JP2006045555A - Polyester and polyester molded product comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester which has excellent transparency, in which the formation of acetaldehyde at molding is retarded, and from which a large, thick and hollow molded product having excellent pressure resistance and pressure resistance at high temperature is efficiently produced; and to provide a polyester molded product comprising the polyester. <P>SOLUTION: The polyester contains a compound containing at least one kind of an element selected from the group consisting of Al, Ge and Ti as a polycondensation catalyst, and is composed of ethylene terephthalate as a main repeating unit. The polyester has 0.62-0.88 dl/g intrinsic viscosity X. The molded product molded at 280°C and having 5 mm thickness has ≤30% haze (A), and the difference Y between the haze (A) of the molded product molded at 280°C and having 5 mm thickness, and the haze (B) of the molded product molded at 280°C and having 4 mm thickness, and the intrinsic viscosity X satisfy the expression: Y=A-B≤70-60X. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyester suitably used as a material for a molded article such as a hollow bottle, a sheet-like product, and a stretched film, including a beverage bottle, and a polyester molded article comprising the polyester, particularly excellent in transparency and variation in transparency. A large-sized hollow molded body with reduced acetaldehyde formation during molding, excellent pressure resistance or heat-resistant dimensional stability, and sheet-like material with excellent transparency, slipperiness and dimensional stability after molding And a stretched film. In addition, the present invention relates to a polyester that has good releasability from a heat treatment mold when molding a hollow molded body and has excellent long-term continuous moldability.

  Polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) are excellent in mechanical and chemical properties, and thus have high industrial value and are widely used as fibers, films, sheets, bottles, and the like. ing.

  As a material for containers such as seasonings, oils, beverages, cosmetics, and detergents, various resins are employed depending on the type of filling contents and the purpose of use.

  Among these, polyester is excellent in mechanical strength, heat resistance, transparency, and gas barrier properties, and is particularly suitable as a material for molded articles such as containers for filling beverages such as juices, soft drinks, and carbonated drinks.

For example, such a polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape and stretch blow molded to be used for a soft drink. It can be made into a hollow molded container, or it can be formed into a heat-resistant or heat-resistant pressure-resistant hollow molded container by heat-treating the preform plug portion (crystallization of the plug portion) and then stretching blow molding and heat-treating the body portion (human set). It is common.

  In general, for such applications, PET produced mainly from terephthalic acid and ethylene glycol and using various metal compounds as a polycondensation catalyst is mainly used.

  Among the polycondensation catalysts, the antimony catalyst is an inexpensive catalyst having excellent catalytic activity. However, when it is used in a main component, that is, in an added amount such that a practical polymerization rate is exhibited. Because antimony is deposited during polycondensation, darkening and foreign matter occur in the polyester, and the resulting PET has a faster crystallization rate and superior transparency compared to the case where a germanium compound or a titanium compound is used as a catalyst. It is very difficult to obtain a hollow molded body, particularly a large hollow molded body.

  Under such circumstances, a polyester that does not contain antimony at all or does not contain antimony as a main catalyst component is desired.

  As a method for solving the above problems, for applications requiring transparency such as PET bottles, as a method for solving the problems of the antimony catalyst, for example, it is transparent by defining the usage ratio of the antimony compound and the phosphorus compound. The method (for example, refer patent document 1) by which the property is improved is disclosed. However, it cannot be said that a hollow molded product made of polyester obtained by this method has sufficient transparency.

  Moreover, the continuous manufacturing method (for example, refer patent document 2) of the polyester excellent in transparency using an antimony trioxide, phosphoric acid, and a sulfonic acid compound is disclosed. However, the polyester obtained by such a method has a problem that the thermal stability is poor and the hue of the obtained hollow molded article is deteriorated.

  Also disclosed is a method for improving the transparency of a molded article by reducing the crystallinity by copolymerizing a copolymer component such as isophthalic acid in an amount of 1.5 to 7.5 mol% (see, for example, Patent Document 3). However, there is a problem that the heat resistance of the obtained molded article is deteriorated, and a solution is desired.

  PET also contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. Furthermore, PET produces acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the obtained molded body material is increased, so that beverages filled in the hollow molded body, etc. Affects the flavor and smell.

  Examples of catalysts that give polyesters that have excellent catalytic activity other than antimony compounds and that do not have the above problems include germanium compounds, titanium compounds, and aluminum compounds. When these metal compounds are used as catalysts, they are obtained. Although the transparency of the molded body from PET is improved as compared with the case of using an antimony catalyst, the acetaldehyde content of the molded body is still not a satisfactory level but a problem.

  In recent years, polyester containers such as polyethylene terephthalate have come to be used as containers for low flavor beverages such as mineral water and oolong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but it is becoming increasingly important to reduce the acetaldehyde content of the beverage container. In addition, for metal cans for beverages, for the purpose of process simplification, hygiene, pollution prevention, etc., there is a method of making cans using a metal plate whose inner surface is coated with a polyester film whose main repeating unit is ethylene terephthalate. It has come to be adopted. In this case as well, it is sterilized by heating at a high temperature after filling the contents. At this time, it is found that the use of a film having a sufficiently low acetaldehyde content is an essential requirement for improving the flavor and odor of the contents. I came.

For these reasons, various measures have conventionally been taken to reduce the acetaldehyde content in the polyester. As these measures, for example, a method of reducing the AA content by solid-phase polymerization of melt-polycondensed polyester (see, for example, Patent Document 4), a polyester prepolymer obtained by melt polymerization is under reduced pressure or inactive A method for reducing oligomers and aldehydes by subjecting to solid phase polymerization under the flow of gas (see, for example, Patent Documents 5 and 6), 0.05 weight of polyamide resin containing metaxylylene group with respect to 100 weight parts of polyester resin A method using a polyester composition to which more than 1 part by weight and less than 1 part by weight are added (for example, see Patent Document 7), or a polyester composition containing a thermoplastic polyester and a specific polyamide whose terminal amino group concentration is regulated within a certain range. Polyester containers made of materials (for example, see Patent Document 8), polyester containers A method of conditioning the polymer so that the moisture content is 2000 ppm or more, followed by crystallization and solid-phase polymerization (see, for example, Patent Document 9), treating the polyester particles with hot water at 50 to 200 ° C., and then under reduced pressure Alternatively, a method of performing heat treatment under an inert gas flow (for example, see Patent Document 10), a method of extracting and washing with water or an organic solvent before and after solid-phase polymerization (for example, see Patent Document 11), and thermoforming A method for reducing the molding temperature as much as possible and a method for reducing the shear stress during thermoforming as much as possible have been proposed. However, even in a molded body using polyester obtained by these methods, it cannot be said that oligomers and acetaldehyde can be reduced to a problem-free level, and the problem remains unsolved. Further, a blend of solid-phase polymerized PET and copolymerized polyethylene terephthalate (for example, see Patent Document 12) has been proposed, and by using this, the AA content of the hollow molded body can be reduced. Since the copolymer component is present, there is a problem in the heat resistance and pressure resistance of the obtained molded body, which is not satisfactory and a solution is awaited.
In recent years, thinning of bottles has been attempted, and as a result, attempts have been made to increase the molecular weight in order to increase the strength of the bottle, but by increasing the molecular weight, the melt viscosity during molding increases and the amount of acetaldehyde generated increases. There was an increasing problem.

JP-A-6-279579 Japanese Patent Laid-Open No. 10-36495 Japanese Patent Laid-Open No. 57-16024 JP-A-53-73288 JP 55-89330 A JP 55-89331 A Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425 JP-A-2-298512 JP-A-8-120062 Japanese Patent Laid-Open No. 55-13715 JP 58-45254 A

  The present invention solves the problems of the conventional methods described above, is excellent in transparency, has little fluctuation in transparency, suppresses the formation of acetaldehyde during molding, and is hollow with excellent pressure resistance or heat-resistant dimensional stability. An object of the present invention is to provide a polyester capable of efficiently producing a molded article, particularly a large-sized hollow molded article having excellent pressure resistance and heat and pressure resistance by high speed molding, and a polyester molded article comprising the polyester.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, the polyester of the present invention is a polyester containing ethylene terephthalate as a main repeating unit, containing a compound containing at least one element selected from the group consisting of Al, Ge, and Ti as a polycondensation catalyst, and having an intrinsic viscosity X 0.62 to 0.88 deciliter / gram, haze (A) of 5 mm-thick molded body molded at 280 ° C. is 30% or less and haze (A) of 5 mm-thick molded body molded at 280 ° C. The polyester is characterized in that the difference Y in haze (B) of the 4 mm-thick molded product molded at 280 ° C. and the intrinsic viscosity X of the polyester satisfy the following formula:
Y = A−B ≦ 70−60X
(In the formula, A is the haze (%) of a molded product having a thickness of 5 mm molded at 280 ° C., B is the haze (%) of the molded product having a thickness of 4 mm molded at 280 ° C., and X is the intrinsic viscosity of the polyester (deciliter / gram). ).)

  The polyester of the present invention has an intrinsic viscosity X of preferably 0.63 to 0.86 deciliter / gram, more preferably 0.65 to 0.84 deciliter / gram, and a molded article having a thickness of 5 mm formed at 280 ° C. The haze (A) is preferably 20% or less, more preferably 15% or less, and the haze (A) of a 5 mm-thick molded product molded at 280 ° C. and the haze of a 4 mm-thick molded product molded at 280 ° C. The difference Y in (B) and the intrinsic viscosity X of the polyester are preferably polyesters satisfying the formula of Y ≦ 65-60X, more preferably Y ≦ 60-60X.

  When the intrinsic viscosity X of the polyester is less than 0.62 deciliter / gram, the transparency of the obtained molded article is deteriorated, which is a problem. On the other hand, if it exceeds 0.88 deciliter / gram, heat generation during molding becomes intense and the effect of reducing acetaldehyde becomes low. When the haze (A) of a 5 mm-thick molded product molded at 280 ° C. exceeds 30%, the transparency of the molded product becomes very poor, which is a problem. Moreover, the lower limit of the haze is about 1%, and even if the lower limit is reduced below this, the economic effect on the above problems is very small. When the haze difference Y is Y> 70-60X, cooling is insufficient when cooling the molded body when molding a thick molded body of about 4 mm or more, resulting in crystallization, and only a molded body with poor transparency is obtained. It is a problem because it is not possible.

  That is, the polyester of the present invention gives a molded article having a good transparency even when a preform such as a large bottle preform having a wide melt molding temperature range of about 4 mm or more is molded at a low temperature. In addition, it is an optimal polyester for large bottles having good transparency that are stretch blow molded from the preform, and it is essential to satisfy the above formula.

