JP2000309033A - Method and apparatus for injection molding simultaneous in-mold decoration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize heating of an in-mold decorative sheet and to shorten cycle time. SOLUTION: In performing a sheet feeding process wherein an in-mold decorative sheet S is fed to molds 12 and 25, a premolding process wherein the in-mold decorative sheet S is heated at a heat distortion temp. or higher by means of a heater 70 and it is laid along a cavity face of the mold 12 by evacuation and an adhesive process wherein the molds are clamped and a resin is injected to bond the in-mold decorative sheet and the resin together, before the sheet feeding process, the in-mold decorative sheet S is preheated at a temp. lower than the heat distortion temp. by means of a preheater 4 and after it is preheated by controlling the preheating temp. by means of a heat shielding plate 85 and an electric temp. controlling device, it is fed into a mold. When the in-mold decorative sheets after preheating is fed into the mold, it is pref. covered by a heat insulating hood. In the injection molding simultaneous in-mold decorative apparatus, the in-mold decorative sheet S is carried by means of a chain, etc., and not only a sheet feeding device 5 for feeding the sheet to the mold from the preheating position, but also a preheater 4, a heater 70, a vacuum source 90, etc. are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a painting sheet on which a pattern, a character or the like has been applied in a mold at the same time as injection molding, in close contact with the surface of the injection molded resin article, and laminating or transferring the painting sheet. The present invention relates to an injection molding simultaneous painting method for obtaining a product (product) and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, injection molding simultaneous painting techniques have been carried out in various forms by forming a pattern or the like on the outer surface of a plastic molded article at the same time as molding a plastic molded article using a painted sheet to form a painted molded article. For example, in Japanese Patent Publication No. 50-19132, a female mold provided with a vent hole for vacuum molding is used as a vacuum molding mold, and a sheet with a picture is fed and fixed to the female mold, and then heated and softened by a heater plate. After preforming the painted sheet by vacuum forming and aligning it with the cavity surface of the female mold, the male and female molds are clamped, and the molten resin is injected into the cavity formed by both molds, and then the mold is opened. A method is disclosed in which a molded sheet is taken out to integrate a painting sheet with the surface of the molded article simultaneously with injection molding. Further, for example, in Japanese Patent Application Laid-Open No. 6-315950, a continuous band-shaped picture sheet unwound from a roll is fed between a pair of dies composed of both male and female dies in an open state, and a sheet presser is held on a female parting surface. After fixing the surroundings with the frame and supplying the painted sheet to the female mold, move the heater plate between the two molds from the retracted position outside the mold, and face the painted sheet supplied to the female mold. The painted sheet is heated and softened in a non-contact manner, and the painted sheet is preformed in an injection molding die and along the cavity surface of the female mold.After that, the heater plate is retracted to a retracted position outside the mold, and both molds are removed. A technique is disclosed in which a mold is clamped, a resin is injected into a cavity formed by both molds, and after the mold is opened, the molded article is taken out, thereby simultaneously painting the molded article with a painted sheet simultaneously with molding. In each of these modes, the painted sheet is preformed by an injection molding die, but the heating and softening for the preformed molding of the painted sheet is performed after the sheet is supplied to the molding die.

In Japanese Patent Publication No. 4-42172,
In the form of pre-molding a painted sheet with an injection molding die, a heater plate that reciprocates between a retracted position outside the mold and the inside of the mold to heat and soften the painted sheet is provided with a through hole on its heating surface to paint. An object having a structure capable of adsorbing the sheet and further pressing and fixing the painted sheet to the heating surface by the frame member is used. When the heater plate is in the retracted position, the painted sheet is held on the heating surface, and when moving into the mold, the painted sheet is moved while being held, so that the painted sheet is supplied to the molding die and A technique for softening by heating in parallel is disclosed.

[0004]

However, after supplying a painted sheet at room temperature and below the heat distortion temperature to a molding die for injection molding as disclosed in Japanese Patent Publication No. 50-19132 and JP-A-6-315950. In the form of heating it,
When using a painted sheet having good heat resistance or a thick painted sheet, it takes time to heat the painted sheet, and there is a problem that the cycle time becomes longer and the productivity is reduced. On the other hand, according to Japanese Patent Publication No. 4-42172, the painted sheet can be heated from the time when the heater plate is in the retracted position.
The heating time after the heater plate is moved into the mold can be shortened, but the traces of the ventilation holes provided on the heating surface to adsorb and hold the painting sheet on the heating surface are shaped into the softened painting sheet and the appearance It was sometimes bad. In addition, especially in large size and thick painted sheets, the vacuum for holding the painted sheets by suction may leak or the painted sheets may be turned up.When transporting the softened painted sheets between the male and female molds,
It was difficult to completely suppress deformation and distortion of the painted sheet. Further, when transferring the painted sheet to the female mold which is to be a preforming mold, the heater plate releases suction of the painted sheet by suction from the air hole, and conversely blows out compressed air from the air hole. In addition, since the painted sheet is already heated, when the painted sheet leaves the heated surface in order with a slight time lag, the delivery of the painted sheet may become unstable due to wrinkles in the painted sheet. Was. Further, in the case of a painted sheet having an adhesive layer on the back side, the adhesive layer was sometimes removed to the heater plate side.

[0005] Further, with respect to products for which heating conditions are determined, little consideration is given to temperature changes in the working environment. In some cases, such as when the ambient temperature at that time is too different from that of the current day, the same heating may be used. Under some conditions, the degree of softening by heating varied.

As described above, in the conventional simultaneous painting with injection molding, when the heating and softening of the painted sheet is started on the injection mold for the first time, the cycle time becomes longer by the time required for the heating and softening. Productivity decreased compared to general injection molding. Moreover, the temperature of the sheet surface of the painted sheet when heated and softened for pre-forming can be set for each shot, regardless of whether the intended temperature distribution is made or the temperature distribution is made as uniform as possible. It was very important to make the injection painting simultaneous painting process stable and to obtain a high quality and stable painting painting product.

Accordingly, the present invention provides a method for simultaneous painting by injection molding, which stabilizes the temperature and shape of a painted sheet when it is supplied to a mold, thereby stabilizing the heating of the painted sheet and shortening the cycle time. It is to provide equipment.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for simultaneous painting by injection molding according to the present invention comprises a sheet supplying step of supplying a painted sheet to a pair of molding dies in an open state, A preforming step of heating the sheet to a temperature equal to or higher than the thermal deformation temperature of the sheet by a heating means, and drawing the sheet with a picture along the cavity surface of the mold by evacuation from one mold, and closing the mold to flow into the cavity In the simultaneous injection molding painting method in which the resin in the state is injected and the bonding step of bonding the painting sheet and the resin at least in this order, the sheet preheating is performed before the sheet supplying step of supplying the painting sheet to the molding die. Means for preheating the painted sheet to a temperature lower than the thermal deformation temperature of the sheet by the preheating heater, and controlling the preheating temperature of the painted sheet by the preheating temperature control means. It was like.

As a result, the cycle time can be shortened and the productivity can be improved by shortening the heating time of the painted sheet after the preheated painted sheet is supplied to the mold. Moreover, since the preheating of the painted sheet is set to be lower than the thermal deformation temperature of the painted sheet and the preheating temperature is controlled by the preheating temperature control means,
After preheating to a stable preheating temperature without being preheated to an excessive temperature, the painted sheet can be supplied to the mold. As a result, deformation and distortion of the painted sheet when supplied to the forming die are suppressed, and the painted sheet can be stably supplied to the forming die in shape and temperature. As a result, not only the cycle time is shortened, but also the final heating to a temperature higher than the thermal deformation temperature by the sheet heating means is stabilized. A molded article is obtained.

