Heat-resistant high-molecular polypropylene filter material and preparation method thereof

Abstract

The invention discloses a heat-resistant high-molecular polypropylene filter material and a preparation method thereof, particularly relates to the technical field of high-molecular materials, and relates to a heat-resistant high-molecular polypropylene filter material and a preparation method thereof. The heat-resistant high-molecular polypropylene filter material is prepared from an inorganic filler, polypropylene resin, 4-methyl-1-pentene, an antioxidant, calcium stearate, dicumyl peroxide and 4-vinyl benzoic acid glycidyl ester. The invention discloses a polypropylene composite material which is prepared from the following raw materials in parts by weight: 0.8 to 1.5 parts of inorganic filler, 65 to 85 parts of polypropylene resin, 6 to 10 parts of 4-methyl-1-pentene, 0.1 to 0.3 part of antioxidant, 0.1 to 0.3 part of calcium stearate, 0.2 to 0.6 part of dicumyl peroxide and 1 to 5 parts of 4-vinyl benzoic acid glycidyl ester. The filter material is constructed by a preparation process of mixing the melt-blown fibers and the electrospun fibers, so that enough mechanical strength and stability are provided for the whole filter material, small particles can be efficiently intercepted, the filter precision is improved, and smooth transition among fibers with different sizes is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically, to a heat-resistant polymer polypropylene filter material and a preparation method thereof. Background Art

[0002] Filter materials are widely used in many fields such as chemical industry, food, medicine and environmental protection. Polypropylene has good chemical stability, mechanical properties and processing properties, and is widely used in the field of filter materials, becoming a commonly used filter material matrix. Therefore, the development of a new polypropylene filter material with excellent performance has important practical significance.

[0003] The polypropylene in the relevant technology includes propylene monomer, catalyst and additives; among them, propylene monomer is the basic raw material, which is connected through polymerization reaction to form long-chain macromolecules of polypropylene, which directly determines the chemical structure and basic properties of polypropylene and is the cornerstone of polypropylene materials; the catalyst is usually a Ziegler-Natta catalyst, whose function is to reduce the activation energy of the polymerization reaction, greatly accelerate the polymerization rate of propylene monomer, and enable the reaction to proceed under relatively mild conditions; it can accurately control the regularity of the polypropylene molecular chain, thereby affecting the key properties of polypropylene such as crystallization performance, melting point, and strength; additives include molecular weight regulators, antioxidants, and lubricants, which affect the mechanical properties of polypropylene.

[0004] However, it still has some shortcomings in actual use, such as poor heat resistance. The deformation temperature of polypropylene in related technologies is low. Under high temperature environment, the movement of molecular segments intensifies, and it is easy to soften, deform or even melt, resulting in poor shape and dimensional stability of the material; poor mechanical properties. High temperature will significantly weaken the mechanical properties of traditional polypropylene. Its mechanical indicators such as tensile strength and bending strength will obviously decrease under high temperature, making it easy to break and damage when subjected to certain external forces; low filtration efficiency. The surface and internal structure of traditional polypropylene are easily corroded in complex environments such as high temperature, high humidity and chemical media, resulting in changes in the filtration pore size, reduced filtration efficiency and difficulty in maintaining stability for a long time. Summary of the invention

[0005] In order to improve the above problems and reduce the problems of poor heat resistance, poor mechanical properties and low filtration efficiency of heat-resistant polymer polypropylene filter materials in the related art, the present invention specially provides a heat-resistant polymer polypropylene filter material and a preparation method thereof to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A heat-resistant high-molecular polypropylene filter material comprises the following steps:

[0008] A1, adding inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mixing for 10-20 minutes at a temperature of 60-80° C. and a rotation speed of 800-1200 r / min to obtain a mixed raw material;

[0009] A2, melt blending the mixed raw material obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: zone 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 220-230°C, during which the screw speed is controlled at 180-220r / min, and the feeding rate is 20-30kg / h; after melt blending, the mixed raw material is extruded and water-cooled to obtain modified polypropylene masterbatch;

[0010] A3, mixing the modified polypropylene masterbatch obtained in A2 with dicumyl peroxide in a low-speed mixer, mixing for 10-15 minutes at a temperature of 40-50° C. and a rotation speed of 30-50 r / min to obtain a mixed masterbatch;

[0011] A4, add the mixed masterbatch obtained in A3 to the melt-blowing equipment, set the melt-blowing die temperature to 230-240°C, the hot air temperature to 250-260°C, the hot air pressure to 0.2-0.3MPa, the receiving distance to 15cm, and prepare the melt-blown fiber layer to 0.2mm; then dissolve the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, and then load the solution into the electrospinning device, set the voltage to 18-22kV, the propulsion rate to 0.5-1.0mL / h, the receiving distance to 15cm, and prepare 300mm electrospun fiber layer; during the process, the relative positions of the electrospinning nozzle and the melt-blowing die head are adjusted so that the electrospun fibers fall on the intersection area of ​​the melt-blown fiber layer; then, the melt-blowing hot air pressure is reduced at a rate of 0.002MPa / min, the melt-blowing die head temperature is increased at a rate of 0.2℃ / min, the electrospinning propulsion is increased at a rate of 0.01mL / min, and the voltage is reduced at a rate of 0.1kV / min for 15min, and then maintained for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0012] A5, wavelength 2-5um, power density 3W / cm 2 The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then placed in an oven at a temperature of 180-200°C for drying for 30-60 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0013] Preferably, the components and parts by weight of the raw materials for preparing the heat-resistant polymer polypropylene filter material are as follows: 0.8 - 1.5 parts of inorganic filler, 65 - 85 parts of polypropylene resin, 6 - 10 parts of 4-methyl-1-pentene, 0.1 - 0.3 parts of antioxidant, 0.1 - 0.3 parts of calcium stearate, 0.2 - 0.6 parts of dicumyl peroxide, and 1 - 5 parts of glycidyl 4-vinylbenzoate.

