JP4483433B2 - Polyester production method - Google Patents

Description

  The present invention relates to a method for producing a polyester, and more particularly to a method for producing a polyester having a color tone suitable for various uses such as a hollow molded container such as a bottle, a film, a sheet, and a fiber at a high reaction rate. .

  Polyesters such as polyethylene terephthalate are used in various fields because of their excellent properties such as mechanical strength and chemical stability, such as fibers for clothing and industrial materials, and various films for packaging and magnetic tape. It is widely used in various fields such as hollow molded products such as sheet, bottle container and engineering plastic molded products. Among them, it is excellent in gas barrier properties, hygiene, etc., is relatively inexpensive and lightweight, and is widely used as a food and beverage packaging container, and its application fields are expanding.

  In general, polyester is produced by a multi-step reaction using a dicarboxylic acid or an ester-forming derivative thereof and a diol as main raw materials. Usually, first, an esterification reaction in which a dicarboxylic acid such as terephthalic acid is directly reacted with a diol such as ethylene glycol, or an ester exchange reaction between an ester-forming derivative of a dicarboxylic acid such as dimethyl terephthalate and a diol such as ethylene glycol. To produce a relatively low molecular weight polyester precondensate comprising an ester such as bis (β-hydroxyethyl) terephthalate or a mixture of ester and oligoester. Next, this polyester precondensate is subjected to a polycondensation reaction in the presence of a catalyst for polycondensation reaction while separating by-produced alcohol and / or water to obtain a desired high molecular weight polyester. The obtained polyester is further subjected to solid phase polycondensation as necessary.

Conventionally, many catalysts for polycondensation reactions have been proposed, but in many commercial processes, antimony compounds or germanium compounds are used as catalysts for polycondensation reactions.
Antimony compounds, especially antimony trioxide (Sb ₂ O ₃ ), is a catalyst that is inexpensive and has excellent polycondensation reaction activity, but remains in the polyester produced using the Sb ₂ O ₃ catalyst. Tends to be relatively large particles and may remain as a foreign substance in the polyester. Furthermore, recently, a catalyst with higher safety is being demanded from the environmental viewpoint.

As a germanium compound used as a catalyst for polycondensation reaction, germanium dioxide (GeO ₂ ) or the like is known, and a higher quality polyester can be produced as compared with an antimony catalyst. However, germanium compounds are expensive, and there is an economic problem that the production cost of polyester is remarkably high.

  Research to provide a polycondensation reaction catalyst for polyester production in place of an antimony compound or a germanium compound has been repeated, and for example, an alkyl titanate catalyst such as tetrabutyl titanate has been proposed. (For example, see Japanese Patent Publication No. 49-11474 and Japanese Patent Publication No. 55-23136). However, the use of a titanium compound may cause significant coloration in the resulting polyester, and at present, further improvement in thermal stability during thermoforming is desired.

  On the other hand, a method of adding a phosphorus compound during a polycondensation reaction is widely known in order to suppress the coloring of the polyester and improve the thermal stability at the time of thermoforming. However, the addition of the phosphorus compound has a drawback that the polycondensation activity of the titanium compound catalyst is lowered, and there is a problem that the effect of the titanium compound catalyst is restricted.

In addition to the above, as a metal compound used as a catalyst for the polycondensation reaction, methods for producing polyesters using tungstates are disclosed in Japanese Patent Publication Nos. 44-19554 and 56-74123. However, when a tungsten compound is used as the catalyst for the polycondensation reaction, there is a coloring problem that the color tone of the produced polyester tends to become yellow, and the polymerization activity surface is not industrially sufficient.
Japanese Patent Publication No.49-11474 JP 55-23136 A Japanese Patent Publication No. 44-19554 JP-A-56-74123

  The object of the present invention is to solve the above-mentioned problems in the method for producing a polyester using a tungsten compound as a catalyst for polycondensation reaction in view of the above-mentioned prior art, that is, to solve the problems of the color tone and catalytic activity of the polyester. It is providing the manufacturing method of polyester which can manufacture the polyester which has it at high reaction rate.

