JPH08323844A - Polyester hollow container - Google Patents

Abstract

PURPOSE: To provide a polyester hollow container excellent in ultraviolet shading properties and transparency and easily susceptible of direct blow molding. CONSTITUTION: An extrusion blow molded hollow container is obtained by molding a polyester resin composed of a polyester copolymer containing 92-99mol% of a terephthalic acid component and 1-8mol% of a 2,6- naphthalenedicarboxylic acid component as acid components and ethylene glycol as a main alcohol component and having intrinsic viscosity of 0.9-1.2dl/g.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an extrusion blow-molded hollow container made of a specific copolymerized polyester. More specifically, cosmetics with excellent UV blocking properties and transparency,
The present invention relates to an extrusion blow-molded hollow container useful as a container for detergents, foods, beverages and the like.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter PE
A hollow container obtained by melt-molding a resin (denoted as T) can be easily molded, and has excellent transparency and mechanical properties.
Furthermore, there is little concern about residual monomers and harmful additives such as in vinyl chloride resin hollow containers, and from the aspects of hygiene and safety, foods such as seasonings, edible oils, alcoholic beverages, carbonated beverages, fruit juice-containing beverages, mineral water, etc. In recent years, it has been widely used for applications and non-food applications such as detergents and cosmetics.

The direct blow molding method (extrusion blow method) is currently generally used in the manufacture of plastic hollow containers in terms of ease of molding, productivity, and low equipment cost. A feature of the direct blow molding method is that the resin used must have a high melt viscosity to prevent drawdown of the parison extruded in the molten state during blow molding. And polyolefins are used.

As described above, PET resin has characteristics superior to vinyl chloride resin and polyolefin in terms of transparency, safety, hygiene, etc., and although it is extremely suitable as a material for various hollow containers, it is generally used. It was difficult to manufacture a hollow container by direct blow molding because it does not have a high melt viscosity suitable for direct blow molding.

In addition, since the hollow container made of PET resin does not have sufficient ultraviolet ray shielding property depending on the application, the content is discolored by the irradiation of ultraviolet ray from the outside to lower the commercial value or to deteriorate the taste. There is a problem that is dropped.

As a method for solving such a problem, it has been studied to add an organic or inorganic ultraviolet absorber to the PET resin, but the toxicity of the ultraviolet absorber and the odor caused by elution into the contents may be reduced. There is a problem with the change in taste.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a polyester hollow container which is excellent in ultraviolet ray blocking property and transparency and can be easily subjected to direct blow molding.

[0008]

The above object is to use 92 to 99 mol% of a terephthalic acid component and 1 to 8 mol% of a 2,6-naphthalenedicarboxylic acid component as an acid component, and ethylene glycol as a main alcohol component. Made of polyester copolymer and has an intrinsic viscosity of 0.9-1.2 dl
It is achieved by an extrusion blow-molded hollow container, which is obtained by molding a polyester resin having an amount of / g.

2, contained in the polyester resin of the present invention
The 6-naphthalenedicarboxylic acid component is 1 to 8 mol% based on the total dicarboxylic acid component as 100. When it is less than 1 mol%, the UV blocking property is not sufficient, and 8 mol%
When the amount is larger, crystallization does not proceed, and when a high-viscosity resin suitable for extrusion blow molding is produced by solid-state polymerization, fusion between the resins occurs and the productivity is significantly reduced.

The main diol component of the polyester resin of the present invention is ethylene glycol, but other components include diethylene glycol, triethylene glycol,
Tetraethylene glycol, polyethylene glycol,
The content of 1,4-cyclohexanedimethanol may be 5 mol% or less based on 100 of all diol components.

The polyester hollow container of the present invention can be manufactured as follows. First, a low polymer is prepared by directly esterifying the above-mentioned dicarboxylic acid component and diol component according to a conventional method or transesterifying in the presence of an organic acid calcium salt.

Next, using germanium oxide and / or antimony oxide as a polycondensation catalyst, the pressure is reduced to 250 ° C.
Polycondensation reaction is performed at ˜300 ° C. to produce a polyester resin having a desired viscosity. Further, a polyester resin copolymer having a high degree of polymerization is produced by solid phase polymerization.

The intrinsic viscosity of the polyester resin of the present invention is 0.9 to 1.2 dl / g. If it is less than 0.9 dl / g, the melt flow rate of the polyester resin at 280 ° C (direct blow molding temperature) is 10.0 g / 10 mi.
It becomes higher than n, and a high melt viscosity suitable for direct blow molding cannot be obtained. Further, the production of a polyester resin exceeding 1.2 dl / g requires solid phase polymerization for a long time, which is not preferable because of high cost.

The melt flow rate of the polyester resin described in the present invention means that the polyester resin has an inner diameter of 9.55.
mm, length 162 mm, filled in a cylinder, the resin in the cylinder was melted at 280 ℃, the weight of 2160 g,
2.1mm diameter provided in the center of the cylinder when a plunger with a diameter of 9.48mm is placed and evenly loaded.
The measured value is the weight velocity (g / 10 min) of the molten polymer extruded from the orifice.

