JP3484906B2 - Pellet and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystalline resin pellet and a method for producing the same. More specifically, the present invention relates to pellets of a liquid crystalline resin having a shape excellent in supplyability and quantification represented by measurement stability, and a production method for obtaining the pellets.

[0002]

2. Description of the Related Art In recent years, the demand for higher performance of plastics has been increasing, and many polymers having various new properties have been developed. Among them, an optically anisotropic liquid crystal characterized by parallel arrangement of molecular chains. Resin has attracted attention because it has excellent fluidity and mechanical properties.

As a method for producing a liquid crystalline polyester, a melt polymerization method (JP-A-62-277427), a bulk polymerization method (JP-A-57-151619), and a solid phase polymerization method (JP-A-60-190449). Gazette) and the like, and inorganic fillers, antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, release agents, colorants for the purpose of improving functions such as mechanical strength,
As a method for filling ordinary additives such as a plasticizer, an antistatic agent, a flame retardant and other thermoplastic resins, a melt-kneading method using an extruder is generally known.

Further, as a method of producing pellets of a thermoplastic resin or a thermoplastic resin composition, molten polymer that has passed through a die provided at a discharge outlet is extruded in a string shape, cooled with cooling water, and then fixed to a rotary blade. The method of cutting into pellets using a cutter having a blade (cold cut method) is most commonly used. Further, in order to further improve the yield of pellets in the above-mentioned method, there is a method in which a molten polymer is flowed in a trough in a string shape and is cut by a cutter in the presence of cooling water.

[0005]

However, since the liquid crystalline resin has a higher elastic modulus when cooled and solidified than other thermoplastic resins and has a tough fibrous material, only the above method can be used. , The cross section of the string-like material is not constant, is curved, or cracks occur in the pellet at the time of cutting, resulting in irregular pellet shapes due to mixing of debris / powder, etc. It has been found that the obtained pellets are apt to cause molding problems such as clogging at the raw material charging port of the extruder or the molding machine, that is, variations in the supply amount.

An object of the present invention is to solve the above-mentioned problems and to obtain pellets having a shape excellent in supplyability and quantitativeness represented by weighing stability.

[0007]

Means for Solving the Problems That is, the present invention provides (1) a pellet made of a liquid crystalline resin containing a liquid crystalline polymer, wherein the average weight per pellet is W (m
g), and the standard deviation is σ (mg), the value of σ / W is 0.
2 or less, the pellet according to (1) above, wherein (2) the liquid crystalline resin further contains a filler, (3) the liquid crystalline resin is a liquid crystalline polymer 10.
The pellet according to the above (2), which further contains 0.01 to 200 parts by weight of a filler with respect to 0 part by weight.
(4) The pellet according to (2) or (3) above, wherein the filler is at least one selected from inorganic and / or organic fillers, additives and other thermoplastic resins, and (5) the liquid crystalline polymer is p. -The pellet according to any one of (1) to (4) above, which contains a hydroxybenzoic acid residue as an essential component, and (6) the liquid crystalline polymer contains ethylenedioxy units as a constituent unit. 5 The pellet according to any one of (5), (7) the liquid crystalline polymer is the following structural unit
(I), (II), (III) and (IV) pellets according to the above (6),

