Preparation method of deformation-resistant high-dust-holding-capacity filter bag material

Abstract

The invention relates to the technical field of filter materials, and discloses a preparation method of a deformation-resistant high-dust-holding-capacity filter bag material.According to the method, a framework layer, a non-woven fabric filter layer, an electrostatic layer and a non-woven fabric filter layer are compounded into the deformation-resistant high-dust-holding-capacity filter bag material through melt spinning composite treatment. The skeleton layer is prepared from modified polypropylene prepared from modified graphene hollow spheres and polypropylene, the gram weight of the prepared skeleton layer is 30-60 g / m < 2 >, the thickness is 0.4-0.6 mm, the fiber yarn diameter is 40-60 microns, and after the skeleton layer is compounded with the electrostatic layer and the non-woven fabric filter layer, the stiffness of the filter material can be remarkably improved; the stiffness test of the deformation-resistant high-dust-holding-capacity filter bag material can reach 72-83%, and the deformation resistance is remarkably enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of filter materials, and in particular to a method for preparing a deformation-resistant high-dust-holding filter bag material. Background Art

[0002] The bag filter is a new type of filtration system with novel structure, small size, simple and flexible operation, energy saving, high efficiency and strong applicability. The filter bag inside is used to intercept the medium to play a filtering role. The filter material of the filter bag usually adopts filter materials with different filtration efficiency according to different filtration requirements. Currently, the commonly used filter materials are fiber fabrics and polymer films.

[0003] The prior art points out that the larger the filtering area of ​​the filter bag, the higher the filtering efficiency. Therefore, in order to increase the specific surface area of ​​the filter bag in a limited filter, the prior art proposes a technical solution for a pleated filter, such as a filter bag, a pleated filter material of the filter bag, and a manufacturing method thereof disclosed in Publication No. CN102196851B. Since the materials used in the pleated filter bag are mostly deformable fiber fabric polymer films, part of the material of the deformed filter bag will be stacked during use, resulting in the inability to filter the stacked part, thereby failing to fully ensure the efficient filtration of the bag filter. Therefore, in order to solve the above problem, the prior art proposes adding a support skeleton layer to the filter material and using a stiffening agent for treatment, such as Publication No. CN 113209726 B discloses a method for preparing a stiff filter material for a pleated filter bag, and another example is a filter material and its use disclosed in publication number CN101934173A; during use, the present invention found that adding a supporting skeleton layer to the filter material would increase the thickness and gram weight of the filter, reduce the specific surface area of ​​the filter bag within the limited filter volume, and increase the production cost; and when the filter material is treated with a stiffening agent, there will be problems such as reduced filter pores and large deviations in filtration performance, resulting in the filter material being unable to meet usage requirements. Summary of the invention

[0004] In order to overcome the problems of easy deformation and poor stiffness of filter bag materials in the prior art, the present invention provides a method for preparing a deformation-resistant and high-dust-holding capacity filter bag material; the method adopts a non-woven process to prepare the filter material, and a polypropylene material modified by hollow graphene balls is melt-blown to form a synthetic skeleton layer, and then the skeleton layer is composited with a non-woven fabric filter layer and a classic layer to form a deformation-resistant and high-dust-holding capacity filter bag material; the skeleton layer of the method adopts melt spinning to form a three-dimensional fluffy structure formed by polypropylene fibers, and the structure has high stiffness, deformation resistance and light weight, thereby ensuring that filter material stacking due to deformation will not occur during the use of the bag filter, thereby ensuring the efficient operation of the filter.

[0005] The specific technical scheme of the present invention is: A method for preparing a deformation-resistant high-dust-holding capacity filter bag material, comprising: a skeleton layer being melt-blown compositely treated to the surface of an electrostatic filter layer to form the deformation-resistant high-dust-holding capacity filter bag material, the skeleton layer being made of modified polypropylene, the modified polypropylene being mixed with graphene hollow spheres, a dispersant and polypropylene as raw materials, and the electrostatic filter layer being made of melt-blown non-woven fabric fiber polyester being melt-blown compositely treated to the surfaces of both sides of the electrostatic cotton.

[0006] Preferably, the dispersant is selected from one or more of dimethylformamide, sodium lignin sulfonate and sodium dodecylbenzene sulfonate.

