KR100749966B1 - Air filter media with antibacterial property - Google Patents

Abstract

An antibacterial air filter material which has excellent antibacterial property and filtering capability, is low in environmental harmfulness, and simplifies the manufacturing process by comprising a nano-fiber web in which fibers with an average diameter of 1,000 nm or less are laminated in the form of a web is provided. An antibacterial air filter material comprises nano-fibers with an average diameter of 1,000 nm or less which are formed from a mixed resin of polyamide and chitosan, and are laminated in the form of a web. The average diameter of the nano-fibers is 50 to 800 nm. The chitosan has the degree of deacetylation of 70 to 100%. The nano-fibers are manufactured by electrospinning a spinning solution obtained by dissolving a mixed resin of polyamide and chitosan into an aqueous formic acid solution. The antibacterial air filter material is laminated on a fiber substrate selected from the group non-woven fabric, woven fabric and knitted fabric. The antibacterial air filter material is laminated on the fiber substrate in a single layer or a multi-layer.

Description

Air filter media with antibacterial property

1 is a process schematic diagram of an example of manufacturing the antimicrobial air filter material of the present invention.

Figure 2 is an electron micrograph of the surface of the antimicrobial air filter material (nanofiber web) according to the present invention.

* Explanation of symbols on the main parts of the drawings

1: spinning liquid main tank 2: metering pump 3: nozzle

4 collector 5 voltage transfer rod 6 voltage generator

The present invention relates to an antimicrobial air filter material, more specifically, the antimicrobial and filtering ability, including a nanofiber web in which fibers having an average diameter of 1,000 nm or less (hereinafter referred to as "nano fibers") are laminated in the form of a web. The present invention relates to an antimicrobial air filter material which is excellent in environmental resistance and has a simple manufacturing process.

The demand for air filter materials is rapidly increasing due to industrial development, natural pollution, and the increase of special applications. The development of the industry has led to the increase of various fine dusts. These fine dust enters the human body through the respiratory system of the human body and is discharged or not discharged and accumulates, causing a serious disease after a long time. These fine dusts are dust with a diameter of about 1 μm or less and are so small and small that we cannot see them. Fine dust penetrates deep into the alveoli of a person, which is a direct cause of various respiratory diseases and reduces the body's immune function. Since these fine dusts are mainly generated by the combustion action, they consist of ionic components such as sulfate, nitrate and ammonia, and harmful substances such as metal compounds and carbon compounds.

More than 70% of the fine dust in large cities comes from automobile exhaust, which is more strictly regulated than ordinary dust. However, due to the development of the automobile industry, the influence of these fine dust is increasing day by day.

In addition, yellow dust, which occurs in China, causes various diseases such as visibility disorders, respiratory diseases, eye diseases, and allergies. Furthermore, the fine particles contained in the yellow dust cause chemical reactions in the atmosphere to produce various oxides, which worsen chronic bronchitis in smokers and cause respiratory diseases of the elderly and infants. Recently, due to industrialization in China, it is estimated that it contains heavy metals such as lead and cadmium and harmful pollutants such as carcinogens.

Due to this increasing pollution of the air, the demand for air filtration everywhere in humans has increased at a faster rate in recent years. Home air purifiers are already widely used and used, and the air flowing into the interior of automobiles is also increasingly supplied through filters. In addition, air is filtered and supplied almost everywhere, including schools, companies and factories.

The air supplied through the air filter material needs to filter out the fine dust, yellow dust, pollen, etc. as described above, and also to filter out harmful bacteria, and in particular, to prevent the filtered bacteria from multiplying and causing secondary damage on the filter. Special attention should be given to the antimicrobial properties.

