JP4736898B2 - Manufacturing method of filter element - Google Patents

Description

  The present invention relates to a method for manufacturing a filter element such as an air filter for an automobile engine.

Conventionally, as a filter element of this type, in Patent Document 1, a melt blow fleece (filter material layer) manufactured by a melt blow method is laminated on the surface of a support layer made of, for example, metal wire woven fabric or cellulose-based filter paper. A bonded two-layer structure has been proposed. The support layer is for stably supporting the filter medium layer, and the filtering action of the support layer is negligible compared to the filter medium layer.
JP 2001-523562 A (see paragraphs 0005 and 0006)

  However, since the conventional filter element employs a method in which both layers are bonded with an adhesive after the support layer and the filter medium layer are manufactured in separate steps, an adhesion step of performing only the adhesion of both layers is necessary. There is a problem that the manufacturing process increases and becomes complicated, and the manufacturing cost cannot be reduced.

  In the conventional filter element, the support layer and the filter medium layer are used only for bonding the two layers and are bonded by an adhesive unnecessary for filtration. There is a problem that a part of the eyes of the filter is blocked, the passage resistance of air to be filtered increases, and high pressure loss occurs. For this reason, when the filter element is used in an air filter of an automobile engine, there arises a problem that the intake resistance of the engine increases and the combustion efficiency decreases.

  The present invention provides a filter element manufacturing method capable of solving the above-described conventional problems, simplifying the manufacturing process, reducing the manufacturing cost, and reducing the pressure loss of the passing fluid. It is in.

In order to solve the above problems, the invention according to claim 1 includes a first step of forming a first filter medium layer by making a slurry in which a first fiber is dispersed in a liquid, and the first filter medium layer. At least one of the first filter medium layer and the second filter medium layer in a wet state, the second step of forming a second filter medium layer comprising second fibers on the upper surface of the first filter layer, and simultaneously with the second process or after the second process. After the third step of removing moisture contained in the first filter medium layer and the third step, both the filter medium layers are impregnated with an adhesive, and the contact portion between the first fibers and the first and second fibers. a fourth step of bonding the contact portion by an adhesive, after said fourth step, seen including a fifth step of drying the first filter layer and second filter layer, removing the moisture, The gist is that the first filter medium layer is dried by heating .

(Function)
In the first aspect of the present invention, after the step of removing moisture contained in the gaps between the first filter media layers, both the filter media layers are impregnated with an adhesive, and the first fiber mutual contact portion and the first fibers The contact portion of the second fiber was adhered with an adhesive. For this reason, in the process of impregnating the first filter medium layer and the second filter medium layer with the adhesive, the first filter medium layer and the second filter medium layer can be joined, and a dedicated bonding process only for bonding both layers is performed. Omitted, the manufacturing process can be simplified, and the manufacturing cost can be reduced. In addition, since there is no adhesive used only to bond the first filter medium layer and the second filter medium layer, the gap near the joint interface between the two layers, that is, the filter eyes are not reduced, and the pressure of the fluid passing through Loss can be suppressed.

  The manufacturing method of the filter element of the present invention can simplify the manufacturing process and reduce the manufacturing cost, and can reduce the pressure loss of the fluid that permeates the manufactured filter element.

The outermost first, with reference to FIG. 1, the structure of the filter element 11. The filter element 11 includes a first filter medium layer 12 and a second filter medium layer 13 laminated and bonded to the upper surface of the first filter medium layer 12. The first filter medium layer 12 has intricately entangled innumerable first fibers 14 having a fiber diameter of 10 to 40 μm and a fiber length of 1 to 4 mm made of pulp, and mutual contact portions of the first fibers 14 are adhesives. 15 and is formed into a nonwoven fabric sheet having a thickness t1 of 0.4 to 0.6 mm as a whole. Innumerable gaps (eyes) g1 through which air passes are formed between the first fibers 14, and the porosity of the first filter medium layer 12 is 85%.

