JP6587855B2 - Injection molding method and mold - Google Patents

Description

  The present invention relates to a method and a mold for injection-molding a two-color molded product in which a secondary molded product composed of a second resin is laminated on a peripheral portion of a primary molded product composed of a first resin. It is about.

  Conventionally, as one method of injection molding, a two-color molded product in which a secondary molded product composed of a second resin is arranged around a primary molded product composed of a first resin is injection molded. The method is known.

  In “Patent Document 1”, as a mold for performing such injection molding, a primary core side mold and a secondary core side mold, which are arranged at positions apart from each other, and these primary core side molds are disclosed. A rotating member arranged to be rotatable around an axis passing between the mold and the secondary core side mold, and the primary core side mold and the secondary core side mold and the mold closing / opening with respect to the rotating member. A configuration with a pair of cavity-side molds fixed in a possible state is described.

  The injection molding of a two-color molded product using the mold described in “Patent Document 1” is performed as follows.

  That is, as shown in FIG. 9A, the first resin material is injected into the first cavity s1 formed by closing the first cavity side mold 5 and the primary core side mold 6. Then, the primary molded product 1 is molded, and then the molds 5 and 6 are opened so that the primary molded product 1 is held by the first cavity-side mold 5, and the rotating member is rotated around the axis. The first cavity side mold 5 holding the primary molded product 1 and the secondary core side mold 7 are rotated to face each other, and as shown in FIG. The second resin material is injected into the second cavity s2 formed by closing the mold, and the secondary molded product is molded on the peripheral edge of the primary molded product 1 to obtain a two-color molded product.

  In particular, the first cavity-side mold 5 has a retracting mechanism configured to allow the plunger 3a to protrude into the first cavity s1 from a direction intersecting with the mold closing / opening direction (left-right direction in FIG. 9). 3 is arranged, the primary molded product 1 is molded in a form in which the tip of the plunger 3a protrudes into the first cavity s1, and then the rotating member is rotated until the two-color molded product is taken out. The plunger 3a is retracted between them.

  For this reason, the primary molded product 1 molded by the first cavity s1 is supported by the plunger 3a protruding from the molding surface 5a of the first cavity-side mold 5 when the mold is opened, for example. Is supported by the tip of the plunger 3a protruding in a direction perpendicular to the direction in which the primary molded product 1 deviates from the first cavity side mold 5 (the right direction in FIG. 9A). The primary molded product 1 is unlikely to deviate from the first cavity side mold 5.

  For example, when the molds 5 and 6 are opened after the primary molded product 1 is molded, the primary molded product 1 is not the primary core side mold 6 but the first cavity side mold 5. Holds securely. Thereby, the transition to the process of molding the secondary molded product becomes smooth.

JP 2014-168936 A

  However, in the method according to “Patent Document 1”, the concave portion 1b (see FIG. 9B) formed when the plunger 3a is retracted remains as a trace on the peripheral portion of the two-color molded product, and the appearance is improved. descend. In particular, when a two-color molded product is used as the front cover of an automotive headlamp, the front cover is generally subjected to a weather hard, durable, and wear resistant surface hard coat treatment. The treatment liquid accumulates in the recess 1b and looks white, and the appearance is further deteriorated.

  Further, by the method according to “Patent Document 1”, a two-color molding in which a secondary molded product made of the second resin is laminated and arranged on the peripheral portion of the primary molded product 1 made of the first resin. When the product was injection-molded, a so-called “color cast” was generated in which a part of the resin constituting the secondary molded product wraps around the peripheral surface of the primary molded product 1.

  Then, when the inventor considered the cause of this “color cast”, the following was found.

  As shown in FIG. 9 (a), the first resin material is injected into a first cavity s1 formed by closing the cavity side mold 5 and the secondary core side mold 6 to form the primary resin. After the molded product 1 is molded, the mold is opened, and the cavity-side mold 5 and the secondary core-side mold 7 that hold the primary molded product 1 are closed as shown in FIG. 9B. By injecting the second resin material into the second cavity s2, the secondary molded product is laminated and formed on the peripheral edge of the primary molded product 1, but the primary molded product 1 is a cavity side mold. After being molded by the primary core side mold 6 and the primary core side mold 6, the mold shrinks in the process of cooling by contact with the atmosphere by opening the mold. That is, due to the heat shrinking action of the resin material constituting the primary molded product 1, the peripheral edge 1 a shrinks in the direction of narrowing the surface area along the molding surface 5 a of the mold 5 and peels off from the molding surface 5 a. When the second resin material is injected into the second cavity s2 in a state where a gap s is generated between the peripheral edge 1a and the molding surface 5a of the mold 5, a part of the second resin material is in a flange shape. Secondary molding is performed in a form that enters the gap s between the peripheral edge 1 a and the molding surface 5 a of the mold 5. As a result, color fog occurs at the peripheral edge of the molded two-color molded product.

  The present invention has been made in view of such circumstances, and the peripheral portion of the two-color molded product is not left as a concave portion, and the peripheral portion of the two-color molded product does not remain as a recess. An object of the present invention is to provide an injection molding method and a mold in which no color cast is generated.

