JP2010241974A - Method for producing polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester containing suppressed amount of ether compounds and having good hue. <P>SOLUTION: The polyester production method comprises esterification reaction or transesterification by using a polycarboxylic acid A or an ester-forming derivative of the polycarboxylic acid A and a polyol as raw materials and polycondensation reaction of the reaction product, wherein a polycarboxylic acid B is added to the system after completing the esterification reaction or after completing the transesterification. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for producing a polyester capable of improving the hue of polyester and suppressing the content of ether compounds produced in side reactions.

  Polyesters, especially polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, and polybutylene terephthalate are excellent in mechanical, physical, and chemical performance, so they can be used in fibers, films, and other molded articles. Widely used. However, polyesters such as polyethylene terephthalate and polyethylene naphthalate have a problem that coloring easily occurs due to thermal decomposition during polymerization.

  This problem is particularly noticeable when a titanium compound is used as a catalyst. Titanium compounds are known to be elements that promote the polycondensation reaction of esters, and titanium alkoxide, titanium tetrachloride, titanyl oxalate, orthotitanic acid, etc. are known as polycondensation catalysts. Many studies have been conducted in order to use a titanium compound as a polycondensation catalyst. However, when a conventional titanium-based catalyst is used as a polycondensation catalyst, although it is more active than antimony compounds and germanium compounds, there arises a problem that the obtained polyester is remarkably colored yellow.

  In order to solve such problems, it is generally performed to suppress yellowness by adding a cobalt compound to an aromatic polyester, or by adding an additive such as an antioxidant. Yes. Certainly, the hue (b value) of the aromatic polyester can be improved by adding the cobalt compound, but the addition of the cobalt compound decreases the melt heat stability of the aromatic polyester, and also causes the thermal decomposition of the polymer. There is a problem that it tends to occur. In addition, for molecular weight reduction due to heat degradation during heat melting, in order to ensure the molecular weight required after heat melting, the molecular weight of the pellet before heat melting is increased in advance in anticipation of the molecular weight decrease that occurs during heat melting. However, it is not always efficient from the viewpoint of productivity such as energy (see, for example, Patent Document 1).

  Further, it is known that the content of the ether compound produced by the side reaction of the polyol component during the polycondensation reaction has an important influence on each application. For example, when polyethylene terephthalate is used as a bottle, it is desirable to contain a certain amount of diethylene glycol in order to ensure transparency, but if it is too much, the heat resistance is lowered, the crystallization promoting effect is lowered, and the gas barrier property is reduced. Such as damage. Specifically, the content of diethylene glycol constituting the polyethylene terephthalate resin must be 0.5 to 2.0 wt%, preferably 0.8 to 1. wt% with respect to all diol units constituting the polyethylene terephthalate. It is 7 wt%, more preferably in the range of 1.0 to 1.5 wt%.

  Moreover, when using a polyethylene terephthalate as a fiber, if the diethylene glycol concentration is less than 0.4 mol%, the dyeability is poor. On the other hand, when the diethylene glycol concentration is higher than 2.0 mol%, the dyeability is excellent, but not only the fiber strength is decreased, but also the weather resistance is deteriorated. The concentration of diethylene glycol incorporated into the main chain should be 0.4 to 2.0 mol%, preferably 0.5 to 1.2 mol%, more preferably 0.6 to 1.0 mol%.

  As a method of adjusting the diethylene glycol content within the above range, diethylene glycol is used as a polymerization raw material, and diethylene glycol is partially produced as a by-product from ethylene glycol used as a main raw material. The method of adjusting is mentioned.

  As a result, when the ether concentration contained in the polymer is insufficient, it can be supplemented by adding in any process of polycondensation. However, if the side reaction in the polycondensation process produces an excess of the target value, there are means such as lowering the reaction temperature, reducing the amount of catalyst added, adding a compound such as a radical scavenger, etc. There are problems such as lowering, adversely affecting the quality and reactivity due to the addition of unnecessary compounds, and worsening safety during use. As in the present invention, there is no known means for suppressing the amount of by-produced ethers while improving the quality of the polymer without adding an originally unnecessary compound.

  A method for producing a copolyester having improved quality and productivity by increasing the acidity in the system and increasing the polymerization rate by adding a polycarboxylic acid to an oligomer that satisfies a specific condition is disclosed. (For example, refer to Patent Document 2). However, it is difficult to produce a homopolymer because there are limitations on the polycarboxylic acid that can be used, for example, the melting point must be 400 ° C. or lower or the amorphous polycarboxylic acid.

  Furthermore, when it is necessary to remove aldehydes and cyclic oligomers which are decomposition products or to increase the intrinsic viscosity, a method in which melt-polycondensed polyester is subjected to solid-phase polycondensation is common. However, when a polycarboxylic acid ester is used as a raw material, it is necessary to add a large amount of a polycarboxylic acid having a melting point of 400 ° C. or less or amorphous during the reaction. A large amount is expected to remain. When such a polyester is subjected to solid phase polymerization, it is known that the solid phase polymerization rate is remarkably slow and the productivity is remarkably inferior.

Japanese Patent Publication No.57-085818 JP 2006-291030 A

  In light of the above-mentioned background art, the problem to be solved by the present invention is to provide a method for producing a polyester having a good hue and a reduced ether compound content.

  The present inventors paid attention to the fact that radicals are generated by thermal decomposition when a polyalkylene glycol is used as a polyol component during the polymerization reaction of polyester (see Patent Document 1). That is, it is considered that the generated radicals cause chain decomposition of the polymer and deterioration of the hue. For example, when ethylene glycol is used as a polyol, it is considered that diethylene glycol is generated from radicals generated from ethylene glycol.

  Therefore, the inventors have added a polycarboxylic acid to block the hydroxyl group end in the polyester polymerization step, thereby suppressing the generation of radicals, improving the hue, and the amount of diethylene glycol generated. Succeeded in suppressing. As the polycarboxylic acid to be added during the process, any compound such as isophthalic acid or trimellitic acid can be selected according to the purpose. In particular, when the same compound as the polycarboxylic acid used for the main chain is added, a polyester containing a good hue and an appropriate amount of ethers can be obtained without affecting the physical properties of the resulting polyester.

  That is, the present invention relates to polycarboxylic acid A or an ester-forming derivative of polycarboxylic acid A and a polyester production method in which a polyol is used as a raw material for an esterification reaction or a transesterification reaction, and then a polycondensation reaction is completed. A method for producing a polyester characterized in that polycarboxylic acid B is added after or after completion of the transesterification reaction.

  According to the present invention, the content of the ether compound in the polyester can be suppressed without impairing the original properties of the polyester, and a polyester having a good hue can be provided. Fibers, films and sheets, resin molded products, foods It can be suitably used for packaging containers (bottles, containers, etc.) and non-food containers (pharmaceuticals, drinks, etc.).

(About the polyol component)
Examples of the polyol component used as a raw material in the production method of the present invention include alkylene glycol, specifically, ethylene glycol, trimethylene glycol, 1,2-propanediol, 1,4-butanediol (tetramethylene glycol). ), Neopentylene glycol, and hexamethylene glycol. At this time, for example, as other different glycol components, ethylene glycol, trimethylene glycol, 1,2-propanediol, 1,4-butanediol (tetramethylene glycol), neopentylene glycol, pentamethylene glycol, hexamethylene glycol, 1 of alkylene glycols such as heptamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol, dihydroxycyclohexane, cyclohexanedimethanol, diethylene glycol, triethylene glycol, poly (oxy) ethylene glycol, polytetramethylene glycol, polyalkylene glycol Two or more species may be mixed and used, and can be arbitrarily selected depending on the purpose.

