TWI569951B - Filter material of the filter processing and discount processing equipment - Google Patents

Description

Folding processing method and discount processing device for filter filter material

The present invention relates to a folding processing method and a folding processing device for a filter medium.

In a clean room, a semiconductor manufacturing apparatus, or the like, an air filter unit having a filter medium that allows air to permeate to collect suspended particles is used. As such a filter medium, a HEPA (High Efficiency Particulate Air) grade or a ULPA (Ultra Low Penetration Air) grade filter medium having a high collection rate is used.

The filter media is generally folded back into a corrugated shape by a folding process. For example, as shown in FIG. 3 of Patent Document 1, a folding processing apparatus 500 including a folding machine 520 is disclosed. The folding machine 520 presses the pair of blades 521 against the filter medium 510 from both sides in the thickness direction to perform the folding process of the filter medium 510.

As the filter medium, a porous film containing polytetrafluoroethylene (PTFE) is preferably used. However, the PTFE porous film is easily electrostatically charged, and when the static electricity is discharged, pinholes are formed in the PTFE porous film to cause leakage during use. In order to prevent this leakage, the discount processing apparatus 500 of Patent Document 1 is disclosed. The static electricity remover 530 is disposed on the flow side between the folding machine 520 and the delivery roller and the lower side of the folding machine 520, and the ionization is blown toward the surface of the filter medium 510. The air.

[Advanced technical literature]

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-345320

However, as shown in FIG. 3, even if the static electricity remover 530 is disposed, the pinholes caused by the discharge are confirmed in the filter medium 510 after the folding process.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a folding processing method and a folding processing apparatus which can prevent a filter medium which forms a pinhole by electric discharge.

In order to solve the above problems, the inventors of the present invention have actively studied the results of the pinholes caused by the discharge of the filter medium during the folding process, and it is specified that even after the static electricity of the filter medium is removed, it is supplied to Before the folding machine is in contact with the conveying roller or the platform, etc., the static electricity is caused, or the blades of the folding machine are also electrostatically charged. The reason why the blade of the folding machine has static electricity is that the blade is generally made of metal, but it is coated with a fluororesin or the like on the surface to avoid scratching the filter medium. The present invention is constructed from this point of view.

That is, the present invention provides a method for discounting a filter medium by using a pair of blades against a filter medium from both sides in a thickness direction to perform a process of folding the filter medium by an electrostatic remover. The ionized air is blown from the side of the filter medium toward the end surface of the filter medium and the pair of blades.

Moreover, the present invention provides a folding processing apparatus comprising: a reciprocating type folding machine that presses a pair of blades against a filter medium from both sides in a thickness direction to perform a folding process on the filter medium; and The remover is disposed on a side of the folding machine to blow the ionized air toward the end surface of the filter medium and the pair of blades.

According to the above configuration, it is possible to prevent the pinhole from being formed in the filter medium by the discharge.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, the following description is an example of the present invention, and the present invention is not limited thereto.

Fig. 1 shows a folding processing apparatus 100 according to an embodiment of the present invention. This discount processing apparatus 100 is for continuously producing a discounted product 11 of a predetermined size from the belt-shaped filter medium 10.

Specifically, the filter medium 10 is supplied from the take-up roller 1 formed by winding the filter medium 10 to the folding machine 50. A conveyance roller 2 is disposed between the delivery roller 1 and the folding machine 50 at an appropriate position, and a tension roller for applying tension to the filter medium 10 is disposed between the specific conveyance rollers 2.

In the present embodiment, a perforation cutter 3 for forming a folding line corresponding to the size of the folded product 11 in the filter medium 10 is provided above the transport roller 2 on the most downstream side.

The folding machine 50 is a reciprocating type in which the pair of blades 5 are reciprocated in the thickness direction of the filter medium 10 (in the vertical direction in the present embodiment). Again, hit The folding machine 50 presses the pair of blades 5 from both sides in the thickness direction against the supplied filter medium 10 to perform the folding process of the filter medium 10.

