JP5530249B2 - Filter media and cartridge filter for liquid filters - Google Patents

Description

  The present invention is a filter material for a liquid filter using a liquid as a medium, exhibits excellent heat resistance, has good collection properties, and can maintain a low pressure loss, and the filter The present invention relates to a cartridge filter containing a material. The present invention relates to a filter medium for a liquid filter and a cartridge filter used for removing suspended substances and impurities from high-temperature water of 100 ° C. or higher such as condensate in a thermal power plant and heater drain water.

  Fields of application of filter media that use high-temperature water as a medium include thermal power plant condensate filtration, nuclear power plant condensate filtration, general industrial condensate filtration, and heater drain water filtration. In these fields, a filter called a precoat filter, which satisfies the removal performance and life by coating iron oxide fine particles on the surface of a core filter having a filtering action, or a disposable filter is used (Patent Literature). 1 and 2).

  The pre-coated filter has a short life, and requires backwashing, pre-coating treatment, and replacement of the filter medium every two to three weeks.

  As for the disposable type, a pleated cartridge (Patent Document 3) made of a synthetic resin (polypropylene) and the like, including a thread-wound filter wound with a heat-resistant cotton thread, are proposed. However, the thread-wound filter has a feature that it is inexpensive, but it has not only poor trapping properties, but also has a problem that the gap needs to be made small in order to improve the trapping properties and the life is short. The filter described in Patent Document 3 has low heat resistance, so it is necessary to sufficiently reduce the temperature of the condensate, and it is difficult to use for a long time, and the thickness of the filter medium is large. The problem is that the filtration area cannot be expanded and, as a result, the pressure loss is large when the fluid flows, and the life cannot be extended sufficiently.

There is also a proposal for a pleated filter material using a long-fiber nonwoven fabric using polyphenylene sulfide having heat resistance (Patent Documents 4 and 5). Patent Document 5 discloses a polyphenylene sulfide non-woven fabric having a specific rigidity and a fragile air permeability in the range of 3 to 40 cc / cm ² , a non-woven fabric obtained by laminating a plurality of these, and a pleat process A cartridge filter is mentioned.

JP-A-8-71316 JP-A-9-187605 JP 2000-197803 A JP 2008-223209 A JP-A-2005-154920

  However, the poniphenylene sulfide non-woven fabric described in Patent Document 4 has a large single yarn denier (fiber diameter), and cannot collect a substance having a small particle diameter, and cannot be used for applications such as a fine particle removal filter. In particular, in a condensate filter, it is necessary to remove about 90% of iron fine particles having a size of 1 to 3 μm, and it is difficult to use for this purpose. In addition, the nonwoven filter medium described in Patent Document 5 also has a high Frazier permeability and does not provide sufficient trapping properties as a liquid filter.

  As described above, under the present circumstances, a filter medium having a long life while having heat resistance and high collection property, and a pleated cartridge using the same have not been proposed.

  Therefore, an object of the present invention is to provide a filter medium that uses a non-woven fabric having heat resistance and can have a long life while having high collection ability.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors use a heat-resistant polyphenylene sulfide (hereinafter abbreviated as PPS) long-fiber nonwoven fabric, and a fiber that satisfies the trapping property and the pleat property alone. After setting the diameter, porosity, and basis weight, the filter media thickness is reduced compared to the conventional one, increasing the number of pleats, thereby increasing the effective filtration area in the cartridge, resulting in a long life The inventors have found that a filter medium and a cartridge filter can be obtained, and have completed the present invention. Specifically, the present invention has the following aspects.

[1] A filter material for a liquid filter including a filter layer,
The filtration layer is a spunbond nonwoven fabric composed of polyphenylene sulfide long fibers,
The average fiber diameter of the polyphenylene sulfide long fibers is 1 to 10 μm,
The filter material for liquid filters in which this filtration layer has a basis weight of 50 to 300 g / m ² and a porosity of 40 to 70%.
[2] The filter material for a liquid filter according to [1], wherein the polyphenylene sulfide long fibers have a crystallinity of 18% or more.
[3] A cartridge filter comprising the filter material for liquid filter according to the above [1] or [2], wherein the filter material for liquid filter has a pleated shape.
[4] A method for using a cartridge filter, wherein a medium that is heated water having a temperature of 100 ° C. or higher is filtered by the cartridge filter according to [3].

