JP6898482B2 - Single-layer or multi-layer polyester long-fiber non-woven fabric and food filters using it - Google Patents

Description

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

Conventionally, a non-woven fabric made of a resin such as polyethylene, polypropylene, polyester, or polyamide has been used as a packaging material. However, in general, it is required to make the fibers dense in order to utilize the shielding function such as the filter property of the non-woven fabric, and the inside cannot be confirmed. Further, when extracting components of black tea, green tea, oolong tea, etc., the tea bag method is often used as a simple method. Paper is generally used as a packaging material used for tea bags, but there are problems such as poor transparency, invisible contents of the packaging material, and inability to heat-seal.

The following Patent Document 1 discloses a non-woven fabric for tea bags with improved transparency, but there is no description regarding dimensional stability, and no particular attention has been paid to it. Furthermore, the maximum pore diameter measured by the bubble point method (JIS-K-3832) is used as an evaluation for powder leakage, but the pore diameter range suitable for measurement is on the order of nanometers to micrometers, and the pressure is converted. Since the pore size is expressed, it is not a suitable evaluation method for tea leaves that are actually used.
Further, Patent Document 2 below discloses a biodegradable monofilament for tea bags made of poly-Llactic acid and having a fineness of 15 to 35 dtex. Although the monofilament is highly transparent due to its high fineness, the monofilament shrinks in boiling water. There is a problem that the rate is 20% or less and the dimensional stability is low.
Further, in Patent Document 3 below, a core-sheath type composite long fiber having a polyolefin-based polymer as a sheath component and a polyester-based polymer having a higher melting point than the sheath component as a core component is excellent in heat-sealing property. Although the non-woven fabric is disclosed, it has low dimensional stability and there is no description about transparency, so that no particular attention has been paid to it.

Japanese Patent No. 3939326 Japanese Unexamined Patent Publication No. 2001-131826 Japanese Unexamined Patent Publication No. 11-43855

In view of the above-mentioned problems of the prior art, the present invention provides a polyester long-fiber non-woven fabric having excellent transparency, dimensional stability, powder leakage property, and component extractability, and a food filter using the same.

As a result of diligent studies and experiments to solve the above problems, the present inventors have selected a polyester resin having a titanium element content in a specific range, and selected a polyester-based resin, and the structure, fiber diameter, and grain size of the fibers constituting the non-woven fabric. A detailed study was conducted from the viewpoint of the heat-bonded area ratio, and it was found that a non-woven fabric having good spinnability, excellent component extractability as a food filter, and good both transparency and dimensional stability can be obtained. It was. Furthermore, the present invention has been completed by defining the pore size calculated by directly observing the non-woven fabric as an evaluation of powder leakage.

That is, the present invention is as follows.
[1] The content of inorganic particles is 0 to 100 ppm, the 10% point pore size is less than 1000 μm, the difference between the 10% point hole diameter and the 2.3% point hole diameter is 500 or less, and the grain size is 10 to 30 g / m. ² der is, and the surface area per area of the nonwoven fabric is characterized in that it is a 1.0~3.25m ² / m ^2, a single-layer or multi-layer polyester long fiber nonwoven fabric.
[2] The single-layer or multi-layer polyester long-fiber non-woven fabric according to the above [1], wherein the thermocompression bonding area ratio is 5 to 40% and the average apparent density is 0.1 to 0.5 g / cm ^3.
[3] The average fiber diameter of 13 ~ 40 μ m, the [1] or single layer or multi-layer polyester filament nonwoven fabric according to [2].
[4] The average value of the full width at half maximum of the peak width at least one layer according to C = O groups in the vicinity of 1740 cm ^-1 observed in the Raman spectra is constituted by fibers of 18~24cm ^-1, the [1] to [ 3] The single-layer or multi-layer polyester long fiber non-woven fabric according to any one of.
[5] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [4] above, wherein at least one layer is composed of fibers having a crystallinity of 30 to 50%.
[6] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [5] above, wherein at least one layer is composed of fibers having a birefringence of 0.04 to 0.12.
[7] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [6] above, which has a transparency of 65% or more.
[8] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [7] above, wherein the boiling water shrinkage rate is 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 formation coefficient of 0.5 to 2.0.
[10] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [9] above, wherein the tensile strength of at least one layer is 5 N / 30 mm or more.
[11] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [10] above, wherein at least one layer contains low melting point fibers having a melting point of 240 ° C. or lower.
[12] The polyester long-fiber non-woven 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.
Layer a: Polyester long-fiber non-woven fabric made of a high-melting point resin and a low-melting point resin with a melting point difference of 30 ° C to 150 ° C.
Layer b: Polyester long-fiber non-woven fabric made of the refractory resin
[13] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [12], which has a structure in which the orientation of the fibers of the polyester long-fiber non-woven fabric is different in the cross-sectional direction.
[14] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [13] above, wherein at least one layer is made of a resin containing 0 to 25% isophthalic acid.
[15] The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of [1] to [14] above, wherein the inorganic particles are titanium oxide.
[16] The single-layer or multi-layer polyester long-fiber non-woven fabric according to the above [15], 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 non-woven fabric according to any one of [1] to [16] above, wherein the IV value of the resin after being made into a non-woven fabric is 0.6 or more.
[18] A food filter made of the single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of the above [1] to [17].

The spinnability of the fibers constituting the single-layer or multi-layer polyester long-fiber non-woven fabric according to the present invention is good, and the food filter produced by using the non-woven fabric made of the fibers has excellent component extractability, transparency, and dimensions. It has good stability and powder leakage resistance.

It is a schematic diagram which shows an example of the device which controls the air flow, such as a plate-shaped dispersion plate. It is a graph which shows the relationship between the boiling water shrinkage rate and transparency. It is a graph which shows the relationship between the draft ratio and the orientation crystallinity. It is a graph which shows the relationship between a spinning temperature and orientation crystallinity. It is a graph which shows the relationship between a resin IV value and orientation crystallinity.

Hereinafter, embodiments of the present invention will be described in detail.
Typical examples of the polyester-based resin constituting the polyester filaments constituting the polyester filamentous fibers of the present embodiment include polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate as thermoplastic polyesters, which form an ester. Polyester may be a polyester obtained by polymerizing or copolymerizing isophthalic acid, phthalic acid, or the like as an acid component. The thermoplastic polyester is further a biodegradable resin, for example, a poly (α-hydroxy acid) such as polyglycolic acid or polylactic acid, or a copolymer containing these as a main repeating unit element. May be good. These resins may be used alone or in combination of two or more.

