JP4293492B2 - Injection molding simultaneous painting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of simultaneous molding decoration in which a decorative sheet is laminated and bonded to the surface of a resin molded product to provide a pattern. Specifically, a decorative sheet that has been softened by heating with a hot platen in advance is a female cavity. The present invention relates to an injection molding simultaneous painting apparatus in which a resin injected into a cavity and a decorative sheet are integrated after vacuum forming on a surface.
[0002]
[Prior art]
Conventionally, as a method of providing a pattern on the surface of a resin molded product, a decorative sheet is inserted between both male and female molds for injection molding, both molds are engaged and clamped, and molten resin is injected into the cavity. And the method of sticking a decorating sheet on the surface of a resin molded product is widely performed. And in the apparatus which implements this method, as seen in, for example, Japanese Patent Publication No. 50-19132, Japanese Patent Publication No. 1-48845, etc., the decorative sheet is preliminarily applied by a non-contact heating hot platen of infrared radiation system. Some are softened by heating and vacuum-molded on the surface of the female mold cavity.
[0003]
In such an injection molding machine using a hot platen, the heat on the hot platen surface is dissipated and leaked to the surrounding space through the space between the hot platen and the sheet clamp (sheet holding frame), so the heating efficiency for the decorative sheet There was a problem of being bad. Therefore, as shown in Japanese Patent Application Laid-Open No. 6-315950, a peripheral holding frame that abuts against the sheet clamp on the male parting surface is provided near the periphery on the heating plate heating surface, and the sheet clamp and There is one in which the decorative sheet is sandwiched between the peripheral holding frame to seal the space between the decorative sheet and the heating plate heating surface, thereby preventing the heat from flowing out due to radiation and diffusion conduction with the external space. In addition, as shown in Japanese Patent Application Laid-Open No. 10-128797, the decorative sheet is crimped onto the female parting surface with a sheet clamp to fix the periphery, and the hot platen heating surface is directly adhered to it, In some cases, the space between the decorative sheet and the hot platen is sealed through a gap corresponding to the thickness of the sheet clamp.
[0004]
[Problems to be solved by the invention]
Any of the above-described injection molding apparatuses has an advantage that the heating efficiency for the decorative sheet is good because the space between the decorative sheet and the hot platen is sealed. However, since the distance between the decorative sheet and the heating plate heating surface, that is, the heating distance is constant, the heating distance cannot be changed for adjusting the heating amount. That is, it is physically impossible for the heating plate to be closer to the decorative sheet than the pre-designed heating distance, and it is possible to move away from the decorative plate, but in that case, the decorative sheet and the heating plate The sealing state between the two is released, and the heat insulation effect falls.
[0005]
The present invention has been made in view of the above-described problems, and the object of the present invention is simultaneous injection molding with good heating efficiency for the decorative sheet and easy adjustment of the heating amount of the hot platen. The object is to provide a picture device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes an injection-molded female mold and a male mold, a sheet feeding device for inserting a decorative sheet between both molds in the mold-open state, and a press inserted between both molds. Injection comprising at least a sheet clamp that presses and fixes the decorative sheet onto the peripheral parting surface of the female cavity, and a heating plate that heats and softens the decorative sheet fixed on the female parting surface in a non-contact state. The simultaneous molding apparatus has a heat insulating plate protruding from the heating plate heating surface toward the female mold side outside the side surface around the heating plate.
[0007]
In the above apparatus, it is more preferable that the heat insulating plate is attached to the heat plate via a position variable mechanism, and the amount of protrusion from the heat plate heating surface of the heat insulating plate tip is variable. .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of an injection molding simultaneous painting apparatus according to the present invention. In this injection molding apparatus 1, the female mold 10 has a structure in which a vacuum suction hole 11 or a vacuum suction groove is provided so as to be applicable to vacuum suction molding, and is combined with the male mold 20 for injection molding. A part of the shape of the molded product formed by the above is shaped as the female cavity surface 12. The male mold 20 is fixed to a fixed platen 21 and is also fixed to a tie bar 22 (four in total). On the other hand, the female mold 10 is fixed to the movable platen 13, and the movable platen 13 is slidably penetrated through the tie bar 22. Further, a sheet cutter 14 for cutting the decorative sheet S and a reception chuck 15 for sandwiching the leading end portion of the decorative sheet S are attached to the side surface of the female mold 10. Furthermore, the female mold 10 is provided with a sheet clamp 16 for pressing and holding the decorative sheet S against the parting surface of the female mold 10.
