TWI864938B - Polyimide film and laminate made of the same - Google Patents

Abstract

The present invention is a polyimide film and a laminate thereof, particularly a polyimide film and a laminate thereof having 3,3',4,4'-biphenyltetracarboxylic anhydride (BPDA) component; pyromellitic anhydride (PMDA) component; p-phenylenediamine (p-PDA) component; 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) component and 4,4'-diaminodiphenyl ether (ODA) component; and using BPDA and PDA as copolymer chain segments, so that the polyimide film and the laminate thereof have good thermal properties, mechanical properties and adhesion.

Description

Polyimide film and laminate made using the same

The present invention is a polyimide film and a laminate made of the film, particularly a polyimide film and laminate made of 3,3',4,4'-biphenyltetracarboxylic anhydride (BPDA); pyromellitic anhydride (PMDA); p-phenylenediamine (p-PDA); 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) and 4,4'-diaminodiphenyl ether (ODA); and BPDA and PDA as copolymer segments, so that the film and laminate have good thermal properties, mechanical properties and adhesion.

A flexible circuit board is a base layer between a metal layer and a polyimide layer. Most flexible circuit boards have a plastic layer between the metal layer and the polyimide layer as a medium between the two layers. In recent years, as flexible circuit design has developed towards fine lines, the thickness of the metal layer has become thinner and thinner, so a laminate with a polyimide layer and a metal layer directly connected has been developed.

Generally speaking, when a polyimide layer is bonded to a metal layer, a plastic polyimide layer can be attached to the polyimide layer as a bonding medium. However, the bonding process with the metal requires high temperature hot pressing. This manufacturing method is difficult to produce a thin polyimide layer and metal layer integral body. Another method is to use direct metallization to bond the metal layer to the polyimide layer. However, common polyimide is difficult to produce bonding force with the metal layer, and surface treatment is required before metallization to have a certain degree of bonding with the metal.

TWI695865 proposes a method to improve the adhesion after metallization. The method is to apply a layer of primer on the polyimide film to improve the adhesion between the metal layer and the polyimide layer. However, due to the poor thermal properties of the primer coating, the thermal properties of the entire polyimide film will be reduced, and the primer layer is prone to adhesion, making subsequent processing difficult.

Therefore, the present invention proposes a polyimide film that can provide good adhesion without primer coating, which will effectively improve the adhesion of the polyimide film after metallization, and can still maintain adhesion greater than 0.5kgf/cm after baking at aging conditions of 150°C for 24 hours.

The present invention is a polyimide film, which is a copolymerized polyimide formed by dianhydride and dian acid, wherein the dianhydride includes 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) accounting for 60-80 mol% of the total dianhydride mole number and pyromellitic anhydride (PMDA) accounting for 20-40 mol% of the total dianhydride mole number; the diamine includes p-phenylenediamine (p-PDA) accounting for 10-40 mol% of the total diamine mole number, and 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB ) accounts for 30-60 mol% of the total diamine molar number and 4,4'-diaminodiphenyl ether (ODA) accounts for 10-40 mol% of the total diamine molar number; wherein the copolymerized polyimide has a copolymer chain segment composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA), and the copolymer chain segment accounts for 25-40% of the total molar number of the polyimide, so that the thermal expansion coefficient CTE of the polyimide film is less than 15ppm/℃, and the Young's modulus is greater than 7GPa.

Polyimide film preparation

The polyimide film is prepared by chemical cyclization or thermal cyclization of copolymerized polyamide, wherein the copolymerized polyamide is obtained by polymerization of dianhydride and diamine, wherein the dianhydride comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) accounting for 60-80 mol% of the total dianhydride and pyromellitic anhydride (PMDA) accounting for 20-40 mol% of the total dianhydride; and the diamine comprises p-phenylenediamine (p-PDA) accounting for 10-40 mol% of the total diamine, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) accounting for 30-60 mol% of the total diamine, and 4,4'-diaminodiphenyl ether (ODA) accounting for 10-40 mol% of the total diamine. The copolymer polyimide must have a copolymer chain segment composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA).

