JP2007237167A - Nonwoven fabric for filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric for a filter excellent in dust removal ability of powder dust and excellent in mechanical properties and rigidity. <P>SOLUTION: The nonwoven fabric for a filter is characterized in comprising polyester-based continuous filaments containing 0.1-5.0 wt.% aliphatic bisamide and/or alkyl-substituted type aliphatic monoamide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-woven fabric for a filter which is excellent in dust wiping-out property and further excellent in mechanical properties and rigidity.

  Conventionally, various nonwoven fabrics have been proposed as materials for air filters or liquid filters for removing dust. Particularly in recent years, non-woven fabric having excellent rigidity has been processed into a pleated shape and is suitably used as a filter. Among these, long fiber nonwoven fabrics made of long fibers and integrated by thermocompression bonding are preferably used because they are composed of long fibers and are less likely to cause fuzz and have high rigidity. When a pleated filter material is used, it is possible to reduce a filtration wind speed because a large filtration area can be obtained, and there is an advantage that it is possible to improve dust collecting ability and reduce mechanical pressure loss.

  However, many conventional thermocompression-bonding type nonwoven fabrics have sufficient dust collection performance, but the dust-off performance is insufficient. That is, in these nonwoven fabrics, general synthetic fibers form three-dimensionally intersecting spaces to create voids, and dust is collected in these voids. Therefore, fine dust is collected and then removed. The nonwoven fabric was clogged, and the filter life was not sufficient.

  For example, Patent Document 1 proposes a filter nonwoven fabric in which a plurality of polyester nonwoven fabrics are laminated. According to this technique, it is considered that a non-woven fabric for a filter having a high basis weight can be easily produced, and a non-woven fabric for a filter excellent in air permeability can be obtained. However, the nonwoven fabric proposed in this technique is made of a general polyester fiber, and no technique for improving dust wiping-off property has been proposed.

  Patent Document 2 proposes a composite long-fiber nonwoven fabric for filters made of irregularly shaped fibers. According to this technology, it is possible to improve the mechanical properties and dimensional stability of the nonwoven fabric for filters, but, as in Patent Document 1, it does not give any suggestion about the improvement of dust wiping out property. It was.

  Further, Patent Document 3 proposes a non-woven fabric for a filter formed by fusing the fibers of the surface layer portion of a long-fiber non-woven fabric partially heat-welded. According to this technology, it is possible to obtain a non-woven fabric for a filter with little fluff generation even by long-term use. Moreover, since the fibers of the nonwoven fabric surface layer are fused, it is presumed that the dusting-off property is improved. However, generally, when the fusion part of the constituent fibers of the nonwoven fabric increases and the surface area of the fiber decreases, the contact area with the dust decreases and the collection performance decreases. In addition, when the fibers are fused and the gap between the fibers is reduced, there is a problem that the pressure loss increases, and the collection performance and the pressure loss are not excellent. Furthermore, it was necessary to process the partially heat-bonded long-fiber nonwoven fabric once produced with a hot roll, and the productivity was not high.

Furthermore, Patent Document 4 proposes a non-woven fabric for air filter in which the depth of the depression on the surface of the polyester-based non-woven fabric is set to a specific value. According to the technique, the dust-off property from the nonwoven fabric surface can be improved by reducing the unevenness of the nonwoven fabric surface. However, in this technique, only by reducing the depth of the depression on the surface of the nonwoven fabric, it is intended to improve the dust removal performance, and the performance of the removal is not always sufficient. There was no suggestion about the dust removal performance.
JP 2004-124317 A JP 2001-276529 A JP 2005-7268 A Japanese Patent No. 3339283

  The present invention relates to a non-woven fabric for a filter which is excellent in dust wiping-out property and further excellent in mechanical properties and rigidity.

The present invention employs the following means in order to solve such problems.
That is,
(1) A nonwoven fabric for a filter comprising a polyester filament containing 0.1 to 5.0 wt% of an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide.

  (2) A nonwoven fabric for a filter comprising a polyester-based sheath-core filament containing 0.1 to 5.0 wt% of aliphatic bisamide and / or alkyl-substituted aliphatic monoamide as a sheath component.

  (3) The filter nonwoven fabric according to (1) or (2) above, wherein the filter nonwoven fabric is integrated by partial thermocompression bonding, and the pressure-bonding area ratio of the partial thermocompression bonding is 5 to 50%.

