JPH06306152A - Production of aromatic polyester - Google Patents

Abstract

PURPOSE:To obtain an arom. polyester which, when it is melt molded, gives an article excellent in heat resistance, mechanical properties, and solvent resistance by producing the polyester under specified conditions. CONSTITUTION:Isophthalic acid or an arom. carboxylic acid component mainly comprising the acid is thermally reacted in melt with hydroquinone and a (substd.) phenol compd. under specified conditions to give a product with a specified degree of esterification and unreacted COOH groups of the product are thermally reacted in melt with a diaryl carbonate and a dihydroxy compd. of formula VI under specified conditions in the process for producing an amorphous arom. polyester which substantially comprises structural units of formulas I, II, and III [wherein A<1> and A<2> are each (substd.) phenylene; and X is a group of formula IV (wherein R<1> and R<2> are each H, halogen, 1-6C alkyl, 5-6C cycloalkyl, 6-12C aryl, or aralkyl) or a 1,1-cycloalkylidene group of formula V (wherein q is 4-10)] in a specified equivalent ratio of units of formula II to units of formula III and has a specified intrinsic viscosity measured under specified conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an amorphous aromatic polyester, more specifically, an amorphous aromatic polyester which gives a molded article having excellent heat resistance, mechanical properties and solvent resistance by melt molding. The present invention relates to a method for efficiently producing polyester.

[0002]

2. Description of the Related Art Aromatic polyesters having various characteristics such as an amorphous polymer, a crystalline polymer or a liquid crystalline polymer can be obtained depending on the combination or composition of the constituent components. Among these, amorphous polymers are excellent in dimensional stability, transparency, mechanical properties, and heat resistance, and have been variously studied as so-called amorphous engineering plastics. Particularly, a polymer using terephthalic acid and isophthalic acid as the acid component and 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A) as the diol component has a relatively balanced physical property. However, this is being utilized for development, but this polymer, like ordinary amorphous polymers, has insufficient solvent resistance and is easily dissolved or swelled in various materials for bravery, and its application is limited. There is.

For the purpose of improving the solvent resistance, it has been proposed to use a part of hydroquinone as a diol component (Japanese Patent Application Laid-Open No. 52-78999). The hydroquinone component-introduced polymer is certainly improved in solvent resistance and stress crack resistance as compared with a polymer using bisphenol A alone as a diol component. However, the production method thereof is such that the hydroquinone component is extremely susceptible to oxidation, or the solubility of the polymer is insufficient. You cannot adopt legality.

Therefore, according to the above-mentioned Japanese Patent Application Laid-Open No. 52-78999, production by a melt polymerization method is tried as a production method of a polymer into which a hydroquinone component is introduced. However, in this method, as shown in the examples, the target aromatic polyester is produced by solidifying or crystallizing the polymer in the melt polymerization process and subsequently solid-phase polymerizing it. . This is because at a relatively low melt polymerization temperature of about 320 ° C. or less, the melt viscosity of the polymer is high, so that it is difficult to obtain a high degree of polymerization polymer capable of expressing sufficient toughness, and further, a polymer obtained by a hydroquinone component is This is considered to be due to the property that it can be crystallized. However, the method of using this solid-state polymerization in combination complicates the manufacturing process,
Moreover, there is a problem that productivity is low and cost is high.

Further, if a polymer is directly obtained from a dicarboxylic acid and a diol by such a melt polymerization method, it is not practical because the coloring is intense and the polymerization speed is low. Therefore, in practice, an alternative method to the method (1) in which the diaryl ester of the dicarboxylic acid component and the diol are reacted in advance, or the method (2) to react the dicarboxylic acid and the lower aliphatic carboxylic acid ester of the diol, and the method (2) As the method (3), a lower aliphatic carboxylic acid anhydride is added when the dicarboxylic acid and the diol are reacted. However, in the methods (1) and (2), the raw material has to be esterified in advance, which causes a high cost. Also,
In the methods (2) and (3), since a lower aliphatic carboxylic acid is generated during the reaction, the apparatus is easily corroded, and the obtained polymer has a problem that the terminal COOH concentration is high.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing an aromatic polyester polymer having an excellent color tone by a melt polycondensation reaction, which is extremely advantageous industrially. Further objects and advantages of the present invention will be apparent from the following description.

