JPS6291526A - Liquid crystal polyester - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal polyester excellent in heat resistance and flame retardancy, by reacting a (P-containing) aromatic diol with an aromatic dicarboxylic acid. CONSTITUTION:A P-containing aromatic diol (a) (e.g., formula I) is reacted with an aromatic dicarboxylic acid (b) (e.g., terephthalic acid/isophthalic acid mixture at a molar ratio of 5-95/95-5) and an aromatic diol (c) (e.g., hydroquinone) to obtain a liquid crystal polyester of an intrinsic viscosity >=0.5, in which a structural unit (A) of formula II (wherein Ar<1> is phenylene or naphthylene and Ar<3> is phenylene, provided that H of an aromatic ring may be substituted with a halogen, a 1-20C alkyl, aryl, alkoxy or aryloxy), obtained from components (a) and (b), and a structural unit (b) of formula III [wherein formula IV is a residue of (1,4-naphtho)hydroquinone or 2,6-naphthohydroquinone and Ar<4> is Ar<3>], obtained from components (b) and (c), are irregularly arranged in a molar ratio of 95-5:5-95.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an aromatic liquid crystalline polyester.

More specifically, the present invention relates to a novel liquid crystalline polyester with excellent heat resistance and flame retardancy obtained from an aromatic diol containing a phosphorus atom, an aromatic diol, and an aromatic dicarboxylic acid.

(Prior Art) Fully aromatic polyester has been known as a heat-resistant polymer. However, most such polyesters are difficult to process materials and have limited applications. A slight amount of p-oxybenzoic acid homopolymer or copolymer (
Sumitomo Chemical (trade name: Econol), or a polymer consisting of bisphenol A, terephthalic acid, and isophthalic acid (Yunichika (trade name: U-polymer)) were proposed.

Currently, it is just a plain table.

By the way, thermotropic liquid crystal polyesters with excellent processability have been described in many literatures and patents, and are currently being actively researched (for example.

Starting with Japanese Patent Publication No. 58-40976,
Publication No. 3-136098, Publication No. 54-43296,
No. 57-87422, No. 58-62630, No. 58-91812, No. 58-91816, No. 59-85733, etc., and U.S. Patent No. 4
．． No. 161,470, No. 4.219,461, No. 4.
．． No. 256,624, No. 4.279,803, No. 4.
No. 299,756, No. 4.318.841, No. 4.3
No. 18.842, No. 4,330,457, No. 4.3
37.190 specification, etc.).

In general, fully aromatic polyesters have excellent physical properties.
However, since it has a very high melting point and high melt viscosity, it has to be processed at high temperature and pressure, which is extremely inconvenient.

Moreover, prolonged exposure to high temperatures is not a good idea from the perspective of polyester decomposition, and is economically disadvantageous.

Therefore, the development of liquid crystalline polyester with excellent melt processability
There has been a lot of interest and many proposals have been made.

(Problems to be Solved by the Invention) However, in the prior art as described above, it is possible to improve melt processability to some extent.

However, there remained a drawback that the flame retardancy of the polyester itself was insufficient.

The main object of the present invention is to provide a polyester that is particularly suitable for molded articles used at high temperatures.

It has good heat resistance and a high degree of flame retardancy.

The present invention provides a novel liquid crystal polyester.

(Means for Solving the Problems) As a result of extensive research into liquid crystal polyesters with excellent flame retardancy that do not have the above-mentioned problems, the present inventors found that phosphorus-containing polyesters having constitutional units with a specific structure, The present invention was achieved based on the discovery that it has extremely excellent properties.

The present invention has the following configuration. That is, it mainly consists of structural units represented by the following structural formulas (D and (II)).

A liquid crystal polyester having an intrinsic viscosity of 0.5 or more, in which (1,) and (II) are arranged irregularly in a molar ratio of 95:5 to 5:950.

-O-Arl -0-C-Ar3- C-O-Ar2-
0-C-Ar4-C- (in the formula, Ar1) represents a unicine group or a naphthylene group, and -0-A
r2-0- represents a residue of hydroquinone, 1,4-naphthohydroquinone, or 2,6-naphthohydroquinone.

Ar3. Ar4 represents a phenylene group. However, each hydrogen atom in the aromatic ring may be substituted with a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, or an allyloxy group. ) The thermotropic liquid crystal referred to in the present invention refers to the property of polyester molecules regularly arranging in one direction in the molten phase to produce a liquid crystal called a nematic phase. This can be confirmed by technology.

The liquid crystalline polyester of the present invention consists of at least two repeating units, and when these units are combined into a polyester state, the temperature is usually about 400°C or less.