Since the polyester long-fiber non-woven fabric of the present embodiment is preferable as having high transparency (low hiding property), it is preferable that the content of inorganic particles usually used as a matting agent in the thermoplastic synthetic fiber non-woven fabric is low.
As the inorganic particles used as the matting agent, either synthetic products or natural products can be used without particular limitation. Examples of the inorganic particles include oxide-based ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, itria, zinc oxide and iron oxide, nitride-based ceramics such as silicon nitride, titanium nitride and boron nitride, and silicon carbide. , Calcium carbonate, aluminum sulfate, aluminum hydroxide, magnesium hydroxide, potassium titanate, talc, kaolin clay, kaolinite, dikite, nacrite, haloysite, pyrophyllite, audinite, montmorillonite, biderite, nontronite, volcon score Ito, saponite, saconite, sineholdite, vermiculite, ceramicin, sericite, amesite, kaolinite, frayponite, brindriaite, bentonite, zeolite, black mica, gold mica, iron mica, yeast night, siderophyllite tetra Examples include ceramics and glass fibers such as ferri iron mica, scale mica, polylysionite, muscovite, celadon stone, iron celadon stone, iron aluminoceradon stone, calcium silicate, magnesium silicate, diatomaceous earth and silica sand. .. These inorganic particles may be used alone or in combination of two or more. From the viewpoint of the reaction activity to the resin, the inorganic particles used are preferably inert inorganic particles such as titanium oxide, magnesium stearate, and calcium stearate.

The range of preferable particle size of the inorganic particles of the polyester resin constituting the polyester filaments 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 size exceeds 1.0 μm, not only the transparency of the non-woven fabric is lowered, but also the stability of spinning is deteriorated, so that spinning defects such as yarn breakage increase.

The preferable content of the inorganic particles in the polyester resin constituting the polyester filaments of the present embodiment is 0 to 100 ppm, preferably 0 to 50 ppm, and more preferably 0 to 0.1 ppm. By setting the content of the inorganic particles in the fiber within the above range, it is possible to sufficiently secure the transparency of the non-woven fabric. Further, when inorganic particles are used as a catalyst, the decomposition reaction of the resin at the time of melt extrusion is suppressed and spinning defects such as yarn breakage can be suppressed by setting the particles within the above range.

As the inorganic particles used as a matting agent for the polyester resin constituting the polyester filaments of the present embodiment, titanium-based particles such as titanium oxide whose reaction activity has been deactivated are used because they are inexpensive and versatile. Is preferable. When titanium element is used as the inorganic particles in the polyester resin constituting the polyester filament of the present embodiment, the preferable content is 0 to 100 ppm, preferably 0 to 50 ppm, and more preferably 0 to 0.1 ppm. Is.
Specifically, it is preferable that the super bright resin is colorless and transparent without the addition of inorganic inert particles such as titanium dioxide used as a matting agent, and further is a resin that does not use a titanium compound as a catalyst. By not using the titanium compound as a catalyst, the decomposition reaction of the resin at the time of melt extrusion is suppressed, and spinning defects such as yarn breakage can be suppressed.

The leakability of inclusions when the polyester long fiber non-woven fabric of the present embodiment is used as a packaging material can be defined by the distribution of pore diameters.
The representative value of the pore diameter can be expressed by the pore diameter at an area ratio of 10% when the area of each pore in the non-woven fabric image is integrated in order from the maximum area to the smaller area, and must be 1000 μm or less. The preferred range is 30 μm or more and 6000 μm or less, the more preferable range is 400 μm or less, the more preferable range is 300 μm or less, and the most preferable is 250 μm or less. Above this range, the texture of the fabric becomes coarse, and it becomes impossible to prevent powder leakage from the inclusions. On the other hand, below this range, the fineness of the fabric becomes fine, so that the transparency of the filter becomes low. In addition, since the fluid resistance of the filter increases, the extraction time increases when it is used as a food filter, which is not practical.

The difference between the 2.3% and 10% points when the large-diameter pore diameter distribution is integrated from the maximum pore diameter must be 0 μm or more and 500 μm or less. The preferred range is 300 μm or less, the more preferred range is 200 μm or less, and the more preferred range is 150 μm or less. In the case of a fabric having a large pore diameter distribution such as a non-woven fabric, a non-woven fabric having excellent powder leakage property can be obtained by setting the frequency of holes having a large diameter within this range. Furthermore, by combining with the above range of 10% pore size, the optimum pore size distribution for packaging tea leaves can be defined.

Further, in the case of holes having the same hole area, it is preferable that the shape has a long diameter and a short diameter like an ellipse rather than a perfect circle. When packaging contents such as tea leaves, the surface is not a smooth sphere, so even if the hole area is the same, if the holes have a long diameter and a short diameter, the tea leaves will be caught around the holes and will not leak easily. In particular, it is the shape of the relatively large pores contained in the non-woven fabric that has a great influence on the leakage of tea leaves and the like. The shape of this hole can be shown by dividing the average of the major diameters of the holes from 2.3% hole diameter to 10% hole diameter by the average of the hole diameters from 2.3% hole diameter to 10% hole diameter. The value is preferably 1.3 or more. Generally, if the transparency of the resin is the same, there is a trade-off relationship when trying to suppress leakage of the contents while maintaining the transparency, and the transparency is the fiber surface area included in a certain area, that is, the fiber diameter. The finer the grain and the larger the texture, the worse it becomes, but the leakability of the contents becomes smaller. From this relationship, one method of suppressing the leakage of the contents while ensuring transparency is to reduce the large pore diameter contained in the non-woven fabric, and the other method is to make the shape of the holes less leaky. Is to do. By combining these two methods, it is possible to obtain a non-woven fabric that is more transparent and suppresses leakage of the contents.

The shape of the polyester filament of the present embodiment may be any fiber cross-section shape depending on the purpose and application, such as a hollow cross section, a core-sheath type composite cross section, a split type composite cross section, and a flat cross section, in addition to the normal round cross section. You can choose.
Since the polyester long fiber non-woven fabric of the present embodiment is used in the shape of a tea bag or the like, it is preferable that the polyester long-fiber non-woven fabric has high adhesive strength by heat-sealing with a bag making machine. In order to obtain heat-sealing properties with good adhesive strength, fibers containing a low melting point resin having a melting point of 240 ° C. or less are laminated on at least one surface of the polyester long-fiber non-woven fabric to provide a heat sealing difference. During processing, only the low melting point resin component softens or melts and functions as an adhesive, so that high heat seal strength can be effectively obtained.

