JPH09136945A - Copolyester and molding thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolyester which has a high melt viscosity, a low viscosity at a high shear rate, and a high viscosity at a low shear rate, is free from the creation of melt fracture and a gelled product during melt molding, exhibits a low crystallization rate and, when melt-molded by extrusion blow molding, can provide, with good moldability, a molding possessing excellent dimensional accuracy, transparency, appearance, handle, mechanical properties, heat resistance and other properties. SOLUTION: This copolyester is composed mainly of a terephthalic acid unit and an ethylene glycol unit and further comprises at least one member selected from among a dicarboxylic acid unit, a diol unit, and a hydroxycarboxylic acid unit, in an amt., based on the total number of moles of the whole constituent unit of the copolyester, of 1 to 4mol% for an alicyclic or aliph. difunctional compd. unit, 0.005 to 1mol% for a polyfunctional compd. unit, and, for a monofunctional compd. unit, a value satisfying the formula: 20×(n-2)×b}>=c>= 0.1×(n-2)×b} (wherein (b) represents mol% of the polyfunctional compd. unit, (c) represents mol% of the monofunctional compd. unit, and (n) represents the average functionality of a polyfunctional compd. for deriving the polyfunctional compd. unit.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a copolymerized polyester, a method for producing the same, a method for producing a molded article using the copolymerized polyester, and a molded article obtained by the method. More specifically, the present invention has a high melt viscosity, yet exhibits a non-Newtonian property that is a low viscosity at a high shear rate and a high viscosity at a low shear rate, and causes melt fracture such as sharkskin flow during molding. The present invention relates to a copolyester having an excellent property that a crystallization rate is suppressed and a gelled product is not produced, a method for producing the same, and a molded article formed by the copolyester. When a molded product is manufactured by molding or other melt molding, a high-quality molded product with excellent transparency, appearance, touch, and mechanical properties, heat resistance, moisture resistance, chemical resistance, etc. The copolymerized polyester of the present invention is particularly suitable for use in 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. As it is less worrying about chemicals and is superior in hygiene and safety, juices, soft drinks,
In recent years, it has been widely used as a hollow container for filling seasonings, oils, cosmetics, detergents, and 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.

Among the above-mentioned molding methods, the former extrusion blow molding method has a simpler process than the latter injection blow molding method, and does not require a high level of technology for manufacturing and molding a mold. In addition, equipment costs and mold manufacturing costs are low, making it suitable for high-mix low-volume production. In addition, the extrusion blow molding method has an advantage that a molded article having a complicated shape having a small object, a deep object, a large object, a handle, and the like can be produced.

[0005] From this point, various attempts have 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 low melt viscosities. For this reason, when extrusion blow molding is performed, it is difficult for the parison after extrusion to significantly draw down and shape. In addition, there is a problem that crystallization is apt to occur at the time of blowing after extrusion, transparency is impaired, and shaping failure occurs. And, the above-mentioned inconveniences caused by such low melt viscosity and easy crystallization in a general-purpose polyester resin such as polyethylene terephthalate are 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 having a uniform shape and dimensions and excellent transparency, particularly a large hollow molded product, by extrusion blow molding using a general-purpose polyester resin such as polyethylene terephthalate. is there.

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

Therefore, various proposals have been made so far regarding a polyester resin suitable for extrusion blow molding,
As such a conventional technique, when a dicarboxylic acid or its ester forming component is reacted with a diol component to produce a polyester, a diol component containing a bisphenol A ethylene oxide adduct is used for extrusion blow molding. Method for producing polymerized polyester (JP-A-5-065338); Copolymerized polyester using cyclohexanedimethanol as a diol component when a polyester is produced by reacting a dicarboxylic acid or its ester forming component with a diol component (For example, a comparative example of the above-mentioned JP-A-5-065338, JP-A-7-2070)
No. 03, etc.); A method for producing a branched polyester using terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol and a small amount of a polyfunctional branching compound (US Defense No. T954,005); General-purpose polyfunctional compounds such as trimethylolpropane, pentaerythritol, and trimellitic acid, along with dicarboxylic acid components such as and ester-forming derivatives thereof and diol components such as ethylene glycol.
And a method for producing a copolyester for extrusion blow molding using a chain terminating agent such as benzoic acid and stearic acid (JP-A-54-137095); dicarboxylic acid components such as terephthalic acid and its ester-forming derivatives After reacting a diol component such as ethylene glycol with esterification reaction or transesterification reaction to produce a low polymer, a cross-link consisting of general-purpose polyfunctional compounds such as trimethylolpropane, pentaerythritol and trimellitic acid A method of reacting an agent to carry out a polycondensation reaction to form a prepolymer, and solid-phase polymerizing the prepolymer to produce a copolyester for extrusion blow molding (JP-A-54-163962).
JP-A-55-92730); A method for producing a copolyester for extrusion blow molding using a branching agent such as terephthalic acid, isophthalic acid, pentaerythritol and an end capping agent such as m-anisic acid (special feature). JP-A-61-181823); and the like are known.

In the case of the above-mentioned and conventional methods, the melting point of the copolyester is lowered by the copolymerization of the bisphenol A ethylene oxide adduct and cyclohexanedimethanol, whereby the melt extrusion temperature is set to a lower temperature than before. Therefore, the melt viscosity during extrusion blow molding can be increased.
However, even in that case, the melt viscosity is not high enough to perform extrusion blow molding, so that a significant drawdown occurs in the parison after extrusion, making it difficult to shape, and making extrusion blow molding smooth. Can't do it. Further, as an adverse effect of molding at a low temperature, an extrusion blow molded product such as a bottle has minute surface roughness, and the appearance and feel of the molded product are easily impaired. In addition, the copolymerized polyester obtained by the above and the conventional methods often cannot perform solid-state polymerization due to a low melting point, and even when solid-state polymerization can be performed, the solid-state polymerization rate is extremely slow. Since the degree of polymerization is not sufficiently increased, an increase in melt viscosity is difficult to achieve, and a molded article obtained from the copolymerized polyester has disadvantages such as poor transparency and large thickness unevenness.

Further, in the above-mentioned conventional method, 1,4-cyclohexanedimethanol is used in an amount of 10 relative to all diol units.
Since it is copolymerized at a high proportion of ˜40 mol%, low temperature molding is possible by amorphization or lowering of melting point like the conventional method, and by the branched structure by the polyfunctional branching agent compound, the conventional method and The melt viscosity of the polyester tends to be higher than that of the obtained copolyester. However, the conventional method does not mention solid-state polymerization at all. And, the copolyester obtained by the conventional method is a so-called "amorphous" polymer, or even if it is crystalline, its melting point is too low, so that solid phase polymerization is impossible, or solid phase polymerization is carried out. However, when the solid phase polymerization is carried out, the melting point is too low to cause sticking between chips or pellets, or the polymerization rate is too low, so that the molecular weight cannot be sufficiently increased. Therefore, the melt viscosity of the copolyester obtained there is not high enough to perform extrusion blow molding, and as a result, the drawdown of the parison after extrusion occurs and shaping becomes difficult, and extrusion blow molding is performed smoothly. I can't. Further, also in the conventional method, as in the above-mentioned and the prior arts, as an adverse effect of molding at a low temperature, minute surface roughness is generated in an extrusion blow-molded product such as a bottle, and the appearance and feel of the molded product are easily impaired. Moreover, if the copolyester is dried at a high temperature before molding, it will have to be dried at a low temperature because sticking between chips and pellets will occur, so it is necessary to dry for a long time with a large-scale drying device such as a vacuum drying facility. Yes, productivity is reduced. Further, in the case of an amorphous polymer, sticking between chips and pellets is likely to occur in the lower portion of the hopper of the extruder, which causes a problem that extrusion cannot be performed.

Further, the copolyester obtained by the above-mentioned conventional method in which a crosslinking agent composed of a polyfunctional compound and a chain-terminating agent such as benzoic acid or stearic acid are used in combination is superior to an ethylene terephthalate homopolymer or the like. Although the melt viscosity and melt strength are increased, the crystallization rate is higher than that of the ethylene terephthalate homopolymer, so that spherulites are generated during the extrusion of the parison, and the resulting extruded blow-molded product is significantly whitened. , It lacks transparency. Also, when a large hollow molded product is manufactured by extrusion blow molding by extruding a long parison of 20 cm or more, the lower part of the parison solidifies due to crystallization, and the pinch-off part at the bottom of the container such as a bottle has poor adhesion. Becomes Moreover, as in the cases of the above-mentioned conventional methods, minute surface roughness occurs on the molded product, and the appearance and feel of the molded product are likely to be remarkably poor. Further, in terms of the productivity of the copolyester, since the crystallinity rapidly increases during solid phase polymerization, the diffusion of ethylene glycol in the polymer necessary to increase the polymerization rate is hindered, It is difficult to smoothly produce the desired copolyester. Further, since the copolymerized polyester obtained by the conventional method has an unusually high degree of crystallinity, unmelted particles frequently occur in an extrusion step in extrusion blow molding, and it is difficult to produce a good molded product. The above-mentioned various drawbacks are particularly prominent when the resin extrusion speed is high, such as when a large hollow molded product is manufactured.

Further, the copolyester obtained by the above-mentioned conventional method has a higher crystallization rate than the ethylene terephthalate homopolymer, like the copolyester obtained by the above-mentioned conventional method, and therefore the parison is extruded. Occasionally, spherulites are formed, and the resulting extrusion blow-molded product is remarkably whitened and lacks transparency. Further, in the production of a large hollow molded product accompanied by the extrusion of a long parison of 20 cm or more, the lower part of the parison is solidified by crystallization, and the pinch-off portion at the bottom of the hollow molded product such as a bottle causes poor adhesion. . Furthermore, since the degree of crosslinking of the copolyester cannot be controlled properly by not using the end-capping agent composed of a monofunctional compound, a gelled substance derived from the crosslinked structure is generated because of the overcrosslinked state. As a result, spots such as spots appear on the molded product and the appearance of the molded product is impaired. Further, also in the case of this conventional method, as in the case of the above-mentioned conventional methods, minute surface roughness occurs in the molded product, and the appearance and touch of the molded product tend to be remarkably poor. And, in the above-mentioned JP-A-54-163962 and JP-A-55-92730 mentioned above as the prior art, it is described that a small amount of isophthalic acid, neopentyl glycol or the like can be copolymerized. In that case, although the crystallization rate of the copolyester is suppressed and the solidification of the bottom part of the parison and the whitening of the hollow molded article during the production of the hollow molded article are reduced to some extent, they are derived from the overcrosslinked structure. The generation of gel-like substances and the surface roughness of the molded products are still unsolved.

Further, in the above-mentioned conventional method, the melt viscosity and the shear sensitivity of the melt viscosity are improved by copolymerizing a branching agent such as pentaerythritol and an end capping agent such as m-anisic acid, and further performing solid phase polymerization. It is said that a copolyester having a high cost and a small amount of gel derived from a crosslinked structure can be obtained. Furthermore, by copolymerizing isophthalic acid as a bifunctional component, the crystallization rate of the copolyester is suppressed and a hollow molded article is obtained. Solidification at the bottom of the parison during production and whitening of the hollow molded article tend to be reduced to some extent. However, using conventional copolyesters,
When manufacturing a large-sized hollow molded product accompanied by a long parison extrusion of 0 cm or more, there is a drawback that the bottom of the previously extruded parison is crystallized and the bottom of the hollow molded product is whitened. Also in the case of this conventional method, as in the case of the above-mentioned conventional methods, minute surface roughness is generated in the molded product, and its appearance and touch are likely to be remarkably poor. In particular, when the extrusion amount per unit time is 20 kg or more, such as when manufacturing a large hollow molded product accompanied by extrusion of a long parison of 20 cm or more, minute surface roughness of the molded product becomes remarkable. In addition, unmelted seeds are likely to occur in the molded product due to difficulty in melting the crystal.

