JP2003191929A - Blow molded container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow molded container that can be made of polyester resin by direct blow molding and is excellent in its transparency, heat resistance and shock resistance. <P>SOLUTION: The blow molded container that can be made of polyester resin (A) by direct blow molding, where the polyester resin has dicarboxylic acid constitutional unit and diol constitutional unit which are (1) the unit of dicarboxylic acid of at least 5-60 mole % of dicarboxylic acid constitutional unit with cyclic acetal skeleton or (2) polyester resin with the diol constitutional unit of 5-60 mole % and cyclic acetal skeleton, intrinsic viscosity of 0.3-1.5 (dl/g), glass transition temperature of 90°C of higher, quantity of heat at crystallized heating peak of 4 J/g or less in the temperature falling and melt strength of 3 cN or higher. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a large melt strength,
The present invention relates to a hollow container using a polyester resin suitable for direct blow molding and having excellent transparency, heat resistance and impact resistance.

[0002]

2. Description of the Related Art Direct blow molding is a method for molding a hollow container in which a thermoplastic resin is melt-extruded and then blow molded, but it has features such as easy temperature control during molding and high production efficiency. . Hollow containers made by direct blow molding were mainly made of polyvinyl chloride because of their excellent transparency, moldability, impact resistance, and heat resistance, but due to environmental problems, substitution with other resins was possible. It is progressing.

As an alternative resin, there are polyolefin resins such as polyethylene and polypropylene which have a large melt strength and are easy to perform direct blow molding. The direct blow containers molded from these resins are turbid white due to the crystallization of the resin. There is a problem that it is difficult to use for applications requiring transparency.

Polyethylene terephthalate (hereinafter PET) is used as a resin for direct blow bottles having excellent transparency.
Abbreviated) and modified PET and various polyester-based ones have been proposed. PET has excellent transparency, mechanical strength, chemical resistance, etc. and is widely used as sheets, films, and containers. However, in direct blow molding, the melt strength is small, so drawdown during molding and bottle Variations in wall thickness occur. Further, there are problems such as a decrease in impact strength due to crystallization, a decrease in transparency, and a lack of heat resistance.

Therefore, it has been attempted to use modified PET obtained by copolymerizing 1,4-cyclohexanedimethanol and isophthalic acid as a resin for direct blow molding. For example, in JP-A-7-207003,
Although 4-cyclohexanedimethanol-modified PET has been proposed, this resin has poor thermal stability and not only deteriorates the color tone during molding, but also does not achieve improvement in heat resistance. Further, JP-A-11-158260 proposes a modified PET obtained by copolymerizing isophthalic acid.
This resin has not been improved in heat resistance and impact resistance. Japanese Patent Laid-Open No. 2000-178347 proposes PET in which an alicyclic diol is copolymerized, but it cannot be said that heat resistance is sufficient, transparency, heat resistance, mechanical strength are good, and melt strength is high. A large polyester resin suitable for direct blow molding has not been proposed yet.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is directed to blow molding a copolymer polyester resin having a large melt strength and suitable for direct blow molding to obtain transparency, heat resistance and impact resistance. To provide a good hollow container.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have polymerized a raw material monomer containing a compound in which at least one of a dicarboxylic acid component and a diol component has a cyclic ether skeleton. It was found that the use of the polyester resin obtained by the method increases the melt strength of the polyester resin, and the hollow container obtained by direct blow molding the polyester resin has good transparency, heat resistance, and impact resistance. The invention was reached.

That is, the present invention is a polyester resin having a constitutional unit derived from a dicarboxylic acid and a constitutional unit derived from a diol, wherein at least (1) 5 to 60 mol% of the constitutional unit of the dicarboxylic acid is a cyclic acetal. A polyester resin which is a dicarboxylic acid unit having a skeleton or (2) 5 to 60 mol% of the diol constitutional unit is a diol unit having a cyclic acetal skeleton, and has the following physical properties (a) to (d): It is an invention relating to a hollow container obtained by direct blow molding of the polyester resin (A). (B) 2 using a mixed solvent having an intrinsic viscosity of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 4: 6
The measured value at 5 ° C. is 0.3 to 1.5 (dl / g). (B) The glass transition temperature measured by a differential scanning calorimeter is 90 ° C. or higher. (C) The calorific value of the crystallization exothermic peak at the time of temperature decrease measured by a differential scanning calorimeter is 4 J / g or less. (D) The melt strength is 3 cN or more.

