JP2007277305A - Thermoplastic polyester, method for producing the same, and film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic polyester suitable for high quality films excellent in film moldability/sustained heat stability, having no defects and excellent in color hue. <P>SOLUTION: By reacting [A] 1, 4-butane diol, [B] a polyalkylene ether glycol having 500-6000 molecular weight, [C] a chain branching agent, [D] a lower alkyl ester of a difunctional carboxylic acid comprising terephthalic acid as a main component and/or [E] a difunctional carboxylic acid comprising dimethyl phthalate as a main component in the presence of a titanium compound, the thermoplastic polyester containing 5-35 wt.% rate of a structural unit derived from [B], 0.05-10 rate expressed by ä(molar quantity of [C])/(molar quantity of [D] and [E])}x100, 10-120 ppm rate of titanium atom and 0.01-0.4 wt.% hindered phenol-based heat stabilizer is produced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a thermoplastic polyester, a method for producing the same, and a film, and more specifically, a thermoplastic polyester suitable for a high-quality film having excellent film moldability and staying heat stability, no defects such as fish eyes, and excellent color tone, and The present invention relates to a production method thereof and a film using the same.

  Among thermoplastic polyester resins, polybutylene terephthalate is a typical engineering plastic. This polybutylene terephthalate is easy to mold, mechanical properties, heat resistance, chemical resistance, fragrance retention, and other physical and chemical properties, so it can be used for automobile parts, electrical / electronic parts, Widely used for injection molding products such as precision equipment parts. In recent years, taking advantage of its excellent properties, it has been widely used in fields such as films, sheets, monofilaments and fibers.

However, when used as a film, polybutylene terephthalate has a drawback of being hard. Then, what gave the softness | flexibility by copolymerizing polytetramethylene ether glycol etc. is proposed.
For example, Patent Document 1 discloses a process for producing a polyalkylene ether glycol copolymer polybutylene terephthalate containing 39% or more of a polyalkylene ether glycol as a whole, as is apparent from the examples.

Patent Document 2 discloses a method for producing a copolymer in which a polyester, polyether alcohol, and a chain branching agent such as pentaerythritol are heated and melted in a reaction tank and reacted under reduced pressure.
Furthermore, Patent Document 3 discloses a polyester resin composed of an aromatic dicarboxylic acid component, a chain branching agent, 1,4-butanediol, and polyalkylene glycol.

JP 2002-528579 A JP 2000-169564 A JP 2002-308968 A

  However, in the copolyester obtained by the production method described in Patent Document 1, the amount of polyalkylene ether glycol is too large and the strength is lowered. Furthermore, in the production method described in Patent Document 1, Irganox 1330, ie, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) is used as a heat stabilizer. ) Contains a large amount of benzene. For this reason, when a film is formed, yellow or red coloring of the film due to the hindered phenol heat stabilizer occurs.

Further, unlike the method of melt polymerization from monomers, the method described in Patent Document 2 is a method in which a polymer is further reacted, resulting in poor production efficiency. Furthermore, although only tetrabutyl titanate is used as a reaction catalyst, when only tetrabutyl titanate is used in melt polymerization, the polymerization rate is slow and productivity is poor.
Further, in the method described in Patent Document 3, since a large amount of tetrabutyl titanate is added as a catalyst, the polymerization rate is slow and the residence heat stability is inferior.

  The present invention has been made in view of the above circumstances, and its purpose is thermoplasticity suitable for a high-quality film that is excellent in film moldability and residence heat stability, has no defects such as fish eyes, and has excellent color tone. An object of the present invention is to provide polyester with high production efficiency and to provide a film using the polyester.

The present invention has been made to solve the above-described problems, and the gist thereof is [A] 1,4-butanediol, [B] polyalkylene ether glycol having a molecular weight of 500 to 6000, and [C]. [X] a chain branching agent, and [D] a bifunctional carboxylic acid containing terephthalic acid as a main component and / or a lower alkyl ester of a bifunctional carboxylic acid containing [E] dimethyl terephthalate as a main component. A thermoplastic polyester obtained through a reaction step in which reaction is performed in the presence of a titanium compound, each component amount satisfying the following conditions (1) to (3), and [F] a hindered phenol-based heat stabilizer is It exists in the thermoplastic polyester characterized by containing 0.01 to 0.4 weight% with respect to 100 weight% of plastic polyester.
Condition (1): [B] The proportion of the structural unit derived from polyalkylene ether glycol having a molecular weight of 500 to 6000 with respect to 100% by weight of the thermoplastic polyester is 5 to 35% by weight.
Condition (2): “{(Mole amount of [C] chain branching agent) / ([D] Bifunctional carboxylic acid having terephthalic acid as main component and [E] Bifunctional having dimethyl terephthalate as main component. The molar ratio of the lower alkyl ester of the carboxylic acid)} × 100 ”is 0.05 to 10.
Condition (3): The ratio of titanium atoms to the thermoplastic polyester is 10 ppm to 120 ppm.

Another gist of the present invention is that [A] 1,4-butanediol, [B] a polyalkylene ether glycol having a molecular weight of 500 to 6000, [C] a chain branching agent, and [D] terephthalic acid. A reaction step of reacting a bifunctional carboxylic acid having a main component and / or a lower alkyl ester of a bifunctional carboxylic acid having [E] dimethyl terephthalate as a main component in the presence of a [X] titanium compound. It is a manufacturing method of thermoplastic polyester, Comprising: Each component amount satisfy | fills the said conditions (1)-(3), [F] hindered phenol type heat stabilizer is 0 with respect to 100 weight% of this thermoplastic polyester. The present invention resides in a method for producing a thermoplastic polyester, comprising a heat stabilizer blending step of blending to contain 0.01 to 0.4% by weight.
Still another subject matter of the present invention lies in a film characterized by comprising the thermoplastic polyester of the present invention.

The thermoplastic polyester of the present invention can be suitably used for a high-quality film that is excellent in film moldability and residence heat stability, has no defects such as fish eyes, and has excellent color tone.
Moreover, according to the method for producing a thermoplastic polyester of the present invention, the thermoplastic polyester of the present invention can be produced with high production efficiency.
Moreover, according to this invention, the film using the said thermoplastic polyester can be provided.

  Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the examples and the like exemplified in the following description, and can be implemented with arbitrary modifications without departing from the gist of the present invention. In the following description, “ppm” represents a ratio based on weight. [A], [B], [C], [D], [E], [F], [G], [X], and [Y] used in this specification distinguish each element. It is a symbol for.

The thermoplastic polyester of the present invention comprises [A] 1,4-butanediol, [B] a polyalkylene ether glycol having a molecular weight of 500 to 6000 (hereinafter abbreviated as “PAEG” as appropriate), and [C] a chain branching agent. And [D] a bifunctional carboxylic acid containing terephthalic acid as a main component (hereinafter referred to as “[D] bifunctional carboxylic acid” as appropriate) and / or a bifunctional compound containing [E] dimethyl terephthalate as a main component. It is a thermoplastic polyester obtained through a reaction step in which a lower alkyl ester of a functional carboxylic acid (hereinafter referred to as “[E] lower alkyl ester” as appropriate) is reacted in the presence of an [X] titanium compound.
The thermoplastic polyester of the present invention contains [F] hindered phenol heat stabilizer in an amount of 0.01 to 0.4% by weight based on 100% by weight of the thermoplastic polyester, and the amount of each component is as follows. Satisfies (1) to (3).
Condition (1): The ratio of [B] structural unit derived from PAEG having a molecular weight of 500 to 6000 (hereinafter referred to as “PAEG unit” as appropriate) to 5 to 35% by weight with respect to 100% by weight of the thermoplastic polyester.
Condition (2): “{(Mole amount of [C] chain branching agent) / ([D] Bifunctional carboxylic acid having terephthalic acid as main component and [E] Bifunctional having dimethyl terephthalate as main component. The molar ratio of the lower alkyl ester of the carboxylic acid)} × 100 ”is 0.05 to 10.
Condition (3): The ratio of titanium atoms to the thermoplastic polyester is 10 ppm to 120 ppm.

[I. Thermoplastic polyester
[I-1. (Glycol component)
In the thermoplastic polyester of the present invention, [A] 1,4-butanediol and [B] PAEG are used as the glycol component. In addition, other glycol components may be used in combination with these.

[[A] 1,4-butanediol]
[A] 1,4-butanediol is a kind of raw material for the thermoplastic polyester of the present invention. Specifically, it is a substance used as a glycol component of the thermoplastic polyester of the present invention.

