JPS6197326A - Production of liquid crystal polyster - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal polyester of excellent flexibility, by forming a specified liquid crystal polyester by melt polymerization and reacting the polyester in a molten state with phenylenebisoxazoline in an apparatus having functions of both mixing and extrusion. CONSTITUTION:A liquid crystal polyester comprising 24-64mol% repeating units of formula I, 38-18mol% repeating units of formula II (wherein R1 is a 4-20C alicyclic bivalent radical or the like) and 38-18mol% repeating units of formula III (wherein R2 is a 4-20C alicyclic bivalent radical or the like) and having a ratio of formula II to formula III of 1 is produced by melt polymerization. After completion of the polymerization, the polymer is withdrawn from the polymerization vessel and fed to an apparatus having functions of both extrusion and mixing and reacted, by mixing in a molten state, with 0.1-4wt%, based on the crystalline polyester, phenylenebisoxazoline of formula IV (wherein R3-R10 are each H or alkyl) to obtain the purpose liquid crystal polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing liquid crystalline polyester, and more specifically, the present invention relates to a method for producing liquid crystalline polyester. The present invention relates to a method for producing liquid crystalline polyester in which phenylenebisoxazoline is reacted using an apparatus.

J, Polym, Sci, Polym, Che
m, Bd, P2O43 (1976)-, J,
Since liquid crystalline polyesters forming anisotropic melts were first reported by Jackson et al.

Liquid crystalline polyester has attracted attention and numerous studies have been conducted. The liquid crystalline polyester reported by If, J. Jackson, et al. was a copolymer of polyethylene terephthalate and p-hydroxybenzoic acid. p-
Hydroxybenzoic acid is 24 to 65 mol% (however, 1 terephthalic acid residue and 1 ethylene glycol residue each)
Calculate the mole % by considering it as the constituent vehicle position. ), and exhibits the strongest anisotropy in the vicinity of about 48 mol %. As the melt becomes oriented under shear, its viscosity under shear decreases. The molded product extruded from the nozzle was highly oriented even without stretching, and exhibited a high 2-flexural modulus of 14 GPa.

JP-A-50-59525 and JP-A-55-145
No. 733 discloses reacting phenylenebisoxazoline with polyester. The former discloses that the terminal carboxylic acid, which is a factor in the thermal decomposition of polyester, is reacted with phenylenebisoxazoline, with the aim of simultaneously increasing the molecular weight. Furthermore, in the latter case, it is disclosed that when phenylenebisoxapurine is reacted with a polyester in which 50 mol% or more of all terminal groups are carboxyl groups, the effect of increasing the molecular weight is particularly large.

However, these publications do not disclose that phenylenebisoxazoline is produced by copolymerizing p-hydroxybenzoic acid by remelting the solidified chips after cooling and reacting with phenylenebisoxazoline. Polyester is easily decomposed.

If phenylenebisoxazoline is reacted after melt polymerization and before cooling and solidifying, the reactivity will be better than remelting the chips and reaction will be performed, suppressing two decompositions and producing a high quality liquid crystalline polyester with less coloration. Or energy saving and cost saving.

There is no mention of it being effective.

More than 10 years have passed since the report by W. J. Jackson et al., and no concrete industrial product has yet been produced. One of the big reasons for this is.

Although it has high elasticity, it is hard, brittle, and easily cracks when bent.The second problem is that liquid crystalline polyester copolymerized with p-hydroxybenzoic acid has a high melting temperature during polymerization. Therefore, there are problems in the polymerization reaction such as 1 decomposition occurs and polymerization does not proceed, 9 polymerization reaction is slow due to insufficient stirring due to high melt viscosity, and 9 polymerization becomes difficult to take out. For example, if polymerization is carried out at a low temperature to suppress 1 decomposition, the melt viscosity becomes too high, causing problems with stirring and removal, making it impossible to obtain a liquid crystalline polyester with a sufficient degree of polymerization.On the other hand, if polymerization is carried out at a high temperature Since decomposition occurs, decomposition and coloring occur, making it impossible to obtain high-quality liquid crystalline polyester.

