JPWO2005100440A1 - POLYESTER RESIN, POLYESTER MOLDED ARTICLE COMPRISING THE SAME, AND METHOD FOR PRODUCING POLYESTER MOLDED PRODUCT - Google Patents

Abstract

The present invention is an aromatic polyester having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, characterized in that the dispersion ratio Mw / Mn of the molecular weight distribution is 3.00 or more, Resin is a polyester resin that produces less molded aldehydes during molding because of improved flow characteristics, and gives molded products with excellent mechanical properties such as pressure resistance when molded. Molded products with low heat distortion and excellent heat-resistant dimensional stability, especially hollow molded products, can be produced efficiently by high-speed molding, and have excellent long-term continuous formability that does not contaminate the mold. A stretched polyester hollow molded article having excellent retainability is provided.

Description

The present invention relates to a polyester resin suitably used as a raw material for a molded body such as a hollow bottle, a sheet-like product, and a stretched film, including a beverage bottle, and a polyester molded body comprising the same, particularly an aldehyde such as acetaldehyde at the time of molding. The production of hollow molds is suppressed, the transparency is excellent and there is little variation in transparency, and the hollow molded body with excellent pressure resistance or pressure resistance and heat-resistant dimensional stability, transparency, slipperiness, and dimensional stability after molding. The present invention relates to an excellent sheet-like product, a polyester molded product such as a stretched film, and a method for producing the polyester molded product.
Background art

Polyesters whose main repeating unit is ethylene terephthalate (hereinafter sometimes abbreviated as PET) are carbonated drinks, juices, mineral water, etc. due to their excellent transparency, mechanical strength, heat resistance, gas barrier properties, etc. It has been adopted as a material for containers and is very popular. In these applications, beverages that have been sterilized at high temperatures are hot-filled in polyester bottles, or sterilized at high temperatures after filling with beverages. Deformation occurs and becomes a problem. As methods for improving the heat resistance of polyester bottles, methods have been proposed in which the bottle cap is heat treated to increase the degree of crystallinity and the stretched bottle is heat-set. In particular, 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 the case of beverages that require hot filling, such as fruit juice beverages, oolong tea, and mineral water, a method of crystallizing by heat treatment of the stopper portion of the preform or molded bottle (Japanese Patent Laid-Open No. 55-79237) Japanese Laid-Open Patent Publication No. 58-110221) is generally used. 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.

Further, in order to improve the heat resistance of the bottle body, a method of heat-treating the stretch blow mold at a high temperature is employed (Japanese Patent Publication No. 59-6216). However, if a large number of bottles are continuously formed using the same mold by such a method, the bottle obtained with a long time operation is whitened, the transparency is lowered, and only a bottle having no commercial value can be obtained. . It has been found that this is due to adhesion of PET due to the PET surface on the mold surface, resulting in mold contamination, which is transferred to the bottle surface. In particular, in recent years, the molding speed has been increased along with the downsizing of bottles, and shortening of the heating time and mold contamination for crystallization of the plug part have become more serious from the viewpoint of productivity. .
In addition, if a lid made of the same material is left after the food is filled in a container obtained by extruding PET into a sheet and vacuum-molded, the container may shrink and the openability of the lid may deteriorate. If left untreated for a long time, it will shrink and the lid will not be able to be formed.

Various proposals have been made to solve such problems. For example, there are a method of adding an inorganic nucleating agent such as kaolin and talc to polyethylene terephthalate and a method of adding an organic nucleating agent such as montanic acid wax salt. There's a problem. In addition, there is a method of adding, to the raw material polyester, a treated polyester obtained by pulverizing a polyester molded body obtained by melt molding from the polyester. However, this method requires an extra step of melt molding and pulverization. There is a risk that contaminants other than polyester will be mixed in the post-process, which is not a preferable method in terms of economy and quality. Moreover, although the method of inserting a heat-resistant resin piece into a cap part is proposed, the productivity of a bottle is bad and there exists a problem also in recyclability. In addition, with the method that has improved the above problems, it is possible to efficiently produce a molded body having excellent transparency and heat-resistant dimensional stability, in particular, a small hollow molded product by high-speed molding, and it is less likely to contaminate the mold. A polyester resin excellent in time-continuous moldability has been proposed, but the heat treatment time of the bottle cap is long.
Further, the polyester contains aldehydes such as acetaldehyde (hereinafter sometimes abbreviated as AA) which is a by-product. When the content of aldehydes in polyester is high, the content of aldehydes in materials such as containers and other packaging that are molded from now on also increases, affecting the flavor and odor of beverages filled in the containers. Effect.

In recent years, polyester containers such as polyethylene terephthalate have come to be used as containers for low flavor beverages such as mineral water and oolong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but it is becoming increasingly important to reduce the acetaldehyde content of the beverage container. In addition, for 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 mainly composed of ethylene terephthalate. 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 heretofore been taken to reduce the acetaldehyde content in the polyester. These measures include, for example, a method of reducing oligomers and aldehydes by subjecting a polyester prepolymer obtained by melt polymerization to solid phase polymerization under reduced pressure or under the flow of an inert gas, A method in which the humidity is adjusted to 2000 ppm or more, followed by crystallization and solid-phase polymerization, a method in which the polyester particles are treated with hot water at 50 to 200 ° C. and then heat-treated under reduced pressure or in an inert gas flow (special (Kaihei 12-120062), and a method of extracting and washing with water or an organic solvent before and after solid-phase polymerization). However, even with a molded body using polyester obtained by these methods, it cannot be said that oligomers and acetaldehyde can be reduced to a problem-free level, and the problem is unsolved, 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. The problem of increasing was occurring.
In addition, a method for producing a heat-resistant polyester container in which a preform formed from two types of molten PET compositions having different intrinsic viscosities of 0.03 or more is treated with a heat-fixing mold under specific temperature conditions (for example, Patent Document 1). Reference) and the resulting heat-resistant polyester container (Japanese Examined Patent Publication No. 62-58973), the intrinsic viscosity of 0.60 to 0.70 dl / g, the specific crystallization temperature at elevated temperature, and the specific crystallization temperature at decreased temperature. A heat-resistant polyester container for stretching and blowing a preform from a mixture of polyester having a polyester having an intrinsic viscosity of 0.77 to 0.90 dl / g, a specific crystallization temperature at elevated temperature, and a specific crystallization temperature at lowered temperature Manufacturing methods (see, for example, Patent Document 2) have been proposed. By these methods, a molded article having stable transparency and a reduced acetaldehyde content is obtained. There are still problems to.
Further, a blend of solid-phase polymerized PET and copolymerized polyethylene terephthalate (for example, see Patent Document 3) has been proposed, and by using this, the acetaldehyde 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.
Japanese Examined Patent Publication No. 62-43851 Japanese Patent Laid-Open No. 10-287799 JP 58-45254 A

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

The present invention solves the problems of the conventional methods described above, suppresses the formation of aldehydes such as acetaldehyde during molding, has excellent transparency and little variation in transparency, and has pressure resistance or heat-resistant dimensional stability. An object of the present invention is to provide a polyester resin capable of efficiently producing a hollow molded body excellent in pressure resistance, particularly a hollow molded body excellent in pressure resistance and heat and pressure resistance by high speed molding, a polyester molded body comprising the same, and a method for producing the same. To do.

The inventors of the present invention have reached the present invention as a result of intensive studies to achieve the above object.
The present invention is as follows.
(1) A polyester resin comprising an aromatic polyester having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, and having a molecular weight distribution dispersion ratio Mw / Mn of 3.00 or more.
(2) A polyester resin containing at least two polyesters having substantially the same composition as a main component, wherein the difference in intrinsic viscosity of the polyester is in the range of 0.05 to 0.30 deciliter / gram, A polyester resin characterized in that the difference in crystallization temperature when the temperature of polyester falls is within 18 ° C.
(3) A polyester resin containing, as main components, the following polyester A and polyester B having ethylene terephthalate as the main repeating unit, and the difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is 0. A polyester resin having a range of from 05 to 0.30, wherein a difference between a crystallization temperature when the temperature of polyester A is lowered and a crystallization temperature when the temperature of polyester B is lowered is within 18 ° C.
Polyester A: intrinsic viscosity IV _A is from 0.60 to 0.75 dl / g, acetaldehyde content of 10ppm or less, the crystallization temperature during heating as measured by DSC 140 to 178 ° C., the crystallization temperature during cooling is Polyester that is 160-190 ° C.
Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.90 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at the time of temperature increase measured by DSC is 140 to 178 ° C., and the crystallization temperature at the time of temperature decrease is Polyester that is 160-190 ° C.
(4) The polyester resin according to any one of (1) to (3), wherein a dispersion ratio Mz / Mn of the molecular weight distribution is 3.60 or more.
(5) The polyester resin according to any one of (1) to (4), wherein the cyclic trimer content is 0.50% by weight or less.
(6) The polyester resin according to any one of (1) to (5), wherein the amount of increase in cyclic ester oligomer when melted at 290 ° C. for 60 minutes is 0.50% by weight or less.

(7) The polyester resin according to any one of (1) to (6), which contains 0.1 to 5000 ppm of fine polyester having the same composition as the polyester.
(8) The polyester resin according to any one of (1) to (7), wherein at least one resin selected from the group consisting of a polyolefin resin and a polyacetal resin is blended in an amount of 0.1 ppb to 50000 ppm. A polyester resin composition.
(9) The polyester resin according to any one of (1) to (8) is kneaded and melted at a melt resin temperature in the molding machine of 260 to 295 ° C. and a melt residence time in the molding machine of 10 to 500 seconds. A method for producing a polyester unstretched molded article, characterized by molding.
(10) A method for producing a stretched polyester molded body, wherein the unstretched molded polyester obtained by the production method of (9) is stretched in at least one direction.

(11) A polyester molded article having a molecular weight distribution dispersion ratio Mw / Mn of 3.00 or more.
(12) A polyester molded product having a molecular weight distribution dispersion ratio Mz / Mn of 3.30 or more.

  The present invention is a polyester resin that provides a molded body with a small amount of aldehydes generated during molding because of improved flow characteristics, and excellent mechanical properties such as pressure resistance when molded. Molded products with little distortion at the time and excellent heat-resistant dimensional stability, especially hollow molded products can be efficiently produced by high-speed molding, and excellent in long-term continuous formability with little mold fouling, A stretched polyester hollow molded article having excellent flavor retention is provided.

Hereinafter, embodiments of the polyester resin of the present invention, a polyester molded body comprising the same, and a method for producing the polyester molded body will be specifically described.
The polyester resin of the present invention is an aromatic polyester having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, and is a polyester resin having a molecular weight distribution dispersion ratio Mw / Mn of 3.00 or more, By increasing the molecular weight distribution, the melt viscosity of the polymer can be reduced, and molding can be performed at lower molding temperatures. As a result, aldehydes such as acetaldehyde can be reduced, and molding with low aldehyde content. You can get a body. In addition, it is advantageous to obtain a bottle with further improved strength, and by using the polyester resin of the present invention, a thin bottle can be easily formed without any problem in terms of strength of the bottle even if the body thickness is reduced.
In addition, because the molding temperature can be lowered for the same reason, it is possible to suppress the formation of cyclic ester oligomers during melt molding, and in particular, small hollow molded products can be efficiently produced by high-speed molding, and therefore productivity is increased. Can provide a polyester resin having a high long-time continuous moldability, which is high and does not contaminate the mold. Moreover, the sheet-like thing excellent in the dimensional stability after shaping | molding can also be given.

The dispersion ratio Mw / Mn of the preferred molecular weight distribution of the aromatic polyester is 3.00 or more, more preferably 3.05 or more, most preferably 3.10 or more, and the dispersion ratio Mw / Mn of the molecular weight distribution is less than 3.00. In order to maintain transparency, it is necessary to increase the melting temperature at the time of molding, and aldehydes such as acetaldehyde in the molded product cannot be reduced. Moreover, it exists in the tendency for the intensity | strength of a bottle to fall.
Here, the dispersion ratios Mw / Mn and Mz / Mn of the molecular weight distribution are calculated from the number average molecular weight (Mn), the weight average molecular weight (Mw) and the Z average molecular weight fraction (Mz) determined by the GPC method. It is a value calculated by Mz / Mn. Details have been described in the section of measurement method (16) below.
As a method for setting the dispersion ratio Mw / Mn of the molecular weight distribution of the aromatic polyester resin to 3.00 or more, a method of blending two or more polymers having substantially the same composition with different number average molecular weights, conditions at the time of polymerization (eg, In the case of a continuous polymerization apparatus, methods such as increasing the residence time or adjusting the number of polymerization tanks) are preferred, and a method of blending two or more polymers having different molecular weight distributions is preferred. The blend may be a molten mixture or a dry blend.