[[B] polyalkylene ether glycol]
[B] PAEG is a kind of raw material for the thermoplastic polyester of the present invention. Specifically, it is a substance used as a glycol component of the thermoplastic polyester of the present invention. Examples of the polyalkylene ether glycol include polytetramethylene ether glycol (hereinafter, polytetramethylene ether glycol is appropriately abbreviated as “PTMG”), polypropylene ether glycol, polyethylene ether glycol, and the like. Among these, PTMG has a high flexibility imparting effect and is preferable. In addition, PAEG may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

However, in the thermoplastic polyester of the present invention, [B] PAEG has a molecular weight of usually 500 or more, preferably 800 or more, and usually 6000 or less, preferably 3000 or less. [B] When the molecular weight of PAEG is less than 500, there is no effect of imparting flexibility, and when it exceeds 3000, the film becomes incompatible and the transparency and strength of the film decrease.
The molecular weight of PAEG was determined by measuring the terminal glycol concentration of PAEG by esterifying the terminal glycol of PAEG with phthalic anhydride to obtain a phthalate ester, and then titrating this with sodium hydroxide. It can be measured by calculating the number average molecular weight from the terminal OH concentration.

[B] PAEG is used in such an amount that the content of the PAEG unit in the thermoplastic polyester of the present invention satisfies the following condition (1).
Condition (1): The content of the [B] PAEG unit with respect to 100% by weight of the thermoplastic polyester is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, and further preferably 20% by weight or more. Further, it is usually 35% by weight or less, preferably 30% by weight or less. [B] If the content of the PAEG unit is below the lower limit of the above range, the effect of adding [B] PAEG may be lost. If the content exceeds the upper limit, the film strength of the film produced using the thermoplastic polyester of the present invention is high. May decrease.

[Other glycol components]
In the present invention, glycol components other than [A] 1,4-butanediol and [B] PAEG (other glycol components) may be used in combination. Examples of other glycol components include ethylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, poly (oxy) ethylene glycol, diethylene glycol, Examples include alkylene glycols such as triethylene glycol and polymethylene glycol.

Moreover, as other glycol components, it is also possible to use PAEG having a molecular weight outside the above-described molecular weight range.
Furthermore, as other glycol components, ester compounds such as polycaprolactone (terminal diol), polyglycolic acid, and polylactic acid (terminal diol) may be used. Among these, polycaprolactone is particularly preferable, and in this case, the heat resistance of the thermoplastic polyester is improved.

Furthermore, the other glycol components may be used alone or in combination of two or more in any combination and ratio.
However, as the glycol component, [A] 1,4-butanediol and [B] PAEG are used as main components. Thereby, the thermoplastic polyester of the present invention has a structural unit derived from [A] 1,4-butanediol (hereinafter referred to as “1” as appropriate) as a structural unit derived from a glycol component (hereinafter referred to as “glycol unit” as appropriate). , 4-butanediol unit) and [B] PAEG unit as main components. Specifically, in the thermoplastic polyester of the present invention, the content of structural units derived from other glycol components with respect to [A] 1,4-butanediol unit and [B] PAEG unit is usually 50 wt. % Or less, preferably 30% by weight or less, more preferably 10% by weight or less. If it exceeds 50% by weight, the balance between flexibility and strength is impaired. In addition, the minimum of the content rate of the structural unit derived from another glycol component is 0 weight%.

[I-2. Carboxylic acid / ester component]
In the thermoplastic polyester of the present invention, as the carboxylic acid / ester component, [D] a bifunctional carboxylic acid containing terephthalic acid as a main component and [E] a bifunctional carboxylic acid containing dimethyl terephthalate as a main component One or both of the lower alkyl esters are used. In addition, other carboxylic acid / ester components may be used in combination with these. Here, “carboxylic acid / ester component” is used as a term that refers to both a carboxylic acid component and an ester component.

[[D] Bifunctional carboxylic acid]
[D] The bifunctional carboxylic acid is a kind of raw material for the thermoplastic polyester of the present invention. Specifically, it is a substance used as a carboxylic acid component of the thermoplastic polyester of the present invention. In the present invention, as the [D] difunctional carboxylic acid, one having terephthalic acid as a main component is used. Here, having terephthalic acid as the main component means that the ratio of terephthalic acid in the [D] difunctional carboxylic acid is usually 60% by weight or more, preferably 80% by weight or more. Preferably, it means 90% by weight or more. The upper limit is 100% by weight.

[D] When the bifunctional carboxylic acid contains a bifunctional carboxylic acid component other than terephthalic acid, the bifunctional carboxylic acid component is not limited. Examples of bifunctional carboxylic acid components other than terephthalic acid include: naphthalenedicarboxylic acid such as isophthalic acid and 2,6-naphthalenedicarboxylic acid; aromatic dicarboxylic acid such as diphenyldicarboxylic acid such as 4,4-diphenyldicarboxylic acid Acids; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.
In addition, bifunctional carboxylic acid components other than terephthalic acid may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

[[E] lower alkyl ester]
[E] The lower alkyl ester is a kind of raw material for the thermoplastic polyester of the present invention. Specifically, it is a substance used as a carboxylic acid component of the thermoplastic polyester of the present invention. In the present invention, [E] lower alkyl ester having dimethyl terephthalate as a main component is used. Here, dimethyl terephthalate is the main component, specifically, the ratio of dimethyl terephthalate in [E] lower alkyl ester is usually 60% by weight or more, preferably 80% by weight or more, more preferably It means 90% by weight or more. The upper limit is 100% by weight.

  [E] When the lower alkyl ester contains a lower alkyl ester component of a bifunctional carboxylic acid other than dimethyl terephthalate, the lower alkyl ester component is not limited. Examples of lower alkyl ester components of bifunctional carboxylic acids other than dimethyl terephthalate include naphthalenedicarboxylic acids such as isophthalic acid and 2,6-naphthalenedicarboxylic acid; diphenyldicarboxylic acids such as 4,4-diphenyldicarboxylic acid, etc. Examples include aromatic dicarboxylic acids; cycloaliphatic dicarboxylic acids such as cycloaliphatic dicarboxylic acids; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid; and the like.

  Here, examples of the lower alkyl group that forms a lower alkyl ester by binding to a difunctional carboxylic acid include alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, and a butyl group. It is done. These alkyl groups may be linear or cyclic, and may have a branched chain.

Among them, it is preferable to use a methyl group as a lower alkyl group, that is, to use a methyl ester as a lower alkyl ester component of a bifunctional carboxylic acid other than dimethyl terephthalate. If a methyl ester is used, the by-product in the transesterification reaction is methanol having a low boiling point, which is preferable because the transesterification reaction is faster than other alkyl esters.
In addition, the lower alkyl ester component of bifunctional carboxylic acid other than dimethyl terephthalate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

[Ratio of component [D] to component [E]]
One of [D] difunctional dicarboxylic acid and [E] lower alkyl ester may be used, or both may be used in combination. Moreover, when using both together, the blending ratio of [D] bifunctional dicarboxylic acid and [E] lower alkyl ester is arbitrary.
However, in order to facilitate separation and recovery of the distillate generated in the esterification reaction or transesterification reaction, only one of [D] bifunctional dicarboxylic acid and [E] lower alkyl ester should be used. It is preferable to make it.

[Other carboxylic acid / ester components]
In the present invention, a carboxylic acid / ester component (other carboxylic acid / ester component) other than the above [D] difunctional dicarboxylic acid and [E] lower alkyl ester may be used in combination. Examples of other carboxylic acid / ester components include higher alkyl esters.

Furthermore, the other carboxylic acid / ester components may be used alone or in combination of two or more in any combination and ratio.
However, as the carboxylic acid / ester component, the above [D] difunctional dicarboxylic acid and / or [E] lower alkyl ester is used as a main component. As a result, the thermoplastic polyester of the present invention has a structural unit derived from the above-mentioned [D] bifunctional dicarboxylic acid as a structural unit derived from a carboxylic acid / ester component (hereinafter appropriately referred to as “carboxylic acid / ester unit”) ( Hereinafter, a structural unit derived from a “difunctional dicarboxylic acid unit” and / or [E] lower alkyl ester as appropriate (hereinafter, appropriately referred to as “lower alkyl ester unit”) is contained as a main component. Specifically, in the thermoplastic polyester of the present invention, the content of structural units derived from other carboxylic acid / ester components with respect to [D] difunctional dicarboxylic acid units and [E] lower alkyl ester units is usually It is 40% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less. This is because strength and heat resistance are reduced. In addition, the minimum of content of the structural unit derived from another carboxylic acid / ester component is 0 weight%.

[Ratio of glycol component to carboxylic acid / ester component]
In the thermoplastic polyester of the present invention, the ratio of the total molar amount of glycol units to the total molar amount of carboxylic acid / ester units is arbitrary as long as the effects of the present invention are not significantly impaired. However, the ratio of the total molar amount of carboxylic acid / ester units to the total molar amount of glycol units and carboxylic acid / ester units is usually 0.30 or more, preferably 0.40 or more, more preferably 0.45 or more, Also, it is usually 0.70 or less, preferably 0.60 or less, more preferably 0.55 or less. Among them, it is particularly preferable that the ratio of the total molar amount of glycol units and the total molar amount of carboxylic acid / ester units be equal.

[I-3. Chain branching agent]
The thermoplastic polyester of the present invention contains a specific amount of [C] chain branching agent. [C] By blending a specific amount of the chain branching agent, the thermoplastic polyester of the present invention can have an appropriate melt viscosity characteristic, and its moldability can be improved.