Conventional antimicrobial air filter material has been produced by applying an antimicrobial material to the existing air filter material. Thus, the manufacturing process consists of a two step process. That is, it is a method of manufacturing an air filter material using a fiber assembly, and applying various organic and inorganic mechanical antibacterial agents to it. The antimicrobial air filter material produced by this method has a disadvantage in that the antimicrobial agent is detached. In addition, there is a disadvantage that the antimicrobial particles fill a significant gap of the air filter material and the amount of filtration falls. In addition, an expensive antimicrobial agent must be used, and there is a disadvantage in that a high cost occurs according to the two-step process.

On the other hand, Korean Patent Laid-Open Publication No. 1999-0023143 discloses a method for preparing an antimicrobial air filter material by adsorbing chitosan having antimicrobial properties on an existing air filter material, and Korean Patent Laid-Open Publication No. 2001-0095335 containing chitosan A method of manufacturing a water filter cartridge filter is disclosed, and Korean Patent Registration No. 10-0315334 discloses a method of processing a polyester fabric with low molecular weight chitosan.

However, when manufacturing antibacterial air filter material using chitosan, the price of chitosan is cheaper than inorganic antibacterial agent, but when low molecular weight chitosan is attached to polyester fabric for application to polyester fabric, polyester and chitosan adhesive strength There is a high possibility that chitosan, which should exhibit antibacterial activity, will be lost due to lack.

In the case of manufacturing the antimicrobial air filter material by adsorbing chitosan, chitosan occupies the pores of the air filter material, so the antibacterial property is excellent but the air filtration amount is disadvantageous.

In order to compensate for these disadvantages and to secure antimicrobial properties while filtering a large amount of air, a technique for producing an antimicrobial filter using nanofiber manufacturing technology by electrospinning has been proposed. Korean Patent Registration No. 10-0536459 shows an antimicrobial nanofiber prepared using silver nitrate and cellulose acetate, and Korean Patent Laid-Open Publication No. 2005-0032656 introduces a method for producing a nanofiber web through electrospinning of chitin or chitosan.

However, in the case of using silver nitrate and cellulose acetate as in Korean Patent Registration No. 10-0536459, not only the handling of silver nitrate is required but also acetone is used as a solvent. Thus, volatilized solvents generated during the electrospinning process must be thoroughly recovered. Special care must be taken in management, as sparks can cause ignition and fire. In addition, in the nanofibers by electrospinning of chitin or chitosan, as in Korean Patent Laid-Open Publication No. 2005-0032656, chitosan nanofibers are very suitable as a wound coating material, but because they consist of chitosan only, mechanical properties are weak and unstable.

On the other hand, ULPA filter made of glass fiber is developed and used to effectively block fine dust, but glass fiber dust is generated during filter manufacturing and environmental pollution problem occurs seriously when disposed. There was a problem.

The present invention has excellent antimicrobial properties without using a separate antimicrobial agent to solve such conventional problems, easy to filter, adsorption and collection of fine dust and bacteria, high air permeability, less environmental hazards, manufacturing The process is simple and the manufacturing cost is to provide a low cost air filter material.

To this end, the present invention provides an air filter material in which polyamide-chitosan nanofibers having an average diameter of 1,000 nm or less are laminated in a web form or an air filter material in which the nanofiber web is laminated on a fiber substrate.

The antimicrobial air filter material of the present invention for achieving the above problems is characterized in that the nanofibers composed of a mixed resin of polyamide and chitosan with an average diameter of 1,000 nm or less are laminated in a web form.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

When the air filter paper is manufactured using the nanofibers by the electrospinning of the present invention, as compared with the conventional general air conditioner filter, the fine dust of about 1 μm in diameter can be filtered with high efficiency as well as the fine dust of about 1 μm. High-efficiency filter to filter the material is composed of glass fiber, there is a possibility of environmental pollution, but the antimicrobial air-conditioning filter of the present invention is very low possibility of environmental pollution because it does not use glass fiber.

In addition, compared to the nanofiber filter produced by electrospinning for the purpose of filtration of fine dust and bacteria, chitosan is mixed with polyamide simultaneously without using an antibacterial agent, so the process is simple and the solvent is inexpensive and environmentally friendly. Low risk and very economical. At the same time, compared to the high efficiency air-conditioning filter using inorganic antimicrobial agents and nanofibers, there is no micropore clogging of the nanofibers by the inorganic antimicrobial agents, and the filtration amount of air can be maximized.

