JPH11309749A - Hot plate for injection molding in-mold decorating, and apparatus for injection molding in-mold decorating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot plate for injection molding in-mold decorating which can control effective heating temp. to each part of an in-mold decorating sheet to a required value and hardly generates such inconveniences as breakage and wrinkle on the in-mold decorating sheet. SOLUTION: A face heating element 41 with a heat radiating face 42 for heating and softening an in-mold decorating sheet S is provided and an insulating plate 51 is arranged so as to face it to a specified region on the heat radiating face and a number of through-holes with an arbitrary dimension and shape so as to obtain a specified aperture area ratio are formed under an appropriate embodiment of arrangement. The insulating plate 51 is arranged at a position separated by a specified distance from the heat radiating face in parallel with the heat radiating face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative laminated product (product) in which a painted sheet on which a pattern, a character or the like is applied in a mold at the same time as injection molding is integrally adhered and laminated on the surface of an injection resin molded product.
The present invention relates to a hot plate used for simultaneous injection-molding and painting for obtaining the same, and an injection-molding simultaneous painting device provided with the hot plate.

[0002]

2. Description of the Related Art Several methods have been proposed for simultaneous injection molding and painting methods in which a painting sheet is integrally adhered to the surface of an injection resin molded article simultaneously with injection molding.
Most of them are arranged so that all or some of the following steps (a) to (i) are performed in the stated order or permuted, and the steps are sequentially performed or a plurality of steps are simultaneously performed in parallel or in parallel. (Japanese Patent Publication No. 50-19132, Jitsuhei 3
-56344, JP-B-7-41637, etc.).

(A) A sheet supply step of supplying a picture sheet onto a female parting surface used for injection molding. (B) a clamping step of fixing and holding the painted sheet on the female parting surface; (C) A heating softening step of heating and softening the painted sheet with a hot platen or the like.

(D) A drawing step (preliminary forming step) of drawing the painted sheet along the cavity of the female mold by vacuum suction and / or air supply. (E) A mold clamping step of moving one of the female mold and the male mold (usually a female mold) to the other (usually a male mold) to clamp the mold. (F) An injection molding step of injecting and filling a resin (molten resin) in a flowing state from the male mold side into a cavity formed between the female mold and the male mold to perform injection molding.

(G) A mold opening step of separating the female mold and the male mold. (H) A sheet trimming step of separating a portion of the painted sheet to be attached to the injection resin molded body from another portion (excess portion). (I) A take-out step of taking out the laminated product on which the painted sheet is adhesively laminated from both the male and female molds.

[0006] Simultaneously overlapping a plurality of steps means that a plurality of steps are included in one step. For example, in the mold clamping step (e), the painted sheet is divided into a female type and a male type. If it is not fixed and held between them, the clamping step (b) is performed simultaneously with the mold clamping step, and the painted sheet is used in the injection molding step (f). If the stretching is performed by the heat and pressure of the injected molten resin, this means that the stretching step (d) is performed simultaneously with the injection molding step.

[0007] Further, as the painted sheet, either a laminated sheet (laminated sheet) or a transfer sheet is used depending on the product type. In the case of a laminated sheet, the painting is performed as it is by injection molding. That is, all the layers of the sheet are bonded and integrated with the surface of the injection resin molded body to form a decorative layer. On the other hand, when the painting sheet is a transfer sheet, the support sheet of the painting sheet integrated with the surface of the injection resin molded body is peeled off, and only the transfer layer such as the decoration layer remains on the injection resin molding body side. Then, the painting is completed by forming a decorative layer.

In the simultaneous injection molding painting method as described above, a painting sheet is pressed and fixed on a female parting surface by a clamper as a preliminary molding step before the injection molding step, and the painting sheet is heated. It is preferable to carry out a step of stretching in a softened state and closely contacting along the female mold cavity. For this reason, in a normal simultaneous injection molding painting apparatus, the painting sheet is fixed to the female parting surface. And a hot platen for heating and softening the painted sheet.

This will be briefly described below with reference to FIGS. The figure shows an injection molding simultaneous painting apparatus 10 'conventionally used, and this apparatus 10'
As can be clearly understood with reference to FIG. 13, the laminated product P ′ to be obtained is a relatively deep drawn tray-shaped panel having a rectangular shape and a U-shaped cross section in plan view, and the injection resin molded product Pa ′ A picture sheet S (laminate sheet) having, for example, a wood-grained decorative layer is adhered and laminated on the surface of FIG. 12.

The apparatus 10 'has a female mold 12 and a male mold 25 having a concave and convex shape corresponding to the laminated product P', and the female mold 12 has a cavity 13 corresponding to the laminated product P 'to be obtained. A vacuum suction hole 17 as a vacuum suction means, a vacuum suction groove 16, a slit-shaped vacuum suction gap 15, a vacuum suction passage 18, a conduit 19 connected to a vacuum source outside, and the like are provided. On the surface 14, a clamper 80 having a rectangular frame shape or a cross-girder shape when viewed from the X direction in FIG. ,
An O-ring 2 is provided on the outer peripheral side of the parting surface 14.
The O-ring 22 is opposed to the clamper 80.

