JPH08127640A - Production of molded article of polyester and molded article of polyester - Google Patents

Abstract

PURPOSE: To obtain a polyester having an extremely low formaldehyde content. CONSTITUTION: A polyester obtained by production processes comprising (A) a liquid-phase polycondensation process for producing a polyester (a) by subjecting a terephthalic acid-containing dicarboxylic acid or its ester derivative and an ethylene glycol-containing dihydroxy compound or its ester derivative to liquid-phase polycondensation in the presence of a polycondensation catalyst and phosphorous acid or its derivative and (B) a solid-phase polycondensation process for producing a polyester (b) having 0.5-1.4dl/g intrinsic viscosity [η]measured in o-chlorophenol by heating the polyester (a) in an inert gas atmosphere at the melting point or below it is molded by injection molding or extrusion molding to provide the objective method for producing a molded article having <=1.8ppm formaldehyde content.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyester molded article and a polyester molded article, and more particularly to a method for producing a polyester molded article having an extremely low formaldehyde content and a polyester molded article.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Bottles obtained by biaxially stretch-molding saturated polyester such as polyethylene terephthalate are excellent in transparency, mechanical strength, heat resistance and gas barrier property, and can be used for juices, soft drinks, carbonated drinks, etc. It is widely used as a beverage filling container (PET bottle).

Such polyesters are obtained by subjecting a dicarboxylic acid or its ester-forming derivative and a dihydroxy compound or its ester-forming derivative to liquid phase polycondensation in the presence of a germanium compound as a polycondensation catalyst, and then solid phase polycondensation. Obtained by condensation. The polyester thus obtained usually contains water in an amount close to 1% in the air, and therefore, after being dried in air or in nitrogen immediately before molding, it is usually formed into various forms by various molding methods. It is formed into an article, such as a bottle or a sheet.

However, the bottle produced using the polyester obtained by the above method usually contains formaldehyde in an amount of about 2 to 10 ppm. In such a bottle having a high formaldehyde content, there is a problem that the taste of the filled contents is significantly deteriorated. Therefore, it is desirable that the formaldehyde content in the polyester for forming the polyester molded product is as low as possible.

In view of the current situation as described above, the present inventors have
As a result of diligent research to reduce the formaldehyde content in the polyester for forming a polyester molded product as much as possible, a specific phosphorus compound was used during the production of polyethylene terephthalate, and the solid phase was used in an inert gas atmosphere with a specific oxygen concentration. The present invention has been completed by finding out that the formaldehyde content in the obtained polyethylene terephthalate can be remarkably reduced by carrying out the polycondensation step.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to provide a method for producing a polyester molded product having an extremely low formaldehyde content.

The object of the present invention is to provide a polyester molding having a very low formaldehyde content.

[0008]

SUMMARY OF THE INVENTION In the first method for producing a polyester molded product according to the present invention, (A) a dicarboxylic acid containing terephthalic acid or an ester derivative thereof and a dihydroxy compound containing ethylene glycol or an ester derivative thereof are polycondensed. A liquid phase polycondensation step of producing a polyester (a) by liquid phase polycondensation in the presence of a catalyst and phosphorous acid or a derivative thereof; and (C) the polyester (a) having a melting point not higher than a melting point in an inert gas atmosphere. When heated to temperature, the intrinsic viscosity [η] measured in o-chlorophenol is 0.5-
The solid phase polycondensation step for producing the polyester (b) in the range of 1.4 dl / g, and the polyester obtained by the production step including injection molding or extrusion molding to give a formaldehyde content of 1. It is characterized by producing a molded product having a content of 8 ppm or less.

In the second method for producing a polyester molded product according to the present invention, as the polyester, after the solid phase polycondensation step (C) as described above, (D-1) the polyester (b) is further cooled to room temperature. Water treatment step of producing polyester (c) by immersing in water of 150 ° C for 1 minute to 20 hours, or (D-2) the polyester (b) at room temperature to
What was obtained by the manufacturing process including the steam treatment process of manufacturing polyester (c) by making it contact with 230 degreeC steam for 1 minute-20 hours is used as polyester for injection molding or extrusion molding.

In the present invention, as the polycondensation catalyst,
Germanium dioxide is preferably used. The injection molding or extrusion molding is preferably performed by melting under an inert gas. In the present invention, prior to the solid-phase polycondensation of the polyester (a), pre-crystallization is carried out by keeping the polyester (a) at a temperature above the elevated temperature crystallization temperature (Tc1) and below the melting point for 1 to 30 minutes. You may perform a process (B).

Further, in the present invention, the content of isophthalic acid in the dicarboxylic acid is in the range of 0 to 10 mol%,
The content of diethylene glycol in the dihydroxy compound is preferably 0 to 10 mol%, and the content of cyclohexanedimethanol is preferably 0 to 10 mol%.

The polyester molded product according to the present invention is obtained by the above-mentioned manufacturing method. The polyester molded product of the present invention can be suitably used as a bottle-forming preform, a bottle, a sheet and the like.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The method for producing a polyester molded article and the polyester molded article according to the present invention will be specifically described below.

In the first method for producing a polyester molded article according to the present invention, (A) a terephthalic acid-containing dicarboxylic acid or an ester derivative thereof and an ethylene glycol-containing dihydroxy compound or an ester derivative thereof,
A liquid-phase polycondensation step of producing a polyester (a) by liquid-phase polycondensation in the presence of a polycondensation catalyst and phosphorous acid or a derivative thereof; and (C) the polyester (a) in an inert gas atmosphere. When heated to a temperature below the melting point, the intrinsic viscosity [η] measured in o-chlorophenol is 0.5 to 1.
A solid phase polycondensation step for producing a polyester (b) in the range of 4 dl / g, and a polyester obtained by a production step comprising: injection molding or extrusion molding,
A molded product having a formaldehyde content of 1.8 ppm or less is produced.

In the present invention, the polyester (a) obtained in the liquid-phase polycondensation step (A) is obtained by subjecting the polyester (a) to a crystallization temperature (Tc1) or higher at a temperature above the crystallization temperature (Tc1) prior to solid-phase polymerization.
In addition, the pre-crystallization step (B) of keeping the temperature below the melting point for 1 to 30 minutes may be performed.

The temperature rising crystallization temperature (Tc1) can be determined as follows. The temperature rise crystallization temperature (Tc1) of polyester is measured by the following method.

