JP2009074196A - Nonwoven fabric and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bulky nonwoven fabric having excellent heat and chemical resistances and to provide a method for producing the bulky nonwoven fabric. <P>SOLUTION: The nonwoven fabric is formed from filaments having a melting liquid crystal-forming wholly aromatic polyester having a melt viscosity of 20 Pa s or less at 310°C or above as a main component and having an average fiber diameter of 1-15 μm, and the principal plane has a plurality of peak parts 1. The apparent density of the nonwoven fabric is 0.01-0.3 g/cm. The ratio (Sm)/(Ym) of the average interval (Sm) of the apexes of the adjacent peak parts to the average height (Ym) of the plurality of peak parts may be about 0.02-100. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bulky nonwoven fabric and a method for producing the same while being excellent in heat resistance and chemical resistance. In particular, the present invention relates to a nonwoven fabric not only having excellent heat resistance and chemical resistance, but also excellent cushioning properties, wiping properties, and slip resistance, and a method for producing the same.

  Nonwoven fabrics are widely used in various fields as various industrial materials and construction materials. However, generally used nonwoven fabric raw materials are cotton, rayon, polyethylene terephthalate, polypropylene, nylon, etc., and the nonwoven fabric produced from these raw materials does not show satisfactory heat resistance and chemical resistance. It cannot be used for applications that require high functionality, such as wipers and filter aggregates that require chemical resistance.

  For example, as a nonwoven fabric excellent in heat resistance and alkali resistance, in Patent Document 1 (Japanese Patent Laid-Open No. 2005-232622), a web containing an aramid fiber and a basalt fiber is arranged on one side or both sides of a base fabric, and both needle punching is performed. A needle felt in which fibers are integrated is disclosed. This felt is excellent in heat resistance and alkali resistance, but has high hygroscopicity. In addition, the needle punch method not only cannot form irregularities on the surface, but also the manufacturing process is extremely complicated. First, fibers are manufactured, and the fibers are cut into short fibers, and then a card web is formed from the short fibers. Furthermore, a multi-step process is required in which the card web is formed into a sheet by a needle punch.

  On the other hand, as a non-woven fabric using heat- and chemical-resistant molten liquid crystal-forming wholly aromatic polyester as a raw material, Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-061064) discloses a melt liquid crystal property having an average fiber diameter of 0.6 to 20 μm. A non-woven fabric is disclosed which is made of polyester fiber and has an area shrinkage rate of 3% or less at 300 ° C. for 1 hour. This document describes that the molten liquid crystal-forming wholly aromatic polyester is melt blown to obtain a nonwoven fabric excellent in heat resistance, dimensional stability, low water absorption, and resin impregnation. However, even in this document, there is no description of obtaining a bulky and low-density nonwoven fabric.

JP-A-2005-232622 JP 2002-061064 A

An object of the present invention is to provide a nonwoven fabric that not only has excellent heat resistance and chemical resistance, but also can improve cushioning properties even if it is lightweight.
Another object of the present invention is to provide a nonwoven fabric that can further improve wiping properties and anti-slip properties.
Still another object of the present invention is to provide a method for efficiently producing a nonwoven fabric having excellent characteristics as described above.

  As a result of intensive studies in order to solve the above-described problems of the prior art, the present inventors have developed a liquid crystal-forming fully aromatic polyester polymer having a melt viscosity at 310 ° C. of 20 Pa · s or less at a high temperature and high speed. After forming a fluid, this high-temperature high-speed fluid is sprayed onto a cooled metal roll at a predetermined collection distance and is cooled and solidified and collected to cool and collect liquid crystals that are difficult to handle. It has been found that even a formable wholly aromatic polyester polymer can be easily processed, and as a result, a nonwoven fabric having surface irregularities and being bulky and excellent in heat resistance and chemical resistance can be obtained. The present invention has been completed.

