JPH09315420A - Self standing polyester bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self standing polyester bottle which is heat resisting and pressureproof without the deformation of the bottom or the expansion of the body part of the bottle when the bottle filled with a content liquid having high internal pressure is heat sterilized and whose leg part for making the bottle self standing is integrally formed. SOLUTION: The bottom of this biaxial stretching self standing polyester bottle is provided with 3 or more leg parts 5 which have a ground plane 51 projecting radially and downward with equal intervals in the outer peripheral direction of a roughly hemispheric shaped bottom face. The body part 3 of the bottle is formed by stretch blow in its peripheral direction, and a mouth closure part 1 and bottom part 4 are heat processed. When the distance of horizontally crossing point A from the bottom center point O to the body wall is d, the distance from the bottom center point O to the hemispheric shape bottom center point B is h, and the length from the horizontally crossing point A to the hemispheric shaped bottom center point B is L, the relation expressed by (d<2> +h<2> )<1/2> <L<=1.10(d<2> +h<2> )<1/2> is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is filled with a liquid having a high internal pressure such as a beverage containing a gas containing fruit juice, has heat resistance and pressure resistance to withstand heat sterilization, and is integrally formed with legs for self-standing. Freestanding polyester bottle.

[0002]

2. Description of the Related Art Generally, as a plastic hollow container, a polyester bottle formed by stretch blow molding of polyethylene terephthalate (hereinafter sometimes simply referred to as PET) is widely used as a packaging container for a gas-containing beverage containing fruit juice. ing.

In these polyester bottles, a bottomed preform obtained by injection molding is placed in a cavity of a heated blow mold, and the preform is longitudinally stretched by a stretching rod, and at the same time, in the preform. It is blow-stretched in the vertical and horizontal biaxial directions by the pressure of the high-pressure gas blown into to form a bottle body, and this blow-stretched bottle body is brought into contact with the blow-molding die to solidify and then taken out from the blow-molding die Are molded.

[0004] The bottom of the bottle body, which is formed by biaxial stretch blow molding of polyester resin, is composed of a spigot, a shoulder, a body, and a bottom, and a leg forming a grounding portion is formed in the outer peripheral direction of a substantially hemispherical bottom surface. A so-called one-piece bottle, which is a self-supporting polyester bottle formed by integrally molding a plurality of pieces radially at equal intervals, is also widely used.

[0005]

These self-supporting polyester bottles are required to have an internal pressure resistance of, for example, 10.5 kg / cm ² or more at room temperature when the filling content liquid is a carbonated beverage, which is satisfied. .

However, for the purpose of heat sterilizing the content liquid containing fruit juice or the like, if the bottle is filled with a relatively cold content liquid and then hot water is applied to the bottle (heat shower) for sterilization, the internal pressure resistance of the bottle is sufficient. Therefore, it may not be able to withstand the high internal pressure when subjected to high temperature treatment, the bottom of the bottle may be deformed and it may not be able to maintain its uprightness, or the body of the bottle may expand and the internal volume may change. There are things you can do.

[0007]

According to the present invention, the bottle bottom portion is deformed or the bottle body is expanded even when a content liquid having a high internal pressure such as a juice-containing gas-containing beverage is filled and subjected to heat sterilization treatment. It has heat resistance and pressure resistance that does not
In addition, it is intended to provide a self-supporting polyester bottle in which legs for self-supporting are integrally molded, the gist of which is a biaxially stretch blow molded polyester resin spout, shoulder, body, and bottom. In a self-supporting polyester bottle, the bottom part of which is provided with at least three legs having downwardly radially projecting grounding surfaces at equidistantly spaced locations on the bottom surface of a downwardly convex, substantially hemispherical bottom surface, at least the body part Is stretch blow-molded 4.0 times to 4.6 times in the circumferential direction, and at least the spout and bottom are heat treated, and the bottom is on the horizontal line from the bottom center point (O) to the body wall. The distance to the intersection (A) is d and the bottom center (O)
When the distance from the center point (B) of the substantially convex hemispherical bottom surface to the downward convex is h, and the length from the intersection (A) on the horizontal line to the center point (B) of the substantially hemispherical bottom surface of the downward convex is L, A self-supporting polyester bottle having a relationship of d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ² ) ^1/2 .

