JP2007216532A - Foamed resin, interior part for automobile, and manufacturing method for foamed resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the strength of a molded article in a manufacturing method for a foamed resin which performs foam-molding by injecting a molten resin in a cavity 13 being formed between a movable die 12 and a fixed die 11. <P>SOLUTION: The contour of the cavity 13 includes the die surface (the first surface 31) of the movable die 12, and the distal end surface (the second surface 32) which is provided on the distal end of a movable jig 16 being provided on the movable die 12 side. When the movable die 12 separates from the fixed die 11 after the injecting of the molten resin into the cavity 13, the first surface 31 is made to step aside together with the movable die 12, and in the meantime, the second surface 32 is not made to step aside from the movable die 12. As a result, a foamed section 41 is constituted at a section facing the first surface 31 of the cavity 13, and a non-foamed section 42 is constituted at a section facing the second surface 32. The non-foamed section 42 is made into a reinforcing section. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a foamed resin used for, for example, automobile interior parts and a method for producing the same.

2. Description of the Related Art Conventionally, molded products having a part of foamed resin have been used for vehicle instrument panels and the like. For example, in Patent Document 1, as a molding method of a partially foamed molded product, (A) a method in which a foamed layer portion is formed as a separate product and attached to a panel body, or (B) a panel body A method is disclosed in which a skin material is set and foamed material is foamed in a space between the panel main body and the skin material formed after mold clamping and integrally molded.
JP-A-11-1981156 (0002)

  However, in the method disclosed in Patent Document 1, since the entire foamed resin is foamed, it is difficult to give strength to the foamed part itself, and there is still room for improvement in terms of stability of mounting dimensions. It was. Further, it is necessary to prepare a non-foamed material such as a panel main body for securing strength as a separate part, which has been a factor in increasing the production cost and the number of man-hours for the foamed resin.

  The present invention has been made in view of the above circumstances, and a main object thereof is to provide a foamed resin excellent in rigidity and a production method capable of producing such a foamed resin by a simple method. .

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the first aspect of the present invention, there is provided a foamed resin in which a foamed portion and a non-foamed portion coexist in the same resin, and the non-foamed portion is used as a resin reinforcing portion.

  With this configuration, it is possible to provide a foamed resin having excellent strength.

  In the said foamed resin, it is preferable to provide the said reinforcement part with the surface which contacts the fixing member for fixing the said foamed resin to another member.

  With this configuration, the foamed resin is prevented from being crushed or deformed by the fixing member, and the stability of the mounting dimension can be ensured.

  According to a second aspect of the present invention, there is provided an automobile interior part comprising the foamed resin.

  With this configuration, the strength required for the interior parts can be realized at a low cost.

  According to the 3rd viewpoint of this invention, the manufacturing method of the following foamed resins is provided. That is, the molten resin is injected into a cavity formed between the movable mold and the fixed mold and foam-molded. The outline of the cavity includes a first surface that retreats together with the movable mold when the movable mold leaves the fixed mold after the molten resin is injected into the cavity, and a retraction speed, a retraction distance, or a retraction of the first surface. And a second surface with different timing. A foamed portion is formed in a portion facing the first surface of the cavity, and a non-foamed portion is formed in a portion facing the second surface.

  By this method, the presence or degree of foaming can be varied between the first surface and the second surface, and a non-foamed portion can be formed in the same resin. As a result, a foamed resin having excellent strength can be produced.

  In the foamed resin manufacturing method, it is preferable that a movable jig is provided on the movable mold side, and the second surface is provided at a tip of the movable jig.

  By this method, the second surface can be easily moved by moving the movable jig with respect to the movable mold, and the presence / absence of foaming and the degree of foaming can be easily controlled.

  In the foamed resin manufacturing method, it is preferable that the retreat distance of the second surface is zero.

  By this method, the non-foamed portion can be formed reliably.

