阅读说明：本技术 喷吹负载微纳米粒子的自充电无纺布及其制备方法和应用 (Self-charging non-woven fabric for blowing loaded micro-nano particles and preparation method and application thereof ) 是由 王亚飞 吴龙涛 朴一镛 宋宝祥 刘欣 吴子航 陈凯 于 2019-09-29 设计创作，主要内容包括：本发明提供了一种喷吹负载微纳米粒子的自充电无纺布及其制备方法和应用,通过在常规熔喷加工的气流中添加具有高介电常数差的微纳米粒子,在气流的喷吹作用下使其负载于聚合物熔体纤维表面,制得自充电无纺布。在气流吹扫的作用下,具有高介电常数差的微纳米粒子通过摩擦起电,实现静电荷的存储。将本发明制备的自充电无纺布应用于空气过滤材料,其过滤效率≥99.5％,过滤阻力≤30Pa；在空气流通的情况下,具有高介电常数差的微纳米粒子能够与周围聚合物纤维进行反复接触与分离,不断产生静电荷,从而提高过滤材料静电性能的持久性,有效解决了电荷易衰减的问题。(The invention provides a self-charging non-woven fabric loaded with micro-nano particles by blowing, and a preparation method and application thereof. Under the action of air flow purging, the micro-nano particles with high dielectric constant difference are electrified through friction, and static charge storage is realized. The self-charging non-woven fabric prepared by the invention is applied to an air filtering material, the filtering efficiency is more than or equal to 99.5 percent, and the filtering resistance is less than or equal to 30 Pa; under the condition of air circulation, the micro-nano particles with high dielectric constant difference can be repeatedly contacted and separated with surrounding polymer fibers to continuously generate static charges, so that the durability of the electrostatic performance of the filter material is improved, and the problem that the charges are easy to attenuate is effectively solved.)

1. The utility model provides a blowing load micro-nano particle's self-charging non-woven fabrics which characterized in that includes: the polymer fiber and the micro-nano particles with high dielectric constant difference loaded on the surface of the polymer fiber are sprayed and loaded on the surface of the polymer fiber through melt-blown airflow, and generate electret charges through the friction and electrification action of the polymer fiber.

2. The blowing-loaded micro-nano particle self-charging non-woven fabric of claim 1, wherein the micro-nano particles with high dielectric constant difference have a particle size of 1 μm or less, and the loading amount is 3-12 wt% of the mass of the polymer fiber.

3. The self-charging non-woven fabric loaded with micro-nano particles by blowing according to claim 2, wherein the polymer fibers are polypropylene fibers, polyethylene fibers or polyester fibers; the micro-nano particles with the high dielectric constant difference are one or two of polytetrafluoroethylene micro-nano particles, wool micro-nano particles or fluorinated ethylene propylene micro-nano particles.

4. The preparation method of the blowing micro-nano particle loaded self-charging non-woven fabric according to any one of claims 1 to 3, characterized by comprising the following steps:

s1, melting the dried polymer spinning raw material in a screw extruder, and then spraying the melted polymer spinning raw material from a spinneret orifice to perform melt spinning;

s2, blowing the polymer melt fiber by adopting the melt-blown airflow dispersed with the micro-nano particles with high dielectric constant difference to obtain the polymer fiber loaded with the micro-nano particles with high dielectric constant difference on the surface;

and S3, laying the polymer fibers into a net through a receiving device, and then performing electret treatment to obtain the self-charging non-woven fabric loaded with the micro-nano particles by blowing.

5. The method for preparing the self-charging non-woven fabric loaded with the micro-nano particles by blowing according to claim 4, wherein in the step S1, the receiving distance of the melt spinning is 8-30 cm, and the diameter of the spinning hole is 0.1-1 mm.

6. The method for preparing the self-charging non-woven fabric loaded with the micro-nano particles by blowing according to claim 4, wherein in step S2, the temperature of the melt-blown airflow is 280-320 ℃, the flow rate of the melt-blown airflow is 300-500 m/S, and the ejection volume of the micro-nano particles with the high dielectric constant difference is 30-80 mg/S.

7. The method for preparing the self-charging non-woven fabric loaded with micro-nano particles by blowing according to claim 4, wherein in step S3, the electret treatment is corona discharge electret treatment.

8. The use of the blowing micro-nano particle loaded self-charging non-woven fabric according to any one of claims 1 to 3 or the self-charging non-woven fabric prepared by the method according to any one of claims 4 to 7, wherein the blowing micro-nano particle loaded self-charging non-woven fabric is used for preparing an air filter material.

