阅读说明：本技术 一种新风用过滤芯 (Filter element for fresh air ) 是由 杨大伟 刘同娟 于 2019-02-20 设计创作，主要内容包括：本发明公开一种新风用过滤芯,该滤芯至少包括一层静电驻极熔喷无纺布作为主过滤层,所述熔喷无纺布的表面每500平方微米主面上2条以上纤维接着点的平均个数不多于8个,所述熔喷无纺布的嵩高性为3.0～15.0cm<Sup>3</Sup>/g。本发明的新风过滤芯具有高容尘、高捕集效率的特点。(The invention discloses a filter element for fresh air, which at least comprises a layer of electrostatic electret melt-blown non-woven fabric as a main filter layer, wherein the average number of more than 2 fiber connection points on each 500 square microns main surface of the melt-blown non-woven fabric is not more than 8, and the melt-blown non-woven fabric has the bulk high property of 3.0-15.0 cm 3 (ii) in terms of/g. The fresh air filter element has the characteristics of high dust holding capacity and high trapping efficiency.)

1. The utility model provides a new trend is with crossing filter core which characterized in that: the filter element at least comprises a layer of electrostatic electret melt-blown non-woven fabric as a main filter layer, and the surface of the melt-blown non-woven fabric is 500 square microns per square micronThe average number of the bonding points of more than 2 fibers on the main surface is not more than 8, and the bulk height of the melt-blown non-woven fabric is 3.0-15.0 cm³/g。

2. The filter element for fresh air according to claim 1, wherein: the average pore diameter of the melt-blown non-woven fabric is less than 60 mu m.

3. The filter element for fresh air according to claim 1, wherein: the average diameter of the fibers constituting the melt-blown nonwoven fabric is 1.0 to 7.0 μm.

4. The filter element for fresh air according to claim 1, wherein: the filter element comprises a pre-filtering layer composed of fibers with an average diameter of 15-50 μm.

5. The filter element for fresh air according to claim 1, wherein: the fiber forming the melt-blown non-woven fabric is at least one material of polyester, polyamide and polypropylene.

6. The filter element for fresh air according to claim 1, wherein: the gram weight of the melt-blown non-woven fabric is 15-30 g/m²。

7. The filter element for fresh air according to claim 1, wherein: the thickness of the melt-blown non-woven fabric is 0.10-0.30 mm.

8. The filter element for fresh air according to claim 1 or 2, wherein: under the conditions that the test wind speed is 5.33cm/s and the pressure loss is stopped to be 250Pa, the dust holding capacity of the filter element is 20g/m²The above.

9. The filter element for fresh air according to claim 1 or 2, wherein: under the condition of a test wind speed of 5.33cm/s, the primary collection efficiency of the filter element on polystyrene particles with the particle size of 0.3-0.5 mu m is more than 95.0%.

Technical Field

The invention relates to a filter element for fresh air.

Background

With the continuous development of society and economy in China, the living standard of people is continuously improved, and the requirement of people on the indoor environment air quality is higher and higher. At present, the widely used air purifier can only circularly treat the air in a closed room, and has the defects of insufficient oxygen content and concentration of the air and incapability of exchanging temperature and humidity with the outside. The fresh air system is an air treatment system consisting of an air supply system and an air exhaust system, outdoor fresh air can be introduced into a room through the fresh air system, but a large amount of pollutants such as dust, hair and the like exist in the outdoor air, so that a filter core is required to be arranged in the fresh air system, and the filter core can treat pollutants such as PM2.5 and the like introduced into the air. Dust holding capacity and collecting efficiency are two very important indexes of the fresh air filter element, the dust holding capacity directly determines the service life and the replacement cost of the fresh air filter element, and the collecting efficiency directly determines the cleanness degree of air led into a room through a fresh air system.

At present, part of filter core materials in the market use multilayer composite structure, and the space between the fibre is reduced as far as possible, reaches the effect of high entrapment efficiency, however because the space between the fibre is little, the dust volume that inside can be stored is also few promptly holding the dirt volume, has consequently shortened the life of filter core. In order to increase the dust holding capacity of the filter element, some melt-blown filter layers with thicker fiber diameters are adopted, and the dust holding capacity of the obtained filter element is high due to the enlargement of gaps among fibers, but the collection efficiency of the filter element on particulate matters is reduced due to the large gaps among the fibers, so that the filtering effect of the filter element is poor.

