JP4737039B2 - Filter nonwoven fabric for air intake - Google Patents

Description

  The present invention relates to a non-woven fabric for an intake filter that is excellent in dust collection performance and air permeability, and further excellent in mechanical properties and dimensional stability.

  2. Description of the Related Art Conventionally, filter media used as a filter for intake air such as a turbine have been made by adding a binder to glass fiber, or by electretizing a nonwoven fabric made of polypropylene (PP) fiber. There are several problems with such filter media. For example, for glass fiber filter media, adhering fibrils are present in the filter media and self-generated during folding. These glass fibrils fall off the filter media and enter the turbine and adhere to the fan. When fine particles enter the turbine, the thermal efficiency of the turbine decreases, and therefore there is a need for a filter medium for intake air that has no self-dusting and higher particle collection performance.

Further, the collected dust causes clogging of the filter, and the pressure loss increases with the operation of the gas turbine. Washing with water or the like is effective for regenerating the filter medium that has become clogged. However, since the filter medium obtained by electretizing PP fibers is inferior in water resistance, there is a problem that the performance is greatly lowered when washed.
Various nonwoven fabrics have been proposed as materials for air filters or liquid filters for removing dust. Particularly in recent years, a thermocompression type long fiber nonwoven fabric having excellent rigidity has been suitably used as a pleated filter medium. When a pleated filter medium is used, it is possible to reduce the filtration wind speed because the filtration area can be widened, and there is an advantage that the dust collecting ability can be improved and the mechanical pressure loss can be reduced.

  For example, Patent Document 1 proposes an intake filter medium for a turbine in which a polytetrafluoroethylene porous membrane and a nonwoven fabric are laminated. According to this technique, a polytetrafluoroethylene porous membrane does not contaminate the turbine, has a high particle collection efficiency, has a low pressure loss, and can be regenerated while suppressing deterioration in performance by cleaning. Although a filter medium is provided, when a polytetrafluoroethylene porous membrane is used, the pressure loss is 100 Pa or more, and the air permeability is inferior. I can't.

  Further, Patent Document 2 proposes a filter nonwoven fabric in which a plurality of nonwoven fabrics are laminated. According to this technique, it is easy to produce a non-woven fabric for a filter having a high basis weight, and it is possible to obtain a non-woven fabric for a filter excellent in air permeability. However, the nonwoven fabric proposed in this technology is a laminate of a nonwoven fabric having a fiber diameter of 7 to 20 μm and a nonwoven fabric having a fiber diameter of 20 to 50 μm. It was not enough to collect the dust.

  On the other hand, in order to improve the dust collection performance of the filter nonwoven fabric, various filter nonwoven fabrics containing ultrafine fibers have been proposed.

  For example, Patent Document 3 proposes a non-woven fabric for a filter which is a laminate of a low-melting point nonwoven fabric and a non-woven fabric containing ultrafine fibers and is integrated by melting the low-melting point nonwoven fabric. According to the technology, it is possible to make a non-woven fabric without melting the ultrafine fibers, and thereby the inter-fiber voids inside the non-woven fabric can be held in a fine state, so that a non-woven fabric with excellent dust collection performance can be obtained. It is possible to manufacture. However, in this technique, since the ultrafine fibers do not contribute to the integration of the nonwoven fabric, there is a problem that the ultrafine fiber portion is easily dropped from the nonwoven fabric, and further, the constituent ratio of the ultrafine fibers cannot be increased. Furthermore, the ultrafine fiber in the technology is substantially introduced from a split-type non-woven fabric of the ultrafine fiber expression type, and high pressure liquid flow treatment, needle punch processing, or buckling treatment is performed for the ultrafine fiber expression. It was necessary and it was not excellent in productivity.

Further, Patent Document 4 proposes a non-woven fabric for a filter having a basis weight of 10 to 50 g / m ^{2 made} of an ultrafine fiber non-woven fabric having a fiber diameter of 1 to 6 μm and a long-fiber non-woven fabric having a fiber diameter of 10 to 30 μm. According to this technology, it is possible to propose a non-woven fabric with less powder leakage when extracting coffee powder or the like. However, since the basis weight of the nonwoven fabric provided by this technique is about 10 to 50 g / m ^2, it does not have sufficient strength to be used as an industrial filter material. Further, in this technique, it is necessary to coat the opening on the surface of the long-fiber nonwoven fabric with ultrafine fibers, which is a complicated manufacturing method.