[0014] Preferably, the inorganic filler is prepared from silane coupling agent KH-570 and boron nitride powder.

[0015] Preferably, the preparation of the inorganic filler includes the following steps:

[0016] C1. Place the silane coupling agent KH-570 in 10 - 20 times the volume of absolute ethanol, and then use a stirrer to stir at a speed of 200 - 300 r / min for 10 - 15 min to obtain a silane coupling agent solution;

[0017] C2. Put the boron nitride powder into an oven, dry it at a temperature of 100 - 120 °C for 2 - 3 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 500 - 800 r / min, and use a dropper to drop the silane coupling agent solution obtained in C1 into the mixer at a dropping speed of 2 drops / s. After dropping, continue to stir at a temperature of 80 - 100 °C for 30 - 60 min to obtain a mixed product;

[0018] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 60 - 80 °C for 6 - 8 h, then place it in a ball mill, ball mill it at a speed of 300 r / min for 3 h, and then select a 300-mesh sieve for sieving to obtain the inorganic filler.

[0019] Preferably, the components and parts by weight of the raw materials for preparing the inorganic filler are as follows: (0.5 - 5) parts of silane coupling agent KH-570 and 100 parts of boron nitride powder.

[0020] Preferably, the mixed solvent is composed of xylene and tetrahydrofuran with a volume ratio of 3:1.

[0021] Preferably, the antioxidant is antioxidant 1010.

[0022] The technical effects and advantages of the present invention:

[0023] 1. The present invention uses glycidyl 4-vinylbenzoate to carry out a copolymerization reaction with propylene, introducing epoxy groups into the polypropylene molecular chain, significantly improving the crosslinking ability of the material, and enhancing its heat resistance and the regularity of the molecular chain;

[0024] 2. The present invention introduces surface-functionalized nano-inorganic fillers, which are uniformly dispersed in the polypropylene matrix. By utilizing the high thermal conductivity and mechanical properties of boron nitride, the heat resistance and strength of the material are further improved, and the filtration performance is also enhanced.

[0025] 3. The present invention constructs a gradient structure through a special preparation process. The melt-blown fibers and electrospun fibers are mixed, which not only provides sufficient mechanical strength and stability for the entire filter material, but also can efficiently intercept fine particles, improve the filtration accuracy, and achieve a smooth transition between fibers of different scales. This ensures both the filtration efficiency and the air permeability, enabling the filter material to have different pore sizes and fiber densities at different levels, thus realizing an optimized combination of filtration accuracy and air permeability performance. Detailed Embodiments

[0026] The following further elaborates on the present invention in conjunction with the embodiments of the present invention. The raw materials used in the examples and embodiments of the present invention are all common commercially available materials, unless otherwise specifically stated below.

[0027] Preparation Examples 1 - 5

[0028] An inorganic filler, the preparation components and their corresponding ratios are shown in the following table, and it is prepared by the following preparation method:

[0029] C1. Place the silane coupling agent KH-570 in anhydrous ethanol with a volume 10 times that of the silane coupling agent, and then use a stirrer to stir at a speed of 200 r / min for 10 min to obtain a silane coupling agent solution.

[0030] C2. Put the boron nitride powder into an oven, dry it at a temperature of 100 °C for 2 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 500 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 dropwise into the mixer at a dropping rate of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 80 °C for 30 min to obtain a mixed product.

[0031] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 60 °C for 6 h, then place it in a ball mill, ball mill it at a speed of 300 r / min for 3 h, and then sieve it through a 300-mesh sieve to obtain the inorganic filler.

[0032] Table: Components and mass ratios (g) of the preparation raw materials in Preparation Examples 1 - 5

[0033]

[0034]

[0035] Preparation Example 6

[0036] An inorganic filler, which is different from Preparation Example 1, and the preparation method is as follows:

[0037] C1. Place the silane coupling agent KH-570 in anhydrous ethanol with a volume 10 times that of the silane coupling agent, and then use a stirrer to stir at a speed of 250 r / min for 12.5 min to obtain a silane coupling agent solution;

[0038] C2. Put the boron nitride powder into an oven, dry it at a temperature of 110 °C for 2.5 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 650 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 dropwise to the mixer at a dropping speed of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 90 °C for 45 min to obtain a mixed product;

[0039] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 70 °C for 7 h, then place it in a ball mill, ball mill it at a speed of 300 r / min for 3 h, and then select a sieve with a mesh size of 300 meshes for sieving to obtain the inorganic filler.

[0040] Preparation Example 7

[0041] An inorganic filler, which is different from Preparation Example 1, and the preparation method is as follows:

[0042] C1. Place the silane coupling agent KH-570 in anhydrous ethanol with a volume 10 times that of the silane coupling agent, and then use a stirrer to stir at a speed of 300 r / min for 15 min to obtain a silane coupling agent solution;

[0043] C2. Put the boron nitride powder into an oven, dry it at a temperature of 120 °C for 3 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 800 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 dropwise to the mixer at a dropping speed of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 100 °C for 60 min to obtain a mixed product;

[0044] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 80 °C for 8 h, then place it in a ball mill, ball mill it at a speed of 300 r / min for 3 h, and then select a sieve with a mesh size of 300 meshes for sieving to obtain the inorganic filler.

