JP2010082967A - Injection molding die and manufacturing method of thermoplastic resin molding - Google Patents

Abstract

An object of the present invention is to provide a mold for injection molding capable of molding a thermoplastic resin molded article having a good appearance and a method for producing a thermoplastic resin molded article.
The present invention relates to an injection mold 1 including a fixed mold 4 and a movable mold 5 that form a cavity 7 into which a thermoplastic resin is injected, the cavity surface 18a of the fixed mold 4 and At least one of the cavity surfaces 19a of the movable mold 5 is formed with a plurality of grooves 20 extending in a direction substantially parallel to the flow direction of the thermoplastic resin and contacting the thermoplastic resin with the inner wall 20a. At least one of the interval between the grooves 20, the depth of the plurality of grooves 20, and the width of the plurality of grooves 20 is non-uniform.
[Selection] Figure 5

Description

  The present invention relates to an injection mold and a method for producing a thermoplastic resin molded body.

  Conventionally, as an injection mold used for injection molding of a thermoplastic resin, for example, the one described in Patent Document 1 is known. The injection mold described in Patent Document 1 is fixed to an injection molding machine via a mold mounting plate, and is held by a manifold part that forms a flow path of molten resin, and a manifold part via a heat insulating plate. The first mold and the second mold for forming a cavity between the first mold and maintaining the flatness of the cavity surface of the mold by the manifold portion, Generation, that is, appearance defects are suppressed.

JP 2000-15665 A

  However, the above-described conventional injection mold has a problem that, for example, appearance defects such as sink marks are likely to occur in the molded product at the end of the flow.

  This invention is made | formed in view of such a situation, and provides the manufacturing method of the injection mold which can shape | mold the thermoplastic resin molded object of a favorable external appearance, and a thermoplastic resin molded object. With the goal.

  An injection mold according to the present invention includes first and second molds that form a cavity into which a thermoplastic resin is injected, and the flow of the thermoplastic resin that has flowed into the cavity from a gate that is an inlet of the cavity. An injection mold in which a thermoplastic resin is filled in a cavity by reaching the end of the flow of the thermoplastic resin in the cavity, the cavity surface of the first mold and the cavity of the second mold At least one of the surfaces is formed with a plurality of grooves extending in a direction substantially parallel to the flow direction of the thermoplastic resin, the interval between the plurality of grooves, the depth of the plurality of grooves, and the plurality of grooves At least one of the widths is non-uniform.

  The method for producing a thermoplastic resin molded body according to the present invention includes an injection step of injecting a molten thermoplastic resin into a cavity formed by the first and second molds, and a molten thermoplastic resin injected into the cavity. A cooling step for cooling the resin, and at least one of the cavity surface of the first mold and the cavity surface of the second mold extends in a direction substantially parallel to the flow direction of the thermoplastic resin, and is formed on the inner wall. A plurality of grooves in contact with the thermoplastic resin are formed, and at least one of the intervals between the plurality of grooves, the depths of the plurality of grooves, and the widths of the plurality of grooves is non-uniform.

  The reason why appearance defects such as sink marks occur is that the cooling rate of the resin is slower in that portion than in other portions. For example, since the filling pressure is lower on the end side of the flow than on the gate side, the resin is insufficiently filled on the end side of the flow, and the adhesion between the resin and the mold is reduced, compared to the gate side. It is considered that the cooling rate of the resin is reduced. According to the present invention, even when the plurality of grooves extend in a direction substantially parallel to the flow direction of the thermoplastic resin, the flow of the resin into the cavity is hardly affected when the thermoplastic resin is injected. Furthermore, the plurality of grooves having a predetermined non-uniform configuration formed on the cavity surface extend in a direction substantially parallel to the flow direction of the thermoplastic resin, so that resin filling into the grooves is promoted and injected into the cavity. The contact area between the melted thermoplastic resin and the mold is increased. As a result, the resin cooling rate in the portion where the plurality of grooves on the cavity surface are formed can be improved, so that the occurrence of sink marks or the like in the portion can be suppressed, and the thermoplastic resin molded body having a good appearance can be obtained. Can be formed.

