Polyimide-modified thermotropic liquid crystal resin composition and double-sided copper-clad plate

Abstract

The present application relates to the technical field of high-performance resin film, and particularly relates to a polyimide modified thermotropic liquid crystal resin composition and double-sided copper clad plate. The composition comprises a polyimide resin and a thermotropic liquid crystal resin, wherein the polyimide resin comprises a structure shown in formula (1) and each group in formula (1) has a specific selection. The present application significantly improves the cohesion and orientation of the resin from the chemical structure and condensed state structure by using a thermoplastic polyimide resin with a specific structure to blend and modify the thermotropic liquid crystal resin. The double-sided copper clad plate prepared therefrom has high peeling strength and excellent isotropy, and has a good application prospect in the field of high-frequency flexible microwave circuit and the like. Formula (1).

Description

Technical Field

[0001] This invention relates to the field of high-performance resin film technology, specifically to a polyimide-modified thermotropic liquid crystal resin composition and a double-sided copper-clad laminate. Background Technology

[0002] Since the invention of thermotropic liquid crystal polymers (LCPs) in the 1980s, especially after Celanese Corps launched Vectra A950, a type II thermotropic liquid crystal polymer (LCP) resin, in 1985, its unique mechanical, electrical, and heat-resistant properties have attracted great attention in the field of engineering plastics and have been quickly brought to market.

[0003] With the rapid development of communication technology, electronic signal transmission frequencies are advancing towards the GHz level, making the dielectric loss caused by interlayer dielectric materials increasingly significant. Thermotropic liquid crystal polymer films (LCPs) are ideal dielectric materials for high-frequency communication flexible printed circuit boards (FPCs) due to their extremely low water absorption (0.04%) and extremely low dielectric loss at high frequencies (0.002@10GHz). However, traditional polymer film manufacturing methods cannot meet the melt processing requirements of thermotropic liquid crystal polymer resins, making it difficult to fabricate high-performance LCP polymer films from LCP resins (such as Vectra A950).

[0004] Since the late 1980s, several companies have conducted research on the technology of melt extrusion of LCP resin to manufacture LCP films, achieving breakthroughs in the following years. Existing technologies such as US4161470, US4837268, US005091138A, US005326848A, CN100351068C, CN101223835B, and CN104220236A report various thermotropic liquid crystal polymer resins and films, as well as their preparation methods. These polymers are generally composed of large molecules with significant geometric asymmetry and rod-like molecular chains. This results in weak cohesion within the molecular chains and easy delamination within the polymer film, leading to low peel strength in double-sided copper-clad laminates prepared from these polymer films, which fails to meet application requirements. Furthermore, under external forces, the molecular chains are prone to orientation, causing significant differences in the longitudinal (MD) and transverse (TD) mechanical properties and dimensional stability of the prepared liquid crystal polymer films, severely impacting their application and performance in high-frequency communication fields. Therefore, how to improve the cohesion and orientation of thermotropic liquid crystal polymer films to better meet their application requirements in the field of high-frequency communication has become an urgent problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a polyimide-modified thermotropic liquid crystal resin composition and a double-sided copper-clad laminate. This polyimide-modified thermotropic liquid crystal resin composition has good film-forming properties, high cohesive strength, and excellent isotropy. The double-sided copper-clad laminate made from it has high peel strength and excellent dimensional stability. To achieve the above objectives, the present invention provides a polyimide-modified thermotropic liquid crystal resin composition comprising a polyimide resin and a thermotropic liquid crystal resin, wherein the polyimide resin comprises the structure shown in formula (1): Equation (1) ; Ar1 is selected from phenylene, and One or more of them, R1 is selected from chemical bonds, , One or more of the following, wherein each R2 and each R3 are independently selected from one or more of H, C1-C3 perfluoroalkyl and C6-C10 aryl, and R4 is selected from phenylene and / or biphenylene; Ar2 is selected from , and One or more of them, R5 and R6 are each independently selected from chemical bonds, , , , , , , and One or more of the following, R7, R8, and R9 are each independently selected from one or more of phenylene, biphenylene, and C1-C6 alkylene groups, R 10 and R 11 Each is independently selected from chemical bonds and / or phenylene; n is an integer selected from 5 to 50.

[0006] A second aspect of the present invention provides a method for preparing a polyimide-modified thermotropic liquid crystal resin composition, the method comprising: mixing a polyimide resin and a thermotropic liquid crystal resin and granulating them to obtain a polyimide-modified thermotropic liquid crystal resin composition, wherein the polyimide resin and the thermotropic liquid crystal resin are as defined in the first aspect above.

[0007] A third aspect of the present invention provides a polyimide-modified thermotropic liquid crystal resin film prepared from the above-described polyimide-modified thermotropic liquid crystal resin composition or the polyimide-modified thermotropic liquid crystal resin composition prepared by the above method.

[0008] A fourth aspect of the present invention provides a method for preparing the above-mentioned polyimide-modified thermotropic liquid crystal resin film, the method comprising: subjecting the polyimide-modified thermotropic liquid crystal resin composition to blown film treatment and heat treatment to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0009] The fifth aspect of the present invention provides a double-sided copper-clad laminate made from the above-mentioned polyimide-modified thermotropic liquid crystal resin film.

