JP2014034173A - Method for manufacturing a resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a resin molding capable of preheating a primary molding simply and locally, visually recognizing, even if a defect exists on a molten resin injection site, the defect easily, and inhibiting the enlargement of the resin molding.SOLUTION: The provided resin molding manufacturing method for manufacturing a resin molding 15 arranges a primary molding 1 within molds 6 and 7, introduces a molten resin 5 into the molds 6 and 7, and produces a resin molding 15 by then executing a secondary work. An introduction flow path 4 surrounded by the primary molding 1 and molds 6 and 7 is formed in a state where the primary molding 1 is being arranged within the molds 6 and 7, and after the junction interface of the primary molding 1 has been heated by pumping a heating fluid into the introduction flow path 4, a secondary work is executed by introducing the molten resin 5 into the introduction flow path 4 and then joining the same with the primary molding 1.

Description

  The present invention relates to a method for manufacturing a resin molded body, which performs a secondary process on a primary molded body to manufacture a resin molded body.

  Conventionally, secondary processing has been performed by joining a molten resin to a primary molded body such as insert molding or two-color molding. In this case, the entire mold may be heated with a heat medium or a heater in order to increase the bonding strength of the joint or improve the appearance. According to this manufacturing method, the primary molded body may be well adapted to the molten resin, and the adhesiveness and appearance of the joint may be improved.

  However, if the method of heating the entire mold in this way is adopted, a special heating device is attached to the manufacturing facility, or the primary molded body contracts due to heating or the quality is impaired due to deformation. There were economic and quality problems.

  As another method for producing a resin molded body, Patent Document 1 provides a flow path capable of flowing water vapor or water at a position close to the surface of a mold, and heats water only when heating is required. On the other hand, a method of performing resin molding while repeating heating and cooling by always flowing cooling water to a position far from the mold surface is disclosed. However, such a manufacturing method requires a very expensive mold and generates water vapor, which is a problem because it becomes a large-scale apparatus.

  As another method for producing a resin molded body, Patent Document 2 discloses a mold in which warm air and a cold air circuit are provided in addition to a hot water and a cold water circuit to greatly increase the efficiency of heating and cooling. . However, the mold structure has become more and more complicated, and the equipment cost has been a problem.

  The mold heating and cooling system as in Patent Documents 1 and 2 is that the entire mold is maintained at a uniform temperature, and that the temperature conditions such as heating to cooling or cooling to heating are changed in a short time. Although it is extremely excellent, it is difficult to cope with local heating such as insert molding and two-color molding using a primary molded body, and it is particularly easy to heat only the resin joint when performing secondary processing. I couldn't.

  In order to deal with these problems, in Patent Document 3, as shown in FIGS. 6 and 7, each member 51, 52 of a primary molded body 50 composed of a plurality of members 51, 52 formed in a separate process is disclosed. In a method of joining members by secondary molding, a tubular passage 53 is formed in a joint portion where the members 51 and 52 are attached to each other, and a heating medium such as heated air is fed into the tubular passage 53 to form a primary compact 50. The joints (of the members 51 and 52) are heated, and thereafter, the molten resin as the secondary resin is injected into the tubular passage 53 to join the members 51 and 52 forming the primary molded body 50 together. Have been described.

  According to this manufacturing method, it is only necessary to provide a device for feeding a heating medium such as heated air into the tubular passage 53, so that an increase in manufacturing cost can be suppressed to a relatively small amount. Moreover, since the part heated with heating media, such as heating air, is restricted to the tubular channel | path 53 and its vicinity part, the members 51 and 52 which comprise the primary molded object 50 may shrink | contract or a quality may be impaired by deformation | transformation. Can be kept to a minimum and good quality can be maintained.

