JP2594606B2 - Filter element for smoking article - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an improvement in a filter element for smoking articles. Although the present invention will be described with reference to a preferred embodiment of a filter for cigarette paper (hereinafter referred to as "tobacco"), the field of application of the present invention is quite wide and other applications such as filters for small cigarettes. It will be apparent to those skilled in the art that application to the system is also possible. Moreover, recent innovations have extended the use of smoking devices to areas such as the delivery of medical supplies. Examples of these applications were published July 8, 1986 by Gabriel.
iel), US Patent No. 4,598,720 and March 1986.
Included in the EPC publication issued to RJ Reynolds Tobacco Company on the 19th. The filter element according to the invention is thus useful for various types of smoking articles and is described below.

BACKGROUND OF THE INVENTION Filtered tobacco is well known and is the most common form of smoking articles. It consists of a columnar cigarette and a filter at one end wrapped in thin paper. Conventional filters have been made from compacted pieces of either paper or cellulose acetate. It has long been believed that certain thermoplastic polymers have properties that suggest their use as tobacco filter materials. For example, U.S. Pat. No. 3,595,245, issued Jul. 26, 1971 to Buntin et al., Relates to melt-blowing roving of polypropylene fibers formed as tows and processed into tobacco filters. For such polypropylene fiber tobacco filters,
It is also mentioned in U.S. Pat. No. 4,460,040, issued to Knotek et al. On Oct. 8, 1985 and the references therein, column 1, lines 44-57. Despite these teachings,
Filters of thermoplastic polymer fibers, especially those made of polypropylene fibers, have met with little commercial success. Previous attempts to make thermoplastic fiber filters have common deficiencies, one of which is that the filter ends are not distinctive due to insufficient hardness, making them uncomfortable and soft. Another is that the pressure drop was higher than expected and the smoker had noticeably increased suction resistance. For this reason, there is a demand for a filter for a smoking article which utilizes the economics of a thermoplastic fiber composition, improves the above-mentioned deficiencies, and has further improved properties so as to have other advantages.

SUMMARY OF THE INVENTION The present invention provides a filter for smoking articles. The filter is made from thermoplastic fibers, which makes the hardness of the filter desirable and also improves the pressure drop and filter efficiency. Moreover, these improvements can be obtained without increasing the production costs of the thermoplastic fibers and without affecting the taste and other tobacco properties. In the present invention, the filter is made of a preformed thermoplastic fiber web, rather than as a tow or roving, which dominated the traditional thermoplastic fiber filter.
More particularly, the present invention provides a nonwoven web suitable for use in a filter, the nonwoven web comprising thermoplastic fibers or filaments formed by melt spraying and comprising these fibers. 33% or more of them are present as molten aggregates, most of the intersections of the fibers of the aggregates are welding points, and the slenderness ratio of the aggregates is 500 or less. Various properties of the filter, such as the directivity of the fibers in the longitudinal direction relative to the transverse direction,
The unit weight, porosity, fiber width distribution, pore area ratio, tear strength, flexural modulus and the like are determined by the starting material of the thermoplastic fiber web. The filter web can be processed into a filter using a conventional filter maker, the filter comprising a web of selected width instead of a conventional cellulose acetate tow. In an embodiment of the present invention, the thermoplastic polymer is polypropylene, and the web is made by a melt spraying method.

EXAMPLES The present invention will be described by way of preferred examples, but the present invention is not intended to be limited to those examples. On the contrary, the intent is to cover all alternatives, modifications, and equivalents that may be included within the scope of the present invention as set forth in the appended claims.

The test results described below to describe the invention in detail have been obtained according to the procedures described hereinafter.

