JPH0625255B2 - Wholly aromatic polyester amide - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel melt-moldable wholly aromatic polyesteramide which forms an optically anisotropic melt phase.

[Conventional technology]

In recent years, the demand for higher performance of organic polymer materials is increasing, and the appearance of fibers, films, molded products, etc. having excellent mechanical performance such as tensile strength and elastic modulus and thermal performance such as heat resistance is strongly emerging. Is desired.

As a polymer material satisfying the above requirements, a so-called thermotropic liquid crystal polymer, which is mainly composed of a rigid structure such as an aromatic ring as a main skeleton and forms an optically anisotropic molten phase, has been attracting attention in recent years. I am collecting. In the liquid crystal state,
Since the molecules are highly aligned, liquid crystal polymers provide highly oriented fibers, films and molded articles with excellent mechanical properties. Further, this thermotropic liquid crystal polymer is also of interest because it can be melt-polymerized and melt-molded. Of the thermotropic liquid crystal polymers, the thermotropic liquid crystal polyester has been given a great deal of attention, and thermotropic liquid crystal polyesters having a large number of structures have already been proposed.

A typical example of such a polymer mainly comprises a divalent phenol derivative and an aromatic dicarboxylic acid derivative (Japanese Patent Publication No. 55-482, JP-A No. 53-6542).
No. 1, gazette of Japanese Patent Publication No. 55-500173, etc.), mainly 4-hydroxybenzoic acid or 6-
A compound comprising an aromatic hydroxy acid derivative such as hydroxy-2-naphthoic acid (JP-A-54-77691, JP-A-55-144024, JP-A-56-1052)
No. 6, etc.) and the like.

Not only thermotropic liquid crystal polyesters, but also thermotropic liquid crystal polyesteramides in which an amide bond is partially introduced in addition to the ester bond have been proposed.
It is said that introduction of a part of amide bonds into ester bonds improves adhesiveness, fatigue resistance, lateral strength and the like (see Japanese Patent Laid-Open No. 172921/1982). Such thermotropic liquid crystal polyester amides may be other than a 6-hydroxy-2-naphthoic acid derivative, an aromatic aminocarboxylic acid derivative such as p-aminobenzoic acid, and optionally a naphthalene skeleton such as p-hydroxybenzoic acid. A compound comprising a hydroxycarboxylic acid derivative having an aromatic ring (see JP-A-57-177020), a 6-hydroxy-2-naphthoic acid derivative, a symmetrical aromatic dicarboxylic acid such as terephthalic acid, p-aminophenol or p. -Aromatic hydroxyamino compounds or aromatic diamino compound derivatives such as phenylenediamine and optionally aromatic dihydroxy compound derivatives (see JP-A-57-172921), the above-mentioned JP-A-57-172921. In addition to the composition of Japanese Patent Publication Such as those consisting of a hydroxycarboxylic acid derivative having an aromatic ring other than a naphthalene skeleton (see JP-A-57-177019) have been proposed, such as carboxymethyl benzoic acid.

[Problems to be solved by the invention]

The present inventor has investigated thermotropic liquid crystal polyester amides that support high-performance fibers, films, molded articles, and the like. As a result, a polymer containing a 6-hydroxy-2-naphthoic acid derivative as a copolymerization component has a melting point (more It was confirmed that the material has a low solid-to-liquid crystal transition temperature) and has good workability. However, it has been found that the molded articles in a broad sense obtained from the thermotropic liquid crystal polyesteramide having a 6-oxy-2-naphthoyl skeleton, which has been conventionally proposed, such as fibers, have some problems. That is, the wholly aromatic polyester amide comprising a 6-hydroxy-2-naphthoic acid derivative, an aromatic aminocarboxylic acid derivative and optionally an aromatic hydroxycarboxylic acid derivative disclosed in JP-A-57-177020 is homogeneous. Poor property, with a polarizing microscope equipped with a heating device to be described later, when observing a molten state, an optically anisotropic region and a partially isotropic region may exist in a mixed state, Polyesteramide is inferior in moldability, and when fibers are to be obtained by, for example, melt spinning, yarn breakage occurs frequently and it is difficult to wind it at high speed. On the other hand, the wholly aromatic polyester amide comprising a 6-hydroxy-2-naphthoic acid derivative, an aromatic dicarboxylic acid and an aromatic hydroxyamine or diamine derivative disclosed in JP-A-57-172921 is
The above-mentioned uniformity is very excellent, and the molding processability is also good, but the molded product, for example, the fiber lacks thermal stability, and when it is held at high temperature for a long time, its mechanical performance such as rupture occurs. It was found that the strength tends to decrease.

