JPH0577310A - Bottle made of polyethylene terephthalate resin and preparation thereof - Google Patents

Abstract

PURPOSE:To provide a bottle made of polyethylene terephthalate resin having an opening which is not thermally deformed by heating due to thermal filling of the content and exhibits excellent heat resistance and a method for efficiently preparing it. CONSTITUTION:The title bottle is a bottle made of polyethylene terephthalate (PET) resin constituted of a bottle main body consisting of a biaxially oriented PET resin and an opening 3 provided above the bottle main body and consisting of an unoriented PET resin and the inner face side of the opening 3 is a region whitened by crystallization. This bottle made of PET resin is efficiently prepd. by heating the boundary of the opening 3 of a preform and the primary molding 2a of the bottle and successively heating the inner face side of the opening 3 in the temp. adjusting process for blow molding of the preform by using a heating body assisting heating in the neighborhood of the boundary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mouth portion of a bottle made of polyethylene terephthalate resin, and more particularly to improvement of its heat resistance.

[0002]

2. Description of the Related Art Conventionally, a bottle made of polyethylene terephthalate resin, whose bottle body is biaxially stretch blow molded, has been widely used. This type of bottle is excellent in transparency, impact resistance, gas barrier property, and lightness because the polyethylene terephthalate resin forming the bottle body is molecularly oriented by biaxial stretching.

On the other hand, since the mouth of the bottle is made of polyethylene terephthalate resin which has not been stretched, it cannot be said that the heat resistance is sufficient, and there is a possibility that the bottle may be deformed by heating when the contents are filled with heat. is there. When the mouth is deformed,
There is an inconvenience that the sealing property between the mouth portion and the cap becomes insufficient and the contents leak.

In order to solve the above problem, Japanese Patent Publication No. 61-
No. 35056 discloses a bottle made of polyethylene terephthalate resin in which the bottle body is biaxially stretch blow molded and the unstretched mouth is whitened and crystallized. According to the bottle made of polyethylene terephthalate resin disclosed in the above-mentioned publication, its mouth portion is unstretched, but since it is whitened and crystallized, it is heat-deformed by heat of the contents filled with heat to improve its heat resistance. It is said that the sealing property between the mouth portion and the cap is kept good and the contents do not leak.

The whitening and crystallization of the unstretched polyethylene terephthalate resin is carried out, for example, by arranging a shielding plate just under the mouth so that the area below the mouth is not heated and the mouth is heated by radiant heat from a heater or the like. The method is performed by covering the mouth portion with a metal cap, applying radiant heat to the metal cap, or by induction heating the metal cap through an electrode arranged outside the metal cap.

However, according to the study by the present inventors, in the bottle whose white portion is whitened and crystallized by the above-mentioned method, the inner surface side is not sufficiently whitened and crystallized because the outer surface side of the mouth portion is heated. It was found that sufficient heat resistance may not be obtained. According to the study of the present inventors, thermal deformation of the mouth portion due to heating occurs on the inner surface side of the mouth portion, and in order to prevent this thermal deformation, unstretched polyethylene terephthalate resin is sufficient on the inner surface side of the mouth portion. It must be whitened and crystallized.

However, in the above-mentioned method, since heating is performed from the outer surface side of the mouth portion, the heating time must be extended in order to fully whiten and crystallize to the inner surface side of the mouth portion, and a decrease in manufacturing efficiency is avoided. I can't.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves such inconveniences, and a bottle made of polyethylene terephthalate resin having a mouth portion excellent in heat resistance which is not thermally deformed by the heat of the contents filled with heat, and It is an object to provide an efficient manufacturing method thereof.

[0009]

In order to achieve the above object, a bottle of polyethylene terephthalate resin according to the present invention comprises a bottle body that is biaxially stretched, and a non-stretched mouth provided above the bottle body. A bottle made of polyethylene terephthalate resin having a thread forming portion on the outer periphery of the mouth portion, the mouth portion is provided integrally with the bottle body, and the inner surface side of the mouth portion is whitened crystal. It is characterized by having become.