  Here, it is preferable that the plurality of grooves are formed on the end side of the flow of the thermoplastic resin in the cavity surface. Here, the end side of the flow of the thermoplastic resin in the cavity is based on the intermediate point between the gate which is the entrance of the cavity and the end of the flow where the flow of the thermoplastic resin flowing in from the gate finally reaches, It means at least a part of the region closer to the end of the flow than this intermediate point. Since the end of the thermoplastic resin flow is particularly prone to sink, it is possible to effectively suppress the occurrence of sink or the like.

  Moreover, it is preferable that a plurality of grooves extending in a direction substantially orthogonal to the flow direction of the thermoplastic resin is further formed on the gate side of the cavity surface where the plurality of grooves are formed. Here, in the cavity, the gate side is closer to the gate than the intermediate point with reference to the intermediate point between the gate that is the entrance of the cavity and the end of the flow of the thermoplastic resin that has flowed in from the gate at the end. Means at least a part of the area.

  According to such a configuration, the plurality of grooves extending in a direction substantially orthogonal to the flow direction of the thermoplastic resin temporarily prevents the resin from filling into these grooves, thereby suppressing the cooling of the resin, and the flow It becomes easy to fill the resin first on the end side of the. Thereby, sink marks on the end side of the flow can be further suppressed. The gate side has a plurality of grooves extending in a direction substantially perpendicular to the flow direction of the thermoplastic resin, and even if the filling of the resin into the grooves is hindered, the filling pressure is higher than the flow end side. Since it is easy, sinking is less likely to occur on the gate side.

  ADVANTAGE OF THE INVENTION According to this invention, the thermoplastic resin molded object of a favorable external appearance can be shape | molded.

  Hereinafter, preferred embodiments of an injection mold according to the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part and the overlapping description is abbreviate | omitted. Further, as shown in the drawings, the X axis and the Y axis are 90 degrees on the horizontal plane, the vertical direction is defined as the Z axis direction, and the X axis, Y axis, and Z axis are used below when necessary.

  As shown in FIGS. 1 and 2, an injection mold 1 used for injection molding of a thermoplastic resin molded body includes a fixed-side mounting plate 2 and a movable-side mounting that are arranged to face each other in the X-axis direction. And a plate 3. The fixed side mounting plate 2 is fixed to the side of the injection device that injects a molten thermoplastic resin, and the movable side mounting plate 3 reciprocates in the X-axis direction by a mold opening / closing mechanism (not shown).

  Between the fixed-side mounting plate 2 and the movable-side mounting plate 3, a fixed-side mold (first mold) 4 and a movable-side mold (second mold) 5 are arranged to face each other in the X-axis direction. . The fixed side mold 4 is configured to be movable in the X-axis direction and is guided by four guide pins 6 protruding from the inner surface of the fixed side mounting plate 2. The movable die 5 is fixed to the movable attachment plate 3 via a spacer block 10 and a receiving plate 11 which will be described later, and reciprocates in the X-axis direction as the movable attachment plate 3 moves.

  The fixed-side mold 4 and the movable-side mold 5 include a closed state (see FIG. 1) in which the fixed-side mold 4 and the movable-side mold 5 are in contact with the reciprocating movement of the movable-side mounting plate 3, and the fixed-side mold 4. And an open state (see FIG. 2) in which the movable mold 5 is separated. In the closed state, the fixed side mold 4 and the movable side mold 5 form a rectangular plate-shaped cavity 7 therein.

