JPH07195414A - Two-layer foam injection molding apparatus - Google Patents

Abstract

PURPOSE:To provide a two-layer foam injection molding apparatus capable of continuously and efficiently obtaining a foamed molded product having such a structure that a surface material wherein a skin layer is provided on the surface of a foamed layer is integrally formed on the single surface of a core material and having desired touch and a good surface by injection molding. CONSTITUTION:A core material is supplied to the space formed by the primary mold 14 of a fixed plate 2 and the other mold 16 on the primary mold side of a rotary plate 3 from a primary injection machine 10 to mold a core material 29. This core material is bonded to the other mold 16 to rotate a rotary body. The mold 16 having the core material left therein and the secondary mold 15 of a movable plate 4 is clamped and a foamable material is supplied to the space between the core material and the secondary mold 15 from a secondary injection machine 11. Thereafter, the movable plate 3 is moved by a predetermined distance at predetermined mold opening speed by a leveling cylinder 26 to expand the space. A foamed layer formed by foaming the foamable material and the skin layer being in contact with the secondary mold 15 are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an automobile interior panel (instrument panel, door panel, seat back panel, steering wheel, handle, etc.), furniture (chair seat, etc.), sundries (shoes, slippers, etc.). As described above, a two-layer foam obtained by injection molding a composite foam molded article in which a surface material having a cushioning foam layer on one surface of a core material made of a hard resin and a skin layer on the surface is integrally formed. The present invention relates to an injection molding apparatus, and more particularly, to an apparatus capable of continuously and efficiently obtaining a composite foam molded article having a desired feel and a good surface by controlling the foaming state of a foamable resin.

[0002]

2. Description of the Related Art Conventionally, as a foam injection molding method for obtaining a composite foam molded article of this type, a method disclosed in Japanese Patent Publication No. 51-8424 is known. This method involves injecting a foaming resin containing a foaming agent into the space of the mold held so that the mold can be opened, and then expanding the space by opening the mold to foam the resin, and the mold surface side. To obtain a foam-molded article having the skin layer which has been cooled and solidified, and the foam layer inside the mold. This foam injection molding method discloses a circuit configuration in which the mold opening speed can be changed for each injection by providing a flow rate control valve in the mold opening hydraulic circuit. It is not intended to change.

In recent years, attempts have been made to apply this foam injection molding method to the molding of the interior panel for automobiles described above. The reason is that the yield of the resin is high and continuous molding is possible as compared with a case where the skin layer is separately molded by a vacuum molding method or the like.

In particular, interior panels for automobiles are required to have a soft surface and a soft feel. In order to obtain this feel, selection of materials is also important, and a thermoplastic elastomer that has rubber elasticity at room temperature and is plasticizable at high temperature and capable of injection molding is used as a material for forming the skin layer and the foam layer. Tried to use.

[0005]

However, when the conventional foaming injection molding method is applied to molding of a thermoplastic elastomer or the like, the foaming ratio or the size of the foaming cell is not appropriate, and the desired feeling is obtained. At the same time, there was a problem that a molded product having a good surface condition could not be obtained.

Therefore, a foaming injection molding method has been studied, which can secure an appropriate expansion ratio and a state of foamed cells and can obtain a foamed molded product having a desired feel. And, based on the knowledge gained during many experiments,
By controlling the foaming by changing the mold opening speed (space expansion speed) during one shot, the foaming cell has an appropriate size, the foaming ratio is also appropriate, and it has a soft feel and grain transfer. A foam injection molding method capable of obtaining a foam molded article having excellent surface properties such as good properties has been devised and filed by the same applicant as the present application (unpublished).

Therefore, the present invention can appropriately put the above-mentioned foam injection molding method into practical use, and is particularly suitable for molding a mass-produced product such as an automobile interior panel.
It is an object of the present invention to provide a layer foam injection molding device.

