JPH0890594A - In-mold decorating of thermoplastic resin molded product - Google Patents

Abstract

PURPOSE: To provide an in-mold decorating method capable of easily obtaining a molded product having sufficient surface physical properties even if post- painting is not applied. CONSTITUTION: After a printed plastic film 13 is set to a mold cavity 15, a molding material composed of a thermoplastic resin is injected in the mold cavity 15 to perform in-mold decorating. As the printed plastic film 13, one of which the printed surface protecting layer 21 is formed from a prepolymer or semicured resin having shape followability is used. After a molded product is demolded, the prepolymer or semicured resin forming the printed surface protecting layer 21 is perfectly cured (polymerized).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a printed plastic film (hereinafter sometimes simply referred to as "printing film") in a mold cavity and a molding material made of a thermoplastic resin in the mold cavity. The present invention relates to a method of performing injection molding and so-called in-mold molding. In particular, interior and exterior parts for automobiles that require abrasion resistance, scratch resistance, surface heat resistance, weather resistance, light resistance, chipping resistance, etc., such as center cluster panels, console upper panels, wheel caps, pillar garnishes. The invention is suitable for outerwear and the like.

[0002]

2. Description of the Related Art Conventionally, as a method of giving a woodgrain pattern to a center cluster panel 11 having a three-dimensional shape as shown in FIG.

[0003]

However, in the case of a three-dimensional molded product which requires deep drawing, such as a lid for a console box, it is a soft and thin-walled print film having shape conformability. Is required. Therefore, the molded product obtained by the above-mentioned painting molding generally has a problem that surface properties such as abrasion resistance, scratch resistance, surface heat resistance, weather resistance, light resistance, and chipping resistance are not sufficient. Therefore, usually, the molded product after release from the mold is post-coated to impart these physical properties. However, the number of man-hours required for coating after this is significantly increased.

From the viewpoint of ensuring the conformability to the mold cavity surface, the printed film tends to be thin in order to make it easy to stretch particularly in the case of a molded product having small irregularities. The film may be torn or wrinkled at the sharp corners or deep drawing of the product, or the printed surface may be scratched. However, there is a problem that it is difficult to obtain a molded product with high productivity with good productivity.

In view of the above, it is an object of the present invention to provide a decorative molding method which can easily obtain a molded article having sufficient surface physical properties without post-coating.

Another object of the present invention is to tear or wrinkle the film at an acute angle portion or a deep drawing portion of the mold during molding.
Further, it is an object of the present invention to provide a decorative molding method capable of obtaining a highly designed molded product with good productivity, in which the printed surface is not easily scratched and the printing is not blurred at each convex portion of the molded product.

[0007]

The method of painting a thermoplastic resin molded article according to the present invention solves the above problems by the following constitution.

When the printing film is set in the mold cavity and then a molding material made of a thermoplastic resin is injected into the mold cavity to perform picture formation, as the printing film, the printing surface protection layer has a form-following property. A prepolymer or a semi-cured resin having the above is used, and the prepolymer or the semi-cured resin forming the printed surface protective layer is completely cured (polymerized) after the molded product is released from the mold.

[0009]

The method of the present invention will be described in detail below with reference to the drawings.

(1) It is a precondition that the printing film 13 is set in the mold cavity 15 and then the molding material 16 made of a thermoplastic resin is injected into the mold cavity 15 to perform the painting molding. (See Figure 4). In the illustrated example, 17 is a movable type (male type), and 19 is a fixed type (female type).

Here, as the thermoplastic resin, ABS resin, AS resin, polyethylene, polypropylene, polyacetal, thermoplastic urethane elastomer (TPU),
Polyamide, saturated polyester, PVC, polymethylmethacrylate (PMMA), saturated polyester (PB
T, PET, etc.), polyphenylene oxide (PP
O), polycarbonate (PC), other alloy resins (PC / ABS, PC / PBT, PBT / ABS, PP)
O / PA, etc.).

The mode of injection of the molding material into the cavity is
Usually, it is injection, but it may be transfer, compression, or blow.

The inner surface material of the printing film and the injection material (molded product body material) are usually selected so as to be heat-sealed by the heat of material at the time of injection. , Apply an adhesive treatment to the inner surface of the printing film.

(2) In the above structure, in this embodiment, the printing surface protective layer 2 is used as the printing film 13 (or 13A).
1 is formed of a prepolymer or semi-cured resin having shape following property.

Here, the printing surface protective layer 21 is formed of the prepolymer or the semi-cured resin, because the prepolymer or the semi-cured resin has a form following property (flexibility and stretchability).
It is possible to make the printing surface protection layer 21 located outside the printing surface 23 of the printing film 13 thicker as compared with the conventional one because of its excellent performance. The film may be torn or wrinkled at sharp corners or deep-drawn parts, the printed surface 23 may be damaged, and the relative elongation of the printed surface at the convex corners of the molded article can be reduced, which may lead to stretching. It is possible to avoid the print blurring caused by the above.

Specifically, as shown in FIG. 2 (1), a film (printing surface protection layer) 21 formed of a prepolymer or a semi-cured resin is directly printed 23, or FIG. 2 (2).
As shown in (1), it is possible to use a soft printing film 25 on the outer surface of which a printing surface protection layer 21 formed of a prepolymer or semi-cured resin having shape conformability is formed. Usually, a laminate film (release layer) 20 is used by being attached to the outer surface of a film (printing surface protection layer) formed of a semi-cured resin in order to prevent adhesion.
Here, as the printing substrate of the soft printing film 25, PM is used.
Examples include films of soft thermoplastic resins such as MA, PET, PVC and the like. Also, for thin printing paper and printing cloth,
A so-called prepreg prepared by impregnating a prepolymer or a semi-cured resin can also be used. Further, a soft thermoplastic film such as PET or PVC can be used as the laminate film.