[0010] This invention utilizes a thermoplastic polyimide resin with a specific structure to blend and modify a thermotropic liquid crystal resin. This significantly improves the resin's cohesiveness and orientation from both chemical and condensed-state perspectives. It not only increases the entanglement between the thermotropic liquid crystal resin molecular chains, thereby enhancing intermolecular cohesion, but also disrupts the orientation structure of the molecular chains, significantly improving the performance differences between the MD and TD directions of the thin film. The resulting double-sided copper-clad laminate exhibits high peel strength and excellent isotropy, showing promising application prospects in fields such as high-frequency flexible microwave circuits.

[0011] The technical solution of the present invention has the following advantages: (1) The melt viscosity of the polyimide-modified thermotropic liquid crystal resin composition is stable and controllable, which is conducive to high-quality film blowing molding; (2) The molecular chains of the polyimide-modified thermotropic liquid crystal resin composition have low liquid crystal orientation characteristics; (3) Polyimide-modified thermotropic liquid crystal resin film has excellent isotropy; (4) The double-sided copper-clad laminate prepared by polyimide modified thermotropic liquid crystal resin film has high peel strength and excellent dimensional stability. Attached Figure Description

[0012] Figure 1 Peel strength curves of double-sided copper-clad laminates in Example 1 and Comparative Example 1; Figure 2 The figures show the field test results of the peel strength of the double-sided copper-clad laminates in Example 1 and Comparative Example 1. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] In this invention, , , , In structures with dashed connecting keys, the dashed lines indicate the connection points and represent connecting keys.

[0015] In one aspect, the present invention provides a polyimide-modified thermotropic liquid crystal resin composition, the composition comprising a polyimide resin and a thermotropic liquid crystal resin, wherein the polyimide resin comprises the structure shown in formula (1): Equation (1) ; Ar1 is selected from phenylene, and One or more of them, R1 is selected from chemical bonds, , One or more of the following, wherein each R2 and each R3 are independently selected from one or more of H, C1-C3 perfluoroalkyl and C6-C10 aryl, and R4 is selected from phenylene and / or biphenylene; Ar2 is selected from , and One or more of them, R5 and R6 are each independently selected from chemical bonds, , , , , , , and One or more of the following, R7, R8, and R9 are each independently selected from one or more of phenylene, biphenylene, and C1-C6 alkylene groups, R 10 and R 11 Each is independently selected from chemical bonds and / or phenylene; n is an integer selected from 5 to 50.

[0016] According to the present invention, the thermoplastic polyimide resin containing the structure shown in formula (1) has excellent high-temperature resistance and melting characteristics. It is an amorphous aggregated structure and exhibits a random distribution. Blending it with thermotropic liquid crystal resin can modify the thermotropic liquid crystal resin from the perspectives of chemical structure and condensed state structure, thereby significantly improving the cohesiveness and orientation of the resin and avoiding the problems of easy delamination after film formation and large differences in properties in the MD and TD directions. This allows the double-sided copper-clad laminate prepared from it to have high peel strength and excellent dimensional stability. In order to better modify the thermotropic liquid crystal resin and improve the resin performance, the structure of the polyimide resin can be further selected. Preferably, Ar1 is selected from... , , , , , , , , , , and One or more of them, preferably , , , , , , , and One or more of them.

[0017] Preferably, Ar2 is selected from , , , , , , , , , , , , and One or more of them, preferably , , , , , , , , , , and One or more of them.

[0018] Preferably, n is selected from an integer between 20 and 35, for example, it can be a value such as 20, 25, 30 and 35 and any range between these values.

[0019] According to the present invention, polyimide resins with specific structures and molecular weights can achieve better modification effects. Preferably, the weight-average molecular weight of the polyimide resin is 1500-30000 g / mol, more preferably 10000-25000 g / mol, and more preferably 15000-22000 g / mol. For example, it can be 15000 g / mol, 18000 g / mol, 20000 g / mol, and 22000 g / mol, or any value between these values.

[0020] According to the present invention, the thermotropic liquid crystal resin can be any type of thermotropic liquid crystal resin conventional in the art. However, in order to achieve better modification effect of the polyimide resin and obtain a modified resin with superior performance, the thermotropic liquid crystal resin can be further selected. Preferably, the thermotropic liquid crystal resin is selected from p-hydroxybenzoic acid / 6-hydroxy-2-naphthyl acid copolymer, p-hydroxybenzoic acid / ethylene terephthalate copolymer, and p-hydroxybenzoic acid / terephthalic acid / 4,4' One or more of biphenyl copolymers, preferably one or more of p-hydroxybenzoic acid / 6-hydroxy-2-naphthyl acid copolymers.

[0021] Preferably, the melting point of the thermotropic liquid crystal resin is 240-360℃, more preferably 270-330℃, for example, it can be 270℃, 285℃, 305℃, 318℃, and 330℃, or any range between these values. The thermotropic liquid crystal resin can be prepared by methods disclosed in the prior art or obtained commercially.

[0022] According to the present invention, in order to obtain an ideal polyimide-modified thermotropic liquid crystal resin composition, it is necessary to adjust the amount of polyimide resin and thermotropic liquid crystal resin. Preferably, the amount of thermotropic liquid crystal resin is 2-20 parts by weight relative to 1 part by weight of the polyimide resin, preferably 4-16 parts by weight, for example, 5 parts by weight, 8 parts by weight, 12 parts by weight and 16 parts by weight, and any value between these values.

