阅读说明：本技术 纤维级聚苯硫醚工业产品的洗涤处理方法 (Washing treatment method of fiber-grade polyphenylene sulfide industrial product ) 是由 周兵 李正辉 薛颖 聂志超 刘伟强 于 2020-05-11 设计创作，主要内容包括：本发明公开了一种工业生产级别的纤维级聚苯硫醚产品的洗涤处理方法,该方法中,通过在特定条件下用醋酸钙溶液经过五次浆化处理纤维级聚苯硫醚树脂,不但可以明显改善熔流指数,且可以降低纤维级聚苯硫醚在熔融态的结晶温度,有助于后续纤维拉丝的加工处理。本发明方法工艺简单,洗涤效率高,处理设备为常规设备,安全,无危险药品,可以用于工业化生产。(The invention discloses a washing treatment method of an industrial production grade fiber-grade polyphenylene sulfide product, wherein the fiber-grade polyphenylene sulfide resin is subjected to five times of slurrying treatment by using a calcium acetate solution under specific conditions, so that the melt flow index can be obviously improved, the crystallization temperature of the fiber-grade polyphenylene sulfide in a molten state can be reduced, and the subsequent fiber drawing processing is facilitated. The method has the advantages of simple process, high washing efficiency, conventional treatment equipment, safety and no dangerous medicine, and can be used for industrial production.)

1. A washing treatment method of industrial production grade fiber grade polyphenylene sulfide products comprises the following steps:

1) conveying the fiber-grade polyphenylene sulfide crude product to a filter press, and adding water to carry out primary pulping, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5;

2) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing first filter pressing, and sending filtrate to a subsequent water treatment system;

3) after the filter pressing is finished, adding water into the filter press for secondary pulping, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5;

4) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, carrying out secondary filter pressing, and conveying filtrate to a washing water tank for temporary storage so as to facilitate washing and recycling of products of the next batch;

5) after the filter pressing is finished, adding the filtrate obtained in the step 4) into a filter press for third slurrying, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5;

6) repeating the step 4) for third filter pressing, and conveying the filtrate to a washing water tank for temporary storage so as to facilitate the washing recycling of the next batch of products;

7) after filter pressing is finished, adding a calcium acetate solution with a certain concentration and the filtrate obtained in the step 6) into a filter press for pulping for the fourth time, and ensuring that the mass percentage concentration of calcium acetate in the pulping solution is about 1%, so as to determine the using amount of the calcium acetate solution, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5;

8) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing fifth filter pressing, and sending filtrate to a subsequent water treatment system;

9) adding desalted water or distilled water into the filter press to carry out fifth slurrying;

10) and starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing fifth filter pressing, sending the fiber-grade polyphenylene sulfide to a subsequent drying system from the filter press after the filter pressing is finished, and sending filtrate to a washing water tank for temporary storage so as to facilitate next recycling, wherein the weight ratio of the crude product of the fiber-grade polyphenylene sulfide to the desalted water or distilled water is 1: 25-1: 5.

2. The washing treatment method as claimed in claim 1, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate in step 1) is 1: 10.

3. The washing treatment method as claimed in claim 1, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate in step 3) is 1: 10.

4. The washing treatment method as claimed in claim 1, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate in step 5) is 1: 10.

5. The washing treatment method as claimed in claim 1, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate in step 7) is 1: 10.

6. The washing treatment method as claimed in claim 1, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the demineralized or distilled water in step 10) is 1: 10.

7. The washing treatment method according to claim 1, wherein the calcium acetate solution in step 7) has a concentration of 5 to 30% by mass.

8. The washing treatment method according to claim 1, characterized in that the fiber-grade polyphenylene sulfide raw product in step 1) is prepared by:

1) adding 20-30 parts by weight of acetic anhydride, 150 parts by weight of sodium hydroxide 140-;

2) and transferring the sodium hydrosulfide solution from the dehydration reaction kettle to a subsequent polymerization reaction kettle, adding 190-280 parts by weight of p-dichlorobenzene, heating the polymerization reaction kettle to 265-280 ℃, keeping the stirring condition for 0.5h for polymerization reaction, then cooling to below 100 ℃ under the condition of keeping the pressure in the reactor unchanged, and finishing the reaction to obtain the fiber-grade polyphenylene sulfide crude product.