Further, the method of simultaneous painting by injection molding of the present invention
In the above-described simultaneous injection molding painting method, a heat shield plate is used as a preheating temperature control means, and the heat shield plate is interposed between a preheater located in a position not in contact with the painting sheet and the painting sheet, and the painting is performed. The preheating step is performed while suppressing the temperature rise of the sheet.

As described above, after the painted sheet is preheated to a temperature lower than the heat deformation temperature, the temperature at the time of preheating of the painted sheet is required by interposing a heat shield between the preheater and the painted sheet. Temperature control for suppressing heating can be performed so that the temperature does not rise too much, and a painted sheet preheated at a stable preheating temperature can be supplied to a mold. As a result, deformation and distortion of the painted sheet when it is supplied to the molding die are more reliably suppressed,
The painted sheet can be more stably supplied to the mold in shape and temperature. The preheater is preferably of a non-contact heating type, but can be heated by contact heating until a heat shield plate is interposed.

Further, the method of simultaneous painting by injection molding of the present invention
In addition to any of the above simultaneous injection molding painting methods, when the preheated painted sheet is supplied to the molding die in the sheet supply step, the painted sheet is covered with a heat retaining hood and supplied.

As a result, it is possible to prevent the temperature of the preheated painted sheet from being exposed to the outside air while the preheated painted sheet is supplied to the molding die. Therefore, it is possible to supply to the mold more temperature stable.

[0014] The injection molding simultaneous painting apparatus of the present invention comprises:
Sheet preheating means having at least a preheater and a preheating temperature control means, in order to preheat the painted sheet before being supplied to the pair of molds to a temperature lower than the heat deformation temperature of the sheet;
A sheet supply means for supplying the preheated painted sheet from the preheating position to the forming die, a sheet heating means for heating the preheated painted sheet supplied to the forming die to a temperature equal to or higher than the heat deformation temperature of the sheet, And a preforming means comprising vacuum evacuation means for making the painted sheet follow the cavity surface.

As a result, first, the cycle time is shortened and the productivity is improved by shortening the heating time of the painted sheet after being supplied to the molding die. In addition, since the preheating of the painted sheet is set at a temperature lower than the heat deformation temperature of the painted sheet and the preheating temperature is controlled by the preheating temperature control means, the preheating is performed at a stable preheating temperature without being preheated to an excessive temperature. Thus, the painted sheet can be supplied to the molding die. As a result, deformation and distortion of the painted sheet when supplied to the forming die are suppressed, and the painted sheet can be stably supplied to the forming die in shape and temperature. As a result, in addition to reducing cycle time,
Since the final heating to a temperature equal to or higher than the thermal deformation temperature by the sheet heating means is also stabilized, a stable simultaneous injection molding painting method can be performed, and a high quality painted molded product can be obtained.

Further, the simultaneous injection molding painting apparatus of the present invention
In the above-described simultaneous injection molding painting apparatus, at least a heat shield plate is provided as preheating temperature control means, and the heat shield plate is provided with a heat shielding position between a preheater and a painted sheet located at a position apart from the painted sheet; It is configured to move between the heater and a standby position away from the heater.

As a result, it is possible to control the temperature to suppress the heating so that the temperature of the prepainted sheet at the time of preheating does not rise excessively, and to supply the prepainted sheet preheated at a stable preheating temperature to the molding die. Therefore, the deformation and distortion of the painted sheet when supplied to the forming die can be suppressed more reliably, and the painted sheet can be more stably supplied to the forming die in shape and temperature. The preheater is preferably of a non-contact heating type, but can be heated by contact heating until the heat shield plate moves to the heat shield position.

Further, the simultaneous injection molding painting apparatus of the present invention
In any one of the above simultaneous injection molding painting apparatuses, a heat retaining hood for covering the painting sheet supplied to the molding die from the sheet supply means is provided between the preheater and the molding die.

As a result, it is possible to prevent the temperature of the preheated painted sheet from being exposed to the outside air while the preheated painted sheet is supplied to the molding die. Therefore, it is possible to supply to the mold more temperature stable.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a simultaneous painting method and apparatus according to the present invention; FIG. 1 to FIG. 7 are conceptual diagrams conceptually explaining the injection molding simultaneous painting method and apparatus of the present invention in one form. FIG. 1 is a side view showing the overall configuration of the simultaneous injection molding painting apparatus of the present invention. FIG. 2 is a perspective view showing the periphery of a preheater 4 and a sheet supply device 5 therein. FIG. 3 shows an endless annular chain 50 and a sheet holding chuck 6 in the sheet feeding apparatus.
FIG. FIG. 4 is a partially enlarged cross-sectional view illustrating the endless annular chain 50 and the sheet holding chuck 60 of FIG. 3 and the guide groove 36 provided in the female die 12. FIG.
3 is a partially enlarged cross-sectional view illustrating the operation of the endless annular chain 50 and the sheet gripping chuck 60 of FIG. 3 in relation to the clamper 20. FIG. 6 shows a temperature sensor 81 as one form of preheating temperature control means for the preheating heater 4. FIG. 7 is a side view for explaining a control device 80 used conceptually. FIG. 7 is a side view for explaining a heat shield plate 85 as a preheating temperature control means for the preheating heater 4 and a heat retaining hood 86.

In the apparatus described in these drawings, the molding die used, that is, the injection molding die, has a fixing surface on the female die of the painted sheet which is not a flat surface, but has a male shape in a side view substantially in the shape of "ku". This is a device that can perform “deformation feeding” of a painting sheet, which is fixed to a parting surface 14 that is convexly curved toward the mold side. Of course, in the same apparatus, it is also possible to use an injection mold having a flat parting surface or a concave parting surface toward the male mold side, depending on the shape of the molded product to be manufactured.

In addition, the simultaneous injection molding painting apparatus of the present invention illustrated in these drawings is a preheating means as a sheet preheating means for preheating a painted sheet S before being supplied to a molding die to a temperature lower than a thermal deformation temperature of the sheet. A heater 4 and a heat shielding plate 85 serving as a preheating temperature control means included in the sheet preheating means, a sheet supply device 5 serving as a sheet supply means for supplying a prepainted painted sheet from a preheating position to a molding die; A heater 70 as a sheet heating means for heating the supplied preheated painted sheet S to a temperature equal to or higher than the thermal deformation temperature of the sheet;
The painting sheet S is provided on the cavity surface 13a of one molding die 12.
And a pre-forming means 90 comprising a vacuum evacuation means such as a vacuum pump for moving the apparatus. The sheet supply device 5 has an essential function of performing a sheet supply step of supplying the painted sheet S from the preheating position of the preheating heater 4 of the sheet preheating means to the forming die. A sheet carrying-in step of carrying S into the preheating position facing the preheater 4 from the roll R or the like may be performed. As will be described later, the illustrated apparatus has such a configuration.

In the sheet feeding device 5, when the preheated painted sheet S is supplied to the molding die, the painted sheet S
A plurality of sheet gripping chucks so that the painted sheet S is gripped at least at both ends in the width direction with respect to the transport direction, and the length of both sides in both the width direction and the transport direction of the painted sheet is fixed. The pictorial sheet S is conveyed by a pair of endless annular chains 50 each including 60 and running parallel to each other. The preheater 4 and the heater 70 are devices for preheating and heating the painted sheet by non-contact heating, respectively.