The antimicrobial air filter material of the present invention can be produced by electrospinning the spinning solution consisting of a mixed resin of polyamide and chitosan as shown in FIG. 1 is a process schematic diagram of an example of manufacturing the antimicrobial air filter material of the present invention. The air filter material of the present invention is composed of nanofibers having an average diameter of 1,000 nm or less, and the nanofibers exist in a web state such as a nonwoven fabric to form a myriad of fine pores. Due to the numerous pores of the nanofiber web, it is possible to expect effective filtration of fine dust of 1,000 nm or less, which is difficult to expect in an air filter material composed of conventional fiber polymers. In addition, the antibacterial effect of chitosan can prevent side effects due to propagation of bacteria filtered by the air conditioning filter. In addition, by simultaneously electrospinning polyamide and chitosan, it is possible to simultaneously obtain micropores by antimicrobial properties and nanofibers in only one step spinning process. The air filter material of the nanofiber web of the present invention has extremely low environmental pollution compared to glass fiber as the material of the high efficiency filter for filtering fine dust of about 1,000 nm.

The present invention is not particularly limited to the electrospinning apparatus for producing the antimicrobial air filter material. As shown in FIG. 1, an electrospinning apparatus using multiple nozzles may be used, and other types of electrospinning apparatuses may also be used. The electrospinning apparatus comprises a spinner comprising a metering pump (2) for supplying a polymer solution and a plurality of nozzles (3), a high voltage generator by the high voltage generator (6) and a collector for fixing the nanofibers that are spun and volatilized ( 4) consists of. The generated voltage for spinning the nanofibers of the present invention is variously applied in consideration of the concentration of the polymer solution, the amount of the polymer solution supplied through the metering pump (2), the thickness of the nanofibers to be obtained, etc. can do. The nanofiber web may be directly laminated or coated onto the fiber substrate by electrospinning while passing the fiber substrate over the collector 4. As the fiber base, a fiber base composed of cotton fibers may be used, and a fabric or nonwoven fabric composed of polyester or nylon may also be used. Therefore, an air filter material composed of conventional fiber polymers may be used as the fiber base material.

The polymer used in the production of the antimicrobial air filter material by the nanofiber web of the present invention uses polyamide and chitosan. As a solvent for electrospinning, it is preferable to use a formic acid aqueous solution of 50 to 100% concentration. That is, polyamide and chitosan are simultaneously dissolved in 50% to 100% concentration of formic acid solution to prepare a spinning solution, and then supplied to the electrospinning apparatus as shown in FIG. Preferably, in consideration of the solubility of the polyamide, using a formic acid aqueous solution of 70 ~ 100% concentration, it is effective to apply heat to about 30 ~ 60 ℃ to increase the dissolution rate. The nanofibers prepared by this method are present with polyamide nanofibers and chitosan nanofibers at the same time, thereby providing antimicrobial activity by innumerable micropores and chitosan nanofibers by the nanofiber web. The concentration of the mixed polymer in the spinning solution may be 1 to 50%, but considering the productivity in the actual process and the solubility in the solvent, it is appropriate to dissolve it in the concentration of 10 to 30%. The mixing weight ratio of polyamide and chitosan in the spinning solution ranges from 1: 1 to 5: 1. That is, the same amount of polyamide and chitosan may be mixed and used, or the polyamide may be mixed and used so that the content of 5/6 and chitosan is 1/6. When chitosan is more than polyamide, the properties of the nanofiber web produced are weak, so that it is not easy to handle in the form of a filter by attaching it to a nonwoven fabric or fabric for use in an air filter and processing it. In addition, when the content of chitosan is lower than 1/6 in the mixed polymer, the content of chitosan is low and the antimicrobial activity is lowered. There is no restriction on the molecular weight of the polyamide or chitosan used, and there are no restrictions on additives such as quencher and ultraviolet stabilizer. Chitosan preferably has a degree of deacetylation of 70% or more. In other words, chitosan having a deacetylation degree of less than 70% is poorly soluble in formic acid aqueous solution, which is likely to cause undissolved in the polymer solution, which may be a barrier to the spinning process. Formic acid, which is used as a solvent, is economical because it has less environmental pollution and is cheaper than other organic solvents. In addition, as compared with the preparation of the antimicrobial nanofiber web using an inorganic antimicrobial agent such as a silver antimicrobial agent, the use of chitosan is economical, and there are no disadvantages such as clogging of micropores of the nanofibers by the antimicrobial agent.