That is, Perkin Elmer DSC-
Approximately 5 mmHg at approximately 140 ° C using a type 2 differential scanning calorimeter
A thin piece of a sample of about 10 mg collected from the central portion of a polyester chip dried under the pressure of about 5 hours or more is enclosed in a liquid aluminum pan under a nitrogen atmosphere for measurement.
The measurement conditions are as follows: First, the temperature is raised rapidly from room temperature to 10 at 290 ° C.
After melting and holding for 10 minutes, it is rapidly cooled to room temperature, then 10
The peak temperature of the exothermic peak detected when the temperature is raised at a temperature rising rate of ° C / min is determined.

Each step will be described in detail below. (A) Liquid Phase Polycondensation Step In the present invention, first, in a liquid phase polycondensation step, a dicarboxylic acid containing terephthalic acid or an ester derivative thereof (for example, a lower alkyl ester of dicarboxylic acid, a phenyl ester of dicarboxylic acid, etc.) and ethylene glycol are used. A polyester compound prepared by liquid-phase polycondensation by heating and melting an esterified product of a dihydroxy compound containing OH or its ester derivative (for example, monocarboxylic acid ester ethylene oxide) in the presence of a polycondensation catalyst and phosphorous acid or its derivative. (A) is manufactured.

In the present invention, (polyethylene terephthalate) may be produced using terephthalic acid and ethylene glycol, and a dicarboxylic acid (a) containing terephthalic acid and a dicarboxylic acid other than terephthalic acid, ethylene glycol and ethylene glycol and A copolyester can also be produced using a dihydroxy compound (b) containing a dihydroxy compound other than ethylene glycol.

Specific examples of the dicarboxylic acid other than terephthalic acid used for producing the copolyester include phthalic acid (orthophthalic acid), isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and diphenoxyethanedicarboxylic acid. Aromatic dicarboxylic acid,
Examples thereof include aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and decanedicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and ester derivatives thereof. You may use these in combination of 2 or more types. Of these, isophthalic acid is preferably used.

Specific examples of the dihydroxy compound other than ethylene glycol include diethylene glycol, trimethylene glycol (propylene glycol), tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, diethylene glycol, triethylene glycol, Aliphatic glycols such as tetraethylene glycol and polyethylene glycol, alicyclic glycols such as cyclohexanedimethanol, bisphenols, hydroquinone, aromatic dihydroxy compounds such as 2,2-bis (4-β-hydroxyethoxyphenyl) propane and These ester derivatives etc. are mentioned. These are 2
It may be used in combination of more than one kind. Of these, diethylene glycol and cyclohexanedimethanol are preferably used.

Dicarboxylic acids other than the terephthalic acid are
It is desirable that the dicarboxylic acid is used in an amount of 0 to 10 mol%, preferably 0 to 5 mol%, more preferably 0 to 3 mol%, and the dihydroxy compound other than ethylene glycol is 1 mol%.
It is desirable to use it in an amount of 0 to 10 mol%, preferably 0 to 5 mol%, and more preferably 0 to 3 mol% as 00 mol%.

In the present invention, a small amount of a structural unit derived from a polyfunctional compound such as trimesic acid, pyromellitic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol, for example, 2 mol% or less is used. You may use.

In the liquid phase polycondensation step, the above-mentioned dicarboxylic acid or its ester derivative (hereinafter sometimes referred to simply as "dicarboxylic acid") and dihydroxy compound or its ester derivative (hereinafter simply referred to as "dihydroxy compound"). In this liquid phase polycondensation step, first, a dicarboxylic acid and a dihydroxy compound are usually subjected to an esterification reaction [esterification reaction step (A-1)], Then, a liquid phase polycondensation reaction [polycondensation reaction step (A-2)] is performed.

Specifically, first, a slurry containing a dicarboxylic acid and a dihydroxy compound is prepared. Such a slurry contains 1.02 to 1 mol of dicarboxylic acid.
It contains 2.0 mol, preferably 1.03 to 1.5 mol of dihydroxy compound.

This slurry has an esterification reaction step (A-
It is continuously supplied to 1). The esterification reaction is carried out by removing at least two esterification reactors in series using a device in which the dihydroxy compound is refluxed while removing water or alcohol produced by the reaction from the system in a rectification column. To be done.

The esterification reaction step (A-1) is usually carried out in multiple stages, and the esterification reaction in the first stage is usually at a reaction temperature of 240 to 270 ° C., preferably 245 to 265 ° C. and a pressure of 0.2 to. 3 kg / cm ² G, preferably 0.5-2 k
The esterification reaction at the final stage is usually carried out under the conditions of g / cm ² G and the reaction temperature is usually 250 to 280 ° C., preferably 255 to 275 ° C., and the pressure is 0 to 1.5 kg / cm.
It is carried out under the conditions of ² G, preferably 0 to 1.3 kg / cm ² G.

When the esterification reaction step (A-1) is carried out in three or more stages, from the second stage to the stage immediately before the final stage, the reaction conditions of the first stage and the final stage are used. Performed under conditions between the reaction conditions. For example, when the esterification reaction step is carried out in three stages, the esterification reaction in the second stage usually has a reaction temperature of 245 to 275 ° C., preferably 250 to 2 ° C.
70 ° C., pressure 0 to ² kg / cm ² G, preferably 0.2
It is carried out under the condition of ˜1.5 kg / cm ² G.

The reaction rate of the esterification reaction in each of these stages is not particularly limited, but it is preferable that the degree of increase in the esterification reaction rate in each stage is smoothly distributed, and further, the esterification reaction of the final stage. In the product, it is usually desired to reach 90% or more, preferably 93% or more.

An esterification product (low-order condensate) of a dicarboxylic acid and a dihydroxy compound is obtained by the esterification step (A-1), and the number-average molecular weight of the low-order condensate is usually 500 to 5,000.

Such an esterification reaction can be carried out without adding an additive other than the dicarboxylic acid and the dihydroxy compound, or can be carried out in the coexistence of a polycondensation catalyst described later. In addition, tertiary amines such as trimethylamine, tri-n-butylamine and benzyldimethylamine, quaternary ammonium such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide and trimethylbenzylammonium hydroxide,
It can be carried out by adding a small amount of a basic compound such as lithium carbonate, sodium carbonate, potassium carbonate or sodium acetate. These basic compounds may be added to all of a plurality of esterification reactors connected in series as described above, or may be added to a specific reactor after the first stage or the second stage. May be.

The esterified product thus obtained is
The liquid phase polycondensation reactor is continuously fed. In the liquid phase polycondensation reactor, the polycondensation catalyst is heated under reduced pressure in the presence of a polycondensation catalyst to a temperature equal to or higher than the melting point of the obtained polyester, and the glycol produced at this time is polycondensed while being distilled out of the system.

