JP2004322501A - Molding method of decorating molded article and equipment therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen elongation of a decorating sheet and distortion of a pattern and also to prevent break even when a decorating molded article having the decorating sheet stacked integrally on the surface has such a shape as being bent sharply in the two-dimensional direction. <P>SOLUTION: In a molding method of the decorating molded article by an insert molding method, the decorating sheet is vacuum-formed beforehand by a vacuum forming mold and then unnecessary portions thereof are trimmed. The formed sheet thus obtained is inserted into an injection mold and a resin is injected thereinto. Herein a vacuum forming process is made to comprise (A) a fixing process wherein the decorating sheet 10 is fixed to a frame 1, (B) a heating process wherein the sheet is heated by a heater 2, (C) a deforming process wherein the heated decorating sheet is bent together with the frame and deformed in the two-dimensional direction and (D) a forming process wherein the deformed decorating sheet is vacuum-formed by the vacuum forming mold 3. The frame is provided with a deforming mechanism using a hinge or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding technique for a decorative molded product in which a decorative sheet is laminated on the surface of a molded product. The present invention relates to a molding technique that can reduce the elongation of a sheet and reduce the distortion of a pattern even for a molded product that is bent in a large two-dimensional direction such as found in automobile interior parts such as a center console.
[0002]
[Prior art]
A decorative molded product decorated by laminating a decorative sheet on the surface of the molded product is used in various applications such as vehicle interior parts. As one method for molding such a decorative molded product, an injection molding simultaneous decoration method is known. In the simultaneous injection molding decoration method, after the decorative sheet is inserted into the injection mold, the three-dimensional shape along the surface of the molded product is usually obtained by vacuum forming the decorative sheet in advance using the injection mold as a vacuum mold. After that, by clamping the mold and injecting the resin, a decorative molded product in which a decorative sheet is laminated and integrated on the surface of the three-dimensional molded product can be obtained.
[0003]
However, if the shape of the molded product is a shape that is largely bent as a whole, such as a car center console (see FIG. 6), for example, only the cross-sectional shape of the molded product in the direction perpendicular to the bending direction can be seen. For example, even if the sheet stretching amount is small (the drawing is shallow) and the shape is easy to form, the entire molded product has a large sheet stretching amount (the drawing is deep). As a result, the pattern of the decorative sheet may be greatly distorted or the sheet may be broken without being stretched. Therefore, in order to avoid these problems, when the decorative sheet is supplied to the injection mold to reduce the amount of sheet stretching in the bending direction, the shape of the molded product is supported. Using a bent frame (sheet clamp), the decorative sheet is sent to this frame, and the decorative sheet is bent in advance, and then heated with a heater for vacuum forming. Yes (see Patent Document 1, Patent Document 2, Patent Document 3, etc.).
[0004]
[Patent Document 1]
Japanese Patent No. 2694917 [Patent Document 2]
Japanese Patent No. 2694920 [Patent Document 3]
Japanese Patent No. 2749540 [0005]
[Problems to be solved by the invention]
However, according to the techniques of the above-mentioned patent documents, it is possible to cope with pattern distortion or the like caused by large elongation, but the shape of the molded product is easily limited due to the combined use of the injection mold and the vacuum mold. In addition, a special mold structure compared to a normal injection mold, such as providing a suction hole to make the injection mold a vacuum mold, increases the cost of the mold and increases the equipment cost. There was also a problem.
[0006]
For these points, do not use the vacuum mold as an injection mold, and use a vacuum molding machine separate from the injection molding machine to vacuum-decorate the decorative sheet before inserting it into the injection mold. If the insert molding method of molding is adopted, the point of high cost can be solved. Further, even a molded product having a large stretch amount can be prevented from tearing if a thick sheet is used as the decorative sheet so as to cope with a deep drawing in a two-dimensional direction. However, even if the sheet can be prevented from being torn, the pattern also grows at the same time. Therefore, it is impossible to prevent the pattern from becoming too large, which may cause a design problem. In addition, there is a problem that the cost increases as the sheet becomes thicker.