The implementation method is to use BPDA and PDA to react in a solvent for 1 to 3 hours to form a copolymer chain segment. The molar number of the copolymer chain segment must account for 25% to 40% of the total molar number to ensure better thermal properties.

As a solvent, dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), N,N-dimethylformamide (DMF) can be used to prepare the polyimide component. The present invention uses dimethylacetamide as a solvent.

After the polymerization of the copolymer chain segments of BPDA and PDA is completed, the remaining diamine is added. The diamine can be added in full or in part to form the second copolymer chain segment or the third copolymer chain segment.

The diamine can be any one of mTB, ODA, and PDA. After adding the diamine, PMDA or BPDA is added to adjust the total anhydride molar number to the total diamine molar number ratio to 0.95 or more, and then stirred for at least 1 hour, preferably more than 2 hours. Then, a small amount of BPDA or PMDA is used to adjust the viscosity. Finally, the solution is adjusted to 100,000cps~600,000cps, preferably 150,000~400,000cps. At this time, the solid content of the solution can be between 10~25wt% to complete the preparation of the polyimide precursor.

In addition, the above-mentioned polyimide precursor can be added with inorganic material particles or organic material particles for the purpose of improving various properties such as winding, sliding, thermal conductivity, high hardness, color, etc. The inorganic material particles can be silicon oxide, boron nitride, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, calcium phosphate, etc.

The organic material particles can be tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP), polyimide (PI).

The average particle size of inorganic material particles and organic material particles is usually 0.01um to 100um, preferably 0.03um to 10um, and more preferably 0.05um to 5um.

The addition amount of inorganic material particles and organic material particles is 0.5~10%, preferably 1~3%.

The polyimide precursor (copolymerized polyamide) of the above segment can be imidized to prepare polyimide membrane by thermal cyclization and chemical cyclization.

The thermal cyclization method is a cyclization method that does not use a dehydrating agent or a catalyst. The copolymerized polyimide is mixed with a solvent, the viscosity is adjusted to 8,000~20,000cps, and then coated on a glass or metal carrier. The mixture is heated to a temperature range of 350~400 degrees and baked for a long time. After a baking time of 1~8 hours, a polyimide film is obtained.

The chemical cyclization method is to mix the copolymerized polyamine with a solvent to adjust the viscosity, and then add a catalyst and a dehydrating agent for chemical cyclization, wherein the dehydrating agent can be acetic anhydride or benzoic anhydride, and acetic anhydride is selected as the dehydrating agent in the present invention; wherein the catalyst can be pyridine, 3-methylpyridine, 2-methylpyridine, 4-methylpyridine, isoquinoline, quinoline, triethylamine, wherein pyridine, 3-methylpyridine, 2-methylpyridine, 4-methylpyridine are preferably selected, and 3-methylpyridine is selected as the catalyst in the present invention.

The above catalysts and dehydrating agents can be used alone or mixed with solvents for dilution.

Add it to the mixed liquid, stir the mixed liquid with dehydrating agent and catalyst evenly, and then use a centrifugal degasser to degas. Apply the degassing solution to the glass plate and then use a scraper to apply it. The gap of the scraper can be adjusted according to the required thickness. Place the coated sample in a baking oven at 40℃~120℃ for 10~40 minutes, preferably at 60℃~100℃ for 20~30 minutes, then bake at 170oC~200℃ for 10 minutes, then bake at 230℃~280℃ for 5~25 minutes, preferably at 240~260℃ for 10~20 minutes, and finally bake at 330℃~400℃ for 10~30 minutes as the final treatment, preferably at 350℃~370℃ for 15~20 minutes.

In addition to glass, metal plates can also be used as substrates in the above film-making process. When using metal plates to make the polyimide film, it needs to be removed from the metal plate after being baked and dried at a temperature range of 40℃~120C℃. The semi-dried film after removal is fixed on the metal frame, and then the temperature is raised to 170℃ and baked for 20 minutes, and then the temperature is raised to 350℃ and baked for 20 minutes as the final treatment to obtain the polyimide film.

