JPH0233508B2 - KOKATSUSEISOSEIEKINYORUSHASHUTSUSEIKEIKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection molding machine using a highly active composition liquid.

Injection molding machines are widely used, which inject a highly active composition liquid containing a mixture of at least two types of reactive raw materials into a mold, and react and solidify the composition liquid in a short time to produce a molded product in a desired shape. There is. For example, catalyst,
A highly active composition liquid, which is a mixture of a polyol such as polyester or polyether mixed with a crosslinking agent, a blowing agent, etc., and an organic isocyanate compound, is injected into the cavity of the mold while or immediately after mixing, and the composition is Injection molding machines are known that react, foam, and solidify a liquid in a cavity, and then remove it from a mold to produce a foamed polyurethane molded product.

To briefly explain an example of a conventional injection molding machine with reference to FIG. 1, an upper mold 1 and a lower mold 2 are tightly attached to each other by a hinge part 3 provided at the side end so that they can be opened and closed. Cavity 4 is formed. An injection head insertion hole 6 having a conical lower part is bored in the upper injection part 5 provided protruding from the side wall of the upper mold 1, and a lower injection part 7 provided protruding from the side wall of the lower mold 2 is provided with an injection head insertion hole 6 having a conical lower part. A runner 8 having a U-shaped cross section is cut, and this runner 8
is communicated with the cavity 4 through a pre-drawn gate 9 provided in the lower mold 2. By tightly pressurizing the injection head 11, which is movable up and down and has a sprue 10 in the center, into the head insertion hole 6, a predetermined amount of the foaming highly active composition liquid passes through the runner 8 and the gate 9 into the cavity. The highly active composition liquid is reacted and solidified in the cavity 4, and after solidification is completed, the upper mold 1 is opened and the foamed molded product is taken out from the cavity 4.

In the manufacturing process of the above-mentioned molded product, the highly active composition liquid injected into the cavity 4 is gelled in a short time by reaction, expanded by foaming, filled into the cavity 4, and solidified. However, if the injection head 11 is removed from the injection head insertion hole 6 before the molded product is solidified, the semi-solid substances in the softened runner 8 and gate 9 will be removed from the injection head insertion hole 6. This backflow causes a concave portion, that is, a coplus phenomenon, in the vicinity of the gate 9 of the molded product, and the quality of the molded product becomes partially non-uniform. Therefore, the injection head 11 must be kept inserted into the injection head insertion hole 6 under high pressure until the molded product is completely solidified. In particular, in the case where a large number of molds and one injection head are arranged and a large number of molded products are manufactured continuously by moving one of them in a relative manner, the unit of the injection head 11 is Long cycle times result in reduced production efficiency.

In order to solve the above-mentioned problem, the present invention provides a means for closing the injection passage by being activated after the highly active composition liquid is injected into the cavity from the injection head.

That is, the present invention provides an injection molding machine having an injection passage whose one end communicates with a cavity formed in a mold, and an injection head insertion hole which communicates with the other end of the injection passage. An injection molding machine using a highly active composition liquid, characterized in that it is provided with means for injecting the highly active composition liquid into a cavity from a pressurized injection head through an injection passage and then being activated to close the injection passage. It is.

Embodiments of the invention will be described below with reference to the drawings. Note that the same parts as in FIG. 1 are designated by the same reference numerals.

Example 1 In FIG. 2, the runner 8 formed on the lower mold 2
A closing rod groove 12 is cut out to open at the side end of the lower injection part 7, and the protruding end of the closing rod 13, which is slidably and tightly inserted into the closing rod groove 12, is inserted into the fluid pressure mechanism 14. It is connected to the piston 15. After the injection head 11 is tightly pressed into the injection head insertion hole 6 and injects a predetermined amount of highly active composition liquid from the sprue 10 into the cavity, the fluid pressure mechanism 1
4 to advance the closing rod 13 to close the lower surface of the injection head insertion hole 6 and the runner 8, and at the same time move the injection head 11 upward.
After the highly active composition liquid in the cavity 4 reacts and the molded product is completely solidified, the fluid pressure mechanism 14 is operated in the opposite direction to move the closing rod 13 back and open the lower surface of the injection head insertion hole 6. . Note that the runner 8 and the closing rod 13 may have a rectangular cross-sectional shape. In Example 1, most of the runner 8 can be closed with the closing rod 13, so less highly active composition liquid is required, and the runner can be easily cleaned after taking out the molded product.

