JPH0516452B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a novel copolyester with excellent heat resistance and flame retardancy obtained from an aromatic shiol containing a phosphorus atom, an alkylene glycol, an aromatic dicarboxylic acid, and an aromatic oxycarboxylic acid. It is related to. (Prior Art) Aromatic polyesters have been known as heat-resistant polymers. However, most such polyesters are difficult to process materials and have limited applications. Only a few 4-hydroxybenzoic acid homopolymers and 4-hydroxybenzoic acid polymers (Sumitomo Chemical, trade name Econol), or polymers consisting of bisphenol A, terephthalic acid, and isophthalic acid (Unirica, trade name U-polymer) have been proposed and are currently on the market. It's just that. By the way, liquid crystal polyesters with excellent processability and melt anisotropy have been described in many literatures and patents, and are currently being actively researched (for example, Publication No. 53-136098, Publication No. 54-43296, Publication No. 57
-87422 publication, 58-62630 publication, 58-
Publication No. 91812, Publication No. 58-91816, Publication No. 59-85733
Publications, etc., as well as U.S. Patent Nos. 4161470 and 4161470.
4219461, 4256624, 4279803, 4219461, 4256624, 4279803,
No. 4299756, No. 4318841, No. 43218842, No.
No. 4330457, specification No. 4337190, etc.). In general, heat-resistant aromatic polyesters are said to have excellent flame retardancy, but the limiting oxygen index (described below) is at most 40, which is difficult to say that they have sufficient flame retardancy, and they also have very low melting points. It is extremely inconvenient because it has a high melt viscosity and must be processed at high temperature and pressure. On top of that,
Prolonged exposure to high temperatures is not a good idea from the standpoint of polyester decomposition, and is also economically disadvantageous. Therefore, interest has been focused on the development of liquid crystalline polyester with excellent flame retardancy and melt processability, and many proposals have been made. (Problems to be Solved by the Invention) However, in the prior art as described above, in addition to insufficient flame retardance, high temperatures of 300°C or higher are also required for melt molding. It has been considered extremely difficult to achieve both melt processability and flame retardancy of polyester. Therefore, the main object of the present invention is to provide a polyester that is particularly suitable for molded articles used at high temperatures, and to provide a novel copolyester that has good melt processability and high flame retardancy. It's about doing. (Means for Solving the Problems) As a result of extensive research into polyesters with excellent flame retardancy that do not have the above-mentioned problems, the present inventors have found that phosphorus-containing copolyesters with a specific structure have extremely excellent properties. discovered that it has certain properties,
We have arrived at the present invention. That is, the present invention provides the following structural formulas (), ()
It mainly consists of the structural units shown by and (), and the molar ratio of () and () is 90:10 to 10:90.
and the molar ratio of the sum of () and () to () is 95:5 to 5:95, (),
Intrinsic viscosity 0.5 with () and () arranged irregularly
The gist is the above copolyester. (In the formula, Ar ¹ is a trivalent aromatic group, and Ar ² is a divalent aromatic group. However, the aromatic ring or alkylene chain may be substituted with a substituent. Also, n ¹ is 2 ~4, ⁿ² represents an integer of 1 to 2.) The copolyester of the present invention has crystallinity, amorphous or thermotropic liquid crystallinity, but in order to achieve both heat resistance and moldability, thermotropic Particularly preferred is a tropic liquid crystal. The thermotropic liquid crystal property referred to in the present invention refers to the property in which polyester molecules are regularly arranged in one direction in the melt phase to produce a liquid crystal called a nematic phase. This can be confirmed using polarization technology. The copolyester of the present invention consists of at least three structural units, and these structural units, when combined into a polyester state, have a melting point (softening point in the case of thermotropic liquid crystalline or amorphous polyester). is usually below about 300℃,
