JPH10180753A - Manufacture of liquid crystal resin pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain liquid crystal resin pellets, which have such shape that improved feed performance and volumetric characteristics can be provided, at high yield. SOLUTION: In a manufacture of pellets, in which liquid crystal resin in a molten state is delivered, in the form of string, into a trough in which cooling water fed from a nozzle flows, cooled, solidified, and cut in the presence of cooling water, the trough is inclined with respect to the horizontal line at an angle larger than 0 degree and not exceeding 30 degrees and the trough is set so that the height of the trough near the delivery point of the resin is made larger than the height of the trough near a cutter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing pellets of liquid crystalline resin. More specifically, the present invention relates to a production method for obtaining liquid crystal resin pellets having a shape excellent in supply and quantitative properties at a high yield.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for higher performance of plastics, and a number of polymers having various new properties have been developed. Among them, optically anisotropic liquid crystals characterized by parallel alignment of molecular chains. Attention has been paid to the fact that water-soluble resins have excellent fluidity and mechanical properties.

On the other hand, as a method for producing thermoplastic resin pellets, a method in which a molten polymer is extruded into a string shape through a die provided at a discharge outlet, cooled through a water bath, solidified, and cut into pellets is used. (Cold cut method) is most commonly used. Further, in order to further improve the yield of pellets in the above method, there is a method in which a molten polymer is flowed in a trough in a trough and cut in the presence of cooling water.

However, the liquid crystalline resin has a lower melt viscosity than other thermoplastic resins, and the solidified liquid crystalline resin string has a rigid and tough fiber. Then, the cross section of the string is not constant,
Curved or cracked pellets when cutting,
The pellets become irregular in shape due to the mixing of debris and powder, and the pelletization yield deteriorates.In addition, the obtained pellets are formed at the raw material input port of the extruder or molding machine, that is, when the supply amount varies. It turns out that troubles are more likely to occur.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to obtain a liquid crystal resin pellet having a shape excellent in supply and quantitative properties at a high yield.

[0006]

That is, the present invention provides (1) discharging a liquid crystalline resin in a molten state as a string into a trough in which cooling water is flown through a discharge device, and cooling the string. A method for producing pellets that is solidified and cut in the presence of cooling water, wherein the trough angle is greater than 0 degrees and 30 degrees or less with respect to a horizontal axis, and the trough height near the discharge portion is a cutter. A method for producing a liquid crystalline resin pellet, wherein the trough is installed so as to be higher than a nearby trough height, (2) the method in which the liquid crystalline resin contains a p-hydroxybenzoic acid residue as an essential component ( (1) The method for producing a liquid crystalline resin pellet, (3) The above (1), (2) wherein the liquid crystalline resin contains an ethylenedioxy unit as an essential component.
A method for producing a liquid crystalline resin pellet according to any one of the above,
(4) The method for producing a liquid crystalline resin pellet according to any one of the above (1) to (3), wherein the liquid crystalline resin comprises the following structural units (I), (II), (III) and (IV):

Embedded image (However, R ₁ in the formula is

Embedded image R ₂ represents one or more groups selected from

Embedded image And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom.

(5) The liquid crystalline resin is composed of the above structural units (I) and (I)
(I), (III) and (IV), and the structural units (I) and (I)
The total of I) is 30 to 95 mol% based on the total of structural units (I), (II) and (III), and the structural unit (III) is the structural unit (I)
, (II) and (III) in an amount of 70 to 5 mol%, and the molar ratio of the structural units (I) and (II) [(I) / (II)] is 75%.
/ 25 to 95/5, and the structural unit (IV) is the structural unit (II)
(1) which is substantially equimolar to the sum of
(4) The method for producing a liquid crystalline resin pellet according to any one of (1) to (4), wherein the trough has a length of 1 to 3 m.
(5) The method for producing a liquid crystalline resin pellet according to any one of (1) to (5), wherein (7) the cooling water temperature is from 10 to 90 ° C. The liquid crystal according to any one of the above (1) to (7), wherein the method for producing a liquid crystalline resin pellet and (8) the melt viscosity of the liquid crystalline resin at a melting point + 10 ° C. is 2 to 50 Pa · s. This is a method for producing a conductive resin pellet.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid crystalline resin of the present invention is a resin capable of forming anisotropy when melted.
Examples thereof include liquid crystal polyester amide, liquid crystal polyester carbonate, and liquid crystal polyester elastomer. Among them, liquid crystal polyester and liquid crystal polyester amide are preferably used.

As the above-mentioned liquid crystalline polyester, a polyester forming an anisotropic molten phase comprising a structural unit selected from aromatic oxycarbonyl units, aromatic dioxy units, aromatic dicarbonyl units, ethylenedioxy units and the like can be used. Examples of the liquid crystalline polyester amide include a polyester amide forming an anisotropic molten phase comprising the above structural unit and a structural unit selected from an aromatic iminocarbonyl unit, an aromatic diimino unit, an aromatic iminooxy unit, and the like. Can be mentioned.