  (4) The nonwoven fabric for filters according to any one of (1) to (3), wherein the bending resistance of the nonwoven fabric for filters is 2 to 80 mN.

  (5) The nonwoven fabric for a filter according to any one of (1) to (4), which is used for a pleated filter.

  ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric for filters which is excellent in the dusting-off property, and also excellent in a mechanical characteristic and rigidity can be provided.

  The non-woven fabric for filter in the present invention is made of a polyester filament containing 0.1 to 5.0 wt% of aliphatic bisamide and / or alkyl-substituted aliphatic monoamide.

  The polyester-based resin constituting the filament is not particularly limited, and a known polyester-based resin such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polylactic acid, a mixture thereof or a copolyester can be used.

  As will be described later, the cross-sectional shape of the filament is not particularly limited, and may be a composite filament such as a core-sheath type, a sea-island type, or a side-by-side type. In the case of a composite filament, it is preferable that any component is a polyester resin.

  As the polyester filament, a core-sheath filament in which a low melting point component is arranged around a high melting point component is most preferable. Here, the content ratio of the high melting point component: low melting point component is preferably in the range of 30:70 to 95: 5, and more preferably in the range of 40:60 to 90:10. Further, as the high melting point component, those containing polyethylene terephthalate are preferable, and those containing as a main component are more preferable. Here, the content as a main component is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. The low-melting point component is preferably one containing a copolyester or polybutylene terephthalate, more preferably one containing a main component. Here, the content as a main component is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. The most preferable low melting point component is one containing a copolyester as a main component. Further, isophthalic acid and adipic acid are particularly preferred as the copolymer component of the copolymer polyester.

  The difference in melting point between the high melting point component and the low melting point component is preferably 15 ° C. or higher, and more preferably 20 ° C. or higher. The melting point of the resin in the present invention is measured using a differential scanning calorimeter under the condition of a temperature rising rate of 20 ° C./min, and is a temperature giving an extreme value in the obtained melting endothermic curve. For a resin whose melting endotherm curve does not show an extreme value in a differential scanning calorimeter, the resin is heated on a hot plate, and the temperature at which the resin is melted by microscopic observation is defined as the melting point.

  In the present invention, the core-sheath filament in which a low melting point component is arranged around a high melting point component is a core sheath filament in which the low melting point component is completely covered around the high melting point component, and further, a low melting point around the high melting point component. What forms a component intermittently is a preferable form. When the core-sheath filament is adopted, when the filament is integrated to form a nonwoven fabric, only the low melting point component that is the sheath component melts, and the high melting point component that is the core component does not melt, so it is less susceptible to thermal damage, Since integration is easy, it is preferable.

  In addition, although the cross-sectional shape of the polyester filament in the present invention is not limited at all, it is circular, hollow round, elliptical, flat, or deformed, such as X, Y, polygonal, multileaf In the case where a core-sheath filament is employed, the sheath component may be present on the outer periphery of the filament so that the sheath component can easily contribute to the integration.

The polyester filament according to the present invention contains 0.1 to 5.0 wt% of aliphatic bisamide and / or alkyl-substituted aliphatic monoamide. By containing 0.1 to 5.0 wt% of aliphatic bisamide and / or alkyl-substituted aliphatic monoamide, the polyester filament has a low frictional resistance on the fiber surface, and when used as a non-woven fabric for filters, The collected dust is easily removed from the fiber surface. A more preferable content range is 0.3 to 4.0 wt%, and a most preferable range is 0.5 to 2.0 wt%. An aliphatic bisamide or an alkyl-substituted aliphatic monoamide may be used alone, or a combination of both may be used. If the content is 0.1 wt% or more, the dust removal effect is sufficient. If content is 5.0 wt% or less, spinnability is preferable, without becoming unstable.
In addition, since the aliphatic bisamide and the alkyl-substituted aliphatic monoamide are preferably present on the surface of the filament or in the vicinity of the surface, a form in which the core-sheath filament contains them only in the sheath component is also preferable. In the present invention, the form in which the core-sheath filament is employed and the sheath component alone contains the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide does not need to be contained in the core component. And the most preferable form from the viewpoint of manufacturing cost. When an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide is contained in the sheath component, the amount of the aliphatic bisamide, the alkyl-substituted aliphatic monoamide, or both may be contained only in the sheath component resin. Good.

