JP2001038767A - In-mold decorating apparatus for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-mold decorating apparatus for injection molding having a sheet cutter using a heating wire generating no slackening. SOLUTION: In an in-mold decorating apparatus for injection molding equipped with a sheet cutter having a heating wire 63 cutting the decorating sheet continuing to a decorating sheet supply part from the parting surface of a female mold at the position on the side of the decorating sheet supply part of the female mold when a hot platen 60 movable to the position along the parting surface of the female mold is present at the position pressed to the parting surface of the female mold, the sheet cuter is provided under tension between the support members 61 provided to the hot platen 60 in such a state that tension is applied to the heating wire 63 by the spring 63a provided to at least one of the end parts of the heating wires 63. Since the generation of slackening in the heating wire 63 is prevented by the tension of the spring 63a, it can be prevented that the heating wire 63 comes into contact with the mold to generate a short circuit and the decorating sheet can be certainly cut linearly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous injection molding and painting apparatus for forming a picture by bonding and laminating a painting sheet on the surface of a resin molded article in the same step as molding of the resin molded article.

[0002]

2. Description of the Related Art Conventionally, as a method of providing a pattern on the surface of a resin molded product, a sheet with a picture is inserted between the male and female dies of injection molding, the two dies are engaged and the mold is clamped, and then the molten resin is filled into the cavity. In general, a method of injection-filling the inside of the inside and bonding a picture sheet to the surface of a resin molded product is generally performed.

[0003] As a simultaneous injection molding painting apparatus for carrying out such a method, a continuous band-shaped painting sheet unwound from a winding is inserted between the male and female dies, and is placed on the parting surface of the peripheral edge of the cavity surface of the female mold. After fixing the painted sheet with the clamp, insert the hot platen at the position facing the clamped painted sheet to heat and soften the painted sheet, and at the same time, install it on the upstream side (in the sheet conveyance direction) of the hot platen The sheet with the current shot is separated from the sheet with the next shot by cutting the painted sheet over the entire width on the upstream side of the clamp with a sheet cutter made of the heated filaments. It is known to prevent heat and stress from going back to the sheet after the next shot (Japanese Patent Laid-Open No. 6-31595).
No. 0, Japanese Patent Application Laid-Open No. 10-249888, etc.).

[0004]

The injection molding simultaneous painting apparatus of the type described above has a feature that the structure is simpler than a sheet cutter using a cutting blade because a heating wire is used for the sheet cutter. are doing. However,
There is a danger that the heating wire attached in a state of being stretched between the support members is elongated due to heat and becomes slack, and comes into contact with the mold to cause an electric leakage. Further, there has been a problem that the sheet residue easily adheres to the slack heating wire, and the sheet cannot be cut straight, and in the worst case, the sheet cannot be cut.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an injection molding simultaneous painting apparatus having a sheet cutter using a heating wire which does not cause slack. Is to do.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a male mold, a female mold, and a sheet with a picture between the male and female molds to form a cavity in the female parting surface. Conveying means positioned so as to cover, and a hot platen movable to a position along the female parting surface so as to heat and soften the painted sheet upon contact with the female cavity surface,
When the hot platen is facing the female parting surface and is in a position to be heated, the heating plate comprises a heating line which cuts a painted sheet continuing from the female parting surface to the painted sheet supply section at a position on the female painted sheet supply section side. In an injection molding simultaneous painting apparatus comprising a sheet cutter and means for injecting a molten resin into the female and male mold cavities, the sheet cutter comprises a spring provided with a heating wire at at least one of its ends. It is characterized in that it is stretched between supporting members provided on the hot platen in a state where tension is applied by the above.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a simultaneous painting apparatus for injection molding according to the present invention. In the injection molding machine 10, the female mold 20 has a structure in which a vacuum suction hole 21 or a vacuum suction groove is provided so as to be applicable to vacuum suction molding. A part of the shape of the molded product formed by the
It is shaped as The male mold 30 is fixed to a fixed platen 31 and also to a tie bar 40 (a total of four). On the other hand, the female die 20 is fixed to a movable plate 22, and the movable plate 22 is slidably penetrated by a tie bar 40. The vacuum suction hole 21 of the female die 20 is connected to a switching valve 71 via a passage 70, and the switching valve 71 switches the passage 70 between the heating air supply source H and the vacuum pump P. I have. The female mold 20 is provided with a vent 72, and the vent 72 is provided with a leak valve 73 for opening and closing the vent.

