JPH02261614A - In-mold transfer foil - Google Patents

Abstract

PURPOSE:To obtain in-mold transfer foil, which enables the stable and desired transfer over the whole region to be transferred by a structure wherein heat resistant layer is provided at least at the position corresponding to the gate part of an injection mold between base material film and heat-sensitive adhesive layer. CONSTITUTION:The in-mold transfer foil 1 concerned consists of base material film 2, at least transfer layer 3 and heat-sensitive adhesive layer 4, both of which are laminated to the base material layer 2 in the order named, and heat resistant layer 5, which is provided at the predetermined part between the base material film 2 and the heat-sensitive adhesive layer 4. The heat resistant layer 5 is provided at least at the position corresponding to the gate part 7 of an injection mold between the base material film 2 and the heat-sensitive adhesive layer 4 or concretely between releasing layer 6 and transfer layer 3, between the transfer layer 3 and the adhesive layer or the like. As the material for the heat resistant layer 5, resin material excellent in heat resistance such as material mainly made of urethane-based one or the like is used. By employing the transfer foil concerned, since heat resistant layer presents at the position corresponding to the gate part 7 without fail, the bleeding of ink at the pouring of molten resin from the gate part 7 can be prevented from occurring.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an in-mold transfer foil.

[Conventional technology and the problem to be solved by the invention]

In recent years, transfer foils have been developed by sequentially laminating a transfer layer, such as a pattern layer, a metal vapor deposition layer, etc., and a heat-sensitive adhesive layer on a base material, and are used as a molding material when placed in an injection mold. In-mold transfer foils are used that can transfer a desired transfer layer to the surface of an injection molded product by injecting and filling a molten resin into the mold, removing the mold, and then peeling off the base material.

When this type of in-mold transfer foil is actually transferred,
Particularly, a part of the transfer layer and adhesive layer located at a position corresponding to the gate part for injecting the molten resin into the two molds is damaged by the heat and injection pressure of the molten resin injected from the gate part.
There was a problem that "ink flow" occurred, and as a result, it was impossible to perform the desired transfer.

Therefore, in order to prevent ink flow during transfer as described above, in-mold transfer foils have been known in which a transfer layer and a heat-sensitive adhesive layer are formed of a resin material with a relatively high glass transition temperature. However, with this transfer foil, particularly if the drying of the ink in each layer after application is insufficient, ink still flows in the layer corresponding to the vicinity of the gate portion.

The present invention has been developed in view of the above points, and is capable of suppressing the flow of ink on the transfer layer, etc., especially near the gate portion during transfer, thereby stably performing the desired transfer over the entire area corresponding to transfer. The purpose of the present invention is to provide an in-mold transfer foil that can be used as an in-mold transfer foil.

[Means to solve the problem]

That is, the present invention provides: (1) A transfer foil formed by sequentially laminating at least a transfer layer and a heat-sensitive adhesive layer on a base material soy 5lum, which is placed in an injection mold so that the heat-sensitive adhesive layer side In the in-mold transfer foil, in which the transfer layer is transferred to the surface of the injection-molded product by injection-filling with a molten resin, at least the gate part of the injection mold is formed between the base film and the heat-sensitive adhesive layer. An in-mold transfer foil characterized by having a heat-resistant layer provided at corresponding positions.

(2) The in-mold transfer foil according to claim 1, wherein the outline of the heat-resistant layer is formed by blur printing.

(3) Claim 1 or 2 in which the heat-resistant layer is not provided at a position corresponding to a corner portion of the injection molded product where drawability is required.
In-mold transfer foil as described.

(4) Claims 1 to 3 in which the heat-resistant layer is formed from a thermoplastic vehicle to which isocyanate is added to impart heat resistance.
The in-mold transfer foil described in any of the above.

The main points are as follows.

C Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and the in-mold transfer Fi 1 of the present invention basically includes a base film 2,
The film shown in FIG. 6 indicates a release layer, and this release layer allows the base film 2 to be peeled off during transfer between the film 2 and the release layer 6.
It is done between.

The base film 2 may be any film that has mold releasability and is used as a base material for ordinary transfer foils, for example, for the purpose of transferring a transfer tank with high dimensional accuracy to the surface of a molded product with a shallow drawing shape. Therefore, it is preferable to use a resin film made of polyethylene terephthalate, polycarbonate, polyimide, polyarylate, polyether ether ketone, cellulose acetate, etc., which does not easily change dimensions due to heat or stress. Vinyl chloride, polyamides (e.g. 6-nylon, 6.6-nylon, etc.), vinylon, polyolefins such as polyethylene and polypropylene, low-crystalline polyesters such as polyethylene terephthalate/isophthalate copolymers, polybutylene lenticulate, etc. A flexible thermoplastic resin film or a laminate thereof is preferred, and the thickness of the film 2 is usually 5 to 200 μm, preferably 12 to 5 μm.
It is 0 μm.

