JPS61217337A - Manufacture of bottle made of saturated polyester resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for obtaining a thin walled saturated polyester resin bottle whose parts other than the mouth and neck are biaxially stretched. The object of the present invention is to provide a method for producing a thin saturated polyester resin bottle that does not cause excessive wall thinning, which causes a decrease in the rigidity, strength, etc. of the resulting saturated polyester resin bottle.

[Conventional technology]

As a method of obtaining synthetic resin bottles to replace conventional glass bottles, a method of obtaining saturated polyester resin bottles by bi'-axial stretch blow molding has been proposed from the viewpoint of hygiene, toughness, etc.

However, as a method for obtaining a bottle made of saturated polyester resin whose parts other than the mouth and neck are biaxially stretched,
An intermediate material consisting of a bottomed hollow body with an open edge at the upper end is molded by injection molding, etc., and this intermediate material is heated to a stretching temperature and biaxially heated in a blow molding mold. A biaxial stretch blow molding method that performs stretch molding is common.

[Problem that the invention seeks to solve]

By the way, in the method for obtaining a bottle made of a saturated polyester resin whose parts other than the mouth and neck are biaxially stretched, since the degree of reinforcement is increased by biaxial stretching, it is difficult to carry out biaxial stretching blow molding. It is desirable to increase the stretching ratio of the bottle, and as a result, the wall thickness becomes small and a molded bottle that is easily deformed and lacks rigidity and strength is likely to be formed. This tendency is particularly severe at the bottom periphery (boundary edge between the bottom and body) of the molded bottle, which is extremely prone to thinning during bottle molding.
This method has the disadvantage that it is easy to obtain a bottle with insufficient rigidity and strength at the bottom of the bottle.

On the other hand, in the method for producing a saturated polyester resin bottle of the present invention, the bottom part of the bottle is particularly reinforced, and the bottle has a thin wall that not only has excellent internal pressure resistance but also has a good appearance. The present invention provides a method for easily and reliably obtaining a saturated polyester resin bottle.

[Means for Solving the Problems] The method for producing a saturated polyester resin bottle of the present invention involves placing an intermediate material consisting of a bottomed hollow body made of saturated polyester resin, usually called a piece, in a blow molding mold. Biaxial stretch blow molding is performed. That is, when carrying out the biaxial stretch blow molding, a neck part whose upper end is an open mouth edge part, a body part continuous to the neck part, and a body part continuous to the body part whose lower end is a round bottom top part. an intermediate material consisting of a bottomed hollow body having a plurality of solid protruding ribs formed radially from the top of the round bottom toward the bottom end of the body on the inner circumferential surface; By heating the intermediate material to an appropriate temperature for stretching, and performing biaxial stretching blow molding in a blow mold, a plurality of solid protrusions radially extending from the center of the bottle bottom to the bottom of the bottle body are formed. A thin saturated polyester resin bottle having ribs on the inner peripheral surface of the bottle is obtained.

〔Example〕

The specific structure of the method for manufacturing a saturated polyester resin bottle of the present invention will be described below with reference to the drawings.

The intermediate material used in the method of the present invention, indicated by reference numeral 1 in FIG. 1, is an injection molded product made of saturated polyester resin.
A neck part 3 having a screw 2 for screwing the cap protruding from the outer peripheral surface and an open mouth edge at the upper end, a body part 4 that is continuous to the neck part 3, and a body part 4 that is continuous to the body part 4 and has a round lower end. It is a bottomed hollow body composed of a bottom apex 5 and a bottom 6. From the round bottom top part 5 to the lower part of the body part 4, a plurality of solid protruding ribs 8, 8.・
... are configured to protrude radially from the inner peripheral surface of the bottomed hollow body. The plurality of solid protruding ribs 8°8, . The upper end of the solid protruding rib on the bottle body side of the bottle obtained by attaching to the bottle is located above a horizontal plane including the upper surface of the cap-shaped portion of the bottom wall of the bottle. By protruding from the inner circumferential surface of the bottomed hollow body, the effect exerted by the ribs of the protrusions on the resulting bottle will be perfect.

The intermediate material used in the method for manufacturing a saturated polyester resin bottle of the present invention having the above-mentioned structure is formed by forming a core having a recess formed on the outer peripheral surface when molding the intermediate material by injection molding. It can be easily obtained by using

Next, the intermediate material having the above structure is heated to an appropriate temperature for stretching,
The intermediate material is placed in a blow molding mold, and compressed air is blown into the inside of the intermediate material. At the same time, the inner bottom of the intermediate material is pressed down using a push-down rod to perform biaxial stretch blow molding. A bottle having an outer shape that matches the shape of the inner circumferential surface is obtained.

In the method of this embodiment, as a blow molding mold in which the intermediate material heated to an appropriate temperature for biaxial stretching is set, the solid part of the inner circumferential surface of the bottom part is formed into a cap-shaped part that protrudes upward. When the above-mentioned intermediate material is biaxially stretched and blow-molded in a mold having the above-mentioned shape, the central part of the bottom wall of the bottle becomes a cap-shaped part that protrudes inward from the bottle, as shown in the table. In addition, a saturated polyester resin bottle is obtained in which a plurality of solid protruding ribs are provided radially on the inner peripheral surface of the bottle from the upper end of the cap-shaped portion toward the lower end of the body. In the method for manufacturing a saturated polyester resin bottle of the invention, the shape of the blow mold when biaxially stretch blow molding the intermediate material is not limited to that in the example method, but can be A general blow molding mold used for obtaining synthetic resin bottles by axial stretch blow molding can be used.

