阅读说明：本技术 聚甲酸乙烯酯的合成方法及其湿法纺丝 (Method for synthesizing polyvinyl formate and wet spinning thereof ) 是由 刘大刚 钱军 于 2021-07-19 设计创作，主要内容包括：本发明公开了聚甲酸乙烯酯的合成方法,所述聚甲酸乙烯酯由以下原料制备而成：所述原料按重量份数比为：聚乙烯醇20-30份和甲酸93-120份；所述聚乙烯醇的醇解度为55％-98％,所述聚乙烯醇的分子量为67000-200000；本发明通过采用湿法纺丝进行制备聚甲酸乙烯酯纤维材料,接着使用注射泵、齿轮泵提供纺丝液,用滚筒牵引纺丝液,使纺丝液连续落入凝固浴中,初步成型,且初步成型后的纤维在凝固浴中保留一段时间,得到完全成型的聚甲酸乙烯酯纤维,本发明制备的纤维直径为0.5mm-0.8mm,长度无限制,制得聚甲酸乙烯酯纤维断裂伸长率高。(The invention discloses a method for synthesizing polyvinyl formate, which is prepared from the following raw materials: the raw materials comprise the following components in parts by weight: 20-30 parts of polyvinyl alcohol and 93-120 parts of formic acid; the alcoholysis degree of the polyvinyl alcohol is 55-98%, and the molecular weight of the polyvinyl alcohol is 67000-200000; the invention adopts wet spinning to prepare polyvinyl formate fiber material, then uses an injection pump and a gear pump to provide spinning solution, uses a roller to pull the spinning solution, leads the spinning solution to continuously fall into a coagulating bath, carries out primary forming, and keeps the fiber after the primary forming in the coagulating bath for a period of time to obtain the completely formed polyvinyl formate fiber, the diameter of the fiber prepared by the invention is 0.5mm-0.8mm, the length is not limited, and the prepared polyvinyl formate fiber has high elongation at break.)

1. The synthesis method of the polyvinyl formate is characterized by comprising the following steps: the polyvinyl formate is prepared from the following raw materials:

the raw materials comprise the following components in parts by weight: 20-30 parts of polyvinyl alcohol and 93-120 parts of formic acid;

the alcoholysis degree of the polyvinyl alcohol is 55-98%, and the molecular weight of the polyvinyl alcohol is 67000-200000;

the synthesis method of the polyvinyl formate comprises the following steps:

s1, putting formic acid serving as a solvent and a reactant into a reaction container;

s2, adding polyvinyl alcohol, and carrying out esterification reaction under the reaction conditions that the reaction time is 1-5 hours and the reaction temperature is 30-90 ℃;

and S3, adding a solution after the reaction is finished to separate out a product, and preparing the polyvinyl formate.

2. The method of synthesizing polyvinyl formate according to claim 1, wherein: in the step S2, before adding the polyvinyl alcohol for reaction, the atmosphere and pressure are detected, and the esterification reaction is performed under the standard atmosphere and pressure.

3. The method of synthesizing polyvinyl formate according to claim 1, wherein: in S3, the solution for precipitating the product is any one of water, ethanol, and a sodium hydroxide solution.

4. The method of synthesizing polyvinyl formate according to claim 1, wherein: the purity of the polyvinyl alcohol is preferably 80% -98%.

5. The method of synthesizing polyvinyl formate according to claim 1, wherein: the mass fraction of formic acid is preferably 88% or more.

6. The method of synthesizing polyvinyl formate according to claim 3, wherein: the mass of the precipitated solution is 5-6 times of that of the polyvinyl alcohol.

7. A wet spinning process of polyvinyl formate according to any one of claims 1 to 6, characterized by the following steps:

s10, taking the polyvinyl formate reaction solution prepared from the S3 as a spinning solution;

s20, preparing a polyvinyl formate fiber material by adopting wet spinning;

s30, providing a spinning solution by using an injection pump and a gear pump, drawing the spinning solution by using a roller, and making the spinning solution continuously fall into a coagulating bath for primary forming;

and S40, keeping the fiber after primary forming in a coagulating bath for a period of time to obtain the fully-formed polyvinyl formate fiber.

