JPH0691105A - Cartridge filter - Google Patents

Abstract

(57) [Summary] [Purpose] A cylindrical cartridge filter removes residual chlorine in the filtrate while maintaining high filtration accuracy. [Structure] At least 50% by weight of ultrafine fibers having a thickness of 0.5 denier or less is contained on the porous core tube (2) or the fiber molding core tube (4), and at least 30% by weight of the ultrafine fibers is contained. A polyamide ultrafine fiber nonwoven fabric was wound to form a filtration layer (3) having a fiber density of 0.18 to 0.35 g / m ² .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is a cartridge type filter which can adsorb at least residual chlorine in a filtrate and which contains a polyamide ultrafine fiber having a large fiber surface area in a filter layer. The present invention relates to a cartridge filter capable of improving the flavor of drinking water.

[0002]

2. Description of the Related Art A cartridge type filter using a fiber as a constituent of a filter layer usually has a filter layer made of fibers formed in a hollow cylindrical shape, and an object to be filtered is a central portion of the hollow cylinder. There is a method in which the object to be filtered is introduced from the hollow part by passing through the filter layer by being collected and filtered in the opposite direction, or flows out to the outside of the hollow cylindrical filter layer. It is useful for filtering liquids.

Such cartridge filters are used in various ways, such as filtration of purified water used in the pharmaceutical industry, electronic industry and the like, filtration in the production process of alcoholic beverages in the food industry, and filtration of coating agents in the automobile industry. It is used in various fields. Conventionally, as a cartridge filter used in the above-mentioned field, a conventional spun yarn, woolen yarn or sino yarn wound around a porous core cylinder described in Japanese Utility Model Laid-Open No. 61-121922.
Alternatively, there is one in which a wide non-woven fabric sheet is simply wound as described in JP-B-1-53565.

As a water purifier for drinking water, a representative example is a fiber activated carbon in a felt shape as described in JP-A-1-304095.

[0005]

However, the conventional spun yarn or woolen yarn wound around to form a filtration layer is
Although the manufacturing cost is low, since the filtrate mainly passes through a relatively large void passage between the thread lattices, it is not suitable for highly accurate filtration and the initial filtration efficiency is not good. In addition, there is a limit to what is possible to improve the filtration accuracy to some extent by increasing the winding density in the case where the non-woven fabric is wound in a roll shape with a wide width, and there is obtained one that can sufficiently satisfy high-precision filtration. Absent. Moreover, these two types of cartridge filters only remove particles in the liquid, and cannot remove residual chlorine in the liquid.

The filter cloth used in the above-mentioned water purifier can remove residual chlorine, but has a short filtration life, and activated carbon fibers may fall off during filtration and be mixed into purified water.

[0007]

According to the present invention, residual chlorine is adsorbed and removed by utilizing the anion adsorption action of an amide bond of a polyamide component, and the polyamide component is made into an ultrafine fiber having a flat cross section. The above-mentioned problem is solved by using the above as a filter layer, wherein a single filter fineness of 0.5 denier is obtained by using a tubular filter layer formed on a porous core tube or a fiber molding core tube of a cartridge filter. The following ultrafine fibers are contained in an amount of at least 50% by weight and at least 30% by weight of the ultrafine fibers are formed by polyamide ultrafine fibers, and the fiber density of the filtration layer is 0.18 to
The feature is that it is set to 0.35 g / cm ³ .

Examples of the porous core tube applicable to the present invention include plastics such as polypropylene, and perforated cylindrical molded articles made of metal, ceramics, etc. Molded articles are preferred. The size and shape may be made according to the size and type of the filtering device, and the size of the holes is not particularly limited, and may be, for example, a large number of square holes each having a side of 3 to 5 mm.

The fiber-molded core cylinder can be obtained, for example, by winding a fiber web containing a heat-adhesive component on a core material while heating. Examples of the fiber containing a heat-adhesive component include a heat-adhesive single fiber, a heat-adhesive composite fiber such as a parallel type or a core-sheath type, a split type, and a sea-island type, and the like. The fibers can be used alone or in the form of a mixture of a heat-bonding single fiber or a heat-bonding composite fiber and a non-heat-bonding fiber, in a molded core tube. The melting point of the high melting point component of the heat-adhesive conjugate fiber or the non-heat-adhesive fiber component is
It is preferably higher than the melting point of the low melting point component of the heat-adhesive conjugate fiber or the heat-adhesive single fiber component by 20 ° C. or more.