  The second filter medium layer 13 entangles a large number of second fibers 16 made of, for example, polyethylene terephthalate (PET) and having a fiber diameter of 1 to 10 μm, and each second fiber 16 has a contact portion 16a fused to each other. They are integrated and formed as a nonwoven fabric sheet having a thickness t2 of 0.05 to 0.15 mm as a whole. Innumerable gaps (eyes) g2 through which air passes are formed between the second fibers 16, and the porosity of the second filter medium layer 13 is 95%.

  A part of the second fiber 16 enters the gap g <b> 1 in the surface layer portion on the second filter medium layer 13 side, and the second fiber 16 is bonded to the first fiber 14 by the adhesive 15. For this reason, the porosity of the gap g1 in the surface layer portion is reduced to 80% by mixing the first fibers 14 and the second fibers 16.

  The filter element 11 is accommodated in a case (not shown) of an air cleaner such that the second filter medium layer 13 is located on the upstream side of the air flow path and the first filter medium layer 12 is located on the downstream side. When the air to be filtered passes through the filter element 11 as indicated by the arrow in FIG. 1, relatively large dust contained in the air is captured by the gaps (eyes) g <b> 2 of the second filter medium layer 13. Further, fine dust contained in the air is captured by the gap (eyes) g1 of the first filter medium layer 12.

Here, the weight per unit area of the first fibers 14 of the first filter medium layer 12, that is, the basis weight is set to 50 to 200 g / m ^2, and the basis weight of the second fibers 16 of the second filter medium layer 13 is 2 .5 to 20 g / m ² .

Next, based on FIGS. 2-6, the manufacturing method of the filter element 11 comprised as mentioned above is demonstrated.
As shown in FIG. 6, an endless conveyor belt 22 made of a papermaking net is attached to the plurality of pulleys 21 and is circulated at a predetermined speed in the direction of the arrow by a drive mechanism (not shown). . A first filter medium layer forming device (papermaking machine) 23 for forming the wet first filter medium layer 12 on the upper surface of the forward section 22a is provided upstream of the forward section 22a on the upper side of the conveyor belt 22. It is installed. In the container 24 of the first filter medium layer forming device 23, a slurry 25 obtained by mixing and stirring water as a liquid and the first fibers (pulp) 14 is stored. Is supplied to the supply port 27, and the slurry 25 is supplied from the supply port 27 to the upper surface of the forward portion 22 a of the belt 22. By the paper making process as the first process, as shown in FIG. 2, a wet first filter medium layer 12 composed of countless first fibers 14 is formed on the upper surface of the forward portion 22 a of the belt.

  As shown in FIG. 6, a melt blower device 31 is mounted on the downstream side of the first filter material layer forming device 23. The melt blown device 31 spins molten polyethylene terephthalate (thermoplastic resin) from a spinning nozzle 32 and draws a spinning fiber by blowing a high-temperature, high-pressure air stream to the outlet of the nozzle 32. The stretched second fibers 16 are randomly entangled so as to be thinly laminated on the upper surface of the first filter medium layer 12 on the forward portion 22a as shown in FIG. 13 is formed. The innumerable contact portions 16a of the second fibers 16 of the second filter medium layer 13 formed by the second step are fused and connected by the fusing force of the semi-molten fibers themselves.

  As shown in FIG. 6, a suction device 35 is mounted on the downstream side of the melt blown device 31. The suction device 35 includes an air guide 36 for guiding suction air and a suction pump 37. Then, while the forward portion 22a of the belt on which the first filter medium layer 12 and the second filter medium layer 13 are placed passes through the air guide 36, the first filter medium layer 13 through the first filter medium layer 13 as shown by arrows in FIG. An airflow that passes through the filter medium layer 12 and the forward portion (net) 22a is generated. The water impregnated in the first filter medium layer 12 is sucked and removed downward by this air flow. In the third step of sucking and removing moisture by the air flow, as shown in FIG. 4, one of the second fibers 16 of the second filter medium layer 13 is placed in the gap g1 of the first fibers 14 of the upper layer part of the first filter medium layer 12. Part is drawn by the airflow.

