CN116478402A - Transparent polyimide with high heat resistance and low expansion and preparation method thereof - Google Patents

Abstract

The invention discloses a transparent polyimide with high heat resistance and low expansion and a preparation method thereof, wherein 2.2417-4.6188g of dianhydride compound, 2.7357-3.2023g of diamine compound, 22-40g of N-methylpyrrolidone, 5.1g of acetic anhydride and 2.6g of triethylamine are mixed; the dianhydride compound comprises one or more of flexible dianhydride, alicyclic dianhydride, rigid dianhydride and amide-containing dianhydride; the diamine compound comprises one or more of diamine containing fluorine/carbonyl, diamine containing amide or condensed ring structure, and crosslinked diamine. Through designing a molecular structure, the linearity and rigidity of a molecular chain are changed, and meanwhile, a hydrogen bond and a crosslinking structure are introduced, so that the material has higher glass transition temperature, lower expansion coefficient and better optical performance and mechanical performance.

Description

Transparent polyimide with high heat resistance and low expansion and preparation method thereof

Technical Field

The invention relates to the technical field of transparent polyimide materials, in particular to a high-heat-resistance low-expansion transparent polyimide and a preparation method thereof.

Background

Modern flexible packaging technology requires cover plate materials that have good optical properties (e.g., high transmittance, low yellowness index, low haze, etc.), higher heat resistance (high glass transition temperature), and higher dimensional stability (low coefficient of linear thermal expansion) while being flexible. Transparent polyimide (CPI) materials are of great interest because of their good flexibility, good optical properties and good mechanical properties.

However, the conventional transparent polyimide material adopts a large-volume fluorine-containing group, so that the intermolecular acting force is low, the linear expansion coefficient is high, and the material is easy to strip from a matrix due to thermal expansion and cold contraction in high-low temperature cyclic use, so that flexible packaging is not facilitated.

Disclosure of Invention

The invention aims to provide the transparent polyimide with high heat resistance and low expansion, and the technical problems in the background technology are solved by designing a molecular structure, changing the linearity and rigidity of a molecular chain, simultaneously introducing a hydrogen bond and a crosslinking structure, enabling a material to have a higher glass transition temperature and a lower expansion coefficient.

The technical scheme of the invention provides high heat-resistant low-expansion transparent polyimide, which comprises the following components in parts by weight: 2.2417-4.6188g of dianhydride compound, 2.7357-3.2023g of diamine compound, 22-40g of N-methylpyrrolidone, 5.1g of acetic anhydride and 2.6g of triethylamine;

the dianhydride compound comprises one or more of flexible dianhydride, alicyclic dianhydride, rigid dianhydride and amide-containing dianhydride; the diamine compound comprises one or more of diamine containing fluorine/carbonyl, diamine containing amide or condensed ring structure, and crosslinked diamine.

In a preferred embodiment, the flexible dianhydride content is 20-80%, the alicyclic dianhydride content is 20-80%, and the rigid and amide-containing dianhydride content is 5-30%; the diamine content of fluorine/carbonyl group is 40-80%, the diamine content of amide or condensed ring structure is 10-60%, and the cross-linking diamine content is 0-10%

In a preferred embodiment, the flexible dianhydride comprises 4,4'- (hexafluoroisopropenyl) diphthalic anhydride (6 FDA), and the cycloaliphatic dianhydride comprises 1,2,3, 4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,4, 5-cyclohexanedicarboxylic acid dianhydride (HPMDA), rigid and amide-containing dianhydride N, N' - (2, 2-bis (trifluoromethyl) - [1,1 '-biphenyl ] -4,4' -diyl) bis (1, 3-bisoxo-1, 3-dihydroisobenzofuran-5-carboxamide) (TA-TFMB).

In a preferred embodiment, the fluorine/carbonyl-containing diamine comprises 2,2 '-bis (trifluoromethyl) diaminobiphenyl (TFMB), 9-bis (4-amino-3-fluorophenyl) fluorene (BAFL), the amide-or fused ring structure-containing diamine comprises 3', 4-Diaminobenzanilide (DABA), and the crosslinked diamine comprises 1,3, 5-tris (4-aminophenyl) benzene.