Patent Document 5 discloses a laminated nonwoven fabric in which thermoplastic synthetic long fiber layers having a fiber diameter of 7 to 20 μm are upper and lower layers, thermoplastic synthetic fine fibers having a fiber diameter of 5 μm or less are intermediate layers, and the layers are integrated by pressure bonding. , The fine fibers enter at least one surface of the long fiber layer with an entry index of 0.36 or more, and have a structure in which long fibers are bonded, embedded or entangled and mixed, and the basis weight of the laminated nonwoven fabric is 10 to 250 g / m A non-woven fabric characterized by having a bulk density of ² or less and a bulk density of 0.20 g / cm ³ or more has been proposed. According to the technique, if the penetration index is 0.36 or more, a high-strength nonwoven fabric can be obtained. However, in such a structure, the ultrafine fibers are clogged in the long fiber layer, which is preferably used as a filter medium. There was a problem that could not be done.
JP 2002-346319 A JP 2004-124317 A Japanese Patent Laid-Open No. 2001-248056 JP 2004-154760 A Reissue WO 2004/094136

  In view of the above-mentioned problems of the prior art, the present invention provides a non-woven fabric for a filter that is excellent in mechanical strength and dimensional stability and excellent in dust collection performance and air permeability.

The present invention employs the following means in order to solve such problems.
That is,
(1) An ultrafine fiber assembly composed of a polyester fiber comprising polybutylene terephthalate or polytrimethylene terephthalate having an average fiber diameter of 1 to 8 μm, and a core component having an average fiber diameter of 10 to 30 μm containing polyethylene terephthalate, A continuous fiber nonwoven fabric comprising core-sheath fibers comprising a copolyester having a melting point lower than that of the core component is laminated and integrated in the sheath component, and the air flow rate of the laminated nonwoven fabric is 5 to 100 cc / cm ^2. / sec der is, the intake filter nonwoven fabric collection efficiency of polystyrene dust particle size 0.3~0.5μm is characterized 40-100% der Rukoto.

( 2 ) A nonwoven fabric obtained by laminating and integrating an ultrafine fiber assembly composed of fibers having an average fiber diameter of 1 to 8 μm and a long fiber nonwoven fabric composed of core-sheath fibers having an average fiber diameter of 10 to 30 μm, The sheath component of the ultra-fine fiber aggregate fiber and the core-sheath fiber of the long-fiber nonwoven fabric both comprises polybutylene terephthalate or polytrimethylene terephthalate, and the core component of the core-sheath fiber includes polyethylene terephthalate. A filter nonwoven fabric for air intake, characterized in that

( 3 ) The part which laminated | stacked and integrated the said ultrafine fiber assembly and the said long fiber nonwoven fabric has a partial thermocompression bonding part, and the crimping | compression-bonding area rate of this partial thermocompression bonding is 3 to 50% The filter nonwoven fabric for air intake according to any one of (1) or ( 2 ), which is characterized.

( 4 ) The basis weight of the laminated and integrated nonwoven fabric is 60 to 300 g / m ² , and the weight ratio of the ultrafine fiber aggregate is 3 to 60% of the total (1 ) To ( 3 ) The air filter nonwoven fabric for intake according to any one of the above.

( 5 ) The filter nonwoven fabric for intake air according to any one of (1) to ( 4 ), which is processed into a pleated shape.

  ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric for turbine inlet filters excellent in mechanical strength and thermal stability and excellent in the dust collection performance can be provided.

In the first aspect of the present invention, an ultrafine fiber assembly made of polyester fibers having an average fiber diameter of 1 to 8 μm and a long fiber nonwoven fabric made of polyester fibers having an average fiber diameter of 10 to 30 μm are laminated and integrated, An air filter nonwoven fabric, wherein the laminated nonwoven fabric has an air permeability of 5 to 100 cc / cm ² / sec.

  In the second aspect of the present invention, an ultrafine fiber assembly composed of fibers having an average fiber diameter of 1 to 8 μm and a long fiber nonwoven fabric composed of core-sheath fibers having an average fiber diameter of 10 to 30 μm are laminated and integrated. And the sheath component of the core-sheath fiber of the long-fiber nonwoven fabric comprises polybutylene terephthalate or polytrimethylene terephthalate, and the core-sheath long fiber A filter nonwoven fabric for air intake, wherein the core component comprises polyethylene terephthalate.