[0009]
In the figure, reference numeral 30 denotes a heating plate, and a heat insulating plate 31 protruding from the heating plate heating surface toward the female mold side is attached to the outside of the side surface around the heating plate 30. FIG. 2 is a perspective view showing the heat plate together with the female mold. As can be seen from FIGS. 1 and 2, each of the four side surfaces of the heat plate 30 is in contact with each heat insulating plate protruding from the slide groove 32. FIG. A heat insulating plate 31 is attached to be supported by the two rods 33. Then, the heat insulating plate 31 connected to the rod 33 protrudes in the female direction by moving the rod 33 back and forth in the direction (x direction) connecting the female mold side and the male mold side manually or by driving an air cylinder or the like. The amount changes. Thus, the rod 33 slides on the slide groove 32, so that the amount of protrusion of the heat insulating plate 31 from the heating plate heating surface at the tip end portion can be changed. In addition, the position variable mechanism of the heat insulation board 31 is not limited to this. The heat insulating plate 31 may be fixed as long as it protrudes from the surface of the hot platen 30, but it is preferable that the protruding amount is variable as described above. Moreover, in FIG. 1, FIG. 2, etc., although the space | gap part G is provided between the heat insulation boards 31 of each four side surfaces of the heat | fever plate 30, when improving the heat insulation effect more, these space | gap G is not provided, It is preferable that all the heat insulating plates on the four side surfaces are made continuous so as to surround the entire circumference of the heating plate 30 (not shown).
[0010]
As the heat insulating plate 31, a metal having high infrared reflectance such as aluminum or copper, ceramics, or the like is used. More preferably, the outside is coated with a heat insulating layer having heat resistance such as asbestos, foamed ceramics, glass fiber or the like.
[0011]
The heating plate 30 itself may be a conventionally known one used in an injection molding simultaneous painting apparatus, for example, a metal or ceramic block heating plate with a built-in electric heater, or a heat-resistant resin or A metal sheet-like so-called planar heating element may be used. Moreover, the surface of the hot platen 30 may be provided with a vent hole for blowing out the compressed air for vacuum-pressure forming the decorative sheet S. The heating temperature is about 200 to 400 ° C.
[0012]
Prior to resin injection, the decorative sheet S is preformed. When performing this preforming, first, as shown in FIG. 1, the leading end of the decorative sheet S inserted between the male and female molds is held between the receiving chucks 15 to hold the decorative sheet S in the party of the female mold 10. The entire peripheral edge portion of the cavity surface 12 is pressed and fixed to the wrapping surface by the sheet clamp 16 so that the closed space V is formed by the female cavity surface 12 and the decorative sheet S. Next, in a state where the upper end side of the decorative sheet S is sandwiched between the conveying sheet chucks 2, the sheet for the current shot and the subsequent sheets for the subsequent shot are separated by fusing by the sheet cutter 14, and then decorated. The conveyance sheet chuck 2 holding the upper end side of the sheet S is returned to a position where it does not affect the heat. At the same time, the hot platen fluid pressure cylinder that drives the piston 34 is operated to insert the hot platen 30 between the male and female molds.
[0013]
Thus, after the sealed space V is formed by the decorative sheet S and the decorative sheet S for the current shot is fixed to the female mold 10 by the sheet clamp 16, the hot platen 30 inserted between the two molds is used. After the decorative sheet S is heated and softened, the air in the sealed space V is sucked through the vacuum suction hole 11 of the female mold 10 so that the decorative sheet S is sucked and adhered to the cavity surface 12 of the female mold 10 by vacuum forming. Let Further, if necessary, pressurized air forming may be added by blowing heated air from a vent provided on the heating surface of the hot platen 30 at this stage (vacuum / pressure forming). FIG. 3 shows a state at the time when the preforming is completed.