[Chemical 4] (However, R ₁ in the formula is

[Chemical 5] R ₂ represents one or more groups selected from

[Chemical 6] And one or more groups selected from However, in the formula, X represents a hydrogen atom or a chlorine atom. (8) The total of the structural units (I) and (II) is 30 to 95 mol% with respect to the total of the structural units (I), (II) and (III), and the structural unit (III) is the structural unit.
70 to 5 mol% relative to the sum of (I), (II) and (III)
And the molar ratio [(I) / (II)] of the structural units (I) and (II) is 7
5/25 to 95/5, and the structural unit (IV) and the structural unit (I
The pellet of (7) above, in which the sum of I) and (III) is substantially equimolar, and (9) a string made of a liquid crystalline resin containing a liquid crystalline polymer, and A method of manufacturing pellets that is cut with a cutter that has a clearance of 0.01 mm between the moving blade and fixed blade of the cutter.
The method for producing a pellet, characterized in that it is 0.09 mm or less, (10) the string-like material is a string of liquid crystalline resin containing a liquid crystalline polymer in a molten state from a polymerization reaction tank after completion of polymerization of the liquid crystalline polymer. Or (11) the method for producing pellets according to the above (9), wherein the molten liquid crystalline resin is discharged in a string form from the extruder, A method for producing the pellet according to the above (10), wherein the pellet is cut with a cutter after passing through the gas layer.
(12) The method for producing a pellet according to the above (10), wherein a string-like material made of a liquid crystalline resin is cooled with cooling water and then cut with a cutter in the presence of the cooling water, (13) a moving blade of the cutter is rotated. A method for producing a pellet according to any one of (9) to (12) above, which is a blade, (14) The clearance between the movable blade and the fixed blade of the cutter is 0.015 mm or more and 0.07 mm or less. (9) A method for producing a pellet according to any one of (9) to (13) above, (15) The above (9) to (1) in which the liquid crystalline polymer contains a p-hydroxybenzoic acid residue as an essential component.
4) The method for producing pellets according to any one of 4), and (16) The method for producing pellets according to any one of (9) to (15), wherein the liquid crystalline resin further contains a filler. Is.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystalline polymer of the present invention is a polymer capable of forming anisotropy when melted, and examples thereof include liquid crystalline polyester, liquid crystalline polyesteramide, liquid crystalline polyester carbonate, and liquid crystalline polyester elastomer. Liquid crystal polyester and liquid crystal polyester amide are preferably used.

The above liquid crystalline polyester is a polyester which forms an anisotropic melt phase composed of structural units selected from aromatic oxycarbonyl units, aromatic dioxy units, aromatic dicarbonyl units, ethylenedioxy units and the like. Examples of the liquid crystal polyester amide include polyester amides that form an anisotropic melt phase composed of structural units selected from the structural units and aromatic iminocarbonyl units, aromatic diimino units, aromatic iminooxy units, and the like. Can be mentioned.

The liquid crystalline polymer preferably usable in the present invention is a liquid crystalline polymer containing a structural unit consisting of p-hydroxybenzoic acid as an aromatic oxycarbonyl unit, and a liquid crystalline polymer containing an ethylenedioxy unit as an essential component. Can also be preferably used. More preferably the following structural units (I), (III), (IV) or (I), (II), (I
II) and (IV) structural unit polyesters, most preferably (I), (II), (III) and (IV) structural unit polyesters.

[0011]

[Chemical 7] (However, R ₁ in the formula is

[Chemical 8] R ₁ represents one or more groups selected from

[Chemical 9] Represents one or more groups selected from Further, in the formula, X represents a hydrogen atom or a chlorine atom. )

The total of the structural units (II) and (III) and the structural unit (IV) are preferably substantially equimolar.

The above structural unit (I) is a structural unit formed from p-hydroxybenzoic acid, and the structural unit (II) is 4,4.
′ -Dihydroxybiphenyl, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, phenylhydroquinone, methylhydroquinone, 2,6-dihydroxynaphthalene, 2,7- Dihydroxynaphthalene,
A structural unit produced from an aromatic dihydroxy compound selected from 2,2-bis (4-hydroxyphenyl) propane and 4,4′-dihydroxydiphenyl ether, a structural unit (III) is a structural unit produced from ethylene glycol, Structural unit (IV) is terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, 1,2 ' -Bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and a structural unit formed from an aromatic dicarboxylic acid selected from 4,4'-diphenyl ether dicarboxylic acid are shown respectively. R _{1 of} these

[Chemical 10] And R ₂ is

[Chemical 11] Are particularly preferred.

The liquid crystalline polyester which can be preferably used in the present invention is the above structural unit (I), (III), (IV) or (I).
, (II), (III) and (IV), and the copolymerization amount of the above structural units (I), (II), (III) and (IV) is arbitrary. However, from the viewpoint of fluidity, the following copolymerization amount is preferable.

