JP2006096041A - Manufacturing method of polyester preform and polyester oriented formed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for producing effectively a preform for a hollow formed body by a high-speed forming in which acetaldehyde formation is suppressed at forming, superior in a transparency, a pressure proofness or a heat-resistant dimensional stability and a polyester orieted formed body made thereby. <P>SOLUTION: The method comprises one for manufacturing the polyester preform made by forming a polyester composition comprising at least two of mainly ethylene terephthalate as a main repeated unit. The method is characteristic by kneading and forming the polyester composition which has a difference between intrinsic viscosities of at least two kinds of polyesters of 0.05-0.30 dl/g in a melt forming condition where a randomness (R) of a formed body made by forming a mixture for securing a forming condition comprised of a polyethylene terephthalate of 50 pts.wt. and a polyethylene naphthalate of 50 pts.wt. may be ≤0.50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a method for producing a polyester preform using a polyester composition mainly composed of polyethylene terephthalate, in particular, it has a low content of aldehydes such as acetaldehyde, is excellent in flavor retention, has an appropriate crystallization speed, and is transparent. The present invention relates to a method for producing a preform for a hollow molded article that is excellent and has little variation in transparency. Further, the polyester stretch molded article has a low content of aldehydes such as acetaldehyde, excellent transparency, and little variation in transparency. It relates to a manufacturing method.

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

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

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

  For example, such polyester is supplied to a molding machine such as an injection molding machine to form a preform for a hollow molded body, and the preform is inserted into a mold having a predetermined shape and stretched blow molded to cool it. It is made into a hollow molded container for beverages, or it is molded into a heat-resistant or pressure-resistant hollow molded container by heat-treating the preform plug part (crystallization of the plug part) and then stretching blow molding and heat-treating the body part (heat set). It is common.

  However, PET contains acetaldehyde (hereinafter sometimes abbreviated as AA) as a by-product during melt polycondensation. Moreover, PET produced acetaldehyde by thermal decomposition when thermoforming a molded body such as a hollow molded body, and the acetaldehyde content in the material of the obtained molded body was increased, and the hollow molded body was filled. Affects the flavor and odor of beverages.

  In recent years, polyester containers such as polyethylene terephthalate have come to be used as containers for low flavor beverages such as mineral water and oolong tea. In the case of such beverages, these beverages are generally heat-filled or sterilized by heating after filling, but 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 whose main repeating unit is ethylene terephthalate. The method to do has come to be adopted. In this case as well, the contents are filled and sterilized by heating at a high temperature. 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 been taken to reduce the acetaldehyde content in the polyester. As these measures, for example, a method of reducing the AA content by solid-phase polymerization of melt-polycondensed polyester (see, for example, Patent Document 1), AA at the time of molding using a copolyester having a lower melting point A method for reducing the production (for example, see Patent Document 2), a method for adjusting the moisture content of the polyester prepolymer so that the moisture content is 2000 ppm or more, and then performing crystallization and solid-phase polymerization (for example, see Patent Document 3), polyester A method in which particles are treated with hot water at 50 to 200 ° C. and then heat-treated under reduced pressure or in an inert gas flow (for example, see Patent Document 4). Extraction and washing with water or an organic solvent before and after solid-phase polymerization A processing method (for example, see Patent Document 5), a method for reducing the molding temperature as much as possible during thermoforming, and a shear stress during thermoforming as much as possible. Such as how to reduce has been proposed. However, even in a molded body using polyester obtained by these methods, it cannot be said that oligomers and acetaldehyde can be reduced to a problem-free level, and the problem remains unsolved.

  Also, a method for producing a heat-resistant polyester container in which a preform formed from two kinds of PET melt-mixed 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 6). And a heat-resistant polyester container obtained (see, for example, Patent Document 7), having an intrinsic viscosity of 0.60 to 0.70 dl / g, a specific crystallization temperature at the time of temperature increase, and a specific crystallization temperature at the time of temperature decrease Production of a heat resistant polyester container for stretching and blowing a preform from a mixture of polyester and a polyester having an intrinsic viscosity of 0.77 to 0.90 dl / g, a specific crystallization temperature at elevated temperature and a specified crystallization temperature at lowered temperature Methods (see, for example, Patent Document 8) have been proposed. To obtain a molded article having stable transparency and a reduced acetaldehyde content even by these methods. But there is a problem. Further, a blend of solid-phase polymerized PET and copolymerized polyethylene terephthalate (for example, see Patent Document 9) has been proposed, and by using this, the AA content of the hollow molded body can be reduced. Since the copolymer component is present, there is a problem in the heat resistance and pressure resistance of the obtained molded body, which is not satisfactory and a solution is awaited.

  In addition, a method using a polyester composition in which 0.05 parts by weight or more and less than 1 part by weight of a metaxylylene group-containing polyamide resin is added to 100 parts by weight of a polyester resin (see, for example, Patent Document 10) or thermoplastic polyester Polyester containers made of a polyester composition containing a specific polyamide whose terminal amino group concentration is regulated within a certain range have been proposed (for example, see Patent Document 11). Polyester molding obtained by these techniques Even if it is a body, there are problems of insufficient acetaldehyde reduction, crystallization speed fluctuation and cost increase, and a solution is awaited.

  Furthermore, in recent years, thinning of bottles has been attempted, and as a result, attempts have been made to increase the molecular weight in order to increase the strength of the bottle, but by increasing the molecular weight, the melt viscosity during molding increases and the amount of acetaldehyde generated is increased. There was an increasing problem.

JP-A-53-73288 Japanese Patent Laid-Open No. 57-16024 JP-A-2-298512 JP-A-8-120062 Japanese Patent Laid-Open No. 55-13715 Japanese Examined Patent Publication No. 62-43851 Japanese Examined Patent Publication No. 62-58973 Japanese Patent Laid-Open No. 10-287799 JP 58-45254 A Japanese Examined Patent Publication No. 6-6661 Japanese Examined Patent Publication No. 4-71425

  The present invention solves the above-mentioned problems of the prior art, suppresses the formation of acetaldehyde at the time of molding, has excellent transparency, and a method for producing a polyester preform having an appropriate crystallization speed, particularly stable. Manufacturing that efficiently produces preforms for hollow molded articles with dimensional accuracy at the mouth, excellent transparency and little variation in transparency, with excellent flavor retention, pressure resistance, or heat-resistant dimensional stability by high-speed molding It is an object of the present invention to provide a method and a method for producing a stretched polyester molded body comprising the method.

  The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object. That is, the present invention relates to a polyester preform (hereinafter simply referred to as “preliminary product”) formed by molding a polyester composition containing at least two types of polyesters mainly composed of ethylene terephthalate as a main repeating unit. The manufacturing method is a randomness (R) of a molded product obtained by molding a molding condition grasping mixture comprising 50 parts by weight of polyethylene terephthalate and 50 parts by weight of polyethylene naphthalate. The polyester composition having a difference in intrinsic viscosity between at least two of the polyesters of 0.05 to 0.30 deciliters / gram is kneaded and molded under a melt molding condition in which the ratio is 0.50 or less. It is a manufacturing method of a polyester preform. Furthermore, the present invention is characterized in that the polyester composition is kneaded and molded under molding conditions such that the degree of randomness (R) of the molded body is preferably 0.40 or less, more preferably 0.30 or less. It is a manufacturing method of a polyester preform. Polyester molded product with a low degree of aldehyde content such as acetaldehyde and excellent flavor retention and transparency under molding conditions where the degree of randomness (R) is 0.50 or less, or excellent transparency and transparent spots (For example, a whitened flow pattern generated on a molded body or a partially whitened or wrinkled product) is not generated, and there is no problem in the shape of the plug portion after crystallization. Can be obtained. In particular, in the case of a wall-thickened molded article such as a bottle, these effects become significant.

In the case of molding conditions where the degree of randomness (R) exceeds 0.50, the thermal decomposition becomes severe, the content of aldehydes such as acetaldehyde becomes high, and the crystallization rate becomes slow. The lower limit of the randomness (R) is 0.05. Under the conditions below this, the torque load of an injection molding machine or the like is large due to insufficient melting, making molding difficult, and the obtained preform is transparent. The properties are extremely deteriorated, and the variation in thickness is increased.
In addition, randomness (R) is a scale which shows the block property of copolymerization polyester, and is the value calculated | required by the NMR method shown below.

  The difference in intrinsic viscosity of the polyester constituting the polyester composition used in the present invention is preferably 0.06 to 0.27 deciliter / gram, more preferably 0.07 to 0.23 deciliter / gram, and particularly preferably Is from 0.10 to 0.20 deciliter / gram. When the above-mentioned intrinsic viscosity difference is less than 0.05 deciliter / gram, the acetaldehyde content of the obtained molded product cannot be reduced, and the flavor retention cannot be improved. Further, when the above-mentioned intrinsic viscosity difference exceeds 0.30 deciliter / gram, a thickness unevenness, a whitened flow pattern, or the like is generated on the obtained molded product, which causes a problem.