  The present invention is intended to achieve the above object by using a predetermined in / out mechanism.

That is, the injection molding method according to the present invention is:
A method for injection molding a two-color molded product in which a secondary molded product is laminated and disposed on a peripheral portion of a primary molded product,
Injecting the first resin material into the first cavity formed by closing the cavity side mold and the primary core side mold to mold the primary molded product,
Next, a second resin material is injected into a second cavity formed by closing the cavity side mold and the secondary core side mold for holding the primary molded product, and the primary resin is injected. When laminating the secondary molded product on the periphery of the molded product,
In the cavity-side mold, an intrusion mechanism configured to project at least one protrusion at a portion corresponding to a peripheral edge of the primary molded product of the first cavity is arranged,
The primary molded product is molded in a form in which the protrusion protrudes across a portion corresponding to the peripheral edge of the primary molded product of the first cavity,
Then, when the second resin material is injected into the second cavity to laminate the secondary molded product, the protrusion is retreated to the molding surface of the cavity side mold. To do.

In addition, the mold according to the present invention is
A mold for injection molding a two-color molded product in which a secondary molded product is laminated and disposed on the peripheral edge of the primary molded product,
A primary molding die which is composed of a cavity side mold and a primary core side mold, and injects a first resin material into a first cavity formed by closing the mold to mold the primary molded product. Type,
A second cavity formed by closing the cavity side mold and the secondary core side mold, which is configured by the cavity side mold and the secondary core side mold and holds the primary molded product. A second molding material for injecting a second resin material and laminating and molding the secondary molded product on the periphery of the primary molded product;
A protrusion / displacement mechanism that is arranged on the cavity side mold and is configured so that a protrusion that can move forward and backward protrudes into a portion of the first cavity corresponding to the peripheral portion of the primary molded product and traverses the portion. It is characterized by comprising.

  The specific configuration of the “protruding mechanism” is not particularly limited, and for example, a hydraulic cylinder mechanism, an air cylinder mechanism, or the like that moves the plunger corresponding to the protruding portion back and forth can be employed.

  (Operation) The primary molded product molded in the first cavity tries to stick to the primary core side mold by heat shrinkage when the mold is opened, but it tries to stick to the primary core side mold. Since the resin constituting the peripheral portion of the primary molded product is heat-shrinked and has a greater force to hold onto the protruding portion of the intruding mechanism than the force to be held, it is held in the cavity side mold. Therefore, in the mold opening after molding the primary molded product, the primary molded product is securely held in the cavity side mold, so the cavity side mold and the secondary core side mold that hold the primary molded product are retained. The transition to the next process of closing the mold becomes smooth.

  Further, the primary molded product molded in the first cavity comes into contact with the atmosphere by opening the mold, so that the thermal contraction of the resin further proceeds and tends to shrink in the direction in which the entire surface area becomes smaller. For this reason, the cavity side mold until the second resin material is injected into the second cavity formed by closing the cavity side mold for holding the primary molded product and the secondary core side mold. The entire primary molded product that is in close contact with the molding surface is contracted and deformed in the direction in which the surface area is reduced, and the peripheral portion of the primary molded product in which displacement due to thermal contraction appears is peeled off from the molding surface of the cavity side mold. There is a possibility that a gap that causes “color cast” occurs between the molding surface and the peripheral portion of the primary molded product.

  However, in the present invention, since the protruding portion of the protruding and protruding mechanism that protrudes from the molding surface of the cavity side mold crosses the peripheral edge of the primary molded product where displacement due to thermal contraction appears greatly, the entire primary molded product Deformation due to thermal shrinkage in the direction in which the surface area of the resin shrinks is effectively suppressed. In other words, the protrusion of the protrusion / projection mechanism that protrudes from the molding surface of the cavity-side mold and passes through the peripheral edge of the primary molded product suppresses deformation due to thermal contraction in the direction in which the surface area of the entire primary molded product is reduced. .

  In particular, since the displacement of the peripheral portion of the primary molded product, where deformation due to heat shrinkage becomes significant, is reliably suppressed, the second resin material is injected into the second cavity, and the secondary molded product is laminated. Until just before the start, the primary molded product is held in a form in which the whole including its peripheral edge is in close contact with the molding surface of the cavity side mold.

  Therefore, a so-called “color cast” in which a part of the second resin material injected into the second cavity wraps around between the peripheral edge of the primary molded product and the molding surface of the cavity side mold does not occur. .

  In addition, when the secondary molded product is laminated and molded in a form in which the protruding portion of the protruding / extracting mechanism is extracted from the peripheral portion of the primary molded product and retracted to the molding surface of the cavity side mold, the leaving trace of the protruding portion of the protruding / extracting mechanism Is formed in the peripheral edge of the primary molded product, and a part of the second resin material injected into the second cavity is filled into the through hole and molded. That is, the through-hole formed in the peripheral portion of the primary molded product, which is a leaving trace of the protruding portion, has a convex on the side of the secondary molded product having an end surface that is formed with the protruding portion tip surface of the protrusion / departure mechanism as the molding surface. The parts are engaged and integrated.

