JPH08239462A - Copolyester and molding made thereof - Google Patents

Abstract

PURPOSE: To obtain a polyester having a high melt viscosity and suited to produce a blow molding by especially extrusion blow molding by subjecting a prepolymer made from terephthalic acid, ethylene glycol, a hydroxycarboxylic acid, etc., to a solid state polymerization. CONSTITUTION: A reactant mixture mainly consisting of a di-carboxylic acid component based on terephthalic acid or its esterifiable derivative, a diol component based on ethylene glycol and 0.01-1mol%, based on the total number of moles of the dicarboxylic acid component and the hydroxycarboxylic acid, hydroxydicarboxylic acid represented by formula I is esterified or transesterified, the formed ester is subjected to a melt polycondensation reaction to form a prepolymer, and this prepolymer is subjected to a solid state polymerization reaction to obtain the object polyester. This polyester mainly consists of diol units chiefly derived from ethylene glycol and dicarboxylic acid units chiefly derived from terephthalic acid and contains 0.01-1mol% units of formula II. In the formulas X is -CH2 CH2 - or the like; and n is 1-7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester, a method for producing the same, a method for producing a molded article using the copolyester and a molded article obtained thereby. ,
It has a high melt viscosity, yet exhibits a low viscosity at high shear rates and a high viscosity at low shear rates, showing non-Newtonian properties,
It is suitable for various types of melt molding, and particularly suitable for producing hollow molded articles by extrusion blow molding.

[0002]

2. Description of the Related Art Polyester resins such as polyethylene terephthalate are excellent in various properties such as transparency, mechanical properties, gas barrier properties and flavor barrier properties, and also residual monomers and harmful additives when formed into molded products. As it replaces the vinyl chloride resin that has been widely used in the conventional manufacturing of containers, juice, soft drink, seasoning, oil, cosmetics, detergent, In recent years, it has been widely used as a hollow container for filling other products.

As a typical molding method for manufacturing a hollow molded article such as a container from plastic, (1) a melted plasticized resin is extruded as a cylindrical parison through a die orifice, and the parison is in a softened state. An extrusion blow molding method in which a fluid such as air is blown inside by sandwiching it with a mold; and (2) a molten resin is injected into the mold to once mold a sealed parison (preform), and then There are two types of injection blow molding methods, in which is inserted into a blow mold and a fluid such as air is blown to perform molding.

Of the above-mentioned molding methods, the former extrusion blow molding method is simpler in process than the latter injection blow molding method, and does not require a high-level technique for producing and molding a mold. In addition, the equipment cost and die manufacturing cost are low, making it suitable for high-mix low-volume production. Moreover, the extrusion blow molding method has an advantage that it is possible to manufacture a molded product having a complicated shape including a fine product, a deep product, a large product, a handle, and the like.

From this point of view, various attempts have conventionally been made to carry out extrusion blow molding using a general-purpose polyester resin such as polyethylene terephthalate or polybutylene terephthalate. However, general-purpose polyester resins generally have a low melt viscosity, Therefore, when extrusion blow molding is attempted, it is difficult for the parison after extrusion to drastically draw down and be shaped. Moreover, there is a problem that crystallization is likely to occur at the time of blowing after extrusion, transparency is impaired, and improper shaping occurs. And the above-mentioned inconvenience resulting from such low melt viscosity and crystallization easily occurring in a general-purpose polyester resin such as polyethylene terephthalate is usually 20 cm or more in length required for manufacturing a large hollow molded article. It is particularly remarkable in extrusion blow molding for extruding a long parison. Therefore, it is practically extremely difficult to obtain a molded product, particularly a large hollow molded product, which has a uniform shape and size and is excellent in transparency by extrusion blow molding using a general-purpose polyester resin such as polyethylene terephthalate. is there.

Therefore, for the above reasons, vinyl chloride resins and polyolefins have conventionally been mainly used in extrusion blow molding because they have a high melt viscosity and do not cause remarkable drawdown of the parison extruded in the molten state. Came. However, extrusion blow-molded products manufactured using vinyl chloride resin have problems in hygiene and safety due to the elution of harmful additives such as plasticizers and metal stabilizers. There is a problem that it produces toxic gas when incinerated, and its use tends to decrease mainly in Europe. In addition, when extrusion blow molding is performed using a polyolefin such as polyethylene, there is a drawback in that white turbidity due to crystals is generated in the molded product and the transparency and appearance of the molded product are likely to be poor.

Therefore, for the reasons described above,
Proposals regarding polyester resins suitable for extrusion blow molding have hitherto been made. As such a conventional technique, a dicarboxylic acid component such as terephthalic acid or an ester-forming derivative thereof and a diol component such as ethylene glycol are subjected to an esterification reaction or an ester reaction. After an exchange reaction to produce a low polymer, a general-purpose crosslinking agent such as trimethylolpropane, pentaerythritol, or trimellitic acid is reacted with this to form a polycondensation reaction to form a prepolymer. A method for producing polyester for extrusion blow molding by phase polymerization (Japanese Patent Laid-Open No. 54-137).
No. 095, JP-A-54-163962 and JP-A-55-92730); and a method of copolymerizing isophthalic acid, cyclohexanedimethanol or the like during the production of polyethylene terephthalate, polybutylene terephthalate, etc .; Bisphenol A And the like, a method for producing a modified polyester by adding the ethylene oxide adduct of (1) to polyethylene terephthalate, polybutylene terephthalate, etc. (see JP-A-5-65338); and the like are known.

However, trimethylolpropane,
The polyester obtained by the above-mentioned prior art using a general-purpose cross-linking agent such as pentaerythritol and trimellitic acid is produced by the formation of spherulites due to the increase in crystallization rate.
Molded products such as extrusion blow-molded products obtained from this are markedly whitened and lack transparency, and in some cases gel-like substances derived from the crosslinked structure are generated, and the appearance of the molded products appears as lumps and the like appear in the molded products. It has the drawback of being damaged.

Based on the above-mentioned conventional technique, the present inventors produced a polyethylene terephthalate type copolymerized polyester having a lowered melting point by copolymerizing isophthalic acid and cyclohexanedimethanol, and prepared this copolymerized polyester. I tried to perform extrusion blow molding by setting the melt extrusion temperature to a lower temperature than before, but because the melt viscosity at the extrusion temperature was not sufficiently high, the drawdown of the parison after extrusion was remarkable during extrusion blow molding. However, it was difficult to shape, and extrusion blow molding could not be performed smoothly. Moreover, the copolyester of this prior art co-polymerized with isophthalic acid or cyclohexanedimethanol cannot be solid-phase polymerized due to its low melting point, or even if solid-phase polymerization is possible, the solid-state polymerization The rate was extremely slow and the degree of polymerization did not increase sufficiently, so that the molded articles produced from the polyester had large thickness unevenness and poor transparency.