  In the present invention, polyethylene terephthalate and polyethylene naphthalate used for grasping the molding conditions will be described in the following Examples section.

  Here, the polyester preform is an unstretched sheet obtained by melt extrusion molding a polyester, a preform obtained by compression molding a melt mass obtained by melt extrusion molding, or injection molding. It is the preform etc. which are obtained. Further, it is a molded body that is melt-extruded and extruded into a pipe shape (so-called direct blow molded body), and then a cylindrical molded body that is further molded into a container, a cup-shaped molded body that is obtained by injection molding, Also included are molded products that are commercialized as containers by laminating paper and non-woven fabrics.

In the present invention, when there are two kinds of polyester constituting the polyester composition, the composition ratio is 97/3 to 3/97, preferably 95/5 to 5/95, more preferably 90, by weight. / 10 to 10/90.
The compositions of these polyesters 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.

  In the present invention, in the case of extrusion molding, by selecting the shape of the extruder screw, L / D, etc., and arbitrarily setting the extrusion amount, etc., in the case of injection molding, the cycle time and metering of the injection molding machine By appropriately setting the melt residence time by arbitrarily setting the stroke (screwback amount), etc., and by appropriately setting the molten resin temperature by heating the barrel or hot runner of an extruder or injection molding machine, etc. The molding condition obtained by molding a molding condition grasping mixture composed of 50 parts by weight of polyethylene terephthalate and 50 parts by weight of polyethylene naphthalate is ascertained for molding conditions where the randomness (R) of the molded product is 0.50 or less. It is preferable to knead and mold a polyester composition having a difference in intrinsic viscosity of 0.05 to 0.30 deciliter / gram below. Arbitrariness.

  In the method for producing a polyester preform according to the present invention, an increase in the actual temperature in a molding machine or the like can be suppressed because the low molecular weight component in the polyester having a low intrinsic viscosity exhibits the effect of improving the fluidity of the mixed melt. In addition, the obtained preform can suppress the generation of aldehydes such as acetaldehyde, and at the same time improve the transparency. It is considered to be good. Therefore, under conditions where the degree of randomness exceeds 0.50, for example, the transesterification reaction between two polyesters is promoted to cause rearrangement of the molecular weight distribution. It is estimated that the improvement effect is lost.

In this case, the polyester composition includes the following polyester A and polyester B as main components, and the difference between the crystallization temperature when the temperature of polyester A is lowered and the crystallization temperature when the temperature of polyester B is lowered is 20 ° C. It is preferable to use the polyester composition within.
Polyester A: A polyester having an intrinsic viscosity IV _A of 0.60 to 0.80 deciliter / gram, an acetaldehyde content of 10 ppm or less, and a crystallization temperature measured by DSC of 160 to 200 ° C.
Polyester B: Polyester having an intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, an acetaldehyde content of 10 ppm or less, and a crystallization temperature measured by DSC of 160 to 200 ° C.

  The difference between the crystallization temperature when the temperature of the polyester A is lowered and the crystallization temperature when the temperature of the polyester B is lowered is preferably within 18 ° C, more preferably within 15 ° C, and particularly preferably within 10 ° C. When the difference in the crystallization temperature when the temperature is lowered exceeds 20 ° C., the transparency of the obtained molded product is very poor. In addition, the lower limit of the difference in crystallization temperature when the temperature is lowered is 2 ° C. or more, and if it is less than this, the difference in effect is not clear.

The intrinsic viscosity IV _A of polyester A is preferably 0.62 to 0.75 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 reduction is preferably 162 to 190 ° C, more preferably 165 to 180 ° C. If the intrinsic viscosity IV _A of the polyester A is less than 0.60 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.80 deciliter / gram, the effect of reducing acetaldehyde is lowered. 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. When the crystallization temperature at the time of temperature reduction of the polyester A is less than 160 ° C., the crystallization speed is slow when the unstretched portion of the polyester molded product is crystallized, and the productivity of the molded product becomes worse. Moreover, when it exceeds 200 degreeC, the transparency of a polyester molded object worsens and it is a problem.

The intrinsic viscosity IV _B of polyester B is preferably 0.74 to 0.90 deciliter / gram, more preferably 0.75 to 0.85 deciliter / gram, and the acetaldehyde content is preferably 8 ppm or less, more preferably 5 ppm or less. The crystallization temperature at the time of temperature reduction is preferably 162 to 190 ° 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 0.95 deciliter / gram, heat generation during molding becomes intense and the effect of reducing acetaldehyde becomes low. 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. When the crystallization temperature at the time of temperature reduction of the polyester A is less than 160 ° C., the crystallization speed is slow when the unstretched portion of the polyester molded product is crystallized, and the productivity of the molded product becomes worse. Moreover, when it exceeds 200 degreeC, the transparency of a polyester molded object worsens and it is a problem.

  By using the polyester composition in the method for producing a polyester preform according to the present invention, a more stable preform can be molded, and the effect of reducing the acetaldehyde content is great and the flavor retention is further improved. A stretched hollow molded body having excellent transparency and stable dimensional accuracy at the mouth can be obtained.

  In this case, the polyester composition includes the following polyester C and polyester D as main components, and the difference between the chip bulk density of polyester C and the chip bulk density of polyester D is within 0.10 gram / cubic centimeter, In addition, it is preferable to use a polyester composition in which the difference between the crystallization temperature when the temperature of polyester C is lowered and the crystallization temperature when the temperature of polyester D is lowered is within 15 ° C.

Polyester C: Intrinsic viscosity IV _C is 0.60 to 0.80 deciliter / gram, bulk density is 0.80 to 0.97 gram / cubic centimeter, and crystallization temperature when measured by DSC is 140 to 180 ° C. A polyester having a crystallization temperature of 160 to 190 ° C. when the temperature is lowered.
Polyester D: Intrinsic viscosity IV _D is 0.73 to 0.95 deciliter / gram, bulk density is 0.80 to 0.97 gram / cubic centimeter, crystallization temperature is 140 to 180 ° C. at the time of temperature rise measured by DSC, A polyester having a crystallization temperature of 160 to 190 ° C. when the temperature is lowered.
Here, the DSC measurement is performed by the following method on a molded plate (2 mm thickness) injection-molded at 290 ° C. by the following method.

  The difference in bulk density between them is preferably within 0.08 grams / cubic centimeter, more preferably within 0.05 grams / cubic centimeter, and particularly preferably within 0.03 grams / cubic centimeter. When the difference in bulk density exceeds 0.10 g / cubic centimeter, when the molded product is produced from the polyester, the variation of the blending ratio in the time series direction becomes large, so that the intrinsic viscosity and crystallization of the molded product are increased. Variations in properties occur, resulting in a molded product having large thickness spots, stretch spots, and transparent spots, which is a problem. The effect is not clear when the difference in bulk density between the two is within 0.01 gram / cubic centimeter. Further, the difference between the crystallization temperature when the temperature of the polyester C is lowered and the crystallization temperature when the temperature of the polyester D is lowered is preferably within 13 ° C, more preferably within 10 ° C, and particularly preferably within 8 ° C. When the difference in the crystallization temperature at the time of the temperature drop exceeds 15 ° C., the transparency of the obtained molded product becomes very poor, the fluctuation of the crystallization speed during crystallization of the plug portion becomes large, and the dimensional accuracy is poor. It is a problem. Further, the intrinsic viscosity of polyester affects the crystallization temperature at the time of temperature drop, and the higher the viscosity, the lower the crystallization temperature at the time of temperature drop. Therefore, the practical difference in the crystallization temperature at the time of temperature drop is 2 ° C. or more.

The intrinsic viscosity IV _C of the polyester C is preferably 0.62 to 0.78 deciliter / gram, more preferably 0.65 to 0.75 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-185 degreeC, More preferably, it is 165-180 degreeC. If the intrinsic viscosity IV _C of the polyester C is less than 0.60 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.80 deciliter / gram, the effect of reducing acetaldehyde is lowered. Moreover, when the crystallization temperature at the time of raising the temperature of polyester C is less than 140 ° C., the transparency of the molded article is deteriorated, and when it exceeds 180 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated. When the crystallization temperature of the polyester C when the temperature is lowered is less than 160 ° C., the effect of improving the crystallization speed of the plug portion becomes worse, and when it exceeds 190 ° C., the transparency of the molded article is worsened.

