JPH06192403A - Method of continuous batch polymerization of liquid crystalline polyester - Google Patents

Abstract

PURPOSE:To improve the yield of pellets of a liq. crystalline polyester which contains little contaminants and does not clog a nozzle. CONSTITUTION:A liq. crystalline polyester is produced by continuous batch polymn. wherein a liq. crystalline polyester is formed by soln. polymn. in a polymn. vessel equipped with a feed charge or liq. transporting port, a polymerizate discharge port, a stirrer, and a jacket, and the resulting polymer melt is discharged, while the next batch of feedstock is fed to the vessel to repeat the polymn. The polymn. is carried out under such a condition that the polymer melt is discharged from the vessel until the amt. of melt remaining reaches 30kg per m<3> or lower of the internal vol. of the vessel before the next batch is fed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a batch continuous polymerization process for obtaining high quality liquid crystalline polyester.

[0002]

2. Description of the Related Art In recent years, the demand for higher performance of plastics has increased, and many polymers having various new functions have been developed and put on the market. Among them, optics characterized by parallel arrangement of molecular chains Anisotropic liquid crystalline polyester has been attracting attention because of its excellent fluidity and mechanical properties.

A batch continuous polymerization method is known as a method for producing a large amount of liquid crystalline polyester.

In this method, for example, in the case of a deacetic acid polycondensation reaction, two reaction containers, a reaction can and a polymerization can, are allowed to communicate with each other, and the first liquid crystalline polyester material is acetylated in the reaction can. After the reaction, the reaction product is transferred to a polymerization vessel to start the polymerization. Then, the second time the liquid crystalline polyester raw material is charged into the empty reaction can to carry out a reaction mainly based on acetylation. Next, the first liquid crystalline polyester which has completed the polymerization in the polymerization container is discharged from the discharge port of the polymerization container. After the discharge from the polymerization container is completed, the second reaction product in which the reaction mainly composed of acetylation is completed is transferred from the reaction container to the polymerization container. Thus, batch polymerization is continuously carried out by an extrusion method.

[0005]

However, since the polymerization in the batch type continuous polymerization method is a so-called temperature rising polymerization in which the reaction is initially performed at a low temperature and gradually at a high temperature, after completion of one batch, after discharging the polymer, It is necessary to cool the temperature in the can in order to start the polymerization of the batch.

In the liquid crystalline polyester obtained by the conventional batch type continuous polymerization method, the residual polymer of the previous batch was highly crystallized at the time of cooling and at the time of heating, and this was often mixed as a foreign substance. .

An object of the present invention is to provide a batch type continuous polymerization method for obtaining a high quality liquid crystalline polyester free from the inclusion of foreign matter.

[0008]

That is, according to the present invention, liquid crystalline polyester is melt-polymerized in a polymerization can having a raw material charging port or liquid transfer port, a polymer discharging port, a stirrer and a jacket, and a molten polymer is discharged. After that, in the batch type continuous polymerization method in which the next raw material is charged into the same polymerization vessel and polymerization is repeated, when the polymer is discharged, the residual polymer amount is set to 30 kg or less per 1 m ³ of the internal volume of the polymerization vessel, and then the next The present invention provides a batch type continuous polymerization method for a liquid crystalline polyester, which comprises charging raw materials.

The residual polymer amount in the present invention is obtained by subtracting the actually obtained polymer amount from the theoretical polymer amount obtained from the charged amount.

The batch type continuous polymerization in the present invention means that the polymerization is carried out in a reaction vessel for a predetermined period of time and the polymer is discharged.
It also refers to a polymerization method in which the following raw materials are transferred to the reaction vessel and polymerization is repeated.

The number of reaction vessels may be one or more, but at least one vessel (polymerization can) is equipped with a raw material inlet or liquid transfer port, a polymer outlet, a stirrer and a jacket. is there.

As a process for producing the liquid crystalline polyester, for example, deacetic acid polycondensation reaction may be carried out by carrying out the reaction and polymerization mainly in acetylation in one container, or in the first container. It is also possible to carry out a reaction mainly involving acetylation, transfer the reaction product to a polymerization vessel through a liquid transfer port, and carry out polymerization in the polymerization vessel.

The rotating direction of the stirrer is preferably such that the contents are scraped down by the stirrer. In the scraping direction, the polymer adheres to the upper part of the stirring blade and the upper part of the can wall to increase the residual polymer, which is not preferable.

