JPH0711559A - Method for producing nonwoven fabric and apparatus - Google Patents

Abstract

PURPOSE:To form a uniform nonwoven fabric having excellent appearance by quenching and solidifying a spun filament group by rapidly accelerating cooling air and simultaneously depositing the filament group on a collecting face by a nozzle capable of freely controlling the interval. CONSTITUTION:In the production of a polyolefin-based spunbonded nonwoven fabric, a filament group 8 obtained by spinning a polypropylene having 15-120g/10min MFR at 230 deg.C under 2160g load from a spinneret 1 having 8holes/ cm<2> hole density is cooled in throat part 2 having 50-200 mm length and then introduced into a pressure chamber 3 in which cooling air having 5-40 deg.C temperature is introduced at a rate of 0.1-2.0m/sec. In the pressure chamber 3, the cooling air is introduced from a cooling air inlet 5 provided with dampers in stages partitioned into plurality through a rectifying filter 6 and the filament group 8 is quenched and solidified by accelerating the cooling air until a rate from about <=10m/sec to 20-100m/sec and then, deposited through a nozzle 7 consisting of a pair of plates having variable interval and 150-300mm length onto a movable collecting face 9 to form a web and the web is subjected to interlacing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric used for various purposes such as medical / sanitary materials, civil engineering materials, industrial materials, and packaging materials, and more particularly to a method and apparatus for producing spunbonded nonwoven fabric.

[0002]

2. Description of the Related Art A method for producing a spunbonded nonwoven fabric is an open type in which a spun filament is drawn through a round air gun or a slit air gun and then spread on a mesh belt by a separator or an oscillator.
JP-A-57-35053, JP-A-60-155765
As shown in the publication, there is a closed type in which a spun filament is cooled by cooling air introduced into a pressurizing chamber, then drawn out through a nozzle and sprayed on a mesh belt.

[0003]

The latter type using a pressure chamber as described above can obtain a good filament and a web excellent in uniformity by a simple process, but it is a conventional method. The method described in (1) uses a pressure chamber of 0.5 to 5 kg / c to obtain a filament with sufficient strength and small fineness.
It was necessary to increase the pressure to m ² G.

It is an object of the present invention to provide a method and an apparatus for producing a filament having a sufficient strength and a fineness with a lower pressure process air than ever before.

[0005]

Therefore, as a result of various experiments, the inventors of the present invention have found that when a polyolefin is used and a throat of 50 to 200 mm is provided between the spinneret and the pressure chamber, the pressure chamber is Even if the pressure is less than 0.05 kg / cm ² G,
It has been found that a stable filament can be obtained, and further, if the nozzle length is set in the range of 150 to 300 mm, a non-woven fabric excellent in appearance and excellent in uniformity can be obtained by the low-pressure process air described above. .

The present invention has been made on the basis of these findings, and a continuous collecting filament composed of a large number of polyolefins spun from a spinneret is cooled by cooling air introduced into a pressurizing chamber, and then a moving collecting surface. In the method of manufacturing the non-woven fabric to be deposited on the above, a slow cooling process of promoting the molecular orientation of the filament before the start of crystallization in the range of 50 to 200 mm from the spinneret to the cooling chamber, and adding the filament expressing the molecular orientation It is characterized in that it comprises a process of rapid cooling and solidification by a cooling air of 0.05 kg / cm ² G or less introduced into the pressure chamber.

According to this method, the filament to be spun is stable even with a low-pressure process air of 0.05 kg / cm ² G or less, and no yarn breakage or wobbling occurs. In this method, the slow cooling process is carried out within the range of 50 to 200 mm. When the length is less than 50 mm, the filament is rapidly cooled to easily break the yarn, and when it exceeds 200 mm, the yarn shakes. This is because if the yarns start to occur and the yarn shakes violently, the spinning cannot be performed.

In the method of the present invention, in the rapid solidification process through the nozzle, cooling air of 5 to 40 ° C. introduced into the pressurizing chamber at a rate of 0.1 to 2.0 m / sec is applied at a speed of about 10 m / sec or less to 20 ° C. It can be brought about by accelerating to a speed of ~ 100 m / sec. The polyolefin used in this method is desired to have an MFR of about 15 to 120 g / 10 minutes at 230 ° C. and a load of 2,160 g.

In another preferred method, the length of the nozzle is 150 to 300 mm in the above method. As a result, a nonwoven fabric having a uniform appearance and an excellent appearance can be obtained. In the present method, the nozzle length is set to 150 to 300 mm because the filament made of polyolefin can be sufficiently stretched in this range, and the pressure in the pressurizing chamber is increased even if the length exceeds 300 mm. This is because it only has to be performed, and is unnecessary even if further stretching is performed. On the other hand, if the nozzle length is less than 150 mm, the tension on the filament is not sufficient, the stretching is insufficient, and the appearance of the resulting nonwoven fabric is deteriorated.

