JP2007223282A - Resin molding, and its molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce no crack on a barrier of a solid region portion with an expanding region portion. <P>SOLUTION: A panel-like carrier plate 9 comprises the expanding region portion A of a plate body 15 in which a surface skin 39 having a high resin density is formed on the surface by an expansion of a cavity volume in molding to expand a fiberfil thermoplastic resin, and at the same time, an expansion layer 41 having many pores and having a lower resin density as compared to the surface skin 39 is formed inside, and a mounted part 37 (solid region portion B) which is adjacent to the expanding region portion A, expands no cavity volume in molding, and is formed on a solid layer 43 having a high resin density without having the expansion layer 41. In the carrier plate 9, a thick-walled part 45 comprising the solid layer 43 is formed integrally on the barrier of the mounted part 37 with the expanding region portion A so as to thicken in a cavity volume expanding direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides an expansion region portion in which a skin layer having a high resin density is formed on the surface and an expansion layer having a large number of voids and having a resin density lower than that of the skin layer, and the expansion region portion It is related with the panel-shaped resin molded object comprised by the solid area | region part formed in the solid layer with a high resin density which does not have the said expansion | swelling layer adjacently, and its molding method.

In Patent Document 1, with a mold composed of a movable mold and a movable mold housed in a closed mold, a thermoplastic resin containing fibers is injected and filled into a cavity, and the fibers are contained in the cavity. In the process in which the thermoplastic resin is solidified, the skin is formed on the surface and has a large number of voids by retracting the movable mold in the movable mold in the cavity volume expansion direction to expand the thermoplastic resin containing fibers. A technique for molding a resin molded body in which an intumescent layer is formed is disclosed. In the molded resin molded body, a concave portion of a resin layer having a non-expandable or low expansion rate is formed in the thickness direction of the resin molded body to prevent local stress and twist.
Japanese Patent Laid-Open No. 11-156881 (page 3, FIG. 1)

  By the way, when attaching a part, for example, to the resin molded body in which the expansion layer is formed in the entire inner area as described above, it is rigid to make the part attachment portion a solid region portion formed in the solid layer without having the expansion layer. It is desirable from the viewpoint of enhancing. As a method, first, for example, a slide mold is disposed on a fixed mold of the mold so as to be able to advance and retreat in correspondence with a solid region portion forming position, and the tip mold surface of the slide mold is the same as the molding surface of the fixed mold. In such a state, the fiber-filled thermoplastic resin is injected and filled into the cavity. Next, when the skin layer is formed on the fiber-containing thermoplastic resin in the vicinity of the molding surface of the mold due to the solidification of the fiber-containing thermoplastic resin, the movable mold is retracted in the cavity volume expansion direction to make the fiber-containing thermoplastic The resin is expanded and the slide mold is advanced into the cavity by following the retreating operation in the cavity volume expansion direction of the movable mold so that the cavity volume at the corresponding position of the slide mold does not expand. As a result, it is considered to form a resin molding in which the skin layer is formed on the surface and the solid region formed in the solid layer without the expansion layer is adjacent to the expansion region in which the expansion layer is formed. It is done.

  However, since the slide mold is made of hard metal or hard resin, and the outer periphery of the molding surface is sharp and square, if the resin mold is molded as described above, the slide mold can be used even if the slide mold advances into the cavity. The fiber-containing thermoplastic resin in the solidification progress state of the part is not pushed by the slide mold, but the outer peripheral edge of the slide mold that is sharp and angular is cut into the fiber-containing thermoplastic resin in the solidification progress state around it, As a result, a crack occurs at the boundary between the solid region portion and the expanded region portion, and the rigidity of the molded resin molded body is lowered.

  The present invention has been made in view of such points, and the object of the present invention is to prevent cracks from occurring at the boundary between the solid region portion and the expanded region portion in the expanded resin molded body. is there.

  In order to achieve the above object, the present invention is characterized in that the rigidity strength of the boundary between the solid region portion and the expanded region portion is increased, and specifically, the following solution is taken.

