JP3037060U - Hot runner device for synthetic resin molding with pull top - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To prevent injection of molten resin of unmelted resin at a boundary between a fluidized bed and a solidified bed derived from an internal heating method or a cold runner method, and to effectively prevent defects in the score part due to this. Improvement. SOLUTION: The ring center side of the portion corresponding to the pull tops of cavities A and B formed by a mold that can be opened and closed,
A hot runner device for a synthetic resin molded product having a pull-top, characterized in that a gate 3 provided at the tip of a hot runner 2 having a heating mechanism 11 on the outer periphery is opened to enable uniform injection molding with molten resin. .

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a hot runner device for a synthetic resin molding having a pull top having good moldability.

[0002]

[Prior art]

 Conventionally, an apparatus for molding a synthetic resin molded product having this type of pull-top is a cold runner system that derives from a sprue runner, or a so-called internal heating system that has a heating mechanism in the center and a runner part on the outer periphery. It was either done or was done.

[0003]

[Problems to be solved by the device]

 By the way, the former cold runner system has a problem that the sprue runner is derived and it takes time to cool the material and cool the runner part, so that the molding cycle cannot be shortened. Therefore, the unmelted resin at the boundary of the solidified layer was pulled out, and defects such as flow marks and variations in strength could not be eliminated in the score part (thin part).

Further, there is a problem that a cooling circuit cannot be installed due to the mold structure.

The present invention was made by paying attention to the above points, and provides a hot runner device for a synthetic resin molded product having a good pullability and having a novel pull top capable of shortening the molding cycle. There is.

[0006]

[Means for Solving the Problems]

 The present invention was made to solve the above problems, and could be solved by the following configurations.

(1) A gate provided at the tip of a hot runner equipped with a heating mechanism on the outer periphery is opened at the center of the ring, which corresponds to the pull top of a cavity formed by a mold that can be opened and closed. A hot runner device for synthetic resin moldings with pull-tops, which is characterized by enabling injection molding with uniform molten resin.

(2) A gate provided at the tip of a hot runner equipped with an external heating mechanism is provided at a location corresponding to the opposite side of the center of the ring of the pull top of the cavity formed by the mold that can be opened and closed. A hot runner device for synthetic resin moldings with a pull top characterized by being opened.

(3) In the heating mechanism, chip heaters are provided around the periphery of the body heater gate on the outer circumference of the hot runner, and the temperature is controlled separately or in conjunction with each other. (1) or (2) Hot runner device for synthetic resin moldings with either pull-top described.

[0010]

[Action]

 A cavity that is formed by a mold that can be opened and closed has a space in which a synthetic resin molded product with a pull top can be molded.The hot runner gate is opened at the location corresponding to the pull top or at the opposite side. Therefore, the molten resin in the hot runner injected from this gate is smoothly injection-molded in the cavity.

By the way, since the hot runner is provided with a heating mechanism on the outer periphery thereof, heat can be effectively supplied to the molten resin in the hot runner, and a body heater is provided on the outer periphery of the hot runner. It is possible to perform efficient and efficient runnerless molding operations by controlling the temperature of the chip heaters linked to the gates individually and in conjunction with each other.

[0012]

[Embodiment of the invention]

 The third embodiment of the present invention will be described below.

Each of the embodiments shows an apparatus for molding a synthetic resin molded product targeting various containers equipped with pull-tops, auxiliary caps that can be fixed to openings of bottles, and caps.

First Embodiment FIG. 1 is a vertical cross-sectional explanatory view showing an example of a hot runner device for an auxiliary cap, and FIG. 2 is a perspective sectional view of a molded product molded by the same as above.

The drawings will be described.

Reference numeral 1 denotes a probe body in which a hot runner 2 is vertically passed, and the tip has a conical shape. Reference numeral 3 denotes a gate formed at the tip of the hot runner 2. The gate 3 is a cavity corresponding to an auxiliary cap formed by a large number of molds a, b, c and d opened in the arrow direction shown in the figure. It is opened at the central portion of the central portion 6 beyond the center of the ring portion 5 of the pull top portion 4 of A.

Reference numerals 7 and 8 denote inner and outer holding cylinder portions of the cavity A that can be fitted and fitted into the inside and the outside of an opening of a container, a bottle, and the like, and 9 denotes an inner screw and a screw of another screw cap (not shown). Similarly, the screw portion 10 of the cavity A and the airtight holding cylinder portion of the cavity A, which can closely maintain the airtightness by closely contacting the inner top of the screw cap, respectively.

Reference numeral 11 denotes a heating mechanism such as a coil heating wire arranged on the outer circumference of the hot runner 2. A body heater 11a is arranged at the upper part of the hot runner 2 and a chip heater 11b is arranged at the tip part thereof. It can also be installed. Reference numeral 12 denotes the temperature detecting element, which is designed so that the temperature of the heating mechanism 11 can be set and the temperature of the body heater 11b and the chip heater 11b can be controlled. The body heater 11a can be varied in its winding number density such that it is dense in the upper and lower portions and sparse in the central portion as shown in the figure.

Reference numeral 13 is a manifold, 14 is a gap formed on the outer periphery of the probe body 1, and 19 is a cooling circuit. The auxiliary cap X, which is the molded product of FIG. 2, has a configuration of a pull top portion 4a, a ring portion 5a, a central portion 6a, inner and outer sandwiching tubular portions 7a and 8a, a screw portion 9a, and an airtight holding tubular portion 10a.

