JP4582393B2 - Polyester production method - Google Patents

Description

  The present invention relates to a method for producing polyester with greatly improved productivity.

  Polyesters typified by polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), etc. are excellent in mechanical properties and chemical properties. Depending on the properties of each polyester, for example, Used in a wide range of fields such as textiles for clothing and industrial materials, films and sheets for packaging, magnetic tape, optics, bottles that are hollow molded products, casings for electrical and electronic components, and other engineering plastic molded products Has been. In particular, bottles made of saturated polyesters such as PET are excellent in mechanical strength, heat resistance, transparency and gas barrier properties, so that they are used as containers for filling beverages such as juices, carbonated drinks and soft drinks, and containers for eye drops and cosmetics. Widely used.

  For example, in the case of PET, a polyester having aromatic dicarboxylic acid and alkylene glycol as main components as a typical polyester is bis ((ester) by esterification reaction or transesterification reaction between terephthalic acid or dimethyl terephthalate and ethylene glycol. An oligomer mixture such as 2-hydroxyethyl) terephthalate is produced, and this is produced by liquid phase polycondensation using a catalyst at high temperature under vacuum. In these production methods, a so-called direct polymerization method using terephthalic acid is widely practiced because it is advantageous in terms of raw material costs.

In recent years, PET, which is the most representative polyester, has been faced with severe price competition for general-purpose products with the expansion of global production plants.
In the production of polyethylene terephthalate by this direct polymerization method, in order to suppress side reactions in the esterification reaction step and to carry out the production economically, the ratio of terephthalic acid and ethylene glycol used as raw materials for the esterification reaction (Diol / dicarboxylic acid; hereinafter referred to as “molar ratio”) is one of the important factors to control the characteristics of the low polymer that is an intermediate obtained by the esterification reaction by a method such as moderate preparation. .

For example, in the production of polyethylene terephthalate as described above, by controlling the progress of the esterification reaction by paying attention to the degree of polymerization of the reaction product and the composition of the terminal group, the latter polycondensation reaction can be further shortened, which is high overall. It is disclosed that productivity can be obtained (see Patent Document 1).
JP 2000-19176 A

  From the above situation, establishment of a manufacturing method that drastically reduces production costs that cannot be achieved by the conventional technology that further improves productivity and reduces equipment costs is strongly desired.

  The present invention has been made against the background of the problems of the prior art, and the object of the present invention relates to a method for producing polyester, and the production cost with improved productivity and reduced equipment costs is dramatically increased. An improved method for producing polyester is provided.

  In order to solve the above problems, the present invention has been completed as a result of intensive studies. That is, the present invention relates to a method for producing a polyester by polycondensation of a product obtained by an esterification reaction of a dicarboxylic acid and a glycol, in which the hydroxyl value of all the end groups of the reaction product at the outlet of the final esterification reactor is adjusted. An esterification product having a ratio of 45 to 70 mol% is obtained, and the ratio of the hydroxyl value to the total end groups of the reaction product is 55 to 78 in a transfer line for transferring the reaction product to the polycondensation reaction tank. This is a method for producing a polyester, characterized in that a glycol in an amount of mol% is added and then a polycondensation reaction is carried out.

  The method for producing the polyester of the present invention can provide a polymer having a high degree of polymerization in a shorter time than conventionally known methods. Moreover, it can respond with the more simplified installation compared with the conventionally well-known thing. Therefore, there is an advantage that the production cost of the polyester can be drastically reduced as compared with a conventionally known production method.

Hereinafter, the present invention will be described in detail.
The polyester referred to in the present invention refers to a polyester comprising a dicarboxylic acid and / or an ester-forming derivative thereof and a diol and / or an ester-forming derivative thereof.

  Dicarboxylic acids include succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1,3 -For cyclobutane dicarboxylic acid, 1,3-cyclopentane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 2,5-norbornane dicarboxylic acid, dimer acid, etc. Saturated aliphatic dicarboxylic acids exemplified, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid, etc., or ester-forming derivatives thereof, orthophthalic acid, isophthalic acid, terephthalic acid acid, -(Alkali metal) sulfoisophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid Acid, 4,4′-biphenyldicarboxylic acid, 4,4′-biphenylsulfone dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, pamoin Examples thereof include aromatic dicarboxylic acids exemplified by acids, anthracene dicarboxylic acids and the like, and ester-forming derivatives thereof.

  Of these dicarboxylic acids, terephthalic acid and naphthalenedicarboxylic acid, particularly 2,6-phthalenedicarboxylic acid, are preferred from the viewpoint of the physical properties of the resulting polyester, and other dicarboxylic acids are used as constituents if necessary.

In addition to these dicarboxylic acids, a polyvalent carboxylic acid may be used in combination if the amount is small. Examples of the polyvalent carboxylic acid include ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3, 4, 3 ′, 4′-biphenyltetracarboxylic acid, and these Examples thereof include ester-forming derivatives.

  As glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4 -Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethyl Aliphatic glycols exemplified by tylene glycol and polytetramethylene glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) ) Sulfone, bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2 , 5-naphthalenediol, aromatic glycols exemplified by ethylene glycol added to these glycols, and the like.

  Of these glycols, ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, and 1,4-cyclohexanedimethanol are preferred.

  In addition to these glycols, polyhydric alcohols may be used in combination in small amounts. Examples of the polyhydric alcohol include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol, and the like.

  Moreover, you may use together hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 4-hydroxycyclohexanecarboxylic acid, or these And ester-forming derivatives thereof.

  Moreover, combined use of cyclic ester is also permitted. Examples of the cyclic ester include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

  Examples of ester-forming derivatives of polyvalent carboxylic acids or hydroxycarboxylic acids include alkyl esters and hydroxylalkyl esters of these compounds.

  Examples of ester-forming derivatives of diols include esters of diols with lower aliphatic carboxylic acids such as acetic acid.

  As the polyester of the present invention, PET, PBT, polypropylene terephthalate, poly (1,4-cyclohexanedimethylene terephthalate), PEN, polybutylene naphthalate, polypropylene naphthalate and copolymers thereof are preferable. Among these, polyethylene terephthalate and This copolymer is particularly preferred. As a copolymer, what consists of 50 mol% or more of ethylene terephthalate units is preferable, and 70 mol% or more is more preferable. PET is particularly preferred.

In the method for producing a polyester of the present invention, in the method for producing a polyester by polycondensation of the product obtained by the esterification reaction of the above dicarboxylic acid and glycol, the reaction product at the outlet of the final esterification reaction vessel An esterification product having a hydroxyl value ratio (OHV ₁ %) to the total terminal groups of 45 to 70 mol% is obtained, and the reaction product is transferred to a transfer line for transferring the reaction product to a polycondensation reaction tank. It is necessary to add the glycol in such an amount that the ratio of hydroxyl value to the total terminal groups (OHV ₂ %) is 55 to 78 mol%, followed by the polycondensation reaction. OHV ₁ % and OHV ₂ % are more preferably set to 45 to 60 mol% and 55 to 76 mol%, respectively, and are 45 to 55 mol% and 55 to 74 embodiments. If the OHV ₁ % and OHV ₂ % are less than 45 and 55 mol%, respectively, the polycondensation reaction becomes unstable, such being undesirable. On the contrary, when OHV ₁ % and OHV ₂ % exceed 70 and 78 mol%, respectively, the polycondensation activity of the polycondensation catalyst decreases and the polycondensation productivity decreases, which is not preferable. Moreover, it is not preferable at the point of the productivity reduction of an esterification reaction process, the increase in equipment cost, and the side reaction by which glycols react and an ether bond is formed, etc. increase. For example, if the reaction product is produced in one esterification reaction tank, side reactions such as reaction between glycols increase, and the quality of the final product polyester decreases. When the number of esterification reaction tanks is increased in order to solve this problem, the number of facilities is increased, and the productivity of the esterification process is lowered to deteriorate the economic efficiency.

In the present invention, as described in claim 2, the esterification rate (Es%) of the reaction product at the outlet of the final esterification reactor is 80 to 96 mol% and the average degree of polymerization (Pn) is 3 or more. preferable. Es% is preferably 82 to 93 mol%, and Pn is preferably 4 or more. If Es% is less than 80 mol% or exceeds 96 mol%, it is not preferable because it leads to the same problem as in the case of OHV ₁ % or OHV ₂ %. On the other hand, when Pn is less than 3, the productivity of the next polycondensation step is lowered, which is not preferable.

  The composition of the final esterification reaction product is, for example, a composition very close to the low polymer expressed as Z1 which is an intermediate product of the esterification reaction disclosed in Patent Document 1 described above. Accordingly, this is a technique in which the reaction in the latter half of the technique disclosed in Patent Document 1 is omitted, and the ester productivity is greatly improved as compared to the known technique, and the esterification is performed. Equipment costs for the reaction process can be greatly reduced. Furthermore, in the present invention, the progress of the polycondensation reaction in the next step is also promoted as compared with the prior art, and the productivity in the polycondensation step is also improved. Since the technique itself disclosed in Patent Document 1 is a production method in which productivity is improved as compared with the conventional technique, the production method of the polyester of the present invention is a production method of polyester as compared with a conventionally known production method of polyester. Cost can be drastically reduced.

