Disclosure of Invention
In order to solve the above problems, a first aspect of the present application provides a method for preparing a meltblown fabric with high filtering performance, comprising:
s1, processing a high molecular polymer in an extruder into a molten state under a high temperature condition;
s2, adjusting the relative positions of the melt-blowing die head and the rotary receiver to enable the angle of the melt-blowing die head to be 0-90 degrees and the receiving distance to be 11-25cm;
s3, spraying the high polymer in the molten state in the S1 through a melt-spraying die head to form fiber filaments, depositing the fiber filaments on the surface of a rotary receiver, and winding to obtain the fiber filaments.
In some preferred embodiments, the high molecular polymer in S1 is a thermoplastic polymer, which is not particularly limited herein.
Preferably, the high molecular polymer in the S1 is selected from one or more of polypropylene, polyethylene, ethylene copolymer, polylactic acid, polyurethane, polyethylene terephthalate, polycarbonate, polybutylene terephthalate and polyamide; further preferred is polypropylene.
In some preferred embodiments, the melt index of the high molecular polymer is not limited; preferably, the melt index of the high molecular polymer at 230 ℃/2.16kg is 800-2100g/10min; preferably 1550g/10min.
In some preferred embodiments, the high temperature conditions in S1 are 180-330 ℃, preferably 250-290 ℃.
In some preferred embodiments, the angle between the meltblowing die and the rotary receiver in S2 may be the angle in the X-axis direction or the angle in the Y-axis direction, which is not particularly limited in the present application.
Preferably, the angle between the melt-blowing die head and the rotary receiver in the step S2 is 30-60 degrees; further preferably 30-45 °; more preferably 45 °.
In the prior art, the melt-blown cloth mainly obtains better filtering performance by obtaining finer fibers and forming larger specific surface area, but the method can cause the problems of large increase of filtering resistance and low strength of the melt-blown cloth, and the melt-blown cloth cannot achieve higher filtering efficiency in the state of no increase of resistance. The inventors have found that by adjusting the angle of acceptance of the meltblown die head with the rotary receiver, the fibrous structure of the resulting meltblown fibers can be varied, and that when the angle of acceptance of the rotary receiver with the meltblown die head is from 0 to 90, a meltblown material having a three-dimensional structure can be obtained. Presumably, the reason is that after the receiving angle of the rotating receiver in the horizontal or vertical direction of the melt-blown filament bundle is changed, the stacking mode of the fibers is obviously changed, so that the fibers sprayed in the initial vertical direction are overlapped to a certain extent according to the adjustment of the receiving angle, and thus the fibers have a certain sense of three-dimension and layering, finally, the melt-blown material is changed from a two-dimensional structure to a three-dimensional structure, and the stacking density of the fibers is changed along with the change of the angle. Surprisingly, when the receiving angle of the melt-blowing die head and the rotary receiver is 30-60 degrees, the three-dimensional structure of the obtained material is obvious, the transverse distribution of fibers is more uniform and the material has excellent filtering performance under the condition of the same resistance by adjusting the synergistic effect of parameters such as spinning temperature, hot air temperature and air quantity, air conditioning cooling and the like.
In addition, in the prior art, the fineness of the fibers is mainly changed by the aperture and the number of holes of a melt-blowing die head used in the melt-spinning process, but the aperture and the number of holes are limited by processing materials and processing conditions, so that the fineness of the fibers and the bulk density of the melt-blown materials obtained by the prior art are also limited to a certain degree. And too fine pore diameter and too small pore spacing may easily cause problems such as inter-fiber adhesion phenomenon, poor fiber strength, etc., and compatibility between filtration efficiency and resistance cannot be balanced.
According to the application, through adjusting the change of the receiving angle of the melt-blowing die head and the rotary receiver, the stacking density, the transverse uniformity and the like of the fiber can be improved, and under the condition of the same fiber fineness, the formed three-dimensional structure has higher stacking density and specific surface area than a planar structure, so that a better filtering effect is achieved. In addition, the resistance value is reduced due to the change of the stacking mode, so that the expected performance of high efficiency and low resistance of the melt-blown material is realized, and the production difficulty and the manufacturing cost of the high efficiency and low resistance of the melt-blown material in the prior art are reduced.