That is, the structural units (I), (III) and (I
In the case of a copolymer consisting of V), the structural unit (I) is 30 to 85 mol% based on the total of the structural units (I) and (III).
Is preferable, and 40-80 mol% is more preferable. Also,
The structural unit (IV) is preferably substantially equimolar to the structural unit (III).

On the other hand, the above structural units (I), (II), (III),
In the case of the copolymer composed of (IV), the total of the structural units (I) and (II) is preferably 30 to 90 mol% of the total of the structural units (I), (II) and (III), and 40 ˜85 mol% is more preferred. Further, the structural unit (III) is the structural unit (I), (I
The total amount of I) and (III) is preferably 70 to 10 mol%, more preferably 60 to 15 mol%. The molar ratio [(I) / (II)] of the structural units (I) and (II) is preferably 75.
/ 25 to 95/5, and more preferably 78/22 to
It is 93/7. Further, the structural unit (IV) is preferably substantially equimolar to the total of the structural units (II) and (III).

As the liquid crystalline polyesteramide,
A polyester amide forming an anisotropic melt phase containing a p-iminophenoxy unit formed from p-aminophenol in addition to the above structural units (I) to (IV) is preferable.

The liquid crystalline polyester and the liquid crystalline polyesteramide which can be preferably used are 3,3'-diphenyldicarboxylic acid and 2,2'-diphenyl in addition to the components constituting the structural units (I) to (IV). Aromatic dicarboxylic acids such as dicarboxylic acids, adipic acid, azelaic acid,
Aliphatic dicarboxylic acids such as sebacic acid and dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, chlorohydroquinone, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfone, 4,4'- Dihydroxydiphenyl sulfide,
Aromatic diols such as 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and aliphatic such as 1,4-cyclohexanedimethanol, To further copolymerize an alicyclic diol, an aromatic hydroxycarboxylic acid such as m-hydroxybenzoic acid or 2,6-hydroxynaphthoic acid, and p-aminophenol or p-aminobenzoic acid within a range not impairing liquid crystallinity. You can

The method for polymerizing the liquid crystalline polymer in the pellets of the present invention is not particularly limited. For example, the method for producing the liquid crystalline polyester and / or the liquid crystalline polyesteramide is produced according to the known polycondensation method of polyester or polyesteramide. it can.

For example, in the production of the above-mentioned preferably used liquid crystalline polyester, the following production method is preferably exemplified.

(1) p-acetoxybenzoic acid, 4,4 '
-Diacylated aromatic dihydroxy compounds such as diacetoxybiphenyl and diacetoxybenzene and aromatic dicarboxylic acids such as terephthalic acid and polyester polymers such as polyethylene terephthalate, oligomers or aromatic dicarboxylic acids such as bis (β-hydroxyethyl) terephthalate Bis (β-hydroxyethyl)
A method for producing from ester by decondensation polycondensation reaction.

(2) p-hydroxybenzoic acid, 4,4 '
-Aromatic dihydroxy compounds such as dihydroxybiphenyl and hydroquinone, aromatic dicarboxylic acids such as acetic anhydride and terephthalic acid, polyester polymers such as polyethylene terephthalate, oligomers or bis (β
A method for producing a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid such as -hydroxyethyl) terephthalate by a deacetic acid polycondensation reaction.

(3) A method of using 1,2-bis (4-hydroxybenzoyl) ethane as a part of the starting material in the production method of (1) or (2) as described in JP-A-3-59024.

As the catalyst used in the polycondensation reaction, those known as polycondensation catalysts for liquid crystalline resins can be used.

The melt viscosity of the liquid crystalline resin pellets of the present invention is preferably 1 to 2000 Pa · s, preferably 2 to 10
More preferably, it is 00 Pa · s.