The present invention will be described in detail below. The polyester resin (A) of the present invention comprises (1) a dicarboxylic acid unit having a cyclic acetal skeleton (a structural unit derived from a dicarboxylic acid having a cyclic acetal skeleton) in an amount of 5 to 60.
Mol% of dicarboxylic acid constitutional unit and diol constitutional unit not having cyclic acetal skeleton, (2) dicarboxylic acid constitutional unit not having cyclic acetal skeleton and diol unit having cyclic acetal skeleton (derived from diol having cyclic acetal skeleton) 5 to 60 mol% of the diol structural unit, or (3) 5 to 60 mol% of the dicarboxylic acid structural unit having a cyclic acetal skeleton and 5 to 5 diol units having a cyclic acetal skeleton. It is a polyester resin composed of a diol constitutional unit containing 60 mol%.

The diol having a cyclic acetal skeleton used in the polyester resin (A) used in the present invention is preferably a compound represented by the general formula (1) or (2).

[Chemical 5]

[Chemical 6]

In the general formulas (1) and (2), R ¹ and R ² are each independently an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and carbon. Number is 6 to 1
Represents an organic group selected from the group consisting of 0 aromatic groups, preferably a methylene group, an ethylene group, a propylene group, a butylene group or structural isomers thereof, for example, an isopropylene group and an isobutylene group. R ³ is an organic group selected from the group consisting of an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, preferably methyl. Represents a group, an ethyl group, a propyl group, a butyl group, or a structural isomer thereof, for example, an isopropyl group or an isobutyl group. The compounds of the general formulas (1) and (2) include 3,9-bis (1,1-dimethyl-2-
Hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane Etc. are particularly preferable.

The diol other than the diol having a cyclic acetal skeleton of the polyester resin (A) used in the present invention is not particularly limited, but ethylene glycol,
Trimethylene glycol, 1,4-butanediol,
Aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol and neopentyl glycol; polyether compounds such as polyethylene glycol, polypropylene glycol and polybutylene glycol; 1,3-cyclohexane Dimethanol, 1,4-cyclohexanedimethanol, 1,2-decahydronaphthalene dimethanol, 1,3-decahydronaphthalene dimethanol, 1,
4-decahydronaphthalenedimethanol, 1,5-decahydronaphthalenedimethanol, 1,6-decahydronaphthalenedimethanol, 2,7-decahydronaphthalenedimethanol, tetralindimethanol, norbornenedimethanol, tricyclodecandime Alicyclic diols such as methanol and pentacyclododecandimethanol;
4,4 '-(1-methylethylidene) bisphenol,
Methylene bisphenol (bisphenol F), 4,
Bisphenols such as 4'-cyclohexylidene bisphenol (bisphenol Z) and 4,4'-sulfonylbisphenol (bisphenol S); alkylene oxide adducts of the bisphenols; hydroquinone, resorcin, 4,4'-dihydroxybiphenyl, 4 ，
Examples thereof include aromatic dihydroxy compounds such as 4′-dihydroxydiphenyl ether and 4,4′-dihydroxydiphenylbenzophenone; and alkylene oxide adducts of the aromatic dihydroxy compounds. Ethylene glycol is particularly preferable from the viewpoint of mechanical performance, economical efficiency, etc. of the hollow container of the present invention.

The above-mentioned effect becomes more remarkable when the proportion of ethylene glycol in the diol component (b2) is preferably 20 to 99 mol%, more preferably 30 to 99 mol%, and particularly preferably 40 to 99 mol%. Become.

The dicarboxylic acid having a cyclic ether skeleton is preferably a compound represented by the general formula (3) or the general formula (4).

