JPS6352570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing moldings for automobiles, and in particular, a method for producing moldings in which the main body of the molding is made of polyurethane resin and has an integral adhesive tape layer on its mounting surface. Regarding.

BACKGROUND OF THE INVENTION Band-shaped moldings are attached to the side surfaces of automobiles, front and rear bumpers, etc. to protect and decorate the automobile body. In recent years, plastic moldings that are lightweight, have excellent shock-absorbing performance, and are easy to process are often used for this molding, and the attachment of the molding to the car body has changed from mechanical fasteners such as clips to attachments to the car body. Since there is no need to drill mounting holes, the mounting process is simple and easy, and there is a shift toward adhesive tapes, which are free from the risk of rust.

By the way, in recent years, polyurethane resin molded products have been increasingly used for automobile exterior parts such as bumpers and fascias from the viewpoint of cushioning properties, etc. In relation to these, moldings attached to the outer surface of the car body are also made of different materials. In addition, due to requests for color matching through painting, etc., it is desired to use the same type of polyurethane resin product. However, although it is easy to mold the molding using polyurethane resin, it is extremely difficult to attach the molding to the vehicle body using adhesive means such as the above-mentioned adhesive tape for the following reasons. It was hot. In other words, molding of polyurethane resin is done by the well-known reaction injection molding method (RIM-Reaction Injection Molding) or, if it is a foamed product, by a cast molding method, but in either case, the molded product A film of a mold release agent used during molding is firmly formed on the outer surface, and cleaning and removing this mold release agent is a difficult task that is almost impossible. Unless the release agent is completely removed, bonding with an adhesive will be difficult and the advantages of adhesive tape as a means of attaching the molding cannot be enjoyed. Furthermore, foamed products have a problem in that the adhesive area (leakage area) with the adhesive decreases, making it impossible to obtain sufficient adhesive strength.

In view of this situation, the inventors of the present invention have conducted intensive research, and as a result of focusing on the special molding conditions of polyurethane resin, they have been able to provide a completely new method for producing moldings for automobiles.

An object of the present invention is to extremely simply and easily obtain a molding in which the main body of the molding is made of polyurethane resin and has an adhesive tape layer as a means for attaching the molding to the vehicle body.
The present invention also proposes an extremely simple manufacturing method for integrally forming a colored layer on the surface of a molding as a decorative body. Therefore, according to the present invention, it is now possible to firmly attach a molding made of polyurethane resin to a vehicle body using an adhesive, which has been considered difficult in the past, and the exterior of the molding as a decorative body is also extremely easy to attach. This can be done easily.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial perspective view of a molding for an automobile obtained by the present invention, and the molding 10 is a molding made of polyurethane resin. The adhesive tape layer 20 is integrally formed on the mounting surface 10a side of the main body 11, and the outer surface 1
A surface colored layer 12 is formed on the 0b side. In the figure, 24 is an adhesive, and 27 is a protective paper that protects the adhesive.

FIG. 2 shows a sectional view of a mold 30 in which the molding 10 shown in FIG. 1 is obtained by reaction injection molding (RIM), and an embodiment of the method of the invention will be explained with reference to the same figure. This mold 30 is the lower mold 3
1 and an upper mold 32, and a polyurethane resin mixing head 38 is connected to an injection port 34 communicating with a cavity 35 formed by both molds. 39 is a resin raw material supply hose. A recessed part 36 is formed on the cavity inner surface 35a which is the mounting surface 10a side of the molded product, and an adhesive tape 21 or 22 is applied to the recessed part 36 to form an adhesive tape layer 20 prior to injection of the raw resin. is retained.

Needless to say, the adhesive tape layer 20 serves as a means for attaching the molding 10 to the vehicle body.
The adhesive 24 on the outside surface is protected by a protective paper 27 until just before it is attached to the vehicle body, and the adhesive tape layer 20
The inner surface of the molding main body 11 is integrally fixed to the mounting surface of the molding main body as the raw resin hardens during molding of the molding main body 11. As the adhesive tape constituting this adhesive tape layer 20, there is a double-sided adhesive tape 21 or a single-sided adhesive tape 22 shown in FIGS. 3 and 4. In this invention, in the case of the former double-sided adhesive tape 21, the adhesive 25 on the inner side is bonded to the polyurethane resin raw material during molding, so almost all types of double-sided adhesive tape can be used, but the latter single-sided adhesive tape 22, it is necessary to consider the adhesiveness between the base material 23 and the polyurethane resin. According to experiments, the base material 25 is made of butyl rubber, chloroprene rubber,
It has been found that acrylic rubber or a foam thereof exhibits good bonding with polyurethane resin. Therefore, a single-sided adhesive tape is sufficient for those having these base materials. Adhesive 2
As 4 and 25, a known butel rubber-based or acrylic-based adhesive or pressure-sensitive adhesive is used.

