JPH1170543A - Method and apparatus for in-mold decorating injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for injection molding and simultaneously decorating for continuously molding without strain of a decorated pattern in a decorated sheet, positional deviation of the pattern from a resin molding, wrinkle, breakage or the like and by scarcely bringing about external appearance fault of a product even when the molding to be obtained has a deeply drawn shape. SOLUTION: The method for injection molding and simultaneously decorating comprises the steps of heating to soften a decorated sheet S by a first heating platen of a flat plate type, orienting it to a shape similar to a cavity 13 of a female mold 12, then heating to soften the sheet S by a second heating platen 40 of a curved polygonal mold of a similar shape one size smaller than the cavity 13 in a non-contact state, and orienting it along the cavity 13 of the mold 12 until it is brought into close contact with the cavity 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method in which a painted sheet is integrally adhered to the surface of an injection molded resin article in a mold at the same time as injection molding to obtain a molded article on which patterns, characters, etc. are applied. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous painting apparatus and method, and more particularly, to an improved hot plate used to heat and soften a painted sheet before stretching (preforming) the painted sheet effectively.

[0002]

2. Description of the Related Art There have been proposed a number of simultaneous injection molding painting methods in which a painting sheet is integrally adhered to the surface of an injection resin molded article in a mold at the same time as injection molding. Is designed so that all or some of the following steps (a) to (j) are performed in the order described, or the order of the steps is changed, and the steps are sequentially performed or a plurality of steps are simultaneously performed in parallel or in parallel.

(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 stretching step (preliminary molding step) of stretching the picture sheet along the cavity surface 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 into the cavity from the male mold side to perform injection molding. (G) A mold opening step of separating the female mold and the male mold. (H) A trimming step of separating a portion of the painted sheet to be attached to the injection molded product from another portion (unnecessary portion). (I) a step of taking out the injection-molded product to which the painting sheet is adhered from the male and female molds.

[0005] Simultaneously performing a plurality of steps simultaneously 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.

[0006] As the painting 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, 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 product to form a decorative layer. On the other hand, when the painted sheet is a transfer sheet, the support sheet of the decorative sheet integrated with the surface of the injection resin molded product is peeled off, and only the transfer layer such as the decorative layer is placed on the injection resin molded product side. Painting is completed by leaving it as a decorative layer.

In the simultaneous painting method for injection molding as described above, the heating softening step and the stretching step are usually inseparably integrated, and these steps are described in JP-B-63-6339 and JP-A-63-6339. As seen in Japanese Unexamined Patent Publication No. Hei 6-315950, etc., a painted sheet pressed and fixed to a female parting surface with a flat platen heating plate (a heating plate having a flat heating surface portion) is used. After being softened by heating from above or while being softened by heating, the above-mentioned painted sheet is stretched along the female mold cavity by vacuum suction or the like (conventional example), and is slightly smaller than the shape of the female mold cavity. Prepare a plug made of an elastic body, and after heating this plug, press the painted sheet into the female mold cavity with this plug while pressing it against the painted sheet to soften it by heating. In order along with it (conventional example), methods have been adopted such.

[0008]

However, in the case where the heating softening step and the stretching step are performed using a flat-plate type hot plate as in the above-mentioned conventional example, the shape of the molded product to be obtained is particularly high. In the case of a deep drawn shape such as a large uneven shape or a bow shape, as the painted sheet is stretched by vacuum suction or the like and drawn into the female mold cavity,
The part of the painted sheet that is drawn into the cavity gradually moves away from the flat platen hot plate and is cooled by a female mold that is lower in temperature than the painted sheet, so that it is not sufficiently stretched and the cavity (particularly at the bottom of the cavity) (In the vicinity of a corner), and there was a case where it was not possible to adhere along the cavity. If simultaneous painting by injection molding is performed while the painted sheet is lifted out of the cavity in this way, distortion of the picture pattern and misalignment between the picture pattern and the molded body may occur, and in extreme cases, the picture sheet may be wrinkled or torn. There is also.