[0007]
That is, the problem of the present invention is that the decorative molded product in which the decorative sheet is laminated and integrated with the injection molded product, even if the molded product has a shape that is greatly bent in the two-dimensional direction, the elongation of the sheet is reduced and pattern distortion is reduced. To make it smaller.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the molding method of the decorative molded product of the present invention includes a vacuum molding step in which a decorative sheet is molded into a three-dimensional shape in advance by a vacuum molding die, and then trims excess portions to form a molded sheet. Then, the molded sheet is inserted into an injection mold, the injection mold is closed, and a resin in a fluid state is injected into the mold to integrate the resin and the molded sheet. The vacuum forming step includes (A) a fixing step of fixing the periphery of the molded portion of the decorative sheet to the frame, (B) a heating step of heating the fixed decorative sheet by a heating means, and (C). It was set as the structure which consists of the deformation | transformation process which deform | transforms the heated decorating sheet | seat in the two-dimensional direction with the frame, and the shaping | molding process which vacuum-forms the deformed decorating sheet using a vacuum forming die.
[0009]
By adopting a molding method having such a configuration, after the decorative sheet is heated, for example, it is bent in advance into a rough overall shape of the decorative molded product, for example, by folding it into a “<” shape. After deformation, vacuum forming is performed with a vacuum forming die, so that even when the shape is greatly bent in the two-dimensional direction, the elongation at the time of vacuum forming the sheet can be reduced to reduce the pattern distortion. In addition, since the substantial drawing at the time of vacuum forming becomes shallow, even a relatively thin decorative sheet can be handled. Further, since the pre-deformation causes the decorative sheet to be deformed by the frame after heating, the vacuum forming apparatus can be used only by making it possible to deform the frame used there, such as by bending, and a general apparatus can be used. Also, the increase in costs such as equipment costs can be reduced.
[0010]
Further, the decorative molded product molding apparatus of the present invention is a molding device that performs the above-described decorative molded product molding method, and the vacuum molding apparatus that takes charge of the vacuum molding process is arranged around the molded portion of the decorative sheet. It was set as the structure which has a frame to fix and has a deformation | transformation means which deform | transforms the decoration sheet | seat with which this frame was fixed to the two-dimensional direction with the frame.
[0011]
By setting it as the shaping | molding apparatus of such a structure, the said shaping | molding method can be implemented and the said effect can be enjoyed. That is, even in a shape that is greatly bent in the two-dimensional direction, the pattern distortion can be reduced by reducing the elongation of the sheet. Further, as a vacuum forming apparatus, a general apparatus can be used, and an increase in costs such as equipment costs can be reduced.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0013]
Vacuum forming process :
In the vacuum forming process, a pack that reproduces the injection mold cavity shape of the part that requires decoration of the molded product is produced by vacuum forming of the decorative sheet, and then the unnecessary part is trimmed to form the molded sheet. Make it.
[0014]
Conventional general vacuum forming processes include (A) a sheet fixing process for fixing a (decoration) sheet to a frame, (B) a heating process for heating the sheet using a heating means such as a heater, and (D) vacuum. It consists of three steps of forming the sheet along the surface of the mold using the mold.
[0015]
On the other hand, in this invention, the deformation | transformation process (C) which deform | transforms a decorating sheet in advance is provided between the heating process of said (B), and the shaping | molding process of (D). This deformation process is a process of deforming the decorative sheet in the two-dimensional direction together with the frame. In the deformation process, the decorative sheet is deformed not by the air pressure difference between the front and back of the decorative sheet but by the deformation of the frame.
