Liquid crystal polymer, preparation process thereof, liquid crystal polymer composite material and application

Abstract

The invention discloses a liquid crystal polymer, which is derived from the following repetitive units by molar content: 55-65 mol% of-O-Ar1-CO-unit; 2 to 8 mol% of an-O-Ar2-CO-unit; 12 to 20 mol% of a-CO-Ar < 3-> CO <-> unit; 5 to 15 mol% of an-O-Ar4-O-unit; 2 to 8 mol% of a-Y-Ar5-Z-unit; the non-Newtonian index of the liquid crystal polymer is less than 0.75, and the non-Newtonian index can be less than 0.85 after filling, so that the liquid crystal polymer composite material has good ductility and thin-wall workpiece formability, and is suitable for an imaging module with the thickness of less than 0.1 mm.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a liquid crystal polymer, its preparation process, a liquid crystal polymer composite material, and its applications. Background Technology

[0002] Among the many key components of modern electronic devices, camera modules occupy a crucial position, with applications spanning smartphones, security monitoring, industrial inspection, and medical fields. The ever-increasing demands across industries for image quality, functional versatility, environmental adaptability, and accuracy pose increasingly stringent challenges to camera module design. Taking security monitoring as an example, the industry requires camera modules to accurately capture and clearly present high-quality image information. This necessitates complex designs involving compact camera module integration, multi-lens deployment, and numerous moving parts. In this context, the corresponding components are required to achieve an ultra-thin form with a thickness of less than 0.1mm. However, such ultra-thin components are highly susceptible to breakage and other abnormalities during multi-component assembly. This places extremely high demands on material performance, particularly the material's excellent ductility, to ensure that while meeting the ultra-thin design requirements, it can withstand the stresses during assembly without cracking, thereby guaranteeing the overall performance and reliability of the camera module.

[0003] Liquid crystal polymers (LCPs), with their unique regularly oriented molecular chain structure, possess excellent properties such as high flowability, high heat resistance, low dielectric constant, superior mechanical properties, self-flame retardant characteristics, and good chemical corrosion resistance, making them suitable for applications in camera modules. However, the industry commonly uses the addition of fillers (especially fiber fillers) to enhance the strength of LCP compositions. This not only reduces the moldability of thin-walled parts but also severely decreases ductility, failing to meet the material requirements of more complex and dense security surveillance camera modules. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid crystal polymer and a liquid crystal polymer composite material having good ductility and good formability of thin-walled parts.

[0005] This invention is achieved through the following technical solution:

[0006] A liquid crystal polymer having a non-Newtonian index of less than 0.75, and derived, in molar content, from the following repeating units:

[0007] -O-Ar1-CO- unit 55-65 mol%;

[0008] -O-Ar2-CO-unit 2-8mol%;

[0009] -CO-Ar3-CO- unit 12-20 mol%;

[0010] -O-Ar4-O-unit 5-15mol%;

[0011] -Y-Ar5-Z-unit 2-8mol%;

[0012] The -O-Ar1-CO- unit is derived from 4-hydroxybenzoic acid;

[0013] The -O-Ar2-CO- unit is derived from 2-hydroxy-6-naphthoic acid;

[0014] The -CO-Ar3-CO- unit is derived from at least one of terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid;

[0015] The -O-Ar4-O- unit is derived from at least one of 4,4'-dihydroxybiphenyl, hydroquinone, and 2,6-naphthol;

[0016] When a naphthyl unit is present in the -CO-Ar3-CO- unit and / or the -O-Ar4-O- unit, the -Y-Ar5-Z- unit is derived from at least one of 4-acetaminophen, p-aminophenol, and 6-acetamino-2-naphthol.

[0017] When the molar content of naphthyl units in the liquid crystal polymer is ≥4 mol%, and there are no naphthyl units in either the -CO-Ar3-CO- unit or the -O-Ar4-O- unit, the -Y-Ar5-Z- unit is derived from at least one of p-aminophenol, 4'-amino-4-biphenol, and 6-acetamido-2-naphthol.

[0018] The non-Newtonian index of the liquid crystal polymer can be 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, 0.53, 0.52, 0.51, 0.50, 0.49, 0.48, 0.47, 0.46, 0.45, The range of values ​​for any one or both of the following: 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, and 0.15.

