阅读说明：本技术 聚对苯二甲酰对苯二胺树脂的清洗方法 (Method for cleaning poly (p-phenylene terephthalamide) resin ) 是由 庹新林 赵海林 于 2019-10-25 设计创作，主要内容包括：本发明提供了聚对苯二甲酰对苯二胺树脂的清洗方法,涉及聚对苯二甲酰对苯二胺树脂清洗技术领域。本发明中,以脂肪族卤代烷烃、乙二胺四乙酸溶液及脱盐水分别作为清洗液,根据N-甲基吡咯烷酮和Ca<Sup>2+</Sup>在初产物中的特点,采用不同的清洗液及工艺参数,进行选择性清洗；对于微孔中的Ca<Sup>2+</Sup>高速搅拌使其脱离,再与乙二胺四乙酸根离子螯合,最后以脱盐水冲洗,提高了清洗效果；N-甲基吡咯烷酮基本全在S1产生的滤液中,溶剂回收利用需要处理的滤液量大大减少；采用不同的清洗液及工艺参数,降低了清洗液总用量,节约了水资源。(The invention provides a method for cleaning poly-p-phenylene terephthamide resin, and relates to the technical field of poly-p-phenylene terephthamide resin cleaning. In the invention, aliphatic halogenated alkane, ethylene diamine tetraacetic acid solution and desalted water are respectively used as cleaning liquids according to N-methyl pyrrolidone and Ca 2+ The characteristics of the primary product are that different cleaning solutions and process parameters are adopted to carry out selective cleaning; for Ca in micropores 2+ Stirring at high speed to separate, chelating with EDTA ion, and washing with desalted water to improve cleaning effect; the N-methyl pyrrolidone is basically completely contained in the filtrate generated in S1, and the amount of the filtrate needing to be treated by solvent recycling is greatly reduced; different cleaning liquids and process parameters are adopted, so that the total using amount of the cleaning liquids is reduced, and water resources are saved.)

1. A method for cleaning a poly (p-phenylene terephthalamide) resin,

comprises the following steps:

s1, taking 100 parts by mass of poly-p-phenylene terephthamide polymerization primary product, adding 100-150 parts by mass of aliphatic halogenated alkane, washing at a temperature lower than the boiling point of the used halogenated alkane, stirring at a speed of 200-400r/min for 5-15min, and performing vacuum filtration to obtain filtrate and solid product;

s2, cleaning the solid product obtained in S1, adding 100-160 parts by mass of ethylenediamine tetraacetic acid solution with the concentration of 0.03-0.08%, wherein the solution temperature is 80-100 ℃, the stirring speed is 750-2500r/min, the stirring time is 5-15min, heating is carried out to keep the solution temperature at 80-100 ℃, and vacuum filtration is carried out to obtain filtrate and a solid product;

s3, cleaning the solid product obtained in the S2, adding 200 parts by mass of 100-100 ℃ desalted water, stirring at 200-400r/min for 5-15min, and performing vacuum filtration to obtain a filtrate and a solid product;

s4, cleaning the solid product obtained in the S3, adding 100-200 parts by mass of desalted water, controlling the temperature of the desalted water to be 40-100 ℃, and performing vacuum filtration to obtain filtrate and a solid product;

s5, drying the solid product obtained in the S4 at 80-105 ℃ for 12 h.

2. The method of claim 1, wherein the alkyl halide used in S1 is chloroform.

3. The method for cleaning poly (p-phenylene terephthalamide) resin according to claim 1, wherein the stirring speed in S2 is 2000-2500 r/min.

4. The method for cleaning a polyparaphenylene terephthalamide resin according to claim 1, wherein the temperature of the desalted water in S3 is 60 to 80 ℃.

Technical Field

The invention relates to the technical field of poly-p-phenylene terephthamide resin cleaning, in particular to a method for cleaning poly-p-phenylene terephthamide resin.

Background

The para-aramid fiber has excellent physical and chemical properties of high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight and the like, is widely applied to military fields and civil fields of aerospace and the like, and has wide application as a reinforcing material in composite materials.

The para-aramid fiber is spun by poly-p-phenylene terephthamide resin, and the purity of the poly-p-phenylene terephthamide resin directly determines the quality of the para-aramid fiber. Poly (p-phenylene terephthalamide)Diamine resins, typically made from terephthaloyl chloride and p-phenylenediamine in the presence of a solubilizing salt CaCl₂In the solvent of N-methylpyrrolidone. In the initial product after the polymerization is finished, the solvent N-methyl pyrrolidone and the cosolvent salt CaCl₂Mixing the raw material serving as impurities with poly (p-phenylene terephthalamide) resin serving as a main product, and cleaning the initial product to remove N-methyl pyrrolidone and CaCl₂So as to improve the purity of the poly-p-phenylene terephthamide resin.

The poly-p-phenylene terephthamide resin is of a honeycomb structure, the surface of the poly-p-phenylene terephthamide resin is provided with micropores, and Ca²The poly (p-phenylene terephthalamide) resin is easy to enter micropores, is firmly adhered to the inside of the poly (p-phenylene terephthalamide) resin, and is difficult to clean by conventional washing, so that the poly (p-phenylene terephthalamide) resin has high impurity content and poor subsequent spinning quality. Moreover, the solvent N-methyl pyrrolidone has higher cost, can be cleaned out and recycled, and is beneficial to reducing the production cost.