  The aliphatic bisamide used in the present invention is not particularly limited, and examples thereof include saturated fatty acid bisamides, unsaturated fatty acid bisamides, and aromatic fatty acid bisamides, such as methylene bis stearamide, ethylene bis stearamide, Examples thereof include ethylene bisvalmitic acid amide and ethylene bisoleic acid amide, and a plurality of these may be used in combination.

  Examples of the alkyl-substituted aliphatic monoamide used in the present invention include compounds having a structure in which an amide hydrogen such as a saturated fatty acid monoamide or an unsaturated fatty acid monoamide is substituted with an alkyl group, and N-lauryl lauric acid amide and N-palmityl Examples thereof include palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, and a plurality of these may be used in combination.

  The method of adding the aliphatic bisamide and / or the alkyl-substituted aliphatic monoamide to the resin used as a raw material for spinning is not limited at all, but a master in which the raw material resin and the substance to be added are previously heated and melt mixed. The most preferable method is to prepare a chip and add the necessary amount to the raw material resin during spinning to adjust the amount of the added substance. The polyester continuous filament may be added with a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, a hydrophilic agent, and the like as long as the effects of the present invention are not impaired.

  In the present invention, the monofilament fineness of the polyester filament is preferably in the range of 1 to 10 dtex. When the single fiber fineness of the polyester filament is less than 1 dtex, the pressure loss of the nonwoven fabric tends to be high, and further, it is not preferable from the viewpoint of production stability such that yarn breakage tends to occur during production. In addition, when the single filament fineness of the polyester filament exceeds 10 dtex, the collection performance of the nonwoven fabric tends to decrease, and it is also preferable from the viewpoint of production stability such that the filament is likely to break due to poor cooling of the filament during production. There is no direction. A more preferable fineness range is 1 to 8 dtex. In addition, the fineness here refers to a sample of 10 small pieces randomly taken from a nonwoven fabric, photographed 500 to 3000 times with a scanning electron microscope or the like, and 10 from each sample, a diameter of 100 fibers in total. The fiber diameter calculated by rounding off the first decimal place of those average values is corrected by the polymer density, and the first decimal place is rounded off.

  The nonwoven fabric for a filter of the present invention is preferably one in which a web composed of the polyester filaments is integrated by partial thermocompression bonding. The method of partially thermocompression bonding is not particularly limited, but bonding with a hot embossing roll or bonding with an ultrasonic oscillator and an embossing roll is preferable. In particular, adhesion by a hot embossing roll is most preferable from the viewpoint of improving the strength of the nonwoven fabric. The temperature of heat bonding by the hot embossing roll is preferably 5 to 70 ° C., more preferably 10 to 60 ° C. lower than the melting point of the lowest melting point polymer present on the fiber surface of the nonwoven fabric. When the temperature difference between the temperature of heat bonding by the hot embossing roll and the melting point of the polymer having the lowest melting point present on the fiber surface of the nonwoven fabric is less than 5 ° C., the heat bonding tends to be too strong, which is not preferable. When the temperature exceeds 70 ° C., thermal bonding may be insufficient, which is an undesirable direction.

  In addition, the area ratio of partial thermocompression bonding in the nonwoven fabric for filters of the present invention is the ratio of the total area of the nonwoven fabric in the thermocompression bonding portion, and 5 to 50% of the total area of the nonwoven fabric is a preferred range. . If the said crimping | compression-bonding area rate is 5% or more, since it becomes the tendency for the intensity | strength of a nonwoven fabric to fully be acquired and also the surface becomes difficult to fluff, it is preferable. If the pressure-bonding area ratio is 50% or less, the voids between the fibers are reduced, the pressure loss is increased, and the tendency of the collection performance to decrease is reduced, which is preferable. A more preferable crimping area ratio is 6 to 40%, and a most preferable crimping area ratio is 8 to 30%.

