JP2828182B2 - Production method of aromatic copolyester - Google Patents

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 a thermotropic aromatic copolyester which can be melt-processed at a relatively low temperature.

[0002]

2. Description of the Related Art In recent years, various engineering plastics have been developed, and liquid crystal copolymers having optical anisotropy have attracted particular attention. Adv
ances in Polymer Science
60/61 p. 61 1984 describes a homopolymer of P-hydroxybenzoic acid and a copolymer of terephthalic acid and hydroquinone. However, these polymers have a high melting point of 610 ° C. and 596 ° C., respectively. It is difficult to melt-process without decomposition.
Japanese Patent Publication No. 47-47870 discloses a copolymer of P-hydroxybenzoic acid, terephthalic acid and hydroquinone. This copolymer has a high melting point of 500 ° C. or more and is extremely difficult to melt-process. Have difficulty.

[0003] Various proposals have been made on methods for improving the melt processability by lowering the melting point of liquid crystal copolyester (Brit. Polymer Journal 132).
1980), and in particular, JP-A-64-66231 discloses a method using 2,2′-dimethylbiphenyl-4,4′-dicarboxylic acid as a comonomer component. Makromolecules, vol. 20 On page 2374, 1987, as a comonomer component,
2,2'-bis (trifluoromethyl) -biphenyl-
The use of 4,4'-dicarboxylic acid as a monomer is described. However, 2,2'-disubstituted biphenyl-
4,4'-dicarboxylic acids interfere with the coplanarity of the phenyl ring, thus reducing the crystallinity of the polymer. In general, it has been pointed out that a polymer having low crystallinity does not have a satisfactory mechanical strength.

[0004] The present applicant discloses that 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid and 3,4'-dimethylbiphenyl-4,3'-dicarboxylic acid are melted at a relatively low temperature using a comonomer component. Processable aromatic copolyesters are disclosed in Japanese Patent Application Nos. 2-110151 and 2-19.
No. 3943. The proposed aromatic copolyester has a melting point that can be melt-molded without excessive loss of crystallinity.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have studied the method for producing the above-mentioned aromatic copolyesters. As a result, the present inventors have used aromatic oxycarboxylic acid compounds and aromatic dihydroxy compounds as raw materials, ,
By adding an aromatic dicarboxylic acid compound and performing polycondensation, a monomer component is randomly introduced into the polymer, and it is investigated that an aromatic copolyester having excellent heat resistance and excellent mechanical strength can be obtained. The present production method has been provided.

[0006]

The present invention provides an alkanoylation of an aromatic oxycarboxylic acid compound (I) represented by the following formula A and an aromatic dihydroxy compound (III) represented by the following formula E: The pre-condensation is carried out by contacting with an alkanoylating agent and further performing a reaction at 150 to 260 ° C., and then converting the pre-condensate to an aromatic dicarboxylic acid compound (II) represented by the following formulas B, C and D: And add

Embedded image The polycondensation at a temperature in the range of 200 to 350 ° C., and the molar ratio of each compound to be subjected to the polycondensation reaction is defined as (I) /
[(I) + (II)] = 1/100 to 85/100,
(II) / (III) = 1 to 1.1, and the proportion of the compound (B + C) in the aromatic dicarboxylic acid compound (II) is at least 5 mol%, Production method (where R is a hydrogen atom,
It represents an alkyl group or an aryl group having 1 to 8 carbon atoms, or a halogen atom. )I will provide a.

In the alkanoylation and precondensation of formulas A and E, alkanoylating agents include, for example,
Acetic anhydride, propionic anhydride and the like can be used, but acetic anhydride is particularly preferred. The amount of the alkanoylating agent used is from 1 to
1.2 equivalents are preferred. If the amount of the alkanoylating agent is less than the equivalent, alkanoylation does not occur sufficiently,
If the amount is too large, side reactions such as dehydration of the COOH group of A between molecules occur, which is not preferable.

