TW201643289A - Single-layer or multilayer nonwoven fabric of long polyester fibers, and filter comprising same for food - Google Patents

Abstract

Provided are: single-layer or multilayer nonwoven fabric of long polyester fibers which is excellent in terms of transparency, dimensional stability, powder leakage property, and component extraction property; and a filter for foods which comprises the nonwoven fabric. The single-layer or multilayer nonwoven fabric of long polyester fibers according to the present invention has a content of inorganic particles of 0-100 ppm and a 10%-cumulation pore diameter less than 1,000 [mu]m, the difference between the 10%-cumulation pore diameter and the 2.3%-cumulation pore diameter being 500 or less, and has a basis weight of 10-30 g/m2.

Description

Single or multi-layer polyester long-fiber non-woven fabric and food filter using the same

The present invention relates to a single-layer or multi-layer polyester long-fiber non-woven fabric excellent in transparency, dimensional stability, powder leakage property, and component extractability, and a food filter for extracting beverages using the same.

Previously, a non-woven fabric containing a resin such as polyethylene, polypropylene, polyester, polyamide or the like was used as a packaging material. However, in order to make full use of the shielding function such as the filterability of the non-woven fabric, it is required to make the fibers dense, and it is impossible to confirm the inside. Further, in the case of extracting components such as black tea, green tea, and oolong tea, the tea bag method is often used as a simple method. The packaging materials used for tea bag applications usually use paper in a large amount, but there is a problem that the transparency is deteriorated and the contents of the packaging material cannot be seen, and heat sealing processing cannot be performed.

Patent Document 1 below discloses a non-woven fabric for tea bags having improved transparency, but there is no description relating to dimensional stability, and no particular attention has been paid. Further, the maximum pore diameter measured by the bubble point method (JIS-K-3832) is used as an evaluation of powder leakage, but the pore diameter range suitable for measurement is in the range of nanometers to micrometers, and the pore diameter is expressed by converting the pressure. Therefore, it is not suitable for the evaluation method of the tea used in practice.

Further, Patent Document 2 below discloses a biodegradable monofilament for tea bags containing a polylactic acid having a fineness of 15 to 35 dtex, which has high transparency and high transparency, but has a boiling water shrinkage ratio of monofilament. Less than 20% and the problem of low dimensional stability.

Further, Patent Document 3 below discloses that a polyolefin-based polymer is included as a non-woven fabric excellent in heat sealability of a core-sheath type composite long fiber having a sheath component and a polyester-based polymer having a melting point higher than the sheath component, but having low dimensional stability and not related to transparency It is recorded without special attention.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3939326

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-131826

[Patent Document 3] Japanese Patent Laid-Open No. Hei 11-43855

The present invention has been made in view of the above problems of the prior art, and provides a polyester long-fiber nonwoven fabric excellent in transparency, dimensional stability, powder leakage property, and component extractability, and a food filter using the same.

The inventors of the present invention have diligently studied and repeated experiments in order to solve the above problems, and as a result, have found that a polyester resin having a specific content of a titanium element is selected, and the structure, fiber diameter, and unit area of the fiber constituting the nonwoven fabric are selected. In view of the weight and the hot-pressed area ratio, a non-woven fabric which is excellent in spinnability and which is excellent in component extractability as a food filter and which is excellent in both transparency and dimensional stability is obtained. Further, the evaluation of the pore diameter calculated by directly observing the nonwoven fabric was defined as the powder leakage property, and the present invention was completed.

That is, the present invention is as follows.

[1] A single-layer or multi-layer polyester long-fiber non-woven fabric, wherein the content of inorganic particles is 0 to 100 ppm, the pore diameter of 10% is less than 1000 μm, and the difference between the pore diameter of 10% and the pore diameter of 2.3% is 500 or less, and The weight per unit area is 10~30g/m ² .

[2] The single-layer or multi-layer polyester long-fiber non-woven fabric according to the above [1], which has a thermocompression bonding area ratio of 5 to 40% and an average apparent density of 0.1 to 0.5 g/cm ³ .

[3] The single-layer or multi-layer polyester long-fiber nonwoven fabric of the above [1] or [2], which has an average fiber diameter of 13 to 40 μm.

[4] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of the above [1] to [3], wherein at least one layer is contained in the vicinity of 1740 cm ^-1 observed in the Raman spectrum by C = The average value of the full width at half maximum of the peak width generated by the O group is 18 to 24 cm ^-1 .

[5] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [4] above, wherein at least one layer contains fibers having a crystallinity of 30 to 50%.

[6] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of the above [1] to [5], wherein at least one layer contains fibers having a birefringence of 0.04 to 0.12.

[7] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of the above [1] to [6], which has a transparency of 60% or more.

[8] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of the above [1] to [7], which has a boiling water shrinkage ratio of 2.0% or less.

[9] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of the above [1] to [8], which has a texture coefficient of 0.5 to 2.0.

[10] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [9] above, wherein at least one of the layers has a tensile strength of 5 N/30 mm or more.

[11] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [10] above, wherein at least one layer contains a low melting point fiber having a melting point of 240 ° C or less.

[12] The polyester long-fiber nonwoven fabric according to any one of [1] to [11] above which comprises a laminated non-woven fabric in which the following a layer and b layer are integrated by thermocompression bonding.

a layer: polyester long fiber non-woven fabric containing a low melting point resin having a melting point difference of 30 ° C to 150 ° C with a high melting point resin

Layer b: polyester long-fiber non-woven fabric containing the above high melting point resin

[13] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of the above [1] to [12], The fiber having the above-mentioned polyester long fiber nonwoven fabric has a structure in which the orientation is different in the cross-sectional direction.

[14] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [13] above, wherein at least one layer contains a resin containing 0 to 25% of phthalic acid.

[15] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [14] wherein the inorganic particles are titanium oxide.

[16] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to [15] above, which comprises a resin having a titanium element content of 0 to 0.1 ppm.

[17] The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [16] above, wherein the resin having a non-woven fabric has an IV value of 0.6 or more.

[18] A filter for a food comprising the single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of [1] to [17] above.

The fiber constituting the single-layer or multi-layer polyester long-fiber nonwoven fabric of the present invention is excellent in spinnability, and the food filter produced by using the nonwoven fabric containing the fiber is excellent in component extractability, transparency, dimensional stability, and further resistance. Powder leakage is also good.

Fig. 1 is a schematic view showing an example of a device for controlling a gas flow such as a plate-shaped dispersion plate.

Fig. 2 is a graph showing the relationship between boiling water shrinkage ratio and transparency.

Fig. 3 is a graph showing the relationship between the draw ratio and the alignment crystallinity.

Fig. 4 is a graph showing the relationship between the spinning temperature and the alignment crystallinity.

Fig. 5 is a graph showing the relationship between the resin IV value and the alignment crystallinity.

Hereinafter, embodiments of the present invention will be described in detail.

Examples of the polyester-based resin constituting the polyester long fibers constituting the polyester long-fiber nonwoven fabric of the present embodiment include polyethylene terephthalate and polyparaphenylene as thermoplastic polyesters. As a representative example, butylene dicarboxylate or polytrimethylene terephthalate may be a polyester obtained by polymerizing or copolymerizing phthalic acid or phthalic acid as an acid component forming an ester. The thermoplastic polyester may further be a biodegradable resin such as a polyglycolic acid or a polylactic acid-like poly(α-hydroxy acid), or a copolymer of these as a main repeating unit element. These resins may be used singly or in combination of two or more.