Japanese Patent Laid-Open No. 11-348041 JP 2009-233980 A Japanese Patent No. 4281332

  However, in the method of manufacturing a resin molded body according to Patent Document 3, since the tubular passage 53 into which the molten resin is injected is surrounded by the members 51 and 52 forming the primary molded body 50, the molten resin injection location is defective. Even if there is a part, there is a problem that it cannot be visually recognized and lacks reliability. Moreover, the location which joins the members 51 and 52 which comprise the primary molded object 50 requires the tubular channel | path 53 and the junction parts 51a, 51b, 52a, 52b of the members 51 and 52 of the both sides, The width H1 of the tubular passage 53, the width H2 of the joint portions 51a and 52a of the members 51 and 52, and the width H3 of the joint portions 51b and 51b of the members 51 and 52 are combined as a width H4 ( = H1 + H2 + H3) is required, and as a result, there is a problem that the produced resin molded body is enlarged.

  The present invention solves the above-mentioned problems, and can easily and locally preheat the primary molded body, and even if there is a defective portion in the molten resin injection site, it can be easily visually confirmed. Another object of the present invention is to provide a method for producing a resin molded body that can prevent the resin molded body from becoming large.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to solve the above problems. That is, the gist of the present invention is as follows.

  The present invention is a method of manufacturing a resin molded body in which a primary molded body is disposed in a mold, a molten resin is introduced into the mold and secondary processing is performed to manufacture a resin molded body. Forming a flow path for introduction surrounded by the primary molded body and the mold in a state where the body is disposed in the mold, and feeding a heating fluid into the flow path for introduction, thereby joining the joint portion of the primary molded body It heats and after this, secondary processing is performed by introduce | transducing molten resin into the said introduction flow path, and joining a primary molded object, It is characterized by the above-mentioned.

  Further, in the present invention, the primary molded body is composed of a plurality of members, and the members are disposed in the mold so that the members face the introduction flow path, and the heating fluid is fed into the introduction flow path. It heats the junction part of the members of a primary molded object, and introduce | transduces molten resin into the flow path for introduction after this, and performs secondary processing by joining members.

  Further, as a method of heating the joined portion of the primary molded body by feeding a heated fluid into the introduction flow path of the present invention, the primary molded body is introduced by introducing the heated fluid into the introduction flow path. The joint portion of the primary molded body is heated by the gas that has been compressed or introduced into the introduction flow path while being compressed, and is compressed to a high temperature.

  In addition, as a primary molded object, the hollow molded object which consists of a some member may be sufficient. In addition, an electrical component such as a circuit board or a sensor component may be enclosed in a primary molded body made of a hollow molded body.

  According to the present invention, since the joined portion of the primary molded body is heated by feeding the heating fluid into the introduction flow path, only the joint portion of the primary molded body can be easily preheated locally. The primary molded body can be kept in good quality without shrinking or being damaged by the deformation. In addition, the introduction flow path for introducing the molten resin is formed so as to be surrounded by the primary molded body and the mold in a state where the primary molded body is disposed in the mold. If there is a defective portion at the location, the defective portion is easily exposed on the outer surface and can be easily visually recognized. In addition, the introduction flow path into which the molten resin is introduced does not have to be completely covered with the primary molded body, and it is only necessary to face the portion to be joined (facing), thus forming the primary molded body. It is possible to reduce the width of the portion where the members are joined, and as a result, it is possible to reduce the size (compact) of the manufactured resin molded body.

It is a longitudinal cross-sectional view which shows the state which manufactures the resin molding by the manufacturing method of the resin molding which concerns on embodiment of this invention. It is a principal part expanded sectional view which shows the state which has manufactured the resin molding by the manufacturing method of the same resin molding (however, the state before introduce | transducing molten resin is shown). In the manufacturing method of the resin molding, it is a plane sectional view showing the state where heated air (heating gas) is sent. In the manufacturing method of the same resin molding, it is a plane sectional view showing the state where molten resin is introduced. It is a longitudinal cross-sectional view which shows the state which has manufactured the resin molding by the manufacturing method of the resin molding which concerns on other embodiment of this invention. It is sectional drawing which shows the state which has manufactured the resin molding by the manufacturing method of the conventional resin molding. It is a principal part expanded sectional view which shows the state which has manufactured the resin molding by the manufacturing method of the conventional resin molding.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 4, the method for producing a resin molded body of the present invention is schematically arranged in such a manner that the primary molded body 1 is disposed in the molds 6 and 7 and melted in the molds 6 and 7. This is a method for manufacturing a resin molded body in which a resin molded body 15 is manufactured by introducing a resin 5 and performing secondary processing. Then, in a state where the primary molded body 1 is disposed in the molds 6 and 7, the introduction flow path 4 surrounded by the primary molded body 1 and the molds 6 and 7 is formed. The joints 2b and 3b of the primary molded body 1 are heated (preliminary heating) by feeding heated gas such as heated air (heating fluid), and then the molten resin 5 is introduced into the introduction flow path 4 to perform primary molding. Secondary processing is performed by joining the body 1.