The melt viscosity is the melting point (Tm) +1.
It is a value measured by a Koka type flow tester using a nozzle having a nozzle diameter of 0.5 mm and a nozzle length of 10 mm under a condition of a shear rate of 1,000 (1 / sec) at a temperature of 0 ° C. Further, the melting point (Tm) is Tm1 after the observation of the endothermic peak temperature (Tm1) observed when the polymerized polymer is measured at a temperature rising condition from room temperature to 40 ° C./min in the differential calorimetry.
After being held at a temperature of + 20 ° C for 5 minutes, the temperature was once cooled to room temperature under the temperature lowering condition of 20 ° C / min, and then measured again under the temperature rising condition of 20 ° C / min, the endothermic peak temperature (Tm2
) Indicates the peak.

The liquid crystalline resin used in the present invention may further contain a filler. The filler is not particularly limited as long as it can be contained in the liquid crystalline resin, and examples thereof include one or more fillers selected from inorganic and / or organic fillers, additives, and other thermoplastic resins. .

The blending amount of the filler is not particularly limited, but 0.01 to 200 parts by weight, preferably 0.1 to 150 parts by weight of the filler is added to 100 parts by weight of the liquid crystalline polymer.
Parts by weight may be included. In order not to impair the excellent moldability and mechanical properties of the liquid crystalline polymer, the filling amount of the inorganic and / or organic filler is preferably 40 to 150 parts by weight, more preferably 50 to 100 parts by weight. The filling amount of the additive is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight or less.
The filling amount of the thermoplastic resin is preferably 0.01 to 150 parts by weight, more preferably 0.1 to 100 parts by weight.

As the inorganic and / or organic filler, glass fiber, carbon fiber, aromatic polyamide fiber, potassium titanate fiber, aluminum borate fiber, gypsum fiber,
Brass fiber, stainless fiber, steel fiber, ceramic fiber, boron whisker fiber, asbestos fiber, graphite, mica, talc, wet or dry silica, colloidal silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, straw Examples thereof include fibrous, powdery, granular or plate-like inorganic and / or organic fillers such as stenite, titanium oxide, molybdenum disulfide, calcium phosphate, barium sulfate, alumina and zirconia. The average fiber diameter of the glass fibers used in the present invention is preferably 3 to 15 μm.
Further, the glass fiber is preferably treated with a coating or sizing agent such as an epoxy type, urethane type or acrylic type, and an epoxy type is particularly preferable. Further, the inorganic filler is preferably treated with a surface treatment agent, and an epoxysilane or aminosilane coupling agent is particularly preferable.

As additives, antioxidants and heat stabilizers (for example, hindered phenol, hydroquinone, phosphites and their substitution products), ultraviolet absorbers (for example, resorcinol, benzophenone, etc.),
Examples include conventional additives such as colorants including dyes (eg, nigrosine) and pigments (eg, cadmium sulfide, phthalocyanine, carbon black), plasticizers, antistatic agents, flame retardants and the like.

Examples of the thermoplastic resin include olefin resins such as polypropylene, polyethylene and polystyrene, polyethylene terephthalate, polybutylene terephthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyesters such as polyarylate, polyamide and polycarbonate. , Polyacetal,
Usual thermoplastic resins such as polyarylene sulfide such as polyphenylene sulfide, polyether ether ketone, polyether imide, polyamide imide, polyether sulfone, polysulfone, polyoxymethylene and the like can be mentioned.

The feature of the pellet of the present invention is that the value of σ / W is 0.2 or less when the average weight per pellet is W (mg) and its standard deviation is σ (mg). , Preferably 0.18 or less, more preferably 0.16
Hereafter, it is most preferably 0.14 or less. If the value of σ / W is larger than 0.2, the feedability during extrusion or molding,
Quantitative properties deteriorate and the object of the present invention cannot be achieved. Also, the average weight W per pellet is 5 to 1
00 mg is preferable and 10 to 50 mg is more preferable. Here, the average weight per pellet is W (mg), and the standard deviation σ (mg) is obtained by measuring about 400 pellets one by one using a balance having an accuracy of 0.1 mg or more. It should be noted that a plurality of pellets connected by fusion or the like (continuous ball) is counted as one pellet.