[0007] Preferably, the hollow graphene spheres are made from a carbon source, a surfactant and a catalyst as raw materials through calcination and acid washing.

[0008] Preferably, the carbon source is glucose.

[0009] Preferably, the surfactant is one or more of polyvinyl alcohol and polyethylene glycol.

[0010] Preferably, the catalyst is selected from one or more of nickel salts, cobalt salts and iron salts.

[0011] Preferably, the calcination treatment includes one-stage calcination, two-stage calcination and three-stage calcination.

[0012] Preferably, the conditions of the first stage calcination include: temperature of 100 to 160° C. and time of 5 to 24 hours.

[0013] Preferably, the conditions for the second-stage calcination include: temperature of 300-500° C. and time of 10-30 minutes.

[0014] Preferably, the conditions for the three-stage calcination include: nitrogen atmosphere, temperature 1000-1100° C., and time 1-2 hours.

[0015] Preferably, the added amount of the modified hollow graphene spheres is 0.1-1%.

[0016] Preferably, the mixing conditions include: a feeding section temperature of 110-120°C, a conveying section temperature of 125-135°C, a melting section temperature of 135-145°C, and an extrusion section temperature of 140-150°C.

[0017] Preferably, the conditions for the skeleton melt-blown composite treatment include: spinneret temperature 170-200°C, head pressure 18-20bar, stretching air flow pressure 0.4-0.45bar, side blowing air flow temperature 23-25°C; hot rolling roller temperature 130-145°C, hot rolling roller pressure 80-90daN / cm, hot rolling speed 600-650m / min.

[0018] Preferably, the conditions for the filtration melt-blown composite treatment include: a spinning temperature of 200 to 300°C, a head pressure of 30 to 35 bar, a stretching airflow pressure of 0.5 to 0.7 bar, a side-blowing airflow temperature of 23 to 25°C, a roller pressure of 100 to 110 daN / cm, a roller speed of 400 to 500 m / min, a smooth roller pressure of 70 to 80 daN / cm, and a smooth roller speed of 600 to 650 m / min.

[0019] The invention provides a preparation method of a deformation-resistant high-dust-holding filter bag material. The method adopts a melt spinning method to compound a skeleton layer on a filter layer. The skeleton layer is made of modified polypropylene melt spinning obtained by using graphene hollow balls and polypropylene as raw materials. The skeleton layer has a three-dimensional fluffy structure and can be used as a pre-filtering layer of a filter layer to pre-intercept large particles such as paper scraps, hair, leaves, dust, etc., thereby improving the filtering efficiency of a subsequent filter layer and the service life of the filter material. In addition, the invention uses graphene hollow balls as fillers of polypropylene, which can significantly increase the fiber strength of polypropylene and the stiffness of the filter material, so that the skeleton layer has a deformation-resistant effect, and ensures that the filter bag will not have the problem of filter bag stacking due to deformation during use. Compared with other fillers and solid fillers, the graphene hollow balls have the characteristics of large specific surface area, low density and light weight. When used as fillers, the weight of the fiber does not change significantly, and the hollow spherical graphene can be better dispersed in a polyester material. Only a small amount of graphene hollow balls is needed to significantly enhance the fiber strength of the polyester fiber and increase the stiffness of the filter bag.

[0020] The electrostatic filter layer in the present invention is made of melt-blown non-woven fiber polyester on both sides of the electrostatic layer. The electrostatic cotton can assist the non-woven fabric to filter out particles below 1 μm, thereby improving the filtering accuracy of the filter bag and increasing the service life of the filter bag.

[0021] Compared with the prior art, this application has the following technical effects: The present invention provides a method for preparing a deformation-resistant high dust holding capacity filter bag material. The method adopts melt spinning composite treatment to composite a skeleton layer, a non-woven fabric filter layer, an electrostatic layer and a non-woven fabric filter layer into a deformation-resistant high dust holding capacity filter bag material. The method does not use a coating and an adhesive. The skeleton layer is made of modified graphene hollow balls and modified polypropylene made of polypropylene. The gram weight of the prepared skeleton layer is 30 to 60 g / m 2 The thickness is 0.4-0.6mm, the fiber diameter is 40-60μm. After the above-mentioned skeleton layer is compounded with the electrostatic layer and the non-woven filter layer, the stiffness of the filter material can be significantly improved. The stiffness test of the deformation-resistant and high dust-holding capacity filter bag material can reach 72-83%, and the deformation resistance is significantly enhanced. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the embodiments.