The intrinsic viscosity IV _D of polyester D is preferably 0.74 to 0.90 deciliter / gram, more preferably 0.75 to 0.85 deciliter / gram, and the crystallization temperature at the time of temperature rise is preferably 145 to 177 ° C. More preferably, it is 150-175 degreeC, The crystallization temperature at the time of temperature fall becomes like this. Preferably it is 162-185 degreeC, More preferably, it is 165-180 degreeC. If the intrinsic viscosity IV _D of the polyester D is less than 0.73 dl / g is a problem deteriorates the transparency of the resulting molded product. On the other hand, if it exceeds 0.95 deciliter / gram, heat generation during molding becomes intense and the effect of reducing acetaldehyde becomes low. Moreover, when the crystallization temperature at the time of raising the temperature of the polyester D is less than 140 ° C., the transparency of the molded article is deteriorated. When the crystallization temperature at the time of temperature reduction of the polyester D is less than 160 ° C., the effect of improving the crystallization rate of the plug portion is deteriorated.

  In addition, as polyester A or polyester B, or polyester C or polyester D, it is possible to use at least one or more of each polyester that falls within the above-mentioned characteristic range. As polyester B, it is also possible to make a polyester composition in which one kind of polyester is used and mixed so as to have the above-mentioned composition ratio.

In the method for producing a polyester preform of the present invention, the flowability in the melt molding machine is further improved by using a polyester composition having the above-mentioned characteristics, so that molding at a lower temperature is possible, and acetaldehyde-containing It is possible to obtain a preform for a stretched polyester molded body such as a stretched polyester hollow molded body having a smaller amount, superior in flavor retention and transparency, and free from the occurrence of the above-mentioned transparency and excellent in heat resistance. I can do it. In addition, the method for producing a stretched polyester molded body of the present invention can provide a stretched polyester body such as a stretched polyester hollow container excellent in high heat resistance or heat pressure resistance.

In this case, it is preferable to use a polyester composition having an acetaldehyde content of 10 ppm or less.
In this case, it is preferable to use a polyester composition having a cyclic trimer content of 0.70% by weight or less.

In this case, it is desirable that the cyclic trimer increase amount when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less.
Here, the amount of increase in cyclic trimer when melted for 60 minutes at a temperature of 290 ° C. is obtained from a 3 mm thick plate of a stepped molded plate obtained by the molding method described in the “Measurement Method” section below. This is the value obtained for the sample.

  In this case, it is desirable to use a polyester composition blended with 0.1 ppb to 1000 ppm of at least one resin selected from the group consisting of polyolefin resin, polyamide resin, and polyacetal resin.

  In the present invention, the polyester preform obtained by the above production method is stretched in at least one direction, and the preform is biaxially stretched or biaxially stretched blow molded. In addition, if necessary, the stretch-molded body after stretch molding is heat-fixed as necessary, so that it has low acetaldehyde content and excellent flavor retention, and is biaxially stretched with excellent mechanical properties such as transparency and elastic modulus and tensile strength. A stretched molded body excellent in heat fixability can be obtained.

  According to the present invention, there is provided a method for producing a preform having an appropriate crystallization rate, in which the production of acetaldehyde at the time of molding is suppressed, the transparency is excellent, the variation in transparency is small, and the obtained is obtained. By performing biaxial stretching or biaxial stretching blow molding of the preform, or heat setting after that, it has low acetaldehyde content, excellent flavor retention, and excellent mechanical properties such as transparency and elastic modulus and tensile strength. In addition, a biaxially stretched film, a hollow molded body, and a method for producing a stretched molded body having excellent heat fixability can be provided.

Hereinafter, embodiments of the method for producing a polyester preform of the present invention will be specifically described.
That is, the polyester used in the present invention is a linear polyester containing 85 mol% or more of ethylene terephthalate units, preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 97 mol% or more. Polyester.

Examples of the dicarboxylic acid used for copolymerization of the polyester include isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyru 4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, Aromatic dicarboxylic acids such as 1,3-phenylene dioxydiacetic acid and functional derivatives thereof, oxyacids such as p-oxybenzoic acid and oxycaproic acid and functional derivatives thereof, adipic acid, sebacic acid, succinic acid, Examples thereof include aliphatic dicarboxylic acids such as glutaric acid and dimer acid and functional derivatives thereof, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid and cyclohexanedicarboxylic acid, and functional derivatives thereof.
Examples of the glycol used for copolymerization of the polyester include aliphatic glycols such as diethylene glycol, trimethylene glycol, tetramethylene glycol and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, bisphenol A and alkylene oxides of bisphenol A. Examples include aromatic glycols such as adducts.

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

  The polyester used in the present invention can basically be produced by a conventionally known melt polycondensation method or melt polycondensation method-solid phase polymerization method. The melt polycondensation reaction may be performed in one stage or may be performed in multiple stages. These may be comprised from a batch-type reaction apparatus, and may be comprised from the continuous-type reaction apparatus. The melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately. Hereinafter, an example of a preferable continuous production method of the polyester used in 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 is directly reacted with ethylene glycol and, if necessary, other copolymerization components to distill off water and esterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst, or , Produced by a transesterification method in which dimethyl terephthalate, ethylene glycol, and other copolymerization components as required are reacted to distill off methyl alcohol and transesterify, followed by polycondensation under reduced pressure in the presence of a polycondensation catalyst. Is done. Then, when the intrinsic viscosity is increased or the low acetaldehyde content or the low cyclic trimer content is used, such as a heat-resistant container for low flavor beverages or a film for inner surfaces of metal cans for beverages. The resulting melt polycondensed polyester is subsequently subjected to solid state polymerization.

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

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

When terephthalic acid is used as a raw material, the esterification reaction can be carried out without a catalyst by the catalytic action of terephthalic acid as an acid, but may be carried out in the presence of a polycondensation catalyst.
Also, tertiary amines such as triethylamine, tri-n-butylamine, benzyldimethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydroxide, and lithium carbonate When a small amount of a basic compound such as sodium carbonate, potassium carbonate or sodium acetate is added, the proportion of dioxyethylene terephthalate component units in the main chain of polyethylene terephthalate is relatively low (3% relative to all diol components). Mol% or less).

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

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

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

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

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

  Examples of the Ge compound include amorphous germanium dioxide, crystalline germanium dioxide powder or ethylene glycol slurry, a solution obtained by heating and dissolving crystalline germanium dioxide in water, or a solution obtained by adding ethylene glycol to this and heat treatment. In particular, in order to obtain the polyester used in the present invention, it is preferable to use a solution in which germanium dioxide is dissolved by heating in water, or a solution in which ethylene glycol is added and heated. In addition, compounds such as germanium tetroxide, germanium hydroxide, germanium oxalate, germanium chloride, germanium tetraethoxide, germanium tetra-n-butoxide, and germanium phosphite can also be used. These polycondensation catalysts can be added during the esterification step. When a Ge compound is used, the amount used is 10 to 150 ppm, preferably 13 to 100 ppm, more preferably 15 to 70 ppm, and still more preferably 13 to 50 ppm as the residual amount of Ge in the polyester.

  Examples of Ti compounds include tetraalkyl titanates such as tetraethyl titanate, tetraisopropyl titanate, tetra-n-propyl titanate, tetra-n-butyl titanate, and partial hydrolysates thereof, titanium acetate, titanyl oxalate, titanyl oxalate, titanyl oxalate Sodium, titanyl oxalate, titanyl calcium oxalate, titanyl oxalate compounds such as titanium strontium oxalate, titanium trimellitate, titanium sulfate, titanium chloride, titanium halide hydrolyzate, titanium oxalate, titanium fluoride, titanium hexafluoride Titanium with potassium acid, ammonium hexafluorotitanate, cobalt hexafluorotitanate, manganese hexafluorotitanate, titanium acetylacetonate, hydroxy polyvalent carboxylic acid or nitrogen-containing polyvalent carboxylic acid Complex, complex oxide consisting of titanium and silicon or zirconium, reaction product of titanium alkoxide and phosphorus compound Reaction of phosphorus compound with reaction product of titanium alkoxide and aromatic polycarboxylic acid or its anhydride Examples of the reaction product obtained are listed. The Ti compound is added so that the amount of Ti remaining in the produced polymer is 0.1 to 50 ppm, preferably 0.5 to 10 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 in the range of 50 to 300 ppm, preferably 50 to 250 ppm, preferably 50 to 200 ppm, more preferably 50 to 180 ppm.

  Al compounds include aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride, aluminum carbonate, aluminum phosphate, aluminum phosphonate and other inorganic acid salts, aluminum n-propoxide, aluminum iso-propoxide Aluminum alkoxides such as aluminum n-butoxide and aluminum t-butoxide, aluminum chelate compounds such as aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide, trimethylaluminum, triethylaluminum, etc. Organic aluminum compounds and partial hydrolysates thereof, aluminum oxide, etc. It is. Of these, aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum hydroxide chloride and aluminum acetylacetonate are particularly preferred. The Al compound is added so that the residual amount of Al in the produced polymer is in the range of 5 to 100 ppm, preferably 10 to 50 ppm.