The polyester long-fiber nonwoven fabric of the present embodiment has a higher transparency (lower concealability), and therefore, the content of the inorganic-based particles which are generally used as a matting agent in the thermoplastic synthetic fiber nonwoven fabric is preferably as low as possible.

As the inorganic particles used as the matting agent, any of a synthetic product and a natural product can be used without particular limitation. Examples of the inorganic particles include oxide ceramics such as alumina, cerium oxide, titanium oxide, zirconium oxide, magnesium oxide, cerium oxide, cerium oxide, zinc oxide, and iron oxide; tantalum nitride, titanium nitride, and nitriding; Nitride ceramics such as boron; tantalum carbide, calcium carbonate, aluminum sulfate, aluminum hydroxide, magnesium hydroxide, potassium titanate, talc, kaolin clay, kaolinite, dickite, diaphoric olivine-free vermiculite, multi-water Kaolin, pyrophyllite, glazed porphyry, montmorillonite, aluminum bentonite, nontronite, chrome ore, saponite, zinc bentonite, hectorite, vermiculite, iron-aluminum serpentine, sericite, Magnesia chlorite, manganese-aluminum serpentine, zinc-aluminum serpentine, nickel-aluminum serpentine, bentonite, zeolite, biotite, phlogopite, iron mica, magnesium-rich biotite, conifer mica, mica, scale mica, rich scale Mica, muscovite, chlorite rich magnesium biotite, iron green scale stone, iron aluminum green scale stone, calcium citrate, magnesium silicate, diatomaceous earth and strontium sand ceramics and glass fiber. These inorganic particles are used singly or in combination of two or more. From the viewpoint of the reactivity of the resin, the inorganic particles to be used are preferably inert inorganic particles such as titanium oxide, magnesium stearate or calcium stearate.

The preferred particle diameter of the inorganic particles constituting the polyester-based resin of the polyester long fiber of the present embodiment is 1.0 μm or less, preferably 0.8 μm or less, and more preferably 0.7 μm or less. When the particle diameter exceeds 1.0 μm, as a non-woven fabric, not only the transparency is lowered, but also the stability of spinning is deteriorated, so that the disadvantage of spinning such as breakage is also increased.

In the polyester resin constituting the polyester long fiber of the present embodiment, the content of the inorganic particles is preferably from 0 to 100 ppm, preferably from 0 to 50 ppm, more preferably from 0 to 0.1 ppm. By setting the content of the inorganic particles in the fibers within the above range, the transparency of the nonwoven fabric can be sufficiently ensured. In the case where the inorganic particles are used as the catalyst, the decomposition reaction of the resin during melt extrusion is suppressed, and the disadvantage of spinning such as breakage can be suppressed.

The inorganic particles used as the matting agent in the polyester-based resin constituting the polyester long fiber of the present embodiment are preferably inexpensive and generally used, and titanium oxide or the like which deactivates the reaction activity is preferably used. Titanium particles. In the case where a titanium element is used as the inorganic particles in the polyester resin constituting the polyester long fiber of the present embodiment, the content is preferably 0 to 100 ppm, preferably 0 to 50 ppm, more preferably 0 to 0.1 ppm. .

Specifically, it is preferably a colorless and transparent super bright resin to which inorganic inert particles such as titanium dioxide used as a matting agent are not added, and further preferably a resin which does not use a titanium compound as a catalyst. By not using a titanium compound as a catalyst, the decomposition reaction of the resin at the time of melt extrusion is suppressed, and the disadvantage of spinning such as breakage can be suppressed.

The leakage property of the inner bag when the polyester long fiber nonwoven fabric of the present embodiment is used as a packaging material can be defined by the distribution of the pore diameter.

The representative value of the aperture can be expressed as an aperture of 10% of the area ratio when the area of each hole in the non-woven image is sequentially accumulated from the largest area to the smaller area, and must be 1000 μm or less. A preferred range is 30 μm or more and 6000 μm or less, more preferably 400 μm or less, further preferably 300 μm or less, and most preferably 250 μm or less. If it is more than this range, the seam of the fabric becomes thin, and the powder leakage of the inner bag cannot be suppressed. On the other hand, if it is below this range, the seam of the fabric becomes fine, and the transparency of the filter is lowered. Further, since the filter suppresses the increase in the fluid resistance, when the filter is used as a food filter, the extraction time is increased and it is not practical.

The difference between the larger diameter pore size distribution from the maximum pore size of 2.3% and 10% points must It must be 0 μm or more and 500 μm or less. A preferred range is 300 μm or less, more preferably 200 μm or less, and still more preferably 150 μm or less. In the case of a fabric having a large pore size distribution of the non-woven fabric, by setting the frequency of the hole having a large diameter to be within this range, a nonwoven fabric excellent in powder leakage property can be obtained. Further, by combining with the above range of 10% pore diameter, the optimum pore size distribution for packaging tea leaves can be defined.

Further, in the case of a hole having the same hole area, as for the shape, it is preferable to have a longer diameter and a shorter diameter as an ellipse than a true circle. In the case of packaging contents such as tea leaves, since it is not a true ball with a smooth surface, even if it is the same hole area, when there is a hole having a long diameter and a short diameter, the tea leaves are stuck around the hole. leakage. The effect on the leakage of tea leaves and the like is particularly large in the shape of the relatively large pores contained in the nonwoven fabric. The shape of the pores can be expressed as a value obtained by dividing the average of the major diameters of the pores of the pores of 2.3% to 10% by the average of the pore diameters of the pores of 2.3% and 10%. This value is preferably 1.3 or more. Generally, as long as the transparency of the resin is the same, if the transparency of the resin is suppressed while maintaining the transparency, the resin will have a trade-off relationship, and the surface area of the fiber contained in the transparent fixing area, that is, the finer the fiber diameter and the weight per unit area. The larger and worse, the leakage of the contents is reduced. One method of suppressing the leakage of the contents while ensuring transparency in accordance with this relationship is to reduce the large pore diameter of the nonwoven fabric, and the other method is to make the shape of the pores into a shape in which the contents are less likely to leak. By simultaneously using the two methods, a non-woven fabric that further satisfies both the transparency and the leakage inhibition of the contents can be obtained.

The shape of the polyester long fiber of the present embodiment may be any fiber cross-sectional shape such as a hollow cross section, a core-sheath type composite cross section, a split type composite cross section, or a flat cross section, in addition to the usual circular cross section.

The polyester long-fiber nonwoven fabric of the present embodiment is used for forming a bag shape such as a tea bag, and is preferably high in strength in heat sealing processing by a bag making machine. In order to obtain a heat sealability with good adhesion strength, a fiber comprising a low melting point resin having a melting point of 240 ° C or less is laminated on at least one side of the polyester long fiber nonwoven fabric, and a difference in melting point is set, thereby being thermally dense. At the time of sealing processing, only the low-melting-point resin component softens or melts and functions as an adhesive, so that high heat-sealing strength can be effectively obtained.