8. The wet spinning process of polyvinyl formate according to claim 7, characterized in that: in the step S30, before the spinning solution continuously falls into the coagulation bath, the position of the spinning needle is adjusted so that the spinning needle is obliquely suspended above the surface of the coagulation bath;

the coagulating bath is any one of water, ethanol and sodium hydroxide solution.

9. The wet spinning process of polyvinyl formate according to claim 7, characterized in that: in the S40, the retention time of the fiber after the primary molding in the coagulation bath is 8-10 min.

Technical Field

The invention relates to the technical field of spinning materials, in particular to a method for synthesizing polyvinyl formate and wet spinning thereof.

Background

The polyvinyl alcohol is a hydrophilic semi-crystal, has good water solubility, film forming property, adhesion and emulsibility, excellent heat resistance, wear resistance, oil resistance, solvent resistance, corrosion resistance, ultraviolet radiation resistance and other properties, is nontoxic and tasteless, has no corrosiveness, can be biologically degraded, has no irritation to skin, and can not cause skin allergy. Through the rapid development of decades, polyvinyl alcohol has become the water-soluble organic high molecular polymer with the largest yield in the world, and is widely applied to the industrial fields of adhesives, emulsifiers, dispersants, sizing agents, coatings, papermaking, films and the like besides being used as a vinylon raw material at present.

Spinning is the process of extruding a stream of fiberizing polymer fluid quantitatively from a spinneret orifice and solidifying the fluid stream in a suitable medium into fibers.

Esterified polyvinyl alcohol is a PVA derivative obtained by esterifying active hydroxyl in polyvinyl alcohol molecules with acid, and the esterified modified polyvinyl alcohol can be divided into two main classes of PVA inorganic acid esters and PVA organic acid esters according to different types of the acid participating in the reaction. The PVA inorganic acid ester mainly includes PVA phosphate, PVA sulfate and the like. The PVA organic acid ester is mainly prepared by esterifying polyvinyl alcohol with organic acid, acid anhydride, acyl chloride and the like.

In the prior art, the esterification reaction of polyvinyl alcohol and formic acid is not reported, and a synthetic method of polyvinyl formate and wet spinning thereof are provided for expanding the variety of polyvinyl alcohol ester.

Disclosure of Invention

The invention aims to provide a method for synthesizing polyvinyl formate and wet spinning thereof, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: the method for synthesizing polyvinyl formate comprises the following steps:

the raw materials comprise the following components in parts by weight: 20-30 parts of polyvinyl alcohol and 93-120 parts of formic acid;

the alcoholysis degree of the polyvinyl alcohol is 55-98%, and the molecular weight of the polyvinyl alcohol is 67000-200000;

the synthesis method of the polyvinyl formate comprises the following steps:

s1, putting formic acid serving as a solvent and a reactant into a reaction container;

s2, adding polyvinyl alcohol, and carrying out esterification reaction under the reaction conditions that the reaction time is 1-5 hours and the reaction temperature is 30-90 ℃;

and S3, adding a solution after the reaction is finished to separate out a product, and preparing the polyvinyl formate.

Preferably: in the step S2, before adding the polyvinyl alcohol for reaction, the atmosphere and pressure are detected, and the esterification reaction is performed under the standard atmosphere and pressure.

Preferably: in S3, the solution for precipitating the product is any one of water, ethanol, and a sodium hydroxide solution.

Preferably: the purity of the polyvinyl alcohol is preferably 80% -98%.

Preferably: the mass fraction of formic acid is preferably 88% or more.

Preferably: the mass of the precipitated solution is 5-6 times of that of the polyvinyl alcohol.

A wet spinning method of polyvinyl formate comprises the following steps:

s10, taking the polyvinyl formate reaction solution prepared from the S3 as a spinning solution;

s20, preparing a polyvinyl formate fiber material by adopting wet spinning;

s30, providing a spinning solution by using an injection pump and a gear pump, drawing the spinning solution by using a roller, and making the spinning solution continuously fall into a coagulating bath for primary forming;

and S40, keeping the fiber after primary forming in a coagulating bath for a period of time to obtain the fully-formed polyvinyl formate fiber.

Preferably: in the step S30, before the spinning solution continuously falls into the coagulation bath, the position of the spinning needle is adjusted so that the spinning needle is obliquely suspended above the surface of the coagulation bath;

the coagulating bath is any one of water, ethanol and sodium hydroxide solution.