The ultrafine fiber assembly in the present invention is represented by a method in which a molten polymer is extruded from a die, and the molten polymer is stretched while being blown with a heated high-speed gas fluid or the like to form ultrafine fibers and collected to form a sheet. A melt blown nonwoven fabric produced by the so-called melt blow method is preferred.
The average fiber diameter of the fibers constituting the ultrafine fiber assembly needs to be 1 to 8 μm. The average fiber diameter is more preferably 2 μm or more and 7 μm or less. When the average fiber diameter is smaller than 1 μm, when the polymer is stretched to form ultrafine fibers, the fibers are easily cut and a lump polymer may be mixed, which is not preferable. Furthermore, there is a tendency that the air permeability of the nonwoven fabric is lowered, which is not preferable. When the average fiber diameter is more than 8 μm, the fiber becomes too thick, which is not preferable because the dust collection performance tends to be lowered. In addition, the average fiber diameter here refers to a total of 100 fibers, 10 of which are randomly sampled from a nonwoven fabric, photographed 500 to 3000 times with a scanning electron microscope or the like, and 10 from each sample. It is obtained by measuring the diameter and rounding off the first decimal place of the average value.

  Moreover, the fiber which comprises the ultrafine fiber assembly in this invention consists of a polyester-type fiber. Among these, at least one of polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate is included, and any of these is preferably a main component. Specifically, at least any one of polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. preferable. Among them, a melt blown nonwoven fabric made of polybutylene terephthalate or polypropylene terephthalate is preferable as the ultrafine fiber aggregate in the present invention because it has a relatively high melting point and is excellent in heat resistance and also has excellent dimensional stability due to heat. Particularly preferred is a melt blown nonwoven fabric made of polybutylene terephthalate from the viewpoint of high dimensional stability due to heat and less contamination of the die during injection of molten polymer.

  Furthermore, the raw material resin of the fibers constituting the ultrafine fiber aggregate is provided with a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a hydrophilic agent, etc., as long as the effects of the present invention are not impaired. It may be added. Moreover, as long as the original function is not impaired, it may contain a very small amount of a copolymer component.

  Further, the long-fiber nonwoven fabric used in the present invention is obtained by extruding a molten polymer from a base, and drawing and stretching it with a high-speed suction gas, etc. A spunbonded nonwoven fabric produced by a so-called spunbond method represented by a method of forming a sheet by entanglement or the like is preferable. The average fiber diameter of the fibers constituting the long fiber nonwoven fabric needs to be 10 to 30 μm. Furthermore, the average fiber diameter is more preferably 12 μm or more and 25 μm or less. When the average fiber diameter is smaller than 10 μm, the air permeability of the nonwoven fabric is lowered and the rigidity of the nonwoven fabric tends to be lowered, which is not preferable. Moreover, it is an unfavorable direction from the viewpoint of production stability because yarn breakage tends to occur during the production of a spunbonded nonwoven fabric. When the average fiber diameter is larger than 30 μm, yarn breakage is liable to occur due to poor cooling of the yarn during production of the spunbonded nonwoven fabric, which is not preferable from the viewpoint of production stability. In addition, the average fiber diameter here refers to a total of 100 fibers, 10 of which are randomly sampled from a nonwoven fabric, photographed 500 to 3000 times with a scanning electron microscope or the like, and 10 from each sample. It is obtained by measuring the diameter and rounding off the first decimal place of the average value.

  Moreover, it is preferable that the said long fiber nonwoven fabric is a polyester-type nonwoven fabric. Polyester-based nonwoven fabrics are preferable because they have a high melting point and are excellent in heat resistance and also in rigidity. The polyester-based non-woven fabric is a spunbonded non-woven fabric made only of polyethylene terephthalate or a core-sheathed spunbonded non-woven fabric in which the core part contains polyethylene terephthalate and the sheath part contains a copolyester having a lower melting point than the polymer of the core part. However, this is a preferable form from the viewpoint of strength and rigidity of the nonwoven fabric. The copolymer polyester preferably has a melting point of 15 ° C. or more lower than that of polyethylene terephthalate contained in the core, and isophthalic acid and adipic acid are preferable as the copolymer component.