  The filter medium for a liquid filter of the present invention is thinner than the conventionally proposed filter medium, has excellent collection performance, has rigidity for maintaining a pleated form, and is excellent in heat resistance. Therefore, according to the pleated cartridge formed using the filter material for a liquid filter of the present invention, the effective filtration area can be increased, the pressure loss when flowing the liquid can be reduced, and the life can be extended.

  Hereinafter, the present invention will be described in detail.

<Filtration material for liquid filter>
One aspect of the present invention is a filter material for a liquid filter including a filtration layer, wherein the filtration layer is a spunbond nonwoven fabric composed of polyphenylene sulfide long fibers, and the average fiber diameter of the polyphenylene sulfide long fibers is from 1 to Provided is a filter medium for a liquid filter, which is 10 μm, and the filtration layer has a basis weight of 50 to 300 g / m ² and a porosity of 40 to 70%.

  In the present invention, polyphenylene sulfide (hereinafter also referred to as PPS) long fibers are used to form a spunbonded nonwoven fabric as a filtration layer. PPS is advantageous in that it has excellent heat resistance. The PPS preferably has a para-phenylene sulfide repeating unit from the viewpoint of yarn production, and is preferably a linear PPS.

  In particular, the proportion of para-phenylene sulfide repeating units in all repeating units of PPS is preferably 85% or more, and more preferably 90% or more.

  PPS is substantially composed only of phenylene sulfide repeating units, but a small amount of other repeating units such as aromatic sulfide copolymers and mixtures (for example, 15% by mass or less) within a range not impairing the effects of the present invention. May be included. Moreover, the PPS long fiber may contain arbitrary additive components, such as a coloring agent, a titanium oxide, a ultraviolet absorber, a heat stabilizer, and an oxidation spinning agent.

  The melt flow rate of PPS is, for example, preferably 10 to 700 g / 10 min, and more preferably 50 to 500 g / 10 min. When the melt flow rate is 700 g / 10 min or less, it is advantageous in that the heat resistance of the filter material for a liquid filter is better, and when it is 10 g / 10 min or more, processability such as yarn forming property is better. It is advantageous in some respects. The melt flow rate described in the present specification is a value measured under conditions of a load of 5 kg and a temperature of 315.6 ° C. according to the ASTM-D1238-82 method.

  In this invention, the nonwoven fabric which consists of a PPS long fiber manufactured by the spun bond method is used for the filter material for filters. The PPS long fiber nonwoven fabric by the spunbond method has high uniformity in fiber diameter, and is excellent in terms of strength and hardness. As a specific production method, it can be produced by a known method such as the method described in International Publication No. WO2008 / 035775 (in particular, paragraphs [0043] to [0053]).

  The average fiber diameter of the PPS long fibers in the spunbonded nonwoven fabric used in the present invention is 1 to 10 μm, preferably 2 to 6 μm. When the average fiber diameter is smaller than 1 μm, it is not preferable from the viewpoint of manufacturing problems such as yarn breakage and the strength of the nonwoven fabric. In addition to insufficient trapping performance, it is easy to clog because of the small pores, and only a filter material with a short life can be obtained. The average fiber diameter described in the present specification is an average value (for example, a number average value of 50 points) of fiber diameters (maximum diameter when the cross section is other than a circle) measured using a microscope.