[0008]

In order to achieve the above object, the present invention comprises a two-layer foam injection molding apparatus comprising a core layer made of a hard resin, a foam layer and a skin layer on the surface thereof. Molding foamed products with surface materials laminated 2
In a layer foam injection molding apparatus, a fixed plate to which one of the primary side molds for molding the core material is attached, and a core material that is opposed to the fixed plate and supplies the core material into one of the primary side molds. A primary-side injection machine, and a movable plate having one of a secondary-side mold for molding the surface material attached to the fixed plate and movably installed so as to advance and retreat toward the fixed plate, A secondary injection machine that is installed opposite to the movable plate and supplies a foam material into one of the secondary molds, and moves forward and backward in the direction toward the fixed plate between the fixed plate and the movable plate. The turntable is movably installed, and the turntable is provided with a pair of the other molds of the same shape at positions on both surfaces that can be closely adhered to one of the primary mold and one of the secondary mold. The rotatably mounted rotating body and the movable platen and the fixed platen are provided to enable mold opening. It said movable plate so as to enlarge the space between the retained said other mold and the one of the secondary side mold has a configuration that includes a leveling cylinder to separate with respect to the rotating disk in.

[0009]

In the first molding cycle, the movable platen and the rotary platen are moved in the direction of the fixed platen to form a mold between the male plate of the rotary platen and the female plate of the primary plate of the fixed plate, for example. The core material is supplied from the primary injection machine to the first cavity of the open space, and first, only the core material is formed. Subsequently, the movable platen and the rotary platen are moved in a direction away from the fixed platen to open the respective molds on the primary side and the secondary side, and then the rotary body is rotated by 180 ° to form a molded core. The male mold with the material still attached is directed toward the movable plate, that is, toward the secondary side. The same steps are repeated in the molding cycle from the second time. The movable platen and the rotary platen are moved toward the fixed platen so that the male dies on both sides of the rotary platen are brought into close contact with the female dies on the primary side and the secondary side, respectively. At the same time as supplying the foam material from the secondary injection machine to the second cavity in the space between the core material still attached to the male mold and the secondary female mold, the male mold and the primary female mold are simultaneously supplied. The core material is supplied from the primary-side injection machine to the first cavity in the space between and to form the core material. After that, when the movable platen is moved by a predetermined distance in the direction away from the rotary plate by the operation of the leveling cylinder, the space between the core member and the secondary side female die is increased, so that the pressure of the foam material is increased. Lowers below the foaming critical pressure, foaming occurs inside the foaming material to form a foaming layer, and the foaming material in the part in contact with the secondary side female mold cools and solidifies in the unfoamed state, resulting in a hard skin. A layer is formed. Therefore, it is possible to continuously manufacture with one device, and since the surface material and the core material are simultaneously molded, the production efficiency is remarkably improved. Moreover, since the space for foaming the foamed material is expanded by controlling the speed and stroke with high accuracy by the leveling cylinder, the foaming having a good appearance and feel due to the desired foaming ratio and the good surface condition. A molded product can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a partially cutaway side view of a two-layer foam injection molding apparatus of the present invention, and FIG. 2 shows a sectional view taken along the line AA of FIG.

First, in FIG. 1, a fixed platen 2 is fixed on a bed 1, and a rotary platen 3 and a movable platen 4 are both mounted by wheels 6 on a guide rail 3 laid on the bed 1. It is movably supported in the front-back direction, that is, in the left-right direction in FIG. On the fixed platen 2, four moving cylinders 7 are arranged in a rectangular shape so as to maintain equilibrium as clearly shown in FIG. 2, and a rod 7a of a piston 8 thereof is fixed and fixed. Threaded tie rods 9 respectively connected to the tips of the rods 7a extend rearward through the rotary disc 3 and the movable disc 4. The movable platen 4 is provided with an openable / closable half nut 12 which is detachably gripped by the screw at the tip of each tie rod 9, and the rotary plate 3 is provided with an intermediate part of each tie rod 9. An openable and closable half nut 13 is provided that holds the screw in a detachable manner. By driving the moving cylinder 7 after the half nuts 12 and 13 are closed by a driving device such as a hydraulic cylinder (not shown), the movable platen 4 and the rotary platen 3 move in the direction of moving forward and backward toward the fixed platen 2. To be done. Then, by opening / closing the half nut 13, it is possible to select the independent movement of the rotary disk 3 or the interlocking movement of the movable disk 4 and the rotary disk 3.

A primary side injection machine 10 for injecting a resin material for molding a core material in a molten state is installed facing the fixed platen 2. On the other hand, in the secondary side injection machine 11 for injecting the foam material for molding the surface material in a molten state, the wheels 11b are placed on the guide rails 5 facing the movable platen 4 and supported movably. At the same time, it moves together with the movable platen 4. Then, on the stationary platen 2, a primary-side female mold 14 is attached at a position facing the nozzle 10a of the primary injection machine 10. Further, on the movable platen 4, at a position facing the nozzle 11a of the secondary injection machine 11,
A secondary side female mold 15 is attached. On the other hand, male dies 16 and 17 of the same shape are attached to the turntable 3 at positions facing the female dies 14 and 15 on both surfaces thereof.