  The thermocompression bonding part forms a hollow, and is formed by fusing thermoplastic continuous filaments constituting the nonwoven fabric by heat and pressure. That is, the portion where the thermoplastic continuous filament is fused and aggregated as compared with other portions is the thermocompression bonding portion. When adhesion by a hot embossing roll is adopted as a method of thermocompression bonding, a portion where the thermoplastic continuous filaments are fused and aggregated by the convex portion of the embossing roll becomes a thermocompression bonding portion. For example, it is composed of a pair of upper and lower rolls formed with a plurality of parallel grooves arranged on the surface, and the upper roll groove and the lower roll groove intersect at a certain angle. In the case of using the embossing roll provided in the above, the thermocompression bonding part refers to a part where the thermoplastic continuous filaments of the nonwoven fabric are aggregated by thermocompression bonding between the convex part of the upper roll and the convex part of the lower roll. In this case, the portion that is press-contacted by the upper convex portion and the lower concave portion or the upper concave portion and the lower convex portion is not included in the thermocompression bonding here. Also, for example, when using a roll having a predetermined pattern of irregularities only on the upper side or the lower side, and other rolls using a flat roll without irregularities, the thermocompression bonding part is a convex part of the roll having irregularities. It refers to the portion where non-woven thermoplastic continuous filaments are aggregated by thermocompression bonding with a flat roll.

  The shape of the thermocompression bonding part in the non-woven fabric for filter of the present invention is not particularly defined, and consists of a pair of upper roll and lower roll in which a plurality of parallel grooves arranged on the surface are formed, In the embossing roll provided so that the groove of the upper roll and the groove of the lower roll intersect at a certain angle, when the upper roll convex part and the lower roll convex part are thermocompression bonded, Alternatively, even when a roll having a predetermined pattern of irregularities is used only on the lower side and a flat roll having no irregularities is used for the other rolls, the shape of the thermocompression bonding part is circular, triangular, quadrangular, parallelogram, elliptical. A shape, a rhombus, etc. may be sufficient. The arrangement of these thermocompression bonding portions is not particularly defined, and may be arranged at equal intervals, randomly arranged, or a mixture of different shapes. Among these, from the viewpoint of the uniformity of the nonwoven fabric, those in which the thermocompression bonding portions are arranged at equal intervals are preferable. Furthermore, it consists of a pair of upper rolls and lower rolls in which a plurality of linear grooves arranged in parallel are formed on the surface in terms of partial thermocompression bonding without peeling the nonwoven fabric, and the grooves of the upper rolls And an embossing roll provided so as to intersect with the groove of the lower roll at a certain angle, a parallelogram shape formed by thermocompression bonding between the convex part of the upper roll and the convex part of the lower roll. preferable.

The nonwoven fabric for filters in the present invention preferably has a bending resistance of 2 to 80 mN. If the bending resistance is 2 mN or more, the strength and form retention of the nonwoven fabric tend to be good, which is preferable. In particular, the pleat workability tends to be good, which is preferable. In consideration of the basis weight and integration method of the nonwoven fabric, it is difficult for the filter nonwoven fabric of the present invention to have a value exceeding 80 mN. A more preferable bending resistance is 2 to 35 mN, a further preferable bending resistance is 2 to 25 mN, and further preferably 5 to 25 mN. Here, the measurement of the bending resistance in the present invention is performed on the Gurley testing machine described in 6.10.3 (a) of JIS-L1085 (1998 edition) (for example, Gurley / flexibility testing machine manufactured by Toyo Seiki Seisakusho Co., Ltd.). Is to be implemented. The bending resistance in the Gurley tester is obtained by the following method. That is, a test piece having a length L38.1 mm (effective sample length 25.4 mm) and a width d25.4 mm is taken from any 20 points of the sample. Here, in the long-fiber nonwoven fabric, the longitudinal direction of the nonwoven fabric is the length direction of the sample. This is because pleating is performed in the longitudinal direction of the nonwoven fabric. Each of the collected test pieces is attached to the chuck, and the chuck is fixed in accordance with the scale 1−1 / 2 ″ (1.5 inch = 38.1 mm) on the movable arm A. In this case, the sample length is 1/2 ″. (0.5 inch = 12.7 mm) is 1/4 "(0.25 inch = 6.35 mm) on the chuck, and 1/4" (0.25 inch = 6. 5) on the tip of the pendulum at the free end of the sample. 35 mm), the effective sample length required for measurement is the specimen length L minus 1/2 "(0.5 inch = 12.7 mm). Appropriate weights W _a , W _b , and W _c (g) are attached to a, b, and c (mm), the movable arm A is rotated at a constant speed, and a scale RG (mgf) when the test piece is separated from the pendulum B is obtained. Read the scale with the first decimal place. Although the weight attached to the weight attachment hole can be selected as appropriate, it is preferable to set the scale RG to be 4 to 6. The measurement is performed 5 times for each of the 20 test pieces, 200 times in total. The value of the scale RG is obtained by rounding off the second decimal place by using the following formula: The sample's bending resistance (mN) is the average value of 200 measurements. The following is calculated by rounding off the first place.

