JPH02242663A - Preparation of cigarette filter - Google Patents

Abstract

PURPOSE:To prepare a cigarette filter having a suitable air flow resistance, hardness and filterability only by the adjustment of an operation condition by employing polyolefin fibers as a raw material and using a known cigarette filter-winding device. CONSTITUTION:Many polyolefinic fibers such as polyethylene fibers or ethylene- propylene copolymer fibers each having a fineness of 1-7 denier are collected and twisted to give a tow having twists in a density of 30 turns per inch of the fibers. The tow is opened with a cigarette filter plug-winding device under conditions comprising a pre-tension roll pressure of 1.5-2.5kg/cm<2>, a blooming roll pressure of 2.5-4.0kg/cm<2> and a peripheral speed ration of 0.5-0.6 between the pre-tension roll and the blooming roll, followed by winding up the opened fibers in a rod-like state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a cigarette filter using polyolefin fibers.

[Conventional technology]

The most commonly used conventional cigarette filter material is acetate m-fiber, and other materials include paper, bulbs, and polyolefin fibers.

Among these, polyolefin fibers have been attracting attention as a material for cigarette filters because they are relatively inexpensive, but they have not been considered to be a fiber that can replace acetate fibers.

-i. When manufacturing cigarette filters using these fibers, methods such as uniformly dispersing short fibers and winding them into a rod shape and winding tow-like fibers into a rod shape can be considered. In the above method as well, it is necessary to bond the fibers together while maintaining an appropriate gap between the fibers. However, in the case of polyolefin fibers, there are no existing fiber binders that can be used in cigarette filters, so the thermoplasticity of polyolefin fibers is used to bind the mutually contacting portions of the fibers with hot air. A method of manufacturing cigarette filters is to melt the fibers using high-temperature steam and bond the fibers to form a rod shape, and then cover the rod with wrapping paper.

However, a lot of thermal energy is required to raise the surface temperature of the fibers to the melting temperature, and the equipment for the heating process is also large. Further, when the rod manufactured by such a heating method is cut with a cutting analyzer, if the fiber temperature does not fall below the softening temperature, the cut surface of the obtained cigarette filter will be defective.

In order to avoid this, it is necessary to cool the rod for a sufficient amount of time or to add a cooling device for sudden and rapid cooling. When attempting to manufacture cigarette filters at high speed using a cigarette filter plug winding machine, these factors increase manufacturing costs.

[Problems to be Solved by the Invention] The present invention uses polyolefin fibers, which have suitable ranges of ventilation resistance, hardness, and filtration rate, and which are produced using a conventionally known cigarette filter plug winding machine. An object of the present invention is to obtain a cigarette filter having a circular cross section suitable for being bonded to a column portion of a cigarette.

[Means to solve the problem]

The object of the present invention is to bundle a large number of polyolefin fibers with a fineness of 1 to 7 deniers, crimp them to form a tow so that each inch of fiber length has 30 or more ridges, and wrap the tow into a cigarette filter plug. Buritension roll pressure 1.5-2.5kg/ca depending on the upper machine! , blooming roll pressure 2.5-4.0 kg/cffl, circumferential speed ratio of blooming roll and blooming roll 0.5
This is achieved by a method for manufacturing a cigarette filter in which the fibers are opened under conditions of ~0.6 and then rolled up into a rod shape.

The polyolefin fibers used in the present invention are fibers obtained from polyolefin resins such as polyethylene, polypropylene, ethylene propylene copolymer, ethylene vinyl ester copolymer, and ethylene acrylic copolymer, and fibers made by compositing these polyolefin resins. It's okay.

Such polyolefin fibers have a fineness of 1 to 7.
It is best to have a denier within the denier range.If the denier is less than 1 denier, the filtration rate as a filter will be improved, but it will become too hard and the ventilation resistance will tend to increase. Although the resistance becomes smaller, the filtration rate becomes poorer and the quality variation becomes larger.

Further, the degree of crimp of the polyolefin fiber used in the present invention needs to be 30 or more crimps per inch of fiber length. If the degree of crimp is smaller than this, it is difficult to open the tow of polyolefin fibers, which not only reduces the efficiency of the filter plug winding machine but also reduces the filtration rate of the manufactured filter plug.