The polymerization can and the stirring blade may have any shape as long as they are used in ordinary polyester polymerization, but a helical blade is preferable in the sense that the polymer remaining in the can is reduced.

The liquid crystalline polyester obtained by the present invention has a melt anisotropy among polyesters composed of units selected from aromatic oxycarboxylate units, aromatic dioxy units, aromatic dicarbonyl units, ethylenedioxy units and the like. Polyester shown, preferably the following structural unit (I), (II), (IV) or (I), (III), (IV) or (I), (II), (III), (IV) Is a liquid crystalline polyester comprising the structural unit of
(I), (III), (IV) or (I), (II), (III), (IV)
It is a liquid crystalline polyester consisting of.

[0016]

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

[Chemical 5] R ₁ represents one or more groups selected from

[Chemical 6] Represents one or more groups selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (III)] and the structural unit (IV) are substantially equimolar).

The structural unit (I) is a polyester structural unit produced 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, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,2-
Bis (4-hydroxyphenyl) propane and 4,4
A structural unit produced from an aromatic dihydroxy compound selected from ′ -dihydroxydiphenyl ether, a structural unit (III) is a structural unit produced from ethylene glycol, and a structural unit (IV) is terephthalic acid, isophthalic acid, 4,
4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,
Each of the structural units formed from an aromatic dicarboxylic acid selected from 4'-dicarboxylic acid, 1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylic acid and diphenyl ether dicarboxylic acid is shown. Of these, in the case of a copolymer composed of the structural units (I), (II), (III) and (IV), R ₁ is

[Chemical 7] Is 70% by mole or more of the structural unit (II), and R ₂ is

[Chemical 8] Particularly preferably those having 70 mol% or more of the structural unit (IV).

Further, in the case of a copolymer comprising the above structural units (I), (III) and (IV), R ₂ is

[Chemical 9] Are particularly preferred.

In the case of a copolymer comprising the above structural units (I), (II) and (IV), R ₁ is

[Chemical 10] And / or

[Chemical 11] R ₂ is

[Chemical 12] And / or

[Chemical 13] Are particularly preferred.

The above structural units (I), (II), (III) and (I
The copolymerization amount of V) is arbitrary. However, from the viewpoint of fluidity, the following copolymerization amount is preferable.

That is, the above structural units (I), (III) and (I
In the case of a copolymer comprising V), the structural unit (I) is preferably 30 to 95 mol% of [(I) + (III)],
˜95 mol% is more preferred. Further, the structural unit (IV) is substantially equimolar to the structural unit (III).

In the case of a copolymer comprising the above structural units (I), (II), (III) and (IV), the above structural units [(I) + (II)]
Is preferably 60 to 95 mol% of [(I) + (II) + (III)], and more preferably 82 to 92 mol%. Also, the structural unit
(III) is preferably 40 to 5 mol% of [(I) + (II) + (III)], and more preferably 18 to 8 mol%. The molar ratio of structural unit (I) / (II) is preferably 75/25 to 95/5, more preferably 78/22 to 93/7 from the viewpoint of the balance between heat resistance and fluidity. Also, the structural unit (I
V) is substantially equimolar to the structural unit [(II) + (III)].

In the case of a copolymer comprising the above structural units (I), (II) and (IV), the structural unit (I) is 40 to 90 of [(I) + (II)] from the viewpoint of fluidity. It is preferably mol%, particularly preferably 60 to 88 mol%, and the structural unit (IV) is substantially equimolar to the structural unit (II).

When the above-mentioned liquid crystalline polyester which can be preferably used in the present invention is polycondensed, the above structural unit (I) is used.
To an aromatic dicarboxylic acid such as 3,3′-diphenyldicarboxylic acid or 2,2′-diphenyldicarboxylic acid, or an aliphatic compound such as adipic acid, azelaic acid, sebacic acid or dodecanedioic acid Alicyclic dicarboxylic acids such as dicarboxylic acid and hexahydroterephthalic acid, chlorohydroquinone, methylhydroquinone, 4,4 '
-Aromatic diols such as dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide and 4,4'-dihydroxybenzophenone, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexane Aliphatic and alicyclic diols such as diols and 1,4-cyclohexanedimethanol and aromatic hydroxycarboxylic acids such as m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and p-
Aminophenol, p-aminobenzoic acid and the like can be further copolymerized in a small proportion within a range not impairing the object of the present invention.

