KR102466228B1 - Air mask filter and manufacturing process of the same - Google Patents

Abstract

The present invention relates to an air filter fabric manufactured based on a natural polymer material by inducing the porosity of the film through an enzymatic reaction to increase the surface charge density by introducing a positively or negatively charged material through the surface modification process of a thin film produced by electrostatic It relates to an air filter material with improved filtration performance and a method for manufacturing the same.

Description

Air mask filter and manufacturing method thereof {Air mask filter and manufacturing process of the same}

The present invention relates to an air filter for purifying air by removing particulate matter such as fine dust in the air.

By chemically modifying the surface of the thin film, it comes into contact with moisture.

It can also maintain the given electrostatic function, that is, it can be washed with water and the filtration performance is poor.

It relates to an improved air filter and a method for manufacturing the same.

With the development of industry, air pollution in residential areas as well as industrial zones is becoming increasingly serious due to urban concentration and the rapid spread of automobiles. is sulfur The reality is that these fine dust and air pollution greatly increase the frequency of respiratory and skin-related diseases such as colds, bronchitis, and atopic dermatitis.

Accordingly, various air purifiers to purify the air are rapidly spreading not only in large buildings and industrial sites, but also in general homes, and various types of masks are being provided to prevent inhalation of fine dust when going out.

The air purifier or mask as described above must necessarily include an air filter to filter out fine dust. Conventional air filters are simply manufactured to have fine pores so that air can pass through, but dust larger than a certain size cannot pass through. It is generally configured so that the filtration performance is determined according to the pore size.

Therefore, the smaller the pore size of the air filter is, the more fine dust can be filtered out. has a disadvantage.

In addition, when the pores of the air filter become smaller, the filtration performance of filtering out dust increases, but the air permeability is lowered, which leads to a problem of poor usability. For example, when a mask is made with an air filter with very small pores, it becomes very difficult for a user who wears the mask to breathe, so it has a disadvantage that it is impossible to wear the mask for a long time.

An electrostatic air filter that attracts and filters fine dust using static electricity to solve the above problems, that is, to increase the filtration performance while maintaining the size of the pores above a certain size (Republic of Korea Patent No. 10-0310274) has been proposed Since conventional air filters have pores of 20 to 30 µm, it is impossible to remove fine dust, so when using such a conventional air filter, not only dust flows out at the beginning of operation, but also dust remains on the filter surface after exhaustion. phenomenon occurs frequently. The electrostatic air filter is configured so that static electricity is generated in the fibers when the filter fiber is manufactured, so that even fine dust smaller than the pores of the fiber fabric is attached and filtered by static electricity, that is, even if the pores are not very small, it filters fine dust. There are advantages to being able to afford it.

However, in order to manufacture the conventional electrostatic air filter as described above, a process of depositing a polymer resin for a nonwoven fabric and a process of discharging under corona discharge are essential. The manufacturing process is very complicated, so productivity is very low and manufacturing cost is high. There is a disadvantage that there is a limit to commercialization.

In order to solve the above problems, that is, in order to improve the filtration performance while maintaining the size of the pores above a certain size, a material having an adhesive property instead of static electricity is sprayed onto the air filter fabric and becomes gelation when curing is completed. An air filter (Korean Patent Registration No. 10-1808115) in which fine dust in the incoming air is removed by adsorbing it to an adhesive gel has been proposed. Although the above-mentioned adhesive air filter can remove fine dust by an operating principle different from static electricity, the manufacturing process can be complicated and there is a sense of distance from consumer demand for a mask that can be washed and reused.

On the other hand, a mask air filter (Korean Patent Registration No. 10-1923106) has been proposed that improves the problems of the existing mask air purification filter, installs a washed filter, and applies static electricity from both ends using piezoelectric elements. As for the replaceable air filter, a simple piezoelectric element device is combined with the mask to provide a new electrostatic function from time to time, so it is possible to continuously manage the air purification ability. It has the characteristic of being able to continuously supply air.

However, in order to manufacture a mask with an air filter as described above, many attachments are required, the manufacturing process such as power connection is very complicated, productivity is very low, and the manufacturing cost increases as the number of attachments increases. It is inevitably difficult to supply in large quantities at an affordable price.