  The core-sheath-type spunbonded nonwoven fabric comprises core-sheath fibers, the core component includes polyethylene terephthalate, the sheath component includes polybutylene terephthalate or polytrimethylene terephthalate, and the ultrafine fiber assembly Are similar in structure, and the most preferable form is that the sheath component of the core-sheath-type spunbonded nonwoven fabric and the fibers constituting the ultrafine fiber assembly are made of the same polymer. When such a core-sheath fiber is employed, polyethylene terephthalate, which is the core component, has a higher melting point than the polymer constituting the sheath component, so it is less susceptible to damage during thermocompression bonding with the ultrafine fiber assembly, and the strength and rigidity of the nonwoven fabric are reduced. It tends to improve. Furthermore, when the polymer of the sheath component is structurally similar to the ultrafine fiber aggregate, or in particular, the same polymer, the compatibility of the ultrafine fiber aggregate and the long-fiber nonwoven fabric is improved, and a strong integral during thermocompression bonding It becomes possible to make it a structure.

  In the present invention, a melt blown nonwoven fabric made of polybutylene terephthalate and a spunbonded nonwoven fabric made of a core-sheath fiber having a sheath component of polybutylene terephthalate are laminated and integrated.

Although the use application of the filter nonwoven fabric for air intake of the present invention is not limited at all, since it is excellent in mechanical strength and dimensional stability and excellent in dust collection performance, as a pleated cylindrical unit, gas It is used for intake filter applications such as turbines.
The filter using the non-woven fabric formed by laminating and integrating according to the present invention is particularly suitable for an intake filter that sucks outdoor air. There are various foreign substances in the outdoor atmosphere, and it is difficult to suck clean air. In particular, dust may be sucked in desert areas, salt in coastal areas, and leaves and insects in forest areas. When using a filter comprising a melt blown nonwoven fabric alone in such an environment, it is necessary to install a coarse dust filter in front of the melt blown nonwoven fabric filter in order to prevent damage to the melt blown nonwoven fabric, which requires installation space and costs. However, by using the non-woven fabric that is laminated and integrated according to the present invention, it is not necessary to install a coarse filter, and the equipment can be downsized and the cost can be reduced. In addition, if it is used as a filter unit processed into a pleated shape, dust attached to the surface spunbond nonwoven fabric can be easily removed by a pulse jet, and it can be used as a filter with a long filter life. .

  In the present invention, the core-sheath type means that the sheath component is coated concentrically or eccentrically around the core component, and the sheath component is arranged in a multi-leaf shape around the core component. Is a preferred form. The various shapes refer to, for example, the shapes shown in FIG. Most preferred are concentric core-sheath fibers from the viewpoint of production simplicity. The weight ratio of the core: sheath is not particularly limited, but is preferably in the range of 30:70 to 95: 5, and more preferably in the range of 40:60 to 90:10.

  Further, the cross-sectional shape of the fibers constituting the long-fiber nonwoven fabric is not limited at all, but it is circular, hollow round, elliptical, flat, or deformed, such as X-shaped or Y-shaped, polygonal, multileaf A mold or the like is a preferred form. The fiber diameter of the non-circular fiber may be a circumscribed circle and an inscribed circle with respect to the fiber cross section, and the average value of the diameters may be the fiber diameter.

  Furthermore, the raw material resin for the spunbond nonwoven fabric according to the present invention is added with a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a hydrophilic agent, etc., as long as the effects of the present invention are not impaired. May be. Moreover, as long as the original function is not impaired, it may contain a very small amount of a copolymer component.

  In the present invention, an ultrafine fiber assembly and a long-fiber nonwoven fabric are laminated and integrated. First, lamination is performed, and then integration is performed.

  The method for laminating the ultrafine fiber assembly and the long fiber nonwoven fabric in the present invention is not limited at all. A method of laminating after the production of ultrafine fiber aggregates and long fiber nonwoven fabrics, a method of laminating ultrafine fiber aggregates by spraying yarns on the once produced long fiber nonwoven fabrics by a melt blow method, and ultrafine fibers once produced It can be carried out by a method in which yarns are sprayed onto the aggregate by the spunbond method to laminate a long-fiber nonwoven fabric, and further a combination thereof.