Embodiment 2 In FIG. 3, a closing rod hole 16 coaxial with and having approximately the same diameter as the head insertion hole 6 is bored in the lower injection part 7, and a cylindrical closing rod 17 is rotated in the closing rod hole 16. can be secretly inserted at will. At the upper end of the closing rod 17,
As shown in FIG. 4, a notch 18 having the same shape as the end of the runner 8 is formed, and the lower part of the closing rod 17 is connected to a fluid pressure rotation mechanism 19 that can rotate forward and backward. After the injection head 11 is tightly pressurized into the injection head insertion hole 6 and the highly active composition liquid is injected into the cavity 4 from the sprue 10, the fluid pressure rotation mechanism 19 is activated to rotate the closing rod 17. to close the lower surface of the head insertion hole 6 and the runner 8. After the molded product in the cavity is completely solidified, the fluid pressure rotation mechanism 19 is operated in the opposite direction to rotate the closing rod 17 in the opposite direction, thereby opening the lower surface of the head insertion hole 6.

This second embodiment has more leakage when the runner is closed than the first embodiment, but on the other hand, the modification cost is slightly lower.

In the above embodiments 1 and 2, the vertical operation of the injection head and the operation of the fluid pressure mechanism are linked to each other,
Needless to say, it is automatically and continuously produced.

Further, the structure of the present invention is not limited to the above embodiment. For example, the runner in the example was a groove cut into the upper surface of the lower mold, and the injection passage was formed by making the upper mold contact the lower mold, but the runner was formed on the side wall of the lower mold. An injection passage may be provided therethrough. In this case, the lower mold may be omitted and the cavity opening on the upper surface of the lower mold may be sealed with something else, such as an injection molding machine for direct soles of shoes.

The highly active composition liquid used in this invention is not limited to the raw materials for producing polyurethane described above, but can also be used for liquid injection molding of epoxy resins, nylon 6 block copolymers, which have recently been developed, and silicone rubber. Can be used.

As described above, the present invention provides a means for injecting a highly active composition liquid into a cavity from an injection head that is tightly pressurized into an injection head insertion hole through an injection passage, and then is activated to close the injection passage. Since the injection head can be moved to another location as soon as the injection passage is blocked, the operation cycle of the injection head is shortened, and as a result, production efficiency is improved. For example, in the absence of conventional closure means, one work cycle would have taken 90 seconds, with a composition liquid injection time of 3 seconds, molded product solidification time of 80 seconds, and a mold movement time of 7 seconds. Since the solidification time mentioned above is omitted, one working cycle is shortened to 10 seconds, and production efficiency is improved nine times.

[Brief explanation of drawings]

Fig. 1 is a vertical cut side view showing the structure of a conventional injection molding machine, Fig. 2 is a vertical cut side view showing the main parts of Embodiment 1 of the present invention, and Fig. 3 shows the main parts of Embodiment 2. FIG. 4 is a vertical section side view, and FIG. 4 is a plan view cut along the - line of FIG. 1: Upper mold, 2: Lower mold, 4: Cavity, 6: Injection head insertion hole, 8: Runner, 11: Injection head, 12, 16: Closing rod groove, 13, 17: Closing rod, 14, 19: Fluid Pressure mechanism, 18: Notch.

Claims (1)

[Scope of Claims] 1. An injection molding machine having an injection passage whose one end communicates with a cavity formed in a mold, and an injection head insertion hole which communicates with the other end of the injection passage,
A highly active composition is provided with a means for injecting a highly active composition liquid into the cavity from the injection head tightly pressurized into the injection head insertion hole through the injection passage, and then is operated to close the injection passage. Injection molding machine using active composition liquid. 2. Claim 1, wherein the means for closing the injection passage is a closing rod that is slidably inserted tightly into a closing rod groove formed by extending a runner provided on the lower die and is operated by a fluid pressure mechanism. An injection molding machine using the highly active composition liquid described in 2. 3. The means for closing the injection passage is rotatably inserted tightly into the closing rod hole formed coaxially with the injection head,
2. An injection molding machine using a highly active composition liquid according to claim 1, wherein the closing rod has a notch formed at an upper end in substantially the same shape as the injection passage.