The melting point of the above low melting point resin is higher than the melting point of the melting point resin by 30 to 150 ° C, preferably 30 to 100 ° C lower. Examples of the low melting point resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid, and ethylene glycol, diethylene glycol, and 1,4-butane. A copolymerized polyester resin obtained by polymerizing a glycol such as an alcohol or cyclohexane dimethanol or an aliphatic polyester resin such as polylactic acid. Further, the fiber structure is preferably a composite fiber structure including two components such as a sheath core structure or a side-by-side structure, in addition to a single component, for example, a core having a high melting point and a sheath having a low melting point composite fiber structure, specifically, a core It is a high melting point resin such as polyethylene terephthalate or polybutylene terephthalate, and the sheath is a low melting point resin such as a copolymerized polyester or an aliphatic polyester. The method of laminating the low-melting-point fibers may be, for example, a method in which the resin is melted, and a semi-molten resin or a fibrous material thereof is applied to a curtain spray method of a non-woven fabric, and the melted resin is ejected from the nozzle. A method of applying a non-woven fabric, or a method of laminating a high-melting-point fiber web and a low-melting-point fiber web, and joining them by a heat roll or the like to obtain a laminated non-woven fabric.

For example, when a low-melting-point resin contains a terephthalic acid-based aromatic dicarboxylic acid as a component, a second aromatic dicarboxylic acid such as isophthalic acid, phthalic acid or naphthalene dicarboxylic acid can be copolymerized. After use. The amount of the second aromatic dicarboxylic acid at this time is 0 to 25%, preferably 0 to 22%, more preferably 0 to 18%, based on the total amount of the aromatic dicarboxylic acid. When the amount exceeds this range, the crystallinity is lowered, and the molecular orientation formed by the stretching does not occur, so that the spinning stability or the mechanical strength or dimensional stability when the nonwoven fabric is formed is lowered.

The polyester long fiber nonwoven fabric of the present embodiment is preferably ultrasonically fusible or heat-sealed. The sealing strength is preferably 0.1 N/30 mm or more, more preferably 0.2 N/30 mm or more. The heat sealing condition can be appropriately selected. For example, the temperature condition of the heat sealing is preferably 5 to 80 ° C lower than the melting point of the resin of the sealing surface.

Furthermore, other common additions can be added without hindering the desired effect. Ingredients such as impact modifiers such as various elastomers, crystal nucleating agents, coloring inhibitors, antioxidants, heat stabilizers, plasticizers, lubricants, weathering agents, antibacterial agents, colorants, pigments, dyes, etc. .

The polyester long fiber nonwoven fabric of the present embodiment can be efficiently produced by a spunbonding method. In other words, the polyester resin is heated and melted and ejected from the spinneret, and the obtained spun yarn is cooled by a known cooling device, and is drawn and refined by a suction device such as an air suction plate (Air Sucker). Then, after the filament group discharged from the suction device is opened, it is deposited on a conveyor belt to form a net. Then, a portion of the web formed on the conveyor belt is thermocompression bonded using a local thermocompression bonding apparatus such as a heated embossing roll, thereby obtaining a long-fiber spunbonded nonwoven fabric.

In the case of using the spunbonding method, there is no particular limitation, and in order to improve the uniformity of the web, for example, a method of charging a fiber by a corona device or the like as disclosed in Japanese Patent Laid-Open No. Hei 11-131355, or a flat plate is used. The device for controlling the air flow such as the dispersing plate (refer to FIG. 1) adjusts the velocity distribution of the airflow in the ejecting portion of the ejector, and after the fiber is opened, the mesh is blown, and the scattering of the net is suppressed, and the area of the capturing surface is borrowed. This becomes a further preferred method.

The non-woven fabric obtained by the spunbonding method has characteristics of physical properties such as strong cloth strength and absence of breakage of short fibers caused by breakage of the joint portion, and low cost and high productivity, so that it is used for hygiene, A wide range of uses centered on civil engineering, construction, agriculture/horticulture, and living materials.

The polyester long fibers of the present embodiment have a fiber diameter of 13 to 40 μm, preferably 15 to 40 μm, more preferably 18 to 35 μm, and particularly preferably 21 to 30 μm. When the fiber diameter is 13 μm or more, the transparency can be designed to be sufficient. Further, if the fiber is insufficiently resistant to the tension of the ejector during spinning, and the fiber having a small portion of the fiber is broken, the fiber diameter is 40 μm or less, and when it is made into a non-woven fabric and used as a filter for food, mechanical strength or It is excellent in rigidity, component extraction property, transparency, and sealing property, and is suitable as a food filter.

The surface area per unit area of the polyester long fiber nonwoven fabric of the present embodiment (that is, the specific surface area m ² /g × unit area weight g/m ^{2 of the} long fiber nonwoven fabric) is 1.0 to 3.5 (m ² /m ² ), more preferably It is 1.2 to 3.0 (m ² /m ² ), and particularly preferably in the range of 1.3 to 2.7 (m ² /m ² ). When the surface area per unit area is 3.5 (m ² /m ² ) or less, the transparency can be designed to be sufficient. In addition, when the surface area per unit area is 1.0 or more, a sufficient number of fibers can be obtained when the nonwoven fabric is formed. Therefore, when used as a food filter, it is excellent in mechanical strength, rigidity, component extraction property, and sealing property. Suitable as a food filter.

The layer structure of the polyester long fiber nonwoven fabric of the present embodiment is not particularly limited as long as it is a nonwoven fabric by thermal/chemical integration, and may be a laminated nonwoven fabric. In this case, it is preferable to form a layer which distinguishes the roles assumed by the respective layers. For example, the first layer is a layer having a high heat-sealing strength, and the other layer is a layer having excellent mechanical strength such as tensile strength, rigidity, dimensional stability, etc., whereby a seal required for bag making can be obtained. Non-woven fabric with excellent properties and excellent mechanical properties. Further, in the step of forming the non-woven fabric into a bag shape, if a non-woven fabric having a structure of only one layer and having both mechanical strength and sealing properties is used, the step of producing the bag by heat subsequent processing is high. The heating and pressure bonding treatment is carried out, so that the thermoplastic resin is melted and adhered to the heat roller or the hot plate heater of the bag making apparatus, resulting in a decrease in the quality of the product or a decrease in the processing speed. If this condition is to be improved, the desired sealing strength cannot be obtained. . On the other hand, in the nonwoven fabric of the present embodiment, by providing the sealing layer on the inner surface, it is possible to exhibit good sealing strength and to produce without lowering the quality and production speed.

In the case where a laminated nonwoven fabric is used as the polyester long-fiber nonwoven fabric of the present embodiment, the structure of the layer which is responsible for the sealing property may be a single fiber structure or a sheath core structure or a side-by-side structure or a split-cut structure such as a spunbonding method or a melt-blown method. The fiber or the like has a composite fiber structure of two components, and preferably has a structure in which a low melting point resin which is capable of sealing properties is disposed on the surface of the fiber. For example, the core fiber has a high melting point and the sheath has a low melting point composite fiber structure. Specifically, the core is a high melting point resin such as polyethylene terephthalate or polybutylene terephthalate, and the sheath is copolymerized. Ester or fat A non-woven fabric of a sheath core structure composed of the above-mentioned low-melting resin such as a fatty polyester.

In the case where the laminated nonwoven fabric is used as the polyester long-fiber nonwoven fabric of the present embodiment, the method for producing the layer of mechanical strength is not particularly limited, and from the viewpoint of productivity and the like, a spunbonding method is preferred.

In particular, when a laminated nonwoven fabric is used as the polyester long-fiber nonwoven fabric of the present embodiment, the production method and physical properties of the layer for mechanical strength can be produced by the above method, and dimensional stability and mechanical strength can be obtained. Excellent non-woven fabric.

