KR20100063423A - Polyethyleneterephthalate bottle with excellent dimension stability and thermostability, and process for preparing the same - Google Patents

Abstract

PURPOSE: A polyethylene terephthalate container with excellent dimension stability and thermostability and a manufacturing method thereof are provided, which can be used as a container for the hot filling usefully. CONSTITUTION: A manufacturing method of the polyethylene terephthalate container includes: a step of producing a preform by performing the injection-molding process to the polyethylene terephthalate resin in the condition of the barrel temperature 285-300°C, the block temperature of 285-300°C, the injection pressure of 900-1100bar, the switching position of 5-7mm, the pressure time of 10-15 sec, the back pressure of 10-30bar, the screw of 50-70rpm, and the molding temperature of 5-15°C; and a step of performing the blow molding process to the preform molded by injection in the condition of the blow delay time of 0.35-0.55sec, the first blow pressure of 11-15bar, the second blow pressure 30-50bar, the preform temperature of 95-120°C, and the heat fixed temperature of 150-180°C.

Description

Polyethyleneterephthalate bottle with excellent dimension stability and thermostability, and process for preparing the same}

The present invention relates to a polyethylene terephthalate container excellent in dimensional stability and heat resistance, and a method of manufacturing the same.

Polyethylene terephthalate resin is a resin produced by esterification (or transesterification), melt polymerization and solid state polymerization reaction using terephthalic acid as a dicarboxylic acid component and ethylene glycol as a dihydroxy component. Polyethylene terephthalate resin has excellent strength and transparency in itself, has a relatively high glass transition temperature (about 78 to 80 ° C.), and has a relatively good gas barrier property.

A general beverage container uses polyethylene terephthalate resin to produce an intermediate product preform through an injection process, and a polyethylene terephthalate container is produced through a blow process in which the preform is heated to a temperature of 90 to 110 ° C and blown into a bottle. Doing. The polyethylene terephthalate container is slightly different depending on the type of container depending on the production process. For example, polyethylene terephthalate containers used for beverages such as water, cola, cider, etc. do not require heat resistance because the beverage is filled at low temperature and not given heat during the filling process. However, the polyethylene terephthalate container used for juices, tea, coffee, sports drinks is filled with a beverage sterilized at a high temperature of more than 90 ℃ heat shrinkage phenomenon occurs due to the deformation of the product there is a problem that the product value is lowered. Therefore, such a polyethylene terephthalate container requires high heat resistance.

Many researchers have studied various methods to give high temperature resistance to polyethylene terephthalate containers.

Conventionally, in order to prevent thermal deformation of a polyethylene terephthalate container when a beverage having a glass transition temperature or more is filled into the polyethylene terephthalate container, the neck of the container is crystallized by a heat treatment process, and the temperature of the mold is blown to 120 to 180 ° C. The method of imparting heat stability to a polyethylene terephthalate container by holding and heat setting has been used. However, the heat-resistant polyethylene terephthalate container manufactured by the above method has a disadvantage in that the manufacturing cost is higher than that of a general container.

In addition to the above method, Japanese Patent Laid-Open No. 64-85732 discloses a method of preparing a heat resistant container by blending 65 to 98.5 mol% of polyethylene naphthalate terephthalate copolymer without whitening and heat treatment. No. 10-575126 describes a method for forming a heat resistant container of a copolymerized polyethylene naphthalate and polyethylene terephthalate blend. In addition, there is a method of manufacturing a heat-resistant container using a multilayer as a polyethylene terephthalate and a polyarylate resin, which is a high heat resistant resin, in processing. However, the above methods have been limited in their use because they require special and complicated treatments or other expensive resins having excellent heat resistance.

Until now, in order to minimize the deformation of the container by reducing the internal pressure when filling the polyethylene terephthalate container and cooling the content to room temperature, at least one groove is formed in the container body to concave toward the inside of the container to reduce the pressure. Heavy weight polyethylene terephthalate containers have been molded to form absorbent panel compartments and to ensure shape stability. However, in recent years, due to the explosion of raw materials and tightening environmental regulations, increasing interest in the environment, increasing the demand for lightweight containers has produced a polyethylene terephthalate container with a reduced thickness of the container. However, when producing a polyethylene terephthalate container having a reduced thickness by using a conventional pressure-sensitive panel, there are many difficulties in controlling the deformation of the container.

While the present inventors are working to control the deformation of the polyethylene terephthalate container whose thickness has been reduced due to the weight reduction, the present inventors have maintained the ratio of diameter (C) / height (D) of the pressure-reducing absorbing panel of the polyethylene terephthalate container in a certain range. , The distance E1 from the horizontal lip at the top of the vessel to the top of the panel or the distance E2 from the horizontal lip at the bottom of the vessel to the bottom of the panel is of a certain thickness, and the ratio of E1 or E2 and diameter (C) is in a certain range, The polyethylene terephthalate container was manufactured by molding the surface area of the panel to be 50% or more of the entire container. The polyethylene terephthalate container thus prepared was confirmed to have excellent dimensional stability and heat resistance, and thus, the present invention was completed.

