JP2007138154A - Polyester composition, polyester molded article made thereof and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester composition suppressing the generation of aldehydes such as acetaldehyde in molding, having excellent transparency and little variation of transparency and capable of efficiently producing a blow-molded article having excellent pressure-resistance or high-temperature dimensional stability, especially a blow-molded article having excellent pressure-resistance and high-temperature pressure-resistance by a high-speed molding method and provide a polyester molded article made thereof and a method for producing the composition. <P>SOLUTION: The polyester composition is composed mainly of at least two kinds of polyesters containing ethylene terephthalate as a main repeating unit. The difference of the intrinsic viscosity values of the polyesters is 0.05-0.30 dL/g and the thermal stability of at least one kind of polyester constituting the polyester composition satisfies a specific condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a hollow molded body including beverage bottles, a sheet-like article, a molded article such as a stretched film, and a coating coated on a substrate such as paper or film (hereinafter, these uses are referred to as “ The polyester composition is preferably used as a raw material such as a molded article) and a polyester molded article comprising the polyester composition, in particular, generation of aldehydes such as acetaldehyde at the time of molding is suppressed, and is excellent in transparency and transparency. Hollow molded products with little fluctuation and excellent pressure resistance or pressure resistance and heat-resistant dimensional stability, polyester molded products such as sheet-like products and stretched films, and polyester excellent in transparency, slipperiness and dimensional stability after molding, and polyester The present invention relates to a method for producing a molded body.

  Polyester represented by polyethylene terephthalate and having ethylene terephthalate as a main repeating unit (hereinafter sometimes abbreviated as PET) is excellent in both mechanical and chemical properties. It has a high technical value and is widely used as a fiber, film, sheet, bottle or the like.

  On the other hand, 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 resins, polyester is excellent in mechanical strength, heat resistance, transparency, and gas barrier properties, and as a material for molded articles such as containers for filling beverages such as juices, soft drinks, and carbonated drinks. Is optimal.

  For example, such 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 stretched blow molded to cool it. It can be made into a hollow molded container for beverages, or it can be molded into a heat-resistant or pressure-resistant hollow molded container by heat-treating the preform plug part (crystallization of the plug part) and then stretching blow molding and heat-treating the body part (heat set). It is common. However, when the crystallization of the plug portion is insufficient or the variation in crystallinity is large, the sealing performance with the cap is deteriorated, and the contents may leak.

  In order to solve such problems, in the case of beverages that require hot filling, such as fruit juice beverages, oolong tea and mineral water, the mouthpieces of preforms or molded bottles are heat-treated and crystallized. A method (for example, see Patent Document 1) is common. Such a method, that is, a method of improving the heat resistance by heat-treating the plug portion and the shoulder portion, the time and temperature for the crystallization treatment greatly affect the productivity, and can be processed at a low temperature in a short time. It is preferable that the conversion rate is PET. On the other hand, the body portion is required to be transparent even if heat treatment is performed at the time of molding so as not to deteriorate the color tone of the contents of the bottle, and the mouthpiece portion and the body portion must have contradictory characteristics.

  In the case of PET, in order to solve such a problem of mold contamination, conventionally, a method of reducing the cyclic trimer, which is the main component of the deposit on the mold surface, by solid-phase polymerization in advance (for example, In this method, the cyclic trimer is regenerated when it is remelted and preformed, and its effect is insufficient. Also disclosed are a method of deactivating a catalyst by contacting PET with water (for example, see Patent Document 2) and a PET having a catalyst deactivated by treating with water (for example, see Patent Document 3). Yes. However, even with the above method, the amount of cyclic oligomer produced at the time of melting is reduced and the mold contamination is reduced temporarily. However, the crystallization speed is unstable, the plug portion dimension accuracy is poor, and the shape is whitened. There is a problem that defects such as flow patterns and bubbles are likely to occur, and only bottles with poor transparency can be obtained, and a solution is awaited.

  PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. In addition, PET produced acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the material of the obtained molded body was increased, and the hollow molded body was filled. Affects the flavor and odor of beverages. 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 the reduction of the acetaldehyde content in the beverage container is becoming increasingly important. In addition, for beverage metal cans, for the purposes of process simplification, hygiene, pollution prevention, etc., cans are made using a metal plate whose inner surface is coated with a polyester film containing ethylene terephthalate as the main repeating unit. The method to do 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), AA at the time of molding using a copolyester having a lower melting point A method of reducing the production (for example, see Patent Document 5), a method using a polyester composition in which 0.05 parts by weight or more and less than 1 part by weight of a metaxylylene group-containing polyamide resin is added to 100 parts by weight of the polyester resin (for example, Patent Document 6), a method for reducing the molding temperature as much as possible during thermoforming, a method for reducing the shear stress as much as possible during thermoforming, and the like 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 satisfactory level, and the problem remains unsolved. In addition, a blend of solid-phase polymerized PET and copolymerized polyethylene terephthalate (for example, see Patent Document 7) has been proposed. 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 at the time of molding increases and the resin in the molding machine increases. Since the temperature rises, the thermal decomposition becomes intense, and there is a problem that the generation amount of aldehydes such as acetaldehyde increases, and a solution is desired.

  Various proposals have been made to solve the problems of improvement and stabilization of the crystallization rate. For example, there is a method of adding an inorganic nucleating agent such as kaolin and talc to polyethylene terephthalate (see, for example, Patent Document 8), but these methods are problematic in practical use with the generation of foreign matter and cloudiness.

  Further, a method of adding a treated polyester obtained by pulverizing a polyester molded body obtained by melt molding from the polyester to the raw material polyester (see, for example, Patent Documents 9 and 10), hydrolyzing the polyester and the intrinsic viscosity A particle mixture (for example, Patent Document 11) with polyester reduced by 0.01 to 0.25 dl / g has been proposed. However, these measures require capital investment for the melt molding and pulverization process and the hydrolysis process at 100 ° C or higher, and the quality of the polyester obtained by melt molding is not stable. It is very difficult to obtain a polyester that has a stable crystallization speed and gives a molded article having excellent dimensional stability and transparency of the plug after heat crystallization, which is preferable economically and in quality. It is not a policy.

  Also, a method for producing a container using a composition comprising two kinds of polyesters having different ranges of intrinsic viscosities having a specific range of temperature-rise crystallization temperature and temperature-fall crystallization temperature (see, for example, Patent Document 12) However, it is difficult to produce bottles with excellent transparency and heat resistance by high-speed molding, and there is also a problem in recyclability, such as adversely affecting transparency when used for re-molding used containers.

As described above, depending on the prior art, a polyester composition that has an appropriate crystallization speed and efficiently gives a polyester molded body with a reduced acetaldehyde content by high-speed molding has not yet been obtained, and a solution is awaited. is there.
JP 55-89330 A Japanese Patent Laid-Open No. 3-47830 Japanese Patent Laid-Open No. 3-72524 JP-A-53-73288 Japanese Patent Laid-Open No. 57-16024 Japanese Examined Patent Publication No. 6-6661 JP 58-45254 A JP-A-56-2342 Japanese Patent Laid-Open No. 5-105807 JP-A-6-116392 JP-A-6-116485 Japanese Patent Laid-Open No. 10-287799

  In view of the problems of the conventional methods described above, the present invention is a hollow molded article that is excellent in transparency and has little variation in transparency, and that suppresses the generation of aldehydes such as acetaldehyde and cyclic trimers during molding, Polyester composition that is suitably used as a raw material for moldings such as sheet-like materials and stretched films and coatings on substrates, and hollow moldings that are excellent in pressure resistance or heat-resistant dimensional stability, especially pressure resistance and heat resistance It is an object of the present invention to provide a polyester composition capable of efficiently producing a hollow molded article excellent in pressure resistance by high-speed molding, a polyester molded article comprising the same, and a method for producing the same.

In order to achieve the above object, the polyester composition of the present invention is a polyester composition containing, as a main component, at least two kinds of polyesters having ethylene terephthalate as a main repeating unit, and the intrinsic viscosity IV of the polyester. Difference in the range of 0.05 to 0.30 deciliter / gram, and the thermal stability parameter (TS) of at least one polyester constituting the polyester composition satisfies the following formula (1): Features.
TS ≦ 0.30 (1)
(In the above formula, TS is the intrinsic viscosity IV after 1 g of a polyester resin chip is placed in a glass test tube, vacuum-dried at 130 ° C. for 12 hours, and maintained in a molten state at 300 ° C. for 2 hours in a non-circulating nitrogen atmosphere. Is a value obtained using the following calculation formula.
^{_{TS = 0.245 {[IV] f2}} -1.47 - [IV] i -1.47}
[IV] _i and [IV] _f2 indicate intrinsic viscosities IV (deciliter / gram) before and after the melting test, respectively. )

  The polyester composition of the present invention is capable of being molded at a lower temperature because of improved flowability when melted in an extruder, and further excellent in heat stability and heat oxidation stability. The content of aldehydes such as acetaldehyde can be reduced and the transparency of the molded article can be greatly improved. At the same time, since the orientation during heating and stretching is improved, it is possible to give a stretched molded article having excellent mechanical properties such as elastic modulus and tensile strength and excellent heat fixability. It is beneficially used as a stretched hollow container excellent in pressure.

  In addition, since the molding temperature can be lowered for the same reason, it becomes possible to suppress the production of the cyclic trimer during melt molding, and particularly a small heat-resistant hollow molded body can be efficiently produced by high-speed molding. Therefore, it is possible to provide a polyester composition that is highly productive and excellent in long-time continuous moldability with little contamination of the mold. Moreover, the sheet-like thing excellent in the dimensional stability after shaping | molding can also be given.

  The difference in intrinsic viscosity of the polyester constituting the polyester composition of the present invention is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, and particularly preferably 0.10. ~ 0.20 deciliter / gram. When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the content of aldehyde such as acetaldehyde in the obtained molded product cannot be reduced, and the flavor retention cannot be improved. On the other hand, when the above-mentioned intrinsic viscosity difference exceeds 0.30 deciliter / gram, thickness irregularities, whitened flow patterns, and the like are generated in the obtained molded product, resulting in a problem of poor transparency. Here, when the polyester composition of the present invention is composed of two or more kinds of polyesters, the difference in intrinsic viscosity is the difference in intrinsic viscosity between the maximum polyester and the minimum polyester with respect to the intrinsic viscosity. Hereinafter, the maximum polyester with respect to the intrinsic viscosity is referred to as polyester B, and the minimum polyester is referred to as polyester A.