[0019] Preferably, the non-Newtonian index of the liquid crystal polymer is in the range of 0.16-0.72.

[0020] LCPs have rigid or semi-rigid rod-like molecular chains and spontaneously form ordered liquid crystal phases (such as nematic or smectic phases) in the molten state. When LCPs are subjected to shear forces, their microstructure undergoes significant changes, resulting in a direct fluid thinning effect. The non-Newtonian index reflects the molecular weight distribution and flowability of the material, further demonstrating differences in molding, and also affects the orientation of microscopic molecules during molding, further influencing the material's ductility.

[0021] The molar content of the -CO-Ar3-CO- unit is 1: (the molar content of the -O-Ar4-O- unit + the molar content of the -Y-Ar5-Z- unit) = 1: (0.95-1.05).

[0022] In the liquid crystal polymer of the present invention, the molar content of -O-Ar1-CO- units can be any one or any two of the following: 55 mol%, 56 mol%, 57 mol%, 58 mol%, 59 mol%, 60 mol%, 61 mol%, 62 mol%, 63 mol%, 64 mol%, 65 mol%. The molar content of -O-Ar2-CO- units can be any one or any two of the following: 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%. The molar content of -CO-Ar3-CO- units can be any one or any two of the following: 12 mol%, 13 mol%, 14 mol%, 15 mol%, 16 mol%, 17 mol%, 18 mol%, 19 mol%, 20 mol%. The molar content of -O-Ar4-O- units can be 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, 11 mol%, 12 mol%, 13 mol%. The molar content of the -Y-Ar5-Z- unit can be any one or both of the following values: mol%, 14 mol%, 15 mol%, and the molar content of the -Y-Ar5-Z- unit can be any one or both of the following values: 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%.

[0023] Preferably, the non-Newtonian index of the liquid crystal polymer is less than 0.60;

[0024] More preferably, the non-Newtonian index of the liquid crystal polymer is less than 0.40.

[0025] More preferably, the -CO-Ar3-CO- unit is derived from terephthalic acid, the -O-Ar4-O- unit is derived from 2,6-naphthol, and the -Y-Ar5-Z- unit is derived from p-aminophenol.

[0026] Non-Newtonian exponents: obtained through the power-law model of Newton's laws; tested using a Dynisco LCR7000 capillary rheometer at a temperature 20°C above the melting point and a shear rate of 500–5000 s⁻¹. -1 Data were obtained by preheating a die with an inner diameter of 1 mm and a length of 40 mm for 4 minutes.

[0027] The Newtonian form of the power-law model is η a =Kγ n-1 , where η a γ is the apparent shear viscosity (in Pa·s), and γ is the shear rate (in s). -1 K is the consistency coefficient, and n is the non-Newtonian exponent. Taking the logarithm of both sides of the above formula, we obtain a set of (lnη)... a The non-Newtonian exponent is obtained by performing a logarithmic transformation and fitting on the experimentally measured data (lnγ).

[0028] The melt viscosity range of the liquid crystal polymer of this invention is 10-80 Pa·s. Testing was performed using a Dynisco LCR7000 capillary rheometer at a temperature 20°C above the melt temperature and a shear rate of 1000 s⁻¹. -1 Data were obtained by preheating a die with an inner diameter of 1 mm and a length of 40 mm for 4 minutes.

[0029] The preferred preparation method of the liquid crystal polymer of the present invention includes the following steps:

[0030] (1) Acetylation stage: Add each monomer, acylation agent and catalyst to the reactor and acylate at 130-200℃ for 0.5-8 hours;

[0031] (2) Melt polycondensation stage: The temperature is increased to 180-350℃ at a heating rate of 0.5-3℃ / min to carry out the melt polycondensation reaction. During the process, the acylation by-product acid is distilled off. The reaction ends when the melt viscosity of the prepolymer melt reaches 0.1-5 Pa.s.

[0032] (3) Prepolymer melt discharge stage: The melt is discharged at 250-280℃ and spread, cooled and solidified in the cooling equipment to form a solid layer of liquid crystal polymer;

[0033] (4) Crushing stage: The above solid layer is crushed to obtain powder with an average particle size of 2-35 μm;

[0034] (5) Thickening stage: The powder from the above stage is subjected to a solid-phase thickening reaction in an inert gas atmosphere. The reaction temperature is 230-340℃ and the reaction time is 10min-35h to obtain the liquid crystal polymer.