The prepared mixed polymer solution is electrospun using the electrospinning apparatus as shown in FIG. 1. A metering pump is used to feed the polymer solution and generate a high voltage so that the nanofibers are generated and spun onto a collector to produce a nanofiber web.

The thickness of the nanofiber web in the present invention is not limited. That is, it is possible to freely obtain and use the required level of thickness by slowing down the winding speed of the collector or adjusting the amount of nanofibers radiated.

According to the present invention, an antimicrobial air filter material in which a nanofiber composed of polyamide and chitosan mixed resin is laminated in a web form is laminated on a single layer or a multilayer on a conventional fiber substrate or an existing air filter member. It includes an antimicrobial air filter material of the structure.

The fiber base is one selected from the group consisting of nonwoven fabrics and knitted fabrics.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example  One

A nanofiber web was prepared using an electrospinning device in the form as shown in FIG. 1, but polyamide and chitosan were dissolved in an aqueous 75% formic acid solution to prepare a spinning solution, which was then injected into an electrospinning apparatus to prepare a nanofiber web.

Polyamide is a polyamide resin with a relative viscosity of 2.5 and chitosan has a 95% deacetylation degree. The polyamide and chitosan were mixed at a weight ratio of 5: 1 to prepare a mixed polymer, which was dissolved in a formic acid solution at a concentration of 20% (w / w) to prepare a spinning solution.

The prepared mixed polymer solution was supplied to the nozzle using a metering pump of an electrospinning apparatus. The voltage applied to the electrospinning was 28,000 volts and the metering pump was properly adjusted to ensure that the mixed polymer solution did not form nanofibers at the nozzle and did not fall off.

The formed nanofiber web was laminated on a conventional air filter material in the form of a polyester nonwoven fabric to prepare an antimicrobial air filter material.

Example  2 to Example  8

As in Example 1, except that the mixing ratio of the mixed polymer, the concentration of the mixed polymer solution, the formic acid concentration of the formic acid aqueous solution, the voltage generated in the high voltage generator, the concentration of the solution, and the voltage generated in the high voltage generator were changed as shown in Table 1. An antimicrobial air filter material was prepared.

Example RV DA (%) Formic acid concentration% (w / w) Polymer concentration in spinning solution% (w / w) Polymer Mixing Ratio (PA: CS) Voltage (V) Collector rotation speed (m / min) Example 2 2.6 95 95 20 1: 1 3.2 million 0.5 Example 3 2.5 88 80 15 3: 1 2.8 million 0.5 Example 4 3.1 85 80 10 4: 1 3.0 million 0.5 Example 5 2.5 92 70 25 5: 1 3.2 million 0.4 Example 6 2.7 75 70 30 4: 1 2.7 million 0.3 Example 7 2.6 77 70 15 4: 1 2.5 million 0.5 Example 8 2.5 70 70 20 3: 1 3.1 million 0.5

In the above table, RV is the relative viscosity of polyamide and DA is the deacetylation degree of chitosan. The concentration of the formic acid aqueous solution used as the solvent and the concentration of the polymer in the spinning solution are both calculated in% (w / w). It is more advantageous to adjust the temperature of the dissolution tank to 40 ~ 60 ℃ in order to increase the rate of dissolution during dissolution of the mixed polymer. In the mixing ratio of the mixed polymer, PA means polyamide and CS means chitosan. The mixing ratio is weight ratio. That is, when PA: CS is 5: 1, it can manufacture by mixing 500 g of polyamides and 100 g of chitosan. The rotational speed of the collector is the winding speed of the nanofiber web.