The operation will be described based on the above configuration.

The molten resin injected by a synthetic resin melting injection mechanism (not shown) passes through the manifold 13 and the hot runner 2 of the probe body 1 to be injected into the cavity A from the gate 3.

By the way, since the hot runner 2 is always kept at an appropriate temperature by the heating mechanism 11 on the outer periphery, it is always injected into the cavity A through the hot runner 2 every injection operation.

Therefore, the molten resin injected from the gate 3 passes over the ring portion 5 of the pull-top portion 4 and smoothly moves to each portion where the cap can be formed from the central portion of the central portion 6 thereof. It is possible to get around and obtain the cap X shown in FIG.

Since the runnerless molding operation is performed in this embodiment, the molding cycle can be shortened.

In particular, the hot runner method by heating from the outer periphery eliminates unmelted resin, can eliminate defects in the score part, and can miniaturize the probe, which has many effects.

(Second Embodiment) FIG. 3 shows a hot runner device for molding an auxiliary cap for a pull top. Therefore, in the configuration of FIG. 1, the cavity A is turned upside down and the pull top part 4 is arranged downward. However, only the gate 3 is made to face the central portion of the central portion 6 on the opposite side of the pull-top portion 4, and other configurations are substantially the same as those of FIG. 1 and are not different.

Therefore, the same components as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted. Similarly, the molded product of FIG. 4 is assigned the same reference numeral as that of FIG. 2 and its detailed description is omitted.

(Embodiment 3) This embodiment shows a cap forming apparatus having a pull top as shown in FIGS. 5 and 6, and is a cavity for an auxiliary cap with a pull top of FIG. A configuration in which a cavity configuration for the main cap is additionally attached to the configuration is shown.

Therefore, the cavity structure for the auxiliary cap with the pull top and the probe body structure are slightly different from those of FIG. 1 in the presence or absence of the screw portion 9 of the cavity and the like, but both are substantially the same. Therefore, the same components will be denoted by the same reference numerals, the description thereof will be omitted, and only new components will be described below.

Reference numeral H denotes a heat pipe having a built-in heat generating wire, which is vertically mounted in a cylindrical mold 15 and is flexible at the tip thereof with the outer clamping cylinder portion 8 of the cavity A between the mold 15 and the mold d. A cavity B for the main cap is formed in communication with the cavity A through the connecting piece portion 16. Reference numeral 17 denotes the inner cylinder portion 18 of the cavity B corresponding to the airtight holding cylinder portion 10, and similarly, the claw hook portion of the cavity B.

With the above configuration, the molten resin injected from the gate 3 moves from the cavity A to the cavity B in a uniform heat-temperature distribution flow state to obtain a molded product with extremely high moldability. be able to.

In addition to the configuration of the auxiliary cap X molded in FIG. 1, the rising portion 20a, the hook portion 18a of the main cap Y, and the inner tubular portion 17a are connected via the flexible connecting piece portion 16a as shown in FIG. Can be molded.

It should be noted that G shown in each of the embodiments indicates a gate mark.

[0034]

[Effect of the invention]

 According to this invention, the hot runner structure is an external heating system, and the heat transfer means operating in the center direction effectively works, so that the generation of undesired resin such as unmelting or incompleteness disappears, and the center of the pull top is eliminated. Since the molten resin can be reasonably moved from the part to the entire cavity, molding defects can be eliminated, and defects such as flow marks and strength variations in the score part, that is, the thin part, can be eliminated.

Further, since the resin can flow into the cavity from the back side, the cooling circuit can be installed.

By controlling the heating mechanism with the body heater and the chip heater, runnerless molding can be performed, which has the effects of inexpensive mass production and shortening of the molding cycle.

[Brief description of the drawings]

FIG. 1 is an overall explanatory sectional view showing an example of a hot runner device for a synthetic resin molded product having a pull top according to the present invention.

FIG. 2 is a cross-sectional view of a slope of a molded product molded by the same as above.

FIG. 3 is an explanatory cross-sectional view of a main part showing another embodiment of the present invention.

FIG. 4 is a sectional view of a slope of the above-mentioned molded product.

FIG. 5 is an explanatory cross-sectional view of a main part showing still another embodiment of the present invention.

FIG. 6 is a perspective view of the above molded article.

[Explanation of symbols]

 1 Probe Main Body 2 Hot Runner 3 Gate 4 Pull Top Part 5 Ring Part 11 Heating Mechanism 11a Body Heater 11b Chip Heater A, B Cavity G Gate Trace

Claims (3)

[Utility model registration claims] 1. A uniform melt is formed by opening a gate provided at the tip of a hot runner equipped with a heating mechanism on the outer periphery at the center side of the ring, which corresponds to the pull top of a cavity formed by a mold that can be opened and closed. A hot runner device for a synthetic resin molded product having a pull-top, which is characterized by being capable of injection molding with resin. 2. A gate provided at the tip of a hot runner having an external heating mechanism is opened at a location corresponding to the side opposite to the center of the ring of the pull top of the cavity formed by a mold that can be opened and closed. A hot runner device for synthetic resin moldings with a pull top characterized by being made. 3. The pull-top according to claim 1, wherein the heating mechanism is provided with chip heaters around the periphery of the body heater gate on the outer periphery of the hot runner, and the temperature is controlled separately or in conjunction with each other. Hot runner device for synthetic resin moldings.