JPH04264127A - Production of aromatic polyester - Google Patents

Abstract

PURPOSE:To produce an arom. polyester which has an excellent moldability, a high hydrolysis resistance due to its low carboxyl group content, and a high resistance to coloration. CONSTITUTION:In producing an arom. polyester by reacting isophthalic acid, hydroquinone, and an optionally substd. phenol in the presence of a catalyst. at least 50% of isophthalic acid is esterified, mixed with a polymer and/or an oligomer of an aryl carbonate, and thermally melted and reacted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrially advantageous method for producing an optically isotropic aromatic polyester having excellent heat resistance, mechanical properties and chemical resistance.

0002

BACKGROUND OF THE INVENTION Aromatic polyesters containing isophthalic acid as the main acid component and hydroquinone as the main diol component have been well known. Among them, regarding aromatic polyesters containing bisphenol-A as a copolymerization component, for example, Japanese Patent Publication No. 63-49610 and Japanese Patent Publication No. 63-49610 and Japanese Patent Publication No. 63-49610
3-49611 describes a polyester consisting of diphenyl isophthalate, hydroquinone, and bisphenol-A.

[0003] However, diphenyl isophthalate is relatively expensive, and the above-mentioned polyester using it as a main raw material has the problem of high cost. In addition, the above-mentioned Special Publication No. 63-49610 and Special Publication No. 63-4961
No. 1 describes an example in which a polymer is obtained by esterifying isophthalic acid, aromatic diol, and phenol by heating, and then reacting and polymerizing with bisphenol-A. Polymers are easily colored, and because they have many terminal carboxyl groups, they are easily hydrolyzed.

0004

[Object of the Invention] Therefore, the present inventors have developed a method that has excellent moldability.
The present invention was achieved as a result of extensive research aimed at obtaining an aromatic polyester that has fewer terminal carboxyl groups, good hydrolysis resistance, and less coloring.

[0005]

[Structure of the Invention] The present invention provides a method for reacting isophthalic acid (A), hydroquinone (B), and phenol (C) which may have a substituent in the presence of a catalyst. 50% or more of (A) is esterified, and then the following formula (I)

[0006]

This is a method for producing an aromatic polyester, which is characterized by adding a polymer and/or oligomer of aryl carbonate (D) having a repeating unit represented by the following formula to make it heat-melt reactive.

That is, the present invention makes it possible to achieve the above object by adding the aryl carbonate (D) component in the form of a polymer and/or oligomer.

In the present invention, isophthalic acid is used as component A, which is one of the raw materials, but a small proportion thereof, for example, 10 mol % or less, may be replaced with another type of aromatic dicarboxylic acid. Examples of such aromatic dicarboxylic acids include terephthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, and diphenylsulfone dicarboxylic acid.

[0009] Examples of the phenol which may have a substituent used as the C component include phenol, m-cresol, p-cresol, m-chlorophenol, p-butylphenol, p-amylphenol, p-chlorophenol, etc. Among these, phenol and cresol are preferred, and phenol is particularly preferred.

[0010] This component C does not become a constituent component of the polyester to be produced, but acts as a reaction medium for the initial reaction described below.

As component D, an aryl carbonate polymer and/or oligomer having a repeating unit represented by the above formula (I) is used. The degree of polymerization of such aryl carbonate is not particularly limited.

In the present invention, the above (A), (B), (
C) and (D) components are represented by the following formula (II)
0.9≦(B+D)/A≦1.3
...(II) [Here, A is the number of moles of component A,
B is the number of moles of component B, and D is the number of moles of the repeating unit represented by the above formula (I). ] Following formula (III) 0.07≦D/(A+B+D)≦
0.3...(III) [Here, A, B,
D is the same as defined in formula (II). ] and the following formula (I
V) 0.05≦C/A
...(IV) [
Here, A is the same as defined in formula (II), and C is the number of moles of the C component. ] It is preferable to react under conditions that simultaneously satisfy the following.

Here, in formula (II), (B+D)
If the /A ratio is less than 0.9, the degree of polymerization of the polymer will be difficult to increase and coloring may occur during the reaction, which is undesirable.If it exceeds 1.3, no further effects can be expected.

Further, the formula (II) is preferably in the range of 0.95 to 1.2.

In formula (III), D/(A+B
If the ratio of +D) is less than 0.07, the melting point of the resulting polymer will become too high, making melt polymerization and molding difficult, which is not preferable. Further, if this ratio exceeds 0.3, the originally expected excellent heat resistance, chemical resistance, and mechanical properties are impaired, which is not preferable.

[0016] Furthermore, the formula (III) is 0.1 to 0.2
It is preferably in the range of 5.

In formula (IV), the ratio of C/A is
If it is less than 0.05, the reaction is slow and the reactants are likely to decompose and become colored, which is not preferable. The amount used is preferably 0.1 to 5 times the mole, more preferably 0.2 to 2 times the mole, particularly preferably 0.3 to 1.5 times the mole.

