JPS5931527B2 - Polyester manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing polyester.

For more details, please refer to Polymer with excellent heat resistance, transparency, and chemical resistance.
. This invention relates to an improved method for producing esters. Polyethylene terephthalate is widely used industrially due to its excellent mechanical properties and chemical resistance, but its relatively low heat distortion temperature (heat resistance) and fast crystallization rate make it difficult to maintain dimensional stability and transparency. It has the disadvantage of lacking in

Conventionally, attempts have been made to overcome these drawbacks by subjecting aromatic dicarboxylic acid derivatives and aromatic dihydroxy compounds to a polycondensation reaction.

For example, (a) a method in which an aromatic dicarboxylic acid chloride and an aromatic dihydroxy compound are reacted in a solution, (b) a method in which a diaryl ester of an aromatic dicarboxylic acid and an aromatic dihydroxy compound are melt-polymerized, (c) aromatic A method of reacting a group dicarboxylic acid, an aromatic dihydroxy compound, and a diaryl carbonate is known.
However, since method (a) uses a reaction solvent, it requires steps such as solvent removal and purification, and there are many manufacturing steps, which poses problems in productivity. There are problems as an industrial method because expensive raw materials such as diaryl esters of aromatic dicarboxylic acids and diary carbonates are used.

In addition, as a method for producing polyester without such drawbacks,
Difunctional carboxylic acids (2
) and an aromatic monohydroxy compound (B) in an amount of 2.1 to 10 moles relative to the bifunctional carboxylic acid at 230 to 350°C.
, under an absolute pressure of 1 to 15 9/c-nl until the reaction rate of the carboxyl group of the (supporting) component reaches 80% or more, and then 1 to 1.3 to the difunctional carboxylic acid.
A method for producing polyester has been proposed, which is characterized by adding and reacting a dihydroxy compound (c) mainly consisting of an aromatic dihydroxy compound in twice the molar amount (Japanese Patent Laid-Open No. 1983-1992).
(See Publication No. 41094). This method uses aromatic dicarboxylic acid as a starting material and has the advantage of being able to easily and inexpensively produce polyester with excellent heat resistance, dimensional stability, transparency, and chemical resistance. It has drawbacks such as low workability such as the need to control the reaction pressure during the reaction, and high coloring of the polyester obtained.

As a result of intensive studies to improve this drawback, the inventor of the present invention found that
The inventors discovered that a polyester with excellent color tone could be obtained by using a specific medium, leading to the present invention.

That is, the present invention provides bifunctional carboxylic acids (4) mainly consisting of aromatic dicarboxylic acids and components (4) with a concentration of 2.1 to 1
0 moles of the aromatic monohydroxy compound (self) in the presence of a medium at an absolute pressure of 1 to 25 kg/CTi, 230
React at a temperature of ~350°C until the reaction rate of the carboxyl group of component (A) reaches 80% or more, then (4)
When the aromatic dihydroxy compound (c) is added in an amount of 1 to 1.3 times the mole of the components to cause a reaction, the medium has a boiling point of 105 to 175°C under normal pressure, does not substantially dissolve water, and does not react with the aromatic dihydroxy compound (c). This is a method for producing polyester characterized by using an organic compound that is inert at temperature.

In the present invention, aromatic dicarboxylic acids are mainly used as the difunctional carboxylic acids used as the prison component.

Examples of such aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 4-methylterephthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, and diphenylated dicarboxylic acid. Examples include carboxylic acid and ethanedicarboxylic acid. These can be used alone or in combination of two or more. Among these, terephthalic acid and isophthalic acid are particularly preferably used. In addition to the above-mentioned aromatic dicarboxylic acid, as component (4), a small proportion (usually 40 mol% or less of the total acid components, preferably 20 mol % or less) of other difunctional carboxylic acids, such as succinic acid, adipine, etc. Aliphatic dicarboxylic acids such as sebacic acid; alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, etc.; ε-
Oxycarboxylic acids such as oxycaproic acid (ε-caprolactone), hydroxybenzoic acid, etc. may also be used. The aromatic monohydroxy compound used as the (auto) component in the present invention is a compound in which one hydroxy group is directly bonded to the aromatic ring, and examples thereof include phenol, talesol, naphthol, and the like.

Among these, phenol is particularly preferably used. The proportion of the aromatic monohydroxy compound used is 2.1 to 10 times the mole of the difunctional carboxylic acid.

If this ratio is less than 2.1 moles, the reaction rate will be slow, and if it exceeds 10 moles, no significant increase in effect can be expected. Furthermore, the dihydroxy compounds used as component (c) in the present invention are mainly aromatic dihydroxy compounds.