Comparative Example  One

A spinning solution prepared by dissolving a polyamide having a relative viscosity of 2.5 at a concentration of 20% in an aqueous 75% formic acid solution was formed on a conventional air filter material in the form of a polyester nonwoven fabric passing through a collector using an electrospinning device as shown in FIG. Electrospinning produced an antimicrobial air filter material.

Comparative Example  2

A spinning solution prepared by dissolving a polyurethane resin in a concentration of 20% in dimethylformamide was electrospun onto a conventional air filter material in the form of a polyester nonwoven fabric passing through a collector using an electrospinning device as shown in FIG. A filter material was prepared.

For the air filter material obtained through the above examples and comparative examples, the filtration efficiency and antimicrobial activity, fine air permeability, and the presence of environmental pollution after using the filter was evaluated by the following method.

Filtration efficiency

It is evaluated according to the commonly used ASHRAE 52.2-1999 standard. The filter performance device of the ASHRAE 52.2 consists of a test particle supply and a flow duct, which is equipped with an external inlet air cleaning filter, a rectifying grating and an orifice, a pressure loss measuring unit and a flow rate measuring unit. The belmouth, point spreader and commutation grating in the ducts facilitate the flow of air and provide uniform mixing and diffusion of test particles. The test particle collection tube shall be attached to a position where the particles are uniformly mixed. The unit fixing shall be flanged to secure the test agent on four sides. The positive pressure difference between the upstream and downstream sides of the test specimen is measured by an inclined manometer, and one positive pressure hole is provided at each of the upstream and downstream sides of the duct diameter from the unit fixing part. In addition, the orifice flowmeter specified in KS B 6311 is to be installed in the airflow flow rate measuring unit. Test particles are usually supplied in a specific size in a generator using a pressure spray nozzle.

Filtration efficiency is expressed as a percentage, and the filtration efficiency is measured by measuring the concentration of air particles supplied through the filter (Ic) through a probe installed in the measuring instrument (Ic) and measuring the concentration of air particles passing through the filter ( Oc) to obtain the formula below.

When evaluated in this way, the air-conditioning filter paper composed of ultra-fine synthetic fibers or glass fibers showed about 60 ~ 80% of filtration efficiency, and 99.95% of HEPA filter and 99.99% of ULPA filter, which is high efficiency filter, showed filtration efficiency. do.

Antibacterial

Antimicrobial activity was evaluated by the bacteriostatic reduction rate. The bacteriostatic reduction rate was measured by the antimicrobial measurement method of Korean Industrial Standard KS K 0693-2001. The reduction rate is obtained using the number of bacteria. The initial bacterial count is 1.4 × 10 ⁵ / ml for staphylococci and 1.3 × 10 ⁵ / ml for pneumococci.

Breathable

Breathability was measured according to JIS L 1096-A standard. That is, the amount of air passing through the air by applying a pressure of 125 Pa to the filter surface of the area 38cm ² is measured and expressed in units of cm ³ / cm ² / s. The air permeability of the filter was set to 1, and the air permeability of the other examples and the comparative examples was expressed by relative values.

Environmental pollution due to filter disposal

The problem of environmental pollution caused by the disposal after the use of the filter was evaluated only as a complete incineration (no) or impossible (presence).

division Filtration efficiency (%) Bacteriostatic reduction rate (%) Breathable Pollution Example 1 98.5 99 2.1 radish Example 2 99.1 96 1.9 radish Example 3 98.9 95 2.1 radish Example 4 99.1 95 2.3 radish Example 5 98.5 96 1.8 radish Example 6 96.7 97 1.9 radish Example 7 97.3 95 1.8 radish Example 8 96.9 95 1.7 radish Comparative Example 1 98.5 22 2.1 radish Comparative Example 2 92.3 35 1.2 radish

The above table is a result of evaluating the filtration efficiency, antimicrobial properties, air permeability, environmental pollution by the above method for the air-conditioning filter paper of the Examples and Comparative Examples.

