JPH0445810A - Cartridge filter - Google Patents

Abstract

PURPOSE:To improve the filter preciseness without lowering the life by winding the slit nonwoven fabric consisting of the conjugate fiber in which the specified ratio of constituent fibers is devided into under specified denier on a porous core tube to form a filter layer so as to have a specified fiber density. CONSTITUTION:The slit nonwoven fabric 3 consisting of the conjugated fiber in which >=10wt.% of the constituent fibers is devided into <=0.5 denier is wound on the porous core tube 4 to form the filter layer 2, and the fiber density of the filter layer 2 is made to be 0.18-0.30(g/cm<2>). As a result, fine numerous uniform clearance passages are formed so that the particles of fine particle diameter are precisely caught, and the filter preciseness is improved without the lowing of filter life.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cartridge type filter using fiber as a constituent component.

[Prior Art] Cartridge-type filters using fibers as a constituent are mainly useful for filtering liquids. In particular, filtration of purified water used in the pharmaceutical industry, electronic industry, etc., or filtration in the manufacturing process of alcoholic beverages in the food industry,
Furthermore, it is used in various fields such as filtration of paint agents in the automobile industry.

Conventional cartridge filters of this type include those in which ordinary spun yarn, woolen yarn, or Zino yarn is wound around a porous core described in Japanese Utility Model Publication No. 121922/1983, or the one described in Japanese Patent Publication No. 1-53565. As stated,
Some are simply wrapped with wide sheets of non-woven fabric.

[Problem to be solved by the invention] However, although the production cost is low when ordinary spun yarn or woolen yarn is wound around a porous core, on the other hand, the filtrate is mainly absorbed by the relative There is a problem that 1- is unsuitable for high-precision filtration because it passes through a large gap passage. In addition, there is a problem that the initial filtration efficiency is not good.

In addition, in the case of non-woven fabric wound in a wide width, the outermost layer of the filter is flat, so although filtration accuracy can be improved to some extent by increasing the winding density, the filtration life is shortened. The problem is that it is short.

In addition, in boat fishing, filtration accuracy and filtration life have contradictory properties, and there is also the problem that improving one will inevitably result in a decrease in the other.

In order to solve the problems of the conventional example, an object of the present invention is to provide a cartridge filter that can improve filtration accuracy without significantly reducing the filtration life.

[Means for Solving the Problems] In order to achieve the above object, the cartridge filter of the present invention has a slit nonwoven fabric made of composite fibers in which 10% by weight or more of the constituent fibers are divided into 0°5 denier or less pieces. A filtration layer is formed by being wrapped around the core tube, and the filtration layer has a fiber density of 0.18 to 0.30.
It has the following configuration.

In the configuration of the present invention, the thread width of the slit nonwoven fabric is preferably 3 to 30 mm.

Moreover, in the structure of the present invention, it is preferable that the length of wrapping of the slit nonwoven fabric is in the range of 5 to 20 cm per cycle.

The configuration of the present invention will be explained in detail below.

In the present invention, 10% by weight or more of the constituent fibers is 0.5% by weight or more.
The reason for using composite fibers that are divided into denier or smaller pieces is to accurately filter out fine foreign matter having particle diameters on the order of microns (μm).

Next, the reason for using the slit nonwoven fabric is to maintain the appropriate density of the filtration layer, increase the surface area, and maintain a relatively long filtration life.

Next, the reason why the slit nonwoven fabric is wound around the porous core tube to form a filtration layer is to make it into a cartridge type.

Next, the fiber density of the filtration layer is set to 0.18 to 0.30 (g/c
The reason why the range is m+3) is to satisfy both filtration accuracy and filtration life. That is, the density is 0.18
If it is less than 0, the filtration accuracy will decrease, and if it exceeds 0 or 30, the filtration life will tend to decrease.

The thermoplastic polymer used for the fibers constituting the nonwoven fabric is required to have excellent properties required for filtration, that is, generally excellent heat resistance and chemical resistance, such as polyethylene, polypropylene, and poly(4-methylpentene-1). , ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polyester represented by polyethylene terephthalate, polybutylene terephthalate, etc.
Examples include polyamides represented by nylon-6 and nylon-6,6, polyvinyl chloride, and polyvinylidene chloride. These polymers may be appropriately selected depending on the object to be filtered, the purpose of filtration, or the use of the filter, and are not necessarily limited to the above-mentioned polymers.

Among these, polyethylene and polypropylene are particularly preferably used from the viewpoint of non-water absorption and cost.