  That is, according to the first aspect of the present invention, when the skin layer is formed on the fiber-containing thermoplastic resin in the vicinity of the molding surface of the mold due to the solidification of the fiber-containing thermoplastic resin injected and filled in the cavity of the mold. By expanding the cavity volume and expanding the fiber-containing thermoplastic resin, a skin layer having a high resin density is formed on the surface, and the resin layer has a large number of voids and has a lower resin density than the skin layer. An expansion region portion in which a layer is formed, and a solid region portion that is adjacent to the expansion region portion and formed in a solid layer having a high resin density without expanding the cavity volume at the time of molding. A panel-shaped resin molded body configured, and at the boundary between the solid region portion and the expanded region portion, a fiber-containing thermoplastic resin is placed in a cavity corresponding to the location. By increasing the cavity volume around the outer periphery in a state where the cavity volume is expanded more than the lid region side, the thick portion made of the solid layer is integrally formed so as to be thicker in the cavity volume expansion direction. It is characterized by.

  Invention of Claim 2 is a molding method of the resin molding of Claim 1, Comprising: The slide type | mold with which the chamfered part was formed in the front-end | tip outer periphery part corresponds to a solid area | region part formation location. Prepare a mold that can be moved forward and backward, and when the mold is closed, the resin filling amount of the cavity corresponding to the chamfered portion of the slide mold is larger than the tip molded surface excluding the chamfered portion. Filling the cavity with fiber-containing thermoplastic resin so that it increases in the expanding direction, and then the solidification of the fiber-containing thermoplastic resin produces a skin layer on the fiber-containing thermoplastic resin in the vicinity of the molding surface of the mold. At this point, the cavity volume around the outer periphery of the slide mold corresponding part is not enlarged, and the fiber-containing thermoplastic resin at the cavity part is expanded.

  According to the first aspect of the present invention, the skin layer is formed on the surface of the expansion region portion, and the expansion layer having a large number of voids is formed inside, whereby the weight of the resin molded body can be reduced. Further, in addition to the solid region portion being formed as a solid layer having a high resin density without an expanded layer, a thick portion made of a solid layer is formed at the boundary between the solid region portion and the expanded region portion. Thus, the solid region can be firmly strengthened in rigidity and particularly in compressive strength. Furthermore, the thick wall portion formed of the solid layer at the boundary between the solid region portion and the expansion region portion is formed by increasing the resin filling amount of the cavity corresponding to the location in the cavity volume expansion direction as compared with the solid region portion side. Therefore, when the cavity volume corresponding to the expansion region portion is expanded at the time of expansion molding, a part of the gel-like resin that is not yet solidified flows out into the enlarged cavity, and at this time, the gel-like resin Is a resin that is in a solidified state, and is much softer than hard metal or hard resin slide molds, so the gel-like resin acts as a cushion (buffer) and advances the output around the tip of the slide mold. Is absorbed. Therefore, a crack does not occur at the boundary between the solid region portion and the expanded region portion, and the rigidity strength of the molded resin molded body can be ensured.

  According to the second aspect of the present invention, a resin molding having an excellent strength and rigidity without a crack as described above with a simple mold structure without significantly modifying the mold structure by simply forming a chamfered portion on the slide mold. The body can be molded inexpensively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 is a sectional view of the side door 1 of the automobile. The side door 1 includes a metal door main body 7 including a door outer panel 3 and a door inner panel 5. The door inner panel 5 of the door main body 7 has a resin carrier plate (door) as a panel-shaped resin molded body. A module plate 9 is attached via a seal material 11, and a door trim 13 is attached to the door inner panel 5 so as to cover the carrier plate 9 from the vehicle interior side.