  [C] Although there is no restriction | limiting in particular in a chain branching agent, For example, a trifunctional or more than trifunctional organic compound can be used combining a hydroxyl group and a carboxyl group. That is, an organic compound having one or both of a hydroxyl group and a carboxyl group and the total number of hydroxyl groups and carboxyl groups of the organic compound is 3 or more can be given.

Examples of the organic compound having a trifunctional or higher functional hydroxyl group include trimethylolpropane, pentaerythritol, di-trimethylolpropane, 1,1,4,4-tetrakis (hydroxymethyl) cyclohexane, and the like.
Examples of the organic compound having a trifunctional or higher functional carboxyl group include trimellitic acid, trimesic acid, 1,1,2,2-ethanetetracarboxylic acid, and the like.

Furthermore, these lower alkyl esters and anhydrides can also be used as chain branching agents. Examples of the trifunctional or higher functional lower alkyl ester include ethyl ester, propyl ester, and butyl ester. Specific examples include trimellitic acid trimethyl ester, trimellitic acid tris-2-ethylhexyl, and the like. Moreover, as an anhydride, trimellitic anhydride etc. are mentioned, for example.
Examples of the trifunctional or higher functional organic compound having both a hydroxyl group and a carboxyl group include malic acid, citric acid, 3-hydroxyglutaric acid, dihydroxyglutaric acid, and the like.

  In addition, [C] chain branching agent may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. For example, when using a trifunctional or higher functional carboxyl group and its lower alkyl ester in combination, use trimellitic acid and trimellitic acid trimethyl ester, trimellitic acid and trimellitic acid tris-2-ethylhexyl in combination. Can do. When a trifunctional or higher functional hydroxyl group is used in combination, trimethylolpropane and pentaerythritol can be used in combination. Further, when a trifunctional or higher functional carboxyl group and a trifunctional or higher functional hydroxyl group are used in combination, trimellitic anhydride and trimethylolpropane can be used in combination.

  Among these, as the [C] chain branching agent, it is preferable to use one or more selected from pentaerythritol, trimethylolpropane, trimellitic acid, trimellitic acid trimethyl ester, and trimellitic anhydride. It is preferred to use erythritol.

  Moreover, although the number of the functional groups which [C] chain branching agent has is arbitrary, 3 or 4 functional groups are preferable normally. Since the branching effect is higher when the number of functional groups is larger, the blending amount of the [C] chain branching agent can be reduced. On the other hand, gelation tends to occur during melt polymerization (described later). Therefore, the number of functional groups possessed by the [C] chain branching agent is preferably determined in consideration of the polymerization controllability and the chain branching effect.

Furthermore, the blending amount of the [C] chain branching agent satisfies the following condition (2).
Condition (2): ratio represented by “{(molar amount of [C] chain branching agent) / (molar amount of [D] difunctional carboxylic acid and [E] lower alkyl ester)} × 100” ( The blending ratio) is usually 0.05 or more, preferably 0.10 or more, and usually 10 or less, preferably 5 or less, more preferably 1 or less, and particularly preferably 0.6 or less.
This condition (2) is that the blending molar amount of the [C] chain branching agent is within the above range with respect to the total molar amount of [D] bifunctional carboxylic acid and [E] lower alkyl ester. Represent. [C] When the blending amount of the chain branching agent is less than 0.05, there is no blending effect, and when it exceeds 10, gelation tends to occur and reaction control is difficult.

[I-4. Heat stabilizer)
A specific amount of [F] hindered phenol-based heat stabilizer is added to the thermoplastic polyester of the present invention. Thereby, it becomes possible to improve the thermal stability at the time of melt residence, without producing polymer coloring.

Examples of [F] hindered phenol heat stabilizers include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2. , 4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like. Among these, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is more preferable in terms of thermal stability during melt residence.
In addition, [F] hindered phenol type heat stabilizers may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  In addition, the [F] hindered phenol heat stabilizer is usually 0.01% by weight or more, preferably 0.03% by weight or more, and usually 0.4% by weight based on 100% by weight of the thermoplastic polyester of the present invention. It is contained in an amount of not more than wt%, preferably not more than 0.2 wt%. If the lower limit of this range is not reached, the effect of using the [F] hindered phenol-based heat stabilizer may not be obtained, and if it exceeds the upper limit, the coloring of the thermoplastic polyester becomes remarkably unfavorable.

  In the thermoplastic polyester of the present invention, other kinds of heat stabilizers can be used in combination. There is no restriction | limiting in the heat stabilizer to use together, Moreover, 1 type may be used independently and 2 or more types may be used together by arbitrary combinations and a ratio. In particular, when [G] pentaerythritol tetrakis [3-lauryl-thio-propionate] is used in combination, the thermal stability during melt residence can be dramatically improved without coloring the thermoplastic polyester.

  [G] The amount of pentaerythritol tetrakis [3-lauryl-thio-propionate] used is arbitrary, but is usually 0% by weight or more, preferably 0.03% by weight or more, based on 100% by weight of the thermoplastic polyester. Further, it is usually contained in an amount of 0.4% by weight or less, preferably 0.2% by weight or less. Exceeding the upper limit of this range is not preferable because contamination in the distillate during polycondensation increases.

[I-5. titanium〕
The thermoplastic polyester of the present invention contains [A] 1,4-butanediol, [B] PTMG, and [C] chain branching agent, and [D] difunctional carboxylic acid and / or [E]. It is obtained through a reaction step in which a lower alkyl ester is reacted in the presence of [X] titanium compound (titanium catalyst).

[X] The titanium compound acts as a catalyst. [X] Examples of titanium compounds include inorganic titanium compounds such as titanium oxide and titanium tetrachloride, titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate. It is done. Of these, tetraalkyl titanates are preferred, and tetrabutyl titanate is most preferred.
In addition, [X] titanium compounds may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

As described above, the thermoplastic polyester of the present invention contains a titanium atom due to the [X] titanium compound because the titanium compound is present in the reaction system at the time of production. Specifically, the thermoplastic polyester of the present invention contains titanium atoms in an amount that satisfies the following condition (3).
Condition (3): The ratio (content ratio) of titanium atoms to the thermoplastic polyester of the present invention is usually 10 ppm or more, preferably 20 ppm or more, more preferably 30 ppm or more, and usually 120 ppm or less, preferably 100 ppm or less, more preferably. Is 70 ppm or less.
When the content of titanium in the thermoplastic polyester of the present invention is too large, not only the color tone and thermal stability are deteriorated, but also there is a possibility that solution haze and foreign matter increase due to the deactivation of the titanium catalyst. If the amount is too small, the polymerizability may be deteriorated.

  The metal content of the titanium atom is measured by ICP (Inductively Coupled Plasma) -MS (Mass Spectrometer) method after recovering the metal in the polymer by wet ashing.

[I-6. Metal atoms selected from groups 1 and 2 of the periodic table]
In the production of the thermoplastic polyester of the present invention, [B] PTMG is easily decomposed in the presence of the [X] titanium compound. For this reason, when the amount of [X] titanium compound is increased in order to increase the polymerization rate, the amount of the heat stabilizer is usually increased. However, increasing the amount of heat stabilizer leads to deterioration in color tone. Therefore, at the time of production of the thermoplastic polyester of the present invention, at least one metal compound selected from [Y] periodic table group 1 and group 2 as a catalyst (hereinafter referred to as “[Y] metal catalyst for polycondensation” as appropriate). ) Is preferably used. [Y] By using the metal catalyst for polycondensation together with the [X] titanium compound, it becomes possible to increase the polymerization rate compared to the case of using the [X] titanium compound alone, and the color tone and hydrolysis resistance are improved. Also improves. In the following, the metal compound of Group 1 of the periodic table and the metal compound of Group 2 of the periodic table may be referred to as Group 1 metal catalyst and Group 2 metal catalyst, respectively.

[Y] Specific examples of Group 1 metal catalysts among the metal catalysts for polycondensation include various compounds of lithium, sodium, potassium, rubidium, and cesium. Specific examples of the Group 2 metal catalyst include various compounds of beryllium, magnesium, calcium, strontium, and barium. Among these, lithium, sodium, potassium, magnesium, and calcium compounds are preferable from the viewpoints of handling and availability, and catalytic effects. Among these, a lithium or magnesium compound excellent in catalytic effect and color tone is preferable, and a magnesium compound is particularly preferable. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Among these, magnesium acetate is preferable.
In addition, the metal catalyst for [Y] polycondensation may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  In addition, since the metal catalyst for polycondensation [Y] is a compound of at least one metal selected from Groups 1 and 2 of the periodic table as described above, the thermoplastic polyester of the present invention obtained has a periodicity. It contains at least one metal atom selected from Group 1 and 2 of the Table. Specifically, it contains a metal atom of Group 1 of the periodic table such as lithium, sodium, potassium, rubidium and cesium and a metal atom of Group 2 of the periodic table such as beryllium, magnesium, calcium, strontium and barium. become.