[0045] Preparation Example 8

[0046] An inorganic filler, which is different from Preparation Example 1, and the preparation method is as follows:

[0047] C1. Place the silane coupling agent KH-570 in 15 times its volume of absolute ethanol, and then use a stirrer to stir at a speed of 200 r / min for 10 min to obtain a silane coupling agent solution;

[0048] C2. Put the boron nitride powder into an oven, dry it at a temperature of 100 °C for 2 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 500 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 to the mixer at a dropping rate of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 80 °C for 30 min to obtain a mixed product;

[0049] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 60 °C for 6 h, then place it in a ball mill and ball mill it at a speed of 300 r / min for 3 h, and then select a 300-mesh sieve for sieving to obtain an inorganic filler.

[0050] Preparation Example 9

[0051] An inorganic filler, which is different from that of Preparation Example 1, and the preparation method is as follows:

[0052] C1. Place the silane coupling agent KH-570 in 20 times its volume of absolute ethanol, and then use a stirrer to stir at a speed of 200 r / min for 10 min to obtain a silane coupling agent solution;

[0053] C2. Put the boron nitride powder into an oven, dry it at a temperature of 100 °C for 2 h, then cool it to room temperature, transfer it to a high-speed mixer, then turn on the high-speed mixer, adjust the speed to 500 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 to the mixer at a dropping rate of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 80 °C for 30 min to obtain a mixed product;

[0054] C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 60 °C for 6 h, then place it in a ball mill and ball mill it at a speed of 300 r / min for 3 h, and then select a 300-mesh sieve for sieving to obtain an inorganic filler.

[0055] Preparation Examples 10 - 14

[0056] A heat-resistant polymer polypropylene filter material, the preparation components and their corresponding proportions are shown in the following table, and it is prepared by the following preparation method:

[0057] A1. Add inorganic filler, glycidyl 4-vinylbenzoate, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix them for 10 min at a temperature of 60 °C and a rotation speed of 800 r / min to obtain a mixed raw material;

[0058] wherein the inorganic filler is prepared in Preparation Example 1;

[0059] wherein the antioxidant is antioxidant 1010;

[0060] A2. Carry out melt blending on the mixed raw material obtained in A1 by a twin-screw extruder. The temperature settings of each section of the twin-screw extruder are as follows: the first zone is 180 °C, the second zone is 190 °C, the third zone is 200 °C, the fourth zone is 210 °C, and the die head is 220 °C. During this period, the screw rotation speed is controlled at 180 r / min, and the feeding speed is 30 kg / h; after melt blending, extrude, and cool with water to obtain a modified polypropylene masterbatch;

[0061] A3. Mix the modified polypropylene masterbatch obtained in A2 with dicumyl peroxide in a low-speed mixer, and mix them for 10 min at a temperature of 40 °C and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0062] A4. Add the mixed masterbatch obtained in A3 into a meltblowing device, set the meltblowing die head temperature at 230 °C, the hot air temperature at 250 °C, the hot air pressure at 0.2 MPa, and the receiving distance at 15 cm. When the meltblown fiber layer reaches 0.2 mm; then dissolve the mixed masterbatch in a mixed solvent to prepare a solution with a mass fraction of 10%, and then load the solution into an electrospinning device, set the voltage at 18 kV, the propulsion rate at 1.0 mL / h, and the receiving distance at 15 cm to prepare a 300 mm electrospun fiber layer; during this period, adjust the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fibers fall on the intersection area of the meltblown fiber layer; then adjust for 15 min under the conditions of a meltblowing hot air pressure reduction rate of 0.002 MPa / min, a meltblowing die head temperature increase rate of 0.2 °C / min, an electrospinning propulsion increase rate of 0.01 mL / min, and a voltage reduction rate of 0.1 kV / min, and then hold for 5 min. During this period, apply a directional electric field of 5 kV / m to obtain a filter material;

[0063] wherein the mixed solvent is composed of xylene and tetrahydrofuran with a volume ratio of 3:1;

[0064] A5. Use infrared radiation with a wavelength of 2 μm and a power density of 3 W / cm 2 to perform hot pressing and compounding on the filter material obtained in A4 at a pressure of 0.5 MPa and a temperature of 145 °C for 90 s, and then place it in an oven at a temperature of 180 °C and dry it for 30 min to obtain a heat-resistant polymer polypropylene filter material.

[0065] Table: Components and mass ratios of raw materials in Preparation Examples 10-14 (kg)

[0066]

[0067] Preparation Example 15

[0068] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0069] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 15 minutes at a temperature of 70° C. and a rotation speed of 1000 r / min to obtain a mixed raw material;

[0070] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0071] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0072] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0073] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0074] Preparation Example 16

[0075] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0076] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 20 minutes at a temperature of 80° C. and a rotation speed of 1200 r / min to obtain a mixed raw material;

[0077] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0078] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0079] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0080] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0081] Preparation Example 17

[0082] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0083] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0084] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: zone 1 185°C, zone 2 195°C, zone 3 205°C, zone 4 215°C, die head 225°C, during which the screw speed is controlled at 200r / min, and the feeding rate is 25kg / h; after melt blending, extrusion is carried out, and water cooling is performed to obtain modified polypropylene masterbatch;

[0085] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0086] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0087] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0088] Preparation Example 18

