JPS634773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing a deformed hollow molded product, and more particularly to a method for manufacturing a hollow molded product having uneven additional parts such as protrusions.

Prior Art Conventionally, when manufacturing a hollow product 2 having a protrusion 1 as shown in FIG. A method was adopted in which the protrusion 1 formed by this method was secondarily fixed. However,
In such a method, the process is divided into several steps, resulting in a significant decrease in productivity, and the basic advantage of the blow molding method, which is high productivity, is not utilized.
On the other hand, it is also possible to manufacture the protrusion 1 integrally with the main body 2' by blow molding, but in this case, in order to extend the parison to the protrusion 1,
Before clamping the mold, pressure fluid is blown into the inside of the parison to inflate the parison to a certain extent, and then the mold is clamped to perform blow molding. However, the above method has the disadvantage that the parison expanded during mold clamping is cut off all around the joint surface of the mold, resulting in significant material loss and requiring much effort to remove burrs afterwards. Another method is to partially expand and expand the parison to limit the part that is eaten away, but it is extremely difficult to partially change the hardness and wall thickness of the parison due to the balance with the melt index of the parison. It is. In addition, when a screw hole or the like is provided in the protrusion 1 to connect it to another member, the protrusion 1
In addition to the strength itself, the bonding strength between the protrusion 1 and the main body 2' is also required to be high, but the third method has a problem in that the desired bonding strength cannot be obtained.

Purpose The present invention has been made in view of the above points, and is a method for manufacturing a hollow molded product having a protrusion that has good productivity, reduces material loss, and has a high bonding strength between the protrusion and the main body of the hollow molded product. The purpose is to provide

Configuration The present invention includes a step of supplying a molten raw material to a concave portion corresponding to the protrusion of a first mold of a hollow molded product having a protrusion, and a step of supplying a molten raw material to another concave portion of the first mold. A protrusion comprising the steps of supplying a parison, clamping the first mold and at least one second mold, and blowing pressurized fluid into the parison. This is a method for manufacturing a hollow molded product.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. The method of the present invention will be explained with reference to a blow molded product manufacturing apparatus illustrated in FIG.

The hopper 3 stores raw materials for hollow molded products, a conduit 4 is connected to the lower part of the hopper 3, and an extrusion nozzle 5 is provided at the other end of the conduit 4. is august cryu 6
is rotatably inserted therein, and furthermore, a heater band 7 is wrapped around the outer periphery of the conduit 4. Therefore,
The raw material in the hopper 3 enters the conduit 4 and is conveyed to the extrusion nozzle 5 by the auger screw 6 etc., but since this path is heated by the heater band 7, the raw material in the conduit 4 is in a molten state. Maintained.

For example, as shown in FIG. 3, the molten raw material 8 is injected from the sub-conduit 4a into the protrusion groove 10a of the first mold 9 shown in FIG. The injection amount in this case can be adjusted, for example, with the valve 4b.
It is necessary to set it so that it is at least larger than the capacity of the protrusion 1 of the product. Note that this injection step can also be performed manually.

Next, as shown in FIG. 3, the melted raw material 8 enters the extrusion nozzle 5 from the conduit 4, passes through a cylindrical flow path constituted by an outer die 11 and an inner die 12, and leaves the extrusion nozzle 5 through the cylindrical A parison 13 of the shape is poured out. This parison 13 is the fifth
As shown in the figure, it is stored in the groove 10 of the first mold 9.

Next, the first mold 9 and the second mold 14 are aligned in the direction of the arrow in FIG. 5, respectively, and the molds are clamped. During this mold clamping, the portions of the mass 8 of the raw material contained in the grooves 10a of the protrusions that protrude from the mold become burrs due to the mold clamping.

Next, pressurized fluid is blown into the parison 13,
The parison 13 is pressed against the molds 9 and 14 by the pressure of the pressurized fluid. For this reason, the lump 8 of raw material of the protrusion 1 and the parison 13 are made of the same material and are therefore completely integrated. After this, the mold is released and cooled, for example, at room temperature, to obtain a hollow molded product having protrusions.

Effects As explained in detail above, according to the manufacturing method of the present invention, it is possible to manufacture a hollow molded product having a protrusion through a series of steps, and the molten raw material is separately stored in a part corresponding to the protrusion of the mold. Since the material is molded in a single step, material loss is extremely small, and it can be manufactured without requiring excessive effort to remove burrs. Furthermore, since the hollow molded product main body and the protrusion of the hollow molded product having the protrusion are integrally formed from the same material, the bonding strength between the protrusion and the main body is extremely high, and the screw hole etc. can be easily inserted into the protrusion. It is possible to drill holes in the hole and screw other objects onto it. Furthermore, even if a load is applied to the joint between the protrusion and the main body, unlike conventional molded products manufactured by secondarily fixing the protrusion to the main body of the hollow molded product, the protrusion remains attached to the main body. There will be no departure from.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a hollow molded product having a protrusion;
Fig. 2 is a schematic diagram of a manufacturing apparatus for producing a hollow molded product, Fig. 3 is an explanatory diagram illustrating the formation of a parison and the supply of molten raw material to the protrusion of the mold, and Fig. 4
The figure is a plan view of the first mold, and FIG. 5 is an explanatory diagram illustrating the process of aligning the second mold with the first mold in which the parison and lumps of raw material are housed and performing mold clamping. . (Explanation of symbols), 1: Projection, 2: Hollow molded product,
5: extrusion nozzle, 8: raw material mass, 9: first mold, 13: parison, 14: second mold.

Claims (1)

[Claims] 1. A step of supplying a molten raw material to a recess corresponding to the protrusion of a first mold of a hollow molded product having a protrusion, a step of storing a parison made of the raw material in the first mold, and a step of storing a parison made of the raw material in the first mold. Clamping the mold and at least one second mold;
A method for manufacturing a hollow molded product having a protrusion, the method comprising the step of blowing pressurized fluid into the parison.