JP4508825B2 - Insert molding die, method of manufacturing insert molded product, and insert molded product - Google Patents

Description

  The present invention relates to an insert molding die, a method for manufacturing an insert molded product, and an insert molded product, and more particularly, an insert for manufacturing an insert molded product by an insert molding method (transfer molding method, film integral molding method) by injection molding. The present invention relates to a structure of a molding die, a method for manufacturing an insert molded product using the insert molding die, and an insert molded product manufactured by the manufacturing method.

An insert molding method is known in which an insert film is placed on the cavity surface of a mold and injection molding is performed to form a pattern including characters and symbols on the surface of the molded product simultaneously with the injection molding. In general, in the transfer molding method and the film integral molding method in the insert molding method, a transfer film having a layer on which a foil thin film or pattern is formed and a release layer, or a film integral having a layer on which a foil thin film or pattern is formed With the molded film placed along the mold set lower than the thermal deformation temperature of the thermoplastic resin to be injected, the molten resin is injected into the mold cavity to mold the resin molded product and transfer A pattern such as a thin film or a pattern of a film or an integrally formed film is formed on the surface of the molded product (see, for example, Patent Document 1).
JP 2001-191362 A

  In the transfer molding method and the film integral molding method as described above, since the molten resin is injected into the cavity with the mold temperature set lower than the thermal deformation temperature of the thermoplastic resin, molding having a predetermined pattern in a high cycle. It is possible to obtain goods. However, when the molded product has a hole shape such as a through hole (through hole or opening), or when the product size is large and many resin injection ports are required, the mold temperature is low. A weld line is generated at a portion where the molten resin flows in the cavity, and the appearance of the molded product as a product is significantly impaired.

  For this reason, when manufacturing products with a hole shape, such as household electrical appliances and household goods, in order to prevent the formation of weld lines, molding without a hole shape is required. After the product is insert-molded, the molded product is drilled (trimmed) to obtain a product having a hole shape of a predetermined size at a predetermined position. Therefore, the manufacturing process increases, which is a factor that increases the manufacturing cost. On the other hand, when the product size is large, the position of the resin injection port is set so that the weld line is generated at a position where the product is not conspicuous, but this also has a limit.

  Accordingly, the present invention provides an insert mold that can reliably prevent the occurrence of weld lines in an insert molded product, and can efficiently manufacture a molded product having a hole shape or a large molded product, and the insert mold. It is an object of the present invention to provide a method of manufacturing an insert molded product used and an insert molded product manufactured by the manufacturing method.

In order to achieve the above object, an insert mold according to the present invention has an insert film disposed along at least one cavity surface of a cavity formed by clamping a fixed mold having a resin injection port and a movable mold. In a mold for molding a resin molded product by injecting a molten thermoplastic resin into the cavity and transferring a pattern from the insert film to the surface of the molded product, a position where a weld line is generated at the time of injection molding At least one of the corresponding fixed mold and movable mold is formed with a recess opening on the side opposite to the cavity surface, and a heating medium for heating the cavity surface in a nest mounted in the recess and for cooling The temperature control passage to which the cooling medium is supplied is provided, and the nesting portion except the cavity surface side is provided.
An air layer serving as a heat insulating portion is provided between the side surface and the wall surface of the concave portion .

  Moreover, the manufacturing method of the insert molded product of the present invention is a method of manufacturing an insert molded product using the insert molding die having the above structure, and when injecting resin into the cavity where the insert film is disposed, The heating medium is supplied to the temperature control passage to heat the cavity surface to a temperature higher than the thermal deformation temperature of the thermoplastic resin to be injected, and after the injection is finished, the cooling medium is supplied to the temperature control passage to Is cooled to a temperature lower than the thermal deformation temperature.

  Furthermore, the insert-molded product of the present invention is an insert-molded product that has been insert-molded by the above manufacturing method, and is an insert product that has a high-quality appearance.