The peeling layer 6 facilitates peeling from the base film 2 and performs a surface protection function to prevent the transfer N3 from being hidden after transfer. The release layer 6 is made of, for example, a resin material such as acrylic resin, vinyl chloride-vinyl acetate copolymer, polyethylene, or epoxy. It is formed by coating using a printing method.

The transfer layer 3 is a layer that performs the function of imparting design properties to the injection molded product that is the material to be transferred, and specifically includes a pattern layer, a colored layer, a metal vapor deposition layer, etc. It is constructed by appropriately combining one type or two or more types. Further, the transfer layer 3 may be provided entirely or partially.

The pattern layer etc. as the transfer layer 3 may be made of, for example, acrylic,
Vinyl chloride-vinyl acetate, aminoalkyd, cellulose, etc. inks are used.

In forming the pattern layer, etc., printing methods such as gravure printing, silk screen printing, and offset printing are employed.

The metal vapor deposition layer as the transfer layer 3 is formed using a metal such as aluminum, chromium, or nickel by a vacuum thin deposition method, a sputtering method, or the like. When providing this metal vapor deposition layer, it is particularly desirable to provide the anchor layer first and then form it on the layer.

The heat-sensitive adhesive layer 4 is formed of a heat-sensitive adhesive that has adhesive properties to the molding material constituting the injection molded product, and examples of the heat-sensitive adhesive include acrylic, polyolefin, chlorinated polyolefin, rubber-based, polyvinyl chloride, Examples include those made of resins such as vinyl chloride/vinyl acetate copolymer and ethylene/vinyl alcohol copolymer. The adhesive layer can be coated using coating methods such as gravure coating, roll coating, gravure printing,
It can be formed by a printing method such as silk screen printing.

The heat-resistant layer 5 is provided between the base film 2 and the heat-sensitive adhesive layer 4, that is, between the release layer 6 and the transfer layer 3, between the transfer layer 3 and the adhesive layer 4, etc. at least in the injection mold. Gate part 7 (
(Fig. 2). In particular, it is preferable to provide it on the heat-sensitive adhesive 4 side as shown in FIG. The heat-resistant layer 5 is usually provided in a pattern at the above-mentioned predetermined locations, and in this case, the outline of the N5 is formed by so-called blur printing in which the amount of coating decreases continuously from the center to the periphery. , the heat-resistant layer 5 and the part where the cough N5 is not formed are in a state where it is difficult to distinguish. In addition, it is preferable that the heat-resistant layer 5 is not provided at a position corresponding to a region with high forming drawability in order to prevent microcracks that may occur in the transfer layer etc. due to the presence of the heat-resistant layer 5. It is not provided at a position corresponding to the corner portion 8 (Fig. 2) of the product.

As the material of the heat-resistant layer 5, a resin material having excellent heat resistance can be used, and for example, a resin material containing urethane type, acrylic urethane type, nitrocellulose, polyester, etc. as a main component can be used.

Further examples include ionizing radiation-curable resins, polysiloxanes, and the like. Among them, thermoplastic vehicles (e.g., urethane resins) that have been added with isocyanate to provide heat resistance.
In this case, the amount of isocyanate added is preferably 1 to 15 wt% based on the thermoplastic vehicle. If the amount added is less than 1 wt%, the heat resistance as a heat-resistant layer will be insufficient, and on the contrary, if it exceeds 15 wt%. This may cause poor adhesion between the layer and the layer it comes into contact with. Examples of the isocyanate include tolylene diisocyanate, metaxylene diisocyanate, coxamethylene diisocyanate, isophorone diisocyanate, and the like. As the ionizing radiation curable resin, urethane acrylate resin, polyester acrylate resin, melamine acrylate resin, etc. can be used.

The heat-resistant layer 5 can be formed by printing using the above-mentioned resin material by a known printing method, and the thickness of the heat-resistant layer 5 is 0.
5 to 2 μm is preferable.

When performing transfer using the transfer foil 1 of the present invention having the above-described configuration, first the transfer foil 1 is placed in an injection mold 9 with the base film 2 side facing the cavity surface, as shown in FIG. Next, based on the procedure of the known injection molding method, molten resin 10 as a molding material is injected and filled from the gate part 7 of the mold 9, and the resin is solidified or hardened to perform molding. , the injection molded product 11 is taken out from the mold, and the base film 2 is peeled off and removed. Through the above steps, the transfer N3 and the like are transferred to the surface of the injection molded product 11.