In the case where the laminated nonwoven fabric is used as the polyester long-fiber nonwoven fabric of the present embodiment, the pressure-bonding method is not particularly limited as long as the fibers can be integrated with each other, and it is preferable to laminate the layers. Thereafter, it is subjected to thermocompression bonding using a heat roller or the like to form a nonwoven fabric. By thermocompression bonding after laminating the layers, the strength between the layers can be made stronger, and the mechanical strength or sealing performance can be more effectively exhibited.

By forming the layer structure of the laminated non-woven fabric in the present embodiment as a laminated structure as described above, the sealing strength can be further improved. The specific sealing strength is 1.5 N/30 mm or more, preferably 2.0 N/30 mm or more, and more preferably 2.5 N/30 mm or more.

Further, the mechanical strength, that is, the tensile strength may be further preferably in the range of 15 N/30 mm or more, preferably 20 N/30 mm or more, and more preferably 23 N/30 mm or more.

The thermocompression bonding of the polyester long-fiber nonwoven fabric of the present embodiment is not particularly limited as long as it is a method of pressure-bonding the nonwoven fabric yarn to the yarn by heat, and the nonwoven fabric can be passed through a surface structure including irregularities. It is preferable that one of the embossing roll and the smooth roll is formed between the heating rolls to form a thermocompression-bonding portion which is uniformly dispersed throughout the nonwoven fabric. In the case of thermocompression bonding using an embossing roll, it is preferable to carry out thermocompression bonding at a thermocompression bonding area ratio of 5 to 40% with respect to the total area of the non-woven fabric, and more preferably 7 to 30%. Further preferably, it is 7 to 20%.

If the thermocompression bonding area ratio is within this range, good thermal compression bonding treatment of the fibers can be performed to achieve moderate mechanical strength or rigidity, transparency, component extractability, dimensional stability of the obtained non-woven fabric. The aspect is better. The temperature and pressure of the thermocompression bonding treatment should be appropriately selected according to the basis weight and speed of the supplied network, and it is not intended to be general. It is preferably a temperature lower than the melting point of the polyester resin by 10 to 90 ° C, more preferably lower. Temperature of 20~60 °C.

In the thermocompression bonding step, in addition to the embossing roll, a wind blowing method in which the hot air is passed through the net to press the wire with the wire by heat may be used. In the case of thermocompression bonding by the wind blowing method, since the surface of the fabric does not have local irregularities such as embossed shapes, the non-woven fabric can be made more transparent.

The boiling water shrinkage ratio of the polyester long-fiber nonwoven fabric of the present embodiment is preferably 2.0% or less, more preferably 1.6% or less, further preferably 1.0%, and particularly preferably 0.5% or less. When the boiling water shrinkage ratio is 2.0% or less, there is almost no shrinkage in the thermoforming process or the like, and the step stability is excellent, and even in the form of use such as exposure to a high temperature environment close to 100 ° C, the form retention property is also Excellent. The lower limit is preferably 0%, and is actually 0.2% or more.

The transparency of the polyester long-fiber nonwoven fabric of the present embodiment is preferably 60% or more, more preferably 65% or more, still more preferably 70% or more. If the transparency is less than 60%, it is difficult to see the state of the contents through the nonwoven fabric and it becomes unclear.

The polyester long-fiber nonwoven fabric of the present embodiment has a basis weight of 10 to 30 g/m ² , preferably 12 to 25 g/m ² . When the basis weight is 10 g/m ² or more, the transparency and the component extractability can be maintained, and the mechanical strength can be sufficiently ensured. On the other hand, when the basis weight is 30 g/m ² or less, transparency and component extractability can be obtained.

The thickness of the polyester long fiber nonwoven fabric of the present embodiment is preferably 0.02 to 0.50 mm, more preferably 0.03 to 0.30 mm. When the weight per unit area and the thickness are within this range, transparency, mechanical strength, and component extractability which are excellent when used as a food filter can be obtained.

The average apparent density of the polyester long-fiber nonwoven fabric of the present embodiment is preferably from 0.10 to 0.50 g/cm ³ , more preferably from 0.12 to 0.30 g/cm ³ . The average apparent density is related to the rigidity, transparency, powder leakage property, and component extraction property of the nonwoven fabric. When the ratio is within the above range, the fiber gap is moderate, and thus it is suitable as a food filter. When the average apparent density is 0.10 g/cm ³ or more, the fiber gap can be adjusted to appropriately suppress the amount of powder leakage, and the mechanical strength can be made sufficient. On the other hand, when the average apparent density is 0.50 g/cm ³ or less, the fiber gap is not excessively small, and the component extractability can be appropriately maintained, and the product quality can be made sufficient.

The tensile strength in the MD (Machine Direction) direction of the polyester long fiber nonwoven fabric of the present embodiment is preferably 5 to 40 N/30 mm, more preferably 6 to 40 N/30 mm, still more preferably 7 to 40 N/30 mm. When the tensile strength is at least the above range, it is excellent in production stability at the time of bag making processing, damage prevention when used as a filter for foods, and the like.

The texture coefficient of the polyester long fiber nonwoven fabric of the present embodiment is preferably from 0.5 to 2.0, more preferably from 0.5 to 1.5. The texture coefficient indicates the uniformity of the non-woven fabric, and thus is related to strength, rigidity, transparency, powder leakage, and component extractability. When it is in the above range, the uniformity of the non-woven fabric is optimal, and therefore it is excellent in the strength, rigidity, transparency, suitability for processing into a bag shape, and powder leakage property as a food filter.

The spinning temperature at which the polyester long fibers of the present embodiment are obtained is preferably a temperature higher by 10 to 60 ° C than the melting point of the polyester resin, more preferably 10 to 30 ° C higher. When the spinning temperature is in this range, the monofilament breakage or the like does not occur, and the alignment crystallinity is moderate, and a nonwoven fabric excellent in mechanical strength or dimensional stability can be obtained.

The inherent viscosity (IV value) of the resin after the polyester long-fiber nonwoven fabric of the present embodiment is made into a non-woven fabric is preferably 0.6 or more, more preferably 0.65 or more, still more preferably 0.7 or more. When the resin pellets are melt-extruded, the resin is decomposed due to heat load during melting or shear load during kneading. When the IV value of the resin after the non-woven fabric is melted, the IV value of the resin is more than or equal to the above range, the decomposition of the resin can be preferably suppressed, and the elongation and crystallization of the resin during spinning can be promoted, so that mechanical strength can be obtained. Non-woven fabric with excellent dimensional stability.

The spinning speed at which the polyester long fibers of the present embodiment are obtained is preferably from 3,000 to 6,000 m/min, more preferably from 3,500 to 5,000 m/min. When the pulling speed in the drawing refining of the spun yarn is within the above range, the alignment crystallization of the polyester long fibers is sufficient, and a non-woven fabric excellent in mechanical properties or dimensional stability can be obtained, and breakage occurs in the spinning. There are fewer possibilities and it is better in terms of the productivity of non-woven fabrics.

The stretching of the polyester long fiber of the present embodiment is preferably from 400 to 2,500, more preferably from 700 to 2,200. When the draw ratio in the case of drawing and refining the spun yarn is within the above range, the alignment crystallization of the polyester long fibers is sufficient, and a non-woven fabric excellent in mechanical properties or dimensional stability can be obtained, and breakage occurs in the spinning. Or the possibility of "winding on the roll" at the time of thermocompression bonding is low, and therefore it is also preferable in terms of the productivity of the non-woven fabric.