The crystallinity of the PPS long fiber is preferably 18% or more, and more preferably 25 to 50%. When the crystallinity is less than 18%, the PPS fiber is likely to be thermally contracted, and not only is it shrunk at the time of pleating, but also tends to be leaked when high-temperature water is passed through the filter. When the crystallinity exceeds 50%, the thermal adhesive force between the fibers tends to decrease, and the strength tends to decrease and peeling tends to occur. The degree of crystallinity described in the present specification is a value calculated according to the following formula from the calorific value measured using a differential scanning calorimeter (DSC). In the formula, the heat of fusion of the complete crystal is the theoretical heat of fusion of 146.2 J / g of the complete crystal of polyphenylene sulfide.
Crystallinity [%] = 100 × [(heat quantity of melting part) − (heat quantity of cold crystal part)] / (heat of fusion of complete crystal)
(In the formula, the units of the heat amount are all [J / g].)

  The spunbonded nonwoven fabric used in the present invention is substantially composed of PPS long fibers, but, for example, polyethylene, polypropylene, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide, as long as the effects of the present invention are not impaired. In addition, a small amount (for example, 15% by mass or less) of other fibers such as polyetheretherketone, polyetherimide, and aromatic sulfide may be included. The spunbond nonwoven fabric may contain any additive component such as a colorant, titanium oxide, an ultraviolet absorber, a heat stabilizer, an oxidation spinning agent, and a curing agent.

  The spunbonded nonwoven fabric forming the filtration layer may be a single nonwoven fabric or a laminate of a plurality of nonwoven fabrics. Such a single-layer or multiple-layer spunbonded nonwoven fabric can be subjected to hot embossing or thermal calendering as required, and thereby the basis weight and porosity are required as filter media for filters. Can be adjusted. As processing conditions in hot embossing or thermal calendaring, the temperature is preferably 160 ° C. to 260 ° C., and the pressure is preferably at least 50 N / cm or more.

Basis weight of the filter layer is 50 to 300 g / ^{m 2,} preferably 100 to 200 g / ^{m 2.} When the weight per unit area is less than 50 g / m ² , not only the trapping property is insufficient, but also the retention property at the time of pleating may be problematic. On the other hand, if the basis weight exceeds 300 g / m ² , the pressure loss when the liquid flows is increased, which affects the pumping ability to send the liquid, which is not only a problem in terms of energy used, but also the thickness of the filtration layer. Therefore, the number of pleats entering the cartridge is reduced, the filtration area is reduced, and the life is shortened. The basis weight described in the present specification is a value measured according to JIS L 1906 5.2 “Mass per unit area”.

The porosity of the filtration layer is 40 to 70%, preferably 50 to 60%. When the porosity is less than 40%, the pressure loss increases and the amount of the substance trapped inside the filtration layer is also reduced, so that the life is shortened. On the other hand, if the porosity exceeds 70%, the particles collected inside the filtration layer are liable to flow out again, and the collection property is lowered, which is not preferable. In particular, when the filter material for a liquid filter of the present invention is used for condensate applications, the medium flow rate is large, and the above-mentioned collected particles are liable to re-flow, so the porosity is 60% or less. It is preferable to make it. The porosity described in the present specification is a value calculated according to the following formula from the above-mentioned basis weight value and the filtration layer thickness value. The thickness is measured using, for example, a pressurizer with a load of 2 kPa (20 kf / cm ² ). In the formula, the specific gravity of 1.35 g / cm ³ of polyphenylene sulfide is used as the specific gravity.
Porosity (%) = {1−weight per unit area (g / m ² ) / specific gravity (g / cm ³ ) / thickness (mm) / 1000)} × 100

Furthermore, the balance of the basis weight and porosity of the above it is preferable to a Frazier air permeability in 0.3~1cc / cm ² / sec, more be a 0.5~0.9cc / cm ² / sec preferable. When the fragile air permeability is less than 0.3 cc / cm ² / sec, the flow pressure pressure loss tends to be high and the life tends to be shortened. When it exceeds 1 cc / cm ² / sec, the trapping property tends to be insufficient. The fragile air permeability described in the present specification is a value measured according to JIS L 1096 8.27.1 “Breathability” Method A Frazier Form Method.