Moreover, it is preferable in the manufacturing method of polyester of this invention that a polyol is a compound represented by the following general formula (I).
HO— (CH ₂ ) n —OH 2 ≦ n ≦ 4 (I)
That is, it is preferable to use ethylene glycol, trimethylene glycol, or tetramethylene glycol.

  Further, a trifunctional or higher polyfunctional compound such as glycerin, trimethylolpropane, pentaerythritol and the like may be copolymerized within a range in which the polymer chain constituting the copolymerized aromatic polyester is substantially linear. Moreover, you may use a monofunctional compound, for example, decyl alcohol, dodecyl alcohol, 2-phenylethanol etc. as needed.

(About polycarboxylic acid A)
Examples of the polycarboxylic acid A used in the present invention include aromatic dicarboxylic acids. Specific examples include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and diphenyldicarboxylic acid. Examples thereof include aromatic dicarboxylic acids such as acid, diphenoxybutane dicarboxylic acid, diphenylthioether dicarboxylic acid, benzophenone dicarboxylic acid, and diphenylsulfone dicarboxylic acid. At this time, for example, as other different polycarboxylic acid components, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,7-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid; hexahydroterephthalic acid An alicyclic dicarboxylic acid such as a dicarboxylic acid component such as sebacic acid, azelaic acid, decanedicarboxylic acid, etc., or a mixture of two or more dicarboxylic acid components may be used. Can be selected arbitrarily.

  Further, a polyfunctional compound having a valence of 3 or more, such as trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid or gallic acid, within the range in which the polymer chain constituting the copolymerized aromatic polyester is substantially linear May be copolymerized. Moreover, you may use a monofunctional compound, for example, benzoic acid, toluic acid, 1-naphthoic acid, 2-naphthoic acid, о-benzoyl benzoic acid etc. as needed. Furthermore, a small amount of hydroxycarboxylic acid such as lactic acid, glycolic acid, hydroxybenzoic acid, or an alkyl ester thereof may be used.

  In the present invention, an ester-forming derivative of polycarboxylic acid A can also be used. Examples of the ester-forming derivative include acid anhydrides, lower alkyl esters, lower aryl esters, and acid halides of the above-described polycarboxylic acids. Examples of the lower alkyl ester include methyl ester, ethyl ester, n-propyl ester, iso-propyl ester, n-butyl ester, sec-butyl ester, t-butyl ester, n-pentyl ester, hexyl ester and hydroxyethyl ester. be able to. In addition, the lower aryl ester is phenyl ester, methyl phenyl ester, ethyl phenyl ester, propyl phenyl ester, butyl phenyl ester, methoxy phenyl ester, ethoxy phenyl ester, propyloxy phenyl ester, butyloxy phenyl ester, monofluorophenyl ester, Examples thereof include monochlorophenyl ester, monobromophenyl ester, difluorophenyl ester, dichlorophenyl ester, dibromophenyl ester, and naphthyl ester. Furthermore, acid halides and acid bromides can be mentioned as acid halides. When two or more carboxyl groups are present in one molecule of the polycarboxylic acid A, a functional group such as an ester group is provided for each carboxyl group as long as there is no problem with the stability of the compound at room temperature and normal pressure. The types may be different or the same. Among these, ester-forming derivatives of terephthalic acid or naphthalenedicarboxylic acid are particularly preferable. More specifically, terephthalic acid, dimethyl ester of naphthalenedicarboxylic acid, diethyl ester, di-n-butyl ester, diphenyl ester or bis (hydroxy Ethyl ester). Further, it is preferable to use an ester-forming derivative of polycarboxylic acid A rather than using the above-mentioned polycarboxylic acid A. That is, it is preferable to use an ester-forming derivative of polycarboxylic acid A and a polyol as raw materials.

(About polycarboxylic acid B added in the middle)
In the production method of the present invention, after completion of the esterification reaction or after the completion of the transesterification reaction, it is a point for achieving the object of the present invention to add polycarboxylic acid B and perform polycondensation. Examples of the polycarboxylic acid B that can be used in this case include aromatic dicarboxylic acids such as diphenoxyethane dicarboxylic acid and diphenyl ether dicarboxylic acid in addition to the compounds exemplified as the above polycarboxylic acid A; cyclohexanedicarboxylic acid (other than 1,4-) Examples thereof include alicyclic dicarboxylic acids such as acids, and fatty acid dicarboxylic acids such as adipic acid and sebacic acid. However, when charged into the oligomer in a high temperature state, a sublimable polycarboxylic acid such as dimethyl terephthalate may be undesirable because it causes clogging of the distillation piping and the pressure reducing port. The polycarboxylic acid B added in the polycondensation reaction is preferably the same type of polycarboxylic acid as the polycarboxylic acid A in order to prevent other components from being copolymerized with the polyester and the physical properties from deteriorating.

  The mechanism of action that can achieve the object of the present invention is not completely elucidated, but is considered as follows. That is, by adding a polycarboxylic acid having a faster transesterification rate than the polyester or polyester oligomer during the polycondensation reaction, the ester exchange reaction proceeds with the polyol group terminal of the polyester or polyester oligomer. The reason why the transesterification reaction rate is fast is considered to be because the molecular weight is small and the diffusion rate is faster than that of polyester or polyester oligomer. This phenomenon is thought to reduce the generation of radicals caused by the thermal decomposition of polyol groups, suppress the chain decomposition of polyester, improve the hue of the resulting polyester, and suppress the generation of ethers. .

  The polycarboxylic acid B can be added at any stage of the reaction process, but it is desirable to add it at a stage where the molecular weight has not increased so much. This is because the decomposition reaction proceeds with the addition of polycarboxylic acid B. In the production method of the present invention, in the polyester production method in which an esterification reaction or a transesterification reaction is performed using a polyol as a raw material, and then a polycondensation reaction is performed, It is necessary to add acid B. More preferably, it includes a step of bringing the state of 5 kPa or less in the polycondensation reaction, and the time for adding the polycarboxylic acid B in the polycondensation reaction is before the state of 1 kPa or less. This is from the viewpoint of suppressing the progress of the aforementioned decomposition reaction. The completion of the transesterification reaction step can be detected by the amount of by-products such as methanol and water generated in the reaction.

  Moreover, it is preferable that the quantity of polycarboxylic acid B added in this polycondensation reaction is 1.0 mol%-50.0 mol% with respect to 1 mol of polycarboxylic acid A of a raw material. More preferably, it is 1.5-30.0 mol%, More preferably, it is 1.8-28.0 mol%. The effect of the present invention can be achieved only by adding this amount at the above-mentioned time.

(About other third ingredients)
Examples of the copolymer component include diols containing aromatic groups such as bis (hydroxymethyl) naphthalene, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, and bis (hydroxymethyl) benzene.

