JP2006205580A - Ring-shaped product made of resin and its injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the design properties of a molded ring-shaped product made of a resin by suppressing the development of a weldline when the ring-shaped product is injection-molded. <P>SOLUTION: A mold (fixed mold 9) is constituted by forming two resin sump parts 21 in the vicinity of a confluent part 23, where a thermoplastic resin R flows through a cavity 13 in a mutually opposite direction at the time of injection molding and the respective flows of the thermoplastic resin R meet with each other, so that the resin sump parts 21 become point symmetry with respect to the center 23a of the confluent part 23 and an iris part 21a is provided to the boundary with the cavity 13. The flows of the thermoplastic resin R injected in the cavity 13 of the mold (fixed mold 9) are allowed to meet with each other at the confluent part 23 and subsequently introduced into the resin sump parts 21 on the downstream side of the confluent part 23 to mold the ring-shaped product. The resin solids solidified in both resin sump parts 21 are demolded to be cut off from the ring-shaped product. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin-made ring-shaped product having a metallic feeling and an injection molding method thereof, and more particularly to measures for aligning a glossy material.

  Conventionally, when a resin ring-shaped product is injection-molded, as shown in FIG. 8, the thermoplastic resin b injected into the cavity a flows in the cavity a in opposite directions as indicated by arrows and merges. There has been a problem that the weld line c is generated due to the incomplete fusion of the thermoplastic resin b and the design property is lowered.

On the other hand, in Patent Document 1, by providing a resin reservoir part for introducing a part of the thermoplastic resin in the vicinity of the gate of the outer peripheral edge of the cavity, that is, at a place away from the joining part where the thermoplastic resin joins, The pressure balance at each tip portion of the thermoplastic resin flowing in the opposite direction is broken, and thereby, the thermoplastic resin is intertwined in a complicated manner at the joining portion so as to improve the rigidity of the molded product at the joining portion.
Japanese Patent Laid-Open No. 2002-301742 (pages 2, 5 and 4)

  By the way, when a ring-shaped product having a metallic feeling is formed by injecting a thermoplastic resin containing a gloss material such as an aluminum piece into the cavity, the method of Patent Document 1 described above complicates the thermoplastic resin at the junction. Since they are entangled with each other, the orientation of the glossy material is disturbed at the joining portion, the expression of the weld line becomes remarkable, and the design property is lowered.

  The present invention has been made in view of such points, and the object of the invention is to suppress the appearance of the weld line when injection molding a resin ring-shaped product, and to improve the design of the molded ring-shaped product. It is to improve.

  In order to achieve the above object, the present invention is characterized in that the orientation of the glossy material is corrected in the vicinity of the junction where the thermoplastic resin flows merge.

  Specifically, the invention according to claims 1 to 3 is directed to a resin ring-shaped product formed by injecting a thermoplastic resin containing a gloss material into a cavity, and has the following means for solving the problem. I took it.

  That is, the invention described in claim 1 is provided integrally with the ring-shaped product main body, and the outer peripheral edge and the inner peripheral edge of the ring-shaped product main body, and the narrow part is formed at the boundary with the ring-shaped product main body. The protrusions of the outer peripheral edge are protruded corresponding to the vicinity of the merge part where the thermoplastic resins flow in opposite directions in the cavity and merge at the time of injection molding. The projecting portion is characterized in that the projecting portion is integrally projected on the ring-shaped product main body so as to be point-symmetric with respect to the projecting portion of the outer peripheral edge portion with the center of the joining portion as a starting point.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, at least one of the protrusions is a locking claw for attaching a ring-shaped product to another member.

  According to a third aspect of the present invention, in the first aspect of the present invention, at least one of the protrusions is a positioning rib for positioning when attaching the ring-shaped product to another member.

  The invention according to claim 4 has taken the following solution for an injection molding method in which a thermoplastic ring-shaped product is molded by injecting a thermoplastic resin containing a gloss material into a cavity.

  In other words, the invention according to claim 4 includes two symmetric points starting from the center of the merging portion in the vicinity of the merging portion where the thermoplastic resins flow in opposite directions in the cavity and merge at the time of injection molding. Prepare a molding die that has a resin introduction space so as to have a constricted portion at the boundary with the cavity. After the thermoplastic resin injected into the cavity of the molding die joins at the junction, each downstream A ring-shaped product is formed by introduction into the resin introduction space on the side, and the solid resin solidified in both the resin introduction spaces is removed from the ring-shaped product as necessary after demolding.