The inventors of the present invention first investigated a method of imparting flexibility to solve problems in physical properties, and found that by reacting a specific amount of phenylenebisoxazoline to liquid crystalline polyester, it was possible to It has been found that flexibility is provided. However, since this reaction is accompanied by thickening, 1
When this reaction is carried out in a polymerizer, III
New problems arose, such as difficulty in stirring and taking out reactants. In addition, when the liquid crystalline polyester that has been cooled and turned into chips is remelted using an extruder and reacted with phenylenebisoxapurine, the liquid crystalline polyester copolymerized with p-hydroxybenzoic acid easily decomposes. Therefore, re-melting caused decomposition and problems of coloring and viscosity reduction remained.

The present inventors have earnestly pursued a method to solve not only the problems in the physical properties of liquid crystalline polyester copolymerized with p-hydroxybenzoic acid but also the problems in monopolymerization reaction. When a liquid crystalline polyester copolymerized with an acid is obtained by melt polymerization, the liquid crystalline polyester with a degree of polymerization that has fluidity is taken out in a molten state and reacted with phenylenebisoxazoline using a device that has extrusion and mixing capabilities. For example, liquid crystalline polyester with a sufficiently high molecular weight and flexibility can be obtained without any problems of decomposition, stirring, or discharge, and this method does not require a remelting process or a heat source, resulting in cost savings. The present invention was discovered based on the discovery that the present invention is also very superior from the viewpoint of energy saving.

That is, 1 the present invention comprises the following general formulas (1), (■) and (I
When a liquid crystalline polyester composed of a repeating medium of II) is obtained by melt polymerization.

(III) 0-Rz -0- (hereinafter referred to as diol residue) [However, here (I) is 24 to 64 mol%, [■] is 3
8 to 18 mol%, (■) 38 to 18 mol%.

And the ratio between (■) and (III) is l. In the formula, R value is an alicyclic divalent radical having 4 to 20 carbon atoms, and 1 to 40 carbon atoms.
is an aliphatic divalent radical having 6 to 12 carbon atoms or an aromatic divalent radical having 6 to 12 carbon atoms, and +Rt is an alicyclic divalent radical having 4 to 20 carbon atoms, an aliphatic 2+i1[i radical having 2 to 40 carbon atoms, or 6 to 12 aromatic 2 (i1!i radicals) After polymerization, the liquid crystalline polyester is removed from the polymerization reactor in a molten state, and an apparatus having the ability to extrude and mix while maintaining the molten state. Using the following general formula (T
The method for producing a liquid crystalline polyester is characterized in that 0.1 to 4% by weight of phenylenebisoxazoline represented by V) is mixed with the liquid crystalline polyester and reacted.

R6Rt [However, R3 to RIO represent a hydrogen atom or an alkyl group. ] The liquid crystalline polyester used as a starting material in the present invention contains 24 to 64 mol% of p-hydroxybenzoic acid residues.
, composed of 38 to 18 mol% of dicarboxylic acid residues and 38 to 18 mol% of diol residues (however, the ratio of dicarboxylic acid residues to diol residues is 1).

If the p-hydroxybenzoic acid residue is outside the range of 24 to 64 mol %, liquid crystallinity is not exhibited. In the general formula of the dicarboxylic acid residue, R1 is an alicyclic radical having 4 to 20 carbon atoms, an aliphatic divalent radical having 1 to 40 carbon atoms, or examples thereof include malonic acid, succinic acid, and glutaric acid.