It has been found that thermotropic liquid crystals, which are very easy to process, are formed preferably at temperatures below 350°C (where the melting point of the polyester is measured using differential scanning calorimetry (DSC') when the polyester is sufficiently crystallized). can)
.

The first essential structural unit of the liquid crystal polyester of the present invention is a unit consisting of a phosphorus-containing aromatic diol and an aromatic dicarboxylic acid represented by the structural formula (1).

Specifically, the phosphorus-containing aromatic diol is represented by the following formula (
m), GV), ('iQ, (VDna(')) organic IJ 7 compound.

HOOH Aromatic dicarboxylic acids include, for example, terephthalic acid (
TPA), isophthalic acid (IPA) are preferred;
The molar ratio of A/IPA is 5/95 to 9515°, preferably 20/80 to 90/10. Optimally 50150-70/
It is appropriate to use it as 30.

The second essential structural unit of the liquid crystal polyester of the present invention is a unit consisting of an aromatic diol and an aromatic dicarboxylic acid represented by the above formula (It).

The aromatic diol is hydroquinone (HQ).

, 1.4-naphthoquinone, and 2.6-naphthoquinone. As the aromatic dicarboxylic acid, for example, terephthalic acid (TPA) and isophthalic acid (IPA) are suitable, and the molar ratio of TPA/IPA is 5/95. ~9515° Preferably 20/80~90/10. Optimally 50150~
It is appropriate to use it as 70/30.

On the other hand, the ratio of the structural unit (1) to the structural unit ([) is usually 5/95 to 9515 in molar ratio, preferably 20/8.
0-90/10. The optimum range is 50,150 to 70/30. Outside these ranges, if the amount of the structural unit (1) is too large, the strength will decrease, and if the amount of the structural unit (II) is too large, the melting temperature will be high and the flame retardance will be poor.

Preferred compounds as other copolymerization components include, for example, resorcinol (R8), 4,4'-dicarboxydiphenyl, naphthalic acid, bis(4-carboxyphenyl)methane, 2,2-bis(4-carboxyphenyl)propane. , bis(4-carboxyphenyl)ether, ethylene glycol, cyclohexane dimetatool,
Pentaerythritol, 6-oxy-2-naphthoic acid,
Preferred are p-oxybenzoic acid and the like.

The intrinsic viscosity [η] of the liquid crystal polyester of the present invention is 0.5 or more, preferably 1.0 to io,o, and optimally 1.0.
~5.0. If [η] is less than 0.5, various physical, mechanical and chemical properties including heat resistance will be poor.

It should be noted that if [η] is larger than 10.0, the melt viscosity becomes too high, which may impair moldability, flowability, etc., which is not preferable.

As a preferable example in which the liquid crystal polyester of the present invention can be produced economically, 9,10-dihydro-9-oxa-10-(2',5'-dihydroxyphenyl)phos-7aphenanthrene is used as the first essential structural unit. Constituent unit consisting of 10-oxide (PHQ) and TPA/IPA, hydroquinone (HQ) and TPA/I as the second essential constituent unit
The manufacturing method will be explained using a system using a structural unit consisting of PA.

The acid component consisting of TPA/IPA and the diol component consisting of PHQ/HQ are added in equal number of moles, and further 2 of the diol component is added.
More than double equivalent number (preferably 1.05 to 1.25 times equivalent)
of acetic anhydride (Ac20) was charged into a reactor, and the mixture was heated under normal pressure.

The esterification reaction is carried out at a temperature of about 150° C. for about 2 hours. Thereafter, the temperature is raised initially, and if necessary, under reduced pressure, acetic acid (A
cOH) to carry out an acid exchange reaction.

After that, the final product is 1 t at a temperature of usually 250 to 350°C.
Polycondensation reactions are carried out under highly reduced pressure of less than orr for several hours to several tens of hours, in the molten phase for substances with relatively low melting points (below 350℃), and in the solid phase for substances with relatively high melting points (above 350℃). The liquid crystalline polyester of the present invention can be produced by the following steps.

9Although a catalyst is usually used in the polycondensation reaction.

When producing the liquid crystal polyester of the present invention, one or more compounds selected from, for example, various metal compounds or organic sulfonic acid compounds are used.

Such metal compounds include antimony, titanium, kermanium, tin, zinc, and aluminum.

Compounds such as magnesium, calcium, manganese, L or cobalt are used, while organic sulfonic acid compounds include sulfosalicylic acid, 0-sulfobenzoic anhydride (O3B), and dimethyltin malate. (C8) and O8B are particularly preferably used.

As the catalyst additive, polyester structural unit 1
Normally x10 mol is used per mole.

