JP2932454B2 - Composite molded article and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite molded article applicable to a synthetic resin molded article for a vehicle such as a headrest, a sun visor, an armrest and the like, and a method for producing the same.

[0002]

2. Description of the Related Art A synthetic resin molded article for a vehicle, such as a headrest, a sun visor, an armrest, etc., is a composite molded article in which the surface of a core layer made of a foamed molded article is covered with a non-foamed resin exterior material layer. A stay is inserted into the composite molded body to reinforce the composite molded body and to attach the composite molded body to a predetermined portion of the vehicle.

Conventionally, as a method of manufacturing such a composite molded body, a non-foamed resin is blow-molded in a state where a stay is inserted into a molding die to form an exterior material layer. A method of forming a core layer made of a foamed molded article by injecting a foamed resin such as urethane from a hole formed at the time of blow molding after integrating an exterior material layer;
As disclosed in No. 3, while a stay is inserted into a molding die, a foamed resin such as urethane is injected to form a core material layer made of a foamed molded body. A method is known in which the core material layer is coated with an exterior material layer made of a non-foamed resin.

[0004]

Among the prior arts, in the former method, since the adhesive strength between the stay and the core material layer is weak, the surface of the stay is formed before the outer material layer is formed by blow molding. It was necessary to apply an adhesive in advance, and the molding operation was troublesome. In addition, when foaming resin such as urethane is injected into a preformed exterior material layer and foamed, the exterior material layer may be deformed by foaming pressure, and another mold for suppressing foaming pressure is required. There was a problem of becoming.

On the other hand, in the latter method, since the adhesive force between the stay, the core material layer and the exterior material layer is weak, the interface between the stay, the core material layer and the exterior material layer is peeled off in a relatively short time. In addition, there is a problem that a gap is formed in the composite molded body and the synthetic resin molded article for a vehicle vibrates during traveling.

The present invention has been made to solve such a conventional problem, and its object is to provide:
An object of the present invention is to provide a composite molded article in which the adhesion between the stay, the core material layer and the exterior material layer is enhanced, and a method for easily and efficiently producing the composite molded article.

[0007]

Means for Solving the Problems To achieve the above object, a composite molded article of the present invention is a composite molded article in which a core layer made of a foam molded article is formed in an exterior material layer made of a hollow molded article. By drilling multiple holes in the longitudinal and circumferential directions
The utility pipe used at the time of forming the composite molded body is left integrated in the composite molded body.

That is, after the composite molded article is manufactured, the utility pipe has a role as a stay.

Further, the method of manufacturing a composite molded article according to the present invention is characterized in that, when a hollow molded article is formed by blow molding, the plurality of holes are drilled in a lengthwise direction and a circumferential direction. More air is blown into the parison, and at the time of forming the foamed molded body, steam is blown into the hollow molded body from those holes of the utility pipe, and after forming the composite molded body, at least one of the utility pipes is formed. Is left in the composite molded body.

Further, in order to impart flexibility to the exterior material layer, it is preferable to use a thermoplastic elastomer resin as a material of the hollow molded body.

[0011]

By forming the foamed molded body before cooling and solidifying the hollow molded body, the boundary between the two is sufficiently welded, so that the core material layer and the exterior material layer are firmly bonded. On the other hand, at the time of foam molding, the foamed resin particles bite into the holes of the utility pipe due to the foaming pressure of the foamed resin particles, so that the utility pipe serving as a stay and the core material layer are firmly bonded.

Since the molding die used for blow molding is used as it is for foam molding, and the foaming pressure is suppressed by this molding die, it is not necessary to use another molding die. The molding process can also be simplified.

By using a thermoplastic elastomer resin as the material of the hollow molded body, flexibility can be imparted to the exterior material layer, so that the synthetic resin molded article for a vehicle can be made more comfortable to use.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the present invention is applied to the manufacture of a headrest of an automobile will be described with reference to the drawings.

FIG. 1A is an external perspective view showing an example in which the composite molded article of the present invention is applied to a headrest. In this headrest 1, no trace of an insertion hole of a blow-in pipe remains, and the headrest 1 contains foamed resin particles. Only the insertion hole trace of the filling feeder remains.