According to the present invention, a part of the key Yabiti surface, for example, the temperature regulating passage provided near the cavity surface to correspond to the occurrence position of the weld line, a heating medium and cooling medium of a predetermined temperature to the temperature regulating passage By supplying and heating and cooling the cavity surface to a predetermined temperature, the generation of weld lines can be prevented. Furthermore, by providing a heat insulating part around the temperature control passage excluding the cavity surface side, heat loss during heating / cooling can be suppressed, and a predetermined cavity surface can be formed in a short time with a small amount of heating medium and cooling medium. Heating and cooling can be performed efficiently. In addition, the temperature control passage for partial heating may be provided in correspondence with the position where the weld line, etc., obtained by the resin flow analysis is generated, so piping for heating / cooling medium supply / discharge is simple. It is easy to adapt to the movable mold and does not adversely affect the operation of the movable mold or the removal of the molded product. As a result, an insert product having no weld line and having a high quality appearance can be obtained.

1 and 2 show a first reference example of an insert molding die according to the present invention. FIG. 1 is a cross-sectional view, and FIG. 2 is a front view of the stationary die as viewed from the cavity side. The insert mold shown in this embodiment is an example of a two-piece mold, but only one is shown and the other is omitted.

  This insert molding die has a movable die 11 and a fixed die 12, and the fixed die 12 incorporates an insert 14 having a cavity 13 for molding a thin plate-like molded product. The cavity 13 is provided with a plurality of hole shape forming portions 15 for forming hole shape portions of the product at predetermined positions, and a resin injection port (gate) for injecting molten resin into the cavity 13 at one end. ) 16 is provided. The movable mold 11 and the fixed mold 12 are provided with vacuum suction holes (not shown) for fixing the insert films 17 and 17 at predetermined positions, positioning fixing pins, and the like at predetermined positions.

  Furthermore, the movable mold 11 and the fixed mold 12 are fixed to the base plate via a heat insulating material 18 like a general injection mold, and the sprue 19 to which the molten resin is supplied is supplied to the fixed mold 12. The runner 20 and the gate 16 are provided, and the movable die 11 is provided with an ejector pin for taking out a molded product.

  And inside the movable mold | type 11 and the fixed mold | type 12, the temperature control paths 21 and 22 for heating and cooling a cavity surface to predetermined temperature are provided in the position close | similar to a cavity surface. The temperature control passages 21 and 22 are supplied with a heating medium for heating the cavity surface to a predetermined temperature, and with a cooling medium for cooling the cavity surface in a temperature-up state to a predetermined temperature. The temperature control passage 22 of the fixed mold 12 is formed by forming a groove on the side opposite to the cavity of the insert 14 and covering the opening of this groove with a temperature control passage cover 22b via a seal material 22a. In the mold 11, a through hole serving as the temperature adjustment passage 21 is formed directly in the mold.

  Further, the nest 14 is fixed to the fixed mold main body part via the heat insulating material 23 on the side opposite to the cavity, and a gap is formed between the fixed mold main body part on both side portions to form an air layer 24 serving as a heat insulating part. Like to do. In this way, by providing a heat insulating portion such as the heat insulating material 23 and the air layer 24 around the temperature control passage 21, the heating medium and the cooling medium are supplied to the temperature control passage 21 to heat and cool the cavity surface. In addition, heat energy during heating / cooling can be prevented from being transmitted to the mold part excluding the cavity surface, and the heat energy loss of the heating medium and cooling medium can be suppressed and used effectively. A specific cavity surface can be effectively heated and cooled with a small amount of heating medium or cooling medium.

FIG. 3 is a cross-sectional view of the main part showing a first embodiment in the mold structure of the insert molding mold of the present invention. In this embodiment, in a movable mold or a fixed mold (hereinafter simply referred to as a mold 31), a temperature adjustment passage 33 is provided at a position close to the cavity surface 32 corresponding to a position where a weld line is generated during injection molding. The temperature control passage 33 is provided in a nest 35 that is mounted in a recess 34 that is open on the opposite side of the mold 31 to the cavity side. The tip surface 35a on the cavity surface side of the insert 35 is in close contact with the bottom wall 34a of the recess 34, and between the side surface 35b of the insert 35 and the wall surface 34b of the recess 34, there is a heat insulating portion. An air layer 36 is provided.