An object of the present invention is to provide a method for producing a polyester having a good color tone at a high reaction rate, and the gist thereof is a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component and a diol having ethylene glycol as a main component. In a method for producing a polyester from a component through a polycondensation reaction, as a polycondensation reaction catalyst , at least one tungsten compound selected from the group consisting of tungstic acid, heteropolytungstic acid, isopolytungstic acid and salts thereof, and silicon There exists in the manufacturing method of polyester characterized by using a compound.

As a more preferred embodiment of the present invention method, silicic containing compound, it is tetraalkoxysilane and / or polyalkoxy siloxane compound, the proportion of the tungsten compound and a silicon compound in the catalyst, the molar ratio of the tungsten and silicon atoms (W: Si) is 1:10 to 10: 1, and in the polycondensation reaction, a phosphorus compound is used in combination.

  Since the polyester production method using a tungsten compound and a silicon compound as the polycondensation reaction catalyst of the present invention makes it possible to produce a polyester having good color tone at a high reaction rate, the production method of the present invention is industrially This is a very useful method.

  The present invention will be described in detail below, but the description of the constituent elements described below is a representative example of the embodiment of the present invention, and is not limited to these contents.

In the method for producing the polyester of the present invention, it is essential to use a tungsten compound and a silicon compound as the polycondensation reaction catalyst.
(Catalyst for polycondensation reaction)
The tungsten compound used as a polycondensation reaction catalyst in the polyester production method of the present invention will be specifically described.
The tungsten compound used as the catalyst for the polycondensation reaction is not particularly limited, and various compounds are used, such as tungstic acid, heteropolytungstic acid, isopolytungstic acid and salts thereof, tungsten oxide, and tungsten ethoxide. And compounds such as tungsten alkoxide. Among these compounds, at least one compound selected from the group consisting of tungstic acid, heteropolytungstic acid, isopolytungstic acid, and salts thereof is preferably used from the viewpoint of stability of the compound with respect to temperature during the polycondensation reaction. It is done.

As tungstic acid and tungstate, those represented by the following general formula (1) are usually used.
(Chemical formula 1)
(MI) _n (WO ₄ ) _m (1)
In the general formula (1), MI represents a cation, and n and m are in the range of 1 to 3 and take values that become neutral salts according to the valences of W and MI.
Examples of cations represented by MI include H ⁺ , NH ₄ ⁺ ; Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Cu ²⁺ , Ag ^+, etc. Cations; Group II metal cations such as Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ , Gd ³⁺ , etc .; La ³⁺ , Ce ³⁺ , Sm ³⁺ , Eu ³⁺ , Dy ³⁺ , Er ³⁺ , Yb ³⁺ Lanthanoids such as Lu ³⁺ , Group III metal cations such as Y ³⁺ , Al ³⁺ , and Tl ⁺ ; Group IV metal cations such as Ti ⁴⁺ , Zr ⁴⁺ , Sn ⁴⁺ , and Pb ²⁺ ; Groups such as Sb ³⁺ and Bi ³⁺ Group V metal cations; Group VII metal cations such as Mn ²⁺ ; Group VIII metal cations such as Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Ni ²⁺ and Ir ³⁺ . These cations are composed of one or a combination of a plurality of cations selected from the above.