The present invention is to provide a polyethylene terephthalate container excellent in dimensional stability and heat resistance, and a method of manufacturing the same despite the weight reduction.

The present invention maintains the diameter (C) / height (D) ratio of the pressure-sensitive absorption panel to 0.85 ~ 1.05, and the distance (E1) from the horizontal lip of the upper portion of the vessel to the top of the panel or the horizontal lip of the lower portion of the vessel to the bottom of the panel The distance (E2) of 11 to 15mm, the ratio of (E1 or E2) / diameter (C) is 0.1 to 0.5, the panel surface area of the polyethylene terephthalate, characterized in that 50 to 70% of the maximum total container Provide the container.

In addition, the present invention

1) For polyethylene terephthalate resin, barrel temperature 285 ~ 300 ℃, block temperature 285 ~ 300 ℃, injection pressure 900 ~ 1100bar, switching position 5 ~ 7㎜, holding time 10 ~ 15 sec, back pressure 10 ~ 30bar, screw 50 ~ 70rpm And producing preforms by injection molding under conditions of a mold temperature of 5 to 15 ° C., and

2) Blow the injection molded preform under the conditions of blow delay time 0.35 ~ 0.55sec, primary blow pressure 11 ~ 15bar, secondary blow pressure 30 ~ 50bar, preform temperature 95 ~ 120 ℃ and heat setting temperature 150 ~ 180 ℃ It provides a method for producing a polyethylene terephthalate container, comprising the step of performing the molding.

Hereinafter, the present invention will be described in detail.

The polyethylene terephthalate container according to the present invention maintains the diameter (C) / height (D) ratio of the pressure-sensitive absorption panel at 0.85 to 1.05, and the distance (E1) from the horizontal lip at the top of the container to the top of the panel or at the bottom of the container. The distance (E2) from the horizontal lip to the bottom of the panel is 11-15 mm, the ratio of (E1 or E2) / diameter (C) is 0.1-0.5, and the surface area of the panel is 50-70% of the maximum overall container. It features.

If the ratio of diameter (C) / height (D) of the pressure-reduction absorbing panel is less than 0.85, the internal pressure is also not improved due to the high temperature of the container. Thus, when the container is filled with hot drinks, shrinkage of the container occurs, and the ratio is 1.05. If it exceeds, the shape of the container may be deformed into an oval shape by cooling negative pressure due to the expansion of the straight section of the container design.

In addition, the distance E1 from the horizontal lip at the top of the vessel to the top of the panel or the distance E2 from the horizontal lip at the bottom of the vessel to the bottom of the panel, and the ratio of (E1 or E2) / diameter (C) are in this range. Deviation will result in thermal strain on hot charge and negative pressure when the vessel is cooled.

In order to have the properties required for deformation and mechanical strength of the polyethylene terephthalate container according to the present invention, the thickness of the wall forming the body of the container is preferably 30 to 100 µm, preferably 50 to 70 µm. Thin areas or portions of the wall forming the body of the container can be provided near the body of the container, especially near the neck and bottom, thereby partially reinforcing these parts. Hardening of the neck may be particularly useful to facilitate filling of high temperature contents (above 90 ° C.) or to increase storage stability, and there may be panels in the body of the container to prevent deformation of the container.

Polyethylene terephthalate container according to the present invention is excellent in dimensional stability and heat resistance because the volume shrinkage rate is 6% or less when filling hot water of 90 ℃ or more despite the weight reduction. Therefore, the polyethylene terephthalate container according to the present invention can be usefully used as a container for high temperature filling.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited by the examples.

Examples 1-6 and Comparative Examples 1-3  : Manufacture of polyethylene terephthalate container

Hot air-dried the usual polyethylene terephthalate resin having an intrinsic viscosity of 0.8 mW / g at 160 ° C., barrel temperature 295 ° C., block temperature 295 ° C., injection pressure 1000 bar, switching position 6 mm, holding time 13 sec, back pressure 20 bar, screw Injection molding was carried out under the condition of 60 rpm and mold temperature of 10 ℃ to produce a preform. The injection molded preforms were blow molded under conditions of a blow delay time of 0.45 sec, a primary blow pressure of 13 bar, a secondary blow pressure of 40 bar, a preform temperature of 110 ° C, and a heat setting temperature of 160 ° C. The total surface area of the container thus manufactured, the surface area of the entire pressure-reducing absorbing panel, the height (D) and diameter (C) of the pressure-reducing absorbing panel, the distance from the horizontal lip at the top of the vessel to the top of the panel (E1) or the horizontal lip at the bottom of the vessel The distance E2 to the bottom of the panel, and the surface area of the panel are shown in Table 1 below. A front view of the polyethylene terephthalate container according to the present invention is shown in FIG. 1.