The alkanoylation and precondensation are carried out while contacting with an alkanoylating agent to remove the corresponding acid. After the reaction is carried out preferably for 1 to 20 hours, more preferably for 3 to 10 hours under reflux of acetic anhydride, the formed acetic acid and excess acetic anhydride are removed. Continue with 150
0.5 to 5 while removing acetic acid further at ~ 260 ° C.
The reaction is continued for a time to complete the precondensation of Formulas A and E.
Polycondensation can also be performed by directly adding an aromatic dicarboxylic acid compound to the precondensation mixture. Alternatively, it is also possible to take out a predetermined amount once after cooling, and to carry out polycondensation with an aromatic dicarboxylic acid. 200-35 for polycondensation
The reaction is carried out at 0 ° C., preferably at 230 to 330 ° C., and the temperature is raised stepwise over 1 to 10 hours to remove generated acid, and the pressure is reduced (about 0.5 torr) to complete the reaction. The copolymerized polyester produced in the present invention has the above formula A, B,
It is composed of repeating units derived from C, D and E.

The aromatic copolyester of the present invention (I) /
The molar ratio of [(I) + (II)] is 1/100 to 85 /
100, preferably 1/100 to 78/100, particularly preferably 1/100 to 70/100. If the molar ratio exceeds 85/100, the melting temperature of the aromatic copolyester becomes high, and molding processing is difficult.

The molar ratio of (II) / (III) is 1-1.
When the molar ratio is less than 1, the polycondensation reaction rate is low, and a copolyester having a high degree of polymerization cannot be obtained.
In the case of 1.1 or more, a polymer having a high degree of polymerization can be obtained. This is not preferable because it easily occurs. The proportion of (B + C) in the aromatic dicarboxylic acid compound (II) is at least 5 mol%,
It is preferably at least 8 mol%. If the amount is less than 5 mol%, the melting temperature of the aromatic copolyester becomes high similarly to the above, and molding is difficult.

In addition to the above formulas A, B, C, D and E,
Formulas A, B, C, D and E may be substituted by small amounts of monomers capable of forming other ester bonds. Specific examples of other monomers capable of forming an ester bond include isophthalic acid, naphthalene-1,5-dicarboxylic acid, diphenylether-4,4′-dicarboxylic acid,
Dicarboxylic acid compounds such as diphenylsulfone-4,4'-dicarboxylic acid, diphenylketone-4,4'-dicarboxylic acid, 2,2'-diphenylpropane-4,4'-dicarboxylic acid, resorcinol, 2,5-dicarboxylic acid -T-butylhydroquinone, 2,3,5-trimethylhydroquinone, 1,5-dihydroxynaphthalene, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ) Dihydroxy compounds such as sulfone and bis (4-hydroxyphenyl) ether, m-hydroxybenzoic acid, 4-hydroxy-4′-carboxydiphenyl,
Oxycarboxy compounds such as -hydroxy-4-naphthoic acid can be mentioned. Of these monomers,
The substitution ratio with respect to (A + B + C + D + E) is set at 10 to make the melting point of the aromatic copolyester relatively low.
It is preferably at most mol%.

A feature of the present invention is that, in the production of the above-mentioned copolymerized polyester, after the alkanoylation of the formulas A and E and the catalytic reaction (precondensation), the dicarboxylic acid compound as the remaining comonomer component is added, and the polymerization is carried out. (Polycondensation reaction). The purpose of the precondensation is to suppress the formation of the homocondensate of formula A.

The precondensation and polycondensation reactions can be carried out in the presence or absence of a catalyst. Specific examples of the catalyst include stannous acetate, ferrous acetate, sodium acetate,
Examples include, but are not limited to, metals and metal compounds such as antimony trioxide, magnesium, iron (III) acetylacetone, and titanium tetrabutoxide. The amount of addition is 0.1 to the weight of the produced polymer.
001 to 0.5%. The timing of addition may be at the start of the precondensation reaction or at the start of the polycondensation.

Precondensation and polycondensation reactions can be carried out in the presence of a stabilizer for the purpose of preventing coloration due to thermal deterioration during polymerization and improving the thermal stability of the produced polymer. Specific examples of the stabilizer include, but are not limited to, phosphorus compounds such as phosphoric acid, phosphorous acid, sodium hypophosphite, triphenyl phosphate, and triphenyl phosphite. . The amount added is based on the weight of the polymer produced.
0.001 to 1%. The timing of addition may be at the start of the precondensation reaction or at the start of the polycondensation.

The aromatic copolyester produced according to the present invention is prepared at 60 ° C. in pentafluorophenol
At a concentration of 0.2 g / dl, logarithmic viscosity (η _inh ) 1.0
It has the above. The wholly aromatic copolyester produced according to the present invention exhibits optical anisotropy (liquid crystallinity) in a molten state when observed under a polarizing microscope. Further, by adopting this production method, a wholly aromatic copolyester having significantly reduced homoblocks of paraoxybenzoyl units, improved homogeneity and excellent heat resistance can be obtained.