[0016]
Here, FIG. 1 is explanatory drawing which illustrates each process of the vacuum forming process including this deformation | transformation process notionally. FIG. 1A shows a fixing step, and the decorative sheet 10 fixes the periphery of a molding portion to be stretched during vacuum molding with a frame 1. Next, FIG. 1 (B) is a heating process, and the decorative sheet 10 fixed by the frame 1 is heated by non-contact heating by the heating means 2 such as a heater from the front and back in FIG. Next, FIG. 1C shows a deformation step, in which the decorated decorative sheet 10 is deformed in the two-dimensional direction by bending the frame 1 together. Next, FIG. 1D is a forming step, in which the decorative sheet 10 fixed to the frame 1 and deformed is vacuum formed by the vacuum forming die 3.
[0017]
In order to perform the deformation process, the frame 1 may be provided with deformation means so that the fixed decorative sheet 10 can be deformed in the two-dimensional direction together with the frame 1. The deformation means is not particularly limited as long as it can deform the fixed decorative sheet in a two-dimensional direction, and a conventionally known mechanism such as a hinge mechanism may be appropriately employed.
[0018]
Here, FIG. 2A is a plan view illustrating the planar shape of the frame 1, and the frame 1 includes a frame main body 1a and a presser 1b as illustrated in a side view of FIG. 2B, for example. The decorative sheet 10 is pressed and fixed to the frame body 1a by the presser 1b. The frame 1 illustrated in FIG. 2 employs a hinge as the deformation means 4. The deformation means 4 is provided on two opposite sides of a rectangular frame. Then, as shown in the side view of FIG. 2C, the decorative sheet 10 fixed by the frame 1 is folded in the two-dimensional direction together with the frame 1 by bending the frame 1 at the part of the deformation means 4 formed of a hinge. Deform. The hinge provided as the deforming means 4 has a rotational axis at a position in the frame thickness direction, which is just a portion overlapping the decorative sheet, so that the decorative sheet is forcibly extended or pushed in during deformation. There is nothing. As shown in FIGS. 2B and 2C, the frame body 1a of the frame has a structure in which the hinge is divided into left and right so that the frame can be bent with the hinge. Further, the presser 1b is also escaped so that the hinge part does not interfere when bent.
[0019]
Note that “deformation in the two-dimensional direction” means that, as illustrated in FIG. 3, the decorative sheet 10 that was initially a flat surface parallel to the XY plane is deformed flat in a cross section in the XZ plane after the deformation. Although it is not done, it is to change into a deformed shape with irregularities such as bending in the cross section on the YZ plane.
[0020]
In this way, by transforming the decorative sheet 10 together with the frame 1, even if there is no or no stretching of the decorative sheet, there is almost no state, that is, substantially without forming (stretching) the decorative sheet. The shape can be changed from a two-dimensional planar shape to a planar shape in which it is bent or bent.
[0021]
When the frame 1 is deformed by a deforming means such as a hinge mechanism using a hinge, the frame 1 may be deformed manually, or may be deformed by driving the frame 1 with a driving source such as an air cylinder. 4A and 4B conceptually show an example of the deformation operation of the frame 1 by the air cylinder 5. FIG. The frame 1 is slidably mounted on the guide member 6 at the left and right portions of the deformation means 4, and an air cylinder 5 is connected to each of the left and right ends of the frame 1. Then, as shown in FIG. 4B, by extending the air cylinder, the frame 1 is bent at the portion of the deforming means 4 by its own weight and decorated to a shape that approximates the molding shape of the vacuum molding die 3. The sheet can be deformed.
[0022]
In the description so far, the decoration sheet is deformed by the frame in one place, but the decoration sheet is transformed into a more complicated shape such as a zigzag shape or a U-shape as two or more places. It can also be made. Further, when the hinge is used as the deformation means, the frame is deformed so as to be bent at the rotation axis of the hinge, but other deformation means (for example, a leaf spring) may be employed to deform the frame. Alternatively, a plurality of hinges may be used to bend little by little, and a smooth curved shape may be approximated by a broken line.
