JPH1177809A - Method for double-layer injection blow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable manufacture of a globe for an electric bulb which is comfortable for the eyes and low cost. SOLUTION: In this method for molding, a parison for an insert being molded of first resin and having a gate hole formed in a prescribed place is set in a cavity mold and a cavity space is formed by opposing a core mold to the cavity mold. A double-layer parison is molded by filling the cavity space with second resin through the gate hole. Then, the core mold is opposed to a blow mold and compressed air is blown in so as to inflate the double-layer parison. By molding a globe 12 for an electric bulb with the first resin colored more deeply than the second resin, it is made comfortable for the eyes, since the front part 52 of the globe 12 for the electric bulb is colored deeply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layer injection blow molding method.

[0002]

2. Description of the Related Art Conventionally, as a lighting device for a house, particularly for a bathroom, a globe for a light bulb has been provided in which the amount of light is adjusted by a two-layer structure so as not to irritate the eyes.
The bulb globe is usually formed of glass or plastic, and the bulb bulb made of glass is formed by hot welding two globe parts made of differently colored glass materials. Further, the plastic bulb globe is formed by molding two globe parts by injection molding and joining the two globe parts.

[0003]

However, in the above-mentioned conventional bulb glove, the bulb bulb made of glass is formed by hot work, which not only increases the cost but also makes it vulnerable to impact. Fragile. On the other hand, plastic bulb gloves have a limited resin flow length during injection molding. Will be higher.

An object of the present invention is to provide a two-layer injection blow molding method capable of solving the problems of the conventional bulb globe and producing a bulb bulb that is easy on the eyes and low in cost. I do.

[0005]

For this purpose, in a two-layer injection blow molding method according to the present invention, a parison for an insert molded with a first resin and having a gate hole formed at a predetermined position is set in a cavity mold. And
A core mold is opposed to the cavity mold to form a cavity space, and the cavity space is filled with a second resin through the gate hole to form a two-layer parison. Is opposed to a blow mold, and compressed air is blown to expand the two-layer parison.

In another two-layer injection blow molding method of the present invention, the gate hole is formed at the center of the insert parison. In still another two-layer injection blow molding method of the present invention, the core mold further includes a core having a pressing projection formed at a tip thereof, and when the core mold is opposed to the blow mold, The two-layer parison is held by the holding projection.

[0007] In still another two-layer injection blow molding method of the present invention, the first resin is colored more strongly than the second resin. In still another two-layer injection blow molding method of the present invention, a light shielding (shield) plate is further held by the pressing projections.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a use state of a light bulb glove according to an embodiment of the present invention. In the figure, reference numeral 12 denotes a globe for a light bulb, and 13 denotes a light bulb housed in the globe 12 for a light bulb. The bulb globe 12 has a neck portion 48 having a screw 47 formed on the outer periphery, a single-layer structure, and a transparent or lightly colored body portion 5.
It has a one- and two-layer structure and comprises a darkly colored front part 52. The front part 52 includes an outer layer 54 and an inner layer 55, and a light shielding part 53 is formed at the center of the front part 52. The body 51 and the inner layer 55 are formed of a second resin, and the outer layer 54 is formed of a first resin. The light shielding portion 53 is formed integrally with the light shielding plate 17 so that the light of the light bulb 13 does not pass through the center of the front portion 52.

Therefore, when the light bulb 13 is turned on, not only is the front part 52 darkly colored, but also the light shielding plate 17 prevents light from the light bulb 13 from passing through the center of the front part 52. So it does not irritate the eyes. Also, since the body 51 is transparent or lightly colored,
The illuminance of the light bulb 13 is not attenuated, the brightness of the entire room can be maintained, and the hand does not become dark.

Next, a blow molding apparatus for manufacturing the bulb globe 12 having the above-described configuration will be described. FIG. 2 is a view showing a core mold of the parison mold apparatus according to the embodiment of the present invention, FIG. 3 is a view showing a tip of a core in the embodiment of the present invention, and FIG. 4 is a view showing an embodiment of the present invention. FIG. 5 is a front view of the light shielding plate according to the embodiment of the present invention, FIG. 6 is a partial cross-sectional view of the light shielding plate according to the embodiment of the present invention, and FIG. FIG. 8 is a cross-sectional view of a parison for an insert according to an embodiment of the present invention. FIG. 8 is a view showing a state in which a parison for an insert is set in a cavity mold of a mold apparatus for a parison according to an embodiment of the present invention. FIG. 10 is a cross-sectional view of a parison die apparatus in FIG. 10, FIG. 10 is an enlarged view of a main part of the parison die apparatus in the embodiment of the present invention, FIG. FIG. 12 shows an embodiment of the present invention. Kick is a fragmentary cross-sectional view of the glove for a light bulb.

