KR20090103351A - An air filter comprising electrostatic filtering layer(s) consisting of spunlace non-woven fabric produced from polyolefin short fibers - Google Patents

Abstract

PURPOSE: An air filter including a static filter layer consisting of spun lace non-woven manufactured of polyolefin monofiber is provided to offer superior dust collecting efficiency for a long time. CONSTITUTION: Spun lace non-woven for a static filter layer includes monofiber. The polyolefin monofiber includes 80~100 weight% of the monofiber. The monofiber includes natural, synthetic or reproduction monofiber of 0~20 weight%. The spun lace non-woven is manufactured by spun lacing. The air filter includes a static filter layer consisting of the spun lace non-woven.

Description

An air filter comprising an electrostatic filter layer consisting of a spunlace nonwoven fabric made of polyolefin short fibers {AN AIR FILTER COMPRISING ELECTROSTATIC FILTERING LAYER (S) CONSISTING OF SPUNLACE NON-WOVEN FABRIC PRODUCED FROM POLYOLEFIN SHORT FIBERS}

The present invention relates to a polyolefin short fiber for an air filter, a spunlace nonwoven fabric for an electrostatic filter layer including the polyolefin short fiber, a method for manufacturing the same, and an air filter including an electrostatic filter layer composed of the spunlace nonwoven fabric.

Types of air filters include pre-filters such as automobile cabin filters, bag filters, air conditioning filters, air clean filters, neutral performance filters, hepa filters, ulpa filters, and the like. Hepa filters ) Is composed of a support layer, a filtering layer, and a covering layer, and an electrostatic air filter is composed of a prefilter layer, an ultrafine fiber layer, and a carrier layer and a support layer.

On the other hand, filtration mechanisms of particles include diffusion, inertia, gravity, interception, electrostatics, and the like. Filtration of particles by diffusion is a trapping effect on the fibers because relatively small particles in Brownian motion, regardless of the flow of air, have a long and directional movement between the fibers of the filter; Filtration of particles by inertia is a trapping effect in which particles approaching the fiber by the flow of a fluid escape from the airflow by their inertia and impinge on the fibers of the filter; The filtration of particles by gravity is a trapping effect in which particles approaching the fiber by the flow of air settle out of the flow due to their gravity and settle on the fibers of the filter; Filtration of particles by blocking is a trapping effect on the fibers of the filter by the size of the particles even when the particles are moving in the flow of the fluid; Filtration of particles by static electricity causes particles charged with + or-in the particles suspended in the air to be electrostatically trapped in the fibers of the filter having permanent electric polarization and forming an electric field (electric field) around them. Particles in which the particles are not neutrally charged also have an induced charge generated by the electrostatic filter fibers and are collected on the fibers.

The electrostatic filter layer used in the conventional air filter is a polyolefin-based melt blown nonwoven fabric or a polyolefin or polyester spunbond nonwoven fabric made of microfiber, and water using corona discharge, plasma charging, and charged water droplets. Electrostatic treatment such as electrification has become mainstream.

However, polyolefin-based melt blown nonwoven fabrics have good trapping efficiency by spinning with a microfiber, but have high pressure loss, resulting in poor air permeability. Therefore, they are suitable for the manufacture of HEPA filters such as air cleaners, which require relatively high efficiency and low air permeability. There is a limitation in applying to a cabin filter, a bag filter, an air conditioning filter, and various neutral performance filters which are required. Polyolefin or polyester spunbond nonwoven fabrics also tend to have low collection efficiency when designed for products that require high air permeability, and have poor air permeability when designing high collection efficiency. Recently, nonwoven fabrics produced by nanospinning may satisfy high air permeability and high collection efficiency at the same time, but the commercialization of the technology is still insufficient, and even if commercialized, it is too early to be applied to a neutral performance filter.

Therefore, in various air filter fields, there is an urgent need for the development of an electrostatic filter layer having low pressure loss and high air permeability, excellent collection efficiency and long collection performance. Best of all, low pressure loss at low weight and high collection efficiency can be economical electrostatic filter layers.