  In the manufacturing method of the said foamed resin, it is preferable to do as follows. That is, a movable jig is provided on the movable mold side, and the second surface is provided at the tip of the movable jig. When the movable mold is separated from the fixed mold after the molten resin is injected into the cavity, the movable jig is connected to the fixed mold so as not to be relatively movable.

  By this method, the retracting distance of the movable jig can be surely reduced to zero when the movable mold is retracted, so that the non-foamed portion can be more reliably formed.

  In the foamed resin manufacturing method, it is preferable that the second surface is positioned so as to be recessed from the first surface when viewed from the movable mold side when the molten resin is injected into the cavity.

  By this method, it is possible to secure a distance for retracting the first surface for foaming while ensuring that the portion corresponding to the second surface is not foamed.

  In the foamed resin manufacturing method, it is preferable that the second surface is positioned so as to be recessed from the first surface when viewed from the movable mold when the non-foamed portion of the molten resin is solidified.

  By this method, the reinforcing portion having a shape such that the non-foamed portion protrudes from the foamed portion can be formed, so that the strength can be effectively improved.

  Next, embodiments of the invention will be described. FIG. 1 is a schematic view of a mold apparatus for producing a door trim base material according to an embodiment of the present invention, and FIG. 2 is a view showing a state in which a molten foamed resin is supplied to the cavity from the state of FIG. 3 is a view showing a state in which the movable mold is retracted to partially foam the foamed resin. FIG. 4 is a view showing a state where a non-foamed portion of the partially foamed resin is fixed to the mounting bracket with a screw.

  FIG. 1 shows a schematic view of a mold apparatus. The mold apparatus 10 is for molding a door trim base material as one part of a door trim (automobile interior part). The mold apparatus 10 includes a fixed mold (cavity mold) 11 and a movable mold (core mold) 12, and a cavity 13 is formed between the fixed mold 11 and the movable mold 12. In the mold apparatus 10, a foamed resin in a molten state is supplied into the cavity 13, and necessary portions are foamed, cooled and solidified, then opened and released, and the door trim base material is formed. Is configured to get.

  The movable die 12 is formed with a through-hole holding hole 14 in the vertical direction, and a plurality of horizontal slide holes 15 are formed so as to be connected to the holding hole 14. The slide hole 15 is opened in the mold surface of the movable mold 12 (surface that forms the cavity 13). Further, the slide hole 15 is formed in an elongated hole shape elongated in the direction perpendicular to the paper surface of FIG.

  The movable mold 12 is provided with a movable jig 16 so as to be movable. The movable jig 16 is arranged in a vertical direction and is projected from the base 17 toward the cavity 13 while being inserted into the holding hole 14, and is slid into the slide hole 15. And a plurality of elongated protrusions 18 that are movably inserted. The convex portion 18 is formed in an elongated shape in the direction perpendicular to the paper surface of FIG.

  With this configuration, in the mold closed state of FIG. 1, the tip surface (second surface 32) of the convex portion 18 is closer to the inner side of the slide hole 15 than the mold surface (first surface) of the movable mold 12. It is in the retracted position. In other words, the second surface 32 is positioned so as to be recessed from the first surface 31 when viewed from the movable mold 12. In this state, molten resin is injected into the cavity 13.

  The upper and lower ends of the base portion 17 are bent vertically so as to approach the fixed mold 11, and a pin 20 protruding from the fixed mold 11 is inserted into a connecting hole 19 formed at the tip. The pin 20 moves so as to be retracted into the fixed mold 11 as necessary, and is configured to be able to be removed from the connecting hole 19.

  With the above configuration, in the mold closed state shown in FIG. 1, the molten foamed resin is supplied into the cavity 13 from an unillustrated gate to obtain the state shown in FIG. Then, at a stage before the molten resin is solidified, the movable mold 12 is retracted by a predetermined distance in a direction away from the fixed mold 11 (core back). Therefore, the mold surface (first surface 31) of the movable mold 12 is separated from the fixed mold 11 together with the movable mold 12.