Further, even in the above-mentioned conventional copolyester obtained by copolymerizing the ethylene oxide adduct of bisphenol A, the extrusion blow moldability is not sufficiently good as a result of the additional experiment by the present inventors. It was In addition to the above-mentioned prior arts, the present inventors tried to produce polyethylene terephthalate having a high degree of polymerization by solid phase polymerization, but the solid phase polymerization rate was extremely slow, and extrusion blow molding was performed. It has been found that polyethylene terephthalate having a sufficiently high degree of polymerization and a melt viscosity suitable for, for example, cannot be efficiently obtained in a short time and is not practical in terms of productivity.

[0011]

Therefore, an object of the present invention is to have a high melt viscosity and excellent melt moldability,
Particularly, when used in extrusion blow molding, a remarkable drawdown of the extruded parison does not occur, it is excellent in blow moldability, and a polyester that can smoothly manufacture a molded product having a target shape and dimensions with high accuracy is provided. It is to be. And an object of the present invention is to provide a polyester capable of smoothly producing a molded article having excellent transparency and heat resistance by melt molding, particularly extrusion blow molding. Another object of the present invention is to provide a method capable of producing a polyester having the above-mentioned various excellent properties in a short time with high productivity. Further, it is an object of the present invention to provide a method for producing a molded article by carrying out melt molding, particularly extrusion blow molding, using the polyester having the above-mentioned excellent properties, and a molded article thereby.

[0012]

Means for Solving the Problems As a result of repeated studies by the present inventors in order to achieve the above object, a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof and a diol mainly composed of ethylene glycol. In producing a polyester using the components, when a specific hydroxydicarboxylic acid component having a benzene nucleus is used in a specific ratio, it has a high melt viscosity, excellent melt moldability as described above, and transparency, It has been found that a copolyester having excellent heat resistance can be obtained. Furthermore, the copolyester is a dicarboxylic acid component described above,
By carrying out an esterification reaction or a transesterification reaction using a diol component and a hydroxydicarboxylic acid component, melt-polycondensing the reaction product obtained thereby to form a polyester prepolymer, and solid-phase polymerizing the prepolymer. However, they have found that they can be manufactured with high productivity in a short time.

The present inventors have further studied in detail the physical properties and moldability of the above-mentioned copolyester having a high melt viscosity developed by the present inventors. It has a low viscosity at shear rate and a high viscosity at low shear rate and exhibits non-Newtonian properties. Therefore, it is suitable for various kinds of melt molding, especially extrusion blow molding, and used for melt molding, especially extrusion blow molding. In that case, drawdown of the extruded parison does not occur, blow moldability is good, and a molded product having the target shape and dimensions can be manufactured smoothly with high accuracy and high productivity, and a molded product obtained thereby Is
Since it has been found that various properties such as transparency, mechanical properties, and heat resistance are excellent, the present inventors have completed the present invention based on these various findings.

That is, the present invention is mainly composed of a diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit, and has the following general formula (I):

Embedded image Wherein, X is the formula: -CH ₂ CH ₂ - or formula: -CH (C
H ₃ ) CH ₂ —, and n represents an integer of 1 to 7. ] It is a copolymerized polyester containing 0.01 to 1 mol% of the hydroxydicarboxylic acid unit represented by the above, based on the total number of moles of all dicarboxylic acid units and the hydroxydicarboxylic acid unit. And the present invention is a molded product, especially an extrusion blow molded product, comprising the above-mentioned copolymerized polyester. Furthermore, the present invention is a method for producing a molded article by performing extrusion blow molding using the above-mentioned copolymerized polyester. Then, the present invention provides (1) a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof; (2) a diol component mainly composed of ethylene glycol; and (3) the following general formula (II).

[Chemical 4] Wherein, X is the formula: -CH ₂ CH ₂ - or formula: -CH (C
H ₃ ) CH ₂ —, and n represents an integer of 1 to 7. ] The reaction raw material mainly composed of a hydroxydicarboxylic acid component represented by the formula (1) containing a total dicarboxylic acid component and a proportion of 0.01 to 1 mol% based on the total number of moles of the hydroxydicarboxylic acid; After the reaction or transesterification reaction,
It is a method for producing a polyester prepolymer by melt polycondensation, and solid-phase polymerizing the polyester prepolymer to produce the above-mentioned copolyester.

The present invention described above will be described in detail.
As described above, the copolyester of the present invention is a copolyester mainly composed of a diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit. It is necessary to have the hydroxydicarboxylic acid unit represented by the above general formula (I) together with the unit.

In the general formula (I), the group X has the formula: --CH ₂
A group represented by CH ₂ — (ethylene group) or a formula: —CH
A group represented by (1,2-propylene _{group) - (CH 3) CH 2} . In the copolyester of the present invention, in the hydroxydicarboxylic acid unit (I) contained therein,
Even if all of the groups X are ethylene groups or all of the groups X are 1,2-propylene groups, some of the groups X are ethylene groups and the remaining groups X are 1,2-propylene groups. It may be. Among them, it is preferable that the group X in the hydroxydicarboxylic acid unit (I) in the copolyester is an ethylene group, from the viewpoint of ease of production of the copolyester and production cost.

In the copolymerized polyester of the present invention, n in the general formula (I) is an integer of 1-7. Among them, n is preferably 1 or 2, and more preferably 1 from the viewpoints that the thermal stability of the copolyester upon melting is good, and the copolyester is easy to manufacture and the manufacturing cost is high. More preferable.

In the copolyester of the present invention, the production cost of the copolyester, easiness of production,
From the viewpoint of the melt stability of the resulting copolyester, it is particularly preferable that the hydroxydicarboxylic acid unit represented by the general formula (I) is any of the groups represented by the following formulas (III) to (V). Preferably, the hydroxydicarboxylic acid unit represented by the general formula (I) has the following formula (III) or (I
More preferably, it is a group represented by V).