Note that the adhesive tape 21 or 22 is
Although not shown, the upper die 32 may be provided with a suitable vacuum suction hole and adsorbed to the inner bottom surface of the concave portion 36, or it may be held between the edges of the die, or it may be temporarily fixed with other tape or the like. This can be done by, for example,

What is important here is that the reason why it is possible to hold the above-mentioned adhesive tape in a mold and inject the raw resin before molding is due to the special molding conditions of the polyurethane resin molding process. Simply put, when molding the aforementioned polyurethane resin, the pressure conditions during molding are extremely low compared to those of ordinary thermoplastic resins. Therefore, it is possible to set adhesive tape inserts, which would be impossible due to crushing during injection molding of ordinary thermoplastic resins, when molding this polyurethane resin. At the same time, in the case of polyurethane resin liquid raw materials or those currently in production, they have good wettability with the adhesive of the adhesive tape set in the insert or its base material, and of course are completely unaffected by the release agent. It has extremely good bonding properties.

Furthermore, in the present invention, the molding 10
A paint constituting the surface colored layer 12 is applied to the cavity inner surface 35b which becomes the outer surface 10b of the coating film 1.
2' is preformed. Cavity inner surface 3
As the paint applied to 5, a one-component or two-component urethane paint containing a desired pigment is preferably used. Note that acrylic paint may also be used.
The thickness of the coating film 12' is usually 2 to 3 microns or more.

After holding the adhesive tape and forming the coating film, the polyurethane resin raw material is transferred to the mixing head 3.
8 and injection port 34 into the cavity 35, and molding is mainly performed. At this time, the resin raw material or its preparation is integrally and firmly bonded to the inner surface of the adhesive tape and the inner surface of the coating film, has an integral adhesive tape layer as a means of attachment to the vehicle body, and has an adhesive tape layer on the outer surface. A molding having a desired surface coloring layer is formed.

FIG. 5 shows a cross-sectional view of a mold 40 in the case of cast molding of polyurethane resin, where 41 is a lower mold;
Reference numeral 42 indicates an upper mold, 45 a cavity, and 46 a recessed portion, and the holding of the adhesive tape 21 or 22 and the formation of the coating film 12' are exactly the same as in the above embodiment.

As is clear from the above explanation, according to the present invention, it is now possible to use adhesive tape as a means of attaching moldings made of polyurethane resin, which had been considered difficult in the past. Since layers are formed, it has become possible to realize it extremely simply and economically. At the same time, since the colored layer on the outer surface, which is essential as a decorative body, is formed at the same time as the molding, the present invention can provide an extremely practical and economical manufacturing method for this type of molding. .

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an example of molding obtained by the present invention, FIG. 2 is a sectional view of a reaction injection molding die showing an embodiment of the invention, and FIG.
4 and 4 are cross-sectional views of the adhesive tape used in the present invention, and FIG. 5 is a cross-sectional view of a cast molding die showing another embodiment of the present invention. 10... Molding, 11... Molding main body, 12... Surface colored layer, 20... Adhesive tape layer, 21, 22... Adhesive tape, 30, 40
...Mold, 31, 41...Lower mold, 32, 42...
...Upper mold, 35, 45...Cavity, 36, 46
...concavity.

Claims (1)

[Claims] 1 A concave portion is provided on the inner surface of the cavity of the molding die, which is the mounting surface side of the molding, and an adhesive tape, which is a means of attaching to the vehicle body, is held in advance in the concave portion, and the inner surface of the cavity, which is the outer surface side of the molding. A method for producing moldings for automobiles, characterized in that a paint forming a surface colored layer is applied to the surface of the molding, and then a polyurethane resin raw material is injected to perform molding-based molding.