Further, when the polyester resin of the present invention is a polyester resin containing as a main component at least two kinds of polyesters having substantially the same composition, the difference in intrinsic viscosity of the polyester is 0.05 to 0.30 deciliter / gram. The difference in the crystallization temperature when the polyester is cooled is within 18 ° C. The difference in intrinsic viscosity of the polyester is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, and particularly preferably 0.10 to 0.20 deciliter / gram. . When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the content of aldehydes such as acetaldehyde in the obtained molded product cannot be reduced, and the flavor retention cannot be improved. Further, when the above-mentioned intrinsic viscosity difference exceeds 0.30 deciliter / gram, a thickness unevenness, a whitened flow pattern, or the like is generated on the obtained molded product, which causes a problem.
Here, when the polyester resin of the present invention comprises 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.

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 that have been subjected to contact treatment with water under conditions where 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 with water at a high temperature, a method of melt treatment with an extruder, and the like. However, since the hydrolysis method 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 impacts 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 according to the present invention does not include polyester that has been hydrolyzed by a method such as heat treatment under pressure with water or the like, and polyester that has undergone melt treatment to reduce IV.
Further, the difference in the crystallization temperature when the polyester is cooled is preferably within 16 ° C, more preferably within 14 ° C, and particularly preferably within 12 ° C. When the difference in the crystallization temperature when the temperature is lowered exceeds 18 ° C., the transparency of the obtained molded product is very poor.

Further, in the polyester resin of the present invention, the blending ratio of polyester A and polyester B is 95/5 to 5/95, preferably 92/8 to 8/92, more preferably 90/10 to 10/90 in weight ratio. If it is out of this range, the object of the present invention is not achieved, which is not desirable.
The polyester resin of the present invention is a mixture of at least two kinds of polyesters selected from the above-mentioned polyester A and polyester B, respectively, and the compositions of polyester A and polyester B are preferably substantially the same. Here, “substantially the same” means that the acid component and the glycol component in each composition are preferably 95 mol% or more, more preferably 97 mol% or more, particularly 98 mol% or more. It is preferable.

The difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, particularly preferably 0. 10 to 0.20 deciliter / gram. When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the content of aldehydes such as acetaldehyde in the obtained molded product cannot be reduced, and the flavor retention cannot be improved. Further, when the above-mentioned intrinsic viscosity difference exceeds 0.30 deciliter / gram, a thickness unevenness, a whitened flow pattern, or the like is generated on the obtained molded product, which causes a problem.
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 16 ° C, more preferably within 14 ° C, and particularly preferably within 12 ° C. When the difference in the crystallization temperature when the temperature is lowered exceeds 18 ° C., the transparency of the obtained molded product is very poor. In addition, the intrinsic viscosity of polyester affects the crystallization temperature at the time of temperature decrease, and the higher the viscosity, the lower the crystallization temperature at the time of temperature decrease. Therefore, the practical difference in the crystallization temperature at the time of temperature decrease is 2 ° C. or more.

The intrinsic viscosity IV _A of polyester A is preferably 0.62 to 0.74 deciliter / gram, more preferably 0.65 to 0.73 deciliter / gram, and the acetaldehyde content is preferably 8 ppm or less, more preferably 5 ppm or less, The crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C, more preferably 150 to 175 ° C, and the crystallization temperature at the time of temperature drop is preferably 162 to 185 ° C, more preferably 165 to 180 ° C. Or worse the transparency of the obtained molded body when the intrinsic viscosity IV _A is less than 0.60 dl / g of polyester A, the mechanical strength of the molded body has a problem decreases. On the other hand, if it exceeds 0.75 deciliter / gram, the effect of reducing aldehydes such as acetaldehyde is reduced. On the other hand, when the acetaldehyde content exceeds 10 ppm, the flavor retention of the resulting molded product is deteriorated, which is problematic. On the other hand, in the economically profitable method, the limit is 1 ppm or less. Further, when the crystallization temperature of polyester A at the time of temperature rise is less than 140 ° C., the transparency of the molded article is deteriorated, and when it exceeds 178 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. When the crystallization temperature of the polyester A when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization speed of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.86 deciliter / gram, more preferably 0.75 to 0.83 deciliter / gram, and the acetaldehyde content is preferably 8 ppm or less, more preferably 5 ppm or less, The crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C, more preferably 150 to 175 ° C, and the crystallization temperature at the time of temperature drop is preferably 162 to 185 ° C, more preferably 165 to 180 ° C. The intrinsic viscosity of the polyester B IV _B If there is less than 0.73 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.90 deciliter / gram, the heat generation during molding becomes intense and the effect of reducing aldehydes such as acetaldehyde is reduced. On the other hand, when the acetaldehyde content exceeds 10 ppm, the flavor retention of the resulting molded product is deteriorated, which is problematic. On the other hand, in the economically profitable method, the limit is 1 ppm or less. Moreover, when the crystallization temperature at the time of temperature rising of polyester B is less than 140 degreeC, the transparency of a molded object worsens, and when it exceeds 178 degreeC, the crystallization speed improvement effect of a plug part worsens and is a problem. When the crystallization temperature of the polyester B when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated, and when it exceeds 190 ° C., the transparency of the molded article is deteriorated.

  The polyester of the present invention is a thermoplastic polyester mainly obtained from an aromatic dicarboxylic acid component and a glycol component, preferably a polyester containing aromatic dicarboxylic acid units of 70 mol% or more of the acid component, more preferably A polyester in which the aromatic dicarboxylic acid unit contains 85 mol% or more of the acid component, and particularly preferably a polyester in which the aromatic dicarboxylic acid unit contains 95 mol% or more of the acid component.

Examples of the aromatic dicarboxylic acid component constituting the polyester of the present invention include terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid and other aromatic dicarboxylic acids and their functions. And the like.
Examples of the glycol component constituting the polyester of the present invention include aliphatic glycols such as ethylene glycol, 1,3-trimethylene glycol and tetramethylene glycol, and alicyclic glycols such as cyclohexanedimethanol.
Examples of the dicarboxylic acid used as a copolymerization component when the polyester of the present invention is a copolymer include isophthalic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and 4,4′-diphenyl ether. Dicarboxylic acids, aromatic dicarboxylic acids such as 4,4'-diphenylketone dicarboxylic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid Examples thereof include aliphatic dicarboxylic acids such as acid, glutaric acid and dimer acid and functional derivatives thereof, and alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid and functional derivatives thereof.

The glycol as a copolymerization component used when the polyester of the present invention is a copolymer includes diethylene glycol, 1,3-trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, Aliphatic glycols such as decamethylene glycol, 2-ethyl-2-butyl-1,3-propanediol, neopentyl glycol, dimer glycol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexane Alicyclic glycols such as dimethylol, 1,4-cyclohexanedimethylol, 2,5-norbornane dimethylol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-β-hydroxyeth) Aromatic glycols such as xylphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfonic acid, and alkylene oxide adducts of bisphenol A, polyalkylene glycols such as polyethylene glycol and polybutylene glycol Etc.
Furthermore, examples of the polyfunctional compound as a copolymer component used when the polyester of the present invention is a copolymer include trimellitic acid and pyromellitic acid as an acid component, and glycerin as a glycol component. And pentaerythritol. The amount of copolymerization component used should be such that the polyester remains substantially linear. Monofunctional compounds such as benzoic acid and naphthoic acid may be copolymerized.

A preferred example of the polyester of the present invention is a polyester whose main structural unit is composed of ethylene terephthalate, more preferably 70 mol% or more of ethylene terephthalate units, and isophthalic acid, 1,4-cyclohexanedimethanol as a copolymerization component. And particularly preferably a polyester containing 95 mol% or more of ethylene terephthalate units.
Examples of these polyesters include polyethylene terephthalate (hereinafter abbreviated as PET), poly (ethylene terephthalate-ethylene isophthalate) copolymer, poly (ethylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly ( Examples thereof include an ethylene terephthalate-dioxyethylene terephthalate) copolymer, a poly (ethylene terephthalate-1,3-propylene terephthalate) copolymer, and a poly (ethylene terephthalate-ethylene cyclohexylene dicarboxylate) copolymer.
Further, as another preferred example of the polyester of the present invention, the main structural unit is a polyester composed of 1,3-propylene terephthalate, and more preferably a polyester containing 70 mol% or more of 1,3-propylene terephthalate units. Particularly preferred are polyesters containing 95 mol% or more of 1,3-propylene terephthalate units.
Examples of these polyesters include polypropylene terephthalate (PTT), poly (1,3-propylene terephthalate-1,3-propylene isophthalate) copolymer, poly (1,3-propylene terephthalate-1,4-cyclohexanedimethylene). Terephthalate) copolymer and the like.
Further, other preferable examples of the polyester of the present invention are polyesters in which the main structural unit is composed of butylene terephthalate, more preferably a copolyester containing 70 mol% or more of butylene terephthalate units, particularly preferably A polyester containing 95 mol% or more of butylene terephthalate units.
Examples of these polyesters include polybutylene terephthalate (PBT), poly (butylene terephthalate-butylene isophthalate) copolymer, poly (butylene terephthalate-1,4-cyclohexanedimethylene terephthalate) copolymer, poly (butylene terephthalate- 1,3-propylene terephthalate) copolymer, poly (butylene terephthalate-butylene cyclohexylene dicarboxylate) copolymer, and the like.
Further, another preferred example of the polyester of the present invention is a thermoplastic polyester whose main structural unit is composed of ethylene-2,6-naphthalate, and more preferably 70 mol% or more of ethylene-2,6-naphthalate units. The thermoplastic polyester is particularly preferably a thermoplastic polyester containing 90 mol% or more of ethylene-2,6-naphthalate units.
Examples of these thermoplastic polyesters include polyethylene-2,6-naphthalate (PEN), poly (ethylene-2,6-naphthalate-ethylene terephthalate) copolymer, poly (ethylene-2,6-naphthalate-ethylene isophthalate). ) Copolymer, poly (ethylene-2,6-naphthalate-dioxyethylene-2,6-naphthalate) copolymer, and the like.
Another preferred example of the polyester of the present invention is a polyester in which the main structural unit is composed of 1,4-cyclohexanedimethylene terephthalate, and more preferably 70 mol% or more of 1,4-cyclohexanedimethylene terephthalate units. The copolyester containing is particularly preferably a polyester containing 90 mol% or more of 1,4-cyclohexanedimethylene terephthalate units.
Examples of these thermoplastic polyesters include poly-1,4-cyclohexanedimethylene terephthalate (PCT), poly (1,4-cyclohexanedimethylene terephthalate-ethylene terephthalate) copolymer, and the like.

The polyester of the present invention can basically be produced by a conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. These may be composed of batch reactors or may be composed of continuous reactors. 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 of the present invention will be described using polyethylene terephthalate (PET) as an example, but the present invention is not limited thereto. That is, a direct esterification method in which terephthalic acid, ethylene glycol, and if necessary, other copolymerization components are directly reacted and esterified while distilling off water, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst Or transesterification by reacting dimethyl terephthalate with ethylene glycol and other copolymerization components if necessary, and transesterifying while distilling off methyl alcohol, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst Manufactured by. 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 1.5 mol, preferably 1.03 to 1.4 mol of ethylene glycol is added to 1 mol of terephthalic acid or an ester derivative thereof. The contained slurry is prepared and continuously supplied to the esterification reaction step.
In the esterification reaction, water or alcohol produced by the reaction is removed from the system by a rectification column under the condition that 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 1.6 mol, preferably 1.2 to 1.5 mol of ethylene glycol was contained with respect to 1 mol of dimethyl terephthalate. The solution is prepared and continuously fed to the transesterification step.
The transesterification reaction is carried out while removing methanol generated by the reaction outside the system using a rectification column under the condition that ethylene glycol is distilled back using an apparatus in which 1 to 2 transesterification reactors are connected in series. To do. The temperature of the first stage transesterification is 180 to 250 ° C, preferably 200 to 240 ° C. The temperature of the transesterification reaction in the final stage is usually 230 to 270 ° C., preferably 240 to 265 ° C., and as the transesterification catalyst, fatty acid salts such as Zn, Cd, Mg, Mn, Co, Ca, Ba, carbonates Alternatively, 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 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.
As the Ge compound, amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution in which crystalline germanium dioxide is heated and dissolved in water, or a solution in which ethylene glycol is added and heat-treated are used. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water, or a solution in which ethylene glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is preferably 10 to 150 ppm, more preferably 13 to 100 ppm, still more preferably 15 to 70 ppm as the residual amount of Ge in the polyester.
Examples of Ti compounds include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate, and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl succinate, titanyl succinate, titanium trimellitic acid, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, titanium with hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid Complex compound, a complex oxide of titanium and silicon or zirconium, a reaction product of titanium alkoxide and the phosphorus compound. The Ti compound is added so that the remaining amount of Ti in the produced polymer is in the range of 0.1 to 50 ppm.
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 preferably in the range of 50 to 250 ppm.
Examples of 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 their partial hydrolysates, aluminum oxide Umm, and the like. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the remaining amount of Al in the produced polymer is in the range of 5 to 200 ppm.

