JPH0340720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for transferring an arbitrary pattern onto the surface of a previously molded resin product.

(Prior art) Methods for forming arbitrary patterns on the surface of resin molded products include a method of directly forming a pattern on the surface of the resin molded product by printing or painting, and a hot stamping method. It has the disadvantage that it is difficult to apply the pattern, and the formed pattern is easily worn out and disappears. Therefore, Japanese Patent Publication No. 51-33456 discloses a method for painting resin molded products, which allows patterning to be easily applied even to curved surfaces and prevents the pattern from disappearing, which involves transferring the pattern and molding the resin at the same time. Ta.

This involves heat-forming a transfer sheet with an arbitrary pattern formed on a heat-moldable base sheet with the patterned surface as the inner surface to form a painted molded product that matches the inner surface of a molding mold. The painted molded product is mounted on the inner surface of a molding mold, and then a molding resin is supplied to the inner surface of the decorated molded product and molded, and then the molded molded product is removed and the base of the transfer sheet is placed on the molded product. This method involves peeling and removing the sheet.

In addition, a method of transferring a transfer film (sheet) to a resin molded product with a curved surface was developed in 1983.
This is disclosed in Japanese Patent No. 33835, in which a transfer film is first heated and softened using a vacuum forming means and then suctioned to a certain extent, and then further heated and softened using a pressure forming means while being pressed. The transfer film is completely attached to the surface of the molded product, and then the transfer film is transferred to the surface of the molded product by applying heat and pressure in the latter step.

(Problem to be Solved by the Invention) However, in the former conventional example, in order to implement the method, the transfer sheet must be molded in advance so as to match the inner surface of the mold receiving mold.
Furthermore, since the molding process and the transfer process are performed at the same time, the painted molded product must be mounted on the molding mold prior to molding, which delays the resin molding cycle time and reduces productivity. Ta.

In addition, in the latter conventional example, in order to attach and transfer the transfer film to the molded product, a press plate corresponding to the surface shape of the molded product is required as a press molding means, and the device is complicated. When the transfer film was attached to the outer peripheral side of the product, the adhesion (transfer) of the transfer film to the outer peripheral side of the molded product was insufficient.

In addition, in this conventional example, when attaching and transferring a transfer film to the outer surface of a molded product, the transfer film is preheated, but the molded product is not heated in any way.
There is a large temperature difference between the film and the molded product, and therefore, when the transfer film is suctioned by a vacuum forming means to a certain extent, minute wrinkles and air bubbles occur in the gap between the film and the molded product due to the temperature difference. However, even if this is heated and softened and pressed using a press molding means in a post-process, the wrinkles and air bubbles that have occurred cannot be removed, and beautiful transfer cannot be achieved.

In view of these problems, the present invention eliminates the need to mold the transfer sheet in advance, does not cause a delay in the molding cycle time, can perform molding and transfer in separate processes, and requires special pressing when attaching the transfer film. It is an object of the present invention to provide a novel pattern transfer method that does not require a molding means and can particularly ensure transfer to the outer peripheral side surface of a molded product.

(Means to solve the problem) In order to achieve the above purpose, the following measures will be taken. That is, a preheated resin molded product having an upper surface and an outer circumferential side is placed so that its circumferential edge is positioned on a suction table, and an arbitrary pattern is formed on a heat-formable release sheet. A transfer sheet with an adhesive layer formed on the release sheet containing the pattern is placed facing the molded product so that the adhesive layer faces the molded product, and the peripheral edge of the transfer sheet is fixed. Then, by heating and pressing the transfer sheet against the upper surface of the molded product and adhering it to the suction table containing the molded product, the cross section surrounded by the upper surface of the suction table, the outer peripheral side of the molded product, and the transfer sheet is forms a substantially triangular space, the air in the substantially triangular space is exhausted from a suction hole provided in a suction table just below the outer peripheral edge of the molded product, and the transfer sheet is also attached to the outer peripheral side of the molded product. After fixing, the release sheet is removed from the surface of the molded product and the pattern is transferred.

(Operation) According to the above-mentioned means, a resin molded product 1 having an upper surface and an outer circumferential side, which have been molded in advance in a separate process, is preheated and placed so that its outer circumferential edge 4 is positioned on the suction table 2. The adhesive layer 15 is placed on the transfer sheet 8 in which an arbitrary pattern 14 is formed on a heat-formable release sheet 11 and an adhesive layer 15 is formed on the release sheet containing the pattern. A transfer sheet 8 is placed facing the molded product 1 with the peripheral edge thereof fixed so as to face the molded product 1, and the transfer sheet 8 is heated and pressed against the upper surface of the molded product 1, and the molded product 1 is heated. After adhering to the suction stand 2 containing As the air in the space 18 having a substantially triangular cross section defined by the side surface 19 and the transfer sheet 8 is exhausted, the transfer sheet 8 adheres and adheres to the lower edge of the outer peripheral side surface 19 of the molded product 1. . When the release sheet 11 of the transfer sheet 8 fixed to the outer surface of the molded product 1 is removed, the arbitrary pattern 14 is transferred not only to the upper surface 16 of the resin molded product 1 but also to the outer circumferential side surface 19.

