JPH0242080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer material for painting at the same time as molding, and more specifically, a method for painting at the same time as molding, that is, a method for transferring and painting a design onto the surface of a plastic molded product at the same time as the molding. The present invention relates to a transfer material for painting at the same time as molding that can be used.

It is an object of the present invention to provide a transfer material for painting at the same time as molding, which makes it possible to accurately transfer and paint a design onto a predetermined position of a plastic molded product.

Conventionally, methods for providing designs on the surface of plastic molded products include the so-called post-molding direct printing method, in which designs are printed on the surface of a pre-formed molded product by screen printing, etc.; The so-called post-forming transfer printing method uses hot stamping foil to create a design using heat and pressure, or a sheet with a desired design printed on it.
There is a so-called insert molding method in which the sheet is temporarily attached in a molding die by electrostatic force or the like, and then a molding resin is injected into the mold to fuse and integrate the sheet simultaneously with the molding of a plastic molded product.

However, all of the above methods have the following drawbacks. That is, in the case of the direct printing method after molding, it is necessary to use ink containing a solvent that has a slow drying rate, so not only is it impossible to stack the molded products immediately after printing, but also the ink must be dried after printing. Depending on the type of molding resin, the solvent in the ink can easily cause cracks on the surface of the molded product, and in the case of the post-molding transfer printing method, the molding process and transfer printing In addition, in the case of the insert molding method, it is extremely difficult to temporarily attach the sheet to the predetermined position in the mold, and the resulting molded product Each method has major drawbacks, such as not only the pattern on the surface being easily misaligned, but also the fact that the sheet is fused to the molded product, so it cannot be applied to molded products with holes. It is something that you have. Furthermore, all of the methods described above can only apply designs to molded products that have a simple plane or quadratic curved surface, and cannot be applied to three-dimensional molded products that have minute irregularities or curved surfaces. It is something.

On the other hand, as other means for providing designs on molded products, for example, JP-A-48-43760, JP-A-49-105856
Publication No. 151596, Japanese Patent Application Publication No. 151596, Japanese Patent Application Publication No. 1987-
A method disclosed in Japanese Patent No. 195683 is known. These methods show a method of performing transfer printing at the same time as molding, and unlike the three methods described above, these methods can also be applied to three-dimensional molded products exhibiting uneven portions and curved surfaces.

However, the techniques disclosed in these publications were merely invented to solve the technical problem of how to form a pattern on the surface of a three-dimensional molded product exhibiting uneven parts and curved parts. To explain this point in more detail, for example, JP-A-48-43760 and JP-A-49-105856 simply show a method for performing transfer printing within a mold at the same time as molding. Therefore, there is a lack of knowledge regarding the selection of the base sheet of the transfer material and the layer structure. In addition, Japanese Patent Application Laid-Open Nos. 56-151596 and 1987-195683 disclose methods that enable transfer printing on three-dimensional molded products that have complex curved surfaces with larger steps. , a plastic film with a high elongation rate is used as the base sheet of the transfer material, and in some cases, the transfer material is heated before injection molding so that the entire transfer material is easily stretched in the mold during injection molding. It describes how to do this. In other words, this is a concept that can be applied to three-dimensional molded products that exhibit complex curved surfaces with larger unevenness and steps.

However, the technology related to the method of performing transfer printing at the same time as conventional molding is a research on painting techniques for three-dimensional molded products with large unevenness, and it is difficult to accurately place a predetermined position on a three-dimensional molded product. It was not invented to solve the technical problem of how to form a positioned pattern; therefore, no research has been conducted to date on molding and simultaneous transfer painting technology for the purpose of highly accurate pattern alignment. The reality is that it is not.