Preferably: in the S40, the retention time of the fiber after the primary molding in the coagulation bath is 8-10 min.

Compared with the prior art, the invention has the beneficial effects that:

the invention uses formic acid as solvent and reactant, adds polyvinyl alcohol to carry out esterification reaction, adds solution to separate out product after reaction, the method for preparing polyvinyl formate is simple, and polyvinyl alcohol can be converted into polyvinyl formate under standard atmosphere and pressure;

secondly, preparing a polyvinyl formate fiber material by adopting wet spinning, then providing a spinning solution by using an injection pump and a gear pump, drawing the spinning solution by using a roller, making the spinning solution continuously fall into a coagulating bath, carrying out primary forming, and keeping the fiber subjected to the primary forming in the coagulating bath for a period of time to obtain the fully-formed polyvinyl formate fiber, wherein the diameter of the fiber prepared by the method is 0.5-0.8 mm, the length of the fiber is unlimited, and the prepared polyvinyl formate fiber has high elongation at break.

Drawings

FIG. 1 is an infrared absorption spectrum of polyvinyl formate of the present invention;

FIG. 2 is a representation of a polyvinyl formate fiber embodying features of the present invention;

FIG. 3 is a graph showing the elongation at break of polyvinyl formate fibers of different degrees of esterification according to the present invention;

FIG. 4 is a schematic diagram of the chemical formula of polyvinyl formate of the present invention;

FIG. 5 is a flow chart of the process for synthesizing polyvinyl formate of the present invention;

FIG. 6 is a flow chart of the wet spinning method of polyvinyl formate of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

Referring to fig. 1-6, the present invention provides a technical solution: the polyvinyl formate is prepared from the following raw materials:

the raw materials comprise the following components in parts by weight: 20-30 parts of polyvinyl alcohol and 93-120 parts of formic acid;

the alcoholysis degree of the polyvinyl alcohol is 55-98%, and the molecular weight of the polyvinyl alcohol is 67000-200000;

the synthesis method of the polyvinyl formate comprises the following steps:

s1, putting formic acid serving as a solvent and a reactant into a reaction container;

s2, adding polyvinyl alcohol, and carrying out esterification reaction under the reaction conditions that the reaction time is 1-5 hours and the reaction temperature is 30-90 ℃;

and S3, adding a solution after the reaction is finished to separate out a product, and preparing the polyvinyl formate.

In this embodiment, specifically: in S2, before adding polyvinyl alcohol for reaction, the atmosphere and pressure were measured, and esterification reaction was performed under a standard atmosphere and pressure.

In this embodiment, specifically: in S3, the solution for precipitating the product is any one of water, ethanol, and a sodium hydroxide solution.

In this embodiment, specifically: the purity of the polyvinyl alcohol is preferably 80% -98%.

In this embodiment, specifically: the mass fraction of formic acid is preferably 88% or more.

In this embodiment, specifically: the mass of the precipitated solution is 5-6 times of that of the polyvinyl alcohol.

A wet spinning method of polyvinyl formate comprises the following steps:

s10, taking the polyvinyl formate reaction solution prepared by S3 as spinning solution;

s20, preparing a polyvinyl formate fiber material by adopting wet spinning;

s30, providing a spinning solution by using an injection pump and a gear pump, drawing the spinning solution by using a roller, and making the spinning solution continuously fall into a coagulating bath for primary forming;

and S40, keeping the fiber after primary forming in a coagulating bath for a period of time to obtain the fully-formed polyvinyl formate fiber.

In this embodiment, specifically: in S30, before the spinning solution continuously falls into the coagulating bath, the position of a spinning needle is adjusted, so that the spinning needle is obliquely suspended above the surface of the coagulating bath;

the coagulating bath is any one of water, ethanol and sodium hydroxide solution.

In this embodiment, specifically: in S40, the retention time of the fiber after the primary forming in the coagulating bath is 8-10min, and the complete forming of the polyvinyl formate fiber is ensured.

