KR20070109848A - A/c pre-filter with micro-pores - Google Patents

Abstract

An air conditioning pre-filter is provided to remove effectively fine dust, by coating an outer surface of a non-woven fabric layer with a foam layer forming a three-dimensional net structure having fine pores, simplify a manufacturing process, and reduce a manufacturing cost. An air conditioning pre-filter comprises a non-woven fabric layer contacted with the air and a foam layer formed on an outer surface of the non-woven fabric layer. The non-woven fabric layer has a density distribution of which the lowest density is 50 g/m^2x1mmT, and the highest density is 200 g/m^2x1mmT. The density is gradually increased from a contact point between the non-woven fabric layer and the air in an exhausting direction of the air. The foam layer forms a three-dimensional net structure having pores of 10-15 um.

Description

A / C pre-filter with micro-pores

1 is a schematic diagram (a) showing a slim structure of a conventional medium filter and a schematic diagram (b) showing a fine dust filtration method of a medium filter, a cross-sectional photograph (c) showing a nonwoven fabric layer of an air conditioning prefilter of the present invention, and the present invention. The photograph (d) which shows the stepwise filtration system of the air-conditioning prefilter nonwoven fabric layer of this invention is shown.

Figure 2 is a schematic diagram showing the cross-sectional structure of the air conditioning prefilter having a three-dimensional micropores according to the present invention.

Figure 3 is a schematic diagram showing the cross-sectional structure and the filtration method of the air conditioning prefilter (a) and the existing dust collecting prefilter (b) of the present invention.

4 is a schematic view showing a manufacturing process of an air conditioning prefilter having three-dimensional micropores according to the present invention.

Figure 5 is a photograph of the (a) foam coating surface, (b) side cross-section and (c) uncoated nonwoven surface of the air conditioning prefilter prepared in Example 2 of the present invention observed with an electron microscope.

FIG. 6 is a graph showing changes in the fine dust removal efficiency of the air conditioning prefilter (a) prepared by Example 2 of the present invention, and the air conditioning prefilter before the resin coating of Comparative Example 1.

<Explanation of symbols for main parts of drawing>

10: bubble generator 11: foam coating machine

12: foam supply nozzle 13: resin foam

14: media 15: roller

16: stator 17: rotor

18: emulsion solution supply pipe 19: air pressure supply pipe

20: crosslinking agent supply pipe

The present invention relates to a pre-filter for air conditioning having three-dimensional micropores, and more particularly, a foam-like resin having fine pores on the outer surface of a nonwoven fabric layer having a large density of voids and having a gradually increasing density distribution. The present invention relates to a pre-filter for air conditioning in which a foam layer formed by coating, gelling and drying is laminated.

In general, in the steel industry, cement industry, industrial sites that use powder or produce powder-type products, polluted air containing a large amount of dust is discharged in many processes. Because of the potential for serious air pollution, all companies are required to purify and release polluted air into the atmosphere.

Usually, there are two types of filters as air purifying means, a dust collecting filter and an air conditioning filter, and their characteristics can be shown in Table 1 below.

division Dust collection filter Air Conditioning Filter Usage Removal of high concentration macro dust [process dust] Low concentration fine dust removal [air dust] Critical differential pressure Short time of arrival Starts after exhausting when the critical differential pressure is reached Replace filter when arrival time reaches critical differential pressure Filtration method Surface filtration In-Depth Filtration Filtration rate Slow (average 1 m / min) Fast (2.5 m / min average) Media Varies according to dust collection conditions and type of dust Multi-level media setting according to indoor air quality

That is, as shown in Table 1, the filter for dust collection is mainly applied to filter the high concentration of large dust generated during the manufacturing process, it is characterized by a short time to reach the critical pressure difference and a slow filtration rate.

On the other hand, the air-conditioning filter is applied to filter the low concentration fine dust by atmospheric dust, it is characterized by a long time to reach the critical differential pressure and fast filtration speed. The air conditioning filter is set to filter media in multiple stages such as PRE, MEDIUM, HEPA, ULPA, etc. according to the required indoor air quality (IAQ).

Among the filter media formed in the multi-stage, the most important performance of the pre filter is to have excellent air permeability and fine and uniform air gaps, so that high air permeability does not pass through the air well.

The best performance of this is nonwovens, and most pre filters are made of nonwovens. In addition, the filter is required properties such as heat resistance, flame resistance, moisture permeability, water resistance, water repellency.

However, with the development of the industry, more and more fine dusts are generated, and in order to improve environmental protection and working environment, there is a problem of efficiently collecting and removing finer dusts.

