JPS6110409A - Molding process of in-mold coating - Google Patents

Abstract

PURPOSE:To cure rapidly the synthetic resin material adjacent to a paint bung hole at molding by placing the synthetic resin material of low temperature curing type in the paint injecting portion of a stationary mold, while placing a molding material in the stationary mold. CONSTITUTION:While the molding material cut into a suitable size is placed in the molding part 1a of a stationary mold 1, the synthetic resin M of low temperature curing type is placed therein. A movable mold 2 is raised at the stage where about 90% of the molding material has been cured, and simultaneously, the paint supplied from a pipe 5 is injected from a nozzle 3, operating a cylinder 4, whereby the paint T is extruded on the surface of a molded product Wa in the molds 1, 2. After the paint has been injected, the movable mold 2 is again clamped on the stationary mold 1, and the paint T is cuased to flow uniformly on the whole surface of the molded product Wa. Then, the molded product Wa and the paint T are cured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an in-mold coating molding method suitable for molding a molding material consisting of a sheet molding compound.

[Prior art]

Conventionally, when molding material made of sheet molding compound is molded using the in-mold coating molding method, the molding material is placed on the molding area of a fixed mold, the movable mold is clamped to the fixed mold, and the molding material is After the movable mold is slightly raised during the curing stage, paint is injected onto the surface of the molded product during the curing stage, and the movable mold is then clamped to the fixed mold to form the product.

However, the paint used during in-mold coating molding is easily affected by the heat from the mold that is heated to around 150° C., and there is always the problem of curing and denaturation. For this reason, the paint injection unit connected to the high-temperature mold is always cooled to a low temperature with cooling water or the like to prevent the paint from denaturing or hardening. However, in this cooling method, the paint injection unit and the adjacent mold are simultaneously cooled, which not only causes problems such as making it difficult for the molding material near the paint injection port to harden, but also causes the problem that the molding material near the paint injection port If the molding material is not cured, there are problems that cause molding defects such as poor release of the molded product, obstruction of paint flow, and uncured resin being washed away by the injected paint.

[Purpose of the invention]

The present invention was made to solve the above-mentioned problems, and its purpose is to place a low-temperature curing synthetic resin material on the paint injection site of the fixed mold at the same time as placing the molding material on the fixed mold. Therefore, it is an object of the present invention to provide an in-mold coating molding method that can rapidly harden the synthetic resin material near the paint injection port and prevent molding defects from occurring.

[Structure of the invention]

In order to achieve the above object, the in-mold coating molding method according to the present invention has a structure in which a molding material made of sheet molding compound is placed on a molding part of a fixed mold, and a movable mold is clamped to the fixed mold. Then, during the curing stage of the molding material, the movable mold is raised and lowered, and the coating 11 is injected onto the surface of the molded product at the curing stage, and the movable mold is further clamped to the fixed mold and molded. An in-mold coating molding method, wherein the molding material is placed on the fixed mold.
At the same time, after a low-temperature curing synthetic resin material is placed on the paint injection site of the fixed mold, the movable mold is clamped to the fixed mold.

The low-temperature curing synthetic resin material is not particularly limited, and the curing temperature is between 100°C and 130°C.
A material that cures within the temperature range of °C is suitable; if the curing temperature is below 00 °C, it will harden faster than the molding material made of sheet molding compound, and the compatibility with the molding material that will be cured later will be reduced. Solubility may decrease.

Furthermore, if the curing temperature is 130° C. or higher, the paint may be in an uncured state like the molding material due to the influence of cooling of the paint injection unit. Low-temperature curing synthetic resin materials that are compatible with this curing temperature are
It is manufactured as appropriate by selecting materials such as a polymerization initiator, filler, thickener, and adjusting the blending ratio.

Further, the type of synthetic resin is not particularly limited, but one that is compatible with the synthetic resin material used for the molding material and has a coefficient of thermal expansion as close as possible is suitable.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

(First Example) FIG. 1 shows a process diagram of an in-mold coating molding method according to the present invention.

In (a) or b) of FIG. 1, 1 is a fixed mold, and the upper surface of this fixed mold 1 has a molding part 1 that opens upward.
A and a tab portion 1b are formed, and the periphery thereof is a flat contact surface IC. Further, a movable mold 2 is arranged on the upper part of the fixed mold 1, and a protrusion 2a is formed on the lower surface of the movable mold 2 to be accommodated in the molding part 1a of the fixed mold 1. It is a flat abutting surface 2b that abuts the abutting surface 1c.

Further, the movable mold 2 is formed with a through hole 2C that communicates with the tab portion 1b of the fixed mold 1, and a nozzle 3 for injecting paint is fitted into the through hole 2C.

The lower end of this nozzle 3 is connected to the tab portion 1b of the fixed mold 1.
The air cylinder 4 is provided at the upper end. Further, a vibrator 5 whose one end is connected to a paint supply source (not shown) is connected in the middle of the nozzle 3.
A cooler 6 in which a number of passages 6a are formed through which cooling water passes is provided at the connection portion.