  Moreover, in manufacture of the polyester used by this invention, you may use together an alkali metal compound or an alkaline-earth metal compound as needed. 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 used in the present invention is at least one element selected from the group consisting of silicon, manganese, iron, cobalt, zinc, gallium, strontium, zirconium, niobium, molybdenum, indium, tin, hafnium, and thallium. You may contain the metal compound containing. 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 1 ton of produced polymer is in the range of 0.05 to 3.0 mol. These metal compounds can be added at any stage of the polyester formation reaction step.

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

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

  The melt polycondensation polyester obtained as described above is, 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 by a method of forming chips while cooling with cooling water.

Further, as the cooling water at the time of forming the melt polycondensed polyester into chips, it is preferable to use cooling water satisfying at least one of the following (2) to (5), and more preferably (2) to (5 It is most preferable to use water that satisfies all of the above.
Na ≦ 1.0 (ppm) (2)
Mg ≦ 1.0 (ppm) (3)
Si ≦ 2.0 (ppm) (4)
Ca ≦ 1.0 (ppm) (5)

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

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

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

  The shape of the polyester chip used in the present invention may be any of a cylinder shape, a square shape, a spherical shape or a flat plate shape. The average particle diameter is usually 1.0 to 4 mm, preferably 1.0 to 3.5 mm, and more preferably 1.0 to 3.0 mm. For example, in the case of a cylinder type, it is practical that the length is about 1.0 to 4 mm and the diameter is about 1.0 to 4 mm. In the case of spherical particles, it is practical that the maximum particle size is 1.1 to 2.0 times the average particle size and the minimum particle size is 0.7 times or more the average particle size. The weight of the chip is practically in the range of 2 to 40 mg / piece.

  The amount of diethylene glycol copolymerized in the polyester used in the present invention is 1.3 to 5.0 mol%, preferably 1.5 to 4.0 mol%, of the glycol component constituting the polyester. More preferably, it is 1.8-3.5 mol%, More preferably, it is 2.0-3.0 mol%, Most preferably, it is 2.0-2.9 mol%. When the amount of diethylene glycol exceeds 5.0 mol%, the thermal stability is deteriorated, the decrease in molecular weight becomes large at the time of molding, and the increase in acetaldehyde content and formaldehyde content becomes large, which is not preferable. On the other hand, when the diethylene glycol content is less than 1.0 mol%, the transparency of the obtained molded article is deteriorated.

  The acetaldehyde content of the polyester composition used in the present invention is 50 ppm or less, preferably 30 ppm or less, more preferably 10 ppm or less. In particular, when the polyester composition of the present invention is used as a material for a container for low flavor beverages such as mineral water, the acetaldehyde content of the polyester composition is 8 ppm or less, preferably 5 ppm or less, more preferably 4 ppm. The following is desirable. When the acetaldehyde content exceeds 50 ppm, the effect of flavor retention of the contents such as a molded article molded from this polyester composition is deteriorated. Further, these lower limits are preferably 0.1 ppm from the viewpoint of production.

  The formaldehyde content of the polyester composition used in the present invention is 20 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less. When the formaldehyde content is 20 ppm or more, the flavor and odor of contents such as a container molded from the polyester composition are deteriorated. In particular, when the polyester composition of the present invention is used as a material for containers for low flavor beverages such as mineral water, the formaldehyde content of the polyester composition is preferably 3 ppm or less, more preferably 2 ppm or less. It is desirable to be. The formaldehyde content of the molded body molded at 290 ° C. is 7 ppm or less, preferably 5 ppm or less, more preferably 3 ppm or less, and further preferably 2 ppm or less. When the formaldehyde content is 7 ppm or more, the flavor and odor of contents such as a container molded from this polyester composition are deteriorated.

  The content of the cyclic trimer of the polyester composition used in the present invention is 0.70% by weight or less, preferably 0.60% by weight or less, more preferably 0.50% by weight or less, particularly preferably 0.35. It is preferable that it is below wt%. The lower limit of the cyclic trimer content is 0.20% by weight or more, preferably 0.22% by weight or more, and more preferably 0.25% by weight or more from the viewpoint of economical production. When molding a heat-resistant hollow molded body or the like, heat treatment is performed in a heating mold. When the cyclic trimer content is 0.70% by weight or more, an oligomer on the surface of the heating mold is used. -Adhesion increases rapidly, and transparency of the obtained hollow molded object etc. deteriorates very much.

  In the method for producing a polyester preform of the present invention, the cyclic trimer increase when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less, preferably 0.3% by weight or less, more preferably It is desirable to use a polyester composition that is 0.1% by weight or less. When the amount of increase in cyclic trimer when melted at 290 ° C. for 60 minutes exceeds 0.40% by weight, the amount of linear monomer or cyclic trimer is included when the resin is melted when molding the molded body. Because the content of free low molecular weight compounds increases, the flavor retention of the contents of the molded product deteriorates, and the adhesion of oligomers to the surface of the heated mold increases rapidly, and the transparency of the resulting hollow molded product is extremely high Worse.

  The polyester composition in which the increase amount of the cyclic trimer when melted at a temperature of 290 ° C. for 60 minutes is 0.40% by weight or less is a polycondensation catalyst of at least one polyester among the polyesters constituting the polyester composition Can be produced by deactivation treatment.

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

As a hot water treatment method, polyester A, polyester B, or a polyester composition containing these as a main component, or a method of immersing polyester C, polyester D, or a polyester composition containing these as a main component in water or a shower. A method of applying water on these chips is exemplified. 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.
The water to be used is preferably water that satisfies at least one of the above (2) to (5), and most preferably water that satisfies all of (2) to (5).

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

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

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

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

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

  When the polyester composition is to be obtained by dry blending two kinds of polyester chips by the method as described above, if the variation of the mixing ratio of both is large, Variations in crystallization characteristics and the like occur. For this reason, characteristics such as acetaldehyde content, transparency, thickness, and the like of the obtained molded body vary, which becomes a big problem. In addition, when the polyester composition after dry blending is supplied to a dryer or a molding machine, or discharged from these devices, or when the polyester composition is transferred in a transfer pipe with a gas, etc. When moving the polyester, the blending ratio of the polyester may vary.

  The variation rate of the blend ratio of the polyester chips before the supply to the molding machine or the like or before the melt molding is within ± 5%, preferably within ± 3%, more preferably within ± 1%.

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

  The density of the polyester chip used in the present invention is 1.370 grams / cubic centimeter or more, preferably 1.380 grams / cubic centimeter or more, more preferably 1.390 grams / cubic centimeter or more, and particularly preferably 1.395 grams / cubic centimeter or more. It is desirable that Further, if it is attempted to obtain a chip having a density of 1.415 g / cubic centimeter or more, there is a problem in that chip fusion occurs during solid phase polymerization. When the density of the chip is less than 1.390 grams / cubic centimeter, the content of the cyclic trimer cannot be reduced to 0.7% by weight or less, and problems such as mold contamination occur. In the case of a certain heat resistant molded body, it is not preferable.

The difference in density of the polyester chips used in the present invention is within 0.025 grams / cubic centimeter, preferably within 0.02 grams / cubic centimeter, and more preferably within 0.01 grams / cubic centimeter. When the difference in density exceeds 0.025 g / cubic centimeter, when the molded product is produced from the polyester composition, the variation of the blending ratio in the time series direction becomes large. As a result, there is a problem that a molded product having large thickness spots, stretch spots and transparent spots is generated.
The polyester chip size and chip bulk density used in the present invention are as described above.

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

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

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

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

  Examples of the polyethylene resin blended in the polyester used in the present invention include ethylene homopolymer, ethylene, propylene, 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, and decene-1, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, styrene, Examples thereof include copolymers with vinyl compounds such as saturated 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.

  Examples of the polypropylene resin blended in the polyester used in the present invention include propylene homopolymer, 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. Or a copolymer with a diene such as hexadiene, octadiene, decadiene or dicyclopentadiene. Specific examples include propylene-based resins such as propylene homopolymer (atactic, isotactic, syndiotactic polypropylene), propylene-ethylene copolymer, propylene-ethylene-butene-1 copolymer.

Moreover, as alpha-olefin type resin mix | blended with the polyester used by this invention, the homopolymer of about C2-C8 alpha olefins, such as 4-methylpentene-1, those alpha olefins, and 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.