(Example) Next, examples will be given and explained.

1 and 2 show a first embodiment of the present invention, in which a pattern is transferred to the outer surface of a cap 1 whose upper portion is flat.

Cap 1 is made of vinyl resin, polyethylene,
Polypropylene, styrene resin, polyamide,
It is molded from synthetic resin such as phenolic resin, and has the following properties: ease of welding of the transfer sheet,
Considering ease of operation, it is preheated to about 100°C and placed on the suction table 2. It goes without saying that the applicable cap 1 may be one whose surface has been subjected to primary application such as vapor deposition in advance.

The suction table 2 is formed with a protrusion 3 for positioning the cap 1, and when the cap 1 is placed, a plurality of suction holes 5 for exhaust gas are provided directly under the outer edge 4 of the cap 1. The vacuum chambers 6 inside the suction table 2 are connected to each other. An exhaust port 7 is opened in the vacuum chamber 6, and although not shown, it is connected to an exhaust system.

On the other hand, a transfer sheet 8 is disposed facing the suction table 2, with its peripheral edge being held by a fixed frame 9, and control heaters 10a, 10b, 10c for heating the transfer sheet 8 are installed on the transfer sheet 8. It is provided on the top and side of 8. These heaters are used as needed, and this figure is just one example. That is, the control heater is used so that when the transfer sheet 8 is attached to the cap 1, a predetermined deformation is caused in the transfer sheet 8 so that the pattern of the transfer sheet 8 becomes a desired pattern on the cap 1. However, in some cases, only the control heater 10a above the transfer sheet 8 may be used. Note that the control heater is energized as appropriate for the time required for desired heating.

As shown in FIG. 3, the transfer sheet 8 has a resin layer 1 on the upper surface of a release sheet 11 via a release agent layer 12
3, a pattern 14 is formed thereon, and an adhesive layer 15 is further formed on the entire surface of the resin layer 13 including the pattern 14. The resin layer 13 acts as a protective film to prevent the pattern 14 from being worn away or disappearing after the transfer, and may be omitted in some cases.

In this case, the release sheet 11 is made of polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polystyrene, etc., which are easily deformed by heating.

Further, the pattern 14 is formed by printing, drawing, painting, etc. using ordinary plastic printing ink or paint. The pattern on the transfer sheet 8 should be determined in consideration of expansion and deformation of the transfer sheet 8 due to suction, as will be described later. However, there is no need to consider locations where there is no deformation.

Further, examples of the material of the adhesive layer 15 include acrylic resin, vinyl resin, polyamide resin, phenol resin, etc., and are determined in consideration of weldability with the material of the resin molded product.

The transfer sheet 8 described above is prepared by placing the adhesive layer 15 facing the cap 1 placed on the suction table 2.
It is clamped to the fixed frame 9.

To transfer the pattern 14 of the transfer sheet 8 to the cap 1, the transfer sheet 8 whose peripheral edge is held by the fixed frame 9 is heated to a predetermined temperature above the softening point of the release sheet 11 using control heaters 10a, 10b, and 10c as appropriate. After heating to the temperature, it is preheated to about 100℃, and the suction table 2
Raise the cap 1 placed on the
The upper surface 16 of the transfer sheet 8 is pressed against the transfer sheet 8, and the transfer sheet 8 is further raised to adhere the peripheral edge of the transfer sheet 8 to the suction table 2.

Then, a space 18 having a substantially triangular cross section is formed between the upper surface of the suction table 2, the outer peripheral side surface 19 of the cap 1, and the transfer sheet 8. Thus, when the air in the triangular space 18 is exhausted through the suction hole 5 provided on the suction table 2, the transfer sheet 8 is also attached to the outer circumferential side surface 19 of the cap 1 and is fixedly integrated therewith. At this time, in the present invention, the outer peripheral edge 4 of the cap is
Since the suction hole 5 is provided in the suction stand 2 directly below, the transfer sheet 8 is reliably attached and fixed to the lower edge of the outer circumferential side surface 19. After that, by removing the release sheet 11 of the transfer sheet 8 stuck to the outer surface of the cap 1 and cutting off unnecessary parts of the transfer sheet 8, the cap 1 with the desired pattern 14 transferred thereto can be removed.
get.