The filter medium 10 that has been subjected to the folding process is heated by the heater 4 disposed above and below the filter medium 10, and then the shape is trimmed by the counter. Finally, the filter medium 10 is cut by a cross cutter 7 along a folding line formed by the folding line cutter 3.

As the filter medium 10, the particle collection efficiency of the particle diameter of 0.1 μm or more is 50% or more (preferably 90% or more) and the pressure loss is 20 Pa or more under the condition that the filter medium has a wind speed of 5.3 cm/sec. A filter material of preferably 500 Pa or more and 500 Pa or less is suitable for use in an air filter. For example, the filter medium 10 is a laminate of a porous PTFE membrane and an air permeable support material.

The PTFE porous membrane is produced, for example, in the following manner. First, a sheet-like formed body is obtained by adding a PTFE fine powder to a mixture of liquid lubricants by at least one of an extrusion method or a calendering method to form a sheet extending in a predetermined direction. Next, the liquid lubricant is removed from the sheet-shaped formed body by a heating method or a suction method to dry the sheet-shaped formed body. Thereafter, the sheet-like formed body from which the liquid lubricant is removed is extended in the longitudinal direction and the broad side direction.

Further, the PTFE porous membrane may be subjected to oil repellency treatment. This oil-repellent treatment can be carried out, for example, by applying an oil-repellent agent containing a substance having a small surface tension to a porous PTFE membrane and drying it.

The ventilating support material achieves the effect of ensuring the strength of the filter medium 10. The material, structure, and form of the air permeable support material are not particularly limited. However, in the air permeable support material, a material superior in air permeability to the PTFE porous film can be used. For example, a nonwoven fabric, a mesh (mesh mesh), and other porous materials can be used. quality material. However, from the viewpoint of strength, trapping property, flexibility, and workability, it is preferably non-woven. Further, as a material of the air permeable supporting material, for example, polyene (polyethylene (PE), polypropylene (PP), etc.), polyamine, polyester (polyethylene terephthalate (PET), etc.) can be used. , aromatic polyamine or such composite materials.

The method of joining the PTFE porous membrane to the vent support material is not particularly limited, and a method such as an adhesive laminate, a hot laminate, heat welding, ultrasonic welding, or adhesion of an adhesive can be used.

Further, in the folding processing apparatus 100 of the present embodiment, a configuration for preventing pinholes caused by discharge of the filter medium 10 during the folding process is employed. Specifically, as shown in FIG. 2, the static electricity remover 30 is disposed on the side of the folding machine 50. In the present embodiment, the static electricity remover 30 is disposed on both sides of the folding machine 50. However, the static electricity remover 30 may be disposed only on one side of the folding machine 50 depending on the width of the filter medium 10.

The static electricity remover 30 is directed toward the end surface in the width direction of the filter medium 10 and the pair of blades 5 to blow the ionized air so that the wind can directly contact the blade 5. Since the ionized air contains positive ions and negative ions, it is most suitable for preventing electrostatic discharge between the filter medium 10 and the blades 5.

The static remover 30 preferably blows ionized air at any time. The discharge of static electricity is generated when the blade 5 is close to the filter medium 10 to some extent, but this state is not only when the blade 5 separated from the filter medium 10 approaches the filter medium 10 (that is, the front end of the blade 5 and the filter medium) The discharge between 10) is also produced as the blade 5 squeezes the filter media 10 (i.e., the discharge between the side of the blade 5 and the filter media 10).

As described above, in the folding processing apparatus 100 of the present embodiment, since the filter medium 10 and the vane 5 are not simultaneously charged during the folding process, it is possible to prevent the filter medium 10 from forming a pinhole by the discharge.

Example

The embodiments of the present invention are described below, but the present invention is not limited to the following examples.