[Means for solving problems]

The present inventors have completed the present invention as a result of synthesizing a polyester amide having various compositions and a thermotropic liquid crystal polyester amide which does not have the above-mentioned drawbacks and conducted extensive studies. According to the invention, essentially the following repeating units I, II, III, IV and optionally V and composition (provided that the units II and IV are present in substantially equimolar amounts
And the total amount of units V are present in the range of 40-80 mol%)
Becomes (In the formula, X, Y, and Z each represent a divalent linearly oriented aromatic residue containing one or more aromatic rings which are the same or different from each other.) Pentafluorophenol, concentration of 0.1% by weight / volume, 60 ° C. A melt-moldable wholly aromatic polyester amide having an inherent viscosity of 0.1 to 10 dl / g as measured by 1. and forming an optically anisotropic melt phase at a temperature of 400 ° C. or less is provided.

The polyesteramide of the present invention can be produced by using an aromatic carboxylic acid compound and a lower alkyl ester or amide of an aromatic hydroxy compound or an aromatic aminocarboxylic acid compound as a starting material, and a hydroxyl group or an amino group in advance in a lower level. A metal compound selected from the group consisting of compounds of Group IV and Group V metals of the periodic table from alkyl carboxylic acid compounds, aromatic hydroxy compounds and aromatic aminocarboxylic acid compounds without amidation It has the feature that it can be produced by direct melt polymerization in the presence of a catalytic amount.

Unit I can be referred to as the 6-oxy-2-naphthoyl moiety and is present in the polymer in an amount in the range of 40-80 mol%, preferably 50-75 mol%. X in unit II is 1
It is a divalent linearly oriented aromatic residue containing one or more aromatic rings, and the unit II is present in the polymer in an amount within the range of 5 to 30 mol%. The linear orientation means that two bonds are symmetric with respect to the aromatic ring. Representative examples of X include a 1,4-phenylene group, a 2,6-naphthalene group, and a 4,4'-diphenyl group, but a 1,4-phenylene group is preferable. Unit III is capable of forming an amide bond in the polymer and is in an amount within the range of 5 to 30 mol% in the polymer. Y of the unit III has the same definition as that of X of the unit II and examples of the same kind are exemplified, but a 1,4-phenylene group is preferable. Unit IV is
It is present in the polymer in an amount in the range of 5 to 30 mol%. unit
Z of IV has the same definition as that of X of unit I, and the same kind of Z can be exemplified, but it is preferably a 1,4-phenylene group.

In the present invention, in addition to the above essential components I to IV, a moiety represented by the unit V, which should be called a 4-oxybenzoyl moiety, can coexist. When the unit V is coexisted, it is present in an amount of 40 mol% or less and the total amount of the unit I and the unit V is in the range of 40 to 80 mol%. Since the 4-hydroxybenzoic acid derivative is cheaper than the 6-hydroxy-2-naphthoic acid derivative, the cost of the polymer produced by the coexistence of the unit V can be reduced. Unit II and unit
Each raw material compound is used under the condition that IV is substantially equimolar, and the total amount of units I to V is usually substantially 10
Although it is 0, other units may be contained within a range not impairing the object and effect of the present invention. The presence of the units II and IV is important, and when the units II and IV are each less than 5 mol%, the homogeneity of the produced polymer is poor and, as a result, the melt moldability is also poor.

In each aromatic ring constituting a part of the units I to V described above, at least a part of hydrogen atoms bonded to the aromatic ring is an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, It may be substituted with a halogen or a phenyl group. However, in the usual case, it is desirable that the ring substituent is not present because the crystallinity of the produced polymer is high and the physical properties of the molded article obtained from the polymer are excellent.