Further, the thermal stability parameter (TS) of at least one polyester constituting the polyester composition is more preferably 0.25 or less, further preferably 0.20 or less, and particularly preferably 0.15 or less. When the TS of at least one kind of polyester constituting the polyester composition exceeds 0.30, the thermal stability of the polyester composition is poor, so that the decrease in intrinsic viscosity during molding becomes large, and the transparency of the molded article becomes poor. Moreover, since the production | generation of aldehydes, such as acetaldehyde, increases, the objective cannot be achieved. It goes without saying that the thermal stability parameter (TS) of all the polyesters constituting the polyester composition is most preferably 0.30 or less.
Polyesters having different intrinsic viscosities used in the present invention are polyesters produced so that the difference in intrinsic viscosities falls within the scope of the present invention in the melt polycondensation reaction step or the subsequent solid phase polymerization reaction step, or These are polyesters obtained by contact treatment with water under the condition that the intrinsic viscosity does not decrease.

  As other production methods for obtaining polyesters having different intrinsic viscosities, there are a method of hydrolyzing polyester by heat treatment at high temperature with water, a method of melt treatment with an extruder, and the like. However, since the method by hydrolysis is carried out in a solid state, it is very difficult to control the degree of IV reduction, it is difficult to obtain polyester particles having a narrow IV fluctuation range, and particles after hydrolysis treatment Is likely to generate fine powder due to impact during transportation, etc., so that there is a problem that the fluctuation of the transparency and crystallization speed of the molded body when these are used becomes very large. The fluctuation is a big problem. In addition, the method using the melt treatment has problems such as an influence on flavor retention and coloring due to an increase in aldehydes such as acetaldehyde during the treatment. Therefore, the polyester used in the present invention does not include polyester hydrolyzed by a method such as heat treatment under pressure with water or polyester reduced by IV or melt treated to reduce IV.

  In this case, it is preferable that the thermal oxidation stability parameter (TOS) of at least one polyester constituting the polyester composition satisfies the following formula (2).

        TOS ≦ 0.30 (2)

(In the above formula, TOS is obtained by freeze-pulverizing a polyester resin chip to a powder of 20 mesh or less, vacuum-drying it at 130 ° C. for 12 hours, and placing 0.3 g in a glass test tube for 12 hours at 70 ° C. After drying in vacuo, the intrinsic viscosity IV after heating for 15 minutes at 230 ° C. in air dried on silica gel is measured, and is a value determined using the following formula.
TOS = 0.245 {[IV] _f1 ^-1.47- [IV] _i ^-1.47 }

[IV] _i and [IV] _f1 indicate IV (deciliter / gram) before and after the heating test, respectively. )
The thermal oxidation stability parameter (TOS) of at least one polyester constituting the polyester composition is preferably 0.20 or less, more preferably 0.15 or less, and even more preferably 0.10 or less. When the TOS of at least one kind of polyester constituting the polyester composition exceeds 0.30, the thermal oxidation stability of the polyester composition is poor, so that the intrinsic viscosity is reduced during heat drying or molding in the presence of oxygen. The object cannot be achieved because it becomes large and the transparency of the molded article deteriorates and the production of aldehydes such as acetaldehyde increases. Furthermore, it is most desirable that the thermal oxidation stability parameter (TOS) of all the polyesters constituting the polyester composition is 0.30 or less.

  Details of the TS and TOS measurement methods are as described later.

  In this case, the polyester composition contains the following polyester A and polyester B as main components, and the difference between the crystallization temperature when the temperature of polyester A is lowered and the crystallization temperature when the temperature of polyester B is lowered is 20 ° C. It is preferable that it is the polyester composition within.

Polyester A: Polyester having an intrinsic viscosity IV _A of 0.60 to 0.85 deciliter / gram, a crystallization temperature at the time of temperature increase of 140 to 180 ° C. measured by DSC, and a crystallization temperature at the time of temperature decrease of 160 to 200 ° C. .
Polyester B: Polyester having an intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, a crystallization temperature of 140 to 180 ° C. at the time of temperature rise measured by DSC, and a crystallization temperature of 160 to 200 ° C. at the time of temperature fall .

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

  Moreover, as polyester A or polyester B, it is possible to use at least one kind of polyester that falls within the above characteristic range. For example, as polyester A, two kinds of polyesters differing only in IV are used, and as polyester B, one kind is used. It is also possible to use a polyester mixed with the above-described composition ratio using the above polyester.

  Further, the difference between the crystallization temperature when the temperature of the polyester A is lowered and the crystallization temperature when the temperature of the polyester B is lowered is preferably within 18 ° C, more preferably within 15 ° C, and particularly preferably within 10 ° C. When the difference in the crystallization temperature at the time of temperature drop exceeds 20 ° C., the transparency of the obtained molded product becomes very poor, the crystallization speed fluctuation at the time of crystallization of the plug portion becomes large, and the dimensional accuracy is poor. It is a problem. Here, when the polyester composition of the present invention comprises three or more polyesters, the difference in the crystallization temperature at the time of temperature decrease is the value of the polyester having the highest temperature crystallization temperature and the lowest temperature crystallization temperature. The difference with the value of polyester with

The intrinsic viscosity IV _A of polyester A is preferably 0.62 to 0.80 deciliter / gram, more preferably 0.65 to 0.75 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-190 degreeC, More preferably, it is 165-180 degreeC. 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 0.85 deciliter / gram, the effect of reducing acetaldehyde is reduced. Further, when the crystallization temperature at the time of raising the temperature of the polyester A is less than 140 ° C., the transparency of the molded product is deteriorated, and when it exceeds 180 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. If the crystallization temperature of the polyester A when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization rate of the plug portion becomes worse, and if it exceeds 200 ° C., the transparency of the molded article becomes worse.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.90 deciliter / gram, more preferably 0.75 to 0.85 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-190 degreeC, More preferably, it is 165-180 degreeC. 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 0.95 deciliter / gram, heat generation during molding becomes intense, and the effect of reducing acetaldehyde becomes low. Moreover, when the crystallization temperature at the time of raising the temperature of polyester B is less than 140 ° C., the transparency of the molded article is deteriorated. is there. When the crystallization temperature at the time of temperature reduction of polyester B is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 200 ° C., the transparency of the molded article is deteriorated.

  The polyester according to the present invention can be obtained by appropriately adjusting the production method described below. In particular, the crystallization temperature at the time of temperature reduction and the crystallization temperature at the time of temperature rise of these polyesters are the water quality of the cooling water at the time of chip formation of the melt polycondensation polymer, the fine content of each polyester or polyester composition and its properties or It is possible to control the amount of resin such as polyolefin resin in combination as appropriate.

  By using the polyester composition of the present invention having the above properties, molding at a lower temperature is possible, the content of aldehydes such as acetaldehyde is low, the flavor retention is excellent, the transparency is excellent, and the transparent spots. It is possible to obtain a hollow molded body free from the occurrence of a whitened flow pattern or a partially whitened or wrinkled product generated in the molded body. In particular, these effects become significant in the case of a thick stretched molded body such as a bottle.

  In this case, the polyester composition preferably has an acetaldehyde content of 10 ppm or less and a cyclic trimer content of 0.70% by weight or less.

  In this case, it is preferable that the amount of increase in the cyclic trimer when the polyester composition is melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less. Here, the amount of increase in cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is the thickness of 3 mm of the stepped molded plate obtained from the polyester composition by the molding method described in the “Measurement method” section below. It is the value calculated | required about the sample from this plate.

  In this case, it is preferable that the dispersion ratio Mz / Mn of the molecular weight distribution of the polyester composition is 3.90 or more.

  In this case, the polyester composition can be molded into a polyester molded body. The polyester molded body is a preform for a hollow molded body, a sheet-shaped preform, or a preform of these. It can be any one selected from a stretched film formed by stretching the body in at least one direction and a stretch blow hollow molded body.

  The polyester composition of the present invention has low aldehyde content such as acetaldehyde, excellent flavor retention and transparency, low cyclic trimer content, low molecular weight reduction during continuous molding, and generation of mold stains. A small number of molded articles, for example, hollow molded articles, sheet-like articles, stretched films and the like can be provided.

  Moreover, in this case, it can be a coating obtained by melt-extruding the polyester composition on a substrate.

  Furthermore, the polyester composition may be produced by kneading and molding the above polyester composition under the conditions that the molten resin temperature in the molding machine is 260 to 305 ° C. and the melt residence time in the molding machine is 5 to 500 seconds. it can.

  Since the polyester composition of the present invention has improved thermal stability, thermal oxidation stability and flow characteristics, the amount of aldehyde generation such as acetaldehyde during molding and its fluctuation is small, the hue is good, and a molded product is obtained. In particular, it is excellent in mechanical properties such as pressure resistance. In addition, since the polyester composition of the present invention has improved flow characteristics, there is little distortion during molding, and a molded article having excellent heat-resistant dimensional stability, particularly a hollow molded article, can be efficiently produced by high-speed molding, and Further, it is possible to give a molded article having very good pressure resistance and heat-resistant dimensional stability. In addition, a molded body made of a polyester composition can meet high required quality in the field of containers, sheets, and the like, and its manufacturing method is excellent in long-term continuous moldability with less mold contamination.

Hereinafter, embodiments of the polyester composition of the present invention, a polyester molded article comprising the same, and a method for producing the same will be specifically described.
That is, at least two kinds of polyesters constituting the polyester composition of the present invention are each a linear polyester containing 90 mol% or more of ethylene terephthalate units, preferably 93 mol% or more, more preferably 95 mol% or more, Particularly preferred is a linear polyester containing 97 mol% or more.

  When the polyester is a copolymer, the dicarboxylic acid used for copolymerization is isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyru 4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 4,4 '-Diphenylsulfone dicarboxylic acid, aromatic dicarboxylic acid such as 1,3-phenylene dioxydiacetic acid and functional derivatives thereof, oxyacid such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid , Aliphatic dicarboxylic acids such as sebacic acid, succinic acid, glutaric acid, dimer acid and functional derivatives thereof, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid and functional derivatives thereof Etc.

