KR20160118169A - Filter media for protecting electronic device and filter assembly - Google Patents

Abstract

Provided is a filter medium which includes an organic polymeric nanofiber non-woven fabric, a melt-blown and span bond polypropylene non-woven fabric. Also provided is a filter assembly including the same. According to the present invention, the filter medium is produced by the following steps: forming an organic polymeric nanofiber non-woven fabric layer on a binary base material; forming a polyethylene terephthalate base material on the other side of the binary base material; and forming the melt-blown and span bond polypropylene non-woven fabric on one side of the organic polymeric nanofiber non-woven fabric layer. In addition, the filter assembly is then produced by installing the produced filter medium onto a filter frame.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a filter medium for protecting an electronic device,

The present invention relates to a filter medium for protecting an electronic device and a filter assembly comprising the same, and more particularly, to a filter assembly for protecting an electronic device by electrospinning an organic polymer solution on a two-component substrate and then using a polyethylene terephthalate (PET) An organic polymer nanofiber nonwoven fabric bonded to a meltblown and spunbonded polypropylene nonwoven fabric, and a filter assembly comprising the filter medium and the filter frame.

The present invention is based on the general problem that electronic components generate heat and the generated self heat must not exceed a temperature limit of 65 占 폚. This problem occurs especially in electronic components mounted in enclosed housings. The larger the ratio between the generated heat and the surface of the housing, the greater the problem of heat generation. This problem occurs especially in cupboards and base stations, which are well known in the field of communications. If the temperature exceeds 65 ° C, the base station is automatically shut off. For this reason, electronic devices such as, for example, heat exchangers, air conditioners, and fan-type cooling units must generally be cooled.

Of particular concern is cooling the housing in the event that the housing is installed externally or is substantially unprotected or exposed to ambient air. In such an environment, moisture-sensitive electronic components must be protected, particularly from the outside environment. It is necessary to protect the electronic parts mounted in the housing from moisture to some extent by preventing water or moisture from flowing into the inside of the housing. In addition, the housing itself must be sufficiently resistant to external temperature changes. This is particularly effective when the housing is installed in a place where, for example, a fire can occur. The basic environmental conditions under which the above-mentioned base station can withstand are described in European Telecommunications Standard ETS 300 019-1-4 (February 1992 edition).

With respect to the waterproofness of the housing, manufacturers must produce a housing with an IP rating of 55 (DIN 40 050). The second figure here means that even if a jet is applied to the housing in each direction, the housing is not affected.

There are currently two solutions to solve this problem. The first solution is to cool the housing through a heat exchanger. Air-to-water heat exchangers are very expensive, and it is not only dangerous to use water, but also can be applied in a limited manner if defective connections are made. The heat exchangers used here are usually air-to-air heat exchangers. Although the air-to-air heat exchanger seals the housing completely from the external element, it can not lower the housing temperature to more than 10K above the external temperature. The air-to-air heat exchanger can only cool the internal temperature of the housing to 65 ° C in the temperature zone where the external temperature is 55 ° C, in which case the power of the apparatus is cut off as described above. Obviously, if the operating temperature is raised by 10 ° C, the lifetime of the semiconductor is halved based on the maximum allowable operating temperature. The air-to-air heat exchanger is therefore not suitable for cooling the housing.

Another solution is to cool the fan. In this case, the housing is provided with an air inlet and an air outlet, as well as a fan that allows air to flow from the air inlet through the fan housing to the air outlet. The inflow of water is blocked by the waterproof cover, but the flow of air is not limited by the waterproof cover. In this case, however, the protection value is limited to IP 54. In the case of the waterproof cover, the waterproof cover is not completely watertight since an arbitrary section must be opened for smooth ventilation. For example, moisture can be introduced in droplet form or aerosol form. The advantage of this solution over air-to-air heat exchangers is that the temperature deviation between the external temperature and the housing internal temperature is significantly less than the temperature variation that can be reached with the air-to-air heat exchanger. The two cooling systems described above are commercially available from, for example, Ritalolf, Rudolf Loh GmbH & GB-A-2 147 663 describes a method for placing and cooling electronic components which must be protected from dust, oil or other particles on conventional cylindrical automotive filters wherein the air is in the zigzag form Of the corrugated porous filter element and is limitedly discharged through the tube.