And a biaxially stretched blow molding of polyester resin, which comprises a plug portion, a shoulder portion, a body portion, and a bottom portion. 3 legs with a protruding ground plane
In a self-supporting polyester bottle provided in more than one place, at least the body part is stretch blow molded 4.0 to 4.6 times in the circumferential direction, and at least the spout part and the bottom part are heat treated, and at the bottom part thereof, A self-supporting polyester bottle in which a bell-shaped upward concave portion having a diameter (D) of the opening portion smaller than a depth (H) from the opening portion to the innermost portion is formed on a bottom surface of a substantially hemispherical downward convex shape.

Polyethylene terephthalate composed of terephthalic acid and ethylene glycol is suitable as the polyester constituting the bottle body of the present invention, but 10 mol% or less of another dicarboxylic acid and / or another dihydroxy compound is copolymerized. You can do it. The intrinsic viscosity (IV) of the polyester is in the range of 0.5 to 1.0, preferably 0.6 to 0.9.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The self-supporting polyester bottle of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a front view showing an example of the self-supporting polyester bottle of the present invention, and FIG. 2 is a schematic end view of the bottom of FIG.
FIG. 3 is a schematic end view of the bottom portion showing another example of the self-supporting polyester bottle of the present invention.

The self-supporting polyester bottle of the present invention comprises a plug portion 1 formed by biaxially stretch blow molding a polyester resin,
It is composed of a shoulder portion 2, a body portion 3, a bottom portion 4 and the like.

On the bottom portion 4, five leg portions 5 are formed so as to radially project downward at equal intervals in the outer peripheral direction of a substantially hemispherical bottom surface 41 which is convex downward.

Each of the legs 5 has a distance d from the center point (O) of the bottom of the bottle body to the intersection (A) on the horizontal line from the bottom wall of the body to the center of the bottom of the bottle body (O). From the bottom to the bottom center point (B)
A downward support portion 52 having a ground contact surface 51 is provided and formed on a downward convex substantially hemispherical bottom surface 41 having a curved surface. Here, the bottom center point (O) of the bottle body is located on the vertical center axis of the bottle and at a height where it transitions from the body portion 3 to the substantially hemispherical bottom surface 41 of the bottom portion 4.

The length L from the intersection (A) on the horizontal line to the center point (B) of the bottom surface of the downwardly convex substantially hemispherical shape is (d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ^2). ) ^1/2 relationship is set.

Alternatively, as shown in FIG. 3, on a bottom surface 41 having a substantially hemispherical shape that is convex downward, a diameter (D) of the opening 61 is smaller than a depth (H) from the opening 61 to the innermost portion 62. The upward concave portion 6 is formed.

For molding a self-supporting bottle, polyester is injection-molded to obtain a bottomed preform, and the plug portion of this preform is heat-treated at a high temperature (about 240 ° C.) to be whitened by crystallization, Then, this preform is
After preheating at ˜110 ° C., it is placed in a blow mold which is heated to 40 to 120 ° C., preferably 50 to 90 ° C., a stretching rod is inserted into the preform, and at the same time it is stretched, A compressed gas is blown in, and the stretching ratio in the longitudinal and lateral biaxial directions is, for example, 2.3 to 2.7 times in the axial direction.
The bottle body is formed by stretch-blowing the body in the circumferential direction to a draw ratio of 4.0 to 4.6 times, preferably 4.3 to 4.6 times in the body portion, and the bottom portion of the obtained bottle body is set to 100. The temperature of the bottle body is increased by heating it to 130 ° C. or higher, preferably 130 to 150 ° C., to bring it into contact with the surface of this mold or another mold for crystallization to increase the density, After cooling to below the glass transition point of, the bottle body is taken out from the blow molding die.