Grab tensile strength is Instron
Measurements were made in substantial accordance with the method of 5100 U.S.A. Test Method Standard 191A using an Instron 1122 test instrument from the company. The tensile strength varies depending on the state of fiber alignment in the machine direction (MD) with respect to the transverse direction (CD) of the web, and also depends on the solubility between fibers and the distribution state of fibers in the width direction.
The web according to the present invention has a grab tensile strength of about 0.1 to 3.0 pounds in the transverse direction and at least about 0.
Will be in the range of one pound. The ideal range is 0.7-2.4 pounds vertically and about 0.5-2.3 pounds horizontally.
According to the present invention, the web has a ratio of the longitudinal grab tensile strength to the transverse grab tensile strength of about 1: 1 to 4: 1, ideally
Will be 1: 1 to 2: 1.

The results of the trapezoidal tear test were obtained almost according to ASTM ~ D ~ 1117-14, except that the tear load was calculated as the average of the first and highest values, not the average of the lowest and highest values. It is. Generally, a sample is cut into a trapezoidal plate having a height of 3.0 inches and upper and lower sides of 1.0 and 4.0 inches, respectively. Next, the sample is cut at a right angle to the depth of 5/8 inch from the top side and through the midpoint of the top side (this will also cut the remaining 19/8 inch portion of the sample) ). After this, the sample is inserted into a tear tester and stopped with a stop so that the sides of the trapezoid are parallel. According to the present invention, the average tear load (as defined above) of the web will be about 0.1-3.0 pounds in the transverse direction and at least 0.1 pounds in the longitudinal direction. To do this, the test result is about 0.3-1.4 pounds in the vertical direction and 0,0 in the horizontal direction.
Preferably between 3 and 1.3 pounds.

The Frazier porosity test was carried out using a Frazier air permeability tester manufactured by Frazier Precision Machine Co., Ltd. This porosity value represents the permeability of the web. The test procedure is in accordance with Federal Test Method Standard 191A, Method 5450, except that the specimen used is 8 inches square, and the five-layer sample is measured using a 20 mm air nozzle. Frazier units represent the volume of air per square foot of sample per minute in cubic feet. The Frazier porosity of the web according to the invention is generally between 100 and 1000 cubic feet per square foot-minute, ideally 150
~ 1000 cubic feet / square foot-minute (for a 5-layer sample).

The Handle-O-Meter stiffness test was performed using a 211-5 Model Handle-O-Meter manufactured by Thwing Albert Machinery. The results of this test indicate the flexural modulus of the melt-blown web, which helps determine the workability of the web into filters and the hardness of the resulting filters. Typically, a sample of a 4 inch square web is placed on a 1/4 inch wide slot and the force required to push the sample through the slot is measured in grams and length. The results of this test on a web according to the invention will not exceed 40 grams in both the machine and transverse directions.

The basis weight of a web according to the present invention, particularly suitable for filters, is generally about 0.5 to 1.0 ounces per square yard.

Pore area ratio is a measure of web opening and is measured by Quantim manufactured by Cambridge Machinery.
et) type 970 image analyzer. This value is important in determining the filtration characteristics of a filter made with the web according to the invention. Generally, the web area ratio of the web according to the present invention is about 10-60%, with an ideal range of about 14-
It is in the range of 52%.

The cross-sectional dimensions of the fibers and fiber agglomerates
It was measured using an SEM photograph. The web was made into a filter shape to take a single photograph of many fiber cross sections and then cut with a cutter. The cutting was performed with the filter immersed in liquid nitrogen so as not to stain the cut surface of the fiber.

Agglomerates in the present invention are bundles of molten or partially melted fibers or filaments, and webs useful in the present invention are rich in agglomerates, i.e., more than half of the fibers or filaments are agglomerated. Includes in state. SEM pictures were also taken from a direction perpendicular to the web to determine the length of the fiber agglomerates (ie, the average distance between the points where these agglomerates are fused together on the web plane). Optical microscopy was used to determine this length,
The procedure involves first measuring the distance between the intersections, then slicing the agglomerate of interest with an incision needle and examining the intersection for melting. Generally, the web according to the invention has a weld point at the majority of the intersections of the fiber agglomerates. What was not understood with the conventional melt-blown web.

Additional tests were also performed on filters manufactured by conventionally used manufacturing machines. This test is for filter weight, hardness and dents, pressure drop and filter efficiency. Hereinafter, each test is described.