[Chemical 7]

[Chemical 8]

In the general formulas (3) and (4), R ³ is the same as above, R ⁴ and R ⁵ are each independently an aliphatic group having 1 to 10 carbon atoms, and 3 to 10 carbon atoms. An alicyclic group and an organic group selected from the group consisting of aromatic groups having 6 to 10 carbon atoms, preferably a methylene group, an ethylene group,
It represents a propylene group, a butylene group or structural isomers thereof, for example, an isopropylene group and an isobutylene group. R ⁶
And R ⁷ each independently represent a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group, preferably a hydrogen atom or a methyl group. Examples of the compounds of the general formulas (3) and (4) include 3,9-bis (1,1-dimethyl-2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 5-carboxy-5-ethyl-2- (1,1-dimethyl-2-carboxyethyl)-
1,3-dioxane and the like are particularly preferable.

The dicarboxylic acid other than the dicarboxylic acid having a cyclic acetal skeleton of the polyester resin (A) used in the present invention is not particularly limited, but succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid. , Sebacic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, decanedicarboxylic acid, norbornanedicarboxylic acid, tricyclodecanedicarboxylic acid, pentacyclododecanedicarboxylic acid and other aliphatic dicarboxylic acids and their ester-forming derivatives; terephthalic acid,
Examples thereof include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and tetralindicarboxylic acid, and ester-forming derivatives thereof.

Polyester resin (A) used in the present invention
Is a diol (b1) used in the present invention, and a diol having a cyclic acetal skeleton in the dicarboxylic acid (a1) or the dicarboxylic acid is 5 to 60 mol% in the components, and preferably 10 to 50 mol%. , And more preferably 15 to 40 mol%. Melt strength of 5 mol% or more,
Sufficient heat resistance and transparency are obtained, and when the amount is 60 mol% or less, excellent impact resistance of the resin is obtained. Hollow container obtained by direct blow molding the polyester resin for hollow containers produced in the above proportion, can be stably molded without causing drawdown during molding, shows good transparency, impact resistance, hollow container When it is left to stand overnight after being filled with hot water of 85 ° C., its height and volume are maintained, and good heat resistance is exhibited.

From the viewpoint of mechanical performance of the hollow container of the present invention, aromatic dicarboxylic acid and its ester-forming derivative are preferable, and from the viewpoint of economy, terephthalic acid and its ester-forming derivative are particularly preferable. Also, from the viewpoint of heat resistance,
6-Naphthalenedicarboxylic acid and its ester-forming derivatives are preferred.

Polyester resin (A) used in the present invention
Is an aromatic dicarboxylic acid unit, preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 9 mol%.
It is 0 mol% or more. By setting the above ratio, the hollow container of the present invention has more excellent heat resistance and mechanical performance.

By introducing a dicarboxylic acid and / or diol structural unit having a cyclic acetal skeleton into the polyester resin (A) of the present invention, the glass transition temperature is raised and heat resistance can be imparted to the hollow container. At the same time, the melt strength is increased and drawdown does not occur, and a hollow container with less variation in wall thickness can be obtained. In addition, since the crystallinity decreases, even in a thick container, there is no partial crystallization, whitening associated therewith, impact resistance decrease, etc., good transparency, and excellent mechanical strength. A hollow container is obtained.

The glass transition temperature of the polyester resin (A) used in the present invention measured by a differential scanning calorimeter is preferably 90 ° C. or higher, more preferably 10
The temperature is 0 ° C or higher, more preferably 110 ° C or higher. When the glass transition temperature is 90 ° C. or higher, the effect of improving heat resistance can be obtained.
By setting the glass transition temperature to 90 ° C or higher
When filled with hot water of 5 ° C. and left to stand overnight, the height and volume are maintained and good heat resistance is exhibited. Further, by introducing 2,6-naphthalenedicarboxylic acid and / or its ester-forming derivative, a particularly high glass transition temperature is obtained, and 95 ° C.
When it is left to stand overnight after being filled with hot water, its height and volume are maintained, and particularly good heat resistance is exhibited.

The calorific value of the crystallization exothermic peak of the polyester resin used in the present invention when the temperature is lowered is preferably 4 J /
g or less, and more preferably 1 J / g or less. When the amount of heat of the crystallization exothermic peak at the time of cooling is 4 J / g or less, the crystallinity can be prevented from increasing, and the transparency and impact resistance can be maintained.