9. The application of the self-charging non-woven fabric for blowing the loaded micro-nano particles as claimed in claim 8, wherein the filtering efficiency of the air filtering material is more than or equal to 99.5%, the filtering resistance is less than or equal to 30Pa, the surface electrostatic voltage is more than or equal to 3kV, and the electrostatic voltage after the air filtering material is placed for 4 months is more than or equal to 2.8 kV.

Technical Field

The invention belongs to the technical field of air filtering materials, and particularly relates to a blowing micro-nano particle loaded self-charging non-woven fabric, and a preparation method and application thereof.

Background

Due to the unique structural form of the fiber filter material, the fiber filter material becomes one of the main driving forces for the development of the filter technology. Compared with other filtering technologies, the fiber filtering technology has the advantages of high controllability of fiber diameter/pore size, high porosity, controllable stacking form, high environmental adaptability and the like, so that the fiber filtering technology has excellent filtering performance. The fiber air filtration is a process for separating dust particles suspended in air, and the filtration mechanism mainly comprises the following steps: gravity effects, inertial effects, interception effects, diffusion effects, and electrostatic effects. The electrostatic interaction can obviously improve the combination condition between particles and filter medium fibers, and mainly shows that the electrostatic interaction drives the streamline track of the particles to change and deposit the particles, and the electrostatic interaction makes the particles adsorbed on the surface of the filter medium fibers more stably, so that the secondary shedding of particle pollutants under the condition of higher filter wind speed is obviously improved, and the filter performance of the filter medium is effectively improved. For example, the electret fiber can directly adsorb and capture charged or neutral particles in air by means of electrostatic force, so that the filtering efficiency is improved while the air resistance is not increased. Electret fiber materials therefore constitute the most promising filter materials.

Currently, most organic electrets are high-insulating fluoropolymers such as Polytetrafluoroethylene (PTFE), fluorinated ethylene Propylene (PVDF), and the like. Among them, PTFE is an organic electret material with excellent properties due to its characteristics such as dielectric properties, low dielectric loss, high breakdown voltage, and high volume resistivity. However, since PTFE cannot be dissolved by a general method, it cannot be produced by a solution spinning method; because the melt viscosity of PTFE is very high (1010 to 1012 Pa.s at 350 ℃), the PTFE will not be converted into viscous state when heated to 415 ℃, and only gel without crystal is formed, so that the PTFE is difficult to be formed, and cannot be processed and formed by a melt spinning method. Therefore, in the prior art, the PTFE fine powder is mainly dispersed in the spinning solution to be spun, and there are problems of poor electrostatic durability and reduced mechanical properties. In addition, the prepared nonwoven material usually needs post-treatment means such as applying strong external electric field to polarize the electret material, and then removing the electric field to store charges on the surface or inside of the dielectric.

For example, the invention patent with the application number of CN201610803294.0 discloses a polytetrafluoroethylene-polypropylene composite electret air filter material, which is prepared by adding a mixture of silicon nanowires, polytetrafluoroethylene suspended fine powder and sodium chloride and polypropylene into a double-screw compounding extruder for melt extrusion to prepare polypropylene composite master batches, and then carrying out melt-blown spinning and corona discharge electret treatment to obtain the polytetrafluoroethylene-polypropylene composite electret air filter material, wherein the filtration efficiency of the material reaches 99.98%, but the filtration resistance reaches 88.92Pa, and the preparation method is complicated, high in production cost and not suitable for large-scale production.

Therefore, it is urgently needed to develop a novel electret filter material with high efficiency, low resistance, high surface potential and good charge stability.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a self-charging non-woven fabric loaded with micro-nano particles by blowing and a preparation method and application thereof, wherein the micro-nano particles with high dielectric constant difference are added into air flow of conventional melt-blowing processing, and the micro-nano particles with high dielectric constant difference are loaded on the surface of a polymer melt fiber by utilizing the blowing action of the air flow, so that electret charges can be generated by the friction electrification action with the fiber; and under the condition of air circulation, the particles with high dielectric constant difference can be repeatedly contacted and separated with the surrounding polymer fibers to continuously generate static charges, so that the durability of the static performance is improved, and the problem that the charges are easy to attenuate is effectively solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a blowing loaded micro-nano particle self-charging non-woven fabric comprises: the polymer fiber and the micro-nano particles with high dielectric constant difference loaded on the surface of the polymer fiber are sprayed and loaded on the surface of the polymer fiber through melt-blown airflow, and generate electret charges through the friction and electrification action of the polymer fiber.