  The integration of the ultrafine fiber assembly and the long fiber nonwoven fabric in the present invention is preferably performed by partial thermocompression bonding. It is also a preferred method to perform partial thermocompression bonding after mechanical entanglement by water jet punching or needle punching. The method of partially thermocompression bonding is not particularly limited, but bonding with a pair of hot embossing rolls or bonding with an ultrasonic oscillator and an embossing roll is preferable. The temperature of heat bonding with the hot embossing roll is preferably 5 to 50 ° C., more preferably 10 to 40 ° C. lower than the melting point of the fibers constituting the ultrafine fiber aggregate. When the temperature of heat bonding by the hot embossing roll is lower than the melting point of the fibers constituting the ultrafine fiber aggregate by less than 5 ° C, the resin melts severely, the sheet is taken on the embossing roll, and roll contamination occurs. In addition to the fact that the sheet becomes stiff, roll winding often occurs and stable production becomes impossible. Further, when the temperature is lower than the melting point of the fibers constituting the ultrafine fiber aggregate by more than 50 ° C., the resin is insufficiently fused, and the integrated nonwoven fabric tends to be weak in physical properties. .

  When the partial thermocompression bonding is performed, the pressure-bonding area ratio is preferably 3 to 50% with respect to the total area of the nonwoven fabric. More preferably, it is 5 to 40%. When the thermocompression bonding rate is less than 3%, the laminated integration of the ultrafine fiber aggregate and the long fiber nonwoven fabric is insufficient, and the layers of the nonwoven fabric tend to peel off or become lower in strength. When the thermocompression bonding rate exceeds 50%, the number of fibers that are melt-deformed by thermocompression bonding increases, the gap between the fibers decreases, and the dust collection performance tends to decrease, which is not preferable. In addition, the pressure-bonding area ratio of the partial thermocompression bonding is a ratio of the area of the pressure-bonding portion where the ultrafine fiber aggregate and the long-fiber non-woven fabric are laminated and integrated to the total contact area of both non-woven fabrics. This does not include the area of thermocompression performed when manufacturing.

  Furthermore, the laminated state of the ultrafine fiber assembly (M) and the long fiber nonwoven fabric (S) in the present invention is not limited at all, but SM laminated, SMS laminated, SMMS laminated, etc. are preferable forms (for example, The SMS laminate refers to a laminate in which one layer of ultrafine fiber assemblies is laminated in a state of being sandwiched between one layer of long fiber nonwoven fabric from both sides. When a plurality of ultrafine fiber aggregates or long-fiber nonwoven fabrics are laminated, there is no problem as long as the average fiber diameter and fiber shape of each constituent fiber are different as long as they are within the above-described average fiber diameter and fiber shape range.

In the first aspect of the present invention, the air permeability of the non-woven fabric that is laminated and integrated needs to be 5 to 100 cc / cm ² / sec. More preferably, it is 10 cc / cm ² / sec or more and 80 cc / cm ² / sec or less. When the air flow rate is lower than 5 cc / cm ² / sec, since there is no air permeability, the pressure loss becomes high, a load is applied, and the filter is easily clogged. On the other hand, if the air flow rate is greater than 100 cc / cm ² / sec, sufficient collection performance cannot be obtained and dust is sucked, which is not preferable.
Also in the second aspect of the present invention, it is preferable that the air permeability of the non-woven fabric laminated and integrated is 5 to 100 cc / cm ² / sec. More preferably, it is 10 cc / cm ² / sec or more and 80 cc / cm ² / sec or less.

In the present invention, the basis weight of the nonwoven fabric laminated and integrated is preferably in the range of 60 to 300 g / m ² . When the basis weight is less than 60 g / m ² , the strength and rigidity of the nonwoven fabric may be insufficient, which is not preferable. When the weight per unit area exceeds 300 g / m ² , the strength and rigidity of the nonwoven fabric are sufficient, but the air permeability tends to decrease, and further, it is not preferable in terms of cost. The more preferable basis weight of the laminated and integrated nonwoven fabric is 80 g / m ² or more and 270 g / m ² or less. The basis weight here refers to 5.2 of JIS L1906 (2000 edition), three samples were taken and each weight was measured, and the average value of the obtained values was converted per unit area, and the number after the decimal point It is calculated by rounding off the first place.

  Moreover, 3 to 60% is preferable, and, as for the weight ratio of the said ultrafine fiber assembly which occupies for the said nonwoven fabric formed by lamination | stacking integration, More preferably, it is 5 to 50%. When the weight ratio of the ultrafine fiber aggregate is less than 3%, the dust collection performance tends to be too low, which is not preferable. When the weight ratio of the ultrafine fiber aggregate exceeds 60%, the dust collection performance is not preferable. However, the air permeability tends to be lowered, and it is not preferable from the viewpoint of cost.

  In the nonwoven fabric obtained by laminating and integrating in the present invention, an antifungal agent, an antibacterial agent, a flame retardant, a hydrophilic agent, a pigment, a dye, and the like are partially or wholly provided within a range that does not impair the effects of the present invention. Also good.

