WO2017133448A1 - 一种液晶聚酯以及由其组成的模塑组合物和其应用 - Google Patents

一种液晶聚酯以及由其组成的模塑组合物和其应用 Download PDF

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Publication number
WO2017133448A1
WO2017133448A1 PCT/CN2017/071467 CN2017071467W WO2017133448A1 WO 2017133448 A1 WO2017133448 A1 WO 2017133448A1 CN 2017071467 W CN2017071467 W CN 2017071467W WO 2017133448 A1 WO2017133448 A1 WO 2017133448A1
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Prior art keywords
temperature
liquid crystal
crystal polyester
melting
structural unit
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PCT/CN2017/071467
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English (en)
French (fr)
Inventor
孙华伟
李闻达
肖中鹏
宋彩飞
罗德彬
许柏荣
易庆锋
周广亮
姜苏俊
曹民
曾祥斌
蔡彤旻
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金发科技股份有限公司
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Publication of WO2017133448A1 publication Critical patent/WO2017133448A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/60—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
    • C08G63/60—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
    • C08G63/605—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds the hydroxy and carboxylic groups being bound to aromatic rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/78—Preparation processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
    • C08K5/098—Metal salts of carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/02—Fibres or whiskers
    • C08K7/04—Fibres or whiskers inorganic
    • C08K7/14—Glass
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/38—Polymers
    • C09K19/3804—Polymers with mesogenic groups in the main chain
    • C09K19/3809—Polyesters; Polyester derivatives, e.g. polyamides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/20—Applications use in electrical or conductive gadgets

Definitions

  • the present invention relates to the field of polymer materials, and in particular to a liquid crystal polyester and a molding composition composed thereof and an application thereof.
  • Thermotropic Liquid Crystal Polymer is a high performance special engineering plastic with excellent mechanical properties, good fluidity, heat resistance, chemical resistance, flame retardancy and electrical insulation properties.
  • TLCP Thermotropic Liquid Crystal Polymer
  • the preparation thereof is usually carried out by a high-temperature melt polymerization method, but due to the self-polymerization of a monomer such as HBA or a branched crosslinking reaction of a molecular chain, the melt processing property and physical properties of the final liquid crystal product are poor, particularly the flow of the resin.
  • Sexuality is seriously affected, which leads to the mold filling dissatisfaction in the molding process of the liquid crystal polyester molding composition, which seriously affects the application of the liquid crystal polymer in the thin-walled parts of electronic appliances.
  • the intrinsic viscosity of liquid crystal polyesters has become a common means in the industry to characterize the relative molecular mass and molecular chain motion characteristics of liquid crystal polyesters, and indirectly reflects the fluidity of the final liquid crystal polyester.
  • the difference in intrinsic viscosity is not the only factor affecting the fluidity of the polymer.
  • the crystal structure and speed, the preparation process, etc. all have an effect on the fluidity of the polymer.
  • DSC Differential Scanning Calorimetry
  • a primary object of the present invention is to provide a liquid crystal polyester having a high fluidity, which has a double enthalpy ratio ⁇ H within a specific range and has a markedly improved process fluidity.
  • Another object of the present invention is to provide a molding composition comprising the above liquid crystal polyester.
  • a liquid crystal polyester composed of repeating structural units of the following formulas [I]-[IV]:
  • the amount of the structural unit [I] derived from p-hydroxybenzoic acid is 40 mol% or more and 80 mol% or less based on the total amount of the repeating unit 100 mol%; and the structural unit derived from 4,4'-biphenol is [II]
  • the amount is 10 mol% or more and 30 mol% or less;
  • the total amount of the structural unit [III] derived from terephthalic acid and the structural unit [IV] derived from isophthalic acid is 10 mol% or more, and 32 mol% or less;
  • the ratio of the amount of the structural unit [II] to the molar total amount of the structural unit [III] and the structural unit [IV] is 1:1, wherein the structural unit derived from isophthalic acid [IV] and derived from terephthalic acid
  • the molar ratio of the structural unit [III] is preferably 0.1 to 0.49, and the sum of the molar percentages of the structural units [I], [II], [III] and [
  • the differential scanning calorimetry DSC test is used, and the temperature is raised from room temperature to a maximum temperature of 30 ° C/min to a temperature of +30 ° C. After staying at this temperature for 3 min, the temperature is lowered to room temperature at a rate of 20 ° C/min.
  • the crystal curve of the liquid crystal polyester is obtained, and the crystallization starting temperature and the crystallization end temperature of the crystallization peak are selected, and the crystallization peak area is calculated as H (crystalline enthalpy); the test sample is kept at room temperature for 3 min and then again at 20 ° C/min.
  • the heating rate is raised to the highest temperature of the melting point +30 ° C, and the second melting curve of the liquid crystal polyester is obtained.
  • the melting initiation temperature and the melting end temperature of the melting peak are selected, and the melting peak area is calculated as H (melting enthalpy).
  • the liquid crystal polyester satisfies a double enthalpy ratio ⁇ H defined by the following formula (1) of 0.1 or more, 0.9 or less, preferably 0.2 or more and 0.7 or less;
  • ⁇ H H (melting enthalpy) / H (crystalline enthalpy).
  • the DSC double enthalpy ratio ⁇ H is the ratio of the melting enthalpy of the liquid crystal polyester crystal to the crystallization enthalpy.
  • the physical meaning of the actual reaction is the relationship between the crystal structure of the liquid crystal polyester and the ease of molecular chain crystallization and the molecular chain structure of the liquid crystal polyester.
  • Crystallization behavior The crystal melting behavior is closely related to the structural characteristics of the molecular chain. There is no interaction between the ideal molecular chains, the molecular chain structure is regular, the internal rotation ability is large, and the flexibility is high. At this time, the movement of the molecular chain has no friction and other resistance. The chain is free to move and exhibits perfect fluidity.
  • the molecular chain has high crystallinity and the crystal structure is densely packed.
  • the actual synthetic liquid crystal polyester differs in the structure or proportion of the raw material monomer, the degree of self-polymerization of the monomer, the change in molecular weight and molecular chain sequence structure, the uniformity of the molecular segment and the regularity of the molecular chain, the entanglement of the molecular chain or The degree of branching, the ability of rotation in the molecular chain, the mobility of the molecular chain, the preparation process and many other factors, which affect the molecular chain structure of the final prepared liquid crystal polyester, the molecular
  • the crystallization behavior of the chain arrangement and the destruction behavior of the crystal structure change greatly, which is manifested in the volatility of the melting enthalpy and crystallization enthalpy of DSC, and the fluctuation of this enthalpy reflects the structural characteristics of the molecular chain, and It causes a macroscopic change in the mobility of the liquid crystal polyester.
  • the present invention has found through research that when the DSC double enthalpy ratio ⁇ H of the liquid crystal polyester is greater than or equal to 0.1, less than or equal to 0.9, especially from 0.2 to less than or equal to 0.7, the HBA self-polymerization or molecular chain branching crosslinking is significantly weakened. It exhibits high fluidity, excellent meltability, and high molding stability of small-sized thin-walled molded articles. When ⁇ H is higher than 0.9, the processing fluidity is poor due to changes in molecular chain structure and crystallization behavior.
  • the liquid crystal polyester has a melt viscosity of 10 Pa.s-35 Pa.s, preferably 15 Pa.s-30 Pa.s, and the melt viscosity is tested by a capillary rheometer.
  • the temperature was greater than the melting point of 0-30 ° C, the shear rate was 1000 S -1 , and the die was measured using a die having an inner diameter of 1 mm and a length of 40 mm.
  • the melting point of the liquid crystal polyester should be as high as possible from the viewpoint of heat resistance, but the melting point of the liquid crystal polymer of the present invention is 310 ° C to 390 ° C in consideration of the heating ability of the molding apparatus during melt processing of the polymer. It is preferably 330 ° C to 380 ° C.
  • the melting point is measured by DSC, and the temperature is raised from the room temperature to the highest temperature of the melting point +30 ° C at a temperature rising rate of 20 ° C / min. After staying at this temperature for 3 min, the temperature is lowered to room temperature at a rate of 20 ° C / min, and the test sample is tested.
  • the temperature was raised again to the highest temperature of the melting point + 30 ° C at a heating rate of 20 ° C / min to obtain a second melting curve of the liquid crystal polyester, and the melting peak of the curve was selected as the melting point.
  • each structural unit of the present invention can be calculated by measuring 500 mg of the liquid crystal polyester or a molding composition thereof into a 25 ml volumetric flask, and adding 2.5 ml of a NaOH/CH 3 OH solution having a concentration of 5 mol/L, and then 10 ml of water-removing dimethyl sulfoxide was added. At 60 ° C, nitrogen atmosphere, thoroughly hydrolyzed and shaken for more than 18h, dissolved in water and acidified with hydrochloric acid, and then freeze-dried. An appropriate amount of the hydrolyzate was taken into an NMR (nuclear magnetic resonance) test tube, and 1H-NMR measurement was carried out, and the peak area ratio derived from each structural unit was calculated.
