阅读说明：本技术 芳香族聚酰胺涂层隔膜及其制备方法 (Aromatic polyamide coating diaphragm and preparation method thereof ) 是由 袁海朝 徐锋 郗腾 苏碧海 苏柳 李腾 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种芳香族聚酰胺涂层隔膜及其制备方法,制备方法包括：将第二浆料涂覆在基膜的一侧或两侧,在基膜上得到第一涂层,将覆盖有第一涂层的基膜浸入第一浆料中,再浸入清洗剂中,用于洗去表面的溶剂,干燥,得到芳香族聚酰胺涂层隔膜,其中,第一浆料包括：去离子水、缚酸剂和二胺单体；第二浆料包括：溶剂和酰氯单体。相较于传统方法备简单,本发明将聚合工艺与涂覆工艺整合,大大节约了生产成本,提高了生产效率,所制得芳香族聚酰胺涂层隔膜较传统方法在耐热性上优势更加明显。本发明直接在基膜表面聚合生成对位芳香族聚酰胺纤维,直接生成涂覆层,无需二次加工涂覆。(The invention discloses an aromatic polyamide coating diaphragm and a preparation method thereof, wherein the preparation method comprises the following steps: coating the second slurry on one side or two sides of the base film to obtain a first coating layer on the base film, immersing the base film covered with the first coating layer into the first slurry, then immersing into a cleaning agent for washing off a solvent on the surface, and drying to obtain the aromatic polyamide coating diaphragm, wherein the first slurry comprises: deionized water, an acid-binding agent and a diamine monomer; the second slurry includes: solvents and acid chloride monomers. Compared with the traditional method, the preparation method is simple, the polymerization process and the coating process are integrated, the production cost is greatly saved, the production efficiency is improved, and the prepared aromatic polyamide coating diaphragm has more obvious advantages in heat resistance compared with the traditional method. The invention directly polymerizes on the surface of the basement membrane to generate the para-position aromatic polyamide fiber and directly generates the coating layer without secondary processing and coating.)

1. A preparation method of an aromatic polyamide coating membrane is characterized by comprising the following steps: coating the second slurry on one side or two sides of the base film to obtain a first coating on the base film, immersing the base film covered with the first coating into the first slurry for 5-15 min, then immersing into a cleaning agent for 5-30 min, washing off a solvent on the surface, drying at 40-65 ℃ for 30-120 s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 5-30 parts by mass of an acid-binding agent and 5-60 parts by mass of a diamine monomer;

the second slurry includes: 100 parts by mass of solvent and 10-40 parts by mass of acyl chloride monomer.

2. The method according to claim 1, wherein the coating is performed by roll coating when one side is coated, the coating is performed by roll coating or dip coating when both sides are coated, and the thickness of the first coating layer is 1 to 10 μm.

3. The method according to claim 1, wherein the acid-binding agent is a salt capable of reacting with hydrogen chloride, the diamine monomer is p-phenylenediamine or m-phenylenediamine, the solvent is an organic solvent that is immiscible with water and capable of dissolving the acid chloride monomer, and the acid chloride monomer is terephthaloyl chloride or isophthaloyl chloride.

4. The preparation method of claim 3, wherein the acid scavenger is one or more of sodium carbonate, sodium bicarbonate, sodium acetate and sodium hydrogen phosphate.

5. The method according to claim 3, wherein the solvent is dichloromethane or toluene.

6. The method of preparing according to claim 1, wherein the method of preparing the first slurry is: and mixing the deionized water and an acid-binding agent, stirring for 5-15 min to dissolve the acid-binding agent in the deionized water, adding the diamine monomer, and stirring for 5-15 min to dissolve the diamine monomer.

7. The method of producing according to claim 1, characterized in that the method of producing the second slurry is: and mixing the solvent and the acyl chloride monomer, and stirring for 5-15 min to dissolve the acyl chloride monomer.

8. The preparation method of claim 1, wherein the cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 in parts by weight.

9. The separator with the aromatic polyamide coating obtained by the preparation method according to claim 1 to 8.

Technical Field

The invention belongs to the technical field of battery diaphragms, and particularly relates to an aromatic polyamide coating diaphragm and a preparation method thereof.

Background

Due to the vigorous development of electric vehicles, the safety of lithium ion batteries is receiving increasing attention. Thermal runaway is an important aspect that leads to reduced safety of lithium ion batteries. At present, the diaphragm commonly used for the lithium ion battery is a polyethylene diaphragm or a polyethylene ceramic coating diaphragm, and although the thermal safety of the latter is improved compared with the former, the latter still cannot meet the standard of the lithium ion battery for high thermal safety.