  The filter material for a liquid filter of the present invention may be composed of only the filtration layer described above. For example, the support material for improving the pleat workability or maintaining the pleat shape, and the life of the liquid may be improved. You may further have a pre filter layer etc. for adsorb | sucking a specific substance.

<Cartridge filter>
Another aspect of the present invention provides a cartridge filter comprising the above-described filter material for a liquid filter of the present invention, and wherein the filter material for a liquid filter has a pleated shape. The filter medium for a liquid filter of the present invention can be suitably used particularly as a cartridge filter by increasing the filtration surface by pleating. Although the method of the said pleating process is not specifically limited, For example, the processing method using a knife type processing machine, a rotary type processing machine, etc. is mentioned.

  The cartridge filter may be composed only of the filter material for the liquid filter, but typically, the cartridge filter is formed by combining components such as the sub filtration layer, the inner cylinder, the outer cylinder, and the end plate with the filter medium for the liquid filter. Form.

  As a subfiltration layer, the prefilter layer for improving the collection property and lifetime of the filter material for liquid filters, the mesh layer or the nonwoven fabric layer for improving pleat moldability and pleat retention property, etc. can be provided. These subfiltration layers can be provided by a method of overlapping with a filter material for liquid filter at the time of pleating, a method of pasting the filter material for liquid filter of the present invention and a known means such as an embossed composite in advance.

  However, since it is necessary to select a material having a high temperature suitability as a material for the subfiltration layer, for example, a nonwoven fabric and a mesh film made of PPS resin are preferable.

  Further, materials such as an inner cylinder, an outer cylinder, and an end plate are also preferably made of materials that are suitable for high temperatures, and preferable materials for these members include PPS resin and PVDF (polyvinylidene fluoride) resin.

  For example, the cartridge filter of the present invention can be manufactured using the above-described constituent members. As a typical configuration of the cartridge filter, an inner cylinder, a pleated sheet wound around the inner cylinder (for example, a laminated body of a filter material for a liquid filter and a sub filtration layer made of a filtration layer), The structure which consists of an outer cylinder (or elastic sheet material, a net-like base material etc.) which covers this pleated sheet | seat, and an end plate is mentioned.

  The cartridge filter can be manufactured, for example, by the following method. First, a pleated sheet is wound around the inner cylinder by overlapping a filtration layer made of a spunbond nonwoven fabric on the inner cylinder and, if necessary, a secondary filtration layer, and the pleated sheets are wound around the inner cylinder with an adhesive or Fix and seal by thermal bonding. Next, the sheet is fixed by providing a plastic tube (outer tube), an elastic sheet material, a net-like base material, or the like so as to cover the pleated sheet. The end face of the cylindrical product thus obtained is treated by sealing by heat treatment using a resin end plate, sealing by adhesion of a metal or resin plate by an epoxy resin or the like. About the shape of an end plate, the thing of a well-known shape can be suitably selected according to the container (housing) of a cartridge filter. A cartridge filter can be manufactured as described above.

<How to use the cartridge filter>
Another aspect of the present invention provides a method for using a cartridge filter in which a medium that is heated water having a temperature of 100 ° C. or higher is filtered by the cartridge filter of the present invention described above. The cartridge filter of the present invention is excellent in heat resistance while having high collection property and long life, and therefore can be preferably applied to remove suspended substances, impurities, etc. from heated water at a temperature of 100 ° C. or higher. Examples of the heated water at 100 ° C. or higher include condensate from a thermal power plant and heater drain water, and condensate generated in boilers used in various industries.

  The present invention will be described more specifically based on the following examples and comparative examples, but the present invention is not limited to these examples. In addition, the physical-property value of the filter material for liquid filters and the characteristic value evaluated in the Example and the comparative example were measured with the following method.

(1) Average fiber diameter Take 10 images of a sample at a microscope magnification of 2500 times (measure 5 points per site), measure the fiber diameter of 50 points, and average the number (number) (Average) was defined as the average fiber diameter. Subsequently, the average fineness [dtex] was calculated from the average fiber diameter.