Moreover, none of the copolymerized polyesters obtained by the above-mentioned conventional methods and the molded articles obtained from them have sufficiently high mechanical properties such as drop impact strength. In the case of a hollow molded article such as a bottle, the drop impact height is usually required to be 1 m or more, but the present inventors have extruded the copolymerized polyester obtained by the above-mentioned conventional methods. When the bottles were manufactured by blow molding, the drop impact strength of each of them was less than 1 m, which caused a problem in practical use. In particular, a bottle having an internal volume of 1 liter or more has a large breaking energy and is easily broken. The bottle obtained from the conventional copolyester is inferior in drop impact strength, and it is speculated that this is because the mechanical properties of the copolyester are lowered due to the copolymerization of isophthalic acid. Further, the present inventors have tried to produce polyethylene terephthalate having a high degree of polymerization by solid phase polymerization, in addition to the above-mentioned conventional techniques.
It was found that polyethylene terephthalate, which has an extremely slow solid phase polymerization rate and a sufficiently high degree of polymerization and melt viscosity suitable for extrusion blow molding, cannot be efficiently obtained in a short time, and is not practical in terms of productivity. .

[0014]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned various problems, and (1) Extrude when it is used for extrusion blow molding because the melt viscosity is sufficiently high. The parison is not drawn down and can be smoothly shaped into a hollow molded product; (2) The crystallization speed is slow, and spherulites are not formed during the extrusion of the parison, and the resulting extrusion blow molded product is molded. (3) In the production of a large hollow molded product that extrudes a parison with a length of 20 cm or more, solidification does not occur due to crystallization of the lower part of the parison, and molding of bottles, etc. does not occur. Adhesion failure at the pinch-off part at the bottom of the product does not occur; (4) Microscopic surface roughness does not occur, and various molded products with excellent appearance and feel can be obtained; (5) Gel-like product derived from an overcrosslinked structure From In addition, the molded product does not have spots such as spots, is excellent in transparency, and has a good appearance. (6) The resulting molded product has excellent impact resistance; 7) It has various characteristics such as high solid-state polymerization rate and excellent productivity; it has excellent melt moldability, especially extrusion blow moldability, has the desired shape and dimensions, and has an appearance and a touch. Another object of the present invention is to provide a polyester capable of smoothly producing a high-quality molded product having excellent transparency and the like with high accuracy. It is an object of the present invention to provide a method capable of producing a polyester having the above-mentioned various excellent properties in a short time with high productivity. Further, the object of the present invention is to
It is an object of the present invention to provide a method for producing a molded product by performing melt molding, particularly extrusion blow molding, using a polyester having the above-mentioned excellent properties, and a molded product by the method.

[0015]

As a result of repeated studies by the present inventors to achieve the above object, in a polyester mainly composed of terephthalic acid units and ethylene glycol units, terephthalic acid units and An alicyclic or aliphatic dicarboxylic acid unit other than an ethylene glycol unit, at least one alicyclic or aliphatic bifunctional compound unit selected from a diol unit and a hydroxycarboxylic acid unit is contained in a specific ratio, and When a unit composed of a trifunctional or higher polyfunctional compound and a unit of a monofunctional compound derived from a monofunctional compound are contained in specific proportions, respectively, the resulting copolyester has a low viscosity and a low viscosity at a high shear rate. It exhibits high viscosity, non-Newtonian properties at shear rates, and therefore its copolymerization It is possible to smoothly perform various melt-molding using, has particularly good moldability suitable for use in extrusion blow molding, melt viscosity is sufficiently high, drawdown of the extruded parison occurs. However, it was found that the hollow molded article can be smoothly shaped.

Moreover, the above-mentioned copolyesters developed by the present inventors have a slow crystallization rate, and do not form spherulites during extrusion of the parison during extrusion blow molding.
The obtained extrusion blow-molded product has no whitening and is excellent in transparency. Further, when a large hollow molded product accompanied by extrusion of a long parison of 20 cm or more is produced, solidification occurs due to crystallization of the lower part of the parison. It was also found that the pinch-off portion at the bottom of the molded product such as a bottle did not cause defective adhesion. Further, the above-mentioned copolyesters developed by the present inventors exhibit an appropriate melt shear stress at the time of melt molding, and therefore a molded product obtained by the melt molding has a good appearance and a touch without surface roughness. Furthermore, they have found that the degree of crosslinking is well controlled, no gel is formed due to overcrosslinking, the transparency is excellent, and the mechanical strength is excellent. The present inventors have also found that the copolyester has a high solid phase polymerization rate and can be economically produced with good productivity, and completed the present invention based on these various findings.

That is, the present invention provides (1) a copolyester mainly composed of a terephthalic acid unit and an ethylene glycol unit and having another copolymer unit; (2) the above-mentioned copolymer polyester is another copolymer unit. As the polymerized unit, (i) at least one alicyclic or aliphatic bifunctional unit selected from alicyclic or aliphatic dicarboxylic acid units other than terephthalic acid units and ethylene glycol units, diol units and hydroxycarboxylic acid units The compound unit (a) has a proportion of 1 to 4 mol% based on the total number of moles of all constituent units of the copolyester; (ii) a carboxyl group, a hydroxyl group and / or their ester-forming groups. The polyfunctional compound unit (b) derived from at least one kind of polyfunctional compound having 3 or more of Having a proportion of 0.005-1 mol% based on the total number of moles of all constituent units of the ester; and (iii) at least one monofunctional monocarboxylic acid, monoalcohol and their ester-forming derivatives. The monofunctional compound unit (c) derived from the compound is represented by the following formula (I) based on the total number of moles of all the constituent units of the copolyester.

[0018]

## EQU00004 ## {20.times. (N-2) .times.b} .gtoreq.c.gtoreq. {0.1.times. (N-2) .times.b} (I) [wherein b = polyfunctional compound unit (b ) Ratio (mol%) c = monofunctional compound unit (c) in the copolyester
(Mole%) n = average number of functional groups of polyfunctional compound that induces polyfunctional compound unit (b)].

Further, 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.

The present invention is a method for producing a copolyester mainly comprising terephthalic acid units and ethylene glycol units and having other copolymerization units; (1) comprising terephthalic acid or an ester-forming derivative thereof. It is mainly composed of a dicarboxylic acid component and a diol component composed of ethylene glycol, and in addition to the above-mentioned main dicarboxylic acid component and diol component, (a)
At least one alicyclic or aliphatic bifunctional compound selected from alicyclic or aliphatic dicarboxylic acids, hydroxycarboxylic acids, their ester-forming derivatives and alicyclic or aliphatic diols other than ethylene glycol (B) at least one polyfunctional compound having three or more carboxyl groups, hydroxyl groups and / or their ester-forming groups; and (c) at least monocarboxylic acid, monoalcohol and their ester-forming derivatives. A reaction raw material containing one of the above-mentioned alicyclic or aliphatic 2
The content of the functional compound is such that the ratio of the alicyclic or aliphatic bifunctional compound unit (a) derived from the alicyclic or aliphatic bifunctional compound is the total number of moles of all constituent units of the copolyester. The content of the polyfunctional compound in the reaction raw material is such that the proportion of the polyfunctional compound unit (b) derived from the polyfunctional compound is in the range of 1 to 4 mol%. The amount of the monofunctional compound in the reaction raw material is 0.005 to 1 mol% based on the total number of moles of all the constituent units of the copolyester; The ratio of the derived monofunctional compound unit (c) is based on the total number of moles of all the constituent units of the copolyester, the following formula (I);

[0021]

## EQU00005 ## {20.times. (N-2) .times.b} .gtoreq.c.gtoreq. {0.1.times. (N-2) .times.b} (I) [wherein, b = polyfunctional compound unit in copolymerized polyester (b ) Ratio (mol%) c = monofunctional compound unit (c) in the copolyester
Ratio (mol%) n = the average number of functional groups of the polyfunctional compound for deriving the polyfunctional compound unit (b)], the reaction raw material is subjected to an esterification reaction or a transesterification reaction. And then melt-polycondensate it to form a polyester prepolymer; and (2) solid-phase polymerize the polyester prepolymer obtained in step (1) above; Is a manufacturing method.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail. As described above, the copolymerized polyester of the present invention needs to be a copolymerized polyester mainly composed of terephthalic acid units and ethylene glycol units and having other copolymerized units. In the copolymerized polyester of the present invention, the total ratio (mol%) of the terephthalic acid unit and the ethylene glycol unit is calculated from the total number of moles of all the constituent units constituting the copolymerized polyester (that is, 100 mol%), and the alicyclic group described below is used. It is a value obtained by subtracting the ratio of the formula or aliphatic bifunctional compound unit (a), the polyfunctional compound unit (b) and the monofunctional compound unit (c). Generally, the total proportion (mol%) of the terephthalic acid unit and the ethylene glycol unit in the copolyester of the present invention is about 70 to 98 mol% with respect to the total number of moles of all structural units constituting the copolyester. Preferably about 90
More preferably, it is about 98 mol%. If the total proportion of terephthalic acid units and ethylene glycol units in the copolyester is less than 70 mol%, the copolyester becomes amorphous and it becomes difficult to achieve a high degree of polymerization by solid phase polymerization, while 98 mol% When it exceeds the above range, the crystals of the copolyester become difficult to melt, and unmelted spots are likely to occur in the molded product.

The copolymerized polyester of the present invention is
In addition to the terephthalic acid unit and the ethylene glycol unit, it is selected from alicyclic or aliphatic dicarboxylic acid units, alicyclic or aliphatic diol units other than ethylene glycol units, and alicyclic or aliphatic hydroxycarboxylic acid units. It has at least one alicyclic or aliphatic bifunctional compound unit (a) in a proportion of 1 to 4 mol% based on the total number of moles of all constituent units of the copolyester.

In the present invention, the bifunctional compound unit (a) needs to be a unit derived from an alicyclic or aliphatic compound as described above, and the bifunctional compound unit (a) is required.
Is an alicyclic or non-aliphatic dicarboxylic acid unit such as an isophthalic acid unit or a hydroxybenzoic acid unit, a diol unit or a hydroxycarboxylic acid unit, a microscopic surface roughness on an extrusion blow-molded article such as a bottle. And the appearance and feel of the molded product are significantly impaired. In particular, the surface roughness becomes remarkable in the production of molded products such as large bottles having an extrusion rate of 20 kg / hour or more, and the impact resistance of the molded products is also poor.

The alicyclic or aliphatic bifunctional compound unit (a) is an alicyclic or aliphatic dicarboxylic acid unit other than a terephthalic acid unit and an ethylene glycol unit, a diol unit and a hydroxycarboxylic acid unit. Although it may be any, preferred examples of the alicyclic or aliphatic bifunctional compound unit (a) include malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid and other aliphatic dicarboxylic acids; decalin dicarboxylic acid, Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; ester-forming derivatives thereof; fats such as 1,3-propanediol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, 2-butyl-2-ethyl-propanediol Group diols; cycloaliphatic such as cyclohexanedimethanol Ol; glycolic acid, hydroxy acrylic acid, and hydroxycarboxylic hydroxycarboxylic acid (lactone acid) such as propionic acid or structural units derived from ester-forming derivatives thereof. The copolyester of the present invention may have, as the alicyclic or aliphatic bifunctional compound unit (a), only one kind of the above structural units or two or more kinds thereof. Good.

In the copolymerized polyester of the present invention, the alicyclic or aliphatic bifunctional compound unit (a)
Is a cyclohexanedimethanol unit and / or a cyclohexanedicarboxylic acid unit, the production of the copolyester becomes easy, and the drop strength of the copolyester and the molded article obtained therefrom can be increased. . Here, the cyclohexanedimethanol unit means at least one diol unit selected from the group consisting of a 1,2-cyclohexanedimethanol unit, a 1,3-cyclohexanedimethanol unit and a 1,4-cyclohexanedimethanol unit. To do. The cyclohexanedicarboxylic acid unit is 1,
It means at least one dicarboxylic acid unit selected from the group consisting of a 2-cyclohexanedicarboxylic acid unit, a 1,3-cyclohexanedicarboxylic acid unit and a 1,4-cyclohexanedicarboxylic acid unit. As the alicyclic or aliphatic bifunctional compound unit (a) in the present invention,
1,4-cyclohexanedimethanol units and // from the viewpoint of easy availability and further increasing the drop strength of the copolyester and the molded articles obtained therefrom.
Alternatively, 1,4-cyclohexanedicarboxylic acid unit is more preferable.