As shown in FIG. 2, the turntable 3 has a rotating body 20 having male dies 16 and 17 fixedly mounted on both sides thereof, and a rotating device 19 such as a rotary actuator rotates the rotating body 20 by 180 ° around a vertical axis. It is designed to be rotated by each rotation angle. Four tie rods 22 with screws are provided on the rotary plate 3 so as to penetrate through the fixed plate 2 in a rectangular shape so as to maintain equilibrium. Further, the openable and closable half nut 23 connected to the piston of the mold clamping cylinder 24 embedded in the fixed platen 2 can hold the screw of the tie rod 22. Therefore, the rotating cylinder 3 is moved closer to the stationary disk 2 by the moving cylinder 7 and the half nut 2
3 is closed and the mold clamping cylinder 24 is operated, the mold 1
Tightening between 4 and 16 is performed. Similarly, the movable platen 4 is also provided with a mold clamping cylinder 25 whose piston is connected to the half nut 12 described above. The movable cylinder 7 brings the movable platen 4 closer to the rotary plate 3 and the half nut 1
When the molds 3 and 12 are closed and the mold clamping cylinder 25 is operated, the molds 15 and 17 are clamped.

The movable platen 4 is provided with four leveling cylinders 26, which are one of the gist of the present invention, arranged in a rectangular shape so as to maintain balance, as clearly shown in FIG. The piston rod 27 of each leveling cylinder 26 is opposed to one surface of the turntable 3. The piston rod 27 comes into contact with and separates from the facing surface of the rotary disk 3 by the movement of the movable disk 4.

Next, FIG. 3 is a flow chart showing the steps of manufacturing a foam molded article by the two-layer foam injection molding apparatus having the above-described structure.
11 to FIG. This device can extremely efficiently produce a composite foamed molded product by repeating a molding cycle of a series of steps, but only in the first molding cycle, only a core material as a primary molded product is produced. That is, the movable platen 4 and the rotary platen 3 are moved to the fixed platen 2 side by the operation described later, and as shown in FIG. 3, the primary female mold 14, the male mold 16, and the secondary female mold 1 are moved.
5 and the male mold 17 are brought into close contact with each other and the mold is closed. Then, the core material of the thermoplastic resin is supplied from the primary injection machine 10 into the first cavity 28 formed by the dies 14 and 16 on the primary side, and the core material 29 as a primary molded product is molded.

When the above-mentioned molding is completed, as shown in FIG. 4, the rotary disk 3 is moved away from the fixed disk 2 while the molded core material 29 remains attached to the male mold 16. The platen 4 is separated from the rotary platen 3, and the mold 1 on the primary side is provided.
4, 16 and the secondary side dies 15, 17 are opened. After this state, when the rotary disk 3 is rotated 180 ° by driving the rotary device 19, as shown in FIG. 5, the core material 28 comes into the initial state of the molding cycle in which the core disk 28 faces the movable disk 4.

In the initial state of FIG. 5, the molding cycle of a series of steps of the above apparatus is started. First, the half nut 12 shown in FIG. 1 is closed by a driving device (not shown), and the movable platen 4 is connected to the tie rod 9 so as to move integrally. After that, the moving cylinder 7 operates so as to suck the piston 8, and along with the movement of the piston 8, the movable platen 4 is moved in the direction of the rotary plate 3 via the tie rod 9, and as shown in FIG. Next mold 16,
17 is closely attached and the mold is closed. At this time, the core material 29 and the secondary-side female die 15 form the second cavity 30.

Subsequently, the half nut 13 is closed by a driving device (not shown), and the rotary disc 3 is connected to the tie rod 9 so as to move integrally. After that, the movable platen 4 and the rotary platen 3 are both moved toward the fixed platen 2 by the suction operation of the moving cylinder 7, and as shown in FIG.
The molds 14 and 17 on the primary side are in close contact with each other and are closed by the mold clamping cylinder 24, and the molds 14 and 17 form a first cavity 28. The transition from the initial state to the state shown in FIG. 3 is also performed through the same process as in FIGS. 4 to 7 described above.