Specific compounds of tungstic acid and its salts include tungstic acid (H ₂ WO ₄ ), sodium tungstate (Na ₂ WO ₄ ), potassium tungstate (K ₂ WO ₄ ), calcium tungstate (CaWO ₄ ), Ammonium tungstate ((NH ₄ ) ₂ WO ₄ ), aluminum tungstate (Al ₂ (WO ₄ ) ₃ ), barium tungstate (BaWO ₄ ), manganese tungstate (MnWO ₄ ), cobalt tungstate (CoWO ₄ ), Copper tungstate (CuWO ₄ ), iron tungstate (FeWO ₄ , Fe ₂ (WO ₄ ) ₃ ), lithium tungstate (Li ₂ WO ₄ ), zinc tungstate (ZnWO ₄ ), cerium tungstate (Ce ₂ (WO _{4) 3),} tungstic acid europium _(Eu 2 (W _{4) 3),} tungstic acid erbium _{(Er 2 (WO 4)} 3), tungsten lanthanum _{(La 2 (WO 4)} 3), tungstic acid thallium _(Tl 2 _WO 4), tungstic acid yttrium _(Y 2 (WO _{3 3} ), gadolinium tungstate (Gd ₂ (WO ₄ ) ₃ ), iridium tungstate (Ir ₂ (WO ₄ ) ₃ ), samarium tungstate (Sm ₂ (WO ₄ ) ₃ ), silver tungstate (Ag ₂ WO ₄ Ag ₂ WO ₄ ), zirconium tungstate (Zr (WO ₄ ) ₂ ), dysprosium tungstate (Dy ₂ (WO ₄ ) ₃ ), tin tungstate (Sn (WO ₄ ) ₂ ), antimony tungstate ( _{sb 2 (WO 4) 3)} , tungstic acid lutetium _(Lu 2 _(WO 4) ), Titanium tungstate _{(Ti (WO 4) 2)} , tungstic acid terbium _{(Yb 2 (WO 3) 3} ) and the like. Examples of the salt of the tungsten compound other than the structure of the general formula (1) include sodium tungsten citrate (Na ₃ W (C ₆ H ₅ O ₇ ) ₃ ). These tungsten compounds may be used as hydrates.

  Among these compounds described above, preferred are tungstic acid, sodium tungstate, calcium tungstate, ammonium tungstate, potassium tungstate and hydrates thereof, more preferably sodium tungstate, ammonium tungstate and These hydrates are mentioned.

  Tungstates exist as tungstate ions in solution, but they generate a series of isopolytungstate ions and heteropolytungstate ions with different degrees of polymerization due to conditions such as pH and the combination with other metal ions. The salts formed by these ions are also used as the compounds constituting the catalyst of the present invention.

No particular limitation is imposed on the iso poly tungstate ion, for ^{_{example, [W 7 O 24] 6-}} , [W 10 O 32] 4-, [W 6 O 19] 2-, [H 2 W 12 O 42] 10 _{^{-, [W 4 O 16]}} 8-, may be mentioned ions such as ^{_{6- [H 2 W 12 O 40}} ].
Examples of the compound that generates isopolytungstate ions include ordinary inorganic salts and organic salts, and these can be used as a catalyst for polycondensation reaction. Among them, preferred salt forms include ammonium metatungstate (NH ₄ [H ₂ W ₁₂ O ₄₀ ] · nH ₂ O, n is an integer), ammonium paratungstate (5 (NH ₄ ) ₂ O · 12WO ₃ ). Alternatively, ammonium salts such as 5 (NH ₄ ) ₂ O · 12WO ₃ · 5H ₂ O which are pentahydrates thereof, and alkali metal salts such as sodium polytungstate (3Na ₂ WO ₄ · 9WO ₃ · H ₂ O) Or an alkaline earth metal salt is mentioned. In particular, ammonium metatungstate can usually be stably stored and handled as a concentrated aqueous solution of about 50 wt% in terms of WO ₃ . Since ammonium paratungstate and its hydrate are usually poorly soluble in water and ethylene glycol, it is preferable to use them by dissolving them in an acidic substance that does not adversely affect polymerization such as phosphoric acid.

The compound comprising a heteropolytungstate ion used in the polycondensation reaction catalyst of the present invention includes 1 or 6 of an oxidation state of 6 ⁺ comprising an atomic group having a hetero atom encased by a MO ₆ octahedral cage structure. Any material formed by several tungsten atoms is included. Also included are deficient heteropolytungstic acids and salts thereof that lack a portion of the MO ₆ octahedron that is a component of the heteropoly acid.