In the copolymerized polyester of the present invention, the ratio of the alicyclic or aliphatic bifunctional compound unit (a) [having two or more alicyclic or aliphatic bifunctional compound units (a) is included. In the case of the above, the total proportion] is 1 to 4 mol% based on the total number of moles of all the constituent units of the copolyester, as described above. If the proportion of the alicyclic or aliphatic bifunctional compound unit (a) is less than 1 mol%, the crystallization rate of the copolyester becomes too fast, and whitening occurs due to the formation of spherulites during melt molding. The transparency of the molded product is lost, and in the production of a large hollow molded product that involves extrusion of a parison with a length of 20 cm or more, the lower part of the parison solidifies early due to crystallization, and molded products such as bottles. The pinch-off part at the bottom of the will cause poor adhesion. In addition, when the degree of crystallinity is too high, unmelted bumps are formed on the molded product when melt molding is performed, resulting in poor appearance.

On the other hand, if the proportion of the alicyclic or aliphatic bifunctional compound unit (a) exceeds 4 mol%, the crystallinity and melting point of the copolyester become too low, and solid phase polymerization may not be performed. , Or even when solid phase polymerization can be carried out, the solid phase polymerization rate becomes extremely slow and the degree of polymerization does not increase sufficiently, resulting in poor mechanical strength of the copolyester and its molded product. It becomes a thing.

The productivity of the copolyester itself can be increased, and the melt viscosity of the copolyester can be sufficiently increased so that melt molding such as extrusion blow molding can be performed more favorably, and there is no whitening. In view of the fact that a molded article having even more excellent transparency and mechanical strength can be obtained, the proportion of the alicyclic or aliphatic bifunctional compound unit (a) in the copolymerized polyester is It is particularly preferably in the range of 2 to 4 mol% based on the total number of moles of all constitutional units of the polymerized polyester.

By the way, a small amount of diethylene glycol unit is contained in the copolymerized polyester produced by by-producting a small amount of diethylene glycol, which is a dimer of the ethylene glycol component, during the production of the copolymerized polyester of the present invention. When the polyester contains a large amount of diethylene glycol units, the glass transition temperature of the copolyester decreases, causing problems such as deterioration of heat resistance and coloring, and heat resistance of molded articles such as bottles obtained from the copolyester. Since the strength and color tone become poor, it is preferable to reduce the proportion of diethylene glycol units in the copolyester as much as possible. For the above-mentioned reason, it is preferable that the proportion of diethylene glycol units in the copolyester is less than 1.5 mol% based on the total number of moles of all constitutional units of the copolyester,
It is more preferable that the content be 1.4 mol% or less, and 1.3 mol% or less.
It is more preferable to keep it to be mol% or less. Further, a polyalkylene glycol unit such as a polyethylene glycol unit causes the same adverse effect on the copolyester as the diethylene glycol unit, so it is preferable that the polyalkylene glycol unit is not included in the copolyester of the present invention. Therefore, 1 to 4 of the above-mentioned alicyclic or aliphatic bifunctional compound unit (a) in the copolyester of the present invention.
The value of mol% means a value not including a diethylene glycol unit or a polyalkylene glycol unit having an ether bond.

Further, the copolyester of the present invention is
Based on the total number of moles of all constituent units of the copolyester, the polyfunctional compound unit (b) having three or more carboxyl groups, hydroxyl groups and / or their ester-forming groups is added to all the constituent units of the copolyester. It is necessary to have a ratio of 0.005 to 1 mol% based on the total number of moles of the above [the total ratio when two or more polyfunctional compound units (b) are present].

The polyfunctional compound unit (b) is a unit derived from a polyfunctional compound having three or more groups selected from the group consisting of a carboxyl group, a hydroxyl group and their ester-forming groups. The polyfunctional compound for deriving the polyfunctional compound unit (b) is not particularly limited as long as it is a polyfunctional compound having only three or more carboxyl groups, and a polyfunctional compound having only three or more hydroxyl groups. It may be a compound or a polyfunctional compound having a total of three or more carboxyl groups and hydroxyl groups.

Preferred examples of the polyfunctional compound unit (b) include trimesic acid, trimellitic acid, 1,2,3-benzenetricarboxylic acid, pyromellitic acid, 1,4,5,5.
Aromatic polycarboxylic acids such as 8-naphthalenetetracarboxylic acid; aliphatic polycarboxylic acids such as 1,3,5-cyclohexanetricarboxylic acid; aromatic polyalcohols such as 1,3,5-trihydroxybenzene; trimethylolpropane , Pentaerythritol, glycerin, 1,
Aliphatic polyalcohols such as 3,5-cyclohexanetriol; aromatics such as 4-hydroxyisophthalic acid, 3-hydroxyisophthalic acid, 2,3-dihydroxybenzoic acid, protocatechuic acid, gallic acid and 2,4-dihydroxyphenylacetic acid Polyhydroxycarboxylic acid; tartaric acid,
Mention may be made of aliphatic polyhydroxycarboxylic acids such as malic acid; polyfunctional compound units derived from their ester-forming derivatives. The copolymerized polyester of the present invention may have, as the polyfunctional compound unit (b), only one type of the above-mentioned polyfunctional compound units or may have two or more types thereof.

Among the above, the copolyester of the present invention is one of structural units derived from trimellitic acid, pyromellitic acid, trimesic acid, trimethylolpropane and pentaerythritol as the polyfunctional compound unit (b). Or, it is preferable to have two or more kinds from the viewpoint of easiness of production of the copolyester and production cost. Furthermore, trimellitic acid and trimesic acid are particularly preferable in that gelation is suppressed.

In the copolyester, the proportion of the polyfunctional compound unit (b) is 0.005 to the above.
When it is out of the range of 1 mol% and is less than 0.005 mol%, the melt viscosity does not become sufficiently high, and the proper melt viscosity,
That is, non-Newtonian property does not occur, and moldability during melt molding such as extrusion blow molding becomes poor. In particular, when extrusion blow molding is performed, the drawdown of the parison becomes severe, and the parison is clogged or crushed, so that a hollow molded article having a good shape cannot be manufactured. Moreover, when the proportion of the polyfunctional compound unit (b) is less than 0.005 mol%, 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 proportion of the polyfunctional compound unit (b) in the copolyester exceeds 1 mol%, the crosslinked structure portion in the copolyester becomes too large and a gel derived from the overcrosslinked structure is produced. However, when a molded product is manufactured, problems such as generation of spots and whitening occur, and the transparency, appearance, and touch are impaired. When the degree of polymerization of the copolyester is lowered so as not to cause gelation, intermolecular entanglement is reduced, and sufficient mechanical strength cannot be obtained. Moreover, the polyfunctional compound unit (b)
If the ratio exceeds 1 mol%, the crystallization rate will be too high during the production of the molded product, and spherulites will be generated to cause whitening of the molded product, resulting in poor transparency and poor shaping. In extrusion blow molding, blow moldability due to crystallization of parison becomes poor.

Since the melt viscosity is sufficiently high, melt molding such as extrusion blow molding can be more favorably performed, whitening and improper shaping of molded products can be smoothly prevented, and mechanical strength is further excellent. From the viewpoint that a molded product can be obtained and the productivity of the copolyester itself can be further enhanced, the proportion of the polyfunctional compound unit (b) is
It is particularly preferably in the range of 0.01 to 0.5 mol% based on the total number of moles of all constituent units of the copolyester.

Further, the copolyester of the present invention comprises a monocarboxylic acid, together with the alicyclic or aliphatic bifunctional compound unit (a) and polyfunctional compound unit (b) described above.
It is necessary to have monofunctional compound units (c) derived from at least one monofunctional compound of monoalcohols and their ester-forming derivatives. In the copolyester of the present invention, the monofunctional compound unit (c)
Functions as a capping compound unit, caps the molecular chain end groups and / or branched chain end groups in the copolyester, and prevents excessive crosslinking and gel formation in the copolyester. The monofunctional compound unit (c) is
It is not particularly limited as long as it is a unit derived from at least one kind of monocarboxylic acid, monoalcohol and their ester-forming derivatives.

Preferred examples of the monofunctional compound unit (c) include benzoic acid, o-methoxybenzoic acid, m-methoxybenzoic acid, p-methoxybenzoic acid, o-methylbenzoic acid, m-methylbenzoic acid, p. -Methylbenzoic acid, 2,3
-Dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,
5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid,
3,4-Dimethylbenzoic acid, 3,5-Dimethylbenzoic acid, 2,4,6-Trimethylbenzoic acid, 2,4,6-Trimethoxybenzoic acid, 3,4,5-Trimethoxybenzoic acid, 1-Naphthoic acid , 2-naphthoic acid, 2-biphenylcarboxylic acid, 1-naphthaleneacetic acid, 2-naphthaleneacetic acid and other aromatic monocarboxylic acids; n-octanoic acid, n-nonanoic acid, myristic acid, pentadecanoic acid, stearic acid, oleic acid , Aliphatic monocarboxylic acids such as linoleic acid and linolenic acid; ester-forming derivatives of the aforementioned monocarboxylic acids; benzyl alcohol, 2,5-dimethylbenzyl alcohol, 2-phenethyl alcohol, phenol, 1-naphthol, 2-naphthol Aromatic monoalcohols such as: pentadecyl alcohol, stearyl alcohol, polyethylene Recall monoalkyl ethers, polypropylene glycol monoalkyl ether,
Polytetramethylene glycol monoalkyl ether,
Mention may be made of units derived from monofunctional compounds such as oleyl alcohol and aliphatic monoalcohols such as cyclododecanol. The copolyester of the present invention may have, as the monofunctional compound unit (c), only one type of the above-mentioned monofunctional compound units, or may have two or more types thereof.

Among them, the copolyester of the present invention is a monofunctional compound unit (c) containing benzoic acid, 2,
It has a unit derived from one or more monofunctional compounds selected from 4,6-trimethoxybenzoic acid, 2-naphthoic acid, stearic acid, stearyl alcohol and polyethylene glycol monoalkyl ether. It is preferable from the viewpoint of ease of production of the copolyester and production cost.

The copolyester of the present invention is
Based on the total number of moles of all constitutional units of the copolyester, the monofunctional compound unit (c) is represented by the following mathematical formula.
(I);

[0042]

## EQU6 ## {20 × (n−2) × b} ≧ c ≧ {0.1 × (n−2) × b} (I) [wherein, b = polyfunctional compound unit (b in copolyester) ) Ratio (mol%) c = monofunctional compound unit (c) in the copolyester
Ratio (mol%) n = the average number of functional groups of the polyfunctional compound that induces the polyfunctional compound unit (b)] [a total ratio of two or more monofunctional compound units (c)] It is necessary to have in.

Here, in the above formula (I), the average number of functional groups n of the polyfunctional compound that induces the polyfunctional compound unit (b) is the total number of polyfunctional compounds used to form the copolyester. Represents the average value of functional groups, for example, n = 3 when only a trifunctional compound is used as a polyfunctional compound, and when a trifunctional compound and a tetrafunctional compound are used as a polyfunctional compound in a molar ratio of 50:50. Is n = 3 × 0.5 +
4 × 0.5 = 3.5, and when a trifunctional compound and a tetrafunctional compound are used as a polyfunctional compound in a molar ratio of 20:80, n = 3 × 0.2 + 4 × 0.8 = 3.8. Become. Therefore, although not limited, for example, the polyfunctional compound unit (b) is a trifunctional unit derived from a trifunctional compound, and the content ratio of the polyfunctional compound unit (b) in the copolyester is 0. In the case of 0.1 mol%, in the above formula (I), n = 3 and b = 0.1 (mol%), so that 2 (mol%) ≧ c ≧ 0.01 (mol%) , Based on the total number of moles of all constituent units of the copolyester, the monofunctional compound unit (c) is 0.01 to
It is necessary to have it at a ratio of 2 mol%.

