JPH1128856A - Transfer sheet for injection molding simultaneous in-mold decorating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform original small-scale production, sample preparation of many kinds in a small quantity, and transfer on a resin molded article of a curved face with a photograph level fine image by constituting a picture pattern on a picture pattern printing layer which needs a log of time and expenditure by means of an inkjet printer. SOLUTION: When a transfer sheet is printed by means of an inkjet printer from the ink receiving layer 6 side (an arrow mark A) to constitute a picture pattern and the picture pattern is observed on a molded article after the picture pattern is transferred, as it is to be observed from a release layer 3 side (an arrow mark B), a left and right reverse image (a mirror image) is required when the picture pattern is printed by means of the inkjet printer. In addition, it is necessary that the ink of the inkjet printer penetrates to the release layer side 61 of the ink receiving layer 6 and the printed picture image can be seen from the opposite face (the release layer side 61) of the printer printing face 62. It is necessary that the ink receiving layer 6 basically has a constitution wherein the ink is suitably absorbed and fixed and in general, it comprises pigments, a binder resin, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet for transferring a pattern of a transfer film onto a resin molded article at the same time as injection molding of the resin molded article, and to a painting forming method using the transfer sheet.

[0002]

2. Description of the Related Art Various methods such as printing, stamping, and transfer can be used for forming a pattern on the surface of a plastic molded product when the surface of the molded product is a flat surface or a quadratic curved surface. The pattern construction method in the case of having a three-dimensional curved surface is impossible by the above-described printing, stamping, etc.
At present, a method of simultaneously forming a transfer sheet on which a picture is printed at the time of molding is generally adopted as a mainstream method.

As shown in FIG. 1, a method of applying a transfer sheet to form a sheet is as follows: a base sheet 2 made of a plastic film having thermoformability;
A release layer 3 made of a resin having thermoformability is provided, a pattern printing layer 4 is provided on the release layer, and an adhesive layer 5 made of a resin having thermoformability and heat adhesion is further provided thereon. The transfer sheet 1 is constituted. Then, the adhesive layer surface 51 of the transfer sheet 1 is mounted in the gate direction of the injection molding die, that is, the adhesive layer 5 is fitted so as to match with the molded product, and the molded product is molded. A molded article with a picture is obtained by peeling the base sheet of the transfer sheet.

[0004] However, in the method shown in Fig. 1, although a picture can be applied to a molded article, the production of a transfer sheet requires a very large number of steps and time. In particular, a general printing method such as gravure or offset can be used to create the picture print layer, but any of them requires a lot of time and cost to create a printing original plate. Therefore, although it is efficient in mass production, it is extremely unsuitable for large-scale small-quantity production, especially sample production. In addition, the ink constituting the pattern printing layer also requires a special ink composed of a resin and a coloring agent, and therefore requires a certain production facility, and cannot be easily produced. Also, this method
Since the printing ink is transferred to the molded product together with the adhesive layer, there is no problem with simple pattern transfer, but there is a disadvantage that it is difficult to transfer a fine image. Further, in terms of the durability of the pattern after molding, there is a limitation in the constituent material, thickness, and the like of the release layer serving as the protective layer of the pattern, and there is a disadvantage that sufficient durability cannot be secured.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a method effective for mass production as shown in FIG. The purpose is to provide a transfer sheet for painting molding that transfers a fine image at the photographic level to a resin molding having a curved surface. It is an object of the present invention to provide a transfer sheet having a very high level of durability, with the greatest aim being to produce at a low cost in a short period of time, and depending on the structure of the transfer sheet.

[0006]

According to the present invention, there is provided a transfer sheet for painting and molding, wherein a picture of a picture printing layer, which requires a lot of time and cost, is constituted by an ink jet printer. The pattern printing layer of the present invention is a transfer sheet having a special configuration that can be printed by an ink jet printer. The configuration is a concept of the present invention, and will be described in detail with reference to the configuration shown in FIG. I do.

