CN110951038B - Novel polyurethane film and preparation thereof - Google Patents

Abstract

A novel polyurethane film and its preparation are provided. The invention adopts diisocyanate and polyester polyol as raw materials, adds a chain extender, uses oil bath for heating, adopts a prepolymerization method to prepare polyurethane prepolymer under the nitrogen protection atmosphere, and uses a polytetrafluoroethylene plate for tape casting film formation. The polyurethane film comprises the following components in percentage by mass: 12.4 to 18.9 percent of polyester polyol, 3.8 to 4.2 percent of diisocyanate, 0.5 to 0.7 percent of chain extender, 76.5 to 82.8 percent of organic solvent and 0.1 to 0.2 percent of catalyst. The polyurethane film has better tensile property than other polyurethane films, has yellowing resistance, good toughness and good ductility, and simultaneously has good hydrophobic property and aesthetic property. The method is simple and easy to operate, and has low equipment requirement.

Description

Novel polyurethane film and preparation thereof

Technical Field

The invention relates to a novel polyurethane film and a preparation method thereof, in particular to a novel polyurethane film and a preparation method thereof.

Background

With the increasingly wide application of polymer films in the field of packaging, the requirements on the film performance are more strict, and compared with the single performance of other films, the polyurethane has good comprehensive performance. Polyurethane is even called as the sixth plastic in the field of high polymer materials, and polyurethane products grow up in China. Compared with other polymer films, the polyurethane film has excellent tension, toughness, ageing resistance, wear resistance, impact resistance and the like. The processing technology is simple, and the cost can be reduced.

Polyurethane develops from 1937 to the present, China lags behind much in comparison with foreign countries in the aspect of polyurethane synthesis, most of raw materials adopt isocyanate materials with high toxicity, and the prepared film has the defects of yellowing and the like and influences the attractiveness. Therefore, the research on polyurethane is receiving much attention and will become a new hot spot.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a novel polyurethane film with high performance and exquisite appearance. Through comparative research on the existing polyurethane synthetic materials, the polyurethane film with good mechanical property, exquisite appearance and good hydrophobicity is prepared, and a method for preparing the film is provided.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a novel polyurethane film comprises the following components in percentage by mass:

12.4 to 18.9 percent of polyester polyol,

3.8 to 4.2 percent of diisocyanate

0.5 to 0.7 percent of chain extender,

76.5 to 82.8 percent of organic solvent

0.1 to 0.2 percent of catalyst

The novel polyurethane film is prepared by the following steps:

(1) preparing raw materials: and weighing the polyester polyol and the chain extender according to the weight, and dehydrating in an oven at the temperature of 80 ℃ for 12 hours.

(2) Reaction conditions are as follows: a250 ml round bottom three-neck flask which is respectively connected with a mechanical stirrer, a condenser and a nitrogen inlet and outlet is used as a polymerization reaction container, polyester polyol is added when the temperature of an oil bath rises to 60 ℃, diisocyanate is added when the temperature reaches 80 ℃, and the reaction is carried out in a nitrogen atmosphere. And adding a catalyst when the reaction is carried out for 1.5h, and adding a chain extender when the reaction is carried out for 2h to obtain the polyurethane prepolymer.

(3) Tape casting to form films

Pouring the polyurethane prepolymer into a beaker, pouring an organic solvent, dissolving the prepolymer by the solvent under magnetic stirring, pouring the dissolved product onto a polytetrafluoroethylene plate, and drying for 6 hours in an oven at 60 ℃ for film formation.

Moreover, the polyester polyol is poly adipic acid-1, 4-butanediol ester diol.

And, the chain extender is diethylene glycol.

Further, the diisocyanate is hexamethylene diisocyanate.

Further, the catalyst is dilaurate dibutyl butene.

And the organic solvent is N, N-dimethylformamide

The invention has the advantages and positive effects that:

(1) the polyurethane film prepared by the invention has good yellowing resistance and attractive appearance.

(2) The polyurethane film prepared by the invention has good toughness and ductility.

(3) The polyurethane film prepared by the invention has good hydrophobicity.

Drawings

FIG. 1 is a flow chart of the method of the present invention

Detailed Description

The present invention will be described in further detail with reference to the following embodiments, which are illustrative only and not limiting, and the scope of the present invention is not limited thereby.

Example 1

In this example, we performed experimental studies using the formulations in table 1:

TABLE 1 polyurethane film formulations

(1) Ingredients

Accurately weighing various raw materials by a balance. Note that: when hexamethylene diisocyanate is weighed, the hexamethylene diisocyanate needs to be weighed quickly and prevented from volatilizing, and poly adipic acid-1, 4-butanediol ester diol and diethylene glycol need to be subjected to water removal treatment.

(2) Prepolymerization process

A250 ml round bottom three-neck flask which is respectively connected with a mechanical stirrer, a condenser and a nitrogen inlet and outlet is used as a polymerization reaction vessel, polyester polyol is added when the temperature of an oil bath is raised to 60 ℃, diisocyanate is added when the temperature reaches 80 ℃, and the reaction is carried out in a nitrogen atmosphere. And adding a catalyst when the reaction is carried out for 1.5h, and adding a chain extender when the reaction is carried out for 2h to obtain the polyurethane prepolymer. Note that: water can not enter absolutely during the reaction process.