When the proportion of the monofunctional compound unit (c) in the copolyester is less than the lower limit of the above-mentioned formula (I), that is, {0.1 × (n-2) × b} (mol%). Since a gel is formed due to the over-crosslinked state, problems such as spots and whitening occur when a molded product is manufactured, resulting in a poor appearance and loss of transparency. On the other hand, the proportion of the monofunctional compound unit (c) in the copolymerized polyester is the upper limit value of the above-mentioned mathematical formula (I), that is, {20 × (n−
If it is more than 2) × b} (mol%), the solid phase polymerization rate at the time of producing the copolyester becomes slow, and the productivity of the copolyester decreases. From the viewpoints of the ease and cost of producing the copolyester, the appearance of the resulting molded article, the transparency, etc., the proportion of the monofunctional compound unit (c) in the copolyester is {10 × (n−2).
It is preferable that xb} ≧ c ≧ {0.5 × (n−2) × b}.

As is apparent from the above description, in short, the copolyester of the present invention is a copolymer that satisfies all of the above-mentioned requirements (1) and (2) (i) to (iii) at the same time. Polymerized polyester, that is, all of alicyclic or aliphatic bifunctional compound units (a), polyfunctional compound units (b) and monofunctional compound units (c) which are mainly composed of terephthalic acid units and ethylene glycol units And the proportion of these three units is in the above-mentioned specific range, it is necessary that the copolymerized polyester has the above-mentioned (1) and (2) (i) to (iii). The target copolyester cannot be obtained even if any of the requirements is lacking.

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 in extrusion blow molding, it is 0.8. 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 product, etc. of the obtained extrusion blow-molded product, 0.9 to 1.4 dl / g. Is more preferably within the range. In particular, in the case of extrusion blow molding, when the intrinsic viscosity of the copolyester is less than 0.8 dl / g, drawdown of the parison becomes large at the time of extrusion blow molding, and molding failure easily occurs, and further Mechanical strength tends to decrease. On the other hand, in the case of carrying out molding accompanied by melt extrusion, particularly extrusion blow molding, when the intrinsic viscosity of the copolyester is larger than 1.5 dl / g, the melt viscosity becomes too high, and during melt extrusion, especially extrusion blow molding. Weld lines are likely to occur in the molded product during molding, the appearance of the resulting molded product tends to be poor, and the extrusion amount tends to be non-uniform due to high torque during extrusion. Become. 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 decrease. The above-mentioned relationship between the intrinsic viscosity of the copolyester and the moldability of the copolyester and the physical properties of the molded product obtained from it are
Although it remarkably appears in extrusion blow molding, almost the same tendency occurs not only in extrusion blow molding but also in melt molding involving melt extrusion such as extrusion molding and 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 is possible to obtain a molded product that can be completely prevented, and that the phenomena of melt fracture (die fracture) and die swell during melt extrusion are significantly suppressed, and that the appearance and mechanical properties are particularly excellent. .

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, it is possible to smoothly prevent deformation such as drawdown or sagging of the extruded product in a softened state such as a parison, resulting in high productivity, and It is possible to smoothly prevent the thermal decomposition of the copolyester and the occurrence of extrusion unevenness and weld lines during extrusion.

The copolymerized polyester of the present invention is
Shear rate 0.1 rad / at the temperature of 270 ° C.
Melt viscosity in seconds (η ₁ ) and melt viscosity at a shear rate of 100 rad / s at temperature of 270 ° C. (η ₂ )
And the melt viscosity (η ₁ ) and melt viscosity (η ₂ ) of the following mathematical formula (II);

[0050]

Equation 7] _{-0.7 ≦ (1/3) log 10 (} η 2 / η 1) ≦ -0.2 (II) and even more preferred that satisfies. When the above formula (II) is satisfied, the copolyester exhibits moderate non-Newtonian properties, exhibits a reasonably low melt viscosity at high shear rates, and a reasonably high melt viscosity at low shear rates. 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) lo in the above formula (II) is used.
More preferably, the value of g ₁₀ (η ₂ / η ₁ ) is in the range of −0.60 to −0.25. The above formula (II)
In, (1/3) log ₁₀ (η ₂ / η ₁ ) is the melt viscosity (η ₁ ) and the melt viscosity (η ₂ ) in both natural logarithmic graphs with the melt viscosity as the vertical axis and the shear rate as the horizontal axis. It is calculated as the slope of the straight line connecting the two points. The values of the melt viscosity (η ₁ ) and the melt viscosity (η ₂ ) referred to in the present specification refer to the values measured by the method described in the section of Examples below.

Further, the copolyester of the present invention has 2
Shark skin critical shear stress (σ
ss) is 1 × 10 ⁶ dyne / cm ² or more, and 27
The shear stress (σ100) at a shear rate of 100 rad / sec at a temperature of 0 ° C. is preferably equal to or less than the value of the above-mentioned sharkskin critical shear stress (σss). The present inventors have found that the shear stress of the copolyester at the time of melt molding is also closely related to the above-mentioned surface roughness of the obtained molded product, and it is 270 ° C. of the copolyester.
Sharkskin critical shear stress (σss) at 1 × 10 ⁶
Shear rate 10 at dyne / cm ² or more and 270 ° C
When the shear stress (σ100) at 0 rad / sec is equal to or less than the value of the sharkskin critical shear stress (σss), the phenomenon of surface roughness is significantly suppressed during melt molding such as extrusion blow molding, resulting in transparency. It is possible to obtain a molded article which is particularly excellent in appearance and touch such as. It is presumed that the reason is that, in the case of the copolyester having the shear stress as described above, the remarkable release of the elastic normal stress between the copolyester melt and the extruder die is suppressed. It The sharkskin critical shear stress (σss) of the copolyester and the shear stress (σ100) at a shear rate of 100 rad / sec are the shear stress when extruded in a strand shape by a capillary nozzle using a capillary nozzle. The details are as described in the Examples section below.

Further, 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 article obtained by extrusion blow molding or other melt molding, glass is used. Transition temperature is 70 ℃
More preferably. 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 undergoes shrinkage due to relaxation of residual stress and impairs the appearance of the molded product. Sometimes.

Further, the copolymerized polyester of the present invention has a melt flow at a temperature of 270 ° C. from the viewpoints of moldability at the time of melt molding such as extrusion blow molding, uniformity of the obtained molded product, and productivity at the time of molding. The rate (hereinafter sometimes abbreviated as “MFR”) is preferably in the range of 0.3 to 7.5 g / 10 minutes, and more preferably in the range of 0.5 to 5 g / 10 minutes. preferable.

The copolyester of the present invention preferably has a crystallinity of 20 to 40%. When the crystallinity of the copolyester is less than 20%, pellets or chips are likely to stick to each other during solid phase polymerization, which makes it difficult to carry out solid phase polymerization smoothly, resulting in lower productivity. Moreover, during molding, blocking occurs between pellets and chips of the copolyester, which makes it difficult to perform molding smoothly. On the other hand, if the crystallinity of the copolyester exceeds 40%, the meltability of the pellets and chips becomes poor, and the resin squeaks during the molding (sound is generated due to the friction between the pellets and the chips), and the molding is accompanied by the torque increase. A load is applied to the machine, which makes it difficult to smoothly perform molding, and unmolded lumps are generated in the molded product, which easily causes defects such as transparency, appearance, and touch. In order to smoothly perform solid phase polymerization to enhance the productivity of the copolyester, and to smoothly perform melt molding to obtain a molded product of good quality, the crystallinity of the copolyester is 25 to More preferably, it is in the range of 35%.

Further, the copolymerized polyester of the present invention preferably has a cold crystallization temperature of 150 ° C. or lower and a crystallization heat amount in the cold crystallization of 20 J / g or lower.
When the cold crystallization temperature of the copolyester is higher than 150 ° C, or the heat of crystallization in the cold crystallization is 20 J /
If it exceeds g, the growth rate of the spherulites becomes high and the obtained molded product is liable to be whitened and the transparency tends to deteriorate. Further, when extrusion blow molding is performed, solidification of the parison occurs at an early stage, and shaping tends to be difficult. In order to sufficiently delay the spherulite generation rate during melt molding and obtain a molded article having excellent transparency with good shapeability, the cold crystallization temperature of the copolymerized polyester is 140 ° C or less, and More preferably, the heat of crystallization in crystallization is 15 J / g or less. The cold crystallization temperature and the heat of crystallization in the cold crystallization referred to here are the differential thermal analysis method (DS).
The value is the value measured by C), and the details are as described in the section of Examples below.

As described above, the copolyester of the present invention includes (1) (i) terephthalic acid or its ester-forming derivative; (ii) ethylene glycol; (iii) an alicyclic or aliphatic bifunctional compound. Unit (a)
At least 1 selected from the above-mentioned alicyclic or aliphatic dicarboxylic acids, hydroxycarboxylic acids, ester-forming derivatives thereof and alicyclic or aliphatic diols other than ethylene glycol for introducing the above into a copolyester. An alicyclic or aliphatic bifunctional compound consisting of a seed; (iv) the above-mentioned carboxyl group, hydroxyl group and / or ester forming group thereof for introducing the polyfunctional compound unit (b) into the copolyester. Of at least one polyfunctional compound having 3 or more; and (v) the above-mentioned monocarboxylic acid, monoalcohol and ester-forming derivative thereof for introducing the monofunctional compound unit (c) into the copolyester. A reaction raw material consisting of at least one monofunctional compound; 2 alicyclic or aliphatic said in
The content of the functional compound is such that the proportion of the alicyclic or aliphatic bifunctional compound unit (a) derived from the bifunctional compound is 1 to 4 mol based on the total number of moles of all the constituent units of the copolyester. % So that the content of the polyfunctional compound in the reaction raw material is such that the proportion of the polyfunctional compound unit (b) derived from the polyfunctional compound is all the constituent units of the copolyester. In an amount of 0.005 to 1 mol% based on the total number of moles of the monofunctional compound; and the content of the monofunctional compound in the reaction raw material is a monofunctional compound unit derived from the monofunctional compound. After the reaction raw material is subjected to an esterification reaction or a transesterification reaction, the reaction raw material is in such a proportion that the above formula (I) is satisfied based on the total number of moles of all the constituent units of the copolyester. , So The polyester prepolymer to solid phase polymerization obtained by then (2) the step (1); the melt polycondensation engaged to form a polyester prepolymer by, it can be produced with good productivity in a short time.

In the above-mentioned method for producing a copolyester, the alicyclic or aliphatic bifunctional compound, the polyfunctional compound and the monofunctional compound are used as the alicyclic or aliphatic bifunctional compound in the copolyester. An alicyclic or aliphatic bifunctional compound for introducing the unit (a), a polyfunctional compound for introducing the polyfunctional compound unit (b), and a monofunctional for introducing the monofunctional compound unit (c). As the compound, each of the compounds exemplified above with respect to the copolyester of the present invention can be used.

In producing the copolyester, (total diol component): (total dicarboxylic acid component)
The molar ratio of 1.1: 1 to 1.5: 1,
The molar ratio of (polyfunctional compound component) :( total dicarboxylic acid component) is 0.0001: 1 to 0.02: 1,
Moreover, the molar ratio of (monofunctional compound component) :( polyfunctional compound component) is {0.1 × (n−1)}: 1 to {20 × (n−
1)}: 1 (n is the same as above) and the reaction components are preferably 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 perform the treatment under the following pressure at a temperature of 230 to 300 ° C. while distilling off the produced water or alcohol. Then, subsequently, an additive such as a polycondensation catalyst or a coloring preventing agent is added, if necessary, and then, usually under reduced pressure of 5 mmHg or less, at a temperature of 200 to 300 ° C., a polyester prepolymer having a desired viscosity. Melt polycondensation is carried out until the above is obtained to form a polyester prepolymer. In this case, the intrinsic viscosity of the polyester prepolymer is 0.40 to 0.40 from the viewpoint of handling of the polyester prepolymer.
It is preferably in the range of 0.75 dl / g, and its MFR is preferably 15.0 g / 10 minutes or more.