In the above method, the glycol added to the transfer line for transferring the esterification reaction product to the polycondensation reaction tank in order to satisfy OHV ₂ % has a primary hydroxyl group and has esterification reactivity. It will not be limited if it is taken in as a structural component of polyester. For example, the glycol component which comprises above-described polyester is mentioned. The glycol may be the same or different from the components used in the esterification reaction step. A method using a different glycol component as the glycol is useful as a method for producing a copolyester. The glycol may be added as a single product of glycol, or may be added in a form in which a functional agent such as a polycondensation catalyst, a stabilizer, or a pigment is dissolved or dispersed. In particular, the latter is recommended because it can lead to a reduction in the total amount of glycol used in the polyester production process. The method for adding the glycol is not limited and is arbitrary. For example, it may be introduced by adding pressure to the transfer line, or may be added to the in-line mixer by installing an in-line mixer in the transfer line. The latter method is preferable because mixing of the esterification reaction product and glycol is promoted. In particular, when the aforementioned functionalizing agent is added in a mixed form, mixing of the esterification reaction product and the functionalizing agent is promoted, so that the latter is recommended. In the former method, a static mixer may be installed in the transfer line after the place where the glycol is added to promote mixing and reaction with the reaction product. The glycol may be added in two or more places. Since the equipment cost of the addition method can be greatly reduced compared to the equipment cost of the esterification reaction tank, it can be said that this is an extremely useful method from the viewpoint of economy.

  The present invention can be applied to any of the batch-type polycondensation method and the continuous-type polycondensation method, but it is preferably adapted to the continuous polycondensation method which is advantageous in quality uniformity and economy. The number and size of reaction vessels in the esterification and polycondensation steps, production conditions for each step, and the like can be appropriately selected without limitation. However, it is preferable that the number of esterification reaction tanks is one as described in claim 3 from the viewpoint of taking advantage of the great feature of the present invention that the esterification rate of the reaction product at the outlet of the final esterification reaction tank is low. With this measure, the equipment cost can be greatly reduced, leading to a reduction in the production cost of polyester.

A method for producing PET by direct esterification is illustrated below.
A slurry containing 1.02 to 1.3 moles, preferably 1.03 to 1.2 moles of ethylene glycol per mole of terephthalic acid was prepared and this was continuously added to the esterification reaction step. To supply.

The esterification reaction is carried out using a one-stage apparatus consisting of one reaction tank under conditions where ethylene glycol is refluxed while removing water produced by the reaction from the system using a rectification column. The reaction temperature is 250 to 285 ° C., preferably 260 to 282 ° C., and the pressure is 0.2 to 3 kg / cm ² G, preferably 0.5 to ² kg / cm ² G. Subsequently, it is transferred to a polycondensation reaction tank to carry out polycondensation. The esterification reaction may be carried out using a multistage apparatus comprising two or more reaction vessels. The number of reaction tanks in the polycondensation step is not limited. Generally, a two-stage system of initial polycondensation and late polycondensation is taken. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 Torr, preferably 200 to 30 Torr. The temperature is 265 to 300 ° C., preferably 275 to 295 ° C., and the pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When carried out in three or more stages, the reaction conditions for the polycondensation reaction in the intermediate stage are intermediate conditions between the reaction conditions in the first stage and the reaction conditions in the final stage. The degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is preferably distributed smoothly. The polycondensation step is preferably applied to a one-stage apparatus which is carried out in one reaction tank for the same reason as the esterification reaction step.

In the present invention, the polycondensation catalyst is not limited and can be arbitrarily selected including conventionally known antimony compounds such as antimony trioxide, germanium compounds such as germanium dioxide, titanium compounds such as tetrabutyl titanate, etc., but it improves productivity. From the viewpoint of this, it is a preferred embodiment to select a polycondensation catalyst system having a strong activity for the esterification reaction to promote the esterification reaction. Furthermore, by using a polycondensation catalyst system having a strong activity for the esterification reaction, by making OHV ₂ % within the scope of the present invention, the activity of the polycondensation reaction can be greatly increased as compared with the case where it is higher than the scope of the present invention. This is preferable because it leads to the effect that the productivity of the polycondensation reaction is greatly improved and the characteristics of the present invention can be expressed more effectively. That is, when a polycondensation catalyst system having a strong activity for the esterification reaction is used, the polycondensation reaction step also has an effect of improving the productivity of the polycondensation reaction by adding a reaction of increasing the degree of polymerization due to the esterification reaction. Expressed. Examples of the polycondensation catalyst system having a strong activity for the esterification reaction include a system comprising a titanium compound, a tin compound, an aluminum compound and the like.

  The addition timing of the polycondensation catalyst is not limited, and may be any time before the esterification reaction starts, during the esterification reaction, or after the esterification reaction ends. The polycondensation catalyst may be used alone or in combination of two or more.

  In order to take advantage of the characteristics of the present invention, it is preferable to set the glycol mole relative to the dicarboxylic acid at the start of the esterification reaction to a relatively low value as described above, so that the viscosity of the mixture of dicarboxylic acid and glycol is relatively low. Get higher. For this reason, in order to prevent clogging of the mixture in the liquid supply pipe or pump, or to improve fluidity, a method of adding 10% by weight or less of water to the total amount of dicarboxylic acid and glycol is taken. Also good.

A major object of the present invention is to provide a method for producing polyester with greatly improved productivity, and it is important to apply the above-mentioned method, but at the same time consider the quality of the polyester obtained, especially the color tone. It is important to. That is, it is effective to increase the temperature of the manufacturing process in order to improve productivity. When the temperature of the production process is increased, the color tone of the obtained polyester deteriorates. In particular, the yellowness deteriorates. Therefore, the obtained polyester preferably has a color tone b value, which is a measure of yellowness, of 5 or less. 4 or less is more preferable, and 3 or less is more preferable. In particular, 2 or less is preferable. This gives a polyester with a low yellowness. Since the titanium compound and tin compound which are the preferable polycondensation catalyst system described above can obtain a polyester having a higher b value than the antimony compound and germanium compound which are polycondensation catalysts used for general purposes, the titanium compound When a tin compound or tin compound is used as the polycondensation catalyst, it is preferable to use a system that is improved so as to obtain a polyester having a low color tone b value modified by complexing with other compounds.

Further, it is known that a color tone adjusting agent is used in combination to improve the above yellowness, but it is also included in the scope of the present invention to adopt this method. The method for improving the color tone is not limited.
For example, it is a preferred embodiment to add a cobalt compound as a cobalt atom in an amount of less than 10 ppm with respect to the polyester for the purpose of improving color tone. More preferably, it is 5 ppm or less, More preferably, it is 3 ppm or less. The cobalt compound is not particularly limited, and specific examples include cobalt acetate, cobalt nitrate, cobalt chloride, cobalt acetylacetonate, cobalt naphthenate, and hydrates thereof. Of these, cobalt acetate tetrahydrate is particularly preferred.

  In order to improve the color tone of the polyester of the present invention, it is also a preferred embodiment to use a color tone improving agent other than the cobalt compound. The color tone improving agent refers to a substance that changes color tone when added. The color tone improving agent of the present invention is not particularly limited, but inorganic and organic pigments, dyes, fluorescent whitening agents and the like are preferable.

  When a pigment or a dye is used, when the amount used is increased, there arises a problem that the brightness of the polycondensate decreases as a result. This causes the problem of being unacceptable for many applications. Therefore, the total amount of pigments and dyes used is preferably 20 ppm or less, more preferably 10 ppm or less, still more preferably 5 ppm or less, based on the polyester obtained. In such a region, the coloring can be effectively eliminated without reducing the brightness of the polycondensate.

  Further, it is preferable to use a fluorescent brightening agent alone or in combination with another color tone improving agent because the color tone is improved and, for example, the amount of the pigment or dye used may be small. As the fluorescent brightening agent, one commonly used one may be used, or two or more kinds may be used in combination. The amount added is preferably 50 ppm or less, more preferably 5 to 25 ppm, based on the polyester obtained.

  The inorganic pigment of the present invention is not particularly defined as long as it can change the color tone, for example, titanium dioxide, carbon black, iron black, nickel titanium yellow, yellow iron oxide, cadmium yellow, chrome lead, chrome titanium yellow, Examples include zinc ferrite pigments, dials, cadmium red, molybdenum red, chromium oxide, spinel green, chrome orange, cadmium orange, ultramarine blue, bitumen, and cobalt blue. Of these, chromium oxide, ultramarine blue, bitumen, and cobalt blue are preferable, and ultramarine blue and cobalt blue are more preferable. One or more of these inorganic pigments may be used in combination as necessary.