Adipic acid, pimelic acid, acelaic acid, sebacic acid,
Speric acid, 183-cyclopencune dicarboxylic acid, 1
．． 4-Cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid, Diphen M, 4.4'-methylene dibenzoic acid, diglycolic acid, thiodipropionic acid, 4.4
'-Sulfonyl dibenzoic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, dibenzoic acid, dimer acid, bis(p-carboxyphenyl)methane, p-oxy(p-carboxyphenyl)benzoic acid acid, ethylene-bis-p-benzoic acid, tetramethylene-bis(p-oxybenzoic acid M), 1,5-naphthalene dicarboxylic acid, and derivatives thereof such as alkylated products and halides.These are used alone. or 2
A mixture of more than one species may be used. Among these, preferred dicarboxylic acids are terephthalic acid and 2,6-naphthalene dicarboxylic acid. 80 mol% or more of the dicarboxylic acid is terephthalic acid or (and) 2,6-naphthalene dicarboxylic acid.

It is preferable to form a mixture in which the remaining 20 mol% or less is a different type of dicarboxylic acid because a liquid crystalline polyester with excellent physical properties can be obtained. On the other hand, in the general formula of the diol residue, R1
is an alicyclic group having 4 to 20 carbon atoms 2. Valence radical, carbon number 2~
40 aliphatic divalent radicals or aromatic divalent radicals having 6 to 12 carbon atoms. Specific examples of diols forming such diol residues include ethylene glycol, diethylene glycol, 1,2-propylene glycol, and 2-propylene glycol.
．． 4-dimethyl-2-ethylenehexane-1,3-diol.

2,2.4-1-dimethyl-1,3-bentanediol.

2.2-dimethyl-1,3-phytane'diol,
1,3-butanediol, 1,4-butanediol,
1,5-bentanediol, I,6-hexanediol.

1.4-Cyclohexanediol, hydroquinone.

resorcinol, 4,4'-sulfonyl difuninol.

Examples include derivatives such as 4.4-isopropylidenediphenol (commonly known as bisphenol A), 2.5-naphthalenediol, and alkylated products and halogenated products thereof.These may be used alone or in combination of two kinds. The above may be used as a mixture. Among these, preferred diols are ethylene glycol and hydroquinone. 80 mol% or more of the diol is ethylene glycol or (and) hydroquinone, and the remaining 20 mol%
A mixture containing diols of different types is preferred because a liquid crystalline polyester with excellent physical properties can be obtained.

The above liquid crystalline polyester is obtained by a melt polymerization method. For example, liquid crystalline polyester can be melt-polymerized using an acetylated heptamer, as in the synthesis of ordinary polyesters.

As disclosed in Japanese Patent Publication No. 56-18016.

A method in which a polyester previously obtained from only components excluding p-hydroxybenzoic acid and p-acetoxybenzoic acid are heated and melted under a stream of dry nitrogen, a copolymerized polyester fragment is generated by an acidolysis reaction, and then the pressure is reduced to increase the viscosity. However, it can be melt polymerized. Because it is easy to react.

I& person is preferred.

In the present invention, the liquid crystalline polyester obtained by melt polymerization is not solidified by cooling.

It is taken out in a molten state. For this reason, liquid crystalline polyester needs to have fluidity, specifically L
The intrinsic viscosity measured at 30° C. using a mixed solvent with a weight ratio of 1,2,2-tetrachloroethane/phenol of 50/50 is preferably 0.85 or less, particularly 0.75 or less. The extracted liquid crystalline polyester is passed through piping while in a molten state (a pump! J't may be involved at this time). Supplied to extruders, line mixers, etc. At this time, a device having an extrusion capacity 2 such as a gear pump, a screw set pump, and other various pumps and a device having a mixing capacity 2 such as various mixers, various blenders, and the above-mentioned devices having an extrusion capacity and a mixing capacity are combined. You may also use it. Here, a predetermined proportion of phenylenebisoxazoline is added in a solid (two particles, etc.) or in a molten state, and reacts by mixing. The reaction temperature is 320"C or less, especially 300" to avoid thermal decomposition of the resin.
It is preferable to carry out at C or less. The reaction time is preferably 60 to 300 seconds.