[0009] Further, as in the above-mentioned conventional example, in the case where the painted sheet is pushed into the female mold cavity with a heated plug made of an elastic material having a size smaller than that of the female mold cavity, the heated mold is heated. The plug on the back side of the painted sheet (the side of the adhesive layer that is bonded to the injection resin molding)
Since the heating and softening step and the stretching step are performed while being in contact with the sheet, the adhesive layer of the painted sheet is taken by the plug, and during mass production (at the time of continuous molding), it starts to become tacky and the plug becomes In some cases, the subsequent steps could not proceed and continuous molding was impossible. In addition, since the heated plug comes into contact with the painted sheet, it does not reach the point where the plug sticks to the painted sheet, but a delicate contact trace of the plug remains on the back side of the painted sheet, and the painted sheet is transparent or translucent. In such a case, a trace of contact of the plug may be seen from the product surface side, resulting in poor appearance.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to appropriately heat and soften a painted sheet even if a molded article to be obtained has a deep drawing shape. It can be stretched along the female cavity, so that the picture sheet does not suffer from distortion of the picture pattern, displacement between the picture pattern and the resin molded product, wrinkles, tears, etc. It is another object of the present invention to provide a method and apparatus for simultaneous painting by injection molding, which makes it possible to perform continuous molding by making the appearance of the product less likely to occur.

[0011]

Means for Solving the Problems In order to achieve the above-mentioned object, the simultaneous painting method for injection molding according to the present invention basically comprises heating and softening a painted sheet with a first platen of a flat plate type. The painted sheet stretched to a shape approximating the cavity of the female mold, and then stretched to a shape approximating the cavity, is passed through a second hot plate of a curved surface / polyhedron type having a similar shape slightly smaller than the cavity. In the non-contact state, the material is further softened by heating, and is stretched until it comes into close contact with the cavity of the female mold.

More specifically, a sheet supply step of supplying a painted sheet onto a female parting surface, a clamping step of pressing and fixing the painted sheet onto the female parting surface by clamping means, A first heat-softening step of heating and softening the painted sheet pressed and fixed by the clamp means with a first platen of a flat plate type; and after or in parallel with the heating softening step, the painted sheet is removed from the female mold. A first stretching step of stretching to a shape approximating the cavity, and a curved surface / polyhedron having a similar shape slightly smaller than the cavity on the painted sheet stretched to a shape approximating the cavity by the first stretching step. A second heating and softening step of further heating and softening the painted sheet by bringing the second hot plate of the mold close so as not to contact the second heating plate; A second stretching step in which the painted sheet is further stretched until it adheres along the cavity after or in parallel with the forming step, and one of the female mold and the male mold is moved to the other side to perform mold clamping. A mold clamping step of forming a cavity between the molds, an injection molding step of performing injection molding by injecting and filling a fluid resin into the cavity, a mold opening step of separating the female mold and the male mold, Taking out the injection-molded product to which the sheet is adhered from the female mold.

In the simultaneous injection-molding and painting method of the present invention, in the second heating softening step and the second stretching step, the second hot platen is moved by the amount of stretching of the painting sheet (to the inner side of the female mold cavity). It is preferable to advance the female mold cavity in the depth direction in accordance with the amount of drawing in).

[0014] Further, an injection molding simultaneous painting apparatus according to the present invention is for carrying out the above-mentioned method, and comprises a female mold and a male mold which are arranged to face each other so that one can be moved to the other side. Clamp means which is movable in a direction perpendicular to the female parting surface, and presses and fixes the painted sheet against the female parting surface,
A first platen of a flat plate type for heating and softening the picture sheet pressed and fixed by the clamp means, a vacuum suction means for extending the picture sheet along the cavity of the female mold, A second hot plate of a curved surface / polyhedron type having a similar shape slightly smaller than the cavity, for further heating and softening the painted sheet stretched to a shape similar to the cavity of the mold, and the female mold and the male mold Resin injection means for injecting and filling a resin in a flow state from the male mold side into a cavity formed between the resin mold and the male mold.

In a preferred embodiment of the simultaneous injection molding and painting apparatus of the present invention, the hot plate transfer means for moving the second hot plate forward and backward in two directions, a direction perpendicular to the parting surface of the female die and a direction parallel thereto. Be provided.

