JPH06206989A - Production of aromatic polyester - Google Patents

Abstract

PURPOSE:To produce an amorphous wholly aromatic polyester excellent in transparency by a melt polymerization method. CONSTITUTION:The method for producing the aromatic polyester by thermally melt-polycondensing (A) isophthalic acid and/or its ester forming derivative with (B) hydroquinone and/or its ester forming derivative and (C) 2,2-bis(4- hydroxyphenyl)propane and/or its ester-forming derivative in the presence of a catalyst is characterized in that the molar ratio of the component B/the component A is 50/50 to 80/20; the total amount of the components B and C is 95-120mol.% based on the component A; the polymerization temperature is 320-400 deg.C; an inert gas is blown into the reaction vessel at a flow rate of 1-200vol.%/min based on the total amount of the components A, B and C at the starting time of the reaction.

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, and more specifically, it is an amorphous product which gives a molded article having excellent transparency, heat resistance, mechanical properties and solvent resistance by melt molding. The present invention relates to a method for producing a hydrophilic aromatic polyester.

[0002]

2. Description of the Related Art Aromatic polyesters can be obtained with various characteristics such as an amorphous polymer, a crystalline polymer or a liquid crystalline polymer depending on the combination or composition of its constituent components. Among these, amorphous polymers are excellent in dimensional stability, transparency, mechanical properties, and heat resistance, and are considered 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. Development is being made by taking advantage of this. Applications of this polymer include automobile parts such as fog lamps, pharmaceutical parts such as eye drop containers, food containers and electronic parts. Further, this polymer has insufficient solvent resistance like ordinary amorphous polymers, is easily dissolved or swelled in various organic solvents, and its use is limited.

For the purpose of improving the solvent resistance, it has been proposed to use a part of hydroquinone as a diol component (Japanese Patent Laid-Open No. 52-7899). 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, as its production method, the hydroquinone component is extremely susceptible to oxidation, the solubility of the polymer is insufficient, and the like. Therefore, the solution polymerization method or the interface used as a production method of bisphenol A alone is used. The polymerization method cannot be adopted.

Therefore, according to the above-mentioned Japanese Patent Application Laid-Open No. 52-7899, production by a melt polymerization method is attempted as a production method of a polymer having a hydroquinone component introduced therein.
However, this method, as described in that example,
The target aromatic polyester is produced by solidifying or crystallizing the polymer in the melt polymerization process and subsequently solid-phase polymerizing the polymer.
This is because at a relatively low melt polymerization temperature of about 320 ° C. or less, it is difficult to obtain a high polymerization degree polymer having a high melt viscosity and capable of expressing sufficient toughness, and the polymer obtained by the hydroquinone component is crystallized. It is thought that this is because it is a characteristic that can be obtained. However, the method using such a solid-phase polymerization method has the drawbacks that the manufacturing process is complicated, the productivity is poor, and the cost is high.

The amorphous arylate produced by this method has solvent resistance, dimensional stability, mechanical properties, heat resistance,
It is excellent in transparency, and in particular, solvent resistance is improved, but transparency and hue are insufficient, and improvement thereof is desired.

[0006]

Therefore, in the present invention, solid phase polymerization is used in combination with an amorphous aromatic polyester having excellent mechanical properties, solvent resistance and stress crack resistance, and particularly excellent transparency and hue. The present invention is intended to provide a method for industrially inexpensively producing by a melt polymerization method.

[0007]

The present invention provides (A) isophthalic acid and / or its ester-forming derivative, (B)
Component (B) when heat-melt polymerizing hydroquinone and / or its ester-forming derivative and (C) 2,2-bis (4-hydroxyphenyl) propane and / or its ester-forming derivative in the presence of a catalyst. And the molar ratio (B / C) of the component (C) is 50/50 to 80/20,
The total amount of the component (B) and the component (C) is 95 to 120 mol% with respect to the component (A), the polymerization temperature is 320 to 400 ° C., and an inert gas is added to the reaction solution at the start of the reaction ( 1 to 200 with respect to the total amount of A), (B) and (C)
Reduced viscosity (in phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40), characterized in that it is blown at a flow rate of volume% / min, concentration 1.2 g / dl,
35 ° C.) is a method for producing an amorphous wholly aromatic polyester having a temperature of 0.3 to 1.0.