Laminate production

The method of laminated plate includes: forming a nickel metal layer on the surface of a polyimide film by electroless plating, so that the nickel metal layer is in contact with the polyimide film; and after the nickel metal layer is formed, heat treatment is performed, and then a copper layer is formed thereon by electrolytic plating.

In the present invention, the nickel layer is formed by chemical plating on one or both sides of the polyimide substrate. As for the chemical plating, it can be a known chemical plating method and is not particularly limited. In addition, as for the specific example of chemical plating, the polyimide membrane can also be subjected to surface hydrophilization treatment first, and the surface treatment known in the technical field can be adopted here, and it is not limited here.

The surface treatment used in the present invention uses a roll-to-roll plasma treatment machine (model R2RP03) purchased from Creating Nano Technologies Inc. to perform surface hydrophilization treatment on the polyimide membrane. The operating conditions are described as follows.

The polyimide film is fixed on the unwinding reel and connected to the film guide. The chamber is closed and nitrogen (N ₂ ) is introduced. The power is turned on to start the vacuum. After the machine is preheated, it can enter the process stage. The tension is set to 2kg, the working pressure is 300mTorr, and the power is 10kW. The gas type and flow rate are adjusted. There are four types of gases: nitrogen (N ₂ ), oxygen (O ₂ ), carbon tetrafluoride (CF ₄ ) and argon (Ar). They can be combined as needed. The total gas flow rate is controlled between 1900sccm and 2700sccm. The length of the plasma zone is 11m. The processing time can be controlled by adjusting the machine line speed, which ranges from 0.5m/min to 6.0m/min. After the process is completed, oxygen (O ₂ ) and argon (Ar) to clean the chamber, break the vacuum and turn off the power, then open the chamber to take out the polyimide film to complete the surface plasma modification.

This invention refers to the SLP metallization process (SLP process) of Japan's Okuno Pharmaceutical Co., Ltd., and uses the SLP series of electroless nickel plating reagents to successively perform charge adjustment, pre-immersion, catalysis, acceleration, and reduction nickel plating steps. The operating conditions are described as follows.

Immerse the hydrophilized PI substrate in a 65°C SLP-200 solution for 75 seconds for charge adjustment, then remove and rinse with water.

Continuously immerse in 25°C SLP-300 solution for 25 seconds and SLP-400 solution for 75 seconds to allow the catalyst to adhere to the surface of the transparent substrate, then remove and rinse with water.

Then soak in 35℃ SLP-500 solution for 75 seconds to activate the catalyst, take out and rinse with water.

Finally, soak in 40℃ SLP-660 solution, control the pH value to 8.5±0.1, react for 250 seconds, take out and wash with water, and the nickel metal layer/polyimide film composite film is completed, and the thickness of the single-sided nickel layer is between 0.08~0.10μm. .

The copper layer of the present invention is not particularly limited, as long as it can form a copper layer for subsequent etching circuits. In addition, in one embodiment of the present invention, it is preferred to use electroplating to plate the copper layer on the nickel metal layer. The electroplating solution used for the copper layer can be a commercially available product, such as copper sulfate electroplating solution.

(Purchased from Jiwei Industrial Co., Ltd.), etc. The working conditions are as follows. The above-mentioned nickel metal layer/polyimide film composite film is first heat-treated at 120℃ for 24 hours, and then 2wt% sulfuric acid is used to remove the oxide layer on the surface of the nickel metal layer. Then, electrolytic plating is performed in the plating tank. The plating solution contains 150g/L sulfuric acid, 120g/L copper sulfate and 50ppm chlorine ions, as well as appropriate plating additives such as brighteners and flattening agents. The current density is 4 ASD, and the average plating speed is about 0.5μm/min. By controlling the power-on time, a copper metal layer with a thickness of 0.2~20μm can be deposited on the surface of the nickel layer according to demand.

Implementation example

<Testing method>

The thermal and electrical properties of the polyimide films obtained in the following examples were measured using the following methods.

(1) Young's film thickness: measured according to ASTM D882 standard specification using Hounsfield H10K-S tensile testing machine.