Then, the sheet S with the picture is transported by the transport chuck 3.
The sheet S, which is supplied to the parting surface 14 of the female mold 12 by sheet supply means such as 1, 32, is pressed and fixed to the parting surface 14 by the clamper 80, and heats the painted sheet S pressed and fixed to the parting surface 14. To soften,
A hot platen 60 is provided. The hot platen 60 has a built-in surface heating element 61 in a casing 63 having an open front surface, and is attached to the tip of a piston rod 67 of, for example, a fluid pressure cylinder (not shown) serving as a hot plate transfer means. The heat radiating surface 6 having a rectangular shape in plan view
2 is lowered from the standby position outside the male and female forming dies (in this case, above the female die 12) in the Z direction in FIG. In the direction of approaching the parting surface 14 (X direction), and is stopped at the opposed heating position (the position in FIG. 11) between the male and female molds (on the parting surface 14 of the female mold 12). At this opposed heating position, the painted sheet S is heated and softened by radiant heat in a non-contact state.

On the other hand, although not shown, the male mold 25 is fixed to a fixed platen to which a nozzle of an injection molding machine is mounted. The male mold 25 has a convex shape corresponding to the laminated product shape. A portion (core portion) 26 is provided, and a runner 27 for injecting the molten resin and a gate 28 connected to the runner 27 are provided therein. The male mold 25 is provided with a recess 29 for accommodating the clamper 20 during the mold clamping and injection molding process as shown in FIG.

[0013]

In the conventional apparatus 10 'having such a structure, as shown in FIG. 11, in the heating softening step, the painted sheet S is heated by the hot platen 60 at the opposed heating position shown in the drawing. In this case, it was found that the following problem occurred.
That is, when the painted sheet S is heated by the hot platen 60 as described above, the injection resin molding P
a ′ (see FIG. 12) (the surface heating element 6
2) are heated substantially uniformly on both the inner and outer peripheral sides. However, in the next stretching step,
As shown by the imaginary line in FIG. 11, the painted sheet S adheres to the flat surface side (the bottom side of the cavity 13) of the injection resin molded body Pa ′ because the laminated product P ′ to be obtained has a deep drawing shape. From the inner peripheral portion Si (the portion shown by hatching in FIG. 14) to be formed, the injection resin molded body P
The outer peripheral portion So to be bonded to the side surface of a ′ (the side peripheral portion of the cavity 13) is stretched more largely, and the outer peripheral portion So is given higher stretchability than the inner peripheral portion Si. That is, heating at a higher temperature is required.

For this reason, the heat radiation surface 6 of the surface heating element 61
2 at a low temperature (for example, 280) suitable for the inner peripheral portion Si, which does not require much stretchability.
When set to (° C), the outer peripheral portion So requiring high stretchability is not stretched sufficiently due to insufficient heating, and is broken or whitened (a phenomenon in which the painted sheet is stretched by the injection resin pressure to cause microcracks). Will occur. In contrast, the heating temperature (heat radiation amount) of the heat radiation surface 62 of the surface heating element 60 is set to a high temperature (for example, 3
When the temperature is set to 20 ° C., overheating of the inner peripheral portion Si causes wrinkles, and a problem such as distortion of the pattern of the decorative layer due to excessive elongation of the sheet. Such inconvenience is more likely to occur as the height difference of the unevenness of the laminated product to be obtained is larger.

Therefore, in order to solve the above-mentioned problems, conventionally, the heat radiation surface is divided into a plurality of blocks (for example, divided into an inner peripheral portion and an outer peripheral portion), and each of these blocks is The heating temperature is controlled in accordance with the amount of stretching required for the painted sheet (for example, see JP-A-6-3159).
50, etc.), and a heating temperature adjusting member made of a material having a different thermal conductivity is partially attached directly to the surface of the surface heating element (see, for example, JP-A-5-96568). A heating temperature adjusting member of a different material is directly attached to the surface of the surface heating element (see, for example, Japanese Patent Application Laid-Open No. 7-290501), so that the painted sheet is heated at a high temperature so as to face the heat radiation surface of the surface heating element. (A part that needs to be heated to a high temperature) by installing a shielding plate (mask) that is hollowed out and opened only the part corresponding to the part, and radiates heat rays only to the high-temperature heating part of the painted sheet and heats it (for example, 6-2
No. 4741) and the like are proposed.

However, in the above-described apparatus, when the heating temperature distribution pattern is complicated, that is, when it is necessary to divide the heating element into a large number of blocks, the surface heating element and its heating temperature control system become complicated and cost is reduced. Disadvantageous. Further, in the above-mentioned one, it is difficult to select the material and shape of the heating temperature adjusting member itself, which is disadvantageous in cost, and the heating temperature adjusting member or the adhesive for sticking it to the surface of the surface heating element is not used. It was susceptible to heat damage, and was liable to be deformed, deteriorated or desorbed, and thus lacked durability.

Further, in the above-described apparatus, the high-temperature heating section of the painted sheet is heated to the maximum, while the non-high-temperature heating section (low-temperature heating section) is hardly heated. The temperature difference from the low-temperature heating section is large,
In addition, the effective heating temperature for the painted sheet changes discontinuously at the boundary between the two. For this reason, thermal stress is generated around the boundary between the high-temperature heating section and the low-temperature heating section, and the painted sheet is likely to be torn and to be wrinkled.

The present invention has been made in order to solve the conventional problems as described above, and it is an object of the present invention to make it possible to manufacture it at a relatively low cost and to have excellent durability.
The effective heating temperature for each of the high-temperature heating section and the low-temperature heating section of the painted sheet can be adjusted to a desired value,
Accordingly, it is an object of the present invention to provide a hot plate for simultaneous injection molding and an apparatus for simultaneous injection molding, in which problems such as tears and wrinkles are less likely to occur in the painting sheet.

