JPH06322082A - Polyester and hollow container made using the same - Google Patents

Abstract

PURPOSE:To obtain a polyester which is reduced in mold fouling and has high production efficiency, and to provide a molding comprising the polyester. CONSTITUTION:This polyester is the one obtained from a dicarboxylic acid ingredient comprising terephthalic acid as the main component and a diol ingredient comprising ethylene glycol as the main component. This polyester contains monofunctional monomer units in an amount of 0.4-5mol% based on all dicarboxylic acid units, and has an intrinsic viscosity of 0.60-1.50dl/g and a cyclic trimer content of 0.40wt.% or lower. The hollow container comprises this polyester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polyesters useful in bottles, films, sheets and the like. More specifically, the present invention relates to a polyester having a small amount of oligomers in a resin and being less contaminated by oligomers in a mold or the like during molding, and having excellent productivity, heat resistance, mechanical strength and the like, and a molded product thereof.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter referred to as "P
ET) is excellent in mechanical strength, chemical stability, transparency and hygiene, and is relatively inexpensive and lightweight, so it is widely used as packaging material for various sheets, containers and fiber materials. , Especially carbonated drinks, fruit juice drinks, liquid seasonings,
Significant growth as a container for cooking oil, liquor and wine.

In the case of PET, for example, in the case of a bottle, a preform for a hollow molded body is molded by an injection molding machine, and this preform is stretch-blown in a mold having a predetermined shape. Further, in the case of a content liquid such as a fruit juice drink which needs to be hot-filled, it is general to further heat-fix in the blow mold or a separately provided mold to mold it into a bottle. However, in the conventional PET chips used for molding, the amount of the cyclic trimer containing an oligomer as a main component is usually 1 to 2% by weight in the melt-polymerized chip and usually 0.5 in the solid-phase polymerized chip.
~ 1.0 wt%, these oligomers,
During molding, it adheres to equipment such as molds and contaminates it. The contamination of the mold and the like causes the surface roughness and whitening of the molded product. Therefore, it is necessary to clean the mold etc. as often as possible.

Therefore, the conventional solid-phase polymerization time is extended,
Attempts have been made to reduce oligomers by increasing the amount of catalyst,
There is a limit to the reduction of oligomers by such a method,
And not an economical way. Also, JP-A-58-145
753 contains compounds selected from specific aliphatic monocarboxylic acids and their derivatives, and liquid paraffin.
A polyester resin composition characterized by containing ˜1000 ppm has been proposed. However, the main effect of the invention is that the wettability of the molded product and the mold is improved and the transfer of the oligomer to the mold during molding is suppressed, and the suppression of the by-product of the oligomer itself during molding is still suppressed. It was not enough. Further, in this publication, for example, the use of a compound having no ester bond forming ability such as liquid paraffin, or the addition of a monofunctional compound by dry blending, the added low molecular weight compound does not exist at the polyester terminal or almost at all. It may be present in the polyester resin without reaction. For this reason, there has been a problem that the intrinsic viscosity is lowered, the transparency is lowered, and in some cases, a part of the additive compound is eluted into the content of the molding container.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyester which has a small amount of oligomer by-products during molding and is unlikely to cause contamination of a mold or the like.

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a polyester obtained by blocking a part of the terminal functional groups of the polyester with a small amount of a monofunctional compound is effective. The inventors have found out that there has been reached the present invention. That is, the gist of the present invention is that the main component is terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component, and 1) contains 0.4 to 5 mol% of a monofunctional component unit based on all dicarboxylic acid component units, and 2). It has an intrinsic viscosity of 0.60 to 1.50 dl / g and 3) a polyester having a cyclic trimer content of 0.40% by weight or less and a molded product thereof.

The present invention will be described in detail below. For the terephthalic acid and ethylene glycol, which are the main components of the polyester of the present invention, known raw materials used in PET may be used. In the polyester of the present invention, the terephthalic acid unit is usually 50 mol% based on all dicarboxylic acid units.
Or more, preferably 80 mol% or more, more preferably 90 mol% or more.
It is in the range of mol% or more, and most preferably 95 mol% or more. Other carboxylic acid components may be used together as long as terephthalic acid is contained in the above proportion.