  The degree of crystallinity and generation of the polyester are determined by the selection of the catalyst system at the time of polyester production, the selection of production conditions, the selection of production equipment, or the handling of the polyester chips (hereinafter, these may be referred to as how to produce the polyester). The ease of melting of crystals and crystal nuclei varies. When melt-molding polyester with a molding machine that has a crystallinity that is considerably high and that contains crystal nuclei that do not melt easily (such as highly oriented crystallized crystals and inorganic substances that have a crystal promoting effect) Since the crystal nuclei in the polyester are not easily melted, if the molding is performed at a lower temperature, many crystal nuclei remain in the molded product. In the case of such a thick molded body, the transparency is extremely deteriorated. Furthermore, in such a molded body, crystallization further proceeds during preheating before stretching, and becomes white and the stretchability deteriorates. In an extreme case, uniform stretching becomes impossible.

  In particular, in the case of a thick molded body having a thickness of about 4 mm or more, it is difficult to quickly transfer heat to the center of the molded body. Therefore, the above problem may occur due to slight temperature fluctuations of the mold and uneven temperature during preheating. Therefore, stable production is difficult, and strict condition management is required for stable production.

On the other hand, depending on how the polyester is produced, a polyester containing only crystal nuclei that melts easily at almost the same degree of crystallinity, or a polyester containing only crystal nuclei that melts at a lower temperature can be obtained. Even if a polyester is molded under the same conditions as described above, since there are few crystal nuclei, crystallization hardly occurs when the molded body is cooled, and transparency is maintained even in the case of a thick molded body of about 4 mm or more. The

  In the present invention, the molding temperature (the temperature set from the nozzle of the injection molding machine M-150C-DM manufactured by Meiki Seisakusho in the molding method of the stepped molding plate described in the measurement section below) is 280 ° C. The difference (Y) between the haze (A) of the 5 mm-thick molded body and the haze (B) of the 4 mm-thick molded body was adopted as a scale.

  By using the polyester of the present invention having the above characteristics, it is excellent in transparency, and there is no occurrence of transparent spots (for example, a whitened flow pattern or a partially whitened or wrinkled product generated in a molded product) In addition, a hollow molded article having a low acetaldehyde content or formaldehyde content and excellent flavor retention can be obtained. In particular, it is optimal as a polyester for thick preforms having a thickness of about 4 mm or more such as large bottles.

  In this case, the polyester is preferably a polyester containing ethylene terephthalate units, preferably 96 mol% or more, more preferably 96.5 mol% or more. When the ethylene terephthalate unit is less than 96 mol%, the molecular orientation at the time of stretch molding becomes insufficient, and the mechanical strength and heat resistance of the stretch molded product become insufficient, which is a problem. Thus, even if it is polyester containing 96 mol% or more of ethylene terephthalate units, it becomes possible to obtain a molded article having a low acetaldehyde content with excellent transparency by molding at a lower temperature.

  In this case, it is preferable that the acetaldehyde content of the molded body obtained by molding the polyester at 290 ° C. is 20 ppm or less. The acetaldehyde content is preferably 18 ppm or less, more preferably 15 ppm or less, and particularly preferably 10 ppm or less. When the acetaldehyde content exceeds 20 ppm, the flavor retention of the obtained molded article is deteriorated, which causes a problem. Here, the acetaldehyde content of the molded product is a value obtained for a sample from a 2 mm thick plate of a stepped molded plate molded at 290 ° C. according to the molding method described in the following “Measurement Method” section. .

  In this case, the content of the cyclic trimer is preferably 0.70% by weight or less. The content of the cyclic trimer of the polyester of the present invention is preferably 0.60% by weight or less, more preferably 0.50% by weight or less, and particularly preferably 0.35% by weight or less. The lower limit of the cyclic trimer content is 0.20% by weight or more, preferably 0.22% by weight or more, and more preferably 0.25% by weight or more from the viewpoint of economical production. When molding a heat-resistant hollow molded article or the like from the polyester of the present invention, heat treatment is carried out in a heating mold, but when the cyclic trimer content is 0.70% by weight or more, the heating mold is used. The adhesion of the oligomer to the mold surface increases rapidly, and the transparency of the obtained hollow molded article is very deteriorated.

In this case, it is desirable that the cyclic trimer increase amount when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less. The increase amount of the cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is preferably 0.3% by weight or less, more preferably 0.1% by weight or less. If the amount of cyclic trimer increased after melting at 290 ° C for 60 minutes exceeds 0.40% by weight, the amount of cyclic trimer will increase when the resin is melted and the oligomer will adhere to the surface of the heated mold. Increases rapidly, and the transparency of the obtained hollow molded article or the like is extremely deteriorated.
Here, the amount of increase in cyclic trimer when melted for 60 minutes at a temperature of 290 ° C. is obtained from a 3 mm thick plate of a stepped molded plate obtained by the molding method described in the “Measurement Method” section below. This is the value obtained for the sample.

In this case, the above polyester can be molded.
In this case, the molded body can be a hollow molded body, a sheet-like material, or a stretched film obtained by stretching the sheet-like material in at least one direction.

  The polyester has excellent transparency, low acetaldehyde content, excellent flavor retention, low cyclic trimer content, and low mold contamination during continuous molding, such as a hollow molded product, Sheet-like materials, stretched films and the like can be provided.

  The present invention provides a polyester that can maintain transparency even when molded at a lower temperature, generates a small amount of aldehydes, and gives a molded product having excellent mechanical properties such as pressure resistance when formed into a molded product. . In addition, since the polyester of the present invention has improved moldability at a lower temperature, there is less distortion during molding, and a molded body having excellent heat-resistant dimensional stability, particularly a large-sized hollow molded product with high thickness can be efficiently produced by high-speed molding. Provided is a polyester that can be produced and that has excellent pressure resistance and heat-resistant dimensional stability, is excellent in long-term continuous moldability and does not stain the mold, and a molded body comprising the same. . The polyester of the present invention can meet high required quality in the field of containers, sheets and the like.

Hereinafter, embodiments of the polyester of the present invention will be specifically described.
That is, the polyester of the present invention is a linear polyester containing 90 mol% or more of ethylene terephthalate units, preferably 96 mol% or more, more preferably 96.5 mol% or more, particularly preferably 97.0 mol% or more. It is a linear polyester.

  Examples of the dicarboxylic acid used for copolymerization of the polyester include isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyru 4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, Aromatic dicarboxylic acids such as 1,3-phenylene dioxydiacetic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, Examples thereof include aliphatic dicarboxylic acids such as glutaric acid and dimer acid and functional derivatives thereof, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid and functional derivatives thereof.

  Examples of the glycol used for copolymerization of the polyester include aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, bisphenol A, and alkylene oxides of bisphenol A. Examples include aromatic glycols such as adducts.

  Furthermore, examples of the other copolymer component composed of the polyfunctional compound in the polyester include trimellitic acid and pyromellitic acid as acidic components, and glycerin and pentaerythritol as glycol components. The amount of the above copolymerization component used must be such that the polyester remains substantially linear. Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

The polyester of the present invention having the above characteristics includes, for example, polyester A and polyester B having the following characteristics having ethylene terephthalate as a main repeating unit as a main component, and the composition ratio of both is 95/5 to 5 by weight. Although it can obtain as polyester which is / 95, it is not limited to this. Here, the difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is in the range of 0.05 to 0.25 deciliter / gram, and the difference in chip bulk density between polyester A and polyester B is 0.00. It is preferable that the difference (ΔTc2) between 10 gram / cubic centimeter and the crystallization temperature when the temperature of polyester A is lowered and the crystallization temperature when polyester B is lowered is within 15 ° C.

Polyester A: Intrinsic viscosity IV _A is 0.60 to 0.75 deciliter / gram, sodium content is 1.1 ppm or less, calcium content, magnesium content, silicon content is at least one content is 5 ppm or less, Polyester having a bulk density of the chip of 0.80 to 0.97 grams / cubic centimeter, a crystallization temperature of 150 to 180 ° C. at the time of temperature rise measured by DSC, and 160 to 190 ° C. at the time of the temperature fall.

Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.90 deciliter / gram, sodium content is 1.1 ppm or less, calcium content, magnesium content, at least one content of silicon content is 5 ppm or less, Polyester having a bulk density of the chip of 0.80 to 0.97 grams / cubic centimeter, a crystallization temperature of 150 to 180 ° C. at the time of temperature rise measured by DSC, and 160 to 190 ° C. at the time of the temperature fall.

  Here, the DSC measurement is performed by the following method on a molded plate (2 mm thickness) injection-molded at 290 ° C. by the following method.

The difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is preferably 0.06 to 0.23 deciliter / gram, more preferably 0.07 to 0.20 deciliter / gram, particularly preferably 0. 10 to 0.17 deciliter / gram. When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the acetaldehyde content of the obtained molded product cannot be reduced, and the flavor retention cannot be improved. Further, when the above-mentioned intrinsic viscosity difference exceeds 0.25 deciliter / gram, a thickness unevenness, a whitened flow pattern, or the like is generated on the obtained molded product, which causes a problem.

  The difference in bulk density between them is preferably within 0.08 grams / cubic centimeter, more preferably within 0.05 grams / cubic centimeter, and particularly preferably within 0.03 grams / cubic centimeter. When the difference in bulk density exceeds 0.10 g / cubic centimeter, when the molded product is produced from the polyester, the variation of the blending ratio in the time series direction becomes large, so that the intrinsic viscosity and crystallization of the molded product are increased. Variations in properties occur, resulting in a molded product having large thickness spots, stretch spots, and transparent spots, which is a problem. The effect is not clear when the difference in bulk density between the two is within 0.01 gram / cubic centimeter. Further, the difference (ΔTc2) between the crystallization temperature when the temperature of polyester A is lowered and the crystallization temperature when polyester B is lowered (ΔTc2) is preferably within 13 ° C., more preferably within 10 ° C., and particularly preferably within 8 ° C. When the difference in crystallization temperature at the time of temperature drop (ΔTc2) exceeds 15 ° C., the polyester component having a higher crystallization temperature at the time of temperature drop greatly affects the crystallization at the time of cooling the molded body, and thus obtained molding is obtained. The transparency of the body becomes very bad.

  In the polyester of the present invention containing the above-mentioned polyester A and polyester B as main components, the low IV component acts as a plasticizer, so that the fluidity of the melt in the extruder is improved and the thermal conductivity is improved. Further, since the crystal nucleus melts even at a lower temperature, it becomes a melt with a slow crystallization rate. Further, the difference (ΔTc2) between the crystallization temperature when the polyester A is lowered and the crystallization temperature when the polyester B is lowered is 15 ° C. Therefore, crystallization is less likely to occur when the molded body is cooled from the melt.