[0089] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0090] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0091] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 190°C in zone 1, 200°C in zone 2, 210°C in zone 3, 220°C in zone 4, and 230°C in die head, during which the screw speed is controlled at 220r / min, and the feeding rate is 20kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0092] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0093] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0094] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0095] Preparation Example 19

[0096] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0097] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0098] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0099] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 15 minutes at a temperature of 45° C. and a rotation speed of 40 r / min to obtain a mixed masterbatch;

[0100] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0101] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0102] Preparation Example 20

[0103] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0104] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0105] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0106] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 15 minutes at a temperature of 50° C. and a rotation speed of 50 r / min to obtain a mixed masterbatch;

[0107] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0108] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0109] Preparation Example 21

[0110] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0111] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0112] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0113] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0114] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 235°C, the hot air temperature to 255°C, the hot air pressure to 0.25MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 20kV, the propulsion rate to 0.75mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0115] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0116] Preparation Example 22

[0117] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0118] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0119] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0120] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0121] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 240°C, the hot air temperature to 260°C, the hot air pressure to 0.3MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 22kV, the propulsion rate to 0.5mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2℃ / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0122] A5, wavelength 2um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 180°C for 30 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0123] Preparation Example 23

[0124] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0125] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0126] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0127] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0128] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0129] A5, wavelength 3um, power density 3W / cm 2The filter material obtained by A4 was subjected to infrared radiation and hot-pressed for 90 seconds at a pressure of 0.5 MPa and a temperature of 145°C, and then dried in an oven at a temperature of 190°C for 45 minutes to obtain a heat-resistant high molecular weight polypropylene filter material.

[0130] Preparation Example 24

[0131] A heat-resistant high molecular weight polypropylene filter material, which is different from Preparation Example 10 in that the preparation method is as follows:

[0132] A1. Add inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mix for 10 minutes at a temperature of 60° C. and a rotation speed of 800 r / min to obtain a mixed raw material;

[0133] A2, melt blending the mixed raw materials obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, 210°C in zone 4, and 220°C in die head, during which the screw speed is controlled at 180r / min, and the feeding rate is 30kg / h; after melt blending, extrusion is performed, and water cooling is performed to obtain modified polypropylene masterbatch;

[0134] A3, the modified polypropylene masterbatch obtained in A2 and dicumyl peroxide were mixed in a low-speed mixer, and mixed for 10 minutes at a temperature of 40° C. and a rotation speed of 30 r / min to obtain a mixed masterbatch;

[0135] A4, adding the mixed masterbatch obtained in A3 to the meltblowing equipment, setting the meltblowing die temperature to 230°C, the hot air temperature to 250°C, the hot air pressure to 0.2MPa, and the receiving distance to 15cm, to prepare the meltblown fiber layer to 0.2mm; then dissolving the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, then loading the solution into the electrospinning device, setting the voltage to 18kV, the propulsion rate to 1.0mL / h, and the receiving distance to 15cm, to prepare a 300mm electrospun fiber layer; during the period, adjusting the relative position of the electrospinning nozzle and the meltblowing die head so that the electrospun fiber falls on the intersection area of ​​the meltblown fiber layer; then adjusting the meltblowing hot air pressure reduction rate to 0.002MPa / min, the meltblowing die temperature increase rate to 0.2°C / min, the electrospinning propulsion increase rate to 0.01mL / min, and the voltage reduction rate to 0.1kV / min for 15min, and then maintaining for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material;

[0136] A5, wavelength 5um, power density 3W / cm 2The infrared radiation was used to thermocompound the filter material obtained from A4 for 90 s under the conditions of a pressure of 0.5 MPa and a temperature of 145 °C, and then it was placed in an oven at 200 °C for drying for 60 min to obtain a heat-resistant polymer polypropylene filter material.

[0137] Preparation Examples 25 - 32

[0138] A heat-resistant polymer polypropylene filter material, which is different from that of Preparation Example 10 in that the usage of the inorganic filler used in its components is different, and the specific corresponding relationship is shown in the following table.

[0139] Table: Comparison Table of the Usage of Inorganic Fillers in Preparation Examples 25 - 32

[0140] Group Inorganic filler Preparation Example 25 Prepared from Preparation Example 2 Preparation Example 26 Prepared from Preparation Example 3 Preparation Example 27 Prepared from Preparation Example 4 Preparation Example 28 Prepared from Preparation Example 5 Preparation Example 29 Prepared from Preparation Example 6 Preparation Example 30 Prepared from Preparation Example 7 Preparation Example 31 Prepared from Preparation Example 8 Preparation Example 32 Prepared from Preparation Example 9

[0141] Performance Detection Test

[0142] The heat-resistant polymer polypropylene filter materials prepared in each of the examples were selected for inspection. The test subjects were 230 heat-resistant polymer polypropylene filter materials, with 10 in each group; their heat resistance, mechanical strength, and filtration performance were detected, and the specific detection steps were as follows:

[0143] Heat Resistance:

[0144] First, samples were taken from the heat-resistant polymer polypropylene filter materials prepared in the examples, and a heat distortion and Vicat temperature tester was used to detect their heat distortion temperature to characterize the heat resistance of the heat-resistant polymer polypropylene filter materials; the detection results and evaluation criteria are as follows:

[0145] Heat distortion temperature > 130 °C (regarded as strong heat resistance);

[0146] Heat distortion temperature < 130 °C (regarded as weak heat resistance).