Furthermore, the particle size of the micro-nano particles with high dielectric constant difference is less than or equal to 1 mu m, and the load is 3-12 wt% of the mass of the polymer fiber.

Further, the polymer fiber is polypropylene fiber, polyethylene fiber or polyester fiber; the micro-nano particles with the high dielectric constant difference are one or two of polytetrafluoroethylene micro-nano particles, wool micro-nano particles or fluorinated ethylene propylene micro-nano particles.

The preparation method of the self-charging non-woven fabric loaded with the micro-nano particles by blowing is characterized by comprising the following steps of:

s1, melting the dried polymer spinning raw material in a screw extruder, and then spraying the melted polymer spinning raw material from a spinneret orifice to perform melt spinning;

s2, blowing the polymer melt fiber by adopting the melt-blown airflow dispersed with the micro-nano particles with high dielectric constant difference to obtain the polymer fiber loaded with the micro-nano particles with high dielectric constant difference on the surface;

and S3, laying the polymer fibers into a net through a receiving device, and then performing electret treatment to obtain the self-charging non-woven fabric loaded with the micro-nano particles by blowing.

Further, in step S1, the receiving distance of the melt spinning is 8 to 30cm, and the diameter of the spinneret hole is 0.1 to 1 mm.

Further, in step S2, the temperature of the melt-blown airflow is 280 to 320 ℃, the flow rate of the melt-blown airflow is 300 to 500m/S, and the ejection amount of the micro-nano particles with high dielectric constant difference is 30 to 80 mg/S.

Further, in step S3, the electret treatment is corona discharge electret treatment.

The self-charging non-woven fabric for blowing and loading the micro-nano particles or the self-charging non-woven fabric prepared by the method is applied to the preparation of the air filtering material.

Furthermore, the filtering efficiency of the air filtering material is more than or equal to 99.5%, the filtering resistance is less than or equal to 30Pa, the surface electrostatic voltage is more than or equal to 3kV, and the electrostatic voltage after being placed for 4 months is more than or equal to 2.8 kV.

Advantageous effects

Compared with the prior art, the self-charging non-woven fabric loaded with micro-nano particles by blowing, the preparation method and the application thereof have the following beneficial effects:

(1) the invention provides a blowing micro-nano particle loaded self-charging non-woven fabric, which consists of polymer fibers and micro-nano particles loaded on the surfaces of the polymer fibers and having high dielectric constant difference. In the traditional method, the micro-nano particles with high dielectric constant difference are dispersed in the spinning solution to carry out solution spinning, if the addition amount is too large, the spinning performance of the spinning solution can be influenced, and further the mechanical property, the air permeability and the like of the polymer fiber are influenced, so that excellent comprehensive performance is difficult to realize.

(2) According to the preparation method of the self-charging non-woven fabric loaded with the micro-nano particles by blowing, under the blowing action of air flow, the micro-nano particles with high dielectric constant difference are sprayed and loaded on the surface of the polymer melt fiber, and in the process, the micro-nano particles with high dielectric constant difference and the polymer fiber can generate friction electrification, so that static charge is stored, and electret charge can be generated through the friction electrification with the fiber; in addition, the non-woven fabric storing positive charges or negative charges can be prepared by adjusting the types of the micro-nano particles with high dielectric constant difference and the polymer fibers according to the requirements of customers. Compared with the traditional method, the electrostatic charge storage capacity is higher, so that the electrostatic voltage is higher.

(3) According to the invention, by reasonably regulating and controlling the melt temperature, the temperature and the speed of the blowing air flow, the injection speed of the micro-nano particles with high dielectric constant difference and the like, single-layer or multi-layer micro-nano particles with high dielectric constant difference can be accurately loaded on the surface of the fiber melt, so that the electrostatic adsorption performance of the non-woven fabric can be accurately regulated and controlled.

(4) The self-charging non-woven fabric for blowing and loading micro-nano particles can be applied to an air filtering material, the filtering efficiency is more than or equal to 99.5%, and the filtering resistance is less than or equal to 30 Pa; under the condition of air circulation, the particles with high dielectric constant difference can be repeatedly contacted and separated with the surrounding polymer fibers to continuously generate static charges, so that the durability of the static performance is improved, and the problem that the charges are easy to attenuate is effectively solved.