  When the polyester is a copolymer, glycols used for copolymerization include diethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene. Glycols, 2-ethyl-2-butyl-1,3-propanediol, aliphatic glycols such as neopentyl glycol, dimer glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol 1,4-cyclohexane dimethylol, 2,5-norbornane dimethylol and other alicyclic glycols, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyethoxy) Phenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, aromatic glycols such as alkylene oxide adducts of bisphenol A, polyalkylene glycols such as polyethylene glycol and polybutylene glycol Etc.

  Further, when the polyester contains other copolymer component composed of a polyfunctional compound, examples of the acidic component thereof include trimellitic acid and pyromellitic acid, and examples of the glycol component include glycerin and pentaerythritol. be able to. 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.

  At least two kinds of polyesters constituting the polyester composition of the present invention can be basically produced by the conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method as follows.

  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 composition of the present invention will be described by taking polyethylene terephthalate (hereinafter sometimes abbreviated as 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 1.6 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 (5% 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. As the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Ca, Ba, carbonates and Pb , Zn, Sb, 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 a 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 liquid phase 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, at least one compound selected from Ge, Sb, Ti, or Al compounds is preferably used. 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.

The amount of the Ge compound used is 10 to 90 ppm, preferably 13 to 70 ppm, more preferably 15 to 50 ppm as the residual amount of Ge in the polyester. If the residual amount of Ge exceeds 90 ppm, the thermal stability parameter (TS) exceeds 0.30, which is not preferable. On the other hand, if it is less than 10 ppm, the polycondensation time becomes very long, which is a problem in terms of economy.
Examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony.

  The Sb compound is added so that the residual amount of Sb in the produced polymer is in the range of 50 to 300 ppm, preferably 70 to 200 ppm, more preferably 100 to 180 ppm. When the residual amount of Sb exceeds 300 ppm, the thermal stability parameter (TS) exceeds 0.30, the gray becomes worse, and the amount of foreign matter generated increases, which is not preferable. On the other hand, if it is less than 50 ppm, the polycondensation time becomes very long, which is a problem in terms of economy.

  Examples of the Ti compound 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 ammonium oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl succinate, titanyl succinate, titanium trimellitic acid, 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 Compound, composite oxide composed of titanium and silicon or zirconium, reaction product of titanium alkoxide and phosphorus compound, reaction product of titanium alkoxide and aromatic polycarboxylic acid or its acid anhydride and specific phosphorus compound Thing etc. are mentioned. Examples of the Sb compound include antimony trioxide, antimony acetate, antimony tartrate, antimony potassium tartrate, antimony oxychloride, antimony glycolate, antimony pentoxide, and triphenylantimony.

  The amount of Ti compound used is 0.1 to 30 ppm, preferably 0.5 to 10 ppm, more preferably 1 to 5 ppm as the amount of Ti remaining in the polyester. If the amount of Ti remaining exceeds 30 ppm, the thermal stability parameter (TS) exceeds 0.30, and the brown becomes worse, which is not preferable. On the other hand, if it is less than 0.1 ppm, the polycondensation time becomes very long, which is an economical problem.

  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. Organoaluminum compounds and partial hydrolysates thereof, aluminum oxide, etc. That. 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 residual amount of Al in the produced polymer is in the range of 5 to 70 ppm, preferably 8 to 50 ppm, more preferably 10 to 40 ppm. If the Al residual amount exceeds 70 ppm, the thermal stability parameter (TS) exceeds 0.30, and the amount of foreign matter generated becomes very large. On the other hand, if it is less than 5 ppm, the polycondensation time becomes very long, which is economically problematic.

  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.

  In the production of the polyester used in 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 more preferable. preferable. 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.

Furthermore, the polyester used in the present invention may contain a metal compound containing at least one element selected from the group consisting of silicon, zinc, gallium, strontium, zirconium, hafnium, and thallium. 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 can be added at any stage of the polyester formation reaction step.
Moreover, although a cobalt compound can be used for hue improvement, it is 1-10 ppm as a Co residual amount in a production | generation polymer, Preferably it is 2-8 ppm. If the Co residual amount exceeds 10 ppm, the thermal oxidation stability parameter (TOS) exceeds 0.30, which is not preferable.

  Further, 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.

  After the melt polycondensation polyester is obtained as described above, the melt polycondensation polyester is extruded through the pores into at least one of the following (3) to (6), more preferably into cooling water satisfying all, It is preferable that chips are formed into a columnar shape, a spherical shape, a square shape, or a plate shape by a method of cutting with a cooling method, or a method of cutting while cooling with cooling water having the same water quality as described above after being extruded in the atmosphere. .

Na ≦ 1.0 (ppm) (3)
Mg ≦ 1.0 (ppm) (4)
Si ≦ 2.0 (ppm) (5)
Ca ≦ 1.0 (ppm) (6)

  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.

  In order to reduce sodium, magnesium, calcium, and silicon in the cooling water, an apparatus for removing sodium, magnesium, calcium, and silicon is installed in at least one place until the industrial water is sent to the chip cooling process. Also, a filter is installed to remove clay minerals such as silicon dioxide and aluminosilicate particles. Examples of the device for removing sodium, magnesium, calcium, and silicon include an ion exchange device, an ultrafiltration device, and a reverse osmosis membrane device.

  When solid-state polymerization is performed on the polyester that has been chipped while cooling with cooling water that does not satisfy the above-described conditions, foreign matters in the molded body of the polyester obtained under such conditions are caused by impurities in the cooling water. There is also a problem that the product value increases and the flavor value deteriorates and the commercial value is lowered.

  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 performed in an inert gas atmosphere or under reduced pressure at a temperature optimum 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.

  The polyester used in the present invention can be produced by appropriately controlling the type and amount of polycondensation catalyst, melt polycondensation, cooling water quality used for chip formation, solid-state 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 shape of the polyester chip used in the present invention may be any of a cylinder shape, a square shape, a spherical shape or a flat plate shape. 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 average weight (W) 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 (W) of the chips is also preferably 1 to 5 mg / piece. .

  Moreover, it is also preferable to add a hindered phenolic antioxidant to the polyester composition of the present invention. As such a hindered phenol-based antioxidant, a known one may be used. For example, pentaerythritol-tetra extract [3- (3,5-di-tert-butyl-4-hydrate 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5- Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5) -Methyl 3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5- Lis (4-tert-butyl-3-hydroxy-2,6-dimethylbenzene) isophthalic acid, triethylglycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxy 3- (3-tert- Butyl-5-methyl-4-hydroxyphenyl) propionate), 1,6-hexanediol-bis [3- (3,3- (3,5-di-tert-butyl-4-hydroxyphenyl) bropionate), 2 , 2-thio-diethylene-bis [3- (3,5-di-tert-butyl-4-hydroxyph-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3,5-di-tert- Methyl 4-methylbenzyl phosphonate, 3,5-di-tert-butyl-4-hydroxybenzyl phosphonate, phenyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 3,5- Examples include octadecyl di-tert-butyl-4-hydroxybenzylphosphonate and 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

  In this case, the hindered phenol-based oxidation stabilizer may be bonded to the polyester. The amount of the hindered phenol-based oxidation stabilizer in the polyester composition is preferably 1% by weight or less based on the weight of the polyester composition. This is because if it exceeds 1% by weight, it may be colored, and the ability to improve thermal oxidation stability is saturated even if it is added in an amount of 1% by weight or more. Preferably, it is 0.02 to 0.5 weight%. These oxidation stabilizers can be added at any stage from the production process of the polyester used in the present invention to the production process of the polyester composition.

  The acetaldehyde content of the polyester composition of the present invention is desirably 10 ppm or less, preferably 5 ppm or less, more preferably 4 ppm or less. When the acetaldehyde content exceeds 10 ppm, the effect of flavor retention of the content of the polyester molded body from this polyester composition is deteriorated. Further, the lower limit of the acetaldehyde content is preferably 0.1 ppb from the viewpoint of production.

  The content of the cyclic trimer of the polyester composition of the present invention is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, particularly preferably 0.35% by weight. The following is preferable. 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 the content of the cyclic trimer is 0.70% by weight or more, low molecular weight substances such as the sublimated cyclic trimer are frequently clogged in the vent part of the injection molding machine, and stable production cannot be performed. Problems arise. In addition, when a heat-resistant hollow molded article or the like is formed from the polyester composition of the present invention, heat treatment is performed in a heating mold, but when the cyclic trimer content is 0.70% by weight or more. However, the adhesion of the oligomer to the surface of the heated mold is rapidly increased, and the transparency of the obtained hollow molded article is extremely deteriorated.

  The content of diethylene glycol (hereinafter sometimes abbreviated as DEG) copolymerized with the polyester used in the present invention is 1.0 to 7.0 mol% with respect to all glycol components constituting the polyester. It is preferably 1.3 to 5.0 mol%, more preferably 1.5 to 4.0 mol%, and most preferably 1.8 to 3.0 mol%. When the diethylene glycol content exceeds 7.0 mol%, the thermal stability and thermal oxidation stability deteriorate, and it becomes difficult to obtain a polyester having the characteristics of the present invention. As a result, a decrease in molecular weight becomes large at the time of molding, and an increase in acetaldehyde content and formaldehyde content becomes large, which is not preferable. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

  The diethylene glycol is partially produced from ethylene glycol during the polymerization reaction. Therefore, in addition to the case where a predetermined amount of DEG and its ester-forming derivative is used as a polymerization raw material, reaction conditions, additives, etc. are appropriately selected. Only by doing this, the content of the DEG component can be controlled. Examples of the additive include tertiary amines such as triethylamine, tri-n-butylamine and benzyldimethylamine, and quaternary hydroxides such as tetraethylammonium hydroxide, tetrabutylammonium hydroxide and trimethylbenzylammonium hydroxide. A small amount of a basic compound such as ammonium and lithium carbonate, sodium carbonate, potassium carbonate, or sodium acetate can be added to suppress the formation of DEG. On the other hand, if a small amount of an inorganic acid such as sulfuric acid is added to the polymerization raw material, the formation of DEG can be promoted and the content can be increased.