A preparation method of transparent polyimide with high heat resistance and low expansion comprises the following preparation steps:

s1: 2.7357-3.2023g of diamine compound and 22-40g of N-methylpyrrolidone are added into a reaction vessel filled with nitrogen, and stirred for dissolution;

s2: then adding 2.2417-4.6188g of dianhydride compound into the solution obtained in the step S1, and carrying out polymerization reaction for 24 hours at the temperature of 0 ℃ to form transparent polyamic acid precursor solution;

s3: adding 5.10g of acetic anhydride and 2.60g of triethylamine into the body solution, and continuously stirring for 12 hours to perform chemical imidization to obtain a polyimide solution;

s4: pouring the polyimide solution into methanol to separate out white filiform precipitate, filtering out the filiform precipitate, washing with methanol twice, and drying to obtain polyimide powder;

s5: the polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

The technical scheme of the invention has the beneficial effects that:

through designing a molecular structure, the linearity and rigidity of a molecular chain are changed, and meanwhile, a hydrogen bond and a crosslinking structure are introduced, so that the material has higher glass transition temperature, lower expansion coefficient and better optical performance and mechanical performance.

Drawings

FIG. 1 is a graph showing the results of the tests in examples 2,4 and 5 of the present invention,

FIG. 2 is a graph showing the results of the tests in examples 1,3, 6 and 7 of the present invention.

Detailed Description

The invention will be described in further detail with reference to the drawings and the detailed description. The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Example 1

3.2023g of a diamine compound TFMB,30g of N-methylpyrrolidone, was charged into a reaction vessel to which nitrogen gas was introduced, and dissolved by stirring. 4.4424g of dianhydride compound 6FDA was added in sequence and polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, which was tested for an intrinsic viscosity of 0.95dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate was filtered off and washed twice with methanol, and dried to obtain polyimide powder.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 2

3.2023g of a diamine compound TFMB,22g of N-methylpyrrolidone, was charged into a reaction vessel to which nitrogen was introduced, and dissolved by stirring. 2.2417g of dianhydride compound HPMDA was added in sequence, and polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, which was tested for intrinsic viscosity of 0.86dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 3

To a reaction vessel which had been purged with nitrogen, 1.6012g of a diamine compound TFMB and 1.1363g of a diamine compound DABA (total 2.7357), 40g of N-methylpyrrolidone were added, and dissolved by stirring. 2.2212g of dianhydride compound 6FDA and 0.9806g of dianhydride compound CBDA (3.2018) were sequentially added and polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, which was tested for intrinsic viscosity of 1.10dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 4

3.2023g of a diamine compound TFMB,30g of N-methylpyrrolidone, was charged into a reaction vessel to which nitrogen gas was introduced, and dissolved by stirring. 1.1209g of the dianhydride compound HPMDA and 3.3423g of the dianhydride compound TA-TFMB (4.4637) were sequentially added, polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, and tested for an intrinsic viscosity of 0.98dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 5

1.6012g of a diamine compound TFMB and 1.7422g of a diamine compound BAFL (2.8034), 22g of N-methylpyrrolidone were charged into a reaction vessel to which nitrogen was introduced, and dissolved by stirring. 1.1209g of the dianhydride compound HPMDA and 3.3423g of the dianhydride compound TA-TFMB (4.4637) were sequentially added, polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, and tested for an intrinsic viscosity of 0.88dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 6

1.6012g of a diamine compound TFMB and 1.7422g of a diamine compound BAFL ((2.8034)) were charged into a reaction vessel to which nitrogen gas was introduced, and 26g of N-methylpyrrolidone was dissolved by stirring. 2.2212g of dianhydride compound 6FDA and 0.9806g of dianhydride compound CBDA (3.2018) were sequentially added and polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, which was tested for an intrinsic viscosity of 1.09dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

Example 7

Into a reaction vessel which had been purged with nitrogen gas were charged 1.6012g of a diamine compound TFMB and 1.3938g of a diamine compound BAFL and 0.7029g of a diamine compound 1,3, 5-tris (4-aminophenyl) benzene (2.995), 26g of N-methylpyrrolidone, and dissolved by stirring. 2.2212g of dianhydride compound 6FDA, 2.0054g of dianhydride compound TA-TFMB and 0.3922g of dianhydride compound CBDA (4.6188) were sequentially added and polymerized at 0℃for 24 hours to form a transparent polyamic acid (PAA) solution, which was tested for intrinsic viscosity of 1.03dL/g.

To this precursor solution, 5.10g of acetic anhydride and 2.60g of triethylamine were added, and the mixture was stirred for 12 hours to effect chemical imidization, thereby obtaining a polyimide solution. This solution was poured into methanol, and a white fine-line precipitate was precipitated. The filiform precipitate is filtered off and washed twice with methanol and dried. Polyimide powder was obtained.

The polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.

The transparent polyimide films prepared in examples 1 to 7 were subjected to performance test, and the results are shown in Table 1 below:

TABLE 1

In the table: BAFL50 means a material BAFL molar ratio of 50, the others being the same.