Therefore, in order to solve the various problems mentioned above, the inventor of the present invention has finally completed the present invention as a result of intensive research and experiments on molding simultaneous transfer painting technology from a viewpoint that has not received any attention up to now. It is something. That is, the present invention provides a transfer material for simultaneous molding and painting in which a transfer layer is formed on a base sheet, in which the base sheet does not exhibit elasticity with respect to heat and tension in the transfer material manufacturing process and does not exhibit elasticity in the injection molding process. This is a transfer material for painting at the same time as molding, which is characterized by being a plastic film that exhibits plasticity with respect to the heat quantity and injection pressure of the molten resin.

Hereinafter, the transfer material for decorating while molding according to the present invention will be explained in more detail with reference to the drawings.

The transfer material 1 according to the present invention is formed by forming a transfer layer 5 such as a pattern layer 3 and an adhesive layer 4 on a base sheet 2 (see FIG. 1).

The base sheet 2 used in the present invention does not show elasticity against the heat and tension in the transfer material manufacturing process and the tension when setting the transfer material 1 in the injection molding process, and does not show elasticity against the heat and tension in the transfer material manufacturing process and the tension when setting the transfer material 1 in the injection molding process. It is a plastic film that shows plasticity with respect to heat and injection pressure. In other words, when printing and drying each layer of the transfer material in the transfer material manufacturing process, and when setting the transfer material in the injection molding process, it has excellent dimensional stability and enables highly accurate positioning. When molding resin is injected into the cavity, elongation occurs in areas where the transfer material is forced to elongate, such as the rising edges of irregularities and the R portion (boundary line between surfaces). It's like a plastic film. Examples of such plastic films include biaxially oriented polyester films, biaxially oriented nylon films, and laminate films of biaxially oriented polyester films and biaxially oriented nylon films. The reason why the base sheet 2 as described above is used in the present invention is as follows. That is, the base sheet of the transfer material for painting at the same time as molding is usually a plastic film with excellent elasticity, such as an unstretched polyester film, in order to conform as much as possible to the irregularities and curved surfaces of the surface of the three-dimensional molded product. , unstretched nylon film or polyvinyl chloride film, etc.;
It easily deforms due to its weak mechanical strength against tensile force, and has poor dimensional stability due to its low heat resistance, making it difficult not only to print precise register patterns in the printing process but also to prevent molding during injection molding. The base sheet itself is easily deformed as a whole along the resin flow, resulting in deformation of the design, and the deformation of the base sheet is particularly concentrated in areas where weld lines occur, causing the problem of wrinkles. This is because it has become clear that the easy-to-stretch property actually appears as a drawback.

The thickness of the base sheet 2 used in the transfer material 1 of the present invention should be selected depending on the shape of the molded product, but the usable range is about 20 to 100 μm, preferably 25 to 75 μm. is suitable.

An important point in the transfer material 1 for simultaneous molding and painting according to the present invention is the use of the base sheet 2 described above. The anti-fusing layer 6 described in 2 can be provided. This anti-fusing layer 6 is a layer for preventing the base sheet 2 and the transfer layer 5 from being fused together in the portion where the base sheet 2 exhibits plasticity during injection molding and is stretched. That is, if this anti-fusing layer 6 is not provided, the uneven rising portions and R
In the areas where the transfer material 1 is forced to elongate, the base sheet 2 and the layer printed on the base sheet are significantly stretched, and a newly activated surface appears, causing the base sheet 2 to elongate. The transfer layer 5 and the transfer layer 5 may be fused together (see Figures 2-a and 2-b), and in order to prevent this, in the present invention, a fusion protection layer 6 is formed. It is something.

