Technical Field The present invention relates to a method of manufacturing an air -cleaning filter fo r a vehicle, in which a filter media made of non-woven fabrics having a good dust holding capacity is pleated at regular intervals of a desired width, the spacing between the peaks of the pleated filter media is fixed and stabilized by using an edge banding and a resin at both edges of the pleated filter media, and a frame is formed by foaming polyurethane capable of significantly improving the productivity of the air -cleaning filter, and to an air -cleaning filter manufactured by the method.

Background Art Conventional techniques relevant to the present invention will be described below. The car air -cleaning filter element employs mainly a non -woven filter media and a paper filter media. In case of the non -woven fabric filter media and the paper filter media, 0.38m2 and 0.7m2 are used respective, and the case of paper filter media consumes 1.8 times more. In the terms of dust collecting capacity, however, the non -woven fabric filter media has 259g/element, and the paper filter media has 70g/element. The non-woven fabric filter media has a 3.6 times higher duct -collecting capacity. That is, this means that the non-woven fabric filter media has a 3.6 times longer life time than that of the paper filter media. The amount of dust to be collected depends on the structure of the filter media, and the non-woven fabric filter media is more advantageous, as compared with the paper filter media. Conventionally, in the case where a paper filter media is pleated and molded using a polyurethane frame to thereby fabricate a paper air -cleaning filter, its productivity is approximately 700-800 filters per hour. When an air -cleaning filter using a non -woven fabric filter media is formed through an insert injection frame (using a thermoplastic material), the productivity thereof is about 100-110 filers per hour. The case of paper filter media has a higher productivity than that of the non-woven fabric filter media. That is, in the case where the non -woven fabric filter media having a higher dust collecting capacity is use s, it requires much time and cost to forming the insert injection frame, and thus its productivity is low and its production cost is high. In case of the paper filter media, the productivity is high because the frame is molded using urethane, but its dust collecting capacity is very low due to the characteristic of the paper filter. These problems can be solved by introducing an insert injection frame. That is, since the non -woven fabric filter media made of synthetic fiber series materials (VP, PE, PP) is thicker and more resilient than the paper filter media made of a pulp material, the insert injection frame can be used in order to pleat the non -woven fabric filter media at regular intervals and maintain a constant spacing between the peaks of the pleated filter media.

Disclosure of Invention The present invention has been made in order to solve the above problems occurring in the prior art, and it is an object of the invention to provide a method of manufacturing an air cleaning filter for automobiles having a good dust collecting capacity and an improved productivity, in which a filter media made of non-woven fabrics having a good dust collecting capacity is used, a frame is molded using polyurethane series materials inexpensive and capable of signifi cantly improving the productivity, the filter media made of non -woven fabrics is pleated uniformly at desired intervals, a non -woven fabric or a fabrics is coated with a hot -melt and adhered and cured to both edges (end portion) of the pleated filter media , or the both edges thereof are coated with the hot -melt and cured, thereby maintaining the spacing between the peaks of the pleated filter media and thus stabilizing the pleated filter media, and then the frame is formed using polyurethane series material s relatively inexpensive and capable of using a simple process. Another object of the invention is to provide an air -cleaning filter manufactured by the method of the invention. In order to accomplish the above object, according to one aspect of the inven tion, there is provided a method of manufacturing an air -cleaning filter for a vehicle. In the method of the invention, a filter media made of non -woven fabrics having a good dust holding capacity is pleated at regular intervals of a desired width, the sp acing between the peaks of the pleated filter media is fixed and stabilized by using an edge banding and a resin at both edges of the pleated filter media, and a frame is formed by foaming polyurethane capable of significantly improving the productivity of the air - cleaning filter. According to another aspect of the invention, an air-cleaning filter manufactured by the method is provided.

Brief Description of Drawings Further objects and advantages of the invention can be more fully understood from the fo llowing detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 illustrates a knife -pleating process according to the invention; FIG. 2 illustrates an edge-banding process according to the invention; FIG. 3 illustrates a rotary-pleating process according to the invention,- and FIG. 4 illustrates an emboss-treating process using a rotary-banding roll according to the invention.