FIG. 2 is an external perspective view showing an embodiment of the utility pipe 2 integrated with the composite molded article. The utility pipe 2 has a width of 0.5 to 2.0 mm and a length of 5 mm. ~ 100mm
Several slit holes 3 are formed in the circumferential direction at predetermined intervals in the longitudinal direction at several locations. As a material of the utility pipe 2,
In general, iron is used. However, if the same material as the thermoplastic resin that is the material of the core material layer or the exterior material layer is used, recycling can be facilitated.

In this embodiment, the slit hole 3 is formed, but a round hole or any other shape may be formed without departing from the spirit of the present invention.

FIG. 1B is a longitudinal sectional view of the headrest. The expanded resin particles are completely fused to form a core material layer 4 which is a foam molded body. Due to the foaming pressure at this time, the expanded resin particles bite into the slit holes 3 of the utility pipe 2 by about 1 to 3 mm, so that the utility pipe 2 and the core material layer 4 are firmly bonded. Further, in order to form the foamed molded body 4 while remaining heat during blow molding remains, the exterior material layer 5 which is a hollow molded body is firmly bonded to the core material layer 4 which is a foamed molded body by heat welding. Is done.

As the thermoplastic resin used as the material of the exterior material layer 5 and the core material layer 4, polyethylene, polypropylene, polystyrene, polyethylene / styrene copolymer resin, thermoplastic elastomer and the like can be used.

Next, a description will be given of a manufacturing apparatus used when manufacturing the composite molded article of the present invention. 3 to 5
1 is a schematic cross-sectional view of a manufacturing apparatus for a composite molded article according to the present invention.

A parison extruder 7 is provided above the molding die 6.
The non-foamed resin is heated and melted in the parison extruder 7 and supplied to the molding die 6 as a parison a.

The utility pipe 2 and the filling feeder 8 are arranged below the molding die 6, and the lower end thereof is mounted on a mount 9 which can be moved up and down. Is fixed. The mounting base 9 can be moved up and down by attaching an elevating device 11 to its legs 10 and the like, and the utility pipe 2 and the filling feeder 8 can be moved into and out of the molding die 6. As the elevating device 11, a rack and pinion drive mechanism, a
A motor drive mechanism, a pneumatic or hydraulic cylinder drive mechanism, or the like can be employed.

Also, when the mounting base 9 is raised, the utility pipe 2 enters the molding die 6 to a certain depth so that air or the like can be uniformly blown into the entire molding die 6. In such a state, the filling feeder 8 is close to the inner wall surface of the molding die 6 or slightly protruded so that the utility pipe 2
And the length of the filling feeder 8 is different.

FIG. 3 shows an example in which the upper end of the utility pipe 2 is bent and continuous to be integrated into one, but two independent utility pipes may be used. When a large product is formed, a plurality of independent utility pipes may be used. As the utility pipe 2, a pipe having an open end with a pipe diameter smaller than the diameter of the foamed resin particles, a pipe having a plurality of slit holes 3 smaller than the diameter of the foamed resin particles formed on the peripheral surface, or the like is used. .

The utility pipe 2 blows air into the parison a at the time of blow molding, sucks air inside the hollow molded body before or during filling with foamed resin particles at the time of foaming molding, and removes foamed resin particles. It also serves to supply the steam to be heated, exhaust during the supply of the steam, and vacuum suction of the air at the time of cooling.

In the present embodiment, the air supply source 12 is supplied through a pressure reducing valve 13, an air pipe 14, and a valve 15,
The steam supply source 16 is connected to the lower end of the utility pipe 2 via a valve 17 and the vacuum device 18 is connected via a valve 19. A drain pipe 21 having a valve 20 is also connected to the lower end of the utility pipe 2. However, as these piping configurations, various configurations can be adopted according to the use, shape, and the like of the molded product.

The filling feeder 8 has a resin particle introduction port 22 and a resin particle hopper through a flexible pipe 23.
24 are connected, and the resin particle hopper 24 has
Pressurizing device 2 for effectively filling expanded resin particles b
The air supply source 12 is connected to an air injector port 26 of the air supply unit 5. Further, a piston valve 27 for opening and closing the resin particle introduction port 22 and the air injector port 26 is slidably fitted in the filling feeder 8.