(2) Thermal expansion coefficient CTE: According to ASTM D696, the Q400 TMA instrument produced by TA Instruments was used to measure the thermal expansion coefficient of the transparent polyimide film at 50~200℃, and the heating rate was set to 10℃/min. In order to remove the stress caused by heat treatment, the residual stress was removed by the first measurement, and the second measurement result was used as the actual value.

(3) Adhesion force: measured according to IPC-TM-6502.4.9 standard using Hounsfield H10K-S tensile testing machine.

<Example 1>

Preparation of polyimide membrane

7.139 g of p-phenylenediamine (p-PDA, 0.066 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After all the DMAc was dissolved, 15.538 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.165 mole) was added. The mixture was stirred for 1 hour and the temperature was maintained at 25°C. Then 25.694 g of 2,2' -dimethyl-4,4'-diaminobenzidine (m-TB, 0.121 mole), stir until completely dissolved, then slowly add 11.999 grams of pyromellitic anhydride (PMDA, 0.055 mole), stir for 0.5 hours to dissolve and react, and the temperature of the solution is maintained at 25°C, then add 12.301 grams of BPDA and react for 1 hour, then add 6.609 grams of ODA (ODA, 0.033 mol), after it is completely dissolved, add 19.747 grams of BPDA (0.0671 mol), stir and react for 2 hours, use a small amount of BPDA to adjust the viscosity to 250,000±300,000 cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take out 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.12 grams of acetic anhydride dilution and 5.41 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Laminate production

A nickel metal layer is formed on the surface of a polyimide film by electroless plating, so that the nickel metal layer is in contact with the polyimide film; and after the nickel metal layer is formed, heat treatment is performed, and then a copper layer is formed thereon by electrolytic plating.

In the present invention, the nickel layer is formed by chemical plating on one or both sides of the polyimide substrate. As for the chemical plating, it can be a known chemical plating method and is not particularly limited. In addition, as for a specific example of chemical plating, the polyimide membrane can be first subjected to surface hydrophilization treatment, and the surface treatment known in the technical field can be adopted here, and it is not limited here.

In the present invention, the nickel layer is formed by chemical plating on one or both sides of the polyimide substrate. The present invention refers to the SLP metallization process (SLP process) of Japan Okuno Pharmaceutical Co., Ltd., and uses the SLP series of electroless nickel plating reagents to successively perform charge adjustment, pre-immersion, catalysis, acceleration, and reduction nickel plating steps. The operating conditions are described as follows.

Immerse the hydrophilized PI substrate in a 65°C SLP-200 solution for 75 seconds for charge adjustment, then remove and rinse with water.

Continuously immerse in 25°C SLP-300 solution for 25 seconds and SLP-400 solution for 75 seconds to allow the catalyst to adhere to the surface of the transparent substrate, then remove and rinse with water.

Then soak in 35℃ SLP-500 solution for 75 seconds to activate the catalyst, take out and rinse with water.

Finally, soak it in a 40℃ SLP-660 solution, control the pH value to 8.5±0.1, react for 250 seconds, take it out and wash it with water to complete the nickel metal layer/polyimide film composite film, and the thickness of the single-sided nickel layer is between 0.08~0.10μm.

The copper layer working conditions are as follows. The nickel metal layer/polyimide film composite film is first heat treated at 120℃ for 24 hours, and then 2wt% sulfuric acid is used to remove the oxide layer on the surface of the nickel metal layer. Then, electrolytic plating is performed in the plating tank. The plating solution contains 150g/L sulfuric acid, 120g/L copper sulfate and 50ppm chlorine ions, as well as appropriate plating additives such as brighteners and flattening agents. The current density is 4 ASD, and the average plating speed is about 0.5μm/min. By controlling the power-on time, a copper metal layer with a thickness of 0.2~20μm can be deposited on the surface of the nickel layer as required.