  In addition, as an injection molding method according to the present invention, it is desirable to inject the second resin material into the second cavity after confirming the withdrawal of the protrusion by a sensor provided in the retracting mechanism. For example, it is conceivable that the side valve gate communicated with the second cavity is opened when a predetermined amount of protrusion of the protrusion is detected by a limit switch provided in the retracting mechanism.

  (Operation) When the mold is closed and the secondary molded product is laminated, if the timing for retracting the protruding portion of the retracting mechanism is delayed, the second resin material filled in the second cavity The filling pressure changes (decreases) during the process, and stable injection molding cannot be performed. In addition, the protrusion with the molten resin attached to the tip is withdrawn, which may hinder smooth driving of the protrusion mechanism (smooth protrusion and protrusion operation of the protrusion).

  However, in the present invention, the second resin material is injected into the second cavity after confirming that the protrusion of the protrusion / retraction mechanism has retreated to the molding surface of the cavity side mold by the sensor provided in the protrusion / retraction mechanism. Therefore, the filling pressure of the second resin material does not change (decrease) in the middle, and stable injection molding can be performed. In addition, the protrusion with the molten resin attached to the tip does not retreat, and the smooth drive of the protrusion / retraction mechanism (smooth protrusion / distraction operation of the protrusion) is not hindered.

In addition, as a mold according to the present invention,
It is desirable that the tip of the protruding portion of the protrusion / displacement mechanism disposed in the cavity side mold is formed in a shape that follows the molding surface of the cavity side mold that forms the first cavity.

Moreover, the two-color molded product according to the present invention is a two-color molded product in which the secondary molded product is laminated and arranged on the peripheral edge of the primary molded product molded by the method according to the present invention,
The peripheral part of the primary molded product is provided with at least one through hole formed when the protruding portion of the retracting mechanism is retracted, and the through hole is stacked and arranged on the primary molded product. The convex part of the secondary molded product is engaged and integrated.

  (Operation) Since the secondary molded product is laminated and formed with the protruding portion of the protruding and retracting mechanism retracted to the molding surface of the cavity side mold, the protruding portion of the protruding and retracting mechanism is retracted (from the peripheral portion of the primary molded product). At the time of extraction, a through hole which is a leaving trace of the protrusion is formed in the peripheral portion of the primary molded product, and the second resin material constituting the secondary molded product is integrally filled in the through hole. It has become. In other words, the convex part on the secondary molded product side having the end surface formed with the tip end surface of the protruding portion of the intrusion mechanism as the molding surface is engaged and integrated.

  And since the front end surface of the protrusion part of the intrusion mechanism is formed in a shape that follows the molding surface of the cavity side mold that forms the first cavity, the molding surface of the cavity side mold that forms the first cavity The peripheral region of the through hole of the molded primary molded product and the end surface of the convex part on the secondary molded product side that is molded and integrated in the through hole formed by the tip surface of the protruding portion of the protrusion / departure mechanism, The continuous surface of the peripheral part of a two-color molded product is comprised.

  As shown in the above configuration, according to the present invention, when the secondary molded product is laminated and formed on the peripheral portion of the primary molded product, the protruding portion of the retracting mechanism is retracted to the molding surface of the cavity side mold. It is possible to provide a two-color molded product in which the leaving trace of the protruding portion does not remain as a concave portion at the peripheral portion and the color fog does not occur at the peripheral portion.

It is a sectional side view which shows the metal mold | die used for the injection molding method which concerns on one Embodiment of this invention. It is a sectional side view which shows the two-color molded product shape | molded by the said injection molding method. (A), (b) is process explanatory drawing (the 1) of the said injection molding method. (C), (d) is process explanatory drawing (the 2) of the said injection molding method. (E), (f) is process explanatory drawing (the 3) of the said injection molding method. (G), (h) is process explanatory drawing (the 4) of the said injection molding method. (B), (e), (f) is the principal part expanded sectional view of FIG.3 (b), FIG.5 (e), FIG.5 (f). It is a figure similar to FIG.6 (g) which shows the modification of the said embodiment. It is sectional drawing explaining the problem at the time of carrying out the injection molding of the two-color molded product by which the secondary molded product is laminated | stacked and arrange | positioned by the method which concerns on a prior patent document at the peripheral part of a primary molded product, (a) is 1 The process of shape | molding a secondary molded product is shown, (b) shows the process of carrying out lamination molding of the secondary molded product.

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

  FIG. 1 is a side sectional view showing a mold 50 used in an injection molding method according to an embodiment of the present invention. FIG. 2 is a side sectional view showing the two-color molded product 10 that is injection-molded by the injection molding method according to the present embodiment.

  First, the configuration of the two-color molded product 10 will be described.