The material that can be used for this anti-fusing layer 6 is a resin that hardens by crosslinking, that is, a resin that is extremely stable against heat and forms an inert surface. thermosetting resins such as melamine resins, urea resins, benzoguanamine resins, epoxy resins, thermosetting acrylic resins, urethane resins, polyester resins, alkyd resins, or two-component curable resins. In addition, there are acrylic resins, urethane resins, acrylic urethane resins, ultraviolet curable resins based on epoxy resins, and electron beam curable resins designed to be cross-linked and cured by irradiation with ultraviolet rays or electron beams. . The reason why the above-mentioned resin is used as the anti-fusion layer 6 is that the anti-fusion layer 6 is applied to the substrate in areas where the elongation of the transfer material is forced, such as the raised areas of unevenness and R areas in the mold during injection molding. The inventor of the present invention found that although cracks occur due to the inability to follow the elongation of the sheet, the cracks are very small and the surface is inert, so the anti-fusing effect is maintained. This is because it was discovered from numerous experimental examples by (see Figures 3-a and 3-b),
When these curable resins are actually used, it is preferable to mix thermoplastic resins with the curable resins alone or in a mixture of two or more of them, taking into account suitability for coating, within a range that does not impair the anti-fusion function. Furthermore, the surface of the molded product can be finished in a matte state by blending an inorganic filler such as finely powdered silica, talc, clay, calcium carbonate, or precipitated barium sulfate. There are coating methods such as gravure coating and bar coating as means for providing the anti-fusion layer 6, and this is usually carried out in a separate process prior to printing the pattern layer 3.

The transfer material 1 for painting at the same time as molding according to the present invention is provided on the base sheet 2 on which the above-described base sheet 2 and anti-fusing layer 6 are formed, a mold release protective layer 7, a pattern layer 3,
An adhesive layer 4 and the like are provided.

The release protective layer 7, the pattern layer 3, and the adhesive layer 4 will be explained in this order below.

First, the mold release protective layer 7 is for easily separating the base sheet 2 and the transfer layer 5 after the injection molding process. Materials that can be used for the mold release protective layer 7 include thermoplastic acrylic resin, cellulose resin, vinyl chloride/vinyl acetate copolymer resin, thermoplastic polyester resin, thermoplastic urethane resin, chlorinated rubber, and chlorinated polyolefin. A composition containing a thermoplastic resin such as a thermoplastic resin as a main component and further additives such as a coloring agent, a plasticizer, a film strengthening agent, and an ultraviolet absorber can be used.

Since the mold release protective layer 7 becomes the surface of the molded product after the injection molding process, it is required to have various properties such as wear resistance, scratch resistance, and chemical resistance.

Next, the pattern layer 3 is provided on the release protection layer 7, or on the fusion prevention layer 6 if the release protection layer 7 is not provided. Materials used for this pattern layer 3 include thermoplastic acrylic resin, cellulose resin, vinyl chloride/vinyl acetate copolymer resin, thermoplastic urethane resin, chlorinated rubber, chlorinated polyolefin resin, thermoplastic polyester resin, and polyamide resin. A binder made of one or more thermoplastic resins such as resins, petroleum resins, and natural resins, inorganic pigments such as titanium oxide, carbon black, and Bengara, and phthalocyanine, azo, anthraquinone, and triphenylmethane dyes. It is possible to use a composition comprising organic dyes such as pigments, quinacridone resins, and dioxazine pigments, and auxiliary agents such as dispersants, antifoaming agents, and plasticizers.

Furthermore, an adhesive layer 4 is provided on the pattern layer 3. The material used for this adhesive layer 4 has a softening point lower than the melting temperature of the molding resin used during injection molding, and is compatible with the molding resin, so it can be thermally bonded to the molding resin. It is necessary that the Examples of such materials include ABS resin, styrene resin, thermoplastic acrylic resin, polycarbonate, cellulose resin, vinyl chloride/vinyl acetate copolymer resin, polyamide resin, polyester resin, cyclized rubber, chlorinated polyolefin, and petroleum. Main ingredients include resin, natural resin, etc.
If necessary, various coloring agents and auxiliary agents may be blended in the same manner as in the ink composition used for the pattern layer 3.