  Specific examples of the compound include silicotungstic acid, phosphotungstic acid, cobalt tungstic acid, germanium tungstic acid, 1-deficient silicotungstic acid, 1-deficient phosphotungstic acid having Si, P, Ge, Co and the like as hetero atoms. More specifically, silicotungstic acid, phosphotungstic acid, sodium silicotungstate, potassium silicotungstate, ammonium silicotungstate, lithium silicotungstate, cesium silicotungstate, sodium phosphotungstate, phosphorous Examples thereof include potassium tungstate, ammonium phosphotungstate, lithium phosphotungstate, cesium phosphotungstate, and the like. Of these, silicotungstic acid, phosphotungstic acid, sodium silicotungstate, and sodium phosphotungstate are preferably used.

  In the polyester production method of the present invention, the amount of the tungsten compound used as the catalyst for the polycondensation reaction is usually 0.1 ppm, preferably 1 ppm, more preferably in terms of tungsten metal, based on the total weight of the polyester produced. Is 10 ppm, and the upper limit is usually 5000 ppm, preferably 150 ppm, more preferably 80 ppm. If the amount used is less than the lower limit, it is difficult to maintain sufficient catalyst activity, and if it is more than the upper limit, the thermal stability of the polyester may be lowered.

The polycondensation reaction catalyst used in the production method of the present invention can accelerate the polycondensation reaction rate by using a silicon compound together with the tungsten compound, and can carry out the polycondensation reaction at a high rate.
The silicon compound used is not particularly limited. For example, tetraalkoxysilane represented by the following general formula (2), polyalkoxysiloxane compound represented by the following general formula (3), silicon carboxylate such as silicon acetate, Examples include silanol compounds such as silanol, silanediol, and phenylsilanetriol.

(Chemical formula 2)
Si (OR ¹ ) ₄ (2)
(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and the alkyl group may be further substituted with a phenyl group or the like.)
(Chemical formula 3)
SiO _a (OR ² ) _b (OH) _c (3)
(In the formula, R ² represents an alkyl group having 1 to 4 carbon atoms. A = 0 to 1.3, b = 1.4 to 4.0, and c = 0.1, provided that 2a + b + c = 4. To fill.)

Among these, a tetraalkoxysilane represented by the general formula (2) and / or a polyalkoxysiloxane compound represented by the general formula (3) are preferable in terms of stability and dispersibility in the polycondensation reaction system.
Specific examples of the tetraalkoxysilane represented by the general formula (2) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and tetrabenzyloxysilane. Among these, tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane are preferable, and tetraethoxysilane is particularly preferable.

As the polyalkoxysiloxane compound represented by the general formula (3), an alkyl group represented by R ² in the general formula (3) is a methyl group, an ethyl group, a butyl group, an isobutyl group, an isopropyl group, or the like. Including at least one selected from these groups. As the alkyl group, a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable.
Among the polyalkoxysiloxane compounds, polymethoxysiloxane represented by the following general formula (4) is particularly preferable.

（但し、ｎ＝１〜100）
上記一般式（２）で示されるテトラアルコキシシラン及び一般式（３）で示されるポリアルコキシシロキサン化合物は単独で用いられてもよく、複数が混合して用いられてもよい。 General formula (4)

(However, n = 1 to 100)
The tetraalkoxysilane represented by the general formula (2) and the polyalkoxysiloxane compound represented by the general formula (3) may be used alone or in combination.

  The ratio of the tungsten compound and the silicon compound used as the polycondensation reaction catalyst in the production method of the present invention is such that the molar ratio of tungsten atom to silicon atom (W: Si) in the catalyst is usually 1:99 to 99: 1. Used to be The molar ratio of tungsten atoms to silicon atoms (W: Si) is preferably 1:20 to 20: 1, more preferably 1:10 to 10: 1. When there are few silicon atoms with respect to a tungsten atom, a polymerization rate may be slow, and the b value of the produced polyester tends to deteriorate. On the other hand, when there are too many silicon atoms, a silicon compound becomes an aggregate and may precipitate in polyester, and is unpreferable.