Dicarboxylic acid components other than terephthalic acid include phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, aromatic dicarboxylic acids typified by diphenylsulfonedicarboxylic acid, adipic acid, sebacine. Aliphatic carboxylic acids represented by acids, cyclohexane-1,4-
Examples thereof include alicyclic carboxylic acids represented by dicarboxylic acids and oxycarboxylic acids represented by oxybenzoic acid and glycolic acid. Of these dicarboxylic acids, phthalic acid, isophthalic acid and naphthalenedicarboxylic acid are preferably used. More preferably, isophthalic acid and naphthalenedicarboxylic acid are used, and most preferably isophthalic acid is used. These dicarboxylic acids may be used alone or in combination of two or more.

The ethylene glycol used in the prepolymer used in the present invention is usually 50 mol% in all diol components.
Or more, preferably 80 mol% or more, more preferably 90 mol% or more.
It is used in the range of mol% or more, most preferably 95 mol% or more. Other diol components may be used together as long as ethylene glycol is contained in the above proportion.

Diol components other than ethylene glycol include aliphatic compounds such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol and diethylene glycol. Examples thereof include glycols, alicyclic glycols such as cyclohexanedimethanol, and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S. Of these, preferably 1,4-butanediol,
Hexamethylene glycol, diethylene glycol, cyclohexanedimetal, bisphenol A, bisphenol S, and more preferably 1,4-butanediol, diethylene glycol, cyclohexanedimethanol, and bisphenol A are used. These diol components may be used alone or in combination of two or more.

The polyester of the present invention is characterized by containing a monofunctional component unit in addition to the above dicarboxylic acid and diol components. Examples of the compound added to form the monofunctional component unit include monofunctional compounds having a hydroxyl group or a carboxyl group represented by the following general formulas (I), (II) and (III), and esters thereof. Forming derivatives are indicated.

[0012]

[Chemical 1]

(X represents a hydroxyl group or a carboxyl group, R ¹ represents a divalent hydrocarbon group having 0 to 20 carbon atoms, and R ^{2 to} R ⁶ represent hydrogen or an alkyl group or alkoxy group having 1 to 12 carbon atoms. Group, phenyl group, aralkyl group and naphthyl group or represents Cl, Br, or F)

[0014]

[Chemical 2]

(X represents a hydroxyl group or a carboxyl group, R ¹ represents a divalent hydrocarbon group having 0 to 20 carbon atoms, and R ^{2 to} R ⁸ represent hydrogen or an alkyl group or alkoxy group having 1 to 12 carbon atoms. Group, phenyl group, aralkyl group and naphthyl group or represents Cl, Br, or F)

[0016]

Embedded image CH ₃ —R ¹ —X (III)

(X represents a hydroxyl group or a carboxyl group, and R ¹ represents a divalent hydrocarbon group having 6 to 20 carbon atoms) As the monofunctional compound represented by the general formula (I), benzoic acid, p-toluic acid and its structural isomers, 2,3-
Dimethylbenzoic acid and its structural isomers, 2,4,6-
Aromatic carboxylic acids such as trimethylbenzoic acid, 4-propylbenzoic acid, 4-isopropylbenzoic acid, p-t-butylbenzoic acid and p-chlorobenzoic acid, phenol, p-
Cresol and its structural isomers, 3-5-dimethylphenol and its structural isomers, p-propylphenol and its structural isomers, pt-butylphenol and its structural isomers, 2,4,6-trimethylphenol and its Structural isomers, benzyl alcohol, p-methylbenzyl alcohol and structural isomers thereof, 2,4
-Dimethylbenzyl alcohol and its structural isomers,
4-ethylbenzyl alcohol, pt-butylbenzyl alcohol, 2-phenylethyl alcohol, 2-methylphenethyl alcohol and its structural isomers, 3-
Mention may be made of hydroxy compounds such as phenylpropyl alcohol and structural isomers thereof.