For example, the Chinese patent publication CN108722032A discloses a filter material for a building fresh air system, which comprises a PVC filter membrane, a PAN filter membrane, a microstructure PVC filter membrane and a microstructure PA66 filter membrane from bottom to top, wherein multiple types of single-layer filter materials are superposed by an electrostatic spinning method to form the filter material with very small probability of completely penetrating gaps and high filter efficiency. However, since the gaps between the materials are small, the amount of dust that can be stored inside, i.e., the dust holding amount, is also small, thereby shortening the service life of the filter material.

For another example, chinese patent publication CN204898434U discloses a double-layer composite filter paper for a pleated air filter, which includes a melt-blown nonwoven fabric layer and a glass fiber filter layer, wherein the fiber diameter of the melt-blown nonwoven fabric layer is 0.5-10 μm. The diameter of the fiber forming the melt-blown non-woven fabric is thick, and gaps among the fibers are large, so that the trapping efficiency of the air filter on particulate matters is reduced, and the filtering effect of the air filter is poor.

Disclosure of Invention

The invention aims to provide a filter element for fresh air, which has high dust capacity and high trapping efficiency.

The technical solution of the invention is as follows: the filter element for fresh air at least comprises a layer of electrostatic electret melt-blown non-woven fabric as a main filter layer, the average number of more than 2 fiber connection points on each 500 square microns main surface of the melt-blown non-woven fabric is not more than 8, and the melt-blown non-woven fabric has the bulk high property of 3.0-15.0 cm³/g。

The average pore diameter of the meltblown nonwoven fabric is preferably less than 60 μm.

The average diameter of the fibers constituting the melt-blown nonwoven fabric is preferably 1.0 to 7.0 μm.

The filter element preferably comprises a pre-filtering layer consisting of fibers with the average diameter of 15-50 mu m.

The fibers constituting the meltblown nonwoven fabric are preferably at least one material selected from the group consisting of polyester, polyamide and polypropylene.

The gram weight of the melt-blown non-woven fabric is preferably 15-30 g/m²。

The thickness of the melt-blown nonwoven fabric is preferably 0.10 to 0.30 mm.

Under the conditions that the wind speed is 5.33cm/s and the pressure loss is 250Pa, the dust holding capacity of the filter element is preferably 20g/m²The above.

Under the condition that the test wind speed is 5.33cm/s, the primary collection efficiency of the filter element on polystyrene particles with the particle size of 0.3-0.5 mu m is preferably more than 95.0%.

The invention has the beneficial effects that: the filter element for fresh air solves the problems of low dust holding capacity and low trapping efficiency of the conventional filter element, and reduces the replacement period of the filter element. The fresh air filter element has the characteristics of high dust holding capacity and high trapping efficiency.

Detailed Description

The filter element for fresh air at least comprises a layer of electrostatic electret melt-blown non-woven fabric as a main filter layer, the average number of more than 2 fiber connection points on each 500 square microns main surface of the melt-blown non-woven fabric is not more than 8, and the melt-blown non-woven fabric has the bulk high property of 3.0-15.0 cm³(ii) in terms of/g. The melt-blown non-woven fabric is subjected to electrostatic electret treatment, so that the surface of the melt-blown non-woven fabric is provided with uniformly distributed positive and negative charges, and the effect of filtering small particles is achieved through the attraction effect of the charges on particles. The number of fiber attachment points per unit area of the meltblown nonwoven fabric directly affects the collection efficiency and dust holding capacity of the material, and if the average number of 2 or more fiber attachment points per 500 square micrometers of the major surface of the meltblown nonwoven fabric is greater than 8, it means that the attachment between the fibers is very tight, resulting in small gaps between the fibers, and although the collection efficiency of the filter element is improved, the amount of particulate matter dust held inside the filter element is reduced, i.e., the dust holding capacity is reduced. Along with the operation of the fresh air system, dust in the outdoor airCan gather on the top layer and the nexine of filter element gradually to fill the inside space of melt-blown non-woven fabrics, be obstructed when causing the air to pass through, at this moment, filter element pressure loss risees, and effective air output diminishes. When the dust volume that the filter core held reached the maximum value, just reached the life of filter core, must change the filter core this moment, otherwise the new trend system can no longer supply sufficient clean air to indoor. Therefore, in the same use environment, if the dust holding amount is low, the time required for the filter element to reach the maximum dust holding amount is short, thereby shortening the service life of the filter element.