  The carrier plate 9 is formed of a fiber-containing thermoplastic resin, and includes a plate body 15 having an expansion region A and a solid region B, which will be described later, which are the main components of the carrier plate 9. As shown in FIG. 2, a seal groove portion 17 that accommodates the sealing material 11 is formed in the outer peripheral edge portion of the plate body 15 on the outer side surface side of the passenger compartment. Further, in the vicinity of the outer peripheral edge of the plate body 15 (inside the seal groove portion 17), a plurality of circular mounting portions 19 in a plan view are integrally projected adjacently over the entire circumference with a predetermined interval, A fastening through-hole 19 a is formed in each attachment portion 19 so as to penetrate the plate body 15. Then, the carrier plate 9 is overlaid on the door inner panel 5 so that the through holes 19a of the mounting portions 19 correspond to the plurality of bolt insertion holes 5b formed in the opening peripheral edge portion 5a of the door inner panel 5, Bolts 21 are inserted from the vehicle interior side into the through holes 19a and the bolt insertion holes 5b, and screwed into weld nuts 23 welded to the vehicle outer side surface of the door inner panel 5, whereby the carrier plate 9 is attached to the door inner panel 5. (See FIG. 3).

  Two cylindrical mounting seats 25 each having a circular shape in plan view are provided on the upper end edge and the lower end edge of the plate main body 15 on the outer side surface side of the plate body 15 so as to protrude integrally adjacent to each other at intervals in the vehicle width direction. A metal guide rail 27 for raising and lowering the glass is attached to the mounting seat 25 with bolts 29 and nuts 31 (see FIG. 2). At both ends of the guide rail 27, rollers 33 for guiding a window glass raising / lowering wire (not shown) are rotatably supported by a shaft 35.

  In the middle of FIG. 2 of the plate main body 15, a mounting portion 37 having a substantially triangular shape in plan view, which is the solid region portion B for mounting a motor for raising and lowering a window glass (not shown), is formed integrally adjacent to the plate body 15. A circular motor mounting hole 37a is formed in the portion 37 so as to pass through the plate body 15. Around the motor mounting hole 37a, three screw insertion through holes 37b are formed at the apex of the triangle. It is formed so as to penetrate the plate body 15 corresponding to the position.

  The expansion region portion A of the plate body 15 is formed so as to surround the solid region portion B (attachment portion 37), and is made of a fiber-containing thermoplastic resin R injected and filled into a cavity 53 of a molding die 47 described later. When the skin layer 39 is formed on the fiber-containing thermoplastic resin R in the vicinity of the molding surfaces 49b, 51c, and 55a of the molding die 47 (the stationary die 49, the slide die 51, and the movable die 55) due to the progress of solidification, the plate body By expanding the cavity volume corresponding to 15 and expanding the fiber-containing thermoplastic resin R, as shown in FIG. 1, a hard skin layer 39 having no voids and high resin density is formed on the surface, and a large number of And an expansion layer 41 having a resin density lower than that of the skin layer 39 is formed inside. In FIG. 3, the plate body 15 is shown as a single layer for convenience of drawing. On the other hand, as shown in FIGS. 1 and 5, the mounting portion 37 is formed in a solid layer 43 having a high resin density without expanding the cavity volume during molding and without having the expansion layer 41. In addition, at the boundary between the attachment portion 37 and the expansion region portion A, more fiber-containing thermoplastic resin R is added to the cavity corresponding to the location, which is a feature of the present invention, in the cavity volume expansion direction than the solid region portion B side. By expanding the cavity volume around the outer periphery in the filled state, the annular thick portion 45 having a substantially triangular shape in plan view, which is formed of the solid layer 43, is integrally formed so as to be thicker in the cavity volume increasing direction. A slit-like annular groove 46 is formed between the thick portion 45 and the expansion region portion A. Although not shown, the mounting portion 19 and the mounting seat 25 are also formed in the solid layer 43 having a high resin density without expanding the cavity volume at the time of molding, as in the mounting portion 37, without having the expansion layer 41. Yes.