  • NMR nuclear magnetic resonance
  • the method for preparing the above liquid crystal polyester of the present invention comprises the following steps:
  • the pressure in the reaction vessel is reduced to 10KPa-30KPa, and acetic acid and unreacted acetic anhydride molecules are rapidly discharged from the rectification column.
  • the acetic acid receiving amount reaches 50% or more of the theoretical value, the rapid Raising to 200 ° C or above, maintaining the reduced pressure conditions and the temperature of the reaction system is programmed to the maximum temperature of the reaction, and then further reducing the pressure to 50 Kpa - 100 Kpa, melt polycondensation to obtain a prepolymer;
  • the prepolymer is cooled and solidified and granulated, and solid phase polymerization is carried out in a solid phase polymerization vessel to obtain liquid crystal polyester granules.
  • the phenolic hydroxyl group contained in the above raw material monomer is preferably acylated with a fatty acid anhydride before melt polycondensation.
  • the fatty acid anhydride is not particularly limited, and acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, 2-ethylhexanoic anhydride, dichloroacetic anhydride, dibromoacetic anhydride, difluoroacetic anhydride, maleic anhydride, and succinic anhydride can be used. Any of them may also be used in combination of two or more kinds.
  • acetic anhydride propionic anhydride or butyric anhydride is preferred, and acetic anhydride is more preferred.
  • the molar ratio of the amount of the fatty acid anhydride to the phenolic hydroxyl group used is (1 to 1.2): 1, and the amount of the fatty acid anhydride is preferably 1.02 to 1.10 equivalents from the viewpoint of producing lower degassing and soldering resistance.
  • the first stage is an acylation reaction stage, and the acylating agent acylates the phenolic hydroxyl group of the main monomer component, and the main feature of the acylation process is that nitrogen is passed through the acylation process.
  • the pressure of the reactor is maintained at 0.2 MPa to 0.6 MPa in a pressurized manner, wherein the magnitude of the holding pressure is not particularly limited, but the acylation reaction temperature must be controlled within the acylation temperature range required by the process, and the purpose is to pressurize
  • the method makes the acetic anhydride and the acetic acid product boil vigorously, and the acetic acid is generated by the self-polymerization reaction of the hydroxybenzoic acid acylate to increase the volume of the acetic acid gas, and the increase of the pressure causes the chemical reaction to proceed toward the decrease of the gas volume, so the self The poly-reaction is moderately inhibited, and the boiling acetic anhydride increases the probability of collision with the monomer, ensuring the balance of the acylation reaction of the phenolic hydroxyl group.
  • the second stage is a transesterification polymerization stage.
  • the whole reaction process is a decompression reaction, and the pressure is reduced to 10KPa-30KPa, wherein the decompression is achieved by vacuum pumping.
  • the pressure is not particularly limited, but must be programmed. Rate requirements. After the acylation is finished, the acetic acid molecules are required to be quickly discharged to meet the requirements of rapid temperature rise.
  • the acetic acid molecules Due to the nitrogen pressure in the acylation stage, the acetic acid molecules are vaporized into a large amount of mist, and then evacuated by a vacuum pump to make a large amount of acetic acid and Unreacted acetic anhydride is discharged from the reaction vessel, and the discharged acetic acid flows into the acetic acid receiving tank through the heat exchanger cooling action.
  • the heating rate is increased to make the reaction of the reaction kettle.
  • the temperature is rapidly raised to 200 ° C or higher, and a condensation reaction of an acylating group of a phenolic hydroxyl group with a carboxylic acid group is carried out to suppress self-polymerization of the monomer.
  • the pressure is reduced, and when the reaction temperature reaches the maximum temperature of the reaction, the degree of vacuum of the reactor is increased, and then further reduced to 50 Kpa-100 Kpa, so that by-products such as phenol and other small molecules are produced.
  • Continuous discharge from the reaction vessel under the action of reduced pressure reduces the probability of molecular chain rearrangement or branching, thereby reducing the branched crosslinking reaction of the molecular chain.
  • the acylation reaction is usually carried out at 100 ° C to 180 ° C for 30 minutes to 20 hours, preferably at 120 ° C to 160 ° C for 40 minutes to 5 hours.
  • the melt polycondensation can be carried out under the action of a catalyst, and the catalyst can be a conventionally known catalyst for polyester polymerization, and can be a metal salt catalyst such as potassium acetate, sodium acetate or magnesium acetate. Zinc acetate, antimony trioxide, tetrabutyl titanate and the like.
  • the melt polycondensation can be carried out under an inert gas atmosphere; the polycondensation can be carried out in a batch or continuous manner or in a combination.
  • the temperature is raised at a rate of 0.1 ° C / min to 150 ° C / min, the reactor is rapidly heated to 200 ° C or above, and enters the melt polycondensation stage; the melt polycondensation is carried out at a temperature range of 130 ° C to 400 ° C, preferably The temperature is in the range of 160 ° C to 370 ° C, wherein the highest reaction temperature is more preferably the melting point of the liquid crystal polyester + 30 ° C.
  • the polymerization vessel used for the melt polycondensation may be a polymerization vessel having a known shape.
  • a vertical polymerization tank is used, which may be a turbine blade, a twin propeller blade, a multi-stage paddle blade, preferably a turbine blade.
  • the melt viscosity of the prepolymer is preferably 10 Pa ⁇ s or less from the viewpoint of easily discharging the prepolymer in a molten state from the polymerization tank.
  • the melt viscosity was measured by a Dynisco LCR7000 capillary rheometer. The test temperature was 30 ° C above the melting point, the shear rate was 1000 S -1 , and the die was measured using a die having an inner diameter of 1 mm and a length of 40 mm.
  • the discharge of the prepolymer is preferably carried out under an inert atmosphere such as a nitrogen atmosphere, that is, by adding an inert gas to the polymerization vessel and increasing the pressure, the occurrence of side reactions can be suppressed, and the molecular weight of the prepolymer is inhibited from increasing. Large (inhibits the melt viscosity of the prepolymer).
  • the apparatus for discharging the prepolymer in a molten state may select a valve, an extruder, and a gear pump to solidify the prepolymer while continuously conveying it in one direction, and may use a wire cutter or a sheet downstream in the conveying direction.
  • the cutter or pulverizer cuts or pulverizes.
  • the prepolymer particles or powder obtained after cutting or crushing are not particularly limited, and are preferably from 0.1 mm to 5 mm.
  • acylation reaction and the transesterification polymerization may be carried out continuously in the same reactor or in different reaction vessels.
  • the solid phase polymerization is preferably carried out under a vacuum of 0.1 Pa to 50 KPa or under an inert protective gas such as nitrogen, and the polymerization temperature is about 0 to 340 ° C, and the reaction time is 0.5 to 40 hours.
  • the solid phase polymerization can be carried out in a static state with or without stirring.
  • the self-polymerization of the monomer mainly occurs under low temperature conditions, such as a temperature below 200 ° C, and the branching and crosslinking reaction of the molecular chain is mainly concentrated under high temperature conditions, such as above 300 ° C; Therefore, using the preferred preparation process to control the reaction of the two temperature segments is the key to controlling the structural arrangement of the molecular chain sequence, and is also the key to ensure that the prepared liquid crystal polyester has good processing fluidity.
  • the invention adopts the improved preparation process, effectively controls the reaction of each temperature section, and avoids the processing fluidity problem caused by monomer self-polymerization or molecular chain branching crosslinking.
  • the main feature of the adjusted polymerization process is to divide the reaction into two stages.
  • the first stage is the acylation stage of the monomer. In the acylation process, it is a pressure-holding reaction, and the pressure is maintained at 0.2 MPa-0.6 MPa; the second stage is a transesterification polymerization stage, in which the whole process of the reaction is a reduced pressure reaction, and the pressure is reduced to 10 KPa to 30 KPa.
  • the purpose of the process of combining the pressure and pressure reduction is to effectively solve the problems of a series of side reactions generated in the two reaction temperature ranges, thereby preparing a liquid crystal polyester having excellent processing fluidity and a molding composition thereof.
  • the present invention also provides a liquid crystal polyester molding composition comprising 30 parts by weight to 99.9% by weight of the liquid crystal polyester, 1 part by weight to 70 parts by weight of the reinforcing filler, and 0 to 20 parts by weight of other auxiliary agents and/or Or other polymers;
  • the liquid crystal polyester is composed of repeating structural units of the following formulas [I] to [IV]:
  • the amount of the structural unit [I] derived from p-hydroxybenzoic acid is 40 mol% or more and 80 mol% or less based on the total amount of the repeating unit 100 mol%; and the structural unit derived from 4,4'-biphenol is [II]
  • the amount is 10 mol% or more and 30 mol% or less;
  • the total amount of the structural unit [III] derived from terephthalic acid and the structural unit [IV] derived from isophthalic acid is 10 mol% or more and 32 mol% or less;
  • the ratio of the amount of the structural unit [II] to the molar total amount of the structural unit [III] and the structural unit [IV] is 1:1, wherein the structural unit derived from isophthalic acid [IV] and derived from terephthalic acid
  • the molar ratio of the structural unit [III] is preferably 0.1 to 0.49, and the sum of the molar percentages of the structural units [I], [II], [III] and [IV
  • the differential scanning calorimetry DSC test is used, and the temperature is raised from room temperature to a maximum temperature of 30 ° C/min to a temperature of +30 ° C. After staying at this temperature for 3 min, the temperature is lowered to room temperature at a rate of 20 ° C/min.