  On the other hand, since the connecting hole 19 of the movable jig 16 is fixed (locked) by the pin 20 on the fixed mold 11 side, the movable jig 16 does not move relative to the fixed mold 11. Therefore, the tip surface (second surface 32) of the movable jig 16 does not move in the direction away from the fixed mold 11 (the retreat distance is zero).

  Accordingly, since only the portion of the cavity 13 that faces the first surface 31 is decompressed, the molten resin in the portion is foamed or gas-foamed by the chemical foaming agent, and as shown in FIG. Is formed. On the other hand, a portion facing the second surface 32 is a non-foamed portion 42.

  In the present embodiment, the movable mold 12 is retracted until the first surface 31 is flush with the second surface 32. Then, after cooling and solidifying in this state, the pin 20 is retracted to release the connection between the movable jig 16 and the fixed mold 11, the mold is opened, and the door trim base material 40 is taken out.

  As shown in FIG. 3, the door trim base 40 formed in this way has a partially foamed structure in which a foamed portion 41 and a non-foamed portion 42 coexist in the same resin. Therefore, as compared with the case where the whole is foamed uniformly (total foamed product), the increase in weight can be suppressed and the rigidity can be effectively improved.

  The above findings are supported by the following confirmation experiment conducted by the inventors of the present application. In this experiment, PPC (polypropylene resin filled with 20% talc) used as the core material for automobile interior parts (for example, instrument panels) was used for foam-free products and all foamed 1.4 times. A foamed product and a partially foamed product (this embodiment) in which linear non-foamed portions each having a width of 5 mm were formed at intervals of 80 mm were manufactured, and the strength was examined. The non-foamed product, the fully foamed product, and the partially foamed product were each 3 mm thick.

  Then, the bending elastic gradient of the non-foamed product (load with respect to the unit deformation amount) was 2.03 N / mm, the total foamed product was 1.43 N / mm, and the partially foamed product was 1.86 N / mm. Further, when the weights of the partially foamed product and the fully foamed product were compared, the partially foamed product showed an increase of about 2.3% in weight compared to the fully foamed product.

  That is, the partially foamed product of the present embodiment was able to realize a 30% improvement in rigidity compared to the fully foamed product, while the weight increase with respect to the fully foamed product could be suppressed to about 2%.

  FIG. 4 shows an example of attaching a synthetic resin having a partially foamed structure. In this attachment example, the non-foamed portion 42 (the second surface 32) is set at a position corresponding to a portion for fixing the door trim base material 40 to another member, whereby the strength of the portion is locally increased. Can be improved. FIG. 4 shows an example in which the door trim base material 40 is fastened to the mounting bracket 45 by using a screw (fixing member) 46, and the seat surface on which the head of the screw 46 sits or the surface in contact with the mounting bracket 45 is shown. By disposing the non-foamed portion 42, the contact surface with the seat surface and the mounting bracket 45 is not crushed, and the strength of the mounting portion and the stability of the mounting dimensions can be greatly improved.

  As described above, the door trim base material 40 of the present embodiment allows the portion 41 and the non-foamed portion 42 that are foamed in the same resin to coexist, and the non-foamed portion 42 is a resin reinforcing portion. Made of foamed resin. Therefore, it is possible to provide the foamed resin or the door trim base material 40 having excellent strength at a low cost.

  In the example of FIG. 4, the non-foamed portion 42 serving as the reinforcing portion is provided with a surface on which a screw 46 for fixing the foamed resin (door trim base material 40) to the mounting bracket 45 is brought into contact. Thereby, it is avoided that the door trim base material 40 is crushed or deformed by tightening the screws 46, and the stability of the mounting dimensions can be ensured.