  The said primary molded object 1 is a molded object shape | molded using resin, and there is no limitation in a shape, thickness, etc. For example, when the resin molded body 15 is a box-shaped resin molded body 15 as shown in FIG. 1, a first member 2 corresponding to a box body portion molded in advance and a second member corresponding to a lid portion. The primary molded body 1 is constituted by the member 3. On the other hand, as shown in FIGS. 1 and 2, the secondary processing means that the first member 2 and the second member 3 are fitted to each other, and the introduction flow provided in the vicinity of the fitting portions 2a and 3a. The molten resin 5 is introduced (introduced) into the path 4, and the first member 2 and the second member 3 are completely joined by the molten resin 5. FIG. 1 shows a case where the primary molded body 1 is a hollow molded body and an electrical component (including electronic components) 10 such as a circuit board or a sensor component is enclosed in the primary molded body 1. Yes.

  Here, the introduction flow path 4 into which the molten resin 5 is introduced is surrounded by the first and second members 2 and 3 as the primary molded body 1 and the dies 6 and 7 as shown in FIG. Is formed. That is, as shown in FIG. 2 in an enlarged manner, the introduction flow path 4 into which the molten resin 5 is introduced includes the joining portion 2b of the first member 2, the joining portion 3b of the second member 3, and the mold. 6 and 7 are surrounded by the contact surface portions 6a and 7a.

  As the resin used for molding the primary molded body 1, that is, the resin used as the material of the first member 2 and the second member 3, polyamide (PA), ABS resin, polyester, polyvinyl chloride (PVC), Examples of the thermoplastic resin include polycarbonate (PC), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyarylate (PAR), polyether ether ketone (PEK), liquid crystal polymer (LCP), and fluororesin. They may be a single resin or a mixture of a plurality of resins. As a mixing method, there are a method of injection molding by mixing resin pellets of different materials at the time of molding, a method of injection molding using resin pellets obtained after melt-kneading resins of different materials, etc. Can be mentioned. The resin can be properly used depending on the application, such as crystalline resin or amorphous resin. For example, crystalline resin is used for applications that require heat resistance, and amorphous resin is used for applications that require transparency. Can be used. The first and second members 2 and 3 may be the same type or different types of resins. The molten resin 5 may be the same type as the first and second members 2 and 3 or may be a different type of resin. The combination of the resin constituting the first and second members 2 and 3 and the type of the molten resin 5 can be used in various combinations in consideration of the application, the adhesive strength at the time of joining, and the like. As a combination of the primary molded body 1 and the molten resin 5, PBT-PBT, PBT-PC, PBT-PVC, PBT-PET, PBT-PAR, PA6-PA6, PA66-PA66, PA9T-PA9T, PPS-PPS, LCP -LCP is exemplified.

The molds 6 and 7 used in the method for manufacturing the resin molded body 15 according to the embodiment of the present invention have a structure capable of performing preheating. As shown in FIG. 1 and the like, the heated gas and the molten resin 5 are used. Are introduced into the introduction flow path 4, communicated with the introduction flow path 4, the resin introduction flow path 13 for introducing the molten resin 5 into the molds 6, 7, and the introduction flow path 4 described later. A gas introduction flow path 8 and a gas discharge flow path 9 for introducing and discharging the heated gas are formed. And as a method of heating the primary compact 1 locally, a method of flowing a heat medium or heated gas (heating air) locally or a method of locally heating and embedding a heater can be considered. In this embodiment, in order to simplify the structure of the molds 6 and 7, a method of flowing heated gas such as heated air is used. In the embodiment shown in FIG. 1, the mold 6 is a fixed mold that is fixed, and the mold 7 is a movable mold that can be raised and lowered. However, the present invention is not limited to this embodiment.
In addition, although it does not specifically limit as a method to manufacture heated air, The method of heating gas through a heater and the method of taking in the waste heat of a heater and a molding machine and heating can be mentioned.

