CN115584022A - A kind of polyimide film material containing cage type silsesquioxane and preparation method thereof - Google Patents

Abstract

The invention discloses a method for preparing a low dielectric constant polyimide film material containing cage silsesquioxane (Double-decker bifunctional group POSS). Composed of diamine monomers and dianhydride monomers, wherein the mass content of bisamino-terminated polysilsesquioxane is 2% to 10%, and the molar ratio of diamine monomers to dianhydride monomers is 1:1 to 1.05 . The polysilsesquioxane (POSS) polyimide film material provided by the invention has a lower dielectric constant and has the original excellent mechanical properties of the polyimide material. The chemical structural formula of the POSS is shown in the following structural formula:

The invention prepares a polyimide film material with low dielectric constant and high tensile strength through POSS diamine monomer, which is suitable for 5G electronic packaging materials.

Description

A kind of polyimide film material containing cage type silsesquioxane and preparation method thereof

technical field

The invention relates to the technical field of polyimide film materials, in particular to a polyimide film material containing cage-type silsesquioxane (POSS) and a preparation method thereof.

Background technique

As a high-performance polymer material, polyimide (PI) has attracted much attention in academia and industry due to its good performance in electronics, microelectronics, optoelectronics and other fields. However, the performance of traditional aromatic polyimides is not enough to meet the various new requirements for materials put forward by the rapid development of electronic and microelectronic technology. In order to further improve the mechanical and electrical properties of polyimide, polyhedral oligomeric cage silsesquioxane (POSS) has attracted the attention of many researchers. Introducing POSS into the polyimide substrate can not only improve the thermal and dielectric properties of the material, but also obtain better flame retardant and anti-atomic oxygen capabilities. However, POSS-containing polyimides have not been widely used due to the limitation of preparation cost and cumbersome monomer synthesis process.

Cage silsesquioxane (POSS) is a nanoscale cage structure composed of Si and O elements, which has good heat resistance; its hollow structure can reduce the Dielectric constant of nanocomposites; peripheral organic groups enhance compatibility with polymer matrix. In recent years, POSS has become a research hotspot in the field of organic-inorganic nanocomposite dielectric materials. POSS also has various configurations, such as octavinyl cage silsesquioxane (T8-POSS), octaamino cage silsesquioxane (OAPS), double splint oligomeric silsesquioxane (DDSQ) Wait.

CN113667158A discloses a kind of low-dielectric polyimide-based composite film and its preparation method and application, it is doped nano POSS particle as filler in the polyimide-based film preparation process, reduces the obtained polyimide-based film Dielectric constant, but POSS cannot be dispersed in nanometer size in the matrix, and the performance improvement is limited.

POSS with single-reaction functional group, its active reactive group can react with groups on various polymer chains to obtain a wide variety of graft copolymers with different properties. CN104610341A discloses single-reaction functional group POSS as molecular chain end-capping agent Preparation of siloxane-terminated polymer materials.

The POSS of multi-reaction functional group can be used as the cross-linking agent of thermosetting polymer material, also can rely on its good compatibility with polymer base material and polymer blend to prepare composite material, CN111286076A discloses to use aminopropyl-POSS As a crosslinking agent and modified polyimide airgel, the airgel has high adsorption performance, hydrophobic performance and certain flexibility in the fields of waste gas and wastewater treatment, heat preservation and heat insulation, and catalyst adsorption .

CN 113248709 discloses a polyimide prepared from diamine monomers and dianhydride monomers; the diamine monomers include POSS diamines and diamines containing pyridine structures, wherein the POSS is a T8 configuration , the polyimide has both low shrinkage and high strength, and it is tested that the dielectric constant of the polyimide is between 2.13-2.59 under the condition of 1kHz.

The dielectric properties of polyimide films are usually evaluated by the dielectric constant and dielectric loss. At present, the research on low dielectric constant polyimide films in the prior art is basically concentrated on the condition of kHz. For the 5G scene GHz The development of polyimide films with low dielectric constant and low dielectric loss under certain conditions is an unknown field, and the current low dielectric polyimide films cannot be well applied.

