JPH0939030A - Hollow molded product and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a hollow molded product suitable for a cover or a protector equipped with an attaching part high in dimensional accuracy for the attachment at a predetermined position and a cushion part relaxing an impact. SOLUTION: A hollow molded product 11 is equipped with a hard first constitutional member 12, a soft constitutional member 13 and a connecting member 14. The first constitutional member 12 is formed by filling a first polymeric material into a first cavity in a liquid state to cure the same and the second constitutional member 13 is formed by filling a second polymeric material into a second cavity in a liquid state to cure the same. A hollow part 10 is formed between the second constitutional member 13 and the first constitutional member 12 when both member 13, 12 are brough to a contact state. The connection member 14 is formed along the contact part of the first and second constitutional members 12, 13 and bonded to the respective constitutional members 12, 13 to connect both members 12, 13 in an inseparable state.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a molded product having a hollow portion and a manufacturing method suitable for manufacturing the hollow molded product.

[0002]

2. Description of the Related Art Conventionally, as a method suitable for producing a hollow molded article having a hollow portion and having a uniform wall thickness, for example, JP-A-5-97008 and JP-A-6-320572.
There is a die slide molding method (die slide injection method, which is abbreviated as DSI method) disclosed in Japanese Patent Laid-Open Publication No.

In this method, a pair of cavities are formed between the movable mold and the slide mold by clamping them. Molten resin is simultaneously injected into each cavity from one nozzle of the injection molding machine and cured. Then, the first constituent member and the second constituent member are respectively molded. When the movable die and the slide die are opened, the first component remains in the movable die and the second component remains in the slide die. By sliding the slide mold, both constituent members are opposed to each other and the mold is clamped. Then, between the movable die and the slide die, both constituent members are brought into contact with each other, and
An annular cavity is formed around the abutting portion.
When the molten resin is injected into the annular cavity from the nozzle and cured, an annular connecting member that connects the two constituent members is formed around the abutting portion of the two constituent members. In this way, a hollow molded product including the first constituent member, the second constituent member, and the connecting member is manufactured.

[0004]

By the way, some hollow molded products include covers and protectors. These require a mounting portion for mounting the hollow molded product at a predetermined position on another member and a cushioning portion for cushioning an externally applied impact. The former requires high rigidity and the latter requires flexibility.

However, in the above-mentioned manufacturing method, since the molten resin injected from one nozzle of the injection molding machine is simultaneously supplied to both cavities, the respective constituent members are formed of the same kind of polymeric material. It will be.
Therefore, what can be manufactured by this manufacturing method is limited to the hollow molded product in which both constituent members have the same hardness, and there is a problem that it is not possible to deal with the hollow molded product which requires the contradictory characteristics regarding hardness as described above. there were.

The present invention has been made in view of the above-mentioned circumstances, and its object is suitable for a cover, protector, etc. having a mounting portion for mounting at a predetermined position and a buffer portion for cushioning an impact. Another object is to provide a hollow molded article and a manufacturing method thereof.

[0007]

In order to achieve the above object, the first invention according to claim 1 is to fill and cure the first polymer material in a liquid state in the first cavity. When formed by filling and hardening the formed hard first constituent member and the second polymer material in a liquid state in the second cavity, when brought into contact with the first constituent member And a soft second constituent member that forms a hollow portion between the constituent member and the same constituent member, and is made of a polymer material, and is formed along the abutting portions of the first constituent member and the second constituent member. , And a connecting member that connects the two constituent members by joining them.

In the first aspect of the present invention, one side portion of the hollow molded article is occupied by the hard first constituent member and the other side portion is occupied by the soft second constituent member. Therefore, it is possible to use the one side portion as a mounting portion and the other side portion as a cushioning portion. In this case, the hollow molded article is attached to the other member at a predetermined position by the first component member. When an impact is applied to the hollow molded article from the outside, the impact is softened by the second component. The connecting member holds the both constituent members in contact with each other by joining the first constituent member and the second constituent member, respectively.

Each of the first constituent member, the second constituent member and the connecting member constituting the hollow molded article is formed by filling and hardening a polymer material in a predetermined cavity. Therefore, each member has a small variation in shape and thickness and is highly accurate.