In FIG. 2, reference numeral 56 denotes a core mold. The core mold 56 is combined with a cavity mold 57 shown in FIG. 9 so as to face the cavity mold 57 to constitute a parison mold apparatus. A blow mold device is formed by being combined with the blow mold 58 shown in the figure so as to face the blow mold 58. Reference numeral 11 denotes a core having a hemispherical tip, and a pressing projection 61 is formed at the center of the tip of the core 11 so as to project toward the cavity mold 57. As shown in FIGS. 3 and 4, the presser projection 61 includes four arc-shaped portions 62 arranged in a circumferential direction, and is provided between the arc-shaped portions 62 and radially inward portions of the arc-shaped portions 62. A counterbore 63 is formed.

The light shield plate 17 shown in FIGS. 5 and 6 can be set in the counterbore 63. Therefore, the light shielding plate 17 is provided at the central cylindrical portion 6.
4, and a locking portion 65 formed so as to protrude radially outward from the cylindrical portion 64 in a “C” shape.
When the set 7 is set on the counterbore 63, each locking portion 65 is inserted between the arc-shaped portions 62.

Further, in the vicinity of the body 67 of the core 11,
An annular block 66 for forming the neck portion 48 of the bulb globe 12 (FIG. 1) is detachably provided, and an inner peripheral surface of the annular block 66 has a screw mold 6 corresponding to the screw 47.
8 are formed. Reference numeral 71 denotes a support block for attaching the core 11, and reference numeral 72 denotes a sleeve. An annular groove 69 is formed in the sleeve 72 in the vicinity of the peripheral edge of the end surface S1, and a blowing passage 20 is formed facing the groove 69. The blowing passage 20 is not shown via an on-off valve 84. Connected to compressed air source.

In FIG. 7, reference numeral 14 denotes a hemispherical insert parison in which a gate hole 15 is formed in the center and which is heavily colored. The insert parison 14 is formed in advance by a first resin using a parison mold (not shown), and becomes the outer layer 54 of the front portion 52 when the bulb globe 12 (FIG. 1) is completed. As shown in FIG. 8, the cavity mold 57 includes an outer block 73 having a cylindrical space and an inner block 74 having a hemispherical space.
A gate 75 is formed at the center of 4 so as to communicate with the gate hole 15 when the insert parison 14 is set in the cavity mold 57. The inner block 74 has an annular groove 78 near the periphery of the end surface S2.
However, the suction passages 16 are respectively formed facing the grooves 78, and the suction passages 16 are connected to a negative pressure source (not shown) via an on-off valve 77.

As shown in FIG. 11, the blow mold 58 is composed of body forming blocks 85a and 85b and a front part forming block 86, and the body forming blocks 85a and 85b and the front part forming block are formed. A cavity space 87 having a shape corresponding to the outer peripheral surface of the bulb globe 12 is formed by each inner peripheral surface of the lighting block 86. Next, a two-layer injection blow molding method for molding the bulb globe 12 will be described.

First, on the core mold 56 side, the light shielding plate 17 is set on the counterbore 63 of the holding projection 61, and on the cavity mold 57 side, the gate hole 15 is formed.
The insert parison 14 is set in the inner block 74 so that the gate and the gate 75 communicate with each other. Subsequently, the on-off valve 77 is opened, a negative pressure is generated in the suction passage 16 to suck the insert parison 14, and the inner block 74 is opened.
And close contact.

Subsequently, a mold clamping device (not shown) is operated,
As shown in FIG. 9, when the core mold 56 is moved forward (moved to the right in the figure) to close the mold, a cavity space 81 is formed between the core 11 and the outer block 73. At this time, each arc-shaped portion 62 of the presser projection 61 presses the vicinity of the gate hole 15 of the parison 14 for insert. Since the height of the arc-shaped portion 62 is made larger than the thickness of the light shielding plate 17, when the light shielding plate 17 is brought into close contact with the core 11, a part of the counterbore portion 63 between the arc-shaped portions 62 is formed. It becomes a resin channel.