Intrinsic viscosity of the polyester resin used in the present invention (measured in a mixed solvent having a mass ratio of phenol and 1,1,2,2-tetrachloroethane of 6: 4 at 25 ° C.)
Is preferably in the range of 0.3 to 1.5 dl / g,
The range is more preferably 0.5 to 1.3 (dl / g), and further preferably 0.7 to 1.1 (dl / g). When the content is 0.3 dl / g or more, the strength of the hollow container is sufficient, and when the content of 1.5 is 5 dl / g or less, the moldability is good.

The melt strength of the polyester resin used in the present invention is preferably 3 cN or more, more preferably 5 cN.
N or more, particularly preferably 7 cN or more. When the melt strength is 3 cN or more, drawdown is less likely to occur during direct blow molding, and variations in wall thickness of the hollow container can be reduced. In the present invention, when a capillary having a nozzle diameter of 1 mm and a nozzle length of 10 mm is used in the present invention, the melt viscosity at a shear rate of 100 (1 / sec) is 1
The temperature at which the pressure was 400 Pa · s was examined, the resin was extruded at this temperature at a crosshead speed of 10 mm / min, and the load when the extruded strand was wound at a speed of 40 m / min was taken as the melt strength.

The polyester resin used in the present invention may contain monoalcohols such as butyl alcohol, hexyl alcohol and octyl alcohol, and trihydric or higher polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol within the range not impairing the object of the present invention. A monocarboxylic acid such as a polyhydric alcohol, benzoic acid, propionic acid or butyric acid can also be used.

Further, various molding aids and additives such as fillers, colorants, reinforcing agents, surface smoothing agents, leveling agents, curing reaction accelerators, light stabilizers, ultraviolet absorbers, plasticizers, Antioxidants, extenders, matting agents, drying regulators, antistatic agents, antisettling agents, surfactants, flow improvers, drying oils, waxes, thermoplastic oligomers and the like may also be included.

The method for producing the polyester resin used in the present invention is not particularly limited, and conventionally known methods can be applied. For example, a melt polymerization method such as a transesterification method and a direct esterification method, or a solution polymerization method can be mentioned. The transesterification catalyst, the esterification catalyst, the etherification inhibitor, the polymerization catalyst used for the polymerization, the various stabilizers such as the heat stabilizer and the light stabilizer, and the polymerization regulator may be those conventionally known. As a transesterification catalyst, compounds such as manganese, cobalt, zinc, titanium, calcium,
Examples of esterification catalysts include compounds such as manganese, cobalt, zinc, titanium and calcium, and examples of etherification inhibitors include amine compounds. Examples of the polycondensation catalyst include compounds such as germanium, antimony, tin and titanium. It is also effective to add various phosphorus compounds such as phosphoric acid, phosphorous acid and phenylphosphonic acid as heat stabilizers. Other light stabilizers, antistatic agents, lubricants,
You may add antioxidant, a mold release agent, etc. Further, in the direct esterification method, water may be added to improve the slurry property.

The method of forming a hollow container by direct blow molding of the polyester resin (A) used in the present invention is no different from the conventional hollow container molding method of polyvinyl chloride, polyethylene or polypropylene.
For example, a method of forming a molten parison with an extruder or an injection molding machine and performing blow molding in a blow mold can be adopted.

[0029]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

[Preparation of Hollow Container] A polyester resin was extruded from an extruder having a cylinder temperature of 240 to 270 ° C. to prepare a parison in a molten state, which was directly blown at a blow mold cooling temperature of 15 ° C. It was molded to obtain a hollow container having a volume of 300 ml.