  As shown in FIG. 2, the two-color molded article 10 is a container-shaped translucent cover that is assembled to a front opening of a lamp body of a vehicle lamp such as a headlamp, and includes a front surface portion 10A and the front surface portion 10A. And a peripheral surface portion 10 </ b> B extending rearward from the outer peripheral edge. The peripheral surface portion 10B is formed with a flange portion 10Ba having a predetermined width extending from the rear end position toward the outer peripheral side and an annular protrusion portion 10Bb which is a seal leg protruding rearward from the rear surface.

  The two-color molded product 10 has a configuration in which a primary molded product 12 and a secondary molded product 14 are stacked and arranged from the peripheral surface portion 10B to the back surface side of the flange portion 10Ba. That is, the secondary molded product 14 is superposed on the back surface side of the peripheral surface portion 12b of the primary molded product 12 from the middle in the front-rear direction to the flange portion 12c. At that time, the primary molded product 12 is constituted by a transparent first resin member, and the secondary molded product 14 is constituted by an opaque (specifically, black) second resin member.

  In addition, a plurality of through holes 12d are formed in the circumferential direction in the flange portion 12c formed in the peripheral edge portion of the primary molded product 12, and secondary molding disposed on the back surface side in each through hole 12d. The convex portion 14a of the product 14 is engaged and integrated.

  Next, the configuration of the mold 50 will be described. As shown in FIG. 1, the mold 50 is configured as a so-called opposed type two-color molding mold.

  That is, the mold 50 includes a primary core side mold 52 and a secondary core side mold 54 that are disposed facing each other on the X axis extending in the horizontal direction, and the primary core side mold 52 and Between the secondary core-side molds 54, the rotating member 56 disposed so as to be rotatable around the Y axis extending perpendicularly to the X axis and fixed to the rotating member 56 in a back-to-back state with respect to the Y axis. A pair of cavity side molds 58A and 58B having the same shape, a movable plate 62 for supporting the primary core side mold 52, and a fixed plate 64 for supporting the secondary core side mold 54 are provided.

  At this time, the rotating member 56 is configured to be movable in the X axis direction with respect to the fixed platen 64, and the movable platen 62 is configured to be movable in the X axis direction with respect to the rotating member 56. In FIG. 1, the direction of these relative movements is indicated by arrows.

  In the mold 50, the movable plate 62 supports the first cavity C1 formed between the primary core side mold 52 and the first cavity side mold 58A that are in contact with each other when the mold is closed. The transparent first resin material supplied from the heating cylinder 66 is injected, and the primary molded product 12 is placed between the secondary core side mold 54 and the second cavity side mold 58B that are in contact with each other by closing the mold. The black second resin material supplied from the heating cylinder 68 supported by the fixed platen 64 is injected into the second space C2 formed therethrough.

  That is, the first cavity side mold 58 </ b> A constitutes a primary molding mold for molding the primary molded product 12 in cooperation with the primary core side mold 52 and is integrally 180 with the rotating member 56. The secondary molding die that molds the secondary molded product 14 is configured in cooperation with the secondary core side die 54 by rotating the secondary molding. On the other hand, the first cavity-side mold 58A and the second cavity-side mold 58B back to back cooperate with the primary core-side mold 52 via the rotating member 56 to mold the primary molded product 12. The secondary molding die that forms the secondary molded product 14 in cooperation with the secondary core side die 54 by constituting a primary molding die and rotating 180 degrees integrally with the rotating member 56. Configure the mold.

  In this manner, the primary molded product 12 is molded by the primary molding die on the left side of FIG. 1, and at the same time, the secondary molded product 14 is stacked by the secondary molding die on the right side of FIG. Molding (molding of the two-color molded product 10) is performed.

  In addition, hydraulic cylinders 70 each having a plunger 72 that is a retractable mechanism and that can move forward and backward are disposed at a plurality of locations on each cavity-side mold 58A, 58B. At this time, as shown in FIG. 7 (b), the plurality of hydraulic cylinders 70 have their plungers 72 set to 1 on the molding surfaces 58a and 58b of the respective cavity side molds 58A and 58B forming the first cavity C1. It arrange | positions at predetermined intervals in the circumferential direction of the molding surfaces 58a and 58b so that it may face the area | region corresponding to the flange part 12c of the next molded product 12. FIG. Each of these hydraulic cylinders 70 is configured such that its plunger 72 can protrude into the first cavity C1 from a direction parallel to the X axis (mold closing / mold opening direction).

  In addition, injection molding of the primary molded product 12 using the cavity side mold 58A, injection molding of the secondary molded product 14 (molding of the two-color molded product 10), and a primary molded product using the cavity side mold 58B. Since the injection molding 12 and the injection molding of the secondary molded product 14 (molding of the two-color molded product 10) are the same, mainly the injection molding and secondary molding of the primary molded product 12 using the cavity side mold 58A. The injection molding of the product 14 (molding of the two-color molded product 10) will be described. The injection molding of the primary molded product 12 using the cavity side mold 58B and the injection molding of the secondary molded product 14 (of the two-color molded product 10). The description of (molding) is omitted.

  Next, the injection molding method according to this embodiment will be described. 3 to 6 are process diagrams showing this injection molding method.

