JP2000219726A - Polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin which has a high transparency and heat- resistant dimensional stability and is useful as vessels or package materials for food supplies, drinks, etc. SOLUTION: A polyester resin wherein the main repeating unit is ethylene terephthalate, is prepared using an antimony compound and a titanium compound and/or a germanium compound as catalysts. Here, a non-crystalline molded product obtained by molding the polyester resin has (a) a density of 1.338 (g/cm3) or smaller when the non-crystalline molded product is heated at 140 deg.C for 60 sec and a density-increase rate at 140 deg.C within the range of from 0.2×10-3 to 0.6×10-3 [g/(cm3.sec)] and (b) a density of 1.338 (g/cm3) or smaller when the non-crystalline molded product is heated at 180 deg.C for 20 sec and a density-increase rate at 180 deg.C within the range of from 0.8×10-3 to 3.0×10-3 [g/(cm3.sec)].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester resin used for molded articles such as bottles, films, sheets and the like. More specifically, the present invention relates to a molded article having excellent transparency and heat-resistant dimensional stability, particularly to a polyester resin which gives a hollow molded article.

[0002]

2. Description of the Related Art Polyester resins, especially polyethylene terephthalate (hereinafter abbreviated as "PET") are characterized by their excellent transparency, mechanical strength, heat resistance, gas barrier properties, and other properties. It is used as a material for containers such as water and mineral water, and its use has been remarkable.

[0003] PET generally used for such applications
Is produced mainly using terephthalic acid and ethylene glycol as raw materials, and using a germanium compound, an antimony compound, a titanium compound and a mixture thereof as a polycondensation catalyst.

Among the above-mentioned catalysts, antimony catalysts are used as catalysts for producing PET for fibers and films because of their low cost. However, compared to the case where a germanium compound or a titanium compound is used as a catalyst, the crystallization rate of the obtained PET is high, and it is very difficult to obtain a hollow molded article having excellent transparency.

In order to solve these problems, a germanium compound or a mixture of the compound and a titanium compound is used as a polycondensation catalyst. However, if an expensive germanium compound is used, the cost of PET becomes high.

As a method for solving such a problem,
For example, JP-A-6-279579 discloses a method in which the transparency is improved by regulating the ratio of the antimony compound to the phosphorus compound. However, the transparency of the hollow molded article made of PET obtained by this method is not sufficient.

Japanese Patent Laid-Open Publication No. Hei 10-36495 discloses a continuous process for producing a polyester having excellent transparency using antimony trioxide, phosphoric acid and a sulfonic acid compound. However, the polyester obtained by such a method has a problem in that the heat stability is poor and the acetaldehyde content of the obtained hollow molded article is high.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves such a problem and provides a molded article having excellent transparency.
An object is to provide an inexpensive polyester resin.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.
That is, the polyester resin of the present invention is a polyester resin in which a main repeating unit produced by using an antimony compound and a titanium compound or / and a germanium compound as a catalyst is ethylene terephthalate,
(A) an amorphous molded article molded from the polyester resin,
The density when heated at 140 ° C. for 60 seconds is 1.338 (g)
/ Cm ³ ) or less and the density increasing rate at 140 ° C. is 0.2 × 10 ^{−3 to} 0.6 × 10 ⁻³ (g / (cm ³
Seconds)) and (b) the amorphous compact
The density when heated at 80 ° C. for 20 seconds is 1.338 (g / g).
cm ³ ) or less and the density increasing rate at 180 ° C. is 0.
A polyester resin characterized by being in the range of 8 × 10 ^{−3 to} 3.0 × 10 ⁻³ (g / (cm ³ · second)).
The polyester resin having the above properties gives a molded article excellent in transparency and heat resistance dimensional stability, particularly a hollow molded article.

In this case, the limiting viscosity is 0.70 to 0.70.
0.90 dl / g, the amount of copolymerized DEG is glycol
1.5-5.0 mol% of the components and a density of 1.37 g /
cm ^ThreeThat is all.

In this case, the content of acetaldehyde can be 10 ppm or less, and the content of cyclic trimer can be 0.35% by weight or less. In this case, the polyester resin may be for a hollow molded article.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polyester resin having a main repeating unit of ethylene terephthalate in the present invention is a linear polyester resin containing at least 85 mol% of ethylene terephthalate units, preferably at most 90 mol%, more preferably at least 95 mol%. It is a linear polyester resin.