  Next, the procedure for forming the carrier plate 9 will be described. Here, the mold structure around the mounting portion 37 will be described with reference to FIGS. 4 and 5. However, since the mounting portion 19 and the mounting seat 25 also have basically the same mold structure, the description thereof will be omitted. .

  First, as shown in FIG. 4, the mold 47 is closed. In the fixed die 49, a slide die 51 for forming the attachment portion 37 is accommodated and disposed in the accommodation hole 49a while being urged in the advancing direction by an extension operation of a hydraulic cylinder (not shown). In this state, the slide mold 51 is biased in the advancing direction by the extension operation of a hydraulic cylinder (not shown), but a large-diameter convex portion for forming a motor mounting hole 37a formed at the tip of the slide mold 51. The small-diameter convex portion 51b for forming 51a and the through-hole 37b advances into the cavity 53 and contacts the molding surface 55a of the movable die 55, and the advancement operation of the slide die 51 is restricted, and the molding surface of the slide die 51 51c is flush with the molding surface 49b of the fixed die 49, and the entire chamfered portion 51d formed by cutting out at a right angle to the outer peripheral edge of the slide die 51 is positioned below the molding surfaces 49b and 51c. It has been. The molding surface 51c of the slide mold 51 may protrude into the cavity 53 more than the molding surface 49b of the fixed mold 49 in the mold closed state. In this case, the chamfered portion 51d of the slide mold 51 is It is preferably formed so as to extend from the molding surface 49b of the fixed die 49 by a predetermined dimension in the backward direction of the slide die 51.

  Next, a thermoplastic resin R containing fibers such as glass fibers (for example, polypropylene resin containing fibers) is injected and filled into the cavity 53 of the mold 47 from an injection machine (not shown). FIG. 5 shows this injection filling state. In this state, the fiber-filled thermoplastic resin R has a larger resin filling amount in the cavity corresponding to the chamfered portion 51d of the slide mold 51 in the cavity volume expansion direction than the tip molding surface 51c excluding the chamfered portion 51d. .

  Thereafter, in the process in which the fiber-containing thermoplastic resin R injected and filled in the cavity 53 of the mold 47 is solidified, that is, as the fiber-filled thermoplastic resin R is solidified, the molding surfaces 49b, 51c, 55a of the mold 47 are formed. When the skin layer 39 is formed on the fiber-containing thermoplastic resin R in the vicinity, as shown in FIG. 5, the movable die 55 is retracted in the cavity volume expansion direction Y1 (die opening direction). In other words, the movable die 55 is slightly separated from the fixed die 49, and the cavity volume is increased, for example, twice or more. As a result, the slide mold 51 follows the backward movement of the movable mold 55 in the direction of the arrow Y2 and advances into the cavity 53. Therefore, the cavity volume at the corresponding position of the slide mold does not increase. At this stage, the fiber-containing thermoplastic resin R becomes a hard skin layer 39 without voids because the portions contacting the molding surfaces 49b, 51c, 55a of the molding die 47 are cooled early due to the influence of the mold temperature. To form a surface layer. On the other hand, the inner part of the fiber-containing thermoplastic resin R is hardly affected by the mold temperature and is in a gel state with high viscosity. Therefore, as the cavity volume increases, the fiber-containing thermoplastic resin R that has been compressed by the fixed mold 49 and the movable mold 55 is pulled by the molding surface 55a of the movable mold 55 and expands. At this time, the fibers in the fiber-containing thermoplastic resin R are also elastically restored with the compression reduced, and the thermoplastic resin R expands also by this elastic restoring force (spring back phenomenon).