[0019]

SUMMARY OF THE INVENTION In order to achieve the above object, a hot plate for simultaneous painting with injection molding according to the present invention is basically a surface heating device having a heat radiation surface for heating and softening a painting sheet. A shielding plate is installed so as to face a specific region on the heat radiation surface, and a large number of through-holes having arbitrary dimensions and shapes are provided on the shielding plate so as to obtain a predetermined opening area ratio. Are formed in the form of an array.

Here, the hot platen according to the present invention is more specifically provided with a surface heating element for radiantly heating the non-contact sheet on the painting sheet, a fluid pressure cylinder such as an air cylinder, a rack and pinion or a screw feed. The sheet is transported to the painting sheet heating position by a hot plate transporting means such as a linear transport mechanism, a carriage mechanism running on a guide rail, or the like. The position of the hot plate at the time of heating the painted sheet is usually on the female parting surface,
Before supplying the painted sheet on the female parting surface, there is a case where the heating softening and stretching process of the painted sheet are performed,
In this case, the position at the time of heating the painted sheet is on a dedicated mold having the same shape as the female mold (the cavity and parting surface).

As the surface heating element provided in the heating plate,
Heating a ceramic plate or metal plate with a heating wire such as a nichrome wire installed in it, heating by induction heating or dielectric heating by an electromagnetic field, heating by flowing a heat medium such as high-temperature steam into a buried pipe, Heating with a buried heat pump may be used, and the painted sheet is heated and softened by radiation of heat rays from the surface of the surface heating element. Alternatively, the surface heating element may be formed of a sheet-like resistor, and may be energized and heated to radiate heat rays.

Further, as the surface heating element, one having a uniform heating temperature (radiation amount of heat rays) density distribution on the entire heat radiation surface is used, and by installing the shielding plate, the effective heating temperature for the painted sheet is reduced. A distribution may be provided, or the heat radiation surface may be divided into a plurality of blocks, and the heating temperature may be controlled for each of those blocks, so that the effective heating temperature for the painted sheet may be roughly reduced. By providing the shielding plate so as to face a specific region of at least one of the plurality of blocks, the effective heating temperature for the painted sheet has a more precise surface distribution. You may do so.

The shape of the heating plate and the surface heating element may be a flat plate, a female die, or the same shape as the female die (cavity) for performing the heating softening and stretching steps of the painted sheet. For example, it may be a three-dimensional type corresponding to a parting surface or a cavity shape of a dedicated molding die, for example, in a “K” shape when viewed from the side (for example, Japanese Patent Application Nos. 8-290660 and 10-38592). Etc.).

On the other hand, as the shielding plate, a metal plate having good heat ray reflectivity and heat resistance is used. The material, in particular,
Metals such as aluminum, silver, copper and gold are preferred. Alternatively, iron-based metals such as carbon steel and stainless steel, and titanium alloys can also be used. Since gold, silver, and the like are expensive, a thin film of gold, silver, or the like may be formed on the surface of an iron-based metal or the like by plating, vacuum evaporation, or the like. The thickness of this shielding plate is 0.3 to 2.0 m
m is preferable.

The dimensions, shape and arrangement of the through holes formed in the shielding plate are set so as to obtain a predetermined opening area ratio (open area per unit area). That is, the shape of the through hole may be any shape such as a circle, a triangle, a rectangle, a hexagon, and a star, and its dimensions (diameter, diagonal length, etc.) can be appropriately set. From the viewpoint of controlling the heating temperature, it is preferable that the diameter or the diagonal length be about 0.5 to 5 mm in a circular or regular polygon. In addition, a commercially available inexpensive punching metal, expanded metal, mesh, or the like can be used as the shielding plate.

The ratio of the total opening area of the through holes (the total area ratio of all the through holes to the outer area of the entire shielding plate) is 1 to 50%.
The degree is preferred. In this case, the opening area ratio (opening area per unit area) may be uniformly determined for each area when the shielding plate is divided into several small areas, or the opening area ratio between each of the small area sections may be determined. May be different. That is, when the shielding plate is installed at a portion facing the low-temperature heating portion of the painted sheet on the heat radiation surface,
On the side closer to the high-temperature heating portion of the painted sheet (for example, on the outer peripheral side) of the shielding plate, the opening area ratio is increased to increase the amount of radiated heat rays to increase the effective heating temperature for the painted sheet. Is preferred.

Further, it is preferable that the shielding plate is installed in parallel with the heat radiation surface of the surface heating element at an appropriate distance, preferably about 5 to 50 mm. In this case, the shielding plate may be attached to the heat radiation surface via a spacer made of, for example, ceramics having heat resistance, ceramics, mica, asbestos, metal, or the shielding plate may be a hot plate. For example, it may be attached to a casing or the like covering a surface other than the heat radiation surface of the surface heating element via a bracket made of heat-resistant metal or ceramic.

On the other hand, an injection molding simultaneous painting apparatus according to the present invention comprises a hot plate on which the above-mentioned shielding plate is installed, and both male and female molds, preferably on the parting surface of the female mold. While supplying the painted sheet, the supplied painted sheet is pressed and fixed on the parting surface by clamping means, and the painted sheet is heated and softened by the hot platen, and is vacuumed into the female mold cavity by vacuum suction means or the like. Stretched so as to be closely adhered along with each other, and thereafter, the male and female molds are clamped to form a resin in a flow state from an injection molding machine between the male mold and the female mold and the male mold. After injection filling into the molding cavity, and after the resin is solidified, the mold opening of the male and female molds is performed, and a laminated product in which the painted sheet is bonded and laminated from the male and female molds is taken out.

