Polyimide solution composition and synthesis method thereof, polyimide film and method for improving binding force between polyimide film and inorganic layer

Abstract

The invention relates to a polyimide solution composition and a synthesis method thereof, a polyimide film and a method for improving binding force between the polyimide film and an inorganic layer, the composition comprises aromatic copolymerized polyamide acid, an organic solvent and a coupling agent, the aromatic copolymerized polyamide acid is formed by polymerizing aromatic dianhydride and aromatic diamine, the aromatic diamine also contains a third monomer, the third monomer contains a structure, and Ar is any one of phenyl, tetrahydrofuryl, tetrahydrothienyl or pyridyl. A diamine monomer with a specific structure is introduced into a polyimide main chain structure as a third monomer, a specific coupling agent is added as an interface regulator, and the polymerization process of polyimide slurry is controlled through a specific polymerization process, so that the polyimide film with high bonding force with inorganic layers such as SiNx or SiOx is manufactured.

Description

Technical Field

[0001] This invention relates to the field of polyimide slurry synthesis technology, specifically demonstrating polyimide solution compositions and their synthesis methods, polyimide films, and methods for improving the interlayer bonding strength between polyimide films and inorganic layers. Background Technology

[0002] Polyimide films are widely used in the electronics industry. Due to their excellent high-temperature stability and good electrical insulation properties, polyimide films are often used to manufacture high-temperature durable and highly stable semiconductor materials, such as integrated circuits, capacitors, inductors, and ultrasonic detectors.

[0003] In the field of OLED flexible display, polyimide is used as a substrate material due to its high heat resistance. However, since polyimide itself has poor water and oxygen barrier properties, an inorganic layer of SiOx or SiNx needs to be added as a water and oxygen barrier layer during the screen panel manufacturing process.

[0004] The interlayer bonding strength of multilayer structures is particularly important. Weak interlayer bonding strength will result in a lower production yield, which may lead to the risk of interlayer delamination during subsequent use. Therefore, it is especially important to improve the interlayer bonding strength between polyimide and inorganic layers. Summary of the Invention

[0005] The purpose of this invention is to design a polyimide slurry that can have a high bonding force with SiNx or SiOx, thereby improving the bonding force between the polyimide film and the inorganic layer.

[0006] The technical solution is as follows: In a first aspect, the present invention provides a polyimide solution composition comprising an aromatic copolyamic acid, an organic solvent, and a coupling agent, wherein the aromatic copolyamic acid is polymerized from an aromatic dianhydride and an aromatic diamine, and wherein the aromatic diamine further contains a third monomer comprising the structure shown in general formula (1). (1) Ar is any one of phenyl, tetrahydrofuranyl, tetrahydrothiophenyl, or pyridyl.

[0007] In addition, the above embodiments of the present invention may also have the following additional technical features: According to one embodiment of the present invention, the coupling agent is a silane coupling agent capable of reacting with aromatic copolyamic acid.

[0008] The coupling agent is selected from KH550 or KH560, and its addition amount is 0.01% to 5% of the total mass of the composition.

[0009] According to one embodiment of the present invention, the amount of the third monomer added is 0.1% to 30% of the total molar amount of aromatic diamine.

[0010] Preferably, the amount of the third monomer added is 1% to 15% of the total molar amount of aromatic diamine.

[0011] More preferably, the amount of the third monomer added is 1% to 5% of the total molar amount of aromatic diamine.

[0012] According to one embodiment of the present invention, the organic solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0013] In a second aspect, the present invention provides a method for synthesizing the polyimide solution composition as described in the first aspect, comprising the following steps: Dissolve the aromatic diamine monomer in an organic solvent; After stirring evenly, the third monomer is added. After reacting for a period of time, aromatic dianhydride monomers are added in steps to continue polymerization. The reaction temperature is 30℃ to 110℃, and the reaction time is more than 2 hours; Add coupling agent and continue stirring to mix; The polyimide solution composition was obtained by filtration.

[0014] Thirdly, the present invention provides a polyimide film, which is made by coating and baking the polyimide solution composition described in the first aspect, wherein the baking temperature is from 50°C to 470°C.

[0015] Fourthly, the present invention also provides a method for improving the interlayer adhesion between a polyimide film and an inorganic layer, comprising: Introduce a third monomer as described in the first aspect into the polyamic acid composition; Add a coupling agent as described in the first aspect; The slurry is prepared by the synthesis method described in the second aspect and formed into a film on the surface of the inorganic layer.