The aromatic dihydroxy compound is a compound in which two hydroxy groups are directly bonded to an aromatic ring, such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 1,1-bis(4 -hydroxyphenyl)cyclohexane (bisphenol Z), 1,1-bis(4-
hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)cyclohexylmethane, 3,3-bis(4-hydroxy) Examples include phenino(ha)pentane, bis(4-hydroxyphenyl)ether, and 1,4-dihydroxybenzene.
Although these can be used alone, two or more types can also be used in combination. Among these, especially bisphenol A
1-bisphenol Z A mixture of these and 1,4-dihydroxybenzene is preferably used. In addition to the above-mentioned aromatic dihydroxy compound, component (c) may include, for example, (
Other dihydroxy compounds may be used in a proportion of up to 50 mol% of component c). Such other dihydroxy compounds include, for example, aliphatic diols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, neopentylene glycol, hexamethylene glycol, etc.; cyclohexane dimethylol, tricyclodecane dimethylol, etc. Aliphatic diols such as bis(β-hydroxyethoxy)diphenyl sulfone, 4,4-bis(β-hydroxyethoxy)diphenyl ether, 2,2-bis(4-β-hydroxyethoxyphenino(ha)ethane, 2,2-bis(4-β-
Aliphatic diols having an aromatic ring in the molecule such as hydroxyethoxyphenyl)propane, 1,1-bis(4-β-hydroxyethoxyphthenyl)cyclohexane, P-bis(β-hydroxyethoxy)benzene, etc. I can give it to you. The other dihydroxy compound is usually used as it is, but if desired, it may be added as an ester of dicarboxylic acid or oxycarboxylic acid or a polymer thereof. The proportion of component (c) used is 1 to 1.3 times, preferably 1.02 to 1.2 times, by mole relative to the difunctional carboxylic acid. If this ratio is less than 1 mole, 1.
When the amount exceeds 3 moles, it is difficult to obtain the desired polyester with a high degree of polymerization. In the present invention, component (4) and (
A medium is present in the reaction of the component (self), and this medium is a compound that exists at least partially in a liquid state under the reaction conditions, and has a boiling point of 105 to 175 ° C. under normal pressure,
Any organic compound may be used as long as it does not substantially dissolve water and is inert at the reaction temperature, for example, a boiling point of 105
A hydrocarbon having a temperature of 175° C. to 175° C. and having no reactive unsaturated bonds is preferably used.

Preferred examples of such compounds include alkyl-substituted benzenes such as toluene, xylene, ethylbenzene, cumene, cymene, trimethylbenzene, and ethyltoluene. Among these, ethyl-2-lebenzene is particularly preferred. A medium with a boiling point of less than 105° C. cannot be used because the reaction pressure will be high and in some cases it will be difficult to separate it from the water produced, or it will be distilled off before the water. On the other hand, a medium with a boiling point exceeding 175° C. only acts as a diluent and cannot enhance the effects of the present invention. In the present invention, first, the prisoner component and component (9) are mixed at a temperature of 230 to 350°C and an absolute pressure of 1 to 25 k9/? React under pressure.

During this reaction, it is necessary in the present invention to coexist the medium as described above. The amount of this medium to be used varies depending on the reactor, so it cannot be determined unambiguously, but it is preferable to set the amount such that a portion of the medium always distills from the top of the distillation column of the reactor. Since this distilled medium, which is usually used in an amount of 0.01 to 10 times the weight of the aromatic dicarboxylic acid, easily separates into layers from water, it is a preferable method to reflux the medium after separation and reuse it. Also, the addition time is esterification rate 2
Preferably, it is before it reaches 0%. In the above reaction, the carboxyl group of the prisoner component is 80% or more, preferably 85%
Do this until the reaction occurs.

The preferred reaction temperature is 250-320C. Further, in order to carry out the reaction more effectively, water produced by the reaction is distilled off from the reaction system. The above-mentioned medium is effective in distilling off this water, and if no medium is used, it is necessary to adjust the way the distilled water comes out by adjusting the reaction pressure, etc., but according to the present invention, it is possible to remove the distilled water at a constant pressure. It became possible to carry out the reaction by refluxing the medium. The above prisoner component and (
It is preferable to use a catalyst in the reaction of the above component, and examples of the catalyst include titanium tetrabutoxide, titanium tetrabutoxide,
Examples include titanium compounds such as titanium oxalate and titanium oxide, tin compounds such as dibutyl toxide, and antimony compounds such as antimony trioxide.

The amount of catalyst used is usually 0.01 to 5 mol % based on the prisoner component. (4) The reaction between the component and the (self) component is as described above.
(4) The carboxyl group of the component is 80% or more, preferably 85? Do this until the reaction occurs.

If the reaction rate of carboxyl group is less than 80%,
Next, the reaction with component 0 (0) does not proceed sufficiently and it is not possible to obtain the desired polyester with a high degree of polymerization.After reacting component (4) and component (B), Then, the medium and excess component (B) are expelled and the next polycondensation reaction is carried out.The polycondensation reaction is carried out after adding the component (O) to the reaction product of the active component and the component.