The phenylenebisoxazoline used in the present invention is represented by the general formula (■). Here R3
~RIQ is a hydrogen atom or an alkyl group, but it is preferable that all of R3 to R+c are hydrogen atoms because synthesis is easy. A preferred example of such a compound is 2,2'-p-phenylenebis(2-oxazoline).
2.2'-m-phenylenebis(2-oxazoline'), 2.2'-0-phenylenebis(2-
oxazoline), 2,2'-p-phenylenebis(
4-methyl-2-oxazoline), 2.2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2.2''-m-phenylenebis(4-methyl-2-
oxazoline).

Examples include 2'-m-phenylenebis(4,4'-dimethyl-2-oxazoline). The amount of phenylene bisoxaprine used is 0.1 per liquid crystalline polyester.
-4% by weight, preferably 1-3% by weight.

If it is less than 1% by 0.1i, there will be no substantial effect of reacting phenylene bisoxaprine, and if it exceeds 4% by weight, the plasticizing effect will be too large and the resulting polyester will lose its liquid crystallinity. .

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1. Comparative Examples 1 to 3 In an autoclave type polymerization machine of 50%, the intrinsic viscosity was 0.64.
52 moles of polyethylene terephthalate and 48 moles of p-hydroxybenzoic acid were charged and heated at 275°C under a stream of dry nitrogen.
The acidolysis reaction was allowed to proceed for 70 minutes. After that, the pressure of the system was gradually reduced to 0.3 mmHg.
The reduced pressure was maintained for 5 hours, and the intrinsic viscosity was 0.6.
5 (the molar ratio of p-hydroxybenzoic acid residue/terephthalic acid residue/ethylene glycol residue is 31.6/34.2/34.2) was obtained. (Comparative Example 1).

After that, nitrogen was introduced into the polymerization machine, the vacuum was broken and the pressure was slightly increased, and this liquid crystalline polyester was put into the polymerization machine in a molten state from the bottom of the polymerization machine. and was supplied at a constant rate through heat-insulating piping. At this time, 2.2'-m-phenylenebis(2-oxazoline) powder was added from Feedro at a constant ratio of 2% by weight based on the liquid crystalline polyester.

At this time, the rotation speed of the extreme leader is 150r, p, m
.

The temperature was 275° C.9 and the average residence time was 2 minutes. Although the viscosity increased with the reaction, one reactant was easily extruded from the die, and after cooling with water, it was easily formed into chips (Example 1). The polyester obtained here is shown in Table 1.
As shown in Figure 2, the physical properties have been improved compared to the polyester before the 2-reaction, such as a decrease in the Bayafugu ratio and an increase in the degree of insertion.

On the other hand, after the process of Comparative Example 1, nitrogen was introduced and the pressure was brought to normal pressure. Powder was added and reacted.

The viscosity increased rapidly after addition, and stirring became impossible after 1 minute.

After 4 minutes, I tried to take it out, but it was difficult to take it out from the bottom of the polymerization machine because the viscosity was so high that it practically did not flow (Comparative Example 2).

In addition, cooling the polyester obtained in the process of Comparative Example 1,
The polyester of Comparative Example 1 and 2,2'-m-phenylenebis(2-oxazoline) were reacted under the same conditions as in Example 1, except that the chipped product was supplied, and the reaction was as shown in Table 1. Although various properties are improved compared to the polyester obtained in Comparative Example 1, compared to the polyester obtained in Example 1, the 1 intrinsic viscosity is lower, the Young's modulus is higher, and the 1
Only a polyester with a low degree of insertion was obtained (Comparative Example 3).

In addition, the reaction was carried out under the same conditions as in Comparative Example 3 except that the residence time in the extruder was extended to 10 minutes.
The upper 1 degree insertion degree where coloring was observed was inferior to that of the polyester obtained in Example 1.

This shows that decomposition has already occurred (Comparative Example 4)
.

From the results of Comparative Examples 3 and 4, it seems that reacting after forming chips requires more steps and requires energy for drying and remelting the chips.

It can be seen that the reaction is not sufficiently carried out.

Examples 2-4. Comparative Examples 5 to 7 Terephthalic acid was added to an autoclave polymerizer at 50°C.
96 moles of A groups, 4 moles of isophthalic acid residues.