The present invention provides a variety of air filters (especially neutral air filters) including an electrostatic filter layer comprising polyolefin-based short fibers, which have a low pressure loss and a high air permeability, and have a very good collection efficiency (performance). It is intended to make it commercially available, and to be widely used in various cleaning tools (eg, mops, electrostatic wipers, etc.) and dust collecting masks using static electricity.

The present invention relates to a polyolefin resin selected from the group consisting of (i) polyolefin homopolymers, random copolymers, block copolymers, and mixtures thereof, (ii) antistatic agents, or amines of monoglycerides, polyglycerides, or mixtures thereof. Antistatic agents of the system, (iii) an additive selected from the group consisting of calcium carbonate, calcium stearate and titanium dioxide, and (iv) a group consisting of rutile or anatase type titanium dioxide, barium titanate and calcium carbonate Including inorganic material of the high dielectric constant selected from, the surface of the fiber is treated with a spinning oil 0.1 to 2.0% by weight of the fiber for imparting friction and antistatic properties suitable for carding, the fineness is 0.5 to 6.0 denier Provided is a polyolefin short fiber for an air filter.

To improve the electrostatic performance of short polyolefin fibers, (v) fluorinated polymer selected from the group consisting of polyvinylidene fluoride (PVDF), chlorotrifluoroethylene (CTFE) and polytetrafluoroethylene (PTFE) is added. It may be included as.

The polyolefin resin may be a homopolymer or a random polymer or a block copolymer of polyolefins including polypropylene (PP), polyethylene (PE), etc., may be a mixture of polyolefins and polyolefins or polyolefin copolymers, and complex spinning of different polyolefins. It may be in one form. It is preferable that polyolefin is polypropylene (PP).

The antistatic agent may be a general-purpose low molecular antistatic agent (for example, monoglyceride-based, polyglyceride-based, or a mixed antistatic agent thereof) or a polymer antistatic agent (for example, an amine antistatic agent), and is a monoglyceride antistatic agent. It is preferred that it is glycerol monostearate (GMS). The content of the antistatic agent is preferably more than 0 wt% and 0.5 wt% or less (more than 0 ppm and 5,000 ppm or less).

Examples of the additive for the polyolefin polymer include calcium carbonate, calcium stearate, titanium dioxide, and the like, and may further include primary and secondary antioxidants.

High dielectric constant inorganic material selected from the group consisting of rutile type or anatase type titanium dioxide, barium titanate and calcium carbonate can be charged for a long time by electrostatic treatment such as charging due to friction in carding process, corona or plasma By maintaining it, it helps to maintain durable collection efficiency.

Fluorine-based polymers selected from the group consisting of polyvinylidene fluoride (PVDF), chlorotrifluoroethylene (CTFE) and polytetrafluoroethylene (PTFE) contribute to the electrostatic improvement when added during spinning.

The spinning oil used in the fiber surface treatment is preferably a fluorine-based, chlorine-based or silicone-based spinning oil, but may be hydrophilic, hydrophobic or permanent hydrophilic as long as proper carding properties are provided. This is because most of the spinning oil on the surface of the polyolefin short fibers is eliminated by the high-pressure water flow during the spunlace processing, and thus, it does not significantly affect the collection (dust collection) efficiency.

The fineness of the polyolefin short fibers for air filters of the present invention is 0.5 to 6.0 denier, preferably 1.0 to 3.0 denier. If the fineness is less than 0.5 denier, the collection (collecting) efficiency is good, but not only is difficult to manufacture the fiber, but also bad carding can lead to nonwoven fabric processing failure. In addition, when the fineness exceeds 6.0 denier, the air permeability is good, but the collection (dust collection) efficiency is lowered and may cause a spunlace nonwoven fabric defect.

It is preferable that the polyolefin short fiber for air filters of this invention is a release cross-sectional form. Since the polyolefin polymer is swelled due to viscoelasticity when discharged through the spinneret in the molten state, the polyolefin polymer may have a streamlined cross-sectional shape. The polyolefin short fibers for the air filter of the present invention have a streamlined vertex. It is preferable that at least three of the corner angles of the connection line directed toward the inside of the fiber when connecting the vertices in the circumferential direction by expressing the point as a point are release cross-sectional polyolefin fibers not exceeding 90 degrees.