[Evaluation of Resin] (1) Glass Transition Temperature, Crystallization Exothermic Peak at Falling Temperature The glass transition temperature (Tgm) of the polyester resin is
Shimadzu Corporation differential scanning calorimeter (model: DSC
/ TA-50WS), about 10 mg of the sample was placed in an aluminum non-sealed container, and nitrogen gas (30 ml / mi was used).
n) The temperature was measured at a temperature rising rate of 20 ° C./min in the air flow, and the temperature changed by 1/2 of the difference between the baselines before and after the transition of the DSC curve was defined as the glass transition temperature. In addition, the crystallization exothermic peak during cooling (hereinafter referred to as “ΔHc”) means 2 after measuring the above Tg.
It is a value obtained from the area of an exothermic peak that appears when the temperature is lowered at a temperature lowering rate of 10 ° C./min after holding at 80 ° C. for 1 minute. (2) It was measured under constant temperature at 25 ° C. using an intrinsic viscosity mixed solvent (mass ratio: phenol / 1,1,2,2-tetrachloroethane = 6/4). (3) As a melt strength measuring device, a capillograph manufactured by Toyo Seiki was used. A capillary with a nozzle diameter of 1 mm and a nozzle length of 10 mm was used.
First, the melt viscosity at a shear rate of 100 (1 / sec) is 1
The temperature at which the pressure was 400 Pa · s was examined, the resin was extruded at this temperature at a crosshead speed of 10 mm / min, and the load when the extruded strand was wound at a speed of 40 m / min was taken as the melt strength. (4) Haze The polyester resin was melt extruded to prepare a sheet having a thickness of 200 μm, and the haze of this sheet was measured. JI
According to SK-7105 and ASTM D1003, the measuring device is a haze value measuring device manufactured by Nippon Denshoku Industries Co., Ltd. (model: CO
H-300A) was used.

[Evaluation of Hollow Container] (1) Blow Moldability The presence or absence of drawdown during blow molding and the thickness unevenness of the hollow container were evaluated in the following three stages. ◯: No drawdown and small thickness unevenness Δ: Drawdown or large thickness unevenness X: Drawdown and large thickness unevenness (2) Visual observation of the appearance of the transparent hollow container Then, the evaluation was made according to the following three grades. ◯: Transparency is good as a whole △: Whitening is recognized in part such as the mouth and bottom ×: Whitening is recognized in the whole (3) Heat at 85 ° C and 95 ° C (± 1 ° C) in the heat-resistant hollow container After filling with water, the mixture was allowed to stand overnight, and the heat resistance was evaluated according to the following criteria based on the height and volume retention. 5 samples each. ◯: Height retention rate is 99% or more and capacity retention rate is 9
8.5% or more △: Height retention rate is less than 99% or capacity retention rate is 9
Less than 8.5% x: Height retention is less than 99% and capacity retention is 9
Less than 8.5% (4) Impact resistance A bottle filled with water was stored overnight at 5 ° C., and it was cracked by dropping it from the height of 1.0 m with the bottom of the hollow container down onto the concrete floor. The number was evaluated. Number of samples: 15 The results are shown in Tables 1 to 4.

In Tables 1 to 4, dimethyl terephthalate was designated as "D".
MT ", dimethyl 2,6-naphthalenedicarboxylate as NDCM, and 3,9-bis (2-carboxyethyl)
2,4,8,10-Tetraoxaspiro [5,5] undecane was designated as "SPD" and 5-methylol-5-ethyl-
2- (1,1-dimethyl-2-carboxoxyethyl)
-1,3-dioxane is "DOD", ethylene glycol is "EG", 3,9-bis (1,1-dimethyl-
2-Hydroxyethyl) 2,4,8,10-tetraoxaspiro [5,5] undecane was designated as "SPG" and 5-methylol-5-ethyl-2- (1,1-dimethyl-2-).
Hydroxyethyl) -1,3-dioxane is "DOG"
And 1,4-cyclohexanedimethanol into "CHD
It is abbreviated as "M".

[Synthesis of Resin] Examples 1 to 8 and Comparative Examples 1 to 6 Packed tower type rectification column, partial condenser, total condenser, cold trap,
A 150-liter (L) polyester production apparatus equipped with a stirring blade, a heating device, and a nitrogen introduction tube was charged with the monomers in the amounts shown in Tables 1 to 4, and manganese acetate tetrahydrate was added to the dicarboxylic acid component in an amount of 0. 03 mol% was added and the temperature was raised under normal pressure and nitrogen atmosphere. The temperature was raised to 200 ° C., and transesterification reaction was performed. The reaction conversion rate of the dicarboxylic acid component is 90 mol%
After the above, 0.02 mol% of antimony trioxide and 0.06 mol% of trimethyl phosphate are added to the dicarboxylic acid component, the temperature is raised and the pressure is gradually reduced, and finally 270
A polycondensation reaction was carried out at a temperature of 0.1 kPa or less. The viscosity of the reaction product gradually increased, and the reaction was terminated at the time when the melt viscosity became appropriate, and the polyester resins shown in Tables 1 to 4 were obtained.
The evaluation results of these resins are shown in Tables 1 to 4.