  Next, as shown in FIG. 6, the filter element 11 is separated from the upper surface of the conveyor belt 22 by the pulley 21 on the downstream side of the suction device 35, and the filter element 11 is a pair of upper and lower impregnation rollers of the adhesive impregnation device 41. Supplied between 42 and 43. In the fourth step, both the impregnating rollers 42 and 43 are impregnated with a thermosetting adhesive 15 such as phenol resin, and the first filter medium layer 12 is impregnated by the impregnating rollers 42 and 43 as shown in FIG. The adhesive 15 is impregnated in the gap g1 and the gap g2 of the second filter medium layer 13. The impregnated adhesive 15 is attached to the contact portion between the first fibers 14 and the contact portion between the first fiber 14 and the second fiber 16, and the contact portion is bonded by the adhesive 15.

  In the next fifth step, the filter element 11 impregnated with the adhesive 15 is supplied to the drying device 45 as shown in FIG. The filter element 11 is heated and dried by the drying device 45, the adhesive 15 is dried and cured, and the first fibers 14 of the first filter medium layer 12 and the second fibers 16 of the second filter medium layer 13 are shown in FIG. Thus, the filter element 11 is manufactured in a non-woven sheet shape. The filter element 11 is wound around a roll 46 and then cut into a predetermined size according to the purpose of use, and used as a filter element of an air filter, for example.

According to the filter element manufacturing method of the above embodiment, the following effects can be obtained.
(1) In the above embodiment, simultaneously with the step of bonding the contact portions of the first fibers 14 of the first filter medium layer 12 with the adhesive 15, the first fibers 14 of the first filter medium layer 12 and the second fibers The contact portion of the second fiber 16 of the filter medium layer 13 is bonded by the adhesive 15, and the first filter medium layer 12 and the second filter medium layer 13 are bonded. For this reason, after manufacturing the 1st filter medium layer 12 and the 2nd filter medium layer 13 separately, respectively, it is not necessary to adhere | attach both layers by a dedicated adhesion process, and can simplify a manufacturing process.

  (2) In the above embodiment, since there is no surplus adhesive used only for bonding the first filter medium layer 12 and the second filter medium layer 13, there is a gap near the joint interface between the two layers 12, 13, that is, the filter. The eyes do not become small, and the pressure loss of the air passing through the filter can be suppressed. For this reason, in the case of an air filter for an automobile engine, the intake resistance is lowered, and the combustion efficiency can be improved.

  (3) In the above embodiment, in the step of sucking and removing moisture in the gap g1 of the first filter medium layer 12 by the suction device 35, in the gap g1 of the surface layer portion on the second filter medium layer 13 side of the first filter medium layer 12, As shown in FIG. 4, some of the fibers 16 of the second fibers 16 of the second filter medium layer 13 were drawn. For this reason, while being able to improve the joint strength of the 1st filter medium layer 12 and the 2nd filter medium layer 13, the density of the fiber per unit volume of the surface layer part of the 1st filter medium layer 12 increases, and this surface layer part The amount of dust trapped in the air can be increased.

  (4) In the above embodiment, the filter element 11 is configured by the first filter medium layer 12 having a large thickness t1 and a small porosity and the second filter medium layer 13 having a small thickness t2 and a large porosity. Yes. For this reason, relatively large dust contained in the air filtered by the second filter medium layer 13 is captured, fine dust is captured by the first filter medium layer 12, and the filter element 11 as a whole effectively collects and captures dust. It can be carried out.

