Preparation method and application for enhancing spinning capability of LCP (Liquid Crystal Polymer)

Abstract

The invention discloses a preparation method for enhancing the spinning capability of LCP (Liquid Crystal Polymer) and application. The method comprises the following steps: firstly, carrying out acetylation reaction on p-phenylenediamine, terephthaloyl chloride, p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, acetic anhydride and 4, 4-biphenol to obtain a mixture of aromatic polyamide and acetylated monomers; carrying out ester exchange on the obtained S1 mixture and phenolphthalein under the action of a catalyst to obtain a mixture of liquid crystal copolyester and aromatic polyamide; finally, heating the mixture material of the liquid crystal copolyester and the aromatic polyamide; and extruding to obtain the functional master batch. Furthermore, the functional master batch can be prepared into the modified liquid crystal LCP fiber. According to the method, the LCP spinning process is simplified, while the product quality is guaranteed, the filamentation efficiency of liquid crystal macromolecules is improved, the production process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology of high-performance liquid crystal polymers (LCPs), specifically relating to a preparation method and application for enhancing the spinning ability of LCPs. Background Technology

[0002] Liquid crystal polyester (LCP) is a high-end engineering plastic with properties that can be described as a "contradictory combination." Its most remarkable characteristic is that its molecules maintain a crystalline, ordered arrangement even in the molten state, giving it unparalleled comprehensive properties. In terms of mechanical properties, its strength and stiffness are comparable to many metals, while its texture is lightweight. In terms of heat resistance, it can easily withstand prolonged high temperatures exceeding 200 degrees Celsius and inherently possesses excellent flame retardancy. More uniquely, it exhibits outstanding resistance to most acids, alkalis, and solvents, and boasts the lowest hygroscopicity of all engineering plastics, absorbing almost no moisture, thus maintaining excellent dimensional stability in humid environments. Furthermore, its dielectric properties at high frequencies are also excellent. It is these extraordinary properties that allow LCP to quietly yet profoundly permeate and drive many aspects of our social life. In the field of electronic communications, it is an indispensable cornerstone of the 5G era. Precision connectors made from LCP can withstand the high temperatures of soldering mobile phone circuit boards, while flexible circuit boards and antenna materials ensure high-speed, low-loss transmission of high-frequency signals, directly improving our communication quality and speed. In the aerospace and automotive industries, its fiber-reinforced composites are used to manufacture lighter, stronger components, effectively achieving weight reduction and energy saving, while its high-temperature resistance also improves the reliability of engine-related parts. In high-end protection, bulletproof vests and helmets made from LCP fibers, with their superior specific strength and impact resistance compared to traditional materials, provide law enforcement and security personnel with lighter and safer life protection. Even in the medical field, its biocompatibility and ability to withstand high-temperature and high-pressure sterilization make it an ideal material for precision surgical instruments and sterilization trays. In a sense, LCP, as a behind-the-scenes hero material, comprehensively improves the technological level and safety of modern life by making electronic devices smaller and more reliable, vehicles lighter, safety protection more effective, and medical technology more advanced.

[0003] LCP possesses extremely high mechanical strength, excellent heat resistance (long-term operating temperature exceeding 200°C), inherent flame retardancy, extremely low moisture absorption, and superior chemical stability, making it an irreplaceable key material in high-temperature, high-frequency 5G communications and precision electronics. However, its significant drawback lies in its strong anisotropy, resulting in weak strength perpendicular to the flow direction and susceptibility to warping. Furthermore, its smooth and chemically inert surface presents challenges for bonding and printing. The core significance of LCP spinning lies in its successful utilization of the inherent superior properties of liquid crystal polyester in macroscopic bulk materials through an actively controlled drawing process, maximizing its fiber morphology. This transformation not only overcomes the anisotropy drawbacks of LCP injection molded parts but also leverages the highly oriented characteristics of its rigid rod-shaped molecular chains during melt spinning to create top-tier fibers possessing unparalleled mechanical properties, excellent heat resistance, extremely low moisture absorption, and superior chemical stability. Through spinning, LCP has been transformed from a high-performance engineering plastic into an indispensable strategic material in aerospace, high-end protection, 5G / 6G communications, and other fields. This allows it to be used in lightweight, high-strength linear or woven forms to manufacture cutting-edge products such as bulletproof equipment, composite materials, and flexible circuit board antennas, fully unleashing its enormous potential to solve technical challenges in extreme environments and enhancing the industrial application value of LCP.

[0004] To prepare high-performance LCP fibers and meet the needs of the rapid development of 5G, various industries have made many attempts. For example, patent CN111101256A discloses a liquid crystal polymer fabric and its preparation method. Liquid crystal polymer fibers are prepared by melt spinning, and liquid crystal polymer fabric is prepared by weaving. The liquid crystal polymer fabric has the characteristics of good strength, uniform thickness, low dielectric constant and low dielectric loss factor.