That is, the present invention made on the basis of the above examination results is mainly composed of a molten liquid crystal-forming wholly aromatic polyester having a melt viscosity at 310 ° C. or higher of 20 Pa · s or less and an average fiber diameter of 1 to 15 μm. The nonwoven fabric is made of a certain filament, the main surface has a plurality of peaks, and the apparent density is 0.01 to 0.3 g / cm ³ .

  For example, the plurality of peak portions are arranged at least along the first direction, and the height of the peak portions (for the plurality of peak portions of the nonwoven fabric present in the cross section having a width of 10 cm along the first direction ( The average height (Ym) of the peaks obtained by averaging Yi) may be about 0.1 to 5 mm, and the average interval (Sm) obtained by averaging the intervals (Si) between the apexes of adjacent peaks is 0. It may be about 0.05 to 5 mm. Further, the ratio of the average height (Ym) of the peak portions to the average interval (Sm) of the apexes of the adjacent peak portions may be (Sm) / (Ym) = 0.about 0.02-100.

  Moreover, since the said nonwoven fabric is formed with the peak part, even if an apparent density is low, it is excellent in compression resistance, and in a nonwoven fabric, compression resilience (RC) is about 40 to 70%, compression rigidity (LC). May be about 0.4 to 0.7, and / or the compression ratio (EMC) may be about 5 to 30%.

Such a non-woven fabric is preferably produced by a melt blown method, and the non-woven fabric is made of a molten liquid crystal-forming wholly aromatic polyester having a melt viscosity at 310 ° C. of 20 Pa · s or less, a spinning temperature of 310 to 360 ° C., and a hot air temperature. As a high-temperature high-speed fluid of 310 to 380 ° C. and an air amount of 10 to 50 Nm ³ per 1 m width of the nozzle, it is sprayed onto a cooling metal roll having surface irregularities at a collection distance of 2 to 20 cm (preferably about 2.5 to 13 cm). It can be manufactured by collecting.

  Furthermore, in the said manufacturing method, the nonwoven fabric sprayed and collected may be further solid-phase polymerized to improve the strength of the nonwoven fabric.

  In the specification, “melted liquid crystal-forming wholly aromatic polyester” means a wholly aromatic polyester resin exhibiting optical anisotropy (liquid crystallinity) in the melt phase. The liquid crystallinity can be easily identified by heating the sample on the hot stage in a nitrogen atmosphere and observing the transmitted light.

  Further, the height (Yi) of the ridges of the nonwoven fabric and the interval (Si) between the apexes of the adjacent ridges are such that the nonwoven fabric includes a plurality of ridges arranged along the first direction. A cross section of a sample piece having a width of 10 cm along the direction is observed with an optical microscope, and measurement is performed on all the crests present in the sample width of 10 cm. In addition, when the mountain shape breaks without reaching the apex at both ends of the sample width, the broken mountain shape is not included in the height (Yi) and the interval (Si) of the mountain portion.

  In the present invention, a nonwoven fabric having a plurality of crests formed on the surface can be obtained by processing a molten liquid crystal-forming wholly aromatic polyester excellent in heat resistance and chemical resistance by a specific production method. Such a non-woven fabric not only has excellent heat resistance and chemical resistance, but also can improve cushioning properties even if it is lightweight.

Moreover, since the nonwoven fabric of this invention is excellent in heat resistance and chemical resistance, and is bulky, it can improve wiping property and chemical retention in industrial special wipers and the like.
Furthermore, the nonwoven fabric of the present invention can effectively suppress the generation of static electricity, reduce not only the amount of dust generation, but also improve the wiping property and anti-slip property of the nonwoven fabric due to the uneven shape of the surface. .

  Moreover, in the manufacturing method of the nonwoven fabric of this invention, the nonwoven fabric which has such an outstanding characteristic can be mass-produced efficiently.

  The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. The drawings are not necessarily drawn to scale, but are exaggerated in illustrating the principles of the invention. In the accompanying drawings, the same part number in the plurality of drawings indicates the same part.