The melting point of the low melting point resin is 30 to 150 ° C. lower than the melting point of the high melting point resin, preferably 30 to 100 ° C. lower. As the low melting point resin, for example, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid and naphthalindicarboxylic acid are polymerized with diols such as ethylene glycol, diethylene glycol, 1,4-butanediol and cyclohexanedimethanol. Examples thereof include copolymerized polyester resins and aliphatic polyester resins such as polylactic acid. Further, the fiber structure is a composite fiber structure composed of two components such as a sheath core structure and side-by-side in addition to a single component, for example, a composite fiber structure having a core having a high melting point and a sheath having a low melting point. However, a high melting point resin such as polyethylene terephthalate or polybutylene terephthalate, and a low melting point resin having a sheath such as a copolymerized polyester or an aliphatic polyester are preferable. The method of laminating the low melting point fibers is, for example, a curtain spray method in which the resin is melted and a semi-melted resin or a fibrous material thereof is applied to the non-woven fabric, or the melted resin is discharged from a nozzle and applied to the non-woven fabric. Examples thereof include a coating method, a method of laminating a high melting point fiber web and a low melting point fiber web, and then joining them with a hot roll or the like to obtain a laminated non-woven fabric.

The low melting point resin is used, for example, when a main aromatic dicarboxylic acid containing terephthalic acid is used as a component, a second type aromatic dicarboxylic acid such as isophthalic acid, phthalic acid, and naphthalindicarboxylic acid is copolymerized. At this time, the amount of the second type aromatic dicarboxylic acid with respect to the total aromatic dicarboxylic acid is 0 to 25%, preferably 0 to 22%, and more preferably 0 to 18%. If an amount exceeding this range is added, the crystallinity will be lowered, and the molecular orientation due to stretching will not occur, so that the spinning stability and the mechanical strength and dimensional stability of the non-woven fabric will be lowered.

The polyester long fiber non-woven fabric of the present embodiment is preferably capable of ultrasonic fusing or heat sealing. The seal strength is preferably 0.1 N / 30 mm or more, more preferably 0.2 N / 30 mm or more. The heat-sealing conditions can be appropriately selected. For example, the heat-sealing temperature conditions are preferably 5 to 80 ° C. lower than the melting point of the resin on the sealing surface.
Further, various other commonly used additive components, for example, impact improving agents such as various elastomers, crystal nucleating agents, anticoloring agents, antioxidants, heat stabilizers, plasticizers, lubricants, as long as the desired effects are not impaired. , Weatherproofing agents, antibacterial agents, colorants, pigments, dyes and other additives can be added.

The polyester long fiber non-woven fabric of the present embodiment can be efficiently produced by the spunbond method. That is, the polyester-based resin is heated and melted and discharged from the spinneret, the obtained spun yarn is cooled by using a known cooling device, and the spun yarn is traction-thinned by a suction device such as air soccer. Subsequently, the yarn group discharged from the suction device is opened and then deposited on a conveyor to form a web. Next, a long fiber spunbonded non-woven fabric is obtained by partially thermocompression bonding the web formed on the conveyor using a thermocompression bonding device such as a heated emboss roll.

When the spunbond method is used, the fiber is not particularly limited, but in order to improve the uniformity of the web, for example, a method of charging the fiber by a corona facility as disclosed in Japanese Patent Application Laid-Open No. 11-131355, or a flat plate shape is used. After opening the fibers by adjusting the velocity distribution of the airflow at the ejection part of the ejector using a device that controls the airflow (see Fig. 1) such as a dispersion plate, the web is sprayed and the web is scattered. It becomes a more preferable manufacturing method by using the method of laminating on the collecting surface while suppressing the above.
The non-woven fabric obtained by the spunbond method has strong cloth strength, has physical characteristics such as short fibers not falling off due to breakage of the bonding portion, and is low in cost and highly productive. It is used in a wide range of applications, mainly in hygiene, civil engineering, construction, agriculture / horticulture, and living materials.

The fiber diameter of the polyester filaments of the present embodiment is 13 to 40 μm, preferably 15 to 40 μm, more preferably 18 to 35 μm, and particularly preferably 21 to 30 μm. If the fiber diameter is 13 μm or more, the transparency can be designed to be sufficient. In addition, if the fiber diameter is 40 μm or less because the fiber cannot sufficiently withstand the tension of the ejector during spinning and there is little risk of part of the fiber being cut, it is made into a non-woven fabric and has mechanical strength when used as a food filter. It has excellent rigidity, component extractability, transparency, and sealing properties, and is suitable as a food filter.

The surface area per area of the polyester long-fiber non-woven fabric of the present embodiment (that is, the specific surface area of the long-fiber non-woven fabric m ² / g × ^{grain g / m 2} ) is 1.0 to 3.5 (m ² / m ² ), more preferably. 1.2 to 3.0 (m ² / m ² ), a particularly preferred range is 1.3 to 2.7 (m ² / m ² ). If the surface area per area is 3.5 (m ² / m ² ) or less, the transparency can be designed to be sufficient. Further, if the surface area per area is 1.0 or more, a sufficient number of fibers can be obtained when the non-woven fabric is formed, so that when used as a food filter, the mechanical strength, rigidity, component extractability, and sealing property are improved. Excellent and suitable as a food filter.

The layer structure of the polyester long fiber non-woven fabric of the present embodiment is not particularly limited as long as it is a method of thermally / chemically integrating to form a non-woven fabric, but it can be a laminated non-woven fabric. At this time, it is preferable to have a layer structure in which the roles played by each layer are separated. For example, by making the first layer a layer with high heat-sealing strength and the other layer having excellent mechanical strength such as tensile strength, rigidity, and dimensional stability, the sealing characteristics required at the time of bag making are excellent and the mechanical properties are excellent. It can also be an excellent non-woven fabric. Further, in the process of making a bag-shaped non-woven fabric, if a non-woven fabric having a structure in which mechanical strength and sealing characteristics are compatible with only one layer is used, it is heated at a high temperature in the process of manufacturing a bag by heat bonding processing. Since the crimping process is applied, the thermoplastic resin melts and adheres to the heat rolls and hot plate heaters of the bag making equipment, resulting in deterioration of product quality and processing speed. You will not be able to get it. On the other hand, in the case of the non-woven fabric structure of the present embodiment, by arranging the sealing layer on the inner surface, it is possible to produce the product without deteriorating the quality and the production speed while exhibiting good sealing strength.

When a laminated non-woven fabric is used as the polyester long-fiber non-woven fabric of the present embodiment, the structure of the layer responsible for the sealing property is a single fiber structure such as a spunbond method or a melt blown method, a sheath core structure, a side-by-side structure, a split split fiber, or the like. Although a composite fiber structure made of the above can be used, it is preferable that the structure is such that the low melting point resin which is responsible for the sealing performance is arranged on the fiber surface. For example, it has a composite fiber structure in which the core has a high melting point and the sheath has a low melting point. Specifically, the core is a high melting point resin such as polyethylene terephthalate or polybutylene terephthalate, and the sheath is a copolymerized polyester or an aliphatic polyester as described above. It is a non-woven fabric having a sheath core structure composed of a low melting point resin.

When a laminated non-woven fabric is used as the polyester long-fiber non-woven fabric of the present embodiment, the method for producing the layer that bears mechanical strength is not particularly limited, but the spunbond method is preferable from the viewpoint of productivity and the like.
In particular, when a laminated non-woven fabric is used as the polyester long fiber non-woven fabric of the present embodiment, the non-woven fabric having more excellent dimensional stability and mechanical strength can be obtained by producing the layer that bears mechanical strength by the above method. be able to.

The crimping method when a laminated non-woven fabric is used as the polyester long-fiber non-woven fabric of the present embodiment is not particularly limited as long as the fibers can be integrated into a non-woven fabric, but after laminating each layer, thermocompression bonding is performed with a thermal roll or the like. It is preferable to make the non-woven fabric. By thermocompression bonding after laminating each layer, the adhesive strength between the layers can be further strengthened, and the mechanical strength and sealing performance can be more effectively exhibited.

By setting the layer structure of the laminated non-woven fabric in the present embodiment to the above-mentioned laminated structure, the sealing strength can be further set in a more suitable range. The specific seal 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 can be further set in a more preferable range, and the range is 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 non-woven fabric of the present embodiment is not particularly limited as long as it is a method of thermocompression-bonding the threads of the non-woven fabric, but between a pair of heating rolls composed of an embossed roll having an uneven surface structure and a flat roll. This can be preferably performed by passing the non-woven fabric through the non-woven fabric to form thermocompression-bonded portions evenly dispersed throughout the non-woven fabric. When thermocompression bonding is performed by embossing roll, it is preferable that thermocompression bonding is performed at a thermocompression bonding area ratio in the range of 5 to 40% with respect to the total area of the non-woven fabric, more preferably 7 to 30%, still more preferably. It is 7 to 20%.
When the thermocompression bonding area ratio is within this range, good thermocompression bonding between fibers can be performed, and appropriate mechanical strength, rigidity, transparency, component extractability, and dimensional stability of the obtained non-woven fabric are achieved. Preferred above. The thermocompression bonding temperature and pressure should be appropriately selected depending on the conditions such as the basis weight and speed of the supplied web, and are not unconditionally determined, but are 10 to 90 ° C lower than the melting point of the polyester resin. The temperature is preferably 20 to 60 ° C. lower.

In addition to using the embossed roll in the thermocompression bonding step, an air-through method in which the threads are thermocompression-bonded by passing hot air through the web can be used. When thermocompression bonding is performed by the air-through method, the surface of the fabric is not partially uneven like an embossed shape, so that the appearance of the non-woven fabric can be made more transparent.

The boiling water shrinkage rate of the polyester long fiber nonwoven fabric of the present embodiment is preferably 2.0% or less, more preferably 1.6% or less, still more preferably 1.0%, and a particularly preferable range is 0.5% or less. When the boiling water shrinkage rate is 2.0% or less, there is almost no shrinkage in thermoforming, process stability is excellent, and morphological retention is excellent even in a usage form exposed to a high temperature environment close to 100 ° C. The lower limit is preferably 0%, but in reality it is 0.2% or more.

The transparency of the polyester long fiber non-woven 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%, the state of the contents is difficult to see through the non-woven fabric and becomes unclear.

The basis weight of the polyester long fiber non-woven fabric of the present embodiment is 10 to 30 g / m ² , preferably 12 to 25 g / m ² . If the basis weight is 10 g / m ² or more, sufficient mechanical strength can be secured while maintaining transparency and component extractability. On the other hand, if the basis weight is 30 g / m ² or less, transparency and component extractability can be obtained.

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

The average apparent density of the polyester long fiber non-woven fabric of the present embodiment ^{is preferably 0.10 to 0.50 g / cm 3} , and more preferably 0.12 to 0.30 g / cm ³ . The average apparent density is related to the rigidity, transparency, powder leakage property and component extractability of the non-woven fabric, and the fiber gap is appropriate in the above range, so that it is suitable as a food filter. If the average apparent density is 0.10 g / cm ³ or more, the mechanical strength can be sufficiently obtained while adjusting the fiber gaps and appropriately suppressing the amount of powder leakage. On the other hand, if the average apparent density is 0.50 g / cm ³ or less, the fiber gaps are not made too small, the component extractability can be maintained appropriately, and the product quality can be sufficiently obtained.

The tensile strength of the polyester long fiber nonwoven fabric of the present embodiment in the MD direction is preferably 5 to 40 N / 30 mm, more preferably 6 to 40 N / 30 mm, and even more preferably 7 to 40 N / 30 mm. If the tensile strength is equal to or higher than this range, it is excellent in production stability during bag making and prevention of tearing when used as a food filter.

The formation coefficient of the polyester long fiber non-woven fabric of the present embodiment is preferably 0.5 to 2.0, more preferably 0.5 to 1.5. The formation coefficient is related to strength, rigidity, transparency, powder leakage property and component extractability because it indicates the uniformity of the non-woven fabric. Within the above range, the uniformity of the non-woven fabric is optimal, so that it is excellent in strength, rigidity, transparency, processability into a bag shape, and powder leakage property as a food filter.

The spinning temperature at the time of obtaining the polyester filaments of the present embodiment is preferably a temperature 10 to 60 ° C. higher than the melting point of the polyester resin, and more preferably 10 to 30 ° C. higher. When the spinning temperature is in this range, no single yarn breakage or the like occurs, the orientation crystallinity is appropriate, and a non-woven fabric having excellent mechanical strength and dimensional stability can be obtained.

The intrinsic viscosity (IV value) of the resin after making the non-woven fabric of the polyester long fiber non-woven fabric of the present embodiment is preferably 0.6 or more, more preferably 0.65 or more, and further preferably 0.7 or more. When the resin pellets are melt-extruded, the resin decomposes due to the heat load during melting and the shear load during kneading. When the IV value of the resin after melting, that is, after making it into a non-woven fabric is in this range or more, the decomposition of the resin can be suitably suppressed, and the stretching and crystallization of the resin during spinning can be promoted. A non-woven fabric having excellent mechanical strength and dimensional stability can be obtained.

The spinning speed for obtaining the polyester filaments of the present embodiment is preferably 3000 to 6000 m / min, more preferably 3500 to 5000 m / min. When the traction speed at the time of traction thinning of the spun yarn is within the above range, a non-woven fabric having sufficient orientation crystallization of polyester filaments and excellent mechanical properties and dimensional stability can be obtained, and spinning. There is little possibility that thread breakage will occur inside, which is preferable from the viewpoint of the productivity of the non-woven fabric.

The draft ratio for obtaining the polyester filaments of the present embodiment is preferably 400 to 2500, more preferably 700 to 2200. When the draft ratio at the time of pulling and thinning the spun yarn is within the above range, a non-woven fabric having sufficient orientation crystallization of polyester filaments and excellent mechanical properties and dimensional stability can be obtained, and the spun yarn is spun. It is also preferable from the viewpoint of the productivity of the non-woven fabric because it is unlikely that thread breakage or "roll removal" during thermocompression bonding will occur inside.

The birefringence Δn of the polyester filaments of the present embodiment is 0.04 to 0.12, preferably 0.06 to 0.1. When the birefringence is in this range, a non-woven fabric having appropriate fiber orientation and excellent mechanical strength and dimensional stability can be obtained.

The method for evaluating the crystallinity is not particularly limited, and for example, the crystallinity can be measured by DSC, Raman spectroscopy, or the like.

The crystallinity of the polyester filaments of the present embodiment is 30 to 50%, preferably 40 to 50%. When the crystallinity is within this range, fibers having excellent mechanical strength and dimensional stability can be obtained.

When the crystallinity of the polyester filaments of the present embodiment is carried out by Raman spectroscopy, it is evaluated by the average value of the full width at half maximum of the peak width due to the C = O group near ^{1740 cm -1 observed in the Raman spectrum of the fiber cross section.} Can be done. 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 the more preferable range is 20 to 23 cm ^-1 . When the average value of the full width at half maximum of the peak width is in this range, a fiber having excellent mechanical strength and dimensional stability can be obtained.

The polyester filaments of the present embodiment have different crystallinity in the radial direction of the fiber, for example, the crystallinity of the outer peripheral portion can be increased and the crystallinity of the inside can be decreased. By increasing the crystallinity of the outer peripheral portion, it is possible to obtain fibers that are less likely to shrink and have excellent mechanical strength, and by lowering the crystallinity of the inside, sufficient pressure bonding strength between the fibers can be obtained during thermocompression bonding. As a result, a non-woven fabric having excellent mechanical strength and dimensional stability can be obtained. This can be confirmed by evaluating the melting peak when measuring the crystallinity by DSC.

FIG. 2 shows the relationship between the boiling water shrinkage rate and the transparency of the polyester long fiber non-woven fabric in the examples of the present invention. Although the transparency can be increased by increasing the fiber diameter, the boiling water shrinkage rate increases and the dimensional stability decreases because the orientation crystallization does not proceed easily.

FIGS. 3 and 4 show the relationship between the draft ratio and the spinning temperature of the polyester long fiber non-woven fabric in the examples of the present invention and the orientation crystallinity indicated by the birefringence (Δn) and the crystallinity, respectively. The larger the draft ratio, the greater the orientation crystallinity of the fibers. Further, under the spinning conditions of a large fiber diameter, the lower the spinning temperature, the higher the cooling property, the higher the drawing efficiency, and the more the alignment and crystallization of the fibers can be promoted.

FIG. 5 shows the relationship between the intrinsic viscosity (IV value) of the resin of the polyester long fiber non-woven fabric in the examples of the present invention and the orientation crystallinity indicated by the birefringence (Δn) and the crystallinity. By increasing the IV value of the resin, the orientation crystallization of the resin is promoted, and the orientation crystallization of the fibers can be promoted.

From these data, as a result of diligent research to achieve the desired effect of the present invention, the inventors of the present invention have improved the oriented crystallinity while maintaining the large fiber diameter by lowering the spinning temperature and increasing the draft ratio. Achieved both transparency and improved boiling water shrinkage. That is, although there is a contradictory relationship between the improvement of transparency and the improvement of dimensional stability expressed by the boiling water shrinkage rate in the non-woven fabric, the present inventors set the optimum range of fiber diameter increase and orientation crystallinity. As a result, both improvement in transparency and improvement in dimensional stability have been achieved.

Further, in the present invention, the optimum range of the oriented crystal can be achieved by optimizing the intrinsic viscosity (IV value) of the resin used. The range of IV values for achieving this purpose is 0.7 or more, preferably 0.85 or less, and more preferably 0.72 to 0.8. If the intrinsic viscosity is in this range, stable productivity can be ensured without single thread breakage, and higher dimensional stability can be obtained by obtaining high orientation crystallinity when the molten resin is towed and thinned. Sexual and mechanical strength can be obtained.

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

The polyester long fiber non-woven fabric of the present embodiment may be subjected to regular post-processing, for example, a deodorant, an antibacterial agent, etc., as long as the desired effect of the present invention is not impaired, and may be dyed or water repellent. Processing, water permeable processing, etc. may be performed.
The polyester long-fiber non-woven fabric of the present embodiment has excellent transparency, so that the contents can be seen clearly, so that it has excellent design, and because it has excellent dimensional stability, it has excellent filters for foods such as green tea, black tea, and coffee. It has very suitable properties as. The food filter may be a flat bag, but a three-dimensional shape is preferable because the contents can be seen better and extraction can be performed effectively. As the three-dimensional shape, a tetrahedron shape, a triangular pyramid three-dimensional shape, or the like is preferable.

Three-dimensional food filters are sold after being filled with the extract and sealed in a bag, but when the consumer who purchased the filter takes it out of the bag and uses it, it can quickly return to the original three-dimensional shape. Required. Since the long-fiber non-woven fabric of the present invention is elastic and has appropriate rigidity, the above requirements can be sufficiently satisfied.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. The measurement method, evaluation method, etc. used were as follows.

(1) Titanium element content (ppm)
The titanium element content in the polyester resin was determined using an ICP emission spectrometer manufactured by Thermo Fisher Scientific.

(2) Average fiber diameter (μm)
Using a microscope microscope (VH-8000) manufactured by KEYENCE, the diameter of the fiber was magnified 1000 times and measured, and the average value of each of the 20 fibers was calculated.

(3) Birefringence index (Δn)
Using a BH2 type polarizing microscope compensator manufactured by OLYMPUS, the birefringence of the fiber immediately after traction was determined from the retardation and the fiber diameter by the usual interference fringe method.

(4) Crystallinity (%)
Using a differential scanning calorimeter DSC6000 manufactured by PerkinElmer, the temperature was raised from 40 ° C. to 300 ° C. at a heating rate of 10 ° C./min to measure the calorific value of crystallization ΔHc and the calorific value of crystal melting ΔHm. The crystallinity (%) was calculated by the following formula:
Crystallinity χc (%) = (ΔHm−ΔHc) / 126.4 × 100
* 126.4 J / g is the amount of heat of fusion of the perfect crystal of polyethylene terephthalate.