Medium filter among the filter media formed in the multi-stage is a filter showing a moderate filtration performance in the structure of heat, ventilating and air conditioning (HVAC) system [PRE-MEDIUM-HEPA filter], a low concentration of fine dust (0.3 ~ 3 ㎛ It is used to remove [air dust], and it shows the characteristic of air-conditioning filter to replace the filter when the critical differential pressure is long. The dust filtration efficiency of the medium filter is at least 75% for dust in the range of 0.3 to 1 μm and at least 90% for dust in the range of 1 to 3 μm.

However, the existing air-conditioning filter has a high differential pressure of the filter, the higher the dust filtration efficiency, the higher the dust loading rate of the surface due to the thinner the filter medium, the more space to be secured by the multi-stage HAVC system, or the need for high wind power This remains. In addition, since the use of a low grade pre-filter, expensive medium filter 1 to 3 ㎛ dust is exposed to more than 50%, the filter life is shortened.

Therefore, the development of a filter capable of operating at a low differential pressure while maintaining high filtration efficiency of dust, having a low surface dust load rate, requiring a large space, and operating at a low air flow is required.

On the other hand, in the conventional case by coating an acrylic resin or urethane resin solution using an organic solvent on a paper treated with silicon, irregularities, etc., laminating it together with a nonwoven fabric and calendering to attach the film on the surface of the nonwoven fabric Filters have been manufactured.

However, the above method has a problem that the pore size is formed very large to effectively remove the fine dust, and the working environment is poor due to the use of organic solvents and poses a risk of fire.

In addition, after preparing the foam by mixing the acrylic resin solution and air, a method of padding the foam on the nonwoven fabric using a pad or a knife has been applied a lot, but such a method by the physical force of the knife or the pad itself Since the foam structure is broken, there is a disadvantage in that it does not form a three-dimensional foam structure on the surface of the nonwoven fabric and merely gives strength between the nonwoven fibers.

In addition, recently, a method of injecting air into an emulsion solution to generate a resin foam and coating it on the surface of the nonwoven fabric with a foam coating machine has been introduced, but this method forms finer dust by forming bubbles having an average diameter of 25 μm or more. There is a disadvantage that can not be filtered.

Moreover, the filters to date are mainly focused on the development of the dust collecting filter, and the development of the air conditioning filter is not very active.

On the other hand, high-efficiency filters are now preferred due to the recognition of the harmfulness of fine dust and the strengthening of atmospheric environment standards. Therefore, the pre-filter used in general is 7 or 8 in the ASHRAE standard MERV (MERVE) standard, but in advanced countries it is possible to collect fine dust with the pre filter. The trend is to switch to MERV 11.

The American Society of Cold Air Conditioners (ASHRAE) Standard 52.2 test chart is briefly presented in Table 2 below.

ASHRAE 52.2 apply MERV Total mean efficiency (by dust size range),% Range 1 0.3 ~ 1.0㎛ Range 2 1.0 ~ 3.0㎛ Range 3 3.0 ~ 10.0㎛ 2 Groups [Low Efficiency Prefilter]: Commercial Building, High-grade Housing, Industrial Workshop, Painting Booth Inlet Air, etc. 5 - - 20 to 35% Dust from 3.0 to 10.0 µm: mold, spores, hairspray, textile protector, cement dust, pudding powder, powdered milk 6 - - 35-50% 7 - - 50 to 70% 8 - - > 70% 3 Groups [High Efficiency Prefilters]: Best Housing, Commercial Buildings, Hospital Offices, Laboratories, etc. 9 - <50% > 85% 1.0 ~ 3.0㎛ dust: rayonella, humidifier dust, lead dust, flour, carbon dust, automobile exhaust, spray liquid droplets, welding gas 10 - 50 to 65% > 85% 11 - 65 to 80% > 85% 12 - > 80% > 90% Group 4 [medium filter]: hospital patient nursing, general surgery, smoking room, top commercial building, etc. 13 <75% > 90% > 90% Dust from 0.3 to 1.0 μm: all bacteria, most tobacco smoke, small water sneezes, insecticide dust, toner, most cosmetic powder, most pigments 14 75 to 85% > 90% > 90% 15 85 to 95% > 90% > 90% 16 > 95% > 95% > 95% Group 5 [HEPA / ULPA filter]: clean room, radioactive materials, pharmaceuticals, carcinogens, orthopedic surgery, etc. 17 ≥99.97% - - Dust ≤0.3 μm: unaggregated virus, carbon dust, sea salt, all soot, radon products 18 ≥99.99% - - 19 ≥99.999% - - 20 ≥99.9999% - - Minimum Efficiency Reporting Value (MERV)

However, commercially available high efficiency pre filters (PRE) have been recognized as a problem that the use of high efficiency filters in the enterprise or at home because of high price and complicated manufacturing process.