[0005] For example, patent CN202211127178 discloses a liquid crystal polyester fabric for preparing low dielectric and high peel strength PCB copper-clad laminate. The liquid crystal polymer fiber is prepared by melt spinning and the liquid crystal polymer fabric is prepared by weaving. The liquid crystal polymer fabric is spun by a mixed melt spinning method.

[0006] All of the above patents utilize the method of melting liquid crystal polymers with other polymer materials, but the filamentation efficiency needs to be improved. Summary of the Invention

[0007] To address the aforementioned problems, this invention proposes a preparation method and application for enhancing the spinning capability of LCP. It utilizes a one-pot method to produce raw materials for fiber drawing, simplifying the LCP spinning process. While ensuring product quality, it improves the fiber-forming efficiency of liquid crystal polymers, simplifies the production process, and reduces production costs.

[0008] The above objectives are achieved through the following technical solutions: This invention first provides a method for preparing materials to enhance the spinning ability of LCP, the method comprising the following steps: S1. P-phenylenediamine, terephthaloyl chloride, p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, acetic anhydride and 4,4-biphenyldiol are subjected to an acetylation reaction to obtain a mixture of polyarylamide and acetylated monomers; S2. The obtained S1 mixture is subjected to transesterification with phenolphthalein under the action of a catalyst to obtain a mixture of liquid crystal copolyester and polyarylamide; S3. Heat the mixture of liquid crystal copolyester and polyaramid to a higher temperature; S4. Extrude the mixture of liquid crystal copolyester and polyaramid to obtain functional masterbatch.

[0009] In step S1, the molar ratio of p-phenylenediamine, terephthaloyl chloride, p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4,4-biphenylhydrazine, and acetic anhydride is 0.01-0.1:0.01-0.1:1:1-3:2-4:5-8; In step S1, the conditions for the acetylation reaction are: stirring at 150-200℃ for 1-3 hours under nitrogen atmosphere, followed by stirring in an ice-water bath for 0.5-2 hours.

[0010] In step S2, the transesterification reaction includes: mixing the polyarylamide and acetylated monomer mixture obtained in step S1, phenolphthalein and catalyst, and carrying out the transesterification reaction to obtain liquid crystal copolyester and polyarylamide; the molar ratio of the polyarylamide and acetylated monomer mixture to phenolphthalein is 2-5:1.

[0011] In step S2, the catalyst is at least one of zinc acetate, sodium acetate, magnesium acetate, and potassium acetate; the catalyst accounts for 1-2‰ of the mass of the mixture of polyarylamide and acetylated monomer.

[0012] In step S2, the transesterification reaction conditions include: reacting at 100-200℃ for 1-3 hours under nitrogen, then reacting at 200-280℃ for 1-4 hours, and finally reacting at 300-330℃ under vacuum of 10-30 Pa for 1-3 hours.

[0013] In step S3, the mixture of liquid crystal copolyester and polyaramid is heated to 250-350°C to melt.

[0014] In step S4, the single- and twin-screw extrusion process of the mixture of liquid crystal copolyester and polyaramid is as follows: extrusion temperature is 250℃~350℃, main screw speed is 400~600r / min, and water bath temperature is 30℃~60℃.

[0015] This invention further provides an application of LCP functional masterbatch, which is used to prepare modified liquid crystal LCP fibers. The specific process parameters are as follows: masterbatch drying temperature 80℃~150℃, vacuum degree 10~30Pa, drying time 12~24 hours; spinning process: spinning machine screw temperature 250~350℃, spinning die temperature 250~350℃, drawing roller temperature 70~120℃, spinning tunnel temperature 150~250℃, metering pump frequency 10~50HZ, spinning speed 500m / min~2000m / min, and draw ratio 1.0~1.5 times.

[0016] The beneficial effects of this invention are: 1. Starting from macromolecular structure design, this invention develops a novel liquid crystal polyester and polyaramid copolymer. By using this functional masterbatch to modify conventional spinning-grade liquid crystal LCP polyester, high-performance liquid crystal polyester fibers can be synthesized in one pot, replacing the traditional multi-step melt spinning scheme, greatly simplifying the LCP spinning production process and reducing process complexity.