The polyesteramide of the present invention is required to have a logarithmic viscosity of 1.0 to 10 dl / g when measured in pentafluorophenol at a concentration of 0.1% by weight / volume and 60 ° C.
When the logarithmic viscosity is less than 1.0 dl / g, the molding processability is poor and the mechanical properties of the obtained molded product are insufficient. The polyesteramide of the present invention preferably has a logarithmic viscosity of 10 dl / g or less, preferably 6 dl / g or less from the viewpoint of moldability. The logarithmic viscosity (ηinh) is calculated by the following equation.

Here, c is the concentration (weight / volume%) of the polymer solution, and ηrel is the relative viscosity, which is obtained from the ratio of the flowing time of the polymer solution and the solvent in the capillary viscometer.

The polyesteramide of the present invention is required to exhibit an optically anisotropic molten phase at a temperature of 400 ° C. or lower. The optical anisotropy can be confirmed by transmitting light when the molten state of the polymer is observed under a crossed Nicols using a polarizing microscope equipped with a heating device for a microscope.

The polyesteramide of the present invention can be produced by the following two methods. First, the first method is a method of producing by transesterification. In this method, the hydroxyl group and the amino group are converted into a lower alkyl ester and a lower alkylamide in advance, and then the compound is condensed with a compound having a carboxyl group to proceed with the polymerization. For example, 6-acetoxy-2-naphthoic acid as a preferable raw material compound giving units I to V,
Mention may be made of terephthalic acid, 4-acetamidobenzoic acid, hydroquinone diacetate and 4-acetoxybenzoic acid. Polymerization in this case is performed by ordinary melt polymerization. At the time of polymerization, about 0.001 to 1% by weight of the total weight of monomers used as raw materials, preferably about
When the known transesterification catalyst is used in an amount within the range of 0.005 to 0.5% by weight, favorable results are obtained in terms of polymerization rate. Specific examples of the transesterification catalyst include alkali metal salts or alkaline earth metal salts of carboxylic acids, alkyl tin oxides, diaryl tin oxides, alkyl stannic acids,
Examples thereof include titanium dioxide, alkoxytitanium silicate, titanium alcoside, Lewis acid such as BF ₃ , and hydrogen halide.

The second production method is a method in which a compound having a hydroxyl group or an amino group and a compound having a carboxyl group are directly polymerized in the presence of a specific catalyst.
In this method, a compound having a hydroxyl group and a compound having an amino group can be directly used as a starting material without using the lower alkyl ester and amide derivatives of the compound having a hydroxyl group and the compound having an amino group described above. Since there is no need to pre-esterify and amidate the starting compound,
This is industrially advantageous because it is not necessary to use a polymerization apparatus made of a corrosion resistant and expensive material. 6-hydroxy-2-naphthoic acid, terephthalic acid, and
Mention may be made of 4-aminobenzoic acid, hydroquinone and 4-hydroxybenzoic acid. The polymerization of this method is carried out in the presence of the following metal compound catalyst. The metal compound is a metal compound of Group IV and Group V of the periodic table, and examples thereof include antimony, titanium, tin or germanium salts and oxides. Representative examples include dibutyltin oxide, diphenyltin oxide, dibutyltin diacetate, dimethoxytin, titanium dioxide, tetrabutyl titanate, tetraisopropyl titanate, antimony dioxide, and germanium dioxide. The amount of catalyst used is
Usually, it is about 0.001 to 5% by weight, preferably 0.01 to 1.0% by weight, based on the total weight of the monomers used for the polymerization. According to the study of the present inventor, in the production of wholly aromatic polyester amide, an aromatic hydroxyamine compound or an aromatic diamine compound is used as a raw material compound that gives an amide bond, as in the method described in JP-A-57-172921. When a direct polymerization is attempted by using, the reaction mixture solidifies as the reaction progresses, melt polymerization cannot be performed, and a thermotropic liquid crystal polyesteramide cannot be obtained. Thus, it is possible to produce a wholly aromatic polyester amide having excellent homogeneity, processability, and physical properties by direct polymerization, without passing through hydroxy and amino isomers through their lower alkyl ester and amide isomers. What can be done is also one of the features of the present invention.