[0018] In the method of the present invention, a catalyst is used in addition to the above-mentioned components, and as the catalyst, compounds commonly used as esterification and transesterification catalysts are preferably used.

Examples of preferred catalysts include antimony trioxide, stannous acetate, dibutyltin oxide, germanium oxide, and titanium tetrabutoxide.

[0020] The method of the present invention is a method for obtaining polyester by esterification and transesterification reactions, but it can be broadly divided into two reactions: an initial reaction and a polymerization reaction. The reaction is carried out in two steps: a preliminary step in which the group is esterified with two components, component B and component C, and a subsequent step in which component D is added and reacted.

[0021] In the stage before the initial reaction, at least 50% of the carboxyl groups are reacted with the hydroxy components (B, C) and esterified. At this stage, water is produced by the reaction, so water is added to the reaction system. leave outside. At this stage, it is necessary to prevent component C from being distilled out of the reaction system.

In the later stage of the initial reaction, the newly added component D reacts with the carboxylic acid component and the hydroxyl component to advance the esterification reaction, and the reaction in the earlier stage further advances.

[0023] In the next polymerization reaction, the esterification is further progressed and at the same time the ester of the carboxylic acid component and the C component formed so far is combined with other hydroxy components, that is, the B component and/or the ester.
Alternatively, this is the stage where the exchange reaction with component D also progresses and polymerization progresses, and at this stage, component C is also distilled out of the reaction system along with water. Although the initial reaction and the polymerization reaction cannot be clearly separated, they are distinguished in that in the initial reaction, the C component is actively prevented from being distilled out of the reaction system, and in the polymerization reaction, it is distilled off.

The reaction temperature of the initial reaction varies depending on the catalyst, but is 150°C or higher, preferably 180°C or higher, particularly preferably 230°C or higher, and is preferably raised as the reaction progresses. The upper limit in this case is 330°C, preferably about 300°C.

The initial reaction can be carried out under normal pressure to elevated pressure, but if the boiling point of component C at normal pressure is particularly lower than the reaction temperature, it is preferable to carry out the reaction under elevated pressure. Further, the reaction system is preferably under an inert gas atmosphere such as nitrogen or argon.

[0026] The reaction time may be any time that is sufficient for the above-mentioned esterification reaction to proceed sufficiently, and this time may vary depending on the reaction time, reaction scale, etc., but may range from 30 minutes to 20 minutes.
time, preferably about 1 to 10 hours.

[0027] During the above reaction, it is preferable to remove water generated by esterification from the reaction system. The esterification reaction is an equilibrium reaction, and as the produced water is removed from the system, the reaction progresses and the yield and purity of the product improve. The generated water can be removed from the reaction system due to the boiling point difference with component C, but it can also be removed from the reaction system by azeotropy using an organic solvent that forms an azeotrope with water. . Any organic solvent may be used as long as it does not decompose itself under the reaction conditions, is substantially stable in the reaction system, and is azeotropic with water. Specifically, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene can be preferably used.

The reaction rate of the esterification reaction in the initial reaction is preferably 50% or more. This esterification reaction rate can be determined by the amount of water produced by the reaction, but in order to determine it more accurately, it can also be determined by taking out a portion of the reaction product and measuring the unreacted -COOH value. can.

The esterification rate in the initial reaction is more preferably 60% or more, particularly preferably 70% or more. The reaction temperature in the polymerization reaction is from the initial reaction temperature to 380°C.
Preferably carried out at <0>C. In the method of the present invention, it is necessary to carry out the polymerization reaction while the polyester is melted. As the melting point of the reactant increases as the polymerization progresses, it is preferable to carry out the reaction while gradually increasing the temperature. For example, if the intrinsic viscosity of the polymer is up to about 0.5, it is preferably carried out at a temperature of 330°C or lower. If the temperature is higher than that, melt polymerization is preferably carried out at a temperature of 330°C or higher and 360°C or lower.

Since the aromatic polyester obtained by the method of the present invention has a relatively high melt viscosity, when increasing the degree of polymerization by melt polymerization, it is preferable to carry out the polymerization in a Ruder type reactor or the like.

[0031] The polymerization reaction is carried out under reduced pressure or by flowing an inert gas, and the water produced as a result of the reaction, the C component, and if necessary, the dihydroxy aromatic compound such as the B component used in excess are forcibly removed from the reaction system. I will do it while doing it.

The intrinsic viscosity of the polyester obtained by the method of the present invention is preferably from 0.4 to 2.0, more preferably from 0.6 to 1.5.

[0033] In the method of the present invention, a stabilizer can be used as appropriate, and the stabilizer is preferably a conventionally known trivalent or pentavalent stabilizer.
Examples of phosphorus compounds or esters thereof that can be used include phosphorous acid, phosphoric acid, phenylphosphonic acid, triphenylphosphite, triphenylphosphate, and triphenylphosphine.