Based on the above-mentioned technical problems, the present invention adopts the in-situ polymerization method to introduce POSS into PI through chemical bonding to prepare a polyimide film with low dielectric constant and low dielectric loss, which can be used for 5G electronic packaging materials and shielding material.

Contents of the invention

Based on the problems existing in the background technology, the present invention unexpectedly finds that the polyimide film modified by cage silsesquioxane (POSS) of DDSQ configuration has a low dielectric constant at a frequency of 10 GHz, and more unexpectedly also It was found to have low dielectric loss at a frequency of 10 GHz. The above thin film material has high dimensional stability while maintaining good mechanical properties and good visible light transmittance.

The present invention provides a kind of polyimide containing cage type silsesquioxane (DDSQ type POSS) and preparation method thereof, and the repeating unit of described polyimide comprises following structure:

Wherein: Ar is the same or different, selected from the following groups:

R ₁ are the same or different, selected from the following groups:

R ₂ are the same or different, selected from the following groups:

The present invention further provides the preparation method of above-mentioned polyimide precursor solution, described method comprises the steps:

The diamine monomer is fully dissolved in the aprotic polar solvent, and then the aprotic polar solution in which the dianhydride monomer is dissolved is added to react to obtain a polyimide precursor solution.

Described diamine monomer comprises the POSS diamine shown in following formula:

R ₁ are the same or different, selected from the following groups:

R ₂ are the same or different, selected from the following groups:

The structure of the dianhydride monomer is:

Wherein: Ar is the same or different, selected from the following groups:

Preferably, the reaction is carried out under the protection of nitrogen or inert gas at -10-35°C for 0.5-6h, more preferably at 0-5°C or 5-30°C for 1-2h,

Preferably, the molar ratio of the dianhydride monomer and the diamine monomer is 1:0.85 to 1.15, and in the polyimide precursor reaction solution, the total mass percentage of the dianhydride monomer and the diamine monomer The concentration is 10-35wt%.

Preferably, the aprotic polar solvent is composed of N-methylpyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, diethylene glycol One or more of the monomethyl ethers are mixed in any proportion.

Preferably, the viscosity of the polyimide precursor solution is 1000-10000 cp, more preferably 2000-5000 cp.

More preferably, the diamine monomer also includes 1,4-diaminobenzene, 4,4'-diaminobiphenyl, 4,4-diaminodiphenyl ether, 4,4'-diamino Benzophenone, 4,4'-diaminodiphenyl ether diphenyl sulfone, 4,4'-diaminodiphenyl ether bisphenol A, 2,2'-dimethyl-4,4'-diaminobiphenyl One or more diamine monomers mixed in any proportion.

Preferably, the molar percentage of the POSS diamine in the total amount of diamines is 1% to 10%;

The present invention further provides a kind of preparation method of polyimide film, described method comprises the steps:

Coating film: coating the aforementioned polyimide precursor solution on the substrate;

High-temperature imidization: In a nitrogen atmosphere, dry the coated substrate, and then heat it up to 360°C in gradients, and keep each gradient for 5-90 minutes.

Stress relief: naturally cool down to room temperature to prepare the polyimide film.

Preferably, the substrate is selected from copper, aluminum and glass.

Preferably, the coating process is selected from spin coating method, spray coating method, dipping method and casting method.

Preferably, the drying condition is 50-80°C for 8-24 hours, more preferably 60°C for 12 hours.

Preferably, the gradient heating conditions are: heating to 100°C, holding for 30-90 minutes; reheating to 160°C, holding for 30-90 minutes; reheating to 220°C, holding for 30-90 minutes; reheating to 280°C, holding for 30 minutes ~90min; then heat to 320°C, keep warm for 30-90min; finally, heat to 340-360°C, keep warm for 5-60min. More preferably, the holding time at 160°C, 220°C, 280°C, and 320°C is preferably 60 minutes; the final heating temperature is preferably 350°C, and the reaction time is preferably 10-30 minutes.

Preferably, in the stress relieving step, the cooling rate is preferably 2-5 °C/min, and the high-temperature section at the beginning of cooling is 350-150 °C under nitrogen protection.

Through above-mentioned technical scheme, the POSS polyimide film that preparation method of the present invention makes obtains the following beneficial effects:

1. Compared with the polyimide in the prior art, the polyimide film provided by the present invention still has a low dielectric constant at a frequency of 10 GHz and has excellent mechanical properties.