In addition, you may change the said embodiment as follows.
-Instead of the formation method of the 2nd filter medium layer 13 by the said meltblown apparatus 31, you may make it form the filter medium layer 13 by the electrospinning method. In this method, a high voltage is applied to the polymer solution to spray the solution on the upper surface of the first filter medium layer 12, and an infinite number of fine fibers are thinly laminated on the upper surface of the first filter medium layer 12 to form a nonwoven sheet. The second filter medium layer 13 is formed. The fiber diameter is set to 50 to 500 nm.

  The first filter medium layer 12 and the second filter medium layer 13 are sent to the suction device 35 after the band-shaped second filter medium layer 13 manufactured in advance is laminated on the surface of the wet first filter medium layer 12. Also good. Also in this case, a dedicated bonding process for bonding the first filter medium layer 12 and the second filter medium layer 13 and an adhesive therefor are not required, and the manufacturing process can be simplified and the filter element 11 can be simplified. The pressure loss of the fluid that permeates can be reduced.

The moisture of the first filter medium layer 12 may be sucked and removed by the suction device 35 simultaneously with the formation process of the second filter medium layer 13 by the melt blown device 31.
A wet second filter medium layer 13 made in the same manner as the first filter medium layer 12 is laminated on the upper surface of the wet first filter medium layer 12 so that moisture is removed from both layers 12 and 13 by suction. You may comprise.

The suction device 35 may be omitted, and the moisture in the wet first filter medium layer 12 may be removed by heating using a heating device. In the case of this embodiment, the same fiber as the second fiber 16 of the second filter medium layer 13 is not drawn into the gap g1 of the first filter medium layer 12, but as described above, the first filter medium layer 12 and A dedicated bonding step for bonding the second filter medium layer 13 and an adhesive for that purpose are not required, the manufacturing process can be simplified, and the pressure loss of the permeating fluid can be reduced. This embodiment corresponds to the present invention.

-Organic fibers of various plants such as mulberry leaves other than the pulp for producing the first filter medium layer 12 may be used, and resin fibers such as polypropylene and polyethylene may be used.
-The mercerized fiber may be used as the first fiber 14 of the first filter medium layer 12.

The present invention may be embodied in, for example, a filter element such as an air conditioner in addition to a filter element used for an automobile air filter.
(Technical thought)
The technical ideas other than the claims ascertained from the above-described embodiment will be described.

(1) before Symbol forming a second filter layer, the method for producing a filter element, characterized in that it is made by melt-blown method.
(2) Before Symbol forming a second filter layer, the method for producing a filter element, characterized in that it is carried out by electrospinning method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view showing an embodiment in which the present invention is embodied in a filter element used for an air filter of an automobile. Explanatory drawing of the manufacturing process of a 1st filter medium layer. Explanatory drawing of the manufacturing process of a 2nd filter medium layer. Explanatory drawing of the process of suction-removing a water | moisture content. Explanatory drawing of the adhesion process of a 1st filter medium layer and a 2nd filter medium layer. FIG. 3 is a schematic configuration diagram illustrating a filter element manufacturing apparatus.

Explanation of symbols

  g1, g2 ... Gap, 11 ... Filter element, 12 ... First filter medium layer, 13 ... Second filter medium layer, 14 ... First fiber, 15 ... Adhesive, 16 ... Second fiber, 16a ... Contact part, 35 ... Suction apparatus.

Claims (1)

A first step of forming a first filter medium layer by making a slurry in which a first fiber is dispersed in a liquid;
A second step of forming a second filter medium layer comprising second fibers on the upper surface of the first filter medium layer;
A third step of removing moisture contained in at least the first filter medium layer among the first filter medium layer and the second filter medium layer in a wet state simultaneously with the second process or after the second process;
After the third step, the fourth step of impregnating both the filter media layers with an adhesive and bonding the contact portion between the first fibers and the contact portion between the first fiber and the second fiber with an adhesive;
After said fourth step, seen including a fifth step of drying the first filter layer and second filter layer,
The method for producing a filter element is characterized in that the step of removing moisture is performed by heating and drying the first filter medium layer .

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