[0147] Mechanical Strength:

[0148] First, samples were taken from the heat-resistant polymer polypropylene filter materials prepared in the examples, and an electronic universal testing machine was used to measure their breaking strength and calculate the elongation at break to characterize the mechanical strength of the heat-resistant polymer polypropylene filter materials; the detection results and evaluation criteria are as follows:

[0149] Breaking strength > 25 MPa, elongation at break > 300% (regarded as high mechanical strength);

[0150] Breaking strength < 25 MPa, elongation at break < 300% (regarded as low mechanical strength).

[0151] Filtration Performance:

[0152] Samples were first taken from the heat-resistant polymer polypropylene filter materials prepared in the examples. An aerosol generator was used to measure the concentrations of aerosol particles before and after the filter materials filtered aerosol particles with a particle size of 0.3 μm, and the filtration efficiency was calculated. A permeability tester was used to measure the volume of air passing through the test sample per unit time under 200 MPa for the filter materials to obtain the permeability; and the filtration performance of the heat-resistant polymer polypropylene filter materials was characterized based on this data. The test results and evaluation criteria are as follows:

[0153] Filtration efficiency > 99%, permeability > 200 L / (m 2 ·s) (regarded as strong filtration performance);

[0154] Filtration efficiency < 99%, permeability < 200 L / (m 2 ·s) (regarded as weak filtration performance).

[0155] It should be specifically noted that the above-prepared heat-resistant polymer polypropylene filter materials are heat-resistant polymer polypropylene filter materials produced by maintaining the normal production method. For defective heat-resistant polymer polypropylene filter materials produced, the data of such heat-resistant polymer polypropylene filter materials are discarded and not counted.

[0156] Examples 1-5

[0157] A heat-resistant polymer polypropylene filter material, and the corresponding relationships of the preparation methods used are shown in the following table.

[0158] Table: Comparison table of the usage of heat-resistant polymer polypropylene filter materials in Examples 1-5

[0159]

[0160]

[0161] The heat-resistant polymer polypropylene filter materials in Examples 1-5 above were extracted, and their heat distortion temperature, breaking strength, elongation at break, filtration efficiency, and permeability were tested according to the above measurement steps and measurement standards. The test results were averaged and recorded in the following table.

[0162] Table: Performance test results of heat distortion temperature, breaking strength, elongation at break, filtration efficiency, and permeability in Examples 1-5

[0163]

[0164] As can be seen from the above table, in the preparation process of the heat-resistant polymer polypropylene filter material in Examples 1-5, it has a good effect of improving the production effect of the heat-resistant polymer polypropylene filter material. Glycidyl 4-vinylbenzoate is used as a functional monomer to block copolymerize with propylene, introducing epoxy groups into the polypropylene molecular chain, significantly enhancing the cross-linking ability of the material, thereby enhancing the heat resistance and mechanical properties of the material. Adding boron nitride surface-modified with a silane coupling agent effectively improves its dispersibility in the polypropylene matrix. Utilizing the high thermal conductivity and mechanical properties of boron nitride, the heat resistance and strength of the material are further improved. The combination of melt-blown fibers and electrospun fibers not only provides sufficient mechanical strength and stability for the entire filter material, but also can efficiently intercept fine particles, improve the filtration accuracy, and achieve a smooth transition between fibers of different scales, ensuring both the filtration efficiency and the air permeability; thus achieving the purpose of improving the production effect of the heat-resistant polymer polypropylene filter material;

[0165] Its heat distortion temperature is 137.2-137.8 °C, which is regarded as having strong heat resistance; the breaking strength is 31.3-32.1 MPa, and the breaking elongation rate is 355.2-356.1%, which is regarded as having high mechanical strength; the filtration efficiency is 99.84-99.87%, and the air permeability is 256.0-256.5 L / (m 2 ·s), which is regarded as having strong filtration performance;

[0166] It can be seen that when the production raw materials are certain, the production effect of the heat-resistant polymer polypropylene filter material can be increased by adjusting the proportion of the preparation raw materials. Combining the data in the above table, it is not difficult to see that when preparing the heat-resistant polymer polypropylene filter material, the heat-resistant polymer polypropylene filter material prepared with 1.2 parts of inorganic filler, 75 parts of polypropylene resin, 8 parts of 4-methyl-1-pentene, 0.2 part of antioxidant, 0.2 part of calcium stearate, 0.4 part of diisopropylbenzene peroxide, and 3 parts of glycidyl 4-vinylbenzoate has the best heat resistance, mechanical strength, and filtration performance, which are obtained from Examples 1-5.

[0167] Examples 6-15

[0168] A heat-resistant polymer polypropylene filter material, and the corresponding relationship of its preparation method is shown in the following table.

[0169] Table: Comparison table of the usage of the heat-resistant polymer polypropylene filter material in Examples 6-15

[0170]

[0171]

[0172] Extract the heat-resistant polymer polypropylene filter materials in Examples 6-15 above, and test their heat distortion temperature, breaking strength, elongation at break, filtration efficiency, and air permeability according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0173] Table: Performance test results of heat distortion temperature, breaking strength, elongation at break, filtration efficiency, and air permeability of Examples 1, 6-15

[0174]