At present, the mode of water washing with more water is the mode of vacuum belt type countercurrent water washing, and the filtration efficiency of the mode of water washing and the concentration of the recovered mother liquor hardly meet the basic requirements, and the mode of water washing is repeated, time-consuming and water-consuming, and has very serious water resource waste.

Disclosure of Invention

The invention provides a method for cleaning poly-p-phenylene terephthamide resin, which uses aliphatic halogenated alkane, ethylene diamine tetraacetic acid solution and desalted water as cleaning liquid respectively, and cleans the poly-p-phenylene terephthamide resin primary product for many times by controlling the temperature of the cleaning liquid and relevant technological parameters.

The technical scheme adopted by the invention is a method for cleaning poly (p-phenylene terephthalamide) resin, which comprises the following steps:

s1, taking 100 parts by mass of poly-p-phenylene terephthamide polymerization primary product, adding 100-150 parts by mass of aliphatic halogenated alkane, washing at a temperature lower than the boiling point of the aliphatic halogenated alkane, stirring at a speed of 200-400r/min for 5-15min, and performing vacuum filtration to obtain filtrate and solid product;

s2, cleaning the solid product obtained in S1, adding 100-160 parts by mass of ethylenediamine tetraacetic acid solution with the concentration of 0.03-0.08%, wherein the solution temperature is 80-100 ℃, the stirring speed is 750-2500r/min, the stirring time is 5-15min, heating is carried out to keep the solution temperature at 80-100 ℃, and vacuum filtration is carried out to obtain filtrate and a solid product;

s3, cleaning the solid product obtained in the S2, adding 200 parts by mass of 100-100 ℃ desalted water, stirring at 200-400r/min for 5-15min, and performing vacuum filtration to obtain a filtrate and a solid product;

s4, cleaning the solid product obtained in the S3, adding 100-200 parts by mass of desalted water, controlling the temperature of the desalted water to be 40-100 ℃, and performing vacuum filtration to obtain filtrate and a solid product;

s5, drying the solid product obtained in the S4 at 80-105 ℃ for 12 h.

Further, the haloalkane used in S1 is chloroform.

Further, the stirring speed in S2 was 2000-2500 r/min.

Further, in S3, the temperature of the desalted water is 60 to 80 ℃.

In the invention, vacuum filtration is adopted in S1, S2, S3 and S4, so that solid-liquid separation is thorough, and the solid surface is relatively dry. In S1, aliphatic halogenated hydrocarbon is used as a cleaning liquid, and the stirring speed is controlled at 200-400 r/min. Experimental research proves that Ca entering micropores of poly (p-phenylene terephthalamide) resin²⁺The poly-p-phenylene terephthalamide resin is basically not separated under the condition of the rotation speed of 200-400r/min, and only when the stirring speed reaches 750r/min, most Ca in micropores²⁺And (4) separating out. Thus, the filtrate solvent in S1 is high in N-methylpyrrolidone content, while Ca²⁺The content is small, and in fact, the N-methylpyrrolidone adhered to the primary product is considered to be washed away in S1, that is, in the washing method of the present invention, the filtrate produced in S1 is only required to be subjected to a recovery treatment for the recovery and utilization of the N-methylpyrrolidone as a solvent.

Ca entering micropores of poly (p-phenylene terephthalamide) resin²⁺The cleaning difficulty is high, in the invention, the stirring speed is 750-0r/min, most of Ca²⁺Separated from the micropores and reacted with EDTA ions to generate chelate, which is convenient for cleaning Ca²⁺. In S2, S3 and S4, the temperature of the EDTA solution and the desalted water is higher than the normal temperature, and in S2, heating and heat preservation measures are also taken, so that the dissolving capacity of the solution is improved, and chelate, EDTA solution and Cl can be dissolved^-And trace residual N-methyl pyrrolidone is washed away. While the cleaning effect is ensured, the use amount of the solution and the desalted water is reduced, solid substances are separated out from the filtered filtrate after the temperature is reduced, and the treatment is simple.

Compared with the prior art, the invention has the advantages that:

1) according to N-methylpyrrolidone and Ca²⁺The characteristics of the primary product are that different cleaning solutions and process parameters are adopted to carry out selective cleaning;

2) selective cleaning of Ca in the micropores²⁺Stirring at a high speed to separate the poly (p-phenylene terephthalamide) resin, chelating with ethylene diamine tetraacetic acid ions, washing with desalted water, and testing ash content to obtain the poly (p-phenylene terephthalamide) resin with calcium ion content of less than 50ppm, high purity and good cleaning effect;

3) selective cleaning, the N-methyl pyrrolidone is basically in the filtrate generated in S1, and the amount of the filtrate needing to be treated for solvent recycling is greatly reduced;

4) different cleaning liquids and process parameters are adopted, so that the total using amount of the cleaning liquids is reduced, and water resources are saved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments.