JP2006002161A - Polyester resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin using, as the catalyst element, titanium excellent in environmental safety, excellent in color tone, generating little amount of byproducts such as acetaldehyde and cyclic trimers and suitable for food containers. <P>SOLUTION: The polyester resin is obtained by polymerizing a dicarboxylic acid component composed mainly of an aromatic dicarboxylic acid or its ester-forming derivative and a diol component composed mainly of ethylene glycol in the presence of a catalyst containing Ti compound and has following physical properties. Wherein, the physical properties are: 0.002-1.0 mol/t Ti content, ≥0.70 dl/g intrinsic viscosity, ≤4 color tone b value, and ≤5.0 ppm acetaldehyde content. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester resin such as polyethylene terephthalate widely used in various packaging containers, films, fibers and the like. More specifically, the present invention relates to a polyester resin that uses titanium, which is excellent in environmental safety and inexpensive, as a polycondensation catalyst element, exhibits excellent color tone, has few by-products, and can be suitably used for molding bottles and the like.

  Polyester resins such as polyethylene terephthalate are excellent in mechanical strength, chemical stability, gas barrier properties, hygiene, etc., and are relatively inexpensive and lightweight, so they are widely used as various packaging containers, films, fibers, etc. Yes. Such a polyester resin has been conventionally produced mainly using an antimony compound as a polycondensation catalyst.

  However, when a polyester resin polymerized using an antimony compound as a polycondensation catalyst is used, for example, as a food and drink container, the antimony remaining in the resin is eluted from the container at a high temperature and the contents of the food and drink There is concern about a slight shift to the product, and environmental pollution caused by the use of heavy metal antimony, antimony is not used at all or is extremely low, or other safer catalyst It was desired to use metal.

  A polyester resin polymerized by using a germanium compound instead of the antimony catalyst is also known. However, germanium compounds have very small reserves and are therefore very expensive, and a catalyst that can be used as an alternative has been desired. Various proposals have been made on polyester resins polymerized using inexpensive and safe titanium compounds. Titanium catalysts are more active than antimony catalysts and germanium catalysts, and can be used in small amounts. Furthermore, there are no health and safety concerns like antimony catalysts, and they are cheaper than germanium catalysts. Polyester resin was an industrially valuable study subject. However, the polyester resin polymerized using a titanium compound has a drawback that the amount of acetaldehyde, which is a coloring or by-product, is large.

  On the other hand, Japanese Patent Application Laid-Open No. 8-73581 proposes a polyester which is produced using a limited amount of a complexing agent and a titanium compound and does not contain antimony and has excellent achromatic transparency. However, according to the studies by the present inventors, the polyester resin obtained by the method described in the above-mentioned published patent has a large amount of by-product acetaldehyde and cyclic trimer, and is molded for food containers such as bottles. In some cases, the resulting bottle affects the flavor of the contents, and there is a problem that the mold is severely contaminated during the molding of the bottle. Further, in this method, cobalt (blue tint), which is a heavy metal, is used to improve the color tone. Agent) is not preferable from the viewpoint of environmental safety.

  The present invention was made in view of the above problems, uses titanium having excellent environmental safety as a polycondensation catalyst element, exhibits excellent color tone, and has few by-products such as acetaldehyde and cyclic trimer, Therefore, when it shape | molds for food containers, such as a bottle, it aims at providing the polyester resin with which the bottle obtained does not affect the flavor of the content and the color tone of a bottle is favorable.

  As a result of various studies on polyester resins produced using a titanium compound as a polycondensation catalyst, the present inventors have succeeded in obtaining a polyester resin that can achieve the above-mentioned object. That is, the gist of the present invention is obtained by polymerizing a dicarboxylic acid component containing an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component and a diol component containing ethylene glycol as a main component in the presence of a titanium compound. The polyester resin is characterized in that the content of titanium atom (Ti) per ton of the polyester resin is 0.002 to 1.0 mol and has the following physical properties.

[Equation 4]
Intrinsic viscosity ≧ 0.70 dl / g
Color tone b value ≦ 4
Acetaldehyde content ≦ 5.0 (ppm)

  The polyester resin of the present invention is obtained by using titanium, which is excellent in environmental safety and inexpensive, as a polycondensation catalyst element, and is obtained by selecting catalyst components and polycondensation conditions, and exhibits excellent color tone, and There are few by-products such as acetaldehyde and cyclic trimer, so when molded for food containers such as bottles, the resulting bottles do not affect the flavor of the contents, and the color tone of the bottles is also good. Has the advantage.

The present invention is described in detail below.
In the polyester resin of the present invention, a slurry of a dicarboxylic acid component and a diol component of an aromatic dicarboxylic acid or an ester-forming derivative thereof is prepared according to a conventionally known method, and a low molecular weight polyester is obtained by esterification or transesterification. This can be produced by polycondensation by melt polymerization in the presence of a titanium compound-containing catalyst and, if necessary, further solid-phase polymerization. The polyester resin of the present invention contains a titanium compound which is a polymerization catalyst and a metal component derived from a co-catalyst or a promoter component used as necessary, and the amount of addition, addition method and polymerization reaction of these metal components. It has a predetermined physical property value by controlling the conditions.

1. Constituent Component of Polyester Resin The polyester resin of the present invention is produced from a dicarboxylic acid component having an aromatic dicarboxylic acid or an ester-forming derivative thereof as a main component and a diol component having ethylene glycol as a main component.

  In the present invention, specific examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, phthalic acid, isophthalic acid, dibromoisophthalic acid, sodium sulfoisophthalic acid, phenylenedioxydicarboxylic acid, 4 , 4'-diphenyldicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 4,4'-diphenylketone dicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2, Examples include 6-naphthalenedicarboxylic acid, alkyl esters having about 1 to 4 carbon atoms of these aromatic dicarboxylic acids such as dimethyl terephthalate and dimethyl ester of 2,6-naphthalenedicarboxylic acid, and halides.

  Examples of dicarboxylic acid components other than the aromatic dicarboxylic acid and its ester-forming derivatives include, for example, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and succinic acid, glutaric acid, and adipic acid. , Piperic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid, dodecadicarboxylic acid and other aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids and aliphatic dicarboxylic acids having 1 to 4 carbon atoms Degree alkyl esters, and halides.

  Examples of diol components other than ethylene glycol include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1 , 3-propanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene ether glycol and other aliphatic diols, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1, Cycloaliphatic diols such as 4-cyclohexane dimethylol and 2,5-norbornane dimethylol, xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2- (4'-hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, 4,4'-bis (2-hydroxyethoxy) diphenylsulfone And 2,2-bis (4′-hydroxyphenyl) propane ethylene oxide adduct or propylene oxide adduct, and the like.

  Furthermore, for example, hydroxycarboxylic acids and alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and stearyl alcohol, docosanol, octacosanol, benzyl alcohol, stearic acid, behenic acid, melidine Monofunctional components such as acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol , Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] trifunctional or higher polyfunctional components such as methane, etc. It may be used as a component.

  Among these, the present invention is a carboxylic acid component containing terephthalic acid or 2,6-naphthalenedicarboxylic acid as a main component, in particular, a carboxylic acid component containing terephthalic acid as a main component and a diol component containing ethylene glycol as a main component. It is particularly preferably applied to polyester produced from the above, and the effects of the present invention are exhibited.

  In the polyester resin of the present invention, the aromatic dicarboxylic acid or an ester-forming derivative thereof is 50 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, particularly preferably 99 mol% of the dicarboxylic acid component. Esterification of a dicarboxylic acid component occupying the above and ethylene glycol with a diol component occupying 50 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, particularly preferably 97 mol% or more of the diol component It is produced by polycondensation through a reaction or transesterification reaction. The diethylene glycol by-produced in the reaction system may be copolymerized, and the content of diethylene glycol including the amount added from outside the system as a copolymerization component is 4 mol% or less, more preferably 3 mol% or less. It is. If the amount of diethylene glycol is large, the amount of acetaldehyde in the resin increases, and the heat resistance when a molded body such as a stretched bottle is formed decreases.

2. Content of Titanium in Polymerization Catalyst and Polyester Resin The polyester resin of the present invention is polymerized in the presence of a titanium compound catalyst and contains titanium derived from the catalyst.

  Titanium compounds used as catalysts include tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, tetraphenyl titanate, tetracyclohexyl titanate, tetrabenzyl titanate, tetra-n -Butyl titanate tetramer, titanium acetate, titanium oxalate, potassium oxalate titanate, sodium oxalate titanate, potassium titanate, sodium titanate, titanate-aluminum hydroxide mixture, titanium chloride, titanium chloride-aluminum chloride mixture, Examples include titanium oxalate, titanium fluoride, potassium hexafluorotitanate, manganese hexafluorotitanate, ammonium hexafluorotitanate, and titanium acetylacetonate. These are not particularly limited, but tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, oxalate titanate, and potassium oxalate titanate are preferable.

The amount of the titanium compound used is such that the content of titanium atoms (Ti) per ton of the obtained polyester resin is 0.002 to 1.0 mol.
When the amount of titanium atom per tonne of polyester resin is less than 0.002 mol, a sufficient polymerization rate cannot be obtained, and when it exceeds 1.0 mol, the color tone and acetaldehyde of the obtained polyester resin are not obtained. Since it adversely affects the amount, it is not preferable. A preferable amount is 0.002 to 0.5 mol, more preferably 0.002 to 0.2 mol, and still more preferably 0.002 to 0.06 mol of titanium atom per tonne of polyester resin. The amount is particularly preferably 0.002 to 0.04 mol.

3. Physical properties of polyester resin The polyester resin of the present invention is a resin having the following properties.

[Equation 5]
Intrinsic viscosity ≧ 0.70 (dl / g)
Hunter color coordinate b value ≦ 4
Acetaldehyde content ≦ 5.0 (ppm)

  The intrinsic viscosity (IV) of the polyester resin of the present invention is 0.70 dl / g or more, preferably 0.70 dl / g or more and 1.5 dl / g or less, more preferably 0.70 dl / g or more and 0.90 dl / g. g or less, more preferably 0.70 dl / g or more and 0.80 dl / g or less. The intrinsic viscosity in this case is that the polyester resin is freeze-ground and then dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1). , 0.2, 0.5, 1 g / dl, and the viscosity of each solution was measured at a temperature of 30 ° C. with an Ubbelohde capillary viscosity tube, and the value obtained by extrapolating the viscosity at a concentration of 0 g / dl was obtained. It is.

  If the intrinsic viscosity is small, the strength of a molded article such as a bottle is insufficient. If the intrinsic viscosity is high, it takes time to melt the resin during injection molding of preforms of molded products such as bottles. At that time, the amount of by-products such as acetaldehyde and cyclic trimers increases, and the preforms When stretched and blown into a bottle, a large stretching stress is applied, and molding productivity is deteriorated.

  The intrinsic viscosity can be adjusted to a desired viscosity by adjusting conditions such as temperature and time of melt polymerization at the time of polyester production and, if necessary, subsequent crystallization and solid-phase polymerization, depending on applications. For example, the intrinsic viscosity is 0.10 dl / g or more and 0.70 dl / g or less by melt polymerization, more preferably 0.30 dl / d or more and 0.70 or less, and further preferably 0.50 dl / g or more and 0.65 dl / g or less. Further, when the intrinsic viscosity is 0.70 dl / g or more by crystallization / solid phase polymerization, a preferable polyester resin can be obtained in terms of color tone, polymerization rate, acetaldehyde and by-product amounts of cyclic low-polymer.

The color tone of the polyester resin of the present invention is JIS
The Hunter color coordinate b value in the Lab coordinate system described in Reference 1 of Z8730 is 4 or less, preferably −10 to 3, more preferably −5 to 2, more preferably −3 to 1, most preferably. Is -2 to 0. When the b value is 4 or less, the color tone is good when the molded product is obtained. However, when the b value exceeds 4, the yellowness of the molded product tends to be too strong, and less than −10. When it is, there exists a tendency for the blueness at the time of setting it as a molded article to be too strong.

  The b value can be adjusted by the polymerization conditions and the type, amount and order of the catalyst system to be added. Although it can be adjusted by adding a coloring material (dye) or the like to the polymerization system, it is preferable not to add the coloring material (dye) because it contaminates the polymerization equipment, molding equipment and the like. Further, although a small amount of Co can be added as a metal for bluing, Co is a heavy metal, and even when used in the same manner as Sb, it is preferably an extremely low amount, more preferably not added at all.

  The acetaldehyde content of the polyester resin of the present invention is 5.0 ppm or less, preferably 3.0 ppm, more preferably 2.0 ppm or less. When the acetaldehyde content exceeds 5.0 ppm, when the molded product is formed, the molded product has a great influence on the flavor of the contents. Ppm is based on weight. Furthermore, the cyclic trimer content of the polyester resin of the present invention is preferably 0.50% by weight or less. More preferably, it is 0.40 weight% or less. If the content of the cyclic trimer exceeds 0.50% by weight, the cyclic trimer adheres to the mold when the molded product is manufactured, contaminates the mold, and harms the appearance of the molded product. Product productivity tends to deteriorate due to mold cleaning.

The physical properties of the polyester resin can be adjusted by using a polymerization catalyst obtained by adding an appropriate cocatalyst component or promoter component to a titanium compound.
Specifically, a suitable amount of at least one compound selected from (1) a phosphorus compound and (2) a group Ia element compound excluding hydrogen, a group IIa element compound and a manganese compound is used in combination with a titanium compound as a polymerization catalyst. Is preferred.

  (1) Phosphorous compounds include phosphorous acid and hypophosphorous acid, and esters thereof (for example, diethyl phosphite, triphenyl phosphite, trisdodecyl phosphite and trisnonyl decyl phosphite), and And trivalent phosphorus compounds such as metal salts such as lithium, sodium and potassium. In addition, orthophosphoric acid and polyphosphoric acid, and esters thereof (for example, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (triethylene glycol) phosphate And pentavalent acid phosphates such as ethyl diethyl phosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate and triethylene glycol acid phosphate The following phosphorus compounds are mentioned.

  Of these, phosphorous acid, orthophosphoric acid, ethyl acid phosphate, tris (triethylene glycol) phosphate, triethylene glycol acid phosphate and ethyl diethyl phosphonoacetate are preferred, and the viewpoint of suppressing foreign matter formation and color tone in the polymerization system From the above, ethyl acid phosphate, tris (triethylene glycol) phosphate, triethylene glycol acid phosphate and ethyl diethylphosphonoacetate are particularly preferred.

  The amount of the phosphorus compound used is such an amount that the content of phosphorus atoms is 0.02 to 4 mol, preferably 0.02 to 2 mol per ton of the obtained polyester resin. Depending on the amount of the phosphorus compound used, the color tone and polymerization rate of the resulting polyester resin, and adjustment of by-products such as acetaldehyde and cyclic trimer can be made.

  (2) Group Ia element compound excluding hydrogen, group IIa element compound, and manganese compound are raw material diol components such as ethylene glycol, alcohol and water soluble compounds, for example, lithium, sodium, potassium Oxides such as magnesium and calcium, hydroxides, alkoxides, acetates, carbonates, oxalates, halides, etc., specifically, for example, lithium acetate, sodium acetate, potassium acetate, magnesium oxide, water Examples thereof include magnesium oxide, magnesium alkoxide, magnesium acetate, magnesium carbonate, calcium oxide, calcium hydroxide, calcium acetate, calcium carbonate, manganese oxide, manganese hydroxide, and manganese acetate. Among these, a magnesium compound and a manganese compound are preferable, and a magnesium compound is particularly preferable.

  The amount of the Group Ia element compound excluding hydrogen, the Group IIa element compound, and the manganese compound is such that the content of at least one atom selected from the group consisting of these atoms per ton of the obtained polyester resin is 0.04. An amount of ˜5 mol is preferable, and an amount of 0.04 to 3 mol is more preferable. In particular, a preferable amount in the case of using a magnesium compound as the metal compound is 0.1 to 3 mol, more preferably 0.2 to 2 mol, particularly preferably 0. 3 to 1 mole. If it is less than the above range, the polymerizability is lowered, and if it exceeds the above range, the color tone tends to deteriorate.

  The amount of the titanium compound and these metal compounds used in the polymerization catalyst can not only control the polymerization rate during the polymerization reaction but also adjust the color tone of the resulting polyester resin, the amount of acetaldehyde and cyclic trimer by-products. .

  In particular, the titanium atom content Ti (mole) per ton of the polyester resin of the present invention, the phosphorus atom content P (mole), and a group selected from the group consisting of group Ia atoms, group IIa atoms and manganese atoms excluding hydrogen It is preferable that the content M (mol) of at least one kind of atoms satisfy the relationship of the following formula.

[Equation 6]
P / Ti ≧ 1
1 ≧ P / (Ti + M) ≧ 0.1
1 ≧ P / M> 0
A more preferable value of P / Ti is 5 to 50, and further preferably 15 to 30. When the value of P / Ti is less than 1, the resulting polyester resin tends to be yellowish and have a poor color tone.

A more preferable value of P / (Ti + M) is 0.2 to 1, more preferably 0.4 to 1. When the value of P / (Ti + M) is less than 0.1, the resulting polyester resin is yellowish and the color tone is deteriorated. On the other hand, when it exceeds 1, the polymerizability tends to be deteriorated.
The value of P / M is more preferably 0.2 to 1, and still more preferably 0.4 to 1. When the value of P / M exceeds 1, the polymerizability tends to deteriorate.

  Furthermore, the content Ti (mol) of titanium atoms per ton of the polyester resin of the present invention and the content M (moles) of at least one atom selected from the group consisting of group Ia atoms, group IIa atoms and manganese atoms excluding hydrogen ) Ratio M / Ti is preferably 2.5 to 250, more preferably 15 to 150, and even more preferably 25 to 50.

When M / Ti is smaller than this range, the polymerizability is lowered, and when it is larger than this range, the color tone tends to deteriorate.
The reason why it is preferable that the catalyst composition of the polyester resin of the present invention satisfies the above formula is not clear, but is presumed as follows. That is, by increasing P / Ti, side reactions such as color tone of the Ti catalyst and acetaldehyde generation are suppressed, but this also reduces the polymerization activity of the Ti catalyst. In contrast, by adding a very small amount of M, the polymerization activity is compensated by the cocatalyst effect, and sufficient polymerization activity can be obtained while suppressing side reactions such as the color tone of the Ti catalyst and acetaldehyde formation. Inferred to be possible. In that case, as a required addition amount of M, 0.04 to 5 mol per ton of polyester resin is sufficient as described above, and the required amount when M is used alone as a main catalyst is usually larger than 5 mol. From the above, it can be seen that the promoter effect of M is characteristically exhibited in combination with Ti. In that case, it is presumed that P / M or P / (Ti + M) is preferably in a relatively small range as described above in order to avoid deactivation of M or Ti + M by P.

  Further, in the polymerization of the polyester resin of the present invention, in addition to the metal compounds of the above (1) and (2), (3) a small amount of germanium compound may be used in combination. The amount, the amount of cyclic trimer and the like can be made preferable. The amount of germanium is preferably 0 to 0.4 mol, more preferably 0 to 0.3 mol, still more preferably 0 to 0.2 mol, and most preferably 0, with respect to 1 ton of polyester resin. It is the quantity which becomes -0.1 mol. A large amount of the germanium compound used increases the production cost of the resin as described above.

Specific examples of the germanium compound include germanium dioxide, germanium tetroxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, germanium tetra-n-butoxide, and the like. Germanium is preferred.
In addition to the above, a component derived from a compound usually used when producing a polyester resin may be contained. Specific examples include zirconium, hafnium, chromium, molybdenum, tungsten, iron, nickel, gold, silver, copper, zinc, boron, aluminum, silicon, tin, lanthanum and cerium, oxides, halides, water Examples include oxides, alkoxides, and aliphatic or aromatic carboxylates.

Furthermore, other known esterification catalysts, transesterification catalysts, polycondensation catalysts, nucleating agents, inorganic fillers, lubricants, slip agents, anti-blocking agents, stabilizers, antistatic agents, as long as the effects of the present invention are not impaired. A necessary amount of various additives such as an agent, an antifogging agent and a pigment may be contained.
The polyester resin of the present invention can be produced by a raw material slurry preparation method, an esterification method or a transesterification method, and a method by melt polymerization according to a conventionally known method. Further, it can be produced by solid-phase polymerization after that, and if necessary, heat treatment in water.

  First, a dicarboxylic acid component containing an aromatic dicarboxylic acid component as a main component or an ester derivative component of a dicarboxylic acid, a diol component containing ethylene glycol as a main component, other copolymerization monomers, and other auxiliary compounds as required. Stir to prepare the raw slurry. In that case, the molar ratio of the diol component to the dicarboxylic acid component is usually 1.0 to 1.5, and the molar ratio of the diol component to the ester derivative component of the dicarboxylic acid is usually 1.5 to 2.5.

Next, a low-molecular weight polyester is produced from the raw slurry by an esterification method or a transesterification method.
The esterification method is a method of obtaining a low-molecular weight polyester by directly performing an esterification reaction under pressure using, for example, terephthalic acid, ethylene glycol, or other copolymer components. The transesterification method is a method of obtaining a low molecular weight product of a polyester by conducting an ester exchange reaction using an ester derivative of a dicarboxylic acid instead of dicarboxylic acid, for example, dimethyl terephthalate as a raw material and using a considerable amount of an ester exchange catalyst. is there. In the transesterification method, the transesterification catalyst may adversely affect the color tone of the polyester resin and the amount of acetaldehyde. On the other hand, since the esterification method does not require a transesterification catalyst, the color tone and the amount of acetaldehyde of the resulting polyester resin are relatively good. Therefore, the esterification method is preferable for obtaining the polyester resin of the present invention.

For example, when terephthalic acid and ethylene glycol are used as raw materials, the esterification method is usually heated and stirred for 1 to 10 hours at a temperature of 240 to 280 ° C. and a pressure of 0 to 4 × 10 ⁵ Pa relative to atmospheric pressure. Done.
At that time, the esterification rate of the low molecular weight polyester as the esterification reaction product or the transesterification reaction product (ratio of the esterification by reacting with the diol component out of all the carboxyl groups of the raw dicarboxylic acid component) is 95. % Or more is preferable.

  Next, the obtained polyester low-polymer is subjected to a polycondensation reaction by melt polymerization. Melt polymerization is performed by heating the polyester low-polymer in the presence of a polymerization catalyst and gradually reducing the pressure. For example, when terephthalic acid and ethylene glycol are used as raw materials, the normal temperature is 250 to 290 ° C., the pressure is gradually reduced from normal pressure, and finally the normal pressure is normally 1333 to 13.3 Pa (about 10 to 0.1 Torr). ). As the polymerization catalyst, the aforementioned titanium compound is used. The amount used is such that the content of titanium atoms per ton of the polyester resin obtained as described above is 0.02 to 1.0 mol. If necessary, (1) phosphorus compound, (2) at least one of group Ia element compound excluding hydrogen, group IIa element compound or manganese compound, and if necessary, (3) germanium compound is used in combination. .

  These catalyst components can be added at any stage prior to the melt polymerization reaction step. The order of addition of these components is as follows: phosphorus compound, group Ia compound excluding hydrogen, group IIa compound and manganese. It is preferable to add in the order of at least one metal compound selected from compounds and a titanium compound. When a germanium compound or other metal component is used, it is added after the phosphorus compound. The germanium compound is preferably added before or after the titanium compound, at the same stage as the titanium compound, or at the same stage as the group Ia compound or / and the group IIa compound excluding hydrogen, and the group Ia compound or / and IIa excluding hydrogen. More preferably, it is added at the same stage as the group compound.

  When the order of addition is this order, the color tone and amount of by-products of the resulting polyester resin are good. In addition, since the addition order is this order, the polyester resin obtained after melt polymerization or further solid-phase polymerization is subjected to heat treatment in water, which will be described later. Can be good. In particular, when a germanium compound is added, the germanium compound is generally volatilized out of the system during the polymerization of the polyester, but the addition order is this order, which increases the residual rate of the germanium compound in the polymerization system, The use efficiency of the expensive germanium compound is increased and the productivity is improved.

  The specific addition step of each compound is at least one selected from the group consisting of a phosphorus compound, then a group Ia compound excluding hydrogen, a group IIa compound and a manganese compound before the end of the esterification reaction and before the polycondensation reaction. A seed metal compound and then a titanium compound can be added in a time interval (for example, 5 minutes) sufficient for each compound to diffuse well into the reaction vessel, or the phosphorus compound can be added to the raw slurry. Alternatively, it may be added to the initial stage of the esterification reaction, then a metal compound other than the phosphorus compound and the titanium compound may be added to the final stage of the esterification reaction, and further the titanium compound may be added to the initial stage of the polycondensation.

Moreover, after completion | finish of esterification, in the middle of piping which transfers an esterification reaction product from an esterification reaction tank to a polycondensation tank, phosphorus compound addition piping, addition piping of metal compounds other than a phosphorus compound and a titanium compound, titanium compound The addition pipes can be connected in this order and added from each of these pipes.
In particular, in the esterification method continuous production method, the phosphorus compound is added in a slurry preparation step, and at least one metal compound selected from the group consisting of a group Ia compound excluding hydrogen, a group IIa compound, and a manganese compound Alternatively, the titanium compound and the germanium compound are preferably added after the esterification reaction step, and are selected from the group consisting of a group Ia compound excluding the hydrogen, a group IIa compound, and a manganese compound. At least one metal compound or the germanium compound is added in the esterification reaction step, and the titanium compound is added to a transfer pipe or a polycondensation tank of a polyester low molecular weight product as an esterification reaction product to the polycondensation tank. It is particularly preferred that

The polyester resin obtained by the melt polymerization as described above is usually melt-extruded into a strand shape, extracted from the reactor, and then cut into granules (chips) by a cutter.
The polyester resin obtained by melt polymerization is further solid-phase polymerized as necessary. In solid-phase polymerization, polyester resin granules (chips) obtained by melt polymerization are heated, dried and crystallized, and then subjected to a polycondensation reaction at a temperature below the melting point under reduced pressure or in an inert gas stream. The polyester is excellent in color tone because it is carried out at a temperature lower than that of melt polymerization, and it is preferable because the amount of by-product of cyclic low monomer and acetaldehyde is reduced by solid phase polymerization. .

A specific heat treatment method for solid phase polymerization is usually a polyester granule at a temperature of 60 ° C. to 180 ° C. under an inert gas such as nitrogen, argon or carbon dioxide in a dry state or under an inert gas containing water vapor or water vapor. It is carried out by holding the body, drying and crystallizing the resin, and holding it under an inert gas at a temperature ranging from the melting point of the resin to (melting point-80 ° C), usually within 50 hours. The Alternatively, the polyester resin granules are usually held at a temperature of 60 to 180 ° C. under a reduced pressure of not more than 2.6 × 10 ³ Pa in absolute pressure, and the resin is dried and crystallized. It is carried out by maintaining the temperature within the range of usually 50 hours or less at a temperature in the range of from melting point to (melting point −80 ° C.).

  In this case, the concentration of oxygen contained in the reaction vessel is preferably 3 ppm or less in terms of color tone, and more preferably 1 ppm or less. When the oxygen concentration is high, the color tone and the amount of acetaldehyde of the solid phase polymerized polyester tend to deteriorate. The solid phase polymerization is preferably performed while the polyester particles are fluidized by an appropriate method such as a rolling method or a gas fluidized bed method so that the polyester particles do not stick together.

  The polyester resin obtained through the melt polymerization or solid phase polymerization as described above is heated with water or water vapor for the purpose of further reducing by-products such as acetaldehyde and cyclic trimer during molding. It is preferable to perform a contact treatment (hereinafter referred to as “underwater heat treatment”). As conditions for the underwater heat treatment, for example, it can be carried out by contacting with water vapor at 60 ° C. or higher or water vapor-containing gas for 30 minutes or longer, or by immersing in water at 40 ° C. or higher for 10 minutes or longer.

