JPS6036112A - Molding of multicolor resin - Google Patents

Abstract

PURPOSE:To improve the workability and productivity by arranging at least two adjacent ones among resin members to be held to be an integrated moldings having joints for joining them while a number of these members are inserted securely into a deformed mold surface of a molding die in a relatively simple manner and for a short time. CONSTITUTION:Members 1 to be held representing five characters T, U, R, B and O are injection molded lintegrally by the ordinary injection molding from a red-colored ethylene vinyl acetate copolymerized resin and the adjacent characters are connected to each other with a joint 16. The molding die used is a mold 2 for forming a mad gaurd which has the character T, U, R, B and O formed on the molding surface of one die 21 as dents 211. A pin 3 is formed on the molding surface of the other die 22. The pin 3 is made up of a round bar-shaped piston section 31 inserted into a cylindrical vertical hole 221 provided on the molding surface of the die 22 and a spring 32 grasped with the bottom surface of the vertical hole 221 and the end face of the piston section 21.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an improvement in a multicolor resin molding method in which resin is filled and assimilated into a cavity while a plurality of resin members to be held are fixed to the mold surface. .

(Prior art) A plurality of letters, symbols, etc. are projected on the surface of a resin molded body,
A multicolor resin molding method is known as a method for obtaining a resin molded product in which the protruding portion is colored differently from other portions.

In the conventional multicolor resin molding method, concave portions containing letters, figures, etc. are formed on the surface of the mold that forms the kitobidi, and these four portions are covered with letters, patterns, etc. that are separately molded by injection molding, etc. The holding member is inserted once to fix these held members to the mold surface, then the molded piece is closed, and a resin is injected into the cavity and solidified to produce the molded object.This conventional method is as follows: When the number of parts to be held increases, each of the many types of parts to be held must be inserted into each of the four predetermined mold surfaces, so inserting the parts to be held into the mold surface becomes complicated and takes a lot of time. This was hindering productivity.

The present invention overcomes the above-mentioned problems, and even if the present invention has a large number of held members, the large number of held members can be moved relatively easily and in a short time into a recess formed on the mold surface of a mold. The object of the present invention is to provide a multicolor resin molding method that can be inserted and fixed into a mold, has excellent workability, and is highly productive.

That is, in the multicolor resin molding method of the present invention, two or more mutually independent recesses formed on the mold surface of a mold are molded with a specific color and a shape corresponding to each recess. a step of fixing at least one resin member to be held in each of the recesses;
In the multicolor resin molding method, the process of sequentially filling and assimilating resins having different colors into cavities of a mold to which the held members are fixed includes at least two adjacent resins of the held resin members. The resin members to be held are characterized in that they are integrally molded with joints for joining them.

At least two resin held members joined at the joint are integrally molded by injection molding, compression molding, or the like. Note that the resin forming the held member includes thermoplastic resin,
Any thermosetting resin may be used. It is not preferable for the joint portion to be exposed on the mold surface where the member to be held is exposed. As far as possible, the joints are preferably embedded in a resin crystallization of another color which is subsequently molded. If there is no problem even if the joint appears on the back side of the final molded product, the joint may be exposed on the back side.

As the mold used in the molding method of the present invention, the same mold as conventional molds can be used. If it is necessary that the joint of the held member not be exposed on the back side of the molded multicolored resin, the mold surface forming the back side may have a bottle that protrudes from the mold surface using a constant biasing force such as a spring. It is preferable to use a mold.

In this mold, the joined part of the held member is held in the center of the cavity by a bottle, filled with resin of another color, and the resin molded LIT-bottle is pushed back into the mold and joined. securely hold it in the center of the cavity,
It is embedded in the resin after it is injected into the cavity. If the member to be held is the same type of thermoplastic resin as the resin with another color that will be injected later, when molding the resin with the same color, the molten resin injected into the cavity may The joint of the held member is heated, partially melts, and deforms into small horns. For this purpose, it is preferable to use a mold with a bottle that holds the joint portion in the cavity with the above-mentioned constant biasing force.

The first step of the molding method of the present invention is a step of fixing the member to be held integrally molded at the joint described above to the mold described above. In this step, since the members to be held are integrated, there is no need to select one member to be held from a large number of members. For this reason, simply take the held member that is integrated,
The first step is accomplished by carrying it to the mold and attaching it to the mold once. Note that even when the individual members to be held are attached and fixed to the recesses of a plurality of molds, the individual members to be held are joined at the joint portion. Therefore, it is possible to integrally fix a plurality of held members into a plurality of four parts ('I +f).

The second step is a step of clamping the mold to which the member to be held is fixed, and filling and assimilating a resin of another color into the cavity. When the mold has a pin that presses the joint of the member to be held, the pin holds the joint in the center of the cavity with a constant biasing force by ql) tightening. In this state, molten resin of another color is injected into the cavity. Injection can be performed by injection molding or transfer molding. As the resin, thermoplastic resin, thermosetting resin, uncrosslinked rubber, etc. can be used. The resins G and L are injected into the mold cavity by injection pressure and fill the cavities. At this time, the member to be held is partially embedded in the injected resin. Then, in the cavity, the resin that gives the other colors solidifies by cooling, solidification, crosslinking reaction, etc.

