JPH0261370B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing synthetic resin articles such as compact containers for containing cosmetics.

For compact containers made of synthetic resin, it is important for them to have excellent design and decoration, so the surface of the lid of the compact container can be decorated with various metallic patterns, for example. It is common to add letters, designs, etc.

By the way, compact containers like this one,
Usually, it is manufactured by injection molding, but in order to add color rendering properties to the metallic patterns, letters, and designs mentioned above for the purpose of further enhancing decorativeness, a separate process is required after injection molding. In other words, it is necessary to use methods such as vapor deposition, printing, or transfer for decoration, which increases the number of man-hours and increases costs.

The present invention was made in view of the above circumstances, and
Injection molding is performed using a mold that has patterns such as letters and designs formed on its surface, and fine grid lines are formed either on the patterned portion or other portions excluding the patterned portion. Therefore, by transferring patterns such as letters and designs including the grid line portion of the mold to the injection molded product, patterns such as letters and designs can be simultaneously formed when injection molding a lid of a compact container, etc. What's more, the transferred grid lines are split into the visible light spectrum by light diffraction, creating an iris glow, and when contrasted with areas without grid lines, patterns such as letters and designs stand out even more as decorations. The object of the present invention is to provide a method for manufacturing a synthetic resin article that can form a surface.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The embodiment shown in the figure shows an example in which the technology according to the present invention is applied to a compact container. In FIGS. This pattern 2' has a large number of evenly spaced parallel grid lines (more than 500 in 1 mm) 3'. These many grating lines 3' form a so-called diffraction grating that diffracts white light to produce a series of visible light spectra with iris brightness and a certain spread.

Next, a method of manufacturing the lid body 1 having the pattern 2' including the grid lines 3' will be described.

First, as shown in FIG. 4, on one surface forming a cavity in the synthetic resin injection mold for molding the lid body 1, that is, on the surface 4a of the upper mold 4 in the illustrated example, Similar to the pattern 2', a pattern 2 consisting of a large number of grid lines 3
Form it.

As shown in FIG. 3a, for example, the pattern 2 can be formed by forming a large number (more than 500 pieces per 1 mm) of diamonds or the like with a special shape on the surface of the mold 4 at equal intervals and parallel to each other. Grid lines (grooves)
3..., and then, as shown in Figure 3b, after removing the grid lines 3 from other parts by a well-known method such as corrosion machining so that only the desired pattern 2 remains, this removed By surface finishing the portion, the desired pattern 2 is formed.

After forming the desired pattern 2 in this way, use a mold having this pattern 2,
When injection molded with transparent, colorless or lightly colored synthetic resins with relatively low shrinkage rates, such as PET, PMMA, PC, SAN, and PS, the injection molded products
That is, the pattern 2 of the upper mold 4 is faithfully transferred to the surface 1a of the lid body 1, and the lid body 1 having the pattern 2' consisting of a large number of grid lines 3' shown in FIG. 1 is obtained. As described above, this pattern 2' of the lid body 1 diffracts white light by its many lattice lines 3', and appears on the surface as an iris-patterned visible light spectrum. It exhibits the decorative effect of 1a.

Incidentally, in the above embodiment, the grid lines 3' are formed only in the pattern 2' portion, but when forming the pattern 2 on the mold, only the pattern 2 portion is subjected to the corrosion described above. If injection molding is carried out in the same manner using a mold that has been removed by a processing method or the like, it is possible to obtain a lid body having a so-called reverse contrast pattern in which only the pattern 2' portion does not diffract light.

Further, if the pattern 2 is formed on the lower mold 5, the pattern 2' can be formed on the back side of the lid body 1. In this case, if the resin forming the lid body 1 is transparent, this pattern 2' can naturally be seen from the front side of the lid body 1.

Note that the present invention is not limited to compact containers as in the embodiments, but can also be applied to injection molded products where decorativeness is important, such as synthetic resin container bodies and lids for storing milky lotions, creams, etc. Needless to say, it is applicable. Further, the pattern 2' may be formed into a spherical shape as a whole using a mold, and the grid lines 3... are not limited to linear shapes as in the illustrated example, but can be formed as a whole in a planar view. It may be formed so that a portion thereof is curved.

Further, if A or the like is vapor-deposited on this pattern 2' or on the surface opposite to the surface on which this pattern 2' is formed, a visible light spectrum with even more iris brilliance can be obtained.

As described in detail above, the present invention has characters on the surface,
Injection molding is performed using a mold in which a pattern such as a design is formed and fine grid lines are formed either in the pattern part or other parts excluding only the pattern part, and by this injection molding. Since patterns such as letters and designs including the grid line portion of the mold are transferred to the injection molded product, patterns such as letters and designs can be simultaneously formed when injection molding a lid of a compact container, etc. What's more, these are optically colored, that is, due to the well-known principle of diffraction gratings, they appear on the surface as a brilliant spectrum, such as an iris pattern, which has the effect of forming an excellent decorative surface. . As described in detail above, the present invention has a pattern such as letters or designs formed on the surface, and fine grating lines forming a diffraction grating are formed on either the pattern portion or other portions excluding the pattern portion. A synthetic resin with a relatively low shrinkage rate is injection molded using a mold, and patterns such as letters and designs, including the grid line portion of the mold, are transferred to the injection molded product through this injection molding. Because of this, when injection molding compact container lids, etc., patterns such as letters and designs can be faithfully transferred and formed at the same time, and these patterns are based on the principle of diffraction gratings, which are formed by fine grid lines. It is optically colored and appears on the surface as a bright spectrum such as an iris pattern, which has the effect of forming an excellent decorative surface. In addition, in this case, as a resin for forming the injection molded product,
Colorless or lightly colored transparent resin is used.
Moreover, since metal such as aluminum is vapor-deposited on the patterned surface or the opposite surface,
When the injection molded product itself is relatively thin, such as the lid of a compact container, the decorative effect of the decorative surface appears on both the front and back sides of the injection molded product. Not only are the front and back surfaces different in color, but both surfaces constitute decorative surfaces in the form of a rainbow spectrum that rotates depending on the viewing angle, like the surface of a so-called luminous disk.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention. Figure 1 is a plan view of a compact container (lid), Figure 2 is a sectional view taken along the - line in Figure 1, and Figures 3 a and b are molds. FIG. 4 is a schematic sectional view of a mold shown for explaining the manufacturing method of the present invention. 1... Lid body, 1a... Surface, 2, 2'... Pattern, 3, 3'... Grid line, 4... Upper mold, 4
a...Surface.

Claims (1)

[Claims] 1 A pattern 2 such as letters or designs is formed on the surface, and fine grating lines 3 forming 500 or more diffraction gratings in 1 mm are formed either on this pattern part or other parts excluding the pattern part. A colorless or lightly colored transparent synthetic resin with a relatively low shrinkage rate is injection molded using a mold 4, and by this injection molding, patterns such as letters, designs, etc., including the lattice line portion of the mold 4 are formed. is transferred onto an injection molded product 1, and then a metal such as aluminum is vapor-deposited on the surface on which the pattern is formed or the surface opposite to the surface on which the pattern 2 is formed. manufacturing method.