Experimental example 1

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 50 ℃ and reacts for 3 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 57%. The reaction solution was selected as the spinning solution and distilled water as the coagulation bath at 20 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. The spinning solution is supplied using a syringe pump, a gear pump, or the like. The spinning solution continuously falls into the coagulation bath due to the viscosity, and is drawn by a roller to pass through the coagulation bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation.

Experimental example 2

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 50 ℃ and reacts for 4 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 53%.

Experimental example 3

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 50 ℃ and reacts for 5 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 48%. The reaction solution was selected as the spinning solution and distilled water as the coagulation bath at 20 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. The spinning solution is supplied using a syringe pump, a gear pump, or the like. The spinning solution continuously falls into the coagulation bath due to the viscosity, and is drawn by a roller to pass through the coagulation bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation.

Experimental example 4

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 60 ℃ and reacts for 2 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 45%.

Experimental example 5

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to be heated to 80 ℃, and the reaction lasts for 3 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 39%.

Experimental example 6

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to be heated to 80 ℃, and the reaction lasts for 1 hour. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 37%. The reaction solution was selected as the spinning solution and distilled water as the coagulation bath at 20 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. The spinning solution is supplied using a syringe pump, a gear pump, or the like. The spinning solution continuously falls into the coagulation bath due to the viscosity, and is drawn by a roller to pass through the coagulation bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation.

Experimental example 7

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 50 ℃ and reacts for 2 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 27%. The reaction solution was selected as the spinning solution and distilled water as the coagulation bath at 20 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. The spinning solution is supplied using a syringe pump, a gear pump, or the like. The spinning solution continuously falls into the coagulation bath due to the viscosity, and is drawn by a roller to pass through the coagulation bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation.

Experimental example 8

20g of polyvinyl alcohol is added into a three-neck flask with the volume of 3L, 93ml of formic acid is slowly dropped and rapidly and mechanically stirred, the mixture is heated in a slow water bath to 30 ℃ and reacts for 3 hours. After cooling, sampling and adding water for multiple times to separate out the product, and reserving the solution for potentiometric titration to determine the esterification degree. The degree of esterification of the polyvinyl formate was 18%. The reaction solution was selected as the spinning solution and distilled water as the coagulation bath at 20 ℃. The spinning needle head is a flat-head stainless steel needle head and is obliquely suspended above the surface of the coagulating bath liquid. The spinning solution is supplied using a syringe pump, a gear pump, or the like. The spinning solution continuously falls into the coagulation bath due to the viscosity, and is drawn by a roller to pass through the coagulation bath for forming. The fibers after the primary forming were left in the coagulation bath for 10min to ensure complete formation.

Experimental example 9

The invention also provides polyvinyl formate prepared by the synthesis method and performance test data of wet spinning by using the polyvinyl formate, which are shown as follows:

the obtained solid sample is ground, and the wave number in the infrared absorption spectrum relative to the raw material PVA is 1730cm-¹The absorption peak is C-O-C, and the absorption peak is 1180 cm-1.

The materials obtained according to experimental examples 1, 3, 6, 7, 8 were subjected to a stress strain test (see fig. 2), and for polyvinyl formate, the material with a low esterification rate had a low elongation at break (700%) and a low tensile strength (10.07MPa), and when the esterification rate reached 0.268, the material reached the maximum tensile strength (31.83MPa), and then as the esterification rate increased, the elongation at break gradually increased, and when the esterification rate reached 0.574, the elongation at break was 1113%, but the tensile strength was the lowest, 0.835 MPa.

Working principle or structural principle: the invention takes formic acid as solvent and reactant, adds polyvinyl alcohol to carry out esterification reaction, and adds solution to separate out the product after the reaction is finished, thus the method for preparing polyvinyl formate is simple, and polyvinyl alcohol can be converted into polyvinyl formate under standard atmosphere and pressure;

the invention adopts wet spinning to prepare polyvinyl formate fiber material, then uses an injection pump and a gear pump to provide spinning solution, uses a roller to pull the spinning solution, leads the spinning solution to continuously fall into a coagulating bath, carries out primary forming, and keeps the fiber after the primary forming in the coagulating bath for a period of time to obtain the completely formed polyvinyl formate fiber, the diameter of the fiber prepared by the invention is 0.5mm-0.8mm, the length is not limited, and the prepared polyvinyl formate fiber has high elongation at break.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.