Embedded image

In the copolyester of the present invention, the hydroxydicarboxylic acid is based on the total number of moles of all the dicarboxylic acid units and the hydroxydicarboxylic acid unit represented by the general formula (I) constituting the copolyester. It is necessary to contain the unit in an amount of 0.01 to 1 mol%. When the content of the hydroxydicarboxylic acid unit represented by the general formula (I) is less than 0.01 mol%, the moldability during melt molding such as extrusion blow molding becomes poor, and the parison is particularly used when extrusion blow molding is performed. Drawdown becomes severe and the parison is clogged, and it becomes impossible to manufacture a hollow molded article having a good shape. Moreover, the content of the hydroxydicarboxylic acid unit represented by the general formula (I) is 0.01 mol%
If it is less than the above range, the solid phase polymerization rate at the time of producing the copolyester becomes slow, and the productivity of the copolyester decreases. On the other hand, when the content of the hydroxydicarboxylic acid unit represented by the general formula (I) exceeds 1 mol%, the cross-linking structure in the copolyester becomes too much, and a gel derived from the cross-linking structure is produced. When produced, troubles such as generation of spots and whitening occur and the appearance is impaired. If the degree of polymerization of the copolyester is lowered so as not to cause gelation, the entanglement between the molecules is reduced, and sufficient mechanical strength cannot be obtained. In addition, if the content of the hydroxydicarboxylic acid unit represented by the general formula (I) exceeds 1 mol%, the crystallization rate will be too high during the production of the molded product, and spherulites will be formed to form the molded product. In addition, whitening occurs, the transparency is lowered, and the shape is likely to be poor. In extrusion blow molding, crystallization of parison causes poor blow moldability.

It is possible to obtain a molded product having a sufficiently high melt viscosity, good melt moldability such as extrusion blow molding, smooth prevention of whitening and defective shaping of the molded product, and excellent mechanical strength. From the viewpoint that the copolymerized polyester itself can be produced with high productivity, the hydroxydicarboxylic acid unit represented by the general formula (I) is calculated based on the total number of moles of all dicarboxylic acid units and the hydroxydicarboxylic acid units. It is particularly preferable that the content of is within the range of 0.03 to 0.7 mol%.

The copolymerized polyester of the present invention contains, in addition to the above-mentioned terephthalic acid unit, ethylene glycol unit and hydroxydicarboxylic acid unit represented by the general formula (I),
Based on the total structural units, if 10 mol% or less,
A structural unit derived from another bifunctional compound may be contained if necessary. Structural units derived from such other bifunctional compounds include isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid,
Aromatic dicarboxylic acids such as sodium sulfoisophthalate or ester-forming derivatives thereof; Aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid or ester-forming derivatives thereof; decalin dicarboxylic acid, cyclohexanedicarboxylic acid An alicyclic dicarboxylic acid such as an acid or an ester-forming derivative thereof; further, a hydroxycarboxylic acid such as glycolic acid, hydroxyacrylic acid, hydroxypropionic acid, asiatic acid, quinobaic acid, hydroxybenzoic acid, mandelic acid, or matrolactic acid, or Ester-forming derivatives thereof; aliphatic lactones such as ε-caprolactone; trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, polyethylene glycol Aliphatic diols such Lumpur; hydroquinone, catechol, naphthalene diol, resorcin, bisphenol A, ethylene oxide adduct of bisphenol A, bisphenol S, bisphenol S
Aromatic diols such as ethylene oxide adducts, and structural units derived from bifunctional compounds such as alicyclic diols such as cyclohexanedimethanol. In addition, the copolymerized polyester of the present invention, if necessary, may be a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid, or tricarballylic acid, or its ester-forming property as long as it is 0.1 mol% or less. It may contain a structural unit derived from a polyfunctional compound such as a derivative or a polyhydric alcohol such as trimethylolpropane or pentaerythritol.

The intrinsic viscosity of the copolyester of the present invention may vary depending on the type of melt-molding method of the copolyester, but when it is used in melt molding accompanied by melt extrusion, particularly extrusion blow molding, it has a viscosity of 0.6. It is preferably within the range of from 1.5 to 1.5 dl / g, and particularly from the viewpoint of mechanical strength, appearance, productivity during production of the molded article, etc., of the obtained extrusion blow-molded article, 0.9 to 1.4 dl / g. Is more preferably within the range. In particular, in the case of extrusion blow molding, if the intrinsic viscosity of the copolyester is less than 0.6 dl / g, the drawdown of the parison becomes large during extrusion blow molding, and molding failure tends to occur. Mechanical strength tends to decrease. On the other hand, molding with melt extrusion,
In particular, when extrusion blow molding is performed, if the intrinsic viscosity of the copolyester is higher than 1.5 dl / g, the melt viscosity becomes too high, and a weld line is formed on the molded product during melt extrusion, especially during extrusion blow molding. Further, the appearance of the obtained molded product is liable to be deteriorated, and further, the torque is increased during the extrusion, so that the extrusion amount is apt to be non-uniform, which causes a problem in molding. Further, when the intrinsic viscosity of the copolyester is larger than 1.5 dl / g, the time required to extrude a predetermined amount of the copolyester becomes long and the productivity of the molded product tends to be lowered. The above-mentioned relationship between the intrinsic viscosity of the copolymerized polyester and the moldability of the copolymerized polyester and the physical properties of the molded product obtained from the copolymerized polyester is particularly remarkable in extrusion blow molding, but not limited to extrusion blow molding, extrusion molding, There is almost the same tendency in melt molding involving melt extrusion such as injection / extrusion blow molding.

Further, the copolyester of the present invention is 2
The melt viscosity (η ₁ ) at a shear rate of 0.1 rad / sec at a temperature of 70 ° C. is preferably 5 × 10 ^{4 to} 5 × 10 ⁶ poises. When the melt viscosity (η ₁ ) of the copolyester satisfies the above conditions, curl back is particularly unlikely to occur during melt molding such as extrusion blow molding, and molding defects are hardly generated. It can be completely prevented, and melt fracture and melt swell during melt extrusion.
The phenomenon of 1) is remarkably suppressed, and a molded product having particularly excellent appearance and uniformity can be obtained.

Further, the copolyester of the present invention is 2
Is preferably the melt viscosity at a shear rate of 100 rad / sec (eta ₂₎ is ⁵ × 10 ³ ~5 × 10 5 poise at a temperature of 70 ° C., the melt viscosity of the copolymerized polyester (eta ₂₎ is the condition If it is satisfied, when performing melt molding such as extrusion blow molding, deformation such as drawdown or sagging of the extruded product in the softened state such as parison can be smoothly prevented, and the productivity is improved. It is possible to smoothly prevent thermal decomposition of the copolyester, unevenness of extrusion during extrusion, generation of weld lines, and the like.

The copolymerized polyester of the present invention is
Shear rate 0.1 rad at the temperature of 270 ° C.
/ With the requirements of the requirements and 270 ° C. the melt viscosity at a shear rate of 100 rad / sec at a temperature of the melt viscosity (η ₁₎ (η ₂₎ in seconds, the melt viscosity (eta ₁₎ and melt viscosity (eta ₂₎ is It is more preferable that the following mathematical expression is satisfied: −0.7 ≦ (1/3) log ₁₀ (η ₂ / η ₁ ) ≦ −0.2. When the above formula is satisfied, the copolyester exhibits moderate non-Newtonian properties and exhibits an appropriately low melt viscosity at a high shear rate and an appropriately high melt viscosity at a low shear rate. Therefore, especially when extrusion blow molding or injection / extrusion blow molding is performed, the formability of the parison becomes extremely good. From the viewpoint of improving the parison forming property, (1/3) in the above formula
The value of log ₁₀ (η ₂ / η ₁ ) is −0.60 to −0.25.
Is more preferably within the range. In the above formula, (1/3) log ₁₀ (η ₂ / η ₁ ) is the melt viscosity (η ₁ ) and the melt viscosity in a natural logarithmic graph with the melt viscosity as the vertical axis and the shear rate as the horizontal axis. It is obtained as the slope of the straight line connecting the two points of viscosity (η ₂ ).