The bottle body made of polyethylene terephthalate resin of the present invention is formed by injecting a molten polyethylene terephthalate resin into a mold having a predetermined shape to form a mouth portion having a screw forming portion and a cylindrical bottle body with a bottom. An injection molding step of molding a bottle preform composed of a molded body, and the bottle preform obtained in the injection molding step is heated in a state in which the mouth outer peripheral portion is clamped by a mold, The temperature control step of adjusting the temperature of the primary molded body to a temperature suitable for blow molding, and the primary molded body of the bottle main body adjusted to the temperature suitable for blow molding in the temperature control step are formed into the shape of the blow molding mold. A polyethylene terephthalate resin comprising a blow molding step of forming a bottle main body by blow molding along the same and a demolding step of separating the bottle body obtained in the blow molding step from the blow molding die. In the method for manufacturing a bottle-manufacturing body, in the temperature controlling step, the primary molded body of the bottle main body is inserted into a temperature controller with the outer peripheral portion of the mouth portion being sandwiched by a mold, and the primary molded body is heated from the outer surface side. Together with the heating method, the heating body is inserted into the inner surface side of the primary molded body to heat the vicinity of the boundary between the mouth portion and the primary molded body, and then the heating member heats the inner surface side of the mouth portion. , Can be advantageously manufactured.

[0011]

According to the bottle body made of polyethylene terephthalate resin of the present invention, the mouth portion integrally formed with the bottle body is formed of unstretched polyethylene terephthalate resin, but the inner surface side is whitened. Has been crystallized,
It is a crystallized polyethylene terephthalate resin. The unstretched polyethylene terephthalate resin is modified by being whitened and crystallized, and has improved heat resistance.

According to the bottle of the present invention, since the inner surface side of the mouth portion is made of the whitened and crystallized polyethylene terephthalate resin having excellent heat resistance as described above, even if the contents are filled with heat, Thermal deformation of the mouth due to heat is avoided.

Therefore, according to the bottle of the present invention, the sealing property between the mouth portion and the cap is maintained well, and the leakage of the contents is prevented. Further, according to the bottle of the present invention, since only the inner surface side of the mouth is whitened and crystallized, the mouth surface has gloss, and it is observed integrally with the bottle body which is transparent from the appearance,
It is not necessary to give the impression that the mouth is composed of another member.

Further, according to the method for producing a polyethylene terephthalate resin bottle body of the present invention, in the temperature control step of adjusting the temperature of the preform obtained in the injection molding step for blow molding, the inner surface side of the mouth part Is heated for whitening and crystallization.

In the temperature control step, the bottle preform is in a state where the primary molded body of the bottle main body is inserted into the temperature control device and heated from the outer surface side, but the outer peripheral portion of the mouth is clamped by the mold. Therefore, the mouth portion is cooled by the mold, and heating near the boundary between the mouth portion and the primary molded body tends to be insufficient. Therefore, a heating body is inserted on the inner surface side of the primary molded body to assist heating near the boundary between the mouth portion and the primary molded body.

In the manufacturing method of the present invention, after the heating of the vicinity of the boundary between the mouth portion and the primary molded body by the heating body is completed,
Subsequently, the heating element is moved upward to heat the mouth portion from the inner surface side. Therefore, the polyethylene terephthalate resin on the inner surface side of the mouth is surely whitened and crystallized, and only the practically sufficient range on the inner surface side of the mouth is whitened and crystallized, so that efficient heating is performed. Further, at this time, since the outer peripheral side of the mouth portion is sandwiched by the mold and cooled, it is possible to avoid the deformation of the screw forming portion due to heating for whitening and crystallization.

[0017]

EXAMPLE FIG. 1 is a front view showing an example of a polyethylene terephthalate resin bottle according to the present embodiment, FIG. 2 is an explanatory sectional view of the mouth of the polyethylene terephthalate resin bottle shown in FIG. 1, and FIGS. 6 is an explanatory sectional view showing an injection molding process in the manufacturing method of this embodiment.

As shown in FIG. 1, a polyethylene terephthalate resin bottle body 1 of this embodiment comprises a bottle body 2 and a mouth portion 3 provided above the bottle body 2, and the mouth portion 3 has an outer periphery. The screw forming portion 4 is included in the portion. In the bottle body 1 made of polyethylene terephthalate resin of this embodiment, the bottle body 2 is made of polyethylene terephthalate resin which is biaxially stretched, and the mouth portion 3 is made of unstretched polyethylene terephthalate resin.