The birefringence Δn of the polyester long fibers of the present embodiment is from 0.04 to 0.12, preferably from 0.06 to 0.1. When the birefringence is in this range, the orientation of the fibers is moderate, and a nonwoven fabric excellent in mechanical strength or dimensional stability can be obtained.

The method for evaluating the crystallinity is not particularly limited, and for example, it can be measured by a crystallinity measurement by DSC (Differential Scanning Calorimetry) or a Raman spectrometry.

The polyester long fiber of the present embodiment has a crystallinity of 30 to 50%, preferably 40 to 50%. When the degree of crystallinity is within this range, fibers excellent in mechanical strength or dimensional stability can be obtained.

When the crystallinity of the polyester long fiber of the present embodiment is carried out by Raman spectroscopy, the peak of the C=O group in the vicinity of 1740 cm ^-1 observed in the Raman spectrum of the fiber profile can be utilized. The average of the full amplitude of the half-width of the width was evaluated. The average value of the full width at half maximum of the peak width is 18 to 24 cm ^-1 , preferably 19 to 24 cm ^-1 , and more preferably 20 to 23 cm ^-1 . If the average value of the full width at half maximum of the peak width is within this range, fibers excellent in mechanical strength or dimensional stability can be obtained.

The polyester long fiber of the present embodiment can crystallize differently in the radial direction of the fiber. For example, the crystallinity of the outer peripheral portion is high, and the internal crystallinity is low. By making the crystallinity of the outer peripheral portion high, it is possible to produce a fiber which is less likely to shrink and has excellent mechanical strength, and by making the internal crystallinity low, the crimp strength of the fibers can be sufficiently obtained at the time of thermocompression bonding. As a result, it is possible to produce a non-woven fabric excellent in mechanical strength or dimensional stability. This case can be confirmed by evaluating the melting peak when the crystallinity is measured by DSC.

Fig. 2 shows the relationship between the boiling water shrinkage ratio and the transparency of the polyester long-fiber nonwoven fabric in the examples of the present invention. When the fiber diameter is increased, the transparency can be increased, but the alignment crystallization is less likely to occur, so that the boiling water shrinkage ratio is increased and the dimensional stability is lowered.

The relationship between the draw ratio and the spinning temperature of the polyester long-fiber nonwoven fabric in the examples of the present invention and the alignment crystallinity represented by the birefringence (?n) and the crystallinity are shown in Figs. 3 and 4, respectively. The more the draw ratio is increased, the more the alignment crystallinity of the fiber increases. Further, under the spinning conditions of the coarse fiber diameter, the spinning temperature is lowered, and the cooling property is increased, whereby the elongation efficiency is increased, and the alignment crystallization of the fibers can be performed.

Fig. 5 shows the relationship between the intrinsic viscosity (IV value) of the resin of the polyester long-fiber nonwoven fabric in the embodiment of the present invention and the alignment crystallinity expressed by the birefringence (?n) and crystallinity. By increasing the IV value of the resin, the alignment crystallization of the resin can be promoted, and the alignment crystallization of the fibers can be performed.

In the light of the above, the inventors of the present invention have used the low temperature of the spinning temperature and the expansion ratio to maintain the coarse fiber diameter and improve the alignment crystallization. Sex, thereby achieving improved transparency and boiling water shrinkage. That is, the improvement of the transparency in the nonwoven fabric is inversely related to the improvement of the dimensional stability represented by the boiling water shrinkage ratio, but the inventors of the present invention have made the fiber coarse fiber diameter and the alignment crystallinity into an optimum range. At the same time, it achieves improved transparency and dimensional stability.

Further, by optimizing the intrinsic viscosity (IV value) of the resin used in the present invention, the optimum range of the alignment crystallization can be achieved. The range of IV values used to achieve this purpose is 0.7 The above is preferably 0.85 or less, and more preferably in the range of 0.72 to 0.8. When the intrinsic viscosity is in this range, the monofilament breakage or the like is not generated, and stable productivity can be ensured, and higher alignment crystallinity can be obtained when the molten resin is subjected to drawing refinement, whereby a higher degree can be obtained. Dimensional stability and mechanical strength.

The polyester long-fiber nonwoven fabric of the present embodiment is preferably excellent in hydrophilicity, so that it does not float to the surface when it is placed in hot water but sinks quickly. The hydrophilic agent is preferably used as a surfactant for foods, for example, an aqueous solution such as sorbitan fatty acid ester, polyglycerin fatty acid ester or sucrose fatty acid ester, an ethanol solution, or a mixed solution of ethanol and water. The coating method can be applied to a known method such as a gravure roll method, a contact roll method, a dipping method, or a spray method.

The polyester long-fiber non-woven fabric of the present embodiment may be subjected to conventional post-processing, such as a deodorant, an antibacterial agent, etc., and may be subjected to dyeing, water-repellent processing, and water-permeable processing, without damaging the effects required by the present invention. Wait.

Since the polyester long-fiber nonwoven fabric of the present embodiment is excellent in transparency, the content can be clearly seen, and therefore, it is excellent in design and excellent in dimensional stability, and therefore is suitable as a food filter for green tea, black tea, coffee, and the like. Characteristics. The food filter may be a flat bag. However, if it is a three-dimensional shape, the content can be more clearly seen and extracted efficiently, which is preferable. The three-dimensional shape is preferably a tetrahedral shape, a triangular pyramid three-dimensional shape or the like.

The three-dimensional shape food filter is sold by being filled and sealed in an extract, and then sold in a bag, but it is required to quickly return to the original three-dimensional shape when the consumer who has purchased it is taken out from the bag. The long-fiber non-woven fabric of the present invention has elasticity and thus has moderate rigidity, so that the above-mentioned requirements can be sufficiently satisfied.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Further, the measurement methods, evaluation methods, and the like used are as follows.

(1) Titanium content (ppm)

The content of titanium element in the polyester resin was determined using an ICP (Inductively Coupled Plasma) luminescence analyzer manufactured by Thermo Fisher Scientific.

(2) Average fiber diameter (μm)

The diameter of the fiber was magnified 1000 times using a Microscope microscope (VH-8000) manufactured by KEYENCE, and the average fiber diameter was determined from the average of 20 pieces.

(3) Birefringence (Δn)

The pressure was compensated using a BH2 type polarizing microscope manufactured by OLYMPUS, and the birefringence of the fiber immediately after drawing was determined by the usual interference fringe method and based on the retardation and the fiber diameter.

(4) Crystallinity (%)

Using a differential scanning calorimeter DSC6000 manufactured by PerkinElmer Co., Ltd., the temperature was raised from 40 ° C to 300 ° C at a temperature increase rate of 10 ° C / min, and the crystallization heat generation amount ΔHc and the crystal melting heat amount ΔHm were measured. The degree of crystallinity (%) was determined according to the following formula: crystallinity χc (%) = (ΔHm - ΔHc) / 126.4 × 100

*126.4 J/g is the heat of fusion of the complete crystallization of polyethylene terephthalate.

(5) Half-peak full amplitude (cm ^-1 )

The spectrum was measured using a micro-Raman spectroscopic device manufactured by Renishaw Co., Ltd. with excitation light of 532 nm and excitation light intensity of 10%. The full width at half maximum of the peak width generated by the C=O group in the vicinity of 1740 cm ^-1 observed in the spectrum was determined.

(6) Intrinsic viscosity (IV value)

The measurement was carried out in accordance with JIS K-7367-5.