  The organic pigments and dyes of the present invention are not specified as long as they can change the color tone, but, for example, Pigment Red 5, 22, 23, 31, 38, 48: 1, 48: 2 displayed by a color index. , 48: 3, 48: 4, 52, 53: 1, 57: 1, 122, 123, 144, 146, 151, 166, 170, 177, 178, 179, 187, 202, 207, 209, 213, 214 , 220, 221, 247, 254, 255, 263, 272, Pigment Orange 13, 16, 31, 36, 43, 61, 64, 71, Pigment Brown 23, Pigment Yellow 1, 3, 12, 13, 14, 17 , 55, 73 , 74, 81, 83, 93, 94, 95, 97, 109, 110, 128, 130, 133, 136, 138, 147, 150, 151, 154, 180, 181, 183, 190, 191, 191: 1 , 199, Pigment Green 7, 36, Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15.4, 15: 6, 29, 60, 64, 68, Pigment Violet 19, 23, 37, 44, Solvent Red 52, 117, 135, 169, 176, Disperse Red 5, Solvent Orange 63, 67, 68, 72, 78, Solvent Yellow 98, 103, 105, 113, 116, Di perseYellow 54, 64, 160, Solvent Green 3, 20, 26, Solvent Blue 35, 45, 78, 90, 94, 95, 104, 122, 132, Solvent Violet 31, and the like. Other anthraquinone, phthalocyanine, quinacridone, isoindolinone, dioxazine, quinophthalone, perylene, perinone, benzimidazolone, diarylide, bat, indigo, quinophthalone, diketopyrrolo Examples include pyrrole and anthrapyrrolidone dyes / pigments.

  Among these, Pigment Red 187, 263, Pigment Blue 15: 1, 15: 3, 29, 60, Pigment Violet 19, Solvent Red 135, Solvent Blue 45, 90, 104, 122, and anthraquinone and phthalocyanine dyes / Pigments are preferred. Furthermore, anthraquinone and phthalocyanine dyes / pigments are particularly preferred.

  The selected pigments and / or dyes preferably satisfy the following conditions. First, the pigments and dyes must be non-extractable from the polycondensate for maximum safety. It is stable to sunlight and a wide range of temperature and humidity conditions. Furthermore, it does not cause sublimation or hue changes as a result of the extremely high temperatures encountered during the production of polyester. Furthermore, it is preferable that these pigments and dyes do not adversely affect the physical properties of the polyester polymer.

  A pigment and / or a dye satisfying these conditions is not particularly limited as long as it improves the color tone of the polyester. For example, in Japanese Translation of PCT International Publication No. 2000-511111, a certain blue 1,4-bis (2,6-dialkylanilino) is used. ) Color tone improvers that mainly use anthraquinone and combine red anthraquinone and anthrapyridone (3H-dibenzo [fi, j] isoquinoline-2,7-dione) compounds according to the hue are exemplified. be able to. These dyes have suitable color characteristics, are stable to heat, light, humidity and various environmental factors and can be included in the polyester polymer structure during polycondensation, and are known organic dyes. Overcome many of the problems you encounter. It is stable to UV light, high temperature, glycolysis and hydrolysis. Furthermore, the amount of the blue component and the red component can be changed as necessary so as to work effectively for polyesters having different degrees of coloring.

  As the optical brightener of the present invention, those generally used may be used alone or in combination. For example, benzoxazoline-based fluorescent brighteners, preferably UVITEX OB, UVITEX OB-P, UVITEX OB-ONE, CHIARI Specialty Chemicals, Ltd., HOTALUX KS, manufactured by Clariant, and those described in JP-A-10-1563 Can be preferably used.

Since the above-described color tone improving agent achieves an achromatic hue, it can be used in any combination of types and addition ratios. Further, the color tone improving agent may be added at any stage of the polycondensation, after the polycondensation reaction, or at any stage from the end of the polycondensation reaction to the time of molding. . Further, the addition method is preferably added after dissolving in powder or one of polyester monomers during polycondensation. Furthermore, after completion of the polycondensation reaction, it is preferably added as a powder or a master batch.

  The above-described color tone improvement method is an effective method for improving the b value which is the yellowness, which is the above-described problem, but has the effect of reducing the color tone L value which is a measure of the brightness of the polyester as described above. ing. Accordingly, the polyester obtained in the present invention preferably has a color tone L value of 53 or more. 54 or more is more preferable, and 55 or more is more preferable. 56 or more is particularly preferable. This gives a polyester with high brightness.

The b value and L value, which are the color tone of the polyester, are affected by the shape and crystallinity of the polyester. Therefore, the above numerical values are measured by the following method.
The melted polyester is cooled and solidified in an amorphous state as a strand with a diameter of 3 ± 0.5 mm in water from a discharge nozzle, and the polyester chip obtained by cutting the strand with a length of 3 ± 0.5 mm is dried. To do. The polyester chip is measured for the L value and b value of the hunter using a color difference meter (manufactured by Tokyo Denshoku Co., Ltd .: Model ND-1001DP).

  When the color tone range is exceeded, use may be limited depending on the application.

  Among the preferred polycondensation catalyst systems described above, the composite polycondensation catalyst comprising an aluminum compound and a phosphorus compound can exhibit the effect that the reaction of increasing the degree of polymerization by the esterification reaction in the polycondensation reaction step is promoted. In addition, it is a particularly preferred embodiment because a polyester having excellent color tone can be obtained. Hereinafter, a composite polycondensation catalyst composed of an aluminum compound and a phosphorus compound, which is a particularly preferred polycondensation catalyst system, will be mentioned.

  The aluminum compound constituting the composite polycondensation catalyst is not limited, but aluminum formate, aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate , Carboxylates such as aluminum citrate, aluminum tartrate, aluminum salicylate, inorganic acid salts such as aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum phosphate, aluminum phosphonate, Aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum iso-propoxide, Aluminum alkoxide such as ruminium n-butoxide and aluminum t-butoxide, aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate, aluminum isochelate such as di-propoxide, trimethylaluminum, triethylaluminum Organic aluminum compounds and their partial hydrolysates, reaction products comprising aluminum alkoxides and aluminum chelate compounds and hydroxycarboxylic acids, aluminum oxide, ultrafine aluminum oxide, aluminum silicate, aluminum and titanium, silicon, zirconium, alkali metals, Examples thereof include complex oxides with alkaline earth metals. Of these, carboxylates, inorganic acid salts and chelate compounds are preferred, and among these, aluminum acetate, aluminum lactate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred.

  Among these aluminum compounds, aluminum acetate, aluminum chloride, aluminum hydroxide, and aluminum hydroxide chloride having a high aluminum content are preferable, and aluminum acetate, aluminum chloride, and aluminum hydroxide chloride are more preferable from the viewpoint of solubility. Furthermore, the use of aluminum acetate is particularly preferred from the viewpoint of not corroding the device.

Here, aluminum hydroxide chloride is a general term for what is generally called polyaluminum chloride or basic aluminum chloride, and those used for water supply can be used. These are represented by, for example, the general structural formula [Al ₂ (OH) _n Cl _6-n ] _m (where 1 ≦ n ≦ 5). Among these, those having a low chlorine content are preferable from the viewpoint of not corroding the device.

  The above-mentioned aluminum acetate is a general term for those having a structure of an aluminum salt of acetic acid represented by basic aluminum acetate, aluminum triacetate, aluminum acetate solution, etc. Among these, from the viewpoint of solubility and solution stability The use of basic aluminum acetate is preferred. Of the basic aluminum acetates, aluminum monoacetate, aluminum diacetate, or those stabilized with boric acid are preferred. When using the one stabilized with boric acid, it is preferable to use one stabilized with boric acid in an amount of equimolar or less with respect to basic aluminum acetate, and in particular, 1/2 to 1/3 molar amount. The use of basic aluminum acetate stabilized with boric acid is preferred. Examples of basic aluminum acetate stabilizers include urea and thiourea in addition to boric acid.

  The aluminum compound is preferably added in the form of a slurry or solution. The addition in the form of a solution is preferable from the viewpoint of the catalytic activity and the quality of the resulting polyester.

The method for dissolving the aluminum compound is exemplified below.
(1) Preparation example of aqueous solution of basic aluminum acetate Water is added to basic aluminum acetate and stirred at 50 ° C. or lower for 3 hours or longer. The stirring time is more preferably 6 hours or longer. Thereafter, stirring is performed at 60 ° C. or more for several hours or more. The temperature in this case is preferably in the range of 60 to 100 ° C. The stirring time is preferably 1 hour or longer. The concentration of the aqueous solution is preferably 10 g / l to 30 g / l, particularly preferably 15 g / l to 20 g / l.

(2) Preparation Example of Ethylene Glycol Solution of Basic Aluminum Acetate Ethylene glycol is added to the above aqueous solution. The amount of ethylene glycol added is preferably 0.5 to 5 times the volume ratio of the aqueous solution. More preferably, the amount is 1 to 3 times. The solution is stirred at room temperature for several hours to obtain a uniform water / ethylene glycol mixed solution. Thereafter, the solution is heated and water is distilled off to obtain an ethylene glycol solution. The temperature is preferably 80 ° C. or higher, and preferably 200 ° C. or lower. More preferably, the water is distilled off by stirring at 90 to 150 ° C. for several hours. The system may be depressurized during distillation. By reducing the pressure, ethylene glycol can be rapidly distilled off at a lower temperature. In other words, the distillation can be performed at 80 ° C. or lower under reduced pressure, and the heat history applied to the system can be further reduced.