When the polycondensation catalyst is used in the above-mentioned melt polycondensation reaction, those which are usually used in the production of polyester 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 and tetrabutoxytitanium; di-n-butyltin dilaurate, di-n
Examples include tin compounds such as -butyltin oxide and dibutyltin diacetate, 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 preventing agent is used, for example, phosphorous acid, phosphoric acid, trimethyl phosphite, triphenyl phosphite, tridecyl phosphite, trimethyl phosphate, tridecyl phosphite, triphenyl phosphite. 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, 0.001 to 0.5% by weight, more preferably 0.05 to 0.3% by weight of a cobalt compound, based on the weight of the dicarboxylic acid component, For example, it is preferable to add cobalt acetate or the like.

Further, as described above, when a large amount of diethylene glycol units are contained in the copolyester, the glass transition temperature of the copolyester is lowered, and the heat resistance is lowered and the coloring is caused accordingly. Although the heat resistance, strength, color tone and the like of the molded article such as are poor, the above-mentioned esterification reaction, transesterification reaction and / or melt polycondensation reaction is carried out by tetraalkylammonium hydroxide such as tetraethylammonium hydroxide; It is preferable to carry out the reaction in the presence of a diethylene glycol by-product inhibitor composed of an organic amine such as triethanolamine or triethylamine, because the proportion of diethylene glycol units in the copolyester can be reduced.

Next, the polyester prepolymer obtained by the melt polycondensation reaction described above is formed into chips or pellets of any shape such as a die or a column, which is usually used in 1
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 is
It is preferably performed under vacuum, reduced pressure, or in an inert gas such as nitrogen gas. Further, it is preferable to carry out solid phase polymerization while flowing the chips or pellets by an appropriate method such as a rolling method or a gas fluidized bed method so that the polyester prepolymer chips or pellets do not stick to each other. Solid phase polymerization is usually preferably carried out at a temperature within the range of 180 to 240 ° C.,
It is more preferable to carry out at a temperature in the range of 190 to 230 ° 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, and preferably 20 ° C. or more lower. In addition, the polymerization time for solid phase polymerization is usually about 5-4.
The range of 0 hours is preferable from the viewpoint of productivity.
Then, by performing the above-described series of steps, the copolyester of the present invention can be produced with good productivity in a short time.

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 copolymerized polyester of the present invention is suitable for use in molding involving a melt extrusion step, and particularly suitable for use in extrusion blow molding. And, the melt molding using the copolymerized polyester of the present invention, especially extrusion blow molding involving melt extrusion,
When injection / extrusion blow molding, extrusion molding, etc. are performed, it can be manufactured with good productivity without causing deformation after extrusion, and the molded product obtained by this is
Excellent in various properties such as dimensional accuracy, transparency, mechanical properties, heat resistance, moisture resistance, and chemical resistance. In particular, 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. The diameter is uniform, the blow moldability is good, and there is no trouble at the time of molding, and it is possible to smoothly manufacture a hollow molded product having a good shape and dimensional accuracy without distortion or deformation with good productivity. . And, the molded product such as the extrusion blow molded product obtained thereby,
It is excellent in transparency, appearance, and touch with no generation of spots or whitening, and has no poor adhesion at the bottom during pinch-off, and has various properties such as mechanical properties, heat resistance, moisture resistance, and chemical resistance. Are better.

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 parison into the blowing mold while it is in the softened state, and blow gas such as air to blow the parison into the prescribed shape along 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 method, the melt extrusion temperature is (melting point of copolymerized polyester +10
C.) to (melting point of copolyester + 70 [deg.] C.), preferably (melting point of copolyester + 10 [deg.] C.) to (melting point of copolyester + 40 [deg.] C.).
More preferably, the temperature is within the range.

The shape, structure, etc. 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 body, a molded product or the like, 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 producing hollow molded articles by extrusion blow molding.

Further, a molded article obtained from the copolyester of the present invention is a laminate with other materials such as other plastics, metals, fibers and cloth 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 product of the present invention is an extrusion blow molded product, for example, a single-layer hollow molded product (a hollow container or the like) consisting only of the copolyester of the present invention, the copolyester 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), and more specifically, for example, PET layer / copolymerized polyester layer / PET layer 3
Examples thereof include a layer bottle and a 5-layer bottle composed of PET layer / copolymerized polyester layer / PET layer / copolymerized polyester layer / PET layer. 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,
An antistatic agent, a flame retardant, a flame retardant auxiliary, a lubricant, a plasticizer, an inorganic filler, and the like may be blended.

[0070]

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, and extrusion was performed. The transparency and gel generation rate of the molded product (bottle) obtained by blow molding, and the drop fracture height and the drop strength of the molded product (bottle) were evaluated as follows.

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

(2) Intrinsic viscosity of polyester: 30 ° C. in an equal weight mixed solvent of phenol and tetrachloroethane
Udelode 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)
After filling the above chips into a cylinder having an inner diameter of 9.55 mm and a length of 162 mm and melting at 270 ° C. (however, Comparative Example 8
21 and 21 because the copolyester was amorphous
(Melted at 0 ° C.), the molten prepolymer or polyester was evenly loaded by a plunger having a weight of 2160 g and a diameter of 9.48 mm, and extruded from an orifice having a diameter of 2.1 mm provided in the center of the cylinder. Outflow rate of prepolymer or polyester (g / 10 minutes)
Was measured and this was made into melt flow rate (MFR).

(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 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 (however, in Comparative Examples 8 and 11, the copolymerized polyester was amorphous, so the measurement was performed at 210 ° C.).

(5) Shark Skin Critical Shear Stress (σss) and Shear Stress (σ100) of Polyester: Shear at a temperature of 270 ° C. by using a capillary nozzle having a diameter of 2 mm and a length of 10 mm by a Capillograph (manufactured by Toyo Seiki). The polyester was extruded in strands at varying speeds. The shear stress at the time when the surface of the strand is roughened (at the time when the ten-point average surface roughness becomes 1.5 μmRz or more) is calculated, and the shear stress is calculated as the critical shear stress (σss) (dyne / cm) of shark skin. ² ) Further, using the same apparatus, the shear rate (σ of the polyester at a temperature of 270 ° C. and a shear rate of 100 rad / sec (σ
100) (dyne / cm ² ) was measured (however, Comparative Examples 8 and 11 were 210 because the copolyester was amorphous.
(Measured in ° C).

(6) Crystallinity of polyester (χc):
The density (d) (25 ° C.) of the polyester was measured, and the density (d) of a completely amorphous PET (polyethylene terephthalate) was measured.
The crystallinity (χc) of the polyester was determined from the following mathematical formula (III), where a) was 1.335 and the density (dc) of fully crystallized PET (polyethylene terephthalate) was 1.501.

[0077]

## EQU00008 ## .chi.c (%) = [{dc.times. (D-da)} / {d.times. (Dc-da)}]. Times.100 (III)

(7) Glass transition temperature of polyester (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 of a heating rate of 10 ° C./min.

(8) Cold crystallization temperature (Tcc) of polyester
And cold crystallization calorie (ΔHcc): according to JIS K7121, by differential thermal analysis (DSC) using a thermal analysis system "METTLER TA3000" (manufactured by METTLER CORPORATION),
After the sample was kept at the temperature of Tm + 40 ° C. for 5 minutes, the measurement was performed under the condition of the temperature decreasing rate of 5 ° C./min.

(9) Drawdown property of parison during extrusion blow molding: (i) Drawdown time of parison (seconds): Extrusion blow molding apparatus manufactured by Placo Co., Ltd. (hollow molding machine "BM-3
04.J2 type machine ") at a temperature of 270 [deg.] C. and an extrusion rate of 25 kg / hour to form a cylindrical parison (excluding Comparative Examples 8 and 11 in which the copolyester is amorphous). Since it was molded at an extrusion temperature of 210 ° C), while the cylindrical parison was in the softened state, it was cut and bottom-formed by sandwiching it with a blow molding die, and this was blow molded to cool it with a capacity of 1800 ml and a weight of 80 g. Beverage bottles were manufactured. The above-mentioned extrusion blow molding device used here is designed such that when the parison draws down 35 cm, it is sandwiched between the molds and blows. Therefore, the time (second) required to draw down 35 cm is reduced by drawdown. Measured as time. In the case of the extrusion blow molding device used here, the moldability becomes good when the drawdown time is in the range of 10 to 25 seconds. 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, if the drawdown time exceeds 25 seconds,
Productivity of molded products (bottles) is low, and because the melt viscosity of polyester is too high, it is not possible to blow it evenly. In addition, non-bonding at the pinch-off part of bottles, weld lines, and torque increase Is likely to be damaged.

(Ii) Difference between maximum diameter (outer diameter) and minimum diameter (outer diameter) of parison: A cylindrical parison was extruded at an extrusion temperature of 270 ° C. using the above extrusion blow molding apparatus (however, Comparative Example 8). And 11 were molded at the extrusion temperature of 210 ° C because the copolyester was amorphous), and the parison was 35 cm.
The maximum diameter (outer diameter) and the minimum diameter (outer diameter) of the parison were measured at the time when the temperature reached, and the difference between them was obtained. The diameter of the annular die of the extrusion nozzle of the above-mentioned extrusion blow molding apparatus used is 3.5 cm, but the extruded parison has a drawdown due to its own weight, and the diameter tends to decrease as the parison moves away from the die. When the difference between the maximum diameter and the minimum diameter of the parison is 1 cm or less, extrusion blow molding can usually be performed smoothly. On the other hand, when 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 or, in a more significant case, the parison is blocked and blown becomes impossible.

(Iii) Comprehensive evaluation of drawdown property of parison: Evaluation shown in Table 1 below from the viewpoint of drawdown time of parison, difference between maximum diameter and minimum diameter of parison, and some aspects of bottle productivity. The drawdown property was comprehensively evaluated according to the standard. At that time, regarding the productivity of the bottles, 120 or more bottles could be produced per hour from the viewpoint of cost, and if the molding defects were less than 10 out of 100 bottles, the productivity was considered to be good. The molding failure here means that the extruded parison cannot be inserted into the blow mold due to drawdown, the parison is blocked in the hollow part, the pinch-off part is not adhered due to the high viscosity, and the bottle shape is caused by uneven blow. It means the case where at least one of the troubles of deformation and destruction occurs.

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[Table 1] Comprehensive evaluation criteria for drawdown of parison ◯: When all of the following conditions are satisfied (a) The drawdown time is within the range of 15 seconds or more and 25 seconds or less. (B) The difference between the maximum diameter and the minimum diameter of the parison is 1 cm or less. (C) The amount of bottles produced is 120 or more per hour, and the proportion of poorly formed bottles is less than 10 out of 100 bottles. Δ: When any of the following conditions is satisfied (a) The drawdown time is within a range of 10 seconds or more and less than 15 seconds, or more than 25 seconds and 60 seconds or less. (B) The difference between the maximum diameter and the minimum diameter of the parison is in the range of more than 1 cm and 2 cm or less. (C) The production amount of bottles is 60 or more and less than 120 bottles per hour, and the ratio of defective bottles is 10 or more and less than 30 bottles per 100 bottles. X: When any of the following conditions is met: (a) Drawdown time is less than 10 seconds or more than 60 seconds. (B) The difference between the maximum diameter and the minimum diameter of the parison exceeds 2 cm. (C) The production volume of bottles is less than 60 per hour, and the ratio of defective bottles is 30 or more out of 100 bottles.