(7) Unit weight (g/m ² )

The measurement was carried out in accordance with JIS L-1906.

(8) Thickness (mm)

The thickness of the load of 100 g/cm ^{2 was} measured by the method specified in JIS L-1906.

(9) Average apparent density (g/cm ³ )

The mass per unit volume was determined according to the basis weight and thickness measured by the method specified in JIS L-1906: average apparent density (g/cm ³ ) = (unit weight g/m ² ) / ((thickness mm) )×1000)

(10) Thermocompression bonding area ratio (%)

A 1 cm square test piece was sampled, and a photograph was taken by an electron microscope, and the area of the thermocompression bonded portion was measured based on the respective photographs, and the average value thereof was defined as the area of the thermocompression bonded portion. Further, the distance between the patterns of the thermocompression bonding portions is measured in the MD direction and the CD (Cross Direction) direction, and the ratio of the thermocompression bonding area to the area per unit area of the non-woven fabric is calculated as the thermocompression bonding area ratio based on the values. .

(11) Transparency (%)

The reflectance (L value) was measured using a Macbeth spectrophotometer (CE-7000A type: manufactured by Sakata Inx Co., Ltd.), and the difference between the L value (L _w0 ) of the standard whiteboard and the L value (L _b0 ) of the standard blackboard was obtained as The basis is based on the L value (L _w ) on which the sample is placed on the whiteboard and the L value (L _b ) placed on the blackboard in the same manner and the transparency is obtained according to the following formula: transparency (%) = {(L) _w -L _b )/(L _w0 -L _b0 )}×100

(12) boiling water shrinkage rate (%)

According to JIS L-1906, three test pieces of 25 cm in length and 25 cm in width were taken on a sample having a width of 1 m, which was immersed in boiling water for 3 minutes, and the shrinkage ratio in the MD direction and the CD direction was determined after natural drying. . The average value of each was calculated, and the shrinkage ratio of the larger one of the MD direction and the CD direction was taken as the boiling water shrinkage ratio of the nonwoven fabric.

(13) Tensile strength (N/30mm)

Using an automatic stereographer AGS-5G model manufactured by Shimadzu Corporation, the specimen of 30 mm width was stretched with a grip length of 100 mm and a tensile speed of 300 mm/min, and the obtained load at break was used as the strength, and the non-woven fabric was used. Five measurements in the MD direction The average value.

(14) Texture coefficient

A test piece of 20 cm × 30 cm was used, and a transmission image obtained by photographing a range of 18 cm × 25 cm by a CCD (Charge Coupled Device) camera was decomposed into a measurement tester (FMT-MIII) measuring instrument manufactured by Nomura Corporation. A pixel of 128 × 128 is measured for the intensity of light received by each pixel, and the transmittance is calculated. The texture coefficient is a value obtained by dividing the standard deviation (σ) of the transmittance of each minute portion (5 mm × 5 mm) of the sample by the average transmittance (E), and indicates the deviation of the weight per unit area. The smaller the value, the smaller the value. The higher the uniformity.

Texture coefficient = σ / E × 100

(15) Heat sealing strength (N/30mm)

Using the auto-stereograph AGS-5G model manufactured by Shimadzu Corporation, the heat-sealed portion of the 30 mm-wide specimen was peeled off by about 50 mm in the up-and-down direction, and then mounted to hold the length of 50 mm and the tensile speed of 100 mm/min. The load at the time of the fracture obtained was taken as the strength, and the MD direction of the non-woven fabric was measured five times, and the average value was obtained. The heat sealing condition is a sealing temperature of 210 ° C, a sealing time of 1 second, a pressure of 0.5 MPa, and a sealing area of 7 mm × 25 mm.

(16) Stretch ratio

The draw ratio was calculated according to the following formula: draw ratio = spinning speed (m/min) / discharge line speed (m/min)

Ejection line speed (m/min) = single hole discharge amount (g/min) / {melt density (g/cm ³ ) × [spinning nozzle diameter (cm) / 2] ² × π}

* Melt density of polyester: 1.20g/cm ³

(17) Surface area per unit area of polyester long fiber nonwoven fabric

It was determined from the specific surface area m ² /g × unit area weight g/m ² of the long fiber nonwoven fabric.

The specific surface area (m ² /g) of the long-fiber nonwoven fabric was determined by using an automatic specific surface area measuring machine Gemini 2360 of Shimadzu Corporation. Moreover, when the specific surface area is less than 0.1 m ² /g, it is obtained by the following formula.

Surface area (m ² /m ² ) = 4 × weight per unit area (g/m ² ) / density of resin (g/cm ³ ) / fiber diameter (μm)

In the case of a sheet of two or more kinds of fiber diameters, the surface area of each fiber diameter is totaled.

(18) 10% aperture

Ten samples of 2 cm square were cut out from one sample, and platinum vapor deposition was performed by an ion sputtering apparatus using an SEM (scanning electron microscope), and the light was transmitted at 100 times magnification by using transmitted light. 10 non-woven images in the sample were taken. The image analysis software is used to binarize the non-woven portion into black, the hole portion is binarized to white, and the area and the longest path of all the holes in the image are quantized. The image analysis software system uses "A Like Jun (TM)" manufactured by Asahi Kasei Engineering. All the holes in one sample image are sequentially arranged from the largest area to the smaller area. According to the area of the hole reaching the point of 10% of the total hole area, the diameter of the circle equal to the area is used. The aperture is determined by the above equation.

Aperture (μm) = ((4 × S) / π) ^{^} 0.5

In the above formula, S means the pore area (μm ^{^} 2), and " ^{^} 0.5" means "multiplied by 0.5".

(19) 2.3% aperture

Instead of the above 10% pore diameter, the pore diameter was determined from the pore area at a point which reached 2.3% of the total pore area.

(20) Long diameter / aperture

All the holes in one sample image are sequentially arranged from the largest area to the smaller area, and the long diameter of all the holes included between the holes reaching 2.3% of the total hole area and the holes reaching 10% is determined. The average value and the average value of the pore diameters were obtained by the following formula.

Long diameter / aperture = average of long diameter / average of aperture

[Example 1]

A polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, and is spun from a spinning hole having a circular cross section. The head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 2120 to obtain a polyester long fiber having a fiber diameter of 20.5 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament is 4°], the fiber is opened and dispersed to produce a net having a basis weight of 12 g/m ² , and is applied to the embossing roll and the smooth roll. A partial thermocompression bonding was carried out at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 2]

In the same manner as in Example 1, a polyester long fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the fiber diameter of the polyester long fibers was 25.7 μm. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 3]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the fiber diameter of the polyester long fibers was 30.0 μm. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 4]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a resin having an IV value of 0.8 and a titanium oxide content of 12 ppm was used in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 5]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a resin having an IV value of 0.8 and a titanium oxide content of 70 ppm was used in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 6]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a resin having an IV value of 0.72 and a titanium oxide content of 0 ppm was used in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 7]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a resin having an IV value of 0.77 and a titanium oxide content of 0 ppm was used in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 8]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 3 except that the basis weight of the polyester long-fiber nonwoven fabric was 20 g/m ² in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 9]

In the same manner as in Example 1, except that the spinning was carried out at a spinning speed of 3,770 m/min and a draw ratio of 707, and the fiber diameter of the polyester long fibers was 34.9 μm. The way to obtain polyester long fiber non-woven fabric. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 10]