In the present invention, the polycondensation reaction step (A-2) comprises
It may be carried out in one step or in plural steps. When the polycondensation reaction step is carried out in a plurality of steps, the first-stage polycondensation reaction is usually a reaction temperature of 250 to 290 ° C., preferably 260 to 280 ° C., a pressure of 500 to 20 Torr,
It is preferably carried out under the conditions of 200 to 30 Torr, and the polycondensation reaction in the final stage is usually carried out at a reaction temperature of 265 to 300.
° C, preferably 270-295 ° C, pressure 10-0.1T
orr, preferably 5 to 0.1 Torr, particularly preferably 2 to 0.1 Torr.

When the polycondensation reaction step is carried out in three or more stages, the polycondensation reaction from the second stage to the one stage before the final stage is carried out by the reaction conditions of the first stage and the final stage. It is carried out under conditions in between. For example, the polycondensation reaction step is 3
If carried out in stages, the second stage polycondensation reaction is
Usually, the reaction temperature is 260 to 295 ° C., preferably 270 to
285 ° C., pressure 50 to 2 Torr, preferably 40 to
It is performed under the condition of 5 Torr.

In the present invention, the intrinsic viscosity measured in o-chlorophenol at 25 ° C. in the liquid phase polycondensation step (A) as described above has an intrinsic viscosity of 0.5 to 1.0 dl / g, preferably 0. A polyester (a) of 0.5 to 0.8 dl / g is produced. Although the intrinsic viscosity reached in each stage except the final stage of the liquid phase polycondensation reaction step is not particularly limited, it is preferable that the degree of increase in the intrinsic viscosity in each stage is smoothly distributed.

In this specification, the intrinsic viscosity [η]
Is 1.2 g of polyester and 15 m of o-chlorophenol
Calculated from the solution viscosity measured at 25 ° C. after being dissolved by heating in 1 l, cooled.

The above liquid phase polycondensation reaction is carried out in the presence of a polycondensation catalyst. As the polycondensation catalyst, a germanium compound such as germanium dioxide, germanium tetraethoxide or germanium tetra n-butoxide, an antimony catalyst such as antimony trioxide or a titanium catalyst such as titanium tetrabutoxide can be used.

Of these polycondensation catalysts, it is preferable to use a germanium dioxide compound because a polyester excellent in hue and transparency can be obtained. The polycondensation catalyst as described above is 0.00 in terms of metal weight in the polycondensation catalyst based on the total weight of the dicarboxylic acid and the dihydroxy compound.
05-0.2% by weight, preferably 0.001-0.05
It is desirable to use it in a weight percentage.

The polycondensation reaction is carried out in the coexistence of phosphorous acid or its derivative which serves as a stabilizer. Examples of phosphorous acid derivatives (phosphorous acid derivatives) include triphenyl phosphite, trilauryl phosphite, tridecyl phosphite, triisodecyl phosphite, triisooctyl phosphite, trioctyl phosphite, and trioctadecyl phosphite. , Tristearylphosphite, trisdodecylphosphite, trisnonylphenylphosphite, tris-di-nonylphenylphosphite, tris (2,4-di-tert-butylphenyl) phosphite, trisnonylphenylphosphite, bis ( 2,6-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite and other phosphite esters, dilauryl phosphite, diethyl phosphite, diphenyl phosphite and other phosphite diesters Which is used.

In the present invention, phosphorous acid may be used alone as the phosphorous acid or the derivative of phosphorous acid as described above, and one kind may be selected from the phosphorous acid derivative as described above. May be used alone, or with phosphorous acid and 1
One kind or two or more kinds of phosphorous acid derivatives may be used in combination, or only two kinds of phosphorous acid derivatives may be used in combination.

The phosphorous acid or its derivative as described above is 0.001 to 0.1% by weight, preferably 0.002 to 0.002% by weight in terms of phosphorus atom weight, based on the total weight of the dicarboxylic acid and the dihydroxy compound. It is preferably used in a proportion of 0.02% by weight.

In the present invention, the following "other phosphorus compounds" may be used together with the phosphorous acid or its derivative. Examples of other phosphorus compounds include phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, methyl assid phosphate, isopropyl assid phosphate, butyl. Examples thereof include acid phosphates such as acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate, and phosphorus compounds such as phosphoric acid and polyphosphoric acid.

In the present invention, such "phosphorous acid or its derivative" and "other phosphorus-based compound" (collectively both are also simply referred to as "phosphorus-based compound") mean dicarboxylic acid and dihydroxy compound. 0.0 in terms of the weight of phosphorus atom in the phosphorus compound (stabilizer) with respect to the total weight of
01-0.1% by weight, preferably 0.002-0.02
It is desirable to use it in a weight percentage.

These polycondensation catalysts and phosphorus compounds can be supplied in the esterification step (A-1) as described above, or the first stage reaction of the polycondensation reaction step (A-2). It can also be supplied to the container.

The polyester (a) thus obtained from the final liquid-phase polycondensation reactor is usually formed into particles (chips) by the melt extrusion molding method. (B) Pre-Crystallization Step In the present invention, the polyester (a) thus obtained may be pre-crystallized.

In this pre-crystallization step, the polyester (a) is dried at a temperature between the elevated crystallization temperature (Tc1) and the melting point, preferably 10 ° C. higher than Tc1 and 40 ° C. lower than the melting point. , 1 to 30 minutes, preferably 5 to 20 minutes.

For example, when the polyester is polyethylene terephthalate, specifically, it is 160 to 200.
C., preferably 165 to 190.degree. C. for 1 to 30 minutes.

This pre-crystallization step is carried out in air or in an inert atmosphere, but it is preferably carried out in an inert atmosphere, more preferably in an inert atmosphere having an oxygen concentration of 20 ppm or less. . The oxygen concentration in this specification is measured by a trace oxygen concentration meter.

The pre-crystallized polyester (a) is
It is desirable that the crystallinity is 20 to 50%. In the pre-crystallization step, the so-called solid phase polycondensation reaction of the polyester does not proceed, and the intrinsic viscosity of the pre-crystallized polyester (a) is the same as that of the polyester (a) obtained in the liquid phase polycondensation step (A). It is almost the same as the intrinsic viscosity, and the difference between the intrinsic viscosity of the pre-crystallized polyester (a) and the intrinsic viscosity of the pre-crystallized polyester (a) is usually 0.06d.
It is 1 / g or less.