According to a second aspect of the present invention, a hard first component is molded by filling and hardening a first polymer material in a liquid state in a first cavity of a molding device. A step of molding a soft second constituent member by filling and hardening a second polymer material in a liquid state into the second cavity of the molding apparatus; the first constituent member and the first constituent member; A step of bringing the two constituent members into contact with each other so that a hollow portion is formed between them; and a liquid state polymer material in a third cavity formed around the contact portions of the two constituent members. And a step of molding the connecting member in a state of being joined to both the constituent members by filling and curing.

According to the second aspect of the invention, the first polymer material in a liquid state is filled in the first cavity of the molding apparatus. When the first polymer material is cured, a hard first component having a shape corresponding to the first cavity is molded. Further, the second polymer material in a liquid state is filled in the second cavity of the molding apparatus. When the second polymer material is hardened, a soft second component having a shape corresponding to the second cavity is molded. The first component and the second component are then abutted against each other such that a hollow space is created between them. Then, the liquid state polymer material is filled in the third cavity formed around the abutting portions of both the constituent members. When the polymer material is hardened, a connecting member that is in a state of being joined to both the constituent members is formed around the abutting portions of the both constituent members.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment embodying the first and second inventions will be described below with reference to the drawings. As shown in FIG. 1, the hollow molded product 11 such as the cover and the protector is the first
A hard first constituent member 12 made of a polymeric material, and a second soft constituent member 13 made of a second polymeric material,
A band-shaped connecting member 14 which is made of a polymer material and which connects both the constituent members 12 and 13 is provided. Here, polypropylene (PP) is used as the first polymer material,
Polypropylene (PP) mixed with rubber is used as the second polymer material. The polymer material forming the connecting member 14 is the same as the first polymer material.

First component 12 and second component 1
All 3 have a U-shaped cross section, and the side edge 12a of one constituent member 12 is brought into contact with the side edge 13a of the other constituent member 13 facing each other, and a hollow space is formed between both constituent members 12 and 13. The part 10 is formed. Notches 12b and 13b are formed on the outer side portions of the side edge portions 12a and 13a of the constituent members 12 and 13, respectively.
Are formed. In a state in which the two constituent members 12 and 13 are in contact with each other, a groove 15 formed of the notches 12b and 13b is formed between the side edge portions 12a and 13a.

A connecting member 14 is filled in the groove 15. The connecting member 14 is made of a polymer material that is compatible with the polymer materials that form the first and second constituent members.
Here, the connecting member 14 is made of the same material (rubber mixed PP) as the second component 13. The connecting member 14 is joined to both the first component member 12 and the second component member 13, and holds both the component members 12 and 13 in a state of abutting each other. In this state, the first component 12 and the connecting member 1
4, there is substantially no gap, and there is substantially no gap between the second component member 13 and the connecting member 14. The outer surface of the connecting member 14 and the outer surfaces of the side edge portions 12a and 13a are located on the same plane (so-called flush).

Next, the molding device 16 used for manufacturing the hollow molded article 11 will be described. As shown in FIGS. 2 and 3, the molding apparatus 16 includes a base 17, on which a fixed platen 18 is immovably locked. Fixed platen 18
A first nozzle 19 of an injection machine is attached to the nozzle, from which a first polymer material 20 is injected. A second nozzle 21 of an injector is mounted above the first nozzle 19 on the stationary platen 18, and a second polymer material 22 is injected from this nozzle.

A fixed die 23 is attached to the front surface (right side surface in the drawing) of the stationary platen 18. On the fixed mold 23 is a stand 24
Is installed upright, and a cylinder for sliding 25
Is attached (see FIG. 5). The cylinder 25 operates (moves up and down) the piston rod 26 by hydraulic pressure, air pressure and the like. A slide die 27 is connected to the lower end of the piston rod 26. The slide type 27
In a state in which the piston rod 26 is in the state of being in contact with the fixed die 23, the piston rod 26 is most protruded from the cylinder 25 (FIGS. 2 to 4),
The piston rod 26 is slid up and down between the piston rod 26 and the uppermost position (FIGS. 5 to 7) that is most retracted in the cylinder 25.

A movable platen 28 is placed on the base 17, and a movable die 29 is provided on the rear surface (left side surface in the figure) of the movable platen 28.
Is installed. The movable platen 28 is moved in the horizontal direction by a mold opening / closing device (not shown), and approaches and separates from the fixed platen 18. The movable mold 29 has a mold matching position (FIGS. 2, 3 and 6) in close contact with the slide mold 27 and the slide mold 2
It is movable between the mold open position (FIGS. 4, 5, and 7) separated from 7.