Furthermore, in the present invention, at least composite fibers are used as the constituent components. As the conjugate fiber, for example, the above-mentioned various conjugate fibers of two or more components can be used.

These composite fibers are made by combining two or more polymers in the same die to prevent melting.
It can be obtained by

An example of the cross section of a few representative two-component composite fibers is shown in the fourth section.
It is shown in Figs. When using these composite fibers, it is best to follow various known methods. For example, in the case of split-type composite fibers, the interface between the composite components is removed by applying physical stress such as high-pressure water. It can be peeled off to form finer fibers. That is, fine denier fibers can be easily obtained from the splittable composite fibers. Such ultra-fine treatment is generally carried out at the same time as the production of the nonwoven fabric or after it is made into a nonwoven fabric, but it is not necessarily limited to this order.

Particularly preferred among the conjugate fibers is a split type conjugate fiber as shown in FIG. 4, and a type that is split into fibers by physical stress from the interface of each component is preferably used. When such a type of conjugate fiber is used, the components constituting the conjugate fiber are not particularly limited as long as they are a combination of the above-mentioned polymers that can be split during the splitting process. Further, in FIGS. 4 and 5, an eight-split composite fiber is shown, but the number of splits can be any number.

In addition, we use components with excellent heat resistance and chemical resistance such as polypropylene, ethylene vinyl alcohol copolymer, and poly 4-methylpentene-1, which are the fibers that make up the skeleton of the nonwoven fabric, as the first component, and polyethylene, etc. as the second component. A combination of heat-fusible components may also be used.

Further, it is a preferable method to mix and use fibers as a binder component (heat-fusible fiber component) as fibers constituting the nonwoven fabric. This is because it not only improves the strength of the slit nonwoven fabric and is expected to improve the efficiency of the winding process, but also reduces the amount of fibers that fall off. As the binder fiber, low melting point polyethylene or ethylene vinyl acetate copolymer is preferably used.

The preferred mixing amount is 5 to 30%, especially 10%
~20% by weight. As a manufacturing method, a partially heat-sealed nonwoven fabric can be produced by uniformly blending binder fibers before forming a nonwoven fabric and heat-treating the fabric after forming the nonwoven fabric.

Regarding the fineness of the fibers, it is best to select the appropriate one depending on the purpose of the filter, such as the purpose of the filter, the object to be filtered, how much of the material needs to be filtered, etc.
Although not particularly limited, those of 1 to 30 deniers, preferably 3 to 10 deniers, are used. When splittable conjugate fibers or other composite fibers are used, the fineness when divided into each component is 0.5 denier or less, preferably 0.05 to 0.5 denier, particularly 0.5 denier or less.
It is 1 to 0.3 denier. In this way, when composite fibers are used in the form of so-called ultrafine fibers that are thinner than ordinary single fibers, they are suitably used as filters that require more precise filtration.

The method for producing fibers, which are raw materials for nonwoven fabrics, is not particularly limited, and typical techniques such as melt extrusion spinning, stretching, and cutting into desired lengths to produce staple fibers can be employed.

A method for producing a nonwoven fabric using the above-mentioned fibers is to apply the fibers to a carding machine to form a carded web, heat-treat it with a hot air processing machine, form it into a sheet with a hot roll machine, or entangle it with a water needle, needle punching machine, etc. Methods such as forming a sheet-like non-woven fabric can be adopted. Among these, nonwoven fabrics produced by the water needling method are particularly preferred because the composite fibers can be effectively split.

Next, the sheet-like nonwoven fabric is cut into a predetermined width to obtain a slit nonwoven fabric. The thread width of the slit nonwoven fabric is preferably 3 to 30 mm, more preferably 5 to 20 mm. 3m
If it is less than 30 mm, it is likely to break during the winding process (and if it exceeds 30 mm, the gap between the overlapping nonwoven fabrics will become larger and the filtration accuracy will tend to decrease.

Moreover, in the structure of the present invention, it is preferable that the length of wrapping of the slit nonwoven fabric is in the range of 5 to 20 cm per cycle. When one cycle (one round) is less than 5 cm, the winding density is too high and it becomes difficult to increase the filtration life, and when it exceeds 20 cm, the filtration accuracy tends to decrease.

When manufacturing the cartridge filter of the present invention, it is preferable to use a slit thread made of a nonwoven fabric before being wound around the core tube, with a basis weight of 20 to 150 g/rrf, particularly preferably 40 to 100 g/rrf. It is. If the mesh size is less than 20g/Po, unevenness will easily occur in the nonwoven fabric, and if the fabric weight is larger than 150g/%, it will become too thick and difficult to wrap tightly.

