JPH04163357A - Production of nonwoven fabric - Google Patents

Abstract

PURPOSE:To obtain the subject uniform nonwoven fabric excellent in permeability and filter characteristics and having a high tensile strength by widening a fiber stream using an air current-control guide, distributing the accompanying air current back and forth using a collecting plane and fixing a nonwoven fabric on the convex surface of the collecting plane. CONSTITUTION:A fiber stream 4 is widened by a function of an air current- control guide 43 and accumulated on a drawing net 6 moving on a collecting surface 11 composed of a convex-shaped part 8 and inclined plane parts 9 and 10 smoothly connected thereto utilizing a suction force produced from a blower 18, thus obtaining the objective nonwoven fabric.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention jets out a molten thermoplastic resin spun from a plurality of spinning holes from a gas jetting slit arranged adjacent to the spinning holes. This invention relates to a method for producing a nonwoven fabric having ultrafine edges by pulling and thinning with high-speed airflow to form a fiber stream of ultrafine fibers, and then collecting and accumulating the fiber stream.

(Prior art) A conventional method for manufacturing nonwoven fabrics is to melt-spun a thermoplastic resin, pull and thin it using high-speed airflow, form a fiber stream, and then collect and accumulate this fiber stream. There are techniques disclosed in JP-A-49-48921 and JP-B-80-56825.

In the former technique, as shown in FIG. 2, the thermoplastic resin is supplied to a hopper 16, passed through an extruder 1 and a gear pump 2, and then supplied in a constant quantity to a die 23, and then through a plurality of spinning holes 26 built into the die 23. Continuous spinning with high speed airflow #24
After passing through the spinning hole 26, the spun yarn is pulled and thinned by a high-speed airflow ejected from the gas ejection slit 25 arranged adjacent to the spinning hole 26, forming a fiber stream 27 of ultra-fine fibers, which is then deposited on a collection plate 29 on a flat surface. A moving take-up net 30'' is used to accumulate and wind up the items.

Furthermore, as shown in FIG. 3, the latter technique allows a fiber flow 36 of ultrafine fibers to be moved in the direction of movement of the collection plate 37 from a contact area where the collection plate 37 and the holding plate 38 are in contact with each other via the fibers. The fiber stream 36 is sprayed and accumulated between the collecting plate 37 and the holding plate 38, which are provided so that the gap between the collecting plate and the holding plate in the opposite direction increases as the distance from the contact portion increases. At least one of the collection plate 37 and the holding plate 38 has a porous structure, and if necessary, the fiber flow 36 is suctioned from the back side with a blower 18 or 41. This is an attempt to increase the agglomeration effect.

In addition, 17 is a motor, 32 is a die, 33 is a high-speed air flow source, 34 is a gas jetting slit, 35 is a spinning hole, and 40 is an entrained flow.

(Problems to be Solved by the Invention) However, the conventional technology has the following problems. Second
In the method shown in the figure, the accumulated fibers are scattered under the influence of the entrained flow 28 generated when the high-speed airflow that pulls the plastic resin paste entrains the atmosphere, so in order to form a nonwoven fabric, it is necessary to Is it necessary to keep a sufficient distance from 29? Therefore, the nonwoven fabric formed by this method takes a long time to collect the fiber flow, resulting in a nonuniform nonwoven fabric containing a patchy structure formed by intertwining a large number of fibers. The texture as a textile product, the permeation performance and filtration performance as a filter are far beyond expectations.

Furthermore, in the method shown in FIG. 3, the spinning hole 35 and the collection plate 37 are
There is no particular limit to the distance between the fibers 36 and the fibers 36 can be collected at a position close to the spinning hole 35, so that the above-mentioned string-like structure is not formed. Due to the manufacturing method, the obtained nonwoven fabric has a laminated structure 42 that is perpendicular to or close to the flow direction of the manufacturing line, as shown in the cross-sectional view of FIG. 4, and the tensile strength in this direction is extremely low. . As a countermeasure to the above, a method has been taken in which the nonwoven fabric is entangled with high-speed fluid ejected from a needle punch or a large number of fluid ejection holes arranged facing the nonwoven fabric in the post-processing process to improve its tensile strength. Processing damages the nonwoven fabric and reduces its feel as a textile product and its permeability and filtration performance as a filter, so it is not at all preferable due to the manufacturing method.

Furthermore, in the methods shown in FIGS. 2 and 3, since a negative pressure region is generated in the gas jetting portion, the atmosphere flows into the negative pressure region to form an entrained airflow having a velocity component directed toward the center of the fiber flow.

As a result, the streamlines at both ends of the fiber flow in the width direction move toward the center, so that the width of the fiber flow decreases toward the downstream.