A method for manufacturing the composite molded article of the present invention using the above-described manufacturing apparatus will be described with reference to FIGS.

First, as shown in FIG. 3, after the lower end of the utility pipe 2 is fixed to the utility pipe setting hole 28 of the mounting base 9, the parison extruder 7 arranged above the molding die 6 starts. Heat-fused parison a (for example, 180 to 220 ° C. for a polypropylene-based resin, 1
(60 to 200 ° C.) is extruded and supplied into the opened molding die 6. At this time, the molding die 6 is kept at 40 to 80 ° C.

After or before the parison a is supplied to the molding die 6, the mounting base 9 is raised, and the filling feeder 8 and the utility pipe 2 are inserted into the parison a. When the supply of the parison a ends, the molding die 6 is closed, and the parison a is closed.
Seal.

Then, the valves 15 and 15 of the air pipes 14 and 14 are opened, and the pressure reducing valve 13 is
Pressure of ^{2 to} 7 kg / cm ² (gage pressure)
Is blown into the parison a from the utility pipe 2 for 10 to 20 seconds to blow-mold the parison a to form the hollow molded body 5.

Next, as shown in FIG. 4, the valves 15, 15 of the air pipes 14, 14 are closed, and the hollow molded body 5 is closed.
In the course of cooling, the piston type valve 27 is opened, air is supplied from the air supply source 12 to the air-injector port 26, and the foamed resin particles b are pressure-fed by air to be hollowed through the resin particle introduction port 22. The molded body 5 is filled.

Before and during filling of the hollow resin body 5 with the foamed resin particles b, the valves 19, 19 communicating with the vacuum devices 18, 18 are opened, and the utility pipe 2 is used to open the valves 19, 19 from the utility pipe 2. Aspirate air. The suction pressure at this time is 300 ~
Preferably, the pressure is 760 mmHg.

In order to improve the filling efficiency of the foamed resin particles b, a pressing device 2 attached to the resin particle hopper 24 is used.
5, the pressure may be increased to a pressure of 0.5 to 3 kg / cm ² (gage pressure), preferably 1.0 to 1.2 kg / cm ² , and the hollow molded body 5 may be filled. The hollow molded body 5 may be filled with the foamed resin particles b by suction.

When the inside of the hollow molded article 5 is sucked, the hollow molded article 5 is easily depressed inward depending on the degree of cooling, size, shape, etc. of the hollow molded article 5. It is preferable that the hollow molded body 5 is attracted to the inner wall surface of the molding die 6 by vacuum suction from an exhaust hole communicating with the inner wall surface of the molding die 6 formed.

In the above-mentioned molding method, a so-called compression filling method in which the foamed resin particles b are filled in a compressed state into the hollow molded body 5 which has been pre-pressed in order to enhance the fusion efficiency between the foamed resin particles b. This method may be employed, and this method is particularly effective when the foamed resin particles b are of a polyolefin type.

As a compression filling method, for example, a valve 20 connected to a drain pipe 21 is opened and closed while supplying air into the hollow molded body 5 from an air pipe 14.
After the pressure is adjusted so that the inside of the hollow molded body 5 is kept at a constant pressurized state, the pressurizing device 2 attached to the resin particle hopper 24
5 is set to a pressure slightly higher than the pressure in the hollow molded body 5, for example, 0.1 to 3 kg / cm ² (gage pressure). There is a method of filling with a difference.

Next, each valve is closed, and each valve 17, 17 of the steam supply sources 16, 16 is opened, so that 0.1 to 1.2 kg / cm ² (gage) is filled between the filled foamed resin particles b. Pressure), preferably 0.8 to 1.0 kg / cm ² , 115
A steam at about 120 ° C. is blown from the utility pipe 2 for 2 to 20 seconds. As a result, the foamed resin particles b that have been pre-foamed are further foamed and fused to each other to form the foamed molded article 4.