The dicarboxylic acids used for copolymerization of the polyester resin include aromatic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid and diphenoxyethanedicarboxylic acid. Dicarboxylic acids and their functional derivatives, p-oxybenzoic acid, oxyacids such as oxycaproic acid and their functional derivatives, adipic acid, sebacic acid, succinic acid, aliphatic dicarboxylic acids such as glutaric acid and their functional derivatives, Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and functional derivatives thereof;

Glycols used for copolymerization of the polyester resin include aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, and alicyclic groups such as cyclohexanedimethanol. And aromatic glycols such as glycol, bisphenol A and alkylene oxide adducts of bisphenol A.

Further, other copolymerizable components comprising a polyfunctional compound in the polyester resin include trimellitic acid and pyromellitic acid as acid components, and glycerin and pentaerythritol as glycol components. Can be mentioned. The amount of the copolymerization component composed of these polyfunctional compounds must be such that the polyester resin maintains a substantially linear shape.

[0016] The polyester resin of the present invention comprises antimony.
Compound and titanium compound and / or germanium compound
Ethylene is the main repeating unit produced using
Polyester resin which is terephthalate,
(A) an amorphous molded article molded from the polyester resin,
The density when heated at 140 ° C. for 60 seconds is 1.338 (g)
/ Cm^Three) Or less, preferably 1.337 (g / cm^Three)
Lower, more preferably 1.336 (g / cm^Three)Less than
And the density increasing rate at 140 ° C. is 0.2 × 10^{- Three}~
0.6 × 10^-3(G / (cm^ThreeSecond)), preferably good
Preferably 0.25 × 10^-3~ 0.55 × 10^-3(G /
(Cm^ThreeSecond)), more preferably 0.30 × 10^-3
~ 0.50 × 10^-3(G / (cm^Three・ Seconds))
And (b) the amorphous compact at 180 ° C. for 20 seconds.
The density when heated is 1.338 (g / cm ^Three) Below, good
Preferably 1.337 (g / cm^Three) Or less, more preferably
Is 1.336 (g / cm^Three) Below and at 180 ° C
Density rise rate is 0.8 × 10^-3~ 3.0 × 10^-3(G /
(Cm^ThreeSecond)), preferably 0.9 × 10^-3~ 2.5
× 10^{- Three}(G / (cm^ThreeSecond)), and more preferably 1.
0x10^-3~ 2.0 × 10^-3(G / (cm^Three・ Seconds))
It is a polyester resin characterized by being within the range.

The density when heated at 140 ° C. for 60 seconds is 1.338 (g / cm ³ ) or more, and the density rise rate at 140 ° C. is 0.6 × 10 ⁻³ (g / (cm ³ · second). )) And the density when heated at 180 ° C. for 20 seconds is 1.
When the density is 338 (g / cm ³ ) or more and the density increase rate at 180 ° C. is 3.0 × 10 ⁻³ (g / (cm ³ · second)) or more, the obtained molded product, particularly, stretch molding Transparency of the body becomes very poor. 0.2 × 1 density increase rate at 140 ° C.
0 ^-3 (g / (cm ³ · sec)) or less and the density increasing rate at 180 ° C. is 0.8 × 10 ⁻³ (g / (cm ³ · sec))
In the following cases, the heat resistance of the obtained molded product deteriorates.

The polyester resin of the present invention is a terephthalate
A direct esterification method in which water is distilled off and esterified by directly reacting the acid with ethylene glycol and / or the third component, followed by polycondensation under reduced pressure, or dimethyl terephthalate and ethylene glycol And / or transesterification by removing the methyl alcohol by reacting the third component and subjecting the mixture to transesterification, followed by transesterification in which polycondensation is performed under reduced pressure. In this production process, a Mg compound, a Ca compound, At least one metal compound selected from a Co compound, a Mn compound and a Zn compound and a P compound are added in two or more portions, and the polycondensation reaction is performed after the esterification or transesterification is substantially completed. Before, Sb compound and T
It can be obtained by performing polycondensation by adding an i compound or a / Ge compound.

Further, solid-state polymerization may be performed to increase the molecular weight of the polyester resin and reduce the acetaldehyde content.