(2) Weight per unit area Measured according to JIS L 1906 5.2 “Mass per unit area”.

(3) Porosity It calculated | required from the thickness [mm] measured using the pressurizer of the fabric weight measured by said (2), and a load of 2 kPa (20 gf / cm < ² >). It calculated according to the following formula from the specific gravity of the material used with each filter medium.
Porosity (%) = {1−weight per unit area (g / m ² ) / specific gravity (g / cm ³ ) / thickness (mm) / 1000)} × 100
In the formula, the specific gravity of 1.35 g / cm ³ of polyphenylene sulfide was used as the specific gravity.

(4) Fragile Breathability JIS L 1096 8.27.1 “Breathability” Method A Measured according to the Frazier method.

(5) Crystallinity Using a differential scanning calorimeter (TA Instruments, Inc .: DSC2920), a 5.0 mg sample was measured under the following conditions, and the crystallinity [%] was calculated according to the following formula (2). Calculated. In the formula, the theoretical heat of fusion of 146.2 J / g of the complete crystal of polyphenylene sulfide was used as the heat of fusion of the complete crystal.
Measurement atmosphere: nitrogen gas 150 mL / min, temperature rising rate: 20 ° C./min
Measurement range: 30-350 ° C
Crystallinity [%] = 100 × [(heat quantity of melting part) − (heat quantity of cold crystal part)] / (heat of fusion of complete crystal)
In addition, the unit of the said calorie | heat amount is all [J / g].

(6) Collectability (%)
A test solution having a concentration of 10 ppm obtained by dispersing JIS11 seed dust in water was passed through the cartridge filters in Examples and Comparative Examples so as to flow from the outside to the inside at a flow rate of 10 L / min while stirring uniformly. A pre-filtration solution and a post-filtration solution 30 minutes after the start of water flow were collected, diluted 100-fold with ultrapure water, and a particle size distribution analyzer (LS-200 (Shilling sampler) manufactured by PARTICLE MEASURING SYSTEMS INC.) And Liqulaz- S02-HF (particle sensor)) was used, and the trapping ability of 1.0 μm (measuring range 0.97 to 1.03 μm) diameter particles was determined according to the following formula.
Collectability (%) = {(A−B) / A} × 100
A: Number of particles before filtration B: Number of particles after filtration

(7) Filter life (min)
A test solution having a concentration of 300 ppm obtained by dispersing JIS11 seed dust in water was allowed to flow through the cartridge filters in Examples and Comparative Examples at a flow rate of 10 L / min from the outside to the inside while stirring uniformly. The time required for the pressure loss to rise by 0.2 MPa from the pressure loss was defined as the filter life.

(8) Flow pressure loss (KPa)
The initial pressure loss was measured when the same test solution as in (7) above was passed through the cartridge filters in the examples and comparative examples so as to flow from the outside of the filter to the inside at a flow rate of 10 L / min. did.

(9) Melt flow rate It was measured under the conditions of a load of 5 kg and a temperature of 315.6 ° C. according to ASTM-D1238-82 method. The unit is [g / 10 min].

(10) Heat resistance The filter media of Examples and Comparative Examples are placed in a stainless steel sealed pot together with water so that the filter media can be completely immersed in water, and left in a dryer at 175 ° C. for about half a year. After hydrothermal treatment and taking out over time, and after natural drying, changes in warp and shrinkage in the warp and weft directions of the filter medium and changes in the strength in the warp direction were examined.

Shrinkage after hot water treatment Shrinkage (%) = (L0−L1) / L0 × 100%
(L0: initial mark length, L1: mark length after hydrothermal treatment)

Tensile strength retention after hydrothermal treatment, and elongation retention after hydrothermal treatment Using A & D Tensilon type tensile tester, the breaking strength and elongation are as follows: grip width 20 mm, chuck length 100 mm, pulling speed 200 mm / min. Was measured.