In the method and apparatus for simultaneous painting by injection molding according to the present invention having the above-described structure, the first flat plate type
The hot plate and the second hot plate of the curved surface / polyhedron type are sequentially used to heat and soften the entire portion of the painted sheet which enters the cavity continuously and in a non-contact state, and the softened sheet is moved along the cavity along the cavity. Since it is made to stretch until it adheres tightly, even if the molded product to be obtained is in a deep drawing shape, the distortion of the picture pattern on the painted sheet, as in the case of using only the flat type hot plate of the conventional example described above. Therefore, the displacement between the pattern and the resin molded product, wrinkles, tears, etc. do not occur, and, as in the case where the painted sheet is pushed into the female cavity with the heated plug of the conventional example, the plug is There is no such a situation that the sheet cannot be continuously formed due to sticking to the painting sheet, and furthermore, there is no problem that a fine contact mark of the plug remains on the back side of the painting sheet and the appearance is poor, and Forming the foil-decorating can be done properly and reasonably and quickly the.

The hot plate used in the method and apparatus of the present invention, in particular, the curved / polyhedral second hot plate is preferably a non-contact heating type using radiant heat or dielectric heating. The plate-shaped first heating plate may be of a contact heating type. In addition, the first platen of the flat plate type can use a conventional one as it is, and the second platen of the curved surface / polyhedron type has, for example, a flexible sheet type heater having a heating surface portion. It can be easily manufactured by forming with.

In a preferred aspect of the present invention, the curved plate / polyhedral second platen can be moved in two orthogonal directions so as to approach the painted sheet drawn into the female mold cavity. For example, a hot plate transferring means constituted by an air cylinder or the like is used, and the second hot plate is adjusted by the hot plate transferring device to an amount of extension of the painted sheet (amount drawn into the female cavity). The female mold cavity is advanced in the depth direction.

In the present invention, the male and female molds are made of metal such as iron or ceramics, and provided with small holes (vacuum suction holes or the like) for vacuum suction or compressed air supply as necessary. Alternatively, the female mold is constituted by an aggregate of a plurality of divided portions (in a so-called nested structure), a slit-shaped gap is formed between each divided portion, and vacuum suction is performed using this gap as a vacuum suction hole. You may.

The painting sheet may be supplied in a required amount (one shot each) from the state of a long continuous belt-like sheet wound in a roll shape, or a sheet sheet cut to a predetermined size in advance. May be supplied. Further, in order to supply a painted sheet consisting of a strip-shaped sheet (the next shot portion) or a single sheet, between a female mold and a male mold arranged opposite to each other, the unwinding machine and the winding machine are used to remove the strip-shaped sheet. A roll / roll system in which one shot is continuously supplied, or a system in which the robot is transported by a robot (manipulator) or the like equipped with a suction plate or the like for holding the sheet with a picture, may be used. The roll / roll method is recommended from the aspect of properties.

In addition, a clamp means is provided for fixing and holding the painting sheet on the female parting surface. As the clamping means, a frame-shaped holding plate or the like can be used, and the driving thereof can use a molding driving force such as a mold clamping operation or the power of an ejector pin driving mechanism. This is achieved by separately providing a driving means such as a fluid pressure actuator.

The painting sheet is composed of a base sheet and a decorative layer laminated thereon, and is used as a final laminated product (laminate sheet) which is used as a final product while the base sheet is closely adhered to the molded product. 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 polyvinyl chloride, acrylic, polystyrene, ABS resin, polycarbonate, polyester, polypropylene and polyethylene can be used as the base sheet. The thickness of the substrate sheet is usually 20 to 500
It is about μm. As the decorative layer, printed pattern, colored or transparent coating, metal thin film, or hard coating, anti-fog paint,
A functional layer such as 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. 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
For example, a thermoplastic resin film having flexibility such as polyamide 6, polyolefin such as polyethylene or polypropylene, polyvinyl chloride, or the like, or a laminate thereof is preferable.

As the resin for injection molding, ABS (acrylonitrile-butadiene-styrene copolymer) resin,
Thermoplastic resins such as polystyrene, polyvinyl chloride, acrylic, and polycarbonate that have been heated and melted to be in a liquid or fluid state, or two-part curable and catalyst-curable resins, for example, uncured resins such as polyurethane and polyester Materials that are conventionally known for simultaneous painting with liquid injection molding can be used, and are selected according to the required physical properties and cost of the product.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of an injection molding simultaneous painting apparatus for carrying out the simultaneous injection molding painting method according to the present invention, and FIG. 2 shows a front side of a molded article P to be obtained by the method and apparatus of the present embodiment. Shows the appearance.