  Under the present circumstances, there is no restriction | limiting in content of the at least 1 sort (s) of metal atom chosen from the periodic table group 1 and 2 group which the thermoplastic polyester of this invention contains. However, the thermoplastic polyester of the present invention contains at least one metal atom selected from Groups 1 and 2 of the Periodic Table, usually 5 ppm or more, preferably 10 ppm or more, and usually 100 ppm or less, preferably 70 ppm or less. It is desirable. If the content exceeds the upper limit of this range, the polymerization activity during the synthesis of the thermoplastic polyester of the present invention may reach its peak, and the thermal stability of the thermoplastic polyester of the present invention may also decrease. On the other hand, if the content is below the lower limit of this range, the effect of using the [Y] metal catalyst for polycondensation may not be obtained.

  Furthermore, the thermoplastic polyester of the present invention contains at least one metal atom selected from Groups 1 and 2 of the Periodic Table has a predetermined relationship with the titanium atom contained in the thermoplastic polyester of the present invention. It is desirable to satisfy. That is, in the thermoplastic polyester of the present invention, the molar ratio of titanium atoms to at least one metal atom selected from groups 1 and 2 of the periodic table ([number of moles of titanium atoms] / [groups of periodic table 1 and The total number of moles of at least one metal atom selected from Group 2] is usually 0.30 or more, preferably 0.40 or more, and usually 1.50 or less, preferably 1.20 or less, more preferably It is 1.00 or less, More preferably, it is 0.80 or less. If the lower limit of this range is not reached, the polymerization rate reaches a peak, and if it exceeds the upper limit, the blending effect of the metal catalyst for [Y] polycondensation cannot be obtained.

  The metal content of a metal atom selected from Group 1 and Group 2 of the periodic table can be measured in the same manner as the method for measuring the content of titanium atom.

[I-7. Other catalysts, reaction aids, etc.)
When producing the thermoplastic polyester of the present invention, other catalysts than the above-mentioned [X] titanium catalyst and [Y] polycondensation metal catalyst may coexist in the reaction system.

  In addition, the catalyst used together with the metal catalyst for [X] titanium and [Y] polycondensation may be used individually by 1 type, and may be used together by 2 or more types by arbitrary combinations and ratios.

In addition to the [X] titanium catalyst and [Y] metal catalyst for polycondensation, antimony compounds such as antimony trioxide, germanium compounds such as germanium dioxide and germanium tetroxide, manganese compounds, zinc compounds, zirconium compounds, Reaction aids such as cobalt compounds, orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, phosphorus compounds such as esters and metal salts thereof may be used.
In addition, these reaction adjuvants may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

[I-8. nature〕
The thermoplastic polyester of the present invention is suitable for use in a high-quality film having excellent film moldability and residence heat stability, no defects such as fish eyes, and excellent color tone. Specifically, the thermoplastic polyester of the present invention usually has the following properties.

[Film formability]
After 5 kg of the thermoplastic polyester of the present invention is vacuum-dried at 120 ° C. for 8 hours, a molding temperature of 250 ° C., a cooling roll temperature of 80 ° C. is taken up by a T-die molding machine (extruder diameter 40 mm, T-die width 600 mm) manufactured by Ikegai Co., Ltd. Attempt to form a film with a thickness of 30 μm at a speed of 3 m / min. At this time, the thermoplastic polyester of the present invention can be stably molded without the difficulty of stable molding such as severe resin dripping from the die. Thus, the thermoplastic polyester of the present invention has an advantage of excellent film moldability.

[Still heat stability]
20 g of the thermoplastic polyester of the present invention is vacuum dried at 120 ° C. for 10 hours. Then, after drying, the polymer was filled in Toyo Seiki Capillograph Type 1B, melted and held at a temperature of 245 ° C. for 60 minutes, and then extracted from a capillary with a diameter of 1 mm and L / D = 10 at an extrusion speed of 50 mm / min to obtain a strand. . This strand is pelletized with a chip cutter, and the intrinsic viscosity is measured. A value obtained by dividing the intrinsic viscosity after the heat treatment by the intrinsic viscosity before the heating is an index value representing the residence heat stability. In the thermoplastic polyester of the present invention, the value obtained by dividing the intrinsic viscosity after the heat treatment by the intrinsic viscosity before heating is usually 0.80 or more, preferably 0.85 or more. The upper limit is not particularly limited, but is usually 1 or less. Thus, the thermoplastic polyester of the present invention has the advantage of excellent residence heat stability. In addition, intrinsic viscosity can be measured by the method demonstrated in the Example mentioned later.

〔Fish eye〕
A fish eye is a defect commonly found in a polymer molded film and refers to a minute fish-like defect that is visually confirmed. When fish eyes are seen, in addition to the case where foreign matter is mixed in the forming raw material, the amount of catalyst in the raw material is so large that it forms aggregates and appears as foreign matter. There is a portion having a high molecular weight locally, and it may appear as a defect due to non-uniform refractive index.

  After 5 kg of the thermoplastic polyester of the present invention is vacuum dried at 120 ° C. for 8 hours, a film having a thickness of 50 μm is obtained using a film molding machine (model ME-20 / 26V2) manufactured by Optical Control Systems. At this time, the cylinder and die temperatures are 250 ° C. This film is measured using a Film Quality Testing System (Optical Control Systems, Inc .: Model FS-5) to measure the number of fish eyes exceeding 200 μm per square meter of the film. In the thermoplastic polyester of the present invention, the number of fish eyes measured is usually 100 or less, preferably 20 or less. The lower limit is 0. Thus, the thermoplastic polyester of the present invention has an advantage that it is suitable for use in producing a film having no defects such as fish eyes.

[End color]
The film formed in the evaluation of the above “film formability” is visually observed in a state of being wound around a paper tube. In this case, the film produced from the thermoplastic polyester of the present invention usually does not exhibit significant coloring on the film end face, and preferably does not color. As described above, the thermoplastic polyester of the present invention is excellent in transparency and has an advantage that it is suitable for producing a packaging film requiring transparency.

[Intrinsic viscosity]
In addition, although there is no restriction | limiting in the intrinsic viscosity (the measuring method is mentioned later) of the thermoplastic polyester of this invention, Usually 0.6 or more, Preferably 0.8 or more, More preferably, it is 0.9 or more, Moreover, usually 2.0 Hereinafter, it is preferably 1.7 or less, more preferably 1.6 or less.

[II. Production method〕
The method for producing the thermoplastic polyester of the present invention includes [A] 1,4-butanediol, [B] PTMG, and [C] chain branching agent, and [D] bifunctional carboxylic acid, and / or [E] It has the reaction process which reacts a lower alkyl ester in presence of [X] titanium compound, The thermoplastic polyester of this invention is obtained through this reaction process.

[II-1. Reaction process)
The specific operation and reaction conditions of the reaction step are not limited as long as the thermoplastic polyester of the present invention is obtained. [A] 1,4-butanediol, [B] PAEG, [C] chain branching agent, [X] titanium compound, and [D] bifunctional carboxylic acid and / or [E] lower alkyl The timing and order of blending the ester into the reaction system are arbitrary as long as the thermoplastic polyester of the present invention can be obtained. Moreover, in the said reaction process, it is preferable to make it react in presence of the metal catalyst for [Y] polycondensation suitably.

  The blending ratio of the glycol component and the carboxylic acid / ester component during production is arbitrary as long as the effects of the present invention are not significantly impaired. However, in the thermoplastic polyester of the present invention, (the sum of molar amounts of [A] 1,4-butanediol unit and [B] PAEG unit) / ([D] bifunctional carboxylic acid unit and [E] lower It is desirable that the value of the sum of the molar amounts of the alkyl ester units is usually 1.0 or more. In order to realize this, at the time of production, the amount of [A] 1,4-butanediol is increased compared to the amount of [A] 1,4-butanediol unit in the obtained thermoplastic polyester. It is desirable to do. This is because [A] 1,4-butanediol is discharged into the gas phase during the reaction, and the amount of [A] 1,4-butanediol in the reaction system is reduced.

Specifically, blended during production (sum of molar amounts of [A] 1,4-butanediol and [B] PAEG) / (molar amount of [D] bifunctional carboxylic acid and [E] lower alkyl ester The preferred value of the sum of
(I) [D] When the molar amount of the bifunctional carboxylic acid ≧ [E] The molar amount of the lower alkyl ester is usually 1.6 or more, and usually 2.5 or less, preferably 2.2 or less. Yes,
(Ii) When the molar amount of [D] bifunctional carboxylic acid <the molar amount of [E] lower alkyl ester is usually 1.1 or more, and usually 2.0 or less, preferably 1.6 or less. is there.
If it is less than the above lower limit value or exceeds the upper limit value, the end group balance may be lost, and the reaction may not proceed.

  In addition, in the above reaction step, the first step (esterification step, transesterification step) in which an esterification reaction or transesterification reaction between a glycol component and a carboxylic acid / ester component proceeds, and a melt polycondensation reaction proceed. And a second step (melt polycondensation step). Hereinafter, taking this case as an example, the method for producing the thermoplastic polyester of the present invention will be described.