[Nonwoven fabric]
The nonwoven fabric of the present invention is composed of a filament having a melt liquid crystal-forming wholly aromatic polyester having a melt viscosity at 310 ° C. or higher of 20 Pa · s or less and an average fiber diameter of 1 to 15 μm.
In FIG. 1, the schematic of the cross section of one Embodiment of the nonwoven fabric of this invention is shown. As shown in FIG. 1, the nonwoven fabric has a plurality of peak portions 1 on one main surface continuously along the first direction, and each peak portion 1 includes a peak portion 1 and a valley adjacent to the peak. It has a mountain shape consisting of parts 2 and 2.

  Each peak 1 has, as its height, distances Y1, Y2, Y3,... Yi from the valleys 2 and 2 of the peaks forming the peaks to the apex 3 of the peaks. Are separated by intervals of S1, S2, S3,... Si.

  Depending on the shape required for the nonwoven fabric, the heights of the peaks may be the same or different. The height (Yi) of the ridge is, for example, preferably about 0.01 mm to 1 cm, more preferably about 0.05 to 8 mm, and still more preferably 0, from the viewpoint of imparting wiping properties and slip resistance to the nonwoven fabric. About 0.07 to 6 mm. In addition, in the cross section in the width direction of the sample arbitrarily collected from the nonwoven fabric, the average height (Ym) of the peak portion present in the sample width of 10 cm is preferably, for example, about 0.1 to 5 mm, more preferably 0. About 3 to 4 mm, more preferably about 0.5 to 3.5 mm.

  Moreover, each space | interval between peak parts may be the same, and may differ. The distance between the peaks (Si) is preferably, for example, about 0.01 mm to 1 cm, more preferably about 0.05 to 8 mm, and still more preferably 0.00 from the viewpoint of imparting cushioning properties and compression resistance to the nonwoven fabric. It is about 1 to 6 mm. Moreover, in the cross section in the width direction of the sample arbitrarily collected from the nonwoven fabric, the average interval (Sm) between the crests existing in the sample width of 10 cm is preferably, for example, about 0.05 to 5 mm, more preferably 0. .About 1 to 4 mm, more preferably about 1 to 3.5 mm.

  The ratio between the average height (Ym) of the ridges and the average interval (Sm) between the apexes of the adjacent ridges can be selected from a wide range according to the performance required for the nonwoven fabric (Sm) / (Ym) is preferably about 0.02 to 100, more preferably about 0.1 to 80.

As shown in FIG. 2, in the main surface of the nonwoven fabric, the crests may be arranged in parallel with each other along the first direction and may exist in a wavy shape as a whole, or as shown in FIG. 3. As described above, the ridges may be arranged in a mutually reversed manner, and the cup-like ridges may be evenly scattered throughout. Moreover, according to the shape calculated | required by the nonwoven fabric, the peak part may exist in the main surface of a nonwoven fabric at random.
Note that the first direction is usually selected so as to include the largest number of peaks, and when the peaks are formed in a wavy shape as shown in FIG. 2, the first direction is the ridgeline of the peaks. It is set in the X direction on the paper surface so as to be orthogonal.
In addition, when the cup-shaped ridges are uniformly scattered as shown in FIG. 3, the ridges are arranged not only in the first direction but also in other directions, but the first direction Is set in the Y direction on the paper surface so as to include the most peaks.

  Moreover, as shown in FIG. 4, the non-woven fabric usually forms peaks on both the upper surface and the lower surface, which are the main surfaces of the non-woven fabric. And the positions are aligned with the width direction of the nonwoven fabric.

The nonwoven fabric of the present invention can be made bulky by a plurality of peaks, and the nonwoven fabric has an apparent density of about 0.01 to 0.3 g / cm ³ , preferably an apparent density of 0.015. ~0.2g / cm ³ or so, more preferably 0.02~0.1g / cm ³ or so, particularly preferably 0.025~0.05g / cm ³ order.

  Although the nonwoven fabric of this invention can be made into various thickness as needed, the thickness of a nonwoven fabric is from the viewpoint of cushioning property or wiping property, Preferably it is about 0.5 mm-1 cm, More preferably, it is 1-8 mm. Degree.