When the slide die 27 is held in the lower position and the movable die 29 is held in the die matching position, both dies 2 are held.
7, 29 abut each other. In this state, a first cavity 30 for molding the first constituent member 12 and a second cavity 31 for molding the second constituent member 13 are formed between the slide mold 27 and the movable mold 29. They are formed at positions vertically separated from each other. The first cavity 30 includes a molding recess 32 formed in the slide mold 27 and a movable mold 29.
The second cavity 31 includes a molding recess 34 formed in the movable mold 29 and a molding protrusion 35 formed in the slide mold 27. Further, the slide die 27 is held at the upper position, and the movable die 29
Both molds when they are held in the mold alignment position (Fig. 6).
7, 29 abut each other. In this state, a third cavity 36 for molding the connecting member 14 is formed between the slide die 27 and the movable die 29.

In the fixed mold 23, each nozzle 19, 21
First and second sprues 37 and 38 penetrating the fixed mold 23 are opened at a position corresponding to. The slide die 27 allows the first sprue 37 and the first cavity 30 to communicate with each other when it is in the lower position, and the second sprue 38 when it is in the upper position (FIG. 6).
A first sub-sprue 39, a runner, a gate, etc. for connecting the third sub-cavity 36 with the third sub-cavity 36 are formed.
The slide die 27 is provided with a second sub-sprue 40, a runner, a gate, etc. for communicating the second sprue 38 and the second cavity 31 when it is in the lower position.

In order to manufacture the hollow molded product 11 using the molding device 16 as described above, first, as shown in FIG. 2, the piston rod 26 is largely projected downward from the cylinder 25, and the slide die 27 is moved downward. Move to position. The movable platen 28 is moved so as to approach the fixed platen 18, and the movable mold 29 is matched with the slide mold 27. In this state, the first
Sub-sprue 39 is continuous with the first sprue 37, and the second sub-sprue 40 is continuous with the second sprue 38. A pair of cavities 30 and 31 are formed between the slide die 27 and the movable die 29.

As shown in FIG. 3, the molten first polymer material 20 is injected from the first nozzle 19 of the injector.
The polymer material 20 is introduced into the first cavity 30 through the first sprue 37, the first sub-sprue 39, the runner, and the gate in this order. Almost at the same time, the molten second polymer material 22 is injected from the second nozzle 21.
The polymer material 22 is introduced into the second cavity 31 through the second sprue 38, the second sub-sprue 40, the runner, and the gate in this order. The two kinds of polymer materials 20 and 22 thus introduced are filled in the cavities 30 and 31, respectively, and are cooled and hardened. Then, the first component member 1 having the notch 12b in the first cavity 30 is formed.
2 is molded, and the notch 13b is formed in the second cavity 31.
The second component 13 having is formed.

Subsequently, as shown in FIG. 4, the movable die 29 is separated from the slide die 27 by the die opening / closing device. Then, the molding protrusions 33 and 35 are separated from the constituent members 12 and 13, and the constituent members 12 and 13 remain on the molding concave portions 32 and 34 side. That is, the first component 12 is the slide die 2
7, the second component member 13 remains attached to the movable mold 2.
It remains attached to 9.

At the time of opening the mold, the first sprue 37,
Excess resin 41 solidified by the first sub-sprue 39, runner, etc. is projected from the fixed mold 23 and the slide mold 27,
The part corresponding to the gate is separated from the first component member 12 and falls. Similarly, the surplus resin 4 solidified by the second sprue 38, the second sub-sprue 40, the runner, etc.
2 is projected from the fixed mold 23 and the slide mold 27, separated from the second component member 13 at the portion corresponding to the gate, and falls.

Next, as shown in FIG. 5, the piston rod 26 is retracted into the cylinder 25, and the slide die 27 is moved to the upper position. Then, the second component member 13 remaining attached to the molding recess 34 of the movable die 29 and the first component member 12 remaining attached to the molding recess 32 of the slide die 27 face each other. At this time, the first sub-sprue 39 is continuous with the second sprue 38.