The filter weight is the mass of the web incorporated in each filter, and the unit is expressed in mg of the weight of the web per cm of the filter. Generally, but not pertinent to the present invention, the ideal range of filter weight is 55-95 mg / cm filter.

The hardness of the filter was obtained using a 19 mm diameter platen. The filter was placed in contact with the platen under the platen, and the first measurement under no pressure was obtained. In this state, about 27 g of force was applied to the filter. Next, add 100g to the platen
Was applied. After a lapse of 10 seconds in this state, a second measurement value was obtained. The unit of hardness is expressed in%, and the value is 2
The value obtained by multiplying the value obtained by subtracting the first measured value from the first measured value by 100 was obtained. Generally, the hardness of the filter ranges from about 94 to
About 99%, with an ideal range of about 96 to about 98%. The test was also performed on a filter (i.e., a conventional filter tobacco) attached to tobacco material (bar-only tobacco without a filter). These cigarettes were lit, and suction was continued at a rate of 185 cc per minute to measure the dent of the filter shown in FIG.

Generally, the pressure drop of the filter is 1050 per minute.
The pressure drop when cubic cm of air passes through the filter is expressed in cm of water. This pressure drop value is reduced by the actual length of the filter and converted to a value per unit length of the filter.
In the present invention, the pressure drop is generally from about 0.1 to 6.0 water cm / filter, with an ideal value being from about 0.5 to about 4.5 water cm / filter cm.

The total amount of particulate matter resulting from smoking tobacco with a filter (21 mm long) was determined by the method of the FTC (US Federal Trade Commission). This method starts with a tobacco material (length 70 mm, diameter 8.
0 mm) and a filter was inserted into a smoking machine (model RM4 / CS) manufactured by Heinr Borgwaldt. In the smoking test, 35 cc of suction was performed once a minute for 2 seconds. The total amount of particulate matter was determined by weighing Cambridge filter pads before and after the smoking test.

The filter efficiency was determined by measuring the total amount of particulate matter as described above. The filter efficiency is expressed as a percentage by multiplying the value of the test result of the filtered tobacco by the value of the test result of the filtered tobacco multiplied by 100.

The water release of the total particulate matter was also determined by extraction with isopropyl alcohol (internal literature methanol) from the Cambridge filter pad by gas chromatography. Nicotine excretion was also determined by extraction with methanolic hydrochloric acid from a Cambridge filter pad by ultraviolet absorption spectroscopy.

The results of the emissions (total particulate matter, nicotine, moisture) are shown in Table 6. The unit is the amount per cigarette and the amount per suction. As is evident from Table 6, the performance of the filter made with the web according to the invention is similar to a conventional cellulose acetate filter, with a nicotine output of about 5% and a water output with respect to the total particulate matter. 15-20%.

While most thermoplastic polymers can be used in the present invention,
Preferred are those based on polyolefins such as isotactic polypropylene and polyesters such as poly (butylene terephthalate). Due to the nature of the melt-blown thermoforming process, when forming a melt-blown web into the shape of a filter element, additives (eg, calcium carbonate) are melted or sprayed onto the molten polymer surface.
Can be easily incorporated into the polymer. The melt-blown webs also need to be post-treated with their dry or liquid auxiliaries after they have been formed, so that they have organoleptic and / or medicinal properties.

A method for making a web useful for the present invention is the melt spraying method as described in U.S. Patent No. 3,384,241. This method is also used in the present invention.

FIG. 1 shows a conventional melt spraying method. Pellets 4 are supplied from a hopper 3 to an extruder 1 driven by a motor 2. The extruder 1 is heated to a viscosity necessary to feed the polymer to the die 5. As the polymer is extruded from the die 5, it is exposed to the hot air discharged from the conduit 6 from both sides. If necessary, the die 5 is heated electrically or by other means using the conduit 7. The fibers 8 are sent to the collection surface 9 by an air flow to form a mat 10. The collecting surface 9 comprises a drum 11 rotating about an axis 12 as shown or a belt, screen or other device as will be apparent to those skilled in the art.