The above-mentioned esterification reaction, transesterification reaction, melt polycondensation reaction and solid phase polymerization reaction may be carried out in a batch reactor or in a continuous reactor.

As the Mg compound, Ca compound, Co compound, Mn compound and Zn compound used in the present invention, any compounds can be used as long as they are soluble in the reaction system.

Examples of the Mg compound include magnesium hydride, magnesium oxide, lower fatty acid salts such as magnesium acetate, and alkoxides such as magnesium methoxide. Examples of the Ca compound include lower fatty acid salts such as calcium hydride, calcium hydroxide and calcium acetate, and alkoxides such as calcium methoxide.

Examples of the Co compound include lower fatty acid salts such as cobalt acetate, organic acid salts such as cobalt naphthenate and cobalt benzoate, chlorides such as cobalt chloride, and cobalt acetylacetonate.

Examples of the Mn compound include organic acid salts such as manganese acetate and manganese benzoate; chlorides such as manganese chloride;
Alkoxides such as manganese methoxide, manganese acetylacetonate and the like can be mentioned.

Examples of the Zn compound include organic acid salts such as zinc acetate and zinc benzoate, chlorides such as zinc chloride, alkoxides such as zinc methoxide, and zinc acetylacetonate.

The P compound used in the present invention includes phosphoric acid, phosphorous acid, phosphonic acid and derivatives thereof. Specific examples include phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, monobutyl phosphate, dibutyl phosphate, and dibutyl phosphate. Phosphoric acid, trimethyl phosphite, triethyl phosphite, tributyl phosphite, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester,
Phenylphosphonic acid diphenyl ester and the like,
These may be used alone or in combination of two or more.

The Sb compound used in the present invention includes:
Examples include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony. Ti used in the present invention
Compounds include tetraethyl titanate, tetraisopropyl titanate, and tetra-n-propyl titanate.
Tetraalkyl titanates such as tetra-n-butyl titanate and their partial hydrolysates, titanyl oxalate, titanyl ammonium oxalate, sodium titanyl oxalate, potassium titanyl oxalate, calcium titanyl oxalate,
Titanyl oxalate compounds such as strontium titanyl oxalate,
Examples thereof include titanium trimellitate, titanium sulfate, and titanium chloride.

The Ge compound used in the present invention includes:
Examples include amorphous germanium dioxide, crystalline germanium dioxide, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite. Mg compound, Ca compound, Co compound, Mn compound and Zn used in the present invention
The compound has at least two components during the production of the polyester resin.
It is preferable to add it in divided portions or more, and the content in the produced polymer is 0.1% in the polymer-1 ton as a metal atom.
It is added so as to be in a range of 1 to 5.0 mol.

The P compound used in the present invention is preferably added at least twice in the course of the production of the polyester resin. Further, the Mg compound and the Ca compound in the polymer with respect to the P atom in the produced polymer are added. , Co compound, Mn compound and Zn compound in a total metal atom ratio of 0.1 to 3.0.

Mg compound, Ca compound, Co compound, M
The method of adding the n-compound, Zn-compound and P-compound in a divided manner is to stagger the addition time when the production of the polyester resin is carried out batchwise, or to change the place of addition when carrying out the continuous production. Can be performed. When the production of the polyester resin is performed in a continuous manner, a method of increasing the number of reaction vessels and separately adding the reaction vessels to at least two reaction vessels, separately adding at least two or more locations in the same reaction vessel in the progress of the reaction. And various methods such as a method of line-mixing a reaction vessel and a continuous section of the reaction vessel.

Mg compound, Ca compound, Co compound, M
As for the division ratio of the addition amount of the n compound and the Zn compound, the initial addition amount is preferably about 50% or less of the total addition amount, and particularly preferably 30% or less.

The dividing ratio of the addition amount of the P compound is preferably such that the initial addition amount is about 50% or less of the total addition amount.
It is particularly preferred that the content be 0% or less. In addition, Mg compound, Ca compound, Co compound, Mn compound and Zn
Preferably, it is added after the addition of the compound.

First Mg compound, Ca compound, Co compound
The addition time of the compound, the Mn compound, the Zn compound and the P compound may be before or during the esterification and transesterification reaction, or after the completion, but the addition time after the second time is during the esterification or transesterification reaction. Or after termination.