9. The washing treatment method as claimed in claim 1, wherein the types and contents of the components in the fiber-grade polyphenylene sulfide crude product are as follows: 42 percent of NMP, 4 percent of sodium chloride, 2 percent of sodium acetate, 2 percent of water and the balance of 50 percent of PPS according to mass percentage.

Technical Field

The invention belongs to the field of purification and washing treatment of industrial products, and particularly relates to a washing treatment method of an industrial production grade fiber-grade polyphenylene sulfide product.

Background

Polyphenylene sulfide (PPS for short) has the advantages of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability, excellent electrical property and the like, and is widely applied to the fields of electronics, automobiles, machinery and chemical industry. With the stricter requirements of the environmental protection smoke emission indexes in China, the environmental protection polyphenylene sulfide fiber filter bag is used more and more in the environmental protection field due to the unique filtering performance and the environmental resistance, so that the rapid development of the fiber-grade polyphenylene sulfide is promoted.

In the conventional process for synthesizing polyphenylene sulfide, for example, chinese patents CN1143652A and CN1793202A, the crude polyphenylene sulfide product obtained is doped with a certain amount of inorganic salts, and a small amount of organic impurities remains in the polyphenylene sulfide. These impurities are sublimated or vaporized at high temperature during the spinning process of polyphenylene sulfide, and cause bubble filaments or stub filaments, which affect spinning performance and product quality, so that washing treatment is necessary. In addition, the melt crystallization temperature is a key index for the subsequent spinning process, and the polyphenylene sulfide for spinning requires a lower melt crystallization temperature to prevent crystal fracture in the drawing process.

In order to solve the above problems and to enable modification of polyphenylene sulfide during washing, it is necessary to improve the prior art. The invention designs a washing treatment method of high molecular weight polyphenylene sulfide, and calcium acetate treatment is carried out on polyphenylene sulfide resin under specific conditions in the washing process, so that impurities such as inorganic salt, organic solvent and the like are effectively removed, the melt flow index is obviously improved, the crystallization temperature of a polyphenylene sulfide product in a molten state is reduced, and the polyphenylene sulfide treated by the method is ensured to obtain high-quality polyphenylene sulfide fibers in the subsequent spinning process.

Disclosure of Invention

In view of the problems of the prior art, according to one aspect of the present invention, an object of the present invention is to provide a method for washing and treating fiber-grade polyphenylene sulfide products in industrial production grade, wherein the method comprises treating fiber-grade polyphenylene sulfide resin with calcium acetate solution under specific conditions, so as to significantly improve the melt flow index, reduce the crystallization temperature of the fiber-grade polyphenylene sulfide in a molten state, and facilitate the processing and treatment of subsequent fiber drawing.

The washing treatment method comprises the following steps:

1) sending the fiber-grade polyphenylene sulfide crude product to a filter press, and adding water to carry out primary pulping, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5, and more preferably 1: 10;

2) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing first filter pressing, and sending filtrate to a subsequent water treatment system;

3) after the filter pressing is finished, adding water into the filter press for secondary pulping, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5, and more preferably 1: 10;

4) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, carrying out secondary filter pressing, and conveying filtrate to a washing water tank for temporary storage so as to facilitate washing and recycling of products of the next batch;

5) after the filter pressing is finished, adding the filtrate obtained in the step 4) into a filter press for third pulping, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5, and more preferably 1: 10;

6) repeating the step 4) for third filter pressing, and conveying the filtrate to a washing water tank for temporary storage so as to facilitate the washing recycling of the next batch of products;

7) after filter pressing is finished, adding a calcium acetate solution with a certain concentration and the filtrate obtained in the step 6) into a filter press for carrying out fourth slurrying, and ensuring that the mass percentage concentration of calcium acetate in the slurrying solution is about 1%, so as to determine the using amount of the calcium acetate solution, wherein the weight ratio of the fiber-grade polyphenylene sulfide crude product to the filtrate is 1: 25-1: 5, and more preferably 1: 10;

8) starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing fifth filter pressing, and sending filtrate to a subsequent water treatment system;

9) adding desalted water or distilled water into the filter press to carry out fifth slurrying;

10) and starting a stirring device of the filter press, stirring and mixing for 15min at 85-95 ℃, performing fifth filter pressing, sending the fiber-grade polyphenylene sulfide to a subsequent drying system from the filter press after the filter pressing is finished, sending filtrate to a washing water tank for temporary storage so as to facilitate next recycling, wherein the weight ratio of the crude product of the fiber-grade polyphenylene sulfide to the desalted water or distilled water is 1: 25-1: 5, and more preferably 1: 10.