(5) Full width at half maximum (cm ^-1 )
The spectrum was measured with an excitation light of 532 nm and an excitation light intensity of 10% using a microscopic Raman spectroscope manufactured by Renishaw. The full width at half maximum of the peak width due to the C = O group near ^{1740 cm -1} observed in the spectrum was determined.

(6) Intrinsic viscosity (IV value)
Measured according to JIS K-7637-5.

(7) Metsuke (g / m ² )
Measured according to JIS L-1906.

(8) Thickness (mm)
The thickness of a 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 from the basis weight and thickness measured by the method specified in JIS L-1906:
Average apparent density (g / cm ³ ) = (Metsuke g / m ² ) / ((Thickness mm) x 1000)

(10) Thermocompression bonding area ratio (%)
A 1 cm square test piece was sampled and a photograph was taken with an electron microscope, the area of the thermocompression bonding portion was measured from each photograph, and the average value was taken as the area of the thermocompression bonding portion. Further, the pitch of the pattern of the thermocompression bonding portion was measured in the MD direction and the CD direction, and the ratio of the thermocompression bonding area to the unit area of the non-woven fabric was calculated as the thermocompression bonding area ratio from these values.

(11) Transparency (%)
Measure the reflectance (L value) with a Macbeth spectrophotometer (CE-7000A type: manufactured by Sakata Ink), and find the difference between _{the L value (L w0} ) of the standard whiteboard and the L value (L _{b0) of the standard blackboard. Then, the transparency was calculated from the L value (L b} ) placed on the blackboard in the same way as the L value (L _w ) placed on the white board 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, 3 test pieces of 25 cm in length × 25 cm in width were collected per 1 m of width of the sample, immersed in boiling water for 3 minutes, and after natural drying, the shrinkage ratios in the MD direction and the CD direction were determined. The average value of each was calculated, and the shrinkage rate in the MD direction or the CD direction, whichever was larger, was taken as the boiling water shrinkage rate of the non-woven fabric.

(13) Tensile strength (N / 30mm)
Using the Shimadzu Autograph AGS-5G type, a sample with a width of 30 mm is grasped and stretched at a length of 100 mm and a tensile speed of 300 mm / min. Was performed, and the average value was calculated.

(14) Formation coefficient
A 20 cm x 30 cm test piece was collected, and a transmission image taken in a range of 18 cm x 25 cm with a CCD camera using a formation tester (FMT-MIII) measuring instrument manufactured by Nomura Shoji was decomposed into 128 x 128 pixels, and each of them was decomposed into 128 x 128 pixels. The intensity of light received by the pixels was measured, and the transmittance was calculated. The formation coefficient is a value obtained by dividing the standard deviation (σ) of the transmittance of each minute part (5 mm × 5 mm) of the measurement sample by the average transmittance (E), and represents the variation in the minute unit grain, and the value is small. The more uniform it is, the higher the uniformity.
Formation coefficient = σ / E × 100

(15) Heat seal strength (N / 30mm)
Using the Shimadzu Autograph AGS-5G type, the heat-sealed part of the sample with a width of 30 mm is peeled off in the vertical direction by about 50 mm and attached, and it is stretched at a grip length of 50 mm and a tensile speed of 100 mm / min. Taking the load as the strength, the measurement was performed 5 times in the MD direction of the non-woven fabric, and the average value was calculated. The heat sealing conditions were 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) Draft ratio The draft ratio was calculated from the following formula:
Draft ratio = Spinning speed (m / min) / Discharge line speed (m / min)
Discharge line velocity (m / min) = Single hole discharge amount (g / min) / {Melting density (g / cm ³ ) x [Spin diameter (cm) / 2] ² x π}
* Polyester melt density: 1.20 g / cm ³ is used

(17) Surface area per area of polyester long-fiber non-woven fabric The specific surface area of the long-fiber non-woven fabric was determined by ^{m 2} / g × grain g / m ^{2.
The specific surface area (m 2} / g) of the long-fiber non-woven fabric was determined by the automatic specific surface area measuring machine Gemini 2360 manufactured by Shimadzu Corporation. When the specific surface area was less ^{than 0.1 m 2} / g, it was calculated by the following formula.
Surface area (m ² / m ² ) = 4 x grain (g / m ² ) / resin density (g / cm ³ ) / fiber diameter (μm)
In the case of sheets having two or more fiber diameters, the surface areas of each fiber diameter were totaled.

(18) 10% pore size Ten pieces of 2 cm square material were cut out from one sample, platinum was vapor-deposited with an ion sputtering device for SEM observation, and non-woven fabric images at 10 places in one sample were obtained at a magnification of 100 times with transmitted light. I took a picture. The image was binarized to black for the non-woven fabric and white for the holes using image analysis software, and the areas and longest diameters of all the holes in the image were quantified. As the image analysis software, "A image-kun (TM)" manufactured by Asahi Kasei Engineering Co., Ltd. was used. All the holes in one sample image are arranged in order from the maximum area to the smallest area and integrated, and from the hole area at the point where 10% of the total hole area is reached, the diameter of the circle having the same area as the area is as follows. The hole diameter was calculated by the formula of.
Hole diameter (μm) = ((4 × S) / π) ^ 0.5
In the above formula, S means the hole area (μm ^ 2), and “^ 0.5” means “0.5 power”.

(19) 2.3% hole diameter Instead of the above 10% hole diameter, the hole diameter was calculated from the hole area at the point where 2.3% of the total hole area was reached.

(20) Major axis / hole diameter All holes in one sample image are arranged in order from the maximum area to the smallest area and integrated, and all included between the holes reaching 2.3% and the holes reaching 10% of the total hole area. The average of the major axis and the average of the hole diameter of the holes were calculated by the following formula.
Major axis / hole diameter = average major axis / average hole diameter