(Production method: esterification reaction or transesterification reaction)
In the liquid phase polycondensation step (a), the polycarboxylic acid A or the ester-forming derivative thereof as described above and a polyol are subjected to an esterification reaction or a transesterification reaction, and then the obtained product is used. Polyester is produced by polycondensation reaction. In this liquid phase polycondensation step, usually, polycarboxylic acid A or the like and polyol are first esterified [esterification reaction step (a-1)], and then liquid phase polycondensation. A condensation reaction [polycondensation reaction step (a-2)] is carried out.

  As a specific example, first, a diester of polycarboxylic acid A and a polyol are supplied to the esterification reaction step (a-1). At this time, 1.02 to 3.0 mol of polyol is used with respect to 1 mol of polycarboxylic acid A. If necessary, it is preferable to add 1.0 to 60.0 mmol% of the above-described transesterification catalyst with respect to 1 mol of polycarboxylic acid A. If the transesterification catalyst is less than 1 mmol% relative to the polycarboxylic acid A component, the transesterification reaction will be insufficient, and the subsequent liquid phase polycondensation reaction and solid phase polycondensation reaction rate may be reduced. If the transesterification catalyst is added in excess of 60 mmol% with respect to the polycarboxylic acid A component, when the polyester obtained due to the influence of the precipitated particles due to the catalyst residue is molded into, for example, a bottle, the intrinsic viscosity is greatly reduced, which is not preferable. Sometimes. The transesterification reaction is usually performed under a reaction temperature of 190 to 280 ° C, preferably 200 to 260 ° C.

  In this case, it is necessary to use a transesterification catalyst. A compound containing a metal element such as an alkali metal compound, an alkaline earth metal compound, zinc, cobalt, magnesium, or tin can be used. An oxide, acetate, carbonate, etc. can be mentioned. Since it is easily available, acetate can be preferably employed. A specific compound group will be described later.

  When an ester-forming derivative of polycarboxylic acid A other than polycarboxylic acid A or an ester is used as a raw material for polyester, esterification reaction occurs instead of transesterification reaction. In particular, the case where polycarboxylic acid A is used can be typically carried out. Such an esterification reaction can also be carried out without adding additives other than polycarboxylic acid A and polyol. This is because the polycarboxylic acid A itself serves as a catalyst for the esterification reaction. Further, it can be carried out in the coexistence of a polycondensation catalyst described later. Further, tertiary amines such as trimethylamine, tri-n-butylamine and benzyldimethylamine, tetraethylammonium hydroxide, tetra-n-butyl hydroxide It can be carried out by adding a small amount of a basic compound such as quaternary ammonium such as ammonium or trimethylbenzylammonium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate, sodium hydroxide or potassium hydroxide. it can.

(Production method: melt polycondensation reaction)
The esterified product thus obtained is fed to a polycondensation reactor. In a liquid phase polycondensation reactor, the polycondensation is carried out while distilling off the resulting polyol etc. outside the reactor by heating to a temperature above the melting point of the resulting polyester under reduced pressure in the presence of a polycondensation catalyst. Is preferred. In the production method of the present invention, in the liquid phase polycondensation step (a) as described above, the intrinsic viscosity measured in o-chlorophenol at 25 ° C. is 0.80 to 1.50 dL / g, preferably 0. A polyester is produced that is 80 to 1.20 dL / g.

  The liquid phase polycondensation reaction as described above is performed in the presence of a polycondensation catalyst. As the polycondensation catalyst, germanium compounds such as germanium dioxide, germanium tetraethoxide or germanium tetra-n-butoxide, antimony compounds such as antimony trioxide, or titanium compounds such as titanium tetrabutoxide, titanium acetate or trimellitic acid titanium are used. be able to. These polycondensation catalysts can be added to the polycondensation reactor until the intrinsic viscosity reaches 0.30 dL / g.

  In this way, the polyester obtained from the final liquid phase polycondensation reactor is usually formed into granules (chips) by a melt extrusion molding method. The intrinsic viscosity of the obtained polyester needs to be 0.50 to 1.50 dL / g. When the intrinsic viscosity is less than 0.50 dL / g, for example, when the resulting polyester is molded into a bottle, not only is the strength as a bottle poor, but also the melt viscosity is low, which is inferior in terms of blow moldability. If it exceeds 1.50 dL / g, the melt viscosity is so high that it becomes difficult when injection molding the bottle preform, the molding temperature must be increased, and the coloring of the polymer becomes large, which is not preferable. In addition, the generation of aldehydes as decomposition products is increased, and there is a problem that the taste of the beverage filled after the bottle molding is impaired.

  In order to solve such problems, a general method is to increase the intrinsic viscosity by solid-phase polycondensation of melt-polycondensed polyester {prepolymer}. At that time, in order not to impair the physical properties of the finally obtained polyester, it is preferable to set the intrinsic viscosity of the prepolymer to a range of 0.50 to 0.90 dL / g. When the pre-polymer has an intrinsic viscosity of less than 0.50 dL / g, when chipping the polymer after completion of the melt polycondensation reaction, cracking chips frequently occur, the uniformity of the shape is lost and the polymer quality after the solid-phase polycondensation reaction is improved. This is not preferable in that not only variation occurs but also the load on solid-phase polycondensation increases and productivity decreases. When the prepolymer has an intrinsic viscosity exceeding 0.90 dL / g, it is not preferable from the viewpoint of generation of aldehydes due to coloring and decomposition in the melt polycondensation stage as described above. The solid phase polymerization step will be described later.

  Furthermore, it is possible to add a phosphorus compound in order to deactivate the transesterification catalyst or the polycondensation catalyst. The addition amount of the phosphorus compound is preferably 0.1 to 10 mol times the total number of moles of the transesterification catalyst or polycondensation catalyst (which may be a single species or a plurality of species). . When the addition amount is less than 0.1 mole times, the catalyst is not sufficiently deactivated, which may cause problems in terms of thermal stability and hue. On the other hand, if the amount added exceeds 10 moles, a problem may occur in terms of thermal stability.

(About transesterification catalyst)
Examples of the transesterification catalyst include lithium, sodium, potassium, rubidium, magnesium, calcium, strontium, barium and the like as general alkali metal and / or alkaline earth metal catalysts. Specific examples of such a catalyst include sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium hydrogen carbonate, lithium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, lithium carbonate, potassium carbonate, sodium acetate, lithium acetate, Potassium acetate, sodium borohydride, lithium borohydride, potassium borohydride, sodium stearate, lithium stearate, potassium stearate, sodium benzoate, lithium benzoate, potassium benzoate, disodium salt of bisphenol A, 2 Alkali metal compounds such as lithium salt, dipotassium salt, sodium salt of phenol, lithium salt, potassium salt, calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate List alkaline earth metal compounds such as magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, magnesium stearate, strontium stearate, etc. Can do. These may be used alone or in combination of two or more.

(About polycondensation catalyst)
For example, as a polycondensation catalyst, germanium dioxide, germanium tetraethoxide, germanium compounds such as germanium tetra-n-butoxide, antimony catalysts such as antimony trioxide, or titanium compounds such as titanium tetrabutoxide can be used. These polycondensation catalysts can be added to the polycondensation reactor until the intrinsic viscosity reaches 0.30 dL / g. Among these catalysts, it is preferable to use a titanium catalyst.

