JPH1086213A - Preform for bottle and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preform for bottle, made of resin, having ultraviolet barrier property and heat resistance, excellent transparency, only a little acetaldehyde content, and excellent smell and taste. SOLUTION: A preform is formed by melting and mixing 5-95 pts.wt. of thermoplastic polyester (A) whose main repeat unit is of ethylene terephthalate and 95-5 pts.wt. of thermoplastic polyester (B) whose main repeat unit is of ethylene naphthalene dicarboxylate. The haze value is set to 3% or less and the acetaldehyde content is set to 10ppm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preform for a bottle comprising a thermoplastic polyester resin composition, having excellent transparency, containing a small amount of acetaldehyde, and having excellent ultraviolet shielding properties.

[0002]

2. Description of the Related Art Glass is widely used as a material for containers for seasonings, oils, juices, carbonated drinks, beer, sake, cosmetics, detergents and the like. Since glass is expensive to manufacture, it is common practice to collect and recycle the used containers, but glass containers are liable to breakage and are inconvenient to handle.

[0003] In order to solve these problems, conversion from glass containers to plastic containers is progressing. Among the materials used for plastic containers, polyethylene terephthalate has excellent mechanical strength, heat resistance, transparency and gas barrier properties, so it can be used in containers for juices, soft drinks, carbonated drinks, seasonings, detergents, cosmetics, etc. Used as a material.

[0004] However, the polyethylene terephthalate container has a problem in that the contents are deteriorated by the irradiation of ultraviolet rays from the outside such as sunlight and electric lamps because the ultraviolet ray blocking ability is not sufficient. This problem is manifested, for example, as deterioration in taste when the contents are food and drink, and as fading of the product when the contents are cosmetics, resulting in a decrease in commercial value.
Further, the polyethylene terephthalate container has problems such as insufficient sterilization and high-temperature filling due to insufficient heat resistance.

[0005]

It is known that these problems can be solved by using a composition comprising polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate in a container. However, simply blending polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate to produce a bottle or bottle preform will have problems in various respects in the resulting bottle or preform. That is, there is a problem that odor and taste are inferior due to low transparency and a large amount of acetaldehyde contained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a preform for a resin bolt having ultraviolet blocking properties and heat resistance, which is excellent in transparency, contains a small amount of acetaldehyde, and is excellent in odor and taste. Is to do.

[0007]

That is, the present invention relates to a thermoplastic polyester (A) in which the main repeating unit is ethylene terephthalate (5 to 95 parts by weight) and a thermoplastic polyester (B) in which the main repeating unit is ethylene naphthalenedicarboxylate. And 95 to 5 parts by weight of a preform for a bottle having a haze value of 3% or less and an acetaldehyde content of 10 ppm or less and a method for producing the same.

The thermoplastic polyester (A) having ethylene terephthalate as a main repeating unit according to the present invention.
Is mainly intended to be a homopolymer of ethylene terephthalate having terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component, but other dicarboxylic acid components and / or other diol components as one copolymer component.
It may be copolymerized in a range of 0 mol% or less. In the copolymerization component, as a dicarboxylic acid component, for example, an aromatic dicarboxylic acid such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfondicarboxylic acid, etc .; hexahydroterephthalic acid, hexa Alicyclic dicarboxylic acids such as hydroisophthalic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid and azelaic acid; difunctional acids such as oxyacids such as p-β-hydroxyethoxybenzoic acid and ε-oxycaproic acid The diol component includes, for example, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol, 1,1- Cyclohexane dimethanol, 1,4-cyclohexane dimethanol, 2,2-bis (4 'over β
-Hydroxyphenyl) propane, bis (4'-β-hydroxyethoxyphenyl) sulfonic acid, and the like.

A thermoplastic polyester (B) whose main repeating unit is ethylene naphthalenedicarboxylate
Is mainly intended for homopolymers of polyethylene-2,6-naphthalenedicarboxylate, wherein other dicarboxylic acid components and / or other diol components are copolymerized in a range of 20 mol% or less as a copolymer component. You may.
The copolymerization component is a dicarboxylic acid component. The above-mentioned dicarboxylic acid component, 6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,7 Naphthalenedicarboxylic acid, other isomers of naphthalenedicarboxylic acid, terephthalic acid can be used, and polyfunctional glycol can be used as a diol component.

[0010] The preform for bolts of the present invention has a haze value of 3% or less. If the haze exceeds 3%, the transparency when formed into a bolt is inferior, and the appearance as a transparent packaging container is impaired.

The preform for bottles of the present invention has an acetaldehyde content of 10 ppm or less. If the content of acetaldehyde exceeds 10 ppm, there are problems such as generation of odor after bottle molding and bad taste after filling with carbonated water.

