JP2012149241A - Process for producing liquid crystalline polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a liquid crystalline polyester resin which can inhibit foaming and sublimation due to hydroquinone in the temperature rising process of polymerization and the depressurizing process and thereby increase yield, and improve continuous batch productivity and quality.SOLUTION: The process for producing a liquid crystalline polyester resin includes acetylating raw material monomers containing at least hydroquinone with acetic anhydride and carrying out acetic acid elimination/polycondensation by agitation with the use of a helical ribbon blade and depressurization is initiated at an acetic acid fraction of 90% or more in the acetic acid elimination/polycondensation step.

Description

The present invention can suppress foaming and liquid level rise due to hydroquinone during deacetic acid polycondensation, suppress sublimation of hydroquinone and adhesion of the reaction liquid to the top of the stirring blade, and improve continuous batch productivity and quality. The present invention relates to a method for producing a liquid crystalline polyester resin.

  Demand for liquid crystalline polyester resins is growing, mainly for small precision molded products for electrical and electronic applications, taking advantage of its excellent heat resistance, fluidity, and electrical properties. In recent years, attention has been paid to its thermal stability and high thermal dimensional accuracy, and studies have been made on use as a support base for heat-generating components, such as a liquid crystal display support base for OA devices and mobile phones, and structural parts for lamps.

  The raw material of the liquid crystalline polyester resin is mainly composed of p-hydroxybenzoic acid or 6-hydroxy-2-naphthoic acid, and hydroquinone, 4,4′-dihydroxybiphenyl, 2,6-naphthalenediol, fat as a copolymer component. A diol such as an aromatic diol, a dicarboxylic acid such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and aliphatic dicarboxylic acid, and an amino group-containing monomer such as p-aminobenzoic acid and aminophenol. In the system using hydroquinone, by improving the slurry mixing method of raw material monomer and acetic anhydride, the complex derived from hydroquinone and p-hydroxybenzoic acid is suppressed, and the sublimation due to the heat generation of hydroquinone during the heating process of polymerization is suppressed. Methods have been studied (see Patent Documents 1 and 2).

  On the other hand, by regulating the polymerization stirring blade and regulating the stirring shear rate, it is possible to control the sublimates during the polycondensation reaction, lengthen the washing cycle, and regulate the distillation rate of acetic acid when transferring the reaction liquid. Thus, there has been proposed a method in which a filter can be used (see Patent Documents 3 to 7).

  Furthermore, a method has been proposed in which the apparatus temperature in the portion above the liquid surface during the polycondensation reaction is kept at a specified temperature, thereby suppressing the attachment of sublimates and preventing the clogging of the distilling pipe (see Patent Document 8). ).

JP 2008-74899 A (Claims) JP 2009-57402 A (Claims) Japanese Patent Laid-Open No. 4-225022 (Claims) Japanese Patent Laid-Open No. 4-225023 (Claims) Japanese Patent Laid-Open No. 10-7780 (Claims) JP-A-8-151448 (Claims) JP 2001-278988 A (Claims) International Publication No. 2003/062299 (Claims)

  As described in these patent documents, by improving the slurry mixing method of a monomer containing hydroquinone and acetic anhydride, the formation of a complex of hydroquinone, p-hydroxybenzoic acid and acetic anhydride is suppressed, and hydroquinone in the process of raising the temperature of polymerization In these methods, depending on the stirring state of the polycondensation reaction and the degree of distillation of acetic acid, foaming or sublimation due to hydroquinone occurs after the start of decompression. There are problems that the polymerization rate decreases, the yield of the product decreases, and the continuous batch productivity decreases.

  The present invention suppresses bubbling and sublimation due to hydroquinone in the polymerization temperature rising process and decompression process, suppresses the sublimation of the reaction liquid and adhesion of the reaction liquid to the upper part of the stirring blade, and can improve the yield, continuous batch production It is an object of the present invention to provide a method for producing a liquid crystalline polyester resin capable of improving the properties and quality.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors start stirring under a helical ribbon blade and start depressurization after the acetic acid distillation rate reaches a certain level or more when performing deacetic acid polycondensation. And found that continuous batch productivity and quality can be improved.

  That is, the present invention is a method for producing a liquid crystalline polyester resin in which a raw material monomer containing at least hydroquinone is acetylated with acetic anhydride, and deaceticated polycondensed by stirring with a helical ribbon blade. In this process, the liquid crystal polyester resin is produced by starting pressure reduction at an acetic acid distillation rate of 90% or more.