[0016] Compared with existing technologies, the advantages of this invention are as follows: a diamine monomer with a specific structure is introduced as a third monomer into the polyimide backbone structure, and a specific coupling agent is added as an interface modifier. The polymerization process of the polyimide slurry is controlled through a specific polymerization process. This method produces polyimide films with high adhesion to inorganic layers such as SiNx or SiOx, which can be used as substrate materials for organic light-emitting diodes (OLEDs), helping to improve product yield and stability. Attached Figure Description

[0017] Figure 1A comparative graph showing the adhesive strength test results of polyimide film A, polyimide film B, and polyimide film C. Figure 2 Comparison of adhesive strength tests for polyimide films D, E, and F. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention provides a polyimide solution composition comprising an aromatic copolyamic acid, an organic solvent, and a coupling agent. The aromatic copolyamic acid is polymerized from aromatic dianhydrides and aromatic diamines. Both aromatic dianhydrides and aromatic diamines are commonly used dianhydride and diamine monomers. For example, aromatic dianhydrides can be selected from pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, etc., and aromatic diamines can be selected from p-phenylenediamine, 4,4'-biphenylenediamine, and 4,4'-diaminodiphenyl ether, etc.

[0020] The aromatic diamine also contains a third monomer, which is also a diamine monomer and contains an aromatic imine group. In other words, the third monomer possesses... The general formula structure is , where Ar is any one of phenyl, tetrahydrofuranyl, tetrahydrothiophenyl or pyridyl.

[0021] The chemical structural formula of the third monomer is as follows: 1A (containing tetrahydrothiophene), 2A (containing phenyl), 3A (tetrahydrofuranyl), and 4A (pyridyl). , , , .

[0022] The coupling agent is a silane-based coupling agent that can react with aromatic copolymer polyamic acid, such as KH550 or KH560. The chemical structural formulas of KH550 and KH560 are shown in (1) and (2) respectively. , .

[0023] The amount of coupling agent added is 0.01% to 5% of the total mass of the polyimide composition; the amount of the third monomer added is 1% to 15% of the total molar mass of the aromatic diamine, preferably 0.05% to 5%, more preferably 0.1% to 3%.

[0024] The organic solvent can be N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0025] Example 1 ① Synthesis of polyimide slurry (PAA-1) To a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser, add 32 g of N-methylpyrrolidone (NMP) organic solvent; then add p-phenylenediamine monomer (2.5 g) and stir until completely dissolved; then add 0.4 g of the third monomer 2A (Ar is phenyl), heat to 60 °C and react for 1 hour; then add 4,4'-biphenyl ether dianhydride (BPDA, 6.0 g) in three portions and continue stirring for 2 hours; finally, filter the slurry using a 0.45 μm filter membrane.

[0026] ② Preparation of polyimide films PAA-1 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, polyimide film A was obtained.

[0027] Example 2 ① Synthesis of polyimide slurry (PAA-2) 32 g of N-methylpyrrolidone (NMP) organic solvent was added to a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser. Then, 2.5 g of p-phenylenediamine monomer was added and stirred until completely dissolved. 0.4 g of the third monomer 2A (Ar is phenyl) was added, and the mixture was heated to 60 °C and reacted for 1 hour. Subsequently, 6.0 g of 4,4'-biphenyl ether dianhydride (BPDA) was added in three portions and the mixture was stirred for 2 hours. 0.5% of the total mass of the composition of silane coupling agent KH550 was added and the mixture was stirred for 30 minutes. Finally, the slurry was filtered through a 0.45 μm filter membrane.

[0028] ② Preparation of polyimide films PAA-2 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, polyimide film B was obtained.

[0029] Example 3 ① Synthesis of polyimide slurry (PAA-3) Add 32 g of N-methylpyrrolidone (NMP) organic solvent to a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser; then add p-phenylenediamine monomer (2.5 g) and stir until completely dissolved; then add 4,4'-biphenyl ether dianhydride (BPDA, 6.2 g) in three portions and continue stirring for 2 hours; finally filter through a 1-micron pore membrane.

[0030] ② Preparation of polyimide films PAA-3 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, polyimide film C was obtained.

[0031] Example 4 ① Synthesis of polyimide slurry (PAA-4) Add 32 g of N-methylpyrrolidone (NMP) organic solvent to a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser; then add p-phenylenediamine monomer (2.5 g) and stir until completely dissolved; then add 0.4 g of the third monomer 1A (Ar is tetrahydrothiophene), heat to 60 °C and react for 1 hour, then add 4,4'-biphenyl ether dianhydride (BPDA, 6.0 g) in three portions and continue stirring for 2 hours; finally filter through a 0.45 μm filter membrane.

[0032] ② Preparation of polyimide films PAA-4 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, polyimide film D was obtained.

[0033] Example 5 ① Synthesis of polyimide slurry (PAA-5) Add 32 g of N-methylpyrrolidone (NMP) organic solvent to a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser; then add p-phenylenediamine monomer (2.5 g) and stir until completely dissolved; then add 0.4 g of the third monomer 3A (Ar is tetrahydrofuranyl), heat to 60 °C and react for 1 hour, then add 4,4'-biphenyl ether dianhydride (BPDA, 6.0 g) in three portions and continue stirring for 2 hours; finally filter through a 0.45 μm filter membrane.