The wholly aromatic copolyester produced according to the present invention forms a molten state at a relatively low temperature, for example, at a temperature of 400 ° C. or less, and can be formed into bulk molded articles and films by various commonly known molding methods. , Fibers and the like. Further, since it is dissolved in an organic polar solvent such as pentafluorophenol and p-chlorophenol, it is possible to obtain a molded article by a solution processing method. These molded articles can be widely used for electric, electronic, automotive materials and the like. As a remarkable property, since it has liquid crystallinity in a molten state, a molded article having a high degree of molecular orientation can be obtained, and thus a polymer material having excellent mechanical strength can be produced.

[0020]

Embodiments of the present invention will be described below. (Measurement method) Each physical property value shown in the examples of the present invention was measured by the following method. (1) Optical anisotropy: The sample was placed on a polarizing microscope, and the temperature was raised at a rate of 10 ° C./min under a nitrogen stream using a TH600 RMS type heating device manufactured by Linkham Inc., and observed visually. (2) Thermal decomposition onset temperature; SSC / Seiko Denshi Kogyo
Using a 5200 TGA instrument, the sample was placed in nitrogen at
And the change in weight over time was observed. (3) Melting point: SSC / 5200 manufactured by Seiko Denshi Kogyo KK
The sample was heated in nitrogen at a rate of 20 ° C./min using a DSC apparatus, and an endothermic peak was observed.

(4) Logarithmic viscosity: A sample was dissolved in pentafluorophenol at a concentration of 0.2 g / dl at 60 ° C. and measured using an Ubbelohde viscometer. η
_inh was calculated according to the following equation. _{η inh = In (t / t} o) / c However, _{t o} the dropping time of pentafluorophenol, t is the drop time of the sample solution, c is the concentration of the sample. (5) Melt viscosity Rheometrics dynamic spectrometer R
It was measured on a cone plate using DS (II). The polymer viscosity at 300 ° C. under a frequency of 1.0 Hz (6.28 RAD / SEC) and a nitrogen atmosphere was obtained.

Example 1 (PA / QA / TPA / HQ _u
/ PHBA = 20/16/24/60/40 (molar ratio)
Example) A stirrer, a nitrogen inlet tube, and a cooling tube were attached to a glass separable three-necked flask. This container, hydroquinone _{(HQ u) 33.69g (306mmol)} , p
-Hydroxybenzoic acid (PHBA) 27.62 g (20
0 mmol) and 87.04 g (853 mmol) of acetic anhydride.
1, 105% of equivalent). Stirring was continued for 4 hours in an oil bath maintained at 145 ° C. while introducing nitrogen. Next, the reaction solution was cooled to 100 ° C., and the generated acetic acid and excess acetic anhydride were distilled off under reduced pressure. The obtained reaction product was 92.85 g.

Using an upper part of a glass separable three-necked flask in a 100 ml SUS316 container,
1/5, that is, 18.57 g of the reaction product was charged into a vessel equipped with a nitrogen inlet tube and Claisen. After degassing with a vacuum pump and repeating nitrogen replacement three times, the mixture was heated at 240 ° C. for 30 minutes in a metal bath in which tin was dissolved, then heated to 250 ° C., the reaction was continued for 1 hour, and precondensation was performed. Completed. During this time, acetic acid produced was distilled off while flowing nitrogen. During this time, the reaction solution was colorless and transparent.
After the completion of the reaction, the pressure in the reaction vessel was reduced to 100 ° C. or less, thereby collecting 1.70 g of acetic acid. The reaction rate in the precondensation was estimated to be 96% from the amount of acetic acid formed.