[0035] The preferred preparation method of the liquid crystal polymer can further reduce the non-Newtonian index.

[0036] In another embodiment of the liquid crystal polymer of the present invention, the following steps are included:

[0037] (1) Acetylation stage: The monomers, acylation agents and catalysts corresponding to the -O-Ar1-CO- units, -O-Ar2-CO- units, -O-Ar4-O- units and -Y-Ar5-Z- units are respectively added to the first reactor and reacted at 100-160℃ for 0.5-5h;

[0038] (2) Polycondensation section: The acetylated reactants are transferred to the second reactor and melt-polymerized with the monomers corresponding to the -CO-Ar3-CO- unit. The temperature is increased to 275-285℃ at a heating rate of 0.3-1.5℃ / min. The heating rate is controlled so that the heating time in the 280-300℃ heating section is maintained at 1-3h. Finally, the temperature is increased to 10-30℃ above the melting point at a heating rate of 0.3-1.5℃ / min. Acetic acid and its by-products are continuously distilled off during the heating process.

[0039] (3) Reduced pressure polymerization section: The second reactor is subjected to reduced pressure polymerization with a target vacuum of 0.1 kPa to 40 kPa. The reduced pressure polymerization time is controlled within 3 hours. Finally, the temperature of the prepolymer melt at discharge is controlled to be 10 to 30°C above the melting point. After the target stirring power is reached, the melt is discharged in a molten state. After cooling, it is cut or crushed to obtain the liquid crystal polymer.

[0040] In the above preparation process, the molar ratio of the acylating agent to the total molar amount of phenolic hydroxyl groups in the monomer is (1-1.2):1; the acylating agent is selected from any one of acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, 2-ethylhexanoic anhydride, dichloroacetic anhydride, or difluoroacetic anhydride; the amount of catalyst added is 20-2000 ppm of the theoretical output; the catalyst is selected from organic imidazole compounds; the organic imidazole compounds are selected from any one of 1-methylimidazolium, 2-methylimidazolium, 4-methylimidazolium, 1-ethylimidazolium, 2-ethylimidazolium, 4-ethylimidazolium, 1,2-dimethylimidazolium, 1,4-dimethylimidazolium, 2,4-dimethylimidazolium, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide.

[0041] A liquid crystal polymer composite material, by weight, comprises the following components:

[0042] 45-78 parts of the liquid crystal polymer of the present invention;

[0043] 22-55 parts of reinforcing material.

[0044] The non-Newtonian index of the liquid crystal polymer composite material is less than 0.85.

[0045] Preferably, the non-Newtonian index of the liquid crystal polymer composite material is in the range of 0.33-0.84.

[0046] The content of the liquid crystal polymer in this invention can be 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 78 parts, etc., and the content of the reinforcing material can be 22 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, etc. In the liquid crystal polymer composite material of this invention, the liquid crystal polymer accounts for not less than 40 wt% of the total weight.

[0047] The reinforcing material is selected from at least one of fibrous reinforcing fillers and granular reinforcing fillers;

[0048] This invention does not limit the parameters of the reinforcing material. The aspect ratio of the fibrous filler can be 600:1 to 100:1, and the average particle size of the granular reinforcing filler can be less than 100 micrometers.

[0049] The fibrous reinforcing filler is selected from at least one of glass fiber, potassium titanate fiber, ceramic fiber, wollastonite fiber, metal carbide fiber, metal-cured fiber, asbestos fiber, alumina fiber, silicon carbide fiber, gypsum fiber, boron fiber, potassium titanate whiskers, zinc oxide whiskers, and aluminum borate whiskers; the granular reinforcing filler is selected from at least one of talc, carbon black, gypsum, asbestos, zeolite, sericite, kaolin, montmorillonite, clay, lithium montmorillonite, synthetic mica, aluminosilicate, silicon dioxide, titanium oxide, alumina, zinc oxide, zirconium oxide, iron oxide, magnesium titanate, dolomite, aluminum sulfate, barium sulfate, magnesium sulfate, calcium carbonate, mica, quartz powder, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass beads, ceramic beads, boron nitride, and silicon carbide.

[0050] Those skilled in the art may choose to add 0-2 parts of an additive based on the actual situation. The additive is selected from one or more of antioxidants, lubricants, and UV stabilizers.