  As a structure for flowing heated gas such as heated air, a gas introduction flow path 8 communicating from the outside of the molds 6 and 7 to the introduction flow path (gap part) 4 in the molds 6 and 7 forming the resin is provided. Provide. In addition, a gas discharge channel 9 that communicates with the introduction channel 4 and exhausts gas is also provided. A structure that can be opened and closed is provided at the channel opening to the introduction channel 4 formed in the gap of the molds 6 and 7. In FIG. 1, a first elevating piston 11 as first opening / closing means that opens and closes a boundary portion between the introduction flow path 4 and the gas introduction flow path 8, and the introduction flow path 4 and the gas discharge flow path 9. And a second lifting / lowering piston 12 serving as a second opening / closing means for lifting / lowering the boundary between the first and second lifting / lowering pistons 11, 12. A path switching device is configured. In addition, 14 in FIG. 1 is a hot air generator (heated gas generator).

  Before the molten resin (secondary resin) 5 is introduced and molded, the first and second elevating pistons 11 and 12 are lowered, and the gas inlet of the gas introduction passage 8 and the gas discharge of the gas discharge passage 9 are discharged. The outlet is opened and air or gas heated from the outside flows into the molds 6 and 7 (introduction channel 4) (see FIG. 3). Thereafter, the heated gas passes through the joint portions 2b and 3b of the primary molded body 1 (first and second members 2 and 3) that are in contact with the molten resin 5 and the contact surface portions 6a and 7a of the dies 6 and 7. The gas is discharged from the gas discharge passage 9. When the surface portion of the primary molded body 1, that is, the joint portions 2 b and 3 b of the first and second members 2 and 3 are heated by the heated gas, the first and second elevating pistons 11 and 12 are raised, and the gas The gas inlet of the introduction channel 8 and the gas outlet of the gas discharge channel 9 are closed. After that, the molten resin 5 as the secondary molding resin is filled, and the molten resin 5 is brought into contact with the joint portions 2b and 3b of the first and second members 2 and 3 which are the surfaces of the primary molded body 1 heated with gas. Thus, the molten resin 5 is firmly welded to the bonding resin obtained by solidification (see FIG. 4).

  Further, as shown in FIG. 5, the heated gas may be pressurized when flowing the heated gas into the molds 6 and 7. Then, before the molten resin 5 is introduced, air or gas heated from the outside is compressed and filled into the dies 6 and 7 while being pressurized. Or pressurization compression filling is repeated by reciprocation. Thereby, the surface (joint part 2b, 3b of the 1st, 2nd members 2 and 3) of the primary molded object 1 which contacts the molten resin 5 which is a secondary molded product is heated by adiabatic compression of gas. If heated, the 1st raising / lowering piston 11 will be raised and the gas filling port of the gas discharge flow path 9 will be closed. Thereafter, the molten resin 5 is filled and brought into contact with the surface of the primary molded body 1 heated by the adiabatic compression of the gas (the joined portions 2b and 3b of the first and second members 2 and 3). Is firmly welded to the solidified bonding resin.

  In this way, a structure is adopted in which normal temperature gas or heated gas is compressed and heated to a high temperature (for example, a temperature close to the temperature at which the joint portions 2b and 3b of the first and second members 2 and 3 are melted). By doing this, there is an advantage that processing can be performed in a shorter time and with less energy than a structure in which heated air flows. Note that these methods may be mixed, and a gas (such as air) heated to a certain temperature may be further compressed and heated to a higher temperature. Although not shown in FIGS. 1, 5, etc., a third retracting / retracting piston that retreats to / from a boundary portion between the resin introducing flow path 13 for introducing the molten resin 5 and the introducing flow path 4 as necessary. An opening / closing means such as the above may be provided so that the gas is not discharged to the resin introduction flow path 13 side at the time of pressurization and compression filling or when the heated gas is introduced.