  In the production method of the present invention, other metal compounds may be used in combination with the tungsten compound and silicon compound used as the catalyst for the polycondensation reaction. As the other metal compound, a metal compound having at least one metal atom selected from titanium, germanium, antimony, and zinc is generally used. Among these, titanium alkoxide such as titanium tetrabutoxide, germanium oxide, antimony oxide, and zinc acetate are preferably used in combination. The amount of these metal compounds to be used varies depending on the kind of the compound, but is usually used in a range of 0.05 to 2.0 in terms of a molar ratio in terms of metal atom to the tungsten atom of the tungsten compound. In particular, when a titanium compound is used in combination, the molar ratio in terms of metal atom to the tungsten atom is preferably in the range of 0.05 to 0.5, particularly preferably in the range of 0.05 to 0.1.

In the production method of the present invention, a tungsten compound and a silicon compound are used as a catalyst for the polycondensation reaction, but a method in which a polycondensation reaction is further performed in combination with a phosphorus compound as a stabilizer is a thermal stability during thermoforming of the produced polyester. This is preferably performed from the viewpoint of improvement.
As a phosphorus compound, it can select from a conventionally well-known phosphorus compound as what brings the above physical property improvement effect, and can be used. Specifically, one or two selected from the group consisting of phosphoric acid or phosphate, phosphorous acid or phosphite, phosphate ester compound, phosphonic acid compound, phosphinic acid compound, phosphine oxide compound More than one type of compound can be used.

  Examples of phosphoric acid and phosphate include orthophosphoric acid, lithium phosphate, lithium dihydrogen phosphate, dilithium hydrogen phosphate, sodium phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate , Barium phosphate, zinc phosphate, strontium phosphate, strontium dihydrogen phosphate, distrontium hydrogen phosphate, zirconium phosphate, etc. Among these, normal phosphoric acid, sodium phosphate, sodium dihydrogen phosphate Potassium phosphate and potassium dihydrogen phosphate are preferably used.

  In addition, a salt of at least one metal selected from phosphorous acid, hypophosphorous acid, and alkali metals and alkaline earth metals thereof can be used, and specific salts include lithium phosphite, Examples thereof include sodium phosphite, potassium phosphite, strontium phosphite, zirconium phosphite, barium phosphite and zinc phosphite. Of these, phosphorous acid, hypophosphorous acid, sodium phosphite, sodium hypophosphite, and potassium phosphite are particularly preferably used.

  Examples of phosphate ester compounds include phosphate esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (triethylene glycol) phosphate, Acid phosphates such as ethyl diethyl phosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate, diethyl phosphate, tris Dodecyl phosphite, trisnonyl decyl phosphite, triphenyl phosphite, etc. Acid esters. Among them, tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid phosphate are preferable, and tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, ethyl acid phosphate, triethylene glycol acid acid are preferable. Phosphate is particularly preferred.

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

  The phosphorus compound used as the stabilizer is usually used in the range of 99: 1 to 1:99 in terms of the molar ratio of tungsten atom to phosphorus atom (W: P) with respect to the tungsten compound of the catalyst for polycondensation reaction, Preferably it is used at 50: 1 to 1:50, more preferably 20: 1 to 1:20, still more preferably 10: 1 to 1:10. If the phosphorus compound is used excessively with respect to the tungsten compound, the activity is lowered, and if it is too little, the effect of the original stabilizer is not recognized.

(Polycondensation reaction method)
The polyester production method of the present invention is not particularly limited except that a tungsten compound and a silicon compound are used as the catalyst for the polycondensation reaction. The polycondensation reaction in a general polyester production method is carried out in the presence of the above-mentioned catalyst. It can be carried out by polycondensation reaction between an acid component and a diol component.

  The dicarboxylic acid component used in the polyester production method of the present invention refers to dicarboxylic acid and / or an ester-forming derivative thereof, and the main component thereof is an aromatic dicarboxylic acid and / or an ester-forming derivative thereof. Here, the main component means that the aromatic dicarboxylic acid and / or ester-forming derivative thereof is 90 mol% or more with respect to the total dicarboxylic acid component, and 95% or more is more preferable.

