JPS60264223A - Molding method of plastic container having female thread at opening portion - Google Patents

Abstract

PURPOSE:To enable simultaneous monolithic molding of a plastics container having a female thread, by a method wherein blow molding is performed by arranging a female-threaded parts having a thin protrusion on the external circumference on a molding position of an opening of the container in a parison, and simultaneously with the molding of the container fusion bonding and fixation of the female-threaded parts to the opening are performed by melting the thin protrusion by heat at the time of the blow molding. CONSTITUTION:Cylindrical female-threaded parts 1 made of thermoplastic plastics having a threaded part 1a and having thin protrusion 1b and unevenness 1c on the external circumference is arranged on a forming position of an opening of a container in a space between molds 2, 2. Then a parison 3 extruded through an extruding machine 4 is placed immediately between the molds 2, 2, compressed air is blown into the parison 3, successively, a through an air blowing pipe 5, the parison 3 is made into a container form and the container is obtained by performing demolding after cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a blow molding method for a plastic container having a female thread in the opening.

(Prior art) Plue molding is a method in which thermoplastic plastic is extruded into a tube shape (this tube is called a parison =), which is immediately sandwiched between molds and a sudden blast of air is blown into the inside to form a hollow product. The reality is that most plastic containers such as bottles are formed using this method.

(Problem to be solved by the invention) However, in blow molding, the outer surface of the parison is placed inside the mold. Because it is pressed into a predetermined shape, it is not easy to mold a product with a thread (female thread) on the inner surface of the parison, that is, on the inner circumference of the container.

The present invention solves the above-mentioned problems in blow molding, and aims to provide a method for obtaining a plastic container having a female thread at the mouth by blow molding.

(Means for Solving the Problems) The present invention provides a sieve-shaped female screw part made of thermoplastic plastic, having a pheasant part on the inner periphery, and a thin protrusion on the outer periphery, inside a parison during blow molding of a container. The mouth part is formed by blow molding, melting the thin protrusion by the heat during blow molding, and fusion-fixing the female screw part to the container mouth part at the same time as the container molding. Open the plastic container with one that has a female thread. This will be explained in detail below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing the positional relationship of the gold molding during blow molding.

As shown in FIG. 2, the inner periphery has a threaded portion 1a, and the outer periphery has a threaded portion 1a.
A sieve-shaped female screw part 1 made of thermoplastic plastic having a thin protrusion 1b with a thickness of 02 to 0.2a+ and an unevenness 10
As shown in Figure 1, gold J! has a container-shaped cavity.
A parison 6t made of thermoplastic plastic such as polyethylene is extruded from the extruder 4 so as to cover the female screw part 1, and the parison 6 is placed in the forming position of the container opening between M2. Immediately, compressed air is blown into the parison 6 from the air blowing pipe 5, the parison 61L is brought into close contact with the cavity surface of the mold 2.2 to form a container, and after cooling, the dust is removed and the shape shown in FIG. A container with a button in the perspective view and the sectional view in FIG. 4 taken along the cutting line A-All in FIG. 6 is obtained.

Note that the female screw component 1 is made of thermoplastic plastic such as hard vinyl chloride resin and can be easily molded by injection molding. Further, the irregularities 10 on the outer periphery are intended to more securely fix the container to the mouth of the container, and can be removed when unnecessary.

In the illustrated example, the female threaded part 1 was placed at the container mouth forming position by fixing the female threaded part 1 to the tip of the air blowing pipe 5. It may be supported.

(Function) The function of the present invention is to melt the thin protrusion 1b on the outer periphery of the female threaded part 1 placed at the container opening forming position in the parison 6 by the heat during blow molding, and to open the female threaded part 1 at the same time as the container is formed. The method is to fuse and fix the parts to the parts. At this time, if the outer periphery of the female threaded part 1 has irregularities 10, the fixation becomes even stronger.

(Effects) 6. Molding method of the present invention, from thermoplastic plastics 9.
A female threaded part having a threaded part on the inner periphery and a thin protrusion on the outer periphery is placed in the parison at the position where the opening of the container is formed, and is blow molded, and the thin protrusion T-# is melted by the heat during blow molding. The female screw part is fused and fixed to the mouth part at the same time as the container is formed.

In this way, the present invention has made it possible to simultaneously and integrally mold a dessic spring device with a female screw, which was previously considered difficult, by using the rational method of blow molding.

[Brief explanation of drawings]

The drawings relate to the present invention, and include a partially cutaway perspective view showing the positional relationship of the metal cape during No. 11 Hiro-pro molding, Figure 2 is an IM view of the female threaded part, and Figure 6 is a diagram showing the positional relationship of the metal cape during No. 11 Hiro-pro molding. FIG. 4 is a perspective view of the nine containers obtained, and a sectional view of the container cut along the line 41A-A in FIG. 6 of FIG. In the figure, 1 is a female screw part, 2 is a mold, 6 is a parison, 1a
1b is a thin protrusion. Patent applicant Inoue MBC Co., Ltd. 4- Figure 2 Figure 3-119- Figure 4

Claims (1)

[Claims] P1 made of thermoplastic plastic has a threaded part on the inner periphery,
A sieve-shaped female threaded part having thin protrusions on the outer periphery is placed at the container opening forming position in the parison during blow molding of the container, and the thin protrusions are melted by the heat during blow molding, forming the container. 1. A method for molding a plastic container having a female thread in one mouth part, characterized in that the female threaded part (T) is fused and fixed to the container mouth part at the same time as molding.