[0051] The present invention also provides an imaging module component, which is made using the liquid crystal polymer composite material of the present invention, particularly an imaging module for a camera.

[0052] The present invention has the following beneficial effects:

[0053] The molecular chains of liquid crystal polymers (LCPs) have rigid or semi-rigid rod-like structures, and in the molten state, they spontaneously form ordered liquid crystal phases (such as nematic or smectic phases). When LCPs are subjected to shear forces, their microstructure undergoes significant changes, directly leading to a fluid thinning effect. The non-Newtonian index reflects the molecular weight distribution and flowability of the material, further demonstrating differences in molding, and also affects the orientation of micro-molecules during molding, further influencing the material's ductility. The non-Newtonian index of the liquid crystal polymer of this invention is less than 0.75, and the non-Newtonian index of the filled liquid crystal polymer composite material is also less than 0.85. Combined with the specific repeating units of this invention, the liquid crystal polymer composite material of this invention exhibits good ductility and excellent thin-walled molding properties, making it suitable for imaging modules with a thickness of less than 0.1 mm. Detailed Implementation

[0054] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0055] The raw materials used in this invention are sourced from the following sources:

[0056] 4-Hydroxybenzoic acid: Sigma-Aldrich, purity >99%;

[0057] 2-Hydroxy-6-naphthoic acid: Sigma-Aldrich, purity >99%;

[0058] Terephthalic acid: Sigma-Aldrich, purity >99%;

[0059] 4,4'-Biphenyl dicarboxylic acid: Sigma-Aldrich, purity >99%;

[0060] 4,4'-Dihydroxybiphenyl: Sigma-Aldrich, purity >99%;

[0061] Hydroquinone: Sigma-Aldrich, purity >99%;

[0062] 4-Acetaminophen: Sigma-Aldrich, purity >99%;

[0063] p-Aminophenol: Sigma-Aldrich, purity >99%;

[0064] Fiberglass: Purchased from Owens Corning.

[0065] Preparation methods of liquid crystal polymers in Examples 1-10 and Comparative Examples 1-3 / 6 / 7: Monomers, acylation agents, and catalysts were added to a reactor and acylated at 150°C for 4 hours. The temperature was then increased to 180-350°C at a rate of 1.5°C / min for melt polycondensation, during which the acylation byproduct acid was distilled off. The melt viscosity of the prepolymer melt was controlled between 1-5 Pa·s until the reaction was complete. The melt was discharged at 250-280°C and spread, cooled, and solidified in a cooling device to form a solid layer of liquid crystal polymer. This solid layer was pulverized to obtain powder with a particle size of 2-35 μm. The powder from the above stage was subjected to a solid-phase thickening reaction in an inert gas atmosphere at a reaction temperature of 300°C for 12 hours to obtain the liquid crystal polymer.

[0066] Preparation methods of liquid crystal polymers in Examples 11-13 and Comparative Example 4 / 5: Monomers, acylating agents, and catalysts corresponding to the -O-Ar1-CO-, -O-Ar2-CO-, -O-Ar4-O-, and -Y-Ar5-Z- units, respectively, were added to a first reactor and reacted at 120°C for 3 hours. The acetylated reactants were then transferred to a second reactor and melt-polymerized with the monomers corresponding to the -CO-Ar3-CO- units, with the temperature increased to 275-285°C at a heating rate of 0.8°C / min. Then, the heating rate is controlled to maintain the heating time in the 280-300℃ heating range for 2 hours. Finally, the heating rate is continued at 1℃ / min to raise the temperature to 20℃ above the melting point. Acetic acid and its by-products are continuously distilled off during the heating process. The second reactor is subjected to decompression polymerization with a target vacuum of about 1 kPa and a decompression polymerization time of 2 hours. Finally, the temperature of the prepolymer melt at discharge is controlled to be 10-30℃ above the melting point. After reaching the target stirring power, the melt is discharged in a molten state, cooled, and then cut or crushed to obtain the liquid crystal polymer.