In the same manner as in Example 2, except that the basis weight of the polyester long-fiber nonwoven fabric was 20 g/m ² , and the entire surface was thermocompression bonded by a smooth roll. Polyester long fiber non-woven fabric. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 11]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 246 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4000 m/min and a draw ratio of 942 to obtain a polyester long fiber having a fiber diameter of 30.1 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament is 4°], the fiber is opened and dispersed to produce a net having a basis weight of 20 g/m ² , and is applied to the embossing roll and the smooth roll. A partial thermocompression bonding was carried out at a thermocompression bonding area ratio of 5%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 12]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 246 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4000 m/min and a draw ratio of 942 to obtain a polyester long fiber having a fiber diameter of 30.0 μm. Then, the fiber was opened and dispersed to prepare a web having a basis weight of 12 g/m ² , and a partial thermocompression bonding was performed between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, thereby obtaining a polyester long fiber. Not woven. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 13]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 246 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4000 m/min and a draw ratio of 942, and a flat-shaped dispersion device for controlling the gas flow [the inclination angle of the flat plate with respect to the filament was 4°] was used to make the fiber diameter 26.7 μm. The polyester long fibers were opened and dispersed to produce a net having a basis weight of 18 g/m ² . Then, a polyester resin having a titanium content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C was supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4150 m/min and a draw ratio of 412, and a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filament was 4°] was used to make the fiber diameter 15 μm. The polyester long fibers were opened and dispersed to produce a net having a basis weight of 3 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 14]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 246 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4000 m/min and a draw ratio of 942, and a flat-shaped dispersion device for controlling the gas flow [the inclination angle of the flat plate with respect to the filament was 4°] was used to make the fiber diameter 24.6 μm. The polyester long fibers were opened and dispersed to produce a net having a basis weight of 10 g/m ² . Then, a polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 12 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and a spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 895. The filament was expanded and dispersed using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filament was 4°] to produce a web having a basis weight of 8 g/m ² by disintegrating the polyester long fibers having a fiber diameter of 20 μm. A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 15]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the polyester long-fiber nonwoven fabric was 18 g/m ^{2 in} the first embodiment. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 16]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the polyester long-fiber nonwoven fabric was 18 g/m ^{2 in the second} embodiment. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 17]

A polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the polyester long-fiber nonwoven fabric was 18 g/m ² in Example 3. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 18]

In the first embodiment, the first layer nonwoven fabric was produced in such a manner that the basis weight of the polyester long fiber nonwoven fabric was 18 g/m ² . A PET (polyethylene terephthalate) resin having an IV value of 0.65, a titanium content of 0 ppm, and a melting point of 217 ° C was used thereon at a spinning temperature of 260 ° C and a heated air of 500 Nm ³ /hr/m. In the spinning, the obtained melt-blown nonwoven fabric having a fiber diameter of 10 μm was blown onto the spunbonded nonwoven fabric at a basis weight of 5 g/m ² to obtain a laminate of the nonwoven fabric. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Embodiment 19]

In Example 2, a first layer of nonwoven fabric was produced in such a manner that the basis weight of the polyester long fiber nonwoven fabric was 18 g/m ² . The PET resin having an IV value of 0.65, a titanium content of 0 ppm, and a melting point of 217 ° C was used for spinning at a spinning temperature of 255 ° C and a heated air of 400 Nm ³ /hr/m, and the obtained fiber having a diameter of 15 μm was melted. The non-woven fabric was blown onto the spunbonded nonwoven fabric at a basis weight of 4 g/m ² to obtain a laminate of non-woven fabric. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 20]

In Example 3, a first layer of nonwoven fabric was produced in such a manner that the basis weight of the polyester long-fiber nonwoven fabric was 18 g/m ² . The PET resin having an IV value of 0.65, a titanium content of 0 ppm, and a melting point of 217 ° C was used for spinning at a spinning temperature of 265 ° C and a heated air of 1000 Nm ³ /hr/m, and the obtained fiber having a diameter of 7 μm was melted. The non-woven fabric was blown onto the spunbonded nonwoven fabric at a basis weight of 4 g/m ² to obtain a laminate of non-woven fabric. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 21]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 230 to obtain a polyester long fiber having a fiber diameter of 14 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head of a spinning hole having a circular cross section was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 380. The filaments were spread using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filaments was 4°], and the polyester long fibers having a fiber diameter of 14 μm were opened to prepare a web having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 22]

A polyester resin having a titanium content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C was supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 590 to obtain a polyester long fiber having a fiber diameter of 20.1 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head of a spinning hole having a circular cross section was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 380. The filaments were spread using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filaments was 4°], and the polyester long fibers having a fiber diameter of 14 μm were opened to prepare a web having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 23]

A polyester resin having a titanium content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C was supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 740 to obtain a polyester long fiber having a fiber diameter of 24.6 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head of a spinning hole having a circular cross section was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 380. The filaments were spread using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filaments was 4°], and the polyester long fibers having a fiber diameter of 14 μm were opened to prepare a web having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 24]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, and is spun from a spinning hole having a circular cross section. The filament was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 550 to obtain a polyester long fiber having a fiber diameter of 20.1 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 10 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 450. The filaments were dispersed in a flat-shaped polyester fiber having a fiber diameter of 16 μm by using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°] to produce a net having a basis weight of 5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 25]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, and is spun from a spinning hole having a circular cross section. The filament was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 590 to obtain a polyester long fiber having a fiber diameter of 20.1 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 450. The filaments were dispersed in a flat-shaped polyester fiber having a fiber diameter of 16 μm by using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°] to produce a net having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 26]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, and is spun from a spinning hole having a circular cross section. The filament was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 740 to obtain a polyester long fiber having a fiber diameter of 24.6 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 450. The filaments were dispersed in a flat-shaped polyester fiber having a fiber diameter of 16 μm by using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°] to produce a net having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 27]

A polyester resin having a titanium content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C was supplied to a conventional melt spinning apparatus and melted at 275 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 590 to obtain a polyester long fiber having a fiber diameter of 20.1 μm. Then, the fiber was opened and dispersed using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament of 0°] to prepare a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 450. The filaments were opened and dispersed using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filaments by 0°] to produce a polyester long fiber having a fiber diameter of 16 μm to prepare a web having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 28]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 22 except that the inclination angle of the flat plate of the flat air flow control device was set to 0° with respect to the filament. The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 29]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 21 except that the layer of the low melting point resin was used as a side-by-side structure. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 30]

A polyester long fiber nonwoven fabric was obtained by the same method as in Example 24 except that the layer of the low melting point resin was used in a side-by-side structure. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 31]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 22 except that the layer of the low melting point resin was used as a side-by-side structure. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 32]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 21 except that the weight per unit area of each layer was 6 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 33]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 22 except that the weight per unit area of each layer was 6 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 34]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 23 except that the basis weight of each layer was 6 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 35]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C, and is spun from a spinning hole having a circular cross section. The filament was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 590 to obtain a polyester long fiber having a fiber diameter of 20.1 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 12 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head having a circular cross section of the spinning hole was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 450. The filaments were dispersed in a flat-shaped polyester fiber having a fiber diameter of 16 μm by using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°] to produce a net having a basis weight of 6 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 36]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 25 except that the basis weight of each layer was changed to 9 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 37]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 21 except that the weight per unit area of each layer was changed to 9 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 1 below.