In some preferred embodiments, the receiving distance is the perpendicular receiving distance between the meltblowing die and the rotating receiver.
In some preferred embodiments, preferably, the receiving distance in S2 is 13-17cm; further preferably 15cm.
In some preferred embodiments, the micropores in the meltblowing die in S2 have a pore size of 0.3 to 0.5mm and an aspect ratio of 11 to 15; preferably, the micropores have a pore size of 0.35mm and an aspect ratio of 13.
In some preferred embodiments, the flow rate of the high molecular polymer in the molten state in S3 is 50-60kg/h; preferably 55kg/h.
In some preferred embodiments, the temperature of the melt-blowing die in S3 is 240-385 ℃; preferably 260 ℃.
In some preferred embodiments, the polymer in the molten state in S3 needs to be stretched by hot air blowing when being ejected through a metering pump, so as to form filaments.
Preferably, the temperature of the hot air is 210-310 ℃ and the pressure is 0.7-1.2bar; further preferably, the temperature is 245-280℃and the pressure is 0.8-1.0bar; still more preferably, the temperature is 265℃and the pressure is 0.95bar.
In some preferred embodiments, the frequency of the rotating receiver in S3 is 7-16Hz; preferably 7-13Hz; more preferably 13Hz.
The rotary receiver is also provided with an air suction device for cooling the fiber yarns and improving the deposition effect of the fiber yarns on the rotary receiver.
In some preferred embodiments, the frequency of the suction device is 40-47Hz; preferably 43Hz.
The inventors found that in the present system, a suction device with a frequency of 40-47Hz and a rotating receiver with a frequency of 7-16Hz was used to facilitate smooth sagging of the meltblown fibers onto the rotating receiver surface. The possible reasons are presumed that in the process of extruding polypropylene fibers with a certain melt index into filaments, an air suction device with the frequency of 40-47Hz can cooperate with the drafting action of high-speed hot air flow to increase the traction force of the polypropylene fibers, so that the polypropylene fibers are smoothly adsorbed on the surface of a rotary receiver, the problems of flying, incapacity of depositing fibers, uneven fiber distribution and the like are avoided, meanwhile, the frequency of the rotary receiver is limited to 7-16Hz, the fluffiness of the obtained melt-blown fiber web is reduced, the porosity is reduced, the filtering efficiency is increased, and the filtering resistance is reduced. Surprisingly, the inventor finds that when the frequency of the air suction device is 43Hz and the frequency of the rotary receiver is 13Hz, under the synergistic effect of different specific parameters such as the included angle between the melt blowing die head and the rotary receiver, the sample injection amount of the metering pump, the temperature and pressure of high-speed hot air flow and the like, the wind power provided by the device is proper, the cooling and shaping speed of the melt blowing fiber net is further accelerated, the density of the melt blowing cloth is improved, the softness of the obtained melt blowing cloth is good, the tensile strength, the breaking elongation strength and the breaking elongation of the fiber are effectively improved, the mechanical property of the obtained melt blowing cloth is further improved, and the application range of the melt blowing cloth is expanded.
In a second aspect, the present application provides a high filtration performance meltblown web prepared by the above-described method.
In a third aspect, the present application provides the use of a high filtration performance meltblown web in an air purification material.
The civil filter material comprises an air purifying material and a cigarette filter tip.
Compared with the prior art, the application has the following beneficial effects:
(1) According to the application, the relative positions of the melt-blowing die head and the rotary receiver and other technological parameters are adjusted on the basis of the traditional melt-spinning technology, so that the fiber stacking mode and stacking density can be changed, the melt-blowing material with a three-dimensional result can be obtained, the specific surface area of the melt-blowing material is increased, the filtering effect is increased under the condition of the same resistance, the filtering efficiency and the resistance are well balanced, and the softness of the obtained melt-blowing material can be improved through parameter adjustment of the rotary receiver and the air suction device.