As the fiber component forming the fiber-molded core tube, a high melting point component of the heat-bonding composite fiber, a non-heat-bonding fiber component such as cotton, hemp or other natural fiber, rayon or other semi-synthetic fiber, polyolefin, Polyester, synthetic fiber such as polyamide, low melting point component of heat-adhesive composite fiber, polyolefin which is a heat-adhesive single fiber component, polyester, may be appropriately selected from synthetic fibers such as polyamide, composed of the above fiber component The fiber containing the heat-adhesive component is made into a card web by a card machine, and the low-melting point component of the heat-adhesive composite fiber, the low-melting point component such as the heat-adhesive single fiber component or the like, the heat-adhesive composite A high melting point component of the fiber, a method of winding around a cylinder while heating below the melting point which is a high melting point component such as a non-heat-adhesive fiber component, or a heat-adhesive component composed of the fiber component Filling the fiber I in a cylindrical container and a method of heating the molding at the temperature. Here, it is preferable to use polyamide fibers for at least a part of the fibers forming the fiber-molded core cylinder, and most preferable are, for example, composite fibers composed of a combination of normal polyamide and low-melting polyamide, and all polyamide fibers by blending of single components. Is to use.

50% by weight of ultrafine fibers having a density of at least 0.5 denier on the porous core tube or the fiber molding core tube.
As described above, a filtration layer is formed by winding a nonwoven fabric containing polyamide ultrafine fibers in an amount of 30% by weight or more in the ultrafine fibers, and the cartridge filter of the present invention is obtained. At this time,
The nonwoven fabrics may be heat-bonded with polyamide ultrafine fibers, other ultrafine fibers or other fibers.

The polyamide ultrafine fibers having a denier of 0.5 or less forming the above-mentioned filtration layer can be obtained by dividing the splittable conjugate fiber. Examples of the splittable conjugate fiber include combinations of polyamide / polyolefin, polyamide / polyester and the like. As the polyamide, for example, polymers or copolymers of nylon 6, nylon 6,6, nylon 6,10, nylon 11, nylon 12, etc., and as the polyester, polymers or copolymers of polyethylene terephthalate, polybutylene terephthalate, etc. As the polyolefin, a polymer or copolymer such as polyethylene, polypropylene, polymethylpentene, ethylene-propylene copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer may be used. The shape of the fiber cross section of the splittable conjugate fiber can be variously considered and is not particularly limited, but the fiber cross section having a radial shape is preferable.

Splittable conjugate fibers in which polyamide components are combined are also preferably applicable. For example, as a combination of aliphatic polyamide components, preferably, the difference in solubility parameter value (SP value δ: Cal ^1/2 , cm ^3/2 ) is 0.8 or more, and the melt surface tension at 265 ° C. (γ: dyne / cm at 265 ° C.) is 13 or more, that is, the difference in the number of methylene groups per amide bond in the polymer constitutional unit is 3 or more, and more preferably 5 or more. For example, nylon 6, nylon 6,6 Homopolymers, copolymers such as Nylon 6,10, Nylon 11, Nylon 12 and modified products thereof, and may be polymer alloys containing these polymers as a sea component, especially nylon 6 / nylon 12 and nylon 6 , 6 / nylon 12 combination is most preferred.

As the combination of the aliphatic polyamide component and the polyamide component containing an aromatic ring, a polyamide component containing an aromatic ring having a repeating unit of a hydrocarbon chain amide-bonded to the aromatic ring via a methylene group and the above Examples thereof include those containing the aliphatic polyamide component described. Various shapes of the fiber cross section of the splittable conjugate fiber are considered,
The fiber cross section is preferably a radial type, though not particularly limited thereto.