That is, in the simultaneous injection molding and painting apparatus to be described hereinafter (and the simultaneous injection molding and painting method described on the basis of this apparatus), the sheet supply means supplies the prepainted painted sheet S to the molding die when supplying it to the molding die. The painted sheet S was gripped at least at both ends in the width direction with respect to the transport direction of the sheet S, and supplied with the length of the painted sheet in the width direction and the transport direction being constant. With this configuration, even if the painted sheet S is preheated, the width and the length in the transport direction of the painted sheet S are maintained, and thus the deformation and distortion of the painted sheet S when the painted sheet S is supplied to the forming die. An apparatus (and a simultaneous painting method for injection molding) that can reliably prevent the generation and supply the painted sheet to the mold very stably.

It is preferable that the preheating and heating of the painting sheet S be carried out by non-contact heating. However, the simultaneous injection molding painting apparatus described below (and the simultaneous injection molding simultaneous painting method described based on this apparatus) is also used. The preheating and heating of the sheet S with a picture are performed by non-contact heating. As a result, the painting sheet S
Does not fuse to the heater (as a preheating heater or a heating heater) with the adhesive layer or the like, and supply of the painting sheet S to the mold does not become unstable. The apparatus (and method) does not cause poor appearance of the molded article due to the above.

For example, the simultaneous injection molding and painting apparatus of the present invention having the above-described configuration is combined with an existing injection molding machine in the same manner as a conventionally known simultaneous injection molding and painting apparatus. If a molding die corresponding to a desired molded product is prepared, attached to the injection molding machine and subjected to injection molding, a desired painted plastic molded product painted with the painted sheet S can be obtained.

The injection molding simultaneous painting apparatus of the present invention comprises:
It is not limited to the configuration illustrated as an example in FIGS.
Basically, the painted sheet S before being supplied to the pair of molds
Sheet preheating means 4 for preheating the sheet by controlling the preheating temperature to a temperature lower than the thermal deformation temperature of the sheet by a heat shield plate or the like, sheet supplying means 5 for supplying the pre-painted sheet S into the mold from the preheating position, Preheated picture sheet S supplied to the mold
Sheet heating means 70 for heating the painting sheet S to a temperature equal to or higher than the thermal deformation temperature of the painting sheet S, and preforming means 90 comprising vacuuming means for bringing the painting sheet S along the cavity surface of one molding die. The components may be any configuration, and these components or other components can appropriately employ various techniques in a conventionally known simultaneous injection molding and painting apparatus. The sheet preheating means 4, the sheet heating means 70, and the sheet supply means 5 are integrated into one apparatus, and the preforming means 90, which is a vacuum pump or the like for vacuum forming a sheet with a picture, is regarded as a separate apparatus. However, even in this case, the former device and the latter device cooperate with each other in a series of one-cycle operations including preheating, sheet supply, heating, preforming, and injection molding.

Also, the painting sheet S to be used may be a method and an apparatus adapted to the form of preheating, heating, preforming and injection molding in a continuous strip shape, or a single sheet painting sheet may be set from the beginning. Thus, a method and an apparatus adapted to the form of preheating, heating, preforming and injection molding may be used, and the form of the painted sheet is arbitrary.

First, a pair of molding dies (injection molding dies) used in the present invention are, in the form exemplified here, a pair of female dies 12.
And a molding die composed of a male die 25, and is made of a metal such as iron or ceramics. The female mold 12 is fixed to the movable platen 11 of the injection molding machine. The movable platen 11 moves forward and backward in the horizontal direction (Y direction) of the drawing by the ram 9 of the fluid pressure cylinder and the like, so that the female mold 12 approaches and separates from the male mold 25, and the mold clamping state and the mold opening state ( 1). Of course, as for the form of the simultaneous injection molding painting apparatus of the present invention, as shown in FIG. 1, the injection molding machine combined with this apparatus moves vertically in addition to the horizontal type in which the movable mold (female mold 12) moves horizontally. A form corresponding to a vertical type may be used. Here, as shown in FIG. 2, the female mold 12 has a relatively shallow side view roughly "C" -shaped cavity 13 corresponding to the painting molded product to be obtained. 14
Having. The parting surface 14 is the male mold 25 side (Y direction)
It forms a substantially convex (mountain-shaped) curved surface in side view that protrudes from the side surface.
The cavity surface 13a of the female mold 12 has a groove-shaped or hole-shaped ventilation hole 13b for vacuum-forming the painting sheet. Note that the ventilation holes 13b are
May be provided on the parting surface portion inside the O-ring for sealing provided in the above. The vent hole 13b is provided in the preforming means 90.
To a vacuum source such as a vacuum pump, which is a vacuuming means provided outside the mold.

On the other hand, the male mold 25 is fixed to a fixed platen 31 of an injection molding machine as shown in FIG. 1, and an injection nozzle 32 enters the bottom side of the male mold to form both male and female molds at the time of mold clamping. The cavity is filled with a resin in a flowing state by melting or the like. The male mold 25 has a core portion 33 corresponding to the shape of a painted product and a parting surface 34 that is concaved in a “C” shape when viewed from the side. The female mold 12 has
In order to press and fix the painted sheet S against the parting surface 14 of the female die 12, a clamper 20 similar to the parting surface 14 and having a rectangular frame shape in a front view and a substantially "L" shape in a side view is provided. It is. The clamper 20 moves four connecting rods 24 slidably fitted into through holes near four corners of the female mold 12 in a direction perpendicular to the parting surface 14 of the female mold 12 by a driving mechanism (not shown). The drawing sheet is moved forward and backward in the Y direction) to press and fix the painting sheet supplied to the gap between the parting surface and the clamper 20 against the parting surface. The supply of the painting sheet S to the mold is completed by fixing the clamper.

Then, after the sheet supply device 5, which is a component of the simultaneous injection molding painting apparatus of the present invention, carries the painting sheet S to the preheating position by the preheater 4, the preheated painting sheet is transferred to the female mold 12 as described above. On the parting surface 14. The sheet feeding device 5 here includes a base frame 6 as shown in FIG. 1, the base frame 6 is connected and fixed to a movable platen 11 by a connecting member 7, and the base frame 6 is a female mold 1
It moves forward and backward in the left-right direction of the drawing (Y direction) together with the forward and backward movement of the female mold at the time of opening and closing the mold via the rail 3 on the support frame 1 installed on the left side of the 2. FIG.
As shown, a pair of connecting plates 8 which are part of the sheet feeding device 5 are connected below the female mold 12, and each connecting plate 8 supports a pair of sprocket wheels 42 and 43 on the left and right.

On the base frame 6, there is provided an unwinding machine which is loaded with a roll R of the painting sheet S and can apply an appropriate back tension to the painting sheet S. The paper is unwound through the guide roller 48. Then, one shot of the unwound picture sheet S is carried into a position (preheating position) facing the preheater 4. Then, in order to supply the pre-heated picture sheet S using the pair of left and right endless annular chains 50 onto the parting surface 14 of the female mold 12, the base frame 6 uses the pair of left and right sprocket wheels 41, 44, 45. Prepare.
In addition, for example, a pair of sprocket wheels 4
1 is rotated by a rotary drive source (not shown) such as a stepping geared motor to move the endless annular chain 50. The pair of left and right endless annular chains 50 have the same size and shape on the left and right, and the sprocket wheels 41, 4
2, 43, 44, and 45 are entirely wrapped in an L-shape in side view. Of course, the left and right endless annular chains 50
The distance between them (the length in the width direction perpendicular to the transport direction) is constant.