  Titanium compounds include titanium tetrabutoxide and their condensates (hexabutoxy dititanate, octabutoxy trititanate), titanium tetraisopropoxide, titanium tetranormal propoxide, titanium tetraethoxide, titanium tetramethoxide, titanium tetrakisacetyl. Acetonate complex, titanium tetrakis (2,4-hexanedionate) complex, titanium tetrakis (3,5-heptanedionate) complex, titanium dimethoxybisacetylacetonate complex, titanium diethoxybisacetylacetonate complex, titanium diisopropoxybis Acetylacetonate complex, titanium dinormal propoxybisacetylacetonate complex, titanium dibutoxybisacetylacetonate complex, titanium dihydroxybisglycolate, titanium Hydroxybislactate, Titanium dihydroxybis (2-hydroxypropionate), Titanium lactate, Titanium octanediolate, Titanium dimethoxybistriethanolamate, Titanium diethoxybistriethanolamate, Titanium dibutoxybistriethanolamate, Hexamethyldi Titanate, hexaethyl dititanate, hexapropyl dititanate, hexabutyl dititanate, hexaphenyl dititanate, octamethyl trititanate, octaethyl trititanate, octapropyl trititanate, octabutyl trititanate, octaphenyl trititanate, hexaalkoxy dititanate Examples thereof include titanate, octaalkyltrititanate, titanium acetate, and titanium trimellitic acid. Moreover, the reaction product of the above-mentioned tetraalkyl titanate and aromatic polycarboxylic acid or its anhydride, the reaction product of tetraalkyl titanate and monoalkyl phosphate or monoaryl phosphate may be sufficient.

  Examples of the germanium compound include germanium monoxide and germanium dioxide. Examples of the antimony compound include antimony trioxide and antimony acetate.

(About stabilizer)
The above polycondensation reaction can be carried out in the presence of a stabilizer as required. Stabilizers include trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, tri-iso-propyl phosphate, tri-n-butyl phosphate, tri-sec-butyl phosphate, tri-t-butyl phosphate, trihexyl phosphate, Phosphate esters such as trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tridodecyl phenyl phosphate, triphenyl phosphate, tricresyl phosphate, triphenyl phosphate, tris dodecyl phosphate, trisnonyl phenyl phosphate Phosphate esters, methyl acid phosphate, ethyl acid phosphate, normal propyl acid phosphate, isopropyl acid phosphate Acid phosphate esters such as phosphate, butyl acid phosphate, dimethyl phosphate, diethyl phosphate, di-n-propyl phosphate, di-iso-propyl phosphate, dibutyl phosphate, dihexyl phosphate, dioctyl phosphate and phosphoric acid, polyphosphoric acid, carbohydrate Methoxymethanephosphonic acid, carboethoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carbopropoxymethanephosphonic acid, carbomethoxy-phosphono-phenylacetic acid, carboethoxy-phosphono-phenylacetic acid, carboprotoxy-phosphono-phenylacetic acid and carbobutoxy -Phosphorous compounds selected from phosphono-phenylacetic acid dimethyl esters, diethyl esters, dipropyl esters and dibutyl esters It is. Of these, diethyl ester (triethylphosphonoacetate) of carboethoxymethanephosphonic acid is preferable. These phosphorus compounds may be used singly or in a plurality of types, or may be used in the form of a reaction product obtained by reacting the above-described titanium compound or germanium compound under a certain temperature condition as necessary.

  Furthermore, it is also possible to add a phosphorus compound separately from the above-mentioned stabilizer in order to deactivate the transesterification catalyst or polycondensation catalyst. The addition amount of the phosphorus compound is preferably 0.1 to 10 mol times the total number of moles of the transesterification catalyst or polycondensation catalyst (which may be a single species or a plurality of species). . When the addition amount is less than 0.1 mole times, the catalyst is not sufficiently deactivated, which may cause problems in terms of thermal stability and hue. On the other hand, if the amount added exceeds 10 moles, a problem may occur in terms of thermal stability.

  As the phosphorus compound, orthophosphoric acid, phosphoric acid monoester, phosphoric acid diester, phosphoric acid triester or the like is used, and in particular, at least one hydroxyl group of trimethyl phosphate or orthophosphoric acid is substituted with a hydroxyalkyl group or hydroxy (poly (polyester). A phosphate ester substituted with an (alkylene glycol) group is preferred. These phosphorus compounds are preferably added until the intrinsic viscosity of the reaction product reaches 0.60 dL / g. The stabilizer as described above should be added in an amount of 0.1 to 10 mol times the total number of moles of the transesterification catalyst or polycondensation catalyst (which may be single or plural). Is preferred. When the addition amount is less than 0.1 mole times, the catalyst is not sufficiently deactivated, which may cause problems in terms of thermal stability and hue. On the other hand, if the amount added exceeds 10 moles, a problem may occur in terms of thermal stability.

(Other additives)
If necessary, other additives such as colorants (coloring agents) such as cobalt acetate, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, alkali metals or alkaline earth metals and their compounds are selected. At least one kind may be used.

  The alkali metal compound used in the present invention is not limited to the following, but specifically, potassium chloride, potassium alum, potassium formate, tripotassium citrate, dipotassium hydrogen citrate, dicitrate dicitrate. Potassium hydrogen, potassium gluconate, potassium succinate, potassium butyrate, dipotassium oxalate, potassium hydrogen oxalate, potassium stearate, potassium phthalate, potassium hydrogen phthalate, potassium metaphosphate, potassium malate, tripotassium phosphate, Dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium nitrite, potassium benzoate, potassium hydrogen tartrate, potassium bioxalate, potassium biphthalate, potassium bitartrate, potassium bisulfate, potassium nitrate, potassium acetate, potassium carbonate, carbonic acid Potassium sodium, hydrogen carbonate Lithium, potassium lactate, potassium sulfate, potassium hydrogen sulfate, potassium hydroxide, sodium hydroxide, sodium chloride, sodium formate, trisodium citrate, disodium hydrogen citrate, sodium dihydrogen citrate, sodium gluconate, sodium succinate , Sodium butyrate, disodium oxalate, sodium hydrogen oxalate, sodium stearate, sodium phthalate, sodium hydrogen phthalate, sodium metaphosphate, sodium malate, trisodium phosphate, disodium hydrogen phosphate, dihydrogen phosphate Sodium, sodium nitrite, sodium benzoate, sodium hydrogen tartrate, sodium bioxalate, sodium biphthalate, sodium bitartrate, sodium bisulfate, sodium nitrate, sodium acetate, sodium carbonate Sodium bicarbonate, sodium lactate, sodium sulfate, sodium hydrogen sulfate, lithium hydroxide, lithium chloride, lithium formate, trilithium citrate, dilithium hydrogen citrate, lithium dihydrogen citrate, lithium gluconate, lithium succinate, butyric acid Lithium, dilithium oxalate, lithium hydrogen oxalate, lithium stearate, lithium phthalate, lithium hydrogen phthalate, lithium metaphosphate, lithium malate, trilithium phosphate, dilithium hydrogen phosphate, lithium dihydrogen phosphate, Lithium nitrite, lithium benzoate, lithium hydrogen tartrate, lithium deuterate, lithium biphthalate, lithium bitartrate, lithium bisulfate, lithium nitrate, lithium acetate, lithium carbonate, lithium hydrogen carbonate, lithium lactate, lithium sulfate or sulfuric acid hydrogen Lithium etc. can be illustrated. These may be a single type of compound or a combination of a plurality of types of compounds. Among them, sodium acetate, potassium acetate, dipotassium carbonate, potassium bicarbonate, disodium carbonate, sodium bicarbonate, potassium sodium carbonate, lithium acetate, dilithium carbonate or lithium bicarbonate can be preferably used, preferably lithium. It is to use a salt, sodium salt or potassium salt, more preferably a sodium salt or potassium salt, particularly preferably a potassium salt. On the other hand, when viewed from the anion species side, among these, acetate, carbonate or hydroxide is preferred.