  Further, the free ethylene glycol content and the free diethylene glycol content of the polyester used in the present invention are 40 ppm or less and 15 ppm or less, preferably 30 ppm or less and 10 ppm or less, more preferably 20 ppm or less and 5 ppm or less, respectively. When the free ethylene glycol content exceeds 40 ppm, or when the free diethylene glycol content exceeds 15 ppm, the resulting polyester molded article has a free ethylene glycol content exceeding 50 ppm, or a free diethylene glycol content exceeding 20 ppm. For this reason, the flavor retention of the stretched hollow molded article is deteriorated, which is a problem. Further, the lower limit values of the free ethylene glycol content and the free diethylene glycol content of the polyester used in the present invention are 5 ppm and 1 ppm, respectively, from the viewpoint of economy.

  Polyester having a free ethylene glycol content below the upper limit and a free diethylene glycol content below the upper limit is, for example, subjected to melt polycondensation in the shortest possible time at the lowest possible temperature, from the final reactor to the nozzle pores. In the meantime, it can be obtained by maintaining the molten resin at a low temperature sufficient to maintain the molten state under short-time conditions.

  Further, the difference in crystallization temperature at the time of temperature rise of the polyester constituting the polyester composition of the present invention is within 10 ° C, preferably within 8 ° C, more preferably within 7 ° C, particularly preferably within 5 ° C. Is desirable. When the difference of the crystallization temperature at the time of the said temperature rise exceeds 10 degreeC, the crystallization speed fluctuation | variation of the obtained molded object becomes large. As a result, for example, the variation in crystallinity of the heat-crystallized hollow molded body plug portion is large, resulting in large dimensional variation of the plug portion, resulting in poor capping properties and leakage of contents. Here, when the polyester composition of the present invention comprises two or more kinds of polyesters, the difference in crystallization temperature at the time of temperature increase is the value of the polyester having the highest temperature crystallization temperature and the lowest temperature increase. It represents the difference in the values of polyesters having a time crystallization temperature.

  In addition, the polyester composition 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 remains in at least one polyester constituting the polyester composition. The polycondensation catalyst to be produced can be produced by deactivation treatment. Of course, it is needless to say that it is most desirable that the polycondensation catalyst of all the polyesters is deactivated.

  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 in which the constituent polyester or a polyester composition containing these as a main component is immersed in water, a method in which water is applied to 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 and water vapor or water vapor containing gas are brought into contact with each other, the water vapor or water vapor containing gas or water vapor containing air at a temperature of 50 to 150 ° C., preferably 50 to 110 ° C., is preferably 1 kg of granular polyester. The water vapor is supplied in an amount of 0.5 g or more as water vapor, 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.

  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.

  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. At this time, a phosphorus compound is added to a polyester of a catalyst (for example, Ge, Sb) whose catalytic activity is not greatly decreased by a phosphorus compound, and blended with a polyester of a catalyst (for example, Ti, Al) whose catalytic activity is decreased by a phosphorus compound. Is also preferable. Thereby, it is possible to easily obtain a polyester having a molecular weight increased to a desired molecular weight while containing a phosphorus compound.

  In addition, a transesterification reaction between the polyesters occurs at the time of molding, but by deactivating the polycondensation catalyst, this transesterification reaction can be suppressed, so that the conditions during molding can be made wider.

Further, the dispersion ratio Mz / Mn of the molecular weight distribution of the polyester composition of the present invention is 3.90 or more, more preferably 3.92 or more, most preferably 3.95 or more, and the dispersion ratio Mz / Mn of the molecular weight distribution is If it is less than 3.90, in order to maintain transparency, it is necessary to raise the melting temperature at the time of shaping | molding, and aldehydes, such as acetaldehyde of a molded object, cannot be reduced. Moreover, it exists in the tendency for the intensity | strength of a bottle to fall.
Here, the dispersion ratio Mz / Mn of the molecular weight distribution is a value calculated by Mz / Mn from the number average molecular weight (Mn) and the Z average molecular weight (Mz) obtained by the GPC method. Details are described in the section of measurement method below.

  Examples of a method for increasing the dispersion ratio Mz / Mn of the molecular weight distribution of the polyester composition to 3.90 or more include a method of blending two or more polymers having substantially the same composition with different Z average molecular weights, and an appropriate amount of the polyfunctional compound. Methods such as copolymerization and polymerization conditions (for example, in the case of a continuous polymerization apparatus, increase the residence time or adjust the number of polymerization tanks, etc.) can be raised, and two or more polymers having different molecular weight distributions A blending method is preferred. The blend may be a molten mixture or a dry blend.

  Moreover, the ratio of the average weight (W) of the polyester which comprises the polyester composition of this invention is 1.00-1.30, Preferably it is 1.00-1.28, More preferably, it is 1.00-1.25. Most preferably, it is 1.00-1.20. If the ratio of the average weight exceeds 1.30, aldehydes are generated at the time of molding, which is not preferable because a special nozzle is used to manufacture chips, and it is not preferable. It becomes difficult and low-temperature molding becomes difficult and becomes a problem. In particular, when used for a heat-resistant hollow stretch molded article, if the ratio is out of the range of 1.00 to 1.15, the effect of reducing aldehydes such as acetaldehyde and improving the transparency deteriorates. The blending amount of the polyester A and the polyester B is likely to occur, which causes the transparency and thickness unevenness of the stretched hollow polyester body, which is not preferable.

  Further, the difference in crystallinity of the polyester chips constituting the polyester composition of the present invention is 15% or less, preferably 10% or less, more preferably 8% or less. When the difference in crystallinity exceeds 15%, the difference in meltability between the polyesters is large and the effect of improving the fluidity is deteriorated. As a result, the transparency of the polyester unstretched molded body and stretched hollow molded body can be improved. The effect of reducing the acetaldehyde content is lost, and the blended amount of the polyester tends to occur, which is not preferable because it causes the transparency of the polyester unstretched molded body and the stretched hollow molded body and fluctuations in the acetaldehyde content. . Here, when the polyester composition of the present invention is composed of two or more kinds of polyesters, the difference in crystallinity is the difference in crystallinity between the largest polyester and the smallest polyester with respect to the degree of crystallinity. is there. Here, the crystallinity of the chip is calculated from the density of the chip obtained by the following method.

  The fine content of the polyester composition of the present invention 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. When the blending amount 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, and therefore the shrinkage amount of the plug portion falls within the specified range. Capping is impossible, capping becomes impossible, and the stretched heat-fixing mold for molding the heat-resistant hollow molded container is severely soiled. To obtain a transparent hollow molded container, the mold must be frequently cleaned. On the other hand, when it exceeds 5000 ppm, the crystallization speed becomes faster than necessary and the fluctuation of the speed becomes large. Therefore, in the case of a sheet-like material, the transparency and the surface state are deteriorated, and 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 unstretched molded body for the hollow molded body is whitened, so that normal stretching is impossible. In particular, the fine content of the polyester composition for the hollow molded body is preferably 0.1 to 500 ppm.

  Further, the fine melting point of the polyester used in the present invention is 265 ° C. or less, preferably 263 ° C. or less, more preferably 260 ° C. or less. In the case of containing fine particles having a melting point exceeding 265 ° C., the crystals are not completely melted under the usual melt molding conditions and remain as crystal nuclei. When the hollow molded body plug portion is heated, the crystallization speed is increased, so that the crystallization of the plug portion becomes excessive. As a result, since the amount of shrinkage of the plug portion does not fall within the specified value range, the capping portion of the plug portion becomes defective and the contents may leak. In addition, the preform for hollow molding is whitened, so that normal stretching is impossible, thickness unevenness occurs, the crystallization speed is high, and the transparency of the obtained hollow molded body is deteriorated. Fluctuations also become large. Further, since the obtained sheet-like material is poor in transparency and has a high crystallization rate, normal stretching is impossible, and only a stretched film having large thickness spots and poor transparency can be obtained.

  The melting point of the fine is measured by the following method using a differential scanning calorimeter (DSC), and the melting peak temperature representing the melting point of the fine is one or more melting peaks. In the present invention, when there is one melting peak, the peak temperature is indicated, and when there are a plurality of melting peaks, the highest temperature among the plurality of melting peaks is indicated. The melting peak temperature is referred to as “the highest peak temperature of the fine melting peak temperature”, and is referred to as “fine melting point” in the examples.

  However, when trying to obtain a hollow molding preform or sheet having good transparency and stretchability from a polyester composition containing fines having a melting peak temperature exceeding 265 ° C., 300 ° C. It must be melt molded at these high temperatures. However, at such a high temperature of 300 ° C. or higher, the thermal decomposition of the polyester becomes severe, and a large amount of by-products such as acetaldehyde and formaldehyde are generated. As a result, the flavor of the contents such as molded articles is great. It will have an effect.

  When the polyester composition of the present invention comprises, for example, the above-mentioned polyester A and polyester B, these can be obtained by uniformly mixing them at a predetermined ratio. For example, a method of dry blending the above polyester A and the above polyester B with a tumbler, V-type blender, Henschel mixer, static mixer or the like, and further the dry blended mixture 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.

  Moreover, the polyester composition of the present invention can be blended with polyamide, polyesteramide, a low molecular weight amino group-containing compound, or a hydroxyl group-containing compound as an aldehyde compound trapping material.

  Examples of the polyamide to be blended as the aldehyde compound capturing material include at least one polyamide selected from aliphatic polyamide and partially aromatic polyamide.

  Specific examples of the aliphatic polyamide include nylon 6, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610, nylon 6/66, nylon 6/610, and the like.

  As a preferable example of the partially aromatic polyamide, a structural unit derived from metaxylylenediamine or a mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid is used. A metaxylylene group-containing polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more in the molecular chain.

  Further, the partially aromatic polyamide may contain a structural unit derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range.

  Examples of these polyamides include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, and metaxylylenediamine / adipic acid / isophthalic acid copolymers, metaxylylene. / Paraxylylene adipamide copolymer, metaxylylene / paraxylylene piperamide copolymer, metaxylylene / paraxylylene azelamide copolymer, metaxylylenediamine / adipic acid / isophthalic acid / ε-caprolactam copolymer And metaxylylenediamine / adipic acid / isophthalic acid / ω-aminocaproic acid copolymer.