Accordingly, the inventors of the present invention have made efforts to develop a new air-conditioning filter having a characteristic that meets the above requirements. As a result, the density gradually increases in the direction of air flow [nonwoven fabric layer → foam layer] from the outside air contact surface. A non-woven fabric with bulky properties showing the distribution and a large amount of voids therein is coated with a foam of resin with micropores, followed by gelation and drying, suitable for deep filtration and comparable to medium filters. The present invention has been found to have a high efficiency capable of effectively removing fine dust in the range of 1 to 3 μm and to produce an air conditioning prefilter exhibiting low differential pressure characteristics.

Accordingly, an object of the present invention is to provide a pre-filter for air conditioning having three-dimensional micropores that are very inexpensive, high in efficiency, and on the other hand, can actively cope with the gradually increasing atmospheric environmental standards.

As one embodiment for achieving the above object the air conditioning prefilter of the present invention,

It is formed on one side in contact with the incoming outside air, and gradually increases in density along the direction in which the outside air is discharged from the contact surface into which the outside air flows, with a minimum density of 50 g / m 2 × 1 mmT and a maximum density of 200 g / m 2. A bulky nonwoven layer having a density gradient of up to 1 mmT; Characterized in that the air-conditioning pre-filter (PRE-filter) having a three-dimensional micropores formed on the outer surface of the non-woven fabric layer and the foam layer in which the pores in the range of an average of 10 to 15 ㎛ form a three-dimensional network structure is laminated. .

Hereinafter, the present invention will be described in detail.

The present invention relates to a filter for air-conditioning in which a foam layer formed by applying a gel-like resin having a fine pore on the outer surface of a nonwoven fabric layer having a large density of voids and having a density gradient is formed by gelation and drying. As the included outside air passes through the nonwoven fabric layer and the foam layer which constitute the air conditioning prefilter sequentially, the fine dust can be removed quickly and effectively by the deep filtration method, so that the fine dust removal efficiency is high, economically inexpensive, and gradually strengthened. The present invention provides a method for manufacturing an air-conditioning prefilter having three-dimensional micropores that can actively cope with an existing air environment standard by a simple and economic process.

Hereinafter, the air conditioning prefilter of this invention is demonstrated concretely.

First, the air-conditioning filter of the present invention includes a non-woven fabric layer formed on one side in contact with the outside air containing fine dust.

The non-woven fabric layer, which is the basic filter material, is formed on one side contacting the introduced external air, and exhibits a bulky characteristic of gradually increasing density along the direction in which the external air is discharged from the contact surface on which the external air is introduced. At this time, the non-woven fabric layer has a minimum density of 50 g / m 2 x 1 mmT, preferably 50 g / m 2 x 1 mmT or more, and a density gradient of 200 g / m 2 x 1 mmT or less, preferably 200 g / m 2 x 1 mmT or less. It is configured to gradually increase the density while indicating.

The total thickness of the nonwoven fabric layer is preferably in the range of 1.5 to 5 mm, preferably in the range of 2 to 3 mm, and when the total thickness of the nonwoven layer is less than the above range, the dust collection efficiency is lowered and exceeds the above range. If large, the filtration performance tends to be lowered because a large amount of filtration cannot be added to the structure used by bending.

It is good to comprise the said nonwoven fabric layer so that the thickness of the part which shows the lowest density may be 25 to 50% of the whole thickness, and it is good to comprise so that the thickness of the part which shows the maximum density may be 10 to 50% of the total thickness. The remaining portion should consist of a range between the lowest and the highest density.

In the past, a low density high density filter medium was used to filter 1 to 3 μm of dust, but in the present invention, a resin foam coating was applied to a nonwoven fabric layer having the above characteristics to improve air permeability and filtration performance.

 This structure exhibits staged filtration performance from the first large dust to small dust (more than 10 μm → 3 to 10 μm → 1 to 3 μm). Among these, the maximum density layer coexists with the fiber density layer (Pore size: 40 to 80 µm) and the resin foam layer (Pore size: 10 to 15 µm), thereby obtaining a function of filtering to fine dust of 1 to 3 µm.