The intrinsic viscosity IV _A of polyester A is preferably 0.62 to 0.74 deciliter / gram, more preferably 0.63 to 0.73 deciliter / gram, and the sodium content is preferably 1.0 ppm or less, more preferably each 0.5 ppm or less, more preferably 0.3 ppm or less, particularly preferably 0.1 ppm or less, calcium content, magnesium content, silicon content is preferably 1 ppm or less, more preferably 0.5 ppm or less, respectively. Preferably each is 0.3 ppm or less, the bulk density is preferably 0.82 to 0.96 gram / cubic centimeter, particularly preferably 0.83 to 0.95 gram / cubic centimeter, and the crystallization temperature during temperature rise is preferably 153 to 178 ° C, more preferably 155 to 175 ° C, Crystallization temperature when the temperature is preferably one hundred and sixty-two to one hundred eighty-five ° C., more preferably 165 to 180 ° C.. If the intrinsic viscosity IV _A of the polyester A is less than 0.60 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.75 deciliter / gram, the effect of reducing acetaldehyde is lowered.

  Further, when the sodium content exceeds 1.1 ppm, or when the calcium content, the magnesium content, and the silicon content exceed 5 ppm, the crystallization speed is increased, and the thick hollow molding preform is formed. The plug portion is excessively crystallized, and therefore the amount of shrinkage of the plug portion does not fall within the specified value range, resulting in poor capping of the plug portion, causing leakage of the contents, and the preform for hollow molding. Whitening occurs, which makes normal stretching impossible. The calcium content, the magnesium content, and the silicon content are all preferably 5 ppm or less.

  When the bulk density is less than 0.80 grams / cubic centimeter, the flowability of the chips in the molding machine is poor and the mixing of the two becomes insufficient. Also, it is useless from an economic point of view to produce chips exceeding 0.97 grams / cubic centimeter. Further, when the crystallization temperature of polyester A at a temperature rise is less than 150 ° C., the transparency of the molded article is deteriorated, and when it exceeds 180 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. When the crystallization temperature of the polyester A when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.86 deciliter / gram, more preferably 0.75 to 0.83 deciliter / gram, and the sodium content is preferably 1.0 ppm or less, more preferably each. 0.5 ppm or less, more preferably each 0.3 ppm or less, particularly preferably 0.1 ppm or less, calcium content, magnesium content, silicon content, each preferably 1 ppm or less, more preferably 0.5 ppm or less, More preferably 0.3 ppm or less, the bulk density is preferably 0.82 to 0.96 gram / cubic centimeter, particularly preferably 0.83 to 0.95 gram / cubic centimeter, and the crystallization temperature at the time of temperature rise is preferably 153 178 ° C, more preferably 155 to 175 ° C, Crystallization temperature when the temperature is preferably one hundred and sixty-two to one hundred eighty-five ° C., more preferably 165 to 180 ° C.. The intrinsic viscosity of the polyester B IV _B If there is less than 0.73 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.90 deciliter / gram, heat generation during molding becomes intense and the effect of reducing acetaldehyde becomes low.

  Further, when the sodium content exceeds 1.1 ppm, or when the calcium content, the magnesium content, and the silicon content exceed 5 ppm, the crystallization speed is increased, and the thick hollow molding preform is formed. The plug portion is excessively crystallized, and therefore the amount of shrinkage of the plug portion does not fall within the specified value range, resulting in poor capping of the plug portion, causing leakage of the contents, and the preform for hollow molding. Whitening occurs, which makes normal stretching impossible. The calcium content, the magnesium content, and the silicon content are all preferably 5 ppm or less.

  The bulk density is the same as that of polyester A. Moreover, when the crystallization temperature at the time of temperature rising of polyester B is less than 150 degreeC, the transparency of a molded object will worsen, and when it exceeds 180 degreeC, the effect of improving the crystallization rate of a plug part will worsen. When the crystallization temperature of the polyester B when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

  Moreover, it is preferable that the composition of the polyester A and the polyester B is substantially the same. Here, “substantially the same” means that the acid component and the glycol component in each polyester are preferably 95 mol% or more, more preferably 97 mol% or more, particularly 98 mol% or more. Is preferred.

  The polyester according to the present invention can basically be produced by a conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. These may be comprised from a batch-type reaction apparatus, and may be comprised from the continuous-type reaction apparatus. The melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately. Hereinafter, an example of a preferable continuous production method of the polyester according to the present invention will be described by taking polyethylene terephthalate (PET) as an example, but the present invention is not limited thereto. That is, a direct esterification method in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other copolymerization components to distill off water and esterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, or , Produced by a transesterification method in which dimethyl terephthalate, ethylene glycol, and other copolymerization components as required are reacted to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst. Is done. Then, when the intrinsic viscosity is increased or the low acetaldehyde content or the low cyclic trimer content is used, such as a heat-resistant container for low flavor beverages or a film for inner surfaces of metal cans for beverages. The resulting melt polycondensed polyester is subsequently subjected to solid state polymerization.

  First, when a low polymer is produced by an esterification reaction, 1.02 to 2.0 mol, preferably 1.03 to 1.4 mol of ethylene glycol is added to 1 mol of terephthalic acid or an ester derivative thereof. The contained slurry is prepared and continuously supplied to the esterification reaction step.

In the esterification reaction, water or alcohol produced by the reaction is removed out of the system by a rectification column under conditions where ethylene glycol is refluxed using a multistage apparatus in which at least two esterification reactors are connected in series. While implementing. The temperature of the first stage esterification reaction is 240 to 270 ° C., preferably 245 to 265 ° C., and the pressure is 0.2 to 3 kg / cm ² G, preferably 0.5 to ² kg / cm ² G. The temperature of the esterification reaction in the final stage is usually 250 to 280 ° C, preferably 255 to 275 ° C, and the pressure is usually 0 to 1.5 kg / cm ² G, preferably 0 to 1.3 kg / cm ² G. . When carried out in three or more stages, the reaction conditions for the esterification reaction in the intermediate stage are conditions between the reaction conditions for the first stage and the reaction conditions for the final stage. The increase in the reaction rate of these esterification reactions is preferably distributed smoothly at each stage. Ultimately, it is desirable that the esterification reaction rate reaches 90% or more, preferably 93% or more. By these esterification reactions, low-order condensates having a molecular weight of about 500 to 5,000 are obtained.

  When terephthalic acid is used as a raw material, the esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but may be carried out in the presence of a polycondensation catalyst.

  Also, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and lithium carbonate When a small amount of a basic compound such as sodium carbonate, potassium carbonate or sodium acetate is added, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate is relatively low (3% relative to all diol components). Mol% or less).

  Next, in the case of producing a low polymer by transesterification, 1.1 to 2.0 mol, preferably 1.2 to 1.5 mol of ethylene glycol was contained with respect to 1 mol of dimethyl terephthalate. The solution is prepared and continuously fed to the transesterification step.

  The transesterification reaction is carried out while removing methanol generated by the reaction outside the system using a rectification column under the condition that ethylene glycol is distilled back using an apparatus in which 1 to 2 transesterification reactors are connected in series. To do. The temperature of the first stage transesterification is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the transesterification reaction in the final stage is usually 230 to 270 ° C., preferably 240 to 265 ° C., and as the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Co, Ca, Ba, carbonates Further, Pb, Zn, Ge oxide or the like is used. A low-order condensate having a molecular weight of about 200 to 500 is obtained by these transesterification reactions.

  Dimethyl terephthalate, terephthalic acid or ethylene glycol, which is the starting material, includes virgin dimethyl terephthalate derived from para-xylene, ethylene glycol derived from terephthalic acid or ethylene, as well as methanol decomposition from used PET bottles. A recovered raw material such as dimethyl terephthalate, terephthalic acid, bishydroxyethyl terephthalate or ethylene glycol recovered by a chemical recycling method such as decomposition of ethylene glycol or ethylene glycol can also be used as at least part of the starting material. Needless to say, the quality of the recovered raw material must be refined to a purity and quality suitable for the intended use.

  Subsequently, the obtained low-order condensate is supplied to a multistage melt condensation polymerization process. The polycondensation reaction conditions are as follows: the first stage polycondensation reaction temperature is 250 to 290 ° C., preferably 260 to 280 ° C., and the pressure is 500 to 20 Torr, preferably 200 to 30 Torr. The temperature is 265 to 300 ° C., preferably 275 to 295 ° C., and the pressure is 10 to 0.1 Torr, preferably 5 to 0.5 Torr. When carried out in three or more stages, the reaction conditions for the intermediate stage polycondensation reaction are conditions between the reaction conditions for the first stage and the reaction conditions for the last stage. The degree of increase in intrinsic viscosity achieved in each of these polycondensation reaction steps is preferably distributed smoothly. A single-stage polycondensation apparatus may be used for the polycondensation reaction.

  The polycondensation reaction is performed using a polycondensation catalyst. As the polycondensation catalyst, it is preferable to use at least one compound selected from Ge, Ti or Al compounds. These compounds are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries and the like.

  Examples of the Ge compound include amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution obtained by heating and dissolving crystalline germanium dioxide in water, or a solution obtained by adding ethylene glycol to this and heat treatment. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water, or a solution in which ethylene glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is preferably 10 to 150 ppm, more preferably 13 to 100 ppm, and still more preferably 15 to 70 ppm as the residual amount of Ge in the polyester.

  Examples of Ti compounds include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate, and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl oxalate compounds such as titanium strontium oxalate, titanium trimellitate, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Titanium with potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid Complex compound, a complex oxide of titanium and silicon or zirconium, a reaction product of titanium alkoxide and the phosphorus compound. The Ti compound is added so that the remaining amount of Ti in the produced polymer is in the range of 0.1 to 50 ppm.

  Al compounds include aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, aluminum phosphonate and other inorganic acid salts, aluminum n-propoxide, aluminum iso-propoxide Aluminum alkoxides such as aluminum n-butoxide and aluminum t-butoxide, aluminum chelate compounds such as aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum, etc. Organic aluminum compounds and partial hydrolysates thereof, aluminum oxide, etc. It is. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the remaining amount of Al in the produced polymer is in the range of 5 to 200 ppm.

  In the production of the polyester according to the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination as necessary. The alkali metal or alkaline earth metal is preferably at least one selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba, and the use of an alkali metal or a compound thereof is preferable. More preferred. When using an alkali metal or a compound thereof, use of Li, Na, K is particularly preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.

  The alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution, or the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.