The molded product P to be obtained has a convex deep drawing shape having a relatively large difference in elevation, as can be understood by referring to the injection molding process shown in FIG. It is composed of a thin rectangular box-shaped trapezoidal portion Pa and a convex portion Pb having an inverted bottomed cylindrical shape protruding upward, and the entire surface thereof is decorated with the painting sheet S. Has become. Note that the trapezoidal portion Pa of the molded product P has a length a of about 150 mm, a width b of about 100 mm, and a height c of about 20 m.
m, the height d is about 100 mm and the width e is about 70 mm.
mm and the height f is about 60 mm.

Injection molding simultaneous painting apparatus 10 of this embodiment
Has a female mold 12 and a male mold 25 having an uneven shape corresponding to a molded product P to be obtained. The female mold 12 has a bottom fixed to a movable plate (not shown) and has a fluid pressure cylinder. 1 in the horizontal direction (horizontal direction) in FIG.
In other words, it moves forward and backward in a direction approaching and separating from the male mold 25.

In the present embodiment, the female die 12 is movable and moves in the horizontal direction as described above. However, the present invention is not limited to this. It is also possible to adopt a mode in which the female molds are vertically opposed and one of them is moved in the vertical direction. Here, the female die 12 has a nested structure composed of a plurality of split dies, and a slit-shaped gap 1 is provided between the split dies.
The space 5 is formed so as to perform vacuum suction using the gap 15 as a vacuum suction hole as described later.

The female mold 12 has the molded product P
A cavity 13 comprising a shallow concave portion 13a corresponding to the trapezoidal portion Pa and a deep concave portion 13b corresponding to the convex portion Pb is formed, and a stepped parting surface 14 is formed. An annular sheet suction groove 16 is formed around the cavity 13 in the lower portion 14b of the printing surface 14 so as to surround the cavity 13 for vacuum suction of the painting sheet S. A predetermined number of vacuum suction holes 17 are opened at a predetermined pitch.

The vacuum suction hole 17 is connected to an external vacuum pump through a vacuum suction passage 18 and a conduit 19 formed inside the female die 12. The slit-shaped gap 1 formed and communicates with each of the corners of the shallow recess 13a and the deep recess 13b of the cavity 13 and the vacuum suction passage 18.
5, the sheet suction groove 16, the vacuum suction hole 17 opened in the sheet suction groove 16, the vacuum suction passage 18, the conduit 19, an external vacuum pump and the like constitute a vacuum suction means.

Further, the parting surface 1 of the female mold 12
An O-ring 22 is mounted on the upper part 14 a of the fourth member 4 so as to surround the cavity 13. This O-ring 2
2. When a frame-shaped clamper 20, which will be described later, is pressed against the upper portion 14a of the parting surface 14 of the female mold 12 with the painting sheet S interposed therebetween, the cavity 12 and the outside are hermetically shut off. Play a role.

On the other hand, although not shown, the male mold 25 is fixed to a fixed plate on which a nozzle of an injection molding machine is mounted, and the male mold 25 corresponds to the shape of the molded product P. A protruding portion (core portion) 26 is provided to project and fill molten resin from a nozzle of the injection molding machine into a cavity 13 formed between the female mold 12 and the male mold 25. A runner gate is formed. Although not shown, two runner gates are arranged side by side at a predetermined interval along the long side of the molded product P.

The female die 12 is provided with a rectangular frame-shaped clamper 20 for pressing and fixing the picture sheet S to the parting surface 14 thereof. This clamper 2
The upper part 14a of the parting surface 14 of the female mold 12 is driven by a drive mechanism (not shown) by four connecting rods 24 slidably fitted into through holes provided near four corners of the female mold 12. It can move forward and backward in the vertical direction. The male mold 25 is provided with a groove-shaped recess 29 having a depth that allows the clamper 20 to perform a separating operation for releasing the pressing and fixing state with respect to the painting sheet S in a mold clamping state as shown in FIG. Has been established.

