JPH06155518A - Manufacture of molded product possessing protective layer - Google Patents

Abstract

PURPOSE:To provide a manufacture of an improved molded product to form a protective layer whose surface physical properties are superior in wear resistance, scuffing resistance and solvent resistance on the molded product having a three-dimensional form. CONSTITUTION:After a transfer sheet which is obtained by applying ionization radiation curing resin of a thermoplastic solid under an uncured state to the upper part of a base film 11 having favorable moldability and furthermore printing 13 of a pattern and application of an adhesive agent 14 are performed is arranged within an injection mold and vacuum or vacuum air-pressure forming of the transfer sheet is performed by making use of a female mold 2A, a protective layer 12B is formed by solidifying the resin by applying ionization radiation to the transfer sheet. Then the title method is made into such constitution that the female mold 2A and a male mold 2B are clamped, the molten resin is injected through an injection nozzle 2C, injection molding is performed and a molded product 26 and the protective layer 12B are stuck to each other within a mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for producing a synthetic resin molded article having a protective layer on its surface.

[0002]

2. Description of the Related Art Conventionally, as a manufacturing technique for forming a protective layer on the surface of a synthetic resin molded product, after obtaining a molded product by injection molding or the like, a curable resin is applied to the surface of the molded product to cure the molded product. There is a way. This method can be performed manually without requiring special equipment, but in that case, the labor cost is high, and at the same time, the working environment for application becomes a problem. Next, there is a method of using a transfer sheet in which a protective layer of a curable resin is provided on a base film and transferring the protective layer onto the surface of a molded product. This method has a drawback that it cannot be transferred when the molded product has a three-dimensional shape, particularly a deep-drawn shape.

Further, a transfer sheet using a thermoplastic resin is used as a protective layer provided on the base film, and the transfer sheet is preformed as required, and the obtained preformed product is placed in an injection molding die. There is also a method of arranging and performing injection molding of synthetic resin to obtain a molded article having a protective layer. However, if the protective layer is a thermoplastic resin, it is generally impossible to improve surface properties such as abrasion resistance, scratch resistance and solvent resistance of the molded product. If a thermosetting resin having a surface property higher than that of a thermoplastic resin is used, cracks will occur during preforming.

Further, Japanese Examined Patent Publication No. 4-19924 and Japanese Patent Laid-Open No. 6-196024.
As disclosed in JP-A-3-132095, JP-A-1-176531, etc., an uncured resin is applied onto a moldable base film to prepare a transfer sheet, and this sheet is injection-molded. There is a method of providing a protective layer by irradiating a molded product with an ionizing irradiation ray to cure the resin after the resin is placed in a mold and injection molded. However, in this method, injection molding is performed in a state where the ionizing radiation-curable resin is uncured, so that the ionizing radiation-curable resin still has fluidity, and ink flows near the gate during injection molding. Further, when painting is performed by the transfer method, the base material sheet and the injection resin are heat-sealed by the high temperature and high pressure during injection molding.

[0005]

As described above, the method of obtaining a molded product by injection molding or the like and then applying a curable resin to the surface of the molded product to cure the molded product does not require special equipment. Although it can be done manually, the work efficiency is low, the labor cost is high, and at the same time, the work environment such as a solvent exhaust facility becomes a problem when applying. The method of using a transfer sheet with a protective layer of curable resin on the base film and transferring this protective layer to the surface of the molded product cannot be transferred if the molded product has a three-dimensional shape, especially a deep-drawn shape. There are drawbacks.

Next, a transfer sheet using a thermoplastic resin as a protective layer provided on the substrate film is used, and if necessary, this is preformed, and the obtained preformed product is placed in an injection molding die. Also, the method of injection molding synthetic resin to obtain a molded article having a protective layer is generally the case that when the protective layer is a thermoplastic resin, surface physical properties such as abrasion resistance, scratch resistance and solvent resistance of the molded article are generally observed. Can not be raised. When a thermosetting resin that gives higher surface properties than a thermoplastic resin is used, there is a drawback that cracking occurs during preforming.