When performing the heating and softening step of a painted sheet with an injection molding simultaneous painting apparatus having a hot plate on which a shielding plate is installed as described above, first, for example, the hot plate is connected to both male and female molds. From the outside standby position, on the female parting surface where the painting sheet is pressed and fixed by the clamping means,
The sheet is moved to the painting sheet heating position (opposing heating position). When the hot platen is moved to the opposed heating position, the shielding plate installed on the hot platen is arranged at a position facing the low temperature required heating portion of the painting sheet. In this case, the heat rays radiated from the heat radiation surface of the surface heating element of the hot plate reach the painting sheet through the through-hole formed in the shielding plate, but are reflected or blocked in portions other than the through-hole. It does not reach the picture sheet.

Accordingly, the effective heating temperature of the painted sheet by the surface heating element with respect to the low temperature required heating portion is proportional to the opening area ratio of the through hole, and the high temperature required in the other area where the shielding plate does not face. The temperature is lower than that of the heating unit. Here, if the shielding plate is not formed with a through-hole, the high-temperature heating portion of the painted sheet is heated to the maximum while the low-temperature heating portion facing the shielding plate is hardly heated. As the temperature difference between the high-temperature heating section and the low-temperature heating section increases, the effective heating temperature for the painted sheet changes discontinuously at the boundary between the two, and the boundary between the high-temperature heating section and the low-temperature heating section changes. Thermal stress is generated around the part, and the painted sheet is easily torn and wrinkled. However, by forming the through holes as described above, the effective heating temperature of the painted sheet with respect to the low-temperature heating portion is adjusted to an appropriate temperature. This makes it possible to prevent defects such as tears and wrinkles from occurring in any of the high-temperature heating portion, the low-temperature heating portion, and the vicinity of the boundary between them.

In this case, the shielding plate is not directly attached to the heat radiating surface but is arranged in parallel at a predetermined distance from the heat radiating surface via, for example, a spacer made of a heat-resistant material. By doing so, heat damage can be reduced and durability can be improved. In addition, the opening of the through hole between the small sections of the shielding plate such that the opening area ratio increases toward the side (for example, the outer peripheral side) of the shielding plate that is closer to the high-temperature heating portion of the painted sheet. By making the area ratio different, the closer to the high-temperature heating part of the low-temperature heating part of the painting sheet, the higher the radiation amount of heat rays is, and the higher the effective heating temperature is, the higher the heating temperature of the painting sheet becomes. The effective heating temperature for the low-temperature heating section and the high-temperature heating section is changed more continuously, so that thermal stress is less likely to occur near the boundary between the high-temperature heating section and the low-temperature heating section of the painted sheet. The occurrence of tears, wrinkles, and the like can be suppressed more effectively.

In addition to the above, it is also preferable that the shielding plate is movable in a direction along the heat radiation surface, or is detachably attached to an arbitrary position in the direction along the heat radiation surface. It is mentioned as an embodiment. By doing so, one hot plate with a shielding plate,
It can be used when manufacturing several types of laminated products, and the range of application is expanded. In addition, if a plurality of types of shielding plates having different dimensions, opening area ratios, through hole arrangements, etc. are prepared in correspondence with a plurality of types of laminated products to be obtained, the shielding plates can be replaced. In this way, it is possible to cope with the production of multiple types of laminated products with the same heating plate and surface heating element, and to keep the cost of the entire equipment low.
Production efficiency is improved.

In the simultaneous injection molding painting apparatus of the present invention,
The male and female molds are made of metal such as iron or ceramics, and are provided with small holes (vacuum suction holes or the like) for vacuum suction or compressed air supply as necessary. In addition, the female mold is composed of an aggregate of a plurality of divided parts (so-called nested structure)
Then, a slit-shaped gap may be formed between adjacent divided portions, and the gap may be used as a vacuum suction hole to perform vacuum suction. The male mold is provided with a runner for injecting the resin in a flowing state and a required gate. The number, position, shape and the like of the gates can be freely set in consideration of the shape and the like of the product to be obtained.

Further, a clamping means is provided for fixing and holding the picture sheet on the female parting surface. As the clamping means, a frame-shaped or double-girder-shaped holding plate or the like can be used, and the driving thereof can be performed by using a molding driving force such as a mold clamping operation or by using the power of an ejector pin driving mechanism. In addition to this, it is possible to provide a separate driving means such as a fluid pressure actuator.

As a method for supplying a sheet with a picture, an unwinding and winding system (roll / roll system) in which a long continuous belt-shaped sheet wound in a roll shape is run between an unwinding roll and a winding roll. Alternatively, the leading end of a long continuous belt-shaped sheet wound in a roll shape is gripped by a transport chuck or the like and supplied onto a female parting surface, and cut every single shot to form a sheet-like sheet. Either a feeding method or a method of feeding a single sheet by a robot or the like can be adopted.

The painted sheet is composed of a base sheet and a decorative layer laminated thereon, and is a laminated sheet (laminated sheet) used as a final product while keeping the base sheet in close contact with the molded product, or Once the painted sheet and the molded article are integrated, any transfer sheet that peels off the substrate sheet (support sheet) while leaving only the decorative layer (transfer layer) on the molded article side can be used.

In the case of the laminated sheet, a thermoplastic resin such as polyolefin resin such as polyethylene and polypropylene, polyvinyl chloride, acrylic resin, polystyrene, ABS resin, polycarbonate resin and polyester resin is used as the base sheet. Can be. The thickness of the base sheet is usually about 20 to 500 μm. As the decorative layer, a printed pattern, colored or transparent coating, a metal thin film (partly or entirely), or a functional layer such as a hard coating film, an anti-fog coating film, or a conductive layer can be used.