  Examples of the polyamide resin blended in the polyester used in the present invention include polymers of lactams such as butyrolactam, δ-valerolactam, ε-caprolactam, enantolactam, ω-laurolactam, 6-aminocaproic acid, 11 -Polymers of aminocarboxylic acids such as aminoundecanoic acid and 12-aminododecanoic acid, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, undecamethylenediamine, 2,2,4- or 2,4 Aliphatic diamines such as 1,4-trimethylhexamethylenediamine, alicyclic diamines such as 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xyl Diamines such as range amines and other aromatic diamines And dicarboxylic acid units such as aliphatic dicarboxylic acids such as glutaric acid, adipic acid, suberic acid and sebacic acid, cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid. Examples thereof include condensates and copolymers thereof. Specifically, for example, nylon 4, nylon 6, nylon 7, nylon 8, nylon 9, nylon 11, nylon 12, nylon 66, nylon 69, nylon 610 , Nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6 / MXD6, nylon MXD6 / MXDI, nylon 6/66, nylon 6/610, nylon 6/12, nylon 6 / 6T, nylon 6I / 6T Etc. These resins may be crystalline or amorphous.

Moreover, as a polyacetal resin mix | blended with polyester used by this invention, a polyacetal homopolymer and a copolymer are mentioned, for example. As the polyacetal homopolymer, the density measured by ASTM-D792 is 1.40 to 1.42 g / cm ³ , and the melt flow ratio (MFR) measured at 190 ° C. and load 2160 g is measured by ASTM D-1238. ) Is preferably in the range of 0.5 to 50 g / 10 min.
Moreover, as a polyacetal copolymer, the density measured by the measuring method of ASTM-D792 is 1.38 to 1.43 g / cm ³ , the melt flow ratio measured at 190 ° C. and the load of 2160 g by the measuring method of ASTM D-1238. A polyacetal copolymer having a (MFR) in the range of 0.4 to 50 g / 10 min is preferred. Examples of these copolymer components include ethylene oxide and cyclic ethers.

  The production of the polyester composition blended with the polyolefin resin or the like in the present invention is a method in which the resin such as the polyolefin resin is directly added to the polyester used in the present invention so that its content falls within the above range and melt kneaded. In addition to conventional methods such as a method of adding and 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, solid-phase polymerization At any stage, such as immediately after solid-phase polymerization, or in the process from the end of the manufacturing stage to the molding stage, it can be added directly as a granular material, or the polyester chip can be flowed It is also possible to use a method of mixing by a method such as contacting the resin member under conditions or a method of melt-kneading after the contact treatment.

  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.

Further, the polyester composition of the present invention includes polyamide, polyesteramide, low molecular weight amino group-containing compound, hydroxyl group-containing compound, hindered phenyl compound, hindered amine compound, benzotriazole compound, benzophenone compound as an aldehyde reducing agent. , Polyphenol compounds, phosphorus stabilizers, sulfur stabilizers, alkali metal salts, preferably polyamides, benzophenone compounds, polyester amides, phosphorus stabilizers, low molecular weight amino group-containing compounds, hydroxyl groups A containing compound, a benzophenone compound, a hindered phenyl compound, and a hindered amine compound can be blended. Most preferably, it is a polyamide, a polyesteramide, or a low molecular weight amino group-containing compound, and the haze of the obtained polyester molded article is good.

  Examples of the polyamide blended as the aldehyde reducing agent include at least one polyamide selected from aliphatic polyamide and partially aromatic polyamide.

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

As a preferable example of the partially aromatic polyamide, a structural unit derived from metaxylylenediamine or a mixed xylylenediamine containing metaxylylenediamine and 30% or less of the total amount of paraxylylenediamine and an aliphatic dicarboxylic acid is used. A metaxylylene group-containing polyamide containing at least 20 mol% or more, more preferably 30 mol% or more, particularly preferably 40 mol% or more in the molecular chain.
Further, the partially aromatic polyamide may contain a structural unit derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range.
Examples of these polyamides include homopolymers such as polymetaxylylene adipamide, polymetaxylylene sebacamide, polymetaxylylene speramide, and metaxylylenediamine / adipic acid / isophthalic acid copolymers, metaxylylene. / Paraxylylene adipamide copolymer, metaxylylene / paraxylylene piperamide copolymer, metaxylylene / paraxylylene azelamide copolymer, metaxylylenediamine / adipic acid / isophthalic acid / ε-caprolactam copolymer And metaxylylenediamine / adipic acid / isophthalic acid / ω-aminocaproic acid copolymer.

In addition, other preferable examples of the partially aromatic polyamide include at least 20 mol% or more of a structural unit derived from an aliphatic diamine and at least one acid selected from terephthalic acid or isophthalic acid, A polyamide containing 30 mol% or more, particularly preferably 40 mol% or more is preferred.
Examples of these polyamides include polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, hexamethylene diamine / terephthalic acid / isophthalic acid copolymer, polynonamethylene terephthalamide, polynonamethylene isophthalamide, nonamethylene diamine / terephthalic acid. / Isophthalic acid copolymer, nonamethylenediamine / terephthalic acid / adipic acid copolymer, and the like.

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

Polyester amides include 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. Examples of the acid component that can be used as a copolymerization component include aliphatic compounds such as sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, spellic acid, azelaic acid, undecanoic acid, undecanoic acid, dodecanedioic acid, and dimer acid Dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,3-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,2-cyclohexanedicarboxylic acid, orthophthalic acid, xylylene dicarboxylic acid, naphthalene Aromatic dicarboxylic acids such as dicarboxylic acids can be 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 composition or cannot be quantitatively extruded. Moreover, when exceeding 120 degreeC, when extending | stretching a polyester unstretched molded object, it will not be stretched | homogenized uniformly but a thickness spot etc. will arise and it is not preferable.

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, N, N′-1,6- Examples thereof include aromatic amine compounds such as hexanedibis (2-aminobenzamide) and 4,4′-diaminodiphenylmethane, triazine compounds such as melamine and benzoguanamine, and amino acids.

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

  Examples of the hindered phenyl compound include triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5 -Di-t-butyl-4hydroxy-phenylpropionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4hydroxy-phenylpropionate], N, N-hexamethylenebis ( 3,5-di-t-butyl-4hydroxyphenyl) propionate, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, octadecyl-3- (3,5-di-t -Butyl-4hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl) 4-hydroxybenzyl) benzene, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,2 -Thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and the like can be used, and these can be used alone or in combination of two or more. .

  Examples of the benzophenone compounds include 2,4-dihydroxybenzophenone, bis (5-benzol-4-hydroxy-2-methoxyphenyl) methane, 2,2′-dihydroxy-4-methoxybenzophenone, and 2,2′-dihydroxy-4. , 4'-dimethoxybenzophenone and the like, and those of the following formula. These can be used individually by 1 type or in combination of 2 or more types.

In formula (Ea-1), R ² represents an alkyl group, preferably one having 1 to 20 carbon atoms. Specific examples of the compound of the formula (Ea-1) include 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone and the like.

  Specific examples of the hindered amine compound include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly ((6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl) ((2,2,6,6-tetramethyl-4-piperidyl) imino) hexamethylene ((2, 2,6,6-tetramethyl-4-piperidyl) imino)) and the following formulas can be mentioned, and these can be used singly or in combination of two or more.

In the formula (F-3), x represents an integer of 1 or more. In formula (F-4), n represents an integer of 1 or more, preferably 1-20. Specific examples of the compound of formula (F-4) include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like.

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

The aldehyde reducing agent 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, based on 100 parts by weight of the polyester composition of the present invention. Can do.

  The aldehyde reducing agent can be blended by adding a predetermined amount of aldehyde reducing agent at any reaction stage from the production of a low-polymerization degree oligomer of polyester to the production of polyester polymer. For example, the aldehyde reducing agent may be added to a reactor such as an esterification reactor or a polycondensation reactor in an appropriate form such as a fine granule, powder, or melt, or from the reactor to a reactor in the next step. The aldehyde reducing agent or a mixture of the polyester and the polyester may be introduced in a molten state into a transport pipe for the polyester reactant. 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 composition and an aldehyde reducing agent by a conventionally well-known method, or the method of mixing an aldehyde reducing agent with the mixture of 2 or more types of polyester. For example, polyamide chips and two types of polyester chips with different IVs are dry blended with a tumbler, V-type blender, Henschel mixer, etc., and the dry blended mixture once with a single screw extruder, twin screw extruder, kneader, etc. Examples include those obtained by melting and mixing as described above, and those obtained by subjecting chips from the molten mixture to solid phase polymerization in a high vacuum or inert gas atmosphere as necessary.
Further, a method in which a solution in which the polyamide or the like is dissolved in a solvent such as hexafluoroisopropanol is adhered to the surface of the polyester chip, and the polyester is collided with the member in a space where the polyamide member is present. Examples include a method of attaching the polyamide to the surface of the polyester chip.

  According to the method for producing a polyester preform of the present invention, a preform such as an injection-molded preform or an extrusion-molded preform for a stretched hollow molded body, or a preform such as an unstretched sheet for a stretched sheet or stretched film. Can be obtained.