[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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.5 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 2120. Next, using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] to control the air flow in a flat plate shape, the fibers are spread and dispersed to ^{prepare a web with a grain size of 12 g / m 2} , and between the embossed roll and the flat roll. A polyester long fiber non-woven fabric was obtained by thermocompression bonding at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 2]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 1 except that the polyester long fibers were spun so as to have a fiber diameter of 25.7 μm in Example 1. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 3]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 1 except that the polyester long fibers were spun so as to have a fiber diameter of 30.0 μm in Example 1. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 4]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 5]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 6]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 7]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 8]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 3 except that the polyester long fiber non-woven fabric was spun so as to have a basis weight of 20 g / m ^{2 in Example 3.} The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 9]
A polyester long fiber non-woven fabric was prepared in the same manner as in Example 1 except that the polyester long fibers were melt-spun at a spinning speed of 3770 m / min and a draft ratio of 707 in Example 1 and spun so that the fiber diameter of the polyester long fibers was 34.9 μm. Obtained. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 10]
A polyester long-fiber non-woven fabric was obtained in the same manner as in Example 2 except that the polyester long-fiber non-woven fabric was spun so as to have a texture of 20 g / m ^{2 in Example 2 and thermocompression-bonded to the entire surface with a flat roll.} The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 11]
A polyester resin having a titanium element 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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 30.1 μm was obtained by melt spinning at a spinning speed of 4000 m / min and a draft ratio of 942. Next, using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] to control the air flow in a flat plate shape, the fibers are spread and dispersed to ^{prepare a web having a grain size of 20 g / m 2} , and between the embossed roll and the flat roll. A polyester long fiber non-woven fabric was obtained by thermocompression bonding at a thermocompression bonding area ratio of 5%. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 12]
A polyester resin having a titanium element 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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 30.0 μm was obtained by melt spinning at a spinning speed of 4000 m / min and a draft ratio of 942. Next, the fibers were spread and dispersed to ^{prepare a web having a grain size of 12 g / m 2} , and a polyester long fiber non-woven fabric was obtained by partially thermocompression bonding between the embossed roll and the flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 13]
A polyester resin having a titanium element 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 device and melted at 275 ° C. A disperser [inclination angle 4 ° with respect to the filament of the flat plate] is used to open polyester filaments with a fiber diameter of 26.7 μm by melt spinning at a spinning speed of 4000 m / min and a draft ratio of 942. A web having a grain size of 18 g / m ^{2 was prepared by finely dispersing the fibers.} Next, a polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C is supplied to a conventional melt spinning apparatus and melted at 275 ° C to have a spinning hole having a circular cross section. A disperser [inclination angle 4 ° with respect to the filament of the flat plate] is used to control the flat flow of polyester filaments with a fiber diameter of 15 μm by melt spinning from the spinneret at a spinning speed of 4150 m / min and a draft ratio of 412. , A web with a grain of 3 g / m ² was prepared by spreading and dispersing. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 14]
A polyester resin having a titanium element 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 device and melted at 275 ° C. A disperser [inclination angle 4 ° with respect to the filament of the flat plate] is used to open polyester filaments with a fiber diameter of 24.6 μm by melt spinning at a spinning speed of 4000 m / min and a draft ratio of 942. A web having a grain size of 10 g / m ^{2 was prepared by finely dispersing the fibers.} Next, 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 is used as a core, and a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.65 and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning apparatus and melted at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 895 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 8 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 20 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 15]
A polyester long-fiber non-woven fabric was obtained in the same manner as in Example 1 except that the polyester long-fiber non-woven fabric was spun so as to have a basis weight of 18 g / m ^2. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 16]
Except that the basis weight of the polyester filament non-woven fabric is spun such that the 18 g / m ² in Example 2, to obtain a polyester long fiber nonwoven fabric in the same manner as in Example 1. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 17]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 1 except that the polyester long fiber non-woven fabric was spun so as to have a basis weight of 18 g / m ^{2 in Example 3.} The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[ Reference Example 18]
In Example 1, the polyester long fiber non-woven fabric had a basis weight of 18 g / m ^2, and was used as the first-layer non-woven fabric. A 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 ^{under the conditions of a spinning temperature of 260 ° C. and heated air of 500 Nm 3} / hr / m, and obtained a fiber diameter of 10 μm. A melt-brown non-woven fabric was sprayed onto the above-mentioned spun-bonded non-woven fabric at a meshing point of 5 g / m ² to obtain a laminate of the non-woven fabric. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 19]
In Example 2, the polyester long fiber non-woven fabric had a basis weight of 18 g / m ^2, and was used as the first-layer non-woven fabric. A 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 ^{under the conditions of a spinning temperature of 255 ° C. and heated air of 400 Nm 3} / hr / m, and obtained a fiber diameter of 15 μm. A melt-brown non-woven fabric was sprayed onto the above-mentioned spun-bonded non-woven fabric at a meshing point of 4 g / m ² to obtain a laminate of the non-woven fabric. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 20]
In Example 3, the polyester long fiber non-woven fabric had a basis weight of 18 g / m ^2, and was used as the first-layer non-woven fabric. A 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 ^{under the conditions of a spinning temperature of 265 ° C. and heated air of 1000 Nm 3} / hr / m, and obtained a fiber diameter of 7 μm. A melt-brown non-woven fabric was sprayed onto the above-mentioned spun-bonded non-woven fabric at a meshing point of 4 g / m ² to obtain a laminate of the non-woven fabric. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 21]
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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 14 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 230. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning apparatus and melted at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 380 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 14 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 22]
A polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.1 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 590. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning apparatus and melted at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 380 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 14 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 23]
A polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning device and melted at 275 ° C. A polyester filament having a fiber diameter of 24.6 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 740. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning apparatus and melted at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 380 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 14 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 24]
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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.1 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 550. Next, a web having ^{a basis weight of 10 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning device to melt at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 450 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 16 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] for controlling a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 25]
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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.1 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 590. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning device to melt at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 450 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 16 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 26]
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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 24.6 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 740. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning device to melt at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 450 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 16 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 27]
A polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.1 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 590. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 0 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning device to melt at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 450 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 16 μm using a disperser [inclination angle 0 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 28]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 22 except that the inclination angle of the flat plate of the disperser for controlling the flat air flow with respect to the filament was set to 0 °. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[Example 29]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 21 except that the layer using the low melting point resin was changed from a sheath core structure to a side-by-side structure. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 30]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 24 except that the layer using the low melting point resin was changed from a sheath core structure to a side-by-side structure. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 31]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 22 except that the layer using the low melting point resin was changed from a sheath core structure to a side-by-side structure. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 32]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 21 except that the basis weight of each layer was 6 g / m ^2. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 33]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 22 except that the basis weight of each layer was 6 g / m ^2. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 34]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 35]
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 device and melted at 275 ° C. A polyester filament having a fiber diameter of 20.1 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 590. Next, a web having ^{a basis weight of 12 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning device to melt at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 450 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 6 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 16 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 36]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 25 except that the basis weight of each layer was 9 g / m ^2. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[ Reference Example 37]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 21 except that the basis weight of each layer was 9 g / m ^2. The physical characteristics of the obtained non-woven fabric are shown in Table 1 below.