DE-A-211 268, filed in 1972, describes a fan-type cooling unit for use in a device comprising a exothermic conductor plate. In the case of this fan-type cooling unit, air is introduced through a conventional filter, delivered through a housing containing a conductor plate, and discharged again from the housing. This device can not be installed externally. The problem that arises when using conventional filters is that it does not have sufficient protection for the jet stream. Another problem is that dust particles are transported to the fiber layer section of the filter and accumulate therein, so that the hole of the filter is easily sealed and the exchange period is shortened. Moreover, this kind of filter is not cleanable.

In automotive headlamps as described in DE-C-42 34 919, materials which pass steam or air but do not pass water are used to ensure a small amount of passive air exchange between the durability space of the headlight and the outside air It is known. This also serves to remove moisture that corrodes the headlight from the incoming air for pressure compensation when the headlight is re-cooled after use.

DE-A-197 55 944, which was filed prior to the date of the above-mentioned invention, but which was later published, describes a fan-type cooling unit in which a membrane filter is arranged in front of the air inlet. This patent also discloses the structural form of the membrane filter.

Korean Registered Patent No. 10-0606523 Korean Patent Registration No. 10-1293101 Korean Patent Publication No. 10-2012-0047228

Disclosure of the Invention The present invention has been conceived to solve the problems as described above. It is an object of the present invention to provide an organic polymer nanofiber nonwoven fabric having a two-component base material laminated on a polyethylene terephthalate base material and laminated by electrospinning on the two- The present invention provides a filter medium for protecting electronic devices and a filter assembly comprising the nonwoven fabric, the meltblown polypropylene nonwoven fabric laminated on the organic polymer nanofiber nonwoven fabric, and the spunbonded polypropylene nonwoven fabric. An object of the present invention is to provide a filter capable of reducing the pressure loss of the conventional filter, increasing the filtration efficiency, and extending the service life of the filter.

It is another object of the present invention to provide a filter medium and a filter assembly which can easily be desorbed even when the nanofiber nonwoven fabric is laminated by using the two-component base material.

According to a preferred embodiment of the present invention, there is provided a polyethylene terephthalate base material, a bicomponent base material laminated on the polyethylene terephthalate base material, an organic polymer nanofiber nonwoven fabric laminated on the binary material by electrospinning, There is provided a filter medium for protecting an electronic device comprising a meltblown polypropylene nonwoven fabric laminated on a nonwoven fabric and a spunbonded polypropylene nonwoven fabric laminated on the meltblown polypropylene nonwoven fabric.

According to another preferred embodiment of the present invention, the organic polymer is polyurethane or polyvinylidene fluoride.

According to another preferred embodiment of the present invention, the two-component substrate is a sheath-core type, a side by side type, or a C-type type.

According to another preferred embodiment of the present invention, the basis weight of the nanofiber nonwoven fabric is 0.1 to 2 g / m ² .

According to another preferred embodiment of the present invention, the basis weight of the binary material is 10 to 50 g / m ² , the basis weight of the meltblown polypropylene nonwoven fabric is 10 to 50 g / m ² , the basis weight of the polyethylene terephthalate base material is 50 to 150 g / m ² , and the basis weight of the spunbonded polypropylene nonwoven fabric is 20 to 80 g / m ² .

According to another preferred embodiment of the present invention, there is provided an electronic device protection filter assembly comprising the filter medium and a filter frame on which the filter medium is installed.

According to another preferred embodiment of the present invention, the filter assembly for protecting an electronic device is for communication, outdoor advertisement, or DID (Digital Information Display).

As described above, the filter of the present invention having the above-described structure can increase the filtration efficiency and extend the life of the filter as the nanofiber nonwoven fabric is laminated on the filter substrate.

Further, there is an effect that the separation between the nanofibers and the substrate is not likely to occur even without using an adhesive such as hot melt.

Hereinafter, a filter medium for protecting an electronic device of the present invention will be described using an electrospinning device.

1. Polyethylene terephthalate base material and binary material base material

The polyethylene terephthalate substrate serves as a support for maintaining the morphological stability in forming the filter media.