[0175] As can be seen from the above table, during the preparation of the heat-resistant polymer polypropylene filter materials in Examples 1, 6-11, they all have a good effect of improving the production effect of the heat-resistant polymer polypropylene filter materials. 4-Vinylbenzoic acid glycidyl ester is used as a functional monomer to block copolymerize with propylene, introducing epoxy groups into the polypropylene molecular chain, significantly enhancing the crosslinking ability of the material, thereby enhancing the heat resistance and mechanical properties of the material. Adding boron nitride surface-modified with a silane coupling agent effectively improves its dispersibility in the polypropylene matrix. Utilizing the high thermal conductivity and mechanical properties of boron nitride further enhances the heat resistance and strength of the material. The combination of melt-blown fibers and electrospun fibers not only provides sufficient mechanical strength and stability for the entire filter material but also can efficiently intercept fine particles, improving the filtration accuracy, achieving a smooth transition between fibers of different scales, ensuring both filtration efficiency and air permeability; thus achieving the purpose of improving the production effect of the heat-resistant polymer polypropylene filter materials;

[0176] Its heat distortion temperature is 137.2-137.8 °C, regarded as having strong heat resistance; the breaking strength is 31.3-31.9 MPa, and the elongation at break is 355.2-355.9%, regarded as having high mechanical strength; the filtration efficiency is 99.84-99.88%, and the air permeability is 256.1-256.7 L / (m 2 ·s), regarded as having strong filtration performance;

[0177] It can be seen that when the production raw materials are fixed, the production effect of the heat-resistant polymer polypropylene filter material can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the heat-resistant polymer polypropylene filter material, by increasing the temperature and rotation speed during the mixing process, the temperature and rotation speed during the melt blending process, reducing the feeding speed, increasing the temperature and pressure during the melt blowing process, the voltage during the electrospinning process, decreasing the propulsion rate, increasing the infrared radiation wavelength, the drying temperature and duration, the heat resistance, mechanical strength and filtration performance of the prepared heat-resistant polymer polypropylene filter material are all improved. The reason for this analysis is that the increase in the mixing temperature improves the molecular chain mobility, promotes the interfacial wetting between the nano-fillers and the resin, reduces the filler agglomeration, enhances the interfacial stress transfer, and thus improves the mechanical strength and heat resistance; the increase in the mixing rotation speed strengthens the shear force and accelerates the uniform dispersion of the components, especially the distribution of the cross-linking agent. The increase in the temperature during the melt blending process reduces the melt viscosity, promotes the grafting reaction between the comonomer and polypropylene, introduces more epoxy groups, enhances the cross-linking density, and at the same time improves the dispersion of the nano-fillers. The increase in the screw rotation speed increases the shear rate, refines the dispersed phase size, and forms a more uniform microstructure. The decrease in the feeding speed prolongs the residence time of the material in the extruder, promotes the chemical reaction and melt homogenization, reduces the residual unreacted monomers, and improves the thermal stability of the material. The increase in the melt blowing temperature and pressure reduces the melt viscosity, promotes the fiber refinement, optimizes the balance between the porosity of the support layer, air permeability and filtration efficiency; the increase in the electrospinning voltage enhances the electric field strength, refines the fiber diameter, and improves the interception efficiency. The decrease in the propulsion rate increases the stretching time of the solution in the electric field and reduces the fiber bead defect. The optimization of the infrared radiation wavelength promotes the molecular chain diffusion between adjacent layers and improves the interfacial bonding force. The increase in the drying temperature and the prolongation of the duration result in an increase in the cross-linking degree, as obtained from Examples 1, 8 - 15.

[0178] Examples 16 - 19

[0179] A heat-resistant polymer polypropylene filter material, and the corresponding relationships of its used preparation methods are shown in the following table.

[0180] Table: Comparative table of the usage of the heat-resistant polymer polypropylene filter material in Examples 16 - 19

[0181] Group Heat-resistant polymer polypropylene filter material Example 16 Prepared from Preparation Example 25 Example 17 Prepared from Preparation Example 26 Example 18 Prepared from Preparation Example 27 Example 19 Prepared from Preparation Example 28

[0182] Extract the heat-resistant polymer polypropylene filter materials in Examples 16 - 19 above, and test their heat distortion temperature, breaking strength, elongation at break, filtration efficiency and air permeability according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0183] Table: Performance test results of the heat distortion temperature, breaking strength, elongation at break, filtration efficiency and air permeability in Examples 1, 16 - 19

[0184]

[0185]

[0186] As can be seen from the above table, in the preparation process of the heat-resistant polymer polypropylene filter material in Examples 1, 16 - 19, it has a good effect of improving the production effect of the heat-resistant polymer polypropylene filter material. Glycidyl 4-vinylbenzoate is used as a functional monomer to block copolymerize with propylene, introducing epoxy groups into the polypropylene molecular chain, significantly enhancing the cross-linking ability of the material, thereby enhancing the heat resistance and mechanical properties of the material. Adding boron nitride surface-modified with a silane coupling agent effectively improves its dispersibility in the polypropylene matrix. Utilizing the high thermal conductivity and mechanical properties of boron nitride, the heat resistance and strength of the material are further improved. The melt-blown fibers and electrospun fibers are mixed, which not only provides sufficient mechanical strength and stability for the entire filter material, but also can efficiently intercept fine particles, improve the filtration accuracy, and achieve a smooth transition between fibers of different scales, ensuring both the filtration efficiency and the air permeability; thus achieving the purpose of improving the production effect of the heat-resistant polymer polypropylene filter material;

[0187] Its heat distortion temperature is 137.2 - 138.4 °C, regarded as having strong heat resistance; the breaking strength is 31.3 - 32.3 MPa, and the breaking elongation rate is 355.2 - 356.6%, regarded as having high mechanical strength; the filtration efficiency is 99.84 - 99.91%, and the air permeability is 256.1 - 257.4 L / (m 2 ·s), regarded as having strong filtration performance;