[0023] A second aspect of the present invention provides a method for preparing a polyimide-modified thermotropic liquid crystal resin composition, the method comprising: mixing a polyimide resin and a thermotropic liquid crystal resin and granulating them to obtain a polyimide-modified thermotropic liquid crystal resin composition, wherein the polyimide resin and the thermotropic liquid crystal resin are as defined in the first aspect above.

[0024] According to the present invention, in order to obtain a polyimide-modified thermotropic liquid crystal resin composition with better performance properties, the granulation method is preferably twin-screw melt extrusion granulation.

[0025] Preferably, the temperature of the twin-screw melt extrusion is 250-360℃, more preferably 270-330℃, for example, it can be 270℃, 285℃, 300℃ and 330℃ and any range between these values.

[0026] According to the present invention, the preparation method of the polyimide resin can be selected within a wide range. In order to obtain a polyimide resin with better properties, preferably, the preparation method of the polyimide resin includes: in the presence of an organic solvent, performing a polymerization reaction on an aromatic diamine monomer and an aromatic dianhydride monomer and adding phthalic anhydride for end-capping reaction to obtain the polyimide resin.

[0027] According to the present invention, in order to obtain an ideal polyimide resin, preferably, the mass ratio of the aromatic diamine monomer, the aromatic dianhydride monomer and the phthalic anhydride is 1:0.5-1.5:0.01-0.5, more preferably 1:0.8-1.2:0.05-0.3, for example, it can be 1:1.06:0.08, 1:0.94:0.12, 1:1:0.2 and 1:1.2:0.3 and other values ​​and any range between these values.

[0028] According to the present invention, in order to enable the materials to be more fully dispersed and in contact, and to provide a good reaction environment, preferably, the organic solvent is selected from one or more of chloroform, 1,4-dioxane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, γ-butyrolactone, ethyl lactate, cyclopentanone, cyclohexanone, methyl ethyl ketone, ethyl acetate, and butyl acetate, more preferably one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, and ethyl acetate.

[0029] Preferably, the mass ratio of the aromatic diamine monomer to the organic solvent is 1:2-10, more preferably 1:4-8, for example, it can be 1:4, 1:6, 1:7 and 1:8 and any range between these values.

[0030] According to the present invention, in order to facilitate the polymerization reaction, preferably, the conditions for the polymerization reaction include: a temperature of 0-40°C and a time of 3-8 hours. More preferably, the conditions for the polymerization reaction include: a temperature of 10-30°C (e.g., values ​​such as 10°C, 20°C, 25°C, and 30°C, or any range thereof), and a time of 4-6 hours (e.g., values ​​such as 4 hours, 4.5 hours, 5 hours, and 6 hours, or any range thereof).

[0031] According to the present invention, phthalic anhydride is added after the polymerization reaction to carry out a capping reaction. To obtain better reaction results, preferably, the capping reaction conditions include: a temperature of 0-40°C and a time of 6-20 hours. More preferably, the capping reaction conditions include: a temperature of 10-30°C (e.g., values ​​such as 10°C, 20°C, 25°C, and 30°C, or any range thereof), and a time of 8-16 hours (e.g., values ​​such as 8 hours, 12 hours, 14 hours, and 16 hours, or any range thereof).

[0032] According to the present invention, after the end-capping reaction is completed, the obtained reaction solution can be post-treated. In order to obtain polyimide resin with good properties and higher purity, the post-treatment can be carried out in the following manner: adding a dehydrating agent (usually a suitable solvent such as toluene, xylene and acetic anhydride is used as the dehydrating agent, and the amount is usually 0.5-1.5 times the mass of the aromatic diamine monomer) to the reaction solution and dehydrating (usually at high temperature of 160-190°C), then removing the dehydrating agent (usually at high temperature of 200-250°C), precipitating the obtained resin solution in a poor solvent (for example, a suitable solvent such as water, methanol, ethanol and acetone can be used as the poor solvent, and the amount is only enough to make all the resin product precipitate), and obtaining the polyimide resin by filtration, drying and pulverization.

[0033] According to the present invention, in order to obtain the desired polyimide resin, preferably, the aromatic diamine monomer is selected from one or more of 1,4-p-phenylenediamine, 1,3-m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4'-bis(4'-aminophenoxy)benzene, 1,3-bis(4'-aminophenoxy)benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 4,4-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 2,6-bis(4-amino-2-trifluoromethylphenoxy)benzene, 2-phenyl-4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, and 1,5-bis(4-amino-2-trifluoromethylphenoxy)benzene.

[0034] Preferably, the aromatic dianhydride monomer is selected from pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether carboxylic dianhydride, 2,3',3,4'-diphenyl ether carboxylic dianhydride, 3,3',4 One or more of the following: 4'-diphenyl ether tetracarboxylic dianhydride, bisphenol A type diether dianhydride, (4-phthalic anhydride)formyloxy-4-phthalate, bis[(3,4-dianhydride)phenyl]terephthalate, p-phenylene bisphenyltriester dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 4,4'-terephthalodioxybisphthalic anhydride, and 4,4'-(hexafluoroisopropyl)diphthalic anhydride.

[0035] According to a preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, the aromatic diamine monomer is selected from 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 3,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, 1,3-bis(4'-aminophenoxy)benzene, 2-phenyl-4,4'-diaminodiphenyl ether, 1,5-bis(4-amino-2-trifluoromethylphenoxy)benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, and 2,6-bis(4-amino-2-trifluoromethylphenoxy)benzene. One or more of (4-amino-2-trifluoromethylphenoxy)benzene; the aromatic dianhydride monomer is selected from one or more of 2,3',3,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether carboxylic dianhydride, 2,3',3,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropyl)diphenyl anhydride, p-phenylene bisphenyltriterpenoid dianhydride, bis[(3,4-dianhydride)phenyl]terephthalate, and 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride.