The production method for obtaining the pellets made of the above liquid crystalline resin is not particularly limited as long as the pellets defined in the present invention can be obtained. For example, a liquid crystal containing a liquid crystalline polymer is used. A method of cutting a string-like material made of a functional resin with a cutter having a movable blade having a small clearance and a fixed blade can be mentioned. After the polymerization of the liquid crystalline polymer is completed, such a string-like material is obtained by discharging a liquid crystalline resin containing a liquid crystalline polymer in a molten state from the polymerization reaction tank in a string shape, or a liquid crystalline resin in a molten state into a string shape from an extruder. It is used by a method such as discharging. More specifically, the liquid crystalline polymer in a molten state after completion of the polymerization was discharged from the reaction can through the mouthpiece, or the liquid crystalline resin in the molten state was discharged from the extruder through a die into a string shape and was discharged. A method of cutting the string-like material into pellets with a cutter having a small clearance, or melt-kneading the liquid crystalline polymer and the filler using a melt-kneader such as an extruder, and then discharging them in a string-like shape through a die. However, it is recommended that the discharged string-like material be cut into pellets with a cutter having a small clearance.

When the liquid crystalline polymer and the filler are melt-kneaded, it is preferable to use a twin-screw extruder. Above all, a melt-kneading method in which the liquid crystalline polymer and the filler are supplied all at once or successively to the extruder is recommended.

The step of cutting the string-like material made of the liquid crystalline resin is not particularly limited, but the string-like material obtained by discharging the molten liquid crystalline resin in a string shape from the die or die is cooled by cooling water. After that, a method of cutting with a cutter after passing through an air layer such as an air layer, a method of cooling the string-like material with cooling water and then cutting with a cutter in the presence of cooling water, and the like can be mentioned. The temperature of these cooling water is 10 ~ 90
C is preferable, and 20 to 70 C is preferable. The diameter of the discharge port is preferably 1 to 10 mm, more preferably 2 to 7 mm.

When cutting the string-like material discharged through the die or die into pellets, it is usually cut by a cutter having a movable blade and a fixed blade to form pellets. The blade clearance is
For example, it is preferably 0.01 mm or more and 0.09 mm or less.
It is more preferably 0.015 mm or more and 0.07 mm or less, still more preferably 0.02 mm or more and 0.05 mm or less, and a moving blade using a rotating blade is preferably used. If the clearance is too large, the whiskers and the like of the pellets will be large, and the pellet shape will tend to be poor. If it is too small, the fixed blade and the moving blade may come into contact during cutting.
Further, the fixed blade and the movable blade are preferably made of a material such as zirconia, stellite (an alloy in which chromium and tungsten are added to cobalt as a base), or tungsten carbide.

Since the pellets of the present invention thus obtained are excellent in feedability and quantitativeness, they can be stably molded in molding such as injection molding and extrusion molding. For example, in molding such as injection molding, there is no variation between shots, and stable molding is possible, so variation in quality (for example, dimensional accuracy) of the molded article is small, and a highly reliable molded article is obtained. The molded products thus obtained are various gears, various cases, sensors, LED lamps, connectors, sockets, resistors, relay case switch 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, FDD carriages, FDD chassis, HDD parts,
Electric / electronic parts such as motor brush holder, parabolic antenna, computer related parts, etc .;
VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio / laser disks / compact disks, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts. Various bearings such as household, office electrical product parts, office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, oilless bearings, stern bearings, underwater bearings, etc. Mechanical parts such as motor parts, lighters and typewriters, optical devices such as microscopes, binoculars, cameras and watches, precision machine parts, alternator terminals, alternator connectors, IC regulators, potentiometers for light deer. Me Tabesu, various valves such as exhaust gas valve, fuel related-exhaust system, an intake system various pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint,
Carburetor main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, air conditioner thermostat base, heating hot air Flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, debut butter, starter switch, starter relay, transmission wire harness, window washer nozzle, air conditioner panel switch board, fuel related electromagnetic Valve coil, fuse connector, horn terminal, electrical component insulating plate, step Motor rotor, lamp socket, lamp reflector, lamp housing,
It is useful for automobile / vehicle related parts such as brake piston, solenoid bobbin, engine oil filter, ignition device case, and other various applications.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples.