In the production of the polyester according to the present invention, an alkali metal compound or an alkaline earth metal compound may be used in combination as necessary. The alkali metal or alkaline earth metal is preferably at least one selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, and Ba, and the use of an alkali metal or a compound thereof is preferable. More preferred. When using an alkali metal or a compound thereof, use of Li, Na, K is particularly preferable. Examples of the alkali metal and alkaline earth metal compounds include saturated aliphatic carboxylates such as formic acid, acetic acid, propionic acid, butyric acid, and succinic acid, and unsaturated aliphatic carboxylates such as acrylic acid and methacrylic acid. , Aromatic carboxylates such as benzoic acid, halogen-containing carboxylates such as trichloroacetic acid, hydroxycarboxylates such as lactic acid, citric acid and salicylic acid, carbonic acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, hydrogen carbonate, phosphorus Inorganic acid salts such as acid hydrogen, hydrogen sulfide, sulfurous acid, thiosulfuric acid, hydrochloric acid, hydrobromic acid, chloric acid and bromic acid, and organic sulfonates such as 1-propanesulfonic acid, 1-pentanesulfonic acid and naphthalenesulfonic acid , Organic sulfates such as lauryl sulfate, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butyl Alkoxides such as alkoxy, chelate compounds and the like acetylacetonate, hydrides, oxides, and hydroxides and the like.
The alkali metal compound or alkaline earth metal compound is added to the reaction system as a powder, an aqueous solution, an ethylene glycol solution, or the like. The alkali metal compound or alkaline earth metal compound is added so that the residual amount of these elements in the produced polymer is in the range of 1 to 50 ppm.

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

Also, as stabilizers, phosphoric acid, phosphoric acid esters such as polyphosphoric acid and trimethyl phosphate, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, phosphine compounds It is preferable to use at least one phosphorus compound selected from the group consisting of: Specific examples include phosphoric acid, phosphoric acid trimethyl ester, phosphoric acid triethyl ester, phosphoric acid tributyl ester, phosphoric acid triphenyl ester, phosphoric acid monomethyl ester, phosphoric acid dimethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, Phosphoric acid, phosphorous acid trimethyl ester, phosphorous acid triethyl ester, phosphorous acid tributyl ester, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid dimethylester, phenylphosphonic acid diethylester, phenylphosphonic acid Diphenyl ester and the like. These stabilizers can be added during the esterification reaction step from a slurry preparation tank of terephthalic acid and ethylene glycol. The P compound is added so that the residual amount of P in the produced polymer is preferably in the range of 5 to 100 ppm.
When an Al compound is used as the polycondensation catalyst, it is preferably used in combination with a phosphorus compound, and is preferably used as a solution or slurry in which an aluminum compound and a phosphorus compound are previously mixed in a solvent. In the case of an Al compound, a more preferable phosphorus compound is at least one selected from the group consisting of phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds. It is a phosphorus compound. By using these phosphorus compounds, an effect of improving the catalytic activity is seen, and an effect of improving physical properties such as thermal stability of the polyester is seen. Among these, use of a phosphonic acid compound is preferable because of its great effect of improving physical properties and improving catalytic activity. Among the above-described phosphorus compounds, the use of a compound having an aromatic ring structure is preferable because the physical property improving effect and the catalytic activity improving effect are great.

The melt polycondensation polyester obtained as described above is, for example, a method in which the melt polyester is extruded into water from the die pores after completion of the melt polycondensation and cut in water, or after the melt polycondensation is finished in the air from the die pores. After being extruded into strands, the chips are formed into columns, spheres, squares or plates by a method of forming chips while cooling with cooling water.
Moreover, as the cooling water at the time of chip formation of the melt polycondensed polyester, it is preferable to use cooling water satisfying at least one of the following (1) to (4), and more preferably (1) to (4 It is most preferable to use water that satisfies all of the above.
Na ≦ 1.0 (ppm) (1)
Mg ≦ 1.0 (ppm) (2)
Si ≦ 2.0 (ppm) (3)
Ca ≦ 1.0 (ppm) (4)
The sodium content (Na) in the cooling water is preferably Na ≦ 0.5 ppm, more preferably Na ≦ 0.1 ppm. The magnesium content (Mg) in the cooling water is preferably Mg ≦ 0.5 ppm, more preferably Mg ≦ 0.1 ppm. Further, the content (Si) of silicon in the cooling water is preferably Si ≦ 0.5 ppm, more preferably Si ≦ 0.3 ppm. Furthermore, the calcium content (Ca) in the cooling water is preferably Ca ≦ 0.5 ppm, and more preferably Ca ≦ 0.1 ppm.
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.

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 that the chip temperature is about 70 ° C. or lower, preferably 60 ° C. or lower, more preferably 50 ° C. or lower, within about 30 minutes, preferably within 20 minutes, more preferably within 10 minutes after completion of solid phase polymerization.

When the polyester of the present invention is a polyester whose main repeating unit is ethylene-2,6-naphthalate (hereinafter sometimes abbreviated as PEN), the intrinsic viscosity of at least two kinds of polyesters is 0. It is selected from polyesters in the range of 40 to 0.80 deciliter / gram, preferably 0.42 to 0.75 deciliter / gram, more preferably 0.45 to 0.70 deciliter / gram. When the IV is less than 0.40 deciliter / gram, the mechanical properties of the obtained molded article are poor. In addition, when it exceeds 0.80 deciliter / gram, it becomes necessary to increase the resin temperature at the time of melting by a molding machine or the like, and this is accompanied by thermal decomposition, increasing the number of aldehydes such as acetaldehyde, and the molded product becomes yellow. Problems such as coloring occur.
Furthermore, when the polyester of the present invention is PEN, it contains the following polyester C and polyester D as main components, and there is a difference between the crystallization temperature when the polyester C is cooled and the crystallization temperature when the polyester D is cooled. The polyester resin is preferably within 18 ° C.
Polyester C: Polyester having an intrinsic viscosity IV _A of 0.40 to 0.70 deciliter / gram, a crystallization temperature of 180 to 235 ° C. during temperature rise measured by DSC, and a crystallization temperature of 160 to 210 ° C. during temperature fall .
Polyester D: Polyester having intrinsic viscosity IV _B of 0.50 to 0.80 deciliter / gram, crystallization temperature measured by DSC at 180 to 235 ° C., and crystallization temperature at 160 to 210 ° C. .
When the polyester of the present invention is a polyester whose main structural unit is 1,3-propylene terephthalate, the intrinsic viscosity of at least two kinds of polyesters is 0.50 to 1.00 deciliter / gram, Preferably, polyesters in the range of 0.55 to 0.90 deciliters / gram, more preferably 0.60 to 0.85 deciliters / gram are selected within the scope of the present invention. When the intrinsic viscosity is less than 0.50 deciliter / gram, the mechanical properties of the obtained molded article are deteriorated, which is a problem. The upper limit of the intrinsic viscosity is 1.00 deciliter / gram. If the upper limit is exceeded, the resin temperature at the time of molding becomes high, the thermal decomposition becomes severe, the molecular weight decreases drastically, and the generation of aldehydes is intense. In addition, problems such as yellowing occur.

When the polyester resin of the present invention contains at least two kinds of polyesters as the main components as described above, the type and amount of the polycondensation catalyst, melt polycondensation and solid-state polymerization conditions, etc. are appropriately controlled. Can be manufactured by. 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 ratio of the terminal carboxyl group to the total number of terminal groups of at least one polyester constituting the polyester resin of the present invention is 5 to 30 equivalent%, preferably 8 to 28 equivalent%, more preferably 9 to 26 equivalent%, particularly preferably. It is preferable that it is 10-25 equivalent%. When trying to obtain a polyester having a terminal carboxyl group ratio of less than 5 equivalent% with respect to the total number of terminal groups, the solid phase polymerization time during the production of such a polyester becomes extremely long, resulting in a problem of economy. The generation of aldehydes increases, which is a problem. If the ratio of the terminal carboxyl group to the total number of terminal groups exceeds 30 equivalent%, the transesterification reaction between the two types of polyester is promoted to cause rearrangement of the molecular weight distribution. It is estimated that the improvement effect is lost.

The content of dialkylene glycol copolymerized in the polyester of the present invention is 0.5 to 7.0 mol%, preferably 1.0 to 6.0 mol% of the glycol component constituting the polyester. Preferably it is 1.5-5.0 mol%, More preferably, it is 1.5-4.0 mol%. When the amount of dialkylene glycol exceeds 7.0 mol%, the heat stability is deteriorated, the decrease in molecular weight at the time of molding becomes large, and the increase in the content of aldehydes becomes large. Further, in order to produce a polyester having a dialkylene glycol content of less than 0.5 mol%, it is necessary to select non-economic production conditions as transesterification conditions, esterification conditions or polymerization conditions, and the cost is not suitable. . Here, the dialkylene glycol copolymerized in the polyester, for example, in the case of a polyester whose main structural unit is ethylene terephthalate, is a diethylene glycol (hereinafter referred to as “DEG”) by-produced during the production from ethylene glycol, which is glycol. In the case of a polyester having 1,3-propylene terephthalate as a main structural unit, it is produced from 1,3-propylene glycol, which is a glycol, at the time of production. Of di (1,3-propylene glycol) (or bis (3-hydroxypropyl) ether) produced as a by-product, di (1,3-propylene glycol (hereinafter referred to as DPG) copolymerized with the polyester may be used. ).

In particular, the amount of diethylene glycol copolymerized with the polyester whose main repeating unit is composed of ethylene terephthalate is 1.0 to 5.0 mol%, preferably 1.3 to 4.5 mol, of the glycol component constituting the polyester. %, More preferably 1.5 to 4.0 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in the acetaldehyde content and the formaldehyde content becomes large. Moreover, when diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded object worsens.
In addition, since diethylene glycol and triethylene glycol (hereinafter sometimes referred to as “TEG”) are partially by-produced from ethylene glycol during the polymerization reaction, a predetermined amount of DEG and / or TEG and its ester-forming derivative is used. In addition to the case where is used as a polymerization raw material, the content of the DEG component and / or the TEG component can be controlled only by appropriately selecting reaction conditions, additives and the like. 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 and / or TEG. On the other hand, if a small amount of an inorganic acid such as sulfuric acid is added to the polymerization raw material, the production of DEG and / or TEG can be promoted and the content can be increased. If necessary, these additives for controlling the production amount of DEG and / or TEG are usually used in the range of 0.001 to 10% by weight, preferably 0.005 to 1% by weight of the total polymerization raw material. May be.

Further, the content of aldehydes such as acetaldehyde in the polyester resin of the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 10 ppm or less. When the aldehyde content exceeds 50 ppm, the effect of maintaining the flavor of the contents such as a molded article formed from such polyester is deteriorated. Further, these lower limits are preferably 0.1 ppb from the viewpoint of production. Here, the aldehydes are acetaldehyde in the case where the polyester is a polyester having ethylene terephthalate as a main constituent unit or a polyester having ethylene naphthalate as a main constituent unit, and a polyester having 1,3-propylene terephthalate as a main constituent unit. In the case of allyl aldehyde.
In particular, when the polyester resin of the present invention is composed of a polyester having ethylene terephthalate as a main repeating unit, and this is used as a material for a container for low flavor beverages such as mineral water, the polyester resin of the present invention. The acetaldehyde content of is desirably 10 ppm or less, preferably 6 ppm or less, more preferably 5 ppm or less, and most preferably 4 ppm or less. When the content of acetaldehyde exceeds 10 ppm, the odor and taste of the contents of the molded product molded from this polyester resin are adversely affected, resulting in a problem that the commercial value is lost.

