fitted with silicone plug cap with Teflon coating. Butyl rubber mouthpiece, into which is inserted a cigarette in the experiments, raybaut three times with 1 ml of acetone in the same vessel with a screw cap, as an absolute filter.

After that vessels with a screw cap is placed on the shake tray (180 strokes per minute, amplitude 5 cm) for 30 minutes, the extracts filtered through a folded paper filter (Schleicher & Schüll roodband). The filtrate is collected in a porcelain tray (dia. 10 cm), the filter is successively washed with three times 20 ml of the same extraction liquid.

After 16-20 hours, the evaporation of the extraction fluid at 40°and weighting may be determined by the tar in a cigarette, thus take into account the amendment to nicotine (0.9 mg/cigarette) and clean the filter. It is assumed that the nicotine is completely or almost completely removed in absolute filter.

Determination of PAHs

Polycyclic aromatic hydrocarbons measured in tobacco smoke that passes through the cigarette filter. Cigarette smoke filters for 4.0 to 4.5 minutes in continuous area when the air flow rate 500 ml/min

Explore three of the filtration system: standard filter 120 mg of cellulose acetate (CA control), 15 and 30 mg of cross-linked polymer (NP) each time with 60 mg SA. Suction tobacco smoke consistently lead through the flat filter (Whatman QM-A 37 mm) and adsorption structure XAD-2 after passing through the three filter system.

Thus can be implemented division in tobacco smoke between the PAH in the particulate (associated particles) phase and PAH in the gas phase (Chuang and others, 1990).

The flat filter and adsorption structure XAD-2 extracted with methanol and dichloromethane, respectively. After evaporation under nitrogen atmosphere extract dissolved in 1 ml of acetonitrile. Analysis of the PAH mixture is conducted through GHUR. For calibration used here the standard mixture with 16 PAH according to the Directive Department for environmental protection (EPA).

Determination of nicotine

After passing through the cigarette filter measure nicotine in tobacco smoke filtered cigarettes, which are subjected to intermittent Smoking within 6 minutes according to the FTC Directive 60/2/35.

Explore three of the filtration system: standard filter 120 mg of cellulose acetate (CA control), 15 and 30 mg of cross-linked polymer (NP) each time with 60 mg SA.

Nicotine is associated with particles or molecular present (not linked) in the gas phase, concentrate on the flat filter (Whatman QM-A 37 mm) and adsorption structure XAD-4, respectively. Thus can be implemented division in tobacco smoke between nicotine-related particles and nicotine present in the molecular gas phase (Chuang and others, 1990). For analysis of nicotine by gas chromatograph and a flat filter, and the adsorption structure XAD-4 is extracted with ethyl acetate under the influence of ultrasound (35 kHz, 15 minutes).

the pH of cigarette smoke to determine, using about iannou above the continuous area, equipped with bromyalgia gas, but without a flow meter, pressure gauge and absolute filter. After absorption of cigarette smoke from three cigarettes in prominance gas 250 ml, filled with 100 ml of demineralized water, measure directly the pH of the liquid. The specified pH is defined as pH of cigarette smoke.

Determination of the toxicity of cigarette smoke

The General toxicity of smoke cigarettes with filter after passing through the mouthpiece determined by their area in intermittent mode within 6 minutes according to the FTC Directive 60/2/35 and collecting smoke. Specified General toxicity is determined for three filtering systems: standard filter 120 mg of cellulose acetate (CA control), 15 and 30 mg of cross-linked polymer (NP) each time with 60 mg SA.

When determining the overall toxicity use a glass container with 200 mg NP, which is collected smoke components after passing through the cigarette filter. The contents of the specified filter (200 mg NP) is extracted with acetone, with as for GHUR, as described in the section entitled "Definition of tar. These extracts are filtered through a filter of glass wool, evaporated in nitrogen atmosphere up to 2 ml and then stored in containers with a screw cap at 4°C.

As a measure of total toxicity determine the inhibition of energy metabolism in cells. Do with re-activated the mill is artimi cultures of Vibrio fischeri, bacteria that glow in well-functioning of the citric acid cycle. This method is carried out in 96-well tablet renewed according to the method (Hamers and others, 2000).

Determination of the toxicity of combustion gases of the filter material

The toxicity of the tested filtration systems as such (not exposed to tobacco smoke) are examined in orienting the experiment with the complete combustion of the filter material, including paper envelope.