In the drawing, reference numeral 60 denotes a hot platen, on which a sheet cutter for cutting the sheet S with a picture is attached. FIG. 2 is a plan view of the hot platen (above FIG. 1, ie, z
As viewed from the axial direction), as shown in the figure, L-shaped support members 61 are respectively protruded from upper portions of both side surfaces of the hot platen 60. A terminal 62 is embedded at the tip, and a heating wire 63 as a sheet cutter is stretched between the terminals 62. The end of the heating wire 63 is wound in a coil shape to form a spring portion 63a, and the heating wire 63 is stretched between supporting members in a state where tension is applied by the spring portion 63a. The spring portion 63 may be formed at any one end, but if it is formed at both ends as shown in the figure, it can better cope with elongation. Here, as the heating wire 63,
A nickel-chromium alloy or the like having an appropriate electric resistance and a diameter of about 0.5 to 1.0 mm is used. Further, a porcelain or glass such as steatite is used for the support member 61 and the terminal 62, and an electric wire 64 passes through the support member 61 in the illustrated example. Power is supplied from the same power source.

FIG. 3 is a plan view of a hot plate to which another sheet cutter is attached. In this example, the spring portion is formed by a member different from the heating wire 63. Specifically, the heating wire 63
Is locked to the insulator 65, and the other end of the insulator 65 is pulled by the spring member 66 and locked to the support member 61.
The material forming the spring member 66 may be the same material as the heating wire 63, or may be another material (carbon steel, phosphor bronze, etc.). Also in this case, the spring members 66 may be provided at both ends of the heating wire 63, or may be provided at only one of them. Electrically, both ends of the heating wire 63 are connected to an electric wire 64 in the support member 61 via a lead wire 67.

In any of the above examples, the support member 61
Is mounted on the upper side of the hot platen 60, but may be mounted on both sides of the upper surface (end surface in the + z direction) of the hot platen 60. In this case, the extension of the heating wire 63 is the same as that shown in FIGS.

The hot platen 60 itself may be a conventionally known one used in a simultaneous painting apparatus for injection molding, for example, a metal or ceramic block-shaped hot plate incorporating an electric heater, or a heat-resistant plate. A so-called sheet-like heating element made of resin or metal may be used. The hot platen 60 may be provided on the surface thereof with a ventilation hole for blowing out compressed air for forming the sheet S with vacuum. Also,
The hot platen 60 may be a non-contact type that heats by radiant heat, or may be a type that heats by contacting a painted sheet. The heating temperature for the non-contact type is about 200 to 400 ° C., and the heating temperature for the contact type is 100 to 120 ° C.
It is about.

Prior to the injection of the resin, the prepainted sheet is preformed. In performing this preforming, first, the front end of the picture sheet S inserted between the male and female molds is held by being sandwiched by the receiving chuck 23, and the picture sheet S is held on the parting surface of the female mold 20 by the sheet clamp 50. The entire peripheral edge of the cavity surface 24 is pressed and fixed, so that the closed space V is formed by the female mold cavity surface 24 and the painting sheet S. Next, the ram 68 of the fluid pressure cylinder for driving the hot platen is actuated to turn on the hot platen 60.
Is inserted between the male and female dies, and the upper end side of the painted sheet S is clamped by the conveying sheet chuck 80, and is brought close to the painted sheet S fixed to the parting surface of the female mold 20, and the heating wire 63 is moved. By bringing the sheet into contact with the sheet S with the picture, the sheet for the current shot and the subsequent sheets for the next shot and thereafter are separated by fusing. As described above, the painting sheet S can be automatically separated from the downstream side by utilizing the movement of the hot platen 60 approaching the female mold 20. Further, since the heating wire 63 is stretched by a spring, the picture sheet S can be cut straight. After the cutting of the painted sheet S is completed in this way, the transporting sheet chuck 80 holding the upper end side of the painted sheet S is returned to a position where heat is not affected. This state is shown in FIG.