In the state shown in FIG. 7, high-pressure oil is introduced into the mold clamping cylinder 24, and a piston (not shown) applies a pressing force to the tie rod 22 to the right in the figure through the half nut 23. , The turntable 3 is pressed to the right,
The molds 14 and 17 on the primary side are clamped. Similarly,
High-pressure oil is also introduced into the mold clamping cylinder 25, and the piston (not shown) applies a pressing force to the right side of the figure to the tie rod 9 via the half nut 12, so that the movable platen 4 also moves to the right side of the figure. The molds 15 and 16 on the secondary side are clamped by being pressed in one direction.

Upon completion of the mold clamping, as shown in FIG. 8, a styrene-based elastomer containing a foam material is placed in the second cavity 30 formed by the core material 29 on the secondary side and the female mold 15 on the secondary side. The foam material 31 such as is injected and filled from the nozzle 11a of the secondary injection machine 11 at a predetermined injection pressure. At the same time, the first mold formed by the dies 14 and 17 on the primary side
A core material is supplied into the cavity 28 from the nozzle 10a of the primary injection machine 10 to simultaneously form a core material 29 as a primary molded product.

In the state of FIG. 8, the leveling cylinder 26 is set so as to exceed the hydraulic pressure of the left mold clamping cylinder 25.
When a hydraulic pressure is generated, the leveling force of the leveling cylinder 26 exceeds the pressure of the mold clamping cylinder 25. At this time, since the turntable 3 is fixed to the base 1 by the cotter 32, as shown in FIG.
The piston rod 27 of No. 6 is extended so that the movable platen 4, that is, the secondary-side female die 15 has a predetermined stroke t (for example, 4
mm) to the left, and the space of the second cavity 30 is increased accordingly. Therefore, the pressure of the foam material 31 is reduced to the foaming critical pressure or less, and foaming occurs inside the foam material 31 to form the foam layer 331. Further, the foam material 31 in the portion in contact with the male mold 15 is cooled and solidified in the unfoamed state, and the hard skin layer 33 remains unfoamed.
2 is formed.

The expansion speed of the space of the second cavity 30, that is, the mold opening speed of the secondary female mold 15 with respect to the male mold 16, is controlled by the leveling cylinder 26, for example.
Controlled to 2.0 m / sec with high accuracy. By setting this mold opening speed, it is possible to obtain a foam-molded article having a desired expansion ratio or skin layer 332 and a good surface condition. That is, when the mold opening speed is too high, the expansion ratio becomes high, the foam cells become large, the skin layer 332 becomes thick, and the foam layer 331 becomes extremely thin. vice versa,
If the mold opening speed is too low, the expansion ratio becomes low, the foam cells become small, the skin layer 332 becomes extremely thin, and the foam cells in the foam layer 331 become uneven. Therefore, in the present invention, since the mold opening speed can be controlled with high accuracy by using the leveling cylinder 26,
It is possible to obtain a desired favorable foamed molded product.

As shown in FIG. 9, a foam layer 33 is formed on the core material 29.
When the surface material 33 including 1 and the skin layer 332 is integrally laminated and formed, after removing the cotter 32, the half nut 23 is opened and the moving cylinder 7 is operated to extend the piston rod. Therefore, as shown in FIG. 10, the rotary disc 3 and the movable disc 4 are both moved to the left with the molded core material 29 left in the male die 17, and the dies 14 and 17 on the primary side are opened. To be done.

When the turntable 3 is moved to a predetermined position, the half nut 13 provided on the turntable 3 opens. Thereby,
As shown in FIG. 11, the movable platen 4 is further moved leftward by the extension of the piston rod 7a of the moving cylinder 7, and the molds 15 and 16 on the secondary side are opened. Then, the core material 2
9 and the surface material 33 are integrally laminated, and the male die 16
The foamed molded article 34 attached to the
When the rotating body 20 of the turntable 3 is rotated by 180 °, the initial state of FIG. 5 is reached, and the molding cycle is completed.

In this way, the core material 29 is attached to the male die 16 (1
7), the second cavity 30 is formed between the core material 29 and the secondary-side female die 15 to expand the space for filling the foam material 31 and foaming to cool and solidify. A surface material 33 including a foam layer 331 and a skin layer 332 is integrally laminated on the surface 29. Therefore, the composite foam molded article 34 including the core material 29 and the surface material 33 can be continuously manufactured by one molding apparatus, and the core material 2 can be manufactured.
Since 9 and the surface material 33 are molded at the same time, the production efficiency is remarkably improved.