  In addition, other preferable examples of the partially aromatic polyamide include at least 20 mol% or more of a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid, A polyamide containing 30 mol% or more, particularly preferably 40 mol% or more is preferred.

  Examples of these polyamides include polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, hexamethylene diamine / terephthalic acid / isophthalic acid copolymer, polynonamethylene terephthalamide, polynonamethylene isophthalamide, nonamethylene diamine / terephthalic acid. / Isophthalic acid copolymer, nonamethylenediamine / terephthalic acid / adipic acid copolymer, and the like.

  Other preferable examples of the partially aromatic polyamide include, in addition to at least one acid selected from aliphatic diamine and terephthalic acid or isophthalic acid, lactams such as ε-caprolactam and laurolactam, and amino such as aminocaproic acid. Derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid obtained by using carboxylic acids, aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid, etc. as copolymerization components The polyamide contains at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more in the molecular chain.

  Examples of these polyamides include hexamethylenediamine / terephthalic acid / ε-caprolactam copolymer, hexamethylenediamine / isophthalic acid / ε-caprolactam copolymer, hexamethylenediamine / terephthalic acid / adipic acid / ε-caprolactam copolymer Examples include coalescence.

  Polyester amides include polyester amide produced from terephthalic acid, 1,4-cyclohexanedimethanol and polyethyleneimine, polyester amide produced from isophthalic acid, 1,4-cyclohexanedimethanol and hexamethylenediamine, and terephthalic acid. Polyesteramides made from adipic acid, 1,4-cyclohexanedimethanol and hexamethylenediamine, polyesteramides made from terephthalic acid, 1,4-cyclohexanedimethanol and bis (p-aminocyclohexyl) methane and their A mixture etc. are mentioned.

  The polyamide or polyester amide used preferably has a secondary transition point measured by DSC (differential scanning calorimeter) of 50 to 120 ° C. When the secondary transition point is less than 50 ° C., it is not preferable because it is fused during the drying step or extrusion with the polyester composition, or cannot be quantitatively extruded. Moreover, when exceeding 120 degreeC, when extending | stretching a polyester unstretched molded object, it will not be stretched | uniformly uniformly but a thickness spot etc. will arise and it is not preferable.

  The shape of the polyamide or polyesteramide chip blended in the polyester composition of the present invention may be any of a cylinder shape, a square shape, a spherical shape, a flat plate shape, and the like. The average particle size is usually in the range of 1.0 to 5 mm, preferably 1.2 to 4.5 mm, more preferably 1.5 to 4.0 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 average weight of the chip is practically in the range of 1 to 50 mg / piece.

  Examples of the low molecular weight amino group-containing compound include aliphatic amine compounds such as stearylamine, 1,8-diaminonaphthalate, 3,4-diaminobenzoic acid, 2-aminobenzamide, and 4,4′-diaminodiphenylmethane. And aromatic amine compounds such as melamine, triazine compounds such as benzoguanamine, and amino acids.

  Examples of the hydroxyl group-containing compound include polyvinyl alcohol, ethylene vinyl alcohol polymer, sugar alcohol, and trimethylolpropane.

  These polyamide compounds, low molecular weight amino group-containing compounds, or hydroxyl group-containing compounds may be used alone or in admixture at an appropriate ratio.

  The aldehyde compound capturing material is used, for example, in an amount of 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the polyester composition of the present invention. be able to.

The aldehyde compound capturing material can be blended by adding a predetermined amount of an aldehyde compound capturing material in any reaction stage from the production of a low polymerization degree oligomer of polyester to the production of polyester polymer. For example, the aldehyde compound capture material is added to a reactor such as an esterification reactor or a polycondensation reactor in an appropriate form such as a fine granule, a powder, or a melt, or a reactor for the next step from the reactor. The aldehyde compound-capturing material or a mixture of the polyester and the polyester may be introduced in a molten state into a transportation pipe for the reaction product of the polyester. Furthermore, if necessary, the obtained chip can be subjected to solid phase polymerization in a high vacuum or in an inert gas atmosphere.
It can also be obtained by a method of mixing a polyester composition and an aldehyde compound capturing material by a conventionally known method, or a method of mixing an aldehyde compound capturing material into a mixture of two or more kinds of polyesters. For example, polyamide chips and two types of polyester chips with different IVs are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture once with a single screw extruder, twin screw extruder, kneader, etc. Examples include those obtained by melting and mixing as described above, and those obtained by subjecting chips from the molten mixture to solid phase polymerization in a high vacuum or inert gas atmosphere as necessary.

  Further, a method in which a solution in which the polyamide or the like is dissolved in a solvent such as hexafluoroisopropanol is adhered to the surface of the polyester chip, and the polyester is collided with the member in a space where the polyamide member is present. Examples include a method of attaching the polyamide to the surface of the polyester chip.

  Furthermore, the polyester composition 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 and polyacetal resins. The blending ratio of the resin used in the present invention to the polyester composition 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, it is 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. Leaking, or the unstretched molded body for hollow molded bodies 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, and the stretchability is also deteriorated so that normal stretching is impossible, and only a stretched film with large thickness spots and poor transparency can be obtained. .

Examples of the polyolefin resin blended in the polyester composition of the present invention include a polyethylene resin, a polypropylene resin, and an α-olefin resin. These resins may be crystalline or amorphous.
In the production of the polyester composition containing 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, etc. The method is mixed in a way or after the above 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. The resin member such as a rod-like or net-like body is provided in the transfer path. And the like to, and 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 polyester composition of the present invention can be preferably used as a hollow molded product, a tray, a packaging material such as a biaxially stretched film, a film for covering a metal can, a fiber containing a monofilament, and the like. Moreover, the polyester composition of this invention can be used also as 1 component layers, such as a multilayer molded object and a multilayer film. It can also be used as a base material on which an oxygen barrier film such as carbon or silica is deposited.

  The method for producing a polyester molded body from the polyester composition of the present invention will be briefly described below, but is not limited thereto. The polyester composition of the present invention is formed by using a generally used melt molding method after the moisture content is reduced to about 100 ppm or less, preferably 50 ppm or less by heat drying under reduced pressure or heat drying under an inert gas. A molded body to be a sheet, a container, or other packaging material can be molded. As conditions relating to the production of a polyester preform, the molten resin temperature is 260 to 305 ° C., preferably 262 to 295 ° C., more preferably by heating a barrel, a die, a hot runner or the like of an injection molding machine or an extrusion molding machine. It is important to set the temperature in the range of 265 to 285 ° C. Here, the molten resin temperature refers to a temperature obtained by immediately measuring, for example, a thermocouple thermometer with a resin injected or extruded from a nozzle tip or a die outlet of an injection molding machine or the like.

  In addition, the melt residence time in the molding machine can be set by arbitrarily selecting the shape of the extruder screw, L / D, etc., and the amount of extrusion in the case of extrusion molding, or in the case of injection molding. The cycle time, the metering stroke (screw back amount), etc. are arbitrarily set, and the time is set in the range of 5 to 500 seconds, preferably 10 to 300 seconds, and more preferably 20 to 200 seconds. Here, the melt residence time is a residence time in a state where the resin is melted in the molding machine. Specifically, the melt residence time is a time during which the resin is melted and held in a cylinder in the molding machine and in a hot runner or a die. That is.

  In the case of injection molding, if the melt residence time is t, t is given by the following formula (5).

                t = W × S / P (5)

Here, W: Weight of molten resin (g) in a cylinder and hot runner of an injection molding machine, etc.
S: Molding cycle time (seconds)
P: Molded product weight (g)

  In the present invention, by controlling the molten resin temperature in the range of 260 to 305 ° C. and setting the melt residence time in the range of 5 to 500 seconds, at least two kinds of polyesters mainly composed of ethylene terephthalate are used as the main repeating unit. From a polyester composition containing as a main component, the content of aldehydes such as acetaldehyde is low, the flavor retention is excellent, the transparency is excellent, and the transparent spots (for example, a whitened flow pattern or part generated in a molded product) In this way, it is possible to obtain a preform for a hollow molded body that is free from the occurrence of a typical whitened product or candy-like product and has no problem in the shape of the plug after crystallization. In particular, in the case of a wall-thickened molded article such as a bottle, these effects become significant.

  When the temperature of the molten resin is less than 260 ° C., the torque load of an injection molding machine or the like is large and molding becomes difficult, the obtained preform becomes extremely poor in transparency, and the thickness of the sheet-like material varies. growing. Moreover, when the temperature exceeds 305 ° C., the thermal decomposition becomes intense and the content of aldehyde such as acetaldehyde increases, which is a problem. When the melt residence time is less than 5 seconds, the transparency of the preform is deteriorated due to insufficient melting, and when it exceeds 500 seconds, the transparency of the preform is very good, but aldehydes such as acetaldehyde. The content of is increased, the molding cycle becomes longer, and the productivity of the preform is lowered.

  Here, the polyester preform is an unstretched sheet obtained by melt extrusion molding a polyester, a preform obtained by compression molding a melt mass obtained by melt extrusion molding, or injection molding. It is the preform etc. which are obtained.

  Moreover, it is possible to improve mechanical strength by extending | stretching the sheet-like material which consists of a polyester composition of this invention at least to a uniaxial direction. The stretched film composed of the polyester composition of the present invention is a sheet-like material obtained by injection molding or extrusion molding, and can be any one of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that are usually used for PET stretching. It is molded using a stretching method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.

Below, the specific manufacturing method about the extending | stretching molded object 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 a stretched hollow molded body, a preform molded from the polyester composition 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 305 ° 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, it is generally heat-set in a blow mold and heat resistant. 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 composition 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. Can do.

  The polyester composition of the present invention can also be used as at least one polyester composition constituting a multilayer hollow molded article.