The cushioning property of the nonwoven fabric can be represented by the compression resistance of the nonwoven fabric. For example, when measured using a KES compression tester (manufactured by Kato Tech Co., Ltd.), the compression resilience (RC) of the nonwoven fabric is 40. About 70% is preferable, and about 50-60% is more preferable. The compression stiffness (LC) is preferably about 0.4 to 0.7, and more preferably about 0.5 to 0.6. The compression ratio (EMC) is preferably about 5 to 30%, and more preferably about 10 to 20%.
The compression resilience (RC), compression stiffness (LC) and compression rate (EMC) are as follows: speed: 0.02 cm / sec, compression area: 2 cm ² , SENS: 2 × 10 (20 g × 10 V) ), Compression load: a value obtained by compressing under the condition of 50 gf / cm ² .

(Molten liquid crystal forming wholly aromatic polyester)
The melted liquid crystal-forming wholly aromatic polyester used in the nonwoven fabric of the present invention is not particularly limited as long as the melt viscosity at 310 ° C. is 20 Pa · s or less. For example, p-hydroxybenzoic acid and 1,6-hydroxynaphthoic acid are used. Examples include acid condensates and copolymers thereof, and polyesters having structural units as shown in the following chemical formula.

  A wholly aromatic polyester having a melt viscosity at 310 ° C. exceeding 20 Pa · s is not preferable because it is difficult to make ultrafine fibers, oligomers are generated during polymerization, and troubles occur during polymerization and granulation. On the other hand, if the melt viscosity is too low, fiberization is difficult, and it is desirable that the melt viscosity is preferably 5 Pa · s or more at 310 ° C. When expressed in terms of intrinsic viscosity, the wholly aromatic polyester used in the present invention desirably has an intrinsic viscosity (ηinh) of 6.0 or less, and preferably 3.0 to 6.0. A melt liquid crystal-forming wholly aromatic polyester having such a melt viscosity can be produced by a conventionally known polymerization technique of wholly aromatic polyester, and “Vectra” (registered trademark) A, L type from Polyplastics Co., Ltd. Etc. are provided.

  The molten liquid crystal-forming wholly aromatic polyester may be used by adding other polymers, additives, and the like as long as the strength does not substantially decrease. For example, examples of additives include stabilizers (for example, antioxidants, ultraviolet absorbers, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, dispersants, fluidizing agents, and the like. These additives can be used alone or in combination of two or more.

[Method for producing nonwoven fabric]
The nonwoven fabric of the present invention can be produced by using the molten liquid crystal-forming wholly aromatic polyester and utilizing a flash spinning method, a melt blown method or the like. The melt blown method is preferable because it can relatively easily produce a nonwoven fabric made of ultrafine fibers, and can minimize the influence on the environment without requiring a solvent during spinning.

  FIG. 5 shows an outline of the production process of the nonwoven fabric of the present invention by the melt blown method. First, the melted liquid crystal-forming wholly aromatic polyester is melted by an extruder and enters a molten state toward the nozzle 5. On the other hand, heated hot air is injected from the hot air injection grooves 6 and 6 provided on both sides of the nozzle 5, and the polyester is used as the high-temperature high-speed fluid 7. The high-temperature and high-speed fluid 7 is sprayed onto a cooling metal roll 8 having surface irregularities, then taken up by a take-up roll 9 and taken up by a take-up roll 10.

For example, the molten liquid crystal-forming wholly aromatic polyester has a high temperature under spinning conditions of a spinning temperature of 310 ° C. to 360 ° C., a hot air temperature (primary air temperature) of 310 ° C. to 380 ° C., and an air amount of 10 to 50 Nm ³ per 1 m width of the nozzle. It becomes the high-speed fluid 7 and is sprayed from the nozzle 5 onto the cooling metal roll 8 having surface irregularities at a collection distance of 2 to 20 cm (preferably about 2.5 to 13 cm).