The copolymerized polyester of the present invention preferably has a glass transition temperature of 60 ° C. or higher, and from the viewpoint of preventing shrinkage of a molded product obtained by extrusion blow molding or other melt molding, it is a glass. Transition temperature is 70 ℃
The above is more preferable. When the glass transition temperature of the copolyester is less than 60 ° C., after the molded product, especially the extrusion blow molded product, is taken out of the mold, the molded product shrinks due to the relaxation of residual stress and impairs the appearance of the molded product. Sometimes.

Further, the copolyester of the present invention is
270 ° C from the viewpoints of moldability during melt molding such as extrusion blow molding, uniformity of the obtained molded product, and productivity during molding
Melt flow rate (hereinafter sometimes abbreviated as "MFR") at a temperature of 0.3 to 7.5 g / 10 minutes, preferably 0.5 to 5 g / 10 minutes. Is more preferable.

The above-mentioned copolyester of the present invention is
As described above, (1) a dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof; (2) a diol component mainly composed of ethylene glycol; and (3) the following general formula (II)

[Chemical 6] Wherein, X is the formula: -CH ₂ CH ₂ - or formula: -CH (C
H ₃ ) CH ₂ —, and n represents an integer of 1 to 7. ] The reaction raw material mainly composed of a hydroxydicarboxylic acid component represented by the formula (1) containing a total dicarboxylic acid component and a proportion of 0.01 to 1 mol% based on the total number of moles of the hydroxydicarboxylic acid; After the reaction or transesterification reaction,
By melt-polycondensing it to form a polyester prepolymer, and by solid-phase polymerizing the polyester prepolymer, it can be produced in a short time with good productivity.

Then, by carrying out the above-mentioned series of reactions, the above-mentioned general formula (II) is added to the copolymerized polyester.
The hydroxydicarboxylic acid unit represented by the general formula (I) is formed from the hydroxydicarboxylic acid component represented by. Therefore, in the above general formula (II) relating to the hydroxydicarboxylic acid component, the type and content of the group X,
Preferred types of groups, further, detailed contents of n, preferred numerical values thereof, and the like are described with respect to the groups X and n in the above-mentioned description of the hydroxydicarboxylic acid unit represented by the general formula (I) in the copolyester of the present invention. As described in detail, preferred specific examples of the hydroxydicarboxylic acid component represented by the general formula (II) include 5- (2-hydroxyethoxy) -1,3-benzenedicarboxylic acid and 5- [2- (2-Hydroxyethoxy) ethoxy] -1,3-benzenedicarboxylic acid, 5-
(2-hydroxypropoxy) -1,3-benzenedicarboxylic acid, 5- [2- (2-hydroxypropoxy) propoxy] -1,3-benzenedicarboxylic acid, 4- (2
-Hydroxyethoxy) -1,3-benzenedicarboxylic acid, 4- [2- (2-hydroxyethoxy) ethoxy]
-1,3-benzenedicarboxylic acid, 4- (2-hydroxypropoxy) -1,3-benzenedicarboxylic acid, 4-
[2- (2-hydroxypropoxy) propoxy]-
1,3-benzenedicarboxylic acid, 3- (2-hydroxyethoxy) -1,2-benzenedicarboxylic acid, 3- [2
-(2-Hydroxyethoxy) ethoxy] -1,2-benzenedicarboxylic acid, 3- (2-hydroxypropoxy) -1,2-benzenedicarboxylic acid, 3- [2- (2
-Hydroxypropoxy) propoxy] -1,2-benzenedicarboxylic acid, 4- (2-hydroxyethoxy)-
1,2-benzenedicarboxylic acid, 4- [2- (2-hydroxyethoxy) ethoxy] -1,2-benzenedicarboxylic acid, 4- (2-hydroxypropoxy) -1,2-
Benzenedicarboxylic acid, 4- [2- (2-hydroxypropoxy) propoxy] -1,2-benzenedicarboxylic acid, 3- (2-hydroxyethoxy) -1,4-benzenedicarboxylic acid, 3- [2- (2 -Hydroxyethoxy) ethoxy] -1,4-benzenedicarboxylic acid, 3-
Examples thereof include (2-hydroxypropoxy) -1,4-benzenedicarboxylic acid and 3- [2- (2-hydroxypropoxy) propoxy] -1,4-benzenedicarboxylic acid. Among them, 5- (2-hydroxyethoxy) is used as the hydroxydicarboxylic acid represented by the general formula (II) from the viewpoints of production cost of the copolyester, easiness of production, and melt stability of the obtained copolyester. -1,3-benzenedicarboxylic acid, 4- (2-
Hydroxyethoxy) -1,3-benzenedicarboxylic acid and 5- (2-hydroxypropoxy) -1,3-benzenedicarboxylic acid are preferably used, and 5- (2-hydroxyethoxy) -1,3-benzenedicarboxylic acid ,
More preferably, 4- (2-hydroxyethoxy) -1,3-benzenedicarboxylic acid is used.

In the production of the copolyester of the present invention, in addition to the above-mentioned terephthalic acid component, ethylene glycol, and hydroxydicarboxylic acid component represented by the general formula (I), 10 mol% or less based on the total reaction components. If so, as described above for other copolymerized units that may be contained in the copolymerized polyester of the present invention, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid. , Aromatic dicarboxylic acids such as diphenylketone dicarboxylic acid and sodium sulfoisophthalate or ester-forming derivatives thereof; aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid and sebacic acid or ester-forming derivatives thereof; Decalin dicarb Alicyclic dicarboxylic acids such as acid and cyclohexanedicarboxylic acid or ester-forming derivatives thereof; further glycolic acid, hydroxyacrylic acid,
Hydroxycarboxylic acids such as hydroxypropionic acid, asiatic acid, quinobaic acid, hydroxybenzoic acid, mandelic acid, and matrolactic acid, or ester-forming derivatives thereof; aliphatic lactones such as ε-caprolactone; trimethylene glycol, tetramethylene glycol, hexa Aliphatic diols such as methylene glycol, neopentyl glycol, diethylene glycol, polyethylene glycol; hydroquinone, catechol, naphthalene diol, resorcin, bisphenol A, bisphenol A
Aromatic diols such as ethylene oxide adducts of bisphenol S, bisphenol S and ethylene oxide adducts of bisphenol S; and bifunctional compounds such as alicyclic diols such as cyclohexanedimethanol may be used in combination as necessary. Further, if it is 0.1 mol% or less based on all the reaction components, for example, polyvalent carboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid, and tricarballylic acid or its ester-forming derivative, trimethylolpropane ,
If necessary, a polyfunctional compound such as a polyhydric alcohol such as pentaerythritol may be used in combination.