Republic of Korea Patent Publication 10-1923106 Republic of Korea Patent Publication No. 10-0310274 Republic of Korea Patent Publication 10-1808115

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An object of the present invention is to improve the disadvantages of the prior art, that is, the weakening of the electrostatic function given to the existing air filter material manufactured based on woven or non-woven fabric and the problem of direct static loss due to moisture, economical efficiency and control of filtration characteristics. A porous film made of an improved natural material is manufactured and a positively or negatively charged material is chemically applied to the surface of the surface, so that it can be washed with water and can efficiently remove fine dust particles. To provide a filter material.

An air filter manufacturing method according to the present invention for achieving the above object,

providing a filter fabric having pores;

chemically bonding an electrically charged material to the surface of the filter fabric;

superimposing the prepared positively charged porous thin film and negatively charged porous thin film, respectively, and using them as a set for the purpose of air purification based on electrostatic force; includes

The air filter according to the present invention comprises:

Filter fabrics manufactured through natural material blending and processing processes;

creating voids using an enzyme with respect to the prepared filter fabric;

including,

Filter fabrics made of materials containing natural polymers are manufactured through crosslinking for durability and structural reinforcement.

A proteolytic enzyme can be used to create pores in the filter fabric, and the pore size of the final filter fabric can be selectively controlled according to the purpose through the difference in the content ratio between polysaccharide and protein according to the raw material mixing ratio of natural materials. It is possible and can be easily manufactured.

The air filter according to the present invention has advantages in that it can effectively filter fine dust or ultra-fine particles while ensuring the size of the pores or more, and that the manufacturing process is relatively simple, thereby improving productivity and reducing manufacturing costs. In addition, using the air filter manufacturing method according to the present invention, it is relatively easy to control the pore size of the air filter, and it is possible to manufacture an air filter with excellent filtration performance due to the surface modification of the porous film, and it is possible to improve the productivity of the air filter and reduce the manufacturing cost. It has the advantage of being able to do it.

1 is a process diagram illustrating an air filter manufacturing process according to the present invention.
2 is a vertical cross-sectional schematic view of an air filter coated with a positive charge according to the present invention.
3 is a view of the multilayer porous thin film of the air filter according to the present invention.

Hereinafter, an air filter and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a process diagram schematically illustrating an air filter manufacturing process according to the present invention, FIG. 2 is a vertical cross-sectional view of the air filter according to the present invention, and FIG. 3 is a view of a thin film air filter having pores.

The air filter according to the present invention is a kind of air filter for efficiently filtering fine dust or ultra-fine particles in the air. Compared to the function to be manufactured, it is relatively simple and has a constitutional feature that is easily manufactured.

That is, the air filter according to the present invention is a natural polymer polysaccharide material, a protein material, and an organic acid that plays a role as a crosslinking agent between them in a certain ratio, mixed and homogenized, then dispensed into an appropriate container and dried under heating to crosslink (crosslink). ) to produce a finished thin film.

A natural material used as a raw material in this embodiment for manufacturing a thin film for an air filter is chitosan, and collagen, gelatin, etc. may be used as a protein raw material. As a natural material that can be used for manufacturing the air filter of the present invention, in addition to chitosan, natural polysaccharides such as cellulose, starch, and alginic acid may be used. On the other hand, as the crosslinking agent, carboxylic acid is used in the embodiment of the present invention, but in principle, a compound that forms a crosslink by other crosslinking reaction mechanisms can also be used. The final raw material solution is prepared through appropriate dissolution and blending of these components.

The chitosan material having a molecular weight of 100,000 to 300,000 is put into 1% acetic acid or formic acid at 50 degrees to become a final 2% chitosan solution, and dissolved by stirring for about 1 hour. Meanwhile, in a separate container, prepare a final 2% protein solution through the same process for the gelatin raw material.

Each of the raw material solutions is mixed in a 1:1 weight ratio, and the temperature of the mixed solution is maintained at 50°C and homogenized through stirring. In this stirring process, an organic acid serving as a crosslinking agent is appropriately added within a concentration range of 1-10 mM and mixed. In this embodiment, citric acid is used as an organic acid serving as a crosslinking agent. The final blending solution is prepared by stirring the blended solution to which citric acid is added at 50°C for an additional 1 hour.

If necessary to lower the temperature of the solution in which all the raw materials are mixed to 40 degrees and secure the flexibility of the thin film, 0.05% glycerin can be added in this step.

