In-mold coat injection device, and method for injecting in-mold coat using the same

Abstract

To provide an in-mold coat injection device capable of reducing heat that a thermosetting liquid coating material before being injected from an injection machine into a mold receives from the mold, suppressing a curing reaction, thereby preventing occurrence of contamination and realizing a stable injection state.SOLUTION: An in-mold coat injection device 1 for injecting a thermosetting liquid coating material 4 into a coating gap 13 between an outer surface of a formed base material 3 held inside an upper mold 2b and a lower mold 2a which have been heated, and an inner surface of the upper mold 2b, comprises: an injection machine 8 having an injection port 6 and a tip valve portion 7d of an on-off valve 7 for opening / closing the injection port 6 at a tip portion 8a, to inject the thermosetting liquid coating material 4 jetted from the injection port 6 into the coating gap 13; and a heat insulation layer 9 provided between the tip portion 8a of the injection machine 8 and the upper mold 2b, and made of a material having a thermal conductivity lower than a thermal conductivity of a material of the tip portion 8a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an in-mold coat injection device for injecting a thermosetting liquid coating agent between a molding substrate held inside a heated mold and the inner surface of the mold, and an in-mold coat injection method using the same.

Background Art

[0002] In recent years, as interest in environmental issues has increased, an in-mold coating method (in-mold coating: IMC) has attracted attention as a coating alternative technology that does not use organic solvents and has a high CO2 emission reduction effect. In IMC, while a molding substrate is held, the other mold is pressed against the one mold covering the molding substrate, and a liquid coating agent is injected into the coating gap between the inner surface of the other mold and the outer surface of the molding substrate, and the liquid coating agent is solidified by heating to form a film on the outer surface of the molding substrate.

[0003] The characteristics of IMC include: (1) It is environmentally and user-friendly because it does not use organic solvents used in general spray coating; (2) Equipment for performing the coating process (spray spraying, oven heat treatment) is not required; (3) Since the paint is not diluted with an organic solvent, the ratio (coating efficiency) at which the material (paint) before application is formed as a coating film on the outer surface of the molding substrate is very high and waste is extremely small. IMC is used for the purpose of improving the quality of the surface of molded products and simplifying the coating process, and is widely used for exterior parts and the like, particularly in the automotive industry where the requirements for appearance and quality are high.

[0004] Incidentally, in the above-described liquid coating agent, a thermosetting resin in which non-resin substances having various functional characteristics (e.g., metals and inorganic substances with fine particle sizes) are blended and dispersed is often used in order to impart functional characteristics lacking in the material of the molding base material (e.g., thermoplastic resin) which is the material to be coated. Such a thermosetting liquid coating agent is cured by a chemical reaction due to the heat of the mold of the thermosetting resin serving as the main agent, and is coated on the outer surface of the molding base material. As an in-mold coat injection device for injecting such a thermosetting liquid coating agent into a mold in which a molding base material as the material to be coated is held inside, those shown in FIGS. 1(a), 1(b), 1(c), and 1(d) are known (see Patent Document 1).

[0005] As shown in FIG. 1(a), in this in-mold coat injection device a, with one mold b and the other mold c abutted to form a molding space f between the cavity d and the core e, as shown in FIG. 1(b), a molding material h (e.g., thermoplastic resin) is injected from the sprue g into the molding space f to mold the molding base material i. Immediately thereafter, as shown in FIG. 1(c), a thermosetting liquid coating agent j is injected as a coating agent onto the inner surface of the cavity d at a predetermined pressure. As shown in FIG. 1(d), the injected thermosetting liquid coating agent j penetrates between the inner surface of the cavity d and the outer surface of the molding base material i and cures, forming a coating on the outer surface of the molding base material i.

[0006] As shown in Fig. 1(a), this in-mold coat injection device a has a cylinder k provided on one mold b so as to connect to the inner surface of the cavity d, a rod-shaped piston l that freely moves up and down inside the cylinder k, and a hydraulic actuator m that moves the rod-shaped piston l up and down. Further, the in-mold coat injection device a includes a storage chamber n partitioned so as to connect to the upper part of the cylinder k, an introduction path o for introducing a thermosetting liquid coating agent j as a coat material into the storage chamber n, a discharge path p for discharging the thermosetting liquid coating agent j from the storage chamber n, and an external circulation line (not shown) that connects the discharge path o and the introduction path p. By returning the thermosetting liquid coating agent j in the discharge path p to the introduction path o via the circulation line and circulating the thermosetting liquid coating agent j in the storage chamber n, it is possible to suppress the thermosetting liquid coating agent j in the storage chamber n from being cured by the heat from the mold b.

[0007] The molding process and coating process of the molding base material i using this in-mold coat injection device a will be described. First, as shown in Fig. 1(a), the rod-shaped piston l is lowered until its lower end surface is flush with the cavity d, and a part of the molding space f is partitioned by the lower end surface of the rod-shaped piston l. In this state, as shown in Fig. 1(b), a molding material h (for example, a thermoplastic resin) is injected from the sprue g into the molding space f to mold the molding base material i. The molding base material i receives heat from the mold b in a heated and high-temperature state and retains its plasticity (soft state) for a certain period of time.

[0008] Immediately after molding the molding base material i, as shown in Fig. 1(c), the rod-shaped piston l is raised above the storage chamber n, guiding the thermosetting liquid coating agent j introduced into the storage chamber n from the introduction path o into the cylinder k. Then, as shown in Fig. 1(d), the rod-shaped piston l is lowered, and the thermosetting liquid coating agent j in the cylinder k is injected between the inner surface of the cavity d and the outer surface of the molding base material i at a predetermined pressure. The injected thermosetting liquid coating agent j penetrates between the inner surface of the cavity d and the outer surface of the molding base material i and is cured by a chemical reaction due to the heat of the mold b, forming a coating on the outer surface of the molding base material i.

Prior Art Documents

Patent Document

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] By the way, in the above-described conventional in-mold coating injection device a, as shown in FIGS. 1(a) to 1(d), since the rod-shaped piston l moves up and down inside the cylinder k to inject the thermosetting liquid coating agent j into the cavity d of the mold b, an extremely narrow clearance (gap) for allowing the sliding of both is required between the cylinder k and the rod-shaped piston l.

[0011] Therefore, as shown in FIGS. 1(a) and 1(b), in the state where the rod-shaped piston l is lowered and inserted into the cylinder k, the thermosetting liquid coating agent j in the storage chamber n infiltrates into the clearance between the cylinder k and the rod-shaped piston l in a very small amount, and is cured by the heat of the mold b that is heated to a high temperature. As a result, a cured layer of the cured thermosetting liquid coating agent j is formed in the clearance between the cylinder k and the rod-shaped piston l. This cured layer adheres to the inner surface of the cylinder k or the outer surface of the rod-shaped piston l.

[0012] When the cured layer of the thermosetting liquid coating agent j formed in the clearance between the cylinder k and the rod-shaped piston l adheres to the inner surface of the cylinder k, as shown in Fig. 1(c), this cured layer, as shown in Fig. 1(d), is scraped off by the edge of the lower end surface of the rod-shaped piston l when the rod-shaped piston l descends after the rod-shaped piston l is raised. The fragments of the scraped-off cured layer enter between the cavity d and the molding substrate i and become contaminants (impurities, foreign substances). When the fragments of the cured layer appear on the surface of the product, it results in a poor appearance. When the fragments of the cured layer exist at the interface between the molding substrate and the coating, it becomes the starting point of interface peeling and the adhesion is inhibited, resulting in defective products.