Each of these production steps can be carried out either batchwise or continuously, but a continuous method is preferred in terms of production cost, color tone, crystallization speed, and the like.
The polyester resin of the present invention is formed into a bottle or the like by, for example, forming it into a preform by injection molding and then performing stretch blow molding or by blow molding a parison formed by extrusion molding. After being formed into a sheet by extrusion molding, it is formed into a tray or container by thermoforming, or the sheet is biaxially stretched into a film or the like, which is particularly useful in the food and beverage packaging field. . Among them, it is suitable for forming a bottle by a blow molding method in which a preform obtained by injection molding is biaxially stretched, for example, liquid seasonings such as carbonated beverages, alcoholic beverages, soy sauce, sauces, mirin, dressings, etc. In addition, the container is preferably used as a container that is required to have heat resistance, such as fruit juice drinks, drinks such as tea and mineral water, by heat setting.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. Various measurement methods and evaluation methods in the examples are as follows.
1. Quantitative determination of atoms in resin 2.5 g of sample resin was carbonized with hydrogen peroxide in a conventional manner in the presence of sulfuric acid, completely separated and then made up to 50 ml with distilled water.
Using a “JY46P type” ICP-AES (high frequency inductively coupled plasma emission spectrometer) manufactured by YVON, it was quantified by plasma emission spectroscopy and converted to a molar amount (mol / ton) in 1 ton of polyester resin.
2. Intrinsic viscosity 0.25 g of freeze-ground sample resin is mixed with a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio 1/1) so that the concentration (c) is 1.0 g / dl. It was dissolved at 110 ° C. for 20 minutes. Using an Ubbelohde capillary viscosity tube, the relative viscosity ηrel with the solvent was measured at 30 ° C., and ηsp / c was determined from the specific viscosity (ηsp) determined from this relative viscosity ηrel-1 and the concentration c. When η is 0.5 g / dl, 0.2 g / dl, and 0.1 g / dl, ηsp / c is obtained, and from these values, ηsp / when the concentration c is extrapolated to 0 c was determined as an intrinsic viscosity η (dl / g).
3. Hunter color coordinate b value Sample resin granules (particle weight 15-30 mg) are filled into a measuring cell (light receiving part made of quartz glass) having an inner diameter of 36 mm and a depth of 15 mm, and 300A manufactured by Nippon Denshoku Industries Co., Ltd. Using a colorimetric color difference meter, the measurement cell was rotated 90 degrees by the reflection method and measured four times, and the simple average value was obtained as b value. During the measurement, the apparatus was previously allowed to stand for 4 hours or more after the power was turned on, so that it was sufficiently stabilized.
4). Acetaldehyde content 5.0 g of sample resin granules (grain weight 15-30 mg) are precisely weighed, sealed in a 50 ml internal microbomb with pure water 10.0 ml under a nitrogen seal, heated at 160 ° C. for 2 hours, Acetaldehyde in the resin was extracted into water. The amount of acetaldehyde in the extract was quantified using GC-14A gas chromatography manufactured by Shimadzu Corporation with isobutyl alcohol as an internal standard.
5. Cyclic trimer content 4.0 mg of sample resin was precisely weighed and dissolved in 2 ml of a mixed solution of chloroform / hexafluoroisopropanol (volume ratio 3/2), and further diluted by adding 20 ml of chloroform. To this was added 10 ml of methanol to reprecipitate the sample, followed by filtration to obtain a filtrate. After the filtrate was evaporated to dryness, the residue was dissolved in 25 ml of dimethylformamide. The amount of cyclic trimer (cyclotriethylene terephthalate) in this solution was quantified by LC-10A type liquid chromatography manufactured by Shimadzu Corporation.
6). Bottle Molding Evaluation After sample resin granules (grain weight 15-30mg) are dried at 130 ° C for 10 hours with a vacuum dryer, cylinder setting is performed with an injection molding machine ("FE-80S" manufactured by Nissei Plastic Industry Co., Ltd.). Temperature 280 ° C., back pressure 5 × 10 ⁵ Pa, injection rate 45 cc / second, holding pressure 30 × 10 ⁵ Pa, mold temperature 20 ° C., molding cycle about 40 seconds, outer diameter 29.0 mm, height 165 mm, average A test tubular preform (preform) having a wall thickness of 3.7 mm and a weight of 60 g was injection molded. The preform was heated in a near-infrared irradiation furnace equipped with a quartz heater for 70 seconds and then left at room temperature for 25 seconds to make the temperature distribution inside the preform uniform. After that, it is immediately sandwiched in a mold of a predetermined shape adjusted to 130 ° C., and stretched in the height direction of the bottle with a stretching rod, and blow pressure 7 × 10 ⁵ Pa for 1 second, and further 30 × 10 ⁵ Pa for 5 seconds. After blowing, it was air-cooled to take out a bottle having an average barrel thickness of about 350 μm and an internal volume of about 1.5 liters.

The acetaldehyde odor and color tone of the obtained bottle were evaluated by the following methods.
(1) Acetaldehyde odor: The obtained bottle was sealed with a cap and heated in an oven at 50 ° C. for 1 hour, and the acetaldehyde odor inside the taken out bottle was evaluated by a sensory test. A case where the acetaldehyde odor was very good with very little acetaldehyde was rated as ◎, a case where the acetaldehyde odor was good as good as ○, and a case where the acetaldehyde odor was attached to the nose.
(2) Color tone: The color tone of the stopper part of the obtained bottle was visually evaluated. The case where the plug portion was colorless and transparent was good, ◯, the case where the plug portion was slightly yellowish but no problem in practical use, and the case where the plug portion was clearly yellowish and poor were marked as x.

Example 1
A polyester resin was produced by the following operation using a batch polymerization equipment consisting of one slurry tank, one esterification tank, and one melt polymerization tank.

A raw slurry consisting of 43 kg (260 mol) of terephthalic acid and 19 kg (312 mol) of ethylene glycol was prepared in a slurry tank. This raw slurry was sequentially fed over 4 hours to an esterification tank previously charged with about 60 kg of bishydroxyethyl terephthalate and maintained at a relative pressure of 1.2 × 10 ⁵ Pa at 250 ° C. and atmospheric pressure. The esterification reaction was further allowed to proceed for 1 hour, and the resulting esterified product was transferred to a melt polymerization tank. Next, ethyl acid phosphate, magnesium acetate, and tetra-n-butyl titanate were sequentially added as an ethylene glycol solution from a pipe connected to the melt polymerization tank at intervals of 5 minutes. These catalyst components were used in amounts such that the contents of P, Mg and Ti in one ton of the obtained resin were 0.840, 1.974 and 0.021 mol, respectively.

The temperature of the system was raised from 250 ° C. to 280 ° C. in 2 hours and 30 minutes, and in 60 minutes, the pressure was reduced from normal pressure to absolute pressure of 4.0 × 10 ² Pa. A melt polymerization reaction is performed for a time when the viscosity η ₁ is 0.55, and the obtained resin is extracted in a strand form from an outlet provided at the bottom of the reaction vessel, cooled with water, cut into a chip shape, and an intrinsic viscosity η of about 50 kg. _{1 A} 0.55 dl / g melt polymerized polyester resin was produced.