(3) Preparation example of aluminum glycol solution of aluminum lactate An aqueous solution of aluminum lactate is prepared. The preparation may be performed at room temperature or under heating, but is preferably performed at room temperature. The concentration of the aqueous solution is preferably 20 g / l to 100 g / l, particularly preferably 50 to 80 g / l. Ethylene glycol is added to the aqueous solution. The amount of ethylene glycol added is preferably 1 to 5 times the volume ratio of the aqueous solution. More preferably, the amount is 2-3 times. After stirring the solution at room temperature to obtain a uniform water / ethylene glycol mixed solution, the solution is heated and water is distilled off to obtain an ethylene glycol solution. The temperature is preferably 80 ° C. or higher, and preferably 120 ° C. or lower. More preferably, the water is distilled off by stirring at 90 to 110 ° C. for several hours.

  The amount of the aluminum compound used is preferably 0.001 to 0.05 mol%, more preferably 0.005 to 0.03 mol%, based on the number of moles of all constituent units of the carboxylic acid component of the polyester obtained. It is. If the amount used is less than 0.001 mol%, the catalytic activity may not be sufficiently exerted. If the amount used is 0.05 mol% or more, thermal stability or thermal oxidation stability is lowered, resulting from aluminum. Occurrence of foreign matters or increased coloring may be a problem. Thus, even if the addition amount of the aluminum component is small, the polycondensation catalyst of the present invention has a great feature in that it exhibits sufficient catalytic activity. As a result, the thermal stability and thermal oxidation stability are excellent, and foreign matters and coloring caused by aluminum are reduced.

  Although it does not specifically limit as a phosphorus compound which comprises a composite polycondensation catalyst, Phosphate, phosphoric acid esters, such as trimethyl phosphoric acid, triethyl phosphoric acid, phenyl phosphoric acid, triphenyl phosphoric acid, phosphorous acid, and trimethyl phosphite , Triethyl phosphite, triphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylene diphosphite, etc. Examples thereof include phosphites.

  More preferable phosphorus compounds are at least one phosphorus compound selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as thermal stability of the polyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  The phosphonic acid-based compound, phosphinic acid-based compound, phosphine oxide-based compound, phosphonous acid-based compound, phosphinic acid-based compound, and phosphine-based compound referred to in the present invention are represented by the following formulas (Formula 1) to (Formula 6), respectively. It refers to a compound having the structure represented.

  Examples of the phosphonic acid compound of the present invention include dimethyl methylphosphonate, diphenyl methylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, diphenyl phenylphosphonate, dimethyl benzylphosphonate, diethyl benzylphosphonate and the like. Examples of the phosphinic acid compound of the present invention include diphenylphosphinic acid, methyl diphenylphosphinate, phenyl diphenylphosphinate, phenylphosphinic acid, methyl phenylphosphinate, phenylphenylphosphinate and the like. Examples of the phosphine oxide compound of the present invention include diphenylphosphine oxide, methyldiphenylphosphine oxide, and triphenylphosphine oxide.

  Among the phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds, the phosphorus compounds of the present invention are represented by the following formulas (Chemical Formula 7) to (Chemical Formula 12). Are preferred.

  Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  In addition, when the compounds represented by the following general formulas (Chemical Formula 13) to (Chemical Formula 15) are used as the phosphorus compound of the present invention, the physical property improving effect and the catalytic activity improving effect are particularly large and preferable.

Wherein R ¹ , R ⁴ , R ⁵ and R ⁶ are each independently hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an alkoxyl group or an amino group. Represents a hydrocarbon group having 1 to 50 carbon atoms including R ² and R ³ each independently represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms including a hydroxyl group or an alkoxyl group. However, the hydrocarbon group may contain an alicyclic structure such as cyclohexyl or an aromatic ring structure such as phenyl or naphthyl.)

The phosphorus compound of the present invention is particularly preferably a compound in which R ¹ , R ⁴ , R ⁵ , and R ⁶ are groups having an aromatic ring structure in the above formulas (Chemical Formula 13) to (Chemical Formula 15).

  Examples of the phosphorus compound of the present invention include dimethyl methylphosphonate, diphenyl methylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, diphenyl phenylphosphonate, dimethyl benzylphosphonate, diethyl benzylphosphonate, diphenylphosphinic acid, diphenylphosphinic acid. Examples include methyl, phenyl diphenylphosphinate, phenylphosphinic acid, methyl phenylphosphinate, phenyl phenylphosphinate, diphenylphosphine oxide, methyldiphenylphosphine oxide, and triphenylphosphine oxide. Of these, dimethyl phenylphosphonate and diethyl benzylphosphonate are particularly preferred.

  Among the phosphorus compounds described above, a phosphorus metal salt compound is particularly preferable as the phosphorus compound in the present invention. The phosphorus metal salt compound is not particularly limited as long as it is a metal salt of a phosphorus compound. However, when a metal salt of a phosphonic acid compound is used, the physical properties improving effect and catalytic activity improving effect of the polyester, which are the problems of the present invention, are improved. Largely preferred. Examples of the metal salt of the phosphorus compound include a monometal salt, a dimetal salt, and a trimetal salt.

  Further, among the above-described phosphorus compounds, when the metal portion of the metal salt is selected from Li, Na, K, Be, Mg, Sr, Ba, Mn, Ni, Cu, and Zn, the catalytic activity is improved. Is preferable. Of these, Li, Na, and Mg are particularly preferable.

  As the phosphorus metal salt compound of the present invention, it is preferable to use at least one selected from the compounds represented by the following general formula (Chemical Formula 16) because the effect of improving the physical properties and the effect of improving the catalytic activity are large.

(In the formula (Formula 16), R ¹ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an alkoxyl group, or an amino group, and a hydrocarbon group having 1 to 50 carbon atoms. R ² represents , Hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxyl group, and a hydrocarbon group having 1 to 50 carbon atoms, R ³ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxyl group. A hydrocarbon group having 1 to 50 carbon atoms including a group or carbonyl, l is an integer of 1 or more, m is 0 or an integer of 1 or more, l + m is 4 or less, M is a (l + m) -valent metal Represents a cation, n represents an integer of 1 or more, and the hydrocarbon group may contain an alicyclic structure such as cyclohexyl, a branched structure, or an aromatic ring structure such as phenyl or naphthyl.)

Examples of R ¹ include phenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 4-biphenyl, 2-biphenyl, and the like. Examples of R ² include hydrogen, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, long-chain aliphatic group, phenyl group, naphthyl group, Examples thereof include a substituted phenyl group, a naphthyl group, and a group represented by —CH ₂ CH ₂ OH. Examples of R ³ O ⁻ include hydroxide ions, alcoholate ions, acetate ions, and acetylacetone ions.

  Among the compounds represented by the general formula (Chemical Formula 16), it is preferable to use at least one selected from the compounds represented by the following General Formula (Chemical Formula 17).

(In the formula (Chemical Formula 17), R ¹ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an alkoxyl group, or an amino group, and a hydrocarbon group having 1 to 50 carbon atoms. R ³ represents , Hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxyl group, or a hydrocarbon group having 1 to 50 carbon atoms including carbonyl, l is an integer of 1 or more, and m is 0 or an integer of 1 or more. , L + m is 4 or less, M represents a (l + m) -valent metal cation, and the hydrocarbon group may contain an alicyclic structure such as cyclohexyl or a branched structure, or an aromatic ring structure such as phenyl or naphthyl.

Examples of R ¹ include phenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 4-biphenyl, 2-biphenyl, and the like. Examples of R ³ O ⁻ include hydroxide ions, alcoholate ions, acetate ions, and acetylacetone ions.

  Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  Among the above formulas (Chemical Formula 17), when M is selected from Li, Na, K, Be, Mg, Sr, Ba, Mn, Ni, Cu, and Zn, the effect of improving the catalytic activity is large and preferable. Of these, Li, Na, and Mg are particularly preferable.

  Examples of the metal salt compound of phosphorus according to the present invention include lithium [ethyl (1-naphthyl) methylphosphonate], sodium [ethyl (1-naphthyl) methylphosphonate], magnesium bis [ethyl (1-naphthyl) methylphosphonate], potassium [ (2-naphthyl) methylphosphonate ethyl], magnesium bis [(2-naphthyl) methylphosphonate ethyl], lithium [benzylphosphonate ethyl], sodium [benzylphosphonate ethyl], magnesium bis [benzylphosphonate ethyl], beryllium bis [Ethyl benzylphosphonate], strontium bis [ethyl benzylphosphonate], manganese bis [ethyl benzylphosphonate], sodium benzylphosphonate, magnesium bis [benzylphosphonic acid], sodium [(9-anths L) ethyl methylphosphonate], magnesium bis [(9-anthryl) methylphosphonate ethyl], sodium [ethyl 4-hydroxybenzylphosphonate], magnesium bis [4-hydroxybenzylphosphonate ethyl], sodium [4-chlorobenzylphosphone] Acid phenyl], magnesium bis [4-chlorobenzylphosphonate ethyl], sodium [methyl 4-aminobenzylphosphonate], magnesium bis [4-aminobenzylphosphonate methyl], sodium phenylphosphonate, magnesium bis [phenylphosphonic acid] Ethyl], zinc bis [ethyl phenylphosphonate] and the like. Among these, lithium [ethyl (1-naphthyl) methylphosphonate], sodium [ethyl (1-naphthyl) methylphosphonate], magnesium bis [ethyl (1-naphthyl) methylphosphonate], lithium [ethyl benzylphosphonate], Sodium [ethyl benzylphosphonate], magnesium bis [ethyl benzylphosphonate], sodium benzylphosphonate and magnesium bis [benzylphosphonic acid] are particularly preferred.