  Moreover, the nonwoven fabric for filters in the present invention has a particle size of 0.3 to 0 in the evaluation of the dust collection performance described in the examples below, or in the evaluation of the dust collection performance capable of obtaining an equivalent result. It is preferable that the collection efficiency of .5 μm polystyrene dust is 40 to 100%. A more preferable collection efficiency is 55 to 100%. When the collection efficiency is less than 40%, there is a lot of dust leakage, which is not preferable.

  Since the nonwoven fabric for filters of the present invention is excellent in rigidity, it can be easily processed into a pleated shape, and is excellent in pleated form retention. Therefore, it is a preferable form to be used as a pleated filter.

  The use of the non-woven fabric for filter of the present invention is not limited at all, but it is preferably used as an industrial intake filter because of its excellent mechanical strength and dimensional stability and excellent dust collection performance. . Particularly preferably, the pleated cylindrical unit is used for a turbine intake filter. Among them, in particular, in an air filter for a gas turbine installed outdoors, the non-woven fabric of the present invention having excellent strength is preferable because the dust accumulated on the filter surface during use is subjected to a removal process using backwash air.

  EXAMPLES Hereinafter, although this invention is concretely demonstrated based on an Example, this invention is not limited by these Examples. In addition, each characteristic value of an above-described nonwoven fabric and each characteristic value in the following Example are measured with the following method.

(1) Melting point (° C)
Using a differential scanning calorimeter DSC-2 manufactured by Perkin Elma Co., Ltd., measurement was performed under the condition of a temperature rise temperature of 20 ° C./min, and the temperature giving an extreme value in the obtained melting endotherm curve was defined as the melting point. Each sample was measured three times, and the average value was taken as the melting point of each sample.

(2) Melt viscosity (poise)
The raw material resin was dried to a moisture content of 80 ppm by weight or less, and was measured three times under a nitrogen atmosphere under the conditions of a measurement temperature of 280 ° C. and a strain rate of 6080 sec ⁻¹ using a Toyo Seiki Capillograph 1B. It was set as melt viscosity.

(3) Fiber diameter (μm)
Ten small sample pieces were randomly collected from the ultrafine fiber assembly and the long fiber non-woven fabric constituting the non-woven fabric, photographed 500 to 3000 times with a scanning electron microscope, and 10 from each sample, a total of 100 samples. The fiber diameter was measured and calculated by rounding off the first decimal place of the average value.

(4) Weight per unit (g / m ² )
In accordance with JIS L1906 (2000 edition) 5.2, three samples of 50 cm in the vertical direction and 50 cm in the horizontal direction were taken, the weight of each sample was measured, and the average value of the obtained values per unit area Converted to rounded off to the first decimal place.

(5) Tensile strength (N / 5cm)
In accordance with JIS L1906 (2000 version) 5.3.1, a tensile test was performed on three samples in both the longitudinal and lateral directions under the conditions of a sample size of 5 cm × 30 cm, a gripping interval of 20 cm, and a tensile speed of 10 cm / min. The maximum strength when the sample was pulled until it broke was taken as the tensile strength, and the average value in the longitudinal and lateral directions of the sheet was calculated by rounding off the first decimal place.

(6) Pleating processability A sample having a width of 1 m and a length of 300 m was pleated with a rotary pleating machine so as to have a peak height of 2.5 cm, and evaluated according to the following criteria.
○: The pleat is uniform and there is no problem in processing.
Δ: Pleated is slightly non-uniform.
X: The pleat is uneven and there is a problem in processing.

(7) Aeration rate (cc / cm ² / sec)
The air permeability of the nonwoven fabric for filters in the present invention was measured by the following method.
In accordance with 8.27.1 of JIS L1096 (2000 edition), however, five samples measuring 20 cm in length and 20 cm in width were taken from any part of the nonwoven fabric, and air was sucked at a pressure of 125 Pa using a Frazier type tester. The amount of air that passed through was taken as the amount of ventilation. The aeration amount was calculated by rounding off the first decimal place of the average value of the obtained values.

(8) Dust collection performance (%)
The dust collection performance was measured by the following method.