Splittable conjugate fibers were melt-extruded using the above components, drawn, and then cut into desired lengths to form staples. This staple is card method, cross layer method,
After forming a web or a nonwoven fabric by a random webber method, a wet papermaking method, a dry or wet heat bonding method, a needle punching method, etc., it is advisable to divide the different components of the composite fiber by a high pressure liquid flow method and to make them finer to form a nonwoven fabric. If the division is not sufficient at this point, the combination of aliphatic polyamide components may be further subjected to treatments such as needle punching treatment, high pressure liquid flow treatment, ultrasonic treatment and the like. Further, a combination of an aliphatic polyamide component / a polyamide component containing an aromatic ring, which is not sufficiently divided, is treated in high-pressure hot water at a temperature of 120 ° C., treated in hot hydrochloric acid at a concentration of 1.5 N or higher at 95 ° C., Treatment in hot hydrogen peroxide at a concentration of 10% by weight at a temperature of 95 ° C., treatment of hot potassium permanganate aqueous solution at a concentration of 0.1 N at a temperature of 95 ° C., treatment of hypochlorous acid aqueous solution at a concentration of 3% at a temperature of 95 ° C., etc. After the chemical treatment, the needle punching treatment, the high pressure liquid flow treatment, the ultrasonic treatment and the like may be further performed. Then, the obtained non-woven fabric may be partially heat-sealed and applied to the filtration layer.

The non-woven fabric thus obtained is substantially 100
It is made of ultrafine fibers in an amount of 0.5% by weight and contains 50% by weight or more of polyamide ultrafine fibers having a denier of 0.5 or less. However, the object of the present invention can be achieved if the filter layer contains 50% by weight or more of ultrafine fibers and 30% by weight of polyamide ultrafine fibers. Therefore, a web obtained by mixing the above-mentioned splittable conjugate fiber containing a polyamide-based component with other fibers may be subjected to a high-pressure water stream treatment to form a nonwoven fabric for a filtration layer. The basis weight of the nonwoven fabric for the filtration layer is 20
˜150 g / m ² is preferred.

If the amount of ultrafine fibers of 0.5 denier or less is less than 50% by weight, improvement in filtration accuracy cannot be expected, and the proportion of polyamide ultrafine fibers decreases, so that the effect of removing residual chlorine becomes low, and practical use cannot be expected. . Also, the basis weight is 20
If it is less than g / m ² , unevenness in the texture of the nonwoven fabric will occur, leading to uneven filtration accuracy, and if the basis weight exceeds 150 g / m ² , it will become bulky, and it will be particularly difficult to seal the end of the final winding.

The nonwoven fabric is wound on the porous core cylinder or the fiber molding core cylinder to form a filtration layer to form a cartridge filter, and the fiber density of the filtration layer is 0.18 to 0.
35 g / cm ³ is preferred. Fiber density is 0.18g / c
If it is less than m ³ , the filtration accuracy is lowered, it becomes difficult to maintain the shape of the filtration layer, and the fiber density is 0.35 g / cm ^3.
If it exceeds, the filtration life will be shortened.

[0019]

The polyamide ultrafine fibers forming the filtration layer of the cartridge filter of the present invention have a large surface area and therefore efficiently adsorb and remove anions such as residual chlorine in aqueous liquid. In addition, it decomposes and removes low-concentration residual chlorine such as tap water during adsorption, eliminating the chlorine odor of drinking water and improving the flavor of drinking water. Further, since it contains 50% by weight or more of ultrafine fibers having a denier of 0.5 or less, it is useful for collecting relatively fine particles and improves filtration accuracy.

[0020]

【Example】

Example 1 A fiber cross section as shown in FIG. 2 (however, 16
Split), nylon 6 as the A component (5), and the B component
Polypropylene was placed as (6), and melt-composite extrusion spinning was performed, followed by drawing and cutting to obtain a split type conjugate fiber (7) having a denier of 3 mm and a length of 51 mm. 100% by weight of this splittable composite fiber (7) was used as a card web with a card machine, and the water pressure was 1
A high-pressure liquid flow treatment was performed twice on the front and back sides at 50 kg / cm ² and a speed of 3 m / min to obtain a nonwoven fabric having a basis weight of 60 g / m ² . 90% of the splittable conjugate fiber (7) in this nonwoven fabric is A
It was divided into component (5) and component B (6) to give ultrafine fibers having a thickness of 0.19 denier.

Next, the above-mentioned non-woven fabric was used, with an outer diameter of 32 mm and a length of 2
It is wound on a 50 mm polypropylene porous core tube (2) until the outer diameter becomes 65 mm, and the fiber density is 0.20 g / c.
A m ³ filter layer (3) was formed to obtain a cylindrical cartridge filter (1) as shown in FIG. 1.