[0007]

The present invention provides the following formulas (I), (II) and (III)

[0008]

[Chemical 5]

[A ¹ and A ² in the above formula (III) each represent a phenylene group which may be substituted. X is

[0010]

[Chemical 6]

(R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms or 6 to 12 carbon atoms.
Represents an aryl group or an aralkyl group. ) Or

[0012]

[Chemical 7]

1, 1-cycloalkylidene represented by (q represents an integer of 4 to 10)] and is substantially composed of the respective components, and the content equivalents of the components (II) and (III) In the production of an aromatic polyester having a ratio of 40/60 to 80/20, isophthalic acid or an aromatic dicarboxylic acid (a) having an isophthalic acid as a main acid component, a hydroquinone (b) and optionally substituted The good phenols (c) are represented by the following formulas (1) and (2)

[0014]

## EQU3 ## 0.4 ≦ B / A ≦ 0.83 (1) C / A ≦ 30 (2) [wherein A is an aromatic dicarboxylic acid (a), B is a hydroquinone (b), C Is the number of moles of the phenol (c). ] At the same time, in the presence of a catalyst, the mixture is heated and melted to produce an esterified product having an esterification reaction rate of 50% or more, and then 0.7 to 1.0 mol relative to the unreacted COOH group. Equivalent amount of diaryl carbonate and the following formula (IV)

[0015]

Embedded image HO—A ¹ —X—A ² —OH (IV) [A ¹ , A ² and X are the same as those in the above formula (III). ] The dihydroxy compound (d) represented by the following formula (3)

[0016]

## EQU00004 ## 0.95.ltoreq. (B + D) /A.ltoreq.1.2 (3) [wherein A and B are the same as in the above equation (1). Also, D
Is the number of moles of the dihydroxy compound (d). ] In a proportion satisfying the above conditions, and further heat-melting reaction is performed, and an intrinsic viscosity of 0.3 or more (phenol / 1, 1,
1,2,2-Tetrachloroethane mixed solvent (weight ratio 60
/ 40) in 35 ° C.).

The content equivalent ratio of the components (II) and (III) is 40/60 to 80/20 in terms of molar ratio. If the mole fraction of component (II) is less than 40%, the solvent resistance of the resulting polymer will be reduced. On the other hand, when it is more than 80%, the obtained polymer tends to be crystalline, resulting in insufficient transparency.

The aromatic dicarboxylic acid (a) used in the method of the present invention is isophthalic acid or an aromatic dicarboxylic acid containing isophthalic acid as a main acid component. Other aromatic dicarboxylic acids used as a secondary acid component together with isophthalic acid include, for example, terephthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-
Preferred examples include dicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid and the like.

The secondary acid component may account for 20 mol% or less, preferably 10 mol% or less, of the wholly aromatic dicarboxylic acid.

In the present invention, the above compound (a),
(B) and (c) are the following two relational expressions.

[0021]

[Equation 5] 0.4 ≦ B / A ≦ 0.83 (1) C / A ≦ 30 (2) [wherein A is an aromatic dicarboxylic acid (a), B is a hydroquinone (b), C Is the number of moles of the phenol (c). ] Are used in a molar ratio such that
The above formula (1) represents the component (I
The content equivalent ratio of (I) and (III) is 40/60 to 80/20.
Is necessary to satisfy.

Preferred examples of the phenols (c) include phenol, m-cresol, p-cresol, p-butylphenol, p-aminophenol and o-phenylphenol.
Of these, phenol, cresol and o-phenylphenol are more preferable, and phenol is particularly preferable.

The main role of these phenols (c) is not to be a constituent of the wholly aromatic polyester polymer produced, but to act as a reaction medium at the initial stage of the reaction.

Therefore, it is not always necessary to use such phenols, but it is preferable to use phenols because the reaction is faster, the reaction product is less likely to decompose, and the coloring is small. The preferred amount of the phenols (c) used is such that the molar ratio (C / A) to the compound (a) is 3
The amount is 0 or less. Component (c) relative to component (a)
The molar ratio (C / A) of the use ratio of is particularly preferably 1 to 6.

In the method of the present invention, the above compound (a),
(B) and optionally (c) are heated and melted in the presence of a catalyst. The catalyst used here is not particularly limited, and conventionally known catalysts used in the production of polyester can be used, and examples thereof include sodium, potassium, tin,
Carriers of metals such as antimony, strontium, zinc, cobalt, nickel, titanium, germanium, oxides, hydroxides, halides, inorganic and organic hydrochloric acids,
Complex salts and the like can be mentioned. Particularly, antimony compounds, tin compounds and titanium compounds are preferable. The amount of the catalyst used is not particularly limited, but is 0.0001 relative to the component (a).
It is preferable to set the dormitory at about 0.1 mol%.

In the present invention, after producing an esterified product having an esterification reaction rate of 50% or more, 0.7 to 1 molar equivalent of the diaryl carbonate and the dihydroxy compound (d) relative to the unreacted carboxylic acid residue. Is an important feature.

Examples of the diaryl carbonate include diphenyl carbonate, di-p-tolyl carbonate, dinaphthyl carbonate, di-p-chlorophenyl carbonate, phenyl-p-tolyl carbonate, etc. Of these, diphenyl carbonate is particularly preferred. . The diaryl carbonate may be used alone or in combination of two or more kinds.

The dihydroxy compound (d) added after the esterification product having an esterification reaction rate of 50% or more is represented by the following formula (IV)

[0029]

HO-A ¹ -X-A ² -OH (IV) [A ¹ , A ² and X are the same as those in the above formula (III). ] And A ¹ and A ² in the formula are each an optionally substituted phenylene group. X is

[0030]

[Chemical 10]

(R ¹ and R ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms or 6 to 12 carbon atoms.
Represents an aryl group or an aralkyl group. ) Or

[0032]

[Chemical 11]

A 1,1-cycloalkylidene group represented by (q represents an integer of 4 to 10) is shown.

Examples of dihydroxy compounds are 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane and 2,2-
Bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (3
5-dichloro-4-hydroxyphenyl) propane and the like are exemplified.

If the dihydroxy compound (d) is added before the formation of an esterified product having an esterification reaction rate of 50% or more, the dihydroxy compound (d) is easily decomposed during the polymerization to cause the branching of the polymer or the coloring of the polymer to be severe. , Not preferable.

In the present invention, the dihydroxy compound (D) is represented by the following formula (3)

[0037]

## EQU00006 ## 0.95.ltoreq. (B + D) /A.ltoreq.1.2 (3) [wherein A and B are the same as those in the above formula (1). Also, D
Is the number of moles of the dihydroxy compound (d). ] It is used in a molar ratio satisfying.

In the above formula (3), the aromatic dicarboxylic acid (a) and the dihydroxy compound [that is, the hydroquinone (b) and the compound (d) represented by the above formula (IV)] form a polymer segment. It indicates that the proper balance should be used. That is, when the above equation (3) is not satisfied, the degree of polymerization of the polymer is difficult to increase, and coloring or the like is likely to occur during the polymerization.

In the present invention, an esterification reaction and a transesterification reaction can proceed during heating and melting to produce an aromatic polyester polymer. Hereinafter, the heating and melting reaction will be described separately for the initial reaction before the addition of the diaryl carbonate and the dihydroxy compound (d) and the polymerization reaction after the addition.

In the initial reaction, at least 50% of the carboxyl groups of the aromatic dicarboxylic acid (a) are reacted with a hydroxy component [ie, hydroquinone (b), and optionally further phenols (c)] to esterify. It is a stage. At this stage, water is produced by the reaction and is distilled out of the reaction system. At this stage, it is necessary to prevent the hydroxy component from being distilled out of the reaction system.

The reaction temperature of the initial reaction varies depending on the catalyst, but is preferably 150 ° C. or higher. The temperature is more preferably 180 ° C or higher, and particularly preferably 200 ° C or higher. In addition, the reaction temperature is preferably raised as the reaction progresses. In this case, the preferable upper limit is 330 ° C, and more preferably about 300 ° C.

The initial reaction can usually be carried out under normal pressure to increased pressure. Hydroquinone (b), phenols (c)
When the reaction temperature is higher than the boiling point of, the reaction is preferably carried out under pressure. The reaction system is preferably in an atmosphere of an inert gas such as nitrogen or argon.

The reaction time may be a time sufficient for the esterification reaction to proceed sufficiently, and this time also varies depending on the reaction conditions, reaction scale and the like. It is preferably 30 minutes to 20 hours, more preferably about 1 to 10 hours.

In the above reaction, water generated by esterification is preferably removed outside the reaction system. The esterification reaction is an equilibrium reaction, and the reaction proceeds as the produced water is removed to the outside of the system to improve the yield and purity of the product. The generated water can be removed to the outside of the reaction system by the boiling point difference with the phenols (c), but can also be removed to the outside of the reaction system by azeotropic distillation using an organic solvent that forms an azeotropic mixture with water. it can. 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 ethylenebenzene can be preferably used. The reaction rate of the esterification reaction in the initial reaction needs to be 50% or more. This esterification reaction rate can be known by the amount of water produced by the reaction, but in order to obtain it more accurately, it can be known by taking out a part of the reaction product and measuring the unreacted COOH value. . The ester Tsutsu in the initial reaction is preferably 60 to 95%, more preferably 70 to 95%.
95%.

After the above initial reaction, the amount of diaryl carbonate added is determined based on the amount of water produced or the unreacted COOH value. In terms of accuracy, unreacted C
It is preferably determined from the OOH value.

The amount of diaryl carbonate added is 0.7 to 1.0 molar equivalent with respect to the unreacted COOH. More preferably, it is 0.75-0.95 molar equivalent. 0.7
If the amount is less than the molar equivalent, the effect of adding diaryl carbonate is small, and if the amount is more than 1.0 molar equivalent, many carbonate bonds are likely to remain in the polymer, which causes coloring and solidification during polymerization, which is not preferable. This diaryl carbonate is consumed in the next polymerization reaction, supplements the unreacted esterification rate, and allows the polymerization reaction to proceed smoothly, thus greatly contributing to obtaining a good polymer.

The method for adding the diaryl carbonate and the dihydroxy compound (d) is not particularly limited after the initial reaction and may be charged after the temperature is lowered, or the diaryl carbonate may be added to the reaction system at the initial reaction temperature. It is preferable to perform it under the condition that air and the like are not mixed.

The next polymerization reaction is a stage in which, at the same time that the esterification proceeds further, the reaction between the ester produced up to that time and the hydroxy component and the diaryl carbonate proceeds and the polymerization proceeds. At this stage, carbon dioxide, water and phenols are produced. Water and phenols should be distilled out of the reaction system. At this stage, the diaryl carbonate reacts with unreacted COOH to generate carbon dioxide, water, and phenols, which helps improve the esterification rate. Further, in this reaction, the sublimate having a high melting point is suppressed, and the polymerization reaction proceeds more smoothly.

The reaction temperature in the polymerization reaction is preferably from the initial reaction temperature to 380 ° C. In the method of the present invention, it is necessary to carry out the polymerization reaction while the polyester is melted. Since the viscosity of the reaction product increases as the polymerization progresses, it is preferable to perform the heating while gradually increasing the temperature. For example, when the intrinsic viscosity of the polymer is about 0.5, it is preferably about 230 to 320 ° C. It is carried out at temperature. When the intrinsic viscosity is higher than that, preferably 320
Melt polymerization is carried out at a temperature of ˜380 ° C., more preferably 320˜350 ° C. At this time, the phenols (c) are recovered and reused.

When the degree of polymerization of the aromatic polyester obtained by the method of the present invention is increased, it may be carried out in an extruder type reactor or the like.

The polymerization reaction is carried out under reduced pressure or by passing an inert gas, and water and phenols resulting from the reaction and, if necessary, an excess of the dihydroxy aromatic compound,
It is advantageous to carry out the removal forcibly outside the reaction system.

The polyester obtained by the present invention has an intrinsic viscosity of 0.3 or more measured at 35 ° C. in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40). is necessary. When the intrinsic viscosity is lower than 0.3, the heat resistance and toughness of the obtained polymer are insufficient, which is not preferable. Intrinsic viscosity 0.4-2.0
Is preferable, and 0.5 to 1.5 is particularly preferable.

The aromatic polyester obtained by the present invention is an amorphous polymer, and a transparent molded product can be obtained by melt molding such as injection molding. Further, the fact that the polymer obtained by the present invention is amorphous can be confirmed, for example, by the fact that its melting point cannot be obtained by DSC.

The aromatic polyester obtained by the present invention may be added with various stabilizers such as an oxidation stabilizer and an anti-coloring agent, and various additives such as a colorant, a pigment and a lubricant, if necessary. Absent.

[0055]

As described above, according to the method for producing an aromatic polyester of the present invention, an inexpensive raw material is used, and the excellent transparency as in the case of using an expensive raw material only by melt polymerization, It is possible to produce aromatic polyesters having a color tone. Therefore, when the aromatic polyester produced by the production method of the present invention is used as a resin raw material, the molded product can be colored in various ways due to its transparency and good color tone. Further, when an aromatic polyester is directly produced from a dicarboxylic acid and a diol without adding diaryl carbonate in the middle, a high melting point sublimate is produced in an amount of about 2 to 3 kg per 50 kg of the polymer, and the coloring of the polymer is large. According to the production method of 1, the amount of the high melting point sublimate is small, the effect on the polymerization reaction is large, and the coloring of the polymer is small. Further, by controlling the addition amount of the diaryl carbonate, unreacted COOH groups, which are often problematic in polyester, can be greatly reduced, so that hydrolysis resistance and the like can be improved. From the above, the industrial significance of the present invention is extremely large.

