JPS6054032B2 - Method and device for manufacturing cigarette filter with hollow part - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a cigarette filter made of a breathable porous fibrous material and having a pocket-like hollow part inside.

Conventionally, the most commonly used filter for cigarettes is made by opening thermoplastic fibers, especially acetone-soluble cellulose acetate fiber tows, forming them into a band, and then adding a plasticizer to the band. , the fibers are partially bonded to each other, then formed into a rod shape, the periphery is covered with paper, and the rod is cut to the required length. Cigarette filters with this structure can be manufactured in a wide range of sizes by selecting the thickness and number of the constituent single fibers. It has the advantage of being able to create a filter with a high pass rate. In such a filter, the cigarette smoke particles 8 move in the space between the fibers in the filter and are removed by coming into contact with the fibers, so unless the gaps between the fibers are made small, a high penetration rate will result. can't get things. This naturally results in increased suction resistance during smoking. If the suction resistance of the filter becomes extremely large, the smoker will be forced to put in a lot of effort when smoking, so there is a limit to the ability of this type of filter to obtain a high pass rate. Currently, in Japan, to display suction resistance, we compare the negative pressure required to suction 17.5 m1 of air per second expressed in terms of the height of the water column (7 m).

8- is considered to be the limit for the suction resistance of filters in practical use, and most filters are usually 6' or less. The penetration rate is expressed as a percentage (%) of the proportion of smoke components captured in the filter relative to the total amount of smoke components smoked under standard conditions (inhaling 34 ml twice per minute). .

Most of the smoke components collected by ordinary filters are particle components (πM), and the filtration rate regarding this particle component is called the TPM filtration rate. The passing rate of only the alkaloid content in liver M is called the alkaloid (or nicotine) passing rate.
The filtration rate of TPM after water and alkaloids have been removed is called the tar filtration rate. Currently, in a filter using 4-denier cellulose acetate fiber tow, which is widely used in Japan, when the airflow resistance is 40 to 5, the TPM penetration rate is 40 to 5.
It is known that the tar penetration rate is approximately 10% lower than this, and the nicotine penetration rate is further 7 to 10% lower.
The inventors determined the denier ratio of the filter when the fiber filling amount was kept almost the same and the thickness of the filling fiber was smaller than 4 denier. The results were as shown in Table 1. As can be seen from this result, the thickness of the fibers can be made smaller in order to improve the overloading efficiency. However, when the fibers are made thinner, the rigidity decreases, and the rigidity of the rod decreases under the same filling condition, making it extremely difficult to attach the filter tip to a cigarette. When more fibers are filled in order to increase rigidity, the airflow resistance of the filter increases, which becomes a practical problem. In order to prevent this, some types of cigarettes either have small holes in the wrapping paper in the filter part or use wrapping paper with a high degree of porosity.
Some filters reduce suction resistance by allowing air to flow in from the sides of the filter during smoking. Also, in addition to this, is the filter part processed and molded? High-density, high-surface-area filters with a large surface area, such as JP-A-47-779
There are those seen in Wani and Japanese Patent Publication No. 50-31098.
Many high-density, high-surface-area filters are made by molding cellulose acetate, which is mainly used in today's cigarette filters, into a special shape. What is the purpose of this? The increased overarea reduces the rate at which smoke particles pass through the filter, causing them to become trapped in the denser, shorter passage filter media.

