JPH10204268A - Polyester hollow molded body - Google Patents

Abstract

(57) [Problem] To provide a polyester hollow molded article having extremely excellent heat resistance. SOLUTION: A polyester hollow molded article comprising a resin composition comprising polyethylene terephthalate at least 80 mol% of a constituent unit of which is an ethylene terephthalate unit and a specific polyetherimide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molded article made of polyester, and more particularly to a hollow molded article made of polyethylene terephthalate, which is particularly excellent in heat resistance, gas barrier properties, transparency and alkali washing resistance.

[0002]

2. Description of the Related Art Conventionally, glass has been widely used as a material for containers of seasonings, oils, juices, carbonated drinks, beer, sake, cosmetics, detergents, and the like. However, since the production cost of glass is high, a method of recovering the container after normal use and recycling it is adopted. Further, the glass container has drawbacks such as easy breakage and inconvenient handling.

[0003] The conversion from glass containers to plastic containers is rapidly progressing in an attempt to overcome these disadvantages of glass containers. Among these plastic materials, polyethylene terephthalate has excellent mechanical strength, heat resistance, transparency and gas barrier properties, so it is used as a material for containers for juices, soft drinks, carbonated drinks, seasonings, detergents, cosmetics, etc. Have been.

[0004] However, depending on the application, sufficient heat resistance is not enough to perform sufficient sterilization and filling at a high temperature, the alkali cleaning temperature for recycling is low, efficiency is low, and the gas barrier property is insufficient, and the content is reduced. And so on.

[0005] Therefore, the emergence of a polyester hollow molded article having more excellent heat resistance has been desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow molded article made of polyester having excellent heat resistance. Further, another object of the present invention is to provide a heat-resistant polyester resin suitable for uses such as beverage bottles and various containers.

[0007]

Means for Solving the Problems The present inventor has paid attention to such a problem, and has found that polyethylene terephthalate in which at least 80 mol% of the structural units is composed of ethylene terephthalate units is represented by the following formula (1):

[0008]

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Wherein R ₁ is a divalent aromatic organic group having 6 to 30 carbon atoms and which may contain a substituent;
₂ represents a divalent aromatic organic group having 6 to 30 carbon atoms, which may contain a substituent, an alkylene group having 2 to 20 carbon atoms, or a cycloalkylene group]. This is achieved by a polyester hollow molded article made of a resin composition consisting of:

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyethylene terephthalate of the present invention mainly comprises an ethylene terephthalate unit composed of terephthalic acid and ethylene glycol, and other components other than the terephthalic acid component and / or the ethylene glycol component constitute a total of 20 units. It may be contained as a copolymer component in an amount of mol% or less. Other acid components include, for example, other aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid Bifunctional carboxylic acids such as alicyclic dicarboxylic acids such as acids, aliphatic dicarboxylic acids such as adipic acid, sebacic acid and azelaic acid, and oxyacids such as p-β-hydroxyethoxybenzoic acid and ε-oxycaproic acid. Can be mentioned. These may be used alone or in combination.

Other glycol components include, for example, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol,
Other various substances such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2-bis (4′-β-hydroxyphenyl) propane, bis (4′-β-hydroxyethoxyphenyl) sulfonic acid, etc. Functional compounds can be mentioned. These may be combined.

The intrinsic viscosity of the polyethylene terephthalate used in the present invention, measured at 35 ° C. in a mixed solvent of tetrachloroethane: phenol = 4: 6, is preferably 0.6 to 1.3 dl / g. , More preferably 0.7-1.
2 dl / g.

The polyetherimide in the present invention is preferably amorphous from the viewpoint of solubility. However, even if crystalline polyetherimide is not crystallized when added to polyethylene terephthalate, it can be dissolved in the polyethylene terephthalate. Is very insoluble in polyethylene terephthalate. The term “amorphous” as used herein refers to a material that does not show a clear melting point peak as measured by a differential scanning calorimeter (DSC), and is generally a transparent resin.

The polyetherimide of the present invention has the following formula (1)

[0015]

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And a repeating unit represented by the formula: Here, R ₁ is a divalent aromatic organic group having 6 to 30 carbon atoms,
It may contain a substituent such as an alkyl group or an alkoxy group.
R ₂ is a divalent aromatic organic group having 6 to 30 carbon atoms, an alkylene group having 2 to 20 carbon atoms, or a cycloalkylene group, and may include a substituent such as an alkyl group or an alkoxy group. As R ₁ and R ₂ , polyethylene terephthalate
In terms of solubility with

[0017]

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The following can be mentioned. More preferably, R ₁ is

[0019]

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And R ₂ is the following formula:

[0021]

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Amorphous polyetherimide which is a group represented by the general formula “UL UL
It is commercially available under the trade name "TEM".