The Sb compound used in the present invention is added so that the content in the resulting polymer is in the range of 0.1 to 1.7 mol per 1 ton of the polymer as metal atoms. The Ti compound used in the present invention has a content in the produced polymer of 0 to 0.4 as metal atom in the polymer-1 ton.
Add so as to be in the molar range. The Ge compound used in the present invention is added so that the content in the resulting polymer is in the range of 0 to 0.7 mol per 1 ton of the polymer as metal atoms.

The limiting viscosity of the polyester resin of the present invention is:
0.57 to 0.90 dl / g, preferably 0.58 to
0.88 dl / g, more preferably 0.60 to 0.8
It is in the range of 5 dl / g. At 0.57 dl / g or less,
The mechanical properties of the obtained molded product are poor. Also, 0.90
When the dl / g exceeds dl / g, the resin temperature rises during melting by a molding machine or the like, and the thermal decomposition becomes severe, the amount of free low-molecular-weight compounds that affect fragrance retention increases, or the molded product is colored yellow. And other problems occur.

The amount of diethylene glycol constituting the polyester resin of the present invention is 1.5 to 1.5 of the glycol component.
It is 5.0 mol%, preferably 1.6 to 4.5 mol%, and more preferably 1.7 to 4.0 mol%. When the amount of diethylene glycol is 1.5 mol% or less, the density of the molded article specified in the present invention does not fall within the range specified in the present invention because the crystallization rate is high, and the transparency of the obtained molded article is poor. become worse. When the amount of diethylene glycol is 5.0 mol% or more, the glass transition point of the polyester resin decreases, the heat resistance of the obtained molded article decreases, and the acetaldehyde content during molding decreases due to poor heat stability. The amount of increase is large,
It has a bad effect on scent retention.

The acetaldehyde content of the polyester resin of the present invention is 10 ppm or less, preferably 8 ppm.
Or less, more preferably 5 ppm or less. When the content of acetaldehyde is 10 ppm or more, the contents such as containers molded from the polyester resin have poor flavor and odor.

Further, the cyclic 3 of the polyester resin of the present invention
The content of the monomer is 0.35% by weight or less, preferably 0.3% by weight.
It is at most 3% by weight, more preferably at most 0.32% by weight. When molding a heat-resistant hollow molded article or the like from the polyester resin of the present invention, heat treatment is performed in a heating mold. However, when the content of the cyclic trimer is 0.35% by weight or more, the heating mold is used. Oligomer attachment to the mold surface increases sharply,
The transparency of the obtained hollow molded article and the like is extremely deteriorated.

The polyester resin of the present invention can be produced by a commonly used melt molding method by using a hollow molded product, a film,
Can be molded. When a hollow molded article is produced, a transparent, heat-resistant hollow molded article can be produced from the polyester resin of the present invention using a known hot parison method or cold parison method.

In the case of manufacturing a hollow molded article using the polyester resin of the present invention, first, a preform is molded by injection molding, and then this is stretch-blown and molded into a bottle. Injection molding is generally performed at an injection temperature of about 265 to about 300 ° C. and an injection pressure of about 30 to about 70 kg / cm ² to form a preform. The plug portion of this preform is crystallized by heat treatment. In the case of the cold parison method, the preformed body obtained in this manner is used in an amount of about 80 to about 12
Preheat to 0 ° C, and about 80-
Cool to about 120 ° C. The preform is stretch blow molded in a blow mold at about 120 to about 210C and then heat treated for about 0.5 to about 30 seconds. The stretching ratio is usually 1.3 to 3.5 times in the machine direction and 2 to 6 in the circumferential direction.
It is better to double.

The polyester resin of the present invention can also be used for a laminated film or a laminated sheet with a different kind of film, a laminated body with a metal plate, or a multilayer hollow molded article.
The polyester resin of the present invention may contain various known additives such as a nucleating agent, a stabilizer, an antistatic agent, a coloring agent, an ultraviolet ray inhibitor, an antioxidant, a lubricant, and a release agent, if necessary. Is also good.

[0042]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. The method for measuring the main characteristic values will be described below.

1) Intrinsic viscosity (IV) It was determined from the solution viscosity at 30 ° C. in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent.

