JPS5935775B2 - Method for manufacturing synthetic resin decorative body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for industrially manufacturing a synthetic resin decorative body made entirely of a transparent material and having only a printed layer encapsulated therein.

Synthetic resin decorations with artificial flowers or the like sealed inside have been widely known.

A common method for producing these decorations is to inject liquid resin into a container filled with artificial flowers, etc., and perform casting polymerization.

However, this method requires a long time for polymerization, bubbles are likely to occur during injection, requires a high level of skill, and is therefore expensive.

In addition, when using cast polymerization, it is difficult to encapsulate printed characters inside, and even if printed paper is encapsulated, the paper can be seen through from the outside, making it unnatural. Even if it looks normal, there is a drawback that it cannot be seen on the other side, and I regret that it is not a good method.

Furthermore, a so-called encapsulation molding method is known in which decorated paper, film, etc. is encapsulated inside a molded product by injection molding, but because the inclusions such as paper or film are inside, the display cannot be clearly seen It may not be possible to see through
In addition, to solve this problem, cutting the inclusions themselves into unique or complicated shapes requires extremely troublesome work, and it is difficult to place such inclusions in precise positions during the first molding stage. Loading is difficult and significantly reduces production efficiency, and there is also a concern that the inserted material may be misaligned due to the pressure during injection molding, or the displayed pattern may be distorted.

The present invention has been made in view of the above circumstances, and its gist is as follows: (A) A method for manufacturing a synthetic resin decorative body characterized by comprising the following steps: (A) Decoration A primary molded product constituting a part of the body is molded by injection molding of a transparent thermoplastic resin so that the encapsulating surface is flat. (B) After the primary molded product is taken out of the mold, the encapsulating surface is Perform desired printing with thermosetting resin ink. (Q) Load the primary molded product printed as described above into a mold for forming a decoration with the printed surface facing the mold space. Next, a transparent thermoplastic resin is injected into the mold for molding the decorative body to form the decorative body.

It is in.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIGS. 1a to 1e are cross-sectional views schematically showing each step of the present invention.

First, the present invention begins by molding a primary molded product constituting a part of a decorative body by injection molding of a transparent thermoplastic resin (Step A).

That is, as shown in FIG. 1a, the primary molded product 11 is placed in the mold 2.
injection molding using

The shape of this primary molded product 11 is approximately the same as the finished decorative body 1 cut in half.

However, it is not necessarily limited to half-cut shapes.

However, since printing is applied to the enclosing surface 11a in post-processing, the enclosing surface 11a needs to be flat.

The thermoplastic resin used for molding the primary molded product 11 includes methacrylic resin, styrene resin, and the like.

Polycarbonate resin, styrene-acrylonitrile resin, etc. are not particularly limited, but methacrylic resin, which has excellent transparency and weather resistance, is most suitable.

Furthermore, these resins are usually colorless and transparent, but colored and transparent materials may also be used.

Next, after the next molded product 11 is taken out from the mold 2, desired printing is applied to the enclosing surface 11a using thermosetting resin ink (Step B).

For printing at this time, it is necessary to use thermosetting resin ink.

In this case, if the product is printed using thermoplastic resin ink, the printing will be damaged by injection molding in the subsequent process, making it impossible to obtain a finished product.

The printing method in this step may be a normal printing method such as screen printing.

However, if the printed surface 3 is to be viewed from both sides of the decoration, it is desirable to print it twice or more so that the characters can be seen normally from both sides.

However, if the printing layer on the printing surface 3 is extremely thick, it may be distorted by the flow of molten resin during injection molding, so care must be taken.

The cross section of this printed primary molded product 11 is shown in the first figure.
It is a diagram.

The primary molded product printed as described above has its printed surface 3
is loaded into a mold 4 for molding a decorative body toward the mold space (step C).

That is, as shown in FIG. 1C, the primary molded product 11 is loaded into the cavity of the mold 4 for molding the decorative body so that the printed surface 3 faces the space.