As described above, the enclosed space V is formed by the painted sheet S.
Is formed, and after cutting the painted sheet S for the current shot,
While the leak valve 73 is opened, the switching valve 71 opens the passage 7.
0 is connected to a heating air supply source H to supply heating air into the closed space V. Then, the inside of the sealed space V is replaced with air at a predetermined temperature, and is higher than the outside air temperature (room temperature), and the Vicat softening temperature of the painted sheet (JIS K 7206).
After the temperature is lowered, the picture sheet S is heated and softened by the hot platen 60 inserted between the two molds. Then, the leak valve 73 is closed, and the passage 70 is connected to the vacuum pump P by the switching valve 71. By suctioning the air in the closed space V through the vacuum suction holes 21 of the mold 20, the painting sheet S is brought into close contact with the female mold cavity surface 24.

After completing the preforming of the picture sheet S, FIG.
The hot platen 60 is retracted to an external standby position (not shown) between the male and female molds, and the piston 91 is actuated by the fluid pressure cylinder 90, as shown in FIG. After being combined with the male mold 30 while sliding on the tie bar 40, the molds are clamped.
Is filled with the resin M for forming a flowing product through the male gate 32 to perform injection molding. Then, the injected resin M is solidified,
After bonding and laminating the painted sheet S and the resin molded product,
As shown in FIG. 5, the male and female molds 20 and 30 are opened, and the resin molded product N whose surface is decorated with the picture sheet S is taken out of the mold. The female mold 20 and the male mold 30 are formed of metal such as iron or ceramics.

The above-described injection molding simultaneous painting apparatus is an embodiment of the present invention, and the present invention is not limited only to such a configuration. Other than employing the sheet cutter unique to the present invention as described above, other components can be arbitrarily selected from the components of various known simultaneous injection molding and painting apparatuses, and can be adopted and combined.

As the painting sheet, a sheet having a base material sheet as a minimum element and having been subjected to a decoration treatment by kneading a colorant, printing a pattern, forming a metal thin film, or the like as necessary is used. The base sheet is made of polyolefin resin such as polyethylene, polypropylene, olefin-based thermoplastic elastomer, polymethyl (meth) acrylate, methyl (meth)
Acrylic resin such as acrylate-butyl (meth) acrylate copolymer, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, vinyl chloride resin, polycarbonate resin, polystyrene, ABS
A sheet of thermoplastic resin such as resin or a laminate of two or more different layers selected from these sheets,
The thickness is usually about 20 to 300 μm.

If sufficient adhesion to the injection molded article cannot be obtained on the base sheet or the decoration treatment itself, an adhesive layer is formed on the molded article side. The adhesive is selected according to the combination of the materials for the painted sheet and the molded article. For example, in the case of a combination of a base sheet of a polyolefin resin and a molded product of a polyolefin resin, a chlorinated polyolefin resin (such as chlorinated polypropylene) is used. A two-component curable urethane resin layer is formed on a material sheet, and a chlorinated polyolefin resin layer is formed thereon in this order.

As the painting sheet, both types of a laminate sheet and a 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 constituting the decorative treatment or the adhesive force between the base sheet and the adhesive layer is not peeled off under the use conditions of the molded article. The resin for molding production and the painted sheet are used in an integrated state. 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. Then, only the base sheet is peeled off and removed to leave the picture print or the metal thin film adhered to the molded product side.