At this time, when the thickness of the portion having the lowest density is smaller than the above range, the dust holding efficiency (DHC) tends to be low, and when the thickness of the portion having the maximum density is larger than the above range, the system differential pressure (ΔP) is increased. ) Increases efficiency, but shortens the filter life.

Secondary high density filter media (M, B: melt brown, Membrane) because non-woven fabrics show non-uniform pore sizes (40 to 80 ㎛) due to differences in fiber thickness and density even when forming density gradients showing different densities. Lamination is done using). However, the boundary surface of these two layers is formed with a sharp pore layer gap, the contact surface falls due to the differential pressure rise and the external air volume. Compared with the uniform distribution of density, the present invention can be said to have a characteristic technical configuration in forming a density gradient showing a different density depending on the part of the filter. That is, the air conditioning prefilter of the present invention is composed of a nonwoven fabric layer having a multi-layer structure according to the density gradient, thereby preventing a sudden rise in the differential pressure.

As such, it is formed to have a density gradient that gradually increases along the flow direction of the outside air, thereby imparting bulky characteristics as shown in FIG. 1 (c), and as shown in FIG. In the nonwoven fabric layer, the larger diameter is filtered and the smaller diameter is filtered as the density is increased. Therefore, since the dust is filtered step by step inside the filter medium, the increase in the differential pressure is relatively higher than that of the high dust collection amount. As a result, it is possible to obtain the effect of extending the life of the filter.

The conventional medium filter exhibiting similar filtration efficiency as the prefilter of the present invention is composed of a slim nonwoven fabric having a thickness of about 1 mm as shown in FIG. 1 (a), and the surface as shown in FIG. 1 (b). Since the dust is concentrated intensively, the amount of dust collected is very low, and the problem of shortening the life of the filter due to the rapid increase in the differential pressure is pointed out.

For reference, nonwoven fabrics generally used in the art exhibit uniform density, for example, a uniform density in the range of about 300 to 350 g / m 3 in a small area of 0.8 to 1.5 mm in thickness.

Fibers constituting the nonwoven fabric may use a variety of fibers applied to the filter is not particularly limited in its kind, but preferably low melting fiber in consideration of the bending (Pleatable), and foam coating properties, It is preferable to use low denia polyethylene terephthalate (PET) fibers.

Unlike the nonwoven fabric used in the existing dust collecting filter and the like, the air conditioning prefilter of the present invention is characterized by using a nonwoven fabric having a multi-layer structure that is given a gradually increasing density gradient. The advantages of high air permeability and high dust collection efficiency are obtained.

In the air conditioning prefilter of the present invention using the nonwoven fabric provided with the density characteristic as described above, as shown in FIG. 3, when external air containing fine dust passes through the nonwoven fabric layer, fine dust is collected in the voids formed in the nonwoven fabric layer. It can be expected that the effect of removing the dust to a high degree of 3 ㎛ or more by the voids,

That is, the conventional dust collecting filter adopts the principle of removing dust by surface filtration as shown in FIG. 3 (b), and unlike the case where dust is filtered by the foam layer, the air conditioning prefilter of the present invention. Since the dust is removed by the deep filtration method as shown in Fig. 3 (a), the dust of 3 μm or more is sequentially stacked on the deep layer of the nonwoven layer configured to increase in density depending on the size, and less than 1 to 3 μm In the case of fine dust having a diameter in the range it is filtered through the foam layer.

Therefore, the dust filter is removed by a completely different filtration method than the dust filter, which is effective to remove the high concentration of dust, and when the critical differential pressure is reached, the air-conditioning filter unlike the dust filter used by dedusting the filter. Replace the filter.

Next, the air conditioning prefilter of the present invention includes a foam layer.

The foam layer is formed on the outer surface of the nonwoven fabric layer and is configured to have pores in the range of 10 to 15 μm on average, and is laminated on the nonwoven fabric layer while having a three-dimensional network structure.

The foam layer is formed by stirring the resin emulsion to form a foam and then applying it to a low density nonwoven fabric, and exhibiting a double layer structure consisting of an interface including a part of the nonwoven layer and pure resin foam.

That is, since the foamed resin is naturally introduced into the low-density nonwoven fabric in which many voids are formed, the gap between the fibers constituting the nonwoven fabric is filled with the foam of the resin at the interface between the nonwoven fabric layer and the foam layer. At this time, the foam of the resin to be filled into the nonwoven fabric is preferably adjusted so that the thickness is in the range of 0.2 to 0.5mm, preferably 0.4 to 0.5mm. If the foam thickness of the resin introduced between the nonwoven fibers is larger than the above range, the layer of the network structure is high, so it is preferable to control the air permeability.