[0034]

According to the method of the present invention as described above, an optically isotropic, linear aromatic polyester with a high degree of polymerization can be produced using inexpensive raw materials and only by melt polymerization. Further, according to the method of the present invention, a polyester having excellent moldability, a small number of terminal carboxyl groups, and good hydrolysis resistance can be obtained. Moreover, such polyester has little coloring. The polyester can be subjected to conventional melt molding such as extrusion molding and injection molding. Moreover, the molded products obtained by melt-molding the polyester have good mechanical properties, dimensional stability,
This polyester not only has excellent heat resistance and chemical resistance, but also has low water absorption, making it extremely useful as a material for engineering plastic fibers, films, and the like.

[0035]

[Examples] The present invention will be explained in detail with reference to Examples below. In the examples, "parts" simply means "parts by weight", and the intrinsic viscosity of the polymer is a value measured at 35°C using a mixed solvent of P-chlorophenol/tetrachloroethane (weight ratio 40/60). . Further, the melting point (Tm) and glass transition temperature (Tg) of the polymer were measured using DSC at a heating rate of 10° C./min. In addition, the terminal carboxyl group (CV
), the polymer dissolved in the above mixed solvent was mixed with NaOH/
It was determined by back titration using a benzyl alcohol solution.

Note that this example does not limit the content of the present invention in any way.

[0037]

[Example 1] 191 parts of isophthalic acid, 1 part of hydroquinone
07.5 parts of phenol, 108 parts of phenol, and 0.10 parts of antimony trioxide were charged into a reactor equipped with a stirring device and a distillation system, and the reactor was pressurized with nitrogen and heated to 280°C. pressure 5kg
The pressure was gradually lowered from 2 kg/cm2 to 2 kg/cm2, water produced by the reaction was distilled out of the system, and the reaction was continued for 5 hours. During this time, 29.8 parts of water was produced (esterification reaction rate: 72%). Next, the reaction system was returned to normal pressure, 102 parts of poly(4,4'-isopropylidene diphenylene carbonate) having a molecular weight of approximately 20,000 was added, and the reaction was allowed to proceed for 60 minutes under a nitrogen stream while distilling volatile components out of the system. . Here, A
/B/C/D ratio corresponds to 100/85/100/35, formula (II) = 1.2, formula (III) = 0.16,
Formula (IV)=1. During this time, the reaction temperature was raised from 280°C to 340°C. Next, the pressure inside the system was gradually reduced, and after 60 minutes, approximately 0.5 m
The reaction was carried out under high vacuum of mHg for 60 minutes to obtain a polymer.

The obtained polymer had an intrinsic viscosity of 0.70, a melting point of 308°C, and a Tg of 153°C. This polymer exhibited isotropy in the molten state, and was a polymer with good color tone and little coloration. The CV of this polymer is 16 (equivalent/10
6 g).

[0039]

[Example 2] The molar ratio of A/B/C/D is 100/70/
100/35 and the molecular weight of polycarbonate is approximately 100
All polymers were polymerized by the method shown in Example 1 except that the polymer was set to 0. Here, in Example 2, formula (II)=1.
05, formula (III)=0.17, and formula (IV)=1. The obtained polymer had an intrinsic viscosity of 0.69 and a CV=1
．． 3 (equivalent amount/106 g).

[0040] This polymer exhibited an isotropic melt state and had a good color tone.

After pulverizing this polymer and heating it in water at 150°C in an autoclave for 10 hours, the intrinsic viscosity was 0.
．． It was 67.

[0042]

[Comparative example] By the method shown in Example 1, isophthalic acid 19
1 part of hydroquinone, 80.5 parts of hydroquinone, and 108 parts of phenol were reacted to perform an esterification reaction. The esterification reaction rate calculated from the distilled water was 60%.

Next, the reaction system was returned to normal pressure, 91.7 parts of bisphenol-A was added, and the reaction was allowed to proceed for 60 minutes under a nitrogen stream while distilling volatile components out of the system. Here A/B/
C/D=100/70/100/35, and the formula (II
)=1.05, formula (III)=0.13, formula (IV)
=1. Furthermore, the reaction was carried out in the same manner as shown in Example 1 to obtain a polymer.

The intrinsic viscosity of the polymer is 0.71, CV=7
8 (equivalent amount/106 g).

The hydrolysis resistance of this polymer was examined in the same manner as shown in Example 2, and the intrinsic viscosity after heat treatment was found to be 0.33.

[0046]

Examples 3 to 5 Polymers were polymerized in the same manner as in Example 1. The results are shown in the table below.

[0047]

[Table 1]

Claims (1)

[Claims] [Claim 1] Isophthalic acid (A), hydroquinone (B), and phenol (C) which may have a substituent
In a method of reacting each component in the presence of a catalyst,
Esterify at least 50% of the above isophthalic acid (A), then add a polymer and/or oligomer of aryl carbonate (D) having a repeating unit represented by the following formula (I) and melt by heating. A method for producing aromatic polyester characterized by making it reactive.