JP3356035B2 - Biaxially stretch blow molded bottle and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxially stretched blow molded bottle obtained by biaxially stretch blow molding a preform obtained by injection molding and made of a thermoplastic resin such as polyethylene terephthalate, and a method for producing the same.

[0002]

2. Description of the Related Art Biaxially stretched blow molded bottles, for example, biaxially stretched blow molded bottles made of a thermoplastic resin such as polyethylene terephthalate (PET) have excellent transparency, impact resistance, gas barrier properties, fruit juice drinks, coffee , Oolong tea, carbonated beverages containing fruit juice, carbonated beverages, etc., are widely used as bottles for various beverages.

[0003] Heat-resistant bottles filled with fruit juice drinks, coffee, oolong tea, etc., are filled hot at about 90 ° C, and heat-resistant pressure bottles filled with fruit juice-containing carbonated drinks are filled with content. Later, since sterilization at 60 to 80 ° C. is performed, in order to prevent deformation due to heat and to secure sealing with the cap, after injection molding the preform, heat is applied to impart heat resistance to the mouth. A crystallization process is being performed.

Japanese Utility Model Application Laid-open No. Sho 60-105,116 discloses a means for enhancing the sealing performance between the mouth of a bottle and a cap. At the upper end of the outer peripheral surface, a bulging portion is provided with a projection height equal to the amount of contraction deformation of the upper end, and the boundary portion between the outer peripheral surface and the upper end surface of the mouth does not shrink and deform more than other parts. It is what we did.

[0005] In addition, Japanese Utility Model Application Laid-Open No. 52-111,770
The disclosure also discloses that an outwardly protruding edge is provided on the outer periphery of the mouth end of the preform so that the opening end face has a flat surface shape having a desired width.

[0006] However, these are shrinkage-deformation at the mouth of the bottle, especially at the side of the upper end thereof when receiving the heat history of the heat-resistant and pressure-resistant bottle, or after the bottle is formed into a pressure-resistant and aseptic filling bottle. No consideration has been given to the problem that the temporal deformation causes the adhesiveness of the inner surface of the cap to the sealing material to be reduced, and it has not been satisfactory.

[0007]

As described above, the mouth of the heat-resistant bottle and the heat-resistant pressure-resistant bottle is prevented from being deformed due to heat at the time of filling and sterilizing, and the sealing performance with the cap is ensured. Thermal crystallization is performed, and after filling, it is sealed with a plastic cap or the like.

However, even if thermal crystallization of the mouth portion is performed, as shown in FIG. 5, the mouth portion 1, particularly the side surface of the upper end portion 2 thereof, undergoes thermal crystallization, hot filling, Alternatively, heat at the time of sterilization causes shrinkage deformation and inward collapse A, and the opening angle and the desired leak angle at which the sealing state of the cap having the sealing material on the inner surface is released are reduced, and the sealing performance is reduced.

Similarly, as shown in FIG. 6, since the mouth 1 of the preform is injection-molded in a split mold, burrs B are easily formed at symmetrical positions on the side surfaces of the upper end 2 and the cap is formed. After sealing by, indentations of burrs B are formed on the sealing material on the inner surface of the cap, and similarly, the opening angle of the cap is reduced, and the sealing performance is reduced.

In particular, the above phenomenon is often observed when a plastic cap having a sealing material such as polyethylene on the inner surface is employed as the cap.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been proposed to solve the above-mentioned problem, and has a thread on the side face of a thermally crystallized mouth and a side face at the upper end of the mouth. one 0.03mm~0.70mm protruding lower end is convex curved outward
Or a biaxially stretched blow-molded bottle having a tapered peripheral projection formed thereon. Further, according to the present invention, a temporary circumferential projection projecting outward is formed on the upper end side surface of the mouth of the preform having a thread on the mouth side surface, and then the mouth portion of the preform is thermally crystallized. At the same time, the temporary circumferential projection is thermally contracted so that one side is
A method for manufacturing a biaxially stretched blow-molded bottle is provided, wherein the preform is biaxially stretch-blown and blow-molded after forming a circumferential projection having a convex curved surface or a tapered surface .

[0012]

According to the biaxially stretch blow-molded bottle of the present invention,
In a biaxially stretched blow-molded bottle with a heat-crystallized mouth, the mouth, especially the upper end, is thermally crystallization of the mouth, hot filling, shrinkage deformation due to heat during sterilization, and during preform injection molding, Even if burrs are formed on the upper end of the mouth, the opening angle and the desired leak angle of the cap after sealing are not reduced, and a decrease in sealing performance is prevented. Furthermore, according to the method for producing a biaxially stretched blow-molded bottle of the present invention, a circumferential projection that protrudes outward on the side of the upper end portion at the mouth of the biaxially stretched blow-molded bottle can be reliably and easily formed. It can be formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a view showing a mouth portion of a biaxially stretched blow-molded bottle of the present invention, wherein 1 is a mouth portion, 2 is an upper end portion, 3 is a circumferential projection, 4 is a screw portion, and 5 is a neck ring. Is an enlarged view of the mouth 1, and is formed on the entire circumference so that a circumferential projection 3 projects radially outward on the side surface of the upper end 2 as shown by a solid line.

First, a heat-resistant and heat-resistant biaxial stretch blow-molded bottle whose mouth 1 is thermally crystallized will be described with reference to FIGS.