  • the crystal curve of the liquid crystal polyester is obtained, and the crystallization starting temperature and the crystallization end temperature of the crystallization peak are selected, and the crystallization peak area is calculated as H (crystalline enthalpy); the test sample is kept at room temperature for 3 min and then again at 20 ° C/min.
  • the heating rate is raised to the highest temperature of the melting point +30 ° C, and the second melting curve of the liquid crystal polyester is obtained.
  • the melting initiation temperature and the melting end temperature of the melting peak are selected, and the melting peak is calculated.
  • the area is H (melting enthalpy), and the liquid crystal polyester satisfies a double enthalpy ratio ⁇ H defined by the following formula (1) of 0.1 or more, 0.9 or less, preferably 0.2 or more and 0.7 or less;
  • ⁇ H H (melting enthalpy) / H (crystalline enthalpy).
  • the liquid crystal polyester molding composition of the present invention exhibits fluidity slightly lower than that of the resin by the influence of the filler due to the addition of various fillers, resulting in a slight increase in the double enthalpy ratio ⁇ H of the molding composition.
  • comparative test data found that when the molding composition had a double enthalpy ratio ⁇ H of less than 1.0, the processing fluidity was still superior to the liquid crystal polyester composition in the comparative test.
  • the liquid crystal polyester molding composition of the present invention is subjected to differential scanning calorimetry DSC test, and is heated from a room temperature to a maximum temperature of a melting point of +30 ° C at a heating rate of 20 ° C / min, and is kept at this temperature for 3 minutes. Further, the temperature was lowered to room temperature at a rate of 20 ° C / min to obtain a crystal curve of the liquid crystal polyester molding composition, and the crystallization starting temperature and the crystallization end temperature of the crystallization peak were selected, and the crystallization peak area was calculated as H (crystalline ⁇ ).
  • the test sample was allowed to stand at room temperature for 3 min and then heated again at a temperature increase rate of 20 ° C/min to a maximum temperature of the melting point + 30 ° C to obtain a second melting curve of the liquid crystal polyester molding composition, and the melting initiation of the melting peak was selected.
  • the temperature and the melting end temperature, and the melting peak area is calculated as H (melting enthalpy), and the liquid crystal polyester molding composition satisfies the double enthalpy ratio ⁇ H defined by the following formula (1) of 0.2 or more, less than 1.0, preferably more than Equivalent to 0.5 to less than or equal to 0.9;
  • ⁇ H H (melting enthalpy) / H (crystalline enthalpy).
  • the reinforcing filler has a fibrous shape with an average length of 0.01 mm to 20 mm, preferably 0.1 mm to 6 mm; and an aspect ratio of 5:1 to 2000:1, preferably 30:1 to 600:1.
  • the liquid crystal polyester composition exhibits not only good melt processing fluidity but also high heat distortion temperature and high rigidity.
  • the content of the reinforcing filler is preferably from 10 parts by weight to 50 parts by weight, more preferably from 15 parts by weight to 40 parts by weight;
  • the reinforcing filler is an inorganic reinforcing filler or an organic reinforcing filler.
  • the inorganic reinforcing fillers include, but are not limited to, glass fibers, potassium titanate fibers, metal clad glass fibers, ceramic fibers, wollastonite fibers, metal carbide fibers, metal curable fibers, asbestos fibers, alumina fibers, silicon carbide.
  • fibers, gypsum fibers or boron fibers preferably glass fibers.
  • the use of the glass fiber not only improves the moldability of the liquid crystal polyester composition, but also improves mechanical properties such as tensile strength, flexural strength or flexural modulus, and improves heat resistance such as heat of molding of the thermoplastic resin composition. Deformation temperature.
  • the organic reinforcing fillers include, but are not limited to, liquid crystal polyester fibers and/or carbon fibers.
  • the reinforcing filler has a non-fibrous shape and an average particle diameter of 0.001 ⁇ m to 50 ⁇ m.
  • the liquid crystal polyester resin may have poor melt processability; when the average particle diameter of the reinforcing filler is increased Greater than 50 ⁇ m will result in poor surface appearance of the injection molded article.
  • It is selected from the group consisting of potassium titanate whiskers, zinc oxide whiskers, aluminum borate whiskers, talc, carbon black, gypsum, asbestos, zeolite, sericite, kaolin, montmorillonite, clay, hectorite, synthetic mica, Aluminosilicate, silica, titania, alumina, zinc oxide, zirconium oxide, iron oxide, calcium carbonate, 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 or silicon carbide One or more of magnesium hydroxide, calcium hydroxide, aluminum hydroxide, glass beads, ceramic beads, boron nitride or silicon carbide.
  • liquid crystal polyester composition of the embodiment of the present invention it may be selected from an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a mold release agent, a dye-containing or a dye, or a range which does not impair the effects of the present invention.
  • other polymers of liquid crystal polyester or liquid crystal polyester may be blended, and the other polymer may be a wholly aromatic or semi-aromatic thermotropic liquid crystal polymer, an aromatic or semi-aromatic polyamide.
  • the method of blending the reinforcing filler, the processing aid, and the like in the liquid crystal polyester according to the embodiment of the present invention is not particularly limited, and a dry blending, a solution mixing method, or a polymerization of a liquid crystalline polyester may be used for addition, melt mixing.
  • a dry blending, a solution mixing method, or a polymerization of a liquid crystalline polyester may be used for addition, melt mixing.
  • it is preferably melt-kneaded.
  • the temperature of the melt-kneading is not less than the melting point of the liquid crystal polyester, and the melting point is +50 ° C or lower.
  • a liquid crystal polyester, a reinforcing filler, and other processing aids may be used for kneading from a post-loading machine; liquid crystal polyester and other processing may also be introduced from a post-loading machine.
  • Auxiliary agent a method of adding a reinforcing filler from a side feeder for kneading, or preparing a liquid crystal polyester composition masterbatch containing a liquid crystal polyester and other processing aid at a high concentration, and then polymerizing the mother particle and the liquid crystal
  • the ester or the reinforcing filler is a method of kneading to obtain a predetermined concentration.
  • the liquid crystal polyester composition of the embodiment of the present invention is injection-molded, and is subjected to injection molding, compression molding, extrusion molding, blow molding, press molding, and the like.
  • the molded article described herein may be various molded articles such as injection molded articles, extrusion molded articles, press molded articles, sheets, tubes, unstretched films, uniaxially stretched films, and biaxially stretched films, and may be undrawn.
  • Various kinds of filaments such as stretched silk and super drawn yarn.
  • the effects of the present invention can be remarkably obtained, and therefore it is preferable.
  • the molded article formed by the liquid crystalline polyester or liquid crystal polyester molding composition obtained by the present invention can be applied to various gears, various housings, sensors, LED lamps, connectors, sockets, resistors, relays. Housing, relay base, relay winding bobbin, switch, coil shaft, capacitor, variable capacitor housing, optical pickup, resonator, each Terminal strips, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, head mounts, power modules, housings, semiconductors, LCD components, FDD brackets, FDD chassis, HDD components Electrical and electronic components represented by motor brush holders, parabolic antennas, computer-related components, etc., VTR components, TV components, irons, hair dryers, rice cooker components, microwave oven components, audio components, audio, laser discs, optical discs, etc.
  • Households corporate electrical parts, office computer related parts, telephone related parts, fax machine related parts, copier related parts, washing, etc. represented by lighting parts, refrigerator parts, air conditioning parts, typewriter parts, word processor parts, etc.
  • bearings such as clamps, oil-free bearings, stern bearings, and underwater bearings, motor parts, mechanical parts represented by igniters, typewriters, etc., optical equipment represented by microscopes, binoculars, cameras, clocks, etc., precision Mechanical related parts Machine terminals, alternator connectors, IC regulators, potentiometer bases for dimmers, exhaust valves, various valves, fuel-related, exhaust systems, various types of suction systems, inlet nozzles , intake manifold, fuel pump, engine cooling water joint, vaporizer body, vaporizer separator, exhaust gas sensor, cooling water sensor, oil temperature sensor, throttle position sensor, crank position sensor, air flow meter, brake lining Block wear sensor, thermostat base for air conditioner, motor insulator for air conditioner, motor insulator for vehicle, electric heater
  • the invention has the following beneficial effects:
  • the present invention has found that the liquid crystal polyester of the present invention has a DSC double enthalpy ratio ⁇ H of 0.1 or more and 0.9 or less, and has a high fluidity due to its specific molecular chain structure and crystal state. It has excellent melt characteristics and high molding stability of small-sized thin-walled molded articles.
  • the invention can effectively control the acylation efficiency of the hydroxyl group by combining the polymerization process of pressurization and decompression, and effectively prevent the monomer from self-polymerization, the entanglement of the molecular chain, and the branching during the polymerization process.
  • the occurrence of side reactions such as cross-linking controls the ordered arrangement of the molecular chains of the liquid crystal polyester, and a liquid crystal polyester having a high fluidity and a molding composition thereof are prepared.