  According to the method for producing a liquid crystalline polyester resin of the present invention, it is possible to suppress foaming and liquid level rise due to hydroquinone during deacetic acid polycondensation, improve the product yield, and improve continuous batch productivity and quality. can do.

FIG. 1 is a schematic view illustrating a helical ribbon wing having no central axis. FIG. 2 is a schematic view illustrating a helical ribbon wing having a central axis.

  The liquid crystalline polyester resin of the present invention is a resin that forms an anisotropic molten phase, and examples thereof include liquid crystalline polyester resins having an ester bond such as liquid crystalline polyester and liquid crystalline polyester amide.

  Specific examples of the liquid crystalline polyester resin include a structural unit generated from p-hydroxybenzoic acid, a structural unit generated from 4,4′-dihydroxybiphenyl, a structural unit generated from hydroquinone, and generated from terephthalic acid and / or isophthalic acid. Liquid crystalline polyester resin composed of structural units, structural units generated from p-hydroxybenzoic acid, structural units generated from ethylene glycol, structural units generated from 4,4′-dihydroxybiphenyl, structural units generated from hydroquinone, terephthalate Liquid crystalline polyester resin comprising structural units formed from acid and / or isophthalic acid, structural units formed from p-hydroxybenzoic acid, structural units formed from hydroquinone, structural units formed from 4,4′-dihydroxybiphenyl, 2 , 6-Na Examples thereof include a liquid crystalline polyester resin composed of a structural unit generated from tylene dicarboxylic acid and a structural unit generated from terephthalic acid. Among them, preferred combinations include p-hydroxybenzoic acid, hydroquinone, 4,4′-dihydroxybiphenyl, terephthalate. Examples include acids and / or isophthalic acid.

  Examples of monomers used in addition to hydroquinone and p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl, terephthalic acid, and isophthalic acid include aromatic hydroxycarboxylic acids such as 6-hydroxy-2-naphthoic acid, Examples of the aromatic dicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, 1,2-bis ( 2-chlorophenoxy) ethane-4,4′-dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid and the like. Examples of the aromatic diol include resorcinol, t-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 3,4'-dihydroxybiphenyl, 2,2-bis (4- Hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl ether, and the like. Examples of the monomer having an amino group include p-aminobenzoic acid and p-aminophenol.

  Preferable examples of the liquid crystalline polyester resin forming the anisotropic molten phase include liquid crystalline polyester resins comprising the following structural units (I), (II), (III), (IV) and (V). .

  The structural unit (I) is a structural unit generated from p-hydroxybenzoic acid, the structural unit (II) is a structural unit generated from 4,4′-dihydroxybiphenyl, and the structural unit (III) is generated from hydroquinone. The structural unit, the structural unit (IV) represents a structural unit produced from terephthalic acid, and the structural unit (V) represents a structural unit produced from isophthalic acid.

  Hereinafter, this liquid crystalline polyester resin will be described as an example.

  The copolymerization amount of the structural units (I), (II), (III), (IV) and (V) is arbitrary. However, in order to make it the range prescribed | regulated by this invention and to exhibit the characteristic, it is preferable that it is the following copolymerization amount.

  That is, the structural unit (I) is preferably 65 to 80 mol% with respect to the total of the structural units (I), (II) and (III). More preferably, it is 68-78 mol%. Moreover, it is preferable that structural unit (II) is 55-85 mol% with respect to the sum total of structural unit (II) and (III). More preferably, it is 55-78 mol%, Most preferably, it is 58-73 mol%. The structural unit (IV) is preferably 50 to 95 mol% with respect to the total of the structural units (IV) and (V). More preferably, it is 55-90 mol%, Most preferably, it is 60-85 mol%.

  The sum of structural units (II) and (III) and the sum of (IV) and (V) are substantially equimolar. Here, “substantially equimolar” means that the structural unit constituting the polymer main chain excluding the terminal is equimolar. For this reason, the aspect which does not necessarily become equimolar when it includes even the structural unit which comprises the terminal can satisfy the requirement of “substantially equimolar”.

  The liquid crystalline polyester resin preferably used includes aromatic dicarboxylic acids such as 3,3′-diphenyldicarboxylic acid and 2,2′-diphenyldicarboxylic acid in addition to the components constituting the structural units (I) to (V). , Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl Aromatic diols such as sulfone, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxybenzophenone, 3,4′-dihydroxybiphenyl, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neo Pentyl glycol, 1,4-cyclohexa Diol, aliphatic, such as 1,4-cyclohexane dimethanol, an alicyclic diol and m- hydroxybenzoic acid, can be allowed to further copolymerization in a range that does not impair the liquid crystalline and characteristics.