(Example 1)

As a filter medium, when the filter medium has a wind speed of 5.3 cm/sec, the collection efficiency of particles having a particle diameter of 0.1 μm or more is 99.9999% or more, and the pressure loss is 50 Pa or more and 500 Pa or less is suitable for air filtration. Filter filter material.

The folding processing device is configured as shown in FIG. 1 and FIG. 2, and the electrostatic cleaner removes the ionized air from the side of the filter medium toward the end surface of the filter medium and the pair of blades. Filter material, 10 samples were made as a discounted product. In addition, the discount processing conditions were a discount rate of 62 fold/min, and the heater temperature disposed behind the blade was 80 °C. Further, as the static electricity remover, an ion nozzle (MODEL NIH-55) manufactured by Kasuga Electric Co., Ltd. was used.

(Comparative Example 1)

Ten samples were produced in the same manner as in Example 1 except that the position of the static electricity remover was changed to the upstream side of the folding machine to blow the ionized air from above toward the surface of the filter medium.

(assessment)

The collection efficiency was measured for the samples of Example 1 and Comparative Example 1 (filter filter after the discount processing). Specifically, the speed of the air passing through the filter medium (100 cm ^{2 in} plan view) was adjusted to 5.3 cm/sec, and on the upstream side of the filter medium, polydisperse dioctyl phthalate (DOP) particles were made at 10 ⁷ / Supply in the form of liters. The concentration of DOP particles in the air on the upstream side and the concentration of DOP particles in the air on the downstream side after the filter medium was permeated were measured by a particle counter, and the collection efficiency was calculated based on the following formula. The particle diameter of the DOP particles is set to be 0.1 μm to 0.2 μm.

Collection efficiency (%) = [1 - (downstream concentration / upstream concentration)] × 100

As a result of the measurement of the above-described collection efficiency, it was determined that the sample having a collection efficiency of 99.9999% or more was not leaked, and there was a leak.

Next, for one of the samples determined to be non-leaked, the transmittance (%) is obtained from the formula of "100-capture efficiency (%)", and the formula of "-Log (transmittance (%)/100)" is obtained. The evaluation value is out. That is, a higher evaluation value indicates that the collection efficiency is also high. In addition, the estimated value of the filter media before the discount processing was 7.08.

The results of the leaks and the evaluation values are shown in Table 1.

As shown in Table 1, in Comparative Example 1 in which only ionized air was blown toward the surface of the filter medium before the folding process, four of the ten samples were leaked. This means that the probability of forming a pinhole is very high. Relative to this, In Example 1 in which the ionized air was blown to the end faces of the filter medium and the pair of blades, no pinholes were formed and the entire sample did not leak.

Further, in Example 1, the collection efficiency was higher than that of Comparative Example 1. The reason for this is presumed to be that the relationship between the occurrence of minute pinholes is suppressed.

5‧‧‧ leaves

10‧‧‧Filter filter

30‧‧‧Static remover

50‧‧‧Discounting machine

100‧‧‧ discount processing device

Fig. 1 is a view showing the configuration of a folding processing apparatus according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing the configuration of the vicinity of the folding machine of the folding processing apparatus shown in Fig. 1.

Fig. 3 is a view showing the construction of a conventional folding processing apparatus.

5‧‧‧ leaves

10‧‧‧Filter filter

30‧‧‧Static remover

Claims (3)

A method for processing a filter medium, characterized in that a pair of blades coated with a fluororesin are pressed against a filter medium from both sides in a thickness direction to perform a process of folding the filter medium by electrostatic The remover blows ionized air from a side of the filter medium toward an end surface of the filter medium and the pair of blades. The method for processing a filter medium according to the first aspect of the invention, wherein the filter medium comprises a porous polytetrafluoroethylene film and a permeable support material. A discount processing apparatus comprising: a reciprocating type folding machine that presses a pair of blades coated with a fluororesin against a filter medium from both sides in a thickness direction to perform a folding process on the filter medium; and static electricity The remover is disposed on a side of the folding machine to blow the ionized air toward the end surface of the filter medium and the pair of blades.