[0023] Embodiment 1: A method for preparing a deformation-resistant high-dust-holding filter bag material comprises the following steps: Preparation of hollow graphene spheres: 1 g of glucose, 5 g of polyvinyl alcohol, and 0.01 g of ferric chloride are added to 40 ml of deionized water and stirred to form a slurry, and the slurry is injected into a high-pressure reaction vessel for a first-stage calcination at a temperature of 130° C. for 12 hours. After the reaction vessel is cooled, the solid is separated; the solid is dried and placed in a microwave heating furnace for a second-stage calcination at a temperature of 300° C. for 30 minutes. After cooling, the solid is separated; the solid is placed in a tubular furnace and heated at 1000° C. for 2 hours under a nitrogen atmosphere. After cooling, the product is immersed in a hydrochloric acid solution (concentration 1 mol / L) for 12 hours, and the graphene hollow spheres (particle size of 3 to 15 nm) are obtained after being cleaned with deionized water and dried; Preparation of modified polypropylene: The prepared graphene hollow spheres are dispersed in a dispersion liquid (the mass ratio of dimethylformamide, sodium lignin sulfonate and sodium dodecylbenzene sulfonate is 1:0.01:0.05) to prepare a dispersion slurry, and then the polypropylene masterbatch is injected into a mixer, and the dispersion slurry is added from the side material port of the mixer (the graphene addition amount is 0.1%) and extruded to obtain modified polypropylene; the melt mixing conditions include: a feeding section temperature of 110°C, a conveying section temperature of 125°C, a melting section temperature of 135°C, and an extrusion section temperature of 140°C; Preparation of electrostatic filter layer: The electrostatic layer is ES hot air electrostatic cotton (20g / cm 2 ), putting polypropylene slices and polybutylene terephthalate slices into a drying oven for drying, injecting the dried polypropylene slices, polybutylene terephthalate and chlorinated biphenyl into a mixer for mixing to form a melt-blown non-woven polyester, injecting the melt-blown non-woven polyester slices into a screw extruder for melting and extrusion and injecting them into a spinneret, and spraying filaments from the head of the spinneret, and the filaments are stretched into ultra-fine fibers under the action of the airflow of the bellows, and the fibers are compounded on the surface of the electrostatic layer after cold air heat exchange, and the electrostatic filter layer is formed by hot pressing with a flower roller and a flat roller, and the two layers of the electrostatic layer are respectively compounded with a layer of melt-blown non-woven fabric, and the melt-blowing conditions include: a spinneret temperature of 200°C, a head pressure of 30bar, a stretching airflow pressure of 0.5bar, a side-blowing airflow temperature of 23°C, a roller pressure of 100daN / cm, a roller speed of 400m / min, a smooth roller pressure of 70daN / cm, and a smooth roller rolling speed of 600m / min Preparation of deformation-resistant and high dust-holding capacity filter bag material: inject the above-mentioned polypropylene into a screw extruder, melt-extrude it into a spinneret, and spray filaments from the head of the spinneret. The filaments are stretched into ultrafine fibers under the action of the airflow of the bellows. The fibers are compounded on the surface of the electrostatic filter layer after cold air heat exchange to form a deformation-resistant and high dust-holding capacity filter bag material. The melt-blowing conditions include: spinneret temperature 200°C, head pressure 18 bar, stretching airflow pressure 0.4 bar, side blowing airflow temperature 23°C, hot rolling roller temperature 130°C, hot rolling roller pressure 80 daN / cm, and hot rolling speed 600 m / min.