When molding the molding material W made of sheet molding compound, first, the fixed mold 1 and the movable mold 2 are heated to around 150°C, and as shown in FIG. 1(a), The movable mold 2 is released from the fixed mold 1. next,
A molding material W cut to an appropriate size is subjected to taH on the molding part 1a of the fixed mold 1, and a low-temperature curing synthetic resin piece M that hardens in the range of 100 to 130°C is placed on the tab part 1b.
Place.

Thereafter, the movable mold 2 is clamped to the fixed mold 1 as shown in FIG. do. Accordingly, the low-temperature curing synthetic resin piece M is cured more than the molding material W by the heat of the mold 1.2, and the molding material W is also further hardened. Then, when the molding material W has been hardened to about 90%, the movable mold 2 is moved slightly by about one fin.

At the same time, the air cylinder 4 is operated to inject the paint supplied from the pipe 5 from the nozzle 3, and the paint T is applied to the molded body W in the mold 1.2 as shown in FIG. 1(C).
Push it out onto the surface of a.

At this time, the synthetic resin piece M near the injection port for the paint T has already hardened, and the paint T flows smoothly and is swept onto the surface of the molded body Wa.

After injecting the paint, the movable mold 2 is again clamped to the fixed mold 1, and the paint T is uniformly flushed over the entire surface of the molded body Wa, and the molded body Wa and the paint T are cured. After that, the movable mold 2 is released from the fixed mold l, and the molding part 1a of the fixed mold 1 is
is opened and the molded product wb on which the coating film T is formed is taken out. The molded product wb taken out is shown in FIG. 1(d).
As shown in the figure, the molded body Wc of the unnecessary tab portion 1b is cut off after being transported to the trimming process to form the final molded product wb.
is obtained.

(Second Example) FIG. 2 shows a cross-sectional view of a molded article obtained in a second example of the present invention.

In this second embodiment, a molded article without a tab portion is obtained, and the molding method for obtaining the molded article is the same as in the first embodiment. Therefore, a description of the molding method will be omitted.

In FIG. 2, wb is a molded product obtained in the same manner as in the first embodiment, and this molded product wb does not have a tab portion, and the low-temperature curing synthetic resin piece M is also part of the molded product wb. It is said that Therefore, a boundary appears between the molded body Wa of the molding material made of the sheet molding compound and the low-temperature curing synthetic resin piece M, and even when the paint T is applied, there may be a step difference of 4L.

In order to solve this problem, concealment measures as shown in FIGS. 3 and 4 are taken. That is, FIG. 3 shows the molded product Wb
When assembling, another part P is placed over the part of the synthetic resin piece M that causes a step. Further, in FIG. 4, when assembling the molded product wb, similar to FIG. 3, the portion of the synthetic resin piece M that causes a step is covered up by an ornament E such as an emblem or a molding. This eliminates the difference in level at the boundary, and prevents poor appearance after assembly.

〔Effect of the invention〕

As explained above, in the in-mold coating molding method according to the present invention, a low-temperature curing synthetic resin material is placed on the paint injection site of the fixed mold at the same time as the molding material is placed on the fixed mold. This has the effect of rapidly curing the synthetic resin material near the paint injection port during molding.

Further, in the present invention, the following effects can be obtained by rapidly curing the synthetic resin material near the paint injection port.

(1) It is possible to prevent the occurrence of molding defects such as poor release of the molded product due to uncured molding material, obstruction of paint flow, and washing away of uncured resin by injected paint.

(2) The insulation means for the part where the paint is injected into the mold can be simplified.

(3) It is possible to eliminate the need for a cooling control mechanism for the part where paint is injected into the mold.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of an in-mold coating molding method according to the present invention. FIG. 2 is a sectional view of a molded article obtained in a second embodiment of the present invention. 3 and 4 are cross-sectional views illustrating the concealing means in the second embodiment of the present invention. 1...Fixed mold 1a...Molding part 1 b---Tab part IC---One contact surface 2---Movable mold 2 a--- -Protrusion 2b---5 contact surface 2c---Continuous through hole 3・-Nozzle 4---Air cylinder 5---11 Pipe 6---Cooler 6a---Passage W-1 ~---Molding material W a---Molded body w b---Molded article W c, -1・Molded body M------・Synthetic resin piece T- ...Paint P-111~Parts E-1--Decorations

Claims (1)

[Claims] A molding material made of sheet molding compound is placed on the molding section of the fixed mold, the movable mold is clamped to the fixed mold, and the movable mold is slightly raised during the curing stage of the molding material, and the molding at the curing stage is completed. An in-mold coating molding method in which paint is injected onto the surface of the product, and then a movable mold is clamped to a fixed mold to form the product, and the paint is injected into the fixed mold at the same time as the molding material is placed on the fixed mold. An in-mold coating molding method characterized by placing a low-temperature curing synthetic resin material on a part and then clamping a movable mold to a fixed mold.