The fiber-forming polymer of the binary component used in the present invention may be a polyester including polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, and polybutylene terephthalate, and polypropylene terephthalate may also be polytrimethylene Terephthalate and polybutylene terephthalate such as polytetramethylene terephthalate.

The two-component base material in the present invention is most preferably polyethylene terephthalate to which two components having different melting points are bonded. The polyethylene terephthalate two-component substrate may be classified into a sheath-core type, a side-by-side type, a C-type, and the like. In the case of the sheath-core type two-component substrate, the sheath portion is a low melting point polyethylene terephthalate, and the core portion is made of general polyethylene terephthalate. Wherein the sheath portion is about 10 to 90 wt%, and the core is about 90 to 10 wt%. The sheath portion acts as a thermal binder to form the outer surface of the binder fiber, has a melting point of about 80 to 150 占 폚, and the core has a melting point of about 160 to 250 占 폚. The CIS type heterogeneous base material used as an embodiment in the present invention includes an amorphous polyester copolymer in which a melting point is not exhibited by a conventional melting point analyzer in the sheath portion and preferably a relatively high melting point component Is a thermally adhesive composite fiber to be used.

The polyester copolymer contained in the sheath portion is a copolyester in which 50 to 70 mol% is a polyethylene terephthalate unit. As the copolymerizable acid component, isophthalic acid is preferably used in an amount of 30 to 50 mol%, but any other conventional dicarboxylic acid may be used.

As a high melting point component used as a core component, a polymer having a melting point of 160 ° C or higher is suitable. Examples of the high melting point component include polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene terephthalate copolymer and polypropylene.

The basis weight of the ^two -component base is preferably 10 to 50 g / m ² , and the basis weight of the polyethylene terephthalate base is preferably 50 to 150 g / m ²

2. Organic polymer nanofiber nonwoven fabric laminated by electrospinning

Hereinafter, an organic polymer nanofiber nonwoven fabric manufactured using an electrospinning apparatus will be described.

The electrospinning apparatus of the present invention comprises a spinning liquid main tank for storing a spinning solution, a metering pump for supplying a spinning solution in a fixed amount, and a multiple tubular nozzle composed of a plurality of pins are combined in a block form, A collector for accumulating short fibers emitted at a position corresponding to the nozzle block, a voltage generating device for generating a high voltage, and a spinning solution discharging device connected to the top of the nozzle block.

A method of preparing an organic polymer nanofiber nonwoven fabric by electrospinning the organic polymer of the present invention will be described.

First, a spinning solution is prepared by dissolving the organic polymer in an acetone solvent. The spinning solution containing the organic polymer is stored in the spinning solution main tank, metered by a separate metering pump, and supplied to the spinning solution dropping device in a fixed amount.

In this way, the spinning solution supplied into the spinning solution dropping device is supplied to the spinning solution supply plate of the nozzle block in which a high voltage is applied discretely while passing through the spinning solution dropping device and the stirrer is installed. The spinning liquid drop device also blocks the flow of spinning liquid and prevents electricity from flowing into the spinning liquid main tank.

Subsequently, in the nozzle block, the spinning liquid is discharged through a nozzle to a collector at an upper portion where a high voltage is applied to produce nanofibers.

The spinning liquid transferred to the spinning liquid supply pipe is discharged to the collector through the nozzle to form fibers. At this time, the nanofibers electrified from the nozzles spread over the air sprayed from the nozzles for air supply, and are collected on the collector, thereby widening the collecting area and making the density of the particles uniform. The overspray fluid which is not fibrous in the nozzle is collected in the overflow removing nozzle and travels to the circulating fluid supply plate through the temporary storage plate of the overflow liquid.

The thickness of the organic polymer nanofiber nonwoven fabric, the diameter of the fiber, the shape of the fiber, and the mechanical characteristics of the separation membrane are changed according to the electrospinning process conditions such as the voltage applied, the kind of the polymer solution, the viscosity of the polymer solution, .

In the case of manufacturing nanofibers, the speed of air in the air supply nozzle is preferably 0.05 to 50 m / sec, more preferably 1 to 30 m / sec. When the velocity of the air is less than 0.05 m / sec, the dispersibility of the nanofibers collected in the collector is low, and the collecting area is not greatly improved. If the velocity of the air exceeds 50 m / sec, The area to be focused on the collector is rather reduced, and the more serious problem is attached to the collector in the form of coarse tufts rather than nanofibers, and the nanofiber forming ability and nanofiber forming ability are remarkably deteriorated.

At this time, in order to promote the formation of the fiber by the electric force, a voltage of 1 kV or more, more preferably 20 kV or more, generated by the voltage generator is applied to the conductive plate and collector provided at the lower end of the nozzle block. It is more advantageous in terms of productivity to use an endless belt as the collector. The collector preferably reciprocates a predetermined distance in the left and right directions to uniform the density of the nanofibers.

When the nanofibers formed on the collector are wound on a winding roller through a web supporting roller, the nanofiber manufacturing process is completed.

The organic polymer is preferably polyurethane or polyvinylidene fluoride. It is more preferable to use polyurethane or polyvinylidene fluoride as a conventional organic polymer material.

The polyvinylidene fluoride (PVDF) (hereinafter referred to as PVDF) is one of the fluorine-based polymers, and the fluororesin contains fluorine, which is excellent in thermal and chemical properties.

반응식 1. PVDF의 제조

Reaction 1. Preparation of PVDF

PVDF is prepared by the same process as in the above reaction formula 1, and has a melting point (177) and a density (1.78) lower than those of other fluororesin, and is cheap in chemical cost and low in unit cost. It is also used as an advanced paint for exterior walls.

In addition, PVDF is a representative organic material exhibiting piezoelectricity, and many studies have been conducted since the 1960s. In PVDF polymer, four kinds of crystals are mixed, and it can be divided into at least four types of α, β, γ and δ type depending on crystal form. Among them, β-type crystals of PVDF are filled with trans-type molecular chains in parallel, and all of the permanent dipoles of the monomers are aligned in one direction and exhibit large spontaneous polarization. This means that PVDF molecules are arranged regularly through stretching to impart piezoelectricity by giving anisotropy to the aggregated state. In order to improve such piezoelectric properties, various methods for increasing the? -Form crystal in the PVDF fiber have been studied.

In order to prepare the filter medium of the present invention, first, a polyvinylidene fluoride solution in which polyvinylidene fluoride is dissolved in an organic solvent is supplied to a spinning liquid main tank connected to each unit of the electrospinning device, The supplied solution is continuously supplied in a constant quantity into a plurality of nozzles of a nozzle block to which a high voltage is applied through a metering pump. The polyvinylidene fluoride solution supplied from each nozzle is electrospun and converged on a binary substrate placed on a collector with a high voltage applied thereto through a nozzle to form a polyvinylidene fluoride nanofiber nonwoven fabric laminate.

In the case of manufacturing nanofibers, the speed of air in the air supply nozzle is preferably 0.05 to 50 m / sec, more preferably 1 to 30 m / sec. If the velocity of the air is less than 0.05 m / sec, the collecting area of nanofibers is not so low and the collecting area is not greatly improved. If the velocity of the air exceeds 50 m / sec, And the more serious problem is attached to the collector in the form of coarse tuft, not the nanofiber, so that the ability to form nanofibers is remarkably deteriorated.

The basis weight of the organic polymer nanofiber nonwoven fabric is preferably 0.1 to 2 g / m ² .

After the polyvinylidene fluoride nanofiber nonwoven fabric is laminated by the above-mentioned method, the polyethylene terephthalate base material is laminated on the back end of the electrospinning device in such a manner that the polyvinylidene fluoride nanofiber nonwoven fabric is not laminated It is possible to produce a filter medium by bonding to one surface of a two-component substrate, bonding a meltblown and spunbond polypropylene nonwoven fabric to the polyvinylidene fluoride nanofiber nonwoven fabric, and ultrasonic bonding.

3. Polypropylene nonwoven fabric formed by meltblown and spunbond

The polypropylene nonwoven fabric has a hydrophobic property and has a water-resistant function as the outermost layer, and the meltblown polypropylene nonwoven fabric functions as a pre-filter for controlling the pore size in the filter medium .

Meltblown spinning is a technique for producing microfine fibers by injection of a polymer melt using compressed gas. Spandon spinning is a technique for producing a nonwoven fabric by dispersing a fiber by air treatment at high speed and dispersing it.

The polypropylene nonwoven fabric produced by the span bond is water repellent as an outer cover due to the bulky nature of the meltblown polypropylene nonwoven fabric. It also prevents ultraviolet rays to prevent sunlight corrosion.

The basis weight of the meltblown polypropylene nonwoven fabric is preferably 10 to 50 g / m ² , and the basis weight of the spunbonded polypropylene nonwoven fabric is preferably 20 to 80 g / m ²

The existing filter medium technique uses a filter medium of 3 to 4 sheets of polypropylene nonwoven fabric (30 mils) - meltblown polypropylene nonwoven fabric (25 mils) - polyethylene terephthalide (70 mils) Is about 50% thinner than conventional products, and it is more advantageous to bend for making thin bar cartridges.

As described above, when the two-component substrate is laminated on the polyethylene terephthalate substrate, the organic polymer nanofiber nonwoven fabric is laminated on the two-component substrate by electrospinning, and the polyolefin nanofiber nonwoven fabric is formed on the nanofiber nonwoven fabric by meltblown and spunbond Propylene nonwoven fabric is laminated to produce a filter medium for protecting electronic devices of the present invention.

4. Fabrication of Filter Assembly

The filter assembly comprises a filter frame and a filter media for protecting the electronics.

The filter frame is made of aluminum, stainless steel, plastic or the like, and has various shapes such as a square shape and a cylindrical shape.

The filter medium for protecting the electronic device is installed in the filter frame to produce the filter assembly of the present invention.

The filter assembly is preferably used for communication, outdoor advertising, or a digital information display (DID).

Hereinafter, the constitution and effects of the present invention will be described in detail with reference to specific examples and comparative examples. However, these examples are merely intended to clearly understand the present invention and are not intended to limit the scope of the present invention. The present invention will be described in detail with reference to the following non-limiting examples.

Example 1

Polyvinylidene fluoride having a weight average molecular weight (Mw) of 50,000 was dissolved in dimethylacetamide (N, N-dimethylacetamide, DMAc) to prepare a spinning solution, which was then introduced into the spinning liquid main tank of the electrospinning apparatus. The above spinning solution was electrospinned on the two-phase substrate under the conditions of a distance of 40 cm from the electrode, a voltage of 20 kV, a spinning solution flow rate of 0.1 mL / h, a temperature of 22 캜 and a humidity of 20% to prepare a polyvinylidene fluoride A rid nanofiber nonwoven fabric was laminated on a 2-μm-thick two-component substrate. The two-component base material is a sheath-core type and has a basis weight of 30 g / m ² . After electrospinning, polyethylene terephthalate having a thickness of 10 占 퐉 was bonded to one surface of the two-component base material on which the polyvinylidene fluoride nanofiber nonwoven fabric was not laminated, and on the laminated polyvinylidene fluoride nanofiber nonwoven fabric, A meltblown polypropylene nonwoven fabric and a spunbonded polypropylene nonwoven fabric were bonded to each other. The basis weight of the polyethylene terephthalate base material was 70 g / m ² , the basis weight of the meltblown polypropylene nonwoven fabric was 25 g / m ² , and the basis weight of the spunbond polypropylene nonwoven fabric was 30 g / m ² . Thereafter, this was ultrasonically bonded to produce a filter medium. The fabricated filter media was installed in the filter frame to produce a filter assembly.

Example 2

A filter medium was prepared under the same conditions as in Example 1 except that the organic polymer of the nanofiber nonwoven fabric was changed to polyurethane, and the filter medium was installed on the filter frame to prepare a filter assembly.

Comparative Example 1

The thickness 5㎛, 30g / m ² 5㎛ polypropylene non-woven fabric, the thickness of the basis weight and the basis weight of 25g / m ² of a meltblown polypropylene nonwoven fabric layer 4 and the thickness 10㎛ a basis weight of 70g / m ² of polyethylene terephthalate substrate A filter assembly was prepared by fabricating a stacked filter media in order and installing it on a filter frame.

Comparative Example 2

Thickness 5㎛, 30g / m ² 5㎛ polypropylene non-woven fabric, the thickness of the basis weight and the basis weight of 25g / m ² of meltblown polytetrafluoroethylene (ePTFE) 10㎛ non-woven layer 4 and the thickness and basis weight of 70g / m ² , And the filter media was installed in a filter frame to prepare a filter assembly.

The prepared examples and comparative examples measured the initial dust collecting efficiency and the pressure loss after initial and dust loading.

- Test equipment configuration: Duct for dust collection efficiency, particle generator (KCl 1% W / V), dust disperser (JIS 11), particle counter (Aerosol Spectrometer Model: 1.109, Grimm, Germany) Testo 350-M / XL * testo 545, Testo, Germany)

- Tested dust: 0.3 ㎛ particle size KCl particles and JIS 11 dust

- Dust collection efficiency test

The filter was attached to the test duct, and the flow rate of the test was measured. After confirming that the particle concentration was stable, the particle concentration on the upstream side and the downstream side were alternately measured, and the initial dust collecting efficiency of 0.35 탆 was measured and the results are shown in Table 1.

The dust collection efficiency is calculated by the following formula.

侶 = (1 - C ₀ / C _i ) × 100

η = dust collection efficiency (%)

C ₀ = number of downstream sides (number / m ³ )

C _i = number of upstream side concentration (number / m ³ )

- Pressure loss test after dust loading

The filter was attached to the test duct and the JIS 11 dusts were placed on the filter surface at a concentration of 714.2857 gm / m ^3. After the filter surface velocity was 0.3 m / s, the upstream side and the downstream side The pressure loss was measured and the pressure loss at 0, 300g dust loading is shown in Table 2.

The pressure loss is calculated by the following formula.

ΔP = P ₁ - P ₂

DELTA P = pressure loss (Pa)

P ₁ = upstream pressure (Pa)

P ₂ = downstream pressure (Pa)

Test conditions were conducted at a temperature of 25-28 ° C and a relative humidity of 55-60%.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 0.35 탆 DOP
Filtration efficiency (%) 99.3 99.1 98.4 98.5

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Pressure loss at 0 g dust load 36.6 38.1 42.9 42.1 Pressure loss at dust load of 300g 189.1 192.3 201.1 204.8

According to Table 1 and Table 2, the filter assembly manufactured through the embodiment of the present invention is superior to the comparative example due to the high initial dust collection efficiency and low pressure loss.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. Anyone with it will know easily.

Claims (3)

A basis weight of 50 to 150 g / m ² A polyethylene terephthalate substrate;
A bicomponent substrate laminated on the polyethylene terephthalate substrate and having a basis weight of 10 to 50 g / m ² ;
A basis weight of 0.1 to 2 g / cm < 2 > formed by electrospinning at a distance of 40 cm from the electrode to the collector, an applied voltage of 20 kV, a spinning liquid flow rate of 0.1 mL / h, a temperature of 22 DEG C, m < ^{2 &} gt ;;
A meltblown polypropylene nonwoven fabric having a basis weight of 10 to 50 g / m ² laminated on the organic polymer nanofiber nonwoven fabric; And
And a spunbonded polypropylene nonwoven fabric having a basis weight of 20 to 80 g / m ² laminated on the meltblown polypropylene nonwoven fabric,
Wherein the organic polymer is polyurethane or polyvinylidene fluoride,
The two-component substrate may be any one selected from a sheath-core type, a side by side type, and a C-type type.
Wherein the filter has a diameter of 0.3 mu m, a DOP filtration efficiency of 99.1% or more, a pressure loss of 38.1 Pa or less when the dust loading amount is 0 g, and a pressure loss of 192.3 Pa or less when the dust loading amount is 300 g. An electronic device protection filter medium according to claim 1; And
And a filter frame on which the filter medium for protecting an electronic device is installed.
3. The method of claim 2,
Wherein the filter assembly for protecting an electronic device is for communication, outdoor advertisement, or digital information display (DID).