[0024] Embodiment 2: A method for preparing a deformation-resistant high-dust-holding filter bag material comprises the following steps: Preparation of hollow graphene spheres: 1 g of glucose, 5 g of polyvinyl alcohol, and 0.01 g of ferric chloride are added to 40 ml of deionized water and stirred to form a slurry, and the slurry is injected into a high-pressure reaction vessel for a first-stage calcination at a temperature of 100° C. for 24 hours. After the reaction vessel is cooled, the solid is separated; the solid is dried and placed in a microwave heating furnace for a second-stage calcination at a temperature of 400° C. for 20 minutes. After cooling, the solid is separated; the solid is placed in a tubular furnace and heated at 1000° C. for 2 hours under a nitrogen atmosphere. After cooling, the product is immersed in a hydrochloric acid solution (concentration 1 mol / L) for 12 hours, and after cleaning with deionized water and drying, the hollow graphene spheres (particle size of 3 to 15 nm) are obtained; Preparation of modified polypropylene: The prepared graphene hollow spheres are dispersed in a dispersion liquid (the mass ratio of dimethylformamide, sodium lignin sulfonate and sodium dodecylbenzene sulfonate is 1:0.01:0.05) to prepare a dispersion slurry, and then the polypropylene masterbatch is injected into a mixer, and the dispersion slurry is added from the side material port of the mixer (the graphene addition amount is 0.5%) and extruded to obtain modified polypropylene; the melt mixing conditions include: a feeding section temperature of 115°C, a conveying section temperature of 130°C, a melting section temperature of 140°C, and an extrusion section temperature of 145°C; Preparation of electrostatic filter layer: The electrostatic layer is ES hot air electrostatic cotton (20g / cm 2), putting polypropylene slices and polybutylene terephthalate slices into a drying oven for drying, injecting the dried polypropylene slices, polybutylene terephthalate and chlorinated biphenyl into a mixer for mixing to form a melt-blown non-woven polyester, injecting the melt-blown non-woven polyester slices into a screw extruder for melting and extrusion and injecting them into a spinneret, and spraying filaments from the head of the spinneret, and the filaments are stretched into ultrafine fibers under the action of the airflow of the bellows, and the fibers are compounded on the surface of the electrostatic layer after cold air heat exchange, and the electrostatic filter layer is formed by hot pressing with a flower roller and a flat roller, and the two layers of the electrostatic layer are respectively compounded with a layer of melt-blown non-woven fabric, and the melt-blowing conditions include: a spinneret temperature of 200°C, a head pressure of 33bar, a stretching airflow pressure of 0.6bar, a side-blowing airflow temperature of 24°C, a roller pressure of 105daN / cm, a roller speed of 450m / min, a smooth roller pressure of 75daN / cm, and a smooth roller rolling speed of 625m / min Preparation of deformation-resistant and high dust-holding capacity filter bag material: inject the above-mentioned polypropylene into a screw extruder, melt-extrude it into a spinneret, and spray filaments from the head of the spinneret. The filaments are stretched into ultrafine fibers under the action of the airflow of the bellows. The fibers are compounded on the surface of the electrostatic filter layer after cold air heat exchange to form a deformation-resistant and high dust-holding capacity filter bag material. The melt-blowing conditions include: spinneret temperature 200°C, head pressure 19 bar, stretching airflow pressure 0.43 bar, side blowing airflow temperature 24°C, hot rolling roller temperature 140°C, hot rolling roller pressure 85 daN / cm, and hot rolling speed 625 m / min.