(10) Blow moldability during extrusion blow molding: (i) Average wall thickness of bottle: The bottle body obtained by molding was divided into 10 parts at equal intervals from the upper part to the lower part, and each of them was 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.
The range is preferably 0.3 mm or more and 0.7 mm or less. (Ii) Uneven thickness of the bottle: The difference (mm) between the maximum thickness and the minimum thickness in the wall thickness of the bottle body obtained in the above (i) was obtained and evaluated. It is preferable that the thickness unevenness is less than 0.3 mm, and if it is more than 0.3 mm, an extremely thin portion and / or a damaged portion is generated, and the appearance and / or the feel are poor. (Iii) Comprehensive evaluation of blow moldability: Comprehensive evaluation of blow moldability was performed according to the evaluation criteria shown in Table 2 below.

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[Table 2] Comprehensive evaluation standard for blow moldability ◯: The average wall thickness is in the range of 0.3 mm or more and 0.7 mm or less, and the thickness unevenness is less than 0.3 mm. X: The average wall thickness is less than 0.3 mm or more than 0.7 mm, or the thickness unevenness is 0.3 mm or more.

(11) Transparency of bottles: (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. Similarly, 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 Optical Co., Ltd.), and the average value was calculated. The haze value (haze value) of the bottle was taken. When the haze value exceeds 8, the transparency becomes 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” manufactured by Suga Test Instruments Co., Ltd.). . When the b value exceeds 8, the color tone of the bottle becomes yellowish and the appearance becomes poor. It is preferable in terms of color tone that the b value is 4 or less. (Iii) Comprehensive evaluation of bottle transparency: Comprehensive evaluation of bottle transparency was performed according to the evaluation criteria shown in Table 3 below.

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[Table 3] Comprehensive evaluation criteria for bottle transparency ◯: The haze value is 4 or less and the b value is 4 or less. Δ: The haze value is in the range of more than 4 and 8 or less, or the b value is more than 4 and 8 or less. X: The haze value exceeds 8, or the b value exceeds 8.

(12) Bottle gel generation rate: Polyester in the bottle body was cut out in a weight of 1 g and dissolved in 10 ml of hexafluoroisopropanol at a temperature of 30 ° C. for 5 hours to dissolve insoluble gel. It was filtered through a 4G glass filter. After heating the gel at a temperature of 100 ° C. for 60 minutes and drying, the weight was measured, and the weight percentage based on the cut polyester sample (1 g) was determined as the gel product generation rate. The evaluation shown in Table 4 below was obtained. The evaluation of the rate of gelation of the bottle was performed according to the standard.

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[Table 4] Evaluation criteria for bottle gel generation rate ◯: The gel generation rate is 2.5% or less. Δ: Gel generation rate is more than 2.5% and 5% or less. X: Gel generation rate exceeds 5%.

(13) Drop impact strength of bottles: Each of the 10 bottles obtained by molding was filled with water so as not to leave voids and capped. When the bottle is naturally dropped from a height of 50 cm and the bottle is not broken, the drop height is increased by 10 cm and the bottle is naturally dropped in the same manner, and the operation is sequentially repeated to obtain the height at which the bottle is broken. The average value of the heights of the bottles at the time of breaking was taken as the falling breaking height. Further, the drop impact strength of the bottle was evaluated according to the evaluation criteria shown in Table 5 below.

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[Table 5] Evaluation Criteria for Drop Impact Strength of Bottle ⊚: The height at which the bottle drops and breaks is 120 cm or more. ◯: The height at which the bottle drops and breaks is 100 cm or more and less than 120 cm. X: The height at which the bottle drops and breaks is less than 100 cm.

Example 1 (1) 100.00 parts by weight of terephthalic acid, 48.73 parts by weight of ethylene glycol, 4.34 parts by weight of 1,4-cyclohexanedimethanol, and 0.1 part of trimellitic anhydride.
A slurry consisting of 16 parts by weight and 0.104 parts by weight of 2-naphthoic acid was prepared, and a slurry of germanium dioxide 0.1.
020 parts by weight, 0.015 parts by weight of phosphorous acid, 0.015 parts by weight of cobalt acetate and 0.015 parts by weight of 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. Then, 1 mmH
The low polymer was melt-polycondensed at a temperature of 270 ° C. under a reduced pressure of g to produce a prepolymer of a copolyester having an intrinsic viscosity of 0.70 dl / g, which was extruded from a nozzle in a strand form. It was cut into cylindrical chips (diameter about 2.5 mm, length about 3.5 mm). Melt flow rate (MFR) of this prepolymer at 270 ° C
Was 30 g / 10 minutes. (2) Next, after the prepolymer chips of the copolyester obtained above are pre-dried at 150 ° C. for 5 hours, solid phase polymerization is performed at 210 ° C. for 29 hours under a reduced pressure of 0.1 mmHg to obtain a high A copolyester having a molecular weight was obtained.

(3) When the content of each structural unit of the copolyester obtained in (2) above was measured by the above method, the terephthalic acid unit, ethylene glycol unit, 1,4-cyclohexane in the copolyester were measured. The contents of dimethanol unit, trimellitic acid unit, naphthoic acid unit and diethylene glycol unit were as shown in Table 7 below. (4) The physical properties of the copolyester obtained in (2) above were measured by the methods described above, and the results are shown in Table 7 below.
As shown in, the intrinsic viscosity is 1.12 dl / g, 270 ° C.
The melt viscosity (η ₁ ) at a shear rate of 0.1 rad / sec at a temperature of 270 ° C. is 1.29 × 10 ⁵ poises and a shear rate of 100 ra.
The melt viscosity (η ₂ ) at d / sec was 1.39 × 10 ⁴ poise, so the value of (1/3) log ₁₀ (η ₂ / η ₁ ) was −0.32. Further, the shark skin critical shear stress (σss) at 270 ° C. of the copolyester obtained in (2) above is 6.7 × 10 ⁶ dyne / cm ² ,
The shear stress (σ100) at a shear rate of 100 rad / sec was 3.1 × 10 ⁶ dyne / cm ² . In addition, the crystallinity (χ of the copolyester obtained in (2) above
c), glass transition temperature (Tg), melting point (Tm), cold crystallinity (Tcc), and heat of cold crystallization (ΔHcc) were measured by the above-mentioned methods. As shown in Table 7 below, 31%, 78 ° C, 238 ° C, 128 ° C and 9J /
g.

(5) Using the copolymerized polyester obtained in (2) above, using an extrusion blow molding apparatus (hollow molding machine "BM-304 / J2 type" manufactured by Placo Co., Ltd.) according to the method described above. Perform extrusion blow molding to obtain a capacity of 180
A bottle of 0 ml and a set weight of 80 g was produced, and the drawdown property of the parison at that time, blow moldability, transparency of the obtained bottle, gel generation rate, drop breakage height and drop impact strength were determined by the methods described above. When measured or evaluated, it was as shown in Table 13 below.

Examples 2 to 4 Terephthalic acid and ethylene glycol were used in the proportions shown in Table 7 below, and further alicyclic or alicyclic for the aliphatic bifunctional compound unit (a) or 1,4-cyclohexanedimethanol as an aliphatic bifunctional compound, a polyfunctional compound unit (b)
For trimellitic anhydride as a polyfunctional compound for use as a monofunctional compound and 2-naphthoic acid or 2,4,6-trimethoxybenzoic acid as a monofunctional compound for a monofunctional compound unit (c) in the proportions shown in Table 7. After the esterification reaction and the melt polycondensation reaction were carried out in the same manner as in Example 1 to produce a prepolymer chip of the copolyester, solid phase polymerization was carried out at the temperature and time shown in Table 7 below to carry out the copolymerization. Each polyester was produced. 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 Table 7 below. Further, using the copolymerized polyesters obtained in each of Examples 2 to 4, extrusion blow molding was performed in the same manner as in Example 1 to produce a bottle, and the drawdown property and blow moldability of the parison at that time were manufactured. The transparency, gel generation rate, drop breaking height and drop impact strength of the obtained bottle were measured or evaluated by the above-mentioned methods, and the results are shown in Table 13 below.

Examples 5 to 8 Terephthalic acid and ethylene glycol were used in the ratios shown in Table 8 below, and further alicyclic or alicyclic for the aliphatic bifunctional compound unit (a) or 1,4-Cyclohexanedicarboxylic acid, 1,3-propanediol or 2-butyl-2-ethyl-1,3-propanediol as an aliphatic bifunctional compound is used as the polyfunctional compound for the polyfunctional compound unit (b). As trimethylolpropane or trimellitic anhydride, and stearic acid, 2-naphthoic acid, polyethylene glycol monomethyl ether or stearyl alcohol as the monofunctional compound for the monofunctional compound unit (c) in the proportions shown in Table 8 below. Esterification reaction and melt polycondensation reaction are carried out in the same manner as in Example 1 to prepare a copolymerized polyester. After producing the polymeric chip, and subjected to solid phase polymerization at a temperature and time shown in Table 8 below, were prepared copolyester, respectively. 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 Table 8 below. Moreover, extrusion blow molding was carried out in the same manner as in Example 1 using the copolymerized polyester obtained in each of Examples 5 to 8 to produce a bottle, and the drawdown property and blow moldability of the parison at that time were produced. The transparency, gel generation rate, drop breaking height and drop impact strength of the obtained bottle were measured or evaluated by the above-mentioned methods, and the results are shown in Table 13 below.

Examples 9 to 10 Terephthalic acid and ethylene glycol were used in the proportions shown in Table 9 below, and further alicyclic or aliphatic bifunctional compound unit (a) was used.
1,4-as alicyclic or aliphatic bifunctional compounds for use in
Cyclohexanedimethanol, pentaerythritol or trimethylolpropane as the polyfunctional compound for the polyfunctional compound unit (b), and m-anisic acid or benzoic acid as the monofunctional compound for the monofunctional compound unit (c) are described below. Using the proportions shown in Table 9, the esterification reaction and the melt polycondensation reaction were carried out in the same manner as in Example 1 to produce a prepolymer chip of a copolyester, and then at the temperature and time shown in Table 9 below. Solid-state polymerization was carried out to produce each copolyester. 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, and the results are shown in Table 9 below. Using the copolymerized polyester obtained in each of Examples 9 and 10, extrusion blow molding was performed in the same manner as in Example 1 to produce a bottle, and the drawdown property and blow moldability of the parison at that time were manufactured. And the transparency of the resulting bottle,
The gel generation rate, drop fracture height, and drop impact strength were measured or evaluated by the methods described above, and the results are shown in Table 13 below.

Comparative Examples 1 to 4 Terephthalic acid and ethylene glycol were used in the proportions shown in Table 10 below, and further alicyclic or aliphatic bifunctional compound unit (a) was used.
Polyfunctional for the polyfunctional compound unit (b), with or without neopentyl glycol as alicyclic or aliphatic bifunctional compound for use, or with isophthalic acid as the bifunctional compound unit (a) Similar to Example 1 with trimethylolpropane, trimellitic anhydride or pentaerythritol as the compound and with or without benzoic acid or m-anisic acid as the monofunctional compound for the monofunctional compound unit (c). Then, an esterification reaction and a melt polycondensation reaction were performed to produce a prepolymer chip of a copolyester, and then solid phase polymerization was performed at the temperature and time shown in Table 10 below to produce a copolyester. 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 Table 1 below.
It was as shown in 0. In addition, the copolymerized polyester obtained in each of Comparative Examples 1 to 4 was used in Example 1.
Extrusion blow molding is performed in the same manner as above to manufacture a bottle,
At that time, the drawdown property of the parison, the blow moldability and the transparency of the obtained bottle, the gel generation rate, the drop fracture height and the drop impact strength were measured or evaluated by the above-mentioned methods, and the results are shown in Table 13 below. It was as shown.