In addition to the above-described configuration, the injection molding simultaneous painting apparatus 10 of the present embodiment includes a flat plate-shaped first hot platen 30 for heating and softening the painted sheet S pressed and fixed by the clamper 20; The cavity 1 for further heating and softening the painted sheet S stretched to a shape similar to the cavity 13 of the female mold 12.
The second is a hexahedral type (rectangular parallelepiped) having a similar shape slightly smaller than the deep concave portion 13b and the convex portion Pb of the molded product P to be obtained.
And a hot platen 40.

The first hot platen 30 of the flat plate type has a heating surface portion (the surface portion on the side of the female die 12 in FIG. 1) 32 composed of a flat plate ceramic radiant heater. The female mold 12 can be moved back and forth in two directions, a direction orthogonal to the upper part 14a of the parting surface 14 and a direction parallel to the upper part 14a.

Further, the rectangular parallelepiped second hot platen 40
Five surfaces except one surface of the male mold 25 side are heating surfaces 42, and each of the heating surfaces 42 is constituted by the flat plate ceramic radiant heater. Parting surface 1 of female mold 12
4 can be moved back and forth in two directions: a direction perpendicular to the upper portion 14a and a direction parallel to the upper portion 14a.

In addition, as the above-mentioned painted sheet S, here, a base sheet made of acrylic resin (having a thickness of 125 μm)
A decorative layer (1: 1 weight ratio mixture of acrylic resin and vinyl chloride-vinyl acetate copolymer) laminated thereon by a gravure printing method as a binder resin for the ink; and an adhesive layer (vinyl chloride-vinyl acetate copolymer). And a laminated sheet (laminated sheet) that is used as a final product while the base sheet is tightly integrated with a molded product (injection resin molded product). The decorative layer (pattern layer) has a wood grain pattern formed by combining three colors of a pattern plate, and the adhesive layer has a gravure solid printing plate (screen depth of 60 μm) having a screen ruling of 40 lines / cm. This is a layer having a thickness of 2 μ formed by using the above method.

In the simultaneous injection molding painting apparatus 10 of the present embodiment having the above-described configuration, simultaneous injection molding painting is performed in the following process order. First, as shown in FIG. 3, the sheet S with a picture is supplied onto the female parting surface 14 by a sheet transport mechanism including a transport chuck 51 (sheet supplying step). Is pressed and fixed to the upper part 14a of the parting surface 14 (clamping step).

Subsequently, as shown in FIG. 3, the first flat platen 30 is moved onto the painting sheet S pressed and fixed by the clamper 20, and the first platen 30 is moved to the first platen.
Is heated and softened by the hot platen 30 (first heating softening step). Here, the non-contact heating of the painted sheet S by radiant heat for about 5 seconds at the hot platen surface temperature of 330 ° C. by the first hot platen 30 and then the painted sheet S through the above-described vacuum suction holes 17, slit-shaped gaps 15 and the like. S is vacuum-sucked, and the painted sheet S is stretched to a shape similar to the cavity 13 of the female mold 12 as shown by a virtual line in FIG. 3 (first stretching step).

Next, after the first hot platen 30 is retracted to the original retreat position, the rectangular parallelepiped second hot platen 40 is opposed to the cavity 13 as shown in FIG. While moving to the position, it is advanced along the depth direction of the cavity 13. In this case, the second hot platen is brought close to the painted sheet S stretched to a shape similar to the cavity 13 in the first stretching step so as not to contact the painted sheet S, and the painted sheet S is further irradiated with radiant heat. In addition to the heating and softening (second heating and softening step), the painting sheet S is further stretched in parallel with the second heating and softening step by vacuum suction until the sheet S adheres along the cavity 13 (second stretching step). ).

Here, the vacuum suction is continued while softening the picture-coated sheet S with the second hot platen 40 heated to about 150 ° C. until the picture-sheet S adheres along the cavity 13. As described above, the heating temperature of the second hot platen 40 is set lower than that of the first hot platen 30.
This is because the second hot platen 40 can be closer to the painting sheet S as compared with the case of FIG.