[0025] Embodiment 3: A method for preparing a deformation-resistant high-dust-holding filter bag material comprises the following steps: Preparation of hollow graphene spheres: 1 g of glucose, 5 g of polyvinyl alcohol, and 0.01 g of ferric chloride are added to 40 ml of deionized water and stirred to form a slurry, and the slurry is injected into a high-pressure reaction vessel for a first calcination at a temperature of 140° C. for 10 hours. After the reaction vessel is cooled, the solid is separated; the solid is dried and placed in a microwave heating furnace for a second calcination at a temperature of 500° C. for 10 minutes. After cooling, the solid is separated; the solid is placed in a tubular furnace and heated at 1100° C. for 1 hour under a nitrogen atmosphere. After cooling, the product is immersed in a hydrochloric acid solution (concentration 1 mol / L) for 12 hours, and after being cleaned with deionized water and dried, the hollow graphene spheres (particle size of 3 to 15 nm) are obtained; Preparation of modified polypropylene: The prepared hollow graphene spheres are dispersed in a dispersion liquid (the mass ratio of dimethylformamide, sodium lignin sulfonate and sodium dodecylbenzene sulfonate is 1:0.01:0.05) to prepare a dispersion slurry, and then the polypropylene masterbatch is injected into a mixer, and the dispersion slurry is added from the side material port of the mixer (the graphene addition amount is 1%) to extrude to obtain modified polypropylene; the melt mixing conditions include: the feeding section temperature is 120°C, the conveying section temperature is 135°C, the melting section temperature is 145°C, and the extrusion section temperature is 150°C; Preparation of electrostatic filter layer: The electrostatic layer is ES hot air electrostatic cotton (20g / cm 2 ), putting polypropylene slices and polybutylene terephthalate slices into a drying oven for drying, injecting the dried polypropylene slices, polybutylene terephthalate and chlorinated biphenyl into a mixer for mixing to form a melt-blown non-woven polyester, injecting the melt-blown non-woven polyester slices into a screw extruder for melting and extrusion and injecting them into a spinneret, and spraying filaments from the head of the spinneret, and the filaments are stretched into ultra-fine fibers under the action of the airflow of the bellows, and the fibers are compounded on the surface of the electrostatic layer after cold air heat exchange, and the electrostatic filter layer is formed by hot pressing with a flower roller and a flat roller, and the two layers of the electrostatic layer are respectively compounded with a layer of melt-blown non-woven fabric, and the melt-blowing conditions include: a spinneret temperature of 180°C, a head pressure of 35bar, a stretching airflow pressure of 0.7bar, a side-blowing airflow temperature of 25°C, a roller pressure of 110daN / cm, a roller speed of 500m / min, a smooth roller pressure of 80daN / cm, and a smooth roller rolling speed of 650m / min Preparation of deformation-resistant and high dust-holding capacity filter bag material: inject the above-mentioned polypropylene into a screw extruder, melt-extrude it into a spinneret, and spray filaments from the head of the spinneret. The filaments are stretched into ultrafine fibers under the action of the airflow of the bellows. The fibers are compounded on the surface of the electrostatic filter layer after cold air heat exchange to form a deformation-resistant and high dust-holding capacity filter bag material. The melt-blowing conditions include: spinneret temperature 250°C, head pressure 20bar, stretching airflow pressure 0.45bar, side blowing airflow temperature 25°C, hot rolling roller temperature 145°C, hot rolling roller pressure 90daN / cm, and hot rolling speed 650m / min.

[0026] Embodiment 4: A method for preparing a deformation-resistant high-dust-holding filter bag material comprises the following steps: Preparation of hollow graphene spheres: 1 g of glucose, 5 g of polyvinyl alcohol, and 0.01 g of cobalt chloride are added to 40 ml of deionized water and stirred to form a slurry, and the slurry is injected into a high-pressure reaction vessel for a first calcination at a temperature of 220° C. for 12 hours, and after the reaction vessel is cooled, a solid is separated; the solid is dried and placed in a microwave heating furnace for a second calcination at a temperature of 500° C. for 2 minutes, and after cooling, a solid is separated; the solid is placed in a tubular furnace and heated at 1100° C. for 1 hour under a nitrogen atmosphere, and after cooling, the product is immersed in a hydrochloric acid solution (concentration 1 mol / L) for 12 hours, and after cleaning with deionized water and drying, a hollow graphene sphere (average particle size of 3 to 20 nm) is obtained; Preparation of modified polypropylene: The prepared graphene hollow spheres are dispersed in a dispersion liquid (dimethylformamide) to prepare a dispersion slurry, and then the polypropylene masterbatch is injected into a mixer, and the dispersion slurry is added from the side material port of the mixer (the graphene addition amount is 1%), and the modified polypropylene is extruded to obtain the modified polypropylene; the melt mixing conditions include: a feeding section temperature of 105°C, a conveying section temperature of 130°C, a melting section temperature of 140°C, and an extrusion section temperature of 145°C; Preparation of electrostatic filter layer: The electrostatic layer is ES hot air electrostatic cotton (20g / cm 2 ), putting polypropylene slices and polybutylene terephthalate slices into a drying oven for drying, injecting the dried polypropylene slices, polybutylene terephthalate and chlorinated biphenyl into a mixer for mixing to form a melt-blown non-woven polyester, injecting the melt-blown non-woven polyester slices into a screw extruder for melting and extrusion and injecting them into a spinneret, and spraying filaments from the head of the spinneret, and the filaments are stretched into ultra-fine fibers under the action of the airflow of the bellows, and the fibers are compounded on the surface of the electrostatic layer after cold air heat exchange, and the electrostatic filter layer is formed by hot pressing with a flower roller and a flat roller, and the two layers of the electrostatic layer are respectively compounded with a layer of melt-blown non-woven fabric, and the melt-blowing conditions include: a spinneret temperature of 200°C, a head pressure of 35bar, a stretching airflow pressure of 0.6bar, a side-blowing airflow temperature of 24°C, a roller pressure of 105daN / cm, a roller speed of 450m / min, a smooth roller pressure of 75daN / cm, and a smooth roller rolling speed of 600m / min Preparation of deformation-resistant and high dust-holding capacity filter bag material: inject the above-mentioned polypropylene into a screw extruder, melt-extrude it into a spinneret, and spray filaments from the head of the spinneret. The filaments are stretched into ultrafine fibers under the action of the airflow of the bellows. The fibers are compounded on the surface of the electrostatic filter layer after cold air heat exchange to form a deformation-resistant and high dust-holding capacity filter bag material. The melt-blowing conditions include: spinneret temperature 300°C, head pressure 20bar, stretching airflow pressure 0.45bar, side blowing airflow temperature 24°C, hot rolling roller temperature 140°C, hot rolling roller pressure 85daN / cm, and hot rolling speed 650m / min.