[0013] When the cured layer of the thermosetting liquid coating agent j formed in the clearance between the cylinder k and the rod-shaped piston l adheres to the outer surface of the rod-shaped piston l, as shown in Fig. 1(b), this cured layer, when the rod-shaped piston l in the descending state as shown in Fig. 1(c) is raised as shown in Fig. 1(c), is scraped off by the edge of the guide hole q formed on the ceiling surface of the storage chamber n to guide the rod-shaped piston l. The fragments of the scraped-off cured layer are mixed into the thermosetting liquid coating agent j in the storage chamber n. These scraped-off fragments of the cured layer are discharged from the storage chamber n through the discharge path p together with the thermosetting liquid coating agent j, mixed into the external circulation line (not shown), and return to the storage chamber n through the introduction path o. Therefore, hereafter, the thermosetting liquid coating agent j mixed with the scraped-off fragments of the cured layer will circulate. The scraped-off fragments of the cured layer in the storage chamber n are injected between the cavity d and the molding substrate i together with the thermosetting liquid coating agent j as the rod-shaped piston l descends as shown in Fig. 1(d), and the problems described in the previous paragraph occur.

[0014] An object of the present invention devised in consideration of the above circumstances is an in-mold coat injection device for injecting a thermosetting liquid coating agent between the outer surface of a molding base material held inside a heated mold and the inner surface of the mold, and an in-mold coat injection method using the same, which reduces the heat received by the thermosetting liquid coating agent from the mold before being injected from an injector into the mold, suppresses the curing reaction, prevents the occurrence of contamination, and provides an in-mold coat injection device and an in-mold coat injection method using the same that can achieve a stable injection state.

Means for Solving the Problems

[0015] According to the present invention devised to achieve the above object, there is provided an in-mold coat injection device for injecting a thermosetting liquid coating agent between the outer surface of a molding base material held inside a heated mold and the inner surface of the mold, comprising: an injector having an injection port and an on-off valve for opening and closing the injection port at its tip, and injecting the thermosetting liquid coating agent jetted from the injection port between the outer surface of the molding base material and the inner surface of the mold; and a heat insulation layer provided between the tip of the injector and the mold and made of a material having a lower thermal conductivity than the material of the tip, characterized by comprising the heat insulation layer.

[0016] In the in-mold coat injection device according to the present invention, a cooling mechanism may be provided in the injector to prevent the thermosetting liquid coating agent inside the injector from curing.

[0017] In the in-mold coat injection device according to the present invention, the tip of the injector may have an outer peripheral surface that is inserted into a mounting hole formed in the mold and a tip surface provided with the injection port, and the heat insulation layer may be provided on the outer peripheral surface of the tip so as to be in contact with the inner peripheral surface of the mounting hole.

[0018] In the in-mold coat injection device according to the present invention, the thermal conductivity of the heat insulation layer may be lower than the thermal conductivity of the mold.

[0019] In the in-mold coat injection device according to the present invention, the heat insulating layer may be a sprayed layer.

[0020] In the in-mold coat injection device according to the present invention, the sprayed layer may be a ceramic sprayed layer formed by spraying ceramic.

[0021] In the in-mold coat injection device according to the present invention, on the outer peripheral surface of the tip of the injector, a flange portion is provided on the tip surface side of the heat insulating layer provided on the outer peripheral surface, and the outer diameter of the edge of the flange portion is smaller than the outer diameter of the surface of the heat insulating layer, and a gap may be formed between the edge of the flange portion and the mounting hole of the mold.

[0022] In the in-mold coat injection device according to the present invention, the heat insulating layer may be a porous and porous material.

[0023] Further, according to the present invention, there is provided an in-mold coat injection method in which a thermosetting liquid coating agent is injected between the outer surface of a molding substrate and the inner surface of a mold using the above-described in-mold coat injection device, wherein the heat of the mold is transmitted to the tip of the injector through the heat insulating layer, thereby suppressing heat transfer from the mold to the tip of the injector, and suppressing the curing reaction of the thermosetting liquid coating agent in the vicinity of the injection port disposed at the tip of the injector and the on-off valve for opening and closing the injection port.

[0024] Further, according to the present invention, there is provided an in-mold coat injection method in which a thermosetting liquid coating agent is injected between the outer surface of a molding substrate and the inner surface of a mold using the above-described in-mold coat injection device, wherein a part of the thermosetting liquid coating agent ejected from the injection port of the injector enters the gap between the mounting hole of the mold and the edge of the flange portion of the injector, and the thermosetting liquid coating agent that has entered the gap is cured by the heat from the mold, thereby preventing the thermosetting liquid coating agent ejected from the injection port from entering the heat insulating layer through the gap.

Effects of the Invention

[0025] According to the in-mold coat injection device and the in-mold coat injection method using the same according to the present invention, the following effects can be achieved. (1) In an in-mold coat injection device that injects a thermosetting liquid coating agent between the outer surface of a molding substrate held inside a heated mold and the inner surface of the mold, an injection machine having an injection port and an on-off valve for opening and closing the injection port at its tip, and injecting the thermosetting liquid coating agent ejected from the injection port between the outer surface of the molding substrate and the inner surface of the mold, and a heat insulating layer made of a material having a lower thermal conductivity than the material of the tip is provided between the tip of the injection machine and the mold. Therefore, the heat of the mold is transmitted to the tip of the injection machine through the heat insulating layer, and heat transfer from the mold to the tip of the injection machine is suppressed, and the heat received by the thermosetting liquid coating agent in the vicinity of the injection port disposed at the tip and the on-off valve for opening and closing the injection port from the mold can be reduced. (2) As a result, the curing reaction of the thermosetting liquid coating agent in the vicinity of the injection port of the injection machine and the on-off valve for opening and closing the injection port, that is, the curing reaction of the thermosetting liquid coating agent before injection is suppressed, generation of contamination can be prevented, and a stable injection state can be realized.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are not shown.

[0028] (Overview of the In-Mold Coat Injection Device 1) As shown in FIG. 2, an in-mold coat injection device 1 according to an embodiment of the present invention injects a thermosetting liquid coating agent 4 between the outer surface of a molding base material 3 held inside a heated mold 2 and the inner surface of the mold 2. This in-mold coat injection device 1 has an injection port 6 and an on-off valve 7 (tip valve portion 7d) for opening and closing the injection port 6 at its tip portion 8a, and injects the thermosetting liquid coating agent 4 jetted from the injection port 6 between the outer surface of the molding base material 3 and the inner surface of the mold 2. The injection device 8 is provided, and a heat insulating layer 9 made of a material having a lower thermal conductivity than the material of the tip portion 8a is provided between the tip portion 8a of the injection device 8 and the mold 2.