<Example 2>

Preparation of polyimide membrane

7.167 g of p-phenylenediamine (p-PDA, 0.0663 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 17.551 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.165 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 18.762 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.088 mole) was added. The mixture was stirred until it was completely dissolved. Then 12.047 g of pyromellitic anhydride (PMD A, 0.055 mole), stirred for 0.5 hours to dissolve and react, and the temperature of the solution was maintained at 25°C, then 7.150 grams of BPDA was added and reacted for 1 hour, and then 13.272 grams of 4,4'-diaminodiphenyl ether (ODA, 0.066 mol) was added, and after it was completely dissolved, 23.076 grams of BPDA (0.0784 mol) was added, and after stirring and reacting for 2 hours, a trace amount of BPDA was used to adjust the viscosity to 250,000±300,000 cps, and finally a copolymer polyamide solution with a solid content of 20% was obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.15 grams of acetic anhydride dilution and 5.43 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as Example 1

<Example 3>

Preparation of polyimide membrane

7.167 g of p-phenylenediamine (p-PDA, 0.0663 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 18.526 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0552 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 18.762 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0884 mole) was added. The mixture was stirred until it was completely dissolved. Then 12.047 g of pyromellitic acid was slowly added. Anhydride (PMDA, 0.0552 mole) and 8.45 g BPDA, stir for 1 hour, then add 13.272 g 4,4'-diaminodiphenyl ether (ODA, 0.0663 mole), slowly add 20.801 g BPDA (0.0707 mole) after all dissolved, stir for 12 hours to dissolve and react, and maintain the temperature of the solution at 25°C, then use a small amount of BPDA to adjust the viscosity to 250,000±300,000 cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. Stir for 10 minutes, then dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.15 grams of acetic anhydride dilution and 5.43 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 20 minutes, then heat it up to 170℃ at a rate of 1.8℃/min and bake it for 20 minutes, then heat it up to 350℃ at a rate of 2.0℃/min and bake it for 20 minutes as the final treatment.

<Example 4>

Preparation of polyimide membrane

7.228 g of p-phenylenediamine (p-PDA, 0.0668 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 18.683 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0635 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 18.921 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.209 mole) was added. The mixture was stirred until it was completely dissolved. Then 14.579 g of pyromellitic anhydride (PMD A, 0.0668 mole), stirred for 0.5 hours to dissolve and react, and the temperature of the solution was maintained at 25°C, then 5.244 grams of BPDA was added and reacted for 1 hour, and then 13.384 grams of 4,4'-diaminodiphenyl ether (ODA, 0.0668 mol) was added, and after it was completely dissolved, 20.977 grams of BPDA (0.0713 mol) was added, and after stirring and reacting for 2 hours, a trace amount of BPDA was used to adjust the viscosity to 250,000±300,000 cps, and finally a copolymer polyamide solution with a solid content of 20% was obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.21 grams of acetic anhydride dilution and 5.48 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as Example 1

<Example 5>

Preparation of polyimide film: Same as Example 4

Preparation of laminate: Surface plasma modification of polyimide film is performed. The polyimide film is fixed on the unwinding reel and connected to the film guide. The tension is set to 2kg, the working pressure is 300mTorr, the power is 10kW, the nitrogen flow rate is adjusted to 2000sccm, the length of the plasma zone is 11m, and the line speed is 5.0m/min. After the process is completed, oxygen ( _O2 ) and argon (Ar) are introduced in sequence to clean the chamber. After breaking the vacuum, the power is turned off, and then the chamber is opened to take out the polyimide film to complete the surface plasma modification. The subsequent steps are the same as those in Example 1.

<Example 6>

Preparation of polyimide membrane

7.290 g of p-phenylenediamine (p-PDA, 0.0674 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After all the DMAc was dissolved, 18.842 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.064 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. Then 19.082 g of 2,2'- Dimethyl-4,4'-diaminobenzidine (m-TB, 0.0899 mole), stir until completely dissolved, then slowly add 17.155 grams of pyromellitic anhydride (PMDA, 0.0786 mole), stir for 0.5 hours to dissolve and react, and the temperature of the solution is maintained at 25°C, then add 1.983 grams of BPDA and react for 0.5 hours, then add 13.499 grams of ODA (ODA, 0.0674 mol), wait for it to dissolve completely, then add 21.156 grams of BPDA (0.0719 mol), stir for 2 hours, and use a small amount of BPDA to adjust the viscosity to 250,000±300,000 cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.27 grams of acetic anhydride dilution and 5.52 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Example 7>