FIG. 2 shows means for processing the web into a filter.
In general, this means is little different from the usual means using cellulose acetate tow.

As schematically shown in FIG. 2, the rolls 13 of the thermoplastic fiber web 10 are unwound and fed into a preforming device 14, where the flat web 10 is adapted for passage to a filter making machine.
Are collected or folded into a cylinder. A paper web 16 (called a plug wrap) is wound around the thus formed cylinder 15 and then cut into a predetermined length 17 by a cutter 18. The cut thing is conveyed to an attached device by an endless belt (not shown). More specifically, before being transported to the accessory, one end of the plug wrap is continuously coated with an adhesive bead by an applicator, and as these webs and wraps pass through the accessory, the web becomes circular in cross section. It is compression molded into a shaped bar and at the same time a plug wrap 16 is wound therearound. When the adhesive bead comes into contact with the overlapping portion of the rod-shaped material around which the plug wrap 16 is wound, the stick-shaped material is sealed by the sheet-shaped rod. After that, it is cut into pieces 17 of a predetermined length by a cutter 18.

FIG. 13 is a partial view showing a cigarette as the smoking article 50. The illustrated cigarette comprises tobacco material wrapped in tobacco wrapper 60 and coupled to a filter 54, which comprises a web 56 wrapped by wrapper 62 and a plug wrap 58.

Although it is not essential to make the desired filter,
A web made according to the present invention may be pre-treated before processing into a filter. Two such pretreatments are shown in FIG. 2, one being a set of grooved rollers 19 for crimping and the other being a liquid treatment machine 20 for surface treatment.

With reference to FIGS. 3 to 6, FIGS. 3 and 4 show filters made from two webs according to the invention, FIG. 5 shows a filter made from a conventional melt-blown web, and FIG. 6 shows a filter made from a spun web. 5 is an SEM photograph of a cross-sectional view of FIG. 7 to 10
The drawings are plan views of the web shown in FIGS. 3 to 6, respectively. The magnification is the same for all photographs and can be determined by measuring the reference line at the lower right corner of each photograph. The reference line corresponds to 100 microns. Examination of these photographs reveals that the spread of large fiber agglomerates formed by the partial dissolution of the fibers during web forming is particularly pronounced for the webs shown in FIGS. At 0.8 oz and 0.6 oz). FIG. 12 is a cross-sectional view of the web according to the present invention, showing the web 30, the fiber aggregate 32, and the bonding intersection 34.

The distribution state of the fiber aggregates is obtained by counting the number of cross sections of the fiber aggregates in the same photographs as in FIGS. 3 to 6, and the results for FIGS. 3 to 6 are shown in Table 1. The distribution of fiber agglomerates in the webs of FIGS. 3 and 4 clearly shows that these webs are different from conventional meltblown or spun webs. In addition, Sample 0 was prepared by the method shown in Figure 1 except that the number of fiber agglomerates was reduced (per square yat).
0.6 oz).

It can be seen that these dissolved fiber clumps increase the flexural modulus of these webs and increase the stiffness of filters made with these webs. Without these fiber clumps, filters made of polyolefin tow or web would not have adequate hardness. Furthermore, the presence of these fiber agglomerates makes webs made using the present invention distinctly different from meltblown webs. In fact, it is said that there is no fiber agglomeration in a currently sold melt-blown web from the viewpoint of function and aesthetics.

Using a conventional melt spraying device as shown in FIG.
When forming a web as shown in the Figures and FIG. 4, operating parameters are adjusted to produce the desired fiber agglomerates.
Usually such fiber agglomerates are considered unnecessary,
The operating conditions are adjusted so that fiber aggregates are not formed as much as possible. However, in this regard of the present invention, parameters such as temperature as well as formation distance vary from polymer to polymer. For example, reducing airflow and formation distance tends to increase fiber aggregation.