Standard filter 120 mg of cellulose acetate (CA control) compared with 30 mg of cross-linked polymer (in this case, not in combination with 60 mg SA). Here apply butylcatechol mouthpiece, described in the section entitled "Continuous Smoking", and regulate the water-jet pump 20 liters of air per minute.

After manually igniting the lighter gases of combustion both filter materials absorb in prominance gas with a capacity of 250 ml, filled with acetone, with as for GHUR, or demineralized water (in both cases, 50 ml). Both the absorption liquid is filtered through glass wool and stored in containers with a screw cap at 4°C. as a control in the analysis of V. fischeri is the surrounding air, heated by the lighter, which after transmission within 5 minutes (a total of 100 liters of air) absorb both liquids.

Analysis of DR-CALUX

Analysis of the expression of the chemically activated luciferase (CALUX) for substances that activate the receptor dioxin (DR)is a new type of in vitro bioanalysis, allowing quick and precise quantification of specific toxicity of PAH and dioxin in the mixture of compounds (Murk, 1998). They use a line of tumor cells of the rat liver, which as a reporter for the activation of the dioxin receptor introduced gene, which encodes a luciferase derived from fireflies.

Analysis of DR-CALUX carried out with the smoke from filtered cigarettes that burn intermittently for 6 minutes, according to the FTC Directive 60/2/35.

Explore three of the filtration system: standard filter 120 mg of cellulose acetate (CA control), 15 and 30 mg of cross-linked polymer (NP) each time with 60 mg SA. Particulate phase of tobacco smoke through the cigarette filter concentrate in a glass container containing 200 mg NP. The contents of the specified filter (200 mg NP) is extracted with acetone, with as for GHUR, as described in the section "Determination of tar.

These extracts are filtered through a filter of glass wool and then evaporated in nitrogen atmosphere up to 2 ml and stored in containers with a screw cap at 4°C. depending on the incubation period, quantify, mainly decomposable compounds like PAH, or only stable connection is which dioxin-like. Analysis of DR-CALUX carried out in a device for measuring luminescence with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a standard. Response CALUX convert to nanomoles TEQs (TCDD equivalents) per ml of purified extract.

Results

PU filter

Filter PU-15 works only 12% better than the filter SA in respect of the removal of the resin in the experiment discontinuous area, as described above in the section entitled "test Methods". Below we discuss results of tests of filters NP and CA.

Remove tar

For some experiments intermittent and continuous area with the ultimate absolute filter table. 1 shows the balance of the resin on all three filtration systems. Values are shown for each filtration system is the average of the five series six cigarettes (standard deviation of <10%). Table. 1 shows the resin content in milligrams per cigarette, measured in three filtration systems SA*, NP-15* and NP-30* after continuous and intermittent Smoking (FTC Directive).

Table. 1 shows that collecting resin NP filters better than in SA filter. Continuous Smoking increases the total content of the resin with respect to the method of the Federal trade Commission in 2,5-3 times. In both conditions the area is well feasible that NP filters with increased content of NP work much better than a standard filter SA.

As a result, the effect of the resin on the smoker decreases. The trays with the evaporated F. what litrato SA, NP-15 and NP-30 received FTC method shown in Fig. 10, well show it accurately. Fig. 10 shows a qualitative picture of the effect of the resin on the smoker in the form of the evaporated extract is derived from the absolute filter (after the passage of the mouthpiece). It refers to a series of three samples collected from the six cigarettes with filters, smoked under FTC method. Left to right: SA monitoring, NP-15, NP-30.

The amount of resin that passes through the filter during Smoking according to standard Directive FTC can be compared with the amount of resin which passes through when doubled and increased to four times the frequency of puffs, respectively, according to the mentioned Directive (see table. 2). The average periods of combustion here reduced from 6 to 5.5 and 4.5 min, respectively. In all cases, could be provided with a residual length of the column of tobacco 3-5 mm above the filter.

Values are shown for each filtration system is the average of the three series of six cigarettes (standard deviation of <8%). In table. 2 the content of the resin is shown in milligrams per cigarette for the two filtering systems SA* and NP-15* for intermittent area corresponding to one puff per minute by Directive FTC, in comparison with renewed and increased at four times the frequency of this Directive.

With an increased frequency of puffs (FTC4) filter efficiency of cross-linked polymer increases with a factor of 5. Moreover, 21 milligrams of tar per cigarette, passed through SA filter, three quarters higher than 12 milligrams, which is listed on the package.

The result produced is walking pressure changes, when increasing the frequency of puffs to two and four puffs per minute, increases the amount of tar in the smoke after SA filter (see table. 2).