Subsequently, the obtained melt-polymerized polyester resin was continuously supplied into a stirred crystallizer maintained at about 160 ° C. so as to have a residence time of about 5 minutes, and crystallized. The crystallized resin was further dried in an IPHH-201 type inert oven manufactured by ESPEC under a nitrogen stream of 40 L / min (oxygen concentration 2 ppm) at 160 ° C. for 2 hours, and then the intrinsic viscosity at 210 ° C. was 0.753 dl. / G for a time to perform solid phase polymerization.
Various physical property values and evaluation results of the obtained polyester resin are shown in Table 1.

Examples 2 and 3
A polyester resin was obtained in the same manner as in Example 1 except for changing as described in Table-1. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Examples 4-7
From the pipe connected to the melt polymerization tank, ethyl acid phosphate, magnesium acetate, tetra-n-butyl titanate, and germanium dioxide are sequentially added as an ethylene glycol solution at intervals of 5 minutes, and the addition amount as shown in Table-1 A polyester resin was obtained in the same manner as in Example 1 except that. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Example 8
The polyester resin obtained in Example 4 was immersed in hot water at 90 ° C. for 4 hours and heat-treated in water to obtain a polyester resin. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Examples 9, 10
From a pipe connected to the melt polymerization tank, ethyl acid phosphate, a mixed solution of magnesium acetate and germanium dioxide, and tetra-n-butyl titanate as ethylene glycol solution are sequentially added at intervals of 5 minutes. A melt-polymerized polyester resin was produced in the same manner as in Example 1 except that the residual amount was added as shown in Table 1.

Next, the obtained melt-polymerized polyester resin was put into a double-cone rolling solid phase polymerization tank having an internal volume of 100 L, and the inside of the tank was depressurized to a vacuum with an absolute pressure of 1.3 × 10 ² Pa or less. The pressure was restored three times at an oxygen concentration of 2 ppm, and the system was purged with nitrogen. The inside of the system was again evacuated to an absolute pressure of 1.3 × 10 ² Pa (theoretical oxygen concentration of about 2 ppb), and the temperature was raised from room temperature to 215 ° C. over 18 hours while rolling the polymerization tank at about 30 rpm, and the resin was dried. Crystallized. Subsequently, solid state polymerization was performed at 1.3 × 10 ² Pa and 215 ° C. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Example 11
The polyester resin obtained in Example 9 was immersed in warm water at 90 ° C. for 4 hours, and subjected to heat treatment in water to obtain a polyester resin. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Comparative Examples 1-5
A polyester resin was obtained in the same manner as in Example 1 except that the catalyst and the phosphorus compound shown in Table-1 were used and the addition order shown in Table-1 was added sequentially at intervals of 5 minutes. Various physical properties and evaluation results of the obtained polyester resin are shown in Table 1.

Claims (9)

A polyester resin obtained by polymerizing a dicarboxylic acid component mainly composed of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol component mainly composed of ethylene glycol in the presence of a catalyst containing a titanium compound. A polyester resin containing 0.002 to 1.0 mole of titanium atoms (Ti) per ton of the polyester resin and having the following physical properties.
[Equation 1]
Intrinsic viscosity ≧ 0.70 dl / g
Hunter color coordinate b value ≦ 4
Acetaldehyde content ≦ 5.0 (ppm) 2. The polyester resin according to claim 1, wherein the cyclic trimer content (CT ₀ : wt%) is 0.50 wt% or less.   0.02-4 mol of phosphorus atom per ton of polyester resin, and 0.04-5 mol of at least one atom selected from the group consisting of group Ia atoms, group IIa atoms and manganese atoms excluding hydrogen It contains, The polyester resin of Claim 1 or 2 characterized by the above-mentioned. At least one selected from the group consisting of titanium atom content Ti (mole) per one ton of polyester resin, phosphorus atom content P (mole), and group Ia atoms, group IIa atoms and manganese atoms excluding hydrogen The polyester resin according to claim 3, wherein the content M (mol) of the atom satisfies the relationship of the following formula.
[Equation 2]
P / Ti ≧ 1
1 ≧ P / (Ti + M) ≧ 0.1
1 ≧ P / M> 0 The content Ti (mol) of titanium atoms per ton of polyester resin and the content M (mol) of at least one atom selected from the group consisting of group Ia atoms, group IIa atoms and manganese atoms excluding hydrogen are as follows: The polyester resin according to claim 4, wherein the relationship of the formula is satisfied.
[Equation 3]
2.5 ≦ M / Ti ≦ 250   The polyester resin according to any one of claims 1 to 5, wherein the polyester resin contains 0 to 0.4 mol of germanium atoms per ton of the polyester resin.   7. 95 mol% or more of dicarboxylic acid component is terephthalic acid or 2,6-naphthalenedicarboxylic acid, and 95 mol% or more of diol component is ethylene glycol. Polyester resin.   Esterification of a dicarboxylic acid component having an aromatic dicarboxylic acid as a main component with a diol component having an ethylene glycol as a main component, and then at least selected from a titanium compound, a phosphorus compound and a group Ia atom excluding hydrogen, a group IIa atom and manganese The polyester resin according to any one of claims 1 to 7, which is obtained by polymerizing the esterified product in the presence of a compound of one kind of atom.   The polyester resin according to any one of claims 1 to 8, which is substantially free of antimony and cobalt.