A copolymerized polyester with an intrinsic viscosity of 0.68 composed of 92 moles of ethylene glycol residues and 8 moles of 4.4''-isopropylidene diphenol residues was taken, and 100 moles of p-acetoxybenzoic acid was charged thereto. The temperature was then brought to 275° C. under a stream of dry nitrogen, and the acidolysis reaction was allowed to proceed for 70 minutes.Then, the system was gradually reduced in pressure, and finally the pressure was reduced to 0.3 mm and 11 g.

This reduced pressure was maintained for 7 hours, and the liquid crystalline polyester having an intrinsic viscosity of 0.67 (the molar ratio of p-hydroxybenzoic acid residues/dicarboxylic acid residues/diol residues was 33.3
/ 33.3/ 33.3) was obtained (Comparative Example 5
). Introduce nitrogen into the polymerization machine to break the vacuum.

After being slightly pressurized, this liquid crystalline polyester was fed in a molten state from the bottom of the polymerization machine to the feeder of a two-shaft extruder with a shaft diameter of 40 mm through a gear pump and heat insulation piping. At the same time as the supply, 2,2'-m-phenylenebis(2-oxazoline) was melted through a hole provided in the middle of the cylinder of the extruder using heat-retaining piping, and the polyester obtained in Comparative Example 5 was mixed with 1
．． When supplied at a concentration of 5 ft% and subjected to 2 reactions,
There were no handling problems (1) As shown in Table 2, a liquid crystalline polyester with excellent strength and elongation was obtained, which had a lower puffer ratio than the polyester before reaction (Example 2).

The rotation speed of the extruder at this time is 150 rpm, m
.

The temperature was 275°C and the average residence time was 2.5 minutes.

The amount of 2+2'-m-phenylenebis(2-oxazoline) added was 0.05% by weight (Comparative Example 6) and 0.5% by weight (
Example 3) One reaction was carried out in the same manner as in Example 2, except that the amounts were 2.5% by weight (Example 4) and 6% by weight (Comparative Example 7), and a polyester was obtained without any handling problems.

The polyester obtained in Comparative Example 6 had no improvement in physical properties compared to Comparative Example 5 because the amount of phenylenebisoxapurine added was too small.

On the other hand, in Comparative Example 7, the amount added was too large, so the liquid crystallinity was lost,
Also, the coloring is great.

The polyesters obtained in Examples 3 and 4 have an increased intrinsic viscosity and an improved degree of insertion as compared to the polyester of Comparative Example TE. It is also seen that the Young's modulus is reduced and flexibility is imparted.

According to the present invention, it has flexibility. Tough liquid crystalline polyester with a high degree of polymerization does not decompose or stir.

Can be obtained without any emission problems.

Claims (1)

[Claims] (1) When a liquid crystalline polyester composed of repeating units of the following general formulas (I), (II) and (III) is obtained by melt polymerization, (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II )▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III)-O-R_2-O- [However, (I) is 24 to 64 mol%, (II) is 38 to 18 mol%, and (III) is It is composed of 38 to 18 mol%, and the ratio of (II) to (III) is 1. In the formula, R_1 is an alicyclic divalent radical having 4 to 20 carbon atoms,
Aliphatic divalent radical having 1 to 40 carbon atoms or 6 to 1 carbon atoms
2 aromatic divalent radical, R_2 has 4 to 2 carbon atoms.
0 alicyclic divalent radical, an aliphatic divalent radical having 2 to 40 carbon atoms, or an aromatic divalent radical having 6 to 12 carbon atoms. ] After the polymerization is completed, the liquid crystalline polyester is taken out in a molten state from the polymerization reactor, and while maintaining the molten state, it is converted into the following general formula (I
A method for producing a liquid crystalline polyester, which comprises mixing 0.1 to 4% by weight of phenylenebisoxazoline represented by V) to the liquid crystalline polyester and reacting the mixture. (IV) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, R_3 to R_1_0 represent hydrogen atoms or alkyl groups. ]