It has been found that a thermotropic liquid crystalline melt phase which is very easy to process is formed preferably at temperatures below 300°C. The first structural unit constituting the copolyester of the present invention is a unit consisting of a phosphorus-containing aromatic diol and an aromatic dicarboxylic acid represented by the above structural formula (). Ar ¹ in structural formula () is preferably a benzene ring or a naphthalene ring. Also,
The hydrogen atom of the aromatic ring in structural formula () may be substituted with an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group, an allyloxy group, or a halogen atom. Specific examples of the phosphorus-containing aromatic diol include organic phosphorus compounds having structural formulas (), (), (), (), and the like. As the aromatic dicarboxylic acid, for example, terephthalic acid (TPA) and isophthalic acid (IPA) are suitable, and the molar ratio of TPA:IPA is 100:0 to 0:100,
Preferably 100:0 to 50:50, optimally 100:0 to
It is appropriate to use it as 70:30. The second structural unit constituting the copolyester of the present invention is a unit represented by the above structural formula (), and is an alkylene terephthalate unit consisting of TPA and alkylene glycol. Structural formula()
The alkylene chain in may be substituted with an alkylene group having 1 to 20 carbon atoms or a halogen atom. As the alkylene glycol, it is preferable to use glycols such as ethylene glycol, trimethylene glycol, neopentyl glycol, tetramethylene glycol, and propylene glycol. The third structural unit constituting the copolyester of the present invention is a unit represented by the above structural formula (),
Examples include 4-hydroxybenzoic acid residue and 6-oxy-2-naphthoic acid residue. The hydrogen atom of the aromatic ring in structural formula () has 1 carbon atom
~20 alkyl groups, aryl groups, alkoxy groups,
It may be substituted with an allyloxy group or a halogen atom. The ratio of structural units () to structural units () is usually 90:10 to 10:90 in molar ratio, preferably 80:
20-20:80, optimally 60:40-40:60. Outside these ranges, if the number of structural units () increases too much, the strength will decrease, and if the number of structural units () increases, the heat resistance will deteriorate. On the other hand, the ratio of the sum of structural units () and () to the structural unit () is usually 95:5 to 5:95 in molar ratio.
and preferably 80:20 to 10:90, optimally
50:50 to 10:90. Outside of these ranges,
If the number of structural units () and () is too large, the strength and heat resistance will decrease, and if the number of structural units () is too large, the melting temperature will become high and the flame retardance will become inferior. In addition, components other than those mentioned above may be copolymerized within a range that does not impair the purpose of the present invention. Examples of such copolymerization components include resorcinol (RS), hydroquinone (HQ), and 4,4-dihydroxy Diphenyl, naphthalic acid, 2,2-bis(4'-carboxyphenyl)propane, bis(4-carboxyphenyl)methane, bis(4-carboxyphenyl)ether, ethylene glycol, cyclohexanedimethanol, pentaerythritol etc. are suitable. The intrinsic viscosity [η] of the copolyester of the present invention is usually 0.5 or more, preferably 1.0 to 10.0, optimally 1.0 to 10.0.
5.0 is appropriate. When [η] is less than 0.5, various physical, mechanical,
Poor chemical properties. Note that if [η] is larger than 10.0, the melt viscosity becomes too high, which may impair moldability, fluidity, etc., which is not preferable. As a preferable example in which the copolyester of the present invention can be produced economically, the first structural unit is 9,10-
A structural unit consisting of dihydro-9-oxa-10-(2',5'-dihydroxyphenyl)phosphaphenanthrene-10-oxide (PHQ) and TPA/IPA, the second structural unit is TPA and ethylene glycol ( A method for producing a copolyester having an ethylene terephthalate unit consisting of EG) and a third constitutional unit consisting of a 4-hydroxybenzoic acid (4HBA) residue will now be described. The acid component consisting of TPA/IPA, the diol component consisting of PHQ, and the oxycarboxylic acid component consisting of 4HBA are added in such amounts that the hydroxyl groups and the carboxyl groups are equivalent, and the amounts of these and the hydroxyl groups are equivalent or more (preferably 1.05 to 1.25 times equivalent) of acetic anhydride (Ac ² O) is charged into the reactor, or an acid component consisting of TPA/IPA and a diol component consisting of PHQ diacetate (PHQ-A) are combined.
