JPH11129275A - Production of internal molding foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing internal molded foam in which no production from the surface of molded foam is formed at a position corresponding to a steam hole in the surface of the molded foam. SOLUTION: In a method for producing foam in which steam is introduced into the cavity 3 of a mold consisting of a cover mold 1 and a movable half 2 which is formed by attaching a seam hole forming member 4 having a steam passage hole to a through hole 12 to fusion-bond synthetic resin foam beads together, the opening of the steam passage hole in the member 4 is positioned to face the cavity 3, the end of the member 4 is protruded from mold inner wall surfaces 6a, 7a to the cavity 3 side. In this state, the mold is installed for molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an in-mold molded foam.

[0002]

2. Description of the Related Art In-mold molded foams produced from foamed synthetic resin beads are often made of a metal mold provided with a steam hole directly or a metal member provided with a steam hole forming member having a steam passage hole in a through hole. After filling the foam beads into the cavities of the molds using a mold, steam is introduced into the mold through a steam hole or a steam passage hole (hereinafter, referred to as a steam hole or the like), and the foam beads are mutually exchanged by the steam. Molding for fusion bonding is performed to obtain a molded body having a mold cavity shape, followed by cooling. Thereafter, the molded foam is taken out of the mold, and the molded foam is dried and / or cured to obtain a product.

[0003]

However, traces of vapor holes and the like are formed as burr-like projections on the surface of the in-mold molded foam produced by the above method. This is presumably because the expanded beads expand during the molding and penetrate into the inside of the vapor hole or the like. The height of the protrusion may be as high as about 1 mm, and the tip may be formed as a protrusion protruding from the surface of the molded foam.

[0004] When the molded foam having the protruding portion is covered with a thin surface material such as synthetic resin or synthetic leather in close contact with the surface of the molded foam, the protruding portion is reflected on the thin foam material. There is a drawback in that a protrusion is generated on the surface of the glass and the appearance is deteriorated.

[0005] Further, when the molded foam having the protruding portion is used as a so-called robot tray, which is used for storing and taking out electronic parts of precision equipment by using a robot, There is also a drawback that the above-mentioned protruding portion causes a trouble because the robot cannot store the electronic component in a predetermined position.

A robot for storing electronic components and the like at a predetermined position is, for example, an operation of holding and moving an electronic component at a certain place and arranging it at another place.
The following configuration is used to prevent damage to electronic components and to prevent mixing of different components. That is, as an example, in the position after the movement, the height of the electronic component in the holding state with respect to the place where the electronic component is to be released and arranged is configured to not release the electronic component unless it is a predetermined height. I have. As another example, at the position after the movement, the horizontal distance of the held electronic component to the place where the electronic component is to be released and arranged is configured to not release the electronic component unless the horizontal distance is a predetermined distance. ing.