  Specific examples of the aromatic dicarboxylic acid include terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4, Examples include 4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl ketone dicarboxylic acid, 4,4′-diphenoxyethane dicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and the like. Of these, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable, and terephthalic acid is more preferable.

  Examples of ester-forming derivatives include esters of lower alkyl groups having about 1 to 4 carbon atoms of the above aromatic dicarboxylic acids. Examples of components other than the main component in the dicarboxylic acid component include aliphatic dicarboxylic acids or ester-forming derivatives thereof. Specifically, for example, alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid and the like And aliphatic dicarboxylic acids and esters of lower alkyl groups having about 1 to 4 carbon atoms of these alicyclic dicarboxylic acids and aliphatic dicarboxylic acids. Among these, esters of lower alkyl groups of aromatic carboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, particularly methyl esters are preferred, and terephthalic acid methyl ester is most preferred.

  The diol component used in the method for producing the polyester of the present invention is not particularly limited as long as ethylene glycol is the main component. Here, the main component means that ethylene glycol is 80 mol% or more of the total diol component, and from the viewpoint of increasing the melting point of the produced polyester, 85 mol% or more is more preferable, and 90 mol% or more is preferable. Further preferred.

  Examples of diols other than the main component include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3- Aliphatic diols such as propanediol, diethylene glycol, polyethylene glycol, and polytetramethylene ether glycol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2 Cycloaliphatic diols such as 1,5-norbornane dimethylol; xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2 Aromatic diols such as bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and 2,2-bis (4′- Hydroxyphenyl) propane ethylene oxide adduct or propylene oxide adduct.

  In the polyester production method of the present invention, a monofunctional component and a polyfunctional component are further included in the range of several mol% with respect to the total dicarboxylic acid and / or its ester-forming derivative, without departing from the effects of the present invention. Also good. Specifically, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t- Monofunctional components such as butyl benzoic acid and benzoyl benzoic acid, trifunctional or more polyfunctional compounds such as tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol A functional component is mentioned.

As a method for producing the polyester of the present invention, a conventional method for producing polyester is basically applied except that a tungsten compound and a silicon compound are used as essential components as a catalyst for the polycondensation reaction. That is, as a representative example, first, a dicarboxylic acid component having the aromatic dicarboxylic acid or its ester-forming derivative as a main component and a diol component having ethylene glycol as a main component in an esterification reaction tank, usually 240 to Esterification reaction is carried out for about 1 to 10 hours under stirring at a temperature of about 280 ° C. and a pressure of about 0 to 4 × 10 ⁵ Pa relative to normal atmospheric pressure, or transesterification in the presence of a transesterification catalyst. After the reaction, the polyester low molecular weight product as the obtained esterification reaction product or transesterification reaction product is transferred to a polycondensation reaction tank, and is usually 250 to 290 ° C. in the presence of the polycondensation reaction catalyst. Melt polycondensation in about 1 to 20 hours with stirring under a reduced pressure of about 1333 to 13.3 Pa and finally a normal pressure gradually reduced from normal temperature to normal pressure. It is a manufacturing method which consists of making it. This production method can be performed either continuously or batchwise.

  The catalyst for the polycondensation reaction may be present at the time of the polycondensation reaction, and the addition method is not particularly limited, but specific addition methods of the catalyst include, for example, tungsten compound and silicon compound, ethylene glycol or other In the diol component, and the solution or slurry is the final stage esterification reaction tank in the multistage reaction apparatus, or the esterification reaction product in the transfer stage from the esterification reaction tank to the melt polycondensation process The method of adding to is mentioned. Further, when the silicon compound is a low molecular weight compound, it can be fed in a uniform liquid state.