The present invention comprises isophthalic acid and / or its ester-forming derivative as component (A). Examples of the ester-forming derivative include alkyl ester, aryl ester, and acid chloride. As the component (A), isophthalic acid diaryl ester is preferable, and diphenyl isophthalate is particularly preferable.

Next, in the present invention, hydroquinone and / or its ester-forming derivative is the component (B), and bisphenol A and / or its ester-forming derivative is the component (C). Examples of the ester-forming derivative in this case include a lower fatty acid carboxylic acid ester, and an acetic acid ester is particularly preferable. In the present invention, hydroquinone can be preferably used as the component (B) and bisphenol A can be preferably used as the component (C).

The molar ratio (B / C) of the components (B) and (C) is 50/50 to 80/20. When the mole fraction of the component (B) is less than 50%, the solvent resistance and body stress cracking properties aimed at by the present invention become insufficient,
If it is more than 80 mol%, the resulting polymer tends to be crystalline, resulting in insufficient transparency. Ingredient (B)
The molar ratio (B / C) of the component (C) to the component (C) is preferably 55/4.
5 to 75/25, particularly preferably 60/40 to 70/3
It is 0. Further, in the method for producing a wholly aromatic polyester of the present invention, the total amount of the component (B) and the component (C) is in the range of 95 to 120 mol% with respect to the component (A), and this is subjected to polycondensation by heating. . The total amount of the component (B) and the component (C) is preferably 97 to 115 mol%, and 99 to 11
The range of 2 mol% is particularly preferable.

In the present invention, the above-mentioned components are heated and melt-polycondensed in the presence of a catalyst. As the catalyst used here, conventionally known ones used in the production of polyester can be used. Examples thereof include antimony compounds such as antimony trioxide, tin compounds such as stannous acetate, titanium compounds such as titanium tetrabutoxide, and germanium oxide. And other germanium compounds. The amount of the catalyst used is not particularly limited, but is 0.000 relative to the above component (A).
The amount is preferably in the range of 1 to 0.1 mol%.

The polymerization temperature during the heat polycondensation is 320 to 4
The temperature is preferably 00 ° C. Here, the polymerization temperature means the temperature at the latter stage of polymerization or at the end thereof. If the polymerization temperature is lower than 320 ° C., the melt viscosity of the polymer becomes high, so that a polymer having a high degree of polymerization cannot be obtained, and if it is higher than 400 ° C., the polymer is likely to deteriorate, which is not preferable.

In the production method of the present invention, it is preferred that the polymerization temperature is relatively low at the beginning and gradually raised to the above polymerization temperature. The reaction temperature of the initial polymerization reaction at this time is preferably 150 to 280 ° C, more preferably 180 to 250 ° C. This polymerization reaction is carried out under normal pressure or under reduced pressure, but it is preferable to carry out normal pressure during the initial polymerization reaction and gradually reduce the pressure.

The present invention is characterized in that an inert gas such as nitrogen or argon is blown into the reaction solution. Even in the conventional manufacturing method by melt polymerization, after charging the raw materials into the reaction vessel, depressurization → inert gas leak or pressurization with inert gas → depressurize to create an inert gas atmosphere and then in an inert gas stream. Although it is a common method to carry out the reaction, this method cannot sufficiently remove dissolved O ₂ in the molten reaction solution. The blowing is started preferably at normal pressure, more preferably at the time of heating and melting each component.

The inert gas blown in is nitrogen, argon, carbon dioxide, etc., and the O ₂ concentration in this gas is 10 pp.
It is necessary to be a member of m. This is because if the amount exceeds 10 ppm, the transparency of the produced polymer is insufficient.
Preferably, the O ₂ concentration in the gas is 5 ppm or less. The amount of the inert gas blown into the solution (A) at the start of the reaction,
1 to 200% by volume / based on the total amount of (B) and (C)
Min, preferably 20 to 100% by volume / min. According to the present invention, the amount of dissolved O ₂ can be reduced by blowing an inert gas into the reaction solution, and as a result, the coloring of the produced polymer due to oxidation can be significantly reduced. The polycondensation reaction time is not particularly limited, but is about 1 to 10 hours.

The aromatic polyester of the present invention obtained by the above-mentioned production method is used in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40) at a concentration of 1.2 g / dl at 35 ° C. The reduced viscosity measured by
It is 3 to 1.0. When the reduced viscosity is less than 0.3, the heat resistance and toughness of the polymer obtained are insufficient, and when it is more than 1.0, the fluidity at the time of melt molding is unfavorable. The reduced viscosity is preferably 0.4 to 0.8.