Three samples of 15 cm × 15 cm were collected from an arbitrary portion of the nonwoven fabric, and the collection performance of each sample was measured with the collection performance measuring device shown in FIG. This collection performance measuring apparatus has a configuration in which a dust storage box 2 is connected to the upstream side of a sample holder 1 for setting a measurement sample M, and a flow meter 3, a flow rate adjusting valve 4 and a blower 5 are connected to the downstream side. Yes. Further, the particle counter 6 is connected to the sample holder 1, and the number of dusts on the upstream side and the number of dusts on the downstream side of the measurement sample M can be measured via the switching cock 7. In measuring the collection efficiency, a 10% by weight polystyrene 0.309U solution (manufactured by Nacalai Tech) is diluted 200 times with distilled water and filled in the dust storage box 2. Next, the sample M is set in the holder 1, and the air volume is adjusted by the flow rate adjusting valve 4 so that the filter passing speed is 3.0 m / min, and the dust concentration is 20,000 to 70,000 pieces / (2.83 × 10 ^-4 m ² (0.01 ft ² )), the dust number D2 upstream and the dust number D1 downstream of the sample M are set to a particle size of 0. 0 with a particle counter 6 (manufactured by Lion, KC-01D). Each of the ranges of 3 to 0.5 μm was measured, and the collection efficiency (%) was obtained by rounding off the first decimal place of the numerical value obtained by the following formula.
Collection efficiency (%) = [1- (D1 / D2)] × 100
Here, D1: downstream dust count (total of 3 times)
D2: Number of upstream dust (total of 3 times).

Production Example 1
Polybutylene terephthalate (PBT) having a melt viscosity of 390 poise and a melting point of 221 ° C. dried to a moisture content of 80 ppm by weight or less was melted at 280 ° C., and the average fiber diameter was 7 μm under the conditions of the die temperature of 280 ° C. and the heated air temperature of 285 ° C. The amount of hot air and the cooling conditions were adjusted so that a melt blown nonwoven fabric with a basis weight of 40 g / m ² was produced.

Production Example 2
A melt blown nonwoven fabric was produced under the same conditions as in Production Example 1 except that the basis weight was 30 g / m ² .

Production Example 3
A melt blown nonwoven fabric with a basis weight of 30 g / m ² was produced under the same conditions as in Production Example 1 except that the amount of hot air and the cooling conditions were adjusted so that the average fiber diameter was 2 μm.

Production Example 4
Polyethylene terephthalate (PET) having a melt viscosity of 800 poise and a melting point of 260 ° C. dried to a moisture content of 80 ppm by weight and a melt viscosity of 420 poise dried to a moisture content of 80 ppm by weight and an isophthalic acid copolymerization ratio of 11 mol% having a melting point of 230 ° C. Copolyester (CO-PET) is melted at 295 ° C. and 280 ° C., respectively, with polyethylene terephthalate as a core component and copolymer polyester as a sheath component, a base temperature of 300 ° C., and a weight ratio of core: sheath = 80: 20. After spinning from the pores, the web spun by an ejector at a spinning speed of 4400 m / min and collected on a moving net conveyor is heated with an embossing roll and a flat roll having a convex area of 16%. 140 ° C., and thermocompression bonding under the conditions of a linear pressure 60 kg / cm, fiber diameter 12 [mu] m, basis weight 50 g / m It was prepared spunbonded nonwoven fabric.

Production Example 5
A polyethylene terephthalate (PET) having a melt viscosity of 800 poise and a melting point of 260 ° C. dried to a moisture content of 80 ppm by weight and a polybutylene terephthalate (PBT) described in Production Example 1 dried to a moisture content of 80 ppm by weight are 295 ° C. And melted at 280 ° C., using polyethylene terephthalate as the core component and polybutylene terephthalate as the sheath component, spinning from the pores at a base temperature of 300 ° C. and a weight ratio of core: sheath = 80: 20, and spinning speed of 4400 m by ejector The web obtained by spinning on a moving net conveyor is thermocompression bonded with an embossing roll and a flat roll with a convex area of 16% under the conditions of a temperature of 140 ° C. and a linear pressure of 60 kg / cm. A spunbonded nonwoven fabric having a fiber diameter of 13 μm and a basis weight of 50 g / m ² was produced.

Production Example 6
A spunbonded nonwoven fabric was produced under the same conditions as in Production Example 5 except that the basis weight was 100 g / m ² .

Example 1
The polyester spunbonded nonwoven fabric (PET / CO-PET-SB: S) obtained in Production Example 4 is laminated on both sides of the polybutylene terephthalate meltblown nonwoven fabric (PBT-MB: M) obtained in Production Example 1. (SMS lamination), an ultrasonic oscillator and an embossing roll with a pressure bonding rate of 10% were used and integrated by ultrasonic bonding.