In producing the copolyester, as described above, the dicarboxylic acid component mainly containing terephthalic acid or its ester-forming derivative and the hydroxydicarboxylic acid component represented by the general formula (II) are used. , A diol component mainly composed of ethylene glycol is subjected to an esterification reaction or a transesterification reaction to form a low polymer. In that case, the molar ratio of (total diol component) :( total dicarboxylic acid component) is 1.1: 1 to 1.5: 1, and the molar ratio of [hydroxydicarboxylic acid component represented by general formula (II)]: [total dicarboxylic acid component] is 0.01: 100 to 1: 100. Then, the reaction components may be mixed to carry out an esterification reaction or a transesterification reaction.

The above-mentioned esterification reaction or transesterification reaction is usually about 3 kg / cm ² under normal pressure or absolute pressure.
It is advisable to carry out under the following pressure at a temperature of 230 to 280 ° C. while distilling the produced water or alcohol. Then, subsequently, additives such as a polycondensation catalyst and a coloring inhibitor are added if necessary, and a polyester prepolymer having a desired viscosity is obtained at a temperature of 200 to 280 ° C. under a reduced pressure of 5 mmHg or less. Melt polycondensation is carried out until the polyester prepolymer is formed. In that case, the intrinsic viscosity of the polyester prepolymer is 0.40 to 0.8 from the viewpoint of handling of the polyester prepolymer.
It is preferably in the range of 0 dl / g and its MF
R is preferably 15.0 g / 10 minutes or more.

When a polycondensation catalyst is used in the above-mentioned melt polycondensation reaction, those commonly used in the production of polyesters can be used. For example, antimony compounds such as antimony oxide; germanium such as germanium oxide. Compounds; titanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium; di-n-butyltin dilaurate, di-n-butyltin oxide, dibutyltin diacetate. And the like, and these catalyst compounds may be used alone or in combination of two or more kinds. When using a polycondensation catalyst, the amount is preferably in the range of 0.002 to 0.8 wt% based on the weight of the dicarboxylic acid component.

When a coloring inhibitor is used, for example, phosphorous acid, phosphoric acid, trimethylphosphite, triphenylphosphite, tridecylphosphite, trimethylphosphate, tridecylphosphate, triphenylphosphate. And the like, and these phosphorus compounds may be used alone or in combination of two or more kinds. When using the above-mentioned anti-coloring agent composed of a phosphorus compound, it is preferably in the range of 0.001 to 0.5% by weight based on the weight of the dicarboxylic acid component. Further, in order to suppress coloring due to thermal decomposition of the copolyester, a manganese compound of 0.001 to 0.5% by weight, more preferably 0.05 to 0.3% by weight, based on the weight of the dicarboxylic acid component, For example, manganese acetate or the like is preferably added.

Further, the above-mentioned esterification reaction, transesterification reaction and / or melt polycondensation reaction is carried out by the addition of a tetraalkylammonium hydroxide such as tetraethylammonium hydroxide; a secondary ethylenediamine glycol comprising an organic amine such as triethanolamine or triethylamine. It is preferably carried out in the presence of a biodetergent.

Next, the polyester prepolymer obtained by the above-mentioned melt polycondensation reaction is formed into chips or pellets having an arbitrary shape such as a die shape, a column shape, etc.
After pre-drying at a temperature of 90 ° C or lower, its intrinsic viscosity, M
Solid phase polymerization is carried out until FR or the like reaches a desired value to form the desired copolyester. Solid state polymerization
It is preferably performed under vacuum, reduced pressure, or in an inert gas such as nitrogen gas. Further, it is preferable to carry out the solid phase polymerization while flowing the chips and pellets by an appropriate method such as a tumbling method or a gas fluidized bed method so that the chips and pellets of the polyester prepolymer do not stick to each other. The solid phase polymerization is usually preferably carried out at a temperature within the range of 180 to 240 ° C, more preferably at a temperature within the range of 210 to 240 ° C. Further, the solid-phase polymerization temperature is within the above-mentioned range from the viewpoint of preventing sticking between chips and pellets, and the copolyester intended for production (copolymer polyester finally obtained). The temperature is 15 ° C or more lower than the melting point of), preferably 20 ° C or more lower. From the viewpoint of productivity, it is preferable that the polymerization time is usually in the range of about 5 to 40 hours. Then, by performing the series of reactions described above, the copolyester of the present invention can be produced with good productivity in a short time.

The hydroxydicarboxylic acid represented by the general formula (II) used in the production of the copolyester of the present invention includes 5-hydroxy-1,3-benzenedicarboxylic acid and 4-hydroxy-1,3-benzenedicarboxylic acid. acid,
3-hydroxy-1,2-benzenedicarboxylic acid, 4-
It can be produced by adding alkylene oxides such as ethylene oxide and propylene oxide to hydroxybenzene dicarboxylic acids such as hydroxy-1,2-benzenedicarboxylic acid and 2-hydroxy-1,4-benzenedicarboxylic acid.

Since the copolyester of the present invention is excellent in melt moldability, transparency, heat resistance, mechanical properties, etc., it is extrusion blow molding method, injection / extrusion blow molding method, extrusion molding method, injection molding method. It can be molded into various molded products by other melt molding methods. Among them, the copolyester of the present invention is suitable for use in molding involving a melt extrusion process, and particularly suitable for use in extrusion blow molding. And, melt molding using the copolymerized polyester of the present invention, especially extrusion blow molding with melt extrusion,
When injection / extrusion blow molding, extrusion molding, injection molding, etc. are performed, it is possible to manufacture with good productivity without causing deformation after extrusion, and the molded product obtained by that is dimensional accuracy , Excellent in various properties such as transparency, heat resistance, moisture resistance, and chemical resistance. In particular, when extrusion blow molding is carried out using the copolymerized polyester of the present invention, the drawdown property of the extruded parison is good, and the drawdown time of the parison is kept in an appropriate range. The diameter is uniform, blow moldability is good,
Hollow molded products with good shape and dimensional accuracy without distortion or deformation can be smoothly produced with good productivity without causing problems during molding, and the extrusion blow molded products obtained thereby are transparent. It also has excellent properties such as heat resistance, moisture resistance, and chemical resistance.