The transfer material for painting while molding according to the present invention has the above-described structure. When using this transfer material, for example, first, a long transfer material with a pattern printed on it is installed in the transfer material feeding device attached to the injection molding machine, and then the male and female molds of the injection mold are placed. During each molding cycle, the transfer material is fed so that the adhesive layer faces the gate part of the mold, and after accurately positioning it with respect to the cavity part in the mold corresponding to the molded product, the mold is The mold is closed, and then molten molding resin is injected into the cavity, and after cooling, the base sheet is peeled off using the mold opening action of the mold. By doing so, it is possible to obtain a molded article with a transferred design.

Next, specific examples will be given and explained. However, all "parts" represent "parts by weight."

<Example 1> An anti-fusion layer with a thickness of 2 μm was formed by gravure coating using an ink having the composition below on biaxially stretched polyester film #50 that had been subjected to corona discharge treatment, and the film was heated at an ambient temperature of 180°C. After curing for 20 seconds in A pattern layer having four colors in register was formed thereon, and an adhesive layer was further formed thereon by the same gravure coating method using ink having the composition shown below.

Melamine resin 80 parts Epoxy resin 20 parts Toluene/MEK (methyl ethyl ketone) = 1/
1 200 parts Thermoplastic acrylic resin 70 parts Vinyl chloride/vinyl acetate copolymer resin 30 parts Polyethylene wax 3 parts Toluene/MEK=1/1 200 parts Thermoplastic acrylic resin 30 parts Chlorinated rubber 30 parts Pigment 30 parts Chlorinated paraffin 5 parts Surfactant 0.5 parts Toluene/ethyl acetate = 3/7 260 parts Styrene resin 20 parts Toluene/ethyl acetate = 1/1 80 parts After setting the transfer material with the above structure in the injection molding machine and positioning it. The mold was closed, and styrene resin molten at 200°C was injected into the cavity. After cooling, the mold was opened and the base sheet to which the anti-fusing layer was adhered was peeled off to obtain a molded product with the pattern transferred thereon. The shape of this molded product has a height of 4 mm and a corner R (radius) of 2
It is a rectangular remote control switch panel with a diameter of 50 mm on one side, 150 mm on the other side, and a resin thickness of 1.5 mm, with a scale plate formed on it. After molding, we measured the scale position of this dial and found that it was transferred to the specified position of the molded product with a positional accuracy of ±0.1mm, and the design was also beautifully transferred to the corners and sides. It was hot.

<Example 2> On biaxially stretched polyester film #25 that has not been subjected to corona discharge treatment, a fusion prevention layer is formed using an ink having the following composition, and a pattern layer is formed on top of the anti-fusing layer using an ink having the following composition. An adhesive layer was formed thereon using an ink having the composition shown below.

Urea resin (urea, formaldehyde condensate) 60 parts Epoxy resin 20 parts CAB (cellulose acetate butyrate) 20 parts Acid catalyst (curing agent) 5 parts Methanol/MEK=4/1 200 parts Vinyl chloride, vinyl acetate, maleic acid Polymer resin 30 parts Thermoplastic acrylic resin 70 parts Pigment 50 parts Adipate ester plasticizer 10 parts Dispersant 0.3 parts MIBK (methyl isobutyl ketone)/MEK=
1/1 200 parts ABS resin 50 parts Petroleum resin 10 parts Pigment 20 parts Toluene/ethyl acetate = 3/7 200 parts The transfer material having the above structure was set in the injection molding machine in the same manner as in Example 1, and then positioned. Then, the mold was closed, ABS resin molten at 230°C was injected into the cavity, and after cooling, the mold was opened and the base sheet was peeled off to obtain a molded product with the pattern transferred. A fusion prevention layer appears on the surface of this molded product, and its shape is a flat plate with a resin thickness of 2 mm, the parting line is 1 mm below the top surface, and the R (radius) of the outer periphery.
is 0.5mm, the radius of the corner of the opening is 0.1mm, and the parting line is 0.5mm below the top surface.When we measured the positional accuracy in the same manner as in Example 1, we found that the molded product It is transferred with a positional accuracy of ±0.1mm to the specified position of the corner, side,
The design was also beautifully transferred to the corners and sides of the opening.