In the embodiment of the present invention, the content of each structural unit in the liquid crystalline polyester resin can be calculated by the following treatment. That is, the liquid crystalline polyester is weighed into an NMR (nuclear magnetic resonance) test tube, dissolved in a solvent in which the liquid crystalline polyester is soluble (for example, a pentafluorophenol / heavy tetrachloroethane-d ₂ mixed solvent), and ¹ H- NMR spectrum measurement is performed. The content of each structural unit can be calculated from the peak area ratio derived from each structural unit.

  For example, in the production of the liquid crystalline polyester resin, the following production method is preferably exemplified. The following is an example of the synthesis of a liquid crystalline polyester resin composed of p-hydroxybenzoic acid and 4,4′-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid. It is not limited, It can replace with each other hydroxycarboxylic acid, aromatic diol, or aromatic dicarboxylic acid, and can manufacture according to the following method.

  Hereinafter, the manufacturing method of the liquid crystalline polyester resin of the present invention will be described in detail.

  For example, a predetermined amount of a monomer mixture and acetic anhydride are charged into a reaction vessel equipped with a stirring blade, a rectifying column, and a distillation pipe, with a discharge port at the bottom, and heated under reflux in a nitrogen gas atmosphere. While acetylating the hydroxyl group. Next, the reflux path is switched to a distillation pipe, the temperature is raised to a predetermined temperature while distilling acetic acid, and acetic acid is distilled to a specified amount. Next, the pressure in the reaction vessel is reduced, and acetic acid generated by the polycondensation reaction is distilled off. When the prescribed stirring torque is reached, the deacetic acid polycondensation reaction is terminated. When the polycondensation reaction is completed, stirring is stopped, the reaction vessel is pressurized with nitrogen, is formed into a strand shape from the bottom of the reaction vessel via a base, and is pelletized with a cutting device.

The production method of the liquid crystalline polyester resin of the present invention, when producing a liquid crystalline polyester resin by these deacetic acid polycondensation, in producing a liquid crystalline polyester resin by deacetic acid polycondensation using a helical ribbon blade, Hydroquinone is an essential component as a raw material monomer, an acetylation reaction is performed using acetic anhydride, and pressure reduction is started at an acetic acid distillation rate of 90% or more. The acetic acid distillation rate is a value obtained from the following formula (1).
Acetic acid distillation rate (%) = distillate amount (g) / [[number of moles of acetic anhydride charged−number of moles of hydroxyl group in raw material monomer] × acetic anhydride molecular weight + number of moles of hydroxyl group in raw material monomer × 2 × Acetic acid molecular weight + mol number of acetyl groups in raw material monomer × acetic acid molecular weight] (g) × 100 (%) (1).

  In the present invention, the number of reaction tanks is not particularly limited, and the reaction can be performed in one tank or two or more reaction tanks. A preferred method example in the case of performing two tanks is as follows. First, after the raw material monomer and acetic anhydride are charged into the reaction tank 1 and subjected to acetylation reaction, deacetic acid polycondensation is performed up to a predetermined temperature and a predetermined amount of acetic acid distillate. Next, the reaction liquid in the reaction tank 1 is transferred to the reaction tank 2 through a transfer pipe connected to the reaction tank 2, and deacetic acid polycondensation is further performed to a predetermined temperature and a predetermined amount of acetic acid distillate. Then, the polycondensation is further advanced, and the reaction is terminated when a predetermined stirring torque is reached.

  It is preferable that the usage-amount of acetic anhydride is 1.00-1.20 molar equivalent of the sum total of the phenolic hydroxyl group in the liquid crystalline polyester resin raw material to be used. More preferably, it is 1.03-1.16 molar equivalent. The acetylation reaction is preferably carried out while refluxing at a temperature of 125 ° C. or higher and 150 ° C. or lower until the residual amount of monoacetylated aromatic diol falls within a specific range. As an apparatus for the acetylation reaction, for example, a reaction vessel equipped with a reflux tube, a rectifying column, and a condenser can be used. The reaction time of acetylation is roughly 1 to 5 hours, but the time until the residual amount of monoacetylated aromatic diol reaches a specific range depends on the liquid crystalline polyester resin raw material used and the reaction temperature. Is also different. Preferably, the time is 1.0 to 2.5 hours. The higher the reaction temperature, the shorter the time, and the higher the molar ratio of acetic anhydride to the phenolic hydroxyl terminal, the shorter the time.