The slit thread made of the nonwoven fabric thus obtained can be wound onto a porous core tube using a winder to obtain the nonwoven fabric slit thread-wound cartridge filter that is the object of the present invention. Naturally, the method of winding the slitter yarn made of such a nonwoven fabric around the porous core cylinder is not particularly limited as long as the surface of the porous core is completely covered. For example, it is preferable to wind it in a twill pattern.

The gap path may be adjusted by such winding, or may be adjusted to an appropriate gap path by the above-described winding method and number of winds.

Next, the porous core cylinder can be made of any material such as plastic such as polypropylene, metal, or ceramic, but a molded product made of plastic such as polypropylene is preferable from the viewpoint of cost. The size and shape can be made to match the size and type of the filtration device. The size of the hole can be, for example, a rectangle with an angle of 3 to 5 mm.

The thickness of the nonwoven fabric layer wound around the surface of the porous core tube is preferably about 15 to 50 mm, for example.

In addition, in the present invention, 10% by weight or more of the constituent fibers is 0.
．． The filtration layer is formed by winding a slit nonwoven fabric made of composite fibers divided into pieces of 5 deniers or less onto a porous core cylinder, but it is of course possible to add other components.

[Function] The car of the present invention described above! - According to the structure of the ridge filter, 10% by weight or more of the constituent fibers are 0. Since a slit nonwoven fabric made of composite fibers divided into 5 deniers or less is wound and used as the filtration layer, the structure has a well-balanced arrangement of internal voids. As a result, due to the large number of fine and uniform void channels, small particles in the liquid can be captured with high accuracy, and filtration accuracy can be improved without significantly reducing the filtration life.

Further, according to the preferred configuration of the present invention in which the thread width of the slit nonwoven fabric is set to 3 to 30 mm, the winding density can be optimized.

Further, according to the preferred configuration of the present invention in which the length of wrapping of the slit nonwoven fabric is in the range of 5 to 20 cm per cycle, the wrapping density can be optimized as described above.

[Example] Embodiments of the present invention will be described below based on the drawings.

1 to 3 show a cartridge filter according to an embodiment of the present invention. That is, FIG. 1 is an external perspective view of a cartridge filter according to an embodiment of the present invention, FIG. 2 is an enlarged view of the portion A in FIG. 1, and FIG. 3 is a partially cutaway view of FIG. 1.

In FIGS. 1 to 3, 1 is a cartridge filter, 2 is a nonwoven fabric slit yarn layer (filtration layer), 3 is a slit yarn, and 4 is a porous core tube. The slit thread 3 is a porous core tube 4
Since the threads are wound in a twill pattern, the slit threads 3 are arranged three-dimensionally to form unevenness when viewed from the surface as shown in FIG.

Next, FIGS. 4 and 5 are schematic cross-sectional views of split-type composite fibers used in one embodiment of the present invention. That is, composite fiber 5
is composed of at least two fiber components and is separated by physical or chemical means. Note that the fiber components 6 and 7 may be made of the same polymer, and in this case, another polymer may be interposed between each dividing component to facilitate division. The cross section of the splittable composite fiber is the fourth
It is not limited to what is shown in FIGS. 5 and 5, but any type may be used.

Regarding the cartridge filter configured as described above, its function, manufacturing method, etc. will be explained below using experimental examples.

Example 1 A splittable conjugate fiber having the fiber cross section shown in Fig. 4 (divided into 16), with polypropylene as the component 6 in the figure and poly4-methylpentene-1 as the component 7 in the figure, was melted. It was obtained by spinning, stretching and cutting. The obtained composite fiber has a fiber thickness of 3 denier and an average fiber length of 45 m.
It was m.

Using 100% by weight of this composite staple fiber, it was passed through a card machine and opened to form a carded web, and then passed through a water needle (water pressure 45 kg/cur, speed 12 m/mm).
) to produce a sheet-like nonwoven fabric with a basis weight of 58.7 kg/cnr. At this time, the proportion of split 0.18 denier fibers was 65% by weight.

This nonwoven fabric was slit in a width of 10 mm in the longitudinal direction using a slitter to obtain slit yarn 3 shown in FIG.

This slit thread 3 is wound around a polypropylene porous core tube 4 using a winder (100% per cycle).
cm (i.e., 2.5 winds from one end of the porous core tube 4 to the other end) Inner diameter: 30 mm m z
Outer diameter 60mm, length 250mm.