Further, the free ethylene glycol content and the free diethylene glycol content of the polyester resin are preferably 30 ppm or less and 10 ppm or less, preferably 20 ppm or less and 7 ppm or less, more preferably 15 ppm or less and 5 ppm or less, respectively. When the free ethylene glycol content exceeds 30 ppm, or when the free diethylene glycol content exceeds 10 ppm, the free polyethylene glycol content of the obtained polyester molded product exceeds 50 ppm, or the free diethylene glycol content exceeds 20 ppm. For this reason, the flavor retention of the stretched hollow molded article is deteriorated, which is a problem. Moreover, the lower limit values of the free ethylene glycol content and the free diethylene glycol content of the polyester resin are 5 ppm and 1 ppm, respectively, from the viewpoint of economy.
The content of the cyclic ester oligomer of the polyester resin of the present invention is 70% or less, preferably 60% or less, more preferably 50%, of the content of the cyclic ester oligomer contained in the polyester melt polycondensation polyester prepolymer. Hereinafter, it is particularly preferably 35% or less. Here, the polyester generally contains cyclic ester oligomers having various degrees of polymerization. The cyclic ester oligomer referred to in the present invention is the cyclic ester oligomer having the highest content among the cyclic ester oligomers contained in the polyester. An ester oligomer means, for example, a cyclic trimer in the case of a polyester having ethylene terephthalate as a main repeating unit. In the case of PET, in which the polyester is a typical polyester having ethylene terephthalate as a main structural unit, the content of the cyclic trimer of the melt polycondensed polyester prepolymer is about 1.0% by weight. The content of the cyclic trimer of the resin is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, and particularly preferably 0.35% by weight or less. 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, the adhesion of the oligomer to the gas exhaust port of the unstretched molded body mold or the heat fixing mold surface after the stretch molding increases rapidly. The transparency of the obtained hollow molded body or the like is extremely deteriorated.
In addition, when the polyester resin of the present invention is a polyester having ethylene terephthalate as a main repeating unit and is used for forming a highly heat-resistant hollow molded body, heat treatment is performed in a heating mold. The content of the monomer is 0.50% by weight or less, preferably 0.40% by weight or less, more preferably 0.35% by weight or less.

The fine content of the polyester resin 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, still more 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 is impossible, and the stretched heat-fixing mold for molding the heat-resistant hollow molded container is heavily 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 resin for the hollow molded body is preferably 0.1 to 500 ppm.
Further, the difference between the melting point of the fine contained in the polyester of the present invention and the melting point of the polyester chip is 15 ° C. or less, preferably 10 ° C. or less, more preferably 5 ° C. or less. When the difference includes fines exceeding 15 ° C., the crystals are not completely melted under the normally used melt molding conditions and remain as crystal nuclei. For this reason, in the case of a hollow molded body, when the hollow molded body plug portion is heated, the crystallization speed becomes faster, so that the crystallization of the plug portion becomes excessive. In addition, the unstretched molded body for hollow molding is whitened, so that normal stretching becomes impossible, thickness unevenness occurs, and the crystallization speed is high, resulting in poor transparency of the hollow molded body and transparency. The fluctuations are also large.
However, when trying to obtain an unstretched molded article or sheet-like material for hollow molding having good transparency and stretchability from a polyester resin containing a fine whose melting point of the fine and the melting point of the chip exceeds 15 ° C. It must be melt molded at a temperature about 40-50 ° C. higher than the melting point of the polyester chip. However, at such a high temperature, the thermal decomposition of the polyester becomes intense, and a large amount of by-products such as acetaldehyde and formaldehyde are generated, which greatly affects the flavor of the contents of the resulting molded body. It becomes. When the polyester resin of the present invention contains at least one resin selected from the group consisting of the following polyolefin resins, polyamide resins, and polyacetal resins, these resins are generally more thermally stable than the polyester of the present invention. In many cases, it is inferior in properties, and in high-temperature molding as described above, it causes thermal decomposition and generates a large amount of by-products, so it has a greater influence on the flavor of the contents of the obtained molded product etc. It will be.
When the polyester resin of the present invention is PET, a fine or film-like material having a melting point exceeding 265 ° C. becomes a problem.
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.

Further, the increase amount of the cyclic trimer when the polyester resin of the present invention is melted at a temperature of 290 ° C. for 60 minutes is 0.5% by weight or less, preferably 0.3% by weight or less, more preferably 0.1% by weight. It is preferable that it is less than weight%. If the amount of cyclic trimer increased when melted at 290 ° C for 60 minutes exceeds 0.50% by weight, the amount of cyclic trimer will increase when the resin is melted and the oligomer will adhere to the surface of the heated mold. Increases rapidly, and the transparency of the obtained hollow molded article or the like is extremely deteriorated.
The polyester resin 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 0.50% by weight or less is obtained by polycondensation of the polyester obtained after melt polycondensation or after solid phase polymerization. It can be produced by deactivating the catalyst.
Examples of the method of deactivating the polycondensation catalyst of the polyester resin include a method of contacting the polyester chip with water, water vapor or water vapor-containing gas after melt polycondensation or after solid phase polymerization.

In order to achieve the above object, a method of contacting the polyester chip with water, water vapor or water vapor-containing gas will be described below.
Examples of the hot water treatment method include a method of immersing in water and a method of applying water on the chip with a shower. 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.
Although the method of performing water treatment industrially is illustrated below, it is not limited to this. The treatment method may be either a continuous method or a batch method, but the continuous method is preferred for industrial use.
A silo-type treatment tank is used when water-treating polyester chips in a batch system. That is, the polyester chip is received in a silo and treated with water in a batch system. Alternatively, polyester chips can be received in a rotating cylindrical treatment tank, and water treatment can be performed while rotating to make contact with water more efficient.
In the case where the polyester chips are water-treated in a continuous manner, the polyester chips can be continuously or intermittently received in the tower-type treatment tank from the upper part and water-treated. This conceptual diagram is shown in FIG.
When the polyester chip is contacted with water vapor or water vapor-containing gas for treatment, 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 used per 1 kg of the granular polyester. The water vapor is supplied in an amount of 0.5 g or more, or is present to bring the granular polyester into contact with water vapor. The contact between the polyester chip and water vapor is usually performed for 10 minutes to 2 days, preferably 20 minutes to 10 hours.
Although the method of performing the contact treatment of granular polyester, water vapor | steam, or water vapor containing gas industrially below is illustrated, it is not limited to this. The processing method may be either a continuous method or a batch method.
When a polyester chip is contact-treated with water vapor in a batch system, a silo type processing apparatus can be used. That is, a polyester chip is received into a silo, and a contact process is performed by supplying steam or a steam-containing gas in a batch manner. Alternatively, the granular polyester is received in a rotating cylindrical contact processing apparatus, and contact processing can be performed while rotating to make contact more efficient.
In the case where the polyester chips are continuously contacted with water vapor, the granular polyester can be continuously received from the upper part in a tower-type processing apparatus, and the water vapor can be continuously supplied in parallel flow or countercurrent to be contacted with water vapor.
As described above, when treated with water or water vapor, the granular polyester is drained with a draining device such as a vibrating sieve or a Simon Carter as necessary, and transferred to the next drying step.

For drying the polyester chip that has been contact-treated with water or water vapor, a commonly used polyester drying treatment can be used. As a continuous drying method, a hopper type ventilation dryer is generally used in which a polyester chip is supplied from the upper part and a drying gas is supplied from the lower part. As a method of reducing the amount of dry gas and drying efficiently, a rotating disk type heating type continuous dryer is used, and heating steam, heating medium, etc. are supplied to the rotating disk and external jacket while a small amount of drying gas is vented. The polyester chips can be indirectly heated and dried.
As a dryer for drying in a batch system, a double cone type rotary dryer is used, and it can be dried under vacuum or under a vacuum with a small amount of drying gas aerated. Alternatively, drying may be performed while ventilating a dry gas under atmospheric pressure.
As the dry gas, atmospheric air may be used, but dry nitrogen and dehumidified air are preferable from the viewpoint of preventing molecular weight reduction due to hydrolysis or thermal oxidative decomposition of polyester.
By subjecting the polyester resin to water or steam treatment as described above, it is possible to suppress an increase in oligomers after the polyester resin is heated and melted to a temperature of 290 ° C.
Further, by deactivating the catalyst, it is possible to suppress the transesterification reaction at the time of melting such as molding, and the effect of preventing the dispersion ratio Mw / Mn of the molded body from becoming 3.0 or less at the time of melting is also expected.

When a polyester having a wide molecular weight distribution or a greatly different molecular weight, that is, a polyester having a molecular weight distribution dispersion ratio Mw / Mn of 3.0 or more is injection-molded and melt-mixed, the components having a low molecular weight cause the fluidity of the mixed melt. It is presumed that the generation of aldehydes such as acetaldehyde can be suppressed because of the effect of improving and suppressing the increase in the actual temperature of the melt. When the catalyst is deactivated, the transesterification reaction between the mixed polyesters is suppressed, so that the molecular weight distribution hardly undergoes readjustment during the melt residence in the molding machine, and the molecular weight distribution dispersion ratio Mw / Mn is 3 It is estimated that the generation of aldehydes such as acetaldehyde is further suppressed than in the case of non-inactivated products because the flow rate improvement effect of low molecular weight components remains high in the molding machine. Is done.
However, when only a single polyester resin having the same intrinsic viscosity as that of the polyester resin after mixing and a dispersion ratio Mw / Mn of molecular weight distribution of 3.0 or less is injection-molded, the fluidity is improved by the low molecular weight polyester as described above. Since the effect does not occur, the actual temperature at the time of melting is higher than in the case of the above mixture, or the generation of aldehydes such as acetaldehyde is increased.
Moreover, the generation of aldehydes such as acetaldehyde tends to be accelerated by the polymerization catalyst, and the catalyst is preferably deactivated in order to enhance the effect of the present invention.

In addition, as a deactivation method of a polymerization catalyst, it can carry out also by adding a phosphorus compound.
Examples of the phosphorus compound include phosphoric acid compounds, phosphonic acid compounds, phosphinic acid compounds, phosphorous acid compounds, phosphonous acid compounds, and phosphinic acid compounds.
Specific examples of phosphoric acid compounds include, for example, phosphoric acid, dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diamyl phosphate, dihexyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, triamyl phosphate Examples thereof include phosphate, trihexyl phosphate, ester of phosphoric acid and alkylene glycol, and the like.
Specific examples of phosphonic acid compounds include, for example, methylphosphonic acid, dimethyl methylphosphonate, diphenyl methylphosphonate, phenylphosphonic acid, dimethyl phenylphosphonate, diphenyl phenylphosphonate, dimethyl phosphophosphonate, diethyl benzylphosphonate, triethylphosphono Examples include acetate, tributylphosphonoacetate, tri (hydroxyethyl) phosphonoacetate, tri (hydroxypropyl) phosphonoacetate, tri (hydroxybutyl) phosphonoacetate and the like.
Specific examples of phosphinic acid compounds include, for example, diphenylphosphinic acid, methyl diphenylphosphinate, phenyl diphenylphosphinate, phenylphosphinic acid, methyl phenylphosphinate, phenyl phenylphosphinate, 2-carboxyethyl-methylphosphinic acid, 2 -Carboxyethyl-ethylphosphinic acid, 2-carboxyethyl-propylphosphinic acid, 2-carboxyethyl-phenylphosphinic acid, 2-carboxyethyl-m-toluylphosphinic acid, 2-carboxyethyl-p-toluylphosphinic acid, 2- Carboxyethyl-xylylphosphinic acid, 2-carboxyethyl-benzylphosphinic acid, 2-carboxyethyl-m-ethylbenzylphosphinic acid, 2-carboxymethyl-methylphosphinic acid, 2 Carboxymethyl-ethylphosphinic acid, 2-carboxyethyl-propylphosphinic acid, 2-carboxymethyl-phenylphosphinic acid, 2-carboxymethyl-m-toluylphosphinic acid, 2-carboxymethyl-p-toluylphosphinic acid, 2-carboxy Methyl-xylylphosphinic acid, 2-carboxymethyl-benzylphosphinic acid, 2-carboxymethyl-m-ethylbenzylphosphinic acid, and cyclic anhydrides thereof, or methyl ester, ethyl ester, propyl ester, butyl ester thereof , Ethylene glycol ester, propion glycol ester, ester with butanediol, and the like.
Specific examples of phosphorous compounds include phosphorous acid and dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, diamyl phosphite, dihexyl phosphite, trimethyl phosphite, triethyl phosphite. , Triphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylene diphosphite, phosphorous acid and alkylene Examples include esters with glycols.
Specific examples of the phosphonous acid compound include methylphosphonous acid, dimethyl methylphosphonite, diphenyl methylphosphonite, phenylphosphonous acid, phenyldimethylphosphonous acid, and phenyl phenylphosphonite. .
Examples of the method of adding the phosphorus compound include a method of adding at the time of polycondensation, a method of immersing the chip 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 the case of a method using a phosphorus compound in the form of a chip as a method for deactivating the polycondensation catalyst of the polyester resin, a method for determining the deactivation treatment effect is a method for determining the molded product after molding Is preferably used.
In addition, by deactivating the catalyst, a transesterification reaction of the polyester occurs at the time of molding, but this transesterification reaction can be suppressed and the conditions at the time of molding can be made wider.