An example of a filter molded in this way is
0-31098, in which a recess is provided on the end face of the filter chip and a circular hole-shaped recess is provided on the other end face, and JP-A No. 47
-77 with grooves on the side of the filter, or the Reynolds (R.J.
Vantage longs (V
There are filters, such as LOngs, which have a conical recess on the end surface on the suction side and four grooves on the side surface, each of which serves the purpose of a molded filter. The inventors of the present invention are currently researching a method and apparatus for manufacturing a filter in which a void is created inside the filter and filled with an adsorbent material such as activated carbon, but the void inside the filter is not filled with anything. It was found that the filtration rate of the filter is superior to that of a filter that is homogeneous throughout and has no voids. This is not a new discovery and can be easily inferred from the various molded filters mentioned above. However, the method and device for creating a void inside a filter developed by the inventors is based on an original concept, and using this method, molded filters can be manufactured continuously and efficiently. The method for manufacturing a molded cigarette filter (having a hollow portion) according to the present invention includes the steps of (1) continuously supplying a filament bundle of thermoplastic fibers and performing a plasticization treatment to bundle them;
) Compression molding of the bundled filament bundle so that it has a substantially elliptical cross-section; and (3) pressing the filament bundle having a substantially elliptical cross-section from either side toward the center in the minor axis direction. (4) forming a cross-sectional shape in which two spindle shapes are lined up in parallel and symmetrically;
Forming pocket holes at regular intervals in the longitudinal direction of the side surface of the continuously pressed filament bundle, (5) cooling with compressed air, and (6) converging and surrounding the converged filament bundle with paper. It is characterized by comprising a winding process.

In addition, in the manufacturing apparatus for a molded cigarette filter (having a hollow portion) of the present invention, in order of the feeding direction of the bundle of continuous fibers subjected to plasticization treatment, (1) the gap between the rolls when combined is approximately equal to An apparatus for compression-molding a filament bundle into a substantially elliptical cross-section, which includes a pair of rolls that have a circular outer peripheral shape, rotate in synchronization with the moving speed of the filament bundle, and are heated to a constant temperature. 2) A gap is formed between the rolls by combining a roll having protrusions for forming pocket holes at regular intervals on the outer periphery and a roll having two parallel grooves with a semicircular cross section in the circumferential direction on the outer periphery. , a filament bundle containing a pair of rolls that rotates in synchronization with the moving speed of the filament bundle and is heated to a constant temperature, and forms the filament bundle into a cross-sectional shape in which two spindle shapes are arranged in parallel and symmetrically. A device that simultaneously forms pocket holes in the filament bundle; (3) a device that converges two parallel filament bundles with a spindle-shaped cross section and cools them with compressed air; (4) convergence and winding that wraps paper around the filament bundle. It is equipped with a device.

Hereinafter, the present invention will be described in detail based on the attached drawings.

FIG. 1 is a side view of the entire manufacturing apparatus for a molded cigarette filter (having a hollow portion) according to the present invention, in which a pair of first stage molding rolls 2 and 3, a pair of Second forming rolls 4 and 5 and a filter material supply roll 6 are attached. Reference numeral 7 is a covering material for the filter rod, such as wrapping paper, 8 and 9 are parts of a covering device, and 10 is a device for cutting the filter rod at regular intervals.

12 is a tow of cellulose acetate fiber (hereinafter referred to as a filament bundle) which is a filter material.

11 is a known plasticizer addition device for plasticizing the filament bundle.

Figure 2 is an enlarged view of the main parts of Figure 1, and Figure 3 is an enlarged view of the main parts of Figure 1.
Partial sectional view of the first stage roll along the line ■-■ in the figure, No. 4
FIG. 5 is a partial sectional view of the second stage roll.

The first stage rolls 2 and 3 are for forming the filament bundle 12 into a substantially elliptical cross section. It is constructed by combining a circular roll 3 having a recessed groove 3a in the circumferential direction. These first stage rolls 2 and 3 are
When assembled, a gap between the rolls having a substantially oval cross section as shown in FIG. 3 is formed. The second stage roll is constructed by combining a roll 4 and a roll 5, as shown in FIGS. 4 and 5.

The roll 4 has a protrusion 4b extending in the circumferential direction at the center of its outer peripheral surface (FIG. 4), and pocket hole forming protrusions 4a (FIG. 5) at regular intervals on the same outer peripheral surface.
When these two-stage rolls 4 and 5 are combined, as shown in FIG. 4, a gap is formed between the rolls having a cross-sectional shape in which two spindle shapes are arranged in parallel and symmetrically.
4 is a cutaway view of the roll 4 taken at a position where the pocket hole forming protrusion 4a is not present, and FIG. 5 is a cutaway view of the roll 4 taken at a position where the protrusion 4a is present. The first stage rolls 2, 3 and the second stage rolls 1, 5 are heated to a constant temperature by a known method and rotate at a circumferential speed that is synchronized with the moving speed of the filament bundle.

