JP3490884B2 - Method of manufacturing synthetic resin container - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the use of PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) or a mixture thereof or PP (polypropylene) as a raw material. The present invention relates to a method for manufacturing a synthetic resin container in which a detachably formed lid can be mounted. 2. Description of the Related Art In general, the container portion of a synthetic resin container with a lid, such as a laver container, is formed by so-called direct blow molding in consideration of production costs. As is well known, in the direct blow molding, since a molded product is obtained by blowing air into a parison extruded in a predetermined mold in a hanging state, there is an advantage that a lightweight and inexpensive hollow container can be mass-produced to a considerable extent. [0003] However, the direct blow-molded container is inferior in quality, strength, and mass productivity such as transparency as compared with a uniaxial or biaxial stretch blow-molded container using a preform. can not deny. On the other hand, in stretch blow molding using a preform, a large amount of equipment and costs are required for molding a preform corresponding to a synthetic resin container having a desired shape, regardless of the case where a standard preform widely used is used. There are drawbacks. for that reason,
Conventionally, for example, in the case of shampoo containers, etc., a direct blow-molded container was used at the beginning of the launch of a new product, and a special preform was used after a considerable degree of sales prediction was possible in view of market reactions Measures have been taken in consideration of the production cost of containers, such as switching to uniaxial or biaxial stretch blow-molded containers. [0004] As described above, in order to mass-produce containers of the same shape having excellent quality and strength, it is optimal to use stretch blow molding using a preform. However, due to cost or equipment, at the beginning of the shipment of new products, direct blow molded products with inferior quality and strength were inevitably used. The present invention provides a method of mass-producing a low-cost mass-production of a synthetic resin container having an arbitrary shape excellent in quality and strength, particularly a synthetic resin container having a detachable lid, using a standard preform. Is what you do. SUMMARY OF THE INVENTION The present invention is directed to a stretch blow molding using a preform, wherein a fitting portion with a lid is formed in a body of a container, and the fitting portion is formed after molding. A method for producing a synthetic resin container, characterized in that the container is cut at an upper side. That is, according to the present invention, a fitting portion for a separately manufactured lid is formed in the body of a molding die for a synthetic resin container such as PET which is generally used.
After uniaxial or biaxial stretch blow molding using a preform, cut and separate vertically above and below the fitting part, and adopt only the lower side including the bottom as a product, while discarding or reusing the upper side. did. Therefore, if a molding die is replaced, a synthetic resin container with an arbitrary diameter, depth, and shape can be stretched, which is a high-quality, high-strength, and low-cost container manufacturing method compared to direct blow molding. It became possible to manufacture using blow molding. Hereinafter, a method of manufacturing a synthetic resin container according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of a standard preform 1 for a PET bottle having a capacity of 2 liters, which is commonly used. In the present invention, as described above, various kinds of raw materials such as PET, PEN or a mixture thereof or PP can be used, and any preform having various shapes can be used. In particular, when trying to obtain a deep-bottomed container which is difficult to form with a uniform thickness by direct blow molding, a particularly excellent effect can be exhibited. FIG. 2 is a front view showing a state where the preform of FIG. 1 is formed into a bottle shape by performing biaxial stretch blow molding. In the method for manufacturing a synthetic resin container according to the present invention, a fitting portion 4 for fitting to a lid used for a completed container is formed in a body 3 below the shoulder 2 of the synthetic resin container formed into a bottle shape. deep. The fitting portion 4 may have any structure such as a screw (screw cap) type shown in FIG. 2 and a stopper type. The diameter of the fitting portion 4 depends on the preform to be used. However, the diameter of the fitting portion 4 basically ranges from a small diameter of about the same as the diameter of the preform to a large one shown in FIGS. It is possible to set the height and shape. When performing blow molding, it is desirable to form a guide portion 5 of the cutter above the fitting portion 4 in order to facilitate the cutting operation after molding. By cutting the bottle-shaped container up and down by applying a blade to the gutter guide portion 5, the lower bottomed container 7 is commercialized as a desired synthetic resin container. The cutting may be performed by an automatic robot. FIG. 3 is a front view showing a state where the molded synthetic resin container is cut and separated vertically. The upper remnants 6 that have not been adopted as a product can be discarded or dissolved, re-formed into a standard preform or the like, and reused. According to the method of manufacturing a synthetic resin container according to the present invention, although it depends on the capacity of the molding machine, for example,
Approximately 1,500 pieces can be produced per hour using individual molding dies. This corresponds to about 4 to 5 times the production capacity of a normal direct blow molded product. According to the present invention, it is possible to obtain a synthetic resin container having an arbitrary diameter, depth and shape by simply changing the mold, as compared with direct blow molding. In addition, the container can be manufactured using uniaxial or biaxial stretch blow molding, which is a method for manufacturing a high-strength and low-cost container. That is, if a desired synthetic resin container is to be obtained only by stretch blow molding using a preform, it is necessary to use a preform suitable for the caliber and structure, which is a great deal of work for molding the preform itself. Although equipment and costs are required, according to the method for manufacturing a synthetic resin container according to the present invention, only a low-cost blow molding die is prepared compared to a preform molding die, and a standard preform is used. Thus, synthetic resin containers of various shapes can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a standard preform for PET bottles. FIG. 2 is a front view of a container in which a standard preform is biaxially stretch blow-molded with a molding die. FIG. 3 is a front view showing a state where a molded container is cut and separated vertically. [Description of Signs] 1 Preform 2 Shoulder 3 Body 4 Fitting part 5 Gutter guide

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-221220 (JP, A) JP-A-5-213385 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 49/00-49/81

Claims (1)

(57) [Claims 1] At the time of stretch blow molding using a standard preform, a screw cap serving as a lid is formed at the body of the container.
A screw is formed as a fitting portion with the
A method of manufacturing a synthetic resin container, wherein a guide portion of a cutter is formed on the upper side of the container, and after molding, the guide portion is cut by a guide portion of the cutter above the fitting portion.