An oxycarboxylic acid component consisting of 4HBA acetate (4HBA-A) is reacted with Ac ² O in an amount such that the hydroxyl group and the carboxy group are equivalent, preferably 0.05 to 0.25 times equivalent to the amount of hydroxyl residue. The mixture is charged into a machine and subjected to an acid exchange reaction or an esterification reaction at a temperature of about 150°C under normal pressure for about 2 hours. After that, the temperature is raised sequentially, and acetic acid (AcOH) is distilled out under reduced pressure if necessary, and after an acid exchange reaction, the temperature is raised to about 280℃. Meanwhile, polyethylene terephthalate (PET)
Alternatively, a polyalkylene terephthalate such as polybutyterephthalate (PBT) is prepared separately, and this and the reactant are melt-mixed at a temperature of about 280°C. Then, finally at a temperature of usually 280-350℃,
The copolyester of the present invention can be produced by carrying out a polycondensation reaction in the melt phase or solid phase under a high vacuum of less than 1 torr for several tens of minutes to several hours. The PET is prepared by polycondensing bis-(β-hydroxythiel) terephthalate and/or its low polymer (BHET) obtained from TPA and EG by any known method. As mentioned above, depending on the type of polyester, depending on the type of polyester structural unit during the polycondensation reaction, it may solidify and become a solid state, or it may remain in a molten state. In some cases, polycondensation can occur. In addition, catalysts are usually used in polycondensation reactions,
To produce the copolyester of the present invention, one or more compounds selected from, for example, various metal compounds or organic sulfonic acid compounds are used. As such metal compounds, compounds such as antimony, titanium, germanium, tin, zinc, aluminum, magnesium, calcium, manganese or cobalt, and sodium are used, while as organic sulfonic acid compounds, sulfosalicylic acid, o-sulfo anhydride, etc. are used. Benzoic acid (OSB)
Among these compounds, dimethyltin malate (CS) and OSB are particularly preferably used. The amount of the catalyst added is usually 0.1 x 10 ^-4 to 100 x 10 ^-4 mol per 1 mol of the polyester structural unit.
It is preferably used in an amount of 0.5×10 ^-4 to 50×10 ⁻⁴ mol, most preferably 1×10 ⁻⁴ to 10×10 ⁻⁴ mol. (Example) Hereinafter, the present invention will be explained in more detail by giving examples. In addition, the intrinsic viscosity of the polymer in the example was determined from the solution viscosity measured at 20° C. in a mixed solvent of equal weights of phenol and tetrachloroethane. In addition, the melting point and glass transition point were measured using a differential scanning calorimeter (Model DSC-2 manufactured by PerkinElmer) at a heating rate of 20°C/min. According to the limiting oxygen index according to the 7201 standard,
I judged it. On the other hand, the liquid crystal polyester according to the present invention was fixed by infrared absorption spectrum, melting point and elemental analysis, and liquid crystallinity was confirmed using a Leitz polarizing microscope equipped with a hot stage. Reference example 1 TPA is added to the esterification reactor where BHET is present.
and EG slurry (TPA-EG molar ratio 1:1.6)
is continuously supplied at a temperature of 260℃, 0.05Kg/cm ² G
BHET was obtained continuously under a pressure of 6 hours with a residence time of 6 hours. This BHET was charged into a batch-type polymerization reactor, and 2.5×10 ^-4 mol of CS was added as a catalyst per 1 mol of the polyester structural unit, and the reaction rate was 1 torr.
The reaction was carried out at 280℃ for 2 hours under reduced pressure of
0.67, a melting point of 255°C, and a glass transition point of 71°C. Reference example 2 TPA dimethyl ester and 1,4-butanediol were placed in a transesterification reactor and heated to 220°C.
After carrying out the transesterification reaction at a temperature of ^-4 mol was added and reacted for 3 hours at 240℃ under a reduced pressure of 1torr, resulting in an intrinsic viscosity of 1.10 and a melting point of 228℃.
Manufactured PET. Example 1 PHE-A, TPA, 4HBA and Ac ² O in the reactor
Prepared in a molar ratio of 20:20:70:10,
Add 4 x 10 -4 mol of CS to 1 mol of polyester structural unit as a catalyst, and add 4 x 10 ^-4 mol of CS to 1 mol of polyester structural unit, under nitrogen atmosphere at normal pressure 150
The reaction was allowed to proceed at ℃ for 2 hours with mixing. This reaction product was further heated at 200°C for 2 hours under normal pressure, and then at 280°C for 2 hours.
Allowed time to react. This reaction product and the product obtained in Reference Example 1
PET and repeating unit molar ratio of 90:10
The mixture was mixed for 20 minutes at a temperature of 280°C under nitrogen, and then the temperature was raised sequentially, and finally the temperature was raised to 310°C, and polymerization was carried out for a total of 12 hours. The obtained copolyester had an intrinsic viscosity of 1.85, a melting point of 298°C, a UL94 design V-O class, a limiting oxygen index of 61, and excellent color tone and transparency.