The bottle designated by the reference numeral 9 in FIG. 2 is an example of a saturated polyester resin bottle obtained by the method according to the present invention, and the body portion 4 and bottom portion 6 on the intermediate element side 1 described above are Bottle body 1 which is biaxially stretch blow molded and has a cylindrical shape with a circular cross section.
o and the bottom wall 11 of the bottle.

The saturated polyester resin bottle 9 is made of intermediate material 1.
The neck part 3 has a shape of a neck part 3 as it is, the body part 10 has a cylindrical shape with a circular cross section and has a shoulder part 10A having a rounded upper part, and the center part thereof is a bottle shape. A bottom part 11 which is a cap-shaped part 12 projecting inward, and a plurality of solid bodies formed radially on the inner circumferential surface of the bottle from the upper end of the cap-shaped part 12 to the lower part of the body part 10. protruding rib 13,
13,... In addition, the solid protruding ribs 13 in the saturated polyester resin bottle 9
,13. ... are solid protruding ribs 8, 8 . . . on the intermediate material 1 . ... was obtained by subjecting it to biaxial stretch blow molding.

[Action and effect]

The method for producing a saturated polyester resin bottle of the present invention includes a neck portion whose upper end is an open rim, a body portion continuous to the neck portion, and a bottom portion continuous to the body portion whose lower end is a round bottom top portion. The saturated polyester is composed of a bottomed hollow body having a plurality of solid protruding ribs protruding radially from the top of the round bottom toward the bottom end of the body on the inner peripheral surface. By biaxially stretching and blow-molding a resin intermediate material in a blow-molding mold, multiple solid protruding ribs radiating from the center of the bottom of the bottle to the bottom of the body are created on the inner circumference of the bottle. You will get the thin walled bottle that comes with it.

Therefore, in the method for manufacturing a saturated polyester resin bottle of the present invention, from the bottom part, which is most likely to be thinned in biaxial stretch blow molding, to the lower part of the bottle body, a plurality of radial insides extending from the center of the bottom to the lower part of the bottle body are formed. Since a thin-walled bottle made of saturated polyester resin, which is a biaxially stretched blow-molded product with actual ribs protruding from the inner circumferential surface of the bottle, can be obtained, the reinforcing effect of the plurality of solid ribs is of course achieved. , the thinning between adjacent solid protruding ribs corresponds to the biaxiality of the solid protruding ribs protruding from the inner peripheral surface of the intermediate material used to obtain the saturated polyester resin bottle. Because it is restrained by stretching,
This has the effect of providing a saturated polyester resin bottle that also exhibits excellent rigidity.

In addition, the bottle r1 obtained by the method for producing a saturated polyester resin bottle of the present invention has solid protruding ribs protruding from the inner circumferential surface of the bottle that have a reinforcing effect, so that it has a neat appearance and good appearance. It also has the function and effect that a saturated polyester resin bottle can be obtained.

Furthermore, in the method for producing a saturated polyester resin bottle of the present invention, in particular, a cap-shaped part whose inner peripheral surface center part of the bottom protrudes upward is used as a mold for blow molding when performing biaxial stretch blow molding. When using a blow molding mold that is known as A thin-walled bottle made of saturated polyester resin, which has a plurality of solid protruding ribs on the inner peripheral surface of the bottle that project radially toward the lower end, that is, a cap-shaped portion at the center of the bottom of the bottle. The synergistic effect of the structure and the solid protruding ribs on the inner peripheral surface of the bottle provides extremely high resistance to internal pressure.Moreover, the annular part surrounding the cap-shaped part makes it possible to hold the bottle on a horizontal surface. It has the function and effect that a saturated polyester resin bottle with good self-standing stability can be obtained.

In particular, in the case of a bottle in which the center part is a cap-shaped part that protrudes inward, the bottle can be stood up in a stable state, so that the liquid filling can be transferred to the bottle as it is transferred on the belt conveyor. When automatically filling the bottle, the enlarger does not shift from the automatic filling nozzle, and filling defects due to instability of the bottle can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of an intermediate material made of saturated polyester resin used in the method for producing a saturated polyester resin bottle of the present invention, and FIG. 2 is a sectional view showing the production of a saturated polyester resin bottle of the present invention. FIG. 3 is a cross-sectional side view of a part of Example '1 of the bottle obtained by the method, and FIG. 1: Intermediate material, 3: Neck, 4 Body, 5: Round bottom, 6
: Bottom, 7゛ Bottom end of body, 8, 8: Solid protruding rib, 9゛ Saturated polyester resin bottle, 10: Bottle body, 11: Bottom of bottle, 12 Cap-shaped part protruding inward of bottle, 13, 13: Solid protruding rib.

Claims (1)

[Claims] It consists of a neck part whose upper end is an open mouth edge, a body part continuous to the neck part, and a bottom part continuous to the body part and whose lower end is a round bottom top part, and the inner circumferential surface has the above-mentioned An intermediate material made of saturated polyester resin is constructed of a bottomed hollow body in which a plurality of solid protruding ribs protrude radially from the top of the round bottom to the bottom of the body. By heating to a stretching temperature and then biaxially stretching blow molding in a blow mold, a plurality of solid protruding ribs radially extending from the center of the bottle bottom to the bottom of the bottle body are formed around the inner circumference of the bottle. A method for producing a saturated polyester resin bottle, characterized by obtaining a bottle with a thin wall surface.