Further, the difference in the crystallization temperature when the polyester constituting the polyester resin of the present invention is raised is within 10 ° C., preferably within 8 ° C., more preferably within 7 ° C., and particularly preferably within 5 ° C. 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 resin of the present invention is composed of 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 value at the lowest temperature increase. It represents the difference in the values of polyesters having a crystallization temperature.
When the polyester resin of the present invention contains at least two kinds of polyesters as the main components as described above, the type and amount of the polycondensation catalyst, melt polycondensation and solid-state polymerization conditions, etc. are appropriately controlled. Can be manufactured by. 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 of 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 50 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. .
The ratio of the average weight (W) of the polyester constituting the polyester resin of the present invention is 0.80 to 1.20, preferably 0.85 to 1.15, more preferably 0.90 to 1.10, More preferably, it is 0.95 to 1.05, and most preferably 0.97 to 1.03. On the other hand, if the ratio of the average weight (W) is less than 0.80, aldehydes are produced at the time of molding, and a special nozzle is used to produce a chip, resulting in high equipment costs. On the other hand, if it exceeds 1.20, it becomes difficult to melt at the time of molding, which makes it difficult to form at low temperature. In particular, when used for a heat-resistant hollow stretch molded article, if the ratio is outside the range of 0.95 to 1.05, the effect of reducing aldehydes such as acetaldehyde and improving the transparency deteriorates. This is not preferable because unevenness in the blended amount of the polyester is likely to occur, resulting in transparency and thickness unevenness of the polyester unstretched molded body and stretched molded body. Here, when the polyester resin of the present invention comprises two or more kinds of polyesters, the difference in the average weight (W) represents the difference between the value of the largest average weight polyester and the value of the smallest average weight polyester. .

Further, the difference in crystallinity between the polyester chips constituting the polyester resin 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 the stretched hollow molded body is improved. And the effect of reducing the content of acetaldehyde is lost, and the amount of blending of the polyester is liable to occur, which causes the transparency of the polyester unstretched molded body and the stretched hollow molded body and fluctuation of the acetaldehyde content. Absent. Here, when the polyester resin of the present invention is composed of two or more kinds of polyesters, the difference in crystallinity is the difference in crystallinity between the maximum polyester and the minimum polyester with respect to crystallinity. . Here, the crystallinity of the chip is calculated from the density of the chip obtained by the following method.
When the polyester resin 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, the above polyester A and the above polyester B are dry blended with a tumbler, V-type blender, Henschel mixer, static mixer, etc., and the dry blended mixture is 1 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 in a chip form at a predetermined ratio by the appropriate method, dried, and then subjected to molding.

The polyester resin 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 a trap for aldehyde compounds.
Examples of the polyamide to be blended as the aldehyde compound capture 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 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.
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.
Further, 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 terephthalic acid, polyester amide produced from 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 process or extrusion with the polyester resin or cannot be quantitatively extruded. On the other hand, when the temperature exceeds 120 ° C., the polyester unstretched molded body is not stretched uniformly, and thickness spots are generated, which is not preferable.

The shape of the polyamide or polyesteramide chip blended in the polyester resin of the present invention may be any of a cylinder shape, a square shape, a spherical shape or a flat plate shape. 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 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, for example, used 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 resin of the present invention. Can do.

The aldehyde compound trapping material can be blended by adding a predetermined amount of aldehyde compound trapping material at any reaction stage from the production of the 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.
Moreover, it can also obtain by the method of mixing a polyester resin and an aldehyde compound capture | acquisition material by a conventionally well-known method, or the method of mixing an aldehyde compound capture | acquisition material in the mixture of 2 or more types of polyester. For example, polyamide chips and two kinds of polyester chips with different IVs are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture is 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 resin 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 resin 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. 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, so that normal stretching is impossible. Further, in the case of a sheet-like material, if it exceeds 50000 ppm, the transparency becomes very poor, the stretchability is also impaired, and normal stretching is impossible, and only a stretched film with large thickness spots and poor transparency can be obtained. .
As polyolefin resin mix | blended with the polyester resin of this invention, polyethylene-type resin, polypropylene-type resin, or alpha-olefin-type resin is mentioned. These resins may be crystalline or amorphous.

Examples of the polyethylene resin blended in the polyester resin of the present invention include ethylene homopolymer, ethylene, propylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1, and hexene. -1, octene-1, decene-1, etc., other α-olefins having about 2-20 carbon atoms, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, unsaturated Examples thereof include copolymers with vinyl compounds such as epoxy compounds. Specifically, for example, ultra-low / low / medium / high-density polyethylene (branched or linear) ethylene homopolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene- 4-methylpentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer Examples thereof include ethylene resins such as coalescence and ethylene-ethyl acrylate copolymer.
Moreover, as a polypropylene resin mix | blended with the polyester resin of this invention, the homopolymer of propylene, propylene, ethylene, butene-1, 3-methylbutene-1, pentene-1, 4-methylpentene-1, Other α-olefins having about 2 to 20 carbon atoms such as hexene-1, octene-1, decene-1, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, etc. Examples thereof include copolymers with vinyl compounds, and copolymers with dienes such as hexadiene, octadiene, decadiene, dicyclopentadiene, and the like. Specific examples include propylene-based resins such as propylene homopolymer (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymer, propylene-ethylene-butene-1 copolymer.
Moreover, as the α-olefin resin blended in the polyester resin of the present invention, homopolymers of α-olefins having about 2 to 8 carbon atoms such as 4-methylpentene-1, such α-olefins, ethylene , Copolymers with other α-olefins having about 2 to 20 carbon atoms such as propylene, butene-1,3-methylbutene-1, pentene-1, hexene-1, octene-1, and decene-1. It is done. Specifically, for example, butene-1 homopolymers, 4-methylpentene-1 homopolymers, butene-1-ethylene copolymers, butene-1-propylene copolymers, etc. - methylpentene-1 and _C 2 _{-C 18} copolymer of α- olefins, and the like.

Moreover, as a polyacetal resin mix | blended with the polyester resin of this invention, a polyacetal homopolymer and a copolymer are mentioned, for example. The polyacetal homopolymer, the measurement of density measured by a measuring method of ASTM-D792 is ^{1.40~1.42g / cm 3, ASTMD-1238} , 190 ℃, melt flow ratio, measured under a load 2160 g (MFR ) Is preferably in the range of 0.5 to 50 g / 10 min.
Moreover, as a polyacetal copolymer, the density measured by the measuring method of ASTM-D792 is 1.38 to 1.43 g / cm ³ , the melt flow ratio is measured at 190 ° C. and the load is 2160 g by the measuring method of ASTM D-1238. A polyacetal copolymer having a (MFR) in the range of 0.4 to 50 g / 10 min is preferred. Examples of these copolymer components include ethylene oxide and cyclic ethers.
When the polyolefin resin or the like is blended with the polyester resin of the present invention, the resin such as the polyolefin resin is directly added to the polyester resin or the polyester constituting the polyester resin so that the content is in the above range, and melt-kneaded. In addition to a conventional method such as a method of adding or melting and kneading as a master batch, the resin may be produced at the production stage of the polyester, for example, during melt polycondensation, immediately after melt polycondensation, immediately after precrystallization, In the phase polymerization, immediately after the solid phase polymerization, etc., or in the process from the end of the production stage to the molding stage, it is added directly as a granular material, or the polyester chip By a method such as bringing the resin material into contact with the resin member under flow conditions, or a method of melt-kneading after the contact treatment, etc. It is also possible.

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

The polyester unstretched molded product of the present invention can be formed into a film shape, a sheet shape, a hollow molded body shape, or the like by a melt molding method using a generally used extrusion molding machine, an injection molding machine, or the like. It can be obtained in the form of a preform obtained by compression molding the molten mass obtained in this way. Moreover, the polyester unstretched molded product of the present invention can be formed into a polyester stretched molded product by using any stretching method among uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.
Moreover, it is possible to improve mechanical strength by extending | stretching the sheet-like material which consists of a polyester resin of this invention at least to a uniaxial direction. The stretched film made of the polyester resin of the present invention is a stretched film obtained by injection molding or extrusion molding, and any stretching of uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching that are usually used for PET stretching. Molded using the method. Further, it can be formed into a cup shape or a tray shape by pressure forming or vacuum forming.

When the polyester unstretched molded product of the present invention is to be obtained from the polyester resin of the present invention, a transesterification reaction occurs during melt-kneading. Therefore, it is necessary to adjust the melt kneading conditions such as temperature, residence time, shear rate, screw configuration and the like so that the dispersion ratio Mz / Mn of the molecular weight distribution of the polyester unstretched molded product does not fall below 3.30. Specifically, the temperature, residence time, and shear rate should not be increased more than necessary within the range that can be uniformly kneaded, and the screw configuration will ensure plug flow, so do not insert more mixing screws or reverse screws. In addition, it is possible to shorten the melt residence time as much as possible.
The polyester resin is generally stored in an air atmosphere from the time the polymer is polymerized until it is molded, and absorbs moisture during this period. The moisture content absorbed is about 300 to 4000 ppm depending on the storage period. When the polyester resin of the present invention contains at least two or more kinds of polyester as a main component, the difference in moisture content of each polyester before melt molding is 100 ppm or less, preferably 80 ppm or less, more preferably 50 ppm or less, and particularly preferably 30 ppm. Hereinafter, it is most preferably 10 ppm or less. The moisture content of a polyester having a lower intrinsic viscosity (hereinafter sometimes referred to as low IV-polyester) is subtracted from the moisture content of a polyester having a higher intrinsic viscosity (hereinafter sometimes referred to as high IV-polyester). When the difference exceeds 100 ppm, the high IV-polyester in the molding machine is further hydrolyzed to lower the intrinsic viscosity. As a result, the IV difference between the two polyesters becomes smaller than before molding, and the fluidity improving effect as described above. Transparency cannot be exhibited, and the content of aldehydes such as acetaldehyde is also increased. Further, when the difference obtained by subtracting the moisture content of the high IV-polyester from the moisture content of the low IV-polyester exceeds 100 ppm, the low IV-polyester lowers the intrinsic viscosity by hydrolysis in the molding machine. The IV difference becomes larger. In particular, in the case of a polyester resin having an intrinsic viscosity difference of around 0.30 deciliter / gram before molding, the intrinsic viscosity difference is further increased, so that the obtained molded product has thickness spots, whitened flow patterns, and the like. As a result, the transparency becomes worse and becomes a problem. Here, when the polyester resin of the present invention is composed of two or more kinds of polyesters, the difference in moisture content is a difference in moisture content between the maximum polyester and the minimum polyester with respect to the moisture content.
As a condition for molding the polyester unstretched molded article of the present invention, the temperature of the molten resin is 10 to 35 ° C. higher than the melting point of the resin, preferably by heating a barrel or hot runner of an injection molding machine, preferably It is important to set the temperature so that the temperature is higher by 12 to 33 ° C, more preferably by 15 to 30 ° C. Here, the molten resin temperature refers to a temperature at which the resin injected from the tip of a nozzle of an injection molding machine or the like is immediately measured with, for example, a thermocouple thermometer. Here, the melting point is a value determined by a DSC measurement method.