  As a result, the plate body 15 is formed, in which the rigid skin layer 39 without voids is formed on the surface, and the expansion region portion A having the expansion layer 41 having a large number of voids (not shown) therein is formed. The In addition, the fiber-containing thermoplastic resin R in the cavity 53 corresponding to the mounting portion 37 follows the backward movement of the slide mold 51 in the direction of the arrow Y2 even when the movable mold 55 is retracted in the cavity volume expansion direction Y1. Therefore, the cavity space does not expand and therefore does not move without being pulled by the molding surface 55 a of the movable die 55, so that the attachment portion 37 is adjacent to the expansion region portion A and is solid solid layer 43. Is formed. A motor mounting hole 37a and a through hole 37b are formed in the mounting portion 37, and the thickness of the solid layer 43 is formed at the boundary between the mounting portion 37 (solid region portion B) and the expansion region portion A. The thick portion 45 is integrally formed to be thick in the cavity volume expansion direction Y1, and a slit-like annular groove 46 is formed between the thick portion 45 and the expansion region portion A. Similarly, the mounting portion 19 for mounting the carrier plate and the mounting seat 25 for mounting the guide rail that guides the window glass up and down are also formed in the solid solid layer 43.

  In this way, the plate body 15 excluding the solid region portion B, the attachment portion 19 and the attachment seat 25 has the skin layer 39 formed on the surface and the expansion layer 41 having a large number of voids inside. As compared with the case where the plate body 15 is composed only of the solid layer having no expansion layer 41 and has the same thickness as the plate body 15 of the present embodiment, the weight can be reduced.

  Further, since the mounting portions 19 and 37 and the mounting seat 25 are formed in the solid layer 43 having a high resin density without the expansion layer 41, the rigidity of these members, particularly the compression strength, should be firmly strengthened. Can do. In addition, since the thick portion 45 made of the solid layer 43 is formed at the boundary between the mounting portion 37 and the expansion region portion A, the rigidity strength, particularly compressive strength, of the mounting portion 37 can be further improved.

  Further, from the state in which the tip molding surface 51c of the slide mold 51 and the molding surface 49b of the fixed mold 49 are flush with each other when the thermoplastic resin R containing fibers is injected and filled, the slide mold 51 is in the cavity 53 during expansion molding. In this case, since the chamfered portion 51d is formed in the slide mold 51, the vicinity of the tip of the slide mold 51 (slide mold forming surface 51c) is closer than that in which the chamfered portion 51d is not formed. Thus, when the slide mold 51 advances during expansion molding, a part of the gel-like resin that is not yet solidified flows out into the enlarged cavity 53. At this time, the gel resin is a resin in a solidified state, and is much softer than the hard metal or hard resin slide mold, so the gel resin acts as a cushion (buffer) and slide type The advance output around the tip of 51 is absorbed and relaxed. Therefore, no crack is generated at the boundary between the attachment portion 37 and the expansion region portion A, and the rigidity strength of the molded carrier plate 9 can be ensured.

  Furthermore, by simply forming the chamfered portion 51d on the slide mold 51, the carrier plate 9 having a simple mold structure without cracks as described above and having excellent strength and rigidity can be formed at low cost without significantly modifying the mold structure. can do.

  In the above-described embodiment, the chamfered portion 51d of the slide mold 51 is configured to be cut out at a right angle. However, the chamfered portion 51d is formed into an inclined surface that is diagonally cut out linearly or is convex. You may comprise a curved surface, a concave curved surface, etc. The slide mold 51 and the mounting portions 19 and 37 and the mounting seat 25 formed thereby are not limited to the shapes described in the embodiment, and the mounting portion 19 and the mounting seat 25 have an elliptical cross section other than a circular shape. The mounting portion 37 for mounting the window glass raising / lowering motor is not limited to a substantially triangular shape in plan view.

  Furthermore, in the above-described embodiment, if the foamed thermoplastic resin R contains a foam material, the retraction amount of the movable mold 55, that is, the expansion ratio is increased, and the thickness (plate thickness) of the plate body 15 in the movable mold retraction direction is increased. ) Is thick, even if the expansion amount of the fiber-containing thermoplastic resin R is insufficient, the foaming force (expansion pressure) of the foam material complements it, and it is preferable. In these cases, examples of the foam material include a chemical foam material that generates a gas by a chemical reaction, and a physical foam material that uses an inert gas such as carbon dioxide gas and nitrogen gas.