  First, as shown in FIG. 3A, the primary core side mold 52 and the secondary core side mold 54 and the pair of cavity side molds 58A and 58B are closed. At that time, the plunger 72 of each hydraulic cylinder 70 arranged in the cavity side mold 58A constituting the primary molding die is moved to a portion corresponding to the flange portion 12c of the primary molded product 12 in the first cavity C1. It protrudes into the first cavity C1 so as to penetrate the transverse direction. On the other hand, the plunger 72 of each hydraulic cylinder 70 arranged in the cavity side mold 58B constituting the secondary molding mold is set in a state of being retracted from the cavity between the molds 58B and 54. In this state, as shown in FIG. 3B, the transparent resin material supplied from the heating cylinder 66 is injected into the first cavity C1, and the primary molded product 12 is molded.

  Next, as shown in FIG. 4C, the primary core side mold 52 and the secondary core side mold 54 and the pair of cavity side molds 58A and 58B are opened. At this time, the primary molded product 12 tries to stick to the primary core side mold 52 by the shrinking action of the resin constituting the primary molded product 12, but the flange portion 12 c of the primary molded product 12 Since the plunger 72 of the hydraulic cylinder 70 is engaged through from the direction parallel to the mold closing / opening direction, when the molds 52, 58A are opened, the primary molded product 12 is moved to the cavity side mold 58A. The primary core side mold 52 is detached while being held. That is, the resin constituting the flange portion 12c of the primary molded product 12 is thermally contracted more than the force of the resin constituting the primary molded product 12 being heat-shrinked and sticking to the primary core side mold 52. Since the force hugging the plunger 72 is greater, the primary molded product 12 is held by the cavity side mold 58A when the mold is opened.

  In this state, as shown in FIG. 4D, the rotating member 56 is rotated 180 ° around the Y axis. At this time, centrifugal force acts on the primary molded product 12 held in the cavity side mold 58A, but since the plunger 72 is engaged with the flange portion 12c of the primary molded product 12, The state of being held by the cavity side mold 58A is maintained. That is, since the resin constituting the flange portion 12c of the primary molded product 12 is heat-shrinked to hold the plunger 72 more than the centrifugal force acting on the primary molded product 12, the rotating member 56 is moved in the Y axis. When rotating around 180 °, the primary molded product 12 is held by the cavity side mold 58A without dropping off.

Next, as shown in FIG. 5E, the primary core side mold 52 and the secondary core side mold 54 and the pair of cavity side molds 58B and 58A are closed. In this state, the hydraulic cylinder 70 disposed in the cavity side mold 58A is driven to retract the plunger 72 to the position of the molding surface 58a (see FIGS. 7E and 7F) and FIG. ), The black resin material supplied from the heating cylinder 68 is injected into the second cavity C2. Specifically, when a predetermined amount of the plunger 72 has been detected by the limit switch 74 incorporated in the hydraulic cylinder 70, the black resin material supplied from the heating cylinder 68 via the side valve gate 80 is second. The secondary molded product 14 is molded by being injected into the cavity C2 (see FIG. 7F). Thereby, the two-color molded product 10 in which the primary molded product 12 and the secondary molded product 14 are laminated and integrated is completed.

  Further, as shown in FIGS. 3A and 3B, the primary molded product 12 molded in the first cavity C1 is exposed to the atmosphere by opening the mold (see FIG. 4C). The heat shrinks further, and the whole surface area tends to shrink in the direction of shrinking. For this reason, as shown in FIGS. 5E and 5F, the second cavity C2 formed by closing the cavity side mold 58A for holding the primary molded product 12 and the secondary core side mold 54 is used. Before the second resin material is injected, the entire primary molded product 12 that is in close contact with the molding surface 58a of the cavity side mold 58A is contracted and deformed in the direction of reducing its surface area, and is displaced by thermal contraction. The flange portion 12c of the primary molded product 12 in which a large amount of toner appears is peeled off from the molding surface 58a of the cavity-side mold 58A, and there is a possibility that a gap that causes “color cast” occurs between the molding surface 58a and the flange portion 12c. is there.

  However, in this embodiment, as shown in an enlarged view in FIG. 7 (e), the plunger 72 protruding from the molding surface 58a of the cavity side mold 58A has a flange of the primary molded product 12 in which displacement due to thermal contraction appears greatly. Since it crosses and penetrates the part 12c, the deformation | transformation by the heat shrink in the direction which reduces the area of the whole primary molded product 12 is suppressed effectively. That is, the plunger 72 of the hydraulic cylinder 70 that protrudes from the molding surface 58a of the cavity side mold 58A and passes through the flange portion 12c of the primary molded product 12 heats in the direction in which the area of the entire primary molded product 12 is reduced. Suppresses deformation due to shrinkage.

  In particular, since the second resin material is injected into the second cavity C2 at the same time when the retract of the plunger 72 of the hydraulic cylinder 70 is detected by the limit switch 74, the second resin material is injected into the second cavity C2. The entire portion including the flange portion 12c of the primary molded product 12 is held in a form in close contact with the molding surface 58a of the cavity-side mold 58A until immediately before the secondary molding 14 is started.