[First step]
In the first step, an esterification reaction or a transesterification reaction between the glycol component and the carboxylic acid / ester component is allowed to proceed. Here, when [D] bifunctional carboxylic acid is used as the carboxylic acid / ester component, the esterification reaction proceeds, and when [E] lower alkyl ester is used as the carboxylic acid / ester component, transesterification occurs. When the reaction proceeds and both [D] bifunctional carboxylic acid and [E] lower alkyl ester are used as the carboxylic acid / ester component, both esterification and transesterification proceed.

In the present invention, the esterification reaction step refers to a reaction until the esterification rate of the oligomer reaches 90%. Here, the esterification rate of the oligomer is calculated by the following formula using the acid value and saponification value obtained as follows.
[Acid value]
The oligomer is dissolved in dimethylformamide and titrated with a 0.1N KOH / methanol solution.
[Saponification value]
The oligomer is hydrolyzed with 0.5N KOH / ethanol solution and back titrated with 0.5N hydrochloric acid.
[Calculation formula for esterification rate]
Esterification rate (%) = ((saponification value−acid value) / saponification value) × 100

In the present invention, the transesterification step refers to a reaction until the transesterification rate of the oligomer reaches 80%.
The transesterification rate of the oligomer is calculated by the following formula using the molar concentration of the dicarboxylic acid unit obtained by measuring the residual alkyl ester using ¹ H NMR having a resonance frequency of 400 MHz and the saponification value.
[Calculation formula of transesterification rate]
Transesterification rate = ((Molar concentration of dicarboxylic acid unit × 2-alkyl ester equivalent) / Molar concentration of dicarboxylic acid unit × 2) × 100

  In the first step, at least [A] 1,4-butanediol, [D] difunctional carboxylic acid, and / or [E] lower alkyl ester are present in the reaction system. At this time, the blending amounts of [A] 1,4-butanediol and [D] difunctional carboxylic acid and / or [E] lower alkyl ester present in the reaction system are as described above.

[B] PAEG and [C] chain branching agent may be independently added to the reaction system before, during and after the first step. [B] PAEG and [C] chain branching agent shall be blended in such a blending amount (blending ratio) that satisfies the conditions (1) and (2). However, it is preferable that [B] PAEG and [C] chain branching agent are present in the reaction system in the first step in order to increase the branching effect, but thermal decomposition of [B] PAEG becomes a problem. In this case, [B] PAEG can be blended after the first step and before the second step. Further, when gelation is a concern during continuous production, the [C] chain branching agent can be added after the first step and before the second step.
When [B] PAEG and [C] chain branching agent were added to the reaction system before and during the first step, the above [A] 1,4-butanediol, [D] bifunctional In addition to the basic carboxylic acid and / or [E] lower alkyl ester, [B] PAEG and [C] chain branching agent will also cause ester reaction and / or transesterification.

  [A] 1,4-butanediol, [B] PAEG, and [C] chain branching agent, and [D] bifunctional carboxylic acid and / or [E] lower alkyl ester are The total amount may be blended into the reaction system at once, or may be blended into the reaction system in two or more portions.

  Furthermore, you may mix | blend a [C] chain branching agent with a reaction system as it is. Further, when a solid [C] chain branching agent is used at room temperature, the [C] chain branching agent is blended after being heated and melted to the melting point, water, 1,4-butanediol, PAEG, etc. You may make it mix | blend, after making it melt | dissolve in this solvent. In particular, when pentaerythritol is used as the chain branching agent, it is preferably blended in the reaction system in a state of being dissolved in 1,4-butanediol at 100 ° C. or higher. In this case, the dissolution concentration of pentaerythritol is arbitrary, but is usually 1% by weight or more, usually 50% by weight or less, preferably 20% by weight or less with respect to 1,4-butanediol. In order to lower the dissolution temperature, it is also possible to first dissolve pentaerythritol in warm water to obtain an aqueous solution having a concentration of 20% by weight or less, and then dilute with 1,4-butanediol.

  [X] Titanium compound may be added to the reaction system before, during and after the first step. However, from the viewpoint of accelerating the esterification reaction and the transesterification reaction, the [X] titanium compound is preferably present in the reaction system in the first step, and therefore preferably blended in the first step. Specifically, it is preferable to mix | blend before the process of a 1st process, or during a process, and it is more preferable to mix | blend with a reaction system before the process of a 1st process. [X] The compounding amount of the titanium compound is set so that the content ratio of titanium atoms in the thermoplastic polyester of the present invention to be produced falls within the above-described range (see condition (3)).

  As will be described later, the [X] titanium compound may be divided and blended into the first step and the second step. In that case, the amount of the [X] titanium compound to be blended in the first step Is usually 35% by weight or more of the titanium compound to be blended, preferably 45% by weight or more, and usually 75% by weight or less, preferably 65% by weight or less. Below the lower limit of this range, the esterification reaction and transesterification reaction will be delayed, and above the upper limit, the polycondensation reaction will be delayed.

  [X] The titanium compound may be blended in the reaction system as it is, but is preferably blended in a state dissolved or diluted in a solvent such as 1,4-butanediol. If the catalyst is not dissolved or diluted, the dispersibility of the catalyst is deteriorated, so that there is a possibility that the reaction rate is lowered or aggregated foreign matters are generated. At this time, the concentration of the [X] titanium compound in the solvent is arbitrary, but is usually 0.01% by weight or more, preferably 0.005% by weight or more, more preferably 0.08% by weight or more, and usually 20%. % By weight or less, preferably 10% by weight or less, more preferably 8% by weight or less.

The reaction conditions in the first step are arbitrary as long as the above esterification reaction and / or transesterification reaction can proceed.
However, the temperature condition is usually 120 ° C. or higher, preferably 150 ° C. or higher, and usually 245 ° C. or lower, preferably 230 ° C. or lower. The reaction time is usually 2 to 4 hours.

  By performing the first step, [A] 1,4-butanediol, [B] PAEG, [C] chain branching agent, and [D] bifunctional carboxylic acid and / or [E] lower alkyl An oligomer in which the ester has reacted is produced. And in the 2nd process mentioned later, this oligomer polycondensation is performed. In addition, when blending [B] PAEG and [C] chain branching agent after the first step, the oligomer does not contain components corresponding to [B] PAEG and [C] chain branching agent. become.

[Second step]
In the second step, the oligomer obtained in the first step is subjected to a polycondensation reaction. At this time, the polycondensation reaction usually proceeds as a melt polycondensation reaction.
When [B] PAEG and / or [C] chain branching agent is not blended in the reaction system in the first step, [B] PAEG and / or [C] chain is added to the reaction system before the second step. Add a branching agent. The blending amount and the state at the time of blending are the same as described in [First Step].

  [X] Titanium compounds are already present in the reaction system because they are usually blended in the first step. However, in this case, the [X] titanium compound is preferably further added to the reaction system in the second step. That is, it is preferable to mix | blend a [X] titanium compound into a 1st process and a 2nd process. Specifically, the [X] titanium compound is usually further added to the reaction system after the first step and before or during the second step. Since the [X] titanium compound blended in the first step is partially deactivated, in the second step (that is, after the step of the first step and before or during the step of the second step) [ X] By adding the titanium compound, the reaction promoting effect in the second step is enhanced. If a large amount of [X] titanium compound is blended in the first step, the deactivated [X] titanium compound may form an aggregate and remain as a foreign substance in the thermoplastic polyester. When PAEG is blended in the process, the PAEG may be decomposed. The state of the [X] titanium compound at the time of blending is the same as described in [First Step]. Moreover, the compounding quantity of [X] titanium compound mix | blends an unblended part out of the whole quantity of [X] titanium compound which should be mix | blended, when [X] titanium compound is already mix | blended at the 1st process, When the [X] titanium compound is not blended in the first step, the total amount of the [X] titanium compound to be blended is blended.

  [Y] The metal catalyst for polycondensation is preferably present in the reaction system in the second step. Therefore, usually, in the second step, the metal catalyst for [Y] polycondensation is blended in the reaction system. [Y] The metal catalyst for polycondensation may be blended at any time before or during the second step, but is preferably blended after the first step and before the second step. Thus, if the [Y] metal catalyst for polycondensation is added before the second step, it is advantageous in terms of polymerization activity and color tone. However, the metal catalyst for [Y] polycondensation may be blended before, during or after the first step.

Furthermore, [Y] the metal catalyst for polycondensation may be blended in two or more times, in addition to blending the entire amount at one time.
The blending amount of the metal catalyst for [Y] polycondensation is such that at least one metal atom selected from Group 1 and Group 2 of the periodic table contained in the produced thermoplastic polyester of the present invention is as described above. What is necessary is just to adjust so that (content, molar ratio with a titanium atom) may be satisfy | filled.

  [Y] The metal catalyst for polycondensation is usually solid at room temperature. Therefore, it can be supplied as it is, but in order to stabilize the supply amount and reduce the adverse effects such as denaturation due to heat, it can be used in a solvent such as water, [A] 1,4-butanediol, and [B] PAEG. It is preferable to supply after dissolving. The concentration at this time is arbitrary, but the concentration of the metal catalyst for [Y] polycondensation with respect to the whole solution is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.08% by weight. In addition, it is usually 20% by weight or less, preferably 15% by weight or less, and more preferably 10% by weight or less. In particular, when using magnesium acetate as a metal catalyst for [Y] polycondensation, it is preferable to first dissolve in water and then dilute to [A] 1,4-butanediol or the like.