[0188] It can be seen that when the production raw materials are certain, the production effect of the heat-resistant polymer polypropylene filter material can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the inorganic filler, the inorganic filler prepared with 3 parts of silane coupling agent KH-570 and 100 parts of boron nitride powder has the best effect, and the heat resistance, mechanical strength, and filtration performance of the corresponding heat-resistant polymer polypropylene filter material are the highest. Analyzing the reason, silane coupling agent KH-570 has a special molecular structure. The alkoxy group at one end can hydrolyze to form silanol groups, which undergo a condensation reaction with the hydroxyl groups on the surface of the boron nitride powder to form stable chemical bonds. The polarity of the surface of the boron nitride powder changes, the surface energy decreases, and a steric hindrance effect is generated, preventing the agglomeration between boron nitride particles, and making boron nitride disperse in the polypropylene matrix in a relatively uniform state; obtained from Examples 1, 16 - 19.

[0189] Examples 20 - 23

[0190] A heat-resistant polymer polypropylene filter material, and the corresponding relationship of the preparation method used is shown in the following table.

[0191] Table: Comparative Table of the Usage of Heat-resistant Polypropylene Filter Materials in Examples 20 - 23

[0192] Group Heat-resistant polymer polypropylene filter material Example 20 Prepared from Preparation Example 29 Example 21 Prepared from Preparation Example 30 Example 22 Prepared from Preparation Example 31 Example 23 Prepared from Preparation Example 32

[0193] Extract the heat-resistant polypropylene filter materials in Examples 20 - 23 above, and test their heat distortion temperature, breaking strength, elongation at break, filtration efficiency, and air permeability according to the above measurement steps and measurement standards. The test results are averaged and recorded in the following table.

[0194] Table: Performance Test Results of Heat Distortion Temperature, Breaking Strength, Elongation at Break, Filtration Efficiency, and Air Permeability in Examples 1, 20 - 23

[0195]

[0196]

[0197] As can be seen from the above table, during the preparation of the heat-resistant polypropylene filter materials in Examples 1, 20 - 23, they all have a good effect of improving the production effect of the heat-resistant polypropylene filter materials. Glycidyl 4-vinylbenzoate is used as a functional monomer to block copolymerize with propylene, introducing epoxy groups into the polypropylene molecular chain, significantly enhancing the cross-linking ability of the material, thereby enhancing the heat resistance and mechanical properties of the material. Adding boron nitride surface-modified with a silane coupling agent effectively improves its dispersion in the polypropylene matrix. Utilizing the high thermal conductivity and mechanical properties of boron nitride, the heat resistance and strength of the material are further improved. The melt-blown fibers and electrospun fibers are mixed, which not only provides sufficient mechanical strength and stability for the entire filter material, but also can efficiently intercept fine particles, improve the filtration accuracy, and achieve a smooth transition between fibers of different scales, ensuring both the filtration efficiency and the air permeability; thus achieving the purpose of improving the production effect of the heat-resistant polypropylene filter materials;

[0198] Its heat distortion temperature is 137.2 - 138.4 °C, regarded as having strong heat resistance; the breaking strength is 31.3 - 32.3 MPa, the elongation at break is 355.2 - 356.6%, regarded as having high mechanical strength; the filtration efficiency is 99.84 - 99.91%, and the air permeability is 256.1 - 257.4 L / (m 2 ·s), regarded as having strong filtration performance;

[0199] It can be seen that when the production raw materials are fixed, the production effect of the heat-resistant polymer polypropylene filter material can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the inorganic filler, by increasing the rotation speed, stirring duration during the preparation process of the silane coupling agent solution, increasing the drying temperature and duration of the boron nitride powder, and increasing the rotation speed, temperature, and duration during the mixing process, the heat resistance, mechanical strength, and filtration performance of the corresponding heat-resistant polymer polypropylene filter material are all improved. The reason for this is that a higher rotation speed and a longer stirring duration can enable the silane coupling agent to be fully dispersed in the solvent. Under rapid stirring, the silane coupling agent molecules are more evenly distributed in the solvent system, avoiding situations of too high or too low local concentration. Appropriately increasing the rotation speed and stirring duration is conducive to the hydrolysis reaction, enabling more silane coupling agents to be converted into the active silanol form, thereby enhancing the binding ability with boron nitride. Increasing the drying temperature and prolonging the drying duration can more effectively remove the moisture on the surface of boron nitride, enabling the silane coupling agent to better undergo chemical bonding with the active sites on the surface of boron nitride during subsequent treatment, enhancing the interfacial binding force. Appropriate high-temperature drying can make the crystal structure of boron nitride more stable. A higher rotation speed and a longer mixing duration can enable the modified boron nitride powder to be fully mixed with the silane coupling agent solution, further ensuring that the silane coupling agent is evenly coated on the surface of boron nitride. Increasing the mixing temperature can accelerate the chemical reaction rate, promote the chemical bonding between the silane coupling agent and boron nitride, as well as between the modified boron nitride and the polypropylene matrix, improve the molecular chain movement, optimize the pore structure of the filter material, and improve the filtration performance. Obtained from Examples 1, 20 - 21.

