阅读说明：本技术 一种自修复水性聚氨酯薄膜及其制备方法 (Self-repairing waterborne polyurethane film and preparation method thereof ) 是由 易昌凤 张宏量 杨晓昕 黄漂 于 2020-11-11 设计创作，主要内容包括：本发明属于自修复材料制备技术领域,提供一种自修复水性聚氨酯薄膜的制备方法,包括以下步骤：1)将聚四氢呋喃二醇溶于丙酮中,加入异佛尔酮二异氰酸酯和催化剂,反应后生成聚氨酯预聚体；2)在聚氨酯预聚体中依次加入N-甲基吡咯烷酮和2,2-二羟甲基丙酸、2-羟乙基二硫化物、三乙胺,搅拌反应后得到自修复水性聚氨酯乳液；3)在聚四氟乙烯板上浇筑自修复水性聚氨酯乳液并干燥,得到自修复水性聚氨酯薄膜。本发明引入了可逆二硫键,基于二硫键的不稳定性,其共价键易断裂与其他的硫原子发生重组,可利用二硫键与巯基之间的氧化还原反应来实现自修复,因此制备的水性聚氨酯薄膜具有良好的自修复性能。(The invention belongs to the technical field of self-repairing material preparation, and provides a preparation method of a self-repairing waterborne polyurethane film, which comprises the following steps: 1) dissolving polytetrahydrofuran diol in acetone, adding isophorone diisocyanate and a catalyst, and reacting to generate a polyurethane prepolymer; 2) sequentially adding N-methyl pyrrolidone, 2-dimethylolpropionic acid, 2-hydroxyethyl disulfide and triethylamine into the polyurethane prepolymer, and stirring for reaction to obtain a self-repairing aqueous polyurethane emulsion; 3) and pouring the self-repairing waterborne polyurethane emulsion on the polytetrafluoroethylene board and drying to obtain the self-repairing waterborne polyurethane film. The reversible disulfide bond is introduced, the covalent bond is easy to break and is recombined with other sulfur atoms based on the instability of the disulfide bond, and the self-repairing can be realized by using the redox reaction between the disulfide bond and the sulfydryl, so that the prepared waterborne polyurethane film has good self-repairing performance.)

1. A preparation method of a self-repairing waterborne polyurethane film is characterized by comprising the following steps:

1) dissolving polytetrahydrofuran diol in acetone, adding isophorone diisocyanate and a catalyst, and reacting to generate a polyurethane prepolymer;

2) sequentially adding N-methyl pyrrolidone, 2-dimethylolpropionic acid, 2-hydroxyethyl disulfide and triethylamine into the polyurethane prepolymer, and stirring for reaction to obtain a self-repairing aqueous polyurethane emulsion;

3) and pouring the self-repairing waterborne polyurethane emulsion on the polytetrafluoroethylene board and drying to obtain the self-repairing waterborne polyurethane film.

2. The method for preparing a self-repairing aqueous polyurethane film according to claim 1, wherein: the amount of the reagent used for preparing the self-repairing aqueous polyurethane emulsion is 3g of polytetrahydrofuran diol, 2g of isophorone diisocyanate, 5ml of N-methyl pyrrolidone, 0.275g of 2, 2-dimethylolpropionic acid, 0.3-0.9 g of 2-hydroxyethyl disulfide and 0.202g of triethylamine.

3. The method for preparing a self-repairing aqueous polyurethane film according to claim 2, wherein the amount of 2-hydroxyethyl disulfide in the reagent for preparing the self-repairing aqueous polyurethane emulsion is 0.6 to 0.75 g.

4. The method for preparing a self-repairing aqueous polyurethane film according to claim 1, wherein the step 1) of dissolving polytetrahydrofuran diol in acetone comprises the following specific steps: the polytetrahydrofuran diol is dissolved in acetone after being pumped at 130 ℃.

5. The method for preparing a self-repairing aqueous polyurethane film according to claim 1, wherein the reaction in step 1) is carried out under the conditions of 70 ℃ to 80 ℃ for 2 hours.

6. The method for preparing a self-repairing aqueous polyurethane film according to claim 1, wherein the step 2) of preparing the self-repairing aqueous polyurethane emulsion from the polyurethane prepolymer comprises the following specific steps: adding N-methyl pyrrolidone and 2, 2-dimethylolpropionic acid into the polyurethane prepolymer to react for 2 hours, adding 2-hydroxyethyl disulfide, cooling to room temperature after reacting for 2 hours, adding triethylamine to react for 2-3 minutes, then dropwise adding 15mL of water, and simultaneously stirring at a high speed to obtain the self-repairing aqueous polyurethane emulsion.

7. The method for preparing a self-repairing aqueous polyurethane film according to claim 1, wherein the step 3) specifically comprises the following steps: pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene board, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃.

8. A self-healing aqueous polyurethane film obtained by the process according to any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of self-repairing material preparation, and particularly relates to a self-repairing waterborne polyurethane film and a preparation method thereof.

Background

In the processes of storage, transportation, sale and the like, the high polymer material is inevitably subjected to unexpected impact or scratch, and after the high polymer material is damaged, the original mechanical property of the high polymer material is damaged, so that the product value is damaged. The self-repairing material is a novel intelligent polymer material capable of self-diagnosing and self-repairing when the material is damaged, and the self-repairing polymer material is prepared for automatically repairing the mechanical property of the material after the material is damaged, eliminating the potential safety hazard of the material in the using process and prolonging the service life of the material, so that the polymer material which is longer in service life, more reliable in performance and more economical compared with the traditional polymer material is obtained.