(C) Solid Phase Polycondensation Step In the present invention, the polyester (a) obtained as described above or the pre-crystallized polyester (a) is subjected to solid phase polycondensation.

In the solid phase polycondensation step, the oxygen concentration is 100 pp.
m or less, preferably 50 ppm or less in an inert gas atmosphere. Examples of the inert gas include nitrogen gas, argon gas, carbon dioxide gas and the like, and among these, nitrogen gas is preferably used.

Such solid phase polycondensation step comprises at least one stage, the polycondensation temperature is usually 190 to 230 ° C., preferably 195 to 225 ° C., and the pressure is usually 1 kg.
/ Cm ² G to 10 Torr, preferably atmospheric pressure to 10
It is carried out under the conditions of 0 Torr.

Polyester (b) thus obtained
The intrinsic viscosity of is usually 0.5 to 1.4 dl / g, preferably 0.6 to 1.3 dl / g. The density of this polyester (b) is usually 1.37 g.
/ Cm ³ or more, preferably 1.38 g / cm ³ or more, more preferably 1.39 g / cm ³ or more.

In the second method for producing a polyester molded product according to the present invention, the polyester (b) obtained through the solid phase polycondensation step as described above is treated with water (D-1) or steam (D). -2) Do.

(D-1) Water Treatment Step The water treatment of the polyester (b) is carried out by bringing the polyester (b) into contact with water. The polyester (b) used here is preferably granular (pellet-like).

The contact between the polyester (b) and water is carried out by subjecting the polyester (b) to room temperature to 150 ° C., preferably 70 to 1
In water at 10 ° C. for 1 minute to 20 hours, preferably 5 minutes to 10
It is performed by soaking for a time.

More specifically, 1 part in water at 50 to 150 ° C.
Minutes to 10 hours, preferably 3 minutes to 70-110 ° C water
It is performed by soaking for 5 hours. When such a water treatment step is carried out, the mold stain during injection molding and the mold stain during blow molding are extremely reduced. This is because when the polyester (b) and water are brought into contact with each other, the polycondensation catalyst contained in the polyester is deactivated, so that the decomposition reaction or the transesterification reaction hardly progresses due to heating during molding, It is considered that the amount of the resulting oligomer such as a cyclic trimer is reduced and the amount of mold stain is reduced.

(D-2) Steam Treatment Step The steam treatment of the polyester (b) is performed by bringing the polyester (b) and steam into contact with each other. The polyester (b) used here is preferably granular (pellet-like).

The contact between the polyester (b) and water vapor is
Polyester (b) is at room temperature to 230 ° C, preferably 70
-150 degreeC, More preferably, it is carried out by making it contact with steam of 90-140 degreeC for 1 minute-20 hours, preferably for 5 minutes-10 hours.

More specifically, steam at 50 to 230 ° C. for 1 minute to 10 hours, preferably steam at 70 to 150 ° C. for 3 minutes to 5 hours, more preferably steam at 90 to 140 ° C. for 3 minutes to It is carried out by contacting for 5 hours.

When such a steam treatment step is carried out, the mold contamination during injection molding or blow molding becomes extremely small. This is because when the polyester (b) and steam are brought into contact with each other, the polycondensation catalyst contained in the polyester is deactivated, so that the decomposition reaction or the transesterification reaction hardly progresses due to heating during molding, Therefore, it is considered that the amount of the oligomers such as the cyclic trimer produced is reduced and the amount of the mold stain is reduced.

Molding of Polyester In the present invention, the solid phase polycondensation step (C) is carried out as described above.
The polyester (c) obtained through the above or, if necessary, the above-mentioned water treatment or steam treatment step is formed into various molded products by various molding methods.

For example, to form a hollow molded article such as a bottle, first, the polyester (c) is used at 120 to 180 ° C., preferably 135 ° C., using air having a dew point of -25 ° C. or lower.
At a temperature of ~ 170 ° C for 2 to 16 hours, preferably 3 to 8
Dry for an hour. Instead of air having a dew point of -25 ° C or less, the amount of impurities such as oxygen is 100 ppm or less, preferably 5
You may dry using 0 ppm or less of inert gas. Examples of the inert gas include those mentioned above, and nitrogen gas is particularly preferable.

Then, the dried polyester (c) was
Molding in an injection molding machine or an extrusion molding machine in a state of being melted under heating in an inert gas to a temperature of not lower than the melting point and not higher than the decomposition temperature, preferably 10 ° C higher than the melting point and lower than 15 ° C lower than the decomposition temperature. It is supplied to a machine to mold a preform for a hollow molded body.

In injection molding, usually, the granular polyester contained in the hopper is supplied from the supply port to the heating cylinder at one end, is melted in the heating cylinder, and is provided on the side opposite to the supply port. A melted polyester is injected from a nozzle into a mold to be molded into a molded product (preform for hollow molded product). In the present invention, it is preferable to melt the polyester in the heating cylinder in an inert gas atmosphere. As the inert gas used at this time, an inert gas having an amount of impurities such as oxygen of 100 ppm or less, preferably 50 ppm or less is used. As the inert gas, nitrogen gas or argon gas is used as in the case of the above drying. , Carbon dioxide gas, etc., and nitrogen gas is preferably used. The formaldehyde content of this preform for hollow molded articles is 1.8 ppm or less. In the present invention, it is preferable that the inside of the hopper is also in an inert gas atmosphere. The oxygen concentration in the inert gas in this hopper is 4
% Or less, preferably 2% or less.

Next, this preform is inserted into a mold having a predetermined shape and stretch blow-molded to mold a hollow molded body. The formaldehyde content of this hollow molded article is 1.8 pp
m or less.

The preform for a hollow molded article produced by the method of the present invention has a very low formaldehyde content in the polyester forming the preform for a hollow molded article, so that the preform material for forming a container for filling beverages is used. Is preferably used as. The hollow molded article produced by the method of the present invention has an extremely low formaldehyde content in the polyester forming the hollow molded article, and does not change the taste of the content so much that the container for filling beverage (PET).
And a preform material for forming the bottle).

When a sheet or the like is molded, it is dried just before molding as described above, and the melted polyester (c) is extruded from a T die using an extruder, for example. The formaldehyde content of this sheet is 1.8 ppm or less.

The sheet produced by the method of the present invention comprises:
Since the formaldehyde content in the polyester forming the sheet is extremely low, it is suitable for use in food packaging and the like.