As shown in FIG. 2, the inner surface side of the mouth portion 3 is a whitened and crystallized region 5. In the present invention, if the polyethylene terephthalate resin on the inner surface side of the mouth 3 is whitened and crystallized, practically sufficient heat resistance can be obtained. Therefore, the whitened and crystallized region 5 does not have to extend to the outer surface of the mouth. Good.

The degree to which the polyethylene terephthalate resin is whitened and crystallized depends on the degree of heating, but in the polyethylene terephthalate resin bottle body 1 of this embodiment, the heating for whitening and crystallization is carried out at the mouth as described later. 3 is performed from the inner surface side, the degree of heating gradually decreases from the inner surface side to the outer surface side of the mouth portion 3, and the boundary between the whitened region 5 and the non-whitened region 6 is not clear. Similarly, the boundary between the whitened region 5 and the non-whitened region 6 is not clear even near the boundary between the mouth 3 and the bottle body 2.

In the polyethylene terephthalate resin bottle body 1 of this embodiment, since the non-whitened region 6 exists on the outer peripheral side of the mouth portion 3, the mouth portion 3 and the transparent bottle body 2 are integrally observed. Further, since the whitened area 5 is observed through the non-whitened area 6 on the outer peripheral side, a unique gloss appears on the surface of the mouth portion 3,
An excellent effect can be obtained in terms of beauty.

In this example, the polyethylene terephthalate resin bottle body 1 was manufactured as follows.

In the manufacturing method of this embodiment, a molten polyethylene terephthalate resin is injected into a mold having a predetermined shape to form a mouth portion having a thread forming portion and a primary molded body of a bottomed cylindrical bottle body. An injection molding step of molding a bottle preform consisting of, and the bottle preform obtained in the injection molding step is heated with the outer peripheral portion of the mouth held by a mold, and the primary molded body of the bottle main body is heated. The temperature control process that adjusts the temperature of the bottle to a temperature suitable for blow molding, and the primary molded body of the bottle main body that is adjusted to the temperature suitable for blow molding in the temperature control process is blown along the shape of the blow molding mold. It comprises a blow molding step of forming a bottle body by molding and a demolding step of separating the bottle body obtained in the blow molding step from the blow molding die. Then, in the manufacturing method of the present embodiment, in the temperature control step, the primary molded body of the bottle main body is inserted into the temperature controller with the outer peripheral portion of the mouth portion being sandwiched by the mold, and the primary molded body is externally attached. While heating, the heating body is inserted into the inner surface side of the primary molded body to heat the vicinity of the boundary between the mouth portion and the primary molded body, and then the inner surface side of the mouth portion is heated by the heating body, so that the inner surface of the mouth portion is heated. The polyethylene terephthalate resin on the side is whitened and crystallized.

Next, the manufacturing method of this embodiment will be described in detail in the order of steps.

First, in the injection molding process, as shown in FIG. 3 (a), the primary molded body molding die 11 and the upper stage mouth molding die 1 are formed.
The polyethylene terephthalate resin 15 in a molten state is hot from the cylinder 16 in the preform molding die 10 for molding the preform 20 including the cavity 14 formed by the die 2a, the lower mouth molding die 12b and the incore 13. It is injected through the runner 17.

The hot runner 17 communicates with the cavity 14 and the cylinder 16 through the inside of the hot runner block 19 in which the heater 18 is arranged, and is maintained at about 280 ° C. In addition, inside the primary molded body forming die 11 and the in-core 13, a jacket 11a for circulating cooling water is provided.
And 13a are arranged, and the surfaces forming the cavity 14 of the primary molded body forming mold 11 and the in-core 13 are about 16
It is cooled to ℃.

The polyethylene terephthalate resin 15 in a molten state injected as described above is stored in the cavity 14
Inside, it is cooled and solidified, and molded into the shape of the preform 20 shown in FIG. The preform 20 includes a mouth part 3 having a thread forming part 4 on the outer periphery and a primary molded body 2 of a bottle body.
a.