In the case of the transfer sheet, it is for transferring a transfer layer composed of a pattern layer or the like once formed on a releasable support sheet to another transfer target, and is not necessary on the support sheet. A release layer may be provided according to the conditions, and the transfer layer includes a release layer, a decorative layer, an adhesive layer, and the like, and layers other than the decorative layer are selected as necessary. The decorative layer is selected from a pattern layer, a metal thin film layer (part or entire surface) or a functional layer such as a hard coating film, an anti-fog coating film, or a conductive layer.

The support sheet is made of nylon 6, nylon 6
A flexible thermoplastic resin film such as a polyamide resin such as No. 6 or the like, a polyolefin resin such as polyethylene or polypropylene, polyvinyl chloride or the like, or a laminate thereof is preferable. The resin for injection molding is a liquid or fluid state obtained by heating and melting a thermoplastic resin such as ABS (acrylonitrile-butadiene-styrene copolymer) resin, polystyrene, polyvinyl chloride, acrylic resin, polycarbonate resin, etc. Or, two-part curing type, catalyst curing type resin, for example, urethane resin, polyester resin, uncured liquid such as epoxy resin and the like can be used conventionally known materials for simultaneous injection molding and painting, It is selected according to the required physical properties and cost.

[0040]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are a longitudinal sectional view and a transverse sectional view showing a heating and softening step of an injection molding simultaneous painting apparatus using a hot plate according to a first embodiment of the present invention. The laminated product P to be obtained by the simultaneous painting apparatus for injection molding 10 of the present embodiment has a substantially rectangular window portion Pw at the center and a U-shaped cross section, as can be clearly understood from FIGS. It is a long and narrow trapezoidal panel having a height (depth) and width increasing toward the lower portion (front side in the figure), and is formed by bonding and laminating a painting sheet S on the surface of an injection resin molded body Pa. Here, as the above-mentioned sheet S with a picture, here, a base sheet made of an acrylic resin obtained by adding acrylonitrile-butadiene rubber and an aliphatic alcohol-based lubricant to a methyl methacrylate-butyl methacrylate copolymer (having a thickness of 12
5 μm) and a decorative layer laminated thereon by a gravure printing method (a binder of a 1: 1 weight ratio mixture of an acrylic resin and a vinyl chloride-vinyl acetate copolymer, and a red pigment, carbon black, and a pigment of graphite). Laminated laminate consisting of a pattern layer printed with an ink and an adhesive layer (vinyl chloride-vinyl acetate copolymer), and used as a final product while the base sheet is tightly integrated with the injection molded resin Pa A sheet (laminated sheet) is used. The decorative layer (pattern layer) is composed of a combination of a wood grain pattern formed by combining three colors of a pattern plate and a logo mark composed of characters as shown in FIG. 3A, and the adhesive layer has a screen ruling of 40. Line / cm gravure solid printing plate (plate depth 60μm)
Is a layer having a thickness of 2 μm formed twice (by two-color gravure printing).

Injection molding simultaneous painting apparatus 10 of this embodiment
Has substantially the same basic configuration as the injection molding simultaneous painting apparatus 10 'shown in FIGS. 10 to 12 described above, and has a female mold 12 and a male mold having an uneven shape corresponding to the laminated product P to be obtained. Although not shown, the bottom of the female mold 12 is fixed to a movable platen, and the female mold 12 is horizontally moved by a ram or the like of a fluid pressure cylinder (X direction in FIG. 1), in other words. , To move toward and away from the male mold. In the present embodiment, the female die 12 is a movable die as described above and is configured to move in the horizontal direction. However, the present invention is not limited to this. It is also possible to adopt a form in which one of them is vertically opposed and one of them is moved in the vertical direction.

The female mold 12 has a nested structure composed of a plurality of split molds.
2, a cavity 13 corresponding to the laminated product is formed. At the bottom of the cavity 13, a projection 13d corresponding to the window Pw of the laminated product P to be obtained is provided so as to project therefrom. A parting surface 14 is formed on the outer peripheral side of the cavity 13. Around the cavity 13 on the parting surface 14, an annular continuous cross-section rectangular sheet fixing suction groove 16 for vacuum suction of the painting sheet S is formed so as to surround the cavity 13, and the sheet fixing is performed. A predetermined number of vacuum suction holes 17 are opened in the suction groove 16 at a predetermined pitch.

A slit-like gap 15 serving as a vacuum suction hole is formed between the split dies in the female mold 12. The slit-shaped gap 15 is opened at a boundary between a rounded corner (R) forming a corner of the cavity 13 and a plane part following the corner.
The reason why the slit-shaped gap 15 is opened at the boundary portion is that the boundary portion is most likely to have a trace of a line remaining on the laminated product P due to the existence of the gap 15 used as a vacuum suction hole. This is because it is an inconspicuous part.

The vacuum suction hole 17 opened in the sheet fixing suction groove 16 and the slit-shaped gap 15 are connected to the outside through a vacuum suction passage 18 and a conduit 19 formed in the female die 12. In this embodiment, the vacuum suction hole 17, the sheet fixing suction groove 16, and the slit-shaped gap 1 are connected to a vacuum pump (not shown).
5. The vacuum suction means is constituted by the vacuum suction passage 18, the conduit 19, an external vacuum pump, and the like.

Further, the parting surface 1 of the female mold 12
On the outer peripheral side of 4, an annular mounting groove 23 in which an O-ring 22 is mounted is provided. The O-ring 22 hermetically seals the cavity 12 and the outside when a rectangular frame-shaped or cross-girder-shaped clamper 20, which will be described later, is pressed against the parting surface 14 of the female die 12 with the painting sheet S interposed therebetween. Acts as a barrier to On the other hand, the male mold is not shown, but is basically fixed to a fixed plate on which a nozzle of an injection molding machine is mounted, similarly to the conventional one. A convex portion (core portion) corresponding to the shape of the laminated product P is provided, and a runner for injecting the molten resin and a gate connected thereto are provided inside the convex portion (core portion).

The female die 12 is provided with a clamper 20 having a rectangular frame shape or a cross girder shape when viewed from above, for pressing and fixing the picture sheet S to the parting surface 14 thereof. The clamper 20 is driven by a drive mechanism (not shown) by four connecting rods 24 (see FIG. 10) slidably fitted in through holes provided near four corners of the female mold 12 to form a partition of the female mold 12. It can move forward and backward in the direction perpendicular to the bearing surface 14.

In addition to the above configuration, a hot platen 40 is provided to heat and soften the picture sheet S pressed and fixed to the parting surface 14 by the clamper 20. The hot platen 40 is attached to the tip of a piston rod 47 of, for example, a fluid pressure cylinder (not shown) serving as a hot platen transferring means. With the heat radiation surface 42 facing the female mold 12 side, outside the male and female molds (here, above the female mold 12).
1 is moved straight down along the Z direction in FIG. 1 and is also moved in the direction approaching the parting surface 14 of the female mold 12 (X direction). At the opposed heating position (position shown in FIG. 1) on the parting surface 14 of the mold 12, the painted sheet S is heated and softened by radiant heat in a non-contact state at the opposed heating position. .

More specifically, as shown in FIG. 5 in addition to FIGS. 1 and 2, the hot platen 40 has a front surface (the female mold 12 side) inside a casing 43 having an opening. A heating element 41 is incorporated. This surface heating element 41 is, for example,
This is a type in which a ceramic plate or a metal plate forming the heat radiation surface 42 is heated by a heating wire such as a nichrome wire provided therein, and radiation of heat rays from the front surface (heat radiation surface 42) of the surface heating element 41. Heats and softens the painted sheet S. In the hot platen 40 of the present embodiment, the heat radiation surface 42 has four blocks (the first block 42-1 from the upper side,
It is divided into a second block 42-2, a third block 42-3, and a fourth block 42-4), and the heating temperature can be controlled for each of those blocks.

Here, as described above, the laminated product P to be obtained has a U-shaped cross section, and has an elongated trapezoidal shape in which the height (depth) and width become larger toward the lower side in FIG. 3 and the like. Therefore, the painted sheet S to be adhered and laminated thereon is required to have higher stretchability toward the lower side. For this reason, in the present embodiment, the part of the painted sheet S pressed and fixed to the parting surface 14 to be bonded to the upper part and the intermediate part of the laminated product P (the injection resin molded body Pa) is subjected to heat radiation. Face 4
2, the first block 42-1, the second block 42-2, and the third block 42-3 heat at a relatively low temperature (the temperature of the heat radiation surface is, for example, about 280 ° C.). On the other hand, the portion of the painted sheet S to be bonded to the lower part of the laminated product P (the injection resin molded body Pa) is relatively high temperature (the temperature of the heat radiation surface is low) by the fourth block 42-4. (For example, about 320 ° C.).

However, even the portion of the painted sheet S to be bonded to the lower part of the laminated product P should be bonded to the flat surface side (the bottom side of the cavity 13) of the injection resin molded body Pa. Since the inner peripheral portion Su (corresponding to the hatched portion in FIG. 3A) is a flat surface, the side surface of the injection resin molded body Pa (the cavity 1).
The outer peripheral portion Sv to be bonded to the (3 side peripheral portion) does not require high stretchability, and when heated at a relatively high temperature as described above, there may be a problem such as wrinkles. Further, on the contrary, since the logo mark is formed by characters on the inner peripheral part Su, if the picture sheet is too elongated, the characters are distorted, which is inconvenient. Rather, it is a location that must be heated to a lower temperature than the surroundings.

Therefore, in the present embodiment, the shielding plate 51 is provided at a position of the fourth block 42-4 of the heat radiation surface 42 facing the inner peripheral portion Su of the painting sheet S. The shielding plate 51 is made of a rectangular stainless steel plate having a thickness of about 0.5 mm, and is located at a position closer to the third block 42-3 at the center of the heat radiation surface 42 in the width direction of the fourth block 42-4, for example. With four corners supported by four columnar spacers 45 made of ceramic, metal, or the like having a property, they are attached in parallel at a distance of about 5 mm from the heat radiation surface 42 (42-4).

In the shielding plate 51, a large number of through-holes 71 having arbitrary dimensions and shapes are formed in an appropriate arrangement so as to obtain a predetermined opening area ratio (opening area per unit area). ing. Specifically, FIG.
As shown schematically in FIG. 2, circular through holes 71 having a diameter of about 1 mm are formed in a rectangular array at intervals of about 5 mm. The dimensional shape of the through-hole is not limited to the above-mentioned circular one, and for example, a square through-hole 72 may be formed as in a shielding plate 52 shown in FIG.
Alternatively, an equilateral triangular through-hole 73 may be alternately reversed and formed in an array, as in a shielding plate 53 shown in FIG.
It can take any form, and its spacing and arrangement form,
It can be set appropriately according to molding conditions and the like.