<Example 3> An anti-fusing layer was formed on corona discharge treated biaxially oriented polyester film #75 using an ink having the following composition by a reverse coating method,
After drying at an ambient temperature of 150℃ for 20 seconds to accelerate curing,
After being left at room temperature (approximately 25°C) for 5 days (the thickness of the coating after drying is 3 μm), a release protective layer was formed thereon using the same ink as in Example 1, and then Example A pattern layer was formed using the same ink as in Example 1, and an adhesive layer was further formed thereon using an ink having the composition shown below.

Urethane resin 90 parts Finely powdered silica 10 parts Toluene/ethyl acetate/vinyl acetate = 4/3/
3 200 parts Chlorinated polypropylene 20 parts Toluene 80 parts The transfer material having the above structure was set in the injection molding machine and positioned in the same manner as in Example 1, and then the mold was closed and molten polypropylene resin was injected into the cavity. After cooling, the mold was opened and the base sheet was peeled off to obtain a polypropylene washing machine instrument panel with a transferred design. The shape of this instrument panel is 300
It is a rectangle of mm x 100mm with a rising edge of 5mm, a resin thickness of 2mm, and an outer circumference R (radius) of 1.5mm. Furthermore, there are 17 circular and rectangular openings, and the opening radius is 1.5mm.
(Radius) 0.2 mm to 2 mm, and the parting line ranged from 0.3 mm to 2 mm from the top surface. Example 1
When we measured the positional accuracy in the same way as above, we found that the pattern was transferred with a positional accuracy of ±0.1mm to the specified position on the molded product, and the design was also beautifully transferred to the corners, sides, and sides of the opening. It was hot.

<Comparative Example> Using a transfer material in which a pattern layer and an adhesive layer having the same composition as in Example 1 were formed on unstretched polyester film #50 that had been subjected to corona discharge treatment,
The rest was carried out in the same manner as in Example 1.

In the multicolor printing process, the registration of each color is difficult to match, and when measuring the design size of the transfer material, the original size is 100.
There was expansion and contraction of ±0.5 mm or more with respect to mm. Furthermore, when the scale position of the scale plate was measured after molding, it was found that there was a positional deviation of ±0.5 mm or more from the predetermined position of the molded product.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the transfer material according to the present invention, FIG.
Figure 2-b is a schematic cross-sectional view of the base sheet after peeling when injection molding is performed using a conventional transfer material, and Figure 3-a is a schematic cross-sectional view of the base sheet when injection molding is performed using the transfer material according to the present invention. Schematic cross-sectional diagram near the R part in case 3-b
The figures each show a schematic cross-sectional view of the base sheet after peeling when injection molding is performed using the transfer material according to the present invention. In the figure, 1... transfer material, 2... base sheet, 3...
...Design layer, 4...Adhesive layer, 5...Transfer layer, 6...
...Fusion prevention layer, 7... Mold release protective layer, 8... Molded article.

Claims (1)

[Scope of Claims] 1. In a transfer material for simultaneous molding and painting in which a transfer layer is formed on a base sheet, the base sheet does not exhibit elasticity against heat and tension during the transfer material manufacturing process, and does not exhibit elasticity during the injection molding process. A transfer material for painting at the same time as molding, characterized in that it is a plastic film that exhibits plasticity with respect to the heat quantity and injection pressure of the molten resin. 2. Claim 1, wherein the base sheet is a biaxially stretched plastic film.
Transfer material for painting at the same time as molding as described in section. 3 The base sheet is a plastic film that does not show elasticity against the heat and tension in the transfer material manufacturing process, but shows plasticity against the heat amount and injection pressure of the molten resin in the injection molding process, and an anti-fusing layer is formed on the plastic film. A transfer material for painting at the same time as claimed in claim 1, characterized in that the transfer material is formed by: 4. The transfer material for painting while molding as set forth in claim 3, wherein the base sheet is a biaxially stretched plastic film on which a fusion prevention layer is formed.