2. The polyimide film provided by the present invention has low dielectric loss at a frequency of 10 GHz.

3. The present invention directly modifies the POSS structure on the main chain of the polyimide molecule through chemical bonds, which overcomes the problems of uneven dispersion of POSS in the material and limited improvement of material performance.

Description of drawings

Fig. 1 is the broadband dielectric and impedance spectrograms of Examples 1-4.

detailed description

A cage-type imide film material with a low dielectric constant cage-type silsesquioxane (POSS) structure, characterized in that the preparation route is as follows:

In a three-neck flask equipped with mechanical stirring, a constant temperature and low temperature bath, a thermometer and a constant pressure dropping funnel, add the prescribed amount of diamine monomer, and use an inert gas for protection. Stir at room temperature, dissolve with a small amount of solvent, and control the temperature to the reaction temperature after the diamine monomer is completely dissolved. Dissolve the dianhydride monomer in part of the solvent, and add dropwise to the reaction system at a controlled rate. After the dropwise addition, stop the reaction when the viscosity reaches the maximum. After degassing, a polyamic acid solution film with a certain thickness is obtained by scraping, and after complete imidization, a polyimide film is obtained, dried, and annealed to the final product.

Example 1:

Before the reaction starts, the diamine monomer is vacuum-dried at 40-50°C for 12 hours, and the dianhydride monomer is vacuum-dried at 100-110°C for 24 hours. In a nitrogen atmosphere: 0.033g POSS diamine (DDSQ), 0.1311 Add g 4,4'-diaminodiphenyl ether (ODA) into a 100ml three-necked flask equipped with mechanical stirring, constant temperature and low temperature bath, thermometer and constant pressure dropping funnel, and stir at room temperature. Add 12ml of anhydrous dimethylacetamide (DMAC) to dissolve, after the complete dissolution, control the temperature to 10°C, add 1.0699g of 2,3,3',4'-biphenyltetracarboxylic dianhydride (s-BPDA), 1.0699g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (a-BPDA) was dissolved in 8ml of anhydrous DMAC, and was added dropwise to the reaction system at a rate of 1ml/min. After completion, add 0.0061g of diphenylmethane diisocyanate (MDI), and after the rod climbing phenomenon occurs, continue the reaction for 2h to end the reaction. After degassing, use a coating machine to scrape-coat a polyimide acid solution film with uniform thickness, dry most of the DMAC solvent at a low temperature of 60°C to obtain a polyamic acid gel film, and dry it at 100°C, 160°C, and 220°C. ℃, 280℃, 320℃, 350℃ are different gradients for programmed temperature rise. Cool to room temperature, peel the polyimide film from the substrate, heat up to 80°C for annealing, and obtain a polyimide film with a smooth surface and uniform thickness.

Example 2:

Before the reaction starts, the diamine monomer is vacuum-dried at 40-50°C for 12 hours, and the dianhydride monomer is vacuum-dried at 100-110°C for 24 hours. In a nitrogen atmosphere: 0.08g POSS diamine (DDSQ), 0.1311 Add g ODA into a 100ml three-necked flask equipped with mechanical stirring, constant temperature and low temperature bath, thermometer and constant pressure dropping funnel, and stir at room temperature. Add 12ml of anhydrous DMAC to dissolve, after complete dissolution, control the temperature to 10°C, dissolve 1.0699g of s-BPDA and 1.0699g of a-BPDA in 8ml of anhydrous DMAC, drop by drop at a rate of 1ml/min into the reaction system. After the dropwise addition was completed, 0.0061 g of MDI was added, and after the rod-climbing phenomenon appeared, the reaction was continued for 2 h to end the reaction. After degassing, use a coater to scrape coat a polyimide acid solution film with uniform thickness, and dry most of the DMAC solvent at a low temperature of 60°C to obtain a polyamic acid gel film. Programmable temperature rise with different gradients of 100°C, 160°C, 220°C, 280°C, 320°C, and 350°C, cool to room temperature, peel the polyimide film from the substrate, heat up to 80°C for annealing, and obtain a surface Flat, uniform thickness polyimide film.