The molding of the polyester molded body of the present invention will be described more specifically with PET as a representative example. Since the polyester resin absorbs moisture, 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, and then the film is formed using a commonly used melt molding method. A molded body to be a sheet, a container, or other packaging material can be molded.
As conditions relating to the production of unstretched molded articles of PET, the molten resin temperature is 260 to 295 ° C., preferably 262 to 290 ° C., more preferably 265 to 285 ° C. by heating a barrel or hot runner of an injection molding machine, etc. Most preferably, it is important to set the temperature in the range of 265 to 280 ° C.
In addition, the melt residence time in the molding machine can be set by arbitrarily selecting the shape of the extruder screw, the L / D, and the extrusion amount in the case of extrusion molding, and 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 10 to 500 seconds, preferably 20 to 200 seconds, more preferably 30 to 150 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 295 ° C. and setting the melt residence time in the range of 10 to 500 seconds, at least two kinds of ethylene terephthalate are mainly used as the main repeating unit. From a polyester resin containing as a main component a low aldehyde content such as acetaldehyde, excellent flavor retention, excellent transparency, and transparent spots (for example, a whitened flow pattern or It is possible to obtain an unstretched molded body for a hollow molded body that is free from the occurrence of a partial whitened product or a bowl-shaped product and has no problem in the shape of the plug portion 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, and the obtained unstretched molded product becomes extremely poor in transparency, and the thickness of the sheet-like material varies. Becomes larger. Moreover, when the temperature exceeds 295 ° C., the thermal decomposition becomes severe and the content of aldehyde such as acetaldehyde becomes high, which is a problem. When the melt residence time is less than 10 seconds, the transparency of the unstretched molded article becomes poor due to insufficient melting, and when it exceeds 500 seconds, the transparency of the unstretched molded article becomes very good, but acetaldehyde or the like The aldehyde content becomes high, the molding cycle becomes long, and the productivity of the unstretched molded product decreases.
Below, the concrete manufacturing method about the various uses in the case of PET is demonstrated easily.
In producing a stretched film, the stretching temperature is usually 80 to 130 ° C. Stretching may be uniaxial or biaxial, but biaxial stretching is preferred from the viewpoint of film physical properties. In the case of uniaxial stretching, the stretching ratio is usually 1.1 to 10 times, preferably 1.5 to 8 times. In the case of biaxial stretching, the longitudinal and transverse directions are usually 1.1 to 8 times, respectively. Preferably, it may be performed in a range of 1.5 to 5 times. The vertical / horizontal magnification is usually 0.5 to 2, preferably 0.7 to 1.3. The obtained stretched film can be further heat-set to improve heat resistance and mechanical strength. The heat setting is usually performed under tension at 120 to 240 ° C., preferably 150 to 230 ° C., usually for several seconds to several hours, preferably several tens of seconds to several minutes. The stretched film has a thickness of about 5 to 100 microns.

Further, in producing the stretched hollow molded body, the polyester unstretched molded body of the present invention is stretch blow molded, and an apparatus conventionally used in blow molding of PET can be used. Specifically, for example, an unstretched molded body is once formed by injection molding or extrusion molding, and the plug portion and the bottom portion are processed as they are, and then re-heated, and then, such as hot parison method or cold parison method. An axial stretch blow molding method is applied. The polyester unstretched molded body is stretched after being unstretched by heating or temperature adjustment to about 90 to 110 ° C, preferably about 95 to 105 ° C. The stretching temperature is usually 70 to 120 ° C, preferably 90 to 110 ° C.
In the case of a pressure- and heat-resistant and pressure-resistant polyester stretched hollow molded body, the stretch ratio is 5 to 15 times, preferably 7 to 12 times in terms of area stretch ratio. In order to impart heat resistance, the film is heat-set after being stretch-blown and then held at a mold temperature of 100 to 180 ° C., preferably 110 to 150 ° C. for 1 second or more, preferably 3 seconds or more.
Moreover, in the case of a highly heat-resistant polyester stretched hollow molded article, the stretch ratio is 5 to 10 times, preferably 6 to 8 times in terms of area stretch ratio. The obtained polyester stretched hollow molded body crystallizes the plug portion, particularly in the case of a beverage that requires hot filling such as a fruit juice carbonated beverage. In order to impart heat resistance to the plug part, the plug part of the polyester unstretched molded product obtained by injection molding or extrusion molding is crystallized in a far infrared or near infrared heater installation oven, or after bottle molding The plug part is crystallized with the heater. In order to impart heat resistance to the body part, after stretching and blowing, it is held at a mold temperature of 110 to 230 ° C., preferably 120 to 210 ° C., for 1 to 30 seconds, preferably 1 to 20 seconds, Heat fixed.
In addition, after extending | stretching blow-molding as mentioned above, cooling gas, such as nitrogen and air, is blown into the inside of a molded object, and it cools.
In addition, a stretched hollow molded body can be obtained by a so-called compression molding method in which a preform obtained by compression molding a molten mass cut after melt extrusion of the polyester resin of the present invention is stretched.

In the polyester resin of the present invention, known ultraviolet absorbers, antioxidants, infrared absorbers, oxygen scavengers, lubricants added from the outside, lubricants precipitated internally during the reaction, mold release agents, cores as necessary Various additives such as agents, stabilizers, antistatic agents, bluing agents, dyes and pigments, and a polyamide resin from metaxylylenediamine and adipic acid may be added to improve oxygen permeability.
In addition, when the stretched polyester body obtained from the unstretched polyester body of the present invention is a stretched film, calcium carbonate, magnesium carbonate, in order to improve handling properties such as slipperiness, rollability and blocking resistance, Inorganic particles such as barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, terephthalate, divinylbenzene, styrene Inactive particles such as cross-linked polymer particles such as acrylic acid, methacrylic acid, acrylic acid, or vinyl monomers of acrylic acid or methacrylic acid may be used.

The dispersion ratio Mw / Mn of the molecular weight distribution of the polyester unstretched or polyester stretch-molded product obtained as described above using the polyester resin of the present invention is 3.00 or more, preferably 3.05 or more. More preferably, it is 3.10 or more. If the dispersion ratio Mw / Mn of the molecular weight distribution is less than 3.00, the transparency of the molded product is poor, and aldehydes such as acetaldehyde in the molded product cannot be reduced. Further, only a stretched polyester article having a lower mechanical strength can be obtained.
The dispersion ratio Mz / Mn of the molecular weight distribution of the polyester unstretched or polyester stretch-molded body of the present invention is 3.30 or more, preferably 3.33 or more, more preferably 3.35 or more, and particularly preferably 3. 37 or more. If the dispersion ratio Mz / Mn of the molecular weight distribution is less than 3.30, the transparency of the molded product is poor as described above, and aldehydes such as acetaldehyde in the molded product cannot be reduced, which is not preferable. Further, only a stretched polyester article having a lower mechanical strength can be obtained.

In addition, the content of aldehydes in the polyester unstretched or polyester stretch-molded body of the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 20 ppm or less.
Further, when the polyester stretched molded product of the present invention is made of a polyester resin having ethylene terephthalate as a main repeating unit, and this is used as a material for a container for low flavor beverages such as mineral water, The acetaldehyde content of the stretched polyester molded product is 15 ppm or less, preferably 12 ppm or less, more preferably 10 ppm or less, and most preferably 7 ppm or less.
Further, the formaldehyde content of the stretched hollow polyester body of the present invention is 5 ppm or less, preferably 3 ppm or less, more preferably 2 ppm or less, and most preferably 1 ppm or less.
The free ethylene glycol content of the stretched hollow polyester body of the present invention is 50 ppm or less, preferably 40 ppm or less, more preferably 30 ppm or less, most preferably 20 ppm or less, and the free diethylene glycol content is 20 ppm or less, preferably 15 ppm or less, more preferably 13 ppm or less, and most preferably 10 ppm or less.

When the polyester unstretched molded product of the present invention is made of a polyester resin having ethylene terephthalate as a main repeating unit, the crystallization temperature (Tc1) at the time of temperature rise is 140 to 175 ° C. The crystallization temperature (Tc2) of is preferably 160 to 190 ° C. When Tc1 is less than 140 ° C., whitening occurs during preheating before molding, resulting in poor stretchability and poor transparency. When Tc1 exceeds 175 ° C., the crystallization process of the plug part of the hollow molded body for heat-resistant applications becomes insufficient, and the plug part is deformed when hot filling a hot beverage, causing leakage after capping. It becomes.

The polyester unstretched molded body or stretched hollow molded body of the present invention preferably has an increase in cyclic trimer of 0.40% by weight or less when melted at a temperature of 290 ° C. for 60 minutes, For this purpose, the polyester used can be produced by deactivating the polyester polycondensation catalyst obtained after melt polycondensation or after solid phase polymerization as described above. The increase amount of the cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is preferably 0.3% by weight or less, more preferably 0.1% by weight or less. If the increase exceeds 0.4% by weight, the cyclic trimer, linear monomer, and linear oligomer increase when the resin is melted during molding, and the adhesion of the oligomer to the vent hole of the molding die increases rapidly and continues. Production becomes difficult, and flavor retention of the obtained stretched polyester hollow molded article is deteriorated.

EXAMPLES 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.
The composition and characteristics of the polyester are measured after the chips are frozen and ground and mixed thoroughly.
(1) Intrinsic viscosity of polyester (IV)
It calculated | required from the solution viscosity at 30 degreeC in a 1,1,2,2-tetrachloroethane / phenol (2: 3 weight ratio) mixed solvent. The IV of the polyester resin was a weighted average value calculated from the IV of the constituent polyester.
(2) Polyethylene glycol content of polyester (hereinafter referred to as [DEG content])
Decomposition with methanol, the amount of DEG was quantified by gas chromatography, and expressed as a ratio (mol%) to the total glycol components.
(3) Polyester cyclic trimer content (hereinafter referred to as “CT content”)
300 mg of the frozen and ground sample is dissolved in 3 ml of a hexafluoroisopropanol / chloroform mixed solution (volume ratio = 2/3), and further diluted with 30 ml of chloroform. To this is added 15 ml of methanol to precipitate the polymer, followed by filtration. The filtrate was evaporated to dryness, made up to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography.
(4) Increasing amount of cyclic trimer at the time of melting polyester (△ CT amount)
The polyester resin is frozen and pulverized, and then 3 g of the dried polyester sample is put into a glass test tube and immersed in an oil bath at 290 ° C. for 60 minutes in a nitrogen atmosphere and melted. The amount of increase in cyclic trimer at the time of melting is determined by the following equation.
The cyclic trimer content before melting was the weighted average value of the cyclic trimer content of the polyester constituting the polyester resin.
Increase in cyclic trimer during melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)
In addition, when calculating | requiring the cyclic | annular trimer increase amount at the time of the fusion | melting of a molded object, the thin piece about about 1-3 mm in size is cut out from the mouth of the molded object shape | molded by the postscript (16), and it is set as a sample.
(5) Acetaldehyde content of polyester (hereinafter referred to as “AA content”) and AA increase before and after molding (hereinafter referred to as “ΔAA amount”)
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 preform, a sample was taken from the mouth. The amount of ΔAA is the AA amount of the molded body sample−the AA amount of the chip before molding. The amount.
(6) 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 )
(7) Ratio of average weight (W) and average weight of polyester chip The ratio of the average weight (W) and average weight of the polyester chip is about the maximum 100 polyester chips dried after removing fines with ion-exchanged water. The weight was measured, and the average value was defined as the average weight (W).
In this case, the selection of 100 chips was performed by excluding abnormally sized chips. That is, 100 chips are selected at random and the average weight (W) is calculated. Then, chips with a weight less than 0.5 W and chips with a weight exceeding 2 W are excluded, and the number of excluded chips is selected again at random. Then, 100 average values were recalculated. This was performed until all 100 chips were within 0.5 W to 2 W.
Moreover, the ratio of the average weight of polyester A and polyester B was calculated | required by calculating with the following formula from the average weight of each polyester chip | tip calculated | required in this way.
Average weight ratio = average weight of polyester A / average weight of polyester B