[0029] As shown in FIGS. 3 and 4, the injection device 8 is provided with a cooling mechanism 10 to prevent the thermosetting liquid coating agent 4 inside the injection device 8 from curing. The tip portion 8a of the injection device 8 has an outer peripheral surface 8x that is inserted into the tip hole portion 11a of a mounting hole 11 formed in the mold 2 and a tip surface 8y provided with the injection port 6. The heat insulating layer 9 is provided on the outer peripheral surface 8x of the tip portion 8a so as to be in contact with the inner peripheral surface of the mounting hole 11. The thermal conductivity of the heat insulating layer 9 is lower than the thermal conductivity of the material of the mold 2, and the heat insulating layer 9 is formed of a sprayed layer. As the heat insulating layer 9, a ceramic sprayed layer formed by spraying ceramic is used. Hereinafter, each component will be described.

[0030] (Mold 2) As shown in FIG. 2, the mold 2 includes one mold 2a (hereinafter also referred to as the lower mold 2a) provided with a convex core 12 to which a separately molded molding base material 3 is attached, and is disposed opposite thereto. A cavity 14 is recessed so that a predetermined coating gap 13 (for example, 50 μm to 100 μm) is formed between the outer surface of the molding base material 3 attached to the core 12 of the lower mold 2a and the other mold 2b (hereinafter also referred to as the upper mold 2b). The upper mold 2b is attached to the lower surface of the upper platen 15 with bolts (not shown) via a heat insulating plate 16, and the lower mold 2a is attached to the upper surface of the lower platen 17 with bolts (not shown). By moving the lower platen 17 in the vertical direction with respect to the upper platen 15, the lower mold 2a approaches and separates from the upper mold 2b to perform mold clamping and mold opening.

[0031] As shown in FIGS. 2 and 5, on the mating surface (parting surface) between the lower mold 2a and the upper mold 2b, a runner groove 18 is formed to supply a thermosetting liquid coating agent 4 (for example, a one-component curable thermosetting paint, hereinafter simply referred to as paint) to the coating gap 13 between the outer surface of the molding substrate 3 and the inner surface of the cavity 14 of the upper mold 2b during mold clamping. The runner groove 18 accommodates a runner 3a generated when the molding substrate 3 is molded by another molding die (not shown) instead of the upper mold 2b. As shown in FIGS. 7 and 8, the paint 4 is injected from the injection port 6 of the injector 8, passes through the runner groove 18, and is injected into the coating gap 13 along the runner 3a.

[0032] As shown in FIGS. 2 and 5, the upper mold 2b is provided with a heating mechanism 19 for heating and curing the paint 4 injected into the coating gap 13 through the runner groove 18. For the heating mechanism 19, for example, a heating wire (electric resistance wire) that generates heat by energization is used. The heating mechanism 19 (heating wire) is disposed near the ceiling surface of the cavity 14 that partitions the coating gap 13. The heating mechanism 19 is also provided on the lower mold 2a. The heating mechanism 19 of the lower mold 2a prevents the upper mold 2b from being cooled by the lower mold 2a during mold clamping when the lower mold 2a abuts against the upper mold 2b, and suppresses a temperature drop in the coating gap 13. Further, the heat insulating plate 16 interposed between the upper mold 2b and the upper platen 15 exhibits a function of suppressing the heat of the upper mold 2b from being transmitted to the upper platen 15. Thereby, the heat input from the upper platen 15 to the injector 8 is reduced, and the progress of the curing reaction of the paint 4 introduced into the injector 8 is suppressed.

[0033] (Injector 8) As shown in FIGS. 2 and 5, when the lower mold 2a holding the molding base material 3 is pressed against the upper mold 2b, a coating gap 13 of a predetermined size (for example, 50 μm to 100 μm) is formed between the inner surface of the cavity 14 of the upper mold 2b and the outer surface of the molding base material 3. An injector 8 is attached to the upper mold 2b for injecting a predetermined amount of paint 4 into the coating gap 13 corresponding to the volume of the space. At the tip 8a of the injector 8, an injection port 6 for injecting the paint 4 into the coating gap 13 and an on-off valve 7 (tip valve portion 7d) for opening and closing the injection port 6 are provided. The tip 8a of the injector 8 has an outer peripheral surface 8x that is inserted into the tip hole portion 11a of the mounting hole 11 formed in the upper mold 2b and a tip surface 8y provided with the injection port 6. A heat insulating layer 9 is provided on the outer peripheral surface 8x of the tip 8a so as to contact the inner peripheral surface of the tip hole portion 11a of the mounting hole 11.

[0034] As shown in FIG. 2, the injector 8 has a three-stage cylindrical body in which a small-diameter tip portion 8a, a medium-diameter portion 8b having a larger diameter than that, and a large-diameter portion 8c having a larger diameter than that are connected in series from below to above. A mounting flange 20 is provided on the outer peripheral surface of the large-diameter portion 8c. The mounting flange 20 is attached to the upper platen 15 by bolts 21. As shown in FIG. 5, a mounting hole 11 for accommodating the injector 8 is formed in the upper mold 2b so as to penetrate the upper and lower surfaces. The mounting hole 11 includes a tip hole portion 11a having a hole diameter corresponding to the tip portion 8a of the injector 8 and a medium-diameter hole portion 11b having a hole diameter larger than that of the medium-diameter portion 8b of the injector 8. The tip hole portion 11a is connected to the runner groove 18 via a coating agent reservoir portion 26, and a predetermined gap 22 is formed between the medium-diameter hole portion 11b and the medium-diameter portion 8b. The gap 22 functions as an air heat insulating layer that suppresses the heat of the upper mold 2b from being transmitted to the injector 8.

[0035] As shown in FIG. 5, a through hole 23 having a hole diameter larger than that of the large-diameter portion 8c of the injector 8 is formed in the upper platen 15 for accommodating the large-diameter portion 8c of the injector 8. A gap 24 is formed between the through hole 23 and the large-diameter portion 8c of the injector 8, and the gap 24 functions as an air heat insulating layer that suppresses the heat that has been transmitted to the upper platen 15 in a small amount from the upper mold 2b via the heat insulating plate 16 from being transmitted to the injector 8.

[0036] As shown in FIG. 5, a heat insulating ring 25 is provided between the step from the large-diameter portion 8c to the medium-diameter portion 8b of the injector 8 and the upper surface of the upper mold 2b to suppress the heat of the upper mold 2b from being transmitted to the injector 8. The heat insulating ring 25 functions to suppress the heat of the upper mold 2b from being transmitted to the injector 8 and to suppress the paint 4 introduced into the injector 8 from undergoing a curing reaction due to the heat from the upper mold 2b. Further, when the bolt 21 is screwed in, the heat insulating ring 25 is sandwiched between the lower surface of the large-diameter portion 8c and the upper surface of the upper mold 2b and is slightly crushed, and by the restoring force thereof, the male screw portion of the bolt 21 and the female screw portion of the screw hole for the bolt 21 formed in the upper platen 15 are pressed against each other in the axial direction, so that the heat insulating ring 25 also functions as a locking member for the bolt 21.