The polyester molded article of the present invention comprises a dicarboxylic acid containing terephthalic acid or an ester derivative thereof,
After liquid phase polycondensation of a dihydroxy compound containing ethylene glycol or an ester derivative thereof in the presence of a polycondensation catalyst (eg germanium compound) and phosphorous acid or a derivative thereof, and then pre-crystallization as required. Preferably, the intrinsic viscosity [η] measured in o-chlorophenol is 0.5, which is obtained by heating to a temperature below the melting point in an inert gas atmosphere having an oxygen concentration of 100 ppm or less and solid-phase polycondensation. Polyester in the range of ˜1.4 dl / g is preferably dried in air having a dew point of −25 ° C. or lower, or in an inert gas atmosphere, and then preferably melted in an inert gas atmosphere, followed by injection molding or extrusion. It is a molded product formed by molding and has a formaldehyde content of 1.8 ppm or less.

The formaldehyde content of the conventional polyester molding is usually about 2 to 10 ppm,
Thus, there was no polyester molding having an extremely low formaldehyde content. The polyester molded product of the present invention is suitably used particularly for applications such as food packaging.

[0072]

According to the method for producing a polyester molded product according to the present invention, a polyester molded product having an extremely low formaldehyde content can be obtained.

The polyester molded product of the present invention has an extremely low formaldehyde content and is therefore suitable for use in bottle-forming preforms, bottles, sheets and the like.

[0074]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

The formaldehyde content was measured and the transparency of the molded product was evaluated as follows. [Measurement of Formaldehyde Content] Approximately 2 g of a test piece was sampled from a polyester molded product and freeze-ground with a SPEX freeze-grinding machine. 1 g of the obtained polyester powder is put in a vial bottle, 2 ml of distilled water is added, and water and the polyester powder are mixed well. After closing the cap, the vial bottle is heated at 120 ° C. for 1 hour. After heating, cool in ice water,
Transfer the aqueous solution to another vial and add 0.25% 2,4-
0.2 ml of 6N hydrochloric acid solution of dinitrophenylhydrazone
Add 1 ml of hexane and seal tightly. Then, the contents of the vial bottle were stirred to carry out a derivatization reaction, and then the hexane phase was fractionated and measured by a gas chromatograph.

[Evaluation of Transparency] The transparency of the molded product was visually evaluated. The evaluation criteria are as follows.

◯: It was transparent without clouding. X: Cloudiness was observed.

[0078]

Example 1 A dicarboxylic acid and a dihydroxy compound shown in Table 1 were subjected to liquid phase polycondensation in the presence of phosphorous acid and germanium dioxide as a polycondensation catalyst, followed by precrystallization and solid phase polycondensation. Further, it is dried at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or lower to have an intrinsic viscosity [η] of 0.7
1 dl / g polyester was obtained.

Specifically, this polyester was produced as follows. That is, the first, second, third, fourth
Using a continuous polycondensation device in which the fifth reactor is a tank type and the sixth reactor is a biaxial rotary type horizontal reactor, continuous polymerization is carried out by the following operation. Manufactured.

In advance, 3750 parts by weight of the reaction liquid was retained, and the mixture was stirred at 255 ° C. in a nitrogen atmosphere at 1.7 kg / c.
The slurry prepared by mixing 1437 parts by weight of high-purity terephthalic acid and 645 parts by weight of ethylene glycol every hour was continuously supplied to the first reactor maintained under the condition of m ² G, and the first stage An esterification reaction was performed. This first
In the esterification reaction in the first stage, a mixed solution of 203 parts by weight of water and 3 parts by weight of ethylene glycol was distilled off. The first-stage esterification reaction product was controlled so that the average residence time was 2.0 hours, and continuously maintained under stirring at 260 ° C. under the condition of 0.8 kg / cm ² G. Led to the second reactor.

In this reactor 2, a uniform solution of 0.35 parts by weight of germanium dioxide and 32 parts by weight of ethylene glycol was continuously supplied, and 84 parts by weight of water and 7 parts by weight of an hour were continuously supplied. The mixed solution with ethylene glycol was continuously distilled off, and the second-stage esterification reaction was continued. The second esterification reaction product was controlled so that the average residence time was 2.0 hours, and the third reactor was continuously stirred at 265 ° C. and maintained at normal pressure. Led to.

In this third reactor, 1.23 per hour
While a uniform solution in which phosphorous acid of 22 parts by weight and ethylene glycol of 22 parts by weight are mixed is continuously supplied,
A mixed solution of 21 parts by weight of water and 38 parts by weight of ethylene glycol was continuously distilled off every hour, and the esterification reaction in the third step was continued.

The esterification reaction product of the third stage was also controlled so that the average residence time was 2.0 hours, and continuously introduced into the fourth reactor maintained at 70 mmHg at 275 ° C. with stirring. . In the fourth reactor, a mixture of 62 parts by weight of ethylene glycol and 6 parts by weight of water per hour was continuously distilled off to carry out the first stage polycondensation reaction. In addition, the polycondensation reaction product of the first stage was controlled so that the average residence time was 1.0 hour, and was continuously stirred under 28
It was led to a fifth reactor which was maintained at 5 mm Hg at 0 ° C.

In the fifth reactor, a mixed solution of 26 parts by weight of ethylene glycol and 3 parts by weight of water was continuously distilled off to continue the second-stage polycondensation reaction.
The second-stage polycondensation reaction product is controlled so that the average residence time becomes 1.0 hour, and continuously from 282 ° C.
It was introduced into a sixth reactor which was a horizontal twin-screw rotary reaction tank maintained under the conditions of 1.8 mmHg to 2.5 mmHg at 285 ° C.

In this sixth reactor, the reaction solution of 12 parts by weight of ethylene glycol and 1 part by weight of water was distilled off continuously per hour, and the third stage polycondensation reaction was continued.
The third-stage polycondensation reaction product is controlled so that the average residence time is 2.5 hours, and is continuously withdrawn in a strand form outside the reactor by a polyester withdrawing device, and is taken into water. After being immersed and cooled, it was cut into chips by a strand cutter. Intrinsic viscosity (intrinsic viscosity [η]) IV of the polyester obtained by the above liquid phase polymerization in o-chlorophenol measured at 25 ° C. IV
Was 0.57 dl / g, and the content of dioxyethylene terephthalate component was 2.50 mol%.