As shown in FIGS. 3 and 4, the endless annular chain 50 is provided with support members 61, for example, at every two pitches. A roller 63 is attached.
Further, at every predetermined pitch (for example, 5 pitches), both ends in the width direction of the one-shot picture sheet S (both ends in the width direction with respect to the conveyance direction, the both ends are parallel to the conveyance direction) on the support member 61. However, the both end portions are usually parallel to the conveying direction, but need not necessarily be parallel to each other, and for example, depending on the shape of the molded product, for example, a single sheet of a painted sheet differs in the width direction length between the front end and the end. A sheet grip chuck 60 for gripping a trapezoidal shape in which both sides in the width direction may be non-parallel to each other is provided. The sheet gripping chuck 60 includes:
In order to be able to hold the pictorial sheet S of one shot length,
The required number is provided only in a specific range of each endless annular chain 50 on both the left and right sides. Then, the sheet feeding device 5 moves the endless annular chain 50 from the feeding position, which is the feeding start position of the pictorial sheet cut for one shot, to the preheating position of the portion where the sheet gripping chuck 60 is provided. Thereafter, the reciprocating motion is performed between the feeding position located on the female parting surface 14. The preheating position at which the painted sheet is preheated on the preheater 4 is a position where the painted sheet is conveyed to some extent from the payout position (see the painted sheet S in FIG. 1), but the payout position is the preheating position as it is. Sometimes.

Then, the endless annular chain 50 grips one shot of the pictorial sheet by the sheet gripping chuck 60 and conveys it onto the parting surface 14 of the female mold 12, and the clamper 20 removes the pictorial sheet. The parting surface 1
4, when the supply of the painted sheet to the forming die is completed, the sheet gripping chuck 60 releases the gripping of the painted sheet, and the endless annular chain 50 rotates in the reverse direction. Return to the original payout position to prepare for the next shot.

As described above, in the method and apparatus for simultaneous painting by injection molding of the present invention exemplified here, the transport mode of the painted sheet is such that the chain 50 is used for the painted sheet transporting means 5 so that it can be moved in the width direction of the painted sheet. Since only the both ends are in contact with each other and the other portions are not in contact with each other, and the leading end of the picture sheet S is not conveyed, the picture sheet does not receive unnecessary tension in the conveyance direction during conveyance. Therefore, even when the prepainted sheet S is supplied after being preheated as in the present invention, the prepainted sheet S which is less than the thermal deformation temperature but is easily stretched from the normal temperature can be extended in both the transport direction and the width direction. The shape can be supplied stably without being stretched in the direction. Moreover,
The surface that fixes the painted sheet to the mold (parting surface 1
There is also an advantage that the sheet S with a picture can be supplied even when 4) is a non-planar surface (but a quadratic curved surface) such as a convex or concave surface. In addition, it is preferable to use a chain as the conveyance mode in which the length of the painting sheet in the conveyance direction (or the length in the width direction) is constant, but it is preferable to use a chain. A long body that is invariable in length and can be bent may be used.

Also, needless to say, in the method and apparatus for simultaneous painting by injection molding of the present invention, the painting sheet conveying means 5 is provided.
May be an object other than the long body which is invariable in length and can be bent. For example, in a mode in which the painting sheet fixing surface is flat and the painting sheet S is conveyed linearly on the plane between the preheating position and the supply position in a form in which the painting sheet fixing surface is flat, a rigid sheet such as a metal plate is used. It may be a long body of invariable length, and may be conveyed by sandwiching and holding both ends of the painted sheet in the width direction from the front and back. Further, needless to say, if the elongation of the painted sheet S can be ignored, the form in which the leading end of the painted sheet S is pulled and conveyed may be used.

The preheater 4 for preheating the painted sheet at the preheating position is not particularly limited as long as it can heat the painted sheet S to a temperature lower than the thermal deformation temperature. For example, conventionally known various heating means such as a heating wire heater, a ceramic heater, a sheet heating element, and a dielectric heater can be used. In addition, the preheater 4 is preferably a non-contact heating, which is also heated by radiant heat, without leaving a trace of contact with the heating surface of the preheater 4 on the painted sheet S or the final painted molded product, Heating is efficient and good. In FIG. 1, the preheater 4 is supported by the base frame 6 so that non-contact heating is performed on the back side of the painted sheet S (the side in contact with the injection resin is the back side and in the case of FIG. Although it is arranged, a preheater may be arranged on the front side or both sides.

The temperature at which the painted sheet S is heated during preheating is as follows:
Heat distortion temperature (4.6 kg specified by JIS K7207)
At f / cm ² bending stress. Hereinafter, it is simply referred to as a heat distortion temperature. ) Is better. This is because when the painted sheet S is heated to a temperature higher than the thermal deformation temperature, when the painted sheet S is transported from the preheating position to the supply position, the shape maintenance of the painted sheet S becomes unstable, and the painted sheet S is stably removed. This is because it is difficult to supply the resin to the mold including the female mold 12 and the male mold 25. The prepainted sheet S is preheated, and even when the prepainted sheet S is transported or preheated, the front and back or the center of the painted sheet S can be freely held only on both sides in the width direction, or the tip of the painted sheet S is conveyed. Even if the temperature is lower than the thermal deformation temperature, the painted sheet S can be supplied stably in shape without causing deformation, distortion, tear, etc. of the painted sheet S. This is particularly true in the case of the latter transport mode in which the painted sheet S is pulled and transported.

In the present invention, in the case of the term "thermal deformation temperature of the painted sheet", if the painted sheet is composed of a plurality of layers [for example, when the substrate is composed of (base sheet / pattern ink layer)] Of these, the thermal deformation temperature of the thickest layer may be targeted. The reason for this is that the behavior of the entire painted sheet being softened and deformed by heat is largely affected by the behavior of the thickest layer.

It is to be noted that the preheating time is set so that the pre-heated sheet S of the next shot is kept in the pre-heating position while the pre-heated softened sheet S is being softened or injection-molded. There is no special cycle time extension due to. Further, the temperature setting of the preheating heater 4 is preferably set so that such a thing can be performed.

That is, the temperature from the preheater 4 of the painting sheet S to the cavity surface 13a of the female die 12 is set to be lower than the heat deformation temperature and as high as possible to room temperature. Usually, the temperature is set to be about 10 to 40 ° C. lower than the heat deformation temperature. In order to keep the finish quality and the cycle time of the molding of the painted molded product for each shot of molding constant, the preheating temperature of the painted sheet S is set so that the sheet temperature when supplied to the molding die is It is preferable to control so as to be a constant value.

In order to control the preheating temperature of the painted sheet S to a constant value, the same molding machine, the same molded product shape (mold shape), the same width, thickness and material of the painted sheet, the same room temperature, In the case of the same preheater 4, the output (or surface temperature) of the preheater 4, the heating time of the preheater 4, and the transfer time of the painting sheet S from the preheater S to the female parting surface 14 are constant. It is fundamental to keep it. The values of the parameters such as the output of the preheater 4 to be set and the temperature of the painted sheet at a desired temperature are determined by conducting experiments in advance in each case.