Further, an uncured resin is applied onto a moldable base film to prepare a transfer sheet, which is placed in an injection molding die and injection molding is carried out. The method of irradiating the resin with ionizing radiation to cure the resin to form the protective layer is because injection molding is performed with the ionizing radiation-curable resin in an uncured state. Ink flow occurs near the gate during molding. Further, when painting is performed by the transfer method, there is a problem that the base material sheet and the resin are thermally fused due to high temperature and high pressure during injection molding.

In order to solve the above problems, the present invention provides a molded product having a three-dimensional shape, particularly a deep-drawn shape,
It is an object of the present invention to provide a method for producing a molded article having a protective layer having excellent surface physical properties such as abrasion resistance, scratch resistance and solvent resistance.

[0009]

[MEANS FOR SOLVING THE PROBLEMS] A transfer sheet having a protective film made of an ionizing radiation curable resin, which is a thermoplastic solid in an uncured state, is formed on a base film having good moldability by injection molding. After the transfer sheet is placed in the mold and vacuum-formed or vacuum / pneumatic-formed, it is irradiated with ionizing radiation to cure the resin and form a protective layer, and then the mold is closed and the molten resin is injected. Injection molding was performed to form a protective layer with high hardness inside the mold.

Further, a transfer sheet having a protective layer made of an ionizing radiation curable resin, which is a thermoplastic solid in an uncured state, on a base film having a good moldability is preliminarily adapted to an injection molding die. After vacuum forming or vacuum / pressure forming as described above, place the molded product in the injection mold,
Ionizing radiation is applied to cure the resin to form a protective layer, the mold is closed, the molten resin is injected, and injection molding is performed.
A method of forming a protective layer having high hardness in the mold was adopted.

[0011]

According to the present invention, a transfer sheet coated with a protective layer is preformed by an injection molding die, and the curable resin is cured by irradiating with ionizing radiation in the same die. It is possible to obtain an injection-molded article having no flow and a protective layer having high hardness in one step. The protective layer cured by irradiation with ionizing radiation has excellent surface properties such as abrasion resistance, scratch resistance, and solvent resistance, and a high quality molded product can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments with reference to the drawings. 1 to 5 are views showing a first embodiment. 50 μm of a transparent and moldable polyethylene terephthalate film (hereinafter referred to as PET film) is roll-coated with a solvent-dilutable UV-curable resin “Yupimer” manufactured by Mitsubishi Yuka Fine Co., Ltd. 10 to dry
A 15 μm coating film was obtained. Next, using a vinyl chloride / vinyl acetate copolymer ink, pattern printing was performed by a gravure printing method such that ultraviolet rays (hereinafter referred to as UV) were transmitted. Further, an adhesive layer was provided by gravure coating using an acrylic resin adhesive to prepare a transfer sheet as shown in FIG. The transfer sheet is arranged as shown in FIG. 2, the sheet is softened by heating the heating platen, compressed air is applied from the heating platen side, and vacuum molding is performed from the female side of the injection molding die to form a vacuum of the sheet on the cavity wall shape.・ Pressure molding was performed to obtain preforms. (Fig. 3) Next, UV irradiation is performed while sliding the preformed product with a slidable irradiation device equipped with an ultraviolet lamp (a high pressure mercury lamp with ozone having an output of 80 W / cm) as shown in Fig. 4. Then, the curable resin in the mold was cured to form a protective layer. Further, as shown in FIG. 5, the injection molding die is closed and the molten resin is injected by a conventional method to bond the injection-molded product and the protective layer to form the protective layer on the molded product.
The mold was opened, the molded product was taken out, and the PET film was peeled off to obtain a molded product having a protective layer on the surface. (Fig. 6)