The molecular weight of the polyetherimide in the present invention is not particularly limited. When the addition amount of the polyetherimide is small, it may have a low molecular weight as long as the mechanical properties of the molded body are not impaired, but when the addition amount is large, it may be high molecular weight within a range that does not impair the moldability. Is preferred. In general, when the polyetherimide is soluble in a phenol / tetrachloroethane mixed solvent (weight ratio 60/40), the viscosity measured at 35 ° C. and a polymer concentration of 1.2 g / dl is 0.15 or more, preferably 0 or more. .25 or more is preferable.

In the present invention, the polyetherimide is mixed with polyethylene terephthalate after satisfying the above conditions to provide the resin composition comprising the above polyethylene terephthalate and polyetherimide in the present invention. .

It is preferable that the polyetherimide is mixed in an amount of 0.5 part by weight or more based on 100 parts by weight of the polyethylene terephthalate. When the amount is less than 0.5 part by weight, the improvement in heat resistance due to the addition of the polyetherimide is small. In particular, when the polyetherimide is blended to greatly improve the glass transition temperature of polyethylene terephthalate, it is more preferably added at least 1 part by weight, and even more preferably at least 5 parts by weight. The upper limit of the addition amount is not particularly defined unless there is a problem with the moldability, but generally the polyetherimide is used in an amount of 30.
If the amount exceeds the weight part, the moldability may be deteriorated due to the improvement of the melt viscosity, which may not be preferable. Therefore,
The addition amount of the polyetherimide is preferably 0.5 to 100 parts by weight of polyethylene terephthalate.
It is 30 parts by weight, more preferably 1 to 25 parts by weight. Further, in the present invention, when, for example, 10 parts by weight of the above-mentioned polyetherimide is added to 100 parts by weight of polyethylene terephthalate, the glass transition temperature of the polyethylene terephthalate before addition of the polyetherimide is improved by 5 ° C. or more. It is also preferable to use

The method for producing the resin composition of the present invention includes:
A mixing method using a twin-screw extruder is preferably used. The mixing temperature is within a range that does not cause polymer decomposition.
It is necessary to be higher than the melting point of polyethylene terephthalate. Mixing is substantially impossible below the melting point of polyethylene terephthalate. It is preferable that the temperature be equal to or higher than the glass transition temperature of the polyimide to be added. Generally, the mixing temperature is preferably 260 to 330 ° C,
280-290 ° C is more preferred.

Further, various additives can be further added to the resin composition of the present invention, if necessary. Such additives include glass fibers, metal fibers, aramid fibers, ceramic fibers, potassium whiskers, carbonated fibers, fibrous reinforcing agents such as asbestos,
Various fillers such as talc, calcium carbonate, mica, clay, titanium oxide, aluminum oxide, glass flakes, milled fiber, metal flakes, metal powders, and heat stabilizers represented by phosphates and phosphites Or oxidation stabilizer, light stabilizer, ultraviolet absorber,
Lubricants, pigments, flame retardants, flame retardant aids, plasticizers, crystal nucleating agents and the like can be mentioned.

According to the present invention, a resin composition comprising polyethylene terephthalate and polyetherimide and containing 0.5 to 30 parts by weight of polyetherimide based on 100 parts by weight of polyethylene terephthalate produces a hollow molded article. Provided for use as a material for.

The hollow molded article according to the present invention can be produced by a general molding method,
For example, injection blow molding, orientation blow, extrusion blow, and the like are applied. Although the polyester composition of the present invention depends on the molecular weight of the polyimide to be added, it generally has a higher melt viscosity than before the addition of polyetherimide, and is therefore suitable for blow molding. As a suitable example of the orientation blow method, a polymer is formed into an amorphous molded article on a hollow cylindrical bottom having a suitable shape (for example, 15 cm in length, 1 cm in inner diameter, 1.4 cm in outer diameter), and the glass transition of the polymer is carried out. The container is preheated to a point (Tg) or more, and the surface area of the container is stretched to about 1.5 to 16 times. The heat treatment of the container can be appropriately performed.

The polyester hollow molded article as described above has a body haze of 3% or less and an average density of the body of 1.34 to 1.34.
1.37 g / cm ³ and intrinsic viscosity of 0.6 to 1.0 dl
/ G.