[0036] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine and 3,4'-diaminodiphenyl ether are used as aromatic diamine monomers in a weight ratio of 3-6:1, and 2,3',3,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-diphenyl ethercarboxylic dianhydride are used as aromatic dianhydride monomers in a weight ratio of 6-12:1.

[0037] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether and 1,3-bis(4'-aminophenoxy)benzene in a weight ratio of 3-6:1 are used as aromatic diamine monomers, and 2,3',3,4'-benzophenone tetracarboxylic dianhydride and 3,3',4,4'-biphenyl tetracarboxylic dianhydride in a weight ratio of 1-2:1 are used as aromatic dianhydride monomers.

[0038] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 2-phenyl-4,4'-diaminodiphenyl ether is used as an aromatic diamine monomer, and 2,3',3,4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-biphenyl tetracarboxylic dianhydride and 4,4'-(hexafluoroisopropyl)diphthalic anhydride are used as aromatic dianhydride monomers in a weight ratio of 3-6:3-6:1.

[0039] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 1,5-bis(4-amino-2-trifluoromethylphenoxy)benzene and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene in a weight ratio of 1-2:1 are used as aromatic diamine monomers, and p-phenylene bisphenyltriterpenoid dianhydride and bis[(3,4-dianhydride)phenyl]terephthalate in a weight ratio of 1-2:1 are used as aromatic dianhydride monomers.

[0040] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 2,6-bis(4-amino-2-trifluoromethylphenoxy)benzene and 3,4'-diaminodiphenyl ether are used as aromatic diamine monomers in a weight ratio of 3-6:1, and 2,3',3,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-diphenyl ether carboxylic dianhydride are used as aromatic dianhydride monomers in a weight ratio of 6-12:1.

[0041] According to a particularly preferred embodiment of the present invention, in the preparation process of the above-mentioned polyimide resin, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine and 3,4'-diaminodiphenyl ether are used as aromatic diamine monomers in a weight ratio of 3-6:1, and 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride and 3,3',4,4'-diphenyl ether carboxylic dianhydride are used as aromatic dianhydride monomers in a weight ratio of 6-12:1.

[0042] A third aspect of the present invention provides a polyimide-modified thermotropic liquid crystal resin film prepared from the above-described polyimide-modified thermotropic liquid crystal resin composition or the polyimide-modified thermotropic liquid crystal resin composition prepared by the above method.

[0043] A fourth aspect of the present invention provides a method for preparing the above-mentioned polyimide-modified thermotropic liquid crystal resin film, the method comprising: subjecting the polyimide-modified thermotropic liquid crystal resin composition to blown film treatment and heat treatment to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0044] According to the present invention, in order to better form a film and obtain a polyimide-modified thermotropic liquid crystal resin film with superior properties, preferably, the conditions for the blown film treatment include: a melt temperature of 280-360°C and a ring blowing temperature of 20-60°C. More preferably, the conditions for the blown film treatment include: a melt temperature of 290-330°C (for example, values ​​such as 290°C, 300°C, 320°C, and 330°C, and any range thereof), and a ring blowing temperature of 30-40°C (for example, values ​​such as 30°C, 35°C, and 40°C, and any range thereof).

[0045] Preferably, the heat treatment conditions include: a temperature of 180-330℃ and a time of 2-24h. More preferably, the heat treatment conditions include: a temperature of 200-310℃ (e.g., values ​​such as 200℃, 250℃, 280℃, and 310℃, or any range thereof), and a time of 8-16h (e.g., values ​​such as 8h, 12h, 14h, and 16h, or any range thereof).

[0046] The fifth aspect of the present invention provides a double-sided copper-clad laminate made from the above-mentioned polyimide-modified thermotropic liquid crystal resin film.

[0047] The double-sided copper-clad laminate can be manufactured using conventional flexible double-sided copper-clad laminate pressing processes. For example, it can be manufactured by hot-pressing one side of the polyimide-modified thermotropic liquid crystal resin film with a copper foil, and then hot-pressing the other side of the polyimide-modified thermotropic liquid crystal resin film with a copper foil to obtain the double-sided copper-clad laminate. The hot-pressing conditions are typically: a temperature of 250-350℃ (e.g., values ​​such as 250℃, 280℃, 300℃, 320℃, and 350℃, or any range thereof), and a pressure of 0.5-2 kg / cm². 2 (For example, it can be 0.5 kg / cm) 2 0.8kg / cm 2 0.9kg / cm 2 1kg / cm 2 and 2kg / cm 2 (equal values ​​and the range between any of these values). The hot pressing treatment is preferably carried out in a non-reactive gas atmosphere, such as nitrogen and / or argon.

[0048] This invention utilizes a thermoplastic polyimide resin with a specific structure to blend and modify a thermotropic liquid crystal resin. This significantly improves the resin's cohesiveness and orientation from both chemical and condensed-state perspectives. It not only increases the entanglement between the thermotropic liquid crystal resin molecular chains, thereby enhancing intermolecular cohesion, but also disrupts the orientation structure of the molecular chains, significantly improving the performance differences between the MD and TD directions of the film. The resulting double-sided copper-clad laminate exhibits no film separation, and the film demonstrates excellent adhesion strength to the copper foil, with a peel strength exceeding 0.9 N / mm. This shows promising application prospects in fields such as high-frequency communications.