[0037] (Heat insulating layer 9) As shown in FIGS. 3 and 5, an injection port 6 for injecting the paint 4 and a tip valve portion 7d of an on-off valve 7 for opening and closing the injection port 6 are provided at the tip end portion 8a of the injector 8. The tip end portion 8a of the injector 8 has an outer peripheral surface 8x that is inserted into the tip hole portion 11a of the mounting hole 11 formed in the upper mold 2b and a tip end surface 8y provided with the injection port 6. A step surface 8z having a diameter slightly smaller than that of the outer peripheral surface 8x is formed on the outer peripheral surface 8x, and a heat insulating layer 9 is provided on the step surface 8z so as to be in contact with the tip hole portion 11a of the mounting hole 11. The heat insulating layer 9 is made of a material having a lower thermal conductivity than that of the material of the tip end portion 8a of the injector 8, suppresses the heat of the upper mold 2b from being transmitted to the tip end portion 8a of the injector 8, and reduces the heat received by the paint 4 (thermosetting liquid coating agent) in the vicinity of the injection port 6 and the tip valve portion 7d of the on-off valve 7 provided at the tip end portion 8a of the injector 8 from the upper mold 2b. Thereby, the curing reaction of the paint 4 in the vicinity of the injection port 6 of the injector 8 and the tip valve portion 7d of the on-off valve 7 thereof, that is, the curing reaction of the paint 4 before injection (immediately before injection) is suppressed, and the situation where the cured paint 4 becomes contamination (impurities, foreign matters) and is injected into the coating gap 13 can be prevented, and a stable injection state can be realized.

[0038] (Ceramic as the material of the heat insulating layer 9) The thermal conductivity of the heat insulation layer 9 shown in FIGS. 3 and 5 is lower than that of the material of the tip 8a of the injector 8 and lower than that of the material of the mold 2 (upper mold 2b, lower mold 2a). For example, when the material of the injector 8 including the tip 8a, the material of the upper mold 2b, and the material of the lower mold 2a are iron-based metals (such as steel, cast iron, etc.), the material of the heat insulation layer 9 is a ceramic with a lower thermal conductivity than the iron-based metal. Examples of the ceramic include zirconia, steatite, cordierite, forsterite, yttria, cermet, silicon nitride, alumina, etc. For example, the thermal conductivity of single zirconia is 3 W / m·K, which is about 1 / 10 of the thermal conductivity (25 - 30 W / m·K) of iron-based metals (such as steel, cast iron, etc.). Therefore, when zirconia is used as the material of the heat insulation layer 9, compared with the case where the heat insulation layer 9 does not exist (when the tip hole 11a of the mounting hole 11 formed in the upper mold 2b is in direct contact with the tip 8a of the injector 8), the heat input from the upper mold 2b to the tip 8a of the injector 8 can be reduced to about 1 / 10.

[0039] By the way, it is also conceivable to use GFRP in which epoxy resin, phenolic resin, etc. are added to glass fiber instead of ceramic as the material of the heat insulation layer 9 shown in FIGS. 3 and 5. The thermal conductivity of GFRP is 0.5 - 1.0 W / m·K, which is extremely low compared with the thermal conductivity of iron-based metals (25 - 30 W / m·K), and it is more advantageous than ceramic in terms of heat insulation. However, when GFRP is used for the heat insulation layer 9, considering the adhesion to the paint 4 sprayed from the injection port 6 to the lower coating agent reservoir portion 26, since GFRP has minute irregularities on the surface due to glass fiber and the contact area with the paint is large, resulting in a wedge effect, the paint 4 sprayed from the injection port 6 to the coating agent reservoir portion 26 easily adheres to the end face of the heat insulation layer 9 made of GFRP. Therefore, as shown in FIG. 8, after the injection of the paint 4 into the coating gap 13 is completed, when the lower mold ½ is separated from the upper mold 2b and the molded base material 3 (product) coated with the paint 4 is taken out, the paint 4 in the coating agent reservoir portion 26 may adhere to the end face of the heat insulation layer 9 made of GFRP, making it difficult to demold the product. Therefore, it cannot be said that it is appropriate to use GFRP as the material of the heat insulation layer 9.

[0040] In addition, it is also conceivable to use an olefin-based resin such as polypropylene / polyethylene or a fluororesin (such as Teflon (registered trademark)) that is difficult to chemically adhere to the material of the heat insulation layer 9 shown in FIG. 8 with the paint 4 injected from the injection port 6 to the coating agent reservoir 26 below. However, since olefin-based resins have low heat resistance, they cannot be used for the heat insulation layer 9. That is, the paint 4 (thermosetting liquid coating agent) injected from the injection port 6 to the coating agent reservoir 26 has a temperature (for example, about 100°C) at which the thermosetting coating agent is appropriately cured. Considering this temperature, it cannot be said that it is a good idea to use an olefin-based resin with low heat resistance for the heat insulation layer 9. Also, Teflon (registered trademark) has insufficient rigidity, making it difficult to obtain a processing accuracy of several microns, and when used for the heat insulation layer 9, it cannot prevent the leakage of the paint. That is, the heat insulation layer 9 also functions as a packing to prevent the paint 4 injected from the injection port 6 of the tip 8a of the injector 8 to the coating agent reservoir 26 from leaking upward between the tip 8a and the tip hole 11a. However, Teflon (registered trademark) has insufficient rigidity, making it difficult to obtain the necessary processing accuracy, and there is a possibility that it may not function properly as a packing, so it cannot be said that it is a good idea to use it for the heat insulation layer 9. Based on the above considerations, in this embodiment, ceramic is used as the material of the heat insulation layer 9.

[0041] (Ceramic spraying layer as the heat insulation material 9) As described above, the heat insulation layer 9 shown in FIGS. 3 and 5 is composed of a ceramic spraying layer formed by spraying a ceramic such as zirconia. The ceramic spraying layer 9 is formed by spraying a ceramic such as zirconia on the stepped surface 8z of the outer peripheral surface 8x of the tip 8a of the injector 8 slightly thicker than the specified dimension (the hole diameter of the tip hole 11a of the mounting hole 11), and then polishing (cutting) it to the specified dimension. Thereby, the thickness of the heat insulation layer 9 (ceramic spraying layer) can be made as thin as possible. In this embodiment, the thickness of the ceramic spraying layer 9 is about 0.3 mm.

[0042] On the other hand, it is also conceivable to form a sleeve from ceramic and attach it to the tip 8a of the injector 8 to serve as the heat insulation layer 9. However, due to problems with strength and rigidity, it is necessary to make the thickness of the ceramic sleeve somewhat thick. As a result, the thickness of the ceramic sleeve as the heat insulation layer 9 becomes much thicker compared to the ceramic sprayed layer. As a result, when inserting the tip 8a of the injector 8 with the ceramic sleeve attached into the tip hole 11a of the mounting hole 11 formed in the upper mold 2b, the hole diameter of the tip hole 11a becomes larger, increasing the volume of the coating agent reservoir 26. The paint 4 cured in the coating agent reservoir 26 becomes a lump and is discarded, deteriorating the material yield.

[0043] In the present embodiment, by using a ceramic sprayed layer as the heat insulation layer 9, the inner diameter of the tip hole 11a of the mounting hole 11 formed for inserting the tip 8a of the injector 8 into the upper mold 2b can be made as small as possible compared to the case of using a ceramic sleeve. Therefore, the volume of the coating agent reservoir 26 partitioned by the tip surface 8y (lower surface) of the tip 8a of the injector 8, the inner peripheral surface of the tip hole 11a of the mounting hole 11, and the lower mold 2a can be reduced. The coating agent reservoir 26 is connected to the runner groove 18. The paint 4 cured in the coating agent reservoir 26 is removed (cut off) from the molded base material 3 (product) coated with the paint 4 together with the runner cured in the runner groove 18 in a subsequent process. Therefore, by reducing the volume of the coating agent reservoir 26, the amount of paint 4 discarded according to the volume of the coating agent reservoir 26 is reduced, improving the material yield of the paint 4.