After the preform 20 is solidified, FIG.
As shown in (b), the primary molding die 11, the mouth molding die 12b, and the in-core 13 are demolded, and the screw forming portion 4 is sandwiched by the mouth molding die 12a. Be transferred to.

In the temperature control step, the preform 20 is formed as shown in FIG.
As shown in, the screw forming portion 4 is inserted into the temperature adjusting device 21 while being sandwiched by the mouth forming die 12a. Temperature controller 2
No. 1 has a recess 21a corresponding to the shape of the preform 20 in the center and a jacket 22b in which a heated heat medium circulates inside. Then, the preform 20 inserted into the recess 21a is removed from the outside by about 70 to 90.
Heat to a temperature in the range of ° C.

At this time, in the preform 20, since the screw forming portion 4 is sandwiched by the upper-stage mouth forming die 12a, the mouth portion 3 is cooled, and the vicinity of the boundary between the mouth portion 3 and the primary molded body 2a. Hard to be heated. Therefore, a heating element 22 is inserted on the inner surface side of the preform 20 to assist heating in the vicinity of the boundary between the mouth 3 and the primary molded body 2a. The heating element 22 is 400-5
It is heated to about 00 ° C., and is heated so that the temperature near the boundary between the opening 3 of the preform 20 and the primary molded body 2a is about 100 ° C.

In the manufacturing method of this embodiment, the heating body 22 heats the vicinity of the boundary between the mouth 3 and the primary molded body 2a to the temperature within the above range, and then the heating body 22 is heated to the temperature shown in FIG.
And the polyethylene terephthalate resin on the inner surface side of the mouth 3 is heated to about 140 ° C. to be whitened and crystallized.

In the present embodiment, the heating of the inner surface side of the mouth portion 3 by the heating element 22 needs to be performed so that the polyethylene terephthalate resin on the inner surface side of the mouth portion 3 is surely whitened and crystallized, but up to the outer surface side. Whitening does not have to be crystallized.
Therefore, the heating of the inner surface side of the mouth portion 3 can be performed in a relatively short time. Further, since the heating of the inner surface side of the mouth portion 3 is performed in the same process as the temperature adjustment of the primary molded body 2a for blow molding, existing equipment can be used and the efficiency is extremely high.

In the preform 20 in which the inner surface side of the mouth 3 is whitened and crystallized, the screw forming portion 4 is then formed in the mouth forming die 12.
It is transferred to the blow molding process while being sandwiched by a.

In the blow molding process, the preform 20
As shown in FIG. 5 (a), the blow molding die 2 is held with the screw forming portion 4 held by the upper opening mouth forming die 12 a.
Set to 3. The blow molding die 23 is a bottle body 2
Has a shape matching the outer shape of the bottom mold 23a, split mold 2
It is designed to be divided into 3b and 23b.

Next, the primary molded body 2a of the bottle is shown in FIG.
As shown in (b), while being stretched in the axial direction by the stretch pin 24 inserted on the inner surface side, it is stretched in the circumferential direction by the gas introduced through the stretch pin 24 to have the shape of the mold 23. The bottle body 2 is obtained by blow molding.

Next, in the demolding step, as shown in FIG. 6, the bottom mold 23a is opened downward in the arrow direction, the split mold 23b is opened left and right in the arrow direction, and the bottle body 2 is blow-molded with the mold 23. Be separated from. Further, the mouth part forming die 12a
Open to the left and right in the direction of the arrow, and the polyethylene terephthalate resin bottle body 1 is obtained.

In the manufacturing method of the present embodiment, the injection molding process, the temperature control process, the blow molding process, and the blow molding process are performed on the four circumferences of the table rotatably provided with the preform 20 sandwiched by the upper-portion molding die 12a. It is preferable to use an apparatus provided with a demolding step. By using such a device, a bottle body made of polyethylene terephthalate resin 1
Can be continuously manufactured.

When using the above apparatus, it is desirable to select the heating conditions for the inner surface of the mouth 3 in accordance with the time required for each step.

[0039]

According to the bottle made of polyethylene terephthalate resin of the present invention, the mouth portion which is continuously formed with the bottle body and is integrally formed is formed of unstretched polyethylene terephthalate resin. The side is whitened,
Since it is a crystallized polyethylene terephthalate resin, it has improved heat resistance, and thermal deformation of the mouth can be avoided even when the contents are filled with heat. Therefore, according to the bottle of the present invention, the sealing property between the mouth portion and the cap is favorably maintained and the leakage of the contents can be prevented.