The liquid crystalline resin which can be preferably used in the present invention is a liquid crystalline resin containing a structural unit comprising p-hydroxybenzoic acid as an aromatic oxycarbonyl unit.
Liquid crystalline resins containing an ethylenedioxy unit as an essential component can also be preferably used. More preferably, the following structural unit (I)
, (III), (IV) or (I), (II), (III), (IV) is a polyester comprising a structural unit, most preferably (I), (II), (III), (III) It is a polyester comprising the structural unit of IV).

[0011]

Embedded image (However, R ₁ in the formula is

Embedded image R ₂ represents one or more groups selected from

Embedded image Represents one or more groups selected from In the formula, X represents a hydrogen atom or a chlorine atom. It is preferable that the structural unit (IV) and the total of the structural units (II) and (III) are substantially equimolar.

The structural unit (I) is a structural unit generated 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 generated 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 generated from ethylene glycol, The 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, Structural units formed from aromatic dicarboxylic acids selected from -bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and 4,4'-diphenyletherdicarboxylic acid are shown below. Of these, R ₁

Embedded image And R ₂ is

Embedded image Is particularly preferred.

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

That is, the structural units (I), (III) and (I
In the case of the 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 to 80 mol% is more preferable. Also,
It is preferable that the structural unit (IV) is substantially equimolar to the structural unit (III).

On the other hand, the structural units (I), (II), (III),
In the case of the copolymer comprising (IV), the total of the above structural units (I) and (II) is preferably 30 to 90 mol% based on the total of the structural units (I), (II) and (III). , 40 to 85 mol% is more preferred. The structural unit (III) is the structural unit
It is preferably from 70 to 10 mol%, more preferably from 60 to 15 mol%, based on the total of (I), (II) and (III). The molar ratio [(I) / (II)] between the structural units (I) and (II) is preferably 75/25 to 95/5, more preferably 7/25.
8/22 to 93/7. Further, it is preferable that the structural unit (IV) is substantially equimolar to the sum of the structural units (II) and (III).

Further, as the liquid crystalline polyesteramide,
Polyesteramides forming an anisotropic molten phase containing p-iminophenoxy units formed from p-aminophenol in addition to the structural units (I) to (IV) are preferred.

The liquid crystalline polyesters and liquid crystalline polyesteramides which can be preferably used include, in addition to the components constituting the structural units (I) to (IV), 3,3'-diphenyldicarboxylic acid and 2,2'-diphenyl Aromatic dicarboxylic acids such as dicarboxylic acid, 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'-dihydroxydiphenylsulfone, 4,4'- Dihydroxydiphenyl sulfide,
Aromatic diols such as 4,4'-dihydroxybenzophenone, aliphatics such as 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; Further copolymerization of an alicyclic diol, an aromatic hydroxycarboxylic acid such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, p-aminophenol, p-aminobenzoic acid and the like within a range that does not impair the liquid crystallinity. I can do it.

The method for polymerizing the liquid crystalline resin in the liquid crystalline resin pellets of the present invention is not particularly limited. For example, the method for producing a liquid crystalline polyester and / or a liquid crystalline polyester amide may be a known polyester or polyester amide polycondensation method. It can be manufactured according to it.

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

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

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

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

Such a polycondensation reaction is usually carried out in a polymerization reaction vessel, and the liquid crystalline resin after the polymerization is melted out of the reaction vessel through a discharge device such as a nozzle (or a base) in a molten state. Is discharged.

In the present invention, the string-like material discharged from the discharge device is discharged as a string-like material into a trough in which cooling water is flown, and the liquid crystalline resin is cooled and solidified, and cut in the presence of the cooling water. When forming pellets, the trough angle is greater than 0 degrees and less than or equal to 30 degrees with respect to the horizontal axis, and the trough height near the discharge section is higher than the trough height near the cutter. Is installed.

The term "trough angle" as used herein refers to an angle at which the trough is inclined with respect to the horizontal axis. When the trough is formed of a single plane, the angle formed by the plane is formed of two or more planes. In this case, it refers to the average angle. In the present invention, it is essential that the trough angle is larger than 0 degree and 30 degrees or less, but it is preferably 2 degrees or more and 20 degrees or less, and more preferably 5 degrees or more and 15 degrees or less. If the trough angle exceeds 30 degrees, good string cannot be obtained because the string is curved or meandering, and the diameter of the string is uneven. Further, the length of the trough is preferably 1 to 3 m, more preferably 1.5 to 2.5 m. The temperature of the cooling water is preferably from 10 to 90C, more preferably from 20 to 60C. Further, the diameter of the discharge port is preferably 1 to 10 mm, and preferably 2 to 7 mm.
Is more preferred.