[0049] The present invention will be described in detail below through embodiments.

[0050] In the following examples, all apparatuses used are conventional in the art, all operations performed are conventional in the art, and all raw materials and reagents used are commercially available. Specifically, the thermotropic liquid crystal resins of Celanese Vectra A950 (Celanese Corporation, USA, melting point 280℃), Duwei LCP358 (Shanghai Duwei Chemical Technology Co., Ltd., melting point 310℃), and Kingfa R8000 (Kingfa Science & Technology Co., Ltd., melting point 280℃) are all p-hydroxybenzoic acid / 6-hydroxy-2-naphthyl acid copolymers. The thermotropic liquid crystal resin of Unigeco Rodrun LC5000 (Unigico Corporation, Japan, melting point 247℃) is a p-hydroxybenzoic acid / ethylene terephthalate copolymer.

[0051] Example 1 (1) Preparation of polyimide resin 40 parts by weight of 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine and 10 parts by weight of 3,4'-diaminodiphenyl ether were dissolved in 350 parts by weight of N-methylpyrrolidone. 48 parts by weight of 2,3',3,4'-biphenyltetracarboxylic dianhydride and 5 parts by weight of 3,3',4,4'-diphenyl ethercarboxylic dianhydride were added, and the mixture was reacted at 25°C for 5 hours. Then, 4 parts by weight of phthalic anhydride were added, and the reaction was continued at 25°C for 12 hours. 45 parts by weight of toluene were added to the reaction solution, and water was removed at 160°C. Toluene was then distilled off at 200°C. The resulting resin solution was precipitated in water, filtered, dried, and pulverized to obtain a polyimide resin with an average degree of polymerization of 20 (weight-average molecular weight approximately 15000 g / mol).

[0052] (2) Preparation of polyimide-modified thermotropic liquid crystal resin composition Ten parts by weight of polyimide resin were mixed with 90 parts by weight of thermotropic liquid crystal resin (Celanis Vectra A950), and the mixture was melt-extruded and granulated at 270°C using a twin-screw extruder to obtain a polyimide-modified thermotropic liquid crystal resin composition.

[0053] (3) Preparation of polyimide-modified thermotropic liquid crystal resin film The polyimide-modified thermotropic liquid crystal resin composition was melt-blown at 300°C using a blown film machine with a ring blowing temperature of 35°C. The resulting film was then heat-treated at 200°C for 12 hours to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0054] (4) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of a polyimide-modified thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 300℃, pressure 0.8 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 300℃, pressure 0.8 kg / cm²).2 This yields a double-sided copper-clad laminate.

[0055] Example 2 (1) Preparation of polyimide resin 40 parts by weight of 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether and 10 parts by weight of 1,3-bis(4'-aminophenoxy)benzene were dissolved in 300 parts by weight of N-methylpyrrolidone. 25 parts by weight of 2,3',3,4'-benzophenone tetracarboxylic dianhydride and 22 parts by weight of 3,3',4,4'-biphenyl tetracarboxylic dianhydride were added, and the mixture was reacted at 25°C for 5 hours. Then, 6 parts by weight of phthalic anhydride were added, and the reaction was carried out at 30°C for 8 hours. 45 parts by weight of toluene were added to the reaction solution, and water was removed at 190°C. Toluene was then distilled off at 220°C. The resulting resin solution was precipitated in ethanol, filtered, dried, and pulverized to obtain a polyimide resin with an average degree of polymerization of 25 (weight-average molecular weight approximately 18000 g / mol).

[0056] (2) Preparation of polyimide-modified thermotropic liquid crystal resin composition Six parts by weight of polyimide resin and 94 parts by weight of thermotropic liquid crystal resin (both LCP358) were mixed and melt-extruded and granulated at 300°C using a twin-screw extruder to obtain a polyimide-modified thermotropic liquid crystal resin composition.

[0057] (3) Preparation of polyimide-modified thermotropic liquid crystal resin film The polyimide-modified thermotropic liquid crystal resin composition was melt-blown at 320°C using a blown film machine with a ring blowing temperature of 40°C. The resulting film was then heat-treated at 260°C for 10 hours to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0058] (4) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of a polyimide-modified thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 320℃, pressure 1 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 320℃, pressure 1kg / cm²). 2 This yields a double-sided copper-clad laminate.

[0059] Example 3 (1) Preparation of polyimide resin 50 parts by weight of 2-phenyl-4,4'-diaminodiphenyl ether were dissolved in 200 parts by weight of N-methylpyrrolidone. Then, 20 parts by weight of 2,3',3,4'-benzophenone tetracarboxylic dianhydride, 25 parts by weight of 2,3',3,4'-biphenyltetracarboxylic dianhydride, and 5 parts by weight of 4,4'-(hexafluoroisopropyl)diphthalic anhydride were added. After dissolution, the mixture was reacted at 25°C for 6 hours. Then, 10 parts by weight of phthalic anhydride were added, and the reaction was carried out at 20°C for 14 hours. 40 parts by weight of toluene were added to the reaction solution, and water was removed at 180°C. The toluene was then distilled off at 200°C. The resulting resin solution was precipitated in water, filtered, dried, and pulverized to obtain a polyimide resin with an average degree of polymerization of 35 (weight-average molecular weight approximately 20,000 g / mol).