The tungsten compound and the silicon compound are not necessarily mixed and added, but a method of mixing and adding is preferable in order to simplify the process. When the tungsten compound and the silicon compound are added separately, the order of addition is not limited, but the method of adding the tungsten compound after adding the silicon compound in advance and dispersing it promotes the dispersion of the tungsten compound. Therefore, it is preferable.
About the phosphorus compound as a stabilizer, the method of adding to the slurry preparation tank such as the raw material dicarboxylic acid component or the first stage esterification reaction tank is also preferable from the viewpoint of preventing the deterioration of the color tone of the oligomer. The method of adding is particularly preferable. That is, in the present invention, the order of addition of the tungsten compound, silicon compound, and phosphorus compound to the reaction system is preferably the phosphorus compound, then the silicon compound, and then the tungsten compound from the viewpoint of the color tone of the oligomer and the dispersion of the tungsten compound. .

  Usually, the polyester obtained by the melt polycondensation reaction is extracted in the form of a strand from an extraction port provided at the bottom of the polycondensation reaction tank, and is pelletized by being cut with a cutter or the like while cooling with water or with water. And a granular material such as a chip. The intrinsic viscosity of the obtained granular material is usually 0.4 dl / g or more and 1.5 dl / g or less.

The polyester thus obtained may be subjected to solid phase polycondensation in order to increase the degree of polymerization and further reduce the reaction by-products such as cyclic trimer and acetaldehyde, if desired.
In general, the solid phase polycondensation is performed at a temperature at which the polyester used for the solid phase polycondensation reaction does not melt, preferably 190 to 250 ° C., particularly preferably 195 to 240 ° C., nitrogen, argon, carbon dioxide, etc. When the reaction is performed in an inert gas atmosphere, the absolute pressure is 0.1 MPa or less, preferably 0.02 MPa or less, or when the reaction is performed under a reduced pressure atmosphere, the absolute pressure is 13 Pa to 6665 Pa. Preferably, it is performed at an absolute pressure of 65 Pa to 1333 Pa.

  The temperature, pressure, reaction time, inert gas flow rate, etc. of the solid phase polycondensation are appropriately selected so that the polyester product has the desired physical properties, but the polyester obtained by the production method of the present invention is solid phase weighted. When condensed, the tungsten compound and silicon compound used as the polycondensation reaction catalyst have high activity even in the solid-phase polycondensation reaction. Therefore, the conventional production does not use the tungsten compound and silicon compound as the polycondensation reaction catalyst. There is an advantage that the reaction time can be shortened as compared with polyester by the method.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.
In addition, the physical property etc. of the polyester in this invention were measured with the following method.

(Measurement of intrinsic viscosity)
A sample of 0.5 g of polyester is required for 30 minutes at 110 ° C. with a phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1) mixed solvent at a concentration (c) of 1.0 g / dl. To dissolve. The relative viscosity (ηrel) of this solution is measured at 30 ° C. using an Ubbelohde capillary viscosity tube. A ratio (ηsp / c) with respect to the concentration (c) is obtained for the specific viscosity (ηsp) obtained from the relative viscosity. Similarly, the ratio (ηsp / c) with respect to the concentration (c) of each solution having the concentration (c) of 0.5 g / dl, 0.2 g / dl, and 0.1 g / dl was determined, and from these values, the concentration ( The ratio (ηsp / c) when c) was extrapolated to 0 was determined as the intrinsic viscosity [η] (dl / g).

(Color tone)
Lab described in Reference Example 1 of JIS Z8730 by filling the polyester chip after melt polycondensation into a powder colorimetric cell and using a colorimetric color difference meter ZE-2000 (Nippon Denshoku Industries Co., Ltd.). The color b value by the color coordinate of Hunter's color difference formula in the display system was obtained.

(Melt polycondensation rate)
The polycondensation rate ks is determined by the following formula (5).
(Equation 1)
ks = ln (Mn ′ / Mn / T) × 10 ² (5)
Mn ′ is the number average molecular weight of the polymer calculated from the intrinsic viscosity [η] (dl / g) after melt polycondensation, and Mn is the number average molecular weight of the polymer calculated from the intrinsic viscosity before melt polycondensation. .
T is the melt polycondensation time (min) after the start of decompression.
In addition, molecular weight Mn and Mn 'are calculated | required by following formula (6).
(Equation 2)
Molecular weight (Mn or Mn ′) = (Intrinsic viscosity [η] /0.00021) ^{(1 / 0.82)} (6)