On the other hand, the foam layer purely made of resin is preferably adjusted in the range of 0.1 to 0.3 mm, preferably in the range of 0.2 mm.

That is, the entire foam layer constituting the air conditioning filter of the present invention, including the foam thickness of the resin introduced between the nonwoven fibers described above, is preferably adjusted in the range of 0.5 to 1 mm, preferably in the range of 0.7 to 0.8 mm. . At this time, if the thickness of the foam layer is less than the above range can not maintain a uniform pore size, if the thickness is over the above range may tend to fall short of the required air permeability.

The nonwoven fabric layer constituting the air conditioning prefilter of the present invention is formed on one side into which the outside air containing fine dust flows, as shown in FIG. It is formed on the outer surface through which the purified air passes.

The air-conditioning filter of the present invention in the form of a combination of a nonwoven fabric layer and a foam layer having a density distribution as described above satisfies MERV 9 to 12 shown in the ASHRAE standard 52.2 test chart shown in Table 2 above, and is the best residential, high-end commercial. It has the function of high efficiency prefilter that can be used in building, hospital, office, laboratory, etc.

As shown in FIG. 3 (a), the air-conditioning filter provided in the present invention is composed of a material such as a nonwoven fabric, and a highly efficient pre-filter form in which a foam layer made of a resin foam having a predetermined thickness is laminated thereon. Consists of

In particular, the foam layer is composed of a resin foam having three-dimensional micropores, and as the three-dimensional structure of the resin foam is well formed, the overall shape is simple, but also excellent dust and fine particles can be removed at the same time. It becomes possible to exercise.

For example, in the case of the nonwoven fabric layer constituting the filter medium, dust removal of 3 μm or more is possible, and in the case of a nonwoven fabric layer made of a resin foam having a three-dimensional structure, dust removal in the range of 1 to 3 μm is possible.

In addition, by providing a form in which a separate nonwoven fabric is further laminated and combined with the foam layer, a more excellent function for removing fine dust in the range of 1 to 3 μm can be exhibited.

On the other hand, the method of manufacturing the air conditioning prefilter of the present invention for achieving the above object will be described in detail for each step as follows.

The air conditioning filter having the three-dimensional micropores as described above is manufactured through 1) preparing a foam (foam), 2) coating the resin foam, and 3) drying.

1) Preparation step for resin foam

First, an emulsion solution is prepared. The emulsion solution for the preparation of the resin foam is based on a water-soluble resin, it is preferable to uniformly mixed with a filler, a foaming agent, a foam stabilizer, a dispersant, and the like, and then to thicken it with a thickener.

In this case, the water-soluble resin may be one or a mixture of two or more selected from acrylic resin, NBR latex, natural latex, silicone rubber, water-soluble urethane and fluorine resin.

The filler may be a filler commonly used in the art, for example, talc, silica, aluminum hydroxide and the like. As the foaming agent, a surfactant may be selectively used, and sodium lauryl sulfate (SLS), which is a surfactant of a linear alkyl derivative having 12 carbon atoms, may be used. The foam stabilizer may be used ammonium stearate or silicon, preferably, it is preferable to use the above ammonium stearate and silicon in order to ensure microbubble generation, foam holding ability, fluidity, film strength and the like. As said dispersing agent, the dispersing agent etc. which have a polycarboxylic acid soda salt as a main component can be used, It is preferable to use the acryl-type thickener as said thickener.

In order to uniformly mix the emulsion solution, stirring is necessary, but heat is generated in the emulsion solution when stirring, and the crosslinking agent proceeds to crosslink the emulsion solution during the mixing process, thereby decreasing the fluidity of the emulsion solution. . Therefore, in the present invention, the crosslinking agent is not added when the emulsion solution is mixed, but is added through a separate supply pipe during the manufacture of the resin foam. As said crosslinking agent, an amide type and an epoxy type can be used.

The emulsion solution is stirred in a bubble generator to form a resin foam.

For example, after blowing air in the state where the emulsion solution is put into the bubble generator, the mixture is stirred to form a resin foam. The resulting resin foam has a diameter in the range of 10 to 15 μm, preferably in the range of 13 to 14 μm. Adjusting to maintain is good in terms of foam stability and porosity.

For the supply of the emulsion solution, a conventional pump may be used, and preferably, a mono pump capable of uniformly supplying a constant amount at all times regardless of the conditions of the installation may be used.

The air pressure supplied to the bubble generator must be higher than the pressure inside the bubble generator, so that the air can be uniformly diffused into the emulsion solution inside the bubble generator.