  In this way, by providing the temperature adjustment passage 33 so as to heat and cool only a part of the cavity surface 32 corresponding to the place where the weld line is generated without providing the temperature adjustment passage in the entire mold 31, Compared with the case where the temperature control passage is provided in the entire mold 31, the number of pipes and the like is reduced, and an increase in peripheral devices of the mold 31 can be minimized. In addition, the code | symbol 37 is a heat insulating material provided between baseplates.

FIG. 4 is a cross-sectional view of the main part showing a second embodiment of the insert molding die of the present invention. In the following description, the same components as those in the mold structure shown in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, a concave groove 35 c is provided on the distal end surface 35 a on the cavity surface side of the insert 35 that is mounted in the concave portion 34 opened on the opposite side of the mold 31 to the cavity side, and the distal end surface 35 a is used as the bottom wall of the concave portion 34. The temperature control passage 33 is formed in a portion surrounded by the concave groove 35c and the bottom wall 34a by being in close contact with 34a. Further, a sealing material 38 for preventing the leakage of the heating medium and the cooling medium is provided around the temperature adjustment passage 33, and between the side surface 35 b of the insert 35 and the wall surface 34 b of the recess 34, An air layer 36 serving as a heat insulating portion is provided. By forming in this way, the cavity surface 32 can be efficiently heated and cooled in the same manner as described above.

FIG. 5 is a cross-sectional view of a main part showing a second reference example of the insert molding die of the present invention. In this embodiment, one row or a plurality of through-holes serving as the temperature control passage 33 are formed in the mold 31 and an air layer serving as a heat insulating portion is formed around the temperature control passage 33. A groove 39 is provided. As described above, the same effect as described above can be obtained by directly forming the temperature adjusting passage 33 in the mold 31.

FIG. 6 is a cross-sectional view of the main part showing a third embodiment of the insert molding die of the present invention. This embodiment shows an example in which a reinforcing member 40 made of a low thermal conductivity metal is provided on the base plate side of the insert 35 attached to the recess 34 of the mold 31 instead of the heat insulating material. As described above, the reinforcing member 40 is provided on the base plate side of the insert 35, or the base plate side of the base plate side of the insert 35 or the portion provided with the through hole serving as the temperature adjusting passage 33 shown in the fourth embodiment is used as the base plate. By extending so as to be in contact with each other, the mounting portion of the insert 35 and the portion provided with the temperature adjustment passage 33 can be reinforced, and the overall strength of the mold 31 can be ensured.

In addition, the temperature control path in the mold structure shown in each embodiment and each reference example may be provided in one of the movable mold 11 and the fixed mold 12, or may be provided in both. In addition, the shape of the temperature control passage and the like can be appropriately set according to various conditions such as the position and area of the cavity surface to be heated and cooled, the size of the mold, the heating temperature and the cooling rate. Moreover, in each form example, although an air layer is provided as a heat insulation part, you may fill this part with a heat insulating material.

  Furthermore, the insert film 17 may be disposed on either the movable mold 11 or the fixed mold 12. The insert film 17 may be a long shape that can be continuously formed, but may have a predetermined shape. It may be formed by a batch method after being cut into pieces. In addition, the detailed structure of the mold can be formed in the same manner as conventionally used injection molds, and is appropriate depending on conditions such as the shape of the molded product and the type of thermoplastic resin used. A structure can be adopted.