(3) Film formation

Pouring the polyurethane prepolymer into a beaker, pouring an organic solvent, dissolving the prepolymer by the solvent under magnetic stirring, pouring the dissolved product onto a polytetrafluoroethylene plate, and drying for 6 hours in an oven at 60 ℃ for film formation.

(4) Performance testing

Mechanical properties

Test specimens were prepared according to ASTM D-882 test standards and the films were tested for tensile strength and elongation at break. The test results are shown in Table 6.

② water contact angle

Test bars were prepared according to GB/T30693-2014 test standards and the films were tested for water contact angle. The test results are shown in Table 6.

Example 2

In this example, we performed experimental studies using the formulations in table 2:

TABLE 2 polyurethane film formulations

Other steps are the same as in the first embodiment.

Performance testing

Mechanical properties

Test specimens were prepared according to ASTM D-882 test standards and the films were tested for tensile strength and elongation at break. The test results are shown in Table 6.

② water contact angle

Test bars were prepared according to GB/T30693-2014 test standards and the films were tested for water contact angle. The test results are shown in Table 6.

Example 3

In this example, we performed experimental studies using the formulations in table 3:

TABLE 3 polyurethane film formulations

The other steps were the same as in examples 1 to 2.

Performance testing

Mechanical properties

Test specimens were prepared according to ASTM D-882 test standards and the films were tested for tensile strength and elongation at break. The test results are shown in Table 6.

② water contact angle

Test bars were prepared according to GB/T30693-2014 test standards and the films were tested for water contact angle. The test results are shown in Table 6.

Example 4

In this example, we performed experimental studies using the formulation in table 4:

TABLE 4 polyurethane film formulations

Other procedures the same as those of the examples 1 to 3

Mechanical properties

Test specimens were prepared according to ASTM D-882 test standards and the films were tested for tensile strength and elongation at break. The test results are shown in Table 6.

② water contact angle

Test bars were prepared according to GB/T30693-2014 test standards and the films were tested for water contact angle. The test results are shown in Table 6.

Example 5

In this example, we performed experimental studies using the formulation in table 5:

TABLE 5 polyurethane film formulations

Other procedures the same as those of the examples 1 to 4

Mechanical properties

Test specimens were prepared according to ASTM D-882 test standards and the films were tested for tensile strength and elongation at break. The test results are shown in Table 6.

② water contact angle

Test bars were prepared according to GB/T30693-2014 test standards and the films were tested for water contact angle. The test results are shown in Table 6.

TABLE 6 test results for finished products obtained in examples one to five

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept, and these changes and modifications are all within the scope of the present invention.

Claims (2)

1. A polyurethane film comprises the following components in percentage by mass:

12.4 to 16.9 percent of polyester polyol,

3.9 to 4.2 percent of diisocyanate

0.5 to 0.6 percent of chain extender,

78.5 to 82.8 percent of organic solvent

0.1 to 0.2 percent of catalyst;

the diisocyanate is hexamethylene diisocyanate; the polyester polyol is poly adipic acid-1, 4-butanediol glycol ester diol; the catalyst is dibutyltin dilaurate; the chain extender is diethylene glycol; the organic solvent is N, N-dimethylformamide;

the preparation method of the polyurethane film comprises the following steps:

the first step is as follows: putting polyester polyol and a chain extender into an oven at 80 ℃ for drying and melting for 48 hours, and weighing diisocyanate and a catalyst according to the weight parts;

the second step is that: adopting a 250ml round bottom three-neck flask which is respectively connected with a mechanical stirrer, a condenser and a nitrogen inlet and outlet as a polymerization reaction container, adding polyester polyol when the temperature is raised to 60 ℃, adding diisocyanate when the temperature reaches 80 ℃, and carrying out the whole reaction process in an oil bath at 80 ℃ and in a nitrogen atmosphere;

The third step: adding a catalyst when the reaction is carried out for 1.5 hours, and adding a chain extender when the reaction is carried out for 2 hours;

the fourth step: and pouring the reacted product into a beaker, adding an organic solvent for dissolving, pouring the dissolved solution onto a tetrafluoroethylene plate, putting the tetrafluoroethylene plate into a 60 ℃ oven for drying the solvent, and forming a film.

2. A method for preparing the polyurethane film of claim 1, which comprises:

the first step is as follows: putting polyester polyol and a chain extender into an oven at 80 ℃ for drying and melting for 48 hours, and weighing diisocyanate and a catalyst according to the parts by weight in claim 1;

the second step is that: adopting a 250ml round bottom three-neck flask which is respectively connected with a mechanical stirrer, a condenser and a nitrogen inlet and outlet as a polymerization reaction container, adding polyester polyol when the temperature is raised to 60 ℃, adding diisocyanate when the temperature reaches 80 ℃, and carrying out the whole reaction process in an oil bath at 80 ℃ and in a nitrogen atmosphere;

the third step: adding a catalyst when the reaction is carried out for 1.5 hours, and adding a chain extender when the reaction is carried out for 2 hours;

the fourth step: and pouring the reacted product into a beaker, adding an organic solvent for dissolving, pouring the dissolved solution onto a tetrafluoroethylene plate, putting the tetrafluoroethylene plate into a 60 ℃ oven for drying the solvent, and forming a film.

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