Further, the take-up speed of the cord is 50 to 40.
It is preferably 0 m / min, more preferably 75 to 300 m / min.

Preferably, the cutting is performed in water.

FIG. 1 is an example of a process chart for explaining a method for producing a pellet which is preferably used when pelletizing a liquid crystalline resin after polymerization in the present invention.

After the liquid crystalline resin is polymerized in the reaction vessel (only the main part is partially illustrated), the liquid crystalline resin still in a molten state is discharged as a string 3 from the reaction vessel base 2. Is done. The string 3 is a trough 7 into which the cooling water 5 is poured.
Through the cooling water discharged into the trough 7 and flowing through the trough 7, while being cooled, it is turned into a cutter comprising a cord-like material take-up roll 8, a cord-like material cutting fixed blade 9, and a cord-like material cutting rotary blade 10. After being conveyed and taken up by the cord-like material take-up roll 8, it is cut in water by a cord-like material cutting fixed blade 9 and a cord-like material cutting rotary blade 10, and a pellet 11 is obtained. The cut pellets 11 are conveyed to the pellet receiving tank 12 by cooling water flowing into the pellet receiving tank 12 from the trough via the cutter portion. After a while
It is subjected to a draining step (not shown). Although not always necessary, a string-shaped object cooling spray may be provided above the trough in order to sufficiently cool the conveyed object.

The drained pellets are dried in a usual manner to be subjected to the next step such as production or molding of the composition. The drained pellets are conveyed while being dried by means of air blowing or the like. Can be used for the next step.

The melt viscosity of the liquid crystalline resin pellet of the present invention is preferably 1 to 2000 Pa · s, and 2 to 1000 Pa · s.
S is more preferable, but the melt viscosity is 2 to 50 Pa
・ The time of s is more effective.

Here, the melt viscosity is the melting point (Tm) +1.
This 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 the conditions of 0 ° C. and a shear rate of 1,000 (1 / second). The melting point (Tm) refers to the endothermic peak temperature (Tm1) observed when the polymerized polymer is measured from room temperature under a heating condition of 40 ° C./min.
After holding at a temperature of + 20 ° C. for 5 minutes, once cooling to room temperature at a temperature lowering condition of 20 ° C./min, and then measuring again at a temperature rising condition of 20 ° C./min, an endothermic peak temperature (Tm 2)
) Peak.

The liquid crystalline resin pellets produced in the present invention include glass fiber, carbon fiber, aromatic polyamide fiber, potassium titanate fiber, aluminum borate fiber, gypsum fiber, brass fiber, stainless steel 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, wollastenite, titanium oxide, molybdenum disulfide, calcium phosphate, barium sulfate, alumina, zirconia, etc. Reinforcing agents such as inorganic fillers, antioxidants, heat stabilizers, flame retardants, ultraviolet absorbers,
By adding ordinary additives such as a lubricant, a release agent, a dye, and a pigment, and other thermoplastic resins, predetermined characteristics can be imparted.

As a method for adding these, it is preferable to melt-knead the liquid crystalline resin pellets and other components, and a known method can be used for the melt-kneading. For example, the composition can be melt-kneaded at a temperature of 200 to 400 ° C. using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, or the like to obtain a composition.

Further, since the liquid crystalline resin pellets produced in the present invention are excellent in supplyability and quantitativeness, it is possible to produce molded articles by subjecting them to molding such as injection molding efficiently and stably. The composition can be produced stably and efficiently even when supplied to a melt kneader such as a component and a twin screw extruder, and molded products obtained therefrom are various gears, various cases, sensors, LED lamps, Connectors, sockets, resistors, relay case switch coil bobbins, capacitors, variable condenser cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases , Power module, housing, semiconductor, liquid crystal display parts, FDD carriage, DD chassis, HDD parts,
Electrical and electronic components such as motor brush holders, parabolic antennas, and computer-related components;
VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio / laser discs / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts Various bearings such as home and office electrical products parts, office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, oilless bearings, stern bearings, underwater bearings, etc. Machine parts such as motor parts, lighters, typewriters, etc., optical equipment such as microscopes, binoculars, cameras, clocks, etc., precision machine parts, alternator terminals, alternator connectors, IC regulators, potentiometers for light drier 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, dust distributor, starter switch, starter relay, transmission wiring harness, window washer nozzle, air conditioner panel switch board, fuel-related electromagnetics Valve coil, fuse connector, horn terminal, electrical component insulation plate, step Motor rotor, lamp socket, lamp reflector, lamp housing,
It is useful for automotive and vehicle related parts such as brake piston, solenoid bobbin, engine oil filter, ignition device case, and other various uses.

[0037]

The present invention will be described in more detail with reference to the following examples.