  When raising the temperature to a predetermined temperature while distilling acetic acid, it is preferable that the top temperature of the rectifying column is in the range of 115 ° C to 150 ° C. More preferably, it is the range of 130 degreeC-145 degreeC. If the column top temperature is too low, a large amount of unreacted acetic anhydride remains in the system, which is not preferable because it causes the coloring of the polymer and increases the amount of gas during heat retention. On the other hand, when the column top temperature is higher than 150 ° C., the monomers are distilled out of the system, which is not preferable because the composition shifts or the polymerization rate decreases. In this case, although acetic anhydride and monomers are included in the distilled acetic acid, the mass% of monomers excluding acetic acid and acetic anhydride is preferably 1% or less, more preferably 0.5% or less. .

  The production method of the present invention uses a reaction vessel equipped with a helical ribbon blade as a stirring blade. The helical ribbon blade is one in which a ribbon blade is spirally attached to the frame of the stirring shaft, and examples thereof include those shown in FIGS. The helical ribbon wing of FIG. 1 is a helical ribbon wing in which a ribbon wing is attached to a frame that does not have a central axis (hereinafter referred to as a helical ribbon wing that does not have a central axis). The helical ribbon blade not having the central axis is fixed to the rotating shaft 1, the fixed rod 6 which is fixed to the end of the rotating shaft 1 and whose longitudinal direction is the diameter direction of the reaction vessel 5, and fixed to both ends of the fixed rod. Two or more frame bars 2 whose directions are parallel to the wall surface of the reaction vessel 5, and a ribbon blade 3 fixed while being spirally wound around the frame bars 2. Each frame rod is located at a distance from the wall of the reaction vessel 5 within 0.2 times the inner diameter of the reaction vessel. As the rotary shaft 1 rotates, the ribbon blade 3 rotates in the reaction vessel 5 around the rotary shaft 1. The helical ribbon blade of FIG. 2 is fixed to the rotating shaft 1 that also serves as a central axis, a plurality of fixing rods 6 that are fixed to the rotating shaft 1 and whose longitudinal direction is the diameter direction of the reaction vessel 5, and fixed to the end of the fixing rod 6. It is comprised with the ribbon blade | wing 3 which advances spirally along the reaction vessel 5 wall surface. The clearance of the helical ribbon blade 3 from the wall surface of the reaction vessel 5 is preferably 50 mm or less. More preferably, it is 20 mm or less.

  In order to suppress the reaction liquid from rising due to hydroquinone bubbling or sublimation, the rotational direction of the helical ribbon blade is more preferably a scraping direction. The scraping direction here means that the reaction liquid near the can wall surface is pushed down toward the bottom of the can by the rotation direction of the ribbon blade. Conversely, the scraping direction means that the reaction liquid near the can wall surface is pushed upward by the rotation direction of the ribbon blade.

Furthermore, in order to achieve a more efficient stirring and mixing state, the stirring shear rate before decompression is preferably in the range of 150 to 500 (1 / second). The lower limit of the stirring shear rate is more preferably 200 (1 / second) or more. The upper limit of the stirring shear rate is more preferably 350 (1 / second) or less. The stirring shear rate refers to a value obtained by the following equation (2) for the shear rate between the stirring blade and the can wall surface.
・ Shear rate (1 / second) = 2 × 2 × 3.14 × number of stirring (rotation / second) × can inner diameter × can inner diameter / (can inner diameter × can inner diameter−stirring blade outer diameter × stirring blade outer diameter). (2).

  A lower limit of the stirring shear rate is preferably 150 (1 / second) or more because a reaction liquid containing hydroquinone can be mixed uniformly. If the upper limit of the stirring shear rate is 500 (1 / second) or less, it is preferable because the scattering of the reaction liquid and the sublimated material due to the high-speed stirring and mixing can be suppressed.

  Further, as the helical ribbon wing, a helical ribbon wing having no central axis is preferable. When using a helical ribbon blade that does not have a central axis, the amount of polymer adhering to the central part of the stirring shaft with a low shear rate is small, the residual polymer can be reduced as much as possible, and there is no abnormal stagnation near the central axis. The reaction liquid is stirred uniformly, a uniform reaction liquid with a small internal temperature distribution can be obtained, and a good liquid crystalline polyester resin can be obtained.

  Furthermore, when the polycondensation reaction is performed with the helical ribbon blade, it is necessary to reduce the pressure after sufficiently reacting hydroquinone. Therefore, the pressure reduction is preferably started when the acetic acid distillation rate is 90% or more. More preferably, it is 93% or more. If the acetic acid distillation rate is less than 90%, the reaction of hydroquinone is insufficient, so that after the pressure reduction is started, the sublimate is scattered toward the pressure reduction device or the foaming of hydroquinone is promoted, which is not preferable. The pressure during polycondensation after 90% acetic acid distillation rate is preferably reduced to 1333 Pa or less, more preferably 133 Pa or less.