[0014]
FIG. 4 is an explanatory view showing the positions of the hot platen 30 and the female die 10 when the hot platen 30 is inserted between the male and female molds. In the state of the drawing, the heat insulating plate 31 is in the retracted position. When heating the decorating sheet S with the hot platen 30, when the heating amount is reduced, as shown in FIG. 5, the hot platen moving fluid pressure cylinder 35 is slightly operated to turn the hot platen 30 and the female mold 10 into The distance between the female die 10 and the heat plate 30 is covered by increasing the distance of the heat insulating plate 31 and increasing the protruding amount of the heat insulating plate 31. When the heating amount is increased, as shown in FIG. 6, the hot platen moving fluid pressure cylinder 35 is actuated greatly to reduce the distance between the hot platen 30 and the female mold 10, and the heat insulating plate 31 protrudes. By reducing the amount, the gap between the female mold 10 and the hot plate 30 is covered. Thus, the amount of heating can be adjusted without releasing the heat from the hot platen 30 to the surroundings.
[0015]
After the preforming of the decorative sheet S is completed, the hot platen 30 is retracted to an external standby position (not shown) between the male and female molds as shown in FIG. , The female mold 10 with the decorative sheet S in close contact with the male mold 20 is slid on the tie bar 22 and clamped, and then the cavity C formed by both molds 10 and 20 is operated. The molded product forming resin P in a fluid state is filled through the male gate 23 to perform injection molding. Then, the injected resin P is solidified, and the decorative sheet S and the resin molded product are bonded and laminated, and then both the male and female molds 10 and 20 are opened as shown in FIG. The applied resin molded product P ′ is taken out of the mold. The female mold 10 and the male mold 20 are made of metal such as iron or ceramics.
[0016]
The injection molding simultaneous painting apparatus described above is an embodiment of the present invention, and the present invention is not limited to only such a configuration. Other than adopting the above-mentioned hot plate unique to the present invention, the other constituent elements can be arbitrarily selected and adopted from various known injection molding simultaneous painting apparatus.
[0017]
As the decorative sheet, a base sheet is used as a minimum element, and a decorative sheet is used as necessary by kneading a colorant, pattern printing, metal thin film formation, or the like. Base sheet is polyolefin resin such as polyethylene, polypropylene, olefinic thermoplastic elastomer, acrylic resin such as polymethyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, polyethylene terephthalate, polybutylene terephthalate A sheet of thermoplastic resin such as polyester resin such as polyester resin, vinyl chloride resin, polycarbonate resin, polystyrene, and ABS resin, or a laminate of two or more different layers selected from these sheets. It is about 300 μm.
[0018]
When sufficient adhesion with the injection molded product is not obtained on the base sheet or the decoration treatment itself, an adhesive layer is formed on the molded product side of the decorative sheet. The adhesive is selected according to the combination of the decorative sheet and the material of the molded product. For example, in the case of a combination of a polyolefin resin base sheet and a polyolefin resin molded product, a chlorinated polyolefin resin (chlorinated polypropylene, etc.), or in the case of a combination of an acrylic resin base sheet and a polyolefin resin molded product, A two-component curable urethane resin layer and a chlorinated polyolefin resin layer thereon are formed in this order on the material sheet.
[0019]
As the decorative sheet, both types of laminate sheet and transfer sheet can be used. In the case of the laminate sheet type, the adhesive force between the base sheet and the pattern printing or metal thin film layer that constitutes the decoration process, or the adhesive force between the base sheet and the adhesive layer is not peeled off under the use conditions of the molded product. The resin for molding production and the decorative sheet are used as they are integrated. On the other hand, in the case of the transfer sheet type, the adhesive strength between the base sheet and the pattern printing or metal thin film layer is set to such an extent that it can be easily peeled off. After the thin film layer is bonded and integrated, only the base sheet is peeled and removed, and the pattern printing or metal thin film layer is left adhered to the molded product side.