In any of the above methods, the polymerization is usually 200 ~ 400 ℃
It is carried out at a temperature in the range of, under an atmosphere of an inert gas such as nitrogen or argon, preferably under the flow of the gas under normal pressure or reduced pressure. Water or a lower carboxylic acid is distilled out according to the kind of the starting material compound. Therefore, the reaction temperature is raised stepwise and the degree of reduced pressure is adjusted according to the amount of this distillation and the viscosity of the polymer. Polymerization time is usually 1 to 1
It is within the range of 0 hours.

The polyesteramide of the present invention can be formed into fibers, films, molded articles, etc. by melt molding. The fiber, film or molded article is produced by ordinary melt extrusion at a temperature 5 ° C to 50 ° C higher than the melting point of the polyesteramide. When making a molded product, about 1-60
It is also possible to use by including a solid filler and / or a reinforcing material in a weight percentage.

The fiber obtained by melt-spinning the polyesteramide of the present invention is subjected to heat treatment to obtain its mechanical properties,
In particular, the tensile strength can be further improved. The heat treatment is carried out in an atmosphere of an inert gas such as nitrogen or argon, preferably under flow, or under reduced pressure, at a temperature not higher than the melting point of the polymer, in a state where tension is not applied to the fiber, for about 10 minutes to 100 hours. To do. As the heat treatment progresses, the molecular weight increases and the melting point rises. The heat treatment temperature is preferably relatively low at first, for example, from 200 to 250 ° C. and increased stepwise or continuously. It is preferable to perform heat treatment at a temperature at which the fibers do not stick to each other and at a temperature as high as possible, because the desired mechanical properties can be achieved in a short time. The fibers thus obtained can be advantageously used for tire cords, hoses, belts, ropes, resin reinforcing materials and the like. The film obtained from the polyesteramide of the present invention is used as a packaging material, a base film for magnetic tape, a flexible base film, an insulating film and the like.

〔Example〕

 Hereinafter, specific examples of the present invention will be described according to examples.

Example 1 A 3-neck flask with a content of 300 ml equipped with a stirrer, gas inlet, distillation head and condenser was charged with 6-acetoxy-2-.
Naphthoic acid 46.0 g (0.20 mol), terephthalic acid 5.533 g
(0.0333 mol), 4-acetamidobenzoic acid 11.921 g
(0.0666 mol), hydroquinone diacetate 6.460 g
(0.0333 mol) and 0.075 g of sodium acetate were charged. The flask is then evacuated by a vacuum pump, 3
After displacing with nitrogen once, it was immersed in a bath kept at 230 ° C. with a stream of dry nitrogen at a rate of about 3 / hour, and stirring was started after the contents of the flask melted and became an opaque slurry. . After 40 minutes, the temperature of the bath was raised to 250 ° C. and kept at the same temperature for 1 hour. By this time, a total of 13.5 ml of acetic acid had distilled off. Then, the temperature of the bath was raised to 280 ° C., kept at the same temperature for 1 hour, and then raised to 320 ° C. 3
When kept at 20 ° C for 40 minutes, by this time a total of 16.2 ml
Acetic acid was distilled off. As the temperature increased and the reaction time progressed, the contents of the flask became more viscous and became glossy when stirred. Then, the pressure inside the system was gradually reduced by a vacuum pump. First, after keeping for 10 minutes under the pressure of 15 mmHg, raise the temperature of the bath to 340 ° C, and 0.4 ~ 0.5m
The pressure was set to mHg. After maintaining this temperature and pressure for 30 minutes, dry nitrogen was introduced, the pressure was returned to normal pressure, and the polymer was separated from the flask wall while cooling under a nitrogen atmosphere. After cooling, break the flask, take out the polymer carefully so that glass fragments do not enter the polymer, cut it into minute pieces, and then in a Soxhlet extractor with an acetone-hexane (volume ratio 1: 1) mixed solution for 8 hours. After extraction, the product was vacuum dried at 130 ° C for 12 hours. The polymer thus obtained had a concentration of 0.1% in pentafluorophenol.
2.826d when measured at 60 ° C, concentration of weight / volume%
It showed a logarithmic viscosity of 1 / g. A minute piece of this polymer was heated in a TH-600 type hot stage manufactured by Linkam Co., Ltd. in a nitrogen atmosphere at a rate of 5 ° C./min and observed under a polarizing microscope and a crossed Nicol. It was confirmed that the polymer started to transmit light and the degree of transmission became larger at around 300 ° C, and that the polymer formed an optically anisotropic molten phase. The molten phase observed in this way was completely homogeneous.