  • the preparation method of the invention is simple in operation, easy to obtain, short in production cycle, and suitable for industrial production.
  • the temperature is raised to the highest temperature of the melting point +30 ° C at a heating rate of 20 ° C / min, and the second melting curve of the polyester is obtained.
  • the melting peak of the curve is selected as the melting point, and the melting initiation temperature and melting end of the melting peak are selected.
  • the temperature and the calculated melting peak area are H (melting enthalpy), and the double enthalpy ratio ⁇ H is calculated as follows:
  • ⁇ H H (melting enthalpy) / H (crystalline enthalpy).
  • the fluidity of the liquid crystal polyester is characterized by the length of the strip-shaped sheet of the width * thickness of 5 * 0.45 mm, the injection temperature is near the melting point, and the average length of the injection molded body through 30 rod-shaped sheets
  • the fluidity of the liquid crystal polyester and its molding composition was measured as a parameter. Under the same injection molding conditions, the longer the length of the rod-shaped sheet injection molded body, the better the fluidity.
  • the following monomer raw materials, acylating agents, and catalysts were placed in a polymerization apparatus equipped with a stirrer, a reflux condenser, a monomer feed port, a nitrogen gas inlet, a thermometer, and a torque sensor.
  • the atmosphere in the reaction vessel was completely replaced with nitrogen, the temperature of the reaction system was raised to 150 ° C under a nitrogen atmosphere, and the nitrogen pressure was maintained at 0.2 MPa, and the temperature was maintained at reflux for 2 hours to carry out an acylation reaction; acylation
  • the vacuum pump is opened to reduce the pressure in the reactor to 10KPa-30KPa, and the acetic acid and unreacted acetic anhydride molecules are quickly discharged from the rectification column to meet the requirements of rapid heating process, when the acetic acid receiving amount reaches 50% of the theoretical value.
  • the temperature is rapidly raised to 200 ° C, the reduced pressure condition is maintained, and the reaction system is heated to a maximum temperature of 360 ° C in 6 hours, during which vinegar is continuously discharged.
  • Acid especially phenol or other by-product small molecules causing molecular chain re-shooting and branching, and then decompressing to 50 KPa in 30 minutes; when the stirring torque reaches a predetermined value, the reaction is considered to be completed, and the product in the reactor is taken out at this time; After cooling the product to room temperature, it was pulverized by a pulverizer, then heated from room temperature to 290 ° C in a vacuum of less than 200 Pa for 10 hours, and maintained at this temperature for 10 hours; the product obtained by the above method was observed by a polarizing microscope.
  • Example 2-5 According to the formulation of Table 1, after the acylation reaction was completed, the vacuum pump was used to decompress the pressure in the reactor to 10 KPa to 30 KPa, and the acetic acid and unreacted acetic anhydride molecules were quickly discharged from the rectification column to meet the rapid requirements.
  • the temperature rise process requires that when the acetic acid receiving amount reaches 50% or more of the theoretical value, the temperature is rapidly raised to 210 ° C, the reduced pressure condition is maintained, and the reaction system is heated to a maximum temperature of 370 ° C in 6 hours, during which the acetic acid is continuously discharged, especially A small molecule of by-product such as phenol which causes molecular chain rearrangement and branching, and then reduced to 60 KPa in 30 minutes; the rest is the same as in Example 1; the melting point, melt viscosity, double enthalpy ratio, length of the rod-shaped injection molded body of the liquid crystal polyester Listed in Table 1.
  • Example 6-12 According to the formulation of Table 1, after the acylation reaction is completed, the vacuum pump is used to decompress the pressure in the reactor to 10 KPa to 30 KPa, and the acetic acid and unreacted acetic anhydride molecules are rapidly discharged from the rectification column to meet the rapid requirements.