The basis weight of the non-woven fabric for filter of the present invention is preferably in the range of 90 to 350 g / m ² . When the basis weight is less than 90 g / m ² , the rigidity tends to be low and the collection performance tends to decrease, which is an undesirable direction. When the basis weight exceeds 350 g / m ² , the basis weight is too high and the pressure loss tends to increase, which is also not preferable from the viewpoint of cost. A more preferable range of the basis weight is 100 to 320 g / m ² . The basis weight here means that three samples of 50 cm in length and 50 cm in width are taken and each weight is measured, the average value of the obtained values is converted per unit area, and the first decimal place is rounded off. Is required.

  The filter nonwoven fabric of the present invention is preferably a long fiber nonwoven fabric produced by a spunbond method. The long fiber nonwoven fabric produced by the spunbond method is particularly preferable when used in a pleated shape because it is excellent in rigidity in the longitudinal direction of the nonwoven fabric. Here, the spunbond method is a method in which a melted raw material polymer is extruded from a nozzle and is drawn and drawn at a speed of 2500 to 5000 m / min with a high-speed suction gas to form a filament. It is the method of making it the sheet | seat integrated by making it gather and making a fiber web and carrying out the thermocompression bonding of this fiber web continuously.

The filter nonwoven fabric of the present invention preferably has a dust collection performance of 30 to 90%, more preferably 35 to 90%. Here, the dust collection performance is measured by the following measuring method or a measuring method that can obtain the same result. That is, three samples of 15 cm × 15 cm are collected from an arbitrary portion of the nonwoven fabric, and the collection performance of each sample is measured with the collection performance measuring apparatus 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 the measurement of the collection efficiency, a solution containing polystyrene particles (for example, Nacalai Tech 0.309 U polystyrene 10 wt% solution) is diluted with distilled water (for example, Nacalai Tech 0.309 U is diluted up to 200 times). Fill 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 ³ (0.01 ft ³ )), the dust number D2 upstream of the sample M and the dust number D1 downstream are set to a particle size of 0 with a particle counter 6 (for example, KC-01D manufactured by Rion). Each value is measured in the range of 3 to 0.5 μm, and the value obtained by rounding off the first decimal place of the numerical value obtained by the following formula is the collection performance (%).
Collection performance (%) = [1- (D1 / D2)] × 100
Here, D1: downstream dust count (total of 3 times)
D2: Number of upstream dust (total of 3 times).

The non-woven fabric for a filter of the present invention preferably has a running time of 1000 to 5000 hours, more preferably 1500 to 4000 hours in a dust wiping-off test. Here, the dust wiping-out test is measured by the following measuring method or a measuring method that can obtain the same result. That is, three samples of 15 cm × 15 cm are collected from an arbitrary portion of the nonwoven fabric, and each sample is measured with the dust wiping-off test apparatus shown in FIG. This test apparatus has a configuration in which a dust supply device 8 is connected to an upstream side of a sample holder 1 for setting a test sample M, and a flow meter 3, a flow rate adjusting valve 4, a blower 5, and a pulse jet device 9 are connected to a downstream side. It has become. The evaluation area of the test sample is 0.01 m ² . A pressure gauge 10 is connected to the sample holder 1 so that the pressure loss of the sample M can be measured. In the dust removal test, JIS15 standard powder is supplied from the dust supply device 8 to a concentration of 20 g / m ³ and the flow rate adjusting valve is set so that the filter passing speed is 1.5 m / min. 4. Adjust the air volume at 4 and continuously supply dust at a constant concentration. When the pressure loss of the sample reaches 1500 Pa, 0.1 MPa of compressed air of 0.5 MPa is injected from the pulse jet device 9 to the sample. The attached dust is wiped off. Measure the operating time (hr) until the number of dust removals reaches 200 times, obtain the average value of the three test results, and use the value rounded to the first place as the operating time (hr) It is.