The resin in the fluid state injected from the male mold gate is a resin for injection molding, and is actually selected according to the required physical properties of the product, cost and the like. Specifically, polyethylene, polypropylene, polybutene, polyolefin resins such as olefin-based thermoplastic elastomers, acrylonitrile-butadiene-styrene copolymer (ABS), polystyrene resin, acrylonitrile-styrene copolymer, polyvinyl chloride resin, polycarbonate, A resin such as an acrylic resin, which is heated and melted and injected, and cooled to be solidified; a polyurethane resin comprising a polyol and an isocyanate crosslinking agent; an epoxy resin having an amine as a curing agent; an isocyanate; In some cases, an uncured liquid component of a two-component reaction-curable resin such as an unsaturated polyester using a sulfonate, benzoyl peroxide or the like as a curing agent is injected and solidified by a chemical reaction.

[0020]

As described above, according to the present invention,
In the simultaneous injection molding painting apparatus, the sheet cutter has a configuration in which the heating wire is stretched between support members provided on the hot platen in a state where tension is applied by a spring provided on at least one of its ends. Since the heating wire does not sag, it is possible to prevent the danger of the heating wire coming into contact with the mold and leaking electricity, to prevent the adhesion of the sheet residue to the heating wire, and to remove the painted sheet. It can be cut straight and reliably.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view showing an example of a simultaneous painting apparatus for injection molding according to the present invention.

FIG. 2 is a plan view of a hot plate to which a sheet cutter is attached.

FIG. 3 is a plan view of a hot plate to which another type of sheet cutter is attached.

FIG. 4 is a partially cutaway view of an injection molding simultaneous painting apparatus showing a state in which molding resin is injected after preforming of a painting sheet.

FIG. 5 is a partially cutaway view of the simultaneous injection molding painting apparatus showing a state in which both the male and female molds are opened and a resin molded product is taken out after the injection molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injection molding machine 20 Female type 21 Suction hole 22 Movable plate 23 Reception chuck 30 Male type 31 Fixed plate 32 Gate 40 Tie bar 50 Sheet clamp 60 Hot plate 61 Support member 62 Terminal 63 Heating wire 63a Spring portion 64 Electric wire 65 Insulator 66 Spring Member 67 Lead wire 68 Ram 70 Passage 71 Switching valve 72 Vent hole 73 Leak valve 80 Seat chuck 81 Sheet cutter 90 Fluid pressure cylinder 91 Piston S Picture sheet C Cavity M Molding resin N Resin molding V Closed space

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4F202 AA03 AA13 AA15 AA21 AA28 AD05 AD09 AF10 AG03 AK09 CA11 CB01 CB19 CB28 CK83 CN01 CN25 CQ01 CQ07 4F206 AA03 AA13 AA15 AA21 AA28 AD05 AD09 AF10 AG03 JJJJ07 J07 J07 J07

Claims (5)

[Claims] 1. A male mold, a female mold, a conveying means for feeding a painting sheet between the male and female molds and positioning the painting sheet on the parting surface of the female mold so as to cover the cavity, and transferring the painting sheet to the female cavity. A hot platen that can be moved to a position along the female parting surface so as to heat and soften when contacting the surface,
A heating wire that cuts the painted sheet continuing from the female parting surface to the painted sheet supply unit at a position on the female painted sheet supply unit side when the hot platen is facing the female parting surface and is heating the painted sheet. In a simultaneous injection molding and painting apparatus comprising a sheet cutter consisting of a strip and a means for injecting a molten resin into the female and male mold cavities, the sheet cutter has a heating wire attached to at least one of its ends. An injection molding simultaneous painting apparatus characterized by being stretched between supporting members provided on a hot platen in a state where tension is applied by a provided spring. 2. The simultaneous injection molding and painting apparatus according to claim 1, wherein the spring is formed by a part of the heating wire. 3. The heating wire is fixed at both ends to an insulating member.
2. The simultaneous injection molding and painting apparatus according to claim 1, wherein a spring is interposed between the insulating member and the support member. 4. The simultaneous injection-molding and painting apparatus according to claim 1, wherein the supporting member is provided on an upper portion on both sides of the hot platen. 5. The simultaneous injection-molding and painting apparatus according to claim 1, wherein the supporting members are provided on both sides of the upper surface of the hot platen.