In this state, the movable die 29 is moved to the slide die 27 side, and the two pieces 29, 27 are brought together as shown in FIG. 6, so that the side edge portions 12a, 13a of the respective constituent members 12, 13 are brought into contact with each other. To be And the side edge portions 12a, 1 thereof
A third cavity 36 is formed between 3a, the movable die 29, and the slide die 27. This cavity 36
It communicates with the first sub-sprue 39 via a gate and a runner.

When the molten second polymer material 22 is injected from the second nozzle 21 of the injection machine, the polymer material 2
2 passes through the second sprue 38, the first sub-sprue 39, the runner and the gate in this order and is filled in the third cavity 36. When the second polymer material 22 is hardened, the strip-shaped connecting member 1 in a state of being bonded to both the first component member 12 and the second component member 13 around the contact portion.
4 is molded. The hollow molded product 11 in which the first and second constituent members 12 and 13 are connected by the connecting member 14 is obtained.

As shown in FIG. 7, the slide mold 27 and the movable mold 29 are opened again by the mold opening / closing device, and the hollow molded product 11 is taken out from the molding device 16. At this time, the second sprue 38, the first sub-sprue 39, the surplus resin 43 solidified in the runner, etc. are separated from the hollow molded product 11 at the portion corresponding to the gate. From this state, the piston rod 26 is again projected from the cylinder 25, the slide die 27 is slid to the lower position, and the movable die 29 is aligned with the slide die 27. Then, it returns to the state of FIG. 2 again, and can be prepared for the next production of the hollow molded article 11.

The hollow molded article 11 is continuously molded by repeating such a series of steps. Moreover, the molded product 11 is molded by the simple steps of sliding the slide mold 27, aligning and opening the mold by moving the movable mold 29, and injecting the polymer materials 20 and 22 in a molten state. Therefore, the entire process can be easily automated and mass production becomes possible.

Further, in manufacturing the hollow molded article 11,
The molding of the first constituent member 12 and the molding of the second constituent member 13 are performed substantially at the same time. Therefore, the time required for a series of steps can be shortened and the production efficiency can be improved.

In the hollow molded article 11 thus obtained, as shown in FIG. 1, one side portion (the left side portion in the figure) is occupied by the hard first component member 12 and the other side portion (the left side portion in the figure). The right side of the) is occupied by the soft second component 13. Therefore, it is possible to use the one side portion as a mounting portion and the other side portion as a cushioning portion. In this case, the hollow molded product 11 is attached to a predetermined position of another member by the first component member 12. When an impact is applied to the hollow molded product 11 from the outside, the impact is softened by the second component member 13.

The first constituent member 12, the second constituent member 13 and the connecting member 14 constituting the hollow molded article 11 are all provided with the polymeric materials 20, 22 in the cavities 30, 31, 36 of a predetermined shape. It is molded by filling and curing. Therefore, each of the members 12, 13 and 14 is highly accurate with little variation in shape and thickness. This is important in the hollow molded article 11, especially for the first component member 12, and the attachment accuracy when attaching the member 12 to another member is improved. Further, since the hollow molded product 11 has a structure in which the two constituent members 12 and 13 are connected by the connecting member 14 as described above, the outer surface of the molded product 11 has a space between the first structural member 12 and the connecting member 14, and Component 1 of 2
A boundary portion appears between 3 and the connecting member 14. However, as described above, the connecting member 14 is formed by filling the third cavity 36 with the second polymer material 22. Therefore, there is substantially no gap between the first component member 12 and the connecting member 14 or between the second component member 13 and the connecting member 14, and there is no step at the boundary portion, and the surface is flat. A hollow molded product 11 having a high surface quality can be obtained.
Therefore, the hollow molded article 11 is suitable for a cover, protector, etc. having a mounting portion for mounting at a predetermined position and a buffer portion for cushioning impact.

Here, as a method of connecting both the constituent members 12 and 13, it is possible to directly bond the both members 12 and 13 to each other by a means such as an adhesive or vibration welding without using the connecting member 14. To be However, in this case, the adhesive or the welded portion protrudes from between the constituent members 12 and 13,
There is a risk of degrading the surface quality. On the other hand, in this embodiment, as described above, since the three members 12 to 14 are connected by utilizing the compatibility between the respective constituent members 12 and 13 and the connecting member 14, the protrusion of the adhesive or the like can be prevented. A hollow molded product 11 having a clean outer surface can be obtained.