Next, the second embodiment will be described. Using solvent-diluted electron beam curable resin, PE was prepared in the same manner as in Example 1.
The T film was roll-coated on 50 μm, printed with a pattern and coated with an adhesive to obtain a transfer sheet. (FIG. 7) This transfer sheet was vacuum-compressed and pressure-molded in a mold in the same manner as in Example 1 to prepare a preform of the protective layer.
Next, as shown in FIG. 8, an electron beam was irradiated by an electron beam irradiation device to cure the curable resin to form a protective layer. Further, the injection molding die was closed and the molten resin was injected in the same manner as in the first embodiment to produce a molded article having a protective layer.

In the third embodiment, first, a transfer sheet is made of PET film as in the second embodiment. Next, the transfer sheet is vacuum / pressure-formed in a separate step so as to be compatible with the injection molding die, and a preform is produced. An object obtained by irradiating this with an electron beam to cure the curable resin is placed in an injection molding die, and the injection molding die is closed to inject a molten resin in the same manner as in the second embodiment. Then, a molded product having a protective layer was produced.

[0015]

EFFECTS OF THE INVENTION According to the method for producing a molded article having a protective layer of the present invention, abrasion resistance, scratch resistance, solvent resistance, etc. can be obtained even if it has an arbitrary three-dimensional shape such as a deep drawing shape. It is possible to obtain a synthetic resin molded article having a protective layer having excellent surface physical properties.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a transfer sheet having moldability.

[Fig. 2] Diagram showing a transfer sheet placed between a mold and a heating plate for vacuum / pressure forming.

[Fig. 3] A state diagram of the transfer sheet subjected to vacuum / pressure molding.

FIG. 4 is a process diagram of forming a protective layer by irradiating ultraviolet rays to cure the resin

[Fig. 5] Process drawing for integrating the protective layer and the molded product by injection molding

FIG. 6 Molded product having protective layer

FIG. 7 is a sectional view showing the structure of a transfer sheet for electron beam curing.

FIG. 8 is a process diagram of forming a protective layer by irradiating an electron beam to cure the resin

[Explanation of symbols]

1A Transfer sheet having moldability (for UV curing) 1B Transfer sheet having moldability (for electron beam curing) 11 Base film (PET film, etc.) 12A UV curable thermoplastic resin layer 12B UV cured protective layer 13 Design Printing 14 Adhesive layer 2A Injection mold female mold 2B Injection mold male mold 2C Injection nozzle 21 Porous electroformed product 22 Exhaust hole 23 Hot plate device also serving as ventilation line 24 Vent hole 25 Vacuum / Compressed air source connection pipe 26 Injection molding resin (polystyrene, polypropylene, etc.) 27 Molded product with protective layer 41 UV lamp housing 42 UV lamp reflector 43 UV lamp 44 Shutter 45 Sliding UV lamp supporting device 71 Electron beam curable thermoplastic resin Layer 81 Electron beam irradiation device

Claims (2)

[Claims] 1. A transfer sheet provided with a protective layer made of an ionizing radiation curable resin, which is a thermoplastic solid in an uncured state, on a base film having a good moldability, is placed in an injection molding die. Then, after vacuum forming or vacuum / pneumatic forming of the transfer sheet, it is irradiated with ionizing radiation to cure the resin to form a protective layer, and then the mold is closed and the molten resin is injected to perform injection molding. A method for producing a molded article, which comprises performing a protective layer having high hardness in a mold. 2. A transfer sheet in which a protective layer made of an ionizing radiation-curable resin, which is a thermoplastic solid in an uncured state, is provided on a base film having a good moldability, which is adapted in advance to an injection molding die. After vacuum molding or vacuum / pneumatic molding, place the molded product in the injection molding die and irradiate it with ionizing radiation to cure the resin and form a protective layer, then close the mold and melt. A method for producing a molded article, which comprises injecting a resin and performing injection molding to form a protective layer having high hardness in a mold.