  The alkaline earth metal compound used in the present invention is not limited to the following, but specifically, calcium chloride, calcium formate, calcium succinate, calcium butyrate, calcium oxalate, calcium phosphate, calcium nitrate, Examples include calcium acetate, calcium lactate, magnesium chloride, magnesium formate, magnesium succinate, magnesium butyrate, magnesium oxalate, magnesium phosphate, magnesium nitrate, magnesium acetate, magnesium lactate, and magnesium sulfate. These may be a single type of compound or a combination of a plurality of types of compounds. Among these, it is preferable to use magnesium acetate or calcium acetate. Preferably, a calcium salt or a magnesium salt is used, and more preferably, a calcium salt is used. On the other hand, when viewed from the anion species side, among these, acetate, carbonate or hydroxide is preferred. Further, an alkali metal salt and an alkaline earth metal salt may be used in combination.

  Regarding the color adjusting agent, the polyester obtained by the production method of the present invention may contain 0.1 to 10 mass ppm of the color adjusting agent based on the total mass. The color adjusting agent represents an organic polyaromatic ring dye or pigment, and is preferably an anthraquinone dye, specifically, a blue color adjusting dye, a purple color adjusting dye, a red color dye. Examples thereof include color adjusting dyes and orange color adjusting dyes. These may be used singly or in combination of a plurality of types, but a blue color adjusting dye and a purple color adjusting dye may be used in a mass ratio of 90:10 to 40:60. preferable. Here, the blue color-modifying dye is generally indicated as “Blue” among commercially available color-adjusting dyes, and specifically, the maximum absorption in the visible light absorption spectrum in the solution. The wavelength is about 580 to 620 nm. Similarly, the purple color-modifying dye is the one described as “Violet” among commercially available color-adjusting dyes. Specifically, the maximum absorption wavelength in the visible light absorption spectrum in the solution is The thing in about 560-580 nm is shown. As these color adjusting pigments, oil-soluble dyes are particularly preferable. Specific examples of blue color adjusting pigments include C.I. I. Solvent Blue 11, C.I. I. Solvent Blue 25, C.I. I. Solvent Blue 35, C.I. I. Solvent Blue 36, C.I. I. Solvent Blue 45 (Polysynthren Blue), C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 78, C.I. I. Solvent Blue 83, C.I. I. Solvent Blue 87, C.I. I. Solvent Blue 94 and the like. Examples of purple color adjusting pigments include C.I. I. Solvent Violet 8, C.I. I. Solvent Violet 13, C.I. I. Solvent Violet 14, C.I. I. Solvent Violet 21, C.I. I. Solvent Violet 27, C.I. I. Solvent Violet 28, C.I. I. Solvent Violet 36 etc. are mentioned.

  Here, when the blue color adjusting dye and the purple color adjusting dye are used in combination, when the mass ratio of the blue color adjusting dye is larger than the mass ratio 90:10, the color a * value of the obtained polyester composition Is small and exhibits a green color, and when the mass ratio of the blue color adjusting dye is smaller than 40:60, the color a * value increases and a red color is exhibited, which is not preferable. The color adjusting dye is more preferably a blue color adjusting dye and a purple color adjusting dye used in a mass ratio of 80:20 to 50:50.

  These transesterification catalysts, polycondensation catalysts, stabilizers and additives can be supplied in the esterification step or transesterification reaction step as described above, or can be supplied to the polycondensation reaction step.

(Production method: solid phase polymerization reaction: preliminary crystallization step)
In the production method of the present invention, prior to solid phase polycondensation, the polyester obtained in the liquid phase polycondensation step is heated to a temperature higher than the crystallization temperature (Tc ₁ ) and lower than the melting point by 1 to You may perform the precrystallization process hold | maintained for 30 minutes. This preliminary crystallization step is carried out by subjecting the polyester to 1-30 in a dry state at a temperature lower than the temperature rising crystallization temperature (Tc ₁ ) to the melting point, preferably 10 ° C. higher than Tc ₁ and 40 ° C. lower than the melting point. For 5 minutes, preferably 5 to 20 minutes. For example, when the polyester is polyethylene terephthalate, it is specifically heated to a temperature of 160 to 200 ° C., preferably 165 to 190 ° C. for 1 to 30 minutes.

  The preliminary crystallization step is performed in air or in an inert gas atmosphere, but is preferably performed in an inert gas atmosphere, and more preferably performed in an inert gas atmosphere having an oxygen concentration of 20 ppm or less. . Examples of the inert gas include nitrogen gas, argon gas, and carbon dioxide gas.

  In this preliminary crystallization step, prior to the crystallization treatment at this temperature from the beginning, a preliminary treatment is performed at a temperature not higher than the sticking temperature of the polyester, for example, at a temperature of 100 ° C. or lower. It is preferable to carry out under reduced pressure to remove low-boiling components contained in the polyester. The preliminary treatment step is preferably performed in an inert gas atmosphere or under an inert gas flow. The above-mentioned inert gas can be used.

  The precrystallized polyester desirably has a crystallinity of 20 to 50%. In the precrystallization step, so-called polyester solid phase polycondensation reaction does not proceed, and the intrinsic viscosity of the precrystallized polyester is almost the same as the intrinsic viscosity of the polyester obtained in the liquid phase polycondensation step.

(Production method: solid phase polymerization reaction: solid phase polycondensation step (b))
In the production method of the present invention, the polyester obtained as described above or the precrystallized polyester may be subjected to solid phase polycondensation.
The solid phase polycondensation step comprises at least one stage, and the polycondensation temperature is usually 190 to 240 ° C, preferably 195 to 225 ° C. The solid phase polycondensation step (b) is performed in air or in the same inert gas atmosphere as described above or in vacuum, but is preferably performed in an inert gas atmosphere or in vacuum. When carried out in an inert gas atmosphere, the oxygen concentration is more preferably 50 ppm or less, preferably 20 ppm or less. The intrinsic viscosity of the polyester thus obtained is preferably 0.50 to 1.50 dL / g.

  The polyester formed product obtained by the above production method has a formaldehyde content of 1.0 ppm or less, preferably 0.5 ppm or less, and an acetaldehyde content of 10.0 ppm or less, preferably 7.5 ppm or less. More preferably, it is 6.0 ppm or less. Further, the content of other aldehydes such as naphthyl aldehyde, propionaldehyde, acrolein, benzaldehyde and the like can be reduced.