  This metal roll has an uneven shape corresponding to the shape of the nonwoven fabric, and its surface is cooled by a known or conventional cooling means. In this example, the concavo-convex shape has convex portions 11 and concave portions 12 extending in parallel to the axial direction of the roll 8 and alternately formed in the circumferential direction, as shown in FIG. Since the metal roll is cooled, even a melted liquid crystal-forming wholly aromatic polyester heated at a high temperature can be quickly cooled and solidified, and a desired shape can be imparted to the nonwoven fabric.

  Since it is formed by such a manufacturing method, the nonwoven fabric of the present invention is formed from substantially continuous filaments. Moreover, from a viewpoint of web formation of a nonwoven fabric, an average fiber diameter needs to be about 1-15 micrometers, Preferably it is about 3-10 micrometers. In addition, in this invention, an average fiber diameter refers to the average value of the value which magnified and imaged the nonwoven fabric with the scanning electron microscope, and measured the diameter of arbitrary 100 fibers.

  Furthermore, in the production method of the present invention, in order to improve the strength of the nonwoven fabric, the obtained nonwoven fabric may be further heat-treated to proceed with solid phase polymerization in a fibrous form. Since the non-woven fabric of the present invention is composed of ultrafine fibers and the specific surface area is remarkably increased, by-products generated with the progress of polymerization can be easily detached, and the polymerization reaction can be carried out very efficiently.

  In the solid phase polymerization, depending on the characteristics of the melt liquid crystal forming polyester to be used, an inert gas such as nitrogen is used, the treatment is performed in the air, or the solid phase polymerization is first performed in the inert gas. It is possible to select as appropriate, for example, to complete solid phase polymerization in air.

  In particular, molten liquid crystal forming polyester often undergoes cross-linking reactions such as dehydrogenation and oxygen cross-linking when proceeding with solid-phase polymerization in the air, and further improves the chemical resistance, water resistance and heat resistance of the nonwoven fabric. Can do. When these reactions are expected, it is preferable to proceed with solid-state polymerization in an inert gas in the initial stage to increase the molecular weight and then proceed with the reaction in air.

  If necessary, a method of managing the oxygen concentration, for example, selecting a reaction in air having an oxygen concentration of 10% can be exemplified as one of the options. It is also possible to advance the solid-phase polymerization reaction in an inert gas such as nitrogen in the initial stage, to make an aerobic atmosphere at the stage when the degree of polymerization is increased, and further proceed the reaction such as crosslinking and carbonization. .

  The nonwoven fabric of the present invention is excellent in heat resistance and chemical resistance because it contains a specific molten liquid crystal forming wholly aromatic polyester as a main component. Furthermore, since not only the average fiber diameter is 1 to 15 μm but also has a specific uneven shape, the specific surface area of the nonwoven fabric can be increased. Furthermore, not only the cushioning property (or compression resistance) can be improved by imparting strength to the nonwoven fabric by a specific shape, but the wiping property and anti-slip property can be improved by the shape.

  Such non-woven fabrics can be used as various wiping materials (for example, industrial wipers, daily use wipers, etc.) taking advantage of chemical resistance and wiping properties, as well as heat resistance, chemical resistance and specific surface area. It is also useful as various filter aggregates by taking advantage of this increase.

Furthermore, it is useful as various curing sheets (for example, a curing sheet for floors) by taking advantage of heat resistance, chemical resistance, cushioning properties and anti-slip properties.
Moreover, even if it is light, since it is excellent in cushioning properties, it can also be used effectively as a packaging material for packaging electronic components such as semiconductors.
Furthermore, it is useful as various work gloves (for example, work gloves for electronic parts) by taking advantage of chemical resistance and anti-slip properties utilizing surface irregularities.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. The physical properties of the nonwoven fabric were measured by the following measuring methods.

(Melt viscosity Pa · s)
Measurement was performed under the conditions of a temperature of 310 ° C. and a shear rate of r = 1000 ⁻¹ using a Toyo Seiki Capillograph Type 1B.