The details of the temperature conditions and reaction time of the double condensation reaction are as follows:
First, it is usually kept at normal pressure 'F180-300℃ for 4-12 hours.

Preferably, the temperature is 200-290°C for 6-10 hours, most preferably 230-280°C for 8-10 hours.

Furthermore, under reduced pressure (usually 0.01 to 1 torr) 2
1 to 10 hours at 50 to 350°C, preferably 280 to 3
2 to 8 hours at 30℃, *suitably 4 hours at 300 to 330℃
It is preferable to set it as 6 hours. During the polycondensation reaction, depending on the type of polyester structural unit, the temperature may reach a temperature below its melting point and solidify into a solid phase, as described above, or the polyester may be able to undergo polycondensation while remaining in a molten state. be.

(Examples) Hereinafter, the present invention will be explained in more detail by giving examples. The intrinsic viscosity of the polymer in the second row was determined from the solution viscosity measured at 50° C. in a pentafluorophenol solvent.

In addition, the melting point is the differential heat meter () (- Kinnirmar MDS
C-2 type) at a heating rate of 20° C./min, and flame retardancy was determined by flame retardancy according to UL-94IA rating and limit oxygen index according to JIS-7201 standard.

The polyester of the present invention was identified by infrared absorption spectrum, melting point, and elemental analysis, and its liquid crystallinity was confirmed using a Leitz polarizing microscope equipped with a real stage.

Example 1 PHQ, HQ and acetic anhydride in a molar ratio of 10:1 in a reactor
0:22. and TPA in an amount equal to the sum of PHQ and HQ, and added 4 x 10 moles of C3 per mole of polyester structural unit as a catalyst.
The reaction was allowed to proceed at ℃ for 2 hours with mixing. This reaction product was further heated at 250°C under normal pressure for 2 hours.

Further, the reaction was carried out at 260° C. for 2 hours at 50 torr.

After solidifying and pulverizing this reaction product, the reaction was started at 50°C under a reduced pressure of 0.1 torr, and the reaction was carried out by gradually increasing the temperature.
Finally, the temperature was raised to 320°C and solid phase polymerization was carried out for a total of 15 hours. The obtained polyester has an intrinsic viscosity of 0.99
．． Melting point: 399°C, UL-94 standard V-O class.

It was a heat-resistant, flame-retardant crystalline polymer with a limiting oxygen index of 51 and excellent color tone and transparency. Further, when this polyester was analyzed by infrared absorption spectrum, Leitz polarization microscope and elemental analysis, the following results were obtained, and it was confirmed that it was a thermotropic liquid crystal polyester having the following structural units.

That is, in the infrared absorption spectrum, the absorption based on C=O of the aromatic carboxylic acid ester is at 1779, and the absorption based on C=O is at 73.
5 and 782 have para-substituted aromatic absorptions.

An asymmetric trisubstituted aromatic absorption was observed at 888.

On the other hand, the result of single element analysis shows that C=68.8% (theoretical value 6
9.2%), H= 3.42% (theoretical value 3.34
%), P = 5.60% (theoretical value 4.46%).

Example 2 PHQ, HQ, and acetic anhydride were placed in a reactor in a molar ratio of 10:
10:22, and equal molar TPA/IPA (80/20 molar ratio) to the sum of PHQ and HQ.
C8 was added as a catalyst in an amount of 4 x 10 mol per mol of the structural unit of the polyester, and the mixture was reacted with mixing at normal pressure of 150° C. for 2 hours in a nitrogen atmosphere. The reaction mixture was further heated at 250° C. for 2 hours under normal pressure and then at 50 torr.

The reaction was carried out at 260°C for 2 hours. After solidifying and pulverizing this reaction product, the reaction was further started at 150°C under a reduced pressure of 0.1 torr, the temperature was raised sequentially, and the reaction was carried out, and finally the temperature was raised to 320°C, and solid phase polymerization was carried out for a total of 15 hours. . The obtained polyester had an intrinsic viscosity of 0.87. Melting point 374'C.

U'L-94 standard V-O grade, color tone with limit oxygen index 50.

It was a heat-resistant, flame-retardant crystalline polymer with excellent transparency. In addition, this polyester has an infrared absorption spectrum, Le
Analysis using an itz polarization microscope and elemental analysis gave the following results, confirming that it was a thermotropic liquid crystal polyester having a repeating unit of the following structure.

0 I+ That is, in the infrared absorption spectrum, the absorption based on C=0 of the aromatic carboxylic acid ester is at 1777, and the absorption based on C=0 is at 73
Absorption of para-substituted aromatics at 4 and 780.

Asymmetrical 3t to 885! t, absorption of exchanged aromatics was observed.