An appropriate amount of the mixture is dispensed into a glass container pre-heated at 40 degrees. Since the thickness of the final dried thin film may vary depending on the dispensing capacity, it is possible to control the thickness of the final thin film to be manufactured by determining and executing the dispensing capacity per container through this method.

The dispensed mixed solution is left to stand in an environment of 40 degrees for 24 hours to proceed with drying. If necessary, the exposure can be controlled within the range of 40 to 70 degrees for the drying process temperature to shorten the drying time.

As drying proceeds at the above temperature, a crosslinking reaction mediated by organic acid proceeds, and the final dried thin film is a thin film in the form of a flat plate in which pores are not formed. The crosslinking reaction of natural materials strengthens the durability of the air filter and at the same time provides insolubility when exposed to water.

The air filter according to the present invention purifies the air by the difference in the physical pore size of the fine dust flowing through the pores of the thin film. Therefore, the prepared thin film is treated with a proteolytic enzyme to induce pore formation.

Industrially useful enzymes such as trypsin, papain and bromelain may be used as the proteolytic enzyme input for preparing the porous film. Also, it is possible to use a pronase proteolytic enzyme produced by a microorganism (Streptomyces griseus).

The concentration of each enzyme used is appropriate at 1-5%, and the dried film is put into the enzyme reaction solution prepared in advance, and the solution is circulated for an appropriate time to decompose and remove the protein component constituting the thin film.

When the reaction is completed, the film is moved to another container, the remaining enzyme activity is stopped, and the film having a porous structure is recovered by additional washing, etc., and then dried at room temperature. The pores of the thin film prepared by using the proteolytic enzyme have non-linear characteristics, and the thicker the thin film, the more it has a multi-layered non-linear pore structure.

As shown in the vertical cross-sectional view of FIG. 2 , the air filter according to the embodiment of the present invention may have a physical pore size in the range of 10 to 15 μm and has a multi-layered pore structure. It is possible to variably control the size of the pores finally created through the change in the composition ratio of the polysaccharide and protein input in the step of preparing the raw material mixture solution. In the weight mixing ratio of chitosan and gelatin in this example, 100% by weight of gelatin was added relative to the weight of chitosan. For example, it can be prepared by adding 50 weight or 150 weight of protein relative to 100 weight of chitosan to be added for compounding.

In particular, in the pores of the film according to the present invention, the passage time of the contaminated fine particles is somewhat extended as air passes through the zigzag path inside the film rather than a linear void passing through the front and rear parts of the thin film. This gives the effect of increasing the chance of adsorption and removal of fine dust.

Fine dust or physical particles larger than the pores of the air filter according to the present invention do not easily pass through the zigzag pores, and in particular, in the case of droplets larger than the particle diameter of 5-10 μm, it is difficult to directly pass through the pores. Such large particles can be easily removed by using the outer fabric, that is, spunbond nonwoven fabric, used in conventional air purification masks, etc. in the first half of the air filter. Droplet nuclei or aerosol grades with fine particles smaller than 5 μm in diameter refer to particles in which solid or liquid fine particles are suspended in gas like smoke, and the size is about 100 nm to 5 μm.

In order to effectively remove fine particles smaller than the pore size, the air filter according to the present invention undergoes a surface modification process through an additional process for the porous thin film. Semi-permanent blackout function can be given.

In order to impart static electricity to the inside of the pores of the film according to the present invention, a material having a positive charge or a material having a negative charge can be separately provided. That is, the surface modification reaction can be initiated by immersing the porous thin film filter in a previously prepared alkali solution. The alkali solution of the present invention may be a caustic soda solution in a concentration range of 1 to 100 mM, and the concentration of caustic soda used can be variably adjusted and changed according to the desired degree of surface modification. The surface modification reaction proceeds while circulating the solution at room temperature or an appropriate temperature.

More specifically, when preparing the alkali solution to bind the positively charged material to the inner surface of the pores of the film according to the present invention, as a molar ratio, a positive charge equivalent to about twice the concentration of sodium hydroxide compound can be added. For example, in the case of a 50mM aqueous solution of caustic soda, it is prepared to have a concentration of 100mM, which is twice the concentration of the positively charged compound, and used.