(Evaluation of chemical resistance)
It was immersed in o-chlorophenol at 30 ° C. for 24 hours, and the degree of dissolution was confirmed visually. Further, boiling treatment was performed for 1 hour in a 1N aqueous sodium hydroxide solution, and the weight reduction rate was confirmed. In the present invention, “substantially insoluble in a solvent” means that it is insoluble in o-chlorophenol, and even if the boiling treatment is carried out for 1 hour in a 1N aqueous sodium hydroxide solution, the weight reduction rate is reduced. It means 10% or less.

(Evaluation of heat resistance)
A hot air of 100 ° C. was passed through the nonwoven fabric, and the presence or absence of a shape change was confirmed visually. When the shape did not change, it was determined that the heat resistance was good, and when the shape changed, it was determined that the heat resistance was poor.

(Measurement of heat distortion temperature)
Using TMA-50 manufactured by Shimadzu Corporation, the sample length is set to 20 mm, 1 g per 1 g of the sample weight to be measured is given, and the temperature is raised from room temperature at a heating rate of 5 ° C./min. Let it be the heat distortion temperature. The temperature was defined by the intersection of tangent lines from the temperature-elongation curve.

(Crest height and crest spacing mm)
A 100 × 100 mm test piece was taken from the sample length direction, and a cross section in the width direction of the test piece was observed with an optical microscope. The height of the peak portion was measured for all the peak portions existing in the sample width of 10 cm. (Yi) and the space | interval (Si) of the vertex of the adjacent peak part were measured with the optical microscope (the Keyence Corporation make, VHX-10). Then, the average height (Ym) of the peak portions was obtained by averaging the heights of the obtained peak portions, and the average interval (Sm) was calculated by averaging the intervals (Si) between the apexes of the adjacent peak portions. .

(Thickness μm)
A 100 × 100 mm test piece was taken from the sample length direction and measured with a dial thickness gauge.

(Average fiber diameter μm)
A 100 × 100 mm test piece is taken from the sample length direction, and the obtained test piece is enlarged and photographed with a scanning electron microscope, and after measuring the diameter of an arbitrary 100 fibers, an average value thereof is calculated. did.

(Weight per unit g / m ² )
A test piece of 100 × 100 mm was taken from the sample length direction, the mass in a moisture equilibrium state was measured, and calculated per 1 m ² .

(Apparent density g / cm ³ )
The apparent density was calculated by dividing the basis weight by the thickness.

(Compression resilience (RC)%, compression stiffness (LC), compression rate (EMC)%)
Measurement was performed using a KES compression tester (manufactured by Kato Tech Co., Ltd.), and the compression resilience (RC), compression stiffness (LC) and compression rate (EMC) of the nonwoven fabric were measured. The measurement was performed under the conditions of speed: 0.02 cm / sec, compression area: 2 cm ² , SENS: 2 × 10 (20 g × 10 V), and compression load: 50 gf / cm ² .

Example 1
Liquid crystal-forming wholly aromatic polyester (VECTRA-A type manufactured by Polyplastics Co., Ltd .; melt viscosity at 310 ° C. 10 Pa · s, intrinsic viscosity 5.8) was sufficiently dried with a low dew point air dryer. The mixture was extruded by a shaft extruder and supplied to a melt blown nonwoven fabric manufacturing apparatus having a nozzle having a width of 1 m and a hole number of 1000. In a melt blown device, a single-hole discharge rate of 0.3 g / min, a resin temperature of 320 ° C., a hot air temperature of 320 ° C., and an air amount of 30 N per 1 m width of the nozzle is captured on an uneven cooling metal roll cooled by a water-cooled pipe. The melt blown nonwoven fabric was obtained by spraying at a gathering distance of 5 cm, winding after cooling and solidification. The obtained nonwoven fabric had peaks on both the upper and lower surfaces, and had the characteristics shown in Table 1.

(Comparative Example 1)
Instead of spraying and collecting on an uneven cooling metal roll cooled by a water-cooled pipe, which is the collecting method performed in Example 1, a method of collecting by suction on a net at a collection distance of 15 cm A nonwoven fabric was obtained in the same manner as in Example 1 except that was adopted. The obtained nonwoven fabric was flat on both the upper and lower surfaces and had the characteristics shown in Table 1.