Aromatic polyamide is a novel material with high strength, high modulus, high temperature resistance and chemical corrosion resistance, and becomes an important modern chemical product after being developed in the past century and the fifties for decades. The diaphragm coated by dissolving the aromatic polyamide has the highest rupture temperature of more than 400 ℃ and is far higher than 130 ℃ of the polyethylene diaphragm, and the diaphragm is an excellent heat-resistant material. The application method of the aromatic polyamide on the diaphragm is mainly to dissolve fibers in a polar solvent, and then to separate out and solidify polyamide on the surface of the diaphragm through coating and extraction to form the aromatic polyamide coating diaphragm. However, after the para-aramid is synthesized into fibers, it cannot be dissolved in a polar solvent due to its own rigid long chain and a large number of intermolecular hydrogen bonds, which makes a secondary coating process of such materials very difficult.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of an aromatic polyamide coating diaphragm.

The invention also aims to provide the aromatic polyamide coating diaphragm obtained by the preparation method, the aromatic polyamide coating diaphragm is prepared by immersing a base membrane coated with acyl chloride monomers into the first slurry by using an interfacial polymerization method, polymerizing diamine monomers and the acyl chloride monomers on the surface of the diaphragm to generate aromatic polyamide, and cleaning and drying the aromatic polyamide coating diaphragm.

The purpose of the invention is realized by the following technical scheme.

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on one side or two sides of the base film to obtain a first coating on the base film, immersing the base film covered with the first coating into the first slurry for 5-15 min, then immersing into a cleaning agent for 5-30 min, washing off a solvent on the surface, drying at 40-65 ℃ for 30-120 s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 5-30 parts by mass of an acid-binding agent and 5-60 parts by mass of a diamine monomer;

the second slurry includes: 100 parts by mass of solvent and 10-40 parts by mass of acyl chloride monomer.

In the technical scheme, the coating mode is roll coating when one side is coated, the coating mode is roll coating or dip coating when two sides are coated, and the thickness of the first coating is 1-10 mu m.

In the technical scheme, the acid-binding agent is a salt capable of reacting with hydrogen chloride, the diamine monomer is p-phenylenediamine or m-phenylenediamine, the solvent is an organic solvent which is immiscible with water and capable of dissolving the acyl chloride monomer, and the acyl chloride monomer is terephthaloyl chloride or isophthaloyl chloride.

In the technical scheme, the acid-binding agent is one or a mixture of more of sodium carbonate, sodium bicarbonate, sodium acetate and sodium hydrogen phosphate.

In the above technical scheme, the solvent is dichloromethane or toluene.

In the above technical solution, the method for preparing the first slurry comprises: and mixing the deionized water and an acid-binding agent, stirring for 5-15 min to dissolve the acid-binding agent in the deionized water, adding the diamine monomer, and stirring for 5-15 min to dissolve the diamine monomer.

In the above technical solution, the method for preparing the second slurry comprises: and mixing the solvent and the acyl chloride monomer, and stirring for 5-15 min to dissolve the acyl chloride monomer.

In the technical scheme, the cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 in parts by weight.

The aromatic polyamide coating diaphragm obtained by the preparation method.

Compared with the traditional method, the preparation method is simple, the polymerization process and the coating process are integrated, the production cost is greatly saved, the production efficiency is improved, and the prepared aromatic polyamide coating diaphragm has more obvious advantages in heat resistance compared with the traditional method. The invention directly polymerizes on the surface of the basement membrane to generate the para-position aromatic polyamide fiber and directly generates the coating layer without secondary processing and coating.

Detailed Description

The technical scheme of the invention is further explained by combining specific examples.

The following examples are examples of drug purchase sources as follows:

chemical reagents of the national pharmaceutical group of m/p-phthaloyl chloride and m/p-phenylenediamine

Hexing chemical reagent manufacturing Co., Ltd, acid-binding agent Tianjin City

Chemical products Limited of Dichloromethane Changzhou Chengzekai

Toluene Beijing Zhongyuan Huadun Kong Co Ltd

The instruments and models tested in the following examples were as follows:

heat collection type constant temperature magnetic force heating stirrer Shanghai Yuying Instrument Limited

Constant temperature magnetic stirrer Limited liability company for consolidated City Yaohua instruments

Hangzhou David scientific and education instruments Co Ltd of laboratory coating machine

The base films used in the following examples were: a polyethylene separator.

Example 1

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on one side of a base film in a roller coating mode to obtain a first coating with the thickness of 2 mu m on the base film (the thickness of the base film is 9 mu m), soaking the base film covered with the first coating into the first slurry for 10min to ensure that an acyl chloride monomer and a diamine monomer fully react to generate polyamide on the surface of the diaphragm, soaking the diaphragm into a cleaning agent for 20min to wash off a solvent on the surface, drying the diaphragm at 60 ℃ for 40s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 15 parts by mass of an acid-binding agent and 45 parts by mass of a diamine monomer; the method for preparing the first slurry comprises the following steps: mixing deionized water and an acid-binding agent, stirring for 5min to dissolve the acid-binding agent in the deionized water, adding a diamine monomer, and stirring for 10min to dissolve the diamine monomer.