(8) About 5 to 10 g of sodium content and calcium content of polyester are 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.
(9) About 5 to 10 g of silicon content sample of polyester is put into a platinum crucible and incinerated at about 550 ° C. Then, sodium carbonate is added and dissolved by heating, and dissolved in 1N hydrochloric acid. This solution was measured with an inductively coupled plasma optical emission spectrometer manufactured by Shimadzu Corporation.
(10) Measurement of Fine Content About 0.5 kg of resin, a sieve (A) with a nominal size of 5.6 mm according to JIS-Z8801, and a sieve with a nominal size of 1.7 mm (diameter) 20 cm) (B) was placed on a sieve combined in two stages, and sieved at 1800 rpm for 1 minute with a swing type sieve shaker SNF-7 manufactured by Terraoka. This operation was repeated and a total of 20 kg of resin was sieved. However, when the fine content is small, the amount of the sample is appropriately changed.
The fine sieved under the sieve (B) is washed with a 0.1% aqueous cationic surfactant solution, then washed with ion-exchanged water, and filtered through a G1 glass filter manufactured by Iwaki Glass Co., Ltd. It was. These were dried together with a glass filter in a dryer at 100 ° C. for 2 hours, then cooled and weighed. Again, the same operations of washing and drying with ion-exchanged water were repeated to confirm that a constant weight was reached, 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.
(11) 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 (10), fines collected from 20 kg of polyester were dried under reduced pressure at 25 ° C. for 3 days, and then DSC measurement was performed at a heating rate of 20 ° C./min using 4 mg of sample for one measurement. The melting peak temperature on the highest temperature side of the peak temperature is determined. 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.
(12) Crystallization temperature (Tc1) when the molded body is heated and crystallization temperature (Tc2) when the temperature is lowered
Measured with a differential thermal analyzer (DSC), RDC-220, manufactured by Seiko Electronics Industry Co., Ltd. Using 10 mg of a sample from the center of a 2 mm thick plate of the molded plate of (15) below. The temperature was raised at a rate of temperature rise of 20 ° C./minute and held at 290 ° C. for 3 minutes, then the temperature was lowered from 290 ° C. to 240 ° C. at 10 ° C./minute, and further from 240 ° C. to 130 ° C. at 7 ° C./minute. The temperature dropped. The peak temperature of the crystallization peak observed at the time of temperature rise is defined as the crystallization temperature (Tc1) at the time of temperature increase, and the peak temperature of the crystallization peak observed at the time of temperature decrease is defined as the crystallization temperature (Tc2).
(13) Haze (degree of haze) and haze spots A sample was cut from the molded product (thickness 5 mm) of (15) below, and measured with a Nippon Denshoku Co., Ltd. haze meter, model NDH2000. Moreover, the haze of the shaping | molding board (wall thickness 5mm) 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 Further, 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 (16) below.

(14) Number average molecular weight Mn, weight average molecular weight Mw, Z average molecular weight Mz, molecular weight distribution dispersion ratio Mw / Mn, and molecular weight distribution dispersion ratio Mz / Mn
The number average molecular weight Mn, the weight average molecular weight Mw, and the Z average molecular weight Mz were determined by the GPC method.
However, the number average molecular weight Mn and the weight average molecular weight Mw in the case of obtaining the molecular weight distribution dispersion ratio Mw / Mn are obtained in the integration range 1, and the number average molecular weight Mn and Z in the case of obtaining the molecular weight distribution dispersion ratio Mz / Mn. The average molecular weight Mz was determined in the integration range 2.
(Preparation of sample) 1 mg of a sample was 0.2 ml of chloroform / hexafluoroisopropanol = 3/2.
After dissolving in (vol%), the sample solution was prepared by diluting with 3.8 ml of chloroform.
(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) The peak start was set to 450,000 with standard polystyrene.
The peak end was 250 with standard polystyrene.
(Integration range 2) Peak start with standard polystyrene, peak rise point,
The peak end was 700 with standard polystyrene.
The dispersion ratio Mw / Mn and the dispersion ratio Mz / Mn of the molecular weight distribution were obtained from the following.
Dispersion ratio of molecular weight distribution = Mw / Mn
Dispersion ratio of molecular weight distribution = Mz / Mn
In the case of an unstretched molded body and a stretched hollow molded body, a sample was taken from the mouth.
(15) Molding of stepped molded plate
The polyester dried under reduced pressure at 140 ° C. for about 16 hours using a vacuum dryer has a gate part (G) as shown in FIGS. 1 and 2 by an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 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) The stepped molding plate was injection molded.
Polyester previously dried under reduced pressure using a vacuum dryer DP61 manufactured by Yamato Scientific was used, and a dry inert gas (nitrogen gas) purge was performed in the molding material hopper to prevent moisture absorption during molding. The plasticizing conditions with 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 the injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2 g. In this case, the holding pressure is 0.5 MPa 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.
The mold is always controlled by introducing cooling water having a water temperature of 10 ° C., but the mold surface temperature at the time of molding stability is around 22 ° C.
The molding temperature refers to the set temperature of the barrel including the nozzle.
The stepped molding plates used for measurement of various polyester molding plates Tc1 and Tc2 used in Examples and Comparative Examples are molding plates molded at a 290 ° C. molding temperature.
Moreover, in the measurement of the molded resin haze (%) and molded plate haze spot (%) of the polyester resin in Examples and Comparative Examples, in Examples 1 to 3 and Comparative Example 1, a molded plate having a molding temperature of 290 ° C. was used. In other examples and comparative examples, a molded plate having a molding temperature of 280 ° C. was used.
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 crystallization temperature (Tc1) during temperature rise and a crystallization temperature (Tc2) during temperature drop, and a 5 mm-thick plate (part D in FIG. 1) has haze (degree %) Used for measurement.
(16) Molding of hollow molded body 1) Molding of preform A molding material hopper is used to prevent moisture absorption of the chip during molding using a polyester chip that has been dried in advance using a vacuum dryer DP63 model manufactured by Yamato Scientific Co., Ltd. The inside was purged with a dry inert gas (nitrogen gas).
The plasticizing conditions of the 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 below 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. or 290 ° 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, and the total cycle time including the molded product take-out time is approximately 42 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 a 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 is taken from the mouth of the bottle, measurement of acetaldehyde content (AA content), cyclic trimer content (CT content), number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz ) And dispersion ratio, free EG content, and free DEG content.

(17) Strength measurement of bottle body part The body part of the bottle formed by the above method is cut into a large size with a cutter and punched with a super dumbbell cutter model SDMK-1000D manufactured by Dumbbell Co., Ltd. (according to JISK-7162-5A). The strength was measured using a tensile tester SS-207D-U (manufactured by Toyo Baldwin Co., Ltd.).
(18) Appearance of Hollow Molded Body Twenty hollow molded bodies from the tenth molding start of (16) were visually observed and evaluated as follows.
◎: Transparent and no appearance problems △: There is a little whitened flow pattern or whitened product in the hollow molded body ×: White hollow flow pattern or whitened product is present (19) Mouth of unstretched molded body for hollow molded body Plug Shape and Size The shape and size of the unstretched molded product mouthpiece crystallized in (16) above 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.
(20) Free glycol content of polyester (hereinafter, free ethylene glycol content is referred to as “free EG content”, and free diethylene glycol content is referred to as “free DEG content”)
About 1.000 g of a sample is precisely weighed and dissolved in 8 mL of a hexafluoroisopropanol / chloroform (2/3) mixed solvent in an Erlenmeyer flask, and then 3 mL of distilled water is added to homogenize the contents. The mixed solvent is distilled off, and the residual aqueous phase is filtered using a glass fiber filter. The filtrate was made up to 10 mL with water and quantified by gas chromatography.
(21) Sodium content, magnesium content, calcium content and silicon content of chip cooling water or treated water are collected and filtered with a 1G1 glass filter manufactured by Iwaki Glass Co., Ltd., and the filtrate is manufactured by Shimadzu Corporation. Measurements were made with an inductively coupled plasma emission spectrometer.

(Polyester 1)
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately and continuously supplied to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr for 1 hour under stirring in the third polymerization reactor. The number average molecular weight of the obtained PET was 13,000, and the intrinsic viscosity (IV) was 0.53.
The resin was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 205 ° C. under a nitrogen atmosphere. After the solid-phase polymerization, the fine particles were removed by continuous treatment in the sieving step and the fine removal step.
The obtained PET had an intrinsic viscosity of 0.70 deciliter / gram, a number average molecular weight of 20000, a dispersion ratio of 2.6, a cyclic trimer content of 0.32% by weight, and a density of 1.400 g / cm ³ (crystal The degree of conversion was 56.3%.
For water treatment of PET 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, Discharge port (3) for the mixture of the polyester-based polyester chip and the treated water, the treated water discharged from the overflow outlet, the treated water discharged from the treating tank, and the drainer discharged from the discharge item at the bottom of the treating tank Pipe (6) in which treated water passed through (4) is sent again to the water treatment tank via a fine powder removing device (5) whose filter medium is a paper 30 μm continuous filter, these fine powder removed treatments A tower-shaped treatment tank having an internal capacity of about 320 liters, equipped with a water inlet (7), an adsorption tower (8) for adsorbing acetaldehyde in treated water after fine powder removal, and a new ion-exchanged water inlet (9) Use .
The water is continuously fed into the water treatment tank controlled at a treatment water temperature of 95 ° C. at a rate of 50 kg / hour from the supply port (1) at the upper part of the treatment tank. A PET chip was continuously extracted from the discharge port (3) at the bottom of the treatment tank together with the treated water at a rate of 50 kg / hour. The obtained PET had an acetaldehyde (AA) content of 3 ppm and a cyclic trimer (CT) content of 0.32% by weight. The properties of the obtained PET are shown in Table 1.

(Polyester 2)
High purity terephthalic acid and ethyl glycol are continuously supplied to the first esterification reactor containing the reactants in advance, and the average residence time is 3 hours at about 250 ° C. and 0.5 kg / cm ² G with stirring. Reaction was performed. In addition, crystalline germanium dioxide was dissolved in water by heating, and a catalyst solution in which ethylene glycol was added and heat-treated thereto and an ethylene glycol solution of phosphoric acid were separately and continuously supplied to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm 2 G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr for 1 hour under stirring in the third polymerization reactor. The number average molecular weight of the obtained PET was 13,000, and the intrinsic viscosity (IV) was 0.53.
The resin was subsequently crystallized at about 155 ° C. under a nitrogen atmosphere, further preheated to about 200 ° C. under a nitrogen atmosphere, and then sent to a continuous solid-phase polymerization reactor for solid phase polymerization at about 205 ° C. under a nitrogen atmosphere. After the solid-phase polymerization, the fine particles were removed by continuous treatment in the sieving step and the fine removal step.
The obtained PET resin has an intrinsic viscosity of 0.85 deciliter / gram, a number average molecular weight of 26000, a dispersion ratio of 2.6, a cyclic trimer content of 0.30% by weight, and a density of 1.400 g / cm ³ ( The degree of crystallinity was 56.3%).
In the water treatment of the PET chip, the same apparatus as in the previous period was used and the treatment was performed under almost the same conditions.
The obtained PET had an acetaldehyde (AA) content of 3 ppm and a cyclic trimer (CT) content of 0.30% by weight. The properties of the obtained PET are shown in Table 1.