The polyolefin short fibers for air filters of the present invention are well suited for the production of spunlace nonwoven fabrics used for electrostatic filter layer applications of air filters since they exhibit good electrostatic treatment and high collection efficiency.

In addition, the present invention comprises (i) 80 to 100% by weight of the above-mentioned polyolefin short fibers for air filter, and (ii) 0 to 20% by weight of natural, synthetic or regenerated short fibers used for nonwoven fabrics, Spun lacing) to provide a spunlace nonwoven fabric for an electrostatic filter layer, which has a basis weight range of 10 to 150 gsm.

The short fibers of (ii) are polyethylene terephthalate (PET) fibers, nylon fibers, polyethylene terephthalate (PET) / polyethylene (PE) fibers, polyethylene terephthalate (PET) / polypropylene (PP) fibers, polypropylene (PP) ) / Polyethylene (PE) fibers, cellulose fibers, polyvinyl alcohol (PVA) fibers, fluorine-based polymer fibers, acrylic fibers and modacryl fibers may be one or more synthetic or regenerated short fibers selected from the group consisting of. .

Since the spunlace nonwoven fabric for an electrostatic filter layer of this invention is manufactured by water flow entanglement (spun lacing), it shows the outstanding collection performance and high air permeability compared with the nonwoven fabric manufactured by thermal bonding, needle punching, etc.

The spunlace nonwoven fabric for the electrostatic filter layer of the present invention preferably has a basis weight range of 10 to 150 gms, when less than 10 gms is not only difficult to machine, but also poor water flow caused mechanical degradation and performance degradation, 150 gms If exceeded, the air permeability is lowered.

In the spunlace nonwoven fabric for the electrostatic filter layer, fine holes are formed in a vertical stripe pattern in the machine direction MD. These holes are designed for the size and arrangement of jet holes in water jets, the spacing of jets, etc., shells (eg drum shells, conveyor shells, wire mesh shells, porous shells). , Pattern or embossing shell, etc.], water flow pattern recovery (water jet passage recovery) and the like, and accordingly, the air permeability of the spunlace nonwoven fabric for the electrostatic filter layer can be adjusted.

The spunlace nonwoven fabric for the electrostatic filter layer is preferably further electrostatically treated in the form of corona discharge, plasma charging, water charging using charged water droplets, or a combination thereof in order to improve collection efficiency (ie, collecting performance). Do.

In addition, the present invention provides a method for producing a spunlace nonwoven fabric for an electrostatic filter layer, comprising: (a) 80 to 100% by weight of the above-mentioned polyolefin short fibers for air filters, and (ii) natural and synthetic materials used for the nonwoven fabric described above. Or carding polyolefin-based short fibers including 0-20 wt% of regenerated short fibers; (b) spraying a polarized liquid, including purified water, onto the carded polyolefin-based short fiber web by a high pressure jet of water with a water jet; And (c) drying the nonwoven fabric produced by water flow (spun lacing) by air drying, thermal drying, mechanical drying, vacuum drying, or a combination thereof. Between step (a) and step (b), after the corona discharge treatment of the carded polyolefin-based short fibers may further comprise the step of wetting with a wetting liquid, including isopropanol (IPA). In addition, after the step (c), the nonwoven fabric may further include an electrostatic treatment step selected from the corona discharge, plasma charging, triboelectric charging, water charging through the charged water droplets.

The method not only provides high air permeability and low pressure loss (0.05 to 0.6 mmAq) by forming fine holes in the machine direction (MD) in the nonwoven fabric through water flow, but also imparts spinning for carding processability. Removes emulsions (spinning agents adhere to polyolefin short fibers, which impedes electrostatic and dust collection performance), resulting in better electrostatic treatment in post-processing, improved collection efficiency and durability, and high-pressure injection of polar liquids, including purified water As a result of the collision with the carded web or nonwoven fabric, electric charges are generated to double the electrostatic property of the web or nonwoven fabric, thereby enabling the permanent or semi-permanent collection (dust collection) efficiency to be maintained.

In step (a), the polyolefin-based short fibers have a (-) charge and the chargeability is increased by the frictional force during carding.