The bubble generator may form a smaller size of the resin foam as the stirring speed is faster, but if the stirring speed is too fast, the bubbles formed by the bubbles can grow together, the control of the speed is required, in the case of the present invention Is adjusted to 100 to 500 rpm, preferably 250 to 350 rpm. In addition, the size of the resin foam can also be adjusted by the number of pins of the bubble generator, the larger the number of pins can form a smaller size of the bubble, the number of pins 200 to 300, preferably 250 to 300 bubble generator It is good to use

2) Resin Foam Coating

In this step, the step of coating a resin foam on the nonwoven fabric (media) layer. The coating knife allows the foam to be evenly coated, and the foam is discharged in a manner of reciprocating 10-30 times per minute with the bubble feeding nozzle in the transverse direction of the media traveling direction.

In this step, the resin foam, once produced, is applied to the surface of the filter medium in a state in which the bubble shape is maintained so that the resin foam is laminated on the surface of the filter medium as a network structure. It is desirable to allow the stack to be 0.3 mm thick.

By discharging the foam at a high speed of reciprocating 10-30 times per minute by making the foam supply nozzle of the foam coater in the transverse direction of the media traveling direction, the time required for the foamed foam to be coated on the media in the structure of the conventional foam coater It can be shortened, and thus there is an advantage that can maintain a fine bubble.

In this way, by rapidly supplying the resin foam by using the rapidly reciprocating bubble supply nozzle, it is possible to prevent the phenomenon that the average diameter of the fine bubbles increase with time. In the air-conditioning filter produced through this step, the average diameter of the foam is formed in the range of 1 to 3㎛.

In particular, by disposing a separate nonwoven fabric on the filter medium during the coating of the resin foam and then discharging the resin foam thereon, it is possible to exhibit a more improved dust removal function through the combination of the foam layer and the nonwoven fabric of the resin foam.

3) drying step

This step is to dry the filter medium coated with the resin foam, it is carried out divided into the following process.

In order to prevent the foamed media from expanding and breaking rapidly during foam drying, the coated surface is gelled for 30 seconds to 1 minute with a gentle wind of 85 to 95 ° C. (less than 1 m / sec wind speed) (gelling process). . The gelled media is dried at a temperature of 120 to 150 ° C. for 1 to 3 minutes (drying process). As described above, the dried coating material is heat-treated at a temperature of 150 to 160 ° C. for 20 seconds to 2 minutes (heat treatment process).

The dried media through this process can maintain fine bubbles in the range of 10 to 15 ㎛ average diameter.

On the other hand, the apparatus for manufacturing the air conditioning prefilter as described above is as follows.

As shown in FIG. 4, the bubble generator 10 is fixed to the stator 16 forming the outer wall, the rotor 17 at the center thereof, and perpendicular to the rotor 17, and has a thickness of 4 to 5 mm. Inverter side pins, stator side pins fixed to the stator 16 and having a thickness of 4 to 5 mm, and emulsion liquid supply pipes installed at the upper end of the stator 16 to feed raw materials into the stator 16 ( 18), the pneumatic supply pipe 19, the crosslinking agent supply pipe 20, and the like.

Therefore, while the rotor 17 rotates at a speed of 100 to 500 rpm, the raw materials supplied through the emulsion liquid supply pipe 18, the pneumatic supply pipe 19, and the crosslinking agent supply pipe 20 installed at the upper end of the stator 16 are mixed. It will generate resin bubbles.

In addition, the foam coater 11 is a foam supply nozzle 12 for supplying the resin foam 13 generated in the foam generator 10 to the filter medium 14, the roller 15 for transporting the filter medium 14 In order to uniformly coat the resin foam 13 coated on the filter medium 14, a coating knife (not shown) positioned vertically on the filter medium is formed.

The bubble supply nozzle 12 is installed in the transverse direction of the medium 14 traveling direction, and discharges the resin foam to the medium 14 at a rate of 10 to 30 times of reciprocation per minute.

Therefore, the resin foam 13 supplied to the filter medium 14 through the bubble supply nozzle 12 is uniformly coated on the filter medium by a coating knife located outside the foam coater 11.

The filter of the present invention manufactured through such a device is a three-dimensional structure including three-dimensional micropores by coating a resin foam having an average diameter of 10 to 15㎛ on the surface of the nonwoven fabric as a filter, and drying the coated resin foam It will have a, so that when used as an air conditioning pre-filter it is possible to more effectively collect the large dust and fine dust.

