JPS625775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and a molding apparatus for a synthetic resin molded product having a band-like color pattern. The purpose is to easily and reliably mold a molded product.

[Conventional technology]

Conventionally, there are many synthetic resin molded products in which a base body that forms the overall shape of the molded product and provides the background color of the molded product and a pattern piece that forms a band-shaped color pattern are combined together.

The molded product having this band-like color pattern may be molded using the molding apparatus disclosed in Japanese Patent Application Laid-Open No. 52-12267, or may be molded by molding the base body and the pattern piece separately, and forming the predetermined shape. In some cases, a molded product is completed by joining the molded base body and pattern piece with adhesive or ultrasonic bonding or the like to integrate them.

[Problems to be solved by the invention] What is disclosed in JP-A-52-12267 is
It has the advantage that the base body and the pattern piece can be sequentially molded using a single mold device, and that the base body and the pattern piece can be integrally joined at the same time as molding, but on the other hand, it has a slide core. Since it is a mold device, not only does the overall structure of the mold device become complicated, but also if the base body to be molded first has a divided structure, this divided base body The division form of this base body is specified so that it can be firmly and immovably held in the molding space, which limits the band-like color pattern form that can be produced, and also prevents the sliding movement of the slide core. As a result, a molding space for the pattern piece is formed, so the joint surface between the pattern piece to be molded and the base body is specified to the plane along the sliding direction of the slide core, and thus the connection between the base body and the pattern piece is In order to increase the bonding strength, it has not been possible to adopt a method of forming irregularities on the bonding surface, and for this reason, it has been impossible to increase the bonding strength between the base body and the pattern piece.

Conventional insert molding technology, including this Japanese Patent Application Laid-open No. 52-12267, involves insert molding in a mold for a pattern piece or base body that becomes a part of a mold for a base body or pattern piece that will be injection-molded later. If it is extremely difficult to assemble and maintain the pattern in a fixed manner, and the pattern piece or base body that is pre-positioned in the mold is a three-dimensional object with a certain height, depth, and width, and is an integral object. , although it is possible to implement it,
This is almost impossible when the pattern piece or base body pre-positioned in the mold is elongated, plate-shaped, or even consists of a plurality of separate objects.

If one of these is part of the mold and the other is injection molded to form an integrated product,
Since the pattern pieces and the base body were always integrally connected to each other on either the back surface, the end portion, or even the center portion of the molded product, the pattern pieces or the base body were never completely separated.

For this reason, if the pattern piece is made transparent, this connected part will appear as the appearance of the molded product, which will seriously impair the appearance of the molded product. It was not possible to make the pattern pieces transparent except to hide parts.

Furthermore, in cases where the base body and the pattern piece are molded separately and then joined together in a predetermined mutual positional relationship to form a molded product, the shape of the pattern piece can be set relatively freely. On the other hand, it has the advantage that injection molding operation is easy.
The work of joining the base body and pattern piece is troublesome, and gaps and steps may occur between the base body and pattern piece due to slight molding errors (including shrinkage during molding of the base body and pattern piece). Furthermore, since the pattern pieces are assembled by being fitted into recesses formed on the surface of the base body, it is difficult to obtain transparent color patterns, and the pattern is limited to opaque color patterns.

The problem with the conventional technology described above is that when insert molding is used, the retention state of the previously molded part in the mold is sufficient to support the injection pressure of the part to be injection molded later. endure,
inability to hold its position immovably;
If the molding space of the part to be molded later is divided by the part molded earlier, the same number of gates for the part to be molded later as the divided molding spaces are required. , and a temporal pressure difference occurs between the divided molding spaces, and this pressure difference causes an incorrect moving force to act on the previously molded part, and furthermore, the outside of the molded product. This is caused by the fact that when viewed from the surface side, a portion that was molded first and a portion that was molded later overlap.

The present invention has been devised to solve the problems and inconveniences of the conventional examples described above. The technical problem is to mold it into a structure that can be assembled and held in the mold, and to make sure that the inflow and filling speed of the material for molding the other part into the divided molding space for molding the other part is the same. It is something.

[Means and actions for solving problems]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to drawings showing one embodiment of the present invention.

The method for molding a synthetic resin molded product having a band-shaped color pattern according to the present invention includes dividing the base body 2 into a desired number of pattern pieces 30 of a desired color and disposing the base body 2 and pattern pieces 30 alternately, A method for molding a molded product 1 in which the upper surface, lower surface, and side end surfaces of the pattern piece 30 other than the end surface to be joined to the base body 2 are exposed to the outside, in which connecting pieces 32 are preliminarily attached to both end surfaces of the pattern piece 30.
The positioning piece 35 is integrally injection-molded through the mold, and the positioning piece 35 is fixed at a location outside the mold surface of the molds 4 and 5.
The pattern piece 30 is held at a predetermined position in the molding space via the connecting piece 32 by fixing it to the molds 4 and 5,
After the molds 4 and 5 are clamped, the base body 2 is injection molded through a dedicated gate 21 in each molding space divided by the pattern piece 30, and after the mold is released, the connecting piece 32 and the positioning piece 35 are The molded product 1 is molded by separating it from the pattern piece 30.