Next, the mold is clamped by the mold clamping device, and the cavity space 81 is filled with a transparent or faintly colored and molten high-temperature second resin through the gate 75. At this time, the second resin that has passed through the gate 75 further enters the cavity space 81 through the gate hole 15. As a result, as shown in FIG.
Two-layer parison 8 including resin layer 92 and second resin layer 93
2 are molded. After completion of the bulb globe 12, the first resin layer 92 and the second resin layer 93 become the outer layer 54 and the inner layer 55, respectively. Then, the core mold 56 is retracted by the mold clamping device (moves to the left in the drawing).
The mold is opened. At this time, the core mold 56
At the same time, the two-layer parison 82 is retracted.

Subsequently, the core mold 56 is reversed by a reversing mechanism (not shown) to face the blow mold 58, and the mold is closed and clamped again by the mold clamping device as shown in FIG. Done. And the core mold 5
In a state where the core 11 is maintained at an appropriate temperature by a temperature controller (not shown) disposed at 6, the open / close valve 84 is opened, and compressed air is supplied between the core 11 and the two-layer parison 82 through the blowing passage 20. Inhale. As a result, the two-layer parison 82 is expanded in the cavity space 87 and has a shape along the inner peripheral surfaces of the body forming blocks 85a and 85b and the front part forming block 86.

Thereafter, when the two-layer parison 82 is cooled and the core mold 56 is retracted and the mold is opened, the bulb globe 12 is completed. Note that the body forming blocks 85a and 85b are moved in the directions of arrows A and B in FIG. by the way,
FIG. 12 shows a state in which the bulb globe 12 is completed.
As shown in the figure, the light shielding plate 17, the outer layer 54 and the inner layer 5
5 together constitute a front part 52. Then, the second resin remains in the gate hole 15 to form the protrusion 91 of the inner layer 55. In this case, since the protrusion 91 is formed of the second resin, light is easily transmitted. However, the light of the bulb 13 is projected by the light shielding plate 17.
Prevents light from permeating, so it does not irritate the eyes and is easy on the eyes.

In the present embodiment, the two-layer injection blow molding method is described as a method for molding the bulb globe 12, but it is used to reinforce the bottom of a container such as a carbonated beverage container (not shown). It can also be used as a method. In that case, the insert parison is used as a reinforcement to reinforce the bottom of the container. Also,
By making the color of the resin for the insert parison different from the color of the resin for injection molding, a two-color container can be molded. Can be molded.

As described above, in this embodiment, since the insert parison 14 is set in the cavity mold 57, the second resin passes through the gate 75 and flows along the core mold 56. It will enter the cavity space 81. Therefore, the dynamic pressure of the molten high-temperature second resin does not significantly affect the parison 14 for the insert, so that the parison 14 for the insert is melted and deformed, or the first resin is deformed by the second resin. Can be prevented from being washed away. As a result, the first resin and the second resin are mixed in the body portion 51 to be spotted (mottled), or the light is randomly refracted in the front portion 52 to make the irradiation light non-uniform. Nothing.

When the compressed air is blown between the core 11 and the two-layer parison 82, the two-layer parison 82 is held by the pressing projection 61 and pressed against the front-part molding block 86. I have. Therefore,
Since the tip of the two-layer parison 82 is pressed against the front-part molding block 86 during expansion, a molded product without uneven thickness can be obtained.

Further, the temperature adjusted by the temperature controller (not shown) of the cavity mold 57 is set lower than the temperature adjusted by the temperature controller of the core mold 56. Therefore, since the insert parison 14 is not excessively heated, it is possible to prevent the insert parison 14 from being deformed when the second resin enters the cavity space 81.

The core 1 in the two-layer parison 82
Since the entire surface facing 1 is covered with the second resin layer 93, the bonding force between the core 11 and the two-layer parison 82 becomes uniform. Therefore, when the compressed air is blown between the core 11 and the two-layer parison 82, the two-layer parison 82 can be expanded uniformly, so that the quality of the molded product can be improved.

The present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0027]

As described in detail above, according to the present invention, in the two-layer injection blow molding method, the insert parison molded with the first resin and having a gate hole formed at a predetermined position is provided with a cavity. The mold is set, a core mold is opposed to the cavity mold to form a cavity space, and the cavity space is filled with a second resin through the gate hole to form a two-layer parison. The core mold is opposed to the blow mold, and compressed air is blown to expand the two-layer parison.