The circumferential protrusion 3 formed on the side surface of the upper end 2 of the mouth 1 has a temporary circumferential protrusion 6 having a protrusion width α at the upper end 2 shown by a dashed line in FIG. The mouth 1 of the reform is thermally crystallized, and the temporary circumferential protrusion 6 is thermally contracted to the circumferential protrusion 3 shown by the solid line in FIG.
A heat-resistant, heat-resistant, biaxially stretched blow-molded bottle having the above-mentioned circumferential projection 3 of 0.70 mm.

The projection width β of the circumferential projection 3 is
If it is less than 0.03 mm, the effect of increasing the opening angle of the cap cannot be obtained due to shrinkage deformation of the side surface of the upper end portion 2 due to heat or indentation of the sealing material on the inner surface of the cap due to burrs during preform molding. Can not prevent the decline in sex.

The projection width β of the circumferential projection 3 is 0.7
If it exceeds 0 mm, the sealing material on the inner surface of the cap screwed into the mouth 1 is too close to the side surface of the upper end 2 of the mouth 1,
The initial opening force of the cap is increased, making it difficult to open the cap.

On the other hand, the shape of the lower end of the circumferential projection 3 is
The convex curved surface shown in FIG. 2 is preferable from the viewpoint of preventing the inner surface of the cap from being damaged by the sealing material.

The shape of the lower end of the circumferential projection 3 is as follows.
Although the taper surface shown in FIG. 3 may be used, the angle θ in this case is 2
0 to 70 degrees is desirable, and if it is less than 20 degrees, the circumferential protrusion 3
Even when the sealing material is formed, the sealing material on the inner surface of the cap is easily affected by burrs, and if it exceeds 70 degrees, the resistance at the time of capping increases, and the sealing material on the inner surface of the cap tends to be damaged.

The method for manufacturing the heat-resistant and heat-resistant biaxially stretched blow-molded bottle is, as shown by the one-dot chain line in FIG. 2 or FIG. A preform of 0.05 to 1.00 mm on one side and having a temporary circumferential projection 6 whose lower end is substantially horizontal is injection molded.

When the protrusion width α is less than 0.05 mm, the circumferential protrusion 3 protruding radially outward due to heat shrinkage during thermal crystallization of the mouth portion 1 described below causes the mouth portion 1 to have the protrusion width α smaller than 0.05 mm. Part 1
Is not reliably formed on the side surface of the upper end portion 2 of the
If it exceeds mm, crystallization is not sufficiently transmitted during thermal crystallization, and the heat resistance and the uniformity of the diameter of the upper end 2 of the mouth 1 cannot be sufficiently obtained.

Next, the mouth 1 of the preform is thermally crystallized at a crystallization temperature, and the temporary circumferential projection 6 on the side surface of the upper end 2 is heated to a shape shown by a solid line in FIG. 2 or FIG. The protrusion width β is 0.03 to 0.70 mm on one side, and the lower end is a convex curved surface shown in FIG. 2 or the angle θ shown in FIG.
A circumferential projection 3 having a tapered surface of 0 to 70 degrees is formed.

Thereafter, the preform is heated to a temperature at which it can be biaxially stretched to perform biaxial stretch blow molding, and the body is heat-fixed to impart heat resistance or time-dependent deformation resistance. A heat-resistant, heat-resistant, biaxially stretched blow-molded bottle having a circumferential projection 3 projecting outward on the side surface of the upper end 2 of 1 is obtained.

In the following table, numerical values of the opening angle (leak angle) of the cap of the biaxially stretched blow-molded bottle of the present invention and the conventional biaxially stretched blow-molded bottle having heat resistance and heat pressure are shown.

[0025]

[Table 1]

[0026]

According to the present invention, there is provided a heat-resistant, heat-resistant pressure-resistant biaxially stretched blow-molded bottle having a thermally crystallized mouth.
The mouth, especially the side surface of the upper end portion is thermally crystallized, hot-filled, shrinks and deforms due to heat during sterilization, or, even if there is a burr at the upper end of the mouth during preform injection molding,
The opening angle of the cap and the desired leak angle are not reduced, and a decrease in sealing performance is prevented. Further, according to the method for producing a biaxially stretched blow-molded bottle of the present invention, a circumferentially projecting portion that protrudes outward is reliably and easily formed on the upper end side surface of the mouth of the above-described biaxially stretched blow-molded bottle. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a view showing a mouth portion of a biaxially stretch blow-molded bottle of the present invention.

FIG. 2 is an enlarged view of a mouth portion of the biaxially stretch blow-molded bottle of the present invention.

FIG. 3 is an enlarged view of another mouth portion of the biaxially stretch blow-molded bottle of the present invention.

FIG. 4 is an enlarged view of a mouth portion of a biaxially stretch blow molded bottle of a reference example .

FIG. 5 is a view showing a mouth portion of a conventional biaxially stretch blow-molded bottle.

FIG. 6 is an enlarged view of a mouth portion of a conventional biaxially stretch blow-molded bottle.

Claims (2)

(57) [Claims] 1. A heat-crystallized mouth has a thread on the side face and an outer side with 0.03 mm to 0.7 mm on one side on the side face at the upper end of the mouth.
Biaxially stretch blow molded bottles, characterized in that 0mm protruding lower end to form a circumferential projection of convex curved surface or tapered surface. 2. A preform having a thread on a side surface of a mouth is formed with a temporary circumferential projection protruding outward on a side surface of an upper end portion of the mouth portion, and then the mouth portion of the preform is thermally crystallized. ,
Heat shrink the temporary circumferential projection to 0.03 mm outward on one side
A biaxially stretch blow-molded bottle, wherein the preform is biaxially stretch-blow-molded after forming a circumferential projection having a convex curved surface or a tapered surface protruding by 0.70 mm.