In the simultaneous injection molding painting apparatus 10 of the present embodiment having the hot platen 40 as described above, when performing the simultaneous injection molding painting, the painting sheet S is placed on the parting surface 14 of the female mold 12. At the same time, the supplied painted sheet S is pressed and fixed to the parting surface 14 by the clamper 20, and the painted sheet S is heated and softened by the hot platen 40 as described later. A vacuum suction means comprising a suction groove 16 and a slit-shaped vacuum suction gap 15 extends the female mold cavity 13 so as to be in close contact therewith. Thereafter, the male and female molds are closed, and an injection molding machine is formed. Is injected from a male mold into a molding cavity formed between the female mold 12 and the male mold, and after the resin has solidified, Perform mold opening of both molds, decorative sheet S is to take out the laminated product P which is adhesively laminated from the male and female both molds.

Here, when performing the above-mentioned heating and softening step of the painted sheet S, first, for example, the painted sheet S is pressed and fixed by the clamper 20 from the standby position outside the male and female forming dies. It is moved to the painting sheet heating position (opposing heating position) on the parting surface 14 of the female mold 12 (see FIGS. 1 and 2). When the hot platen 40 is moved to the opposed heating position, the shielding plate 51 installed on the hot platen 40 is arranged at a position facing the inner peripheral portion Su, which is a low-temperature required heating portion of the painting sheet S. Will be.
In this case, the heat rays radiated from the heat radiating surface 42 of the surface heating element 41 of the hot platen 40 directly reach the painted sheet S except for the portion where the shielding plate 51 faces.

On the other hand, the portion where the shielding plate 51 faces, that is, the inner peripheral portion S under the painting sheet S
The heat ray from the fourth block 42-4 of the heat radiation surface 42 reaches u only through the through-hole 71 formed in the shielding plate 51, and is not reflected or reflected in a portion other than the through-hole 71. It is cut off and does not reach the sheet S with pictures. Therefore, the effective heating temperature of the inner peripheral portion Su of the painted sheet S, which is required to be heated at a low temperature, by the surface heating element 41 is proportional to the opening area ratio of the through-hole 71, and the shielding plate 51 faces. The temperature is lower than that of the outer peripheral portion Sv, which is the other high-temperature heating portion.

Here, when the through-hole 71 is not formed in the shielding plate 51, the outer peripheral portion Sv of the painting sheet S which is required to be heated at a high temperature is heated to the maximum while the shielding plate 5 is heated.
1 is hardly heated, the temperature difference between the high-temperature heating section and the low-temperature heating section increases, and the painted sheet S at the boundary between them. The effective heating temperature changes discontinuously, and thermal stress occurs around the boundary between the high-temperature heating section and the low-temperature heating section, which breaks into the painted sheet and easily causes wrinkles, etc., as described above. By forming the through-holes 71, the inner peripheral portion Su serving as a low-temperature required heating portion of the painted sheet S is formed.
It is possible to adjust the effective heating temperature of the sheet S to an appropriate temperature, whereby the outer peripheral portion Sv serving as a high-temperature required heating portion, the inner peripheral portion Su serving as a low-temperature required heating portion of the painted sheet S,
In addition, defects such as tears and wrinkles can be less likely to occur around the boundary between them.

In this case, the shielding plate 51 is not directly attached to the heat radiating surface 42 (42-4), but is provided at a position separated from the heat radiating surface 42 by a predetermined distance. By arranging them in parallel with each other via 45, heat damage is less likely to occur and durability is improved. by the way,
In the above embodiment, the size, shape, and spacing of the through holes 71 are uniform, but instead, for example, FIG.
As schematically shown in (B), the closer to the high-temperature heating portion of the painting sheet S (for example, the outer peripheral side indicated by the arrow E) of the shielding plates 54 and 55, the more the openings of the through holes 74 and 75 are opened. By making the opening area ratios of the through holes 74 and 75 different between the small sections of the shielding plates 54 and 55 so that the area ratio becomes large, the high temperature of the low temperature heating portion of the painting sheet S is required. The closer to the heating section, the higher the effective heating temperature because the amount of radiation of the heat rays is increased and the effective heating temperature of the painted sheet S with respect to the low-temperature heating section and the high-temperature heating section is more continuously increased. Therefore, thermal stress is less likely to be generated around the boundary between the high-temperature heating section and the low-temperature heating section of the painted sheet S, and the occurrence of tears, wrinkles, and the like is more effectively suppressed.

FIGS. 8 and 9 show a second embodiment of a hot plate for simultaneous painting with injection molding according to the present invention. The hot platen 40 'of the illustrated embodiment has a built-in surface heating element 41 in a frame-like casing portion 44 having an open front surface (the female mold 12 side), similarly to the hot platen 40 of the above-described embodiment. The heat radiation surface 42 of the heating element 41 has four blocks (a first block 42-1, a second block 42-2, and a third block 42-2 in order from the top).
3, a fourth block 42-4), and the heating temperature can be controlled for each of the blocks. The fourth block 42-4 of the heat radiation surface 42
The same shielding plate 51 as that of the first embodiment is arranged in parallel at a position facing the inner peripheral portion Su of the painted sheet S at a distance of about 5 mm from the heat radiation surface 42-4.

Here, the shielding plate 51 can be moved in the direction along the heat radiation surface 42 and can be detachably attached to an arbitrary position in the direction along the heat radiation surface 42. Has become. That is, in the hot platen 40 of the present embodiment, the central portions of the left and right ends of the shielding plate 51 are attached and fixed to a pair of left and right mounting plates 85, 85 arranged on both sides of the casing portion 44 via the brackets 84, 84. I have. On the other hand, on both sides of the casing portion 44,
Mounting grooves 81 having a T-shaped cross section are formed.
Sliders 82, 82 each having a rectangular plate shape are slidably fitted in the mounting grooves 81, 81, respectively. Then, bolts 86, 86 from the outer surface side of the mounting plates 85, 85 pass through the side openings of the mounting grooves 81, 81 and slide the slider 8.
2 and 82, the mounting plates 85 and 85 and the sliders 82 and 82 are tightened and fixed so as to clamp the side end upper and lower pieces 44a of the casing 44.