  • the temperature rise process requires that when the acetic acid receiving amount reaches 50% or more of the theoretical value, the temperature is rapidly raised to 220 ° C, the reduced pressure condition is maintained, and the reaction system is heated to a maximum temperature of 380 ° C in 6 hours, during which the acetic acid is continuously discharged, especially a by-product small molecule such as phenol which causes molecular chain rearrangement and branching, and then reduced to 70 KPa in 30 minutes; the rest is the same as in Example 1; the melting point, melt viscosity, storage modulus release rate of the liquid crystal polyester, rod shape
  • the fluid lengths are listed in Table 1.
  • Comparative Example 1-3 After the completion of the charging, the atmosphere in the reaction vessel was completely replaced with nitrogen, and the temperature of the reaction system was raised to 140 ° C under a nitrogen atmosphere, and the temperature was maintained at reflux for 2 hours to carry out an acylation reaction; acylation reaction After completion, the acetic acid and unreacted acetic anhydride molecules are discharged from the rectification column, and the temperature is raised and the reaction system is heated to a maximum temperature of 360 ° C in 6 hours, during which time the acetic acid is continuously discharged, and then the pressure is reduced to 30 KPa in 30 minutes; When the stirring torque reaches a predetermined value, the reaction is considered to be completed, at which time the product in the reactor is taken out; after cooling the product to room temperature, it is pulverized by a pulverizer, and then heated from room temperature to 290 in a vacuum of less than 200 Pa in 10 hours.
  • the liquid crystal polyester having a double enthalpy ratio ⁇ H of 0.1 or more and 0.9 or less the length of the rod-shaped injection molded body is significantly higher than that of the comparative example, indicating that the liquid crystal polyester in the embodiment has a high flow. Sex.
  • the liquid crystal polyester in the different double bismuth ratio ranges due to its molecular chain structure and crystal morphology.
  • the difference in the length of the rod-shaped injection molded body is that the liquid crystal polyester having different double-twist ratios exhibits different fluidity.
  • the liquid crystal polyesters of Examples 1-12 and Comparative Examples were vacuum dried at 150 ° C for 12 hours or more, and then the resin and the auxiliary agent were supplied from the main feed port of the twin-screw extruder by a high-speed mixer.

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Abstract

本发明公开了一种液晶聚酯以及由其组成的模塑组合物和其应用，由式[Ⅰ]-[Ⅳ]的重复结构单元构成；其中采用差示扫描量热DSC测试，该液晶聚酯满足由下式(1)定义的双焓比ΔH大于等于0.1，小于等于0.9，优选大于等于0.2至小于等于0.7。 (1)ΔH＝H(熔融焓)/H(结晶焓)。本发明的液晶聚酯的DSC双焓比ΔH大于等于0.1，小于等于0.9，该液晶聚酯以及由该液晶聚酯制备的模塑组合物具有较高的流动性，熔融特性优异，小型薄壁成型品的成型稳定性高，特别适合应用于薄壁电子制件中。

Description

一种液晶聚酯以及由其组成的模塑组合物和其应用 技术领域
本发明涉及高分子材料领域，特别涉及一种液晶聚酯以及由其组成的模塑组合物和其应用。
背景技术
热致性液晶聚合物(TLCP)作为一种高性能特种工程塑料，具有优良的机械性能，良好的流动性，耐热性，耐化学腐蚀，阻燃及电绝缘性能，目前在电子电器及小型精密薄壁零部件等领域应用广泛。其制备通常采用的是高温熔融聚合法，但由于HBA等单体的自聚或分子链的支化交联反应，导致最终的液晶产品的熔融加工性及物理性能较差，特别是树脂的流动性受到严重影响，导致液晶聚酯模塑组合物在成型过程中出现模具填充不满等情况，严重影响了液晶聚合物在电子电器薄壁制件中的应用。
对于抑制HBA的自聚，及在高温聚合过程中控制交联等副反应发生的研究一直是科研和工业中的重大课题，如专利CN1673249A，CN104004170 A，CN104098760A，CN104098761A中提到通过加入4-甲基苯磺酸，水，或醋酸的方法抑制脱羧反应及HBA的自聚反应等，上述方法对液晶聚合物的特性粘度有一定的改善作用。
如上述专利，目前液晶聚酯的特性粘度已经成为本行业一个通用的手段，用以表征液晶聚酯的相对分子质量及分子链运动特性，间接反应了最终液晶聚酯的流动性。然而特性粘度的不同并不是影响聚合物流动性的唯一因素。原料单体结构或比例的不同，单体自聚程度的大小，分子量和分子链序列结构的变化，分子链段是否均匀，分子链的缠结或支化程度的高低，分子链的运动能力和结晶结构及速度的快慢，制备工艺过程等都会对聚合物的流动性产生影响。
差示扫描量热分析(DSC)是最常用的热分析仪器之一，用于表征聚合物熔融结晶过程，反应了分子链结构与结晶之间的关系，分子链结构的变化，直接决定了DSC在升温或降温的过程中熔融或结晶行为。本申请人不断研究进一步发现具有特定熔融结晶焓比值即双焓比范围内的液晶聚酯，由于具有特定的分子链的结构及结晶状态，因此展现出优良的加工流动性和机械性能。
发明内容
本发明的首要目的在于提供一种高流动性的液晶聚酯，该液晶聚酯的双焓比ΔH在特定范围内，具有明显改善的加工流动性。
本发明另一目的在于提供一种包含上述液晶聚酯的模塑组合物。
本发明是通过以下技术方案实现的：
一种液晶聚酯，由下式[Ⅰ]-[Ⅳ]的重复结构单元构成：
Figure PCTCN2017071467-appb-000001
以重复单元总量100mol％计，衍生自对羟基苯甲酸的结构单元[Ⅰ]的量大于等于40mol％，小于等于80mol％；衍生自4,4’-联苯二酚的结构单元[Ⅱ]的量大于等于10mol％，小于等于30mol％；衍生自对苯二甲酸的结构单元[Ⅲ]和衍生自间苯二甲酸的结构单元[Ⅳ]的总量大于等于10mol％，小于等于32mol％；结构单元[Ⅱ]的量与结构单元[Ⅲ]和结构单元[Ⅳ]的摩尔总量之比为1:1，其中衍生自间苯二甲酸的结构单元[Ⅳ]和衍生自对苯二甲酸的结构单元[Ⅲ]的摩尔比优选0.1至0.49，结构单元[Ⅰ]、[Ⅱ]、[Ⅲ]和[Ⅳ]的摩尔百分数总和为100％；
其中采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，该液晶聚酯满足由下式(1)定义的双焓比ΔH大于等于0.1，小于等于0.9，优选大于等于0.2至小于等于0.7；
(1)ΔH＝H(熔融焓)/H(结晶焓)。