There is no particular limitation on the reaction mechanistic production method of the liquid crystalline polyester in the present invention, and it can be produced according to the known polycondensation method of the liquid crystalline polyester.

For example, in the production of the above-mentioned preferably used liquid crystalline polyester, the production method of (1) and (2) when the structural unit (III) is not contained, and (3) when the structural unit (III) is contained. Are preferred.

(1) p-acetoxybenzoic acid, 4,4 '
A method for producing a diacylated aromatic dihydroxy compound such as diacetoxybiphenyl or diacetoxybenzene and an aromatic dicarboxylic acid such as terephthalic acid by a deacetic acid polycondensation reaction.

(2) p-hydroxybenzoic acid, 4,4 '
A method in which an aromatic dihydroxy compound such as dihydroxybiphenyl or hydroquinone or an aromatic dicarboxylic acid such as terephthalic acid is reacted with acetic anhydride to acylate a phenolic hydroxyl group, and then a deacetic acid polycondensation reaction is used for production.

(3) In the presence of a polyester polymer such as polyethylene terephthalate, an oligomer, or a bis (β-hydroxyethyl) ester of an aromatic dicarboxylic acid such as bis (β-hydroxyethyl) terephthalate, (1) or ( The method of manufacturing by the method of 2).

Although these polycondensation reactions proceed without a catalyst, it is sometimes preferable to add a metal compound such as stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, or metal magnesium. .

In the present invention, it is important to discharge the liquid crystalline polyester thus obtained so that the residual polymer is 30 kg or less, preferably 25 kg or less per 1 m ³ of the inner volume of the polymerization can. If there is a part of the contents to be discharged that has a low temperature and is not in a sufficiently molten state, that part will not be discharged and will become a residual polymer, so the entire contents will be in a sufficiently molten state. Need to be For this purpose, the temperature inside the polymerization vessel is set to [melting point (Tm) -5 ° C] described later.
1.5 hours or more, preferably 2 hours or more and /
Alternatively, it is preferable to carry out the polymerization under a polymerization condition of Tm or more for 0.3 hour or more, preferably 0.5 hour or more.

Polymer remaining in the can is ³ per 1 m ^{3 of the} inner volume of the polymerization can.
If the amount is more than 0 kg, the bottom polymer has a high melting point at the time of cooling or during the next polymerization, and the high melting point substance is mixed as foreign matter in the next batch of polymerized polymer, clogging the mouthpiece of the discharge port, The physical properties become poor.

The melt viscosity of the above-mentioned liquid crystalline polyester which can be preferably used in the present invention can be measured in logarithmic viscosity in pentafluorophenol, and in that case, at a concentration of 0.1 g / dl at 60 ° C. 0.3 in measured value
The above is preferable, and particularly when the above structural unit (III) is included, 0.5 to 3.0 dl / g is preferable, and the above structural unit (II
When I) is not included, 2.0 to 10.0 dl / g is preferable.

The liquid crystalline polyester in the present invention is preferably 10 to 20,000 poise, and more preferably 20 to 1 poise.
More preferably 10,000 poise.

The melt viscosity is the melting point (Tm) +10.
It is a value measured by a Koka type flow tester under conditions of a shear rate of 1,000 (1 / sec) under conditions of ° C.

Here, the melting point (Tm) is the endothermic peak temperature (T) observed in the differential calorimetric measurement when the polymerized polymer is measured at a temperature rising condition from room temperature to 20 ° C./min.
After observing m ₁ ), the temperature was maintained at Tm ₁ + 20 ° C. for 5 minutes, then cooled once 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. is the point to the endothermic peak temperature (Tm _2).

[0037]

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

[0038] Example 1 vertical and horizontal reactor which ratio the scraping-down direction of the helical ribbon blade into the polymerization apparatus having an inner volume of 0.1 m ³ of 2.5 is provided with a stirrer fitted to a height of 0.035 m ³ Was polymerized as follows using a polymerization can for polycondensation.