  According to the first aspect of the present invention, the protrusions serving as the resin reservoirs are respectively provided on the inner peripheral edge and the outer peripheral edge of the ring-shaped product main body corresponding to the vicinity of the merge portion where the thermoplastic resin merges. Therefore, the thermoplastic resin once joined at the joining portion in the cavity at the time of molding is introduced into the cavity space corresponding to each downstream protruding portion. As a result, the turbulent flow of the thermoplastic resin is corrected to the original flow, and along with this, the orientation of the glossy material contained in the thermoplastic resin returns to the original state and is aligned in one direction. The expression of the weld line due to the disorder of the orientation of the glossy material can be suppressed in the vicinity of the portion, and a resin-made ring-shaped product with high design properties can be obtained.

  According to the invention which concerns on Claim 2, since the cavity space of the latching claw for attaching a ring-shaped product to another member is utilized as a resin reservoir part, the latching claw (resin reservoir part) is excised after molding. This eliminates the need for material waste and simplifies the work process.

  According to the invention of claim 3, since the cavity space of the positioning rib for attaching the ring-shaped product to the other member is used as the resin reservoir, the same effect as that of claim 1 can be obtained.

  According to the invention which concerns on Claim 4, when the resin solid substance solidified by the resin introduction space part becomes the obstruction at the time of attaching a ring-shaped article to another member, for example, it cuts out or the said resin solid substance If there is no adverse effect on the appearance of the ring-shaped product, it can be dealt with as needed, such as leaving it without being cut off.

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

(Embodiment 1)
FIG. 5 shows a bumper 1 of an automobile, and fog lamps 3 are attached to both ends of the bumper 1 in the vehicle width direction. A resin ring-shaped product 5 according to Embodiment 1 is attached to the outer peripheral edge of the fog lamp 3.

  The ring-shaped product 5 is injection molded using a molding die 7 as shown in FIGS. The molding die 7 includes a fixed die 9 and a movable die 11, and two substantially rectangular cavities 13 are formed side by side on the fixed die 9. These cavities 13 are connected to a nozzle of an injection machine (not shown) through a gate 15, a runner 17 and a sprue 19. Two resin reservoirs 21 serving as two resin introduction spaces are formed at positions substantially opposite to the gate 15. As shown in an enlarged view in FIG. 2, these resin reservoirs 21 are formed in the vicinity of the junction 23 where the thermoplastic resin R flows in the opposite directions in the cavity 13 and merges at the time of injection molding. 23 is formed at a point-symmetrical position starting from the center 23 a of the 23, and a constriction 21 a is provided at the boundary between the resin reservoir 21 and the cavity 13.

  Next, an injection molding method for the ring-shaped product 5 will be described.

  First, the mold 7 is clamped, and the thermoplastic resin R containing the gloss material is injected from the nozzle of the injection machine into the cavity 13 through the sprue 19, the runner 17 and the gate 15. The thermoplastic resins R injected into the cavities 13 flow in opposite directions and merge at the merging portion 23 and then are introduced into the respective resin reservoirs 21 on the downstream side. At this time, in the merging portion 23, the thermoplastic resins R that have flowed in opposite directions collide with each other, and then the flow is temporarily disturbed. Thereafter, the flow is introduced into the respective downstream resin reservoirs 21 to cause the flow of the thermoplastic resin R to flow. The original orientation is corrected, and along with this, the orientation of the glossy material contained in the thermoplastic resin R is also aligned in one direction and returns to the original state.

  Next, the thermoplastic resin R is solidified in the cavity 13 to form a substantially rectangular ring-shaped product 5. This ring-shaped product 5 includes a ring-shaped product main body 27 and a plurality of locking claws 29 that are integrally projected on the outer peripheral edge of the ring-shaped product main body 27, and the ring-shaped product 5 5 is attached to the outer peripheral edge of the fog lamp 3 as another member. Further, a solid resin material 31 as a protruding portion solidified in the resin reservoir portion 21 is provided on the side substantially opposite to the gate 15, and a narrow portion 31a is formed at a position corresponding to the throttle portion 21a. Further, the ring-shaped product 5 is attached with sprue runner resin solids (portions formed by 25 of the fixed mold 9 shown in FIG. 1) solidified in the gate 15, the runner 17 and the sprue 19.