Without being limited to any particular theory in the present invention,
It is believed that the desired hardness and pressure drop properties of the filter are due to the fact that the fiber agglomerates function like columns and strongly prevent buckling when forming the filter from the meltblown web. This column and the problem of its mechanical function are discussed in JP Vidosic, "Standards Handbook for Mechanical Engineers" (New York McGraw-Hill, 1958), 8th edition, "Material Mechanics", Chapters 5-40 to 5-5. At page -42, he states:

"Pillars: Members that are directly subjected to pressure can be classified into three types. If the column is extremely short (elongation ratio of 30 or less), the member will not bend. If the column is elongated and the bending is usually in the range of Euler ( It is a long pillar according to Euler's theory, and the middle one, which is actually common, is called a short pillar.

Long columns and thinner and shorter columns will buckle when the load reaches a critical point. This is an instability problem. That is,
The column will continue to yield and flex even if the load does not increase above the critical point. The slenderness ratio is a value obtained by reducing the buckling length by the minimum sectional turning radius. Long columns follow the Euler column buckling stress formula.

P _cr = nπ ² EI / L ² = nπ ² EA / (L / R) ^{2 In the} above equation, P _cr = buckling load n = coefficient determined by the terminal condition of the column (n =
4) E = Modulus of longitudinal elasticity I = Second moment of area A = Cross-sectional area of column L = Length of column R = Minimum section turning radius. R is a value obtained by reducing the diameter by 4 in a circular cross section, and a value obtained by reducing the length of a short side by a square root of 12 in a rectangular cross section. (Here, the value obtained by reducing the minimum sectional diameter by 4 is R.) "The dimensionless ratio L / R in the above equation is the" elongation ratio ". In order for the columns to collapse only by buckling, this ratio needs to be at least 120, preferably at least 150, and most of the columns considered here are in this range. It should also be noted in Euler's equation that the critical buckling load is inversely proportional to the square of the slenderness ratio, and is therefore greatly affected by small changes in column dimensions.

In the fibrous structure, the unit of the modulus E is usually gram / denier. Thus, the cross-sectional area A in Euler's equation is also expressed in units of denier, and thus the unit of the product EA is gram. Taking the polypropylene used in the present invention as an example, E ≒ 10 g / denier. (This low value of E contrasts with the value of E of cellulose acetate used in conventional tobacco filters, E ≒ 45 grams / denier. The difference in this value of E has little success as a filter for tobacco. Table 2 shows the specifications of the web shown in Figs. 3 and 4 and Table 1. From this, Euler's equation is applied to the fiber components and fiber agglomerates. can do. Conventional melt-blown web and web according to the present invention (shown in FIGS. 3 and 4)
The significant difference in denier and slenderness ratio is clear when compared to As shown in the right column of Table 1, the difference in slenderness ratio causes an increase in buckling load.

At least one third of the web according to the present invention is a fiber agglomerate, and the slenderness ratio is 1000 or less for a single fiber and 500 or less for a fiber agglomerate.

Such an increase in buckling load caused the web of FIGS. 3 and 4 to be processed into a filter of appropriate hardness, and also caused a large pressure drop inherent in a filter made of a conventional melt-blown web. This indicates that processing can be performed without dents. Similarly, the fact that the spun web has an infinite slenderness ratio (and thus has no buckling load) means that when it is processed into a filter, it has the same problems as polypropylene, i.e., with adequate filter hardness, a large pressure drop. This indicates that there is a problem. Table 3 shows all of these factors.

In the present invention, the fiber aggregate has a length of 1 to 2 mm, a denier of 2 or more, and an equivalent diameter of 20 to 100 μm (for polypropylene, 2.5 to 65 μm).
Denier) is preferred. Furthermore, the percentage of fiber agglomerates
Preferably, it exceeds 40%. To make a filter with a large pressure drop, the denier of the fiber agglomerate is preferably low. To make a filter with a small pressure drop, the diameter of the fiber agglomerate may be increased.

Sample 0 reduced the number of fiber agglomerates and reduced the pressure drop by about 2.
With 9 cm / water cm, it shows almost the maximum pressure drop suitable for the filter.