  Furthermore, the polyester according to the present invention contains at least one element selected from the group consisting of silicon, manganese, iron, cobalt, zinc, gallium, strontium, zirconium, niobium, molybdenum, indium, tin, hafnium, and thallium. You may contain the metal compound to contain. These metal compounds include saturated aliphatic carboxylates such as acetates of these elements, unsaturated aliphatic carboxylates such as acrylates, aromatic carboxylates such as benzoic acid, and halogens such as trichloroacetic acid. Hydroxycarboxylates such as carboxylates and lactates, inorganic acid salts such as carbonates, organic sulfonates such as 1-propanesulfonate, organic sulfates such as lauryl sulfate, oxides, hydroxides, chlorides Products, alkoxides, acetylacetonates and the like, and are added to the reaction system as powders, aqueous solutions, ethylene glycol solutions, ethylene glycol slurries and the like. These metal compounds are added so that the residual amount of elements of these metal compounds per ton of the produced polymer is in the range of 0.05 to 3.0 mol. These metal compounds can be added at any stage of the polyester formation reaction step.

  Also, as stabilizers, phosphoric acid, phosphoric acid esters such as polyphosphoric acid and trimethyl phosphate, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphine compounds It is preferable to use at least one phosphorus compound selected from the group consisting of: Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, 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 stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the produced polymer is preferably in the range of 5 to 100 ppm.

  When an Al compound is used as the polycondensation catalyst, it is preferably used in combination with a phosphorus compound, and is preferably used as a solution or slurry in which an aluminum compound and a phosphorus compound are previously mixed in a solvent. In the case of an Al compound, a more preferable phosphorus compound is at least one selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. It is a phosphorus compound. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as thermal stability of the polyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

The melt polycondensation polyester obtained as described above is obtained by, for example, extruding the melt polyester from the die pores into water satisfying at least one of the following (1) to (4) after completion of the melt polycondensation. A method of cutting, or a method of forming chips while cooling with cooling water satisfying at least one of the following (1) to (4) after extruding into the air through the die pores after completion of the melt polycondensation Is made into a chip.
Na ≦ 1.0 (ppm) (1)
Mg ≦ 1.0 (ppm) (2)
Si ≦ 2.0 (ppm) (3)
Ca ≦ 1.0 (ppm) (4)
In addition, it is preferable to use water that satisfies all of (1) to (4).

  The sodium content (Na) in the cooling water is preferably Na ≦ 0.5 ppm, more preferably Na ≦ 0.1 ppm. The magnesium content (Mg) in the cooling water is preferably Mg ≦ 0.5 ppm, more preferably Mg ≦ 0.1 ppm. Further, the content (Si) of silicon in the cooling water is preferably Si ≦ 0.5 ppm, more preferably Si ≦ 0.3 ppm. Furthermore, the calcium content (Ca) in the cooling water is preferably Ca ≦ 0.5 ppm, and more preferably Ca ≦ 0.1 ppm.

  Next, the previous melt polycondensed polyester chip is preferably pre-crystallized in a continuous crystallization apparatus having two or more stages in an inert gas atmosphere. For example, in the case of PET, the temperature of 100 to 180 ° C. is 1 minute to 5 hours in the first stage precrystallization, and then the temperature of 160 to 210 ° C. is 1 minute to 3 hours in the second stage precrystallization. In the pre-crystallization of the second and higher stages, it is preferable to perform crystallization step by step at a temperature of 180 to 210 ° C. for 1 minute to 3 hours. The crystallinity of the chip after crystallization is preferably in the range of 30 to 65%, preferably 35 to 63%, and more preferably 40 to 60%. The crystallinity can be obtained from the density of the chip.

  Next, solid phase polymerization is carried out in an inert gas atmosphere or under reduced pressure at an optimum temperature for the prepolymer so that the increase in intrinsic viscosity due to solid phase polymerization is 0.10 deciliter / gram or more. For example, in the case of PET, the upper limit of the solid phase polymerization temperature is preferably 215 ° C. or lower, more preferably 210 ° C. or lower, particularly 208 ° C. or lower, and the lower limit is 190 ° C. or higher, preferably 195 ° C. or higher. is there.

  It is preferable to set the chip temperature to about 70 ° C. or less, preferably 60 ° C. or less, more preferably 50 ° C. or less within about 30 minutes, preferably within 20 minutes, more preferably within 10 minutes after completion of the solid phase polymerization.

  Polyester A and polyester B can be produced by appropriately controlling the type and amount of polycondensation catalyst, melt polycondensation, solid phase polymerization conditions, and the like. It can also be obtained by a method of giving an impact to the polyester chip thus obtained, and a method of blending a polyolefin resin, particularly polyethylene, polyamide resin, polyoxymethylene resin, etc. as described below.

The chip shape of polyester A and polyester B may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like. The average particle diameter is usually 1.0 to 4 mm, preferably 1.0 to 3.5 mm, and more preferably 1.0 to 3.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. The weight of the chip is practically in the range of 5 to 40 mg / piece. In addition, when it is necessary to improve the solid-phase polymerization rate or to reduce the content of aldehydes more effectively, the average weight of the chips is preferably 1 to 5 mg / piece.

  The polyester of the present invention in which the increase amount of the cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less is a deactivation treatment of at least one polycondensation catalyst of polyester A and polyester B Can be manufactured.

  Examples of the method of deactivating the polyester polycondensation catalyst include a method of contacting the polyester chip with water, water vapor or water vapor-containing gas.

  Examples of the hydrothermal treatment method include a method of immersing polyester A, polyester B, or polyester containing these as main components in water, a method of spraying water on these chips with a shower, and the like. The treatment time is 5 minutes to 2 days, preferably 10 minutes to 1 day, more preferably 30 minutes to 10 hours, and the water temperature is 20 to 180 ° C., preferably 40 to 150 ° C., more preferably 50 to 120 ° C.

  When the polyester chip is contacted with water vapor or water vapor containing gas, the water vapor or water vapor containing gas or water containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably used per 1 kg of the granular polyester. The water vapor is supplied as water vapor in an amount of 0.5 g or more, or is present to bring the granular polyester into contact with water vapor. The contact between the polyester chip and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours. The processing method may be either a continuous method or a batch method.

  Further, as another means for deactivating the polycondensation catalyst, there is a method in which a phosphorus compound is blended with the polyester and mixed and reacted in a molten state such as during molding to deactivate the polycondensation catalyst.

  As a method of blending a phosphorous compound with polyester, a predetermined amount of phosphorous compound is polyester by a method of dry blending the phosphorous compound with the polyester or a method of mixing a polyester masterbatch chip in which a phosphorous compound is melt-kneaded and blended with a polyester chip. And a method of inactivating the polycondensation catalyst by melting in an extruder or a molding machine, a method of immersing chips in a phosphorus compound solution, particularly a phosphoric acid aqueous solution, and a method of adding as a master batch. These phosphorus compounds may be copolymerized with polyester.

  Examples of the phosphorus compound used include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples thereof are the compounds described above, and these may be used alone or in combination of two or more.

  When a polyester A chip and a polyester B chip are formed by dry blending, if the resin stays in the molding machine or if the molding conditions fluctuate (lengthening the molding cycle), the remaining catalyst is melting. Since the transesterification proceeds, the molecular weight becomes uniform, and the plasticizing effect due to the low IV component cannot be obtained, and the effects of the present application may not be exhibited. However, the use of at least one of polyester A or polyester B, preferably in which the polyester catalyst is deactivated, reduces the transesterification during the molding, and the quality of the molded product due to variations in molding conditions. It is also preferable from the viewpoint that the variation of the above can be suppressed.

  The polyester of the present invention can be obtained by uniformly mixing the polyester A and the polyester B at a predetermined ratio by a conventionally known method. For example, the above polyester A and the above polyester B are dry blended with a tumbler, V-type blender, Henschel mixer, static mixer, etc., and the dry blended mixture is 1 with a single screw extruder, twin screw extruder, kneader, etc. For example, a method of melting and mixing more than once. Specifically, it is common that the polyester A and the polyester B are uniformly mixed at a predetermined ratio in the form of chips by the appropriate method, dried, and then subjected to molding.

  When the polyester is to be obtained by dry blending the polyester A chip and the polyester B chip by the above-described method, if the mixing ratio of both is large, the change in the intrinsic viscosity of the molded article made of polyester As a result, fluctuations in crystallization characteristics and the like occur, and the characteristics such as acetaldehyde content, transparency, and thickness of the obtained molded article fluctuate, which is a big problem. In addition, when the polyester after dry blending is supplied to a dryer or molding machine, or discharged from these devices, or when the polyester is moved in a transfer pipe by a gas, the polyester is moved. The blending ratio of A or polyester B may vary.

  Fluctuation rate of the blend ratio of polyester A and polyester B chips before supply to molding machine and before melt molding is within ± 5%, preferably within ± 3%, more preferably within ± 1% It is.

  Variation factors of the blending ratio include a difference in true density and a bulk density between the two chips, and the true density is mainly determined by crystallization conditions, solid phase polymerization conditions such as solid phase polymerization temperature and time, and bulk. The density is determined by the chip size, the chip shape (cut state), the amount of fine powder (also called fine), fine particles, and the like.

  The density of the polyester A chip and the polyester B chip according to the present invention is 1.370 grams / cubic centimeter or more, preferably 1.380 grams / cubic centimeter or more, more preferably 1.390 grams / cubic centimeter or more, particularly preferably 1. Desirably 395 grams / cubic centimeter or more. Further, if it is attempted to obtain a chip having a density of 1.415 g / cubic centimeter or more, there is a problem in that chip fusion occurs during solid phase polymerization. When the density of the chip is less than 1.390 grams / cubic centimeter, the content of the cyclic trimer cannot be reduced to 0.7% by weight or less, and problems such as mold contamination occur. In the case of a certain heat resistant molded body, it is not preferable.

The difference in density between the polyester A chip and the polyester B chip according to the present invention is within 0.025 gram / cubic centimeter, preferably within 0.02 gram / cubic centimeter, and more preferably within 0.01 gram / cubic centimeter. When the difference in density exceeds 0.025 grams / cubic centimeter, when the molded product is produced from the polyester, the variation of the compounding ratio in the time series direction becomes large, so that the intrinsic viscosity and crystallization characteristics of the molded product are increased. This causes a problem that a molded product having large thickness spots, stretch spots, and transparent spots is generated.
Moreover, the chip size and the bulk density of the chips of polyester A and polyester B according to the present invention are as described above.

  Moreover, although the said polyester contains the fine resulting from the said polyester A or B which generate | occur | produces during manufacture, it is preferable that the content is 0.1-5000 ppm. The fine content is preferably 0.1 to 3000 ppm, more preferably 0.1 to 1000 ppm, further preferably 0.1 to 500 ppm, and most preferably 0.1 to 100 ppm. When the content of fine is less than 0.1 ppm, the crystallization rate becomes very slow, and the crystallization of the plug portion of the hollow molded container becomes insufficient, so that the amount of shrinkage of the plug portion is within the specified range. It will not fit within and will not be capped. When the content exceeds 5000 ppm, the variation in blending amount and blending amount of the polyester A and the polyester B is likely to occur, and as a result, the intrinsic viscosity variation of the molded body becomes large, and the crystallization speed and stretchability vary. Arise. In the case of a sheet-like material, the transparency and the surface state are deteriorated, and the fluctuation of these characteristics is large. When this is stretched, the thickness unevenness is deteriorated. In addition, the degree of crystallinity of the plug part of the hollow molded body becomes excessive and fluctuates, and therefore the shrinkage amount of the plug part does not fall within the specified value range, resulting in poor capping of the plug part and leakage of contents. In addition, the preform for the hollow molded body is whitened, so that normal stretching is impossible. In particular, the fine content of the polyester for the hollow molded body is preferably 0.1 to 500 ppm.

  Similarly, the fine content of the polyester is preferably 0.1 to 5000 ppm. The fine content is preferably 0.1 to 3000 ppm, more preferably 0.1 to 1000 ppm, further preferably 0.1 to 500 ppm, and most preferably 0.1 to 100 ppm.

  The formaldehyde content of a molded article obtained by molding the polyester of the present invention at 290 ° C. is 7 ppm or less, preferably 5 ppm or less, more preferably 3 ppm or less, and further preferably 2 ppm or less. When the formaldehyde content is 7 ppm or more, the flavor and odor of the contents such as a container molded from this polyester are deteriorated.

  The amount of diethylene glycol copolymerized in the polyester of the present invention is 1.3 to 5.0 mol%, preferably 1.5 to 4.0 mol%, more preferably 1. It is 8 to 3.5 mol%, more preferably 2.0 to 3.0 mol%, particularly preferably 2.0 to 2.9 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in acetaldehyde content and formaldehyde content becomes large, which is not preferable. Moreover, when diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded object worsens.

Furthermore, the polyester of the present invention preferably contains 0.1 ppb to 50000 ppm of at least one resin selected from the group consisting of polyolefin resins, polyamide resins, and polyacetal resins. The blending ratio of the resin used in the present invention to the polyester is 0.1 ppb to 10000 ppm, preferably 0.3 ppb to 1000 ppm, more preferably 0.5 ppb to 100 ppm, still more preferably 1.0 ppb to 1 ppm, particularly preferably. 1.0 ppb to 45 ppb. When the blending amount is less than 0.1 ppb, the crystallization speed becomes very slow and the crystallization of the plug part of the hollow molded body becomes insufficient. Therefore, if the cycle time is shortened, the shrinkage amount of the plug part is specified. Since it does not fall within the range of values, capping defects occur, and the stretched heat-fixed mold that forms a heat-resistant hollow molded body is heavily soiled, and when trying to obtain a transparent hollow molded body, the mold is frequently cleaned. There must be. On the other hand, if it exceeds 50000 ppm, the crystallization speed becomes high, and the crystallization of the plug portion of the hollow molded body becomes excessive, and the shrinkage amount of the plug portion does not fall within the specified value range, resulting in capping failure and the content. Leakage, and the preform for the hollow molded body is whitened, which makes normal stretching impossible. Further, in the case of a sheet-like material, if it exceeds 50000 ppm, the transparency becomes very poor, the stretchability is also impaired, and normal stretching is impossible, and only a stretched film with large thickness spots and poor transparency can be obtained. .
Furthermore, by making it within the range, variation in crystallinity is suppressed, and stable molding becomes possible.

  Examples of the polyolefin resin blended in the polyester of the present invention include a polyethylene resin, a polypropylene resin, and an α-olefin resin. These resins may be crystalline or amorphous.

  Examples of the polyethylene resin blended with the polyester of the present invention include ethylene homopolymer, ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1, and hexene. 1, other α-olefins having about 2 to 20 carbon atoms such as octene-1 and decene-1, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, unsaturated epoxy And a copolymer with a vinyl compound such as a compound. Specifically, for example, ultra-low / low / medium / high-density polyethylene (branched or linear) ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene- 4-methylpentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer Examples thereof include ethylene resins such as coalescence and ethylene-ethyl acrylate copolymer.

  Examples of the polypropylene resin blended in the polyester of the present invention include propylene homopolymer, propylene, ethylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1, and hexene. -1, octene-1, other α-olefins having about 2 to 20 carbon atoms such as decene-1, vinyl such as vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene Examples thereof include a copolymer with a compound, and a copolymer with a diene such as hexadiene, octadiene, decadiene, dicyclopentadiene, and the like. Specific examples include propylene-based resins such as propylene homopolymer (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymer, propylene-ethylene-butene-1 copolymer.

Moreover, as alpha-olefin resin mix | blended with the polyester of this invention, the homopolymer of about C2-C8 alpha olefins, such as 4-methylpentene-1, those alpha olefins, ethylene, propylene , Butene-1,3-methylbutene-1, pentene-1, hexene-1, octene-1, decene-1, and other α-olefin copolymers having about 2 to 20 carbon atoms. Specifically, for example, butene-1 homopolymers, 4-methylpentene-1 homopolymers, butene-1-ethylene copolymers, butene-1-propylene copolymers, etc. - methylpentene-1 and C ₂ -C ₁₈ copolymer of α- olefins, and the like.

  Examples of the polyamide resin to be blended with the polyester of the present invention include lactam polymers such as butyrolactam, δ-valerolactam, ε-caprolactam, enantolactam, ω-laurolactam, 6-aminocaproic acid, 11-amino. Polymers of aminocarboxylic acids such as undecanoic acid and 12-aminododecanoic acid, hexamethylene diamine, nonamethylene diamine, decamethylene diamine, dodecane methylene diamine, undecamethylene diamine, 2,2,4- or 2,4,4 -Aliphatic diamines such as trimethylhexamethylenediamine, alicyclic diamines such as 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xylylenediamine Diamine units such as aromatic diamines and Polycondensates with aliphatic dicarboxylic acids such as phosphoric acid, adipic acid, suberic acid and sebacic acid, cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, and dicarboxylic acid units such as aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid , And copolymers thereof, specifically, for example, nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6 / MXD6, nylon MXD6 / MXDI, nylon 6/66, nylon 6/610, nylon 6/12, nylon 6 / 6T, nylon 6I / 6T, etc. Can be mentioned. These resins may be crystalline or amorphous.

Moreover, as a polyacetal resin mix | blended with the polyester of this invention, a polyacetal homopolymer and a copolymer are mentioned, for example. As the polyacetal homopolymer, the density measured by ASTM-D792 is 1.40 to 1.42 g / cm ³ , and the melt flow ratio (MFR) measured at 190 ° C. and load 2160 g is measured by ASTM D-1238. ) Is preferably in the range of 0.5 to 50 g / 10 min.

Moreover, as a polyacetal copolymer, the density measured by the measuring method of ASTM-D792 is 1.38 to 1.43 g / cm ³ , the melt flow ratio measured at 190 ° C. and the load of 2160 g by the measuring method of ASTM D-1238. A polyacetal copolymer having a (MFR) in the range of 0.4 to 50 g / 10 min is preferred. Examples of these copolymer components include ethylene oxide and cyclic ethers.

  In the production of the polyester composition blended with the polyolefin resin or the like in the present invention, the resin such as the polyolefin resin is directly added to the polyester A and / or polyester B so that the content thereof falls within the range. In addition to a conventional method such as a kneading method or a method of adding and melt-kneading as a master batch, the resin is added to the production stage of the polyester A and / or polyester B, for example, at the time of melt polycondensation, immediately after melt polycondensation , Whether it is added directly as a granular material at any stage such as immediately after pre-crystallization, at the time of solid-phase polymerization, immediately after solid-phase polymerization, or after the production stage to the molding stage Alternatively, the polyester A chip and / or the polyester B chip are brought into contact with the resin member under flow conditions. The method is incorporated in a method or after the contact treatment can be by methods such as melt-kneading.

  Here, as a method of bringing the polyester chip into contact with the resin member under flow conditions, it is preferable that the polyester chip is brought into collision contact with the member within the space where the resin member is present. For example, immediately after the melt polycondensation of polyester, immediately after precrystallization, immediately after solid-phase polymerization, etc., at the time of filling and discharging the transport container in the transport stage as a product of polyester chips, etc. When the molding machine is inserted in the chip molding stage, a part of pneumatic transportation piping, gravity transportation piping, silo, magnet catcher magnet part, etc. is made of the resin, or the resin film, sheet, molded body, etc. Or lining the resin, or installing the resin member such as a rod-like or net-like body in the transfer path To include a method of transferring the polyester chips. The contact time of the polyester chip with the member is usually an extremely short time of about 0.01 seconds to several minutes, but a small amount of the resin can be mixed into the polyester.

The acetaldehyde content of the molded article made of the polyester of the present invention is 20 ppm or less, preferably 15 ppm or less, more preferably 13 ppm or less, and further preferably 10 ppm or less.

In addition, the cyclic trimer content of the molded body made of the polyester of the present invention is 0.7% by weight or less, preferably 0.5% by weight or less, preferably 0.4% by weight or less, and more preferably 0.00%. 35% by weight or less. In the case of a heat-resistant bottle, if it exceeds 0.4% by weight, mold contamination during molding becomes severe, which is a problem.

  The polyester of the present invention can be preferably used as a hollow molding, a tray, a packaging material such as a biaxially stretched film, a metal can coating film, a fiber containing a monofilament, and the like. The polyester of the present invention can also be used as one constituent layer such as a multilayer molded body or a multilayer film.

  The polyester of the present invention can be used to form films, sheets, containers, and other packaging materials using commonly used melt molding methods. Moreover, it is possible to improve mechanical strength by extending | stretching the sheet-like material which consists of polyester of this invention at least to a uniaxial direction. The stretched film comprising the polyester of the present invention is a stretched film obtained by injection molding or extrusion molding, and any stretching method of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that is generally used for PET stretching. It is molded using. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.