In the case where the robot having the former configuration is used, when a robot tray made of a molded foam formed so that the protruding portion is directed upward is used, the above-mentioned electronic component is located at a place where the electronic component should be released. Because of the protrusion, the robot does not release the electronic component by sensing that the height of the held electronic component with respect to the place to be released and placed is lower than a predetermined height. Further, when a robot having the latter configuration is used, when a robot tray made of a molded foam formed so that the protrusions are oriented in the lateral direction is used, the protrusions are provided at places where electronic components should be dropped. For this reason, the robot does not release the electronic component by detecting that the horizontal distance of the held electronic component to the place where the electronic component should be released and placed is shorter than a predetermined distance. As described above, a molded foam having a protruding portion from the surface cannot provide information on a correct position to the robot, so that the robot cannot accurately position or operate, or cause a malfunction, resulting in a robot tray. Could not be used as.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide an in-mold molded foam in which a protrusion from the molded foam surface is not formed at a position corresponding to a steam hole on the molded foam surface. An object of the present invention is to provide a method for producing an in-mold molded foam from which a body can be obtained.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided (1) after filling a synthetic resin foam bead into a cavity of a mold having a vapor hole forming member having a vapor passage hole attached to the through hole, and then forming the vapor hole forming member. Steam is introduced into the cavity of the mold through a steam passage hole, a molding is performed to fuse the synthetic resin foam beads to each other, and then a step of cooling is performed. The molding is performed with the opening of the steam passage hole in the steam hole forming member facing the mold cavity and the tip of the steam hole forming member projecting toward the cavity from the inner wall surface of the mold. (2) The inner wall surface of the mold at the tip so that the height of the tip of the steam hole forming member from the inner wall surface of the mold toward the cavity does not become lower than a predetermined height. Caught on (1) The method for producing an in-mold molded foam according to the above (1), wherein the molding is performed using a metal mold provided with a steam hole forming member provided with a recess. The area inside the outer contour of the surface is larger than the opening area of the mounting through hole of the mold for the steam hole forming member to the mold cavity side, and a flange portion is formed around the distal end portion of the steam hole forming member. (2) The method for producing an in-mold molded foam according to the above (2) using a steam hole forming member in which the flange portion is configured as a hook portion, and (4) a cavity side from a mold inner wall surface at the tip of the steam hole forming member. A mold in which a steam hole forming member is attached to a through hole provided with a protrusion to which a rear end of the steam hole forming member can be abutted so that a projecting height of the steam hole forming member does not become lower than a predetermined height. The mold according to the above (1), which is molded by using The method for producing a molded foam and gist.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a mold used in the method for producing an in-mold molded foam of the present invention, and FIG. 2 is an enlarged view of a main part of FIG. In the figure, 1 is a fixed mold, 2 is a movable mold, and 3 is a cavity. 4 is a steam hole forming member, and 5 is a steam passage hole. The mold used in the manufacturing method of the present invention usually includes a fixed mold 1 and a movable mold 2 as shown in FIGS. 1 and 2, and when the fixed mold 1 and the movable mold 2 are brought into contact with each other. A cavity 3 is formed between the molds 1 and 2. Each of the fixed mold 1 and the movable mold 2 has a double-wall structure having inner walls 6 and 7 facing the cavity and outer walls 8 and 9 other than the inner walls.
Spaces 10 and 11 surrounded by an inner wall and an outer wall of each type are provided.

A through hole 12 is formed in the inner wall 6 of the fixed mold 1 and the inner wall 7 of the movable mold 2, and a steam hole forming member 4 having a steam passage hole 5 is fitted into the through hole 12 and its tip end. 4a is mounted so as to protrude from the cavity side surfaces 6a and 7a of the inner walls 6 and 7 toward the cavity 3, and one opening 5a of the steam passage hole 5 is
It is located facing. The other opening 5b of the steam passage hole 5 is arranged toward the spaces 10 and 11, and the inner space of the steam passage hole 5 is formed through the spaces 10 and 11 through the outer walls 8 and 9 communicates with the inner space of the steam supply pipes 13 and 14 attached to the pipe 9.

FIG. 3 is an oblique sectional view showing the steam hole forming member 4 in FIG. The steam hole forming member 4 generally has a substantially cylindrical shape whose outer shape is closed at one end, and has, for example, a cylindrical shape whose outer shape is closed at one end as shown in FIG. Openings 5 on both sides of the closure wall at the side edges
A vapor permeable hole 5 having a circular cross section having a and 5b or a slit-shaped hole (not shown) is provided.

FIG. 4 is a perspective view showing another example of the steam hole forming member. When the steam hole forming member 4 of FIG. 4 is attached to the mold as described above,
a, 7a, so that the projecting height from the cavity 3 side does not become lower than a predetermined height.
The hook 15 is provided on the inner wall surface of the mold b.