  The method for manufacturing the resin molded body 15 according to the embodiment of the present invention will be described more specifically. In the present embodiment, an injection molding method can be preferably used. In the molds 6 and 7 used in injection molding, the primary molded body 1 is held (arranged) in the molds 6 and 7. As shown in FIGS. 1 and 2, when the primary molded body 1 is composed of a plurality of members (first and second members 2 and 3), the members (first and second members 2 and 3) are formed. Are held in the molds 6 and 7 after fitting. When incorporating the electrical component 10 such as a circuit board or a sensor component into the primary molded body 1 (first and second members 2 and 3), the assembly of the electrical component 10 is completed in advance before the member (first and second members 1 and 2). The second members 2, 3) are fitted and held in the dies 6, 7 as the primary molded body 1. In the vicinity of the fitting portions 2a and 3a of the primary molded body 1, an introduction flow path 4 for introducing heated air (heated gas) from the inside of the molds 6 and 7 in advance is connected to the joint portions 2b and 3b of the primary molded body 1 and the metal mold. The molds 6 and 7 are formed so as to be surrounded by the contact surface portions 6a and 7a. Then, before the molds 6 and 7 are closed and the molten resin 5 is introduced, heated air is blown into the introduction flow path 4, and the joint portion 2 b near the fitting portions 2 a and 3 a of the primary molded body 1. 3b can be preheated. The temperature of the heated air can be appropriately adjusted depending on the type of resin constituting the primary molded body 1, the type of the molten resin 5, and the assumed bonding strength of the bonding portions 2 b and 3 b. The time for preheating the primary molded body 1 using heated air is appropriately determined depending on the temperature of the heated air and the temperature at which the temperature near the surface of the primary molded body 1 is set to preheat the primary molded body 1. Can be adjusted.

  For example, when the resin material of the primary molded body 1 is polycarbonate and a molded body having a thickness of 3 mm, and the molten resin 5 is polybutylene terephthalate, the temperature of the heated air is 250 ° C. The heating time is set to 10 seconds, the molten resin 5 made of polybutylene terephthalate is heated and melted at a cylinder temperature of 250 ° C., and injection molding is performed at a temperature of 60 ° C. of the molds 6 and 7. The resin molding 15 excellent in the joining strength of the joining portions 2b and 3b) of the first and second members 2 and 3 can be obtained.

  In the molding method, when using compressed heated air in which the pressure in the molds 6 and 7 is increased to 1 MPa using an electric cylinder, the temperature of the heated air is 300 ° C. and preheating using heated air The time is 5 seconds, and polybutylene terephthalate is heated and melted at a cylinder temperature of 250 ° C., and injection molding is performed at a temperature of 50 ° C. of the molds 6 and 7, thereby joining the joints (first and second) of the primary molded body 1. The resin molding 15 excellent in the joining strength of the joining portions 2b and 3b) of the members 2 and 3 can be obtained.

  The preheating conditions can be adjusted as appropriate, but in order to achieve efficient production of the resin molded body 15 and economically advantageous production by reducing energy when the resin molded body 15 is produced. The temperature of the heated air is preferably 50 to 400 ° C., the preheating time using the heated air is 1 to 30 seconds, and the pressurizing pressure is preferably 0.05 to 5 MPa.

  In the method of manufacturing the resin molded body 15 according to the present embodiment, the conditions change depending on the mold temperature before preheating or the ambient environmental temperature, and it becomes difficult to manufacture a stable resin molded body 15. Therefore, in order to stabilize the environmental temperature or the mold temperature itself by continuous operation, it is preferable to control the mold temperature in the range of 10 to 160 ° C. The mold temperature can be controlled using an environmental temperature control or an existing mold temperature control system.

  The method of manufacturing the resin molded body 15 according to the embodiment of the present invention includes the hollow primary molded body 1, the primary molded body 1 in which an electrical component 10 such as a circuit board or a sensor component is incorporated, and a circuit board. It can also be applied to a primary molded body in which electric parts such as sensor parts and the like are incorporated and resin is directly filled in these parts to produce a resin molded body having no space.