DSC双焓比ΔH是液晶聚酯晶体熔融焓与结晶焓的比值，其实际反应的物理意义即是液晶聚酯晶体结构破坏和分子链结晶的难易程度与液晶聚酯分子链结构的关系。结晶行为与 晶体熔融行为和分子链的结构特征具有密切联系，对于理想的分子链间无相互作用，分子链结构规整，内旋转能力大，柔顺性高，此时的分子链的运动没有摩擦等阻力，分子链运动自由，表现出完美的流动性，因此分子链结晶能力高，结晶结构堆砌致密规整。但实际合成液晶聚酯由于原料单体结构或比例的不同，单体自聚程度的大小，分子量和分子链序列结构的变化，分子链段是否均匀及分子链是否规整，分子链的缠结或支化程度的高低，分子链内旋转能力的高低，分子链的运动能力，制备工艺过程等诸多因素的影响，从而影响了最终制备得到的液晶聚酯的分子链结构存在较大区别，其分子链排列结晶行为和晶体结构的破坏行为发生较大变化，表现在DSC的熔融焓和结晶焓变中具有一定波动性，而这种焓变的波动正是反应了分子链的结构特征，以及由其导致的液晶聚酯宏观的流动性变化。
本发明通过研究发现，当液晶聚酯的DSC双焓比ΔH大于等于0.1，小于等于0.9，尤其是在大于等于0.2至小于等于0.7，HBA自聚链段或分子链支化交联明显减弱，表现出较高的流动性，熔融特性优异，小型薄壁成型品的成型稳定性高，当ΔH高于0.9时，则由于分子链结构及结晶行为的变化，导致其加工流动性较差。
为了完成本发明的制备一种高流动性液晶聚酯，液晶聚酯的熔融黏度为10Pa.s-35Pa.s，优选为15Pa.s-30Pa.s，熔融黏度采用毛细管流变仪测试，测试温度为大于熔点0-30℃，剪切速率1000S-1，使用内径1mm，长度40mm的口模测量。
从耐热性的观点考虑，液晶聚酯的熔点应尽可能的高，但考虑到聚合物熔融加工时成型设备的加热能力，本发明所述的液晶聚合物的熔点为310℃-390℃，优选为330℃-380℃。熔点采用DSC测得，从室温起以20℃/min的升温速率条件下升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降温至室温，测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取此曲线熔融峰值即为熔点。
本发明各结构单元的含量可以通过如下方法计算得出：将500mg液晶聚酯或其模塑组合物量取至25ml容量瓶中，加入2.5ml浓度为5mol/L的NaOH/CH3OH溶液，再加入10ml除水二甲基亚砜。在60℃的温度下，氮气氛围，彻底水解摇匀18h以上，加水溶解并用盐酸酸化后冷冻干燥。取适量水解产物至NMR(核磁共振)试管中，进行1H-NMR测定，有来源于各结构单元的峰面积比计算得到。
本发明上述液晶聚酯的制备方法，包括如下步骤：
a、在氮气加压条件下，以对羟基苯甲酸、4,4’-联苯二酚、对苯二甲酸和间苯二甲酸为原料，在酰化剂的作用下进行酰化反应，所述压力保持在0.2MPa-0.6MPa；
b、酰化反应结束后，将反应釜内压力进行减压至10KPa-30KPa，从精馏柱迅速排出醋酸及未反应的醋酸酐分子，当醋酸接收量到达理论值的50％以上时，快速升温至200℃或以上，保持此减压条件并将反应体系程序升温到反应最高温度，然后进一步减压至50Kpa-100Kpa，熔融缩聚得到预聚物；
c、将预聚物冷却固化并造粒，在固相聚合容器中进行固相聚合得到液晶聚酯颗粒。
上述原料单体中所含有的酚羟基优选在熔融缩聚前用脂肪酸酐酰化。对于脂肪酸酐没有特别限定，可使用乙酸酐、丙酸酐、丁酸酐、戊酸酐、2-乙基己酸酐、二氯乙酸酐、二溴乙酸酐、二氟乙酸酐、马来酸酐和琥珀酸酐中的任一种，也可以以两种或多种混合物使用。从生产成本角度考虑，优选乙酸酐、丙酸酐或丁酸酐，更优选乙酸酐。所用脂肪酸酐的量与酚羟基的摩尔比为(1～1.2):1，从产生较低脱气和耐焊接起泡性角度考虑，脂肪酸酐的用量优选1.02～1.10倍当量。
上述所述的液晶聚酯的制备方法，第一阶段为酰化反应阶段，酰化剂将主要单体成分的酚羟基进行酰化反应，酰化工艺主要特点是，在酰化过程中通过氮气加压的方式将反应釜的压力保持在0.2MPa-0.6MPa，其中保持压力的大小无特定限制，但必须将酰化反应温度控制在工艺要求的酰化温度范围内，其目的是通过加压的方式使醋酸酐及醋酸产物剧烈沸腾，由于对羟基苯甲酸酰化物的自聚反应产生醋酸，增大醋酸气体体积，而压强增大引起化学反应向着气体体积减小的方向进行，因此该自聚反应被适度抑制，同时沸腾的醋酸酐增加了与单体碰撞的几率，保证了酚羟基的酰化反应的平衡。第二阶段为酯交换聚合阶段，此阶段整个反应过程为减压反应，抽真空减压至10KPa-30KPa，其中减压通过真空泵抽气实现，其压力的大小无特别限制，但必须满足程序升温速率的要求。在酰基化结束后，要求醋酸分子要迅速排出，以满足快速升温的要求，由于酰化阶段的氮气加压，使得醋酸分子大量气化成雾，后经真空泵抽气减压，使得大量的醋酸及未反应的醋酸酐从反应釜排出，排出的醋酸经换热器冷却作用流入醋酸接收罐中，当醋酸接收量到达理论值的50％以上时，此时加大升温速率，使反应釜的反应温度迅速升温至200℃或以上，进入酚羟基的酰化基团与羧酸基团的缩合反应，以抑制单体的自聚。在酯交换聚合阶段，采用减压的方式，且当反应温度到达反应最高温度后，增大反应釜的真空度，然后进一步减压至50Kpa-100Kpa，使得反应产生的副产物如苯酚等小分子在减压的作用下从反应釜中持续排出，减少分子链重排或支化的几率，从而降低分子链的支化交联反应。酰化反应通常在100℃～180℃反应30分钟～20小时，优选可在120℃～160℃反应40分钟～5小时。所述的熔融缩聚可在催化剂的作用下进行，催化剂采用常规已知的聚酯聚合用催化剂，可以是金属盐类催化剂，如醋酸钾，醋酸钠，醋酸镁， 醋酸锌，三氧化二锑，钛酸四丁酯等。
所述的熔融缩聚可在惰性气体气氛下进行；缩聚可以在间歇或连续方式或组合方式进行。酰化反应结束后，以0.1℃/min～150℃/min的速率升温，使反应釜快速升温到200℃或以上，进入熔融缩聚阶段；熔融缩聚在130℃～400℃温度范围下进行，优选在160℃～370℃温度范围下进行，其中最高反应温度更优选为液晶聚酯的熔点+30℃的温度。
所述的熔融缩聚所使用的聚合容器可以是具有已知形状的聚合容器。优选使用立式聚合罐，搅拌桨可以为涡轮桨叶、双螺旋桨叶、多级桨式桨叶，优选为涡轮桨叶。
所述的熔融缩聚后，出于容易将熔融状态的预聚物从聚合罐中排出的观点考虑，预聚物的熔融黏度优选在10Pa·s以下。熔融黏度采用Dynisco LCR7000型毛细管流变仪测试，测试温度为大于熔点30℃，剪切速率1000S-1，使用内径1mm，长度40mm的口模测量。
所述的熔融缩聚后，预聚物的排出优选在惰性气氛如氮气气氛下进行，即向聚合容器中加入惰性气体并增大压力，可以抑制副反应的发生，同时抑制预聚物分子量的增大(抑制预聚物的熔融黏度)。在熔融状态下排出预聚物的设备可选择阀门、挤出机和齿轮泵，固化所述预聚物，同时以一个方向对其进行连续传送，在传送方向下游可利用线材切割机、片材切割机或粉碎机进行切割或粉碎。切割或破碎后得到的预聚物颗粒或粉末并无特别限制，优选在0.1mm～5mm。
另外，酰化反应与酯交换聚合可以在同一反应器中连续进行，也可以在不同反应容器中进行。
所述的固相聚合优选在真空度0.1Pa～50KPa，或者通氮气等惰性保护气体条件下进行，聚合温度约0～340℃，反应时间0.5小时～40小时。固相聚合可在搅拌或无搅拌的静止状态下进行。
根据本发明的大量实验数据表明，单体自聚主要发生在低温条件下，如200℃以下的温度，而分子链的支化交联等反应则主要集中在高温条件下，如300℃以上；因此采用优选的制备工艺，控制好此两个温度段的反应，是控制分子链序列结构排列的关键，也是保证制备的液晶聚酯具有较好加工流动性的关键。本发明采用改进后的制备工艺，有效控制了各温度段的反应，避免了由于单体自聚或分子链支化交联所导致的加工流动性问题。且对实验数据整理发现，采用本发明工艺制备的液晶聚酯及其模塑组合物经DSC对结晶焓和熔融焓的测试，当双焓比ΔH处在一个优选范围，都表现出较高的流动性，但当双焓比ΔH高于本发明的优选范围时，则由于分子量结构和结晶结构的变化，加工流动性变差。
调整后的聚合工艺主要特点是将反应分为两个阶段，第一阶段即单体的酰化阶段， 在酰化过程中为加压保压反应，其压力保持在0.2MPa-0.6MPa；第二阶段为酯交换聚合阶段，此阶段反应整个过程为减压反应，抽真空减压至10KPa-30KPa。采用此加压减压相结合的工艺的目的就是要有效解决好两个反应温度段产生的一系列副反应的问题，从而制备出具有优良加工流动性的液晶聚酯及其模塑组合物。
本发明还提供了一种液晶聚酯模塑组合物，包括30重量份-99.9重量份的液晶聚酯、1重量份-70重量份的增强填料和0-20重量份的其他助剂和/或其他聚合物；其中，
所述液晶聚酯由下式[Ⅰ]-[Ⅳ]的重复结构单元构成：
Figure PCTCN2017071467-appb-000002
以重复单元总量100mol％计，衍生自对羟基苯甲酸的结构单元[Ⅰ]的量大于等于40mol％，小于等于80mol％；衍生自4,4’-联苯二酚的结构单元[Ⅱ]的量大于等于10mol％，小于等于30mol％；衍生自对苯二甲酸的结构单元[Ⅲ]和衍生自间苯二甲酸的结构单元[Ⅳ]的总量大于等于10mol％，小于等于32mol％；结构单元[Ⅱ]的量与结构单元[Ⅲ]和结构单元[Ⅳ]的摩尔总量之比为1:1，其中衍生自间苯二甲酸的结构单元[Ⅳ]和衍生自对苯二甲酸的结构单元[Ⅲ]的摩尔比优选0.1至0.49，结构单元[Ⅰ]、[Ⅱ]、[Ⅲ]和[Ⅳ]的摩尔百分数总和为100％；
其中采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰 面积即为H(熔融焓)，该液晶聚酯满足由下式(1)定义的双焓比ΔH大于等于0.1，小于等于0.9，优选大于等于0.2至小于等于0.7；
(1)ΔH＝H(熔融焓)/H(结晶焓)。
本发明所述的液晶聚酯模塑组合物由于加入各种填料，其流动性亦受到填料的影响表现出略低于树脂的流动性，导致模塑组合物的双焓比ΔH会稍微提高，但对比试验数据发现，当模塑组合物的双焓比ΔH小于1.0时，其加工流动性仍优于对比试验中的液晶聚酯组合物。
本发明所述的液晶聚酯模塑组合物，采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯模塑组合物的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯模塑组合物的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，该液晶聚酯模塑组合物满足由下式(1)定义的双焓比ΔH大于等于0.2，小于1.0，优选大于等于0.5至小于等于0.9；