Below, the concrete manufacturing method about the various uses in the case of PET is demonstrated easily.
In producing a stretched film, the stretching temperature is usually 80 to 130 ° C. Stretching may be uniaxial or biaxial, but biaxial stretching is preferred from the viewpoint of film physical properties. In the case of uniaxial stretching, the stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times. In the case of biaxial stretching, the longitudinal and transverse directions are usually 1.1 to 8 times, respectively. Preferably, it may be performed in a range of 1.5 to 5 times. The vertical / horizontal magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-set to improve heat resistance and mechanical strength. The heat setting is usually performed under tension at 120 to 240 ° C., preferably 150 to 230 ° C., usually for several seconds to several hours, preferably several tens of seconds to several minutes.

  In producing the hollow molded body, a blow molded from the polyester of the present invention is stretch blow molded, and an apparatus conventionally used in blow molding of PET can be used. Specifically, for example, once a preform is formed by injection molding or extrusion molding, the plug part and the bottom part are processed as it is, and then reheated, and then biaxial stretch blow molding such as hot parison method or cold parison method The law applies. The molding temperature in this case, specifically, the temperature of each part of the cylinder of the molding machine and the nozzle is usually in the range of 260 to 300 ° C. The stretching temperature is usually 70 to 120 ° C., preferably 90 to 110 ° C., and the stretching ratio is usually 1.5 to 3.5 times in the longitudinal direction and 2 to 5 times in the circumferential direction. The obtained hollow molded body can be used as it is, but in particular in the case of beverages that require hot filling, such as fruit juice beverages and oolong teas, in general, heat-setting treatment is performed in a blow mold, Used to impart sex. The heat setting is usually performed at 100 to 200 ° C., preferably 120 to 180 ° C. for several seconds to several hours, preferably several seconds to several minutes, under tension by compressed air or the like.

  In addition, in order to impart heat resistance to the plug part, the plug part of the preform obtained by injection molding or extrusion molding is crystallized in a far-infrared or near-infrared heater installation oven, or after the bottle is formed, The stopper is crystallized with the heater.

  The polyester of the present invention can also be used for the production of a stretched hollow molded body by a so-called compression molding method in which a preform obtained by compression molding a melt mass cut after melt extrusion is stretch blow molded. .

  For the polyester of the present invention, known ultraviolet absorbers, antioxidants, acetaldehyde reducing agents, oxygen scavengers, lubricants added from the outside, lubricants precipitated internally during the reaction, mold release agents, nucleating agents as necessary Various additives such as stabilizers, antistatic agents, bluing agents, dyes and pigments may be blended.

  In addition, when the polyester of the present invention is used for a film, in order to improve handling properties such as slipping property, winding property, and anti-blocking property, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, Inorganic particles such as barium sulfate, lithium phosphate, calcium phosphate, and magnesium phosphate, organic salt particles such as terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, divinylbenzene, styrene, acrylic acid, methacrylic acid Inactive particles such as crosslinked polymer particles such as a vinyl monomer of acrylic acid or methacrylic acid alone or a copolymer can be contained.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
The main characteristic value measurement methods will be described below.
The composition and characteristics of the polyesters (1), (2), and (3) are measured after the chips are frozen and ground and mixed thoroughly.

(1) Intrinsic viscosity of polyester (IV)
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. The IV (X) of the polyester was a weighted average value calculated from the IV of the constituent polyester.

(2) Polyethylene glycol content of polyester (hereinafter referred to as [DEG content])
Decomposition with methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.

(3) Polyester cyclic trimer content (hereinafter referred to as “CT content”)
300 mg of the frozen and ground sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, brought to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(4) Acetaldehyde content of polyester (hereinafter referred to as “AA content”)
Sample / distilled water = 1 g / 2 cc of glass ampoule substituted with nitrogen was sealed and subjected to extraction treatment at 160 ° C for 2 hours. After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography. The concentration was expressed in ppm. In addition, the acetaldehyde content of a molded object is sampled from the 2 mm-thick plate (A part of FIG. 1) shape | molded by 290 degreeC setting in the method of (10).

(5) Increasing amount of cyclic trimer at the time of melting polyester (△ CT amount)
A sample was taken from a 3 mm thick plate molded at 280 ° C. by the method of (10), dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours, and then 3 g of the sample was placed in a glass test tube, and a nitrogen atmosphere It is immersed in an oil bath at 290 ° C. for 60 minutes and melted. The amount of increase in cyclic trimer at the time of melting is determined by the following equation.
The cyclic trimer content of the plate was used as the cyclic trimer content before melting.
Increase in cyclic trimer during melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)

(6) Measurement of Fine Content About 0.5 kg of resin, sieve (A) with a mesh size of 5.6 mm according to JIS-Z8801, and sieve with a mesh size of 1.7 mm (diameter) 20 cm) (B) was placed on a sieve combined in two stages, and sieved at 1800 rpm for 1 minute with a swing type sieve shaker SNF-7 manufactured by Terraoka. This operation was repeated and a total of 20 kg of resin was sieved. However, when the fine content is small, the amount of the sample is appropriately changed.

  The fine sieved under the sieve (B) is washed with a 0.1% aqueous cationic surfactant solution, then washed with ion-exchanged water, and filtered through a G1 glass filter manufactured by Iwaki Glass Co., Ltd. It was. These were dried together with a glass filter in a dryer at 100 ° C. for 2 hours, then cooled and weighed. Again, the same operations of washing and drying with ion-exchanged water were repeated to confirm that the weight became constant, and the weight of the glass filter was subtracted from this weight to obtain the fine weight. The fine content is the fine weight / the total resin weight that has been sieved.

(7) Crystallization temperature (Tc1) when the molded body is heated and crystallization temperature (Tc2) when the temperature is lowered
Measured with a differential thermal analyzer (DSC), RDC-220, manufactured by Seiko Electronics Industry Co., Ltd. Use 10 mg of the sample from the center of the 2 mm thick plate of the molded plate (10) below. The temperature was raised at a rate of temperature rise of 20 ° C./minute and held at 290 ° C. for 3 minutes, then the temperature was lowered from 290 ° C. to 240 ° C. at 10 ° C./minute, and further from 240 ° C. to 130 ° C. at 7 ° C./minute. The temperature dropped. The peak temperature of the crystallization peak observed at the time of temperature rise is defined as the crystallization temperature (Tc1) at the time of temperature increase, and the peak temperature of the crystallization peak observed at the time of temperature decrease is defined as the crystallization temperature at the time of temperature decrease.

(8) Density of polyester chip It was measured at 30 ° C. with a density gradient tube of calcium nitrate / water solution.

(9) Haze (Fraction%)
A sample was cut from the molded article (wall thickness 4 mm and 5 mm) of the following (10), and measured with a Nippon Denshoku Co., Ltd. haze meter, model NDH2000.

(10) Molding of Stepped Molding Plate Polyester that has been dried under reduced pressure for about 16 hours at 140 ° C. and 0.1 mmHg or less using a vacuum dryer is shown in FIG. 1 using an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 2 having a gate part (G) as shown in FIG. 2 (thickness of A part = 2 mm, thickness of B part = 3 mm, thickness of C part = 4 mm, thickness of D part = 5 mm, E part of A stepped molded plate having a thickness of 10 mm and a thickness of F portion of 11 mm was injection molded.

Polyester previously dried under reduced pressure using a vacuum dryer DP61 manufactured by Yamato Kagaku was used, and a dry inert gas (nitrogen gas) purge was performed in the molding material hopper to prevent moisture absorption during molding. The plasticizing conditions of the M-150C-DM injection molding machine are as follows: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, cylinder temperature 45 ° C., 250 ° C. from the bottom of the hopper in order, nozzle Including 280 ° C. or 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2g. In this case, the holding pressure is 0.5MPa lower than the injection pressure. It was adjusted.
The upper limit of the injection time and pressure holding time is set to 10 seconds and 7 seconds, respectively, and the cooling time is set to 50 seconds. The total cycle time including the time for taking out the molded product is about 75 seconds.

Although the temperature of the mold is always controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of stable molding is around 22 ° C.
The test plate for evaluating the molded product characteristics was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.
The molding temperature refers to the set temperature of the barrel including the nozzle. A molded plate having a molding temperature of 290 ° C. was used for measuring the AA content of the molded plate.

  2 mm thick plate (A part of FIG. 1) is measured for crystallization temperature (Tc1) at the time of temperature rise, crystallization temperature (Tc2) measurement and AA measurement at the time of temperature drop, and 3 mm thick plate (B part of FIG. 1) is melted. Measurement of the amount of increase in cyclic trimer (ΔCT amount) at the time, 4 mm thick plate (C part in FIG. 1) and 5 mm thick plate (D part in FIG. 1) are used for haze measurement. To do.

(11) Molding of hollow molded body The polyester is dried with a dryer using dehumidified air, and preformed at a resin temperature of 280 ° C. with a M-150C-DM injection molding machine manufactured by each machine manufacturer (wall thickness: about 4.1 mm). Was molded. The surface temperature of the mold when molding is stable is around 22 ° C. The plug portion of this preform was heated and crystallized with a home-made plug portion crystallizer. Next, this preform was biaxially stretched and blown with a LB-01E molding machine manufactured by CORPOPLAST, and then heat-set in a mold set at about 150 ° C. for about 5 seconds to form a container having a capacity of 2000 cc. The stretching temperature was controlled at 100 ° C.

(12) Thermal pressure resistance of hollow molded body The hollow molded body molded in (11) is filled with 2.0 gas volume (GV) contents at 23 ° C and immersed in a 70 ° C warm bath for 30 minutes, and then taken out and hollow molded. The volume change rate of the body was evaluated by comparison with that before the bath immersion.
The volume change rate was obtained from the following equation by measuring the internal volume before and after filling.
The heat and pressure resistance was evaluated from the volume change rate (%) value as follows.
○: 0 ≦ Volume change rate (%) <3
Δ: 3 ≦ Volume change rate (%) <5
×: 5 ≦ volume change rate (%)

Volume change rate (%) = 100 × (content before immersion−content after immersion) / content before immersion

(13) Shape and dimensions of the plug portion of the hollow molded body preform The shape and size of the preform plug portion crystallized in (11) was visually observed and evaluated as follows.
A: Extremely stable dimensional accuracy was obtained.
○: Stable dimensional accuracy was obtained.
X: Insufficient crystallization, poor shape.

(14) Appearance of Hollow Molded Body 100 hollow molded bodies of the above (11) were visually observed and evaluated as follows.
◎: Transparent and no appearance problem △: 1 to 5 hollow moldings with whitened flow pattern or whitened product per 100 hollow molded products ×: Hollow with whitened flow pattern or whitened product per 100 hollow molded products 6 or more compacts

(15) Bulk density of polyester Measured by a method according to JIS K6721.

(15) Polyester sodium content, calcium content, magnesium content About 5 to 10 g of sample was put into a platinum crucible and ashed at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness. Dissolve in This solution was measured by atomic absorption spectrometry.