(Manufacturing method: subsequent step (c), for example, water treatment)
In the production method of the present invention, the polyester obtained by solid phase polycondensation as described above may be subjected to water treatment or steam treatment as necessary. The water treatment of the polyester obtained through the solid phase polycondensation step is performed by bringing the polyester into contact with water. The contact between the polyester and water is preferably carried out by immersing the polyester in water at room temperature to 150 ° C., preferably 70 to 110 ° C., for 1 minute to 20 hours, preferably 5 minutes to 10 hours. More specifically, it is immersed in water at 50 to 150 ° C. for 1 minute to 10 hours, preferably in water at 70 to 110 ° C. for 3 minutes to 5 hours, preferably in water at 70 to 110 ° C. for 3 minutes to 5 hours. Is done.

  When such a water treatment process is performed, mold contamination during injection molding is extremely reduced. This is because the polycondensation catalyst contained in the polyester is deactivated by bringing the polyester and water into contact with each other. Therefore, the decomposition reaction or the transesterification reaction hardly proceeds due to heating during molding. It is considered that the amount of oligomers such as a monomer is reduced and the amount of mold contamination is reduced. The water vapor treatment of polyester is performed by bringing polyester and water vapor into contact with each other. The polyester used here is preferably granular (pellet shape).

  The contact between the polyester and water vapor is achieved by bringing the polyester into contact with water vapor at room temperature to 230 ° C, preferably 70 to 150 ° C, more preferably 90 to 140 ° C for 1 minute to 20 hours, preferably 5 minutes to 10 hours. Preferably it is done. More specifically, it is brought into contact with water vapor at 50 to 230 ° C. for 1 minute to 10 hours, preferably with water vapor at 70 to 150 ° C. for 3 minutes to 5 hours, preferably with water vapor at 90 to 140 ° C. for 3 minutes to 5 hours. Is done. When such a steam treatment process is performed, mold contamination during injection molding is extremely reduced. This is because the polycondensation catalyst contained in the polyester is deactivated by bringing the polyester (b) into contact with water vapor, so that the decomposition reaction or transesterification reaction hardly proceeds by heating during molding. It is considered that the amount of oligomers such as cyclic trimer decreases and the amount of mold contamination decreases.

  The polyester obtained by water treatment or steam treatment as described above is dried. In the drying step, the polyester is heated at a temperature of 120 to 180 ° C, preferably 140 to 170 ° C for 2 to 24 hours, preferably 2 to 12 hours, more preferably 2 to 6 hours. The polyester is dried in air or in an inert gas atmosphere similar to the above, but is preferably performed in an inert gas atmosphere, and preferably in an inert gas atmosphere having an oxygen concentration of 20 ppm or less. More preferred. The polyester polycondensation reaction hardly proceeds in this drying step, and the intrinsic viscosity of the polyester obtained through the drying step is almost the same as the intrinsic viscosity of the polyester obtained in the solid phase polycondensation step.

  The polyester that has undergone the drying step is formed into various molded articles by an injection molding method. In injection molding, granular polyester contained in a hopper is usually supplied from a supply port to one end of a heating cylinder, melted in the heating cylinder, and melted from a nozzle provided on the side opposite to the supply port. A molded product is formed by injecting the polyester into a mold. At the time of injection molding, it is preferable to melt the polyester in the heating cylinder in an inert gas atmosphere. Examples of the inert gas include nitrogen gas, argon gas, and carbon dioxide gas, and nitrogen gas is particularly preferable. The oxygen concentration in the inert gas is 1% or less, preferably 0.1% or less, more preferably 0.01% or less. In the present invention, the inside of the hopper is also preferably an inert gas atmosphere, and the oxygen concentration in the inert gas is 1% or less, preferably 0.1% or less, more preferably 0.01% or less. Is preferred.

(About alkali metal aqueous solution treatment)
In the production method of the present invention, it may be necessary to contact the polyethylene naphthalate obtained by the above method with an aqueous solution of an alkali metal salt and / or an alkaline earth metal salt. The alkali metal salt used in the aqueous solution treatment in the production method of the present invention is not particularly limited as long as it is water-soluble, but specifically, potassium chloride, potassium alum, potassium formate, tricitrate Potassium, dipotassium hydrogen citrate, potassium dihydrogen citrate, potassium gluconate, potassium succinate, potassium butyrate, dipotassium oxalate, potassium hydrogen oxalate, potassium stearate, potassium phthalate, potassium hydrogen phthalate, metaphosphoric acid Potassium, potassium malate, tripotassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium nitrite, potassium benzoate, potassium hydrogen tartrate, potassium bioxalate, potassium biphthalate, potassium bitartrate, bisulfate Potassium, potassium nitrate, potassium acetate, potassium carbonate, Potassium sodium carbonate, potassium hydrogen carbonate, potassium lactate, potassium sulfate, potassium hydrogen sulfate, potassium hydroxide, sodium hydroxide, sodium chloride, sodium formate, trisodium citrate, disodium hydrogen citrate, sodium dihydrogen citrate, glucone Sodium phosphate, sodium succinate, sodium butyrate, disodium oxalate, sodium hydrogen oxalate, sodium stearate, sodium phthalate, sodium hydrogen phthalate, sodium metaphosphate, sodium malate, trisodium phosphate, dihydrogen phosphate Sodium, sodium dihydrogen phosphate, sodium nitrite, sodium benzoate, sodium hydrogen tartrate, sodium bioxalate, sodium biphthalate, sodium bitartrate, sodium bisulfate, sodium nitrate Sodium acetate, sodium carbonate, sodium bicarbonate, sodium lactate, sodium sulfate, sodium hydrogen sulfate, lithium hydroxide, lithium chloride, lithium formate, trilithium citrate, dilithium hydrogen citrate, lithium dihydrogen citrate, lithium gluconate , Lithium succinate, lithium butyrate, dilithium oxalate, lithium hydrogen oxalate, lithium stearate, lithium phthalate, lithium hydrogen phthalate, lithium metaphosphate, lithium malate, trilithium phosphate, dilithium hydrogen phosphate, Lithium dihydrogen phosphate, lithium nitrite, lithium benzoate, lithium hydrogen tartrate, lithium heavy oxalate, lithium biphthalate, lithium bitartrate, lithium bisulfate, lithium nitrate, lithium acetate, lithium carbonate, lithium hydrogen carbonate, lactic acid Re Examples thereof include lithium, lithium sulfate, and lithium hydrogen sulfate. These may be a single type of compound or a combination of a plurality of types of compounds. Among them, sodium acetate, potassium acetate, dipotassium carbonate, potassium bicarbonate, disodium carbonate, sodium bicarbonate, potassium sodium carbonate, lithium acetate, dilithium carbonate or lithium bicarbonate can be preferably used, preferably lithium. It is to use a salt, sodium salt or potassium salt, more preferably a sodium salt or potassium salt, particularly preferably a potassium salt. On the other hand, when viewed from the anion species side, among these, acetate, carbonate or hydroxide is preferred.