Example 3:

Before the reaction starts, the diamine monomer is vacuum-dried at 40-50°C for 12 hours, and the dianhydride monomer is vacuum-dried at 100-110°C for 24 hours. In a nitrogen atmosphere: 0.1265g POSS diamine (DDSQ), 0.1311 Add g ODA into a 100ml three-necked flask equipped with mechanical stirring, constant temperature and low temperature bath, thermometer and constant pressure dropping funnel, and stir at room temperature. Add 12ml of anhydrous DMAC to dissolve, after complete dissolution, control the temperature to 10°C, dissolve 1.0699g of s-BPDA and 1.0699g of a-BPDA in 8ml of anhydrous DMAC, drop by drop at a rate of 1ml/min into the reaction system. After the dropwise addition was completed, 0.0061 g of MDI was added, and after the rod-climbing phenomenon appeared, the reaction was continued for 2 h to end the reaction. After degassing, use a coater to scrape coat a polyimide acid solution film with uniform thickness, and dry most of the DMAC solvent at a low temperature of 60°C to obtain a polyamic acid gel film. Programmable temperature rise with different gradients of 100°C, 160°C, 220°C, 280°C, 320°C, and 350°C, cool to room temperature, peel the polyimide film from the substrate, heat up to 80°C for annealing, and obtain a surface Flat, uniform thickness polyimide film.

Example 4:

Add 0.3165g POSS diamine (DDSQ) and 0.1311g ODA strictly dewatered into a 100ml three-necked flask equipped with mechanical stirring, constant temperature and low temperature bath, thermometer and constant pressure dropping funnel, and stir at room temperature. Add 12ml of anhydrous DMAC to dissolve. After complete dissolution, control the temperature to 10°C, dissolve 1.0699gs-BPDA and 1.0699g of a-BPDA in 8ml of anhydrous DMAC, and add dropwise at a rate of 1ml/min to in the reaction system. After the dropwise addition, 0.0061g of MDI was added, and after the rod climbing phenomenon appeared, the reaction was continued for 2h to end the reaction. Add a mixed solution of triethylamine/acetic anhydride = 1:1, stop adding when a large amount of powdery solid appears, filter, wash the precipitate with methanol, and dry to obtain a light yellow powder solid. Use N,N-dimethylformamide (DMF) to dissolve the solid, continuously stir and dilute to obtain a polyimide solution with a viscosity of about 5000 cp at 25°C. A polyimide acid solution film with uniform thickness was obtained by scraping with a coating machine, and most of the DMF solvent was dried at a low temperature of 60° C. to obtain a polyimide gel film. Raise the temperature to 150°C for 2 hours, cool to room temperature, peel the polyimide film from the substrate, and heat up to 80°C for annealing to obtain a polyimide film with a smooth surface and uniform thickness.

Example 5:

Add dried 3.165g POSS diamine (DDSQ) and 1.311g ODA into a 3000ml small reactor with mechanical stirring, and stir at room temperature. Add 240ml of anhydrous DMAC to dissolve, and after it is completely dissolved, control the temperature to 10°C. 21.398g of s-BPDA and 21.398g of a-BPDA were dissolved in 160ml of anhydrous DMAC, and added dropwise to the reaction system at a rate of 1ml/min. After the dropwise addition, 0.122g of MDI was added, and after the rod climbing phenomenon appeared, the reaction was continued for 2h to end the reaction. Stand still for a period of time to degas, use a coater to scrape coat a polyimide acid solution film with uniform thickness, and dry most of the DMAC solvent at a low temperature of 60°C to obtain a polyamic acid gel film. Programmable temperature rise with different gradients of 100°C, 160°C, 220°C, 280°C, 320°C, and 350°C, cool to room temperature, peel the polyimide film from the substrate, heat up to 80°C for annealing, and obtain a surface Flat, uniform thickness polyimide film.

Comparative example 1 (embodiment 6):

The specific embodiment is consistent with Example 1, except that the POSS monomer is octaaminocage silsesquioxane (OAPS).

Comparative example 2 (embodiment 7):

The specific embodiment is consistent with Example 2, except that the POSS monomer is octaaminocage silsesquioxane (OAPS).