Further, the polyester obtained by the liquid phase polymerization is dried in a nitrogen atmosphere at about 140 ° C. for about 15 hours and is crystallized (pre-crystallized) in an inert atmosphere (gas type: nitrogen) having an oxygen concentration of 100 ppm or less. ) Was done. The crystallinity of such pre-crystallized polyester is
It was 25%, and the intrinsic viscosity [η] was 0.50.
After performing such pre-crystallization, it was charged in a tower type solid-state polymerization vessel, and the oxygen concentration was 20 ppm under a nitrogen atmosphere of 50 ppm.
Solid phase polycondensation was performed at 5 ° C. and normal pressure for 15 hours. The intrinsic viscosity of the polyester thus obtained measured in o-chlorophenol at 25 ° C. is 0.80 dl / g,
The density is 1.40 g / cm ³ and the water content is 0.
It was 005%.

5 kg of the polyethylene terephthalate (A) thus obtained was placed in a stainless steel container for 6.5 kg.
It was immersed in kg distilled water. Next, a stainless steel container containing polyethylene terephthalate and distilled water was externally heated, the internal temperature was controlled at 90 ° C., and the content was kept for 4 hours for water treatment.

Then, air having a dew point of -25 ° C or lower was dried at a temperature of 150 ° C for 4 hours to obtain a polyester having an intrinsic viscosity [η] of 0.71 dl / g. The polyester dried in this manner was used as an injection molding machine, M100A manufactured by Meiki Seisakusho Co., Ltd., at a set temperature of 275.
A bottle-forming preform (outer diameter of the mouth portion: 28 mmφ) was molded under the conditions of ° C and a mold temperature of 10 ° C. At this time, the hopper of the injection molding machine was in a dry air atmosphere.

The formaldehyde content of the preform for hollow molded body thus obtained was 1.6 ppm. The transparency of the obtained preform was good (○), the amount of germanium of the test piece taken from the mouth of the preform was 55 ppm, the amount of phosphorus was 40 ppm, the formaldehyde content was 1.6 ppm. there were.

The conditions and results are also shown in Table 1.

[0091]

Example 2 Tris (2,4-di-tert-butylphenyl) phosphite, which uses the dicarboxylic acid and dihydroxy compound shown in Table 1 in place of phosphorous acid in Example 1, and polycondensation Liquid phase polycondensation was carried out in the presence of germanium dioxide as a catalyst in the same manner as in Example 1, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or lower. Thus, a polyester having an intrinsic viscosity [η] of 0.70 dl / g was obtained.

Using the obtained polyester, a preform for forming a bottle (outer diameter of the mouth portion: 28 m) was prepared in the same manner as in Example 1.
mφ) was molded. The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40.
ppm, formaldehyde content is 1.4 ppm
Met.

The conditions and results are also shown in Table 1.

[0094]

Example 3 In Example 1, the dicarboxylic acid and dihydroxy compound shown in Table 1 were used in the presence of triisooctyl phosphite used in place of phosphorous acid and germanium dioxide as a polycondensation catalyst. Liquid phase polycondensation in the same manner as 1, followed by pre-crystallization, solid phase polycondensation,
Further, it was dried at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or lower to obtain a polyester having an intrinsic viscosity [η] of 0.71 dl / g.

Using the obtained polyester, a preform for forming a bottle (outer diameter of the mouth portion: 28 m) was prepared in the same manner as in Example 1.
mφ) was molded. The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40.
ppm, the formaldehyde content is 1.8 ppm
Met.

The conditions and the results are also shown in Table 1.

[0097]

Example 4 In Example 1, the dicarboxylic acid and the dihydroxy compound shown in Table 1 were used, and triphenyl phosphite used in place of phosphorous acid and germanium dioxide as a polycondensation catalyst were used. Liquid phase polycondensation in the same manner as above, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or less to obtain an intrinsic viscosity [η] of 0.71 dl / g of polyester was obtained.

Using the polyester obtained, in the same manner as in Example 1, a bottle forming preform (mouth outer diameter: 28 m)
mφ) was molded. The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40.
ppm, formaldehyde content is 1.3 ppm
Met.

The conditions and the results are also shown in Table 1.

[0100]

Example 5 In Example 1, the dicarboxylic acid and dihydroxy compound shown in Table 1 were used, and tris (2,4-di-tert-butylphenyl) phosphite was used instead of phosphorous acid, and a polycondensation catalyst. Liquid phase polycondensation in the presence of germanium dioxide, which is the same as in Example 1, followed by precrystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in air with a dew point of −25 ° C. or lower. The intrinsic viscosity [η] is 0.
70 dl / g polyester was obtained.

Using the polyester obtained, the inside of the hopper was set to a nitrogen atmosphere having an oxygen concentration of 5 ppm or less, and a bottle-forming preform (outer diameter of the mouth portion: 28 mmφ) was molded.

The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40 p.
pm and the formaldehyde content was 0.6 ppm.

The conditions and results are also shown in Table 1.

[0104]

Example 6 In Example 1, the dicarboxylic acid and dihydroxy compound shown in Table 1 were used, and tris (2,4-di-tert-butylphenyl) phosphite was used instead of phosphorous acid, and a polycondensation catalyst. Liquid phase polycondensation in the presence of germanium dioxide, which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in a nitrogen atmosphere (oxygen concentration; 10 ppm). Thus, a polyester having an intrinsic viscosity [η] of 0.70 dl / g was obtained.

Using the polyester obtained, the inside of the hopper was set to a nitrogen atmosphere having an oxygen concentration of 5 ppm or less, and a bottle-forming preform (outer diameter of the mouth portion: 28 mmφ) was molded. The transparency of the obtained preform was good (○), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, the amount of phosphorus was 40 ppm, and the formaldehyde content was 0.2 ppm. It was

The conditions and results are also shown in Table 1.

[0107]

Example 7 Tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid using the dicarboxylic acid and dihydroxy compound shown in Table 1 in Example 1 and polycondensation catalyst Liquid phase polycondensation in the presence of germanium dioxide, which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in an air atmosphere having a dew point of −25 ° C. or lower. Thus, a polyester having an intrinsic viscosity [η] of 0.70 dl / g was obtained.

A preform for forming a bottle (outer diameter of the mouth portion; 28 m) was prepared by using the obtained polyester in the same manner as in Example 1.
mφ) was molded. Molded preform has 1 mouth
After immersing in silicon oil at 80 ° C. for 5 minutes for crystallization, a 1.5 liter bottle was molded. As the molding machine, Corpoplast LB01 was used, and molding was performed under the conditions of heat setting at a stretching temperature of 105 ° C. and a mold temperature of 130 ° C.

The transparency of the obtained bottle was good (◯), the amount of germanium in the test piece taken from the body of the bottle was 55 ppm, the amount of phosphorus was 40 ppm, the formaldehyde content was 1.4 ppm. there were.