[0044] Also, as shown in FIGS. 3 and 5, in this embodiment, since the heat insulation layer 9 (ceramic sprayed layer) is formed on the stepped surface 8z that is slightly smaller than the outer peripheral surface 8x on the outer peripheral surface 8x of the tip portion 8a of the injector 8, compared with the case where the ceramic sprayed layer 9 is directly formed on the outer peripheral surface 8x of the tip portion 8a of the injector 8 (when the stepped surface 8z does not exist), the inner diameter of the tip hole portion 11a of the mounting hole 11 can be reduced by the dimension of the step between the stepped surface 8z and the outer peripheral surface 8x. As a result, the volume of the coating agent reservoir portion 26 is reduced, the amount of the paint 4 discarded according to the volume of the coating agent reservoir portion 26 is reduced, and the material yield of the paint 4 is improved.

[0045] (Measuring cylinder 27, piston 28) As shown in FIG. 5, inside the injector 8, a measuring cylinder 27 for accommodating a predetermined amount of the paint 4 is formed. The measuring cylinder 27 is formed inside the large-diameter portion 8c of the injector 8 and is arranged at a position in the injector 8 that is least affected by the heat of the upper mold 2b by the above-described heat insulation layer 9, heat insulation ring 25, gap 22 (air heat insulation layer), and gap 24 (air heat insulation layer). In this embodiment, the measuring cylinder 27 is arranged above the upper surface of the upper mold 2b and above the heat insulation ring 25. Inside the measuring cylinder 27, a piston 28 is provided so as to be movable in the axial direction (vertical direction). The piston 28 includes a piston main body portion 28a having a diameter that slides in the measuring cylinder 27 and a piston protruding portion 28b provided at a portion protruding from the measuring cylinder 27 above the piston main body portion 28a.

[0046] (Inlet port 6) As shown in FIG. 5 and FIG. 9, inside the middle diameter portion 8b and the tip portion 8a of the injector 8 shown in FIG. 2, a passage hole 29 having a smaller diameter than the metering cylinder 27 is formed so as to be connected to the metering cylinder 27 and directed downward. A conical valve seat 30 is formed at the lower end of the passage hole 29, and an injection port 6 is formed at the lower end of the valve seat 30 so as to communicate with the coating agent reservoir portion 26. The injection port 6 is closed when the tip valve portion 7d at the lower end of the on-off valve 7 seats on the valve seat 30, and is opened when the tip valve portion 7d at the lower end of the on-off valve 7 is separated from the valve seat 30. When the valve is opened, the paint 4 in the metering cylinder 27 is injected from the injection port 6 through the passage hole 29 into the coating agent reservoir portion 26, and is injected from the coating agent reservoir portion 26 through the runner groove 18 into the coating gap 13.

[0047] (Supply passage 32) As shown in FIG. 5, a supply port 31 for supplying the paint 4 to the metering cylinder 27 is provided on the side portion of the large diameter portion 8c of the injector 8 so as to be connected to the metering cylinder 27. A supply passage 32 for supplying the paint 4 to the metering cylinder 27 is connected to the supply port 31. The supply passage 32 is inserted into a hole formed in the upper platen 15 with a diameter larger than the outer diameter of the supply passage 32. A gap 33 is formed between the hole and the supply passage 32. The gap 33 serves as an air heat insulation layer for suppressing the heat of the upper platen 15 from being transmitted to the paint 4 flowing in the supply passage 32.

[0048] (Supply valve 34) As shown in Fig. 2, in the supply passage 32 shown in Figs. 5 to 6, when the piston 28 moves in the suction direction (upward) to expand the volume of the metering cylinder 27, the supply passage 32 is opened (note that Fig. 6 shows a state where the filling of the paint 4 into the metering cylinder 27 is completed and the supply valve 34 is closed). As shown in Figs. 7 to 8, a supply valve 34 is provided to close the supply passage 32 when the piston 28 moves in the discharge direction (downward) to reduce the volume of the metering cylinder 27. In this embodiment, the supply valve 34 is a check valve that allows the paint 4 to flow from the supply passage 32 into the metering cylinder 27 and prevents it from flowing from the metering cylinder 27 into the supply passage 32. However, the supply valve 34 may be a control valve that opens and closes the supply passage 32 as described above. As shown in Fig. 2, a paint tank 35 containing the paint 4 is connected to the upstream side of the supply valve 34 via a pipe 36.

[0049] (On-off valve 7) As shown in Fig. 5, a hole 37 is formed through the piston 28 in the axial direction (vertical direction), and a long and narrow on-off valve 7 is slidably mounted in the axial direction in the hole 37. The on-off valve 7 includes a middle diameter portion 7a having a diameter that slides in the hole 37, a tip portion 7b integrally provided below the middle diameter portion 7a, and a large diameter portion 7c integrally provided above the middle diameter portion 7a. The tip portion 7b is accommodated in the passage hole 29 with a predetermined gap in the diameter direction, and a tip valve portion 7d formed in a conical shape is provided at its lower end so as to seat on the valve seat 30. The large diameter portion 7c has a diameter that slides in a hole 38 formed in the axial direction inside the piston projection 28b, and its upper part projects upward from the piston projection 28b. Such an on-off valve 7 is in an open valve position where the tip valve portion 7d separates from the valve seat 30 to open the injection port 6 when rising, and in a closed valve position where the tip valve portion 7d seats on the valve seat 30 to close the injection port 6 when descending.

[0050] (Actuator 39) The piston 28 and the on-off valve 7 shown in Fig. 5 are respectively lifted or lowered as appropriate by the actuator 39. As shown from Fig. 5 to Fig. 6, the actuator 39 moves in the suction direction to lower the on-off valve 7 to the closed valve position and lift the piston 28, guiding the paint 4 in the paint tank 35 shown in Fig. 2 from the supply port 31 into the metering cylinder 27 through the pipe 36 to fill the metering cylinder 27 with a predetermined amount of paint 4. Then, as shown from Fig. 7 to Fig. 8, the actuator 39 moves in the discharge direction to lift the on-off valve 7 to the open valve position and lower the piston 28, injecting the predetermined amount of paint 4 in the metering cylinder 27 from the injection port 6 into the coating agent reservoir 26.

[0051] As shown in Fig. 5, the actuator 39 includes a piston actuating flange 40 formed on a portion (piston protruding portion 28b) of the piston 28 protruding from the metering cylinder 27 to move the piston 28 in the axial direction of the metering cylinder 27, a piston actuating cylinder 41 formed to movably accommodate the piston actuating flange 40 along the axial direction of the metering cylinder 27, a on-off valve actuating flange 42 formed on a portion (on-off valve protruding portion 7e) of the large-diameter portion 7c of the on-off valve 7 protruding from the piston 28 to move the on-off valve 7 in the axial direction of the piston 28, and an on-off valve actuating cylinder 43 formed by connecting the on-off valve actuating flange 42 to the piston actuating cylinder 41 to movably accommodate it along the axial direction of the piston 28.