The conditions in the second step are arbitrary as long as the polycondensation reaction can proceed.
The temperature condition is usually 230 ° C. or higher. Further, in the latter stage of polymerization in which the degree of polymerization increases, shear heat generation due to stirring may accompany, and therefore the temperature is usually less than 250 ° C, preferably 245 ° C or less, more preferably 243 ° C or less, paying attention to the set temperature. If the upper limit of this temperature range is exceeded, terminal vinyl groups and terminal COOH groups will increase, resulting in poor hydrolysis resistance and poor thermal stability. Moreover, it is difficult to produce a high degree of polymerization due to unnecessary side reactions.

The pressure condition in the second step is usually a reduced pressure environment. Specifically, it is 10 Torr or less, preferably 3 Torr or less.
Furthermore, the polymerization time is usually 2 to 8 hours.

  By performing the second step, [A] 1,4-butanediol, [B] PAEG, [C] chain branching agent, and [D] bifunctional carboxylic acid and / or [E] lower alkyl A thermoplastic polyester in which an ester is polycondensed can be obtained.

[II-2. Heat stabilizer blending process)
Moreover, in the manufacturing method of the thermoplastic polyester of this invention, a [F] hindered phenol thermal stabilizer is mix | blended with said reaction system (thermal stabilizer mixing | blending process). Furthermore, [G] pentaerythritol tetrakis [3-lauryl-thio-propionate] is also blended into the reaction system as appropriate (additional heat stabilizer blending step).
The blending amount of [F] hindered phenol heat stabilizer and [G] pentaerythritol tetrakis [3-lauryl-thio-propionate] is within the range described above for the content of the heat stabilizer in the thermoplastic polyester of the present invention. The amount to be.
In addition, the above heat stabilizer may be blended in two or more times in addition to blending the entire amount at one time.

  [F] A hindered phenol-based heat stabilizer and a heat stabilizer such as [G] pentaerythritol tetrakis [3-lauryl-thio-propionate] are optional, and before and during the first step. And after the process, and before, during and after the second process. However, in order to disperse the heat stabilizer well in the thermoplastic polyester, it is preferably blended before the second step, and in order to avoid deactivation of the heat stabilizer during the reaction, the step of the first step After that, it is more preferable to mix before the second step.

[II-3. Solid phase polycondensation process)
Furthermore, a solid phase polycondensation step can be performed after the reaction step (that is, after the second step). [C] Although there is a risk of gelation at the time of melt polycondensation due to the blending of the chain branching agent, if the melt polycondensation is stopped at a relatively low molecular weight and then solid-phase polycondensation is performed, the gelation can be removed. It is possible to stably obtain a polymer having a high degree of polymerization while avoiding production risks such as defective production.

  In this case, melt polycondensation is preferably the intrinsic viscosity value determined according to the measurement method described in the examples below, and is stopped at 0.6 to 1.1, and solid phase polycondensation is preferably performed. If the intrinsic viscosity is below the lower limit of the above range, the melt viscosity is too low to make a chip, and if it exceeds the upper limit, the advantage of solid phase polycondensation may not be obtained.

The reaction conditions in the solid phase polycondensation step are arbitrary as long as the solid phase polycondensation reaction proceeds.
However, the temperature condition is the temperature of the thermoplastic polyester, which is usually 170 ° C or higher, preferably 180 ° C or higher, more preferably 185 ° C or higher, and usually 210 ° C or lower, preferably 200 ° C or lower, more preferably 195 ° C or lower. It is. If the temperature is lower than this, polycondensation does not proceed, and if the temperature is higher, the thermoplastic polyester may be fused to the reactor wall surface, which may make it difficult to produce.

[II-4. Other processes]
In addition, other catalysts, reaction aids, various additives (for example, crystal nucleating agents such as titanium oxide and talc used as pigments and matting agents, flame retardants, etc., as long as the properties of the thermoplastic polyester of the present invention are not impaired. , Antistatic agents, mold release agents, ultraviolet absorbers, and the like). The blending time may be any of before, during and after the first step, and before, during and after the second step.

[II-5. (Production efficiency)
According to the method for producing a thermoplastic polyester of the present invention, it is possible to efficiently produce the thermoplastic polyester of the present invention.

[III. (Consideration)
As described above, the thermoplastic polyester of the present invention is excellent in film moldability and residence heat stability, and can be suitably used for high-quality films having no defects such as fish eyes and excellent color tone. . Moreover, according to the method for producing a thermoplastic polyester of the present invention, the thermoplastic polyester of the present invention can be produced with high production efficiency.

The reason why the above-described excellent advantages can be obtained by the present invention is presumed as follows.
[B] By setting the content of the PAEG unit to 5 to 35% by weight, in the film obtained by molding from the thermoplastic polyester of the present invention, it is possible to suppress a decrease in heat resistance and strength of polybutylene terephthalate. In addition, the film can be given flexibility with respect to the hardness which is a drawback of polybutylene terephthalate. On the other hand, in the copolyester described in Patent Document 1, the flexibility is high because the content of PAEG units is too much, but the heat resistance and strength are greatly reduced.

In addition, by blending an appropriate amount of [C] chain branching agent, the thermoplastic polyester of the present invention can have an appropriate melt tension and is excellent in film moldability.
Further, regarding the blending of the reaction catalyst and the heat stabilizer, the present invention has been achieved by optimizing the catalyst type and blending amount, blending time, heat stabilizer amount and kind with respect to the characteristics of the present reaction system.

  Conventionally, in this reaction system, there is a problem that [B] PAEG is easily decomposed during the reaction, and if [X] titanium compound is large, the decomposition reaction is promoted, so a large amount of [F] hindered phenol heat stabilizer is used. It was necessary to blend in. However, the [F] hindered phenol heat stabilizer has a problem that it is easily colored, and a film having a large amount of blend has a problem that the color tone is poor. However, if the [F] hindered phenol heat stabilizer is reduced in order to improve the color tone, the heat stability at the time of molding is lowered. Furthermore, when there are many [X] titanium compounds, the aggregated foreign material generate | occur | produces in the obtained polycondensate, and the subject that a fish eye generate | occur | produces on the film occurred.

  As a result of intensive studies, the present inventors have found that the amount of [F] hindered phenol heat stabilizer can be reduced by suppressing the amount of [X] titanium compound to an appropriate amount. Furthermore, the mixing time of [X] titanium compound is divided into two or more times and combined with the metal catalyst for [Y] polycondensation, the reaction time can be shortened and the production efficiency can be increased. I found.

  In addition, among the [F] hindered phenol heat stabilizers, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is a molten heat stabilizer. It has been found that it has excellent residence heat stability and can suppress a decrease in melt viscosity during film formation. Furthermore, the combined use of [G] pentaerythritol tetrakis [3-lauryl-thio-propionate] allows the amount of [F] hindered phenol heat stabilizer to be reduced while maintaining thermal stability. I found.

On the other hand, in the production method described in Patent Document 1, the amount of [F] hindered phenol-based heat stabilizer is large and the film is colored, and the thermal stability is pentaerythritol tetrakis [3- (3,5-di-t. -Butyl-4-hydroxyphenyl) propionate].
Moreover, in the manufacturing method of patent document 3, since there were many [X] titanium compounds and there were few amounts of [F] hindered phenol type heat stabilizers, thermal stability was inferior and fish eyes increased.
Furthermore, unlike the method of melt polymerization from monomers, the production method described in Patent Document 2 is a method in which a polymer is further reacted, resulting in an increase in the number of production steps and poor production efficiency. Furthermore, the polymerization rate was slow and the productivity was poor as compared with those using the [Y] metal catalyst for polycondensation in combination.

[IV. the film〕
The film of the present invention is a film made of the thermoplastic polyester of the present invention. The specific structure of the film of this invention is arbitrary, and if it is a film formed by containing the thermoplastic polyester of this invention, arbitrary structures can be employ | adopted.
Hereinafter, the example of a preferable structure as a film of this invention is demonstrated.

  For example, when the film of the present invention is a single layer film, it can be produced by a known method using the thermoplastic polyester. Examples of the method for producing the film include molding methods such as sheet molding, T-die molding, air-cooled inflation molding, and water-cooled inflation molding.

  Moreover, when the film of this invention is a laminated | multilayer film, as a film material laminated | stacked on the said thermoplastic polyester, thermoplastic resins other than the said thermoplastic polyester are mentioned, for example. Examples of such thermoplastic resins include thermoplastic polyester resins, ethylene vinyl alcohol copolymer resins, polyamide resins, semi-aromatic polyamide resins, polyvinylidene chloride resins, polyethylene resins, polypropylene resins, ethylene vinyl acetate copolymer resins, polyesters. Resin etc. are mentioned. In addition, these thermoplastic resins may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  As a method for producing a laminated film, for example, a so-called coextrusion method such as coextrusion sheet molding, coextrusion T-die molding, coextrusion air cooling inflation molding, coextrusion water cooling inflation molding, or lamination method after obtaining a single layer film The method of laminating with other films is mentioned.