In this case, the second hot platen 40 is
The female plate 12 is advanced in the depth direction of the cavity 13 of the female die 12 according to the amount of extension of the painted sheet S (the amount drawn into the bottom of the cavity 13) by the hot platen transfer mechanism 45, that is, the second It is preferable that the distance between the hot platen 40 and the painting sheet S be substantially constant.

As described above, the first heat softening step and the first
By further performing the second heating softening step and the second stretching step after the stretching step, the painted sheet S that is about to be cooled is reheated and softened by the second hot platen 40. As shown, the painted sheet S is a female mold 1
The second cavity 13 is completely adhered along the cavity 13.

Thus, the sheet S with the picture is
After the second hot platen 40 is completely retracted along the cavity 13 of FIG. 6, the second hot platen 40 is retracted to the original position, and the female mold 12 is moved to the male mold 25 side, as shown in FIG. Then, the mold is clamped to form a cavity 13 between both molds (mold clamping step). Next, a resin in a fluid state (heat-resistant ABS, injection resin temperature 240 ° C, mold temperature 60 ° C) is formed in the cavity 13. ) Is injected and filled to perform injection molding (injection molding step). Thereafter, after the injected resin is solidified by cooling, the female mold 12 and the male mold 25 are separated from each other (mold opening step), and subsequently, the injection molded product P (product) to which the painting sheet S is adhered. From the female mold 12 (removing step).

In the injection molding simultaneous painting apparatus and the injection molding simultaneous painting method using the injection molding simultaneous painting apparatus of the present embodiment having the above-described configuration, the flat plate-shaped first hot platen 30 and the deep recess 13b of the cavity 13 are provided. The whole part of the painted sheet S that enters the cavity 13 is continuously formed by using the rectangular parallelepiped second hot plate 40 having a similar shape slightly smaller than the rectangular cylindrical protrusion Pb of the molded product P to be obtained. In addition, since the painted sheet S is stretched until it comes into close contact with the cavity while being heated and softened in a non-contact state, even if the molded product to be obtained has a deep drawing shape, only the flat plate type hot plate of the conventional example is used. As in the case of using the paint sheet, no distortion of the picture pattern, displacement of the picture pattern and the resin molded product, wrinkles, tears, etc. occur in the painted sheet, and the painted sheet is female with the heated plug of the conventional example. Mold As in the case where the plug is pushed into the tee, there is no situation in which the plug sticks to the painting sheet and continuous molding cannot be performed.Furthermore, delicate contact traces of the plug on the back side of the painting sheet do not appear. There is no inconvenience such as a residual appearance defect, and the simultaneous painting with injection molding can be performed appropriately, rationally and quickly.

In fact, in the injection molding simultaneous painting method and apparatus 10 of the present embodiment, as described above, the painting sheet S adheres along the cavity 13, but as in the above-mentioned conventional example, the flat sheet type first painting method is used. Using only the hot platen 30, the heating softening step and the stretching step are performed by the first hot platen
Is heated at a hot platen surface temperature of about 330 ° C. for about 5 seconds, and then the picture sheet S is vacuum-sucked through the vacuum suction holes 17 and the slit-like gaps 15 and the like, and the picture sheet S is heated by the first heat. The hot plate surface temperature is about 330 by the plate 30
Even if the first hot platen 30 is retracted to the original retracted position after heating at about C for about 5 seconds, the painted sheet S is not sufficiently stretched and the cavity 13 (particularly near the bottom corner) ) May be in a floating state and cannot be brought into close contact with the cavity, and the resulting molded product may be severely distorted in the picture pattern or misaligned between the picture pattern and the molded body. In such a case, wrinkles or tears may occur on the painted sheet, resulting in poor appearance.

Also, as in the above-mentioned conventional example, a plug made of a slightly smaller elastic body similar to the shape of the cavity 13 of the female mold 12 is prepared, and the plug is heated to a surface temperature of 100 ° C. In the case where the plug is used to push the painted sheet into the female mold cavity so as to follow it while pressing and contacting it to soften by heating,
The adhesive layer (Tg = 90 °) was softened and stuck to the plug. When molding was performed continuously for 30 shots, a defect in which the picture sheet and the plug stuck to each other occurred. Further, in the obtained molded product, a portion in which the fine irregularities (contact traces) of the plug were picked up was observed.