As described above, the shielding plate 51 can be moved in the direction along the heat radiation surface 42 (vertical direction in the case of FIG. 8) and at any position in the direction along the heat radiation surface 42. Can be detachably attached to the heating plate 40 provided with the shielding plate 41. By changing the position of the shielding plate 41, several kinds of laminated products (for example, the position of a logo mark) Different products) can be used, and the applicable range is expanded. In addition, if a plurality of types of shielding plates having different dimensions, opening area ratios, through hole arrangements, etc. are prepared in correspondence with a plurality of types of laminated products to be obtained, the shielding plates can be replaced. Just
The same heating plate and surface heating element can be used to manufacture a plurality of types of laminated products, so that the cost of the entire equipment can be reduced and the production efficiency can be improved.

[0061]

As can be understood from the above description, the hot plate for simultaneous injection molding and the simultaneous painting apparatus for injection molding provided with the same according to the present invention can be manufactured at a relatively low cost. The effective heating temperature of each of the high-temperature heating section and the low-temperature heating section of the painted sheet can be adjusted to a desired value, and therefore, the painted sheet is less likely to be broken or wrinkled.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a heating softening step of an injection molding simultaneous painting apparatus having a hot plate according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the device shown in FIG.

FIG. 3 is a view showing a laminated product to be obtained by the apparatus shown in FIG. 1;

FIG. 4 is a perspective view showing the laminated product shown in FIG. 3 upside down;

FIG. 5 is a plan view (A) and a bottom view (B) of the hot platen of the first embodiment.

FIG. 6 is a diagram which is used for describing a shielding plate provided on the hot platen according to the first embodiment.

FIG. 7 is a diagram which is used for describing another preferred example of the shielding plate.

FIG. 8 is a plan view (A) and a bottom view (B) showing a hot plate of a second embodiment according to the present invention.

FIG. 9 is a perspective view showing a hot plate of a second embodiment according to the present invention.

FIG. 10 is a longitudinal sectional view showing the overall configuration of a conventional simultaneous injection molding painting apparatus having a hot platen.

FIG. 11 is a longitudinal sectional view for explaining a heating softening step of the apparatus of FIG. 10;

FIG. 12 is a longitudinal sectional view for explaining an injection molding process of the apparatus of FIG. 10;

FIG. 13 is a perspective view showing a laminated product to be obtained by the apparatus of FIG.

FIG. 14 is a view showing the relationship between the hot platen and the painted sheet in FIG. 10;

[Description of Signs] S Painting Sheet 10 Injection Mold Simultaneous Painting Apparatus 12 Female Die 13 Cavity 14 Parting Surface 40 Hot Plate 41 Surface Heating Element 42 Heat Radiation Surface 51-55 Shielding Plate 71-75 Through Hole

Claims (9)

[Claims] 1. A surface heating element having a heat radiation surface for heating and softening a painted sheet, a shielding plate is provided so as to face a specific area on the heat radiation surface, and a predetermined opening is formed in the shielding plate. A hot plate for simultaneous injection molding and painting, wherein a large number of through-holes having arbitrary dimensions and shapes are formed in an appropriate arrangement so that an area ratio can be obtained. 2. The simultaneous painting with injection molding according to claim 1, wherein the shielding plate is installed at a position separated from the heat radiation surface by a predetermined distance in parallel with the heat radiation surface. Hot plate. 3. The hot plate for simultaneous injection-molding and painting according to claim 1, wherein an opening area ratio of the through hole is different between the small section areas of the shielding plate. 4. The simultaneous painting with injection molding according to claim 3, wherein an opening area ratio of the through holes in the shielding plate increases toward an outer peripheral side of the heat radiation surface. Hot plate. 5. The heat radiation surface is divided into a plurality of blocks so that a heating temperature can be controlled for each of the blocks, and at least one of the plurality of blocks is specified. The hot plate for simultaneous injection molding and painting according to any one of claims 1 to 4, wherein the shielding plate is provided so as to face the region. 6. The hot plate for simultaneous injection-molding and painting according to claim 1, wherein the shielding plate is movable in a direction along the heat radiation surface. 7. The heat shield according to claim 1, wherein the shield plate is attached to the heat radiation surface via a spacer.
6. The hot plate for simultaneous painting with injection molding according to any one of claims 5 to 5. 8. The method according to claim 1, wherein the shielding plate is detachably attached to an arbitrary position in a direction along the heat radiation surface. Hot plate for simultaneous painting with injection molding. 9. A hot plate according to any one of claims 1 to 8, and both male and female molds, and a painted sheet is supplied onto the parting surface of the female mold, and the supplied painted sheet is provided. Is pressed and fixed on the parting surface by clamping means, and the painted sheet is heated and softened by the hot platen, and is stretched by vacuum suction means or the like so as to be in close contact with the female mold cavity. The molds of both molds are clamped, and the resin in a fluid state from the injection molding machine is injected and filled from the male mold into a molding cavity formed between the female mold and the male mold, and after the resin is solidified. An injection molding simultaneous painting apparatus, wherein the mold opening of the male and female molds is performed and a laminated product on which the painting sheet is adhesively laminated is taken out from the male and female molds.