  When an insert molded product is manufactured using the insert molding die formed as described above, as shown in FIG. 1, each insert film 17 on which a predetermined foil thin film or pattern is formed is fixed to the movable mold 11 and fixed. The mold 12 is arranged and fixed at a predetermined position and clamped, and a heating medium is supplied to the temperature control passages 21 and 22 to heat the mold temperature, that is, the temperature of the cavity surface to a temperature higher than the thermal deformation temperature of the thermoplastic resin. To do. In this state, molten resin is injected from the gate 16 into the cavity 13 to mold a resin molded product, and a pattern is transferred from the insert film 17 to the surface of the molded product. After the injection is completed, a cooling medium is supplied to the temperature adjusting passages 21 and 22 to cool the temperature of the cavity surface to a temperature lower than the thermal deformation temperature.

  In this way, by heating the cavity surface where the weld line is likely to occur in the molded product to a temperature higher than the thermal deformation temperature of the thermoplastic resin during injection molding, the fluidity of the resin is increased and the occurrence of weld lines is prevented. can do. Moreover, since the molding cycle can be shortened by cooling the cavity surface immediately after injection molding, the production efficiency can be greatly improved. In particular, since only the portion where the weld line is generated due to the hole shape or the like is heated and cooled, it can be efficiently heated and cooled in a short time with a small amount of heating medium and cooling medium.

  The insert-molded product obtained in this way has a high-quality appearance with no poor appearance due to the weld line, even if it has a hole shape or a large size, and is a transparent resin such as polycarbonate. Even in this case, it is excellent in transparency, has a good appearance, and is a high-quality molded product. Therefore, it is optimal for products that require high-quality aesthetics, such as household electrical appliances and household goods.

It is sectional drawing which shows the 1st reference example of the insert molding die of this invention. It is the front view which similarly looked at the stationary mold from the cavity side. It is sectional drawing of the principal part which shows the 1st form example in the metal mold | die structure of the insert molding metal mold | die of this invention. It is sectional drawing of the principal part which shows the 2nd example of an insert mold of this invention. It is sectional drawing of the principal part which shows the 2nd reference example of the insert molding die of this invention. It is sectional drawing of the principal part which shows the 3rd form example of the insert molding die of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Movable type | mold, 12 ... Fixed type | mold, 13 ... Cavity, 14 ... Nesting, 15 ... Hole shape formation part, 16 ... Gate, 17 ... Insert film, 18 ... Thermal insulation, 19 ... Sprue, 20 ... Runner, 21, 22 ... Temperature control passage, 22a ... Sealing material, 22b ... Temperature control passage cover, 23 ... Heat insulation material, 24 ... Air layer, 31 ... Mold, 32 ... Cavity surface, 33 ... Temperature control passage, 34 ... Recess, 34a ... Bottom wall, 34b ... wall surface, 35 ... nesting, 35a ... tip surface, 35b ... side surface, 35c ... concave groove, 36 ... air layer, 37 ... heat insulating material, 38 ... sealing material, 39 ... groove, 40 ... reinforcing material

Claims (3)

An insert film is disposed along at least one cavity surface of a cavity formed by clamping a fixed mold having a resin injection port and a movable mold, and a molten thermoplastic resin is injected into the cavity to form a resin. In an insert molding die for molding a product and transferring a pattern from the insert film to the surface of the molded product , an anti-cavity surface is provided on at least one of the fixed die and the movable die corresponding to a position where a weld line is generated during injection molding. to form a recess that opens to the side, provided with a temperature control passage cooling medium is supplied in the heating medium and for cooling for heating the cavity surface insert which is mounted in the recess, cavity side insert molding die, characterized in that is provided an air layer as a heat insulating portion between the side surface and the recess of the wall of the entering element except .   A method for manufacturing an insert molded product using the insert molding die according to claim 1, wherein when a resin is injected into a cavity in which the insert film is disposed, a heating medium is supplied to the temperature control passage. The temperature of the cavity surface is heated to a temperature higher than the heat deformation temperature of the thermoplastic resin to be injected, and after the injection is finished, a cooling medium is supplied to the temperature adjusting passage to lower the temperature of the cavity surface to a temperature lower than the heat deformation temperature. A method for producing an insert-molded product, characterized by cooling.   An insert-molded product, which is insert-molded by the manufacturing method according to claim 2.

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