  The film of the present invention may be a stretched film. The stretched film can also be obtained, for example, by stretching a film-shaped molded product. As the stretching method, a known method can be applied. For example, in the case of a film formed by the T-die method, the roll method can be used for longitudinal stretching. Further, when stretching in the transverse direction, a sequential biaxial stretching method by a tenter method can be used.

The thickness of the film of the present invention is arbitrary, but when it is a single layer film, it is usually about 10 to 300 μm, and when it is a laminated film, the thickness of the thermoplastic polyester layer is usually about 5 to 150 μm. The thickness of the laminated film is usually about 15 to 500 μm. If the film is too thick, the transparency is lowered, and if it is too thin, the pinhole resistance is liable to be lowered.
The film of the present invention can also be used after corona treatment on one or both sides in order to improve printability or laminate properties.
Furthermore, it is preferable that the film forming temperature is usually less than 270 ° C. If it is 270 ° C. or higher, the color tone may deteriorate, the terminal carboxyl group concentration may increase, and the hydrolysis resistance may deteriorate.

  The film made of the thermoplastic polyester of the present invention has a lubricant, a release agent, a heat deterioration inhibitor, an ultraviolet absorber, an antistatic agent, an antiblocking agent, a dye, a pigment, a difficult dye, as long as the effects of the present invention are not impaired. Additives such as flame retardants and spreading agents can be blended. As a method of blending a thermoplastic polyester with a filler and other additives as required, it can be blended in any one of the production processes of a thermoplastic polyester resin, dry blended with a thermoplastic polyester resin after polymerization, or a thermoplastic polyester. It can be carried out according to any blending method such as melt-kneading with a resin or preparing a high-concentration master batch and diluting it for use during molding.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless it deviates from the summary.
In the following description, “1,4-BG” represents 1,4-butanediol, “PTMG # 1000” represents polytetramethylene ether glycol having a molecular weight of 1000, and “DMT” represents dimethyl terephthalate. "TBT" represents tetrabutyl titanate, and "MgOAc" represents magnesium acetate tetrahydrate.

〔Measuring method〕
The measurement methods of physical properties and evaluation items adopted in the following examples are as follows.
(1) Concentrations of titanium, group 1 metal and group 2 metal in thermoplastic table in thermoplastic polyester:
Thermoplastic polyester (hereinafter simply referred to as “polymer”) is wet-decomposed with high-purity sulfuric acid and nitric acid for the electronics industry, and high-resolution ICP (Inductively Coupled Plasma) -MS (Mass Spectrometer) (manufactured by ThermoQuest) is used. And determined as the concentration of titanium atom, group 1 metal atom and group 2 metal atom in the periodic table in the polymer.

(2) Intrinsic viscosity (IV)
Using an Ubbelohde viscometer, the intrinsic viscosity IV of the polymer was determined as follows. That is, using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1), at 30 ° C., the polymer solution having a concentration of 1.0 g / dL and the number of falling seconds of the solvent alone were measured, and obtained from the following formula. .
IV = {(1 + 4K _H η _SP ) ^0.5 −1} / (2K _H C)
(Where η _SP = η / η ₀ −1, η represents the polymer solution falling seconds, η ₀ represents the solvent dropping seconds, C represents the polymer solution concentration (g / dL), K _H represents a constant of Huggins (K _H is 0.33).

(3) Film moldability After 5 kg of polymer was vacuum-dried at 120 ° C. for 8 hours, a molding temperature of 250 ° C., a cooling roll temperature of 80 ° C. using a T-die molding machine (extruder diameter: 40 mm, T-die width: 600 mm) manufactured by Ikegai Co., Ltd. An attempt was made to form a film having a thickness of 30 μm at a take-up speed of 3 m / min. The moldability was evaluated as follows.
Those that were difficult to stably mold, such as severe resin dripping from the die, were marked with ×, and those that could be stably molded were marked with ○.

(4) Fisheye After 5 kg of polymer was vacuum-dried at 120 ° C. for 8 hours, a film forming machine (model ME-20 / 26V2) manufactured by Optical Control Systems was used to obtain a film having a thickness of 50 μm. The cylinder and die temperature was 250 ° C. This film was measured using a Film Quality Testing System [Optical Control Systems, Inc .: Model FS-5], and the number of fish eyes exceeding 200 μm per square meter of the film was measured and determined as follows.
○: Number of fish eyes <20
Δ: Number of fish eyes 20 to 100
×: Number of fish eyes> 100

(5) End face color The film formed by the above "(3) Film formability" is visually observed in a state of being wound around a paper tube. When the film end face is markedly colored, X is slightly colored. The ones that were not colored were marked with ◯.

(6) Stability thermal stability 20 g of polymer was vacuum-dried at 120 ° C. for 10 hours. Capillograph type 1B manufactured by Toyo Seiki Co., Ltd. was dried and filled with polymer, melted and held at a temperature of 245 ° C. for 60 minutes, and then extracted from a capillary with a diameter of 1 mm and L / D = 10 at an extrusion speed of 50 mm / min to obtain a strand. This strand was pelletized with a chip cutter, and the intrinsic viscosity was measured. A value obtained by dividing the intrinsic viscosity after the heat treatment by the intrinsic viscosity before the heating is 0.85 or more, Δ is 0.80 or more and less than 0.85, and x is less than 0.80. It was.

〔material〕
In the following Examples and Comparative Examples, the following substances were used as chain branching agents.
Chain branching agent 1: pentaerythritol.
Chain branching agent 2: trimethylolpropane.
Chain branching agent 3: trimellitic anhydride.

Moreover, the following substances were used as the heat stabilizer.
Stabilizer 1: Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate].
Stabilizer 2: Pentaerythritol tetrakis [3-lauryl-thio-propionate].
Stabilizer 3: 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) benzene.

[Example 1]
33 parts by weight of 1,4-butanediol, 27 parts by weight of polytetramethylene ether glycol having a molecular weight of 1000, 0.17 parts by weight of chain branching agent 1, 64 parts by weight of dimethyl terephthalate, 0.023 parts by weight of tetrabutyl titanate A portion was dissolved in 1,4-butanediol and added, and the temperature was raised from 150 ° C. to 230 ° C. over 3 hours to carry out a transesterification reaction (first step).

  15 minutes before the end of the transesterification reaction, (i) 0.045 parts by weight of stabilizer 1 is added, (ii) 0.045 parts by weight of stabilizer 2 is added, and (iii) 0.018 parts by weight of tetrabutyl titanate. Was dissolved in 1,4-butanediol, and (iv) 0.042 parts by weight of magnesium acetate tetrahydrate dissolved in water was diluted with 1,4-butanediol and added. A polycondensation reaction (second step) was performed.

In the polycondensation reaction, the pressure was gradually reduced from normal pressure to 1 Torr over 85 minutes, and at the same time, the temperature was raised to a predetermined polymerization temperature of 242 ° C., and then continued at a predetermined polymerization temperature of 242 ° C. and 1 Torr to reach a predetermined stirring torque. The reaction was terminated at that point.
The obtained polymer was continuously extracted in a strand shape and cut with a rotary cutter to obtain a polymer chip. The polymerization time at that time and the evaluation results of the obtained polymer are shown in Table 1.

[Examples 2 and 3]
A polymer was obtained in the same manner as in Example 1 except that the amounts of 1,4-butanediol, dimethyl terephthalate and polytetramethylene ether glycol used in Example 1 were changed as shown in Table 1. The polymerization time at that time and the evaluation results of the obtained polymer are shown in Table 1.

[Examples 4 and 5, Comparative Examples 1 and 2]
A polymer was obtained in the same manner as in Example 1 except that the amount of the chain branching agent 1 was changed as shown in Table 1. The polymerization time at that time and the evaluation results of the obtained polymer are shown in Table 1.
In Comparative Example 1, the molten resin was liable to dripping from the die, and stable molding could not be performed. In Comparative Example 2, although the resin pressure was high, molding was possible, but many fish eyes were seen in the film, and the film quality was inferior. As a result of observing the fish eye with an optical microscope, it was considered to be a polymer gel.

[Examples 6 to 10, Comparative Examples 3 to 5]
A polymer was obtained in the same manner as in Example 1 except that the kind and amount of the heat stabilizer were changed as shown in Table 2. Table 2 shows the polymerization time and the evaluation results of the obtained polymer.
In Example 10, the residence heat stability was slightly inferior to Example 1.
In Comparative Example 3, the intrinsic viscosity was greatly reduced when the residence heat stability was evaluated.
In Comparative Example 5, the residence heat stability was poor. In Comparative Example 4 and Comparative Example 6, the film end face was yellowish.