[0060] (2) Preparation of polyimide-modified thermotropic liquid crystal resin composition 15 parts by weight of polyimide resin and 85 parts by weight of thermotropic liquid crystal resin (Kingfa R8000) were mixed and melt-extruded and granulated at 330°C using a twin-screw extruder to obtain a polyimide-modified thermotropic liquid crystal resin composition.

[0061] (3) Preparation of polyimide-modified thermotropic liquid crystal resin film The polyimide-modified thermotropic liquid crystal resin composition was melt-blown at 320°C using a blown film machine with a ring blowing temperature of 35°C. The resulting film was then heat-treated at 310°C for 12 hours to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0062] (4) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of a polyimide-modified thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 310℃, pressure 0.9 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 310℃, pressure 0.9 kg / cm²). 2 This yields a double-sided copper-clad laminate.

[0063] Example 4 (1) Preparation of polyimide resin 30 parts by weight of 1,5-bis(4-amino-2-trifluoromethylphenoxy)benzene and 20 parts by weight of 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene were dissolved in 400 parts by weight of N-methylpyrrolidone. 25 parts by weight of p-phenylene bisphenyltriterpenoid dianhydride and 15 parts by weight of bis[(3,4-dianhydride)phenyl]terephthalate were added, and the mixture was reacted at 20°C for 6 hours. Then, 5 parts by weight of phthalic anhydride were added, and the reaction was carried out at 25°C for 10 hours. 50 parts by weight of toluene were added to the reaction solution, and water was removed at 170°C. The toluene was then distilled off at 230°C. The resulting resin solution was precipitated in water, filtered, dried, and pulverized to obtain a polyimide resin with an average degree of polymerization of 25 (weight-average molecular weight approximately 20,000 g / mol).

[0064] (2) Preparation of polyimide-modified thermotropic liquid crystal resin composition 20 parts by weight of polyimide resin and 80 parts by weight of thermotropic liquid crystal resin (Celanis Vectra A950) were mixed and melt-extruded and granulated at 290°C using a twin-screw extruder to obtain a polyimide-modified thermotropic liquid crystal resin composition.

[0065] (3) Preparation of polyimide-modified thermotropic liquid crystal resin film The polyimide-modified thermotropic liquid crystal resin composition was melt-blown at 300°C using a blown film machine with a ring blowing temperature of 40°C. The resulting film was then heat-treated at 250°C for 12 hours to obtain a polyimide-modified thermotropic liquid crystal resin film.

[0066] (4) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of a polyimide-modified thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 310℃, pressure 0.8 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 310℃, pressure 0.8kg / cm). 2 This yields a double-sided copper-clad laminate.

[0067] Example 5 The method of Example 1 differs in that, in step (1), 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine is replaced with 2,6-bis(4-amino-2-trifluoromethylphenoxy)benzene.

[0068] Example 6 The method according to Example 1 differs in that, in step (1), 2,3',3,4'-biphenyltetracarboxylic dianhydride is replaced with 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride.

[0069] Example 7 The method of Example 1 differs in that, in step (2), the amount of thermotropic liquid crystal resin used is 20 parts by weight.

[0070] Example 8 The method of Example 1 differs in that, in step (2), the amount of thermotropic liquid crystal resin used is 200 parts by weight.

[0071] Example 9 The method of Example 1 differs in that, in step (2), the thermotropic liquid crystal resin (Cellanis Vectra A950) is replaced with thermotropic liquid crystal resin (Unigico Rodrun LC5000).

[0072] Comparative Example 1 (1) Preparation of thermotropic liquid crystal resin films The thermotropic liquid crystal resin (Celanis Vectra A950) was melt-blown at 300°C using a blown film machine, with a ring blowing temperature of 35°C. The resulting film was then heat-treated at 200°C for 12 hours to obtain a thermotropic liquid crystal resin film.

[0073] (2) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of the thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 300℃, pressure 0.8 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 300℃, pressure 0.8 kg / cm²). 2 This yields a double-sided copper-clad laminate.

[0074] Comparative Example 2 (1) Preparation of thermotropic liquid crystal resin films Thermotropic liquid crystal resin (all LCP358) was melt-blown at 320℃ using a blown film machine with a ring blowing temperature of 40℃. The resulting film was then heat-treated at 260℃ for 10 hours to obtain a thermotropic liquid crystal resin film.

[0075] (2) Preparation of double-sided copper clad laminate Under a nitrogen atmosphere, one surface of the thermotropic liquid crystal resin film was hot-pressed to a copper foil (temperature 320℃, pressure 1 kg / cm²). 2 Then, the other side surface is hot-pressed with copper foil (temperature 320℃, pressure 1kg / cm²). 2 This yields a double-sided copper-clad laminate.

[0076] Comparative Example 3 According to the method of Example 1, except that step (1) is not performed, and the polyimide resin in step (2) is replaced with structural polyimide resin KH-304 (degree of polymerization of 2, weight-average molecular weight of 1500 g / mol, produced by the Institute of Chemistry, Chinese Academy of Sciences).

[0077] Test Example 1 The polyimide resins of Examples 1-9 and Comparative Example 3 were subjected to performance tests.