Examples Experimental Examples 1-4: The webs of Experimental Examples 1-4 were produced using equipment similar to the apparatus shown in FIG. 1 and had a unit weight of 0.6 ounces and 0.8 ounces per square yard, respectively. is there. The thermoplastic polymer used in these examples is Exxon 3214 polypropylene. Table 4 shows the physical quantities of these webs.
The performance and emissions of filters made with these webs are shown in Tables 5 and 6, respectively. Table 5 also includes data for a cellulose acetate filter (referred to as Control 1) taken from Marlboro tobacco. Table 6 shows Control 1 and Control 2.
(Representing Marlborough's filtered tobacco and unfiltered tobacco, respectively).

Experimental Examples 5 to 6: Experimental examples 5 and 6 were manufactured using the apparatus shown in FIG. Experimental Example 5 is 10% (weight%) of calcium carbonate manufactured by Genstar, and Himont PC
It has 90% (weight%) of -973 polypropylene. Calcium carbonate is pre-mixed with polypropylene,
After extruding and pelletizing, the mixture is melt sprayed to form the web according to the present invention. Due to the structural differences between the fibers, filters made by mixing calcium carbonate tend to alleviate the filtering properties as found in filter elements made from fiber-exposed webs.

Experimental Example 6 was performed by General Electric (General Electr
ic) Consists of Valox 315 poly from the company. The physical quantities and filter characteristics of the webs of Experimental Examples 5 and 6 are shown in Tables 4 and 5, respectively.

From the data in Tables 4, 5 and 6, the filters made with the web according to the invention have excellent filter properties, especially with regard to pressure drop and discharge, which are the properties of conventional cellulose acetate filters. It can be seen that they also have Further, it can be seen that the pressure drop varies over a wide range, and that the hardness of the cellulose acetate filter can be maintained at a level higher than the hardness of the filter. Therefore,
The thermoplastic fiber filter provided by the present invention has the desired filtration characteristics, and the dent reduction and the hardness are improved as compared with the conventional one so as to be understood by hand.

FIG. 11 shows how the filter hardness changes as the length of the tobacco material decreases with smoking. This figure shows the change of the filter made of the polypropylene web according to the present invention and the change of the conventional cellulose acetate filter. As can be seen, the filter made of the web according to the present invention does not exhibit the extreme dents exhibited by conventional cellulose acetate filters.

The dent resistance of the filter made of the web according to the invention has a great influence on the smoking of filtered tobacco. First and foremost, this filter eliminates the weakness of the filter which many smokers have noted as undesirable properties.
Second, and more importantly, the extreme dents of the filter during smoking can be converted into a groove along the periphery of the filter element. Because of this groove, the smoke can bypass the filter part, so that a decrease in the filtration efficiency of the filter can be avoided.

Thus, it is apparent that the present invention can provide an improved filter material for a smoking article that fully satisfies the objects and advantages set forth above. In addition, in light of these descriptions, in connection with what has been described with reference to the embodiments, many alternatives, modifications, and applications will be apparent to those skilled in the art. Accordingly, applicants intend that the scope of the claimed invention encompasses all selections, modifications and adaptations.

[Brief description of the drawings]

Fig. 1 is a perspective view showing one method of forming a web according to the present invention, Fig. 2 is a schematic view showing a method of processing a web into a filter, and Figs. Electron micrograph instead of a drawing showing the shape, FIG. 11 is a graph of the change in the dent of the filter during smoking, FIG. 12 is a partial perspective view of the web according to the present invention, and FIG. 13 uses the present invention. It is a partial perspective view of a smoking article. (Description of Signs) 1 ... Extruder, 2 ... Motor 3 ... Hopper, 4 ... Pellet 5 ... Die, 6 ... Conduit 7 ... Conduit, 8 ... Fiber 9 ... Collecting surface, 10 ... … Mat 11… Drum, 12… Shaft 13… Roll, 14… Preforming device 15… Cylinder, 16… Plug wrap 17… Predetermined length, 18… Cutter 19… Groove Roller, 20 ... Liquid treatment machine 30 ... Web, 32 ... Fiber agglomerate 34 ... Bonding point, 50 ... Smoking goods 54 ... Filter, 56 ... Web 58 ... Plug wrap, 60 ... Tobacco Wrapping paper 62 ... wrapping paper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Leon e Chambers Jr., Georgia, USA 30076 Roswell Mill Creek Places 245 (72) Inventor Lloyd G. Kasbo, USA 30092 Norcross Valley Mist to Wraith 5404 (72) Inventor William F. Cartwright United States Georgia 30076 Roswell North Pond Trail 480 (72) Inventor Robert G. Georgia United States 30114 Canton North Stringer Road Route 12 Box 453 (72) Inventor Edward P. Balwinkel United States Georgia 30076 Roswell Cedar Nor Drive 2975 (56) Document JP Akira 47-28281 (JP, A) JP Akira 52-132170 (JP, A)