In FIG. 2, 2 is a base sheet made of a plastic film having thermoformability, 3 is a release layer made of a resin having releasability and thermoformability with respect to the base sheet 2, and 6 is a release layer. 3 is an ink receiving layer for absorbing and fixing the ink of the ink jet printer provided on the ink jet printer 3 and corresponds to a conventional pattern printing layer. Reference numeral 5 denotes an adhesive layer formed by post-processing after printing by an inkjet printer. The transfer sheet 1 thus configured is mounted on a mold with the adhesive layer surface 51 facing the gate direction of the injection mold, and after injection molding, the molded article with the transfer sheet is removed from the mold. Thereafter, the base material sheet 2 of the transfer sheet is peeled off to obtain a painted product.

It goes without saying that, in the finished painted product, the release layer 3 is on the front side of the painted product and the adhesive layer 5 is on the joint surface with the injection molded product. However, the following measures are required here.

That is, the first point is that the transfer sheet is printed from the ink receiving layer side 6 (arrow A) by an ink jet printer to form a pattern, and when the pattern is viewed from a molded product after the pattern transfer, a release layer is formed. Since the image is viewed from the third side (arrow B), a left-right inverted image (mirror image) is required when printing a picture with an ink jet printer, and the ink of the ink jet printer reaches the release layer side 61 of the ink receiving layer 6. It is necessary that the printed image penetrates and is visible from the side opposite to the printer printing surface 62 (the release layer side 61).

[0010] The second point is that the surface of the pattern transferred to the molded product is covered with the release layer 3, but the durability of the pattern surface is affected by the material and thickness of the release layer. Care must be taken in selecting the material for the release layer depending on the application.

As is apparent from this configuration, the present invention is based on the premise that the pattern printing layer is formed by an ink jet printer. Therefore, first, the pattern printing layer is formed on the release layer surface of the base sheet 2 provided with the release layer 3. It is necessary to configure the ink receiving layer 6 that can be printed by an inkjet printer. Many constitutions have been proposed for the ink receiving layer 6, but a constitution capable of appropriately absorbing and fixing the ink is basically required. Generally, a pigment, a binder resin, and other various additives are required. It consists of.

Examples of the pigment include silica, calcium carbonate, diatomaceous earth, aluminum oxide, and aluminum hydroxide. Examples of the binder resin include polyvinyl alcohol, polyvinyl pyrrolidone, a copolymer of acrylate, polyacrylamide, and ethylene-vinegar. Resins such as bi-copolymers can be used. Further, as additives, a water-proofing agent, an ultraviolet absorber, a preservative, an antioxidant, a pH adjuster, a surfactant, an antifoaming agent and the like are used in combination as required.

In these components, since the ink receiving layer 6 is deformed together with the base sheet 2 during injection molding, an ink receiving layer that can withstand a certain degree of deformation is necessary. The point is to configure However, when the amount of the binder resin added becomes extremely large, the ink absorption characteristics are reduced, and the image quality as an ink jet printer is reduced. It is preferable to select an appropriate one. Also, as mentioned earlier,
Since it is essential that the ink of the ink jet printer penetrates to the release layer side 61 of the ink receiving layer 6, it is necessary to adjust the amount of ink injected and the thickness of the ink receiving layer. That is, if the ink receiving layer 6 is too thick, the amount of penetration of the ink is small and the picture image is difficult to see, and if it is too thin, the ink is insufficiently absorbed and the picture image is easily blurred. Normally, when a commercially available ink jet printer is used, an ink receiving layer mainly composed of silica or polyvinyl alcohol needs to have a thickness of 20 to 30 μm.