(16) Silicon content of polyester About 5 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then sodium carbonate is added and dissolved by heating, and dissolved in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma optical emission spectrometer manufactured by Shimadzu Corporation.

(17) Sodium content, calcium content, magnesium content and silicon content in chip cooling water Chip cooling water was collected and filtered through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate was subjected to inductively coupled plasma emission analysis manufactured by Shimadzu Corporation. Measured with an instrument.

(18) Mold stain Evaluation was performed as follows.
○: No mold contamination △: Some mold contamination ×: Mold contamination is severe

(19) Sodium content, calcium content, magnesium content and silicon content of chip cooling water or treated water Chip cooling water is collected and filtered through a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate is manufactured by Shimadzu Corporation. Measurements were made with an inductively coupled plasma emission spectrometer.

(Polyester 1-1 (Pes1-1))
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately and continuously supplied to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The intrinsic viscosity (IV) of the obtained PET resin was 0.53.
The cooling water at the time of chip formation is ion-exchanged water having a sodium content of 0.2 ppm, a calcium content of about 0.1 ppm, a magnesium content of about 0.07 ppm, and a silicon content of about 0.5 ppm. Using.

  After fine removal of this resin, it was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 208 ° C. under a nitrogen atmosphere. . After the solid-phase polymerization, fines were removed by continuous treatment in a sieving step and a fine removal step.

The obtained PET has an intrinsic viscosity of 0.67 deciliter / gram, an acetaldehyde (AA) content of 3.2 ppm, a cyclic trimer content of 0.32% by weight, a sodium content of 0.1 ppm, and a calcium content. Was 0.1 ppm, the magnesium content was 0.05 ppm, the silicon content was 0.7 ppm, the fine content was about 50 ppm, and the chip density was 1.398 g / cm ³ . The properties of the obtained PET are shown in Table-1.

(Polyester 1-2A (Pes1-2A), 1-3 (Pes1-3))
Polyester 1-2A and polyester 1-3 were obtained in the same manner as polyester 1-1 except that the polycondensation catalyst addition amount and the solid phase polymerization time were changed.
The properties of the obtained PET are shown in Table-1. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1.

(Polyester 1-2B (Pes1-2B))
Polyester 1-2A except that water having a sodium content of about 10.0 ppm, a calcium content of about 7.0 ppm, a magnesium content of about 3.0 ppm, and a silicon content of 10.0 ppm is used as cooling water during chip formation. In the same manner as above, it was obtained by melt polycondensation and solid phase polymerization.
The properties of the obtained PET are shown in Table-1. The fine content was about 50 ppm, the sodium content was 4.0 ppm, the calcium content was 7.4 ppm, the magnesium content was 6.0 ppm, and the silicon content was 13.0 ppm.

(Polyester 1-4 (Pes1-4))
The polycondensation catalyst addition amount and the solid phase polymerization time were changed, and as the cooling water during chip formation, the sodium content was about 10.5 ppm, the calcium content was about 7.0 ppm, the magnesium content was about 3.0 ppm, silicon It was obtained by melt polycondensation and solid state polymerization in the same manner as polyester 1-1 except that water having a content of 10.5 ppm was used.
The properties of the obtained PET are shown in Table-1. The fine content was about 50 ppm, the sodium content was 4.3 ppm, the calcium content was 7.9 ppm, the magnesium content was 6.2 ppm, and the silicon content was 13.7 ppm.

(Polyester 1-5 (Pes1-5))
The polycondensation catalyst addition amount was changed, and as the cooling water during chip formation, the sodium content was about 10.5 ppm, the calcium content was about 7.0 ppm, the magnesium content was about 3.0 ppm, and the silicon content was 10. A prepolymer was obtained by melt polycondensation in the same manner as for polyester 1-1 except that 5 ppm of water was used.
The obtained prepolymer was put into a rotary reduced pressure solid phase polymerization apparatus, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then subjected to solid phase polymerization at 215 ° C. After solid-phase polymerization, fines were removed in the sieving step. The properties of the obtained PET are shown in Table-1. The fine content was about 530 ppm, the sodium content was 5.2 ppm, the calcium content was 7.5 ppm, the magnesium content was 5.8 ppm, and the silicon content was 21 ppm.

(Polyester 1-6 (Pes1-6), 1-7 (Pes1-7))
As a polycondensation catalyst, a polyester similar to the polyester 1-1 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol is heat-treated in advance are used. 1-6 and 1-7 were obtained. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1.
The properties of the obtained PET are shown in Table-1.

(Polyester 1-8 (Pes1-8), 1-9 (Pes1-9))
Polyesters 1-8 and 1-9 were obtained in the same manner as polyester 1 except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1.
The properties of the obtained PET are shown in Table-1.

(Example 1-1)
The polyester obtained by blending the above polyester 1-1 and polyester 1-3 pellets at a ratio of 8: 2 was evaluated by the molded plate and hollow molded container obtained by the methods (10) and (11). . The results are shown in Table 2.
The AA content of the molded plate was 10.1 ppm, the haze difference Y was as good as 15.2%, and there was no problem with the heat pressure resistance and appearance of the hollow molded container. The AA content of the hollow molded body was as good as 13.3 ppm.

(Examples 1-2, 1-3, 1-4, 1-5)
Evaluation was carried out in the same manner with the compositions shown in Table 2. The results are shown in Table 2.
All the evaluated characteristics were as good as in Example 1-1.

(Comparative Example 1-1)
As shown in Table 2, the polyester 1-4 of Comparative Example 1-1 was evaluated.
Obviously, the AA content and the haze difference ΔHZ of the molded plate of Comparative Example 1-1 were high, and the appearance of the hollow molded body was poor as compared with the Examples. The AA content of the hollow molded body was as high as 25.0 ppm. The results are shown in Table 2.

(Comparative Example 1-2)
As shown in Table 2, the polyester of Comparative Example 1-2 was evaluated.
Obviously, the AA content and the haze difference Y were high, and the heat resistance and appearance of the hollow molded article were poor as compared with the examples. The results are shown in Table 2.

(Polyester 2-1 (Pes2-1))
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately and continuously supplied to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The intrinsic viscosity (IV) of the obtained PET resin was 0.53.
The cooling water at the time of chip formation is ion-exchanged water having a sodium content of 0.1 ppm, a calcium content of about 0.08 ppm, a magnesium content of about 0.07 ppm, and a silicon content of about 0.6 ppm. Using.

  After fine removal of this resin, it was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 208 ° C. under a nitrogen atmosphere. . After the solid-phase polymerization, fines were removed by continuous treatment in a sieving step and a fine removal step.

The obtained PET had an intrinsic viscosity of 0.70 deciliter / gram, an acetaldehyde (AA) content of 3.4 ppm, a cyclic trimer content of 0.34% by weight, and a density of 1.394 g / cm ³ . .

For water treatment of polyester chips, the apparatus shown in FIG. 3 is used. The raw material chip supply port (1) at the upper part of the treatment tank, the overflow discharge port (2) located at the upper limit level of the treatment water in the treatment tank, and the lower part of the treatment tank A discharge port (3) for the mixture of polyester chips and treated water, treated water discharged from this overflow discharge port, treated water discharged from the treatment tank, and draining discharged from the discharge port at the bottom of the treatment tank Pipe (6) in which the treated water passing through the device (4) is sent again to the water treatment tank via the fine powder removing device (5) whose filter medium is a paper-made continuous filter, and these fine water-removed treated water A tower-shaped treatment tank having an internal capacity of about 50 m ³ and equipped with an adsorption tower (8) for adsorbing acetaldehyde in treated water after fine powder removal, and a new ion-exchanged water introduction port (9). used.

The solid-phase polymerized PET chip is treated to remove fines and film-like substances by an air flow classification process and a vibration sieving process, and then processed at a rate of 50 kg / hour into a water treatment tank controlled at a treatment water temperature of 95 ° C. Water was treated by continuously supplying from the supply port (1) at the upper part of the tank, and continuously with the treated water at a rate of 50 kg / hour as PET chips from the outlet (3) at the lower part of the processing tank. In the introduced water collected before the ion exchange water inlet (9) of the above treatment apparatus, the content of particles having a particle size of 1 to 25 μm is about 1500 particles / 10 ml, the sodium content is 0.03 ppm, and the magnesium content is 0.00. 06 ppm, calcium content is 0.03 ppm, silicon content is 0.12 ppm, and the number of particles of 1 to 40 μm of recycled water after treatment in the filtration device (5) and adsorption tower (8) is about 10,000. Pieces / 10 ml.
After the water treatment, fines and the like were removed in the vibration sieve process and the airflow classification process. The sodium content was 0.05 ppm, the calcium content was 0.07 ppm, the magnesium content was 0.05 ppm, the silicon content was 0.6 ppm, and the fine content was about 100 ppm. The properties of the obtained PET are shown in Table-1.

(Polyester 2-2A (Pes2-2A), 2-3 (Pes2-3))
Polyester 2A and polyester 2-3 were obtained in the same manner as polyester 2-1, except that the amount of polycondensation catalyst added and the solid phase polymerization time were changed.
The properties of the obtained PET are shown in Table-3. The fine content was about 100 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as those of the polyester 2-1.

(Polyester 2-4 (Pes2-4))
The polycondensation catalyst addition amount and the solid phase polymerization time were changed, and as the cooling water during chip formation, the sodium content was about 10.5 ppm, the calcium content was about 7.0 ppm, the magnesium content was about 3.0 ppm, silicon It was obtained by melt polycondensation and solid phase polymerization in the same manner as for polyester 2-1, except that water having a content of 10.5 ppm was used. Water treatment was not performed.
The properties of the obtained PET are shown in Table-3. The fine content was 100 ppm, the sodium content was 4.3 ppm, the calcium content was 7.9 ppm, the magnesium content was 6.2 ppm, and the silicon content was 13.7 ppm.

(Polyester 2-6 (Pes2-6), 2-7 (Pes2-7))
As a polycondensation catalyst, a polyester similar to the polyester 2-1 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol has been heat-treated in advance are used. 6 and 7 were obtained. The fine content was about 100 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1. The properties of the obtained PET are shown in Table-3.

(Polyester 2-8 (Pes2-8), 2-9 (Pes2-9))
Polyesters 2-8 and 2-9 were obtained in the same manner as polyester 2-1, except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. The fine content was about 100 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1. The properties of the obtained PET are shown in Table-3.