Of these, p-propylphenol and its structural isomers, pt-butylphenol and its structural isomers are preferable, and pt-butylphenol is particularly preferable. Examples of the monofunctional compound represented by the general formula (II) include 1-naphthol and its structural isomers, nuclear-substituted naphthols such as 2-methyl-1-naphthol and its structural isomers, 1-naphthalene methanol and its compounds. Structural isomers, α-methyl-2-naphthalenemethanol and its structural isomers, 1-naphthalene ethanol and its structural isomers, 1-naphthoic acid and its structural isomers, 1-naphthylacetic acid and its structural isomers You can

Of these, 1-naphthol and structural isomers thereof and 2-methyl-1-naphthol are preferable, and 1-naphthol and structural isomers thereof are particularly preferable. Examples of the monofunctional compound represented by the general formula (III) include aliphatic carboxylic acids such as lauric acid, stearic acid, palmitic acid, oleic acid and behenic acid, and aliphatic hydroxy compounds such as lauryl alcohol and stearyl alcohol. Can be mentioned.

Of these, preferably stearic acid,
Among them are palmitic acid and stearyl alcohol, with stearic acid, palmitic acid and stearyl alcohol being particularly preferred. These monofunctional compounds can be added at any stage during raw material charging, esterification reaction, and polymerization reaction, but it is preferable to add them at the time of raw material charging from the viewpoint of easy handling. It is presumed that the end of the polymer chain is blocked by the addition of the monofunctional compound, whereby the prepolymer after melt polymerization is solid-phase polymerized, and the by-product of oligomer during molding is suppressed. .

The amount of the above-mentioned monofunctional component unit is 0.4 to 5 mol%, preferably 0.5 to 2 mol% based on the total dicarboxylic acid component units. If the amount is less than the above range, the effect of reducing the oligomer during molding is small and the superiority to the conventional PET is not recognized. On the other hand, when the amount exceeds the above range, the polymerization rate decreases, which is not preferable. The polyester of the present invention described above is produced according to a conventionally known method for PET. The manufacturing method will be described in detail below.

As a melt polymerization method, a dicarboxylic acid typified by terephthalic acid and a diol component typified by ethylene glycol and a monofunctional compound are directly esterified under pressure and then further heated. There is a method of gradually reducing the pressure to cause a polycondensation reaction. Alternatively, it can be produced by transesterification using an ester derivative of terephthalic acid, for example, dimethyl terephthalic acid and ethylene glycol, and then adding a monofunctional compound to the resulting reaction product and further polycondensing.

Such polycondensation reaction may be carried out in one step or in a plurality of steps. When carried out in a plurality of stages, the polymerization reaction conditions are such that the reaction temperature of the first stage polycondensation is usually 250 to 300 ° C., preferably 260 to 290 ° C., and the pressure is usually 10 to 0.1 torr, preferably 5 to 5.
It is 0.5 torr. When the polycondensation reaction is carried out in two stages, the polycondensation reaction conditions of the first stage and the second stage are within the above ranges respectively, and when carried out in three or more stages, the second stage to the final stage. The reaction conditions of the polycondensation reaction up to the first step are between the reaction conditions of the first step and the reaction conditions of the final step.

For example, when the polycondensation reaction is carried out in three stages, the reaction temperature for the second stage polycondensation reaction is usually 2
60 to 295 ° C, preferably 270 to 285 ° C,
The pressure is usually in the range of 50-2 Torr, preferably 40-5 Torr. The intrinsic viscosity reached in each of these polycondensation reaction steps is not particularly limited, but it is desirable that the proportion of the intrinsic viscosity in each stage be smoothly distributed, and the intrinsic viscosity can be obtained from the polycondensation reactor at the final stage. The intrinsic viscosity of polyester is usually 0.45 to 0.80 dl / g,
It is preferably 0.50 to 0.70 dl / g. Also,
It is desirable that the polyester chips obtained by polycondensation have an average particle diameter of usually 2.0 to 5.5 mm, preferably 2.2 to 4.0 mm.