(1)ΔH＝H(熔融焓)/H(结晶焓)。
其中，所述增强填料的形状为纤维状，其平均长度为0.01mm-20mm，优选为0.1mm～6mm；其长径比为5:1～2000:1，优选为30:1～600:1；当所选纤维状增强填料尺寸在上述范围内时，液晶聚酯组合物不但表现较好的熔融加工流动性，而且表现出高热变形温度和高刚性。
增强填料含量过低，导致液晶聚酯模塑组合物力学性能较差；增强填料含量过高，液晶聚酯模塑组合物制品表面浮纤严重，影响产品外观。所述增强填料的含量优选为10重量份-50重量份，更优选为15重量份-40重量份；
所述增强填料为无机增强填料或有机增强填料。
所述无机增强填料包括但不仅限于玻璃纤维、钛酸钾纤维、金属包层的玻璃纤维、陶瓷纤维、硅灰石纤维、金属碳化物纤维、金属固化纤维、石棉纤维、氧化铝纤维、碳化硅纤维、石膏纤维或硼纤维的一种或几种，优选为玻璃纤维。使用玻璃纤维不仅可提高液晶聚酯组合物的可模塑性，而且可提高力学性能例如拉伸强度，弯曲强度或弯曲模量，及提高耐热性例如热塑性树脂组合物进行模塑是的热变形温度。
所述有机增强填料包括但不仅限于液晶聚酯纤维和/或碳纤维。
所述增强填料的形状为非纤维状，其平均粒径为0.001μm-50μm，当增强填料的平均粒径小于0.001μm将导致液晶聚酯树脂差的熔融加工性；当增强填料的平均粒径大于50μm，将导致不良的注塑成型品表面外观。其选自钛酸钾晶须、氧化锌晶须、硼酸铝晶须、滑石粉、炭黑、石膏、石棉、沸石、绢云母、高岭土、蒙脱土、粘土、锂蒙脱土、合成云母、硅铝酸盐、二氧化硅、氧化钛、氧化铝、氧化锌、氧化锆、氧化铁、碳酸钙、钛酸镁、白云石、硫酸铝、硫酸钡、硫酸镁、碳酸钙、云母、石英粉、氢氧化镁、氢氧化钙、氢氧化铝、玻璃珠、陶瓷珠、氮化硼或碳化硅的一种或几种。
本发明的实施方式的液晶聚酯组合物中，在不损坏本发明的效果的范围内，还可以配合选自抗氧化剂、热稳定剂、紫外线吸收剂、润滑剂、脱模剂、包含染料或颜料的着色剂、增塑剂、抗静电剂中的通常的加工助剂。或可以配合其他结构的液晶性聚酯或液晶聚酯以外的聚合物，所述的其他聚合物可以为全芳香族或半芳香族热致性液晶聚合物，芳香族或半芳香族聚酰胺，聚醚醚酮，聚醚砜，聚烯烃均聚物或共聚物等的一种或几种。通过这样的配合，可以进一步赋予规定的特性。
作为在本发明的实施方式的液晶聚酯中配合增强填料、加工助剂等的方法，没有特定的限定，可以使用干式掺混、溶液混合法、液晶性聚酯的聚合是添加、熔融混炼等，其中优选为熔融混炼。如捏合机，单轴或双轴挤出机、胶辊机等，其中优选使用双轴挤出机。熔融混炼的温度为液晶聚酯的熔点以上，熔点+50℃以下。
作为混炼方法，可以使用从后装进料机一并投入液晶聚酯、增强填料、其他加工助剂来进行混炼的方法；也可以从后装进料机透入液晶聚酯和其他加工助剂剂，从侧进料机添加增强填料进行混炼的方法，亦可以制备高浓度包含液晶性聚酯和其他加工助剂的液晶性聚酯组合物母粒，接着将母粒与液晶聚酯，增强填料进行混炼以成为规定的浓度的方法等的任一种方法。
本发明的实施方式的液晶聚酯组合物通过进行注射成型，注射压缩成型、压缩成型、挤出成型、吹塑成型、压制成型纺丝等公知的熔融成型品。这里所述的成型品，可以为注射成型品、挤出成型品、压制成型品、片、管、未拉伸薄膜、单轴拉伸薄膜、双轴拉伸薄膜等各种膜制品、未拉伸丝、超拉伸丝等各种纤维丝等。在注射成型的情况下，可显著获得本发明的效果，因此优选。
本发明所获得的液晶性聚酯或液晶聚酯模塑组合物形成的成型品可以有如下应用，以各种齿轮、各种壳体、传感器、LED灯、连接器、插座、电阻器、继电器壳体、继电器底座、继电器用绕线轴、开关、线圈轴、电容器、可变电容器壳体、光拾波器、共振器、各 种端子板、变压器、插头、印刷布线板、调谐器、扬声器、传声器、头戴式听筒、小型电动机、磁头底座、功率模块、外壳、半导体、液晶显示器部件、FDD托架、FDD底盘、HDD部件、电动机刷握、抛物面天线、计算机相关部件等为代表的电气电子部件、以VTR部件、电视部件、熨斗、电吹风、电饭煲部件、微波炉部件、音响部件、音频、激光盘、光盘等语音设备部件、照明部件、电冰箱部件、空调部件、打字机部件、文字处理机部件等为代表的家庭、企业电气制品部件、办公室计算机相关部件、电话机相关部件、传真机相关部件、复印机相关部件、洗涤用夹具、无油轴承、船尾轴承、水中轴承等各种轴承、电动机部件、以点火器、打字机等为代表的机械相关部件、以显微镜、双筒望远镜、照相机、钟表等为代表的光学设备、精密机械相关部件；交流发电机端子、交流发电机连接器、IC调节器、调光器用电位器底座、排气气阀等各种阀、燃料关联、排气系、吸气系的各种管、进气口喷嘴通气管、进气歧管、燃料泵、发动机冷却水接头、汽化器主体、汽化器隔离物、排气气体传感器、冷却水传感器、油温传感器、节气门位置传感器、曲轴位置传感器、空气流量计、制动衬块磨耗传感器、空调用恒温器底座、空调用电动机绝缘体、电动窗等车载用电动机绝缘体、取暖器暖风流量控制阀、散热器电动机用刷握、水泵叶轮、涡轮叶片、刮水器电动机相关部件、分电器、起动器开关、起动器继电器、传动装置用线束、窗户洗涤器喷嘴、空调面板开关基板、燃料关联电磁阀用线圈、保险丝用连接器、喇叭端子、电装部件绝缘板、步进电动机转子、灯圈、灯座、灯光反射器、灯壳、制动活塞、螺线管线轴、发动机滤油器、点火装置壳体等汽车、车辆相关部件等，在印刷布线板，小型薄壁电子器件等中特别有用。
本发明与现有技术相比，具有如下有益效果：
(1)本发明通过研究发现，本发明的液晶聚酯的DSC双焓比ΔH大于等于0.1，小于等于0.9，由于其具有特定的分子链的结构及结晶状态，因此具有较高的流动性，熔融特性优异，小型薄壁成型品的成型稳定性高。
(2)本发明在整个合成过程中，结合加压和减压的聚合工艺，能够有效控制羟基的酰化效率，并在聚合的过程有效阻止单体自聚，分子链的缠结，支化交联等副反应的发生，控制了液晶聚酯的分子链的有序排列，制备得到具有较高的流动性的液晶聚酯及其模塑组合物。
(3)本发明的制备方法操作简单，产品易于获得，生产周期较短，适于工业化生产。
具体实施方式
本发明实施例所采用的各原料、酰化剂、催化剂、玻璃纤维、云母和硬脂酸钙等其他助剂均来源于市购。
本发明中必要的性能表征及其测试方法：
(1)熔点及熔融焓、结晶焓测试：采用NETZSCH公司制DSC 200 F3测得，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降温至室温，得到结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到聚酯的第二次熔融曲线，选取此曲线熔融峰值即为熔点，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，双焓比ΔH按下式计算：
ΔH＝H(熔融焓)/H(结晶焓)。
(2)流动性：采用尺寸为宽*厚为5*0.45mm的棒状薄片注塑体的长度来表征液晶聚酯的流动性，注塑温度在熔点附近，通过30根棒状薄片注塑体的长度平均值作为参数衡量液晶聚酯及其模塑组合物的流动性。在注塑条件相同的条件下，棒状薄片注塑体长度越长，表明其流动性越好。
(3)熔融粘度：采用DyniscoLCR7001型毛细管流变仪进行测试，口模直径为1mm，长度为40mm，所述液晶聚酯在其熔融温度以上20℃，剪切速率为1000s-1条件下的粘度为熔融粘度。
实施例1
向装有搅拌器、回流冷凝器、单体投料口、氮气导入口、温度计和扭矩传感器的聚合反应装置中，加入以下单体原料、酰化剂、催化剂。
(Ⅰ)对羟基苯甲酸1180克(60mol％)HBA
(Ⅱ)4,4’-联苯二酚530.1克(20mol％)BP
(Ⅲ)对苯二甲酸402.1克(17mol％)TA
(Ⅳ)间苯二甲酸70.9克(3mol％)IA
酰化剂：乙酸酐1527克
催化剂：醋酸镁115毫克
投料完成后，用氮气彻底置换反应容器内的气氛，通氮气保护下将反应体系的温度升高至150℃，并保持氮气压力为0.2MPa，维持此温度回流2小时进行酰化反应；酰化反应结束后，开真空泵将反应釜内压力减压到10KPa-30KPa，从精馏柱迅速排出醋酸及未反应的醋酸酐分子，以满足迅速升温的工艺要求，当醋酸接收量到达理论值的50％以上时，迅速升温至200℃，保持此减压条件并将反应体系在6小时内升温至最高温度360℃，期间持续排出醋 酸特别是苯酚等引起分子链重拍及支化的副产物小分子，然后在30分钟内减压至50KPa；当搅拌扭矩达到预定值后，认为反应结束，此时取出反应器内的产物；将产物冷却至室温后，用粉碎机粉碎，然后在在真空度小于200Pa下在10小时内由室温加热至290℃，并在此温度下维持10小时；通过偏光显微镜观察上述方法所得到的产物，发现其为可在熔融态显示光学各向异性的液晶聚合物。该液晶聚酯的熔融温度，熔融粘度，储能模量释放率，棒状注塑体长度，列于表1中。
实施例2-5：按照表1的配方，酰化反应结束后，开真空泵将反应釜内压力减压到10KPa-30KPa，从精馏柱迅速排出醋酸及未反应的醋酸酐分子，以满足迅速升温的工艺要求，当醋酸接收量到达理论值的50％以上时，迅速升温至210℃，保持此减压条件并将反应体系在6小时内升温至最高温度370℃，期间持续排出醋酸特别是苯酚等引起分子链重排及支化的副产物小分子，然后在30分钟内减压至60KPa；其余同实施例1；该液晶聚酯的熔点，熔融粘度，双焓比，棒状注塑体长度列于表1中。
实施例6-12：按照表1的配方，酰化反应结束后，开真空泵将反应釜内压力减压到10KPa-30KPa，从精馏柱迅速排出醋酸及未反应的醋酸酐分子，以满足迅速升温的工艺要求，当醋酸接收量到达理论值的50％以上时，迅速升温至220℃，保持此减压条件并将反应体系在6小时内升温至最高温度380℃，期间持续排出醋酸特别是苯酚等引起分子链重排及支化的副产物小分子，然后在30分钟内减压至70KPa；其余同实施例1；该液晶聚酯的熔点，熔融粘度，储能模量释放率，棒状流体长度列于表1中。