In a preferred embodiment of the present invention, diphenyl isophthalate is used as the component (A), hydroquinone is used as the component (B), and bisphenol A is used as the component (C). The amount of gas is adjusted by blowing an inert gas and gradually increasing the temperature. Next, the pressure of the reaction system is reduced from normal pressure to reduced pressure. At this time, it is preferable to stop the blowing of an inert gas and proceed with polycondensation. Further, since the aromatic polyester obtained by the present invention has a relatively high melt viscosity, it is also preferable to carry out the polymerization in combination with an extruder type reaction device in order to obtain a high degree of polymerization.

The aromatic polyester of the present invention obtained by the above-mentioned production method is an amorphous polymer, and a transparent molded article can be obtained by a melt molding method such as injection molding. Further, the fact that the polymer of the present invention is amorphous can be confirmed, for example, by its melting point not being observed by DSC. Further, the transparency of the polymer of the present invention can be confirmed by measuring the visible-ultraviolet absorption spectrum.

During the production of the aromatic polyester of the present invention, various stabilizers such as an oxidation stabilizer and an anti-coloring agent, and various additives such as a colorant, a pigment and a lubricant may be added if necessary.

[0020]

According to the production method of the present invention, by blowing a high-purity inert gas into the reaction solution, the transparency and the hue, which have hitherto been the drawbacks of the aromatic polyester produced by the melt polymerization method, can be obtained. It can be greatly improved. Furthermore, the aromatic polyester of the present invention has excellent heat resistance and toughness, and also has good solvent resistance and stress crack resistance, which are the drawbacks of amorphous polymers.
Combined with the inexpensive melt polymerization process, its industrial significance is extremely large.

[0021]

EXAMPLES The present invention will be described in detail below with reference to examples. In the examples, “parts” means “parts by weight”. The reduced 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 heat resistance of the polymer was measured by DSC at a temperature rising rate of 10 ° C./min. The transparency of the polymer was quantified by measuring the visible-ultraviolet absorption spectrum in tetrachloroethane at a concentration of 10 g / liter and a cell length of 1 cm.

[0022]

Example 1 318 parts diphenyl isophthalate (A), 256 parts hydroquinone (B), 109 parts bisphenol A (C), (where A / (B + C) =
1 / 1.08, B / C = 70/30), 0.09 parts of antimony trioxide (catalyst) and 0.33 parts of triphenyl phosphate (stabilizer), equipped with a stirrer and nitrogen blowing port. It is placed in a reaction vessel having a vacuum distillation system, the inside of the vessel is replaced with nitrogen, and then nitrogen (O
₍₂ concentration 7 ppm) was directly blown into the reaction solution at a flow rate of 150% by volume / min with respect to the total amount of the solutions (A), (B) and (C) at the initial stage of the reaction, and after holding at 240 ° C. for 30 minutes, 1 The temperature was raised to 340 ° C. over 5 hours.

Then, blowing of nitrogen was stopped, the pressure was gradually reduced at the same temperature, and after 30 minutes, the pressure was adjusted to about 1 mmHg. During this time, phenol was distilled off. Polymerization was performed for about 60 minutes under the same conditions to obtain a polymer. The polymer obtained had a reduced viscosity of 0.64, a glass transition temperature of 176 ° C., a light yellow transparent color, and an absorbance value at 400 nm of 0.015, indicating good transparency.

[0024]

Example 2 318 parts diphenyl isophthalate (A), 240 parts hydroquinone (B), 110 parts bisphenol A (C), (where A / (B + C) =
1 / 1.10, B / C = 68.5 / 31.5), 0.0
9 parts of antimony trioxide (catalyst) and 0.33 part of triphenyl phosphate (stabilizer) were placed in a reaction kettle having a vacuum distillation system equipped with a stirrer and a nitrogen inlet, and the inside of the kettle was depressurized → nitrogen. After substituting nitrogen by a gas leak method, nitrogen (O ₂ concentration 5 ppm) was directly added to the reaction solution at a normal pressure of 8 with respect to the total amount of the solutions (A), (B) and (C) at the initial stage of the reaction.
30% at 240 ° C while blowing at a flow rate of 0% by volume / minute
After holding for 1 minute, the temperature was raised to 340 ° C. over 1.5 hours.