  In the method for producing a polyester preform of the present invention, the temperature of the molten resin is, for example, 260 to 295 ° C., preferably 262 to 290 by heating a barrel, a die, a hot runner, or the like of an injection molding machine or an extrusion molding machine. Although it is preferable to set it in a range of 265 ° C., more preferably 265 to 285 ° C., it is not limited to this. Here, the molten resin temperature refers to a temperature obtained by immediately measuring, for example, a thermocouple thermometer with a resin injected or extruded from a nozzle tip or a die outlet of an injection molding machine or the like.

  Further, these preforms can be obtained by a conventionally known molding method to obtain a hollow molded body such as a bottle, a stretch blow hollow molded body, a uniaxially stretched film, and a biaxially stretched film. Cups and trays can also be obtained by pressure forming or vacuum forming.

  In order to produce a stretched hollow molded body, the foam molded by the above-mentioned polyester preform fabrication method can be stretch blow molded, and an apparatus conventionally used in blow molding of PET can be used. Specifically, for example, the preform is processed as it is or after the plug and bottom portions thereof are processed, and then reheated, and a biaxial stretch blow molding method such as a cold parison method is applied. The stretching temperature is usually 80 to 125 ° C., preferably 90 to 110 ° C., and the stretching ratio is usually 1.3 to 3.5 times in the longitudinal direction and 2 to 5 times in the circumferential direction. In this case, the stretching speed in the axial direction is 3.0 times / second or more, particularly 4.0 times / second or more, and the stretching speed in the circumferential direction is 5.0 times / second or more, particularly 6.0 times / second. High-speed stretching for a second or more is particularly suitable. Furthermore, as the pressurized fluid to be blown at the time of blow molding, it is preferable to use a high-temperature fluid that is maintained at a temperature that is at least 10 ° C. higher than the preform temperature.

  The hollow molded body thus obtained can be used as it is, but generally in the case of beverages that require hot filling, such as fruit juice beverages and oolong teas, it is generally heat-set in a blow mold. To give heat resistance. The heat setting is usually performed at 100 to 200 ° C., preferably 120 to 180 ° C. for several seconds to several hours, preferably several seconds to several minutes, under tension by compressed air or the like.

  After the heat setting is completed as described above, the stretched blow pressurized fluid is switched to the internal cooling fluid, the inside is cooled, and after the cooling is completed, the stretched and heat-set stretched product is taken out from the mold. As the cooling fluid, various gases cooled to an appropriate temperature, for example, nitrogen, air and carbon dioxide gas maintained at -40 ° C. to room temperature are preferably used. Other liquefied gases such as liquefied nitrogen gas, liquefied carbon dioxide gas, liquefied trichlorofluoromethane gas, liquefied dichlorodifluoromethane gas, and other liquefied aliphatic hydrocarbon gases can also be used.

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

Moreover, the manufacturing method of the polyester preform of this invention is applicable also to manufacture of the preform used for manufacture of the heat resistant bottle by the two-stage blow molding method provided with a primary blow molding process and a secondary blow molding process. be able to.
In the case of the two-stage blow molding method of PET, a preform obtained by crystallizing the plug portion as described above in the primary blow molding step is 1.0 to 1.0 to the final product volume at the same stretching temperature as described above. The biaxially stretched blow molding is performed about twice, and then the obtained primary molded body is heated at about 100 to 250 ° C. and then subjected to secondary blowing in a mold of about 80 to 200 ° C. in the secondary blow molding step.

  Furthermore, the method for producing a polyester preform according to the present invention can also be applied to a so-called compression molding method in which a preform obtained by compression molding a molten mass cut after melt extrusion of a polyester is obtained.

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

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

  Further, when a film is produced from the polyester composition used in the present invention, calcium carbonate, magnesium carbonate, barium carbonate is contained in the polyester in order to improve handling properties such as slipping property, winding property, and blocking resistance. , Inorganic particles such as calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, organic salt particles such as terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, magnesium, divinylbenzene, styrene, acrylic Inactive particles such as crosslinked polymer particles such as acid, methacrylic acid, acrylic acid, or vinyl monomers of methacrylic acid, or copolymers, can be incorporated into the polyester used in the present invention.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
The main characteristic value measurement methods will be described below.
The composition and characteristics of each polyester (excluding (4) to (7)) 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 composition 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, adjusted to a constant volume with 10 ml of dimethylformamide, and the cyclic trimer was quantified by high performance liquid chromatography. The cyclic trimer content of the polyester composition was a weighted average value calculated from the cyclic trimer content of the constituting polyester.

(4) Acetaldehyde content of polyester (hereinafter referred to as “AA content”)
Sample / distilled water = 1 g / 2 cc of glass ampoule substituted with nitrogen was sealed and subjected to extraction treatment at 160 ° C for 2 hours. After cooling, acetaldehyde in the extract was measured by high-sensitivity gas chromatography. The concentration was expressed in ppm. The acetaldehyde content of the polyester composition was a weighted average value calculated from the acetaldehyde content of the constituting polyester. In the case of the chip, the hollow molded body is a sample collected to a size of about 2 mm from the plug portion, the sheet is the central sample, and the compression molded preform is the central sample.

(5) Increasing amount of cyclic trimer at the time of melting polyester (△ CT amount)
A sample was taken from a 3 mm thick plate molded at 290 ° C. by the method of (11), dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours, and then 3 g of the sample was placed in a glass test tube and a nitrogen atmosphere It is immersed in an oil bath at 290 ° C. for 60 minutes and melted. The increase amount of the cyclic trimer at the time of melting is obtained by the following equation.
The cyclic trimer content of the plate was used as the cyclic trimer content before melting.
Increase amount of cyclic trimer at the time of melting (wt%) =
Cyclic trimer content after melting (wt%)-cyclic trimer content before melting (wt%)

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

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

(7) 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 (6), the fines collected from the polyester were frozen and pulverized, dried under reduced pressure at 25 ° C. for 3 days, and 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 melting 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.

(8) 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 sample from the center of a 2 mm thick plate of the molded plate of (12) below. The temperature was raised at a rate of temperature rise of 20 ° C./minute and held at 290 ° C. for 3 minutes, then the temperature was lowered from 290 ° C. to 240 ° C. at 10 ° C./minute, and further from 240 ° C. to 130 ° C. at 7 ° C./minute. The temperature dropped. The peak temperature of the crystallization peak observed at the time of temperature rise is defined as the crystallization temperature (Tc1) at the time of temperature increase, and the peak temperature of the crystallization peak observed at the time of temperature decrease is defined as the crystallization temperature at the time of temperature decrease.

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

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

(11) Haze (Fraction%)
A sample was cut from the body of the stretched hollow molded body (thickness: about 0.4 mm) of (12) below, and measured with a model NDH2000, a Nippon Denshoku Co., Ltd. haze meter, with 5 sheets stacked.

(12) Molding of Stepped Molding Plate Polyester obtained by vacuum drying for about 16 hours at 140 ° C. and 0.1 mmHg or less using a vacuum dryer was obtained by using an injection molding machine M-150C-DM type injection molding machine manufactured by Meiki Seisakusho. 2 having a gate part (G) as shown in FIG. 2 (thickness of A part = 2 mm, thickness of B part = 3 mm, thickness of C part = 4 mm, thickness of D part = 5 mm, E part of A stepped molded plate having a thickness of 10 mm and a thickness of F portion of 11 mm was injection molded.
Polyester previously dried under reduced pressure using a vacuum dryer DP61 manufactured by Yamato Kagaku was used, and a dry inert gas (nitrogen gas) purge was performed in the molding material hopper to prevent moisture absorption during molding. The plasticizing conditions of the M-150C-DM injection molding machine are: 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 The temperature was set at 290 ° C. The injection conditions are 20% for injection speed and holding pressure, and the injection pressure and holding pressure are adjusted so that the weight of the molded product is 146 ± 0.2g. In this case, the holding pressure is 0.5MPa lower than the injection pressure. It was adjusted.

The upper limit of the injection time and pressure holding time is set to 10 seconds and 7 seconds, respectively, and the cooling time is set to 50 seconds. The total cycle time including the time for taking out the molded product is about 75 seconds.
Although the temperature of the mold is always controlled by introducing cooling water having a water temperature of 10 ° C., the mold surface temperature at the time of stable molding is around 22 ° C.
The test plate for evaluating the molded product characteristics was arbitrarily selected from the 11th to 18th shots of the stable molded product after the molding material was introduced and the resin was replaced.
The molding temperature refers to the set temperature of the barrel including the nozzle.