[0017] 2. This invention, starting from the design of macromolecular structure, preferentially enriches polyaramid resin on the surface of liquid crystal polyester fibers, with a small amount distributed inside. This significantly improves the compatibility between the fiber and polyphenylene ether resin while maximizing the preservation of the excellent mechanical properties (such as strength and stiffness) of the LCP fiber itself, avoiding the adverse effects of functional additives on spinnability. A novel liquid crystal polyester-polyaramid copolymer is developed, and conventional spinning-grade LCP is modified with functional masterbatch to effectively improve its spinning ability and overcome the molding instability problem that easily occurs in the traditional LCP spinning process. It also improves the inherent anisotropy defects of LCP materials, reduces the problem of insufficient strength in the vertical flow direction, and enhances the adhesion compatibility of the material, broadening its application scenarios. Detailed Implementation

[0018] Example 1:

[0019] S1. Preparation of polyarylamide and acetylated monomers: 0.05 mol p-phenylenediamine, 0.05 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0020] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0021] S3. Preparation of Masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0022] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the functional masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm and a weft density of 15 / cm.

[0023] Example 2:

[0024] S1. Preparation of polyarylamide and acetylated monomers: 0.02 mol p-phenylenediamine, 0.02 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0025] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0026] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0027] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0028] Example 3:

[0029] S1. Preparation of polyarylamide and acetylated monomers: 0.01 mol p-phenylenediamine, 0.01 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and stirred at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0030] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0031] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0032] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0033] Example 4:

[0034] S1. Preparation of polyarylamide and acetylated monomers: 0.08 mol p-phenylenediamine, 0.08 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0035] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0036] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0037] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0038] Example 5:

[0039] S1. Preparation of polyarylamide and acetylated monomers: 0.1 mol p-phenylenediamine, 0.1 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0040] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0041] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0042] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0043] Comparative Example 1 S1. Preparation of polyarylamide and acetylated monomer: 1 mol of p-hydroxybenzoic acid, 1 mol of 2-hydroxy-6-naphthoic acid, 2 mol of 4,4'-biphenyl, 5 mol of acetic anhydride and 10 g of superphosphoric acid were mixed and stirred at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomer.

[0044] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0045] Masterbatch preparation: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated using a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃. The functional masterbatch was obtained.

[0046] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0047] Comparative Example 2 S1. Preparation of polyarylamide and acetylated monomer: 0.02 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and stirred at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomer.

[0048] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0049] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0050] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0051] Comparative Example 3 S1. Preparation of polyarylamide and acetylated monomers: 0.02 mol p-phenylenediamine, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0052] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0053] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0054] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0055] Comparative Example 4 S1. Preparation of polyarylamide and acetylated monomers: 0.01 mol p-phenylenediamine, 0.02 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0056] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0057] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0058] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0059] Comparative Example 5 S1. Preparation of polyarylamide and acetylated monomers: 0.02 mol p-phenylenediamine, 0.01 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0060] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0061] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0062] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0063] Comparative Example 6 S1. Preparation of polyarylamide and acetylated monomers: 0.04 mol p-phenylenediamine, 0.01 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and reacted at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0064] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0065] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0066] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0067] Comparative Example 7 S1. Preparation of polyarylamide and acetylated monomers: 0.01 mol p-phenylenediamine, 0.04 mol terephthaloyl chloride, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 1 mol p-hydroxybenzoic acid, 1 mol 2-hydroxy-6-naphthoic acid, 2 mol 4,4'-biphenylhydrazine, 5 mol acetic anhydride and 10 g superphosphoric acid were mixed and stirred at 150 °C for 1 h under a nitrogen atmosphere. After the reaction was completed, the mixture was transferred to an ice-water bath and stirred for another 2 h to obtain a mixture of polyarylamide and acetylated monomers.

[0068] S2. Synthesis of liquid crystal copolyester and polyarylamide: 2 mol of the polyarylamide and acetylated monomer mixture obtained in step S1, 1 mol of phenolphthalein and 1 g of sodium acetate were mixed and reacted at 150 °C for 3 h in a nitrogen atmosphere, then the temperature was raised to 200 °C and the reaction continued for 4 h, and finally the temperature was raised to 330 °C under a vacuum of 10 Pa and the reaction was carried out for 1 h to complete the transesterification reaction and obtain liquid crystal copolyester and polyarylamide.

[0069] Preparation of masterbatch: The obtained liquid crystal copolyester and polyaramid were heated to 280℃ to melt, and then co-extruded and granulated through a twin-screw extruder. The screw extrusion temperature was set to the resin melting point +15℃, the main screw speed was controlled at 500-550 r / min, and the water bath temperature was maintained at 30-60℃ to obtain the functional masterbatch.

[0070] Furthermore, the obtained functional masterbatch was used to prepare modified liquid crystal polyester fabric: the masterbatch was vacuum dried and then spun into blended yarns. The yarns were then melt-spun using a single- or twin-screw spinning machine to obtain modified liquid crystal polyester fibers. Subsequently, the obtained fibers were processed into liquid crystal polyester fabrics for low dielectric strength through a weaving process, with both warp and weft densities controlled at 15 / cm, and the weft density at 15 / cm.