Preparation of polyimide film: Same as Example 6

Preparation of laminate: Surface plasma modification of polyimide film, fix the polyimide film on the unwinding reel and connect it to the film guide, set the tension to 2kg, the working pressure to 300mTorr, the power supply to 10kW, adjust the nitrogen flow to 2000sccm, the length of the plasma zone to 11m, and the line speed to 5.0m/min; after the process is completed, oxygen ( _O2 ) and argon (Ar) are introduced into the chamber to clean it, and the power supply is turned off after breaking the vacuum, and then the chamber is opened to take out the polyimide film, and the surface plasma modification is completed. The subsequent steps are the same as in Example 1. The subsequent steps are the same as in Example 1.

<Example 8>

Preparation of polyimide film: Same as Example 6

Preparation of laminate: Surface plasma modification of polyimide film is performed. The polyimide film is fixed on the unwinding reel and connected to the film guide. The tension is set to 2kg, the working pressure is 300mTorr, the power is 10kW, the argon (Ar) flow rate is adjusted to 2000sccm, the length of the plasma zone is 11m, and the line speed is 5.0m/min. After the process is completed, oxygen ( _O2 ) and argon (Ar) are introduced in sequence to clean the chamber. After breaking the vacuum, the power is turned off, and then the chamber is opened to take out the polyimide film to complete the surface plasma modification. The subsequent steps are the same as those in Example 1.

<Example 9>

Preparation of polyimide membrane

9.925 g of p-phenylenediamine (p-PDA, 0.0918 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 24.304 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0826 mole) was added. The mixture was stirred for 2 hours and the temperature was maintained at 25°C. Then 19.486 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0918 mole) was added and stirred until it was completely dissolved. Then 17.517 g of pyromellitic anhydride (PMDA, 0.0803 mole) was slowly added and stirred for 1 hour until it was dissolved and reacted. The temperature of the solution was maintained at 25°C. Then ODA was added. 9.189g (ODA, 0.0459mol), after it is completely dissolved, add 18.566g BPDA (0.0631mol), stir and react for 2 hours, then use a small amount of BPDA to adjust the viscosity to 250,000±300,000cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.42 grams of acetic anhydride dilution and 5.64 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 1>

Preparation of polyimide membrane

11.090 g of p-phenylenediamine (p-PDA, 0.1025 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 24.138 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.082 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 19.352 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0912 mole) was added. The mixture was stirred until it was completely dissolved. Then 12.427 g of 6.845 g of 4,4'-diaminodiphenyl ether (ODA, 0.0342 mol) was added, and after it was completely dissolved, 25.143 g of BPDA (0.0855 mol) was added. After stirring for 2 hours, a small amount of BPDA was used to adjust the viscosity to 250,000±300,000 cps. Finally, a copolymer polyamide solution with a solid content of 20% was obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.37 grams of acetic anhydride dilution and 5.6 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 2>

Preparation of polyimide membrane

7.167 g of p-phenylenediamine (p-PDA, 0.0663 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 11.565 g of 1,2,4,5-benzenetetracarboxylic anhydride (PMDA, 0.0530 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. Then 18.762 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0884 mole) was added. The mixture was stirred until it was completely dissolved. Then 0.482 g of pyromellitic anhydride (PMDA, 0.0786 mole) was slowly added. 20.151g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0685mole) was stirred for 0.5 hours to dissolve and react, and the temperature of the solution was maintained at 25°C. Then 13.272g of 4,4'-diaminodiphenyl ether (ODA, 0.00.0663mol) was added. After it was completely dissolved, 27.626g of BPDA (0.0939mol) was added. After stirring for 2 hours, a small amount of BPDA was used to adjust the viscosity to 250,000±300,000cps. Finally, a copolymer polyamide solution with a solid content of 20% was obtained.