The polyolefin-based short fiber web carded in step (b) generates charges by collision with high pressure water stream. Step (b) may be repeated at least twice, preferably at least four times (eg, at least two times in front, at least two times in back) at a pressure of 40 bar or more.

Step (c) is preferably performed for 30 seconds or more at a temperature of 100 or more.

The electrostatic treatment (especially corona discharge treatment) between the step (b) and the step (c) and the wet treatment using the wetting liquid (eg isopropanol, etc.) are optionally carried out to further improve the collection (dust collection) efficiency. Can be.

After step (c), electrostatic treatment (corona discharge, plasma charging, etc.) may be selectively added to improve collection (dust collection) efficiency.

In addition, the present invention provides an air filter comprising the electrostatic filter layer composed of the aforementioned spunlace nonwoven fabric for the electrostatic filter layer. The air filter may further include an adsorption / deodorization layer selected from the group consisting of activated carbon fibers, carbon nanotubes (CNTs), zeolites, silica gels, activated aluminas, ion exchange resins, and ion exchange fibers.

In the air filter of the present invention, the spunlace nonwoven fabric for the electrostatic filter layer is, for example, spunbond (SB) nonwoven fabric, melt blown (MB) nonwoven fabric, nano spinning nonwoven fabric, needle punch (NP) nonwoven fabric, thermal bond (TB) nonwoven fabric, It can be laminated with one or more of airlaid (AL) nonwoven fabric, wet nonwoven fabric or paper filter to form a composite layer of two to four layers, and the interlayer bonding of the composite layers is ultrasonic bonding, thermal bonding, hot melt bonding, and needle punching. It is preferable that it consists of bonding using water flow, stitch bonding, and an adhesive agent.

The single layer air filter collects dust particles contained in the air in the surface layer composed of the aforementioned spunlace nonwoven fabric for the electrostatic filter layer.

The two-layer air filter consists of a surface layer and a support layer. The surface layer consisting of the spunlace nonwoven fabric for the electrostatic filter layer described above collects dust particles contained in the air, and the support layer firmly supports the upper surface layer and maintains strength. It is mainly responsible for collecting dust and also collecting dust. On the other hand, in order to increase the contact area with the air can be folded in the shape of a fan, in this case by using a firm support layer also improves the foldability.

The three-layer air filter includes a surface layer composed of a spunbond nonwoven fabric of various materials, a needle punch nonwoven fabric, and the like, which preferentially collects large dust particles contained in the air; An intermediate layer composed of the aforementioned spunlace nonwoven fabric for the electrostatic filter layer to collect fine dust particles; And a support layer that serves to firmly support the upper surface layer and the intermediate layer, maintains strength, and partially collects dust. On the other hand, in order to increase the contact area with air can be folded in the shape of a fan, in this case, by using a firm support layer also improves the foldability.

On the other hand, when the high performance filter is to be prepared, the aforementioned spunlace nonwoven fabric for the electrostatic filter layer may be disposed on the surface layer, and the meltblown nonwoven fabric or the nanospun nonwoven fabric may be disposed on the intermediate layer.

The four-layer air filter includes a surface layer composed of a spunbond nonwoven fabric of various materials, a needle punch nonwoven fabric, and the like, which preferentially collects large dust particles contained in the air; An electrostatic fiber layer composed of the aforementioned spunlace nonwoven fabric for the electrostatic filter layer to collect fine dust particles; It is composed of activated carbon fiber, carbon nanotube (CNT), zeolite, silica gel, activated alumina, ion exchange resin, ion exchange fiber, and it is selected from the group consisting of functionality that gives functions such as adsorption, deodorization, harmful gas removal and antibacterial. Grant layer; And a support layer which mainly serves to firmly support the upper surface layer, the electrostatic fiber layer, and the functional imparting layer, maintain strength, and partially collect dust. The positions of the functional imparting layer and the electrostatic fiber layer can be reversed. On the other hand, in order to increase the contact area with the air can be folded in the shape of a fan, in this case by using a firm support layer also improves the foldability.