  Thereafter, the mold 7 is opened to remove the ring-shaped product 5, and the solid resin 31 solidified in the two resin reservoirs 21 and the sprue runner resin solidified in the gate 15, runner 17 and sprue 19. Solid matter is excised from the ring-shaped product 5. Since the ring-shaped product 5 molded in this manner has the glossy material aligned in one direction as described above at the time of molding, the occurrence of a weld line due to the disturbance of the glossy material orientation is suppressed in the vicinity of the junction 23. It is possible to obtain a ring-shaped product 5 having a high design property.

  In the first embodiment, the resin solid material 31 is cut out from the ring-shaped product 5. However, depending on the shape of the resin solid material 31, the resin solid material 31 is not obstructed or does not adversely affect the appearance. It may be left without being excised.

(Embodiment 2)
FIG. 6 shows the second embodiment. In the second embodiment, the latching claw 29 is used in place of the resin reservoir 21 as the resin introduction space in the first embodiment. 1, the description of the overall configuration of the ring-shaped product 5 is omitted.

  That is, two rectangular stealing portions 33 are formed at one base end of the plurality of locking claws 29, and thereby two narrow portions 29 a are formed at the boundary with the ring-shaped product body 27. Yes. The locking claw 29 having the narrowed portion 29a is projected at a position corresponding to the vicinity of the joining portion 23 where the thermoplastic resin R flows in opposite directions into the cavity 13 and joins at the time of injection molding. Further, on the opposite side between the locking claw 29 and the ring-shaped product 5, another locking claw 29 having a narrow portion 29 a at the boundary with the ring-shaped product main body 27 is provided on the junction portion 23. The ring-shaped product main body 27 is integrally projected so as to be point-symmetric with respect to the center 23a. The two locking claws 29 having these narrow portions 29a function as the resin reservoir portion 21 of the first embodiment.

  Therefore, in the second embodiment, the flow of the thermoplastic resin R is corrected to the original flow at the junction 23 as in the first embodiment, and the orientation of the glossy material is restored to the original state accordingly. The ring-shaped product 5 having high design properties can be obtained by arranging in one direction and suppressing the expression of the weld line.

  In addition, since the cavity space of the locking claw 29 for attaching the ring-shaped product 5 to the outer peripheral edge of the fog lamp 3 is used as the resin reservoir, the locking claw 29 (resin reservoir) is cut off after molding. This eliminates the need for material waste and simplifies the work process.

(Embodiment 3)
FIG. 7 shows a third embodiment. In this third embodiment, positioning is performed when the ring-shaped product 5 is attached to the fog lamp 3 instead of the resin reservoir portion 21 as the resin introduction space portion of the first embodiment. Since the configuration is the same as in the first embodiment except that the rib 35 is used, the description of the overall configuration of the ring-shaped product 5 is omitted.

  That is, a plurality of the positioning ribs 35 are integrally projected on the outer peripheral edge of the ring-shaped product main body 27. One of the positioning ribs 35 has a narrow portion 35a at the boundary with the ring-shaped product main body 27, and the joining portion 23 where the thermoplastic resins R flow in opposite directions in the cavity 13 and merge at the time of injection molding. It protrudes corresponding to the vicinity. On the opposite side of the positioning rib 35 and the ring-shaped article body 27, another positioning rib 35 having a narrow portion 35a at the boundary with the ring-shaped article body 27 starts from the center 23a of the junction 23. Are integrally projected on the ring-shaped product main body 27 so as to be point-symmetric.

  Therefore, in the third embodiment, the flow of the thermoplastic resin R is corrected to the original flow at the junction 23 as in the first embodiment, and the orientation of the glossy material is also restored to the original state accordingly. A ring-shaped product 5 having a high design property is obtained in which the arrangement of the weld lines is suppressed in an orderly manner in one direction.

  In addition, since the cavity space of the positioning rib 35 that is positioned when attaching the ring-shaped product 5 to the fog lamp 3 is used as the resin reservoir, it is not necessary to cut the positioning rib 35 (resin reservoir) after molding, Waste of material can be eliminated and the work process can be simplified.