When the average number of the fiber attachment points is measured, the attachment points among more than 2 fibers on the main surface of every 500 square microns of the surface of the melt-blown non-woven fabric are adopted. The production process of the melt-blown non-woven fabric comprises the steps of melting fiber slices, extruding and spraying the melted fiber slices through a spray head, falling the fiber slices on a roller layer by layer, cooling to form the melt-blown non-woven fabric, microscopically, mutually disordered and interweaved and laminated fibers, wherein an interweaving area of the fibers is called a fiber joint point, the interweaving degree of more than 2 fibers can be visually reflected by the number of the fiber joint points, and if the number of the fiber joint points of more than 2 fibers is more, the higher the interweaving degree of the fibers is, the tighter the arrangement is and the.

The fleshy and high performance of the melt-blown non-woven fabric can influence the filtering effect of the filter element, and if the fleshy and high performance of the melt-blown non-woven fabric is more than 15.0cm³The volume of the melt-blown non-woven fabric per unit mass is large, the thickness of the melt-blown non-woven fabric is thick, and stacking gaps among fibers are large, so that the trapping efficiency of the filter element on particulate matters is reduced, and the filtering effect of the filter element is poor; if the melt-blown nonwoven fabric has a bulk-height of less than 3.0cm³The volume of the melt-blown non-woven fabric per unit mass is small, the thickness of the melt-blown non-woven fabric is small, stacking gaps among fibers are small, the amount of particulate dust contained in the filter element is reduced, namely the dust containing amount is reduced, and therefore the service life of the filter element is shortened. In consideration of the balance between dust holding capacity and collection efficiency, the average number of 2 or more fiber-bonded points per 500 square micrometers of main surface of the meltblown nonwoven fabric of the present invention is preferably 3 to 6, and the melt-blown nonwoven fabric has a bulk height of preferably 9.0 to 15.0cm³/g。

The average pore diameter of the meltblown nonwoven fabric is preferably less than 60 μm. 60% of dust in the atmosphere has a particle size range larger than 60 mu m, if the average pore size of the melt-blown non-woven fabric is too large, the fiber arrangement is sparse, and atmospheric dust is not easy to collide and adsorbed on the fiber surface after entering the melt-blown non-woven fabric, but directly escapes through gaps among the fibers, so that the trapping efficiency of the melt-blown non-woven fabric on particulate matters is reduced, and the filtering effect of the filter element is poor.

The average diameter of the fibers constituting the melt-blown nonwoven fabric is preferably 1.0 to 7.0 μm. If the average diameter of the fibers constituting the melt-blown nonwoven fabric is too low, the fibers are fine and the fibers are stacked tightly, so that the number of bonding points between the fibers is increased, the internal gaps between the melt-blown nonwoven fabrics are small, the amount of particulate dust contained in the filter element is reduced, that is, the dust containing amount is reduced, and the service life of the filter element is shortened; if the average diameter of the fibers forming the melt-blown non-woven fabric is too high, the fibers are thick, the fibers are stacked sparsely and are not arranged tightly, and then the stacking gap between the fibers is large, so that the trapping efficiency of the filter element on particulate matters is reduced, and the filtering effect of the filter element is poor. In consideration of the balance between the dust holding capacity and the collecting efficiency of the filter element, the average fiber diameter of the meltblown nonwoven fabric of the present invention is more preferably 2.0 to 5.0 μm.

The filter element preferably comprises a pre-filtering layer consisting of fibers with the average diameter of 15-50 mu m. The pre-filtering layer plays a role in pre-filtering particles in the air and mainly filters particles with large particle sizes. If the average diameter of the pre-filtering layer is too low, the fibers are thin and are tightly arranged, so that the pre-filtering filter has a good filtering effect, but the pre-filtering fibers are thin, so that the material has low rigidity and is soft as a whole, the pre-filtering filter cannot play a role in supporting the pre-filtering filter in the folding and forming process of the filtering material, the formed filtering core is soft as a whole, the pre-filtering filter is easy to deform when being impacted by wind, the resistance of wind passing is increased, and the pressure loss of the manufactured filtering core is large; if the average diameter of the pre-filtering layer is too large, the fibers forming the pre-filtering layer are thick, the contact points between the fibers are reduced, the fiber arrangement is loose, the fiber gaps are large, and the obtained filter element has low pressure loss but cannot play a role in intercepting large-particle-size particles, so that the trapping efficiency of the filter element is reduced, and the filtering effect is poor. In consideration of the balance between the pressure loss of the filter element and the collection efficiency (for large-particle-diameter particulate matter), the average diameter of one prefilter layer included in the filter medium of the present invention is more preferably 20 to 40 μm. The nonwoven fabric constituting the pre-filter layer is preferably a thermally bonded nonwoven fabric, a chemically bonded nonwoven fabric, or a wet-process nonwoven fabric.