  The final polymerization temperature is preferably about melting point + 20 ° C., preferably 370 ° C. or less.

  After the polycondensation reaction is completed, in order to take out the obtained polymer from the reaction vessel, the inside of the reaction vessel is pressurized to, for example, approximately 0.02 to 0.5 MPa at a temperature at which the polymer melts, and the discharge provided at the lower part of the reaction vessel is provided. A strand is discharged from the outlet, and the strand is cooled in cooling water and cut into pellets to obtain resin pellets. The melt polymerization method is an advantageous method for producing a uniform polymer, and is preferable because an excellent polymer with less gas generation can be obtained.

  When the liquid crystalline polyester resin of the present invention is produced, the polycondensation reaction can be completed by a solid phase polymerization method. For example, the polymer or oligomer of the liquid crystalline polyester resin of the present invention is pulverized by a pulverizer, and the temperature of the liquid crystalline polyester resin ranges from -5 ° C to -50 ° C for 1 to 50 hours under a nitrogen stream or under reduced pressure. A method of heating and polycondensing to a desired degree of polymerization to complete the reaction can be mentioned. Solid phase polymerization is an advantageous method for producing polymers with a high degree of polymerization.

  The melt viscosity of the liquid crystalline polyester resin in the present invention is preferably 10 to 500 Pa · s. More preferably, it is 12-200 Pa.s. This melt viscosity is a value measured by a Koka flow tester under the condition of melting point (Tm) + 10 ° C. and shear rate of 1000 (1 / second).

  The melting point of the liquid crystalline polyester resin in the present invention is not particularly limited, but it is preferable to combine the copolymer components so as to be 280 ° C. or higher for use in high heat resistance applications.

  The polycondensation reaction of the liquid crystalline polyester resin proceeds even without catalyst, but metal compounds such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, and metal magnesium can also be used.

  In the present invention, in order to impart mechanical strength and other characteristics of the liquid crystalline polyester resin, a filler can be further blended. The filler is not particularly limited, but fillers such as a fiber, a plate, a powder, and a granule can be used. Specifically, for example, glass fibers, PAN and pitch carbon fibers, stainless fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers and liquid crystalline polyester fibers, gypsum fibers, ceramic fibers Asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, basalt fiber, titanium oxide whisker, potassium titanate whisker, barium titanate whisker, aluminum borate whisker, silicon nitride whisker, etc. Fibrous, whisker-like filler, mica, talc, kaolin, silica, glass beads, glass flakes, glass microballoons, clay, molybdenum disulfide, wollastonite, titanium oxide, zinc oxide, calcium polyphosphate and graphite Which powder include particulate or plate-like filler. The above-mentioned filler used in the present invention can be used by treating the surface thereof with a known coupling agent (for example, a silane coupling agent, a titanate coupling agent, etc.) or other surface treatment agents. .

  Among these fillers, glass fiber is particularly preferably used from the viewpoint of balance between availability and mechanical strength. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing resin, and can be selected from, for example, long fiber type or short fiber type chopped strands and milled fibers. Two or more of these can be used in combination. As the glass fiber used in the present invention, a weakly alkaline glass fiber is excellent in terms of mechanical strength and can be preferably used. The glass fiber is preferably treated with an epoxy-based, urethane-based, acrylic-based coating or sizing agent, and epoxy-based is particularly preferable. Further, it is preferably treated with a silane-based or titanate-based coupling agent or other surface treatment agent, and an epoxysilane or aminosilane-based coupling agent is particularly preferable.

  The glass fiber may be coated or bundled with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin.

  The blending amount of the filler is usually 30 to 200 parts by mass, preferably 40 to 150 parts by mass with respect to 100 parts by mass of the liquid crystalline polyester resin.

  Furthermore, the liquid crystalline polyester resin of the present invention includes antioxidants and heat stabilizers (for example, hindered phenols, hydroquinones, phosphites, and substituted products thereof), ultraviolet absorbers (for example, resorcinol, salicylate), phosphorous acid. Coloring agents including acid salts, hypophosphites, etc., lubricants and mold release agents (such as montanic acid and its metal salts, its esters, their half esters, stearyl alcohol, stearamide and polyethylene wax), dyes and pigments Carbon black, crystal nucleating agent, plasticizer, flame retardant (bromine flame retardant, phosphorus flame retardant, red phosphorus, silicone flame retardant, etc.), flame retardant aid, and antistatic agent Ordinary additives such as polymers and polymers other than thermoplastic resins are blended to further impart the prescribed characteristics. Can.