Comparative Example 1 Polyethylene terephthalate and B component were added to the A component (5) of the splittable conjugate fiber of Example 1.
Polypropylene was used in (6), and a nonwoven fabric was formed by the same method as in Example 1 above. This nonwoven fabric was wound on a polypropylene porous core tube (2) until the outer diameter became 65 mm, and the fiber density was increased. Of 0.20 g / cm ³ was formed into a cartridge filter having the same shape as in Example 1.

[Comparative Example 2] Instead of the splittable conjugate fiber of Comparative Example 1, a parallel type conjugate fiber of polypropylene and polyethylene terephthalate was used to form a nonwoven fabric. Wrap up to an outer diameter of 65 mm, and the fiber density is 0.20 g / c
None of the cartridge filters of Example 1 and the same shape to form a filter layer of m ^3.

[Example 2] Nylon 6 was placed as the A component (5) and Nylon 12 was placed as the B component (6) in Fig. 2. After melt-composite extrusion spinning, drawing and cutting were performed, and 3 denier, 51 m were used.
An m-long splittable conjugate fiber (7) was obtained. This split type composite fiber
(7) was used as a card web using 100% by weight of a card, and a high pressure liquid flow treatment was performed three times on the front and back sides at a water pressure of 150 kg / cm ² and a speed of 3 m / min to obtain a nonwoven fabric having a basis weight of 60 g / m ² . 90% of the splittable composite fibers (7) in the non-woven fabric
Was divided into A component (5) and B component (6), resulting in an ultrafine fiber with a thickness of 0.19 denier.

Then, the non-woven fabric was wound around a polypropylene porous core tube (2) having an outer diameter of 32 mm and a length of 250 mm until the outer diameter became 65 mm as in Example 1, and the fiber density was 0.20 g. A filtration layer (3) having a thickness of / cm ³ was formed to obtain a cartridge filter (1) as shown in FIG.

[Example 3] A core-sheath type composite fiber (2 denier, 51 mm long) having nylon 6 as a core component and low melting point nylon as a sheath component was used at a weight of 25 g / m 2.
The card web of No. ² is heat-treated with hot air of 140 ° C. to melt the sheath component, length 35 cm, weight 1.5 k
g, 30 mm diameter iron core with a fiber density of 0.30 g / cm
While pressurizing to become ³ , wind up until it reaches a winding diameter of 55 mm, then cool it and pull out the iron core
(4) was produced.

Next, nylon 1 is used as the A component (5) in FIG.
2 was placed a polyamide component [Brand name: Nylon MXD6, manufactured by Mitsubishi Gas Chemical Co., Inc.] containing an aromatic ring as the B component (6), and after melt-composite extrusion spinning, it was stretched and cut, 3 denier, 51 mm long A splittable conjugate fiber (7) was obtained. Using 100% by weight of this splittable conjugate fiber (7), a card web was formed by a card machine. After needle punching, a concentration of 1.5N was applied for 7 hours in hot hydrochloric acid at 95 ° C., followed by washing with water.
Water pressure 150 kg / cm ² , speed 3 m / min, 3 on each side
A high-pressure liquid stream treatment was performed to obtain a nonwoven fabric having a basis weight of 60 g / m ² . 90% of the splittable conjugate fiber (7) in this nonwoven fabric was split into the A component (5) and the B component (6), resulting in an ultrafine fiber having a thickness of 0.19 denier. Next, the fiber molding core tube
The non-woven fabric is wound on (4) to an outer diameter of 65 mm to form a filter layer (3) having a fiber density of 0.20 g / cm ³ , and a cylindrical cartridge filter as shown in FIG.
(1)

Comparative Example 3 The splittable conjugate fiber of Example 3
Using (7) 100% by weight, liquid flow treatment was performed with a water pressure of 30 kg / cm ² , and the fibers were entangled to form a nonwoven fabric.
Most of the splittable conjugate fibers in this nonwoven fabric were not split and maintained a circular cross section with a thickness of 3 denier. Then, using this non-woven fabric, a fiber molding core tube (4) was obtained in the same manner as in Example 3.
It is wound on the top until the outer diameter becomes 65 mm, and the fiber density is 0.
A 20 g / cm ³ filtration layer was formed to obtain a cartridge filter having the same shape as that of Example 3.