Hereinafter, the present invention will be described in more detail with reference to Examples, but it is obvious that the present invention is not limited by the following Examples.

Example  1-3 and Comparative example  1 to 2

1) Preparation of resin foam

80 parts by weight of acrylic resin as water-soluble resin, 10 parts by weight of talc as filler, 2 parts by weight of sodium lauryl sulfate as foaming agent, 5 parts by weight of ammonium stearate foam stabilizer as foam stabilizer, 1 part by weight of silicone foam stabilizer, polycar as a dispersant 0.5 weight part of sodium acid salts (50%) were mixed uniformly, 1 weight part of sodium alginate was added as a thickener, and the emulsion liquid was prepared.

The emulsion solution was fed to the bubble generator by the apparatus shown in FIG. 1 at a rate of 60 kg / h, and 1 part by weight of isocyanate-based as a crosslinking agent was injected through a separate feed pipe. At this time, the compressed air (6 kg /) of the bubble generator to the flow meter (flow meter) value to 10 cc / min, and stirred at 250 rpm to produce a foam of the resin.

2) Resin Foam Coating

After the resin foam produced through the apparatus of FIG. 4 was introduced into the foam coater as described above, the nonwoven fabric layer was foamed through a supply nozzle having a reciprocating speed of 30 times / min and a distance of 6 m from the foamer to the supply nozzle. It was. At this time, the speed of the nonwoven fabric was 6 m / min. The time from foaming to coating took 30 seconds.

3) drying step

The low-density nonwoven fabric coated with the foam is treated with a mild wind of 90 ° C. (within 10 m / sec) for 1 minute to gel the foam on the coating surface, and dried for 2 minutes with a strong wind of 130 ° C. (within 30 m / sec). , And heat treatment at 160 ℃ for 2 minutes to prepare an air conditioning filter.

Experimental Example  One

Characteristics of the nonwoven fabric layer and the foam layer constituting the air conditioning prefilters prepared in Examples 1, 2, and 3, and the characteristics of a commercial air conditioning prefilter [Comparative Example 1] and a commercial medium filter [Comparative Example 2] Is shown in Table 3 below.

In addition, the average air permeability before and after the resin foam coating of the commercial filters of Examples 1, 2 and 3 and Comparative Examples 1 and 2 and the filtration efficiency of 1 to 3 ㎛ dust was measured by a method known in the art the following table 3 is shown.

As the nonwoven fabric layer, a low melting point (LM) yarn and a polyethylene terephthalate yarn were used for a density of 50 to 200 g / m 2 × 1 mmT, and a polyethylene terephthalate yarn (PET) was used for a density of 300 g / m 2 × 1 mmT.

 division  Example 1  Example 2  Example 3 Comparative Example 1 (Existing Prefilter) Comparative Example 2 (Existing Medium Filter) ²⁾ Before coating After coating Before coating After coating Nonwoven Density (g / ㎡ × 1mmT) Lowest density layer 50 50 50 80 80 300 300 Highest density layer 200 200 200 250 250 Nonwoven Thickness ^{3 )} (mm) Lowest density layer 0.5 One 1.5 One One 1.0 1.0 Highest density layer 0.2 0.4 0.6 0.5 0.5 all 1.5 3 4 2 2 Foam Average Diameter (㎛) 12 12 12 - 12 - 12 Foam layer thickness (mm) 0.2 0.2 0.2 - 0.2 - 0.2 Boundary thickness ^{1 )} (mm) 0.2 0.4 0.6 - 0.1 - 0.05 Average air permeability (cm 3 / cm 2 / sec) 120 80 50 120 50 30 15 Gross weight of filter media (g / ㎥) 180 230 270 200 230 300 320 1 ~ 3㎛ dust filtration efficiency 68% 77% 90% 58% 77% 90% ↑ - 1) The thickness of resin foam in the voids of the nonwoven fabric layer. 2) Uniform density distribution. 3) The density of nonwoven fabric is gradually dense.

Average air permeability is a factor that greatly affects the dust collection amount (D, H, C) and filtration efficiency of the filter medium. Comparing Example 2 and Comparative Example 1, the air permeability after coating shows a lot of differences, respectively, 80 cc and 50 cc, but it can be seen that the dust filtration efficiency is the same as 77%. This is an indirect result indicating that Example 2 is a low differential pressure filter.

The reason for the difference in air permeability as described above is that in the case of existing prefilters, an acrylic or urethane spray process is introduced in order to increase the surface density very high, or the density of the low melting fiber is made high, and then the bulky fibers on the surface are heated by a press. Since a process of increasing the uniformity by thermal fusion is introduced, the porosity of the nonwoven fabric layer is relatively low, thereby lowering the air permeability.

