JP3178491B2 - Filter and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter made of a pleated filter medium and a method for producing the filter.

[0002]

2. Description of the Related Art It is widely practiced to remove dust by passing air or other fluid through a filter medium obtained by pleating (pleating) a nonwoven fabric or other filter material. The fold of the filter material is to maximize the filtration area corresponding to the passing fluid as much as possible. For this purpose, it is desirable that the density and height of the folds be as large as possible.

[0003] However, when the density and height of the folds are increased, the folds are bent by the pressure of the passing fluid, so that the folds are easily brought into contact with each other. When the pleats are in contact with each other, the filtration area of the filter medium decreases, the air permeability decreases, and the pressure loss increases, so various measures have been used to prevent the pleats from contacting each other. . For example, the hot melt solidified between the folds and folds of the filter material after the folds, after applying the hot melt resin continuously in a direction crossing the folding line to the filter material before the folds and then applying the hot melt resin in a linear manner. It has been practiced to interpose a melt resin, thereby preventing the folding of the pleats.

However, since the fold-folding process must be performed after the hot-melt resin has been solidified to a certain extent, the resin may be broken or peeled off at the bending point during folding, or the ridges and valleys of the folds may not be formed. May be rounded without being bent as shown in the above. For this reason, it is troublesome to precisely adjust the timing of the bending or to perform the bending while blowing hot air, and it is difficult to perform a completely ordered bending. Therefore, it has been attempted to apply a hot melt resin intermittently in a linear shape so that the resin does not intervene inside the bent portion (the inside of the top of the peak or the valley). This method can improve the easiness of bending to some extent, but it is difficult to accurately perform intermittent coating because of the high viscosity of the hot melt resin. Have difficulty.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a foamable resin is used as a hot melt resin to be linearly applied to a filter medium, and a filter material is formed between folds and folds of the filter medium. A flexible and resilient foamed resin is interposed.

For example, a gas for foaming (for example, nitrogen gas) is mixed into a hot melt resin in a contact state to form a foamable resin, which is continuously applied to a filter material in a linear shape and then folded. When the filter medium is formed, a filter medium having a foamed resin interposed between the folds of the filter medium is obtained.

The resin material may be any material that can be used as a hot melt resin and can impart foaming properties. However, from the viewpoints of fineness after foaming, adhesive strength, durability and the like, polyolefins are used. It is preferable to use a system resin. The expansion ratio of the resin is desirably about 2 to 4 times. If the expansion ratio is too small, it is easy to show the same defects as the conventional technology using a resin that does not foam, and if the expansion ratio is too large, the line will not be uniform, or the compression resistance of the resin after folding will be too small. There is a possibility that the function as a separator between the folds cannot be performed.

The application of the resin to the filter medium is desirably a continuous linear application from the viewpoint of the efficiency of the application operation . When a continuous line is applied, the application speed becomes remarkably high , and
Linear application becomes easy. Furthermore , even when the height of the fold of the filter medium is very low (for example, 10 mm or less), it can be easily applied. Linear deposition is performed on both sides of the filter media.
In addition , it may be linear or wavy, and it is desirable that the application lines on both the front and back sides are located at positions facing each other. If the lines on both the front and back surfaces are significantly displaced, there is a possibility that unnecessary undulations may occur in the folded fold filter medium after the production.

[0009]

[Function] Since the foamable hot melt resin linearly adhered to the surface of the filter medium has a flexible elasticity even after solidification, the bending resistance at the time of folding the filter medium is small, and the bending is also performed. The linear resin located outside the location extends greatly along the ridge, and the linear resin located inside the location is compressed and reduced. Therefore, the filter medium can be sharply bent, and the adhered resin elastically and firmly adheres to the filter medium, so that the resin does not break or peel off. In addition, since the bending is facilitated and the adhesion of the resin is good, the operation at the time of bending, particularly during the manufacturing, is facilitated, and a very pleated arrangement can be obtained.