At this time, the steam is supplied from one lower end of the utility pipe 2 and the other lower end is opened or sucked to the atmosphere, so that the steam between the filled foamed resin particles b is formed. -The distribution of the program may be smooth. Further, depending on the shape of the composite molded body, the utility pipe 2 may be alternately connected to the vacuum device 18 and the steam supply source 16 at regular intervals.

Thereafter, the formed composite molded body 1 is cooled. As a cooling method, in addition to cooling from the conventional molding die 6, the vacuum devices 18, 1 from the utility pipe 2 are used.
8 to suck out condensed water.

Finally, as shown in FIG. 5, the mounting base 9 is lowered to separate the filling feeder 8 from the molding die 6, but the utility pipe 2 comes out of the utility pipe setting hole 28. And remains in the composite molded body 1. Then, the molding die 6 is opened, and the headrest 1, which is a composite molded body into which the utility pipe 2 is inserted, is taken out.

[0042]

According to the present invention, since the foamed molded body is formed before the hollow molded body is cooled and solidified, the boundary between the two is sufficiently thermally welded, so that the core material layer and the exterior material layer are firmly bonded. Is done. On the other hand, at the time of foam molding, since the foamed resin particles bite into the holes of the utility pipe due to the foaming pressure of the foamed resin particles,
The utility pipe serving as a stay and the core material layer are firmly connected.

Also, since the molding die used in the blow molding is used as it is in the foam molding, and the foaming pressure is suppressed by this molding die, it is not particularly necessary to use another molding die. At the same time, the two molding steps can be simplified to one step. Therefore, the molding apparatus can be simplified, the equipment cost can be reduced, and the production cost of the composite molded body can be reduced.

Further, by using a thermoplastic elastomer resin as a material of the hollow molded article, flexibility can be imparted to the exterior material layer, so that the comfort of the synthetic resin molded article for vehicles can be improved.

[Brief description of the drawings]

FIG. 1A is an external perspective view of a headrest when a composite molded article of the present invention is applied to a headrest,
(B) is the same longitudinal sectional view.

FIG. 2 is an external perspective view showing one embodiment of a utility pipe integrated with the composite molded body.

FIG. 3 is a schematic cross-sectional view of an apparatus for manufacturing a composite molded body, showing a state at the time of blow molding.

FIG. 4 is a diagram showing a state during foam molding.

FIG. 5 is a diagram showing a state when the mounting base is lowered.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Composite molded object 2 ... Utility pipe 3 ... Slit hole 4 ... Core material layer 5 ... Exterior material layer 6 ... Molding die a ... Parison b ... Expanded resin particles

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B29K 105: 04 105: 20 B29L 31:58 (72) Inventor Kazuhide Hattori 1000 Kawajiri-cho, Yokkaichi-shi, Mie Mitsubishi Oil (72) Inventor Hiroyuki Yamaji 1000 Kawajiri-cho, Yokkaichi-shi, Mie Prefecture Mitsubishi Petrochemical Birdish Co., Ltd. (56) References JP-A-59-109328 (JP, A) JP-A-2-144223 (JP) JP-A-1-301313 (JP, A) JP-A-1-71211 (JP, A) JP-A-60-108520 (JP, U) JP-B-3-56905 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 49/00-49/80 B29C 39/10 B29D 22/00

Claims (3)

(57) [Claims] 1. A hollow consisting molded body armor material layer composite molding forming the core layer of a foam molded body in a length
A composite molded body characterized in that a plurality of holes are drilled in the longitudinal direction and the circumferential direction, and the utility pipe used in molding the composite molded body is left in the composite molded body and integrated. 2. An exterior material layer comprising a hollow molded body, comprising a thermoplastic elastomer.
The composite molded article according to the above. 3. A parison suspended in a molding die,
A utility pipe formed by drilling a plurality of holes in the length direction and circumferential direction is inserted, air is blown from the utility pipe to form a hollow molded body, and then the hollow molded body is cooled and solidified. Before filling the hollow molded body with the foamed resin particles, steam is blown from the utility pipe to heat and fuse the foamed resin particles to form a foamed molded body, thereby forming a composite molded body. A method for producing a composite molded body, comprising cooling and solidifying one of the working pipes while remaining in the composite molded body, and releasing the composite molded body from a molding die.