Next, the blowing of nitrogen was stopped, the pressure was gradually reduced at the same temperature, and after 30 minutes, the pressure was adjusted to about 1 mmHg. During this period, phenol was generated and distilled off. Polymerization was performed for about 60 minutes under the same conditions to obtain a polymer. The polymer obtained had a reduced viscosity of 0.66, a glass transition point of 176 ° C., a yellow transparent color, and an absorbance value at 400 nm of 0.014, indicating good transparency.

Next, this polymer was injection molded using an injection molding machine (N50B type, manufactured by Meiki Seisakusho) under the conditions of a cylinder temperature of 360 ° C., a mold temperature of 90 ° C. and a molding cycle of about 60 seconds. Table 1 shows the physical properties of the obtained molded product. Although Table 1 also shows the aromatic polyester of Comparative Example 2 for comparison, it can be seen that the production method of the present invention has excellent transparency.

[0027]

Comparative Example 1 318 parts diphenyl isophthalate (A), 256 parts hydroquinone (B), 109 parts bisphenol A (C), (where A / (B + C) =
(1 / 1.08, B / C = 70/30), 0.09 parts of antimony trioxide (catalyst) and 0.33 parts of triphenyl phosphate (stabilizer) in a vacuum distillation system equipped with a stirrer The reaction vessel was charged with nitrogen, and the inside of the reaction vessel was replaced with nitrogen. After maintaining at 240 ° C. for 30 minutes in a nitrogen stream under normal pressure, the temperature was raised to 340 ° C. over 1.5 hours.

Then, the pressure is gradually reduced at the same temperature to 30
After 1 minute, the pressure was set to about 1 mmHg. During this period, phenol was generated and distilled off. Polymerization was performed under the same conditions for about 60 minutes to obtain a polymer. The polymer obtained had a reduced viscosity of 0.63, a glass transition point of 172 ° C., a light brown transparent color, and a thickness of 400 n.
The absorbance value of m was 0.047.

[0029]

Comparative Example 2 318 parts of diphenyl isophthalate (A), 240 parts of hydroquinone (B), 110 parts of bisphenol A (C), (where A / (B + C) =
1 / 1.10, B / C = 68.5 / 31.5), 0.0
9 parts of antimony trioxide (catalyst) and 0.33 part of triphenyl phosphate (stabilizer) were placed in a reaction kettle having a vacuum distillation system equipped with a stirrer, and the inside of the kettle was decompressed → by nitrogen gas leak method. After replacing with nitrogen, under normal pressure, in a nitrogen stream 24
After holding at 0 ° C for 30 minutes, the temperature was raised to 340 ° C over 1.5 hours.

Then, the pressure is gradually reduced at the same temperature, and the pressure is reduced to 30
After 1 minute, the pressure was set to about 1 mmHg. During this period, phenol was generated and distilled off. Polymerization was performed under the same conditions for about 90 minutes to obtain a polymer. The polymer obtained had a reduced viscosity of 0.79, a glass transition point of 174 ° C., a light brown transparent color, and a thickness of 400 n.
The absorbance value of m was 0.027.

Next, this polymer was injection molded using an injection molding machine (N50B type, manufactured by Meiki Seisakusho) under the conditions of a cylinder temperature of 360 ° C., a mold temperature of 90 ° C. and a molding cycle of about 60 seconds. Table 1 shows the physical properties of the obtained molded product.

[0032]

[Table 1]

Claims (1)

[Claims] 1. (A) Isophthalic acid and / or its ester-forming derivative, (B) Hydroquinone and / or its ester-forming derivative and (C) 2,2-bis (4-hydroxyphenyl) propane and / or When the ester-forming derivative is heated and melt-polymerized in the presence of a catalyst, the molar ratio (B / C) of the component (B) and the component (C) is 50/50 to 80/20, the component (B) and the component (B). The total amount of (C) is 95 to 120 mol% with respect to the component (A), the polymerization temperature is 320 to 400 ° C., and an inert gas is added to the reaction solution at the start of the reaction (A) and (B). And a reduced viscosity (phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40), which is blown at a flow rate of 1 to 200% by volume / min with respect to the total amount of (C). Medium, concentration 1.2g / dl, 3 5 ° C.) 0.3 to 1.0, a method for producing an amorphous wholly aromatic polyester.