  For this reason, a part of the second resin material injected into the second cavity C2 wraps around between the flange portion 12c of the primary molded product 12 and the molding surface 58a of the cavity side mold 58A. "Cover" does not occur.

  Further, when the secondary molded product 14 is injection-molded in a form in which the plunger 72 of the hydraulic cylinder 70 is retracted, a through-hole 12d that is a trace when the plunger 72 is extracted from the flange portion 12c, that is, a retracted trace of the plunger 72 is formed. Although formed in the flange portion 12c of the primary molded product 12, as shown in FIG. 7 (f), a part of the second resin material injected into the second cavity C2 is filled in the through hole 12d. Are molded and integrated. Therefore, the convex part 14a by the side of the secondary molded product 14 engages with the through-hole 12d, and the end surface 1b of the black convex part 14a is exposed to the through-hole 12d.

  Further, as shown in FIG. 7E, the distal end surface 72a of the plunger 72 of the hydraulic cylinder 70 is formed in a shape that follows the molding surface 58a of the cavity-side mold 58A that forms the first cavity C1, As shown in FIG. 7F, the secondary molded product 14 is injection-molded in a form in which the plunger 72 is retracted to a position where the distal end surface 72a of the plunger 72 coincides with the molding surface 58a of the mold 58A.

  Therefore, as shown in FIG. 2, the through hole 12d peripheral region 12d1 of the primary molded product 12 formed by the molding surface 58a of the cavity-side mold 58A that forms the first cavity C1, and the distal end surface of the plunger 72 The end surface 14b of the convex portion 14a on the side of the secondary molded product 14 formed by engagement with the through-hole 12d is formed by the flange portion 10Ba of the two-color molded product 10 (the flange portion of the primary molded product 12). 12c) constitute the continuous front.

  Finally, as shown in FIG. 6G, the primary core side mold 52 and the secondary core side mold 54 and the pair of cavity side molds 58B and 58A are opened. At this time, since the plunger 72 is not engaged with the primary molded product 12, the two-color molded product 10 is attached to the secondary core side mold 54 when the mold is opened. In this state, the two-color molded product 10 is taken out as shown in FIG. This take-out is performed by extruding the two-color molded product 10 attached to the secondary core side mold 54 with a push pin (not shown) and holding it with a take-out machine (not shown).

  In the front side of the flange portion 10Ba of the two-color molded product 10 thus molded (the flange portion 12c of the transparent primary molded product 12), as shown in FIG. A hole 12d is formed, and the convex portion 14a of the black secondary molded product 14 laminated on the back surface side is engaged and integrated with the through-hole 12d, and the end surface 14b of the convex portion 14a is connected to the flange portion 10Ba (flange). It is formed flush with the front surface of the part 12c).

  The two-color molding region including the flange portion 10Ba in which the primary molded product 12 and the secondary molded product 14 are arranged in a stacked manner passes through the transparent primary molded product 12 on the front side and the black of the secondary molded product 14 on the back side. Since the two-color molding region including the flange portion 10Ba looks black, the end surface 14b of the black convex portion 14a exposed to the flange portion 10Ba (flange portion 12c) cannot be recognized at all. Excellent appearance.

  Further, in order to use the two-color molded product 10 as a front cover of an automobile headlamp, even if the front cover 10 is subjected to a weather hard, durable and wear resistant surface hard coat treatment, the front surface of the flange portion 10Ba is provided. Since the end surface 14b of the convex portion 14a of the exposed secondary molded article 14 is formed flush with the front surface of the flange portion 10Ba, the applied hard coat treatment liquid is accumulated in the concave portion and looks white. There are no defects.

  Further, in the present embodiment, the two-color molded product 10 to be subjected to injection molding is a translucent cover for a vehicular lamp, and the primary molded product 12 is formed of a transparent resin member and the secondary molded product. Since the product 14 is made of an opaque resin member, the primary molded product 12 is relatively large and heavy. For this reason, the centrifugal force acting on the primary molded product 12 when the rotating member 56 rotates is increased, and the primary molded product 12 is easily detached from the cavity-side mold 58A. Therefore, it is particularly effective to adopt the configuration of this embodiment.

  In the above embodiment, when the withdrawal of the plunger 72 is detected by the limit switch 74 built in the hydraulic cylinder 70, the black resin material is injected into the second cavity C2 via the side valve gate 80. It is configured as follows. Therefore, before the molding of the secondary molded product 14 is started, the plunger 72 is reliably pulled out from the flange portion 12a of the primary molded product 12 and then retreated.

  That is, when the mold is closed and the secondary molded product 14 is laminated and the timing for retracting the plunger 72 of the hydraulic cylinder 70 is delayed, the filling pressure of the second resin material changes (decreases) in the middle. However, there is a possibility that smooth injection of the hydraulic cylinder 70 (smooth projecting and retracting operation of the plunger 72) may be hindered by the fact that the stable injection molding cannot be performed or the plunger 72 with the molten resin attached to the tip is withdrawn.