Comparing the results before coating of Example 1 and Comparative Example 1 it can be seen that the air permeability is the same, but the dust filtration efficiency of the filter shows a lot of difference. This is an example showing that the foam coating process can produce a filter of higher efficiency than the acrylic or urethane spraying process or the hot press calendering process.

Meanwhile, an electron micrograph of the air conditioning prefilter manufactured in Example 2 is shown in FIG. 5. According to Figure 5 it can be confirmed that the fine bubbles having a uniform size between the non-woven fabric voids is formed stably.

Experimental Example  2

At present, the air-conditioning standard for general air conditioning prefilters is 70 to 150 cc. Accordingly, the microdust removal efficiency of the air conditioning prefilter prepared in Example 2 and the prefilter before coating of the conventional Comparative Example 1 was compared, and the results are shown in the graph of FIG. 6.

At this time, the concentration of fine dust-containing air used is the American Air-Conditioning Association (ASHRAE) standard standard dust, and passed the low density nonwoven fabric and the air conditioning filter, which is a test body at a flow rate of 0.9 cm / sec on average [pass direction: nonwoven fabric layer → foam layer ].

According to the graph of Figure 6, after the coating it can be seen that the dust removal efficiency is improved by about 30% than before the coating.

In the case of the air conditioning prefilter having the three-dimensional micropores provided by the present invention, MERRA 9 to 12 presented in the ASHRAE standard 52.2 shown in Table 2 is satisfied. Effective application in the field is possible.

In addition, the filter provided in the present invention can be applied to a pre-filter for general air conditioning or industrial air conditioning, and can also be applied to a bag filter, a bent filter, and the like.

As described above, the present invention provides the following effects by implementing a three-dimensional microporous filter that can effectively remove the fine dust in the range of 1 to 3㎛ by coating the micropores on the filter medium.

First, the filter is very economical because the price is very low, the efficiency is high, and the manufacturing process is simple.

Second, it is possible to manufacture high-efficiency prefilters that satisfy the ASHRAE test criteria MERV of 9-12, so that it can be widely applied to various fields such as the best residential, high-grade commercial buildings, hospitals, offices, and laboratories.

Third, due to the excellent MERV value, it is able to actively cope with the gradually increasing air quality standards.

Fourth, the filter has a low differential pressure characteristic while showing a filtration efficiency comparable to that of the medium filter among air conditioning filters.

Claims (8)

It is formed on one side in contact with the incoming outside air, and gradually increases in density along the direction in which the outside air is discharged from the contact surface into which the outside air flows, with a minimum density of 50 g / m 2 × 1 mmT and a maximum density of 200 g / m 2. A bulky nonwoven layer exhibiting a density distribution of up to 1 mmT; A pre-filter for air conditioning having three-dimensional micropores, which is formed on the outer surface of the nonwoven fabric layer and has a structure in which a foam layer in which pores in an average range of 10 to 15 μm forms a three-dimensional network structure is laminated. . The method according to claim 1, The nonwoven fabric layer has a three-dimensional micropores, the pre-filter for air conditioning, characterized in that the thickness showing the lowest density ranges from 25 to 50% of the total thickness. The method according to claim 1, The nonwoven fabric layer has a three-dimensional micropores, the pre-filter for air conditioning, characterized in that the thickness showing the highest density is in the range of 10 to 50% of the total thickness. The method according to claim 1, The nonwoven fabric layer has a three-dimensional micro-pores, air conditioning pre-filter, characterized in that the total thickness ranges from 1.5 to 5 mm. The method according to claim 1, The foam layer is a pre-filter for air conditioning having three-dimensional micropores, characterized in that consisting of a dual structure including a nonwoven fabric. The method according to claim 1, The foam layer is a pre-filter for air conditioning having three-dimensional micropores, characterized in that the total thickness ranges from 0.5 to 1 mm. The method according to claim 1, The filter in the form of a combination of the nonwoven fabric layer and the foam layer has three-dimensional micropores, characterized in that it has a step-by-step filtration performance from the first large dust to small dust (diameter 10 ㎛ or more → 3 ~ 10 ㎛ → 1 ~ 3 ㎛) Air conditioning prefilter having a. The method according to claim 1, The air filter pre-filter having three-dimensional micropores, characterized in that the filter is a combination of the nonwoven fabric layer and the foam layer exhibits MERV (Minimum Efficiency Reporting Value) 9-12.

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