According to the transfer foil of the present invention, since the heat-resistant layer is always present at the position corresponding to the gate portion 9, it is possible to prevent ink from flowing when molten resin is injected from the gate portion 9.

The molding material for injection molded products to which the transfer foil of the present invention can be applied is not particularly limited as long as it is conventionally used for injection molding.

Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example 1 Polyethylene terephthalate film (manufactured by Toshi: 'r-
6o, #25) is coated with melamine resin (Showa Inks) to form a release layer, and then an ink made of acrylic resin (Showa Inks) is printed using the gravure printing method to create a pattern. After forming the layer, a heat-resistant layer is formed by printing a paint (Showa Ink) made of curable polyurethane containing 5 wt% isocyanate at a position corresponding to the gate part of the injection mold using a gravure printing method. Then, a heat-sensitive adhesive made of acrylic resin (Showa Ink) was applied to the surface to form an adhesive layer, and then cured at 40°C for 3 days to fully cure the heat-resistant layer.
It was made into an in-mold transfer foil.

Place this transfer foil in the injection mold as specified so that the heat-resistant layer corresponds to the gate position), then melt the AB.
After injection filling with S resin and molding, we removed the mold, peeled off the film, and performed transfer. As a result, a beautiful pattern layer with no ink flow was transferred to the injection molded product. did it.

Example 2 A heat-resistant layer was formed by gravure printing using a polyester acrylate-based ultraviolet curable resin (manufactured by Dainichiseika Chemical Co., Ltd.: PHC), with a thin coat around the gate area (corresponding to the mold edge area). ), output 160w
An in-mold transfer foil was prepared in the same manner as in Example 1, except that it was cured using a 7 cm high-pressure mercury lamp for 2 seconds.

When transfer was carried out in the same manner as in Example 1 using the obtained transfer foil, it was possible to transfer a beautiful pattern layer to the injection molded product without causing ink flow.

〔Effect of the invention〕

As explained above, the in-mold transfer foil of the present invention is constructed by providing a heat-resistant layer between the base film and the heat-sensitive adhesive layer at least at a position corresponding to the gate part of the injection mold. If ink flow occurs due to the molten resin injected from the gate part during injection molding, it will be reliably eliminated, and as a result, the desired transfer layer etc. can be transferred to the injection molded product without any problems caused by ink flow. can.

In addition, by forming the outline of the heat-resistant layer by blur printing, the boundary between the heat-resistant layer and the portion without the core layer is blurred, and the presence of the heat-resistant layer does not cause deterioration in design, etc. By configuring the above-mentioned heat-resistant layer so that it is not provided at a position corresponding to a location where molding drawability is large, such as a corner portion of an injection molded product, there is no possibility that the heat-resistant layer will cause problems such as cracks and molding defects. . Further, by forming the heat-resistant layer using a thermoplastic vehicle to which an isocyanate is appropriately added, there are advantages such as an increase in solvent resistance (chemical resistance).

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of the in-mold transfer foil of the present invention, and FIGS. 2 and 3 are cross-sectional views of essential parts showing an example of the process of transferring to an injection molded product using the transfer foil of the present invention. . l... In-mold transfer foil 2... Base film 3... Transfer layer 4,... Heat sensitive adhesive N 5... Heat resistant layer 7... Gate portion 8... Corner portion 9. ... Molten resin 11 ... Injection molded product 10 ... Molten resin

Claims (4)

[Claims] (1) A transfer foil formed by sequentially laminating at least a transfer layer and a heat-sensitive adhesive layer on a base film, which is placed in an injection mold and filled with molten resin by injection from the heat-sensitive adhesive layer side. In the in-mold transfer foil in which the transfer layer is transferred to the surface of the injection molded product, a heat-resistant layer is provided between the base film and the heat-sensitive adhesive layer at least at a position corresponding to the gate part of the injection mold. An in-mold transfer foil characterized by: (2) The in-mold transfer foil according to claim 1, wherein the outline of the heat-resistant layer is formed by blur printing. (3) Claim 1 or 2 in which the heat-resistant layer is not provided at a position corresponding to a corner portion of the injection molded product where drawability is required.
In-mold transfer foil as described. (4) Claims 1 to 3 in which the heat-resistant layer is formed from a thermoplastic vehicle to which isocyanate is added to impart heat resistance.
The in-mold transfer foil described in any of the above.