  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 non-woven fabric for filters of the present invention is widely used as a filter application, but is preferably used as an industrial filter because of its excellent mechanical strength and rigidity and excellent dust removal performance. Particularly preferably, the pleated cylindrical unit is used for cleaning a bag filter such as a dust collector or a liquid filter such as an electric discharge machine, and further used for cleaning intake air of a gas turbine or an automobile engine. It is used for an intake filter. In particular, in a bag filter for a dust collector, the non-woven fabric of the present invention having excellent strength is preferable because it removes dust accumulated on the filter surface layer during use, and is subjected to a removal process with 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 in the following Example is measured by 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 rising rate of 20 ° C./min, and the temperature giving an extreme value in the obtained melting endotherm curve was defined as the melting point. Further, for a resin whose melting endotherm curve does not show an extreme value in a differential scanning calorimeter, the resin was heated on a hot plate and the temperature at which the resin was melted by microscopic observation was taken as the melting point.

(2) Intrinsic viscosity IV
The intrinsic viscosity of the polyester was measured by the following method.
8 g of a sample was dissolved in 100 ml of orthochlorophenol, and a relative viscosity η _r was determined by the following formula using an Ostwald viscometer at a temperature of 25 ° C.
η _r = η / η ₀ = (t × d) / (t ₀ × d ₀ )
Where η: viscosity of the polymer solution
η ₀ : viscosity of orthochlorophenol
t: Dropping time of solution (second)
d: density of the solution (g / cm ³ )
t ₀ : Fall time of orthochlorophenol (seconds)
d ₀ : Orthochlorophenol density (g / cm ³ )
Then, from the relative viscosity η _r , the following formula:
IV = 0.0242η _r +0.2634
Was used to calculate the intrinsic viscosity IV.

(3) Fineness (decitex)
Ten small sample samples were taken at random from the non-woven fabric, photographed at 500 to 3000 times with a scanning electron microscope, 10 fibers from each sample were measured, and the diameter of 100 fibers in total was measured. The fiber diameter calculated by rounding off the first decimal place was corrected by the polymer density, and the first decimal place was rounded off.

(4) Weight per unit (g / m ² )
Three samples each having a length of 50 cm and a width of 50 cm were taken, the weight of each sample was measured, the average value of the obtained values was converted per unit area, and the first decimal place was rounded off.

(5) Tensile strength (N / 5cm)
A sample with a sample size of 5 cm × 30 cm is subjected to a tensile test with a constant-speed extension type tensile tester for three samples in the longitudinal and lateral directions under the conditions of a gripping interval of 20 cm and a tensile speed of 10 cm / min, and the sample breaks. The maximum strength when pulled to the maximum 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) 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 ³ (0.01 ft ³ )), the dust number D2 upstream of the sample M and the dust number D1 downstream are sampled by a particle counter 6 (manufactured by Lion Co., Ltd., KC-01D) with a dust particle size of 0.1. 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).

(7) Bending softness (mN)
The measurement of the bending resistance was carried out with a Gurley tester (Gare / flexibility tester manufactured by Toyo Seiki Seisakusyo Co., Ltd.) described in 6.10.3 (a) of JIS-L1085 (1998 edition). The bending resistance with a Gurley tester was determined by the following method. That is, a test piece having a length L38.1 mm (effective sample length 25.4 mm) and a width d25.4 mm is taken from any 20 points of the sample. Here, in the long-fiber nonwoven fabric, the longitudinal direction of the nonwoven fabric is the length direction of the sample. Each of the collected test pieces is attached to the chuck, and the chuck is fixed in accordance with the scale 1−1 / 2 ″ (1.5 inch = 38.1 mm) on the movable arm A. In this case, the sample length is 1/2 ″. (0.5 inch = 12.7 mm) is 1/4 "(0.25 inch = 6.35 mm) on the chuck, and 1/4" (0.25 inch = 6. 5) on the tip of the pendulum at the free end of the sample. 35 mm), the effective sample length required for measurement is the specimen length L minus 1/2 "(0.5 inch = 12.7 mm). Appropriate weights W _a , W _b , and W _c (g) are attached to a, b, and c (mm), the movable arm A is rotated at a constant speed, and a scale RG (mgf) when the test piece is separated from the pendulum B is obtained. Read the scale with the first decimal place. The weight attached to the weight attachment hole was set so that the scale RG was 4 to 6. The measurement was performed 5 times for each of the 20 test pieces, 200 times in total, and the following formula was calculated from the value of the obtained scale RG. The value of the bending resistance is obtained by rounding off the second decimal place, and the bending resistance (mN) of the sample is calculated by rounding the average value of 200 measurements to the first decimal place. Is.