EXAMPLE 1 20.1 kg of p-hydroxybenzoic acid, 2.8 kg of 4,4'-dihydroxybiphenyl, 2.5 kg of terephthalic acid and an intrinsic viscosity were placed in a 0.1 m3 reaction vessel equipped with a stirring blade and a distillation tube. Of about 0.6 dl / g polyethylene terephthalate
4.8 kg of acetic anhydride and 21.7 kg of acetic anhydride were charged and reacted under stirring in a nitrogen gas atmosphere at 150 ° C. for 2 hours, then heated to 250 ° C. in 2.5 hours and further held for 1 hour at 320 ° C. The temperature was raised to 1.5 hours. Then 1.
The pressure was reduced to 1.0 mmHg in 5 hours, and the reaction was continued for 1 hour to complete polycondensation. Next, pressurize the inside of the reaction vessel to 2.0 kg / cm2, and use the die with 5 circular discharge ports with a diameter of 5 mm for 3
Strand cutter with 20 ° C polymer discharged at a rate of 40m / min in a string shape, passed through a water bath with a water temperature of 40 ° C for 2 seconds, and the clearance between the rotary blade and fixed blade was adjusted to 0.04mm through the air layer. (Tanabe Plastic Machinery Co., Ltd.) pelletized to a length of 3 mm. The melting point of this liquid crystal polyester resin was 315 ° C. Table 1 shows the results of the average weight, standard deviation, σ / W, pellet shape and weighing stability of the pellets. The measuring method is as follows.

(1) Average weight (W) of pellets and standard deviation (σ): The weight of 400 pellets was measured with a precision precision balance made by METTLER to a unit of 0.1 mg, and the average weight (W) was calculated. The standard deviation (σ) was calculated.

(2) Shape of pellets: The pellets were visually inspected and the presence or absence of whiskers or cracks in the pellets was observed.

(3) Weighing stability It was used for an injection molding machine (Sumitomo Nestal injection molding machine Promat (Sumitomo Heavy Industries, Ltd.)) in which the cylinder temperature was 320 ° C. and the mold temperature was 90 ° C., and the thickness was 2 mm × 70 mm. A 70 mm square plate was molded for 50 shots, and the average value of the shot measuring times and the standard deviation thereof were measured.

Example 2 As in Example 1, polycondensation of liquid crystalline polyester was completed, the pressure in the reaction vessel was increased to 2.0 kg / cm ^2, and the solution was passed through a die having 5 circular discharge ports with a diameter of 5 mm. The polymer at 320 ℃ is discharged at a take-off speed of 100m / min, cooling water at 50 ℃ is flowed, and in the presence of the cooling water, the clearance between the rotary blade and the fixed blade is adjusted to 0.03mm, and the length is 3mm.
Pelletized to the size of. The melting point of this liquid crystal polyester resin was 315 ° C. The average weight of this pellet,
The results of standard deviation, σ / W, pellet shape and metric stability are shown in Table 1.

Comparative Example 1 As Example 1 except that a strand cutter in which the clearance between the rotary blade and the fixed blade was adjusted to 0.10 mm was used after completing the polycondensation reaction under the same composition and under the same conditions as in Example 1. Pelletized under the same conditions. The results are shown in Table 1.

Comparative Example 2 Same as Example 2 except that after the polycondensation reaction was completed under the same composition and under the same conditions as in Example 2, a cutter in which the clearance between the rotary blade and the fixed blade was adjusted to 0.10 mm was used. Pelletized on condition. The results are shown in Table 1.