On the other hand, when the high performance filter is to be prepared, the aforementioned spunlace nonwoven fabric for the electrostatic filter layer may be disposed on the surface layer, and the meltblown nonwoven fabric or the nanospun nonwoven fabric may be disposed on the electrostatic fiber layer.

Since the air filter of the present invention includes an electrostatic filter layer having excellent collection efficiency and high air permeability characteristics, pre-filters such as automobile cabin filters, bag filters, air conditioning filters, air cleaning filters, neutral performance filters, hepa filters, etc. It can be widely used for ulpa filter.

According to the present invention, a variety of air filters (especially neutral air), including an electrostatic filter layer comprising polyolefin-based short fibers, which have a low pressure loss and a high air permeability, and have a very good collection efficiency (performance). Filter) can be commercialized, and can be widely used for various cleaning tools (eg, mops, electrostatic wipers, etc.) and dust collecting masks using static electricity.

1 is an electron micrograph of a polyolefin short fiber for an air filter according to the present invention.

Figure 2 is an electron micrograph of the polyolefin short fibers for air filter of the cross-sectional shape according to the present invention.

3 is a photograph showing a spunlace nonwoven fabric for an electrostatic filter layer of the present invention in which fine holes are formed in a vertical stripe pattern in the machine direction (MD) according to the present invention.

Figure 4 shows the air filter of the single layer, two layers, three layers and four layers structure according to the present invention, respectively.

Figure 5 shows the manufacturing process of the spunlace nonwoven fabric for an electrostatic filter layer according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: surface layer

20: middle layer

21: electrostatic fiber layer (or functional imparting layer)

22: functional imparting layer (or electrostatic fiber layer)

30: support layer

Through the following examples will be described in more detail the present invention. However, the following examples are only for illustrating the present invention, and the scope of the present invention should not be construed as being limited to the following examples. Therefore, it will be understood by those skilled in the art that various modifications, changes, and applications are possible within the scope of the technical idea derived from the matters described in the appended claims.

Example

Example  One

(i) a polypropylene (PP) resin having a melt index of 12 g / 10 min, (ii) 500 ppm of glycerol monostearate (GMS) as an antistatic agent, (iii) 500 ppm of calcium stearate, and (iv) 1000 ppm of rutile titanium dioxide And a polypropylene short fiber having a circular cross-section having a surface of 0.4 wt% and treated with a hydrophilic spinning oil, having a fineness of 1.5 denier and a length of 40 mm. The short polypropylene fibers were then carded. Subsequently, the carded polypropylene-based short fiber web was sprayed with a high pressure jet of a polar liquid, including purified water, with a water jet to spun the water flow. The water flow passed through the waterjet four times to the front-back-front-bag with water pressure of 15-80-80-80 bar. Subsequently, the nonwoven fabric produced by water flow (spun lacing) was dried at a temperature of 100 or more for 30 seconds or more. The dried nonwovens were treated with corona discharge (28 kV, 0.2 mA, passing through five corona treatment bars (+3, -2)). The basis weight of the spunlace nonwoven fabric produced was 40 gms. The spunlace nonwoven fabric thus produced is a single layer air filter including an electrostatic filter layer (prefilter layer), and a polyethylene terephthalate (PET) spunbond nonwoven fabric (support layer) having a basis weight of 72 gms with the electrostatic filter layer (prefilter layer). Pressure loss and collection efficiency of the air filters of the laminated composite layers were evaluated according to the NaCl aerosol test method (measurement device: TSI 8130, flow rate: 32 l / min).

The pressure loss of the spunbond nonwoven fabric support layer, the collection efficiency before the corona discharge treatment, and the collection efficiency after the corona discharge treatment are shown in Table 1 below.

Before corona discharge treatment After Corona Discharge Treatment Pressure loss (mmAq) Collection efficiency (%) Collection efficiency (%) day day 15 days later 0.20 8.10 27.4 9.5

Example  2

It is the same as Example 1 except that the polypropylene short fiber surface-treated with Si type hydrophobic spinning oil was used.

Example  3

It is the same as Example 1 except that the polypropylene short fiber surface-treated with the common spunlace spinning oil was used.