The second slurry includes: 100 parts by mass of a solvent and 30 parts by mass of an acid chloride monomer. The method for preparing the second slurry comprises the following steps: the solvent and the acid chloride monomer were mixed and stirred for 5min to dissolve the acid chloride monomer.

The acid-binding agent is salt capable of reacting with hydrogen chloride, the acid-binding agent is sodium carbonate, the diamine monomer is p-phenylenediamine, the solvent is an organic solvent which is immiscible with water and capable of dissolving the acyl chloride monomer, the solvent is dichloromethane, and the acyl chloride monomer is terephthaloyl chloride.

The cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 according to the parts by weight of the substances.

Example 2

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on two sides of the base film in a dip coating mode to obtain a first coating layer with the thickness of 1.5 mu m on each side of the base film (the thickness of the base film is 12 mu m), immersing the base film covered with the first coating layer into the first slurry for 8min to ensure that acyl chloride monomers and diamine monomers fully react to generate polyamide on the surface of the diaphragm, immersing the diaphragm into a cleaning agent for 15min to wash off the solvent on the surface, drying the diaphragm at 50 ℃ for 70s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 18 parts by mass of an acid-binding agent and 60 parts by mass of a diamine monomer; the method for preparing the first slurry comprises the following steps: mixing deionized water and an acid-binding agent, stirring for 8min to dissolve the acid-binding agent in the deionized water, adding a diamine monomer, and stirring for 10min to dissolve the diamine monomer.

The second slurry includes: 100 parts by mass of a solvent and 40 parts by mass of an acid chloride monomer. The method for preparing the second slurry comprises the following steps: the solvent and the acid chloride monomer were mixed and stirred for 10min to dissolve the acid chloride monomer.

The acid-binding agent is salt capable of reacting with hydrogen chloride, the acid-binding agent is sodium bicarbonate, the diamine monomer is p-phenylenediamine, the solvent is an organic solvent which is immiscible with water and capable of dissolving the acyl chloride monomer, the solvent is dichloromethane, and the acyl chloride monomer is terephthaloyl chloride.

The cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 according to the parts by weight of the substances.

Example 3

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on one side of a base film in a roller coating mode to obtain a first coating with the thickness of 4 mu m on the base film (the thickness of the base film is 12 mu m), soaking the base film covered with the first coating into the first slurry for 15min to ensure that an acyl chloride monomer and a diamine monomer fully react to generate polyamide on the surface of the diaphragm, soaking the diaphragm into a cleaning agent for 30min to wash off a solvent on the surface, drying at 60 ℃ for 100s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 12 parts by mass of an acid-binding agent and 30 parts by mass of a diamine monomer; the method for preparing the first slurry comprises the following steps: mixing deionized water and an acid-binding agent, stirring for 8min to dissolve the acid-binding agent in the deionized water, adding a diamine monomer, and stirring for 5min to dissolve the diamine monomer.

The second slurry includes: 100 parts by mass of a solvent and 20 parts by mass of an acid chloride monomer. The method for preparing the second slurry comprises the following steps: the solvent and the acid chloride monomer were mixed and stirred for 15min to dissolve the acid chloride monomer.

The acid-binding agent is salt capable of reacting with hydrogen chloride, the acid-binding agent is sodium carbonate, the diamine monomer is m-phenylenediamine, the solvent is an organic solvent which is immiscible with water and capable of dissolving the acyl chloride monomer, the solvent is dichloromethane, and the acyl chloride monomer is isophthaloyl dichloride.

The cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 according to the parts by weight of the substances.

Example 4

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on two sides of a base film in a dip-coating mode, obtaining a first coating with the thickness of 2 mu m on each side of the base film (the thickness of the base film is 16 mu m), immersing the base film covered with the first coating into the first slurry for 5min to ensure that acyl chloride monomers and diamine monomers fully react to generate polyamide on the surface of the diaphragm, immersing the diaphragm into a cleaning agent for 10min to wash off a solvent on the surface, drying the diaphragm at 45 ℃ for 45s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 20 parts by mass of an acid-binding agent and 45 parts by mass of a diamine monomer; the method for preparing the first slurry comprises the following steps: mixing deionized water and an acid-binding agent, stirring for 12min to dissolve the acid-binding agent in the deionized water, adding a diamine monomer, and stirring for 8min to dissolve the diamine monomer.

The second slurry includes: 100 parts by mass of a solvent and 35 parts by mass of an acid chloride monomer. The method for preparing the second slurry comprises the following steps: the solvent and the acid chloride monomer were mixed and stirred for 10min to dissolve the acid chloride monomer.