[Example 38]

A polyester resin having a titanium content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C was supplied to a conventional melt spinning apparatus and melted at 305 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 230 to obtain a polyester long fiber having a fiber diameter of 10 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament was 4°], the fibers were opened and dispersed to produce a net having a basis weight of 7.5 g/m ² . Then, a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C was used as a core, and the titanium element content was 0 ppm, the intrinsic viscosity (IV) was 0.65, and the melting point was 217 ° C. The ester resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head of a spinning hole having a circular cross section was melt-spun at a spinning speed of 4500 m/min and a draw ratio of 380. The filaments were spread using a flat-shaped dispersing device for controlling the gas flow [the inclination angle of the flat plate with respect to the filaments was 4°], and the polyester long fibers having a fiber diameter of 14 μm were opened to prepare a web having a basis weight of 7.5 g/m ² . A 2-layer net was partially thermocompression bonded between the embossing roll and the smooth roll at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber non-woven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Example 39]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 32 except that the fiber diameter of each layer was changed to 13 μm. The physical properties of the obtained non-woven fabric are shown in Table 2 below.

[Comparative Example 1]

In the first embodiment, the content of the titanium element of the polyester resin is 3,000 ppm, and the basis weight of the polyester long fiber is 20.0 g/m ² , and the same as in the first embodiment. In this way, polyester long-fiber non-woven fabric is obtained, but the non-woven fabric has low transparency, and sufficient transparency cannot be obtained as a food filter. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 2]

In the first embodiment, the fiber length of the polyester long fibers after melt-spinning at a draw ratio of 545 was set to 12.0 μm, and the basis weight of the polyester long fibers was 20 g/m ² . Except for this, a polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 1, but the nonwoven fabric was low in transparency, and sufficient transparency could not be obtained as a food filter. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 3]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 1 except that a polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 253 ° C was used. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 4]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 2 except that a polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 253 ° C was used. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 5]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 253 ° C was used. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 6]

The titanium content is 12 ppm, the intrinsic viscosity (IV) is 0.65, and the melting point is 253 °C. A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 4 except for the polyester resin. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 7]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 3 except that a polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 253 ° C was used. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 8]

A polyester resin having a titanium content of 0 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 246 ° C is supplied to a conventional melt spinning apparatus and melted at 295 ° C from a spinning hole having a circular cross section. The spinning head was melt-spun at a spinning speed of 4000 m/min and a draw ratio of 191 to obtain a polyester long fiber having a fiber diameter of 30.3 μm. Then, using a flat-shaped dispersing device for controlling the air flow [the inclination angle of the flat plate with respect to the filament is 4°], the fiber is opened and dispersed to produce a net having a basis weight of 20/m ² , and is applied to the embossing roller and the smoothing roller. The partial thermocompression bonding was carried out at a thermocompression bonding area ratio of 15%, whereby a polyester long fiber nonwoven fabric was obtained, but sufficient dimensional stability could not be obtained as a food filter. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 9]

In Comparative Example 8, the fiber diameter of the polyester long fibers which were melt-spun at a draw ratio of 345 was set to 50.0 μm, and the basis weight of the polyester long fibers was 20 g/m ² . However, the shrinkage of the roll is large and the polyester long fiber non-woven fabric cannot be obtained. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 10]

In the third embodiment, a polyester long-fiber nonwoven fabric was obtained in the same manner as in Example 3 except that the basis weight of the polyester long fibers was 40 g/m ² , but the nonwoven fabric was low in transparency. As a food filter, sufficient transparency cannot be obtained. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 11]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 21 except that the titanium content of the resin was 3,000 ppm. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 12]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Comparative Example 11, except that the IV value of the resin was changed to 0.7. The physical properties of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 13]

A polyester resin having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, a melting point of 254 ° C as a core, a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The resin was supplied as a sheath to a conventional melt spinning apparatus and melted at 275 ° C, and the spinning head of a spinning hole having a circular cross section was melt-spun at a spinning speed of 4500 m/min and a flat shaped controlled air flow was used. The dispersing device [the inclination angle of the flat plate with respect to the filament is 4°], the polyester long fiber having a fiber diameter of 14 μm is opened and dispersed, and the web having a basis weight of 15 g/m ² is heated between the embossing roller and the smoothing roller. The crimping area ratio of 15% was subjected to partial thermocompression bonding, whereby a polyester long fiber nonwoven fabric was obtained. The physical properties of the obtained non-woven fabric are shown in Table 3 below. Furthermore, the sealing machine produces severe resin contamination when the obtained non-woven fabric is heat-sealed.

[Comparative Example 14]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 21 except that the weight per unit area of each layer was changed to 10 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 3.

[Comparative Example 15]

A polyester long fiber nonwoven fabric was obtained in the same manner as in Example 26 except that the weight per unit area of each layer was 4 g/m ² . The physical properties of the obtained non-woven fabric are shown in Table 3.

[Industrial availability]

The single-layer or multi-layer polyester long-fiber nonwoven fabric of the present invention is preferably used as a food filter because it is excellent in transparency, dimensional stability, powder leakage property, and component extractability.

Claims (18)

A single-layer or multi-layer polyester long-fiber non-woven fabric, wherein the content of inorganic particles is 0-100 ppm, the pore diameter of 10% is less than 1000 μm, the difference between the pore diameter of 10% point and the pore diameter of 2.3% is 500 or less, and the weight per unit area It is 10~30g/m ² . The single-layer or multi-layer polyester long-fiber non-woven fabric of claim 1 has a thermocompression bonding area ratio of 5 to 40% and an average apparent density of 0.1 to 0.5 g/cm ³ . The single-layer or multi-layer polyester long-fiber non-woven fabric of claim 1 or 2 has an average fiber diameter of 13 to 40 μm. A single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 3, wherein at least one layer contains a peak width generated by a C=O group in the vicinity of 1740 cm ^-1 observed in a Raman spectrum The average value of the full width at half maximum is 18 to 24 cm ^-1 of fiber. A single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 4, wherein at least one of the layers comprises fibers having a crystallinity of 30 to 50%. A single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 5, wherein at least one of the layers comprises fibers having a birefringence of from 0.04 to 0.12. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 6, which has a transparency of 60% or more. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 7, which has a boiling water shrinkage ratio of 2.0% or less. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 8, which has a texture coefficient of 0.5 to 2.0. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 9, wherein at least one of the layers has a tensile strength of 5 N/30 mm or more. A single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 10, wherein at least one of the layers contains a low-melting fiber having a melting point of 240 ° C or less. The polyester long-fiber nonwoven fabric according to any one of claims 1 to 11, which comprises a laminated non-woven fabric obtained by integrating the following a layer and b layer by thermocompression bonding, and a layer: comprising a high melting point resin. Polyester long fiber non-woven fabric b layer of a low melting point resin having a melting point difference of 30 ° C to 150 ° C: a polyester long fiber nonwoven fabric comprising the above high melting point resin. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 12, which has a structure in which the orientation of the fibers of the above-mentioned polyester long-fiber nonwoven fabric is different in the cross-sectional direction. A single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 13, wherein at least one of the layers contains a resin containing 0 to 25% of phthalic acid. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 14, wherein the inorganic-based particles are titanium oxide. A single-layer or multi-layer polyester long-fiber non-woven fabric according to claim 15, which comprises a resin having a titanium content of 0 to 0.1 ppm. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 16, wherein the resin having the non-woven fabric has an IV value of 0.6 or more. A food filter comprising the single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 17.