The fibers constituting the meltblown nonwoven fabric are preferably at least one material selected from the group consisting of polyester, polyamide and polypropylene. Electret is added into the master batch of the material, melt-blown non-woven fabric is formed through processes of melt-blowing, spinning, net forming, cooling and the like, and the prepared melt-blown non-woven fabric is subjected to pure water friction or high-voltage corona treatment to form semi-permanent electrification, so that electrostatic electret melt-blown non-woven fabric is formed, the electrostatic electret melt-blown non-woven fabric can adsorb fine particles, and the dust trapping efficiency of the prepared filter element can be greatly improved. The raw material of the melt-blown non-woven fabric is at least one of polyester, polyamide and polypropylene, because the materials have wide sources, simple manufacturing process, low cost and good hydrophobic property, the absorption of moisture in air can be effectively reduced after electrostatic processing, and the moisture in the air is a good conductor, which can cause the static charges on the surface of the melt-blown non-woven fabric to flow and be mutually neutralized, so that the electrostatic action is weakened, and the melt-blown non-woven fabric made of the hydrophobic materials can keep long-term charge after electrostatic processing.

The gram weight of the melt-blown non-woven fabric is preferably 15-30 g/m². If the weight of the unit area of the melt-blown non-woven fabric is too small, the fiber quantity of the unit area is small, the contact points between the fibers are also small, the arrangement is loose, although the dust quantity which can be accommodated in the filter element is high, the collection efficiency of the particles is lower, and the filtering effect is poor. If the weight per unit area of the meltblown nonwoven fabric is too large, the amount of fibers per unit area is large, and the number of contact points between fibers is also large, so that the efficiency of collecting the fibers by the filter element is high, but the amount of dust to be accommodated is low because the pores in the material are small. Considering the balance between the collection efficiency and the dust holding capacity of the filter element, the gram weight of the melt-blown non-woven fabric is more preferably 20-30 g/m²。

The thickness of the melt-blown nonwoven fabric is preferably 0.10 to 0.30 mm. If the thickness of the melt-blown non-woven fabric is too small, the number of fiber bonding points is large, the fibers are tightly stacked, gaps among the fibers are small, and the dust holding capacity of the filter element is low; if the thickness of the melt-blown non-woven fabric is too large, the fiber adhesive force is small and the melt-blown non-woven fabric is in a fluffy state, and the surface hairiness of the melt-blown non-woven fabric is serious, so that the appearance and the subsequent bonding processing are influenced. Considering the dust holding capacity performance of the filter element and the appearance processing of the material, the thickness of the melt-blown non-woven fabric is more preferably 0.20-0.28 mm.

Under the conditions that the wind speed is 5.33cm/s and the pressure loss is 250Pa, the dust holding capacity of the filter element is preferably 20g/m²The above. The dust holding capacity depends on the size of the meltblown nonwoven voids, which in turn is related to the grammage, fiber diameter, thickness, etc. of the layer. The smaller the gram weight, the larger the fiber diameter and the larger the thickness, the larger the dust holding capacity of the material is, and the larger the dust holding capacity of the filter element is.

Under the condition that the test wind speed is 5.33cm/s, the primary collection efficiency of the filter element on polystyrene particles with the particle size of 0.3-0.5 mu m is preferably more than 95.0%. The filter element has high primary collection efficiency, which shows that the filter material has small fiber diameter and high gram weight and can effectively intercept dust. If the primary collection efficiency of the filter element is too low, most dust in the air directly passes through the filter element to enter the room, so that the indoor environment is deteriorated and the filter element cannot play a role in filtering.