[0200] It can be seen that when the production raw materials are fixed, the production effect of the heat-resistant polymer polypropylene filter material can be increased by adjusting the preparation conditions. Combining the data in the above table, it is not difficult to see that when preparing the inorganic filler, by decreasing the volume ratio of the silane coupling agent solution, the changes in the heat resistance, mechanical strength, and filtration performance of the corresponding heat-resistant polymer polypropylene filter material are not significant. Obtained from Examples 1, 22 - 23.

[0201] This specific embodiment is only an explanation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A preparation method of a heat-resistant polymer polypropylene filter material, characterized in that, The following steps are involved: A1, adding inorganic filler, 4-vinyl benzoic acid glycidyl ester, polypropylene resin, 4-methyl-1-pentene, antioxidant and calcium stearate into a high-speed mixer, and mixing for 10-20 minutes at a temperature of 60-80° C. and a rotation speed of 800-1200 r / min to obtain a mixed raw material; A2, melt blending the mixed raw material obtained in A1 through a twin-screw extruder, the temperature of each section of the twin-screw extruder is set as follows: zone 1 180-190°C, zone 2 190-200°C, zone 3 200-210°C, zone 4 210-220°C, die head 220-230°C, during which the screw speed is controlled at 180-220r / min, and the feeding rate is 20-30kg / h; after melt blending, the mixed raw material is extruded and water-cooled to obtain modified polypropylene masterbatch; A3, mixing the modified polypropylene masterbatch obtained in A2 with dicumyl peroxide in a low-speed mixer, mixing for 10-15 minutes at a temperature of 40-50° C. and a rotation speed of 30-50 r / min to obtain a mixed masterbatch; A4, add the mixed masterbatch obtained in A3 to the melt-blowing equipment, set the melt-blowing die temperature to 230-240°C, the hot air temperature to 250-260°C, the hot air pressure to 0.2-0.3MPa, the receiving distance to 15cm, and prepare the melt-blown fiber layer to 0.2mm; then dissolve the mixed masterbatch in the mixed solvent to prepare a solution with a mass fraction of 10%, and then load the solution into the electrospinning device, set the voltage to 18-22kV, the propulsion rate to 0.5-1.0mL / h, the receiving distance to 15cm, and prepare 300mm electrospun fiber layer; during the process, the relative positions of the electrospinning nozzle and the melt-blowing die head are adjusted so that the electrospun fibers fall on the intersection area of ​​the melt-blown fiber layer; then, the melt-blowing hot air pressure is reduced at a rate of 0.002MPa / min, the melt-blowing die head temperature is increased at a rate of 0.2℃ / min, the electrospinning propulsion is increased at a rate of 0.01mL / min, and the voltage is reduced at a rate of 0.1kV / min for 15min, and then maintained for 5min, during which a directional electric field of 5kV / m is applied to obtain a filter material; A5. Using an infrared radiation with a wavelength of 2 - 5 μm and a power density of 3 W / cm 2 The filter material obtained in A4 is hot - pressed and compounded for 90 s under a pressure of 0.5 MPa and a temperature of 145 °C using the infrared radiation, and then placed in an oven at a temperature of 180 - 200 °C for drying for 30 - 60 min to obtain a heat - resistant polymer polypropylene filter material.

2. The preparation method of a heat-resistant polymer polypropylene filter material according to claim 1, characterized in that: The raw material components and weight proportions of the heat-resistant high molecular weight polypropylene filter material are as follows: 0.8-1.5 parts of inorganic filler, 65-85 parts of polypropylene resin, 6-10 parts of 4-methyl-1-pentene, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of calcium stearate, 0.2-0.6 parts of dicumyl peroxide, and 1-5 parts of 4-vinyl benzoic acid glycidyl ester.

3. The preparation method of a heat-resistant polymer polypropylene filter material according to claim 1, characterized in that: The inorganic filler is prepared from silane coupling agent KH-570 and boron nitride powder.

4. The preparation method of a heat-resistant polymer polypropylene filter material according to claim 1, characterized in that: The inorganic filler comprises the following preparation steps: C1. Place silane coupling agent KH-570 in 10-20 times volume of anhydrous ethanol, and then stir with a stirrer at a speed of 200-300 r / min for 10-15 min to obtain a silane coupling agent solution; C2. Put the boron nitride powder into an oven, dry it at a temperature of 100 - 120 °C for 2 - 3 h, then cool it to room temperature, transfer it to a high-speed mixer. Then turn on the high-speed mixer, adjust the rotation speed to 500 - 800 r / min, and use a dropper to add the silane coupling agent solution obtained in C1 into the mixer at a dropping rate of 2 drops / s. After the dropping is completed, continue to stir at a temperature of 80 - 100 °C for 30 - 60 min to obtain a mixed product; C3. Transfer the mixed product obtained in C2 to a vacuum drying oven, dry it at a temperature of 60 - 80 °C for 6 - 8 h, then place it in a ball mill and ball mill it at a rotation speed of 300 r / min for 3 h. Then select a 300-mesh sieve for sieving to obtain an inorganic filler.

5. A heat-resistant polymer polypropylene filter material formulation according to claim 1, characterized in that: The components and weight parts of each raw material for preparing the inorganic filler are as follows: Silane coupling agent KH-570 (0.5 - 5) parts, 100 parts of boron nitride powder.

6. The preparation method of a heat-resistant polymer polypropylene filter material according to claim 1, characterized in that: The mixed solvent is composed of xylene and tetrahydrofuran with a volume ratio of 3:

1.

7. The preparation method of a heat-resistant polymer polypropylene filter material according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

8. A heat-resistant polymer polypropylene filter material prepared by the preparation method according to any one of claims 1 - 7.

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