Another application of the polyester composition of the present invention is a film that is laminated on one or both sides of a laminated metal plate. Examples of the metal plate used include tinplate, tin-free steel, and aluminum.
As a laminating method, a conventionally known method can be applied, and it is not particularly limited, but it is preferable to carry out by a thermal laminating method that can achieve organic solvent-free and can avoid adverse effects on the taste and odor of food products due to the residual solvent. In particular, the thermal laminating method by energization processing of a metal plate is particularly recommended. In the case of double-sided lamination, lamination may be performed simultaneously or sequentially.
Needless to say, a film can be laminated to a metal plate using an adhesive.
Moreover, a metal container is obtained by shape | molding using the said laminated metal plate. The method for forming the metal container is not particularly limited. Further, the shape of the metal container is not particularly limited, but is preferably applied to a so-called two-piece can produced by a molding process such as drawing, drawing and ironing, and stretch draw molding. The present invention can also be applied to a so-called three-piece can in which a top cover suitable for filling a food product such as a coffee drink is wrapped to fill the contents.

  In the polyester composition of the present invention, known ultraviolet absorbers, antioxidants, oxygen scavengers, lubricants added from the outside, lubricants precipitated internally during the reaction, mold release agents, nucleating agents, stability Various additives such as an agent, an antistatic agent, a bluing agent, a dye, and a pigment, and a polyamide resin from metaxylylenediamine and adipic acid may be added to improve oxygen permeability.

In addition, when the polyester composition of the present invention is used for a film, in order to improve handling properties such as slipping property, winding property, and blocking resistance, calcium carbonate, magnesium carbonate, barium carbonate, sulfuric acid are included in the polyester. Inorganic particles such as calcium, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, terephthalate, divinylbenzene, styrene, acrylic acid, Inactive particles such as crosslinked polymer particles such as methacrylic acid, acrylic acid, or vinyl monomers of methacrylic acid, alone or as a copolymer, can be contained.
The main characteristic value measuring methods in the present invention will be described below.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
The main characteristic value measurement methods will be described below.

(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 of the polyester composition was a weighted average value calculated from the IV of the constituent polyester.

(2) Thermal stability parameter (TS)
After putting 1g of polyester chip (before melting test; [IV] _i ) into a glass test tube with an inner diameter of about 14 mm and vacuum-drying at 130 ° C. for 12 hours, set in a vacuum line and repeat decompression and nitrogen filling 5 times or more, then 100 mmHg Of nitrogen and sealed in a salt bath at 300 ° C. and maintained in a molten state for 2 hours, then a sample is taken out, freeze-ground and vacuum-dried, IV (after melting test; IV) _f2 ) Was determined using the following formula.
The formula was quoted from a previous report (Ueyama et al .: Journal of Japan Rubber Association Vol. 63, No. 8, 497, 1990).
^{_{TS = 0.245 {[IV] f2}} -1.47 - [IV] i -1.47}

(3) Thermal oxidation stability parameter (TOS)
A polyester resin chip (before melting test; [IV] _i ) is freeze-pulverized to a powder of 20 mesh or less, vacuum-dried at 130 ° C. for 12 hours, and 300 mg of a glass test tube having an inner diameter of about 8 mm and a length of about 140 mm And then vacuum-dried at 70 ° C. for 12 hours, and a IV tube after being heated in a salt bath at 230 ° C. for 15 minutes under dry air with a drying tube containing silica gel attached to the top of the test tube, It calculated | required using the following formula same as said TS. However, [IV] _i and [IV] _f1 indicate IV (deciliter / gram) before and after the heating test, respectively. The freeze pulverization was carried out using a freezer mill (6750 model manufactured by US Specs). After putting about 2 g of resin chip and a dedicated impactor in a dedicated cell, the cell is set in the apparatus, filled with liquid nitrogen and held for about 10 minutes, and then RATE10 (the impactor is about 20 per second). Pulverized for 5 minutes.

TOS = 0.245 {[IV] _f1 ^-1.47- [IV] _i ^-1.47 }

(4) Diethylene 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.

(5) 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, adjusted to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.

(6) Increasing amount of cyclic trimer during melting of polyester (△ CT amount)
A sample was taken from a 3 mm thick plate molded at 280 ° C. in (17), dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours, and then 3 g of the polyester sample was placed in a glass test tube and placed under a nitrogen atmosphere. And soak in an oil bath at 290 ° C. for 60 minutes to melt. The increase amount of the cyclic trimer at the time of melting is obtained by the following equation.
In addition, the cyclic trimer content before melting was a weighted average value of the cyclic trimer content of the polyester constituting the polyester composition.

Increase amount of cyclic trimer at the time of melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)

(7) 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 the case of a hollow molded body, a sample was taken from the mouth. In the case of molding the dry blend composition, the average value of the AA contents of the individual polyesters was used as the AA content of the polyester composition before molding.

(8) Density (ρ) and crystallinity (CR) of polyester chip
The density (ρ) of the chip at 30 ° C. was measured with a density gradient tube of calcium nitrate / water solution.
In the case of PET, the crystallinity was calculated from the following formula.

CR = 100ρ _c (ρ−ρ _a ) / ρ (ρ _c −ρ _a )

Where ρ is the density of the chip
ρ _a : amorphous density (1.335 g / cm ³ )
ρ _c : crystal density (1.455 g / cm ³ )

(9) Average weight (W) of polyester chip and ratio of average weight (W _A / W _B )
After removing fines with ion-exchanged water, the weight of 100 dried polyester chips was measured, and the average value was defined as the average weight (W). When the polyester composition is a mixture of two kinds of polyesters, the ratio of the average weight of the polyester chips between the two kinds (W _A / W _B ) is the average weight of the polyester chips having a larger average weight among the two kinds. and W _a, the average weight of the average weight of small polyester chips as _{W B,} was calculated _W a / W _B. When the two types of polyester chips have the same average weight, W _A / W _B is 1.00. Moreover, when it consists of 2 or more types of polyester, it calculates as mentioned above for 2 types of polyester with many mixing ratios.
In this case, the selection of 100 chips was performed by excluding abnormally sized chips. The specific chip exclusion method is as follows.
In calculating the average weight (W) of the chips, 100 chips were randomly selected, and after calculating the average weight (W), the chips having a weight of less than 0.5 W and the chips having a weight of more than 2 W were excluded and excluded. A number of chips were picked again at random, replenished and 100 averages recalculated. This was done until all 100 chips were within 0.5W-2W.

(10) Sodium content and calcium content of polyester About 5 to 10 g of a sample is put in a platinum crucible and incinerated at about 550 ° C., then dissolved in 6N hydrochloric acid and evaporated to dryness, and the residue is dissolved in 1N hydrochloric acid. This solution was measured by atomic absorption spectrometry.

(11) 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 emission spectrometer manufactured by Shimadzu Corporation.

(12) 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 operation of washing and drying with ion-exchanged water was 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.

(13) Measurement of fine melting peak temperature (hereinafter referred to as “fine melting point”) Measured using a differential scanning calorimeter (DSC) manufactured by Seiko Denshi Kogyo Co., Ltd., RDC-220. In (12), the fine material collected from 20 kg of polyester was frozen and ground and mixed, and then dried under reduced pressure at 25 ° C. for 3 days. From then on, 4 mg of sample was used for one measurement, and the heating rate was 20 ° C./min. DSC measurement is performed to obtain the melting peak temperature on the highest temperature side of the melting peak temperature. The measurement is performed on a maximum of 10 samples, and the average value of the melting peak temperatures on the highest temperature side is obtained. If there is a single melting peak, the temperature is determined.

(14) 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) manufactured by Seiko Denshi Kogyo Co., Ltd., RDC-220. Using 10 mg of a sample from the center of a 2 mm thick plate of the molded plate (17) below. The temperature was raised at a rate 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 (Tc2).

(15) Haze (degree of haze) and haze spots A sample was cut from the molded product (thickness 5 mm) of the following (17) and measured with a Nippon Denshoku haze meter, model NDH2000. Moreover, the haze of the molded board (thickness 5 mm) shape | molded continuously 50 times was measured, and the haze spot was calculated | required by the following.

      Haze spots = maximum value of haze / minimum value of haze

  In addition, the haze of the stretched hollow molded body was measured with a haze meter, model NDH2000, manufactured by Nippon Denshoku Co., Ltd., by cutting a sample from the bottle body of (18) below.

(16) Number average molecular weight Mn, Z average molecular weight Mz and molecular weight distribution dispersion ratio Mz / Mn
The number average molecular weight Mn and the Z average molecular weight Mz were determined by the GPC method using fine particles obtained by freeze-pulverizing about 10 grams of the polyester composition as a sample. The measurement was performed 3 times and obtained as an average value.

(Preparation of sample) 1 mg of a sample was dissolved in 0.2 ml of chloroform / hexafluoroisopropanol = 3/2 (vol%), and then diluted with 3.8 ml of chloroform to prepare a sample solution.

(Eluent) Chloroform / hexafluoroisopropanol = 98/2 (vol%)
(Apparatus) TOSOH HLC-8220GPC manufactured by Tosoh Corporation was used.
(Column) TSKgel SuperHM-H × 2 + manufactured by Tosoh Corporation
TSKgel SuperH2000
(Standard polystyrene) TSK standard polystyrene manufactured by Tosoh Corporation was used.
(Measurement conditions) Measurement temperature 40 ° C., flow rate 0.6 ml / min (detector) UV detector 254 nm
(Molecular weight conversion) Calculation was performed in terms of standard styrene.
(Integration range 1) Peak start with standard polystyrene, peak rise point,
The peak end was 700 with standard polystyrene.

The dispersion ratio Mz / Mn of the molecular weight distribution was determined from the following.
Dispersion ratio of molecular weight distribution = Mz / Mn

(17) Molding of stepped molded plate
The polyester dried for about 8 hours at 140 ° C. using a dryer with heated dehumidified air is transferred to a gate part (M-150C-DM type injection molding machine manufactured by Meiki Seisakusho Co., Ltd. as shown in FIGS. 1 and 2). G) 2 mm to 11 mm (A part thickness = 2 mm, B part thickness = 3 mm, C part thickness = 4 mm, D part thickness = 5 mm, E part thickness = 10 mm, F part thickness = 11 mm) A stepped molding plate having a thickness of 2) was injection molded.