[0020]
The fluid resin injected from the gate on the male mold side is a resin for injection molding, and is actually selected according to the required physical properties, cost, etc. of the product. Specifically, polyolefin resins such as polyethylene, polypropylene, polybutene, olefinic thermoplastic elastomer, acrylonitrile-butadiene-styrene copolymer (ABS), polystyrene resin, acrylonitrile-styrene copolymer, polyvinyl chloride resin, polycarbonate, A resin such as an acrylic resin is used, heated and melted, injected, cooled and solidified, a polyurethane resin composed of a polyol and an isocyanate crosslinking agent, an epoxy resin containing an amine as a curing agent, an isocyanate, an organic In some cases, an uncured liquid composition of a two-component reaction curable resin such as an unsaturated polyester using sulfonate, benzoyl peroxide or the like as a curing agent is injected and solidified by a chemical reaction.
[0021]
【The invention's effect】
As described above, according to the injection molding simultaneous painting apparatus of the present invention, by adopting a configuration having a heat insulating plate protruding from the heating plate heating surface toward the female mold side outside the side surface around the heating plate, In the case of the conventional hot platen, the heat on the surface of the hot platen is radiated to the outside by radiation and diffusion conduction through the space between the hot platen and the sheet clamp, so that the heating efficiency for the decorative sheet is poor. Therefore, the heating efficiency for the decorative sheet can be improved.
[0022]
In addition, the distance between the decorative sheet and the heating plate can be changed by adopting a configuration in which the heat insulating plate is attached to the heating plate via a position variable mechanism, and the amount of protrusion from the heating plate heating surface of the insulating plate tip is variable. In this case, the space between the heating plate and the heating sheet can be reliably covered with the heat insulating plate at the peripheral portion of the heating plate.
[Brief description of the drawings]
FIG. 1 is a partially cutaway view showing an example of an injection molding simultaneous painting apparatus according to the present invention.
FIG. 2 is a perspective view showing a heating plate together with a female mold.
FIG. 3 is a partially cutaway view of the injection molding simultaneous painting apparatus at the time when the preliminary molding is completed.
FIG. 4 is an explanatory diagram showing positions of the hot platen and the female die when the hot platen is inserted between the male and female molds.
FIG. 5 is an explanatory diagram when the distance between the heating plate and the female mold is increased.
FIG. 6 is an explanatory diagram when the distance between the hot platen and the female mold is reduced.
FIG. 7 is a partial cutaway view of an injection molding simultaneous painting apparatus showing a state where a molding resin is injected.
FIG. 8 is a partially cutaway view of an injection molding simultaneous painting apparatus showing a state where both the male and female molds are opened and a resin molded product is taken out.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS S Decorating sheet 1 Injection molding apparatus 2 Conveying sheet chuck 10 Female die 11 Vacuum suction hole 12 Cavity surface 13 Movable platen 14 Sheet cutter 15 Reception chuck 16 Sheet clamp 20 Male die 21 Fixed platen 22 Tie bar 23 Gate 30 Heating plate 31 Heat insulation Plate 32 Slide groove 33 Rod 34 Piston 35 Fluid pressure cylinder 40 for moving hot plate Female type fluid pressure cylinder 41 for moving piston Piston

Claims (2)

Female mold and male mold for injection molding, sheet feeding device for inserting a decorative sheet between both molds in the mold open state, and the decorative sheet inserted between both molds on the parting surface at the periphery of the female cavity In the injection molding simultaneous painting apparatus comprising at least a sheet clamp pressed and fixed to a female parting surface and a heating plate that heats and softens the decorative sheet fixed on the female parting surface, a side surface around the heating plate An injection molding simultaneous painting apparatus characterized by having a heat insulating plate that protrudes from the heating plate heating surface toward the female mold side outside. 2. The simultaneous injection molding and painting apparatus according to claim 1, wherein the heat insulating plate is attached to the heat plate via a position variable mechanism, and the amount of protrusion from the heat plate heating surface of the heat insulating plate tip is variable. .

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