  A substantially funnel-shaped sprue bush 8 into which a nozzle tip of an injection device (not shown) enters is provided at the center of the fixed side mounting plate 2. Further, a runner stopper plate 9 penetrating the guide pin 6 is disposed between the fixed side mounting plate 2 and the fixed side mold 4, and the runner stopper plate 9 and the fixed side mold 4 are in a molten state. The runner molding part 12 which comprises the flow path of a thermoplastic resin is formed. The runner molding portion 12 is connected to the outlet side of the sprue bushing 8.

  In the fixed side mold 4, a sprue molding portion 13 that penetrates the fixed side mold 4 in the X-axis direction is formed. Further, a gate molding portion 14 that forms the entrance of the cavity 7 is formed between the fixed side mold 4 and the movable side mold 5. The gate molding portion 14 and the runner molding portion 12 communicate with each other via a sprue molding portion 13.

  A receiving plate 11 is fixed to the surface of the movable mold 5 opposite to the cavity 7. An ejector plate 17 that holds four ejector pins 16 for removing the thermoplastic resin molded body solidified in the cavity 7 from the mold is provided between the receiving plate 11 and the movable side mounting plate 3. . Spacer blocks 10 are disposed between the receiving plate 11 and the movable mounting plate 3 on both sides of the ejector plate 17 that moves in the X-axis direction.

  As shown in FIGS. 3 and 4, a metal plate 18 is provided on the cavity 7 side of the stationary mold 4. The metal plate 18 is made of metal such as aluminum, zinc alloy, nickel, nickel alloy, copper, copper alloy, as well as steel and SUS, for example. A surface (hereinafter, referred to as “cavity surface”) 18 a that forms the cavity 7 in the metal plate 18 is formed in, for example, an uneven shape corresponding to a design surface pattern of a thermoplastic resin molded body to be molded.

  A metal plate 19 is provided on the cavity 7 side of the movable mold 5. The metal plate 19 may be the same material as the metal plate 18 or may be a different material. The cavity surface 19a of the metal plate 19 corresponds to the non-design surface of the molded body. As shown in FIGS. 5A to 5C, a plurality of grooves 20 extending in a direction substantially parallel to the flow direction of the thermoplastic resin is formed in at least a part of the cavity surface 19a. . Here, G in FIG. 5 shows a gate which is the entrance of the cavity 7, and E is the end of the flow of the thermoplastic resin injected from the gate G, that is, the flow of the thermoplastic resin flowing into the cavity 7 is the last. Indicates where to reach. The direction of the flow of the thermoplastic resin is a direction from the gate G toward the end E of the flow.

  For example, as shown in FIG. 5A, a plurality of grooves 20 may be formed on the entire surface of the cavity surface 19a. Further, as shown in FIG. 5B, a plurality of grooves 20 extending in a direction substantially parallel to the flow direction of the thermoplastic resin are formed only on the end E side in the flow direction of the thermoplastic resin on the cavity surface 19a. It is also preferable. Further, as shown in FIG. 5 (c), a plurality of grooves 20 extending in a direction substantially parallel to the flow direction of the thermoplastic resin are formed only on the end E side in the flow direction of the thermoplastic resin. More preferably, a plurality of grooves 21 extending in a direction substantially perpendicular to the flow direction of the thermoplastic resin is formed on the gate G side of the plastic resin.

  Specifically, as shown in FIG. 6, the plurality of grooves 20 includes an interval between the grooves 20 (interval between the central axis of the groove and the central axis of the adjacent groove), and a depth of each groove (a groove is formed). Difference between the highest point and the lowest point in the two walls) and the width of each groove (the distance between the highest points of the two walls forming the groove) are non-uniform to each other ing. The groove 20 shown in FIG. 6A can be formed by polishing the cavity surface 19a in a predetermined direction using, for example, sand paper, and the groove shown in FIG. 6B is formed by cutting. In addition, the grooves shown in FIG. 6C can be formed by floating abrasive processing by sandblasting or the like. The plurality of grooves 20 may be formed by electric discharge machining, electroforming, or the like. For example, a plate in which the plurality of grooves 20 are formed by sand paper may be arranged on the cavity surface 19 like a nest.