Best Mode for Carrying Out the Invention The preferred embodiments of the present invention will be hereafter described in detail with reference to the accompanying drawings. The use and function of an air -cleaning filter manufactured according to the invention will be described below. In case of automobiles using an internal combustion engine, ext ernal air and fuel are appropriately mixed and injected into the inside of the cylinder. The injected air is mixed with the fuel. The mixing of the air with the fuel affects significantly the performance of the engine. In particular, when impurities foreign particles contained in the air flown from outside are introduced inside of the engine without filtration, the engine may suffer from critical damages. To solve this problem, the air-cleaning filter manufactured according to the invention is used for filtering and cleaning the air in -flowing into the engine by installing it in that portion of the engine that the external air is introduced through. The structure of this air cleaning filter for automobiles is composed of a filter media and a frame. Actu al collection of dust takes places in the filter media. The frame functions to pleat the filter media in certain intervals and maintain the bent form of filter media so that the performance of the filter is retained for a long time and leakage of the airfl ow from outside is prevented. As an approach in order to solve the above problems in the art, the present invention employs a non -woven fabric of synthetic fiber (VR, PE, PP) , which has an excellent dust collection capacity. The frame is made of polyureth ane series materials. The invention has proposed a process for forming a polyurethane frame in a simple and inexpensive way and in a short time. Also, the present invention has provided a method of manufacturing an air-cleaning filter for automobiles in an inexpensive and high - productive way, and an air -cleaning filter manufactured according to this method. The air -cleaning filter of the invention is composed of a non -woven fabric and a polyurethane frame and has an excellent capability of duct collecting. The constitutional means according to the invention will be specifically described below. The process for manufacturing an air-cleaning filter using a filter media made of non -woven fabrics is generally comprised of a pleating process and a process for f abrication a frame. In the pleating process, a knife pleating machine and a rotary pleating machine is used for pleating non-woven fabrics or papers. The knife -pleating machine is composed of an unwinder, a width cutter, a pre -heater, a pleating knife, and a main heater or an oven. The pleating process using a knife -pleating machine is composed of steps of cutting into a desired width a filter media made of non -woven fabrics, passing them through a pre -heater to smooth the filter media, then pleating them u sing a knife, and stabilizing the pleated filter media using a main heater or an oven. In order for the above pleated filter media to be adopted as a car air -cleaning filter media, a process for manufacturing a polyurethane frame is carried out. In the fra ming process using polyurethane, a frame is manufactured by banding both edges of the filter media, which is pleated by means of the knife-pleating machine. As the edge member to be attached to both edges, non -woven fabrics, papers or plate -like things are used. The edge member is cut such that its width is l~3mm larger than the peak height of the pleated filter media. The cut edge is wound around a roll and fixed in a position to have easy access to the both edges of the pleated filter media. The pleated filter media is fit into a jig in order to maintain the constant intervals of peaks. After that, the edge member is coated with resin and adhered to the edge of the pleated filter media for banding. Thereafter, as illustrated in FIG. 2, a hot - melt resin, which is melted in a hot -melt applicator, is sprayed through a hot -melt nozzle and coated evenly in the edge member. The edge member coated with the hot -melt resin is adhered to the both ends of the filter media fitted into the jig, before the coated resin is cured. The edge member is uniformly stuck to the both ends of the filter media by pressing using a small roll or other devices capable of exerting a pressure. Upon completion of sticking the edge member, the filter media with the edge member stuck t hereto is cooled in the air for a certain period of time. When the hot -melt resin is cooled and cured, the adherence of edge member is stabilized, and thus the edge banding process is finished. Here, in the case where the width of the filter media is abov e 50mm, a rib is inserted in order for the filter media not to sag by the force of air, or the center of the filter media is coated with the hot -melt resin using a nozzle, thereby preventing the occurrence of dead space in the filter media. As a method of inserting the rib, plastic materials, hard board papers, aluminum or iron (SUS) , or the like are made in a different shape and size, depending on the shape of the peak (height, interval) , and inserted into the center of the pleated filter