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

(13) Molding of hollow molded body The polyester is dried with a dryer using dehumidified air, and the cylinder and hot so that the resin temperature becomes 255 ° C. to 300 ° C. with an M-150C-DM injection molding machine manufactured by each machine manufacturer. The temperature of the runner was changed, the molding cycle was changed, and the injection pressure was set to 1.8 to 2.3 kg / cm ² , and the preform (outer diameter 29.4 mm, length 145.5 mm, wall thickness about 3. 7 mm, weight 60 g). The surface temperature of the mold when molding is stable is around 22 ° C.
The plug parts of these preforms were heat-treated for 180 seconds with a homemade infrared heater, and then a mold pin was inserted to heat-crystallize the plug part. Next, this preform was biaxially stretched and blown with a LB-01E molding machine manufactured by CORPOPLAST, and then heat-set in a mold set at about 150 ° C. for about 5 seconds to form a container having a capacity of 1500 cc. The stretching temperature was controlled at 100 ° C.
The molten resin temperature was measured by bringing a thermocouple thermometer into contact with the molten resin injected from the nozzle tip of the injection molding machine.

(14) Randomness (R)
Each time the conditions are changed by the injection molding machine of (13), a sample is cut from the center of the body of a preform obtained by molding the following PET / PEN mixture for grasping molding conditions, and measured by the NMR method.
1) Measuring device unity-500 manufactured by Barian
2) Measuring method
In accordance with the method described in Mark E. Stewart, A. James Cox, D. Mark Naylor: Polymer Vol. 34, P. 4060 (1993), the ethylene proton of the ethylene glycol chain was measured and obtained by calculation.
3) Calculation of randomness (R) The blockiness (randomness) is expressed by the following equation (2).

R = {1 / Lm (PEN) + 1 / Ln (PET)} (2)

Here, Lm (PEN): average chain length (m) of resin mainly composed of ethylene naphthalate unit
Ln (PET): average chain length (n) of resin mainly composed of ethylene terephthalate units as repeating units

The randomness (R) is between 0 and 2, and the following can be seen from the equation (2).
Randomness 0: Complete block copolymer
Randomness 1: Completely random copolymer
Randomness 2: Completely alternating copolymer

(15) Appearance of Hollow Molded Body Twenty hollow molded bodies from the tenth molding start of (13) were visually observed and evaluated as follows.
◎: Transparent and no appearance problem △: There is a little whitened flow pattern or whitened product in the hollow molded body ×: White flowed pattern or whitened product in the hollow molded body

(16) Shape and dimensions of the plug portion of the preform for the hollow molded body The shape and dimensions of the preform plug portion crystallized in (13) 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.

(17) Sensory test Put boiling distilled water into the hollow container obtained in (13) above, hold for 30 minutes after sealing, cool to 50 ° C and let stand at the same temperature for 1 week. After opening, test for flavor, odor, etc. Went. Use distilled water as a blank for comparison. The sensory test was carried out by 10 panelists according to the following criteria, and the average values were compared.
(Evaluation criteria)
◎: Feel no strange taste or smell ○: Feel a slight difference from the blank △: Feel a difference from the blank ×: Feel a considerable difference from the blank XX: Feel a very large difference from the blank

(PET for grasping molding conditions)
Unipet RT553P (IV = 0.84) manufactured by Nippon Unipet Corporation was used.

(PEN for grasping molding conditions)
943 parts of 2,6-dimethylnaphthalate, 65.1 parts of dimethyl terephthalate, 573 parts of ethylene glycol, 0.31 part of manganese acetate tetrahydrate, 0.085 part of cobalt acetate tetrahydrate Was used for transesterification at 180 to 245 ° C. in accordance with a conventional method, and methanol was distilled off. Then, 0.185 part of phosphoric acid was added and reacted for several minutes. To this reaction product, 0.10 parts of germanium dioxide was added, and a melt polymerization reaction was performed at 285 ° C. under a reduced pressure of 0.5 mmHg or less. A resin with IV = 0.55 was obtained. The chip size was adjusted to RT553P.
(PET / PEN mixture for grasping molding conditions)
A uniform mixture of 50 parts by weight / 50 parts by weight of PET and PEN was dried under reduced pressure at 140 ° C. and 0.1 mmHg or less for about 16 hours.

(Polyester 1 (Pes1))
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. Moreover, 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 continuously supplied separately to the first esterification reactor. This reaction product was sent to the second esterification reactor, and the reaction was carried out with stirring at about 260 ° C. and 0.05 kg / cm ² G to a predetermined reactivity. The esterification reaction product is continuously sent to the first polymerization reactor under stirring at about 265 ° C. and 25 torr for 1 hour, then in the second polymerization reactor under stirring at about 265 ° C. and 3 torr for 1 hour, and further Polymerization was conducted at about 275 ° C. and 0.5 to 1 torr with stirring in the third polymerization reactor. The intrinsic viscosity (IV) of the obtained PET resin was 0.53.

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

The obtained PET has an intrinsic viscosity of 0.68 deciliter / gram, an acetaldehyde (AA) content of 3.8 ppm, a cyclic trimer content of 0.35 wt%, a fine content of about 50 ppm, and a chip density of 1 398 g / cm ³ . The properties of the obtained PET are shown in Table-1.

(Polyester 2A (Pes2A), 3 (Pes3))
Polyesters 2A and 3 were obtained by reacting in the same manner as in Example 1 except that the polycondensation catalyst addition amount and the solid phase polymerization time were changed. The properties of the obtained PET are shown in Table-1.

(Polyester 2B (Pes2B))
The reaction was carried out in the same manner as Pes1 except that the amount of polycondensation catalyst added was reduced and the final polycondensation time was shortened to obtain a molten polycondensation prepolymer with IV = 0.48, which was changed to a chip size smaller than Pes1. After chipping, the mixture was put into a rotary reduced pressure solid phase polymerization apparatus without fine removal, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then subjected to solid phase polymerization at 210 ° C. After the solid phase polymerization, fines were not removed in the sieving step. The properties of the obtained PET are shown in Table-1.
(Polyester 4 (Pes4))
A solid phase polymer was obtained by reacting in the same manner as in Example 1 except that the esterification conditions, polycondensation catalyst addition amount, and chip size were changed. The properties of the obtained PET are shown in Table-1.

(Polyester 5 (Pes5))
A prepolymer was obtained by melt polycondensation in the same manner as in Example 1 except that the esterification conditions, polycondensation catalyst addition amount, and chip size were changed. The obtained prepolymer was put into a rotary reduced pressure solid phase polymerization apparatus without fine removal, crystallized at 70 to 160 ° C. under reduced pressure while rotating, and then subjected to solid phase polymerization at 210 ° C. After the solid phase polymerization, fines were not removed in the sieving step. The properties of the obtained PET are shown in Table-1.

(Polyester 6 (Pes6), 7 (Pes7))
Polyesters 6 and 7 were obtained by reacting in the same manner as in Example 1 except that an ethylene glycol solution of titanium tetrabutoxide and an ethylene glycol solution of magnesium acetate tetrahydrate were used as the polycondensation catalyst. No ethylene glycol phosphate solution was added.
The properties of the obtained PET are shown in Table-1.

(Polyester 8 (Pes8), 9 (Pes9))
Using a mixture of terephthalic acid / isophthalic acid = 98.5 parts by weight / 1.5 parts by weight as a raw material, using an ethylene glycol solution of antimony trioxide and an ethylene glycol solution of cobalt acetate as a polycondensation catalyst, Polyesters 9 and 10 were obtained by reacting in the same manner as in Example 1 except that the temperature was 203 ° C.
The properties of the obtained PET are shown in Table-1.

(Polyester 10 (Pes10), 11 (Pes11))
As the polycondensation catalyst, the reaction was carried out in the same manner as in Example 1 except that an ethylene glycol solution of basic aluminum acetate, Irganox 1222 (manufactured by Ciba Specialty Chemicals) and an ethylene glycol solution in which ethylene glycol was heat-treated in advance were used. Thus, polyesters 10 and 11 were obtained. No ethylene glycol phosphate solution was added.
The properties of the obtained PET are shown in Table 2.

(Polyester 12 (Pes12))
The polyester 2 is continuously charged into the following water treatment tank controlled at a treatment water temperature of 95 ° C. from the supply port (1) at the upper part of the treatment tank at a rate of 50 kg / hour 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 sampled before the ion exchange water inlet (9) of the water treatment apparatus has a particle content of about 1800 particles / 10 ml, a sodium content of 0.02 ppm and a magnesium content of 0.1. 05 ppm, calcium content is 0.03 ppm, silicon content is 0.10 ppm, and the number of particles having a particle size 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 2 described in Table 1, except that the cyclic trimer increase amount (ΔCT amount) at the time of melting is 0.15% by weight.

(Polyester 13 (Pes13))
Polyester 3 was treated with water in the same manner as described above to obtain polyester 11.
The properties of the obtained PET are the same as the properties of polyester 3 described in Table 1, except that the cyclic trimer increase amount (ΔCT amount) upon melting is 0.16% by weight.

(Polyamide (Pam))
Toyobo nylon MXD6 resin (T640) manufactured by Toyobo Co., Ltd. was used.