Preferably, the concentration of the calcium acetate solution in the step 7) is 5 to 30 percent by mass.

Preferably, the fiber-grade polyphenylene sulfide crude product in step 1) is prepared as follows:

1) adding 20-30 parts by weight of acetic anhydride, 150 parts by weight of sodium hydroxide 140-;

2) and transferring the sodium hydrosulfide solution from the dehydration reaction kettle to a subsequent polymerization reaction kettle, adding 190-280 parts by weight of p-dichlorobenzene, heating the polymerization reaction kettle to 265-280 ℃, keeping the stirring condition for 0.5h for polymerization reaction, then cooling to below 100 ℃ under the condition of keeping the pressure in the reactor unchanged, and finishing the reaction to obtain the fiber-grade polyphenylene sulfide crude product.

The fiber-grade polyphenylene sulfide crude product comprises the following components in percentage by weight: 42 percent of NMP, 4 percent of sodium chloride, 2 percent of sodium acetate, 2 percent of water and the balance of 50 percent of PPS according to mass percentage.

The fiber-grade polyphenylene sulfide crude product is particularly suitable for wire drawing applications.

Advantageous effects

1. The washing treatment method has the advantages of simple process, high washing efficiency, conventional treatment equipment, safety and no dangerous medicine, and can be used for industrial production.

2. The treated fiber-grade polyphenylene sulfide resin can reduce the melt flow index and the crystallization temperature of a molten state, and obviously improve the characteristics of polyphenylene sulfide.

3. Each batch of washing water can be recycled, so that the waste water generated in the process is effectively reduced, and the sewage treatment cost is reduced.

4. The treated polyphenylene sulfide resin has improved application performance, can be better applied to fiber drawing processing, and is used in the high-end field.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a DSC analysis chart of a product before washing treatment in example 1;

FIG. 2 is a DSC analysis chart of the product after washing treatment in example 1

FIG. 3 is a DSC analysis chart of the product after washing treatment in example 2

FIG. 4 is a DSC analysis chart of the product after washing treatment of example 3

Detailed Description

Hereinafter, the present invention will be described in detail. Before the description is made, it should be understood that the terms used in the present specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Accordingly, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the invention.

The washing treatment method needs to be carried out at a specific temperature, namely 85-95 ℃, and the residual solvent NMP in the polyphenylene sulfide product can be better washed within the temperature range, so that the NMP residue is reduced as much as possible. When the content is outside the above range, the effect of removing NMP as a solvent is not satisfactory.

The amount of water added per time in the washing treatment method according to the present invention is not particularly limited, but the weight ratio of the fiber-grade polyphenylene sulfide crude product to the added water or filtrate is 1:25 to 1:5, more preferably 1:10, in view of efficiency and economy. If the ratio is more than 1:25, the added water or filtrate is too much, so that the impurity removal rate can be improved each time, but more waste water is generated, and the method is not economical and environment-friendly; if the ratio is less than 1:5, namely the added water or the filtrate is insufficient, the impurity removal rate per time is reduced, and the washing and pressure filtration times are increased to improve the total impurity removal rate, which is not economical.

According to the washing treatment method, the calcium acetate solution is adopted as the washing additive for the fiber-grade crude polyphenylene sulfide product with specific components, impurities and contents, so that the content of the impurities in the fiber-grade crude polyphenylene sulfide product is greatly reduced, and meanwhile, the calcium acetate does not remain in the polyphenylene sulfide product. In the fourth slurry of the washing treatment method according to the present invention, the amount of the calcium acetate solution to be used is determined by ensuring that the mass percentage concentration of calcium acetate in the slurry is about 1%.

The following examples are given by way of illustration of embodiments of the invention and are not to be construed as limiting the invention, and it will be understood by those skilled in the art that modifications may be made without departing from the spirit and scope of the invention. Unless otherwise specified, reagents and equipment used in the following examples are commercially available products.

And (3) performance testing:

1. the melt index change (temperature: 316 ℃ C., load: 5kg) of the fiber-grade polyphenylene sulfide before and after the washing treatment was measured by a melt index meter.

2. The changes in the melting crystallization points before and after the washing treatment of the polyphenylene sulfide resin were measured by Differential Scanning Calorimetry (DSC).