media and then f ixed by foaming polyurethane. The dead space means a space, which fails to collect dust. For example, the pleated filter media sags or leans sideways by means of the air pressure when the air passes through the filter, and this affects neighboring pleated filter medium to thereby make them sag or lean by a domino theory. Therefore, the folded or contacted portions of the filter media, i.e., the dead space, fail to collect dust. In this way, if a dead space is generated in the filter media, its dust collect ing capacity is decreased and loss of pressure is increased, so that the filter performance is significantly deteriorated. After the adhering of the edge banding of the pleated filter media is completed, an urethane foaming process is carried out, which is a final step of the process for manufacturing an air -cleaning filter frame. If the edge banding process is finished, the filter media pleated in regular intervals and fixed is produced. A polyurethane frame is formed in the pleated filter media using a die mould, in order to prevent the deformation of the pleated filter media, and air leak through a gap generated in the edge. In the manufacturing of the frame, a die mould is required for foaming and molding liquid polyurethane. The molding die is composed of an upper and lower part and structured so as to minimize deformation of the pleated filter media during the molding process in order to provide a good filter performance. In the manufacturing process, polyurethane is poured using a urethane chute device through the groove of the lower die having a desired shape. Then, the pleated filter media is put into the die poured with the polyurethane in such a manner that the edge - banding portion with the hot -melt resin is oriented downwardly. Thereafter, the upper die is placed, in order to maximally prevent deformation of the pleated filter media during the foaming process. After the urethane foaming is completed and the upper and lower die is removed, an air -cleaning filter is produced for automobiles. Altho ugh the foaming of the polyurethane may be carried out at room temperature, it is advantageous to use an oven in order to promote the foaming rate. It is appropriate that the temperature of the oven is maintained in the range of 50~100 0C. In the process f or manufacturing the frame, polyurethane or an elastic material is employed since using these materials does not require any separate packing material for preventing the air -leakage, so that the • manufacturing cost can be reduced and the production speed can be increased. The gap between the peaks of the pleated filter media is within a range between 2 mm and 5mm. Nest, the rotary pleating mode will be explained. The rotary pleating machine is composed of a pre -heater, a pleating roll, and a main heater. The process promotes pleating workability by softening the filter media in the pre -heater. The pleating roll is composed of an upper and lower roll. The upper and lower roll has a raised portion and a depressed portion alternately engraved and having a d esired pleating height. While the filter media passes, a negative imprint and a positive imprint having a determined peak height are generated. While passing the main heater, the speed is lowered, and thus due to the lowered speed, a pleating is generate d by means of the negative and positive imprints formed above. The heat of the main heat stabilizes the pleated form . An advantage of the rotary pleating is its higher speed, and a disadvantage thereof is its difficulty in pleating a wider width. As illustrated in FIG. 3, the rotary pleating machine is constituted of an unwinder, a pre -heater, a pleating roll, and a hot-melt applicator. The rotary pleating process is composed of step of a) passing a filter media through the pre -heater to soften it, b) fo rtning a pattern in the filter media having an emboss and a desired peak height by passing the filter media through the pleating roll engraved with a pleating line and various patterns, and c) pleating the filter media along the imprints pressed while passing the pleating roll. Both edges of the pleated filter media are coated with a hot -melt resin, which is made by melting thermoplastic resin such as e thylene-vinyl acetate (EVA) , polyester, Polyamide. The both edges of the filter media are completely adhered by the coated hot -melt resin, and thus a pleating of the filter media is finished, without air-leakage through the both edges thereof. The pleating roll is composed of an upper and lower roll . Since the pleated width is relatively narrow within 4mm, the resin coated on the edge of the pleated filter media enables adhering of the edges of the pleated filer media while maintaining the constant gap between the peaks thereof. Also, the leakage of unfiltered air is prevented by sticking the both edges of the filter media. The filter media finished with the above rotary pleating machine is provided with a frame, which is manufactured using polyurethane and a die mould. The method of manufacturing a frame is the same as that used in the knife pleating. The operational effect of the frame manufactured the same method is also identical .