The manufacturing method of the filter element for fresh air comprises the following steps:

(1) preparation of electrostatic electret melt-blown nonwoven fabric-spinning: feeding the master batch containing the electret into a screw extruder, fully heating and melting, then spraying out from a spinneret orifice of a melt-blowing die head through a melt filter and a metering pump, cooling by cooling air blown out from pipelines at two sides during the process, and then dropping on a trapping roller.

(2) Preparation of electrostatic electret melt-blown nonwoven-web formation: the fiber sprayed from the spinneret orifice falls on a trapping roller with micropores distributed on the surface, and then the fiber is mutually consolidated and formed into a net under the suction action of a fan in the roller.

(3) Preparation of electrostatic electret melt-blown nonwoven fabric-electrification processing: and cooling the formed melt-blown non-woven fabric, and carrying out electrification processing to obtain the melt-blown non-woven fabric with static electricity.

(4) Preparing a filter material and a filter element: and (3) scattering hot-melt adhesive powder on the binding surface of the pre-filtering layer, heating the pre-filtering layer in a grading oven, and binding the pre-filtering layer after the pre-filtering layer is discharged from the oven with the electrostatic electret melt-blown non-woven fabric to form the filter material. And folding and gluing the filter material to finally obtain the filter element for the fresh air.

The present invention will be further illustrated by the following examples, but the scope of the present invention is not limited to the examples, and the physical property parameters in the examples are measured by the following methods.

[ fiber splicing Point ]

Selecting melt-blown non-woven fabric with a size of 50 × 10mm, selecting 10 positions with clear imaging fibers uniformly distributed under the magnification of 1000 by an electron scanning microscope SEM (Shimadzu corporation, model SS-550), taking pictures, selecting 10 regions (500 square micron main surfaces) with a length of 50 microns and a width of 10 microns on each picture, and recording the number of the interweaving points of 2 fibers in each region as P₁Recording the number of mutually interwoven points of 3 fibers as P₂Recording the number of mutually interwoven points of 4 fibers as P₃And so on, the number of the fiber following points of more than 2 fibers in the area is P = P₁+P₂+P₃+…P_n. According to the above procedure, the surface of 100 meltblown nonwoven fabrics was tested for 2 or more fiber attachment points per 500 square micrometers of the major surface, and the average value was calculated.

[ average diameter of fiber ]

The melt-blown nonwoven fabric was photographed with a scanning electron microscope SEM (model SS-550, shimadzu corporation) at a magnification of 2000 times, the number of test samples was 5, 20 fiber diameter points were uniformly taken for each sample, and then the diameter distribution and the average value were analyzed for 100 fiber diameter points.

[ average pore diameter ]

The average pore diameter of the melt-blown non-woven fabric is measured by a PMI capillary flow pore tester (model CFP-1100-AX) according to the measurement of GB/T24219-. The number of test samples was 10, and the final average value was taken.

[ gram weight ]

The grammage of the filter material was measured using an electronic balance (model JA 1003) according to JISL 1913-2010 measurement, and the results were directly read by a test instrument. The number of test samples was 10, and the final average value was taken.

[ thickness ]

The thickness of the filter was measured by a thickness measuring instrument (model FS-60DS, manufactured by Kyoeishi Seiki Seisakusho K.K.) according to the measurement of JISL 1913-. The number of test samples was 10, and the final average value was taken.

High-toughness

The calculation formula of the bulk and high property of the melt-blown non-woven fabric is as follows: high-tenacity = 1/gram weight x thickness, wherein high-tenacity is the volume of a material per unit weight, and the higher the high-tenacity, the bulkier the meltblown nonwoven fabric is; the lower the fleshy nature, the denser the meltblown nonwoven.

[ dust holding amount ]

The dust holding capacity of the filter element was measured in accordance with ISO11155-1, and the air flow rate was measured at 5.33cm/s using a particle size analyzer (TOPAS GmbH, Germany) and ISOA2 dust.

[ trapping efficiency ]

According to the JIS B9908-2001 standard, the test air volume is 5.33cm/s, and the test is carried out by using 0.3-0.5 mu m neutralization KCl aerosol particles, wherein the calculation formula is as follows:

number of particles (number) in upflow: the quantitative gas on the upper side of the filter element airflow contains the number of KCl aerosol particles;

number of particles (number) to flow down: the number of KCl aerosol particles contained in the quantitative gas on the upper side of the filter element airflow is determined.