In FIG. 4, the area within the outer contour in the cross section near the tip 4b of the steam hole forming member 4 is the through hole 1
2 is larger than the opening area to the mold cavity side, and the catching portion 15 is formed of a flange-like portion 16 formed in an annular shape around the distal end portion 4 b of the steam hole forming member 4. Is not limited to such an embodiment, and the catch portion may be formed by discontinuous projections. However, it is preferable that the hook 15 is formed of a continuous protrusion such as an annular shape. The reason is as follows.

In the present invention, the size of the steam hole forming member 4 is made slightly larger than the through hole 12 so that the steam hole forming member 4 does not easily fall out of the through hole 12 during molding. In advance, the steam hole forming member 4 is driven into the through hole 12 from the cavity side, and a mold fitted and fixed using the above partially large portion is used. Normally, the through-hole 12 is formed to have a perfectly circular cross-section, and the major axis of the through-hole 12 is slightly larger than the diameter of the through-hole 12, and the minor axis is slightly smaller than the diameter of the through-hole 12. For example, a member formed into a shape such as an elliptical cross section is driven in and fixed. Therefore, a small gap may be formed between the outer wall of the steam hole forming member 4 and the inner wall of the short diameter portion of the through hole 12. In the embodiments shown in FIGS. 2, 3, and 9, when molding is performed in a state in which a gap is formed between the outer wall of the steam hole forming member and the inner wall of the through hole, the foamed resin easily enters the gap. As a result, the resulting molded foam may have small burr-like projections protruding from the surface thereof. On the other hand, in the embodiments shown in FIGS. 4 to 7, even if molding is performed in a state where a gap is formed between the outer wall of the steam hole forming member and the inner wall of the through hole, the foaming is caused by the presence of the flange 16. The resin does not enter the gap, and no burr-like projections protruding from the surface of the molded foam are formed. However, this is because the collar-shaped portion 16 as the hooking portion 15 has a form of a projection formed in a continuous shape such as an annular shape. When the hooking portion 15 is formed of a discontinuous projection, There is a risk that burr-like projections will occur. Hook part 1
It is for this reason that a continuous projection is preferred as 5.

FIG. 5 is a cross-sectional view of a main part of the movable mold 2 side of the mold to which the steam hole forming member of FIG. 4 is attached. Since the hook 15 formed of the flange 16 formed at the tip 4b of the steam hole forming member 4 is hooked on the inner wall surface 7a of the mold, the cavity 3 is increased by the internal pressure that increases during molding.
It can be used for molding any number of times without being pushed from the side to the space 11 side and retracting in the space 11 direction.
Although the fixed mold 1 side is not shown, the fixed mold 1 side has the same operation as the movable mold 2 side as described above with reference to FIG.

FIG. 6 is a perspective view showing another embodiment of the steam hole forming member, and FIG. 7 is a sectional view showing a mold to which the steam hole forming member of FIG. 6 is attached. As shown in FIG. 7, as the steam hole forming member 4 having the hook portion 15 formed at the front end, it is preferable that the surface of the front end 4a is formed into a curved surface. FIG.
FIG. 8 is a cross-sectional view showing the surface shape of the molded foam when the mold shown in FIG. 7 is used. If a mold equipped with such a steam hole forming member is used,
The corner 18 formed at the opening edge of the concave portion 17 corresponding to the projecting portion into the cavity by the tip 4b of the steam hole forming member formed in the obtained molded foam A is relatively smooth and less noticeable. There are advantages. Also, when the steam hole forming member 4 as described above is attached to the inner wall surface along the mold moving direction (the moving direction of the moving mold 2 and the horizontal direction in the figure) in the molds 1 and 2 shown in FIG. In addition, there is an advantage that the molded foam can be easily released without being caught by the mold, the molded foam can be easily taken out from the mold, and the molded foam can be prevented from being cracked or chipped.

As shown in FIG. 9, in order to prevent the projecting height of the distal end of the steam hole forming member from the inner wall surface of the mold toward the cavity from becoming lower than a predetermined height, as shown in FIG. In the mounting through-hole 12, a projection 19 can be provided that can restrict the retreating movement of the steam hole forming member 4 by abutting the rear end 4c of the steam hole forming member 4 thereon. However, as described above, the flange portion 1 is attached to the distal end portion 4b.
It is preferable to provide a hook 15 formed of a protrusion 6 or a protrusion.