In the above esterification reaction, transesterification reaction and polycondensation reaction, it is preferable to use an esterification catalyst, a transesterification catalyst, a polycondensation catalyst, a stabilizer and the like. Known compounds as the transesterification catalyst, for example,
One or more of calcium, titanium, manganese, zinc, sodium and lithium compounds can be used, but manganese compounds are particularly preferable from the viewpoint of transparency.

As the polymerization catalyst, one or more known compounds such as germanium, antimony, titanium and cobalt compounds can be used, but preferably germanium or antimony compound is used. The addition amount of both the esterification catalyst and the polymerization catalyst is usually 5 to 2000 ppm by weight, preferably 10 parts by weight, based on the total amount of the polymer components.
It is used in the range of ˜500 ppm by weight, more preferably 20 to 200 ppm by weight. When it is less than the range, a sufficient reaction rate cannot be obtained, and when it exceeds the range, heat resistance is deteriorated, which is not preferable.

If the germanium compound is further specified, examples of the compound include a germanium oxide, an inorganic acid salt, a halide sulfide, etc., and the amount thereof is the prepolymer to be produced or the polyester after solid state polymerization. Germanium atom is usually 10-100 weight pp
m, preferably 20 to 80 ppm by weight, more preferably 30 to 60 ppm, in terms of by-product and thermal stability of the oligomer.

There is no problem in using an alkali metal compound together with a germanium compound. The content of alkali metal atoms is 0.
It is preferable that the molar amount is 5 to 2.5 times.
The molar ratio is more preferably 0.7 to 2.0 times, and most preferably 0.8 to 1.8 times. If the amount is less than the range, the effect of improving the polymerization rate is not sufficiently observed, and if the amount exceeds the range, coloring or the like occurs, which is not preferable.

Examples of the stabilizer include phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, triphenyl phosphite, trisdodecyl phosphite, Phosphites such as trisnonylphenyl phosphite, acidic phosphates such as methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate and phosphoric acid, phosphorous acid, polyphosphoric acid Phosphorus compounds such as acids are preferred. The stabilizer is usually 10 to 1000 weight pp in the total weight of the raw material, as the weight of phosphorus atom in the stabilizer.
m, preferably in the range of 20 to 200 ppm. Further, particularly when a germanium compound is used as a polymerization catalyst, the phosphorus atom contained in the prepolymer or the polyester after solid-phase polymerization is usually 0.3 to 1.5 times by weight ratio with respect to the germanium atom, Preferably 0.
It is preferable to use it in the range of 4 to 1.0 times.

Further, a dicarboxylic acid component other than terephthalic acid and a diol component other than diethylene glycol and diethylene glycol may be contained in a small amount as long as the above-mentioned constitutional requirements of the present invention are not deviated. These dicarboxylic acid components include isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid,
Diphenyl sulfone dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid and structural isomers thereof, malonic acid,
Examples of aliphatic carboxylic acids such as succinic acid and adipic acid, oxyacids or derivatives thereof include p-hydroxybenzoic acid, p-hydroxybenzoic acid ester and glycolic acid.

The diol components include 1,2-propanediol, 1,3-propanediol and 1,4-propanediol.
Aliphatic glycols such as butanediol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, alicyclic glycols such as cyclohexanedimethanol, and aromatic dihydroxy compound derivatives such as bisphenol A and bisphenol S. be able to. An amount that is substantially equivalent to the total diol component and the total dicarboxylic acid component is used.

Next, in order to obtain the polyester of the present invention, it is necessary to further subject the granular polyester chips obtained by melt polymerization as described above to solid phase polymerization treatment. The polyester chips supplied to the solid phase polymerization may be heated to a temperature lower than the temperature at which the solid phase polymerization is performed in advance to perform pre-crystallization, and then supplied to the solid phase polycondensation step. In such a pre-crystallization step, the polyester chips in a dry state are usually 100 ° C to 200 ° C, preferably 110 ° C to 1 ° C.
It can also be carried out by heating at a temperature of 80 ° C., usually for 1 minute to 4 hours.