The preferred temperature for the polycondensation reaction is 200 to 3500 C1, and the preferred pressure is 760 to 0.001 mm119. The reaction is usually carried out in a molten state, but if the resulting polymer has a high melting point, solid phase polymerization is also preferably employed. In the present invention, additives such as catalysts, stabilizers, and colorants that are commonly used in polyester production can be used without any problem.

According to the present invention, it has high heat resistance, dimensional stability, transparency,
A highly polymerized polyester with excellent chemical resistance and color tone can be easily and inexpensively produced using an aromatic dicarboxylic acid as a starting material.

Furthermore, the present invention has the advantage that the reaction operation is easy. The present invention will be explained in detail below with reference to Examples. Note that "part" in the examples means "part by weight", and the reduced specific viscosity (ηSp
/c) is phenol/tetrachloroethane-60/40
This is a value measured as C-1.2 at 35°C using a mixed solvent of (weight ratio). In addition, the carboxyl group value was determined by the Konics method (MacrQ.Molecular.Ch
em. , 26, 226, 1958), and the heat distortion temperature was measured by the method of ASTM D-648. 1st
The reaction rate of each step is determined by the following formula. [In the above formula MA, MB
are the molecular weights of component (4) and component (3), respectively, a mixture of two or more is the average molecular weight, and CV is the carboxyl group value of the reaction product after washing with water.

] Furthermore, the b value of the color tone was measured using a CM-20 model color correction manufactured by Color Machine Co., Ltd.

A large b value indicates strong yellowing. Example 1 Terephthalic acid 8 was added to a rectification column and an autoclave equipped with a stirrer.
3.0 parts, isophthalic acid 83.0 sounds - phenol 376
1 part, 50 parts of ethylbenzene, and 0.12 part of tin acetate were charged, and after purging with nitrogen, the pressure was returned to normal pressure and the autoclave was heated.

Water and ethylenebenzene as by-products were distilled out while keeping the internal temperature at 280°C, and the upper layer (ethylbenzene layer) in the distillate was refluxed to the upper part of the rectification column. After 280 minutes, the lower layer portion in the distillate was 31 parts.

During this time the pressure naturally changed from 10k9/Cd to 8k9/~. A portion of the obtained product was dried under reduced pressure at 12° C. overnight, washed with water, and after drying again, the carboxyl group value was measured and found to be 620 eq/1069 (reaction rate 89%). Next, this product was transferred to a reactor equipped with a stirrer, and after adding 239.4 parts of bisphenol A, 280 parts of bisphenol A was added thereto.
C. for 60 minutes, then the pressure in the system was gradually reduced, and after 30 minutes, the absolute pressure was reduced to about 0.5 mmII9, and the reaction was continued for an additional 150 minutes. The obtained polymer had a ηSp/CO. 83, and the polymer was injection molded at 290°C after drying.
The b value of the molded product with a thickness of mm was measured and found to be 11. Comparative Example 1 Terephthalic acid 8 was added to the rectification column and autotaleve with stirrer.
3.0 parts, isophthalic acid 83.0 parts, phenol 376
After replacing the reaction system with nitrogen, the reaction system was heated to 280°C while adjusting the nitrogen pressure so that the absolute pressure in the reaction system was 6.51<9/~. After 20 minutes, water was removed. Distillation has begun.

Furthermore, the reaction was allowed to proceed for 310 minutes while gradually lowering the absolute pressure to 5.0k9/CTi. During this time, about 31 parts of water was distilled off. A portion of the obtained product was taken, and after washing with water, the carboxyl group value was measured and found to be 628 eq/1069 (reaction rate 8
9%). Next, this product was transferred to a reactor equipped with a stirrer, 239.4 parts of bisphenol A was added thereto, and the temperature was maintained at 280°C under normal pressure for 60 minutes.Then, the pressure inside the system was gradually reduced and the absolute pressure was reduced to approximately 0.5 m19 after 30 minutes. , the reaction was continued for an additional 150 minutes.

Claims (1)

[Claims] 1 A difunctional carboxylic acid (A) mainly consisting of an aromatic dicarboxylic acid and an aromatic monohydroxy compound (B) in an amount of 2.1 to 10 times the mole of component (A) in the presence of a medium at an absolute pressure of 1
The reaction was carried out at a pressure of ~15 kg/cm^2 and a temperature of 230 to 350°C until the reaction rate of the carboxyl group of component (A) reached 80% or more, and then 1 to
When carrying out an addition reaction with 1.3 moles of a dihydroxy compound, mainly an aromatic dihydroxy compound, the medium has a boiling point of 105 to 175°C under normal pressure, does not substantially dissolve water, and is suitable for the reaction. A method for producing polyester, characterized by using an organic compound that is inert at temperature.