NP filter seems more resistant to commonly occurring pressure changes than SA filter. The amount of tar in the smoke after NP filter does not depend on the frequency of puffs.

The pressure drop across the filter

For the consumer it is important to know whether the filter with improved removal of resin to create a too high pressure drop. The pressure drop measured on the filter for three filtering systems with intermittent Smoking for three filters SA, NP-15, NP-30 is equal to 70 mbar 70 mbar and 90 mbar, respectively. These values are average of two series of six cigarettes (standard deviation of <12%).

In continuous area average pressure drops significantly below. For CA and NP-15 filter found average 6 mbar, the pressure drop across the filter NP-30 was 9 mbar.

Ash combustion particles in the smoke after passing through the cigarette filter

Ash combustion of organic and inorganic particles that are present in tobacco smoke after passing through the filter is measured with intermittent Smoking. For the three filtering systems SA, NP-15, NP-30 ash of combustion after passing through the filter is 15, 4 and 1 mg/cigarette, respectively. Values are shown for each filter the overall system, are average of two series of six cigarettes (standard deviation of <12%).

Comparison with the values in the table. 1 shows that the amount of ash of combustion passing through the mouthpiece SA control, twice as much as the content of resin (7 mg/cigarette).

In addition to what has already been established to reduce the resin, the collection efficiency of combustion ash (particles) NP filters much better than the SA control.

Remove s

Removing polycyclic aromatic hydrocarbons from tobacco smoke through the filter of the cross-linked polymer are examined in terms of area. Values are shown for each filtration system is the average of three cigarettes. Table. 3 shows the sum of 16 EPA-PAHs (total RAS) and $ 6 carcinogens (s-RAS) in micrograms (µg) per cigarette, selected from the tobacco smoke in continuous area after passing through SA*, NP-15* and NP-30*.

Total RAS calculated by summing the 16 EPA-PAHs. Known Carcinogenicity 6 of these wounds, of which the two most carcinogenic of the RAS are present in tobacco smoke, namely benzo(a)pyrene and dibenzo(ah)anthracene (Hoffmann, 1997). C-RAS represent the sum of these 6 wounds.

Table. 3 shows that RAS in tobacco smoke SA filters are essentially (94%) the nature of the associated particles. This distribution of non-volatile RAS in the particle phase and molecular present in the gas phase of tobacco smoke corresponds, as mentioned in the literature (Liang and Pankow, 1996).

Two-thirds of total RAS in the control presents f is uoranthene and pyrene, present in the particle phase in the amount of 6.8 and 4.6 μg per cigarette, respectively. Naphthalene, generally 0.6 ág per cigarette, is the most volatile compound in the range of measured total RAS (see table. 3), and 80% of its molecular is present in the gas phase.

These three polycyclic aromatic hydrocarbons in relation to the concentration by weight, and the overall proportions are considered characteristic of tobacco smoke (Baker, 1999).

Benzo(a)pyrene and dibenzo(ah)anthracene are quantitatively the most important as carcinogenic RAS in tobacco smoke (Hoffmann, 1997). Both compounds are present mainly in the particle phase investigated tobacco smoke in the total amount of 0.4 and 1.6 microgame on a cigarette, respectively. When using the filter, NP-30 is a vast reduction (93%) of the total content of the RAS.

For filter NP-15 reduced levels of total RAS is 65%.

These results are in good agreement with values remove tar, found in the continuous area (see table. 1).

Reduction of resin filters for NP-30, NP-15 is 95 and 86%, respectively.

Mass number of RAS is within such limits micrograms, it is approximately 0.1% of the mass of the resin (in milligrams) on the cigarette.

Comparing with each other the values shown in the of the GLA. 3, makes clear that for subjects filtering systems the concentration of total volatile RAS in the gas phase (after passing through the filter) remains the same. Adsorption of volatile wounds from the gas phase of tobacco smoke surface crosslinked polymer does not occur, or it is too difficult.

Remove nicotine

The adsorption of nicotine crosslinked polymer are examined in the experiment intermittent Smoking. Table. 4 shows measurements of nicotine that were made for filters NP-15 and NP-30. Values are shown for each filtration system is the average of the four cigarettes smoked under FTC method. In table. 4 shows nicotine (mg/cigarette)associated with particles in tobacco smoke and molecular present after passing through three different filtration system (SA*, NP-15* and NP-30*), respectively.