2) Diethylene glycol content (hereinafter referred to as [D
It was decomposed by methanol, and the amount of DEG was determined by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

3) Acetaldehyde content (hereinafter referred to as "AA content") A resin pellet sample / distilled water = 1 g / 2 ml was placed in a glass ampoule purged with nitrogen, and the upper portion was sealed and heated at 160.degree.
After extraction for a while, acetaldehyde in the extract after cooling was measured by high-sensitivity gas chromatography, and the concentration was determined as pp.
Indicated by m.

4) Cyclic trimer content of polyester resin A resin pellet sample was prepared by mixing hexafluoroisopropanol /
Dissolve in chloroform mixed solution, further add chloroform and dilute. After adding methanol to precipitate a polymer, the mixture is filtered. The filtrate was evaporated to dryness, made up to volume with dimethylformamide, and quantified by liquid chromatography.

5) Molding of Molded Product The dried polyester resin was molded using a M-100 injection molding machine manufactured by Meiki Seisakusho at a cylinder temperature of 290 ° C.
It is molded with a stepped flat mold cooled to 0 ° C. to obtain a stepped molded body. This stepped molded body is 2, 3, 4, 5, 6, 7, 8,
9, 10 and 11 mm thick molded plates of about 3 cm x about 5 cm square are provided in a step shape, and each piece weighs about 146 g
It is. A molded plate with a thickness of 2 mm is used for measuring the rate of density rise.
A molded plate having a thickness of 5 mm is cut out and used for measuring haze (haze degree%).

6) Haze (haze%) Using a molded plate having a thickness of 5 mm from the following molded step,
The measurement is performed using a Nippon Denshoku Hazemeter.

7) Heat treatment of molded plate and calculation of density rise rate A molded plate having a thickness of 2 mm was cut out from the stepped molded body.
After being immersed in a silicone oil bath (with a stirrer) controlled to a predetermined temperature for a predetermined time, the product is quickly taken out, put into n-hexane and rapidly cooled. After quenching, the silicon oil attached to the surface is washed with n-hexane, and the density is measured. The sample is heated at 140 ° C. and 180 ° C. at 10 second intervals. The heat treatment is repeatedly performed for five samples under one condition, and an average value of the density of the sample under each condition is obtained. The heat treatment time at each temperature and the density value of the formed plate are plotted to obtain a density rise curve. From this density rise curve, the density rise speed at each temperature is determined as follows. That is, 14
The density rise curve at 0 ° C. shows a density of 1.340 (g / c
m ³ ) heating time (t1 s) and density 1.3
The heating time (t2 seconds) corresponding to 60 (g / cm ³ ) is obtained and calculated by the following equation. Density increase rate (g / (cm ³ · second)) = 0.02 / (t
2-t1) Further, the density rise curve at 180 ° C. shows a density of 1.345.
(G / cm ³⁾ the heating time corresponding to (t1 seconds) and density 1.365 (g / cm ³⁾ corresponding to the heating time (t2
Second), and is calculated from the above equation.

8) Density of Polyester Resin Pellets and Heat-Processed Molded Plate 25 using a density gradient tube of carbon tetrachloride / n-heptane mixed solvent
Measure in ° C.

(Example 1) As an esterification apparatus, a first esterification reaction apparatus provided with a stirrer, a decomposer, a raw material charging port and a product outlet, and the inside of a reaction vessel were divided into two tanks. A stirrer was attached to the reaction tank, and a three-stage complete mixing tank type continuous esterification reaction apparatus comprising a second esterification reaction apparatus provided with a separator, a raw material inlet, and a product outlet was used. The molar ratio of EG to TPA 1.7 was added to the system where the reaction product was present in the first esterification reactor.
The EG slurry of TPA adjusted to the above was continuously supplied.
At the same time, an EG solution of magnesium acetate tetrahydrate is supplied from a supply port different from the TPA EG slurry supply port to 0.25 mol (about 6 ppm with respect to the produced polyester resin) as Mg atoms per ton of the produced polyester resin. At a normal pressure, an average residence time of 4 hours and a temperature of 25
The reaction was performed at 5 ° C. This reaction product is continuously taken out of the system and supplied to the first tank of the second esterification reactor,
It was taken out continuously from the second tank. The transfer from the first tank to the second tank employed an overflow method. An EG solution of phosphoric acid in an amount of 0.13 mol (about 4 ppm) as P atoms per ton of the produced polyester resin from the supply port on the inlet side of the first tank, the supply port on the inlet side of the second tank An EG solution of magnesium acetate tetrahydrate in an amount of 0.62 mol (about 15 ppm) as Mg atoms per 1 ton of the produced polyester resin and 1 ton of the produced polyester resin from the supply port at the intermediate position of the second tank An EG solution of phosphoric acid in an amount of 0.52 mol (approximately 16 ppm) as P atoms per unit was continuously added, and the reaction was carried out at a normal pressure and an average residence time of 2.5 hours for each tank at a temperature of 260 ° C. I let it.