(2) According to the application, through adjusting the relative positions of the melt-blowing die head and the rotary receiver, the stacking angle of the fiber filaments on the surface of the rotary receiver is changed, so that the uniformity of transverse fibers of melt-blowing cloth is improved, the difference of transverse and longitudinal mechanical properties is reduced, the bonding strength of the fibers in the melt-blowing process is increased, the mechanical strength of the melt-blowing material is further increased, and the problem of filtration efficiency attenuation of the melt-blowing cloth is effectively alleviated.
(3) The preparation process of the melt-blown cloth with high filtering performance is simple, has low technical requirements on melt-blown equipment, is economical and feasible, and has wide application in the field of civil filtering materials, in particular to the field of air purifying materials.
Detailed Description
Example 1
1. A method of making a high filtration performance meltblown web comprising:
s1, processing a high molecular polymer in an extruder into a molten state under a high temperature condition;
s2, adjusting the relative position of the melt-blowing die head and the rotary receiver to enable the angle of the melt-blowing die head to be 45 degrees and the receiving distance to be 16cm;
s3, spraying the high polymer in the molten state in the S1 through a melt-spraying die head to form fiber filaments, depositing the fiber filaments on the surface of a rotary receiver, and winding to obtain the fiber filaments.
The high molecular polymer in the S1 is polypropylene.
The melt index of the high molecular polymer at 230 ℃/2.16kg is 1550g/10min (Dongguan city strong plastic raw materials Co., ltd., gold development technology Co., ltd.).
The high temperature condition in S1 is 260 ℃.
The angle between the melt blowing die head and the rotary receiver in the step S2 is the angle of the X-axis direction.
The receiving distance is the vertical receiving distance between the meltblowing die and the rotating receiver.
The aperture of the micropore in the melt-blowing die head in the step S2 is 0.35mm, and the length-diameter ratio is 13.
The flow rate of the high molecular polymer in the molten state in the step S3 is 55kg/h.
The temperature of the melt-blowing die in S3 was 260 ℃.
And (3) stretching the high polymer in the molten state in the step (S3) by blowing hot air when the high polymer is sprayed out by a metering pump, so as to form fiber yarns.
The temperature of the hot air was 265℃and the pressure was 0.95bar.
The frequency of the rotating receiver in the S3 is 13Hz.
The rotary receiver is also provided with an air suction device for cooling the fiber yarns and improving the deposition effect of the fiber yarns on the rotary receiver.
The frequency of the air suction device is 43Hz.
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Example 2
1. A method for preparing a meltblown web with high filtration performance, which differs from example 1 in that:
the angle between the melt blowing die head and the rotary receiver in the step S2 is the angle of the Y-axis direction.
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Example 3
1. A method for preparing a meltblown web with high filtration performance, which differs from example 1 in that:
the polypropylene had a melt index of 1800g/10min at 230℃C/2.16 kg (Korea Basel, brand MF 650Y).
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Example 4
1. A method for preparing a meltblown web with high filtration performance, which differs from example 1 in that:
the angle of the meltblowing die in S2 to the rotary receiver was 65 °.
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Example 5
1. A method for preparing a meltblown web with high filtration performance, which differs from example 1 in that:
the frequency of the rotating receiver in the S3 is 20Hz.
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Example 6
1. A method for preparing a meltblown web with high filtration performance, which differs from example 1 in that:
the frequency of the air suction device is 35Hz.
2. A high filtration performance meltblown web prepared by the above process.
3. The use of high filtration performance meltblown fabrics in household filtration materials.
Performance testing
1. PM2.5 filtration efficiency: the samples obtained in the examples were mounted on an air conditioner and tested according to the test method of GB/T34012-2017.
2. Filtration resistance: using an automatic filtration material efficiency detector (Model 8130, TSI) at a rated flow rate of 300m3 The pressure loss through the sample was determined under the conditions of/h.
3. Softness: test Standard GB/T8942-2016. The higher the softness value, the softer, and the better the hand feeling when the general softness is more than 20, and the requirements of general application can be satisfied (CN 202011606353.8).
Table 1 example performance test results