Among the phosphorus compounds described above, in the present invention, a phosphorus compound having at least one P—OH bond is particularly preferable as the phosphorus compound. In addition to particularly enhancing the physical properties improving effect of the polyester by containing these phosphorus compounds, the catalytic activity is improved by using these phosphorus compounds in combination with the aluminum compound of the present invention at the time of polymerization of the polyester. Seen large.
The phosphorus compound having at least one P—OH bond is not particularly limited as long as it is a phosphorus compound having at least one P—OH in the molecule. Among these phosphorus compounds, the use of a phosphonic acid compound having at least one P—OH bond is preferred because of its great effect of improving the physical properties and improving the catalytic activity of the polyester.

  Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  As the phosphorus compound having at least one P—OH bond of the present invention, it is preferable to use at least one selected from the compounds represented by the following general formula (Chemical Formula 18) because the physical property improving effect and the catalytic activity improving effect are large. .

(In the formula (Chemical Formula 18), R ¹ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an alkoxyl group, or an amino group, and a hydrocarbon group having 1 to 50 carbon atoms. R ² represents , Hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms including a hydroxyl group or an alkoxyl group, n represents an integer of 1 or more, and the hydrocarbon group is an alicyclic structure such as cyclohexyl. And may contain an aromatic ring structure such as a branched structure or phenyl or naphthyl.)

Examples of R ¹ include phenyl, 1-naphthyl, 2-naphthyl, 9-anthryl, 4-biphenyl, 2-biphenyl, and the like. Examples of R2 include hydrogen, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, long-chain aliphatic group, phenyl group, naphthyl group, and substitution. And a phenyl group, a naphthyl group, a group represented by —CH ₂ CH ₂ OH, and the like.

  Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

  Examples of the phosphorus compound having at least one P—OH bond of the present invention include (1-naphthyl) methylphosphonic acid ethyl, (1-naphthyl) methylphosphonic acid, (2-naphthyl) methylphosphonic acid ethyl, benzylphosphonic acid ethyl, benzylphosphonic acid. Acid, ethyl (9-anthryl) methylphosphonate, ethyl 4-hydroxybenzylphosphonate, ethyl 2-methylbenzylphosphonate, phenyl 4-chlorobenzylphosphonate, methyl 4-aminobenzylphosphonate, ethyl 4-methoxybenzylphosphonate Etc. Of these, ethyl (1-naphthyl) methylphosphonate and ethyl benzylphosphonate are particularly preferred.

  A preferable phosphorus compound of the present invention is a phosphorus compound represented by the chemical formula (Formula 19).

(In the formula (Chemical Formula 19), R ¹ represents a hydrocarbon group having ¹ to 49 carbon atoms, or a hydrocarbon group having ¹ to 49 carbon atoms including a hydroxyl group, a halogen group, an alkoxyl group, or an amino group, and R ² , R ³ each independently represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or an alkoxyl group, which has an alicyclic structure, a branched structure or an aromatic ring structure. May be included.)

More preferably, at least one of R ¹ , R ² and R ^{3 in} the chemical formula (Chemical Formula 19) is a compound containing an aromatic ring structure.

  Specific examples of these phosphorus compounds are shown below.

  Moreover, since the phosphorus compound of the present invention has a large molecular weight, it is more effective because it is less likely to be distilled off during polymerization.

  The phosphorus compound of the present invention is preferably a phosphorus compound having a phenol moiety in the same molecule. In addition to enhancing the physical properties of polyester by containing a phosphorus compound having a phenol moiety in the same molecule, the effect of increasing catalytic activity by using a phosphorus compound having a phenol moiety in the same molecule during polyester polymerization Is larger, and therefore the polyester productivity is excellent.

  The phosphorus compound having a phenol moiety in the same molecule is not particularly limited as long as it is a phosphorus compound having a phenol structure, but a phosphonic acid compound, a phosphinic acid compound, a phosphine oxide compound having a phenol moiety in the same molecule. When one or more compounds selected from the group consisting of a compound, a phosphonous acid compound, a phosphinic acid compound, and a phosphine compound are used, the effect of improving the physical properties of the polyester and the effect of improving the catalytic activity are greatly preferred. Among these, when a phosphonic acid compound having one or two or more phenol moieties in the same molecule is used, the effect of improving the physical properties of the polyester and the effect of improving the catalytic activity are particularly large and preferable.

  As a phosphorus compound which has the phenol part of this invention in the same molecule | numerator, the compound represented by the following general formula (Formula 26)-(Formula 28) is preferable.

(In the formulas (Chemical Formula 26) to (Chemical Formula 28), R ¹ is a carbon having 1 to 50 carbon atoms including a phenol part, a substituent such as a hydroxyl group, a halogen group, an alkoxyl group, or an amino group, and a phenol part. Represents a hydrocarbon group having a number of 1 to 50. R ⁴ , R ⁵ and R ⁶ each independently represents a substituent such as hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an alkoxyl group or an amino group. Represents a hydrocarbon group having 1 to 50 carbon atoms, and R ² and R ³ are each independently hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, or an alkoxyl group. Represents a hydrocarbon group, provided that the hydrocarbon group may contain a branched structure, an alicyclic structure such as cyclohexyl, or an aromatic ring structure such as phenyl or naphthyl, and the ends of R ² and R ⁴ are bonded to each other. Moyo Yes.)

  Examples of the phosphorus compound having the phenol moiety of the present invention in the same molecule include p-hydroxyphenylphosphonic acid, dimethyl p-hydroxyphenylphosphonate, diethyl p-hydroxyphenylphosphonate, diphenyl p-hydroxyphenylphosphonate, bis (P-hydroxyphenyl) phosphinic acid, methyl bis (p-hydroxyphenyl) phosphinate, phenyl bis (p-hydroxyphenyl) phosphinate, p-hydroxyphenylphenylphosphinic acid, methyl p-hydroxyphenylphenylphosphinate, p- Phenyl hydroxyphenylphenylphosphinate, p-hydroxyphenylphosphinic acid, methyl p-hydroxyphenylphosphinate, phenyl p-hydroxyphenylphosphinate, bis (p-hydroxyphenyl Yl) phosphine oxide, tris (p- hydroxyphenyl) phosphine oxide, bis (p- hydroxyphenyl) methyl phosphine oxide, and the following formula (Formula 29), and the like compounds represented by to (Formula 32). Among these, a compound represented by the following formula (Chemical Formula 31) and dimethyl p-hydroxyphenylphosphonate are particularly preferable.

As a compound represented by the above formula (Chemical Formula 31), SANKO-220 (manufactured by Sanko Co., Ltd.) can be used.

  Among the phosphorus compounds having the phenol moiety of the present invention in the same molecule, at least one selected from a metal salt compound of a specific phosphorus represented by the following general formula (Formula 33) is particularly preferable.

(In Formula (Chemical Formula 33), R ¹ and R ² each independently represent hydrogen and a hydrocarbon group having 1 to 30 carbon atoms. R ³ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or R ⁴ represents a hydrocarbon group having 1 to 50 carbon atoms including an alkoxyl group, R ⁴ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group, an alkoxyl group, or a carbonyl group including carbonyl. Examples of R ⁴ O ⁻ include hydroxide ion, alcoholate ion, acetate ion, acetylacetone ion, etc. l is an integer of 1 or more, m is 0 or an integer of 1 or more, and l + m is 4 or less. M represents a (l + m) -valent metal cation, n represents an integer of 1 or more, and the hydrocarbon group includes an alicyclic structure such as cyclohexyl, a branched structure, and an aromatic ring structure such as phenyl or naphthyl. Moyo .)

  Among these, at least one selected from compounds represented by the following general formula (Formula 34) is preferable.

(In the formula (Chemical Formula 34), M ^{n +} represents an n-valent metal cation. N is 1, 2, 3, or 4)
Represents. )

  Among the above formulas (Chemical Formula 33) or (Chemical Formula 34), when M is selected from Li, Na, K, Be, Mg, Sr, Ba, Mn, Ni, Cu, Zn, the catalytic activity is improved. The effect is large and preferable. Of these, Li, Na, and Mg are particularly preferable.