Example 1
The polyester composition obtained by blending the above polyester 1 and polyester 3 pellets in a ratio of 8: 2 was injected by the method (13) under the conditions of a molten resin temperature of 280 ° C. and a molding cycle time of 55 seconds. Evaluation was performed using a preform and a hollow molded container obtained by molding. The results are shown in Table 2.
The randomness of the preform from the mixture for grasping molding conditions obtained under the same conditions as described above was 0.21.
There is no problem in the shape and size of the preformed body plug after crystallization, and the stretched hollow molded body has a good AA content of 12.5 ppm and a haze of 6.8%. There was no problem.

(Examples 2, 3, and 4)
A polyester composition having the same composition obtained by blending the pellets of polyester 2 and polyester 3 at a ratio of 7: 3 was the same as in Example 1 except that the molten resin temperatures were changed to 270 ° C., 280 ° C., and 290 ° C. The evaluation was carried out. The results are shown in Table 2.
All the evaluated characteristics were as good as in Example 1.

(Example 5)
According to the composition shown in Table 2, the polyester composition of Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

(Example 6)
According to the composition shown in Table 2, the polyester composition of Example 6 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

(Example 7)
Phosphoric acid is coated on the chip surface of a 7: 3 mixture of polyester 6 and polyester 7 so that the molar ratio of P content to Al content (P / Ti) is about 1.7. Evaluation was performed. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

(Example 8)
According to the composition shown in Table 2, the polyester composition of Example 8 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

Example 9
According to the composition shown in Table 2, the polyester composition of Example 9 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

(Example 10)
Phosphoric acid is sprayed on the chip surface of a 7: 3 mixture of polyester 10 and polyester 11 so that the molar ratio of P content to Al content (P / Al) is about 1.7. Evaluation was performed. The results are shown in Table 2. All the evaluated characteristics were as good as in Example 1.

(Comparative Example 1)
As shown in Table 2, the polyester 4 of Comparative Example 1 was evaluated in the same manner as in Example 1.
Obviously, the shape and dimensions after crystallization of the preformed body plug part of Comparative Example 1 are insufficiently crystallized and poorly shaped, and the stretched molded product has a high AA content and haze, The test was not very good either. The results are shown in Table 2.

(Comparative Example 2)
The polyester compositions shown in Table 2 were evaluated in the same manner as in Example 1 except that the molten resin temperature was increased and the molding cycle was extended. The results are shown in Table 2.
Among the properties evaluated, the AA content was high and the sensory test was a problem.

(Comparative Example 3)
The polyester compositions shown in Table 2 were evaluated in the same manner as in Example 1 except that the molding cycle was extended. The results are shown in Table 2. Among the properties evaluated, the AA content was high and the sensory test was a problem.

(Comparative Example 4)
As shown in Table 2, the polyester composition of Comparative Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All characteristics were problematic.

(Comparative Example 5)
As shown in Table 2, the polyester composition of Comparative Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 2. All characteristics were problematic.

(Example 11)
Evaluation was conducted in the same manner as in Example 1 on a polyester composition in which 100 parts by weight of the polyester mixture of Example 2 was blended with 1 part by weight of the polyamide.
The AA content of the stretched hollow molded article was greatly improved to 7.3 ppm, the haze was 8.8%, the appearance was ◎, and the sensory test was ◎, which was as good as in Example 1.

(Examples 12 to 16)
According to the composition shown in Table 3, the polyester compositions of Examples 12 to 16 were extruded from a die onto a cooling roll having a surface temperature of about 20 ° C. at a molten resin temperature of 275 ° C. using a sheet molding extruder. A sheet having a thickness of 5 mm was obtained. However, the randomness of the preform from the mixture for grasping molding conditions obtained under the same conditions was 0.30. The AA content and appearance of the sheet were all satisfactory.
In addition, the external appearance of the sheet | seat was observed visually and evaluated as follows.
◎: Transparent and no appearance problem △: Streaky whitened flow pattern ×: Poor transparency and rough surface

(Comparative Example 6)
As shown in Table 3, the polyester 4 of Comparative Example 6 was evaluated in the same manner as in Example 12.
Obviously, the AA content was high and the appearance was also a problem as compared with the examples.

(Comparative Examples 7 and 8)
The polyester compositions shown in Table 3 were evaluated in the same manner as in Example 12 except that the molten resin temperature and the melt residence time were changed. The results are shown in Table 3.
In these comparative examples, the AA content was high and problematic.

(Comparative Example 9)
The polyester composition of Comparative Example 9 shown in Table 3 was evaluated in the same manner as in Example 12 except that the melt residence time was changed. The results are shown in Table 3.
In these comparative examples, the AA content was high, and the appearance was poor.

(Comparative Example 10)
As shown in Table 3, the polyester composition of Comparative Example 10 was evaluated in the same manner as in Example 12.
Obviously, the AA content was high and the appearance was poor as compared with the Examples.

   According to the present invention, the production of aldehydes such as acetaldehyde at the time of molding is suppressed, and a preform having an excellent crystallization rate and an appropriate crystallization speed is efficiently produced by high-speed molding. And a biaxially-stretched or biaxially-stretched blow molding of the obtained preform, or heat-fixed thereafter, thereby reducing acetaldehyde content and excellent flavor retention, A biaxially stretched film or a hollow molded article excellent in transparency, mechanical properties such as elastic modulus and tensile strength, and a method for producing a stretched molded article excellent in heat fixability can be provided.

Plan view of stepped plate Side view of stepped plate It is the schematic of the water treatment apparatus used in the Example.

Explanation of symbols

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

Claims (9)

    A method for producing a polyester preform comprising molding a polyester composition comprising at least two polyesters mainly composed of ethylene terephthalate as a main repeating unit, the method comprising 50 parts by weight of polyethylene terephthalate, The intrinsic viscosity between at least two of the above polyesters under melt molding conditions where the degree of randomness (R) of the molded product obtained by molding a molding condition grasping mixture comprising 50 parts by weight of polyethylene naphthalate is 0.50 or less A polyester preform is produced by kneading and molding the polyester composition having a difference of 0.05 to 0.30 deciliter / gram. As the polyester composition, a polyester composition containing the following polyester A and polyester B as main components, and a difference in crystallization temperature when the temperature of polyester A is lowered from that of polyester B is within 20 ° C. The method for producing a polyester preform according to claim 1, wherein the polyester preform is used.
Polyester A: A polyester having an intrinsic viscosity IV _A of 0.60 to 0.80 deciliter / gram, an acetaldehyde content of 10 ppm or less, and a crystallization temperature measured by DSC of 160 to 200 ° C.
Polyester B: Polyester having an intrinsic viscosity IV _B of 0.73 to 0.95 deciliter / gram, an acetaldehyde content of 10 ppm or less, and a crystallization temperature measured by DSC of 160 to 200 ° C. The polyester composition includes the following polyester C and polyester D as main components, the difference between the chip bulk density of polyester C and the chip bulk density of polyester D is within 0.10 g / cubic centimeter, and when the temperature of polyester C falls 2. The method for producing a polyester preform according to claim 1, wherein a polyester composition having a difference between the crystallization temperature of the polyester and the crystallization temperature when the temperature of the polyester D is lowered is 15 ° C. or less.
Polyester C: Intrinsic viscosity IV _C is 0.60 to 0.80 deciliter / gram, bulk density is 0.80 to 0.97 gram / cubic centimeter, and crystallization temperature when measured by DSC is 140 to 180 ° C. A polyester having a crystallization temperature of 160 to 190 ° C. when the temperature is lowered.
Polyester D: Intrinsic viscosity IV _D is 0.73 to 0.95 deciliter / gram, bulk density is 0.80 to 0.97 gram / cubic centimeter, crystallization temperature is 140 to 180 ° C. at the time of temperature rise measured by DSC, A polyester having a crystallization temperature of 160 to 190 ° C. when the temperature is lowered.   The method for producing a polyester preform according to any one of claims 1 to 3, wherein a polyester composition having an acetaldehyde content of 10 ppm or less is used.   The method for producing a polyester preform according to any one of claims 1 to 4, wherein a polyester composition having a cyclic trimer content of 0.70% by weight or less is used.   The polyester preform according to any one of claims 1 to 5, wherein the polyester composition has a cyclic trimer increase amount of 0.40 wt% or less when melted at a temperature of 290 ° C for 60 minutes. Body manufacturing method.   The polyester composition containing 0.1 ppb to 1000 ppm of at least one resin selected from the group consisting of polyolefin resin, polyamide resin and polyacetal resin is used. A method for producing a polyester preform.   A method for producing a polyester stretch-molded product, wherein the polyester preform obtained by the production method according to claim 1 is stretched in at least one direction. A polyester preform obtained by biaxially stretch-blow molding the polyester preform obtained by the production method according to any one of claims 1 to 7, and heat-fixing the stretch-molded body after stretch molding as necessary. A method for producing a hollow molded body.

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