Further, the connecting member 14 is the first component member 1.
The second component member 13 and the second component member 13 are joined together, and at this joint portion, both members 12, 14 or 13, 14 are mixed and integrated. That is, the connecting member 1
4 is in a state of being firmly adhered to both of the constituent members 12 and 13, and keeps the both 12 and 13 in contact with each other. Therefore, even if an external impact is applied to the soft second constituent member 13, it is possible to reliably prevent the constituent members 12 and 13 from being separated from each other.

The present invention can be embodied in another embodiment shown below. (1) Instead of a combination of PP and rubber-containing PP, hard TPR (thermoplastic polyester elastomer) is used as the first polymer material, and soft TPR is used as the second polymer material.
PR may be used. In addition, a hard TIP (composite reinforced polypropylene) may be used as the first polymer material and a soft TIP may be used as the second polymer material.

(2) In the above embodiment, the connecting member 14
Is made of the same material as the second constituent member 13 (rubber mixed PP), but it may be made of the same material (PP) as the first constituent member 12 instead.

Although the respective embodiments of the present invention have been described above, technical ideas other than the claims which can be understood from the respective embodiments will be described below together with their effects. (A) In the manufacturing method according to claim 2, a method for manufacturing a hollow molded product, wherein the step of molding the first constituent member and the step of molding the second constituent member are performed substantially at the same time. By doing so, the time required for a series of steps for producing a hollow molded article can be shortened and the production efficiency can be improved.

(B) In the molded article according to claim 1,
The hollow molded article, wherein the connecting member is formed of a material having compatibility with the first constituent member and the second constituent member. With this configuration, both constituent members can be firmly connected by the connecting member.

[0038]

As described above in detail, according to the first and second aspects of the invention, a cover provided with a mounting portion with high dimensional accuracy for mounting at a predetermined position and a cushioning portion for cushioning impact, It is possible to provide a hollow molded article suitable for a protector and the like, and a manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hollow molded product.

FIG. 2 is a partial cross-sectional view showing a state before a polymer material is injected into a mold-clamped molding device.

3 is a partial cross-sectional view showing a state where a polymer material is filled in a cavity of the molding apparatus of FIG.

FIG. 4 is a partial cross-sectional view showing a state where the molding apparatus of FIG. 3 is opened.

5 is a partial cross-sectional view showing a state where the slide die of the molding apparatus of FIG. 4 is slid upward.

6 is a partial cross-sectional view showing a state where the molding apparatus of FIG. 5 is clamped again and the third cavity is filled with a polymer material.

FIG. 7 is a partial cross-sectional view showing a state where the molding apparatus of FIG. 6 is opened again.

[Explanation of symbols]

10 ... Hollow part, 12 ... 1st component member, 13 ... 2nd component member, 14 ... Connection member, 16 ... Molding apparatus, 20 ... 1st
Polymeric material, 22 ... second polymeric material, 30 ... first cavity, 31 ... second cavity, 36 ... third cavity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Katagiri No. 1 Nagahata, Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Toyoda Gosei Co., Ltd.

Claims (2)

[Claims] 1. A rigid first component (12) formed by filling and curing a first polymeric material (20) in a liquid state in a first cavity (30); Is formed by filling and curing the second polymer material (22) in the liquid state in the cavity (31) of the same, and when the second polymer material (22) is brought into contact with the first component (12), the same component is formed. A soft second constituent member (13) forming a hollow portion (10) between the first constituent member (12) and the second constituent member (13). ) Is formed along the contact portion,
A hollow molded article provided with a connecting member (14) for connecting both constituent members (12, 13) by joining each constituent member (12, 13). 2. A rigid first component (1) by filling and curing a first polymeric material (20) in a liquid state in a first cavity (30) of a molding device (16).
2) molding, and a soft second component by filling and hardening the second polymer material (22) in a liquid state in the second cavity (31) of the molding device (16). A step of molding (13), the first component (12) and the second component (1)
3) abutting each other so that a hollow portion (10) is formed between them, and a third cavity (36) formed around the abutting portions of both the constituent members (12, 13). A connecting member (14) in a state of being joined to both constituent members (12, 13) by filling and hardening a polymer material (22) in a liquid state therein.
And a step of molding the hollow molded article.