The conditions and the results are also shown in Table 1.

[0111]

Example 8 Tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid using the dicarboxylic acid and dihydroxy compound shown in Table 1 in Example 1 and polycondensation catalyst Liquid phase polycondensation in the presence of germanium dioxide, which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or lower. As a result, a polyester having an intrinsic viscosity [η] of 0.65 dl / g was obtained.

A sheet (thickness: 0.6 mm) was molded using the obtained polyester. Molding machine is Hitachi 50mm
Using φ, molding was performed under the condition of a preset temperature of 275 ° C. At this time, the hopper was in a dry air atmosphere.

The transparency of the obtained sheet was good (◯), the amount of germanium in the test piece taken from the mouth of the sheet was 55 ppm, the amount of phosphorus was 40 ppm, the formaldehyde content was 1.5 ppm. there were.

The conditions and the results are also shown in Table 1.

[0115]

[Table 1]

[0116]

Comparative Example 1 In Example 1, the dicarboxylic acid and the dihydroxy compound shown in Table 2 were used, and in the presence of methyl acid phosphate used in place of phosphorous acid and germanium dioxide as a polycondensation catalyst. Liquid phase polycondensation in the same manner as above, followed by pre-crystallization, solid phase polycondensation, and further drying at 150 ° C. for 4 hours in an air atmosphere to obtain a polyester having an intrinsic viscosity [η] of 0.70 dl / g. .

Using the polyester thus obtained, a bottle forming preform (outer diameter of the mouth portion; 28) was prepared in the same manner as in Example 1.
mmφ) was molded. At this time, the hopper was placed in a dry air atmosphere.

The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40 p.
pm, and the formaldehyde content was 3.1 ppm.

The conditions and results are also shown in Table 2.

[0120]

[Comparative Example 2] The same as Example 1 except that the dicarboxylic acid and dihydroxy compound shown in Table 2 were used in the presence of phosphoric acid used in place of phosphorous acid and germanium dioxide as a polycondensation catalyst. Liquid phase polycondensation, then pre-crystallization, solid phase polycondensation, and further at 150 ° C. for 4 hours,
When dried in an air atmosphere, the intrinsic viscosity [η] is 0.70 dl /
g of polyester was obtained.

Using the polyester obtained, in the same manner as in Example 1, a preform for forming a bottle (outer diameter of the mouth portion; 28
mmφ) was molded. At this time, the hopper was placed in a dry air atmosphere.

The transparency of the obtained preform was good (◯), the amount of germanium in the test piece taken from the mouth of the preform was 55 ppm, and the amount of phosphorus was 40 p.
pm, and the formaldehyde content was 2.9 ppm.

The conditions and results are also shown in Table 2.

[0124]

[Table 2]

[0125]

Example 9 Tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid using the dicarboxylic acid and dihydroxy compound shown in Table 3 in Example 1 and polycondensation catalyst Liquid phase polycondensation in the presence of germanium dioxide which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and holding in distilled water controlled at 90 ° C. for 4 hours for water treatment. . Further 150
The polyester was dried at 4 ° C. for 4 hours with air having a dew point of −25 ° C. or lower to obtain a polyester having an intrinsic viscosity [η] of 0.70 dl / g.

A preform for forming a bottle (outer diameter of the mouth portion: 28) was obtained using the obtained polyester in the same manner as in Example 1.
mmφ) was molded. The formed preform was crystallized by immersing the mouth in silicon oil at 180 ° C. for 5 minutes and then forming a 1.5-liter bottle. Corpoplast LB01 was used as the molding machine, and the stretching temperature was 105 ° C.
Then, molding was performed under the conditions of heat setting at a mold temperature of 130 ° C.

The transparency of the obtained bottle was evaluated. The amount of germanium in the test piece of the bottle body was 55 ppm,
The phosphorus content was 40 ppm and the formaldehyde content was 1.6 ppm.

The conditions and results are also shown in Table 3.

[0129]

Example 10 In Example 1, the dicarboxylic acid and the dihydroxy compound shown in Table 3 were used, and tris (2,4-di-tert-butylphenyl) phosphite was used instead of phosphorous acid, and a polycondensation catalyst. Liquid phase polycondensation in the presence of germanium dioxide which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and holding in distilled water controlled at 90 ° C. for 4 hours for water treatment. . Further 15
The polyester was dried at 0 ° C. for 4 hours in air having a dew point of −25 ° C. or lower to obtain a polyester having an intrinsic viscosity [η] of 0.70 dl / g.

Using the polyester thus obtained, a preform for forming a bottle (outer diameter of mouth: 28) was prepared in the same manner as in Example 1.
mmφ) was molded. The transparency of the obtained preform was evaluated. The germanium content of the preform specimen is 5
The amount of phosphorus was 5 ppm, the amount of phosphorus was 40 ppm, and the formaldehyde content was 1.7 ppm.

The conditions and the results are also shown in Table 3.

[0132]

Example 11 Tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid by using the dicarboxylic acid and dihydroxy compound shown in Table 3 in Example 1 and polycondensation catalyst Liquid-phase polycondensation in the presence of germanium dioxide as in Example 1, followed by pre-crystallization, solid-phase polycondensation, and further at 150 ° C. for 4 hours,
The polyester was dried with air having a dew point of -25 ° C or lower to obtain a polyester having an intrinsic viscosity [η] of 0.70 dl / g.

Using the polyester thus obtained, a preform for forming a bottle (outer diameter of mouth: 28) was prepared in the same manner as in Example 1.
mmφ) was molded. The transparency of the obtained preform was evaluated. The germanium content of the preform specimen is 5
It was 5 ppm, the phosphorus content was 40 ppm, and the formaldehyde content was 1.5 ppm.

The conditions and results are also shown in Table 3.

[0135]

[Example 12] The dicarboxylic acid and dihydroxy compound shown in Table 3 were used in Example 1, and 1.23 per hour was used.
0.7 parts by weight of tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid by weight, 0.5 parts by weight of phosphorous acid per hour, and a polycondensation catalyst. Liquid phase polycondensation in the presence of germanium dioxide as in Example 1, followed by pre-crystallization and solid phase polycondensation,
Water treatment was carried out by holding in distilled water controlled at 90 ° C for 4 hours. 4 hours at 150 ° C, dew point -25
The intrinsic viscosity [η] is 0.71dl after drying in air below ℃
/ G of polyester was obtained.