[0078] Minimum melt viscosity: The melt viscosity of the resin material was tested using a TA Instruments AR2000 rheometer, and the minimum value was recorded. A parallel plate fixture with a plate diameter of 25 mm was used for testing. First, the resin material was pressed into circular discs with a diameter of 25 mm and a thickness of 1.3-1.5 mm to prepare the test sample. The test temperature was controlled by the rheometer's ETC (forced air furnace). The rheometer was preheated to the intermediate test temperature and zeroed, then cooled to the initial test temperature, and the sample was loaded. After the temperature stabilized, the test was conducted in flow mode, using the constant shear stress mode (104 Pa). The temperature range was 270-400℃, and the heating rate was 4℃ / min.

[0079] Particle size D90: Measured according to the method provided in GB / T 19077 "Particle size analysis by laser diffraction".

[0080] Glass transition temperature: The glass transition temperature was determined by the method provided in GB / T 19466.2 "Differential scanning calorimetry (DSC) for plastics - Part 2: Determination of glass transition temperature".

[0081] The test results are shown in Table 1.

[0082] Table 1

[0083] As shown in Table 1, the polyimide resin obtained using the technical solution of this invention has a suitable particle size and its minimum melt viscosity is within a good range, indicating that it has good processing performance. Meanwhile, its high glass transition temperature indicates excellent heat resistance. In contrast, the polyimide resin KH-304 used in Comparative Example 3 has a low melt viscosity and is unsuitable for film formation.

[0084] Test Example 2 The polyimide-modified thermotropic liquid crystal resin compositions or thermotropic liquid crystal resins of Examples 1-9 and Comparative Examples 1-3 were subjected to performance tests.

[0085] Minimum melt viscosity: Refer to Test Example 1.

[0086] Melt strength: Tested at the lowest melt viscosity temperature point according to the melt viscosity test curve, referring to the method provided in GB / T1040.3 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets".

[0087] Melting point: The melting point was determined by the method provided in GB / T 19466.3-2004 "Differential scanning calorimetry (DSC) for plastics - Part 3: Determination of melting and crystallization temperature and enthalpy".

[0088] The test results are shown in Table 2.

[0089] Table 2

[0090] As shown in Table 2, the polyimide-modified thermotropic liquid crystal resin composition obtained using the technical solution of this invention has a high melting point, indicating good heat resistance. Simultaneously, its minimum melt viscosity is within a good range, indicating good processability. Furthermore, it exhibits high melt strength, indicating deeper inter-chain entanglement and stronger cohesion. In contrast, Comparative Example 3, which uses a polyimide resin not required by this invention to modify the thermotropic liquid crystal resin, shows poor results. The melt strengths of Comparative Examples 1-2, which did not use polyimide resin to modify the thermotropic liquid crystal resin, are also in a low range.

[0091] Test Example 3 The resin films of Examples 1-9 and Comparative Examples 1-3 were subjected to performance tests.

[0092] Tensile strength and elongation at break: Tested according to the methods provided in GB / T 1040.3 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets".

[0093] Dielectric loss: Tested according to the method provided in IPC-TM-650 2.5.5.5 (Stripline Test for Permittivity and Loss Tangent (Dielectric Constant and Dissipation Factor) at X-Band).

[0094] Coefficient of thermal expansion: Tested according to the method provided in IPC-TM-650 2.4.41.3 (In-Plane Coefficient of Thermal Expansion, Organic Films).

[0095] The test results are shown in Table 3.

[0096] Table 3

[0097] As shown in Table 3, the polyimide-modified thermotropic liquid crystal resin film obtained using the technical solution of this invention exhibits small performance differences in the longitudinal (MD) and transverse (TD) directions, indicating its excellent isotropy. In contrast, Comparative Examples 1-2, which did not employ the technical solution of this invention, show significant performance differences in the MD and TD directions, while Comparative Example 3 did not form a film.

[0098] Test Example 4 The performance of the double-sided copper-clad laminates of Examples 1-9 and Comparative Examples 1-3 was tested.

[0099] Peel strength: Tested according to the method provided in IPC-TM-650 2.4.9 (Peel Strength, Flexible Dielectric Materials). The peel strength curves for Example 1 and Comparative Example 1 are shown below. Figure 1 As shown, the on-site test situation is as follows: Figure 2 As shown.

[0100] Dimensional stability: Tested according to the method provided in IPC-TM-650 2.2.4 (Dimensional Stability, Flexible Dielectric Materials).

[0101] The test results are shown in Table 4.

[0102] Table 4

[0103] As shown in Table 4, the double-sided copper-clad laminate obtained using the technical solution of this invention has higher peel strength and better isotropy, with lower offsets in both the MD and TD directions, exhibiting excellent dimensional stability. In contrast, Comparative Examples 1-2 show lower peel strength, poorer isotropy, and unsatisfactory dimensional stability, while Comparative Example 3 shows no film formation.

[0104] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polyimide-modified thermotropic liquid crystal resin composition, characterized in that, The composition comprises a polyimide resin and a thermotropic liquid crystal resin, wherein the polyimide resin comprises the structure shown in formula (1): Equation (1) ; Ar1 is selected from phenylene, and One or more of them, R1 is selected from chemical bonds, , One or more of the following, wherein each R2 and each R3 are independently selected from one or more of H, C1-C3 perfluoroalkyl and C6-C10 aryl, and R4 is selected from phenylene and / or biphenylene; Ar2 is selected from , and One or more of them, R5 and R6 are each independently selected from chemical bonds, , , , , , , and One or more of the following, R7, R8, and R9 are each independently selected from one or more of phenylene, biphenylene, and C1-C6 alkylene groups, R 10 and R 11 Each is independently selected from chemical bonds and / or phenylene; n is an integer selected from 5 to 50.