[0010]

EXAMPLE A nonwoven polypropylene nonwoven fabric having a fiber diameter of 10 μm or less produced by laminating a web made of acrylic fiber and polyclar fiber having a fineness of 2 denier with a polyvinylidene chloride adhesive and further laminating by a melt blow method was used as a filter medium. After a pleating line for pleats having a width of about 20 mm was formed on the filter medium 1, a polyolefin resin melted at 180 ° C. (having a melting point of 180 ° C.) was formed on both sides thereof.
The foaming resins 2 and 3 (foaming ratio was set to about 2.5 times) obtained by adding a foaming property by mixing nitrogen gas into the resin were mixed with a width of about 1.
It was applied continuously in a 5 mm line.

The melting of the resin, the mixing of nitrogen gas, and the application on the filter medium are performed using a Nordson foam melt adapter modified so as to conform to the practice of the present invention. It was applied so as to be located at a position facing the substrate. After the resin is foamed and solidified to the extent that it loses fluidity, the filter medium 1 having the foamed resins 2 and 3 attached on both sides in a linear manner has a pleated height of about 20 mm and an interval of the pleated peak 4 of about 4 mm The filter A was pleated as described above.

As shown in the partial perspective view of FIG. 1 and the cross-sectional view of FIG.
The pleated peaks 4 and valleys 5 are formed in a very orderly state, the folds are not rounded at the portion where the resin is applied, and at the time of pleating, the flexible resin after foaming is still The resin on both sides of the valley of the pleats is pressed against each other in a soft state and deforms and adheres to each other because some viscosity remains, which contributes to maintaining the pleat spacing and aligning the pleats. Admitted.

The above-mentioned filter was adhered and fixed in a filter frame using a urethane-based adhesive. The filter was mounted on an air conditioner, used for three months, taken out, and the state of the pleat was observed. Did not come into contact with each other and the applied resin did not peel off, and it was confirmed that an orderly pleat state was maintained.

[0014]

According to the present invention, a flexible and resilient foamable resin is used as the resin applied linearly to the surface of the filter medium of the pleated filter in order to maintain the interval between the pleats of the filter medium. Therefore, when the filter media is folded, the peaks and valleys of the pleats do not look round,
An efficient and beautiful pleated filter in which the pleats are arranged in an orderly manner can be obtained, and the solidified resin can be maintained in an orderly and pleated state for a long time without breaking or peeling. Further, by using the foaming resin, it is possible to reduce the amount of the resin, reduce the weight of the filter, and the like, and to improve the productivity by eliminating the cumbersomeness in manufacturing when using a normal resin. be able to.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a filter of the present invention.

FIG. 2 is a sectional view of an example of the filter of the present invention.

FIG. 3 is a conceptual diagram showing a process flow of a filter manufacturing method of the present invention.

[Explanation of symbols]

 A Filter 1 Filter medium 2 Foam resin on the front side of filter medium 3 Foam resin on the back side of filter medium 4 Pleated ridges 5 Pleated valleys

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-32712 (JP, A) JP-A-61-74618 (JP, A) JP-B-54-30144 (JP, B2) JP-B-60-60 4228 (JP, B2) JP 4-16227 (JP, B2)

Claims (3)

(57) [Claims] 1. A gas is mixed with a hot melt resin in a molten state.
Into a foaming resin with a foaming ratio of about 2 to 4 times,
This is applied to both sides of the filter media with fold lines at predetermined intervals,
After applying continuously linearly in the direction crossing the fold line, filter
Pleated by bending the material in a wavy shape along the fold line
Performed and solidified linear foam resin pleated and pleated
And a method for manufacturing a filter. 2. The filter medium is folded along a fold line.
With a large number of pleats
Between the pleating and pleats in a direction crossing the fold line of the filter media
With a foaming ratio of 2 to 4 times
A foamed resin consisting of a melt resin is interposed.
Item 7. A filter manufactured by the method according to Item 1. 3. A foamed resin is provided on both sides of the filter medium via the filter medium.
3. The coating is applied at positions substantially opposite to each other.
The filter described.