[0034] ② Preparation of polyimide films PAA-5 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, polyimide film E was obtained.

[0035] Example 6 ① Synthesis of polyimide slurry (PAA-6) Add 32 g of N-methylpyrrolidone (NMP) organic solvent to a dry 150 ml three-necked flask equipped with a magnetic stirrer and a condenser; then add p-phenylenediamine monomer (2.5 g) and stir until completely dissolved; then add 0.4 g of the third monomer 4A (Ar is pyridyl), heat to 60 °C and react for 1 hour, then add 4,4'-biphenyl ether dianhydride (BPDA, 6.0 g) in three portions and continue stirring for 2 hours; finally filter through a 0.45 μm filter membrane.

[0036] ② Preparation of polyimide films PAA-6 slurry was coated onto a substrate with a SiOx layer by a blade coating method. The wet film thickness was 60 μm, the length was 20 cm, and the width was 10 cm. The coated substrate was placed in an oven with programmable temperature rise and baked in a nitrogen atmosphere according to the following procedure: slowly rise from 50°C to 300°C (1 hour), and then rise to 450°C (0.5 hours) for imidization. After natural cooling, a polyimide film F was obtained.

[0037] The above-mentioned scheme of Example 3 is formed by the polymerization of conventional dianhydride and diamine; the schemes of Examples 1, 4, 5 and 6 are formed by the polymerization of conventional dianhydride, diamine and a third monomer containing a specific structure; the scheme of Example 2 is formed by the polymerization of conventional dianhydride, diamine, a third monomer containing a specific structure and a silane coupling agent.

[0038] Performance comparison: The thicknesses of the polyimide films A, B, C, D, E, and F prepared above are normally controlled between 5 and 200 μm. During performance testing, the thicknesses of all four films are maintained at 10 μm to avoid inconsistencies in film thickness affecting the test results. The test strip is 2 cm wide, and the adhesive force is the ratio of the peel force to the strip width at 180° peel angle.

[0039] The adhesive strength of polyimide films A, B, C, D, E, and F was tested using a universal testing machine. The test results are shown in Table 1 and attached table. Figure 1 and attached Figure 2 As shown: Table 1 As can be seen from the table above, adding the third monomer of the present invention to polyamic acid can effectively improve the adhesion strength between the polyimide film material and the SiOx substrate. Specifically, the adhesion strength between the polyimide film with added diamine 2A and the inorganic layer can be increased from 0.05 N / cm to 0.7 N / cm, while adding a coupling agent can increase the bonding force between the polyimide film and the SiOx inorganic layer to 1.20 N / cm.

[0040] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A polyimide solution composition comprising an aromatic copolyamic acid, an organic solvent, and a coupling agent, wherein the aromatic copolyamic acid is polymerized from an aromatic dianhydride and an aromatic diamine, characterized in that, The aromatic diamine also contains a third monomer, which has the structure shown in general formula (1). （1） Ar is any one of phenyl, tetrahydrofuranyl, tetrahydrothiophenyl, or pyridyl.

2. The polyimide solution composition according to claim 1, characterized in that, The coupling agent is a silane-based coupling agent capable of reacting with aromatic copolyamic acid.

3. The polyimide solution composition according to claim 2, characterized in that, The coupling agent is selected from KH550 or KH560, and its addition amount is 0.01% to 5% of the total mass of the composition.

4. The polyimide solution composition according to claim 1, characterized in that, The amount of the third monomer added is 0.1% to 30% of the total molar amount of aromatic diamine.

5. The polyimide solution composition according to claim 4, characterized in that, The amount of the third monomer added is 1% to 15% of the total molar amount of aromatic diamine.

6. The polyimide solution composition according to claim 5, characterized in that, The amount of the third monomer added is 1% to 5% of the total molar amount of aromatic diamine.

7. The polyimide solution composition according to claim 1, characterized in that, The organic solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

8. A method for preparing the polyimide solution composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: Dissolve the aromatic diamine monomer in an organic solvent; After stirring evenly, the third monomer is added. After reacting for a period of time, aromatic dianhydride monomers are added in steps to continue polymerization. The reaction temperature is 30℃ to 110℃, and the reaction time is more than 2 hours; Add coupling agent and continue stirring to mix; The polyimide solution composition was obtained by filtration.

9. A polyimide film, characterized in that, The polyimide solution composition of claim 1 is prepared by coating and baking, wherein the baking temperature is from 50°C to 470°C.

10. A method for improving the interlayer bonding strength between a polyimide film and an inorganic layer, characterized in that, include: Introducing the third monomer as described in claim 1 into the polyamic acid composition; Add the coupling agent as described in claim 1; The slurry was prepared by the synthesis method described in claim 8 and formed into a film on the surface of the inorganic layer.

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