  The method of blending these additives is preferably by melt kneading, and known methods can be used for melt kneading. For example, using a Banbury mixer, rubber roll machine, kneader, single-screw or twin-screw extruder, etc., the liquid crystalline polyester resin composition may be melt kneaded at a temperature of 200 to 370 ° C., more preferably 270 to 340 ° C. it can. In that case, 1) a liquid crystal polyester resin, a bulk kneading method with fillers and other additives as optional components, and 2) a liquid crystal polyester resin containing a high concentration of other additives in the liquid crystal polyester resin. A method of preparing a composition (master pellet) and then adding other thermoplastic resin, filler and other additives to a specified concentration (master pellet method), 3) Liquid crystalline polyester resin and other Any method may be used, such as a split addition method in which a part of the additive is once kneaded and then the remaining filler and other additives are added.

  The liquid crystalline polyester resin of the present invention and the liquid crystalline polyester resin composition containing the same are excellent in surface appearance (color tone) and mechanical properties, heat resistance, by a molding method such as normal injection molding, extrusion molding, and press molding. It can be processed into flame-retardant three-dimensional molded products, sheets, containers, pipes, films and the like. In particular, it is suitable for electrical and electronic parts obtained by injection molding.

  The liquid crystalline polyester resin thus obtained and the liquid crystalline polyester resin composition containing the same are, for example, various gears, various cases, sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, Capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, housings, semiconductors, liquid crystal display parts, Electrical and electronic parts represented by FDD carriage, FDD chassis, HDD parts, motor brush holder, parabolic antenna, computer-related parts; VTR parts, TV parts, iron, hair dryer, rice cooker part , Microwave oven parts, acoustic parts, audio equipment parts such as audio / laser discs / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, home appliances such as office appliances, office computers Machine-related parts such as related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, various bearings such as oilless bearings, stern bearings, underwater bearings, motor parts, lighters, typewriters, etc. , Optical instruments such as microscopes, binoculars, cameras, watches, precision machine related parts; alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, various valves such as exhaust gas valves, fuel and exhaust systems Various intake system pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air Flow meter, brake pad wear sensor, thermostat base for air conditioner, motor insulator for air conditioner, separator, heating air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, distributor Starter switch, starter relay, transmission wiring harness, window opening Sher nozzle, air conditioner panel switch board, coil for fuel related electromagnetic valve, fuse connector, horn terminal, electrical component insulation plate, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition It can be used for automobile / vehicle-related parts such as device cases. When used as a film, magnetic recording media film, photographic film, capacitor film, electrical insulation film, packaging film, drafting film, ribbon film, and sheet use as automotive interior ceiling, door trim, instrument panel It is useful for pad materials, bumper and side frame cushioning materials, sound absorbing pads such as the back of bonnets, seat materials, pillars, fuel tanks, brake hoses, nozzles for window washer fluid, air conditioner refrigerant tubes and their peripheral components.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited by these.

  The polymerization steps of Examples 1 to 6 and Comparative Examples 1 to 5 were each performed 20 times (20 batches) at maximum, and the evaluations shown in the following (1) to (4) were performed.

(1) Number of batches with defective decompression The batch reaction was repeated, and the number of batches in which control failure during vacuuming or fluctuation in vacuum began to occur was examined.

(2) Number of batches with clogged caps The batch reaction was repeated, and the number of batches in which the caps at the discharge ports began to clog was examined.

(3) Product yield The product yield was calculated | required for every test batch. And the average value of all the test batches was made into the product yield of each Example and a comparative example. In addition, when the test was completed with less than 20 batches, an average value up to the finished batch was obtained.
Product yield (%) = pellet mass (kg) / theoretical polymer mass (kg) × 100.

(4) Color tone (L value)
The brightness (L value) of the pellets obtained for each test batch was measured using an SM color computer device manufactured by Suga Test Instruments Co., Ltd. And the average value of all the test batches was made into the color tone (L value) of each Example and a comparative example. In addition, when the test was completed with less than 20 batches, an average value up to the finished batch was obtained.