  In order to prevent moisture absorption during molding, a dry inert gas (nitrogen gas) purge was performed in the molding material hopper. The plasticizing conditions of the M-150C-DM injection molding machine are: 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 molding temperature refers to the set temperature of the barrel including the nozzle.
The stepped molded plates used for the measurement of various polyester molded plates Tc1 and Tc2 used in Examples and Comparative Examples are molded plates molded at a molding temperature of 290 ° C.
Moreover, the molded board of 280 degreeC shaping | molding temperature was used for the measurement of the molded board haze (%) and molded board haze spot (%) of the polyester composition in an Example and a comparative example.
The test plate for evaluating the characteristics of the molded product 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.
A 2 mm-thick plate (part A in FIG. 1) measures the crystallization temperature (Tc1) at the time of temperature rise and a crystallization temperature (Tc2) at the time of the temperature drop, and a 5 mm-thick plate (part D in FIG. %) Used for measurement.

(18) Molding of hollow molded body 1) Molding of preform Using a polyester chip dried at 140 ° C for about 8 hours using a dryer with heated dehumidified air, molding is performed to prevent moisture absorption of the chip during molding. The material hopper was purged with a dry inert gas (nitrogen gas).

  Plasticizing conditions by M-150C-DM injection molding machine manufactured by Meiki Seisakusho Co., Ltd. are as follows: feed screw rotation speed = 70%, screw rotation speed = 120 rpm, back pressure 0.5 MPa, weighing position 50 mm, cylinder temperature from directly under the hopper In order, the temperature was set to 45 ° C., 250 ° C., and thereafter the molten resin temperature including the nozzle was 280 ° C. The injection conditions were such that the injection speed and holding pressure were 10%, and the injection pressure and holding pressure were adjusted so that the weight of the molded product was 58.6 ± 0.2 g. Adjusted to 5 MPa lower. The cooling time is set to 20 seconds, the entire cycle time including the molded product taking time is about 42 seconds, and the melt residence time is about 100 seconds. The preform has an outer diameter of 29.4 mm, a length of 145.5 mm, and a wall thickness of about 3.7 mm.

  The mold is always controlled by introducing cooling water having a water temperature of 18 ° C., but the mold surface temperature at the time of molding stability is around 29 ° C. The preform for property evaluation was arbitrarily selected from stable molded products 20 to 50 shots after the start of molding after introducing the molding material and replacing the resin.

2) Molding of stretched hollow molded body (bottle) The plug portion of the preform was heated and crystallized with a home-made plug portion crystallization apparatus. Next, this preform was biaxially stretched and blown at a magnification of about 2.5 times in the longitudinal direction and about 3.8 times in the circumferential direction on an LB-01E molding machine manufactured by CORPOPLAST, and subsequently set at about 145 ° C. It was heat-set in the mold for 7 seconds to mold a 1500 cc container (trunk thickness 0.45 mm). The stretching temperature was controlled at 100 ° C. and arbitrarily selected from the stable molded products on the 10th to 30th shots from the start of molding. A sample was taken from the mouth of the bottle and used for measurement of acetaldehyde content (AA content) and cyclic trimer content (CT content).

(19) Strength measurement of the bottle body The bottle body molded by the above method is cut into large pieces with a cutter, punched with a super dumbbell cutter model SDMK-1000D dumbbell (according to JISK-7162-5A), and a tensile tester The strength was measured using SS-207D-U (manufactured by Toyo Baldwin).

(20) Appearance of Hollow Molded Body Twenty hollow molded bodies from the tenth molding start of (18) were visually observed and evaluated as follows.
◎: Transparent and no appearance problem △: There is a little whitened flow pattern or whitened product in the hollow molded body ×: Whitened flow pattern or whitened product in the hollow molded body

(21) Shape and size of plug part of unstretched molded body for hollow molded body The shape and dimension of the unstretched molded body plug part crystallized in (18) were visually observed and evaluated as follows.
A: Extremely stable dimensional accuracy was obtained.
○: Stable dimensional accuracy was obtained.
X: Insufficient crystallization, poor shape, or excessive crystallization, poor dimensionality.

(22) Sodium content, magnesium content, calcium 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 supplied by Shimadzu Corporation. Measurement was performed with an inductively coupled plasma emission spectrometer.

(Polyester 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 under stirring. Reaction was performed. Further, 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 supplied continuously 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 for 1 hour at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The number average molecular weight of the obtained PET was 13,000, the intrinsic viscosity (IV) was 0.53, and the DEG content was 2.5 mol%. As cooling water at the time of chip formation, ion-exchanged water having a sodium content of 0.1 ppm, a calcium content of about 0.2 ppm, a magnesium content of about 0.04 ppm, and a silicon content of about 0.6 ppm is used. Using.

  The resin was subsequently crystallized in a nitrogen atmosphere at about 155 ° C., 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 206 ° 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.

The obtained PET had an intrinsic viscosity of 0.70 deciliter / gram, an acetaldehyde (AA) content of 3.5 ppm, a cyclic trimer content of 0.34% by weight, a chip crystallinity of 56.3%, TS Is 0.15, TOS is 0.20, chip average weight (W) is 24.7 mg, sodium content is 0.02 ppm, calcium content is 0.05 ppm, silicon content is 0.06 ppm, fine content is About 50 ppm and the fine melting point was 250 ° C. Further, the Ge residual amount measured by atomic absorption analysis was about 40 ppm, and the P residual amount was about 21 ppm.
The properties of the obtained PET are shown in Table-1.

(Polyester 2, 3)
Polyesters 2 and 3 were obtained by reacting in the same manner as polyester 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-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Further, the residual amount of Ge of polyester 2 was about 51 ppm, the residual amount of P was about 26 ppm, the residual amount of Ge of polyester 3 was about 43 ppm, and the residual amount of P was about 23 ppm.

(Polyester 4, 5)
Increase the amount of polycondensation catalyst added, change the solid-state polymerization conditions, and further, as the cooling water during chip formation, sodium content is about 10.0 ppm, calcium content is about 12.5 ppm, magnesium content is about 5.0 ppm Polyesters 4 and 5 were produced in the same manner as Polyester 1 and Polyester 2 except that water having a silicon content of 12.0 ppm was used.
The properties of the obtained PET are shown in Table-1. The sodium content was 5.0 ppm, the calcium content was 5.8 ppm, and the silicon content was 6.0 ppm. Further, the residual amount of Ge of polyester 4 was about 98 ppm, the residual amount of P was about 35 ppm, the residual amount of Ge of polyester 5 was about 110 ppm, and the residual amount of P was about 40 ppm.

(Polyester 6)
A prepolymer was obtained by melt polycondensation in the same manner as polyester 1 except that the amount of polycondensation catalyst added was changed. The resulting prepolymer was finely removed and then charged into a rotary vacuum solid-phase polymerization apparatus, and crystallized at 70 to 160 ° C. under reduced pressure while rotating, followed by 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. Sodium content, calcium content, and silicon content were similar to those of polyester 1. The residual amount of Ge was about 60 ppm, and the residual amount of P was about 32 ppm.

(Polyester 7, 8)
As a polycondensation catalyst, the same procedure as for polyester 1 or polyester 2 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 preheated is used. By reacting, polyesters 7 and 8 were obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. The residual amount of Al was about 20 ppm and the residual amount of P was about 15 ppm.

(Polyester 9, 10)
As a polycondensation catalyst, an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used and reacted in the same manner as polyester 1 or polyester 2 except that phosphoric acid was not added. Obtained. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Further, the residual amount of Ti in polyester 9 was about 4 ppm, the residual amount of Mg was about 4 ppm, the residual amount of Ti in polyester 10 was about 6 ppm, and the residual amount of Mg was about 6 ppm.

(Polyester 11, 12)
Polyesters 11 and 12 were obtained by reacting in the same manner as Polyester 9 or Polyester 10 except that the amount of polycondensation catalyst titanium tetrabutoxide was increased and cobalt acetate tetrahydrate was used in combination. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Further, the residual amount of Ti in polyester 11 was about 33 ppm, the residual amount of Co was about 10 ppm, the residual amount of Ti in polyester 12 was about 35 ppm, and the residual amount of Co was about 10 ppm.

(Polyester 13, 14)
Polyesters 13 and 14 were obtained by reacting in the same manner as polyester 1 or polyester 2, except that an ethylene glycol solution of antimony trioxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Polyester 13 had an Sb residual amount of about 195 ppm, an Mg residual amount of about 20 ppm, and a P residual amount of about 20 ppm. Polyester 14 had an Sb residual amount of about 210 ppm, an Mg residual amount of about 22 ppm, and a P residual amount of about 25 ppm. .

(Polyester 15)
Polyester 15 was obtained by reacting in the same manner as polyester 13 or polyester 14 except that the amount of antimony trioxide added to the polycondensation catalyst was increased and cobalt acetate tetrahydrate was used in combination. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Polyester 15 had an Sb residual amount of about 380 ppm, a Co residual amount of about 30 ppm, and a P residual amount of about 30 ppm.

(Polyester 16)
The polyester 1 is continuously treated from the supply port (1) at the upper part of the treatment tank at a rate of 50 kg / hour to the following water treatment tank controlled at a treatment water temperature of 95 ° C., and discharged at the lower part of the treatment tank. From (3), a PET chip was continuously extracted with treated water at a rate of 50 kg / hour. The introduced water sampled before the ion exchange water inlet (9) of the water treatment apparatus has a particle content of 1 to 25 μm in diameter of about 1000 particles / 10 mL, a sodium content of 0.04 ppm, and a magnesium content of 0.1. 05 ppm, calcium content 0.05 ppm, silicon content 0.12 ppm, and the number of particles of recycled water having a particle size of 1 to 40 μm 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 same manner as polyester 1.

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 chip and treated water, treated water discharged from the overflow discharge port, treated water discharged from the treatment tank, and draining device discharged from the discharge port at the bottom of the treatment tank ( 4) The treated water passed through 4) is again sent to the water treatment tank via the fine powder removing device (5) whose filter medium is a paper-made continuous filter, and these fine powder removed treated water. Uses an inlet (7), an adsorption tower (8) for adsorbing acetaldehyde in treated water from which fine particles have been removed, and a tower-type treatment tank with an internal capacity of about 50 m ³ equipped with a new ion-exchange water inlet (9) did.
The properties of the obtained PET are the same as the properties of polyester 1 described in Table 1, except that the amount of increase in cyclic trimer (ΔCT amount) upon melting is 0.10% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 17)
Polyester 2 was treated with water in the same manner as described above to obtain polyester 17.
The properties of the obtained PET are the same as the properties of polyester 2 described in Table 1, except that the cyclic trimer increase amount (ΔCT amount) upon melting is 0.10% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 1.