[0052] As shown in FIG. 5, the piston-actuating cylinder 41 and the on-off valve-actuating cylinder 43 are respectively formed inside a cylinder block 45 attached to the upper platen 15 via a support column 44. In the cylinder block 45, a first passage 46 for applying fluid pressure to the upper surface of the on-off valve-actuating flange 42 and the lower surface of the piston-actuating flange 40, and a second passage 47 for applying fluid pressure to the lower surface of the on-off valve-actuating flange 42 and the upper surface of the piston-actuating flange 40 are formed. The first passage 46 includes a passage 46a connecting a hole formed in one side surface of the cylinder block 45 and a portion above the on-off valve-actuating flange 42 of the on-off valve-actuating cylinder 43, and a passage 46b connecting a middle portion of the passage 46a and a portion below the piston-actuating flange 40 of the piston-actuating cylinder 41. The second passage 47 connects a hole formed in the other side surface of the cylinder block 45 and a portion above the piston-actuating flange 40 of the piston-actuating cylinder 41.

[0053] Also, as shown from FIG. 5 to FIG. 6, the actuator 39 supplies fluid (such as air, water, oil, etc.) to the first passage 46 to apply fluid pressure to the upper surface of the on-off valve-actuating flange 42 and the lower surface of the piston-actuating flange 40, so that the on-off valve 7 closes the injection port 6 and the piston 28 moves in the suction direction in the metering mode, and as shown from FIG. 7 to FIG. 8, supplies fluid to the second passage 47 to apply fluid pressure to the lower surface of the on-off valve-actuating flange 42 and the upper surface of the piston-actuating flange 40, so that the on-off valve 7 opens the injection port 6 and the piston 28 moves in the discharge direction in the injection mode. To switch between the two modes, the actuator 39 is provided with fluid pressure switching means 48 (see FIG. 2).

[0054] (Fluid pressure switching means 48) As shown in FIG. 2, the fluid pressure switching means 48 includes a switching valve 49 connected to the first passage 46 and the second passage 47, a tank T (such as an air tank, a water tank, an oil tank, etc.) in which a fluid (such as air, water, oil, etc.) is stored at a predetermined pressure to supply fluid pressure (such as air pressure, water pressure, oil pressure, etc.), a pump P for pressurizing and supplying the fluid to the tank T, and a control unit C for appropriately switching the switching valve 49. In this embodiment, an example is shown in which air (air) is used as the fluid and an electromagnetic solenoid valve is used as the switching valve 49.

[0055] When electricity is not supplied from the control unit C to the solenoid 49a of the electromagnetic solenoid valve (switching valve 49) shown in FIG. 2, the box is pushed to the right by the spring 49b and the parallel circuit functions. As a result, the air in the tank T is supplied to the first passage 46, and the air in the second passage 47 is exhausted from the exhaust silencer 50. Thereby, as shown from FIG. 5 to FIG. 6, the on-off valve 7 descends to the closed valve position, the piston 28 moves upward (suction direction), and the metering mode is entered.

[0056] On the other hand, when electricity is supplied from the control unit C shown in FIG. 2 to the solenoid 49a, the solenoid 49a is excited and the box is moved to the left, and the cross circuit functions. As a result, the air in the tank T is supplied to the second passage 47, and the air in the first passage 46 is exhausted from the exhaust silencer 50. Thereby, as shown from FIG. 7 to FIG. 8, the on-off valve 7 rises to the open valve position, the piston 28 moves downward (discharge direction), and the injection mode is entered.

[0057] (Cooling mechanism 10) As shown in FIGS. 4(a) and 4(b), a cooling mechanism 10 is provided inside the injector 8 to prevent the paint 4 (thermosetting liquid coating agent) inside the injector 8 from curing. As shown in FIGS. 4(b) and 5, the cooling mechanism 10 includes a cooling water passage 10a formed so as to surround the metering cylinder 27 and the passage hole 29. The cooling water passage 10a is formed in a double spiral shape so as to surround the metering cylinder 27 and the passage hole 29, and the cooling water introduced from the inlet 10b formed on the left side of the upper part of the injector 8 descends counterclockwise as viewed from above, turns back at the lower part of the injector 8, rises clockwise, and is discharged from the outlet 10c formed on the right side of the upper part of the injector 8. The injector 8 in which the cooling water passage 10a having such a complex shape is formed is manufactured by a metal 3D printer, lost wax casting, or the like. The cooling water flowing through the cooling water passage 10a can suppress the paint 4 accommodated in the metering cylinder 27 and the passage hole 29 from being excessively heated by the heat from the upper mold 2b and the curing reaction from proceeding.

[0058] (Measurement start) When guiding a predetermined amount of paint 4 to the injector 8 of the in-mold coat injection device 1 shown in FIG. 2, first, the fluid (air) in the tank (air tank) T is supplied to the first passage 46 as shown in FIG. 5. Then, the on-off valve 7 descends to the closed valve position, and the piston 28 rises. As a result, the inside of the metering cylinder 27 becomes negative pressure, and the paint 4 in the paint tank 35 shown in FIG. 2 is guided to the metering cylinder 27 through the supply valve 34 (check valve). Here, in case the tip valve portion 7d of the on-off valve 7 separates from the valve seat 30, the paint 4 will leak from the injection port 6. Therefore, a leak prevention spring 48a for pressing the tip valve portion 7d against the valve seat 30 by biasing the on-off valve 7 downward is provided on the ceiling surface of the cylinder block 45 above the flange 42 for on-off valve operation. Therefore, even if the actuator 39 malfunctions or an emergency stop occurs and control becomes impossible, the paint 4 inside the injector 8 will not leak into the mold 2. The fluid (air) above the piston operating flange 40 in the piston operating cylinder 41 is discharged from the second passage 47 as the piston operating flange 40 rises, and is exhausted from the exhaust silencer 50.

[0059] (Measurement completed) As shown in Fig. 6, when the piston operating flange 40 of the piston 28 abuts against the ceiling surface of the piston operating cylinder 41, the piston 28 reaches the top dead center, a predetermined amount of paint 4 is stored in the metering cylinder 27, and the metering is completed.

[0060] (Injection start) Next, in order to inject a predetermined amount of paint 4 from the injection port 6 into the coating agent reservoir 26, the fluid (air) in the air tank T shown in Fig. 2 is supplied to the second passage 47 as shown in Fig. 7. Then, the on-off valve 7 rises and the injection port 6 is opened, and the piston 28 descends to reduce the volume of the metering cylinder 27. As a result, the paint 4 in the metering cylinder 27 is injected from the injection port 6 into the coating agent reservoir 26. At this time, the supply valve 34 (check valve) prevents the paint 4 in the metering cylinder 27 from flowing back to the paint tank 35 side shown in Fig. 2. Note that the fluid below the piston operating flange 40 in the piston operating cylinder 41 is discharged from the first passage 46 as the piston operating flange 40 descends, and the fluid above the on-off valve operating flange 42 in the on-off valve operating cylinder 43 is discharged from the first passage 46 as the on-off valve operating flange 42 rises.