Further, a molding device for carrying out this molding method is integrally provided at a predetermined location outside the mold surface of one or both of the molds 4 and 5 on both side end surfaces of the pattern piece 30 via connecting pieces 32. A holding hole 50 is provided in which the positioning piece 35 is tightly fitted, a groove 51 is provided in one or both of the molds 4 and 5, and a groove 51 is provided in which the connecting piece 32 is tightly fitted. Each of the molding spaces divided by 30 is provided with a gate 21 having a flow passage cross-sectional area proportional to the volume of each molding space.

That is, in the method of the present invention, the side end surface of the pattern piece 30 that does not face the base body 2, that is, the molded product 1
A thin connecting piece 3 is attached to the side end surface forming a part of the side end surface of
The pattern body 3 is molded by integrally molding the positioning piece 35 via the mold 2, and by assembling the positioning piece 35 of the pattern body 3 to the molds 4 and 5, the pattern piece 30 is placed in the molding space. The injection molding of the base body 2 is achieved by assembling and holding the base body 2 immovably.

In addition, the molding device includes a positioning piece 35 integrally molded with the pattern piece 30 on the mold matching surfaces of the molds 4 and 5.
a holding hole 50 in which the connecting piece 3 is fixedly fitted into the holding hole 50;
Since a groove 51 is formed in which the pattern body 3 is fixedly fitted, the positioning piece 35 and the connecting piece 32 of the pattern body 3 are fixedly fitted and assembled into the holding hole 50 and the groove 51. The pattern piece 30 can be immovably positioned on the mold surface, and the gate 21 formed in each molding space divided by the pattern piece 30 has a flow passage cross-sectional area proportional to the volume of the corresponding molding space. This is set as
This is to ensure that the injection of molding material into each divided molding space is completed at the same time within the same injection time.If there is a large temporal variation in the completion of injection of molding material into each divided molding space, This is because not only is there a loss of molding time, but also there is a risk that the pattern piece 30, which has been carefully placed in a fixed position, may be deformed or displaced due to the injection pressure.

〔Example〕

The molded product 1 formed by the method and apparatus of the present invention has a band-like color pattern and is advantageous when used for products with a relatively large surface area, such as compacts and high-grade soap containers, as shown in FIG. As shown, the base body 2 presenting the ground color is divided by a desired number of pattern pieces 30 of a desired color, and each base body 2 and the pattern pieces 30
are arranged alternately in parallel.

That is, the base bodies 2 are completely separated from each other by the pattern pieces 30, and are integrally connected via the pattern pieces 30.

In this way, the pattern piece 30 is positioned across the molded product 1, but its planar shape is not particularly limited and can be appropriately set to a desired shape.

In addition, in the illustrated example, there are two pattern pieces 30, but you can use as many as you desire, and by setting the color of each pattern piece 30 to a different color, you can freely create a multicolor strip pattern. can be formed.

Furthermore, when each pattern piece 30 is colored and transparent, the entire part of this pattern piece 30 becomes transparent, and since there is no opaque part in this transparent part and this transparent part has a free shape, a pattern effect is produced. The value will be high.

Whether the pattern piece 30 is used as part of a mold and the base body 2 is injected to form the molded product 1, on the other hand, the base body 2 is used as part of the mold and the pattern piece 30 is injected to form the molded product. 1, base body 2
Since the pattern piece 30 and the pattern piece 30 will be welded together only between their opposing end faces, it goes without saying that the base body 2 and the pattern piece 30 must be molded with a molding material with excellent compatibility. In addition, as shown in FIG. 3, a protruding strip 30a (provided on the pattern strip 30 in the illustrated example) is provided along the longitudinal side on the welded end surface of the base body 2 or the pattern strip 30. By increasing the welding area between the base body 2 and the pattern piece 30 by the strips 30a, the welding strength between the base body 2 and the pattern piece 30 can be made stronger.

Pattern body 3 used in the method and device of the present invention
In the case of the illustrated embodiment, the positioning piece 35 is molded integrally with the die-cutting protrusion 31 on which the die-cutting force acts when the pattern body 3 is released from the mold. It goes without saying that the positioning piece 35 may be used as the positioning piece 35.