In carrying out melt molding using the copolymerized polyester of the present invention, each melt molding method conventionally known for thermoplastic resins, for example, extrusion blow molding method, injection / extrusion blow molding method, It may be carried out according to the extrusion molding method and the injection molding method, and the specific molding contents are not particularly limited. In particular, when performing extrusion blow molding using the copolymerized polyester of the present invention, the type of the extrusion blow molding method is not particularly limited, and like the conventionally known extrusion blow molding method, for example, the copolymerized polyester of the present invention. Melt extrusion molding to form a cylindrical parison, insert this into the blow mold while the parison is in the softened state, blow a gas such as air to blow the parison into a predetermined shape along the shape of the mold cavity. It can be performed by a method of expanding into a hollow shape. When the extrusion blow molding is performed by the above-described method, the melt extrusion temperature is set to a temperature within the range of (melting point of copolyester + 10 ° C.) to (melting point of copolyester + 70 ° C.). It is preferable in terms of

The shape and structure of the molded product of the present invention are not particularly limited, and may be, for example, a hollow molded product, a tubular body, a plate, a sheet, a film, a rod-shaped product, or a molded product, depending on the intended use. Can have any shape and structure, and its dimensions are not limited. Of which
The invention is particularly suitable for hollow molded articles by extrusion blow molding.

Further, the molded article obtained from the copolyester of the present invention is a laminate with other materials such as other plastics, metals, fibers and cloths, even if it is formed of the copolyester of the present invention alone. Or a molded article having a shape other than the laminated structure of the copolymerized polyester of the present invention and the above-mentioned other materials, and is not limited at all. In particular, when the molded article of the present invention is an extrusion blow molded article, for example, a single-layer hollow molded article consisting only of the copolymerized polyester of the present invention (such as a hollow container), the copolymerized polyester of the present invention and polyethylene, polypropylene,
It can be a multi-layer hollow molded article with other plastics such as ethylene-vinyl alcohol copolymer and polyethylene terephthalate (PET). More specifically, for example, it can be composed of PET layer / copolymerized polyester layer / PET layer. Layer bottle, PET layer / Copolyester layer / PET
A five-layer bottle composed of layers / copolyester layer / PET layer may be mentioned. However, the molded article of the present invention is of course not limited to the above.

If desired, the copolyester of the present invention may contain various additives conventionally used for other thermoplastic resins and polyester resins, for example, colorants such as dyes and pigments. , Stabilizers such as UV absorbers,
You may mix | blend an antistatic agent, a flame retardant, a flame retardant auxiliary agent, a lubricant, a plasticizer, an inorganic filler, etc.

[0043]

EXAMPLES The present invention will be specifically described below with reference to Examples and the like, but the present invention is not limited thereto. In the following examples, the content of each structural unit of the polyester (copolymerized polyester or homopolymerized polyester) and the physical properties of the polyester were measured, and the drawdown property and blow moldability of the parison during extrusion blow molding of the polyester were evaluated. The transparency of the molded product (bottle) obtained by blow molding was evaluated as follows.

(1) Content of each structural unit in polyester: The polyester is subjected to methanolysis, the constituent components are separated by high performance liquid chromatography, and the obtained components are quantitatively analyzed by infrared absorption spectrum (IR). The content rate of each structural unit was obtained. In addition, ¹ H of polyester using deuterated trifluoroacetic acid as a solvent
-Confirmed by NMR spectrum.

(2) Intrinsic viscosity of polyester: 30 ° C. in a mixed solvent of equal weight of phenol and tetrachloroethane
Then, the Uderode viscometer ("HRK-3" manufactured by Hayashi Seisakusho)
Mold ”).

(3) Melt Flow Rate (MFR) of Prepolymer and Polyester: Melt Indexer L
244 (manufactured by Takara Industry Co., Ltd.). Specifically, prepolymer or polyester (final product)
The chips of (1) were filled in a cylinder having an inner diameter of 9.55 mm and a length of 162 mm, melted at 270 ° C., and weighted to 2160 with respect to the melted prepolymer or polyester.
g, evenly loaded with a 9.48 mm diameter plunger, and the outflow rate (g / 10 min) of the prepolymer or polyester extruded from the 2.1 mm diameter orifice provided in the center of the cylinder was measured. Was defined as melt flow rate.

(4) Melt viscosity (η ₁ and η ₂ ) of polyester: Shear rate 0 at a temperature of 270 ° C. of polyester using a parallel plate by a mechanical spectrometer (“RMS-800” manufactured by Rheometrics). Melt viscosity (η ₁ ) (poise) at 0.1 rad / sec and melt viscosity (η ₂ ) (poise) of polyester at a shear rate of 100 rad / sec at a temperature of 270 ° C. were dynamically measured.

(5) Polyester glass transition temperature (T
g) and melting point (Tm): according to JIS K7121, by a differential thermal analysis method (DSC) using a thermal analysis system "METTLER TA3000" (manufactured by METTLER CORPORATION),
The measurement was performed under the condition that the temperature rising rate was 10 ° C./min.

(6) Drawdown property of the parison during extrusion blow molding: (i) Drawdown time of the parison (seconds): Extrusion blow molding machine manufactured by Suzuki Iron Works Co., Ltd. (hollow molding machine [TB-
ST-6P type machine]) to form a cylindrical parison by extruding from an annular orifice at an extrusion temperature of 270 ° C., and cutting and forming a bottom portion by sandwiching the cylindrical parison with a blow mold while the cylindrical parison is in a softened state. And blow molding it into a bottle for soft drink (set volume: 1000 ml,
Set wall thickness: 0.4 mm) was manufactured. The extrusion blow molding device used here is designed such that when the parison draws down 25 cm, it is sandwiched by the mold and blown. Therefore, the time (second) required to draw down 25 cm is reduced. Measured as time. In the case of the extrusion blow molding apparatus used here, the moldability is good when the drawdown time is in the range of 10 to 25 seconds, and the moldability is better when it is in the range of 15 to 25 seconds. It will be good. If the drawdown time is less than 10 seconds, the drawdown is severe and the parison shape becomes non-uniform, resulting in defective products with large thickness unevenness after blowing, inability to insert into the blow mold, blockage in the hollow part of the parison, etc. Occurs. Also, the drawdown time is 25
If it exceeds seconds, the productivity of molded products (bottles) will decrease,
Further, since the melt viscosity of the polyester is too high, it is impossible to uniformly blow the polyester, and further, non-adhesion at the pinch-off portion of the bottle, occurrence of a weld line, and breakage of the molding device due to an increase in torque are likely to occur.