However, the decoration sheet in the deformation process does not need to be deformed to exactly the same shape as the final product, and approximates the shape of the molded product in the direction of increasing the drawing during vacuum forming. If the shape is adopted, the effect of the present invention can be sufficiently obtained.
[0023]
By the way, the deformation process is performed after the heating process in which the decorative sheet is heated with the frame fixed, but conversely, if the deformation process is performed before the heating process, the heating of the decorative sheet is surface. Since it becomes non-uniform, it is not preferable. If the heating of the decorative sheet becomes non-uniform, the stretch amount of the decorative sheet at the time of vacuum forming becomes more uneven (more than the surface distribution of the stretch amount according to the molding shape), and depending on the type of the sheet Breaks.
Further, if the heating step is performed before the deformation step, known heating means such as a heater can be arranged on the upper side, the lower side, or both sides of the frame, and heating can be performed in the same manner as in the past. However, if the heating process is performed after the deformation process and uniform heating is performed after the deformation process, the heating means such as a heater is also shaped or arranged in accordance with the shape of the deformed decorative sheet, It is necessary to make the distance between the decorative sheets constant. However, in this case, it is necessary to change the heater shape and arrangement for each shape of the decorative sheet after deformation, that is, the shape of the decorative molded product, which is not practical.
[0024]
Note that the heating means that interferes with the deformation of the frame may be retracted to a position where it does not interfere, for example, by shifting it to the side. Or conversely, the frame may be separated by moving it from the heating means onto the vacuum forming die.
[0025]
As described above, the vacuum forming process in the present invention has been described mainly with respect to the deformation process (and the heating process), but other processes in the vacuum forming process may be the same as those of the conventionally known vacuum forming process. The description which becomes is abbreviate | omitted.
The decorative sheet after vacuum forming in such a vacuum forming process trims unnecessary portions around and inside to form a molded sheet for insert.
[0026]
Decorative sheet :
Here, the decorative sheet that can be used in the present invention will be described. As the decorative sheet, a conventionally known sheet may be used depending on the application, and such a decorative sheet is usually composed of a base sheet and a decorative layer or the like appropriately provided for further enhancing the design. .
[0027]
The substrate sheet is selected in consideration of suitability for vacuum forming, and a resin sheet made of a thermoplastic resin is typically used. As the thermoplastic resin, acrylic resin, polyolefin resin such as polypropylene and polyethylene, polycarbonate resin, ABS resin, vinyl chloride resin, etc. are generally used. The base sheet is used as a single-layer sheet of these resins or a multilayer sheet of the same or different resins.
Although the thickness of a base material sheet is selected according to a use, it is about 0.1-1.0 mm normally, However, Considering cost etc., about 0.3-0.7 mm is common. In general, as a decorative sheet, as illustrated in the cross-sectional view of FIG. 5, a sheet having a two-layer structure in which the base sheet is made up of layers separated and independent (base sheets 11 a and 11 b) is often used. It is done. In this case, the front side (upper side of the drawing) base sheet 11a is often used as an acrylic resin as a transparent layer, while the back side base sheet 11b is concealed and has good adhesion to the injection resin. Corresponding to the resin, a colored (concealing) sheet such as ABS resin or polypropylene resin is used.
[0028]
The decorative layer is typically a pattern layer on which a pattern or the like is printed. For printing, conventionally known appropriate methods such as gravure printing, offset printing, letterpress printing, screen printing, and ink jet printing are adopted.
In addition, as the decoration layer, a metal thin film layer or the like in which a metal such as aluminum is partially or entirely formed by a vapor deposition method or the like is also used as appropriate. The decorative layer may be a well-known functional layer such as a hard coating film, a conductor layer, a magnetic layer, an antibacterial agent layer, and a phosphor layer, in addition to simple design.
The pattern of the pattern layer is, for example, a wood grain pattern, a stone pattern, a grain pattern, a tiled pattern, a brick pattern, a fabric pattern, a leather pattern, letters, symbols, figures, geometric patterns, full-color solids, etc. is there.