[Production of Hollow Container] Next, the polyester resin obtained above was extruded from an extruder having a cylinder temperature of 240 to 270 ° C. to produce a molten parison, which was cooled with a blow mold at a cooling temperature of 15 Direct blow molding was performed under the condition of ° C to obtain a hollow container having a volume of 300 ml.
The evaluation results are shown in Tables 1 to 4.

Table 1 Example Number Example 1 Example 2 Example 3 Example 4 Monomer Charge (mol) DMT 262.6 224.5-112.9 DCM--235.9 112.9 EG 407.0 401.8 389.2 361.4 SPG 39.4 69.6 11.8 45.2 Evaluation of polyester resin Tg (° C) 93 103 131 118 ΔHc (J / g) 1.4 0.0 3.5 0.0 IV (dl / g) 0.70 0.73 0.70 0.71 Melt strength (cN) 4.5 8.5 8.5 4.0 6.0 Formability ○ ○ ○ ○ Evaluation of hollow container Transparency ○ ○ ○ ○ Heat resistance (85 ℃) ○ ○ ○ ○ Heat resistance (95 ℃) △ ○ ○ ○ Haze (%) 1.0 0.2 1.5 0.4 Impact resistance 0/15 0/150 / 15 0/15

Table 2 Example No. Example 5 Example 6 Example 7 Example 8 Example 8 Monomer Charge (mol) DMT 124.4 99.4 NDCM 192.0 124.4 185.6 99.4 SPD − − 46 4-DOD--49.7 EG 393.6 398.0 417.5 447.3 DOG 86.4 24.9- Evaluation of polyester resin Tg (° C) 137 108 131 113 ΔHc (J / g). ) 0.0 1.0 0.1 0.0 IV (dl / g) 0.76 0.69 0.71 0.73 melt strength (cN) 13.5 4.5 6.0 5.0 moldability ○ ○ ○ ○ Evaluation of hollow container Transparency ○ ○ ○ ○ Heat resistance (85 ℃) ○ ○ ○ ○ Heat resistance (95 ℃) ○ ○ ○ ○ Haze (%) 0.2 1.2 0.3 0.5 Impact resistance 0/15 0/15 0/15 0/15

Table 3 Example No. Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Monomer charge (mol) DMT 312.2-273.6 306.8 NDCM-247.7 --- EG 530.8 421. 1 456.9 502.4 SPG --- 9.0 CHDM--90.3- Evaluation of polyester resin Tg (° C) 84 125 86 86 ΔHc (J / g) 35.5 1.0 0.1 28 .6 IV (dl / g) 0.76 0.69 0.71 0.70 Melt strength (cN) 0.1 1.0 0.6 1.5 1.5 Moldability × △ △ △ Evaluation of hollow container Transparency △ ○ ○ △ Heat resistance (85 ° C) × ○ △ △ Heat resistance (95 ° C) × ○ × × Haze (%) 2.4 1.6 0.2 2.2 Impact resistance 1/150/150 / 15 1/15

Table 4 Example No. Comparative Example 5 Comparative Example 6 Monomer charge (mol) DMT 171.6 NDCM 150.1 EG 317.4 277.7 SPG 111.5 97.6 Evaluation Tg of polyester resin (° C.) 124 168 ΔHc (J / g) 0.0 0.0 IV (dl / g) 0.72 0.71 Melt strength (cN) 15.5 17.5 Moldability ○ ○ Hollow container evaluation transparency ○ ○ Heat resistance (85 ° C) ○ ○ Heat resistance (95 ° C) ○ ○ Haze (%) 0.3 0.2 Impact resistance 9/15 5/15

[0040]