At present, most self-repairing materials are externally-supported self-repairing materials, the matrix of the self-repairing materials does not have the self-repairing function, the self-repairing is realized through microcapsules carrying repairing agents, and the repairing effect and the repairing frequency of the self-repairing materials are low.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention aims to synthesize the waterborne polyurethane film with the self-repairing function, and the waterborne polyurethane film can self-repair and recover the mechanical property when being damaged.

In order to achieve the aim, the invention provides a preparation method of a self-repairing aqueous polyurethane film, which comprises the following steps:

1) dissolving polytetrahydrofuran diol in acetone, adding isophorone diisocyanate and a catalyst, and reacting to generate a polyurethane prepolymer;

2) sequentially adding N-methyl pyrrolidone, 2-dimethylolpropionic acid, 2-hydroxyethyl disulfide and triethylamine into the polyurethane prepolymer, and stirring for reaction to obtain a self-repairing aqueous polyurethane emulsion;

3) and pouring the self-repairing waterborne polyurethane emulsion on the polytetrafluoroethylene board and drying to obtain the self-repairing waterborne polyurethane film.

Furthermore, the amount of the reagent used for preparing the self-repairing aqueous polyurethane emulsion is 3g of polytetrahydrofuran diol, 2g of isophorone diisocyanate, 5ml of N-methylpyrrolidone, 0.275g of 2, 2-dimethylolpropionic acid, 0.3-0.9 g of 2-hydroxyethyl disulfide and 0.202g of triethylamine.

Furthermore, the amount of 2-hydroxyethyl disulfide in a reagent for preparing the self-repairing aqueous polyurethane emulsion is 0.6-0.75 g.

Further, the step 1) of dissolving polytetrahydrofuran diol in acetone comprises the following specific steps: the polytetrahydrofuran diol is dissolved in acetone after being pumped at 130 ℃.

Further, the reaction condition in the step 1) is 70-80 ℃ for 2 h.

Further, the specific reaction process of the self-repairing aqueous polyurethane emulsion obtained in the step 2) is as follows: adding N-methyl pyrrolidone and 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 2-hydroxyethyl disulfide, reacting for 2 hours, cooling to room temperature, adding triethylamine, reacting for 2-3 minutes, dropwise adding 15mL of water, and stirring at a high speed to obtain the self-repairing aqueous polyurethane emulsion.

Further, the step 3) of pouring the self-repairing aqueous polyurethane emulsion on the polytetrafluoroethylene board and drying specifically comprises the following steps: pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene board, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃.

The invention also provides the self-repairing aqueous polyurethane film prepared by the preparation method.

The invention has the beneficial effects that: the reversible disulfide bond is introduced, the covalent bond is easy to break and is recombined with other sulfur atoms based on the instability of the disulfide bond, and the self-repairing can be realized by using the redox reaction between the disulfide bond and the sulfydryl, so that the prepared waterborne polyurethane film has good self-repairing performance, can be self-repaired under certain conditions to recover the mechanical property when being damaged, and meanwhile, the waterborne polyurethane material has the advantages of good mechanical property, good stability, environmental protection, low VOC and the like.

Drawings

FIG. 1 is a particle size diagram of a self-repairing aqueous polyurethane emulsion prepared in an example of the present invention.

FIG. 2 is a graph showing the self-healing effect of a self-healing aqueous polyurethane film containing 0.75g (15%) of 2-hydroxyethyl disulfide according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.3-0.9 g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion according to the requirement, generally 4-5 ml, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

A self-repairing aqueous polyurethane film prepared by the preparation method.

TABLE 1 amount of reagents used to prepare self-healing aqueous polyurethane emulsions

Example 1

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.3g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

Example 2

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.45g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

Example 3

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.6g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

Example 4

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.75g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

Example 5

A preparation method of a self-repairing waterborne polyurethane film comprises the following steps:

1) 3g of polytetrahydrofuran diol is pumped at 130 ℃ and then dissolved in 20mL of acetone, 2g of isophorone diisocyanate and a catalyst are added, and the reaction is carried out for 2h at 70-80 ℃ to generate a polyurethane prepolymer;

2) adding 5mL of LN-methyl pyrrolidone and 0.275g of 2, 2-dimethylolpropionic acid, reacting for 2 hours, adding 0.9g of 2-hydroxyethyl disulfide, reacting for two hours, cooling to room temperature, adding 0.202g of triethylamine, reacting for 2-3 min, dropwise adding 15mL of water, and stirring at a high speed to obtain a self-repairing waterborne polyurethane emulsion;

3) pouring the self-repairing aqueous polyurethane emulsion on a polytetrafluoroethylene plate, drying for two hours at 40 ℃, adding a proper amount of the self-repairing aqueous polyurethane emulsion, and drying for 24 hours after the temperature is raised to 70 ℃ after two hours to obtain the self-repairing aqueous polyurethane film.

Example 6

The particle sizes of the self-repairing aqueous polyurethane emulsions prepared in examples 1 to 5 were measured by a dynamic light scattering scanner, and the results are shown in FIG. 1, wherein it can be seen that the self-repairing aqueous polyurethane emulsions containing 0.60g (12%) of 2-hydroxyethyl disulfide and 0.75g (15%) of 2-hydroxyethyl disulfide have smaller particle sizes and correspondingly better stability.

Example 7

The self-repairing performance test of the self-repairing waterborne polyurethane film prepared in the example 4 is carried out, and the test steps are as follows: wiping a blade with absolute ethyl alcohol, cutting the obtained polyurethane film by using the blade, aligning the cut of the cut polyurethane film, putting the polyurethane film into a 60 ℃ oven, and checking the self-repairing effect after 5min and 30min respectively. FIG. 2 is a graph showing the self-healing effect of a self-healing aqueous polyurethane film containing 0.75g (15%) of 2-hydroxyethyl disulfide.

The above-mentioned embodiments only express the embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.