Comparative example 3 (embodiment 8):

The specific embodiment is consistent with Example 3, except that the POSS monomer is octavinyl cage silsesquioxane (T8-POSS).

Comparative example 4 (embodiment 9):

The specific embodiment is consistent with Example 4, except that POSS diamine (DDSQ) is replaced by ODA in equimolar amounts.

Example 10

Test the dielectric constant and dielectric loss of the polyimide film of Examples 1-9 at 25°C and 10GHz. The instrument used is N5224B PNA microwave network analyzer, and the measurement results are shown in the table below

Dielectric constant Dielectric loss Example 1 3.161 0.00301 Example 2 3.090 0.00296 Example 3 2.981 0.00279 Example 4 2.826 0.00262 Example 5 2.721 0.00216 Comparative example 1 3.227 0.00541 Comparative example 2 3.428 0.00838 Comparative example 3 3.336 0.00750 Comparative example 4 3.633 0.00859

Table 1

From the above test results, it can be known that the polyimide film modified by DDSQ configuration POSS has a lower dielectric value than ordinary polyimide film and polyimide film modified by other configuration POSS under the condition of 10 GHz. permittivity and dielectric loss.

Claims (10)

1. a polyimide containing cage type silsesquioxane, said polyimide comprises the following repeating unit structure:

Wherein: Ar is the same or different, selected from the following groups:

R ₁ are the same or different, selected from the following groups:

R ₂ are the same or different, selected from the following groups:

CH3. 2. the preparation method of the precursor solution of polyimide as claimed in claim 1, described method comprises the steps: Fully dissolving the diamine monomer in an aprotic polar solvent, then adding the aprotic polar solution in which the dianhydride monomer is dissolved, and reacting to obtain the polyimide precursor solution; Described diamine monomer comprises the POSS diamine monomer shown in following formula:

Wherein, R ₁ is the same or different, and is selected from the following groups:

R ₂ are the same or different, selected from the following groups:

CH3 The structure of the dianhydride monomer is:

Wherein: Ar is the same or different, selected from the following groups:

3. The method according to claim 2, characterized in that, the reaction is carried out under the protection of nitrogen or inert gas at -10-35°C for 0.5-6h. 4. The method according to claim 2, wherein the molar ratio of the dianhydride monomer to the diamine monomer is 1:0.85 to 1.15, and in the polyimide precursor reaction solution, the The total mass percent concentration of the dianhydride monomer and the diamine monomer is 10-35 wt%. 5. The method according to claim 2, wherein the aprotic polar solvent is composed of N-methylpyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacetamide One or more of amide, dimethyl sulfoxide and diethylene glycol monomethyl ether are mixed in any proportion. 6. The method according to claim 2, wherein the diamine monomer also comprises 1,4-diaminobenzene, 4,4'-diaminobiphenyl, 4,4-diamino Diphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl ether diphenylsulfone, 4,4'-diaminodiphenyl ether bisphenol A, 2,2'-dimethyl One or more diamine monomers of 4,4'-diaminobiphenyl mixed in any proportion. 7. The method according to any one of claims 2 or 6, characterized in that the molar percentage of the POSS diamine in the total amount of diamines is 2% to 10%. 8. A preparation method for polyimide film, said method comprising the steps of: Coating film: coating the polyimide precursor solution described in any one of claims 1-7 on the substrate; High-temperature imidization: In a nitrogen atmosphere, dry the coated substrate, and then heat it up to 360°C in gradients, and keep each gradient for 5-90 minutes. Stress relief: naturally cool down to room temperature to prepare the polyimide film. 9. The method according to claim 8, characterized in that, the gradient heating conditions are: heating to 100°C, heat preservation for 30-90min; reheating to 160°C, heat preservation for 30-90min; reheating to 220°C, heat preservation 30-90min; reheat to 280°C, keep warm for 30-90min; reheat to 320°C, keep hold for 30-90min; finally, heat to 340-360°C, keep hold for 5-60min. 10. The method according to claim 8, characterized in that, in the stress relieving step, the cooling rate is preferably 2-5 °C/min, and the high-temperature section at the beginning of cooling is 350-150 °C under nitrogen protection.

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