对比实施例1-3：投料完成后，用氮气彻底置换反应容器内的气氛，通氮气保护下将反应体系的温度升高至140℃，维持此温度回流2小时进行酰化反应；酰化反应结束后，从精馏柱一边排出醋酸及未反应的醋酸酐分子，一边升温并将反应体系在6小时内升温至最高温度360℃，期间持续排出醋酸，然后在30分钟内减压至30KPa；当搅拌扭矩达到预定值后，认为反应结束，此时取出反应器内的产物；将产物冷却至室温后，用粉碎机粉碎，然后在在真空度小于200Pa下在10小时内由室温加热至290℃，并在此温度下维持10小时；通过偏光显微镜观察上述方法所得到的产物，发现其为可在熔融态显示光学各向异性的液晶聚合物。该液晶聚酯的熔点，熔融粘度，双焓比，棒状注塑体长度，列于表1中。
表1
Figure PCTCN2017071467-appb-000003
由上述结果可以看出，实施例中双焓比ΔH大于等于0.1，小于等于0.9范围内的液晶聚酯，棒状注塑体长度明显高于对比例，说明实施例中的液晶聚酯具有高的流动性。
另外，从实施例和对比例也可以看出，即使在原料单体结构、比例相同，熔融粘度相似的条件下，不同双焓比范围内的液晶聚酯，由于其其分子链结构及结晶形态的不同，棒状注塑体长度具有明显差异，即具有不同双焓比的液晶聚酯会表现出不同的流动性。
实施例13-24、对比例4-7：液晶聚酯模塑组合物的制备
按表2的配比将由实施例1-12及对比例的液晶聚酯，在150℃进行12h以上的真空干燥后，利用高速混合机将树脂及助剂从双螺杆挤出机主喂料口加入到挤出机中，按照比例将玻璃纤维及云母，硬脂酸钙等其他助剂从双螺杆挤出机侧喂料口加入到挤出机中，经熔融混合，选择合适的螺筒温度挤出，造粒，在足够长的空气流的环状冷却风冷却固化，得到液晶聚酯组合物；分别测试液晶聚酯组合物的熔点，熔融粘度，双焓比，棒状注塑体长度测试结果列于表2中。
表2
Figure PCTCN2017071467-appb-000004
由表2的结果可以看出，由于采用了双焓比ΔH大于等于0.1，小于等于0.9的液晶聚酯树脂，其分子链结构及结晶形态发生了较大变化，实施例液晶聚酯模塑组合物的流动性明显较对比例高，特别适合应用于薄壁电子制件中。

Claims (15)

  1. 一种液晶聚酯，由下式[Ⅰ]-[Ⅳ]的重复结构单元构成：
    Figure PCTCN2017071467-appb-100001
    以重复单元总量100mol％计，衍生自对羟基苯甲酸的结构单元[Ⅰ]的量大于等于40mol％，小于等于80mol％；衍生自4,4’-联苯二酚的结构单元[Ⅱ]的量大于等于10mol％，小于等于30mol％；衍生自对苯二甲酸的结构单元[Ⅲ]和衍生自间苯二甲酸的结构单元[Ⅳ]的总量大于等于10mol％，小于等于32mol％；结构单元[Ⅱ]的量与结构单元[Ⅲ]和结构单元[Ⅳ]的摩尔总量之比为1:1，其中衍生自间苯二甲酸的结构单元[Ⅳ]和衍生自对苯二甲酸的结构单元[Ⅲ]的摩尔比优选0.1至0.49，结构单元[Ⅰ]、[Ⅱ]、[Ⅲ]和[Ⅳ]的摩尔百分数总和为100％；
    其中采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，该液晶聚酯满足由下式(1)定义的双焓比ΔH大于等于0.1，小于等于0.9，优选大于等于0.2至小于等于0.7；
    (1)ΔH＝H(熔融焓)/H(结晶焓)。
  2. 根据权利要求1所述的液晶聚酯，其特征在于，所述液晶聚酯的熔融黏度为10Pa.s-35Pa.s，优选为15Pa.s-30Pa.s，熔融黏度采用毛细管流变仪测试，测试温度为大于熔点0-30℃，剪切速率1000S-1，使用内径1mm，长度40mm的口模测量。
  3. 根据权利要求1所述的液晶聚酯，其特征在于：所述液晶聚酯的熔点为310℃-390℃，优选为330℃-380℃，熔点采用DSC测得，从室温起以20℃/min的升温速率条件下升温到熔 点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降温至室温，测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取此曲线熔融峰值即为熔点。
  4. 根据权利要求1-3任一项所述的液晶聚酯的制备方法，其特征在于，包括如下步骤：
    a、在氮气加压条件下，以对羟基苯甲酸、4,4’-联苯二酚、对苯二甲酸和间苯二甲酸为原料，在酰化剂的作用下进行酰化反应，所述压力保持在0.2MPa-0.6MPa；
    b、酰化反应结束后，将反应釜内压力进行减压至10KPa-30KPa，从精馏柱迅速排出醋酸及未反应的醋酸酐分子，当醋酸接收量到达理论值的50％以上时，快速升温至200℃或以上，保持此减压条件并将反应体系程序升温到反应最高温度，然后进一步减压至50Kpa-100Kpa，熔融缩聚得到预聚物；
    c、将预聚物冷却固化并造粒，在固相聚合容器中进行固相聚合得到液晶聚酯颗粒。
  5. 根据权利要求4所述的液晶聚酯的制备方法，其特征在于，步骤a中，所述酰化反应的温度为100℃～180℃，优选120℃～160℃，反应时间为30分钟～20小时，优选40分钟～5小时。
  6. 根据权利要求4所述的液晶聚酯的制备方法，其特征在于，步骤b中，酰化反应结束后，以0.1℃/min～150℃/min的速率升温，使反应釜快速升温到200℃或以上，进入熔融缩聚阶段，所述熔融缩聚的温度为130℃～400℃，优选160℃～370℃。
  7. 根据权利要求4所述的液晶聚酯的制备方法，其特征在于，步骤c中，所述固相聚合在真空度0.1Pa～50KPa，或者通氮气等惰性保护气体条件下进行，聚合温度为0～340℃，反应时间为0.5小时～40小时。
  8. 一种包含权利要求1-3任一项所述的液晶聚酯的液晶聚酯模塑组合物，包括30重量份-99.9重量份的液晶聚酯、1重量份-70重量份的增强填料和0-20重量份的其他助剂和/或其他聚合物；其中，
    所述液晶聚酯由下式[Ⅰ]-[Ⅳ]的重复结构单元构成：
    Figure PCTCN2017071467-appb-100002
    以重复单元总量100mol％计，衍生自对羟基苯甲酸的结构单元[Ⅰ]的量大于等于40mol％，小于等于80mol％；衍生自4,4’-联苯二酚的结构单元[Ⅱ]的量大于等于10mol％，小于等于30mol％；衍生自对苯二甲酸的结构单元[Ⅲ]和衍生自间苯二甲酸的结构单元[Ⅳ]的总量大于等于10mol％，小于等于32mol％；结构单元[Ⅱ]的量与结构单元[Ⅲ]和结构单元[Ⅳ]的摩尔总量之比为1:1，其中衍生自间苯二甲酸的结构单元[Ⅳ]和衍生自对苯二甲酸的结构单元[Ⅲ]的摩尔比优选0.1至0.49，结构单元[Ⅰ]、[Ⅱ]、[Ⅲ]和[Ⅳ]的摩尔百分数总和为100％；
    其中采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，该液晶聚酯满足由下式(1)定义的双焓比大于等于0.1，小于等于0.9，优选大于等于0.2至小于等于0.7；
    (1)ΔH＝H(熔融焓)/H(结晶焓)。
  9. 根据权利要求8所述的液晶聚酯模塑组合物，其特征在于，所述液晶聚酯的熔融黏度为10Pa.s-35Pa.s，优选为15Pa.s-30Pa.s，熔融黏度采用毛细管流变仪测试，测试温度为大于熔点0-30℃，剪切速率1000S-1，使用内径1mm，长度40mm的口模测量。
  10. 根据权利要求8所述的液晶聚酯模塑组合物，其特征在于：所述液晶聚酯的熔点为310℃-390℃，优选为330℃-380℃，熔点采用DSC测得，从室温起以20℃/min的升温速率条件 下升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降温至室温，测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯的第二次熔融曲线，选取此曲线熔融峰值即为熔点。
  11. 根据权利要求8所述的液晶聚酯模塑组合物，其特征在于，所述增强填料的形状为纤维状，其平均长度为0.01mm-20mm，优选为0.1mm～6mm；其长径比为5:1～2000:1，优选为30:1～600:1；所述增强填料的含量优选为10重量份-50重量份，更优选为15重量份-40重量份；所述增强填料为无机增强填料或有机增强填料，所述无机增强填料包括但不仅限于玻璃纤维、钛酸钾纤维、金属包层的玻璃纤维、陶瓷纤维、硅灰石纤维、金属碳化物纤维、金属固化纤维、石棉纤维、氧化铝纤维、碳化硅纤维、石膏纤维或硼纤维的一种或几种，优选为玻璃纤维；所述有机增强填料包括但不仅限于液晶聚酯纤维和/或碳纤维。
  12. 根据权利要求8所述的液晶聚酯模塑组合物，其特征在于，所述增强填料的形状为非纤维状，其平均粒径为0.001μm-50μm，选自钛酸钾晶须、氧化锌晶须、硼酸铝晶须、滑石粉、炭黑、石膏、石棉、沸石、绢云母、高岭土、蒙脱土、粘土、锂蒙脱土、合成云母、硅铝酸盐、二氧化硅、氧化钛、氧化铝、氧化锌、氧化锆、氧化铁、碳酸钙、钛酸镁、白云石、硫酸铝、硫酸钡、硫酸镁、碳酸钙、云母、石英粉、氢氧化镁、氢氧化钙、氢氧化铝、玻璃珠、陶瓷珠、氮化硼或碳化硅的一种或几种。
  13. 根据权利要求8所述的液晶聚酯模塑组合物，其特征在于，所述其他助剂选自抗氧化剂、热稳定剂、紫外线吸收剂、润滑剂、脱模剂、着色剂、增塑剂或抗静电剂中的一种或几种。
  14. 根据权利要求8-13任一项所述的液晶聚酯模塑组合物，其特征在于，采用差示扫描量热DSC测试，从室温起以20℃/min的升温速率升温到熔点+30℃的最高温度，在此温度下停留3min后再以20℃/min的速率降至室温，得到液晶聚酯模塑组合物的结晶曲线，选取结晶峰的结晶起始温度和结晶结束温度，并计算出结晶峰面积即为H(结晶焓)；测试样品在室温下停留3min后再次以20℃/min的升温速率升温到熔点+30℃的最高温度，得到液晶聚酯模塑组合物的第二次熔融曲线，选取熔融峰的熔融起始温度和熔融结束温度，并计算出熔融峰面积即为H(熔融焓)，该液晶聚酯模塑组合物满足由下式(1)定义的双焓比大于等于0.2，小于1.0，优选大于等于0.5至小于等于0.9；
    (1)ΔH＝H(熔融焓)/H(结晶焓)。
  15. 根据权利要求8-14任一项所述的液晶聚酯模塑组合物在电子电气领域中的应用。
PCT/CN2017/071467 2016-02-01 2017-01-18 一种液晶聚酯以及由其组成的模塑组合物和其应用 WO2017133448A1 (zh)

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