The connecting piece 32 that connects the pattern piece 30 and the positioning piece 35 is a so-called gate-like piece, and is preferably as thin as possible.
It is desirable that the pattern piece 30 has enough mechanical strength to not be easily cut by the pressure applied to the pattern piece 30 during injection molding.

The length of this connecting piece 32 is determined when the molds 4 and 5 for the base body 2 are clamped.
It is advantageous that the width of the effective mold clamping surface (the contact surface of the mold) is approximately the same as the width of the effective mold clamping surface (the contact surface of the mold) because unnecessary reliefs are not formed in the molds 4 and 5.

Further, in the case of the molding apparatus of the illustrated embodiment, each gate 21 is formed by branching from one runner 20, so that each divided base body 2 is molded simultaneously by a single injection machine. ing.

In addition, when two or more pattern pieces 30 are used, in order to handle the attachment of the pattern body 3 to the molds 4 and 5, as shown in FIG. It is convenient to combine it with

It is particularly advantageous if two or more pattern pieces 30 have different colors.

Also, at the same time as the base body 2 is molded, the base body 2 is molded.
Since the pattern body 3 and the pattern body 3 are firmly welded, it is recommended to use the die cutting protrusion 31 or the positioning piece 35 of the pattern body 3 as it is as a die cut piece when releasing the mold from the molds 4 and 5. This is advantageous in terms of the structure of the mold device.

〔Effect of the invention〕

As is clear from the above description, the present invention is not subject to any major restrictions on the form of the band-shaped color pattern, and the band-shaped color pattern can be made completely transparent. In addition, since the insert molding method is used, a molded product with high mechanical strength can be obtained, and the part that is molded first and provides part of the mold surface is placed inside the mold. Since it can be held firmly and immovably, there is no risk of defective molded products due to misalignment, etc. Furthermore, the pattern piece can be handled easily and accurately with the mold equipment, making molding operations easier. It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a molded product molded according to the present invention, FIG. 2 is a longitudinal cross-sectional view taken along line A-A in FIG. 1, and FIG. FIG. 3 is an enlarged vertical cross-sectional view showing an example of a joint surface with a pattern piece. FIG. 4 is a plan view showing an example of a pattern used for molding the molded product shown in FIG. 1, and FIG. 5 is a longitudinal cross-section taken along line B-B in FIG. It is a front view. FIG. 6 is a plan view showing an example of the base body and pattern body according to the present invention upon completion of molding. 7 is a longitudinal sectional view taken along the line C-C in FIG. 6 during molding according to the present invention, and FIG. 8 is a longitudinal sectional view taken along the line D-D in FIG. 6 during the same molding. FIG. Explanation of symbols, 1; Molded product, 2; Base body, 2
0; Runner, 21; Gate, 3; Pattern, 3
0; pattern piece, 30a; protruding stripe, 31; die-cut protruding stripe,
32; connecting piece, 34; coupling piece, 35; positioning piece, 4, 5; mold, 50; holding hole, 51; groove.

Claims (1)

[Scope of Claims] 1 The base body 2 and the pattern pieces 30 are arranged alternately in a form in which the base body 2 is divided into a desired number of pattern pieces 30 of a desired color, and the base body 2 of the pattern pieces 30
A method of molding a synthetic resin molded product having a band-shaped color pattern in which the top surface, bottom surface, and side end surfaces other than the end surface to be joined to the outside are exposed to the outside, and the method includes positioning the pattern piece 30 on both side end surfaces via connecting pieces 32 in advance. The piece 35 is integrally injection molded, and the positioning piece 35 is fixed at a location outside the mold surface of the molds 4 and 5. By fixing the positioning piece 35 to the molds 4 and 5, After holding the pattern piece 30 in a predetermined position in the molding space through the connecting piece 32 and clamping the molds 4 and 5, dedicated gates are placed in each of the molding spaces divided by the pattern piece 30. Base body 2 through 21
A method for molding a synthetic resin molded product having a band-like color pattern, in which the molded product 1 is molded by injection molding, and after releasing the mold, the connecting piece 32 and the positioning piece 35 are separated from the pattern piece 30. 2 Positioning pieces 35, which are integrally injection-molded on both side end surfaces of the pattern piece 30 via the connecting pieces 32, are tightly fitted into predetermined locations outside the mold surface of either or both of the molds 4 and 5. In addition, one or both of the molds 4 and 5 is provided with a groove 51 into which the connecting piece 32 is tightly fitted, and a molding space divided by the pattern piece 30 is formed. A molding apparatus for a synthetic resin molded product having a band-shaped color pattern, each of which is provided with a gate 21 having a flow passage cross-sectional area proportional to the volume of each molding space.