[Example 1] A filter media made of non -woven fabrics is used as the filter media. The non -woven fabric filter media has a weight of 50 to 500g/m2, a thickness of 0.5 to 7.0mm, and a permeability of 20 to 300cc/cm 2/sec. Although the non -woven fabric filer media may be pleated by a rotary pleating mode or a knife -pleating mode, the knife -pleating mode is employed in the example 1. In the pleating process, the selected non -woven filter media is hung on the unwinder, and the tension is lowered such that the filter media is slowly and smoothly unwound and then cut in a desired constant width using a cutter. The cutting of the filter media into a desired width is carried out in such a manner that an pre -installed ruler or other measuring devices is fixed at the position where the cuter is placed, and then the cutting of the filter media is carried out while passing it . The shape of the cutter is preferred to be circular as shown in FIG. 1. The cutting is partly carried out in the form of a dotted line, in stead of complete cutting, so that each width is prevented from being disturbed during the pleating process. The filter media finished with the cutting process passes the pre heater and then is pleated, using a knife already -installed conforming to the peak height to be pleated. The filter media finished with the pleating process passes the main heater, in which a heat treatment is performed so as not to disturb the pleating, thereby completing the pleating. Next, in order for the pleated filter media to be applied as an air -cleaning filter for a car, a frame is manufactured. In the framing process using polyurethane, both edges of the filter media pleated by the knife-pleating machine are banded with an edge member, and then the frame is manufactured. The edge member to be adhered to the both edges of the filter media may employ non -woven fabrics, fabrics, papers or other plate -like materials. The edge member is cut so as to have a wi dth of l~3mm larger than the peak height of the pleated filter media and wound around a roll . As illustrated in FIG. 2, the rolled edge member is fixed in the position to have easy access to both edges of the pleated filter media. The pleated filter media is fixed into a jig in order to maintain the constant peak spacing thereof. Then, the edge member is coated with resin and banded to the edge of the filter media. As depicted in FIG. 2, the hot -melt resin melted in the hot-melt applicator is sprayed thro ugh a nozzle and evenly- coated on the edge member. The edge member coated with the hot melt resin is adhered to the both edges of the filter media fitted into the jig, before the resin is cured. The edge member is evenly adhered to the both edges of the fi lter media by pressing it using a small roll or other devices capable of exerting a pressure. The filter finished with the adhering process is cooled in the air for a certain period of time, and then the resin is cooled and cured, so that the edge banding process is finished by stabilizing the adhering by the edge member. Here, in the case where the width of the filter media is above 50mm, a rib is inserted in order for the filter media not to sag by the force of air, or the center of the filter media is coated with the hot -melt resin using a nozzle, thereby preventing the occurrence of a dead space in the filter media. As a method of inserting the rib, plastic materials, hard board papers, aluminum or iron (SUS) , or the like are made in a different shape a nd size, depending on the shape of the peak (height, interval) , and inserted into the center of the pleated filter media and then fixed by foaming polyurethane. The dead space means a space, which fails to collect dust. After the edge banding process of t he pleated filter media is completed, a urethane foaming process is carried out, which is a final step of the process for manufacturing an air -cleaning filter frame. If the edge banding process is finished, the filter media pleated in regular intervals an d fixed is produced. A polyurethane frame is formed in the pleated filter media using a die mould, in order to prevent the deformation of the pleated filter media, and air leak through a gap generated in the edge. In the manufacturing of the frame, a die mould is required for foaming and molding liquid polyurethane. The molding die is composed of an upper and lower part and structured so as to minimize deformation of the pleated filter media during the molding process in order to provide a good filter perf ormance. In the manufacturing process, polyurethane is poured using a urethane chute device through the groove of the lower die having a desired shape. Then, the pleated filter media is put into the die poured with the polyurethane in such a manner that the edge- banding portion with the hot -melt resin is oriented downwardly. Thereafter, the upper die is placed, in order to maximally prevent deformation of the pleated filter media during the foaming process. After the urethane foaming is completed and the upper and lower die is removed, an air -cleaning filter is produced for automobiles. Although the foaming of the polyurethane may be carried out at room temperature, it is advantageous to use an oven in order to promote the foaming rate. It is appropriate that the temperature of the oven is maintained in the range of 50-100 °C. In the process for manufacturing the frame, polyurethane or an elastic material is employed since using these materials does not require any separate packing material for prevent! ng the air -leakage, so that the manufacturing cost can be reduced and the production speed can be increased. The gap between the peaks of the pleated filter media is within a range between 2 mm and 5mm.