The polymer thus obtained was melt spun into a single filament. That is, using a spinneret having a single nozzle with a diameter of 0.2 mm and a hole length of 1 mm, a temperature of 315 ° C.
The fibers were extruded into the atmosphere at an extrusion rate of g / min and wound at a rate of 450 m / min. After melting the polymer,
Degassing was sufficiently performed to avoid air inclusion in the molten polymer as much as possible. The fineness of the obtained fiber was 6.4 denier, and the strength and elongation at room temperature were measured by an Instron universal testing machine and the results were as follows.

Breaking strength 8.2 g / denier Elongation 1.2% Initial elastic modulus 600 g / denier This fiber was heat treated in a relaxed state at 270 ° C. for 1 hour and then at 285 ° C. for 8 hours under dry nitrogen flow. It came to show.

Breaking strength 24.1 g / denier Elongation 5.2% Initial elastic modulus 585 g / denier The fiber thus obtained is 150 at 270 in a nitrogen atmosphere.
After holding for a long time, the strength and the elongation hardly changed.

Example 2 A flask equipped with the same equipment as used in Example 1 was charged with 31.02 g (0.165 mol) of 6-hydroxy-2-naphthoic acid, 7.47 g (0.045 mol) of terephthalic acid and 6.1 aminoaminobenzoic acid.
65 g (0.045 mol), hydroquinone 4.95 g (0.045 mol) and tetra-n-butyl titanate as a catalyst.
I charged 1g. Then, after purging the system with nitrogen in the same manner as in Example 1, 280 ° C. for 1 hour, 300 ° C. for 30 minutes,
Each was kept at 320 ° C. for 30 minutes and then at 340 ° C. for 45 minutes. The time required to raise the temperature between the temperatures was about 10 minutes in each case. By this time, a total of 3.5 ml of water had distilled out of the system. In the latter half of the reaction, a small amount of white sublimate adhered to the upper part of the flask, so it was dropped into the flask and returned to the reaction. Then, the system was gradually evacuated by a vacuum pump. Immediately after the vacuum was started, foaming occurred but then disappeared. It was heated to 340 ° C. for 90 minutes under a pressure of 0.3-0.4 mmHg. After that, the reaction was stopped in the same manner as in Example 1, the contents were taken out, pulverized, washed and dried. The polymer thus obtained had an inherent viscosity of 3.132 dl /
and an optically anisotropic molten phase was formed at 290 ° C. or higher. The polymer was spun as in Example 1 at a spinning temperature of 320 and wound at a speed of 230 m / min. The physical properties of the obtained fiber are as follows.

Fineness 16.1 Denier breaking strength 7.2 g / denier elongation 1.1% Initial elastic modulus 520 g / denier Example 3 In Example 1, 6-acetoxy-2-naphthoic acid 27.6 g (0.12 mol) and terephthalic acid were used as reaction raw material compounds. 4.98 g (0.03 mol), 4-acetamidobenzoic acid 10.7
4 g (0.06 mol) and 4-acetoxybenzoic acid 10.8
Example 1 was repeated except that g (0.06 mol) was used. The polymer obtained had an inherent viscosity of 2.916 dl / g and formed an optically anisotropic molten phase at 286 ° C or higher.
This polymer was prepared in the same manner as in Example 1 except that the spinning temperature was 315 ° C.
The fiber obtained by spinning at 300 m / min and having the following physical properties.

Fineness 9.3 Denier breaking strength 8.1 g / denier elongation 1.2% Initial elastic modulus 535 g / denier Example 4 In Example 2, 6-hydroxy-2-naphthoic acid 36.66 g (0.195 mol) and terephthalic acid were used as reaction raw material compounds. 4.98 g (0.03 mol), 4-aminobenzoic acid 6.165 g
(0.045 mol) and hydroquinone 3.3 g (0.03 mol)
Example 2 was repeated except that 0.13 g of dibutyltin acetate was used as the catalyst. The logarithmic viscosity of the obtained polymer was 2.824 dl / g, and this polymer was 283 ° C.
As a result, a uniform optically anisotropic molten phase was formed.