[0067] Test methods:

[0068] (1) Non-Newtonian index: Tested using a Dynisco LCR7000 capillary rheometer at a temperature 20°C above the melting point and a shear rate of 500-5000 s. -1 Data was obtained using a die with an inner diameter of 1 mm and a length of 40 mm, after preheating for 4 minutes. The Newtonian form of the power-law model is η. a =Kγ n-1 , where η a γ is the apparent shear viscosity (in Pa·s), and γ is the shear rate (in s). -1 K is the consistency coefficient, and n is the non-Newtonian exponent. Taking the logarithm of both sides of the above formula, we obtain a set of (lnη)... a The non-Newtonian exponent is obtained by performing a logarithmic transformation and fitting on the experimentally measured data (lnγ).

[0069] (2) Melt viscosity: Tested using a Dynisco LCR7000 capillary rheometer at a temperature 20°C above the melting temperature and a shear rate of 1000 s. -1 Data were obtained by preheating a die with an inner diameter of 1 mm and a length of 40 mm for 4 minutes.

[0070] (3) Formability of thin-walled parts: At a melting temperature 5°C above the liquid crystal polyester composition and an injection speed of 60 mm / s, the liquid crystal polyester composition was formed into sheet-like samples with a thickness of 0.1 mm and a length and width of 60 mm. 100 sheet-like samples were placed under a two-dimensional imaging instrument and observed at a magnification of 100x to assess whether shape defects (filler agglomeration and notches) appeared in the thin-walled parts. Filler agglomeration rate = number of samples with filler agglomeration / total number of samples * 100%; Notch rate = number of samples with notches / total number of samples * 100%.

[0071] (4) Flexibility: The material's deflection was used for evaluation, measured according to ISO 178-2019 standard, with test conditions of 23℃ and 2mm / min. Higher deflection indicates better flexibility of the liquid crystal polymer or its composite material.

[0072] Table 1: Content and Test Results of Monomers in Liquid Crystal Polymers in Examples 1-7

[0073] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 4-Hydroxybenzoic acid mol% 56 58 62 64 65 58 58 2-Hydroxy-6-naphthoic acid mol% 8 4 8 2 8 4 4 terephthalic acid mol% 18 19 15 17 13.5 19 4,4'-Biphenyldicarboxylic acid mol% 19 4,4'-Dihydroxybiphenyl mol% 15 2,6-Naphthyldiol mol% 10 15 7 15 5.5 15 p-Aminophenol mol% 8 4 8 2 8 4 4 Product melt viscosity (Pa.s) 25.3 27.7 31.0 29.2 28.6 27.0 27.5 Non-Newtonian exponent 0.26 0.17 0.22 0.29 0.35 0.60 0.48

[0074] As can be seen from Examples 2 / 6-10, when monomers are preferred within the range of repeating unit content of the present invention, they have a higher non-Newtonian index.

[0075] Table 2: Content and Test Results of Monomers in Liquid Crystal Polymers in Examples 8-13

[0076] Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 4-Hydroxybenzoic acid mol% 58 58 58 58 58 55 2-Hydroxy-6-naphthoic acid mol% 4 4 4 4 4 7 terephthalic acid mol% 19 19 19 19 19 4,4'-Biphenyldicarboxylic acid mol% 19 hydroquinone mol% 15 15 2,6-Naphthyldiol mol% 15 15 15 15 4-Acetaminophen mol% 4 p-Aminophenol mol% 4 4 6-Acetamino-2-naphthol mol% 4 4 4 Product melt viscosity (Pa.s) 27.3 27.7 27.0 27.7 26.9 27.4 Non-Newtonian exponent 0.51 0.52 0.55 0.57 0.71 0.62

[0077] Table 3: Content and Test Results of Monomers in Liquid Crystal Polymers in Comparative Examples 1-7

[0078] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 4-Hydroxybenzoic acid mol% 53 56 68 68 58 73 55 2-Hydroxy-6-naphthoic acid mol% 9 2 6 6 4 27 7 terephthalic acid mol% 19 4,4'-Biphenyldicarboxylic acid mol% 19 terephthalic acid mol% 19 21 13 13 hydroquinone mol% 15 2,6-Naphthyldiol mol% 15 11 7 7 15 p-Aminophenol mol% 4 10 6 6 4 4-Acetaminophen mol% 4 Product melt viscosity (Pa.s) 27.5 27.2 27.4 28.0 26.9 23.7 26.8 Non-Newtonian exponent 0.80 0.89 0.85 0.92 0.79 0.68 0.83

[0079] Preparation method of liquid crystal polymer composite material in the examples and comparative examples: Liquid crystal polymer and glass fiber are mixed evenly and extruded through a twin-screw extruder. The maximum temperature of the screw is set 5-30°C higher than the melting point of the resin, and the speed is 100-500 rpm to obtain liquid crystal polymer composite material.