As shown in the table above, the air-conditioning filter by nanofibers prepared by electrospinning using the polyamide and chitosan of the example was found to be suitable for all of the filtration efficiency, antibacterial, breathable, environmental pollution. That is, the filtration efficiency was very high, more than 95%. Therefore, in terms of filtration efficiency, it can be used in an air conditioning filter that should effectively remove fine dust. In addition, as the bacteriostatic reduction rate of more than 95% in bacteriostatic reduction rate was also shown to be excellent antibacterial. In addition, the breathability is 1.7 to 2.3 times higher than that of the high-efficiency filter manufactured using the glass fiber of the comparative example. In addition, in the environmental pollution caused by the disposal after the use of the filter, all the filters of the embodiment can be completely incinerated, so that the burden of environmental pollution is low.

In Comparative Example 1, there is no chitosan, so the filtration efficiency and air permeability are almost the same, but the antibacterial property is extremely insufficient.

In Comparative Example 2, a polyurethane is used as a polymer and dimethyl formamide is used as a solvent. As a result, the diameter, pore size, and distribution of the nanofibers are different, resulting in lower air permeability and lower filtration efficiency.

The antimicrobial air filter material of the present invention is composed of nanofibers prepared by electrospinning, but the materials constituting the nanofibers are polyamide and chitosan, which have excellent antimicrobial properties and exhibit excellent filtration ability even for fine dusts of 1,000 nm or less in diameter. At the same time, instead of producing polyamide nanofibers and chitosan nanofibers in two stages, they are manufactured simultaneously in a single spinning process, making the process simple, inexpensive, and using formic acid and water as solvents for electrospinning. It is very advantageous for production control because it is less environmentally harmful and does not use flammable materials.

The nanofibers used in the present invention are composed of ultra-fine fibers having a diameter of 1,000 nm or less, and numerous fine pores are present on the nanofiber web, so that the adsorption and filtration of fine dust through the fine pores is very excellent. At the same time, by using chitosan with excellent antimicrobial activity, it is possible to prevent secondary contamination of the filter by antibacterial action against the filtered bacteria.

Claims (10)

An antimicrobial air filter material having an average diameter of 1,000 nm or less and nanofibers composed of a mixed resin of polyamide and chitosan laminated in a web form. The antimicrobial air filter material according to claim 1, wherein the average diameter of the nanofibers is 50 to 800 nm. The antimicrobial air filter material according to claim 1, wherein the degree of deacetylation of chitosan is 70% to 100%. The antimicrobial air filter material according to claim 1, wherein the nanofibers are prepared by electrospinning a spinning solution in which polyamide and chitosan mixed resins are dissolved in an aqueous formic acid solution. The antimicrobial air filter material according to claim 4, wherein the mixed weight ratio of polyamide: chitosan in the spinning solution is 1: 1 to 5: 1. The antimicrobial air filter material according to claim 4, wherein the concentration of the polyamide and chitosan mixed resin in the spinning solution is 1 to 50%. An antimicrobial air filter material according to claim 1, wherein the antimicrobial air filter material is laminated on a fiber substrate. 8. The antimicrobial air filter material according to claim 7, wherein the fiber base material is one selected from the group consisting of nonwoven fabric, woven fabric and knitted fabric. The antimicrobial air filter material according to claim 7, wherein the antimicrobial air filter material is laminated in a single layer on the fiber substrate. The antimicrobial air filter material according to claim 7, wherein the antimicrobial air filter material is laminated in a multilayer on the fiber substrate.

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