Comparative Example 1 57.5 in a flask equipped with the same equipment used in Example 1.
(0.25 mol) 6-acetoxy-2-naphthoic acid, 21.0
g (0.126 mol) terephthalic acid, 24.5 g (0.127 mol) p-acetoxyacetanilide and 0.02 g sodium acetate were charged. After replacing the system with nitrogen, 250 ℃
For 45 minutes, 280 ° C. for 45 minutes, then 320 ° C. for 25 minutes with stirring. Then, the system was gradually evacuated by a vacuum pump, and the reaction was stopped at 320 to 340 ° C. for 30 minutes under a pressure of 0.2 mmHg. The polymer was taken out, pulverized, washed and dried in the same manner as in Example 1. This polymer had an inherent viscosity of 5.23 dl / g when measured at 60 ° C. in pentafluorophenol at a concentration of 0.1% weight / volume. The spinning temperature of this polymer is 360 ℃ and the winding speed is 100m /
I wound up in minutes. In addition, yarn breakage during spinning occurred quite frequently. The obtained fiber had the following physical properties.

Fineness 16.1 Denier Breaking strength 7.3 g / denier Elongation 1.4% Initial elastic modulus 560 g / denier Then, this fiber was placed under nitrogen gas flow at 270 ° C. for 1 hour, and then 2
After heat treatment at 85 ° C. for 8 hours, the following physical properties were exhibited.

Breaking strength 17.3 g / denier Elongation 4.3% Initial elastic modulus 540 g / denier This fiber was treated in the same manner as in Example 1 at 270 ° C. in a nitrogen atmosphere at 1 ° C.
After being kept for 50 hours, the breaking strength was reduced to 12.8 g / denier and the elongation was reduced to 3.2%.

Comparative Example 2 69.0 g (0.30 mol) of 6-acetoxy-2-naphthoic acid, 18.0 g (0.1 mol) of 4-acetamidobenzoic acid and 18.4-acetoxybenzoic acid were added to the flask used in Example 1.
0 g (0.1 mol) was charged. After replacing the system with nitrogen gas in the same manner as in Example 1, the mixture was stirred at 250 ° C. for 45 minutes for 280 minutes.
After heating at 30 ° C. for 30 minutes and 320 ° C. for 10 minutes, the system was gradually depressurized to a pressure of 0.4 mmHg, heated for 20 minutes, heated to 340 and kept for 10 minutes, and then the reaction was stopped. The polymer was taken out, pulverized, washed and dried in the same manner as in Example 1. The inherent viscosity of this polymer was 2.431 dl / g. Observation of the molten state of the polymer microscopic pieces with a polarizing microscope at a magnification of 100 times revealed that an optically anisotropic region and an optically isotropic region were mixed. Spinning was attempted for this polymer in the same manner as in Example 1, but the spinnability was inferior to that in Example 1, and yarn breakage frequently occurred.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY According to the present invention, a novel wholly aromatic fragrance which is suitable for a fiber, film or various molded products which forms an optically anisotropic uniform molten phase and has good melt moldability and excellent mechanical and thermal characteristics. Group polyesteramides are provided.

Claims (2)

[Claims] 1. Repeating units I, II, II essentially as follows:
I, IV and optionally V and composition (provided that unit II and unit IV
Are substantially equimolar, and the total amount of the units I and V is 40
Present in the range of ~ 80 mol%), (Wherein X, Y and Z represent two linearly oriented aromatic residues each containing one or more aromatic rings which are the same or different) in pentafluorophenol at a concentration of 0.1% by weight / volume at 60 ° C. A melt-moldable wholly aromatic polyester amide having a logarithmic viscosity of 1.0 to 10 dl / g when measured and forming an optically anisotropic melt phase at a temperature of 400 ° C. or lower. 2. The wholly aromatic polyester amide according to claim 1, wherein X in the unit II, Y in the unit III and Z in the unit IV are all 1,4-phenylene groups.