Example 1
Polymerization was carried out as follows using a 5 L reaction vessel having a distillation pipe and a gap between the inner wall of the vessel and a helical ribbon blade having no central axis of 10 mm.
In a reaction vessel, 843 parts by mass (54 mol%) of p-hydroxybenzoic acid, 341 parts by mass of 4,4'-dihydroxybiphenyl (16 mol%), 86 parts by mass of hydroquinone (7 mol%), 282 parts by mass of terephthalic acid (15 Mol%), 152 parts by mass (8 mol%) of isophthalic acid, and 1272 parts by mass of acetic anhydride (1.10 equivalents of the total phenolic hydroxyl group), and scraped down under a nitrogen gas atmosphere at a shear rate of 285 (1 / second) The mixture was allowed to acetylate at 145 ° C. for 1.5 hours with stirring in the direction, and then heated to 335 ° C. over 4 hours while distilling acetic acid. At this time, when the acetic acid distillate reaches 95% of the theoretical distillate, the pressure reduction is started, the pressure is reduced to 133 Pa (1 torr) over 1 hour, and when the acetic acid distillate reaches 13.3 kPa (100 torr), the stirring shearing is performed. The speed was changed to 180 (1 / second), and the polycondensation reaction was continued while further reducing the pressure. When the prescribed stirring torque was reached, the polycondensation reaction was terminated. Next, the inside of the reaction vessel was pressurized to 0.1 MPa with nitrogen, the polymer was discharged into a strand-like material via a die having a circular discharge port with a diameter of 10 mm, and pelletized by a cutter. 20 batches of polymerization were repeatedly carried out by the above-mentioned method.

(Example 2)
The same procedure as in Example 1 was performed except that the pressure reduction was started when the acetic acid distillation rate reached 90%. Compared to Example 1, the vacuum fluctuation at the time of depressurization started to occur in the 17th batch, but since it was slight, 20 batches could be continuously operated.

(Example 3)
The same procedure as in Example 1 was performed except that the stirring shear rate until the start of pressure reduction was 180 (1 / second). Compared to Example 1, clogging of the base began to be seen at the 18th batch, but it was slight and continuous operation of 20 batches was possible.

Example 4
The same procedure as in Example 1 was performed except that the rotational direction of the helical ribbon blade was changed to the scraping direction. Compared to Example 1, a vacuum fluctuation at the time of depressurization started to occur in the 18th batch, and clogging of the base started to appear in the 16th batch, but it was slight and continuous operation of 20 batches was possible. When the upper part of the reaction vessel was disassembled after the completion of 20 batches and the internal inspection was performed, polymer adhesion was slightly observed on the gas phase portion of the inner wall.

(Example 5)
The same operation as in Example 1 was performed except that a helical ribbon blade having a central axis was used. Compared to Example 1, clogging of the base began to be observed at the 14th batch, but it was slight and continuous operation of 20 batches was possible. After the completion of 20 batches, the upper part of the reaction vessel was disassembled and the inside of the reaction vessel was inspected, and polymer adhesion was observed on the central shaft portion of the stirring blade.

(Example 6)
The same operation as in Example 1 was performed except that the stirring shear rate until the start of pressure reduction was set to 450 (1 / second). Compared to Example 1, a fluctuation in the degree of vacuum at the time of depressurization started to occur in the 15th batch, but it was slight and continuous operation of 20 batches was possible. When the decompression line was inspected after the experiment, about 10% of the piping was clogged with sublimation.

(Comparative Example 1)
The same operation as in Example 1 was performed except that an anchor type stirring blade having a central axis was used. Since the clogging of the base began to be observed repeatedly in the third batch, and the clogging became severe thereafter, the base was replaced after the discharge of the sixth batch. In addition, the vacuum fluctuation at the time of depressurization began to occur repeatedly in the 7th batch, and the fluctuation of the vacuum level became large thereafter. When the depressurization line was inspected after the 10th batch was discharged, about half of the piping was blocked with sublimation. The experiment was stopped in this batch. The polymerization time after reaching the degree of vacuum of 1333 Pa was delayed as 124 minutes (average of 10 batches).

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the pressure reduction was started when the acetic acid distillation rate reached 85%. From the first batch, the degree of vacuum started to be disturbed, and the degree of vacuum fluctuation was large until the reaction was completed. When the decompression line was inspected after discharging the first batch, about 80% of the piping was clogged with sublimation, so the sublimation was removed and the second batch was reacted, but vacuum was applied as in the first batch. Since the degree of vibration was large, the experiment was completed in the second batch. When the decompression line is inspected after the second batch discharge, most of the piping is clogged with sublimates, and when the reaction vessel upper part is disassembled and the inside of the reaction vessel is inspected, the stirring blade and the gas phase part of the inner wall are very Many sublimates were attached. The polymerization time after reaching the degree of vacuum of 1333 Pa was significantly delayed to 261 minutes (average of 2 batches), the product yield was as low as 85.3%, and the pellets were also blackish.