The above polyester copolymer is mixed with water of 100 pp.
After drying to m or less, preferably 50 ppm or less, extruding through a die orifice, molding into a cylindrical parison (preform), sandwiching this with a mold and blowing air inside to mold a polyester hollow container You can

[0016]

The polyester hollow container of the present invention has excellent direct blow moldability and transparency, and has a thickness of 360 nm.
It has the property of blocking all of the following ultraviolet rays.

[0017]

The present invention will be described in more detail with reference to the following examples. The intrinsic viscosity of the polyester copolymer, the molar ratio of the copolymerization components, the melt flow rate, and the UV blocking property of the molding bottle in the examples were measured by the following methods. (1) Intrinsic viscosity 0.5 g of a sample was dissolved in 50 ml of a mixed solution of 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane, and measured at 20 ° C. (2) Molar ratio of copolymerization component By using FT-NMR (300MG type manufactured by Varian),
Mixed solution of trifluoroacetic acid and chloroform (1: 1)
The sample was dissolved in, mixed with tetramethylsilane as a standard, and the proton NMR spectrum was measured. (3) Melt Flow Rate (MFR) A melt indexer (manufactured by Toyo Seiki Seisakusho) was used, and measurement was performed at a resin melting temperature of 280 ° C. according to JIS-K7210. (4) UV blocking property A UV absorption curve was measured using a spectrophotometer (manufactured by Hitachi, Ltd.).

Example 1 23.04 kg of dimethyl terephthalate, 1.53 kg of dimethyl 2,6-naphthalenedicarboxylate, 17.05 kg of ethylene glycol, 22.64 g of calcium acetate as a transesterification catalyst, and a polymerization vessel having a rectification column. Then, the mixture was heated to 250 ° C. and stirred while flowing a slight amount of nitrogen. During this period, the rectification column temperature was maintained at 60 ° C to 70 ° C to reflux ethylene glycol and distill only methanol out of the system.

When the transesterification rate reached to about 90% as calculated from the amount of collected methanol, 3.75 g of germanium oxide as a polymerization catalyst and 2.08 g of trimethyl phosphate as a heat stabilizer were added. The pressure was gradually reduced while continuing heating and stirring, and the inside of the can was set to a high vacuum of 1 torr or less over about 1 hour. During this time, the temperature was raised to 280 ° C. After continuing the polymerization for about 3 hours in this state, the pressure was returned to normal pressure and the polymer was extruded. The intrinsic viscosity at this time was 0.53. The extruded pellets were pre-crystallized at 130 ° C. for 2 hours and then solid-state polymerized at 215 ° C. for 20 hours in a nitrogen stream to obtain a polymer having an intrinsic viscosity of 1.05.

The molar ratio of the 2.6-naphthalenedicarboxylic acid component contained in the obtained polymer and the MF of the polymer.
The R value was measured. The results are shown in Table 1.

This polyester resin was dried under reduced pressure at 130 ° C. to a water content of 100 ppm or less, and molded into a hollow container having a polymer temperature of 280 ° C., a polymer volume of 500 ml, a basis weight of 20 g and a cap diameter of 20 mm using a direct blow molding machine.

An ultraviolet absorption curve obtained by cutting and measuring the body of the container is shown in the graph of FIG.

Example 2 In Example 1, dimethyl terephthalate 22.67 k
g, dimethyl 2,6-naphthalenedicarboxylate 2.48k
An experiment was conducted under the same conditions as in Example 1 except that g was used.
The results are shown in Table 1 and FIG.

Example 3 In Example 1, dimethyl terephthalate 23.52k
g, Dimethyl 2,6-naphthalenedicarboxylate 0.92k
An experiment was conducted under the same conditions as in Example 1 except that g was used.
The results are shown in Table 1 and FIG.

Comparative Example 1 In Example 1, dimethyl terephthalate 24.13 k
g, Dimethyl 2,6-naphthalenedicarboxylate 0.15k
An experiment was conducted under the same conditions as in Example 1 except that g was used.
The results are shown in Table 1 and FIG.

Comparative Example 2 In Example 1, dimethyl terephthalate 21.83 k
g, dimethyl 2,6-naphthalenedicarboxylate 3.05k
An experiment was conducted under the same conditions as in Example 1 except that g was used.
Although the solid phase polymerization rate was slow and solid phase polymerization was carried out for 40 hours, the intrinsic viscosity of the obtained polymer was 0.84. This polyester resin was dried under reduced pressure to a water content of 100 ppm or less at 130 ° C., and a direct blow molding machine was used to form a hollow container having a polymer temperature of 280 ° C., an internal capacity of 500 ml, a basis weight of 20 g, and a cap diameter of 20 mm. A normal bottle with a large down was not obtained.

[0027]

[Table 1]

[Brief description of drawings]

FIG. 1 is an explanatory view showing an ultraviolet absorption curve of a resin container of the present invention.

Claims (1)

[Claims] 1. A polyester comprising terephthalic acid component 92 to 99 mol% and 2,6-naphthalenedicarboxylic acid component 1 to 8 mol% as an acid component and ethylene glycol as a main diol component and having an intrinsic viscosity of 0. .9
An extrusion blow-molded hollow container obtained by molding a polyester resin having a content of 1.2 dl / g.