Example 2
The polyester spunbond nonwoven fabric (PET / CO-PET-SB: S) obtained in Production Example 4 is laminated on both sides of the polybutylene terephthalate melt blown nonwoven fabric (PBT-MB: M) obtained in Production Example 2. (SMS lamination) An embossing roll having a pressure bonding ratio of 16% was used and integrated under conditions of a temperature of 185 ° C. and a linear pressure of 60 kg / cm.

Example 3
The spunbonded nonwoven fabric (PET / PBT-SB: S) obtained in Production Example 5 is laminated on both sides of the polybutylene terephthalate melt-blown nonwoven fabric (PBT-MB: M) obtained in Production Example 3 (SMS lamination). Then, an embossing roll having a pressure bonding ratio of 16% was used and integrated under conditions of a temperature of 190 ° C. and a linear pressure of 60 kg / cm.

Example 4
The spunbonded nonwoven fabric (PET / PBT-SB: S) obtained in Production Example 6 is laminated on one side of the polybutylene terephthalate melt blown nonwoven fabric (PBT-MB: M) obtained in Production Example 3 (SM lamination). Using an ultrasonic oscillator and an embossing roll with a pressure bonding rate of 10%, they were integrated by ultrasonic bonding.

  The properties of the obtained nonwoven fabric are as shown in Table 3, but the nonwoven fabrics of Examples 1, 2, 3, and 4 were all excellent in air permeability and had no problem with pleat processability. Also, the dust collection efficiency was all good at 50% or more.

Comparative Example 1
A melt blown nonwoven fabric (PBT-MB) was produced under the same conditions as in Production Example 3 except that the basis weight was 60 g / m ² .

  The properties of the obtained nonwoven fabric are as shown in Table 3, but the melt-blown nonwoven fabric of Comparative Example 1 was excellent in dust collection efficiency, but could not be pleated.

  The non-woven fabric for intake air according to the present invention is excellent in air permeability and dust collection performance, so that it can be suitably used particularly as an industrial intake filter, particularly as a gas turbine intake filter.

It is the schematic of a collection performance measuring device. It is a figure which shows the example of multileaf shape.

Explanation of symbols

1 Sample holder 2 Dust storage box 3 Flow meter 4 Flow control valve 5 Blower 6 Particle counter 7 Switching cock 8 Core component in core-sheath fiber 9 Sheath component M in core-sheath fiber Measurement sample

Claims (5)

An ultrafine fiber assembly made of polyester fibers containing polybutylene terephthalate or polytrimethylene terephthalate having an average fiber diameter of 1 to 8 μm, a core component having an average fiber diameter of 10 to 30 μm , containing polyethylene terephthalate, and a sheath component A long-fiber nonwoven fabric composed of core-sheath fibers comprising a copolyester having a melting point lower than that of the core component is laminated and integrated, and the air flow rate of the laminated and integrated nonwoven fabric is 5 to 100 cc / cm ² / sec. Ah is, the intake filter nonwoven fabric collection efficiency of polystyrene dust particle size 0.3~0.5μm is characterized 40-100% der Rukoto. A non-woven fabric obtained by laminating and integrating a very fine fiber assembly made of fibers having an average fiber diameter of 1 to 8 μm and a long fiber non-woven fabric made of core-sheath fibers having an average fiber diameter of 10 to 30 μm, The core component of the body and the sheath component of the core-sheath fiber of the non-woven fabric comprise polybutylene terephthalate or polytrimethylene terephthalate, and the core component of the core-sheath fiber comprises polyethylene terephthalate. Filter nonwoven fabric for air intake. A portion where the ultrafine fiber aggregate and the long fiber nonwoven fabric are laminated and integrated has a partial thermocompression bonding portion, and the pressure bonding area ratio of the partial thermocompression bonding is 3 to 50%. The filter nonwoven fabric for air intake according to claim 1 or 2 . Basis weight of the nonwoven fabric formed by the integral lamination is the 60~300g / m ^2, claim 1-3 where the weight ratio of these said ultrafine fibrous aggregate, characterized in that 3 to 60% of the total The filter nonwoven fabric for inhalation in any one of. The filter nonwoven fabric for air intake according to any one of claims 1 to 4 , wherein the filter nonwoven fabric for intake air is processed into a pleated shape.

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