(Ii) Difference between maximum diameter (outer diameter) and minimum diameter (inner diameter) of parison: Cylindrical parison was extruded at an extrusion temperature of 270 ° C. using the above extrusion blow molding device, and the parison reached 25 cm. At the time point, the maximum diameter (outer diameter) and the minimum diameter (inner diameter) of the parison were measured, and the difference between them was obtained. The diameter of the annular die of the extrusion nozzle of the above extrusion blow molding apparatus used here is 3.5 cm, but the extruded parison is a drawdown due to its own weight, and the diameter tends to become smaller as the distance from the die increases. If the difference between the maximum diameter and the minimum diameter of the parison is 1 cm or less, normal extrusion blow molding can be performed smoothly. On the other hand, if the difference between the maximum diameter and the minimum diameter of the parison exceeds 1 cm,
Thickness unevenness occurs after blowing, resulting in defective products, and in a more remarkable case, the parison is blocked and it becomes impossible to blow.

(Iii) Comprehensive evaluation of drawdown property of the parison: Table 1 below shows the drawdown time of the parison, the difference between the maximum diameter and the minimum diameter of the parison, and the size of the bottle productivity. The drawdown property was comprehensively evaluated according to the evaluation criteria. At that time, with respect to the productivity of the bottles, the productivity was determined to be good when 120 or more bottles could be produced per hour from the viewpoint of cost and the number of molding defects was less than 10 out of 100 bottles. In addition, molding failure here means bottle shape due to impossibility of insertion into the blow mold due to drawdown of the extruded parison, blockage in the hollow part of the parison, non-adhesion of pinch-off part due to high viscosity and non-uniform blow. When at least one of the problems of deformation and destruction of occurs.

[0052]

[Table 1]

(7) Blow moldability during extrusion blow molding: (i) Average wall thickness of bottle: The bottle body obtained by molding is divided into 10 parts at equal intervals from the upper part to the lower part, and each of them is The wall thickness was measured at 40 points in total by dividing the wall into four at equal intervals in the circumferential direction, and the average wall thickness was calculated. The average wall thickness is from the viewpoint of appearance, touch and bottle strength.
It is preferably in the range of 0.25 mm or more and 0.55 mm or less. (Ii) Bottle thickness unevenness: The difference (mm) between the maximum thickness and the minimum thickness in the wall thickness of the bottle body obtained in the above measurement (i) was obtained and evaluated. The thickness unevenness is preferably less than 0.15 mm, and if the thickness unevenness is more than 0.15 mm, an extremely thin portion and / or a damaged portion is generated, and the appearance and / or the touch is deteriorated. (Iii) Comprehensive evaluation of blow moldability: Comprehensive evaluation of blow moldability was performed according to the evaluation criteria shown in Table 2 below.

[0054]

[Table 2]

(8) Bottle transparency: (i) Haze value (cloudiness value): The body of the bottle was divided into 6 parts over the upper part, the middle part and the lower part, and further divided into 4 parts on the circumference. According to
The haze value at each location was measured using a Poic integrating sphere type light transmittance / total light reflectance meter ("SEP-HS-30D-R type" manufactured by Japan Precision Optics Co., Ltd.), and the average value was taken for the bottle. Haze value (cloudiness value) of. Haze value is 8
If it exceeds, transparency will be poor due to whitening due to spherulite formation or light scattering due to gel-like particles. It is preferable that the haze value is 4 or less from the viewpoint of transparency. (Ii) b value: The bottle body was cut into 1 cm ² (1 cm × 1 cm square pieces) and measured by a reflection method using a color difference meter (“SM-4 type” manufactured by Suga Test Instruments Co., Ltd.). . When the b value exceeds 8, the yellow color of the bottle becomes strong and the appearance becomes poor. The b value is preferably 4 or less in terms of color tone. (Iii) Comprehensive evaluation of transparency of bottles: Comprehensive evaluation of transparency of bottles was performed according to the evaluation criteria shown in Table 3 below.

[0056]

[Table 3]

Example 1 (1) 100.00 parts by weight of terephthalic acid, 44.86 parts by weight of ethylene glycol, and the following formula (VI)

[Chemical 7] 5- (2-hydroxyethoxy) -1,3-represented by
Benzene dicarboxylic acid (hereinafter referred to as "5HEB") 0.
A slurry consisting of 068 parts by weight was prepared, and a slurry of 0.
020 parts by weight germanium dioxide, 0.015 parts by weight phosphorous acid and 0.015 parts by weight tetraethylammonium hydroxide were added. This slurry was heated under pressure (absolute pressure 2.5 kg / cm ² ) to a temperature of 250 ° C., and an esterification reaction was carried out until the esterification rate reached 95% to produce a low polymer. Subsequently, the low polymer was melt-polycondensed at a temperature of 270 ° C. under a reduced pressure of 1 mmHg to produce a prepolymer of a copolyester having an intrinsic viscosity of 0.70 dl / g, which was formed into a strand form from a nozzle. Extruded and cut into cylindrical chips (diameter 2.5 m
m, length 3.5 mm). 27 of this prepolymer
The melt flow rate at 0 ° C. was 32 g / 10 minutes. Then, the chips of the prepolymer of the copolyester obtained above were pre-dried at 150 ° C. for 5 hours, and then under reduced pressure of 0.1 mmHg at 225 ° C.
Solid phase polymerization was carried out for 37 hours at a lower temperature of 7 ° C. to obtain a copolyester having a high molecular weight.

(2) When the content of each structural unit of the copolyester obtained in (1) above was measured by the above method, the terephthalic acid unit, ethylene glycol unit, 5HEB unit and diethylene glycol unit in the copolyester were measured. The content rate of was as shown in Table 5 below. (3) Further, the physical properties of the copolyester obtained in (1) above were measured by the above-mentioned methods.
As shown in, the intrinsic viscosity is 1.25 dl / g, 270 ° C.
MFR at a temperature of 0.5 g / 10 min, melt viscosity at a shear rate of 0.1 rad / sec (η ₁ ) at the same temperature of 4.30 × 10 ⁵ poise, melt viscosity at a shear rate of 100 rad / sec (η 1 ₂ ) is 6.79 × 10 ⁴ poise, and therefore the value of (1/3) log ₁₀ (η ₂ / η ₁ ) is −0.
27. Furthermore, when the Tg and Tm of the copolymerized polyester obtained in (1) above were measured by the above-mentioned method, they were 78 ° C. and 252 ° C., respectively, as shown in Table 5 below.

(4) The copolymerized polyester obtained in (1) above is extruded by the above-mentioned method using an extrusion blow molding device (a hollow molding machine "TB-ST-6P type" manufactured by Suzuki Iron Works Ltd.). Blow molding and bottle (set volume:
1000 ml, set wall thickness: 0.4 mm) was produced, and the drawdown property of the parison at that time, blow moldability, and the transparency of the obtained bottle were measured or evaluated by the methods described above, and the results are shown in Table 10 below. The results shown were obtained.