The solid-state polymerization process in which the above-mentioned granular polyester chips are supplied comprises at least one stage. The solid phase polymerization temperature is usually 190 to 230 ° C, preferably 195 to
It is carried out under an inert atmosphere of nitrogen, argon, carbon dioxide or the like under the conditions of 225 ° C. and a pressure of usually 1 kg / cm ³ G to 10 Torr, preferably normal pressure to 100 Torr. The higher the temperature is, the shorter the polymerization time is to reach the desired physical properties, but it is usually 1 to 50 hours, preferably 5 to 30 hours.
The time is more preferably 10 to 25 hours.

The polyester of the present invention can be obtained by appropriately selecting the conditions of the above solid-phase polymerization treatment. The polyester of the present invention thus obtained has P
Films, sheets, containers and other packaging materials can be molded using melt molding methods commonly used in ET. Further, the mechanical strength can be improved by stretching the polyester of the present invention in at least a uniaxial direction.

In producing a stretched film, the stretching temperature may be set between the glass transition temperature of the polyester of the present invention and a temperature 70 ° C. higher than that, and usually 40 to 40 ° C.
170 degreeC, Preferably it is 60-140 degreeC. The stretching may be uniaxial or biaxial, but biaxial stretching is preferable from the viewpoint of practical physical properties of the film. In the case of uniaxial stretching, the stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times, and in the case of biaxial stretching, it is usually 1 in both the longitudinal and transverse directions. 1 to 8 times, preferably 1.5 to 5 times. The longitudinal magnification / lateral magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-fixed to improve heat resistance and mechanical strength. The heat setting is usually 120 ° C to melting point, preferably 150 ° C to 2 under tension such as compressed air.
It is carried out at 30 ° C. for usually several seconds to several hours, preferably several tens of seconds to several minutes.

In producing the hollow molded article, a preform molded from the polyester of the present invention is stretch blow molded, and an apparatus conventionally used in PET blow molding can be used. In particular,
For example, a preform is once molded by injection molding or extrusion molding, and the biaxially stretched blow molding method such as the hot parison method or the cold parison method is applied as it is or after processing the plug portion and the bottom portion and reheating them. . In this case, the molding temperature, specifically the temperature of each part of the cylinder of the molding machine and the temperature of the nozzle, is usually 270 to 290 ° C.

The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 1.5 in the machine direction.
˜3.5 times, and 2 to 5 times in the lateral direction. The obtained hollow molded article can be used as it is, but in the case of a content liquid that requires heat filling such as fruit juice drink and oolong tea, it is generally further heat-fixed in a blow mold to impart further heat resistance. Then used. Heat setting is usually 100 to 200 ° C., preferably 120 to 1 under tension such as compressed air.
It is carried out at 80 ° C. for several seconds to several hours, preferably several seconds to several minutes.

[0038]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Various measuring methods used in this example are shown below.

(1) Amount of cyclic trimer (hereinafter referred to as "CT amount") 200 mg of polyester sample was mixed with 2 ml of chloroform / hexafluoroisopropanol (volume ratio 3/2).
It was then dissolved in and diluted with 20 ml of chloroform. To this, 10 ml of methanol was added to reprecipitate a sample, which was filtered to obtain a filtrate. After the filtrate was dried and solidified, a liquid obtained by dissolving the residue in 25 ml of dimethylformamide was analyzed and quantified by liquid chromatography.

(2) p-t-Butylbenzoic acid, stearic acid, pt-butylphenol, stearyl alcohol (1) Reaction amount (1) After addition of methanol, the reprecipitated product was decomposed with methanol by a conventional method and gas chromatographed. It was analyzed and quantified by the Tograph method.

(3) Intrinsic viscosity: Measured at 30 ° C. in a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1). (4) Germanium atom content 2.0 g of a polyester sample was incinerated by a conventional method in the presence of sulfuric acid, completely decomposed, and then made up to a volume of 100 ml with distilled water.