  In addition, in the above embodiment, during expansion molding, the slide mold 51 is provided on the fixed mold 49 side so as to follow the retreating operation of the movable mold 55 and advance into the cavity 53, whereby the mounting seats 19 and 37 and the mounting Although the seat 25 is formed in the solid layer 43, the slide die 51 is provided on the movable die 55 side, and only the movable die 55 is retracted in the expansion molding process so that the slide die 51 is not retracted. 37 and the mounting seat 25 may be formed in the solid layer 43.

  Furthermore, in the above embodiment, the case where the resin molded body is the carrier plate 9 of the side door of the automobile is shown. However, other automobile panels such as instrument panels, door trims, trunk boards, etc. It can also be applied to residential panels.

  The present invention provides an expansion region portion in which a skin layer having a high resin density is formed on the surface and an expansion layer having a large number of voids and having a resin density lower than that of the skin layer, and the expansion region portion It is useful for a panel-shaped resin molded body formed of a solid region portion formed in a solid layer having a high resin density without having the above-mentioned expansion layer.

It is sectional drawing in the II line | wire of FIG. It is the front view which looked at the carrier plate from the vehicle compartment outer side. It is sectional drawing of the side door of the motor vehicle in the III-III line of FIG. It is an injection molding process figure of the II line cross-section corresponding | compatible part of FIG. 2 which shows the state which injected and filled the thermoplastic resin containing a fiber in the cavity of a shaping | molding die. FIG. 5 is a view corresponding to FIG. 4 illustrating an expansion molding process in a state where the movable mold is slightly retracted in the direction in which the cavity volume is increased.

Explanation of symbols

9 Carrier plate (resin molding)
15 Plate body 37 Attaching part 39 Skin layer 41 Expansion layer 43 Solid layer 45 Thick part 47 Molding die 49 Fixed mold 49b Fixed mold molding surface 51 Slide mold 51c Slide mold molding surface 53 Cavity 55 Movable mold 55a Movable mold molding Surface A Expansion area B Solid area R Fiber-filled thermoplastic resin

Claims (2)

When the skin layer is formed on the fiber-filled thermoplastic resin in the vicinity of the molding surface of the mold due to the solidification of the fiber-filled thermoplastic resin injected and filled into the mold cavity, the cavity volume is expanded to contain the fiber. By inflating the thermoplastic resin, a skin layer having a high resin density is formed on the surface, and an expansion region portion in which an expansion layer having a large number of voids and having a resin density lower than that of the skin layer is formed. ,
A panel-shaped resin molded body formed of a solid region portion formed in a solid layer having a high resin density without having the expansion layer and without expanding the cavity volume at the time of molding adjacent to the expansion region portion. ,
At the boundary between the solid region portion and the expansion region portion, the cavity volume around the outer periphery is set in a state in which the cavity corresponding to the portion is filled with more fiber-filled thermoplastic resin in the cavity volume expansion direction than the solid region portion side. A resin molded body, wherein the resin molded body is integrally formed so that the thick-walled portion made of the solid layer is thickened in the cavity volume expansion direction by being expanded. A method for molding a resin molded body according to claim 1,
Prepare a mold that can be moved back and forth so that the slide mold with the chamfered part formed at the outer periphery of the tip corresponds to the solid area part forming position,
Thermoplastic resin containing fibers so that the resin filling amount of the cavity corresponding to the chamfered portion of the slide die is larger in the cavity volume expansion direction than the tip molding surface excluding the chamfered portion when the mold is closed. In the cavity,
Next, when the skin layer is formed on the fiber-containing thermoplastic resin in the vicinity of the molding surface of the mold due to the solidification of the fiber-containing thermoplastic resin, the outer circumference of the slide mold-corresponding portion is increased without increasing the cavity volume. A method for molding a resin molded body, wherein the cavity volume of the resin is expanded to expand the fiber-containing thermoplastic resin at the cavity portion.

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