The output (or surface temperature) of the preheater 4 and the heating time of the preheater 4 were tested as described above using the preheater control device 80 (see FIG. 6) as the preheat temperature control means. The constant value determined in step (1) may be held for each shot. The control device 80 may follow a known technique for adjusting the output of the preheater 4 and the energization time. As described above, in a simple case, the effect of stabilizing the (main) heating and shortening the cycle time by the preheating can be enjoyed only by the preheating temperature control in which only the energization time is ON / OFF controlled when the heater output is fully opened. There is also. Further, in order to keep the conveying time of the prepainted sheet S from the preheater S to the female parting surface 14 constant, the sheet feeding device 5 using the chain 50 conveys the prepainted sheet S at a constant speed at every shot. Good.

It should be noted that variations in various factors (such as variations in the thickness of the painted sheet S, the inflow of outside air, etc.) cause the heater 4 to change.
If it is difficult to accurately maintain the temperature of the painted sheet at a constant value only by keeping the heating time and output of the painted sheet at a constant value, if the preheating heater 4 and the painted sheet S face each other due to trouble during molding, setting of molding conditions, etc. Is longer than the standard value, or immediately after the output of the preheater 4 is changed due to a change in the working conditions such as the type of the painted sheet and the shape of the molded product, etc., the preheating temperature control means It is preferable to perform feedback control in order to keep the temperature of S at a desired value.

As an example of the feedback control, as shown in FIG. 6, a temperature sensor 81 for measuring the temperature of the painting sheet S is provided near the preheater 4 of the sheet feeding device. On the other hand, a non-contact heating system using infrared radiation from the ceramic surface heated by a heating wire is used as the preheating heater 4. Then, the current (power) of the current (sinusoidal single-phase alternating current) supplied from the AC power supply 84 via the power supply line 83 is controlled through a control device 80 using a thyristor, and the heating wire (Nichrome) of the preheater 4 is controlled. (A known wire or the like). As a control method, for example, the temperature of the painting sheet S measured by the temperature sensor 81 is converted into an electric signal,
2 to the control device 80, while the control device 8
The target value of the pre-heating temperature of the painting sheet S set to 0 is compared with the current temperature of the painting sheet S. If there is a difference between the two temperatures, the control device 80 is controlled to converge the difference to 0. The phase of the trigger pulse of the thyristor is controlled, the energizing time during one cycle of the alternating current is controlled, and the output of the preheating heater 4, the surface temperature of the preheating heater 4, and the temperature of the painting sheet S are controlled.

The specific configuration and method of the control device 80 may be in accordance with known techniques. In addition, as the temperature sensor 81, a contact type sensor such as a thermistor, a thermocouple, or the like,
Any non-contact type sensor (infrared sensor) such as a photovoltaic cell and a photoconductive cell can be used. The temperature sensor 81
Is provided on the opposite side of the preheater 4 of the painted sheet S in FIG. 6, but may be provided on the preheater 4 side of the painted sheet S.

Even if the power supply to the preheater 4 is stopped, the temperature of the radiation surface of the preheater 4 does not drop suddenly.
Therefore, if it is desired to rapidly cut off the heat energy supplied to the painting sheet (abruptly stop the temperature rise of the painting sheet), as shown in FIGS. 1 and 7, the preheater 4 and the painting sheet S
A heat shielding plate 85 is inserted as a preheating temperature control means. 1 and 7, the heat shield plate 85 is provided on the base frame 6 by a driving mechanism (not shown) such as a stepping motor or a fluid pressure cylinder and is guided by a guide rail (not shown) running in the Y direction. During the heating of the painting sheet S, it stands by at a standby position indicated by a dotted line (outside the space between the preheating heater 4 and the painting sheet S), and when it is necessary to cut off the radiant heat from the preheating heater, as shown by a solid line. And the control device 8
0, it is inserted at a position between the preheater 4 and the sheet S with a picture. Then, the heat shield plate 85 returns to the standby position by the time of starting the next preheating.

The heat shield 85 has heat resistance and is a material that reflects heat rays (infrared rays), a material having low thermal conductivity, or a combination of both materials. For example, a layer in which a low heat conductivity layer made of glass fiber or asbestos is laminated on both front and back surfaces of an aluminum plate having high infrared reflectance and heat resistance is laminated.

When the heat shield plate 85 shields heat, the preheater 4 is naturally located at a position where a gap is large enough to allow the heat shield plate 85 to be inserted from the painted sheet S. But,
It is not always necessary for the preheater 4 to be in a state where the heat shield plate 85 is always kept in a non-contact state with the painting sheet S so as to allow a heat shield plate 85 to be inserted therebetween. That is, even if the preheating heater 4 is non-contact heating from the beginning, the preheating heater 4 retreats to a position farther away from the painted sheet only at the time of heat shielding by the heat shield plate, or at first only at the time of heat shielding by contact heating. It may be non-contact. However, non-contact heating is better than contact heating,
This is preferable in that molded article appearance defects due to heater contact marks do not occur.

The heat shield plate 85 may be used together with the preheating temperature control by the feedback control, or
Control of the preheating heater is performed by turning the heater on at a predetermined timing, and then turning the heater off after a predetermined time elapses.
The preheating temperature control may be used together with the off-control, or the preheating heater may be always on, and the preheating temperature control may be performed only by the heat shield plate 85. Further, the timing for moving the heat shield plate 85 to the heat shield position is determined after the painting sheet S is supplied to the preheat position.
Although the predetermined time may be elapsed, when the temperature of the painted sheet S is measured by the temperature sensor 81, the temperature of the painted sheet S may be increased to a predetermined temperature experimentally obtained as a condition value. These combinations may be appropriately combined depending on the required preheating temperature accuracy, the preheating temperature of the painted sheet, its material, the shape of the molded product, and the like.

In order to prevent the temperature of the preheated painted sheet S from rapidly falling due to the outside air while the painted sheet S is being conveyed from the preheater 4 to the female mold 12, FIG.
As shown in the figure, a hollow tubular heat retaining hood 86 may be provided along the endless annular chain 50 between the preheater 4 and the female die 12 so as to surround the same from the periphery. The heat retaining hood may be made of a metal plate such as iron or aluminum. Further, a known heat insulating material such as glass wool may be provided on the wall surface of the heat retaining hood 86. In addition, this heat retention hood 86
This equipment reduces the reduction of the preheating effect of the painted sheet.
In this sense, it can be said to be one component of the sheet preheating means.

On the other hand, as a sheet heating means, a molding die 1
The heating means of the heater 70 for heating the painted sheet S supplied to the sheets 2 and 25 may be any of various conventionally known heating means such as a ceramic heater and a planar heating element, similarly to the preheating heater. In addition, the heater 70 as the sheet heating means illustrated in FIG.
Has a heater whose heating surface is bendable and can be non-planar,
The structure is such that the non-contact heating of the painted sheet is possible at substantially equal distances on all heating surfaces. Further, in the apparatus configuration of FIG. 1, the preheating heater serving as the sheet preheating means and the heater 70 serving as the sheet heating means are provided as dedicated separate bodies. By forming them separately, the sheet preheating and the sheet heating can be performed separately at a more suitable time, at a more suitable temperature, or at a more suitable position.

After supplying to the molding dies 12, 25,
The heating temperature of the painted sheet S when the sheet is heated depends on the heat change.
Shape temperature (4.6 kgf / specified by JIS K7207)
cm ^Two(During bending stress). The heat distortion temperature is
The maximum necessary for heat softening for vacuum forming the painted sheet S
Low temperature. Heat the painted sheet above the heat distortion temperature
By softening, the painted sheet has a female cavity shape.
Plastic deformation can be performed along the length. However, heating temperature
When the painted sheet S melts due to too high a degree, the painted sheet is broken.
Heating temperature is the melting temperature.
(Or melting point).