On the other hand, the base sheet 2 serving as the base of the ink receiving layer 6 needs to have not only transport properties as a printer recording sheet but also stretchability by heat, that is, thermoformability (heat deformability). . Specifically, the material of the base sheet 2 can be a plastic film such as unstretched nylon, unstretched polyester, polyvinyl chloride, and PET. Among them, unstretched nylon and polyvinyl chloride are particularly preferable in terms of material. preferable. That is, they have a relatively low heat deformation temperature, can be stretched by pulling during molding, and have an injection molded product for appearance, so the resin material is often AS, ABS resin, etc. Because of low-temperature molding, uniform transfer can be performed. Further, the thickness of the base sheet 2 is suitably about 50 to 200 microns, though it depends on the size of the aperture on the curved surface and the transport characteristics of the printer. Of course, it is possible to use a thin sheet of 50 μm or less, if the transportability of the printer is permitted. In particular, when the base sheet 2 is 5
If the sheet is as thin as 0 μm or less and has difficulty in transporting the printer, as shown in FIG. 3, an auxiliary sheet 7 having a slight tackiness that can be easily peeled off is attached to the base sheet 2 and the sheet thickness is reduced. After securing the printer and carrying it,
The problem relating to the thickness of the base sheet can be solved. In particular, the thickness of the substrate sheet 2 is large enough to be deformed and is 10 to 20 μm.
This configuration is very useful when m is required.

The release layer 3 formed between the base sheet 2 and the ink receiving layer 6 is for easily peeling the base sheet 2 and the ink receiving layer 6 provided with a pattern after injection molding. In addition, it is necessary to have releasability from the base material sheet 2 and, after transfer, it becomes the surface of a molded product, so that abrasion resistance, weather resistance and the like are required. Materials that can be used for the release layer 3 are thermoplastic acrylic resin, cellulose resin, vinyl chloride / vinyl acetate resin, thermoplastic polyester resin,
Thermoplastic resin such as thermoplastic urethane resin, chlorinated rubber, polyolefin resin, silicone resin as the main component,
Further, a composition to which additives such as a plasticizer, an ultraviolet absorber, and a film reinforcing agent are added can be used.

Next, a pattern image is printed on the base sheet 2 on which the ink receiving layer 6 is formed by an ink jet printer.
Further, an adhesive layer 5 is formed on the printing surface side. As a material constituting the adhesive layer 5, a resin having a thermal adhesive property with an injection molding resin and having a thermoforming property, for example, an ABS resin, a styrene resin, a thermoplastic acrylic resin, a vinyl chloride resin, and acetic acid Although a thermoplastic resin such as a vinyl resin can be used, a resin having good compatibility with the molding resin and softening at a lower temperature than the molding resin is preferable.

The above is the basic structure of the present invention. In the use of this transfer material, for example, in the injection molding die shown in FIG. The position is determined and arranged on the surface on which 9a is formed. That is, the mounting is performed such that the joint surface with the molded product 10 is on the adhesive layer side. By this molding, the resin of the injection molding and the adhesive layer 5 of the transfer sheet are joined at the time of molding, and are integrated with the molded product, and the pattern is transferred from the flat sheet to the molded product having the curved surface. That is, the transfer sheet is formed into a shape along the mold surface of the mold by heat and pressure during injection molding.

The thus-painted molded product is taken out of the molding die, and the finished product is obtained by peeling the base sheet.

The ink receiving layer 6, the release layer 3, and the adhesive layer 5 may be formed from a continuous coating device such as a roll coater to a small coating device such as a hand coater such as a bar coater, or offset printing. Since any printing apparatus such as screen printing can be used, a production scale or a hand-held available apparatus can be appropriately selected and used.

As described above, according to the present invention, a pattern printing layer in a transfer sheet for painting molding is constituted by an ink receiving layer, and a high-level planar image is formed by an ink jet printer.
It can be transferred to a resin molded product having a three-dimensional curved surface. However, the structure, material, and thickness of the transfer sheet, the shape of the transferred object (molded product), the depth of irregularities, the material of the molded product, and the molding It is necessary to change the configuration of the transfer sheet depending on the temperature, the required quality such as the finished quality of the transfer, and the like.