The basis weight of the nonwoven fabric collected in this state is smaller at both ends in the width direction than at the center, and uniformity of quality and performance over the entire width cannot be expected.・As a result of intensive studies on the process of collecting fiber streams and making them into nonwoven fabrics, the inventors found that in order to obtain a nonwoven fabric with good spreadability, uniformity, and sufficient tensile strength for practical use, it was found that It is necessary to introduce the fiber into the control guide and widen the fiber flow width, which has been reduced due to the entrained airflow to the collection plate, to its original width, and then spray the fiber flow at an angle close to perpendicular. The present invention was developed based on the discovery that a curved surface is more effective than a flat surface in suppressing the influence of entrained airflow accompanying the fiber flow and fixing the fibers in the fiber flow on the collection plate. be.

The present invention has excellent permeation performance that was not achieved by conventional methods, and has excellent filtration performance and tensile strength.
Furthermore, the present invention aims to provide a manufacturing method capable of manufacturing a nonwoven fabric with excellent width direction uniformity and basis weight distribution in these properties.

(Means for Solving the Problem) The present invention takes the following means to solve the problem. That is, in the present invention, the molten thermoplastic resin spun from a plurality of spinning holes is pulled and purified by a high-speed air stream 1 ejected from a gas jet slit located adjacent to the spinning holes. to form a fiber stream of ultrafine fibers, then collect and accumulate the fibers -/A, and
In a method for manufacturing a nonwoven fabric made of fibers, an air flow control guide is provided below a fiber flow forming part, the gap in a direction perpendicular to the fiber flow becomes smaller as it goes downstream, and the fiber flow is introduced into the air flow control guide. After widening, the fiber stream is discharged, and a porous collection surface consisting of a convex curved surface and sloped surfaces extending downward on both sides of the convex curved surface, the back surface of which has a suction structure, is placed below the fiber flow. and further applicable)
11) The surface of the collecting surface is provided so that a collecting net is moved, and while the collecting net is moved forward, the fibers are transferred to the convex curved surface portion of the collecting surface via the collecting net. This method of manufacturing a nonwoven fabric is characterized in that the fiber flow is directed and blown out, and the fiber flow is collected and accumulated on a moving take-up and soot.

The present invention will be explained below with reference to the drawings.

FIG. 1(A) shows a front view of the nonwoven fabric manufacturing method according to the present invention, and FIG. 1(B) shows a partial view of the vicinity of the airflow control guide when FIG. 1(A) is viewed from the inlet direction. However, the present invention is not necessarily limited to this specific example.

Thermoplastic resins such as polyolefin, polyester, polyamide, polyurethane, polyacrylic, polyfluoroethylene, and polyvinyl chloride resins are the first.
In the figure (a), it is supplied to the puncher 16, and the extruder 1
, a fixed amount is supplied to the die 3 via the gear pump 2, and is continuously spun from a plurality of spinning holes 22 built into the die 3. A gas ejection slit 21 connected to a distant gas source 20 is arranged adjacent to the spinning hole 22, and the spun yarn from the spinning hole 22 is pulled and thinned by the high-speed airflow ejected from the gas ejection slit 21. A fiber stream of microfibers is formed.

After the fiber flow is widened by the airflow control guide 43, the convex curved surface section 8 and the inclined surface sections 9, 1 smoothly connected thereto.
The non-woven fabric made of ultrafine fibers is collected on a take-up net 6 that moves in close contact with a porous collection surface 11 that is sucked from the back side by a blower 18. This nonwoven fabric moves together with the collection net 6, and the collection surface 11 is
[After being separated from the take-up net 6 at this position, the product is wound up onto a take-up roll 12 to become a product.

The width of the air flow control guide 43 is, for example, 2
0Q mm plus length, preferably 50 to 200 mm, and opening angle of 15 to 30 degrees.

The quality of the abrasive material is not particularly limited as long as it can withstand the impact and heat of the fiber flow and has a smooth surface. The position of the airflow control guide 43 may be related to its opening angle, and is preferably 100 to 300 mm from the upper surface of the I'ili collector 8.

The shape of the convex curved surface portion 8 of the collection surface 11 has a radius of 100 to 2, for example.
A portion of the cylindrical side surface of 0.00 mm is preferably considered, but is not particularly limited thereto.

In addition, the length of the inclined surface portions 9 and 10 is 500°-9, respectively.
= 200 mm or more is preferable.

The collection surface 11 has a porous structure, and suction is performed from the back surface using a blower 18 with one pumping force as required, thereby enhancing the effect of accumulating the fiber flow. From this point of view, this suction method is preferable. In the case of suction using the blower described above, a plurality of blowers or filters 19, 19' are used.

19'', it is possible to distribute the suction force between or within each part of the collection surface 11, and the suction pressure at each position can be set to the minimum suction pressure necessary for forming the nonwoven fabric. is possible.