Next, the esterification reaction product was continuously taken out from the second esterification reactor and sent to a two-stage continuous polycondensation reactor equipped with a stirrer, a separator, a raw material charging port and a product take-out port. Feeded continuously. From the polycondensation catalyst supply pipe connected to the transport pipe for the esterification reactant,
0.1 tons of Sb atoms per ton of the produced polyester resin.
An EG solution of antimony trioxide in an amount of 90 mol (about 110 ppm) and an EG of tetrabutyl titanate in an amount of 0.06 mol (about 3 ppm) as Ti atoms per ton of the produced polyester resin. The solution was supplied to the esterification reaction product, and polycondensation was performed at about 270 ° C. under reduced pressure in the continuous polycondensation reaction apparatus described above. PET obtained
The IV of the resin was 0.53. This resin was subsequently sent to a continuous solid-state polymerization apparatus and subjected to solid-state polymerization at about 205 ° C. under a nitrogen atmosphere. IV of the obtained PET resin is 0.74,
DEG content is 2.7 mol%, AA content is 3.4 ppm,
The cyclic trimer content is 0.30% by weight, and the density is 1.400 g.
/ Cm3. A molded plate for density measurement was formed by the above-mentioned method, subjected to a heat treatment, and the density was measured. 140 ° C
Density when heated for 60 seconds at 1.335 g / cm3, 1
The density increasing rate at 40 ° C. is 0.5 × 10 ⁻³ (g / (cm
³ )), the density when heated at 180 ° C. for 20 seconds is 1.335 g / cm ³ , and the density rise rate at 180 ° C. is 1.5 × 10 ⁻³ (g / (cm ³ .second)). )Met. The haze of the formed plate having a thickness of 5 mm was as good as 3.5%. The obtained PET resin was dried by a drier using a nitrogen stream, and a preform was molded at a resin temperature of 290 ° C. using an M-100 injection molding machine manufactured by Meiki Seisakusho. The preform plug portion was heated and crystallized by a home-made plug portion crystallizer, and then biaxially stretched and blow-molded using a Corplast LB-01 stretch blow molding machine.
The mixture was heat-set in a mold set at 5 ° C. for 5 seconds to obtain a 1500 ml hollow molded container (body portion average thickness 0.4 mm). The haze of the torso was as good as 1.1%.

Example 2 The same apparatus as in Example 1 was used, and the esterification reaction and melt polymerization were carried out under the same conditions as in Example 1 except that the amount and position of the metal compound added were changed. An EG solution of magnesium acetate tetrahydrate in such an amount as to give 0.41 mol (about 10 ppm) of Mg atoms per ton of the produced polyester resin from the supply port on the inlet side of the first tank of the second esterification reactor. An EG solution of phosphoric acid in an amount of 0.29 mol (approximately 9 ppm) as P atoms per ton of the produced polyester resin from a supply port at an intermediate position of the first tank; From the mouth as Mg atoms per ton of polyester resin produced: 1.
An EG solution of magnesium acetate tetrahydrate in an amount of 23 mol (about 30 ppm) and 1.0 mol (about 31 ppm) as P atoms per 1 ton of the produced polyester resin from the supply port at the intermediate position of the second tank. An EG solution of phosphoric acid was continuously added in such an amount as to obtain an esterification reaction. Then, in the same manner as in Example 1, 0.41 mol (approximately 50
ppm) of an EG solution of antimony trioxide and an EG solution of tetrabutyl titanate in an amount of 0.17 mol (about 8 ppm) as Ti atoms per ton of the produced polyester resin. The polycondensation reaction was carried out by supplying to the reaction product. IV of the obtained PET resin was 0.54. This resin was subsequently sent to a continuous solid-state polymerization apparatus and subjected to solid-state polymerization at about 205 ° C. under a nitrogen atmosphere. IV of the obtained PET resin is 0.75, DEG
Content is 2.9 mol%, AA content is 3.9 ppm, cyclic 3
The monomer content is 0.32% by weight and the density is 1.400 g / cm.
^{Was 3} . A molded plate for density measurement was formed by the above-mentioned method, subjected to a heat treatment, and the density was measured. 60 at 140 ° C
The density when heated for 1 second is 1.334 g / cm ³ , 140 ° C.
Density increase rate at 0.4 × 10 ^-3 (g / (cm ³
Seconds)), the density when heated at 180 ° C. for 20 seconds is 1.335 g / cm ³ , and the density rise rate at 180 ° C. is 1.1 × 10 ⁻³ (g / (cm ³ · second)). there were. The haze of the formed plate having a thickness of 5 mm was as good as 3.3%. In the same manner as in Example 1 from the obtained PET resin,
1500ml hollow molded container (mean wall thickness 0.4m)
m). The haze of the body was as good as 1.0%.