An apparatus for carrying out the above method is provided with a spinneret for spinning a large number of filaments made of polyolefin and an inlet for cooling air, and the spun filament is cooled by the air introduced through the inlet. A pressure chamber for solidification, and a length of 50 to 200 for connecting the spinneret and the pressure chamber.
mm throat, a nozzle having a shape that adjusts the wind speed and pressure of the cooling air to a state effective for stretching the filament, and a means for collecting and confounding the filament blown from the nozzle And

In a preferred device, the former device:
The length of the nozzle is 150 to 300 mm. In the above apparatus, the spinneret preferably has a hole density of 8 holes / cm ²
The following are used: Further, the cooling air inlet is divided into one or more stages, and preferably a damper for adjusting the air volume is provided in each.

The nozzle is composed of a pair of plates arranged to face each other with an appropriate gap, at least one of which can move forward and backward toward the other, and when the filament is passed through the nozzle at the beginning of spinning, It is desirable to make it easier and to be able to adjust the nozzle gap according to the spinning conditions. The nozzle is also preferably chamfered at the open end of the nozzle to form an R shape. This can reduce the pressure loss of the air passing through the nozzle.

As means for entanglement of filaments,
A needle punching machine, a hot embossing machine, a water jet, etc. are mentioned as an example, and one or more of these are used. FIG. 1 shows an example of an apparatus according to the present invention, in which a pressurizing chamber 3 connected to a spinneret 1 via a throat 2 is divided into upper and lower four stages, each of which is provided with a damper 4. Inlet 5 and rectifying filter 6 inside
And 7 are symmetrically arranged, and the nozzle 7 connected to the lower end is configured to be opened and closed by the operation of an air cylinder (not shown) connected to one of a pair of plates constituting the nozzle. The tip of each plate is chamfered on the inside as shown in FIG. 2 to form an R shape 7a.

In the figure, L ₁ is the throat, L ₂ is the pressure chamber, L ₃ is the discharge port, and L ₄ is the nozzle length. The present apparatus is configured as described above, and the filament group 8 spun from the spinneret 1 is thinned by the tension given by the nozzle 7 while being gradually cooled in the throat 2. Then, in the pressurizing chamber 3, the temperature, the humidity, the air volume, and the air direction are controlled from the inlet 5 to be cooled and solidified by the cooling air introduced. The cooling air is rapidly accelerated due to the reduction of the opening area of the nozzle 2, thereby giving tension to the filament and rapidly cooling and solidifying the filament. The filament group 8 blown out from the nozzle 7 is scattered on the moving and collecting surface 9 and then entangled by an entanglement means such as a needle punch machine (not shown).

[0015]

【Example】

Example 1 Using the apparatus shown in FIG. 1, L ₂ = 1,000
mm, L ₃ = 300 mm, L ₄ = 300 mm, the length of L ₁ was changed to 20, 50, 200, 300 and 500 mm, and a nonwoven fabric was produced from polypropylene as follows.

That is, 0.02 kg / cm ² G is contained in the pressurizing chamber 3.
While supplying the cooling air of, polypropylene of MFR35 was spun at 0.21 g / min per hole from the spinneret 1 having 0.3 mmφ and 2,470 holes. The results are shown in Table 1 below. When L ₁ was shortened to 20 mm, yarn breakage occurred immediately after spinning, and spinning could not be performed. When L ₁ was set to 300 mm, the filament during spinning shook, and when L ₁ was set to 500 mm, the filaments were fused due to the shaking, and spinning could not be performed.

[0017]

[Table 1]

(Embodiment 2) In the apparatus shown in FIG.
₁ = 200 mm, L ₂ = 1,000 mm, L ₃ = 300 mm, and the length of L ₄ is 100, 150, 200, 300, ₄
Instead of 00, polypropylene of MFR35 was spun under the same conditions as in Example 1 to produce a nonwoven fabric from 1.0 denier (d) filaments, and the uniformity was used as the appearance evaluation method. The results are shown in Table 2 below.

According to this example, the filament during spinning is stable, but when L ₄ is shortened to 100 mm,
The appearance of the non-woven fabric deteriorated and the uniformity increased to 0.8. When L ₄ is increased to 400 mm, the pressure chamber is 0.02 kg / cm to obtain the same denier filament.
^It was necessary to raise from ² G to 0.03 kg / cm ² G.