  From the strength and elongation after the hot water treatment for a predetermined time, the retention rate was calculated by the following formula.

Strength retention (%) = (P1 / P0) × 100
(P0: warp strength before hot water treatment, P1: warp strength after hot water treatment)
Elongation retention (%) = (X1 / X0) × 100
(X0: elongation at break before hydrothermal treatment, X1: elongation at break after hydrothermal treatment)

[Production Example 1]
A linear (ie, para) polyphenylene sulfide (PPS) polymer having a melt flow rate of 70 g / 10 min is melted and extruded from a spinneret having a nozzle diameter of 0.25 mm at a discharge rate of 0.5 g / min per single hole. , Spunbonded nonwoven fabric with a crystallinity of 31% and an average fiber diameter of 7 μm, drawn at a spinning speed of 8 × 10 ³ m / min while being sucked by an ejector, collected and deposited on a moving porous belt a) was obtained.

[Production Example 2]
A linear PPS polymer having a melt flow rate of 70 g / 10 min is melted, extruded from a spinneret having a nozzle diameter of 0.25 mm at a discharge rate of 0.3 g / min per single hole, and sucked with an ejector, and a spinning speed of 7 × The spunbonded nonwoven fabric (b) having a crystallinity of 30% and an average fiber diameter of 5 μm was obtained by stretching at 10 ³ m / min and collecting and depositing on the moving porous band.

[Production Example 3]
A linear PPS polymer having a melt flow rate of 70 g / 10 min is melted, extruded from a spinneret with a nozzle diameter of 0.25 mm at a discharge rate of 1.4 g / min per single hole, and sucked with an ejector, and a spinning speed of 8 × The spunbonded nonwoven fabric (c) having a crystallinity of 21% and an average fiber diameter of 12 μm was obtained by stretching at 10 ³ m / min and collecting and depositing on the moving porous band.

[Production Example 4]
A linear PPS polymer having a melt flow rate of 70 g / 10 min is melted, extruded from a spinneret having a nozzle diameter of 0.25 mm at a discharge rate of 0.5 g / min per single hole, and sucked with an ejector, and a spinning speed of 5 × The spunbonded nonwoven fabric (d) having a crystallinity of 15% and an average fiber diameter of 12 μm was obtained by stretching at 10 ³ m / min and collecting and depositing on the moving porous band.

[Example 1]
For forming a filtration layer, four spunbond nonwoven fabrics (a) were laminated so that the basis weight was 200 g / m ^2, and then a rectangular pattern embossing (crimp area ratio 11.4%) roll heated to 260 ° C. A filtration layer (1) was obtained by partially thermocompression bonding with a flat roll at a linear pressure of 50 N / mm. The physical properties of this filtration layer (1) are shown in Table 1, and the heat resistance is shown in Table 2. Next, the filtration layer (1) was processed to a height of 1 cm with a pleating machine (manufactured by Toyo Koki Co., Ltd.) to obtain a pleated substrate.

The pleated base material is cut so that there are 100 ridges, and the end faces parallel to the ridges are fused together using an ultrasonic plastic welder (W3080-20 model, manufactured by Nippon Future Co., Ltd.). Got. This pleated tube is covered with an inner tube (PPS inner diameter 33 mm, thickness 3 mm), and the outer surface (PPS inner diameter 66 mm, thickness 3 mm) and a PPS resin plate are used to seal the end face by a heat-sealing machine, and a cartridge filter (Height 250 mm, filter area 0.36 m ² ) was produced. Table 1 shows the results of trapping performance and flow rate pressure loss of this cartridge filter.

[Example 2]
With spunbonded nonwoven fabric (b), except for changing the basis weight to 100 g / m ² in the same manner as in Example 1 to obtain filtration layer (2). The physical properties of this filtration layer (2) are shown in Table 1, and the heat resistance is shown in Table 2.

Next, a cartridge filter (height 250 mm, filter area 0.36 m ² ) was produced in the same manner as in Example 1 by using the filtration layer (2). Table 1 shows the results of trapping performance and flow rate pressure loss of this cartridge filter.