  The dimension of the groove 20 is not particularly limited. For example, the width is preferably 1 to 200 μm. The depth is preferably 1 to 100 μm. Further, the aspect ratio (depth / width) of the groove is preferably 0.1 or more, particularly preferably 0.2 to 5.0. The interval between the grooves is preferably about 1 to 200 μm.

  Further, the plurality of grooves 21 extending in a direction substantially perpendicular to the flow direction of the thermoplastic resin may be the same as the plurality of grooves 20 except for the direction, but the interval between the grooves 21, the depth of the grooves, and the groove The width may be uniform.

  Next, a method for producing a thermoplastic resin molded body in the injection mold 1 having the above configuration will be described. First, a thermoplastic resin is put into an injection apparatus to prepare a molten thermoplastic resin that becomes a base material of a thermoplastic resin molded body.

  Here, the thermoplastic resin is not particularly limited. For example, polypropylene, polyethylene, acrylic, acrylonitrile-styrene-butadiene block copolymer, polyamide such as polystyrene, nylon, polyvinyl chloride, polycarbonate, acrylic resin, styrene-butadiene block. Examples thereof include general thermoplastic resins such as copolymers, thermoplastic elastomers such as EPM and EPDM, mixtures thereof, and polymer alloys using these.

  In addition, these thermoplastic resins may contain fillers such as glass fibers that are usually used, various inorganic and organic fillers, and the like as necessary. Moreover, various additives, such as various stabilizers, a dispersing agent, a ultraviolet absorber, a mold release agent, a lubricant, an antistatic agent, a pigment, etc. which are normally used may be contained.

  In the injection mold 1 according to the present embodiment, first the fixed side mold 4 and the movable side mold 5 are closed, and then the molten thermoplastic resin is injected in the direction of arrow A by the injection device. Inject into the sprue bushing 8. The thermoplastic resin injected into the sprue bushing 8 includes a runner molding portion 11 between the runner stopper plate 9 and the fixed side die 4, a sprue molding portion 12 of the fixed side die 4, and the fixed side die 4 and the movable side die. 5 flows into the cavity 7 through the gate forming portion 13 between the two and the flow reaches the end of the flow of the thermoplastic resin in the cavity 7, so that the thermoplastic resin is filled in the cavity 7. (See FIG. 1). Thereafter, the thermoplastic resin filled in the cavity 7 is cooled and solidified for a predetermined time. Then, the movable side mounting plate 3 is moved to open the fixed side mold 4 and the movable side mold 5, and the thermoplastic resin molded body H is removed from the movable side mold 5 using the ejector pins 16. Thereafter, a predetermined treatment is performed to complete a molded product as a product.

  The injection speed of the resin during molding, the temperature of the resin to be injected, and the temperature of the mold are not particularly limited, and may be appropriately controlled according to the size of the cavity, the resin material, and the like.

  According to the injection mold 1 described above, even when the plurality of grooves 20 on the cavity surface 19a extend in a direction substantially parallel to the flow direction of the thermoplastic resin, the injection mold is injected into the cavity 7 when the thermoplastic resin is injected. The flow of the resin is hardly affected. Furthermore, since the plurality of grooves 20 having a predetermined non-uniform configuration on the cavity surface 19a extend in a direction substantially parallel to the flow direction of the thermoplastic resin, the filling of the resin into the grooves 20 is promoted, and the cavity 7 is filled with The contact area between the injected molten thermoplastic resin and the metal plate 19 is increased. As a result, the cooling efficiency of the thermoplastic resin is improved in the portion of the cavity surface 19a where the plurality of grooves 20 are formed, so that occurrence of surface defects such as sink marks and dimples in this portion can be suppressed, and a good appearance can be achieved. It becomes possible to mold the thermoplastic resin molded body H.