Take out 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.15 grams of acetic anhydride dilution and 5.43 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 3>

Preparation of polyimide membrane

13.272 g of 4,4'-diaminodiphenyl ether (ODA, 0.0663 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 11.565 g of pyromellitic anhydride (PMDA, 0.0393 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 18.762 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0884 mole) was added. The mixture was stirred until it was completely dissolved. Then 0.482 g of pyromellitic anhydride (PMDA, 0.0022 mole) was slowly added. le), and 20.801 grams of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0707 mole) were stirred for 0.5 hours to dissolve and react, and the temperature of the solution was maintained at 25°C, and then 7.167 grams of p-phenylenediamine (PDA, 0.0663 mol) was added. After it was completely dissolved, 26.976 grams of BPDA (0.0917 mol) was added. After stirring for 2 hours, a small amount of BPDA was used to adjust the viscosity to 250,000±300,000cps, and finally a copolymer polyamide solution with a solid content of 20% was obtained.

Take out 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.15 grams of acetic anhydride dilution and 5.43 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas, apply the degassing solution to a glass plate, and then use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 4>

Preparation of polyimide membrane

13.272 g of 4,4'-diaminodiphenyl ether (ODA, 0.0663 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 15.601 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0530 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 18.762 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0884 mole) was added. The mixture was stirred until it was completely dissolved. Then 12.047 g of pyromellitic anhydride (PMDA, 0.0530 mole) was slowly added. 0552mole), and 4.550g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0155mole) were stirred for 0.5 hours to dissolve and react, and the temperature of the solution was maintained at 25°C, then 7.167g of p-phenylenediamine (PDA, 0.0552mol) was added, and after it was completely dissolved, 27.626g of BPDA (0.0939mol) was added, and after stirring for 2 hours, a small amount of BPDA was used to adjust the viscosity to 250,000±300,000cps, and finally a copolymer polyamide solution with a solid content of 20% was obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.15 grams of acetic anhydride dilution and 5.43 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 5>

Preparation of polyimide membrane

12.985 g of phenylenediamine (PDA, 0.120 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 31.797 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.1081 mole) was added. The mixture was stirred for 2 hours while the temperature was maintained at 25°C. 25.493 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0120 mole) was added and stirred until it was completely dissolved. , then slowly add 26.192 grams of pyromellitic anhydride (PMDA, 0.120 mole) and 2.473 grams of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0084 mole) and stir for 0.5 hours to dissolve and react, and the temperature of the solution is maintained at 25°C. After stirring for 2 hours, use a small amount of BPDA to adjust the viscosity to 250,000±300,000cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.77 grams of acetic anhydride dilution and 5.90 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 6>

Preparation of polyimide membrane

25.493 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.120 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 31.797 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.1081 mole) was added. The mixture was stirred for 2 hours while the temperature was maintained at 25°C. 12.985 g of p-phenylenediamine (PDA, 0.120 mole) was added and stirred until it was completely dissolved. , then slowly add 26.192 grams of pyromellitic anhydride (PMDA, 0.120 mole) and 2.473 grams of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0084 mole) and stir for 0.5 hours to dissolve and react, and the temperature of the solution is maintained at 25°C. After stirring for 2 hours, use a small amount of BPDA to adjust the viscosity to 250,000±300,000cps, and finally obtain a copolymer polyamide solution with a solid content of 20%.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.77 grams of acetic anhydride dilution and 5.90 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 7>

Preparation of polyimide membrane

22.954 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.108 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After all the DMAc was dissolved, 28.631 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.108 mole) was added. The mixture was stirred for 2 hours while the temperature was maintained at 25°C. 21.650 g of 4,4'-diaminodiphenyl ether (ODA, 0.0108 mole) was added and stirred until the mixture was completely dissolved. After the mixture is completely dissolved, 23.584 g of pyromellitic anhydride (PMDA, 0.108 mole) and 2.227 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0076 mole) are slowly added and stirred for 0.5 hours to allow them to dissolve and react. The temperature of the solution is maintained at 25°C. After stirring and reacting for 2 hours, a small amount of BPDA is used to adjust the viscosity to 250,000±300,000 cps. Finally, a copolymer polyamide solution with a solid content of 20% is obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 6.99 grams of acetic anhydride dilution and 5.32 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