[Example 1]
A polyester oligomer (number average degree of polymerization = 7, esterification rate = 5) is obtained by conducting an esterification reaction in a continuous reaction tank at a molar ratio of terephthalic acid and ethylene glycol of about 265 ° C. for about 5 hours without catalyst. About 91%). 104 g of this polyester oligomer was charged into a polycondensation reaction tank, the inside of the reaction tank was purged with nitrogen, and then the oligomer was melted in an oil bath at 270 ° C. Next, while stirring the oligomer with a three-one motor with a torque meter at a speed of 150 rpm, sodium tungstate dihydrate (Na ₂ WO ₄ .2H ₂ O) and a polymethoxysiloxane compound (trade name: MKC) are used as catalysts. Silicate MS56S: manufactured by Mitsubishi Chemical Co., Ltd., 59.7% by weight as SiO ₂ content) is 100 ppm by weight as each metal atom (W, Si) with respect to the polyester resin from which tungsten atoms and silica atoms are obtained. And mixed with 3 ml of ethylene glycol.

  The pressure reduction started 5 minutes after the addition of the catalyst, and the pressure was reduced to an absolute pressure of 133 Pa in 20 minutes. Stirring was stopped 55 minutes after starting the pressure reduction, and the system was returned to normal pressure with nitrogen to complete the polycondensation reaction. Next, the polyester product was extracted in the form of a strand from the outlet at the bottom of the reaction tank, cooled with water, and then cut into chips with a cutter. Table 1 shows the results of measuring the intrinsic viscosity and the color b value of the obtained polyester chip.

[Example 2]
In Example 1, when adding the catalyst, orthophosphoric acid (H ₃ PO ₄ ) was added so as to be 22 ppm by weight with respect to the polyester from which phosphorus atoms were obtained, and the reaction was completed 77 minutes after the start of decompression. Produced polyester in the same manner as in Example 1. Table 1 shows the measurement results of the intrinsic viscosity and the color b value of the obtained polyester chip.

[Comparative Example 1]
In Example 1, a polyester was produced in the same manner as in Example 1 except that the polymethoxysiloxane compound (MKC silicate MS56S) was not used and the reaction was terminated after 70 minutes from the start of pressure reduction. Table 1 shows the measurement results of the intrinsic viscosity and the color b value of the obtained polyester chip.

[Comparative Example 2]
In Example 2, a polyester was produced in the same manner as in Example 2 except that the polymethoxysiloxane compound (MKC silicate MS56S) was not used and the reaction was terminated 90 minutes after the start of pressure reduction. Table 1 shows the measurement results of intrinsic viscosity and color b value of the obtained polyester chip.

In Comparative Example 1 in which no silicon compound was used with respect to Example 1, both the polymerization rate and the b value deteriorated. Furthermore, also in the comparative example 2 which did not use a silicon compound with respect to Example 2 using a phosphorus compound, it resulted in that a polymerization rate and b value deteriorated.
These results show that a polyester having good color tone can be obtained at a high polymerization rate by combining a tungsten compound and a silicon compound.

Claims (4)

In a method for producing a polyester through a polycondensation reaction from a dicarboxylic acid component containing aromatic dicarboxylic acid as a main component and a diol component containing ethylene glycol as a main component , tungstic acid, heteropolytungstic acid, A method for producing a polyester, comprising using at least one tungsten compound and silicon compound selected from the group consisting of polytungstic acid and salts thereof . The method for producing a polyester according to claim 1 , wherein the silicon compound is a tetraalkoxysilane and / or a polyalkoxysiloxane compound. 3. The polyester according to claim 1, wherein a ratio of tungsten compound to silicon compound in the catalyst is 1:10 to 10: 1 in terms of a molar ratio of tungsten atom to silicon atom (W: Si). Manufacturing method. The method for producing a polyester according to any one of claims 1 to 3 , wherein a phosphorus compound is used in combination in the polycondensation reaction.