The acid-binding agent is salt capable of reacting with hydrogen chloride, the acid-binding agent is sodium acetate, the diamine monomer is m-phenylenediamine, the solvent is an organic solvent which is immiscible with water and capable of dissolving the acyl chloride monomer, the solvent is toluene, and the acyl chloride monomer is isophthaloyl dichloride.

The cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 according to the parts by weight of the substances.

Example 5

A preparation method of an aromatic polyamide coating membrane comprises the following steps: coating the second slurry on two sides of a base film in a dip coating mode, obtaining a first coating with the thickness of 1 mu m on one side of the base film (the thickness of the base film is 8 mu m), obtaining a first coating with the thickness of 2 mu m on the other side of the base film, immersing the base film covered with the first coating into the first slurry for 10min to ensure that an acyl chloride monomer and a diamine monomer fully react to generate polyamide on the surface of the diaphragm, immersing the polyamide in a cleaning agent for 20min to wash off a solvent on the surface, drying the polyamide at 50 ℃ for 60s to obtain the aromatic polyamide coating diaphragm, wherein,

the first slurry includes: 100 parts by mass of deionized water, 10 parts by mass of an acid-binding agent and 40 parts by mass of a diamine monomer; the method for preparing the first slurry comprises the following steps: mixing deionized water and an acid-binding agent, stirring for 15min to dissolve the acid-binding agent in the deionized water, adding a diamine monomer, and stirring for 12min to dissolve the diamine monomer.

The second slurry includes: 100 parts by mass of a solvent and 20 parts by mass of an acid chloride monomer. The method for preparing the second slurry comprises the following steps: the solvent and the acid chloride monomer were mixed and stirred for 12min to dissolve the acid chloride monomer.

The acid-binding agent is salt capable of reacting with hydrogen chloride, and is a mixture of sodium carbonate and sodium bicarbonate, wherein the ratio of the sodium carbonate to the sodium bicarbonate is 1:1, the diamine monomer is p-phenylenediamine, the solvent is an organic solvent which is not miscible with water and can dissolve the acyl chloride monomer, the solvent is dichloromethane, and the acyl chloride monomer is terephthaloyl chloride.

The cleaning agent is a mixture of water and ethanol, and the ratio of the water to the ethanol is 1:1 according to the parts by weight of the substances.

Comparative example 1

The lithium battery diaphragm slurry comprises the following components in parts by weight: 100 parts of deionized water, 5 parts of sodium polyacrylate, 10 parts of ethanol, 5 parts of sodium carboxymethylcellulose, 5 parts of water-based polyacrylate and 50 parts of aluminum oxide (the particle size is 0.5-3 mu m).

The preparation method comprises the following steps:

step 1: mixing and stirring the sodium polyacrylate and the deionized water at the stirring speed of 1000rpm/min for 20min to obtain a first liquid;

step 2: mixing and stirring the first liquid and alumina at the stirring speed of 3000rpm/min for 30-150min to obtain a second liquid;

and step 3: mixing and stirring the second liquid and ethanol at the stirring speed of 1000rpm/min for 30min to obtain a third liquid;

and 4, step 4: mixing and stirring the third liquid and sodium carboxymethylcellulose at the stirring speed of 1500rpm/min for 30min to obtain a fourth liquid;

and 5: mixing and stirring the fourth liquid and the water-based polyacrylate at the stirring speed of 1500rpm/min for 30min to obtain lithium battery diaphragm slurry;

and coating the lithium battery diaphragm slurry on a 9-micron base film (the base film is a polyethylene diaphragm, and the thickness of the base film is 9 microns) in a roller coating mode, wherein the coating thickness is 3 microns, so that the aluminum oxide coating diaphragm is obtained.

Comparative example 2

The lithium battery diaphragm slurry comprises the following components in parts by weight: 100 parts of N-methyl pyrrolidone, 2 parts of lithium chloride, 10 parts of para-aramid short fiber and 50 parts of tripropylene glycol.

Step 1: adding lithium chloride into N-methylpyrrolidone, stirring for 30min at 80 ℃, and completely dissolving the lithium chloride to obtain a first liquid;

step 2: adding the para-aramid short fiber into the first liquid, stirring for 20 hours at 80 ℃, and completely dissolving the para-aramid short fiber to obtain a second liquid;

and step 3: adding tripropylene glycol into the second liquid, and stirring at normal temperature for 60min to obtain lithium battery diaphragm slurry;

coating the lithium battery diaphragm slurry on a 9-micron base film (the base film is a polyethylene diaphragm) in a roller coating mode, wherein the coating thickness is 3 microns, and thus obtaining the para-aramid coated diaphragm.

The aromatic polyamide coating membranes obtained in examples 1 to 5, the alumina coating membrane obtained in comparative example 1, and the para-aramid coating membrane obtained in comparative example 2 were tested, and the test results are shown in table 1.

TABLE 1

The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.