<Comparison Example 8>

Preparation of polyimide membrane

22.954 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (PDA, 0.0449 mole) was added to 400 g of N,N-dimethylacetamide (DMAc). After it was completely dissolved, 11.901 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0404 mole) was added. The mixture was stirred for 1 hour while the temperature was maintained at 25°C. 19.082 g of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB, 0.0899 mole) and 2.430 g of p-phenylenediamine (0.0225 mole) were added. The mixture was stirred until it was completely dissolved. 17.155 g of DMAc was added slowly. 6.611 grams of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA, 0.0225 mole) were stirred for 1 hour and then 13.499 grams of 4,4'-diaminodiphenyl ether (ODA, 0.0674 mole) were added. After the ODA was completely dissolved, 23.470 grams of BPDA (0.0798 mole) were added. The mixture was stirred for 2 hours and the temperature of the solution was maintained at 25°C. Finally, a small amount of BPDA was used to adjust the viscosity to 250,000±300,000 cps. Finally, a copolymer polyamide solution with a solid content of 20% was obtained.

Take 33 grams of the above copolymer polyamide solution and add 17 grams of N,N-dimethylacetamide (DMAc) to dilute the solid content to 13.2%. After stirring for 10 minutes, dilute acetic anhydride and DMAc at a weight ratio of 5:1, and then dilute 3-methylpyridine and DMAc at a weight ratio of 1:1. Then add 7.27 grams of acetic anhydride dilution and 5.52 grams of 3-methylpyridine dilution. After uniform stirring, use a centrifugal degasser to degas. Apply the degassing solution to a glass plate and use a scraper with a gap of 600μm to apply it. Place the coated sample in an oven at 80℃ for 40 minutes, then heat it up to 170℃ at a rate of 3.6℃/min for 10 minutes, then heat it up to 260℃ at a rate of 5.9℃/min for 10 minutes, and finally heat it up to 350℃ at a rate of 8.13℃/min for 20 minutes as the final treatment.

Preparation of laminate: Same as in Example 1.

Implementation examples and comparison examples table

The contents of the above specific embodiments are for the purpose of describing the present invention in detail. However, such embodiments are for illustration only and are not intended to limit the present invention. Those skilled in the art can understand that various changes or modifications made to the present invention without departing from the scope defined by the scope of the attached patent application are part of the present invention.

Claims (6)

A polyimide film is formed by forming a copolymer of a dianhydride and a dian acid, wherein the dianhydride comprises 60-80 mol% of the total dianhydride mole of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 20-40 mol% of pyromellitic anhydride (PMDA); the diamine comprises 10-40 mol% of the total diamine mole of p-phenylenediamine (p-PDA), and 10-40 mol% of the total diamine mole of 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB). The total molar number of diamine is 30-60 mol% and 4,4'-diaminodiphenyl ether (ODA) accounts for 10-40 mol% of the total molar number of diamine; wherein the copolymerized polyimide has a copolymer chain segment composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA), and the copolymer chain segment accounts for 25-40% of the total molar number of the polyimide, so that the thermal expansion coefficient CTE of the polyimide film is less than 15ppm/℃, and the Young's modulus is greater than 7GPa. As described in the first item of the patent application, the molar ratio of the dianhydride to the diamine in the copolymer chain segment composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA) must be greater than 0.9. The polyimide film as described in item 1 of the patent application, wherein the polyimide film is made by chemical cyclization and the baking temperature is between 350°C and 380°C. A laminate comprising a polyimide film as described in item 1 of the patent application and a metal layer attached to the polyimide film, wherein the bonding force between the metal layer and the polyimide film is greater than 0.65 Kgf/cm, and the bonding force is still greater than 0.5 Kgf/cm after baking at 150°C for at least 24 hours. As described in item 4 of the patent application scope, the polyimide film can be surface treated using plasma so that the bonding force between the metal layer and the polyimide film is greater than 0.8Kgf/cm. The laminated plate as described in item 5 of the patent application scope, wherein the plasma surface treatment can be atmospheric plasma, wherein the gas used can be nitrogen, argon, oxygen, carbon tetrafluoride or a mixture of the above.