(Comparative Example 1) The total amount of phosphoric acid added in two portions in Example 1 and the same amount of antimony trioxide as in Example 1 were used in the first esterification apparatus. The total amount of magnesium acetate added in two portions was added to the first tank of the second esterification apparatus, and polycondensation was carried out under the same conditions as in Example 1 to obtain a prepolymer having an IV of 0.53. Obtained. This was subjected to solid-state polymerization using the same solid-phase polymerization equipment as in Example 1 under the same conditions, and had an IV of 0.74 and a DEG content of 2.7.
PET with mol%, AA content of 3.4 ppm, cyclic trimer content of 0.32% by weight and density of 1.399 g / cm3
A resin was obtained. The heat treatment of the molded plate was performed in the same manner as in Example 1, and the density was measured. The density was 1.341 g / cm ³ when heated at 140 ° C. for 60 seconds, and the density increase rate at 140 ° C. was 1.8 ×. 10 ^-3 (g / (cm ³ · second)), and the density when heated at 180 ° C. for 20 seconds is 1.342.
g / cm ³ , the rate of density increase at 180 ° C. is 4.8 × 10
^-3 (g / (cm ³ · second)). Further, the haze of the molded plate having a thickness of 5 mm was as high as 22.6%. In the same manner as in Example 1, a hollow container having an average thickness of 0.4 mm and 1500 ml was obtained. The body haze of this container is as high as 6.0%,
Transparency was poor.

[0055]

The polyester resin of the present invention is inexpensive,
It can be advantageously used as a molded product having excellent transparency and dimensional stability under heat.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // C08L 67:02 F term (reference) 4F071 AA44 AA82 AA88 AF30 AF45 AF54 AH05 BC04 BC11 4J002 CF061 EE016 GG01 4J029 AA04 AB04 AC01 AD10 AE01 AE03 BA03 CB06A HA01 HB01 JA091 JB131 JB171 JC751 JF251 JF361 JF471 KE05 KE12 KE15

Claims (4)

[Claims] 1. A polyester resin whose main repeating unit is ethylene terephthalate produced by using an antimony compound and a titanium compound and / or a germanium compound as a catalyst, and (a) amorphous molding formed from the polyester resin The body has a density of 1.338 (g / cm ³ ) or less when heated at 140 ° C. for 60 seconds, and
Density increase rate at 40 ° C. is 0.2 × 10 ^{−3 to} 0.6 ×
^10-3 (g / (cm ³ · second)), and (b) the density when the amorphous molded body is heated at 180 ° C. for 20 seconds is 1.338 (g / cm ³ ) or less. And 180
Density increase rate at 0.8 ° C. is 0.8 × 10 ^{−3 to} 3.0 × 10
^-3 (g / (cm ³ · second)). 2. An intrinsic viscosity of 0.70 to 0.90 dl /
g, the amount of copolymerized DEG is 1.5 to 1.5 of the glycol component.
2. The polyester resin according to claim 1, which has 5.0 mol% and a density of 1.37 g / cm ³ or more. 3. The polyester resin according to claim 1, which has an acetaldehyde content of 10 ppm or less and a cyclic trimer content of 0.35% by weight or less. 4. The polyester resin according to claim 1, wherein the polyester resin is for a hollow molded article.