The temperature at which these rolls are heated varies depending on the winding speed, type, density, type of plasticizer, etc. of the filament bundle.
, C to 230, C. For example, when the winding speed is 80 m/min, the single yarn fineness is 3.3 denier, and the filament bundle fineness is 40,000 denier, 1
It is desirable to set the temperature to 50°C. Next, the operation of the present invention will be explained.

In FIGS. 1 and 2, a filament bundle 12 is opened by a known opening device, a plasticizer is added by a plasticizer addition device 11, and then a trumpet-shaped trumpet guide 13 for convergence is passed through a supply roll 6. The material is fed into a flat plate shape with a width of about 30 cm to a cylindrical shape with a diameter of about 2C1n, and then supplied to the first stage rolls 2 and 3. When the filament bundle 12 fed into the gap between the first rolls 2 and 3 is formed into a substantially oval cross section, the fibers are fused together at the contact surface by the heat of the rolls 2 and 3, but the contact time is Since the fibers are short, the fibers within the forming part are not completely fused, and after passing through the narrowest part of the roll gap, the repulsive force of the internal fibers tends to spread the fused fiber layer on the outer periphery. Therefore, when the filament bundle is passed through the cooling device 14 and cooled at the point where it exits the rolls 2 and 3, the fused fiber layer is fixed and the filament bundle maintains a substantially oval cross-sectional shape. Next, the filament bundle is sent to the nip between the second stage rolls 4 and 5.

Here, the filament bundle having a substantially elliptical cross section is pressed from the upper surface toward the center in the short diameter direction by the protrusion 4b of the roll 4, and has a cross-sectional shape in which two spindle shapes are lined up in parallel and symmetrically. It is molded to be. At the same time, pocket holes 36 are formed at regular intervals in the longitudinal direction on the upper surface of the filament bundle by the pocket hole forming projections 4a of the roll 4. The shape of the filament bundle after being formed by the second stage rolls 4 and 5 is shown in a perspective view in FIG. The ■-■ cross section in FIG. 7 is the part formed by the second stage roll part (the part where the pocket hole 36 is not formed) corresponding to FIG. The portion formed by the corresponding second stage roll portion (the portion in which the pocket hole 36 is formed by the pocket forming protrusion 4a of the roll 4) is shown. In addition, in order to prevent wrinkles or cracks from occurring when the filament bundle 12 is formed, the gap width 17-18 between the first stage rolls 2 and 3 is
-19 (Fig. 3) and the gap width 20-21-22 (Fig. 4) of the second stage rolls 4, 5 are preferably approximately the same. It is desirable that the upper and lower gaps of the gap be adjustable. Second stage roll 4
, 5, the filament bundle 12 formed in the above case (
As in the case after forming with the first rolls 2 and 3), the shape is immediately fixed by passing through the cooling device 15. The filament bundle 12 is bent in the longitudinal direction at the central connecting portion 12a (FIG. 7) and converged into a round bar shape, and sent together with the wrapping paper 7 to a coating device where it is wrapped round with an endless tape 25 and adhesive is attached to one end of the wrapping paper 7. is applied and it becomes like a lotus.

Then, it is sent to the cutting device 10 and cut at predetermined length intervals, that is, so that the pocket hole is located approximately at the center of the inside of one filter chip. Figure 6A shows cooling device 1
A longitudinal cross-sectional view of 5, Fig. 6B is taken from ■B-■B in Fig. 6A.
FIG.

While the bundle of filaments formed by the second stage rolls 4 and 5 passes through the passage 30, the compressed air supplied from the nozzle 28 passes through the air reservoir 29 and pours into the passage 30 from the thin tube 31. The filament bundle is cooled. The cooling device 14 for cooling the filament bundle after passing through the first stage rolls 2 and 3 also has the same structure except that the cross-sectional shape of the filament passage is different. According to the present invention, when forming a pocket hole in a fiber filter material subjected to plasticization treatment, the position can be made accurate and stable, and the single yarn fineness and filament fineness of fibers (filament bundle) can be Even when using a filament with a large filament, it is possible to easily bend the filament bundle in the longitudinal direction and converge the filament bundle, which has a cross-sectional shape in which two spindle-shaped filaments are connected in parallel and symmetrically. Hole forming,
The process up to the convergence process can be carried out quickly and efficiently.