[0061] (Injection completed) As shown in Fig. 8, when the lower surface of the stroke adjustment ring 51 provided on the piston 28 abuts against the upper surface of the injector 8, the piston 28 reaches the bottom dead center, and the injection of a predetermined amount of paint 4 is completed. By appropriately changing the thickness t of the stroke adjustment ring 51, the stroke S (see Fig. 6) from the top dead center to the bottom dead center can be adjusted, and the injection amount of the paint 4 can be adjusted. Also, by pressing the tip valve portion 7d of the on-off valve 7 against the valve seat 30 with the leak prevention spring 48a, it is possible to prevent the paint 4 in the injector 8 from leaking into the coating agent reservoir 26 in the mold 2.

[0062] (Function and effect) According to the in-mold coat injection device 1 according to the present embodiment and the in-mold coat injection method using the same, the following effects can be exhibited.

[0063] As shown in FIG. 2, in the in-mold coat injection device 1 according to the present embodiment, a coating agent, paint 4 (thermosetting liquid coating agent), is injected into a coating gap 13 between the outer surface of a molding substrate 3 held inside a mold 2 (upper mold 2b, lower mold 2a) heated by a heating mechanism 19 and the inner surface of a cavity 14 of the upper mold 2b in a predetermined amount corresponding to the volume of the space formed by the coating gap 13.

[0064] As shown in FIG. 5, this in-mold coat injection device 1 has an injection port 6 at its tip 8a and a tip valve portion 7d of an on-off valve 7 that opens and closes the injection port 6, and an injection machine 8 for injecting the paint 4 injected from the injection port 6 into the coating gap 13 between the outer surface of the molding substrate 3 and the inner surface of the cavity 14 of the upper mold 2b. The injection machine 8 is provided with a heat insulating layer 9 made of a material (ceramic) having a lower thermal conductivity than the material (steel, cast iron, etc.) of the tip 8a, between the tip 8a of the injection machine 8 and the tip hole portion 11a of the mounting hole 11 of the upper mold 2b.

[0065] Therefore, as shown in FIG. 2, the heat of the heating mechanism 19 provided for curing the paint 4 (thermosetting liquid coating agent) injected into the coating gap 13 in the upper mold 2b is transmitted to the tip 8a of the injection machine 8 through the heat insulating layer 9, and heat transfer from the upper mold 2b to the tip 8a of the injection machine 8 is suppressed. As shown in FIGS. 7 and 8, the heat received by the paint 4 (thermosetting liquid coating agent) in the vicinity of the injection port 6 provided at the tip 8a and the tip valve portion 7d of the on-off valve 7 that opens and closes the injection port 6 can be reduced.

[0066] As a result, in FIGS. 7 and 8, the curing reaction of the paint 4 in the vicinity of the injection port 6 of the injection machine 8 and the tip valve portion 7d of the on-off valve 7 that opens and closes the injection port 6, that is, the curing reaction of the paint 4 immediately before injection into the coating gap 13, is suppressed, and the generation of contaminants (impurities, foreign substances), blockage of the injection port 6, adhesion of the tip valve portion 7d of the on-off valve 7 to the valve seat 30, adhesion of the tip portion 7b of the on-off valve 7 to the passage hole 29, etc., caused by the curing of the paint 4 can be prevented, and a stable injection state can be realized.

[0067] Further, as shown in FIGS. 3 and 4, in order to prevent the paint 4 (thermosetting liquid coating agent) inside the injector 8 from curing, a cooling mechanism 10 for cooling the paint 4 inside the injector 8 is provided in the injector 8. Therefore, as shown in FIG. 2, even if a part of the heat of the upper mold 2b heated by the heating mechanism 19 provided to cure the paint 4 injected into the coating gap 13 in the upper mold 2b passes through the heat insulating layer 9 and is transmitted to the tip portion 8a of the injector 8, the paint 4 (thermosetting liquid coating agent) in the vicinity of the injection port 6 at the tip portion 8a of the injector 8 and the tip valve portion 7d of the on-off valve 7 for opening and closing the injection port 6 can be maintained at a temperature at which an appropriate curing reaction can be exhibited.

[0068] (Modification example) By the way, in order to enhance the heat insulation property of the heat insulating layer 9 (ceramic sprayed layer) provided on the stepped surface 8z of the outer peripheral surface 8x of the tip portion 8a of the injector 8 shown in FIG. 8, it is conceivable to spray ceramic on the stepped surface 8z of the outer peripheral surface 8x of the tip portion 8a so that the ceramic sprayed layer 9 becomes a porous porous body. Thereby, the thermal conductivity of the heat insulating layer 9 (ceramic sprayed layer) can also be lowered to 1 W / m·K or less, and the heat input from the upper mold 2b to the tip portion 8a of the injector 8 can be significantly reduced. However, if the heat insulating layer 9 (ceramic sprayed layer) is made into a porous porous body, a part of the paint 4 (thermosetting liquid coating agent) sprayed from the injection port 6 of the injector 8 to the coating agent reservoir portion 26 may come into contact with the end surface of the heat insulating layer 9 (ceramic sprayed layer) and bite, making demolding difficult. A modification example for solving this will be described with reference to FIGS. 9 and 10.

[0069] FIG. 9(a) shows a cross-sectional view of the tip portion 8a of the injector 8 of the in-mold coat injection device 1 according to a modification example of the present invention. Since the in-mold coat injection device 1 according to the modification example has the same basic configuration as the in-mold coat injection device 1 according to the embodiment described with reference to FIGS. 2 to 8, the same reference numerals are given to the same components and the description thereof is omitted, and the differences will be described.

[0070] As shown in Fig. 9(a), on the stepped surface 8z of the outer peripheral surface 8x of the tip 8a of the injector 8 of the in-mold coating injection device 1 according to the modified example, a flange portion 8w is provided on the tip surface 8y side with respect to the heat insulation layer 9 (ceramic sprayed layer) provided on the stepped surface 8z. The outer diameter A of the edge of the flange portion 8w is smaller than the outer diameter B of the surface of the heat insulation layer 9. The outer diameter B of the surface of the heat insulation layer 9 is equal to the hole diameter C of the tip hole portion 11a of the mounting hole 11. Therefore, a gap G is formed between the edge of the flange portion 8w and the tip hole portion 11a of the mounting hole 11 of the upper mold 2b.

[0071] Figs. 10(a), 10(b), and 10(c) show the manufacturing process of the flange portion 8w and the heat insulation layer 9 of the tip 8a. First, as shown in Fig. 10(a), on the outer peripheral surface 8x of the tip 8a of the injector 8, a stepped surface 8z having a smaller diameter than the outer peripheral surface 8x and a flange portion 8w having a larger diameter than the stepped surface 8z and a smaller diameter than the outer peripheral surface 8x are machined by a lathe or the like. Next, as shown in Fig. 10(b), ceramic (for example, zirconia) is sprayed on the stepped surface 8z so as to have a larger diameter than the outer peripheral surface 8x. Thereafter, as shown in Fig. 10(c), the sprayed ceramic is polished (cut) to be flush with the outer peripheral surface 8x, and the ceramic sprayed layer 9 as the heat insulation layer is completed.