  In the present specification, a depression formed on the surface of the molded product is referred to as a sink, and a circular recess in the sink is referred to as a dimple. Among thermoplastic resins, in particular, a crystalline thermoplastic resin such as polypropylene has a high thermal shrinkage rate and is likely to cause sink marks and dimples. In addition, there are cases where the surface tension is good because there are few sink marks and dimples in the molded product.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the above embodiment, a mold for forming the rectangular plate-shaped cavity 7 is adopted, but the present invention is not limited to this, and various types of articles such as flat plates, curved plates, and three-dimensional objects are injected. It can be applied to a mold for molding. In particular, it is particularly effective when the cavity is large, for example, when the distance from the resin gate to the end portion is 100 mm or more.

  Further, in the above-described embodiment, one gate G is provided for one cavity 7, but the present invention can also be applied to a mold having a plurality of gates G for one cavity. For example, as shown in FIG. 7, when gates G1 and G2 are provided on both sides of a rectangular plate-shaped cavity, the end E part of the flow of the thermoplastic resin is a substantially central part where the resin joins, Although sink marks and dimples are easily formed, the same effect as in the above embodiment can be obtained by forming the plurality of grooves 20 extending in a direction substantially parallel to the flow direction of the thermoplastic resin, for example, on the entire surface or only at the end portions. It is done.

  Further, in the above embodiment, the plurality of grooves 20 are formed on the non-design surface of the cavity, but if the surface quality of the molded product is not particularly required, a plurality of grooves may be formed on the design surface, It is more preferable to form a plurality of grooves on both the design surface and the non-design surface.

  Also, the injection method from the gate G is not particularly limited, and it may be a cold type or a hot runner type.

  Furthermore, the plurality of grooves 20 substantially parallel to the flow of the thermoplastic resin do not necessarily have to be provided at the end E of the flow of the thermoplastic resin. The present invention can be implemented even if it is selectively provided in a portion where it can be easily performed.

  Moreover, in the said embodiment, although the some groove | channel was provided in the metal plate provided in the shape plate, you may form the some groove | channel 20 directly in a type | mold, without using a metal plate.

Hereinafter, the present invention will be described in more detail with reference to examples of the cavity surface 19a of the metal plate 19 and comparative examples.
[Examples A1-1 to A1-4]

In Examples A1-1 to A1-4, FS160 (maximum pressure 1435 kgf / cm ² , maximum injection rate 195 cm ³ / s) manufactured by Nissei Plastic Industry Co., Ltd. was used as an injection molding machine. Aluminum is selected as the material of the metal plate 19, and the finished molded body has outer dimensions of 400mm in length, 100mm in width, and 2mm in thickness. The resin is injected from one gate at the center in the longitudinal direction toward the other end. An aluminum plate in which grooves in the direction parallel to the resin flow direction (MD direction) are formed on the entire surface of one cavity surface of the mold with the # 240 sandpaper (see FIG. 5A). ) And insert molding was performed. The injection molding conditions are as follows: the cylinder temperature of the injection molding machine is 220 ° C., the mold temperature is 40 ° C., the injection speed is 50% of the maximum injection speed, the resin weighing position is 89 mm, the suck back is 1 mm, The total pressure time was 15 seconds, the cooling time was 30 seconds, the back pressure was 10% of the maximum pressure, and the primary pressure was 60% of the maximum pressure. The time until VP switching was approximately 1.8 seconds. PP (polypropylene: AZ864E4 (MFR 30 g / 10 min, 230 ° C.): Sumitomo Chemical Co., Ltd.) was employed as the thermoplastic resin to be the molding material. Further, in Examples A1-1 to A1-4, the pressure holding and the VP switching were changed as shown in Table 1, respectively. Here, the holding pressure is the holding pressure after full filling with respect to the maximum pressure (1435 kgf / cm ² ) of the injection molding machine, and the VP switching is to switch the resin control in the injection device from speed control to pressure control. Timing, expressed by screw position in the injection device. And Example A1-1 was full filling (just pack), and Example A1-4 was underfilling (short shot).
[Comparative Examples A1-1 to A1-4]