The preforming means 90 transfers the painted sheet S heated by the sheet heating means to the cavity surface 1 of the female mold 12.
3a is provided with evacuation means (see FIG. 1).
The evacuation means comprises a vacuum source such as a vacuum pump or a vacuum tank. The vacuum source is connected to a vent 13b provided in the cavity surface 13a of the female mold 12 through an on-off valve that opens when evacuation is performed.

Hereinafter, the method and apparatus for simultaneous painting by injection molding of the present invention in the form illustrated in FIGS. 1 to 7 will be described in more detail.

First, the leading end of the continuous strip-shaped picture sheet S wound up from the roll R is held by the sheet cutter 56 by a sheet holding mechanism 55 such as a suction cup. Then, when there is a sheet gripping chuck 60 provided on the endless annular chain 50 at the feeding position, a sheet pulling mechanism 57 sliding on a guide rail (not shown) provided on the base frame 6 and running in the Y direction.
Holds the leading end of the continuous band-shaped painted sheet S held by the sheet holding mechanism 55, moves in the Y direction,
Pull out the picture sheet for one shot. At this time, each of the sheet gripping chucks 60 is in a gripping released state by the rollers 68 being pressed as shown in FIGS.
Next, the both ends in the width direction of the one-shot painting sheet S are
The sheet holding chuck 60 provided on the endless annular chain 50 holds the sheet. When the gripping is completed, the sheet pulling mechanism 57 may release the gripping of the painting sheet. In this state, the sheet cutter 56 cuts off one shot of the sheet S with one shot from the roll R side. Then, the endless annular chain 50 is appropriately fed in the Y direction according to the length of the painting sheet and the length of the preheater, and the painting sheet S is carried in from the feeding position to a predetermined preheating position facing the preheating heater 4. This is the sheet loading process. This state is shown in FIG.

The painting sheet S is heated in a non-contact manner by infrared radiation heating from the preheating heater 4 located above and away therefrom. The temperature of the preheating heater is controlled by, for example, a simple on / off control in which the heater is turned on after the painting sheet moves to the preheating position and turned off after a predetermined time has elapsed, thereby controlling the preheating temperature of the painting sheet. And further, the heat shield plate 85
But preheating temperature control. For example, when the preheating heater is turned off after a predetermined time has elapsed after the painting sheet S has been supplied to the preheating position, the heat shielding plate 85 moves from the standby position to the heat shielding position, Prevents excessive temperature rise. This is the sheet preheating step.

When the predetermined preheating step of the painted sheet is completed, the endless annular chain 50 is fed (in the direction of the rotation arrow attached to the sprocket wheel 41 in FIG. 1), and one shot is gripped by the sheet gripping chuck 60. Is transported to the supply position facing the female parting surface 14. After the conveyance, the sheet S with the picture is fixed and held on the parting surface 14 by the clamper 20. This completes the supply of the painting sheet S to the molding dies 12, 25. Thereafter, the endless annular chain 50 is fed in the reverse direction, and the sheet grip chuck 60 is returned to the feed-out position to prepare for the next shot of the painted sheet. This is the sheet supply process.

By the way, the molding dies 12, 2 used here
Reference numeral 5 denotes a non-planar parting surface, and the endless annular chain 5 is provided on the parting surface 14 side of the female mold 12.
0, a pair of left and right supply-side guides extending in the vertical direction (Z direction) while curving along the parting surface 14 to guide the passage through the large-diameter roller 62, the small-diameter roller 63, the sheet gripping chuck 60, and the like. A groove 36 is provided. The left and right endless annular chains 5 are also provided on the bottom side of the female mold 12.
A pair of right and left bottom-side guide grooves 38 extending in the vertical direction (Z direction) through which the large-diameter rollers 62 pass.

FIGS. 4 and 5 are cross-sectional views of the female side of the supply-side guide groove 36 in the XY plane. As shown in these drawings, the supply-side guide groove 36 is provided so that the endless annular chain 50 and the sheet holding chuck 60 are orthogonal to the sheet conveying direction.
It has a cross-sectional shape capable of regulating the position in the direction.
For this reason, the supply-side guide groove 36 has an intermediate wall 36A protruding in the groove width direction, and a lower portion (the fixed receiving piece portion 6) of the sheet gripping chuck 60 is located above (in the drawing) above the intermediate wall 36A.
5) has an opening groove 36a that opens in the parting surface 14 whose position is regulated. A large-diameter roller 62 and a small-diameter roller 63 provided on the endless annular chain 50 are inserted and guided so as to sandwich the intermediate wall 36A, and the large-diameter roller 62 is loosely fitted to the intermediate wall 36A and the bottom wall. Position restriction recesses 36d and 36c are provided. This position regulating recess 36
d, 36c and the intermediate wall 36A, the endless annular chain 5
0 and the sheet gripping chuck 60 are in two directions orthogonal to the sheet conveying direction, that is, the direction along the parting surface 14 curved in a convex shape (vertical direction and horizontal direction in FIG. 4).
The position is regulated with respect to.

Further, the sheet gripping chuck 60 is provided as shown in FIG.
As shown in FIG. 5, a fixed receiving piece 65 projecting laterally above the support member 61 to receive the back side (lower side) of the painted sheet S, and to be positioned above the parting surface 14. Movable presser piece 66 rotatably supported by support plate 64
And a sheet grip portion comprising: Movable presser piece 66
Is fixed by the compression coil spring 67.
Are urged in the direction for holding the painting sheet S in the clamping state. Therefore, the painted sheet S gripped by the sheet gripping chuck 60 can be moved substantially along the convexly curved parting surface 14 of the female mold 12.

Further, when the clamper 20 presses and fixes the picture sheet S to the female parting surface 14 on the endless annular chain 50 side of the movable presser piece 66, the interference preventing recess 21 provided on the female parting surface 14 is provided. A suppressed roller 68 is provided. When the roller 68 is suppressed by the concave portion 21 of the clamper 20, the movable pressing piece 66 separates from the fixed receiving piece 65 against the urging force of the compression coil spring 67, and the sheet gripping chuck 60 moves the The grip is released (see FIG. 5).

It should be noted that the endless annular chain 50 is provided with a necessary tension as necessary, so as to eliminate the slack.
In the embodiment shown in FIG. 1, a pair of tension applying sprocket wheels 46 that are in pressure contact with the endless annular chain 50 are provided below the female mold 12. By adjusting the position of the tension imparting sprocket wheel 46 with respect to the endless annular chain 50 (Y direction in FIG. 1), the endless annular chain 50 is adjusted.
Adjust the tension of. Further, the positions of the endless annular chain 50 and the sheet gripping chuck 60 with respect to the supply-side guide groove 36 of the female die 12 are uniquely determined. FIG.
As shown by the imaginary line, a sprocket wheel 47 for applying tension may be provided above the female die 12 (upstream side).

Next, the painting sheet S pressed and fixed to the parting surface 14 of the female mold 12 by the clamper 20 is heated and softened. In the embodiment illustrated here, since the parting surface 14 of the female mold 12 is a substantially convex curved surface, the heating heater 70 for heating and softening is rotated with respect to the holding case 75 as shown in FIG. It is composed of two heater plates, a first plate-like heating unit 71 and a second plate-like heating unit 72 movably held, and these two heater plates 71, 72 are bent and fixed with a picture sheet S. Radiant heating by non-contact heating at substantially equal distances can be performed on the heating surface. The heater 70 shown at the heating position in FIG.
Although not shown, a fluid pressure cylinder, a guide rail, and a driving mechanism are used to move the mold to a heating position between the molds shown in FIG. Reciprocating between these two positions so as to be positioned upward or laterally.