  The alkaline earth metal salt used in the aqueous solution treatment in the production method of the present invention is not particularly limited as long as it is water-soluble, but specifically, calcium chloride, calcium formate, calcium succinate, butyric acid Calcium, calcium oxalate, calcium phosphate, calcium nitrate, calcium acetate, calcium lactate, magnesium chloride, magnesium formate, magnesium succinate, magnesium butyrate, magnesium oxalate, magnesium phosphate, magnesium nitrate, magnesium acetate, magnesium lactate or magnesium sulfate, etc. Can be illustrated. These may be a single type of compound or a combination of a plurality of types of compounds. Among these, it is preferable to use magnesium acetate or calcium acetate. Preferably, a calcium salt or a magnesium salt is used, and more preferably, a calcium salt is used. On the other hand, when viewed from the anion species side, among these, acetate, carbonate or hydroxide is preferred. Further, an alkali metal salt and an alkaline earth metal salt may be used in combination.

(Manufacturing method: About manufacturing of molded products)
The polyester obtained by the production method of the present invention can produce various molded articles. For example, in order to mold a hollow molded body such as a bottle, first, a polyester subjected to a drying process is supplied to a molding machine such as an injection molding machine to mold a preform for the hollow molded body. The formaldehyde content of this preform for hollow molded bodies is usually 1.0 ppm or less, preferably 0.5 ppm or less, and the acetaldehyde content is usually 10.0 ppm or less, preferably 7.5 ppm or less, more preferably 6 ppm. 0.0 ppm. Next, this preform is inserted into a mold having a predetermined shape and stretch blow molded to form a hollow molded body. The formaldehyde content of this hollow molded body is usually 1.0 ppm or less, preferably 0.5 ppm or less, and the acetaldehyde content is usually 10.0 ppm or less, preferably 7.5 ppm or less, more preferably 6.0 ppm or less. It is. Of course, the molded body is not limited to a preform for a hollow molded body, and includes a film, a sheet, a fiber, a prism, a flat plate, a chip, and the like.

  The preform for hollow molded body produced by this method is suitable as a preform material for forming beverage filling containers because the formaldehyde content and acetaldehyde content in the polyester forming the hollow molded body preform are extremely low. Used for. The hollow molded body produced by the method of the present invention has a very low formaldehyde content and acetaldehyde content in the polyester forming the hollow molded body, and is less likely to change the taste of the contents. It is suitably used as (bottle).

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention does not receive limitation at all by this. In addition, each physical property value in an Example was calculated | required with the following method. In Examples and Comparative Examples, “parts” represents parts by weight.

Analysis method (1) Intrinsic viscosity (IV)
Intrinsic viscosity is measured by weighing a certain amount of the sample cut out from the chip, dissolved in o-chlorophenol at a concentration of 0.012 g / ml, and then once cooled, and the solution is heated to a temperature of 35 ° C. using an Ubbelohde viscometer. It calculated from the solution viscosity measured on condition.
(2) Col-L, b (hue)
The amorphous polymer was heat treated in a drier in a nitrogen atmosphere at 170 ° C. for 3 hours for crystallization, and then measured with a CM-7500 type color machine manufactured by Color Machine Co., Ltd. The crystallized polymer was measured with a CM-7500 type color machine manufactured by Color Machine.
(3) Diethylene glycol (DEG) content The diethylene glycol content was measured by decomposing a polyester sample with hydrazine and using gas chromatography manufactured by Agilent Technologies.

[Example 1]
In a mixture of 100 parts of dimethyl terephthalate and 56 parts of 1,2-ethylenediol, 3.0 millimol% of titanium atom of trimellitic acid as a titanium atom with respect to dimethyl terephthalate, stirrer, rectifying column and methanol fraction Charged in a stainless steel container capable of pressure reaction with a condenser, pressurized at 0.08 MPa, gradually raising the temperature from 140 ° C., while distilling methanol produced as a result of the reaction out of the system The transesterification reaction was performed. After 10 minutes from the completion of the distillation of methanol, 1.7 parts of terephthalic acid (2.0 mol% based on dimethyl terephthalate) was added 10 minutes later. When the internal temperature reaches 250 ° C., 5.0 mmol% of sodium acetate as sodium atom, 35 mmol% of germanium dioxide as germanium dioxide molecule and 10 mol of phosphoric acid as phosphorus atom with respect to dimethyl terephthalate. After adding 0.0 mmol% and stirring for 10 minutes, the reaction was terminated.
Subsequently, the obtained reaction product is transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port and a distillation device, and gradually heated from 210 ° C. to 280 ° C., and from a normal pressure to a high vacuum of 50 Pa. The polymerization reaction was carried out while reducing the pressure. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.51 dL / g. The molten polymer was extruded in the form of a strand from the bottom of the reactor into cooling water, and was cut into pellets using a strand cutter.

[Example 2]
In the transesterification reaction, Examples were changed except that the amount of terephthalic acid added 10 minutes after the completion of the distillation of methanol was changed to 3.4 parts (4.0 mol% based on dimethyl terephthalate). 1 was carried out.

[Example 3]
In the transesterification reaction, Example was changed except that the amount of terephthalic acid added 10 minutes after the completion of the distillation of methanol was changed to 8.6 parts (10.0 mol% with respect to dimethyl terephthalate). 1 was carried out.

[Reference Example] Production of bishydroxyethyl terephthalate (BHET) 3. In a mixture of 100 parts of dimethyl terephthalate and 56 parts of 1,2-ethylenediol, dimethyl terephthalate with titanium trimellitic acid as titanium atom; 0 mmol% was charged into a stainless steel container capable of pressure reaction equipped with a stirrer, rectification column and methanol distillation condenser, and pressurized to 0.08 MPa. As a result, the ester exchange reaction was carried out while distilling out the methanol produced out of the system. When the distillation of methanol was completed, the reaction product was taken out from the container, and used as BHET in Examples 4 to 6 below.

[Example 4]
131 parts of bishydroxyethyl terephthalate was charged into a stainless steel vessel equipped with a stirrer, rectifying column and methanol distillation condenser. When the internal temperature reached 250 ° C, 1.7 parts of terephthalic acid (into bishydroxyethyl terephthalate) 2.0 mol%) and 5.0 mmol% of sodium acetate as sodium atoms, 35.0 mmol% of germanium dioxide as germanium dioxide molecules, and 10 mol of orthophosphoric acid as phosphorus atoms relative to bishydroxyethyl terephthalate. After adding 0.0 mmol% and stirring for 10 minutes, the reaction was terminated.
Subsequently, the obtained reaction product is transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port and a distillation device, and gradually heated from 210 ° C. to 280 ° C., and from a normal pressure to a high vacuum of 50 Pa. The polymerization reaction was carried out while reducing the pressure. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.51 dL / g. The molten polymer was extruded in the form of a strand from the bottom of the reactor into cooling water, and was cut into pellets using a strand cutter.

[Example 5]
When the internal temperature reached 250 ° C., the same procedure as in Example 4 was performed except that the added terephthalic acid was changed to 3.4 parts (4.0 mol% based on bishydroxyethyl terephthalate).

[Example 6]
When the internal temperature reached 250 ° C., the same procedure as in Example 4 was performed except that the added terephthalic acid was changed to 8.6 parts (10.0 mol% based on bishydroxyethyl terephthalate).