(8) Dust removal property The dust removal property was measured by the following method.

Three samples of 15 cm × 15 cm were taken from an arbitrary part of the nonwoven fabric, and each sample was measured with a dust wiping-off test apparatus shown in FIG. This test apparatus has a configuration in which a dust supply device 8 is connected to an upstream side of a sample holder 1 for setting a test sample M, and a flow meter 3, a flow rate adjusting valve 4, a blower 5, and a pulse jet device 9 are connected to a downstream side. It has become. The evaluation area of the test sample was 0.01 m ² . A pressure gauge 10 is connected to the sample holder 1 so that the pressure loss of the sample M can be measured. In the dust removal test, JIS15 standard powder is supplied from the dust supply device 8 to a concentration of 20 g / m ³ and the flow rate adjusting valve is set so that the filter passing speed is 1.5 m / min. 4. Adjust the air volume at 4 and continuously supply dust at a constant concentration. When the pressure loss of the sample reaches 1500 Pa, 0.1 MPa of compressed air of 0.5 MPa is injected from the pulse jet device 9 to the sample. The adhering dust was removed. The operation time (hr) until the number of dust removals reached 200 times was measured, the average value of the three test results was determined, and the operation time (hr) was calculated by rounding off the first place.

Example 1
A polyethylene terephthalate (PET) having an intrinsic viscosity of IV 0.65 and a melting point of 260 ° C. added with 0.5 wt% of ethylene bis stearamide (hereinafter referred to as EBA, “Alflow” (registered trademark) H-50T manufactured by NOF Corporation) , 0.5% by weight of EBA added to copolymer polyester (CO-PET) having an intrinsic viscosity of IV 0.66 and an isophthalic acid copolymerization ratio of 11 mol% and a melting point of 230 ° C. were melted at 295 ° C. and 280 ° C., respectively. Polyethylene terephthalate is used as the core component and copolymer polyester is used as the sheath component. After spinning from the pores at a base temperature of 300 ° C. and a weight ratio of core: sheath = 80: 20, spinning is performed by an ejector at a spinning speed of 4300 m / min. The yarn was charged and opened by the method described above, and collected as a fiber web on a moving net conveyor. The collected fiber web was thermocompression bonded with an embossing roll having a crimping area ratio of 10% under the conditions of a temperature of 180 ° C. and a linear pressure of 70 kg / cm to obtain a spunbonded nonwoven fabric having a fineness of 2 dtex and a basis weight of 260 g / m ² . .

Example 2
Polyethylene terephthalate (PET) having an intrinsic viscosity of IV 0.65 and a melting point of 260 ° C. and 1.0 wt% of EBA on a copolymer polyester (CO-PET) having an intrinsic viscosity of IV 0.66 and an isophthalic acid copolymerization ratio of 11 mol% and a melting point of 230 ° C. % Added, melted at 295 ° C. and 280 ° C., respectively, using polyethylene terephthalate as the core component and copolymer polyester as the sheath component, spinning from the pores at a base temperature of 295 ° C. and a weight ratio of core: sheath = 82: 18. After taking out, spinning was performed by an ejector at a spinning speed of 4400 m / min, and the yarn was charged and opened by a known method, and collected as a fiber web on a moving net conveyor. The collected fiber web was thermocompression bonded with an embossing roll having a crimping area ratio of 18% under conditions of a temperature of 200 ° C. and a linear pressure of 60 kg / cm to obtain a spunbonded nonwoven fabric having a fineness of 3 dtex and a basis weight of 260 g / m ² . .

Example 3
A spunbonded nonwoven fabric was obtained in the same manner as in Example 2 except that the basis weight was 200 g / m ² .

Example 4
Except that EBA of Example 2 was changed to N-stearyl stearamide (“Nikka Amide S” (registered trademark) manufactured by Nippon Kasei Co., Ltd.), fineness of 3 dtex and basis weight of 260 g were the same as in Example 2. A spunbond nonwoven fabric of / m ² was obtained.