[ Reference Example 38]
A polyester resin having a titanium element content of 12 ppm, an intrinsic viscosity (IV) of 0.8, and a melting point of 247 ° C is supplied to a conventional melt spinning device and melted at 305 ° C. A polyester filament having a fiber diameter of 10 μm was obtained by melt spinning at a spinning speed of 4500 m / min and a draft ratio of 230. Next, a web having ^{a basis weight of 7.5 g / m 2} was prepared by spreading and dispersing the fibers using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. Next, 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 is used as a core, and a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. The polyester-based resin is used as a sheath and is supplied to a conventional melt-spinning apparatus and melted at 275 ° C., and spin-spun at a spinning speed of 4500 m / min and a draft ratio of 380 from a spinneret having a spinning hole with a circular cross section. ^{A web having a grain size of 7.5 g / m 2} was prepared by spreading and dispersing polyester filaments having a fiber diameter of 14 μm using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] that controls a flat air flow. A polyester long fiber non-woven fabric was obtained by partially thermocompression bonding a two-layer web between an embossed roll and a flat roll at a thermocompression bonding area ratio of 15%. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Example 39]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 32 except that the fiber diameter of each layer was 13 μm. The physical characteristics of the obtained non-woven fabric are shown in Table 2 below.

[Comparative Example 1]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 1 except that the polyester resin had a titanium element content of 3000 ppm and ^{was spun so that the polyester filament had a texture of 20.0 g / m 2.} However, the transparency of the non-woven fabric was low, and sufficient transparency could not be obtained as a food filter. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 2]
Polyester in the same manner as in Example 1 except that the fiber diameter of the polyester filaments melt-spun at a draft ratio of 545 was set to 12.0 μm and the polyester filaments were spun so as to have a grain size of 20 g / m ^2. A long-fiber non-woven fabric was obtained, but the transparency of the non-woven fabric was low, and sufficient transparency could not be obtained as a food filter. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 3]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 4]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 5]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 6]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 4 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 characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 7]
A polyester long fiber non-woven 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 characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 8]
A polyester resin having a titanium element 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 device and melted at 295 ° C. A polyester filament having a fiber diameter of 30.3 μm was obtained by melt spinning at a spinning speed of 4000 m / min and a draft ratio of 191. Next, using a disperser [inclination angle 4 ° with respect to the filament of the flat plate] to control the air flow in a flat plate shape, the fibers are spread and dispersed to ^{prepare a web with a grain size of 20 / m 2} , and between the embossing roll and the flat roll. A polyester long fiber non-woven fabric was obtained by thermocompression bonding at a thermocompression bonding area ratio of 15%, but sufficient dimensional stability could not be obtained as a food filter. The physical characteristics 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 filaments melt-spun at a draft ratio of 345 was set to 50.0 μm, and the polyester filaments ^{were spun so that the grain size was 20 g / m 2} , but the shrinkage on the roll was large and the polyester filaments were spun. The non-woven fabric could not be obtained. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 10]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 3 except that the web was prepared so that the grain size of the polyester long fibers was 40 g / m ^{2 in Example 3, but the transparency of the non-woven fabric was low and the food was prepared.} Sufficient transparency could not be obtained as a filter. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 11]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 21 except that the titanium content of the resin was 3000 ppm. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 12]
A polyester long fiber non-woven fabric was obtained in the same manner as in Comparative Example 11 except that the IV value of the resin was 0.7. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below.

[Comparative Example 13]
A polyester-based resin with a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 254 ° C is used as a core, and a polyester having a titanium element content of 0 ppm, an intrinsic viscosity (IV) of 0.65, and a melting point of 217 ° C. A polyester filament with a fiber diameter of 14 μm is melt-spun at a spinning speed of 4500 m / min from a spinneret having a spinning hole with a circular cross section by supplying the based resin as a sheath to a conventional melt-spinning device and melting at 275 ° C. Using a disperser that controls the flat air flow [inclination angle 4 ° with respect to the filament of the flat plate], spread the fibers and disperse ^{the web with a grain size of 15 g / m 2} between the embossed roll and the flat roll with a thermal pressure bonding area ratio of 15%. A polyester long fiber non-woven fabric was obtained by partial heat crimping. The physical characteristics of the obtained non-woven fabric are shown in Table 3 below. When the obtained non-woven fabric was heat-sealed, resin stains were severely generated on the sealer.

[Comparative example 14]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 21 except that the basis weight of each layer was 10 g / m ^2. Table 3 shows the physical characteristics of the obtained non-woven fabric.

[Comparative example 15]
A polyester long fiber non-woven fabric was obtained in the same manner as in Example 26 except that the basis weight of each layer was 4 g / m ^2. Table 3 shows the physical characteristics of the obtained non-woven fabric.

The single-layer or multi-layer polyester long-fiber non-woven fabric of the present invention is excellent in transparency, dimensional stability, powder leakage property, and component extractability, and therefore can be suitably used as a food filter.

Claims (16)

The content of inorganic particles is 0 to 100 ppm, the 10% point pore size is less than 1000 μm, the difference between the 10% point hole diameter and the 2.3% point hole diameter is 500 μm or less, and the grain size is 10 to 30 g / m ² . A single-layer or multi-layer polyester long-fiber non-woven fabric, characterized in that the surface area per area of the non-woven fabric is 1.0 to 3.25 ^{m 2} / m ² and the formation coefficient is 0.5 to 2.0. The single-layer or multi-layer polyester long-fiber non-woven fabric according to claim 1, wherein the thermocompression bonding area ratio is 5 to 40% and the average apparent density is 0.1 to 0.5 g / cm ^3. The single-layer or multi-layer polyester long-fiber non-woven fabric according to claim 1 or 2, wherein the average fiber diameter is 13 to 40 μm. The average value of the full width at half maximum of the peak width by C = O groups in the vicinity of 1740 cm ^-1 of at least one layer is observed in the Raman spectra is constituted by fibers of 18~24cm ^-1, one of claims 1 to 3 1 The single-layer or multi-layer polyester long fiber non-woven fabric according to the item. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 4, wherein at least one layer is composed of fibers having a crystallinity of 30 to 50%. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 5, wherein at least one layer is composed of fibers having a birefringence of 0.04 to 0.12. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 6, which has a transparency of 65% or more. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 7, wherein the boiling water shrinkage rate is 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, wherein the tensile strength of at least one layer is 5 N / 30 mm or more. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 9, wherein at least one layer contains low melting point fibers having a melting point of 240 ° C. or lower. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 10, which has a structure in which the orientation of the fibers of the polyester long-fiber non-woven fabric is different in the cross-sectional direction. The single-layer or multi-layer polyester long-fiber nonwoven fabric according to any one of claims 1 to 11, wherein at least one layer is made of a resin containing 0 to 25% of isophthalic acid. The single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 12, wherein the inorganic particles are titanium oxide. The single-layer or multi-layer polyester long-fiber non-woven fabric according to claim 13, which comprises a resin having a titanium element 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 14, wherein the IV value of the resin after forming the non-woven fabric is 0.6 or more. A food filter made of a single-layer or multi-layer polyester long-fiber non-woven fabric according to any one of claims 1 to 15.

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