Example 11
A polymer chip was obtained in the same manner as in Example 4 except that the chain branching agent 1 was 0.20 part by weight and the polymerization was stopped by lowering the stirring torque during the polycondensation reaction. The intrinsic viscosity of the polymer after melt polymerization was 1.00.
Next, this polymer chip was subjected to solid phase polycondensation for 6 hours at 190 ° C. under reduced pressure (0.133 kPa or less) in a double conical blender (with an internal volume of 100 L). Table 3 shows the polymerization time and the evaluation results of the polymer after solid phase polycondensation.

Example 12
When the polycondensation reaction is performed, 0.1 part by weight of stabilizer 1 is added 15 minutes before the end of the transesterification reaction, 0.041 part by weight of tetrabutyl titanate, magnesium acetate and tetrahydrate are not added. A polymer was obtained in the same manner as in Example 1 except that 0.042 part by weight of salt was added before the transesterification reaction. Table 3 shows the polymerization time and the evaluation results of the obtained polymer.
As can be seen from Table 3, the polycondensation time was longer in this example than in Example 1.

Example 13
When performing the polycondensation reaction, 0.1 part by weight of stabilizer 1 is added 15 minutes before the end of the transesterification reaction, the stabilizer 2 is not added, and the addition amount of magnesium acetate / tetrahydrate is 0.026 part by weight. A polymer was obtained in the same manner as in Example 1 except that Table 3 shows the polymerization time and the evaluation results of the obtained polymer.
As can be seen from Table 3, the polycondensation time was longer in this example than in Example 1.

Example 14
When performing the polycondensation reaction, 0.1 part by weight of stabilizer 1 is added 15 minutes before the end of the transesterification reaction, and 0.046 part by weight of tetrabutyl titanate is added before the transesterification without adding stabilizer 2. A polymer was obtained in the same manner as in Example 1 except that 0.034 parts by weight of tetrabutyl titanate and 0.079 parts by weight of magnesium acetate tetrahydrate were added 15 minutes before the end of the transesterification reaction. Table 3 shows the polymerization time and the evaluation results of the obtained polymer.
In this example, some fish eyes were observed as compared to Example 1, the film end face was slightly colored, and the residence heat stability was slightly inferior.

Example 15
When the polycondensation reaction is carried out, 0.1 part by weight of stabilizer 1 is added 15 minutes before the end of the transesterification reaction, the amount of tetrabutyl titanate added before the transesterification reaction is not added, and the stabilizer 2 is added. The polymer was obtained in the same manner as in Example 1 except that 031 parts by weight and tetrabutyl titanate and magnesium acetate tetrahydrate were not added 15 minutes before the end of the transesterification reaction. Table 3 shows the polymerization time and the evaluation results of the obtained polymer.
As can be seen from Table 3, in this example, the polycondensation time was longer than that in Example 1, and the polycondensation property was inferior.

[Examples 16 and 17]
A polymer was obtained in the same manner as in Example 1 except that the type of chain branching agent was changed. Table 3 shows the polymerization time and the evaluation results of the obtained polymer.

[Comparative Examples 6 and 7]
A polymer was obtained in the same manner as in Comparative Example 6 with the charging amount as shown in Table 3. Table 3 shows the polymerization time and the evaluation results of the obtained polymer. From Table 3, it can be seen that in these comparative examples, the residence heat stability, fish eye, and end face color are poor and the polycondensation property is poor.

[Summary]
As can be seen from the above examples and comparative examples, the thermoplastic polyester of the present invention is excellent in film moldability and residence heat stability, and is suitable for high-quality films having no defects such as fish eyes and excellent color tone. Can be used.

  The present invention can be used in any industrial field, but is particularly suitable for use in the fields of films, sheets, monofilaments, fibers and the like. Among these, it can be particularly suitably used as a film material.

Claims (18)

[A] 1,4-butanediol,
[B] a polyalkylene ether glycol having a molecular weight of 500 to 6000, and
[C] chain branching agent, and
[D] a bifunctional carboxylic acid based on terephthalic acid and / or a lower alkyl ester of a bifunctional carboxylic acid based on [E] dimethyl terephthalate,
[X] a thermoplastic polyester obtained through a reaction step of reacting in the presence of a titanium compound,
Each component amount satisfies the following conditions (1) to (3),
[F] A thermoplastic polyester comprising 0.01 to 0.4% by weight of a hindered phenol heat stabilizer based on 100% by weight of the thermoplastic polyester.
Condition (1): [B] The proportion of the structural unit derived from polyalkylene ether glycol having a molecular weight of 500 to 6000 with respect to 100% by weight of the thermoplastic polyester is 5 to 35% by weight.
Condition (2): “{(Mole amount of [C] chain branching agent) / ([D] Bifunctional carboxylic acid having terephthalic acid as main component and [E] Bifunctional having dimethyl terephthalate as main component. The molar ratio of the lower alkyl ester of the carboxylic acid)} × 100 ”is 0.05 to 10.
Condition (3): The ratio of titanium atoms to the thermoplastic polyester is 10 ppm to 120 ppm. The thermoplastic polyester according to claim 1, wherein the concentration of titanium atoms in the thermoplastic polyester is 30 ppm to 70 ppm. The thermoplastic polyester according to claim 1 or 2, wherein the thermoplastic polyester contains 5 ppm to 100 ppm of at least one metal atom selected from Groups 1 and 2 of the periodic table. The molar ratio of titanium atoms to at least one metal atom selected from Group 1 and Group 2 of the Periodic Table in the thermoplastic polyester is 0.30 to 1.50. The thermoplastic polyester described. [C] As the chain branching agent, one or more selected from pentaerythritol, trimethylolpropane, trimellitic acid, trimellitic acid trimethyl ester and trimellitic anhydride are blended. The thermoplastic polyester according to claim 1. [C] The thermoplastic polyester according to claim 5, wherein pentaerythritol is blended as a chain branching agent. [F] The hindered phenol heat stabilizer is pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. The thermoplastic polyester as described in any one. [G] Pentaerythritol tetrakis [3-lauryl-thio-propionate] is contained in an amount of 0.4% by weight or less based on 100% by weight of the thermoplastic polyester. The thermoplastic polyester according to item. [A] 1,4-butanediol,
[B] a polyalkylene ether glycol having a molecular weight of 500 to 6000, and
[C] chain branching agent, and
[D] a bifunctional carboxylic acid based on terephthalic acid and / or a lower alkyl ester of a bifunctional carboxylic acid based on [E] dimethyl terephthalate,
[X] A method for producing a thermoplastic polyester having a reaction step of reacting in the presence of a titanium compound,
Each component amount satisfies the following conditions (1) to (3),
[F] A heat stabilizer blending step of blending the hindered phenol-based heat stabilizer so as to contain 0.01 to 0.4% by weight with respect to 100% by weight of the thermoplastic polyester. A method for producing a plastic polyester.
Condition (1): [B] The proportion of the structural unit derived from polyalkylene ether glycol having a molecular weight of 500 to 6000 with respect to 100% by weight of the thermoplastic polyester is 5 to 35% by weight.
Condition (2): “{(Mole amount of [C] chain branching agent) / ([D] Bifunctional carboxylic acid having terephthalic acid as main component and [E] Bifunctional having dimethyl terephthalate as main component. The molar ratio of the lower alkyl ester of the carboxylic acid)} × 100 ”is 0.05 to 10.
Condition (3): The ratio of titanium atoms to the thermoplastic polyester is 10 ppm to 120 ppm. [Y] The method for producing a thermoplastic polyester according to claim 9, wherein the reaction is carried out in the presence of at least one metal compound selected from Groups 1 and 2 of the periodic table. [Y] The [X] titanium compound and the molar ratio of [X] titanium atom to the compound of at least one metal selected from Groups 1 and 2 of the periodic table are 0.30 to 1.50. [Y] The method for producing a thermoplastic polyester according to claim 10, wherein a compound of at least one metal selected from groups 1 and 2 of the periodic table is blended. The reaction step includes a first step in which an esterification reaction or a transesterification reaction proceeds, and a second step in which a melt polycondensation reaction proceeds,
[X] The titanium compound is divided into the first step and the second step and blended,
[Y] The method for producing a thermoplastic polyester according to claim 10 or 11, wherein a compound of at least one metal selected from groups 1 and 2 of the periodic table is blended in the second step. . The method for producing a thermoplastic polyester according to any one of claims 9 to 12, further comprising a solid phase polycondensation step in which a solid phase polycondensation reaction proceeds after the reaction step. [C] As the chain branching agent, one or more selected from pentaerythritol, trimethylolpropane, trimellitic acid, trimellitic acid trimethyl ester, and trimellitic anhydride are blended. A method for producing a thermoplastic polyester according to claim 1. [C] The method for producing a thermoplastic polyester according to claim 14, wherein the chain branching agent is pentaerythritol. [F] The hindered phenol heat stabilizer is pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. The manufacturing method of the thermoplastic polyester as described in any one. [G] An additional heat stabilizer blending step of blending 0.4% by weight or less of pentaerythritol tetrakis [3-lauryl-thio-propionate] with respect to 100% by weight of the thermoplastic polyester, Item 17. A method for producing a thermoplastic polyester according to any one of Items 9 to 16. A film comprising the thermoplastic polyester according to any one of claims 1 to 8.