A preferable example of the porous structure of the collection surface 11 is 5 to 3
A metal or plastic net-like structure with a diameter of 3 to 5 mm and a porosity of 30% or more (panochink play) of the above-mentioned quality can be drilled.

Moreover, as a preferable example of the take-up net 6, 20 to 10
A mesh structure made of metal, plastic, or plastic can be drilled. Particularly preferred is one whose surface is coated with a slippery component such as Teflon.

In FIGS. 1 and 2, the fiber stream 4 is blown onto the convex curved surface portion 8 of the collection surface 11, preferably approximately perpendicularly to the apex portion, or the approximately apex portion is blown not only at the top but also at a slightly inclined surface portion. 9,
This includes a case where the fiber flow 4 is blown approximately vertically with a deviation toward 10. For example, when the convex curved surface part is a cylindrical surface, it is preferable to horizontally rearward from the top of the convex curved surface part, where R is the radius of the convex curved surface part.

(effect) The above technical means works as follows.

When the atmosphere flows into the negative pressure region generated below the gas ejection slit 21, an entrained airflow 14 is generated. Since this entrained airflow 14 has a component directed toward the center of the fiber flow 4 as shown in FIG. 1(b), the width of the fiber flow decreases as it goes downstream. When a fiber flow with a reduced width is introduced into the air flow control guide 43, the distance between the guide in the direction perpendicular to the fiber flow decreases as it goes downstream, so the fiber flow is regulated by this guide and its width increases. . Therefore, it is possible to restore the lost fiber flow width by the entrained air flow 14, and it is possible to collect the fiber flow width during spinning, thereby making it possible to obtain a nonwoven fabric with a uniform basis weight.

Moreover, the collection surface 11 functions as follows. The entrained airflow 44 that accompanies the fiber flow 4 discharged from the airflow control guide collides with the convex curved surface portion 8 of the collection surface 11 and is distributed before and after the convex curved surface portion 8 of the collection surface 11 . The nonwoven fabric formed by spraying is pulled back and forth. The resultant force of this tensile force fixes the nonwoven fabric on the convex curved surface portion 8 of the collection surface 11, so that it is possible to collect the fibers at a position close to the spinning hole 22. In the prior art shown in FIG. All of the string-like structures formed by entanglement disappear, and a uniform nonwoven fabric can be obtained. In addition, the suction force required for the convex curved surface portion 8 of the collection surface 11 is extremely small compared to the conventional technology.
Shows great effect in reducing blower power consumption.

By the above-mentioned collection method, the fiber stream 4 is arranged so as to have a laminated structure that is almost horizontal to the flow direction of the production line on the convex curved part of the collection surface 11, so that the obtained nonwoven fabric has a practically sufficient tensile strength. Has strength.

The inclined surface portions 9 and 10 connected to the convex curved surface portion 8 of the collection surface 11 function as follows. The fiber flow is caused by the convex curved surface portion 8 of the collection surface 11.
At the top, it becomes a non-woven fabric, but at the position beyond the convex curved surface section 8, the entrained airflow 1 is distributed to the front and rear by the convex curved surface section 8.
5, all or part of the nonwoven fabric peels off from the take-up net. This not only disturbs the nonwoven fabric and reduces its quality, but also makes it impossible to roll it up into products in some cases. In the present invention, the convex curved surface portion 8 of the collection surface 11
By arranging inclined surface parts 9 and 10 before and after the nonwoven fabric and suctioning from the back surface thereof using a blower 18, peeling of the nonwoven fabric can be prevented and a homogeneous product can be obtained.

Between each part 8, 9.10 of the collection surface 11 or each part 8°9.1
Since the suction pressure can be distributed within 0, it is possible to set the suction pressure at each position to the minimum suction pressure necessary for forming the nonwoven fabric. Therefore, the power consumption of the blower used can be reduced, which has a significant effect on reducing manufacturing costs.

(Example) Example 1 A nonwoven fabric was produced using polyethylene terephthalate with an intrinsic viscosity of IV 0.61 (measured at 30°C in a mixed solution of phenol/tetrachloroethane-6/4) using the collection equipment shown in Figure 1. did.

The width of the airflow control guide 43 is 200mm to the gas ejection slit.
Add mm, length is 100mm, interval is entrance part 10
0 m- and an opening angle of 20° was used.

The convex curved surface part 8 of the collection surface 11 is a 1/4 part cylinder with a radius of 100 mm, and the inclined surface parts 9 and 10 have a length of 800 m and a length of 40 m, respectively.
A flat plate of 0II11 was used. The porous structure of the collection surface 11 has a diameter of 51I11. A stainless steel punching plate with an aperture ratio of 50% was used, and a 50 mesh stainless steel take-up net was used.