  Specific phosphorus metal salt compounds of the present invention include lithium [3,5-di-tert-butyl-4-hydroxybenzylphosphonate], sodium [3,5-di-tert-butyl-4-hydroxybenzyl] Ethyl phosphonate], sodium [3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid], potassium [ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate], magnesium bis [3 , 5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl], magnesium bis [3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid], beryllium bis [3,5-di-tert- Methyl butyl-4-hydroxybenzylphosphonate], strontium bis [3,5-di-te t-butyl-4-hydroxybenzylphosphonate ethyl], barium bis [3,5-di-tert-butyl-4-hydroxybenzylphosphonate phenyl], manganese bis [3,5-di-tert-butyl-4- Ethyl hydroxybenzylphosphonate], nickel bis [3,5-di-tert-butyl-4-hydroxybenzylphosphonate], copper bis [3,5-di-tert-butyl-4-hydroxybenzylphosphonate] Zinc bis [3,5-di-tert-butyl-4-hydroxybenzylphosphonate] and the like. Among these, lithium [ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate], sodium [ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate], magnesium bis [ Ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate] is particularly preferred.

  Among the phosphorus compounds having the phenol moiety of the present invention in the same molecule, at least one selected from specific phosphorus compounds having at least one P—OH bond represented by the following general formula (Formula 35) is particularly preferable.

(In formula (Chemical Formula 35), R ¹ and R ² each independently represent hydrogen and a hydrocarbon group having 1 to 30 carbon atoms. R ³ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydroxyl group or A hydrocarbon group having 1 to 50 carbon atoms including an alkoxyl group is represented, and n represents an integer of 1 or more.
The hydrocarbon group may contain an alicyclic structure such as cyclohexyl, a branched structure, or an aromatic ring structure such as phenyl or naphthyl. )

  Among these, at least one selected from compounds represented by the following general formula (Formula 36) is preferable.

(In formula (Chemical Formula 36), R ³ represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms including a hydroxyl group or an alkoxyl group. The hydrocarbon group is a fatty acid such as cyclohexyl. (It may contain a ring structure, a branched structure, or an aromatic ring structure such as phenyl or naphthyl.)

Examples of R ³ include hydrogen, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, long-chain aliphatic group, phenyl group, naphthyl group, Examples thereof include a substituted phenyl group, a naphthyl group, and a group represented by —CH ₂ CH ₂ OH.

  Specific phosphorus compounds having at least one P-OH bond of the present invention include ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3,5-di-tert-butyl-4-hydroxy Methyl benzylphosphonate, isopropyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, phenyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3,5-di-tert-butyl Examples include octadecyl-4-hydroxybenzylphosphonate, 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid, and the like. Of these, ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate and methyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate are particularly preferred.

  Among the phosphorus compounds having the phenol moiety of the present invention in the same molecule, at least one phosphorus compound selected from specific phosphorus compounds represented by the following general formula (Formula 37) is preferable.

(In the above formula (Chemical Formula 37), R ¹ and R ² each independently represent hydrogen and a hydrocarbon group having 1 to 30 carbon atoms. R ³ and R ⁴ are each independently hydrogen and carbon atoms having 1 to 50 carbon atoms. Represents a hydrocarbon group having 1 to 50 carbon atoms including a hydrogen group, a hydroxyl group or an alkoxyl group, n represents an integer of 1 or more, and the hydrocarbon group is an alicyclic structure such as cyclohexyl, a branched structure, or an aromatic such as phenyl or naphthyl. It may contain a ring structure.)

  Among the above general formulas (Chemical Formula 37), it is preferable to use at least one compound selected from the compounds represented by the following General Formula (Chemical Formula 38) because the effect of improving the physical properties and improving the catalytic activity of the polyester are high.

(In the above formula (Chemical Formula 38), R ³ and R ⁴ each independently represents hydrogen, a hydrocarbon group having 1 to 50 carbon atoms, a hydrocarbon group having 1 to 50 carbon atoms including a hydroxyl group or an alkoxyl group. The group may contain an alicyclic structure such as cyclohexyl, a branched structure, or an aromatic ring structure such as phenyl or naphthyl.)

Examples of R ³ and R ⁴ include short chain aliphatic groups such as hydrogen, methyl and butyl groups, long chain aliphatic groups such as octadecyl, phenyl groups, naphthyl groups, substituted phenyl groups and naphthyl groups. An aromatic group such as a group, a group represented by —CH ₂ CH ₂ OH, and the like.

  Specific phosphorus compounds of the present invention include diisopropyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, di-n-butyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, Examples include dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate and diphenyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate. Of these, dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate and diphenyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate are particularly preferred.

  Among the phosphorus compounds having the phenol moiety of the present invention in the same molecule, a particularly desirable compound in the present invention is at least one phosphorus compound selected from compounds represented by chemical formulas (Chemical Formula 39) and (Chemical Formula 40).

  As the compound represented by the above chemical formula (Chemical Formula 39), Irganox 1222 (manufactured by Ciba Specialty Chemicals) is commercially available, and as the compound represented by the chemical formula (Chemical Formula 40), Irganox 1425 (Ciba Specialty Chemical) is available. Chemicals) is commercially available and can be used.

  In the present invention, it is a preferred embodiment that the phosphorus compound is preheated in at least one solvent selected from the group consisting of water and alkylene glycol. The treatment improves the polycondensation catalyst activity by using the above-mentioned phosphorus compound in combination with the above-mentioned aluminum or aluminum compound, and decreases the foreign matter forming property due to the polycondensation catalyst.

  The solvent used when heat-treating the phosphorus compound in advance is not limited as long as it is at least one selected from the group consisting of water and alkylene glycol, but it is preferable to use a solvent that dissolves the phosphorus compound. As the alkylene glycol, it is preferable to use glycol which is a constituent component of the target polyester such as ethylene glycol. The heat treatment in the solvent is preferably performed after dissolving the phosphorus compound, but may not be completely dissolved. Further, it is not necessary that the compound retains the original structure after the heat treatment, and the solubility in the solvent may be improved by the modification by the heat treatment.

  Although the temperature of heat processing is not specifically limited, It is preferable that it is the range of 20-250 degreeC. More preferably, it is the range of 100-200 degreeC. The upper limit of the temperature is preferably around the boiling point of the solvent used. Although the heating time varies depending on conditions such as temperature, the heating temperature is preferably in the range of 1 minute to 50 hours, more preferably 30 minutes to 10 hours, and even more preferably 1 to 5 hours. Range. The pressure of the heat treatment system may be normal pressure, higher or lower, and is not particularly limited. The concentration of the solution is preferably 1 to 500 g / l as a phosphorus compound, more preferably 5 to 300 g / l, and still more preferably 10 to 100 g / l. The heat treatment is preferably performed in an atmosphere of an inert gas such as nitrogen. The storage temperature of the solution or slurry after heating is not particularly limited, but is preferably in the range of 0 ° C to 100 ° C, and more preferably in the range of 20 ° C to 60 ° C. It is preferable to store the solution in an atmosphere of an inert gas such as nitrogen.

  When heat-treating a phosphorus compound in a solvent in advance, the aluminum of the present invention or a compound thereof may coexist. Alternatively, the aluminum of the present invention or a compound thereof may be added in a powder form, a solution form, or a slurry form to a phosphorus compound that has been previously heat-treated in a solvent. Furthermore, you may heat-process the solution or slurry after addition. The solution or slurry obtained by these operations can be used as the polycondensation catalyst of the present invention. As described in claim 2, 95% by mass or more is preferably added after being dissolved or dispersed in a solvent comprising a glycol component.

  As usage-amount of said phosphorus compound, 0.0001-0.1 mol% is preferable with respect to the number-of-moles of all the structural units of the carboxylic acid component of polyester obtained, and is 0.005-0.05 mol%. More preferably.

The compound polycondensation catalyst composed of the above aluminum compound and phosphorus compound may be added to the polyester production process either separately or simultaneously. When adding simultaneously, you may add from a separate addition port, and may add from the same addition port.
Moreover, you may mix and add both beforehand. When mixing and adding both in advance, the mixing conditions for mixing the two and the conditions after mixing may be adjusted, and the complex formation reaction between the aluminum compound and the phosphorus compound may be adjusted as appropriate. I do not care.

  When the above aluminum compound and the above phosphorus compound are used in combination, a highly practical polycondensation catalytic activity can be expressed, but a further small amount of alkali metal, alkaline earth metal and at least one selected from the compound are used. It is a preferred embodiment to coexist as the second metal-containing component. The coexistence of such a second metal-containing component in the catalyst system is effective in improving productivity by obtaining a catalyst component having an increased reaction rate in addition to an effect of suppressing the formation of diethylene glycol, and thus a higher reaction rate. .

  A technique of adding an alkali metal compound or an alkaline earth metal compound to an aluminum compound to obtain a catalyst having sufficient catalytic activity is known. When such a known catalyst is used, a polyester having excellent thermal stability can be obtained. However, a known catalyst used in combination with an alkali metal compound or an alkaline earth metal compound is added in an amount to obtain practical catalytic activity. However, when an alkali metal compound is used, the hydrolysis resistance of the resulting polyester is reduced and the amount of foreign matter resulting from the alkali metal compound is increased. Moreover, when used for a film, the film properties and the like deteriorate. In addition, when an alkaline earth metal compound is used in combination, the thermal stability of the obtained polyester is lowered when it is attempted to obtain practical activity, coloring due to heating is large, the amount of foreign matter generated is increased, and water resistance is increased. Degradability also decreases.