[0027] Embodiment 5: A method for preparing a deformation-resistant high-dust-holding filter bag material comprises the following steps: Preparation of hollow graphene spheres: 1 g of glucose, 5 g of polyvinyl alcohol, and 0.01 g of nickel chloride are added to 40 ml of deionized water and stirred to form a slurry, and the slurry is injected into a high-pressure reaction vessel for a first calcination at a temperature of 150° C. for 8 hours, and after the reaction vessel is cooled, a solid is separated; the solid is dried and placed in a microwave heating furnace for a second calcination at a temperature of 450° C. for 15 minutes, and after cooling, a solid is separated; the solid is placed in a tubular furnace and heated at 1100° C. for 1 hour under a nitrogen atmosphere, and after cooling, the product is immersed in a hydrochloric acid solution (concentration 1 mol / L) for 12 hours, and after cleaning with deionized water and drying, a hollow graphene sphere (average particle size of 3 to 18 nm) is obtained; Preparation of modified polypropylene: The prepared graphene hollow spheres are dispersed in a dispersion liquid to prepare a dispersion slurry (the mass ratio of sodium lignin sulfonate to sodium dodecylbenzene sulfonate is 1:5), and then the polypropylene masterbatch is injected into a mixer, and the dispersion slurry is added from the side material port of the mixer (the graphene addition amount is 1%) and extruded to obtain modified polypropylene; the melt mixing conditions include: a feeding section temperature of 120°C, a conveying section temperature of 130°C, a melting section temperature of 140°C, and an extrusion section temperature of 150°C; Preparation of electrostatic filter layer: The electrostatic layer is ES hot air electrostatic cotton (20g / cm 2 ), putting polypropylene slices and polybutylene terephthalate slices into a drying oven for drying, injecting the dried polypropylene slices, polybutylene terephthalate and chlorinated biphenyl into a mixer for mixing to form a melt-blown non-woven polyester, injecting the melt-blown non-woven polyester slices into a screw extruder for melting and extrusion and injecting them into a spinneret, and spraying filaments from the head of the spinneret, and the filaments are stretched into ultrafine fibers under the action of the airflow of the bellows, and the fibers are compounded on the surface of the electrostatic layer after cold air heat exchange, and the electrostatic filter layer is formed by hot pressing with a flower roller and a flat roller, and the two layers of the electrostatic layer are respectively compounded with a layer of melt-blown non-woven fabric, and the conditions for melt-blowing include: a spinneret temperature of 190°C, a head pressure of 33bar, a stretching airflow pressure of 0.6bar, a side-blowing airflow temperature of 24°C, a roller pressure of 100-110daN / cm, a roller speed of 450m / min, a smooth roller pressure of 80daN / cm, and a smooth roller rolling speed of 650m / min Preparation of deformation-resistant and high dust-holding capacity filter bag material: inject the above-mentioned polypropylene into a screw extruder, melt-extrude it into a spinneret, and spray filaments from the head of the spinneret. The filaments are stretched into ultrafine fibers under the action of the airflow of the bellows. The fibers are compounded on the surface of the electrostatic filter layer after cold air heat exchange to form a deformation-resistant and high dust-holding capacity filter bag material. The melt-blowing conditions include: spinneret temperature 250°C, head pressure 20bar, stretching airflow pressure 0.4bar, side blowing airflow temperature 25°C, hot rolling roller temperature 140°C, hot rolling roller pressure 85daN / cm, and hot rolling speed 625m / min.