Comparative Examples 5 to 8 Terephthalic acid and ethylene glycol were used in the proportions shown in Table 11 below, and further alicyclic or aliphatic bifunctional compound unit (a) was used.
1,4-cyclohexanedimethanol as a bifunctional compound for use in the above, and trimellitic anhydride or trimethylolpropane as a polyfunctional compound for the polyfunctional compound unit (b), and for a monofunctional compound unit (c) Using 2-naphthoic acid or benzoic acid as the monofunctional compound of Example 1, an esterification reaction and a melt polycondensation reaction were performed in the same manner as in Example 1 to produce a prepolymer chip of a copolyester, and then Table 11 below. Solid-state polymerization was carried out at the temperature and time shown in Table 1 to produce copolyesters (however, in Comparative Example 8, the prepolymer chips of the copolyester were amorphous, so solid-phase polymerization was not performed and the following extrusion blow was performed. Used as-is for molding). 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 and as shown in Table 11 below (however, as described above, Comparative Example 8 Was measured at 210 ° C.). Further, extrusion blow molding was performed in the same manner as in Example 1 using the copolymerized polyester obtained in each of Comparative Examples 5 to 8 to produce a bottle, and the drawdown property and blow moldability of the parison at that time were manufactured. The transparency, gel generation rate, drop breaking height, and drop impact strength of the obtained bottle were measured or evaluated by the above-mentioned methods, and the results are as shown in Table 13 below (however, comparison was made as described above). For Example 8, extrusion blow molding was performed at 210 ° C).

Comparative Examples 9 to 11 Terephthalic acid and ethylene glycol were used in the proportions shown in Table 12 below, and further alicyclic or alicyclic for the aliphatic bifunctional compound unit (a) or With or without 1,4-cyclohexanedimethanol as an aliphatic bifunctional compound, or an alicyclic or non-aliphatic aromatic bisphenol A ethylene oxide adduct (for 1 mol of bisphenol A). Esterification reaction and melting in the same manner as in Example 1 except that 2 mol of ethylene oxide was added) and neither of the compounds for the polyfunctional compound unit (b) and the monofunctional compound unit (c) was used. A polycondensation reaction was performed to produce prepolymer chips of copolyester or polyethylene terephthalate, which are shown in Table 12 below. To produce a copolyester or polyethylene terephthalate by performing solid phase polymerization at a temperature and time (however, since the prepolymer of the copolyester of Comparative Example 11 was amorphous, the following was used as it was without solid phase polymerization. Extrusion blow molding was performed). The contents and physical properties of each structural unit in the obtained polyesters were examined in the same manner as in Example 1, and the results are shown in Table 1 below.
2 (however, as described above, Comparative Example 1
1 was measured at 210 ° C.). In addition, using the polyesters obtained in each of Comparative Examples 9 to 11, extrusion blow molding was performed in the same manner as in Example 1 to produce a bottle, and the drawdown property, blow moldability and yield of the parison at that time were obtained. The transparency, gel generation rate, drop breakage height and drop impact strength of the obtained bottle were measured or evaluated by the above-mentioned methods, and were as shown in Table 13 below (however, as described above, Comparative Example 11 Was subjected to extrusion blow molding at 210 ° C.).

Compounds are shown by abbreviations in Tables 7 to 12 below, and the contents of the abbreviations are as shown in Table 6 below.

[0102]

[Table 6] Abbreviation: Compound TPA: terephthalic acid EG: ethylene glycol DEG: diethylene glycol PD: 1,3-propanediol BEPD: 2-butyl-2-ethyl-propanediol CHDM: 1,4-cyclohexanedimethanol CHDC: 1,4-cyclohexanedicarboxylic acid IPA : Isophthalic acid EOBPA: Bisphenol A ethylene oxide adduct (addition of 2 mol of ethylene oxide to 1 mol of bisphenol A) NPG: Neopentyl glycol TMA: Trimellitic anhydride TMP: Trimethylolpropane PENTA: Pentaerythritol NA: 2-Naphthoe Acid TMOBA: 2,4,6-trimethoxybenzoic acid STOH: Stearyl alcohol STA: Stearic acid APEG: Polyethylene glycol monomer Ether (molecular weight 1000) BA: Benzoic acid AA: m-anisic acid

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Embedded image

[0104]

[Table 8]

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[Table 9]

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[Table 10]

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[Table 11]

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[Table 12]

[0109]

[Table 13]

From the results of Tables 7 to 9 and Table 13 above,
Mainly composed of terephthalic acid units and ethylene glycol units, and based on the total number of moles of all the constituent units of the copolyester, the alicyclic or aliphatic bifunctional compound unit (a) is in the range of 1 to 4 mol%. Copolymer having a polyfunctional compound unit (b) in the range of 0.005 to 1 mol% and a monofunctional compound unit (c) in a range satisfying the above formula (I). In the case of Examples 1 to 10 in which the polyester is produced, it can be seen that the copolymerized polyester having an intrinsic viscosity suitable for melt molding such as extrusion blow molding can be smoothly produced in a short solid phase polymerization time of 30 hours or less. Moreover, when bottles were produced by extrusion blow molding using the copolymerized polyesters obtained in Examples 1 to 10, the drawdown time of the extruded parison was in the proper range of 16 to 24 seconds, and the maximum parison The difference between the diameter and the minimum diameter is 0.5 cm or less, the production amount of bottles is 120 or more per hour, and the percentage of poorly formed bottles is less than 10 out of 100 bottles. The drawdown property is excellent, and the average wall thickness of the obtained bottle is in the range of 0.3 mm or more and 0.7 mm or less, and the thickness unevenness is less than 0.3 mm,
It can be seen that the blow moldability is excellent. In addition, the bottles obtained in Examples 1 to 10 have haze values of 4 or less and b values of less than 2 and are excellent in transparency and surface beauty, and have a gel generation rate of 2.5%. It can be seen from the following that the generation of gels is extremely small, and in addition, the drop fracture height is 100 cm or more and the drop impact strength is high.

In contrast, Tables 10 and 13 above
From the results, it is mainly composed of a terephthalic acid unit and an ethylene glycol unit, but does not have an alicyclic or aliphatic bifunctional compound unit (a), and is a polyfunctional compound unit (b) only or a polyfunctional compound. In the case of Comparative Example 1 and Comparative Example 2 in which the copolyester having only the unit (b) and the monofunctional compound unit (c) is produced, the solid phase polymerization is 40 hours or more, and the polymerization takes a long time. It turns out that productivity is inferior. Moreover, when a bottle is produced by extrusion blow molding using the copolymerized polyester obtained in these comparative examples, the thickness unevenness of the bottle is 0.3.
mm or more and inferior in blow moldability, the obtained bottle has a haze value of 10 or more and poor transparency, and the generation rate of gel is more than 2.5% ( Comparative Example 2) shows that the appearance and touch are poor, and that the drop breaking height is 50 cm and the drop impact strength is small.

From the results shown in Tables 10 and 13 above, the alicyclic or aliphatic bifunctional compound unit (a) and the polyfunctional compound unit (b) which are mainly composed of terephthalic acid units and ethylene glycol units. However, the copolymerized polyester of Comparative Example 3 which has a monofunctional compound unit (c) has a drawdown time of 14 seconds for the extruded parison when a bottle is produced by extrusion blow molding. And the parison has a poor drawdown property, and when the bottle is manufactured by extrusion blow molding, the thickness unevenness of the bottle is 0.3 mm or more, and the blow moldability is poor. The haze value is 5.7 and the transparency is inferior due to the occurrence of surface and surface roughness, and the generation rate of the gel material exceeds 2.5%, and further, it is dropped and broken. Small drop impact strength a Saga 80 cm, it can be seen that a low quality. Then, in the case of Comparative Example 3, the solid phase polymerization takes 38 hours, and it can be seen that the productivity is low.

Further, from the results of Tables 10 and 13 above, the terephthalic acid unit and the ethylene glycol unit are mainly contained, and the bifunctional compound unit, the polyfunctional compound unit (b) and the monofunctional compound unit (c) are included. But
The copolymerized polyester of Comparative Example 4 in which the bifunctional compound unit was not an alicyclic or aliphatic bifunctional compound unit (a) had a bottle thickness unevenness of 0.45 mm when the bottle was manufactured by extrusion blow molding. It is inferior in blow moldability, and the resulting bottle is remarkably finely roughened on the surface. Therefore, the haze value is 8.5 and the transparency is inferior.
It was also inferior in touch. In addition, it can be seen that the bottle obtained using the copolyester of Comparative Example 4 has a drop breakage height of 50 cm, a small drop impact strength, and low quality.

From the results of Table 11 and Table 13 above, the alicyclic or aliphatic bifunctional compound unit (a) and the polyfunctional compound unit (b) which mainly consisted of terephthalic acid units and ethylene glycol units. And having a monofunctional compound unit (c), but alicyclic or aliphatic 2
The copolymerized polyesters of Comparative Examples 5 to 7 in which the proportion of the functional compound unit (a) or the polyfunctional compound unit (b) is out of the range of the present invention are inferior in drawdown property of the parison, and are extruded. When a bottle is manufactured by blow molding, the thickness unevenness of the bottle is 0.3 mm or more and the blow moldability is poor, and the obtained bottle has a haze value of 5 or more and is poor in transparency and drops. It can be seen that the breaking height is 50 to 70 cm, the drop impact strength is small, and the quality is low. In the case of Comparative Example 5 and Comparative Example 7, the solid phase polymerization was performed for 63 hours and 52 hours, respectively.
It takes time and the productivity is extremely low.

Further, from the results of Tables 11 and 13 above, the alicyclic or aliphatic bifunctional compound unit (a) and the polyfunctional compound unit (b) which are mainly composed of a terephthalic acid unit and an ethylene glycol unit. And having a monofunctional compound unit (c), but alicyclic or aliphatic 2
The copolymerized polyester of Comparative Example 8 in which the proportion of the functional compound unit (a) exceeded 4 mol% based on the total number of moles of all the constituent units of the copolymerized polyester was amorphous, so that the degree of polymerization was increased by solid phase polymerization. It could not be increased, and a high melt viscosity was not obtained at a temperature of 270 ° C., and extrusion blow molding could not be performed. Therefore, molding was barely possible.
Although extrusion blow molding was performed at a temperature of 0 ° C., the drawdown property of the parison was inferior, and when the bottle was manufactured by extrusion blow molding, uneven thickness of the bottle was 0.40.
It can be seen that it was inferior to the blow moldability because it was mm.
Moreover, the bottle obtained in Comparative Example 8 had a very small surface roughness due to the molding at a low temperature, and therefore had a haze value of 10.3 and was inferior in transparency and was inferior in tactile sensation. It was also found that the drop fracture height was 50 cm, the drop impact strength was small, and the quality was low.

Further, from the results of Tables 12 and 13 above, although it is mainly composed of a terephthalic acid unit and an ethylene glycol unit and has an alicyclic or aliphatic bifunctional compound unit (a), it is polyfunctional. The copolymerized polyester of Comparative Example 9 having neither the compound unit (b) nor the monofunctional compound unit (c) was inferior in the drawdown property of the parison, and the thickness of the bottle when the bottle was manufactured by extrusion blow molding. The unevenness is 0.5 mm and the blow moldability is inferior, and the obtained bottle has a haze value of 4.1 and is slightly inferior in transparency, and the drop breaking height is 50 cm.
It can be seen that the drop impact strength is low and the quality is low. Further, in the case of this Comparative Example 9, the solid phase polymerization was
It takes 2 hours and it can be seen that the productivity is extremely low.

From the results shown in Tables 12 and 13, the polyester produced by using only terephthalic acid and ethylene glycol and having the alicyclic or aliphatic bifunctional compound unit (a) And the polyester of Comparative Example 10 having no polyfunctional compound unit (b) and monofunctional compound unit (c) (the polyester of Comparative Example 10 is a diethylene glycol unit which is the above-mentioned undesired copolymerization unit). The drawdown time of the parison is 5 seconds or less, and the difference between the maximum diameter and the minimum diameter of the parison is 3.0 cm or more. It is found that extrusion blow molding is difficult in practice. Further, in the case of Comparative Example 10, the solid phase polymerization takes 67 hours, and it is understood that the productivity is extremely low.

