JPS5931446B2 - Molding method for molded products with inserts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a molded article having an insert.

Conventionally, synthetic resin molded products with embedded inserts have been molded by a method in which the insert is placed in advance in the mold cavity of an injection mold, and then molten resin is injected into the mold cavity. Ta.

However, in the conventional method, the insert placed in the mold cavity is moved from a predetermined position by the force of the molten resin injected into the mold cavity.

To prevent this, the mold is equipped with an insert suction mechanism consisting of an air flow passage and a vacuum pump, or a leg body is attached to the insert to support the gap between the insert and the separately molded wall inside the mold cavity. It is necessary to take measures to secure the product, which reduces molding costs. It was difficult. The present invention has been made to solve the problems of the conventional methods as described above.

Next, one embodiment of the method of the present invention will be described in detail with reference to the drawings.

The drawing shows an example in which the method of the present invention is applied to the molding of a storage container for a rolled sheet for packaging foods, etc. In the drawing, 1 is a molded product body consisting of a container in which the rolled sheet is stored. The molded product main body 1 is made from a container having a substantially arcuate cross section and a side edge 3 opposite to the side edge to which the lid 2 is attached extending horizontally in the form of a tongue. The molded product member 4 is made up of a molded product member 4 and another molded product member 6 that is connected to the upper surface of the side edge 3 of the molded product member 4 so as to be openable and closable via a hinge 5 made of a thin wall. , 6 are molded into a body by injection molding using polypropylene resin.

The molded product member 6 in the molded product main body 1 obtained in this way normally stands upright on the side edge 3 of the molded product member 4 as shown in FIG. 1, that is, the state when injection molded. However, in the following situation, the insert T used as a cutter is placed on the cutter mounting step 8 provided on the upper surface of the side edge 3, and the insert T is attached to the molded product member. 4 and 6, close the molded parts 4 and 6 using the hinge 5, and insert the insert □
to hold. Thereafter, in the sandwiched state, the side edge 3 of the molded product member 4 and the molded product member 6 are high-frequency welded to obtain a molded product having the desired insert T as shown in FIG.
The circumference 9 has a plurality of 'J'L's extending in the longitudinal direction of the cutter □, and the side edge 3 of the molded product member 4 melted by high frequency when the insert T is fixed is directly welded to the molded product member 6. This ensures that the insert □ is securely fixed. Further, the lid body 2 may be molded separately or may be molded integrally with the molded product member 4, which is a container. In the method of the present invention, the insert fixed to the molded product body may be partially buried in the molded product body and the remaining part exposed outside as in the above embodiment, or it may be completely embedded within the molded product body. For example, when molding a synthetic resin paperweight with a metal lump 11 built in as an insert as shown in FIG. Two molded parts 14 and 15 formed with 13
A molded product main body 17 having a structure in which the two are connected via a hinge 16 consisting of a thin wall portion is integrally molded from synthetic resin, and a metal lump 11 is fitted into one recess 13 of the obtained molded product main body 17. The molded product members 14 and 15 are closed to sandwich the metal lump 11, and then the molded product member 1 is heated from the outside by high frequency heating.
It is only necessary to weld the mutually abutting surfaces of 4 and 15.

As for the structure of the molded product body used in the method of the present invention, the number of molded product members connected via a hinge made of a thin wall portion is changed as appropriate depending on the shape of the insert.

In the method of the present invention, the insert can be held between the molded product members by pressing it by hand using a hinge made of a thin wall, or by fixing the insert to the molded product body in a subsequent process. If, for example, heat welding is performed using a high-frequency heating machine, the mechanical force used in the subsequent process, such as pressing with a heating rod of the high-frequency heating machine, may be used as is.

In the method of the present invention, a heat welding method using heat, high frequency, ultrasonic waves, etc. is mainly used to fix the insert to the molded product body. Alternatively, fitting recesses may be integrally provided on the other side, and the fitting recesses may be fitted when the molded parts are closed.

The synthetic resin that forms the molded product body is a thermoplastic synthetic resin with a regular molecular arrangement, such as isotactic polypropylene, because it has a structure in which multiple molded product components are connected via hinges made of thin parts. is suitable. In the method of the present invention, the molding of the molded product body and the embedding of the insert are performed in separate processes, so there is no need to provide a complicated means for fixing the insert in the injection molding machine or the mold, and the mechanism is simplified. Since there is no need to place an insert in the mold each time the product is molded, the time required to form the main body of the molded product is shortened.

In addition, the insert is held between the molded product members using a hinge made of a thin part, and the force method is used to fix the insert to the molded product body in the sandwiched state.
It is easy to fix the insert in the desired position, and the quality is uniform.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the method of the present invention, FIG. 2 is a partially cutaway sectional view of a molded product molded by the same method, and FIG. 3 is a cross-sectional view of a molded product molded by the method of the present invention. FIG. 2 is a sectional view showing a molded product. Explanation of symbols 1, 17... Molded product body, 4, 6
, 14, 15... Molded product member, 5, 16...
・・Hinge consisting of Confucian meat part, 7, 11・・・・Insert.

Claims (1)

[Claims] 1. A molded product body having a structure in which a plurality of molded product members are connected via a hinge made of a thin wall portion is integrally molded with synthetic resin, and an insert is inserted between the molded product members of the obtained molded product body. A method for molding a molded product having an insert, characterized in that the insert is held between molded product members, and the insert is fixed to the molded product body in the sandwiched state.