In the above embodiment, a part (unnecessary part) of the transfer sheet 8 also adheres to the surface of the suction table 2, but if peeling of the sheet 8 is taken into account, the material of the suction table should not allow the sheet 8 to adhere. or select
It is desirable to apply a mold release agent on the suction table in advance.

In addition, in FIGS. 1 and 2, the resin molded cap 1 is raised toward the transfer sheet 8 side, and the transfer sheet is attached to the surface of the cap 1.
It is also possible to lower the transfer sheet 8 toward the cap 1 and attach the transfer sheet 8 to the surface of the cap 1.

FIG. 4 shows a second embodiment of the present invention, in which a transfer sheet 8 is attached and fixed to the surface of a hemispherical container 20 made of resin. Note that the control heater is not shown in this figure.

In FIG. 4, the hemispherical container 20 is placed on the mounting table 21 provided on the suction table 2'.
It is positioned by the positioning protrusion 3'.
In this case, the outer peripheral edge 4' of the container 20 and the peripheral side surface of the mounting table 21 are flush with each other, and suction holes 5' are radially opened just below the outer peripheral edge 4'. . If the mounting table 21 has such a structure, the second
Compared to the illustrated embodiment, the transfer sheet 8 can be more securely attached to the outer peripheral edge 4' of the container 20, which is preferable. Further, according to the second embodiment, since a part of the transfer sheet 8 does not adhere to the surface of the suction table 2', it is not necessary to peel the sheet 8 from the suction table 2'.

(Effects of the Invention) As explained above, according to the present invention, the resin molded product 1 is placed on the suction table 2, and the transfer sheet 8 having a fixed peripheral edge is heated and pressed against the molded product 1, and the The transfer sheet 8 is deposited on the suction table 2 containing the molded product 1 and is simply evacuated from the suction hole 5 provided in the suction table 2 directly below the outer peripheral edge 4 of the molded product 1.
can be reliably attached not only to the upper surface 16 of the molded product 1 but also to the lower edge of the outer peripheral side surface 19 thereof.

In particular, in the present invention, since the transfer sheet 8 is coated and transferred onto the preheated resin molded product 1, minute wrinkles or air bubbles do not occur between the molded product 1 and the transfer sheet 8, and precision is achieved. Achieves high quality and beautiful pattern transfer. In addition, in the present invention, even if the lower part of the outer peripheral surface of the molded product has a concave shape, it is possible to transfer it simply by suction means without the need for any special press molding means, and the method of the present invention can be carried out. It is also a simple device to use. As described above, the present invention allows the transfer sheet 8 to be easily attached and fixed to the outer surface of the resin molded product 1 without having to be molded to match the outer surface of the resin molded product 1, and moreover, the transfer sheet 8 can be easily attached and fixed to the outer surface of the resin molded product 1, and the transfer sheet 8 can be easily adhered to and fixed to the outer surface of the resin molded product 1. Since the process can be carried out separately, there is no delay in the molding cycle time.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the transfer process of the first embodiment of the present invention, in which FIG. 1 shows the state before the suction table is raised, and FIG. 2 shows the state after the suction table has been raised. The figure shows the state in which exhaust has started from the hole, Figure 3 is a cross-sectional view showing the structure of the transfer sheet, and Figure 4 is a second embodiment of the present invention, showing the outside of the resin molded product after almost complete exhaust. FIG. 3 is a cross-sectional view showing a state in which a transfer sheet is attached to the entire surface. 1... Cap, 2, 2'... Suction stand, 4,
4'... Outer edge, 5, 5'... Suction hole, 8...
Transfer sheet, 9...Fixed frame, 10a, 10b, 1
0c...Control heater, 11...Peeling sheet, 14
... Pattern, 15 ... Adhesive layer, 19 ... Outer peripheral side surface, 20 ... Hemispherical container.

Claims (1)

[Claims] 1. A preheated resin molded product having an upper surface and an outer circumferential side is placed so that its circumferential edge is positioned on a suction table, and an arbitrary pattern is formed on a heat-formable release sheet. A transfer sheet, in which an adhesive layer is formed on a release sheet containing a pattern, is placed facing the molded product so that the adhesive layer faces the molded product, and the peripheral edge of the transfer sheet is fixed. By heating the transfer sheet and pressing it against the upper surface of the molded article and adhering it to the suction table containing the molded article, the cross section surrounded by the upper surface of the suction table, the outer peripheral side of the molded article, and the transfer sheet is A substantially triangular space is formed, air in the substantially triangular space is exhausted from a suction hole provided in a suction table immediately below the outer peripheral edge of the molded product, and a transfer sheet is also attached to the outer peripheral side of the molded product. A method for transferring a pattern to a resin molded product, which comprises removing a release sheet from the surface of the molded product after fixation.