As a result, a multicolored resin according to the method of the present invention is molded. After this, the mold is removed and the multicolored resin is removed.

In the method of the present invention, even when a large number of members to be held are exposed on the surface of a molded product, each member to be held is connected at a joint, so that the members to be held can be placed in the mold of the mold. The operation becomes very easy when inserting into the respective recess of the surface. Furthermore, when fixed in the mold,
When holding the joints connecting the held members in a row at the center of the groove using a bottle biased with a constant biasing force, the product value is reduced because the joints are not exposed on the surface of the resulting molded product. High quality multicolored resin molded products can be obtained.

Examples will be described below.

First, a red-colored ethylene vinyl acetate copolymer resin was molded using the usual injection molding method.
Figure 2 shows the cross section of the five letters T, LJ, R, B,
The held member 1 made of 0 was integrally injection molded. Each character 11 to 15 constituting this held member 1 has a thickness of approximately 3I.
llII11 Height approx. 2011111° Width 25+nI
I+, each adjacent letter being connected by a joint 16. Each joint 16 is connected at each connecting part on the back side of each character 11 to 15 as shown in FIG. be.

The mold used in this example is a mold 2 for molding a mudguard for a passenger car, and FIG. 3 shows a partial cross-sectional view of the mold with the member to be held inserted. The letters T, U, R, B, and O are formed as recesses 211 on the mold surface of the mold 21 of one degree J of the mold 2. A bottle 3 shown in FIG. 3 is formed on the mold surface of the other 'l'l 22.

This bottle 3 consists of a round rod-shaped piston part 31 inserted into a cylindrical vertical hole 221 formed in the mold surface of the mold 22, and a spring clamped between the bottom surface of the vertical hole 221 and the j-receiving end surface of the piston part 21. It consists of 32.

Each of the letters 11 to 15 of the member to be held 1 was inserted and fixed into each recess 211 of one mold 21 of this mold 2. Next, a J-shaped reinforcing metal serving as a reinforcing material for the mudguard was inserted into this mold, and the mold was closed. When the mold is closed, the -1- face of the piston portion 31 of the bottle 3 comes into contact with the back side of the joint 16 of the member to be held 1, and holds the joint 16 in the center of the cavity 2a. In this state, a black ethylene vinyl acetate copolymer resin made of the same resin as the member to be held 1 was subjected to q/J molding to produce a mudguard (not shown in FIG. 4). This mudguard had T, U, R, B, and O exposed in red on the surface of the molded product, and all other surfaces were molded from black resin. A cross section of this molded product is shown in FIG. The joint of the resin member to be held was partially melted and deformed by the heat during molding. However, the joints were not exposed on the surface of the mudguard.

Conventionally, in order to manufacture this mudguard, five types of resin held members with five independent letters, T, UlR, B, and 0, were made, and one holding member was selected from the five. , inserted into a predetermined type of recess. Selecting this specific member to be held and inserting it into the recess of the mold that matches it is very complicated, and requires a step of selecting the member to be held five times and transporting it to the mold surface and fixing it. did.

In an embodiment of the invention, one degree at a time, U, R, B.

It becomes possible to bring the held member of 0 to the mold surface,
Since there is no need to select the member to be held and the member to be held only needs to be carried in once, work efficiency has been significantly improved. Further, due to the action of the bottle 3 of the mold, the joint portion could be reliably embedded in the resin which would harden later, making it possible to manufacture a multicolored resin molded product with high commercial value.

[Brief explanation of the drawing]

Fig. 1 is a front view of the member to be held 1 used in the embodiment of the present invention, Fig. 2 is a sectional view taken along the ■-■ arrow in Fig. 1, and Fig. 3 is the member to be held 1 fixed to the molding 2. Molding mold 2 in a closed state
FIG. 4 is a cross-sectional view of the main parts of the IC
A perspective view of the molded product, and FIG. 5 is a sectional view taken along the line v--■ in FIG. 4. 1... Member to be held 2... Molding 3... Bottle 16... Joint patent applicant Dingguchi] Gosei Co., Ltd. > 1 Agent Patent attorney Hirodo Okawa Patent attorney Hijiyuki Shudo Patent attorney Maruyama Akio

Claims (2)

[Claims] (1) Two or more resin held members having a specific color and molded into shapes corresponding to the respective recesses are placed in two or more independent recesses formed on the mold surface of the mold. In a multicolor resin molding method, in which a step of fixing the held member in each of the recesses, and a step of filling and solidifying a resin having another color into the cavity of the mold to which the held member is fixed, the resin held member is A multicolor resin molding method characterized in that at least two resin held members adjacent to each other among the members are integrally molded with a joint portion for joining them. (2) The joint part of the integrally molded product is held in the center of the cavity of the mold with a bottle biased by a window bias force, and a resin having a different color is filled and assimilated in the process of the patent claim. A multicolor resin molding method according to scope 1.