Because of the good separation of the particles of crosslinked polymer unexpectedly also functions effectively as a filter material for nicotine in tobacco smoke. The concentration of nicotine in the phase of tobacco smoke particles, shown in the table. 4, are falling sharply increasing mass filter NP. The number of molecular presence of nicotine may be low, but is permanent. Adsorption of molecular nicotine present surface crosslinked polymer, similar to PAHs, not happening, or it is too difficult.

The General toxicity of cigarette smoke after passing through filter

The tar in cigarette smoke is a complex composition of compounds, a clear impact on the health of the individual smoker is not easy to define. To get the value of the overall toxicity of the resin obtained in the experiments area, rapid method, using analysis of V.fischeri.

Moreover, inhibition of light output from the tobacco smoke passing through the filter with crosslinked polymer and cellulose acetate, respectively, Express the given light output during the test procedure with ozdogan (see table. 5). Values are shown for each filtration system is the average of the two series of six cigarettes. Table. 5 shows the General toxicity, identified by the analysis of V.fischeri and analysis of DR-CALUX, for the three filtering systems (SA*, NP-15* and NP-30*) in the intermittent mode area.

General toxicity in the table. 5 strongly decreases when the mass of NP in the filter NP increases. These data because of the chosen experimental setup consider only solid particles in tobacco smoke, which is collected after passing through the filter.

The contribution of compounds in the gas phase is not considered here, but he is only small, so you can neglect it. In table. 5 shows the magnitude of CALUX-TEQ combustion gases that pass through different filters. In the analysis of DR-CALUX conditions selected for pre-emptive measure the effects of wounds, rather than compounds such as dioxin. Here you can see that the number of RAS-specific toxicity decreases drastically when the number of NP in the filter material increases.

The contribution itself crosslinked polymer in General and specific toxicity seems to be negligible in these experiments. Extraction unloaded filter NP-30 (without 60 mg SA) is the value of 0.6 nmol TEQ per ml of extract, is many times lower than the control sample complete procedure without Smoking in the table. 5.

The General toxicity of the combustion gases of the filter material itself

The advancement of the combustion zone in a cigarette at some point can lead to elevated temperature up to the critical value for the decomposition filter. To obtain quantitative values that gases generated during the combustion of filters which absorb demineralized water or acetone.

Control (blank) the breakdown is the absorption liquid after passing the ambient air. The values shown in the table. 6 for each of the filtration system is the average of two series of six burned filters. In this test, the General toxicity of 10 mg of cellulose acetate of the standard filter compared with 30 mg of cross-linked polymer, in this case, without 60 mg SA.

The combustion process of both materials was without flash temperature, in contrast to the filter NP filter SA spontaneously does not go out. In table. 6 shows the toxicity manually ignited cigarette filters (SA control and NP-30), which are not exposed to tobacco smoke.

Used as absorption medium acetone and demineralized water does not detect differences in relation to the combustion gases formed from the materials of the filters. From the data in the table. 6 shows that 30 mg of cross-linked polymer is not more harmful than 120 mg of cellulose acetate used ICA control. In the analysis of DR-CALUX burned control SA filter in both series showed a signal 10 times more than burnt NP filter. This means that the NP filter during combustion shows a lower RAS-specific toxicity. It remains for NP-15, NP-30 filters containing 60 mg SA in addition to the 15 and 30 mg NP, respectively.

Sources of information

1. Foamed material for filtering tobacco smoke, containing cavity and the intermediate space located outside of the cavity, while the cavity is limited by walls, the walls of the cavities consist of cross-linked polymer agents (the urea formaldehyde product and possible additives, the average maximum size of the cavities is in the range 30-350 μm, a significant portion of the cavities has two or more perforations in their walls, the perforations have an average diameter in the range 5 are 300 μm, a significant portion of the perforations adjacent cavities located with respect to each other so that it forms a continuous non-linear trajectory, and the foamed material has a porosity of at least 45%vol.the porosity is defined in volume% of the total volume of foam material, the part of the foamed material suitable for the passage of substances through the foam material, the foam material has a specific surface is between 0.1-15 m ²/year

2. Foamed material according to claim 1, where the average maximum size of the cavities is in the range of 50-250 microns.

3. Foamed material according to any one of the preceding paragraphs, where more than 90% of cavities contain two or more perforations in their walls.

4. Foamed material according to any one of the preceding paragraphs, where the perforations have an average diameter in the range of 5-200 μm.

5. Foamed material according to claim 4, where the perforations have an average diameter in the range of 10-100 microns.

6. Foamed material according to any one of the preceding paragraphs, where more than 40% of perforations adjacent cavities are located relative to each other so as to form a continuous non-linear trajectory.