[Example 7]
In a mixture of 100 parts of dimethyl terephthalate and 56 parts of 1,2-ethylenediol, 3.0 mmol% of titanium acetate as a titanium atom with respect to dimethyl terephthalate, stirrer, rectifying column and methanol distillation condenser The ester exchange reaction was performed while gradually raising the temperature from 140 ° C. and distilling methanol generated as a result of the reaction out of the system. The transesterification reaction was completed when a drop in the temperature at the top of the rectifying column was observed.
Subsequently, the obtained reaction product was transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port and a distillation apparatus, and 0.4 parts of terephthalic acid (1.0 mol relative to dimethyl terephthalate) was added thereto. %), 5.0 mmol% of potassium acetate as potassium atoms, 35.0 mmol% of germanium dioxide as germanium dioxide molecules, and 20.0 mmol% of orthophosphoric acid as phosphorus atoms were added to dimethyl terephthalate. Thereafter, the temperature was gradually raised from 210 ° C. to 280 ° C., and the polymerization reaction was performed while the pressure was reduced from normal pressure to a high vacuum of 50 Pa. After reaching a high vacuum state, the polymerization reaction was terminated in 60 minutes. The molten polymer was removed from the reactor and cut into pellets.

[Example 8]
The same operation as in Example 7 was carried out except that terephthalic acid added to the reaction product obtained by the transesterification reaction was changed to 8.6 parts (10.0 mol% with respect to dimethyl terephthalate).

[Example 9]
The same operation as in Example 7 was carried out except that 25.8 parts of terephthalic acid added to the reaction product obtained by the transesterification reaction was changed to 35.8 parts (30.0 mol% with respect to dimethyl terephthalate).

[Example 10]
The same procedure as in Example 7 was conducted, except that the polycarboxylic acid added to the reaction product obtained by the transesterification reaction was changed to 1.7 parts of isophthalic acid (2.0 mol% based on dimethyl terephthalate).

[Example 11]
The same operation as in Example 7 was carried out except that the polycarboxylic acid added to the reaction product obtained by the transesterification reaction was changed to 8.6 parts of isophthalic acid (10.0 mol% based on dimethyl terephthalate).

[Comparative Example 1]
A mixture of 100 parts of dimethyl terephthalate, 56 parts of 1,2-ethylenediol and 1.7 parts of terephthalic acid (2.0 mol% with respect to dimethyl terephthalate) is a trimerit to dimethyl terephthalate. Titanium oxide is used as a titanium atom, and 3.0 mmol% is charged into a stainless steel vessel capable of a pressure reaction provided with a stirrer, a rectifying column and a methanol distillation condenser, and pressurized to 0.08 MPa. While gradually raising the temperature, the ester exchange reaction was carried out while distilling out the methanol produced as a result of the reaction.
When the internal temperature reached 250 ° C., 5.0 mmol% sodium acetate as sodium atoms, 35 mmol% as germanium dioxide molecules and 35 mmol% as normal phosphoric acid as phosphorus atoms with respect to dimethyl terephthalate. After adding 0 mmol% and stirring for 10 minutes, the reaction was terminated.
Subsequently, the obtained reaction product is transferred to a reaction vessel equipped with a stirrer, a nitrogen inlet, a vacuum port and a distillation device, and gradually heated from 210 ° C. to 280 ° C., and from a normal pressure to a high vacuum of 50 Pa. The polymerization reaction was carried out while reducing the pressure. While tracing the melt viscosity of the reaction system, the polymerization reaction was terminated when the intrinsic viscosity reached 0.51 dL / g. The molten polymer was extruded in the form of a strand from the bottom of the reactor into cooling water, and was cut into pellets using a strand cutter.

[Example 12]
As a transesterification catalyst, instead of titanium trimellitic acid, titanium acetate is used in an amount of 3.0 mmol% as a titanium atom with respect to dimethyl terephthalate, and as a phosphorus compound, instead of normal phosphoric acid, triethylphosphonoacetate is used as a phosphorus atom. Was used as 10.0 mmol%. Further, in the transesterification reaction, the amount of terephthalic acid added 10 minutes after the completion of the distillation of methanol was changed to 3.4 parts (4.0 mol% with respect to dimethyl terephthalate), The same operation as in Example 1 was performed.

[Example 13]
In the transesterification reaction, the example was changed except that the amount of terephthalic acid added 10 minutes after the completion of the distillation of methanol was changed to 6.0 parts (7.0 mol% with respect to dimethyl terephthalate). This was carried out in the same manner as in No. 12.

[Example 14]
In the transesterification reaction, Example was changed except that the amount of terephthalic acid added after 10 minutes from the time when distillation of methanol was completed was changed to 8.6 parts (10.0 mol% with respect to dimethyl terephthalate). This was carried out in the same manner as in No. 12.

[Comparative Example 2]
The transesterification was carried out in the same manner as in Example 1 except that terephthalic acid was not added 10 minutes after the completion of the distillation of methanol. The results of Examples 1 to 14 and Comparative Examples 1 and 2 are shown in Table 1 below.

  According to the present invention, the content of the ether compound in the polyester can be suppressed without impairing the original properties of the polyester, and a polyester having a good hue can be provided. Fibers, films and sheets, resin molded products, foods It can be suitably used for packaging containers (bottles, containers, etc.) and non-food containers (pharmaceuticals, drinks, etc.).

Claims (10)

  In the polyester production method in which polycarboxylic acid A or an ester-forming derivative of polycarboxylic acid A and a polyol as a raw material are subjected to an esterification reaction or transesterification reaction, and then a polycondensation reaction is performed, after the esterification reaction is completed or transesterification A method for producing a polyester, characterized in that polycarboxylic acid B is added after the completion of the reaction.   The method for producing a polyester according to claim 1, wherein a germanium compound or a titanium compound is used as a polycondensation catalyst in the polycondensation reaction step, and further a phosphorus compound is used.   3. The method according to claim 1, further comprising a step of bringing the polycarboxylic acid B into a state of 5 kPa or less in the polycondensation reaction, and before adding the polycarboxylic acid B in the polycondensation reaction to a state of 1 kPa or less. The manufacturing method of polyester of description.   The method for producing a polyester according to any one of claims 1 to 3, wherein an ester-forming derivative of polycarboxylic acid A and a polyol are used as raw materials. The method for producing a polyester according to any one of claims 1 to 4, wherein the polyol is a compound represented by the following general formula (I).
HO— (CH ₂ ) n —OH 2 ≦ n ≦ 4 (I)   The method for producing a polyester according to any one of claims 1 to 5, wherein the ester-forming derivative of polycarboxylic acid A is an ester-forming derivative of terephthalic acid or naphthalenedicarboxylic acid.   The method for producing a polyester according to claim 6, wherein the ester-forming derivative of terephthalic acid or naphthalenedicarboxylic acid is bis (hydroxyethyl ester) terephthalate or bis (hydroxyethyl ester) naphthalenedicarboxylic acid.   The method for producing a polyester according to claim 6, wherein the ester-forming derivative of terephthalic acid or naphthalenedicarboxylic acid is terephthalic acid dimethyl ester or naphthalenedicarboxylic acid dimethyl ester.   The amount of the polycarboxylic acid B added in the polycondensation reaction is 1.0 to 50.0 mol% with respect to 1 mol of the polycarboxylic acid A as a raw material. The manufacturing method of polyester of description.   The method for producing a polyester according to any one of claims 1 to 9, wherein the polycarboxylic acid B added in the polycondensation reaction is the same kind of polycarboxylic acid as the polycarboxylic acid A.