Example 1 20.1 kg of p-hydroxybenzoic acid, 2.8 kg of 4,4'-dihydroxybiphenyl, 2.5 kg of terephthalic acid were placed in a 0.1 m ³ reaction vessel equipped with a stirring blade and a distilling tube. Polyethylene terephthalate having a viscosity of about 0.6 dl / g
4.8 kg and 21.7 kg of acetic anhydride were charged and reacted at 150 ° C. for 2 hours with stirring under a nitrogen gas atmosphere. Then, the temperature was raised to 250 ° C. in 2.5 hours, and after holding for 1 hour, further 320 ° C. Until 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 the polycondensation. Then, the inside of the reaction vessel was pressurized to 2.0 kg / cm ² , and a polymer having a temperature of 320 ° C. was taken through a base having five circular discharge ports having a diameter of 4 mm at a rate of 100 m / min. It is higher than the trough height near the cutter, and is discharged in the form of a string into a trough with a trough angle of 10 degrees and a trough length of 2 m, flowing cooling water at 50 ° C. It was pelletized to a size of 2 mm and a length of 3 mm. This liquid crystal polyester resin has a melting point of 315 ° C. and a melt viscosity of 25 Pa · s at 325 ° C.
Met. Table 1 shows the results of the running properties of the string, the bulk density of the pellets, the pelletization yield, and the pellet shape. In addition, each measuring method is described below.

(1) Running property of the string-like object The state of the string-like object in the trough was visually observed.

(2) Bulk Density of Pellets Measurement was performed according to JIS K 6911.

(3) Pelletization Yield The ratio (%) of the yield of pellets excluding pellets of non-standard size to the amount of polymer discharged from the discharge port was determined.

(4) Pellet Shape The pellets were visually observed, and the presence of beards and pellets in the pellets was observed.

Examples 2 to 6, Comparative Examples 1 and 2 A liquid crystal polyester resin was polymerized in the same manner as in Example 1;
Pelletizing was performed under the conditions shown in (1). Table 1 shows the results.

[0044]

[Table 1] As is clear from Table 1, the liquid crystalline resin pellets obtained by the production method of the present invention have a higher yield and uniform shape than the pellets obtained by the method shown in the comparative example.

[0045]

According to the production method of the present invention, liquid crystalline resin pellets having a shape excellent in supply property and quantitative property can be obtained in high yield.

[Brief description of the drawings]

FIG. 1 is an example of a process diagram illustrating a method for producing a pellet in the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 reaction vessel (part) 2 mouthpiece of reaction vessel 3 string 3 cooling water supply line 5 cooling water 6 string cooling spray 7 trough 8 string pulling roll 9 string cutting fixed blade 10 string cutting rotation Blade 11 Pellet 12 Pellet receiving tank

Claims (8)

[Claims] 1. A pellet that discharges a liquid crystalline resin in a molten state as a string into a trough into which cooling water has flowed through a discharge device, cools and solidifies the string, and cuts it in the presence of the cooling water. Wherein the trough angle is greater than 0 ° and 30 ° or less with respect to the horizontal axis, and the trough height near the discharge section is higher than the trough height near the cutter. A method for producing liquid crystalline resin pellets, comprising: 2. The method for producing a liquid crystalline resin pellet according to claim 1, wherein the liquid crystalline resin contains a p-hydroxybenzoic acid residue as an essential component. 3. The method for producing a liquid crystalline resin pellet according to claim 1, wherein the liquid crystalline resin contains an ethylenedioxy unit as an essential component. 4. A liquid crystalline resin comprising the following structural units (I), (II) and (I)
The method for producing a liquid crystalline resin pellet according to any one of claims 1 to 3, comprising (II) and (IV). Embedded image (Where R ₁ in the formula is And R ₂ represents one or more groups selected from And at least one group selected from In the formula, X represents a hydrogen atom or a chlorine atom. 5. A liquid crystalline resin comprising the above structural units (I), (II) and (I)
II) and (IV), the sum of structural units (I) and (II) being 3 with respect to the sum of structural units (I), (II) and (III)
0 to 95 mol%, the structural unit (III) is composed of the structural units (I) and (II)
And (III), the molar ratio of the structural units (I) and (II) [(I) / (II)] is 75/25 to
95/5, and the structural unit (IV) is composed of the structural units (II) and (I
The method for producing a liquid crystalline resin pellet according to any one of claims 1 to 4, which is substantially equimolar to the total of (II). 6. A trough having a length of 1 to 3 m.
5. A method for producing a liquid crystalline resin pellet according to any one of the above items 5. 7. The method for producing liquid crystalline resin pellets according to claim 1, wherein the cooling water temperature is 10 to 90 ° C. 8. A liquid crystalline resin having a melting viscosity at the melting point + 10 ° C. of 2
The method for producing a liquid crystalline resin pellet according to any one of claims 1 to 7, wherein the pressure is 50 Pa · s.