In addition, the fiber flow collection position was set at 300 W below the spinning hole.

Each part 8, 9 and 10 of the collection surface 11 is subjected to a static pressure of 20I.
100,100III water was poured and suctioned to collect the polyethylene terephthalate fiber stream.

The physical properties of the nonwoven fabric obtained by the method described in 1 are shown in Table 1. The conventional method in Table 1 is a method similar to that shown in FIG. 2, and the spun thread No. 1 is the method according to the present invention.

In conventional method 1, a punching plate 1 made of stainless steel with a diameter of 51 nm and an aperture ratio of 50% is used as a collecting plate, and the distance from the spinning hole is 100,100 degrees! =I did.

Furthermore, the same take-up net as used in the method of the present invention was used.

It has been found that the nonwoven fabric obtained by the method of the present invention has superior properties in terms of tensile strength, permeability, and permeability compared to nonwoven fabrics obtained by the conventional method.

Note that the physical properties in Table 1 were measured by the following methods.

Single yarn denier: Under a microscope equipped with a digital micrometer at a magnification of 400x, n=1007! III was determined and the average value was calculated.

Weight (g/m): 20 cm x 20 sheets
The sample was cut into cm pieces, weighed, and multiplied by 25.

Transmission performance: A sample was set in a column with an effective response area of 19.6 c sound (diameter 5 c), and the wind speed was J, Ocm/! I
! Static pressure in front and behind the sample (m
mAq) was calculated.

4. Public bath performance: Test A'- using the same equipment as in the case of permeation performance.
The number of floating dust particles in the airflow after Ijlii was measured using a light scattering dust counter (KC- manufactured by Rion (ltsu)).
01A) and calculated from the ratio of the two.

Tensile strength: In accordance with the general textile testing method of JIS L-1096-1979, the tensile strength was measured using a medium length of 2.5 cm and a grip distance of lQc sum.

Table 1 Polyethylene terephthalate IV O,6
1 (Effects of the Invention) The present invention has the following unique effects.

(1) The airflow control guide, whose distance in the direction perpendicular to the fiber flow decreases as it goes downstream, widens the fiber flow and collects it with the same width as when the fiber flow continues, making it possible to obtain a highly uniform nonwoven fabric. It will be done.

C) The entrained airflow that accompanies the fiber flow is distributed back and forth by the collection surface and fixes the nonwoven fabric to the convex curved surface of the collection surface, making it possible to collect the fibers at a position close to the spinning hole, resulting in a large number of fibers being collected. There is no string-like structure formed by entangled fibers, and a nonwoven fabric that is entangled or uniform can be obtained.

(3) The fiber flow is arranged so as to have a laminated structure near the flow direction of the production line at the convex curved part of the collecting surface, and the nonwoven fabric has a practically sufficient tensile strength without any post-processing. or can be obtained.

(4) The suction force required to collect the fiber stream is extremely small compared to conventional methods, and this method has a significant effect on reducing power costs required for suction blowers.

[Brief Description of the Drawings] Figure 1 (a) is a front view of the device showing an embodiment of the present invention, and Figure 1 (b) is a partial view of the airflow control guide (= partial view near J) as seen from the inlet direction. Figures 2 and 3 are front views of the equipment used in the conventional method;
FIG. 4 shows a cross-sectional view of a nonwoven fabric obtained by a conventional method. 2... Gear pump, 8... Convex curved surface part. 3...Die, 9. IQ...Slope part. 21... Gas ejection slit, 11... Collection surface. 22... Spinning hole, 27... Fiber flow. 4...Fiber flow, 30...Takeover net. 6... bow j catch net, 36... fiber flow. 40... Airflow control guide, 37... Collection plate. Patent applicant: Toyobo Co., Ltd. East section

Claims (1)

[Claims] The molten thermoplastic resin spun from a plurality of spinning holes is pulled and thinned by a high-speed air stream jetted from a gas jetting slit adjacent to the spinning holes to form a fiber stream of ultrafine fibers, and then In the method of collecting and accumulating the fiber flow to produce a nonwoven fabric made of ultrafine fibers, an air flow control guide is provided below the fiber flow forming section and the distance in the direction perpendicular to the fiber flow decreases as it goes downstream; The fiber flow is introduced into the airflow control guide, widened and then discharged, and the surface is made of a porous surface consisting of a convex curved surface and sloped surface sections extending downward on both sides of the convex curved surface, and the back surface thereof has a suction structure. A collection surface is provided below the airflow control guide, and the surface of the collection surface is provided so that a take-up net moves, and while the take-up net is moved forward, air is collected through the take-up net. A method for producing a nonwoven fabric, comprising directing and blowing a fiber stream discharged from the airflow control guide onto the convex curved surface portion of the collection surface, and collecting and accumulating the fiber stream on a moving take-up net. .