As a result, the body of the self-supporting bottle is highly biaxially molecularly oriented and crystallized to 34% or more, and the tensile strength in the circumferential direction is 1800 kg / cm ² or more, preferably 2000 to 3000 kg / cm. ² and the bottom has a density of 1.365 g / cm ^3, preferably 1.370.
It is g / cm ³ or more.

As a result, in the self-supporting polyester bottle of the present invention, the mouth part is whitened by crystallization by heat treatment to impart heat resistance and pressure resistance, and the shoulder part and the body part are highly stretched, and particularly The draw ratio in the circumferential direction of the body is 4.0
To 4.6 times preferably a circumferential direction tensile strength was stretched 4.3 to 4.6 times 1800 kg / cm ² or more, preferably improved heat-pressure resistance by the 2000~3000kg / cm ² As shown in the figure, the bottom portion is provided with three or more leg portions 5 each having a downwardly radially projecting grounding surface 51 at equidistant locations on the outer circumferential direction of the downwardly convex substantially hemispherical bottom surface 41, and from the bottom center point (O). Let d be the distance to the intersection (A) on the horizon that reaches the body wall, and h be the distance from the center of the bottom (O) to the center point of the bottom surface of the generally convex hemisphere (B).
When the length from the intersection (A) on the horizontal line to the center point (B) of the bottom surface of the downward convex convex hemisphere is L, (d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ² ) ¹ It is set to the relationship of ^{/ 2} .

Alternatively, a substantially hemispherical bottom surface 41 which is downwardly convex
In addition, the diameter (D) of the opening 61 is from the opening 61 to the innermost portion 6
Bell-shaped upward recess 6 smaller than the depth (H) reaching 2
There was formed, moreover so that the its density 1.365 g / cm ^3, preferably by a 1.370g / cm ³ or more brings a heat-pressure resistance.

In this case, the depth (H) is preferably about 1.2 to 3.0 times the diameter (D), and the diameter (D) is about 0.1 to 0.3 times the body diameter 2d. preferable.

[0022]

Examples 1 to 3 and Comparative Examples 1 to 2 IV 0.85 polyethylene terephthalate was injected, and the weight was 54 g, the body outer diameter was 25.0 mm, the wall thickness was 4.5 mm, the total length was 150 mm or the outer diameter was 27.5 mm. Wall thickness 4.0 mm, total length 150
A bottomed preform having a diameter of mm was obtained, and the plug part of this preform was heated to 180 ° C. with an infrared heater to crystallize (whiten) only the plug part.

This preform is heated by an infrared heater at 95 ° C.
And soften it to heat the preform to 85 ℃
While biaxially stretching and blowing in a blow molding die heated to a bottom temperature of 130 ° C., the bottle body is molded by stretching the circumferential stretching ratio to 4.0 or 4.5 times in the barrel portion, It is held in the blow molding die for 8 seconds and heat-treated to have a body outer diameter of 93 mm, a total height of 305 mm, and a body thickness of 0.3 to
A self-supporting bottle having a size of 0.5 mm and an internal volume of 1.5 L shown in FIG. 2 was obtained.

The bottom dimension of this self-supporting bottle is shown in FIG.
, The distance d from the bottom center point (O) to the intersection (A) on the horizontal line from the bottom wall to the trunk wall is 46 mm, and the distance h from the bottom center (O) to the downward convex substantially hemispherical bottom surface center point (B) is 40 mm. Therefore, (d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ² ) ^1/2 and the bottom density was 1.370 g / cm ³ .

The length L from the intersection (A) on the horizontal line to the center point (B) of the downwardly convex, substantially hemispherical bottom surface was set to 62.8 mm to 70.1 mm as shown in Table 1.

As shown in Table 1, the tensile strength in the body circumferential direction was 1800 to 2100 kg / cm ² .