[0028] Comparative Example 1: (No graphene hollow spheres were added to polypropylene, and the average wire diameter of the skeleton layer was 60 μm) Compared with Example 3, in Comparative Example 1, no hollow graphene spheres were added, the average fiber diameter of the skeleton layer was 60 μm, and the other conditions were the same as those in Example 3.

[0029] Comparative Example 2: (No graphene hollow spheres were added to polypropylene, and the diameter of the skeleton layer was 30 μm) Compared with Example 3, in Comparative Example 2, no graphene hollow spheres were added, the fiber diameter of the skeleton layer was 30 μm, and the other conditions were the same as those in Example 3.

[0030] Comparative Example 3: (Graphene replaces graphene hollow spheres) Compared with Example 3, graphene is used to replace the graphene hollow spheres in Comparative Example 3, and the other conditions are the same as those in Example 3.

[0031] Comparative Example 4: (Silicon dioxide replaces graphene hollow spheres) Compared with Example 3, in Comparative Example 4, silicon dioxide is used to replace the graphene hollow spheres, and the other conditions are the same as those in Example 3.

[0032] Test example: The performance of the filter materials prepared in the above-mentioned Examples 1 to 5 and Comparative Examples 1 to 3 was tested, and the test items included: stiffness, skeleton layer gram weight, filter material gram weight and average fiber diameter of the skeleton layer; The test method of stiffness refers to "GB / T 18318.1-2009 Textiles. Determination of bending properties. Part 6. Saddle method"; the test method of skeleton layer weight and filter material weight refers to "GB / T 24218-2010 Textile nonwoven fabric test plan"; The test method for the average fiber diameter of the skeleton layer refers to "GB / T 10685-2007 Test method for wool fiber diameter - projection microscope method"; The above test results are shown in Table 1; Table 1 Filter material performance test results As shown in Table 1, Examples 1 to 5 are filter materials prepared by the method for preparing deformation-resistant high dust holding capacity filter bag materials provided by the present invention. After testing, the rebound rate of the filter materials of Examples 1 to 5 is between 73.52% and 81.87%, and the weight of the skeleton layer is between 30 and 60 g / m 2 The average fiber diameter of the skeleton layer is 40-60 μm, and the dust holding capacity of the filter material is. The above results show that the filter material prepared by the method provided by the present invention has high stiffness, strong deformation resistance, light weight, high dust holding capacity and long service life.

[0033] Comparative Examples 1 and 2 are schemes in which polypropylene is modified without graphene hollow spheres. The average fiber diameter of the skeleton layer of Comparative Example 1 is 60 μm, and the average fiber diameter of the skeleton layer of Comparative Example 2 is 30 μm. From the results of Comparative Examples 1 and 2, when the average fiber diameter in Comparative Example 1 is 60 μm, the rebound rate of the filter material is 64.34%, while when the average fiber diameter in Comparative Example 2 is 30 μm, the rebound rate of the filter material is only 48.36%. It can be seen that the thickness of the average fiber diameter of the skeleton layer has an important influence on the filter material. The stiffness of the frame layer has a great influence. When the fiber diameter of the polypropylene material is below 30μm, the stiffness of the filter material is low and the material is relatively soft. When the fiber diameter of the polypropylene material exceeds 30μm, the stiffness of the filter material will increase, and the softness of the filter material is poor. In addition, after the fiber diameter increases, the gram weight of the filter layer will also increase significantly, the production cost increases and the overall weight of the filter material increases, which is not conducive to practical application. When the average fiber of the skeleton layer of the filter material prepared by the method provided by the present invention is 60μm, the gram weight is only 60g / m 2 The weight is significantly reduced, and the rebound rate of the filter material can reach 82.38%. The stiffness of the filter material is significantly improved. When the filter material is bent by external force, its resilience is significantly improved, which can significantly improve the deformation resistance of the filter bag during filtration.