Examples 2 to 8 Examples except that the amount of ethylene glycol used, the type and amount of hydroxydicarboxylic acid component, and the temperature and time of solid phase polymerization were changed as shown in Tables 5 to 7 below. In the same manner as in 1, the esterification reaction, the melt polycondensation reaction and the solid phase polymerization are performed to produce a copolyester, and the content of each structural unit in the obtained copolyester
When the physical properties of the copolymerized polyester were examined in the same manner as in Example 1, the results were as shown in Tables 5 to 7 below. Further, extrusion blow molding was carried out in the same manner as in Example 1 using the copolymerized polyesters obtained in Examples 2 to 8 to produce bottles, and the drawdown property of the parison, blow moldability and When the transparency of the obtained bottle was measured or evaluated by the above method, it was as shown in Table 10 below.

Comparative Examples 1 to 6 (1) The same as Example 1 except that the types and amounts of raw material components, and the temperature and time of solid phase polymerization were changed as shown in Tables 8 and 9 below. The esterification reaction,
Melt polycondensation reaction and solid phase polymerization were carried out to produce a copolyester, and the content of each structural unit in the obtained copolyester and the physical properties of the copolyester were examined in the same manner as in Example 1, The results are shown in Tables 8 and 9 below. In Comparative Example 5, since the melting point of the obtained copolyester was low, the MFR of the copolyester and the shear rate of 0.1 ra.
Melt viscosity in d / sec (η ₁ ) and shear rate 100ra
Melt viscosity (η ₂ ) in d / sec was measured at 240 ° C.

(2) Extrusion blow molding was carried out in the same manner as in Example 1 using the copolymerized polyesters or homopolymerized polyesters obtained in Comparative Examples 1 to 6 to produce bottles [however, In Example 5, the melting point of the obtained copolyester was low, and thus extrusion blow molding was carried out at a temperature of 240 ° C.], the drawdown property of the parison at that time, the blow moldability and the transparency of the obtained bottle were confirmed. When measured or evaluated by the above-mentioned method, it was as shown in Table 10 below. When the extrusion blow molding of the above (2) was performed, in Comparative Examples 1 to 4, the parison was whitened due to the formation of spherulites during drawdown, and whitening or breakage of the bottom part was generated during molding into a bottle. However, the bottle could not be uniformly blown, and the resulting bottle had gel-like lumps in the transparent portion of the body, resulting in a markedly poor appearance. Further, in Comparative Example 5, the melting point of the copolymerized polyester obtained by copolymerizing cyclohexanedimethanol (CHDM) was lowered, and low temperature molding (240
However, the drawdown during extrusion blow molding was severe and the moldability was poor. Also,
In Comparative Example 6, the drawdown during extrusion blow molding was severe and the bottle could not be manufactured.

The abbreviations used in Tables 5 to 9 below are as shown in Table 4 below.

[Table 4]

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Embedded image

[0065]

[Table 5]

[0066]

[Table 6]

[0067]

[Table 7]

[0068]

[Table 8]

[0069]

[Table 9]

[0070]

[Table 10]

[0071]

EFFECT OF THE INVENTION The copolyester of the present invention has good moldability by extrusion blow molding method, injection / extrusion blow molding method, extrusion molding method, injection molding method, and other melt molding methods.
It can be molded into various molded products, and molded products excellent in various characteristics such as dimensional accuracy, transparency, heat resistance, moisture resistance, and chemical resistance can be manufactured smoothly with good productivity.
Further, the copolymerized polyester of the present invention has high melt viscosity and melt viscosity characteristics suitable for the melt molding method involving the melt extrusion step among the above-mentioned melt molding methods, particularly the extrusion blow molding method. Therefore, when extrusion blow molding is performed using the copolymerized polyester of the present invention, the drawdown property of the extruded parison is good, and the drawdown time of the parison is maintained in an appropriate range. To produce a hollow molded product with a uniform diameter, good blow moldability, no distortion or deformation, good shape and dimensional accuracy, without any trouble during molding, and with good productivity. The resulting extrusion blow-molded product is transparent, heat resistant, moisture resistant,
Has excellent properties such as chemical resistance. Further, the copolyester of the present invention having the above-mentioned characteristics has a length of 2
It can also be suitably used for the production of large hollow moldings via a relatively long parison of 0 cm or more. Further, according to the method for producing a copolyester of the present invention, the copolyester having the above-mentioned excellent properties can be produced in a short time with good productivity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsujifumi Kashiwamura, 1st 2045 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd.

Claims (7)

[Claims] 1. A diol unit mainly composed of an ethylene glycol unit and a dicarboxylic acid unit mainly composed of a terephthalic acid unit, which is represented by the following general formula (I): Wherein, X is the formula: -CH ₂ CH ₂ - or formula: -CH (C
H ₃ ) CH ₂ —, and n represents an integer of 1 to 7. ] The copolyester which contains 0.01-1 mol% of the hydroxydicarboxylic acid unit shown by these based on the total number of moles of all dicarboxylic acid units and this hydroxydicarboxylic acid unit. 2. The copolyester according to claim 1, which has an intrinsic viscosity of 0.6 to 1.5 dl / g. 3. A shear rate of 0.1 at a temperature of 270 ° C.
Melt viscosity (η ₁ ) in rad / sec is 5 × 10 ^{4 to} 5 × 10
⁶ poise and a shear rate of 10 at a temperature of 270 ° C
Melt viscosity (η ₂ ) at 0 rad / sec is 5 × 10 ^{3 to} 5 × 1.
0 is ⁵ poises and the melt viscosity (eta ₁₎ and Equation melt viscosity (eta ₂₎ is the following; a _{-0.7 ≦ (1/3) log 10 (} η 2 / η 1) ≦ -0.2 The copolyester according to claim 1 or 2, which is satisfied. 4. A molded article made of the copolymerized polyester according to claim 1. 5. The molded product according to claim 4, which is an extrusion blow molded product. 6. A method for producing a molded article by carrying out extrusion blow molding using the copolymerized polyester according to claim 1. 7. A dicarboxylic acid component mainly composed of terephthalic acid or an ester-forming derivative thereof; (2) a diol component mainly composed of ethylene glycol; and (3) the following general formula (II): ] Wherein, X is the formula: -CH ₂ CH ₂ - or formula: -CH (C
H ₃ ) CH ₂ —, and n represents an integer of 1 to 7. ] The reaction raw material mainly composed of a hydroxydicarboxylic acid component represented by the formula (1) containing a total dicarboxylic acid component and a proportion of 0.01 to 1 mol% based on the total number of moles of the hydroxydicarboxylic acid; After the reaction or transesterification reaction,
4. The method for producing a copolyester according to claim 1, wherein the polyester prepolymer is melt-polycondensed to form a polyester prepolymer, and the polyester prepolymer is solid-phase polymerized.