2. The composition according to claim 1, wherein, Ar1 is selected from , , , , , , , , , , and One or more of them, preferably , , , , , , , and One or more of the following; And / or, Ar2 is selected from , , , , , , , , , , , , and One or more of them, preferably , , , , , , , , , , and One or more of the following; And / or, n is an integer selected from 20 to 35.

3. The composition according to claim 1 or 2, wherein, The polyimide resin has a weight-average molecular weight of 1500-30000 g / mol, preferably 10000-25000 g / mol, and more preferably 15000-22000 g / mol; And / or, the thermotropic liquid crystal resin is selected from p-hydroxybenzoic acid / 6-hydroxy-2-naphthyl acid copolymer, p-hydroxybenzoic acid / ethylene terephthalate copolymer, and p-hydroxybenzoic acid / terephthalic acid / 4,4' One or more of biphenyl copolymers, preferably one or more of p-hydroxybenzoic acid / 6-hydroxy-2-naphthyl acid copolymers; And / or, the melting point of the thermotropic liquid crystal resin is 240-360°C, preferably 270-330°C; And / or, relative to 1 part by weight of the polyimide resin, the amount of the thermotropic liquid crystal resin is 2-20 parts by weight, preferably 4-16 parts by weight.

4. A method for preparing a polyimide-modified thermotropic liquid crystal resin composition, characterized in that, The method includes: mixing and granulating a polyimide resin and a thermotropic liquid crystal resin to obtain a polyimide-modified thermotropic liquid crystal resin composition, wherein the polyimide resin and the thermotropic liquid crystal resin are as defined in any one of claims 1-3.

5. The method according to claim 4, wherein, The granulation method is twin-screw melt extrusion granulation; Preferably, the temperature of the twin-screw melt extrusion is 250-360℃, and more preferably 270-330℃.

6. The method according to claim 4 or 5, wherein, The method for preparing the polyimide resin includes: in the presence of an organic solvent, polymerizing an aromatic diamine monomer and an aromatic dianhydride monomer and adding phthalic anhydride for end-capping reaction to obtain the polyimide resin; Preferably, the mass ratio of the aromatic diamine monomer, the aromatic dianhydride monomer, and the phthalic anhydride is 1:0.5-1.5:0.01-0.5, and more preferably 1:0.8-1.2:0.05-0.3; Preferably, the organic solvent is selected from one or more of chloroform, 1,4-dioxane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, γ-butyrolactone, ethyl lactate, cyclopentanone, cyclohexanone, methyl ethyl ketone, ethyl acetate, and butyl acetate; more preferably, it is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, and ethyl acetate. Preferably, the mass ratio of the aromatic diamine monomer to the organic solvent is 1:2-10, more preferably 1:4-8; Preferably, the polymerization reaction conditions include: a temperature of 0-40°C and a time of 3-8 hours; more preferably, the polymerization reaction conditions include: a temperature of 10-30°C and a time of 4-6 hours. Preferably, the conditions for the end-capping reaction include: a temperature of 0-40°C and a time of 6-20 hours; more preferably, the conditions for the end-capping reaction include: a temperature of 10-30°C and a time of 8-16 hours. Preferably, the aromatic diamine monomer is selected from one or more of 1,4-p-phenylenediamine, 1,3-m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4'-bis(4'-aminophenoxy)benzene, 1,3-bis(4'-aminophenoxy)benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 4,4-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 2,6-bis(4-amino-2-trifluoromethylphenoxy)benzene, 2-phenyl-4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, and 1,5-bis(4-amino-2-trifluoromethylphenoxy)benzene; Preferably, the aromatic dianhydride monomer is selected from pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether carboxylic dianhydride, 2,3',3,4'-diphenyl ether carboxylic dianhydride, 3,3',4 One or more of the following: 4'-diphenyl ether tetracarboxylic dianhydride, bisphenol A type diether dianhydride, (4-phthalic anhydride)formyloxy-4-phthalate, bis[(3,4-dianhydride)phenyl]terephthalate, p-phenylene bisphenyltriester dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 4,4'-terephthalodioxybisphthalic anhydride, and 4,4'-(hexafluoroisopropyl)diphthalic anhydride.

7. A polyimide-modified thermotropic liquid crystal resin film prepared from the polyimide-modified thermotropic liquid crystal resin composition according to any one of claims 1-3 or the polyimide-modified thermotropic liquid crystal resin composition prepared by the method according to any one of claims 4-6.

8. The method for preparing the polyimide-modified thermotropic liquid crystal resin film according to claim 7, characterized in that, The method includes subjecting a polyimide-modified thermotropic liquid crystal resin composition to blown film treatment and heat treatment to obtain a polyimide-modified thermotropic liquid crystal resin film.

9. The method according to claim 8, wherein, The conditions for the blown film treatment include: a melt temperature of 280-360℃ and a ring blowing temperature of 20-60℃; more preferably, the conditions for the blown film treatment include: a melt temperature of 290-330℃ and a ring blowing temperature of 30-40℃. And / or, the conditions for the heat treatment include: a temperature of 180-330°C and a time of 2-24 hours; more preferably, the conditions for the heat treatment include: a temperature of 200-310°C and a time of 8-16 hours.

10. A double-sided copper-clad laminate made from the polyimide-modified thermotropic liquid crystal resin film of claim 7.

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