A known ink may be used for the ink of the pattern layer or the like according to the application. Binder resin is acrylic resin, urethane resin, cellulosic resin, etc., and colorant is titanium white, carbon black, petal, cobalt blue and other inorganic pigments, phthalocyanine blue, isoindolinone, quinacridone, etc. Organic pigments, metal pigments such as aluminum powder, pearlescent pigments such as titanium dioxide-coated mica powder, or dyes are used.
[0029]
Moreover, in order to improve the adhesiveness with the injection resin, the back surface of the decorative sheet,
An adhesive layer is provided. For the adhesive layer, a thermoplastic resin, a curable resin, or a rubber-based resin, specifically, a urethane resin, a polyester resin, a polyamide resin, or the like is used according to the injection resin.
[0030]
Insert molding process :
In the insert molding process, the molded sheet obtained by trimming unnecessary parts after the vacuum forming process is inserted into an injection mold, then clamped, and the resin is injected into the mold to mold with the resin. A decorative molded product in which the sheet is laminated and integrated is formed. This insert molding step may be the same as conventionally known insert molding.
[0031]
Insert molding that is mounted on an injection mold as a molded sheet that is molded in the shape of a decorative molded product in advance is a form that combines an injection mold and a vacuum mold in the so-called injection molding simultaneous decoration method. In contrast, it has the following advantages. In this form of injection molding simultaneous decorating method, since the injection mold is also used as a vacuum mold, the number of work steps is reduced, which is good in terms of productivity. In order to keep it along, decorative sheets will be stacked even in places where decoration is not necessary, and patterns will be attached, and conversely, shapeability that does not require decoration will also be affected by moldability In addition, the shape is likely to be limited. However, if the insert molding method is used, there is an advantage that it is difficult to limit such a shape.
[0032]
In addition, resin according to a use is used for injection resin, and thermoplastic resins, such as polyolefin resin, such as polyethylene and a polypropylene, ABS resin, a styrene resin, a polycarbonate resin, an acrylic resin, and a vinyl chloride resin, are typical. Alternatively, a thermosetting resin such as a urethane resin or an epoxy resin may be used.
[0033]
Other :
As described above, the present invention has a main feature in that the decorative sheet is deformed together with the frame in advance by deforming the frame before vacuum forming after heating the sheet. The method for fixing the decorative sheet to the frame is not limited to the above description without departing from the spirit of the present invention. Further, the vacuum forming in the present invention includes vacuum / pressure forming using pressure and pressure together.
Further, the use of the decorative molded product is not limited to vehicle interior parts.
[0034]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[0035]
[Example 1]
As the decorative molded product 20, an automobile center console having a substantially L shape as shown in the perspective view of FIG. 6, a height of 20 cm, a length of 30 cm, and a width of 25 cm and having two openings is as follows: It produced in the same way.
[0036]
The used decorative sheet 10 has a layer structure as shown in the cross-sectional view of FIG. 5. First, a woodgrain pattern layer is decorated by gravure printing on the back surface of a 75 μm transparent acrylic resin sheet serving as a base material sheet 11a on the front side. Formed as layer 12. Next, a urethane resin adhesive layer (not shown) is applied to the decorative layer surface, and laminated with a 400 μm-thick concealed colored ABS resin sheet as the back side base material sheet 11b to produce a desired decorative sheet 10 did.
[0037]
On the other hand, the frame 1 has a width of 40 cm and a length of 55 cm, and has a shape as shown in FIGS. 4A and 4B, and a pair of deformation means 4 at 30 cm from the end in the length direction. Hinges are installed, and air cylinders 5 are installed at both ends in the longitudinal direction of the frame, and after the heater is retracted, the fixed decorative sheet is bent into a shape that is bent at an angle of 100 degrees. I was able to do it.