(5) Phosphorus atom content (hereinafter referred to as "P amount") It was quantified by an emission analysis method in the same manner as the analysis of the germanium atom content. (6) Inert gas flow rate The amount of gas flowing per unit time (hr) and per unit resin weight (kg) is shown as 1 atm and volume (L) converted to 25 ° C.

Example 1 15.6 kg of terephthalic acid, 5.8 ethylene glycol
A slurry of 2 kg and 169.5 g of p-t-butylbenzoic acid was prepared, 0.30 kg of bis (β-hydroxyethyl) terephthalate was added in advance, and the mixture was sequentially supplied to an esterification tank kept at 250 ° C. over 4 hours. did.

After the end of the supply, the latter half amount of the esterification reaction that had been allowed to proceed for 1 hour was transferred to a polycondensation tank, and 1.14 g of phosphoric acid (150 ppm by weight with respect to the polymer), germanium dioxide 0.
Charged with 91 g (120 ppm by weight of polymer) 25
The temperature was gradually raised from 0 ° C. to 280 ° C., the pressure was gradually reduced from normal pressure, and the pressure was maintained at 0.5 mmHg. After reacting for 3 hours, extrude into strands and cut, then CT
A prepolymer chip having an amount of 0.98% by weight, an intrinsic viscosity of 0.56 dl / g, a Ge amount of 43 wtppm, and a P amount of 23 wtppm was obtained. 51% of p-t-butylbenzoic acid was reacting with the glycol end, and p for all dicarboxylic acids
The amount of -t-butylbenzoic acid was 1.0 mol%.

Next, the surface of the prepolymer chip was crystallized at 150 ° C. with a stirring crystallization machine (manufactured by Bepex Co.), and then transferred to a stationary solid-state polymerization tower under a nitrogen flow of 20 L / kg · hr. After drying at about 150 ° C. for 3 hours, solid phase polymerization was performed at 215 ° C. for 20 hours to obtain a solid phase polymerization chip. The CT amount in the solid-state polymerized chip was 0.31% by weight, and the Ge amount was 43% by weight.
The amount of pm and P was 23 weight ppm. Intrinsic viscosity is 0.7
It was 8 dl / g.

Next, using the solid-state polymerized chip, each cylinder and nozzle temperature 280 ° C., screw rotation speed 100 rpm, injection time 10 seconds, mold cooling water temperature 10 ° C. injection molding machine manufactured by Toshiba Corp. A preform was molded with IS-60B. After the mouthpiece of this preform was heated and crystallized by a self-made crystallization machine, it was blow-molded by a stretch blow molding machine set to a residual heat furnace temperature of 90 ° C., a blow pressure of 20 kg / cm ³ , and a molding cycle of 10 seconds, Part average meat pressure 30
A bottle having a size of 0 μm and an internal volume of 1 L was obtained, and subsequently, compression tension was set in a mold set at 150 ° C. and heat setting was performed for 10 seconds. The CT amount in the ground sample of the mouth plug of the bottle was 0.32 ppm by weight. In addition, 2000 bottles were continuously molded, but no metal contamination was observed in any of injection molding, stretch blow molding, and heat setting.

Example 2 Example 1 was repeated except that 102.8 g of benzyl alcohol was used in place of p-t-butylbenzoic acid.
The prepolymer after reacting for 3 hours and 10 minutes had an intrinsic viscosity of 0.56 dl / g, a CT amount of 1.00% by weight, and a Ge amount of 49.
The weight ppm and the amount of P were 25 weight ppm. 52% of benzyl alcohol has reacted with the carboxyl end,
The ratio of benzyl alcohol to all dicarboxylic acids was 1.0 mol%. Also, CT of solid-state polymerization chip
The amount was 0.29% by weight, and the intrinsic viscosity was 0.80 dl / g. Furthermore, C in the plug part of the preform after injection molding
The T content was 0.30% by weight.