[0020]

[Table 2]

Here, the homogeneity was calculated by the following formula from the basis weight and average basis weight of each material obtained by cutting out a material having a diameter of 13 mm from the thick and thin portions of the nonwoven fabric. (Uniformity) = (weight per unit weight−weight per unit weight) / (average weight per unit) (Example 3) In Example 2, the length of L ₄ is 200 mm.
Then, polypropylene of MFR 15, 35, 60 and 100 was spun under the same conditions as in Example 2 while supplying 0.01 kg / cm ² G of cooling air to the pressurizing chamber 3. The results are shown in Table 3 below.

[0022]

[Table 3]

Example 4 Instead of polypropylene, poly-4-methylpentene-1 (MFR180ASTM D
A nonwoven fabric was produced in the same manner as in Example 3 except that 1238) was used. (Example 5) Instead of polypropylene, LLDPE (D
A nonwoven fabric was produced in the same manner as in Example 3 except that ASPUN and MFR5 manufactured by OW were used. The above results are shown in Table 4 below.

[0024]

[Table 4]

[0025]

According to the method and apparatus for producing a nonwoven fabric of the present invention, the cooling air supplied to the pressurizing chamber is supplied with 0.05 kg / cm ² G.
Even at a low pressure below, a filament having a sufficient strength and a small fineness can be stably produced without causing yarn breakage or yarn wobbling. Moreover, the length of the nozzle is 150 to 300.
By setting the thickness to mm, it is possible to obtain a nonwoven fabric having excellent uniformity and excellent appearance.

If the plate constituting the nozzle can be moved back and forth, the nozzle can be opened and closed and the gap between the nozzles can be adjusted. If the open end of the nozzle is formed in an R shape, the pressure loss of the cooling air can be reduced. Can be reduced. Also, if a damper is provided at the inlet, the air volume can be adjusted.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a nonwoven fabric manufacturing apparatus according to the present invention.

FIG. 2 is a partially enlarged sectional view of the nozzle shown in FIG.

[Explanation of symbols]

1 ... Spinneret 2 ... Throat 3 ... Pressurizing chamber 4 ... Dunbar 5 ... Introducing port 6 ... Rectifying filter 7 ... Nozzle 8 ... Filament group 9 ...・ Mobile collection surface

Claims (11)

[Claims] 1. A method for producing a non-woven fabric, wherein a continuous filament made of a large number of polyolefins spun from a spinneret is cooled by cooling air introduced into a pressurizing chamber and then deposited on a moving collection surface. From 50 to 200 mm from the start to the cooling chamber, a slow cooling process in which the molecular orientation of the filament is advanced before the start of crystallization, and a filament expressing the molecular orientation is introduced into the pressure chamber at 0.05 kg / cm ² G
A method for producing a non-woven fabric, comprising the following steps of rapidly solidifying by cooling air. 2. In the rapid solidification process, cooling air of 5 to 40 ° C. introduced into the pressurizing chamber at a rate of 0.1 to 2.0 m / sec is about 10 m / sec.
The method for producing a non-woven fabric according to claim 1, which is provided by rapidly accelerating from a speed of less than a second to a speed of about 20 to 100 m / sec. 3. The method for producing a non-woven fabric according to claim 1, wherein the length of the nozzle is 150 to 300 mm. 4. The polyolefin is 230 ° C. and the load is 2.
The method for producing a nonwoven fabric according to claim 1, wherein the MFR at 160 g is 15 to 120 g / 10 minutes. 5. A pressurizing chamber having a spinneret for spinning a large number of polyolefin filaments, an inlet for cooling air, and coagulating the spun filament with the cooling air introduced through the inlet, and the above-mentioned spinning. A throat having a length of 50 to 200 mm that connects the mouthpiece and the pressurizing chamber, a nozzle having a shape that adjusts the wind speed and pressure of the cooling air in a state effective for stretching the filament, and the filament blown from the nozzle is captured. An apparatus for manufacturing a non-woven fabric, which comprises a means for gathering and intertwining. 6. The method for manufacturing an apparatus for manufacturing a nonwoven fabric according to claim 5, wherein the spinneret has a hole density of 8 holes / cm ² or less. 7. The non-woven fabric manufacturing apparatus according to claim 5, wherein the inlet is divided into one or a plurality of stages, and each stage has a damper. 8. The non-woven fabric manufacturing apparatus according to claim 5, wherein the nozzle has a length of 150 to 300 mm. 9. The non-woven fabric according to claim 5, wherein the nozzle is composed of a pair of plates arranged to face each other with an appropriate interval, and at least one of the plates is configured to be capable of advancing and retracting toward the other. Manufacturing equipment. 10. The apparatus for manufacturing a non-woven fabric according to claim 5, wherein the nozzle has a rounded open end. 11. The filament entanglement means is a needle punching machine, a heat embossing machine, or a water jet.
The nonwoven fabric manufacturing apparatus according to claim 5, comprising at least one or more.