On the other hand, the results of nine element analysis show that C=68.9% (theoretical value 6
9.2%), H = 3.37% (theoretical value 3.34%
), P = 5.70% (q theory value 4.46%) was obtained.

Example 3 PHQ and I (Q, R3 and acetic anhydride in molar ratio lo: 8:2:22) and PI (TPA/I PA (90/10 molar ratio), added 4 x 10 mol of C8 as a catalyst per 1 mol of polyester structural unit, and heated at 150 molar pressure under nitrogen atmosphere.
The reaction was allowed to proceed at ℃ for 2 hours with mixing. This reaction product was further reacted at 250° C. for 2 hours under normal pressure, and further at 260° C. for 2 hours at 50 torr. After solidifying and pulverizing this reaction product, the reaction was further started at a reduced pressure of 0.1 torr'F150C, and the reaction was carried out by successively increasing the temperature.
The temperature was raised to .degree. C. and solid phase polymerization was carried out for a total of 15 hours. The obtained polyester has an intrinsic viscosity of 1.23° and a melting point of 346°C.
, UL-94 standard V-O class, color tone with limit oxygen index 53,
It was a heat-resistant, flame-retardant crystalline polymer with excellent transparency. In addition, this polyester has an infrared absorption spectrum, Le
When analyzed using an itz polarizing microscope and an elemental analyzer, the following results were obtained: 1. It was confirmed that it was a thermotropic liquid crystal polyester having a repeating unit with the following structure.

That is, in the infrared absorption spectrum, the absorption based on C=O of the aromatic carbo/acid ester is at 1779, and the absorption based on C=O is at 73.
5 and 781 have para-substituted aromatic absorptions.

An asymmetric trisubstituted aromatic absorption was observed at 887.

On the other hand, in the results for one element, C = 68.7% (
Theoretical value 69.2%), H = 3.36% (Theoretical value 3.34
%), P=5.42% (theoretical value 4.461).

The results of Examples 1 to 3 are listed in Table 1.

Examples 4 to 13 PHQ, HQ, R8, TPA in the molar ratios shown in Table 1,
A liquid crystal polyester was produced in the same manner as in Example 1 using IPA. The obtained liquid crystalline polyester was identified by infrared absorption spectrum, Leitzfl-element microscopy, melting point and elemental analysis.

The results of Examples 4 to 13 are listed in Table 1.

Table 1 Examples 14 to 16 A liquid crystal polyester was obtained in the same manner as in Example 2, except that another phosphorus compound was used instead of PHQ. The obtained liquid crystalline polyester was identified by infrared absorption spectrum-Leitz polarized light microscopy@2 melting point and elemental analysis.

The results of Examples 14 to 16 are listed in Table 2.

In Table 2, ■, (V), and (Vl) are phosphorus compounds having horizontal formulas θ■, (V), and (VD, respectively) described in the text.

Comparative Examples 1 and 2 In Example 1, the charging molar ratio of PHQ and HQ was 99.
An experiment was carried out in the same manner as in Example 1 except that = 1 or 1:99.
In the case of 9:l, it became a crystalline polyester with a melting point of 405° C., and did not become a thermotropic liquid crystal even when heated above the melting point. Similarly, when the molar ratio was 99, the melting point was extremely high, and decomposition began at 450° C., and virtually no melting point was observed, making it difficult to melt and mold, making it impossible to put it to practical use.

(Effect of the invention) The liquid crystal polyester of the present invention is.

(1) Since it has a specific phosphorus-containing structural unit in its side chain, it not only does not decompose even when used at high temperatures, but also has a high degree of flame retardancy when molded.

(2) The main chain is mainly composed of HQ and TPA/IPA units, which facilitates the formation of mototropic liquid crystals.

At the same time, it falls within the preferred melting point range (300-400°C).

Excellent heat resistance and moldability.

It is a new liquid crystal polyester that has excellent physical properties as a heat-resistant polymer. As described above, the liquid crystalline polyester of the present invention is useful as a material for films, fibers, and molding materials used in applications requiring a high degree of heat resistance and flame retardancy.

Claims (1)

[Claims] (1) Mainly composed of structural units represented by the following structural formulas (I) and (II), where (I) and (II) are 95:5
Intrinsic viscosity 0.5 irregularly arranged in a molar ratio of ~5:95
More than liquid crystal polyester. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, Ar_1 represents a phenylene group or a naphthylene group, and -O-Ar_2-O- Hydroquinone, 1,4-naphthohydroquinone or 2,6
- Indicates the residue of naphthohydroquinone, Ar_3, Ar
_4 represents a phenylene group. However, each hydrogen atom in the aromatic ring may be substituted with a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, or an allyloxy group. )