When adding an alkali metal, an alkaline earth metal and a compound thereof, the amount M (mol%) used is 1 × 10 ⁻⁶ or more and 0.1 or more relative to the number of moles of all polycarboxylic acid units constituting the polyester. It is preferably less than mol%, more preferably 5 × 10 ^{−6 to} 0.05 mol%, still more preferably 1 × 10 ^{−5 to} 0.03 mol%, and particularly preferably 1 × 10 10. ^{-5 to} 0.01 mol%. Since the addition amount of alkali metals and alkaline earth metals is small, it is possible to increase the reaction rate without causing problems such as deterioration of thermal stability, generation of foreign substances, coloring, deterioration of hydrolysis resistance, etc. is there. When the amount M of the alkali metal, alkaline earth metal, or compound thereof used is 0.1 mol% or more, the heat stability is deteriorated, the generation of foreign matter and coloring, and the hydrolysis resistance are problematic in product processing. A case occurs. When M is less than 1 × 10 ⁻⁶ , the effect is not clear even when added.

  In the present invention, the alkali metal and alkaline earth metal constituting the second metal-containing component preferably used in addition to the aluminum compound include Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba. Preferably, at least one selected from the group consisting of Li, Na, Mg and compounds thereof is more preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.

  Among these alkali metals, alkaline earth metals or their compounds, when using strongly alkaline ones such as hydroxides, these tend to be difficult to dissolve in diols such as ethylene glycol or organic solvents such as alcohols. However, it must be added to the polymerization system in an aqueous solution, which may cause a problem in the polymerization process. Furthermore, when a strongly alkaline material such as a hydroxide is used, the polyester is liable to undergo side reactions such as hydrolysis during the polymerization, and the polymerized polyester tends to be colored, and the hydrolysis resistance also decreases. Tend to. Accordingly, the alkali metal or their compounds or alkaline earth metals or their compounds suitable for the present invention are preferably saturated aliphatic carboxylates, unsaturated aliphatic carboxylates, aromatics of alkali metals or alkaline earth metals. Aromatic carboxylates, halogen-containing carboxylates, hydroxycarboxylates, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen phosphate, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid, bromic acid Selected inorganic acid salts, organic sulfonates, organic sulfates, chelate compounds, and oxides. Among these, from the viewpoint of ease of handling, availability, and the like, it is preferable to use an alkali metal or alkaline earth metal saturated aliphatic carboxylate, particularly acetate.

  In the present invention, the use of recycled raw materials such as terephthalic acid and ethylene glycol obtained by the chemical decomposition recovery method for recovered PET bottles is a preferred embodiment because it helps save resources and protects the environment.

  The polyester obtained by the method of the present invention is heated under reduced pressure or under an inert gas stream to further proceed with polycondensation, an oligomer such as a cyclic trimer contained in the polyester resin, acetaldehyde, etc. There are no restrictions on taking measures such as removing the by-products. Further, for example, it is possible to incorporate a treatment such as purifying a polyester resin by an extraction method such as a supercritical pressure extraction method to remove impurities such as the by-products.

  In the polyester of the present invention, other arbitrary polymers, antistatic agents, antifoaming agents, dyeability improving agents, dyes, pigments, matting agents, fluorescent whitening agents, stabilizers, antioxidants, other An additive may be contained. As antioxidants, aromatic amine-based and phenol-based antioxidants can be used, and as stabilizers, phosphoric acid and phosphate ester-based phosphorus-based, sulfur-based, amine-based stabilizers, etc. Can be used.

  These additives can be added at any stage during or after polymerization of the polyester, or at the time of molding the polyester. Which stage is suitable depends on the structure of the target polyester and the requirements of the resulting polyester. What is necessary is just to select suitably according to performance, respectively.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not restrict | limited to these Examples. In addition, the evaluation method was implemented with the following method.

1. Measurement of AVo of oligomer The oligomer was pulverized by a handy mill (pulverizer) without exhibiting drying. A sample of 1.00 g was precisely weighed and 20 ml of pyridine was added. Several grains of zeolite were added and dissolved by boiling for 15 minutes. Immediately after boiling and refluxing, 10 ml of pure water was added and allowed to cool to room temperature. Titration with N / 10-NaOH was performed using phenolphthalein as an indicator. Do the same for the blank without the sample. When the oligomer did not dissolve in pyridine, the reaction was carried out in benzyl alcohol. AVo (eq / ton) is calculated according to the following equation.
AVo = (A−B) × 0.1 × f × 1000 / W
(A = drop constant (ml), B = blank drop constant (ml), f = factor N / 10-NaOH, W = weight of sample (g))

2. Measurement of oligomer OHVo The oligomer was pulverized with a handy mill (pulverizer) without drying. 0.50 g of a sample was precisely weighed, 10 ml of an acetylating agent (acetic anhydride pyridine solution 0.5 mol / L) was added, and immersed in a water bath at 95 ° C. or higher for 90 minutes. Immediately after taking out from a water tank, 10 ml of pure water was added and it stood to cool to room temperature. Using phenolphthalein as an indicator was titrated with _{N / 5-NaOH-CH 3} OH solution. Do the same for the blank without the sample. In advance, 20 ml of N / 10-hydrochloric acid is titrated with an N / 5-NaOH-CH ₃ OH solution using phenolphthalein as an indicator, and the factor (F) of the solution is determined according to the following formula.
F = 0.1 × f × 20 / a
(F = factor of N / 10-hydrochloric acid, a = drop constant (ml))
OHVo (eq / ton) is calculated according to the following formula.
OHVo = {(B−A) × F × 1000 / W} + AVo
(A = titration constant (ml), B = blank titration constant (ml), F = factor of N / 5-NaOH—CH ₃ OH solution, W = weight of sample (g))

3. Calculation of OHV% It calculated according to the following formula from OHVo and AVO which were calculated | required by the said method.
OHV% = {OHVo / (OHVo + AVo)} × 100

Calculation of Pn It was calculated by the following formula.
Pn (average degree of polymerization) = [MW + 26−88 × [OHVo / (AVo + OHVo)]] / (192 + 44E)
However, MW (molecular weight (g / mol)) = 10 ⁶ × 2 / (AVo + OHVo) E = DEG / (EG + DEG) E is a diethylene glycol production mole fraction. DEG is the number of moles of diethylene glycol in the polymer, and EG is the number of moles of ethylene glycol.

5, Es%
It was calculated by the following formula from AVo, OHVo and Pn as determined by the above method.
Es% = {1-AVo / Pn × (AVo + OHVo)} × 100

6. Measurement of Intrinsic Viscosity (IV) Measurement was performed at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (60:40, weight ratio).

7. Color tone From the discharge nozzle, melted polyester is cooled and solidified in an amorphous state as a 3 ± 0.5 mm diameter strand in water, and the strand is cut to a length of 3 ± 0.5 mm to form a polyester chip. Dried. The polyester chip was measured for Hunter L and b values using a color difference meter (manufactured by Tokyo Denshoku Co., Ltd .: Model ND-1001DP).

Example 1
(1) Preparation of polycondensation catalyst solution (ethylene glycol solution of phosphorus compound)
After adding 2.0 liters of ethylene glycol to a flask equipped with a nitrogen introduction line and a cooling line at room temperature and normal pressure, stirring with 200 rpm in a nitrogen atmosphere, Irganox 1222 (Ciba 39) represented by -200 g of Specialty Chemicals) was added. Further, 2.0 liters of ethylene glycol was added, the jacket temperature was changed to 196 ° C., the temperature was raised, and the mixture was stirred under reflux for 60 minutes from the time when the internal temperature reached 185 ° C. or higher. Thereafter, the heating was stopped, the solution was immediately removed from the heat source, and the solution was cooled to 120 ° C. or less within 30 minutes while maintaining the nitrogen atmosphere. The mole fraction of Irganox 1222 in the obtained solution was 40%, and the mole fraction of the compound whose structure changed from Irganox 1222 was 60%.
(Aqueous solution of aluminum compound)
After adding 5.0 liters of pure water to a flask equipped with a cooling line at room temperature and normal pressure, 200 g of basic aluminum acetate having an insoluble content in water evaluated by the above evaluation method of 2600 ppm with stirring at 200 rpm was added. It was added as a slurry with pure water. Further, pure water was added so as to be 10.0 liters as a whole, and the mixture was stirred at room temperature and normal pressure for 12 hours. Thereafter, the jacket temperature was changed to 100.5 ° C., the temperature was raised, and the mixture was stirred under reflux for 3 hours from the time when the internal temperature reached 95 ° C. or higher. Stirring was stopped and the mixture was allowed to cool to room temperature.
(Ethylene glycol solution of aluminum compound)
A flask equipped with a distillation apparatus was charged with 2.0 liters of an aqueous solution of basic aluminum acetate and 2.0 liters of ethylene glycol prepared by the above method under normal temperature and normal pressure. After stirring at 200 rpm for 30 minutes, uniform water / ethylene glycol A mixed solution was obtained. The jacket temperature was then changed to 110 ° C. and the temperature was raised, and water was distilled off from the solution. When the amount of distilled water reached 2.0 liters, the heating was stopped and the mixture was allowed to cool to room temperature to obtain an ethylene glycol solution of an aluminum compound.
(2) Esterification reaction and polycondensation In-line consisting of one continuous esterification reaction tank and one polycondensation reaction tank, and having a high-speed stirrer in the transfer line from the esterification reaction tank to the polycondensation reaction tank Prepared by mixing 0.39 parts by mass of ethylene glycol with 1 part by mass of high-purity terephthalic acid in a continuous polyester production apparatus equipped with a mixer, and continuously supplying the slurry to the esterification reaction tank, reaction temperature The reaction was carried out at 280 ° C. and 100 kPa for an average residence time of 4 hours, and the ethylene glycol solution of the aluminum compound and the ethylene glycol solution of the phosphorus compound prepared by the above method were supplied from a different supply port from the slurry supply tank of the esterification reaction tank. 0.021 mol% as aluminum atom and phosphorus atom respectively for the acid component in the polyester Preliminary added 0.028 mole percent as continuously made to give AVo1000eq / ton, OHVo1050eq / ton, OHV 1% 51 mol%, the Es% 90 mol% and Pn5 oligomers. The oligomer is continuously transferred to a continuous polycondensation apparatus consisting of one reaction tank, and continuously added to an in-line mixer installed in the transfer line so that ethylene glycol OHV ₂ % is 57 mol%. Then, polycondensation was conducted at a reaction temperature of 275 to 270 ° C. and an average reaction pressure of 26 Pa to obtain PET having an IV of 0.65. The results are shown in Table 1.