Then, the painted sheet S is heated to a temperature equal to or higher than the thermal deformation temperature to be heated and softened, and after the heated softening of the painted sheet is completed or after a certain time has elapsed after the start of the heating softening,
The air holes 1 provided in the female mold 12 are formed by a vacuum source (vacuum evacuation means) using a vacuum pump as the preforming means 90.
3b, the picture sheet S is vacuum formed and the female mold 1
2 so as to be along the cavity surface 13a of FIG.
Is preformed. In addition, vacuum forming also includes vacuum / pressure forming. This is the preforming step.

After pre-forming the painted sheet, the heater 7
0 moves / retreats between both dies to a retreat position outside the dies.
Thereafter, both the female mold 12 and the male mold 25 are clamped, and the cavity formed by the molds 12 and 25 is filled with a resin in a flowing state. Normally, a runner and a gate (not shown) communicating with the injection nozzle are provided on the male mold 25 side (not shown), and the resin in a flowing state is injected into the cavities formed by both molds through these. After the injection resin is solidified, the mold is opened to separate the female mold 12 and the male mold 25.

Then, a painted molded product in which the painted sheets S are laminated is obtained. In particular, when the painted sheet S is a laminate sheet, the surplus painted sheet S protruding from the peripheral portion of the painted molded product is cut (trimmed). Further, when the painting sheet S is a transfer sheet, only the base sheet is peeled off to leave the transfer layer on the molded product side.

The painted sheet S that can be used in the present invention is not particularly limited as long as it is a laminate sheet or a transfer sheet, and various conventionally known painted sheets can be used and are not particularly limited. In particular, the present invention is effective because a laminated type painting sheet is often thicker than a transfer sheet. In addition, among the laminated-type painted sheets S, a thick painted sheet is more preferable. In the present invention, even with such a painted sheet, a painted molded article can be manufactured with high productivity without extending the cycle time. When preheating and heating of the painted sheet S are performed in a non-contact manner, the painted sheet S having the adhesive layer can be supplied stably without the adhesive layer being thermally fused to the heater. Thus, it is possible to obtain a painted molded article having no appearance defect due to heat fusion.

The laminate type painting sheet S is a sheet having a configuration in which a base sheet has been subjected to decoration processing by printing of a decoration layer or the like representing a picture, a character, or the like. As the base sheet of the painted sheet S, a resin sheet having moldability is typically used. Examples of the resin sheet include polyamide resins such as nylon, polyester resins such as ethylene-isophthalate-terephthalate copolymer, and polybutylene terephthalate; olefin resins such as polypropylene, polyethylene, and olefin-based thermoplastic elastomers; polyvinyl fluoride; A single layer or a laminate of two or more sheets of a thermoplastic resin such as a fluororesin such as vinylidene chloride, a vinyl chloride resin, an acrylic resin, and an ABS resin (acrylonitrile-butadiene-styrene copolymer) is used. The thickness of the substrate sheet is usually about 30 to 700 μm for the laminate type, and 20 to 100 μm for the transfer type.
m.

The decorative layer may be a printed pattern such as a character or a pattern, a colored opaque or transparent (colored or uncolored) paint layer,
Alternatively, it is a functional layer such as a hard coating layer, an antifogging layer, and a conductive layer. It should be noted that these decorative layers are releasably carried on a base sheet, and after the injected resin and the painting sheet S are adhered to each other, the base sheet is peeled off and used to form a transfer sheet. In order to carry it releasably, known means such as providing a release layer on the base sheet may be used.

As the molding resin, those known in the art of simultaneous injection molding and painting can be used, and there is no particular limitation. For example, in the case of thermoplastic resins, olefin resins such as polypropylene, polyethylene, and olefin-based thermoplastic elastomers, vinyl chloride resins, acrylic resins, ABS (acrylonitrile-butadiene-styrene copolymer) resins, styrene resins, and AS (acrylonitrile- (Styrene copolymer) resin, polycarbonate resin and the like, and as the curable resin, unsaturated polyester resin, curable acrylic resin, two-pack curable urethane resin, epoxy resin and the like. The thermoplastic resin is melted by heating and injected in a fluidized state, and the curable resin is injected in a fluidized state as an uncured liquid material appropriately heated as needed.

[0072]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples.

[Embodiment] A painted molded product having a painted sheet laminated on its surface was manufactured by an injection molding simultaneous painting apparatus as shown in FIGS.

The painting sheet S to be used is an ink obtained by adding a color pigment such as a red stencil to an acrylic resin binder on one side of a transparent 125 μm-thick acrylic resin film of a methyl methacrylate-butyl methacrylate copolymer system. A decoration layer is formed by a combination of three wood grain patterns, and a 500-μm-thick brown heat deformation temperature (4.6 kgf / c according to JIS K7207) is formed from above the decoration layer.
An ABS resin sheet having a m ² bending stress of 103 ° C. is bonded by heat fusion, and further, the surface of the ABS resin sheet is
An adhesive layer made of a vinyl chloride-vinyl acetate copolymer is
It was formed to a thickness of μm to prepare a sheet with a picture. In addition, the ABS sheet side of the painted sheet is the back side, that is, the injection resin side.

In addition, as a molding die for forming a painted molded product, an injection molding die was prepared which can obtain a rectangular parallelepiped molded product having a length of 300 mm, a width of 200 mm, and a depth of 40 mm. The female mold 12 of this mold has a ventilation hole 13b for sucking air in the mold for sheet preforming, and has guide grooves 36 and 38 through which the endless annular chain 50 of the sheet feeding device 5 passes.
The parting surface 14 is not a curved surface but a flat surface. Heat-resistant ABS resin was used as the molding resin. The temperature of the injection resin was 240 ° C., and the mold temperature was 60 ° C.

In the forming process, first, the leading end portion of the continuous belt-shaped picture sheet S unwound from the roll R and held by the sheet holding mechanism 55 is gripped by the sheet pulling mechanism 57, and both ends in the sheet width direction are held. The sheet S with the picture was fed by a length of one shot through the both ends of the sheet holding chuck 60 in a released state. Then, the sheet holding chuck 60 is moved to the sheet S with the picture.
After the sheet is pulled out, the sheet pulling mechanism 57 releases the holding of the picture sheet S, and the downstream side of the picture sheet S fed out in this state is cut by the sheet cutter 56, and one sheet of the picture sheet S for one shot is cut. Was brought in. A preheater 4 composed of a ceramic panel heater is provided above the picture sheet S at the carry-in position (preheat position) so that the distance from the picture sheet S is 5 mm.
The pre-heater was set at a surface temperature of 150 ° C., and the painted sheet was radiatively heated in a non-contact manner for 20 seconds. The temperature of the painted sheet was 80 ° C. at the time of heating for 20 seconds. Then, after 20 seconds from the start of the radiant heating, the heat shield plate 85 is inserted from the standby position into the heat shield position between the preheater 4 and the painting sheet S immediately below the preheater 4, thereby shielding the radiant heat and further increasing the temperature. The rise was suppressed. Since the preheating step of the painted sheet S is performed during the pre-forming of the painted sheet S in the previous cycle and the injection molding using the same, the cycle time does not increase.