Using the polyester thus obtained, a preform for forming a bottle (outer diameter of mouth: 28) was prepared in the same manner as in Example 1.
mmφ) was molded. The transparency of the obtained preform was evaluated. The germanium content of the preform specimen is 5
It was 5 ppm, the amount of phosphorus was 35 ppm, and the formaldehyde content was 1.6 ppm.

The conditions and results are also shown in Table 3.

[0138]

[Example 13] The dicarboxylic acid and dihydroxy compound shown in Table 3 were used in Example 1, and 1.23 per hour was used.
0.9 parts by weight of tris (2,4-di-tert-butylphenyl) phosphite used in place of phosphorous acid by weight and 0.5 parts by weight of methyl assidphosphite, and a polycondensation catalyst Liquid phase polycondensation in the presence of germanium dioxide which is the same as in Example 1, followed by pre-crystallization, solid phase polycondensation, and holding in distilled water controlled at 90 ° C. for 4 hours for water treatment. . Further, it was dried at 150 ° C. for 4 hours in air having a dew point of −25 ° C. or lower to obtain a polyester having an intrinsic viscosity [η] of 0.71 dl / g.

Using the polyester thus obtained, a preform for forming a bottle (outer diameter of the mouth portion: 28) was prepared in the same manner as in Example 1.
mmφ) was molded. The transparency of the obtained preform was evaluated. The germanium content of the preform specimen is 5
It was 5 ppm, the phosphorus content was 43 ppm, and the formaldehyde content was 1.5 ppm.

The conditions and results are also shown in Table 3.

[0141]

Example 14 The procedure of Example 1 was repeated except that the dicarboxylic acid and dihydroxy compound shown in Table 3 were used in the presence of methyl assid phosphite used in place of phosphorous acid and germanium dioxide as a polycondensation catalyst. Liquid phase polycondensation in the same manner as 1, followed by pre-crystallization, solid phase polycondensation,
Water treatment was carried out by holding in distilled water controlled at 90 ° C for 4 hours. 4 hours at 150 ° C, dew point -25
Dry with air below ℃, the intrinsic viscosity [η] is 0.70dl
/ G of polyester was obtained.

To 100 parts by weight of the obtained polyester was added bis (2,6-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite.
05 parts by weight were dry blended, and a preform for forming a bottle (outer diameter of the mouth portion: 28 mmφ) was molded in the same manner as in Example 1.

The transparency of the obtained preform was evaluated. The germanium content of the preform test piece is 55 pp
m, the phosphorus content was 65 ppm, and the formaldehyde content was 1.6 ppm.

The conditions and results are also shown in Table 3.

[0145]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // C08L 67:00

Claims (14)

[Claims] 1. A liquid phase gravity of (A) a dicarboxylic acid containing terephthalic acid or an ester derivative thereof and a dihydroxy compound containing ethylene glycol or an ester derivative thereof in the presence of a polycondensation catalyst and phosphorous acid or its derivative. Liquid phase polycondensation step of producing polyester (a) by condensation, and (C) the polyester (a) is heated to a temperature below its melting point in an inert gas atmosphere and measured in o-chlorophenol Intrinsic viscosity [η] is 0.5 to 1.4
The solid phase polycondensation step of producing the polyester (b) in the range of dl / g, and the polyester obtained by the production step including injection molding or extrusion molding to give a formaldehyde content of 1.8 ppm or less. A method for producing a polyester molded article, characterized in that the molded article is produced. 2. The method according to claim 1, wherein the polycondensation catalyst is a germanium compound. 3. The polyester further comprises (D-1) the polyester (b) in water at room temperature to 150 ° C. for 1 minute to
Water treatment step of producing polyester (c) by immersion for 20 hours, or (D-2) Production of polyester (c) by contacting the polyester (b) with water vapor at room temperature to 230 ° C for 1 minute to 20 hours. The method according to claim 1 or 2, wherein the method is obtained by a manufacturing process including a steam treatment step of: 4. The polyester is molded by a step of (E) drying for removing moisture immediately before injection molding or extrusion molding of the polyester (b) or the polyester (c). Item 4. The method according to any one of Items 1 to 3. 5. A liquid phase weight of (A) a dicarboxylic acid containing terephthalic acid or an ester derivative thereof and a dihydroxy compound containing ethylene glycol or an ester derivative thereof in the presence of a polycondensation catalyst and phosphorous acid or its derivative. A liquid phase polycondensation step of producing a polyester (a) by condensation, and (B) the polyester (a) at a temperature above the temperature rising crystallization temperature (Tc1) and below the melting point of 1 to 1.
Preliminary crystallization step of holding for 30 minutes, and (C) The polyester (a) which has undergone the precrystallization step is heated to a temperature below its melting point under an inert gas atmosphere to be measured in o-chlorophenol. A solid phase polycondensation step of producing a polyester (b) having a viscosity [η] in the range of 0.5 to 1.4 dl / g;
After melting under inert gas, molded by injection molding or extrusion molding, the formaldehyde content is 1.8ppm
A method for producing a polyester molded article, which comprises producing the following molded article. 6. The polyester further comprises (D-1) the polyester (b) in water at room temperature to 150 ° C. for 1 minute to
Water treatment step of producing polyester (c) by immersion for 20 hours, or (D-2) Production of polyester (c) by contacting the polyester (b) with water vapor at room temperature to 230 ° C for 1 minute to 20 hours. The method according to claim 5, which is obtained by a manufacturing process including a steam treatment step of: 7. The polyester is produced through a step (E) of drying the polyester (b) or the polyester (c) immediately before injection molding or extrusion molding to remove water. Claims 5-6
The method described in any one of. 8. The method according to claim 1, wherein the injection molding or the extrusion molding of the polyester (b) or the polyester (c) is performed by melting in an inert gas atmosphere. . 9. The solid phase polycondensation step is carried out at an oxygen concentration of 100 pp.
The method according to claim 1, wherein the method is performed in an atmosphere of an inert gas of m or less. 10. The content of isophthalic acid in the dicarboxylic acid is in the range of 0 to 10 mol%, the content of diethylene glycol in the dihydroxy compound is 0 to 10 mol%, and the content of cyclohexanedimethanol is 0-1
The method according to any one of claims 1 to 9, which is in the range of 0 mol%. 11. A polyester molded article obtained by the method according to any one of claims 1 to 10. 12. The polyester molded product according to claim 11, wherein the molded product is a bottle-forming preform. 13. The molded article is a bottle.
The molded polyester article according to item 1. 14. The molded article is a sheet.
The molded polyester article according to item 1.