Example Comparative example One 2 3 4 5 6 One 2 3 Total surface area of the container (cm 2) 435.2 435.2 435.2 435.2 435.2 435.2 435.2 435.2 435.2 Surface area of the entire reduced pressure absorption panel (㎠) 218.0 218.0 261.0 283.0 226.3 218.0 196.0 218.0 235.0 Height of the reduced pressure absorption panel (D, mm) 75.78 71.61 75.78 75.78 68.20 75.78 75.78 85.25 85.25 Diameter of reduced pressure absorption panel (C, ㎜) 68.20 68.20 68.20 68.20 68.20 68.20 68.20 68.20 68.20 Diameter / Height Ratio (C / D, ㎜) of Pressure Sensitive Absorption Panel 0.90 0.95 0.90 0.90 1.0 0.90 0.90 0.80 0.80 E1 or E2 (mm) 12 12 12 12 12 12 12 12 12 (E1 or E2) / C ratio 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 Panel area (%) 50.1 50.1 60 65 52 50.1 45 50.1 54

Experimental Example 1  : Measurement of physical properties of polyethylene terephthalate container

In order to check the physical properties of the polyethylene terephthalate container according to the present invention, the following experiment was performed.

1. Heat resistance and volume shrinkage

The height, weight, 20 ° C. F.P.V (Fill Point Volume) and dimensions of the polyethylene terephthalate containers prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were measured. Then, the polyethylene terephthalate container was visually observed for deformation of the container after a hot filling test. That is, hot water at a specific temperature was charged in the polyethylene terephthalate container and maintained for 5 minutes, and then cooled with 10 ° C. cooling water, and then visually observed whether the container was deformed. The volumetric shrinkage, height, weight, 20 ° C. F.P.V and dimensions of the polyethylene terephthalate vessel were then measured.

2. Vacuum degree

The polyethylene terephthalate containers prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were measured using a cap with a pressure gauge to measure the reduced pressure inside the container in a cooling state after a high temperature charging experiment.

The measurement results of the heat resistance, vacuum degree and volume shrinkage rate of the polyethylene terephthalate container of the present invention are shown in Table 2.

Heat resistance degree (℃) Vacuum degree (mmHg) Volume Shrinkage (%) Example 1 93 120 5.6 Example 2 92 125 5.7 Example 3 94 120 5.6 Example 4 92 123 5.5 Example 5 93 121 5.7 Example 6 93 123 5.2 Comparative Example 1 88 220 9.0 Comparative Example 2 83 234 9.2 Comparative Example 3 89 200 9.3

As shown in Table 2, despite the weight reduction, the polyethylene terephthalate container according to the present invention exhibits excellent dimensional stability and heat resistance as the volume shrinkage rate is 6% or less when filled with hot water of 90 ° C. or higher.

Therefore, the polyethylene terephthalate container according to the present invention can be usefully used as a container for high temperature filling.

Polyethylene terephthalate container according to the present invention is excellent in dimensional stability and heat resistance because the volume shrinkage rate is 6% or less when filling hot water of 90 ℃ or more despite the weight reduction. Therefore, the polyethylene terephthalate container according to the present invention can be usefully used as a container for high temperature filling.

1 is a front view showing a polyethylene terephthalate container according to the present invention.

Claims (3)

Maintain the ratio (C) / height (D) of the pressure-sensitive absorption panel at 0.85 to 1.05, and the distance from the horizontal lip at the top of the vessel to the top of the panel (E1) or the distance from the horizontal lip at the bottom of the vessel to the bottom of the panel ( E2) is 11-15 mm, the ratio of (E1 or E2) / diameter (C) is 0.1-0.5, The surface area of a panel is 50 to 70% of the maximum total container, The polyethylene terephthalate container characterized by the above-mentioned. The polyethylene terephthalate container according to claim 1, wherein the wall forming the body of the container has a thickness of 30 to 100 μm. 1) For polyethylene terephthalate resin, barrel temperature 285 ~ 300 ℃, block temperature 285 ~ 300 ℃, injection pressure 900 ~ 1100bar, switching position 5 ~ 7㎜, holding time 10 ~ 15 sec, back pressure 10 ~ 30bar, screw 50 ~ 70rpm And producing preforms by injection molding under conditions of a mold temperature of 5 to 15 ° C., and 2) Blow the injection molded preform under the conditions of blow delay time 0.35 ~ 0.55sec, primary blow pressure 11 ~ 15bar, secondary blow pressure 30 ~ 50bar, preform temperature 95 ~ 120 ℃ and heat setting temperature 150 ~ 180 ℃ A method for producing the polyethylene terephthalate container of claim 1, comprising performing molding.

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