Example  4

It is the same as Example 1 except that the polypropylene short fiber of the Y-type cross-section surface-treated with the spunlace spinning oil for general use was used.

Example  5

It is the same as Example 1 except the polypropylene short fiber of the + type cross section surface-treated with the common spunlace spinning oil.

Example  6

It is the same as Example 1 except the polypropylene short fiber which surface-treated with the general spinning oil for spunlace, and the content of the antistatic agent glycerol monostearate (GMS) of 5,000 ppm was used.

Example  7

It is the same as Example 1 except the polypropylene short fiber which surface-treated with the general spinning spun lace oil agent, and whose fineness was 6.0 denier was used.

Example  8

Except for surface treatment with a spunlace spinning oil for general use, carding was performed by uniformly blending 20% by weight of a general-purpose polyethylene terephthalate (PET) short fiber having a fineness of 1.5 denier and a length of 40 mm. Is the same as

Example  9

It is the same as Example 1 except the polypropylene short fiber surface-treated with the common spunlace spinning oil, and 1000 ppm of anatase type titanium dioxide was used.

Comparative example  One

Same as Example 1, except that the polypropylene short fibers treated with Si-based hydrophobic spinning oil were used and the carded polypropylene short fibers were web bonded by needle punching.

Comparative example  2

Same as Example 1 except that the carded polypropylene short fibers were web bonded by thermal calender bonding.

Comparative example  3

Same as Example 1 except that the polypropylene short fibers treated with Si-based hydrophobic spinning agent were used and the carded polypropylene short fibers were web bonded by thermal calender bonding.

Comparative example  4

A polypropylene resin having a melt index of 1,100 g / 10 min was used to form a web in a meltblown manner with a fiber diameter of 1.5, web bonding by thermal calender bonding, and no surface treatment with a spinning oil. And the same as in Example 1.

Comparative example  5

Same as Example 1 except that the web was formed by spunbond using a polypropylene resin having a melt index of 34 g / 10 min, the web was bonded by thermal calender bonding, and was not surface treated with a spinning oil. .

Comparative example  6

It is the same as Example 1 except that the polypropylene short fiber surface-treated with the general purpose spunlace spinning oil and the content of the antistatic agent glycerol monostearate (GMS) of 10,000 ppm was used.

Comparative example  7

It is the same as Example 1 except the polypropylene short fiber which is surface-treated with the common spunlace spinning oil and whose fineness is 8.0 denier was used.

Comparative example  8

Example 1, except that the surface treated with a universal spunlace spinning oil, and carded by uniformly blending 30% by weight of general-purpose polyethylene terephthalate (PET) short fibers having a fineness of 1.5 denier and a length of 40 mm. Is the same as

Comparative example  9

It is the same as Example 1 except that it was surface-treated with the common spunlace spinning oil, and titanium dioxide was not added.

The results of Examples 1-9 and Comparative Examples 1-9 are shown in Table 2 below.

As can be seen from Table 2, the air filter including the electrostatic filter layer consisting of a spunlace nonwoven fabric made of polyolefin short fibers of the present invention exhibits low pressure loss and high air permeability and excellent collection (dust collection) performance.

Claims (19)