The hollow container obtained by direct blow molding the polyester resin used in the present invention is excellent in transparency, heat resistance and impact resistance, and the present invention has great industrial significance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shojiro Kuwahara             5-6 Higashi-Hachiman 5-2, Hiratsuka City, Kanagawa Prefecture             Ryogas Chemical Co., Ltd. Hiratsuka Research Center F-term (reference) 3E033 BA17 BB01 CA03 CA07 CA18                       FA03                 4F071 AA47 AA83 AA86 AA88 AF43                       AH05 BB06 BC04 BC17                 4J029 AA03 AB07 AC02 AD01 AD07                       AD10 AE18 BA03 BF30 CB06A                       CC06A CF19 HA01 HB01                       HB03A JC481 JF471 KB02                       KE02

Claims (8)

[Claims] 1. A polyester resin having a dicarboxylic acid constitutional unit and a diol constitutional unit, at least:
(1) Whether 5 to 60 mol% of the dicarboxylic acid constitutional unit is a dicarboxylic acid unit having a cyclic acetal skeleton,
(2) Direct blow molding of a polyester resin (A) in which 5 to 60 mol% of the diol constitutional unit is a diol unit having a cyclic acetal skeleton and which has the following physical properties (a) to (d) Hollow container obtained by (B) 2 using a mixed solvent having an intrinsic viscosity of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 4: 6
The measured value at 5 ° C. is 0.3 to 1.5 (dl / g). (B) The glass transition temperature measured by a differential scanning calorimeter is 90 ° C. or higher. (C) The calorific value of the crystallization exothermic peak at the time of temperature decrease measured by a differential scanning calorimeter is 4 J / g or less. (D) The melt strength is 3 cN or more. 2. The hollow container according to claim 1, wherein the diol having a cyclic acetal skeleton is a diol represented by the following general formula (1) or (2). [Chemical 1] (In the formula, R ¹ and R ² are each independently a carbon number of 1
Represents an organic group selected from the group consisting of an aliphatic group having 10 to 10, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. ) [Chemical 2] (In the formula, R ¹ is the same as above, and R ³ has 1 to 1 carbon atoms.
It represents an organic group selected from the group consisting of an aliphatic group having 0, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms. ) 3. The hollow container according to claim 1, wherein the dicarboxylic acid having a cyclic acetal skeleton is a dicarboxylic acid represented by the following general formula (3) or (4). [Chemical 3] (In the formula, R ⁴ and R ⁵ each independently have a carbon number of 1 to
Represents an organic group selected from the group consisting of an aliphatic group having 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and an aromatic group having 6 to 10 carbon atoms, and R ⁶ and R ⁷ are each independently Hydrogen atom,
It represents a methyl group, an ethyl group, or an isopropyl group. ) [Chemical 4] (In the formula, R ³ , R ⁴ , R ⁶ and R ⁷ are the same as above.) 4. A diol having a cyclic acetal skeleton is 3,9-bis (1,1-dimethyl-2-hydroxyethyl) 2,4,8,10-tetraoxaspiro [5.
5] Undecane or 5-methylol-5-ethyl-
2- (1,1-dimethyl-2-hydroxyethyl) 1,
The hollow container according to claim 1, which is 3-dioxane. 5. The dicarboxylic acid having a cyclic acetal skeleton is 3,9-bis (1,1-dimethyl-1-carboxyethyl) 2,4,8,10-tetraoxaspiro [5.5] undecane, or The hollow container according to claim 1, which is 5-methylol-5-ethyl-2- (1,1-dimethyl-1-carboxyethyl) 1,3-dioxane. 6. The hollow container according to claim 1, wherein 90 to 100 mol% of the dicarboxylic acid constituent unit of the polyester resin (A) is an aromatic dicarboxylic acid. 7. The terephthalic acid accounts for 50 to 100 mol% of the dicarboxylic acid constituent units of the polyester resin (A),
The glass transition temperature of the polyester resin (A) is not less than ° C, and the polyester resin (A) is obtained by direct blow molding.
The hollow container according to any one of 1 to 4. 8. The polyester resin (A) comprises dicarboxylic acid constitutional units in an amount of 50 to 100 mol% of 2,6-naphthalenedicarboxylic acid, and the polyester resin (A) has a glass transition temperature of 100 ° C. or higher and is direct. The hollow container according to any one of claims 1 to 4, which is obtained by blow molding.