Such polyolefin fibers are obtained in the form of a tow in which a large number of polyolefin fibers are bundled, and are supplied to a cigarette filter plug winding machine in the form of a tow. The polyolefin crimped fibers supplied to the filter plug winding machine are manufactured under the following conditions: britension roll (P roll) pressure in the equipment used is 5 to 2.5 kg/c++l, blooming roll (B roll) pressure is 2.5 to 4. 0 kg/c+i
The fibers can be opened sufficiently within the range of the circumferential speed ratio between the L and P rolls and the B rolls of 0.5 to 0.6. In order to fully open polyolefin fibers in this way, it is necessary to use P rolls and B rolls.
It has been found that increasing the processing time and distance of the polyolefin fibers between rolls and increasing the degree of stretching significantly enhances the opening effect.

In addition, in the commonly used cigarette filter plug winding machine, in order to avoid increasing the size of the equipment and extend the distance and time of the opening process, one or more cigarette filter plugs are installed between the P roll and the B roll. It is preferable to adopt operating conditions that increase the degree of opening, such as by providing several auxiliary rolls (T rolls).

[For production]

The cigarette filter obtained by the manufacturing method of the present invention is not only cheaper than conventional filters using acetate tow, but also comparable in terms of ventilation resistance, filtration rate, hardness, and roundness.

Next, examples of the present invention will be described.

[Example] Filament denier 3 denier, total denier 3
Made of 4,000 denier polypropylene tow A with 35 crimps per inch, the KD! Filter plugs were manufactured using a 2-winding machine under the operating conditions shown in Table 1.

Similarly, the filament denier was 3 denier and the total denier was 34,000 denier.

Using polypropylene tow B with 25 crimps per inch and acetate tow C with a filament denier of 3 denier, a total denier of 36,000 denier, and 33 crimps per inch, under the same operating conditions shown in Table 1. A filter plug was manufactured.

Table Test number Tow P roll pressure used (kg/cd) 1.8 1.2 1.8 1.2 P/B ratio 0.55 0.65 0.55 0.65
T-roll Yes No Yes No Regarding the filter plug with a length of 120 mm manufactured in this way, the weight (g/piece), diameter (in order), right circularity (II
II11=difference between major axis and minor axis in cross section), hardness (I
IIIl: Amount of deformation after 3.5 seconds by placing a 12 o IIIll filter plug between parallel plates and applying a load of 300 g), ventilation resistance (mm) 1. O: Air passing amount 1
Table 2 shows the evaluation results of the differential pressure required to provide 7.5 m i /sec), appearance, and flavor when smoking tobacco smoke.

Table Test Number Weight (g/piece > 0.76 0.90 1.10
0.75 diameter (am) 7.8 7.8 7.
6 7.8 Roundness (body) 0.15 0.25
0.25 0.15 Hardness (n+m) 1.1
0 1.50 1.50 1.10 Airflow resistance (mmll
zO) 320 450 500 320 appearance
General Unsuitable Unsuitable Luther cannot be obtained.

〔Effect of the invention〕

According to the method for manufacturing a cigarette filter of the present invention, the fineness is 1 to 7 deniers and the degree of crimp is 30 per inch of fiber length.
Using a tow of polyolefin fibers of more than 1,000 liters as material, the performance can be improved by simply adjusting the operating conditions using a known cigarette filter plug winding machine, without using the heat fusion method that was previously thought to be necessary. It is possible to produce a cigarette filter with good quality, which is extremely advantageous economically.

Claims (1)

[Claims] A large number of polyolefin fibers with a fineness of 1 to 7 deniers are bundled and crimped to obtain a tow so that there are 30 or more strands per inch of fiber length, and the tow is passed through a cigarette filter plug winding machine under pretension roll pressure. 1.5-2.
5kg/cm^3, blooming roll pressure 2.5~4
．． A method for manufacturing a cigarette filter, which comprises opening the fibers under conditions of 0 kg/cm^3 and a circumferential speed ratio of a pretension roll and a blooming roll of 0.5 to 0.6, and then winding the fibers into a rod shape.