And drawing the results into a columnar body to obtain a comparison chart 1 and a comparison chart 2, and analyzing the results as follows:

(1) By analysis and comparison of fig. 1, example 4 has a significant improvement in Tg and CTE over example 2, since the TA-TFMB group introduced in example 4 contains an amide bond and a rigid structure, increasing the intermolecular interactions, affecting the Tg and CTE properties of the product. Example 5 has a significant increase in Tg compared to example 4 due to the introduction of the bulky side groups of BAFL, but also has an increase in CTE due to the introduction of the bulky side groups.

(2) By analysis comparing fig. 2, examples 6 and 3 show significant improvements in Tg and CTE over example 1, which benefit from the incorporation of CBDA and DABA monomers, which increase the linear stiffness of the molecular chains due to the incorporation of CBDA and DABA, while increasing the amide bond content of the molecular chains, increasing the hydrogen bond content of the molecular chains, resulting in a decrease in CTE, an increase in Tg, and an increase in CTE over example 3 due to the incorporation of bulk pendant BAFL, an increase in molecular chain spacing, resulting in an increase in CTE. Example 7 compares to examples 6 and 3, and has better properties than examples 6 and 3 because it introduces a cross-linking structure in the molecular chain, allowing cross-links to form between the molecular chains, increasing the chain-to-chain interactions.

It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art and which are included in the embodiments of the present invention without the inventive step, are intended to be within the scope of the present invention. Structures, devices and methods of operation not specifically described and illustrated herein, unless otherwise indicated and limited, are implemented according to conventional means in the art.

Claims (5)

1. The transparent polyimide with high heat resistance and low expansion is characterized by comprising the following components in parts by weight: 2.2417-4.6188g of dianhydride compound, 2.7357-3.2023g of diamine compound, 22-40g of N-methylpyrrolidone, 5.1g of acetic anhydride and 2.6g of triethylamine;

the dianhydride compound comprises one or more of flexible dianhydride, alicyclic dianhydride, rigid dianhydride and amide-containing dianhydride; the diamine compound comprises one or more of diamine containing fluorine/carbonyl, diamine containing amide or condensed ring structure, and crosslinked diamine.

2. The transparent polyimide of claim 1, wherein the flexible dianhydride content is 20-80%, the alicyclic dianhydride content is 20-80%, and the rigid and amide-containing dianhydride content is 5-30%; the content of diamine containing fluorine/carbonyl is 40-80%, the content of diamine containing amide or condensed ring structure is 10-60%, and the content of cross-linking diamine is 0-10%.

3. The transparent polyimide of claim 1, wherein the flexible dianhydride comprises 4,4'- (hexafluoroisopropenyl) diphthalic anhydride (6 FDA), the cycloaliphatic dianhydride comprises 1,2,3, 4-cyclobutane tetracarboxylic dianhydride (CBDA), 1,2,4, 5-cyclohexane tetracarboxylic dianhydride (HPMDA), and the rigid and amide-containing dianhydride N, N' - (2, 2-bis (trifluoromethyl) - [1,1 '-biphenyl ] -4,4' -diyl) bis (1, 3-dioxy-1, 3-dihydroisobenzofuran-5-carboxamide) (TA-TFMB).

4. The transparent polyimide of claim 1, wherein the diamine comprises 2,2 '-bis (trifluoromethyl) diaminobiphenyl (TFMB), 9-bis (4-amino-3-fluorophenyl) fluorene (BAFL), the diamine comprising an amide or fused ring structure comprises 3', 4-Diaminobenzanilide (DABA), and the cross-linked diamine comprises 1,3, 5-tris (4-aminophenyl) benzene.

5. The method for producing a transparent polyimide having high heat resistance and low expansion according to any one of claims 1 to 4, comprising the steps of:

s1: 2.7357-3.2023g of diamine compound and 22-40g of N-methylpyrrolidone are added into a reaction vessel filled with nitrogen, and stirred for dissolution;

s2: then adding 2.2417-4.6188g of dianhydride compound into the solution obtained in the step S1, and carrying out polymerization reaction for 24 hours at the temperature of 0 ℃ to form transparent polyamic acid precursor solution;

s3: adding 5.10g of acetic anhydride and 2.60g of triethylamine into the body solution, and continuously stirring for 12 hours to perform chemical imidization to obtain a polyimide solution;

s4: pouring the polyimide solution into methanol to separate out white filiform precipitate, filtering out the filiform precipitate, washing with methanol twice, and drying to obtain polyimide powder;

s5: the polyimide powder is dissolved in N, N-dimethylformamide to form a solution with the mass fraction of 18 percent, the solution is coated on the surface and the inside of a clean glass plate, the solution is placed in an oven, the solvent is volatilized at 80 ℃ for 12 hours, the temperature is kept at 200 ℃ for 1 hour, and then the temperature is raised to 300 ℃ and kept for 1 hour, so that the transparent polyimide film is obtained.