(Comparative Example 3)
Polymerization was carried out in the same manner as in Example 1 except that the components charged in the reaction vessel were changed to the following.
・ 1152 parts by mass of p-hydroxybenzoic acid (74 mol%)
・ 146 parts by mass of 4,4′-dihydroxybiphenyl (7 mol%)
-130 parts by mass of terephthalic acid (7 mol%)
・ 251 parts by mass of polyethylene terephthalate (12 mol%)
-1113 parts by mass of acetic anhydride (1.10 equivalents of total phenolic hydroxyl groups)
In the third batch, the fluctuation of the vacuum at the time of decompression began to occur, and the fluctuation of the degree of vacuum continued to increase. After checking the decompression line after the sixth batch, most of the piping was clogged with sublimation. When the reaction vessel upper part was disassembled and the inside of the reaction vessel was inspected, a large amount of sublimate adhered to the gas phase part of the stirring blade and the inner wall. It was decided to continue driving. In addition, the clogging of the base started to be seen in the fifth batch, and then the clogging became severe and the fluctuation of the degree of vacuum became large. Therefore, the experiment was stopped after the discharge of the eighth batch was completed. In the current discharge state, strands were foamed severely in all batches, making it difficult to take up the cutter, and it was necessary to interrupt the discharge several times. Moreover, the pellet surface was tinged with fine bubbles, and many powdery pellets were mixed. The polymerization time after reaching the degree of vacuum of 1333 Pa was delayed as 102 minutes (average of 8 batches).

(Comparative Example 4)
The same procedure as in Example 1 was performed except that the pressure reduction was started when the acetic acid distillation rate reached 89%. From the 10th batch, the degree of vacuum started to appear, and from the 15th batch, clogging of the base began to be observed. Thereafter, the fluctuation of the degree of vacuum at the time of decompression gradually increased, but continuous operation of 20 batches was possible. When the decompression line was inspected after 20 batches, about half of the piping was clogged with sublimation.

(Comparative Example 5)
The same procedure as in Comparative Example 1 was carried out except that the stirring shear rate until the start of pressure reduction was 510 (1 / second) and the pressure reduction was started when the acetic acid distillation rate reached 85%. From the first batch, disorder of vacuum and clogging of the mouth were observed, and the fluctuation of vacuum was large until the reaction was completed. Since the increase in stirring torque after reaching a vacuum degree of 1333 Pa was slow, the polymerization was terminated in 360 minutes. When the decompression line was inspected after discharging the first batch, about 80% of the piping was clogged with sublimation, so the sublimation was removed and the second batch was reacted, but vacuum was applied as in the first batch. The runout was large and the clogging of the base became severe, so the experiment was completed in the second batch. When the decompression line is inspected after the second batch discharge, most of the piping is clogged with sublimates, and when the reaction vessel upper part is disassembled and the inside of the reaction vessel is inspected, the stirring blade and the gas phase part of the inner wall are very Many sublimates were attached. The polymerization time after reaching the degree of vacuum of 1333 Pa was significantly delayed to 360 minutes (both batches were cut off at 360 minutes), the product yield was the lowest at 77.1%, and the pellets were blackish.

  The results of each example and comparative example are summarized in Tables 1 and 2.

1 Rotation axis (center axis)
2 Frame rod 3 Helical ribbon blade 4 Bottom blade 5 Reaction vessel 6 Fixed rod

Claims (5)

  A method for producing a liquid crystalline polyester resin in which a raw material monomer containing at least hydroquinone is acetylated with acetic anhydride and deaceticated polycondensed by stirring with a helical ribbon blade. A method for producing a liquid crystalline polyester resin, wherein pressure reduction is started at a yield of 90% or more.   The method for producing a liquid crystalline polyester resin according to claim 1, wherein in the deacetic acid polycondensation step, the stirring shear rate before the start of pressure reduction is 150 to 500 (1 / second).   The method for producing a liquid crystalline polyester resin according to claim 1, wherein the helical ribbon wing is a helical ribbon wing attached to a frame having no central axis.   4. The method for producing a liquid crystalline polyester resin according to claim 1, wherein in the deacetic acid polycondensation step, the rotational direction of the helical ribbon blade is the scraping direction. The liquid crystalline polyester resin is composed of the following structural units (I), (II), (III), (IV) and (V), and the structural unit (I) is the structural units (I), (II) and (III). ) To 65 to 80 mol%, the structural unit (II) is 55 to 85 mol% to the total of the structural units (II) and (III), and the structural unit (IV) is the structural unit. 50 to 95 mol% with respect to the sum of (IV) and (V), and the sum of structural units (II) and (III) and the sum of structural units (IV) and (V) are substantially equimolar It is a certain liquid crystalline polyester resin, The manufacturing method of the liquid crystalline polyester resin in any one of Claims 1-4.

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