The prepolymer is not particularly limited as long as it is a polymer that has been polymerized to such an extent that it can hold the printing surface, but in consideration of the fact that the molded product is usually a thermoplastic resin having little heat resistance, A photopolymerizable photosensitive resin is desirable. Specifically, polyester acrylate, epoxy acrylate, urethane acrylate,
An acrylic resin such as an acrylate of a polyhydric alcohol can be mentioned. In addition, these resins usually include
A photopolymerization initiator is added.

Examples of the photopolymerization initiator include benzoylalkyl ethers, acylphosphine oxides, oxime esters, bisimidazole, and the like.
The compounding amount with respect to 100 parts by weight of the prepolymer is 1 to
10 copies. Amines can be appropriately used in combination with these polymerization initiators as an accelerator.

The semi-cured resin is in an uncured state in which it has been cured to the extent that it can hold the printing surface. It is not particularly limited as long as it can be completely cured without substantially exerting a heat influence, and examples thereof include thermosetting resins such as melamine, urea resin, unsaturated polyester and the like.

Since the printing film of the present invention is superior to the conventional soft film in form following property,
0 to 100 μm), and generally 100 to 300 μm in total thickness.

(3) Although not essential, it is desirable to set the printing film 13 in the mold cavity after preforming.

This is because the pre-shaping increases the followability at the time of setting on the mold cavity surface having irregularities and prevents the printed surface from being broken due to abrupt deformation.

As a method of preforming, as shown in FIG. 3, a preforming die 27 is used to perform vacuum forming (vacuum drawing) and / or blow molding (compressed air blowing). To do. In the figure, 29 is a suction hole and 31 is a chuck.

(4) It is desirable to cut the printing film 13 by instantaneously raising the mold clamping pressure immediately before the mold releasing during the mold clamping of the picture-forming molding so that deburring can be eliminated. At this time, the outside of the mold PL surface with respect to the product portion is the relief portion 17a.
The burr cutting part 17b is formed (see FIG. 5). In addition, when deburring, the laminated film 2
It is desirable to leave 0 as shown in Fig. 5 (2) from the standpoint of workability for deburring and releasability.

(5) In this embodiment, the prepolymer or semi-cured resin forming the printing surface protection layer 21 is completely cured (polymerized) after the molded product is released (FIG. 6).

As the curing means, when a photosensitive resin is used as a prepolymer, an ultraviolet lamp 33 is usually used. However, infrared rays or other heating means may be used depending on the curing mode of the resin. Good. The curing time is usually 1 to 60 seconds in the case of an acrylic photosensitive resin, for example. The laminate film 20 may be removed before curing or after curing.

(6) The thus-prepared decorative molded product is
Since the printed surface is protected by the completely cured (polymerized) resin layer on the surface, it is possible to easily obtain a material having excellent surface physical properties such as abrasion resistance, scratch resistance, and surface heat resistance.

[0028]

As described above, in the method for painting a thermoplastic resin molded article according to the present invention, the printing surface protective layer is formed of a prepolymer or a semi-cured resin having a form following property as a printing film. The pre-polymer or semi-cured resin that forms the printing surface protective layer of the printing film after molding is completely cured (polymerized) after preforming the printing film and setting it in the mold cavity. Depending on the configuration, the following actions and effects are achieved.

Since a thick protective layer can be formed on the outer side of the printing surface of the printing film by a prepolymer or semi-cured resin having excellent conformability, the printing surface can be sufficiently formed from the acute angled portion of the mold surface during shaping. In addition to being protected, the elongation of the printing surface at the convex corners of the molded product can be made relatively small, and a decorative molded product with high designability can be obtained with good productivity. Also, by post-curing the molded product after release,
A molded product having sufficient surface properties can be easily obtained without painting.

Further, when the mold is clamped for painting, the clamping pressure is instantaneously increased immediately before the mold is released, so that the printing film can be cut and deburring is unnecessary.

[Brief description of drawings]

FIG. 1 is a perspective view of a console box that is an example of a decorative molded product to which the present invention is applied.

FIG. 2 is a cross-sectional view showing each example of a printing film used in the present invention.

FIG. 3 is a schematic cross-sectional view showing a preformed printing film.

FIG. 4 is a schematic cross-sectional view before printing film setting at the time of painting and forming the printing film.

5 is a cross-sectional view of each main part at the start of burr cutting and after burr cutting when the mold shown in FIG. 4 has a burr cutting structure.

FIG. 6 is a schematic cross-sectional view of a molded product after being released from the mold during ultraviolet curing.

[Explanation of symbols]

13, 13A Printed plastic film (printing film) 15 Mold cavity 20 Laminating film (release layer) 21 Printing surface protective layer 23 Printing surface

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Claims (3)

[Claims] 1. When a printed plastic film is set in a mold cavity, and a molding material made of a thermoplastic resin is injected into the mold cavity to perform picture formation, the printed plastic film is printed. Use a surface protective layer made of a prepolymer or semi-cured resin that has morphological conformability. After releasing the molded product, completely cure (polymerize) the prepolymer or semi-cured resin that forms the printed surface protective layer. A method for painting and molding a thermoplastic resin molded article, which comprises: 2. The painting method for a thermoplastic resin molded article according to claim 1, wherein the printed plastic film is pre-shaped and then set in the mold cavity. 3. The method for painting a thermoplastic resin molded article according to claim 1, wherein the prepolymer forming the printing substrate is a photosensitive resin.