The polyester hollow molded article according to the present invention can be used for various uses, and can be used as containers for juices, soft drinks, carbonated drinks, liquors, detergents, seasonings, oils, cosmetics, and the like. Moreover, after the used container is collected and washed, the contents can be refilled and reused.

[0032]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

(1) Intrinsic viscosity (IV): A polymer is dissolved in a mixed solvent of tetrachloroethane: phenol = 4: 6 so as to have a polymer concentration of 1.2 dl / g, and is heated at 35 ° C.
Was determined by measurement.

(2) Glass transition temperature (Tg): The temperature was raised at a rate of 20 ° C./min by a differential scanning calorimeter (DSC), and the melting point was +3.
After the temperature was raised to 0 ° C., for accuracy, the sample was taken out, rapidly cooled with dry ice, and then heated again at 20 ° C./min to determine the glass transition temperature.

(3) Heat resistance: The bottle obtained in Example was filled with hot water at 75 ° C., allowed to cool at room temperature, and the volume change before and after filling with hot water was measured. The mouth of the bottle was cut, immersed in hot water at 75 ° C. for 1 minute, and the change in the inner diameter of the mouth before and after the treatment was measured.

COMPARATIVE EXAMPLE 1 Polyethylene terephthalate (PET) having an intrinsic viscosity of 1.01 was obtained by using a 30 mmφ co-rotating twin-screw extruder (PCM30, manufactured by Ikegai Iron Works Co., Ltd.) at a polymer temperature of 285 ° C. and an average residence time. After melting for about 20 minutes, the material discharged from the discharge port of the twin screw extruder was quenched by cooling water, and cut into a chip having a diameter and length of about 3 mm with a cutter. Table 1 shows the glass transition temperature and melting point of the obtained chips. The chips were dried with hot air at 160 ° C. for 5 hours, and then injection-molded into a mold cooled with 10 ° C. cooling water using a M-100DM injection molding machine manufactured by Meiki Seisakusho at a cylinder setting of 275 ° C. I got a preform. This preform has an outer diameter of a cylindrical body of 22 to 24 mm, a thickness of 3.5 mm,
One end having a total length of 150 mm had a bottomed shape and was a substantially amorphous, colorless and transparent molded product.

This bottomed preform is heated at 100 to 130 ° C.
Stretch in the axial direction in the bottle-shaped mold at
g / cm ² , expanded laterally with nitrogen gas, with a body outer diameter of 82 mm, a total height of 280 mm, and an internal volume of 1450-1550.
ml bottles were molded. Next, the volume shrinkage and the inner diameter shrinkage of the manufactured bottle were measured, and the heat resistance was evaluated.

Example 1 A predetermined amount of ULTEM 1000 (hereinafter referred to as ULTEM, manufactured by General Electric Company) was added to PET having an intrinsic viscosity of 1.01, melt-kneaded as in the comparative example, formed into chips, and formed into a bottle. did. The performance of the obtained bottle is shown below. The amount of addition in the table indicates the weight percentage of ULTEM in the whole polymer. The glass transition temperature was improved, and the volume shrinkage and the inner diameter shrinkage were smaller than those in Comparative Example 1, and the heat resistance was significantly improved.

[0039]

[Table 1]

[0040]

The polyester hollow molded article obtained according to the present invention has extremely high heat resistance as compared with the conventional hollow molded article made of polyethylene terephthalate, and can be sufficiently sterilized and filled at high temperatures. In addition, it can be expected that the alkali cleaning temperature for circulation reuse can be increased and the efficiency can be increased.

Claims (4)

[Claims] 1. A polyethylene terephthalate in which at least 80 mol% of constituent units are composed of ethylene terephthalate units, and the following formula (1): [Wherein R ₁ is a divalent aromatic organic group having 6 to 30 carbon atoms and which may contain a substituent, and R ₂ has 6 to 30 carbon atoms.
30 represents a divalent aromatic organic group which may contain a substituent, an alkylene group having 2 to 20 carbon atoms, or a cycloalkylene group]. A hollow molded article made of polyester. 2. The polyester hollow molded article according to claim 1, wherein the content of the polyetherimide is in the range of 0.5 to 30 parts by weight based on 100 parts by weight of the resin composition. 3. R ₁ in the above formula (1) is represented by the following formula (2): And R ₂ is a group represented by the following formula (3): The polyester hollow molded article according to claim 1 or 2, which is a group represented by the formula: 4. Use of a resin composition comprising said polyethylene terephthalate and 0.5 to 30 parts by weight of said polyetherimide as a raw material for producing a hollow molded article (based on 100 parts by weight of said resin composition) And).