Example 3 2 with a screw diameter of 44 mm equipped with an in-cylinder pressure reducing device
100 parts by weight of liquid crystal polyester obtained in the same manner as in Example 1 in a shaft extruder (manufactured by Japan Steel Works, Ltd.) and a diameter of 13 μm
50 parts by weight of glass fiber having a length of m and a length of 3 mm and 2 parts by weight of carbon black are continuously supplied at a total of 50 kg / hour, a cylinder temperature of 310 ° C., and a screw tachometer 20.
After melt-kneading under the condition of 0 rpm, the molten polymer at 330 ° C was discharged in a string shape at a linear velocity of 20 m / min through a die having 7 circular discharge ports of 5 mm in diameter arranged horizontally, and a water bath at a water temperature of 50 ° C was used. After passing through it for 1.8 seconds, it was pelletized to a size of 3 mm in length with a strand cutter in which the clearance between the rotary blade and the fixed blade was adjusted to 0.04 mm through the air layer. The average weight of the pellets, standard deviation, σ of this pellet
The results of / W, pellet shape and metric stability are shown in Table 1.

Comparative Example 3 After melt-kneading under the same composition and under the same conditions as in Example 3, pelletizing was performed under the same conditions as in Example 3 except that a strand cutter in which the clearance between the rotary blade and the fixed blade was adjusted to 0.10 mm was used. did. The results are shown in Table 1.

[0048]

[Table 1] As is clear from Table 1, the pellets of the present invention are superior to the comparative examples in metering stability.

[0049]

INDUSTRIAL APPLICABILITY The present invention makes it possible to obtain pellets of a liquid crystalline resin or a liquid crystalline resin composition which are excellent in supply and quantitative properties.

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Claims (8)

(57) [Claims] 1. A pellet comprising a liquid crystalline resin containing a liquid crystalline polymer, wherein the average weight per pellet is W (mg) and its standard deviation is σ (mg), the value of σ / W. Is 0.2 or less. 2. A pellet according to claim 1, wherein the liquid crystal resin and further comprises a filler 0.01 to 200 parts by weight per 100 parts by weight of a liquid crystalline polymer. 3. A liquid crystalline polymer comprising the following structural units (I) and (I
I), (III) and (IV) Tona is, structural units (I) and (I
The sum of (I) corresponds to the sum of structural units (I), (II) and (III).
30 to 95 mol%, structural unit (III) is structural unit (I)
, (II) and (III) in total, 70 to 5 mol%
And the molar ratio [(I) / (II)] of the structural units (I) and (II) is 75 /
25 to 95/5, and the structural unit (IV) and the structural unit (II)
And claim 1 sum is substantially equimolar (III) or
Or the pellet according to item 2 . [Chemical 1] (However, R ₁ in the formula is It represents one or more groups selected from, R ₂ is ## STR3 ## And one or more groups selected from However, in the formula, X represents a hydrogen atom or a chlorine atom. ) 4. A method for producing pellets, wherein a string-like material made of a liquid crystalline resin containing a liquid crystalline polymer is cut by a cutter having a moving blade and a fixed blade, and the clearance between the moving blade and the fixed blade of the cutter is A method for producing a pellet, which is not less than 0.01 mm and not more than 0.09 mm. 5. A cord-like material, after completion of polymerization of a liquid crystalline polymer,
A liquid crystalline resin containing a liquid crystalline polymer in a molten state is discharged in a string form from a polymerization reaction tank, or a liquid crystalline resin in a molten state is discharged in a string form from an extruder.
4. The method for producing a pellet according to 4 . 6. The method for producing pellets according to claim 5, wherein the string-like material made of a liquid crystalline resin is cooled with cooling water and then cut with a cutter in the presence of cooling water. 7. The method of claim 4-6 method of manufacturing a pellet according to any one of the preceding, wherein the moving blade of the cutter is a rotating blade. 8. claims 4-7 method of manufacturing a pellet according to any one of the preceding, wherein the clearance of the moving blade and the fixed blade of the cutter is less than 0.07mm or 0.015 mm.