  However, in this embodiment, the second resin material is injected into the second cavity C <b> 2 after confirming the form in which the plunger 72 is surely withdrawn from the flange portion 12 a of the primary molded product 12 by the limit switch 74. Therefore, the filling pressure of the second resin material filled in the second cavity C2 does not change (decrease) in the middle, and stable injection molding can be performed. Further, the plunger 72 with the molten resin attached to the tip does not retreat, and the smooth driving of the hydraulic cylinder 70 (smooth operation of the plunger 72) is not hindered.

Further, in order to prevent the occurrence of “color cast” at the peripheral portion of the two-color molded product, the peripheral portion 12 a of the primary molded product 12 can be used before the injected second resin material reaches the plunger 72. The timing for retracting the plunger 72 is more effective as late as possible. Further, although it depends on the injection pressure and flow velocity of the second resin material, the arrival time from the side valve gate to the nearest plunger 72 takes a predetermined time (for example, 0.5 seconds). Therefore, after the opening of the side valve gate 80, a predetermined time (e.g., 0.5 sec) so as to coordinate such plunger 72 is to leave after the elapse, the driving of the opening operation and the hydraulic cylinder 70 of the side valve gate 80 Also good.

  In the above embodiment, the hydraulic cylinders 70 are described as being disposed at a plurality of locations on each cavity-side mold 58A, 58B, but the configuration is such that the hydraulic cylinder 70 is disposed at only one location. In addition, depending on the shape of the primary molded product 12, it is possible to prevent detachment from the cavity side molds 58A and 58B.

  In the above embodiment, the plunger 72 of each hydraulic cylinder 70 is configured to protrude into the first cavity C1 from a direction parallel to the mold closing / opening direction, but the primary from the cavity side mold 58A. As long as it is within a range in which the molded product 12 can be prevented from being detached, it is possible to project the first cavity C1 from a direction inclined with respect to the mold closing / opening direction.

  In the said embodiment, although the two-color molded product 10 used as the object of injection molding was demonstrated as what is a translucent cover of a vehicle lamp, it aimed at other resin molded products, such as a sunroof and a rear window, for example. Even in this case, the same effect as that of the above embodiment can be obtained.

  Next, a modification of the above embodiment will be described. FIG. 8 is a view similar to FIG. 6G, showing an outline of the injection molding method according to the present modification.

  As shown in the figure, also in this modification, the configuration of the two-color molded product 10 that is the object of injection molding is the same as that in the above embodiment, and the configuration of the mold 150 is also primary. The structure itself of the core side mold 152 and the secondary core side mold 154 and the pair of cavity side molds 158A and 158B is the same as that in the above embodiment, but the arrangement is different from that in the above embodiment. Yes.

  That is, the mold 150 is a so-called rotary type two-color molding mold, and the primary core side mold 152 and the secondary core side mold 154 are arranged upward at positions apart from each other, Between the primary core side mold 152 and the secondary core side mold 154, a pair of cavity side molds 158 </ b> A having the same shape are arranged on a rotating member 156 that is rotatably arranged around the Y axis extending in the vertical direction. 158B is arranged in a downward direction. The pair of cavity side molds 158A and 158B move in the vertical direction together with the rotating member 156, whereby the primary core side mold 152 and the secondary core side mold 154 and the pair of cavity side molds 158A, Mold closing and mold opening with 158B are performed.

  Specifically, the first cavity side mold 158 </ b> A constitutes a primary molding mold for molding the primary molded product 12 in cooperation with the primary core side mold 152 and is integrated with the rotating member 156. By rotating 180 degrees, the primary molding die for molding the secondary molded product 14 is configured in cooperation with the secondary core side die 154. On the other hand, the second cavity side mold 158B constitutes a primary molding mold for molding the primary molded product 12 in cooperation with the primary core side mold 152 and is integrated with the rotating member 156. By rotating 180 degrees, a secondary molding die for molding the secondary molded product 14 is configured in cooperation with the secondary core side die 154.

  When the cavity side molds 158A and 158B are used as the primary molding mold, the plunger 172 of each hydraulic cylinder 170 is protruded into the first cavity for molding the first molded product 12. When the next molded product 12 is molded, on the other hand, when the cavity side molds 158A and 158B are used as secondary molds, the plunger 172 of each hydraulic cylinder 170 is retracted from the cavity between the molds. The secondary molded product 14 is molded.

  Even when the configuration of the present modification is adopted, for example, the plunger 172 of the hydraulic cylinder 170 is penetratingly engaged with the peripheral portion of the primary molded product 12 from the direction parallel to the mold closing / opening direction. As shown in FIG. 8, when the primary core side mold 152 and the cavity side mold 158B are opened, the primary molded product 12 is held in the cavity side mold 158B while the primary core side mold 152 is held. The primary molded product 12 is maintained in the cavity-side mold 158B without being displaced by centrifugal force or impact force when the rotating member 156 is rotated. Become.