A cartridge filter 1 with a filter layer density of 0.235 g/cm3 was obtained.

Table 1 shows the results of evaluating the filtration performance of the obtained cartridge filter.

At this time, the filtration performance was evaluated as follows.

■ Filtration life: While uniformly stirring a suspension of test dust (Kanto ROHM, average particle size 8 μm) adjusted to a concentration of 2 ooppm, maintain 01/min from the outside of each cartridge filter toward the hollow part. The evaluation is based on the total water flow rate (1) when the water flow pressure is 2.0 kg/ci.

■ Filtration accuracy: Collect the clean water obtained as above, measure the diameter of obscene particles using an ultracentrifugal automatic particle size distribution analyzer (manufactured by Horiba Seisakusho), and evaluate based on the maximum particle diameter (μm). do.

■ Initial filtration efficiency: 1. The dust weight after drying is 8, and the clean water 1 minute after the start of filtration is 1
1 sample and the weight of the dust after drying is calculated using the following formula as B.

Initial filtration efficiency (%) = [(A-B)/A] X10
0 Comparative Example 1 Polypropylene fiber (fiber thickness 3 denier, fiber length 45
1-62 count (S) by ring spinning using
A thread was obtained and wound around a porous core in the same manner as in Example 1 to prepare a cartridge filter.

This comparative example corresponds to the filter described in Japanese Utility Model Application Publication No. 61-121922.

Table 1 shows the filtration performance of the obtained cartridge filter.

Comparative Example 2 Using the wide nonwoven fabric used in Example 1, it was
It was cut into a width of m and wrapped around a porous core tube to make a cartridge filter. This comparative example is
This corresponds to the filter described in Japanese Patent No. 565.

Table 1 shows the filtration performance of the obtained cartridge filter.

As is clear from the Examples and Comparative Examples below, the cartridge filter of this Example has excellent filtration accuracy in that it can filter out even the smallest foreign matter, has excellent initial filtration efficiency, and has a filtration life comparable to Comparative Example 2. It has a remarkable effect of being superior in comparison. Since it is based on non-woven fabric, it has many internal voids (fine and uniform, resulting in excellent filtration accuracy, and by winding a slit thread made of non-woven fabric, a large number of uniform void channels are formed, so the cartridge filter has an improved filtration life. It can be done.

The cartridge filter 6 of the present invention explained above in 1-
It is mainly useful for filtration of liquids, such as filtration of purified water used in the pharmaceutical industry, electronic industry, etc., filtration in the alcoholic beverage manufacturing process in the food industry, and filtration of paint agents in the automobile industry. It can be used or applied in various fields.

[Effects of the Invention] As explained above, according to the cartridge filter of the present invention, 10% by weight or more of the constituent fibers are 0.

Since a slit nonwoven fabric made of composite fibers divided into 5 deniers or less is wound and used as the filtration layer, the structure has a well-balanced arrangement of internal voids. As a result, due to the large number of fine and uniform void channels, it is possible to capture small particles in the liquid with high precision, and the excellent effect of improving filtration accuracy without significantly reducing the filtration life. can be achieved.

Further, according to the preferred configuration of the present invention in which the thread width of the slit nonwoven fabric is set to 3 to 30 mm, the winding density can be optimized.

Further, according to the preferred configuration of the present invention in which the length of wrapping of the slit nonwoven fabric is in the range of 5 to 20 cm per cycle, the wrapping density can be optimized as described above.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a cartridge filter according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG.
The partial cross-sectional views in the figure, FIGS. 4 to 5, show examples of cross-sectional views of composite fibers used in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Cartridge filter, 2... Slit nonwoven fabric layer (filtration layer), 3... Slit nonwoven fabric, 4...
Porous core tube, 5... split type composite fiber, 6.7... fiber component. Patent applicant Daiwabo Create Co., Ltd. 5: Splitable composite fiber 6.7: Fiber components Figure 4 Figure 5

Claims (3)

[Claims] (1) A slit nonwoven fabric made of composite fibers in which 10% by weight or more of the constituent fibers are divided into 0.5 denier or less pieces,
A cartridge filter in which a filtration layer is formed by being wound around a porous core tube, and the filtration layer has a fiber density of 0.18 to 0.30. (2) The cartridge filter according to claim 1, wherein the slit nonwoven fabric has a thread width of 3 to 30 mm. (3) The cartridge filter according to claim 1, wherein the winding length of the slit nonwoven fabric is in the range of 5 to 20 cm per cycle.