Each of the self-supporting bottles of Examples 1 to 3 and Comparative Examples 1 and 2 was filled with 2.5 GV (volume of carbon dioxide gas dissolved in 1 L of water at 20 ° C.) of carbonated water and capped. Table 1 shows the results of measuring and observing the self-sustaining property, the rate of increase in the barrel diameter, and the liquid leakage by performing a heat sterilization treatment by showering hot water of 70 ° C. for 40 minutes on these.

However, the measuring method of tensile strength: AST
According to MD-1822.

Density measuring method: By a density gradient tube method.

Cylinder diameter increase rate (%): (Cylinder diameter after filling / Cylinder diameter after filling-1) × 100 Self-supporting property, liquid leakage; Presence / absence was visually determined.

Evaluation: With self-supporting property, no liquid leakage, body diameter increase rate of 3% or less ... ○ With self-supporting property, no liquid leakage, body diameter increase rate of 3% or more, 5% or less ... △ Self-supporting property No or leaking… ×

[Table 1] As shown in Table 1, the length L is 1.10 (d ² + h ² ).
^The comparative example 1 in which 70.1 is larger than ^1/2 = 67.1 is not self-sustaining, and the comparative example 2 in which the spout is not whitened causes liquid leakage and internal pressure Because of the removal, the rate of increase (%) of the barrel diameter contracted to -10%, and the evaluation was x in both cases.

Further, the length L is (d ² + h ² ) ^1/2 = 6
Greater than 0.96, 1.10 (d ² + h ² ) ^1/2 = 6
All of Examples 1 to 3, which are 7.1 or less, have self-sustaining property and the plug portion is whitened, so that there was no liquid leakage. And especially the draw ratio is 4.5 times and the length L is 6
In Example 1 of 2.8, the barrel diameter increase rate was 3%, which was the most excellent.

[0033]

Examples 4 to 5 and Comparative Examples 3 to 5 IV 0.85 polyethylene terephthalate was injected, and the weight was 54 g, the outer diameter of the body was 23.5 to 27.5 mm, the wall thickness was 4.0 to 5.0 mm, and the total length was 150 mm. Get the bottomed preform of
Or use the infrared heater for the plug part of this preform.
It was heated to 80 ° C. to crystallize (whiten) only the plug part.

This preform is heated to 95 ° C. with an infrared heater.
And soften it to heat the preform to 85 ℃
Biaxial stretching is blown in a blow molding die heated to a bottom temperature of 130 ° C., and the stretching ratio in the circumferential direction is 4.0 in the barrel portion.
While stretching the bottle body 5.0 times to mold the bottle body, it is held in the blow molding die for 8 seconds and heat-treated to have a body outer diameter of 93 mm, a total height of 305 mm, and a body wall thickness of 0.3 to 0.5 m.
A self-supporting bottle having an inner volume of 1.5 L and a bell-shaped upward concave portion formed in the center of the bottom surface shown in FIG. 3 was obtained.

The diameter (D) of the opening 61 of the bell-shaped upward recess 6 is 20 to 25 mm, and the depth (H) from the opening 61 to the innermost portion 62 is 10 to 45 mm.

The density of the bottom of this self-supporting bottle is 1.37.
The tensile strength in the circumferential direction of the body was 0 g / cm ³ , and as shown in Table 2, it was 1800 to 3100 kg / cm ² .

This self-supporting bottle was filled with 2.5 GV of carbonated water, capped, and warmed at 70 ° C. to 40 ° C.
Table 2 shows the results of measuring and observing the self-sustaining property, the rate of increase in the body diameter, and the liquid leakage after showering for minutes and performing heat sterilization treatment.

[0038]

[Table 2] As shown in Table 2, in Comparative Example 3 having a draw ratio of 5.0 times and 4.6 times or more, the moldability was deteriorated and the transparency was deteriorated, an evaluation sample was not obtained, and the mouth plug portion was In the case of Comparative Example 4 which is not whitened, liquid leakage occurs and the internal pressure is released, so that the barrel diameter increase rate (%) is contracted to -10%, and the diameter (D) of the opening 61 is deep. The sample of Comparative Example 5, which was larger than (H), had no self-sustaining property and was evaluated as x in all cases.