(i) a polyolefin resin selected from the group consisting of polyolefin homopolymers, random copolymers, block copolymers, and mixtures thereof; Inhibitor, (iii) an additive selected from the group consisting of calcium carbonate, calcium stearate and titanium dioxide, and (iv) a rutile or anatase type titanium dioxide, barium titanate and calcium carbonate Contains minerals of high dielectric constant, 0.1 ~ 2.0 wt% of surface is treated with spinning oil. Polyolefin short fibers for air filters, characterized in that the fineness is 0.5 ~ 6.0 denier. The method of claim 1, In order to improve the electrostatic performance of the short polyolefin fibers (v) fluorinated polymer selected from the group consisting of polyvinylidene fluoride (PVDF), chlorotrifluoroethylene (CTFE) and polytetrafluoroethylene (PTFE) Polyolefin short fibers for an air filter, characterized in that it further comprises. The method of claim 1, Polyolefin short fibers for air filters, characterized in that the cross-sectional shape. The method of claim 3, wherein When the streamlined vertices are displayed as points, at least three of the corner angles of the connection lines facing the inside of the fiber do not exceed 90 degrees when connecting the vertices in the circumferential direction of the cross section. Short fibers. The method according to any one of claims 1 to 4, The content of the antistatic agent is polyolefin short fibers for air filters, characterized in that more than 0% by weight and 5% by weight or less. The method according to any one of claims 1 to 4, The polyolefin is a polyolefin short fiber for an air filter, characterized in that the polypropylene (PP). The method according to any one of claims 1 to 4, The fineness of the polyolefin short fibers for air filter is polyolefin short fibers for air filter, characterized in that 1.5 ~ 3 denier. (i) 80 to 100% by weight polyolefin short fibers for air filters, and (ii) 0 to 20% by weight natural, synthetic or regenerated short fibers used for nonwoven applications, A spunlace nonwoven fabric for electrostatic filter layers, which is produced by water flow (spun lacing) and has a basis weight range of 10 to 150 gsm. The method of claim 8, The spunlace nonwoven fabric for the electrostatic filter layer is a spunlace nonwoven fabric for the electrostatic filter layer, characterized in that the fine holes in the machine direction (MD) is formed in a vertical stripe pattern. The method of claim 8, The spunlace nonwoven fabric for the electrostatic filter layer is a spunlace nonwoven fabric for an electrostatic filter layer, characterized in that the additional electrostatic treatment in the form of a corona discharge, plasma charging, water charging using a charged drop or a combination thereof. The method of claim 8, The short fibers of (ii) are polyethylene terephthalate (PET) fiber, nylon fiber, polyethylene terephthalate (PET) / polyethylene (PE) fiber, polyethylene terephthalate (PET) / polypropylene (PP) fiber, polypropylene (PP) ) / Polyethylene (PE) fibers, cellulose fibers, polyvinyl alcohol (PVA) fibers, fluorine-based polymer fibers, acrylic fibers and modacryl fibers selected from the group consisting of at least one synthetic or regenerated short fibers Spunlace nonwoven fabric for electrostatic filter layers. As a method for producing a spunlace nonwoven fabric for an electrostatic filter layer, Carding polyolefin short fibers comprising (a) 80 to 100% by weight of polyolefin short fibers for air filters, and (ii) 0 to 20% by weight of natural, synthetic or regenerated short fibers used for nonwovens. ); (b) spraying a polarized liquid, including purified water, onto the carded polyolefin-based short fiber web by a high pressure jet of water with a water jet; And (c) drying the nonwoven fabric produced by water flow (spun lacing) by air drying, thermal drying, mechanical drying, vacuum drying, or a combination thereof. The method of claim 12, And between step (a) and step (b), after the corona discharge treatment of the carded polyolefin-based short fibers, followed by wetting with a wetting liquid including isopropanol (IPA). The method according to claim 12 or 13, The step (b) is characterized in that it is repeated two or more times at a pressure of 40 bar or more. The method according to claim 12 or 13, Step (c) is performed for at least 30 seconds at a temperature of 100 or more. An air filter comprising an electrostatic filter layer composed of a spunlace nonwoven fabric for an electrostatic filter layer according to any one of claims 8 to 11. The method of claim 16, Air filter, characterized in that it further comprises an adsorption / deodorization layer selected from the group consisting of activated carbon fibers, carbon nanotubes (CNT), zeolites, silica gel, activated alumina, ion exchange resins, ion exchange fibers. The method of claim 16, The spunlace nonwoven fabric for the electrostatic filter layer is a spunbond (SB) nonwoven fabric, melt blown (MB) nonwoven fabric, nano spinning nonwoven fabric, needle punch (NP) nonwoven fabric, thermal bond (TB) nonwoven fabric, double side reflective film (AL) nonwoven fabric, wet type An air filter, characterized in that it is laminated with at least one of a nonwoven fabric or a paper filter to form a composite layer of two to four layers. The method of claim 18, Interlayer bonding of the composite layer is an air filter, characterized in that made by ultrasonic bonding, thermal bonding, hot melt bonding, needle punching, water flow, stitch bonding, bonding using an adhesive.