[0050]

As will be understood from the above description, according to the method and apparatus for simultaneous painting by injection molding according to the present invention, even if the molded article to be obtained has a deep drawing shape, the painted sheet can be appropriately heated and softened. And can be stretched along the female mold cavity,
Distortion of the pattern on the painted sheet, displacement between the pattern and the resin molded product, wrinkles, tears, etc. do not occur, and excellent effects such as poor appearance of the product are less likely to occur and continuous molding is possible. can get.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an injection molding simultaneous painting apparatus according to the present invention.

FIG. 2 is a perspective view showing the appearance of a molded article to be obtained by the simultaneous injection molding painting apparatus of FIG.

FIG. 3 is a diagram provided for explanation of a clamping step, a first heat softening step, and a first stretching step by the simultaneous injection molding painting apparatus of FIG. 1;

FIG. 4 is a diagram for explaining a second heating softening step and a second stretching step performed by the simultaneous injection molding painting apparatus of FIG. 1;

FIG. 5 is a diagram provided for explanation at the end of a second heating softening step and a second stretching step by the simultaneous injection molding painting apparatus of FIG. 1;

FIG. 6 is a view for explaining a mold clamping step, an injection molding step, and the like of the simultaneous injection molding painting apparatus of FIG. 1;

[Explanation of symbols]

 S Painting sheet P Molded product to be obtained 10 Injection molding simultaneous painting device 12 Female mold 13 Cavity 14 Parting surface 15 Slit-shaped gap 17 Vacuum suction hole 20 Frame-shaped clamper 25 Male mold 30 First hot platen 35 First Hot plate transfer mechanism 40 Second hot plate 45 Second hot plate transfer mechanism

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[Procedure amendment]

[Submission date] September 2, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG. 2

FIG.

FIG. 3

FIG. 6

FIG. 4

FIG. 5

Claims (4)

[Claims] 1. A sheet supply step of supplying a painting sheet onto a female parting surface, a clamping step of pressing and fixing the painting sheet onto the female parting surface by clamping means, A first heat-softening step of heating and softening the pressed and fixed sheet with a first flat platen; and after or in parallel with the heating and softening step, the sheet is approximated to the cavity of the female mold. A first stretching step of stretching to a shape similar to the cavity, and a second surface of a curved / polyhedral type having a similar shape slightly smaller than the cavity in the painted sheet stretched to a shape similar to the cavity by the first stretching step. A second heating softening step of further heating and softening the painted sheet by bringing the hot platen closer so as not to contact the heating board, and after or after the second heating softening step. In parallel with this, the second step is to further extend the painted sheet until it adheres along the cavity.
A stretching step, a mold clamping step of moving one of the female mold and the male mold to the other side and clamping to form a cavity between the two dies, and injecting and filling a fluid resin in the cavity to solidify An injection molding step of performing injection molding at a minimum, a mold opening step of separating the female mold and the male mold, and a removal step of taking out the injection molded product to which the painting sheet is adhered from the female mold. Injection molding simultaneous painting method. 2. In the second heat-softening step and the second drawing step, the second hot platen is advanced in a depth direction of the cavity of the female mold in accordance with a drawing amount of the painting sheet. 2. The method for simultaneous painting by injection molding according to claim 1, wherein: 3. A female mold and a male mold which are arranged opposite to each other and one of which is moved to the other side, and which is movable in a direction orthogonal to the parting surface of the female mold. A clamping means for pressing and fixing the painting sheet to the female parting surface, a first flat platen for heating and softening the painting sheet pressed and fixed by the clamping means, and Vacuum suction means for extending the sheet along the cavity of the female mold,
In order to further heat-soften the painted sheet stretched to a shape similar to the cavity of the female mold, a second hot plate of a curved surface / polyhedron type having a similar shape slightly smaller than the cavity, and the female mold A resin injection means for injecting and filling a resin in a flowing state from the male mold side into a cavity formed between the male mold and the male mold. 4. A hot plate transfer means for moving the second hot plate back and forth in two directions, a direction perpendicular to the female parting surface and a direction parallel thereto. 3. The simultaneous painting apparatus for injection molding according to 3.