[0080] Table 4: Component content and test results of liquid crystal polymer composite materials in Examples A1-A12 and Comparative Examples B1-B6

[0081] Example A1 Example A2 Example A3 Example A4 Example A5 Example A6 Example A7 Liquid crystal polymer 1 2 3 4 5 6 7 Liquid crystal polymer, 60 60 60 60 60 60 60 Fiberglass, 40 40 40 40 40 40 40 Non-Newtonian exponent 0.48 0.34 0.43 0.44 0.52 0.74 0.62 Packing agglomeration rate, % 0 0 0 0 0 0 0 Gap rate, % 0 0 0 0 0 0 0 Deflection, mm 6.1 6.7 6.5 5.5 4.9 3.6 4.1

[0082] Continued from Table 4:

[0083] Example A8 Example A9 Example A10 Example A11 Example A12 Example A13 Liquid crystal polymer 8 9 10 11 12 13 Liquid crystal polymer, 60 60 60 60 60 60 Fiberglass, 40 40 40 40 40 40 Non-Newtonian exponent 0.63 0.70 0.71 0.73 0.83 0.74 Packing agglomeration rate, % 0 0 0 0 2 0 Gap rate, % 0 0 0 0 5 1 Deflection, mm 3.7 3.9 3.5 3.6 3.0 3.2

[0084] As can be seen from Examples A2 / A6-A10, when the monomer is preferably selected within the range of repeating unit content of the present invention, the liquid crystal polymer has a lower non-Newtonian index, and the composite material made therefrom also has better ductility.

[0085] As can be seen from the comparison between Examples A2 / A6 / A11 / A12 and Comparative Examples B3 / B4, the liquid crystal polymer obtained by using the preferred preparation process has a lower non-Newtonian index, and the composite material made from it also has better ductility.

[0086] Continued from Table 4:

[0087] Comparative Example B1 Comparative Example B2 Comparative Example B3 Comparative Example B4 Comparative Example B5 Comparative Example B6 Comparative Example B7 Liquid crystal polymer 14 15 16 17 18 19 20 Liquid crystal polymer, 60 60 60 60 60 60 60 Fiberglass, 40 40 40 40 40 40 40 Non-Newtonian exponent 0.87 0.94 0.90 0.98 0.91 0.80 0.91 Packing agglomeration rate, % 8 25 11 34 27 13 22 Gap rate, % 10 28 12 40 33 24 29 Deflection, mm 2.7 2.0 2.3 1.8 2.5 2.4 2.7

[0088] As can be seen from comparative examples B1-B7, when the non-Newtonian index is too high, not only is the thin-wall forming effect poor, but the ductility is also insufficient.

[0089] As can be seen from the above examples and comparative examples, when the non-Newton coefficient of the liquid crystal polymer is less than 0.75, the non-Newton coefficient of the composite material after inorganic filling is less than 0.85, the filler agglomeration rate is less than 3%, the notch rate is less than 6%, and the deflection is >2.9mm.

Claims

1. A liquid crystal polymer, characterized in that, The liquid crystal polymer has a non-Newtonian index of less than 0.75 and, based on molar content, is derived from the following repeating units: -O-Ar1-CO- unit 55-65 mol%; -O-Ar2-CO-unit 2-8mol%; -CO-Ar3-CO- unit 12-20 mol%; -O-Ar4-O-unit 5-15mol%; -Y-Ar5-Z-unit 2-8mol%; The -O-Ar1-CO- unit is derived from 4-hydroxybenzoic acid; The -O-Ar2-CO- unit is derived from 2-hydroxy-6-naphthoic acid; The -CO-Ar3-CO- unit is derived from at least one of terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid; The -O-Ar4-O- unit is derived from at least one of 4,4'-dihydroxybiphenyl, hydroquinone, and 2,6-naphthol; When a naphthyl unit is present in the -CO-Ar3-CO- unit and / or the -O-Ar4-O- unit, the -Y-Ar5-Z- unit is derived from at least one of 4-acetaminophen, p-aminophenol, and 6-acetamino-2-naphthol. When the molar content of naphthyl units in the liquid crystal polymer is ≥4 mol% and there are no naphthyl units in either the -CO-Ar3-CO- unit or the -O-Ar4-O- unit, the -Y-Ar5-Z- unit is derived from at least one of p-aminophenol, 4'-amino-4-biphenol, and 6-acetamido-2-naphthol.