[0034] In comparative example 3, ordinary graphene is used to replace the graphene hollow sphere. From the results of comparative example 3, it can be seen that the rebound rate of comparative example 3 is 68.31%, and the weight of the skeleton layer is 73g / m 2 It can be seen that although the use of graphene can increase the stiffness of the skeleton layer fibers, the effect is not as significant as that of using graphene hollow balls. The gram weight of the skeleton layer is also significantly higher than the technical method of using graphene hollow balls.

[0035] In Comparative Example 4, solid silicon dioxide is used to replace the graphene hollow spheres. From the results of Comparative Example 4, it can be seen that the rebound rate of Comparative Example 4 is 69.58%, and the weight of the skeleton layer is 100g / m 2 It can be seen that after using other solid fillers to modify polypropylene, the stiffness of the filter material can be significantly increased, but under the same fiber diameter, the gram weight of the skeleton layer increases extremely significantly, and the weight of the filter material increases significantly and cannot meet the use requirements.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a deformation-resistant high dust holding capacity filter bag material, characterized in that: The skeleton layer is processed by melt-blown composite to the surface of the electrostatic filter layer to form a deformation-resistant and high dust-holding capacity filter bag material. The skeleton layer is made of modified polypropylene, and the modified polypropylene is mixed with graphene hollow balls, dispersant and polypropylene as raw materials. The electrostatic filter layer is made of melt-blown non-woven fiber polyester that is processed by filtration melt-blown composite to the surface of both sides of the electrostatic cotton.

2. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The graphene hollow spheres are prepared by using a carbon source, a surfactant and a catalyst as raw materials through calcination and acid washing.

3. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 2, characterized in that: The carbon source is glucose; the surfactant is one or more of polyvinyl alcohol and polyethylene glycol; and the catalyst is one or more of nickel salt, cobalt salt and iron salt.

4. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The calcination process includes one-stage calcination, two-stage calcination and three-stage calcination.

5. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 4, characterized in that: The conditions of the first stage calcination include: temperature 100-160°C, time 5-24 hours; The conditions of the second stage calcination include: temperature 300-500°C, time 10-30 minutes; The conditions for the three-stage calcination include: nitrogen atmosphere, temperature 1000-1100° C., and time 1-2 hours.

6. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 4 or 5, characterized in that: The conditions for the three-stage calcination also include: nitrogen atmosphere.

7. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The dispersant is selected from one or more of dimethylformamide, sodium lignin sulfonate and sodium dodecylbenzene sulfonate; and the added amount of the modified hollow graphene spheres is 0.1-1%.

8. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The mixing conditions include: a feeding section temperature of 110-120°C, a conveying section temperature of 125-135°C, a melting section temperature of 135-145°C, and an extrusion section temperature of 140-150°C.

9. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The conditions of the skeleton melt-blown composite treatment include: a spinning temperature of 170-200°C, a die pressure of 18-20 bar, a stretching air flow pressure of 0.4-0.45 bar, a side-blowing air flow temperature of 23-25°C; a hot rolling roller temperature of 130-145°C, a hot rolling roller pressure of 80-90 daN / cm, and a hot rolling speed of 600-650 m / min.

10. The method for preparing a deformation-resistant high dust holding capacity filter bag material according to claim 1, characterized in that: The conditions of the filtration melt-blown composite treatment include: spinning temperature 200~300 ° C, head pressure 30~35 bar, stretching air flow pressure 0.5~0.7 bar, side blowing air flow temperature 23~25 ° C, roller pressure 100~110 daN / cm, roller speed 400~500 m / min, smooth roller pressure 70~80 daN / cm, smooth roller speed 600~650 m / min.

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