Further, all of Examples 4 to 5 in which the diameter (D) of the opening 61 is smaller than the depth (H) are self-supporting and the mouth plug is whitened, so that the liquid is also present. There was none. Especially, in Example 4 in which the draw ratio was 4.5 times, the barrel diameter increase rate was 3%, which was the most excellent.

[0040]

The self-supporting polyester bottle of the present invention is
It consists of a spigot, shoulder, body, and bottom, and at the bottom, three or more legs with downwardly radially projecting ground planes are provided at equidistant locations on the bottom surface of a downwardly convex, substantially hemispherical base. In a biaxially stretch blow-molded self-supporting polyester bottle, at least the body portion has a circumferential direction of 4.0.
~ 4.6 times stretch blow molded, at least the plug part,
The bottom is heat-treated, and the bottom is a substantially hemispherical bottom surface that is downwardly convex from the center of the bottom (O), where d is the distance from the center of the bottom (O) to the intersection (A) on the horizontal line that reaches the body wall. Assuming that the distance to the center point (B) is h and the length from the intersection point (A) on the horizon to the center point (B) of the bottom surface of the generally downwardly convex hemisphere is L, (d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ² ) ^1/2 is set, so that in order to sterilize by heating, a relatively cold content liquid is filled into a bottle, and then hot water is poured onto the bottle ( Even if it is sterilized by hot shower), the appearance of the bottle, which is deformed at the bottom and the body, and the change in the internal capacity are prevented, and the commercial value thereof is not reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a self-supporting polyester bottle of the present invention.

FIG. 2 is a schematic end view of the bottom.

FIG. 3 is a schematic end view of the bottom showing another example of the self-supporting polyester bottle of the present invention.

[Explanation of symbols]

 1 Plug 2 Shoulder 3 Body 4 Bottom 41 Substantially hemispherical bottom 5 Leg 51 Ground contact surface 52 Downward support 6 Bell-shaped upward recess (O) Bottom center point (A) Horizontal intersection (B) Bottom center Point d (O) (A) distance h (O) (B) distance L (A) (B) length

Claims (2)

[Claims] 1. A leg portion comprising a spout portion, a shoulder portion, a body portion, and a bottom portion, and the bottom portion having a grounding surface projecting downward in a radial direction at equidistantly spaced locations in the outer circumferential direction of a downwardly convex substantially hemispherical bottom surface. In a biaxially stretch blow molded self-supporting polyester bottle having three or more locations, at least the body is stretch blow molded 4.0 to 4.6 times in the circumferential direction, and at least the spout and bottom are heat treated. In addition, the bottom is defined as a distance from the center point of the bottom (O) to the intersection point (A) on the horizontal line to the body wall, and the bottom center point of the bottom surface (O) is a substantially hemispherical shape. Let h be the distance to B),
Assuming that the length from the intersection (A) on the horizontal line to the center point (B) of the downwardly convex substantially hemispherical shape is L, (d ² + h ² ) ^1/2 <L ≦ 1.10 (d ² + h ² ) A self-supporting polyester bottle characterized by being set to a ^1/2 relationship 2. A biaxially stretch-blown polyester resin comprising a plug portion, a shoulder portion, a body portion, and a bottom portion, the bottom portion of which is directed downward at equally spaced locations in the outer circumferential direction of a generally downwardly convex hemispherical bottom surface. In a self-supporting polyester bottle in which three or more legs having radially projecting ground planes are provided, at least the body is stretch blow molded 4.0 to 4.6 times in the circumferential direction, and at least the plug portion, The bottom is heat-treated, and the bottom has a generally hemispherical bottom surface that is convex downward, and the diameter (D) of the opening is smaller than the depth (H) from the opening to the innermost part. Self-supporting polyester bottle characterized by being formed