  Further, as shown in FIG. 3, the mold apparatus 10 is configured to inject a molten resin into a cavity 13 formed between the movable mold 12 and the fixed mold 11 and perform foam molding. The contour of the cavity 13 is such that the first surface 31 (the mold surface of the movable mold 12) retreats with the movable mold 12 when the movable mold 12 leaves the fixed mold 11 after the molten resin is injected into the cavity 13. ) And a second surface 32 (a tip surface of the movable jig 16) having a different retraction distance from the first surface 31. A foamed portion 41 is formed in a portion facing the first surface 31 of the cavity 13, and a non-foamed portion 42 is formed in a portion facing the second surface 32.

  Thereby, the presence or absence of foaming can be made different between the part facing the first surface 31 and the part facing the second surface 32, and the foamed part 41 and the non-foamed part 42 coexist in the same resin. Can do. As a result, a foamed resin having excellent strength can be produced.

  In the present embodiment, the movable jig 16 is provided on the movable mold 12 side, and the second surface 32 is provided at the tip of the movable jig 16. Accordingly, since the second surface 32 can be easily moved by moving the movable jig 16 relative to the movable mold 12, the presence or absence of foaming and the degree of foaming can be easily controlled.

  Furthermore, in this embodiment, the retreat distance of the second surface 32 is set to zero. Therefore, the non-foamed portion 42 can be reliably formed.

  Further, in the present embodiment, when the movable mold 12 is separated from the fixed mold 11 after the molten resin is injected into the cavity 13, the movable jig 16 moves the pin 20 and the connection hole 19 with respect to the fixed mold 11. It is comprised so that relative movement is impossible. Therefore, since the retracting distance of the movable jig 16 (second surface 32) can be surely zero when the movable mold 12 (first surface 31) is retracted, a non-foamed portion can be reliably formed.

  In the present embodiment, when the molten resin is injected into the cavity 13 (FIG. 2), the second surface 32 is positioned so as to be recessed from the first surface 31 when viewed from the movable mold 12 side. Therefore, it is possible to secure a distance for retracting the first surface 31 for foaming as shown in FIG. 3 while ensuring that the portion corresponding to the second surface 32 is not foamed.

  In addition, as shown in FIG. 5, the non-foamed portion 42 can be formed by protruding from the door trim base material 40 like a protruding rib. In this method, first, from the state shown in FIG. 2, the movable jig 12 is moved by an appropriate distance in the direction away from the fixed mold 11 while the movable jig 16 is locked to the fixed mold 11 by the pin 20. As a result, the portion of the molten resin that faces the first surface 31 foams to become the foamed portion 41, and the portion that faces the second surface 32 becomes the non-foamed portion 42. However, at this time, the retracted distance of the movable mold 12 is made smaller than that in the case of FIG. 3, and the second surface 32 is positioned so as to be recessed from the first surface 31 when the movable mold 12 is moved as viewed from the movable mold 12 side. Keep it. This recessed depth corresponds to the protruding height of the rib-like non-foamed portion 42 during solidification.

  In this state, the movable mold 12 side is cooled by an appropriate method such as flowing cooling water, and the non-foamed portion 42 is cooled and solidified. By doing so, the non-foamed portion 42 is formed in a protruding shape and can be used as a reinforcing rib (reinforcing portion). However, at this time, the side facing the fixed mold 11 is appropriately heated to prevent solidification.

  Thereafter, the connection between the pin 20 and the connection hole 19 is released (unlocked), and the movable die 12 is retracted from the fixed die 11 together with the movable jig 16 by an appropriate distance so that the portion facing the fixed die 11 is first Foaming is possible regardless of the surface 31 and the second surface 32, and the entire surface on the fixed mold 11 side can be foamed as shown in FIG.

  As described above, the root portion of the projecting rib-like non-foamed portion 42 is partially embedded in the foamed portion 41 by making both the retracted distance and the retracted timing different between the first surface 31 and the second surface 32. The door trim base material 40 having such a configuration can be obtained. The door trim base material 40 can improve the rigidity as compared with the whole foamed product, and also has a good appearance because the surface on the fixed mold 11 side can be uniformly foamed as compared with the case of FIG. .