As shown in Table 1, even if the nonwoven fabric obtained in Example 1 had a basis weight of 70 g / m ² , the nonwoven fabric was bulky because of unevenness, and the thickness could be increased, and the apparent density could be reduced. Further, since the compression resilience and compression stiffness were large and the compression rate was small, the cushioning property was high and the compression resistance was excellent. Furthermore, the nonwoven fabric obtained in Example 1 was excellent in chemical resistance and heat resistance.
On the other hand, the nonwoven fabric obtained in Comparative Example 1 had the same basis weight, but was flat with no irregularities, thinner than the nonwoven fabric obtained in Example 1, and higher in apparent density. Moreover, although chemical resistance and heat resistance were comparable to Example 1, since compression resilience and compression rigidity were small and a compression rate was large, it was inferior to compression resistance of the nonwoven fabric of Example 1.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings. However, various additions, modifications, or deletions can be made without departing from the spirit of the present invention, and these are also included in the present invention. It is included in the range.

It is the schematic which shows the cross section of one Embodiment of the nonwoven fabric of this invention. It is a schematic perspective view of one Embodiment of the nonwoven fabric of this invention. It is a schematic perspective view of other embodiment of the nonwoven fabric of this invention. It is the schematic which shows the cross section of different embodiment of the nonwoven fabric of this invention. It is the schematic which shows the manufacturing process by the melt blown method of the nonwoven fabric of this invention. It is the elements on larger scale of the cooling metal roll described in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1 '... Mountain part 2, 2' ... Valley part 3, 3 '... Peak vertex Yi ... Height of mountain part Si ... Spacing between mountain parts 4 ... Molten molten liquid crystal forming wholly aromatic polyester DESCRIPTION OF SYMBOLS 5 ... Nozzle 6 ... Hot-air injection groove 7 ... High-temperature high-speed fluid 8 ... Cooling metal roll 9 with surface unevenness ... Take-up roll 10 ... Winding roll 11 ... Convex part 12 ... Concave part

Claims (7)

It consists of a filament having a melted liquid crystal forming wholly aromatic polyester having a melt viscosity at 310 ° C. or higher of 20 Pa · s or less and an average fiber diameter of 1 to 15 μm, and the main surface has a plurality of peaks. The nonwoven fabric whose apparent density is 0.01-0.3 g / cm < ³ >.   The plurality of peak portions according to claim 1, wherein the plurality of peak portions are arranged along at least the first direction, and the plurality of peak portions of the nonwoven fabric existing in a cross section having a width of 10 cm along the first direction The average height (Ym) obtained by averaging the heights (Yi) is 0.1 to 5 mm, and the average interval (Sm) obtained by averaging the intervals (Si) between the apexes of the adjacent peaks is 0.05 to 5 mm. Non-woven fabric.   3. The nonwoven fabric according to claim 2, wherein the ratio of the average height (Ym) of the ridges to the average interval (Sm) between the apexes of adjacent ridges is (Sm) / (Ym) = 0.02-100.   In any one of Claims 1-3, the compression resilience (RC) of the said nonwoven fabric is 40 to 70%, compression rigidity (LC) is 0.4 to 0.7, and / or compression rate (EMC). Nonwoven fabric that is 5-30%.   The non-woven fabric according to any one of claims 1 to 4, wherein the non-woven fabric is produced by a melt blown method. A molten liquid crystal-forming wholly aromatic polyester having a melt viscosity at 310 ° C. of 20 Pa · s or less is heated at a spinning temperature of 310 to 360 ° C., a hot air temperature of 310 to 380 ° C., and an air amount of 10 to 50 Nm ³ per 1 m width of the nozzle. The manufacturing method of the nonwoven fabric as described in any one of Claims 1-5 which sprays and collects on the cooling metal roll which has a surface unevenness | corrugation with a collection distance of 2-20 cm as a high-speed fluid.   The production method according to claim 6, wherein the sprayed and collected nonwoven fabric is further subjected to solid phase polymerization.

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