[0071] Table 1. Mechanical properties and spinnability analysis of LCP liquid crystal polyester fibers in Examples 1-5 and Comparative Examples 1-3. Serial Number Melting point (°C) of spinning-grade LCP resin Content of polyarylamide (%) LCP spinning melt viscosity (Pa·s) Fiber strength (cN / dtex) Fiber elongation Example 1 270 5 50 11.6 5.6 Example 2 270 2 50 11.8 5.0 Example 3 280 1 50 10.3 5.5 Example 4 270 8 50 10.2 5.6 Example 5 260 10 50 10.1 5.2 Comparative Example 1 280 - 50 11.3 4.1 Comparative Example 2 270 - 50 10.7 3.2 Comparative Example 3 280 - 50 11.1 4.1 Comparative Example 4 270 - 50 10.7 3.1 Comparative Example 5 280 - 50 10.8 3.1 Comparative Example 6 280 - 50 11.0 3.4 Comparative Example 7 270 - 50 11.0 3.4 Table 1 shows the mechanical properties and spinnability evaluation of LCP liquid crystal polyester fibers in Examples 1-5 and Comparative Examples 1-3. Analysis of the test data results shows that, compared with Comparative Example 2, this technical solution greatly improves the spinnability of the modified LCP liquid crystal resin and the mechanical properties of the prepared modified fiber. Compared with the conventional spinning-grade liquid crystal LCP polyester in Comparative Example 1, the spinnability of the modified LCP liquid crystal polyester prepared by this technical solution is improved, and the mechanical properties of the modified fiber are basically not much changed.

[0072] The comparison between Examples 4-7 showed that the effect was best when the ratio of p-phenylenediamine to terephthaloyl chloride was 1:1.

[0073] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any improvements or modifications made by those skilled in the art to the above description without departing from the essence of the present invention should fall within the protection scope of the appended claims.

Claims

1. A method for preparing materials to enhance the spinning ability of LCP, characterized in that, The method includes the following steps: S1. P-phenylenediamine, terephthaloyl chloride, p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, acetic anhydride and 4,4-biphenyldiol are subjected to an acetylation reaction to obtain a mixture of polyarylamide and acetylated monomers; S2. The obtained S1 mixture is subjected to transesterification with phenolphthalein under the action of a catalyst to obtain a mixture of liquid crystal copolyester and polyarylamide; S3. Heat the mixture of liquid crystal copolyester and polyaramid to a higher temperature; S4. Extrude the mixture of liquid crystal copolyester and polyaramid to obtain functional masterbatch.

2. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S1, the molar ratio of p-phenylenediamine, terephthaloyl chloride, p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4,4-biphenylhydrazine, and acetic anhydride is 0.01-0.1:0.01-0.1:1:1-3:2-4:5-8.

3. The preparation method for enhancing LCP spinning ability according to claim 1 or 2, characterized in that, In step S1, the conditions for the acetylation reaction are: stirring at 150-200℃ for 1-3 hours under nitrogen atmosphere, followed by stirring in an ice-water bath for 0.5-2 hours.

4. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S2, the transesterification reaction includes: mixing the polyarylamide and acetylated monomer mixture obtained in step S1, phenolphthalein and catalyst, and carrying out the transesterification reaction to obtain liquid crystal copolyester and polyarylamide; the molar ratio of the polyarylamide and acetylated monomer mixture to phenolphthalein is 2-5:

1.

5. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S2, the catalyst is at least one of zinc acetate, sodium acetate, magnesium acetate, and potassium acetate; the catalyst accounts for 1-2‰ of the mass of the mixture of polyarylamide and acetylated monomer.

6. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S2, the transesterification reaction conditions include: reacting at 100-200℃ for 1-3 hours under nitrogen, then reacting at 200-280℃ for 1-4 hours, and finally reacting at 300-330℃ under vacuum of 10-30 Pa for 1-3 hours.

7. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S3, the mixture of liquid crystal copolyester and polyaramid is heated to 250-350°C to melt.

8. The preparation method for enhancing LCP spinning ability according to claim 1, characterized in that, In step S4, the single- and twin-screw extrusion process of the mixture of liquid crystal copolyester and polyaramid is as follows: extrusion temperature is 250℃~350℃, main screw speed is 400~600r / min, and water bath temperature is 30℃~60℃.

9. An application of an LCP functional masterbatch, characterized in that, The functional masterbatch prepared according to any one of claims 1-8 is used to prepare modified liquid crystal LCP fibers. The specific process parameters are as follows: masterbatch drying temperature 80℃~150℃, vacuum degree 10~30Pa, drying time 12~24 hours; spinning process: spinning machine screw temperature 250~350℃, spinning die temperature 250~350℃, drawing roller temperature 70~120℃, spinning duct temperature 150~250℃, metering pump frequency 10~50HZ, spinning speed 500m / min~2000m / min, and draw ratio 1.0~1.5 times.