Example 3 Example 4 was repeated except that 244.0 g of stearyl alcohol was used in place of p-t-butylbenzoic acid. The intrinsic viscosity of the prepolymer obtained after the reaction for 3 hours and 15 minutes was 0.57 dl / g, the CT amount was 1.01 wt%, the Ge amount was 44 wt ppm, and the P amount was 31 wt ppm. 55% of stearyl alcohol had reacted with the carboxyl terminal, and the ratio of stearyl alcohol to all dicarboxylic acids was 1.1 mol%. The solid-state polymerized chip has a CT amount of 0.30% by weight and an intrinsic viscosity of 0.
It was 76 dl / g. Further, the CT amount in the plug portion of the preform after injection molding was 0.31% by weight.

Example 4 Example 4 was repeated except that 2.0 g of cesium acetate was added when the raw materials were charged. The prepolymer obtained after reacting for 2 hours and 30 minutes had an intrinsic viscosity of 0.57 dl / g and CT.
The amount was 1.00 wt%, the Ge amount was 42 wt ppm, and the P amount was 29 wt ppm. 52% of p-t-butylbenzoic acid had reacted with the glycol terminal, and the amount of p-t-butylbenzoic acid was 1.0 mol% based on all dicarboxylic acids. Further, the CT amount of the solid-state polymerization chip is 0.31% by weight,
The intrinsic viscosity was 0.79 dl / g. Furthermore, the CT amount in the plug portion of the preform after injection molding is 0.31% by weight.
Met.

Example 5 The procedure of Example 1 was repeated, except that the amount of terephthalic acid added as a dicarboxylic acid at the time of charging was 15.30 kg and 0.312 kg of isophthalic acid was added. Reaction time 3 hours and 20 minutes, CT amount 0.91% by weight, intrinsic viscosity 0.57d
A prepolymer having 1 / g and a Ge content of 43 ppm by weight was obtained.
51% of p-t-butylbenzoic acid reacted with the glycol terminal, and the amount of p-t-butylbenzoic acid was 1.1 mol% based on all dicarboxylic acids. The amount of CT of the chips obtained after solid-phase polymerization was 0.30% by weight, the intrinsic viscosity was 0.89 dl / g, the Ge amount was 45 ppm by weight, and the P amount was 2
It was 8 ppm by weight. Further, the CT amount in the plug portion of the preform after injection molding was 0.31% by weight.

Comparative Example 1 Example 1 except that p-t-butylbenzoic acid was not added.
I went the same way. The reaction required 2 hours and 50 minutes, and the prepolymer thus obtained had an intrinsic viscosity of 0.57 dl / g, a CT amount of 1.00 wt%, a Ge amount of 42 wt ppm and a P amount of 24 wt ppm. Also, the CT amount of the solid-state polymerization chip is 0.
The intrinsic viscosity was 30% by weight and the intrinsic viscosity was 0.78 dl / g. Further, the CT amount in the plug portion of the preform after injection molding was 0.45% by weight, which was an extremely large increase in CT amount.

[0052]

The polyester resin of the present invention has high transparency and contains a small amount of oligomers. In addition, the polyester of the present invention is suitable as a packaging material because the amount of active terminals, which is one of the causes of oligomer formation, is small, and particularly the amount of oligomer attached to the mold is small during melt molding using the mold. Therefore, continuous molding is possible and productivity is good, which is preferable.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Kishiro Sanboshi Kasei Co., Ltd. Research Institute, 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (3)

[Claims] 1. A terephthalic acid as a dicarboxylic acid component,
Ethylene glycol as a main component as a diol component, 1) 0.4 to 5 mol% of a monofunctional component unit with respect to all dicarboxylic acid component units, 2) an intrinsic viscosity of 0.60 to 1.50 dl / g, 3) A polyester characterized in that the content of the cyclic trimer is 0.40% by weight or less. 2. A terephthalic acid as a dicarboxylic acid component,
Ethylene glycol as a main component as a diol component, 1) 0.4 to 5 mol% of a monofunctional component unit based on all dicarboxylic acid component units, and 4) an intrinsic viscosity of 0.45 to 0.80 dl / g. The polyester according to claim 1, which is obtained by solid-state polymerization of a certain prepolymer. 3. A polyester hollow container obtained by blow molding a preform obtained by injection molding or extrusion molding of the polyester of claim 1.