Table 3 shows the results of measuring and comparing the physical properties of the pocket-molded filter thus manufactured and the ordinary filter without pocket-molding.

As is clear from the results in this table, even though the fiber content does not change that much, the p-permeability improves by 4 to 5% without increasing the ventilation resistance.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing the entire apparatus of the present invention, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is a partial cross-sectional view of the first stage roll, and Figs. 4 and 5 are A partial cross-sectional view of the second stage roll,
FIG. 6 is a sectional view of the cooling device, and FIG. 7 is a perspective view of the filament bundle after molding. 2, 3... First stage roll, 4, 5...
Second stage roll, 4a...Protrusion for forming pocket holes, 1
2...Filament bundle, 36...Pocket hole.

Claims (1)

[Claims] 1. A method for manufacturing a cigarette filter made of a fiber material and having a pocket-like hollow portion inside, comprising: (a) continuously supplying a filament bundle of thermoplastic fibers and subjecting the filter to plasticization treatment; (b) compression molding the focused filament bundle so that the cross section is approximately elliptical; and (c) compressing the bundle of filaments having an approximately elliptical cross section from either side in the minor axis direction. A step of forming a cross-sectional shape in which two different spindle shapes are arranged in parallel and symmetrically by pressing toward the center; (e) converging the filament bundle having a cross-sectional shape in which spindle shapes are interconnected in a parallel and symmetrical manner, and wrapping paper around the converged filament bundle; A method for manufacturing a cigarette filter having a hollow portion, the method comprising: 2. A method for manufacturing a filter in which the step of compression molding a filament bundle into a substantially elliptical cross section is performed using a pair of rolls that rotate in synchronization with the moving speed of the filament bundle and are heated to a predetermined temperature. 3. Forming the filament bundle into a cross-sectional shape in which two spindle shapes are arranged in parallel and symmetrically,
The step of forming pocket holes is performed using a pair of rolls that rotate in synchronization with the moving speed of the filament bundle and are heated to a predetermined temperature, and pocket forming protrusions are provided at predetermined intervals on the outer circumference of one of the rolls. Using something that has
The method for manufacturing a cigarette filter according to claim 1, wherein the two steps described above are performed simultaneously. 4. The method for manufacturing a cigarette filter according to claim 2 or 3, wherein the heating temperature of each roll is 100°C to 230°C. 5 After compression molding the filament bundle into a substantially oval cross section,
The method for manufacturing a cigarette filter according to any one of claims 1 to 4, comprising the steps of cooling the filament bundle after forming pocket holes in the filament bundle. 6 An apparatus for manufacturing a cigarette filter having a hollow part from a filament bundle of continuous fibers subjected to plasticization treatment, in which the gaps between the rolls when assembled are omitted in cross section in order of the feeding direction of the filament bundle; The filament bundle is made into a substantially elliptical cross section, including a pair of rolls 2 and 3, which have an oval outer peripheral shape, rotate in synchronization with the moving speed of the filament bundle, and are heated to a constant temperature. A compression molding device, (b) a roll 4 having pocket hole forming protrusions 4a at regular intervals on the outer periphery, and a roll 5 having two parallel grooves with semicircular cross sections arranged in the circumferential direction on the outer periphery; A pair of rolls 4 and 5, which rotate in synchronization with the moving speed of the filament bundle and are heated to a constant temperature, form a gap between the rolls, and spindle-shaped the filament bundle into two parallel and symmetrical rolls. (c) A device for forming pocket holes 16 in a filament bundle while simultaneously forming the filament bundle into a continuous cross-sectional shape; (c) converging two parallel filament bundles having a spindle-shaped cross section; An apparatus for manufacturing a cigarette filter having a hollow part, comprising a converging and winding device for winding a cigarette.