To this precondensed mixture was added 3,3'-dimethylbiphenyl-4,4'-dicarboxylic acid (PA) 5.4.
1 g (20 mmol), 4.32 g of 3,4′-dimethylbiphenyl-4,3′-dicarboxylic acid (QA) (16 m
mol), 3.99 g of terephthalic acid (TPA) (24 m
mol) and 30 mg of triphenyl phosphite. After degassing with a vacuum pump and repeating nitrogen substitution three times, the mixture was heated in a tin solution at 240 ° C. for 30 minutes. The temperature was raised to 300 ° C. over 2.5 hours, kept at 300 ° C. for 1.5 hours, and the acetic acid generated was distilled off together with flowing nitrogen. While maintaining the temperature at 300 ° C., the degree of pressure reduction was gradually increased. Decompression degree is 0.
After reaching 1 torr or less, the reaction was continued for another 1 hour. After completion of the polycondensation reaction, the pressure was returned to normal temperature and normal pressure while introducing nitrogen. The obtained polymer was pulverized and taken out of the container. The fluidity of the obtained polymer was good. Table 1 shows the yield of the polymer, the temperature showing the optical anisotropy, the melting point, the thermal decomposition onset temperature, the logarithmic viscosity and the melt viscosity.

Example 2 (PA / QA / TPA / HQ _u /
PHBA = 15/15/30/60/40 (molar ratio)
Example) 4.05 g (15 mmol) of PA and 4.05 g of QA (1
5 mmol) and 4.98 g (30 mmol) of TPA were used in the same manner as in Example 1. The fluidity of the obtained polymer was good. Table 1 shows the yield of the polymer, the temperature showing the optical anisotropy, the melting point, the thermal decomposition onset temperature, the logarithmic viscosity and the melt viscosity.

[0026] Example 3 (PA / QA / TPA / HQ u
/ PHBA = 20/16/24/60/40 (molar ratio)
Example) In place of triphenyl phosphite, 32 mg of triphenyl phosphate was used, and the reaction time at 0.1 torr or less was 4
Except for 5 minutes, the same procedure as in Example 1 was performed. The fluidity of the obtained polymer was good. Polymer yield,
Table 1 shows the temperature, melting point, thermal decomposition onset temperature, logarithmic viscosity and melt viscosity showing the optical anisotropy.

[0027] Comparative Example stirrer, nitrogen inlet tube, a glass separable three-necked flask fitted with a _condenser, HQ u 10.1g (91.
8 mmol), PHBA 8.29 g (60 mmol),
8.11 g (30 mmol) of PA and 6.49 g of QA (2
4 mmol), 5.99 g (36 mmol) of TPA and 26.11 g of acetic anhydride (256 mmol, equivalent of 105
%). Stirring was continued for 4 hours in an oil bath maintained at 145 ° C. while introducing nitrogen. Next, the reaction solution was heated to 100 ° C.
The resulting acetic acid and excess acetic anhydride were distilled off under reduced pressure. The obtained product weighed 50.2 g. During the reaction, the system was heterogeneous as a white slurry. After taking out and pulverizing and mixing the product, 3
3.5 g (two-thirds of the charged amount) and 30 mg of triphenyl phosphite were charged in the same SUS316 reaction vessel as in Example 1. Thereafter, the same operation as in the polycondensation reaction of Example 1 was repeated. The fluidity of the obtained polymer was significantly inferior to the examples. In addition, under the observation with a polarizing microscope, the polymer exhibited optical anisotropy and was confirmed to have liquid crystallinity. However, insoluble components were mixed in the melt, and the polymer was not a uniform polymer. In addition, the melt viscosity was higher than in the examples, and the thermal decomposition onset temperature was lower than in the examples. Table 1 shows the yield of the polymer, the temperature showing the optical anisotropy, the melting point, the thermal decomposition onset temperature, the logarithmic viscosity and the melt viscosity.

[Table 1]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08G 63/00-63/91

Claims (1)

(57) [Claims] An alkanoylation and precondensation of an aromatic oxycarboxylic acid compound (I) represented by the following formula A and an aromatic dihydroxy compound (III) represented by the following formula E are contacted with an alkanoylating agent. And then one more
After the reaction at 50 to 260 ° C., the precondensate is converted to an aromatic dicarboxylic acid compound represented by the following formulas B, C, and D (I
I) and adding The polycondensation at a temperature in the range of 200 to 350 ° C., and the molar ratio of each compound to be subjected to the polycondensation reaction is defined as (I) /
[(I) + (II)] = 1/100 to 85/100,
(II) / (III) = 1 to 1.1, and the proportion of the compound (B + C) in the aromatic dicarboxylic acid compound (II) is at least 5 mol%, Manufacturing method. (In the above formula, R is a hydrogen atom,
It represents an alkyl group or an aryl group having 1 to 8 carbon atoms, or a halogen atom. )