Examples A1-1 to A1-4 were the same as those of Example A1-1 except that grooves were not formed on the entire surface of one cavity surface of the mold.
[Comparative Examples A2-1 to A2-4]

Examples A1-1 to A1- except that an aluminum plate in which grooves in a direction (TD direction) perpendicular to the resin flow direction (TD direction) were previously formed with # 240 sandpaper was used on the entire surface of one cavity surface of the mold. Same as 4 respectively.
[Examples B1-1 to B1-4]

A composite PP containing talc (polypropylene: containing 20 wt% talc, MFR 42 g / 10 min, 230 ° C.) is used as a thermoplastic resin as a molding material, and the holding pressure and VP switching are set as shown in Table 1, respectively. Except for this, the procedure was the same as in Examples A1-1 to A1-4.
[Comparative Examples B1-1 to B1-4]

The same procedure as in Examples B1-1 to B1-4 was conducted, except that no groove was formed on the entire surface of one cavity of the mold.
[Comparative Examples B2-1 to B2-4]

  Example B1-1 to Example B1-1 except that an aluminum plate in which grooves in the direction perpendicular to the resin flow direction (TD direction) were formed in advance by sandpaper of # 240 was used on the entire surface of one cavity surface of the mold. Each was the same as B1-4.

These results are shown in Table 1. The number of dimples shown in Table 1 is an average value of the number of dimples in a thermoplastic resin molded article that is injection-molded four times under each condition.

As shown in Table 1, the groove in the direction parallel to the resin flow (MD direction) is compared with the comparative example in which the groove in the direction perpendicular to the resin flow (TD direction) is formed. In the example formed on the surface 19a, the number of dimples in the thermoplastic molded body was significantly reduced. This result was noticeable even when the thermoplastic resin was changed from PP to composite PP. In Tables 1 to 3, “parallel grooves” means a plurality of grooves extending in a direction parallel to the resin flow direction, and “vertical grooves” extend in a direction perpendicular to the resin flow. Means a plurality of grooves.
[Example C1]

The finished molded body has a 400mm length, 100mm width and 2mm thickness mold, the cylinder temperature of the injection molding machine is 250 ° C, the resin weighing position is 90mm, the holding pressure is 0%, It was the same as Example B1-1 except that the VP switching was set to 25 mm and an aluminum plate with grooves formed in advance with # 120 sandpaper was used. The injection time was as shown in Table 2.
[Example C2]

The cavity surface was equally divided into two in the resin flow direction, and only the end side of the flow was a groove extending in the direction parallel to the flow (MD direction), and no groove was provided on the gate side (see FIG. 5B). ) Was the same as Example C1.
[Example C3]

The cavity surface is equally divided into two in the resin flow direction, the end side of the flow is a groove extending in the direction parallel to the flow (MD direction), and the gate side is a groove extending in the direction perpendicular to the flow (TD direction) (See FIG. 5 (c)).
[Comparative Example C1]

The procedure was the same as Example C1 except that no groove was provided on the cavity surface.
These results are shown in Table 2.

  In addition, the injection time in Table 2 is the time until the injection of one thermoplastic resin from the injection device.

As shown in Table 2, the number of dimples in Examples C1 to C3 having a plurality of grooves 20 parallel to the resin flow was smaller than that in Comparative Example C1 having no grooves on the cavity surface 19a. In addition, compared to Example C2 in which a plurality of grooves 20 parallel to the resin flow were formed only on the end E side of the flow of the cavity surface 19a, the number of dimples was further reduced in Example C1 formed over the entire surface. . Further, in Example C3 in which a plurality of grooves 21 perpendicular to the resin flow are provided on the gate G side of the cavity surface 19a, and a plurality of grooves 20 parallel to the resin flow are formed on the terminal E side of the resin flow, The number of dimples has decreased significantly.
[Example D1]