When a positively charged material is applied to the porous thin film filter, the positively charged material used can be chloro diethylaminoethyl. Removal is made possible by this electrostatic force.

As another material of choice for positive charge coating purposes, 3-chloro-2-hydroxypropyltrimethylammonium chloride may be used. These are listed by way of example only, and other compounds having similar functions and purposes may be used.

A negatively charged compound can be imparted to the new porous thin film in a manufacturing method similar to the above, and sodium chloroacetate can be used as the negatively charged compound, and the surface modification process is performed in the same manner as above. This makes it possible to collect and remove positively charged surface particles or fine dust contained in the flowing air by electrostatic force when passing through the pores of the negatively charged porous thin-film filter that has been bonded.

The surface modification reaction proceeds for about 1 hour at room temperature, and the reaction parameters such as the applied reaction temperature and the concentration of the compound to be added can be variably adjusted according to the purpose such as adjustment of the charge density applied and shortening of the reaction time. When the surface modification reaction is completed, the air filter is moved to another container and the reaction process is completed by neutralization and washing with water.

As described above, by using the air filter manufacturing method according to the present invention, fine dust due to the difference in pore size and fine dust particles smaller than the pore size can be removed by semi-permanently added electrostatic force to the surface, and air with excellent filtration performance compared to the price Filters can be manufactured.

When the positively charged filter and the negatively charged filter according to the present invention are sequentially arranged and used, an air purification effect can be expected in a principle similar to the method of collecting and removing fine dust using the electrostatic principle.

The air filter produced in this way can be used industrially as a filter such as an air filter or air purification device. Since it is an electrostatic function obtained, the air purification function is continuously secured, and there is an advantage of maintaining the electrostatic force even in a moisture environment. In particular, the adsorbed fine dust can be easily removed by washing with water after use, so it can be reused and has a high cost-effectiveness.

As mentioned above, although the present invention has been described in detail using preferred embodiments, the scope of the present invention is not limited to specific embodiments and should be construed according to the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

The air filter according to the present invention can maintain the electrostatic function not only in air but also in a high humidity environment, so it fundamentally solves the problem of loss of electrostatic function due to moisture, which is the biggest disadvantage of the air purifying filter or mask equipped with the existing MB (melt-blown) filter. It can be overcome, so it can be used industrially as an alternative to the existing MB filter.

Since the filter fabric is manufactured by selecting an environmentally friendly material that is harmless to the human body, it can be used as a product in direct contact with the user's skin, such as a mask or a bandage.

In particular, the air purification filter according to the present invention can be reused after washing and can maintain the electrostatic function for a long time even in a high humidity environment, thereby reducing the economic burden of the user when applied to a mask.

210: a contaminant having a negative surface charge
220: average pore size of the porous thin film (10-15um)
230: positively charged surface modified thin film

Claims (5)

a filter made of a natural material that filters out foreign substances in the incoming air;
forming cross-links between natural materials so that the filter has structural durability;
treating the filter with a proteolytic enzyme so that the filter has pores greater than or equal to a reference value; and
chemically modifying the filter surface by binding a positively or negatively charged material to impart a charge density to the surface of the thin film having pores so that the filter is equipped with static electricity; including,
The filter is
As the foreign material is removed through washing and can be reused,
Filter fabric manufactured by mixing natural polysaccharides, proteins, and organic acids, which are crosslinking agents, in a certain ratio;
A filter manufactured by decomposing a specific raw material component among raw materials formulated for the manufacture of a porous filter;
It is manufactured by chemically combining to impart positive or negative charge density to the porous filter to have static electricity,
The natural polysaccharide is chitosan,
The protein is collagen or gelatin,
The crosslinking agent is an organic acid that is any one of carboxylic acids,
The proteolytic enzyme is any one of trypsin, papain, bromelain, pronase,
The air filter is an air filter characterized in that it removes foreign substances by using a thin film coated with positive charges coupled to a thin film having pores and a thin film coated with negative charges coupled to each other as a set.
According to claim 1,
Air filter, characterized in that in the step of preparing the raw material of the filter, the mixing ratio of polysaccharide and protein is prepared by mixing in a range of 50 to 150% based on the weight of polysaccharide.
According to claim 1,
The carboxylic acid used as the crosslinking agent of the filter is an air filter, characterized in that it uses an organic acid compound having at least two or more carboxyl groups.
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