  Thus, in the manufacturing method shown in FIG. 5, when the non-foamed portion 42 of the molten resin is solidified, the second surface 32 is positioned so as to be recessed from the first surface 31 when viewed from the movable mold 12. Yes. Therefore, the non-foamed portion 42 can be formed in a protruding shape like a protruding rib, and the strength of the door trim base 40 can be effectively improved.

  Although the preferred embodiment and the modification of the present invention have been described above, the above configuration is an example, and can be modified as follows, for example.

  The non-foamed portion 42 as the reinforcing portion is not limited to an elongated shape or a rib shape, but can be changed to an arbitrary shape such as a columnar shape.

  The retraction distance of the second surface 32 can be made equal to the retraction distance of the first surface 31, and only the retraction timing can be varied. Alternatively, the second surface 32 and the first surface 31 can be configured to have different retraction speeds. Also by the above methods, the presence or absence of foaming and the degree of foaming can be varied.

  The synthetic resin molded product formed as described above can be used for other automobile interior parts other than the door trim base material 40, such as an instrument panel.

The schematic diagram of the metal mold | die apparatus for manufacturing the door trim base material which concerns on one Embodiment of this invention. The figure which shows a mode that the foamed resin of the molten state was supplied to the cavity from the state of FIG. The figure which shows a mode that the movable mold | type was evacuated and foamed resin was partially foamed. The figure which shows a mode that the non-foamed part of partially foamed resin was fixed to the attachment bracket with the screw. The figure which shows the modification which retreats a movable jig and forms a foaming part in one surface of a fixed mold | type side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold apparatus 11 Fixed mold 12 Movable mold 13 Cavity 16 Movable jig 31 Movable mold surface (first surface)
32 Front end surface of movable jig (second surface)
41 Foamed part 42 Non-foamed part

Claims (9)

  A foamed resin characterized in that a foamed part and a non-foamed part coexist in the same resin, and the non-foamed part is used as a reinforcing part of the resin.   2. The foamed resin according to claim 1, wherein the reinforcing portion is provided with a surface that contacts a fixing member for fixing the foamed resin to another member.   An automotive interior part comprising the foamed resin according to claim 1. In a method for producing a foamed resin in which a molten resin is injected into a cavity formed between a movable mold and a fixed mold and foamed,
The outline of the cavity includes a first surface that retreats together with the movable mold when the movable mold leaves the fixed mold after the molten resin is injected into the cavity, and a retraction speed, a retraction distance, or a retraction of the first surface. A second surface that is different in at least one of the timings,
A method for producing a foamed resin, comprising: forming a foamed portion in a portion facing the first surface of the cavity; and forming a non-foamed portion in a portion facing the second surface.   5. The method for producing a foamed resin according to claim 4, wherein a movable jig is provided on the movable mold side, and the second surface is provided at a tip of the movable jig. Production method.   5. The method for producing a foamed resin according to claim 4, wherein the retreat distance of the second surface is zero. It is a manufacturing method of the foamed resin of Claim 6, Comprising:
A movable jig is provided on the movable mold side, and the second surface is provided at the tip of the movable jig,
The foamed resin manufacturing method, wherein the movable jig is connected to the fixed mold so as not to move relative to the fixed mold when the movable mold leaves the fixed mold after the molten resin is injected into the cavity. A method for producing a foamed resin according to any one of claims 4 to 7,
A method for producing a foamed resin, characterized in that when the molten resin is injected into the cavity, the second surface is positioned so as to be recessed from the first surface when viewed from the movable mold. A method for producing a foamed resin according to any one of claims 4 to 8,
A method for producing a foamed resin, wherein the second surface is positioned so as to be recessed from the first surface when viewed from the movable mold when the non-foamed portion of the molten resin is solidified.

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