Comparative Example 4 The splittable conjugate fiber of Example 3
(6) 30% by weight, polypropylene fiber (3 denier,
51 mm length) 70% by weight of mixed cotton was made into a card web by a card machine in the same manner as in Example 3, and the water pressure was 150 kg /
cm ^{2 at} a speed of 3 m / min, high pressure liquid flow treatment twice for each of the front and back to form a nonwoven fabric having a basis weight of 60 g / m ² , and then wound on a fiber molding core cylinder in the same manner as in Comparative Example 3 until the outer diameter becomes 65 mm. It was turned to form a filter layer having a fiber density of 0.20 g / cm ³ to form a cartridge filter.

The filtration performance of each of the cartridge filters of Examples 1 to 3 and Comparative Examples 1 to 4 was evaluated. The results are shown in Table 1.

The filtration performance was evaluated by the following method. Filtration life (l): test dust adjusted to a concentration of 200 ppm (JIS class 11, Kanto loam, average particle size 2μ)
The total water flow rate when the water flow pressure for maintaining 10 l / min from the outside of each cartridge filter toward the hollow part while uniformly stirring the suspension of (m) was 2.0 kg / cm ² ( Evaluation is made in l). Initial filtration efficiency (%): 1 l of the above suspension was sampled, the weight of dust after drying was set to A, and 1 minute of clean water after 1 minute from the start of filtration
It is calculated from the formula of initial filtration efficiency (%) = [(A−B) / A] × 100, where 1 is taken and the weight of dust after drying is B. Filtration accuracy (μm): The clean water was sampled, and the diameter of the coarse particles was measured by an ultracentrifugal automatic particle size distribution device (manufactured by Horiba, Ltd.) to obtain the maximum particle size. Residual chlorine removal rate (%): Sodium hypochlorite was added to the water to adjust the water so that the free residual chlorine concentration C was always 2 ± 0.2 ppm, and the sample was cleaned with a cartridge filter for 10 minutes and then cleaned. The free residual chlorine concentration D of water was measured by the ortho-tolidine method, and the removal rate (%) = [(C-
D) / C] × 100.

[0032]

[Table 1]

[0033]

EFFECT OF THE INVENTION Cartridge filter of the present invention (1)
Means that the tubular filtration layer (3) formed on the porous core tube (2) or the fiber molding core tube (4) contains at least 50% by weight of ultrafine fibers having a single fiber fineness of 0.5 denier or less. At least 30% by weight of the ultrafine fibers are polyamide ultrafine fibers, and the fiber density of the filtration layer (3) is 0.18 to 0.3.
Since the filtration layer (3) is 5 g / cm ³ and the filtration layer (3) is an ultrafine fiber and the fiber density of the filtration layer (3) is relatively small,
Not only is it possible to collect fine particles, but it also prevents the filtration life from decreasing and achieves highly accurate filtration of liquids. Furthermore, since polyamide ultrafine fibers with a large surface area are present in the filtration layer (3), anions are efficiently adsorbed, and when used for filtering tap water, residual chlorine is adsorbed and removed without turbidity. It can supply delicious water and is suitable for water purifiers.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view of a cartridge filter of the present invention.

FIG. 2 is a fiber cross-sectional view showing an example of a splittable conjugate fiber.

FIG. 3 is a partial cross-sectional perspective view of a cartridge filter according to another embodiment of the present invention.

[Explanation of symbols]

1 Cartridge filter. 2 Porous core tube. Three
Filtration layer. 4 Fiber molded core tube. 5 A component. 6 B
component. 7 Split type composite fiber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yosuke Takai 877 Furumiya, Harima-cho, Kako-gun, Hyogo Prefecture Daiwa Bow Create Co., Ltd. Harima Institute

Claims (3)

[Claims] 1. A tubular filtration layer formed on a porous core tube or a fiber molding core tube contains at least 50% by weight of ultrafine fibers having a monofilament fineness of 0.5 denier or less. At least 30% by weight is formed of polyamide ultrafine fibers, and the filtration layer has a fiber density of 0.18 to 0.35.
Cartridge filter characterized by being g / cm ³ . 2. The cartridge filter according to claim 1, wherein the ultrafine fibers are composed of an aliphatic polyamide component and an aliphatic polyamide or a polyamide component containing an aromatic ring. 3. The cartridge filter according to claim 1, wherein the fibers forming the fiber-molded core tube contain polyamide fibers.