(Example 2-1)
The pellets of the above polyester 2-1 and polyester 2-3 were blended at a ratio of 8: 2, and evaluation was performed using a molded plate and a hollow molded container obtained by the methods (10) and (11). The results are shown in Table 4.
The AA content of the molded plate is 9.2 ppm, the molded plate haze difference ΔHZ is 9.8%, the AA content of the hollow molded body is 10.6 ppm, and the shape and dimensions of the preform plug portion Also, there was no problem with the appearance of the hollow molded container. In addition, in the accelerated test by continuous bottle forming by the method (11), good bottles with less fogging were obtained for both the 10th and 500th bottles.

(Example 2-2, 2-3)
Evaluation was similarly performed according to the composition shown in Table 4. The results are shown in Table 4.
All the evaluated characteristics were good as in Example 2-1.

(Example 2-4)
Phosphoric acid on the chip surface of a mixture of polyester 2-6, 70 parts by weight and polyester 2-7, 30 parts by weight so that the molar ratio (P / Al) of P content to Al content is about 1.5 And evaluated with a molded plate and a hollow molded container in the same manner as in Example 2-1. The results are shown in Table 4. All the evaluated characteristics were as good as in Example 1.

(Example 2-5)
Phosphoric acid on the chip surface of a mixture of polyester 2-8, 70 parts by weight and polyester 2-9, 30 parts by weight so that the molar ratio (P / Al) of P content to Al content is about 1.5 And evaluated with a molded plate and a hollow molded container in the same manner as in Example 2-1. The results are shown in Table 4. All the evaluated characteristics were good as in Example 2-1.

(Example 2-6)
For polyester 2-2 and polyester 2-3 treated with water, linear low-density polyethylene (MI = about 0.9 g / 10 min, density) on a part of the transportation pipe made of SUS304 connected to the transportation container filling step = About 0.923 g / cm ³ ) was transported in transport piping connected with a cylindrical pipe, and contact treatment was performed under flow conditions. After the contact treatment, it was further treated in an airflow classification process. The polyethylene contents were about 8 ppb and about 9 ppb, respectively, Tc1 of the molded plate was 161 ° C. and 164 ° C., and Tc2 was 177 ° C. and 175 ° C., respectively. The polyethylene content was measured by GPC after extraction and concentration from the chip with hot toluene.
A mixture of polyester 2-2 and 30 parts by weight and polyester 2-3 and 70 parts by weight thus treated with polyethylene was molded and evaluated in the same manner as in Example 2. The results are shown in Table 4. All the evaluated characteristics were as good as in Example 2-.

(Comparative Example 2-1)
Similarly, the polyester of Comparative Example 2-1 was evaluated according to the composition shown in Table 4.
Obviously, the AA content of the molded plate of Comparative Example 2-1, the haze difference ΔHZ of the molded plate and the AA content of the hollow molded body are high when compared with the examples, and the shape, dimensions and hollowness of the preform plug portion The appearance of the molded body and mold contamination were also bad. The results are shown in Table 4.

(Polyester 3-1 (Pes3-1))
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately and continuously supplied to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The intrinsic viscosity (IV) of the obtained PET resin was 0.53.

  The cooling water at the time of chip formation is ion-exchanged water having a sodium content of 0.1 ppm, a calcium content of about 0.1 ppm, a magnesium content of about 0.07 ppm, and a silicon content of about 0.5 ppm. Using.

  After fine removal of this resin, it was subsequently crystallized at about 155 ° C. in a nitrogen atmosphere, further preheated to about 200 ° C. in a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 207 ° C. in a nitrogen atmosphere. . After the solid-phase polymerization, fines were removed by continuous treatment in a sieving step and a fine removal step.

Next, a cylindrical pipe made of linear low-density polyethylene (MI = about 0.9 g / 10 minutes, density = 0.923 g / cm ³ ) is attached to a part of the transportation pipe made of SUS304 connected to the container filling process for transportation. The inside of the transport pipe connected to was transported and contacted under flow conditions. After the contact treatment, it was further treated in an airflow classification process. The polyethylene content was about 7 ppb.

The obtained polyester composition (Polyester 1) has an intrinsic viscosity of 0.67 deciliter / gram, an acetaldehyde (AA) content of 3.5 ppm, a cyclic trimer content of 0.34% by weight, and a sodium content of 0. 0.06 ppm, calcium content was 0.08 ppm, magnesium content was 0.06 ppm, silicon content was 0.5 ppm, fine content was about 50 ppm, and chip density was 1.396 g / cm ³ . Properties of the obtained polyester 3-1 are shown in Table-5.

(Polyester 3-2A (Pes3-2A), 3-3 (Pes3-3))
Polyester 3-2A and polyester 3-3 were obtained in the same manner as polyester 3-1, except that the polycondensation catalyst addition amount and the solid phase polymerization time were changed. Both polyethylene contents were about 9 ppb.
The properties of the obtained PET are shown in Table-5. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were the same as those of the polyester 3-1.

(Polyester 3-4 (Pes3-4))
The polycondensation catalyst addition amount and the solid phase polymerization time were changed, and as the cooling water for chip formation, the sodium content was about 8.6 ppm, the calcium content was about 10.4 ppm, the magnesium content was about 3.0 ppm, silicon It was obtained by melt polycondensation and solid state polymerization in the same manner as for polyester 3-1, except that water having a content of 10.5 ppm was used. No polyethylene contact treatment was performed.
The properties of the obtained PET are shown in Table-5. The fine content was about 50 ppm, the sodium content was 4.0 ppm, the calcium content was 7.5 ppm, the magnesium content was 6.0 ppm, and the silicon content was 12.5 ppm.

(Polyester 3-5 (Pes3-5))
The polycondensation catalyst addition amount, the melt polycondensation time, and the solid phase polymerization time are changed, and the sodium content is about 10.0 ppm, the calcium content is about 7.2 ppm, and the magnesium content is about 0.1 ppm as cooling water during chip formation. Polyester 3-5 was obtained by polycondensation in the same manner as polyester 1 except that water having 3.0 ppm and a silicon content of 10.9 ppm was used. No polyethylene contact treatment was performed.
The properties of the obtained polyester composition are shown in Table-5. The fine content was about 50 ppm, the sodium content was 5.7 ppm, the calcium content was 7.2 ppm, the magnesium content was 5.9 ppm, and the silicon content was 13.1 ppm.

(Polyester 3-6 (Pes3-6), 3-7 (Pes3-7))
As a polycondensation catalyst, the reaction is carried out in the same manner as for polyester 3-1 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution obtained by preheating ethylene glycol are used. Polyester 3-6 and 3-7 were obtained by a polyethylene contact treatment. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1. The polyethylene content was about 9 ppb (Pes6) and 10 ppb (Pes7).
The properties of the obtained polyester composition are shown in Table-5.

(Polyester 3-8 (Pes3-8), 3-9 (Pes3-9))
Polyesters 3-8 and 3-9 were reacted and treated with polyethylene in the same manner as polyester 3-1, except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. Got. The fine content was about 50 ppm, the sodium content, the calcium content, the magnesium content, and the silicon content were about the same as polyester 1. Both polyethylene contents were about 10 ppb.
The properties of the obtained polyester composition are shown in Table-5.

(Example 3-1)
The polyester composition obtained by blending the above polyester 3-1 and polyester 3-3 pellets in a ratio of 8: 2 was evaluated by a molded plate and a hollow molded container obtained by the methods (10) and (11). Carried out. The results are shown in Table 6.
The AA content of the molded plate was 10.0 ppm and the haze difference Y was as good as 14.9%, and there was no problem in the shape and size of the preform plug portion and the appearance of the hollow molded container. Further, the AA content of the hollow molded body was as good as 12.8 ppm.

(Examples 3-2, 3-3, 3-4, 3-5)
Similarly, the polyester compositions of Examples 3-2, 3-3, 3-4, and 3-5 were evaluated according to the compositions shown in Table 6. The results are shown in Table 6.
All the evaluated characteristics were as good as in Example 3-1.

(Comparative Example 3-1)
As shown in Table 6, the polyester 3-4 of Comparative Example 3-1 was evaluated.
Obviously, the AA content and the haze difference ΔHZ of the molded plate of Comparative Example 3-1 were high, and the appearance of the hollow molded body was poor as compared with the Examples. The AA content of the hollow molded body was as high as 27.0 ppm. The results are shown in Table 6.

The present invention provides a polyester that can maintain a transparency even when molded at a low temperature, generates a small amount of aldehyde during molding, and gives a molded product having excellent mechanical properties such as pressure resistance when formed into a molded product. provide. In addition, the polyester of the present invention has improved flow characteristics at low temperatures, so there is less distortion during molding, and molded products with excellent heat-resistant dimensional stability, especially large-sized hollow molded products, can be produced efficiently by high-speed molding. The present invention provides a polyester excellent in long-term continuous formability that gives a molded article that has a very good pressure resistance and heat and pressure resistance and that does not stain the mold, and a molded article comprising the same.
The polyester of the present invention can meet high quality requirements in the field of containers, sheets and the like.

Plan view of stepped plate Side view of stepped plate Schematic diagram of water treatment equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material chip supply port 2 Overflow discharge port 3 Drain port of polyester chip and treated water 4 Drainage device 5 Fine removal device 6 Pipe 7 Recycled water and / or ion exchange water introduction port 8 Adsorption tower 9 Ion exchange water introduction port

Claims (6)

A polyester containing at least one element selected from the group consisting of Al, Ge, and Ti as a polycondensation catalyst and having ethylene terephthalate as a main repeating unit, and having an intrinsic viscosity X of 0.62 to 0.88 Deciliter / gram 5 mm thick haze (A) molded at 280 ° C. is 30% or less and 5 mm thick haze (A) molded at 280 ° C. and 4 mm thick molded at 280 ° C. A polyester characterized in that the difference Y in the haze (B) of the molded article and the intrinsic viscosity X of the polyester satisfy the following formula:
Y = A−B ≦ 70−60X
(In the formula, A is the haze (%) of a molded product having a thickness of 5 mm molded at 280 ° C., B is the haze (%) of the molded product having a thickness of 4 mm molded at 280 ° C., and X is the intrinsic viscosity of the polyester (deciliter / gram). ).)   The polyester according to claim 1, wherein the polyester contains 96 mol% or more of ethylene terephthalate units.   3. The polyester according to claim 1, wherein an acetaldehyde content of a molded body obtained by molding the polyester at 290 ° C. is 20 ppm or less.   The polyester according to any one of claims 1 to 3, wherein the content of the cyclic trimer is 0.70% by weight or less.   A polyester molded article obtained by molding the polyester according to claim 1.   The polyester molded body according to claim 5, wherein the polyester molded body is any one of a hollow molded body, a sheet-like material, and a stretched film obtained by stretching the sheet-like material in at least one direction.

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