In the case of a large apparatus that requires a large mold clamping force, a hydromechanical mold clamping apparatus is used as the mold clamping cylinders 24 and 25, and the stroke thereof sufficiently satisfies the foam mold opening stroke. If so, it is possible to reduce the required amount of oil in the case of a large size, and it is possible to obtain faster mold opening and closing.

[0027]

As described above, according to the two-layer foam injection molding apparatus of the present invention, the rotating body of the rotary disk is rotated while the core material molded by the primary injection machine is attached to the mold, and this direction is used. At the same time as supplying the foam material from the secondary injection machine to the second cavity in the space between the converted core material and the secondary mold,
Since the core material is molded by supplying the core material from the primary injection machine to the space between the primary molds of the rotating plate and the fixed plate, the composite foam molding consisting of the surface material and the core material. The product can be continuously manufactured by one device, and the surface material and the core material are simultaneously molded, so that the production efficiency is remarkably improved. Therefore, it is particularly suitable for molding mass-produced products such as automobile interior panels.

Moreover, the most important feature is that the movable platen is moved in the direction away from the rotary plate by the operation of the leveling cylinder, so that the foamed material is foamed between the secondary side female mold and the male mold to cool it. The second space that expands to solidify
The cavity can be formed by controlling the movable platen by a predetermined distance at a predetermined speed with high precision and moving it. Therefore, it is possible to obtain a foam-molded article having an excellent appearance and a soft feel due to a desired expansion ratio and a good surface condition.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a partially cutaway side view of the step of molding only the core material in the same apparatus.

FIG. 4 is a partially cutaway side view showing a state where the primary side and the secondary side are opened from the state of FIG.

FIG. 5 is a partially cutaway side view of the same apparatus in an initial state.

FIG. 6 is a partially cutaway side view showing a state where the secondary side of the same apparatus is closed.

FIG. 7 is a partially cutaway side view showing a state where the primary side of the above apparatus is closed.

FIG. 8 is a partially cutaway side view showing a state in which a molding material has been supplied to the primary and secondary sides of the above apparatus.

FIG. 9 is a partially cutaway side view of an essential part showing a state in which the foamed material is foamed in the same apparatus.

FIG. 10 is a partially cutaway side view showing a state where the primary side of the above apparatus is opened.

FIG. 11 is a partially cutaway side view showing a state where the secondary side of the same apparatus is opened.

[Explanation of symbols]

 2 Fixed plate 3 Rotating plate 4 Movable plate 7 Moving cylinder 9,22 Tie rod 10 Primary injection machine 11 Secondary injection machine 12,13,23 Half nut 14 Primary female mold (one primary mold) 15 2 Secondary female mold (one secondary mold) 16,17 Male mold (other primary and secondary mold) 20 Rotating body 24,25 Mold clamping cylinder 26 Leveling cylinder 29 Core material 31 Foam material 33 Surface material 34 Foam molded article 331 Foam layer 332 Skin layer

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Claims (1)

[Claims] 1. A two-layer foam injection molding apparatus for molding a foam molded article in which a surface material composed of a foam layer and a skin layer on the surface thereof is integrally laminated on a core material composed of a hard resin. A fixed platen to which one of the primary side molds for molding the core material is attached, a primary side injection machine which is installed opposite to the fixed platen and supplies the core material into one of the primary side molds, and the surface One of the secondary side molds for forming the material is attached to the fixed plate and is movably installed so as to move back and forth in the direction of the fixed plate, and the movable plate is installed opposite to the movable plate. A secondary injection machine that supplies a foam material into one of the secondary molds, and a rotary disk movably installed between the fixed disk and the movable disk so as to move back and forth toward the fixed disk. And the position of both sides that can be adhered to one of the primary side mold and one of the secondary side molds, respectively. And a rotating body rotatably mounted on the turntable, which includes a pair of the other molds having the same shape.
The movable plate is provided between the movable platen and the fixed platen, and the movable platen is provided on the rotary platen so as to expand the space between the other mold and the one of the secondary molds that are held so as to be opened. A two-layer foam injection molding device, comprising: a leveling cylinder which is separated from each other.