The finished molded body is 300mm long, 50mm wide and 2mm thick. Use a mold with gates G1 and G2 located at both ends, resin weighing position is 90mm, suck back is 2mm, injection Example B1-1 except that the total holding pressure is 10 seconds, holding pressure is 0%, VP switching is 25 mm (full filling), and resin is injected from both gates G1 and G2 (see FIG. 7). And the same. In addition, the metal mold | die with which the groove | channel (MD direction) of the direction parallel to the flow of resin was formed in the whole cavity surface (non-design surface) was used.
[Example D2]

V-P switching was set to 23.5 mm, and the same procedure as in Example D1 was performed except that the filling was not full but insufficient.
[Comparative Examples D1, D2]

Except for forming grooves in the direction perpendicular to the resin flow (TD direction) on the entire cavity surface (non-design surface), the same procedure as in Examples D1 and D2 was performed.
The results are shown in Table 3. In Example 3, the end of the thermoplastic resin flow is located near the center of the rectangular cavity surface equally divided in the length direction.

  As shown in Table 3, even when the gates G1 and G2 are provided at both ends, a plurality of parallel parallel to the resin flow is obtained as compared with Comparative Examples D1 and D2 in which a plurality of grooves perpendicular to the resin flow are formed. In Examples D1 and D2 in which the groove 20 was formed, the number of dimples was reduced. This result did not change with full or underfill.

It is sectional drawing which shows one Embodiment of the metal mold | die for injection molding which concerns on this invention. It is sectional drawing which shows the open state of the injection die shown in FIG. It is a perspective view which shows the fixed side type | mold shown in FIG. It is a perspective view which shows the movable side type | mold shown in FIG. It is a top view which shows an example of the movable side type metal plate shown in FIG. It is a schematic enlarged view which shows the surface shape of a metal plate. It is a top view which shows the other example of a movable-side type metal plate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Injection mold, 2 ... Fixed side mounting plate, 3 ... Movable side mounting plate, 4 ... Fixed side type | mold (1st type | mold), 5 ... Movable side type | mold (2nd type | mold), 7 ... Cavity, DESCRIPTION OF SYMBOLS 14 ... Gate shaping | molding part, 18, 19 ... Metal plate, 18a, 19a ... Cavity surface, 20 ... Groove, 21 ... Groove, E ... End of resin flow, G, G1, G2 ... Gate, H ... Thermoplastic resin molding body.

Claims (4)

First and second molds forming a cavity into which a thermoplastic resin is injected are provided, and the flow of the thermoplastic resin flowing into the cavity from a gate that is an inlet of the cavity is the thermoplastic resin in the cavity. An injection mold in which the thermoplastic resin is filled into the cavity by reaching the end of the flow of
At least one of the cavity surface of the first mold and the cavity surface of the second mold is formed with a plurality of grooves extending in a direction substantially parallel to the flow direction of the thermoplastic resin. An injection mold in which at least one of an interval between grooves, a depth of the plurality of grooves, and a width of the plurality of grooves is non-uniform.   The injection mold according to claim 1, wherein the plurality of grooves are formed on a terminal side of the flow of the thermoplastic resin in the cavity surface.   The injection according to claim 2, wherein a plurality of grooves extending in a direction substantially orthogonal to a flow direction of the thermoplastic resin are further formed on a gate side of the cavity surface in which the plurality of grooves are formed. Mold for molding. An injection step of injecting a molten thermoplastic resin into a cavity formed by the first and second molds;
A cooling step for cooling the molten thermoplastic resin injected into the cavity,
At least one of the cavity surface of the first mold and the cavity surface of the second mold is formed with a plurality of grooves extending in a direction substantially parallel to the flow direction of the thermoplastic resin. A method for producing a thermoplastic resin molded body, wherein at least one of a spacing between grooves, a depth of the plurality of grooves, and a width of the plurality of grooves is not uniform.

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