This loading operation is a preparatory step for the next injection molding, and the precision of the mold 4 must be improved so that the primary molded product 11 can fit in a tight state.

Note that vacuum pressure may be used to suck the primary molded product 11 into one side of the mold 4 in a stable manner.

Next, a transparent thermoplastic resin is injected into the mold 4 for molding the decorative body to form the decorative body 1 (Step D).

Figure 1d shows the injection molded state, and 12 indicates the transparent thermoplastic resin injected in this step.

The transparent thermoplastic resin in this case is no different from the transparent thermoplastic resin in step (A) above, and is usually (
The same type of resin as in step A) is used.

Note that the thermoplastic resin in this case is generally a colorless and transparent material as in step (A), but a colored and transparent material may also be used.

The injection molding in this step is no different from the usual method, but better results can be obtained by lowering the injection pressure somewhat.

After the molding is completed as described above, the decorative body 1 is taken out from the mold 4 as shown in FIG. 1e, and post-processing is performed as necessary (Step E).

The decorative body 1 is naturally taken out after the molded product has cooled to a certain temperature, but it is preferable to increase the precision of the mold 4 as much as possible so that the finished product can be obtained immediately after being taken out.

Note that the post-processing mentioned here refers to cutting, cutting, drilling, polishing, etc., which may be essential depending on the structure of the decorative body 1.

Specific examples will be described below.

A decorative body for a key chain as shown in FIG. 1e was manufactured using methacrylic resin.

Acryvet MD (transparent) manufactured by Mitsubishi Rayon Co., Ltd. was used as the methacrylic resin, and a primary molded product as shown in Figure 1 was first injection molded using a V-15-75 injection molding machine manufactured by Nippon Steel.

Next, 5S- manufactured by Toyo Ink was applied to the encapsulating surface of this primary molded product.
Screen printing was performed using 25000 series thermosetting resin ink, and baking was performed at 80° C. for 30 minutes.

The primary molded product obtained in this way is loaded into a decoration molding mold with its printed surface facing the mold space as shown in Fig. 1C, and then injection molded again using the same AcryPeller MD as above. Then, a decorative body as shown in Fig. 1e was manufactured.

The obtained decorative body was beautiful, with only the printed layer encapsulated in a transparent material, and was in good condition with no deterioration of the printing.

For comparison, the enclosing surface of the above-mentioned next molded product was printed using Toyo Ink Co., Ltd.'s 5S-85000 series thermoplastic resin ink, and the same as above was loaded into a decorative body mold and injection molded. When this process was carried out, the printed layer located on the encapsulating surface collapsed, and the product could not be used at all.

Since the present invention is constructed as described above,
It is possible to easily produce a beautiful decorative body made entirely of transparent material and with only the desired printed layer encapsulated inside.In particular, since the printed layer is printed with thermosetting resin ink, it will not discolor during injection molding. Moreover, since only the printing layer is encapsulated without using any paper or film, it can be seen clearly from both sides and the decorative body is strong, compared to conventional cast polymerization. It has advantages such as being economically superior.

[Brief explanation of the drawing]

Figures 1a to 1e are cross-sectional views schematically showing steps A to Q of the method of the present invention. 1... Decorative body, 11... Primary molded product,
11a...Inclusion surface of primary molded product, 2...
・Mold (of the primary molded product), 3... Printing surface, 4.
...Mold for molding decorations.

Claims (1)

[Scope of Claims] 1. A method for producing a synthetic resin decorative body, characterized by comprising the following steps (A) to (g). (B) After taking out the next molded product from the mold, the desired printing is performed on the encapsulating surface using thermoplastic resin ink. (Q. The printed primary molded product is loaded into a mold for forming a decorative body with its printed surface facing the mold space. The decorative body is molded by injecting resin. After molding is complete, the decorative body is removed from the mold and subjected to post-processing as necessary.