  The properties of the obtained nonwoven fabric are as shown in Table 1, but the nonwoven fabrics of Examples 1, 2, 3, and 4 were all excellent in tensile strength, bending resistance, and collection performance. Moreover, it was excellent also in dust removal property, and the operating time of the dust removal property test was as good as 1920 hours, 1830 hours, 1780 hours, and 1850 hours, respectively.

Comparative Example 1
Polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 and a melting point of 260 ° C. is melted at 295 ° C., spun from the pores at a die temperature of 300 ° C., then spun at a spinning speed of 4400 m / min by an ejector, and a moving net conveyor Collected as a fiber web on top. The collected fiber web is thermocompression bonded with an embossing roll with a crimping area ratio of 16% under the conditions of a temperature of 240 ° C. and a linear pressure of 60 kg / cm to obtain a spunbonded nonwoven fabric having a fineness of 2 dtex and a basis weight of 260 g / m ^2. It was.

Comparative Example 2
Polyethylene terephthalate (PET) having an intrinsic viscosity of IV 0.65 and a melting point of 260 ° C., and a copolymer polyester (CO-PET) having an intrinsic viscosity of IV 0.66 and an isophthalic acid copolymerization ratio of 11 mol% and a melting point of 230 ° C. are 295 ° C. and After melting at 280 ° C., using polyethylene terephthalate as the core component and copolymer polyester as the sheath component, spinning from the pores at a base temperature of 300 ° C., and a weight ratio of core: sheath = 80: 20, spinning speed is 4000 m / m by the ejector. Spinned in minutes and collected as a fiber web on a moving net conveyor. The collected fiber web is thermocompression bonded with an embossing roll with a crimping area ratio of 16% under the conditions of a temperature of 200 ° C. and a linear pressure of 70 kg / cm to obtain a spunbond nonwoven fabric having a fineness of 3 dtex and a basis weight of 260 g / m ^2. It was.

Comparative Example 3
Polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 and a melting point of 260 ° C. is melted at 295 ° C., spun from the pores at a die temperature of 300 ° C., then spun at a spinning speed of 4400 m / min by an ejector, and a moving net conveyor Collected as a fiber web on top. The collected fiber web is thermocompression bonded with an embossing roll with a crimping area ratio of 3% under the conditions of a temperature of 180 ° C. and a linear pressure of 30 kg / cm to obtain a spunbond nonwoven fabric having a fineness of 3 dtex and a basis weight of 200 g / m ^2. It was.

  The properties of the obtained nonwoven fabric are as shown in Table 1, but the nonwoven fabrics of Comparative Examples 1 and 2 were all excellent in tensile strength, bending resistance, and collection performance. However, it was inferior to the dust wiping property, and the operating time of the dust wiping property test was less than 1000 hours. The nonwoven fabric of Comparative Example 3 was low in tensile strength and bending resistance, inferior in mechanical strength, and inferior in collection performance and dust wiping off property.

  The non-woven fabric for filter of the present invention is excellent in dust wiping-off property, and is also excellent in mechanical properties and rigidity, and can be suitably used particularly as an industrial air filter.

It is the schematic of a collection performance measuring device. It is the schematic of the dust wiping-off evaluation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample holder 2 Dust storage box 3 Flowmeter 4 Flow control valve 5 Blower 6 Particle counter 7 Switching cock 8 Dust supply device 9 Pulse jet device 10 Pressure gauge M Measurement sample

Claims (5)

  A nonwoven fabric for a filter comprising a polyester filament containing 0.1 to 5.0 wt% of an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide. A nonwoven fabric for a filter comprising a polyester-based sheath-core filament containing 0.1 to 5.0 wt% of an aliphatic bisamide and / or an alkyl-substituted aliphatic monoamide as a sheath component.   The filter nonwoven fabric according to claim 1 or 2, wherein the filter nonwoven fabric is integrated by partial thermocompression bonding, and the area ratio of the partial thermocompression bonding is 5 to 50%.   The nonwoven fabric for filters according to any one of claims 1 to 3, wherein the bending resistance of the nonwoven fabric for filters is 2 to 80 mN. It uses for a pleat filter, The nonwoven fabric for filters in any one of Claims 1-4 characterized by the above-mentioned.

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