2. The liquid crystal polymer according to claim 1, characterized in that, The non-Newtonian index of the liquid crystal polymer is less than 0.60; preferably, the non-Newtonian index of the liquid crystal polymer is less than 0.

40.

3. The liquid crystal polymer according to claim 1, characterized in that, The -CO-Ar3-CO- unit is derived from terephthalic acid, the -O-Ar4-O- unit is derived from 2,6-naphthol, and the -Y-Ar5-Z- unit is derived from p-aminophenol.

4. The liquid crystal polymer according to claim 1, characterized in that, The melt viscosity range of the liquid crystal polymer is 10-80 Pa·s.

5. The method for preparing the liquid crystal polymer according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Acetylation stage: Add each monomer, acylation agent and catalyst to the reactor and acylate at 130-200℃ for 0.5-8 hours; (2) Melt polycondensation stage: The temperature is increased to 180-350℃ at a heating rate of 0.5-3℃ / min to carry out the melt polycondensation reaction. During the process, the acylation byproduct acid is distilled off. The reaction ends when the melt viscosity of the prepolymer melt reaches 0.1-5 Pa.s. (3) Prepolymer melt discharge stage: The melt is discharged at 250-280℃ and spread, cooled and solidified in the cooling equipment to form a solid layer of liquid crystal polymer; (4) Crushing stage: The above solid layer is crushed to obtain powder with an average particle size of 2-35 micrometers; (5) Thickening stage: The powder from the above stage is subjected to a solid-phase thickening reaction in an inert gas atmosphere. The reaction temperature is 230-340℃ and the reaction time is 10min-35h to obtain the liquid crystal polymer.

6. The method for preparing the liquid crystal polymer according to claim 5, characterized in that, The molar ratio of the acylating agent to the total molar amount of phenolic hydroxyl groups in the monomer is (1-1.2):1; the acylating agent is selected from any one of acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, 2-ethylhexanoic anhydride, dichloroacetic anhydride, or difluoroacetic anhydride; the amount of catalyst added is 20-2000 ppm of the theoretical output; the catalyst is selected from organic imidazole compounds; the organic imidazole compounds are selected from any one of 1-methylimidazolium, 2-methylimidazolium, 4-methylimidazolium, 1-ethylimidazolium, 2-ethylimidazolium, 4-ethylimidazolium, 1,2-dimethylimidazolium, 1,4-dimethylimidazolium, 2,4-dimethylimidazolium, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide.

7. A liquid crystal polymer composite material, characterized in that, By weight, it includes the following components: 45-78 parts of the liquid crystal polymer according to any one of claims 1-4; 22-55 parts of reinforcing material.

8. The liquid crystal polymer composite material according to claim 7, characterized in that, The non-Newtonian index of the liquid crystal polymer composite material is less than 0.

85.

9. The liquid crystal polymer composite material according to claim 7, characterized in that, The reinforcing material is selected from at least one of fibrous reinforcing fillers and granular reinforcing fillers; the fibrous reinforcing filler is selected from at least one of glass fiber, potassium titanate fiber, ceramic fiber, wollastonite fiber, metal carbide fiber, metal-cured fiber, asbestos fiber, alumina fiber, silicon carbide fiber, gypsum fiber, boron fiber, potassium titanate whiskers, zinc oxide whiskers, and aluminum borate whiskers; the granular reinforcing filler is selected from at least one of talc, carbon black, gypsum, asbestos, zeolite, sericite, kaolin, montmorillonite, clay, lithium montmorillonite, synthetic mica, aluminosilicate, silicon dioxide, titanium oxide, alumina, zinc oxide, zirconium oxide, iron oxide, magnesium titanate, dolomite, aluminum sulfate, barium sulfate, magnesium sulfate, calcium carbonate, mica, quartz powder, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass beads, ceramic beads, boron nitride, and silicon carbide.

10. An imaging module component, characterized in that, It is prepared using the liquid crystal polymer composite material as described in claim 7 or 8.