[0072] As shown in Fig. 9(a), the outer diameter B of the ceramic sprayed layer 9 is the same as the hole diameter C of the tip hole portion 11a of the mounting hole 11, and the outer diameter A of the edge of the flange portion 8w is slightly smaller than the hole diameter C of the tip hole portion 11a of the mounting hole 11. In the present embodiment, the outer diameter B of the ceramic sprayed layer 9 is 10.000 mm, the hole diameter C of the tip hole portion 11a of the mounting hole 11 is 10.000 mm, the outer diameter A of the edge of the flange portion 8w is 9.994 mm, and a slight gap G of 0.006 mm (6 μm) is formed between the edge of the flange portion 8w and the inner peripheral surface of the tip hole portion 11a of the mounting hole 11. Note that the gap G is not limited to 6 μm and may be in the range of 1 to 9 μm.

[0073] (Function and Effect of Modified Example) Using the injector 8 according to the modified example shown in Fig. 9(a), in order to inject the paint 4 (thermosetting liquid coating agent) into the coating gap 13 between the outer surface of the molding substrate 3 shown in Fig. 2 and the inner surface of the cavity 14 of the upper mold 2b, when the paint 4 (thermosetting liquid coating agent) is injected from the injection port 6 at the tip 8a of the injector 8 shown in Fig. 9(a) into the coating agent reservoir 26, a part of the injected paint 4 (thermosetting liquid coating agent) enters the gap G between the tip hole 11a of the mounting hole 11 of the upper mold 2b and the edge of the flange portion 8w of the injector 8. As shown in Fig. 9(b) and its partial enlarged view Fig. 9(c), the paint 4 (thermosetting liquid coating agent) that has entered the gap G is cured by the heat from the upper mold 2b. Since the paint 4 (thermosetting liquid coating agent) cured in this way functions as a plug Z that closes the gap G, it is possible to prevent the paint 4 (thermosetting liquid coating agent) injected from the injection port 6 from entering the heat insulation layer 9 (ceramic spraying layer) through the gap G.

[0074] Therefore, for example, even when the ceramic is sprayed onto the stepped surface 8z at the tip 8a of the injector 8 so that the ceramic spraying layer 9 becomes a porous and porous structure in order to enhance the heat insulation property of the heat insulation layer 9 (ceramic spraying layer), the paint 4 (thermosetting liquid coating agent) sprayed from the injection port 6 of the injector 8 into the coating agent reservoir 26 can avoid the situation of contacting and biting into the end face of the heat insulation layer 9 (ceramic spraying layer) through the gap G shown in Fig. 9(a), and the mold release becomes easy. In addition, it is possible to avoid the deterioration of the ceramic spraying layer 9 due to the paint 4 entering from the end face of the heat insulation layer 9 (ceramic spraying layer) into the ceramic spraying layer 9. In addition, when the tip 8a of the injector 8 is inserted into the tip hole 11a of the mounting hole 11 provided in the upper mold 2b, the flange portion 8w functions as a cover (protective member) that protects the corner at the lower end of the heat insulation layer 9 (ceramic spraying layer), and it is possible to prevent the situation where the corner at the lower end of the heat insulation layer 9 (ceramic spraying layer) hits the edge of the tip hole 11a and is damaged.

[0075] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications and variations within the scope described in the claims also belong to the technical scope of the present invention.

Industrial Applicability

[0076] The present invention can be used in an in-mold coat injection device for injecting a thermosetting liquid coating agent into a coating gap between a molding base material held inside a heated mold and the inner surface of the mold, and an in-mold coat injection method using the same.

[0077] 1 In-mold coat injection device 2 Mold 2a Lower mold 2b Upper mold 3 Molding base material 4 Thermosetting liquid coating agent (paint) 6 Injection port 7 On-off valve 7d Tip valve part 8 Injector 8a Tip part 8b Middle diameter part 8c Large diameter part 8x Outer peripheral surface 8y Tip surface 8z Step surface 8w Flange part 9 Heat insulation layer (ceramic sprayed layer) 10 Cooling mechanism 10a Cooling water passage 11 Mounting hole 11a Tip hole part 12 Core 13 Coating gap 14 Cavity 26 Coating agent reservoir part G Gap A Outer diameter of the edge of the flange part 8w B Outer diameter of the surface of the heat insulation layer 9 Z Plug formed by curing the paint 4 that has penetrated into the gap G

Claims

1. An in-mold coat injection device for injecting a thermosetting liquid coating agent between the outer surface of a molding base material held inside a heated mold and the inner surface of the mold, comprising: An injector having an injection port and an on-off valve for opening and closing the injection port at its tip, and for injecting the thermosetting liquid coating agent jetted from the injection port between the outer surface of the molding base material and the inner surface of the mold; A heat insulating layer made of a material having a lower thermal conductivity than the material of the tip is provided between the tip of the injector and the mold. The in-mold coat injection device is characterized by this.

2. The in-mold coat injection device according to claim 1, wherein a cooling mechanism is provided in the injector to prevent the thermosetting liquid coating agent inside the injector from curing.

3. The tip of the injector has an outer peripheral surface that is inserted into a mounting hole formed in the mold and a tip surface provided with the injection port, The in-mold coat injection device according to claim 2, wherein the heat insulating layer is provided on the outer peripheral surface of the tip so as to contact the inner peripheral surface of the mounting hole.

4. The in-mold coat injection device according to any one of claims 1 to 3, wherein the thermal conductivity of the heat insulating layer is lower than the thermal conductivity of the mold.

5. The in-mold coat injection device according to any one of claims 1 to 3, wherein the heat insulating layer is a sprayed layer.

6. The in-mold coat injection device according to claim 5, wherein the sprayed layer is a ceramic sprayed layer formed by spraying ceramic.

7. A flange portion is provided on the outer peripheral surface of the tip of the injector, on the tip surface side with respect to the heat insulating layer provided on the outer peripheral surface, The in-mold coat injection device according to claim 3, wherein the outer diameter of the edge portion of the flange portion is smaller than the outer diameter of the surface of the heat insulating layer, and a gap is formed between the edge portion of the flange portion and the mounting hole of the mold.

8. The in-mold coat injection device according to claim 7, wherein the heat insulating layer is porous.

9. An in-mold coat injection method for injecting the thermosetting liquid coating agent between the outer surface of the molding base material and the inner surface of the mold using the in-mold coat injection device according to any one of claims 1 to 3, Heat from the mold is transmitted to the tip of the injector through the heat insulating layer, thereby suppressing heat transfer from the mold to the tip of the injector. An in-mold coat injection method characterized by suppressing the curing reaction of the thermosetting liquid coating agent in the vicinity of the injection port disposed at the tip of the injector and the on-off valve for opening and closing the injection port.

10. An in-mold coat injection method in which the thermosetting liquid coating agent is injected between the outer surface of the molding substrate and the inner surface of the mold using the in-mold coat injection device according to claim 7 or 8, A part of the thermosetting liquid coating agent ejected from the injection port of the injector enters the gap between the mounting hole of the mold and the edge of the flange portion of the injector, and the thermosetting liquid coating agent that has entered the gap is cured by the heat from the mold, thereby preventing the thermosetting liquid coating agent ejected from the injection port from entering the heat insulating layer through the gap. An in-mold coat injection method characterized by this.

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