[Comparative Example 1]
A rectangular pattern embossed (crimp area ratio 11.4%) roll and a flat roll which were prepared so that the spunbond nonwoven fabric (c) obtained in Production Example 3 was adjusted to have a basis weight of 200 g / m ² and heated to 260 ° C. In between, the inside of the spunbonded nonwoven fabric (c) was partially thermocompression bonded at a linear pressure of 50 N / mm to obtain a filtration layer (3). The physical properties of the filtration layer (3) are shown in Table 1, and the heat resistance is shown in Table 2.

Next, a cartridge filter (height 250 mm, filter area 0.30 m ² ) was produced in the same manner as in Example 1 by using the filtration layer (3). However, since the thickness of the filtration layer was large, the number of peaks was 80. Table 1 shows the results of trapping performance and flow rate pressure loss of this cartridge filter.

[Comparative Example 2]
A rectangular pattern embossed (crimp area ratio 11.4%) roll and a flat roll, which were prepared so that the spunbond nonwoven fabric (c) obtained in Production Example 3 had a basis weight of 350 g / m ² and was heated to 260 ° C. In between, the inside of the spunbonded nonwoven fabric (c) was partially thermocompression bonded at a linear pressure of 200 N / mm to obtain a filtration layer (4). The physical properties of this filtration layer (4) are shown in Table 1, and the heat resistance is shown in Table 2.

Next, a cartridge filter (height 250 mm, filter area 0.36 m ² ) was produced in the same manner as in Example 1 by using the filtration layer (4). Table 1 shows the results of trapping performance and flow rate pressure loss of this cartridge filter.

[Comparative Example 3]
A rectangular pattern embossed (crimped area ratio 11.4%) roll and a flat roll prepared by adjusting the spunbond nonwoven fabric (d) obtained in Production Example 4 to have a basis weight of 100 g / m ² and heated to 260 ° C. In between, the inside of the spunbond nonwoven fabric (d) was partially thermocompression bonded at a linear pressure of 50 N / mm to obtain a filtration layer (5). The physical properties of the filtration layer (5) are shown in Table 1, and the heat resistance is shown in Table 2.

  Next, we tried to make a pleating process and a cartridge filter using the filtration layer (5), but the nonwoven fabric contracted during the pleating process and when the end plate was thermally bonded, resulting in a seal failure, producing a cartridge filter. The result was not possible.

  About Example 1 and 2, it turns out that the collection property of a particle | grain with a particle size of 1 micrometer is about 90%, and is a filter excellent in the balance of flow volume pressure loss and lifetime.

  On the other hand, since Comparative Example 1 has a large average fiber diameter and a high porosity, it has a poor trapping property. In Comparative Example 2, although the weight per unit area is increased and the porosity is lowered, the trapping property is slightly increased. However, since the pores are small, the flow pressure pressure loss is high, and the filter has a short life. The filter medium of Comparative Example 3 undergoes thermal shrinkage and is inferior in heat resistance.

  INDUSTRIAL APPLICABILITY The present invention is useful for a filter medium and a cartridge filter used for removing suspended substances and impurities from high-temperature water such as condensate in a thermal power plant and heater drain water.

Claims (3)

A cartridge filter including a filter material for a liquid filter including a filter layer ,
The filtration layer is a spunbond nonwoven fabric composed of polyphenylene sulfide long fibers,
The average fiber diameter of the polyphenylene sulfide long fibers is 1 to 10 μm,
The filtration layer may possess a basis weight 50 to 300 g / m ^2, and a porosity of 40% to 70%,
A cartridge filter, wherein the filter material for a liquid filter has a pleated shape . The cartridge filter according to claim 1, wherein the polyphenylene sulfide long fiber has a crystallinity of 18% or more. A method for using a cartridge filter, wherein a medium that is heated water having a temperature of 100 ° C or higher is filtered by the cartridge filter according to claim 1 or 2 .