7. Foamed material according to any one of the preceding paragraphs, where the foamed material has a porosity of at least 60 vol.%.

8. Foamed material according to claim 7, where the foamed material has a porosity in the range 80-99%vol.

9. Foamed material according to any one of the preceding paragraphs, where the foamed material has a specific surface area in the range 3-15 m²/year

10. Foamed material according to any one of the preceding paragraphs, where the cross-linked polymer is a synthetic organic copolymer.

11. The foam material of claim 10, where synthetic organic copolymer is a copolymer on the basis of urea-formaldehyde.

12. Foam is a material according to any one of the preceding paragraphs, where possible additive selected from the group consisting of surfactants, fillers and pigments.

13. Foamed material according to any one of the preceding paragraphs, where the specific gravity of foamed material in a dry state is in the range of 5-100 kg/m³.

14. Foamed material according to item 13, where the specific gravity of foamed material in a dry state is in the range of 10-50 kg/m³.

15. Foamed material for filtering tobacco smoke produced by a process comprising the mixing of the air and solution of foaming agent under pressure into the mixing zone of the injector and the mixing zone filled with inert mixing elements having dimensions in the range of 2 to 15 mm, so that the formed uncured foam flow under pressure of the uncured foam from the mixing zone and solution of the prepolymer containing aminoformaldehyde product in the reaction zone injector with the formation of capable of curing foam, discharge of foam from the injector and drying it in the air with the formation of the cured foam material.

16. Foamed material according to item 15, where many inert mixing elements is a lot of glass balls having a diameter ranging from 4 to 10 mm

17. Foamed material according to clause 16, where the diameter of the glass beads is equal to 7 mm

18. Foamed mA is aerial on any of PP-17, where a solution of the foaming agent is an aqueous solution containing phosphoric acid and resorcinol, and the solution of the prepolymer is a water solution containing urea-formaldehyde pre-condensate and, optionally, an additional amount of urea.

19. Foamed material according to any one of p-18, where the solution of the foaming agent and the solution of the prepolymer is served in the injector at an equal flow rate in units of volume per unit time.

20. Foamed material according to any one of PP-19, where the solution of the foaming agent and the solution of the prepolymer is served in the injector under pressure of 11.5 bar and at a flow rate of 10 l/min and the air supplied to the injector under pressure of 5.5 bar.

21. Foamed material according to any one of the preceding paragraphs, where the foamed material has a three-dimensional structure, as shown in figure 1, figure 4 or figure 5.

22. Foamed material according to any one of the preceding paragraphs in the form of a powder having a particle size of from 0.1 to 2 mm.

23. A method of obtaining a foamed material for filtering tobacco smoke, including the mixing of the air and solution of foaming agent under pressure into the mixing zone of the injector and the mixing zone filled with inert mixing elements having dimensions in the range of 2 to 15 mm, so that the formed uncured foam flow under pressure neutered is authorized foam from the mixing zone and solution of the prepolymer in the reaction zone injector with the formation of capable of curing foam, discharge of foam from the injector and drying it in the air with the formation of the cured foam material.

24. The method according to item 23, where many inert mixing elements is a lot of glass balls having a diameter ranging from 4 to 10 mm

25. The method according to paragraph 24, where the diameter of the glass beads is equal to 7 mm

26. The method according to any of PP-25, where a solution of the foaming agent is an aqueous solution containing phosphoric acid and resorcinol, and the solution of the prepolymer is a water solution containing urea-formaldehyde pre-condensate and, optionally, an additional amount of urea.

27. The method according to any of p-26, where the solution of the foaming agent and the solution of the prepolymer is served in the injector at an equal flow rate in units of volume per unit time.

28. The method according to any of PP-27, where the solution of the foaming agent and the solution of the prepolymer is served in the injector under pressure of 11.5 bar and at a flow rate of 10 l/min and the air supplied to the injector under pressure of 5.5 bar.

29. Filter for air purification, where the filter includes filter material and the filter material includes a foam material according to one of claims 1 to 21 or article 22.

30. Filter by clause 29, where the filter material also contains cellulose acetate.

31. Cigarette, includes mouthpiece and the tobacco rod, and a mouthpiece filled Phi is trusim material on one of PP-30.

32. The use of foamed material according to any one of claims 1 to 21 or article 22 for the production of filters for air purification.

33. Use p, where the cigarette filters are filters.