(Polyester 18)
In the first esterification reactor, a slurry of high-purity terephthalic acid (corresponding to 98.0 mol% of the total acid component), isophthalic acid (2.0 mol% of the total acid component) and ethyl glycol are continuously added. A polyester 18 was obtained by reacting in the same manner as in the polyester 1 except that it was supplied. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Further, the residual amount of Ge of polyester 1 was about 42 ppm, and the residual amount of P was about 23 ppm.

(Polyester 19)
In the first esterification reactor, a slurry of high-purity terephthalic acid (corresponding to 98.0 mol% of the total acid component), isophthalic acid (2.0 mol% of the total acid component) and ethyl glycol are continuously added. A polyester 19 was obtained by reacting in the same manner as in the polyester 2 except that it was supplied. The properties of the obtained PET are shown in Table-1. Sodium content, calcium content, and silicon content were similar to those of polyester 1. Further, the residual amount of Ge of polyester 2 was about 49 ppm, and the residual amount of P was about 26 ppm.

(Polyamide 1)
Toyobo nylon MXD6 resin (T600) manufactured by Toyobo Co., Ltd. was used.

Example 1
A polyester composition obtained by blending the above-mentioned polyester 1 and polyester 2 pellets in a ratio of 7: 3 is obtained by molding at 290 ° C. by the method (17) and by injection molding by the method (18). Evaluations were made on hollow molded containers. The results are shown in Table 2.
The shape and dimensions of the unstretched molded body plug part after crystallization are not a problem. The stretched hollow molded body has an AA content of 8.3 ppm, a cyclic trimer content of 0.35% by weight, and a haze of 1.2%. There was no problem with the value.

(Example 2)
Using the water-treated PET mixture, the polyester composition of Example 2 was evaluated in the same manner as in Example 1 with the composition shown in Table 2. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1. Further, the amount of increase in cyclic trimer (ΔCT amount) at the time of melting of the compact was as low as 0.10% by weight.

(Example 3)
Evaluation was carried out in the same manner as in Example 1 for the polyester composition of Example 3 in which 1,70 parts by weight of polyester, 2,30 parts by weight of polyester and 1.1 parts by weight of polyamide were blended. The results are shown in Table 2. The stretched hollow molded article had a low AA content of 5.1 ppm, a good haze of 1.6%, and other characteristics were satisfactory.

(Comparative Example 1)
As shown in Table 2, the polyester 3 of Comparative Example 1 was evaluated in the same manner as in Example 1. Obviously, the shape and dimensions after crystallization of the unstretched molded body plug portion were poor as compared with the examples, and the AA content and haze value of the stretched hollow molded body were high, which was a problem. The results are shown in Table 2.

(Comparative Example 2)
As shown in Table 2, the polyester composition of Comparative Example 2 was evaluated. Obviously, the shape and dimensions after crystallization of the unstretched molded body plug portion were poor as compared with the examples, and the AA content and haze value of the stretched hollow molded body were high and problematic. The results are shown in Table 2.

(Comparative Example 3)
As shown in Table 2, the polyester composition of Comparative Example 3 was evaluated. Obviously, the shape and dimensions after crystallization of the unstretched molded body plug portion were poor as compared with the examples, and the AA content and haze value of the stretched hollow molded body were high and problematic. The results are shown in Table 2.

Example 4
Evaluation was carried out in the same manner as in Example 1 for the polyester composition of Example 4 in which the above polyester 7,70 parts by weight and polyester 8, 30 parts by weight were blended. The results are shown in Table 3. The stretched hollow molded article had a low AA content of 8.0 ppm, a good haze of 1.2%, and other characteristics were satisfactory.

(Example 5)
Evaluation was carried out in the same manner as in Example 1 for the polyester composition of Example 5 in which 9,70 parts by weight of the above polyester and 10, 30 parts by weight of the polyester were blended. The results are shown in Table 3. The stretched hollow molded article had a low AA content of 10.5 ppm, a good haze of 1.2%, and other characteristics were satisfactory.

(Example 6)
Evaluation was carried out in the same manner as in Example 1 for the polyester composition of Example 6 in which the above polyester 13,70 parts by weight and polyester 14,30 parts by weight were blended. The results are shown in Table 3. The stretched hollow molded article had a low AA content of 9.8 ppm, a haze of 1.5%, and other characteristics were satisfactory.

(Example 7)
Evaluation was carried out in the same manner as in Example 1 with respect to the polyester composition of Example 7 in which the above-mentioned polyester 18,70 parts by weight and polyester 19,30 parts by weight were blended. The results are shown in Table 3. The stretched hollow molded article had a low AA content of 7.5 ppm, a good haze of 1.1%, and other characteristics were satisfactory.

(Comparative Example 4)
As shown in Table 3, the polyester composition of Comparative Example 4 was evaluated. Obviously, the shape and dimensions after crystallization of the unstretched molded body plug portion were poor as compared with the examples, and the haze value of the stretched hollow molded body was high and problematic. The results are shown in Table 3.

(Comparative Example 5)
As shown in Table 3, the polyester composition of Comparative Example 5 was evaluated. Obviously, the shape and dimensions after crystallization of the unstretched molded body plug portion were poor as compared with the examples, and the haze value of the stretched hollow molded body was high and problematic. The results are shown in Table 3.

  As mentioned above, although the polyester composition of this invention, the polyester molded object, and its manufacturing method were demonstrated based on the several Example, this invention is not limited to the structure described in the said Example, Each Example The configuration can be changed as appropriate without departing from the spirit of the invention, for example, by appropriately combining the configurations described in (1).

  Since the polyester composition of the present invention has improved flow characteristics, it has excellent transparency and little variation in transparency, and the amount of aldehyde generated during molding and its variation is small. In addition, the polyester molded body of the present invention and the method for producing the same use a polyester composition having such characteristics. Highly heat-resistant dimensional stability molded products with low distortion and moderate crystallization speed, especially hollow molded products can be efficiently produced by high-speed molding, and the mold is not contaminated for a long time. It can be used for applications where moldability is required.

Plan view of stepped plate Side view of stepped plate Schematic of the water treatment equipment used in the examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material chip supply port 2 Overflow discharge port 3 Discharge 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 (10)

A polyester composition comprising, as a main component, at least two kinds of polyesters mainly composed of ethylene terephthalate, wherein the difference in intrinsic viscosity of the polyesters is in the range of 0.05 to 0.30 deciliter / gram. A polyester composition wherein the thermal stability parameter (TS) of at least one polyester constituting the polyester composition satisfies the following formula (1).
TS ≦ 0.30 (1)
(In the above formula, TS is obtained by putting 1 g of a polyester resin chip in a glass test tube, vacuum-dried at 130 ° C. for 12 hours, and then maintaining the intrinsic viscosity after being maintained in a molten state at 300 ° C. for 2 hours in a non-circulating nitrogen atmosphere. It is a value obtained by measurement and using the following calculation formula.
^{_{TS = 0.245 {[IV] f2}} -1.47 - [IV] i -1.47}
[IV] _i and [IV] _f2 indicate intrinsic viscosities (deciliter / gram) before and after the melting test, respectively. ) The polyester composition according to claim 1, wherein the thermal oxidation stability parameter (TOS) of at least one polyester constituting the polyester composition satisfies the following formula (2).
TOS ≦ 0.30 (2)
(In the above formula, TOS is obtained by freeze-pulverizing a polyester resin chip to a powder of 20 mesh or less, vacuum-drying it at 130 ° C. for 12 hours, and placing 0.3 g in a glass test tube for 12 hours at 70 ° C. After drying in vacuo, the intrinsic viscosity IV after heating for 15 minutes at 230 ° C. in air dried on silica gel is measured, and is a value determined using the following formula.
TOS = 0.245 {[IV] _f1 ^-1.47- [IV] _i ^-1.47 }
[IV] _i and [IV] _f1 indicate intrinsic viscosities (deciliter / gram) before and after the heating test, respectively. ) The polyester composition contains the following polyester A and polyester B as main components, and the difference between the crystallization temperature when the temperature of polyester A is lowered and the crystallization temperature when the temperature of polyester B is lowered is within 20 ° C. The polyester composition according to claim 1 or 2.
Polyester A: Polyester having an intrinsic viscosity IV _A of 0.60 to 0.85 deciliter / gram, a crystallization temperature at the time of temperature increase of 140 to 180 ° C. measured by DSC, and a crystallization temperature at the time of temperature decrease of 160 to 200 ° C. .
Polyester B: Polyester having an intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, a crystallization temperature of 140 to 180 ° C. at the time of temperature rise measured by DSC, and a crystallization temperature of 160 to 200 ° C. at the time of temperature fall .   The polyester composition according to claim 1, wherein the content of acetaldehyde is 10 ppm or less and the content of cyclic trimer is 0.70% by weight or less.   The polyester composition according to any one of claims 1 to 4, wherein an increase amount of the cyclic trimer when melted at 290 ° C for 60 minutes is 0.40% by weight or less.   The polyester composition according to any one of claims 1 to 5, wherein a dispersion ratio Mz / Mn of the molecular weight distribution is 3.90 or more.   A polyester molded article obtained by molding the polyester composition according to claim 1.   The polyester molded body is any one selected from a preform for a hollow molded body, a sheet-shaped preform, or a stretched film formed by stretching these preforms in at least one direction or a stretch blow hollow molded body. A polyester molded article characterized by being:   A polyester molded body, wherein the polyester molded body is a coating obtained by melt-extruding a polyester composition on a substrate. The polyester composition according to any one of claims 1 to 6 is kneaded and molded under conditions where the molten resin temperature in the molding machine is 260 to 305 ° C and the melt residence time in the molding machine is 5 to 500 seconds. A method for producing a polyester molded body.

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