JPH01297113A - Nonwoven fabric rolled-in lamination-type cartridge filter and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a cartridge filter with low resistance, high particle-capturing efficiency, long filtering life and high cleanliness by rolling nonwoven cloth of fine fiber diameter characteristic of low-density unevenness and irregular fiber diameter distribution in the form of a cylinder and laminating these clothes. CONSTITUTION:Nonwoven cloth is made of fiber, with an average fiber diameter of 0.5-50mum and an apparent density of 0.03-0.2g/cm<2>, which is manufactured by melt-blow processor jet spinning process, and besides, with a cylindrical core 1 around which the nonwoven cloth is wound, of the average fiber diameter and mean pore diameter becoming larger toward the outside. This nonwoven cloth 2 is wound around the cylindrical core a plurality of times to obtain the subject filter. The materials used for the nonwoven cloth are thermoplastic resins such as polyolefine. This filter is characteristic of low resistance, high particle-capturing efficiency, long filtering life and high cleanliness.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a cartridge filter for filtration used to remove solid matter from a liquid, and in particular to a laminated cartridge filter wrapped in nonwoven fabric and a method for manufacturing the same. .

(Prior Art and its Problems) As a cartridge filter for filtering particulates in a liquid, there are known cartridge filters in which thread, string, paper, nonwoven fabric, etc. are molded into a porous cylindrical shape. However, these have performance disadvantages such as high resistance, inability to obtain a sufficient flow rate, poor filtration accuracy, and short filtration life, and improvements have been desired. In addition, in the case of cartridge filters that use binders or adhesives, detached materials,
Polypropylene wind cartridge filters, which are said to have a large amount of eluted material and do not use binders or adhesives, have the disadvantage of leaching as they use oil when spinning or twisting the yarn, so improvement is desired. It was rare.

(Means for Solving the Problems) In order to overcome these drawbacks, the inventors of the present invention have conducted extensive research, and as a result, have developed a fine fiber diameter nonwoven fabric with uneven density and fiber diameter distribution in a tube-wound shape. The present invention was completed by winding and laminating.

That is, the present invention is made of fibers having an average fiber diameter of 0.5 to 50-1 and an average apparent density of 0.03 to 0.2 g/cut made by a melt blow process or a jet spinning process, The further outward the average fiber diameter,
The present invention is characterized by a nonwoven fabric wound laminated type cartridge filter, which is formed by winding multiple layers of nonwoven fabric configured to have a large average pore diameter.

The nonwoven fabric used in the cartridge filter of the present invention is formed by spraying the fiber stream between a pair of driving rolls in a melt blowing process or a jet spinning process.

By accumulating a high-speed fiber flow between rolls with a slower speed, the fiber flow is forced into a narrow gap, and the long fibers intertwined in the cross section of the nonwoven fabric are laminated across the thickness direction. A nonwoven fabric with uneven density can be obtained. Furthermore, the distance between the spinning orifice and the roll is 20
By carrying out the process in the range of ~80 cm, a more non-uniform product can be obtained in terms of fiber entanglement and fiber diameter distribution. The greater the distance, the greater the turbulence in the fiber flow and the greater the fiber entanglement, resulting in a more uneven fiber assembly and a broader fiber diameter distribution. The preferred distance is 20-80 cm.
A non-woven fabric with extremely brittle and hard fiber adhesion, which is less than Qcta, is obtained, resulting in poor processing and filtration performance (fast clogging).
Undesirable. Furthermore, even if the distance exceeds 80 cm, the effect of non-uniformity hardly changes.

The same effect can be obtained whether the accumulating device is used between a pair of rolls, between a pair of conveyors, or between a roll and a conveyor.

The fiber flow and the speed of the rolls, the distance between the rolls, the shape of the rolls, and the accumulation angle (spraying angle) can be set arbitrarily and are not particularly limited.

Furthermore, in order to quantitatively express the "unevenness in density" and "fiber diameter distribution" of the nonwoven fabric used in the present invention, the concepts of "thickness ratio" and "fiber diameter ratio" were used, respectively.

The thickness was measured using a micrometer at any position in the width direction during the production of the nonwoven fabric, at equal intervals (10 cylinder intervals) in the flow direction.

To measure the fiber diameter, draw straight lines vertically and horizontally at equal intervals (10+nm intervals) on the electron micrograph of the nonwoven filter medium to be measured, and calculate the diameter of the fibers that intersect with each line by 1/100.
Measure with a caliper with an accuracy of mm, and measure the fiber diameter from the photographic magnification.