Drawings

FIG. 1 is a schematic diagram of the principle of the present invention for online spraying loaded micro-nano particles;

fig. 2 is a scanning electron microscope image of the polypropylene fiber self-charging non-woven fabric with the surface loaded with the polytetrafluoroethylene micro-nanoparticles prepared in example 1.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

The invention provides a self-charging non-woven fabric for blowing and loading micro-nano particles, which is based on the air spraying principle, and is characterized in that in the melt spinning process, blowing and stretching are generally carried out by using melt-blown airflow, and in the stretching process, fibers are gradually cooled and solidified into fiber filaments from a melt state, so that high-speed airflow containing the micro-nano particles with high dielectric constant difference is used for blowing, and the micro-nano particles with high dielectric constant difference can be successfully loaded on the surfaces of the fibers through hydrodynamics, temperature control and regulation and control of specific surface energy of the melt.

Referring to fig. 1, the self-charging non-woven fabric for blowing and loading micro-nano particles provided by the invention utilizes the transformation process and adds the micro-nano particles with high dielectric constant difference in the air flow of the conventional melt-blowing processing, so as to realize the online blowing and loading of the micro-nano particles with high dielectric constant difference. The preparation principle is as follows: after the polymer raw material is melt extruded, from a spinneret to a fiber collecting end, the fiber shows a gradual transition process from a melt state to a solid state and is simultaneously accompanied by high speed and high-power drawing. When the fiber is in a melt state, the surface temperature of the fiber can reach 300 ℃, the physical property of the fiber melt is represented by liquid property, the whole stress of a surface molecular layer is unstable, and the fiber melt presents stronger surface tension, and meanwhile, spinning melt macromolecules can freely move and slide, so that possibility is provided for surface deformation of the fiber melt. The high surface tension and easy deformation characteristics of the fiber melt provide a natural place for compounding particles with high dielectric constant difference, the particles with high dielectric constant difference are dispersed in an airflow field of melt-blown spinning, the particles are sprayed on the surface of the fiber melt with certain kinetic energy while the airflow has the original blowing and stretching effects on melt fibers, and then the particles with high dielectric constant difference are drafted, lapped and formed along with the fiber melt, so that the purpose of online loading of the particles with high dielectric constant difference on the fiber melt is realized, and a non-woven fabric product with high dielectric constant difference is prepared.

In the whole spinning process, the temperature of fiber melt, the diameter of a spinneret hole, the receiving distance, the temperature and the speed of air flow, the content of particles with high dielectric constant difference in air flow, the quality of the particles with high dielectric constant difference and the like have great influence on the quantity, the uniformity and the fastness of the online loading of the particles.

Wherein the fiber melt temperature determines the surface tension and adhesion of the fiber melt, which in turn affects the load fastness of particles with high dielectric constant differences, and the fiber melt temperature is substantially the same as the extrusion temperature of the melt fiber. Therefore, the invention selects proper extrusion temperature according to the melting characteristics of the polymer fiber raw material, for example, the preferred extrusion temperature of the polypropylene fiber is 240 ℃, the preferred extrusion temperature of the polyethylene fiber is 230 ℃, and the preferred extrusion temperature of the polyester fiber is 290 ℃.

The spinning aperture and the receiving distance are closely related to the fiber diameter, the receiving distance is large, the jet loading capacity can be correspondingly increased, the receiving distance of the melt spinning is preferably 8-30 cm, the spinning aperture is 0.1-1 mm, and the spinning parameters are reasonably regulated and controlled according to actual requirements.

The air flow rate, which is in direct proportion to the load fastness of the particles having a high dielectric constant difference, and the mass of the particles having a high dielectric constant difference, which determine the loading amount and the loading uniformity of the particles having a high dielectric constant difference on the surface of the fiber, are influenced by the kinetic energy of the particles having a high dielectric constant difference. Therefore, when the melt-blown airflow is adopted, the temperature of the airflow is preferably 280-320 ℃, the gas flow rate is 300-500 m/s, and the ejection quantity of the micro-nano particles with high dielectric constant difference is 30-80 mg/s. The quality of the particles with high dielectric constant difference is related to the density and the particle size, so the micro-nano particles with high dielectric constant difference with the particle size less than or equal to 1 mu m are preferred in the invention.

In the following examples, the prepared self-charging nonwoven fabric was repeatedly washed with water to test the load fastness of particles with high dielectric constant difference, as follows:

cutting the self-charging non-woven fabric with the load of n% into a sample of 10cm multiplied by 10cm, and weighing the sample with the mass of m₀Soaking in distilled water, shaking and cleaning at room temperature for 30min, taking out, oven drying, and testing mass m₁Repeating the above steps, and sequentially measuring the mass m after cleaning for 2, 3, 4 and 5 times₂、m₃、m₄And m₅Then, the load amount after 5 times of washing was calculated by the following formula: