JPH07292089A - Production of lowly colored polyester - Google Patents

Abstract

PURPOSE:To obtain a lowly colored polyester by reacting a dialkyl dicarboxylate with a polycarbonate and/or an aromatic dialkyl dicarbonate in the presence of a Zn catalyst. CONSTITUTION:A dialkyl dicarboxylate (e.g. dimethyl terephthalate) is reacted with (B) a polycarbonate and/or an aromatic dialkyl dicarbonate (e.g. dimethyl carbonate derived from bisphenol A) in the presence of a Zn catalyst to obtain a lowly colored polyester. Examples of the catalyst include zinc chloride, zinc sulfide, zinc carbonate, and zinc alkoxides. The amount of the catalyst is desirably about 0.0001-10 pts.wt. per 100 pts.wt. the ingredient (B). The polyester is excellent in heat resistance, stress cracking resistance, etc., and hence suited for use in electrolysis, the automotive field, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing polyester. More specifically, it relates to a method for producing a low-colored polyester, which comprises using a Zn-based catalyst as a reaction catalyst when producing a polyester by reacting a dialkyl ester of dicarboxylic acid with a polycarbonate and / or an aromatic dialkyldicarbonate. .

[0002]

2. Description of the Related Art Various methods for producing thermoplastic polyesters are known, but the most general method is a melt polycondensation reaction of a dicarboxylic acid and a diol in the presence of a catalyst. However, although the method is effective for producing a polyester using an aliphatic diol represented by ethylene glycol or the like as a diol, 2,2'-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A is described. In the production of polyester using an aromatic diol represented by
Aromatic diols have poor reactivity, and when trying to obtain a polyester having a high degree of polymerization, a reaction under severe conditions is required, resulting in a problem that the resulting polymer is severely colored.

In order to avoid such problems, JP-A-5-262864 discloses a method for producing an aromatic polyester in which a dialkyl ester of an aromatic dicarboxylic acid is reacted with an aromatic polycarbonate and / or an aromatic dialkyl dicarbonate. Is described. However, in the method of the above-mentioned patent, although the reaction conditions are mild, there is a problem in that when the disclosed Ti or Zr-based catalyst is used, the polyester produced is severely colored. In addition, when a Li-based catalyst is used, coloring is reduced, but there is a problem that it is difficult to increase the molecular weight due to the influence of water and the like. For this reason, it is necessary to control the water content of the raw material / reactor to suppress side reactions, which is a constraint on the manufacturing process.

[0004]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the conventional methods for producing polyesters,
The purpose of the present invention is to provide a new method for producing a low-colored polyester.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies to achieve the above object, the present inventors have found that in the reaction of a dialkyl ester of dicarboxylic acid with a polycarbonate and / or an aromatic dialkyl dicarbonate, a Zn-based catalyst is used. It was found that a polyester having no side reaction and a greatly reduced coloration can be produced by using, and the object thereof can be achieved, and the present invention has been completed.

That is, according to the present invention, when a polyester is produced by reacting a dialkyl ester of a dicarboxylic acid with a polycarbonate and / or an aromatic dialkyl dicarbonate, a Zn-based catalyst is used to produce a low-colored polyester. The method is the content.

The present invention will be described in detail below. In the present invention, examples of the polycarbonate used as a raw material include compounds represented by the general formula (I).

[0008]

[Chemical 4]

[In the general formula (I), R ¹ is a divalent aromatic hydrocarbon group, R ² —X—R ³ group (provided that R ² and R ³ are 2
It is a valent aromatic hydrocarbon group, and X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And a represents a positive integer of 1 to 500. Among the polycarbonates used in the present invention, a polycarbonate based on bisphenol A is preferable from the viewpoint of balance between physical properties and cost.

As the aromatic dialkyl dicarbonate used as a raw material in the present invention, compounds represented by the general formula (II) can be mentioned.

[0011]

[Chemical 5]

[R ⁴ in the general formula (II) is a divalent aromatic hydrocarbon group, R ⁶ -X-R ⁷ group (provided that R ⁶ and R ⁷ are 2
It is a valent aromatic hydrocarbon group, and X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And R ⁵ is an aliphatic hydrocarbon group (preferably having 1 carbon atom). To 4) or an aromatic hydrocarbon group (preferably having 6 to 10 carbon atoms). ]

Specific examples of such compounds include the following aromatic diols dimethyl, diethyl and diphenyl carbonate. That is, as specific examples of the aromatic diol, for example, bisphenol A, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4
-Hydroxy-3,5-dichlorophenyl) methane,
1,1-bis (4-hydroxyphenyl) cyclohexylmethane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) 1-phenylethane, 1,1-bis (4 -Hydroxyphenyl) -3,3,5-trimethylcyclohexane, 4,
4'-dihydroxydiphenyl ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxy-3,5-dimethylphenyl) sulfone, 4,
4'-dihydroxybenzophenone, 2,2-bis (4
-Hydroxy-3,5-dimethylphenyl) propane,
Tetrabromobisphenol A, tetrachlorobisphenol A, dihydroxydiphenyl, hydroquinone,
Examples thereof include resorcinol, dihydroxynaphthalene, dihydroxyanthracene, phenolphthalein, ferulescein, 2,2′-dihydroxy-1,1-dinaphthylmethane, 4,4′-dihydroxydinaphthyl and the like. Of these, bisphenol A is easily available.
Dimethyl carbonate is preferred. In the present invention, the above-mentioned polycarbonate and aromatic dialkyl dicarbonate may be used alone or in combination of two or more kinds, or may be used in combination of one kind or two or more kinds.

In the present invention, the dialkyl ester of dicarboxylic acid used as another raw material is
The compound represented by general formula (III) can be mentioned.

[0015]

[Chemical 6]

[R ⁸ in the general formula (III) is a divalent aromatic hydrocarbon group (provided that the hydrogen atom of the aromatic ring is substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like). Or an aliphatic or alicyclic hydrocarbon group, and R ⁹ is an aliphatic hydrocarbon group (preferably having 1 carbon atom).
To 4) or an aromatic hydrocarbon group (preferably having a carbon number of 6 to 1)
0) is shown. ]

Specific examples of the dialkyl ester of dicarboxylic acid include dimethyl, diethyl and diphenyl esters of dicarboxylic acid shown below. That is, specific examples of the dicarboxylic acid include terephthalic acid, methoxyterephthalic acid, ethoxyterephthalic acid, fluoroterephthalic acid, chloroterephthalic acid, methylterephthalic acid, isophthalic acid, phthalic acid, methoxyisophthalic acid, diphenylmethane-4,4'-. Dicarboxylic acid, diphenylmethane-3,3'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl-4,
4'-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, adipic acid,
Sebacic acid, azelaic acid, suberic acid, dodecane dicarboxylic acid, 3-methyl azelaic acid, glutaric acid, succinic acid, cyclohexane-1,4-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, cyclopentane-
1,3-dicarboxylic acid and the like can be mentioned. These may be used alone or in combination of two or more. Among these, it is particularly preferable to use one or more dimethyl esters of terephthalic acid, isophthalic acid, cyclohexane-1,4-dicarboxylic acid, and cyclohexane-1,3-dicarboxylic acid in terms of physical properties and cost. .

The method for producing a polyester of the present invention is characterized by reacting a polycarbonate and / or an aromatic dialkyl dicarbonate with a dialkyl ester of a dicarboxylic acid in the presence of a Zn-based catalyst. As the Zn-based catalyst used in this reaction, any catalyst containing a Zn element can be used. Further, the catalyst is not limited to the anhydride, and a hydrate or the like may be used. Specific examples of such Zn-based catalysts include zinc halides such as zinc chloride, zinc bromide, zinc iodide, zinc, zinc carbonate,
Examples thereof include zinc sulfide, zinc carboxylate, zinc alkoxide, and zinc phenoxide, which may be used alone or in combination of two or more. Among these, especially zinc carboxylate, zinc carbonate, zinc halide and these 2
Mixtures of one or more are preferred. The amount of Zn-based catalyst used in these is not particularly limited, but from the balance of reactivity and physical properties,
0.0001 to 10 parts by weight based on 100 parts by weight of polycarbonate and / or aromatic dialkyl dicarbonate,
Preferably 0.001 to 5 parts by weight, more preferably 0.1.
005 to 0.5 parts by weight are used.

The method for producing the polyester of the present invention may be either a batch method or a continuous method. In the method for producing a polyester of the present invention, the amount of polycarbonate and / or aromatic dialkyl dicarbonate and dialkyl ester of dicarboxylic acid used is 1: 1 in terms of molar ratio.
The range of 0.5 to 1: 2.0 (polycarbonate and / or aromatic dialkyl dicarbonate: dialkyl ester of dicarboxylic acid) is preferable, and more preferably 1:
0.8 to 1: 1.5, more preferably 1: 1 to
The range is 1: 1.4. When the amount of the dialkyl ester of dicarboxylic acid used is less than the equivalent amount, ester carbonate is produced, and when it is more than the equivalent amount, polyester is produced. If the range is less than 1: 0.5, the heat resistance, which is a characteristic of polyarylate, decreases, and if the range exceeds 1: 2.0, the dicarboxylic acid dialkyl ester is used in a large excess, resulting in cost reduction. It is not preferable in terms of aspect.

In the present invention, it is preferable to carry out the reaction in two steps at different temperatures. In the first step, 2
The heating is performed at 00 to 300 ° C, more preferably 250 to 300 ° C. In this step, the polycarbonate is depolymerized by a transesterification reaction to produce a dialkyl carbonate. In the second step, heating is performed at 280 to 350 ° C., more preferably 300 to 350 ° C. under reduced pressure (0.05 to 1.0 Torr). In this step, a high molecular weight polyester is obtained by removing the remaining portion of the produced dialkyl carbonate. However, the present invention is not limited to the reaction in the above two-step process, and the reaction may be carried out at multi-step temperature and reduced pressure, or may be carried out under the same temperature condition throughout the reaction. .

In the present invention, suitable cosolvents such as diphenyl ether, substituted cyclohexane,
Decahydronaphthalene or the like may be used. Further, in the present invention, various compounds may be added to impart various properties. For example, it is possible to use a branching agent or the like to adjust the viscosity. Further, in order to obtain a low-colored polyester, for example, an antioxidant may be added.

Generally, the weight average molecular weight of the polyester obtained in the present invention is 3000 to 15 in terms of polystyrene.
The range of 0000 is preferable, and 30,000 to 100,000
Is more preferable. The polyester obtained in the present invention may also contain dyes, pigments, stabilizers, flameproofing agents, flame retardants, fillers, and reinforcing substances such as glass fibers, carbon fibers, or other auxiliaries. The amount added is appropriately determined depending on the intended use. The polyesters obtained according to the invention are preferably used for the production of shaped articles, fibers, filaments and films. The polyester obtained by the present invention has high heat resistance, strength (toughness), hydrolysis resistance, creep resistance,
Since it has stress cracking resistance and the like, it is particularly suitable for articles in fields where these are required, for example, electric fields, lighting fields, and automobile fields.

[0023]

EXAMPLES The present invention will be described in more detail based on the following examples, but the present invention is not limited to the following examples, and various modifications can be made without departing from the scope of the invention. The properties of the polymer were measured according to the methods described below. (1) Weight average molecular weight of polymer [Mw] A 510 type GPC system manufactured by Waters was used, and the column temperature was 3 at a polymer concentration of 2 mg / ml in a chloroform solvent.
It was measured at 5 ° C. The weight average molecular weight was calculated using polystyrene as a standard sample. (2) Glass transition temperature [Tg] of polymer It was measured using a DSC-7 differential scanning calorimeter manufactured by Perkin-Elmer under a nitrogen stream at a temperature rising rate of 20 ° C / min. (3) Yellowness Index [YI] of Polymer Using JIS Z80 color difference meter manufactured by Nippon Denshoku Industries Co., Ltd., JIS K
It was measured by a transmission method based on 7013.

Example 1 In a glass reaction vessel equipped with a stirring blade, a nitrogen inlet, a pressure reducing port and a distillation port, 254 g of polycarbonate (manufactured by Teijin Limited, Panlite L-1250W, Mv = 25000) and 97 g of dimethyl terephthalate (0 0.5 mol), dimethyl isophthalate 97 g (0.5 mol), and zinc acetate dihydrate 2.19 g (10 mmol) were charged, and after nitrogen substitution, heated to 280 ° C. in an oil bath in a nitrogen flow state. did. The temperature was maintained as it was for 1 hour, and then the temperature was raised to 300 ° C. over 20 minutes. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. Outflow amount is 45
g (50% of theory). The pressure of the reaction system was gradually reduced (1 Torr in 30 minutes), the temperature was raised to 320 ° C., and the temperature was maintained for 3 hours. After the stirring was stopped, the reaction mixture was poured out to obtain 354 g of a pale yellow polymer. The molecular weight (weight average molecular weight) of the obtained polymer was 460 by GPC measurement.
00 (in terms of polystyrene), the glass transition temperature was 185 ° C. from DSC measurement. The yellowness index (Y.I.) of the 1/8 inch molded product of the obtained polyester is 23.
Met.

Example 2 Example 2 was repeated except that the catalyst was changed to zinc carbonate. The molecular weight (weight average molecular weight) of the obtained polymer is G
The PC measurement showed 45000 (in terms of polystyrene), and the glass transition temperature was 184 ° C. according to the DSC measurement. The yellowness index (Y.I.) of the obtained polyester 1/8 inch molded product was 28.

Relatively 1 catalyst to Ti (OBu) ₄ The procedure was the same as in Example 1 except for the changes. The molecular weight (weight average molecular weight) of the obtained polymer was 50,000 (in terms of polystyrene) by GPC measurement, and the glass transition temperature was 191 ° C. by DSC measurement. The yellowness index (Y.I.) of the obtained polyester 1/8 inch molded product was 98.

Example 3 344 g (1.0 mol) of bisphenol A dimethyl dicarbonate having the following structural formula and dimethyl terephthalate 97 g (0 0.5 mol), dimethyl isophthalate 97 g (0.5 mol), and zinc acetate dihydrate 2.19 g (10 mmol) were charged, and after nitrogen substitution, heated to 280 ° C. in an oil bath in a nitrogen flow state. did. The temperature was maintained as it was for 1 hour, and then the temperature was raised to 300 ° C. over 20 minutes. Dimethyl carbonate produced over 1 hour was distilled from the distillation port. Outflow amount is 41g
(45% of theory). The reaction system is gradually depressurized (3
It was set to 1 Torr in 0 minutes, and the temperature was raised to 320 ° C.
Held for hours. After the stirring was stopped, the reaction mixture was discharged and 3
48 g of a pale yellow polymer was obtained. The molecular weight (weight average molecular weight) of the obtained polymer was 45,000 as measured by GPC.
The glass transition temperature (in terms of polystyrene) was 184 ° C. according to the DSC measurement. In addition, 1 of the obtained polyester
The yellowness index (Y.I.) of the / 8 inch molded product was 26.

[0028]

[Chemical 7]

Example 4 254 g of polycarbonate (Panlite L-1250W, Mv = 25000, manufactured by Teijin Ltd.) and 97 g of dimethyl terephthalate (0 0.5 mol), dimethyl isophthalate 97 g (0.5 mol) and zinc acetate dihydrate 2.19 g (10 mmol) were charged, and after nitrogen substitution, heated to 320 ° C. in an oil bath in a nitrogen flow state. did. The temperature was maintained for 1 hour. Thereafter, the dimethyl carbonate produced over 1 hour was distilled from the distillation port. The amount of outflow was 52 g (58% of theory).
The reaction system was gradually depressurized at a temperature of 320 ° C (1 Torr in 30 minutes).
r) and kept as such for 3 hours. After the stirring was stopped, the reaction mixture was poured out to obtain 350 g of a pale yellow polymer.
The molecular weight (weight average molecular weight) of the obtained polymer is GPC.
From the measurement, it was 49000 (in terms of polystyrene), and the glass transition temperature was 190 ° C. from the DSC measurement. The yellowness index (Y.I.) of the obtained polyester 1/8 inch molded product was 30.

[0030]

As described above, according to the present invention,
A polyester having a low degree of coloring can be manufactured by a simple method.

Claims (18)

[Claims] 1. A dialkyl ester of dicarboxylic acid,
When a polyester is produced by reacting a polycarbonate and / or an aromatic dialkyl dicarbonate, Z
A method for producing a low-colored polyester, which comprises using an n-based catalyst. 2. The Zn-based catalyst is at least one zinc compound selected from the group consisting of zinc, zinc carboxylate, zinc carbonate, zinc halide, zinc sulfide, zinc alkoxide and zinc phenoxide. Manufacturing method. 3. The method according to claim 1, wherein the amount of the Zn-based catalyst used is 0.0001 to 10 parts by weight based on 100 parts by weight of the polycarbonate and / or the aromatic dialkyl dicarbonate. 4. The method according to claim 3, wherein the amount of the Zn-based catalyst used is 0.001 to 1 part by weight based on 100 parts by weight of the polycarbonate and / or the aromatic dialkyl dicarbonate. 5. The method according to claim 4, wherein the amount of the Zn-based catalyst used is 0.005 to 0.5 part by weight based on 100 parts by weight of the polycarbonate and / or the aromatic dialkyl dicarbonate. 6. The production method according to claim 1, wherein the reaction is performed by increasing the degree of reduced pressure in the latter half of the reaction. 7. The method according to claim 1, wherein the polycarbonate is represented by the following general formula (I). [Chemical 1] [R ¹ in the general formula (I) is a divalent aromatic hydrocarbon group, R 1
² -X-R ³ group (wherein, R ² and R ³ is a divalent aromatic hydrocarbon group, X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And a represents a positive integer of 1 to 500. ] 8. The production method according to claim 1, wherein the aromatic dialkyl dicarbonate is represented by the following general formula (II). [Chemical 2] [R ⁴ in the general formula (II) is a divalent aromatic hydrocarbon group, R 4
⁶ -X-R ⁷ group (wherein, R ⁶ and R ⁷ is a divalent aromatic hydrocarbon group, X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And R ⁵ is an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Indicates. ] 9. R ⁴ in the general formula (II) is a divalent aromatic hydrocarbon group, R ⁶ —X—R ⁷ group (provided that R ⁶ and R ⁷ are 2
It is a valent aromatic hydrocarbon group, and X represents an oxygen atom, a sulfonyl group, a carbonyl group, a hydrocarbon group, an ester group or a direct bond. (However, the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like.), And R ⁵ has 1 to 4 carbon atoms.
9. The production method according to claim 8, which is an aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 10 carbon atoms. 10. The method according to claim 1, wherein the dialkyl ester of dicarboxylic acid is represented by the following general formula (III). [Chemical 3] [R ⁸ in the general formula (III) is a divalent aromatic hydrocarbon group (provided that the hydrogen atom of the aromatic ring is a halogen atom, a hydrocarbon group,
It may be substituted with an alkoxy group or a phenoxy group. ), An aliphatic or alicyclic hydrocarbon group, and R ⁹ represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ] 11. R ⁸ in general formula (III) has 6 to 1 carbon atoms.
A divalent aromatic hydrocarbon group of 0 (provided that the hydrogen atom of the aromatic ring may be substituted with a halogen atom, a hydrocarbon group, an alkoxy group, a phenoxy group or the like), and a carbon number of 1 to 2.
The production method according to claim 10, which is an aliphatic or alicyclic hydrocarbon group having 0, and R ⁹ is an aliphatic hydrocarbon group having 1 to 4 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. 12. The production method according to claim 7, wherein R ¹ in the general formula (I) has a structure derived from 2,2′-bis (4-hydroxyphenylpropane). 13. The method according to claim 8 or 9, wherein R ⁴ in the general formula (II) has a structure derived from 2,2′-bis (4-hydroxyphenylpropane). 14. The method according to claim 1, wherein the dialkyl ester of dicarboxylic acid is dimethyl terephthalate and / or dimethyl isophthalate. 15. The method according to claim 1, wherein the dialkyl ester of dicarboxylic acid is dimethyl-1,4-cyclohexanedicarboxylate and / or dimethyl-1,3-cyclohexanedicarboxylate. 16. The amount of dialkyl ester of dicarboxylic acid used is 50 to 200 mol% based on the amount of polycarbonate and / or aromatic dialkyl dicarbonate used.
The manufacturing method according to claim 1, wherein 17. The amount of dialkyl ester of dicarboxylic acid used is 80 to 150 mol% with respect to the amount of polycarbonate and / or aromatic dialkyl dicarbonate used.
The manufacturing method according to claim 16, wherein 18. The method according to claim 17, wherein the amount of the dialkyl ester of dicarboxylic acid used is 100 to 140 mol% with respect to the amount of the polycarbonate and / or the aromatic dialkyl dicarbonate used.