(Polyester 3, 4)
Polyesters 3 and 4 were synthesized in the same manner as described above except that the solid phase polymerization time was changed. The results are shown in Table 1.
(Polyester 5)
In the same manner as for polyester 1, melt polycondensation and solid phase polymerization were performed to obtain polyester 5.
In addition, as cooling water at the time of chip formation of the melt polycondensation polymer, the sodium content is 0.1 ppm, the calcium content is about 0.2 ppm, the magnesium content is about 0.04 ppm, and the silicon content is about 0.6 ppm. Ion-exchanged water was used.
The obtained PET has an intrinsic viscosity of 0.70 deciliter / gram, an acetaldehyde (AA) content of 3.4 ppm, a cyclic trimer content of 0.34% by weight, a free ethylene glycol content of 20 ppm, and a free diethylene glycol content. The amount is 8 ppm, the tip shape is elliptical, the tip average weight (W) is 24.7 mg, the tip crystallinity is 56.3%, the sodium content is 0.03 ppm, the calcium content is 0.05 ppm, silicon The content was 0.6 ppm, the fine content was about 50 ppm, and the fine melting point was 250 ° C. The properties of the obtained PET are shown in Table 2.
(Polyester 6, 7)
Polyesters 6 and 7 were obtained by reacting in the same manner as polyester 5 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 2. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 8)
Uses water with a sodium content of about 10.0 ppm, a calcium content of about 12.3 ppm, a magnesium content of about 5.9 ppm, and a silicon content of 12.0 ppm as cooling water when chipping, eliminating the fine removal step Except that, polyester 8 was obtained by melt polycondensation and solid phase polymerization in the same manner as polyester 5.
The properties of the obtained PET are shown in Table 2. The fine content was about 900 ppm, the sodium content was 5.1 ppm, the calcium content was 5.6 ppm, and the silicon content was 6.5 ppm.
(Polyester 9, 10)
Polyesters 9 and 10 were obtained in the same manner as the polyester 5 except that the average chip weight (W) was changed as shown in Table 2 and the solid phase polymerization time was changed.
The properties of the obtained PET are shown in Table 2. Sodium content, calcium content, and silicon content were similar to those of polyester 1.
(Polyester 11)
A prepolymer was obtained by melt polycondensation in the same manner as polyester 5 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 213 ° C. After solid-phase polymerization, fines were removed in the sieving step. The properties of the obtained PET are shown in Table 2. Sodium content, calcium content, and silicon content were similar to those of polyester 5.
(Polyester 12)
Polyester 12 was obtained in the same manner as Polyester 5 except that the melt polycondensation time was extended to IV = 0.61 deciliter / gram and the solid phase polymerization time was shortened.
The properties of the obtained PET are shown in Table 2. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 13, 14)
Polyester 5 except that the water used for cooling into chips was water having a sodium content of about 11.9 ppm, a calcium content of about 10.3 ppm, and a silicon content of 15.0 ppm, and omitting the sieving step and the fine removal step. Alternatively, polyester 13 and 14 were obtained by melt polycondensation and solid phase polymerization in the same manner as polyester 6. Table 3 shows the properties of the obtained PET. The sodium content, calcium content, and silicon content were the same as or higher than those of polyester 8.
(Polyester 15, 16)
As the polycondensation catalyst, the same procedure as for polyester 5 or polyester 6 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol has been heat-treated in advance is used. By reacting, polyesters 15 and 16 were obtained.
Table 3 shows the properties of the obtained PET. Sodium content, calcium content, and silicon content were similar to those of polyester 5.
(Polyester 17, 18)
Polyesters 17 and 18 were obtained by reacting in the same manner as polyester 5 or polyester 6 except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst.
The properties of the obtained PET are shown in Table 2. Sodium content, calcium content, and silicon content were similar to those of polyester 5.
(Polyester 19, 20)
Polyesters 19 and 20 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.
Table 3 shows the properties of the obtained PET. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Polyester 21)
The polyester 5 is continuously fed into the following water treatment tank controlled at a treatment water temperature of 95 ° C. at a rate of 50 kg / hour from the supply port (1) at the upper part of the treatment tank for water treatment. A PET chip was continuously extracted from the discharge port (3) with treated water at a rate of 50 kg / hour. The introduced water collected in front of the ion exchange water inlet (9) of the water treatment apparatus has a particle content 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 having a particle diameter of 1 to 40 μm of recycled water after treatment in the filtration device (5) and the 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 in Example 1.
For water treatment of the polyester chip, 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 Discharge port (3) for the mixture of polyester chip and treated water, treated water discharged from this overflow discharge port, treated water discharged from the treatment tank, and draining device (4 ) Through which the treated water is sent again to the water treatment tank via the fine powder removing device (5) whose filter medium is a paper-made continuous filter, and the introduction of the treated water after removal of the fine powder. A tower-type treatment tank having an internal capacity of about 50 m ³ equipped with a mouth (7), an adsorption tower (8) for adsorbing acetaldehyde in treated water after fine powder removal, and a new ion-exchange water inlet (9) was used. .
The properties of the obtained PET are the same as those of the polyester 5 described in Table 3 except that the cyclic trimer increase amount (ΔCT amount) upon melting is 0.15% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 5.
(Polyester 22)
Polyester 6 was treated with water in the same manner as described above to obtain polyester 22.
The properties of the obtained PET are the same as the properties of polyester 6 described in Table 3 except that the amount of increase in cyclic trimer (ΔCT amount) upon melting is 0.15% by weight. Sodium content, calcium content, and silicon content were similar to those of polyester 5.

(Example 1)
The polyester resin obtained by blending the above synthesized polyester 1 and polyester 2 pellets in a ratio of 7: 3 is injection molded by the method (16) under the conditions of a molten resin temperature of 290 ° C. and a melt residence time of 110 seconds. The preform and stretch-molded bottle obtained in this manner were evaluated. The results are shown in Table 3.
In addition to the following Examples 2 and 3 and Comparative Example 1, the molded plate haze is the value of a 5 mm thick plate (D in FIG. 1) obtained by the method (15) at a molding temperature of 290 ° C.
Also,
(Examples 2 and 3)
The polyester resins of Examples 2 and 3 were evaluated in the same manner as Example 1 with the compositions shown in Table 3. The results are shown in Table 3.
(Comparative Example 1)
The polyester resin of Comparative Example 1 was evaluated in the same manner as in Example 1 with the composition shown in Table 3, but clearly compared with Example 1 having the same number average molecular weight, the polyester resin composition of Comparative Example 1 The ΔAA was high, and the bottle strength was as low as 186 MPa. The results are shown in Table 3.
Example 4
The polyester resin obtained by blending the above polyester 5 and polyester 6 pellets in a ratio of 7: 3 was molded at 290 ° C. by the method (15) and the molten resin temperature was changed to 280 ° C. ( The preform and stretch-molded bottle obtained by the method of 16) were evaluated. The results are shown in Table 3.
There is no problem in the shape and dimensions of the unstretched molded body plug after crystallization, the stretched hollow molded body has an AA content of 8.5 ppm, a cyclic trimer content of 0.38% by weight, and a free ethylene glycol content. Was 25 ppm, the free diethylene glycol content was 10 ppm, and the haze was 1.2%.
(Example 5)
The polyester resin of Example 5 was evaluated in the same manner as in Example 4 with the composition shown in Table 4 using a mixture of water-treated PET. The results are shown in Table 3. All the evaluated characteristics were as good as in Example 4. Further, the amount of increase in cyclic trimer (ΔCT amount) during melting was as low as 0.15% by weight.
(Example 6)
Evaluation was carried out in the same manner as in Example 4 for the polyester resin composition of Example 6 in which 1,70 parts by weight of polyester, 2,30 parts by weight of polyester, and 1, 1 part by weight of polyamide were blended. The results are shown in Table 4.
The stretched hollow molded article had a low AA content of 5.7 ppm, a good haze of 1.5%, and other characteristics were satisfactory.

(Comparative Example 2)
As shown in Table 4, the polyester 3 of Comparative Example 2 was evaluated in the same manner as in Example 4.
Obviously, the AA content and haze value of the stretched hollow molded article were high compared to the Examples, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization were poor. The results are shown in Table 4.
(Comparative Example 3)
As shown in Table 4, the polyester resin of Comparative Example 3 was evaluated.
Obviously, the haze value of the stretched hollow molded body was high, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization were poor as compared with the Examples. The results are shown in Table 4.
(Comparative Example 4)
As shown in Table 4, the polyester resin of Comparative Example 4 was evaluated.
Obviously, the AA content, free ethylene glycol content, free diethylene glycol content and haze value of the stretched hollow molded body are high compared with the examples, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization are It was bad. The results are shown in Table 4.
(Comparative Example 5)
As shown in Table 4, the polyester resin of Comparative Example 5 was evaluated.
Obviously, the AA content and haze value of the stretched hollow molded article were high compared to the Examples, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization were poor. The results are shown in Table 4.
(Comparative Example 6)
As shown in Table 4, the polyester resin of Comparative Example 6 was evaluated.
Obviously, the AA content and haze value of the stretched hollow molded article were high compared to the Examples, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization were poor. The results are shown in Table 4.
(Comparative Example 7)
As shown in Table 4, the polyester resin of Comparative Example 7 was evaluated.
Obviously, the AA content, free ethylene glycol content, free diethylene glycol content haze value of the stretched hollow molded body is high compared to the examples, and the shape and dimensions of the stretched hollow molded body plug portion after crystallization are poor. Met. The results are shown in Table 4.

(Example 7)
The polyester resin of Example 7 was evaluated in the same manner as in Example 4 with the composition shown in Table 5. The results are shown in Table 5. All the evaluated characteristics were as good as in Example 4.
(Example 8)
The polyester resin of Example 8 was evaluated in the same manner as in Example 4 with the composition shown in Table 5. The results are shown in Table 5. All the evaluated characteristics were as good as in Example 4.
Example 9
The polyester resin of Example 9 was evaluated in the same manner as Example 4 with the composition shown in Table 5. The results are shown in Table 5. All the evaluated characteristics were as good as in Example 4.
(Comparative Example 8)
Molding evaluation was performed in the same manner as in Example 4 except that the same polyester resin as in Example 4 was used and the molten resin temperature was changed to 300 ° C. and the melt residence time was changed to 520 seconds. The shape of the plug part of the preform is poor and the dimensions are out of specification, and it is “x”. The appearance of the stretched hollow molded article is “、”, the haze is 1.3%, but the AA content is 32.1 ppm. The free EG content was 64 ppm, the free DEG content was 28 ppm, and the bottle body strength was 180 Mpa.

INDUSTRIAL APPLICABILITY The present invention provides a molded product that has a small amount of aldehydes during molding due to improved flow characteristics, and has excellent mechanical properties such as pressure resistance when formed into a molded product. Provide a polyester resin to give. In addition, since the polyester resin of the present invention has improved flow characteristics, there is little distortion during molding, and a molded article with excellent heat-resistant dimensional stability
In particular, hollow molded products can be produced efficiently by high-speed molding, yet give a molded product with very good pressure resistance and heat-resistant dimensional stability, and excellent long-term continuous formability with little fouling. Polyester resin, a molded body comprising the same, and a method for producing the molded body.

Claims (12)

A polyester resin, which is an aromatic polyester having a repeating unit mainly composed of an aromatic dicarboxylic acid component and a glycol component, and having a molecular weight distribution dispersion ratio Mw / Mn of 3.00 or more. A polyester resin containing as a main component at least two polyesters having substantially the same composition, wherein the difference in intrinsic viscosity of the polyester is in the range of 0.05 to 0.30 deciliter / gram, and the temperature drop of the polyester A polyester resin characterized in that the difference in crystallization temperature at the time is within 18 ° C. A polyester resin containing, as a main component, the following polyester A and polyester B having ethylene terephthalate as a main repeating unit, and the difference between the intrinsic viscosity IV _A of polyester _A and the intrinsic viscosity IV _B of polyester B is 0.05-0. A polyester resin characterized in that 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 18 ° C.
Polyester A: intrinsic viscosity IV _A is from 0.60 to 0.75 dl / g, acetaldehyde content of 10ppm or less, the crystallization temperature during heating as measured by DSC 140 to 178 ° C., the crystallization temperature during cooling is Polyester that is 160-190 ° C.
Polyester B: Intrinsic viscosity IV _B is 0.73 to 0.90 deciliter / gram, acetaldehyde content is 10 ppm or less, crystallization temperature at the time of temperature increase measured by DSC is 140 to 178 ° C., and the crystallization temperature at the time of temperature decrease is Polyester that is 160-190 ° C. The polyester resin according to any one of claims 1 to 3, wherein a dispersion ratio Mz / Mn of the molecular weight distribution is 3.60 or more. The polyester resin according to claim 1, wherein the cyclic trimer content is 0.50% by weight or less. The polyester resin according to any one of claims 1 to 5, wherein an increase amount of the cyclic ester oligomer when melted at a temperature of 290 ° C for 60 minutes is 0.50% by weight or less. The polyester resin according to any one of claims 1 to 6, comprising 0.1 to 5000 ppm of fine polyester having the same composition as the polyester. A polyester resin composition comprising the polyester resin according to claim 1 and at least one resin selected from the group consisting of a polyolefin resin and a polyacetal resin in an amount of 0.1 ppb to 50000 ppm. The polyester resin according to any one of claims 1 to 8 is kneaded and molded under the conditions that the molten resin temperature in the molding machine is 260 to 295 ° C and the melt residence time in the molding machine is 10 to 500 seconds. A method for producing a polyester unstretched molded article. A method for producing a stretched polyester molded body, wherein the unstretched molded polyester body obtained by the production method according to claim 9 is stretched in at least one direction. A polyester molded product having a molecular weight distribution dispersion ratio Mw / Mn of 3.00 or more. A polyester molded product having a molecular weight distribution dispersion ratio Mz / Mn of 3.30 or more.