From the results shown in Tables 12 and 13, the terephthalic acid unit and the ethylene glycol unit are mainly contained and the alicyclic or aliphatic bifunctional compound unit (a) is contained as the bifunctional compound unit. However, the bisphenol A ethylene oxide group adduct which is an aromatic diol unit is contained in a large proportion of 15.13 mol% based on the total number of moles of all constitutional units of the copolyester,
The copolyester of Comparative Example 11, which does not have the polyfunctional compound unit (b) and the monofunctional compound unit (c), was amorphous, and therefore the degree of polymerization could not be increased by solid-phase polymerization. The melt viscosity at the temperature of ℃ was so low that extrusion blow molding could not be performed. Therefore, the extrusion blow molding was performed at a temperature of 210 ℃, which was barely possible, but the drawdown of the parison was poor. It can be seen that, when the bottle was manufactured by extrusion blow molding, the thickness unevenness of the bottle was 0.45 mm, and the blow moldability was poor. In addition, the bottle obtained by using the copolyester of Comparative Example 11 was remarkably micro-roughened on the surface due to molding at low temperature, and therefore had a haze value of 9.5 and was inferior in transparency. Further, it is also found that the feel is inferior, the drop breaking height is 50 cm, the drop impact strength is small, and the quality is low.

<< Examples 11 to 12 and Comparative Examples 12 to 1
3> terephthalic acid and ethylene glycol in Table 14 below
1,4-cyclohexanedimethanol is used as the alicyclic or aliphatic bifunctional compound for the alicyclic or aliphatic bifunctional compound unit (a), and polyfunctional Esterification and melting as in Example 1, using trimellitic anhydride as the polyfunctional compound for the compound unit (b) and benzoic acid as the monofunctional compound for the monofunctional compound unit (c). After the polycondensation reaction was carried out to manufacture a prepolymer chip of the copolyester, solid phase polymerization was carried out at the temperature and time shown in Table 14 below to manufacture the copolyester. The content of each structural unit in the obtained polyester and the physical properties of the copolymerized polyester were examined in the same manner as in Example 1. The results are shown in Table 14 below. In addition, Examples 11 to 12 and Comparative Examples 12 to 1
Extrusion blow molding was carried out in the same manner as in Example 1 using the copolymerized polyester obtained in each of 3 to produce a bottle, and the drawdown property of the parison at that time, the blow moldability, and the transparency of the obtained bottle. The properties, gel generation rate, drop breakage height and drop impact strength were measured or evaluated by the above-mentioned methods and were as shown in Table 15 below. However, when the copolymerized polyester of Comparative Example 12 was subjected to extrusion blow molding, parison could not be formed, and therefore measurements other than the drawdown time could not be performed.
In Table 14, the compounds are shown by abbreviations,
The contents of the abbreviations are as shown in Table 6 above.

[0120]

[Table 14]

[0121]

[Table 15]

From the results of Tables 14 and 15 above, based on the total number of moles of all the constituent units of the copolyester, which consisted mainly of terephthalic acid units and ethylene glycol units, alicyclic or aliphatic bifunctional compounds were obtained. The compound unit (a) is in the range of 1 to 4 mol% and the polyfunctional compound unit (b) is in the range of 0.005 to 1 mol%, and the monofunctional compound unit (c) is the above formula. In the case of Examples 11 to 12 in which the copolyester having the range satisfying (I) is produced, as in the case of Examples 1 to 10, the solid phase polymerization time is 30 hours or less. It can be seen that a copolyester having an intrinsic viscosity suitable for melt molding such as extrusion blow molding can be smoothly produced. Moreover, when a bottle was produced by extrusion blow molding using the copolymerized polyesters obtained in Examples 11 to 12, as in Examples 1 to 10, excellent drawdown properties and blow moldability, Further, it can be seen that the obtained bottle is excellent in transparency and surface beauty, has very little generation of gel substance, and has high drop impact strength.

On the other hand, the alicyclic or aliphatic bifunctional compound unit (a) is mainly composed of a terephthalic acid unit and an ethylene glycol unit, and based on the total number of moles of all the constituent units of the copolyester. 1-4 mol%
And the polyfunctional compound unit (b) is 0.005
In the range of 1 mol% and having the monofunctional compound unit (c), the proportion of the monofunctional compound unit (c) is larger than that of the above formula (I). The copolyester could not sufficiently increase the degree of polymerization by melt polymerization and solid phase polymerization, and had a low viscosity. Therefore, even if this copolyester was subjected to extrusion blow molding, a parison could not be formed and a molded product could not be obtained.

Further, the alicyclic or aliphatic bifunctional compound unit (a) is mainly composed of a terephthalic acid unit and an ethylene glycol unit, and the alicyclic or aliphatic bifunctional compound unit (a) is from 1 to 4 based on the total number of moles of all the constituent units of the copolyester. A monofunctional compound unit (b) in the range of 0.005 to 1 mol% and a monofunctional compound unit (c). The copolymerized polyester of Comparative Example 13 in which the ratio of) is less than the range of the above formula (I) has a large extrusion unevenness and is poor in parison formability when it is subjected to extrusion blow molding to produce a bottle. At this time, the thickness unevenness of the bottle is 0.3 mm or more and the blow moldability is poor, and the resulting bottle has a haze value of 5 or more and is poor in transparency, and the generation of spots due to gel is remarkable. Yes Moreover falling fracture height smaller drop impact strength a 80 cm, it can be seen that a low quality.

[0125]

EFFECT OF THE INVENTION The copolymerized polyester of the present invention has a high melt viscosity, a low viscosity at a high shear rate, and a high viscosity at a low shear rate, and exhibits non-Newtonian properties. Melt fracture does not occur, the crystallization rate is suppressed, and since it has excellent properties that a gelled product does not occur, it is extremely excellent in melt molding, extrusion blow molding using the copolymerized polyester of the present invention, When melt molding such as injection / extrusion blow molding, extrusion molding, and injection molding is performed, there is no whitening or gelation, and excellent characteristics such as transparency, surface condition, appearance, and touch, and mechanical Characteristics, dimensional accuracy, heat resistance, moisture resistance,
It is possible to extremely smoothly manufacture a high-quality molded product excellent in various properties such as chemical resistance.

The copolymerized polyester of the present invention is
Among the above-mentioned melt molding, it has a high melt viscosity suitable for use in melt molding involving a melt extrusion step, particularly extrusion blow molding, and a good melt viscosity suitability, and therefore, the copolymerized polyester of the present invention is used. When extrusion blow molding is carried out, the drawdown property of the extruded parison is good, the drawdown time of the parison is kept within an appropriate range, the parison diameter becomes uniform, and the blow moldability is improved. Is good, and without causing troubles during molding, it is possible to smoothly produce a hollow molded product having a good shape and dimensional accuracy without distortion or deformation with a long length of 20 cm or more. It can also be used very suitably for extrusion blow molding of a large hollow molded product accompanied by extrusion of a parison. Further, in the case of the method for producing a copolyester of the present invention, the copolyester of the present invention having the above-mentioned excellent properties is produced in a short time, particularly in a shortened solid phase polymerization time, with good productivity and economically. Can be manufactured.

[Table 7]

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Claims (9)

[Claims] 1. A copolymerized polyester mainly composed of a terephthalic acid unit and an ethylene glycol unit and having another copolymerized unit; (2) The copolymerized polyester as another copolymerized unit, (I) at least one alicyclic or aliphatic bifunctional compound unit (a selected from alicyclic or aliphatic dicarboxylic acid units other than terephthalic acid units and ethylene glycol units, diol units and hydroxycarboxylic acid units) ) In an amount of 1 to 4 mol% based on the total number of moles of all constituent units of the copolyester; (ii) 3 or more carboxyl groups, hydroxyl groups and / or their ester-forming groups. The polyfunctional compound unit (b) derived from at least one of the polyfunctional compounds having the whole constitution of the copolyester In a proportion of 0.005 to 1 mol%, based on the total number of moles of positions; and (iii) derived from at least one monofunctional compound of monocarboxylic acids, monoalcohols and their ester-forming derivatives. Based on the total number of moles of all the constitutional units of the copolyester, the monofunctional compound unit (c) is represented by the following mathematical formula (I): ## EQU1 ## {20 × (n-2) × b} ≧ c ≧ {0.1 × (n−2) × b} (I) [wherein, b = the ratio (mol%) of the polyfunctional compound unit (b) in the copolyester c = the monofunctional compound unit in the copolyester ( c)
(Mole%) n = average number of functional groups in the polyfunctional compound that induces the polyfunctional compound unit (b)]. 2. The copolyester according to claim 1, wherein the alicyclic or aliphatic bifunctional compound unit (a) is a cyclohexanedimethanol unit and / or a cyclohexanedicarboxylic acid unit. 3. The copolyester according to claim 1, which has an intrinsic viscosity of 0.8 to 1.5 dl / g. 4. 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, shear rate 10 at a temperature of 270 ° C.
Melt viscosity (η ₂ ) at 0 rad / sec is 5 × 10 ^{3 to} 5 × 1.
0 ⁵ is poise, and the melt viscosity (eta ₁₎ and the melt viscosity of (eta ₂₎ is the following formula (II); [Number 2] _{-0.7 ≦ (1/3) log 10 (} η 2 / The copolyester according to any one of claims 1 to 3, which satisfies η ₁ ) ≦ −0.2 (II). 5. A sharkskin critical shear stress (σss) at a temperature of 270 ° C. is 1 × 10 ⁶ dyne / cm ² or more, and a shear rate of 100 r at a temperature of 270 ° C.
The copolyester according to any one of claims 1 to 4, wherein the shear stress (σ100) at ad / sec is not more than the sharkskin critical shear stress (σss). 6. A molded article made of the copolyester according to claim 1. 7. The molded article according to claim 6, which is an extrusion blow molded article. 8. A method for producing a molded article by carrying out extrusion blow molding using the copolymerized polyester according to claim 1. 9. A method for producing a copolyester mainly composed of a terephthalic acid unit and an ethylene glycol unit and having another copolymerized unit; (1) a dicarboxylic acid component comprising terephthalic acid or an ester-forming derivative thereof. In addition to the above-mentioned main dicarboxylic acid component and diol component, it further comprises (a)
At least one alicyclic or aliphatic bifunctional compound selected from alicyclic or aliphatic dicarboxylic acids, hydroxycarboxylic acids, their ester-forming derivatives and alicyclic or aliphatic diols other than ethylene glycol (B) at least one polyfunctional compound having three or more carboxyl groups, hydroxyl groups and / or their ester-forming groups; and (c) at least monocarboxylic acid, monoalcohol and their ester-forming derivatives. A reaction raw material containing one of the above-mentioned alicyclic or aliphatic 2
The content of the functional compound is such that the ratio of the alicyclic or aliphatic bifunctional compound unit (a) derived from the alicyclic or aliphatic bifunctional compound is the total number of moles of all constituent units of the copolyester. The content of the polyfunctional compound in the reaction raw material is such that the proportion of the polyfunctional compound unit (b) derived from the polyfunctional compound is in the range of 1 to 4 mol%. The amount of the monofunctional compound in the reaction raw material is 0.005 to 1 mol% based on the total number of moles of all the constituent units of the copolyester; The ratio of the derived monofunctional compound unit (c) is based on the total number of moles of all the constitutional units of the copolyester, and is represented by the following mathematical formula (I): [Formula 3] {20 × (n−2) × b } ≧ c ≧ {0.1 × (n−2) × b} (I) [expression , B = the copolymerization ratio of the polyfunctional compound units (b) in the polyester (mol%) c = copolymerized in the polyester monofunctional compound units (c)
Ratio (mol%) n = the average number of functional groups of the polyfunctional compound that induces the polyfunctional compound unit (b)]; the reaction raw material is subjected to an esterification reaction or a transesterification reaction. After that, it is melt-polycondensed to form a polyester prepolymer; and (2) the polyester prepolymer obtained in the above step (1) is solid-phase polymerized.
5. The method for producing a copolyester according to any one of 5 to 5.