  In the first embodiment, a plurality of locking claws 29 are integrally projected on the outer peripheral edge of the ring-shaped product main body 27, and in the second embodiment, a plurality of positioning ribs 35 are provided on the outer peripheral edge of the ring-shaped product 5. However, these may be integrally projected on the inner peripheral edge of the ring-shaped product 5. In this case, one of the plurality of locking claws 29 and the positioning rib 35 is provided as a resin introduction space portion (resin reservoir portion) by providing the narrow portions 29a and 35a, and the locking claw 29 and the positioning rib 35 are used. 35 and the ring-shaped product body 27 are sandwiched between the other claw 29 and the positioning rib 35 having narrow portions 29a, 35a on the outer peripheral edge on the opposite side, and are symmetrical with respect to the center 23a of the junction 23. Thus, the ring-shaped product main body 27 is integrally projected.

  Moreover, in each embodiment, as two protrusion parts which protruded from the ring-shaped article main body 27 so as to correspond to both sides of the merge part 23 of the thermoplastic resin R, the resin solids 31 solidified in the resin reservoir part 21 Positioning is performed when the combination (Embodiment 1), the locking claws 29 that attach the ring-shaped product to the outer peripheral edge of the fog lamp 3 (Embodiment 2), or the ring-shaped product is attached to the outer peripheral edge of the fog lamp 3 Although the positioning ribs 35 are the same (Embodiment 3), these three members may be combined.

  The present invention is useful for a resin ring-shaped product having a metallic feeling and an injection molding method thereof.

It is a front view of the fixed mold | type of the state which shape | molded the ring-shaped goods in Embodiment 1. FIG. FIG. 3 is an enlarged view showing the vicinity of a joining portion of a thermoplastic resin in a cavity in the first embodiment. It is sectional drawing equivalent to the AA line of FIG. It is sectional drawing equivalent to the BB line of FIG. It is a front view of a bumper. The ring-shaped goods of Embodiment 2 are shown, (a) is sectional drawing equivalent to FIG. 3, (b) is the figure which looked at the latching claw of (a) from the front. It is sectional drawing of the positioning rib protrusion location of the ring-shaped goods in Embodiment 3. FIG. This is a conventional example corresponding to FIG.

Explanation of symbols

5 Ring-shaped product 7 Mold 13 Cavity 21 Resin reservoir (resin introduction space)
21a Restriction part 23 Merge part 23a Center of merge part 27 Ring-shaped product body 29 Locking claw (protrusion part)
29a Narrow part 31 Resin solid (protruding part)
35 Positioning rib (protrusion)
35a Narrow part R Thermoplastic resin

Claims (4)

A resin ring-shaped product molded by injecting a thermoplastic resin containing a glossy material into the cavity,
A ring-shaped product body;
A projecting portion provided integrally with an outer peripheral edge portion and an inner peripheral edge portion of the ring-shaped product main body, and having a narrow portion at the boundary with the ring-shaped product main body,
The protruding portion of the outer peripheral edge portion is provided corresponding to the vicinity of the joining portion where the thermoplastic resin flows in the opposite directions in the cavity and merges during injection molding,
The protruding portion of the inner peripheral edge portion is integrally protruded from the ring-shaped product main body so as to be point-symmetric with respect to the protruding portion of the outer peripheral edge portion, starting from the center of the merging portion. Plastic ring-shaped product. In the resin ring-shaped product of claim 1,
At least one protrusion is a locking claw for attaching the ring-shaped product to another member. In the resin ring-shaped product of claim 1,
At least one protrusion is a positioning rib for positioning when attaching a ring-shaped product to another member. An injection molding method for molding a resin ring-shaped product by injecting a thermoplastic resin containing a gloss material into a cavity,
The two resin introduction spaces are narrowed at the boundary with the cavity so that the thermoplastic resin flows in opposite directions in the cavity at the time of injection molding and merges in the vicinity of the junction where the center of the junction is the starting point. Prepare a molding die formed to have a part,
After the thermoplastic resin injected into the mold cavity is merged at the merging portion, it is introduced into each downstream resin introduction space portion to form a ring-shaped product, and both the resin introduction space portions are An injection molding method for a resin ring-shaped product, wherein the solidified resin solid material is removed from the ring-shaped product as necessary after demolding.

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