According to the bottle of the present invention, only the inner surface side of the mouth is whitened and crystallized, so that the surface of the mouth has a gloss and can be observed integrally with the bottle body which is transparent from the outside. .. Therefore, it is possible to avoid giving the impression that the mouth portion is composed of another member.

Further, according to the method for producing a polyethylene terephthalate resin bottle body of the present invention, in the temperature adjusting step of adjusting the temperature of the preform for blow molding, the mouth of the preform and the primary molded body of the bottle are formed. After the heating in the vicinity of the boundary is completed, the heating for assisting the heating in the vicinity of the boundary is continuously heated to crystallize the inner surface of the mouth portion.

Therefore, the polyethylene terephthalate resin on the inner surface of the mouth is surely whitened and crystallized, and only the practically sufficient range on the inner surface of the mouth needs to be whitened and crystallized. You can Also, the heating for whitening and crystallizing the inner surface side of the mouth is performed in the same process as the temperature adjustment of the primary molded body of the bottle for blow molding, so existing equipment can be used and extremely efficient. It is possible to manufacture a bottle of polyethylene terephthalate resin in which the inner surface of the mouth is whitened and crystallized.

Further, since the outer peripheral side of the mouth portion is sandwiched by the mold and cooled, it is possible to avoid deformation of the screw forming portion due to heating for whitening and crystallization.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a bottle made of polyethylene terephthalate resin of the present invention.

FIG. 2 is an explanatory cross-sectional view of the mouth of the bottle made of polyethylene terephthalate resin shown in FIG.

FIG. 3 is an explanatory sectional view showing an injection molding step in the manufacturing method of the present embodiment.

FIG. 4 is an explanatory cross-sectional view showing a temperature adjusting step in the manufacturing method of the present embodiment.

FIG. 5 is an explanatory cross-sectional view showing a blow molding process in the manufacturing method of this embodiment.

FIG. 6 is an explanatory cross-sectional view showing a demolding step in the manufacturing method of this embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Polyethylene terephthalate resin bottle body, 2 bottle body, 3 ... mouth part, 4 ... screw forming part, 5 ... whitening area, 6 ... non-whitening area, 20 ... preform, 21 ... temperature control device, 22
… Heating body.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // B29K 67:00 B29L 22:00 4F

Claims (2)

[Claims] 1. A bottle made of polyethylene terephthalate resin, comprising a biaxially stretched bottle body and an unstretched mouth portion provided above the bottle body, and having a thread forming portion on the outer periphery of the mouth portion. A bottle made of polyethylene terephthalate resin, characterized in that the mouth portion is continuously formed with the bottle body and integrally molded, and the inner surface side of the mouth portion is whitened and crystallized. 2. A bottle mold comprising a mouth-shaped portion having a thread forming portion and a primary molded body of a bottle-shaped bottle body having a bottom, by injecting a molten polyethylene terephthalate resin into a mold having a predetermined shape. The injection molding step of molding the reform, and the bottle preform obtained in the injection molding step is heated in a state in which the mouth outer peripheral portion is sandwiched by the mold to heat the temperature of the primary molded body of the bottle body to blow molding. A temperature control step of adjusting the temperature to a suitable temperature, and a bottle body by blow molding the primary molded body of the bottle body adjusted to a temperature suitable for blow molding in the temperature control step along the shape of the blow molding die. In the method for producing a polyethylene terephthalate resin bottle body, which comprises a blow molding step of forming a blow mold step, and a demolding step of separating the bottle body obtained in the blow molding step from the blow molding die, in the temperature adjusting step, While inserting the primary molded body of the bottle main body into the temperature control device while sandwiching the outer peripheral portion of the mouth with the mold, the primary molded body is heated from the outer surface side, and the heating body is provided on the inner surface side of the primary molded body. A method for producing a polyethylene terephthalate resin bottle body, which comprises inserting and heating the vicinity of the boundary between the mouth portion and the primary molded body, and then heating the inner surface side of the mouth portion by the heating body.