These nonwoven fabrics are wound from the inner layer around the porous core so that the outer layer of the porous core has larger fiber diameters and pore diameters, and the laminated cartridge filter has a layered structure. Low liquid resistance, large flow rate, pre-filtration effect from the outer layer, and long filtration life. In addition, since it is wrapped in a nonwoven fabric with a predetermined pore size, the filtration accuracy is accurate, there are few separated fibers, and since no oil is used in manufacturing the nonwoven fabric, there is little elution. Thermoplastic resins such as polyolefin, polyamide, and polyester are used as raw materials for nonwoven fabrics. When polypropylene resin is used together with a porous core, it features an all-polypropylene resin cartridge filter, and since no binders or adhesives are used, there are no problems with chemical resistance or leachables. In addition, it can be sterilized in an autoclave, and can withstand normal temperatures of 90°C, making it excellent in terms of food hygiene. The structure of the cartridge filter of the present invention is explained as follows.
~ Shown in Figure 3. In the figure, 1 is a porous core, 2 is a nonwoven fabric (filter material), 3 is an end cap, and 4 is a porous mesh tube.

Therefore, in FIGS. 1 and 2, from the inner layer to the porous core 1, the fiber diameter and pore diameter become larger toward the outside of the cylinder.
This is a filter body in which a nonwoven fabric 2 is wound.

Fig. 3 is a partially cutaway perspective view of a cartridge filter, in which a nonwoven fabric 2 is wound around a porous core 1, and a porous mesh tube 4 made of polypropylene resin is arranged outside to protect the filter medium, and an end made of polypropylene resin is arranged. The caps are completely welded to both ends of the cartridge filter using a heat melting method.

The cartridge filter according to the present invention is installed in a filter housing and allows the medium to be filtered to permeate from the external porous mesh cylinder 4 through the filter medium to the internal porous core 1, thereby removing fine particles and microorganisms in the liquid. Because it can be removed efficiently, it is suitable for use in the filtration of pure water, solvents, and chemicals in the electronics field, and in the filtration of process water, solvents, and intermediate products in the pharmaceutical and cosmetic industries.

Hereinafter, specific examples of the present invention will be illustrated by way of Examples.

Example basis weight 70-90 g/cut, thickness 600-900 μm, density 0.08-0.13 g/cut, thickness ratio J0.
59 to 0.79, and five types of filter media with different average fiber diameters and average pore diameters among polypropylene nonwoven fabrics manufactured by a melt blow process within the physical property value range of "fiber diameter ratio" 1.5 to 3.0. A filter medium having a larger average fiber diameter and average pore diameter was wound four times each toward the outside of the cylinder, and a total amount of 0.8 m2 of five types was wound to prepare a cartridge filter. Table 1 shows the fiber diameters and pore diameters of the five types of filter media.

Table 1 Tables 2.3 and 4.5 show data on water flow resistance, capture efficiency, filtration life, and eluate of the cartridge filters of Examples.

Comparative Example-1 Commercially available polypropylene wind cartridge (nominal 1
Tables 2.3 and 4.5 show the water flow resistance, capture efficiency, filtration life, and eluate of 0fm).

Comparative Example-2 Table 2.3.4.5 shows the water flow resistance, capture efficiency, filtration life, and eluate of a commercially available binder-free cartridge filter (nominally 10 μm) with an integral structure using heat-adhesive fibers.

According to Tables 2.3 and 4.5, the example is comparative example -1°-2
It can be seen that it has higher efficiency, lower resistance, longer life, superior filtration performance, less eluate, and superior cleanliness compared to the conventional method.

(JIS 8 type capture efficiency by filtration of dispersion water) (JIS 8
Lifespan due to filtration of seed-dispersed water) (Effects of the invention) According to the present invention, it is possible to provide a cartridge filter that has low resistance, high particle capture efficiency, long filtration life, and is rich in cleanliness. can.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are manufacturing explanatory diagrams of an embodiment of the present invention;
FIG. 3 is a partially cutaway perspective view of the cartridge filter obtained thereby. Figure 1 Figure 2

Claims (5)

[Claims] (1) Consists of fibers made by melt-blowing process or jet-spinning process with an average fiber diameter of 0.5 to 50 μm and an average apparent density of 0.03 to 0.2 g/cm^3, and becomes the outside of the cylinder to be wound. 1. A laminated cartridge filter wrapped in nonwoven fabric, characterized in that it is formed by winding multiple layers of nonwoven fabric configured to have a larger average fiber diameter and larger average pore diameter. (2) The nonwoven fabric has a thickness ratio of 0.4 or more and a fiber diameter ratio of 1.5.
The cartridge filter according to claim 1, wherein the cartridge filter is as follows. (3) The cartridge filter according to claim 1, characterized in that the nonwoven fabric is wound in a cylindrical shape around a porous core around which a coarse sheet-like porous material has been wound in advance. (4) The cartridge filter according to claim 1, wherein the nonwoven fabric is a thermoplastic resin. (5) Fibers spun by a melt-blowing process or a jet-spinning process are spun between a pair of rolls with a rotation speed slower than the fiber flow, or between a pair of conveyors, with the distance between the spinning orifice and the accumulating device being 20 to 80 cm. To,
2. The method for manufacturing a cartridge filter according to claim 1, wherein the nonwoven fabric is accumulated between the roll and the conveyor, and the nonwoven fabric is wound.