For example, in a case where the base sheet 2 of the transfer sheet 1 is thin and it is difficult to convey the sheet by the ink jet printer, the structure of the transfer sheet shown in FIG. 3 is effective. In this structure, as described above, the auxiliary sheet 7 having a slight adhesive property that can be easily peeled off is attached to the base sheet 2 and the sheet is transported after securing the sheet thickness. This configuration is very useful when a substrate having a large thickness and a thin base sheet 2 is required.

In the case where the molded product after the pattern transfer is required to have particularly high durability such as friction resistance and scratch resistance on the surface of the pattern,
As shown in FIG. 4, a pattern protection sheet 8 is provided between the release layer 3 and the ink receiving layer 6, and after injection molding, the base sheet 2 is peeled off from the surface of the pattern protection sheet 8 so that the pattern is securely formed. A configuration that can be protected can be realized. In this case, the material of the picture protection sheet 8 may be the same as that of the base sheet 2,
In consideration of deformation during molding, it is preferable that the pattern protection sheet 8 and the base sheet 2 are made of the same material. Of course, it is needless to say that the picture protection sheet 8 needs to be transparent. Also, the peeling layer contact surface side 8 of the picture protection sheet 8
By forming the surface of No. 1 with a glossy surface, it is possible to obtain a molded product having a high gloss surface with a flat feeling on the surface of the painted molded product.

Further, as an example of a method of using the transfer sheet of the present invention, for example, a width of 100 mm and a length of 1 m
Prepare a sheet (transfer sheet having a base sheet, a release layer, and an ink receiving layer) before forming the adhesive layer, and print 10 images on the sheet at different intervals of 50 × 50 mm with an appropriate image by an inkjet printer. Then, after forming the adhesive layer, it is set in a molding die and is repeated 10 times in a cycle of one molding and one image, so that ten painting molded products can be obtained one by one in a short time.

The above is the description of the basic mode of the present invention.
Hereinafter, a specific embodiment will be shown, and the effect will be described in more detail.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below more specifically.
In FIG. 4, reference numeral 2 denotes a base sheet made of a plastic film having thermoformability, and reference numeral 6 denotes an ink receiving layer by an ink jet printer, which corresponds to a conventional picture printing layer. Reference numeral 7 denotes an auxiliary sheet, and reference numeral 8 denotes a picture protection sheet. The details of the configuration are as described above.

In this basic configuration, a painting transfer sheet was prepared under the following various conditions, and transfer was performed by injection molding.

(First Embodiment) In this embodiment, a transfer sheet having the structure shown in FIG. 2 was implemented. An acrylic-urethane-based release layer was applied to a base sheet having the following thickness using a bar coater. Prepare a film provided with, on the release layer,
After forming an ink receiving layer so as to have a solid component amount as shown in Table 1 and drying, a color landscape image was printed with a commercially available ink jet printer, and a vinyl acetate-based adhesive layer was formed on the upper surface of the image to form a transfer sheet. This transfer sheet was mounted so that the adhesive layer side was the mold gate side, that is, the joining surface with the molded product, and the material of the molded product was injection molded with ABS resin using a simple mold.

Base sheet Unstretched nylon film 30 μm, 80 μm, 10
0 μm Ink-receiving layer (mixed as a solid component) 50% silica as a pigment, 45% polyvinyl alcohol as a binder resin, and 5% other (waterproofing agent, surfactant) in solid component amount Molding mold R30mm three-dimensional Injection mold having a curved surface and a step having a draft angle of 5 degrees and a height of 5 mm The transfer result of this example is a non-stretched nylon film.
Those having a size of 0 and 50 µ could be transferred without any problem. In the case of 100 μm, fine mold scratches occurred at the step portion of the injection mold, but in the case of 30, 50 μm, transfer was possible without occurrence of scratches.