  The resin molded body 15 obtained in the present invention is suitable in the electric and electronic parts field because the bonding strength of the bonded portions (bonded portions 2b and 3b) of the primary molded body 1 is improved and the appearance of the bonded portions is improved. Can be used.

  Specific applications to which the resin molded body 15 can be applied include electric devices such as photoelectric sensors, temperature sensors, IC tags, waterproof fluorescent lighting devices, waterproof LED lighting devices, and waterproof electrical measuring devices. These electrical devices have strong joint strength, so that water and air can be prevented from entering, and electrical components such as circuit boards and sensor components can be protected over a long period of time. Durability and long-term reliability are improved.

  In addition, according to the present invention, since the joined portions 2b and 3b of the primary molded body 1 are heated by feeding heated gas into the introduction flow path 4, only the joined portions 2b and 3b of the primary molded body 1 are simply and easily provided. Can be preheated locally, and the primary molded body 1 can be kept in good quality without shrinking or being damaged by deformation. In addition, the introduction flow path into which the molten resin 5 is introduced is formed so as to be surrounded by the primary molded body 1 and the molds 6 and 7 in a state where the primary molded body 1 is disposed in the molds 6 and 7. Therefore, if there is a defective portion at the injection site of the molten resin, the defective portion is easily exposed to the outer surface and can be easily visually recognized. Further, the introduction flow path 4 into which the molten resin is introduced does not have to be completely covered by the primary molded body 1 and only the portions to be joined (joining portions 2b and 3b) face (are facing). Therefore, the width H5 (see FIG. 2) where the members 2, 3 and the like forming the primary molded body 1 are joined can be reduced, and the manufactured resin molded body 15 can be downsized (compact). There are advantages that can be done.

  In addition, although the case where it heats with air was described in the said embodiment, it is not restricted to this, You may heat with gas other than air, Furthermore, instead of gas, the 1st, 2nd member You may use the liquid etc. which are hard to adhere to 2,3. That is, it is only necessary to heat the joint portions (joint portions 2b and 3b) of the primary molded body 1 with the heating fluid.

DESCRIPTION OF SYMBOLS 1 Resin molded object 2 1st member 2a, 3a Fitting part 2a, 3a Joint part junction part 4 Introduction flow path 5 Molten resin 6, 7 Mold 8 Gas introduction flow path 9 Gas discharge flow path 10 Electrical component 11 1st 1 Lifting piston (hot air / resin flow switching device)
12 Second lifting piston (hot air / resin flow switching device)
14 Hot air generator (heated gas generator)
15 resin moldings

Claims (8)

A method for producing a resin molded body in which a primary molded body is disposed in a mold, a molten resin is introduced into the mold and secondary processing is performed to manufacture a resin molded body,
Forming a flow passage for introduction surrounded by the primary molded body and the mold in a state where the primary molded body is disposed in the mold;
By heating a fluid to be introduced into the introduction flow path, the joined portion of the primary molded body is heated, and then a secondary process is performed by introducing molten resin into the introduction flow path and joining the primary molded body. The manufacturing method of the resin molding characterized by performing. The primary molded body is composed of a plurality of members, and the members are disposed in the mold so that the members face the introduction flow path.
By feeding a heating fluid into the introduction flow path, the joining portion between the members of the primary molded body is heated, and then, by introducing molten resin into the introduction flow path and joining the members to each other, The method for producing a resin molded body according to claim 1, wherein processing is performed.   The method for producing a resin molded body according to claim 1 or 2, wherein the joined portion of the primary molded body is heated by introducing the heated fluid into the introduction channel.   3. The resin molded body according to claim 1, wherein a gas is introduced into the introduction flow path while being compressed, and the joined portion of the primary molded body is heated by the compressed and heated gas. Production method.   The method for producing a resin molded body according to any one of claims 1 to 4, wherein the primary molded body is a hollow molded body including a plurality of members.   6. The method for producing a resin molded body according to claim 5, wherein an electrical component is enclosed in a primary molded body made of a hollow molded body. It manufactures with the manufacturing method of the resin molding of any one of Claims 1-6, The resin molding characterized by the above-mentioned. An electric apparatus comprising the resin molded body according to claim 7.

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