Then, the endless annular chain 50 is sent,
The painted sheet S which was grasped and preheated was conveyed onto the parting surface 14 of the female die 12 and pressed and fixed to the parting surface 14 by the clamper 20 to complete the supply of the painted sheet S to the forming die. It takes 10 seconds to supply the painted sheet S, during which time the temperature of the painted sheet S is raised from 80 ° C. to 65 ° C.
° C. Thereafter, a plate-shaped heater 70 made of a ceramic panel heater, which is a heater different from the preheater 4, is moved from the retreat position outside the forming dies 12, 25 to form the dies 12, 25. The surface temperature is set to 350 ° C., and the sheet S with the picture and the heater 70
The painting sheet S was softened by non-contact radiant heating at a distance of 40 mm (specifically, the plate-shaped heating units 71 and 72). 10 seconds after the start of heating, the temperature of the painted sheet is 140 ° C
The temperature was suitable for vacuum forming. Then, vacuum forming was performed using the female mold as a vacuum mold, and the painted sheet S was placed along the cavity surface 13a of the female mold, thereby completing the preliminary molding. Thereafter, the heater 70 is retracted to the outside of the molding dies 12, 25, the male and female dies 12, 25 are clamped, and the injection resin heated and melted into a cavity formed by the male and female dies 12, 25 is injected. Then, after the resin was cooled and solidified, the mold was opened to obtain a painted molded product on which the painted sheet S was laminated.

COMPARATIVE EXAMPLE In the example, a painted product was obtained without preheating the painted sheet. Without preheating, it took 20 seconds to heat the painted sheet to 140 ° C. with a heater. The heating time required was 10 seconds longer than in the example, and the cycle time increased accordingly.

[0079]

According to the method and apparatus for simultaneous painting by injection molding of the present invention, the painted sheet is preheated before being supplied to the molding die. The time for heating to the vacuum forming temperature can be reduced. Therefore, the time of the mold opening state can be shortened, and the productivity can be improved by shortening the cycle time. Moreover, since the temperature of the prepainted sheet is controlled by the preheating temperature control means, a stable preheating temperature can be realized without being preheated to an excessive temperature. As a result, deformation and distortion of the painted sheet during supply to the molding die are suppressed, and the painted sheet can be supplied to the molding die in a stable manner in terms of shape and temperature. As a result, in addition to shortening the cycle time, a stable simultaneous injection molding painting method can be performed, and a high quality painted molded product can be obtained.

If a heat shield plate interposed between the preheater and the painted sheet is used as the preheat temperature control means, the preheat temperature can be suppressed from rising more than necessary, and a stable preheat temperature can be realized. . As a result, the painted sheet can be more stably supplied to the mold in shape and temperature.

In the sheet supply step, when the pre-heated painted sheet is supplied to the forming die, if the pre-heated painted sheet is supplied to the forming die, the pre-heated painted sheet is supplied to the forming die. In addition, it is possible to prevent the temperature from lowering due to contact with the outside air, and to more stably supply the painted sheet to the mold.

[Brief description of the drawings]

FIG. 1 is a side view showing the overall configuration of an injection molding simultaneous painting apparatus according to the present invention.

FIG. 2 is a perspective view showing the vicinity of a preheater and a sheet feeding device in FIG. 1;

FIG. 3 is a partially enlarged side view showing an endless annular chain and a sheet gripping chuck in the sheet feeding device of FIG. 1;

FIG. 4 is a partially enlarged cross-sectional view illustrating a guide groove provided in the endless annular chain, the sheet gripping chuck, and the female die of FIG. 3;

FIG. 5 is a partially enlarged cross-sectional view for explaining the operation of the endless annular chain and the sheet gripping chuck of FIG. 3;

FIG. 6 is a side view conceptually illustrating a control device using a temperature sensor as one mode of preheating temperature control means of a preheating heater.

FIG. 7 is a side view illustrating a heat shield plate as preheating temperature control means and a heat retaining hood.

[Explanation of symbols]

 Reference Signs List 1 support frame 3 rail 4 preheater (sheet preheating means) 5 sheet supply device (sheet supply means) 6 base frame 7 connecting member 8 connecting plate 9 ram 11 movable plate 12 female die 13 cavity 13a cavity surface 13b vent hole 14 parting Surface 20 Clamper 21 Concave portion 24 Connecting rod 25 Male type 31 Fixed plate 32 Injection nozzle 33 Core portion 34 Male type parting surface 36 Supply side guide groove 36A Intermediate wall 36a Opening groove 36c, 36d Position control concave portion 38 Bottom side guide groove 41 45 Sprocket wheel 46, 47 Sprocket wheel for applying tension 50 Endless annular chain 55 Sheet holding mechanism 56 Sheet cutter 57 Sheet pull-out mechanism 60 Sheet gripping chuck 61 Support member 62 Large diameter roller 63 Small diameter roller 64 Support plate 6 Reference Signs List 5 Fixed receiving piece part 66 Movable holding piece part 67 Coil spring 68 Roller 70 Heater (sheet heating means) 71 First plate-shaped heating part 72 Second plate-shaped heating part 75 Holding case 80 Preheater control device 81 Temperature sensor 83 Power supply line 84 AC power supply 85 Heat shield plate (preheating temperature control means) 86 Heat retaining hood 90 Vacuum source (preforming means) R Roll S Pictured sheet

Claims (6)

[Claims] 1. A sheet supply step of supplying a painting sheet to a pair of molding dies in an opened state, wherein the painting sheet is heated to a temperature equal to or higher than a thermal deformation temperature of the sheet by a sheet heating means, and a vacuum from one molding mold is applied. The pre-forming step of drawing the painted sheet along the cavity surface of the mold by pulling, the bonding step of clamping the mold, injecting the resin in a fluid state into the cavity, and bonding the painted sheet and the resin, In the simultaneous injection molding painting method which is performed at least in order, before the sheet supplying step of supplying the painting sheet to the molding die,
A simultaneous painting method for injection molding, wherein a preheater of a sheet preheating means preheats a painted sheet to a temperature lower than a thermal deformation temperature of the sheet, and performs a preheating step of controlling the preheating temperature of the painted sheet by a preheating temperature control means. 2. A heat shield plate is used as preheating temperature control means,
2. The injection according to claim 1, wherein the heat shield plate is interposed between the preheater located at a position not in contact with the painting sheet and the painting sheet to suppress a temperature rise of the painting sheet to perform the preheating step. Simultaneous painting method. 3. The simultaneous painting method for injection molding according to claim 1, wherein in the sheet supplying step, when the preheated painted sheet is supplied to the molding die, the painted sheet is supplied while being covered with a heat retaining hood. 4. A preheating means comprising at least a preheating heater and a preheating temperature control means for preheating a painted sheet before being supplied to a pair of forming dies to a temperature lower than a heat deformation temperature of the sheet. Sheet supply means for supplying the post-painted sheet from the preheating position to the forming die, sheet heating means for heating the preheated painted sheet supplied to the forming die to a temperature equal to or higher than the thermal deformation temperature of the sheet, And a pre-molding means comprising vacuum evacuation means for bringing the painting sheet along the cavity surface. 5. A preheating temperature control means comprising at least a heat shield plate, wherein the heat shield plate is located at a position distant from the prepainted sheet and between the preheater and the prepainted sheet. 5. The simultaneous injection molding and painting apparatus according to claim 4, wherein the apparatus moves between a standby position and a standby position. 6. The simultaneous injection molding and painting apparatus according to claim 4, further comprising a heat retaining hood for covering the painting sheet supplied to the molding die from the sheet supply means, between the preheater and the molding die.