In this case, if the first resin is colored deeper than the second resin to form the bulb globe, the front part of the bulb globe is colored deeper, which is easy on the eyes. Since the illuminance of the light bulb is not attenuated in the body of the light bulb glove, the overall brightness of the room can be maintained, and the hand does not become dark. Also, when molding the container, the parison for the insert can be used as a reinforcing material for reinforcing the bottom of the container.

Since the insert parison is set in the cavity mold, the dynamic pressure of the molten high-temperature second resin does not significantly affect the insert parison. Therefore, it is possible to prevent the insert parison from being melted and deformed, and from flowing the first resin by the second resin. As a result, the first resin and the second resin are mixed in the torso of the bulb globe to be spotted,
Irradiation light does not become uneven due to random refraction of light at the front of the bulb globe.

Further, the temperature adjusted by the temperature controller of the cavity mold is set lower than the temperature adjusted by the temperature controller of the core mold. Therefore, since the insert parison is not excessively heated, it is possible to prevent the insert parison from being deformed when the second resin enters the cavity space. Then, the entire surface of the two-layer parison facing the core is covered with the second resin, so that the bonding force between the core and the two-layer parison becomes uniform. Therefore, when the compressed air is blown between the core and the two-layer parison, the two-layer parison can be evenly expanded, so that the quality of the molded product can be improved.

[0031] In another two-layer injection blow molding method of the present invention, the core mold further includes a core having a pressing projection formed at a tip thereof, and the core mold is opposed to the blow mold. Then, the two-layer parison is held by the holding projection. In this case, when the compressed air is blown between the core and the two-layer parison, the two-layer parison is held by the pressing projection and pressed against the blow mold. Therefore, it is possible to obtain a molded product without uneven thickness.

[0032] In still another two-layer injection blow molding method of the present invention, the first resin is colored deeper than the second resin. In this case, when the light bulb glove is molded, the front part of the light bulb glove is deeply colored, so that the eyes are not irritated. Also,
Since the illuminance of the light bulb is not attenuated at the trunk of the light bulb glove, the overall brightness of the room can be maintained and the hand does not become dark.

In still another two-layer injection blow molding method of the present invention, the light shielding plate is further held by the pressing projection. In this case, the light shielding plate prevents light from the light bulb from passing through the center of the front part of the light bulb glove, so that it is easy on the eyes.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a use state of a light bulb globe according to an embodiment of the present invention.

FIG. 2 is a view showing a core mold of the parison mold apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing a tip of a core according to the embodiment of the present invention.

FIG. 4 is a front view of a tip of a core according to the embodiment of the present invention.

FIG. 5 is a front view of the light shielding plate according to the embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of the light shielding plate according to the embodiment of the present invention.

FIG. 7 is a sectional view of an insert parison according to an embodiment of the present invention.

FIG. 8 is a view showing a state in which a parison for an insert is set in a cavity mold of the mold apparatus for a parison according to the embodiment of the present invention.

FIG. 9 is a sectional view of a parison mold device according to an embodiment of the present invention.

FIG. 10 is an enlarged view of a main part of the parison mold device according to the embodiment of the present invention.

FIG. 11 is a cross-sectional view of the blow mold apparatus according to the embodiment of the present invention.

FIG. 12 is a cross-sectional view of a main part of the bulb globe according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Core 14 Parison for insert 15 Gate hole 17 Light shielding plate 56 Core mold 57 Cavity mold 58 Blow mold 61 Pressing projection 81 Cavity space 82 Double layer parison

Claims (5)

[Claims] 1. A parison for insert molded with a first resin and having a gate hole formed at a predetermined position is set in a cavity mold, and (b) a core mold is opposed to the cavity mold. To form a cavity space,
(C) filling the cavity space with a second resin through the gate hole to form a two-layer parison; and (d) facing the core mold with a blow mold and blowing compressed air into the cavity. A two-layer injection blow molding method characterized by expanding a layer parison. 2. The two-layer injection blow molding method according to claim 1, wherein the gate hole is formed at the center of the insert parison. 3. The core mold includes a core having a holding projection formed at a tip thereof. (B) When the core mold is opposed to a blow mold, two layers are formed by the holding projection. The method of claim 1 wherein the parison is retained. 4. The two-layer injection blow molding method according to claim 1, wherein the first resin is colored deeper than the second resin. 5. The two-layer injection blow molding method according to claim 3, wherein the light shielding plate is held by the holding projection.