Furthermore, when this copolyester was analyzed by infrared absorption spectroscopy, Leitz polarization microscope, and elemental analysis, the following results were obtained. :70 molar ratio. That is, in the infrared absorption spectrum,
1778κ is the absorption based on C=O of aromatic carboxylic acid ester, 734κ and 784κ are the absorptions of para-substituted aromatics, 886κ is the absorption of non-contrast trisubstituted aromatics, 2875κ,
An absorption based on methylene group was observed at 2950κ. On the other hand, the results of elemental analysis show that C = 67.9% (theoretical value
68.7%), H = 3.3% (theoretical value 3.4%), P = 3.3%
(Theoretical value: 3.2%). Example 2 PHQ, TPA, 4HBA and Ac ² O were charged into a reaction apparatus at a molar ratio of 10:10:60:100,
Add 4 x 10 -4 mol of CS to 1 mol of polyester structural unit as a catalyst, and add 4 x 10 ^-4 mol of CS to 1 mol of polyester structural unit, under nitrogen atmosphere at normal pressure 150
The reaction was allowed to proceed at ℃ for 2 hours with mixing. This reaction product was further heated at 200°C for 2 hours under normal pressure, and then at 280°C for 2 hours.
Allowed time to react. Obtained from this reaction product and Reference Example 2
PBT and repeating unit molar ratio of 70:30
Mix for 20 min under nitrogen at a temperature of 280 °C,
Thereafter, the temperature was raised sequentially, and finally the temperature was raised to 310°C, and polymerization was carried out for a total of 12 hours. The obtained copolyester had an intrinsic viscosity of 2.03, a melting point of 294°C, a UL94 standard V-0 class, a limiting oxygen index of 58, and was excellent in color tone and transparency.
In addition, when this copolyester was analyzed by infrared absorption spectroscopy, Leitz polarization microscope, and elemental analysis, the following results were obtained. It was confirmed that the copolyester had a molar ratio of :60 and did not have thermotropic liquid crystallinity. That is, in the infrared absorption spectrum,
Absorption based on C=O of aromatic carboxylic acid ester at 1780κ, absorption of para-substituted aromatics at 733κ and 779κ, absorption of asymmetric trisubstituted aromatics at 891κ, 2870κ,
An absorption based on methylene group was observed at 2935κ. On the other hand, the results of elemental analysis show that C = 69.7% (theoretical value
68.0%), H = 3.9% (theoretical value 4.1%), P = 1.8%
(Theoretical value: 1.7%). Examples 3 to 7 PHQ, 4HBA, PET in the molar ratio shown in Table 1,
A copolyester was produced in the same manner as in Example 1 using RS, TPA, and IPA. The resulting copolyester was identified by infrared absorption spectroscopy, Leitz polarization microscopy, melting point and elemental analysis. The results of Examples 3 to 7 are listed in Table 1. Examples 8-10 Copolyesters were produced in the same manner as in Example 1, except that other phosphorus compounds were used in place of PHQ. The resulting copolyester was identified by infrared absorption spectroscopy, Leitz polarization microscopy, melting point and elemental analysis. The results of Examples 8 to 10 are listed in Table 1. In addition, (), (), and () in Table 1 represent the structural formulas (), (), and () described in the main text, respectively.
It is an organic phosphorus compound having ().

[Table] In Table 1, PAT represents polyalkylene terephthalate. (Effects of the Invention) The copolyester of the present invention has (1) a specific phosphorus-containing structural unit in its side chain, so it not only does not decompose even when used at high temperatures, but also has a high resistance to decomposition when made into a molded product. (2) Since the main chain is mainly composed of PHQ, TPA and 4HBA residues, it is easy to form a thermotropic liquid crystal phase, and at the same time it has a high melting point (280℃). (~300℃) and has excellent heat resistance. (3) As there is an alkylene chain in a part of the main chain, it has a moderate degree of flexibility and excellent moldability. This is a new copolyester that has excellent properties as a heat-resistant polymer. As described above, the copolyester of the present invention is useful as a material for films, fibers, and molding materials used in applications requiring heat resistance and high flame retardancy.

Claims (1)

[Scope of Claims] 1 Mainly composed of structural units represented by the following structural formulas (), () and (), the molar ratio of () and () is 90:10 to 10:90, and () and The molar ratio of the sum of () and () is 95:5 to 5:
A copolyester with an intrinsic viscosity of 0.5 or more in which (), () and () are arranged irregularly at a molar ratio of 95. (In the formula, Ar ¹ is a trivalent aromatic group, and Ar ² is a divalent aromatic group. However, the aromatic ring or alkylene chain may be substituted with a substituent. Also, n ¹ is 2 ~4, ⁿ² represents an integer of 1 to 2.) 2. The copolyester according to claim 1, wherein the copolyester is a thermotropic liquid crystalline polyester. 3. The copolyester according to claim 1 or 2, wherein the structural units represented by structural formulas () to () are structural units represented by the following formulas () to (), respectively.