[Example 2] Example 2 relates to a method of manufa cturing an air - cleaning filter using a rotary pleating machine, which uses a filter media made of non -woven fabrics having a good dust collecting capacity and a polyurethane frame capable of significantly improving the productivity, and to a polyurethane frame air -cleaning filter manufactured according to the above method. In this method, the filter media made of non -woven fabrics is cut into a desired width to be used. Dissimilar to the knife -pleating process in the example 1, the pleating process does n ot carry out cutting. In pleating, the pleating roll is most important. The pleating roll is composed of an upper and lower roll . The pleating roll has a positively engraved portion (a raised portion) and a negatively engraved portion (depressed portion ) . These engraved portions have two functions. First, the roll has peaks engraved in certain regular intervals in order to pleat with a peak height to be pleated, and the engraved portion is made in one of the rolls. The engraved portion is made in a st raight-line form over the roll. In the other roll, a depressed portion may be made, or none. One the roll may have a negatively engraved portion and the other may have a positively engraved portion. In this way, the engraved portions are repeatedly form ed along the circumferential surface of the roll at regular intervals. When a filter media having a constant width is passed between the peaks of above -engraved roll, an emboss engraved with a raised portion and a depressed portion is formed in the surfac e of the filter media. In order to form the pleating or bending in easier manner, at the center portion between the embosses, one of the roll is positively engraved and the other roll is engraved negatively, so that the spacing between the peaks is maintained constantly, after the pleating of the filter media is completed by the pleating roll. As the filter media, similar to the example 1, a filter media made of non -woven fabrics is used. The filter media is transferred from the unwinder and softened through the pre -heater, and then passes the pleating roll. At this time, a pattern presenting a pleating width is formed in the filter media according to the engraved form of the roll . Also, an emboss for maintaining the spacing between the peaks is formed in the filter media. A hot -melt resin is coated in both edges of the filter media. The constituent of the coated hot melt includes e thylene-vinyl acetate (EVA), polyester, Polyamide, and the like. The advancing speed of the filter media coated with the hot-melt resin is lowered to pleat the filter media at regular intervals according to the pleating pattern. The hot melt resin coated on the both edges of the pleated filter media is stuck and cured, so that air -leakage through the both edges of the pleat ed filter media can be prevented, and the pleating pattern formed at the regular interval is maintained. The width between the peaks of the pleated filter media is relatively narrow within 4mm, and thus the air -leakage through the edges of the pleated fil ter media can be prevented by means of the adhering of the resin coated on the both edges of the pleated filter media. In the case where the width of the pleated filter media is larger than 50mm, a hot -melt resin is coated in the center of the pleated fil ter media in order to fix the spacing between the peaks of the pleated filter media, thereby preventing generation of dead space, which may be occurred when the air -cleaning filter is used. As another method of preventing the dead space, similar to the ex ample 1, a rib is inserted and fixed by molding with a polyurethane frame. The manufacturing process of the polyurethane frame is carried out in the same manner as in the example 1. Industrial Applicability As described above, according to the invention, a filter media made of non -woven fabrics having a good dust collecting capacity is used, and a frame is molded using polyurethane series materials capable of significantly improving the productivity, along with a reduced manufacturing cost. That is, the filter media made of non -woven fabrics is pleated uniformly at desired intervals. A non -woven fabric or a fabrics is coated with a hot -melt and adhered and cured to both edges (end portion) of the pleated filter media, or the both edges thereof are coated with the hot -melt and cured, thereby maintaining the spacing between the peaks of the pleated filter media and thus stabilizing the pleated filter media. Then the frame is formed using polyurethane series materials relatively inexpensive and capable of u sing a simple process. Therefore, a good dust collecting capacity can be achieved, and the productivity can be significantly improved, together with a reduced manufacturing cost. While the present invention has been described with reference to the particu lar illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.