The preform for bottles of the present invention has good ultraviolet blocking properties. Thermoplastic polyester 5 whose main repeating unit is ethylene naphthalenedicarboxylate
If the amount is less than the weight part, the ultraviolet ray blocking property cannot be sufficiently exhibited.

The present invention provides a preform for a bolt made of resin having ultraviolet shielding properties and heat resistance, which is excellent in transparency, contains a small amount of acetaldehyde, and is excellent in odor and taste. It is.

In the present invention, the preform for bolts is produced by melt-kneading a composition of polyester (A) and polyester (B) under specific conditions and molding.

The preform for a bolt is an amorphous hollow molded product, and is generally a molded product having a hollow cylindrical bottomed shape. The preform for a bottle is generally used by being formed into a bottle by blow molding or the like. The bottle preform is, for example, generally a hollow shape having a length of 15 cm, an inner diameter of 1 cm, and an outer diameter of 1.4 cm.

The molding temperature at the time of preform molding is set at a temperature lower than the temperature at which the composition starts to thermally decompose, and the temperature is 260 to 300 ° C., preferably 270.
Performed at a temperature of 290 ° C. Further, at the time of melt kneading, the pressure is reduced to a degree of vacuum of 5 Torr or less from a vacuum vent. The residence time during molding is from several tens of seconds to several tens of minutes, preferably 1
Minutes to 5 minutes.

The preform of the present invention is molded into a bottle by a general molding method. For example, injection blow molding, oriented blow molding, and extrusion blow molding are applied. As a suitable example of the orientation blow molding, the formed preform is preheated to a temperature higher than the glass transition point (Tg) of the polymer, and the surface area of the container is stretched to about 4 to 16 times. Note that the heat treatment of the container can be appropriately performed. The molded bottle is excellent in transparency, contains a small amount of acetaldehyde, and has good ultraviolet blocking properties.

Thus, the preform of the present invention produced by the above-described method is excellent in transparency and contains a small amount of acetaldehyde, so that it can be used for various uses. For example, seasonings, oils, alcoholic beverages, cosmetics It can be used by molding into containers for detergents, soft drinks, carbonated drinks and juices.

[0019]

The present invention will be described below in detail with reference to examples. The main measurement conditions of the physical properties are as follows. (1) Intrinsic viscosity (IV): Measured at 35 ° C. as a mixed solvent of tetrachloroethane: phenol = 4: 6. (2) Haze: Measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd. (3) Acetaldehyde amount: The sample was frozen and pulverized with liquid nitrogen and then measured by gas chromatography. (4) Ultraviolet ray blocking property: Measured with Hitachi's self-recording spectrophotometer type 320.

Examples 1 to 3 PET of IV 0.83
And 0.55 PEN chips were each dried with hot air at 160 ° C. for 5 hours, and then using an injection molding machine with a vacuum vent,
The cylinder was set at 275 ° C., the degree of vacuum at the vent port was 5 Torr or less, and injection molding was performed in a mold cooled with cooling water at 10 ° C. to obtain a preform. This preform has an outer diameter of a cylindrical body of 22 to 24 mm, a thickness of 3.5 mm, and a total length of 1
One end of 50 mm had a bottomed shape, and was a substantially amorphous, colorless and transparent molded body. Table 1 shows the haze of the obtained preform, the amount of acetaldehyde contained therein, the ultraviolet shielding property, the odor of the bottle, and the taste test result after filling with carbonated water.

[Comparative Examples 1 to 3] Using a PET having an IV of 0.83 and a PEN chip having an IV of 0.56, each was dried with hot air at 160 ° C. for 5 hours. A preform was obtained by injection molding in a mold cooled with cooling water at 10 ° C. under pressure. This preform has a cylindrical body having an outer diameter of 22 to 24 mm, a wall thickness of 3.5 mm, and a total length of 150 mm, and has one end with a bottom. there were. Table 1 shows the haze, the amount of acetaldehyde contained, and the ultraviolet shielding property of the obtained preform. Table 1 shows the odor of the bottle obtained by molding the preform and the taste test result after filling with carbonated water.

[0022]

[Table 1]

[0023]

According to the present invention, it is possible to obtain a preform having good transparency, containing a small amount of acetaldehyde, and having excellent ultraviolet blocking properties. Further, the bottle using this preform has a low odor and a good taste after filling with carbonated water.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B29K 67:00 B29L 22:00

Claims (2)

[Claims] 1. Melting of 5 to 95 parts by weight of a thermoplastic polyester (A) whose main repeating unit is ethylene terephthalate and 95 to 5 parts by weight of a thermoplastic polyester (B) whose main repeating unit is ethylene naphthalene dicarboxylate A preform for bottles which is formed by mixing and has a haze value of 3% or less and an acetaldehyde content of 10 ppm or less. 2. The degree of vacuum in the mixing system during melt mixing is 5 To
2. The method for producing a preform for a bottle according to claim 1, wherein the rr is not more than rr.