[0038]
And after fixing the said decoration sheet to the said frame, a decoration sheet is heated for 40 second with the heater panel set to 400 degreeC from the distance of 15 cm each on the upper side and lower side of a decoration sheet, and sheet | seat temperature is set. Heated to about 170 ° C. Then, the heater panel is retracted in the horizontal direction, and immediately after that, the frame is deformed. At the same time, the vacuum forming die installed on the lower side of the frame is raised, and after the decorative sheet and the vacuum forming die are in contact, vacuum forming is performed. The mold was evacuated and the decorative sheet was vacuum formed into a mold shape. The decorative sheet after vacuum forming was good without extreme pattern distortion.
[0039]
Next, the decorative sheet after vacuum forming was trimmed to remove an extra portion around the forming portion and two opening portions inside the forming portion to obtain a forming sheet.
Next, after inserting this molded sheet into an injection mold, the mold is clamped, an ABS resin is injected into the mold, and a decorative sheet (molded sheet) is laminated and integrated on the surface of the molded article. Was molded.
[0040]
[Comparative Example 1]
In Example 1, a decorative sheet was vacuum-formed in the same manner as in Example 1 except that a normal frame having no deformation means was used. As a result, the decorative sheet was stretched almost 5 times on the bottom side (corresponding to the bent part of the molded product), and the pattern looked completely different from the other parts where the pattern did not stretch much. Moreover, the thickness of the decorative sheet was about 90 μm at the thin part, and if the handling was bad, wrinkles etc. entered immediately and could not be used.
[0041]
【The invention's effect】
According to the present invention, even if the shape of the molded product is greatly bent in the two-dimensional direction, the pattern distortion can be reduced by reducing the elongation of the decorative sheet during vacuum forming. In addition, since the substantial drawing at the time of vacuum forming can be made shallower, even a relatively thin decorative sheet can be handled. Further, the vacuum forming apparatus only needs to be able to be deformed, for example, by bending its frame, so that a general apparatus can be used, and an increase in costs such as equipment costs can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram conceptually illustrating a vacuum forming process in the present invention.
FIG. 2 is a cross-sectional view conceptually showing an example of a frame deformation means.
FIG. 3 is a perspective view illustrating the meaning of two-dimensional deformation.
FIG. 4 is a diagram conceptually showing an example of a frame deformation operation.
FIG. 5 is a cross-sectional view showing an example of a decorative sheet used in the present invention.
FIG. 6 is a perspective view illustrating an outline of an example of a three-dimensional shape of a decorative molded product applicable in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Frame 1a Frame main body 1b Presser 2 Heating means 3 Vacuum forming die 4 Deformation means (hinge)
5 Air Cylinder 6 Guide Member 10 Decorating Sheet 11a Base Material Sheet 11b Base Material Sheet 12 Decoration Layer 20 Decorated Molded Product

Claims (2)

After passing through a vacuum forming step in which the decorative sheet is formed in a three-dimensional shape in advance by a vacuum forming mold, trimming the excess part to form a molded sheet, then inserting the molded sheet into the injection mold and closing the injection mold, In the molding method of the decorative molded product by the insert molding method in which the resin in a fluid state is injected into the mold and the resin and the molded sheet are integrated,
The vacuum forming step was (A) a fixing step of fixing the periphery of the molded portion of the decorative sheet to the frame, (B) a heating step of heating the fixed decorative sheet by a heating means, and (C) heating. A method for forming a decorative molded product, comprising: a deformation step of deforming the decorative sheet together with the frame in a two-dimensional direction; and (D) a forming step of vacuum-forming the deformed decorative sheet using a vacuum forming die. A molding apparatus for carrying out the molding method for a decorative molded product according to claim 1, wherein the vacuum molding apparatus responsible for the vacuum molding step includes a frame for fixing the periphery of the molded portion of the decorative sheet, and the frame is fixed. A device for forming a decorative molded product, comprising a deformation means for deforming the decorative sheet together with the frame in a two-dimensional direction.

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