[0056]

EXAMPLES The present invention will be described in detail below with reference to examples. In the examples, “parts” means “parts by weight”. The intrinsic viscosity was measured in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40) at a concentration of 1.2 g / dl and a temperature of 35 ° C. The thermal characteristics of the polymer were measured by DSC at a temperature rising rate of 10 ° C./min.

[0057]

Example 1 166 parts isophthalic acid, hydroquinone 8
0.4 parts, phenol 188 parts, antimony trioxide 0.
09 parts were charged into a reactor equipped with a stirrer and a distillation system,
The system was purged with nitrogen and then heated to 280 ° C. under nitrogen pressure.
The reaction was carried out for 10 hours while gradually lowering the pressure from 8 kg / cm ² to 2 kg / cm ² and distilling the water generated by the reaction out of the system. During this period, 26 parts of water was produced (esterification reaction rate 72%). After that, unreacted phenol was driven out of the system. After cooling the reaction mixture, the terminal COOH group was measured to be 1587 (equivalent / t).
(Esterification reaction rate calculated value was 75%). Then
The reaction system is returned to normal pressure, and diphenyl carbonate 85.7
And 20.8-bis (4-hydroxyphenyl) propane (70.8 parts) were added, and the mixture was allowed to react for 150 minutes while distilling volatile components out of the system in a nitrogen stream. During this period, the reaction temperature was increased from 250 ° C to 300 ° C. Next, the pressure inside the system was gradually reduced to 40 mmHg over 30 minutes. After setting the reaction temperature to 340 ° C., 1 hour later, it was placed in a high vacuum of about 0.5 mmHg and further reacted for 1 hour to obtain a polymer. The high melting point sublimate produced at this time was 2.2 parts. The obtained polymer was light yellow and transparent. The polymer obtained has an intrinsic viscosity of 0.65 and a glass transition temperature of 176 ° C.
Met. No melting point was observed by DSC.

[0058]

Comparative Example 1 The reaction was performed in the same manner as in Example 1 except that diphenyl carbonate was not added after the initial reaction. At this time, 12.6 parts of a high melting point sublimate was produced. The obtained polymer was dark brown. The polymer obtained had an intrinsic viscosity of 0.45 and a glass transition temperature of 172 ° C. No melting point was observed by DSC.

[0059]

Example 2 2,2-bis (4-hydroxyphenyl)
The reaction was performed in the same manner as in Example 1 except that 80.5 parts of 1,1-bis (4-hydroxyphenyl) cyclohexane was added instead of 70.8 parts of propane. At this time, the amount of the high-melting point sublimate was 1.9 parts. The obtained polymer was light yellow and transparent. The intrinsic viscosity of the obtained polymer is 0.
65, the glass transition temperature was 184 ° C. No melting point was observed by DSC.

Claims (1)

[Claims] 1. A composition substantially composed of the respective components of the following formulas (I), (II) and (III), and further comprising the components (II) and (III)
In producing an aromatic polyester having a content equivalent ratio of) of 40/60 to 80/20, [A ¹ and A ² in the above formula (III) are each a phenylene group which may be substituted. X is (R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, or an aryl group or aralkyl group having 6 to 12 carbon atoms. ) Or (Q represents an integer of 4 to 10) 1,1
-Indicates cycloalkylidene. ] Isophthalic acid or aromatic dicarboxylic acid (a) mainly containing isophthalic acid, hydroquinone (b) and optionally substituted phenols (c) are represented by the following formulas (1) and (2) ## EQU1 ## 0.4 ≦ B / A ≦ 0.83 (1) C / A ≦ 30 (2) [wherein A is aromatic dicarboxylic acid (a), B is hydroquinone (b), C Is the number of moles of the phenol (c). ] At the same time, in the presence of a catalyst, the mixture is heated and melted to produce an esterified product having an esterification reaction rate of 50% or more, and then 0.7 to 1.0 mol relative to the unreacted COOH group. An equivalent amount of diaryl carbonate and the following formula (IV): HO—A ¹ —X—A ² —OH (IV) [A ¹ , A ² and X are the same as those in the above formula (III). And a dihydroxy compound (d) represented by the following formula (3): 0.95 ≦ (B + D) /A≦1.2 (3) [wherein A and B are the above formula (1)] Is the same as. Also, D
Is the number of moles of the dihydroxy compound (d). ] In a proportion satisfying the above conditions, and further heat-melting reaction is performed, and an intrinsic viscosity of 0.3 or more (phenol / 1, 1,
1,2,2-Tetrachloroethane mixed solvent (weight ratio 60
/ 40) in 35 ° C.).