As described above, if the steam hole forming member 4 is configured not to recede from the cavity 3 side to the inside of the mold, the steam hole forming member is moved from the cavity side to the metal side by the internal pressure of the cavity at the time of molding the expanded beads. It can be used for molding in a state where the tip of the steam hole forming member is protruded toward the cavity side repeatedly without retreating to the inside of the mold for a long period of time.

In any of the above embodiments, the height of the steam hole forming member 4 protruding from the mold inner wall surfaces 6a, 7a toward the cavity 3 depends on the magnitude of the secondary foaming force of the foam particles used, Although it depends on the diameter or width of the steam passage hole 5, when the diameter or width of the steam passage hole 5 is 0.1 to 1.0 mm,
It is desirable to adjust the distance a from the tip of each steam passage hole 5 of the steam hole forming member 4 to the inner wall surface of the mold to be 0.5 to 1.5 mm.

In the present invention, the steam hole forming member 4 is not limited to a cylindrical shape having an externally closed one end, but may have a columnar external shape. Further, the outer shape may be a polygonal cylindrical shape or a polygonal column shape with one end closed.

In the above embodiment, the mold 3 is
Although a mold having a double-walled structure is shown, in the present invention, a mold having a structure in which a cavity is formed when both molds are brought into contact with each other, including a fixed mold and a movable mold, may be used. It is not limited to a mold having a double wall structure.

The method for producing an in-mold molded foam according to the present invention uses a mold in which the above-described steam hole forming member is attached to a mold provided with an attachment through hole as described above, and the cavity of the mold is used. Is filled with synthetic resin foam beads, then the mold is completely closed, and then this state is maintained with the tip of the steam hole forming member protruding from the inner wall surface of the mold toward the cavity side. Steam is introduced into the cavity of the mold through the steam passage hole, and the foam beads are fused and integrated by the steam to form an in-mold molded foam having the shape of the mold cavity. It is opened to take out the molded foam from the mold and then dried as required, or further cured under predetermined conditions to obtain a product.

In the present invention, the molding is specifically performed as shown in FIG. 1, FIG. 2, FIG. 5, FIG. 7, and FIG.
Of the steam hole forming member 4 is made to protrude from the mold inner wall surfaces 6a, 7a toward the cavity 3 side. It is sufficient only at unfavorable or problematic locations that the formed burr-like projections protrude from the surface of the molded foam. However, the tips of all the steam hole forming members 4 may be projected toward the cavity 3 side. In particular, when it is not desired to form undesired burr-like projections on the entire surface of the molded foam, it is needless to say that the tips of all the steam hole forming members 4 are projected to the cavity 3 side. It is preferable that the molding is performed with the tip 20a of the illustrated feeder (filler for foam beads) 20 and the tip of an eject pin (not shown) protruding toward the cavity 3 by an arbitrary distance.

As a mold used for molding, the mold shown in FIG. 7 is used, and the molded foam obtained by the above method is, as shown in FIG.
No protruding part is formed. That is, the depth of the recess 17 formed corresponding to the protruding portion of the tip of the steam hole forming member is larger than the height of the burr-shaped protrusion 22 which is the trace of the steam hole, and the tip of the burr-shaped protrusion 22 is formed. 22 a does not protrude outward from the surface 21 a of the molded foam 21.

Therefore, in the molded foam obtained by the production method of the present invention, even if the burr-like projections are formed so as to enter the steam passage holes of the steam hole forming member, the burr-like projections are not formed. The projection is located within the depth of the recess, and the tip of the projection does not protrude outside the recess. Therefore, for example, even if a thin covering material is stretched on the molded foam, no protrusion due to the projection of the tip of the burr-like projection is formed on the surface of the covering material, and the surface of the covering material is flat. Thus, it is possible to provide a surface-covered material with a beautiful appearance, and it is suitable for manufacturing a molded foam used as a core material of a product to which the surface-covering material is stretched, such as an automobile sun visor.