  Also in this modified example, the second resin material is second by the plunger 172 of the hydraulic cylinder 170 protruding from the molding surface of the cavity-side mold 158B and penetrating through the flange portion 12a of the primary molded product 12. The primary molded product 12 is held in such a manner that the whole of the primary molded product 12 including the peripheral edge portion 12a is in close contact with the molding surface of the cavity side mold 158B until just before the lamination molding of the secondary molded product is started. The Therefore, a so-called “color cast” in which a part of the second resin material injected into the second cavity wraps around between the peripheral edge of the primary molded product and the molding surface of the cavity side mold does not occur. .

  Further, when the secondary molded product 14 is injection-molded in the form in which the plunger 172 of the hydraulic cylinder 170 is retracted, the through-hole 12d which is a trace when the plunger 172 is extracted from the flange portion 12c is formed in the flange of the primary molded product 12. Although formed in the portion 12c, a part of the second resin material constituting the secondary molded product 14 is filled into the through hole 12d and molded and integrated.

  For this reason, as shown in FIG. 2, the through-hole 12d formed in the flange portion 10Ba of the molded two-color molded product 10 (the flange portion 12c of the primary molded product 12) has a secondary molded product on the back side. The convex portion 14b on the 14 side is engaged, and the peripheral region 12d1 of the through hole 12d of the primary molded product 12 and the end surface 14a of the convex portion 14b exposed to the through hole 12d are the flange portion 10Ba of the two-color molded product 10. A continuous front surface of the flange portion 12c of the primary molded product 12 is formed.

  Thus, also in this modification, the same operation effect as the above-mentioned embodiment can be obtained.

  Further, the present invention is not limited to the configurations described in the above embodiment and its modifications. For example, the specific configuration of the “in / out mechanism” is not particularly limited, and a configuration with various changes such as an air cylinder or the like in addition to the hydraulic cylinder can be used.

DESCRIPTION OF SYMBOLS 10 Two-color molded product 10A Front surface part 10B Peripheral surface part 10Ba Flange part 10Bb Annular projection part 12 Primary molded product 12c Flange part provided in the peripheral part of the primary molded product 12d Through-hole 14 Secondary molded product 14a In a through-hole Convex part 14b Convex part end face 50, 150 Mold 52, 152 Primary core side mold 54, 154 Secondary core side mold 56, 156 Rotating member 58A, 58B, 158A, 158B Cavity side mold 58a Molding surface provided on cavity side mold 58A 58b Molding surface provided on cavity side mold 58B 62 Movable plate 64 Fixed plate 66, 68 Heating cylinder 70, 170 Hydraulic cylinder (extruding mechanism)
72, 172 Plunger (protrusion)
74 Limit switch which is a sensor provided in the hydraulic cylinder 80 Side valve gate C1 First cavity C2 Second cavity

Claims (5)

A method of injection molding a two-color molded product in which a secondary molded product is laminated and disposed on a peripheral portion of a primary molded product,
Injecting the first resin material into the first cavity formed by closing the cavity side mold and the primary core side mold to mold the primary molded product,
Next, a second resin material is injected into a second cavity formed by closing the cavity side mold and the secondary core side mold for holding the primary molded product, and the primary resin is injected. When laminating the secondary molded product on the periphery of the molded product,
In the cavity-side mold, an intrusion mechanism configured to project at least one protrusion at a portion corresponding to a peripheral edge of the primary molded product of the first cavity is arranged,
The primary molded product is molded in a form in which the protrusion protrudes across a portion corresponding to the peripheral edge of the primary molded product of the first cavity,
Thereafter, when the second resin material is injected into the second cavity to laminate the secondary molded product, the protrusion is retreated to the molding surface of the cavity side mold. Injection molding method.   2. The injection molding method according to claim 1, wherein the second resin material is injected after the retraction of the protrusion is confirmed by a sensor provided in the retracting mechanism. A mold for injection molding a two-color molded product in which a secondary molded product is laminated and disposed on the peripheral edge of the primary molded product,
A primary molding die which is composed of a cavity side mold and a primary core side mold, and injects a first resin material into a first cavity formed by closing the mold to mold the primary molded product. Type,
A second cavity formed by closing the cavity side mold and the secondary core side mold, which is configured by the cavity side mold and the secondary core side mold and holds the primary molded product. A second molding material for injecting a second resin material and laminating and molding the secondary molded product on the periphery of the primary molded product;
A protrusion / displacement mechanism that is arranged on the cavity side mold and that is configured so that a protrusion that can move forward and backward protrudes into a portion corresponding to a peripheral edge of the primary molded product of the first cavity and traverses the portion. and, with a,
When the primary molded product is molded, the protruding portion of the protrusion / projection mechanism protrudes into the first cavity of the primary molding die, and the secondary molded product is formed at the peripheral portion of the primary molded product. A mold configured to retreat to the molding surface position of the cavity-side mold when layering is performed .   4. The mold according to claim 3, wherein a tip portion of the protruding portion of the intrusion mechanism is formed in a shape that follows a molding surface of a cavity-side mold that forms the first cavity.   The mold according to claim 3 or 4, wherein a sensor for confirming the withdrawal of the protrusion is provided in the intruding mechanism.

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