22.1 p-hydroxybenzoic acid was added to the reaction can.
kg, 4,4'-dihydroxybiphenyl 2.8 kg,
Charge 4.8 kg of polyethylene terephthalate, 2.5 kg of terephthalic acid and 21.7 kg of acetic anhydride, and
The reaction is carried out at 0 to 250 ° C. for 5 hours, then the reaction product is transferred to a polymerization vessel, and the temperature inside the vessel is 250 to 315 over 2 hours.
℃, depressurize the polymerization can to 1.0 Torr, 315 ℃
The stirring was continued for 2 hours to complete polycondensation. Thereafter, the inside of the polymerization vessel was pressurized to 4 kg / cm ² , and then the polymer was discharged in a strand shape through the die. The remaining polymer at this time is 1.8.
kg (18 kg per 1 m ^{3 of the} inner volume of the polymerization vessel) The pelletization yield was 93%.

The theoretical structural formula of the obtained liquid crystalline polyester is as follows.

[0041]

[Chemical 14] k / l / m / n = 80 / 7.5 / 12.5 / 20 This liquid crystalline polyester is manufactured by DS manufactured by Perkin Elmer.
The melting point (Tm ₁ ) of the C-7 type was measured at a temperature of 20 ° C./minute from room temperature and the melting point (Tm ₁ ) was 316 ° C.

After the discharge of the polymer was completed, water was poured into the jacket of the polymerization vessel to cool the temperature inside the vessel to 250 ° C., and immediately the reaction product of the next batch reacted in the reaction vessel under the same conditions as above was polymerized. The solution was transferred to a can and polymerized under the same conditions. After the polymerization, the mixture was discharged to obtain liquid crystalline polyester with a pelletization yield of 93%.

Example 2 and Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except for the polymerization temperature, using a reaction vessel and a polymerization vessel. The polymerization temperature in Example 2 was 315 ° C. or higher for 1.5 hours. In No. 1, liquid crystalline polyester having the same composition as in Example 1 was discharged at 315 ° C. or higher for 0.1 hour. The amount of residual polymer at that time is as shown in Table 1.
Then, the second batch was polymerized, discharged and pelletized in the same manner as in Example 1 to obtain a liquid crystalline polyester. Table 1 shows the amount of bottom polymer in the first batch of these liquid crystalline polyesters and the pelletization yield of the second batch.

Comparative Example 2 A polymer polymerized in the same manner as in Example 1 was polymerized at a pressure of 1 k.
After pressurizing to g / cm ² , liquid crystalline polyester having the same composition as in Example 1 was discharged. The amount of residual polymer at that time is as shown in Table 1. Then, the second batch was polymerized, discharged and pelletized in the same manner as in Example 1 to obtain a liquid crystalline polyester. The pelletizing yield is shown in Table 1.

[0045]

[Table 1] It can be seen that when the residual polymer amount in the first batch is more than 30 kg per 1 m ³ of the inner volume of the polymerization can, the high melting point polymer causes clogging of the die at the time of discharging the liquid crystalline polyester in the second batch, and the pelletization yield decreases. .

[0046]

Industrial Applicability According to the present invention, the polymerized molten polymer is discharged so that the residual polymer amount is 30 kg or less per 1 m ³ of the internal volume of the polymerization container, and then the next raw material is charged. As a result, the pelletization yield is improved because no foreign matter is mixed in due to the formation.

Claims (3)

[Claims] 1. A liquid crystal polyester is melt-polymerized in a polymerization container having a raw material charging port or liquid transfer port, a polymer discharging port, a stirrer and a jacket, and a molten polymer is discharged, and then the next raw material is the same polymerization container. In a batch-type continuous polymerization method in which the polymer is discharged into the reactor, the residual polymer is reduced to 30 kg or less per 1 m ³ of the inner volume of the polymerization container when the polymer is discharged, and then the next raw material is charged. Batch continuous polymerization of water-soluble polyester. 2. The liquid crystalline polyester according to claim 1, wherein the liquid crystalline polyester is (I), (II), (IV) or (I), (III), (IV) or (I), (II), (III) below. The batch-type continuous polymerization method for a liquid crystalline polyester according to claim 1, which comprises the structural unit of (IV). [Chemical 1] (However, R ₁ in the formula is R ₁ represents one or more groups selected from Represents one or more groups selected from In the formula, X represents a hydrogen atom or a chlorine atom, and the structural unit [(II) + (III)] and the structural unit (IV) are substantially equimolar). 3. The liquid crystalline polyester according to claim 1, wherein the liquid crystalline polyester is (I), (II), (IV) or (I), (II), (III), (I).
The batch type continuous polymerization method of a liquid crystalline polyester according to claim 1, which comprises a structural unit of V).