For this reason, when a relatively thick base sheet is used as the transfer sheet with the protective layer, a molded article having a transfer surface with a small step is preferred.

The transferred picture image was relatively soft, such as a piece of wood, and was not scratched when rubbed lightly, but was sharply rubbed with a sharp sharp tip.

Further, a non-stretched nylon film 30 μm
In the case of m, it was difficult to feed accurately when conveyed by a printer, and the pattern image was slightly disturbed.

(Second Embodiment) In this embodiment, a transfer sheet having the structure shown in FIG. 3 is implemented. In the first embodiment, a substrate sheet having a thickness of 30 μm is defective in conveyance by a printer. In the case where the thickness of the base sheet is 30 μm, a release layer, an ink receiving layer, and an adhesive layer are formed under the same conditions as in the first embodiment, and the base sheet has a slight tackiness as shown in FIG. A transfer sheet was formed by laminating an adhesive sheet of 100 μm in thickness as an auxiliary sheet to a base sheet, and was conveyed by a printer.

(Third Embodiment) In this embodiment, a transfer sheet having the structure shown in FIG. 4 is used. In the first embodiment, a picture image after transfer is hardly rubbed with a sharp and sharp object. In order to improve this point, a pattern protection sheet 8 having a thickness of 20 μm made of the same stretched nylon film as the base sheet 2 was provided between the release layer 3 and the ink receiving layer 6. A release layer, an ink receiving layer, and an adhesive layer were formed under the same conditions as in the first embodiment, and the transfer sheet was injection-molded to form a transfer picture image, and the durability of the surface was confirmed. A difficult painted product was obtained.

[0034]

As described above, according to the transfer sheet for painting and molding of the present invention, a high-level printed fine image by an ink jet printer can be obtained very easily. In particular, in the case of a transfer sheet constituting a pattern protection sheet, it is possible to provide a painted molded article having a high pattern durability and a high pattern durability with a high level of print definition image.

In addition, the transfer sheet can be prepared in a very short time because the time required for preparing a conventional printing plate is not required in the preparation time. Since there is no such material, a great effect is produced, such as very low-cost production.

These features are very useful because they are suitable for the most demanded original products of various kinds and small-scale production, or for the preparation of many kinds of samples in units of several units.

[Brief description of the drawings]

FIG. 1 is a sectional structural view showing the structure of a conventional general transfer sheet for painting and molding.

FIG. 2 is a cross-sectional structural view showing the structure of a transfer sheet for decorating molding according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional structural view showing a structure of a transfer sheet for decorating molding according to a second embodiment of the present invention.

FIG. 4 is a sectional structural view showing the structure of a transfer sheet for decorating molding according to a third embodiment of the present invention.

FIG. 5 is a sectional structural view showing a state at the time of molding of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transfer sheet 2 base sheet 3 release layer 4 pattern printing layer 5 adhesive layer 6 ink receiving layer 7 auxiliary sheet 8 picture protection sheet 9 molding die 9a die gate 10 molded product

Claims (4)

[Claims] 1. A transfer sheet for painting and forming comprising a base sheet, a release layer, a pattern printing layer and an adhesive layer, wherein the pattern printing layer is constituted by an ink receiving layer which is printable by an ink jet recording apparatus, and a printing surface is formed. A transfer sheet for simultaneous injection molding painting, characterized in that the opposite side is the surface side of the painting molding. 2. The transfer sheet for simultaneous injection-molding and painting according to claim 1, wherein an auxiliary sheet having slight adhesiveness is provided on the base sheet. 3. The transfer sheet for simultaneous injection molding painting according to claim 1, wherein a picture protection sheet is provided between the base sheet and the picture printing layer. 4. The transfer sheet for simultaneous injection-molding and painting according to claim 3, wherein the surface of the pattern protection sheet on the release layer contact surface side is a glossy surface.