Claims (16)

(57) [Claims] The present invention comprises thermoplastic fibers or filaments formed by melt-blowing, of which at least 33% are present as molten agglomerates and the majority of the intersections of the agglomerate fibers are at the welding point. Wherein the elongated ratio of the agglomerates is 500 or less. 2. The nonwoven web according to claim 1, wherein the thermoplastic is selected from the group consisting of polyolefins and polyesters. 3. The nonwoven web of claim 2 wherein the thermoplastic is polypropylene and the agglomerate denier ranges from about 2.5 to 65. 4. The nonwoven web according to claim 2, comprising one or more additives. 5. The method according to claim 1, wherein the unit weight is about 0.5 to about 0.5 square yards.
1.0 ounce, the ratio of the longitudinal grab tensile strength to the transverse grab tensile strength is about 1: 1 to 4: 1, and the handle ohm meter stiffness is less than 40 grams in both longitudinal and transverse directions. A nonwoven web according to item (1), (2), (3) or (4). 6. The five-layer porosity of about 150 to 1
The nonwoven web according to claim 5, wherein the fiber has an elongation ratio of 1,000 or less. 7. A smoking article filter comprising a non-woven web of thermoplastic, melt-blown fibers or filaments having a cylindrical shape suitable for smoking articles, said fibers or filaments comprising at least 40% of said fibers. Is present as an agglomerate, and most of the intersections of the fibers in the agglomerate are weld points; the web has a unit weight of about 0.5 to 1.0 ounces per square yard and a longitudinal grab tensile strength. A filter for smoking articles, characterized in that the ratio of the grab tensile strength in the transverse direction to the tensile strength in the transverse direction is about 1: 1 to 4: 1, and the slenderness ratio of most of the agglomerates is 500 or less. 8. The method according to claim 1, wherein the hardness is about 94 to 99% and the pressure drop is
The filter according to claim 7, wherein the filter has a water column of about 0.1 to 6.0 cm per cm. 9. The filter according to claim 7, wherein the thermoplastic material is selected from the group consisting of polyolefins and polyesters. 10. The filter according to claim 9, wherein the thermoplastic substance is polypropylene. 11. The filter according to claim 9, wherein the web contains one or more additives. 12. A smoking article comprising a cigarette wrapped with wrapper and a filter, said filter having a cylindrical shape suitable for smoking articles, and comprising a thermoplastic meltblown fiber or filament. Consisting of a non-woven web,
The fibers or filaments are present as agglomerates in a fraction of 33% or more, and the web has a unit weight of about 0.5 to 1.0 ounces per square yard and a ratio of longitudinal to transverse grab tensile strength. A smoking article characterized by having an elongation ratio of about 1: 1 to 4: 1, most agglomerates of about 120 to about 500. 13. A smoking article according to claim 12, having a filter having a hardness of about 94 to 99% and a pressure drop of about 0.1 to 6.0 water cm / cm of filter. 14. The smoking article according to claim 12, wherein the thermoplastic material is selected from the group consisting of polyolefins and esters. 15. The smoking article of claim 14, wherein the thermoplastic is polypropylene and the denier of the agglomerates ranges from about 2.5 to 65. 16. A smoking article according to claim 14, wherein the web contains one or more additives.