Comparative Example 1
A slurry prepared by mixing 0.39 parts by mass of ethylene glycol with 1 part by mass of high-purity terephthalic acid in a continuous polyester production apparatus comprising two continuous esterification reaction tanks and one polycondensation reaction tank. Aluminum continuously supplied to the esterification reaction tank, reacted at a reaction temperature of 280 ° C. and 100 kPa for an average residence time of 4 hours, and prepared by the above method from a supply port different from the slurry supply tank of the esterification reaction tank An ethylene glycol solution of the compound and an ethylene glycol solution of the phosphorus compound were continuously added so as to be 0.021 mol% and 0.028 mol% as aluminum atoms and phosphorus atoms, respectively, with respect to the acid component in the polyester. / ton, OHVo1050eq / ton, OHV 1% 51 mol%, Es% 0 to obtain an oligomer of mole% and Pn5. The oligomer was continuously extracted and transferred to the second esterification reactor. A static mixer was provided in the piping portion of the transfer line immediately before the second esterification reaction tank, and 0.025 parts by mass of ethylene glycol was added to and mixed with the static mixer portion. The oligomer to which ethylene glycol was added was supplied as it was to the second esterification reaction tank and reacted at a reaction temperature of 280 ° C. and kPa for an average residence time of 2 hours. The reaction product was introduced into a continuous polycondensation apparatus comprising one reaction tank, and polycondensed at a reaction temperature of 275 to 270 ° C. and an average reaction pressure of 26 Pa to obtain PET having an IV of 0.65. The characteristic values of the oligomers at the outlet of the second esterification reactor were AVo215 eq / ton, OHVo865 eq / ton, OHV ₁ % 80 mol%, Es% 98 mol%, and Pn9. The results are shown in Table 1.

Comparative Example 2
The esterification reaction conditions were changed by the method of Example 1 to obtain an esterification reaction product of AVO1250eq / ton, OHVo890eq / ton, OHV ₁ % 42 mol%, Es% 88 mol% and Pn5. The polycondensation was carried out in the same manner as in Example 1 except that the amount of ethylene glycol added to the in-line mixer installed in the transfer line from the esterification reaction tank to the polycondensation reaction tank was changed to 49% OHV ₂ %. But the polycondensation is unstable and the specified IV
PET was not obtained.

Comparative Example 3
In the method of Example 1, polycondensation was performed in the same manner as in Example 1 except that the addition of ethylene glycol to the in-line mixer installed in the transfer line from the esterification reaction tank to the polycondensation reaction tank was stopped. The polycondensation was unstable and a predetermined IV PET could not be obtained.

Example 2
In the method of Example 1, the addition of ethylene glycol added to the in-line mixer installed in the transfer line from the esterification reaction tank to the polycondensation reaction tank was stopped, and the aluminum compound added to the esterification reaction tank The PET of Example 2 was obtained in the same manner as in Example 1 except that the addition location of the ethylene glycol solution and the ethylene glycol solution of the phosphorus compound was changed to the in-line mixer. The results are shown in Table 1.

Example 3
In the method of Example 1, (1) The amount of ethylene glycol when preparing a slurry comprising high-purity terephthalic acid and ethylene glycol to be supplied to the esterification reaction tank is changed to 0.42 parts by mass, (2) esterification Stopped the addition of ethylene glycol added to the in-line mixer installed in the transfer line from the reaction tank to the polycondensation reaction tank, and added the ethylene glycol solution of the aluminum compound and phosphorus compound added to the esterification reaction tank. PET of Example 3 was obtained in the same manner as Example 1 except that the place was changed to the in-line mixer and (3) the average residence time of the esterification reaction tank was changed to 4 hours 30 minutes. The results are shown in Table 1.

Example 4
In the method of Example 1, the addition of ethylene glycol that had been added to the in-line mixer installed in the transfer line from the esterification reaction tank to the polycondensation reaction tank was stopped, and 20 g of porous fine powder silica was added to the in-line mixer. A PET dispersed in Example 4 was obtained in the same manner as in Example 1 except that the slurry dispersed at a concentration of / l was continuously added so that the silica was 1000 ppm based on the polyester. The results are shown in Table 1.

Example 5
(1) Preparation of polycondensation catalyst solution 9.79 parts by mass of titanium (IV) tetraisopropylate and 0.80 parts by mass of tetraethoxysilane are dissolved in 100 parts by volume of pure ethanol (solution A). 10.27 parts by mass of distilled water is mixed with 100 parts by volume of pure ethanol (solution B). Solution A is charged and solution B is plucked at 22 ° C. within 30 minutes. A white precipitate is deposited. After stirring for 1 hour, the mixture is centrifuged and the residue is washed three times with distilled water. The product was vacuum dried at 70 ° C. to obtain a polycondensation catalyst comprising titanium dioxide / silicon dioxide coprecipitate.
(2) Esterification reaction and polycondensation In the method of Example 3, in place of the ethylene glycol solution of the aluminum compound and phosphorus compound, a polycondensation catalyst composed of the above titanium dioxide / silicon dioxide coprecipitate was dispersed in ethylene glycol. The PET of Example 5 was obtained in the same manner as in Example 3 except that the amount was changed to 40 ppm with respect to the polyester from which the titanium dioxide / silicon dioxide coprecipitate was obtained. The results are shown in Table 1.

Example 6
In the method of Example 5, a blue pigment, Solvent Blue 104 (manufactured by Elite International Trading), was added to the polycondensation catalyst dispersion composed of titanium dioxide / silicon dioxide coprecipitate so as to be 5.0 ppm with respect to the polyester. The PET of Example 6 was obtained in the same manner as in Example 3 except that the polycondensation catalyst dispersion solution was changed. The results are shown in Table 1.

  Comparative Example 1 is a method according to a conventionally known method, and by carrying out within the scope of the present invention, a polymer having a high degree of polymerization can be obtained in a shorter time with a simplified facility than that of a conventionally known one. Obtainable.

  The method for producing the polyester of the present invention can provide a polymer having a high degree of polymerization in a shorter time than conventionally known methods. Moreover, it can respond with the more simplified installation compared with the conventionally well-known thing. Therefore, the production cost of polyester can be drastically reduced as compared with a conventionally known production method, which greatly contributes to the industry.

Claims (6)

In the method for producing a polyester by polycondensing the product obtained by the esterification reaction of dicarboxylic acid and glycol, the ratio of the hydroxyl value to the total terminal groups of the reaction product at the outlet of the final esterification reaction tank is 45 to 70. The amount by which the ratio of the hydroxyl value with respect to all the terminal groups of the reaction product is 55 to 78 mol% in the transfer line for obtaining the esterification product of mol% and transferring the reaction product to the polycondensation reaction tank. A method for producing a polyester, comprising adding a glycol and subsequently performing a polycondensation reaction. The method for producing a polyester according to claim 1, wherein the esterification rate of the reaction product at the outlet of the final esterification reaction tank is 80 to 96 mol%, and the average degree of polymerization is 3 or more. The method for producing a polyester according to claim 1 or 2, wherein the number of esterification reaction tanks is one. Method for producing a polyester according to any one of claims 1 to 3, wherein the color tone b value of the polyester is 5 or less. The method for producing a polyester according to any one of claims 1 to 4, wherein the color tone L value of the polyester is 53 or more. The method for producing a polyester according to any one of claims 1 to 5, wherein a polycondensation catalyst comprising at least one selected from the group consisting of aluminum compounds and at least one selected from phosphorus compounds is used.