The dents and depressions do not matter,
Products, semi-finished products, and automation lines that are incorporated in automation lines such as automatic packaging lines and automatic assembly lines, including positioning devices, where the presence of protruding parts from flat surfaces hinders accurate positioning and automatic operation It is also suitable for manufacturing a robot tray or the like used as a part of the device parts.

[0028]

As described above, the method for producing an in-mold molded foam of the present invention is constituted as described above, and therefore, a mold in which a protrusion from the surface of the molded foam is not formed at a position corresponding to a steam hole on the surface of the molded foam. An internally molded foam can be obtained. Therefore, by applying the present invention to the manufacture of a core material of a product to which the surface covering material is stretched, it is possible to obtain a surface covering material with a beautiful appearance. In addition, by applying to the manufacture of parts such as equipment and robot trays incorporated in the automation line, and semi-finished products assembled in the automation line, products that can operate the automation line smoothly and perform the desired work accurately without trouble Can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a mold used in the method of manufacturing an in-mold molded foam of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a perspective view showing a steam hole forming member in the mold shown in FIG.

FIG. 4 is a perspective view showing another example of the steam hole forming member.

FIG. 5 is a sectional view showing a mold to which the steam hole forming member shown in FIG. 4 is attached.

FIG. 6 is a perspective view showing still another example of the steam hole forming member.

FIG. 7 is a sectional view showing a mold to which the steam hole forming member shown in FIG. 6 is attached.

8 is a cross-sectional view showing a main part of a molded foam formed by the mold shown in FIG.

FIG. 9 is a cross-sectional view showing another example of a mold used in the method for producing an in-mold molded foam of the present invention.

FIG. 10 is a fragmentary cross-sectional view of a molded foam obtained by the method for producing an in-mold molded foam of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed type 2 Moving type 3 Cavity 4 Steam hole forming member 5 Steam passage hole 5a Opening 6 Fixed inner wall 6a Fixed inner wall surface 7 Moving inner wall 7a Moving inner wall surface 12 Through hole

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 04

Claims (4)

[Claims] 1. After filling a synthetic resin foam bead into a cavity of a mold in which a steam hole forming member having a steam passage hole is attached to a through hole, the cavity is passed through the steam passage hole of the steam hole forming member to form a mold cavity. In a method for producing an in-mold molded foam, comprising a step of introducing steam to fuse the synthetic resin foam beads to each other, and then cooling, an opening of a steam passage hole in a steam hole forming member of the mold is provided. A method for producing an in-mold molded foam, characterized in that molding is performed in a state in which a portion is positioned facing a mold cavity and a tip of a steam hole forming member is protruded toward a cavity side from an inner wall surface of the mold. 2. A steam provided with a hook portion on the inner wall surface of the mold so that the height of the distal end of the steam hole forming member from the inner wall surface of the mold toward the cavity does not become lower than a predetermined height. The method for producing an in-mold molded foam according to claim 1, wherein molding is performed using a mold to which the hole forming member is attached. 3. The steam hole forming member according to claim 1, wherein the area inside the outer contour in the cross section near the tip end of the steam hole forming member is larger than the opening area of the mounting through hole of the mold into the mold cavity side toward the mold cavity. The method for producing an in-mold molded foam according to claim 2, wherein a flange-shaped portion is formed around a distal end portion of the member, and the flange-shaped portion is configured as a hook portion using a steam hole forming member. 4. The steam hole forming member is provided with a rear end inside the steam hole forming member so that the projecting height of the front end of the steam hole forming member from the inner wall surface of the mold toward the cavity does not become lower than a predetermined height. The method for producing an in-mold molded foam according to claim 1, wherein the molding is performed using a mold attached to a through hole provided with a protruding portion that can be abutted.